| blob | fb2448a26e968433c7705853ce1944ae36cb8d22 |
1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2024 Free Software Foundation, Inc.
3 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
4 Rewritten by Jason Merrill (jason@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Known bugs or deficiencies include:
24 all methods must be provided in header files; can't use a source
25 file that contains only the method templates and "just win".
27 Fixed by: C++20 modules. */
52 /* The type of functions taking a tree, and some additional data, and
53 returning an int. */
56 /* The PENDING_TEMPLATES is a list of templates whose instantiations
57 have been deferred, either because their definitions were not yet
58 available, or because we were putting off doing the work. */
60 {
63 };
77 /* Live only within one (recursive) call to tsubst_expr. We use
78 this to pass the statement expression node from the STMT_EXPR
79 to the EXPR_STMT that is its result. */
82 // -------------------------------------------------------------------------- //
83 // Local Specialization Stack
84 //
85 // Implementation of the RAII helper for creating new local
86 // specializations.
89 {
91 ;
94 else
96 }
99 {
101 {
104 }
105 }
107 /* True if we've recursed into fn_type_unification too many times. */
111 {
115 };
117 /* The general template is not in these tables. */
122 /* Contains canonical template parameter types. The vector is indexed by
123 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
124 TREE_LIST, whose TREE_VALUEs contain the canonical template
125 parameters of various types and levels. */
128 #define UNIFY_ALLOW_NONE 0
129 #define UNIFY_ALLOW_MORE_CV_QUAL 1
130 #define UNIFY_ALLOW_LESS_CV_QUAL 2
131 #define UNIFY_ALLOW_DERIVED 4
132 #define UNIFY_ALLOW_INTEGER 8
133 #define UNIFY_ALLOW_OUTER_LEVEL 16
134 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
135 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
138 tbr_incomplete_type,
139 tbr_ambiguous_baseclass,
140 tbr_success
141 };
230 /* Make the current scope suitable for access checking when we are
231 processing T. T can be FUNCTION_DECL for instantiated function
232 template, VAR_DECL for static member variable, or TYPE_DECL for
233 for a class or alias template (needed by instantiate_decl). */
235 void
237 {
249 /* An artificial deduction guide should have the same access as
250 the constructor. */
252 else
256 {
259 }
260 }
262 /* Restore the scope set up by push_access_scope. T is the node we
263 are processing. */
265 void
267 {
277 else
279 }
281 /* Do any processing required when DECL (a member template
282 declaration) is finished. Returns the TEMPLATE_DECL corresponding
283 to DECL, unless it is a specialization, in which case the DECL
284 itself is returned. */
286 tree
288 {
295 {
296 tree type;
304 {
308 }
310 }
315 {
317 {
320 }
321 else
323 }
324 else
329 }
331 /* Create a template info node. */
333 tree
335 {
340 }
342 /* DECL_TEMPLATE_INFO, if applicable, or NULL_TREE. */
344 static tree
346 {
347 /* This needs to match template_info_decl_check. */
350 {
364 }
366 }
368 /* Return the template info node corresponding to T, whatever T is. */
370 tree
372 {
394 }
396 /* Returns the template nesting level of the indicated class TYPE.
398 For example, in:
399 template <class T>
400 struct A
401 {
402 template <class U>
403 struct B {};
404 };
406 A<T>::B<U> has depth two, while A<T> has depth one.
407 Both A<T>::B<int> and A<int>::B<U> have depth one, if
408 they are instantiations, not specializations.
410 This function is guaranteed to return 0 if passed NULL_TREE so
411 that, for example, `template_class_depth (current_class_type)' is
412 always safe. */
414 int
416 {
420 {
430 {
433 else
435 }
438 else
440 }
443 }
445 /* Return TRUE if NODE instantiates a template that has arguments of
446 its own, be it directly a primary template or indirectly through a
447 partial specializations. */
448 static bool
450 {
462 /* So now we know we have a specialization, but it could be a full
463 or a partial specialization. To tell which, compare the depth of
464 its template arguments with those of its context. */
473 }
475 /* Subroutine of maybe_begin_member_template_processing.
476 Returns true if processing DECL needs us to push template parms. */
478 static bool
480 {
486 }
488 /* Subroutine of maybe_begin_member_template_processing.
489 Push the template parms in PARMS, starting from LEVELS steps into the
490 chain, and ending at the beginning, since template parms are listed
491 innermost first. */
493 static void
495 {
503 current_template_parms
511 NULL);
513 {
522 {
529 /* Push the CONST_DECL. */
535 }
536 }
537 }
539 /* Restore the template parameter context for a member template, a
540 friend template defined in a class definition, or a non-template
541 member of template class. */
543 void
545 {
546 tree parms;
551 {
554 /* Disregard full specializations (c++/60999). */
557 }
560 {
565 {
568 }
571 }
573 /* Remember how many levels of template parameters we pushed so that
574 we can pop them later. */
576 }
578 /* Undo the effects of maybe_begin_member_template_processing. */
580 void
582 {
591 {
595 }
596 }
598 /* Return a new template argument vector which contains all of ARGS,
599 but has as its innermost set of arguments the EXTRA_ARGS. */
601 tree
603 {
604 tree new_args;
622 }
624 /* Like add_to_template_args, but only the outermost ARGS are added to
625 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
626 (EXTRA_ARGS) levels are added. This function is used to combine
627 the template arguments from a partial instantiation with the
628 template arguments used to attain the full instantiation from the
629 partial instantiation.
631 If ARGS is a TEMPLATE_DECL, use its parameters as args. */
633 tree
635 {
636 tree new_args;
641 {
644 }
646 /* If there are more levels of EXTRA_ARGS than there are ARGS,
647 something very fishy is going on. */
650 /* If *all* the new arguments will be the EXTRA_ARGS, just return
651 them. */
655 /* For the moment, we make ARGS look like it contains fewer levels. */
660 /* Now, we restore ARGS to its full dimensions. */
664 }
666 /* Return the N levels of innermost template arguments from the ARGS. */
668 tree
670 {
671 tree new_args;
677 /* If N is 1, just return the innermost set of template arguments. */
681 /* If we're not removing anything, just return the arguments we were
682 given. */
688 /* Make a new set of arguments, not containing the outer arguments. */
695 }
697 /* The inverse of get_innermost_template_args: Return all but the innermost
698 EXTRA_LEVELS levels of template arguments from the ARGS. */
700 static tree
702 {
703 tree new_args;
709 /* If N is 1, just return the outermost set of template arguments. */
713 /* If we're not removing anything, just return the arguments we were
714 given. */
719 /* Make a new set of arguments, not containing the inner arguments. */
726 }
728 /* We've got a template header coming up; push to a new level for storing
729 the parms. */
731 void
733 {
734 /* We use a non-tag-transparent scope here, which causes pushtag to
735 put tags in this scope, rather than in the enclosing class or
736 namespace scope. This is the right thing, since we want
737 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
738 global template class, push_template_decl handles putting the
739 TEMPLATE_DECL into top-level scope. For a nested template class,
740 e.g.:
742 template <class T> struct S1 {
743 template <class T> struct S2 {};
744 };
746 pushtag contains special code to insert the TEMPLATE_DECL for S2
747 at the right scope. */
753 /* Add a dummy parameter level while we process the parameter list. */
754 current_template_parms
757 current_template_parms);
758 }
760 /* This routine is called when a specialization is declared. If it is
761 invalid to declare a specialization here, an error is reported and
762 false is returned, otherwise this routine will return true. */
764 static bool
766 {
769 /* [temp.expl.spec]
771 An explicit specialization shall be declared in the namespace of
772 which the template is a member, or, for member templates, in the
773 namespace of which the enclosing class or enclosing class
774 template is a member. An explicit specialization of a member
775 function, member class or static data member of a class template
776 shall be declared in the namespace of which the class template
777 is a member. */
779 {
782 }
784 /* [temp.expl.spec]
786 In an explicit specialization declaration for a member of a class
787 template or a member template that appears in namespace scope,
788 the member template and some of its enclosing class templates may
789 remain unspecialized, except that the declaration shall not
790 explicitly specialize a class member template if its enclosing
791 class templates are not explicitly specialized as well. */
793 {
796 }
799 }
801 /* We've just seen template <>. */
803 bool
805 {
809 }
811 /* Called at then end of processing a declaration preceded by
812 template<>. */
814 void
816 {
819 }
821 /* Any template <>'s that we have seen thus far are not referring to a
822 function specialization. */
824 void
826 {
829 }
831 /* We've just seen a template header. If SPECIALIZATION is nonzero,
832 it was of the form template <>. */
834 static void
836 {
838 template_header_count++;
839 }
841 /* We're beginning an explicit instantiation. */
843 void
845 {
848 }
851 void
853 {
856 }
858 /* An explicit specialization or partial specialization of TMPL is being
859 declared. Check that the namespace in which the specialization is
860 occurring is permissible. Returns false iff it is invalid to
861 specialize TMPL in the current namespace. */
863 static bool
865 {
868 /* [tmpl.expl.spec]
870 An explicit specialization shall be declared in a namespace enclosing the
871 specialized template. An explicit specialization whose declarator-id is
872 not qualified shall be declared in the nearest enclosing namespace of the
873 template, or, if the namespace is inline (7.3.1), any namespace from its
874 enclosing namespace set. */
877 {
880 }
883 /* Same or enclosing namespace. */
885 else
886 {
887 auto_diagnostic_group d;
893 }
894 }
896 /* SPEC is an explicit instantiation. Check that it is valid to
897 perform this explicit instantiation in the current namespace. */
899 static void
901 {
902 tree ns;
904 /* DR 275: An explicit instantiation shall appear in an enclosing
905 namespace of its template. */
911 }
913 /* Returns true if TYPE is a new partial specialization that needs to be
914 set up. This may also modify TYPE to point to the correct (new or
915 existing) constrained partial specialization. */
917 static bool
919 {
920 /* An implicit instantiation of an incomplete type implies
921 the definition of a new class template.
923 template<typename T>
924 struct S;
926 template<typename T>
927 struct S<T*>;
929 Here, S<T*> is an implicit instantiation of S whose type
930 is incomplete. */
934 /* It can also be the case that TYPE is a completed specialization.
935 Continuing the previous example, suppose we also declare:
937 template<typename T>
938 requires Integral<T>
939 struct S<T*>;
941 Here, S<T*> refers to the specialization S<T*> defined
942 above. However, we need to differentiate definitions because
943 we intend to define a new partial specialization. In this case,
944 we rely on the fact that the constraints are different for
945 this declaration than that above.
947 Note that we also get here for injected class names and
948 late-parsed template definitions. We must ensure that we
949 do not create new type declarations for those cases. */
951 {
955 /* If there are no template parameters, this cannot be a new
956 partial template specialization? */
960 /* The injected-class-name is not a new partial specialization. */
964 /* If the constraints are not the same as those of the primary
965 then, we can probably create a new specialization. */
969 {
973 }
975 /* Also, if there's a pre-existing specialization with matching
976 constraints, then this also isn't new. */
979 {
985 {
988 }
990 }
992 /* Create a new type node (and corresponding type decl)
993 for the newly declared specialization. */
998 /* We only need a separate type node for storing the definition of this
999 partial specialization; uses of S<T*> are unconstrained, so all are
1000 equivalent. So keep TYPE_CANONICAL the same. */
1003 /* Build the corresponding type decl. */
1014 }
1017 }
1019 /* The TYPE is being declared. If it is a template type, that means it
1020 is a partial specialization. Do appropriate error-checking. */
1022 tree
1024 {
1025 tree context;
1030 /* A lambda that appears in specialization context is not itself a
1031 specialization. */
1035 /* An injected-class-name is not a specialization. */
1040 {
1044 }
1049 {
1055 else
1058 }
1060 {
1061 /* This is for ordinary explicit specialization and partial
1062 specialization of a template class such as:
1064 template <> class C<int>;
1066 or:
1068 template <class T> class C<T*>;
1070 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
1073 {
1080 {
1085 }
1086 }
1092 /* Trying to define a specialization either without a template<> header
1093 or in an inappropriate place. We've already given an error, so just
1094 bail now so we don't actually define the specialization. */
1096 }
1102 {
1103 /* This is for an explicit specialization of member class
1104 template according to [temp.expl.spec/18]:
1106 template <> template <class U> class C<int>::D;
1108 The context `C<int>' must be an implicit instantiation.
1109 Otherwise this is just a member class template declared
1110 earlier like:
1112 template <> class C<int> { template <class U> class D; };
1113 template <> template <class U> class C<int>::D;
1115 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1116 while in the second case, `C<int>::D' is a primary template
1117 and `C<T>::D' may not exist. */
1121 {
1122 tree t;
1127 {
1130 type))
1133 }
1135 /* Check for invalid specialization after instantiation:
1137 template <> template <> class C<int>::D<int>;
1138 template <> template <class U> class C<int>::D; */
1142 {
1146 {
1147 /* We already have a full specialization of this partial
1148 instantiation, or a full specialization has been
1149 looked up but not instantiated. Reassign it to the
1150 new member specialization template. */
1151 spec_entry elt;
1164 spec_entry **slot
1169 }
1170 else
1171 /* But if we've had an implicit instantiation, that's a
1172 problem ([temp.expl.spec]/6). */
1175 }
1177 /* Mark TYPE as a specialization. And as a result, we only
1178 have one level of template argument for the innermost
1179 class template. */
1184 }
1185 }
1187 {
1188 /* Someday C++0x may allow for enum template specialization. */
1193 else
1194 {
1197 }
1198 }
1201 }
1203 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1204 gone through coerce_template_parms by now. */
1206 static void
1208 {
1210 {
1219 /* Allow typedefs on the type of a non-type argument, since a
1221 else
1223 }
1224 }
1226 static void
1228 {
1233 }
1235 /* Retrieve the specialization (in the sense of [temp.spec] - a
1236 specialization is either an instantiation or an explicit
1237 specialization) of TMPL for the given template ARGS. If there is
1238 no such specialization, return NULL_TREE. The ARGS are a vector of
1239 arguments, or a vector of vectors of arguments, in the case of
1240 templates with more than one level of parameters.
1242 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1243 then we search for a partial specialization matching ARGS. This
1244 parameter is ignored if TMPL is not a class template.
1246 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1247 result is a NONTYPE_ARGUMENT_PACK. */
1249 static tree
1251 {
1261 /* There should be as many levels of arguments as there are
1262 levels of parameters. */
1271 /* Lambda functions in templates aren't instantiated normally, but through
1272 tsubst_lambda_expr. */
1276 spec_entry elt;
1284 else
1293 }
1295 /* Like retrieve_specialization, but for local declarations. */
1297 tree
1299 {
1305 }
1307 /* Returns nonzero iff DECL is a specialization of TMPL. */
1309 int
1311 {
1312 tree t;
1315 {
1321 }
1322 else
1323 {
1332 }
1335 }
1337 /* Returns nonzero iff DECL is a specialization of friend declaration
1338 FRIEND_DECL according to [temp.friend]. */
1340 bool
1342 {
1349 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1350 of a template class, we want to check if DECL is a specialization
1351 if this. */
1356 {
1357 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1360 }
1365 /* There is nothing to do if this is not a template friend. */
1372 /* [temp.friend/6]
1373 A member of a class template may be declared to be a friend of a
1374 non-template class. In this case, the corresponding member of
1375 every specialization of the class template is a friend of the
1376 class granting friendship.
1378 For example, given a template friend declaration
1380 template <class T> friend void A<T>::f();
1382 the member function below is considered a friend
1384 template <> struct A<int> {
1385 void f();
1386 };
1388 For this type of template friend, TEMPLATE_DEPTH below will be
1389 nonzero. To determine if DECL is a friend of FRIEND, we first
1390 check if the enclosing class is a specialization of another. */
1397 {
1398 /* Next, we check the members themselves. In order to handle
1399 a few tricky cases, such as when FRIEND_DECL's are
1401 template <class T> friend void A<T>::g(T t);
1402 template <class T> template <T t> friend void A<T>::h();
1404 and DECL's are
1406 void A<int>::g(int);
1407 template <int> void A<int>::h();
1409 we need to figure out ARGS, the template arguments from
1410 the context of DECL. This is required for template substitution
1411 of `T' in the function parameter of `g' and template parameter
1412 of `h' in the above examples. Here ARGS corresponds to `int'. */
1419 {
1421 {
1424 else
1426 current_depth++;
1427 }
1429 }
1432 {
1434 tree friend_type;
1435 tree decl_type;
1436 tree friend_args_type;
1437 tree decl_args_type;
1439 /* Make sure that both DECL and FRIEND_DECL are templates or
1440 non-templates. */
1446 {
1447 /* If both are templates, check template parameter list. */
1448 tree friend_parms
1453 friend_parms))
1457 }
1458 else
1466 /* Check if return types match. */
1470 /* Check if function parameter types match, ignoring the
1471 `this' parameter. */
1480 }
1481 else
1482 {
1483 /* DECL is a TYPE_DECL */
1487 /* Make sure that both DECL and FRIEND_DECL are templates or
1488 non-templates. */
1489 is_template
1496 {
1497 tree friend_parms;
1498 /* If both are templates, check the name of the two
1499 TEMPLATE_DECL's first because is_friend didn't. */
1504 /* Now check template parameter list. */
1505 friend_parms
1508 return comp_template_parms
1510 friend_parms);
1511 }
1512 else
1515 }
1516 }
1518 }
1520 /* Register the specialization SPEC as a specialization of TMPL with
1521 the indicated ARGS. IS_FRIEND indicates whether the specialization
1522 is actually just a friend declaration. ATTRLIST is the list of
1523 attributes that the specialization is declared with or NULL when
1524 it isn't. Returns SPEC, or an equivalent prior declaration, if
1525 available.
1527 We also store instantiations of field packs in the hash table, even
1528 though they are not themselves templates, to make lookup easier. */
1530 static tree
1532 hashval_t hash)
1533 {
1534 tree fn;
1540 spec_entry elt;
1551 else
1554 /* We can sometimes try to re-register a specialization that we've
1555 already got. In particular, regenerate_decl_from_template calls
1556 duplicate_decls which will update the specialization list. But,
1557 we'll still get called again here anyhow. It's more convenient
1558 to simply allow this than to try to prevent it. */
1562 {
1564 {
1567 {
1569 fn);
1571 }
1572 else
1573 {
1574 tree clone;
1575 /* This situation should occur only if the first
1576 specialization is an implicit instantiation, the
1577 second is an explicit specialization, and the
1578 implicit instantiation has not yet been used. That
1579 situation can occur if we have implicitly
1580 instantiated a member function and then specialized
1581 it later.
1583 We can also wind up here if a friend declaration that
1584 looked like an instantiation turns out to be a
1585 specialization:
1587 template <class T> void foo(T);
1588 class S { friend void foo<>(int) };
1589 template <> void foo(int);
1591 We transform the existing DECL in place so that any
1592 pointers to it become pointers to the updated
1593 declaration.
1595 If there was a definition for the template, but not
1596 for the specialization, we want this to look as if
1597 there were no definition, and vice versa. */
1601 /* The call to duplicate_decls will have applied
1602 [temp.expl.spec]:
1604 An explicit specialization of a function template
1605 is inline only if it is explicitly declared to be,
1606 and independently of whether its function template
1607 is.
1609 to the primary function; now copy the inline bits to
1610 the various clones. */
1612 {
1619 }
1623 }
1624 }
1626 {
1629 /* We've already complained in duplicate_decls. */
1633 /* Dup decl failed, but this is a new definition. Set the
1634 line number so any errors match this new
1635 definition. */
1639 }
1640 }
1644 /* A specialization must be declared in the same namespace as the
1645 template it is specializing. */
1658 /* If TMPL is a forward declaration of a template function, keep a list
1659 of all specializations in case we need to reassign them to a friend
1660 template later in tsubst_friend_function.
1662 Also keep a list of all variable template instantiations so that
1663 process_partial_specialization can check whether a later partial
1664 specialization would have used it. */
1669 }
1671 /* Restricts tree and type comparisons. */
1675 /* Whether we are comparing template arguments during partial ordering
1676 (and therefore want the comparison to look through dependent alias
1677 template specializations). */
1681 /* Returns true iff two spec_entry nodes are equivalent. */
1683 bool
1685 {
1694 /* tmpl could be a FIELD_DECL for a capture pack. */
1698 {
1699 /* Partial specializations of a variable template can be distinguished by
1700 constraints. */
1704 }
1710 }
1712 /* Returns a hash for a template TMPL and template arguments ARGS. */
1714 static hashval_t
1716 {
1719 }
1721 hashval_t
1723 {
1728 }
1730 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1731 ignoring SPEC. */
1733 hashval_t
1735 {
1737 }
1739 /* Recursively calculate a hash value for a template argument ARG, for use
1740 in the hash tables of template specializations. We must be
1741 careful to (at least) skip the same entities template_args_equal
1742 does. */
1744 hashval_t
1746 {
1751 /* Strip nop-like things, but not the same as STRIP_NOPS. */
1762 {
1764 /* Getting here with an ARGUMENT_PACK_SELECT means we're probably
1765 preserving it in a hash table, which is bad because it will change
1766 meaning when gen_elem_of_pack_expansion_instantiation changes the
1767 ARGUMENT_PACK_SELECT_INDEX. */
1801 {
1804 {
1807 }
1809 }
1813 {
1816 }
1827 val = iterative_hash_template_arg
1839 val);
1841 val);
1850 /* [temp.over.link] Two lambda-expressions are never considered
1851 equivalent.
1853 So just hash the closure type. */
1864 /* Now hash operands as usual. */
1868 {
1871 {
1875 }
1877 call_expr_arg_iterator ai;
1882 }
1886 }
1890 {
1893 {
1894 // We want an alias specialization that survived strip_typedefs
1895 // to hash differently from its TYPE_CANONICAL, to avoid hash
1896 // collisions that compare as different in template_args_equal.
1897 // These could be dependent specializations that strip_typedefs
1898 // left alone, or untouched specializations because
1899 // coerce_template_parms returns the unconverted template
1900 // arguments if it sees incomplete argument packs.
1903 }
1906 {
1913 {
1914 /* Hash the components that are relevant to TYPENAME_TYPE
1915 equivalence as determined by structural_comptypes. We
1916 can only coherently do this when comparing_specializations
1917 is set, because otherwise structural_comptypes tries
1918 resolving TYPENAME_TYPE via the current instantiation. */
1923 }
1930 {
1933 }
1935 }
1948 }
1949 }
1951 /* Unregister the specialization SPEC as a specialization of TMPL.
1952 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1953 if the SPEC was listed as a specialization of TMPL.
1955 Note that SPEC has been ggc_freed, so we can't look inside it. */
1957 bool
1959 {
1961 spec_entry elt;
1969 {
1974 }
1977 }
1979 /* Like register_specialization, but for local declarations. We are
1980 registering SPEC, an instantiation of TMPL. */
1982 void
1984 {
1987 }
1989 /* Registers T as a specialization of itself. This is used to preserve
1990 the references to already-parsed parameters when instantiating
1991 postconditions. */
1993 void
1995 {
1997 }
1999 /* TYPE is a class type. Returns true if TYPE is an explicitly
2000 specialized class. */
2002 bool
2004 {
2008 }
2010 /* Print the list of functions at FNS, going through all the overloads
2011 for each element of the list. Alternatively, FNS cannot be a
2012 TREE_LIST, in which case it will be printed together with all the
2013 overloads.
2015 MORE and *STR should respectively be FALSE and NULL when the function
2016 is called from the outside. They are used internally on recursive
2017 calls. print_candidates manages the two parameters and leaves NULL
2018 in *STR when it ends. */
2020 static void
2022 {
2026 else
2028 {
2034 {
2037 else
2040 }
2042 }
2043 }
2045 /* Print the list of candidate FNS in an error message. FNS can also
2046 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
2048 void
2050 {
2054 }
2056 /* Get a (possibly) constrained template declaration for the
2057 purpose of ordering candidates. */
2058 static tree
2060 {
2066 }
2068 /* Among candidates having the same signature, return the
2069 most constrained or NULL_TREE if there is no best candidate.
2070 If the signatures of candidates vary (e.g., template
2071 specialization vs. member function), then there can be no
2072 most constrained.
2074 Note that we don't compare constraints on the functions
2075 themselves, but rather those of their templates. */
2076 static tree
2078 {
2079 // Try to find the best candidate in a first pass.
2082 {
2089 }
2091 // Verify that the champ is better than previous candidates.
2096 }
2099 }
2102 /* Returns the template (one of the functions given by TEMPLATE_ID)
2103 which can be specialized to match the indicated DECL with the
2104 explicit template args given in TEMPLATE_ID. The DECL may be
2105 NULL_TREE if none is available. In that case, the functions in
2106 TEMPLATE_ID are non-members.
2108 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2109 specialization of a member template.
2111 The TEMPLATE_COUNT is the number of references to qualifying
2112 template classes that appeared in the name of the function. See
2113 check_explicit_specialization for a more accurate description.
2115 TSK indicates what kind of template declaration (if any) is being
2116 declared. TSK_TEMPLATE indicates that the declaration given by
2117 DECL, though a FUNCTION_DECL, has template parameters, and is
2118 therefore a template function.
2120 The template args (those explicitly specified and those deduced)
2121 are output in a newly created vector *TARGS_OUT.
2123 If it is impossible to determine the result, an error message is
2124 issued. The error_mark_node is returned to indicate failure. */
2126 static tree
2128 tree decl,
2132 tmpl_spec_kind tsk)
2133 {
2134 tree fns;
2135 tree targs;
2136 tree explicit_targs;
2139 /* A TREE_LIST of templates of which DECL may be a specialization.
2140 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2141 corresponding TREE_PURPOSE is the set of template arguments that,
2142 when used to instantiate the template, would produce a function
2143 with the signature of DECL. */
2153 /* We shouldn't be specializing a member template of an
2154 unspecialized class template; we already gave an error in
2155 check_specialization_scope, now avoid crashing. */
2159 {
2162 }
2170 /* Check for baselinks. */
2175 {
2179 }
2181 {
2184 }
2186 /* Count the number of template headers specified for this
2187 specialization. */
2198 {
2201 tf_warning_or_error);
2205 }
2207 {
2211 {
2212 tree decl_arg_types;
2213 tree fn_arg_types;
2215 /* In case of explicit specialization, we need to check if
2216 the number of template headers appearing in the specialization
2217 is correct. This is usually done in check_explicit_specialization,
2218 but the check done there cannot be exhaustive when specializing
2219 member functions. Consider the following code:
2221 template <> void A<int>::f(int);
2222 template <> template <> void A<int>::f(int);
2224 Assuming that A<int> is not itself an explicit specialization
2225 already, the first line specializes "f" which is a non-template
2226 member function, whilst the second line specializes "f" which
2227 is a template member function. So both lines are syntactically
2228 correct, and check_explicit_specialization does not reject
2229 them.
2231 Here, we can do better, as we are matching the specialization
2232 against the declarations. We count the number of template
2233 headers, and we check if they match TEMPLATE_COUNT + 1
2234 (TEMPLATE_COUNT is the number of qualifying template classes,
2235 plus there must be another header for the member template
2236 itself).
2238 Notice that if header_count is zero, this is not a
2239 specialization but rather a template instantiation, so there
2240 is no check we can perform here. */
2242 {
2245 }
2247 /* Check that the number of template arguments at the
2248 innermost level for DECL is the same as for FN. */
2256 /* DECL might be a specialization of FN. */
2260 /* For a non-static member function, we need to make sure
2261 that the const qualification is the same. Since
2262 get_bindings does not try to merge the "this" parameter,
2263 we must do the comparison explicitly. */
2265 {
2270 /* And the ref-qualification. */
2274 }
2276 /* Skip the "this" parameter and, for constructors of
2277 classes with virtual bases, the VTT parameter. A
2278 full specialization of a constructor will have a VTT
2279 parameter, but a template never will. */
2280 decl_arg_types
2282 fn_arg_types
2285 /* Function templates cannot be specializations; there are
2286 no partial specializations of functions. Therefore, if
2287 the type of DECL does not match FN, there is no
2288 match.
2290 Note that it should never be the case that we have both
2291 candidates added here, and for regular member functions
2292 below. */
2294 {
2296 current_template_parms))
2309 {
2310 /* C++20 CA104: Substitute directly into the
2311 constraint-expression. */
2317 }
2321 }
2323 /* See whether this function might be a specialization of this
2324 template. Suppress access control because we might be trying
2325 to make this specialization a friend, and we have already done
2326 access control for the declaration of the specialization. */
2332 /* We cannot deduce template arguments that when used to
2333 specialize TMPL will produce DECL. */
2337 /* We deduced something involving 'auto', which isn't a valid
2338 template argument. */
2341 /* Save this template, and the arguments deduced. */
2343 }
2345 /* FN is an ordinary member function, and we need a
2346 specialization of a member template. */
2347 ;
2349 /* We can get IDENTIFIER_NODEs here in certain erroneous
2350 cases. */
2351 ;
2353 /* This is just an ordinary non-member function. Nothing can
2354 be a specialization of that. */
2355 ;
2357 /* Cannot specialize functions that are created implicitly. */
2358 ;
2359 else
2360 {
2361 tree decl_arg_types;
2363 /* This is an ordinary member function. However, since
2364 we're here, we can assume its enclosing class is a
2365 template class. For example,
2367 template <typename T> struct S { void f(); };
2368 template <> void S<int>::f() {}
2370 Here, S<int>::f is a non-template, but S<int> is a
2371 template class. If FN has the same type as DECL, we
2372 might be in business. */
2375 /* Its enclosing class is an explicit specialization
2376 of a template class. This is not a candidate. */
2381 /* The return types differ. */
2384 /* Adjust the type of DECL in case FN is a static member. */
2391 decl_arg_types))
2399 // If the deduced arguments do not satisfy the constraints,
2400 // this is not a candidate.
2404 // Add the candidate.
2406 }
2407 }
2410 {
2411 /* We have:
2413 [temp.expl.spec]
2415 It is possible for a specialization with a given function
2416 signature to be instantiated from more than one function
2417 template. In such cases, explicit specification of the
2418 template arguments must be used to uniquely identify the
2419 function template specialization being specialized.
2421 Note that here, there's no suggestion that we're supposed to
2422 determine which of the candidate templates is most
2423 specialized. However, we, also have:
2425 [temp.func.order]
2427 Partial ordering of overloaded function template
2428 declarations is used in the following contexts to select
2429 the function template to which a function template
2430 specialization refers:
2432 -- when an explicit specialization refers to a function
2433 template.
2435 So, we do use the partial ordering rules, at least for now.
2436 This extension can only serve to make invalid programs valid,
2437 so it's safe. And, there is strong anecdotal evidence that
2438 the committee intended the partial ordering rules to apply;
2439 the EDG front end has that behavior, and John Spicer claims
2440 that the committee simply forgot to delete the wording in
2441 [temp.expl.spec]. */
2444 {
2447 }
2448 }
2450 // Concepts allows multiple declarations of member functions
2451 // with the same signature. Like above, we need to rely on
2452 // on the partial ordering of those candidates to determine which
2453 // is the best.
2455 {
2457 {
2460 }
2461 }
2464 {
2469 "saw %d %<template<>%>, need %d for "
2474 }
2478 {
2484 }
2486 /* We have one, and exactly one, match. */
2488 {
2492 /* Propagate the candidate's constraints to the declaration. */
2496 /* DECL is a re-declaration or partial instantiation of a template
2497 function. */
2500 /* It was a specialization of an ordinary member function in a
2501 template class. */
2503 }
2505 /* It was a specialization of a template. */
2509 /* Propagate the template's constraints to the declaration. */
2514 }
2516 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2517 but with the default argument values filled in from those in the
2518 TMPL_TYPES. */
2520 static tree
2522 tree tmpl_types)
2523 {
2524 tree new_spec_types;
2532 /* Substitute into the rest of the list. */
2533 new_spec_types =
2537 /* Add the default argument for this parameter. */
2540 new_spec_types);
2541 }
2543 /* DECL is an explicit specialization. Replicate default arguments
2544 from the template it specializes. (That way, code like:
2546 template <class T> void f(T = 3);
2547 template <> void f(double);
2548 void g () { f (); }
2550 works, as required.) An alternative approach would be to look up
2551 the correct default arguments at the call-site, but this approach
2552 is consistent with how implicit instantiations are handled. */
2554 static void
2556 {
2557 tree tmpl;
2558 tree spec_types;
2559 tree tmpl_types;
2560 tree new_spec_types;
2561 tree old_type;
2562 tree new_type;
2563 tree t;
2568 /* See if there's anything we need to do. */
2581 {
2582 /* Remove the this pointer, but remember the object's type for
2583 CV quals. */
2589 {
2590 /* DECL may contain more parameters than TMPL due to the extra
2591 in-charge parameter in constructors and destructors. */
2594 }
2596 {
2599 }
2600 }
2602 /* Compute the merged default arguments. */
2603 new_spec_types =
2606 /* Compute the new FUNCTION_TYPE. */
2608 {
2612 new_spec_types);
2615 /* Put the in-charge parameter back. */
2618 new_spec_types);
2622 new_spec_types);
2623 }
2624 else
2626 new_spec_types);
2632 }
2634 /* Return the number of template headers we expect to see for a definition
2635 or specialization of CTYPE or one of its non-template members. */
2637 int
2639 {
2643 {
2644 /* You're supposed to have one `template <...>' for every
2645 template class, but you don't need one for a full
2646 specialization. For example:
2648 template <class T> struct S{};
2649 template <> struct S<int> { void f(); };
2650 void S<int>::f () {}
2652 is correct; there shouldn't be a `template <>' for the
2653 definition of `S<int>::f'. */
2655 /* If CTYPE does not have template information of any
2656 kind, then it is not a template, nor is it nested
2657 within a template. */
2665 }
2668 }
2670 /* Do a simple sanity check on the template headers that precede the
2671 variable declaration DECL. */
2673 void
2675 {
2680 {
2683 "variable templates only available with "
2686 // Namespace-scope variable templates should have a template header.
2688 }
2690 {
2691 auto_diagnostic_group d;
2693 "too many template headers for %qD "
2699 "members of an explicitly specialized class are defined "
2701 }
2702 }
2704 /* An explicit specialization whose declarator-id or class-head-name is not
2705 qualified shall be declared in the nearest enclosing namespace of the
2706 template, or, if the namespace is inline (7.3.1), any namespace from its
2707 enclosing namespace set.
2709 If the name declared in the explicit instantiation is an unqualified name,
2710 the explicit instantiation shall appear in the namespace where its template
2711 is declared or, if that namespace is inline (7.3.1), any namespace from its
2712 enclosing namespace set. */
2714 void
2716 {
2721 {
2727 /* This was allowed in C++98, so only pedwarn. */
2729 "outside its namespace must use a nested-name-"
2731 }
2732 }
2734 /* Warn for a template specialization SPEC that is missing some of a set
2735 of function or type attributes that the template TEMPL is declared with.
2736 ATTRLIST is a list of additional attributes that SPEC should be taken
2737 to ultimately be declared with. */
2739 static void
2741 {
2745 /* Avoid warning if the difference between the primary and
2746 the specialization is not in one of the attributes below. */
2750 };
2752 /* Put together a list of the black listed attributes that the primary
2753 template is declared with that the specialization is not, in case
2754 it's not apparent from the most recent declaration of the primary. */
2755 pretty_printer str;
2762 auto_diagnostic_group d;
2765 spec))
2771 }
2773 /* Check to see if the function just declared, as indicated in
2774 DECLARATOR, and in DECL, is a specialization of a function
2775 template. We may also discover that the declaration is an explicit
2776 instantiation at this point.
2778 Returns DECL, or an equivalent declaration that should be used
2779 instead if all goes well. Issues an error message if something is
2780 amiss. Returns error_mark_node if the error is not easily
2781 recoverable.
2783 FLAGS is a bitmask consisting of the following flags:
2785 2: The function has a definition.
2786 4: The function is a friend.
2788 The TEMPLATE_COUNT is the number of references to qualifying
2789 template classes that appeared in the name of the function. For
2790 example, in
2792 template <class T> struct S { void f(); };
2793 void S<int>::f();
2795 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2796 classes are not counted in the TEMPLATE_COUNT, so that in
2798 template <class T> struct S {};
2799 template <> struct S<int> { void f(); }
2800 template <> void S<int>::f();
2802 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2803 invalid; there should be no template <>.)
2805 If the function is a specialization, it is marked as such via
2806 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2807 is set up correctly, and it is added to the list of specializations
2808 for that template. */
2810 tree
2812 tree decl,
2815 tree attrlist)
2816 {
2825 tmpl_spec_kind tsk;
2828 {
2831 else
2833 }
2834 else
2838 {
2841 {
2844 }
2848 {
2850 /* This could be something like:
2852 template <class T> void f(T);
2853 class S { friend void f<>(int); } */
2855 else
2856 {
2857 /* This case handles bogus declarations like template <>
2858 template <class T> void f<int>(); */
2862 declarator);
2864 }
2865 }
2869 /* The error has already been reported in
2870 check_specialization_scope. */
2876 /* Fall through. */
2889 decl);
2892 else
2896 /* Fall through. */
2902 /* In cases like template<> constexpr bool v = true;
2903 We'll give an error in check_template_variable. */
2909 else
2915 {
2916 /* This case handles bogus declarations like template <>
2917 template <class T> void f<int>(); */
2922 declarator);
2924 {
2925 /* Partial specialization of variable template. */
2929 }
2932 "non-type partial specialization %qE "
2934 else
2936 "non-class, non-variable partial specialization %qE "
2939 ok:;
2940 }
2943 /* This is a specialization of a member template, without
2944 specialization the containing class. Something like:
2946 template <class T> struct S {
2947 template <class U> void f (U);
2948 };
2949 template <> template <class U> void S<int>::f(U) {}
2951 That's a specialization -- but of the entire template. */
2957 }
2960 /* This doesn't apply to variable templates. */
2962 {
2966 {
2970 }
2971 }
2974 {
2980 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2982 {
2983 tree fns;
2988 else
2989 {
2990 /* If there is no class context, the explicit instantiation
2991 must be at namespace scope. */
2994 /* Find the namespace binding, using the declaration
2995 context. */
2999 {
3000 /* If lookup fails, look for a friend declaration so we can
3001 give a better diagnostic. */
3002 fns = (lookup_qualified_name
3007 }
3010 {
3013 }
3014 }
3017 }
3023 {
3025 /* A specialization in class scope. This is invalid,
3026 but the error will already have been flagged by
3027 check_specialization_scope. */
3029 else
3030 {
3031 /* It's not valid to write an explicit instantiation in
3032 class scope, e.g.:
3034 class C { template void f(); }
3036 This case is caught by the parser. However, on
3037 something like:
3039 template class C { void f(); };
3041 (which is invalid) we can get here. The error will be
3042 issued later. */
3043 ;
3044 }
3047 }
3050 {
3051 // We'll match variable templates in start_decl.
3055 /* Find the list of functions in ctype that have the same
3056 name as the declared function. */
3060 {
3064 {
3065 /* From [temp.expl.spec]:
3067 If such an explicit specialization for the member
3068 of a class template names an implicitly-declared
3069 special member function (clause _special_), the
3070 program is ill-formed.
3072 Similar language is found in [temp.explicit]. */
3075 }
3078 }
3080 /* For a type-conversion operator, We might be looking for
3081 `operator int' which will be a specialization of
3082 `operator T'. Grab all the conversion operators, and
3083 then select from them. */
3088 {
3091 }
3092 else
3094 }
3096 /* Figure out what exactly is being specialized at this point.
3097 Note that for an explicit instantiation, even one for a
3098 member function, we cannot tell a priori whether the
3099 instantiation is for a member template, or just a member
3100 function of a template class. Even if a member template is
3101 being instantiated, the member template arguments may be
3102 elided if they can be deduced from the rest of the
3103 declaration. */
3106 member_specialization,
3107 template_count,
3108 tsk);
3111 /* We couldn't figure out what this declaration was
3112 specializing. */
3114 else
3115 {
3117 {
3118 auto_diagnostic_group d;
3120 "friend declaration %qD is not visible to "
3124 }
3133 {
3134 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3135 is done by do_decl_instantiation later. */
3141 {
3142 /* If TMPL is not the most general template (for
3143 example, if TMPL is a friend template that is
3144 injected into namespace scope), then there will
3145 be too many levels of TARGS. Remove some of them
3146 here. */
3148 tree new_targs;
3155 }
3158 }
3160 /* If we thought that the DECL was a member function, but it
3161 turns out to be specializing a static member function,
3162 make DECL a static member function as well. */
3168 /* If this is a specialization of a member template of a
3169 template class, we want to return the TEMPLATE_DECL, not
3170 the specialization of it. */
3172 {
3177 {
3178 tree parm;
3182 /* We want to use the argument list specified in the
3183 definition, not in the original declaration. */
3188 }
3193 }
3195 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3201 /* Inherit default function arguments from the template
3202 DECL is specializing. */
3206 /* This specialization has the same protection as the
3207 template it specializes. */
3211 /* 7.1.1-1 [dcl.stc]
3213 A storage-class-specifier shall not be specified in an
3214 explicit specialization...
3216 The parser rejects these, so unless action is taken here,
3217 explicit function specializations will always appear with
3218 global linkage.
3220 The action recommended by the C++ CWG in response to C++
3221 defect report 605 is to make the storage class and linkage
3222 of the explicit specialization match the templated function:
3224 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3225 */
3227 {
3231 /* A concept cannot be specialized. */
3233 {
3235 gen_tmpl);
3237 }
3239 /* This specialization has the same linkage and visibility as
3240 the function template it specializes. */
3243 {
3246 }
3249 {
3252 }
3253 }
3255 /* If DECL is a friend declaration, declared using an
3256 unqualified name, the namespace associated with DECL may
3257 have been set incorrectly. For example, in:
3259 template <typename T> void f(T);
3260 namespace N {
3261 struct S { friend void f<int>(int); }
3262 }
3264 we will have set the DECL_CONTEXT for the friend
3265 declaration to N, rather than to the global namespace. */
3270 /* This is not really a declaration of a specialization.
3271 It's just the name of an instantiation. But, it's not
3272 a request for an instantiation, either. */
3275 /* A specialization is not necessarily COMDAT. */
3281 /* If this is a full specialization, register it so that we can find
3282 it again. Partial specializations will be registered in
3283 process_partial_specialization. */
3285 {
3290 }
3292 /* If this is a specialization, splice any contracts that may have
3293 been inherited from the template, removing them. */
3297 /* A 'structor should already have clones. */
3303 }
3304 }
3307 }
3309 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3310 parameters. These are represented in the same format used for
3311 DECL_TEMPLATE_PARMS. */
3313 int
3315 {
3330 {
3334 /* If either of the template parameters are invalid, assume
3335 they match for the sake of error recovery. */
3348 }
3351 }
3353 /* Returns true if two template parameters are declared with
3354 equivalent constraints. */
3356 static bool
3358 {
3366 }
3368 /* Returns true when two template parameters are equivalent. */
3370 static bool
3372 {
3376 /* If either of the template parameters are invalid, assume
3377 they match for the sake of error recovery. */
3381 /* ... they declare parameters of the same kind. */
3385 /* ... one parameter was introduced by a parameter declaration, then
3386 both are. This case arises as a result of eagerly rewriting declarations
3387 during parsing. */
3392 /* ... if either declares a pack, they both do. */
3397 {
3398 /* ... if they declare non-type parameters, the types are equivalent. */
3401 }
3403 {
3404 /* ... if they declare template template parameters, their template
3405 parameter lists are equivalent. */
3408 }
3410 /* ... if they are declared with a qualified-concept name, they both
3411 are, and those names are equivalent. */
3413 }
3415 /* Returns true if two template parameters lists are equivalent.
3416 Two template parameter lists are equivalent if they have the
3417 same length and their corresponding parameters are equivalent.
3419 PARMS1 and PARMS2 are TREE_LISTs containing TREE_VECs: the
3420 data structure returned by DECL_TEMPLATE_PARMS.
3422 This is generally the same implementation as comp_template_parms
3423 except that it also the concept names and arguments used to
3424 introduce parameters. */
3426 static bool
3428 {
3439 {
3444 }
3447 }
3449 /* Return true if the requires-clause of the template parameter lists are
3450 equivalent and false otherwise. */
3451 static bool
3453 {
3461 }
3463 /* Returns true if two template heads are equivalent. 17.6.6.1p6:
3464 Two template heads are equivalent if their template parameter
3465 lists are equivalent and their requires clauses are equivalent.
3467 In pre-C++20, this is equivalent to calling comp_template_parms
3468 for the template parameters of TMPL1 and TMPL2. */
3470 bool
3472 {
3476 /* Don't change the matching rules for pre-C++20. */
3480 /* ... have the same number of template parameters, and their
3481 corresponding parameters are equivalent. */
3485 /* ... if either has a requires-clause, they both do and their
3486 corresponding constraint-expressions are equivalent. */
3488 }
3490 /* Determine whether PARM is a parameter pack. */
3492 bool
3494 {
3495 /* Determine if we have a non-type template parameter pack. */
3502 /* If this is a list of template parameters, we could get a
3503 TYPE_DECL or a TEMPLATE_DECL. */
3507 /* Otherwise it must be a type template parameter. */
3511 }
3513 /* Determine if T is a function parameter pack. */
3515 bool
3517 {
3521 }
3523 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3524 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3526 tree
3528 {
3535 }
3537 /* Return true iff the function parameter PARAM_DECL was expanded
3538 from the function parameter pack PACK. */
3540 bool
3542 {
3547 /* The parameter pack and its pack arguments have the same
3548 DECL_PARM_INDEX. */
3550 }
3552 /* Determine whether ARGS describes a variadic template args list,
3553 i.e., one that is terminated by a template argument pack. */
3555 static bool
3557 {
3559 tree last_parm;
3573 }
3575 /* Generate a new name for the parameter pack name NAME (an
3576 IDENTIFIER_NODE) that incorporates its */
3578 static tree
3580 {
3581 /* Munge the name to include the parameter index. */
3582 #define NUMBUF_LEN 128
3596 }
3598 /* Return true if T is a primary function, class or alias template
3599 specialization, not including the template pattern. */
3601 bool
3603 {
3619 }
3621 /* Return true if PARM is a template template parameter. */
3623 bool
3625 {
3627 }
3629 /* Return true iff PARM is a DECL representing a type template
3630 parameter. */
3632 bool
3634 {
3639 }
3641 /* Return the template parameters of T if T is a
3642 primary template instantiation, NULL otherwise. */
3644 tree
3646 {
3651 parms = INNERMOST_TEMPLATE_PARMS
3655 }
3657 /* Returns the template arguments of T if T is a template instantiation,
3658 NULL otherwise. */
3660 tree
3662 {
3670 }
3672 /* Return the argument pack elements of T if T is a template argument pack,
3673 NULL otherwise. */
3675 tree
3677 {
3683 }
3685 /* In an ARGUMENT_PACK_SELECT, the actual underlying argument that the
3686 ARGUMENT_PACK_SELECT represents. */
3688 static tree
3690 {
3694 /* If the selected argument is an expansion E, that most likely means we were
3695 called from gen_elem_of_pack_expansion_instantiation during the
3696 substituting of an argument pack (of which the Ith element is a pack
3697 expansion, where I is ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
3698 In this case, the Ith element resulting from this substituting is going to
3699 be a pack expansion, which pattern is the pattern of E. Let's return the
3700 pattern of E, and gen_elem_of_pack_expansion_instantiation will build the
3701 resulting pack expansion from it. */
3703 {
3704 /* Make sure we aren't throwing away arg info. */
3707 }
3710 }
3712 /* Return a modification of ARGS that's suitable for preserving inside a hash
3713 table. In particular, this replaces each ARGUMENT_PACK_SELECT with its
3714 underlying argument. ARGS is copied (upon modification) iff COW_P. */
3716 static tree
3718 {
3723 {
3725 tree r;
3732 else
3735 {
3737 {
3740 }
3742 }
3743 }
3746 }
3748 /* True iff FN is a function representing a built-in variadic parameter
3749 pack. */
3751 bool
3753 {
3763 }
3765 /* True iff CALL is a call to a function representing a built-in variadic
3766 parameter pack. */
3768 static bool
3770 {
3774 }
3776 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3778 static tree
3780 tree in_decl)
3781 {
3786 {
3788 {
3791 }
3796 }
3797 else
3798 {
3803 /* Calculate the largest value of len that won't make the size of the vec
3804 overflow an int. The compiler will exceed resource limits long before
3805 this, but it seems a decent place to diagnose. */
3809 {
3813 max);
3815 }
3823 }
3824 }
3826 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3827 CALL. */
3829 static tree
3831 tree in_decl)
3832 {
3842 }
3844 /* Return true if the tree T has the extra args mechanism for
3845 avoiding partial instantiation. */
3847 static bool
3849 {
3854 }
3856 /* Structure used to track the progress of find_parameter_packs_r. */
3857 struct find_parameter_pack_data
3858 {
3859 /* TREE_LIST that will contain all of the parameter packs found by
3860 the traversal. */
3863 /* Set of AST nodes that have been visited by the traversal. */
3866 /* True iff we're making a type pack expansion. */
3869 /* True iff we found a subtree that has the extra args mechanism. */
3871 };
3873 /* Identifies all of the argument packs that occur in a template
3874 argument and appends them to the TREE_LIST inside DATA, which is a
3875 find_parameter_pack_data structure. This is a subroutine of
3876 make_pack_expansion and uses_parameter_packs. */
3877 static tree
3879 {
3885 #define WALK_SUBTREE(NODE) \
3886 cp_walk_tree (&(NODE), &find_parameter_packs_r, \
3887 ppd, ppd->visited) \
3889 /* Don't look through typedefs; we are interested in whether a
3890 parameter pack is actually written in the expression/type we're
3891 looking at, not the target type. */
3893 {
3894 /* But do look at arguments for an alias template. */
3901 }
3903 /* Identify whether this is a parameter pack or not. */
3905 {
3913 /* FALLTHRU */
3915 /* If the placeholder appears in the decl-specifier-seq of a function
3916 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3917 is a pack expansion, the invented template parameter is a template
3918 parameter pack. */
3928 {
3929 /* We don't want to walk into the type of a PARM_DECL,
3930 because we don't want to see the type parameter pack. */
3933 }
3938 {
3939 /* We don't want to walk into the type of a variadic capture proxy,
3940 because we don't want to see the type parameter pack. */
3943 }
3945 {
3947 find_parameter_packs_r,
3950 }
3962 /* Not a parameter pack. */
3964 }
3967 {
3968 /* Add this parameter pack to the list. */
3970 }
3979 /* This switch statement will return immediately if we don't find a
3980 parameter pack. ??? Should some of these be in cp_walk_subtrees? */
3982 {
3984 /* Check the template itself. */
3990 {
3992 /* Ignore the declaration of a capture proxy for a parameter pack. */
3996 /* Since we stop at typedefs above, we need to look through them at
3997 the point of the DECL_EXPR. */
4001 }
4028 {
4029 /* Since we defer implicit capture, look in the parms and body. */
4036 }
4039 {
4040 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
4041 type_pack_expansion_p to false so that any placeholders
4042 within the expression don't get marked as parameter packs. */
4050 }
4059 /* Don't walk into IF_STMT_EXTRA_ARGS. */
4066 {
4067 /* Local class, need to look through the whole definition.
4068 TYPE_BINFO might be unset for a partial instantiation. */
4073 }
4074 else
4075 /* Enum, look at the values. */
4089 }
4091 #undef WALK_SUBTREE
4094 }
4096 /* Determines if the expression or type T uses any parameter packs. */
4097 tree
4099 {
4108 }
4110 /* Turn ARG, which may be an expression, type, or a TREE_LIST
4111 representation a base-class initializer into a parameter pack
4112 expansion. If all goes well, the resulting node will be an
4113 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
4114 respectively. */
4115 tree
4117 {
4118 tree result;
4127 {
4128 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
4129 class initializer. In this case, the TREE_PURPOSE will be a
4130 _TYPE node (representing the base class expansion we're
4131 initializing) and the TREE_VALUE will be a TREE_LIST
4132 containing the initialization arguments.
4134 The resulting expansion looks somewhat different from most
4135 expansions. Rather than returning just one _EXPANSION, we
4136 return a TREE_LIST whose TREE_PURPOSE is a
4137 TYPE_PACK_EXPANSION containing the bases that will be
4138 initialized. The TREE_VALUE will be identical to the
4139 original TREE_VALUE, which is a list of arguments that will
4140 be passed to each base. We do not introduce any new pack
4141 expansion nodes into the TREE_VALUE (although it is possible
4142 that some already exist), because the TREE_PURPOSE and
4143 TREE_VALUE all need to be expanded together with the same
4144 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
4145 resulting TREE_PURPOSE will mention the parameter packs in
4146 both the bases and the arguments to the bases. */
4147 tree purpose;
4148 tree value;
4151 /* Determine which parameter packs will be used by the base
4152 class expansion. */
4161 {
4164 arg);
4167 }
4170 {
4171 /* Collect the sets of parameter packs used in each of the
4172 initialization arguments. */
4174 {
4175 /* Determine which parameter packs will be expanded in this
4176 argument. */
4179 }
4180 }
4184 /* Create the pack expansion type for the base type. */
4190 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4191 they will rarely be compared to anything. */
4195 }
4200 /* Build the PACK_EXPANSION_* node. */
4201 result = for_types
4206 {
4207 /* Propagate type and const-expression information. */
4210 /* Mark this read now, since the expansion might be length 0. */
4212 }
4213 else
4214 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4215 they will rarely be compared to anything. */
4218 /* Determine which parameter packs will be expanded. */
4225 /* Make sure we found some parameter packs. */
4227 {
4229 {
4232 else
4234 }
4236 }
4241 /* If the pattern of this pack expansion contains a subtree that has
4242 the extra args mechanism for avoiding partial instantiation, then
4243 force this pack expansion to also use extra args. Otherwise
4244 partial instantiation of this pack expansion may not lower the
4245 level of some parameter packs within the pattern, which would
4246 confuse tsubst_pack_expansion later (PR101764). */
4250 }
4252 /* Checks T for any "bare" parameter packs, which have not yet been
4253 expanded, and issues an error if any are found. This operation can
4254 only be done on full expressions or types (e.g., an expression
4255 statement, "if" condition, etc.), because we could have expressions like:
4257 foo(f(g(h(args)))...)
4259 where "args" is a parameter pack. check_for_bare_parameter_packs
4260 should not be called for the subexpressions args, h(args),
4261 g(h(args)), or f(g(h(args))), because we would produce erroneous
4262 error messages.
4264 Returns TRUE and emits an error if there were bare parameter packs,
4265 returns FALSE otherwise. */
4266 bool
4268 {
4290 /* It's OK for a lambda to have an unexpanded parameter pack from the
4291 containing context, but do complain about unexpanded capture packs. */
4297 {
4298 /* We're in a lambda, but it isn't the innermost class.
4299 This should work, but currently doesn't. */
4302 }
4307 {
4313 }
4316 {
4319 {
4330 else
4335 else
4339 }
4342 }
4345 }
4347 /* Expand any parameter packs that occur in the template arguments in
4348 ARGS. */
4349 tree
4351 {
4360 /* First, determine if we need to expand anything, and the number of
4361 slots we'll need. */
4363 {
4368 {
4372 else
4374 }
4375 else
4376 {
4378 num_result_args++;
4379 }
4380 }
4382 /* If no expansion is necessary, we're done. */
4386 /* Expand arguments. */
4389 non_default_args_count =
4392 {
4395 {
4402 }
4403 else
4404 {
4407 }
4408 }
4412 }
4414 /* Checks if DECL shadows a template parameter.
4416 [temp.local]: A template-parameter shall not be redeclared within its
4417 scope (including nested scopes).
4419 Emits an error and returns TRUE if the DECL shadows a parameter,
4420 returns FALSE otherwise. */
4422 bool
4424 {
4425 tree olddecl;
4427 /* If we're not in a template, we can't possibly shadow a template
4428 parameter. */
4432 /* Figure out what we're shadowing. */
4436 /* If there's no previous binding for this name, we're not shadowing
4437 anything, let alone a template parameter. */
4441 /* If we're not shadowing a template parameter, we're done. Note
4442 that OLDDECL might be an OVERLOAD (or perhaps even an
4443 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4444 node. */
4448 /* We check for decl != olddecl to avoid bogus errors for using a
4449 name inside a class. We check TPFI to avoid duplicate errors for
4450 inline member templates. */
4456 /* Don't complain about the injected class name, as we've already
4457 complained about the class itself. */
4464 else
4469 }
4471 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4472 ORIG_LEVEL, DECL, and TYPE. */
4474 static tree
4478 tree decl,
4479 tree type)
4480 {
4491 }
4494 {
4496 {
4506 }
4509 {
4514 }
4515 };
4519 /* Find the canonical type parameter for the given template type
4520 parameter. Returns the canonical type parameter, which may be TYPE
4521 if no such parameter existed. */
4523 tree
4525 {
4533 }
4535 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4536 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4537 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4538 new one is created. */
4540 static tree
4542 tsubst_flags_t complain)
4543 {
4548 {
4553 type);
4568 /* Template template parameters need this. */
4571 {
4583 }
4585 /* Attach the TPI to the decl. */
4588 else
4590 }
4593 }
4595 /* Process information from new template parameter PARM and append it
4596 to the LIST being built. This new parameter is a non-type
4597 parameter iff IS_NON_TYPE is true. This new parameter is a
4598 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4599 is in PARM_LOC. */
4601 tree
4604 {
4610 {
4620 }
4627 {
4633 {
4634 /* [temp.param]
4636 The top-level cv-qualifiers on the template-parameter are
4637 ignored when determining its type. */
4642 && !is_parameter_pack
4643 /* If we're in a nested template parameter list, the template
4644 template parameter could be a parameter pack. */
4646 {
4647 /* This template parameter is not a parameter pack, but it
4648 should be. Complain about "bare" parameter packs. */
4651 /* Recover by calling this a parameter pack. */
4653 }
4654 }
4656 /* A template parameter is not modifiable. */
4665 current_template_depth,
4670 }
4671 else
4672 {
4673 tree t;
4677 {
4679 /* This is for distinguishing between real templates and template
4680 template parameters */
4683 /* any_template_parm_r expects to be able to get the targs of a
4684 DECL_TEMPLATE_RESULT. */
4693 }
4694 else
4695 {
4697 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4700 }
4707 current_template_depth,
4711 }
4719 /* Build requirements for the type/template parameter.
4720 This must be done after SET_DECL_TEMPLATE_PARM_P or
4721 process_template_parm could fail. */
4728 /* Build the parameter node linking the parameter declaration,
4729 its default argument (if any), and its constraints (if any). */
4735 else
4739 }
4741 /* The end of a template parameter list has been reached. Process the
4742 tree list into a parameter vector, converting each parameter into a more
4743 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4744 as PARM_DECLs. */
4746 tree
4748 {
4751 /* Pop the dummy parameter level and add the real one. We do not
4752 morph the dummy parameter in place, as it might have been
4753 captured by a (nested) template-template-parm. */
4756 current_template_parms
4761 {
4767 }
4772 }
4774 // Explicitly indicate the end of the template parameter list. We assume
4775 // that the current template parameters have been constructed and/or
4776 // managed explicitly, as when creating new template template parameters
4777 // from a shorthand constraint.
4778 void
4780 {
4782 }
4784 /* end_template_decl is called after a template declaration is seen. */
4786 void
4788 {
4794 /* This matches the pushlevel in begin_template_parm_list. */
4799 }
4801 /* Takes a TEMPLATE_PARM_P or DECL_TEMPLATE_PARM_P node or a TREE_LIST
4802 thereof, and converts it into an argument suitable to be passed to
4803 the type substitution functions. Note that if the TREE_LIST contains
4804 an error_mark node, the returned argument is error_mark_node. */
4806 tree
4808 {
4819 {
4823 else
4825 }
4831 {
4833 {
4834 /* Turn this argument into a TYPE_ARGUMENT_PACK
4835 with a single element, which expands T. */
4844 }
4845 }
4846 else
4847 {
4849 {
4850 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4851 with a single element, which expands T. */
4861 }
4862 else
4864 }
4866 }
4868 /* If T looks like a generic template argument produced by template_parm_to_arg,
4869 return the corresponding template parameter, otherwise return NULL_TREE. */
4871 static tree
4873 {
4878 {
4883 }
4890 else
4892 }
4894 /* Given a single level of template parameters (a TREE_VEC), return it
4895 as a set of template arguments. */
4897 tree
4899 {
4909 }
4911 /* Given a set of template parameters, return them as a set of template
4912 arguments. The template parameters are represented as a TREE_VEC, in
4913 the form documented in cp-tree.h for template arguments. */
4915 tree
4917 {
4918 tree header;
4923 /* If there is only one level of template parameters, we do not
4924 create a TREE_VEC of TREE_VECs. Instead, we return a single
4925 TREE_VEC containing the arguments. */
4930 {
4935 else
4937 }
4940 }
4942 /* Within the declaration of a template, return the currently active
4943 template parameters as an argument TREE_VEC. */
4945 static tree
4947 {
4949 }
4951 /* Return the fully generic arguments for of TMPL, i.e. what
4952 current_template_args would be while parsing it. */
4954 tree
4956 {
4961 /* DECL_TEMPLATE_RESULT doesn't have the arguments we want. For a template
4962 template parameter, it has no TEMPLATE_INFO; for a partial
4963 specialization, it has the arguments for the primary template, and we
4969 }
4971 /* Return the template arguments corresponding to the template parameters of
4972 DECL's enclosing scope. When DECL is a member of a partial specialization,
4973 this returns the arguments for the partial specialization as opposed to those
4974 for the primary template, which is the main difference between this function
4975 and simply using e.g. the TYPE_TI_ARGS of DECL's DECL_CONTEXT. */
4977 tree
4979 {
4991 }
4993 /* Update the declared TYPE by doing any lookups which were thought to be
4994 dependent, but are not now that we know the SCOPE of the declarator. */
4996 tree
4998 {
5009 /* Don't bother building up the args in this case. */
5011 {
5012 /* tsubst in the args corresponding to the template parameters,
5013 including auto if present. Most things will be unchanged, but
5014 make_typename_type and tsubst_qualified_id will resolve
5015 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
5018 tree pushed;
5020 {
5024 }
5029 }
5035 {
5038 else
5040 }
5042 }
5044 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
5045 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
5046 the new template is a member template. */
5048 static tree
5050 {
5062 /* Propagate module information from the decl. */
5066 }
5068 struct template_parm_data
5069 {
5070 /* The level of the template parameters we are currently
5071 processing. */
5074 /* The index of the specialization argument we are currently
5075 processing. */
5078 /* An array whose size is the number of template parameters. The
5079 elements are nonzero if the parameter has been used in any one
5080 of the arguments processed so far. */
5083 /* An array whose size is the number of template arguments. The
5084 elements are nonzero if the argument makes use of template
5085 parameters of this level. */
5087 };
5089 /* Subroutine of push_template_decl used to see if each template
5090 parameter in a partial specialization is used in the explicit
5091 argument list. If T is of the LEVEL given in DATA (which is
5092 treated as a template_parm_data*), then DATA->PARMS is marked
5093 appropriately. */
5095 static int
5097 {
5105 {
5108 }
5110 /* In C++17 the type of a non-type argument is a deduced context. */
5115 data,
5116 NULL,
5119 /* Return zero so that for_each_template_parm will continue the
5120 traversal of the tree; we want to mark *every* template parm. */
5122 }
5124 /* Process the partial specialization DECL. */
5126 static tree
5128 {
5135 tree inner_parms;
5136 tree inst;
5146 /* A concept cannot be specialized. */
5148 {
5151 }
5156 /* We check that each of the template parameters given in the
5157 partial specialization is used in the argument list to the
5158 specialization. For example:
5160 template <class T> struct S;
5161 template <class T> struct S<T*>;
5163 The second declaration is OK because `T*' uses the template
5164 parameter T, whereas
5166 template <class T> struct S<int>;
5168 is no good. Even trickier is:
5170 template <class T>
5171 struct S1
5172 {
5173 template <class U>
5174 struct S2;
5175 template <class U>
5176 struct S2<T>;
5177 };
5179 The S2<T> declaration is actually invalid; it is a
5180 full-specialization. Of course,
5182 template <class U>
5183 struct S2<T (*)(U)>;
5185 or some such would have been OK. */
5193 {
5198 NULL,
5200 }
5203 {
5204 /* One of the template parms was not used in a deduced context in the
5205 specialization. */
5207 {
5211 }
5215 }
5220 /* [temp.class.spec]
5222 The argument list of the specialization shall not be identical to
5223 the implicit argument list of the primary template. */
5224 tree main_args
5227 && (!flag_concepts
5229 {
5232 "any template arguments; to define the primary template, "
5234 else
5236 "template arguments and is not more constrained than "
5237 "the primary template; to define the primary template, "
5240 }
5242 /* A partial specialization that replaces multiple parameters of the
5243 primary template with a pack expansion is less specialized for those
5244 parameters. */
5246 {
5248 "primary template because it replaces multiple parameters "
5251 /* Avoid crash in process_partial_specialization. */
5253 }
5256 {
5259 /* Avoid crash below. */
5261 }
5263 /* If we aren't in a dependent class, we can actually try deduction. */
5265 /* FIXME we should be able to handle a partial specialization of a
5266 partial instantiation, but currently we can't (c++/41727). */
5269 {
5270 auto_diagnostic_group d;
5273 decl))
5275 maintmpl);
5276 }
5278 /* [temp.spec.partial]
5280 The type of a template parameter corresponding to a specialized
5281 non-type argument shall not be dependent on a parameter of the
5282 specialization.
5284 Also, we verify that pack expansions only occur at the
5285 end of the argument list. */
5288 {
5295 {
5296 /* Extract the arguments from the argument pack. We'll be
5297 iterating over these in the following loop. */
5300 }
5303 {
5305 /* Get the Jth argument in the parameter pack. */
5309 {
5310 /* Pack expansions must come at the end of the
5311 argument list. */
5314 {
5318 else
5321 }
5322 }
5325 /* We only care about the pattern. */
5331 /* This next two lines are the `argument expression is not just a
5332 simple identifier' condition and also the `specialized
5333 non-type argument' bit. */
5338 {
5339 /* Look at the corresponding template parameter,
5340 marking which template parameters its type depends
5341 upon. */
5345 {
5346 /* We haven't yet initialized TPD2. Do so now. */
5348 /* The number of parameters here is the number in the
5349 main template, which, as checked in the assertion
5350 above, is NARGS. */
5354 }
5356 /* Mark the template parameters. But this time, we're
5357 looking for the template parameters of the main
5358 template, not in the specialization. */
5365 NULL,
5369 {
5370 /* The type depended on some template parameters.
5371 If they are fully specialized in the
5372 specialization, that's OK. */
5381 "type %qT of template argument %qE depends "
5383 "type %qT of template argument %qE depends "
5385 type,
5386 arg);
5387 }
5388 }
5389 }
5390 }
5392 /* We should only get here once. */
5396 // Build the template decl.
5403 /* Give template template parms a DECL_CONTEXT of the template
5404 for which they are a parameter. */
5406 {
5410 }
5413 /* We didn't register this in check_explicit_specialization so we could
5414 wait until the constraints were set. */
5416 else
5423 /* Link the DECL_TEMPLATE_RESULT back to the partial TEMPLATE_DECL. */
5429 {
5435 {
5444 "declaration of %qD ambiguates earlier template "
5448 "partial specialization of %qD after instantiation "
5450 }
5451 }
5454 }
5456 /* PARM is a template parameter of some form; return the corresponding
5457 TEMPLATE_PARM_INDEX. */
5459 static tree
5461 {
5474 }
5476 /* Subroutine of fixed_parameter_pack_p below. Look for any template
5477 parameter packs used by the template parameter PARM. */
5479 static void
5481 {
5482 /* A type parm can't refer to another parm. */
5486 {
5490 }
5496 {
5500 else
5502 }
5503 }
5505 /* PARM is a template parameter pack. Return any parameter packs used in
5506 its type or the type of any of its template parameters. If there are
5507 any such packs, it will be instantiated into a fixed template parameter
5508 list by partial instantiation rather than be fully deduced. */
5510 tree
5512 {
5513 /* This can only be true in a member template. */
5516 /* This can only be true for a parameter pack. */
5519 /* A type parm can't refer to another parm. */
5533 }
5535 /* Check that a template declaration's use of default arguments and
5536 parameter packs is not invalid. Here, PARMS are the template
5537 parameters. IS_PRIMARY is true if DECL is the thing declared by
5538 a primary template. IS_PARTIAL is true if DECL is a partial
5539 specialization.
5541 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
5542 function template declaration or a friend class template
5543 declaration. In the function case, 1 indicates a declaration, 2
5544 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
5545 emitted for extraneous default arguments.
5547 Returns TRUE if there were no errors found, FALSE otherwise. */
5549 bool
5552 {
5555 tree parm_level;
5558 /* [temp.param]
5560 A default template-argument shall not be specified in a
5561 function template declaration or a function template definition, nor
5562 in the template-parameter-list of the definition of a member of a
5563 class template. */
5567 /* You can't have a function template declaration in a local
5568 scope, nor you can you define a member of a class template in a
5569 local scope. */
5577 /* A lambda doesn't have an explicit declaration; don't complain
5578 about the parms of the enclosing class. */
5585 /* If this is either a friend defined in the scope of the class
5586 or a member function. */
5592 /* And, if it was a member function, it really was defined in
5593 the scope of the class. */
5596 /* We already checked these parameters when the template was
5597 declared, so there's no need to do it again now. This function
5598 was defined in class scope, but we're processing its body now
5599 that the class is complete. */
5602 /* Core issue 226 (C++0x only): the following only applies to class
5603 templates. */
5606 {
5607 /* [temp.param]
5609 If a template-parameter has a default template-argument, all
5610 subsequent template-parameters shall have a default
5611 template-argument supplied. */
5613 {
5620 {
5630 {
5632 /* For better subsequent error-recovery, we indicate that
5633 there should have been a default argument. */
5636 }
5638 && !is_friend_decl
5639 /* Don't complain about an enclosing partial
5640 specialization. */
5645 /* A fixed parameter pack will be partially
5646 instantiated into a fixed length list. */
5648 {
5649 /* A primary class template, primary variable template
5650 (DR 2032), or alias template can only have one
5651 parameter pack, at the end of the template
5652 parameter list. */
5660 }
5661 }
5662 }
5663 }
5666 || is_partial
5667 || !is_primary
5669 /* For an ordinary class template, default template arguments are
5670 allowed at the innermost level, e.g.:
5671 template <class T = int>
5672 struct S {};
5673 but, in a partial specialization, they're not allowed even
5674 there, as we have in [temp.class.spec]:
5676 The template parameter list of a specialization shall not
5677 contain default template argument values.
5679 So, for a partial specialization, or for a function template
5680 (in C++98/C++03), we look at all of them. */
5681 ;
5682 else
5683 /* But, for a primary class template that is not a partial
5684 specialization we look at all template parameters except the
5685 innermost ones. */
5688 /* Figure out what error message to issue. */
5703 else
5704 /* Per [temp.param]/9, "A default template-argument shall not be
5705 specified in the template-parameter-lists of the definition of
5706 a member of a class template that appears outside of the member's
5707 class.", thus if we aren't handling a member of a class template
5708 there is no need to examine the parameters. */
5712 /* If we're inside a class definition, there's no need to
5713 examine the parameters to the class itself. On the one
5714 hand, they will be checked when the class is defined, and,
5715 on the other, default arguments are valid in things like:
5716 template <class T = double>
5717 struct S { template <class U> void f(U); };
5718 Here the default argument for `S' has no bearing on the
5719 declaration of `f'. */
5721 else
5722 /* Check everything. */
5728 {
5735 {
5740 {
5742 {
5749 }
5751 /* Clear out the default argument so that we are not
5752 confused later. */
5754 }
5755 }
5757 /* At this point, if we're still interested in issuing messages,
5758 they must apply to classes surrounding the object declared. */
5762 }
5765 }
5767 /* Worker for push_template_decl_real, called via
5768 for_each_template_parm. DATA is really an int, indicating the
5769 level of the parameters we are interested in. If T is a template
5770 parameter of that level, return nonzero. */
5772 static int
5774 {
5780 else
5783 }
5785 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5786 DATA is really an int, indicating the innermost outer level of parameters.
5787 If T is a template parameter of that level or further out, return
5788 nonzero. */
5790 static int
5792 {
5798 else
5801 }
5803 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5804 parameters given by current_template_args, or reuses a
5805 previously existing one, if appropriate. Returns the DECL, or an
5806 equivalent one, if it is replaced via a call to duplicate_decls.
5808 If IS_FRIEND is true, DECL is a friend declaration. */
5810 tree
5812 {
5816 /* See if this is a partial specialization. */
5825 /* No surprising friend functions. */
5830 tree ctx;
5832 /* For a friend, we want the context of the friend, not
5833 the type of which it is a friend. */
5837 /* In the case of a virtual function, we want the class in which
5838 it is defined. */
5840 else
5841 /* Otherwise, if we're currently defining some class, the DECL
5842 is assumed to be a member of the class. */
5851 /* See if this is a primary template. */
5855 /* A friend template that specifies a class context, i.e.
5856 template <typename T> friend void A<T>::f();
5857 is not primary. */
5858 ;
5860 /* Lambdas are not primary. */
5861 ;
5862 else
5865 /* True if the template is a member template, in the sense of
5866 [temp.mem]. */
5870 {
5878 {
5881 }
5883 {
5885 {
5888 }
5890 {
5891 /* [temp.mem]
5893 A destructor shall not be a member template. */
5897 }
5904 {
5905 /* [basic.stc.dynamic.allocation]
5907 An allocation function can be a function
5908 template. ... Template allocation functions shall
5909 have two or more parameters. */
5912 }
5913 }
5919 /* alias-declaration */
5925 else
5926 {
5929 }
5930 }
5937 /* Check to see that the rules regarding the use of default
5938 arguments are not being violated. We check args for a friend
5939 functions when we know whether it's a definition, introducing
5940 declaration or re-declaration. */
5945 /* Ensure that there are no parameter packs in the type of this
5946 declaration that have not been expanded. */
5948 {
5949 /* Check each of the arguments individually to see if there are
5950 any bare parameter packs. */
5956 {
5959 {
5960 /* This is a PARM_DECL that contains unexpanded parameter
5961 packs. We have already complained about this in the
5962 check_for_bare_parameter_packs call, so just replace
5963 these types with ERROR_MARK_NODE. */
5966 }
5970 }
5972 /* Check for bare parameter packs in the return type and the
5973 exception specifiers. */
5975 /* Errors were already issued, set return type to int
5976 as the frontend doesn't expect error_mark_node as
5977 the return type. */
5981 }
5982 else
5983 {
5987 {
5990 }
5995 }
6004 {
6005 /* Does not get a template head. */
6008 }
6015 {
6020 /* If DECL is a TYPE_DECL for a class-template, then there won't
6021 be DECL_LANG_SPECIFIC. The information equivalent to
6022 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
6026 {
6027 /* Since a template declaration already existed for this
6028 class-type, we must be redeclaring it here. Make sure
6029 that the redeclaration is valid. */
6031 current_template_parms,
6033 /* We don't need to create a new TEMPLATE_DECL; just use the
6034 one we already had. */
6036 }
6037 else
6038 {
6040 member_template_p);
6045 {
6046 /* A specialization of a member template of a template
6047 class. */
6051 }
6052 }
6053 }
6054 else
6055 {
6061 {
6064 }
6072 {
6073 /* The declaration is a specialization of a member
6074 template, declared outside the class. Therefore, the
6075 innermost template arguments will be NULL, so we
6076 replace them with the arguments determined by the
6077 earlier call to check_explicit_specialization. */
6080 tree new_tmpl
6082 member_template_p);
6090 args,
6093 }
6095 /* Make sure the template headers we got make sense. */
6100 {
6105 }
6106 else
6108 {
6113 {
6117 else
6121 /* Avoid crash in import_export_decl. */
6124 }
6129 /* Can happen in erroneous input. */
6131 else
6133 }
6135 /* Check that the parms are used in the appropriate qualifying scopes
6136 in the declarator. */
6140 {
6146 /* Avoid crash in import_export_decl. */
6149 }
6151 /* Check that the constraints for each enclosing template scope are
6152 consistent with the original declarations. */
6154 {
6158 {
6161 }
6163 {
6165 {
6169 }
6172 }
6173 }
6174 }
6179 {
6180 /* Push template declarations for global functions and types.
6181 Note that we do not try to push a global template friend
6182 declared in a template class; such a thing may well depend on
6183 the template parameters of the class and we'll push it when
6184 instantiating the befriending class. */
6187 {
6192 /* pushdecl may have found an existing template. */
6194 {
6197 }
6198 }
6200 {
6201 /* Record this decl as belonging to the current class. It's
6202 not chained onto anything else. */
6206 }
6207 }
6209 /* The type may have been completed, or (erroneously) changed. */
6213 {
6215 {
6220 /* Give template template parms a DECL_CONTEXT of the template
6221 for which they are a parameter. */
6224 {
6228 }
6232 {
6235 {
6236 /* ??? Why don't we do this here for all templates? */
6239 }
6240 }
6241 }
6243 /* The DECL_TI_ARGS of DECL contains full set of arguments
6244 referring wback to its most general template. If TMPL is a
6245 specialization, ARGS may only have the innermost set of
6246 arguments. Add the missing argument levels if necessary. */
6254 else
6255 {
6258 }
6259 }
6262 && !is_friend
6265 /* Set DECL_COMDAT on template instantiations; if we force
6266 them to be emitted by explicit instantiation,
6267 mark_needed will tell cgraph to do the right thing. */
6273 }
6275 /* FN is an inheriting constructor that inherits from the constructor
6276 template INHERITED; turn FN into a constructor template with a matching
6277 template header. */
6279 tree
6281 {
6282 tree inner_parms
6285 tree parms
6294 }
6296 /* Called when a class template TYPE is redeclared with the indicated
6297 template PARMS, e.g.:
6299 template <class T> struct S;
6300 template <class T> struct S {}; */
6302 bool
6304 {
6305 tree tmpl;
6306 tree tmpl_parms;
6310 {
6313 }
6317 /* The type is nested in some template class. Nothing to worry
6318 about here; there are no new template parameters for the nested
6319 type. */
6323 {
6325 tmpl);
6327 }
6333 {
6343 }
6346 {
6347 tree tmpl_parm;
6348 tree parm;
6360 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
6361 TEMPLATE_DECL. */
6371 {
6372 auto_diagnostic_group d;
6376 else
6379 }
6381 /* The parameters can be declared to introduce different
6382 constraints. */
6386 {
6387 auto_diagnostic_group d;
6393 }
6395 /* Give each template template parm in this redeclaration a
6396 DECL_CONTEXT of the template for which they are a parameter. */
6398 {
6402 }
6403 }
6412 /* Two classes with different constraints declare different entities. */
6414 {
6415 auto_diagnostic_group d;
6421 }
6424 }
6426 /* The actual substitution part of instantiate_non_dependent_expr,
6427 to be used when the caller has already checked
6428 !instantiation_dependent_uneval_expression_p (expr)
6429 and cleared processing_template_decl. */
6431 tree
6433 {
6435 }
6437 /* Instantiate the non-dependent expression EXPR. */
6439 tree
6442 {
6447 {
6448 /* The caller should have checked this already. */
6450 processing_template_decl_sentinel s;
6452 }
6454 }
6456 /* Like instantiate_non_dependent_expr, but return NULL_TREE if the
6457 expression is dependent or non-constant. */
6459 tree
6461 {
6465 {
6468 else
6469 {
6470 processing_template_decl_sentinel s;
6472 }
6473 }
6475 }
6477 /* True iff T is a specialization of a variable template. */
6479 bool
6481 {
6486 }
6488 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
6489 template declaration, or a TYPE_DECL for an alias declaration. */
6491 bool
6493 {
6501 }
6503 /* If T is a specialization of an alias template, return it; otherwise return
6504 NULL_TREE. If TRANSPARENT_TYPEDEFS is true, look through other aliases. */
6506 tree
6509 {
6513 /* It's an alias template specialization if it's an alias and its
6514 TYPE_NAME is a specialization of a primary template. */
6516 {
6523 transparent_typedefs);
6524 }
6527 }
6529 /* A cache of the result of complex_alias_template_p. */
6533 /* Data structure for complex_alias_template_*. */
6535 struct uses_all_template_parms_data
6536 {
6539 };
6541 /* walk_tree callback for complex_alias_template_p. */
6543 static tree
6545 {
6550 {
6555 {
6559 }
6562 }
6567 /* An alias template with a pack expansion that expands a pack from the
6568 enclosing class needs to be considered complex, to avoid confusion with
6569 the same pack being used as an argument to the alias's own template
6570 parameter (91966). */
6573 {
6582 /* Consider the expanded packs to be used outside the expansion... */
6584 }
6586 /* ...but don't walk into the pattern. Consider PR104008:
6588 template <typename T, typename... Ts>
6589 using IsOneOf = disjunction<is_same<T, Ts>...>;
6591 where IsOneOf seemingly uses all of its template parameters in its
6592 expansion (and does not expand a pack from the enclosing class), so the
6593 alias was not marked as complex. However, if it is used like
6594 "IsOneOf<T>", the empty pack for Ts means that T no longer appears in the
6595 expansion. So only Ts is considered used by the pack expansion. */
6599 }
6601 /* An alias template is complex from a SFINAE perspective if a template-id
6602 using that alias can be ill-formed when the expansion is not, as with
6603 the void_t template.
6605 If this predicate returns true in the ordinary case, the out parameter
6606 SEEN_OUT is set to a TREE_VEC containing boolean_true_node at element I if
6607 the I'th template parameter of the alias template is used in the alias. */
6609 static bool
6611 {
6616 /* A renaming alias isn't complex. */
6620 /* Any other constrained alias is complex. */
6628 {
6638 }
6651 {
6654 }
6658 {
6663 }
6667 }
6669 /* If T is a specialization of a complex alias template with a dependent
6670 argument for an unused template parameter, return it; otherwise return
6671 NULL_TREE. If T is a typedef to such a specialization, return the
6672 specialization. */
6674 tree
6676 {
6685 {
6688 {
6691 {
6694 }
6695 else
6696 {
6702 }
6705 }
6706 }
6709 {
6712 }
6715 }
6717 /* Return the number of innermost template parameters in TMPL. */
6719 static int
6721 {
6724 }
6726 /* Return either TMPL or another template that it is equivalent to under DR
6727 1286: An alias that just changes the name of a template is equivalent to
6728 the other template. */
6730 static tree
6732 {
6735 {
6736 /* Determine if the alias is equivalent to an underlying template. */
6738 /* The underlying type may have been ill-formed. Don't proceed. */
6751 /* Does the alias add cv-quals? */
6759 /* Are any default template arguments equivalent? */
6764 {
6769 }
6771 /* If TMPL adds or changes any constraints, it isn't equivalent. I think
6772 it's appropriate to treat a less-constrained alias as equivalent. */
6776 /* Alias is equivalent. Strip it and repeat. */
6778 }
6779 top_break:;
6782 }
6784 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6785 must be a reference-to-function or a pointer-to-function type, as specified
6786 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6787 and check that the resulting function has external linkage. */
6789 static tree
6791 tsubst_flags_t complain)
6792 {
6795 linkage_kind linkage;
6813 /* [temp.arg.nontype]/1
6815 A template-argument for a non-type, non-template template-parameter
6816 shall be one of:
6817 [...]
6818 -- the address of an object or function with external [C++11: or
6819 internal] linkage. */
6823 {
6825 {
6832 else
6835 }
6837 }
6842 {
6844 {
6850 else
6854 }
6856 }
6858 accept:
6860 {
6863 else
6865 }
6870 }
6872 /* Subroutine of convert_nontype_argument.
6873 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6874 Emit an error otherwise. */
6876 static bool
6878 tsubst_flags_t complain)
6879 {
6895 {
6901 else
6903 }
6905 }
6907 /* Returns TRUE iff the address of OP is value-dependent.
6909 14.6.2.4 [temp.dep.temp]:
6910 A non-integral non-type template-argument is dependent if its type is
6911 dependent or it has either of the following forms
6912 qualified-id
6913 & qualified-id
6914 and contains a nested-name-specifier which specifies a class-name that
6915 names a dependent type.
6917 We generalize this to just say that the address of a member of a
6918 dependent class is value-dependent; the above doesn't cover the
6919 address of a static data member named with an unqualified-id. */
6921 static bool
6923 {
6926 /* We could use get_inner_reference here, but there's no need;
6927 this is only relevant for template non-type arguments, which
6928 can only be expressed as &id-expression. */
6930 {
6941 }
6944 }
6946 /* The next set of functions are used for providing helpful explanatory
6947 diagnostics for failed overload resolution. Their messages should be
6948 indented by two spaces for consistency with the messages in
6949 call.cc */
6951 static int
6953 {
6955 }
6957 /* Other failure functions should call this one, to provide a single function
6958 for setting a breakpoint on. */
6960 static int
6962 {
6964 }
6966 static int
6968 {
6973 }
6975 static int
6977 {
6983 }
6985 static int
6987 {
6991 }
6993 static int
6995 {
6998 " template parameter %qD is not a parameter pack, but "
7002 }
7004 static int
7006 {
7009 " template argument %qE does not match "
7013 }
7015 static int
7017 {
7021 }
7023 static int
7025 {
7031 }
7033 static int
7035 {
7037 {
7042 else
7044 " deduced conflicting values for non-type parameter "
7046 }
7048 }
7050 static int
7052 {
7055 " variable-sized array type %qT is not "
7057 arg);
7059 }
7061 static int
7063 {
7067 arg);
7069 }
7071 static int
7073 {
7075 {
7081 else
7086 }
7088 }
7090 static int
7092 {
7094 }
7096 static int
7099 {
7101 }
7103 static int
7106 {
7112 }
7114 static int
7117 {
7120 {
7128 }
7130 }
7132 static int
7134 {
7137 " template parameters of a template template argument are "
7140 }
7142 static int
7144 {
7150 }
7152 static int
7154 {
7159 }
7161 /* Subroutine of convert_nontype_argument, to check whether EXPR, as an
7162 argument for TYPE, points to an unsuitable object.
7164 Also adjust the type of the index in C++20 array subobject references. */
7166 static bool
7168 {
7170 {
7171 CASE_CONVERT:
7173 complain);
7177 complain);
7180 {
7184 }
7188 {
7194 {
7198 /* Canonicalize array offsets to ptrdiff_t; how they were
7199 written doesn't matter for subobject identity. */
7202 }
7205 {
7208 "%qE is not a valid template argument of type %qT "
7212 }
7214 {
7217 "%qE is not a valid template argument of type %qT "
7221 }
7224 {
7227 "%qE is not a valid template argument of type %qT "
7230 }
7231 /* C++17: For a non-type template-parameter of reference or pointer
7232 type, the value of the constant expression shall not refer to (or
7233 for a pointer type, shall not be the address of):
7234 * a subobject (4.5),
7235 * a temporary object (15.2),
7236 * a string literal (5.13.5),
7237 * the result of a typeid expression (8.2.8), or
7238 * a predefined __func__ variable (11.4.1). */
7241 {
7245 decl);
7247 }
7249 && !(same_type_ignoring_top_level_qualifiers_p
7252 {
7257 }
7259 {
7263 decl);
7265 }
7266 }
7274 else
7275 {
7277 {
7280 "because %qD is a variable, not the address of "
7283 }
7284 else
7285 {
7291 }
7292 }
7293 }
7296 }
7298 /* Return a VAR_DECL for the C++20 template parameter object corresponding to
7299 template argument EXPR. */
7301 static tree
7303 {
7308 {
7313 }
7317 /* This is no longer a compound literal. */
7321 }
7323 /* The template arguments corresponding to template parameter objects of types
7324 that contain pointers to members. */
7328 /* Find or build an nttp object for (already-validated) EXPR with name
7329 NAME. */
7331 tree
7333 {
7350 {
7351 /* If EXPR contains any PTRMEM_CST, they will get clobbered by
7352 lower_var_init before we're done mangling. So store the original
7353 value elsewhere. */
7356 }
7361 }
7363 /* Return the actual template argument corresponding to template parameter
7364 object VAR. */
7366 tree
7368 {
7372 }
7374 /* Attempt to convert the non-type template parameter EXPR to the
7375 indicated TYPE. If the conversion is successful, return the
7376 converted value. If the conversion is unsuccessful, return
7377 NULL_TREE if we issued an error message, or error_mark_node if we
7378 did not. We issue error messages for out-and-out bad template
7379 parameters, but not simply because the conversion failed, since we
7380 might be just trying to do argument deduction. Both TYPE and EXPR
7381 must be non-dependent.
7383 The conversion follows the special rules described in
7384 [temp.arg.nontype], and it is much more strict than an implicit
7385 conversion.
7387 This function is called twice for each template argument (see
7388 lookup_template_class for a more accurate description of this
7389 problem). This means that we need to handle expressions which
7390 are not valid in a C++ source, but can be created from the
7391 first call (for instance, casts to perform conversions). These
7392 hacks can go away after we fix the double coercion problem. */
7394 static tree
7396 {
7397 tree expr_type;
7400 /* Detect immediately string literals as invalid non-type argument.
7401 This special-case is not needed for correctness (we would easily
7402 catch this later), but only to provide better diagnostic for this
7403 common user mistake. As suggested by DR 100, we do not mention
7404 linkage issues in the diagnostic as this is not the point. */
7406 {
7412 }
7414 /* Add the ADDR_EXPR now for the benefit of
7415 value_dependent_expression_p. */
7418 {
7422 }
7424 /* If we are in a template, EXPR may be non-dependent, but still
7425 have a syntactic, rather than semantic, form. For example, EXPR
7426 might be a SCOPE_REF, rather than the VAR_DECL to which the
7427 SCOPE_REF refers. Preserving the qualifying scope is necessary
7428 so that access checking can be performed when the template is
7429 instantiated -- but here we need the resolved form so that we can
7430 convert the argument. */
7442 /* If the argument is non-dependent, perform any conversions in
7443 non-dependent context as well. */
7451 else
7454 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
7455 to a non-type argument of "nullptr". */
7459 /* In C++11, integral or enumeration non-type template arguments can be
7460 arbitrary constant expressions. Pointer and pointer to
7461 member arguments can be general constant expressions that evaluate
7462 to a null value, but otherwise still need to be of a specific form. */
7464 {
7466 /* A PTRMEM_CST is already constant, and a valid template
7467 argument for a parameter of pointer to member type, we just want
7468 to leave it in that form rather than lower it to a
7472 {
7473 /* C++17: A template-argument for a non-type template-parameter shall
7474 be a converted constant expression (8.20) of the type of the
7475 template-parameter. */
7478 /* Make sure we return NULL_TREE only if we have really issued
7479 an error, as described above. */
7482 {
7485 }
7488 /* EXPR may have become value-dependent. */
7490 }
7492 {
7497 }
7498 }
7502 else
7505 /* HACK: Due to double coercion, we can get a
7506 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
7507 which is the tree that we built on the first call (see
7508 below when coercing to reference to object or to reference to
7509 function). We just strip everything and get to the arg.
7510 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
7511 for examples. */
7513 {
7514 /* Check this before we strip *& to avoid redundancy. */
7523 {
7524 /* ??? Maybe we could use convert_from_reference here, but we
7525 would need to relax its constraints because the NOP_EXPR
7526 could actually change the type to something more cv-qualified,
7527 and this is not folded by convert_from_reference. */
7532 && (same_type_ignoring_top_level_qualifiers_p
7535 {
7538 }
7539 }
7540 }
7542 /* [temp.arg.nontype]/5, bullet 1
7544 For a non-type template-parameter of integral or enumeration type,
7545 integral promotions (_conv.prom_) and integral conversions
7546 (_conv.integral_) are applied. */
7549 {
7551 {
7556 }
7561 /* Notice that there are constant expressions like '4 % 0' which
7562 do not fold into integer constants. */
7564 {
7566 {
7570 else
7576 /* else cxx_constant_value complained but gave us
7577 a real constant, so go ahead. */
7579 {
7580 /* Some assemble time constant expressions like
7581 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
7582 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
7583 as we can emit them into .rodata initializers of
7584 variables, yet they can't fold into an INTEGER_CST at
7585 compile time. Refuse them here. */
7590 }
7591 }
7592 else
7594 }
7596 /* Avoid typedef problems. */
7599 }
7600 /* [temp.arg.nontype]/5, bullet 2
7602 For a non-type template-parameter of type pointer to object,
7603 qualification conversions (_conv.qual_) and the array-to-pointer
7604 conversion (_conv.array_) are applied. */
7606 {
7609 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
7610 decay_conversion or an explicit cast. If it's a problematic cast,
7611 we'll complain about it below. */
7613 {
7618 {
7621 }
7622 }
7624 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
7626 A template-argument for a non-type, non-template template-parameter
7627 shall be one of: [...]
7629 -- the name of a non-type template-parameter;
7630 -- the address of an object or function with external linkage, [...]
7631 expressed as "& id-expression" where the & is optional if the name
7632 refers to a function or array, or if the corresponding
7633 template-parameter is a reference.
7635 Here, we do not care about functions, as they are invalid anyway
7636 for a parameter of type pointer-to-object. */
7639 /* Non-type template parameters are OK. */
7640 ;
7645 /* Other values, like integer constants, might be valid
7646 non-type arguments of some other type. */
7656 }
7657 /* [temp.arg.nontype]/5, bullet 3
7659 For a non-type template-parameter of type reference to object, no
7660 conversions apply. The type referred to by the reference may be more
7661 cv-qualified than the (otherwise identical) type of the
7662 template-argument. The template-parameter is bound directly to the
7663 template-argument, which must be an lvalue. */
7665 {
7667 expr_type))
7671 {
7676 }
7679 {
7684 }
7686 /* [temp.arg.nontype]/1
7688 A template-argument for a non-type, non-template template-parameter
7689 shall be one of: [...]
7691 -- the address of an object or function with external linkage. */
7694 {
7697 {
7700 "because a reference variable does not have a constant "
7703 }
7704 }
7707 /* OK, dependent reference. We don't want to ask whether a DECL is
7709 else
7710 {
7715 }
7719 }
7720 /* [temp.arg.nontype]/5, bullet 4
7722 For a non-type template-parameter of type pointer to function, only
7723 the function-to-pointer conversion (_conv.func_) is applied. If the
7724 template-argument represents a set of overloaded functions (or a
7725 pointer to such), the matching function is selected from the set
7726 (_over.over_). */
7728 {
7729 /* If the argument is a template-id, we might not have enough
7730 context information to decay the pointer. */
7732 {
7736 }
7739 /* Null pointer values are OK in C++11. */
7745 }
7746 /* [temp.arg.nontype]/5, bullet 5
7748 For a non-type template-parameter of type reference to function, no
7749 conversions apply. If the template-argument represents a set of
7750 overloaded functions, the matching function is selected from the set
7751 (_over.over_). */
7753 {
7755 {
7757 {
7762 }
7764 }
7769 }
7770 /* [temp.arg.nontype]/5, bullet 6
7772 For a non-type template-parameter of type pointer to member function,
7773 no conversions apply. If the template-argument represents a set of
7774 overloaded member functions, the matching member function is selected
7775 from the set (_over.over_). */
7777 {
7782 /* [temp.arg.nontype] bullet 1 says the pointer to member
7783 expression must be a pointer-to-member constant. */
7788 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
7789 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
7792 }
7793 /* [temp.arg.nontype]/5, bullet 7
7795 For a non-type template-parameter of type pointer to data member,
7796 qualification conversions (_conv.qual_) are applied. */
7798 {
7799 /* [temp.arg.nontype] bullet 1 says the pointer to member
7800 expression must be a pointer-to-member constant. */
7808 }
7810 {
7812 {
7817 }
7819 }
7821 {
7822 /* Replace the argument with a reference to the corresponding template
7823 parameter object. */
7828 }
7829 /* A template non-type parameter must be one of the above. */
7830 else
7833 /* Sanity check: did we actually convert the argument to the
7834 right type? */
7838 }
7840 /* Subroutine of coerce_template_template_parms, which returns 1 if
7841 PARM_PARM and ARG_PARM match using the rule for the template
7842 parameters of template template parameters. Both PARM and ARG are
7843 template parameters; the rest of the arguments are the same as for
7844 coerce_template_template_parms.
7845 */
7846 static int
7848 tree arg,
7849 tsubst_flags_t complain,
7850 tree in_decl,
7851 tree outer_args)
7852 {
7861 {
7863 /* We encounter instantiations of templates like
7864 template <template <template <class> class> class TT>
7865 class C; */
7866 {
7870 }
7871 /* Fall through. */
7876 /* Argument is a parameter pack but parameter is not. */
7881 /* The tsubst call is used to handle cases such as
7883 template <int> class C {};
7884 template <class T, template <T> class TT> class D {};
7885 D<int, C> d;
7887 i.e. the parameter list of TT depends on earlier parameters. */
7889 {
7894 }
7898 /* Argument is a parameter pack but parameter is not. */
7905 }
7908 }
7910 /* Coerce template argument list ARGLIST for use with template
7911 template-parameter TEMPL. */
7913 static tree
7915 tsubst_flags_t complain)
7916 {
7917 /* Consider an example where a template template parameter declared as
7919 template <class T, class U = std::allocator<T> > class TT
7921 The template parameter level of T and U are one level larger than
7922 of TT. To proper process the default argument of U, say when an
7923 instantiation `TT<int>' is seen, we need to build the full
7924 arguments containing {int} as the innermost level. Outer levels,
7925 available when not appearing as default template argument, can be
7926 obtained from the arguments of the enclosing template.
7928 Suppose that TT is later substituted with std::vector. The above
7929 instantiation is `TT<int, std::allocator<T> >' with TT at
7930 level 1, and T at level 2, while the template arguments at level 1
7931 becomes {std::vector} and the inner level 2 is {int}. */
7937 {
7938 /* This is an argument of the current template, so we haven't set
7939 DECL_CONTEXT yet. We can also get here when level-lowering a
7940 bound ttp. */
7941 tree relevant_template_parms;
7943 /* Parameter levels that are greater than the level of the given
7944 template template parm are irrelevant. */
7951 }
7958 }
7960 /* A cache of template template parameters with match-all default
7961 arguments. */
7964 /* T is a bound template template-parameter. Copy its arguments into default
7965 arguments of the template template-parameter's template parameters. */
7967 static tree
7969 {
7992 {
7995 {
7998 }
7999 }
8003 tree gen_ntmpl;
8006 else
8016 }
8018 /* ARG is a bound potential template template-argument, and PARGS is a list
8019 of arguments for the corresponding template template-parameter. Adjust
8020 PARGS as appropriate for application to ARG's template, and if ARG is a
8021 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
8022 arguments to the template template parameter. */
8024 static tree
8026 {
8030 {
8031 /* When comparing two template template-parameters in partial ordering,
8032 rewrite the one currently being used as an argument to have default
8033 arguments for all parameters. */
8039 }
8040 else
8041 {
8042 tree aparms
8045 }
8048 }
8050 /* Subroutine of unify for the case when PARM is a
8051 BOUND_TEMPLATE_TEMPLATE_PARM. */
8053 static int
8056 {
8060 /* The template template parm might be variadic and the argument
8061 not, so flatten both argument lists. */
8066 {
8067 /* In keeping with P0522R0, adjust P's template arguments
8068 to apply to A's template; then flatten it again. */
8076 /* If the P0522 adjustment eliminated a pack expansion, deduce
8077 empty packs. */
8083 }
8084 else
8085 {
8086 /* Deduce arguments T, i from TT<T> or TT<i>.
8087 We check each element of PARMVEC and ARGVEC individually
8088 rather than the whole TREE_VEC since they can have
8089 different number of elements, which is allowed under N2555. */
8093 /* Check if the parameters end in a pack, making them
8094 variadic. */
8101 /* If the template argument list of P contains a pack
8102 expansion that is not the last template argument, the
8103 entire template argument list is a non-deduced
8104 context. */
8122 DEDUCE_EXACT,
8125 }
8128 }
8130 /* Return 1 if PARM_TMPL and ARG_TMPL match using rule for
8131 template template parameters.
8133 Consider the example:
8134 template <class T> class A;
8135 template<template <class U> class TT> class B;
8137 For B<A>, PARM_TMPL is TT, while ARG_TMPL is A,
8138 and OUTER_ARGS contains A. */
8140 static int
8142 tree arg_tmpl,
8143 tsubst_flags_t complain,
8144 tree in_decl,
8145 tree outer_args)
8146 {
8160 {
8161 /* P0522R0: A template template-parameter P is at least as specialized as
8162 a template template-argument A if, given the following rewrite to two
8163 function templates, the function template corresponding to P is at
8164 least as specialized as the function template corresponding to A
8165 according to the partial ordering rules for function templates
8166 ([temp.func.order]). Given an invented class template X with the
8167 template parameter list of A (including default arguments):
8169 * Each of the two function templates has the same template parameters,
8170 respectively, as P or A.
8172 * Each function template has a single function parameter whose type is
8173 a specialization of X with template arguments corresponding to the
8174 template parameters from the respective function template where, for
8175 each template parameter PP in the template parameter list of the
8176 function template, a corresponding template argument AA is formed. If
8177 PP declares a parameter pack, then AA is the pack expansion
8178 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
8180 If the rewrite produces an invalid type, then P is not at least as
8181 specialized as A. */
8183 /* So coerce P's args to apply to A's parms, and then deduce between A's
8184 args and the converted args. If that succeeds, A is at least as
8185 specialized as P, so they match.*/
8191 /* PARM and ARG might be at different template depths, and we want to
8192 pass the right additional levels of args when coercing PARGS to
8193 ARG_PARMS in case we need to do any substitution into non-type
8194 template parameter types.
8196 OUTER_ARGS are not the right outer levels in this case, as they are
8197 the args we're building up for PARM, and for the coercion we want the
8198 args for ARG. If DECL_CONTEXT isn't set for a template template
8199 parameter, we can assume that it's in the current scope. */
8207 {
8212 /* Only use as many levels from the scope as needed
8213 (excluding the level of ARG). */
8217 else
8220 /* Add the arguments that appear at the levels of ARG. */
8227 }
8228 else
8234 {
8240 }
8241 }
8243 /* Determine whether we have a parameter pack at the end of the
8244 template template parameter's template parameter list. */
8246 {
8253 {
8267 }
8268 }
8274 /* Check all of the template parameters except the parameter pack at
8275 the end (if any). */
8277 {
8286 outer_args))
8289 }
8292 {
8293 /* Check each of the template parameters in the template
8294 argument against the template parameter pack at the end of
8295 the template template parameter. */
8302 {
8309 outer_args))
8311 }
8312 }
8315 }
8317 /* Verifies that the deduced template arguments (in TARGS) for the
8318 template template parameters (in TPARMS) represent valid bindings,
8319 by comparing the template parameter list of each template argument
8320 to the template parameter list of its corresponding template
8321 template parameter, in accordance with DR150. This
8322 routine can only be called after all template arguments have been
8323 deduced. It will return TRUE if all of the template template
8324 parameter bindings are okay, FALSE otherwise. */
8325 bool
8327 {
8331 /* We're dealing with template parms in this process. */
8337 {
8342 {
8347 {
8348 /* Look inside the argument pack. */
8351 }
8354 {
8356 /* Extract the next argument from the argument
8357 pack. */
8361 /* Look at the pattern of the pack expansion. */
8364 /* Extract the template parameters from the template
8365 argument. */
8369 /* Verify that we can coerce the template template
8370 parameters from the template argument to the template
8371 parameter. This requires an exact match. */
8373 && !coerce_template_template_parms
8375 targ,
8376 tf_none,
8377 tparm,
8378 targs))
8379 {
8382 }
8383 }
8384 }
8385 }
8387 out:
8391 }
8393 /* Since type attributes aren't mangled, we need to strip them from
8394 template type arguments. */
8396 tree
8398 {
8408 }
8410 /* And from inside dependent non-type arguments like sizeof(Type). */
8412 static tree
8414 {
8424 }
8426 /* A template declaration can be substituted for a constrained
8427 template template parameter only when the argument is no more
8428 constrained than the parameter. */
8430 static bool
8432 {
8435 /* For now, allow constrained template template arguments
8436 and unconstrained template template parameters. */
8440 /* If the template parameter is constrained, we need to rewrite its
8441 constraints in terms of the ARG's template parameters. This ensures
8442 that all of the template parameter types will have the same depth.
8444 Note that this is only valid when coerce_template_template_parm is
8445 true for the innermost template parameters of PARM and ARG. In other
8446 words, because coercion is successful, this conversion will be valid. */
8449 {
8459 }
8462 }
8464 // Convert a placeholder argument into a binding to the original
8465 // parameter. The original parameter is saved as the TREE_TYPE of
8466 // ARG.
8469 {
8472 }
8474 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
8475 because one of them is dependent. But we need to represent the
8476 conversion for the benefit of cp_tree_equal. */
8478 static tree
8480 {
8481 /* Auto parms get no conversion. */
8484 /* ??? Do we need to push the IMPLICIT_CONV_EXPR into the pack expansion?
8485 That would complicate other things, and it doesn't seem necessary. */
8488 /* We don't need or want to add this conversion now if we're going to use the
8489 argument for deduction. */
8504 }
8506 /* Convert the indicated template ARG as necessary to match the
8507 indicated template PARM. Returns the converted ARG, or
8508 error_mark_node if the conversion was unsuccessful. Error and
8509 warning messages are issued under control of COMPLAIN. This
8510 conversion is for the Ith parameter in the parameter list. ARGS is
8511 the full set of template arguments deduced so far. */
8513 static tree
8515 tree arg,
8516 tree args,
8517 tsubst_flags_t complain,
8519 tree in_decl)
8520 {
8521 tree orig_arg;
8522 tree val;
8528 /* Trivially convert placeholders. */
8537 {
8538 /* The template argument was the name of some
8539 member function. That's usually
8540 invalid, but static members are OK. In any
8541 case, grab the underlying fields/functions
8542 and issue an error later if required. */
8544 }
8552 /* When determining whether an argument pack expansion is a template,
8553 look at the pattern. */
8557 /* Deal with an injected-class-name used as a template template arg. */
8559 {
8562 {
8572 }
8573 }
8575 is_tmpl_type =
8591 {
8593 {
8597 }
8600 "to refer to a type member of a template parameter, "
8605 typename_type,
8606 complain);
8609 }
8611 {
8613 {
8615 {
8620 {
8621 /* The template argument is a type, but we're expecting
8622 an expression. */
8627 /* [temp.arg]/2: "In a template-argument, an ambiguity
8628 between a type-id and an expression is resolved to a
8629 type-id, regardless of the form of the corresponding
8630 template-parameter." So give the user a clue. */
8633 "for non-type template parameter is treated as "
8635 }
8639 else
8642 }
8643 }
8645 }
8647 {
8649 {
8656 else
8659 }
8661 }
8664 /* We already did the appropriate conversion when packing args. */
8667 {
8669 {
8671 /* The number of argument required is not known yet.
8672 Just accept it for now. */
8674 else
8675 {
8676 /* Strip alias templates that are equivalent to another
8677 template. */
8682 args))
8683 {
8686 /* TEMPLATE_TEMPLATE_PARM node is preferred over
8687 TEMPLATE_DECL. */
8689 {
8694 }
8695 }
8696 else
8697 {
8699 {
8706 }
8709 }
8711 // Check that the constraints are compatible before allowing the
8712 // substitution.
8715 {
8717 {
8723 }
8725 }
8726 }
8727 }
8728 else
8730 /* We only form one instance of each template specialization.
8731 Therefore, if we use a non-canonical variant (i.e., a
8732 typedef), any future messages referring to the type will use
8733 the typedef, which is confusing if those future uses do not
8734 themselves also use the typedef. */
8737 }
8738 else
8739 {
8744 /* We don't have enough levels of args to do any substitution. This
8747 {
8752 }
8753 else
8756 /* Perform array-to-pointer and function-to-pointer conversion
8757 as per [temp.param]/10. */
8763 /* Drop top-level cv-qualifiers on the substituted/deduced type of
8764 this non-type template parameter, as per [temp.param]/6. */
8770 /* We need to handle arguments for alias or concept templates
8771 differently: we need to force building an IMPLICIT_CONV_EXPR, because
8772 these arguments are going to be substituted directly into the
8773 dependent type; they might not get another chance at
8774 convert_nontype_argument. But if the argument ends up here again for
8775 a template that isn't one of those, remove the conversion for
8776 consistency between naming the same dependent type directly or through
8777 an alias. */
8788 /* We used to call digest_init here. However, digest_init
8789 will report errors, which we don't want when complain
8790 is zero. More importantly, digest_init will try too
8791 hard to convert things: for example, `0' should not be
8792 converted to pointer type at this point according to
8793 the standard. Accepting this is not merely an
8794 extension, since deciding whether or not these
8795 conversions can occur is part of determining which
8796 function template to call, or whether a given explicit
8797 argument specification is valid. */
8799 else
8800 {
8803 }
8813 {
8814 /* Reject template arguments that are references to built-in
8815 functions with no library fallbacks. */
8824 }
8827 {
8828 /* Strip typedefs from the SCOPE_REF. */
8831 complain);
8834 }
8835 }
8838 }
8840 /* Coerces the remaining template arguments in INNER_ARGS (from
8841 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
8842 Returns the coerced argument pack. PARM_IDX is the position of this
8843 parameter in the template parameter list. ARGS is the original
8844 template argument list. */
8845 static tree
8848 tree args,
8849 tree inner_args,
8851 tree new_args,
8853 tree in_decl,
8854 tsubst_flags_t complain)
8855 {
8858 tree packed_args;
8859 tree argument_pack;
8866 {
8867 /* When the template parameter is a non-type template parameter pack
8868 or template template parameter pack whose type or template
8869 parameters use parameter packs, we know exactly how many arguments
8870 we are looking for. Build a vector of the instantiated decls for
8871 these template parameters in PACKED_PARMS. */
8872 /* We can't use make_pack_expansion here because it would interpret a
8873 _DECL as a use rather than a declaration. */
8887 /* If we're doing a partial instantiation of a member template,
8888 verify that all of the types used for the non-type
8889 template parameter pack are, in fact, valid for non-type
8890 template parameters. */
8893 {
8896 {
8901 }
8902 /* We don't know how many args we have yet, just
8903 use the unconverted ones for now. */
8905 }
8908 }
8909 /* Check if we have a placeholder pack, which indicates we're
8910 in the context of a introduction list. In that case we want
8911 to match this pack to the single placeholder. */
8915 {
8918 }
8919 else
8922 /* Convert the remaining arguments, which will be a part of the
8923 parameter pack "parm". */
8926 {
8932 {
8933 /* Once we've packed as many args as we have types, stop. */
8937 /* We don't know how many args we have yet, just
8938 use the unconverted ones for now. */
8940 else
8942 }
8945 {
8948 }
8949 else
8952 in_decl);
8956 }
8960 {
8965 }
8970 else
8971 {
8974 }
8981 }
8983 /* Returns the number of pack expansions in the template argument vector
8984 ARGS. */
8986 static int
8988 {
8993 {
8997 }
8999 }
9001 /* Convert all template arguments to their appropriate types, and
9002 return a vector containing the innermost resulting template
9003 arguments. If any error occurs, return error_mark_node. Error and
9004 warning messages are issued under control of COMPLAIN.
9006 If PARMS represents all template parameters levels, this function
9007 returns a vector of vectors representing all the resulting argument
9008 levels. Note that in this case, only the innermost arguments are
9009 coerced because the outermost ones are supposed to have been coerced
9010 already. Otherwise, if PARMS represents only (the innermost) vector
9011 of parameters, this function returns a vector containing just the
9012 innermost resulting arguments.
9014 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
9015 for arguments not specified in ARGS. If REQUIRE_ALL_ARGS is true,
9016 arguments not specified in ARGS must have default arguments which
9017 we'll use to fill in ARGS. */
9019 tree
9021 tree args,
9022 tree in_decl,
9023 tsubst_flags_t complain,
9025 {
9027 tree orig_inner_args;
9028 tree inner_args;
9030 /* When used as a boolean value, indicates whether this is a
9031 variadic template parameter list. Since it's an int, we can also
9032 subtract it from nparms to get the number of non-variadic
9033 parameters. */
9038 /* Adjustment to nparms for fixed parameter packs. */
9043 /* Likewise for parameters with default arguments. */
9051 {
9053 {
9056 }
9058 }
9062 /* Determine if there are any parameter packs or default arguments. */
9064 {
9072 }
9075 /* If there are no parameters that follow a parameter pack, we need to
9076 expand any argument packs so that we can deduce a parameter pack from
9077 some non-packed args followed by an argument pack, as in variadic85.C.
9078 If there are such parameters, we need to leave argument packs intact
9079 so the arguments are assigned properly. This can happen when dealing
9080 with a nested class inside a partial specialization of a class
9081 template, as in variadic92.C, or when deducing a template parameter pack
9082 from a sub-declarator, as in variadic114.C. */
9086 /* Count any pack expansion args. */
9092 && require_all_args
9093 && !variadic_args_p
9096 {
9097 bad_nargs:
9099 {
9101 {
9105 }
9106 else
9113 }
9116 }
9117 /* We can't pass a pack expansion to a non-pack parameter of an alias
9118 template (DR 1430). */
9122 && variadic_args_p
9124 {
9126 {
9128 {
9134 {
9137 "pack expansion argument for non-pack parameter "
9139 else
9141 "pack expansion argument for non-pack parameter "
9145 }
9146 }
9148 found:;
9149 }
9151 }
9153 /* We need to evaluate the template arguments, even though this
9154 template-id may be nested within a "sizeof". */
9155 cp_evaluated ev;
9161 {
9162 tree arg;
9163 tree parm;
9165 /* Get the Ith template parameter. */
9169 {
9172 }
9174 /* Calculate the next argument. */
9177 else
9183 {
9184 /* Some arguments will be placed in the
9185 template parameter pack PARM. */
9192 {
9193 /* We don't know how many args we have yet, just use the
9194 unconverted (and still packed) ones for now. */
9198 }
9202 /* Store this argument. */
9204 {
9205 lost++;
9206 /* We are done with all of the arguments. */
9209 }
9210 else
9211 {
9215 {
9218 }
9219 }
9222 }
9224 {
9226 {
9227 /* "If every valid specialization of a variadic template
9228 requires an empty template parameter pack, the template is
9229 ill-formed, no diagnostic required." So check that the
9230 pattern works with this parameter. */
9235 in_decl);
9237 {
9242 }
9244 /* Recover from missing typename. */
9248 /* We don't know how many args we have yet, just
9249 use the unconverted ones for now. */
9253 }
9254 }
9256 {
9257 /* There must be a default arg in this case. */
9260 /* The position of the first default template argument,
9261 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
9262 Record that. */
9266 }
9267 else
9271 {
9274 }
9276 {
9277 /* This can occur if there was an error in the template
9278 parameter list itself (which we would already have
9279 reported) that we are trying to recover from, e.g., a class
9280 template with a parameter list such as
9281 template<typename..., typename> (cpp0x/variadic150.C). */
9284 /* This can also happen with a fixed parameter pack (71834). */
9287 }
9288 else
9294 lost++;
9297 }
9300 {
9301 /* If we had fixed parameter packs, we didn't know how many arguments we
9302 actually needed earlier; now we do. */
9306 }
9309 {
9310 /* We had some pack expansion arguments that will only work if the packs
9311 are empty, but wait until instantiation time to complain.
9312 See variadic-ttp3.C. */
9314 /* Except that we can't provide empty packs to alias templates or
9315 concepts when there are no corresponding parameters. Basically,
9316 we can get here with this:
9318 template<typename T> concept C = true;
9320 template<typename... Args>
9321 requires C<Args...>
9322 void f();
9324 When parsing C<Args...>, we try to form a concept check of
9325 C<?, Args...>. Without the extra check for substituting an empty
9326 pack past the last parameter, we can accept the check as valid.
9328 FIXME: This may be valid for alias templates (but I doubt it).
9330 FIXME: The error could be better also. */
9332 {
9337 }
9348 }
9351 {
9354 }
9361 }
9363 /* Returns true if T is a wrapper to make a C++20 template parameter
9364 object const. */
9366 static bool
9368 {
9374 }
9376 /* Returns 1 if template args OT and NT are equivalent. */
9378 int
9380 {
9393 /* DR 1558: Don't treat an alias template specialization with dependent
9394 arguments as equivalent to its underlying type when used as a template
9395 argument; we need them to be distinct so that we substitute into the
9396 specialization arguments at instantiation time. And aliases can't be
9397 equivalent without being ==, so we don't need to look any deeper.
9399 During partial ordering, however, we need to treat them normally so we can
9400 order uses of the same alias with different cv-qualification (79960). */
9406 /* For member templates */
9419 {
9423 }
9424 else
9425 {
9426 /* Try to treat a template non-type argument that has been converted
9427 to the parameter type as equivalent to one that hasn't yet. */
9441 }
9442 }
9444 /* Returns true iff the OLDARGS and NEWARGS are in fact identical sets of
9445 template arguments. Returns false otherwise, and updates OLDARG_PTR and
9446 NEWARG_PTR with the offending arguments if they are non-NULL. */
9448 bool
9451 {
9462 {
9467 {
9473 }
9474 }
9476 }
9478 static bool
9480 {
9485 }
9487 /* Implement a freelist interface for objects of type T.
9489 Head is a separate object, rather than a regular member, so that we
9490 can define it as a GTY deletable pointer, which is highly
9491 desirable. A data member could be declared that way, but then the
9492 containing object would implicitly get GTY((user)), which would
9493 prevent us from instantiating freelists as global objects.
9494 Although this way we can create freelist global objects, they're
9495 such thin wrappers that instantiating temporaries at every use
9496 loses nothing and saves permanent storage for the freelist object.
9498 Member functions next, anew, poison and reinit have default
9499 implementations that work for most of the types we're interested
9500 in, but if they don't work for some type, they should be explicitly
9501 specialized. See the comments before them for requirements, and
9502 the example specializations for the tree_list_freelist. */
9504 class freelist
9505 {
9506 /* Return the next object in a chain. We could just do type
9507 punning, but if we access the object with its underlying type, we
9508 avoid strict-aliasing trouble. This needs only work between
9509 poison and reinit. */
9512 /* Return a newly allocated, uninitialized or minimally-initialized
9513 object of type T. Any initialization performed by anew should
9514 either remain across the life of the object and the execution of
9515 poison, or be redone by reinit. */
9518 /* Optionally scribble all over the bits holding the object, so that
9519 they become (mostly?) uninitialized memory. This is called while
9520 preparing to make the object part of the free list. */
9525 #ifdef ENABLE_GC_CHECKING
9526 /* Poison the data, to indicate the data is garbage. */
9529 #endif
9530 /* Let valgrind know the object is free. */
9533 /* Let valgrind know the next portion of the object is available,
9534 but uninitialized. */
9536 }
9538 /* Bring an object that underwent at least one lifecycle after anew
9539 and before the most recent free and poison, back to a usable
9540 state, reinitializing whatever is needed for it to be
9541 functionally equivalent to an object just allocated and returned
9542 by anew. This may poison or clear the next field, used by
9543 freelist housekeeping after poison was called. */
9547 #ifdef ENABLE_GC_CHECKING
9549 #endif
9550 /* Let valgrind know the entire object is available, but
9551 uninitialized. */
9553 }
9555 /* Reference a GTY-deletable pointer that points to the first object
9556 in the free list proper. */
9559 /* Construct a freelist object chaining objects off of HEAD. */
9562 /* Add OBJ to the free object list. The former head becomes OBJ's
9563 successor. */
9565 {
9569 }
9571 /* Take an object from the free list, if one is available, or
9572 allocate a new one. Objects taken from the free list should be
9573 regarded as filled with garbage, except for bits that are
9574 configured to be preserved across free and alloc. */
9576 {
9578 {
9583 }
9584 else
9586 }
9587 };
9589 /* Explicitly specialize the interfaces for freelist<tree_node>: we
9590 want to allocate a TREE_LIST using the usual interface, and ensure
9591 TREE_CHAIN remains functional. Alas, we have to duplicate a bit of
9592 build_tree_list logic in reinit, so this could go out of sync. */
9596 {
9598 }
9600 inline tree
9602 {
9604 }
9608 {
9614 #ifdef ENABLE_GC_CHECKING
9617 /* Poison the data, to indicate the data is garbage. */
9620 #endif
9621 /* Let valgrind know the object is free. */
9623 /* But we still want to use the TREE_CODE and TREE_CHAIN parts. */
9627 #ifdef ENABLE_GC_CHECKING
9629 /* Keep TREE_CHAIN functional. */
9631 #else
9633 #endif
9634 }
9638 {
9641 #ifdef ENABLE_GC_CHECKING
9645 #endif
9647 /* Let valgrind know the entire object is available, but
9648 uninitialized. */
9651 #ifdef ENABLE_GC_CHECKING
9653 #else
9656 #endif
9658 }
9660 /* Point to the first object in the TREE_LIST freelist. */
9662 /* Return the/an actual TREE_LIST freelist. */
9665 {
9667 }
9669 /* Point to the first object in the tinst_level freelist. */
9671 /* Return the/an actual tinst_level freelist. */
9674 {
9676 }
9678 /* Point to the first object in the pending_template freelist. */
9680 /* Return the/an actual pending_template freelist. */
9683 {
9685 }
9687 /* Build the TREE_LIST object out of a split list, store it
9688 permanently, and return it. */
9689 tree
9691 {
9700 }
9704 /* Increment OBJ's refcount unless it is already infinite. */
9707 {
9711 }
9713 /* Release storage for OBJ and node, if it's a TREE_LIST. */
9714 void
9716 {
9720 }
9722 /* Decrement OBJ's refcount if not infinite. If it reaches zero, release
9723 OBJ's DECL and OBJ, and start over with the tinst_level object that
9724 used to be referenced by OBJ's NEXT. */
9725 static void
9727 {
9731 {
9735 }
9736 }
9738 /* Modify PTR so that it points to OBJ, adjusting the refcounts of OBJ
9739 and of the former PTR. Omitting the second argument is equivalent
9740 to passing (T*)NULL; this is allowed because passing the
9741 zero-valued integral constant NULL confuses type deduction and/or
9742 overload resolution. */
9744 static void
9746 {
9750 }
9752 static void
9754 {
9764 /* We are called both from instantiate_decl, where we've already had a
9765 tinst_level pushed, and instantiate_template, where we haven't.
9766 Compensate. */
9768 level = !current_tinst_level
9780 else
9789 }
9792 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
9793 ARGLIST. Valid choices for FNS are given in the cp-tree.def
9794 documentation for TEMPLATE_ID_EXPR. */
9796 tree
9798 {
9805 {
9808 }
9811 {
9814 unknown_type_node,
9816 arglist);
9818 }
9821 }
9823 /* Within the scope of a template class S<T>, the name S gets bound
9824 (in build_self_reference) to a TYPE_DECL for the class, not a
9825 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
9826 or one of its enclosing classes, and that type is a template,
9827 return the associated TEMPLATE_DECL. Otherwise, the original
9828 DECL is returned.
9830 Also handle the case when DECL is a TREE_LIST of ambiguous
9831 injected-class-names from different bases. */
9833 tree
9835 {
9839 /* DR 176: A lookup that finds an injected-class-name (10.2
9840 [class.member.lookup]) can result in an ambiguity in certain cases
9841 (for example, if it is found in more than one base class). If all of
9842 the injected-class-names that are found refer to specializations of
9843 the same class template, and if the name is followed by a
9844 template-argument-list, the reference refers to the class template
9845 itself and not a specialization thereof, and is not ambiguous. */
9847 {
9850 {
9856 }
9859 else
9861 }
9867 }
9869 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
9870 parameters, find the desired type.
9872 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
9874 IN_DECL, if non-NULL, is the template declaration we are trying to
9875 instantiate.
9877 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
9878 the class we are looking up.
9880 Issue error and warning messages under control of COMPLAIN.
9882 If the template class is really a local class in a template
9883 function, then the FUNCTION_CONTEXT is the function in which it is
9884 being instantiated.
9886 ??? Note that this function is currently called *twice* for each
9887 template-id: the first time from the parser, while creating the
9888 incomplete type (finish_template_type), and the second type during the
9889 real instantiation (instantiate_template_class). This is surely something
9890 that we want to avoid. It also causes some problems with argument
9891 coercion (see convert_nontype_argument for more information on this). */
9893 tree
9896 {
9900 tree t;
9903 spec_entry elt;
9904 hashval_t hash;
9907 {
9911 else
9912 {
9919 }
9920 }
9922 {
9925 /* If we are declaring a constructor, say A<T>::A<T>, we will get
9926 an implicit typename for the second A. Deal with it. */
9931 {
9934 }
9935 }
9938 {
9941 }
9943 {
9946 }
9948 {
9951 }
9953 /* Issue an error message if we didn't find a template. */
9955 {
9959 }
9962 /* Make sure it's a user visible template, if it was named by
9963 the user. */
9966 {
9968 {
9972 }
9974 }
9978 /* An alias that just changes the name of a template is equivalent to the
9979 other template, so if any of the arguments are pack expansions, strip
9980 the alias to avoid problems with a pack expansion passed to a non-pack
9981 alias template parameter (DR 1430). */
9986 {
9987 tree parm;
9996 }
9997 else
9998 {
10000 tree gen_tmpl;
10001 tree type_decl;
10009 /* An error occurred while building the template TEMPL, and a
10010 diagnostic has most certainly been emitted for that
10011 already. Let's propagate that error. */
10023 {
10024 /* We've been given an incomplete set of template arguments.
10025 For example, given:
10027 template <class T> struct S1 {
10028 template <class U> struct S2 {};
10029 template <class U> struct S2<U*> {};
10030 };
10032 we will be called with an ARGLIST of `U*', but the
10033 TEMPLATE will be `template <class T> template
10034 <class U> struct S1<T>::S2'. We must fill in the missing
10035 arguments. */
10039 }
10041 /* Now we should have enough arguments. */
10044 /* From here on, we're only interested in the most general
10045 template. */
10047 /* Shortcut looking up the current class scope again. */
10051 {
10062 }
10064 /* Calculate the BOUND_ARGS. These will be the args that are
10065 actually tsubst'd into the definition to create the
10066 instantiation. */
10071 /* We were unable to bind the arguments. */
10074 /* In the scope of a template class, explicit references to the
10075 template class refer to the type of the template, not any
10076 instantiation of it. For example, in:
10078 template <class T> class C { void f(C<T>); }
10080 the `C<T>' is just the same as `C'. Outside of the
10081 class, however, such a reference is an instantiation. */
10085 {
10090 }
10092 /* If we already have this specialization, return it. */
10102 /* If the template's constraints are not satisfied,
10103 then we cannot form a valid type.
10105 Note that the check is deferred until after the hash
10106 lookup. This prevents redundant checks on previously
10107 instantiated specializations. */
10111 {
10113 {
10114 auto_diagnostic_group d;
10117 }
10119 }
10123 /* If the deduced arguments are invalid, then the binding
10124 failed. */
10128 complain))
10135 /* This occurs when the user has tried to define a tagged type
10136 in a scope that forbids it. We emitted an error during the
10137 parse. We didn't complete the bail out then, so here we
10138 are. */
10143 {
10145 /* If the context of the partially instantiated template is
10146 already non-dependent, then we might as well use it. */
10148 else
10149 {
10152 /* Try completing the enclosing context if it's not already so. */
10155 {
10158 {
10159 /* Completion could have caused us to register the desired
10160 specialization already, so check the table again. */
10164 }
10165 }
10166 }
10167 }
10168 else
10177 /* Create the type. */
10179 {
10180 /* The user referred to a specialization of an alias
10181 template represented by GEN_TMPL.
10183 [temp.alias]/2 says:
10185 When a template-id refers to the specialization of an
10186 alias template, it is equivalent to the associated
10187 type obtained by substitution of its
10188 template-arguments for the template-parameters in the
10189 type-id of the alias template. */
10192 /* Note that the call above (by indirectly calling
10193 register_specialization in tsubst_decl) registers the
10194 TYPE_DECL representing the specialization of the alias
10195 template. So next time someone substitutes ARGLIST for
10196 the template parms into the alias template (GEN_TMPL),
10197 she'll get that TYPE_DECL back. */
10201 }
10203 {
10205 {
10216 }
10217 else
10218 {
10219 /* We don't want to call start_enum for this type, since
10220 the values for the enumeration constants may involve
10221 template parameters. And, no one should be interested
10222 in the enumeration constants for such a type. */
10225 }
10229 }
10231 {
10232 /* Lambda closures are regenerated in tsubst_lambda_expr, not
10233 instantiated here. */
10241 /* A local class. Make sure the decl gets registered properly. */
10248 /* This instantiation is another name for the primary
10249 template type. Set the TYPE_CANONICAL field
10250 appropriately. */
10254 }
10255 else
10258 /* If we called start_enum or pushtag above, this information
10259 will already be set up. */
10262 {
10269 }
10272 /* Although GEN_TMPL is the TEMPLATE_DECL, it has the same value
10273 of export flag. We want to propagate this because it might
10274 be a friend declaration that pushes a new hidden binding. */
10278 {
10284 {
10287 }
10288 }
10292 {
10296 {
10297 tree attributes
10305 }
10306 }
10308 /* Let's consider the explicit specialization of a member
10309 of a class template specialization that is implicitly instantiated,
10310 e.g.:
10311 template<class T>
10312 struct S
10313 {
10314 template<class U> struct M {}; //#0
10315 };
10317 template<>
10318 template<>
10319 struct S<int>::M<char> //#1
10320 {
10321 int i;
10322 };
10323 [temp.expl.spec]/4 says this is valid.
10325 In this case, when we write:
10326 S<int>::M<char> m;
10328 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
10329 the one of #0.
10331 When we encounter #1, we want to store the partial instantiation
10332 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
10334 For all cases other than this "explicit specialization of member of a
10335 class template", we just want to store the most general template into
10336 the CLASSTYPE_TI_TEMPLATE of M.
10338 This case of "explicit specialization of member of a class template"
10339 only happens when:
10340 1/ the enclosing class is an instantiation of, and therefore not
10341 the same as, the context of the most general template, and
10342 2/ we aren't looking at the partial instantiation itself, i.e.
10343 the innermost arguments are not the same as the innermost parms of
10344 the most general template.
10346 So it's only when 1/ and 2/ happens that we want to use the partial
10347 instantiation of the member template in lieu of its most general
10348 template. */
10352 /* the enclosing class must be an instantiation... */
10355 {
10359 tree partial_inst_args =
10366 use_partial_inst_tmpl =
10367 /*...and we must not be looking at the partial instantiation
10368 itself. */
10370 partial_inst_args);
10371 }
10374 /* This case is easy; there are no member templates involved. */
10376 else
10377 {
10378 /* This is a full instantiation of a member template. Find
10379 the partial instantiation of which this is an instance. */
10381 /* Temporarily reduce by one the number of levels in the ARGLIST
10382 so as to avoid comparing the last set of arguments. */
10384 /* We don't use COMPLAIN in the following call because this isn't
10385 the immediate context of deduction. For instance, tf_partial
10386 could be set here as we might be at the beginning of template
10387 argument deduction when any explicitly specified template
10388 arguments are substituted into the function type. tf_partial
10389 could lead into trouble because we wouldn't find the partial
10390 instantiation that might have been created outside tf_partial
10391 context, because the levels of template parameters wouldn't
10392 match, because in a tf_partial context, tsubst doesn't reduce
10393 TEMPLATE_PARM_LEVEL. */
10396 /* FOUND is either a proper class type, or an alias
10397 template specialization. In the later case, it's a
10398 TYPE_DECL, resulting from the substituting of arguments
10399 for parameters in the TYPE_DECL of the alias template
10400 done earlier. So be careful while getting the template
10401 of FOUND. */
10403 ? found
10410 {
10411 /* If this partial instantiation is specialized, we want to
10412 use it for hash table lookup. */
10416 }
10417 }
10419 /* Build template info for the new specialization. */
10429 /* Note this use of the partial instantiation so we can check it
10430 later in maybe_process_partial_specialization. */
10438 /* Now that the type has been registered on the instantiations
10439 list, we set up the enumerators. Because the enumeration
10440 constants may involve the enumeration type itself, we make
10441 sure to register the type first, and then create the
10442 constants. That way, doing tsubst_expr for the enumeration
10443 constants won't result in recursive calls here; we'll find
10444 the instantiation and exit above. */
10448 /* If the type makes use of template parameters, the
10449 code that generates debugging information will crash. */
10452 /* Possibly limit visibility based on template args. */
10459 }
10460 }
10462 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
10464 tree
10466 {
10477 /* The type of the expression is NULL_TREE since the template-id could refer
10478 to an explicit or partial specialization. */
10480 }
10482 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR if it's
10483 not dependent. */
10485 tree
10487 {
10491 /* If the template or arguments are dependent, then we
10492 can't resolve the TEMPLATE_ID_EXPR yet. */
10498 {
10500 {
10501 auto_diagnostic_group d;
10504 }
10506 }
10509 }
10511 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
10512 TARGS template args, and instantiate it if it's not dependent. */
10514 tree
10516 tsubst_flags_t complain)
10517 {
10524 }
10526 /* If the set of template parameters PARMS contains a template parameter
10527 at the given LEVEL and INDEX, then return this parameter. Otherwise
10528 return NULL_TREE. */
10530 static tree
10532 {
10541 }
10543 /* Return the TREE_LIST for the template parameter from PARMS that positionally
10544 corresponds to the template parameter PARM, or else return NULL_TREE. */
10546 static tree
10548 {
10552 }
10554 /* As above, but pull out the actual parameter. */
10556 static tree
10558 {
10564 /* As in template_parm_to_arg. */
10567 else
10572 }
10573 \f
10574 struct pair_fn_data
10575 {
10576 tree_fn_t fn;
10577 tree_fn_t any_fn;
10579 /* True when we should also visit template parameters that occur in
10580 non-deduced contexts. */
10583 };
10585 /* Called from for_each_template_parm via walk_tree. */
10587 static tree
10589 {
10596 #define WALK_SUBTREE(NODE) \
10597 do \
10598 { \
10599 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
10600 pfd->include_nondeduced_p, \
10601 pfd->any_fn); \
10602 if (result) goto out; \
10603 } \
10604 while (0)
10614 {
10618 /* Fall through. */
10624 else
10634 /* Since we're not going to walk subtrees, we have to do this
10635 explicitly here. */
10637 /* Fall through. */
10640 /* Check the return type. */
10643 /* Check the parameter types. Since default arguments are not
10644 instantiated until they are needed, the TYPE_ARG_TYPES may
10645 contain expressions that involve template parameters. But,
10646 no-one should be looking at them yet. And, once they're
10647 instantiated, they don't contain template parameters, so
10648 there's no point in looking at them then, either. */
10649 {
10650 tree parm;
10655 /* Since we've already handled the TYPE_ARG_TYPES, we don't
10656 want walk_tree walking into them itself. */
10658 }
10661 {
10665 }
10681 {
10684 }
10707 /* Record template parameters such as `T' inside `TT<T>'. */
10709 /* Fall through. */
10721 /* A template template parameter is encountered. */
10725 /* Already substituted template template parameter */
10730 /* A template-id in a TYPENAME_TYPE might be a deduced context after
10731 partial instantiation. */
10738 /* If there's no type, then this thing must be some expression
10739 involving template parameters. */
10749 /* These are non-deduced contexts. */
10771 }
10773 #undef WALK_SUBTREE
10775 /* We didn't find any template parameters we liked. */
10776 out:
10778 }
10780 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
10781 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
10782 call FN with the parameter and the DATA.
10783 If FN returns nonzero, the iteration is terminated, and
10784 for_each_template_parm returns 1. Otherwise, the iteration
10785 continues. If FN never returns a nonzero value, the value
10786 returned by for_each_template_parm is 0. If FN is NULL, it is
10787 considered to be the function which always returns 1.
10789 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
10790 parameters that occur in non-deduced contexts. When false, only
10791 visits those template parameters that can be deduced. */
10793 static tree
10797 tree_fn_t any_fn)
10798 {
10800 tree result;
10802 /* Set up. */
10808 /* Walk the tree. (Conceptually, we would like to walk without
10809 duplicates, but for_each_template_parm_r recursively calls
10810 for_each_template_parm, so we would need to reorganize a fair
10811 bit to use walk_tree_without_duplicates, so we keep our own
10812 visited list.) */
10815 else
10818 for_each_template_parm_r,
10822 /* Clean up. */
10824 {
10827 }
10830 }
10832 struct find_template_parameter_info
10833 {
10837 {}
10843 tree ctx_parms;
10850 };
10852 /* Appends the declaration of T to the list in DATA. */
10854 static int
10856 {
10859 /* Template parameters declared within the expression are not part of
10860 the parameter mapping. For example, in this concept:
10862 template<typename T>
10863 concept C = requires { <expr> } -> same_as<int>;
10865 the return specifier same_as<int> declares a new decltype parameter
10866 that must not be part of the parameter mapping. The same is true
10867 for generic lambda parameters, lambda template parameters, etc. */
10875 /* We want the underlying TEMPLATE_TEMPLATE_PARM, not the
10876 BOUND_TEMPLATE_TEMPLATE_PARM itself. */
10879 /* This template parameter might be an argument to a cached dependent
10880 specalization that was formed earlier inside some other template, in
10881 which case the parameter is not among the ones that are in-scope.
10882 Look in CTX_PARMS to find the corresponding in-scope template
10883 parameter, and use it instead. */
10887 /* Arguments like const T yield parameters like const T. This means that
10888 a template-id like X<T, const T> would yield two distinct parameters:
10889 T and const T. Adjust types to their unqualified versions. */
10893 {
10894 /* Append T to PARM_LIST. */
10898 }
10900 /* Verify the parameter we found has a valid index. */
10902 {
10908 }
10911 }
10913 /* Ensure that we recursively examine certain terms that are not normally
10914 visited in for_each_template_parm_r. */
10916 static int
10918 {
10921 #define WALK_SUBTREE(NODE) \
10922 do \
10923 { \
10924 for_each_template_parm (NODE, keep_template_parm, data, \
10925 &ftpi->visited, true, \
10926 any_template_parm_r); \
10927 } \
10928 while (0)
10930 /* A mention of a member alias/typedef is a use of all of its template
10931 arguments, including those from the enclosing class, so we don't use
10932 alias_template_specialization_p here. */
10938 {
10940 /* Type constraints of a placeholder type may contain parameters. */
10947 /* Search through references to variable templates. */
10957 /* If T is a member template that shares template parameters with
10958 ctx_parms, we need to mark all those parameters for mapping.
10959 To that end, it should suffice to just walk the DECL_CONTEXT of
10960 the template (assuming the template is not overly general). */
10965 {
10966 /* Look in the parms and body. */
10970 }
10975 /* The conversion-type-id of a conversion operator may be dependent. */
10986 }
10988 /* Keep walking. */
10990 }
10992 /* Look through T for template parameters. */
10994 tree
10996 {
10999 any_template_parm_r);
11000 }
11002 /* As above, but also recursively look into the default arguments of template
11003 parameters we found. Used for alias CTAD. */
11005 tree
11007 {
11010 /* Since newly found parms are added to the end of the list, we
11011 can just walk it until we reach the end. */
11013 {
11018 }
11020 }
11022 /* True if PARM was found by a previous call to find_in. PARM can be a
11023 TREE_LIST, a DECL_TEMPLATE_PARM_P, or a TEMPLATE_PARM_P. */
11025 bool
11027 {
11032 else
11036 }
11038 /* Returns a list of unique template parameters found within T, where CTX_PARMS
11039 are the template parameters in scope. */
11041 tree
11043 {
11050 }
11052 /* Returns true if T depends on any template parameter. */
11054 bool
11056 {
11060 /* Namespaces can't depend on any template parameters. */
11076 else
11078 }
11080 /* Returns true if T depends on any template parameter with level LEVEL. */
11082 bool
11084 {
11087 }
11089 /* Returns true if the signature of DECL depends on any template parameter from
11090 its enclosing class. */
11092 static bool
11094 {
11098 else
11107 {
11110 {
11115 template_parm_outer_level,
11125 }
11126 }
11130 }
11132 /* Returns true if the constraints of DECL depend on any template parameters
11133 from its enclosing scope. */
11135 bool
11137 {
11144 {
11147 else
11149 }
11155 }
11157 /* Returns TRUE iff INST is an instantiation we don't need to do in an
11158 ill-formed translation unit, i.e. a variable or function that isn't
11159 usable in a constant expression. */
11163 {
11169 }
11171 /* Returns TRUE iff we should refuse to instantiate DECL because it's
11172 neglectable and instantiated from within an erroneous instantiation. */
11174 static bool
11176 {
11182 /* Avoid instantiating members of an ill-formed class. */
11183 bool refuse
11188 {
11193 }
11196 {
11197 /* Don't warn about it not being defined. */
11199 tree clone;
11202 }
11204 }
11212 /* We're starting to instantiate D; record the template instantiation context
11213 at LOC for diagnostics and to restore it later. */
11215 bool
11217 {
11221 {
11222 /* Tell error.cc not to try to instantiate any templates. */
11225 "template instantiation depth exceeds maximum of %d"
11227 max_tinst_depth);
11229 }
11231 /* If the current instantiation caused problems, don't let it instantiate
11232 anything else. Do allow deduction substitution and decls usable in
11233 constant expressions. */
11235 {
11236 /* Avoid no_linkage_errors and unused function (and all other)
11237 warnings for this decl. */
11240 }
11242 /* When not -quiet, dump template instantiations other than functions, since
11243 announce_function will take care of those. */
11265 }
11267 /* We're starting substitution of TMPL<ARGS>; record the template
11268 substitution context for diagnostics and to restore it later. */
11270 bool
11272 {
11274 }
11276 /* We're starting to instantiate D; record INPUT_LOCATION and the
11277 template instantiation context for diagnostics and to restore it
11278 later. */
11280 bool
11282 {
11284 }
11286 /* Likewise, but record LOC as the program location. */
11288 bool
11290 {
11293 }
11295 /* We're done instantiating this template; return to the instantiation
11296 context. */
11298 void
11300 {
11301 /* Restore the filename and line number stashed away when we started
11302 this instantiation. */
11306 }
11308 /* We're instantiating a deferred template; restore the template
11309 instantiation context in which the instantiation was requested, which
11310 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
11312 static tree
11314 {
11326 }
11328 /* Returns the TINST_LEVEL which gives the original instantiation
11329 context. */
11333 {
11339 }
11341 /* True iff T is a friend function declaration that is not itself a template
11342 and is not defined in a class template. */
11344 bool
11346 {
11349 {
11353 /* DECL_FRIEND_CONTEXT is set for a friend defined in class. */
11356 /* Non-templated friends in a class template are still represented with a
11357 TEMPLATE_DECL; check that its primary template is the befriending
11358 class. Note that DECL_PRIMARY_TEMPLATE is null for
11359 template <class T> friend A<T>::f(); */
11363 }
11364 else
11366 }
11368 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
11369 vector of template arguments, as for tsubst.
11371 Returns an appropriate tsubst'd friend declaration. */
11373 static tree
11375 {
11376 tree new_friend;
11381 /* This was a friend declared with an explicit template
11382 argument list, e.g.:
11384 friend void f<>(T);
11386 to indicate that f was a template instantiation, not a new
11387 function declaration. Now, we have to figure out what
11388 instantiation of what template. */
11389 {
11391 tree new_args;
11392 tree tmpl;
11395 /* Friend functions are looked up in the containing namespace scope.
11396 We must enter that scope, to avoid finding member functions of the
11397 current class with same name. */
11411 tsk_none);
11413 }
11419 /* The NEW_FRIEND will look like an instantiation, to the
11420 compiler, but is not an instantiation from the point of view of
11421 the language. For example, we might have had:
11423 template <class T> struct S {
11424 template <class U> friend void f(T, U);
11425 };
11427 Then, in S<int>, template <class U> void f(int, U) is not an
11428 instantiation of anything. */
11432 {
11438 /* Substitute TEMPLATE_PARMS_CONSTRAINTS so that parameter levels will
11439 match in decls_match. */
11444 {
11446 /* As well as each TEMPLATE_PARM_CONSTRAINTS. */
11448 tf_warning_or_error);
11449 }
11450 }
11452 /* The mangled name for the NEW_FRIEND is incorrect. The function
11453 is not a template instantiation and should not be mangled like
11454 one. Therefore, we forget the mangling here; we'll recompute it
11455 later if we need it. */
11457 {
11460 }
11463 {
11464 tree old_decl;
11465 tree ns;
11467 /* We must save some information from NEW_FRIEND before calling
11468 duplicate decls since that function will free NEW_FRIEND if
11469 possible. */
11473 (new_friend_template_info
11480 {
11481 /* This declaration is a `primary' template. */
11486 }
11488 /* Inside pushdecl_namespace_level, we will push into the
11489 current namespace. However, the friend function should go
11490 into the namespace of the template. */
11500 {
11501 /* This new friend declaration matched an existing
11502 declaration. For example, given:
11504 template <class T> void f(T);
11505 template <class U> class C {
11506 template <class T> friend void f(T) {}
11507 };
11509 the friend declaration actually provides the definition
11510 of `f', once C has been instantiated for some type. So,
11511 old_decl will be the out-of-class template declaration,
11512 while new_friend is the in-class definition.
11514 But, if `f' was called before this point, the
11515 instantiation of `f' will have DECL_TI_ARGS corresponding
11516 to `T' but not to `U', references to which might appear
11517 in the definition of `f'. Previously, the most general
11518 template for an instantiation of `f' was the out-of-class
11519 version; now it is the in-class version. Therefore, we
11520 run through all specialization of `f', adding to their
11521 DECL_TI_ARGS appropriately. In particular, they need a
11522 new set of outer arguments, corresponding to the
11523 arguments for this class instantiation.
11525 The same situation can arise with something like this:
11527 friend void f(int);
11528 template <class T> class C {
11529 friend void f(T) {}
11530 };
11532 when `C<int>' is instantiated. Now, `f(int)' is defined
11533 in the class. */
11536 /* On the other hand, if the in-class declaration does
11537 *not* provide a definition, then we don't want to alter
11538 existing definitions. We can just leave everything
11539 alone. */
11540 ;
11541 else
11542 {
11546 /* Overwrite whatever template info was there before, if
11547 any, with the new template information pertaining to
11548 the declaration. */
11552 {
11553 /* We should have called reregister_specialization in
11554 duplicate_decls. */
11559 /* Instantiate it if the global has already been used. */
11563 }
11564 else
11565 {
11566 tree t;
11568 /* Indicate that the old function template is a partial
11569 instantiation. */
11577 /* Reassign any specializations already in the hash table
11578 to the new more general template, and add the
11579 additional template args. */
11583 {
11585 spec_entry elt;
11597 register_specialization
11600 }
11602 }
11603 }
11605 /* The information from NEW_FRIEND has been merged into OLD_DECL
11606 by duplicate_decls. */
11608 }
11610 /* We've just introduced a namespace-scope function in the purview
11611 without necessarily having opened the enclosing namespace, so
11612 make sure the namespace is in the purview now too. */
11617 }
11618 else
11619 {
11623 /* In the code
11624 template <class T> class C {
11625 template <class U> friend void C1<U>::f (); // case 1
11626 friend void C2<T>::f (); // case 2
11627 };
11628 we only need to make sure CONTEXT is a complete type for
11629 case 2. To distinguish between the two cases, we note that
11630 CONTEXT of case 1 remains dependent type after tsubst while
11631 this isn't true for case 2. */
11641 {
11643 /* do_friend adds the TEMPLATE_DECL for any member friend
11644 template even if it isn't a member template, i.e.
11645 template <class T> friend A<T>::f();
11646 Look through it in that case. */
11650 /* Check to see that the declaration is really present, and,
11651 possibly obtain an improved declaration. */
11656 }
11657 }
11660 }
11662 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
11663 template arguments, as for tsubst.
11665 Returns an appropriate tsubst'd friend type or error_mark_node on
11666 failure. */
11668 static tree
11670 {
11671 tree tmpl;
11674 {
11677 }
11682 else
11683 {
11686 }
11692 {
11693 /* The friend template has already been declared. Just
11694 check to see that the declarations match, and install any new
11695 default parameters. We must tsubst the default parameters,
11696 of course. We only need the innermost template parameters
11697 because that is all that redeclare_class_template will look
11698 at. */
11701 {
11705 tf_warning_or_error);
11715 }
11716 }
11717 else
11718 {
11719 /* The friend template has not already been declared. In this
11720 case, the instantiation of the template class will cause the
11721 injection of this template into the namespace scope. */
11725 {
11726 /* The new TMPL is not an instantiation of anything, so we
11727 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
11728 for the new type because that is supposed to be the
11729 corresponding template decl, i.e., TMPL. */
11736 /* Substitute into and set the constraints on the new declaration. */
11738 {
11746 }
11748 /* Inject this template into the enclosing namspace scope. */
11750 }
11751 }
11755 else
11759 }
11761 /* Returns zero if TYPE cannot be completed later due to circularity.
11762 Otherwise returns one. */
11764 static int
11766 {
11776 else
11778 }
11783 /* Instantiate the contract statement. */
11785 static tree
11787 tree in_decl)
11788 {
11794 /* Rebuild the result variable. */
11796 {
11804 /* Make sure the postcondition is valid. */
11810 /* Make the variable available for lookup. */
11812 }
11814 /* Instantiate the condition. If the return type is undeduced, process
11815 the expression as if inside a template to avoid spurious type errors. */
11825 /* And the comment. */
11830 }
11832 /* Update T by instantiating its contract attribute. */
11834 static void
11837 {
11838 /* For non-specializations, adjust the current declaration to the most general
11839 version of in_decl. Because we defer the instantiation of contracts as long
11840 as possible, they are still written in terms of the parameters (and return
11841 type) of the most general template. */
11848 /* Get the contract to be instantiated. */
11851 /* Use the complete set of template arguments for instantiation. The
11852 contract may not have been instantiated and still refer to outer levels
11853 of template parameters. */
11856 /* For member functions, make this available for semantic analysis. */
11860 {
11864 }
11871 /* Rebuild the attribute. */
11873 }
11875 /* Rebuild the attribute list for DECL, substituting into contracts
11876 as needed. */
11878 void
11880 {
11883 {
11886 }
11888 }
11890 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
11891 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
11893 static tree
11896 {
11899 /* Note that contract attributes are never substituted from this function.
11900 Their instantiation is triggered by regenerate_from_template_decl when
11901 we instantiate the body of the function. */
11909 {
11916 clauses
11920 else
11922 }
11926 {
11934 {
11939 {
11942 /* FIXME: The body of this loop should really be dispatching
11943 according to omp_ts_map[OMP_TS_CODE (TS)].tp_type instead
11944 of having hard-wired knowledge of specific selectors. */
11947 {
11955 }
11956 else
11957 {
11960 {
11965 {
11966 location_t loc
11968 match_loc);
11972 }
11974 {
11975 location_t loc
11977 match_loc);
11981 }
11983 }
11989 {
11990 bool allow_string
12000 {
12001 location_t loc
12003 match_loc);
12006 "integer expression or string "
12008 else
12012 }
12014 }
12015 }
12018 }
12020 }
12022 }
12023 /* If the first attribute argument is an identifier, don't
12024 pass it through tsubst. Attributes like mode, format,
12025 cleanup and several target specific attributes expect it
12026 unmodified. */
12028 {
12029 tree chain
12033 }
12035 {
12036 /* An attribute pack expansion. */
12045 {
12049 }
12051 }
12052 else
12060 }
12062 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
12063 unchanged or a new TREE_LIST chain. */
12065 static tree
12068 {
12073 {
12077 }
12081 {
12084 {
12087 {
12093 }
12094 }
12096 }
12099 }
12101 /* Apply any attributes which had to be deferred until instantiation
12102 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
12103 ARGS, COMPLAIN, IN_DECL are as tsubst. Returns true normally,
12104 false on error. */
12106 static bool
12109 {
12110 tree t;
12117 {
12121 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
12122 to our attributes parameter. */
12124 }
12125 else
12126 {
12128 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
12129 lookup_template_class_1, and should be preserved. */
12133 }
12135 /* save_template_attributes puts the dependent attributes at the beginning of
12136 the list; find the non-dependent ones. */
12142 /* Apply any non-dependent attributes. */
12148 /* And then any dependent ones. */
12152 {
12157 {
12160 }
12163 }
12165 /* cplus_decl_attributes can add some attributes implicitly. For templates,
12166 those attributes should have been added already when those templates were
12167 parsed, and shouldn't be added based on from which context they are
12168 first time instantiated. */
12171 optimization_default_node);
12174 NULL);
12180 }
12182 /* The template TMPL is being instantiated with the template arguments TARGS.
12183 Perform the access checks that we deferred when parsing the template. */
12185 static void
12187 {
12197 {
12205 /* Make access check error messages point to the location
12206 of the use of the typedef. */
12210 }
12211 }
12213 tree
12215 {
12219 tree typedecl;
12220 tree pbinfo;
12221 tree base_list;
12223 tree fn_context;
12232 /* Figure out which template is being instantiated. */
12236 /* Mark the type as in the process of being defined. */
12239 /* We may be in the middle of deferred access check. Disable
12240 it now. */
12243 /* Determine what specialization of the original template to
12244 instantiate. */
12249 {
12250 /* This TYPE is actually an instantiation of a partial
12251 specialization. We replace the innermost set of ARGS with
12252 the arguments appropriate for substitution. For example,
12253 given:
12255 template <class T> struct S {};
12256 template <class T> struct S<T*> {};
12258 and supposing that we are instantiating S<int*>, ARGS will
12259 presently be {int*} -- but we need {int}. */
12262 }
12263 else
12264 {
12267 }
12269 /* If the template we're instantiating is incomplete, then clearly
12270 there's nothing we can do. */
12272 {
12273 /* We can try again later. */
12276 }
12278 /* If we've recursively instantiated too many templates, stop. */
12286 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
12291 else
12292 {
12295 }
12299 /* Use #pragma pack from the template context. */
12305 /* Set the input location to the most specialized template definition.
12306 This is needed if tsubsting causes an error. */
12320 {
12323 /* Adjust visibility for template arguments. */
12325 }
12331 /* We should never instantiate a nested class before its enclosing
12332 class; we need to look up the nested class by name before we can
12333 instantiate it, and that lookup should instantiate the enclosing
12334 class. */
12339 /* Defer access checking while we substitute into the types named in
12340 the base-clause. */
12343 {
12344 tree pbase_binfo;
12347 /* Substitute into each of the bases to determine the actual
12348 basetypes. */
12350 {
12351 tree base;
12357 {
12358 expanded_bases =
12365 }
12368 {
12370 /* Extract the already-expanded base class. */
12372 else
12373 /* Substitute to figure out the base class. */
12375 NULL_TREE);
12383 }
12384 }
12386 /* The list is now in reverse order; correct that. */
12388 }
12389 /* Now call xref_basetypes to set up all the base-class
12390 information. */
12398 /* Now that our base classes are set up, enter the scope of the
12399 class, so that name lookups into base classes, etc. will work
12400 correctly. This is precisely analogous to what we do in
12401 begin_class_definition when defining an ordinary non-template
12402 class, except we also need to push the enclosing classes. */
12405 /* Now check accessibility of the types named in its base-clause,
12406 relative to the scope of the class. */
12409 /* A vector to hold members marked with attribute used. */
12412 /* Now members are processed in the order of declaration. */
12415 {
12419 {
12421 {
12423 /* A closure type for a lambda in an NSDMI or default argument.
12424 Ignore it; it will be regenerated when needed. */
12427 /* If the member is a class template, we've
12428 already substituted its type. */
12438 {
12441 /* Now, install the tag. We don't use pushtag
12442 because that does too much work -- creating an
12443 implicit typedef, which we've already done. */
12448 }
12449 }
12451 {
12452 tree r;
12462 /* Instantiate members marked with attribute used. */
12468 }
12471 /* A closure type for a lambda in an NSDMI or default argument.
12473 else
12474 {
12475 /* Build new TYPE_FIELDS. */
12479 {
12480 tree r;
12485 /* The file and line for this declaration, to
12486 assist in error message reporting. Since we
12487 called push_tinst_level above, we don't need to
12488 restore these. */
12498 {
12499 /* A capture pack became multiple fields. */
12502 }
12505 {
12509 {
12510 /* In [temp.inst]:
12512 [t]he initialization (and any associated
12513 side-effects) of a static data member does
12514 not occur unless the static data member is
12515 itself used in a way that requires the
12516 definition of the static data member to
12517 exist.
12519 Therefore, we do not substitute into the
12520 initialized for the static data member here. */
12521 finish_static_data_member_decl
12527 /* Instantiate members marked with attribute used. */
12530 }
12532 {
12533 /* Determine whether R has a valid type and can be
12534 completed later. If R is invalid, then its type
12535 is replaced by error_mark_node. */
12541 {
12542 /* If R's type couldn't be completed and
12543 it isn't a flexible array member (whose
12544 type is incomplete by definition) give
12545 an error. */
12548 }
12553 {
12556 }
12560 }
12562 /* If it is a TYPE_DECL for a class-scoped
12563 ENUMERAL_TYPE, such a thing will already have
12564 been added to the field list by tsubst_enum
12565 in finish_member_declaration case above. */
12569 {
12572 }
12573 }
12574 }
12575 }
12576 }
12577 else
12578 {
12581 {
12582 /* Build new CLASSTYPE_FRIEND_CLASSES. */
12586 {
12587 /* template <class T> friend class C; */
12589 }
12591 {
12592 /* template <class T> friend class C::D; */
12597 }
12600 {
12601 /* This could be either
12603 friend class T::C;
12605 when dependent_type_p is false or
12607 template <class U> friend class T::C;
12609 otherwise. */
12610 /* Bump processing_template_decl in case this is something like
12611 template <class T> friend struct A<T>::B. */
12616 }
12618 /* friend class C<T>; */
12622 /* Otherwise it's
12624 friend class C;
12626 where C is already declared or
12628 friend class C<int>;
12630 We don't have to do anything in these cases. */
12634 }
12635 else
12636 {
12637 /* Build new DECL_FRIENDLIST. */
12638 tree r;
12640 /* The file and line for this declaration, to
12641 assist in error message reporting. Since we
12642 called push_tinst_level above, we don't need to
12643 restore these. */
12647 {
12650 }
12655 {
12658 }
12659 }
12660 }
12661 }
12664 {
12665 /* Restore these before substituting into the lambda capture
12666 initializers. */
12669 }
12671 /* Set the file and line number information to whatever is given for
12672 the class itself. This puts error messages involving generated
12673 implicit functions at a predictable point, and the same point
12674 that would be used for non-template classes. */
12681 /* Remember if instantiating this class ran into errors, so we can avoid
12682 instantiating member functions in limit_bad_template_recursion. We set
12683 this flag even if the problem was in another instantiation triggered by
12684 this one, as that will likely also cause trouble for member functions. */
12688 /* We don't instantiate default arguments for member functions. 14.7.1:
12690 The implicit instantiation of a class template specialization causes
12691 the implicit instantiation of the declarations, but not of the
12692 definitions or default arguments, of the class member functions,
12693 member classes, static data members and member templates.... */
12698 /* Now that we've gone through all the members, instantiate those
12699 marked with attribute used. We must do this in the context of
12700 the class -- not the context we pushed from, as that might be
12701 inside a template and change the behaviour of mark_used. */
12711 /* The vtable for a template class can be emitted in any translation
12712 unit in which the class is instantiated. When there is no key
12713 method, however, finish_struct_1 will already have added TYPE to
12714 the keyed_classes. */
12719 }
12721 tree
12723 {
12724 tree r;
12730 else
12731 {
12737 }
12740 }
12742 /* Given a function parameter pack TMPL_PARM and some function parameters
12743 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
12744 and set *SPEC_P to point at the next point in the list. */
12746 tree
12748 {
12749 /* Collect all of the extra "packed" parameters into an
12750 argument pack. */
12751 tree argpack;
12762 {
12763 /* The instantiation is still a parameter pack; don't wrap it in a
12764 NONTYPE_ARGUMENT_PACK. */
12767 }
12768 else
12769 {
12770 /* Fill in PARMVEC with all of the parameters. */
12774 {
12780 }
12782 /* Build the argument packs. */
12784 }
12788 }
12790 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
12791 NONTYPE_ARGUMENT_PACK. */
12793 static tree
12795 {
12797 }
12799 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
12800 pack expansion with no extra args, 2 if it has extra args, or 0
12801 if it is not a pack expansion. */
12803 static int
12805 {
12807 /* We're being called before this happens in tsubst_pack_expansion. */
12814 /* A decl pack is itself an expansion. */
12821 }
12824 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
12826 static tree
12828 {
12835 }
12837 /* This is a subroutine of tsubst_pack_expansion.
12839 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
12840 mechanism to store the (non complete list of) arguments of the
12841 substitution and return a non substituted pack expansion, in order
12842 to wait for when we have enough arguments to really perform the
12843 substitution. */
12845 static bool
12847 tree parm_packs,
12850 {
12855 /* If one pack has an expansion and another pack has a normal
12856 argument or if one pack has an empty argument and an another
12857 one hasn't then tsubst_pack_expansion cannot perform the
12858 substitution and need to fall back on the
12859 PACK_EXPANSION_EXTRA mechanism. */
12863 {
12864 /* If all the actual packs are pack expansions, we can still
12865 subsitute directly. */
12867 {
12877 }
12879 }
12882 {
12886 parm_pack;
12888 {
12893 /* We can't substitute a pack expansion with extra args into
12894 our pattern. */
12898 else
12900 }
12903 {
12906 }
12907 }
12909 }
12911 /* [temp.variadic]/6 says that:
12913 The instantiation of a pack expansion [...]
12914 produces a list E1,E2, ..., En, where N is the number of elements
12915 in the pack expansion parameters.
12917 This subroutine of tsubst_pack_expansion produces one of these Ei.
12919 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
12920 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
12921 PATTERN, and each TREE_VALUE is its corresponding argument pack.
12922 INDEX is the index 'i' of the element Ei to produce. ARGS,
12923 COMPLAIN, and IN_DECL are the same parameters as for the
12924 tsubst_pack_expansion function.
12926 The function returns the resulting Ei upon successful completion,
12927 or error_mark_node.
12929 Note that this function possibly modifies the ARGS parameter, so
12930 it's the responsibility of the caller to restore it. */
12932 static tree
12934 tree parm_packs,
12936 tree args /* This parm gets
12938 tsubst_flags_t complain,
12939 tree in_decl)
12940 {
12941 tree t;
12944 /* For each parameter pack, change the substitution of the parameter
12945 pack to the ith argument in its argument pack, then expand the
12946 pattern. */
12948 {
12953 ith_elem_is_expansion |=
12956 /* Select the Ith argument from the pack. */
12960 {
12962 {
12967 }
12968 else
12970 }
12971 else
12972 {
12977 {
12979 /* Update the corresponding argument. */
12981 }
12982 else
12983 /* Re-use the ARGUMENT_PACK_SELECT. */
12985 }
12987 }
12989 /* Substitute into the PATTERN with the (possibly altered)
12990 arguments. */
12992 /* Expanding a fixed parameter pack from
12993 coerce_template_parameter_pack. */
12999 else
13000 {
13003 /* When expanding the fake auto... pack expansion from add_capture, we
13004 need to mark that the expansion is no longer a pack. */
13006 }
13008 /* If the Ith argument pack element is a pack expansion, then
13009 the Ith element resulting from the substituting is going to
13010 be a pack expansion as well. */
13015 }
13017 /* When the unexpanded parameter pack in a fold expression expands to an empty
13018 sequence, the value of the expression is as follows; the program is
13019 ill-formed if the operator is not listed in this table.
13021 && true
13022 || false
13023 , void() */
13025 tree
13027 {
13031 {
13040 }
13046 }
13048 /* Given a fold-expression T and a current LEFT and RIGHT operand,
13049 form an expression that combines the two terms using the
13050 operator of T. */
13052 static tree
13054 {
13059 // Handle compound assignment operators.
13066 {
13075 complain);
13076 }
13077 }
13079 /* Substitute ARGS into the pack of a fold expression T. */
13083 {
13085 }
13087 /* Substitute ARGS into the pack of a fold expression T. */
13091 {
13093 }
13095 /* Expand a PACK of arguments into a grouped as left fold.
13096 Given a pack containing elements A0, A1, ..., An and an
13097 operator @, this builds the expression:
13099 ((A0 @ A1) @ A2) ... @ An
13101 Note that PACK must not be empty.
13103 The operator is defined by the original fold expression T. */
13105 static tree
13107 {
13110 {
13113 }
13115 }
13117 /* Substitute into a unary left fold expression. */
13119 static tree
13121 tree in_decl)
13122 {
13127 {
13131 }
13134 else
13136 }
13138 /* Substitute into a binary left fold expression.
13140 Do ths by building a single (non-empty) vector of argumnts and
13141 building the expression from those elements. */
13143 static tree
13145 tree in_decl)
13146 {
13155 {
13160 }
13168 }
13170 /* Expand a PACK of arguments into a grouped as right fold.
13171 Given a pack containing elementns A0, A1, ..., and an
13172 operator @, this builds the expression:
13174 A0@ ... (An-2 @ (An-1 @ An))
13176 Note that PACK must not be empty.
13178 The operator is defined by the original fold expression T. */
13180 tree
13182 {
13183 // Build the expression.
13187 {
13190 }
13192 }
13194 /* Substitute into a unary right fold expression. */
13196 static tree
13198 tree in_decl)
13199 {
13204 {
13208 }
13211 else
13213 }
13215 /* Substitute into a binary right fold expression.
13217 Do ths by building a single (non-empty) vector of arguments and
13218 building the expression from those elements. */
13220 static tree
13222 tree in_decl)
13223 {
13232 {
13237 }
13246 }
13248 /* Walk through the pattern of a pack expansion, adding everything in
13249 local_specializations to a list. */
13251 class el_data
13252 {
13254 /* Set of variables declared within the pattern. */
13256 /* Set of AST nodes that have been visited by the traversal. */
13258 /* List of local_specializations used within the pattern. */
13259 tree extra;
13260 tsubst_flags_t complain;
13261 /* True iff we don't want to walk into unevaluated contexts. */
13263 /* The unevaluated contexts that we avoided walking. */
13268 };
13269 static tree
13271 {
13278 {
13282 }
13285 /* Remember local typedefs (85214). */
13289 {
13295 {
13298 decl2
13304 {
13307 }
13308 }
13309 }
13311 {
13312 /* Since we defer implicit capture, look in the parms and body. */
13318 }
13320 {
13322 /* Don't mess with variables declared within the pattern. */
13325 {
13326 /* Maybe pull out the PARM_DECL for a partial instantiation. */
13329 {
13335 }
13337 {
13338 /* Handle lambda capture here, since we aren't doing any
13339 substitution now, and so tsubst_copy won't call
13340 process_outer_var_ref. */
13344 {
13350 {
13351 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
13352 proxies. */
13354 {
13359 }
13361 }
13362 }
13363 }
13364 }
13368 }
13370 }
13371 static tree
13373 {
13375 /* Walk the pattern twice, ignoring unevaluated operands the first time
13376 around, so that if a local specialization appears in both an evaluated
13377 and unevaluated context we prefer to process it in the evaluated context
13378 (since e.g. process_outer_var_ref is a no-op inside an unevaluated
13379 context). */
13382 /* Now walk the unevaluated contexts we skipped the first time around. */
13385 {
13388 }
13390 }
13392 /* Extract any uses of local_specializations from PATTERN and add them to ARGS
13393 for use in PACK_EXPANSION_EXTRA_ARGS. */
13395 tree
13397 {
13398 /* Make a copy of the extra arguments so that they won't get changed
13399 out from under us. */
13405 }
13407 /* Apply any local specializations from PACK_EXPANSION_EXTRA_ARGS and add the
13408 normal template args to ARGS. */
13410 tree
13412 {
13414 {
13416 {
13417 /* The partial instantiation involved local declarations collected in
13418 extract_local_specs; map from the general template to our local
13419 context. */
13425 /* else inst is already a full instantiation of the pack. */
13427 }
13430 }
13432 {
13433 /* This can happen after dependent substitution into a
13434 requires-expr or a lambda that uses constexpr if. */
13437 }
13438 else
13441 }
13443 /* Substitute ARGS into T, which is an pack expansion
13444 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
13445 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
13446 (if only a partial substitution could be performed) or
13447 ERROR_MARK_NODE if there was an error. */
13448 tree
13450 tree in_decl)
13451 {
13452 tree pattern;
13456 tree result;
13463 /* Add in any args remembered from an earlier partial instantiation. */
13468 /* Determine the argument packs that will instantiate the parameter
13469 packs used in the expansion expression. While we're at it,
13470 compute the number of arguments to be expanded and make sure it
13471 is consistent. */
13474 {
13481 {
13486 else
13488 }
13490 {
13492 {
13495 parm_pack);
13497 }
13500 }
13502 {
13503 /* We know we have correct local_specializations if this
13504 expansion is at function scope, or if we're dealing with a
13505 local parameter in a requires expression; for the latter,
13506 tsubst_requires_expr set it up appropriately. */
13509 else
13510 /* We can't rely on local_specializations for a parameter
13511 name used later in a function declaration (such as in a
13512 late-specified return type). Even if it exists, it might
13513 have the wrong value for a recursive call. */
13517 {
13518 /* This parameter pack was used in an unevaluated context. Just
13519 make a dummy decl, since it's only used for its type. */
13524 /* Partial instantiation of the parm_pack, we can't build
13525 up an argument pack yet. */
13527 else
13529 }
13531 /* This argument pack isn't fully instantiated yet. */
13533 }
13535 {
13539 }
13540 else
13541 {
13550 }
13557 /* This can only happen if we forget to expand an argument
13558 pack somewhere else. Just return an error, silently. */
13559 {
13563 }
13566 {
13570 /* Don't bother trying to do a partial substitution with
13571 incomplete packs; we'll try again after deduction. */
13578 {
13583 pattern);
13584 else
13586 pattern);
13588 }
13590 /* Keep track of the parameter packs and their corresponding
13591 argument packs. */
13594 }
13595 else
13596 {
13597 /* We can't substitute for this parameter pack. We use a flag as
13598 well as the missing_level counter because function parameter
13599 packs don't have a level. */
13602 }
13603 }
13605 /* If the expansion is just T..., return the matching argument pack, unless
13606 we need to call convert_from_reference on all the elements. This is an
13607 important optimization; see c++/68422. */
13610 {
13613 /* If the argument pack is a single pack expansion, pull it out. */
13616 {
13620 /* Except if this isn't a simple sizeof...(T) which gets sZ
13622 else
13624 }
13626 /* Types need no adjustment, nor does sizeof..., and if we still have
13627 some pack expansion args we won't do anything yet. */
13632 /* Also optimize expression pack expansions if we can tell that the
13633 elements won't have reference type. */
13639 /* Otherwise use the normal path so we get convert_from_reference. */
13640 }
13642 /* We cannot expand this expansion expression, because we don't have
13643 all of the argument packs we need. */
13645 {
13646 /* We got some full packs, but we can't substitute them in until we
13647 have values for all the packs. So remember these until then. */
13653 }
13655 /* If NEED_LOCAL_SPECIALIZATIONS then we're in a late-specified return
13656 type, so create our own local specializations map; the current map is
13657 either NULL or (in the case of recursive unification) might have
13658 bindings that we don't want to use or alter. */
13663 {
13664 /* There were no real arguments, we're just replacing a parameter
13665 pack with another version of itself. Substitute into the
13666 pattern and return a PACK_EXPANSION_*. The caller will need to
13667 deal with that. */
13670 else
13676 {
13677 /* This is a fake auto... pack expansion created in add_capture with
13678 _PACKS that don't appear in the pattern. Copy one over. */
13685 }
13687 }
13691 /* For each argument in each argument pack, substitute into the
13692 pattern. */
13696 {
13698 i,
13700 in_decl);
13703 {
13706 }
13707 }
13709 /* Update ARGS to restore the substitution from parameter packs to
13710 their argument packs. */
13712 {
13719 else
13720 {
13728 /* Update the corresponding argument. */
13732 else
13734 }
13735 }
13737 /* If the dependent pack arguments were such that we end up with only a
13738 single pack expansion again, there's no need to keep it in a TREE_VEC. */
13744 }
13746 /* Make an argument pack out of the TREE_VEC VEC. */
13748 static tree
13750 {
13751 tree pack;
13755 else
13756 {
13759 }
13762 }
13764 /* Return an exact copy of template args T that can be modified
13765 independently. */
13767 static tree
13769 {
13777 {
13782 }
13788 }
13790 /* Substitute ARGS into the *_ARGUMENT_PACK orig_arg. */
13792 tree
13794 tree in_decl)
13795 {
13796 /* This flag is used only during deduction, and we don't expect to
13797 substitute such ARGUMENT_PACKs. */
13800 /* Substitute into each of the arguments. */
13809 /* If we're substituting into a generic ARGUMENT_PACK for a variadic
13810 template parameter, we might be able to avoid allocating a new
13811 ARGUMENT_PACK and reuse the corresponding ARGUMENT_PACK from ARGS
13812 if the substituted result is identical to it. */
13814 {
13821 {
13824 }
13825 }
13827 tree new_arg;
13829 {
13832 }
13833 else
13834 {
13837 }
13840 }
13842 /* Substitute ARGS into the vector or list of template arguments T. */
13844 tree
13846 {
13850 /* In "sizeof(X<I>)" we need to evaluate "I". */
13851 cp_evaluated ev;
13857 /* True iff the substituted result is identical to T. */
13861 {
13863 tree new_arg;
13870 {
13871 /* Substitute into an expansion expression. */
13875 /* Add to the expanded length adjustment the number of
13876 expanded arguments. We subtract one from this
13877 measurement, because the argument pack expression
13878 itself is already counted as 1 in
13879 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
13880 the argument pack is empty. */
13882 }
13885 else
13894 }
13901 /* If ARGS and T are both multi-level, the substituted result may be
13902 identical to ARGS. */
13907 /* If T appears to be a vector of generic template arguments, the
13908 substituted result may be identical to the corresponding level
13909 from ARGS. */
13911 {
13916 }
13918 /* If the substituted result is identical to MAYBE_REUSE, return
13919 it and avoid allocating a new TREE_VEC, as an optimization. */
13925 /* If T consists of only a pack expansion for which substitution yielded
13926 a TREE_VEC of the expanded elements, then reuse that TREE_VEC instead
13927 of effectively making a copy. */
13933 /* Make space for the expanded arguments coming from template
13934 argument packs. */
13936 /* T can contain TREE_VECs. That happens if T contains the
13937 arguments for a member template.
13938 In that case each TREE_VEC in T represents a level of template
13939 arguments, and T won't carry any non defaulted argument count.
13940 It will rather be the nested TREE_VECs that will carry one.
13941 In other words, T carries a non defaulted argument count only
13942 if it doesn't contain any nested TREE_VEC. */
13944 {
13948 }
13952 {
13957 {
13958 /* Now expand the template argument pack "in place". */
13961 }
13962 else
13963 {
13965 out++;
13966 }
13967 }
13971 }
13973 /* Substitute ARGS into one level PARMS of template parameters. */
13975 static tree
13977 {
13984 {
13992 }
13995 }
13997 /* Return the result of substituting ARGS into the template parameters
13998 given by PARMS. If there are m levels of ARGS and m + n levels of
13999 PARMS, then the result will contain n levels of PARMS. For
14000 example, if PARMS is `template <class T> template <class U>
14001 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
14002 result will be `template <int*, double, class V>'. */
14004 static tree
14006 {
14010 /* When substituting into a template, we must set
14011 PROCESSING_TEMPLATE_DECL as the template parameters may be
14012 dependent if they are based on one-another, and the dependency
14013 predicates are short-circuit outside of templates. */
14020 {
14029 }
14034 }
14036 /* Return the result of substituting ARGS into one template parameter
14037 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
14038 parameter and which TREE_PURPOSE is the default argument of the
14039 template parameter. */
14041 static tree
14043 {
14066 }
14068 /* Substitute in-place the TEMPLATE_PARM_CONSTRAINTS of each template
14069 parameter in PARMS for sake of declaration matching. */
14071 static void
14073 tsubst_flags_t complain)
14074 {
14077 {
14083 }
14085 }
14087 /* Substitute the ARGS into the indicated aggregate (or enumeration)
14088 type T. If T is not an aggregate or enumeration type, it is
14089 handled as if by tsubst. IN_DECL is as for tsubst. If
14090 ENTERING_SCOPE is nonzero, T is the context for a template which
14091 we are presently tsubst'ing. Return the substituted value. */
14093 static tree
14095 tree args,
14096 tsubst_flags_t complain,
14097 tree in_decl,
14099 {
14103 /* Handle typedefs via tsubst so that they get consistently reused. */
14105 {
14110 /* The effect of entering_scope is that for a dependent specialization
14111 A<T>, lookup_template_class prefers to return A's primary template
14112 type instead of the implicit instantiation. So when entering_scope,
14113 we mirror this behavior by inspecting TYPE_CANONICAL appropriately,
14114 taking advantage of the fact that lookup_template_class links the two
14115 types by setting TYPE_CANONICAL of the latter to the former. */
14124 }
14127 {
14135 }
14136 }
14138 /* The part of tsubst_aggr_type that's shared with the RECORD_, UNION_
14139 and ENUMERAL_TYPE cases of tsubst. */
14141 static tree
14143 tree args,
14144 tsubst_flags_t complain,
14145 tree in_decl,
14147 {
14149 {
14152 /* Figure out what arguments are appropriate for the
14153 type we are trying to find. For example, given:
14155 template <class T> struct S;
14156 template <class T, class U> void f(T, U) { S<U> su; }
14158 and supposing that we are instantiating f<int, double>,
14159 then our ARGS will be {int, double}, but, when looking up
14160 S we only want {double}. */
14169 }
14170 else
14171 /* This is not a template type, so there's nothing to do. */
14173 }
14175 /* Map from a FUNCTION_DECL to a vec of default argument instantiations,
14176 indexed in reverse order of the parameters. */
14180 /* Return a reference to the vec* of defarg insts for FN. */
14184 {
14188 tree_vec_map **slot
14191 {
14194 }
14196 }
14198 /* Substitute into the default argument ARG (a default argument for
14199 FN), which has the indicated TYPE. */
14201 tree
14203 tsubst_flags_t complain)
14204 {
14207 /* This can happen in invalid code. */
14211 /* Shortcut {}. */
14226 /* Remember the location of the pointer to the vec rather than the location
14227 of the particular element, in case the vec grows in tsubst_expr. */
14229 /* Index in reverse order to avoid allocating space for initial parameters
14230 that don't have default arguments. */
14237 /* This default argument came from a template. Instantiate the
14238 default argument here, not in tsubst. In the case of
14239 something like:
14241 template <class T>
14242 struct S {
14243 static T t();
14244 void f(T = t());
14245 };
14247 we must be careful to do name lookup in the scope of S<T>,
14248 rather than in the current class. */
14252 /* So in_immediate_context knows this is a default argument. */
14256 /* The default argument expression may cause implicitly defined
14257 member functions to be synthesized, which will result in garbage
14258 collection. We must treat this situation as if we were within
14259 the body of function so as to avoid collecting live data on the
14260 stack. */
14267 /* Make sure the default argument is reasonable. */
14284 }
14286 /* Substitute into all the default arguments for FN. */
14288 static void
14290 {
14291 tree arg;
14292 tree tmpl_args;
14296 /* If this function is not yet instantiated, we certainly don't need
14297 its default arguments. */
14300 /* Don't do this again for clones. */
14306 arg;
14312 complain);
14313 }
14315 /* Hash table mapping a FUNCTION_DECL to its dependent explicit-specifier. */
14318 /* Store a pair to EXPLICIT_SPECIFIER_MAP. */
14320 void
14322 {
14327 }
14329 /* Lookup an element in EXPLICIT_SPECIFIER_MAP. */
14331 tree
14333 {
14335 }
14337 /* Given T, a FUNCTION_TYPE or METHOD_TYPE, construct and return a corresponding
14338 FUNCTION_TYPE or METHOD_TYPE whose return type is RETURN_TYPE, argument types
14339 are ARG_TYPES, and exception specification is RAISES, and otherwise is
14340 identical to T. */
14342 static tree
14345 {
14348 tree new_type;
14350 {
14353 }
14354 else
14355 {
14357 /* Don't pick up extra function qualifiers from the basetype. */
14360 {
14361 /* [temp.deduct]
14363 Type deduction may fail for any of the following
14364 reasons:
14366 -- Attempting to create "pointer to member of T" when T
14367 is not a class type. */
14370 r);
14372 }
14376 }
14382 }
14384 /* Check if the function type of DECL, a FUNCTION_DECL, agrees with the type of
14385 each of its formal parameters. If there is a disagreement then rebuild
14386 DECL's function type according to its formal parameter types, as part of a
14387 resolution for Core issues 1001/1322. */
14389 static void
14391 {
14394 {
14397 {
14401 {
14404 }
14408 }
14409 }
14420 {
14425 }
14427 {
14437 }
14445 }
14447 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
14449 static tree
14452 {
14457 /* Nobody should be tsubst'ing into non-template functions. */
14462 {
14465 }
14467 {
14468 /* If T is not dependent, just return it. */
14473 /* A non-templated friend doesn't get DECL_TEMPLATE_INFO. */
14477 /* Calculate the most general template of which R is a
14478 specialization. */
14481 /* We're substituting a lambda function under tsubst_lambda_expr but not
14482 directly from it; find the matching function we're already inside.
14483 But don't do this if T is a generic lambda with a single level of
14484 template parms, as in that case we're doing a normal instantiation. */
14490 /* Calculate the complete set of arguments used to
14491 specialize R. */
14493 {
14495 (DECL_TEMPLATE_RESULT
14501 /* Check to see if we already have this specialization. */
14504 /* The spec for these args might be a partial instantiation of the
14505 template, but here what we want is the FUNCTION_DECL. */
14507 }
14508 else
14510 }
14511 else
14512 {
14513 /* This special case arises when we have something like this:
14515 template <class T> struct S {
14516 friend void f<int>(int, double);
14517 };
14519 Here, the DECL_TI_TEMPLATE for the friend declaration
14520 will be an IDENTIFIER_NODE. We are being called from
14521 tsubst_friend_function, and we want only to create a
14522 new decl (R) with appropriate types so that we can call
14523 determine_specialization. */
14524 friend_case:
14527 }
14534 /* If this is a static or xobj lambda, remove the 'this' pointer added in
14535 tsubst_lambda_expr now that we know the closure type. */
14549 /* If we hit excessive deduction depth, the type is bogus even if
14550 it isn't error_mark_node, so don't build a decl. */
14554 /* We do NOT check for matching decls pushed separately at this
14555 point, as they may not represent instantiations of this
14556 template, and in any case are considered separate under the
14557 discrete model. */
14561 /* Clear out the mangled name and RTL for the instantiation. */
14564 /* Leave DECL_INITIAL set on deleted instantiations. */
14570 /* Handle explicit(dependent-expr). */
14572 {
14580 else
14581 {
14584 }
14585 }
14587 /* OpenMP UDRs have the only argument a reference to the declared
14588 type. We want to diagnose if the declared type is a reference,
14589 which is invalid, but as references to references are usually
14590 quietly merged, diagnose it here. */
14592 {
14593 tree argtype
14598 "reference type %qT in "
14602 argtype);
14603 }
14606 /* Type-conversion operator. Reconstruct the name, in
14607 case it's the name of one of the template's parameters. */
14617 {
14622 }
14631 /* If this is an instantiation of a function with internal
14632 linkage, we already know what object file linkage will be
14633 assigned to the instantiation. */
14642 /* We'll re-clone as appropriate in instantiate_template. */
14645 /* If we aren't complaining now, return on error before we register
14646 the specialization so that we'll complain eventually. */
14652 /* If we are looking at an xobj lambda, we might need to check the type of
14653 its xobj parameter. */
14655 {
14662 /* If a lambda has an empty capture clause, an xobj parameter of
14665 /* If we are coming from tsubst_lambda_expr we might not have
14666 substituted into our xobj parameter yet. We can't error out until
14667 we know what the type really is so do nothing...
14668 ...but if we are instantiating the call op for real and we don't
14669 have a real type then something has gone incredibly wrong. */
14671 else
14672 {
14673 /* We have a lambda with captures, and know the type of the xobj
14674 parameter, time to check it. */
14677 {
14678 /* This error does not emit when the lambda's call operator
14679 template is instantiated by taking its address, such as in
14680 the following case:
14682 auto f = [x = 0](this auto&&){};
14683 int (*fp)(int&) = &decltype(f)::operator();
14685 It only emits when explicitly calling the call operator with
14686 an explicit template parameter:
14688 template<typename T>
14689 struct S : T {
14690 using T::operator();
14691 operator int() const {return {};}
14692 };
14694 auto s = S{[x = 0](this auto&&) {}};
14695 s.operator()<int>();
14697 This is due to resolve_address_of_overloaded_function being
14698 deficient at reporting candidates when overload resolution
14699 fails.
14701 This diagnostic will be active in the first case if/when
14702 resolve_address_of_overloaded_function is fixed to properly
14703 emit candidates upon failure to resolve to an overload. */
14708 }
14709 }
14710 }
14712 /* Associate the constraints directly with the instantiation. We
14713 don't substitute through the constraints; that's only done when
14714 they are checked. */
14727 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
14728 this in the special friend case mentioned above where
14729 GEN_TMPL is NULL. */
14731 {
14737 {
14738 tree new_r
14741 /* We instantiated this while substituting into
14742 the type earlier (template/friend54.C). */
14744 }
14746 /* We're not supposed to instantiate default arguments
14747 until they are called, for a template. But, for a
14748 declaration like:
14750 template <class T> void f ()
14751 { extern void g(int i = T()); }
14753 we should do the substitution when the template is
14754 instantiated. We handle the member function case in
14755 instantiate_class_template since the default arguments
14756 might refer to other members of the class. */
14761 }
14763 {
14766 }
14767 else
14770 /* Copy the list of befriending classes. */
14774 {
14778 }
14781 {
14785 /* If this is an instantiation of a member template, clone it.
14786 If it isn't, that'll be handled by
14787 clone_constructors_and_destructors. */
14790 }
14796 /* Possibly limit visibility based on template args. */
14799 {
14803 }
14817 }
14819 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
14821 static tree
14824 {
14825 /* We can get here when processing a member function template,
14826 member class template, or template template parameter. */
14829 tree spec;
14830 tree tmpl_args;
14832 tree r;
14836 {
14837 /* Template template parameter is treated here. */
14841 /* If we get a real template back, return it. This can happen in
14842 the context of most_specialized_partial_spec. */
14845 else
14846 /* The new TEMPLATE_DECL was built in
14847 reduce_template_parm_level. */
14850 }
14853 {
14854 /* We might already have an instance of this template.
14855 The ARGS are for the surrounding class type, so the
14856 full args contain the tsubst'd args for the context,
14857 plus the innermost args from the template decl. */
14861 /* Because this is a template, the arguments will still be
14862 dependent, even after substitution. If
14863 PROCESSING_TEMPLATE_DECL is not set, the dependency
14864 predicates will short-circuit. */
14872 /* If this is a default template template argument,
14873 tsubst might not have changed anything. */
14880 {
14882 /* Type partial instantiations are stored as the type by
14883 lookup_template_class_1, not here as the template. */
14888 }
14889 }
14891 /* Make a new template decl. It will be similar to the
14892 original, but will record the current template arguments.
14893 We also create a new function declaration, which is just
14894 like the old one, but points to this new template, rather
14895 than the old one. */
14900 // Build new template info linking to the original template decl.
14902 {
14905 }
14906 else
14909 /* The template parameters for this new template are all the
14910 template parameters for the old template, except the
14911 outermost level of parameters. */
14914 = current_template_parms
14915 = (lambda_tparms
14916 ? lambda_tparms
14918 complain));
14926 else
14927 {
14929 {
14932 }
14936 else
14938 }
14944 {
14945 /* For a partial specialization, we need to keep pointing to
14946 the primary template. */
14948 {
14951 }
14955 }
14957 {
14960 }
14961 else
14962 {
14964 /* Set DECL_TI_ARGS to the full set of template arguments,
14965 which tsubst_function_decl / tsubst_decl didn't do due to
14966 use_spec_table=false. */
14969 }
14976 {
14977 /* Propagate module information from the decl. */
14980 /* If this is a constrained template, the above tsubst of
14981 inner can find the unconstrained template, which may have
14982 come from an import. This is ok, because we don't
14983 register this instantiation (see below). */
14985 || (TEMPLATE_PARMS_CONSTRAINTS
14987 }
14998 {
14999 /* Record this non-type partial instantiation. */
15000 /* FIXME we'd like to always register the TEMPLATE_DECL, or always
15001 the DECL_TEMPLATE_RESULT, but it seems the modules code relies
15002 on this current behavior. */
15005 else
15007 }
15010 }
15012 /* True if FN is the op() for a lambda in an uninstantiated template. */
15014 bool
15016 {
15021 }
15023 /* True if FN is the substitution (via tsubst_lambda_expr) of a function for
15024 which the above is true. */
15026 bool
15028 {
15034 }
15036 /* Return the LAMBDA_EXPR from which T was ultimately regenerated.
15037 If T is not a regenerated LAMBDA_EXPR, return T. */
15039 tree
15041 {
15045 }
15047 /* Return the set of template arguments used to regenerate the lambda T
15048 from its most general lambda. */
15050 tree
15052 {
15058 else
15060 }
15062 /* We're instantiating a variable from template function TCTX. Return the
15063 corresponding current enclosing scope. We can match them up using
15064 DECL_SOURCE_LOCATION because lambdas only ever have one source location, and
15065 the DECL_SOURCE_LOCATION for a function instantiation is updated to match
15066 the template definition in regenerate_decl_from_template. */
15068 static tree
15070 {
15073 /* We shouldn't ever need to do this for other artificial functions. */
15080 }
15082 /* Substitute the ARGS into the T, which is a _DECL. Return the
15083 result of the substitution. Issue error and warning messages under
15084 control of COMPLAIN. The flag USE_SPEC_TABLE controls if we look up
15085 and insert into the specializations table or if we can assume it's
15086 the caller's responsibility; this is used by instantiate_template
15087 to avoid doing some redundant work. */
15089 static tree
15092 {
15093 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
15094 location_t saved_loc;
15102 /* Set the filename and linenumber to improve error-reporting. */
15107 {
15116 use_spec_table);
15120 {
15128 {
15129 /* If there is a local specialization that isn't a
15130 parameter pack, it means that we're doing a "simple"
15131 substitution from inside tsubst_pack_expansion. Just
15132 return the local specialization (which will be a single
15133 parm). */
15140 /* Expand the TYPE_PACK_EXPANSION that provides the types for
15141 the parameters in this function parameter pack. */
15145 {
15148 /* Zero-length parameter packs are boring. Just substitute
15149 into the chain. */
15153 }
15154 else
15155 {
15156 /* All we did was update the type. Make a note of that. */
15159 }
15160 }
15162 /* Loop through all of the parameters we'll build. When T is
15163 a function parameter pack, LEN is the number of expanded
15164 types in EXPANDED_TYPES; otherwise, LEN is 1. */
15167 {
15174 /* We're on the Ith parameter of the function parameter
15175 pack. */
15176 {
15177 /* Get the Ith type. */
15180 /* Rename the parameter to include the index. */
15183 }
15185 /* We're dealing with a normal parameter. */
15193 {
15196 else
15199 }
15210 /* Keep track of the first new parameter we
15211 generate. That's what will be returned to the
15212 caller. */
15216 /* Build a proper chain of parameters when substituting
15217 into a function parameter pack. */
15220 }
15222 /* If cp_unevaluated_operand is set, we're just looking for a
15223 single dummy parameter, so don't keep going. */
15228 /* FIRST_R contains the start of the chain we've built. */
15230 }
15234 {
15241 {
15242 /* This field is a lambda capture pack. Return a TREE_VEC of
15243 the expanded fields to instantiate_class_template_1. */
15247 {
15250 }
15251 else
15252 {
15253 /* All we did was update the type. Make a note of that. */
15256 }
15257 }
15260 {
15263 {
15267 }
15277 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
15278 number of bits. */
15283 {
15284 /* Set up DECL_TEMPLATE_INFO so that we can get at the
15285 NSDMI in perform_member_init. Still set DECL_INITIAL
15286 so that we know there is one. */
15291 }
15292 /* We don't have to set DECL_CONTEXT here; it is set by
15293 finish_member_declaration. */
15302 }
15306 }
15310 /* We reach here only for member using decls. We also need to check
15311 uses_template_parms because DECL_DEPENDENT_P is not set for a
15312 using-declaration that designates a member of the current
15313 instantiation (c++/53549). */
15316 {
15317 /* True iff this using-decl was written as a pack expansion
15318 (and a pack appeared in its scope or name). If a pack
15319 appeared in both, we expand the packs separately and
15320 manually merge them. */
15325 {
15328 in_decl);
15330 }
15331 else
15337 {
15341 {
15344 }
15348 }
15349 else
15357 {
15359 {
15364 }
15366 }
15374 {
15383 {
15386 }
15390 }
15394 }
15395 else
15396 {
15399 }
15404 {
15415 {
15416 /* If this is the canonical decl, we don't have to
15417 mess with instantiations, and often we can't (for
15418 typename, template type parms and such). Note that
15419 TYPE_NAME is not correct for the above test if
15420 we've copied the type for a typedef. */
15426 }
15428 /* Check to see if we already have the specialization we
15429 need. */
15435 {
15438 {
15440 complain,
15443 /* The context and type of an injected-class-name are
15444 the same, so we don't need to substitute both. */
15446 /* If CTX is unchanged, then T is in fact the
15447 specialization we want. That situation occurs when
15448 referencing a static data member within in its own
15449 class. We can use pointer equality, rather than
15450 same_type_p, because DECL_CONTEXT is always
15451 canonical... */
15453 /* ... unless T is a member template; in which
15454 case our caller can be willing to create a
15455 specialization of that template represented
15456 by T. */
15460 }
15463 {
15466 {
15473 }
15474 else
15476 }
15477 }
15478 else
15479 {
15481 /* Subsequent calls to pushdecl will fill this in. */
15483 /* A local variable. */
15485 /* Unless this is a reference to a static variable from an
15486 enclosing function, in which case we need to fill it in now. */
15488 {
15492 }
15494 }
15495 /* If we already have the specialization we need, there is
15496 nothing more to do. */
15498 {
15501 }
15503 /* Create a new node for the specialization we need. */
15505 {
15508 else
15518 /* Substituting the type might have recursively instantiated this
15519 same alias (c++/86171). */
15522 {
15525 }
15526 }
15531 {
15535 {
15536 /* It may seem that this case cannot occur, since:
15538 typedef void f();
15539 void g() { f x; }
15541 declares a function, not a variable. However:
15543 typedef void f();
15544 template <typename T> void g() { T t; }
15545 template void g<f>();
15547 is an attempt to declare a variable with function
15548 type. */
15550 /* R is not yet sufficiently initialized, so we
15551 just use its name. */
15554 }
15556 /* Wait until cp_finish_decl to set this again, to handle
15557 circular dependency (template/instantiate6.C). */
15562 {
15564 /* If the DECL_VALUE_EXPR is converted to the declared type,
15565 preserve the identity so that gimplify_type_sizes works. */
15571 {
15574 }
15583 else
15587 }
15591 }
15597 /* Clear out the mangled name and RTL for the instantiation. */
15603 /* The initializer must not be expanded until it is required;
15604 see [temp.inst]. */
15608 {
15614 /* Possibly limit visibility based on template args. */
15617 {
15621 }
15625 }
15628 {
15629 /* A static data member declaration is always marked
15630 external when it is declared in-class, even if an
15631 initializer is present. We mimic the non-template
15632 processing here. */
15641 }
15642 else
15643 {
15648 }
15657 /* Preserve a typedef that names a type. */
15659 {
15663 /* common_handle_aligned_attribute doesn't apply the alignment
15664 to DECL_ORIGINAL_TYPE. */
15668 }
15671 }
15676 }
15677 #undef RETURN
15679 out:
15680 /* Restore the file and line information. */
15684 }
15686 /* Substitute into the complete parameter type list PARMS. */
15688 tree
15690 tree args,
15691 tsubst_flags_t complain,
15692 tree in_decl)
15693 {
15695 }
15697 /* Substitute into the ARG_TYPES of a function type.
15698 If END is a TREE_CHAIN, leave it and any following types
15699 un-substituted. */
15701 static tree
15703 tree args,
15704 tree end,
15705 tsubst_flags_t complain,
15706 tree in_decl)
15707 {
15716 {
15717 /* For a pack expansion, perform substitution on the
15718 entire expression. Later on, we'll handle the arguments
15719 one-by-one. */
15724 /* So that we'll spin through the parameters, one by one. */
15726 else
15727 {
15728 /* We only partially substituted into the parameter
15729 pack. Our type is TYPE_PACK_EXPANSION. */
15732 }
15733 }
15734 else
15737 /* Check if a substituted type is erroneous before substituting into
15738 the rest of the chain. */
15740 {
15747 {
15749 {
15753 }
15755 }
15756 }
15758 /* We do not substitute into default arguments here. The standard
15759 mandates that they be instantiated only when needed, which is
15760 done in build_over_call. */
15763 /* Except that we do substitute default arguments under tsubst_lambda_expr,
15764 since the new op() won't have any associated template arguments for us
15765 to refer to later. */
15777 {
15781 /* Do array-to-pointer, function-to-pointer conversion, and ignore
15782 top-level qualifiers as required. */
15786 {
15787 /* We've instantiated a template before its default arguments
15788 have been parsed. This can happen for a nested template
15789 class, and is not an error unless we require the default
15790 argument in a call of this function. */
15791 remaining_arg_types
15794 remaining_arg_types);
15795 }
15796 else
15797 remaining_arg_types
15799 }
15802 }
15804 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
15805 *not* handle the exception-specification for FNTYPE, because the
15806 initial substitution of explicitly provided template parameters
15807 during argument deduction forbids substitution into the
15808 exception-specification:
15810 [temp.deduct]
15812 All references in the function type of the function template to the
15813 corresponding template parameters are replaced by the specified tem-
15814 plate argument values. If a substitution in a template parameter or
15815 in the function type of the function template results in an invalid
15816 type, type deduction fails. [Note: The equivalent substitution in
15817 exception specifications is done only when the function is instanti-
15818 ated, at which point a program is ill-formed if the substitution
15819 results in an invalid type.] */
15821 static tree
15823 tree args,
15824 tsubst_flags_t complain,
15825 tree in_decl)
15826 {
15827 tree return_type;
15830 /* The TYPE_CONTEXT is not used for function/method types. */
15833 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
15834 failure. */
15838 {
15839 /* Substitute the argument types. */
15851 {
15852 /* DR 1207: 'this' is in scope in the trailing return type. */
15854 }
15856 /* Substitute the return type. */
15860 {
15863 }
15864 }
15865 else
15866 /* Substitute the return type. */
15871 /* DR 486 clarifies that creation of a function type with an
15872 invalid return type is a deduction failure. */
15875 {
15877 {
15880 else
15882 }
15884 }
15887 {
15888 /* Substitute the argument types. */
15893 }
15895 /* Construct a new type node and return it. */
15898 }
15900 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
15901 ARGS into that specification, and return the substituted
15902 specification. If there is no specification, return NULL_TREE. */
15904 static tree
15906 tree args,
15907 tsubst_flags_t complain,
15908 tree in_decl,
15910 {
15911 tree specs;
15912 tree new_specs;
15917 {
15918 /* A noexcept-specifier. */
15923 {
15924 /* Defer instantiation of noexcept-specifiers to avoid
15925 excessive instantiations (c++/49107). */
15928 {
15929 /* We already partially instantiated this member template,
15930 so combine the new args with the old. */
15935 }
15936 else
15937 {
15940 }
15941 }
15942 else
15943 {
15945 {
15947 args);
15949 }
15951 }
15953 /* We've instantiated a template before a noexcept-specifier
15954 contained therein has been parsed. This can happen for
15955 a nested template class:
15957 struct S {
15958 template<typename> struct B { B() noexcept(...); };
15959 struct A : B<int> { ... use B() ... };
15960 };
15962 where completing B<int> will trigger instantiating the
15963 noexcept, even though we only parse it at the end of S. */
15965 {
15968 }
15969 }
15971 {
15974 else
15976 {
15977 tree spec;
15982 {
15983 /* Expand the pack expansion type. */
15986 in_decl);
15992 else
15993 {
15994 /* We're substituting into a member template, so
15995 we got a TYPE_PACK_EXPANSION back. Add that
15996 expansion and move on. */
16000 expanded_specs,
16001 complain);
16004 }
16005 }
16008 {
16011 else
16016 complain);
16017 }
16020 }
16021 }
16023 }
16025 /* Substitute through a TREE_LIST of types or expressions, handling pack
16026 expansions. */
16028 tree
16030 {
16037 ;
16039 {
16043 }
16046 else
16054 ;
16056 {
16060 }
16063 else
16070 ;
16075 else
16086 /* Determine the number of arguments. */
16088 {
16091 }
16094 else
16098 {
16106 else
16108 }
16111 }
16113 /* Take the tree structure T and replace template parameters used
16114 therein with the argument vector ARGS. IN_DECL is an associated
16115 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
16116 Issue error and warning messages under control of COMPLAIN. Note
16117 that we must be relatively non-tolerant of extensions here, in
16118 order to preserve conformance; if we allow substitutions that
16119 should not be allowed, we may allow argument deductions that should
16120 not succeed, and therefore report ambiguous overload situations
16121 where there are none. In theory, we could allow the substitution,
16122 but indicate that it should have failed, and allow our caller to
16123 make sure that the right thing happens, but we don't try to do this
16124 yet.
16126 This function is used for dealing with types, decls and the like;
16127 for expressions, use tsubst_expr or tsubst_copy. */
16129 tree
16131 {
16166 /* Reuse typedefs. We need to do this to handle dependent attributes,
16167 such as attribute aligned. */
16170 {
16174 {
16175 /* DECL represents an alias template and we want to
16176 instantiate it. */
16180 }
16184 {
16188 }
16193 else
16194 /* The typedef is from a non-template context. */
16198 {
16200 r = cp_build_qualified_type
16204 }
16205 else
16206 {
16207 /* We don't have an instantiation yet, so drop the typedef. */
16212 }
16213 }
16230 {
16234 /* Fall through. */
16260 {
16265 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
16266 needed. */
16272 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
16273 with TREE_SIDE_EFFECTS that indicates this is not an integral
16274 constant expression. */
16277 {
16280 }
16283 }
16287 {
16295 else
16297 }
16298 /* Fall through. */
16302 {
16316 {
16319 /* See through ARGUMENT_PACK_SELECT arguments. */
16322 }
16327 {
16329 /* If ARG is an argument pack, we don't actually want to
16330 perform a substitution here, because substitutions
16331 for argument packs are only done
16332 element-by-element. We can get to this point when
16333 substituting the type of a non-type template
16334 parameter pack, when that type actually contains
16335 template parameter packs from an outer template, e.g.,
16337 template<typename... Types> struct A {
16338 template<Types... Values> struct B { };
16339 }; */
16343 {
16346 /* When building concept checks for the purpose of
16347 deducing placeholders, we can end up with wildcards
16348 where types are expected. Adjust this to the deduced
16349 value. */
16357 return cp_build_qualified_type
16359 }
16361 {
16362 /* We are processing a type constructed from a
16363 template template parameter. */
16374 /* Consider this code:
16376 template <template <class> class Template>
16377 struct Internal {
16378 template <class Arg> using Bind = Template<Arg>;
16379 };
16381 template <template <class> class Template, class Arg>
16382 using Instantiate = Template<Arg>; //#0
16384 template <template <class> class Template,
16385 class Argument>
16386 using Bind =
16387 Instantiate<Internal<Template>::template Bind,
16388 Argument>; //#1
16390 When #1 is parsed, the
16391 BOUND_TEMPLATE_TEMPLATE_PARM representing the
16392 parameter `Template' in #0 matches the
16393 UNBOUND_CLASS_TEMPLATE representing the argument
16394 `Internal<Template>::template Bind'; We then want
16395 to assemble the type `Bind<Argument>' that can't
16396 be fully created right now, because
16397 `Internal<Template>' not being complete, the Bind
16398 template cannot be looked up in that context. So
16399 we need to "store" `Bind<Argument>' for later
16400 when the context of Bind becomes complete. Let's
16401 store that in a TYPENAME_TYPE. */
16405 argvec),
16406 typename_type,
16407 complain);
16409 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
16410 are resolving nested-types in the signature of a
16411 member function templates. Otherwise ARG is a
16412 TEMPLATE_DECL and is the real template to be
16413 instantiated. */
16421 complain);
16422 return cp_build_qualified_type
16424 }
16427 else
16428 /* TEMPLATE_PARM_INDEX. */
16430 }
16433 /* This can happen during the attempted tsubst'ing in
16434 unify. This means that we don't yet have any information
16435 about the template parameter in question. */
16438 /* Early in template argument deduction substitution, we don't
16439 want to reduce the level of 'auto', or it will be confused
16440 with a normal template parm in subsequent deduction.
16441 Similarly, don't reduce the level of template parameters to
16442 avoid mismatches when deducing their types. */
16446 /* If we get here, we must have been looking at a parm for a
16447 more deeply nested template. Make a new version of this
16448 template parameter, but with a lower level. */
16451 {
16456 {
16459 }
16465 /* Cache lowering a type parameter or a simple template
16466 template parameter. */
16470 {
16482 /* Propagate constraints on placeholders since they are
16483 only instantiated during satisfaction. */
16488 else
16490 }
16498 {
16500 /* We might need to substitute into the types of non-type
16501 template parameters. This also lowers the level of
16502 the ttp appropriately. */
16515 }
16518 /* OK, now substitute the type of the non-type parameter. We
16519 couldn't do it earlier because it might be an auto parameter,
16520 and we wouldn't need to if we had an argument. */
16529 }
16532 }
16538 /* We should never be tsubsting a binfo. */
16542 /* A vector of template arguments. */
16548 {
16552 /* [temp.deduct]
16554 Type deduction may fail for any of the following
16555 reasons:
16557 -- Attempting to create a pointer to reference type.
16558 -- Attempting to create a reference to a reference type or
16559 a reference to void.
16561 Core issue 106 says that creating a reference to a reference
16562 during instantiation is no longer a cause for failure. We
16563 only enforce this check in strict C++98 mode. */
16567 {
16570 /* We keep track of the last time we issued this error
16571 message to avoid spewing a ton of messages during a
16572 single bad template instantiation. */
16575 {
16580 else
16583 }
16586 }
16590 {
16592 {
16595 type);
16596 else
16598 type);
16599 }
16601 }
16603 {
16607 }
16609 /* In C++0x, during template argument substitution, when there is an
16610 attempt to create a reference to a reference type, reference
16611 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
16613 "If a template-argument for a template-parameter T names a type
16614 that is a reference to a type A, an attempt to create the type
16615 'lvalue reference to cv T' creates the type 'lvalue reference to
16616 A,' while an attempt to create the type type rvalue reference to
16617 cv T' creates the type T"
16618 */
16619 r = cp_build_reference_type
16622 else
16627 /* Will this ever be needed for TYPE_..._TO values? */
16631 }
16633 {
16636 {
16637 /* [temp.deduct]
16639 Type deduction may fail for any of the following
16640 reasons:
16642 -- Attempting to create "pointer to member of T" when T
16643 is not a class type. */
16647 }
16649 {
16653 }
16655 {
16659 }
16662 {
16663 /* The type of the implicit object parameter gets its
16664 cv-qualifiers from the FUNCTION_TYPE. */
16665 tree memptr;
16666 tree method_type
16671 complain);
16672 }
16673 else
16676 complain);
16677 }
16680 {
16681 tree fntype;
16682 tree specs;
16687 /* Substitute the exception specification. */
16695 }
16697 {
16702 /* As an optimization, we avoid regenerating the array type if
16703 it will obviously be the same as T. */
16707 /* These checks should match the ones in create_array_type_for_decl.
16709 [temp.deduct]
16711 The deduction may fail for any of the following reasons:
16713 -- Attempting to create an array with an element type that
16714 is void, a function type, or a reference type, or [DR337]
16715 an abstract class type. */
16721 {
16725 }
16738 {
16741 }
16744 }
16747 {
16750 {
16753 in_decl);
16758 {
16763 }
16765 }
16766 else
16779 {
16783 }
16785 {
16786 /* Normally, make_typename_type does not require that the CTX
16787 have complete type in order to allow things like:
16789 template <class T> struct S { typename S<T>::X Y; };
16791 But, such constructs have already been resolved by this
16792 point, so here CTX really should have complete type, unless
16793 it's a partial instantiation. */
16796 }
16798 /* FIXME: TYPENAME_IS_CLASS_P conflates 'class' vs 'struct' vs 'union'
16799 tags. TYPENAME_TYPE should probably remember the exact tag that
16800 was written. */
16801 enum tag_types tag_type
16811 {
16814 }
16817 {
16819 {
16823 else
16825 }
16827 {
16831 else
16833 }
16834 }
16836 return cp_build_qualified_type
16838 }
16841 {
16853 }
16856 {
16857 tree type;
16871 complain);
16872 }
16875 {
16876 tree type;
16893 else
16894 {
16898 /* In a template ~id could be either a complement expression
16899 or an unqualified-id naming a destructor; if instantiating
16900 it produces an expression, it's not an id-expression or
16901 member access. */
16904 }
16909 }
16912 {
16916 else
16923 }
16943 /* We should use one of the expression tsubsts for these codes. */
16949 }
16950 }
16952 /* Convenience wrapper over tsubst for substituting into the LHS
16953 of the :: scope resolution operator. */
16955 static tree
16957 {
16960 }
16962 /* Convenience wrapper over tsubst for substituting into an id-expression
16963 without resolving its terminal name. */
16965 static tree
16967 {
16969 }
16971 /* OLDFNS is a lookup set of member functions from some class template, and
16972 NEWFNS is a lookup set of member functions from NEWTYPE, a specialization
16973 of that class template. Return the subset of NEWFNS which are
16974 specializations of a function from OLDFNS. */
16976 static tree
16978 {
16979 /* Record all member functions from the old lookup set OLDFNS into
16980 VISIBLE_SET. */
16984 {
16986 {
16987 /* Imprecisely handle dependent using-decl by keeping all members
16988 in the new lookup set that are defined in a base class, i.e.
16989 members that could plausibly have been introduced by this
16990 dependent using-decl.
16991 FIXME: Track which members are introduced by a dependent
16992 using-decl precisely, perhaps by performing another lookup
16993 from the substituted USING_DECL_SCOPE. */
16996 }
16997 else
16999 }
17001 /* Returns true iff (a less specialized version of) FN appeared in
17002 the old lookup set OLDFNS. */
17005 /* FN is a member function from a base class, introduced via a
17006 using-decl; if it might have been introduced by a dependent
17007 using-decl then just conservatively keep it, otherwise look
17008 in the old lookup set for FN exactly. */
17011 /* FN is a member function template from the current class;
17012 look in the old lookup set for the TEMPLATE_DECL from which
17013 it was specialized. */
17015 else
17016 /* FN is a non-template member function from the current class;
17017 look in the old lookup set for the FUNCTION_DECL from which
17018 it was specialized. */
17021 };
17026 {
17029 }
17033 /* Filter out from NEWFNS the member functions that weren't
17034 previously visible according to OLDFNS. */
17039 {
17041 filtered_size++;
17042 }
17048 }
17050 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
17051 expression on the left-hand side of the "." or "->" operator. We
17052 only do the lookup if we had a dependent BASELINK. Otherwise we
17053 adjust it onto the instantiated heirarchy. */
17055 static tree
17058 {
17070 {
17077 }
17085 {
17090 /* See maybe_dependent_member_ref. */
17092 {
17095 template_args);
17098 }
17101 /* Treat as-if non-dependent below. */
17106 complain);
17108 {
17109 /* Filter out from the new lookup set those functions which didn't
17110 appear in the original lookup set (in a less specialized form).
17111 This is needed to preserve the consistency of member lookup
17112 performed in an incomplete-class context, within which
17113 later-declared members ought to remain invisible. */
17116 binfo_type);
17118 }
17121 {
17127 }
17130 }
17131 else
17132 {
17133 /* We're going to overwrite pieces below, make a duplicate. */
17137 {
17138 /* The decl we found was from non-dependent scope, but we still need
17139 to update the binfos for the instantiated qualifying_scope. */
17143 }
17144 }
17146 /* If lookup found a single function, mark it as used at this point.
17147 (If lookup found multiple functions the one selected later by
17148 overload resolution will be marked as used at that point.) */
17150 {
17156 /* We might have instantiated an auto function. */
17158 }
17161 {
17162 /* Add back the template arguments, if present. */
17167 /* Update the conversion operator type. */
17169 }
17175 {
17177 qualifying_scope,
17178 object_type);
17180 /* We need to call adjust_result_of_qualified_name_lookup in case the
17181 destructor names a base class, but we unset BASELINK_QUALIFIED_P
17182 so that we still get virtual function binding. */
17184 }
17187 }
17189 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
17190 true if the qualified-id will be a postfix-expression in-and-of
17191 itself; false if more of the postfix-expression follows the
17192 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
17193 of "&". */
17195 static tree
17199 {
17200 tree expr;
17201 tree scope;
17202 tree name;
17204 tree template_args;
17209 /* Figure out what name to look up. */
17212 {
17221 }
17222 else
17223 {
17226 }
17228 /* Substitute into the qualifying scope. When there are no ARGS, we
17229 are just trying to simplify a non-dependent expression. In that
17230 case the qualifying scope may be dependent, and, in any case,
17231 substituting will not help. */
17234 {
17237 }
17238 else
17242 {
17244 /* We built one in tsubst_baselink. */
17246 else
17247 {
17250 template_args);
17252 QUALIFIED_NAME_IS_TEMPLATE
17254 }
17257 }
17260 {
17262 {
17263 /* A BIT_NOT_EXPR is used to represent a destructor. */
17265 {
17269 }
17270 else
17273 }
17274 else
17278 {
17280 {
17284 }
17286 }
17287 }
17290 {
17294 /* Remember that there was a reference to this entity. */
17297 }
17300 {
17306 }
17309 {
17310 /* We may be repeating a check already done during parsing, but
17311 if it was well-formed and passed then, it will pass again
17312 now, and if it didn't, we wouldn't have got here. The case
17313 we want to catch is when we couldn't tell then, and can now,
17314 namely when templ prior to substitution was an
17315 identifier. */
17321 complain);
17322 else
17324 }
17330 {
17331 expr = (adjust_result_of_qualified_name_lookup
17333 expr = (finish_qualified_id_expr
17337 }
17339 /* Expressions do not generally have reference type. */
17341 /* However, if we're about to form a pointer-to-member, we just
17342 want the referenced member referenced. */
17352 }
17354 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
17355 initializer, DECL is the substituted VAR_DECL. Other arguments are as
17356 for tsubst. */
17358 static tree
17361 {
17370 {
17372 {
17374 {
17379 }
17380 }
17382 {
17383 /* If we had an initializer but it
17384 instantiated to nothing,
17385 value-initialize the object. This will
17386 only occur when the initializer was a
17387 pack expansion where the parameter packs
17388 used in that expansion were of length
17389 zero. */
17395 }
17396 }
17399 }
17401 /* If T is a reference to a dependent member of the current instantiation C and
17402 we are trying to refer to that member in a partial instantiation of C,
17403 return a SCOPE_REF; otherwise, return NULL_TREE.
17405 This can happen when forming a C++17 deduction guide, as in PR96199. */
17407 static tree
17409 tree in_decl)
17410 {
17427 {
17436 complain);
17437 }
17442 {
17448 }
17451 {
17454 /* The TYPE_DECL for a typename has DECL_CONTEXT of the typename
17455 scope, but it doesn't need to be rewritten again. */
17459 }
17463 else
17466 }
17468 /* Helper function for tsubst_omp_clauses, used for instantiation of
17469 OMP_CLAUSE_DECL of clauses. */
17471 static tree
17474 {
17478 /* Handle OpenMP iterators. */
17482 {
17483 tree ret;
17486 else
17487 {
17491 {
17505 }
17509 }
17513 }
17515 /* Handle an OpenMP array section represented as a TREE_LIST (or
17516 OMP_CLAUSE_DOACROSS_KIND). An OMP_CLAUSE_DOACROSS (with a depend
17517 kind of OMP_CLAUSE_DOACROSS_SINK) can also be represented as a
17518 TREE_LIST. We can handle it exactly the same as an array section
17519 (purpose, value, and a chain), even though the nomenclature
17520 (low_bound, length, etc) is different. */
17522 {
17523 tree low_bound
17536 }
17538 {
17539 tree low_bound
17542 in_decl);
17550 length);
17551 }
17553 /* Undo convert_from_reference tsubst_expr could have called. */
17559 }
17561 /* Like tsubst_copy, but specifically for OpenMP clauses. */
17563 static tree
17566 {
17572 {
17578 {
17581 {
17587 }
17588 /* FALLTHRU */
17618 /* FALLTHRU */
17652 {
17655 {
17662 }
17663 else
17665 }
17692 {
17695 }
17700 else
17731 }
17734 {
17751 /* tsubst_expr on SCOPE_REF results in returning
17752 finish_non_static_data_member result. Undo that here. */
17756 {
17761 {
17765 CASE_CONVERT:
17774 /* FALLTHRU */
17778 }
17779 }
17785 {
17788 {
17791 }
17792 }
17796 }
17797 }
17801 {
17806 {
17809 }
17810 }
17812 }
17814 /* Like tsubst_expr, but unshare TREE_LIST nodes. */
17816 static tree
17818 tree in_decl)
17819 {
17820 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
17838 {
17841 else
17842 {
17846 }
17847 }
17852 #undef RECUR
17853 }
17855 /* Used to temporarily communicate the list of #pragma omp parallel
17856 clauses to #pragma omp for instantiation if they are combined
17857 together. */
17862 cp_decomp *);
17864 /* Substitute one OMP_FOR iterator. */
17866 static bool
17870 {
17871 #define RECUR(NODE) \
17872 tsubst_stmt ((NODE), args, complain, in_decl)
17884 {
17887 {
17892 {
17901 else
17903 {
17905 {
17911 }
17914 }
17915 }
17916 }
17920 }
17922 {
17923 /* We need to jump through some hoops to handle declarations in the
17924 init-statement, since we might need to handle auto deduction,
17925 but we need to keep control of initialization. */
17929 }
17930 else
17931 {
17933 {
17936 {
17940 {
17944 CASE_CONVERT:
17952 {
17955 }
17956 /* FALLTHRU */
17960 }
17961 }
17962 }
17963 else
17965 }
17967 {
17973 }
17974 else
17978 {
17984 NULL_TREE);
17985 else
17987 }
17990 {
17998 {
18003 }
18006 }
18016 {
18018 {
18019 /* Declare the variable, but don't let that initialize it. */
18024 }
18027 {
18031 {
18040 }
18041 else
18045 {
18050 }
18051 else
18055 }
18061 }
18064 {
18065 /* Declare and initialize the variable. */
18068 }
18070 {
18075 {
18077 {
18083 {
18086 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
18091 }
18094 {
18096 decl);
18098 }
18101 {
18103 decl);
18105 }
18106 else
18108 }
18111 }
18113 {
18116 ? OMP_CLAUSE_LASTPRIVATE
18121 {
18124 }
18125 }
18126 }
18129 {
18133 }
18134 else
18138 {
18149 {
18157 }
18158 else
18164 {
18170 }
18174 {
18182 }
18183 else
18189 }
18198 #undef RECUR
18199 }
18201 /* Helper function of tsubst_expr, find OMP_TEAMS inside
18202 of OMP_TARGET's body. */
18204 static tree
18206 {
18209 {
18218 }
18220 }
18222 /* Helper function for tsubst_expr. For decomposition declaration
18223 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
18224 also the corresponding decls representing the identifiers
18225 of the decomposition declaration. Return DECL if successful
18226 or error_mark_node otherwise, set *FIRST to the first decl
18227 in the list chained through DECL_CHAIN and *CNT to the number
18228 of such decls. */
18230 static tree
18233 {
18238 decl2
18243 {
18245 {
18248 }
18260 else
18261 {
18265 }
18272 {
18275 }
18276 else
18278 }
18281 }
18283 /* Return the proper local_specialization for init-capture pack DECL. */
18285 static tree
18287 {
18288 /* We handle normal pack captures by forwarding to the specialization of the
18289 captured parameter. We can't do that for pack init-captures; we need them
18290 to have their own local_specialization. We created the individual
18291 VAR_DECLs (if any) under build_capture_proxy, and we need to collect them
18292 when we process the DECL_EXPR for the pack init-capture in the template.
18293 So, how do we find them? We don't know the capture proxy pack when
18294 building the individual resulting proxies, and we don't know the
18295 individual proxies when instantiating the pack. What we have in common is
18296 the FIELD_DECL.
18298 So...when we instantiate the FIELD_DECL, we stick the result in
18299 local_specializations. Then at the DECL_EXPR we look up that result, see
18300 how many elements it has, synthesize the names, and look them up. */
18314 {
18319 }
18321 {
18326 else
18328 }
18330 }
18332 /* T is an operand of a template tree being substituted. Return whether
18333 T is dependent such that we should suppress some warnings that would
18334 make sense if the substituted expression were written directly, like
18335 template <int I> bool f() { return I == 2; }
18336 We don't want to warn when instantiating f that comparing two constants
18337 always has the same value.
18339 This is a more limited concept of dependence than instantiation-dependent;
18340 here we don't care whether substitution could fail. */
18342 static bool
18344 {
18353 }
18355 /* A superset of tsubst_expr that also handles statement trees. */
18357 static tree
18359 {
18360 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
18361 #define RECUR(NODE) \
18362 tsubst_stmt ((NODE), args, complain, in_decl)
18365 tree r;
18366 location_t loc;
18378 {
18380 {
18384 }
18403 else
18416 {
18421 }
18425 {
18427 tree init;
18433 {
18436 {
18440 {
18445 }
18447 }
18448 else
18449 {
18450 /* This is a non-dependent using-decl, and we'll have
18451 used the names it found during template parsing. We do
18452 not want to do the lookup again, because we might not
18453 find the things we found then. */
18456 /* We still need to push the bindings so that we can look up
18457 this name later. */
18460 }
18461 }
18464 {
18465 /* We're in tsubst_lambda_expr, we've already inserted a new
18466 capture proxy, so look it up and register it. */
18467 tree inst;
18469 {
18473 }
18475 {
18476 inst = (retrieve_local_specialization
18480 }
18481 else
18486 }
18493 /* Don't copy the old closure; we'll create a new one in
18494 tsubst_lambda_expr. */
18496 else
18497 {
18501 {
18502 /* By marking the declaration as instantiated, we avoid
18503 trying to instantiate it. Since instantiate_decl can't
18504 handle local variables, and since we've already done
18505 all that needs to be done, that's the right thing to
18506 do. */
18511 /* Anonymous aggregates are a special case. */
18514 {
18517 {
18521 }
18523 }
18528 {
18536 }
18537 else
18538 {
18553 {
18557 }
18562 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
18565 /* In a non-template function, VLA type declarations are
18566 handled in grokdeclarator; for templates, handle them
18567 now. */
18571 {
18575 asmspec_tree
18579 }
18582 decomp);
18586 }
18587 }
18588 }
18591 }
18601 {
18605 }
18610 {
18611 /* Construct another range_for, if this is not a final
18612 substitution (for inside a generic lambda of a
18613 template). Otherwise convert to a regular for. */
18615 stmt = (processing_template_decl
18626 {
18630 }
18634 unroll
18636 unroll);
18638 {
18645 }
18646 else
18655 }
18662 {
18666 }
18672 {
18676 }
18688 {
18694 }
18697 {
18698 /* We're partially instantiating a generic lambda, but the condition
18699 of the constexpr if is still dependent. Don't substitute into the
18700 branches now, just remember the template arguments. */
18708 }
18712 {
18717 }
18718 else
18719 {
18727 }
18733 {
18743 }
18751 else
18759 else
18780 {
18786 {
18791 }
18792 }
18796 {
18798 tree label;
18805 }
18811 /* Computed goto's must be tsubst'd into. On the other hand,
18812 non-computed gotos must not be; the identifier in question
18813 will have no binding. */
18815 else
18821 {
18838 }
18843 {
18848 }
18849 else
18850 {
18855 else
18862 else
18868 else
18870 }
18874 {
18878 {
18880 /* Prevent instantiate_decl from trying to instantiate
18881 this variable. We've already done all that needs to be
18882 done. */
18885 }
18890 }
18896 /* This is a partial instantiation, try again when full. */
18899 {
18900 /* Local classes are not independent templates; they are
18901 instantiated along with their containing function. And this
18902 way we don't have to deal with pushing out of one local class
18903 to instantiate a member of another local class. */
18904 /* Closures are handled by the LAMBDA_EXPR. */
18920 }
18924 {
18941 }
18970 {
18977 }
18993 {
19007 in_decl);
19009 {
19016 }
19027 any_range_for
19034 {
19043 }
19044 else
19049 else
19056 else
19057 {
19065 }
19068 t));
19070 }
19076 /* FALLTHRU */
19086 in_decl);
19088 {
19093 }
19094 else
19095 {
19099 }
19104 {
19106 "%<#pragma omp critical%> with %<hint%> clause requires "
19109 }
19120 {
19123 {
19128 }
19129 else
19130 {
19134 }
19136 }
19137 else
19139 OMP_CLAUSE_DEPEND_INVALID,
19148 ? C_ORT_ACC
19167 {
19170 /* For combined target teams, ensure the num_teams and
19171 thread_limit clause expressions are evaluated on the host,
19172 before entering the target construct. */
19181 {
19184 tf_none);
19191 OMP_CLAUSE_FIRSTPRIVATE);
19195 }
19196 }
19233 {
19237 }
19238 else
19250 /* FALLTHRU */
19268 {
19274 {
19277 }
19279 {
19283 {
19286 }
19291 }
19292 else
19293 {
19296 }
19301 }
19302 else
19303 {
19310 {
19313 }
19316 {
19321 {
19324 }
19326 {
19330 {
19333 }
19338 }
19339 else
19340 {
19343 }
19347 }
19348 else
19349 {
19353 }
19357 }
19361 {
19367 {
19371 {
19376 }
19380 }
19381 else
19382 {
19387 }
19388 }
19392 {
19396 }
19409 /* If the first operand was a statement, we're done with it. */
19414 complain));
19423 }
19426 out:
19429 #undef RECUR
19430 #undef RETURN
19431 }
19433 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
19434 function. For description of the body see comment above
19435 cp_parser_omp_declare_reduction_exprs. */
19437 static void
19439 {
19445 tree_stmt_iterator tsi;
19456 {
19463 /* tsubsting a local var_decl leaves DECL_CONTEXT null, as we
19464 expect to be pushing it. */
19476 }
19478 {
19498 }
19499 }
19501 /* T is a postfix-expression that is not being used in a function
19502 call. Return the substituted version of T. */
19504 static tree
19506 tsubst_flags_t complain,
19507 tree in_decl)
19508 {
19512 else
19516 }
19518 /* Subroutine of tsubst_lambda_expr: add the FIELD/INIT capture pair to the
19519 LAMBDA_EXPR_CAPTURE_LIST passed in LIST. Do deduction for a previously
19520 dependent init-capture. EXPLICIT_P is true if the original list had
19521 explicit captures. */
19523 static void
19525 tsubst_flags_t complain)
19526 {
19528 {
19531 {
19535 }
19542 }
19545 }
19547 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
19548 instantiation context. Instantiating a pack expansion containing a lambda
19549 might result in multiple lambdas all based on the same lambda in the
19550 template. */
19552 tree
19554 {
19568 else
19579 {
19584 else
19596 {
19597 /* For a VLA, simply tsubsting the field type won't work, we need to
19598 go through add_capture again. XXX do we want to do this for all
19599 captures? */
19600 tree name = (get_identifier
19609 }
19616 {
19617 /* Remember these for when we've pushed local_specializations. */
19620 }
19626 {
19635 complain);
19636 }
19637 else
19638 {
19644 }
19645 }
19654 /* If we're pushed into another scope (PR105652), fix it. */
19659 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
19676 {
19679 }
19682 {
19685 }
19689 else
19690 {
19691 /* The body of a lambda-expression is not a subexpression of the
19692 enclosing expression. Parms are to have DECL_CHAIN tsubsted,
19693 which would be skipped if cp_unevaluated_operand. */
19694 cp_evaluated ev;
19696 /* Fix the type of 'this'.
19697 For static and xobj member functions we use this to transport the
19698 lambda's closure type. It appears that in the regular case the
19699 object parameter is still pulled off, and then re-added again anyway.
19700 So perhaps we could do something better here? */
19704 tree inst = (oldtmpl
19709 {
19712 }
19718 /* Let finish_function set this. */
19724 else
19725 /* Still increment function_depth so that we don't GC in the
19726 middle of an expression. */
19736 /* Now record them for lookup_init_capture_pack. */
19739 {
19743 }
19749 {
19750 /* We might not partially instantiate some parts of the function, so
19751 copy these flags from the original template. */
19757 }
19759 /* [temp.deduct] A lambda-expression appearing in a function type or a
19760 template parameter is not considered part of the immediate context for
19761 the purposes of template argument deduction. */
19766 /* We already have a body block from start_lambda_function, we don't
19767 need another to confuse NRV (91217). */
19778 else
19781 /* The capture list was built up in reverse order; fix that now. */
19788 }
19790 out:
19796 }
19798 /* Subroutine of maybe_fold_fn_template_args. */
19800 static bool
19802 {
19805 {
19811 {
19814 }
19819 {
19823 }
19824 }
19827 }
19829 /* Try to do constant evaluation of any explicit template arguments in FN
19830 before overload resolution, to get any errors only once. Return true iff
19831 we didn't have any problems folding. */
19833 static bool
19835 {
19853 }
19855 /* Helper function for tsubst_expr CALL_EXPR and ARRAY_REF handling. */
19857 static void
19860 {
19863 {
19868 else
19869 {
19870 /* Expand the pack expansion and push each entry onto CALL_ARGS. */
19873 {
19878 {
19883 }
19884 }
19885 else
19886 /* A partial substitution. Add one entry. */
19888 }
19889 }
19890 }
19892 /* Like tsubst but deals with expressions and performs semantic
19893 analysis. */
19895 tree
19897 {
19898 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
19899 #define RECUR(NODE) \
19900 tsubst_expr (NODE, args, complain, in_decl)
19903 location_t save_loc;
19912 /* N3276 decltype magic only applies to calls at the top level or on the
19913 right side of a comma. */
19917 /* This flag only applies to id-expressions at the top level, and
19918 controls resolution thereof. */
19927 {
19930 /* Fall through. */
19932 {
19933 tree decl;
19934 cp_id_kind idk;
19938 {
19941 }
19946 /* Look up the name. */
19949 /* By convention, expressions use ERROR_MARK_NODE to indicate
19950 failure, not NULL_TREE. */
19964 input_location);
19968 {
19972 }
19974 }
19977 {
19978 tree object;
19984 else
19993 {
19998 }
20001 {
20008 /* If we built a function concept check, return the underlying
20009 template-id. So we can evaluate it as a function call. */
20014 }
20017 {
20022 complain);
20026 }
20029 {
20032 }
20033 else
20045 {
20046 /* C++20 P0846: we can encounter an IDENTIFIER_NODE here when
20047 name lookup found nothing when parsing the template name. */
20050 }
20051 else
20053 }
20056 {
20060 {
20061 /* A type conversion to reference type will be enclosed in
20062 such an indirect ref, but the substitution of the cast
20063 will have also added such an indirect ref. */
20065 }
20066 else
20075 }
20078 {
20082 }
20085 {
20089 {
20094 }
20096 {
20101 }
20108 flags));
20109 }
20112 {
20118 }
20125 {
20126 tree type;
20140 {
20160 }
20163 }
20166 {
20170 }
20182 {
20185 }
20187 {
20191 }
20192 /* Fall through. */
20207 {
20214 }
20217 /* convert_like should have created an IMPLICIT_CONV_EXPR. */
20228 else
20230 in_decl);
20265 {
20266 /* If either OP0 or OP1 was value- or type-dependent, suppress
20267 warnings that depend on the range of the types involved. */
20281 tree r = build_x_binary_op
20283 op0,
20285 ? ERROR_MARK
20287 op1,
20289 ? ERROR_MARK
20298 }
20301 {
20309 }
20313 {
20318 }
20319 else
20333 {
20335 releasing_vec index_exp_list;
20338 tree r;
20344 else
20349 }
20355 {
20361 {
20365 }
20367 {
20371 }
20373 }
20378 {
20387 /* We only want to compute the number of arguments. */
20390 else
20397 {
20399 /* Set TREE_USED for the benefit of -Wunused. */
20403 }
20411 {
20414 else
20422 else
20427 }
20428 else
20430 }
20431 /* Fall through */
20434 {
20435 tree r;
20443 {
20444 /* When there are no ARGS, we are trying to evaluate a
20445 non-dependent expression from the parser. Trying to do
20446 the substitutions may not work. */
20449 }
20450 else
20451 {
20456 else
20460 }
20465 else
20470 {
20472 {
20474 {
20478 }
20479 else
20483 }
20485 }
20487 }
20490 {
20498 }
20512 {
20517 tree r = build_x_modify_expr
20521 /* TREE_NO_WARNING must be set if either the expression was
20522 parenthesized or it uses an operator such as >>= rather
20523 than plain assignment. In the former case, it was already
20524 set and must be copied. In the latter case,
20525 build_x_modify_expr sets it and it must not be reset
20526 here. */
20531 }
20536 /* Remember that there was a reference to this entity. */
20543 {
20548 tree ret;
20555 else
20556 {
20560 }
20562 /* If there was an initializer in the original tree, but it
20563 instantiated to an empty list, then we should pass a
20564 non-NULL empty vector to tell build_new that it was an
20565 empty initializer() rather than no initializer. This can
20566 only happen when the initializer is a pack expansion whose
20567 parameter packs are of length zero. */
20572 else
20573 {
20577 else
20578 {
20581 }
20582 }
20584 /* Avoid passing an enclosing decl to valid_array_size_p. */
20591 complain);
20599 }
20602 {
20608 complain));
20609 }
20612 {
20616 op0,
20620 }
20623 {
20624 tree function;
20628 tree ret;
20631 /* Internal function with no arguments. */
20635 /* When we parsed the expression, we determined whether or
20636 not Koenig lookup should be performed. */
20639 {
20642 }
20644 {
20649 }
20653 {
20655 in_decl);
20657 {
20664 }
20665 else
20668 }
20673 {
20674 /* Do nothing; calling tsubst_expr on an identifier
20675 would incorrectly perform unqualified lookup again.
20677 Note that we can also have an IDENTIFIER_NODE if the earlier
20678 unqualified lookup found a dependent local extern declaration
20679 (as per finish_call_expr); in that case koenig_p will be false
20680 and we do want to do the lookup again to find the substituted
20681 declaration. */
20686 }
20687 else
20688 {
20690 {
20696 }
20697 else
20702 /* Avoid error about taking the address of a constructor. */
20707 /* When KOENIG_P, we don't want to mark_used the callee before
20708 augmenting the overload set via ADL, so during this initial
20709 substitution we disable mark_used by setting tf_conv (68942). */
20715 }
20718 releasing_vec call_args;
20721 /* Stripped-down processing for a call in a thunk. Specifically, in
20722 the thunk template for a generic lambda. */
20724 {
20725 /* Now that we've expanded any packs, the number of call args
20726 might be different. */
20730 {
20737 }
20738 /* We aren't going to do normal overload resolution, so force the
20739 template-id to resolve. */
20742 {
20743 /* In a thunk, pass through args directly, without any
20744 conversions. */
20749 }
20751 {
20752 /* If there are no other args, just push 'this'. */
20755 else
20756 {
20757 /* Otherwise, shift the other args over to make room. */
20763 }
20764 }
20767 /* The thunk location is not interesting. */
20774 }
20776 /* We do not perform argument-dependent lookup if normal
20777 lookup finds a non-function, in accordance with the
20778 resolution of DR 218. */
20781 /* If lookup found a member function, the Koenig lookup is
20782 not appropriate, even if an unqualified-name was used
20783 to denote the function. */
20786 /* C++20 P0846: Lookup found nothing. */
20789 /* Only do this when substitution turns a dependent call
20790 into a non-dependent call. */
20802 {
20807 {
20808 /* For backwards compatibility and good diagnostics, try
20809 the unqualified lookup again if we aren't in SFINAE
20810 context. */
20816 {
20819 "and no declarations were found by "
20820 "argument-dependent lookup at the point "
20825 /* In a lambda fn, we have to be careful to not
20826 introduce new this captures. Legacy code can't
20827 be using lambdas anyway, so it's ok to be
20828 stricter. Be strict with C++20 template-id ADL too.
20829 And be strict if we're already failing anyway. */
20835 else
20839 {
20850 {
20853 "declarations in dependent base %qT are "
20859 else
20863 }
20864 else
20866 "%qD declared here, later in the "
20870 }
20873 }
20874 }
20876 {
20880 }
20881 }
20883 /* Remember that there was a reference to this entity. */
20892 /* Put back tf_decltype for the actual call. */
20897 {
20901 {
20903 "wrong number of arguments to "
20906 }
20907 else
20915 {
20917 "wrong number of arguments to "
20921 }
20925 complain);
20931 {
20933 complain);
20937 }
20942 {
20944 "wrong number of arguments to "
20947 }
20948 else
20949 {
20954 {
20957 }
20960 }
20964 /* Unsupported internal function with arguments. */
20966 }
20971 complain);
20973 {
20974 /* FUNCTION is a template-id referring to a concept definition. */
20979 /* Calls to standard and variable concepts should have been
20980 previously diagnosed. */
20983 /* Ensure the result is wrapped as a call expression. */
20985 }
20986 else
20989 koenig_p,
20990 complain);
20993 {
20999 {
21003 }
21005 /* This also suppresses -Wredundant-move. */
21007 }
21010 }
21013 {
21020 {
21022 {
21027 }
21028 else
21029 {
21034 }
21036 }
21037 else
21038 {
21041 }
21046 }
21049 {
21054 input_location));
21055 }
21061 {
21062 tree object;
21063 tree object_type;
21064 tree member;
21065 tree r;
21069 /* Remember that there was a reference to this entity. */
21080 else
21087 {
21090 }
21092 {
21094 complain);
21098 }
21102 {
21104 {
21109 {
21112 }
21114 {
21119 }
21120 }
21121 }
21124 {
21125 /* Lookup the template functions now that we know what the
21126 scope is. */
21133 {
21136 args);
21137 member = (adjust_result_of_qualified_name_lookup
21139 object_type));
21140 }
21141 else
21142 {
21144 input_location);
21146 }
21147 }
21151 {
21153 {
21157 else
21160 }
21162 }
21166 complain);
21170 }
21177 {
21184 tree r;
21193 /* We do not want to process the index of aggregate
21194 initializers as they are identifier nodes which will be
21195 looked up by digest_init. */
21199 {
21202 }
21207 {
21209 /* An identifier index is looked up in the type
21210 being initialized, not the current scope. */
21215 {
21216 /* Substitute into the pack expansion. */
21218 in_decl);
21222 ;
21224 /* Just move the argument into place. */
21226 else
21227 {
21228 /* Update the length of the final CONSTRUCTOR
21229 arguments vector, and note that we will need to
21230 copy.*/
21233 }
21234 }
21235 else
21237 }
21240 {
21245 {
21247 {
21252 }
21253 else
21255 }
21256 }
21264 {
21269 }
21273 }
21276 {
21279 {
21282 }
21283 else
21284 {
21287 }
21288 }
21295 tree r;
21300 {
21301 /* Local specialization will usually have been created when
21302 we instantiated the DECL_EXPR_DECL. */
21305 {
21306 /* We're in a generic lambda referencing a local extern
21307 from an outer block-scope of a non-template. */
21310 }
21311 }
21316 {
21318 {
21319 /* We get here for a use of 'this' in an NSDMI. */
21323 /* This can happen for a parameter name used later in a function
21324 declaration (such as in a late-specified return type). Just
21325 make a dummy decl, since it's only used for its type. */
21328 /* Give it the template pattern as its context; its true context
21329 hasn't been instantiated yet and this is good enough for
21330 mangling. */
21332 }
21334 {
21335 /* First try name lookup to find the instantiation. */
21338 {
21340 {
21341 /* During error-recovery we may find a non-variable,
21342 even an OVERLOAD: just bail out and avoid ICEs and
21343 duplicate diagnostics (c++/62207). */
21346 }
21348 {
21349 /* Make sure the one we found is the one we want. */
21353 }
21354 }
21358 else
21359 {
21360 /* This can happen for a variable used in a
21361 late-specified return type of a local lambda, or for a
21362 local static or constant. Building a new VAR_DECL
21363 should be OK in all those cases. */
21366 /* Avoid infinite recursion (79640). */
21369 {
21370 /* We can't call cp_finish_decl, so handle the
21371 initializer by hand. */
21386 }
21388 || processing_contract_condition
21395 }
21396 /* Remember this for subsequent uses. */
21399 }
21402 }
21403 else
21410 {
21411 /* ??? We're doing a subset of finish_id_expression here. */
21413 /* Replace an evaluated use of the thread_local variable with
21414 a call to its wrapper. */
21420 /* If the original type was a reference, we'll be wrapped in
21421 the appropriate INDIRECT_REF. */
21423 }
21427 {
21428 tree enum_type;
21429 tree v;
21436 /* Unfortunately, we cannot just call lookup_name here.
21437 Consider:
21439 template <int I> int f() {
21440 enum E { a = I };
21441 struct S { void g() { E e = a; } };
21442 };
21444 When we instantiate f<7>::S::g(), say, lookup_name is not
21445 clever enough to find f<7>::a. */
21446 enum_type
21456 /* We didn't find the name. That should never happen; if
21457 name-lookup found it during preliminary parsing, we
21458 should find it again here during instantiation. */
21461 }
21465 {
21466 tree ctx;
21471 {
21474 {
21478 }
21480 }
21481 }
21496 {
21497 /* Template template argument like the following example need
21498 special treatment:
21500 template <template <class> class TT> struct C {};
21501 template <class T> struct D {
21502 template <class U> struct E {};
21503 C<E> c; // #1
21504 };
21505 D<int> d; // #2
21507 We are processing the template argument `E' in #1 for
21508 the template instantiation #2. Originally, `E' is a
21509 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
21510 have to substitute this with one having context `D<int>'. */
21515 }
21516 else
21517 /* Ordinary template template argument. */
21525 /* We shouldn't have built any of these during initial template
21526 generation. Instead, they should be built during instantiation
21527 in response to the saved STMT_IS_FULL_EXPR_P setting. */
21531 {
21541 }
21559 {
21560 /* Instantiate any typedefs in the type. */
21565 }
21568 {
21572 {
21575 }
21577 }
21580 /* These can sometimes show up in a partial instantiation, but never
21581 involve template parms. */
21597 /* ??? There's no point in copying it for now, but maybe some
21598 day it will contain more information, such as a pointer back
21599 to the containing function, inlined copy or so. */
21611 {
21615 }
21618 {
21619 tree object_ptr
21624 }
21631 {
21635 else
21641 }
21644 {
21653 /* If the resulting list of expression statement is empty,
21654 fold it further into void_node. */
21659 }
21662 {
21664 {
21665 /* We don't have a full set of template arguments yet; don't touch
21666 the lambda at all. */
21669 }
21673 }
21682 else
21683 /* Recreate the PAREN_EXPR from __builtin_assoc_barrier. */
21684 {
21688 }
21691 {
21696 complain));
21697 }
21700 {
21703 }
21706 /* No need to substitute further, a RANGE_EXPR will always be built
21707 with constant operands. */
21712 {
21716 /* We need to do this here as well as in tsubst_copy so we get the
21717 other tsubst_copy_and_build semantics for a PARM_DECL operand. */
21722 /* force_paren_expr can also create a VIEW_CONVERT_EXPR. */
21725 /* Otherwise, we're dealing with a wrapper to make a C++20 template
21726 parameter object const. */
21729 {
21730 /* The template argument is not const, presumably because
21731 it is still dependent, and so not the const template parm
21732 object. */
21736 {
21737 /* Don't add a wrapper to these. */
21740 }
21741 else
21742 /* Do add a wrapper otherwise (in particular, if op is
21743 another TEMPLATE_PARM_INDEX). */
21745 }
21747 }
21750 {
21757 op3);
21760 }
21763 /* Handle Objective-C++ constructs, if appropriate. */
21767 /* We shouldn't get here, but keep going if !flag_checking. */
21771 }
21773 #undef RECUR
21774 #undef RETURN
21775 out:
21778 }
21780 /* Verify that the instantiated ARGS are valid. For type arguments,
21781 make sure that the type's linkage is ok. For non-type arguments,
21782 make sure they are constants if they are integral or enumerations.
21783 Emit an error under control of COMPLAIN, and return TRUE on error. */
21785 static bool
21787 {
21791 {
21801 }
21803 {
21804 /* [basic.link]: A name with no linkage (notably, the name
21805 of a class or enumeration declared in a local scope)
21806 shall not be used to declare an entity with linkage.
21807 This implies that names with no linkage cannot be used as
21808 template arguments
21810 DR 757 relaxes this restriction for C++0x. */
21815 {
21816 /* DR 488 makes use of a type with no linkage cause
21817 type deduction to fail. */
21819 {
21822 else
21825 }
21827 }
21828 /* In order to avoid all sorts of complications, we do not
21829 allow variably-modified types as template arguments. */
21831 {
21835 }
21836 }
21837 /* Class template and alias template arguments should be OK. */
21839 ;
21840 /* A non-type argument of integral or enumerated type must be a
21841 constant. */
21846 {
21850 }
21852 }
21854 static bool
21856 {
21861 {
21864 }
21868 }
21870 /* Call mark_used on each entity within the non-type template arguments in
21871 ARGS for an instantiation of TMPL, to ensure that each such entity is
21872 considered odr-used (and therefore marked for instantiation) regardless of
21873 whether the specialization was first formed in a template context (which
21874 inhibits mark_used).
21876 This function assumes push_to_top_level has been called beforehand. */
21878 static void
21880 {
21881 /* It suffices to do this only when instantiating a primary template. */
21885 /* We already marked outer arguments when specializing the context. */
21889 {
21890 /* A (pointer/reference to) function or variable NTTP argument. */
21893 {
21899 {
21900 /* Pass tf_none to avoid duplicate diagnostics: if this call
21901 fails then an earlier call to mark_used for this argument
21902 must have also failed and emitted a diagnostic. */
21905 }
21906 }
21907 /* A class NTTP argument. */
21910 {
21913 {
21916 }
21918 };
21921 }
21922 }
21923 }
21925 /* We're out of SFINAE context now, so generate diagnostics for the access
21926 errors we saw earlier when instantiating D from TMPL and ARGS. */
21928 static void
21930 {
21942 }
21944 /* Instantiate the indicated variable, function, or alias template TMPL with
21945 the template arguments in TARG_PTR. */
21947 tree
21949 {
21953 tree fndecl;
21954 tree gen_tmpl;
21960 /* The other flags are not relevant anymore here, especially tf_partial
21961 shouldn't be set. For instance, we may be called while doing a partial
21962 substitution of a template variable, but the type of the variable
21963 template may be auto, in which case we will call do_auto_deduction
21964 in mark_used (which clears tf_partial) and the auto must be properly
21965 reduced at that time for the deduction to work. */
21973 /* If this function is a clone, handle it specially. */
21975 {
21976 tree spec;
21977 tree clone;
21979 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
21980 DECL_CLONED_FUNCTION. */
21986 /* Look for the clone. */
21990 /* We should always have found the clone by now. */
21993 }
21998 /* Check to see if we already have this specialization. */
22002 /* targ_ptr only has the innermost template args, so add the outer ones
22003 from tmpl, which could be either a partial instantiation or gen_tmpl (in
22004 the case of a non-dependent call within a template definition). */
22005 targ_ptr = (add_outermost_template_args
22007 targ_ptr));
22013 || ((fndecl
22019 {
22021 {
22025 }
22027 }
22030 complain))
22033 /* We are building a FUNCTION_DECL, during which the access of its
22034 parameters and return types have to be checked. However this
22035 FUNCTION_DECL which is the desired context for access checking
22036 is not built yet. We solve this chicken-and-egg problem by
22037 deferring all checks until we have the FUNCTION_DECL. */
22040 /* Instantiation of the function happens in the context of the function
22041 template, not the context of the overload resolution we're doing. */
22043 /* If there are dependent arguments, e.g. because we're doing partial
22044 ordering, make sure processing_template_decl stays set. */
22048 {
22049 tree ctx;
22051 /* If the context of the partially instantiated template is
22052 already non-dependent, then we might as well use it. */
22054 else
22058 }
22065 {
22066 /* We need to determine if we're using a partial or explicit
22067 specialization now, because the type of the variable could be
22068 different. */
22074 {
22080 }
22081 }
22083 /* Substitute template parameters to obtain the specialization. */
22091 {
22094 }
22096 /* The DECL_TI_TEMPLATE should always be the immediate parent
22097 template, not the most general template. */
22101 /* Now that we we've formed this variable template specialization,
22102 remember the result of most_specialized_partial_spec for it. */
22111 /* Now we know the specialization, compute access previously
22112 deferred. Do no access control for inheriting constructors,
22113 as we already checked access for the inherited constructor. */
22116 {
22121 }
22124 /* If we've just instantiated the main entry point for a function,
22125 instantiate all the alternate entry points as well. We do this
22126 by cloning the instantiation of the main entry point, not by
22127 instantiating the template clones. */
22133 {
22135 {
22136 /* Remember to reinstantiate when we're out of SFINAE so the user
22137 can see the errors. */
22139 }
22141 }
22144 }
22146 /* Instantiate the alias template TMPL with ARGS. Also push a template
22147 instantiation level, which instantiate_template doesn't do because
22148 functions and variables have sufficient context established by the
22149 callers. */
22151 static tree
22153 {
22162 /* FIXME check for satisfaction in check_instantiated_args. */
22164 {
22166 {
22167 auto_diagnostic_group d;
22170 }
22172 }
22180 {
22181 /* An alias template specialization can be dependent
22182 even if its underlying type is not. */
22185 /* Sometimes a dependent alias spec is equivalent to its expansion,
22186 sometimes not. So always use structural_comptypes. */
22188 }
22191 }
22193 /* PARM is a template parameter pack for FN. Returns true iff
22194 PARM is used in a deducible way in the argument list of FN. */
22196 static bool
22198 {
22201 {
22203 tree packs;
22209 {
22210 /* The template parameter pack is used in a function parameter
22211 pack. If this is the end of the parameter list, the
22212 template parameter pack is deducible. */
22215 else
22216 /* Otherwise, not. Well, it could be deduced from
22217 a non-pack parameter, but doing so would end up with
22218 a deduction mismatch, so don't bother. */
22220 }
22221 }
22222 /* The template parameter pack isn't used in any function parameter
22223 packs, but it might be used deeper, e.g. tuple<Args...>. */
22225 }
22227 /* Subroutine of fn_type_unification: check non-dependent parms for
22228 convertibility. */
22230 static int
22235 {
22236 /* Non-constructor methods need to leave a conversion for 'this', which
22237 isn't included in nargs here. */
22243 {
22249 /* For a function parameter pack that occurs at the end of the
22250 parameter-declaration-list, the type A of each remaining
22251 argument of the call is compared with the type P of the
22252 declarator-id of the function parameter pack. */
22258 /* For a function parameter pack that does not occur at the
22259 end of the parameter-declaration-list, the type of the
22260 parameter pack is a non-deduced context. */
22264 {
22272 }
22275 }
22278 }
22280 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
22281 NARGS elements of the arguments that are being used when calling
22282 it. TARGS is a vector into which the deduced template arguments
22283 are placed.
22285 Returns either a FUNCTION_DECL for the matching specialization of FN or
22286 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
22287 true, diagnostics will be printed to explain why it failed.
22289 If FN is a conversion operator, or we are trying to produce a specific
22290 specialization, RETURN_TYPE is the return type desired.
22292 The EXPLICIT_TARGS are explicit template arguments provided via a
22293 template-id.
22295 The parameter STRICT is one of:
22297 DEDUCE_CALL:
22298 We are deducing arguments for a function call, as in
22299 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
22300 deducing arguments for a call to the result of a conversion
22301 function template, as in [over.call.object].
22303 DEDUCE_CONV:
22304 We are deducing arguments for a conversion function, as in
22305 [temp.deduct.conv].
22307 DEDUCE_EXACT:
22308 We are deducing arguments when doing an explicit instantiation
22309 as in [temp.explicit], when determining an explicit specialization
22310 as in [temp.expl.spec], or when taking the address of a function
22311 template, as in [temp.deduct.funcaddr]. */
22313 tree
22315 tree explicit_targs,
22316 tree targs,
22319 tree return_type,
22320 unification_kind_t strict,
22325 {
22326 tree parms;
22327 tree fntype;
22332 /* type_unification_real will pass back any access checks from default
22333 template argument substitution. */
22335 /* We don't have all the template args yet. */
22348 full_targs = (add_outermost_template_args
22350 targs));
22355 /* In C++0x, it's possible to have a function template whose type depends
22356 on itself recursively. This is most obvious with decltype, but can also
22357 occur with enumeration scope (c++/48969). So we need to catch infinite
22358 recursion and reject the substitution at deduction time; this function
22359 will return error_mark_node for any repeated substitution.
22361 This also catches excessive recursion such as when f<N> depends on
22362 f<N-1> across all integers, and returns error_mark_node for all the
22363 substitutions back up to the initial one.
22365 This is, of course, not reentrant. */
22374 {
22375 /* [temp.deduct]
22377 The specified template arguments must match the template
22378 parameters in kind (i.e., type, nontype, template), and there
22379 must not be more arguments than there are parameters;
22380 otherwise type deduction fails.
22382 Nontype arguments must match the types of the corresponding
22383 nontype template parameters, or must be convertible to the
22384 types of the corresponding nontype parameters as specified in
22385 _temp.arg.nontype_, otherwise type deduction fails.
22387 All references in the function type of the function template
22388 to the corresponding template parameters are replaced by the
22389 specified template argument values. If a substitution in a
22390 template parameter or in the function type of the function
22391 template results in an invalid type, type deduction fails. */
22402 explicit_targs);
22404 /* Adjust any explicit template arguments before entering the
22405 substitution context. */
22406 explicit_targs
22413 /* Substitute the explicit args into the function type. This is
22414 necessary so that, for instance, explicitly declared function
22415 arguments can match null pointed constants. If we were given
22416 an incomplete set of explicit args, we must not do semantic
22417 processing during substitution as we could create partial
22418 instantiations. */
22420 {
22425 /* Dig out the actual parm. */
22428 {
22431 }
22433 {
22436 }
22439 /* No explicit argument for this template parameter. */
22442 {
22443 /* Mark the argument pack as "incomplete". We could
22444 still deduce more arguments during unification.
22445 We remove this mark in type_unification_real. */
22450 /* We have some incomplete argument packs. */
22452 }
22453 }
22456 {
22458 {
22461 }
22464 /* Ignore any access checks; we'll see them again in
22465 instantiate_template and they might have the wrong
22466 access path at this point. */
22477 }
22479 /* Place the explicitly specified arguments in TARGS. */
22485 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
22487 }
22490 {
22496 }
22501 /* Never do unification on the 'this' parameter. */
22505 {
22506 /* We're deducing for a call to the result of a template conversion
22507 function. The parms we really want are in return_type. */
22511 }
22513 {
22515 }
22517 /* We allow incomplete unification without an error message here
22518 because the standard doesn't seem to explicitly prohibit it. Our
22519 callers must be ready to deal with unification failures in any
22520 event. */
22522 /* If we aren't explaining yet, push tinst context so we can see where
22523 any errors (e.g. from class instantiations triggered by instantiation
22524 of default template arguments) come from. If we are explaining, this
22525 context is redundant. */
22527 {
22530 }
22540 /* Now that we have bindings for all of the template arguments,
22541 ensure that the arguments deduced for the template template
22542 parameters have compatible template parameter lists. We cannot
22543 check this property before we have deduced all template
22544 arguments, because the template parameter types of a template
22545 template parameter might depend on prior template parameters
22546 deduced after the template template parameter. The following
22547 ill-formed example illustrates this issue:
22549 template<typename T, template<T> class C> void f(C<5>, T);
22551 template<int N> struct X {};
22553 void g() {
22554 f(X<5>(), 5l); // error: template argument deduction fails
22555 }
22557 The template parameter list of 'C' depends on the template type
22558 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
22559 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
22560 time that we deduce 'C'. */
22563 {
22566 }
22568 deduced:
22570 /* As a refinement of CWG2369, check first and foremost non-dependent
22571 conversions that we know are not going to induce template instantiation
22572 (PR99599). */
22574 && incomplete
22580 /* CWG2369: Check satisfaction before non-deducible conversions. */
22582 {
22586 }
22588 /* DR 1391: All parameters have args, now check non-dependent parms for
22589 convertibility. We don't do this if all args were explicitly specified,
22590 as the standard says that we substitute explicit args immediately. */
22597 /* All is well so far. Now, check:
22599 [temp.deduct]
22601 When all template arguments have been deduced, all uses of
22602 template parameters in nondeduced contexts are replaced with
22603 the corresponding deduced argument values. If the
22604 substitution results in an invalid type, as described above,
22605 type deduction fails. */
22607 {
22610 }
22612 /* Also collect access checks from the instantiation. */
22625 /* Now perform any access checks encountered during substitution. */
22632 /* If we're looking for an exact match, check that what we got
22633 is indeed an exact match. It might not be if some template
22634 parameters are used in non-deduced contexts. But don't check
22635 for an exact match if we have dependent template arguments;
22636 in that case we're doing partial ordering, and we already know
22637 that we have two candidates that will provide the actual type. */
22639 {
22643 tree sarg
22649 {
22653 }
22655 /* add_candidates uses DEDUCE_EXACT for x.operator foo(), but args
22656 doesn't contain the trailing void, and conv fns are always (). */
22658 {
22662 }
22663 }
22665 /* After doing deduction with the inherited constructor, actually return an
22666 instantiation of the inheriting constructor. */
22672 fail:
22675 {
22677 /* Reset once we're all the way out. */
22679 }
22682 }
22684 /* Returns true iff PARM is a forwarding reference in the context of
22685 template argument deduction for TMPL. */
22687 static bool
22689 {
22690 /* [temp.deduct.call], "A forwarding reference is an rvalue reference to a
22691 cv-unqualified template parameter ..." */
22696 {
22698 /* [temp.deduct.call], "... that does not represent a template parameter
22699 of a class template (during class template argument deduction)." */
22703 {
22704 /* Since the template parameters of a synthesized guide consist of
22705 the template parameters of the class template followed by those of
22706 the constructor (if any), we can tell if PARM represents a template
22707 parameter of the class template by comparing its index with the
22708 arity of the class template. */
22713 }
22715 }
22717 }
22719 /* Adjust types before performing type deduction, as described in
22720 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
22721 sections are symmetric. PARM is the type of a function parameter
22722 or the return type of the conversion function. ARG is the type of
22723 the argument passed to the call, or the type of the value
22724 initialized with the result of the conversion function.
22725 ARG_EXPR is the original argument expression, which may be null. */
22727 static int
22729 unification_kind_t strict,
22732 tree arg_expr)
22733 {
22737 {
22742 /* [temp.deduct.conv] First remove a reference type on parm.
22743 DRs 322 & 976 affected this. */
22747 /* Swap PARM and ARG throughout the remainder of this
22748 function; the handling is precisely symmetric since PARM
22749 will initialize ARG rather than vice versa. */
22755 /* Core issue #873: Do the DR606 thing (see below) for these cases,
22756 too, but here handle it by stripping the reference from PARM
22757 rather than by adding it to ARG. */
22762 /* Nothing else to do in this case. */
22767 }
22770 {
22771 /* [temp.deduct.call]
22773 If P is not a reference type:
22775 --If A is an array type, the pointer type produced by the
22776 array-to-pointer standard conversion (_conv.array_) is
22777 used in place of A for type deduction; otherwise,
22779 --If A is a function type, the pointer type produced by
22780 the function-to-pointer standard conversion
22781 (_conv.func_) is used in place of A for type deduction;
22782 otherwise,
22784 --If A is a cv-qualified type, the top level
22785 cv-qualifiers of A's type are ignored for type
22786 deduction. */
22791 else
22793 }
22795 /* [temp.deduct.call], "If P is a forwarding reference and the argument is
22796 an lvalue, the type 'lvalue reference to A' is used in place of A for
22797 type deduction." */
22800 /* try_one_overload doesn't provide an arg_expr, but
22801 functions are always lvalues. */
22805 /* [temp.deduct.call]
22807 If P is a cv-qualified type, the top level cv-qualifiers
22808 of P's type are ignored for type deduction. If P is a
22809 reference type, the type referred to by P is used for
22810 type deduction. */
22813 {
22816 }
22819 }
22821 /* Return true if computing a conversion from FROM to TO might induce template
22822 instantiation. Conversely, if this predicate returns false then computing
22823 the conversion definitely won't induce template instantiation. */
22825 static bool
22827 {
22834 {
22838 }
22840 /* If one of the types is a not-yet-instantiated class template
22841 specialization, then computing the conversion might instantiate
22842 it in order to inspect bases, conversion functions and/or
22843 converting constructors. */
22852 /* Converting from one pointer type to another, or between
22853 reference-related types, always yields a standard conversion. */
22857 /* Converting to a non-aggregate class type will consider its
22858 user-declared constructors, which might induce instantiation. */
22863 /* Similarly, converting from a class type will consider its conversion
22864 functions. */
22869 /* Otherwise, computing this conversion definitely won't induce
22870 template instantiation. */
22872 }
22874 /* Subroutine of fn_type_unification. PARM is a function parameter of a
22875 template which doesn't contain any deducible template parameters; check if
22876 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
22877 unify_one_argument. */
22879 static int
22883 {
22884 tree type;
22888 else
22896 {
22899 }
22901 {
22903 {
22904 /* This conversion was already computed earlier (when
22905 computing only non-instantiating conversions). */
22908 }
22917 /* Avoid recalculating this in add_function_candidate. */
22918 ok = (*conv_p
22920 else
22924 }
22928 else
22930 }
22934 /* Returns true iff the expression EXPR is one from which a template
22935 argument can be deduced. In other words, if it's an undecorated
22936 use of a template non-type parameter. */
22938 static bool
22940 {
22941 /* Strip implicit conversions and implicit INDIRECT_REFs. */
22947 }
22949 /* Returns true iff the array domain DOMAIN uses a template parameter in a
22950 deducible way; that is, if it has a max value of <PARM> - 1. */
22952 static bool
22954 {
22963 }
22965 /* Returns true iff the template arguments ARGS use a template parameter
22966 in a deducible way. */
22968 static bool
22970 {
22972 {
22976 else
22977 {
22984 else
22986 }
22989 }
22991 }
22993 /* Returns true iff TYPE contains any deducible references to template
22994 parameters, as per 14.8.2.5. */
22996 static bool
22998 {
23002 /* T
23003 cv-list T
23004 TT<T>
23005 TT<i>
23006 TT<> */
23011 /* T*
23012 T&
23013 T&& */
23017 /* T[integer-constant ]
23018 type [i] */
23023 /* T type ::*
23024 type T::*
23025 T T::*
23026 T (type ::*)()
23027 type (T::*)()
23028 type (type ::*)(T)
23029 type (T::*)(T)
23030 T (type ::*)(T)
23031 T (T::*)()
23032 T (T::*)(T) */
23035 || (uses_deducible_template_parms
23038 /* template-name <T> (where template-name refers to a class template)
23039 template-name <i> (where template-name refers to a class template) */
23046 /* type (T)
23047 T()
23048 T(T) */
23050 {
23064 }
23067 }
23069 /* Subroutine of type_unification_real and unify_pack_expansion to
23070 handle unification of a single P/A pair. Parameters are as
23071 for those functions. */
23073 static int
23077 {
23084 /* We can't deduce anything from this, but we might get all the
23085 template args from other function args. */
23088 /* Implicit conversions (Clause 4) will be performed on a function
23089 argument to convert it to the type of the corresponding function
23090 parameter if the parameter type contains no template-parameters that
23091 participate in template argument deduction. */
23094 /* For function parameters with no deducible template parameters,
23095 just return. We'll check non-dependent conversions later. */
23099 {
23101 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
23102 | UNIFY_ALLOW_MORE_CV_QUAL
23116 }
23118 /* We only do these transformations if this is the top-level
23119 parameter_type_list in a call or declaration matching; in other
23120 situations (nested function declarators, template argument lists) we
23121 won't be comparing a type to an expression, and we don't do any type
23122 adjustments. */
23124 {
23126 {
23129 {
23130 /* [temp.deduct.type] A template-argument can be
23131 deduced from a pointer to function or pointer
23132 to member function argument if the set of
23133 overloaded functions does not contain function
23134 templates and at most one of a set of
23135 overloaded functions provides a unique
23136 match. */
23140 /* If a unique match was not found, this is a
23141 non-deduced context, so we still succeed. */
23143 }
23149 }
23153 }
23154 else
23159 /* For deduction from an init-list we need the actual list. */
23163 }
23165 /* for_each_template_parm callback that always returns 0. */
23167 static int
23169 {
23171 }
23173 /* for_each_template_parm any_fn callback to handle deduction of a template
23174 type argument from the type of an array bound. */
23176 static int
23178 {
23186 {
23192 }
23194 /* Keep walking. */
23196 }
23198 /* Try to deduce any not-yet-deduced template type arguments from the type of
23199 an array bound. This is handled separately from unify because 14.8.2.5 says
23200 "The type of a type parameter is only deduced from an array bound if it is
23201 not otherwise deduced." */
23203 static void
23205 {
23210 }
23212 /* Most parms like fn_type_unification.
23214 If SUBR is 1, we're being called recursively (to unify the
23215 arguments of a function or method parameter of a function
23216 template).
23218 CHECKS is a pointer to a vector of access checks encountered while
23219 substituting default template arguments. */
23221 static int
23223 tree full_targs,
23224 tree xparms,
23228 unification_kind_t strict,
23231 {
23236 tree parms;
23247 /* Reset the number of non-defaulted template arguments contained
23248 in TARGS. */
23251 again:
23256 /* Only fn_type_unification cares about terminal void. */
23263 {
23268 /* For a function parameter pack that occurs at the end of the
23269 parameter-declaration-list, the type A of each remaining
23270 argument of the call is compared with the type P of the
23271 declarator-id of the function parameter pack. */
23277 /* For a function parameter pack that does not occur at the
23278 end of the parameter-declaration-list, the type of the
23279 parameter pack is a non-deduced context. */
23286 explain_p))
23288 }
23293 {
23294 /* Unify the remaining arguments with the pack expansion type. */
23295 tree argvec;
23298 /* Allocate a TREE_VEC and copy in all of the arguments */
23303 /* Copy the parameter into parmvec. */
23309 /* Advance to the end of the list of parameters. */
23311 }
23313 /* Fail if we've reached the end of the parm list, and more args
23314 are present, and the parm list isn't variadic. */
23317 /* Fail if parms are left and they don't have default values and
23318 they aren't all deduced as empty packs (c++/57397). This is
23319 consistent with sufficient_parms_p. */
23322 {
23326 do
23327 {
23330 count++;
23332 }
23336 type_pack_p);
23337 }
23340 {
23341 tsubst_flags_t complain = (explain_p
23342 ? tf_warning_or_error
23347 {
23351 /* Clear the "incomplete" flags on all argument packs now so that
23352 substituting them into later default arguments works. */
23354 {
23357 }
23365 {
23370 }
23372 /* If this is an undeduced nontype parameter that depends on
23373 a type parameter, try another pass; its type may have been
23374 deduced from a later argument than the one from which
23375 this parameter can be deduced. */
23380 {
23383 }
23385 /* Core issue #226 (C++0x) [temp.deduct]:
23387 If a template argument has not been deduced, its
23388 default template argument, if any, is used.
23390 When we are in C++98 mode, TREE_PURPOSE will either
23391 be NULL_TREE or ERROR_MARK_NODE, so we do not need
23392 to explicitly check cxx_dialect here. */
23394 /* OK, there is a default argument. Wait until after the
23395 conversion check to do substitution. */
23398 /* If the type parameter is a parameter pack, then it will
23399 be deduced to an empty parameter pack. */
23401 {
23402 tree arg;
23405 {
23408 }
23409 else
23416 }
23419 }
23421 /* During partial ordering, we deduce dependent template args. */
23424 /* Now substitute into the default template arguments. */
23426 {
23431 {
23435 }
23450 {
23451 /* The type of this non-type parameter depends on undeduced
23452 parameters. Don't try to use its default argument yet,
23453 since we might deduce an argument for it on the next pass,
23454 but do check whether the arguments we already have cause
23455 substitution failure, so that that happens before we try
23456 later default arguments (78489). */
23459 NULL_TREE);
23463 else
23465 }
23466 else
23467 {
23468 /* Even if the call is happening in template context, getting
23469 here means it's non-dependent, and a default argument is
23470 considered a separate definition under [temp.decls], so we can
23471 do this substitution without processing_template_decl. This
23472 is important if the default argument contains something that
23473 might be instantiation-dependent like access (87480). */
23477 {
23478 /* First instatiate in template context, in case we still
23479 depend on undeduced template parameters. */
23482 NULL_TREE);
23486 /* We replaced all the tparms, substitute again out of
23487 template context. */
23489 }
23492 NULL_TREE);
23501 }
23510 {
23512 /* The position of the first default template argument,
23513 is also the number of non-defaulted arguments in TARGS.
23514 Record that. */
23517 }
23518 }
23522 }
23528 }
23530 /* Subroutine of type_unification_real. Args are like the variables
23531 at the call site. ARG is an overloaded function (or template-id);
23532 we try deducing template args from each of the overloads, and if
23533 only one succeeds, we go with that. Modifies TARGS and returns
23534 true on success. */
23536 static bool
23538 tree targs,
23539 tree parm,
23540 tree arg,
23541 unification_kind_t strict,
23544 {
23551 {
23554 }
23555 else
23559 /* Handle `&x' where `x' is some static or non-static member
23560 function name. */
23566 /* Strip baselink information. */
23571 {
23572 /* If we got some explicit template args, we need to plug them into
23573 the affected templates before we try to unify, in case the
23574 explicit args will completely resolve the templates in question. */
23581 {
23592 {
23597 {
23598 /* Instantiate the function to deduce its return type. */
23602 }
23611 {
23614 }
23615 }
23618 }
23619 /* If no templates (or more than one) are fully resolved by the
23620 explicit arguments, this template-id is a non-deduced context; it
23621 could still be OK if we deduce all template arguments for the
23622 enclosing call through other arguments. */
23625 }
23627 /* If ARG is, for example, "(0, &f)" then its type will be unknown
23628 -- but the deduction does not succeed because the expression is
23629 not just the function on its own. */
23631 else
23633 {
23638 {
23641 }
23642 }
23644 /* [temp.deduct.type] A template-argument can be deduced from a pointer
23645 to function or pointer to member function argument if the set of
23646 overloaded functions does not contain function templates and at most
23647 one of a set of overloaded functions provides a unique match.
23649 So if we found multiple possibilities, we return success but don't
23650 deduce anything. */
23653 {
23657 {
23662 /* Don't forget explicit template arguments in a pack. */
23666 }
23667 }
23672 }
23674 /* Core DR 115: In contexts where deduction is done and fails, or in
23675 contexts where deduction is not done, if a template argument list is
23676 specified and it, along with any default template arguments, identifies
23677 a single function template specialization, then the template-id is an
23678 lvalue for the function template specialization. */
23680 tree
23682 {
23695 {
23698 }
23700 {
23703 }
23705 {
23708 }
23711 {
23715 /* If we got some explicit template args, we need to plug them into
23716 the affected templates before we try to unify, in case the
23717 explicit args will completely resolve the templates in question. */
23725 {
23736 {
23739 {
23742 }
23745 {
23748 }
23749 }
23750 }
23752 {
23760 {
23761 tree base
23764 }
23768 }
23770 /* There were no good options and at least one bad one, so let the
23771 user know what the problem is. */
23773 }
23775 }
23777 /* As above, but error out if the expression remains overloaded. */
23779 tree
23781 {
23784 {
23788 }
23790 }
23792 /* Subroutine of resolve_overloaded_unification; does deduction for a single
23793 overload. Fills TARGS with any deduced arguments, or error_mark_node if
23794 different overloads deduce different arguments for a given parm.
23795 ADDR_P is true if the expression for which deduction is being
23796 performed was of the form "& fn" rather than simply "fn".
23798 Returns 1 on success. */
23800 static int
23802 tree orig_targs,
23803 tree targs,
23804 tree parm,
23805 tree arg,
23806 unification_kind_t strict,
23810 {
23812 tree tempargs;
23818 /* [temp.deduct.type] A template-argument can be deduced from a pointer
23819 to function or pointer to member function argument if the set of
23820 overloaded functions does not contain function templates and at most
23821 one of a set of overloaded functions provides a unique match.
23823 So if this is a template, just return success. */
23836 /* We don't copy orig_targs for this because if we have already deduced
23837 some template args from previous args, unify would complain when we
23838 try to deduce a template parameter for the same argument, even though
23839 there isn't really a conflict. */
23846 /* First make sure we didn't deduce anything that conflicts with
23847 explicitly specified args. */
23849 {
23856 /* Since we're unifying against ourselves, we will fill in
23857 template args used in the function parm list with our own
23858 template parms. Discard them. */
23861 {
23862 /* Check that the argument at each index of the deduced argument pack
23863 is equivalent to the corresponding explicitly specified argument.
23864 We may have deduced more arguments than were explicitly specified,
23865 and that's OK. */
23867 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
23868 that's wrong if we deduce the same argument pack from multiple
23869 function arguments: it's only incomplete the first time. */
23882 }
23885 }
23888 {
23893 }
23896 }
23898 /* PARM is a template class (perhaps with unbound template
23899 parameters). ARG is a fully instantiated type. If ARG can be
23900 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
23901 TARGS are as for unify. */
23903 static tree
23906 {
23914 /* We need to make a new template argument vector for the call to
23915 unify. If we used TARGS, we'd clutter it up with the result of
23916 the attempted unification, even if this class didn't work out.
23917 We also don't want to commit ourselves to all the unifications
23918 we've already done, since unification is supposed to be done on
23919 an argument-by-argument basis. In other words, consider the
23920 following pathological case:
23922 template <int I, int J, int K>
23923 struct S {};
23925 template <int I, int J>
23926 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
23928 template <int I, int J, int K>
23929 void f(S<I, J, K>, S<I, I, I>);
23931 void g() {
23932 S<0, 0, 0> s0;
23933 S<0, 1, 2> s2;
23935 f(s0, s2);
23936 }
23938 Now, by the time we consider the unification involving `s2', we
23939 already know that we must have `f<0, 0, 0>'. But, even though
23940 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
23941 because there are two ways to unify base classes of S<0, 1, 2>
23942 with S<I, I, I>. If we kept the already deduced knowledge, we
23943 would reject the possibility I=1. */
23951 else
23958 }
23960 /* Given a template type PARM and a class type ARG, find the unique
23961 base type in ARG that is an instance of PARM. We do not examine
23962 ARG itself; only its base-classes. If there is not exactly one
23963 appropriate base class, return NULL_TREE. PARM may be the type of
23964 a partial specialization, as well as a plain template type. Used
23965 by unify. */
23967 static enum template_base_result
23970 {
23972 tree binfo;
23978 {
23979 /* The type could not be completed. */
23982 }
23984 /* Walk in inheritance graph order. The search order is not
23985 important, and this avoids multiple walks of virtual bases. */
23987 {
23992 {
23993 /* If there is more than one satisfactory baseclass, then:
23995 [temp.deduct.call]
23997 If they yield more than one possible deduced A, the type
23998 deduction fails.
24000 applies. */
24002 {
24003 /* [temp.deduct.call]/4.3: If there is a class C that is a
24004 (direct or indirect) base class of D and derived (directly or
24005 indirectly) from a class B and that would be a valid deduced
24006 A, the deduced A cannot be B or pointer to B, respectively. */
24008 /* Ignore r. */
24012 else
24013 {
24016 }
24017 }
24020 }
24021 }
24025 }
24027 /* Returns the level of DECL, which declares a template parameter. */
24029 static int
24031 {
24033 {
24043 }
24045 }
24047 /* Decide whether ARG can be unified with PARM, considering only the
24048 cv-qualifiers of each type, given STRICT as documented for unify.
24049 Returns nonzero iff the unification is OK on that basis. */
24051 static int
24053 {
24059 {
24060 /* Although a CVR qualifier is ignored when being applied to a
24061 substituted template parameter ([8.3.2]/1 for example), that
24062 does not allow us to unify "const T" with "int&" because both
24063 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
24064 It is ok when we're allowing additional CV qualifiers
24065 at the outer level [14.8.2.1]/3,1st bullet. */
24074 }
24085 }
24087 /* Determines the LEVEL and INDEX for the template parameter PARM. */
24088 void
24090 {
24094 {
24097 }
24098 else
24099 {
24102 }
24103 }
24105 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
24106 do { \
24107 if (unify (TP, TA, P, A, S, EP)) \
24108 return 1; \
24109 } while (0)
24111 /* Unifies the remaining arguments in PACKED_ARGS with the pack
24112 expansion at the end of PACKED_PARMS. Returns 0 if the type
24113 deduction succeeds, 1 otherwise. STRICT is the same as in
24114 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
24115 function call argument list. We'll need to adjust the arguments to make them
24116 types. SUBR tells us if this is from a recursive call to
24117 type_unification_real, or for comparing two template argument
24118 lists. */
24120 static int
24124 {
24125 tree parm
24131 /* Add in any args remembered from an earlier partial instantiation. */
24139 /* Determine the parameter packs we will be deducing from the
24140 pattern, and record their current deductions. */
24143 {
24147 /* Only template parameter packs can be deduced, not e.g. function
24148 parameter packs or __bases or __integer_pack. */
24152 /* Determine the index and level of this parameter pack. */
24157 /* Keep track of the parameter packs and their corresponding
24158 argument packs. */
24161 }
24163 /* Loop through all of the arguments that have not yet been
24164 unified and unify each with the pattern. */
24166 {
24167 tree parm;
24171 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
24172 or the element of its argument pack at the current index if
24173 this argument was explicitly specified. */
24175 {
24184 {
24187 }
24189 }
24191 /* If we had explicit template arguments, substitute them into the
24192 pattern before deduction. */
24194 {
24195 /* Some arguments might still be unspecified or dependent. */
24203 NULL_TREE);
24208 }
24209 else
24212 /* Unify the pattern with the current argument. */
24214 explain_p))
24217 /* For each parameter pack, collect the deduced value. */
24219 {
24225 }
24226 }
24228 /* Verify that the results of unification with the parameter packs
24229 produce results consistent with what we've seen before, and make
24230 the deduced argument packs available. */
24232 {
24239 /* By default keep the original deduced argument pack.
24240 If necessary, more specific code is going to update the
24241 resulting deduced argument later down in this function. */
24245 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
24246 actually deduce anything. */
24254 {
24255 /* If we had fewer function args than explicit template args,
24256 just use the explicits. */
24261 }
24264 {
24265 tree result;
24266 /* Build the deduced *_ARGUMENT_PACK. */
24268 {
24271 }
24272 else
24277 /* Note the deduced argument packs for this parameter
24278 pack. */
24280 }
24284 {
24285 /* We only had the explicitly-provided arguments before, but
24286 now we have a complete set of arguments. */
24292 }
24293 else
24294 {
24298 /* During template argument deduction for the aggregate deduction
24299 candidate, the number of elements in a trailing parameter pack
24300 is only deduced from the number of remaining function
24301 arguments if it is not otherwise deduced. */
24304 /* FIXME This isn't set properly for partial instantiations. */
24310 /* Inconsistent unification of this parameter pack. */
24312 bad_old_arg,
24313 bad_new_arg);
24314 }
24315 }
24318 }
24320 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
24321 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
24322 parameters and return value are as for unify. */
24324 static int
24328 {
24329 tree parm_max;
24330 tree arg_max;
24334 /* Our representation of array types uses "N - 1" as the
24335 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
24336 not an integer constant. We cannot unify arbitrarily
24337 complex expressions, so we eliminate the MINUS_EXPRs
24338 here. */
24342 {
24345 }
24349 {
24350 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
24351 trying to unify the type of a variable with the type
24352 of a template parameter. For example:
24354 template <unsigned int N>
24355 void f (char (&) [N]);
24356 int g();
24357 void h(int i) {
24358 char a[g(i)];
24359 f(a);
24360 }
24362 Here, the type of the ARG will be "int [g(i)]", and
24363 may be a SAVE_EXPR, etc. */
24367 }
24369 /* If only one of the bounds used a MINUS_EXPR, compensate
24370 by adding one to the other bound. */
24373 integer_type_node,
24374 parm_max,
24375 integer_one_node);
24378 integer_type_node,
24379 arg_max,
24380 integer_one_node);
24384 }
24386 /* Returns whether T, a P or A in unify, is a type, template or expression. */
24390 static pa_kind_t
24392 {
24401 else
24403 }
24405 /* Deduce the value of template parameters. TPARMS is the (innermost)
24406 set of template parameters to a template. TARGS is the bindings
24407 for those template parameters, as determined thus far; TARGS may
24408 include template arguments for outer levels of template parameters
24409 as well. PARM is a parameter to a template function, or a
24410 subcomponent of that parameter; ARG is the corresponding argument.
24411 This function attempts to match PARM with ARG in a manner
24412 consistent with the existing assignments in TARGS. If more values
24413 are deduced, then TARGS is updated.
24415 Returns 0 if the type deduction succeeds, 1 otherwise. The
24416 parameter STRICT is a bitwise or of the following flags:
24418 UNIFY_ALLOW_NONE:
24419 Require an exact match between PARM and ARG.
24420 UNIFY_ALLOW_MORE_CV_QUAL:
24421 Allow the deduced ARG to be more cv-qualified (by qualification
24422 conversion) than ARG.
24423 UNIFY_ALLOW_LESS_CV_QUAL:
24424 Allow the deduced ARG to be less cv-qualified than ARG.
24425 UNIFY_ALLOW_DERIVED:
24426 Allow the deduced ARG to be a template base class of ARG,
24427 or a pointer to a template base class of the type pointed to by
24428 ARG.
24429 UNIFY_ALLOW_INTEGER:
24430 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
24431 case for more information.
24432 UNIFY_ALLOW_OUTER_LEVEL:
24433 This is the outermost level of a deduction. Used to determine validity
24434 of qualification conversions. A valid qualification conversion must
24435 have const qualified pointers leading up to the inner type which
24436 requires additional CV quals, except at the outer level, where const
24437 is not required [conv.qual]. It would be normal to set this flag in
24438 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
24439 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
24440 This is the outermost level of a deduction, and PARM can be more CV
24441 qualified at this point.
24442 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
24443 This is the outermost level of a deduction, and PARM can be less CV
24444 qualified at this point. */
24446 static int
24449 {
24451 tree targ;
24452 tree tparm;
24454 tsubst_flags_t complain = (explain_p
24455 ? tf_warning_or_error
24458 /* I don't think this will do the right thing with respect to types.
24459 But the only case I've seen it in so far has been array bounds, where
24460 signedness is the only information lost, and I think that will be
24461 okay. VIEW_CONVERT_EXPR can appear with class NTTP, thanks to
24462 finish_id_expression_1, and are also OK. */
24470 /* We can't deduce anything from this, but we might get all the
24471 template args from other function args. */
24477 /* If PARM uses template parameters, then we can't bail out here,
24478 even if ARG == PARM, since we won't record unifications for the
24479 template parameters. We might need them if we're trying to
24480 figure out which of two things is more specialized. */
24485 /* Handle init lists early, so the rest of the function can assume
24486 we're dealing with a type. */
24488 {
24489 tree elttype;
24494 /* We can only deduce from an initializer list argument if the
24495 parameter is std::initializer_list or an array; otherwise this
24496 is a non-deduced context. */
24501 else
24502 {
24504 /* Deduction is defined in terms of a single type, so just punt
24505 on the (bizarre) std::initializer_list<T...>. */
24508 }
24513 /* If ELTTYPE has no deducible template parms, skip deduction from
24515 else
24517 {
24525 {
24529 /* It should only be possible to get here for a call. */
24531 elt_strict |= maybe_adjust_types_for_deduction
24534 }
24537 explain_p);
24538 }
24542 {
24543 /* Also deduce from the length of the initializer list. */
24550 }
24552 /* If the std::initializer_list<T> deduction worked, replace the
24553 deduced A with std::initializer_list<A>. */
24555 {
24560 }
24562 }
24564 /* If parm and arg aren't the same kind of thing (template, type, or
24565 expression), fail early. */
24569 /* Immediately reject some pairs that won't unify because of
24570 cv-qualification mismatches. */
24573 /* It is the elements of the array which hold the cv quals of an array
24574 type, and the elements might be template type parms. We'll check
24575 when we recurse. */
24577 /* We check the cv-qualifiers when unifying with template type
24578 parameters below. We want to allow ARG `const T' to unify with
24579 PARM `T' for example, when computing which of two templates
24580 is more specialized, for example. */
24589 /* PMFs recurse at the same level, so don't strip this yet. */
24597 {
24601 /* In a type which contains a nested-name-specifier, template
24602 argument values cannot be deduced for template parameters used
24603 within the nested-name-specifier. */
24615 /* The PARM is not one we're trying to unify. Just check
24616 to see if it matches ARG. */
24617 {
24622 else
24624 }
24631 /* Check for mixed types and values. */
24639 {
24642 {
24643 /* First try to match ARG directly. */
24645 explain_p);
24647 {
24648 /* Otherwise, look for a suitable base of ARG, as below. */
24655 }
24656 }
24657 /* ARG must be constructed from a template class or a template
24658 template parameter. */
24663 /* Deduce arguments T, i from TT<T> or TT<i>. */
24669 /* If the template is a template template parameter, use the
24670 TEMPLATE_TEMPLATE_PARM for matching. */
24673 /* Fall through to deduce template name. */
24674 }
24678 {
24679 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
24681 /* Simple cases: Value already set, does match or doesn't. */
24686 }
24687 else
24688 {
24689 /* If PARM is `const T' and ARG is only `int', we don't have
24690 a match unless we are allowing additional qualification.
24691 If ARG is `const int' and PARM is just `T' that's OK;
24692 that binds `const int' to `T'. */
24697 /* Consider the case where ARG is `const volatile int' and
24698 PARM is `const T'. Then, T should be `volatile int'. */
24699 arg = cp_build_qualified_type
24704 /* Simple cases: Value already set, does match or doesn't. */
24710 /* Make sure that ARG is not a variable-sized array. (Note
24711 that were talking about variable-sized arrays (like
24712 `int[n]'), rather than arrays of unknown size (like
24713 `int[]').) We'll get very confused by such a type since
24714 the bound of the array is not constant, and therefore
24715 not mangleable. Besides, such types are not allowed in
24716 ISO C++, so we can do as we please here. We do allow
24717 them for 'auto' deduction, since that isn't ABI-exposed. */
24721 /* Strip typedefs as in convert_template_argument. */
24723 }
24725 /* If ARG is a parameter pack or an expansion, we cannot unify
24726 against it unless PARM is also a parameter pack. */
24731 /* If the argument deduction results is a METHOD_TYPE,
24732 then there is a problem.
24733 METHOD_TYPE doesn't map to any real C++ type the result of
24734 the deduction cannot be of that type. */
24748 {
24749 /* The PARM is not one we're trying to unify. Just check
24750 to see if it matches ARG. */
24756 }
24762 {
24766 /* We're deducing from an array bound, the type doesn't matter.
24767 This conversion should match the one below. */
24773 }
24775 /* [temp.deduct.type] If, in the declaration of a function template
24776 with a non-type template-parameter, the non-type
24777 template-parameter is used in an expression in the function
24778 parameter-list and, if the corresponding template-argument is
24779 deduced, the template-argument type shall match the type of the
24780 template-parameter exactly, except that a template-argument
24781 deduced from an array bound may be of any integral type.
24782 The non-type parameter might use already deduced type parameters. */
24785 /* We don't have enough levels of args to do any substitution. This
24787 else
24788 {
24794 {
24797 LOOKUP_NORMAL,
24801 }
24802 }
24806 /* Template-parameter dependent expression. Just accept it for now.
24807 It will later be processed in convert_template_argument. */
24808 ;
24812 /* OK. Ignore top-level quals here because a class-type template
24816 /* Convert the ARG to the type of PARM; the deduced non-type
24817 template argument must exactly match the types of the
24818 corresponding parameter. This conversion should match the
24819 one above. */
24822 {
24823 /* We haven't deduced the type of this parameter yet. */
24825 /* We deduce from array bounds in try_array_deduction. */
24828 {
24829 /* Deduce it from the non-type argument. As above, ignore
24830 top-level quals here too. */
24835 /* Now check whether the type of this parameter is still
24836 dependent, and give up if so. */
24842 }
24843 else
24844 /* Try again later. */
24846 }
24847 else
24850 /* If ARG is a parameter pack or an expansion, we cannot unify
24851 against it unless PARM is also a parameter pack. */
24856 {
24859 }
24864 {
24865 /* A pointer-to-member constant can be unified only with
24866 another constant. */
24870 /* Just unify the class member. It would be useless (and possibly
24871 wrong, depending on the strict flags) to unify also
24872 PTRMEM_CST_CLASS, because we want to be sure that both parm and
24873 arg refer to the same variable, even if through different
24874 classes. For instance:
24876 struct A { int x; };
24877 struct B : A { };
24879 Unification of &A::x and &B::x must succeed. */
24882 }
24885 {
24889 /* [temp.deduct.call]
24891 A can be another pointer or pointer to member type that can
24892 be converted to the deduced A via a qualification
24893 conversion (_conv.qual_).
24895 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
24896 This will allow for additional cv-qualification of the
24897 pointed-to types if appropriate. */
24900 /* The derived-to-base conversion only persists through one
24901 level of pointers. */
24906 }
24939 /* We have already checked cv-qualification at the top of the
24940 function. */
24944 /* As far as unification is concerned, this wins. Later checks
24945 will invalidate it if necessary. */
24948 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
24949 /* Type INTEGER_CST can come from ordinary constant template args. */
24964 {
24974 /* Check for pack expansions in the parameters. */
24976 {
24978 {
24980 /* We can unify against something with a trailing
24981 parameter pack. */
24983 else
24984 /* [temp.deduct.type]/9: If the template argument list of
24985 P contains a pack expansion that is not the last
24986 template argument, the entire template argument list
24987 is a non-deduced context. */
24989 }
24990 }
24992 /* If we don't have enough arguments to satisfy the parameters
24993 (not counting the pack expression at the end), or we have
24994 too many arguments for a parameter list that doesn't end in
24995 a pack expression, we can't unify. */
25001 /* Unify all of the parameters that precede the (optional)
25002 pack expression. */
25004 {
25009 }
25012 DEDUCE_EXACT,
25015 }
25023 {
25031 }
25036 {
25040 {
25041 /* First, we try to unify the PARM and ARG directly. */
25046 {
25047 /* Fallback to the special case allowed in
25048 [temp.deduct.call]:
25050 If P is a class, and P has the form
25051 template-id, then A can be a derived class of
25052 the deduced A. Likewise, if P is a pointer to
25053 a class of the form template-id, A can be a
25054 pointer to a derived class pointed to by the
25055 deduced A. */
25061 {
25062 /* Don't give the derived diagnostic if we're
25063 already dealing with the same template. */
25064 bool same_template
25070 }
25071 }
25072 }
25076 /* Perhaps PARM is something like S<U> and ARG is S<int>.
25077 Then, we should unify `int' and `U'. */
25079 else
25080 /* There's no chance of unification succeeding. */
25088 else
25090 }
25097 {
25100 tree a;
25106 /* CV qualifications for methods can never be deduced, they must
25107 match exactly. We need to check them explicitly here,
25108 because type_unification_real treats them as any other
25109 cv-qualified parameter. */
25111 && (!check_cv_quals_for_unify
25139 {
25149 else
25150 {
25153 /* Here "less cv-qual" means the deduced arg (i.e. parm) has
25154 /more/ noexcept, since function pointer conversions are the
25155 reverse of qualification conversions. */
25160 else
25162 }
25163 }
25165 {
25166 /* As for noexcept. */
25173 else
25175 }
25178 }
25181 /* Unify a pointer to member with a pointer to member function, which
25182 deduces the type of the member as a function type. */
25184 {
25185 /* Check top-level cv qualifiers */
25193 /* Determine the type of the function we are unifying against. */
25197 }
25208 /* CONST_DECL should already have been folded to its DECL_INITIAL. */
25214 /* Matched cases are handled by the ARG == PARM test above. */
25218 /* We might get a variable as a non-type template argument in parm if the
25219 corresponding parameter is type-dependent. Make any necessary
25220 adjustments based on whether arg is a reference. */
25224 {
25229 }
25230 /* Now use the normal expression code to check whether they match. */
25241 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
25242 or TRAIT_TYPE nodes. */
25246 /* Unification fails if we hit an error node. */
25251 {
25261 }
25262 /* FALLTHRU */
25265 /* An unresolved overload is a nondeduced context. */
25271 expr:
25272 /* We must be looking at an expression. This can happen with
25273 something like:
25275 template <int I>
25276 void foo(S<I>, S<I + 2>);
25278 or
25280 template<typename T>
25281 void foo(A<T, T{}>);
25283 This is a "non-deduced context":
25285 [deduct.type]
25287 The non-deduced contexts are:
25289 --A non-type template argument or an array bound in which
25290 a subexpression references a template parameter.
25292 In these cases, we assume deduction succeeded, but don't
25293 actually infer any unifications. */
25298 else
25300 }
25301 }
25302 #undef RECUR_AND_CHECK_FAILURE
25303 \f
25304 /* Note that DECL can be defined in this translation unit, if
25305 required. */
25307 static void
25309 {
25310 tree clone;
25314 }
25316 /* Called if RESULT is explicitly instantiated, or is a member of an
25317 explicitly instantiated class. */
25319 void
25321 {
25324 /* If this entity has already been written out, it's too late to
25325 make any modifications. */
25329 /* consteval functions are never emitted. */
25334 /* For anonymous namespace we don't need to do anything. */
25336 {
25339 }
25342 /* The TREE_PUBLIC flag for function declarations will have been
25343 set correctly by tsubst. */
25347 {
25350 }
25351 else
25352 {
25355 /* Always make artificials weak. */
25358 /* For WIN32 we also want to put explicit instantiations in
25359 linkonce sections. */
25364 /* If the function has already been instantiated, clear DECL_EXTERNAL,
25365 since start_preparsed_function wouldn't have if we had an earlier
25366 extern explicit instantiation. */
25368 }
25370 /* If EXTERN_P, then this function will not be emitted -- unless
25371 followed by an explicit instantiation, at which point its linkage
25372 will be adjusted. If !EXTERN_P, then this function will be
25373 emitted here. In neither circumstance do we want
25374 import_export_decl to adjust the linkage. */
25376 }
25378 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
25379 important template arguments. If any are missing, we check whether
25380 they're important by using error_mark_node for substituting into any
25381 args that were used for partial ordering (the ones between ARGS and END)
25382 and seeing if it bubbles up. */
25384 static bool
25386 {
25390 {
25393 }
25395 {
25399 }
25401 }
25403 /* Given two function templates PAT1 and PAT2, return:
25405 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
25406 -1 if PAT2 is more specialized than PAT1.
25407 0 if neither is more specialized.
25409 LEN indicates the number of parameters we should consider
25410 (defaulted parameters should not be considered).
25412 The 1998 std underspecified function template partial ordering, and
25413 DR214 addresses the issue. We take pairs of arguments, one from
25414 each of the templates, and deduce them against each other. One of
25415 the templates will be more specialized if all the *other*
25416 template's arguments deduce against its arguments and at least one
25417 of its arguments *does* *not* deduce against the other template's
25418 corresponding argument. Deduction is done as for class templates.
25419 The arguments used in deduction have reference and top level cv
25420 qualifiers removed. Iff both arguments were originally reference
25421 types *and* deduction succeeds in both directions, an lvalue reference
25422 wins against an rvalue reference and otherwise the template
25423 with the more cv-qualified argument wins for that pairing (if
25424 neither is more cv-qualified, they both are equal). Unlike regular
25425 deduction, after all the arguments have been deduced in this way,
25426 we do *not* verify the deduced template argument values can be
25427 substituted into non-deduced contexts.
25429 The logic can be a bit confusing here, because we look at deduce1 and
25430 targs1 to see if pat2 is at least as specialized, and vice versa; if we
25431 can find template arguments for pat1 to make arg1 look like arg2, that
25432 means that arg2 is at least as specialized as arg1. */
25434 int
25436 {
25449 /* C++17 [temp.func.order]/3 (CWG532)
25451 If only one of the function templates M is a non-static member of some
25452 class A, M is considered to have a new first parameter inserted in its
25453 function parameter list. Given cv as the cv-qualifiers of M (if any), the
25454 new parameter is of type "rvalue reference to cv A" if the optional
25455 ref-qualifier of M is && or if M has no ref-qualifier and the first
25456 parameter of the other template has rvalue reference type. Otherwise, the
25457 new parameter is of type "lvalue reference to cv A". */
25460 {
25461 /* Note C++20 DR2445 extended the above to static member functions, but
25462 I think think the old G++ behavior of just skipping the object
25463 parameter when comparing to a static member function was better, so
25464 let's stick with that for now. This is CWG2834. --jason 2023-12 */
25466 {
25469 }
25472 }
25475 {
25476 /* Note DR2445 also (IMO wrongly) removed the "only one" above, which
25477 would break e.g. cpp1y/lambda-generic-variadic5.C. */
25478 len--;
25481 }
25484 {
25485 /* The other is a non-member or explicit object member function;
25486 rewrite the implicit object parameter to a reference. */
25495 {
25501 }
25504 }
25506 /* If only one is a conversion operator, they are unordered. */
25510 /* Consider the return type for a conversion function */
25512 {
25515 len++;
25516 }
25518 processing_template_decl++;
25524 /* Stop when an ellipsis is seen. */
25526 {
25537 {
25538 /* When both arguments are pack expansions, we need only
25539 unify the patterns themselves. */
25543 /* This is the last comparison we need to do. */
25545 }
25548 {
25552 }
25555 {
25559 }
25565 {
25571 /* Setup the parameter vector, which contains only ARG1. */
25574 /* Setup the argument vector, which contains the remaining
25575 arguments. */
25584 /* We cannot deduce in the other direction, because ARG1 is
25585 a pack expansion but ARG2 is not. */
25587 }
25589 {
25595 /* Setup the parameter vector, which contains only ARG1. */
25598 /* Setup the argument vector, which contains the remaining
25599 arguments. */
25608 /* We cannot deduce in the other direction, because ARG2 is
25609 a pack expansion but ARG1 is not.*/
25611 }
25613 else
25614 {
25615 /* The normal case, where neither argument is a pack
25616 expansion. */
25623 }
25625 /* If we couldn't deduce arguments for tparms1 to make arg1 match
25626 arg2, then arg2 is not as specialized as arg1. */
25632 /* "If, for a given type, deduction succeeds in both directions
25633 (i.e., the types are identical after the transformations above)
25634 and both P and A were reference types (before being replaced with
25635 the type referred to above):
25636 - if the type from the argument template was an lvalue reference and
25637 the type from the parameter template was not, the argument type is
25638 considered to be more specialized than the other; otherwise,
25639 - if the type from the argument template is more cv-qualified
25640 than the type from the parameter template (as described above),
25641 the argument type is considered to be more specialized than the other;
25642 otherwise,
25643 - neither type is more specialized than the other." */
25646 {
25648 {
25651 else
25653 }
25655 {
25660 }
25661 }
25664 /* We've failed to deduce something in either direction.
25665 These must be unordered. */
25670 /* We have already processed all of the arguments in our
25671 handing of the pack expansion type. */
25676 }
25678 /* "In most cases, all template parameters must have values in order for
25679 deduction to succeed, but for partial ordering purposes a template
25680 parameter may remain without a value provided it is not used in the
25681 types being used for partial ordering."
25683 Thus, if we are missing any of the targs1 we need to substitute into
25684 origs1, then pat2 is not as specialized as pat1. This can happen when
25685 there is a nondeduced context. */
25691 processing_template_decl--;
25693 /* If both deductions succeed, the partial ordering selects the more
25694 constrained template. */
25695 /* P2113: If the corresponding template-parameters of the
25696 template-parameter-lists are not equivalent ([temp.over.link]) or if
25697 the function parameters that positionally correspond between the two
25698 templates are not of the same type, neither template is more
25699 specialized than the other. */
25704 {
25710 }
25712 /* All things being equal, if the next argument is a pack expansion
25713 for one function but not for the other, prefer the
25714 non-variadic function. FIXME this is bogus; see c++/41958. */
25718 {
25721 }
25727 else
25729 }
25731 /* Determine which of two partial specializations of TMPL is more
25732 specialized.
25734 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
25735 to the first partial specialization. The TREE_PURPOSE is the
25736 innermost set of template parameters for the partial
25737 specialization. PAT2 is similar, but for the second template.
25739 Return 1 if the first partial specialization is more specialized;
25740 -1 if the second is more specialized; 0 if neither is more
25741 specialized.
25743 See [temp.class.order] for information about determining which of
25744 two templates is more specialized. */
25746 static int
25748 {
25749 tree targs;
25758 /* Just like what happens for functions, if we are ordering between
25759 different template specializations, we may encounter dependent
25760 types in the arguments, and we need our dependency check functions
25761 to behave correctly. */
25765 {
25768 }
25772 {
25775 }
25778 /* If both deductions succeed, the partial ordering selects the more
25779 constrained template. */
25783 /* In the case of a tie where at least one of the templates
25784 has a parameter pack at the end, the template with the most
25785 non-packed parameters wins. */
25787 && any_deductions
25790 {
25796 /* We don't count the pack expansion at the end. */
25806 }
25809 }
25811 /* Return the template arguments that will produce the function signature
25812 DECL from the function template FN, with the explicit template
25813 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
25814 also match. Return NULL_TREE if no satisfactory arguments could be
25815 found. */
25817 static tree
25819 {
25823 tree decl_arg_types;
25826 tree arg;
25830 /* Never do unification on the 'this' parameter. */
25852 }
25854 /* Return the innermost template arguments that, when applied to a partial
25855 specialization SPEC_TMPL of TMPL, yield the ARGS.
25857 For example, suppose we have:
25859 template <class T, class U> struct S {};
25860 template <class T> struct S<T*, int> {};
25862 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
25863 partial specialization and the ARGS will be {double*, int}. The resulting
25864 vector will be {double}, indicating that `T' is bound to `double'. */
25866 static tree
25868 {
25870 tree spec_args
25873 tree deduced_args;
25874 tree innermost_deduced_args;
25878 {
25882 innermost_deduced_args);
25883 }
25884 else
25888 again:
25897 {
25899 {
25905 }
25907 }
25910 {
25913 }
25915 /* Verify that nondeduced template arguments agree with the type
25916 obtained from argument deduction.
25918 For example:
25920 struct A { typedef int X; };
25921 template <class T, class U> struct C {};
25922 template <class T> struct C<T, typename T::X> {};
25924 Then with the instantiation `C<A, int>', we can deduce that
25925 `T' is `A' but unify () does not check whether `typename T::X'
25926 is `int'. */
25937 /* We only need to check the innermost arguments; the other
25938 arguments will always agree. */
25943 /* Now that we have bindings for all of the template arguments,
25944 ensure that the arguments deduced for the template template
25945 parameters have compatible template parameter lists. See the use
25946 of template_template_parm_bindings_ok_p in fn_type_unification
25947 for more information. */
25952 }
25954 // Compare two function templates T1 and T2 by deducing bindings
25955 // from one against the other. If both deductions succeed, compare
25956 // constraints to see which is more constrained.
25957 static int
25959 {
25964 {
25967 }
25970 {
25973 }
25975 // If both deductions succeed, then one may be more constrained.
25980 }
25982 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
25983 Return the TREE_LIST node with the most specialized template, if
25984 any. If there is no most specialized template, the error_mark_node
25985 is returned.
25987 Note that this function does not look at, or modify, the
25988 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
25989 returned is one of the elements of INSTANTIATIONS, callers may
25990 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
25991 and retrieve it from the value returned. */
25993 tree
25995 {
26002 {
26008 {
26009 /* Equally specialized, move to next function. If there
26010 is no next function, nothing's most specialized. */
26015 }
26016 }
26019 /* Now verify that champ is better than everything earlier in the
26020 instantiation list. */
26023 {
26026 }
26027 }
26029 processing_template_decl--;
26035 }
26037 /* If DECL is a specialization of some template, return the most
26038 general such template. Otherwise, returns NULL_TREE.
26040 For example, given:
26042 template <class T> struct S { template <class U> void f(U); };
26044 if TMPL is `template <class U> void S<int>::f(U)' this will return
26045 the full template. This function will not trace past partial
26046 specializations, however. For example, given in addition:
26048 template <class T> struct S<T*> { template <class U> void f(U); };
26050 if TMPL is `template <class U> void S<int*>::f(U)' this will return
26051 `template <class T> template <class U> S<T*>::f(U)'. */
26053 tree
26055 {
26057 {
26060 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
26061 template friend, or a FIELD_DECL for a capture pack. */
26064 }
26069 /* Look for more and more general templates. */
26071 {
26072 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
26073 (See cp-tree.h for details.) */
26082 /* Stop if we run into an explicitly specialized class template. */
26089 }
26092 }
26094 /* Return the most specialized of the template partial specializations
26095 which can produce TARGET, a specialization of some class or variable
26096 template. The value returned is a TEMPLATE_INFO; the TI_TEMPLATE is a
26097 TEMPLATE_DECL node corresponding to the partial specialization, while
26098 the TI_ARGS is the set of template arguments that must be substituted
26099 into the template pattern in order to generate TARGET. The result is
26100 cached in the TI_PARTIAL_INFO of the corresponding TEMPLATE_INFO unless
26101 RECHECKING is true.
26103 If the choice of partial specialization is ambiguous, a diagnostic
26104 is issued, and the error_mark_node is returned. If there are no
26105 partial specializations matching TARGET, then NULL_TREE is
26106 returned, indicating that the primary template should be used. */
26108 tree
26111 {
26115 {
26120 }
26122 {
26126 }
26128 {
26133 }
26134 else
26141 && tinfo
26148 /* There are no partial specializations of this template. */
26154 /* For determining which partial specialization to use, only the
26155 innermost args are interesting. */
26158 {
26161 }
26163 /* The caller hasn't called push_to_top_level yet, but we need
26164 get_partial_spec_bindings to be done in non-template context so that we'll
26165 fully resolve everything. */
26166 processing_template_decl_sentinel ptds;
26170 {
26173 tree spec_tmpl;
26175 {
26176 /* Substitute in the template args from the enclosing class. */
26182 }
26183 else
26188 {
26192 /* Keep the candidate only if its constraints are satisfied. */
26195 }
26196 }
26204 {
26207 ;
26208 else
26209 {
26211 {
26214 {
26217 }
26218 }
26220 }
26221 }
26225 {
26228 {
26231 }
26232 }
26235 {
26242 else
26246 {
26251 }
26254 }
26260 }
26262 /* Explicitly instantiate DECL. */
26264 void
26266 {
26271 /* An error occurred, for which grokdeclarator has already issued
26272 an appropriate message. */
26275 {
26278 }
26280 {
26283 else
26286 }
26292 {
26293 /* There is an asymmetry here in the way VAR_DECLs and
26294 FUNCTION_DECLs are handled by grokdeclarator. In the case of
26295 the latter, the DECL we get back will be marked as a
26296 template instantiation, and the appropriate
26297 DECL_TEMPLATE_INFO will be set up. This does not happen for
26298 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
26299 should handle VAR_DECLs as it currently handles
26300 FUNCTION_DECLs. */
26302 {
26305 }
26308 {
26311 }
26313 {
26318 }
26319 }
26321 {
26324 }
26325 else
26328 /* Check for various error cases. Note that if the explicit
26329 instantiation is valid the RESULT will currently be marked as an
26330 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
26331 until we get here. */
26334 {
26335 /* DR 259 [temp.spec].
26337 Both an explicit instantiation and a declaration of an explicit
26338 specialization shall not appear in a program unless the explicit
26339 instantiation follows a declaration of the explicit specialization.
26341 For a given set of template parameters, if an explicit
26342 instantiation of a template appears after a declaration of an
26343 explicit specialization for that template, the explicit
26344 instantiation has no effect. */
26346 }
26348 {
26349 /* [temp.spec]
26351 No program shall explicitly instantiate any template more
26352 than once.
26354 We check DECL_NOT_REALLY_EXTERN so as not to complain when
26355 the first instantiation was `extern' and the second is not,
26356 and EXTERN_P for the opposite case. */
26359 /* If an "extern" explicit instantiation follows an ordinary
26360 explicit instantiation, the template is instantiated. */
26363 }
26365 {
26368 }
26370 {
26373 }
26376 ;
26378 {
26381 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
26384 }
26385 else
26393 }
26395 static void
26397 {
26403 {
26406 }
26407 }
26409 /* Perform an explicit instantiation of template class T. STORAGE, if
26410 non-null, is the RID for extern, inline or static. COMPLAIN is
26411 nonzero if this is called from the parser, zero if called recursively,
26412 since the standard is unclear (as detailed below). */
26414 void
26416 {
26418 {
26422 else
26425 }
26430 {
26433 t);
26435 }
26437 /* At most one of these will be true. */
26443 {
26445 {
26448 "ISO C++ 1998 forbids the use of %<extern%> on "
26450 }
26451 else
26453 "ISO C++ forbids the use of %qE"
26462 else
26464 storage);
26465 }
26468 /* DR 259 [temp.spec].
26470 Both an explicit instantiation and a declaration of an explicit
26471 specialization shall not appear in a program unless the
26472 explicit instantiation follows a declaration of the explicit
26473 specialization.
26475 For a given set of template parameters, if an explicit
26476 instantiation of a template appears after a declaration of an
26477 explicit specialization for that template, the explicit
26478 instantiation has no effect. */
26482 {
26483 /* We've already instantiated the template. */
26485 /* [temp.spec]
26487 No program shall explicitly instantiate any template more
26488 than once.
26490 If EXTERN_P then this is ok. */
26496 }
26504 /* In contrast to implicit instantiation, where only the
26505 declarations, and not the definitions, of members are
26506 instantiated, we have here:
26508 [temp.explicit]
26510 An explicit instantiation that names a class template
26511 specialization is also an explicit instantiation of the same
26512 kind (declaration or definition) of each of its members (not
26513 including members inherited from base classes and members
26514 that are templates) that has not been previously explicitly
26515 specialized in the translation unit containing the explicit
26516 instantiation, provided that the associated constraints, if
26517 any, of that member are satisfied by the template arguments
26518 of the explicit instantiation. */
26522 && !static_p
26526 {
26531 }
26533 {
26539 }
26540 }
26542 /* Given a function DECL, which is a specialization of TMPL, modify
26543 DECL to be a re-instantiation of TMPL with the same template
26544 arguments. TMPL should be the template into which tsubst'ing
26545 should occur for DECL, not the most general template.
26547 One reason for doing this is a scenario like this:
26549 template <class T>
26550 void f(const T&, int i);
26552 void g() { f(3, 7); }
26554 template <class T>
26555 void f(const T& t, const int i) { }
26557 Note that when the template is first instantiated, with
26558 instantiate_template, the resulting DECL will have no name for the
26559 first parameter, and the wrong type for the second. So, when we go
26560 to instantiate the DECL, we regenerate it. */
26562 static void
26564 {
26565 /* The arguments used to instantiate DECL, from the most general
26566 template. */
26569 /* Make sure that we can see identifiers, and compute access correctly. */
26573 {
26574 tree specs;
26578 /* Don't bother with this for unique friends that can't be redeclared and
26579 might change type if regenerated (PR69836). */
26583 /* Use the source location of the definition. */
26591 /* Instantiate a dynamic exception-specification. noexcept will be
26592 handled below. */
26595 {
26601 specs);
26602 }
26604 /* Merge parameter declarations. */
26608 {
26615 }
26618 {
26619 /* If we're regenerating a specialization, the contracts will have
26620 been copied from the most general template. Replace those with
26621 the ones from the actual specialization. */
26624 {
26627 }
26630 }
26632 /* Merge additional specifiers from the CODE_PATTERN. */
26638 }
26640 {
26649 }
26650 else
26653 done:
26655 }
26657 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
26658 substituted to get DECL. */
26660 tree
26662 {
26665 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
26666 for the instantiation. This is not always the most general
26667 template. Consider, for example:
26669 template <class T>
26670 struct S { template <class U> void f();
26671 template <> void f<int>(); };
26673 and an instantiation of S<double>::f<int>. We want TD to be the
26674 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
26676 more general template. */
26678 /* We must also deal with friend templates. Given:
26680 template <class T> struct S {
26681 template <class U> friend void f() {};
26682 };
26684 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
26685 so far as the language is concerned, but that's still
26686 where we get the pattern for the instantiation from. On
26687 other hand, if the definition comes outside the class, say:
26689 template <class T> struct S {
26690 template <class U> friend void f();
26691 };
26692 template <class U> friend void f() {}
26694 we don't need to look any further. That's what the check for
26695 DECL_INITIAL is for. */
26699 {
26700 /* The present template, TD, should not be a definition. If it
26701 were a definition, we should be using it! Note that we
26702 cannot restructure the loop to just keep going until we find
26703 a template with a definition, since that might go too far if
26704 a specialization was declared, but not defined. */
26706 /* Fetch the more general template. */
26708 }
26711 }
26713 /* Returns true if we need to instantiate this template instance even if we
26714 know we aren't going to emit it. */
26716 bool
26718 {
26719 /* We always instantiate inline functions so that we can inline them. An
26720 explicit instantiation declaration prohibits implicit instantiation of
26721 non-inline functions. With high levels of optimization, we would
26722 normally inline non-inline functions -- but we're not allowed to do
26723 that for "extern template" functions. Therefore, we check
26724 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
26728 /* And we need to instantiate static data members so that
26729 their initializers are available in integral constant
26730 expressions. */
26733 }
26735 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
26736 instantiate it now, modifying TREE_TYPE (fn). Returns false on
26737 error, true otherwise. */
26739 bool
26741 {
26745 /* Don't instantiate a noexcept-specification from template context. */
26755 {
26757 /* We're in start_preparsed_function, keep going. */
26764 }
26775 /* For a member friend template we can get a TEMPLATE_DECL. Let's use
26776 its FUNCTION_DECL for the rest of this function -- push_access_scope
26777 doesn't accept TEMPLATE_DECLs. */
26779 {
26782 }
26785 {
26790 }
26792 {
26796 {
26799 /* This might have failed because of an unparsed DMI, so
26800 let's try again later. */
26802 }
26804 {
26805 /* If hash_set::add returns true, the element was already there. */
26810 fn);
26812 }
26814 {
26822 {
26823 /* If needed, set current_class_ptr for the benefit of
26824 tsubst_copy/PARM_DECL. */
26829 }
26831 /* If this function is represented by a TEMPLATE_DECL, then
26832 the deferred noexcept-specification might still contain
26833 dependent types, even after substitution. And we need the
26834 dependency check functions to work in build_noexcept_spec. */
26838 /* Do deferred instantiation of the noexcept-specifier. */
26843 /* Build up the noexcept-specification. */
26853 }
26854 else
26859 }
26862 {
26863 /* This failed with a hard error, so let's go with false. */
26866 }
26873 }
26875 /* We're starting to process the function INST, an instantiation of PATTERN;
26876 add their parameters to local_specializations. */
26878 void
26880 {
26884 {
26888 }
26890 {
26892 {
26895 }
26896 else
26897 {
26898 /* Register the (value) argument pack as a specialization of
26899 TMPL_PARM, then move on. */
26902 }
26903 }
26905 }
26907 /* Instantiate the body of D using PATTERN with ARGS. We have
26908 already determined PATTERN is the correct template to use.
26909 NESTED_P is true if this is a nested function, in which case
26910 PATTERN will be a FUNCTION_DECL not a TEMPLATE_DECL. */
26912 static void
26914 {
26919 {
26922 }
26923 else
26924 /* Only OMP reductions are nested. */
26936 {
26937 /* The variable might be a lambda's extra scope, and that
26938 lambda's visibility depends on D's. */
26941 }
26943 /* Mark D as instantiated so that recursive calls to
26944 instantiate_decl do not try to instantiate it again. */
26948 /* Regenerate the declaration in case the template has been modified
26949 by a subsequent redeclaration. */
26952 /* We already set the file and line above. Reset them now in case
26953 they changed as a result of calling regenerate_decl_from_template. */
26957 {
26958 /* Clear out DECL_RTL; whatever was there before may not be right
26959 since we've reset the type of the declaration. */
26963 /* The initializer is placed in DECL_INITIAL by
26964 regenerate_decl_from_template so we don't need to
26965 push/pop_access_scope again here. Pull it out so that
26966 cp_finish_decl can process it. */
26972 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
26973 initializer. That function will defer actual emission until
26974 we have a chance to determine linkage. */
26977 /* Enter the scope of D so that access-checking works correctly. */
26987 }
26991 {
26992 /* Set up the list of local specializations. */
26996 /* Set up context. */
26999 else
27000 {
27004 }
27006 /* Create substitution entries for the parameters. */
27009 /* Substitute into the body of the function. */
27013 else
27014 {
27018 /* Set the current input_location to the end of the function
27019 so that finish_function knows where we are. */
27020 input_location
27023 /* Remember if we saw an infinite loop in the template. */
27024 current_function_infinite_loop
27026 }
27028 /* Finish the function. */
27031 else
27032 {
27035 }
27039 }
27041 /* We're not deferring instantiation any more. */
27049 }
27051 /* Produce the definition of D, a _DECL generated from a template. If
27052 DEFER_OK is true, then we don't have to actually do the
27053 instantiation now; we just have to do it sometime. Normally it is
27054 an error if this is an explicit instantiation but D is undefined.
27055 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
27056 instantiated class template. */
27058 tree
27060 {
27062 tree gen_args;
27063 tree args;
27064 tree td;
27065 tree code_pattern;
27066 tree spec;
27067 tree gen_tmpl;
27073 /* This function should only be used to instantiate templates for
27074 functions and static member variables. */
27077 /* A concept is never instantiated. */
27083 /* We may have a pending instantiation of D itself. */
27086 /* Variables are never deferred; if instantiation is required, they
27087 are instantiated right away. That allows for better code in the
27088 case that an expression refers to the value of the variable --
27089 if the variable has a constant value the referring expression can
27090 take advantage of that fact. */
27094 /* Don't instantiate cloned functions. Instead, instantiate the
27095 functions they cloned. */
27104 /* D has already been instantiated or explicitly specialized, so
27105 there's nothing for us to do here.
27107 It might seem reasonable to check whether or not D is an explicit
27108 instantiation, and, if so, stop here. But when an explicit
27109 instantiation is deferred until the end of the compilation,
27110 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
27111 the instantiation. */
27114 /* Check to see whether we know that this template will be
27115 instantiated in some other file, as with "extern template"
27116 extension. */
27119 /* In general, we do not instantiate such templates. */
27126 /* We should already have the extra args. */
27130 /* And what's in the hash table should match D. */
27132 == d
27135 /* This needs to happen before any tsubsting. */
27141 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
27142 for the instantiation. */
27147 {
27148 /* Look up an explicit specialization, if any. */
27151 {
27154 }
27155 }
27159 /* We should never be trying to instantiate a member of a class
27160 template or partial specialization. */
27165 /* In the case of a friend template whose definition is provided
27166 outside the class, we may have too many arguments. Drop the
27167 ones we don't need. The same is true for specializations. */
27168 args = get_innermost_template_args
27172 {
27178 }
27179 else
27180 {
27184 else
27186 }
27188 /* We may be in the middle of deferred access check. Disable it now. */
27191 /* Unless an explicit instantiation directive has already determined
27192 the linkage of D, remember that a definition is available for
27193 this entity. */
27203 /* If D is a member of an explicitly instantiated class template,
27204 and no definition is available, treat it like an implicit
27205 instantiation. */
27208 {
27209 /* Leave linkage flags alone on instantiations with anonymous
27210 visibility. */
27212 {
27215 }
27217 }
27219 /* Defer all other templates, unless we have been explicitly
27220 forbidden from doing so. */
27222 template. */
27223 ! pattern_defined
27224 /* If it's OK to postpone instantiation, do so. */
27225 || defer_ok
27226 /* If this is a static data member that will be defined
27227 elsewhere, we don't want to instantiate the entire data
27228 member, but we do want to instantiate the initializer so that
27229 we can substitute that elsewhere. */
27231 /* Handle here a deleted function too, avoid generating
27232 its body (c++/61080). */
27234 {
27235 /* The definition of the static data member is now required so
27236 we must substitute the initializer. */
27240 {
27241 tree ns;
27242 tree init;
27251 args,
27253 /* If instantiating the initializer involved instantiating this
27254 again, don't call cp_finish_decl twice. */
27256 {
27257 /* Make sure the initializer is still constant, in case of
27258 circular dependency (template/instantiate6.C). */
27259 const_init
27263 }
27267 }
27269 /* We restore the source position here because it's used by
27270 add_pending_template. */
27276 /* [temp.explicit]
27278 The definition of a non-exported function template, a
27279 non-exported member function template, or a non-exported
27280 member function or static data member of a class template
27281 shall be present in every translation unit in which it is
27282 explicitly instantiated. */
27286 /* If we're in unevaluated context, we just wanted to get the
27287 constant value; this isn't an odr use, so don't queue
27288 a full instantiation. */
27290 /* ??? Historically, we have instantiated inline functions, even
27291 when marked as "extern template". */
27294 }
27295 else
27296 {
27301 }
27308 }
27310 /* Run through the list of templates that we wish we could
27311 instantiate, and instantiate any we can. RETRIES is the
27312 number of times we retry pending template instantiation. */
27314 void
27316 {
27320 /* Instantiating templates may trigger vtable generation. This in turn
27321 may require further template instantiations. We place a limit here
27322 to avoid infinite loop. */
27324 {
27328 "template instantiation depth exceeds maximum of %d"
27329 " instantiating %q+D, possibly from virtual table generation"
27333 /* Pretend that we defined it. */
27336 }
27338 do
27339 {
27344 {
27349 {
27351 {
27366 }
27369 }
27370 else
27371 {
27374 {
27375 instantiation
27381 }
27385 }
27388 {
27389 /* If INSTANTIATION has been instantiated, then we don't
27390 need to consider it again in the future. */
27395 }
27396 else
27397 {
27400 }
27403 }
27405 }
27409 }
27411 /* Substitute ARGVEC into T, which is a list of initializers for
27412 either base class or a non-static data member. The TREE_PURPOSEs
27413 are DECLs, and the TREE_VALUEs are the initializer values. Used by
27414 instantiate_decl. */
27416 static tree
27418 {
27423 {
27424 tree decl;
27425 tree init;
27431 {
27432 tree expr;
27433 tree arg;
27435 /* Expand the base class expansion type into separate base
27436 classes. */
27438 tf_warning_or_error,
27439 NULL_TREE);
27443 /* We'll be building separate TREE_LISTs of arguments for
27444 each base. */
27450 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
27451 expand each argument in the TREE_VALUE of t. */
27458 /* VOID_TYPE_NODE is used to indicate
27459 value-initialization. */
27460 {
27463 }
27464 else
27465 {
27466 /* Substitute parameter packs into each argument in the
27467 TREE_LIST. */
27470 {
27471 tree expanded_exprs;
27473 /* Expand the argument. */
27474 tree value;
27477 else
27478 {
27481 }
27482 expanded_exprs
27484 tf_warning_or_error,
27485 NULL_TREE);
27489 /* Prepend each of the expanded expressions to the
27490 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
27498 else
27503 }
27506 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
27507 since we built them backwards. */
27509 {
27512 }
27513 }
27514 }
27517 {
27519 {
27523 }
27524 else
27525 {
27526 tree tmp;
27530 else
27544 /* If we had an initializer but it instantiated to nothing,
27545 value-initialize the object. This will only occur when
27546 the initializer was a pack expansion where the parameter
27547 packs used in that expansion were of length zero. */
27550 }
27554 {
27556 decl);
27558 }
27559 /* Look for a target constructor. */
27563 {
27566 {
27570 }
27572 }
27575 {
27577 /* Carry over the dummy TREE_TYPE node containing the source
27578 location. */
27582 }
27583 }
27584 }
27586 }
27588 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
27589 is the instantiation (which should have been created with
27590 start_enum) and ARGS are the template arguments to use. */
27592 static void
27594 {
27595 tree e;
27601 {
27602 tree value;
27605 /* Note that in a template enum, the TREE_VALUE is the
27606 CONST_DECL, not the corresponding INTEGER_CST. */
27610 /* Give this enumeration constant the correct access. */
27613 /* Actually build the enumerator itself. Here we're assuming that
27614 enumerators can't have dependent attributes. */
27618 /* Attribute deprecated without an argument isn't sticky: it'll
27619 melt into a tree flag, so we need to propagate the flag here,
27620 since we just created a new enumerator. */
27623 }
27635 }
27637 /* DECL is a FUNCTION_DECL that is a template specialization. Return
27638 its type -- but without substituting the innermost set of template
27639 arguments. So, innermost set of template parameters will appear in
27640 the type. */
27642 tree
27644 {
27645 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
27647 }
27649 /* Return truthvalue if we're processing a template different from
27650 the last one involved in diagnostics. */
27651 bool
27653 {
27655 }
27657 /* Remember current template involved in diagnostics. */
27658 void
27660 {
27662 }
27666 {
27668 }
27670 /* Return TRUE if current_function_decl is being instantiated, false
27671 otherwise. */
27673 bool
27675 {
27679 }
27681 /* [temp.param] Check that template non-type parm TYPE is of an allowable
27682 type. Return false for ok, true for disallowed. Issue error and
27683 inform messages under control of COMPLAIN. */
27685 static bool
27687 {
27698 {
27700 {
27705 }
27707 }
27712 /* Fall through; before C++11 alias templates, a bound ttp
27715 /* Any other wildcard type not already handled above is allowed. */
27722 {
27730 {
27731 auto_diagnostic_group d;
27735 }
27737 }
27739 {
27744 }
27747 {
27750 else
27752 type);
27753 }
27755 }
27757 /* Returns true iff the noexcept-specifier for TYPE is value-dependent. */
27759 static bool
27761 {
27764 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
27765 affect overload resolution and treating it as dependent breaks
27766 things. Same for an unparsed noexcept expression. */
27773 }
27775 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
27776 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
27778 static bool
27780 {
27781 tree scope;
27783 /* [temp.dep.type]
27785 A type is dependent if it is:
27787 -- a template parameter. Template template parameters are types
27788 for us (since TYPE_P holds true for them) so we handle
27789 them here. */
27793 /* -- a qualified-id with a nested-name-specifier which contains a
27794 class-name that names a dependent type or whose unqualified-id
27795 names a dependent type. */
27799 /* An alias template specialization can be dependent even if the
27800 resulting type is not. */
27804 /* -- a cv-qualified type where the cv-unqualified type is
27805 dependent.
27806 No code is necessary for this bullet; the code below handles
27807 cv-qualified types, and we don't want to strip aliases with
27808 TYPE_MAIN_VARIANT because of DR 1558. */
27809 /* -- a compound type constructed from any dependent type. */
27817 {
27818 tree arg_type;
27823 arg_type;
27829 /* A value-dependent noexcept-specifier makes the type dependent. */
27832 }
27833 /* -- an array type constructed from any dependent type or whose
27834 size is specified by a constant expression that is
27835 value-dependent.
27837 We checked for type- and value-dependence of the bounds in
27838 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
27840 {
27845 }
27847 /* -- a template-id in which either the template name is a template
27848 parameter ... */
27851 /* ... or any of the template arguments is a dependent type or
27852 an expression that is type-dependent or value-dependent. */
27854 && (any_dependent_template_arguments_p
27858 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and TRAIT_TYPEs are
27859 dependent; if the argument of the `typeof' expression is not
27860 type-dependent, then it should already been have resolved. */
27866 /* A template argument pack is dependent if any of its packed
27867 arguments are. */
27869 {
27874 }
27876 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
27877 be template parameters. */
27887 /* The standard does not specifically mention types that are local
27888 to template functions or local classes, but they should be
27889 considered dependent too. For example:
27891 template <int I> void f() {
27892 enum E { a = I };
27893 S<sizeof (E)> s;
27894 }
27896 The size of `E' cannot be known until the value of `I' has been
27897 determined. Therefore, `E' must be considered dependent. */
27901 /* Don't use type_dependent_expression_p here, as it can lead
27902 to infinite recursion trying to determine whether a lambda
27903 nested in a lambda is dependent (c++/47687). */
27907 && (any_dependent_template_arguments_p
27911 /* Other types are non-dependent. */
27913 }
27915 /* Returns TRUE if TYPE is dependent, in the sense of
27916 [temp.dep.type]. Note that a NULL type is considered dependent. */
27918 bool
27920 {
27921 /* If there are no template parameters in scope, then there can't be
27922 any dependent types. */
27924 {
27925 /* If we are not processing a template, then nobody should be
27926 providing us with a dependent type. */
27930 }
27932 /* If the type is NULL, we have not computed a type for the entity
27933 in question; in that case, the type is dependent. */
27937 /* Erroneous types can be considered non-dependent. */
27941 /* If we have not already computed the appropriate value for TYPE,
27942 do so now. */
27944 {
27947 }
27950 }
27952 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
27953 lookup. In other words, a dependent type that is not the current
27954 instantiation. */
27956 bool
27958 {
27961 }
27963 /* True if we might find more declarations in SCOPE during instantiation than
27964 we can when parsing the template. */
27966 bool
27968 {
27970 }
27972 /* T is a SCOPE_REF. Return whether it represents a non-static member of
27973 an unknown base of 'this' (and is therefore instantiation-dependent). */
27975 static bool
27977 {
27994 }
27996 /* T is a SCOPE_REF; return whether we need to consider it
27997 instantiation-dependent so that we can check access at instantiation
27998 time even though we know which member it resolves to. */
28000 static bool
28002 {
28010 else
28012 }
28014 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
28015 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
28016 expression. */
28018 /* Note that this predicate is not appropriate for general expressions;
28019 only constant expressions (that satisfy potential_constant_expression)
28020 can be tested for value dependence. */
28022 bool
28024 {
28028 /* A type-dependent expression is also value-dependent. */
28033 {
28035 /* A dependent member function of the current instantiation. */
28039 /* A dependent member function of the current instantiation. */
28046 /* A name that has not been looked up -- must be dependent. */
28050 /* A non-type template parm. */
28054 /* A non-type template parm. */
28060 /* A constant with literal type and is initialized
28061 with an expression that is value-dependent. */
28065 {
28068 /* __PRETTY_FUNCTION__ inside a template function is dependent
28069 on the name of the function. */
28071 /* It might be used in a template, but not a template
28072 function, in which case its DECL_VALUE_EXPR will be
28073 "top level". */
28076 }
28078 /* FIXME cp_finish_decl doesn't fold reference initializers. */
28080 /* We have a constexpr variable and we're processing a template. When
28081 there's lifetime extension involved (for which finish_compound_literal
28082 used to create a temporary), we'll not be able to evaluate the
28083 variable until instantiating, so pretend it's value-dependent. */
28095 /* These expressions are value-dependent if the type to which
28096 the cast occurs is dependent or the expression being casted
28097 is value-dependent. */
28098 {
28104 /* A functional cast has a list of operands. */
28107 {
28108 /* If there are no operands, it must be an expression such
28109 as "int()". This should not happen for aggregate types
28110 because it would form non-constant expressions. */
28115 }
28125 }
28130 /* FALLTHRU */
28133 /* A `sizeof' expression is value-dependent if the operand is
28134 type-dependent or is a pack expansion. */
28143 /* An 'encode' expression is value-dependent if the operand is
28144 type-dependent. */
28153 /* All instantiation-dependent expressions should also be considered
28154 value-dependent. */
28162 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
28163 is value-dependent. */
28170 {
28186 }
28197 {
28201 }
28204 /* Treat all requires-expressions as value-dependent so
28205 we don't try to fold them. */
28212 {
28219 {
28221 /* In a call to a constexpr member function, look through the
28222 implicit ADDR_EXPR on the object argument so that it doesn't
28223 cause the call to be considered value-dependent. We also
28224 look through it in potential_constant_expression. */
28231 }
28233 }
28240 {
28242 tree val;
28249 }
28252 /* Treat a GNU statement expression as dependent to avoid crashing
28253 under instantiate_non_dependent_expr; it can't be constant. */
28258 /* The second operand is a type, which type_dependent_expression_p
28259 (and therefore value_dependent_expression_p) doesn't want to see. */
28265 /* A constant expression is value-dependent if any subexpression is
28266 value-dependent. */
28268 {
28275 {
28279 {
28282 /* In some cases, some of the operands may be missing.
28283 (For example, in the case of PREDECREMENT_EXPR, the
28284 amount to increment by may be missing.) That doesn't
28285 make the expression dependent. */
28288 }
28289 }
28293 }
28295 }
28297 /* The expression is not value-dependent. */
28299 }
28301 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
28302 [temp.dep.expr]. Note that an expression with no type is
28303 considered dependent. Other parts of the compiler arrange for an
28304 expression with type-dependent subexpressions to have no type, so
28305 this function doesn't have to be fully recursive. */
28307 bool
28309 {
28320 /* An unresolved name is always dependent. */
28326 /* A lambda-expression in template context is dependent. dependent_type_p is
28327 true for a lambda in the scope of a class or function template, but that
28328 doesn't cover all template contexts, like a default template argument. */
28332 /* A fold expression is type-dependent. */
28339 /* Some expression forms are never type-dependent. */
28352 /* The types of these expressions depends only on the type to which
28353 the cast occurs. */
28362 /* The types of these expressions depends only on the type created
28363 by the expression. */
28366 {
28367 /* For NEW_EXPR tree nodes created inside a template, either
28368 the object type itself or a TREE_LIST may appear as the
28369 operand 1. */
28372 /* This is an array type. We need to check array dimensions
28373 as well. */
28375 || value_dependent_expression_p
28377 /* Array type whose dimension has to be deduced. */
28381 else
28383 }
28386 {
28390 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
28391 contains an identifier associated by name lookup with one or more
28392 declarations declared with a dependent type, or...a
28393 nested-name-specifier or qualified-id that names a member of an
28394 unknown specialization. */
28397 }
28407 {
28412 }
28414 /* A static data member of the current instantiation with incomplete
28415 array type is type-dependent, as the definition and specializations
28416 can have different bounds. */
28423 /* An array of unknown bound depending on a variadic parameter, eg:
28425 template<typename... Args>
28426 void foo (Args... args)
28427 {
28428 int arr[] = { args... };
28429 }
28431 template<int... vals>
28432 void bar ()
28433 {
28434 int arr[] = { vals... };
28435 }
28437 If the array has no length and has an initializer, it must be that
28438 we couldn't determine its length in cp_complete_array_type because
28439 it is dependent. */
28447 /* Pull a FUNCTION_DECL out of a BASELINK if we can. */
28449 {
28454 }
28456 /* A function or variable template-id is type-dependent if it has any
28457 dependent template arguments. */
28461 {
28462 /* Consider the innermost template arguments, since those are the ones
28463 that come from the template-id; the template arguments for the
28464 enclosing class do not make it type-dependent unless they are used in
28465 the type of the decl. */
28467 && (any_dependent_template_arguments_p
28470 }
28472 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
28473 type-dependent. Checking this is important for functions with auto return
28474 type, which looks like a dependent type. */
28483 {
28487 }
28489 /* Otherwise, its constraints could still depend on outer template parameters
28490 from its (dependent) scope. */
28492 /* As an optimization, check this cheaper sufficient condition first.
28493 (At this point we've established that we're looking at a member of
28494 a dependent class, so it makes sense to start treating say undeduced
28495 auto as dependent.) */
28500 /* Always dependent, on the number of arguments if nothing else. */
28505 {
28510 {
28516 }
28517 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
28521 /* CO_AWAIT/YIELD_EXPR with unknown type is always dependent. */
28527 {
28532 }
28535 {
28542 }
28551 }
28553 /* The type of a non-type template parm declared with a placeholder type
28554 depends on the corresponding template argument, even though
28555 placeholders are not normally considered dependent. */
28562 /* Dependent type attributes might not have made it from the decl to
28563 the type yet. */
28569 }
28571 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
28572 type-dependent if the expression refers to a member of the current
28573 instantiation and the type of the referenced member is dependent, or the
28574 class member access expression refers to a member of an unknown
28575 specialization.
28577 This function returns true if the OBJECT in such a class member access
28578 expression is of an unknown specialization. */
28580 bool
28582 {
28583 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
28584 dependent. */
28589 }
28591 /* walk_tree callback function for instantiation_dependent_expression_p,
28592 below. Returns non-zero if a dependent subexpression is found. */
28594 static tree
28597 {
28599 {
28600 /* We don't have to worry about decltype currently because decltype
28601 of an instantiation-dependent expr is a dependent type. This
28602 might change depending on the resolution of DR 1172. */
28605 }
28608 {
28609 /* Don't treat an argument list as dependent just because it has no
28610 TREE_TYPE. */
28621 /* We'll check value-dependence separately. */
28624 /* Handle expressions with type operands. */
28629 {
28634 {
28637 else
28638 {
28641 }
28642 }
28644 }
28648 /* In a template, finish_class_member_access_expr creates a
28649 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
28650 type-dependent, so that we can check access control at
28651 instantiation time (PR 42277). See also Core issue 1273. */
28658 else
28661 /* Treat statement-expressions as dependent. */
28665 /* Treat requires-expressions as dependent. */
28676 /* Before C++17, a noexcept-specifier isn't part of the function type
28677 so it doesn't affect type dependence, but we still want to consider it
28678 for instantiation dependence. */
28687 }
28691 else
28693 }
28695 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
28696 sense defined by the ABI:
28698 "An expression is instantiation-dependent if it is type-dependent
28699 or value-dependent, or it has a subexpression that is type-dependent
28700 or value-dependent."
28702 Except don't actually check value-dependence for unevaluated expressions,
28703 because in sizeof(i) we don't care about the value of i. Checking
28704 type-dependence will in turn check value-dependence of array bounds/template
28705 arguments as needed. */
28707 bool
28709 {
28710 tree result;
28721 }
28723 /* As above, but also check value-dependence of the expression as a whole. */
28725 bool
28727 {
28729 || (processing_template_decl
28732 }
28734 /* Like type_dependent_expression_p, but it also works while not processing
28735 a template definition, i.e. during substitution or mangling. */
28737 bool
28739 {
28745 }
28747 /* Returns TRUE if ARGS contains a type-dependent expression. */
28749 bool
28751 {
28760 }
28762 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
28763 expressions) contains any type-dependent expressions. */
28765 bool
28767 {
28773 }
28775 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
28776 expressions) contains any value-dependent expressions. */
28778 bool
28780 {
28786 }
28788 /* Returns TRUE if the ARG (a template argument) is dependent. */
28790 bool
28792 {
28796 /* Assume a template argument that was wrongly written by the user
28797 is dependent. This is consistent with what
28798 any_dependent_template_arguments_p [that calls this function]
28799 does. */
28809 {
28812 /* A member template of a dependent class is not necessarily
28813 type-dependent, but it is a dependent template argument because it
28814 will be a member of an unknown specialization to that template. */
28817 }
28819 {
28825 }
28828 else
28830 }
28832 /* Identify any expressions that use function parms. */
28834 static tree
28836 {
28839 {
28842 }
28844 }
28846 /* Returns true if a type specialization formed using the template
28847 arguments ARGS needs to use structural equality. */
28849 bool
28851 {
28861 {
28864 {
28870 {
28871 /* Look inside the argument pack. */
28874 }
28877 {
28886 /* An any_targ_node argument (added by add_defaults_to_ttp)
28887 makes the corresponding specialization not canonicalizable,
28888 since template_args_equal always return true for it. We
28889 may see this when called from bind_template_template_parm. */
28891 /* Checking current_function_decl because this structural
28892 comparison is only necessary for redeclaration. */
28895 && (cp_walk_tree_without_duplicates
28897 /* The identity of a class template specialization that uses
28898 a function parameter depends on the identity of the function.
28899 And if this specialization appeared in the trailing return
28900 type thereof, we don't know the identity of the function
28901 (e.g. if it's a redeclaration or a new function) until we
28902 form its signature and go through duplicate_decls. Thus
28903 it's unsafe to decide on a canonical type now (which depends
28904 on the DECL_CONTEXT of the function parameter, which can get
28905 mutated after the fact by duplicate_decls), so just require
28906 structural equality in this case (PR52830). */
28911 /* Require structural equality for specializations written
28912 in terms of a dependent alias template specialization. */
28917 /* Require structural equality for specializations written
28918 in terms of a class template specialization that itself
28919 needs structural equality. */
28921 }
28922 }
28923 }
28926 }
28928 /* Returns true if ARGS (a collection of template arguments) contains
28929 any dependent arguments. */
28931 bool
28933 {
28940 {
28945 }
28948 }
28950 /* Returns true if ARGS contains any errors. */
28952 bool
28954 {
28962 {
28965 else
28967 }
28973 {
28978 }
28981 }
28983 /* Returns TRUE if the template TMPL is type-dependent. */
28985 bool
28987 {
28989 {
28994 }
28996 /* Template template parameters are dependent. */
29000 /* So are names that have not been looked up. */
29004 }
29006 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
29008 bool
29010 {
29013 }
29015 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
29016 are dependent. */
29018 bool
29020 {
29027 {
29052 {
29056 }
29060 {
29064 {
29070 /* If this loop has a class iterator with != comparison
29071 with increment other than i++/++i/i--/--i, make sure the
29072 increment is constant. */
29075 {
29078 else
29082 }
29083 }
29084 }
29085 }
29088 }
29090 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
29091 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
29092 no such TYPE can be found. Note that this function peers inside
29093 uninstantiated templates and therefore should be used only in
29094 extremely limited situations. ONLY_CURRENT_P restricts this
29095 peering to the currently open classes hierarchy (which is required
29096 when comparing types). */
29098 tree
29100 {
29101 tree scope;
29102 tree name;
29103 tree decl;
29105 tree pushed_scope;
29106 tree result;
29111 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
29114 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
29115 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of a
29116 TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL
29117 representing the typedef. In that case TYPE_IDENTIFIER (type) is
29118 not the non-qualified identifier of the TYPENAME_TYPE anymore.
29119 So by getting the TYPE_IDENTIFIER of the _main declaration_ of
29120 the TYPENAME_TYPE instead, we avoid messing up with a possible
29121 typedef variant case. */
29124 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
29125 it first before we can figure out what NAME refers to. */
29127 {
29129 /* Given a class template A with a dependent base with nested type C,
29130 typedef typename A::C::C C will land us here, as trying to resolve
29131 the initial A::C leads to the local C typedef, which leads back to
29132 A::C::C. So we break the recursion now. */
29134 else
29136 }
29137 /* If we don't know what SCOPE refers to, then we cannot resolve the
29138 TYPENAME_TYPE. */
29141 /* If this is a typedef, we don't want to look inside (c++/11987). */
29144 /* If SCOPE isn't the template itself, it will not have a valid
29145 TYPE_FIELDS list. */
29147 /* scope is either the template itself or a compatible instantiation
29148 like X<T>, so look up the name in the original template. */
29150 /* If scope has no fields, it can't be a current instantiation. Check this
29151 before currently_open_class to avoid infinite recursion (71515). */
29154 /* If the SCOPE is not the current instantiation, there's no reason
29155 to look inside it. */
29158 /* Enter the SCOPE so that name lookup will be resolved as if we
29159 were in the class definition. In particular, SCOPE will no
29160 longer be considered a dependent type. */
29162 /* Look up the declaration. */
29164 tf_warning_or_error);
29168 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
29169 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
29175 {
29179 }
29182 {
29183 /* Obtain the template and the arguments. */
29186 {
29187 /* We get here with a plain identifier because a previous tentative
29188 parse of the nested-name-specifier as part of a ptr-operator saw
29189 ::template X<A>. The use of ::template is necessary in a
29190 ptr-operator, but wrong in a declarator-id.
29192 [temp.names]: In a qualified-id of a declarator-id, the keyword
29193 template shall not appear at the top level. */
29197 }
29199 /* Instantiate the template. */
29205 }
29207 /* Leave the SCOPE. */
29211 /* If we failed to resolve it, return the original typename. */
29215 /* If lookup found a typename type, resolve that too. */
29217 {
29218 /* Ill-formed programs can cause infinite recursion here, so we
29219 must catch that. */
29223 }
29225 /* Qualify the resulting type. */
29231 }
29233 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
29234 TEMPLATE_TYPE_PARM with a level one deeper than the actual template parms,
29235 by default. If set_canonical is true, we set TYPE_CANONICAL on it. */
29237 static tree
29239 {
29255 }
29257 tree
29259 {
29261 }
29263 tree
29265 {
29267 }
29269 /* Return a C++17 deduction placeholder for class template TMPL.
29270 There are represented as an 'auto' with the special level 0 and
29271 CLASS_PLACEHOLDER_TEMPLATE set. */
29273 tree
29275 {
29278 /* Our canonical type depends on the placeholder. */
29281 }
29283 /* True iff T is a C++17 class template deduction placeholder. */
29285 bool
29287 {
29289 }
29291 /* Make a "constrained auto" type-specifier. This is an auto or
29292 decltype(auto) type with constraints that must be associated after
29293 deduction. The constraint is formed from the given concept CON
29294 and its optional sequence of template arguments ARGS.
29296 TYPE must be the result of make_auto_type or make_decltype_auto_type. */
29298 static tree
29300 {
29301 /* Build the constraint. */
29313 /* Our canonical type depends on the constraint. */
29316 /* Attach the constraint to the type declaration. */
29318 }
29320 /* Make a "constrained auto" type-specifier. */
29322 tree
29324 {
29327 }
29329 /* Make a "constrained decltype(auto)" type-specifier. */
29331 tree
29333 {
29336 }
29338 /* Returns true if the placeholder type constraint T has any dependent
29339 (explicit) template arguments. */
29341 static bool
29343 {
29348 {
29351 }
29358 }
29360 /* Build and return a concept definition. Like other templates, the
29361 CONCEPT_DECL node is wrapped by a TEMPLATE_DECL. This returns the
29362 the TEMPLATE_DECL. */
29364 tree
29366 {
29372 /* A concept-definition shall not have associated constraints. */
29374 {
29377 }
29379 /* A concept-definition shall appear in namespace scope. Templates
29380 aren't allowed in block scope, so we only need to check for class
29381 scope. */
29383 {
29386 }
29389 {
29392 }
29394 /* Initially build the concept declaration; its type is bool. */
29404 /* Push the enclosing template. */
29406 }
29408 /* Given type ARG, return std::initializer_list<ARG>. */
29410 static tree
29412 {
29417 {
29421 "deducing from brace-enclosed initializer list"
29425 }
29431 }
29433 /* Replace auto in TYPE with std::initializer_list<auto>. */
29435 static tree
29437 {
29444 }
29446 /* Hash traits for hashing possibly constrained 'auto'
29447 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
29450 {
29453 };
29455 /* Hash the 'auto' T. */
29457 inline hashval_t
29459 {
29461 /* Matching constrained-type-specifiers denote the same template
29462 parameter, so hash the constraint. */
29464 else
29465 /* But unconstrained autos are all separate, so just hash the pointer. */
29467 }
29469 /* Compare two 'auto's. */
29473 {
29480 /* Two unconstrained autos are distinct. */
29485 }
29487 /* for_each_template_parm callback for extract_autos: if t is a (possibly
29488 constrained) auto, add it to the vector. */
29490 static int
29492 {
29495 {
29496 /* All the autos were built with index 0; fix that up now. */
29500 /* If this is a repeated constrained-type-specifier, use the index we
29501 chose before. */
29503 else
29504 {
29505 /* Otherwise this is new, so use the current count. */
29508 }
29510 {
29515 }
29516 }
29518 /* Always keep walking. */
29520 }
29522 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
29523 says they can appear anywhere in the type. */
29525 static tree
29527 {
29535 {
29539 }
29542 }
29544 /* The stem for deduction guide names. */
29547 /* Return the name for a deduction guide for class template TMPL. */
29549 tree
29551 {
29562 }
29564 /* True if NAME is the name of a deduction guide. */
29566 bool
29568 {
29572 }
29574 /* True if FN is a deduction guide. */
29576 bool
29578 {
29583 }
29585 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
29587 bool
29589 {
29596 }
29598 /* True if FN is a guide generated from a constructor template. */
29600 bool
29602 {
29610 }
29612 /* True if FN is an aggregate initialization guide or the copy deduction
29613 guide. */
29615 bool
29617 {
29621 /* Explicitly declared. */
29624 /* Derived from a constructor. */
29627 }
29629 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
29630 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
29631 template parameter types. Note that the handling of template template
29632 parameters relies on current_template_parms being set appropriately for the
29633 new template. */
29635 static tree
29638 {
29644 tree newtype;
29647 {
29651 }
29652 else
29653 {
29656 {
29657 // Substitute once to fix references to other template parameters.
29660 // Now substitute again to reduce the level of the auto.
29663 }
29664 else
29667 }
29669 tree newdecl
29674 tree newidx;
29677 {
29686 {
29687 tree newresult
29692 // First create a copy (ttargs) of tsubst_args with an
29693 // additional level for the template template parameter's own
29694 // template parameters (ttparms).
29695 tree ttparms = (INNERMOST_TEMPLATE_PARMS
29703 // Substitute ttargs into ttparms to fix references to
29704 // other template parameters.
29707 // Now substitute again with args based on tparms, to reduce
29708 // the level of the ttparms.
29711 complain);
29712 // Finally, tack the adjusted parms onto tparms.
29715 // As with all template template parms, the parameter list captured
29716 // by this template template parm that corresponds to its own level
29717 // should be empty. This avoids infinite recursion when structurally
29718 // comparing two such rewritten template template parms (PR102479).
29723 // All done.
29727 }
29731 else
29733 }
29734 else
29735 {
29737 tree newconst
29749 }
29752 }
29754 /* As rewrite_template_parm, but for the whole TREE_LIST representing a
29755 template parameter. */
29757 static tree
29760 {
29775 }
29777 /* Returns a C++17 class deduction guide template based on the constructor
29778 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
29779 guide, REFERENCE_TYPE for an implicit copy/move guide, or TREE_LIST for an
29780 aggregate initialization guide. OUTER_ARGS are the template arguments
29781 for the enclosing scope of the class. */
29783 static tree
29785 {
29789 location_t loc;
29793 {
29797 }
29800 {
29802 {
29806 else
29808 }
29811 else
29821 }
29822 else
29823 {
29829 fn_tmpl
29837 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
29838 fully specialized args for the enclosing class. Strip those off, as
29839 the deduction guide won't have those template parameters. */
29842 /* Discard the 'this' parameter. */
29850 {
29853 /* For a member template constructor, we need to flatten the two
29854 template parameter lists into one, and then adjust the function
29855 signature accordingly. This gets...complicated. */
29858 /* For a member template we should have two levels of parms/args, one
29859 for the class and one for the constructor. We stripped
29860 specialized args for further enclosing classes above. */
29864 /* Template args for translating references to the two-level template
29865 parameters into references to the one-level template parameters we
29866 are creating. */
29871 /* Template parms for the constructor template. */
29874 /* Template parms for the class template. */
29878 /* Template parms for the deduction guide start as a copy of the
29879 template parms for the class. We set current_template_parms for
29880 lookup_template_class_1. */
29886 /* Now we need to rewrite the constructor parms to append them to the
29887 class parms. */
29889 {
29893 tree newelt
29899 }
29901 /* Now we have a final set of template parms to substitute into the
29902 function signature. */
29909 {
29911 /* FIXME: We'd like to avoid substituting outer template
29912 arguments into the constraint ahead of time, but the
29913 construction of tsubst_args assumes that outer arguments
29914 are already substituted in. */
29917 }
29919 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped if
29920 cp_unevaluated_operand. */
29921 cp_evaluated ev;
29924 }
29925 else
29926 {
29927 /* Substitute in the same arguments to rewrite class members into
29928 references to members of an unknown specialization. */
29929 cp_evaluated ev;
29933 {
29935 /* FIXME: As above. */
29938 }
29939 }
29944 }
29947 {
29948 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
29952 }
29956 FUNCTION_DECL,
29971 }
29973 /* Add to LIST the member types for the reshaped initializer CTOR. */
29975 static tree
29977 {
29981 {
29985 {
29991 }
29995 /* Give the trailing pack expansion parameter a default argument to
29996 match aggregate initialization behavior, even if we deduce the
29997 length of the pack separately to more than we have initializers. */
29999 /* if ei is of array type and xi is a braced-init-list or string literal,
30000 Ti is an rvalue reference to the declared type of ei */
30005 {
30007 ftype = cp_build_qualified_type
30009 ftype = (cp_build_reference_type
30011 }
30013 }
30016 }
30018 /* Return whether ETYPE is, or is derived from, a specialization of TMPL. */
30020 static bool
30022 {
30028 tree tparms = (INNERMOST_TEMPLATE_PARMS
30035 }
30037 /* Return a C++20 aggregate deduction candidate for TYPE initialized from
30038 INIT. */
30040 static tree
30042 {
30050 {
30056 }
30058 /* We might be creating a guide for a class member template, e.g.,
30060 template<typename U> struct A {
30061 template<typename T> struct B { T t; };
30062 };
30064 At this point, A will have been instantiated. Below, we need to
30065 use both A<U>::B<T> (TEMPLATE_TYPE) and A<int>::B<T> (TYPE) types. */
30066 const bool member_template_p
30070 tree template_type = (member_template_p
30076 /* No aggregate candidate for copy-initialization. */
30078 {
30082 }
30084 /* If we encounter a problem, we just won't add the candidate. */
30089 {
30094 /* If we're creating a deduction guide for a member class template,
30095 we've used the original template pattern type for the reshape_init
30096 above; this is done because we want PARMS to be a template parameter
30097 type, something that can be deduced when used as a function template
30098 parameter. At this point the outer class template has already been
30099 partially instantiated (we deferred the deduction until the enclosing
30100 scope is non-dependent). Therefore we have to partially instantiate
30101 PARMS, so that its template level is properly reduced and we don't get
30102 mismatches when deducing types using the guide with PARMS. */
30104 {
30108 }
30109 }
30111 {
30114 len;
30116 {
30122 }
30123 }
30124 else
30125 /* Aggregate initialization doesn't apply to an initializer expression. */
30129 {
30135 }
30138 }
30140 /* UGUIDES are the deduction guides for the underlying template of alias
30141 template TMPL; adjust them to be deduction guides for TMPL.
30143 This routine also handles C++23 inherited CTAD, in which case TMPL is a
30144 TREE_LIST representing a synthetic alias template whose TREE_PURPOSE is
30145 the template parameter list of the alias template (equivalently, of the
30146 derived class) and TREE_VALUE the defining-type-id (equivalently, the
30147 base whose guides we're inheriting). UGUIDES are the base's guides. */
30149 static tree
30151 {
30152 /* [over.match.class.deduct]: When resolving a placeholder for a deduced
30153 class type (9.2.8.2) where the template-name names an alias template A,
30154 the defining-type-id of A must be of the form
30156 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
30158 as specified in 9.2.8.2. The guides of A are the set of functions or
30159 function templates formed as follows. For each function or function
30160 template f in the guides of the template named by the simple-template-id
30161 of the defining-type-id, the template arguments of the return type of f
30162 are deduced from the defining-type-id of A according to the process in
30163 13.10.2.5 with the exception that deduction does not fail if not all
30164 template arguments are deduced. Let g denote the result of substituting
30165 these deductions into f. If substitution succeeds, form a function or
30166 function template f' with the following properties and add it to the set
30167 of guides of A:
30169 * The function type of f' is the function type of g.
30171 * If f is a function template, f' is a function template whose template
30172 parameter list consists of all the template parameters of A (including
30173 their default template arguments) that appear in the above deductions or
30174 (recursively) in their default template arguments, followed by the
30175 template parameters of f that were not deduced (including their default
30176 template arguments), otherwise f' is not a function template.
30178 * The associated constraints (13.5.2) are the conjunction of the
30179 associated constraints of g and a constraint that is satisfied if and only
30180 if the arguments of A are deducible (see below) from the return type.
30182 * If f is a copy deduction candidate (12.4.1.8), then f' is considered to
30183 be so as well.
30185 * If f was generated from a deduction-guide (12.4.1.8), then f' is
30186 considered to be so as well.
30188 * The explicit-specifier of f' is the explicit-specifier of g (if
30189 any). */
30194 {
30199 }
30200 else
30201 {
30206 }
30213 {
30220 {
30224 /* Deduce template arguments for f from the type-id of A. */
30230 /* CWG2664: Discard any deductions, still build the guide. */
30234 /* The number of parms for f' is the number of parms of A used in
30235 the deduced arguments plus non-deduced parms of f. */
30247 /* Set current_template_parms as in build_deduction_guide. */
30255 /* First copy over the used parms of A. */
30258 {
30261 {
30266 }
30267 }
30270 /* Adjust the deduced template args for f to refer to the A parms
30271 with their new indexes. */
30275 /* Now rewrite the non-deduced parms of f. */
30278 {
30285 }
30288 /* Substitute the deduced arguments plus the rewritten template
30289 parameters into f to get g. This covers the type, copyness,
30290 guideness, and explicit-specifier. */
30291 tree g;
30292 {
30293 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped
30294 if cp_unevaluated_operand. */
30295 cp_evaluated ev;
30298 }
30302 {
30303 /* The targs are all non-dependent, so g isn't a template. */
30307 }
30316 /* Substitute the associated constraints. */
30323 /* Add a constraint that the return type matches the instantiation of
30324 A with the same template arguments. */
30328 /* FIXME this should mean they don't compare as equivalent. */
30330 {
30333 }
30336 {
30339 }
30340 }
30341 else
30342 {
30343 /* For a non-template deduction guide, if the arguments of A aren't
30344 deducible from the return type, don't add the candidate. */
30345 non_template:
30349 }
30351 /* Rewrite the return type of the inherited guide in terms of the
30352 derived class. This is specified as replacing the return type R
30353 with typename CC<R>::type where the partially specialized CC maps a
30354 base class specialization to a specialization of the derived class
30355 having such a base (inducing substitution failure if no such derived
30356 class exists).
30358 As specified this mapping would be done at instantiation time using
30359 non-dependent template arguments, but we do it ahead of time using
30360 the generic arguments. This seems to be good enough since generic
30361 deduction should succeed only if concrete deduction would. */
30363 {
30381 }
30384 }
30387 }
30389 /* CTOR is a using-decl inheriting the constructors of some base of the class
30390 template TMPL; adjust the base's guides be deduction guides for TMPL. */
30392 static tree
30394 {
30395 /* [over.match.class.deduct]: In addition, if C is defined and inherits
30396 constructors ([namespace.udecl]) from a direct base class denoted in the
30397 base-specifier-list by a class-or-decltype B, let A be an alias template
30398 whose template parameter list is that of C and whose defining-type-id is
30399 B. If A is a deducible template ([dcl.type.simple]), the set contains the
30400 guides of A with the return type R of each guide replaced with typename
30401 CC::type given a class template
30403 template <typename> class CC;
30405 whose primary template is not defined and with a single partial
30406 specialization whose template parameter list is that of A and whose
30407 template argument list is a specialization of A with the template argument
30408 list of A ([temp.dep.type]) having a member typedef type designating a
30409 template specialization with the template argument list of A but with C as
30410 the template. */
30412 /* FIXME: Also recognize inherited constructors of the form 'using C::B::B',
30413 which seem to be represented with TYPENAME_TYPE C::B as USING_DECL_SCOPE?
30414 And recognize constructors inherited from a non-dependent base class, which
30415 seem to be missing from the overload set entirely? */
30427 }
30429 /* If template arguments for TMPL can be deduced from TYPE, return
30430 the deduced arguments, otherwise return NULL_TREE.
30431 Used to implement CPTK_IS_DEDUCIBLE for alias CTAD according to
30432 [over.match.class.deduct].
30434 This check is specified in terms of partial specialization, so the behavior
30435 should be parallel to that of get_partial_spec_bindings. */
30437 tree
30439 {
30442 {
30443 /* If tmpl is a class template, this is trivial: it's deducible if
30444 TYPE is a specialization of TMPL. */
30446 {
30451 else
30453 }
30455 /* Otherwise it's an alias template. */
30458 }
30459 else
30460 {
30461 /* TMPL is a synthetic alias template represented as a TREE_LIST as
30462 per alias_ctad_tweaks. */
30466 }
30472 again:
30477 /* We don't fail on an undeduced targ the second time through (like
30478 get_partial_spec_bindings) because we're going to try defaults. */
30481 {
30487 {
30492 }
30493 /* If the type parameter is a parameter pack, then it will be deduced
30494 to an empty parameter pack. This is another case that doesn't model
30495 well as partial specialization. */
30497 {
30498 tree arg;
30500 {
30503 }
30504 else
30508 }
30509 }
30511 /* Maybe add in default template args. This seems like a flaw in the
30512 specification in terms of partial specialization, since it says the
30513 partial specialization has the the template parameter list of A, but a
30514 partial specialization can't have default targs. */
30519 /* I believe we don't need the template_template_parm_bindings_ok_p call
30520 because coerce_template_parms did coerce_template_template_parms. */
30526 }
30528 /* Return artificial deduction guides built from the constructors of class
30529 template TMPL. */
30531 static tree
30533 {
30540 {
30541 /* We handle C++23 inherited CTAD below. */
30547 }
30552 {
30556 }
30558 /* Add implicit default constructor deduction guide. */
30560 {
30562 complain);
30564 }
30566 /* Add copy guide. */
30567 {
30570 complain);
30572 }
30575 }
30579 /* Return the non-aggregate deduction guides for deducible template TMPL. The
30580 aggregate candidate is added separately because it depends on the
30581 initializer. Set ANY_DGUIDES_P if we find a non-implicit deduction
30582 guide. */
30584 static tree
30586 {
30589 {
30593 complain);
30594 }
30595 else
30596 {
30602 else
30604 }
30606 /* Cache the deduction guides for a template. We also remember the result of
30607 lookup, and rebuild everything if it changes; should be very rare. */
30608 /* FIXME: Also rebuild if this is a class template that inherits guides from a
30609 base class, and lookup for the latter changed. */
30613 {
30617 }
30618 else
30619 {
30622 }
30627 else
30628 {
30632 }
30636 }
30638 /* Return whether TMPL is a (class template argument-) deducible template. */
30640 bool
30642 {
30643 /* A deducible template is either a class template or is an alias template
30644 whose defining-type-id is of the form
30646 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
30648 where the nested-name-specifier (if any) is non-dependent and the
30649 template-name of the simple-template-id names a deducible template. */
30660 }
30662 /* Deduce template arguments for the class template placeholder PTYPE for
30663 template TMPL based on the initializer INIT, and return the resulting
30664 type. */
30666 static tree
30669 {
30670 /* We should have handled this in the caller. */
30674 /* If the class was erroneous, don't try to deduce, because that
30675 can generate a lot of diagnostic. */
30681 /* Wait until the enclosing scope is non-dependent. */
30686 /* Initializing one placeholder from another. */
30697 {
30701 }
30703 {
30705 {
30706 /* Be permissive with equivalent alias templates. */
30709 bool complained
30711 "alias template deduction only available "
30716 {
30719 }
30720 }
30721 else
30723 }
30725 /* Wait until the initializer is non-dependent. */
30729 /* Don't bother with the alias rules for an equivalent template. */
30742 {
30747 {
30748 /* As an exception, the first phase in 16.3.1.7 (considering the
30749 initializer list as a single argument) is omitted if the
30750 initializer list consists of a single expression of type cv U,
30751 where U is a specialization of C or a class derived from a
30752 specialization of C. */
30756 }
30759 else
30761 }
30764 else
30767 /* Do this now to avoid problems with erroneous args later on. */
30777 /* Prune explicit deduction guides in copy-initialization context (but
30778 not copy-list-initialization). */
30781 {
30787 {
30788 /* Found a nonconverting guide, prune the candidates. */
30795 }
30796 }
30804 /* If this is list-initialization and the class has a list guide, first
30805 try deducing from the list as a single argument, as [over.match.list]. */
30807 {
30815 {
30816 /* That didn't work, now try treating the list as a sequence of
30817 arguments. */
30823 }
30824 }
30827 {
30829 " of %qT, as it has no non-explicit deduction guides or "
30832 }
30834 {
30838 }
30844 {
30846 {
30852 }
30854 }
30855 /* [over.match.list]/1: In copy-list-initialization, if an explicit
30856 constructor is chosen, the initialization is ill-formed. */
30858 {
30860 {
30862 {
30863 // TODO: Pass down location from cp_finish_decl.
30865 "explicit deduction guide selected in "
30870 }
30872 }
30873 }
30875 /* If CTAD succeeded but the type doesn't have any explicit deduction
30876 guides, this deduction might not be what the user intended. */
30878 {
30882 "%qT may not intend to support class template argument "
30886 }
30890 }
30892 /* Return true if INIT is an unparenthesized id-expression or an
30893 unparenthesized class member access. Used for the argument of
30894 decltype(auto). */
30896 bool
30898 {
30901 /* We need to be able to tell '(r)' and 'r' apart (when it's of
30902 reference type). Only the latter is an id-expression. */
30910 }
30912 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
30913 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
30914 The CONTEXT determines the context in which auto deduction is performed
30915 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
30917 OUTER_TARGS is used during template argument deduction (context == adc_unify)
30918 to properly substitute the result. It's also used in the adc_unify and
30919 adc_requirement contexts to communicate the necessary template arguments
30920 to satisfaction. OUTER_TARGS is ignored in other contexts.
30922 Additionally for adc_unify contexts TMPL is the template for which TYPE
30923 is a template parameter type.
30925 For partial-concept-ids, extra args from OUTER_TARGS, TMPL and the current
30926 scope may be appended to the list of deduced template arguments prior to
30927 determining constraint satisfaction as appropriate. */
30929 tree
30936 {
30942 /* Defining a subset of type-dependent expressions that we can deduce
30943 from ahead of time isn't worth the trouble. */
30946 /* Similarly, we can't deduce from another undeduced decl. */
30950 /* We may be doing a partial substitution, but we still want to replace
30951 auto_node. */
30955 {
30956 /* We don't recurse here because we can't deduce from a nested
30957 initializer_list. */
30961 }
30965 /* In C++23, we must deduce the type to int&& for code like
30966 decltype(auto) f(int&& x) { return (x); }
30967 or
30968 auto&& f(int x) { return x; }
30969 so we use treat_lvalue_as_rvalue_p. But don't do it for
30970 decltype(auto) f(int x) { return x; }
30971 where we should deduce 'int' rather than 'int&&'; transmogrifying
30972 INIT to an rvalue would break that. */
30973 tree r;
30983 /* C++17 class template argument deduction. */
30987 /* Nothing we can do with this, even in deduction context. */
30992 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
30993 with either a new invented type template parameter U or, if the
30994 initializer is a braced-init-list (8.5.4), with
30995 std::initializer_list<U>. */
30997 {
31002 else
31003 {
31005 {
31009 "for deduction to %<std::initializer_list%>, use copy-"
31011 }
31013 }
31014 }
31019 tree targs;
31023 {
31024 /* [dcl.struct.bind]/1 - if decomposition declaration has no ref-qualifiers
31025 and initializer has array type, deduce cv-qualified array type. */
31028 }
31030 {
31038 }
31039 else
31040 {
31045 tree tparms;
31049 else
31050 {
31054 }
31058 DEDUCE_CALL,
31061 {
31063 /* Try again at instantiation time. */
31067 /* If type is error_mark_node a diagnostic must have been
31068 emitted by now. Also, having a mention to '<type error>'
31069 in the diagnostic is not really useful to the user. */
31070 {
31073 && (auto_node
31077 init);
31078 else
31081 DEDUCE_CALL,
31083 }
31085 }
31086 }
31088 /* Check any placeholder constraints against the deduced type. */
31092 {
31094 {
31099 /* If the constraint is dependent, we need to wait until
31100 instantiation time to resolve the placeholder. */
31103 }
31110 {
31114 {
31115 /* As in satisfy_declaration_constraints. */
31119 else
31121 }
31122 }
31129 /* HACK: Compensate for callers not always communicating all levels of
31130 outer template arguments by filling in the outermost missing levels
31131 with dummy levels before checking satisfaction. We'll still crash
31132 if the constraint depends on a template argument belonging to one of
31133 these missing levels, but this hack otherwise allows us to handle a
31134 large subset of possible constraints (including all non-dependent
31135 constraints). */
31138 {
31143 }
31146 {
31148 {
31149 auto_diagnostic_group d;
31151 {
31169 }
31171 }
31173 }
31174 }
31177 /* The outer template arguments are already substituted into type
31184 }
31186 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
31187 result. */
31189 tree
31191 {
31193 {
31196 }
31200 {
31201 /* In an abbreviated function template we didn't know we were dealing
31202 with a function template when we saw the auto return type, so rebuild
31203 the return type using an auto with the correct level. */
31208 auto_vec);
31209 /* Also rebuild the constraint info in terms of the new auto. */
31217 }
31219 }
31221 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
31222 'decltype(auto)' or a deduced class template. */
31224 bool
31226 {
31231 else
31233 }
31235 /* for_each_template_parm callback for type_uses_auto. */
31237 int
31239 {
31241 }
31243 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
31244 a use of `auto'. Returns NULL_TREE otherwise. */
31246 tree
31248 {
31252 /* For parameter packs, check the contents of the pack. */
31257 {
31258 /* The Concepts TS allows multiple autos in one type-specifier; just
31259 return the first one we find, do_auto_deduction will collect all of
31260 them. */
31264 else
31266 }
31267 else
31269 }
31271 /* Report ill-formed occurrences of auto types in ARGUMENTS. If
31272 concepts are enabled, auto is acceptable in template arguments, but
31273 only when TEMPL identifies a template class. Return TRUE if any
31274 such errors were reported. */
31276 bool
31278 {
31280 /* Only the concepts TS allows 'auto' as a type-id; it'd otherwise
31281 have already been rejected by the parser more generally. */
31284 /* If there were previous errors, nevermind. */
31288 /* If TMPL is an identifier, we're parsing and we can't tell yet
31289 whether TMPL is supposed to be a type, a function or a variable.
31290 We'll only be able to tell during template substitution, so we
31291 expect to be called again then. If concepts are enabled and we
31292 know we have a type, we're ok. */
31299 /* Quickly search for any occurrences of auto; usually there won't
31300 be any, and then we'll avoid allocating the vector. */
31308 {
31313 }
31316 }
31318 /* Recursively walk over && expressions searching for EXPR. Return a reference
31319 to that expression. */
31322 {
31326 {
31331 }
31333 }
31335 /* Convert the generic type parameters in PARM that match the types given in the
31336 range [START_IDX, END_IDX) from the current_template_parms into generic type
31337 packs. */
31339 tree
31341 {
31352 {
31353 /* Create a distinct parameter pack type from the current parm and add it
31354 to the replacement args to tsubst below into the generic function
31355 parameter. */
31369 /* Replace the current template parameter with new pack. */
31372 /* Surgically adjust the associated constraint of adjusted parameter
31373 and it's corresponding contribution to the current template
31374 requirements. */
31376 {
31379 /* Use UNKNOWN_LOCATION so write_template_args can tell the
31380 difference between this and a fold the user wrote. */
31383 TRUTH_ANDIF_EXPR);
31386 /* If there was a constraint, we also need to replace that in
31387 the template requirements, which we've already built. */
31391 }
31392 }
31398 /* If there are more levels then build up the replacement with the outer
31399 template parms. */
31403 replacement);
31406 }
31408 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
31409 0..N-1. */
31411 void
31413 {
31416 integer_type_node,
31417 NULL_TREE),
31421 CP_BUILT_IN_INTEGER_PACK);
31422 }
31424 /* Walk the decl or type specialization table calling FN on each
31425 entry. */
31427 void
31431 {
31437 }
31439 /* Lookup the specialization of *ELT, in the decl or type
31440 specialization table. Return the SPEC that's already there, or
31441 NULL if nothing. */
31443 tree
31445 {
31455 }
31457 /* Return flags encoding whether SPEC is on the instantiation and/or
31458 specialization lists of TMPL. */
31460 unsigned
31462 {
31468 {
31471 }
31476 /* Only need to search if DECL is a partial specialization. */
31480 {
31483 }
31486 }
31488 /* Add a new specialization described by SPEC. DECL is the
31489 maybe-template decl and FLAGS is as returned from
31490 get_mergeable_specialization_flags. */
31492 void
31495 {
31498 {
31507 {
31510 }
31511 }
31514 {
31517 /* We don't distinguish different constrained partial type
31518 specializations, so there could be duplicates. Everything else
31519 must be new. */
31521 {
31527 }
31528 }
31535 {
31536 /* A partial specialization. */
31541 }
31542 }
31544 /* Set up the hash tables for template instantiations. */
31546 void
31548 {
31554 }
31556 /* Print stats about the template hash tables for -fstats. */
31558 void
31560 {
31569 }
31571 #if CHECKING_P
31575 /* Verify that type_dependent_expression_p () works correctly, even
31576 in the presence of location wrapper nodes. */
31578 static void
31580 {
31585 /* If no templates are involved, nothing is type-dependent. */
31591 /* Within a template, an unresolved name is always type-dependent. */
31594 /* Ensure it copes with NULL_TREE and errors. */
31598 /* A USING_DECL in a template should be type-dependent, even if wrapped
31599 with a location wrapper (PR c++/83799). */
31608 }
31610 /* Run all of the selftests within this file. */
31612 void
31614 {
31616 }