| blob | 6b20c58ce6664c219166093b4a814a18cecfe75f |
1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2023 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. */
50 /* The type of functions taking a tree, and some additional data, and
51 returning an int. */
54 /* The PENDING_TEMPLATES is a list of templates whose instantiations
55 have been deferred, either because their definitions were not yet
56 available, or because we were putting off doing the work. */
58 {
61 };
75 /* Live only within one (recursive) call to tsubst_expr. We use
76 this to pass the statement expression node from the STMT_EXPR
77 to the EXPR_STMT that is its result. */
80 // -------------------------------------------------------------------------- //
81 // Local Specialization Stack
82 //
83 // Implementation of the RAII helper for creating new local
84 // specializations.
87 {
89 ;
92 else
94 }
97 {
99 {
102 }
103 }
105 /* True if we've recursed into fn_type_unification too many times. */
109 {
113 };
115 /* The general template is not in these tables. */
120 /* Contains canonical template parameter types. The vector is indexed by
121 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
122 TREE_LIST, whose TREE_VALUEs contain the canonical template
123 parameters of various types and levels. */
126 #define UNIFY_ALLOW_NONE 0
127 #define UNIFY_ALLOW_MORE_CV_QUAL 1
128 #define UNIFY_ALLOW_LESS_CV_QUAL 2
129 #define UNIFY_ALLOW_DERIVED 4
130 #define UNIFY_ALLOW_INTEGER 8
131 #define UNIFY_ALLOW_OUTER_LEVEL 16
132 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
133 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
136 tbr_incomplete_type,
137 tbr_ambiguous_baseclass,
138 tbr_success
139 };
224 /* Make the current scope suitable for access checking when we are
225 processing T. T can be FUNCTION_DECL for instantiated function
226 template, VAR_DECL for static member variable, or TYPE_DECL for
227 for a class or alias template (needed by instantiate_decl). */
229 void
231 {
243 /* An artificial deduction guide should have the same access as
244 the constructor. */
246 else
250 {
253 }
254 }
256 /* Restore the scope set up by push_access_scope. T is the node we
257 are processing. */
259 void
261 {
271 else
273 }
275 /* Do any processing required when DECL (a member template
276 declaration) is finished. Returns the TEMPLATE_DECL corresponding
277 to DECL, unless it is a specialization, in which case the DECL
278 itself is returned. */
280 tree
282 {
289 {
290 tree type;
298 {
302 }
304 }
309 {
311 {
314 }
315 else
317 }
318 else
323 }
325 /* Create a template info node. */
327 tree
329 {
334 }
336 /* Return the template info node corresponding to T, whatever T is. */
338 tree
340 {
362 }
364 /* Returns the template nesting level of the indicated class TYPE.
366 For example, in:
367 template <class T>
368 struct A
369 {
370 template <class U>
371 struct B {};
372 };
374 A<T>::B<U> has depth two, while A<T> has depth one.
375 Both A<T>::B<int> and A<int>::B<U> have depth one, if
376 they are instantiations, not specializations.
378 This function is guaranteed to return 0 if passed NULL_TREE so
379 that, for example, `template_class_depth (current_class_type)' is
380 always safe. */
382 int
384 {
388 {
398 {
401 else
403 }
406 else
408 }
411 }
413 /* Return TRUE if NODE instantiates a template that has arguments of
414 its own, be it directly a primary template or indirectly through a
415 partial specializations. */
416 static bool
418 {
430 /* So now we know we have a specialization, but it could be a full
431 or a partial specialization. To tell which, compare the depth of
432 its template arguments with those of its context. */
441 }
443 /* Subroutine of maybe_begin_member_template_processing.
444 Returns true if processing DECL needs us to push template parms. */
446 static bool
448 {
454 }
456 /* Subroutine of maybe_begin_member_template_processing.
457 Push the template parms in PARMS, starting from LEVELS steps into the
458 chain, and ending at the beginning, since template parms are listed
459 innermost first. */
461 static void
463 {
471 current_template_parms
479 NULL);
481 {
490 {
497 /* Push the CONST_DECL. */
503 }
504 }
505 }
507 /* Restore the template parameter context for a member template, a
508 friend template defined in a class definition, or a non-template
509 member of template class. */
511 void
513 {
514 tree parms;
519 {
522 /* Disregard full specializations (c++/60999). */
525 }
528 {
533 {
536 }
539 }
541 /* Remember how many levels of template parameters we pushed so that
542 we can pop them later. */
544 }
546 /* Undo the effects of maybe_begin_member_template_processing. */
548 void
550 {
559 {
563 }
564 }
566 /* Return a new template argument vector which contains all of ARGS,
567 but has as its innermost set of arguments the EXTRA_ARGS. */
569 tree
571 {
572 tree new_args;
590 }
592 /* Like add_to_template_args, but only the outermost ARGS are added to
593 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
594 (EXTRA_ARGS) levels are added. This function is used to combine
595 the template arguments from a partial instantiation with the
596 template arguments used to attain the full instantiation from the
597 partial instantiation.
599 If ARGS is a TEMPLATE_DECL, use its parameters as args. */
601 tree
603 {
604 tree new_args;
609 {
612 }
614 /* If there are more levels of EXTRA_ARGS than there are ARGS,
615 something very fishy is going on. */
618 /* If *all* the new arguments will be the EXTRA_ARGS, just return
619 them. */
623 /* For the moment, we make ARGS look like it contains fewer levels. */
628 /* Now, we restore ARGS to its full dimensions. */
632 }
634 /* Return the N levels of innermost template arguments from the ARGS. */
636 tree
638 {
639 tree new_args;
645 /* If N is 1, just return the innermost set of template arguments. */
649 /* If we're not removing anything, just return the arguments we were
650 given. */
656 /* Make a new set of arguments, not containing the outer arguments. */
663 }
665 /* The inverse of get_innermost_template_args: Return all but the innermost
666 EXTRA_LEVELS levels of template arguments from the ARGS. */
668 static tree
670 {
671 tree new_args;
677 /* If N is 1, just return the outermost set of template arguments. */
681 /* If we're not removing anything, just return the arguments we were
682 given. */
687 /* Make a new set of arguments, not containing the inner arguments. */
694 }
696 /* We've got a template header coming up; push to a new level for storing
697 the parms. */
699 void
701 {
702 /* We use a non-tag-transparent scope here, which causes pushtag to
703 put tags in this scope, rather than in the enclosing class or
704 namespace scope. This is the right thing, since we want
705 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
706 global template class, push_template_decl handles putting the
707 TEMPLATE_DECL into top-level scope. For a nested template class,
708 e.g.:
710 template <class T> struct S1 {
711 template <class T> struct S2 {};
712 };
714 pushtag contains special code to insert the TEMPLATE_DECL for S2
715 at the right scope. */
721 /* Add a dummy parameter level while we process the parameter list. */
722 current_template_parms
725 current_template_parms);
726 }
728 /* This routine is called when a specialization is declared. If it is
729 invalid to declare a specialization here, an error is reported and
730 false is returned, otherwise this routine will return true. */
732 static bool
734 {
737 /* [temp.expl.spec]
739 An explicit specialization shall be declared in the namespace of
740 which the template is a member, or, for member templates, in the
741 namespace of which the enclosing class or enclosing class
742 template is a member. An explicit specialization of a member
743 function, member class or static data member of a class template
744 shall be declared in the namespace of which the class template
745 is a member. */
747 {
750 }
752 /* [temp.expl.spec]
754 In an explicit specialization declaration for a member of a class
755 template or a member template that appears in namespace scope,
756 the member template and some of its enclosing class templates may
757 remain unspecialized, except that the declaration shall not
758 explicitly specialize a class member template if its enclosing
759 class templates are not explicitly specialized as well. */
761 {
764 }
767 }
769 /* We've just seen template <>. */
771 bool
773 {
777 }
779 /* Called at then end of processing a declaration preceded by
780 template<>. */
782 void
784 {
787 }
789 /* Any template <>'s that we have seen thus far are not referring to a
790 function specialization. */
792 void
794 {
797 }
799 /* We've just seen a template header. If SPECIALIZATION is nonzero,
800 it was of the form template <>. */
802 static void
804 {
806 template_header_count++;
807 }
809 /* We're beginning an explicit instantiation. */
811 void
813 {
816 }
819 void
821 {
824 }
826 /* An explicit specialization or partial specialization of TMPL is being
827 declared. Check that the namespace in which the specialization is
828 occurring is permissible. Returns false iff it is invalid to
829 specialize TMPL in the current namespace. */
831 static bool
833 {
836 /* [tmpl.expl.spec]
838 An explicit specialization shall be declared in a namespace enclosing the
839 specialized template. An explicit specialization whose declarator-id is
840 not qualified shall be declared in the nearest enclosing namespace of the
841 template, or, if the namespace is inline (7.3.1), any namespace from its
842 enclosing namespace set. */
845 {
848 }
851 /* Same or enclosing namespace. */
853 else
854 {
855 auto_diagnostic_group d;
861 }
862 }
864 /* SPEC is an explicit instantiation. Check that it is valid to
865 perform this explicit instantiation in the current namespace. */
867 static void
869 {
870 tree ns;
872 /* DR 275: An explicit instantiation shall appear in an enclosing
873 namespace of its template. */
879 }
881 /* Returns true if TYPE is a new partial specialization that needs to be
882 set up. This may also modify TYPE to point to the correct (new or
883 existing) constrained partial specialization. */
885 static bool
887 {
888 /* An implicit instantiation of an incomplete type implies
889 the definition of a new class template.
891 template<typename T>
892 struct S;
894 template<typename T>
895 struct S<T*>;
897 Here, S<T*> is an implicit instantiation of S whose type
898 is incomplete. */
902 /* It can also be the case that TYPE is a completed specialization.
903 Continuing the previous example, suppose we also declare:
905 template<typename T>
906 requires Integral<T>
907 struct S<T*>;
909 Here, S<T*> refers to the specialization S<T*> defined
910 above. However, we need to differentiate definitions because
911 we intend to define a new partial specialization. In this case,
912 we rely on the fact that the constraints are different for
913 this declaration than that above.
915 Note that we also get here for injected class names and
916 late-parsed template definitions. We must ensure that we
917 do not create new type declarations for those cases. */
919 {
923 /* If there are no template parameters, this cannot be a new
924 partial template specialization? */
928 /* The injected-class-name is not a new partial specialization. */
932 /* If the constraints are not the same as those of the primary
933 then, we can probably create a new specialization. */
937 {
941 }
943 /* Also, if there's a pre-existing specialization with matching
944 constraints, then this also isn't new. */
947 {
953 {
956 }
958 }
960 /* Create a new type node (and corresponding type decl)
961 for the newly declared specialization. */
966 /* We only need a separate type node for storing the definition of this
967 partial specialization; uses of S<T*> are unconstrained, so all are
968 equivalent. So keep TYPE_CANONICAL the same. */
971 /* Build the corresponding type decl. */
983 }
986 }
988 /* The TYPE is being declared. If it is a template type, that means it
989 is a partial specialization. Do appropriate error-checking. */
991 tree
993 {
994 tree context;
999 /* A lambda that appears in specialization context is not itself a
1000 specialization. */
1004 /* An injected-class-name is not a specialization. */
1009 {
1013 }
1018 {
1024 else
1027 }
1029 {
1030 /* This is for ordinary explicit specialization and partial
1031 specialization of a template class such as:
1033 template <> class C<int>;
1035 or:
1037 template <class T> class C<T*>;
1039 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
1042 {
1049 {
1054 }
1055 }
1061 /* Trying to define a specialization either without a template<> header
1062 or in an inappropriate place. We've already given an error, so just
1063 bail now so we don't actually define the specialization. */
1065 }
1071 {
1072 /* This is for an explicit specialization of member class
1073 template according to [temp.expl.spec/18]:
1075 template <> template <class U> class C<int>::D;
1077 The context `C<int>' must be an implicit instantiation.
1078 Otherwise this is just a member class template declared
1079 earlier like:
1081 template <> class C<int> { template <class U> class D; };
1082 template <> template <class U> class C<int>::D;
1084 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1085 while in the second case, `C<int>::D' is a primary template
1086 and `C<T>::D' may not exist. */
1090 {
1091 tree t;
1096 {
1099 type))
1102 }
1104 /* Check for invalid specialization after instantiation:
1106 template <> template <> class C<int>::D<int>;
1107 template <> template <class U> class C<int>::D; */
1111 {
1115 {
1116 /* We already have a full specialization of this partial
1117 instantiation, or a full specialization has been
1118 looked up but not instantiated. Reassign it to the
1119 new member specialization template. */
1120 spec_entry elt;
1133 spec_entry **slot
1138 }
1139 else
1140 /* But if we've had an implicit instantiation, that's a
1141 problem ([temp.expl.spec]/6). */
1144 }
1146 /* Mark TYPE as a specialization. And as a result, we only
1147 have one level of template argument for the innermost
1148 class template. */
1153 }
1154 }
1156 {
1157 /* Someday C++0x may allow for enum template specialization. */
1162 else
1163 {
1166 }
1167 }
1170 }
1172 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1173 gone through coerce_template_parms by now. */
1175 static void
1177 {
1179 {
1188 /* Allow typedefs on the type of a non-type argument, since a
1190 else
1192 }
1193 }
1195 static void
1197 {
1202 }
1204 /* Retrieve the specialization (in the sense of [temp.spec] - a
1205 specialization is either an instantiation or an explicit
1206 specialization) of TMPL for the given template ARGS. If there is
1207 no such specialization, return NULL_TREE. The ARGS are a vector of
1208 arguments, or a vector of vectors of arguments, in the case of
1209 templates with more than one level of parameters.
1211 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1212 then we search for a partial specialization matching ARGS. This
1213 parameter is ignored if TMPL is not a class template.
1215 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1216 result is a NONTYPE_ARGUMENT_PACK. */
1218 static tree
1220 {
1230 /* There should be as many levels of arguments as there are
1231 levels of parameters. */
1240 /* Lambda functions in templates aren't instantiated normally, but through
1241 tsubst_lambda_expr. */
1245 spec_entry elt;
1253 else
1262 }
1264 /* Like retrieve_specialization, but for local declarations. */
1266 tree
1268 {
1274 }
1276 /* Returns nonzero iff DECL is a specialization of TMPL. */
1278 int
1280 {
1281 tree t;
1284 {
1290 }
1291 else
1292 {
1301 }
1304 }
1306 /* Returns nonzero iff DECL is a specialization of friend declaration
1307 FRIEND_DECL according to [temp.friend]. */
1309 bool
1311 {
1318 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1319 of a template class, we want to check if DECL is a specialization
1320 if this. */
1325 {
1326 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1329 }
1334 /* There is nothing to do if this is not a template friend. */
1341 /* [temp.friend/6]
1342 A member of a class template may be declared to be a friend of a
1343 non-template class. In this case, the corresponding member of
1344 every specialization of the class template is a friend of the
1345 class granting friendship.
1347 For example, given a template friend declaration
1349 template <class T> friend void A<T>::f();
1351 the member function below is considered a friend
1353 template <> struct A<int> {
1354 void f();
1355 };
1357 For this type of template friend, TEMPLATE_DEPTH below will be
1358 nonzero. To determine if DECL is a friend of FRIEND, we first
1359 check if the enclosing class is a specialization of another. */
1366 {
1367 /* Next, we check the members themselves. In order to handle
1368 a few tricky cases, such as when FRIEND_DECL's are
1370 template <class T> friend void A<T>::g(T t);
1371 template <class T> template <T t> friend void A<T>::h();
1373 and DECL's are
1375 void A<int>::g(int);
1376 template <int> void A<int>::h();
1378 we need to figure out ARGS, the template arguments from
1379 the context of DECL. This is required for template substitution
1380 of `T' in the function parameter of `g' and template parameter
1381 of `h' in the above examples. Here ARGS corresponds to `int'. */
1388 {
1390 {
1393 else
1395 current_depth++;
1396 }
1398 }
1401 {
1403 tree friend_type;
1404 tree decl_type;
1405 tree friend_args_type;
1406 tree decl_args_type;
1408 /* Make sure that both DECL and FRIEND_DECL are templates or
1409 non-templates. */
1415 {
1416 /* If both are templates, check template parameter list. */
1417 tree friend_parms
1422 friend_parms))
1426 }
1427 else
1435 /* Check if return types match. */
1439 /* Check if function parameter types match, ignoring the
1440 `this' parameter. */
1449 }
1450 else
1451 {
1452 /* DECL is a TYPE_DECL */
1456 /* Make sure that both DECL and FRIEND_DECL are templates or
1457 non-templates. */
1458 is_template
1465 {
1466 tree friend_parms;
1467 /* If both are templates, check the name of the two
1468 TEMPLATE_DECL's first because is_friend didn't. */
1473 /* Now check template parameter list. */
1474 friend_parms
1477 return comp_template_parms
1479 friend_parms);
1480 }
1481 else
1484 }
1485 }
1487 }
1489 /* Register the specialization SPEC as a specialization of TMPL with
1490 the indicated ARGS. IS_FRIEND indicates whether the specialization
1491 is actually just a friend declaration. ATTRLIST is the list of
1492 attributes that the specialization is declared with or NULL when
1493 it isn't. Returns SPEC, or an equivalent prior declaration, if
1494 available.
1496 We also store instantiations of field packs in the hash table, even
1497 though they are not themselves templates, to make lookup easier. */
1499 static tree
1501 hashval_t hash)
1502 {
1503 tree fn;
1511 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1512 register it; we want the corresponding TEMPLATE_DECL instead.
1513 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1514 the more obvious `uses_template_parms (spec)' to avoid problems
1515 with default function arguments. In particular, given
1516 something like this:
1518 template <class T> void f(T t1, T t = T())
1520 the default argument expression is not substituted for in an
1521 instantiation unless and until it is actually needed. */
1524 spec_entry elt;
1535 else
1538 /* We can sometimes try to re-register a specialization that we've
1539 already got. In particular, regenerate_decl_from_template calls
1540 duplicate_decls which will update the specialization list. But,
1541 we'll still get called again here anyhow. It's more convenient
1542 to simply allow this than to try to prevent it. */
1546 {
1548 {
1551 {
1553 fn);
1555 }
1556 else
1557 {
1558 tree clone;
1559 /* This situation should occur only if the first
1560 specialization is an implicit instantiation, the
1561 second is an explicit specialization, and the
1562 implicit instantiation has not yet been used. That
1563 situation can occur if we have implicitly
1564 instantiated a member function and then specialized
1565 it later.
1567 We can also wind up here if a friend declaration that
1568 looked like an instantiation turns out to be a
1569 specialization:
1571 template <class T> void foo(T);
1572 class S { friend void foo<>(int) };
1573 template <> void foo(int);
1575 We transform the existing DECL in place so that any
1576 pointers to it become pointers to the updated
1577 declaration.
1579 If there was a definition for the template, but not
1580 for the specialization, we want this to look as if
1581 there were no definition, and vice versa. */
1585 /* The call to duplicate_decls will have applied
1586 [temp.expl.spec]:
1588 An explicit specialization of a function template
1589 is inline only if it is explicitly declared to be,
1590 and independently of whether its function template
1591 is.
1593 to the primary function; now copy the inline bits to
1594 the various clones. */
1596 {
1603 }
1607 }
1608 }
1610 {
1613 /* We've already complained in duplicate_decls. */
1617 /* Dup decl failed, but this is a new definition. Set the
1618 line number so any errors match this new
1619 definition. */
1623 }
1624 }
1628 /* A specialization must be declared in the same namespace as the
1629 template it is specializing. */
1642 /* If TMPL is a forward declaration of a template function, keep a list
1643 of all specializations in case we need to reassign them to a friend
1644 template later in tsubst_friend_function.
1646 Also keep a list of all variable template instantiations so that
1647 process_partial_specialization can check whether a later partial
1648 specialization would have used it. */
1653 }
1655 /* Restricts tree and type comparisons. */
1659 /* Returns true iff two spec_entry nodes are equivalent. */
1661 bool
1663 {
1672 /* tmpl could be a FIELD_DECL for a capture pack. */
1676 {
1677 /* Partial specializations of a variable template can be distinguished by
1678 constraints. */
1682 }
1688 }
1690 /* Returns a hash for a template TMPL and template arguments ARGS. */
1692 static hashval_t
1694 {
1697 }
1699 hashval_t
1701 {
1706 }
1708 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1709 ignoring SPEC. */
1711 hashval_t
1713 {
1715 }
1717 /* Recursively calculate a hash value for a template argument ARG, for use
1718 in the hash tables of template specializations. We must be
1719 careful to (at least) skip the same entities template_args_equal
1720 does. */
1722 hashval_t
1724 {
1729 /* Strip nop-like things, but not the same as STRIP_NOPS. */
1740 {
1742 /* Getting here with an ARGUMENT_PACK_SELECT means we're probably
1743 preserving it in a hash table, which is bad because it will change
1744 meaning when gen_elem_of_pack_expansion_instantiation changes the
1745 ARGUMENT_PACK_SELECT_INDEX. */
1779 {
1782 {
1785 }
1787 }
1791 {
1794 }
1805 val = iterative_hash_template_arg
1817 val);
1819 val);
1828 /* [temp.over.link] Two lambda-expressions are never considered
1829 equivalent.
1831 So just hash the closure type. */
1842 /* Now hash operands as usual. */
1846 {
1849 {
1853 }
1855 call_expr_arg_iterator ai;
1860 }
1864 }
1868 {
1871 {
1872 // We want an alias specialization that survived strip_typedefs
1873 // to hash differently from its TYPE_CANONICAL, to avoid hash
1874 // collisions that compare as different in template_args_equal.
1875 // These could be dependent specializations that strip_typedefs
1876 // left alone, or untouched specializations because
1877 // coerce_template_parms returns the unconverted template
1878 // arguments if it sees incomplete argument packs.
1881 }
1884 {
1891 {
1892 /* Hash the components that are relevant to TYPENAME_TYPE
1893 equivalence as determined by structural_comptypes. We
1894 can only coherently do this when comparing_specializations
1895 is set, because otherwise structural_comptypes tries
1896 resolving TYPENAME_TYPE via the current instantiation. */
1901 }
1908 }
1921 }
1922 }
1924 /* Unregister the specialization SPEC as a specialization of TMPL.
1925 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1926 if the SPEC was listed as a specialization of TMPL.
1928 Note that SPEC has been ggc_freed, so we can't look inside it. */
1930 bool
1932 {
1934 spec_entry elt;
1942 {
1947 }
1950 }
1952 /* Like register_specialization, but for local declarations. We are
1953 registering SPEC, an instantiation of TMPL. */
1955 void
1957 {
1960 }
1962 /* Registers T as a specialization of itself. This is used to preserve
1963 the references to already-parsed parameters when instantiating
1964 postconditions. */
1966 void
1968 {
1970 }
1972 /* TYPE is a class type. Returns true if TYPE is an explicitly
1973 specialized class. */
1975 bool
1977 {
1981 }
1983 /* Print the list of functions at FNS, going through all the overloads
1984 for each element of the list. Alternatively, FNS cannot be a
1985 TREE_LIST, in which case it will be printed together with all the
1986 overloads.
1988 MORE and *STR should respectively be FALSE and NULL when the function
1989 is called from the outside. They are used internally on recursive
1990 calls. print_candidates manages the two parameters and leaves NULL
1991 in *STR when it ends. */
1993 static void
1995 {
1999 else
2001 {
2007 {
2010 else
2013 }
2015 }
2016 }
2018 /* Print the list of candidate FNS in an error message. FNS can also
2019 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
2021 void
2023 {
2027 }
2029 /* Get a (possibly) constrained template declaration for the
2030 purpose of ordering candidates. */
2031 static tree
2033 {
2039 }
2041 /* Among candidates having the same signature, return the
2042 most constrained or NULL_TREE if there is no best candidate.
2043 If the signatures of candidates vary (e.g., template
2044 specialization vs. member function), then there can be no
2045 most constrained.
2047 Note that we don't compare constraints on the functions
2048 themselves, but rather those of their templates. */
2049 static tree
2051 {
2052 // Try to find the best candidate in a first pass.
2055 {
2062 }
2064 // Verify that the champ is better than previous candidates.
2069 }
2072 }
2075 /* Returns the template (one of the functions given by TEMPLATE_ID)
2076 which can be specialized to match the indicated DECL with the
2077 explicit template args given in TEMPLATE_ID. The DECL may be
2078 NULL_TREE if none is available. In that case, the functions in
2079 TEMPLATE_ID are non-members.
2081 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2082 specialization of a member template.
2084 The TEMPLATE_COUNT is the number of references to qualifying
2085 template classes that appeared in the name of the function. See
2086 check_explicit_specialization for a more accurate description.
2088 TSK indicates what kind of template declaration (if any) is being
2089 declared. TSK_TEMPLATE indicates that the declaration given by
2090 DECL, though a FUNCTION_DECL, has template parameters, and is
2091 therefore a template function.
2093 The template args (those explicitly specified and those deduced)
2094 are output in a newly created vector *TARGS_OUT.
2096 If it is impossible to determine the result, an error message is
2097 issued. The error_mark_node is returned to indicate failure. */
2099 static tree
2101 tree decl,
2105 tmpl_spec_kind tsk)
2106 {
2107 tree fns;
2108 tree targs;
2109 tree explicit_targs;
2112 /* A TREE_LIST of templates of which DECL may be a specialization.
2113 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2114 corresponding TREE_PURPOSE is the set of template arguments that,
2115 when used to instantiate the template, would produce a function
2116 with the signature of DECL. */
2126 /* We shouldn't be specializing a member template of an
2127 unspecialized class template; we already gave an error in
2128 check_specialization_scope, now avoid crashing. */
2132 {
2135 }
2143 /* Check for baselinks. */
2148 {
2152 }
2154 {
2157 }
2159 /* Count the number of template headers specified for this
2160 specialization. */
2171 {
2174 tf_warning_or_error);
2178 }
2180 {
2184 {
2185 tree decl_arg_types;
2186 tree fn_arg_types;
2188 /* In case of explicit specialization, we need to check if
2189 the number of template headers appearing in the specialization
2190 is correct. This is usually done in check_explicit_specialization,
2191 but the check done there cannot be exhaustive when specializing
2192 member functions. Consider the following code:
2194 template <> void A<int>::f(int);
2195 template <> template <> void A<int>::f(int);
2197 Assuming that A<int> is not itself an explicit specialization
2198 already, the first line specializes "f" which is a non-template
2199 member function, whilst the second line specializes "f" which
2200 is a template member function. So both lines are syntactically
2201 correct, and check_explicit_specialization does not reject
2202 them.
2204 Here, we can do better, as we are matching the specialization
2205 against the declarations. We count the number of template
2206 headers, and we check if they match TEMPLATE_COUNT + 1
2207 (TEMPLATE_COUNT is the number of qualifying template classes,
2208 plus there must be another header for the member template
2209 itself).
2211 Notice that if header_count is zero, this is not a
2212 specialization but rather a template instantiation, so there
2213 is no check we can perform here. */
2215 {
2218 }
2220 /* Check that the number of template arguments at the
2221 innermost level for DECL is the same as for FN. */
2229 /* DECL might be a specialization of FN. */
2233 /* For a non-static member function, we need to make sure
2234 that the const qualification is the same. Since
2235 get_bindings does not try to merge the "this" parameter,
2236 we must do the comparison explicitly. */
2238 {
2243 /* And the ref-qualification. */
2247 }
2249 /* Skip the "this" parameter and, for constructors of
2250 classes with virtual bases, the VTT parameter. A
2251 full specialization of a constructor will have a VTT
2252 parameter, but a template never will. */
2253 decl_arg_types
2255 fn_arg_types
2258 /* Function templates cannot be specializations; there are
2259 no partial specializations of functions. Therefore, if
2260 the type of DECL does not match FN, there is no
2261 match.
2263 Note that it should never be the case that we have both
2264 candidates added here, and for regular member functions
2265 below. */
2267 {
2269 current_template_parms))
2282 {
2283 /* C++20 CA104: Substitute directly into the
2284 constraint-expression. */
2290 }
2294 }
2296 /* See whether this function might be a specialization of this
2297 template. Suppress access control because we might be trying
2298 to make this specialization a friend, and we have already done
2299 access control for the declaration of the specialization. */
2305 /* We cannot deduce template arguments that when used to
2306 specialize TMPL will produce DECL. */
2310 /* We deduced something involving 'auto', which isn't a valid
2311 template argument. */
2314 /* Save this template, and the arguments deduced. */
2316 }
2318 /* FN is an ordinary member function, and we need a
2319 specialization of a member template. */
2320 ;
2322 /* We can get IDENTIFIER_NODEs here in certain erroneous
2323 cases. */
2324 ;
2326 /* This is just an ordinary non-member function. Nothing can
2327 be a specialization of that. */
2328 ;
2330 /* Cannot specialize functions that are created implicitly. */
2331 ;
2332 else
2333 {
2334 tree decl_arg_types;
2336 /* This is an ordinary member function. However, since
2337 we're here, we can assume its enclosing class is a
2338 template class. For example,
2340 template <typename T> struct S { void f(); };
2341 template <> void S<int>::f() {}
2343 Here, S<int>::f is a non-template, but S<int> is a
2344 template class. If FN has the same type as DECL, we
2345 might be in business. */
2348 /* Its enclosing class is an explicit specialization
2349 of a template class. This is not a candidate. */
2354 /* The return types differ. */
2357 /* Adjust the type of DECL in case FN is a static member. */
2364 decl_arg_types))
2372 // If the deduced arguments do not satisfy the constraints,
2373 // this is not a candidate.
2377 // Add the candidate.
2379 }
2380 }
2383 {
2384 /* We have:
2386 [temp.expl.spec]
2388 It is possible for a specialization with a given function
2389 signature to be instantiated from more than one function
2390 template. In such cases, explicit specification of the
2391 template arguments must be used to uniquely identify the
2392 function template specialization being specialized.
2394 Note that here, there's no suggestion that we're supposed to
2395 determine which of the candidate templates is most
2396 specialized. However, we, also have:
2398 [temp.func.order]
2400 Partial ordering of overloaded function template
2401 declarations is used in the following contexts to select
2402 the function template to which a function template
2403 specialization refers:
2405 -- when an explicit specialization refers to a function
2406 template.
2408 So, we do use the partial ordering rules, at least for now.
2409 This extension can only serve to make invalid programs valid,
2410 so it's safe. And, there is strong anecdotal evidence that
2411 the committee intended the partial ordering rules to apply;
2412 the EDG front end has that behavior, and John Spicer claims
2413 that the committee simply forgot to delete the wording in
2414 [temp.expl.spec]. */
2417 {
2420 }
2421 }
2423 // Concepts allows multiple declarations of member functions
2424 // with the same signature. Like above, we need to rely on
2425 // on the partial ordering of those candidates to determine which
2426 // is the best.
2428 {
2430 {
2433 }
2434 }
2437 {
2442 "saw %d %<template<>%>, need %d for "
2447 }
2451 {
2457 }
2459 /* We have one, and exactly one, match. */
2461 {
2465 /* Propagate the candidate's constraints to the declaration. */
2469 /* DECL is a re-declaration or partial instantiation of a template
2470 function. */
2473 /* It was a specialization of an ordinary member function in a
2474 template class. */
2476 }
2478 /* It was a specialization of a template. */
2482 /* Propagate the template's constraints to the declaration. */
2487 }
2489 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2490 but with the default argument values filled in from those in the
2491 TMPL_TYPES. */
2493 static tree
2495 tree tmpl_types)
2496 {
2497 tree new_spec_types;
2505 /* Substitute into the rest of the list. */
2506 new_spec_types =
2510 /* Add the default argument for this parameter. */
2513 new_spec_types);
2514 }
2516 /* DECL is an explicit specialization. Replicate default arguments
2517 from the template it specializes. (That way, code like:
2519 template <class T> void f(T = 3);
2520 template <> void f(double);
2521 void g () { f (); }
2523 works, as required.) An alternative approach would be to look up
2524 the correct default arguments at the call-site, but this approach
2525 is consistent with how implicit instantiations are handled. */
2527 static void
2529 {
2530 tree tmpl;
2531 tree spec_types;
2532 tree tmpl_types;
2533 tree new_spec_types;
2534 tree old_type;
2535 tree new_type;
2536 tree t;
2541 /* See if there's anything we need to do. */
2554 {
2555 /* Remove the this pointer, but remember the object's type for
2556 CV quals. */
2562 {
2563 /* DECL may contain more parameters than TMPL due to the extra
2564 in-charge parameter in constructors and destructors. */
2567 }
2569 {
2572 }
2573 }
2575 /* Compute the merged default arguments. */
2576 new_spec_types =
2579 /* Compute the new FUNCTION_TYPE. */
2581 {
2585 new_spec_types);
2588 /* Put the in-charge parameter back. */
2591 new_spec_types);
2595 new_spec_types);
2596 }
2597 else
2599 new_spec_types);
2605 }
2607 /* Return the number of template headers we expect to see for a definition
2608 or specialization of CTYPE or one of its non-template members. */
2610 int
2612 {
2616 {
2617 /* You're supposed to have one `template <...>' for every
2618 template class, but you don't need one for a full
2619 specialization. For example:
2621 template <class T> struct S{};
2622 template <> struct S<int> { void f(); };
2623 void S<int>::f () {}
2625 is correct; there shouldn't be a `template <>' for the
2626 definition of `S<int>::f'. */
2628 /* If CTYPE does not have template information of any
2629 kind, then it is not a template, nor is it nested
2630 within a template. */
2638 }
2641 }
2643 /* Do a simple sanity check on the template headers that precede the
2644 variable declaration DECL. */
2646 void
2648 {
2653 {
2656 "variable templates only available with "
2659 // Namespace-scope variable templates should have a template header.
2661 }
2663 {
2664 auto_diagnostic_group d;
2666 "too many template headers for %qD "
2672 "members of an explicitly specialized class are defined "
2674 }
2675 }
2677 /* An explicit specialization whose declarator-id or class-head-name is not
2678 qualified shall be declared in the nearest enclosing namespace of the
2679 template, or, if the namespace is inline (7.3.1), any namespace from its
2680 enclosing namespace set.
2682 If the name declared in the explicit instantiation is an unqualified name,
2683 the explicit instantiation shall appear in the namespace where its template
2684 is declared or, if that namespace is inline (7.3.1), any namespace from its
2685 enclosing namespace set. */
2687 void
2689 {
2694 {
2700 /* This was allowed in C++98, so only pedwarn. */
2702 "outside its namespace must use a nested-name-"
2704 }
2705 }
2707 /* Warn for a template specialization SPEC that is missing some of a set
2708 of function or type attributes that the template TEMPL is declared with.
2709 ATTRLIST is a list of additional attributes that SPEC should be taken
2710 to ultimately be declared with. */
2712 static void
2714 {
2718 /* Avoid warning if the difference between the primary and
2719 the specialization is not in one of the attributes below. */
2723 };
2725 /* Put together a list of the black listed attributes that the primary
2726 template is declared with that the specialization is not, in case
2727 it's not apparent from the most recent declaration of the primary. */
2728 pretty_printer str;
2735 auto_diagnostic_group d;
2738 spec))
2744 }
2746 /* Check to see if the function just declared, as indicated in
2747 DECLARATOR, and in DECL, is a specialization of a function
2748 template. We may also discover that the declaration is an explicit
2749 instantiation at this point.
2751 Returns DECL, or an equivalent declaration that should be used
2752 instead if all goes well. Issues an error message if something is
2753 amiss. Returns error_mark_node if the error is not easily
2754 recoverable.
2756 FLAGS is a bitmask consisting of the following flags:
2758 2: The function has a definition.
2759 4: The function is a friend.
2761 The TEMPLATE_COUNT is the number of references to qualifying
2762 template classes that appeared in the name of the function. For
2763 example, in
2765 template <class T> struct S { void f(); };
2766 void S<int>::f();
2768 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2769 classes are not counted in the TEMPLATE_COUNT, so that in
2771 template <class T> struct S {};
2772 template <> struct S<int> { void f(); }
2773 template <> void S<int>::f();
2775 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2776 invalid; there should be no template <>.)
2778 If the function is a specialization, it is marked as such via
2779 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2780 is set up correctly, and it is added to the list of specializations
2781 for that template. */
2783 tree
2785 tree decl,
2788 tree attrlist)
2789 {
2798 tmpl_spec_kind tsk;
2801 {
2804 else
2806 }
2807 else
2811 {
2814 {
2817 }
2821 {
2823 /* This could be something like:
2825 template <class T> void f(T);
2826 class S { friend void f<>(int); } */
2828 else
2829 {
2830 /* This case handles bogus declarations like template <>
2831 template <class T> void f<int>(); */
2835 declarator);
2837 }
2838 }
2842 /* The error has already been reported in
2843 check_specialization_scope. */
2849 /* Fall through. */
2862 decl);
2865 else
2869 /* Fall through. */
2875 /* In cases like template<> constexpr bool v = true;
2876 We'll give an error in check_template_variable. */
2882 else
2888 {
2889 /* This case handles bogus declarations like template <>
2890 template <class T> void f<int>(); */
2895 declarator);
2897 {
2898 /* Partial specialization of variable template. */
2902 }
2905 "non-type partial specialization %qE "
2907 else
2909 "non-class, non-variable partial specialization %qE "
2912 ok:;
2913 }
2916 /* This is a specialization of a member template, without
2917 specialization the containing class. Something like:
2919 template <class T> struct S {
2920 template <class U> void f (U);
2921 };
2922 template <> template <class U> void S<int>::f(U) {}
2924 That's a specialization -- but of the entire template. */
2930 }
2933 /* This doesn't apply to variable templates. */
2935 {
2939 {
2943 }
2944 }
2947 {
2953 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2955 {
2956 tree fns;
2961 else
2962 {
2963 /* If there is no class context, the explicit instantiation
2964 must be at namespace scope. */
2967 /* Find the namespace binding, using the declaration
2968 context. */
2972 {
2973 /* If lookup fails, look for a friend declaration so we can
2974 give a better diagnostic. */
2975 fns = (lookup_qualified_name
2980 }
2983 {
2986 }
2987 }
2990 }
2996 {
2998 /* A specialization in class scope. This is invalid,
2999 but the error will already have been flagged by
3000 check_specialization_scope. */
3002 else
3003 {
3004 /* It's not valid to write an explicit instantiation in
3005 class scope, e.g.:
3007 class C { template void f(); }
3009 This case is caught by the parser. However, on
3010 something like:
3012 template class C { void f(); };
3014 (which is invalid) we can get here. The error will be
3015 issued later. */
3016 ;
3017 }
3020 }
3023 {
3024 // We'll match variable templates in start_decl.
3028 /* Find the list of functions in ctype that have the same
3029 name as the declared function. */
3033 {
3037 {
3038 /* From [temp.expl.spec]:
3040 If such an explicit specialization for the member
3041 of a class template names an implicitly-declared
3042 special member function (clause _special_), the
3043 program is ill-formed.
3045 Similar language is found in [temp.explicit]. */
3048 }
3051 }
3053 /* For a type-conversion operator, We might be looking for
3054 `operator int' which will be a specialization of
3055 `operator T'. Grab all the conversion operators, and
3056 then select from them. */
3061 {
3064 }
3065 else
3067 }
3069 /* Figure out what exactly is being specialized at this point.
3070 Note that for an explicit instantiation, even one for a
3071 member function, we cannot tell a priori whether the
3072 instantiation is for a member template, or just a member
3073 function of a template class. Even if a member template is
3074 being instantiated, the member template arguments may be
3075 elided if they can be deduced from the rest of the
3076 declaration. */
3079 member_specialization,
3080 template_count,
3081 tsk);
3084 /* We couldn't figure out what this declaration was
3085 specializing. */
3087 else
3088 {
3090 {
3091 auto_diagnostic_group d;
3093 "friend declaration %qD is not visible to "
3097 }
3106 {
3107 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3108 is done by do_decl_instantiation later. */
3114 {
3115 /* If TMPL is not the most general template (for
3116 example, if TMPL is a friend template that is
3117 injected into namespace scope), then there will
3118 be too many levels of TARGS. Remove some of them
3119 here. */
3121 tree new_targs;
3128 }
3131 }
3133 /* If we thought that the DECL was a member function, but it
3134 turns out to be specializing a static member function,
3135 make DECL a static member function as well. */
3141 /* If this is a specialization of a member template of a
3142 template class, we want to return the TEMPLATE_DECL, not
3143 the specialization of it. */
3145 {
3150 {
3151 tree parm;
3155 /* We want to use the argument list specified in the
3156 definition, not in the original declaration. */
3161 }
3166 }
3168 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3174 /* Inherit default function arguments from the template
3175 DECL is specializing. */
3179 /* This specialization has the same protection as the
3180 template it specializes. */
3184 /* 7.1.1-1 [dcl.stc]
3186 A storage-class-specifier shall not be specified in an
3187 explicit specialization...
3189 The parser rejects these, so unless action is taken here,
3190 explicit function specializations will always appear with
3191 global linkage.
3193 The action recommended by the C++ CWG in response to C++
3194 defect report 605 is to make the storage class and linkage
3195 of the explicit specialization match the templated function:
3197 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3198 */
3200 {
3204 /* A concept cannot be specialized. */
3206 {
3208 gen_tmpl);
3210 }
3212 /* This specialization has the same linkage and visibility as
3213 the function template it specializes. */
3216 {
3219 }
3222 {
3225 }
3226 }
3228 /* If DECL is a friend declaration, declared using an
3229 unqualified name, the namespace associated with DECL may
3230 have been set incorrectly. For example, in:
3232 template <typename T> void f(T);
3233 namespace N {
3234 struct S { friend void f<int>(int); }
3235 }
3237 we will have set the DECL_CONTEXT for the friend
3238 declaration to N, rather than to the global namespace. */
3243 /* This is not really a declaration of a specialization.
3244 It's just the name of an instantiation. But, it's not
3245 a request for an instantiation, either. */
3248 /* A specialization is not necessarily COMDAT. */
3254 /* If this is a full specialization, register it so that we can find
3255 it again. Partial specializations will be registered in
3256 process_partial_specialization. */
3258 {
3263 }
3265 /* If this is a specialization, splice any contracts that may have
3266 been inherited from the template, removing them. */
3270 /* A 'structor should already have clones. */
3276 }
3277 }
3280 }
3282 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3283 parameters. These are represented in the same format used for
3284 DECL_TEMPLATE_PARMS. */
3286 int
3288 {
3289 const_tree p1;
3290 const_tree p2;
3298 {
3310 {
3314 /* If either of the template parameters are invalid, assume
3315 they match for the sake of error recovery. */
3328 }
3329 }
3332 /* One set of parameters has more parameters lists than the
3333 other. */
3337 }
3339 /* Returns true if two template parameters are declared with
3340 equivalent constraints. */
3342 static bool
3344 {
3352 }
3354 /* Returns true when two template parameters are equivalent. */
3356 static bool
3358 {
3362 /* If either of the template parameters are invalid, assume
3363 they match for the sake of error recovery. */
3367 /* ... they declare parameters of the same kind. */
3371 /* ... one parameter was introduced by a parameter declaration, then
3372 both are. This case arises as a result of eagerly rewriting declarations
3373 during parsing. */
3377 /* ... if either declares a pack, they both do. */
3382 {
3383 /* ... if they declare non-type parameters, the types are equivalent. */
3386 }
3388 {
3389 /* ... if they declare template template parameters, their template
3390 parameter lists are equivalent. */
3393 }
3395 /* ... if they are declared with a qualified-concept name, they both
3396 are, and those names are equivalent. */
3398 }
3400 /* Returns true if two template parameters lists are equivalent.
3401 Two template parameter lists are equivalent if they have the
3402 same length and their corresponding parameters are equivalent.
3404 PARMS1 and PARMS2 are TREE_LISTs containing TREE_VECs: the
3405 data structure returned by DECL_TEMPLATE_PARMS.
3407 This is generally the same implementation as comp_template_parms
3408 except that it also the concept names and arguments used to
3409 introduce parameters. */
3411 static bool
3413 {
3420 {
3428 {
3433 }
3437 }
3443 }
3445 /* Return true if the requires-clause of the template parameter lists are
3446 equivalent and false otherwise. */
3447 static bool
3449 {
3457 }
3459 /* Returns true if two template heads are equivalent. 17.6.6.1p6:
3460 Two template heads are equivalent if their template parameter
3461 lists are equivalent and their requires clauses are equivalent.
3463 In pre-C++20, this is equivalent to calling comp_template_parms
3464 for the template parameters of TMPL1 and TMPL2. */
3466 bool
3468 {
3472 /* Don't change the matching rules for pre-C++20. */
3476 /* ... have the same number of template parameters, and their
3477 corresponding parameters are equivalent. */
3481 /* ... if either has a requires-clause, they both do and their
3482 corresponding constraint-expressions are equivalent. */
3484 }
3486 /* Determine whether PARM is a parameter pack. */
3488 bool
3490 {
3491 /* Determine if we have a non-type template parameter pack. */
3498 /* If this is a list of template parameters, we could get a
3499 TYPE_DECL or a TEMPLATE_DECL. */
3503 /* Otherwise it must be a type template parameter. */
3507 }
3509 /* Determine if T is a function parameter pack. */
3511 bool
3513 {
3517 }
3519 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3520 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3522 tree
3524 {
3531 }
3533 /* Return true iff the function parameter PARAM_DECL was expanded
3534 from the function parameter pack PACK. */
3536 bool
3538 {
3543 /* The parameter pack and its pack arguments have the same
3544 DECL_PARM_INDEX. */
3546 }
3548 /* Determine whether ARGS describes a variadic template args list,
3549 i.e., one that is terminated by a template argument pack. */
3551 static bool
3553 {
3555 tree last_parm;
3569 }
3571 /* Generate a new name for the parameter pack name NAME (an
3572 IDENTIFIER_NODE) that incorporates its */
3574 static tree
3576 {
3577 /* Munge the name to include the parameter index. */
3578 #define NUMBUF_LEN 128
3592 }
3594 /* Return true if T is a primary function, class or alias template
3595 specialization, not including the template pattern. */
3597 bool
3599 {
3615 }
3617 /* Return true if PARM is a template template parameter. */
3619 bool
3621 {
3623 }
3625 /* Return true iff PARM is a DECL representing a type template
3626 parameter. */
3628 bool
3630 {
3635 }
3637 /* Return the template parameters of T if T is a
3638 primary template instantiation, NULL otherwise. */
3640 tree
3642 {
3647 parms = INNERMOST_TEMPLATE_PARMS
3651 }
3653 /* Returns the template arguments of T if T is a template instantiation,
3654 NULL otherwise. */
3656 tree
3658 {
3666 }
3668 /* Return the argument pack elements of T if T is a template argument pack,
3669 NULL otherwise. */
3671 tree
3673 {
3679 }
3681 /* In an ARGUMENT_PACK_SELECT, the actual underlying argument that the
3682 ARGUMENT_PACK_SELECT represents. */
3684 static tree
3686 {
3690 /* If the selected argument is an expansion E, that most likely means we were
3691 called from gen_elem_of_pack_expansion_instantiation during the
3692 substituting of an argument pack (of which the Ith element is a pack
3693 expansion, where I is ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
3694 In this case, the Ith element resulting from this substituting is going to
3695 be a pack expansion, which pattern is the pattern of E. Let's return the
3696 pattern of E, and gen_elem_of_pack_expansion_instantiation will build the
3697 resulting pack expansion from it. */
3699 {
3700 /* Make sure we aren't throwing away arg info. */
3703 }
3706 }
3708 /* Return a modification of ARGS that's suitable for preserving inside a hash
3709 table. In particular, this replaces each ARGUMENT_PACK_SELECT with its
3710 underlying argument. ARGS is copied (upon modification) iff COW_P. */
3712 static tree
3714 {
3719 {
3721 tree r;
3728 else
3731 {
3733 {
3736 }
3738 }
3739 }
3742 }
3744 /* True iff FN is a function representing a built-in variadic parameter
3745 pack. */
3747 bool
3749 {
3759 }
3761 /* True iff CALL is a call to a function representing a built-in variadic
3762 parameter pack. */
3764 static bool
3766 {
3770 }
3772 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3774 static tree
3776 tree in_decl)
3777 {
3782 {
3784 {
3787 }
3792 }
3793 else
3794 {
3799 /* Calculate the largest value of len that won't make the size of the vec
3800 overflow an int. The compiler will exceed resource limits long before
3801 this, but it seems a decent place to diagnose. */
3805 {
3809 max);
3811 }
3819 }
3820 }
3822 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3823 CALL. */
3825 static tree
3827 tree in_decl)
3828 {
3838 }
3840 /* Return true if the tree T has the extra args mechanism for
3841 avoiding partial instantiation. */
3843 static bool
3845 {
3850 }
3852 /* Structure used to track the progress of find_parameter_packs_r. */
3853 struct find_parameter_pack_data
3854 {
3855 /* TREE_LIST that will contain all of the parameter packs found by
3856 the traversal. */
3859 /* Set of AST nodes that have been visited by the traversal. */
3862 /* True iff we're making a type pack expansion. */
3865 /* True iff we found a subtree that has the extra args mechanism. */
3867 };
3869 /* Identifies all of the argument packs that occur in a template
3870 argument and appends them to the TREE_LIST inside DATA, which is a
3871 find_parameter_pack_data structure. This is a subroutine of
3872 make_pack_expansion and uses_parameter_packs. */
3873 static tree
3875 {
3881 #define WALK_SUBTREE(NODE) \
3882 cp_walk_tree (&(NODE), &find_parameter_packs_r, \
3883 ppd, ppd->visited) \
3885 /* Don't look through typedefs; we are interested in whether a
3886 parameter pack is actually written in the expression/type we're
3887 looking at, not the target type. */
3889 {
3890 /* But do look at arguments for an alias template. */
3897 }
3899 /* Identify whether this is a parameter pack or not. */
3901 {
3909 /* FALLTHRU */
3911 /* If the placeholder appears in the decl-specifier-seq of a function
3912 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3913 is a pack expansion, the invented template parameter is a template
3914 parameter pack. */
3924 {
3925 /* We don't want to walk into the type of a PARM_DECL,
3926 because we don't want to see the type parameter pack. */
3929 }
3934 {
3935 /* We don't want to walk into the type of a variadic capture proxy,
3936 because we don't want to see the type parameter pack. */
3939 }
3941 {
3943 find_parameter_packs_r,
3946 }
3958 /* Not a parameter pack. */
3960 }
3963 {
3964 /* Add this parameter pack to the list. */
3966 }
3975 /* This switch statement will return immediately if we don't find a
3976 parameter pack. ??? Should some of these be in cp_walk_subtrees? */
3978 {
3980 /* Check the template itself. */
3986 {
3988 /* Ignore the declaration of a capture proxy for a parameter pack. */
3992 /* Since we stop at typedefs above, we need to look through them at
3993 the point of the DECL_EXPR. */
3997 }
4024 {
4025 /* Since we defer implicit capture, look in the parms and body. */
4032 }
4035 {
4036 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
4037 type_pack_expansion_p to false so that any placeholders
4038 within the expression don't get marked as parameter packs. */
4046 }
4055 /* Don't walk into IF_STMT_EXTRA_ARGS. */
4062 {
4063 /* Local class, need to look through the whole definition.
4064 TYPE_BINFO might be unset for a partial instantiation. */
4069 }
4070 else
4071 /* Enum, look at the values. */
4085 }
4087 #undef WALK_SUBTREE
4090 }
4092 /* Determines if the expression or type T uses any parameter packs. */
4093 tree
4095 {
4104 }
4106 /* Turn ARG, which may be an expression, type, or a TREE_LIST
4107 representation a base-class initializer into a parameter pack
4108 expansion. If all goes well, the resulting node will be an
4109 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
4110 respectively. */
4111 tree
4113 {
4114 tree result;
4123 {
4124 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
4125 class initializer. In this case, the TREE_PURPOSE will be a
4126 _TYPE node (representing the base class expansion we're
4127 initializing) and the TREE_VALUE will be a TREE_LIST
4128 containing the initialization arguments.
4130 The resulting expansion looks somewhat different from most
4131 expansions. Rather than returning just one _EXPANSION, we
4132 return a TREE_LIST whose TREE_PURPOSE is a
4133 TYPE_PACK_EXPANSION containing the bases that will be
4134 initialized. The TREE_VALUE will be identical to the
4135 original TREE_VALUE, which is a list of arguments that will
4136 be passed to each base. We do not introduce any new pack
4137 expansion nodes into the TREE_VALUE (although it is possible
4138 that some already exist), because the TREE_PURPOSE and
4139 TREE_VALUE all need to be expanded together with the same
4140 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
4141 resulting TREE_PURPOSE will mention the parameter packs in
4142 both the bases and the arguments to the bases. */
4143 tree purpose;
4144 tree value;
4147 /* Determine which parameter packs will be used by the base
4148 class expansion. */
4157 {
4160 arg);
4163 }
4166 {
4167 /* Collect the sets of parameter packs used in each of the
4168 initialization arguments. */
4170 {
4171 /* Determine which parameter packs will be expanded in this
4172 argument. */
4175 }
4176 }
4180 /* Create the pack expansion type for the base type. */
4186 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4187 they will rarely be compared to anything. */
4191 }
4196 /* Build the PACK_EXPANSION_* node. */
4197 result = for_types
4202 {
4203 /* Propagate type and const-expression information. */
4206 /* Mark this read now, since the expansion might be length 0. */
4208 }
4209 else
4210 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4211 they will rarely be compared to anything. */
4214 /* Determine which parameter packs will be expanded. */
4221 /* Make sure we found some parameter packs. */
4223 {
4225 {
4228 else
4230 }
4232 }
4237 /* If the pattern of this pack expansion contains a subtree that has
4238 the extra args mechanism for avoiding partial instantiation, then
4239 force this pack expansion to also use extra args. Otherwise
4240 partial instantiation of this pack expansion may not lower the
4241 level of some parameter packs within the pattern, which would
4242 confuse tsubst_pack_expansion later (PR101764). */
4246 }
4248 /* Checks T for any "bare" parameter packs, which have not yet been
4249 expanded, and issues an error if any are found. This operation can
4250 only be done on full expressions or types (e.g., an expression
4251 statement, "if" condition, etc.), because we could have expressions like:
4253 foo(f(g(h(args)))...)
4255 where "args" is a parameter pack. check_for_bare_parameter_packs
4256 should not be called for the subexpressions args, h(args),
4257 g(h(args)), or f(g(h(args))), because we would produce erroneous
4258 error messages.
4260 Returns TRUE and emits an error if there were bare parameter packs,
4261 returns FALSE otherwise. */
4262 bool
4264 {
4286 /* It's OK for a lambda to have an unexpanded parameter pack from the
4287 containing context, but do complain about unexpanded capture packs. */
4293 {
4294 /* We're in a lambda, but it isn't the innermost class.
4295 This should work, but currently doesn't. */
4298 }
4303 {
4309 }
4312 {
4315 {
4326 else
4331 else
4335 }
4338 }
4341 }
4343 /* Expand any parameter packs that occur in the template arguments in
4344 ARGS. */
4345 tree
4347 {
4356 /* First, determine if we need to expand anything, and the number of
4357 slots we'll need. */
4359 {
4364 {
4368 else
4370 }
4371 else
4372 {
4374 num_result_args++;
4375 }
4376 }
4378 /* If no expansion is necessary, we're done. */
4382 /* Expand arguments. */
4385 non_default_args_count =
4388 {
4391 {
4398 }
4399 else
4400 {
4403 }
4404 }
4408 }
4410 /* Checks if DECL shadows a template parameter.
4412 [temp.local]: A template-parameter shall not be redeclared within its
4413 scope (including nested scopes).
4415 Emits an error and returns TRUE if the DECL shadows a parameter,
4416 returns FALSE otherwise. */
4418 bool
4420 {
4421 tree olddecl;
4423 /* If we're not in a template, we can't possibly shadow a template
4424 parameter. */
4428 /* Figure out what we're shadowing. */
4432 /* If there's no previous binding for this name, we're not shadowing
4433 anything, let alone a template parameter. */
4437 /* If we're not shadowing a template parameter, we're done. Note
4438 that OLDDECL might be an OVERLOAD (or perhaps even an
4439 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4440 node. */
4444 /* We check for decl != olddecl to avoid bogus errors for using a
4445 name inside a class. We check TPFI to avoid duplicate errors for
4446 inline member templates. */
4452 /* Don't complain about the injected class name, as we've already
4453 complained about the class itself. */
4460 else
4465 }
4467 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4468 ORIG_LEVEL, DECL, and TYPE. */
4470 static tree
4474 tree decl,
4475 tree type)
4476 {
4487 }
4490 {
4492 {
4502 }
4505 {
4510 }
4511 };
4515 /* Find the canonical type parameter for the given template type
4516 parameter. Returns the canonical type parameter, which may be TYPE
4517 if no such parameter existed. */
4519 tree
4521 {
4529 }
4531 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4532 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4533 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4534 new one is created. */
4536 static tree
4538 tsubst_flags_t complain)
4539 {
4544 ? (comp_template_parms
4549 {
4554 type);
4569 /* Template template parameters need this. */
4572 {
4579 }
4581 /* Attach the TPI to the decl. */
4584 else
4586 }
4589 }
4591 /* Process information from new template parameter PARM and append it
4592 to the LIST being built. This new parameter is a non-type
4593 parameter iff IS_NON_TYPE is true. This new parameter is a
4594 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4595 is in PARM_LOC. */
4597 tree
4600 {
4606 {
4616 }
4623 {
4629 {
4630 /* [temp.param]
4632 The top-level cv-qualifiers on the template-parameter are
4633 ignored when determining its type. */
4638 && !is_parameter_pack
4639 /* If we're in a nested template parameter list, the template
4640 template parameter could be a parameter pack. */
4642 {
4643 /* This template parameter is not a parameter pack, but it
4644 should be. Complain about "bare" parameter packs. */
4647 /* Recover by calling this a parameter pack. */
4649 }
4650 }
4652 /* A template parameter is not modifiable. */
4661 current_template_depth,
4666 }
4667 else
4668 {
4669 tree t;
4673 {
4675 /* This is for distinguishing between real templates and template
4676 template parameters */
4679 /* any_template_parm_r expects to be able to get the targs of a
4680 DECL_TEMPLATE_RESULT. */
4689 }
4690 else
4691 {
4693 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4696 }
4703 current_template_depth,
4707 }
4711 /* Build requirements for the type/template parameter.
4712 This must be done after SET_DECL_TEMPLATE_PARM_P or
4713 process_template_parm could fail. */
4720 /* Build the parameter node linking the parameter declaration,
4721 its default argument (if any), and its constraints (if any). */
4727 else
4731 }
4733 /* The end of a template parameter list has been reached. Process the
4734 tree list into a parameter vector, converting each parameter into a more
4735 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4736 as PARM_DECLs. */
4738 tree
4740 {
4743 /* Pop the dummy parameter level and add the real one. We do not
4744 morph the dummy parameter in place, as it might have been
4745 captured by a (nested) template-template-parm. */
4748 current_template_parms
4753 {
4759 }
4764 }
4766 // Explicitly indicate the end of the template parameter list. We assume
4767 // that the current template parameters have been constructed and/or
4768 // managed explicitly, as when creating new template template parameters
4769 // from a shorthand constraint.
4770 void
4772 {
4774 }
4776 /* end_template_decl is called after a template declaration is seen. */
4778 void
4780 {
4786 /* This matches the pushlevel in begin_template_parm_list. */
4791 }
4793 /* Takes a TEMPLATE_PARM_P or DECL_TEMPLATE_PARM_P node or a TREE_LIST
4794 thereof, and converts it into an argument suitable to be passed to
4795 the type substitution functions. Note that if the TREE_LIST contains
4796 an error_mark node, the returned argument is error_mark_node. */
4798 tree
4800 {
4811 {
4815 else
4817 }
4823 {
4825 {
4826 /* Turn this argument into a TYPE_ARGUMENT_PACK
4827 with a single element, which expands T. */
4836 }
4837 }
4838 else
4839 {
4841 {
4842 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4843 with a single element, which expands T. */
4853 }
4854 else
4856 }
4858 }
4860 /* If T looks like a generic template argument produced by template_parm_to_arg,
4861 return the corresponding template parameter, otherwise return NULL_TREE. */
4863 static tree
4865 {
4870 {
4875 }
4882 else
4884 }
4886 /* Given a single level of template parameters (a TREE_VEC), return it
4887 as a set of template arguments. */
4889 tree
4891 {
4901 }
4903 /* Given a set of template parameters, return them as a set of template
4904 arguments. The template parameters are represented as a TREE_VEC, in
4905 the form documented in cp-tree.h for template arguments. */
4907 tree
4909 {
4910 tree header;
4915 /* If there is only one level of template parameters, we do not
4916 create a TREE_VEC of TREE_VECs. Instead, we return a single
4917 TREE_VEC containing the arguments. */
4922 {
4927 else
4929 }
4932 }
4934 /* Within the declaration of a template, return the currently active
4935 template parameters as an argument TREE_VEC. */
4937 static tree
4939 {
4941 }
4943 /* Return the fully generic arguments for of TMPL, i.e. what
4944 current_template_args would be while parsing it. */
4946 tree
4948 {
4953 /* DECL_TEMPLATE_RESULT doesn't have the arguments we want. For a template
4954 template parameter, it has no TEMPLATE_INFO; for a partial
4955 specialization, it has the arguments for the primary template, and we
4961 }
4963 /* Return the template arguments corresponding to the template parameters of
4964 TMPL's enclosing scope. When TMPL is a member of a partial specialization,
4965 this returns the arguments for the partial specialization as opposed to those
4966 for the primary template, which is the main difference between this function
4967 and simply using e.g. the TYPE_TI_ARGS of TMPL's DECL_CONTEXT. */
4969 tree
4971 {
4981 }
4983 /* Update the declared TYPE by doing any lookups which were thought to be
4984 dependent, but are not now that we know the SCOPE of the declarator. */
4986 tree
4988 {
4999 /* Don't bother building up the args in this case. */
5001 {
5002 /* tsubst in the args corresponding to the template parameters,
5003 including auto if present. Most things will be unchanged, but
5004 make_typename_type and tsubst_qualified_id will resolve
5005 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
5008 tree pushed;
5010 {
5014 }
5019 }
5025 {
5028 else
5030 }
5032 }
5034 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
5035 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
5036 the new template is a member template. */
5038 static tree
5040 {
5052 /* Propagate module information from the decl. */
5056 }
5058 struct template_parm_data
5059 {
5060 /* The level of the template parameters we are currently
5061 processing. */
5064 /* The index of the specialization argument we are currently
5065 processing. */
5068 /* An array whose size is the number of template parameters. The
5069 elements are nonzero if the parameter has been used in any one
5070 of the arguments processed so far. */
5073 /* An array whose size is the number of template arguments. The
5074 elements are nonzero if the argument makes use of template
5075 parameters of this level. */
5077 };
5079 /* Subroutine of push_template_decl used to see if each template
5080 parameter in a partial specialization is used in the explicit
5081 argument list. If T is of the LEVEL given in DATA (which is
5082 treated as a template_parm_data*), then DATA->PARMS is marked
5083 appropriately. */
5085 static int
5087 {
5095 {
5098 }
5100 /* In C++17 the type of a non-type argument is a deduced context. */
5105 data,
5106 NULL,
5109 /* Return zero so that for_each_template_parm will continue the
5110 traversal of the tree; we want to mark *every* template parm. */
5112 }
5114 /* Process the partial specialization DECL. */
5116 static tree
5118 {
5125 tree inner_parms;
5126 tree inst;
5136 /* A concept cannot be specialized. */
5138 {
5141 }
5146 /* We check that each of the template parameters given in the
5147 partial specialization is used in the argument list to the
5148 specialization. For example:
5150 template <class T> struct S;
5151 template <class T> struct S<T*>;
5153 The second declaration is OK because `T*' uses the template
5154 parameter T, whereas
5156 template <class T> struct S<int>;
5158 is no good. Even trickier is:
5160 template <class T>
5161 struct S1
5162 {
5163 template <class U>
5164 struct S2;
5165 template <class U>
5166 struct S2<T>;
5167 };
5169 The S2<T> declaration is actually invalid; it is a
5170 full-specialization. Of course,
5172 template <class U>
5173 struct S2<T (*)(U)>;
5175 or some such would have been OK. */
5183 {
5188 NULL,
5190 }
5193 {
5194 /* One of the template parms was not used in a deduced context in the
5195 specialization. */
5197 {
5201 }
5205 }
5210 /* [temp.class.spec]
5212 The argument list of the specialization shall not be identical to
5213 the implicit argument list of the primary template. */
5214 tree main_args
5217 && (!flag_concepts
5219 {
5222 "any template arguments; to define the primary template, "
5224 else
5226 "template arguments and is not more constrained than "
5227 "the primary template; to define the primary template, "
5230 }
5232 /* A partial specialization that replaces multiple parameters of the
5233 primary template with a pack expansion is less specialized for those
5234 parameters. */
5236 {
5238 "primary template because it replaces multiple parameters "
5241 /* Avoid crash in process_partial_specialization. */
5243 }
5246 {
5249 /* Avoid crash below. */
5251 }
5253 /* If we aren't in a dependent class, we can actually try deduction. */
5255 /* FIXME we should be able to handle a partial specialization of a
5256 partial instantiation, but currently we can't (c++/41727). */
5259 {
5260 auto_diagnostic_group d;
5263 decl))
5265 maintmpl);
5266 }
5268 /* [temp.spec.partial]
5270 The type of a template parameter corresponding to a specialized
5271 non-type argument shall not be dependent on a parameter of the
5272 specialization.
5274 Also, we verify that pack expansions only occur at the
5275 end of the argument list. */
5278 {
5285 {
5286 /* Extract the arguments from the argument pack. We'll be
5287 iterating over these in the following loop. */
5290 }
5293 {
5295 /* Get the Jth argument in the parameter pack. */
5299 {
5300 /* Pack expansions must come at the end of the
5301 argument list. */
5304 {
5308 else
5311 }
5312 }
5315 /* We only care about the pattern. */
5321 /* This next two lines are the `argument expression is not just a
5322 simple identifier' condition and also the `specialized
5323 non-type argument' bit. */
5328 {
5329 /* Look at the corresponding template parameter,
5330 marking which template parameters its type depends
5331 upon. */
5335 {
5336 /* We haven't yet initialized TPD2. Do so now. */
5338 /* The number of parameters here is the number in the
5339 main template, which, as checked in the assertion
5340 above, is NARGS. */
5344 }
5346 /* Mark the template parameters. But this time, we're
5347 looking for the template parameters of the main
5348 template, not in the specialization. */
5355 NULL,
5359 {
5360 /* The type depended on some template parameters.
5361 If they are fully specialized in the
5362 specialization, that's OK. */
5371 "type %qT of template argument %qE depends "
5373 "type %qT of template argument %qE depends "
5375 type,
5376 arg);
5377 }
5378 }
5379 }
5380 }
5382 /* We should only get here once. */
5386 // Build the template decl.
5393 /* Give template template parms a DECL_CONTEXT of the template
5394 for which they are a parameter. */
5396 {
5400 }
5403 /* We didn't register this in check_explicit_specialization so we could
5404 wait until the constraints were set. */
5406 else
5416 {
5422 {
5430 "declaration of %qD ambiguates earlier template "
5434 "partial specialization of %qD after instantiation "
5436 }
5437 }
5440 }
5442 /* PARM is a template parameter of some form; return the corresponding
5443 TEMPLATE_PARM_INDEX. */
5445 static tree
5447 {
5460 }
5462 /* Subroutine of fixed_parameter_pack_p below. Look for any template
5463 parameter packs used by the template parameter PARM. */
5465 static void
5467 {
5468 /* A type parm can't refer to another parm. */
5472 {
5476 }
5482 {
5486 else
5488 }
5489 }
5491 /* PARM is a template parameter pack. Return any parameter packs used in
5492 its type or the type of any of its template parameters. If there are
5493 any such packs, it will be instantiated into a fixed template parameter
5494 list by partial instantiation rather than be fully deduced. */
5496 tree
5498 {
5499 /* This can only be true in a member template. */
5502 /* This can only be true for a parameter pack. */
5505 /* A type parm can't refer to another parm. */
5519 }
5521 /* Check that a template declaration's use of default arguments and
5522 parameter packs is not invalid. Here, PARMS are the template
5523 parameters. IS_PRIMARY is true if DECL is the thing declared by
5524 a primary template. IS_PARTIAL is true if DECL is a partial
5525 specialization.
5527 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
5528 function template declaration or a friend class template
5529 declaration. In the function case, 1 indicates a declaration, 2
5530 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
5531 emitted for extraneous default arguments.
5533 Returns TRUE if there were no errors found, FALSE otherwise. */
5535 bool
5538 {
5541 tree parm_level;
5544 /* [temp.param]
5546 A default template-argument shall not be specified in a
5547 function template declaration or a function template definition, nor
5548 in the template-parameter-list of the definition of a member of a
5549 class template. */
5553 /* You can't have a function template declaration in a local
5554 scope, nor you can you define a member of a class template in a
5555 local scope. */
5563 /* A lambda doesn't have an explicit declaration; don't complain
5564 about the parms of the enclosing class. */
5571 /* If this is either a friend defined in the scope of the class
5572 or a member function. */
5578 /* And, if it was a member function, it really was defined in
5579 the scope of the class. */
5582 /* We already checked these parameters when the template was
5583 declared, so there's no need to do it again now. This function
5584 was defined in class scope, but we're processing its body now
5585 that the class is complete. */
5588 /* Core issue 226 (C++0x only): the following only applies to class
5589 templates. */
5592 {
5593 /* [temp.param]
5595 If a template-parameter has a default template-argument, all
5596 subsequent template-parameters shall have a default
5597 template-argument supplied. */
5599 {
5606 {
5616 {
5618 /* For better subsequent error-recovery, we indicate that
5619 there should have been a default argument. */
5622 }
5624 && !is_friend_decl
5625 /* Don't complain about an enclosing partial
5626 specialization. */
5631 /* A fixed parameter pack will be partially
5632 instantiated into a fixed length list. */
5634 {
5635 /* A primary class template, primary variable template
5636 (DR 2032), or alias template can only have one
5637 parameter pack, at the end of the template
5638 parameter list. */
5646 }
5647 }
5648 }
5649 }
5652 || is_partial
5653 || !is_primary
5655 /* For an ordinary class template, default template arguments are
5656 allowed at the innermost level, e.g.:
5657 template <class T = int>
5658 struct S {};
5659 but, in a partial specialization, they're not allowed even
5660 there, as we have in [temp.class.spec]:
5662 The template parameter list of a specialization shall not
5663 contain default template argument values.
5665 So, for a partial specialization, or for a function template
5666 (in C++98/C++03), we look at all of them. */
5667 ;
5668 else
5669 /* But, for a primary class template that is not a partial
5670 specialization we look at all template parameters except the
5671 innermost ones. */
5674 /* Figure out what error message to issue. */
5689 else
5690 /* Per [temp.param]/9, "A default template-argument shall not be
5691 specified in the template-parameter-lists of the definition of
5692 a member of a class template that appears outside of the member's
5693 class.", thus if we aren't handling a member of a class template
5694 there is no need to examine the parameters. */
5698 /* If we're inside a class definition, there's no need to
5699 examine the parameters to the class itself. On the one
5700 hand, they will be checked when the class is defined, and,
5701 on the other, default arguments are valid in things like:
5702 template <class T = double>
5703 struct S { template <class U> void f(U); };
5704 Here the default argument for `S' has no bearing on the
5705 declaration of `f'. */
5707 else
5708 /* Check everything. */
5714 {
5721 {
5726 {
5728 {
5735 }
5737 /* Clear out the default argument so that we are not
5738 confused later. */
5740 }
5741 }
5743 /* At this point, if we're still interested in issuing messages,
5744 they must apply to classes surrounding the object declared. */
5748 }
5751 }
5753 /* Worker for push_template_decl_real, called via
5754 for_each_template_parm. DATA is really an int, indicating the
5755 level of the parameters we are interested in. If T is a template
5756 parameter of that level, return nonzero. */
5758 static int
5760 {
5766 else
5769 }
5771 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5772 DATA is really an int, indicating the innermost outer level of parameters.
5773 If T is a template parameter of that level or further out, return
5774 nonzero. */
5776 static int
5778 {
5784 else
5787 }
5789 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5790 parameters given by current_template_args, or reuses a
5791 previously existing one, if appropriate. Returns the DECL, or an
5792 equivalent one, if it is replaced via a call to duplicate_decls.
5794 If IS_FRIEND is true, DECL is a friend declaration. */
5796 tree
5798 {
5802 /* See if this is a partial specialization. */
5811 /* No surprising friend functions. */
5816 tree ctx;
5818 /* For a friend, we want the context of the friend, not
5819 the type of which it is a friend. */
5823 /* In the case of a virtual function, we want the class in which
5824 it is defined. */
5826 else
5827 /* Otherwise, if we're currently defining some class, the DECL
5828 is assumed to be a member of the class. */
5837 /* See if this is a primary template. */
5841 /* A friend template that specifies a class context, i.e.
5842 template <typename T> friend void A<T>::f();
5843 is not primary. */
5844 ;
5846 /* Lambdas are not primary. */
5847 ;
5848 else
5851 /* True if the template is a member template, in the sense of
5852 [temp.mem]. */
5856 {
5864 {
5867 }
5869 {
5871 {
5874 }
5876 {
5877 /* [temp.mem]
5879 A destructor shall not be a member template. */
5883 }
5890 {
5891 /* [basic.stc.dynamic.allocation]
5893 An allocation function can be a function
5894 template. ... Template allocation functions shall
5895 have two or more parameters. */
5898 }
5899 }
5905 /* alias-declaration */
5911 else
5912 {
5915 }
5916 }
5923 /* Check to see that the rules regarding the use of default
5924 arguments are not being violated. We check args for a friend
5925 functions when we know whether it's a definition, introducing
5926 declaration or re-declaration. */
5931 /* Ensure that there are no parameter packs in the type of this
5932 declaration that have not been expanded. */
5934 {
5935 /* Check each of the arguments individually to see if there are
5936 any bare parameter packs. */
5942 {
5945 {
5946 /* This is a PARM_DECL that contains unexpanded parameter
5947 packs. We have already complained about this in the
5948 check_for_bare_parameter_packs call, so just replace
5949 these types with ERROR_MARK_NODE. */
5952 }
5956 }
5958 /* Check for bare parameter packs in the return type and the
5959 exception specifiers. */
5961 /* Errors were already issued, set return type to int
5962 as the frontend doesn't expect error_mark_node as
5963 the return type. */
5967 }
5968 else
5969 {
5973 {
5976 }
5981 }
5990 {
5991 /* Does not get a template head. */
5994 }
6001 {
6006 /* If DECL is a TYPE_DECL for a class-template, then there won't
6007 be DECL_LANG_SPECIFIC. The information equivalent to
6008 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
6012 {
6013 /* Since a template declaration already existed for this
6014 class-type, we must be redeclaring it here. Make sure
6015 that the redeclaration is valid. */
6017 current_template_parms,
6019 /* We don't need to create a new TEMPLATE_DECL; just use the
6020 one we already had. */
6022 }
6023 else
6024 {
6026 member_template_p);
6031 {
6032 /* A specialization of a member template of a template
6033 class. */
6037 }
6038 }
6039 }
6040 else
6041 {
6047 {
6050 }
6058 {
6059 /* The declaration is a specialization of a member
6060 template, declared outside the class. Therefore, the
6061 innermost template arguments will be NULL, so we
6062 replace them with the arguments determined by the
6063 earlier call to check_explicit_specialization. */
6066 tree new_tmpl
6068 member_template_p);
6076 args,
6079 }
6081 /* Make sure the template headers we got make sense. */
6086 {
6091 }
6092 else
6094 {
6099 {
6103 else
6107 /* Avoid crash in import_export_decl. */
6110 }
6115 /* Can happen in erroneous input. */
6117 else
6119 }
6121 /* Check that the parms are used in the appropriate qualifying scopes
6122 in the declarator. */
6126 {
6132 /* Avoid crash in import_export_decl. */
6135 }
6137 /* Check that the constraints for each enclosing template scope are
6138 consistent with the original declarations. */
6140 {
6144 {
6147 }
6149 {
6151 {
6155 }
6158 }
6159 }
6160 }
6165 {
6166 /* Push template declarations for global functions and types.
6167 Note that we do not try to push a global template friend
6168 declared in a template class; such a thing may well depend on
6169 the template parameters of the class and we'll push it when
6170 instantiating the befriending class. */
6173 {
6178 /* pushdecl may have found an existing template. */
6180 {
6183 }
6184 }
6186 {
6187 /* Record this decl as belonging to the current class. It's
6188 not chained onto anything else. */
6192 }
6193 }
6195 /* The type may have been completed, or (erroneously) changed. */
6199 {
6201 {
6206 /* Give template template parms a DECL_CONTEXT of the template
6207 for which they are a parameter. */
6210 {
6214 }
6218 {
6221 {
6222 /* ??? Why don't we do this here for all templates? */
6225 }
6228 }
6229 }
6231 /* The DECL_TI_ARGS of DECL contains full set of arguments
6232 referring wback to its most general template. If TMPL is a
6233 specialization, ARGS may only have the innermost set of
6234 arguments. Add the missing argument levels if necessary. */
6242 else
6243 {
6246 }
6247 }
6250 && !is_friend
6253 /* Set DECL_COMDAT on template instantiations; if we force
6254 them to be emitted by explicit instantiation,
6255 mark_needed will tell cgraph to do the right thing. */
6261 }
6263 /* FN is an inheriting constructor that inherits from the constructor
6264 template INHERITED; turn FN into a constructor template with a matching
6265 template header. */
6267 tree
6269 {
6270 tree inner_parms
6273 tree parms
6282 }
6284 /* Called when a class template TYPE is redeclared with the indicated
6285 template PARMS, e.g.:
6287 template <class T> struct S;
6288 template <class T> struct S {}; */
6290 bool
6292 {
6293 tree tmpl;
6294 tree tmpl_parms;
6298 {
6301 }
6305 /* The type is nested in some template class. Nothing to worry
6306 about here; there are no new template parameters for the nested
6307 type. */
6311 {
6313 tmpl);
6315 }
6321 {
6331 }
6334 {
6335 tree tmpl_parm;
6336 tree parm;
6348 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
6349 TEMPLATE_DECL. */
6359 {
6360 auto_diagnostic_group d;
6364 else
6367 }
6369 /* The parameters can be declared to introduce different
6370 constraints. */
6374 {
6375 auto_diagnostic_group d;
6381 }
6383 /* Give each template template parm in this redeclaration a
6384 DECL_CONTEXT of the template for which they are a parameter. */
6386 {
6389 }
6390 }
6399 /* Two classes with different constraints declare different entities. */
6401 {
6402 auto_diagnostic_group d;
6408 }
6411 }
6413 /* The actual substitution part of instantiate_non_dependent_expr,
6414 to be used when the caller has already checked
6415 !instantiation_dependent_uneval_expression_p (expr)
6416 and cleared processing_template_decl. */
6418 tree
6420 {
6423 complain,
6425 }
6427 /* Instantiate the non-dependent expression EXPR. */
6429 tree
6432 {
6437 {
6438 /* The caller should have checked this already. */
6440 processing_template_decl_sentinel s;
6442 }
6444 }
6446 /* Like instantiate_non_dependent_expr, but return NULL_TREE if the
6447 expression is dependent or non-constant. */
6449 tree
6451 {
6455 {
6458 else
6459 {
6460 processing_template_decl_sentinel s;
6462 }
6463 }
6465 }
6467 /* True iff T is a specialization of a variable template. */
6469 bool
6471 {
6476 }
6478 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
6479 template declaration, or a TYPE_DECL for an alias declaration. */
6481 bool
6483 {
6491 }
6493 /* If T is a specialization of an alias template, return it; otherwise return
6494 NULL_TREE. If TRANSPARENT_TYPEDEFS is true, look through other aliases. */
6496 tree
6499 {
6503 /* It's an alias template specialization if it's an alias and its
6504 TYPE_NAME is a specialization of a primary template. */
6506 {
6513 transparent_typedefs);
6514 }
6517 }
6519 /* Data structure for complex_alias_template_*. */
6521 struct uses_all_template_parms_data
6522 {
6525 };
6527 /* walk_tree callback for complex_alias_template_p. */
6529 static tree
6531 {
6536 {
6541 {
6545 }
6548 }
6553 /* An alias template with a pack expansion that expands a pack from the
6554 enclosing class needs to be considered complex, to avoid confusion with
6555 the same pack being used as an argument to the alias's own template
6556 parameter (91966). */
6559 {
6568 /* Consider the expanded packs to be used outside the expansion... */
6570 }
6572 /* ...but don't walk into the pattern. Consider PR104008:
6574 template <typename T, typename... Ts>
6575 using IsOneOf = disjunction<is_same<T, Ts>...>;
6577 where IsOneOf seemingly uses all of its template parameters in its
6578 expansion (and does not expand a pack from the enclosing class), so the
6579 alias was not marked as complex. However, if it is used like
6580 "IsOneOf<T>", the empty pack for Ts means that T no longer appears in the
6581 expansion. So only Ts is considered used by the pack expansion. */
6585 }
6587 /* An alias template is complex from a SFINAE perspective if a template-id
6588 using that alias can be ill-formed when the expansion is not, as with
6589 the void_t template.
6591 Returns 1 if always complex, 0 if not complex, -1 if complex iff any of the
6592 template arguments are empty packs. */
6594 static bool
6596 {
6597 /* A renaming alias isn't complex. */
6601 /* Any other constrained alias is complex. */
6620 }
6622 /* If T is a specialization of a complex alias template with dependent
6623 template-arguments, return it; otherwise return NULL_TREE. If T is a
6624 typedef to such a specialization, return the specialization. */
6626 tree
6628 {
6639 && (any_dependent_template_arguments_p
6644 {
6647 }
6650 }
6652 /* Return the number of innermost template parameters in TMPL. */
6654 static int
6656 {
6659 }
6661 /* Return either TMPL or another template that it is equivalent to under DR
6662 1286: An alias that just changes the name of a template is equivalent to
6663 the other template. */
6665 static tree
6667 {
6670 {
6671 /* Determine if the alias is equivalent to an underlying template. */
6673 /* The underlying type may have been ill-formed. Don't proceed. */
6686 /* Does the alias add cv-quals? */
6694 /* Are any default template arguments equivalent? */
6699 {
6704 }
6706 /* If TMPL adds or changes any constraints, it isn't equivalent. I think
6707 it's appropriate to treat a less-constrained alias as equivalent. */
6711 /* Alias is equivalent. Strip it and repeat. */
6713 }
6714 top_break:;
6717 }
6719 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6720 must be a reference-to-function or a pointer-to-function type, as specified
6721 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6722 and check that the resulting function has external linkage. */
6724 static tree
6726 tsubst_flags_t complain)
6727 {
6730 linkage_kind linkage;
6748 /* [temp.arg.nontype]/1
6750 A template-argument for a non-type, non-template template-parameter
6751 shall be one of:
6752 [...]
6753 -- the address of an object or function with external [C++11: or
6754 internal] linkage. */
6758 {
6760 {
6767 else
6770 }
6772 }
6777 {
6779 {
6785 else
6789 }
6791 }
6793 accept:
6795 {
6798 else
6800 }
6805 }
6807 /* Subroutine of convert_nontype_argument.
6808 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6809 Emit an error otherwise. */
6811 static bool
6813 tsubst_flags_t complain)
6814 {
6830 {
6836 else
6838 }
6840 }
6842 /* Returns TRUE iff the address of OP is value-dependent.
6844 14.6.2.4 [temp.dep.temp]:
6845 A non-integral non-type template-argument is dependent if its type is
6846 dependent or it has either of the following forms
6847 qualified-id
6848 & qualified-id
6849 and contains a nested-name-specifier which specifies a class-name that
6850 names a dependent type.
6852 We generalize this to just say that the address of a member of a
6853 dependent class is value-dependent; the above doesn't cover the
6854 address of a static data member named with an unqualified-id. */
6856 static bool
6858 {
6861 /* We could use get_inner_reference here, but there's no need;
6862 this is only relevant for template non-type arguments, which
6863 can only be expressed as &id-expression. */
6865 {
6876 }
6879 }
6881 /* The next set of functions are used for providing helpful explanatory
6882 diagnostics for failed overload resolution. Their messages should be
6883 indented by two spaces for consistency with the messages in
6884 call.cc */
6886 static int
6888 {
6890 }
6892 /* Other failure functions should call this one, to provide a single function
6893 for setting a breakpoint on. */
6895 static int
6897 {
6899 }
6901 static int
6903 {
6908 }
6910 static int
6912 {
6918 }
6920 static int
6922 {
6926 }
6928 static int
6930 {
6933 " template parameter %qD is not a parameter pack, but "
6937 }
6939 static int
6941 {
6944 " template argument %qE does not match "
6948 }
6950 static int
6952 {
6956 }
6958 static int
6960 {
6966 }
6968 static int
6970 {
6972 {
6977 else
6979 " deduced conflicting values for non-type parameter "
6981 }
6983 }
6985 static int
6987 {
6990 " variable-sized array type %qT is not "
6992 arg);
6994 }
6996 static int
6998 {
7002 arg);
7004 }
7006 static int
7008 {
7010 {
7016 else
7021 }
7023 }
7025 static int
7027 {
7029 }
7031 static int
7034 {
7036 }
7038 static int
7041 {
7047 }
7049 static int
7052 {
7055 {
7063 }
7065 }
7067 static int
7069 {
7072 " template parameters of a template template argument are "
7075 }
7077 static int
7079 {
7085 }
7087 static int
7089 {
7094 }
7096 /* Subroutine of convert_nontype_argument, to check whether EXPR, as an
7097 argument for TYPE, points to an unsuitable object.
7099 Also adjust the type of the index in C++20 array subobject references. */
7101 static bool
7103 {
7105 {
7106 CASE_CONVERT:
7108 complain);
7112 complain);
7115 {
7119 }
7123 {
7129 {
7133 /* Canonicalize array offsets to ptrdiff_t; how they were
7134 written doesn't matter for subobject identity. */
7137 }
7140 {
7143 "%qE is not a valid template argument of type %qT "
7147 }
7149 {
7152 "%qE is not a valid template argument of type %qT "
7156 }
7159 {
7162 "%qE is not a valid template argument of type %qT "
7165 }
7166 /* C++17: For a non-type template-parameter of reference or pointer
7167 type, the value of the constant expression shall not refer to (or
7168 for a pointer type, shall not be the address of):
7169 * a subobject (4.5),
7170 * a temporary object (15.2),
7171 * a string literal (5.13.5),
7172 * the result of a typeid expression (8.2.8), or
7173 * a predefined __func__ variable (11.4.1). */
7175 {
7178 decl);
7180 }
7182 && !(same_type_ignoring_top_level_qualifiers_p
7185 {
7190 }
7192 {
7196 decl);
7198 }
7199 }
7207 else
7208 {
7210 {
7213 "because %qD is a variable, not the address of "
7216 }
7217 else
7218 {
7224 }
7225 }
7226 }
7229 }
7231 /* Return a VAR_DECL for the C++20 template parameter object corresponding to
7232 template argument EXPR. */
7234 static tree
7236 {
7241 {
7246 }
7250 /* This is no longer a compound literal. */
7254 }
7256 /* The template arguments corresponding to template parameter objects of types
7257 that contain pointers to members. */
7261 /* Find or build an nttp object for (already-validated) EXPR with name
7262 NAME. */
7264 tree
7266 {
7283 {
7284 /* If EXPR contains any PTRMEM_CST, they will get clobbered by
7285 lower_var_init before we're done mangling. So store the original
7286 value elsewhere. */
7289 }
7294 }
7296 /* Return the actual template argument corresponding to template parameter
7297 object VAR. */
7299 tree
7301 {
7305 }
7307 /* Attempt to convert the non-type template parameter EXPR to the
7308 indicated TYPE. If the conversion is successful, return the
7309 converted value. If the conversion is unsuccessful, return
7310 NULL_TREE if we issued an error message, or error_mark_node if we
7311 did not. We issue error messages for out-and-out bad template
7312 parameters, but not simply because the conversion failed, since we
7313 might be just trying to do argument deduction. Both TYPE and EXPR
7314 must be non-dependent.
7316 The conversion follows the special rules described in
7317 [temp.arg.nontype], and it is much more strict than an implicit
7318 conversion.
7320 This function is called twice for each template argument (see
7321 lookup_template_class for a more accurate description of this
7322 problem). This means that we need to handle expressions which
7323 are not valid in a C++ source, but can be created from the
7324 first call (for instance, casts to perform conversions). These
7325 hacks can go away after we fix the double coercion problem. */
7327 static tree
7329 {
7330 tree expr_type;
7333 /* Detect immediately string literals as invalid non-type argument.
7334 This special-case is not needed for correctness (we would easily
7335 catch this later), but only to provide better diagnostic for this
7336 common user mistake. As suggested by DR 100, we do not mention
7337 linkage issues in the diagnostic as this is not the point. */
7339 {
7345 }
7347 /* Add the ADDR_EXPR now for the benefit of
7348 value_dependent_expression_p. */
7351 {
7355 }
7357 /* If we are in a template, EXPR may be non-dependent, but still
7358 have a syntactic, rather than semantic, form. For example, EXPR
7359 might be a SCOPE_REF, rather than the VAR_DECL to which the
7360 SCOPE_REF refers. Preserving the qualifying scope is necessary
7361 so that access checking can be performed when the template is
7362 instantiated -- but here we need the resolved form so that we can
7363 convert the argument. */
7375 /* If the argument is non-dependent, perform any conversions in
7376 non-dependent context as well. */
7384 else
7387 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
7388 to a non-type argument of "nullptr". */
7392 /* In C++11, integral or enumeration non-type template arguments can be
7393 arbitrary constant expressions. Pointer and pointer to
7394 member arguments can be general constant expressions that evaluate
7395 to a null value, but otherwise still need to be of a specific form. */
7397 {
7399 /* A PTRMEM_CST is already constant, and a valid template
7400 argument for a parameter of pointer to member type, we just want
7401 to leave it in that form rather than lower it to a
7405 {
7406 /* C++17: A template-argument for a non-type template-parameter shall
7407 be a converted constant expression (8.20) of the type of the
7408 template-parameter. */
7411 /* Make sure we return NULL_TREE only if we have really issued
7412 an error, as described above. */
7415 {
7418 }
7421 /* EXPR may have become value-dependent. */
7423 }
7425 {
7430 }
7431 }
7435 else
7438 /* HACK: Due to double coercion, we can get a
7439 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
7440 which is the tree that we built on the first call (see
7441 below when coercing to reference to object or to reference to
7442 function). We just strip everything and get to the arg.
7443 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
7444 for examples. */
7446 {
7447 /* Check this before we strip *& to avoid redundancy. */
7456 {
7457 /* ??? Maybe we could use convert_from_reference here, but we
7458 would need to relax its constraints because the NOP_EXPR
7459 could actually change the type to something more cv-qualified,
7460 and this is not folded by convert_from_reference. */
7465 && (same_type_ignoring_top_level_qualifiers_p
7468 {
7471 }
7472 }
7473 }
7475 /* [temp.arg.nontype]/5, bullet 1
7477 For a non-type template-parameter of integral or enumeration type,
7478 integral promotions (_conv.prom_) and integral conversions
7479 (_conv.integral_) are applied. */
7482 {
7484 {
7489 }
7494 /* Notice that there are constant expressions like '4 % 0' which
7495 do not fold into integer constants. */
7497 {
7499 {
7503 else
7509 /* else cxx_constant_value complained but gave us
7510 a real constant, so go ahead. */
7512 {
7513 /* Some assemble time constant expressions like
7514 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
7515 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
7516 as we can emit them into .rodata initializers of
7517 variables, yet they can't fold into an INTEGER_CST at
7518 compile time. Refuse them here. */
7523 }
7524 }
7525 else
7527 }
7529 /* Avoid typedef problems. */
7532 }
7533 /* [temp.arg.nontype]/5, bullet 2
7535 For a non-type template-parameter of type pointer to object,
7536 qualification conversions (_conv.qual_) and the array-to-pointer
7537 conversion (_conv.array_) are applied. */
7539 {
7542 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
7543 decay_conversion or an explicit cast. If it's a problematic cast,
7544 we'll complain about it below. */
7546 {
7551 {
7554 }
7555 }
7557 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
7559 A template-argument for a non-type, non-template template-parameter
7560 shall be one of: [...]
7562 -- the name of a non-type template-parameter;
7563 -- the address of an object or function with external linkage, [...]
7564 expressed as "& id-expression" where the & is optional if the name
7565 refers to a function or array, or if the corresponding
7566 template-parameter is a reference.
7568 Here, we do not care about functions, as they are invalid anyway
7569 for a parameter of type pointer-to-object. */
7572 /* Non-type template parameters are OK. */
7573 ;
7578 /* Other values, like integer constants, might be valid
7579 non-type arguments of some other type. */
7589 }
7590 /* [temp.arg.nontype]/5, bullet 3
7592 For a non-type template-parameter of type reference to object, no
7593 conversions apply. The type referred to by the reference may be more
7594 cv-qualified than the (otherwise identical) type of the
7595 template-argument. The template-parameter is bound directly to the
7596 template-argument, which must be an lvalue. */
7598 {
7600 expr_type))
7604 {
7609 }
7612 {
7617 }
7619 /* [temp.arg.nontype]/1
7621 A template-argument for a non-type, non-template template-parameter
7622 shall be one of: [...]
7624 -- the address of an object or function with external linkage. */
7627 {
7630 {
7633 "because a reference variable does not have a constant "
7636 }
7637 }
7640 /* OK, dependent reference. We don't want to ask whether a DECL is
7642 else
7643 {
7648 }
7652 }
7653 /* [temp.arg.nontype]/5, bullet 4
7655 For a non-type template-parameter of type pointer to function, only
7656 the function-to-pointer conversion (_conv.func_) is applied. If the
7657 template-argument represents a set of overloaded functions (or a
7658 pointer to such), the matching function is selected from the set
7659 (_over.over_). */
7661 {
7662 /* If the argument is a template-id, we might not have enough
7663 context information to decay the pointer. */
7665 {
7669 }
7672 /* Null pointer values are OK in C++11. */
7678 }
7679 /* [temp.arg.nontype]/5, bullet 5
7681 For a non-type template-parameter of type reference to function, no
7682 conversions apply. If the template-argument represents a set of
7683 overloaded functions, the matching function is selected from the set
7684 (_over.over_). */
7686 {
7688 {
7690 {
7695 }
7697 }
7702 }
7703 /* [temp.arg.nontype]/5, bullet 6
7705 For a non-type template-parameter of type pointer to member function,
7706 no conversions apply. If the template-argument represents a set of
7707 overloaded member functions, the matching member function is selected
7708 from the set (_over.over_). */
7710 {
7715 /* [temp.arg.nontype] bullet 1 says the pointer to member
7716 expression must be a pointer-to-member constant. */
7721 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
7722 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
7725 }
7726 /* [temp.arg.nontype]/5, bullet 7
7728 For a non-type template-parameter of type pointer to data member,
7729 qualification conversions (_conv.qual_) are applied. */
7731 {
7732 /* [temp.arg.nontype] bullet 1 says the pointer to member
7733 expression must be a pointer-to-member constant. */
7741 }
7743 {
7745 {
7750 }
7752 }
7754 {
7755 /* Replace the argument with a reference to the corresponding template
7756 parameter object. */
7761 }
7762 /* A template non-type parameter must be one of the above. */
7763 else
7766 /* Sanity check: did we actually convert the argument to the
7767 right type? */
7771 }
7773 /* Subroutine of coerce_template_template_parms, which returns 1 if
7774 PARM_PARM and ARG_PARM match using the rule for the template
7775 parameters of template template parameters. Both PARM and ARG are
7776 template parameters; the rest of the arguments are the same as for
7777 coerce_template_template_parms.
7778 */
7779 static int
7781 tree arg,
7782 tsubst_flags_t complain,
7783 tree in_decl,
7784 tree outer_args)
7785 {
7794 {
7796 /* We encounter instantiations of templates like
7797 template <template <template <class> class> class TT>
7798 class C; */
7799 {
7803 }
7804 /* Fall through. */
7809 /* Argument is a parameter pack but parameter is not. */
7814 /* The tsubst call is used to handle cases such as
7816 template <int> class C {};
7817 template <class T, template <T> class TT> class D {};
7818 D<int, C> d;
7820 i.e. the parameter list of TT depends on earlier parameters. */
7822 {
7827 }
7831 /* Argument is a parameter pack but parameter is not. */
7838 }
7841 }
7843 /* Coerce template argument list ARGLIST for use with template
7844 template-parameter TEMPL. */
7846 static tree
7848 tsubst_flags_t complain)
7849 {
7850 /* Consider an example where a template template parameter declared as
7852 template <class T, class U = std::allocator<T> > class TT
7854 The template parameter level of T and U are one level larger than
7855 of TT. To proper process the default argument of U, say when an
7856 instantiation `TT<int>' is seen, we need to build the full
7857 arguments containing {int} as the innermost level. Outer levels,
7858 available when not appearing as default template argument, can be
7859 obtained from the arguments of the enclosing template.
7861 Suppose that TT is later substituted with std::vector. The above
7862 instantiation is `TT<int, std::allocator<T> >' with TT at
7863 level 1, and T at level 2, while the template arguments at level 1
7864 becomes {std::vector} and the inner level 2 is {int}. */
7870 {
7871 /* This is an argument of the current template, so we haven't set
7872 DECL_CONTEXT yet. We can also get here when level-lowering a
7873 bound ttp. */
7874 tree relevant_template_parms;
7876 /* Parameter levels that are greater than the level of the given
7877 template template parm are irrelevant. */
7884 }
7891 }
7893 /* A cache of template template parameters with match-all default
7894 arguments. */
7897 /* T is a bound template template-parameter. Copy its arguments into default
7898 arguments of the template template-parameter's template parameters. */
7900 static tree
7902 {
7925 {
7928 {
7931 }
7932 }
7936 }
7938 /* ARG is a bound potential template template-argument, and PARGS is a list
7939 of arguments for the corresponding template template-parameter. Adjust
7940 PARGS as appropriate for application to ARG's template, and if ARG is a
7941 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7942 arguments to the template template parameter. */
7944 static tree
7946 {
7950 {
7951 /* When comparing two template template-parameters in partial ordering,
7952 rewrite the one currently being used as an argument to have default
7953 arguments for all parameters. */
7959 }
7960 else
7961 {
7962 tree aparms
7965 }
7968 }
7970 /* Subroutine of unify for the case when PARM is a
7971 BOUND_TEMPLATE_TEMPLATE_PARM. */
7973 static int
7976 {
7980 /* The template template parm might be variadic and the argument
7981 not, so flatten both argument lists. */
7986 {
7987 /* In keeping with P0522R0, adjust P's template arguments
7988 to apply to A's template; then flatten it again. */
7996 /* If the P0522 adjustment eliminated a pack expansion, deduce
7997 empty packs. */
8003 }
8004 else
8005 {
8006 /* Deduce arguments T, i from TT<T> or TT<i>.
8007 We check each element of PARMVEC and ARGVEC individually
8008 rather than the whole TREE_VEC since they can have
8009 different number of elements, which is allowed under N2555. */
8013 /* Check if the parameters end in a pack, making them
8014 variadic. */
8021 /* If the template argument list of P contains a pack
8022 expansion that is not the last template argument, the
8023 entire template argument list is a non-deduced
8024 context. */
8042 DEDUCE_EXACT,
8045 }
8048 }
8050 /* Return 1 if PARM_TMPL and ARG_TMPL match using rule for
8051 template template parameters.
8053 Consider the example:
8054 template <class T> class A;
8055 template<template <class U> class TT> class B;
8057 For B<A>, PARM_TMPL is TT, while ARG_TMPL is A,
8058 and OUTER_ARGS contains A. */
8060 static int
8062 tree arg_tmpl,
8063 tsubst_flags_t complain,
8064 tree in_decl,
8065 tree outer_args)
8066 {
8082 {
8083 /* P0522R0: A template template-parameter P is at least as specialized as
8084 a template template-argument A if, given the following rewrite to two
8085 function templates, the function template corresponding to P is at
8086 least as specialized as the function template corresponding to A
8087 according to the partial ordering rules for function templates
8088 ([temp.func.order]). Given an invented class template X with the
8089 template parameter list of A (including default arguments):
8091 * Each of the two function templates has the same template parameters,
8092 respectively, as P or A.
8094 * Each function template has a single function parameter whose type is
8095 a specialization of X with template arguments corresponding to the
8096 template parameters from the respective function template where, for
8097 each template parameter PP in the template parameter list of the
8098 function template, a corresponding template argument AA is formed. If
8099 PP declares a parameter pack, then AA is the pack expansion
8100 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
8102 If the rewrite produces an invalid type, then P is not at least as
8103 specialized as A. */
8105 /* So coerce P's args to apply to A's parms, and then deduce between A's
8106 args and the converted args. If that succeeds, A is at least as
8107 specialized as P, so they match.*/
8113 /* PARM and ARG might be at different template depths, and we want to
8114 pass the right additional levels of args when coercing PARGS to
8115 ARG_PARMS in case we need to do any substitution into non-type
8116 template parameter types.
8118 OUTER_ARGS are not the right outer levels in this case, as they are
8119 the args we're building up for PARM, and for the coercion we want the
8120 args for ARG. If DECL_CONTEXT isn't set for a template template
8121 parameter, we can assume that it's in the current scope. In that case
8122 we might end up adding more levels than needed, but that shouldn't be
8123 a problem; any args we need to refer to are at the right level. */
8134 {
8140 }
8141 }
8143 /* Determine whether we have a parameter pack at the end of the
8144 template template parameter's template parameter list. */
8146 {
8153 {
8167 }
8168 }
8174 /* Check all of the template parameters except the parameter pack at
8175 the end (if any). */
8177 {
8186 outer_args))
8189 }
8192 {
8193 /* Check each of the template parameters in the template
8194 argument against the template parameter pack at the end of
8195 the template template parameter. */
8202 {
8209 outer_args))
8211 }
8212 }
8215 }
8217 /* Verifies that the deduced template arguments (in TARGS) for the
8218 template template parameters (in TPARMS) represent valid bindings,
8219 by comparing the template parameter list of each template argument
8220 to the template parameter list of its corresponding template
8221 template parameter, in accordance with DR150. This
8222 routine can only be called after all template arguments have been
8223 deduced. It will return TRUE if all of the template template
8224 parameter bindings are okay, FALSE otherwise. */
8225 bool
8227 {
8231 /* We're dealing with template parms in this process. */
8237 {
8242 {
8247 {
8248 /* Look inside the argument pack. */
8251 }
8254 {
8256 /* Extract the next argument from the argument
8257 pack. */
8261 /* Look at the pattern of the pack expansion. */
8264 /* Extract the template parameters from the template
8265 argument. */
8269 /* Verify that we can coerce the template template
8270 parameters from the template argument to the template
8271 parameter. This requires an exact match. */
8273 && !coerce_template_template_parms
8275 targ,
8276 tf_none,
8277 tparm,
8278 targs))
8279 {
8282 }
8283 }
8284 }
8285 }
8287 out:
8291 }
8293 /* Since type attributes aren't mangled, we need to strip them from
8294 template type arguments. */
8296 tree
8298 {
8308 }
8310 /* And from inside dependent non-type arguments like sizeof(Type). */
8312 static tree
8314 {
8324 }
8326 /* A template declaration can be substituted for a constrained
8327 template template parameter only when the argument is no more
8328 constrained than the parameter. */
8330 static bool
8332 {
8335 /* For now, allow constrained template template arguments
8336 and unconstrained template template parameters. */
8340 /* If the template parameter is constrained, we need to rewrite its
8341 constraints in terms of the ARG's template parameters. This ensures
8342 that all of the template parameter types will have the same depth.
8344 Note that this is only valid when coerce_template_template_parm is
8345 true for the innermost template parameters of PARM and ARG. In other
8346 words, because coercion is successful, this conversion will be valid. */
8349 {
8358 }
8361 }
8363 // Convert a placeholder argument into a binding to the original
8364 // parameter. The original parameter is saved as the TREE_TYPE of
8365 // ARG.
8368 {
8371 }
8373 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
8374 because one of them is dependent. But we need to represent the
8375 conversion for the benefit of cp_tree_equal. */
8377 static tree
8379 {
8380 /* Auto parms get no conversion. */
8383 /* We don't need or want to add this conversion now if we're going to use the
8384 argument for deduction. */
8396 }
8398 /* Convert the indicated template ARG as necessary to match the
8399 indicated template PARM. Returns the converted ARG, or
8400 error_mark_node if the conversion was unsuccessful. Error and
8401 warning messages are issued under control of COMPLAIN. This
8402 conversion is for the Ith parameter in the parameter list. ARGS is
8403 the full set of template arguments deduced so far. */
8405 static tree
8407 tree arg,
8408 tree args,
8409 tsubst_flags_t complain,
8411 tree in_decl)
8412 {
8413 tree orig_arg;
8414 tree val;
8420 /* Trivially convert placeholders. */
8429 {
8430 /* The template argument was the name of some
8431 member function. That's usually
8432 invalid, but static members are OK. In any
8433 case, grab the underlying fields/functions
8434 and issue an error later if required. */
8436 }
8444 /* When determining whether an argument pack expansion is a template,
8445 look at the pattern. */
8449 /* Deal with an injected-class-name used as a template template arg. */
8451 {
8454 {
8464 }
8465 }
8467 is_tmpl_type =
8483 {
8485 {
8489 }
8492 "to refer to a type member of a template parameter, "
8497 typename_type,
8498 complain);
8501 }
8503 {
8505 {
8507 {
8512 {
8513 /* The template argument is a type, but we're expecting
8514 an expression. */
8519 /* [temp.arg]/2: "In a template-argument, an ambiguity
8520 between a type-id and an expression is resolved to a
8521 type-id, regardless of the form of the corresponding
8522 template-parameter." So give the user a clue. */
8525 "for non-type template parameter is treated as "
8527 }
8531 else
8534 }
8535 }
8537 }
8539 {
8541 {
8548 else
8551 }
8553 }
8556 /* We already did the appropriate conversion when packing args. */
8559 {
8561 {
8563 /* The number of argument required is not known yet.
8564 Just accept it for now. */
8566 else
8567 {
8568 /* Strip alias templates that are equivalent to another
8569 template. */
8574 args))
8575 {
8578 /* TEMPLATE_TEMPLATE_PARM node is preferred over
8579 TEMPLATE_DECL. */
8581 {
8586 }
8587 }
8588 else
8589 {
8591 {
8598 }
8601 }
8603 // Check that the constraints are compatible before allowing the
8604 // substitution.
8607 {
8609 {
8615 }
8617 }
8618 }
8619 }
8620 else
8622 /* We only form one instance of each template specialization.
8623 Therefore, if we use a non-canonical variant (i.e., a
8624 typedef), any future messages referring to the type will use
8625 the typedef, which is confusing if those future uses do not
8626 themselves also use the typedef. */
8629 }
8630 else
8631 {
8636 /* We don't have enough levels of args to do any substitution. This
8639 {
8644 }
8645 else
8648 /* Perform array-to-pointer and function-to-pointer conversion
8649 as per [temp.param]/10. */
8655 /* Drop top-level cv-qualifiers on the substituted/deduced type of
8656 this non-type template parameter, as per [temp.param]/6. */
8664 /* We used to call digest_init here. However, digest_init
8665 will report errors, which we don't want when complain
8666 is zero. More importantly, digest_init will try too
8667 hard to convert things: for example, `0' should not be
8668 converted to pointer type at this point according to
8669 the standard. Accepting this is not merely an
8670 extension, since deciding whether or not these
8671 conversions can occur is part of determining which
8672 function template to call, or whether a given explicit
8673 argument specification is valid. */
8675 else
8676 {
8679 }
8690 {
8691 /* Reject template arguments that are references to built-in
8692 functions with no library fallbacks. */
8701 }
8704 {
8705 /* Strip typedefs from the SCOPE_REF. */
8708 complain);
8711 }
8712 }
8715 }
8717 /* Coerces the remaining template arguments in INNER_ARGS (from
8718 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
8719 Returns the coerced argument pack. PARM_IDX is the position of this
8720 parameter in the template parameter list. ARGS is the original
8721 template argument list. */
8722 static tree
8725 tree args,
8726 tree inner_args,
8728 tree new_args,
8730 tree in_decl,
8731 tsubst_flags_t complain)
8732 {
8735 tree packed_args;
8736 tree argument_pack;
8743 {
8744 /* When the template parameter is a non-type template parameter pack
8745 or template template parameter pack whose type or template
8746 parameters use parameter packs, we know exactly how many arguments
8747 we are looking for. Build a vector of the instantiated decls for
8748 these template parameters in PACKED_PARMS. */
8749 /* We can't use make_pack_expansion here because it would interpret a
8750 _DECL as a use rather than a declaration. */
8764 /* If we're doing a partial instantiation of a member template,
8765 verify that all of the types used for the non-type
8766 template parameter pack are, in fact, valid for non-type
8767 template parameters. */
8770 {
8773 {
8778 }
8779 /* We don't know how many args we have yet, just
8780 use the unconverted ones for now. */
8782 }
8785 }
8786 /* Check if we have a placeholder pack, which indicates we're
8787 in the context of a introduction list. In that case we want
8788 to match this pack to the single placeholder. */
8792 {
8795 }
8796 else
8799 /* Convert the remaining arguments, which will be a part of the
8800 parameter pack "parm". */
8803 {
8809 {
8810 /* Once we've packed as many args as we have types, stop. */
8814 /* We don't know how many args we have yet, just
8815 use the unconverted ones for now. */
8817 else
8819 }
8822 {
8825 }
8826 else
8829 in_decl);
8833 }
8837 {
8842 }
8847 else
8848 {
8851 }
8858 }
8860 /* Returns the number of pack expansions in the template argument vector
8861 ARGS. */
8863 static int
8865 {
8870 {
8874 }
8876 }
8878 /* Convert all template arguments to their appropriate types, and
8879 return a vector containing the innermost resulting template
8880 arguments. If any error occurs, return error_mark_node. Error and
8881 warning messages are issued under control of COMPLAIN.
8883 If PARMS represents all template parameters levels, this function
8884 returns a vector of vectors representing all the resulting argument
8885 levels. Note that in this case, only the innermost arguments are
8886 coerced because the outermost ones are supposed to have been coerced
8887 already. Otherwise, if PARMS represents only (the innermost) vector
8888 of parameters, this function returns a vector containing just the
8889 innermost resulting arguments.
8891 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8892 for arguments not specified in ARGS. If REQUIRE_ALL_ARGS is true,
8893 arguments not specified in ARGS must have default arguments which
8894 we'll use to fill in ARGS. */
8896 tree
8898 tree args,
8899 tree in_decl,
8900 tsubst_flags_t complain,
8902 {
8904 tree orig_inner_args;
8905 tree inner_args;
8907 /* When used as a boolean value, indicates whether this is a
8908 variadic template parameter list. Since it's an int, we can also
8909 subtract it from nparms to get the number of non-variadic
8910 parameters. */
8915 /* Adjustment to nparms for fixed parameter packs. */
8920 /* Likewise for parameters with default arguments. */
8928 {
8930 {
8933 }
8935 }
8939 /* Determine if there are any parameter packs or default arguments. */
8941 {
8949 }
8952 /* If there are no parameters that follow a parameter pack, we need to
8953 expand any argument packs so that we can deduce a parameter pack from
8954 some non-packed args followed by an argument pack, as in variadic85.C.
8955 If there are such parameters, we need to leave argument packs intact
8956 so the arguments are assigned properly. This can happen when dealing
8957 with a nested class inside a partial specialization of a class
8958 template, as in variadic92.C, or when deducing a template parameter pack
8959 from a sub-declarator, as in variadic114.C. */
8963 /* Count any pack expansion args. */
8969 && require_all_args
8970 && !variadic_args_p
8973 {
8974 bad_nargs:
8976 {
8978 {
8982 }
8983 else
8990 }
8993 }
8994 /* We can't pass a pack expansion to a non-pack parameter of an alias
8995 template (DR 1430). */
8999 && variadic_args_p
9001 {
9003 {
9005 {
9011 {
9014 "pack expansion argument for non-pack parameter "
9016 else
9018 "pack expansion argument for non-pack parameter "
9022 }
9023 }
9025 found:;
9026 }
9028 }
9030 /* We need to evaluate the template arguments, even though this
9031 template-id may be nested within a "sizeof". */
9032 cp_evaluated ev;
9038 {
9039 tree arg;
9040 tree parm;
9042 /* Get the Ith template parameter. */
9046 {
9049 }
9051 /* Calculate the next argument. */
9054 else
9060 {
9061 /* Some arguments will be placed in the
9062 template parameter pack PARM. */
9069 {
9070 /* We don't know how many args we have yet, just use the
9071 unconverted (and still packed) ones for now. */
9075 }
9079 /* Store this argument. */
9081 {
9082 lost++;
9083 /* We are done with all of the arguments. */
9086 }
9087 else
9088 {
9092 {
9095 }
9096 }
9099 }
9101 {
9103 {
9104 /* "If every valid specialization of a variadic template
9105 requires an empty template parameter pack, the template is
9106 ill-formed, no diagnostic required." So check that the
9107 pattern works with this parameter. */
9112 in_decl);
9114 {
9119 }
9121 /* Recover from missing typename. */
9125 /* We don't know how many args we have yet, just
9126 use the unconverted ones for now. */
9130 }
9131 }
9133 {
9134 /* There must be a default arg in this case. */
9137 /* The position of the first default template argument,
9138 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
9139 Record that. */
9143 }
9144 else
9148 {
9151 }
9153 {
9154 /* This can occur if there was an error in the template
9155 parameter list itself (which we would already have
9156 reported) that we are trying to recover from, e.g., a class
9157 template with a parameter list such as
9158 template<typename..., typename> (cpp0x/variadic150.C). */
9161 /* This can also happen with a fixed parameter pack (71834). */
9164 }
9165 else
9171 lost++;
9174 }
9177 {
9178 /* If we had fixed parameter packs, we didn't know how many arguments we
9179 actually needed earlier; now we do. */
9183 }
9186 {
9187 /* We had some pack expansion arguments that will only work if the packs
9188 are empty, but wait until instantiation time to complain.
9189 See variadic-ttp3.C. */
9191 /* Except that we can't provide empty packs to alias templates or
9192 concepts when there are no corresponding parameters. Basically,
9193 we can get here with this:
9195 template<typename T> concept C = true;
9197 template<typename... Args>
9198 requires C<Args...>
9199 void f();
9201 When parsing C<Args...>, we try to form a concept check of
9202 C<?, Args...>. Without the extra check for substituting an empty
9203 pack past the last parameter, we can accept the check as valid.
9205 FIXME: This may be valid for alias templates (but I doubt it).
9207 FIXME: The error could be better also. */
9209 {
9214 }
9225 }
9228 {
9231 }
9238 }
9240 /* Returns true if T is a wrapper to make a C++20 template parameter
9241 object const. */
9243 static bool
9245 {
9251 }
9253 /* Returns 1 if template args OT and NT are equivalent. */
9255 int
9257 {
9270 /* DR 1558: Don't treat an alias template specialization with dependent
9271 arguments as equivalent to its underlying type when used as a template
9272 argument; we need them to be distinct so that we substitute into the
9273 specialization arguments at instantiation time. And aliases can't be
9274 equivalent without being ==, so we don't need to look any deeper.
9276 During partial ordering, however, we need to treat them normally so we can
9277 order uses of the same alias with different cv-qualification (79960). */
9283 /* For member templates */
9296 {
9300 }
9301 else
9302 {
9303 /* Try to treat a template non-type argument that has been converted
9304 to the parameter type as equivalent to one that hasn't yet. */
9318 }
9319 }
9321 /* Returns true iff the OLDARGS and NEWARGS are in fact identical sets of
9322 template arguments. Returns false otherwise, and updates OLDARG_PTR and
9323 NEWARG_PTR with the offending arguments if they are non-NULL. */
9325 bool
9329 {
9340 {
9345 {
9351 }
9352 }
9354 }
9358 {
9360 }
9362 /* Implement a freelist interface for objects of type T.
9364 Head is a separate object, rather than a regular member, so that we
9365 can define it as a GTY deletable pointer, which is highly
9366 desirable. A data member could be declared that way, but then the
9367 containing object would implicitly get GTY((user)), which would
9368 prevent us from instantiating freelists as global objects.
9369 Although this way we can create freelist global objects, they're
9370 such thin wrappers that instantiating temporaries at every use
9371 loses nothing and saves permanent storage for the freelist object.
9373 Member functions next, anew, poison and reinit have default
9374 implementations that work for most of the types we're interested
9375 in, but if they don't work for some type, they should be explicitly
9376 specialized. See the comments before them for requirements, and
9377 the example specializations for the tree_list_freelist. */
9379 class freelist
9380 {
9381 /* Return the next object in a chain. We could just do type
9382 punning, but if we access the object with its underlying type, we
9383 avoid strict-aliasing trouble. This needs only work between
9384 poison and reinit. */
9387 /* Return a newly allocated, uninitialized or minimally-initialized
9388 object of type T. Any initialization performed by anew should
9389 either remain across the life of the object and the execution of
9390 poison, or be redone by reinit. */
9393 /* Optionally scribble all over the bits holding the object, so that
9394 they become (mostly?) uninitialized memory. This is called while
9395 preparing to make the object part of the free list. */
9400 #ifdef ENABLE_GC_CHECKING
9401 /* Poison the data, to indicate the data is garbage. */
9404 #endif
9405 /* Let valgrind know the object is free. */
9408 /* Let valgrind know the next portion of the object is available,
9409 but uninitialized. */
9411 }
9413 /* Bring an object that underwent at least one lifecycle after anew
9414 and before the most recent free and poison, back to a usable
9415 state, reinitializing whatever is needed for it to be
9416 functionally equivalent to an object just allocated and returned
9417 by anew. This may poison or clear the next field, used by
9418 freelist housekeeping after poison was called. */
9422 #ifdef ENABLE_GC_CHECKING
9424 #endif
9425 /* Let valgrind know the entire object is available, but
9426 uninitialized. */
9428 }
9430 /* Reference a GTY-deletable pointer that points to the first object
9431 in the free list proper. */
9434 /* Construct a freelist object chaining objects off of HEAD. */
9437 /* Add OBJ to the free object list. The former head becomes OBJ's
9438 successor. */
9440 {
9444 }
9446 /* Take an object from the free list, if one is available, or
9447 allocate a new one. Objects taken from the free list should be
9448 regarded as filled with garbage, except for bits that are
9449 configured to be preserved across free and alloc. */
9451 {
9453 {
9458 }
9459 else
9461 }
9462 };
9464 /* Explicitly specialize the interfaces for freelist<tree_node>: we
9465 want to allocate a TREE_LIST using the usual interface, and ensure
9466 TREE_CHAIN remains functional. Alas, we have to duplicate a bit of
9467 build_tree_list logic in reinit, so this could go out of sync. */
9471 {
9473 }
9475 inline tree
9477 {
9479 }
9483 {
9489 #ifdef ENABLE_GC_CHECKING
9492 /* Poison the data, to indicate the data is garbage. */
9495 #endif
9496 /* Let valgrind know the object is free. */
9498 /* But we still want to use the TREE_CODE and TREE_CHAIN parts. */
9502 #ifdef ENABLE_GC_CHECKING
9504 /* Keep TREE_CHAIN functional. */
9506 #else
9508 #endif
9509 }
9513 {
9516 #ifdef ENABLE_GC_CHECKING
9520 #endif
9522 /* Let valgrind know the entire object is available, but
9523 uninitialized. */
9526 #ifdef ENABLE_GC_CHECKING
9528 #else
9530 #endif
9531 }
9533 /* Point to the first object in the TREE_LIST freelist. */
9535 /* Return the/an actual TREE_LIST freelist. */
9538 {
9540 }
9542 /* Point to the first object in the tinst_level freelist. */
9544 /* Return the/an actual tinst_level freelist. */
9547 {
9549 }
9551 /* Point to the first object in the pending_template freelist. */
9553 /* Return the/an actual pending_template freelist. */
9556 {
9558 }
9560 /* Build the TREE_LIST object out of a split list, store it
9561 permanently, and return it. */
9562 tree
9564 {
9573 }
9577 /* Increment OBJ's refcount unless it is already infinite. */
9580 {
9584 }
9586 /* Release storage for OBJ and node, if it's a TREE_LIST. */
9587 void
9589 {
9593 }
9595 /* Decrement OBJ's refcount if not infinite. If it reaches zero, release
9596 OBJ's DECL and OBJ, and start over with the tinst_level object that
9597 used to be referenced by OBJ's NEXT. */
9598 static void
9600 {
9604 {
9608 }
9609 }
9611 /* Modify PTR so that it points to OBJ, adjusting the refcounts of OBJ
9612 and of the former PTR. Omitting the second argument is equivalent
9613 to passing (T*)NULL; this is allowed because passing the
9614 zero-valued integral constant NULL confuses type deduction and/or
9615 overload resolution. */
9617 static void
9619 {
9623 }
9625 static void
9627 {
9637 /* We are called both from instantiate_decl, where we've already had a
9638 tinst_level pushed, and instantiate_template, where we haven't.
9639 Compensate. */
9641 level = !current_tinst_level
9653 else
9662 }
9665 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
9666 ARGLIST. Valid choices for FNS are given in the cp-tree.def
9667 documentation for TEMPLATE_ID_EXPR. */
9669 tree
9671 {
9678 {
9681 }
9684 {
9687 unknown_type_node,
9689 arglist);
9691 }
9694 }
9696 /* Within the scope of a template class S<T>, the name S gets bound
9697 (in build_self_reference) to a TYPE_DECL for the class, not a
9698 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
9699 or one of its enclosing classes, and that type is a template,
9700 return the associated TEMPLATE_DECL. Otherwise, the original
9701 DECL is returned.
9703 Also handle the case when DECL is a TREE_LIST of ambiguous
9704 injected-class-names from different bases. */
9706 tree
9708 {
9712 /* DR 176: A lookup that finds an injected-class-name (10.2
9713 [class.member.lookup]) can result in an ambiguity in certain cases
9714 (for example, if it is found in more than one base class). If all of
9715 the injected-class-names that are found refer to specializations of
9716 the same class template, and if the name is followed by a
9717 template-argument-list, the reference refers to the class template
9718 itself and not a specialization thereof, and is not ambiguous. */
9720 {
9723 {
9729 }
9732 else
9734 }
9740 }
9742 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
9743 parameters, find the desired type.
9745 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
9747 IN_DECL, if non-NULL, is the template declaration we are trying to
9748 instantiate.
9750 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
9751 the class we are looking up.
9753 Issue error and warning messages under control of COMPLAIN.
9755 If the template class is really a local class in a template
9756 function, then the FUNCTION_CONTEXT is the function in which it is
9757 being instantiated.
9759 ??? Note that this function is currently called *twice* for each
9760 template-id: the first time from the parser, while creating the
9761 incomplete type (finish_template_type), and the second type during the
9762 real instantiation (instantiate_template_class). This is surely something
9763 that we want to avoid. It also causes some problems with argument
9764 coercion (see convert_nontype_argument for more information on this). */
9766 tree
9769 {
9773 tree t;
9776 spec_entry elt;
9777 hashval_t hash;
9780 {
9784 else
9785 {
9792 }
9793 }
9795 {
9798 /* If we are declaring a constructor, say A<T>::A<T>, we will get
9799 an implicit typename for the second A. Deal with it. */
9804 {
9807 }
9808 }
9811 {
9814 }
9816 {
9819 }
9821 {
9824 }
9826 /* Issue an error message if we didn't find a template. */
9828 {
9832 }
9835 /* Make sure it's a user visible template, if it was named by
9836 the user. */
9839 {
9841 {
9845 }
9847 }
9851 /* An alias that just changes the name of a template is equivalent to the
9852 other template, so if any of the arguments are pack expansions, strip
9853 the alias to avoid problems with a pack expansion passed to a non-pack
9854 alias template parameter (DR 1430). */
9859 {
9860 tree parm;
9869 }
9870 else
9871 {
9873 tree gen_tmpl;
9874 tree type_decl;
9882 /* An error occurred while building the template TEMPL, and a
9883 diagnostic has most certainly been emitted for that
9884 already. Let's propagate that error. */
9896 {
9897 /* We've been given an incomplete set of template arguments.
9898 For example, given:
9900 template <class T> struct S1 {
9901 template <class U> struct S2 {};
9902 template <class U> struct S2<U*> {};
9903 };
9905 we will be called with an ARGLIST of `U*', but the
9906 TEMPLATE will be `template <class T> template
9907 <class U> struct S1<T>::S2'. We must fill in the missing
9908 arguments. */
9912 }
9914 /* Now we should have enough arguments. */
9917 /* From here on, we're only interested in the most general
9918 template. */
9920 /* Shortcut looking up the current class scope again. */
9927 /* Calculate the BOUND_ARGS. These will be the args that are
9928 actually tsubst'd into the definition to create the
9929 instantiation. */
9933 /* We were unable to bind the arguments. */
9936 /* In the scope of a template class, explicit references to the
9937 template class refer to the type of the template, not any
9938 instantiation of it. For example, in:
9940 template <class T> class C { void f(C<T>); }
9942 the `C<T>' is just the same as `C'. Outside of the
9943 class, however, such a reference is an instantiation. */
9947 {
9952 }
9954 /* If we already have this specialization, return it. */
9964 /* If the template's constraints are not satisfied,
9965 then we cannot form a valid type.
9967 Note that the check is deferred until after the hash
9968 lookup. This prevents redundant checks on previously
9969 instantiated specializations. */
9973 {
9975 {
9976 auto_diagnostic_group d;
9979 }
9981 }
9985 /* If the deduced arguments are invalid, then the binding
9986 failed. */
9990 complain))
9997 /* This occurs when the user has tried to define a tagged type
9998 in a scope that forbids it. We emitted an error during the
9999 parse. We didn't complete the bail out then, so here we
10000 are. */
10005 {
10007 /* If the context of the partially instantiated template is
10008 already non-dependent, then we might as well use it. */
10010 else
10011 {
10014 /* Try completing the enclosing context if it's not already so. */
10017 {
10020 {
10021 /* Completion could have caused us to register the desired
10022 specialization already, so check the table again. */
10026 }
10027 }
10028 }
10029 }
10030 else
10039 /* Create the type. */
10041 {
10042 /* The user referred to a specialization of an alias
10043 template represented by GEN_TMPL.
10045 [temp.alias]/2 says:
10047 When a template-id refers to the specialization of an
10048 alias template, it is equivalent to the associated
10049 type obtained by substitution of its
10050 template-arguments for the template-parameters in the
10051 type-id of the alias template. */
10054 /* Note that the call above (by indirectly calling
10055 register_specialization in tsubst_decl) registers the
10056 TYPE_DECL representing the specialization of the alias
10057 template. So next time someone substitutes ARGLIST for
10058 the template parms into the alias template (GEN_TMPL),
10059 she'll get that TYPE_DECL back. */
10063 }
10065 {
10067 {
10078 }
10079 else
10080 {
10081 /* We don't want to call start_enum for this type, since
10082 the values for the enumeration constants may involve
10083 template parameters. And, no one should be interested
10084 in the enumeration constants for such a type. */
10087 }
10091 }
10093 {
10094 /* Lambda closures are regenerated in tsubst_lambda_expr, not
10095 instantiated here. */
10103 /* A local class. Make sure the decl gets registered properly. */
10110 /* This instantiation is another name for the primary
10111 template type. Set the TYPE_CANONICAL field
10112 appropriately. */
10116 }
10117 else
10120 /* If we called start_enum or pushtag above, this information
10121 will already be set up. */
10124 {
10131 }
10134 /* Although GEN_TMPL is the TEMPLATE_DECL, it has the same value
10135 of export flag. We want to propagate this because it might
10136 be a friend declaration that pushes a new hidden binding. */
10140 {
10146 {
10149 }
10150 }
10154 {
10158 {
10159 tree attributes
10167 }
10168 }
10170 /* Let's consider the explicit specialization of a member
10171 of a class template specialization that is implicitly instantiated,
10172 e.g.:
10173 template<class T>
10174 struct S
10175 {
10176 template<class U> struct M {}; //#0
10177 };
10179 template<>
10180 template<>
10181 struct S<int>::M<char> //#1
10182 {
10183 int i;
10184 };
10185 [temp.expl.spec]/4 says this is valid.
10187 In this case, when we write:
10188 S<int>::M<char> m;
10190 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
10191 the one of #0.
10193 When we encounter #1, we want to store the partial instantiation
10194 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
10196 For all cases other than this "explicit specialization of member of a
10197 class template", we just want to store the most general template into
10198 the CLASSTYPE_TI_TEMPLATE of M.
10200 This case of "explicit specialization of member of a class template"
10201 only happens when:
10202 1/ the enclosing class is an instantiation of, and therefore not
10203 the same as, the context of the most general template, and
10204 2/ we aren't looking at the partial instantiation itself, i.e.
10205 the innermost arguments are not the same as the innermost parms of
10206 the most general template.
10208 So it's only when 1/ and 2/ happens that we want to use the partial
10209 instantiation of the member template in lieu of its most general
10210 template. */
10214 /* the enclosing class must be an instantiation... */
10217 {
10221 tree partial_inst_args =
10228 use_partial_inst_tmpl =
10229 /*...and we must not be looking at the partial instantiation
10230 itself. */
10232 partial_inst_args);
10233 }
10236 /* This case is easy; there are no member templates involved. */
10238 else
10239 {
10240 /* This is a full instantiation of a member template. Find
10241 the partial instantiation of which this is an instance. */
10243 /* Temporarily reduce by one the number of levels in the ARGLIST
10244 so as to avoid comparing the last set of arguments. */
10246 /* We don't use COMPLAIN in the following call because this isn't
10247 the immediate context of deduction. For instance, tf_partial
10248 could be set here as we might be at the beginning of template
10249 argument deduction when any explicitly specified template
10250 arguments are substituted into the function type. tf_partial
10251 could lead into trouble because we wouldn't find the partial
10252 instantiation that might have been created outside tf_partial
10253 context, because the levels of template parameters wouldn't
10254 match, because in a tf_partial context, tsubst doesn't reduce
10255 TEMPLATE_PARM_LEVEL. */
10258 /* FOUND is either a proper class type, or an alias
10259 template specialization. In the later case, it's a
10260 TYPE_DECL, resulting from the substituting of arguments
10261 for parameters in the TYPE_DECL of the alias template
10262 done earlier. So be careful while getting the template
10263 of FOUND. */
10265 ? found
10272 {
10273 /* If this partial instantiation is specialized, we want to
10274 use it for hash table lookup. */
10278 }
10279 }
10281 /* Build template info for the new specialization. */
10291 /* Note this use of the partial instantiation so we can check it
10292 later in maybe_process_partial_specialization. */
10300 /* Now that the type has been registered on the instantiations
10301 list, we set up the enumerators. Because the enumeration
10302 constants may involve the enumeration type itself, we make
10303 sure to register the type first, and then create the
10304 constants. That way, doing tsubst_expr for the enumeration
10305 constants won't result in recursive calls here; we'll find
10306 the instantiation and exit above. */
10310 /* If the type makes use of template parameters, the
10311 code that generates debugging information will crash. */
10314 /* Possibly limit visibility based on template args. */
10321 }
10322 }
10324 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
10326 tree
10328 {
10332 /* The type of the expression is NULL_TREE since the template-id could refer
10333 to an explicit or partial specialization. */
10335 }
10337 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR if it's
10338 not dependent. */
10340 tree
10342 {
10346 /* If the template or arguments are dependent, then we
10347 can't resolve the TEMPLATE_ID_EXPR yet. */
10358 {
10360 {
10361 auto_diagnostic_group d;
10364 }
10366 }
10369 }
10371 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
10372 TARGS template args, and instantiate it if it's not dependent. */
10374 tree
10376 tsubst_flags_t complain)
10377 {
10379 /* We may be called while doing a partial substitution, but the
10380 type of the variable template may be auto, in which case we
10381 will call do_auto_deduction in mark_used (which clears tf_partial)
10382 and the auto must be properly reduced at that time for the
10383 deduction to work. */
10388 }
10390 /* If the set of template parameters PARMS contains a template parameter
10391 at the given LEVEL and INDEX, then return this parameter. Otherwise
10392 return NULL_TREE. */
10394 static tree
10396 {
10405 }
10407 /* Return the TREE_LIST for the template parameter from PARMS that positionally
10408 corresponds to the template parameter PARM, or else return NULL_TREE. */
10410 static tree
10412 {
10416 }
10418 /* As above, but pull out the actual parameter. */
10420 static tree
10422 {
10428 /* As in template_parm_to_arg. */
10431 else
10436 }
10437 \f
10438 struct pair_fn_data
10439 {
10440 tree_fn_t fn;
10441 tree_fn_t any_fn;
10443 /* True when we should also visit template parameters that occur in
10444 non-deduced contexts. */
10447 };
10449 /* Called from for_each_template_parm via walk_tree. */
10451 static tree
10453 {
10460 #define WALK_SUBTREE(NODE) \
10461 do \
10462 { \
10463 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
10464 pfd->include_nondeduced_p, \
10465 pfd->any_fn); \
10466 if (result) goto out; \
10467 } \
10468 while (0)
10478 {
10482 /* Fall through. */
10488 else
10498 /* Since we're not going to walk subtrees, we have to do this
10499 explicitly here. */
10501 /* Fall through. */
10504 /* Check the return type. */
10507 /* Check the parameter types. Since default arguments are not
10508 instantiated until they are needed, the TYPE_ARG_TYPES may
10509 contain expressions that involve template parameters. But,
10510 no-one should be looking at them yet. And, once they're
10511 instantiated, they don't contain template parameters, so
10512 there's no point in looking at them then, either. */
10513 {
10514 tree parm;
10519 /* Since we've already handled the TYPE_ARG_TYPES, we don't
10520 want walk_tree walking into them itself. */
10522 }
10525 {
10529 }
10545 {
10548 }
10571 /* Record template parameters such as `T' inside `TT<T>'. */
10573 /* Fall through. */
10585 /* A template template parameter is encountered. */
10589 /* Already substituted template template parameter */
10594 /* A template-id in a TYPENAME_TYPE might be a deduced context after
10595 partial instantiation. */
10602 /* If there's no type, then this thing must be some expression
10603 involving template parameters. */
10613 /* These are non-deduced contexts. */
10635 }
10637 #undef WALK_SUBTREE
10639 /* We didn't find any template parameters we liked. */
10640 out:
10642 }
10644 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
10645 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
10646 call FN with the parameter and the DATA.
10647 If FN returns nonzero, the iteration is terminated, and
10648 for_each_template_parm returns 1. Otherwise, the iteration
10649 continues. If FN never returns a nonzero value, the value
10650 returned by for_each_template_parm is 0. If FN is NULL, it is
10651 considered to be the function which always returns 1.
10653 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
10654 parameters that occur in non-deduced contexts. When false, only
10655 visits those template parameters that can be deduced. */
10657 static tree
10661 tree_fn_t any_fn)
10662 {
10664 tree result;
10666 /* Set up. */
10672 /* Walk the tree. (Conceptually, we would like to walk without
10673 duplicates, but for_each_template_parm_r recursively calls
10674 for_each_template_parm, so we would need to reorganize a fair
10675 bit to use walk_tree_without_duplicates, so we keep our own
10676 visited list.) */
10679 else
10682 for_each_template_parm_r,
10686 /* Clean up. */
10688 {
10691 }
10694 }
10696 struct find_template_parameter_info
10697 {
10701 {}
10707 tree ctx_parms;
10714 };
10716 /* Appends the declaration of T to the list in DATA. */
10718 static int
10720 {
10723 /* Template parameters declared within the expression are not part of
10724 the parameter mapping. For example, in this concept:
10726 template<typename T>
10727 concept C = requires { <expr> } -> same_as<int>;
10729 the return specifier same_as<int> declares a new decltype parameter
10730 that must not be part of the parameter mapping. The same is true
10731 for generic lambda parameters, lambda template parameters, etc. */
10739 /* We want the underlying TEMPLATE_TEMPLATE_PARM, not the
10740 BOUND_TEMPLATE_TEMPLATE_PARM itself. */
10743 /* This template parameter might be an argument to a cached dependent
10744 specalization that was formed earlier inside some other template, in
10745 which case the parameter is not among the ones that are in-scope.
10746 Look in CTX_PARMS to find the corresponding in-scope template
10747 parameter, and use it instead. */
10751 /* Arguments like const T yield parameters like const T. This means that
10752 a template-id like X<T, const T> would yield two distinct parameters:
10753 T and const T. Adjust types to their unqualified versions. */
10757 {
10758 /* Append T to PARM_LIST. */
10762 }
10764 /* Verify the parameter we found has a valid index. */
10766 {
10772 }
10775 }
10777 /* Ensure that we recursively examine certain terms that are not normally
10778 visited in for_each_template_parm_r. */
10780 static int
10782 {
10785 #define WALK_SUBTREE(NODE) \
10786 do \
10787 { \
10788 for_each_template_parm (NODE, keep_template_parm, data, \
10789 &ftpi->visited, true, \
10790 any_template_parm_r); \
10791 } \
10792 while (0)
10794 /* A mention of a member alias/typedef is a use of all of its template
10795 arguments, including those from the enclosing class, so we don't use
10796 alias_template_specialization_p here. */
10802 {
10804 /* Type constraints of a placeholder type may contain parameters. */
10811 /* Search through references to variable templates. */
10821 /* If T is a member template that shares template parameters with
10822 ctx_parms, we need to mark all those parameters for mapping.
10823 To that end, it should suffice to just walk the DECL_CONTEXT of
10824 the template (assuming the template is not overly general). */
10829 {
10830 /* Look in the parms and body. */
10834 }
10839 /* The conversion-type-id of a conversion operator may be dependent. */
10850 }
10852 /* Keep walking. */
10854 }
10856 /* Look through T for template parameters. */
10858 tree
10860 {
10863 any_template_parm_r);
10864 }
10866 /* As above, but also recursively look into the default arguments of template
10867 parameters we found. Used for alias CTAD. */
10869 tree
10871 {
10874 /* Since newly found parms are added to the end of the list, we
10875 can just walk it until we reach the end. */
10877 {
10882 }
10884 }
10886 /* True if PARM was found by a previous call to find_in. PARM can be a
10887 TREE_LIST, a DECL_TEMPLATE_PARM_P, or a TEMPLATE_PARM_P. */
10889 bool
10891 {
10896 else
10900 }
10902 /* Returns a list of unique template parameters found within T, where CTX_PARMS
10903 are the template parameters in scope. */
10905 tree
10907 {
10914 }
10916 /* Returns true if T depends on any template parameter. */
10918 bool
10920 {
10924 /* Namespaces can't depend on any template parameters. */
10940 else
10942 }
10944 /* Returns true if T depends on any template parameter with level LEVEL. */
10946 bool
10948 {
10951 }
10953 /* Returns true if the signature of DECL depends on any template parameter from
10954 its enclosing class. */
10956 static bool
10958 {
10967 {
10970 {
10975 template_parm_outer_level,
10985 }
10986 }
10990 }
10992 /* Returns true if the constraints of DECL depend on any template parameters
10993 from its enclosing scope. */
10995 bool
10997 {
11008 }
11010 /* Returns TRUE iff INST is an instantiation we don't need to do in an
11011 ill-formed translation unit, i.e. a variable or function that isn't
11012 usable in a constant expression. */
11016 {
11022 }
11024 /* Returns TRUE iff we should refuse to instantiate DECL because it's
11025 neglectable and instantiated from within an erroneous instantiation. */
11027 static bool
11029 {
11035 /* Avoid instantiating members of an ill-formed class. */
11036 bool refuse
11041 {
11046 }
11049 {
11050 /* Don't warn about it not being defined. */
11052 tree clone;
11055 }
11057 }
11065 /* We're starting to instantiate D; record the template instantiation context
11066 at LOC for diagnostics and to restore it later. */
11068 bool
11070 {
11074 {
11075 /* Tell error.cc not to try to instantiate any templates. */
11078 "template instantiation depth exceeds maximum of %d"
11080 max_tinst_depth);
11082 }
11084 /* If the current instantiation caused problems, don't let it instantiate
11085 anything else. Do allow deduction substitution and decls usable in
11086 constant expressions. */
11088 {
11089 /* Avoid no_linkage_errors and unused function (and all other)
11090 warnings for this decl. */
11093 }
11095 /* When not -quiet, dump template instantiations other than functions, since
11096 announce_function will take care of those. */
11118 }
11120 /* We're starting substitution of TMPL<ARGS>; record the template
11121 substitution context for diagnostics and to restore it later. */
11123 bool
11125 {
11127 }
11129 /* We're starting to instantiate D; record INPUT_LOCATION and the
11130 template instantiation context for diagnostics and to restore it
11131 later. */
11133 bool
11135 {
11137 }
11139 /* Likewise, but record LOC as the program location. */
11141 bool
11143 {
11146 }
11148 /* We're done instantiating this template; return to the instantiation
11149 context. */
11151 void
11153 {
11154 /* Restore the filename and line number stashed away when we started
11155 this instantiation. */
11159 }
11161 /* We're instantiating a deferred template; restore the template
11162 instantiation context in which the instantiation was requested, which
11163 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
11165 static tree
11167 {
11179 }
11181 /* Returns the TINST_LEVEL which gives the original instantiation
11182 context. */
11186 {
11192 }
11194 /* True iff T is a friend function declaration that is not itself a template
11195 and is not defined in a class template. */
11197 bool
11199 {
11202 {
11206 /* DECL_FRIEND_CONTEXT is set for a friend defined in class. */
11209 /* Non-templated friends in a class template are still represented with a
11210 TEMPLATE_DECL; check that its primary template is the befriending
11211 class. Note that DECL_PRIMARY_TEMPLATE is null for
11212 template <class T> friend A<T>::f(); */
11216 }
11217 else
11219 }
11221 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
11222 vector of template arguments, as for tsubst.
11224 Returns an appropriate tsubst'd friend declaration. */
11226 static tree
11228 {
11229 tree new_friend;
11234 /* This was a friend declared with an explicit template
11235 argument list, e.g.:
11237 friend void f<>(T);
11239 to indicate that f was a template instantiation, not a new
11240 function declaration. Now, we have to figure out what
11241 instantiation of what template. */
11242 {
11244 tree new_args;
11245 tree tmpl;
11248 /* Friend functions are looked up in the containing namespace scope.
11249 We must enter that scope, to avoid finding member functions of the
11250 current class with same name. */
11264 tsk_none);
11266 }
11272 /* The NEW_FRIEND will look like an instantiation, to the
11273 compiler, but is not an instantiation from the point of view of
11274 the language. For example, we might have had:
11276 template <class T> struct S {
11277 template <class U> friend void f(T, U);
11278 };
11280 Then, in S<int>, template <class U> void f(int, U) is not an
11281 instantiation of anything. */
11285 {
11291 /* Substitute TEMPLATE_PARMS_CONSTRAINTS so that parameter levels will
11292 match in decls_match. */
11297 {
11299 /* As well as each TEMPLATE_PARM_CONSTRAINTS. */
11301 tf_warning_or_error);
11302 }
11303 }
11305 /* The mangled name for the NEW_FRIEND is incorrect. The function
11306 is not a template instantiation and should not be mangled like
11307 one. Therefore, we forget the mangling here; we'll recompute it
11308 later if we need it. */
11310 {
11313 }
11316 {
11317 tree old_decl;
11318 tree ns;
11320 /* We must save some information from NEW_FRIEND before calling
11321 duplicate decls since that function will free NEW_FRIEND if
11322 possible. */
11326 (new_friend_template_info
11333 {
11334 /* This declaration is a `primary' template. */
11339 }
11341 /* Only define a constrained hidden friend when satisfied. */
11344 /* Inside pushdecl_namespace_level, we will push into the
11345 current namespace. However, the friend function should go
11346 into the namespace of the template. */
11356 {
11357 /* This new friend declaration matched an existing
11358 declaration. For example, given:
11360 template <class T> void f(T);
11361 template <class U> class C {
11362 template <class T> friend void f(T) {}
11363 };
11365 the friend declaration actually provides the definition
11366 of `f', once C has been instantiated for some type. So,
11367 old_decl will be the out-of-class template declaration,
11368 while new_friend is the in-class definition.
11370 But, if `f' was called before this point, the
11371 instantiation of `f' will have DECL_TI_ARGS corresponding
11372 to `T' but not to `U', references to which might appear
11373 in the definition of `f'. Previously, the most general
11374 template for an instantiation of `f' was the out-of-class
11375 version; now it is the in-class version. Therefore, we
11376 run through all specialization of `f', adding to their
11377 DECL_TI_ARGS appropriately. In particular, they need a
11378 new set of outer arguments, corresponding to the
11379 arguments for this class instantiation.
11381 The same situation can arise with something like this:
11383 friend void f(int);
11384 template <class T> class C {
11385 friend void f(T) {}
11386 };
11388 when `C<int>' is instantiated. Now, `f(int)' is defined
11389 in the class. */
11392 /* On the other hand, if the in-class declaration does
11393 *not* provide a definition, then we don't want to alter
11394 existing definitions. We can just leave everything
11395 alone. */
11396 ;
11397 else
11398 {
11402 /* Overwrite whatever template info was there before, if
11403 any, with the new template information pertaining to
11404 the declaration. */
11408 {
11409 /* We should have called reregister_specialization in
11410 duplicate_decls. */
11415 /* Instantiate it if the global has already been used. */
11419 }
11420 else
11421 {
11422 tree t;
11424 /* Indicate that the old function template is a partial
11425 instantiation. */
11433 /* Reassign any specializations already in the hash table
11434 to the new more general template, and add the
11435 additional template args. */
11439 {
11441 spec_entry elt;
11453 register_specialization
11456 }
11458 }
11459 }
11461 /* The information from NEW_FRIEND has been merged into OLD_DECL
11462 by duplicate_decls. */
11464 }
11466 /* We've just introduced a namespace-scope function in the purview
11467 without necessarily having opened the enclosing namespace, so
11468 make sure the namespace is in the purview now too. */
11473 }
11474 else
11475 {
11479 /* In the code
11480 template <class T> class C {
11481 template <class U> friend void C1<U>::f (); // case 1
11482 friend void C2<T>::f (); // case 2
11483 };
11484 we only need to make sure CONTEXT is a complete type for
11485 case 2. To distinguish between the two cases, we note that
11486 CONTEXT of case 1 remains dependent type after tsubst while
11487 this isn't true for case 2. */
11497 {
11499 /* do_friend adds the TEMPLATE_DECL for any member friend
11500 template even if it isn't a member template, i.e.
11501 template <class T> friend A<T>::f();
11502 Look through it in that case. */
11506 /* Check to see that the declaration is really present, and,
11507 possibly obtain an improved declaration. */
11512 }
11513 }
11516 }
11518 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
11519 template arguments, as for tsubst.
11521 Returns an appropriate tsubst'd friend type or error_mark_node on
11522 failure. */
11524 static tree
11526 {
11527 tree tmpl;
11530 {
11533 }
11538 else
11539 {
11542 }
11548 {
11549 /* The friend template has already been declared. Just
11550 check to see that the declarations match, and install any new
11551 default parameters. We must tsubst the default parameters,
11552 of course. We only need the innermost template parameters
11553 because that is all that redeclare_class_template will look
11554 at. */
11557 {
11561 tf_warning_or_error);
11571 }
11572 }
11573 else
11574 {
11575 /* The friend template has not already been declared. In this
11576 case, the instantiation of the template class will cause the
11577 injection of this template into the namespace scope. */
11581 {
11582 /* The new TMPL is not an instantiation of anything, so we
11583 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
11584 for the new type because that is supposed to be the
11585 corresponding template decl, i.e., TMPL. */
11592 /* Substitute into and set the constraints on the new declaration. */
11594 {
11602 }
11604 /* Inject this template into the enclosing namspace scope. */
11606 }
11607 }
11611 else
11615 }
11617 /* Returns zero if TYPE cannot be completed later due to circularity.
11618 Otherwise returns one. */
11620 static int
11622 {
11632 else
11634 }
11639 /* Instantiate the contract statement. */
11641 static tree
11643 tree in_decl)
11644 {
11650 /* Rebuild the result variable. */
11652 {
11660 /* Make sure the postcondition is valid. */
11666 /* Make the variable available for lookup. */
11668 }
11670 /* Instantiate the condition. If the return type is undeduced, process
11671 the expression as if inside a template to avoid spurious type errors. */
11681 /* And the comment. */
11686 }
11688 /* Update T by instantiating its contract attribute. */
11690 static void
11693 {
11694 /* For non-specializations, adjust the current declaration to the most general
11695 version of in_decl. Because we defer the instantiation of contracts as long
11696 as possible, they are still written in terms of the parameters (and return
11697 type) of the most general template. */
11704 /* Get the contract to be instantiated. */
11707 /* Use the complete set of template arguments for instantiation. The
11708 contract may not have been instantiated and still refer to outer levels
11709 of template parameters. */
11712 /* For member functions, make this available for semantic analysis. */
11716 {
11720 }
11727 /* Rebuild the attribute. */
11729 }
11731 /* Rebuild the attribute list for DECL, substituting into contracts
11732 as needed. */
11734 void
11736 {
11739 {
11742 }
11744 }
11746 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
11747 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
11749 static tree
11752 {
11755 /* Note that contract attributes are never substituted from this function.
11756 Their instantiation is triggered by regenerate_from_template_decl when
11757 we instantiate the body of the function. */
11765 {
11772 clauses
11776 else
11778 }
11782 {
11793 {
11797 {
11799 {
11807 }
11808 else
11809 {
11813 {
11814 bool allow_string
11826 {
11827 location_t loc
11829 match_loc);
11835 "integer expression or string "
11837 else
11841 }
11844 {
11845 location_t loc
11847 match_loc);
11851 }
11853 }
11854 }
11855 }
11856 }
11858 }
11859 /* If the first attribute argument is an identifier, don't
11860 pass it through tsubst. Attributes like mode, format,
11861 cleanup and several target specific attributes expect it
11862 unmodified. */
11864 {
11865 tree chain
11869 }
11871 {
11872 /* An attribute pack expansion. */
11881 {
11885 }
11887 }
11888 else
11896 }
11898 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
11899 unchanged or a new TREE_LIST chain. */
11901 static tree
11904 {
11909 {
11913 }
11917 {
11920 {
11923 {
11929 }
11930 }
11932 }
11935 }
11937 /* Apply any attributes which had to be deferred until instantiation
11938 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
11939 ARGS, COMPLAIN, IN_DECL are as tsubst. Returns true normally,
11940 false on error. */
11942 static bool
11945 {
11946 tree t;
11953 {
11957 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
11958 to our attributes parameter. */
11960 }
11961 else
11962 {
11964 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
11965 lookup_template_class_1, and should be preserved. */
11969 }
11971 /* save_template_attributes puts the dependent attributes at the beginning of
11972 the list; find the non-dependent ones. */
11978 /* Apply any non-dependent attributes. */
11984 /* And then any dependent ones. */
11988 {
11993 {
11996 }
11999 }
12001 /* cplus_decl_attributes can add some attributes implicitly. For templates,
12002 those attributes should have been added already when those templates were
12003 parsed, and shouldn't be added based on from which context they are
12004 first time instantiated. */
12007 optimization_default_node);
12010 NULL);
12016 }
12018 /* The template TMPL is being instantiated with the template arguments TARGS.
12019 Perform the access checks that we deferred when parsing the template. */
12021 static void
12023 {
12033 {
12041 /* Make access check error messages point to the location
12042 of the use of the typedef. */
12046 }
12047 }
12049 tree
12051 {
12055 tree typedecl;
12056 tree pbinfo;
12057 tree base_list;
12059 tree fn_context;
12069 /* Figure out which template is being instantiated. */
12073 /* Mark the type as in the process of being defined. */
12076 /* We may be in the middle of deferred access check. Disable
12077 it now. */
12080 /* Determine what specialization of the original template to
12081 instantiate. */
12086 {
12087 /* This TYPE is actually an instantiation of a partial
12088 specialization. We replace the innermost set of ARGS with
12089 the arguments appropriate for substitution. For example,
12090 given:
12092 template <class T> struct S {};
12093 template <class T> struct S<T*> {};
12095 and supposing that we are instantiating S<int*>, ARGS will
12096 presently be {int*} -- but we need {int}. */
12099 }
12100 else
12101 {
12104 }
12106 /* If the template we're instantiating is incomplete, then clearly
12107 there's nothing we can do. */
12109 {
12110 /* We can try again later. */
12113 }
12115 /* If we've recursively instantiated too many templates, stop. */
12123 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
12128 else
12129 {
12132 }
12136 /* Use #pragma pack from the template context. */
12142 /* Set the input location to the most specialized template definition.
12143 This is needed if tsubsting causes an error. */
12157 {
12160 /* Adjust visibility for template arguments. */
12162 }
12168 /* We should never instantiate a nested class before its enclosing
12169 class; we need to look up the nested class by name before we can
12170 instantiate it, and that lookup should instantiate the enclosing
12171 class. */
12176 /* Defer access checking while we substitute into the types named in
12177 the base-clause. */
12180 {
12181 tree pbase_binfo;
12184 /* Substitute into each of the bases to determine the actual
12185 basetypes. */
12187 {
12188 tree base;
12194 {
12195 expanded_bases =
12202 }
12205 {
12207 /* Extract the already-expanded base class. */
12209 else
12210 /* Substitute to figure out the base class. */
12212 NULL_TREE);
12220 }
12221 }
12223 /* The list is now in reverse order; correct that. */
12225 }
12226 /* Now call xref_basetypes to set up all the base-class
12227 information. */
12235 /* Now that our base classes are set up, enter the scope of the
12236 class, so that name lookups into base classes, etc. will work
12237 correctly. This is precisely analogous to what we do in
12238 begin_class_definition when defining an ordinary non-template
12239 class, except we also need to push the enclosing classes. */
12242 /* Now check accessibility of the types named in its base-clause,
12243 relative to the scope of the class. */
12246 /* A vector to hold members marked with attribute used. */
12249 /* Now members are processed in the order of declaration. */
12252 {
12256 {
12258 {
12260 /* A closure type for a lambda in an NSDMI or default argument.
12261 Ignore it; it will be regenerated when needed. */
12264 /* If the member is a class template, we've
12265 already substituted its type. */
12275 {
12278 /* Now, install the tag. We don't use pushtag
12279 because that does too much work -- creating an
12280 implicit typedef, which we've already done. */
12285 }
12286 }
12288 {
12289 tree r;
12299 /* Instantiate members marked with attribute used. */
12305 }
12308 /* A closure type for a lambda in an NSDMI or default argument.
12310 else
12311 {
12312 /* Build new TYPE_FIELDS. */
12316 {
12317 tree r;
12322 /* The file and line for this declaration, to
12323 assist in error message reporting. Since we
12324 called push_tinst_level above, we don't need to
12325 restore these. */
12335 {
12336 /* A capture pack became multiple fields. */
12339 }
12342 {
12346 {
12347 /* In [temp.inst]:
12349 [t]he initialization (and any associated
12350 side-effects) of a static data member does
12351 not occur unless the static data member is
12352 itself used in a way that requires the
12353 definition of the static data member to
12354 exist.
12356 Therefore, we do not substitute into the
12357 initialized for the static data member here. */
12358 finish_static_data_member_decl
12364 /* Instantiate members marked with attribute used. */
12367 }
12369 {
12370 /* Determine whether R has a valid type and can be
12371 completed later. If R is invalid, then its type
12372 is replaced by error_mark_node. */
12378 {
12379 /* If R's type couldn't be completed and
12380 it isn't a flexible array member (whose
12381 type is incomplete by definition) give
12382 an error. */
12385 }
12390 {
12393 }
12397 }
12399 /* If it is a TYPE_DECL for a class-scoped
12400 ENUMERAL_TYPE, such a thing will already have
12401 been added to the field list by tsubst_enum
12402 in finish_member_declaration case above. */
12406 {
12409 }
12410 }
12411 }
12412 }
12413 }
12414 else
12415 {
12418 {
12419 /* Build new CLASSTYPE_FRIEND_CLASSES. */
12423 {
12424 /* template <class T> friend class C; */
12426 }
12428 {
12429 /* template <class T> friend class C::D; */
12434 }
12437 {
12438 /* This could be either
12440 friend class T::C;
12442 when dependent_type_p is false or
12444 template <class U> friend class T::C;
12446 otherwise. */
12447 /* Bump processing_template_decl in case this is something like
12448 template <class T> friend struct A<T>::B. */
12453 }
12455 /* friend class C<T>; */
12459 /* Otherwise it's
12461 friend class C;
12463 where C is already declared or
12465 friend class C<int>;
12467 We don't have to do anything in these cases. */
12471 }
12472 else
12473 {
12474 /* Build new DECL_FRIENDLIST. */
12475 tree r;
12477 /* The file and line for this declaration, to
12478 assist in error message reporting. Since we
12479 called push_tinst_level above, we don't need to
12480 restore these. */
12484 {
12487 }
12492 {
12495 }
12496 }
12497 }
12498 }
12501 {
12502 /* Restore these before substituting into the lambda capture
12503 initializers. */
12506 }
12508 /* Set the file and line number information to whatever is given for
12509 the class itself. This puts error messages involving generated
12510 implicit functions at a predictable point, and the same point
12511 that would be used for non-template classes. */
12518 /* Remember if instantiating this class ran into errors, so we can avoid
12519 instantiating member functions in limit_bad_template_recursion. We set
12520 this flag even if the problem was in another instantiation triggered by
12521 this one, as that will likely also cause trouble for member functions. */
12525 /* We don't instantiate default arguments for member functions. 14.7.1:
12527 The implicit instantiation of a class template specialization causes
12528 the implicit instantiation of the declarations, but not of the
12529 definitions or default arguments, of the class member functions,
12530 member classes, static data members and member templates.... */
12535 /* Now that we've gone through all the members, instantiate those
12536 marked with attribute used. We must do this in the context of
12537 the class -- not the context we pushed from, as that might be
12538 inside a template and change the behaviour of mark_used. */
12548 /* The vtable for a template class can be emitted in any translation
12549 unit in which the class is instantiated. When there is no key
12550 method, however, finish_struct_1 will already have added TYPE to
12551 the keyed_classes. */
12556 }
12558 tree
12560 {
12561 tree r;
12567 else
12568 {
12574 }
12577 }
12579 /* Given a function parameter pack TMPL_PARM and some function parameters
12580 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
12581 and set *SPEC_P to point at the next point in the list. */
12583 tree
12585 {
12586 /* Collect all of the extra "packed" parameters into an
12587 argument pack. */
12588 tree argpack;
12599 {
12600 /* The instantiation is still a parameter pack; don't wrap it in a
12601 NONTYPE_ARGUMENT_PACK. */
12604 }
12605 else
12606 {
12607 /* Fill in PARMVEC with all of the parameters. */
12611 {
12617 }
12619 /* Build the argument packs. */
12621 }
12625 }
12627 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
12628 NONTYPE_ARGUMENT_PACK. */
12630 static tree
12632 {
12634 }
12636 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
12637 pack expansion with no extra args, 2 if it has extra args, or 0
12638 if it is not a pack expansion. */
12640 static int
12642 {
12644 /* We're being called before this happens in tsubst_pack_expansion. */
12651 /* A decl pack is itself an expansion. */
12658 }
12661 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
12663 static tree
12665 {
12672 }
12674 /* This is a subroutine of tsubst_pack_expansion.
12676 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
12677 mechanism to store the (non complete list of) arguments of the
12678 substitution and return a non substituted pack expansion, in order
12679 to wait for when we have enough arguments to really perform the
12680 substitution. */
12682 static bool
12684 tree parm_packs,
12687 {
12692 /* If one pack has an expansion and another pack has a normal
12693 argument or if one pack has an empty argument and an another
12694 one hasn't then tsubst_pack_expansion cannot perform the
12695 substitution and need to fall back on the
12696 PACK_EXPANSION_EXTRA mechanism. */
12700 {
12701 /* If all the actual packs are pack expansions, we can still
12702 subsitute directly. */
12704 {
12714 }
12716 }
12719 {
12723 parm_pack;
12725 {
12730 /* We can't substitute a pack expansion with extra args into
12731 our pattern. */
12735 else
12737 }
12740 {
12743 }
12744 }
12746 }
12748 /* [temp.variadic]/6 says that:
12750 The instantiation of a pack expansion [...]
12751 produces a list E1,E2, ..., En, where N is the number of elements
12752 in the pack expansion parameters.
12754 This subroutine of tsubst_pack_expansion produces one of these Ei.
12756 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
12757 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
12758 PATTERN, and each TREE_VALUE is its corresponding argument pack.
12759 INDEX is the index 'i' of the element Ei to produce. ARGS,
12760 COMPLAIN, and IN_DECL are the same parameters as for the
12761 tsubst_pack_expansion function.
12763 The function returns the resulting Ei upon successful completion,
12764 or error_mark_node.
12766 Note that this function possibly modifies the ARGS parameter, so
12767 it's the responsibility of the caller to restore it. */
12769 static tree
12771 tree parm_packs,
12773 tree args /* This parm gets
12775 tsubst_flags_t complain,
12776 tree in_decl)
12777 {
12778 tree t;
12781 /* For each parameter pack, change the substitution of the parameter
12782 pack to the ith argument in its argument pack, then expand the
12783 pattern. */
12785 {
12790 ith_elem_is_expansion |=
12793 /* Select the Ith argument from the pack. */
12797 {
12799 {
12804 }
12805 else
12807 }
12808 else
12809 {
12814 {
12816 /* Update the corresponding argument. */
12818 }
12819 else
12820 /* Re-use the ARGUMENT_PACK_SELECT. */
12822 }
12824 }
12826 /* Substitute into the PATTERN with the (possibly altered)
12827 arguments. */
12829 /* Expanding a fixed parameter pack from
12830 coerce_template_parameter_pack. */
12836 else
12837 {
12840 /* When expanding the fake auto... pack expansion from add_capture, we
12841 need to mark that the expansion is no longer a pack. */
12843 }
12845 /* If the Ith argument pack element is a pack expansion, then
12846 the Ith element resulting from the substituting is going to
12847 be a pack expansion as well. */
12852 }
12854 /* When the unexpanded parameter pack in a fold expression expands to an empty
12855 sequence, the value of the expression is as follows; the program is
12856 ill-formed if the operator is not listed in this table.
12858 && true
12859 || false
12860 , void() */
12862 tree
12864 {
12868 {
12877 }
12883 }
12885 /* Given a fold-expression T and a current LEFT and RIGHT operand,
12886 form an expression that combines the two terms using the
12887 operator of T. */
12889 static tree
12891 {
12896 // Handle compound assignment operators.
12903 {
12912 complain);
12913 }
12914 }
12916 /* Substitute ARGS into the pack of a fold expression T. */
12920 {
12922 }
12924 /* Substitute ARGS into the pack of a fold expression T. */
12928 {
12930 }
12932 /* Expand a PACK of arguments into a grouped as left fold.
12933 Given a pack containing elements A0, A1, ..., An and an
12934 operator @, this builds the expression:
12936 ((A0 @ A1) @ A2) ... @ An
12938 Note that PACK must not be empty.
12940 The operator is defined by the original fold expression T. */
12942 static tree
12944 {
12947 {
12950 }
12952 }
12954 /* Substitute into a unary left fold expression. */
12956 static tree
12958 tree in_decl)
12959 {
12964 {
12968 }
12971 else
12973 }
12975 /* Substitute into a binary left fold expression.
12977 Do ths by building a single (non-empty) vector of argumnts and
12978 building the expression from those elements. */
12980 static tree
12982 tree in_decl)
12983 {
12992 {
12997 }
13005 }
13007 /* Expand a PACK of arguments into a grouped as right fold.
13008 Given a pack containing elementns A0, A1, ..., and an
13009 operator @, this builds the expression:
13011 A0@ ... (An-2 @ (An-1 @ An))
13013 Note that PACK must not be empty.
13015 The operator is defined by the original fold expression T. */
13017 tree
13019 {
13020 // Build the expression.
13024 {
13027 }
13029 }
13031 /* Substitute into a unary right fold expression. */
13033 static tree
13035 tree in_decl)
13036 {
13041 {
13045 }
13048 else
13050 }
13052 /* Substitute into a binary right fold expression.
13054 Do ths by building a single (non-empty) vector of arguments and
13055 building the expression from those elements. */
13057 static tree
13059 tree in_decl)
13060 {
13069 {
13074 }
13083 }
13085 /* Walk through the pattern of a pack expansion, adding everything in
13086 local_specializations to a list. */
13088 class el_data
13089 {
13091 /* Set of variables declared within the pattern. */
13093 /* Set of AST nodes that have been visited by the traversal. */
13095 /* List of local_specializations used within the pattern. */
13096 tree extra;
13097 tsubst_flags_t complain;
13098 /* True iff we don't want to walk into unevaluated contexts. */
13100 /* The unevaluated contexts that we avoided walking. */
13105 };
13106 static tree
13108 {
13115 {
13119 }
13122 /* Remember local typedefs (85214). */
13126 {
13132 {
13135 decl2
13141 {
13144 }
13145 }
13146 }
13148 {
13149 /* Since we defer implicit capture, look in the parms and body. */
13155 }
13157 {
13159 /* Don't mess with variables declared within the pattern. */
13162 {
13163 /* Maybe pull out the PARM_DECL for a partial instantiation. */
13166 {
13172 }
13174 {
13175 /* Handle lambda capture here, since we aren't doing any
13176 substitution now, and so tsubst_copy won't call
13177 process_outer_var_ref. */
13181 {
13187 {
13188 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
13189 proxies. */
13191 {
13196 }
13198 }
13199 }
13200 }
13201 }
13205 }
13207 }
13208 static tree
13210 {
13212 /* Walk the pattern twice, ignoring unevaluated operands the first time
13213 around, so that if a local specialization appears in both an evaluated
13214 and unevaluated context we prefer to process it in the evaluated context
13215 (since e.g. process_outer_var_ref is a no-op inside an unevaluated
13216 context). */
13219 /* Now walk the unevaluated contexts we skipped the first time around. */
13222 {
13225 }
13227 }
13229 /* Extract any uses of local_specializations from PATTERN and add them to ARGS
13230 for use in PACK_EXPANSION_EXTRA_ARGS. */
13232 tree
13234 {
13235 /* Make a copy of the extra arguments so that they won't get changed
13236 out from under us. */
13242 }
13244 /* Apply any local specializations from PACK_EXPANSION_EXTRA_ARGS and add the
13245 normal template args to ARGS. */
13247 tree
13249 {
13251 {
13253 {
13254 /* The partial instantiation involved local declarations collected in
13255 extract_local_specs; map from the general template to our local
13256 context. */
13262 /* else inst is already a full instantiation of the pack. */
13264 }
13267 }
13269 {
13270 /* This can happen after dependent substitution into a
13271 requires-expr or a lambda that uses constexpr if. */
13274 }
13275 else
13278 }
13280 /* Substitute ARGS into T, which is an pack expansion
13281 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
13282 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
13283 (if only a partial substitution could be performed) or
13284 ERROR_MARK_NODE if there was an error. */
13285 tree
13287 tree in_decl)
13288 {
13289 tree pattern;
13293 tree result;
13300 /* Add in any args remembered from an earlier partial instantiation. */
13305 /* Determine the argument packs that will instantiate the parameter
13306 packs used in the expansion expression. While we're at it,
13307 compute the number of arguments to be expanded and make sure it
13308 is consistent. */
13311 {
13318 {
13323 in_decl),
13324 complain);
13325 else
13328 complain);
13329 }
13331 {
13333 {
13336 parm_pack);
13338 }
13341 }
13343 {
13344 /* We know we have correct local_specializations if this
13345 expansion is at function scope, or if we're dealing with a
13346 local parameter in a requires expression; for the latter,
13347 tsubst_requires_expr set it up appropriately. */
13350 else
13351 /* We can't rely on local_specializations for a parameter
13352 name used later in a function declaration (such as in a
13353 late-specified return type). Even if it exists, it might
13354 have the wrong value for a recursive call. */
13358 {
13359 /* This parameter pack was used in an unevaluated context. Just
13360 make a dummy decl, since it's only used for its type. */
13365 /* Partial instantiation of the parm_pack, we can't build
13366 up an argument pack yet. */
13368 else
13370 }
13372 /* This argument pack isn't fully instantiated yet. */
13374 }
13376 {
13380 }
13381 else
13382 {
13391 }
13398 /* This can only happen if we forget to expand an argument
13399 pack somewhere else. Just return an error, silently. */
13400 {
13404 }
13407 {
13411 /* Don't bother trying to do a partial substitution with
13412 incomplete packs; we'll try again after deduction. */
13419 {
13424 pattern);
13425 else
13427 pattern);
13429 }
13431 /* Keep track of the parameter packs and their corresponding
13432 argument packs. */
13435 }
13436 else
13437 {
13438 /* We can't substitute for this parameter pack. We use a flag as
13439 well as the missing_level counter because function parameter
13440 packs don't have a level. */
13443 }
13444 }
13446 /* If the expansion is just T..., return the matching argument pack, unless
13447 we need to call convert_from_reference on all the elements. This is an
13448 important optimization; see c++/68422. */
13451 {
13454 /* If the argument pack is a single pack expansion, pull it out. */
13459 /* Types need no adjustment, nor does sizeof..., and if we still have
13460 some pack expansion args we won't do anything yet. */
13465 /* Also optimize expression pack expansions if we can tell that the
13466 elements won't have reference type. */
13472 /* Otherwise use the normal path so we get convert_from_reference. */
13473 }
13475 /* We cannot expand this expansion expression, because we don't have
13476 all of the argument packs we need. */
13478 {
13479 /* We got some full packs, but we can't substitute them in until we
13480 have values for all the packs. So remember these until then. */
13486 }
13488 /* If NEED_LOCAL_SPECIALIZATIONS then we're in a late-specified return
13489 type, so create our own local specializations map; the current map is
13490 either NULL or (in the case of recursive unification) might have
13491 bindings that we don't want to use or alter. */
13496 {
13497 /* There were no real arguments, we're just replacing a parameter
13498 pack with another version of itself. Substitute into the
13499 pattern and return a PACK_EXPANSION_*. The caller will need to
13500 deal with that. */
13503 else
13509 {
13510 /* This is a fake auto... pack expansion created in add_capture with
13511 _PACKS that don't appear in the pattern. Copy one over. */
13518 }
13520 }
13524 /* For each argument in each argument pack, substitute into the
13525 pattern. */
13529 {
13531 i,
13533 in_decl);
13536 {
13539 }
13540 }
13542 /* Update ARGS to restore the substitution from parameter packs to
13543 their argument packs. */
13545 {
13552 else
13553 {
13561 /* Update the corresponding argument. */
13565 else
13567 }
13568 }
13570 /* If the dependent pack arguments were such that we end up with only a
13571 single pack expansion again, there's no need to keep it in a TREE_VEC. */
13577 }
13579 /* Make an argument pack out of the TREE_VEC VEC. */
13581 static tree
13583 {
13584 tree pack;
13588 else
13589 {
13592 }
13595 }
13597 /* Return an exact copy of template args T that can be modified
13598 independently. */
13600 static tree
13602 {
13610 {
13615 }
13621 }
13623 /* Substitute ARGS into the *_ARGUMENT_PACK orig_arg. */
13625 tree
13627 tree in_decl)
13628 {
13629 /* This flag is used only during deduction, and we don't expect to
13630 substitute such ARGUMENT_PACKs. */
13633 /* Substitute into each of the arguments. */
13642 /* If we're substituting into a generic ARGUMENT_PACK for a variadic
13643 template parameter, we might be able to avoid allocating a new
13644 ARGUMENT_PACK and reuse the corresponding ARGUMENT_PACK from ARGS
13645 if the substituted result is identical to it. */
13647 {
13654 {
13657 }
13658 }
13660 tree new_arg;
13662 {
13665 }
13666 else
13667 {
13670 }
13673 }
13675 /* Substitute ARGS into the vector or list of template arguments T. */
13677 tree
13679 {
13683 /* In "sizeof(X<I>)" we need to evaluate "I". */
13684 cp_evaluated ev;
13690 /* True iff the substituted result is identical to T. */
13694 {
13696 tree new_arg;
13703 {
13704 /* Substitute into an expansion expression. */
13708 /* Add to the expanded length adjustment the number of
13709 expanded arguments. We subtract one from this
13710 measurement, because the argument pack expression
13711 itself is already counted as 1 in
13712 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
13713 the argument pack is empty. */
13715 }
13718 else
13727 }
13734 /* If ARGS and T are both multi-level, the substituted result may be
13735 identical to ARGS. */
13740 /* If T appears to be a vector of generic template arguments, the
13741 substituted result may be identical to the corresponding level
13742 from ARGS. */
13744 {
13749 }
13751 /* If the substituted result is identical to MAYBE_REUSE, return
13752 it and avoid allocating a new TREE_VEC, as an optimization. */
13758 /* If T consists of only a pack expansion for which substitution yielded
13759 a TREE_VEC of the expanded elements, then reuse that TREE_VEC instead
13760 of effectively making a copy. */
13766 /* Make space for the expanded arguments coming from template
13767 argument packs. */
13769 /* T can contain TREE_VECs. That happens if T contains the
13770 arguments for a member template.
13771 In that case each TREE_VEC in T represents a level of template
13772 arguments, and T won't carry any non defaulted argument count.
13773 It will rather be the nested TREE_VECs that will carry one.
13774 In other words, T carries a non defaulted argument count only
13775 if it doesn't contain any nested TREE_VEC. */
13777 {
13781 }
13785 {
13790 {
13791 /* Now expand the template argument pack "in place". */
13794 }
13795 else
13796 {
13798 out++;
13799 }
13800 }
13804 }
13806 /* Substitute ARGS into one level PARMS of template parameters. */
13808 static tree
13810 {
13817 {
13825 }
13828 }
13830 /* Return the result of substituting ARGS into the template parameters
13831 given by PARMS. If there are m levels of ARGS and m + n levels of
13832 PARMS, then the result will contain n levels of PARMS. For
13833 example, if PARMS is `template <class T> template <class U>
13834 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
13835 result will be `template <int*, double, class V>'. */
13837 static tree
13839 {
13843 /* When substituting into a template, we must set
13844 PROCESSING_TEMPLATE_DECL as the template parameters may be
13845 dependent if they are based on one-another, and the dependency
13846 predicates are short-circuit outside of templates. */
13853 {
13862 }
13867 }
13869 /* Return the result of substituting ARGS into one template parameter
13870 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
13871 parameter and which TREE_PURPOSE is the default argument of the
13872 template parameter. */
13874 static tree
13876 {
13899 }
13901 /* Substitute in-place the TEMPLATE_PARM_CONSTRAINTS of each template
13902 parameter in PARMS for sake of declaration matching. */
13904 static void
13906 tsubst_flags_t complain)
13907 {
13910 {
13916 }
13918 }
13920 /* Substitute the ARGS into the indicated aggregate (or enumeration)
13921 type T. If T is not an aggregate or enumeration type, it is
13922 handled as if by tsubst. IN_DECL is as for tsubst. If
13923 ENTERING_SCOPE is nonzero, T is the context for a template which
13924 we are presently tsubst'ing. Return the substituted value. */
13926 static tree
13928 tree args,
13929 tsubst_flags_t complain,
13930 tree in_decl,
13932 {
13936 /* Handle typedefs via tsubst so that they get consistently reused. */
13938 {
13943 /* The effect of entering_scope is that for a dependent specialization
13944 A<T>, lookup_template_class prefers to return A's primary template
13945 type instead of the implicit instantiation. So when entering_scope,
13946 we mirror this behavior by inspecting TYPE_CANONICAL appropriately,
13947 taking advantage of the fact that lookup_template_class links the two
13948 types by setting TYPE_CANONICAL of the latter to the former. */
13956 }
13959 {
13967 }
13968 }
13970 /* The part of tsubst_aggr_type that's shared with the RECORD_, UNION_
13971 and ENUMERAL_TYPE cases of tsubst. */
13973 static tree
13975 tree args,
13976 tsubst_flags_t complain,
13977 tree in_decl,
13979 {
13981 {
13984 /* Figure out what arguments are appropriate for the
13985 type we are trying to find. For example, given:
13987 template <class T> struct S;
13988 template <class T, class U> void f(T, U) { S<U> su; }
13990 and supposing that we are instantiating f<int, double>,
13991 then our ARGS will be {int, double}, but, when looking up
13992 S we only want {double}. */
14001 }
14002 else
14003 /* This is not a template type, so there's nothing to do. */
14005 }
14007 /* Map from a FUNCTION_DECL to a vec of default argument instantiations,
14008 indexed in reverse order of the parameters. */
14012 /* Return a reference to the vec* of defarg insts for FN. */
14016 {
14020 tree_vec_map **slot
14023 {
14026 }
14028 }
14030 /* Substitute into the default argument ARG (a default argument for
14031 FN), which has the indicated TYPE. */
14033 tree
14035 tsubst_flags_t complain)
14036 {
14039 /* This can happen in invalid code. */
14043 /* Shortcut {}. */
14058 /* Remember the location of the pointer to the vec rather than the location
14059 of the particular element, in case the vec grows in tsubst_expr. */
14061 /* Index in reverse order to avoid allocating space for initial parameters
14062 that don't have default arguments. */
14069 /* This default argument came from a template. Instantiate the
14070 default argument here, not in tsubst. In the case of
14071 something like:
14073 template <class T>
14074 struct S {
14075 static T t();
14076 void f(T = t());
14077 };
14079 we must be careful to do name lookup in the scope of S<T>,
14080 rather than in the current class. */
14084 /* So in_immediate_context knows this is a default argument. */
14088 /* The default argument expression may cause implicitly defined
14089 member functions to be synthesized, which will result in garbage
14090 collection. We must treat this situation as if we were within
14091 the body of function so as to avoid collecting live data on the
14092 stack. */
14099 /* Make sure the default argument is reasonable. */
14116 }
14118 /* Substitute into all the default arguments for FN. */
14120 static void
14122 {
14123 tree arg;
14124 tree tmpl_args;
14128 /* If this function is not yet instantiated, we certainly don't need
14129 its default arguments. */
14132 /* Don't do this again for clones. */
14138 arg;
14144 complain);
14145 }
14147 /* Hash table mapping a FUNCTION_DECL to its dependent explicit-specifier. */
14150 /* Store a pair to EXPLICIT_SPECIFIER_MAP. */
14152 void
14154 {
14159 }
14161 /* Lookup an element in EXPLICIT_SPECIFIER_MAP. */
14163 tree
14165 {
14167 }
14169 /* Given T, a FUNCTION_TYPE or METHOD_TYPE, construct and return a corresponding
14170 FUNCTION_TYPE or METHOD_TYPE whose return type is RETURN_TYPE, argument types
14171 are ARG_TYPES, and exception specification is RAISES, and otherwise is
14172 identical to T. */
14174 static tree
14177 {
14180 tree new_type;
14182 {
14185 }
14186 else
14187 {
14189 /* Don't pick up extra function qualifiers from the basetype. */
14192 {
14193 /* [temp.deduct]
14195 Type deduction may fail for any of the following
14196 reasons:
14198 -- Attempting to create "pointer to member of T" when T
14199 is not a class type. */
14202 r);
14204 }
14208 }
14214 }
14216 /* Check if the function type of DECL, a FUNCTION_DECL, agrees with the type of
14217 each of its formal parameters. If there is a disagreement then rebuild
14218 DECL's function type according to its formal parameter types, as part of a
14219 resolution for Core issues 1001/1322. */
14221 static void
14223 {
14226 {
14229 {
14233 {
14236 }
14240 }
14241 }
14252 {
14257 }
14259 {
14269 }
14277 }
14279 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
14281 static tree
14283 tree lambda_fntype)
14284 {
14289 /* Nobody should be tsubst'ing into non-template functions. */
14294 {
14297 }
14299 {
14300 /* If T is not dependent, just return it. */
14305 /* A non-templated friend doesn't get DECL_TEMPLATE_INFO. */
14309 /* Calculate the most general template of which R is a
14310 specialization. */
14313 /* We're substituting a lambda function under tsubst_lambda_expr but not
14314 directly from it; find the matching function we're already inside.
14315 But don't do this if T is a generic lambda with a single level of
14316 template parms, as in that case we're doing a normal instantiation. */
14322 /* Calculate the complete set of arguments used to
14323 specialize R. */
14325 (DECL_TEMPLATE_RESULT
14331 /* Check to see if we already have this specialization. */
14333 {
14336 /* The spec for these args might be a partial instantiation of the
14337 template, but here what we want is the FUNCTION_DECL. */
14339 }
14340 }
14341 else
14342 {
14343 /* This special case arises when we have something like this:
14345 template <class T> struct S {
14346 friend void f<int>(int, double);
14347 };
14349 Here, the DECL_TI_TEMPLATE for the friend declaration
14350 will be an IDENTIFIER_NODE. We are being called from
14351 tsubst_friend_function, and we want only to create a
14352 new decl (R) with appropriate types so that we can call
14353 determine_specialization. */
14354 friend_case:
14357 }
14364 /* If this is a static lambda, remove the 'this' pointer added in
14365 tsubst_lambda_expr now that we know the closure type. */
14379 /* If we hit excessive deduction depth, the type is bogus even if
14380 it isn't error_mark_node, so don't build a decl. */
14384 /* We do NOT check for matching decls pushed separately at this
14385 point, as they may not represent instantiations of this
14386 template, and in any case are considered separate under the
14387 discrete model. */
14391 /* Clear out the mangled name and RTL for the instantiation. */
14394 /* Leave DECL_INITIAL set on deleted instantiations. */
14400 /* Handle explicit(dependent-expr). */
14402 {
14410 else
14411 {
14414 }
14415 }
14417 /* OpenMP UDRs have the only argument a reference to the declared
14418 type. We want to diagnose if the declared type is a reference,
14419 which is invalid, but as references to references are usually
14420 quietly merged, diagnose it here. */
14422 {
14423 tree argtype
14428 "reference type %qT in "
14432 argtype);
14433 }
14436 /* Type-conversion operator. Reconstruct the name, in
14437 case it's the name of one of the template's parameters. */
14447 {
14452 }
14461 /* If this is an instantiation of a function with internal
14462 linkage, we already know what object file linkage will be
14463 assigned to the instantiation. */
14472 /* We'll re-clone as appropriate in instantiate_template. */
14475 /* If we aren't complaining now, return on error before we register
14476 the specialization so that we'll complain eventually. */
14482 /* Associate the constraints directly with the instantiation. We
14483 don't substitute through the constraints; that's only done when
14484 they are checked. */
14497 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
14498 this in the special friend case mentioned above where
14499 GEN_TMPL is NULL. */
14501 {
14506 tree new_r
14509 /* We instantiated this while substituting into
14510 the type earlier (template/friend54.C). */
14513 /* We're not supposed to instantiate default arguments
14514 until they are called, for a template. But, for a
14515 declaration like:
14517 template <class T> void f ()
14518 { extern void g(int i = T()); }
14520 we should do the substitution when the template is
14521 instantiated. We handle the member function case in
14522 instantiate_class_template since the default arguments
14523 might refer to other members of the class. */
14528 }
14530 {
14533 }
14534 else
14537 /* Copy the list of befriending classes. */
14541 {
14545 }
14548 {
14552 /* If this is an instantiation of a member template, clone it.
14553 If it isn't, that'll be handled by
14554 clone_constructors_and_destructors. */
14557 }
14563 /* Possibly limit visibility based on template args. */
14566 {
14570 }
14582 }
14584 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
14586 static tree
14589 {
14590 /* We can get here when processing a member function template,
14591 member class template, or template template parameter. */
14594 tree spec;
14595 tree tmpl_args;
14596 tree full_args;
14597 tree r;
14601 {
14602 /* Template template parameter is treated here. */
14606 /* If we get a real template back, return it. This can happen in
14607 the context of most_specialized_partial_spec. */
14610 else
14611 /* The new TEMPLATE_DECL was built in
14612 reduce_template_parm_level. */
14615 }
14618 {
14619 /* We might already have an instance of this template.
14620 The ARGS are for the surrounding class type, so the
14621 full args contain the tsubst'd args for the context,
14622 plus the innermost args from the template decl. */
14626 /* Because this is a template, the arguments will still be
14627 dependent, even after substitution. If
14628 PROCESSING_TEMPLATE_DECL is not set, the dependency
14629 predicates will short-circuit. */
14637 /* If this is a default template template argument,
14638 tsubst might not have changed anything. */
14645 {
14647 /* Type partial instantiations are stored as the type by
14648 lookup_template_class_1, not here as the template. */
14651 }
14652 }
14654 /* Make a new template decl. It will be similar to the
14655 original, but will record the current template arguments.
14656 We also create a new function declaration, which is just
14657 like the old one, but points to this new template, rather
14658 than the old one. */
14663 // Build new template info linking to the original template decl.
14665 {
14668 }
14669 else
14672 /* The template parameters for this new template are all the
14673 template parameters for the old template, except the
14674 outermost level of parameters. */
14677 = current_template_parms
14678 = (lambda_tparms
14679 ? lambda_tparms
14681 complain));
14688 else
14689 {
14691 {
14694 }
14698 else
14700 }
14706 {
14707 /* For a partial specialization, we need to keep pointing to
14708 the primary template. */
14710 {
14713 }
14717 }
14719 {
14722 }
14723 else
14724 {
14727 }
14734 {
14735 /* Propagate module information from the decl. */
14738 /* If this is a constrained template, the above tsubst of
14739 inner can find the unconstrained template, which may have
14740 come from an import. This is ok, because we don't
14741 register this instantiation (see below). */
14743 || (TEMPLATE_PARMS_CONSTRAINTS
14745 }
14754 /* Record this non-type partial instantiation. */
14760 }
14762 /* True if FN is the op() for a lambda in an uninstantiated template. */
14764 bool
14766 {
14771 }
14773 /* True if FN is the substitution (via tsubst_lambda_expr) of a function for
14774 which the above is true. */
14776 bool
14778 {
14784 }
14786 /* Return the LAMBDA_EXPR from which T was ultimately regenerated.
14787 If T is not a regenerated LAMBDA_EXPR, return T. */
14789 tree
14791 {
14795 }
14797 /* Return the set of template arguments used to regenerate the lambda T
14798 from its most general lambda. */
14800 tree
14802 {
14808 else
14810 }
14812 /* We're instantiating a variable from template function TCTX. Return the
14813 corresponding current enclosing scope. We can match them up using
14814 DECL_SOURCE_LOCATION because lambdas only ever have one source location, and
14815 the DECL_SOURCE_LOCATION for a function instantiation is updated to match
14816 the template definition in regenerate_decl_from_template. */
14818 static tree
14820 {
14823 /* We shouldn't ever need to do this for other artificial functions. */
14830 }
14832 /* Substitute the ARGS into the T, which is a _DECL. Return the
14833 result of the substitution. Issue error and warning messages under
14834 control of COMPLAIN. */
14836 static tree
14838 {
14839 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
14840 location_t saved_loc;
14845 /* Set the filename and linenumber to improve error-reporting. */
14850 {
14862 {
14870 {
14871 /* If there is a local specialization that isn't a
14872 parameter pack, it means that we're doing a "simple"
14873 substitution from inside tsubst_pack_expansion. Just
14874 return the local specialization (which will be a single
14875 parm). */
14882 /* Expand the TYPE_PACK_EXPANSION that provides the types for
14883 the parameters in this function parameter pack. */
14887 {
14890 /* Zero-length parameter packs are boring. Just substitute
14891 into the chain. */
14895 }
14896 else
14897 {
14898 /* All we did was update the type. Make a note of that. */
14901 }
14902 }
14904 /* Loop through all of the parameters we'll build. When T is
14905 a function parameter pack, LEN is the number of expanded
14906 types in EXPANDED_TYPES; otherwise, LEN is 1. */
14909 {
14916 /* We're on the Ith parameter of the function parameter
14917 pack. */
14918 {
14919 /* Get the Ith type. */
14922 /* Rename the parameter to include the index. */
14925 }
14927 /* We're dealing with a normal parameter. */
14935 {
14938 else
14941 }
14952 /* Keep track of the first new parameter we
14953 generate. That's what will be returned to the
14954 caller. */
14958 /* Build a proper chain of parameters when substituting
14959 into a function parameter pack. */
14962 }
14964 /* If cp_unevaluated_operand is set, we're just looking for a
14965 single dummy parameter, so don't keep going. */
14970 /* FIRST_R contains the start of the chain we've built. */
14972 }
14976 {
14983 {
14984 /* This field is a lambda capture pack. Return a TREE_VEC of
14985 the expanded fields to instantiate_class_template_1. */
14989 {
14992 }
14993 else
14994 {
14995 /* All we did was update the type. Make a note of that. */
14998 }
14999 }
15002 {
15005 {
15009 }
15019 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
15020 number of bits. */
15025 {
15026 /* Set up DECL_TEMPLATE_INFO so that we can get at the
15027 NSDMI in perform_member_init. Still set DECL_INITIAL
15028 so that we know there is one. */
15033 }
15034 /* We don't have to set DECL_CONTEXT here; it is set by
15035 finish_member_declaration. */
15044 }
15048 }
15052 /* We reach here only for member using decls. We also need to check
15053 uses_template_parms because DECL_DEPENDENT_P is not set for a
15054 using-declaration that designates a member of the current
15055 instantiation (c++/53549). */
15058 {
15059 /* True iff this using-decl was written as a pack expansion
15060 (and a pack appeared in its scope or name). If a pack
15061 appeared in both, we expand the packs separately and
15062 manually merge them. */
15067 {
15070 in_decl);
15072 }
15073 else
15079 {
15083 {
15086 }
15090 }
15091 else
15099 {
15101 {
15106 }
15108 }
15116 {
15125 {
15128 }
15132 }
15136 }
15137 else
15138 {
15141 }
15146 {
15157 {
15158 /* If this is the canonical decl, we don't have to
15159 mess with instantiations, and often we can't (for
15160 typename, template type parms and such). Note that
15161 TYPE_NAME is not correct for the above test if
15162 we've copied the type for a typedef. */
15168 }
15170 /* Check to see if we already have the specialization we
15171 need. */
15177 {
15180 {
15182 complain,
15185 /* The context and type of an injected-class-name are
15186 the same, so we don't need to substitute both. */
15188 /* If CTX is unchanged, then T is in fact the
15189 specialization we want. That situation occurs when
15190 referencing a static data member within in its own
15191 class. We can use pointer equality, rather than
15192 same_type_p, because DECL_CONTEXT is always
15193 canonical... */
15195 /* ... unless T is a member template; in which
15196 case our caller can be willing to create a
15197 specialization of that template represented
15198 by T. */
15202 }
15205 {
15212 /* We're fully specializing a template declaration, so
15213 we need to coerce the innermost arguments corresponding to
15214 the template. */
15215 argvec = (coerce_template_parms
15222 }
15223 }
15224 else
15225 {
15227 /* Subsequent calls to pushdecl will fill this in. */
15229 /* A local variable. */
15231 /* Unless this is a reference to a static variable from an
15232 enclosing function, in which case we need to fill it in now. */
15234 {
15238 }
15240 }
15241 /* If we already have the specialization we need, there is
15242 nothing more to do. */
15244 {
15247 }
15249 /* Create a new node for the specialization we need. */
15251 {
15254 else
15264 /* Substituting the type might have recursively instantiated this
15265 same alias (c++/86171). */
15268 {
15271 }
15272 }
15275 {
15281 {
15282 /* It may seem that this case cannot occur, since:
15284 typedef void f();
15285 void g() { f x; }
15287 declares a function, not a variable. However:
15289 typedef void f();
15290 template <typename T> void g() { T t; }
15291 template void g<f>();
15293 is an attempt to declare a variable with function
15294 type. */
15296 /* R is not yet sufficiently initialized, so we
15297 just use its name. */
15300 }
15302 /* Wait until cp_finish_decl to set this again, to handle
15303 circular dependency (template/instantiate6.C). */
15308 {
15310 /* If the DECL_VALUE_EXPR is converted to the declared type,
15311 preserve the identity so that gimplify_type_sizes works. */
15317 {
15320 }
15329 else
15333 }
15337 }
15343 /* Clear out the mangled name and RTL for the instantiation. */
15349 /* The initializer must not be expanded until it is required;
15350 see [temp.inst]. */
15354 {
15360 /* Possibly limit visibility based on template args. */
15363 {
15367 }
15369 }
15372 {
15373 /* A static data member declaration is always marked
15374 external when it is declared in-class, even if an
15375 initializer is present. We mimic the non-template
15376 processing here. */
15385 }
15386 else
15387 {
15392 }
15401 /* Preserve a typedef that names a type. */
15403 {
15407 /* common_handle_aligned_attribute doesn't apply the alignment
15408 to DECL_ORIGINAL_TYPE. */
15412 }
15415 }
15420 }
15421 #undef RETURN
15423 out:
15424 /* Restore the file and line information. */
15428 }
15430 /* Substitute into the complete parameter type list PARMS. */
15432 tree
15434 tree args,
15435 tsubst_flags_t complain,
15436 tree in_decl)
15437 {
15439 }
15441 /* Substitute into the ARG_TYPES of a function type.
15442 If END is a TREE_CHAIN, leave it and any following types
15443 un-substituted. */
15445 static tree
15447 tree args,
15448 tree end,
15449 tsubst_flags_t complain,
15450 tree in_decl)
15451 {
15460 {
15461 /* For a pack expansion, perform substitution on the
15462 entire expression. Later on, we'll handle the arguments
15463 one-by-one. */
15468 /* So that we'll spin through the parameters, one by one. */
15470 else
15471 {
15472 /* We only partially substituted into the parameter
15473 pack. Our type is TYPE_PACK_EXPANSION. */
15476 }
15477 }
15478 else
15481 /* Check if a substituted type is erroneous before substituting into
15482 the rest of the chain. */
15484 {
15491 {
15493 {
15497 }
15499 }
15500 }
15502 /* We do not substitute into default arguments here. The standard
15503 mandates that they be instantiated only when needed, which is
15504 done in build_over_call. */
15507 /* Except that we do substitute default arguments under tsubst_lambda_expr,
15508 since the new op() won't have any associated template arguments for us
15509 to refer to later. */
15521 {
15525 /* Do array-to-pointer, function-to-pointer conversion, and ignore
15526 top-level qualifiers as required. */
15530 {
15531 /* We've instantiated a template before its default arguments
15532 have been parsed. This can happen for a nested template
15533 class, and is not an error unless we require the default
15534 argument in a call of this function. */
15535 remaining_arg_types
15538 remaining_arg_types);
15539 }
15540 else
15541 remaining_arg_types
15543 }
15546 }
15548 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
15549 *not* handle the exception-specification for FNTYPE, because the
15550 initial substitution of explicitly provided template parameters
15551 during argument deduction forbids substitution into the
15552 exception-specification:
15554 [temp.deduct]
15556 All references in the function type of the function template to the
15557 corresponding template parameters are replaced by the specified tem-
15558 plate argument values. If a substitution in a template parameter or
15559 in the function type of the function template results in an invalid
15560 type, type deduction fails. [Note: The equivalent substitution in
15561 exception specifications is done only when the function is instanti-
15562 ated, at which point a program is ill-formed if the substitution
15563 results in an invalid type.] */
15565 static tree
15567 tree args,
15568 tsubst_flags_t complain,
15569 tree in_decl)
15570 {
15571 tree return_type;
15574 /* The TYPE_CONTEXT is not used for function/method types. */
15577 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
15578 failure. */
15582 {
15583 /* Substitute the argument types. */
15595 {
15596 /* DR 1207: 'this' is in scope in the trailing return type. */
15598 }
15600 /* Substitute the return type. */
15604 {
15607 }
15608 }
15609 else
15610 /* Substitute the return type. */
15615 /* DR 486 clarifies that creation of a function type with an
15616 invalid return type is a deduction failure. */
15619 {
15621 {
15624 else
15626 }
15628 }
15631 {
15632 /* Substitute the argument types. */
15637 }
15639 /* Construct a new type node and return it. */
15642 }
15644 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
15645 ARGS into that specification, and return the substituted
15646 specification. If there is no specification, return NULL_TREE. */
15648 static tree
15650 tree args,
15651 tsubst_flags_t complain,
15652 tree in_decl,
15654 {
15655 tree specs;
15656 tree new_specs;
15661 {
15662 /* A noexcept-specifier. */
15667 {
15668 /* Defer instantiation of noexcept-specifiers to avoid
15669 excessive instantiations (c++/49107). */
15672 {
15673 /* We already partially instantiated this member template,
15674 so combine the new args with the old. */
15679 }
15680 else
15681 {
15684 }
15685 }
15686 else
15687 {
15689 {
15691 args);
15693 }
15695 }
15697 /* We've instantiated a template before a noexcept-specifier
15698 contained therein has been parsed. This can happen for
15699 a nested template class:
15701 struct S {
15702 template<typename> struct B { B() noexcept(...); };
15703 struct A : B<int> { ... use B() ... };
15704 };
15706 where completing B<int> will trigger instantiating the
15707 noexcept, even though we only parse it at the end of S. */
15709 {
15712 }
15713 }
15715 {
15718 else
15720 {
15721 tree spec;
15726 {
15727 /* Expand the pack expansion type. */
15730 in_decl);
15736 else
15737 {
15738 /* We're substituting into a member template, so
15739 we got a TYPE_PACK_EXPANSION back. Add that
15740 expansion and move on. */
15744 expanded_specs,
15745 complain);
15748 }
15749 }
15752 {
15755 else
15760 complain);
15761 }
15764 }
15765 }
15767 }
15769 /* Substitute through a TREE_LIST of types or expressions, handling pack
15770 expansions. */
15772 tree
15774 {
15781 ;
15783 {
15787 }
15790 else
15798 ;
15800 {
15804 }
15807 else
15814 ;
15819 else
15830 /* Determine the number of arguments. */
15832 {
15835 }
15838 else
15842 {
15850 else
15852 }
15855 }
15857 /* Take the tree structure T and replace template parameters used
15858 therein with the argument vector ARGS. IN_DECL is an associated
15859 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
15860 Issue error and warning messages under control of COMPLAIN. Note
15861 that we must be relatively non-tolerant of extensions here, in
15862 order to preserve conformance; if we allow substitutions that
15863 should not be allowed, we may allow argument deductions that should
15864 not succeed, and therefore report ambiguous overload situations
15865 where there are none. In theory, we could allow the substitution,
15866 but indicate that it should have failed, and allow our caller to
15867 make sure that the right thing happens, but we don't try to do this
15868 yet.
15870 This function is used for dealing with types, decls and the like;
15871 for expressions, use tsubst_expr or tsubst_copy. */
15873 tree
15875 {
15910 /* Reuse typedefs. We need to do this to handle dependent attributes,
15911 such as attribute aligned. */
15914 {
15918 {
15919 /* DECL represents an alias template and we want to
15920 instantiate it. */
15924 }
15928 {
15932 }
15937 else
15938 /* The typedef is from a non-template context. */
15942 {
15944 r = cp_build_qualified_type
15948 }
15949 else
15950 {
15951 /* We don't have an instantiation yet, so drop the typedef. */
15956 }
15957 }
15974 {
15978 /* Fall through. */
16004 {
16009 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
16010 needed. */
16016 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
16017 with TREE_SIDE_EFFECTS that indicates this is not an integral
16018 constant expression. */
16021 {
16024 }
16027 }
16031 {
16039 else
16041 }
16042 /* Fall through. */
16046 {
16060 {
16063 /* See through ARGUMENT_PACK_SELECT arguments. */
16066 }
16071 {
16073 /* If ARG is an argument pack, we don't actually want to
16074 perform a substitution here, because substitutions
16075 for argument packs are only done
16076 element-by-element. We can get to this point when
16077 substituting the type of a non-type template
16078 parameter pack, when that type actually contains
16079 template parameter packs from an outer template, e.g.,
16081 template<typename... Types> struct A {
16082 template<Types... Values> struct B { };
16083 }; */
16087 {
16090 /* When building concept checks for the purpose of
16091 deducing placeholders, we can end up with wildcards
16092 where types are expected. Adjust this to the deduced
16093 value. */
16101 return cp_build_qualified_type
16103 }
16105 {
16106 /* We are processing a type constructed from a
16107 template template parameter. */
16118 /* Consider this code:
16120 template <template <class> class Template>
16121 struct Internal {
16122 template <class Arg> using Bind = Template<Arg>;
16123 };
16125 template <template <class> class Template, class Arg>
16126 using Instantiate = Template<Arg>; //#0
16128 template <template <class> class Template,
16129 class Argument>
16130 using Bind =
16131 Instantiate<Internal<Template>::template Bind,
16132 Argument>; //#1
16134 When #1 is parsed, the
16135 BOUND_TEMPLATE_TEMPLATE_PARM representing the
16136 parameter `Template' in #0 matches the
16137 UNBOUND_CLASS_TEMPLATE representing the argument
16138 `Internal<Template>::template Bind'; We then want
16139 to assemble the type `Bind<Argument>' that can't
16140 be fully created right now, because
16141 `Internal<Template>' not being complete, the Bind
16142 template cannot be looked up in that context. So
16143 we need to "store" `Bind<Argument>' for later
16144 when the context of Bind becomes complete. Let's
16145 store that in a TYPENAME_TYPE. */
16149 argvec),
16150 typename_type,
16151 complain);
16153 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
16154 are resolving nested-types in the signature of a
16155 member function templates. Otherwise ARG is a
16156 TEMPLATE_DECL and is the real template to be
16157 instantiated. */
16165 complain);
16166 return cp_build_qualified_type
16168 }
16171 else
16172 /* TEMPLATE_PARM_INDEX. */
16174 }
16177 /* This can happen during the attempted tsubst'ing in
16178 unify. This means that we don't yet have any information
16179 about the template parameter in question. */
16182 /* Early in template argument deduction substitution, we don't
16183 want to reduce the level of 'auto', or it will be confused
16184 with a normal template parm in subsequent deduction.
16185 Similarly, don't reduce the level of template parameters to
16186 avoid mismatches when deducing their types. */
16190 /* If we get here, we must have been looking at a parm for a
16191 more deeply nested template. Make a new version of this
16192 template parameter, but with a lower level. */
16195 {
16200 {
16203 }
16210 /* Cache the simple case of lowering a type parameter. */
16212 else
16213 {
16225 /* Propagate constraints on placeholders since they are
16226 only instantiated during satisfaction. */
16231 else
16233 }
16241 {
16243 /* We might need to substitute into the types of non-type
16244 template parameters. This also lowers the level of
16245 the ttp appropriately. */
16258 }
16261 /* OK, now substitute the type of the non-type parameter. We
16262 couldn't do it earlier because it might be an auto parameter,
16263 and we wouldn't need to if we had an argument. */
16272 }
16275 }
16281 /* We should never be tsubsting a binfo. */
16285 /* A vector of template arguments. */
16291 {
16295 /* [temp.deduct]
16297 Type deduction may fail for any of the following
16298 reasons:
16300 -- Attempting to create a pointer to reference type.
16301 -- Attempting to create a reference to a reference type or
16302 a reference to void.
16304 Core issue 106 says that creating a reference to a reference
16305 during instantiation is no longer a cause for failure. We
16306 only enforce this check in strict C++98 mode. */
16310 {
16313 /* We keep track of the last time we issued this error
16314 message to avoid spewing a ton of messages during a
16315 single bad template instantiation. */
16318 {
16323 else
16326 }
16329 }
16333 {
16335 {
16338 type);
16339 else
16341 type);
16342 }
16344 }
16346 {
16350 }
16352 /* In C++0x, during template argument substitution, when there is an
16353 attempt to create a reference to a reference type, reference
16354 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
16356 "If a template-argument for a template-parameter T names a type
16357 that is a reference to a type A, an attempt to create the type
16358 'lvalue reference to cv T' creates the type 'lvalue reference to
16359 A,' while an attempt to create the type type rvalue reference to
16360 cv T' creates the type T"
16361 */
16362 r = cp_build_reference_type
16365 else
16370 /* Will this ever be needed for TYPE_..._TO values? */
16374 }
16376 {
16379 {
16380 /* [temp.deduct]
16382 Type deduction may fail for any of the following
16383 reasons:
16385 -- Attempting to create "pointer to member of T" when T
16386 is not a class type. */
16390 }
16392 {
16396 }
16398 {
16402 }
16405 {
16406 /* The type of the implicit object parameter gets its
16407 cv-qualifiers from the FUNCTION_TYPE. */
16408 tree memptr;
16409 tree method_type
16414 complain);
16415 }
16416 else
16419 complain);
16420 }
16423 {
16424 tree fntype;
16425 tree specs;
16430 /* Substitute the exception specification. */
16438 }
16440 {
16445 /* As an optimization, we avoid regenerating the array type if
16446 it will obviously be the same as T. */
16450 /* These checks should match the ones in create_array_type_for_decl.
16452 [temp.deduct]
16454 The deduction may fail for any of the following reasons:
16456 -- Attempting to create an array with an element type that
16457 is void, a function type, or a reference type, or [DR337]
16458 an abstract class type. */
16464 {
16468 }
16481 {
16484 }
16487 }
16490 {
16493 {
16496 in_decl);
16501 {
16506 }
16508 }
16509 else
16522 {
16526 }
16528 {
16529 /* Normally, make_typename_type does not require that the CTX
16530 have complete type in order to allow things like:
16532 template <class T> struct S { typename S<T>::X Y; };
16534 But, such constructs have already been resolved by this
16535 point, so here CTX really should have complete type, unless
16536 it's a partial instantiation. */
16539 }
16541 /* FIXME: TYPENAME_IS_CLASS_P conflates 'class' vs 'struct' vs 'union'
16542 tags. TYPENAME_TYPE should probably remember the exact tag that
16543 was written. */
16544 enum tag_types tag_type
16554 {
16557 }
16560 {
16562 {
16566 else
16568 }
16570 {
16574 else
16576 }
16577 }
16579 return cp_build_qualified_type
16581 }
16584 {
16596 }
16599 {
16600 tree type;
16614 complain);
16615 }
16618 {
16619 tree type;
16636 else
16637 {
16641 /* In a template ~id could be either a complement expression
16642 or an unqualified-id naming a destructor; if instantiating
16643 it produces an expression, it's not an id-expression or
16644 member access. */
16647 }
16652 }
16655 {
16659 else
16666 }
16685 /* We should use one of the expression tsubsts for these codes. */
16691 }
16692 }
16694 /* Convenience wrapper over tsubst for substituting into the LHS
16695 of the :: scope resolution operator. */
16697 static tree
16699 {
16702 }
16704 /* OLDFNS is a lookup set of member functions from some class template, and
16705 NEWFNS is a lookup set of member functions from NEWTYPE, a specialization
16706 of that class template. Return the subset of NEWFNS which are
16707 specializations of a function from OLDFNS. */
16709 static tree
16711 {
16712 /* Record all member functions from the old lookup set OLDFNS into
16713 VISIBLE_SET. */
16717 {
16719 {
16720 /* Imprecisely handle dependent using-decl by keeping all members
16721 in the new lookup set that are defined in a base class, i.e.
16722 members that could plausibly have been introduced by this
16723 dependent using-decl.
16724 FIXME: Track which members are introduced by a dependent
16725 using-decl precisely, perhaps by performing another lookup
16726 from the substituted USING_DECL_SCOPE. */
16729 }
16730 else
16732 }
16734 /* Returns true iff (a less specialized version of) FN appeared in
16735 the old lookup set OLDFNS. */
16738 /* FN is a member function from a base class, introduced via a
16739 using-decl; if it might have been introduced by a dependent
16740 using-decl then just conservatively keep it, otherwise look
16741 in the old lookup set for FN exactly. */
16744 /* FN is a member function template from the current class;
16745 look in the old lookup set for the TEMPLATE_DECL from which
16746 it was specialized. */
16748 else
16749 /* FN is a non-template member function from the current class;
16750 look in the old lookup set for the FUNCTION_DECL from which
16751 it was specialized. */
16754 };
16759 {
16762 }
16766 /* Filter out from NEWFNS the member functions that weren't
16767 previously visible according to OLDFNS. */
16772 {
16774 filtered_size++;
16775 }
16781 }
16783 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
16784 expression on the left-hand side of the "." or "->" operator. We
16785 only do the lookup if we had a dependent BASELINK. Otherwise we
16786 adjust it onto the instantiated heirarchy. */
16788 static tree
16791 {
16803 {
16810 }
16818 {
16823 /* See maybe_dependent_member_ref. */
16825 {
16828 template_args);
16831 }
16834 /* Treat as-if non-dependent below. */
16839 complain);
16841 {
16842 /* Filter out from the new lookup set those functions which didn't
16843 appear in the original lookup set (in a less specialized form).
16844 This is needed to preserve the consistency of member lookup
16845 performed in an incomplete-class context, within which
16846 later-declared members ought to remain invisible. */
16849 binfo_type);
16851 }
16854 {
16860 }
16863 }
16864 else
16865 {
16866 /* We're going to overwrite pieces below, make a duplicate. */
16870 {
16871 /* The decl we found was from non-dependent scope, but we still need
16872 to update the binfos for the instantiated qualifying_scope. */
16876 }
16877 }
16879 /* If lookup found a single function, mark it as used at this point.
16880 (If lookup found multiple functions the one selected later by
16881 overload resolution will be marked as used at that point.) */
16883 {
16889 /* We might have instantiated an auto function. */
16891 }
16894 {
16895 /* Add back the template arguments, if present. */
16900 /* Update the conversion operator type. */
16902 }
16908 {
16910 qualifying_scope,
16911 object_type);
16913 /* We need to call adjust_result_of_qualified_name_lookup in case the
16914 destructor names a base class, but we unset BASELINK_QUALIFIED_P
16915 so that we still get virtual function binding. */
16917 }
16920 }
16922 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
16923 true if the qualified-id will be a postfix-expression in-and-of
16924 itself; false if more of the postfix-expression follows the
16925 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
16926 of "&". */
16928 static tree
16932 {
16933 tree expr;
16934 tree scope;
16935 tree name;
16937 tree template_args;
16942 /* Figure out what name to look up. */
16945 {
16954 }
16955 else
16956 {
16959 }
16961 /* Substitute into the qualifying scope. When there are no ARGS, we
16962 are just trying to simplify a non-dependent expression. In that
16963 case the qualifying scope may be dependent, and, in any case,
16964 substituting will not help. */
16967 {
16970 }
16971 else
16975 {
16977 /* We built one in tsubst_baselink. */
16979 else
16980 {
16983 template_args);
16985 QUALIFIED_NAME_IS_TEMPLATE
16987 }
16990 }
16993 {
16995 {
16996 /* A BIT_NOT_EXPR is used to represent a destructor. */
16998 {
17002 }
17003 else
17006 }
17007 else
17011 {
17013 {
17017 }
17019 }
17020 }
17023 {
17027 /* Remember that there was a reference to this entity. */
17030 }
17033 {
17039 }
17042 {
17043 /* We may be repeating a check already done during parsing, but
17044 if it was well-formed and passed then, it will pass again
17045 now, and if it didn't, we wouldn't have got here. The case
17046 we want to catch is when we couldn't tell then, and can now,
17047 namely when templ prior to substitution was an
17048 identifier. */
17054 complain);
17055 else
17057 }
17063 {
17064 expr = (adjust_result_of_qualified_name_lookup
17066 expr = (finish_qualified_id_expr
17070 }
17072 /* Expressions do not generally have reference type. */
17074 /* However, if we're about to form a pointer-to-member, we just
17075 want the referenced member referenced. */
17085 }
17087 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
17088 initializer, DECL is the substituted VAR_DECL. Other arguments are as
17089 for tsubst. */
17091 static tree
17094 {
17103 {
17105 {
17107 {
17112 }
17113 }
17115 {
17116 /* If we had an initializer but it
17117 instantiated to nothing,
17118 value-initialize the object. This will
17119 only occur when the initializer was a
17120 pack expansion where the parameter packs
17121 used in that expansion were of length
17122 zero. */
17128 }
17129 }
17132 }
17134 /* If T is a reference to a dependent member of the current instantiation C and
17135 we are trying to refer to that member in a partial instantiation of C,
17136 return a SCOPE_REF; otherwise, return NULL_TREE.
17138 This can happen when forming a C++17 deduction guide, as in PR96199. */
17140 static tree
17142 tree in_decl)
17143 {
17160 {
17169 complain);
17170 }
17175 {
17181 }
17184 {
17187 /* The TYPE_DECL for a typename has DECL_CONTEXT of the typename
17188 scope, but it doesn't need to be rewritten again. */
17192 }
17196 else
17199 }
17201 /* Like tsubst, but deals with expressions. This function just replaces
17202 template parms; to finish processing the resultant expression, use
17203 tsubst_copy_and_build or tsubst_expr. */
17205 static tree
17207 {
17209 tree r;
17223 {
17228 {
17229 /* We get here for a use of 'this' in an NSDMI. */
17233 /* This can happen for a parameter name used later in a function
17234 declaration (such as in a late-specified return type). Just
17235 make a dummy decl, since it's only used for its type. */
17238 /* Give it the template pattern as its context; its true context
17239 hasn't been instantiated yet and this is good enough for
17240 mangling. */
17242 }
17251 {
17252 tree enum_type;
17253 tree v;
17260 /* Unfortunately, we cannot just call lookup_name here.
17261 Consider:
17263 template <int I> int f() {
17264 enum E { a = I };
17265 struct S { void g() { E e = a; } };
17266 };
17268 When we instantiate f<7>::S::g(), say, lookup_name is not
17269 clever enough to find f<7>::a. */
17270 enum_type
17280 /* We didn't find the name. That should never happen; if
17281 name-lookup found it during preliminary parsing, we
17282 should find it again here during instantiation. */
17284 }
17289 {
17290 tree ctx;
17295 {
17298 {
17302 }
17304 }
17305 }
17314 {
17315 /* Local specialization will usually have been created when
17316 we instantiated the DECL_EXPR_DECL. */
17319 {
17320 /* We're in a generic lambda referencing a local extern
17321 from an outer block-scope of a non-template. */
17324 }
17325 }
17328 {
17331 {
17332 /* First try name lookup to find the instantiation. */
17335 {
17337 {
17338 /* During error-recovery we may find a non-variable,
17339 even an OVERLOAD: just bail out and avoid ICEs and
17340 duplicate diagnostics (c++/62207). */
17343 }
17345 {
17346 /* Make sure the one we found is the one we want. */
17350 }
17351 }
17355 else
17356 {
17357 /* This can happen for a variable used in a
17358 late-specified return type of a local lambda, or for a
17359 local static or constant. Building a new VAR_DECL
17360 should be OK in all those cases. */
17363 /* Avoid infinite recursion (79640). */
17366 {
17367 /* We can't call cp_finish_decl, so handle the
17368 initializer by hand. */
17383 }
17385 || processing_contract_condition
17392 }
17393 /* Remember this for subsequent uses. */
17396 }
17399 }
17400 else
17424 {
17425 /* Template template argument like the following example need
17426 special treatment:
17428 template <template <class> class TT> struct C {};
17429 template <class T> struct D {
17430 template <class U> struct E {};
17431 C<E> c; // #1
17432 };
17433 D<int> d; // #2
17435 We are processing the template argument `E' in #1 for
17436 the template instantiation #2. Originally, `E' is a
17437 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
17438 have to substitute this with one having context `D<int>'. */
17443 }
17444 else
17445 /* Ordinary template template argument. */
17450 {
17451 /* Handle location wrappers by substituting the wrapped node
17452 first, *then* reusing the resulting type. Doing the type
17453 first ensures that we handle template parameters and
17454 parameter pack expansions. */
17456 {
17460 }
17462 /* force_paren_expr can also create a VIEW_CONVERT_EXPR. */
17464 {
17469 }
17470 /* We shouldn't see any other uses of these in templates
17471 (tsubst_copy_and_build handles C++20 tparm object wrappers). */
17473 }
17481 CASE_CONVERT:
17482 {
17489 }
17492 {
17498 }
17503 {
17512 /* We only want to compute the number of arguments. */
17515 else
17522 {
17524 /* Set TREE_USED for the benefit of -Wunused. */
17528 }
17536 {
17541 else
17549 else
17554 }
17555 else
17557 }
17559 {
17567 }
17568 /* Fall through */
17584 {
17590 /* For addresses of immediate functions ensure we have EXPR_LOCATION
17591 set for possible later diagnostics. */
17598 }
17601 {
17605 {
17608 }
17610 }
17613 {
17614 tree object;
17615 tree name;
17620 {
17624 }
17627 {
17637 }
17642 in_decl);
17643 else
17646 }
17682 {
17686 }
17689 {
17694 }
17697 {
17701 }
17704 {
17712 }
17718 {
17725 }
17728 {
17735 }
17738 {
17745 }
17748 {
17749 /* Substituted template arguments */
17759 else
17761 }
17764 {
17784 }
17792 /* Fall through. */
17795 {
17798 }
17799 else
17803 /* This is handled by tsubst_copy_and_build. */
17807 {
17811 }
17814 /* We shouldn't have built any of these during initial template
17815 generation. Instead, they should be built during instantiation
17816 in response to the saved STMT_IS_FULL_EXPR_P setting. */
17820 {
17830 }
17848 {
17849 /* Instantiate any typedefs in the type. */
17854 }
17857 {
17861 {
17864 }
17866 }
17869 /* These can sometimes show up in a partial instantiation, but never
17870 involve template parms. */
17886 /* ??? There's no point in copying it for now, but maybe some
17887 day it will contain more information, such as a pointer back
17888 to the containing function, inlined copy or so. */
17895 /* We shouldn't get here, but keep going if !flag_checking. */
17899 }
17900 }
17902 /* Helper function for tsubst_omp_clauses, used for instantiation of
17903 OMP_CLAUSE_DECL of clauses. */
17905 static tree
17908 {
17912 /* Handle OpenMP iterators. */
17916 {
17917 tree ret;
17920 else
17921 {
17925 {
17939 }
17943 }
17947 }
17949 /* Handle an OpenMP array section represented as a TREE_LIST (or
17950 OMP_CLAUSE_DOACROSS_KIND). An OMP_CLAUSE_DOACROSS (with a depend
17951 kind of OMP_CLAUSE_DOACROSS_SINK) can also be represented as a
17952 TREE_LIST. We can handle it exactly the same as an array section
17953 (purpose, value, and a chain), even though the nomenclature
17954 (low_bound, length, etc) is different. */
17956 {
17957 tree low_bound
17970 }
17972 /* Undo convert_from_reference tsubst_expr could have called. */
17978 }
17980 /* Like tsubst_copy, but specifically for OpenMP clauses. */
17982 static tree
17985 {
17991 {
17997 {
18000 {
18006 }
18007 /* FALLTHRU */
18037 /* FALLTHRU */
18070 {
18073 {
18080 }
18081 else
18083 }
18110 {
18113 }
18118 else
18149 }
18152 {
18169 /* tsubst_expr on SCOPE_REF results in returning
18170 finish_non_static_data_member result. Undo that here. */
18174 {
18179 {
18183 CASE_CONVERT:
18192 /* FALLTHRU */
18196 }
18197 }
18203 {
18206 {
18209 }
18210 }
18214 }
18215 }
18219 {
18224 {
18227 }
18228 }
18230 }
18232 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
18234 static tree
18236 tree in_decl)
18237 {
18238 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
18256 {
18259 else
18260 {
18264 }
18265 }
18270 #undef RECUR
18271 }
18273 /* Used to temporarily communicate the list of #pragma omp parallel
18274 clauses to #pragma omp for instantiation if they are combined
18275 together. */
18282 /* Substitute one OMP_FOR iterator. */
18284 static bool
18288 {
18289 #define RECUR(NODE) \
18290 tsubst_expr ((NODE), args, complain, in_decl)
18302 {
18305 {
18310 {
18320 else
18322 {
18324 {
18330 }
18333 }
18334 }
18335 }
18339 }
18341 {
18342 /* We need to jump through some hoops to handle declarations in the
18343 init-statement, since we might need to handle auto deduction,
18344 but we need to keep control of initialization. */
18348 }
18349 else
18350 {
18352 {
18355 {
18359 {
18363 CASE_CONVERT:
18371 {
18374 }
18375 /* FALLTHRU */
18379 }
18380 }
18381 }
18382 else
18384 }
18386 {
18392 }
18393 else
18397 {
18403 NULL_TREE);
18404 else
18406 }
18409 {
18416 {
18421 }
18424 }
18434 {
18436 {
18437 /* Declare the variable, but don't let that initialize it. */
18442 }
18445 {
18449 {
18458 }
18459 else
18463 {
18468 }
18469 else
18473 }
18479 }
18482 {
18483 /* Declare and initialize the variable. */
18486 }
18488 {
18493 {
18495 {
18501 {
18504 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
18509 }
18512 {
18514 decl);
18516 }
18519 {
18521 decl);
18523 }
18524 else
18526 }
18529 }
18531 {
18534 ? OMP_CLAUSE_LASTPRIVATE
18539 {
18542 }
18543 }
18544 }
18547 {
18551 }
18552 else
18556 {
18567 {
18575 }
18576 else
18582 {
18588 }
18592 {
18600 }
18601 else
18607 }
18616 #undef RECUR
18617 }
18619 /* Helper function of tsubst_expr, find OMP_TEAMS inside
18620 of OMP_TARGET's body. */
18622 static tree
18624 {
18627 {
18636 }
18638 }
18640 /* Helper function for tsubst_expr. For decomposition declaration
18641 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
18642 also the corresponding decls representing the identifiers
18643 of the decomposition declaration. Return DECL if successful
18644 or error_mark_node otherwise, set *FIRST to the first decl
18645 in the list chained through DECL_CHAIN and *CNT to the number
18646 of such decls. */
18648 static tree
18652 {
18657 decl2
18662 {
18664 {
18667 }
18679 else
18680 {
18684 }
18691 {
18694 }
18695 else
18697 }
18700 }
18702 /* Return the proper local_specialization for init-capture pack DECL. */
18704 static tree
18706 {
18707 /* We handle normal pack captures by forwarding to the specialization of the
18708 captured parameter. We can't do that for pack init-captures; we need them
18709 to have their own local_specialization. We created the individual
18710 VAR_DECLs (if any) under build_capture_proxy, and we need to collect them
18711 when we process the DECL_EXPR for the pack init-capture in the template.
18712 So, how do we find them? We don't know the capture proxy pack when
18713 building the individual resulting proxies, and we don't know the
18714 individual proxies when instantiating the pack. What we have in common is
18715 the FIELD_DECL.
18717 So...when we instantiate the FIELD_DECL, we stick the result in
18718 local_specializations. Then at the DECL_EXPR we look up that result, see
18719 how many elements it has, synthesize the names, and look them up. */
18733 {
18738 }
18740 {
18745 else
18747 }
18749 }
18751 /* T is an operand of a template tree being substituted. Return whether
18752 T is dependent such that we should suppress some warnings that would
18753 make sense if the substituted expression were written directly, like
18754 template <int I> bool f() { return I == 2; }
18755 We don't want to warn when instantiating f that comparing two constants
18756 always has the same value.
18758 This is a more limited concept of dependence than instantiation-dependent;
18759 here we don't care whether substitution could fail. */
18761 static bool
18763 {
18772 }
18774 /* Like tsubst_copy for expressions, etc. but also does semantic
18775 processing. */
18777 tree
18779 {
18780 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
18781 #define RECUR(NODE) \
18782 tsubst_expr ((NODE), args, complain, in_decl)
18785 tree r;
18786 location_t loc;
18798 {
18800 {
18804 }
18833 else
18846 {
18851 }
18855 {
18857 tree init;
18863 {
18866 {
18870 {
18875 }
18877 }
18878 else
18879 {
18880 /* This is a non-dependent using-decl, and we'll have
18881 used the names it found during template parsing. We do
18882 not want to do the lookup again, because we might not
18883 find the things we found then. */
18886 /* We still need to push the bindings so that we can look up
18887 this name later. */
18890 }
18891 }
18894 {
18895 /* We're in tsubst_lambda_expr, we've already inserted a new
18896 capture proxy, so look it up and register it. */
18897 tree inst;
18899 {
18903 }
18905 {
18906 inst = (retrieve_local_specialization
18910 }
18911 else
18916 }
18923 /* Don't copy the old closure; we'll create a new one in
18924 tsubst_lambda_expr. */
18926 else
18927 {
18931 {
18932 /* By marking the declaration as instantiated, we avoid
18933 trying to instantiate it. Since instantiate_decl can't
18934 handle local variables, and since we've already done
18935 all that needs to be done, that's the right thing to
18936 do. */
18941 /* Anonymous aggregates are a special case. */
18944 {
18947 {
18951 }
18953 }
18958 {
18966 }
18967 else
18968 {
18990 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
18996 /* In a non-template function, VLA type declarations are
18997 handled in grokdeclarator; for templates, handle them
18998 now. */
19002 {
19006 asmspec_tree
19010 }
19016 }
19017 }
19018 }
19021 }
19031 {
19035 }
19040 {
19041 /* Construct another range_for, if this is not a final
19042 substitution (for inside a generic lambda of a
19043 template). Otherwise convert to a regular for. */
19045 stmt = (processing_template_decl
19062 {
19068 }
19069 else
19070 {
19076 }
19082 }
19089 {
19093 }
19099 {
19103 }
19115 {
19121 }
19124 {
19125 /* We're partially instantiating a generic lambda, but the condition
19126 of the constexpr if is still dependent. Don't substitute into the
19127 branches now, just remember the template arguments. */
19135 }
19139 {
19144 }
19145 else
19146 {
19154 }
19160 {
19170 }
19178 else
19186 else
19207 {
19213 {
19218 }
19219 }
19223 {
19225 tree label;
19232 }
19238 /* Computed goto's must be tsubst'd into. On the other hand,
19239 non-computed gotos must not be; the identifier in question
19240 will have no binding. */
19242 else
19248 {
19265 }
19270 {
19275 }
19276 else
19277 {
19282 else
19289 else
19295 else
19297 }
19301 {
19305 {
19307 /* Prevent instantiate_decl from trying to instantiate
19308 this variable. We've already done all that needs to be
19309 done. */
19312 }
19317 }
19323 {
19324 /* Local classes are not independent templates; they are
19325 instantiated along with their containing function. And this
19326 way we don't have to deal with pushing out of one local class
19327 to instantiate a member of another local class. */
19328 /* Closures are handled by the LAMBDA_EXPR. */
19332 {
19333 /* This is a partial instantiation, try again when full. */
19336 }
19350 }
19354 {
19355 tree condition;
19366 }
19373 in_decl);
19395 {
19402 }
19418 {
19432 in_decl);
19434 {
19441 }
19452 any_range_for
19459 {
19468 }
19469 else
19474 else
19481 else
19482 {
19490 }
19493 t));
19495 }
19501 /* FALLTHRU */
19511 in_decl);
19513 {
19518 }
19519 else
19520 {
19524 }
19529 {
19531 "%<#pragma omp critical%> with %<hint%> clause requires "
19534 }
19545 {
19548 {
19553 }
19554 else
19555 {
19559 }
19561 }
19562 else
19564 OMP_CLAUSE_DEPEND_INVALID,
19573 ? C_ORT_ACC
19592 {
19595 /* For combined target teams, ensure the num_teams and
19596 thread_limit clause expressions are evaluated on the host,
19597 before entering the target construct. */
19606 {
19609 tf_none);
19616 OMP_CLAUSE_FIRSTPRIVATE);
19620 }
19621 }
19658 {
19662 }
19663 else
19674 /* FALLTHRU */
19692 {
19698 {
19701 }
19703 {
19707 {
19710 }
19715 }
19716 else
19717 {
19720 }
19725 }
19726 else
19727 {
19734 {
19737 }
19740 {
19745 {
19748 }
19750 {
19754 {
19757 }
19762 }
19763 else
19764 {
19767 }
19771 }
19772 else
19773 {
19777 }
19781 }
19785 {
19791 {
19795 {
19800 }
19804 }
19805 else
19806 {
19811 }
19812 }
19816 {
19820 }
19833 /* If the first operand was a statement, we're done with it. */
19838 complain));
19854 }
19857 out:
19860 #undef RECUR
19861 #undef RETURN
19862 }
19864 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
19865 function. For description of the body see comment above
19866 cp_parser_omp_declare_reduction_exprs. */
19868 static void
19870 {
19876 tree_stmt_iterator tsi;
19887 {
19894 /* tsubsting a local var_decl leaves DECL_CONTEXT null, as we
19895 expect to be pushing it. */
19907 }
19909 {
19929 }
19930 }
19932 /* T is a postfix-expression that is not being used in a function
19933 call. Return the substituted version of T. */
19935 static tree
19937 tsubst_flags_t complain,
19938 tree in_decl)
19939 {
19943 else
19947 }
19949 /* Subroutine of tsubst_lambda_expr: add the FIELD/INIT capture pair to the
19950 LAMBDA_EXPR_CAPTURE_LIST passed in LIST. Do deduction for a previously
19951 dependent init-capture. EXPLICIT_P is true if the original list had
19952 explicit captures. */
19954 static void
19956 tsubst_flags_t complain)
19957 {
19959 {
19962 {
19966 }
19973 }
19976 }
19978 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
19979 instantiation context. Instantiating a pack expansion containing a lambda
19980 might result in multiple lambdas all based on the same lambda in the
19981 template. */
19983 tree
19985 {
20000 else
20011 {
20016 else
20028 {
20029 /* For a VLA, simply tsubsting the field type won't work, we need to
20030 go through add_capture again. XXX do we want to do this for all
20031 captures? */
20032 tree name = (get_identifier
20040 }
20047 {
20048 /* Remember these for when we've pushed local_specializations. */
20051 }
20057 {
20066 complain);
20067 }
20068 else
20069 {
20075 }
20076 }
20085 /* If we're pushed into another scope (PR105652), fix it. */
20090 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
20107 {
20110 }
20113 {
20116 }
20120 else
20121 {
20122 /* The body of a lambda-expression is not a subexpression of the
20123 enclosing expression. Parms are to have DECL_CHAIN tsubsted,
20124 which would be skipped if cp_unevaluated_operand. */
20125 cp_evaluated ev;
20127 /* Fix the type of 'this'. */
20131 tree inst = (oldtmpl
20136 {
20139 }
20145 /* Let finish_function set this. */
20151 else
20152 /* Still increment function_depth so that we don't GC in the
20153 middle of an expression. */
20163 /* Now record them for lookup_init_capture_pack. */
20166 {
20170 }
20176 {
20177 /* We might not partially instantiate some parts of the function, so
20178 copy these flags from the original template. */
20184 }
20186 /* [temp.deduct] A lambda-expression appearing in a function type or a
20187 template parameter is not considered part of the immediate context for
20188 the purposes of template argument deduction. */
20193 /* We already have a body block from start_lambda_function, we don't
20194 need another to confuse NRV (91217). */
20205 else
20208 /* The capture list was built up in reverse order; fix that now. */
20215 }
20217 out:
20223 }
20225 /* Subroutine of maybe_fold_fn_template_args. */
20227 static bool
20229 {
20232 {
20238 {
20241 }
20246 {
20250 }
20251 }
20254 }
20256 /* Try to do constant evaluation of any explicit template arguments in FN
20257 before overload resolution, to get any errors only once. Return true iff
20258 we didn't have any problems folding. */
20260 static bool
20262 {
20280 }
20282 /* Helper function for tsubst_copy_and_build CALL_EXPR and ARRAY_REF
20283 handling. */
20285 static void
20288 {
20291 {
20297 else
20298 {
20299 /* Expand the pack expansion and push each entry onto CALL_ARGS. */
20302 {
20307 {
20312 }
20313 }
20314 else
20315 /* A partial substitution. Add one entry. */
20317 }
20318 }
20319 }
20321 /* Like tsubst but deals with expressions and performs semantic
20322 analysis. */
20324 tree
20326 tree args,
20327 tsubst_flags_t complain,
20328 tree in_decl)
20329 {
20330 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
20331 #define RECUR(NODE) \
20332 tsubst_copy_and_build (NODE, args, complain, in_decl)
20335 location_t save_loc;
20344 /* N3276 decltype magic only applies to calls at the top level or on the
20345 right side of a comma. */
20350 {
20353 /* Fall through. */
20355 {
20356 tree decl;
20357 cp_id_kind idk;
20361 {
20364 }
20366 /* Look up the name. */
20369 /* By convention, expressions use ERROR_MARK_NODE to indicate
20370 failure, not NULL_TREE. */
20384 input_location);
20388 {
20392 }
20394 }
20397 {
20398 tree object;
20409 {
20414 }
20417 {
20424 /* If we built a function concept check, return the underlying
20425 template-id. So we can evaluate it as a function call. */
20430 }
20433 {
20435 complain);
20439 }
20442 {
20445 }
20446 else
20456 {
20457 /* C++20 P0846: we can encounter an IDENTIFIER_NODE here when
20458 name lookup found nothing when parsing the template name. */
20461 }
20462 else
20464 }
20467 {
20471 {
20472 /* A type conversion to reference type will be enclosed in
20473 such an indirect ref, but the substitution of the cast
20474 will have also added such an indirect ref. */
20476 }
20477 else
20486 }
20489 {
20493 }
20496 {
20500 {
20505 }
20507 /* We'll pass this to convert_nontype_argument again, we don't need
20508 to actually perform any conversion here. */
20516 flags));
20517 }
20520 {
20526 }
20533 {
20534 tree type;
20548 {
20568 }
20571 }
20574 {
20578 }
20603 {
20610 }
20613 /* convert_like should have created an IMPLICIT_CONV_EXPR. */
20624 else
20626 in_decl);
20661 {
20662 /* If either OP0 or OP1 was value- or type-dependent, suppress
20663 warnings that depend on the range of the types involved. */
20677 tree r = build_x_binary_op
20679 op0,
20681 ? ERROR_MARK
20683 op1,
20685 ? ERROR_MARK
20694 }
20697 {
20705 }
20721 {
20723 releasing_vec index_exp_list;
20725 index_exp_list);
20727 tree r;
20733 else
20738 }
20747 /* Fall through */
20750 {
20751 tree r;
20759 {
20760 /* When there are no ARGS, we are trying to evaluate a
20761 non-dependent expression from the parser. Trying to do
20762 the substitutions may not work. */
20765 }
20766 else
20767 {
20772 else
20776 }
20781 else
20786 {
20788 {
20790 {
20794 }
20795 else
20799 }
20801 }
20803 }
20806 {
20814 }
20828 {
20833 tree r = build_x_modify_expr
20837 /* TREE_NO_WARNING must be set if either the expression was
20838 parenthesized or it uses an operator such as >>= rather
20839 than plain assignment. In the former case, it was already
20840 set and must be copied. In the latter case,
20841 build_x_modify_expr sets it and it must not be reset
20842 here. */
20847 }
20852 /* Remember that there was a reference to this entity. */
20859 {
20864 tree ret;
20871 else
20872 {
20876 }
20878 /* If there was an initializer in the original tree, but it
20879 instantiated to an empty list, then we should pass a
20880 non-NULL empty vector to tell build_new that it was an
20881 empty initializer() rather than no initializer. This can
20882 only happen when the initializer is a pack expansion whose
20883 parameter packs are of length zero. */
20888 else
20889 {
20893 else
20894 {
20897 }
20898 }
20900 /* Avoid passing an enclosing decl to valid_array_size_p. */
20907 complain);
20915 }
20918 {
20924 complain));
20925 }
20928 {
20932 op0,
20936 }
20939 {
20940 tree function;
20944 tree ret;
20947 /* Internal function with no arguments. */
20951 /* When we parsed the expression, we determined whether or
20952 not Koenig lookup should be performed. */
20955 {
20958 }
20960 {
20965 }
20970 {
20971 /* Do nothing; calling tsubst_copy_and_build on an identifier
20972 would incorrectly perform unqualified lookup again.
20974 Note that we can also have an IDENTIFIER_NODE if the earlier
20975 unqualified lookup found a dependent local extern declaration
20976 (as per finish_call_expr); in that case koenig_p will be false
20977 and we do want to do the lookup again to find the substituted
20978 declaration. */
20982 /* Use tsubst_copy to substitute through the template arguments
20983 of the template-id without performing unqualified lookup of
20984 the template name. */
20986 }
20987 else
20988 {
20990 {
20996 }
20997 else
21002 /* Avoid error about taking the address of a constructor. */
21007 /* When KOENIG_P, we don't want to mark_used the callee before
21008 augmenting the overload set via ADL, so during this initial
21009 substitution we disable mark_used by setting tf_conv (68942). */
21015 }
21018 releasing_vec call_args;
21020 call_args);
21022 /* Stripped-down processing for a call in a thunk. Specifically, in
21023 the thunk template for a generic lambda. */
21025 {
21026 /* Now that we've expanded any packs, the number of call args
21027 might be different. */
21031 {
21038 }
21039 /* We aren't going to do normal overload resolution, so force the
21040 template-id to resolve. */
21043 {
21044 /* In a thunk, pass through args directly, without any
21045 conversions. */
21050 }
21052 {
21053 /* If there are no other args, just push 'this'. */
21056 else
21057 {
21058 /* Otherwise, shift the other args over to make room. */
21064 }
21065 }
21068 /* The thunk location is not interesting. */
21075 }
21077 /* We do not perform argument-dependent lookup if normal
21078 lookup finds a non-function, in accordance with the
21079 resolution of DR 218. */
21082 /* If lookup found a member function, the Koenig lookup is
21083 not appropriate, even if an unqualified-name was used
21084 to denote the function. */
21087 /* C++20 P0846: Lookup found nothing. */
21090 /* Only do this when substitution turns a dependent call
21091 into a non-dependent call. */
21103 {
21108 {
21109 /* For backwards compatibility and good diagnostics, try
21110 the unqualified lookup again if we aren't in SFINAE
21111 context. */
21118 {
21121 "and no declarations were found by "
21122 "argument-dependent lookup at the point "
21127 /* In a lambda fn, we have to be careful to not
21128 introduce new this captures. Legacy code can't
21129 be using lambdas anyway, so it's ok to be
21130 stricter. Be strict with C++20 template-id ADL too.
21131 And be strict if we're already failing anyway. */
21137 else
21141 {
21152 {
21155 "declarations in dependent base %qT are "
21161 else
21165 }
21166 else
21168 "%qD declared here, later in the "
21172 }
21175 }
21176 }
21178 {
21182 }
21183 }
21185 /* Remember that there was a reference to this entity. */
21194 /* Put back tf_decltype for the actual call. */
21199 {
21203 {
21205 "wrong number of arguments to "
21208 }
21209 else
21217 {
21219 "wrong number of arguments to "
21223 }
21227 complain);
21233 {
21235 complain);
21239 }
21244 {
21246 "wrong number of arguments to "
21249 }
21250 else
21251 {
21256 {
21259 }
21262 }
21266 /* Unsupported internal function with arguments. */
21268 }
21273 complain);
21275 {
21290 complain);
21291 else
21292 ret = (build_new_method_call
21297 complain));
21298 }
21300 {
21301 /* FUNCTION is a template-id referring to a concept definition. */
21306 /* Calls to standard and variable concepts should have been
21307 previously diagnosed. */
21310 /* Ensure the result is wrapped as a call expression. */
21312 }
21313 else
21316 koenig_p,
21317 complain);
21320 {
21326 {
21330 }
21332 /* This also suppresses -Wredundant-move. */
21334 }
21337 }
21340 {
21347 {
21349 {
21354 }
21355 else
21356 {
21361 }
21363 }
21364 else
21365 {
21368 }
21373 }
21376 {
21381 input_location));
21382 }
21388 {
21389 tree object;
21390 tree object_type;
21391 tree member;
21392 tree r;
21396 /* Remember that there was a reference to this entity. */
21407 else
21414 {
21417 }
21419 {
21421 complain);
21425 }
21429 {
21431 {
21436 {
21439 }
21441 {
21446 }
21447 }
21448 }
21451 {
21452 /* Lookup the template functions now that we know what the
21453 scope is. */
21460 {
21463 args);
21464 member = (adjust_result_of_qualified_name_lookup
21466 object_type));
21467 }
21468 else
21469 {
21471 input_location);
21473 }
21474 }
21478 {
21480 {
21484 else
21487 }
21489 }
21493 complain);
21497 }
21504 {
21511 tree r;
21520 /* We do not want to process the index of aggregate
21521 initializers as they are identifier nodes which will be
21522 looked up by digest_init. */
21526 {
21529 }
21534 {
21536 /* An identifier index is looked up in the type
21537 being initialized, not the current scope. */
21542 {
21543 /* Substitute into the pack expansion. */
21545 in_decl);
21549 ;
21551 /* Just move the argument into place. */
21553 else
21554 {
21555 /* Update the length of the final CONSTRUCTOR
21556 arguments vector, and note that we will need to
21557 copy.*/
21560 }
21561 }
21562 else
21564 }
21567 {
21572 {
21574 {
21579 }
21580 else
21582 }
21583 }
21591 {
21596 }
21600 }
21603 {
21606 {
21609 }
21610 else
21611 {
21614 }
21615 }
21620 /* Fall through */
21623 {
21625 /* ??? We're doing a subset of finish_id_expression here. */
21627 /* Replace an evaluated use of the thread_local variable with
21628 a call to its wrapper. */
21634 /* If the original type was a reference, we'll be wrapped in
21635 the appropriate INDIRECT_REF. */
21638 }
21641 {
21645 }
21648 {
21649 tree object_ptr
21655 }
21662 {
21669 }
21672 {
21681 /* If the resulting list of expression statement is empty,
21682 fold it further into void_node. */
21687 }
21690 {
21692 {
21693 /* We don't have a full set of template arguments yet; don't touch
21694 the lambda at all. */
21697 }
21701 }
21709 else
21710 /* Recreate the PAREN_EXPR from __builtin_assoc_barrier. */
21711 {
21715 }
21718 {
21723 complain));
21724 }
21727 {
21730 }
21733 /* No need to substitute further, a RANGE_EXPR will always be built
21734 with constant operands. */
21739 {
21743 /* We need to do this here as well as in tsubst_copy so we get the
21744 other tsubst_copy_and_build semantics for a PARM_DECL operand. */
21749 /* force_paren_expr can also create a VIEW_CONVERT_EXPR. */
21752 /* Otherwise, we're dealing with a wrapper to make a C++20 template
21753 parameter object const. */
21756 {
21757 /* The template argument is not const, presumably because
21758 it is still dependent, and so not the const template parm
21759 object. */
21763 {
21764 /* Don't add a wrapper to these. */
21767 }
21768 else
21769 /* Do add a wrapper otherwise (in particular, if op is
21770 another TEMPLATE_PARM_INDEX). */
21772 }
21774 }
21777 /* Handle Objective-C++ constructs, if appropriate. */
21778 {
21779 tree subst
21783 }
21785 }
21787 #undef RECUR
21788 #undef RETURN
21789 out:
21792 }
21794 /* Verify that the instantiated ARGS are valid. For type arguments,
21795 make sure that the type's linkage is ok. For non-type arguments,
21796 make sure they are constants if they are integral or enumerations.
21797 Emit an error under control of COMPLAIN, and return TRUE on error. */
21799 static bool
21801 {
21805 {
21815 }
21817 {
21818 /* [basic.link]: A name with no linkage (notably, the name
21819 of a class or enumeration declared in a local scope)
21820 shall not be used to declare an entity with linkage.
21821 This implies that names with no linkage cannot be used as
21822 template arguments
21824 DR 757 relaxes this restriction for C++0x. */
21829 {
21830 /* DR 488 makes use of a type with no linkage cause
21831 type deduction to fail. */
21833 {
21836 else
21839 }
21841 }
21842 /* In order to avoid all sorts of complications, we do not
21843 allow variably-modified types as template arguments. */
21845 {
21849 }
21850 }
21851 /* Class template and alias template arguments should be OK. */
21853 ;
21854 /* A non-type argument of integral or enumerated type must be a
21855 constant. */
21860 {
21864 }
21866 }
21868 static bool
21870 {
21875 {
21878 }
21882 }
21884 /* Call mark_used on each entity within the non-type template arguments in
21885 ARGS for an instantiation of TMPL, to ensure that each such entity is
21886 considered odr-used (and therefore marked for instantiation) regardless of
21887 whether the specialization was first formed in a template context (which
21888 inhibits mark_used).
21890 This function assumes push_to_top_level has been called beforehand. */
21892 static void
21894 {
21895 /* It suffices to do this only when instantiating a primary template. */
21899 /* We already marked outer arguments when specializing the context. */
21903 {
21904 /* A (pointer/reference to) function or variable NTTP argument. */
21907 {
21913 {
21914 /* Pass tf_none to avoid duplicate diagnostics: if this call
21915 fails then an earlier call to mark_used for this argument
21916 must have also failed and emitted a diagnostic. */
21919 }
21920 }
21921 /* A class NTTP argument. */
21924 {
21927 {
21930 }
21932 };
21935 }
21936 }
21937 }
21939 /* We're out of SFINAE context now, so generate diagnostics for the access
21940 errors we saw earlier when instantiating D from TMPL and ARGS. */
21942 static void
21944 {
21956 }
21958 /* Instantiate the indicated variable, function, or alias template TMPL with
21959 the template arguments in TARG_PTR. */
21961 tree
21963 {
21967 tree fndecl;
21968 tree gen_tmpl;
21969 tree spec;
21980 /* If this function is a clone, handle it specially. */
21982 {
21983 tree spec;
21984 tree clone;
21986 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
21987 DECL_CLONED_FUNCTION. */
21993 /* Look for the clone. */
21997 /* We should always have found the clone by now. */
22000 }
22005 /* Check to see if we already have this specialization. */
22009 /* targ_ptr only has the innermost template args, so add the outer ones
22010 from tmpl, which could be either a partial instantiation or gen_tmpl (in
22011 the case of a non-dependent call within a template definition). */
22012 targ_ptr = (add_outermost_template_args
22014 targ_ptr));
22016 /* It would be nice to avoid hashing here and then again in tsubst_decl,
22017 but it doesn't seem to be on the hot path. */
22021 || ((fndecl
22027 {
22029 {
22033 }
22035 }
22038 complain))
22041 /* We are building a FUNCTION_DECL, during which the access of its
22042 parameters and return types have to be checked. However this
22043 FUNCTION_DECL which is the desired context for access checking
22044 is not built yet. We solve this chicken-and-egg problem by
22045 deferring all checks until we have the FUNCTION_DECL. */
22048 /* Instantiation of the function happens in the context of the function
22049 template, not the context of the overload resolution we're doing. */
22051 /* If there are dependent arguments, e.g. because we're doing partial
22052 ordering, make sure processing_template_decl stays set. */
22056 {
22057 tree ctx;
22059 /* If the context of the partially instantiated template is
22060 already non-dependent, then we might as well use it. */
22062 else
22066 }
22072 {
22073 /* We need to determine if we're using a partial or explicit
22074 specialization now, because the type of the variable could be
22075 different. */
22081 {
22086 }
22087 }
22089 /* Substitute template parameters to obtain the specialization. */
22097 {
22100 }
22102 /* The DECL_TI_TEMPLATE should always be the immediate parent
22103 template, not the most general template. */
22109 /* Now we know the specialization, compute access previously
22110 deferred. Do no access control for inheriting constructors,
22111 as we already checked access for the inherited constructor. */
22114 {
22119 }
22122 /* If we've just instantiated the main entry point for a function,
22123 instantiate all the alternate entry points as well. We do this
22124 by cloning the instantiation of the main entry point, not by
22125 instantiating the template clones. */
22131 {
22133 {
22134 /* Remember to reinstantiate when we're out of SFINAE so the user
22135 can see the errors. */
22137 }
22139 }
22142 }
22144 /* Instantiate the alias template TMPL with ARGS. Also push a template
22145 instantiation level, which instantiate_template doesn't do because
22146 functions and variables have sufficient context established by the
22147 callers. */
22149 static tree
22151 {
22160 /* FIXME check for satisfaction in check_instantiated_args. */
22162 {
22164 {
22165 auto_diagnostic_group d;
22168 }
22170 }
22178 {
22179 /* An alias template specialization can be dependent
22180 even if its underlying type is not. */
22183 /* Sometimes a dependent alias spec is equivalent to its expansion,
22184 sometimes not. So always use structural_comptypes. */
22186 }
22189 }
22191 /* PARM is a template parameter pack for FN. Returns true iff
22192 PARM is used in a deducible way in the argument list of FN. */
22194 static bool
22196 {
22199 {
22201 tree packs;
22207 {
22208 /* The template parameter pack is used in a function parameter
22209 pack. If this is the end of the parameter list, the
22210 template parameter pack is deducible. */
22213 else
22214 /* Otherwise, not. Well, it could be deduced from
22215 a non-pack parameter, but doing so would end up with
22216 a deduction mismatch, so don't bother. */
22218 }
22219 }
22220 /* The template parameter pack isn't used in any function parameter
22221 packs, but it might be used deeper, e.g. tuple<Args...>. */
22223 }
22225 /* Subroutine of fn_type_unification: check non-dependent parms for
22226 convertibility. */
22228 static int
22232 {
22233 /* Non-constructor methods need to leave a conversion for 'this', which
22234 isn't included in nargs here. */
22240 {
22246 /* For a function parameter pack that occurs at the end of the
22247 parameter-declaration-list, the type A of each remaining
22248 argument of the call is compared with the type P of the
22249 declarator-id of the function parameter pack. */
22255 /* For a function parameter pack that does not occur at the
22256 end of the parameter-declaration-list, the type of the
22257 parameter pack is a non-deduced context. */
22261 {
22269 }
22272 }
22275 }
22277 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
22278 NARGS elements of the arguments that are being used when calling
22279 it. TARGS is a vector into which the deduced template arguments
22280 are placed.
22282 Returns either a FUNCTION_DECL for the matching specialization of FN or
22283 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
22284 true, diagnostics will be printed to explain why it failed.
22286 If FN is a conversion operator, or we are trying to produce a specific
22287 specialization, RETURN_TYPE is the return type desired.
22289 The EXPLICIT_TARGS are explicit template arguments provided via a
22290 template-id.
22292 The parameter STRICT is one of:
22294 DEDUCE_CALL:
22295 We are deducing arguments for a function call, as in
22296 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
22297 deducing arguments for a call to the result of a conversion
22298 function template, as in [over.call.object].
22300 DEDUCE_CONV:
22301 We are deducing arguments for a conversion function, as in
22302 [temp.deduct.conv].
22304 DEDUCE_EXACT:
22305 We are deducing arguments when doing an explicit instantiation
22306 as in [temp.explicit], when determining an explicit specialization
22307 as in [temp.expl.spec], or when taking the address of a function
22308 template, as in [temp.deduct.funcaddr]. */
22310 tree
22312 tree explicit_targs,
22313 tree targs,
22316 tree return_type,
22317 unification_kind_t strict,
22322 {
22323 tree parms;
22324 tree fntype;
22329 /* type_unification_real will pass back any access checks from default
22330 template argument substitution. */
22332 /* We don't have all the template args yet. */
22345 full_targs = (add_outermost_template_args
22347 targs));
22352 /* In C++0x, it's possible to have a function template whose type depends
22353 on itself recursively. This is most obvious with decltype, but can also
22354 occur with enumeration scope (c++/48969). So we need to catch infinite
22355 recursion and reject the substitution at deduction time; this function
22356 will return error_mark_node for any repeated substitution.
22358 This also catches excessive recursion such as when f<N> depends on
22359 f<N-1> across all integers, and returns error_mark_node for all the
22360 substitutions back up to the initial one.
22362 This is, of course, not reentrant. */
22371 {
22372 /* [temp.deduct]
22374 The specified template arguments must match the template
22375 parameters in kind (i.e., type, nontype, template), and there
22376 must not be more arguments than there are parameters;
22377 otherwise type deduction fails.
22379 Nontype arguments must match the types of the corresponding
22380 nontype template parameters, or must be convertible to the
22381 types of the corresponding nontype parameters as specified in
22382 _temp.arg.nontype_, otherwise type deduction fails.
22384 All references in the function type of the function template
22385 to the corresponding template parameters are replaced by the
22386 specified template argument values. If a substitution in a
22387 template parameter or in the function type of the function
22388 template results in an invalid type, type deduction fails. */
22399 explicit_targs);
22401 /* Adjust any explicit template arguments before entering the
22402 substitution context. */
22403 explicit_targs
22410 /* Substitute the explicit args into the function type. This is
22411 necessary so that, for instance, explicitly declared function
22412 arguments can match null pointed constants. If we were given
22413 an incomplete set of explicit args, we must not do semantic
22414 processing during substitution as we could create partial
22415 instantiations. */
22417 {
22422 /* Dig out the actual parm. */
22425 {
22428 }
22430 {
22433 }
22436 /* No explicit argument for this template parameter. */
22439 {
22440 /* Mark the argument pack as "incomplete". We could
22441 still deduce more arguments during unification.
22442 We remove this mark in type_unification_real. */
22447 /* We have some incomplete argument packs. */
22449 }
22450 }
22453 {
22455 {
22458 }
22461 /* Ignore any access checks; we'll see them again in
22462 instantiate_template and they might have the wrong
22463 access path at this point. */
22474 }
22476 /* Place the explicitly specified arguments in TARGS. */
22482 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
22484 }
22487 {
22493 }
22498 /* Never do unification on the 'this' parameter. */
22502 {
22503 /* We're deducing for a call to the result of a template conversion
22504 function. The parms we really want are in return_type. */
22508 }
22510 {
22512 }
22514 /* We allow incomplete unification without an error message here
22515 because the standard doesn't seem to explicitly prohibit it. Our
22516 callers must be ready to deal with unification failures in any
22517 event. */
22519 /* If we aren't explaining yet, push tinst context so we can see where
22520 any errors (e.g. from class instantiations triggered by instantiation
22521 of default template arguments) come from. If we are explaining, this
22522 context is redundant. */
22524 {
22527 }
22537 /* Now that we have bindings for all of the template arguments,
22538 ensure that the arguments deduced for the template template
22539 parameters have compatible template parameter lists. We cannot
22540 check this property before we have deduced all template
22541 arguments, because the template parameter types of a template
22542 template parameter might depend on prior template parameters
22543 deduced after the template template parameter. The following
22544 ill-formed example illustrates this issue:
22546 template<typename T, template<T> class C> void f(C<5>, T);
22548 template<int N> struct X {};
22550 void g() {
22551 f(X<5>(), 5l); // error: template argument deduction fails
22552 }
22554 The template parameter list of 'C' depends on the template type
22555 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
22556 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
22557 time that we deduce 'C'. */
22560 {
22563 }
22565 deduced:
22567 /* CWG2369: Check satisfaction before non-deducible conversions. */
22569 {
22573 }
22575 /* DR 1391: All parameters have args, now check non-dependent parms for
22576 convertibility. We don't do this if all args were explicitly specified,
22577 as the standard says that we substitute explicit args immediately. */
22583 /* All is well so far. Now, check:
22585 [temp.deduct]
22587 When all template arguments have been deduced, all uses of
22588 template parameters in nondeduced contexts are replaced with
22589 the corresponding deduced argument values. If the
22590 substitution results in an invalid type, as described above,
22591 type deduction fails. */
22593 {
22596 }
22598 /* Also collect access checks from the instantiation. */
22611 /* Now perform any access checks encountered during substitution. */
22618 /* If we're looking for an exact match, check that what we got
22619 is indeed an exact match. It might not be if some template
22620 parameters are used in non-deduced contexts. But don't check
22621 for an exact match if we have dependent template arguments;
22622 in that case we're doing partial ordering, and we already know
22623 that we have two candidates that will provide the actual type. */
22625 {
22629 tree sarg
22635 {
22639 }
22641 /* add_candidates uses DEDUCE_EXACT for x.operator foo(), but args
22642 doesn't contain the trailing void, and conv fns are always (). */
22644 {
22648 }
22649 }
22651 /* After doing deduction with the inherited constructor, actually return an
22652 instantiation of the inheriting constructor. */
22658 fail:
22661 {
22663 /* Reset once we're all the way out. */
22665 }
22668 }
22670 /* Returns true iff PARM is a forwarding reference in the context of
22671 template argument deduction for TMPL. */
22673 static bool
22675 {
22676 /* [temp.deduct.call], "A forwarding reference is an rvalue reference to a
22677 cv-unqualified template parameter ..." */
22682 {
22684 /* [temp.deduct.call], "... that does not represent a template parameter
22685 of a class template (during class template argument deduction)." */
22689 {
22690 /* Since the template parameters of a synthesized guide consist of
22691 the template parameters of the class template followed by those of
22692 the constructor (if any), we can tell if PARM represents a template
22693 parameter of the class template by comparing its index with the
22694 arity of the class template. */
22699 }
22701 }
22703 }
22705 /* Adjust types before performing type deduction, as described in
22706 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
22707 sections are symmetric. PARM is the type of a function parameter
22708 or the return type of the conversion function. ARG is the type of
22709 the argument passed to the call, or the type of the value
22710 initialized with the result of the conversion function.
22711 ARG_EXPR is the original argument expression, which may be null. */
22713 static int
22715 unification_kind_t strict,
22718 tree arg_expr)
22719 {
22723 {
22728 /* Swap PARM and ARG throughout the remainder of this
22729 function; the handling is precisely symmetric since PARM
22730 will initialize ARG rather than vice versa. */
22735 /* Core issue #873: Do the DR606 thing (see below) for these cases,
22736 too, but here handle it by stripping the reference from PARM
22737 rather than by adding it to ARG. */
22742 /* Nothing else to do in this case. */
22747 }
22750 {
22751 /* [temp.deduct.call]
22753 If P is not a reference type:
22755 --If A is an array type, the pointer type produced by the
22756 array-to-pointer standard conversion (_conv.array_) is
22757 used in place of A for type deduction; otherwise,
22759 --If A is a function type, the pointer type produced by
22760 the function-to-pointer standard conversion
22761 (_conv.func_) is used in place of A for type deduction;
22762 otherwise,
22764 --If A is a cv-qualified type, the top level
22765 cv-qualifiers of A's type are ignored for type
22766 deduction. */
22771 else
22773 }
22775 /* [temp.deduct.call], "If P is a forwarding reference and the argument is
22776 an lvalue, the type 'lvalue reference to A' is used in place of A for
22777 type deduction." */
22780 /* try_one_overload doesn't provide an arg_expr, but
22781 functions are always lvalues. */
22785 /* [temp.deduct.call]
22787 If P is a cv-qualified type, the top level cv-qualifiers
22788 of P's type are ignored for type deduction. If P is a
22789 reference type, the type referred to by P is used for
22790 type deduction. */
22793 {
22796 }
22798 /* DR 322. For conversion deduction, remove a reference type on parm
22799 too (which has been swapped into ARG). */
22804 }
22806 /* Subroutine of fn_type_unification. PARM is a function parameter of a
22807 template which doesn't contain any deducible template parameters; check if
22808 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
22809 unify_one_argument. */
22811 static int
22815 {
22816 tree type;
22820 else
22828 {
22831 }
22833 {
22837 /* Avoid recalculating this in add_function_candidate. */
22838 ok = (*conv_p
22840 else
22844 }
22848 else
22850 }
22854 /* Returns true iff the expression EXPR is one from which a template
22855 argument can be deduced. In other words, if it's an undecorated
22856 use of a template non-type parameter. */
22858 static bool
22860 {
22861 /* Strip implicit conversions and implicit INDIRECT_REFs. */
22867 }
22869 /* Returns true iff the array domain DOMAIN uses a template parameter in a
22870 deducible way; that is, if it has a max value of <PARM> - 1. */
22872 static bool
22874 {
22883 }
22885 /* Returns true iff the template arguments ARGS use a template parameter
22886 in a deducible way. */
22888 static bool
22890 {
22892 {
22896 else
22897 {
22904 else
22906 }
22909 }
22911 }
22913 /* Returns true iff TYPE contains any deducible references to template
22914 parameters, as per 14.8.2.5. */
22916 static bool
22918 {
22922 /* T
22923 cv-list T
22924 TT<T>
22925 TT<i>
22926 TT<> */
22931 /* T*
22932 T&
22933 T&& */
22937 /* T[integer-constant ]
22938 type [i] */
22943 /* T type ::*
22944 type T::*
22945 T T::*
22946 T (type ::*)()
22947 type (T::*)()
22948 type (type ::*)(T)
22949 type (T::*)(T)
22950 T (type ::*)(T)
22951 T (T::*)()
22952 T (T::*)(T) */
22955 || (uses_deducible_template_parms
22958 /* template-name <T> (where template-name refers to a class template)
22959 template-name <i> (where template-name refers to a class template) */
22966 /* type (T)
22967 T()
22968 T(T) */
22970 {
22984 }
22987 }
22989 /* Subroutine of type_unification_real and unify_pack_expansion to
22990 handle unification of a single P/A pair. Parameters are as
22991 for those functions. */
22993 static int
22997 {
23004 /* We can't deduce anything from this, but we might get all the
23005 template args from other function args. */
23008 /* Implicit conversions (Clause 4) will be performed on a function
23009 argument to convert it to the type of the corresponding function
23010 parameter if the parameter type contains no template-parameters that
23011 participate in template argument deduction. */
23014 /* For function parameters with no deducible template parameters,
23015 just return. We'll check non-dependent conversions later. */
23019 {
23021 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
23022 | UNIFY_ALLOW_MORE_CV_QUAL
23036 }
23038 /* We only do these transformations if this is the top-level
23039 parameter_type_list in a call or declaration matching; in other
23040 situations (nested function declarators, template argument lists) we
23041 won't be comparing a type to an expression, and we don't do any type
23042 adjustments. */
23044 {
23046 {
23049 {
23050 /* [temp.deduct.type] A template-argument can be
23051 deduced from a pointer to function or pointer
23052 to member function argument if the set of
23053 overloaded functions does not contain function
23054 templates and at most one of a set of
23055 overloaded functions provides a unique
23056 match. */
23060 /* If a unique match was not found, this is a
23061 non-deduced context, so we still succeed. */
23063 }
23069 }
23073 }
23074 else
23079 /* For deduction from an init-list we need the actual list. */
23083 }
23085 /* for_each_template_parm callback that always returns 0. */
23087 static int
23089 {
23091 }
23093 /* for_each_template_parm any_fn callback to handle deduction of a template
23094 type argument from the type of an array bound. */
23096 static int
23098 {
23106 {
23112 }
23114 /* Keep walking. */
23116 }
23118 /* Try to deduce any not-yet-deduced template type arguments from the type of
23119 an array bound. This is handled separately from unify because 14.8.2.5 says
23120 "The type of a type parameter is only deduced from an array bound if it is
23121 not otherwise deduced." */
23123 static void
23125 {
23130 }
23132 /* Most parms like fn_type_unification.
23134 If SUBR is 1, we're being called recursively (to unify the
23135 arguments of a function or method parameter of a function
23136 template).
23138 CHECKS is a pointer to a vector of access checks encountered while
23139 substituting default template arguments. */
23141 static int
23143 tree full_targs,
23144 tree xparms,
23148 unification_kind_t strict,
23151 {
23156 tree parms;
23167 /* Reset the number of non-defaulted template arguments contained
23168 in TARGS. */
23171 again:
23176 /* Only fn_type_unification cares about terminal void. */
23183 {
23188 /* For a function parameter pack that occurs at the end of the
23189 parameter-declaration-list, the type A of each remaining
23190 argument of the call is compared with the type P of the
23191 declarator-id of the function parameter pack. */
23197 /* For a function parameter pack that does not occur at the
23198 end of the parameter-declaration-list, the type of the
23199 parameter pack is a non-deduced context. */
23206 explain_p))
23208 }
23213 {
23214 /* Unify the remaining arguments with the pack expansion type. */
23215 tree argvec;
23218 /* Allocate a TREE_VEC and copy in all of the arguments */
23223 /* Copy the parameter into parmvec. */
23229 /* Advance to the end of the list of parameters. */
23231 }
23233 /* Fail if we've reached the end of the parm list, and more args
23234 are present, and the parm list isn't variadic. */
23237 /* Fail if parms are left and they don't have default values and
23238 they aren't all deduced as empty packs (c++/57397). This is
23239 consistent with sufficient_parms_p. */
23242 {
23246 do
23247 {
23250 count++;
23252 }
23256 type_pack_p);
23257 }
23260 {
23261 tsubst_flags_t complain = (explain_p
23262 ? tf_warning_or_error
23267 {
23271 /* Clear the "incomplete" flags on all argument packs now so that
23272 substituting them into later default arguments works. */
23274 {
23277 }
23285 {
23290 }
23292 /* If this is an undeduced nontype parameter that depends on
23293 a type parameter, try another pass; its type may have been
23294 deduced from a later argument than the one from which
23295 this parameter can be deduced. */
23300 {
23303 }
23305 /* Core issue #226 (C++0x) [temp.deduct]:
23307 If a template argument has not been deduced, its
23308 default template argument, if any, is used.
23310 When we are in C++98 mode, TREE_PURPOSE will either
23311 be NULL_TREE or ERROR_MARK_NODE, so we do not need
23312 to explicitly check cxx_dialect here. */
23314 /* OK, there is a default argument. Wait until after the
23315 conversion check to do substitution. */
23318 /* If the type parameter is a parameter pack, then it will
23319 be deduced to an empty parameter pack. */
23321 {
23322 tree arg;
23325 {
23328 }
23329 else
23336 }
23339 }
23341 /* During partial ordering, we deduce dependent template args. */
23344 /* Now substitute into the default template arguments. */
23346 {
23351 {
23355 }
23370 {
23371 /* The type of this non-type parameter depends on undeduced
23372 parameters. Don't try to use its default argument yet,
23373 since we might deduce an argument for it on the next pass,
23374 but do check whether the arguments we already have cause
23375 substitution failure, so that that happens before we try
23376 later default arguments (78489). */
23379 NULL_TREE);
23383 else
23385 }
23386 else
23387 {
23388 /* Even if the call is happening in template context, getting
23389 here means it's non-dependent, and a default argument is
23390 considered a separate definition under [temp.decls], so we can
23391 do this substitution without processing_template_decl. This
23392 is important if the default argument contains something that
23393 might be instantiation-dependent like access (87480). */
23397 {
23398 /* First instatiate in template context, in case we still
23399 depend on undeduced template parameters. */
23402 NULL_TREE);
23406 /* We replaced all the tparms, substitute again out of
23407 template context. */
23409 }
23412 NULL_TREE);
23421 }
23430 {
23432 /* The position of the first default template argument,
23433 is also the number of non-defaulted arguments in TARGS.
23434 Record that. */
23437 }
23438 }
23442 }
23448 }
23450 /* Subroutine of type_unification_real. Args are like the variables
23451 at the call site. ARG is an overloaded function (or template-id);
23452 we try deducing template args from each of the overloads, and if
23453 only one succeeds, we go with that. Modifies TARGS and returns
23454 true on success. */
23456 static bool
23458 tree targs,
23459 tree parm,
23460 tree arg,
23461 unification_kind_t strict,
23464 {
23471 {
23474 }
23475 else
23479 /* Handle `&x' where `x' is some static or non-static member
23480 function name. */
23486 /* Strip baselink information. */
23491 {
23492 /* If we got some explicit template args, we need to plug them into
23493 the affected templates before we try to unify, in case the
23494 explicit args will completely resolve the templates in question. */
23501 {
23512 {
23517 {
23518 /* Instantiate the function to deduce its return type. */
23522 }
23531 {
23534 }
23535 }
23538 }
23539 /* If no templates (or more than one) are fully resolved by the
23540 explicit arguments, this template-id is a non-deduced context; it
23541 could still be OK if we deduce all template arguments for the
23542 enclosing call through other arguments. */
23545 }
23547 /* If ARG is, for example, "(0, &f)" then its type will be unknown
23548 -- but the deduction does not succeed because the expression is
23549 not just the function on its own. */
23551 else
23553 {
23558 {
23561 }
23562 }
23564 /* [temp.deduct.type] A template-argument can be deduced from a pointer
23565 to function or pointer to member function argument if the set of
23566 overloaded functions does not contain function templates and at most
23567 one of a set of overloaded functions provides a unique match.
23569 So if we found multiple possibilities, we return success but don't
23570 deduce anything. */
23573 {
23577 {
23582 /* Don't forget explicit template arguments in a pack. */
23586 }
23587 }
23592 }
23594 /* Core DR 115: In contexts where deduction is done and fails, or in
23595 contexts where deduction is not done, if a template argument list is
23596 specified and it, along with any default template arguments, identifies
23597 a single function template specialization, then the template-id is an
23598 lvalue for the function template specialization. */
23600 tree
23602 {
23615 {
23618 }
23620 {
23623 }
23625 {
23628 }
23631 {
23635 /* If we got some explicit template args, we need to plug them into
23636 the affected templates before we try to unify, in case the
23637 explicit args will completely resolve the templates in question. */
23645 {
23656 {
23659 {
23662 }
23665 {
23668 }
23669 }
23670 }
23672 {
23680 {
23681 tree base
23684 }
23688 }
23690 /* There were no good options and at least one bad one, so let the
23691 user know what the problem is. */
23693 }
23695 }
23697 /* As above, but error out if the expression remains overloaded. */
23699 tree
23701 {
23704 {
23708 }
23710 }
23712 /* Subroutine of resolve_overloaded_unification; does deduction for a single
23713 overload. Fills TARGS with any deduced arguments, or error_mark_node if
23714 different overloads deduce different arguments for a given parm.
23715 ADDR_P is true if the expression for which deduction is being
23716 performed was of the form "& fn" rather than simply "fn".
23718 Returns 1 on success. */
23720 static int
23722 tree orig_targs,
23723 tree targs,
23724 tree parm,
23725 tree arg,
23726 unification_kind_t strict,
23730 {
23732 tree tempargs;
23738 /* [temp.deduct.type] A template-argument can be deduced from a pointer
23739 to function or pointer to member function argument if the set of
23740 overloaded functions does not contain function templates and at most
23741 one of a set of overloaded functions provides a unique match.
23743 So if this is a template, just return success. */
23756 /* We don't copy orig_targs for this because if we have already deduced
23757 some template args from previous args, unify would complain when we
23758 try to deduce a template parameter for the same argument, even though
23759 there isn't really a conflict. */
23766 /* First make sure we didn't deduce anything that conflicts with
23767 explicitly specified args. */
23769 {
23776 /* Since we're unifying against ourselves, we will fill in
23777 template args used in the function parm list with our own
23778 template parms. Discard them. */
23781 {
23782 /* Check that the argument at each index of the deduced argument pack
23783 is equivalent to the corresponding explicitly specified argument.
23784 We may have deduced more arguments than were explicitly specified,
23785 and that's OK. */
23787 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
23788 that's wrong if we deduce the same argument pack from multiple
23789 function arguments: it's only incomplete the first time. */
23802 }
23805 }
23808 {
23813 }
23816 }
23818 /* PARM is a template class (perhaps with unbound template
23819 parameters). ARG is a fully instantiated type. If ARG can be
23820 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
23821 TARGS are as for unify. */
23823 static tree
23826 {
23835 /* We need to make a new template argument vector for the call to
23836 unify. If we used TARGS, we'd clutter it up with the result of
23837 the attempted unification, even if this class didn't work out.
23838 We also don't want to commit ourselves to all the unifications
23839 we've already done, since unification is supposed to be done on
23840 an argument-by-argument basis. In other words, consider the
23841 following pathological case:
23843 template <int I, int J, int K>
23844 struct S {};
23846 template <int I, int J>
23847 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
23849 template <int I, int J, int K>
23850 void f(S<I, J, K>, S<I, I, I>);
23852 void g() {
23853 S<0, 0, 0> s0;
23854 S<0, 1, 2> s2;
23856 f(s0, s2);
23857 }
23859 Now, by the time we consider the unification involving `s2', we
23860 already know that we must have `f<0, 0, 0>'. But, even though
23861 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
23862 because there are two ways to unify base classes of S<0, 1, 2>
23863 with S<I, I, I>. If we kept the already deduced knowledge, we
23864 would reject the possibility I=1. */
23872 else
23877 }
23879 /* Given a template type PARM and a class type ARG, find the unique
23880 base type in ARG that is an instance of PARM. We do not examine
23881 ARG itself; only its base-classes. If there is not exactly one
23882 appropriate base class, return NULL_TREE. PARM may be the type of
23883 a partial specialization, as well as a plain template type. Used
23884 by unify. */
23886 static enum template_base_result
23889 {
23891 tree binfo;
23897 {
23898 /* The type could not be completed. */
23901 }
23903 /* Walk in inheritance graph order. The search order is not
23904 important, and this avoids multiple walks of virtual bases. */
23906 {
23911 {
23912 /* If there is more than one satisfactory baseclass, then:
23914 [temp.deduct.call]
23916 If they yield more than one possible deduced A, the type
23917 deduction fails.
23919 applies. */
23921 {
23922 /* [temp.deduct.call]/4.3: If there is a class C that is a
23923 (direct or indirect) base class of D and derived (directly or
23924 indirectly) from a class B and that would be a valid deduced
23925 A, the deduced A cannot be B or pointer to B, respectively. */
23927 /* Ignore r. */
23931 else
23932 {
23935 }
23936 }
23939 }
23940 }
23944 }
23946 /* Returns the level of DECL, which declares a template parameter. */
23948 static int
23950 {
23952 {
23962 }
23964 }
23966 /* Decide whether ARG can be unified with PARM, considering only the
23967 cv-qualifiers of each type, given STRICT as documented for unify.
23968 Returns nonzero iff the unification is OK on that basis. */
23970 static int
23972 {
23978 {
23979 /* Although a CVR qualifier is ignored when being applied to a
23980 substituted template parameter ([8.3.2]/1 for example), that
23981 does not allow us to unify "const T" with "int&" because both
23982 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
23983 It is ok when we're allowing additional CV qualifiers
23984 at the outer level [14.8.2.1]/3,1st bullet. */
23993 }
24004 }
24006 /* Determines the LEVEL and INDEX for the template parameter PARM. */
24007 void
24009 {
24013 {
24016 }
24017 else
24018 {
24021 }
24022 }
24024 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
24025 do { \
24026 if (unify (TP, TA, P, A, S, EP)) \
24027 return 1; \
24028 } while (0)
24030 /* Unifies the remaining arguments in PACKED_ARGS with the pack
24031 expansion at the end of PACKED_PARMS. Returns 0 if the type
24032 deduction succeeds, 1 otherwise. STRICT is the same as in
24033 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
24034 function call argument list. We'll need to adjust the arguments to make them
24035 types. SUBR tells us if this is from a recursive call to
24036 type_unification_real, or for comparing two template argument
24037 lists. */
24039 static int
24043 {
24044 tree parm
24050 /* Add in any args remembered from an earlier partial instantiation. */
24058 /* Determine the parameter packs we will be deducing from the
24059 pattern, and record their current deductions. */
24062 {
24066 /* Only template parameter packs can be deduced, not e.g. function
24067 parameter packs or __bases or __integer_pack. */
24071 /* Determine the index and level of this parameter pack. */
24076 /* Keep track of the parameter packs and their corresponding
24077 argument packs. */
24080 }
24082 /* Loop through all of the arguments that have not yet been
24083 unified and unify each with the pattern. */
24085 {
24086 tree parm;
24090 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
24091 or the element of its argument pack at the current index if
24092 this argument was explicitly specified. */
24094 {
24103 {
24106 }
24108 }
24110 /* If we had explicit template arguments, substitute them into the
24111 pattern before deduction. */
24113 {
24114 /* Some arguments might still be unspecified or dependent. */
24122 NULL_TREE);
24127 }
24128 else
24131 /* Unify the pattern with the current argument. */
24133 explain_p))
24136 /* For each parameter pack, collect the deduced value. */
24138 {
24144 }
24145 }
24147 /* Verify that the results of unification with the parameter packs
24148 produce results consistent with what we've seen before, and make
24149 the deduced argument packs available. */
24151 {
24158 /* By default keep the original deduced argument pack.
24159 If necessary, more specific code is going to update the
24160 resulting deduced argument later down in this function. */
24164 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
24165 actually deduce anything. */
24173 {
24174 /* If we had fewer function args than explicit template args,
24175 just use the explicits. */
24180 }
24183 {
24184 tree result;
24185 /* Build the deduced *_ARGUMENT_PACK. */
24187 {
24190 }
24191 else
24196 /* Note the deduced argument packs for this parameter
24197 pack. */
24199 }
24203 {
24204 /* We only had the explicitly-provided arguments before, but
24205 now we have a complete set of arguments. */
24211 }
24212 else
24213 {
24217 /* During template argument deduction for the aggregate deduction
24218 candidate, the number of elements in a trailing parameter pack
24219 is only deduced from the number of remaining function
24220 arguments if it is not otherwise deduced. */
24223 /* FIXME This isn't set properly for partial instantiations. */
24229 /* Inconsistent unification of this parameter pack. */
24231 bad_old_arg,
24232 bad_new_arg);
24233 }
24234 }
24237 }
24239 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
24240 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
24241 parameters and return value are as for unify. */
24243 static int
24247 {
24248 tree parm_max;
24249 tree arg_max;
24253 /* Our representation of array types uses "N - 1" as the
24254 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
24255 not an integer constant. We cannot unify arbitrarily
24256 complex expressions, so we eliminate the MINUS_EXPRs
24257 here. */
24261 {
24264 }
24268 {
24269 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
24270 trying to unify the type of a variable with the type
24271 of a template parameter. For example:
24273 template <unsigned int N>
24274 void f (char (&) [N]);
24275 int g();
24276 void h(int i) {
24277 char a[g(i)];
24278 f(a);
24279 }
24281 Here, the type of the ARG will be "int [g(i)]", and
24282 may be a SAVE_EXPR, etc. */
24286 }
24288 /* If only one of the bounds used a MINUS_EXPR, compensate
24289 by adding one to the other bound. */
24292 integer_type_node,
24293 parm_max,
24294 integer_one_node);
24297 integer_type_node,
24298 arg_max,
24299 integer_one_node);
24303 }
24305 /* Returns whether T, a P or A in unify, is a type, template or expression. */
24309 static pa_kind_t
24311 {
24320 else
24322 }
24324 /* Deduce the value of template parameters. TPARMS is the (innermost)
24325 set of template parameters to a template. TARGS is the bindings
24326 for those template parameters, as determined thus far; TARGS may
24327 include template arguments for outer levels of template parameters
24328 as well. PARM is a parameter to a template function, or a
24329 subcomponent of that parameter; ARG is the corresponding argument.
24330 This function attempts to match PARM with ARG in a manner
24331 consistent with the existing assignments in TARGS. If more values
24332 are deduced, then TARGS is updated.
24334 Returns 0 if the type deduction succeeds, 1 otherwise. The
24335 parameter STRICT is a bitwise or of the following flags:
24337 UNIFY_ALLOW_NONE:
24338 Require an exact match between PARM and ARG.
24339 UNIFY_ALLOW_MORE_CV_QUAL:
24340 Allow the deduced ARG to be more cv-qualified (by qualification
24341 conversion) than ARG.
24342 UNIFY_ALLOW_LESS_CV_QUAL:
24343 Allow the deduced ARG to be less cv-qualified than ARG.
24344 UNIFY_ALLOW_DERIVED:
24345 Allow the deduced ARG to be a template base class of ARG,
24346 or a pointer to a template base class of the type pointed to by
24347 ARG.
24348 UNIFY_ALLOW_INTEGER:
24349 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
24350 case for more information.
24351 UNIFY_ALLOW_OUTER_LEVEL:
24352 This is the outermost level of a deduction. Used to determine validity
24353 of qualification conversions. A valid qualification conversion must
24354 have const qualified pointers leading up to the inner type which
24355 requires additional CV quals, except at the outer level, where const
24356 is not required [conv.qual]. It would be normal to set this flag in
24357 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
24358 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
24359 This is the outermost level of a deduction, and PARM can be more CV
24360 qualified at this point.
24361 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
24362 This is the outermost level of a deduction, and PARM can be less CV
24363 qualified at this point. */
24365 static int
24368 {
24370 tree targ;
24371 tree tparm;
24373 tsubst_flags_t complain = (explain_p
24374 ? tf_warning_or_error
24377 /* I don't think this will do the right thing with respect to types.
24378 But the only case I've seen it in so far has been array bounds, where
24379 signedness is the only information lost, and I think that will be
24380 okay. VIEW_CONVERT_EXPR can appear with class NTTP, thanks to
24381 finish_id_expression_1, and are also OK. */
24389 /* We can't deduce anything from this, but we might get all the
24390 template args from other function args. */
24396 /* If PARM uses template parameters, then we can't bail out here,
24397 even if ARG == PARM, since we won't record unifications for the
24398 template parameters. We might need them if we're trying to
24399 figure out which of two things is more specialized. */
24403 /* Handle init lists early, so the rest of the function can assume
24404 we're dealing with a type. */
24406 {
24407 tree elttype;
24412 /* We can only deduce from an initializer list argument if the
24413 parameter is std::initializer_list or an array; otherwise this
24414 is a non-deduced context. */
24419 else
24420 {
24422 /* Deduction is defined in terms of a single type, so just punt
24423 on the (bizarre) std::initializer_list<T...>. */
24426 }
24431 /* If ELTTYPE has no deducible template parms, skip deduction from
24433 else
24435 {
24443 {
24447 /* It should only be possible to get here for a call. */
24449 elt_strict |= maybe_adjust_types_for_deduction
24452 }
24455 explain_p);
24456 }
24460 {
24461 /* Also deduce from the length of the initializer list. */
24468 }
24470 /* If the std::initializer_list<T> deduction worked, replace the
24471 deduced A with std::initializer_list<A>. */
24473 {
24478 }
24480 }
24482 /* If parm and arg aren't the same kind of thing (template, type, or
24483 expression), fail early. */
24487 /* Immediately reject some pairs that won't unify because of
24488 cv-qualification mismatches. */
24491 /* It is the elements of the array which hold the cv quals of an array
24492 type, and the elements might be template type parms. We'll check
24493 when we recurse. */
24495 /* We check the cv-qualifiers when unifying with template type
24496 parameters below. We want to allow ARG `const T' to unify with
24497 PARM `T' for example, when computing which of two templates
24498 is more specialized, for example. */
24507 /* PMFs recurse at the same level, so don't strip this yet. */
24515 {
24519 /* In a type which contains a nested-name-specifier, template
24520 argument values cannot be deduced for template parameters used
24521 within the nested-name-specifier. */
24533 /* The PARM is not one we're trying to unify. Just check
24534 to see if it matches ARG. */
24535 {
24540 else
24542 }
24549 /* Check for mixed types and values. */
24557 {
24560 {
24561 /* First try to match ARG directly. */
24563 explain_p);
24565 {
24566 /* Otherwise, look for a suitable base of ARG, as below. */
24573 }
24574 }
24575 /* ARG must be constructed from a template class or a template
24576 template parameter. */
24581 /* Deduce arguments T, i from TT<T> or TT<i>. */
24587 /* If the template is a template template parameter, use the
24588 TEMPLATE_TEMPLATE_PARM for matching. */
24591 /* Fall through to deduce template name. */
24592 }
24596 {
24597 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
24599 /* Simple cases: Value already set, does match or doesn't. */
24604 }
24605 else
24606 {
24607 /* If PARM is `const T' and ARG is only `int', we don't have
24608 a match unless we are allowing additional qualification.
24609 If ARG is `const int' and PARM is just `T' that's OK;
24610 that binds `const int' to `T'. */
24615 /* Consider the case where ARG is `const volatile int' and
24616 PARM is `const T'. Then, T should be `volatile int'. */
24617 arg = cp_build_qualified_type
24622 /* Simple cases: Value already set, does match or doesn't. */
24628 /* Make sure that ARG is not a variable-sized array. (Note
24629 that were talking about variable-sized arrays (like
24630 `int[n]'), rather than arrays of unknown size (like
24631 `int[]').) We'll get very confused by such a type since
24632 the bound of the array is not constant, and therefore
24633 not mangleable. Besides, such types are not allowed in
24634 ISO C++, so we can do as we please here. We do allow
24635 them for 'auto' deduction, since that isn't ABI-exposed. */
24639 /* Strip typedefs as in convert_template_argument. */
24641 }
24643 /* If ARG is a parameter pack or an expansion, we cannot unify
24644 against it unless PARM is also a parameter pack. */
24649 /* If the argument deduction results is a METHOD_TYPE,
24650 then there is a problem.
24651 METHOD_TYPE doesn't map to any real C++ type the result of
24652 the deduction cannot be of that type. */
24666 {
24667 /* The PARM is not one we're trying to unify. Just check
24668 to see if it matches ARG. */
24674 }
24680 {
24684 /* We're deducing from an array bound, the type doesn't matter.
24685 This conversion should match the one below. */
24691 }
24693 /* [temp.deduct.type] If, in the declaration of a function template
24694 with a non-type template-parameter, the non-type
24695 template-parameter is used in an expression in the function
24696 parameter-list and, if the corresponding template-argument is
24697 deduced, the template-argument type shall match the type of the
24698 template-parameter exactly, except that a template-argument
24699 deduced from an array bound may be of any integral type.
24700 The non-type parameter might use already deduced type parameters. */
24703 /* We don't have enough levels of args to do any substitution. This
24705 else
24706 {
24712 {
24715 LOOKUP_NORMAL,
24719 }
24720 }
24724 /* Template-parameter dependent expression. Just accept it for now.
24725 It will later be processed in convert_template_argument. */
24726 ;
24730 /* OK. Ignore top-level quals here because a class-type template
24734 /* Convert the ARG to the type of PARM; the deduced non-type
24735 template argument must exactly match the types of the
24736 corresponding parameter. This conversion should match the
24737 one above. */
24740 {
24741 /* We haven't deduced the type of this parameter yet. */
24743 /* We deduce from array bounds in try_array_deduction. */
24746 {
24747 /* Deduce it from the non-type argument. As above, ignore
24748 top-level quals here too. */
24753 /* Now check whether the type of this parameter is still
24754 dependent, and give up if so. */
24760 }
24761 else
24762 /* Try again later. */
24764 }
24765 else
24768 /* If ARG is a parameter pack or an expansion, we cannot unify
24769 against it unless PARM is also a parameter pack. */
24774 {
24777 }
24782 {
24783 /* A pointer-to-member constant can be unified only with
24784 another constant. */
24788 /* Just unify the class member. It would be useless (and possibly
24789 wrong, depending on the strict flags) to unify also
24790 PTRMEM_CST_CLASS, because we want to be sure that both parm and
24791 arg refer to the same variable, even if through different
24792 classes. For instance:
24794 struct A { int x; };
24795 struct B : A { };
24797 Unification of &A::x and &B::x must succeed. */
24800 }
24803 {
24807 /* [temp.deduct.call]
24809 A can be another pointer or pointer to member type that can
24810 be converted to the deduced A via a qualification
24811 conversion (_conv.qual_).
24813 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
24814 This will allow for additional cv-qualification of the
24815 pointed-to types if appropriate. */
24818 /* The derived-to-base conversion only persists through one
24819 level of pointers. */
24824 }
24857 /* We have already checked cv-qualification at the top of the
24858 function. */
24862 /* As far as unification is concerned, this wins. Later checks
24863 will invalidate it if necessary. */
24866 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
24867 /* Type INTEGER_CST can come from ordinary constant template args. */
24879 {
24889 /* Check for pack expansions in the parameters. */
24891 {
24893 {
24895 /* We can unify against something with a trailing
24896 parameter pack. */
24898 else
24899 /* [temp.deduct.type]/9: If the template argument list of
24900 P contains a pack expansion that is not the last
24901 template argument, the entire template argument list
24902 is a non-deduced context. */
24904 }
24905 }
24907 /* If we don't have enough arguments to satisfy the parameters
24908 (not counting the pack expression at the end), or we have
24909 too many arguments for a parameter list that doesn't end in
24910 a pack expression, we can't unify. */
24916 /* Unify all of the parameters that precede the (optional)
24917 pack expression. */
24919 {
24924 }
24927 DEDUCE_EXACT,
24930 }
24938 {
24946 }
24951 {
24955 {
24956 /* First, we try to unify the PARM and ARG directly. */
24961 {
24962 /* Fallback to the special case allowed in
24963 [temp.deduct.call]:
24965 If P is a class, and P has the form
24966 template-id, then A can be a derived class of
24967 the deduced A. Likewise, if P is a pointer to
24968 a class of the form template-id, A can be a
24969 pointer to a derived class pointed to by the
24970 deduced A. */
24976 {
24977 /* Don't give the derived diagnostic if we're
24978 already dealing with the same template. */
24979 bool same_template
24985 }
24986 }
24987 }
24991 /* Perhaps PARM is something like S<U> and ARG is S<int>.
24992 Then, we should unify `int' and `U'. */
24994 else
24995 /* There's no chance of unification succeeding. */
25000 }
25007 {
25010 tree a;
25016 /* CV qualifications for methods can never be deduced, they must
25017 match exactly. We need to check them explicitly here,
25018 because type_unification_real treats them as any other
25019 cv-qualified parameter. */
25021 && (!check_cv_quals_for_unify
25049 {
25059 else
25060 {
25063 /* Here "less cv-qual" means the deduced arg (i.e. parm) has
25064 /more/ noexcept, since function pointer conversions are the
25065 reverse of qualification conversions. */
25070 else
25072 }
25073 }
25075 {
25076 /* As for noexcept. */
25083 else
25085 }
25088 }
25091 /* Unify a pointer to member with a pointer to member function, which
25092 deduces the type of the member as a function type. */
25094 {
25095 /* Check top-level cv qualifiers */
25103 /* Determine the type of the function we are unifying against. */
25107 }
25126 /* Matched cases are handled by the ARG == PARM test above. */
25130 /* We might get a variable as a non-type template argument in parm if the
25131 corresponding parameter is type-dependent. Make any necessary
25132 adjustments based on whether arg is a reference. */
25136 {
25141 }
25142 /* Now use the normal expression code to check whether they match. */
25153 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
25154 or TRAIT_TYPE nodes. */
25158 /* Unification fails if we hit an error node. */
25163 {
25173 }
25174 /* FALLTHRU */
25177 /* An unresolved overload is a nondeduced context. */
25183 expr:
25184 /* We must be looking at an expression. This can happen with
25185 something like:
25187 template <int I>
25188 void foo(S<I>, S<I + 2>);
25190 or
25192 template<typename T>
25193 void foo(A<T, T{}>);
25195 This is a "non-deduced context":
25197 [deduct.type]
25199 The non-deduced contexts are:
25201 --A non-type template argument or an array bound in which
25202 a subexpression references a template parameter.
25204 In these cases, we assume deduction succeeded, but don't
25205 actually infer any unifications. */
25210 else
25212 }
25213 }
25214 #undef RECUR_AND_CHECK_FAILURE
25215 \f
25216 /* Note that DECL can be defined in this translation unit, if
25217 required. */
25219 static void
25221 {
25222 tree clone;
25226 }
25228 /* Called if RESULT is explicitly instantiated, or is a member of an
25229 explicitly instantiated class. */
25231 void
25233 {
25236 /* If this entity has already been written out, it's too late to
25237 make any modifications. */
25241 /* consteval functions are never emitted. */
25246 /* For anonymous namespace we don't need to do anything. */
25248 {
25251 }
25254 /* The TREE_PUBLIC flag for function declarations will have been
25255 set correctly by tsubst. */
25259 {
25262 }
25263 else
25264 {
25267 /* Always make artificials weak. */
25270 /* For WIN32 we also want to put explicit instantiations in
25271 linkonce sections. */
25276 /* If the function has already been instantiated, clear DECL_EXTERNAL,
25277 since start_preparsed_function wouldn't have if we had an earlier
25278 extern explicit instantiation. */
25280 }
25282 /* If EXTERN_P, then this function will not be emitted -- unless
25283 followed by an explicit instantiation, at which point its linkage
25284 will be adjusted. If !EXTERN_P, then this function will be
25285 emitted here. In neither circumstance do we want
25286 import_export_decl to adjust the linkage. */
25288 }
25290 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
25291 important template arguments. If any are missing, we check whether
25292 they're important by using error_mark_node for substituting into any
25293 args that were used for partial ordering (the ones between ARGS and END)
25294 and seeing if it bubbles up. */
25296 static bool
25298 {
25302 {
25305 }
25307 {
25311 }
25313 }
25315 /* Given two function templates PAT1 and PAT2, return:
25317 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
25318 -1 if PAT2 is more specialized than PAT1.
25319 0 if neither is more specialized.
25321 LEN indicates the number of parameters we should consider
25322 (defaulted parameters should not be considered).
25324 The 1998 std underspecified function template partial ordering, and
25325 DR214 addresses the issue. We take pairs of arguments, one from
25326 each of the templates, and deduce them against each other. One of
25327 the templates will be more specialized if all the *other*
25328 template's arguments deduce against its arguments and at least one
25329 of its arguments *does* *not* deduce against the other template's
25330 corresponding argument. Deduction is done as for class templates.
25331 The arguments used in deduction have reference and top level cv
25332 qualifiers removed. Iff both arguments were originally reference
25333 types *and* deduction succeeds in both directions, an lvalue reference
25334 wins against an rvalue reference and otherwise the template
25335 with the more cv-qualified argument wins for that pairing (if
25336 neither is more cv-qualified, they both are equal). Unlike regular
25337 deduction, after all the arguments have been deduced in this way,
25338 we do *not* verify the deduced template argument values can be
25339 substituted into non-deduced contexts.
25341 The logic can be a bit confusing here, because we look at deduce1 and
25342 targs1 to see if pat2 is at least as specialized, and vice versa; if we
25343 can find template arguments for pat1 to make arg1 look like arg2, that
25344 means that arg2 is at least as specialized as arg1. */
25346 int
25348 {
25361 /* Remove the this parameter from non-static member functions. If
25362 one is a non-static member function and the other is not a static
25363 member function, remove the first parameter from that function
25364 also. This situation occurs for operator functions where we
25365 locate both a member function (with this pointer) and non-member
25366 operator (with explicit first operand). */
25368 {
25373 }
25375 {
25378 {
25379 len--;
25381 }
25382 }
25384 /* If only one is a conversion operator, they are unordered. */
25388 /* Consider the return type for a conversion function */
25390 {
25393 len++;
25394 }
25396 processing_template_decl++;
25402 /* Stop when an ellipsis is seen. */
25404 {
25415 {
25416 /* When both arguments are pack expansions, we need only
25417 unify the patterns themselves. */
25421 /* This is the last comparison we need to do. */
25423 }
25426 {
25430 }
25433 {
25437 }
25443 {
25449 /* Setup the parameter vector, which contains only ARG1. */
25452 /* Setup the argument vector, which contains the remaining
25453 arguments. */
25462 /* We cannot deduce in the other direction, because ARG1 is
25463 a pack expansion but ARG2 is not. */
25465 }
25467 {
25473 /* Setup the parameter vector, which contains only ARG1. */
25476 /* Setup the argument vector, which contains the remaining
25477 arguments. */
25486 /* We cannot deduce in the other direction, because ARG2 is
25487 a pack expansion but ARG1 is not.*/
25489 }
25491 else
25492 {
25493 /* The normal case, where neither argument is a pack
25494 expansion. */
25501 }
25503 /* If we couldn't deduce arguments for tparms1 to make arg1 match
25504 arg2, then arg2 is not as specialized as arg1. */
25510 /* "If, for a given type, deduction succeeds in both directions
25511 (i.e., the types are identical after the transformations above)
25512 and both P and A were reference types (before being replaced with
25513 the type referred to above):
25514 - if the type from the argument template was an lvalue reference and
25515 the type from the parameter template was not, the argument type is
25516 considered to be more specialized than the other; otherwise,
25517 - if the type from the argument template is more cv-qualified
25518 than the type from the parameter template (as described above),
25519 the argument type is considered to be more specialized than the other;
25520 otherwise,
25521 - neither type is more specialized than the other." */
25524 {
25526 {
25529 else
25531 }
25533 {
25538 }
25539 }
25542 /* We've failed to deduce something in either direction.
25543 These must be unordered. */
25548 /* We have already processed all of the arguments in our
25549 handing of the pack expansion type. */
25554 }
25556 /* "In most cases, all template parameters must have values in order for
25557 deduction to succeed, but for partial ordering purposes a template
25558 parameter may remain without a value provided it is not used in the
25559 types being used for partial ordering."
25561 Thus, if we are missing any of the targs1 we need to substitute into
25562 origs1, then pat2 is not as specialized as pat1. This can happen when
25563 there is a nondeduced context. */
25569 processing_template_decl--;
25571 /* If both deductions succeed, the partial ordering selects the more
25572 constrained template. */
25573 /* P2113: If the corresponding template-parameters of the
25574 template-parameter-lists are not equivalent ([temp.over.link]) or if
25575 the function parameters that positionally correspond between the two
25576 templates are not of the same type, neither template is more
25577 specialized than the other. */
25582 {
25588 }
25590 /* All things being equal, if the next argument is a pack expansion
25591 for one function but not for the other, prefer the
25592 non-variadic function. FIXME this is bogus; see c++/41958. */
25596 {
25599 }
25605 else
25607 }
25609 /* Determine which of two partial specializations of TMPL is more
25610 specialized.
25612 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
25613 to the first partial specialization. The TREE_PURPOSE is the
25614 innermost set of template parameters for the partial
25615 specialization. PAT2 is similar, but for the second template.
25617 Return 1 if the first partial specialization is more specialized;
25618 -1 if the second is more specialized; 0 if neither is more
25619 specialized.
25621 See [temp.class.order] for information about determining which of
25622 two templates is more specialized. */
25624 static int
25626 {
25627 tree targs;
25636 /* Just like what happens for functions, if we are ordering between
25637 different template specializations, we may encounter dependent
25638 types in the arguments, and we need our dependency check functions
25639 to behave correctly. */
25643 {
25646 }
25650 {
25653 }
25656 /* If both deductions succeed, the partial ordering selects the more
25657 constrained template. */
25661 /* In the case of a tie where at least one of the templates
25662 has a parameter pack at the end, the template with the most
25663 non-packed parameters wins. */
25665 && any_deductions
25668 {
25674 /* We don't count the pack expansion at the end. */
25684 }
25687 }
25689 /* Return the template arguments that will produce the function signature
25690 DECL from the function template FN, with the explicit template
25691 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
25692 also match. Return NULL_TREE if no satisfactory arguments could be
25693 found. */
25695 static tree
25697 {
25701 tree decl_arg_types;
25704 tree arg;
25708 /* Never do unification on the 'this' parameter. */
25730 }
25732 /* Return the innermost template arguments that, when applied to a partial
25733 specialization SPEC_TMPL of TMPL, yield the ARGS.
25735 For example, suppose we have:
25737 template <class T, class U> struct S {};
25738 template <class T> struct S<T*, int> {};
25740 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
25741 partial specialization and the ARGS will be {double*, int}. The resulting
25742 vector will be {double}, indicating that `T' is bound to `double'. */
25744 static tree
25746 {
25748 tree spec_args
25751 tree deduced_args;
25752 tree innermost_deduced_args;
25756 {
25760 innermost_deduced_args);
25761 }
25762 else
25766 again:
25775 {
25777 {
25783 }
25785 }
25788 {
25791 }
25793 /* Verify that nondeduced template arguments agree with the type
25794 obtained from argument deduction.
25796 For example:
25798 struct A { typedef int X; };
25799 template <class T, class U> struct C {};
25800 template <class T> struct C<T, typename T::X> {};
25802 Then with the instantiation `C<A, int>', we can deduce that
25803 `T' is `A' but unify () does not check whether `typename T::X'
25804 is `int'. */
25815 /* We only need to check the innermost arguments; the other
25816 arguments will always agree. */
25821 /* Now that we have bindings for all of the template arguments,
25822 ensure that the arguments deduced for the template template
25823 parameters have compatible template parameter lists. See the use
25824 of template_template_parm_bindings_ok_p in fn_type_unification
25825 for more information. */
25830 }
25832 // Compare two function templates T1 and T2 by deducing bindings
25833 // from one against the other. If both deductions succeed, compare
25834 // constraints to see which is more constrained.
25835 static int
25837 {
25842 {
25845 }
25848 {
25851 }
25853 // If both deductions succeed, then one may be more constrained.
25858 }
25860 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
25861 Return the TREE_LIST node with the most specialized template, if
25862 any. If there is no most specialized template, the error_mark_node
25863 is returned.
25865 Note that this function does not look at, or modify, the
25866 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
25867 returned is one of the elements of INSTANTIATIONS, callers may
25868 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
25869 and retrieve it from the value returned. */
25871 tree
25873 {
25880 {
25886 {
25887 /* Equally specialized, move to next function. If there
25888 is no next function, nothing's most specialized. */
25893 }
25894 }
25897 /* Now verify that champ is better than everything earlier in the
25898 instantiation list. */
25901 {
25904 }
25905 }
25907 processing_template_decl--;
25913 }
25915 /* If DECL is a specialization of some template, return the most
25916 general such template. Otherwise, returns NULL_TREE.
25918 For example, given:
25920 template <class T> struct S { template <class U> void f(U); };
25922 if TMPL is `template <class U> void S<int>::f(U)' this will return
25923 the full template. This function will not trace past partial
25924 specializations, however. For example, given in addition:
25926 template <class T> struct S<T*> { template <class U> void f(U); };
25928 if TMPL is `template <class U> void S<int*>::f(U)' this will return
25929 `template <class T> template <class U> S<T*>::f(U)'. */
25931 tree
25933 {
25935 {
25938 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
25939 template friend, or a FIELD_DECL for a capture pack. */
25942 }
25944 /* Look for more and more general templates. */
25946 {
25947 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
25948 (See cp-tree.h for details.) */
25957 /* Stop if we run into an explicitly specialized class template. */
25964 }
25967 }
25969 /* Return the most specialized of the template partial specializations
25970 which can produce TARGET, a specialization of some class or variable
25971 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
25972 a TEMPLATE_DECL node corresponding to the partial specialization, while
25973 the TREE_PURPOSE is the set of template arguments that must be
25974 substituted into the template pattern in order to generate TARGET.
25976 If the choice of partial specialization is ambiguous, a diagnostic
25977 is issued, and the error_mark_node is returned. If there are no
25978 partial specializations matching TARGET, then NULL_TREE is
25979 returned, indicating that the primary template should be used. */
25981 tree
25983 {
25986 {
25991 }
25993 {
25997 }
25999 {
26004 }
26005 else
26011 /* There are no partial specializations of this template. */
26017 /* For determining which partial specialization to use, only the
26018 innermost args are interesting. */
26021 {
26024 }
26026 /* The caller hasn't called push_to_top_level yet, but we need
26027 get_partial_spec_bindings to be done in non-template context so that we'll
26028 fully resolve everything. */
26029 processing_template_decl_sentinel ptds;
26033 {
26036 tree spec_tmpl;
26038 {
26039 /* Substitute in the template args from the enclosing class. */
26045 }
26046 else
26051 {
26055 /* Keep the candidate only if its constraints are satisfied. */
26057 {
26060 }
26061 }
26062 }
26070 {
26073 ;
26074 else
26075 {
26077 {
26080 {
26083 }
26084 }
26086 }
26087 }
26091 {
26094 {
26097 }
26098 }
26101 {
26108 else
26112 {
26117 }
26120 }
26123 }
26125 /* Explicitly instantiate DECL. */
26127 void
26129 {
26134 /* An error occurred, for which grokdeclarator has already issued
26135 an appropriate message. */
26138 {
26141 }
26143 {
26146 else
26149 }
26155 {
26156 /* There is an asymmetry here in the way VAR_DECLs and
26157 FUNCTION_DECLs are handled by grokdeclarator. In the case of
26158 the latter, the DECL we get back will be marked as a
26159 template instantiation, and the appropriate
26160 DECL_TEMPLATE_INFO will be set up. This does not happen for
26161 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
26162 should handle VAR_DECLs as it currently handles
26163 FUNCTION_DECLs. */
26165 {
26168 }
26171 {
26174 }
26176 {
26181 }
26182 }
26184 {
26187 }
26188 else
26191 /* Check for various error cases. Note that if the explicit
26192 instantiation is valid the RESULT will currently be marked as an
26193 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
26194 until we get here. */
26197 {
26198 /* DR 259 [temp.spec].
26200 Both an explicit instantiation and a declaration of an explicit
26201 specialization shall not appear in a program unless the explicit
26202 instantiation follows a declaration of the explicit specialization.
26204 For a given set of template parameters, if an explicit
26205 instantiation of a template appears after a declaration of an
26206 explicit specialization for that template, the explicit
26207 instantiation has no effect. */
26209 }
26211 {
26212 /* [temp.spec]
26214 No program shall explicitly instantiate any template more
26215 than once.
26217 We check DECL_NOT_REALLY_EXTERN so as not to complain when
26218 the first instantiation was `extern' and the second is not,
26219 and EXTERN_P for the opposite case. */
26222 /* If an "extern" explicit instantiation follows an ordinary
26223 explicit instantiation, the template is instantiated. */
26226 }
26228 {
26231 }
26233 {
26236 }
26239 ;
26241 {
26244 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
26247 }
26248 else
26256 }
26258 static void
26260 {
26266 {
26269 }
26270 }
26272 /* Perform an explicit instantiation of template class T. STORAGE, if
26273 non-null, is the RID for extern, inline or static. COMPLAIN is
26274 nonzero if this is called from the parser, zero if called recursively,
26275 since the standard is unclear (as detailed below). */
26277 void
26279 {
26281 {
26285 else
26288 }
26293 {
26296 t);
26298 }
26300 /* At most one of these will be true. */
26306 {
26308 {
26311 "ISO C++ 1998 forbids the use of %<extern%> on "
26313 }
26314 else
26316 "ISO C++ forbids the use of %qE"
26325 else
26327 storage);
26328 }
26331 /* DR 259 [temp.spec].
26333 Both an explicit instantiation and a declaration of an explicit
26334 specialization shall not appear in a program unless the
26335 explicit instantiation follows a declaration of the explicit
26336 specialization.
26338 For a given set of template parameters, if an explicit
26339 instantiation of a template appears after a declaration of an
26340 explicit specialization for that template, the explicit
26341 instantiation has no effect. */
26345 {
26346 /* We've already instantiated the template. */
26348 /* [temp.spec]
26350 No program shall explicitly instantiate any template more
26351 than once.
26353 If EXTERN_P then this is ok. */
26359 }
26367 /* In contrast to implicit instantiation, where only the
26368 declarations, and not the definitions, of members are
26369 instantiated, we have here:
26371 [temp.explicit]
26373 An explicit instantiation that names a class template
26374 specialization is also an explicit instantiation of the same
26375 kind (declaration or definition) of each of its members (not
26376 including members inherited from base classes and members
26377 that are templates) that has not been previously explicitly
26378 specialized in the translation unit containing the explicit
26379 instantiation, provided that the associated constraints, if
26380 any, of that member are satisfied by the template arguments
26381 of the explicit instantiation. */
26385 && !static_p
26389 {
26394 }
26396 {
26402 }
26403 }
26405 /* Given a function DECL, which is a specialization of TMPL, modify
26406 DECL to be a re-instantiation of TMPL with the same template
26407 arguments. TMPL should be the template into which tsubst'ing
26408 should occur for DECL, not the most general template.
26410 One reason for doing this is a scenario like this:
26412 template <class T>
26413 void f(const T&, int i);
26415 void g() { f(3, 7); }
26417 template <class T>
26418 void f(const T& t, const int i) { }
26420 Note that when the template is first instantiated, with
26421 instantiate_template, the resulting DECL will have no name for the
26422 first parameter, and the wrong type for the second. So, when we go
26423 to instantiate the DECL, we regenerate it. */
26425 static void
26427 {
26428 /* The arguments used to instantiate DECL, from the most general
26429 template. */
26432 /* Make sure that we can see identifiers, and compute access correctly. */
26436 {
26437 tree specs;
26441 /* Don't bother with this for unique friends that can't be redeclared and
26442 might change type if regenerated (PR69836). */
26446 /* Use the source location of the definition. */
26454 /* Instantiate a dynamic exception-specification. noexcept will be
26455 handled below. */
26458 {
26464 specs);
26465 }
26467 /* Merge parameter declarations. */
26471 {
26478 }
26481 {
26482 /* If we're regenerating a specialization, the contracts will have
26483 been copied from the most general template. Replace those with
26484 the ones from the actual specialization. */
26487 {
26490 }
26493 }
26495 /* Merge additional specifiers from the CODE_PATTERN. */
26501 }
26503 {
26512 }
26513 else
26516 done:
26518 }
26520 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
26521 substituted to get DECL. */
26523 tree
26525 {
26528 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
26529 for the instantiation. This is not always the most general
26530 template. Consider, for example:
26532 template <class T>
26533 struct S { template <class U> void f();
26534 template <> void f<int>(); };
26536 and an instantiation of S<double>::f<int>. We want TD to be the
26537 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
26539 more general template. */
26541 /* We must also deal with friend templates. Given:
26543 template <class T> struct S {
26544 template <class U> friend void f() {};
26545 };
26547 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
26548 so far as the language is concerned, but that's still
26549 where we get the pattern for the instantiation from. On
26550 other hand, if the definition comes outside the class, say:
26552 template <class T> struct S {
26553 template <class U> friend void f();
26554 };
26555 template <class U> friend void f() {}
26557 we don't need to look any further. That's what the check for
26558 DECL_INITIAL is for. */
26562 {
26563 /* The present template, TD, should not be a definition. If it
26564 were a definition, we should be using it! Note that we
26565 cannot restructure the loop to just keep going until we find
26566 a template with a definition, since that might go too far if
26567 a specialization was declared, but not defined. */
26569 /* Fetch the more general template. */
26571 }
26574 }
26576 /* Returns true if we need to instantiate this template instance even if we
26577 know we aren't going to emit it. */
26579 bool
26581 {
26582 /* We always instantiate inline functions so that we can inline them. An
26583 explicit instantiation declaration prohibits implicit instantiation of
26584 non-inline functions. With high levels of optimization, we would
26585 normally inline non-inline functions -- but we're not allowed to do
26586 that for "extern template" functions. Therefore, we check
26587 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
26591 /* And we need to instantiate static data members so that
26592 their initializers are available in integral constant
26593 expressions. */
26596 }
26598 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
26599 instantiate it now, modifying TREE_TYPE (fn). Returns false on
26600 error, true otherwise. */
26602 bool
26604 {
26608 /* Don't instantiate a noexcept-specification from template context. */
26618 {
26620 /* We're in start_preparsed_function, keep going. */
26627 }
26638 /* For a member friend template we can get a TEMPLATE_DECL. Let's use
26639 its FUNCTION_DECL for the rest of this function -- push_access_scope
26640 doesn't accept TEMPLATE_DECLs. */
26642 {
26645 }
26648 {
26653 }
26655 {
26659 {
26662 /* This might have failed because of an unparsed DMI, so
26663 let's try again later. */
26665 }
26667 {
26668 /* If hash_set::add returns true, the element was already there. */
26673 fn);
26675 }
26677 {
26685 {
26686 /* If needed, set current_class_ptr for the benefit of
26687 tsubst_copy/PARM_DECL. */
26692 }
26694 /* If this function is represented by a TEMPLATE_DECL, then
26695 the deferred noexcept-specification might still contain
26696 dependent types, even after substitution. And we need the
26697 dependency check functions to work in build_noexcept_spec. */
26701 /* Do deferred instantiation of the noexcept-specifier. */
26706 /* Build up the noexcept-specification. */
26716 }
26717 else
26722 }
26725 {
26726 /* This failed with a hard error, so let's go with false. */
26729 }
26736 }
26738 /* We're starting to process the function INST, an instantiation of PATTERN;
26739 add their parameters to local_specializations. */
26741 void
26743 {
26747 {
26751 }
26753 {
26755 {
26758 }
26759 else
26760 {
26761 /* Register the (value) argument pack as a specialization of
26762 TMPL_PARM, then move on. */
26765 }
26766 }
26768 }
26770 /* Instantiate the body of D using PATTERN with ARGS. We have
26771 already determined PATTERN is the correct template to use.
26772 NESTED_P is true if this is a nested function, in which case
26773 PATTERN will be a FUNCTION_DECL not a TEMPLATE_DECL. */
26775 static void
26777 {
26782 {
26785 }
26786 else
26787 /* Only OMP reductions are nested. */
26799 {
26800 /* The variable might be a lambda's extra scope, and that
26801 lambda's visibility depends on D's. */
26804 }
26806 /* Mark D as instantiated so that recursive calls to
26807 instantiate_decl do not try to instantiate it again. */
26811 /* Regenerate the declaration in case the template has been modified
26812 by a subsequent redeclaration. */
26815 /* We already set the file and line above. Reset them now in case
26816 they changed as a result of calling regenerate_decl_from_template. */
26820 {
26821 /* Clear out DECL_RTL; whatever was there before may not be right
26822 since we've reset the type of the declaration. */
26826 /* The initializer is placed in DECL_INITIAL by
26827 regenerate_decl_from_template so we don't need to
26828 push/pop_access_scope again here. Pull it out so that
26829 cp_finish_decl can process it. */
26835 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
26836 initializer. That function will defer actual emission until
26837 we have a chance to determine linkage. */
26840 /* Enter the scope of D so that access-checking works correctly. */
26850 }
26854 {
26855 /* Set up the list of local specializations. */
26859 /* Set up context. */
26862 else
26863 {
26867 }
26869 /* Create substitution entries for the parameters. */
26872 /* Substitute into the body of the function. */
26876 else
26877 {
26881 /* Set the current input_location to the end of the function
26882 so that finish_function knows where we are. */
26883 input_location
26886 /* Remember if we saw an infinite loop in the template. */
26887 current_function_infinite_loop
26889 }
26891 /* Finish the function. */
26894 else
26895 {
26898 }
26902 }
26904 /* We're not deferring instantiation any more. */
26912 }
26914 /* Produce the definition of D, a _DECL generated from a template. If
26915 DEFER_OK is true, then we don't have to actually do the
26916 instantiation now; we just have to do it sometime. Normally it is
26917 an error if this is an explicit instantiation but D is undefined.
26918 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
26919 instantiated class template. */
26921 tree
26923 {
26925 tree gen_args;
26926 tree args;
26927 tree td;
26928 tree code_pattern;
26929 tree spec;
26930 tree gen_tmpl;
26938 /* This function should only be used to instantiate templates for
26939 functions and static member variables. */
26942 /* A concept is never instantiated. */
26948 /* We may have a pending instantiation of D itself. */
26951 /* Variables are never deferred; if instantiation is required, they
26952 are instantiated right away. That allows for better code in the
26953 case that an expression refers to the value of the variable --
26954 if the variable has a constant value the referring expression can
26955 take advantage of that fact. */
26959 /* Don't instantiate cloned functions. Instead, instantiate the
26960 functions they cloned. */
26969 /* D has already been instantiated or explicitly specialized, so
26970 there's nothing for us to do here.
26972 It might seem reasonable to check whether or not D is an explicit
26973 instantiation, and, if so, stop here. But when an explicit
26974 instantiation is deferred until the end of the compilation,
26975 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
26976 the instantiation. */
26979 /* Check to see whether we know that this template will be
26980 instantiated in some other file, as with "extern template"
26981 extension. */
26984 /* In general, we do not instantiate such templates. */
26991 /* We should already have the extra args. */
26995 /* And what's in the hash table should match D. */
26997 == d
27000 /* This needs to happen before any tsubsting. */
27006 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
27007 for the instantiation. */
27012 {
27013 /* Look up an explicit specialization, if any. */
27016 {
27019 }
27020 }
27024 /* We should never be trying to instantiate a member of a class
27025 template or partial specialization. */
27030 /* In the case of a friend template whose definition is provided
27031 outside the class, we may have too many arguments. Drop the
27032 ones we don't need. The same is true for specializations. */
27033 args = get_innermost_template_args
27037 {
27043 }
27044 else
27045 {
27049 else
27051 }
27053 /* We may be in the middle of deferred access check. Disable it now. */
27056 /* Unless an explicit instantiation directive has already determined
27057 the linkage of D, remember that a definition is available for
27058 this entity. */
27068 /* If D is a member of an explicitly instantiated class template,
27069 and no definition is available, treat it like an implicit
27070 instantiation. */
27073 {
27074 /* Leave linkage flags alone on instantiations with anonymous
27075 visibility. */
27077 {
27080 }
27082 }
27084 /* Defer all other templates, unless we have been explicitly
27085 forbidden from doing so. */
27087 template. */
27088 ! pattern_defined
27089 /* If it's OK to postpone instantiation, do so. */
27090 || defer_ok
27091 /* If this is a static data member that will be defined
27092 elsewhere, we don't want to instantiate the entire data
27093 member, but we do want to instantiate the initializer so that
27094 we can substitute that elsewhere. */
27096 /* Handle here a deleted function too, avoid generating
27097 its body (c++/61080). */
27099 {
27100 /* The definition of the static data member is now required so
27101 we must substitute the initializer. */
27105 {
27106 tree ns;
27107 tree init;
27116 args,
27118 /* If instantiating the initializer involved instantiating this
27119 again, don't call cp_finish_decl twice. */
27121 {
27122 /* Make sure the initializer is still constant, in case of
27123 circular dependency (template/instantiate6.C). */
27124 const_init
27128 }
27132 }
27134 /* We restore the source position here because it's used by
27135 add_pending_template. */
27141 /* [temp.explicit]
27143 The definition of a non-exported function template, a
27144 non-exported member function template, or a non-exported
27145 member function or static data member of a class template
27146 shall be present in every translation unit in which it is
27147 explicitly instantiated. */
27151 /* If we're in unevaluated context, we just wanted to get the
27152 constant value; this isn't an odr use, so don't queue
27153 a full instantiation. */
27155 /* ??? Historically, we have instantiated inline functions, even
27156 when marked as "extern template". */
27159 }
27160 else
27161 {
27166 }
27175 }
27177 /* Run through the list of templates that we wish we could
27178 instantiate, and instantiate any we can. RETRIES is the
27179 number of times we retry pending template instantiation. */
27181 void
27183 {
27187 /* Instantiating templates may trigger vtable generation. This in turn
27188 may require further template instantiations. We place a limit here
27189 to avoid infinite loop. */
27191 {
27195 "template instantiation depth exceeds maximum of %d"
27196 " instantiating %q+D, possibly from virtual table generation"
27200 /* Pretend that we defined it. */
27203 }
27205 do
27206 {
27211 {
27216 {
27218 {
27233 }
27236 }
27237 else
27238 {
27241 {
27242 instantiation
27248 }
27252 }
27255 {
27256 /* If INSTANTIATION has been instantiated, then we don't
27257 need to consider it again in the future. */
27262 }
27263 else
27264 {
27267 }
27270 }
27272 }
27276 }
27278 /* Substitute ARGVEC into T, which is a list of initializers for
27279 either base class or a non-static data member. The TREE_PURPOSEs
27280 are DECLs, and the TREE_VALUEs are the initializer values. Used by
27281 instantiate_decl. */
27283 static tree
27285 {
27290 {
27291 tree decl;
27292 tree init;
27298 {
27299 tree expr;
27300 tree arg;
27302 /* Expand the base class expansion type into separate base
27303 classes. */
27305 tf_warning_or_error,
27306 NULL_TREE);
27310 /* We'll be building separate TREE_LISTs of arguments for
27311 each base. */
27317 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
27318 expand each argument in the TREE_VALUE of t. */
27325 /* VOID_TYPE_NODE is used to indicate
27326 value-initialization. */
27327 {
27330 }
27331 else
27332 {
27333 /* Substitute parameter packs into each argument in the
27334 TREE_LIST. */
27337 {
27338 tree expanded_exprs;
27340 /* Expand the argument. */
27341 tree value;
27344 else
27345 {
27348 }
27349 expanded_exprs
27351 tf_warning_or_error,
27352 NULL_TREE);
27356 /* Prepend each of the expanded expressions to the
27357 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
27365 else
27370 }
27373 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
27374 since we built them backwards. */
27376 {
27379 }
27380 }
27381 }
27384 {
27386 {
27390 }
27391 else
27392 {
27393 tree tmp;
27407 /* If we had an initializer but it instantiated to nothing,
27408 value-initialize the object. This will only occur when
27409 the initializer was a pack expansion where the parameter
27410 packs used in that expansion were of length zero. */
27413 }
27417 {
27419 decl);
27421 }
27422 /* Look for a target constructor. */
27426 {
27429 {
27433 }
27435 }
27438 {
27440 /* Carry over the dummy TREE_TYPE node containing the source
27441 location. */
27445 }
27446 }
27447 }
27449 }
27451 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
27452 is the instantiation (which should have been created with
27453 start_enum) and ARGS are the template arguments to use. */
27455 static void
27457 {
27458 tree e;
27464 {
27465 tree value;
27468 /* Note that in a template enum, the TREE_VALUE is the
27469 CONST_DECL, not the corresponding INTEGER_CST. */
27473 /* Give this enumeration constant the correct access. */
27476 /* Actually build the enumerator itself. Here we're assuming that
27477 enumerators can't have dependent attributes. */
27481 /* Attribute deprecated without an argument isn't sticky: it'll
27482 melt into a tree flag, so we need to propagate the flag here,
27483 since we just created a new enumerator. */
27486 }
27498 }
27500 /* DECL is a FUNCTION_DECL that is a template specialization. Return
27501 its type -- but without substituting the innermost set of template
27502 arguments. So, innermost set of template parameters will appear in
27503 the type. */
27505 tree
27507 {
27508 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
27510 }
27512 /* Return truthvalue if we're processing a template different from
27513 the last one involved in diagnostics. */
27514 bool
27516 {
27518 }
27520 /* Remember current template involved in diagnostics. */
27521 void
27523 {
27525 }
27529 {
27531 }
27533 /* Return TRUE if current_function_decl is being instantiated, false
27534 otherwise. */
27536 bool
27538 {
27542 }
27544 /* [temp.param] Check that template non-type parm TYPE is of an allowable
27545 type. Return false for ok, true for disallowed. Issue error and
27546 inform messages under control of COMPLAIN. */
27548 static bool
27550 {
27561 {
27563 {
27568 }
27570 }
27575 /* Fall through; before C++11 alias templates, a bound ttp
27578 /* Any other wildcard type not already handled above is allowed. */
27585 {
27593 {
27594 auto_diagnostic_group d;
27598 }
27600 }
27602 {
27607 }
27610 {
27613 else
27615 type);
27616 }
27618 }
27620 /* Returns true iff the noexcept-specifier for TYPE is value-dependent. */
27622 static bool
27624 {
27627 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
27628 affect overload resolution and treating it as dependent breaks
27629 things. Same for an unparsed noexcept expression. */
27636 }
27638 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
27639 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
27641 static bool
27643 {
27644 tree scope;
27646 /* [temp.dep.type]
27648 A type is dependent if it is:
27650 -- a template parameter. Template template parameters are types
27651 for us (since TYPE_P holds true for them) so we handle
27652 them here. */
27656 /* -- a qualified-id with a nested-name-specifier which contains a
27657 class-name that names a dependent type or whose unqualified-id
27658 names a dependent type. */
27662 /* An alias template specialization can be dependent even if the
27663 resulting type is not. */
27667 /* -- a cv-qualified type where the cv-unqualified type is
27668 dependent.
27669 No code is necessary for this bullet; the code below handles
27670 cv-qualified types, and we don't want to strip aliases with
27671 TYPE_MAIN_VARIANT because of DR 1558. */
27672 /* -- a compound type constructed from any dependent type. */
27680 {
27681 tree arg_type;
27686 arg_type;
27692 /* A value-dependent noexcept-specifier makes the type dependent. */
27695 }
27696 /* -- an array type constructed from any dependent type or whose
27697 size is specified by a constant expression that is
27698 value-dependent.
27700 We checked for type- and value-dependence of the bounds in
27701 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
27703 {
27708 }
27710 /* -- a template-id in which either the template name is a template
27711 parameter ... */
27714 /* ... or any of the template arguments is a dependent type or
27715 an expression that is type-dependent or value-dependent. */
27717 && (any_dependent_template_arguments_p
27721 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and TRAIT_TYPEs are
27722 dependent; if the argument of the `typeof' expression is not
27723 type-dependent, then it should already been have resolved. */
27729 /* A template argument pack is dependent if any of its packed
27730 arguments are. */
27732 {
27737 }
27739 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
27740 be template parameters. */
27750 /* The standard does not specifically mention types that are local
27751 to template functions or local classes, but they should be
27752 considered dependent too. For example:
27754 template <int I> void f() {
27755 enum E { a = I };
27756 S<sizeof (E)> s;
27757 }
27759 The size of `E' cannot be known until the value of `I' has been
27760 determined. Therefore, `E' must be considered dependent. */
27764 /* Don't use type_dependent_expression_p here, as it can lead
27765 to infinite recursion trying to determine whether a lambda
27766 nested in a lambda is dependent (c++/47687). */
27770 && (any_dependent_template_arguments_p
27774 /* Other types are non-dependent. */
27776 }
27778 /* Returns TRUE if TYPE is dependent, in the sense of
27779 [temp.dep.type]. Note that a NULL type is considered dependent. */
27781 bool
27783 {
27784 /* If there are no template parameters in scope, then there can't be
27785 any dependent types. */
27787 {
27788 /* If we are not processing a template, then nobody should be
27789 providing us with a dependent type. */
27793 }
27795 /* If the type is NULL, we have not computed a type for the entity
27796 in question; in that case, the type is dependent. */
27800 /* Erroneous types can be considered non-dependent. */
27804 /* If we have not already computed the appropriate value for TYPE,
27805 do so now. */
27807 {
27810 }
27813 }
27815 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
27816 lookup. In other words, a dependent type that is not the current
27817 instantiation. */
27819 bool
27821 {
27824 }
27826 /* True if we might find more declarations in SCOPE during instantiation than
27827 we can when parsing the template. */
27829 bool
27831 {
27833 }
27835 /* T is a SCOPE_REF. Return whether it represents a non-static member of
27836 an unknown base of 'this' (and is therefore instantiation-dependent). */
27838 static bool
27840 {
27857 }
27859 /* T is a SCOPE_REF; return whether we need to consider it
27860 instantiation-dependent so that we can check access at instantiation
27861 time even though we know which member it resolves to. */
27863 static bool
27865 {
27873 else
27875 }
27877 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
27878 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
27879 expression. */
27881 /* Note that this predicate is not appropriate for general expressions;
27882 only constant expressions (that satisfy potential_constant_expression)
27883 can be tested for value dependence. */
27885 bool
27887 {
27891 /* A type-dependent expression is also value-dependent. */
27896 {
27898 /* A dependent member function of the current instantiation. */
27902 /* A dependent member function of the current instantiation. */
27909 /* A name that has not been looked up -- must be dependent. */
27913 /* A non-type template parm. */
27917 /* A non-type template parm. */
27923 /* A constant with literal type and is initialized
27924 with an expression that is value-dependent. */
27928 {
27931 /* __PRETTY_FUNCTION__ inside a template function is dependent
27932 on the name of the function. */
27934 /* It might be used in a template, but not a template
27935 function, in which case its DECL_VALUE_EXPR will be
27936 "top level". */
27939 }
27941 /* FIXME cp_finish_decl doesn't fold reference initializers. */
27951 /* These expressions are value-dependent if the type to which
27952 the cast occurs is dependent or the expression being casted
27953 is value-dependent. */
27954 {
27960 /* A functional cast has a list of operands. */
27963 {
27964 /* If there are no operands, it must be an expression such
27965 as "int()". This should not happen for aggregate types
27966 because it would form non-constant expressions. */
27971 }
27981 }
27986 /* FALLTHRU */
27989 /* A `sizeof' expression is value-dependent if the operand is
27990 type-dependent or is a pack expansion. */
27999 /* An 'encode' expression is value-dependent if the operand is
28000 type-dependent. */
28009 /* All instantiation-dependent expressions should also be considered
28010 value-dependent. */
28018 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
28019 is value-dependent. */
28026 {
28042 }
28053 {
28057 }
28060 /* Treat all requires-expressions as value-dependent so
28061 we don't try to fold them. */
28068 {
28075 {
28077 /* In a call to a constexpr member function, look through the
28078 implicit ADDR_EXPR on the object argument so that it doesn't
28079 cause the call to be considered value-dependent. We also
28080 look through it in potential_constant_expression. */
28087 }
28089 }
28096 {
28098 tree val;
28105 }
28108 /* Treat a GNU statement expression as dependent to avoid crashing
28109 under instantiate_non_dependent_expr; it can't be constant. */
28114 /* The second operand is a type, which type_dependent_expression_p
28115 (and therefore value_dependent_expression_p) doesn't want to see. */
28121 /* A constant expression is value-dependent if any subexpression is
28122 value-dependent. */
28124 {
28131 {
28135 {
28138 /* In some cases, some of the operands may be missing.
28139 (For example, in the case of PREDECREMENT_EXPR, the
28140 amount to increment by may be missing.) That doesn't
28141 make the expression dependent. */
28144 }
28145 }
28149 }
28151 }
28153 /* The expression is not value-dependent. */
28155 }
28157 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
28158 [temp.dep.expr]. Note that an expression with no type is
28159 considered dependent. Other parts of the compiler arrange for an
28160 expression with type-dependent subexpressions to have no type, so
28161 this function doesn't have to be fully recursive. */
28163 bool
28165 {
28176 /* An unresolved name is always dependent. */
28182 /* A lambda-expression in template context is dependent. dependent_type_p is
28183 true for a lambda in the scope of a class or function template, but that
28184 doesn't cover all template contexts, like a default template argument. */
28188 /* A fold expression is type-dependent. */
28195 /* Some expression forms are never type-dependent. */
28208 /* The types of these expressions depends only on the type to which
28209 the cast occurs. */
28218 /* The types of these expressions depends only on the type created
28219 by the expression. */
28222 {
28223 /* For NEW_EXPR tree nodes created inside a template, either
28224 the object type itself or a TREE_LIST may appear as the
28225 operand 1. */
28228 /* This is an array type. We need to check array dimensions
28229 as well. */
28231 || value_dependent_expression_p
28233 /* Array type whose dimension has to be deduced. */
28237 else
28239 }
28242 {
28246 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
28247 contains an identifier associated by name lookup with one or more
28248 declarations declared with a dependent type, or...a
28249 nested-name-specifier or qualified-id that names a member of an
28250 unknown specialization. */
28253 }
28263 {
28268 }
28270 /* A static data member of the current instantiation with incomplete
28271 array type is type-dependent, as the definition and specializations
28272 can have different bounds. */
28279 /* An array of unknown bound depending on a variadic parameter, eg:
28281 template<typename... Args>
28282 void foo (Args... args)
28283 {
28284 int arr[] = { args... };
28285 }
28287 template<int... vals>
28288 void bar ()
28289 {
28290 int arr[] = { vals... };
28291 }
28293 If the array has no length and has an initializer, it must be that
28294 we couldn't determine its length in cp_complete_array_type because
28295 it is dependent. */
28303 /* Pull a FUNCTION_DECL out of a BASELINK if we can. */
28305 {
28310 }
28312 /* A function or variable template-id is type-dependent if it has any
28313 dependent template arguments. */
28317 {
28318 /* Consider the innermost template arguments, since those are the ones
28319 that come from the template-id; the template arguments for the
28320 enclosing class do not make it type-dependent unless they are used in
28321 the type of the decl. */
28323 && (any_dependent_template_arguments_p
28326 }
28328 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
28329 type-dependent. Checking this is important for functions with auto return
28330 type, which looks like a dependent type. */
28339 {
28343 }
28345 /* Otherwise, its constraints could still depend on outer template parameters
28346 from its (dependent) scope. */
28348 /* As an optimization, check this cheaper sufficient condition first.
28349 (At this point we've established that we're looking at a member of
28350 a dependent class, so it makes sense to start treating say undeduced
28351 auto as dependent.) */
28356 /* Always dependent, on the number of arguments if nothing else. */
28361 {
28366 {
28372 }
28373 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
28377 /* CO_AWAIT/YIELD_EXPR with unknown type is always dependent. */
28383 {
28388 }
28391 {
28398 }
28407 }
28409 /* The type of a non-type template parm declared with a placeholder type
28410 depends on the corresponding template argument, even though
28411 placeholders are not normally considered dependent. */
28418 /* Dependent type attributes might not have made it from the decl to
28419 the type yet. */
28425 }
28427 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
28428 type-dependent if the expression refers to a member of the current
28429 instantiation and the type of the referenced member is dependent, or the
28430 class member access expression refers to a member of an unknown
28431 specialization.
28433 This function returns true if the OBJECT in such a class member access
28434 expression is of an unknown specialization. */
28436 bool
28438 {
28439 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
28440 dependent. */
28445 }
28447 /* walk_tree callback function for instantiation_dependent_expression_p,
28448 below. Returns non-zero if a dependent subexpression is found. */
28450 static tree
28453 {
28455 {
28456 /* We don't have to worry about decltype currently because decltype
28457 of an instantiation-dependent expr is a dependent type. This
28458 might change depending on the resolution of DR 1172. */
28461 }
28464 {
28465 /* Don't treat an argument list as dependent just because it has no
28466 TREE_TYPE. */
28477 /* We'll check value-dependence separately. */
28480 /* Handle expressions with type operands. */
28485 {
28490 {
28493 else
28494 {
28497 }
28498 }
28500 }
28504 /* In a template, finish_class_member_access_expr creates a
28505 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
28506 type-dependent, so that we can check access control at
28507 instantiation time (PR 42277). See also Core issue 1273. */
28514 else
28517 /* Treat statement-expressions as dependent. */
28521 /* Treat requires-expressions as dependent. */
28532 /* Before C++17, a noexcept-specifier isn't part of the function type
28533 so it doesn't affect type dependence, but we still want to consider it
28534 for instantiation dependence. */
28543 }
28547 else
28549 }
28551 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
28552 sense defined by the ABI:
28554 "An expression is instantiation-dependent if it is type-dependent
28555 or value-dependent, or it has a subexpression that is type-dependent
28556 or value-dependent."
28558 Except don't actually check value-dependence for unevaluated expressions,
28559 because in sizeof(i) we don't care about the value of i. Checking
28560 type-dependence will in turn check value-dependence of array bounds/template
28561 arguments as needed. */
28563 bool
28565 {
28566 tree result;
28577 }
28579 /* As above, but also check value-dependence of the expression as a whole. */
28581 bool
28583 {
28585 || (processing_template_decl
28588 }
28590 /* Like type_dependent_expression_p, but it also works while not processing
28591 a template definition, i.e. during substitution or mangling. */
28593 bool
28595 {
28601 }
28603 /* Returns TRUE if ARGS contains a type-dependent expression. */
28605 bool
28607 {
28616 }
28618 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
28619 expressions) contains any type-dependent expressions. */
28621 bool
28623 {
28629 }
28631 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
28632 expressions) contains any value-dependent expressions. */
28634 bool
28636 {
28642 }
28644 /* Returns TRUE if the ARG (a template argument) is dependent. */
28646 bool
28648 {
28652 /* Assume a template argument that was wrongly written by the user
28653 is dependent. This is consistent with what
28654 any_dependent_template_arguments_p [that calls this function]
28655 does. */
28665 {
28668 /* A member template of a dependent class is not necessarily
28669 type-dependent, but it is a dependent template argument because it
28670 will be a member of an unknown specialization to that template. */
28673 }
28675 {
28681 }
28684 else
28686 }
28688 /* Identify any expressions that use function parms. */
28690 static tree
28692 {
28695 {
28698 }
28700 }
28702 /* Returns true if a type specialization formed using the template
28703 arguments ARGS needs to use structural equality. */
28705 bool
28707 {
28717 {
28720 {
28726 {
28727 /* Look inside the argument pack. */
28730 }
28733 {
28742 /* An any_targ_node argument (added by add_defaults_to_ttp)
28743 makes the corresponding specialization not canonicalizable,
28744 since template_args_equal always return true for it. We
28745 may see this when called from bind_template_template_parm. */
28747 /* Checking current_function_decl because this structural
28748 comparison is only necessary for redeclaration. */
28751 && (cp_walk_tree_without_duplicates
28753 /* The identity of a class template specialization that uses
28754 a function parameter depends on the identity of the function.
28755 And if this specialization appeared in the trailing return
28756 type thereof, we don't know the identity of the function
28757 (e.g. if it's a redeclaration or a new function) until we
28758 form its signature and go through duplicate_decls. Thus
28759 it's unsafe to decide on a canonical type now (which depends
28760 on the DECL_CONTEXT of the function parameter, which can get
28761 mutated after the fact by duplicate_decls), so just require
28762 structural equality in this case (PR52830). */
28764 }
28765 }
28766 }
28769 }
28771 /* Returns true if ARGS (a collection of template arguments) contains
28772 any dependent arguments. */
28774 bool
28776 {
28783 {
28788 }
28791 }
28793 /* Returns true if ARGS contains any errors. */
28795 bool
28797 {
28805 {
28808 else
28810 }
28816 {
28821 }
28824 }
28826 /* Returns TRUE if the template TMPL is type-dependent. */
28828 bool
28830 {
28832 {
28837 }
28839 /* Template template parameters are dependent. */
28843 /* So are names that have not been looked up. */
28847 }
28849 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
28851 bool
28853 {
28856 }
28858 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
28859 are dependent. */
28861 bool
28863 {
28870 {
28895 {
28899 }
28903 {
28907 {
28913 /* If this loop has a class iterator with != comparison
28914 with increment other than i++/++i/i--/--i, make sure the
28915 increment is constant. */
28918 {
28921 else
28925 }
28926 }
28927 }
28928 }
28931 }
28933 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
28934 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
28935 no such TYPE can be found. Note that this function peers inside
28936 uninstantiated templates and therefore should be used only in
28937 extremely limited situations. ONLY_CURRENT_P restricts this
28938 peering to the currently open classes hierarchy (which is required
28939 when comparing types). */
28941 tree
28943 {
28944 tree scope;
28945 tree name;
28946 tree decl;
28948 tree pushed_scope;
28949 tree result;
28954 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
28957 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
28958 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of a
28959 TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL
28960 representing the typedef. In that case TYPE_IDENTIFIER (type) is
28961 not the non-qualified identifier of the TYPENAME_TYPE anymore.
28962 So by getting the TYPE_IDENTIFIER of the _main declaration_ of
28963 the TYPENAME_TYPE instead, we avoid messing up with a possible
28964 typedef variant case. */
28967 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
28968 it first before we can figure out what NAME refers to. */
28970 {
28972 /* Given a class template A with a dependent base with nested type C,
28973 typedef typename A::C::C C will land us here, as trying to resolve
28974 the initial A::C leads to the local C typedef, which leads back to
28975 A::C::C. So we break the recursion now. */
28977 else
28979 }
28980 /* If we don't know what SCOPE refers to, then we cannot resolve the
28981 TYPENAME_TYPE. */
28984 /* If this is a typedef, we don't want to look inside (c++/11987). */
28987 /* If SCOPE isn't the template itself, it will not have a valid
28988 TYPE_FIELDS list. */
28990 /* scope is either the template itself or a compatible instantiation
28991 like X<T>, so look up the name in the original template. */
28993 /* If scope has no fields, it can't be a current instantiation. Check this
28994 before currently_open_class to avoid infinite recursion (71515). */
28997 /* If the SCOPE is not the current instantiation, there's no reason
28998 to look inside it. */
29001 /* Enter the SCOPE so that name lookup will be resolved as if we
29002 were in the class definition. In particular, SCOPE will no
29003 longer be considered a dependent type. */
29005 /* Look up the declaration. */
29007 tf_warning_or_error);
29011 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
29012 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
29018 {
29022 }
29025 {
29026 /* Obtain the template and the arguments. */
29029 {
29030 /* We get here with a plain identifier because a previous tentative
29031 parse of the nested-name-specifier as part of a ptr-operator saw
29032 ::template X<A>. The use of ::template is necessary in a
29033 ptr-operator, but wrong in a declarator-id.
29035 [temp.names]: In a qualified-id of a declarator-id, the keyword
29036 template shall not appear at the top level. */
29040 }
29042 /* Instantiate the template. */
29048 }
29050 /* Leave the SCOPE. */
29054 /* If we failed to resolve it, return the original typename. */
29058 /* If lookup found a typename type, resolve that too. */
29060 {
29061 /* Ill-formed programs can cause infinite recursion here, so we
29062 must catch that. */
29066 }
29068 /* Qualify the resulting type. */
29074 }
29076 /* EXPR is an expression which is not type-dependent. Return a proxy
29077 for EXPR that can be used to compute the types of larger
29078 expressions containing EXPR. */
29080 tree
29082 {
29084 tree inner_expr;
29086 /* When checking, try to get a constant value for all non-dependent
29087 expressions in order to expose bugs in *_dependent_expression_p
29088 and constexpr. This can affect code generation, see PR70704, so
29089 only do this for -fchecking=2. */
29092 /* Don't do this during nsdmi parsing as it can lead to
29093 unexpected recursive instantiations. */
29095 /* Don't do this during concept processing either and for
29096 the same reason. */
29102 /* Preserve OVERLOADs; the functions must be available to resolve
29103 types. */
29114 /* There is no need to return a proxy for a variable, parameter
29115 or enumerator. */
29119 /* Preserve string constants; conversions from string constants to
29120 "char *" are allowed, even though normally a "const char *"
29121 cannot be used to initialize a "char *". */
29124 /* Preserve void and arithmetic constants, as an optimization -- there is no
29125 reason to create a new node. */
29130 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
29131 There is at least one place where we want to know that a
29132 particular expression is a throw-expression: when checking a ?:
29133 expression, there are special rules if the second or third
29134 argument is a throw-expression. */
29138 /* Don't wrap an initializer list, we need to be able to look inside. */
29142 /* Don't wrap a dummy object, we need to be able to test for it. */
29160 /* If the type is unknown, it can't really be non-dependent */
29163 /* Otherwise, build a NON_DEPENDENT_EXPR. */
29166 }
29168 /* ARGS is a vector of expressions as arguments to a function call.
29169 Replace the arguments with equivalent non-dependent expressions.
29170 This modifies ARGS in place. */
29172 void
29174 {
29176 tree arg;
29179 {
29183 }
29184 }
29186 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
29187 TEMPLATE_TYPE_PARM with a level one deeper than the actual template parms,
29188 by default. If set_canonical is true, we set TYPE_CANONICAL on it. */
29190 static tree
29192 {
29208 }
29210 tree
29212 {
29214 }
29216 tree
29218 {
29220 }
29222 /* Return a C++17 deduction placeholder for class template TMPL.
29223 There are represented as an 'auto' with the special level 0 and
29224 CLASS_PLACEHOLDER_TEMPLATE set. */
29226 tree
29228 {
29231 /* Our canonical type depends on the placeholder. */
29234 }
29236 /* True iff T is a C++17 class template deduction placeholder. */
29238 bool
29240 {
29242 }
29244 /* Make a "constrained auto" type-specifier. This is an auto or
29245 decltype(auto) type with constraints that must be associated after
29246 deduction. The constraint is formed from the given concept CON
29247 and its optional sequence of template arguments ARGS.
29249 TYPE must be the result of make_auto_type or make_decltype_auto_type. */
29251 static tree
29253 {
29254 /* Build the constraint. */
29266 /* Our canonical type depends on the constraint. */
29269 /* Attach the constraint to the type declaration. */
29271 }
29273 /* Make a "constrained auto" type-specifier. */
29275 tree
29277 {
29280 }
29282 /* Make a "constrained decltype(auto)" type-specifier. */
29284 tree
29286 {
29289 }
29291 /* Returns true if the placeholder type constraint T has any dependent
29292 (explicit) template arguments. */
29294 static bool
29296 {
29301 {
29304 }
29311 }
29313 /* Build and return a concept definition. Like other templates, the
29314 CONCEPT_DECL node is wrapped by a TEMPLATE_DECL. This returns the
29315 the TEMPLATE_DECL. */
29317 tree
29319 {
29325 /* A concept-definition shall not have associated constraints. */
29327 {
29330 }
29332 /* A concept-definition shall appear in namespace scope. Templates
29333 aren't allowed in block scope, so we only need to check for class
29334 scope. */
29336 {
29339 }
29342 {
29345 }
29347 /* Initially build the concept declaration; its type is bool. */
29357 /* Push the enclosing template. */
29359 }
29361 /* Given type ARG, return std::initializer_list<ARG>. */
29363 static tree
29365 {
29370 {
29374 "deducing from brace-enclosed initializer list"
29378 }
29384 }
29386 /* Replace auto in TYPE with std::initializer_list<auto>. */
29388 static tree
29390 {
29397 }
29399 /* Hash traits for hashing possibly constrained 'auto'
29400 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
29403 {
29406 };
29408 /* Hash the 'auto' T. */
29410 inline hashval_t
29412 {
29414 /* Matching constrained-type-specifiers denote the same template
29415 parameter, so hash the constraint. */
29417 else
29418 /* But unconstrained autos are all separate, so just hash the pointer. */
29420 }
29422 /* Compare two 'auto's. */
29426 {
29433 /* Two unconstrained autos are distinct. */
29438 }
29440 /* for_each_template_parm callback for extract_autos: if t is a (possibly
29441 constrained) auto, add it to the vector. */
29443 static int
29445 {
29448 {
29449 /* All the autos were built with index 0; fix that up now. */
29453 /* If this is a repeated constrained-type-specifier, use the index we
29454 chose before. */
29456 else
29457 {
29458 /* Otherwise this is new, so use the current count. */
29461 }
29463 {
29468 }
29469 }
29471 /* Always keep walking. */
29473 }
29475 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
29476 says they can appear anywhere in the type. */
29478 static tree
29480 {
29488 {
29492 }
29495 }
29497 /* The stem for deduction guide names. */
29500 /* Return the name for a deduction guide for class template TMPL. */
29502 tree
29504 {
29515 }
29517 /* True if NAME is the name of a deduction guide. */
29519 bool
29521 {
29525 }
29527 /* True if FN is a deduction guide. */
29529 bool
29531 {
29536 }
29538 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
29540 bool
29542 {
29549 }
29551 /* True if FN is a guide generated from a constructor template. */
29553 bool
29555 {
29563 }
29565 /* True if FN is an aggregate initialization guide or the copy deduction
29566 guide. */
29568 bool
29570 {
29574 /* Explicitly declared. */
29577 /* Derived from a constructor. */
29580 }
29582 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
29583 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
29584 template parameter types. Note that the handling of template template
29585 parameters relies on current_template_parms being set appropriately for the
29586 new template. */
29588 static tree
29591 {
29597 tree newtype;
29600 {
29604 }
29605 else
29606 {
29609 {
29610 // Substitute once to fix references to other template parameters.
29613 // Now substitute again to reduce the level of the auto.
29616 }
29617 else
29620 }
29622 tree newdecl
29627 tree newidx;
29630 {
29639 {
29644 // First create a copy (ttargs) of tsubst_args with an
29645 // additional level for the template template parameter's own
29646 // template parameters (ttparms).
29647 tree ttparms = (INNERMOST_TEMPLATE_PARMS
29655 // Substitute ttargs into ttparms to fix references to
29656 // other template parameters.
29659 // Now substitute again with args based on tparms, to reduce
29660 // the level of the ttparms.
29663 complain);
29664 // Finally, tack the adjusted parms onto tparms.
29667 // As with all template template parms, the parameter list captured
29668 // by this template template parm that corresponds to its own level
29669 // should be empty. This avoids infinite recursion when structurally
29670 // comparing two such rewritten template template parms (PR102479).
29675 // All done.
29677 }
29681 else
29683 }
29684 else
29685 {
29687 tree newconst
29699 }
29702 }
29704 /* As rewrite_template_parm, but for the whole TREE_LIST representing a
29705 template parameter. */
29707 static tree
29710 {
29725 }
29727 /* Returns a C++17 class deduction guide template based on the constructor
29728 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
29729 guide, REFERENCE_TYPE for an implicit copy/move guide, or TREE_LIST for an
29730 aggregate initialization guide. OUTER_ARGS are the template arguments
29731 for the enclosing scope of the class. */
29733 static tree
29735 {
29739 location_t loc;
29743 {
29747 }
29750 {
29752 {
29756 else
29758 }
29761 else
29771 }
29772 else
29773 {
29779 fn_tmpl
29787 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
29788 fully specialized args for the enclosing class. Strip those off, as
29789 the deduction guide won't have those template parameters. */
29792 /* Discard the 'this' parameter. */
29800 {
29803 /* For a member template constructor, we need to flatten the two
29804 template parameter lists into one, and then adjust the function
29805 signature accordingly. This gets...complicated. */
29808 /* For a member template we should have two levels of parms/args, one
29809 for the class and one for the constructor. We stripped
29810 specialized args for further enclosing classes above. */
29814 /* Template args for translating references to the two-level template
29815 parameters into references to the one-level template parameters we
29816 are creating. */
29821 /* Template parms for the constructor template. */
29824 /* Template parms for the class template. */
29828 /* Template parms for the deduction guide start as a copy of the
29829 template parms for the class. We set current_template_parms for
29830 lookup_template_class_1. */
29836 /* Now we need to rewrite the constructor parms to append them to the
29837 class parms. */
29839 {
29843 tree newelt
29849 }
29851 /* Now we have a final set of template parms to substitute into the
29852 function signature. */
29859 {
29861 /* FIXME: We'd like to avoid substituting outer template
29862 arguments into the constraint ahead of time, but the
29863 construction of tsubst_args assumes that outer arguments
29864 are already substituted in. */
29867 }
29869 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped if
29870 cp_unevaluated_operand. */
29871 cp_evaluated ev;
29874 }
29875 else
29876 {
29877 /* Substitute in the same arguments to rewrite class members into
29878 references to members of an unknown specialization. */
29879 cp_evaluated ev;
29883 {
29885 /* FIXME: As above. */
29888 }
29889 }
29894 }
29897 {
29898 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
29902 }
29906 FUNCTION_DECL,
29921 }
29923 /* Add to LIST the member types for the reshaped initializer CTOR. */
29925 static tree
29927 {
29931 {
29935 {
29941 }
29945 /* Give the trailing pack expansion parameter a default argument to
29946 match aggregate initialization behavior, even if we deduce the
29947 length of the pack separately to more than we have initializers. */
29949 /* if ei is of array type and xi is a braced-init-list or string literal,
29950 Ti is an rvalue reference to the declared type of ei */
29955 {
29957 ftype = cp_build_qualified_type
29959 ftype = (cp_build_reference_type
29961 }
29963 }
29966 }
29968 /* Return whether ETYPE is, or is derived from, a specialization of TMPL. */
29970 static bool
29972 {
29978 tree tparms = (INNERMOST_TEMPLATE_PARMS
29985 }
29989 /* Return a C++20 aggregate deduction candidate for TYPE initialized from
29990 INIT. */
29992 static tree
29994 {
30002 {
30008 }
30010 /* We might be creating a guide for a class member template, e.g.,
30012 template<typename U> struct A {
30013 template<typename T> struct B { T t; };
30014 };
30016 At this point, A will have been instantiated. Below, we need to
30017 use both A<U>::B<T> (TEMPLATE_TYPE) and A<int>::B<T> (TYPE) types. */
30018 const bool member_template_p
30022 tree template_type = (member_template_p
30028 /* No aggregate candidate for copy-initialization. */
30030 {
30034 }
30036 /* If we encounter a problem, we just won't add the candidate. */
30041 {
30046 /* If we're creating a deduction guide for a member class template,
30047 we've used the original template pattern type for the reshape_init
30048 above; this is done because we want PARMS to be a template parameter
30049 type, something that can be deduced when used as a function template
30050 parameter. At this point the outer class template has already been
30051 partially instantiated (we deferred the deduction until the enclosing
30052 scope is non-dependent). Therefore we have to partially instantiate
30053 PARMS, so that its template level is properly reduced and we don't get
30054 mismatches when deducing types using the guide with PARMS. */
30056 {
30060 }
30061 }
30063 {
30066 len;
30068 {
30074 }
30075 }
30076 else
30077 /* Aggregate initialization doesn't apply to an initializer expression. */
30081 {
30087 }
30090 }
30092 /* UGUIDES are the deduction guides for the underlying template of alias
30093 template TMPL; adjust them to be deduction guides for TMPL. */
30095 static tree
30097 {
30098 /* [over.match.class.deduct]: When resolving a placeholder for a deduced
30099 class type (9.2.8.2) where the template-name names an alias template A,
30100 the defining-type-id of A must be of the form
30102 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
30104 as specified in 9.2.8.2. The guides of A are the set of functions or
30105 function templates formed as follows. For each function or function
30106 template f in the guides of the template named by the simple-template-id
30107 of the defining-type-id, the template arguments of the return type of f
30108 are deduced from the defining-type-id of A according to the process in
30109 13.10.2.5 with the exception that deduction does not fail if not all
30110 template arguments are deduced. Let g denote the result of substituting
30111 these deductions into f. If substitution succeeds, form a function or
30112 function template f' with the following properties and add it to the set
30113 of guides of A:
30115 * The function type of f' is the function type of g.
30117 * If f is a function template, f' is a function template whose template
30118 parameter list consists of all the template parameters of A (including
30119 their default template arguments) that appear in the above deductions or
30120 (recursively) in their default template arguments, followed by the
30121 template parameters of f that were not deduced (including their default
30122 template arguments), otherwise f' is not a function template.
30124 * The associated constraints (13.5.2) are the conjunction of the
30125 associated constraints of g and a constraint that is satisfied if and only
30126 if the arguments of A are deducible (see below) from the return type.
30128 * If f is a copy deduction candidate (12.4.1.8), then f' is considered to
30129 be so as well.
30131 * If f was generated from a deduction-guide (12.4.1.8), then f' is
30132 considered to be so as well.
30134 * The explicit-specifier of f' is the explicit-specifier of g (if
30135 any). */
30145 {
30152 {
30156 /* Deduce template arguments for f from the type-id of A. */
30162 /* CWG2664: Discard any deductions, still build the guide. */
30166 /* The number of parms for f' is the number of parms of A used in
30167 the deduced arguments plus non-deduced parms of f. */
30179 /* Set current_template_parms as in build_deduction_guide. */
30187 /* First copy over the used parms of A. */
30190 {
30193 {
30198 }
30199 }
30202 /* Adjust the deduced template args for f to refer to the A parms
30203 with their new indexes. */
30207 /* Now rewrite the non-deduced parms of f. */
30210 {
30217 }
30220 /* Substitute the deduced arguments plus the rewritten template
30221 parameters into f to get g. This covers the type, copyness,
30222 guideness, and explicit-specifier. */
30223 tree g;
30224 {
30225 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped
30226 if cp_unevaluated_operand. */
30227 cp_evaluated ev;
30229 }
30233 {
30234 /* The targs are all non-dependent, so g isn't a template. */
30238 }
30247 /* Substitute the associated constraints. */
30254 /* Add a constraint that the return type matches the instantiation of
30255 A with the same template arguments. */
30258 /* FIXME this should mean they don't compare as equivalent. */
30260 {
30263 }
30266 {
30269 }
30270 }
30271 else
30272 {
30273 /* For a non-template deduction guide, if the arguments of A aren't
30274 deducible from the return type, don't add the candidate. */
30275 non_template:
30278 }
30281 }
30284 }
30286 /* True iff template arguments for TMPL can be deduced from TYPE.
30287 Used to implement CPTK_IS_DEDUCIBLE for alias CTAD according to
30288 [over.match.class.deduct].
30290 This check is specified in terms of partial specialization, so the behavior
30291 should be parallel to that of get_partial_spec_bindings. */
30293 bool
30295 {
30301 /* If tmpl is a class template, this is trivial: it's deducible if TYPE is a
30302 specialization of TMPL. */
30308 /* Otherwise it's an alias template. */
30309 again:
30314 /* We don't fail on an undeduced targ the second time through (like
30315 get_partial_spec_bindings) because we're going to try defaults. */
30318 {
30324 {
30329 }
30330 /* If the type parameter is a parameter pack, then it will be deduced
30331 to an empty parameter pack. This is another case that doesn't model
30332 well as partial specialization. */
30334 {
30335 tree arg;
30337 {
30340 }
30341 else
30345 }
30346 }
30348 /* Maybe add in default template args. This seems like a flaw in the
30349 specification in terms of partial specialization, since it says the
30350 partial specialization has the the template parameter list of A, but a
30351 partial specialization can't have default targs. */
30356 /* I believe we don't need the template_template_parm_bindings_ok_p call
30357 because coerce_template_parms did coerce_template_template_parms. */
30360 }
30362 /* Return artificial deduction guides built from the constructors of class
30363 template TMPL. */
30365 static tree
30367 {
30374 {
30375 /* Skip inherited constructors. */
30381 }
30383 /* Add implicit default constructor deduction guide. */
30385 {
30387 complain);
30389 }
30391 /* Add copy guide. */
30392 {
30395 complain);
30397 }
30400 }
30404 /* Return the non-aggregate deduction guides for deducible template TMPL. The
30405 aggregate candidate is added separately because it depends on the
30406 initializer. Set ANY_DGUIDES_P if we find a non-implicit deduction
30407 guide. */
30409 static tree
30411 {
30414 {
30418 complain);
30419 }
30420 else
30421 {
30427 else
30429 }
30431 /* Cache the deduction guides for a template. We also remember the result of
30432 lookup, and rebuild everything if it changes; should be very rare. */
30436 {
30440 }
30441 else
30442 {
30445 }
30450 else
30451 {
30455 }
30459 }
30461 /* Return whether TMPL is a (class template argument-) deducible template. */
30463 bool
30465 {
30466 /* A deducible template is either a class template or is an alias template
30467 whose defining-type-id is of the form
30469 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
30471 where the nested-name-specifier (if any) is non-dependent and the
30472 template-name of the simple-template-id names a deducible template. */
30483 }
30485 /* Deduce template arguments for the class template placeholder PTYPE for
30486 template TMPL based on the initializer INIT, and return the resulting
30487 type. */
30489 static tree
30492 {
30493 /* We should have handled this in the caller. */
30497 /* If the class was erroneous, don't try to deduce, because that
30498 can generate a lot of diagnostic. */
30504 /* Wait until the enclosing scope is non-dependent. */
30509 /* Initializing one placeholder from another. */
30520 {
30524 }
30526 {
30528 {
30529 /* Be permissive with equivalent alias templates. */
30532 bool complained
30534 "alias template deduction only available "
30539 {
30542 }
30543 }
30544 else
30546 }
30548 /* Wait until the initializer is non-dependent. */
30552 /* Don't bother with the alias rules for an equivalent template. */
30565 {
30570 {
30571 /* As an exception, the first phase in 16.3.1.7 (considering the
30572 initializer list as a single argument) is omitted if the
30573 initializer list consists of a single expression of type cv U,
30574 where U is a specialization of C or a class derived from a
30575 specialization of C. */
30579 }
30582 else
30584 }
30587 else
30590 /* Do this now to avoid problems with erroneous args later on. */
30600 /* Prune explicit deduction guides in copy-initialization context (but
30601 not copy-list-initialization). */
30604 {
30610 {
30611 /* Found a nonconverting guide, prune the candidates. */
30618 }
30619 }
30627 /* If this is list-initialization and the class has a list guide, first
30628 try deducing from the list as a single argument, as [over.match.list]. */
30630 {
30638 {
30639 /* That didn't work, now try treating the list as a sequence of
30640 arguments. */
30646 }
30647 }
30650 {
30652 " of %qT, as it has no non-explicit deduction guides or "
30655 }
30657 {
30661 }
30667 {
30669 {
30675 }
30677 }
30678 /* [over.match.list]/1: In copy-list-initialization, if an explicit
30679 constructor is chosen, the initialization is ill-formed. */
30681 {
30683 {
30685 {
30686 // TODO: Pass down location from cp_finish_decl.
30688 "explicit deduction guide selected in "
30693 }
30695 }
30696 }
30698 /* If CTAD succeeded but the type doesn't have any explicit deduction
30699 guides, this deduction might not be what the user intended. */
30701 {
30705 "%qT may not intend to support class template argument "
30709 }
30713 }
30715 /* Return true if INIT is an unparenthesized id-expression or an
30716 unparenthesized class member access. Used for the argument of
30717 decltype(auto). */
30719 bool
30721 {
30724 /* We need to be able to tell '(r)' and 'r' apart (when it's of
30725 reference type). Only the latter is an id-expression. */
30733 }
30735 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
30736 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
30737 The CONTEXT determines the context in which auto deduction is performed
30738 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
30740 OUTER_TARGS is used during template argument deduction (context == adc_unify)
30741 to properly substitute the result. It's also used in the adc_unify and
30742 adc_requirement contexts to communicate the necessary template arguments
30743 to satisfaction. OUTER_TARGS is ignored in other contexts.
30745 Additionally for adc_unify contexts TMPL is the template for which TYPE
30746 is a template parameter type.
30748 For partial-concept-ids, extra args from OUTER_TARGS, TMPL and the current
30749 scope may be appended to the list of deduced template arguments prior to
30750 determining constraint satisfaction as appropriate. */
30752 tree
30759 {
30765 /* Defining a subset of type-dependent expressions that we can deduce
30766 from ahead of time isn't worth the trouble. */
30769 /* Similarly, we can't deduce from another undeduced decl. */
30773 /* We may be doing a partial substitution, but we still want to replace
30774 auto_node. */
30778 {
30779 /* We don't recurse here because we can't deduce from a nested
30780 initializer_list. */
30784 }
30788 /* In C++23, we must deduce the type to int&& for code like
30789 decltype(auto) f(int&& x) { return (x); }
30790 or
30791 auto&& f(int x) { return x; }
30792 so we use treat_lvalue_as_rvalue_p. But don't do it for
30793 decltype(auto) f(int x) { return x; }
30794 where we should deduce 'int' rather than 'int&&'; transmogrifying
30795 INIT to an rvalue would break that. */
30796 tree r;
30806 /* C++17 class template argument deduction. */
30810 /* Nothing we can do with this, even in deduction context. */
30815 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
30816 with either a new invented type template parameter U or, if the
30817 initializer is a braced-init-list (8.5.4), with
30818 std::initializer_list<U>. */
30820 {
30825 else
30826 {
30828 {
30832 "for deduction to %<std::initializer_list%>, use copy-"
30834 }
30836 }
30837 }
30842 tree targs;
30846 {
30847 /* [dcl.struct.bind]/1 - if decomposition declaration has no ref-qualifiers
30848 and initializer has array type, deduce cv-qualified array type. */
30851 }
30853 {
30861 }
30862 else
30863 {
30868 tree tparms;
30872 else
30873 {
30877 }
30881 DEDUCE_CALL,
30884 {
30886 /* Try again at instantiation time. */
30890 /* If type is error_mark_node a diagnostic must have been
30891 emitted by now. Also, having a mention to '<type error>'
30892 in the diagnostic is not really useful to the user. */
30893 {
30896 && (auto_node
30900 init);
30901 else
30904 DEDUCE_CALL,
30906 }
30908 }
30909 }
30911 /* Check any placeholder constraints against the deduced type. */
30915 {
30917 {
30922 /* If the constraint is dependent, we need to wait until
30923 instantiation time to resolve the placeholder. */
30926 }
30933 {
30937 {
30938 /* As in satisfy_declaration_constraints. */
30942 else
30944 }
30945 }
30952 /* HACK: Compensate for callers not always communicating all levels of
30953 outer template arguments by filling in the outermost missing levels
30954 with dummy levels before checking satisfaction. We'll still crash
30955 if the constraint depends on a template argument belonging to one of
30956 these missing levels, but this hack otherwise allows us to handle a
30957 large subset of possible constraints (including all non-dependent
30958 constraints). */
30961 {
30966 }
30969 {
30971 {
30972 auto_diagnostic_group d;
30974 {
30992 }
30994 }
30996 }
30997 }
31000 /* The outer template arguments are already substituted into type
31007 }
31009 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
31010 result. */
31012 tree
31014 {
31016 {
31019 }
31023 {
31024 /* In an abbreviated function template we didn't know we were dealing
31025 with a function template when we saw the auto return type, so rebuild
31026 the return type using an auto with the correct level. */
31031 auto_vec);
31032 /* Also rebuild the constraint info in terms of the new auto. */
31040 }
31042 }
31044 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
31045 'decltype(auto)' or a deduced class template. */
31047 bool
31049 {
31054 else
31056 }
31058 /* for_each_template_parm callback for type_uses_auto. */
31060 int
31062 {
31064 }
31066 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
31067 a use of `auto'. Returns NULL_TREE otherwise. */
31069 tree
31071 {
31075 {
31076 /* The Concepts TS allows multiple autos in one type-specifier; just
31077 return the first one we find, do_auto_deduction will collect all of
31078 them. */
31082 else
31084 }
31085 else
31087 }
31089 /* Report ill-formed occurrences of auto types in ARGUMENTS. If
31090 concepts are enabled, auto is acceptable in template arguments, but
31091 only when TEMPL identifies a template class. Return TRUE if any
31092 such errors were reported. */
31094 bool
31096 {
31098 /* Only the concepts TS allows 'auto' as a type-id; it'd otherwise
31099 have already been rejected by the parser more generally. */
31102 /* If there were previous errors, nevermind. */
31106 /* If TMPL is an identifier, we're parsing and we can't tell yet
31107 whether TMPL is supposed to be a type, a function or a variable.
31108 We'll only be able to tell during template substitution, so we
31109 expect to be called again then. If concepts are enabled and we
31110 know we have a type, we're ok. */
31117 /* Quickly search for any occurrences of auto; usually there won't
31118 be any, and then we'll avoid allocating the vector. */
31126 {
31131 }
31134 }
31136 /* Recursively walk over && expressions searching for EXPR. Return a reference
31137 to that expression. */
31140 {
31144 {
31149 }
31151 }
31153 /* Convert the generic type parameters in PARM that match the types given in the
31154 range [START_IDX, END_IDX) from the current_template_parms into generic type
31155 packs. */
31157 tree
31159 {
31170 {
31171 /* Create a distinct parameter pack type from the current parm and add it
31172 to the replacement args to tsubst below into the generic function
31173 parameter. */
31187 /* Replace the current template parameter with new pack. */
31190 /* Surgically adjust the associated constraint of adjusted parameter
31191 and it's corresponding contribution to the current template
31192 requirements. */
31194 {
31200 /* If there was a constraint, we also need to replace that in
31201 the template requirements, which we've already built. */
31205 }
31206 }
31212 /* If there are more levels then build up the replacement with the outer
31213 template parms. */
31217 replacement);
31220 }
31222 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
31223 0..N-1. */
31225 void
31227 {
31230 integer_type_node,
31231 NULL_TREE),
31235 CP_BUILT_IN_INTEGER_PACK);
31236 }
31238 /* Walk the decl or type specialization table calling FN on each
31239 entry. */
31241 void
31245 {
31251 }
31253 /* Lookup the specialization of *ELT, in the decl or type
31254 specialization table. Return the SPEC that's already there, or
31255 NULL if nothing. */
31257 tree
31259 {
31269 }
31271 /* Return flags encoding whether SPEC is on the instantiation and/or
31272 specialization lists of TMPL. */
31274 unsigned
31276 {
31282 {
31285 }
31290 /* Only need to search if DECL is a partial specialization. */
31294 {
31297 }
31300 }
31302 /* Add a new specialization described by SPEC. DECL is the
31303 maybe-template decl and FLAGS is as returned from
31304 get_mergeable_specialization_flags. */
31306 void
31309 {
31312 {
31321 {
31324 }
31325 }
31328 {
31331 /* We don't distinguish different constrained partial type
31332 specializations, so there could be duplicates. Everything else
31333 must be new. */
31335 {
31341 }
31342 }
31349 {
31350 /* A partial specialization. */
31355 }
31356 }
31358 /* Set up the hash tables for template instantiations. */
31360 void
31362 {
31368 }
31370 /* Print stats about the template hash tables for -fstats. */
31372 void
31374 {
31383 }
31385 #if CHECKING_P
31389 /* Verify that build_non_dependent_expr () works, for various expressions,
31390 and that location wrappers don't affect the results. */
31392 static void
31394 {
31397 /* Verify constants, without and with location wrappers. */
31414 }
31416 /* Verify that type_dependent_expression_p () works correctly, even
31417 in the presence of location wrapper nodes. */
31419 static void
31421 {
31426 /* If no templates are involved, nothing is type-dependent. */
31432 /* Within a template, an unresolved name is always type-dependent. */
31435 /* Ensure it copes with NULL_TREE and errors. */
31439 /* A USING_DECL in a template should be type-dependent, even if wrapped
31440 with a location wrapper (PR c++/83799). */
31449 }
31451 /* Run all of the selftests within this file. */
31453 void
31455 {
31458 }