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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. */
9924 {
9935 }
9937 /* Calculate the BOUND_ARGS. These will be the args that are
9938 actually tsubst'd into the definition to create the
9939 instantiation. */
9944 /* We were unable to bind the arguments. */
9947 /* In the scope of a template class, explicit references to the
9948 template class refer to the type of the template, not any
9949 instantiation of it. For example, in:
9951 template <class T> class C { void f(C<T>); }
9953 the `C<T>' is just the same as `C'. Outside of the
9954 class, however, such a reference is an instantiation. */
9958 {
9963 }
9965 /* If we already have this specialization, return it. */
9975 /* If the template's constraints are not satisfied,
9976 then we cannot form a valid type.
9978 Note that the check is deferred until after the hash
9979 lookup. This prevents redundant checks on previously
9980 instantiated specializations. */
9984 {
9986 {
9987 auto_diagnostic_group d;
9990 }
9992 }
9996 /* If the deduced arguments are invalid, then the binding
9997 failed. */
10001 complain))
10008 /* This occurs when the user has tried to define a tagged type
10009 in a scope that forbids it. We emitted an error during the
10010 parse. We didn't complete the bail out then, so here we
10011 are. */
10016 {
10018 /* If the context of the partially instantiated template is
10019 already non-dependent, then we might as well use it. */
10021 else
10022 {
10025 /* Try completing the enclosing context if it's not already so. */
10028 {
10031 {
10032 /* Completion could have caused us to register the desired
10033 specialization already, so check the table again. */
10037 }
10038 }
10039 }
10040 }
10041 else
10050 /* Create the type. */
10052 {
10053 /* The user referred to a specialization of an alias
10054 template represented by GEN_TMPL.
10056 [temp.alias]/2 says:
10058 When a template-id refers to the specialization of an
10059 alias template, it is equivalent to the associated
10060 type obtained by substitution of its
10061 template-arguments for the template-parameters in the
10062 type-id of the alias template. */
10065 /* Note that the call above (by indirectly calling
10066 register_specialization in tsubst_decl) registers the
10067 TYPE_DECL representing the specialization of the alias
10068 template. So next time someone substitutes ARGLIST for
10069 the template parms into the alias template (GEN_TMPL),
10070 she'll get that TYPE_DECL back. */
10074 }
10076 {
10078 {
10089 }
10090 else
10091 {
10092 /* We don't want to call start_enum for this type, since
10093 the values for the enumeration constants may involve
10094 template parameters. And, no one should be interested
10095 in the enumeration constants for such a type. */
10098 }
10102 }
10104 {
10105 /* Lambda closures are regenerated in tsubst_lambda_expr, not
10106 instantiated here. */
10114 /* A local class. Make sure the decl gets registered properly. */
10121 /* This instantiation is another name for the primary
10122 template type. Set the TYPE_CANONICAL field
10123 appropriately. */
10127 }
10128 else
10131 /* If we called start_enum or pushtag above, this information
10132 will already be set up. */
10135 {
10142 }
10145 /* Although GEN_TMPL is the TEMPLATE_DECL, it has the same value
10146 of export flag. We want to propagate this because it might
10147 be a friend declaration that pushes a new hidden binding. */
10151 {
10157 {
10160 }
10161 }
10165 {
10169 {
10170 tree attributes
10178 }
10179 }
10181 /* Let's consider the explicit specialization of a member
10182 of a class template specialization that is implicitly instantiated,
10183 e.g.:
10184 template<class T>
10185 struct S
10186 {
10187 template<class U> struct M {}; //#0
10188 };
10190 template<>
10191 template<>
10192 struct S<int>::M<char> //#1
10193 {
10194 int i;
10195 };
10196 [temp.expl.spec]/4 says this is valid.
10198 In this case, when we write:
10199 S<int>::M<char> m;
10201 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
10202 the one of #0.
10204 When we encounter #1, we want to store the partial instantiation
10205 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
10207 For all cases other than this "explicit specialization of member of a
10208 class template", we just want to store the most general template into
10209 the CLASSTYPE_TI_TEMPLATE of M.
10211 This case of "explicit specialization of member of a class template"
10212 only happens when:
10213 1/ the enclosing class is an instantiation of, and therefore not
10214 the same as, the context of the most general template, and
10215 2/ we aren't looking at the partial instantiation itself, i.e.
10216 the innermost arguments are not the same as the innermost parms of
10217 the most general template.
10219 So it's only when 1/ and 2/ happens that we want to use the partial
10220 instantiation of the member template in lieu of its most general
10221 template. */
10225 /* the enclosing class must be an instantiation... */
10228 {
10232 tree partial_inst_args =
10239 use_partial_inst_tmpl =
10240 /*...and we must not be looking at the partial instantiation
10241 itself. */
10243 partial_inst_args);
10244 }
10247 /* This case is easy; there are no member templates involved. */
10249 else
10250 {
10251 /* This is a full instantiation of a member template. Find
10252 the partial instantiation of which this is an instance. */
10254 /* Temporarily reduce by one the number of levels in the ARGLIST
10255 so as to avoid comparing the last set of arguments. */
10257 /* We don't use COMPLAIN in the following call because this isn't
10258 the immediate context of deduction. For instance, tf_partial
10259 could be set here as we might be at the beginning of template
10260 argument deduction when any explicitly specified template
10261 arguments are substituted into the function type. tf_partial
10262 could lead into trouble because we wouldn't find the partial
10263 instantiation that might have been created outside tf_partial
10264 context, because the levels of template parameters wouldn't
10265 match, because in a tf_partial context, tsubst doesn't reduce
10266 TEMPLATE_PARM_LEVEL. */
10269 /* FOUND is either a proper class type, or an alias
10270 template specialization. In the later case, it's a
10271 TYPE_DECL, resulting from the substituting of arguments
10272 for parameters in the TYPE_DECL of the alias template
10273 done earlier. So be careful while getting the template
10274 of FOUND. */
10276 ? found
10283 {
10284 /* If this partial instantiation is specialized, we want to
10285 use it for hash table lookup. */
10289 }
10290 }
10292 /* Build template info for the new specialization. */
10302 /* Note this use of the partial instantiation so we can check it
10303 later in maybe_process_partial_specialization. */
10311 /* Now that the type has been registered on the instantiations
10312 list, we set up the enumerators. Because the enumeration
10313 constants may involve the enumeration type itself, we make
10314 sure to register the type first, and then create the
10315 constants. That way, doing tsubst_expr for the enumeration
10316 constants won't result in recursive calls here; we'll find
10317 the instantiation and exit above. */
10321 /* If the type makes use of template parameters, the
10322 code that generates debugging information will crash. */
10325 /* Possibly limit visibility based on template args. */
10332 }
10333 }
10335 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
10337 tree
10339 {
10343 /* The type of the expression is NULL_TREE since the template-id could refer
10344 to an explicit or partial specialization. */
10346 }
10348 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR if it's
10349 not dependent. */
10351 tree
10353 {
10357 /* If the template or arguments are dependent, then we
10358 can't resolve the TEMPLATE_ID_EXPR yet. */
10369 {
10371 {
10372 auto_diagnostic_group d;
10375 }
10377 }
10380 }
10382 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
10383 TARGS template args, and instantiate it if it's not dependent. */
10385 tree
10387 tsubst_flags_t complain)
10388 {
10390 /* We may be called while doing a partial substitution, but the
10391 type of the variable template may be auto, in which case we
10392 will call do_auto_deduction in mark_used (which clears tf_partial)
10393 and the auto must be properly reduced at that time for the
10394 deduction to work. */
10399 }
10401 /* If the set of template parameters PARMS contains a template parameter
10402 at the given LEVEL and INDEX, then return this parameter. Otherwise
10403 return NULL_TREE. */
10405 static tree
10407 {
10416 }
10418 /* Return the TREE_LIST for the template parameter from PARMS that positionally
10419 corresponds to the template parameter PARM, or else return NULL_TREE. */
10421 static tree
10423 {
10427 }
10429 /* As above, but pull out the actual parameter. */
10431 static tree
10433 {
10439 /* As in template_parm_to_arg. */
10442 else
10447 }
10448 \f
10449 struct pair_fn_data
10450 {
10451 tree_fn_t fn;
10452 tree_fn_t any_fn;
10454 /* True when we should also visit template parameters that occur in
10455 non-deduced contexts. */
10458 };
10460 /* Called from for_each_template_parm via walk_tree. */
10462 static tree
10464 {
10471 #define WALK_SUBTREE(NODE) \
10472 do \
10473 { \
10474 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
10475 pfd->include_nondeduced_p, \
10476 pfd->any_fn); \
10477 if (result) goto out; \
10478 } \
10479 while (0)
10489 {
10493 /* Fall through. */
10499 else
10509 /* Since we're not going to walk subtrees, we have to do this
10510 explicitly here. */
10512 /* Fall through. */
10515 /* Check the return type. */
10518 /* Check the parameter types. Since default arguments are not
10519 instantiated until they are needed, the TYPE_ARG_TYPES may
10520 contain expressions that involve template parameters. But,
10521 no-one should be looking at them yet. And, once they're
10522 instantiated, they don't contain template parameters, so
10523 there's no point in looking at them then, either. */
10524 {
10525 tree parm;
10530 /* Since we've already handled the TYPE_ARG_TYPES, we don't
10531 want walk_tree walking into them itself. */
10533 }
10536 {
10540 }
10556 {
10559 }
10582 /* Record template parameters such as `T' inside `TT<T>'. */
10584 /* Fall through. */
10596 /* A template template parameter is encountered. */
10600 /* Already substituted template template parameter */
10605 /* A template-id in a TYPENAME_TYPE might be a deduced context after
10606 partial instantiation. */
10613 /* If there's no type, then this thing must be some expression
10614 involving template parameters. */
10624 /* These are non-deduced contexts. */
10646 }
10648 #undef WALK_SUBTREE
10650 /* We didn't find any template parameters we liked. */
10651 out:
10653 }
10655 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
10656 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
10657 call FN with the parameter and the DATA.
10658 If FN returns nonzero, the iteration is terminated, and
10659 for_each_template_parm returns 1. Otherwise, the iteration
10660 continues. If FN never returns a nonzero value, the value
10661 returned by for_each_template_parm is 0. If FN is NULL, it is
10662 considered to be the function which always returns 1.
10664 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
10665 parameters that occur in non-deduced contexts. When false, only
10666 visits those template parameters that can be deduced. */
10668 static tree
10672 tree_fn_t any_fn)
10673 {
10675 tree result;
10677 /* Set up. */
10683 /* Walk the tree. (Conceptually, we would like to walk without
10684 duplicates, but for_each_template_parm_r recursively calls
10685 for_each_template_parm, so we would need to reorganize a fair
10686 bit to use walk_tree_without_duplicates, so we keep our own
10687 visited list.) */
10690 else
10693 for_each_template_parm_r,
10697 /* Clean up. */
10699 {
10702 }
10705 }
10707 struct find_template_parameter_info
10708 {
10712 {}
10718 tree ctx_parms;
10725 };
10727 /* Appends the declaration of T to the list in DATA. */
10729 static int
10731 {
10734 /* Template parameters declared within the expression are not part of
10735 the parameter mapping. For example, in this concept:
10737 template<typename T>
10738 concept C = requires { <expr> } -> same_as<int>;
10740 the return specifier same_as<int> declares a new decltype parameter
10741 that must not be part of the parameter mapping. The same is true
10742 for generic lambda parameters, lambda template parameters, etc. */
10750 /* We want the underlying TEMPLATE_TEMPLATE_PARM, not the
10751 BOUND_TEMPLATE_TEMPLATE_PARM itself. */
10754 /* This template parameter might be an argument to a cached dependent
10755 specalization that was formed earlier inside some other template, in
10756 which case the parameter is not among the ones that are in-scope.
10757 Look in CTX_PARMS to find the corresponding in-scope template
10758 parameter, and use it instead. */
10762 /* Arguments like const T yield parameters like const T. This means that
10763 a template-id like X<T, const T> would yield two distinct parameters:
10764 T and const T. Adjust types to their unqualified versions. */
10768 {
10769 /* Append T to PARM_LIST. */
10773 }
10775 /* Verify the parameter we found has a valid index. */
10777 {
10783 }
10786 }
10788 /* Ensure that we recursively examine certain terms that are not normally
10789 visited in for_each_template_parm_r. */
10791 static int
10793 {
10796 #define WALK_SUBTREE(NODE) \
10797 do \
10798 { \
10799 for_each_template_parm (NODE, keep_template_parm, data, \
10800 &ftpi->visited, true, \
10801 any_template_parm_r); \
10802 } \
10803 while (0)
10805 /* A mention of a member alias/typedef is a use of all of its template
10806 arguments, including those from the enclosing class, so we don't use
10807 alias_template_specialization_p here. */
10813 {
10815 /* Type constraints of a placeholder type may contain parameters. */
10822 /* Search through references to variable templates. */
10832 /* If T is a member template that shares template parameters with
10833 ctx_parms, we need to mark all those parameters for mapping.
10834 To that end, it should suffice to just walk the DECL_CONTEXT of
10835 the template (assuming the template is not overly general). */
10840 {
10841 /* Look in the parms and body. */
10845 }
10850 /* The conversion-type-id of a conversion operator may be dependent. */
10861 }
10863 /* Keep walking. */
10865 }
10867 /* Look through T for template parameters. */
10869 tree
10871 {
10874 any_template_parm_r);
10875 }
10877 /* As above, but also recursively look into the default arguments of template
10878 parameters we found. Used for alias CTAD. */
10880 tree
10882 {
10885 /* Since newly found parms are added to the end of the list, we
10886 can just walk it until we reach the end. */
10888 {
10893 }
10895 }
10897 /* True if PARM was found by a previous call to find_in. PARM can be a
10898 TREE_LIST, a DECL_TEMPLATE_PARM_P, or a TEMPLATE_PARM_P. */
10900 bool
10902 {
10907 else
10911 }
10913 /* Returns a list of unique template parameters found within T, where CTX_PARMS
10914 are the template parameters in scope. */
10916 tree
10918 {
10925 }
10927 /* Returns true if T depends on any template parameter. */
10929 bool
10931 {
10935 /* Namespaces can't depend on any template parameters. */
10951 else
10953 }
10955 /* Returns true if T depends on any template parameter with level LEVEL. */
10957 bool
10959 {
10962 }
10964 /* Returns true if the signature of DECL depends on any template parameter from
10965 its enclosing class. */
10967 static bool
10969 {
10978 {
10981 {
10986 template_parm_outer_level,
10996 }
10997 }
11001 }
11003 /* Returns true if the constraints of DECL depend on any template parameters
11004 from its enclosing scope. */
11006 bool
11008 {
11019 }
11021 /* Returns TRUE iff INST is an instantiation we don't need to do in an
11022 ill-formed translation unit, i.e. a variable or function that isn't
11023 usable in a constant expression. */
11027 {
11033 }
11035 /* Returns TRUE iff we should refuse to instantiate DECL because it's
11036 neglectable and instantiated from within an erroneous instantiation. */
11038 static bool
11040 {
11046 /* Avoid instantiating members of an ill-formed class. */
11047 bool refuse
11052 {
11057 }
11060 {
11061 /* Don't warn about it not being defined. */
11063 tree clone;
11066 }
11068 }
11076 /* We're starting to instantiate D; record the template instantiation context
11077 at LOC for diagnostics and to restore it later. */
11079 bool
11081 {
11085 {
11086 /* Tell error.cc not to try to instantiate any templates. */
11089 "template instantiation depth exceeds maximum of %d"
11091 max_tinst_depth);
11093 }
11095 /* If the current instantiation caused problems, don't let it instantiate
11096 anything else. Do allow deduction substitution and decls usable in
11097 constant expressions. */
11099 {
11100 /* Avoid no_linkage_errors and unused function (and all other)
11101 warnings for this decl. */
11104 }
11106 /* When not -quiet, dump template instantiations other than functions, since
11107 announce_function will take care of those. */
11129 }
11131 /* We're starting substitution of TMPL<ARGS>; record the template
11132 substitution context for diagnostics and to restore it later. */
11134 bool
11136 {
11138 }
11140 /* We're starting to instantiate D; record INPUT_LOCATION and the
11141 template instantiation context for diagnostics and to restore it
11142 later. */
11144 bool
11146 {
11148 }
11150 /* Likewise, but record LOC as the program location. */
11152 bool
11154 {
11157 }
11159 /* We're done instantiating this template; return to the instantiation
11160 context. */
11162 void
11164 {
11165 /* Restore the filename and line number stashed away when we started
11166 this instantiation. */
11170 }
11172 /* We're instantiating a deferred template; restore the template
11173 instantiation context in which the instantiation was requested, which
11174 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
11176 static tree
11178 {
11190 }
11192 /* Returns the TINST_LEVEL which gives the original instantiation
11193 context. */
11197 {
11203 }
11205 /* True iff T is a friend function declaration that is not itself a template
11206 and is not defined in a class template. */
11208 bool
11210 {
11213 {
11217 /* DECL_FRIEND_CONTEXT is set for a friend defined in class. */
11220 /* Non-templated friends in a class template are still represented with a
11221 TEMPLATE_DECL; check that its primary template is the befriending
11222 class. Note that DECL_PRIMARY_TEMPLATE is null for
11223 template <class T> friend A<T>::f(); */
11227 }
11228 else
11230 }
11232 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
11233 vector of template arguments, as for tsubst.
11235 Returns an appropriate tsubst'd friend declaration. */
11237 static tree
11239 {
11240 tree new_friend;
11245 /* This was a friend declared with an explicit template
11246 argument list, e.g.:
11248 friend void f<>(T);
11250 to indicate that f was a template instantiation, not a new
11251 function declaration. Now, we have to figure out what
11252 instantiation of what template. */
11253 {
11255 tree new_args;
11256 tree tmpl;
11259 /* Friend functions are looked up in the containing namespace scope.
11260 We must enter that scope, to avoid finding member functions of the
11261 current class with same name. */
11275 tsk_none);
11277 }
11283 /* The NEW_FRIEND will look like an instantiation, to the
11284 compiler, but is not an instantiation from the point of view of
11285 the language. For example, we might have had:
11287 template <class T> struct S {
11288 template <class U> friend void f(T, U);
11289 };
11291 Then, in S<int>, template <class U> void f(int, U) is not an
11292 instantiation of anything. */
11296 {
11302 /* Substitute TEMPLATE_PARMS_CONSTRAINTS so that parameter levels will
11303 match in decls_match. */
11308 {
11310 /* As well as each TEMPLATE_PARM_CONSTRAINTS. */
11312 tf_warning_or_error);
11313 }
11314 }
11316 /* The mangled name for the NEW_FRIEND is incorrect. The function
11317 is not a template instantiation and should not be mangled like
11318 one. Therefore, we forget the mangling here; we'll recompute it
11319 later if we need it. */
11321 {
11324 }
11327 {
11328 tree old_decl;
11329 tree ns;
11331 /* We must save some information from NEW_FRIEND before calling
11332 duplicate decls since that function will free NEW_FRIEND if
11333 possible. */
11337 (new_friend_template_info
11344 {
11345 /* This declaration is a `primary' template. */
11350 }
11352 /* Only define a constrained hidden friend when satisfied. */
11355 /* Inside pushdecl_namespace_level, we will push into the
11356 current namespace. However, the friend function should go
11357 into the namespace of the template. */
11367 {
11368 /* This new friend declaration matched an existing
11369 declaration. For example, given:
11371 template <class T> void f(T);
11372 template <class U> class C {
11373 template <class T> friend void f(T) {}
11374 };
11376 the friend declaration actually provides the definition
11377 of `f', once C has been instantiated for some type. So,
11378 old_decl will be the out-of-class template declaration,
11379 while new_friend is the in-class definition.
11381 But, if `f' was called before this point, the
11382 instantiation of `f' will have DECL_TI_ARGS corresponding
11383 to `T' but not to `U', references to which might appear
11384 in the definition of `f'. Previously, the most general
11385 template for an instantiation of `f' was the out-of-class
11386 version; now it is the in-class version. Therefore, we
11387 run through all specialization of `f', adding to their
11388 DECL_TI_ARGS appropriately. In particular, they need a
11389 new set of outer arguments, corresponding to the
11390 arguments for this class instantiation.
11392 The same situation can arise with something like this:
11394 friend void f(int);
11395 template <class T> class C {
11396 friend void f(T) {}
11397 };
11399 when `C<int>' is instantiated. Now, `f(int)' is defined
11400 in the class. */
11403 /* On the other hand, if the in-class declaration does
11404 *not* provide a definition, then we don't want to alter
11405 existing definitions. We can just leave everything
11406 alone. */
11407 ;
11408 else
11409 {
11413 /* Overwrite whatever template info was there before, if
11414 any, with the new template information pertaining to
11415 the declaration. */
11419 {
11420 /* We should have called reregister_specialization in
11421 duplicate_decls. */
11426 /* Instantiate it if the global has already been used. */
11430 }
11431 else
11432 {
11433 tree t;
11435 /* Indicate that the old function template is a partial
11436 instantiation. */
11444 /* Reassign any specializations already in the hash table
11445 to the new more general template, and add the
11446 additional template args. */
11450 {
11452 spec_entry elt;
11464 register_specialization
11467 }
11469 }
11470 }
11472 /* The information from NEW_FRIEND has been merged into OLD_DECL
11473 by duplicate_decls. */
11475 }
11477 /* We've just introduced a namespace-scope function in the purview
11478 without necessarily having opened the enclosing namespace, so
11479 make sure the namespace is in the purview now too. */
11484 }
11485 else
11486 {
11490 /* In the code
11491 template <class T> class C {
11492 template <class U> friend void C1<U>::f (); // case 1
11493 friend void C2<T>::f (); // case 2
11494 };
11495 we only need to make sure CONTEXT is a complete type for
11496 case 2. To distinguish between the two cases, we note that
11497 CONTEXT of case 1 remains dependent type after tsubst while
11498 this isn't true for case 2. */
11508 {
11510 /* do_friend adds the TEMPLATE_DECL for any member friend
11511 template even if it isn't a member template, i.e.
11512 template <class T> friend A<T>::f();
11513 Look through it in that case. */
11517 /* Check to see that the declaration is really present, and,
11518 possibly obtain an improved declaration. */
11523 }
11524 }
11527 }
11529 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
11530 template arguments, as for tsubst.
11532 Returns an appropriate tsubst'd friend type or error_mark_node on
11533 failure. */
11535 static tree
11537 {
11538 tree tmpl;
11541 {
11544 }
11549 else
11550 {
11553 }
11559 {
11560 /* The friend template has already been declared. Just
11561 check to see that the declarations match, and install any new
11562 default parameters. We must tsubst the default parameters,
11563 of course. We only need the innermost template parameters
11564 because that is all that redeclare_class_template will look
11565 at. */
11568 {
11572 tf_warning_or_error);
11582 }
11583 }
11584 else
11585 {
11586 /* The friend template has not already been declared. In this
11587 case, the instantiation of the template class will cause the
11588 injection of this template into the namespace scope. */
11592 {
11593 /* The new TMPL is not an instantiation of anything, so we
11594 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
11595 for the new type because that is supposed to be the
11596 corresponding template decl, i.e., TMPL. */
11603 /* Substitute into and set the constraints on the new declaration. */
11605 {
11613 }
11615 /* Inject this template into the enclosing namspace scope. */
11617 }
11618 }
11622 else
11626 }
11628 /* Returns zero if TYPE cannot be completed later due to circularity.
11629 Otherwise returns one. */
11631 static int
11633 {
11643 else
11645 }
11650 /* Instantiate the contract statement. */
11652 static tree
11654 tree in_decl)
11655 {
11661 /* Rebuild the result variable. */
11663 {
11671 /* Make sure the postcondition is valid. */
11677 /* Make the variable available for lookup. */
11679 }
11681 /* Instantiate the condition. If the return type is undeduced, process
11682 the expression as if inside a template to avoid spurious type errors. */
11692 /* And the comment. */
11697 }
11699 /* Update T by instantiating its contract attribute. */
11701 static void
11704 {
11705 /* For non-specializations, adjust the current declaration to the most general
11706 version of in_decl. Because we defer the instantiation of contracts as long
11707 as possible, they are still written in terms of the parameters (and return
11708 type) of the most general template. */
11715 /* Get the contract to be instantiated. */
11718 /* Use the complete set of template arguments for instantiation. The
11719 contract may not have been instantiated and still refer to outer levels
11720 of template parameters. */
11723 /* For member functions, make this available for semantic analysis. */
11727 {
11731 }
11738 /* Rebuild the attribute. */
11740 }
11742 /* Rebuild the attribute list for DECL, substituting into contracts
11743 as needed. */
11745 void
11747 {
11750 {
11753 }
11755 }
11757 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
11758 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
11760 static tree
11763 {
11766 /* Note that contract attributes are never substituted from this function.
11767 Their instantiation is triggered by regenerate_from_template_decl when
11768 we instantiate the body of the function. */
11776 {
11783 clauses
11787 else
11789 }
11793 {
11804 {
11808 {
11810 {
11818 }
11819 else
11820 {
11824 {
11825 bool allow_string
11837 {
11838 location_t loc
11840 match_loc);
11846 "integer expression or string "
11848 else
11852 }
11855 {
11856 location_t loc
11858 match_loc);
11862 }
11864 }
11865 }
11866 }
11867 }
11869 }
11870 /* If the first attribute argument is an identifier, don't
11871 pass it through tsubst. Attributes like mode, format,
11872 cleanup and several target specific attributes expect it
11873 unmodified. */
11875 {
11876 tree chain
11880 }
11882 {
11883 /* An attribute pack expansion. */
11892 {
11896 }
11898 }
11899 else
11907 }
11909 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
11910 unchanged or a new TREE_LIST chain. */
11912 static tree
11915 {
11920 {
11924 }
11928 {
11931 {
11934 {
11940 }
11941 }
11943 }
11946 }
11948 /* Apply any attributes which had to be deferred until instantiation
11949 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
11950 ARGS, COMPLAIN, IN_DECL are as tsubst. Returns true normally,
11951 false on error. */
11953 static bool
11956 {
11957 tree t;
11964 {
11968 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
11969 to our attributes parameter. */
11971 }
11972 else
11973 {
11975 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
11976 lookup_template_class_1, and should be preserved. */
11980 }
11982 /* save_template_attributes puts the dependent attributes at the beginning of
11983 the list; find the non-dependent ones. */
11989 /* Apply any non-dependent attributes. */
11995 /* And then any dependent ones. */
11999 {
12004 {
12007 }
12010 }
12012 /* cplus_decl_attributes can add some attributes implicitly. For templates,
12013 those attributes should have been added already when those templates were
12014 parsed, and shouldn't be added based on from which context they are
12015 first time instantiated. */
12018 optimization_default_node);
12021 NULL);
12027 }
12029 /* The template TMPL is being instantiated with the template arguments TARGS.
12030 Perform the access checks that we deferred when parsing the template. */
12032 static void
12034 {
12044 {
12052 /* Make access check error messages point to the location
12053 of the use of the typedef. */
12057 }
12058 }
12060 tree
12062 {
12066 tree typedecl;
12067 tree pbinfo;
12068 tree base_list;
12070 tree fn_context;
12080 /* Figure out which template is being instantiated. */
12084 /* Mark the type as in the process of being defined. */
12087 /* We may be in the middle of deferred access check. Disable
12088 it now. */
12091 /* Determine what specialization of the original template to
12092 instantiate. */
12097 {
12098 /* This TYPE is actually an instantiation of a partial
12099 specialization. We replace the innermost set of ARGS with
12100 the arguments appropriate for substitution. For example,
12101 given:
12103 template <class T> struct S {};
12104 template <class T> struct S<T*> {};
12106 and supposing that we are instantiating S<int*>, ARGS will
12107 presently be {int*} -- but we need {int}. */
12110 }
12111 else
12112 {
12115 }
12117 /* If the template we're instantiating is incomplete, then clearly
12118 there's nothing we can do. */
12120 {
12121 /* We can try again later. */
12124 }
12126 /* If we've recursively instantiated too many templates, stop. */
12134 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
12139 else
12140 {
12143 }
12147 /* Use #pragma pack from the template context. */
12153 /* Set the input location to the most specialized template definition.
12154 This is needed if tsubsting causes an error. */
12168 {
12171 /* Adjust visibility for template arguments. */
12173 }
12179 /* We should never instantiate a nested class before its enclosing
12180 class; we need to look up the nested class by name before we can
12181 instantiate it, and that lookup should instantiate the enclosing
12182 class. */
12187 /* Defer access checking while we substitute into the types named in
12188 the base-clause. */
12191 {
12192 tree pbase_binfo;
12195 /* Substitute into each of the bases to determine the actual
12196 basetypes. */
12198 {
12199 tree base;
12205 {
12206 expanded_bases =
12213 }
12216 {
12218 /* Extract the already-expanded base class. */
12220 else
12221 /* Substitute to figure out the base class. */
12223 NULL_TREE);
12231 }
12232 }
12234 /* The list is now in reverse order; correct that. */
12236 }
12237 /* Now call xref_basetypes to set up all the base-class
12238 information. */
12246 /* Now that our base classes are set up, enter the scope of the
12247 class, so that name lookups into base classes, etc. will work
12248 correctly. This is precisely analogous to what we do in
12249 begin_class_definition when defining an ordinary non-template
12250 class, except we also need to push the enclosing classes. */
12253 /* Now check accessibility of the types named in its base-clause,
12254 relative to the scope of the class. */
12257 /* A vector to hold members marked with attribute used. */
12260 /* Now members are processed in the order of declaration. */
12263 {
12267 {
12269 {
12271 /* A closure type for a lambda in an NSDMI or default argument.
12272 Ignore it; it will be regenerated when needed. */
12275 /* If the member is a class template, we've
12276 already substituted its type. */
12286 {
12289 /* Now, install the tag. We don't use pushtag
12290 because that does too much work -- creating an
12291 implicit typedef, which we've already done. */
12296 }
12297 }
12299 {
12300 tree r;
12310 /* Instantiate members marked with attribute used. */
12316 }
12319 /* A closure type for a lambda in an NSDMI or default argument.
12321 else
12322 {
12323 /* Build new TYPE_FIELDS. */
12327 {
12328 tree r;
12333 /* The file and line for this declaration, to
12334 assist in error message reporting. Since we
12335 called push_tinst_level above, we don't need to
12336 restore these. */
12346 {
12347 /* A capture pack became multiple fields. */
12350 }
12353 {
12357 {
12358 /* In [temp.inst]:
12360 [t]he initialization (and any associated
12361 side-effects) of a static data member does
12362 not occur unless the static data member is
12363 itself used in a way that requires the
12364 definition of the static data member to
12365 exist.
12367 Therefore, we do not substitute into the
12368 initialized for the static data member here. */
12369 finish_static_data_member_decl
12375 /* Instantiate members marked with attribute used. */
12378 }
12380 {
12381 /* Determine whether R has a valid type and can be
12382 completed later. If R is invalid, then its type
12383 is replaced by error_mark_node. */
12389 {
12390 /* If R's type couldn't be completed and
12391 it isn't a flexible array member (whose
12392 type is incomplete by definition) give
12393 an error. */
12396 }
12401 {
12404 }
12408 }
12410 /* If it is a TYPE_DECL for a class-scoped
12411 ENUMERAL_TYPE, such a thing will already have
12412 been added to the field list by tsubst_enum
12413 in finish_member_declaration case above. */
12417 {
12420 }
12421 }
12422 }
12423 }
12424 }
12425 else
12426 {
12429 {
12430 /* Build new CLASSTYPE_FRIEND_CLASSES. */
12434 {
12435 /* template <class T> friend class C; */
12437 }
12439 {
12440 /* template <class T> friend class C::D; */
12445 }
12448 {
12449 /* This could be either
12451 friend class T::C;
12453 when dependent_type_p is false or
12455 template <class U> friend class T::C;
12457 otherwise. */
12458 /* Bump processing_template_decl in case this is something like
12459 template <class T> friend struct A<T>::B. */
12464 }
12466 /* friend class C<T>; */
12470 /* Otherwise it's
12472 friend class C;
12474 where C is already declared or
12476 friend class C<int>;
12478 We don't have to do anything in these cases. */
12482 }
12483 else
12484 {
12485 /* Build new DECL_FRIENDLIST. */
12486 tree r;
12488 /* The file and line for this declaration, to
12489 assist in error message reporting. Since we
12490 called push_tinst_level above, we don't need to
12491 restore these. */
12495 {
12498 }
12503 {
12506 }
12507 }
12508 }
12509 }
12512 {
12513 /* Restore these before substituting into the lambda capture
12514 initializers. */
12517 }
12519 /* Set the file and line number information to whatever is given for
12520 the class itself. This puts error messages involving generated
12521 implicit functions at a predictable point, and the same point
12522 that would be used for non-template classes. */
12529 /* Remember if instantiating this class ran into errors, so we can avoid
12530 instantiating member functions in limit_bad_template_recursion. We set
12531 this flag even if the problem was in another instantiation triggered by
12532 this one, as that will likely also cause trouble for member functions. */
12536 /* We don't instantiate default arguments for member functions. 14.7.1:
12538 The implicit instantiation of a class template specialization causes
12539 the implicit instantiation of the declarations, but not of the
12540 definitions or default arguments, of the class member functions,
12541 member classes, static data members and member templates.... */
12546 /* Now that we've gone through all the members, instantiate those
12547 marked with attribute used. We must do this in the context of
12548 the class -- not the context we pushed from, as that might be
12549 inside a template and change the behaviour of mark_used. */
12559 /* The vtable for a template class can be emitted in any translation
12560 unit in which the class is instantiated. When there is no key
12561 method, however, finish_struct_1 will already have added TYPE to
12562 the keyed_classes. */
12567 }
12569 tree
12571 {
12572 tree r;
12578 else
12579 {
12585 }
12588 }
12590 /* Given a function parameter pack TMPL_PARM and some function parameters
12591 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
12592 and set *SPEC_P to point at the next point in the list. */
12594 tree
12596 {
12597 /* Collect all of the extra "packed" parameters into an
12598 argument pack. */
12599 tree argpack;
12610 {
12611 /* The instantiation is still a parameter pack; don't wrap it in a
12612 NONTYPE_ARGUMENT_PACK. */
12615 }
12616 else
12617 {
12618 /* Fill in PARMVEC with all of the parameters. */
12622 {
12628 }
12630 /* Build the argument packs. */
12632 }
12636 }
12638 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
12639 NONTYPE_ARGUMENT_PACK. */
12641 static tree
12643 {
12645 }
12647 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
12648 pack expansion with no extra args, 2 if it has extra args, or 0
12649 if it is not a pack expansion. */
12651 static int
12653 {
12655 /* We're being called before this happens in tsubst_pack_expansion. */
12662 /* A decl pack is itself an expansion. */
12669 }
12672 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
12674 static tree
12676 {
12683 }
12685 /* This is a subroutine of tsubst_pack_expansion.
12687 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
12688 mechanism to store the (non complete list of) arguments of the
12689 substitution and return a non substituted pack expansion, in order
12690 to wait for when we have enough arguments to really perform the
12691 substitution. */
12693 static bool
12695 tree parm_packs,
12698 {
12703 /* If one pack has an expansion and another pack has a normal
12704 argument or if one pack has an empty argument and an another
12705 one hasn't then tsubst_pack_expansion cannot perform the
12706 substitution and need to fall back on the
12707 PACK_EXPANSION_EXTRA mechanism. */
12711 {
12712 /* If all the actual packs are pack expansions, we can still
12713 subsitute directly. */
12715 {
12725 }
12727 }
12730 {
12734 parm_pack;
12736 {
12741 /* We can't substitute a pack expansion with extra args into
12742 our pattern. */
12746 else
12748 }
12751 {
12754 }
12755 }
12757 }
12759 /* [temp.variadic]/6 says that:
12761 The instantiation of a pack expansion [...]
12762 produces a list E1,E2, ..., En, where N is the number of elements
12763 in the pack expansion parameters.
12765 This subroutine of tsubst_pack_expansion produces one of these Ei.
12767 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
12768 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
12769 PATTERN, and each TREE_VALUE is its corresponding argument pack.
12770 INDEX is the index 'i' of the element Ei to produce. ARGS,
12771 COMPLAIN, and IN_DECL are the same parameters as for the
12772 tsubst_pack_expansion function.
12774 The function returns the resulting Ei upon successful completion,
12775 or error_mark_node.
12777 Note that this function possibly modifies the ARGS parameter, so
12778 it's the responsibility of the caller to restore it. */
12780 static tree
12782 tree parm_packs,
12784 tree args /* This parm gets
12786 tsubst_flags_t complain,
12787 tree in_decl)
12788 {
12789 tree t;
12792 /* For each parameter pack, change the substitution of the parameter
12793 pack to the ith argument in its argument pack, then expand the
12794 pattern. */
12796 {
12801 ith_elem_is_expansion |=
12804 /* Select the Ith argument from the pack. */
12808 {
12810 {
12815 }
12816 else
12818 }
12819 else
12820 {
12825 {
12827 /* Update the corresponding argument. */
12829 }
12830 else
12831 /* Re-use the ARGUMENT_PACK_SELECT. */
12833 }
12835 }
12837 /* Substitute into the PATTERN with the (possibly altered)
12838 arguments. */
12840 /* Expanding a fixed parameter pack from
12841 coerce_template_parameter_pack. */
12847 else
12848 {
12851 /* When expanding the fake auto... pack expansion from add_capture, we
12852 need to mark that the expansion is no longer a pack. */
12854 }
12856 /* If the Ith argument pack element is a pack expansion, then
12857 the Ith element resulting from the substituting is going to
12858 be a pack expansion as well. */
12863 }
12865 /* When the unexpanded parameter pack in a fold expression expands to an empty
12866 sequence, the value of the expression is as follows; the program is
12867 ill-formed if the operator is not listed in this table.
12869 && true
12870 || false
12871 , void() */
12873 tree
12875 {
12879 {
12888 }
12894 }
12896 /* Given a fold-expression T and a current LEFT and RIGHT operand,
12897 form an expression that combines the two terms using the
12898 operator of T. */
12900 static tree
12902 {
12907 // Handle compound assignment operators.
12914 {
12923 complain);
12924 }
12925 }
12927 /* Substitute ARGS into the pack of a fold expression T. */
12931 {
12933 }
12935 /* Substitute ARGS into the pack of a fold expression T. */
12939 {
12941 }
12943 /* Expand a PACK of arguments into a grouped as left fold.
12944 Given a pack containing elements A0, A1, ..., An and an
12945 operator @, this builds the expression:
12947 ((A0 @ A1) @ A2) ... @ An
12949 Note that PACK must not be empty.
12951 The operator is defined by the original fold expression T. */
12953 static tree
12955 {
12958 {
12961 }
12963 }
12965 /* Substitute into a unary left fold expression. */
12967 static tree
12969 tree in_decl)
12970 {
12975 {
12979 }
12982 else
12984 }
12986 /* Substitute into a binary left fold expression.
12988 Do ths by building a single (non-empty) vector of argumnts and
12989 building the expression from those elements. */
12991 static tree
12993 tree in_decl)
12994 {
13003 {
13008 }
13016 }
13018 /* Expand a PACK of arguments into a grouped as right fold.
13019 Given a pack containing elementns A0, A1, ..., and an
13020 operator @, this builds the expression:
13022 A0@ ... (An-2 @ (An-1 @ An))
13024 Note that PACK must not be empty.
13026 The operator is defined by the original fold expression T. */
13028 tree
13030 {
13031 // Build the expression.
13035 {
13038 }
13040 }
13042 /* Substitute into a unary right fold expression. */
13044 static tree
13046 tree in_decl)
13047 {
13052 {
13056 }
13059 else
13061 }
13063 /* Substitute into a binary right fold expression.
13065 Do ths by building a single (non-empty) vector of arguments and
13066 building the expression from those elements. */
13068 static tree
13070 tree in_decl)
13071 {
13080 {
13085 }
13094 }
13096 /* Walk through the pattern of a pack expansion, adding everything in
13097 local_specializations to a list. */
13099 class el_data
13100 {
13102 /* Set of variables declared within the pattern. */
13104 /* Set of AST nodes that have been visited by the traversal. */
13106 /* List of local_specializations used within the pattern. */
13107 tree extra;
13108 tsubst_flags_t complain;
13109 /* True iff we don't want to walk into unevaluated contexts. */
13111 /* The unevaluated contexts that we avoided walking. */
13116 };
13117 static tree
13119 {
13126 {
13130 }
13133 /* Remember local typedefs (85214). */
13137 {
13143 {
13146 decl2
13152 {
13155 }
13156 }
13157 }
13159 {
13160 /* Since we defer implicit capture, look in the parms and body. */
13166 }
13168 {
13170 /* Don't mess with variables declared within the pattern. */
13173 {
13174 /* Maybe pull out the PARM_DECL for a partial instantiation. */
13177 {
13183 }
13185 {
13186 /* Handle lambda capture here, since we aren't doing any
13187 substitution now, and so tsubst_copy won't call
13188 process_outer_var_ref. */
13192 {
13198 {
13199 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
13200 proxies. */
13202 {
13207 }
13209 }
13210 }
13211 }
13212 }
13216 }
13218 }
13219 static tree
13221 {
13223 /* Walk the pattern twice, ignoring unevaluated operands the first time
13224 around, so that if a local specialization appears in both an evaluated
13225 and unevaluated context we prefer to process it in the evaluated context
13226 (since e.g. process_outer_var_ref is a no-op inside an unevaluated
13227 context). */
13230 /* Now walk the unevaluated contexts we skipped the first time around. */
13233 {
13236 }
13238 }
13240 /* Extract any uses of local_specializations from PATTERN and add them to ARGS
13241 for use in PACK_EXPANSION_EXTRA_ARGS. */
13243 tree
13245 {
13246 /* Make a copy of the extra arguments so that they won't get changed
13247 out from under us. */
13253 }
13255 /* Apply any local specializations from PACK_EXPANSION_EXTRA_ARGS and add the
13256 normal template args to ARGS. */
13258 tree
13260 {
13262 {
13264 {
13265 /* The partial instantiation involved local declarations collected in
13266 extract_local_specs; map from the general template to our local
13267 context. */
13273 /* else inst is already a full instantiation of the pack. */
13275 }
13278 }
13280 {
13281 /* This can happen after dependent substitution into a
13282 requires-expr or a lambda that uses constexpr if. */
13285 }
13286 else
13289 }
13291 /* Substitute ARGS into T, which is an pack expansion
13292 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
13293 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
13294 (if only a partial substitution could be performed) or
13295 ERROR_MARK_NODE if there was an error. */
13296 tree
13298 tree in_decl)
13299 {
13300 tree pattern;
13304 tree result;
13311 /* Add in any args remembered from an earlier partial instantiation. */
13316 /* Determine the argument packs that will instantiate the parameter
13317 packs used in the expansion expression. While we're at it,
13318 compute the number of arguments to be expanded and make sure it
13319 is consistent. */
13322 {
13329 {
13334 in_decl),
13335 complain);
13336 else
13339 complain);
13340 }
13342 {
13344 {
13347 parm_pack);
13349 }
13352 }
13354 {
13355 /* We know we have correct local_specializations if this
13356 expansion is at function scope, or if we're dealing with a
13357 local parameter in a requires expression; for the latter,
13358 tsubst_requires_expr set it up appropriately. */
13361 else
13362 /* We can't rely on local_specializations for a parameter
13363 name used later in a function declaration (such as in a
13364 late-specified return type). Even if it exists, it might
13365 have the wrong value for a recursive call. */
13369 {
13370 /* This parameter pack was used in an unevaluated context. Just
13371 make a dummy decl, since it's only used for its type. */
13376 /* Partial instantiation of the parm_pack, we can't build
13377 up an argument pack yet. */
13379 else
13381 }
13383 /* This argument pack isn't fully instantiated yet. */
13385 }
13387 {
13391 }
13392 else
13393 {
13402 }
13409 /* This can only happen if we forget to expand an argument
13410 pack somewhere else. Just return an error, silently. */
13411 {
13415 }
13418 {
13422 /* Don't bother trying to do a partial substitution with
13423 incomplete packs; we'll try again after deduction. */
13430 {
13435 pattern);
13436 else
13438 pattern);
13440 }
13442 /* Keep track of the parameter packs and their corresponding
13443 argument packs. */
13446 }
13447 else
13448 {
13449 /* We can't substitute for this parameter pack. We use a flag as
13450 well as the missing_level counter because function parameter
13451 packs don't have a level. */
13454 }
13455 }
13457 /* If the expansion is just T..., return the matching argument pack, unless
13458 we need to call convert_from_reference on all the elements. This is an
13459 important optimization; see c++/68422. */
13462 {
13465 /* If the argument pack is a single pack expansion, pull it out. */
13470 /* Types need no adjustment, nor does sizeof..., and if we still have
13471 some pack expansion args we won't do anything yet. */
13476 /* Also optimize expression pack expansions if we can tell that the
13477 elements won't have reference type. */
13483 /* Otherwise use the normal path so we get convert_from_reference. */
13484 }
13486 /* We cannot expand this expansion expression, because we don't have
13487 all of the argument packs we need. */
13489 {
13490 /* We got some full packs, but we can't substitute them in until we
13491 have values for all the packs. So remember these until then. */
13497 }
13499 /* If NEED_LOCAL_SPECIALIZATIONS then we're in a late-specified return
13500 type, so create our own local specializations map; the current map is
13501 either NULL or (in the case of recursive unification) might have
13502 bindings that we don't want to use or alter. */
13507 {
13508 /* There were no real arguments, we're just replacing a parameter
13509 pack with another version of itself. Substitute into the
13510 pattern and return a PACK_EXPANSION_*. The caller will need to
13511 deal with that. */
13514 else
13520 {
13521 /* This is a fake auto... pack expansion created in add_capture with
13522 _PACKS that don't appear in the pattern. Copy one over. */
13529 }
13531 }
13535 /* For each argument in each argument pack, substitute into the
13536 pattern. */
13540 {
13542 i,
13544 in_decl);
13547 {
13550 }
13551 }
13553 /* Update ARGS to restore the substitution from parameter packs to
13554 their argument packs. */
13556 {
13563 else
13564 {
13572 /* Update the corresponding argument. */
13576 else
13578 }
13579 }
13581 /* If the dependent pack arguments were such that we end up with only a
13582 single pack expansion again, there's no need to keep it in a TREE_VEC. */
13588 }
13590 /* Make an argument pack out of the TREE_VEC VEC. */
13592 static tree
13594 {
13595 tree pack;
13599 else
13600 {
13603 }
13606 }
13608 /* Return an exact copy of template args T that can be modified
13609 independently. */
13611 static tree
13613 {
13621 {
13626 }
13632 }
13634 /* Substitute ARGS into the *_ARGUMENT_PACK orig_arg. */
13636 tree
13638 tree in_decl)
13639 {
13640 /* This flag is used only during deduction, and we don't expect to
13641 substitute such ARGUMENT_PACKs. */
13644 /* Substitute into each of the arguments. */
13653 /* If we're substituting into a generic ARGUMENT_PACK for a variadic
13654 template parameter, we might be able to avoid allocating a new
13655 ARGUMENT_PACK and reuse the corresponding ARGUMENT_PACK from ARGS
13656 if the substituted result is identical to it. */
13658 {
13665 {
13668 }
13669 }
13671 tree new_arg;
13673 {
13676 }
13677 else
13678 {
13681 }
13684 }
13686 /* Substitute ARGS into the vector or list of template arguments T. */
13688 tree
13690 {
13694 /* In "sizeof(X<I>)" we need to evaluate "I". */
13695 cp_evaluated ev;
13701 /* True iff the substituted result is identical to T. */
13705 {
13707 tree new_arg;
13714 {
13715 /* Substitute into an expansion expression. */
13719 /* Add to the expanded length adjustment the number of
13720 expanded arguments. We subtract one from this
13721 measurement, because the argument pack expression
13722 itself is already counted as 1 in
13723 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
13724 the argument pack is empty. */
13726 }
13729 else
13738 }
13745 /* If ARGS and T are both multi-level, the substituted result may be
13746 identical to ARGS. */
13751 /* If T appears to be a vector of generic template arguments, the
13752 substituted result may be identical to the corresponding level
13753 from ARGS. */
13755 {
13760 }
13762 /* If the substituted result is identical to MAYBE_REUSE, return
13763 it and avoid allocating a new TREE_VEC, as an optimization. */
13769 /* If T consists of only a pack expansion for which substitution yielded
13770 a TREE_VEC of the expanded elements, then reuse that TREE_VEC instead
13771 of effectively making a copy. */
13777 /* Make space for the expanded arguments coming from template
13778 argument packs. */
13780 /* T can contain TREE_VECs. That happens if T contains the
13781 arguments for a member template.
13782 In that case each TREE_VEC in T represents a level of template
13783 arguments, and T won't carry any non defaulted argument count.
13784 It will rather be the nested TREE_VECs that will carry one.
13785 In other words, T carries a non defaulted argument count only
13786 if it doesn't contain any nested TREE_VEC. */
13788 {
13792 }
13796 {
13801 {
13802 /* Now expand the template argument pack "in place". */
13805 }
13806 else
13807 {
13809 out++;
13810 }
13811 }
13815 }
13817 /* Substitute ARGS into one level PARMS of template parameters. */
13819 static tree
13821 {
13828 {
13836 }
13839 }
13841 /* Return the result of substituting ARGS into the template parameters
13842 given by PARMS. If there are m levels of ARGS and m + n levels of
13843 PARMS, then the result will contain n levels of PARMS. For
13844 example, if PARMS is `template <class T> template <class U>
13845 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
13846 result will be `template <int*, double, class V>'. */
13848 static tree
13850 {
13854 /* When substituting into a template, we must set
13855 PROCESSING_TEMPLATE_DECL as the template parameters may be
13856 dependent if they are based on one-another, and the dependency
13857 predicates are short-circuit outside of templates. */
13864 {
13873 }
13878 }
13880 /* Return the result of substituting ARGS into one template parameter
13881 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
13882 parameter and which TREE_PURPOSE is the default argument of the
13883 template parameter. */
13885 static tree
13887 {
13910 }
13912 /* Substitute in-place the TEMPLATE_PARM_CONSTRAINTS of each template
13913 parameter in PARMS for sake of declaration matching. */
13915 static void
13917 tsubst_flags_t complain)
13918 {
13921 {
13927 }
13929 }
13931 /* Substitute the ARGS into the indicated aggregate (or enumeration)
13932 type T. If T is not an aggregate or enumeration type, it is
13933 handled as if by tsubst. IN_DECL is as for tsubst. If
13934 ENTERING_SCOPE is nonzero, T is the context for a template which
13935 we are presently tsubst'ing. Return the substituted value. */
13937 static tree
13939 tree args,
13940 tsubst_flags_t complain,
13941 tree in_decl,
13943 {
13947 /* Handle typedefs via tsubst so that they get consistently reused. */
13949 {
13954 /* The effect of entering_scope is that for a dependent specialization
13955 A<T>, lookup_template_class prefers to return A's primary template
13956 type instead of the implicit instantiation. So when entering_scope,
13957 we mirror this behavior by inspecting TYPE_CANONICAL appropriately,
13958 taking advantage of the fact that lookup_template_class links the two
13959 types by setting TYPE_CANONICAL of the latter to the former. */
13967 }
13970 {
13978 }
13979 }
13981 /* The part of tsubst_aggr_type that's shared with the RECORD_, UNION_
13982 and ENUMERAL_TYPE cases of tsubst. */
13984 static tree
13986 tree args,
13987 tsubst_flags_t complain,
13988 tree in_decl,
13990 {
13992 {
13995 /* Figure out what arguments are appropriate for the
13996 type we are trying to find. For example, given:
13998 template <class T> struct S;
13999 template <class T, class U> void f(T, U) { S<U> su; }
14001 and supposing that we are instantiating f<int, double>,
14002 then our ARGS will be {int, double}, but, when looking up
14003 S we only want {double}. */
14012 }
14013 else
14014 /* This is not a template type, so there's nothing to do. */
14016 }
14018 /* Map from a FUNCTION_DECL to a vec of default argument instantiations,
14019 indexed in reverse order of the parameters. */
14023 /* Return a reference to the vec* of defarg insts for FN. */
14027 {
14031 tree_vec_map **slot
14034 {
14037 }
14039 }
14041 /* Substitute into the default argument ARG (a default argument for
14042 FN), which has the indicated TYPE. */
14044 tree
14046 tsubst_flags_t complain)
14047 {
14050 /* This can happen in invalid code. */
14054 /* Shortcut {}. */
14069 /* Remember the location of the pointer to the vec rather than the location
14070 of the particular element, in case the vec grows in tsubst_expr. */
14072 /* Index in reverse order to avoid allocating space for initial parameters
14073 that don't have default arguments. */
14080 /* This default argument came from a template. Instantiate the
14081 default argument here, not in tsubst. In the case of
14082 something like:
14084 template <class T>
14085 struct S {
14086 static T t();
14087 void f(T = t());
14088 };
14090 we must be careful to do name lookup in the scope of S<T>,
14091 rather than in the current class. */
14095 /* So in_immediate_context knows this is a default argument. */
14099 /* The default argument expression may cause implicitly defined
14100 member functions to be synthesized, which will result in garbage
14101 collection. We must treat this situation as if we were within
14102 the body of function so as to avoid collecting live data on the
14103 stack. */
14110 /* Make sure the default argument is reasonable. */
14127 }
14129 /* Substitute into all the default arguments for FN. */
14131 static void
14133 {
14134 tree arg;
14135 tree tmpl_args;
14139 /* If this function is not yet instantiated, we certainly don't need
14140 its default arguments. */
14143 /* Don't do this again for clones. */
14149 arg;
14155 complain);
14156 }
14158 /* Hash table mapping a FUNCTION_DECL to its dependent explicit-specifier. */
14161 /* Store a pair to EXPLICIT_SPECIFIER_MAP. */
14163 void
14165 {
14170 }
14172 /* Lookup an element in EXPLICIT_SPECIFIER_MAP. */
14174 tree
14176 {
14178 }
14180 /* Given T, a FUNCTION_TYPE or METHOD_TYPE, construct and return a corresponding
14181 FUNCTION_TYPE or METHOD_TYPE whose return type is RETURN_TYPE, argument types
14182 are ARG_TYPES, and exception specification is RAISES, and otherwise is
14183 identical to T. */
14185 static tree
14188 {
14191 tree new_type;
14193 {
14196 }
14197 else
14198 {
14200 /* Don't pick up extra function qualifiers from the basetype. */
14203 {
14204 /* [temp.deduct]
14206 Type deduction may fail for any of the following
14207 reasons:
14209 -- Attempting to create "pointer to member of T" when T
14210 is not a class type. */
14213 r);
14215 }
14219 }
14225 }
14227 /* Check if the function type of DECL, a FUNCTION_DECL, agrees with the type of
14228 each of its formal parameters. If there is a disagreement then rebuild
14229 DECL's function type according to its formal parameter types, as part of a
14230 resolution for Core issues 1001/1322. */
14232 static void
14234 {
14237 {
14240 {
14244 {
14247 }
14251 }
14252 }
14263 {
14268 }
14270 {
14280 }
14288 }
14290 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
14292 static tree
14294 tree lambda_fntype)
14295 {
14300 /* Nobody should be tsubst'ing into non-template functions. */
14305 {
14308 }
14310 {
14311 /* If T is not dependent, just return it. */
14316 /* A non-templated friend doesn't get DECL_TEMPLATE_INFO. */
14320 /* Calculate the most general template of which R is a
14321 specialization. */
14324 /* We're substituting a lambda function under tsubst_lambda_expr but not
14325 directly from it; find the matching function we're already inside.
14326 But don't do this if T is a generic lambda with a single level of
14327 template parms, as in that case we're doing a normal instantiation. */
14333 /* Calculate the complete set of arguments used to
14334 specialize R. */
14336 (DECL_TEMPLATE_RESULT
14342 /* Check to see if we already have this specialization. */
14344 {
14347 /* The spec for these args might be a partial instantiation of the
14348 template, but here what we want is the FUNCTION_DECL. */
14350 }
14351 }
14352 else
14353 {
14354 /* This special case arises when we have something like this:
14356 template <class T> struct S {
14357 friend void f<int>(int, double);
14358 };
14360 Here, the DECL_TI_TEMPLATE for the friend declaration
14361 will be an IDENTIFIER_NODE. We are being called from
14362 tsubst_friend_function, and we want only to create a
14363 new decl (R) with appropriate types so that we can call
14364 determine_specialization. */
14365 friend_case:
14368 }
14375 /* If this is a static lambda, remove the 'this' pointer added in
14376 tsubst_lambda_expr now that we know the closure type. */
14390 /* If we hit excessive deduction depth, the type is bogus even if
14391 it isn't error_mark_node, so don't build a decl. */
14395 /* We do NOT check for matching decls pushed separately at this
14396 point, as they may not represent instantiations of this
14397 template, and in any case are considered separate under the
14398 discrete model. */
14402 /* Clear out the mangled name and RTL for the instantiation. */
14405 /* Leave DECL_INITIAL set on deleted instantiations. */
14411 /* Handle explicit(dependent-expr). */
14413 {
14421 else
14422 {
14425 }
14426 }
14428 /* OpenMP UDRs have the only argument a reference to the declared
14429 type. We want to diagnose if the declared type is a reference,
14430 which is invalid, but as references to references are usually
14431 quietly merged, diagnose it here. */
14433 {
14434 tree argtype
14439 "reference type %qT in "
14443 argtype);
14444 }
14447 /* Type-conversion operator. Reconstruct the name, in
14448 case it's the name of one of the template's parameters. */
14458 {
14463 }
14472 /* If this is an instantiation of a function with internal
14473 linkage, we already know what object file linkage will be
14474 assigned to the instantiation. */
14483 /* We'll re-clone as appropriate in instantiate_template. */
14486 /* If we aren't complaining now, return on error before we register
14487 the specialization so that we'll complain eventually. */
14493 /* Associate the constraints directly with the instantiation. We
14494 don't substitute through the constraints; that's only done when
14495 they are checked. */
14508 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
14509 this in the special friend case mentioned above where
14510 GEN_TMPL is NULL. */
14512 {
14517 tree new_r
14520 /* We instantiated this while substituting into
14521 the type earlier (template/friend54.C). */
14524 /* We're not supposed to instantiate default arguments
14525 until they are called, for a template. But, for a
14526 declaration like:
14528 template <class T> void f ()
14529 { extern void g(int i = T()); }
14531 we should do the substitution when the template is
14532 instantiated. We handle the member function case in
14533 instantiate_class_template since the default arguments
14534 might refer to other members of the class. */
14539 }
14541 {
14544 }
14545 else
14548 /* Copy the list of befriending classes. */
14552 {
14556 }
14559 {
14563 /* If this is an instantiation of a member template, clone it.
14564 If it isn't, that'll be handled by
14565 clone_constructors_and_destructors. */
14568 }
14574 /* Possibly limit visibility based on template args. */
14577 {
14581 }
14593 }
14595 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
14597 static tree
14600 {
14601 /* We can get here when processing a member function template,
14602 member class template, or template template parameter. */
14605 tree spec;
14606 tree tmpl_args;
14607 tree full_args;
14608 tree r;
14612 {
14613 /* Template template parameter is treated here. */
14617 /* If we get a real template back, return it. This can happen in
14618 the context of most_specialized_partial_spec. */
14621 else
14622 /* The new TEMPLATE_DECL was built in
14623 reduce_template_parm_level. */
14626 }
14629 {
14630 /* We might already have an instance of this template.
14631 The ARGS are for the surrounding class type, so the
14632 full args contain the tsubst'd args for the context,
14633 plus the innermost args from the template decl. */
14637 /* Because this is a template, the arguments will still be
14638 dependent, even after substitution. If
14639 PROCESSING_TEMPLATE_DECL is not set, the dependency
14640 predicates will short-circuit. */
14648 /* If this is a default template template argument,
14649 tsubst might not have changed anything. */
14656 {
14658 /* Type partial instantiations are stored as the type by
14659 lookup_template_class_1, not here as the template. */
14662 }
14663 }
14665 /* Make a new template decl. It will be similar to the
14666 original, but will record the current template arguments.
14667 We also create a new function declaration, which is just
14668 like the old one, but points to this new template, rather
14669 than the old one. */
14674 // Build new template info linking to the original template decl.
14676 {
14679 }
14680 else
14683 /* The template parameters for this new template are all the
14684 template parameters for the old template, except the
14685 outermost level of parameters. */
14688 = current_template_parms
14689 = (lambda_tparms
14690 ? lambda_tparms
14692 complain));
14699 else
14700 {
14702 {
14705 }
14709 else
14711 }
14717 {
14718 /* For a partial specialization, we need to keep pointing to
14719 the primary template. */
14721 {
14724 }
14728 }
14730 {
14733 }
14734 else
14735 {
14738 }
14745 {
14746 /* Propagate module information from the decl. */
14749 /* If this is a constrained template, the above tsubst of
14750 inner can find the unconstrained template, which may have
14751 come from an import. This is ok, because we don't
14752 register this instantiation (see below). */
14754 || (TEMPLATE_PARMS_CONSTRAINTS
14756 }
14765 /* Record this non-type partial instantiation. */
14771 }
14773 /* True if FN is the op() for a lambda in an uninstantiated template. */
14775 bool
14777 {
14782 }
14784 /* True if FN is the substitution (via tsubst_lambda_expr) of a function for
14785 which the above is true. */
14787 bool
14789 {
14795 }
14797 /* Return the LAMBDA_EXPR from which T was ultimately regenerated.
14798 If T is not a regenerated LAMBDA_EXPR, return T. */
14800 tree
14802 {
14806 }
14808 /* Return the set of template arguments used to regenerate the lambda T
14809 from its most general lambda. */
14811 tree
14813 {
14819 else
14821 }
14823 /* We're instantiating a variable from template function TCTX. Return the
14824 corresponding current enclosing scope. We can match them up using
14825 DECL_SOURCE_LOCATION because lambdas only ever have one source location, and
14826 the DECL_SOURCE_LOCATION for a function instantiation is updated to match
14827 the template definition in regenerate_decl_from_template. */
14829 static tree
14831 {
14834 /* We shouldn't ever need to do this for other artificial functions. */
14841 }
14843 /* Substitute the ARGS into the T, which is a _DECL. Return the
14844 result of the substitution. Issue error and warning messages under
14845 control of COMPLAIN. */
14847 static tree
14849 {
14850 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
14851 location_t saved_loc;
14856 /* Set the filename and linenumber to improve error-reporting. */
14861 {
14873 {
14881 {
14882 /* If there is a local specialization that isn't a
14883 parameter pack, it means that we're doing a "simple"
14884 substitution from inside tsubst_pack_expansion. Just
14885 return the local specialization (which will be a single
14886 parm). */
14893 /* Expand the TYPE_PACK_EXPANSION that provides the types for
14894 the parameters in this function parameter pack. */
14898 {
14901 /* Zero-length parameter packs are boring. Just substitute
14902 into the chain. */
14906 }
14907 else
14908 {
14909 /* All we did was update the type. Make a note of that. */
14912 }
14913 }
14915 /* Loop through all of the parameters we'll build. When T is
14916 a function parameter pack, LEN is the number of expanded
14917 types in EXPANDED_TYPES; otherwise, LEN is 1. */
14920 {
14927 /* We're on the Ith parameter of the function parameter
14928 pack. */
14929 {
14930 /* Get the Ith type. */
14933 /* Rename the parameter to include the index. */
14936 }
14938 /* We're dealing with a normal parameter. */
14946 {
14949 else
14952 }
14963 /* Keep track of the first new parameter we
14964 generate. That's what will be returned to the
14965 caller. */
14969 /* Build a proper chain of parameters when substituting
14970 into a function parameter pack. */
14973 }
14975 /* If cp_unevaluated_operand is set, we're just looking for a
14976 single dummy parameter, so don't keep going. */
14981 /* FIRST_R contains the start of the chain we've built. */
14983 }
14987 {
14994 {
14995 /* This field is a lambda capture pack. Return a TREE_VEC of
14996 the expanded fields to instantiate_class_template_1. */
15000 {
15003 }
15004 else
15005 {
15006 /* All we did was update the type. Make a note of that. */
15009 }
15010 }
15013 {
15016 {
15020 }
15030 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
15031 number of bits. */
15036 {
15037 /* Set up DECL_TEMPLATE_INFO so that we can get at the
15038 NSDMI in perform_member_init. Still set DECL_INITIAL
15039 so that we know there is one. */
15044 }
15045 /* We don't have to set DECL_CONTEXT here; it is set by
15046 finish_member_declaration. */
15055 }
15059 }
15063 /* We reach here only for member using decls. We also need to check
15064 uses_template_parms because DECL_DEPENDENT_P is not set for a
15065 using-declaration that designates a member of the current
15066 instantiation (c++/53549). */
15069 {
15070 /* True iff this using-decl was written as a pack expansion
15071 (and a pack appeared in its scope or name). If a pack
15072 appeared in both, we expand the packs separately and
15073 manually merge them. */
15078 {
15081 in_decl);
15083 }
15084 else
15090 {
15094 {
15097 }
15101 }
15102 else
15110 {
15112 {
15117 }
15119 }
15127 {
15136 {
15139 }
15143 }
15147 }
15148 else
15149 {
15152 }
15157 {
15168 {
15169 /* If this is the canonical decl, we don't have to
15170 mess with instantiations, and often we can't (for
15171 typename, template type parms and such). Note that
15172 TYPE_NAME is not correct for the above test if
15173 we've copied the type for a typedef. */
15179 }
15181 /* Check to see if we already have the specialization we
15182 need. */
15188 {
15191 {
15193 complain,
15196 /* The context and type of an injected-class-name are
15197 the same, so we don't need to substitute both. */
15199 /* If CTX is unchanged, then T is in fact the
15200 specialization we want. That situation occurs when
15201 referencing a static data member within in its own
15202 class. We can use pointer equality, rather than
15203 same_type_p, because DECL_CONTEXT is always
15204 canonical... */
15206 /* ... unless T is a member template; in which
15207 case our caller can be willing to create a
15208 specialization of that template represented
15209 by T. */
15213 }
15216 {
15223 /* We're fully specializing a template declaration, so
15224 we need to coerce the innermost arguments corresponding to
15225 the template. */
15226 argvec = (coerce_template_parms
15233 }
15234 }
15235 else
15236 {
15238 /* Subsequent calls to pushdecl will fill this in. */
15240 /* A local variable. */
15242 /* Unless this is a reference to a static variable from an
15243 enclosing function, in which case we need to fill it in now. */
15245 {
15249 }
15251 }
15252 /* If we already have the specialization we need, there is
15253 nothing more to do. */
15255 {
15258 }
15260 /* Create a new node for the specialization we need. */
15262 {
15265 else
15275 /* Substituting the type might have recursively instantiated this
15276 same alias (c++/86171). */
15279 {
15282 }
15283 }
15286 {
15292 {
15293 /* It may seem that this case cannot occur, since:
15295 typedef void f();
15296 void g() { f x; }
15298 declares a function, not a variable. However:
15300 typedef void f();
15301 template <typename T> void g() { T t; }
15302 template void g<f>();
15304 is an attempt to declare a variable with function
15305 type. */
15307 /* R is not yet sufficiently initialized, so we
15308 just use its name. */
15311 }
15313 /* Wait until cp_finish_decl to set this again, to handle
15314 circular dependency (template/instantiate6.C). */
15319 {
15321 /* If the DECL_VALUE_EXPR is converted to the declared type,
15322 preserve the identity so that gimplify_type_sizes works. */
15328 {
15331 }
15340 else
15344 }
15348 }
15354 /* Clear out the mangled name and RTL for the instantiation. */
15360 /* The initializer must not be expanded until it is required;
15361 see [temp.inst]. */
15365 {
15371 /* Possibly limit visibility based on template args. */
15374 {
15378 }
15380 }
15383 {
15384 /* A static data member declaration is always marked
15385 external when it is declared in-class, even if an
15386 initializer is present. We mimic the non-template
15387 processing here. */
15396 }
15397 else
15398 {
15403 }
15412 /* Preserve a typedef that names a type. */
15414 {
15418 /* common_handle_aligned_attribute doesn't apply the alignment
15419 to DECL_ORIGINAL_TYPE. */
15423 }
15426 }
15431 }
15432 #undef RETURN
15434 out:
15435 /* Restore the file and line information. */
15439 }
15441 /* Substitute into the complete parameter type list PARMS. */
15443 tree
15445 tree args,
15446 tsubst_flags_t complain,
15447 tree in_decl)
15448 {
15450 }
15452 /* Substitute into the ARG_TYPES of a function type.
15453 If END is a TREE_CHAIN, leave it and any following types
15454 un-substituted. */
15456 static tree
15458 tree args,
15459 tree end,
15460 tsubst_flags_t complain,
15461 tree in_decl)
15462 {
15471 {
15472 /* For a pack expansion, perform substitution on the
15473 entire expression. Later on, we'll handle the arguments
15474 one-by-one. */
15479 /* So that we'll spin through the parameters, one by one. */
15481 else
15482 {
15483 /* We only partially substituted into the parameter
15484 pack. Our type is TYPE_PACK_EXPANSION. */
15487 }
15488 }
15489 else
15492 /* Check if a substituted type is erroneous before substituting into
15493 the rest of the chain. */
15495 {
15502 {
15504 {
15508 }
15510 }
15511 }
15513 /* We do not substitute into default arguments here. The standard
15514 mandates that they be instantiated only when needed, which is
15515 done in build_over_call. */
15518 /* Except that we do substitute default arguments under tsubst_lambda_expr,
15519 since the new op() won't have any associated template arguments for us
15520 to refer to later. */
15532 {
15536 /* Do array-to-pointer, function-to-pointer conversion, and ignore
15537 top-level qualifiers as required. */
15541 {
15542 /* We've instantiated a template before its default arguments
15543 have been parsed. This can happen for a nested template
15544 class, and is not an error unless we require the default
15545 argument in a call of this function. */
15546 remaining_arg_types
15549 remaining_arg_types);
15550 }
15551 else
15552 remaining_arg_types
15554 }
15557 }
15559 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
15560 *not* handle the exception-specification for FNTYPE, because the
15561 initial substitution of explicitly provided template parameters
15562 during argument deduction forbids substitution into the
15563 exception-specification:
15565 [temp.deduct]
15567 All references in the function type of the function template to the
15568 corresponding template parameters are replaced by the specified tem-
15569 plate argument values. If a substitution in a template parameter or
15570 in the function type of the function template results in an invalid
15571 type, type deduction fails. [Note: The equivalent substitution in
15572 exception specifications is done only when the function is instanti-
15573 ated, at which point a program is ill-formed if the substitution
15574 results in an invalid type.] */
15576 static tree
15578 tree args,
15579 tsubst_flags_t complain,
15580 tree in_decl)
15581 {
15582 tree return_type;
15585 /* The TYPE_CONTEXT is not used for function/method types. */
15588 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
15589 failure. */
15593 {
15594 /* Substitute the argument types. */
15606 {
15607 /* DR 1207: 'this' is in scope in the trailing return type. */
15609 }
15611 /* Substitute the return type. */
15615 {
15618 }
15619 }
15620 else
15621 /* Substitute the return type. */
15626 /* DR 486 clarifies that creation of a function type with an
15627 invalid return type is a deduction failure. */
15630 {
15632 {
15635 else
15637 }
15639 }
15642 {
15643 /* Substitute the argument types. */
15648 }
15650 /* Construct a new type node and return it. */
15653 }
15655 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
15656 ARGS into that specification, and return the substituted
15657 specification. If there is no specification, return NULL_TREE. */
15659 static tree
15661 tree args,
15662 tsubst_flags_t complain,
15663 tree in_decl,
15665 {
15666 tree specs;
15667 tree new_specs;
15672 {
15673 /* A noexcept-specifier. */
15678 {
15679 /* Defer instantiation of noexcept-specifiers to avoid
15680 excessive instantiations (c++/49107). */
15683 {
15684 /* We already partially instantiated this member template,
15685 so combine the new args with the old. */
15690 }
15691 else
15692 {
15695 }
15696 }
15697 else
15698 {
15700 {
15702 args);
15704 }
15706 }
15708 /* We've instantiated a template before a noexcept-specifier
15709 contained therein has been parsed. This can happen for
15710 a nested template class:
15712 struct S {
15713 template<typename> struct B { B() noexcept(...); };
15714 struct A : B<int> { ... use B() ... };
15715 };
15717 where completing B<int> will trigger instantiating the
15718 noexcept, even though we only parse it at the end of S. */
15720 {
15723 }
15724 }
15726 {
15729 else
15731 {
15732 tree spec;
15737 {
15738 /* Expand the pack expansion type. */
15741 in_decl);
15747 else
15748 {
15749 /* We're substituting into a member template, so
15750 we got a TYPE_PACK_EXPANSION back. Add that
15751 expansion and move on. */
15755 expanded_specs,
15756 complain);
15759 }
15760 }
15763 {
15766 else
15771 complain);
15772 }
15775 }
15776 }
15778 }
15780 /* Substitute through a TREE_LIST of types or expressions, handling pack
15781 expansions. */
15783 tree
15785 {
15792 ;
15794 {
15798 }
15801 else
15809 ;
15811 {
15815 }
15818 else
15825 ;
15830 else
15841 /* Determine the number of arguments. */
15843 {
15846 }
15849 else
15853 {
15861 else
15863 }
15866 }
15868 /* Take the tree structure T and replace template parameters used
15869 therein with the argument vector ARGS. IN_DECL is an associated
15870 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
15871 Issue error and warning messages under control of COMPLAIN. Note
15872 that we must be relatively non-tolerant of extensions here, in
15873 order to preserve conformance; if we allow substitutions that
15874 should not be allowed, we may allow argument deductions that should
15875 not succeed, and therefore report ambiguous overload situations
15876 where there are none. In theory, we could allow the substitution,
15877 but indicate that it should have failed, and allow our caller to
15878 make sure that the right thing happens, but we don't try to do this
15879 yet.
15881 This function is used for dealing with types, decls and the like;
15882 for expressions, use tsubst_expr or tsubst_copy. */
15884 tree
15886 {
15921 /* Reuse typedefs. We need to do this to handle dependent attributes,
15922 such as attribute aligned. */
15925 {
15929 {
15930 /* DECL represents an alias template and we want to
15931 instantiate it. */
15935 }
15939 {
15943 }
15948 else
15949 /* The typedef is from a non-template context. */
15953 {
15955 r = cp_build_qualified_type
15959 }
15960 else
15961 {
15962 /* We don't have an instantiation yet, so drop the typedef. */
15967 }
15968 }
15985 {
15989 /* Fall through. */
16015 {
16020 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
16021 needed. */
16027 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
16028 with TREE_SIDE_EFFECTS that indicates this is not an integral
16029 constant expression. */
16032 {
16035 }
16038 }
16042 {
16050 else
16052 }
16053 /* Fall through. */
16057 {
16071 {
16074 /* See through ARGUMENT_PACK_SELECT arguments. */
16077 }
16082 {
16084 /* If ARG is an argument pack, we don't actually want to
16085 perform a substitution here, because substitutions
16086 for argument packs are only done
16087 element-by-element. We can get to this point when
16088 substituting the type of a non-type template
16089 parameter pack, when that type actually contains
16090 template parameter packs from an outer template, e.g.,
16092 template<typename... Types> struct A {
16093 template<Types... Values> struct B { };
16094 }; */
16098 {
16101 /* When building concept checks for the purpose of
16102 deducing placeholders, we can end up with wildcards
16103 where types are expected. Adjust this to the deduced
16104 value. */
16112 return cp_build_qualified_type
16114 }
16116 {
16117 /* We are processing a type constructed from a
16118 template template parameter. */
16129 /* Consider this code:
16131 template <template <class> class Template>
16132 struct Internal {
16133 template <class Arg> using Bind = Template<Arg>;
16134 };
16136 template <template <class> class Template, class Arg>
16137 using Instantiate = Template<Arg>; //#0
16139 template <template <class> class Template,
16140 class Argument>
16141 using Bind =
16142 Instantiate<Internal<Template>::template Bind,
16143 Argument>; //#1
16145 When #1 is parsed, the
16146 BOUND_TEMPLATE_TEMPLATE_PARM representing the
16147 parameter `Template' in #0 matches the
16148 UNBOUND_CLASS_TEMPLATE representing the argument
16149 `Internal<Template>::template Bind'; We then want
16150 to assemble the type `Bind<Argument>' that can't
16151 be fully created right now, because
16152 `Internal<Template>' not being complete, the Bind
16153 template cannot be looked up in that context. So
16154 we need to "store" `Bind<Argument>' for later
16155 when the context of Bind becomes complete. Let's
16156 store that in a TYPENAME_TYPE. */
16160 argvec),
16161 typename_type,
16162 complain);
16164 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
16165 are resolving nested-types in the signature of a
16166 member function templates. Otherwise ARG is a
16167 TEMPLATE_DECL and is the real template to be
16168 instantiated. */
16176 complain);
16177 return cp_build_qualified_type
16179 }
16182 else
16183 /* TEMPLATE_PARM_INDEX. */
16185 }
16188 /* This can happen during the attempted tsubst'ing in
16189 unify. This means that we don't yet have any information
16190 about the template parameter in question. */
16193 /* Early in template argument deduction substitution, we don't
16194 want to reduce the level of 'auto', or it will be confused
16195 with a normal template parm in subsequent deduction.
16196 Similarly, don't reduce the level of template parameters to
16197 avoid mismatches when deducing their types. */
16201 /* If we get here, we must have been looking at a parm for a
16202 more deeply nested template. Make a new version of this
16203 template parameter, but with a lower level. */
16206 {
16211 {
16214 }
16221 /* Cache the simple case of lowering a type parameter. */
16223 else
16224 {
16236 /* Propagate constraints on placeholders since they are
16237 only instantiated during satisfaction. */
16242 else
16244 }
16252 {
16254 /* We might need to substitute into the types of non-type
16255 template parameters. This also lowers the level of
16256 the ttp appropriately. */
16269 }
16272 /* OK, now substitute the type of the non-type parameter. We
16273 couldn't do it earlier because it might be an auto parameter,
16274 and we wouldn't need to if we had an argument. */
16283 }
16286 }
16292 /* We should never be tsubsting a binfo. */
16296 /* A vector of template arguments. */
16302 {
16306 /* [temp.deduct]
16308 Type deduction may fail for any of the following
16309 reasons:
16311 -- Attempting to create a pointer to reference type.
16312 -- Attempting to create a reference to a reference type or
16313 a reference to void.
16315 Core issue 106 says that creating a reference to a reference
16316 during instantiation is no longer a cause for failure. We
16317 only enforce this check in strict C++98 mode. */
16321 {
16324 /* We keep track of the last time we issued this error
16325 message to avoid spewing a ton of messages during a
16326 single bad template instantiation. */
16329 {
16334 else
16337 }
16340 }
16344 {
16346 {
16349 type);
16350 else
16352 type);
16353 }
16355 }
16357 {
16361 }
16363 /* In C++0x, during template argument substitution, when there is an
16364 attempt to create a reference to a reference type, reference
16365 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
16367 "If a template-argument for a template-parameter T names a type
16368 that is a reference to a type A, an attempt to create the type
16369 'lvalue reference to cv T' creates the type 'lvalue reference to
16370 A,' while an attempt to create the type type rvalue reference to
16371 cv T' creates the type T"
16372 */
16373 r = cp_build_reference_type
16376 else
16381 /* Will this ever be needed for TYPE_..._TO values? */
16385 }
16387 {
16390 {
16391 /* [temp.deduct]
16393 Type deduction may fail for any of the following
16394 reasons:
16396 -- Attempting to create "pointer to member of T" when T
16397 is not a class type. */
16401 }
16403 {
16407 }
16409 {
16413 }
16416 {
16417 /* The type of the implicit object parameter gets its
16418 cv-qualifiers from the FUNCTION_TYPE. */
16419 tree memptr;
16420 tree method_type
16425 complain);
16426 }
16427 else
16430 complain);
16431 }
16434 {
16435 tree fntype;
16436 tree specs;
16441 /* Substitute the exception specification. */
16449 }
16451 {
16456 /* As an optimization, we avoid regenerating the array type if
16457 it will obviously be the same as T. */
16461 /* These checks should match the ones in create_array_type_for_decl.
16463 [temp.deduct]
16465 The deduction may fail for any of the following reasons:
16467 -- Attempting to create an array with an element type that
16468 is void, a function type, or a reference type, or [DR337]
16469 an abstract class type. */
16475 {
16479 }
16492 {
16495 }
16498 }
16501 {
16504 {
16507 in_decl);
16512 {
16517 }
16519 }
16520 else
16533 {
16537 }
16539 {
16540 /* Normally, make_typename_type does not require that the CTX
16541 have complete type in order to allow things like:
16543 template <class T> struct S { typename S<T>::X Y; };
16545 But, such constructs have already been resolved by this
16546 point, so here CTX really should have complete type, unless
16547 it's a partial instantiation. */
16550 }
16552 /* FIXME: TYPENAME_IS_CLASS_P conflates 'class' vs 'struct' vs 'union'
16553 tags. TYPENAME_TYPE should probably remember the exact tag that
16554 was written. */
16555 enum tag_types tag_type
16565 {
16568 }
16571 {
16573 {
16577 else
16579 }
16581 {
16585 else
16587 }
16588 }
16590 return cp_build_qualified_type
16592 }
16595 {
16607 }
16610 {
16611 tree type;
16625 complain);
16626 }
16629 {
16630 tree type;
16647 else
16648 {
16652 /* In a template ~id could be either a complement expression
16653 or an unqualified-id naming a destructor; if instantiating
16654 it produces an expression, it's not an id-expression or
16655 member access. */
16658 }
16663 }
16666 {
16670 else
16677 }
16696 /* We should use one of the expression tsubsts for these codes. */
16702 }
16703 }
16705 /* Convenience wrapper over tsubst for substituting into the LHS
16706 of the :: scope resolution operator. */
16708 static tree
16710 {
16713 }
16715 /* OLDFNS is a lookup set of member functions from some class template, and
16716 NEWFNS is a lookup set of member functions from NEWTYPE, a specialization
16717 of that class template. Return the subset of NEWFNS which are
16718 specializations of a function from OLDFNS. */
16720 static tree
16722 {
16723 /* Record all member functions from the old lookup set OLDFNS into
16724 VISIBLE_SET. */
16728 {
16730 {
16731 /* Imprecisely handle dependent using-decl by keeping all members
16732 in the new lookup set that are defined in a base class, i.e.
16733 members that could plausibly have been introduced by this
16734 dependent using-decl.
16735 FIXME: Track which members are introduced by a dependent
16736 using-decl precisely, perhaps by performing another lookup
16737 from the substituted USING_DECL_SCOPE. */
16740 }
16741 else
16743 }
16745 /* Returns true iff (a less specialized version of) FN appeared in
16746 the old lookup set OLDFNS. */
16749 /* FN is a member function from a base class, introduced via a
16750 using-decl; if it might have been introduced by a dependent
16751 using-decl then just conservatively keep it, otherwise look
16752 in the old lookup set for FN exactly. */
16755 /* FN is a member function template from the current class;
16756 look in the old lookup set for the TEMPLATE_DECL from which
16757 it was specialized. */
16759 else
16760 /* FN is a non-template member function from the current class;
16761 look in the old lookup set for the FUNCTION_DECL from which
16762 it was specialized. */
16765 };
16770 {
16773 }
16777 /* Filter out from NEWFNS the member functions that weren't
16778 previously visible according to OLDFNS. */
16783 {
16785 filtered_size++;
16786 }
16792 }
16794 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
16795 expression on the left-hand side of the "." or "->" operator. We
16796 only do the lookup if we had a dependent BASELINK. Otherwise we
16797 adjust it onto the instantiated heirarchy. */
16799 static tree
16802 {
16814 {
16821 }
16829 {
16834 /* See maybe_dependent_member_ref. */
16836 {
16839 template_args);
16842 }
16845 /* Treat as-if non-dependent below. */
16850 complain);
16852 {
16853 /* Filter out from the new lookup set those functions which didn't
16854 appear in the original lookup set (in a less specialized form).
16855 This is needed to preserve the consistency of member lookup
16856 performed in an incomplete-class context, within which
16857 later-declared members ought to remain invisible. */
16860 binfo_type);
16862 }
16865 {
16871 }
16874 }
16875 else
16876 {
16877 /* We're going to overwrite pieces below, make a duplicate. */
16881 {
16882 /* The decl we found was from non-dependent scope, but we still need
16883 to update the binfos for the instantiated qualifying_scope. */
16887 }
16888 }
16890 /* If lookup found a single function, mark it as used at this point.
16891 (If lookup found multiple functions the one selected later by
16892 overload resolution will be marked as used at that point.) */
16894 {
16900 /* We might have instantiated an auto function. */
16902 }
16905 {
16906 /* Add back the template arguments, if present. */
16911 /* Update the conversion operator type. */
16913 }
16919 {
16921 qualifying_scope,
16922 object_type);
16924 /* We need to call adjust_result_of_qualified_name_lookup in case the
16925 destructor names a base class, but we unset BASELINK_QUALIFIED_P
16926 so that we still get virtual function binding. */
16928 }
16931 }
16933 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
16934 true if the qualified-id will be a postfix-expression in-and-of
16935 itself; false if more of the postfix-expression follows the
16936 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
16937 of "&". */
16939 static tree
16943 {
16944 tree expr;
16945 tree scope;
16946 tree name;
16948 tree template_args;
16953 /* Figure out what name to look up. */
16956 {
16965 }
16966 else
16967 {
16970 }
16972 /* Substitute into the qualifying scope. When there are no ARGS, we
16973 are just trying to simplify a non-dependent expression. In that
16974 case the qualifying scope may be dependent, and, in any case,
16975 substituting will not help. */
16978 {
16981 }
16982 else
16986 {
16988 /* We built one in tsubst_baselink. */
16990 else
16991 {
16994 template_args);
16996 QUALIFIED_NAME_IS_TEMPLATE
16998 }
17001 }
17004 {
17006 {
17007 /* A BIT_NOT_EXPR is used to represent a destructor. */
17009 {
17013 }
17014 else
17017 }
17018 else
17022 {
17024 {
17028 }
17030 }
17031 }
17034 {
17038 /* Remember that there was a reference to this entity. */
17041 }
17044 {
17050 }
17053 {
17054 /* We may be repeating a check already done during parsing, but
17055 if it was well-formed and passed then, it will pass again
17056 now, and if it didn't, we wouldn't have got here. The case
17057 we want to catch is when we couldn't tell then, and can now,
17058 namely when templ prior to substitution was an
17059 identifier. */
17065 complain);
17066 else
17068 }
17074 {
17075 expr = (adjust_result_of_qualified_name_lookup
17077 expr = (finish_qualified_id_expr
17081 }
17083 /* Expressions do not generally have reference type. */
17085 /* However, if we're about to form a pointer-to-member, we just
17086 want the referenced member referenced. */
17096 }
17098 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
17099 initializer, DECL is the substituted VAR_DECL. Other arguments are as
17100 for tsubst. */
17102 static tree
17105 {
17114 {
17116 {
17118 {
17123 }
17124 }
17126 {
17127 /* If we had an initializer but it
17128 instantiated to nothing,
17129 value-initialize the object. This will
17130 only occur when the initializer was a
17131 pack expansion where the parameter packs
17132 used in that expansion were of length
17133 zero. */
17139 }
17140 }
17143 }
17145 /* If T is a reference to a dependent member of the current instantiation C and
17146 we are trying to refer to that member in a partial instantiation of C,
17147 return a SCOPE_REF; otherwise, return NULL_TREE.
17149 This can happen when forming a C++17 deduction guide, as in PR96199. */
17151 static tree
17153 tree in_decl)
17154 {
17171 {
17180 complain);
17181 }
17186 {
17192 }
17195 {
17198 /* The TYPE_DECL for a typename has DECL_CONTEXT of the typename
17199 scope, but it doesn't need to be rewritten again. */
17203 }
17207 else
17210 }
17212 /* Like tsubst, but deals with expressions. This function just replaces
17213 template parms; to finish processing the resultant expression, use
17214 tsubst_copy_and_build or tsubst_expr. */
17216 static tree
17218 {
17220 tree r;
17234 {
17239 {
17240 /* We get here for a use of 'this' in an NSDMI. */
17244 /* This can happen for a parameter name used later in a function
17245 declaration (such as in a late-specified return type). Just
17246 make a dummy decl, since it's only used for its type. */
17249 /* Give it the template pattern as its context; its true context
17250 hasn't been instantiated yet and this is good enough for
17251 mangling. */
17253 }
17262 {
17263 tree enum_type;
17264 tree v;
17271 /* Unfortunately, we cannot just call lookup_name here.
17272 Consider:
17274 template <int I> int f() {
17275 enum E { a = I };
17276 struct S { void g() { E e = a; } };
17277 };
17279 When we instantiate f<7>::S::g(), say, lookup_name is not
17280 clever enough to find f<7>::a. */
17281 enum_type
17291 /* We didn't find the name. That should never happen; if
17292 name-lookup found it during preliminary parsing, we
17293 should find it again here during instantiation. */
17295 }
17300 {
17301 tree ctx;
17306 {
17309 {
17313 }
17315 }
17316 }
17325 {
17326 /* Local specialization will usually have been created when
17327 we instantiated the DECL_EXPR_DECL. */
17330 {
17331 /* We're in a generic lambda referencing a local extern
17332 from an outer block-scope of a non-template. */
17335 }
17336 }
17339 {
17342 {
17343 /* First try name lookup to find the instantiation. */
17346 {
17348 {
17349 /* During error-recovery we may find a non-variable,
17350 even an OVERLOAD: just bail out and avoid ICEs and
17351 duplicate diagnostics (c++/62207). */
17354 }
17356 {
17357 /* Make sure the one we found is the one we want. */
17361 }
17362 }
17366 else
17367 {
17368 /* This can happen for a variable used in a
17369 late-specified return type of a local lambda, or for a
17370 local static or constant. Building a new VAR_DECL
17371 should be OK in all those cases. */
17374 /* Avoid infinite recursion (79640). */
17377 {
17378 /* We can't call cp_finish_decl, so handle the
17379 initializer by hand. */
17394 }
17396 || processing_contract_condition
17403 }
17404 /* Remember this for subsequent uses. */
17407 }
17410 }
17411 else
17435 {
17436 /* Template template argument like the following example need
17437 special treatment:
17439 template <template <class> class TT> struct C {};
17440 template <class T> struct D {
17441 template <class U> struct E {};
17442 C<E> c; // #1
17443 };
17444 D<int> d; // #2
17446 We are processing the template argument `E' in #1 for
17447 the template instantiation #2. Originally, `E' is a
17448 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
17449 have to substitute this with one having context `D<int>'. */
17454 }
17455 else
17456 /* Ordinary template template argument. */
17461 {
17462 /* Handle location wrappers by substituting the wrapped node
17463 first, *then* reusing the resulting type. Doing the type
17464 first ensures that we handle template parameters and
17465 parameter pack expansions. */
17467 {
17471 }
17473 /* force_paren_expr can also create a VIEW_CONVERT_EXPR. */
17475 {
17480 }
17481 /* We shouldn't see any other uses of these in templates
17482 (tsubst_copy_and_build handles C++20 tparm object wrappers). */
17484 }
17492 CASE_CONVERT:
17493 {
17500 }
17503 {
17509 }
17514 {
17523 /* We only want to compute the number of arguments. */
17526 else
17533 {
17535 /* Set TREE_USED for the benefit of -Wunused. */
17539 }
17547 {
17552 else
17560 else
17565 }
17566 else
17568 }
17570 {
17578 }
17579 /* Fall through */
17595 {
17601 /* For addresses of immediate functions ensure we have EXPR_LOCATION
17602 set for possible later diagnostics. */
17609 }
17612 {
17616 {
17619 }
17621 }
17624 {
17625 tree object;
17626 tree name;
17631 {
17635 }
17638 {
17648 }
17653 in_decl);
17654 else
17657 }
17693 {
17697 }
17700 {
17705 }
17708 {
17712 }
17715 {
17723 }
17729 {
17736 }
17739 {
17746 }
17749 {
17756 }
17759 {
17760 /* Substituted template arguments */
17770 else
17772 }
17775 {
17795 }
17803 /* Fall through. */
17806 {
17809 }
17810 else
17814 /* This is handled by tsubst_copy_and_build. */
17818 {
17822 }
17825 /* We shouldn't have built any of these during initial template
17826 generation. Instead, they should be built during instantiation
17827 in response to the saved STMT_IS_FULL_EXPR_P setting. */
17831 {
17841 }
17859 {
17860 /* Instantiate any typedefs in the type. */
17865 }
17868 {
17872 {
17875 }
17877 }
17880 /* These can sometimes show up in a partial instantiation, but never
17881 involve template parms. */
17897 /* ??? There's no point in copying it for now, but maybe some
17898 day it will contain more information, such as a pointer back
17899 to the containing function, inlined copy or so. */
17906 /* We shouldn't get here, but keep going if !flag_checking. */
17910 }
17911 }
17913 /* Helper function for tsubst_omp_clauses, used for instantiation of
17914 OMP_CLAUSE_DECL of clauses. */
17916 static tree
17919 {
17923 /* Handle OpenMP iterators. */
17927 {
17928 tree ret;
17931 else
17932 {
17936 {
17950 }
17954 }
17958 }
17960 /* Handle an OpenMP array section represented as a TREE_LIST (or
17961 OMP_CLAUSE_DOACROSS_KIND). An OMP_CLAUSE_DOACROSS (with a depend
17962 kind of OMP_CLAUSE_DOACROSS_SINK) can also be represented as a
17963 TREE_LIST. We can handle it exactly the same as an array section
17964 (purpose, value, and a chain), even though the nomenclature
17965 (low_bound, length, etc) is different. */
17967 {
17968 tree low_bound
17981 }
17983 /* Undo convert_from_reference tsubst_expr could have called. */
17989 }
17991 /* Like tsubst_copy, but specifically for OpenMP clauses. */
17993 static tree
17996 {
18002 {
18008 {
18011 {
18017 }
18018 /* FALLTHRU */
18048 /* FALLTHRU */
18081 {
18084 {
18091 }
18092 else
18094 }
18121 {
18124 }
18129 else
18160 }
18163 {
18180 /* tsubst_expr on SCOPE_REF results in returning
18181 finish_non_static_data_member result. Undo that here. */
18185 {
18190 {
18194 CASE_CONVERT:
18203 /* FALLTHRU */
18207 }
18208 }
18214 {
18217 {
18220 }
18221 }
18225 }
18226 }
18230 {
18235 {
18238 }
18239 }
18241 }
18243 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
18245 static tree
18247 tree in_decl)
18248 {
18249 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
18267 {
18270 else
18271 {
18275 }
18276 }
18281 #undef RECUR
18282 }
18284 /* Used to temporarily communicate the list of #pragma omp parallel
18285 clauses to #pragma omp for instantiation if they are combined
18286 together. */
18293 /* Substitute one OMP_FOR iterator. */
18295 static bool
18299 {
18300 #define RECUR(NODE) \
18301 tsubst_expr ((NODE), args, complain, in_decl)
18313 {
18316 {
18321 {
18331 else
18333 {
18335 {
18341 }
18344 }
18345 }
18346 }
18350 }
18352 {
18353 /* We need to jump through some hoops to handle declarations in the
18354 init-statement, since we might need to handle auto deduction,
18355 but we need to keep control of initialization. */
18359 }
18360 else
18361 {
18363 {
18366 {
18370 {
18374 CASE_CONVERT:
18382 {
18385 }
18386 /* FALLTHRU */
18390 }
18391 }
18392 }
18393 else
18395 }
18397 {
18403 }
18404 else
18408 {
18414 NULL_TREE);
18415 else
18417 }
18420 {
18427 {
18432 }
18435 }
18445 {
18447 {
18448 /* Declare the variable, but don't let that initialize it. */
18453 }
18456 {
18460 {
18469 }
18470 else
18474 {
18479 }
18480 else
18484 }
18490 }
18493 {
18494 /* Declare and initialize the variable. */
18497 }
18499 {
18504 {
18506 {
18512 {
18515 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
18520 }
18523 {
18525 decl);
18527 }
18530 {
18532 decl);
18534 }
18535 else
18537 }
18540 }
18542 {
18545 ? OMP_CLAUSE_LASTPRIVATE
18550 {
18553 }
18554 }
18555 }
18558 {
18562 }
18563 else
18567 {
18578 {
18586 }
18587 else
18593 {
18599 }
18603 {
18611 }
18612 else
18618 }
18627 #undef RECUR
18628 }
18630 /* Helper function of tsubst_expr, find OMP_TEAMS inside
18631 of OMP_TARGET's body. */
18633 static tree
18635 {
18638 {
18647 }
18649 }
18651 /* Helper function for tsubst_expr. For decomposition declaration
18652 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
18653 also the corresponding decls representing the identifiers
18654 of the decomposition declaration. Return DECL if successful
18655 or error_mark_node otherwise, set *FIRST to the first decl
18656 in the list chained through DECL_CHAIN and *CNT to the number
18657 of such decls. */
18659 static tree
18663 {
18668 decl2
18673 {
18675 {
18678 }
18690 else
18691 {
18695 }
18702 {
18705 }
18706 else
18708 }
18711 }
18713 /* Return the proper local_specialization for init-capture pack DECL. */
18715 static tree
18717 {
18718 /* We handle normal pack captures by forwarding to the specialization of the
18719 captured parameter. We can't do that for pack init-captures; we need them
18720 to have their own local_specialization. We created the individual
18721 VAR_DECLs (if any) under build_capture_proxy, and we need to collect them
18722 when we process the DECL_EXPR for the pack init-capture in the template.
18723 So, how do we find them? We don't know the capture proxy pack when
18724 building the individual resulting proxies, and we don't know the
18725 individual proxies when instantiating the pack. What we have in common is
18726 the FIELD_DECL.
18728 So...when we instantiate the FIELD_DECL, we stick the result in
18729 local_specializations. Then at the DECL_EXPR we look up that result, see
18730 how many elements it has, synthesize the names, and look them up. */
18744 {
18749 }
18751 {
18756 else
18758 }
18760 }
18762 /* T is an operand of a template tree being substituted. Return whether
18763 T is dependent such that we should suppress some warnings that would
18764 make sense if the substituted expression were written directly, like
18765 template <int I> bool f() { return I == 2; }
18766 We don't want to warn when instantiating f that comparing two constants
18767 always has the same value.
18769 This is a more limited concept of dependence than instantiation-dependent;
18770 here we don't care whether substitution could fail. */
18772 static bool
18774 {
18783 }
18785 /* Like tsubst_copy for expressions, etc. but also does semantic
18786 processing. */
18788 tree
18790 {
18791 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
18792 #define RECUR(NODE) \
18793 tsubst_expr ((NODE), args, complain, in_decl)
18796 tree r;
18797 location_t loc;
18809 {
18811 {
18815 }
18844 else
18857 {
18862 }
18866 {
18868 tree init;
18874 {
18877 {
18881 {
18886 }
18888 }
18889 else
18890 {
18891 /* This is a non-dependent using-decl, and we'll have
18892 used the names it found during template parsing. We do
18893 not want to do the lookup again, because we might not
18894 find the things we found then. */
18897 /* We still need to push the bindings so that we can look up
18898 this name later. */
18901 }
18902 }
18905 {
18906 /* We're in tsubst_lambda_expr, we've already inserted a new
18907 capture proxy, so look it up and register it. */
18908 tree inst;
18910 {
18914 }
18916 {
18917 inst = (retrieve_local_specialization
18921 }
18922 else
18927 }
18934 /* Don't copy the old closure; we'll create a new one in
18935 tsubst_lambda_expr. */
18937 else
18938 {
18942 {
18943 /* By marking the declaration as instantiated, we avoid
18944 trying to instantiate it. Since instantiate_decl can't
18945 handle local variables, and since we've already done
18946 all that needs to be done, that's the right thing to
18947 do. */
18952 /* Anonymous aggregates are a special case. */
18955 {
18958 {
18962 }
18964 }
18969 {
18977 }
18978 else
18979 {
19001 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
19007 /* In a non-template function, VLA type declarations are
19008 handled in grokdeclarator; for templates, handle them
19009 now. */
19013 {
19017 asmspec_tree
19021 }
19027 }
19028 }
19029 }
19032 }
19042 {
19046 }
19051 {
19052 /* Construct another range_for, if this is not a final
19053 substitution (for inside a generic lambda of a
19054 template). Otherwise convert to a regular for. */
19056 stmt = (processing_template_decl
19073 {
19079 }
19080 else
19081 {
19087 }
19093 }
19100 {
19104 }
19110 {
19114 }
19126 {
19132 }
19135 {
19136 /* We're partially instantiating a generic lambda, but the condition
19137 of the constexpr if is still dependent. Don't substitute into the
19138 branches now, just remember the template arguments. */
19146 }
19150 {
19155 }
19156 else
19157 {
19165 }
19171 {
19181 }
19189 else
19197 else
19218 {
19224 {
19229 }
19230 }
19234 {
19236 tree label;
19243 }
19249 /* Computed goto's must be tsubst'd into. On the other hand,
19250 non-computed gotos must not be; the identifier in question
19251 will have no binding. */
19253 else
19259 {
19276 }
19281 {
19286 }
19287 else
19288 {
19293 else
19300 else
19306 else
19308 }
19312 {
19316 {
19318 /* Prevent instantiate_decl from trying to instantiate
19319 this variable. We've already done all that needs to be
19320 done. */
19323 }
19328 }
19334 {
19335 /* Local classes are not independent templates; they are
19336 instantiated along with their containing function. And this
19337 way we don't have to deal with pushing out of one local class
19338 to instantiate a member of another local class. */
19339 /* Closures are handled by the LAMBDA_EXPR. */
19343 {
19344 /* This is a partial instantiation, try again when full. */
19347 }
19361 }
19365 {
19366 tree condition;
19377 }
19384 in_decl);
19406 {
19413 }
19429 {
19443 in_decl);
19445 {
19452 }
19463 any_range_for
19470 {
19479 }
19480 else
19485 else
19492 else
19493 {
19501 }
19504 t));
19506 }
19512 /* FALLTHRU */
19522 in_decl);
19524 {
19529 }
19530 else
19531 {
19535 }
19540 {
19542 "%<#pragma omp critical%> with %<hint%> clause requires "
19545 }
19556 {
19559 {
19564 }
19565 else
19566 {
19570 }
19572 }
19573 else
19575 OMP_CLAUSE_DEPEND_INVALID,
19584 ? C_ORT_ACC
19603 {
19606 /* For combined target teams, ensure the num_teams and
19607 thread_limit clause expressions are evaluated on the host,
19608 before entering the target construct. */
19617 {
19620 tf_none);
19627 OMP_CLAUSE_FIRSTPRIVATE);
19631 }
19632 }
19669 {
19673 }
19674 else
19685 /* FALLTHRU */
19703 {
19709 {
19712 }
19714 {
19718 {
19721 }
19726 }
19727 else
19728 {
19731 }
19736 }
19737 else
19738 {
19745 {
19748 }
19751 {
19756 {
19759 }
19761 {
19765 {
19768 }
19773 }
19774 else
19775 {
19778 }
19782 }
19783 else
19784 {
19788 }
19792 }
19796 {
19802 {
19806 {
19811 }
19815 }
19816 else
19817 {
19822 }
19823 }
19827 {
19831 }
19844 /* If the first operand was a statement, we're done with it. */
19849 complain));
19865 }
19868 out:
19871 #undef RECUR
19872 #undef RETURN
19873 }
19875 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
19876 function. For description of the body see comment above
19877 cp_parser_omp_declare_reduction_exprs. */
19879 static void
19881 {
19887 tree_stmt_iterator tsi;
19898 {
19905 /* tsubsting a local var_decl leaves DECL_CONTEXT null, as we
19906 expect to be pushing it. */
19918 }
19920 {
19940 }
19941 }
19943 /* T is a postfix-expression that is not being used in a function
19944 call. Return the substituted version of T. */
19946 static tree
19948 tsubst_flags_t complain,
19949 tree in_decl)
19950 {
19954 else
19958 }
19960 /* Subroutine of tsubst_lambda_expr: add the FIELD/INIT capture pair to the
19961 LAMBDA_EXPR_CAPTURE_LIST passed in LIST. Do deduction for a previously
19962 dependent init-capture. EXPLICIT_P is true if the original list had
19963 explicit captures. */
19965 static void
19967 tsubst_flags_t complain)
19968 {
19970 {
19973 {
19977 }
19984 }
19987 }
19989 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
19990 instantiation context. Instantiating a pack expansion containing a lambda
19991 might result in multiple lambdas all based on the same lambda in the
19992 template. */
19994 tree
19996 {
20011 else
20022 {
20027 else
20039 {
20040 /* For a VLA, simply tsubsting the field type won't work, we need to
20041 go through add_capture again. XXX do we want to do this for all
20042 captures? */
20043 tree name = (get_identifier
20051 }
20058 {
20059 /* Remember these for when we've pushed local_specializations. */
20062 }
20068 {
20077 complain);
20078 }
20079 else
20080 {
20086 }
20087 }
20096 /* If we're pushed into another scope (PR105652), fix it. */
20101 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
20118 {
20121 }
20124 {
20127 }
20131 else
20132 {
20133 /* The body of a lambda-expression is not a subexpression of the
20134 enclosing expression. Parms are to have DECL_CHAIN tsubsted,
20135 which would be skipped if cp_unevaluated_operand. */
20136 cp_evaluated ev;
20138 /* Fix the type of 'this'. */
20142 tree inst = (oldtmpl
20147 {
20150 }
20156 /* Let finish_function set this. */
20162 else
20163 /* Still increment function_depth so that we don't GC in the
20164 middle of an expression. */
20174 /* Now record them for lookup_init_capture_pack. */
20177 {
20181 }
20187 {
20188 /* We might not partially instantiate some parts of the function, so
20189 copy these flags from the original template. */
20195 }
20197 /* [temp.deduct] A lambda-expression appearing in a function type or a
20198 template parameter is not considered part of the immediate context for
20199 the purposes of template argument deduction. */
20204 /* We already have a body block from start_lambda_function, we don't
20205 need another to confuse NRV (91217). */
20216 else
20219 /* The capture list was built up in reverse order; fix that now. */
20226 }
20228 out:
20234 }
20236 /* Subroutine of maybe_fold_fn_template_args. */
20238 static bool
20240 {
20243 {
20249 {
20252 }
20257 {
20261 }
20262 }
20265 }
20267 /* Try to do constant evaluation of any explicit template arguments in FN
20268 before overload resolution, to get any errors only once. Return true iff
20269 we didn't have any problems folding. */
20271 static bool
20273 {
20291 }
20293 /* Helper function for tsubst_copy_and_build CALL_EXPR and ARRAY_REF
20294 handling. */
20296 static void
20299 {
20302 {
20308 else
20309 {
20310 /* Expand the pack expansion and push each entry onto CALL_ARGS. */
20313 {
20318 {
20323 }
20324 }
20325 else
20326 /* A partial substitution. Add one entry. */
20328 }
20329 }
20330 }
20332 /* Like tsubst but deals with expressions and performs semantic
20333 analysis. */
20335 tree
20337 tree args,
20338 tsubst_flags_t complain,
20339 tree in_decl)
20340 {
20341 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
20342 #define RECUR(NODE) \
20343 tsubst_copy_and_build (NODE, args, complain, in_decl)
20346 location_t save_loc;
20355 /* N3276 decltype magic only applies to calls at the top level or on the
20356 right side of a comma. */
20361 {
20364 /* Fall through. */
20366 {
20367 tree decl;
20368 cp_id_kind idk;
20372 {
20375 }
20377 /* Look up the name. */
20380 /* By convention, expressions use ERROR_MARK_NODE to indicate
20381 failure, not NULL_TREE. */
20395 input_location);
20399 {
20403 }
20405 }
20408 {
20409 tree object;
20420 {
20425 }
20428 {
20435 /* If we built a function concept check, return the underlying
20436 template-id. So we can evaluate it as a function call. */
20441 }
20444 {
20446 complain);
20450 }
20453 {
20456 }
20457 else
20467 {
20468 /* C++20 P0846: we can encounter an IDENTIFIER_NODE here when
20469 name lookup found nothing when parsing the template name. */
20472 }
20473 else
20475 }
20478 {
20482 {
20483 /* A type conversion to reference type will be enclosed in
20484 such an indirect ref, but the substitution of the cast
20485 will have also added such an indirect ref. */
20487 }
20488 else
20497 }
20500 {
20504 }
20507 {
20511 {
20516 }
20518 /* We'll pass this to convert_nontype_argument again, we don't need
20519 to actually perform any conversion here. */
20527 flags));
20528 }
20531 {
20537 }
20544 {
20545 tree type;
20559 {
20579 }
20582 }
20585 {
20589 }
20614 {
20621 }
20624 /* convert_like should have created an IMPLICIT_CONV_EXPR. */
20635 else
20637 in_decl);
20672 {
20673 /* If either OP0 or OP1 was value- or type-dependent, suppress
20674 warnings that depend on the range of the types involved. */
20688 tree r = build_x_binary_op
20690 op0,
20692 ? ERROR_MARK
20694 op1,
20696 ? ERROR_MARK
20705 }
20708 {
20716 }
20732 {
20734 releasing_vec index_exp_list;
20736 index_exp_list);
20738 tree r;
20744 else
20749 }
20758 /* Fall through */
20761 {
20762 tree r;
20770 {
20771 /* When there are no ARGS, we are trying to evaluate a
20772 non-dependent expression from the parser. Trying to do
20773 the substitutions may not work. */
20776 }
20777 else
20778 {
20783 else
20787 }
20792 else
20797 {
20799 {
20801 {
20805 }
20806 else
20810 }
20812 }
20814 }
20817 {
20825 }
20839 {
20844 tree r = build_x_modify_expr
20848 /* TREE_NO_WARNING must be set if either the expression was
20849 parenthesized or it uses an operator such as >>= rather
20850 than plain assignment. In the former case, it was already
20851 set and must be copied. In the latter case,
20852 build_x_modify_expr sets it and it must not be reset
20853 here. */
20858 }
20863 /* Remember that there was a reference to this entity. */
20870 {
20875 tree ret;
20882 else
20883 {
20887 }
20889 /* If there was an initializer in the original tree, but it
20890 instantiated to an empty list, then we should pass a
20891 non-NULL empty vector to tell build_new that it was an
20892 empty initializer() rather than no initializer. This can
20893 only happen when the initializer is a pack expansion whose
20894 parameter packs are of length zero. */
20899 else
20900 {
20904 else
20905 {
20908 }
20909 }
20911 /* Avoid passing an enclosing decl to valid_array_size_p. */
20918 complain);
20926 }
20929 {
20935 complain));
20936 }
20939 {
20943 op0,
20947 }
20950 {
20951 tree function;
20955 tree ret;
20958 /* Internal function with no arguments. */
20962 /* When we parsed the expression, we determined whether or
20963 not Koenig lookup should be performed. */
20966 {
20969 }
20971 {
20976 }
20981 {
20982 /* Do nothing; calling tsubst_copy_and_build on an identifier
20983 would incorrectly perform unqualified lookup again.
20985 Note that we can also have an IDENTIFIER_NODE if the earlier
20986 unqualified lookup found a dependent local extern declaration
20987 (as per finish_call_expr); in that case koenig_p will be false
20988 and we do want to do the lookup again to find the substituted
20989 declaration. */
20993 /* Use tsubst_copy to substitute through the template arguments
20994 of the template-id without performing unqualified lookup of
20995 the template name. */
20997 }
20998 else
20999 {
21001 {
21007 }
21008 else
21013 /* Avoid error about taking the address of a constructor. */
21018 /* When KOENIG_P, we don't want to mark_used the callee before
21019 augmenting the overload set via ADL, so during this initial
21020 substitution we disable mark_used by setting tf_conv (68942). */
21026 }
21029 releasing_vec call_args;
21031 call_args);
21033 /* Stripped-down processing for a call in a thunk. Specifically, in
21034 the thunk template for a generic lambda. */
21036 {
21037 /* Now that we've expanded any packs, the number of call args
21038 might be different. */
21042 {
21049 }
21050 /* We aren't going to do normal overload resolution, so force the
21051 template-id to resolve. */
21054 {
21055 /* In a thunk, pass through args directly, without any
21056 conversions. */
21061 }
21063 {
21064 /* If there are no other args, just push 'this'. */
21067 else
21068 {
21069 /* Otherwise, shift the other args over to make room. */
21075 }
21076 }
21079 /* The thunk location is not interesting. */
21086 }
21088 /* We do not perform argument-dependent lookup if normal
21089 lookup finds a non-function, in accordance with the
21090 resolution of DR 218. */
21093 /* If lookup found a member function, the Koenig lookup is
21094 not appropriate, even if an unqualified-name was used
21095 to denote the function. */
21098 /* C++20 P0846: Lookup found nothing. */
21101 /* Only do this when substitution turns a dependent call
21102 into a non-dependent call. */
21114 {
21119 {
21120 /* For backwards compatibility and good diagnostics, try
21121 the unqualified lookup again if we aren't in SFINAE
21122 context. */
21129 {
21132 "and no declarations were found by "
21133 "argument-dependent lookup at the point "
21138 /* In a lambda fn, we have to be careful to not
21139 introduce new this captures. Legacy code can't
21140 be using lambdas anyway, so it's ok to be
21141 stricter. Be strict with C++20 template-id ADL too.
21142 And be strict if we're already failing anyway. */
21148 else
21152 {
21163 {
21166 "declarations in dependent base %qT are "
21172 else
21176 }
21177 else
21179 "%qD declared here, later in the "
21183 }
21186 }
21187 }
21189 {
21193 }
21194 }
21196 /* Remember that there was a reference to this entity. */
21205 /* Put back tf_decltype for the actual call. */
21210 {
21214 {
21216 "wrong number of arguments to "
21219 }
21220 else
21228 {
21230 "wrong number of arguments to "
21234 }
21238 complain);
21244 {
21246 complain);
21250 }
21255 {
21257 "wrong number of arguments to "
21260 }
21261 else
21262 {
21267 {
21270 }
21273 }
21277 /* Unsupported internal function with arguments. */
21279 }
21284 complain);
21286 {
21301 complain);
21302 else
21303 ret = (build_new_method_call
21308 complain));
21309 }
21311 {
21312 /* FUNCTION is a template-id referring to a concept definition. */
21317 /* Calls to standard and variable concepts should have been
21318 previously diagnosed. */
21321 /* Ensure the result is wrapped as a call expression. */
21323 }
21324 else
21327 koenig_p,
21328 complain);
21331 {
21337 {
21341 }
21343 /* This also suppresses -Wredundant-move. */
21345 }
21348 }
21351 {
21358 {
21360 {
21365 }
21366 else
21367 {
21372 }
21374 }
21375 else
21376 {
21379 }
21384 }
21387 {
21392 input_location));
21393 }
21399 {
21400 tree object;
21401 tree object_type;
21402 tree member;
21403 tree r;
21407 /* Remember that there was a reference to this entity. */
21418 else
21425 {
21428 }
21430 {
21432 complain);
21436 }
21440 {
21442 {
21447 {
21450 }
21452 {
21457 }
21458 }
21459 }
21462 {
21463 /* Lookup the template functions now that we know what the
21464 scope is. */
21471 {
21474 args);
21475 member = (adjust_result_of_qualified_name_lookup
21477 object_type));
21478 }
21479 else
21480 {
21482 input_location);
21484 }
21485 }
21489 {
21491 {
21495 else
21498 }
21500 }
21504 complain);
21508 }
21515 {
21522 tree r;
21531 /* We do not want to process the index of aggregate
21532 initializers as they are identifier nodes which will be
21533 looked up by digest_init. */
21537 {
21540 }
21545 {
21547 /* An identifier index is looked up in the type
21548 being initialized, not the current scope. */
21553 {
21554 /* Substitute into the pack expansion. */
21556 in_decl);
21560 ;
21562 /* Just move the argument into place. */
21564 else
21565 {
21566 /* Update the length of the final CONSTRUCTOR
21567 arguments vector, and note that we will need to
21568 copy.*/
21571 }
21572 }
21573 else
21575 }
21578 {
21583 {
21585 {
21590 }
21591 else
21593 }
21594 }
21602 {
21607 }
21611 }
21614 {
21617 {
21620 }
21621 else
21622 {
21625 }
21626 }
21631 /* Fall through */
21634 {
21636 /* ??? We're doing a subset of finish_id_expression here. */
21638 /* Replace an evaluated use of the thread_local variable with
21639 a call to its wrapper. */
21645 /* If the original type was a reference, we'll be wrapped in
21646 the appropriate INDIRECT_REF. */
21649 }
21652 {
21656 }
21659 {
21660 tree object_ptr
21666 }
21673 {
21680 }
21683 {
21692 /* If the resulting list of expression statement is empty,
21693 fold it further into void_node. */
21698 }
21701 {
21703 {
21704 /* We don't have a full set of template arguments yet; don't touch
21705 the lambda at all. */
21708 }
21712 }
21720 else
21721 /* Recreate the PAREN_EXPR from __builtin_assoc_barrier. */
21722 {
21726 }
21729 {
21734 complain));
21735 }
21738 {
21741 }
21744 /* No need to substitute further, a RANGE_EXPR will always be built
21745 with constant operands. */
21750 {
21754 /* We need to do this here as well as in tsubst_copy so we get the
21755 other tsubst_copy_and_build semantics for a PARM_DECL operand. */
21760 /* force_paren_expr can also create a VIEW_CONVERT_EXPR. */
21763 /* Otherwise, we're dealing with a wrapper to make a C++20 template
21764 parameter object const. */
21767 {
21768 /* The template argument is not const, presumably because
21769 it is still dependent, and so not the const template parm
21770 object. */
21774 {
21775 /* Don't add a wrapper to these. */
21778 }
21779 else
21780 /* Do add a wrapper otherwise (in particular, if op is
21781 another TEMPLATE_PARM_INDEX). */
21783 }
21785 }
21788 /* Handle Objective-C++ constructs, if appropriate. */
21789 {
21790 tree subst
21794 }
21796 }
21798 #undef RECUR
21799 #undef RETURN
21800 out:
21803 }
21805 /* Verify that the instantiated ARGS are valid. For type arguments,
21806 make sure that the type's linkage is ok. For non-type arguments,
21807 make sure they are constants if they are integral or enumerations.
21808 Emit an error under control of COMPLAIN, and return TRUE on error. */
21810 static bool
21812 {
21816 {
21826 }
21828 {
21829 /* [basic.link]: A name with no linkage (notably, the name
21830 of a class or enumeration declared in a local scope)
21831 shall not be used to declare an entity with linkage.
21832 This implies that names with no linkage cannot be used as
21833 template arguments
21835 DR 757 relaxes this restriction for C++0x. */
21840 {
21841 /* DR 488 makes use of a type with no linkage cause
21842 type deduction to fail. */
21844 {
21847 else
21850 }
21852 }
21853 /* In order to avoid all sorts of complications, we do not
21854 allow variably-modified types as template arguments. */
21856 {
21860 }
21861 }
21862 /* Class template and alias template arguments should be OK. */
21864 ;
21865 /* A non-type argument of integral or enumerated type must be a
21866 constant. */
21871 {
21875 }
21877 }
21879 static bool
21881 {
21886 {
21889 }
21893 }
21895 /* Call mark_used on each entity within the non-type template arguments in
21896 ARGS for an instantiation of TMPL, to ensure that each such entity is
21897 considered odr-used (and therefore marked for instantiation) regardless of
21898 whether the specialization was first formed in a template context (which
21899 inhibits mark_used).
21901 This function assumes push_to_top_level has been called beforehand. */
21903 static void
21905 {
21906 /* It suffices to do this only when instantiating a primary template. */
21910 /* We already marked outer arguments when specializing the context. */
21914 {
21915 /* A (pointer/reference to) function or variable NTTP argument. */
21918 {
21924 {
21925 /* Pass tf_none to avoid duplicate diagnostics: if this call
21926 fails then an earlier call to mark_used for this argument
21927 must have also failed and emitted a diagnostic. */
21930 }
21931 }
21932 /* A class NTTP argument. */
21935 {
21938 {
21941 }
21943 };
21946 }
21947 }
21948 }
21950 /* We're out of SFINAE context now, so generate diagnostics for the access
21951 errors we saw earlier when instantiating D from TMPL and ARGS. */
21953 static void
21955 {
21967 }
21969 /* Instantiate the indicated variable, function, or alias template TMPL with
21970 the template arguments in TARG_PTR. */
21972 tree
21974 {
21978 tree fndecl;
21979 tree gen_tmpl;
21980 tree spec;
21991 /* If this function is a clone, handle it specially. */
21993 {
21994 tree spec;
21995 tree clone;
21997 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
21998 DECL_CLONED_FUNCTION. */
22004 /* Look for the clone. */
22008 /* We should always have found the clone by now. */
22011 }
22016 /* Check to see if we already have this specialization. */
22020 /* targ_ptr only has the innermost template args, so add the outer ones
22021 from tmpl, which could be either a partial instantiation or gen_tmpl (in
22022 the case of a non-dependent call within a template definition). */
22023 targ_ptr = (add_outermost_template_args
22025 targ_ptr));
22027 /* It would be nice to avoid hashing here and then again in tsubst_decl,
22028 but it doesn't seem to be on the hot path. */
22032 || ((fndecl
22038 {
22040 {
22044 }
22046 }
22049 complain))
22052 /* We are building a FUNCTION_DECL, during which the access of its
22053 parameters and return types have to be checked. However this
22054 FUNCTION_DECL which is the desired context for access checking
22055 is not built yet. We solve this chicken-and-egg problem by
22056 deferring all checks until we have the FUNCTION_DECL. */
22059 /* Instantiation of the function happens in the context of the function
22060 template, not the context of the overload resolution we're doing. */
22062 /* If there are dependent arguments, e.g. because we're doing partial
22063 ordering, make sure processing_template_decl stays set. */
22067 {
22068 tree ctx;
22070 /* If the context of the partially instantiated template is
22071 already non-dependent, then we might as well use it. */
22073 else
22077 }
22083 {
22084 /* We need to determine if we're using a partial or explicit
22085 specialization now, because the type of the variable could be
22086 different. */
22092 {
22097 }
22098 }
22100 /* Substitute template parameters to obtain the specialization. */
22108 {
22111 }
22113 /* The DECL_TI_TEMPLATE should always be the immediate parent
22114 template, not the most general template. */
22120 /* Now we know the specialization, compute access previously
22121 deferred. Do no access control for inheriting constructors,
22122 as we already checked access for the inherited constructor. */
22125 {
22130 }
22133 /* If we've just instantiated the main entry point for a function,
22134 instantiate all the alternate entry points as well. We do this
22135 by cloning the instantiation of the main entry point, not by
22136 instantiating the template clones. */
22142 {
22144 {
22145 /* Remember to reinstantiate when we're out of SFINAE so the user
22146 can see the errors. */
22148 }
22150 }
22153 }
22155 /* Instantiate the alias template TMPL with ARGS. Also push a template
22156 instantiation level, which instantiate_template doesn't do because
22157 functions and variables have sufficient context established by the
22158 callers. */
22160 static tree
22162 {
22171 /* FIXME check for satisfaction in check_instantiated_args. */
22173 {
22175 {
22176 auto_diagnostic_group d;
22179 }
22181 }
22189 {
22190 /* An alias template specialization can be dependent
22191 even if its underlying type is not. */
22194 /* Sometimes a dependent alias spec is equivalent to its expansion,
22195 sometimes not. So always use structural_comptypes. */
22197 }
22200 }
22202 /* PARM is a template parameter pack for FN. Returns true iff
22203 PARM is used in a deducible way in the argument list of FN. */
22205 static bool
22207 {
22210 {
22212 tree packs;
22218 {
22219 /* The template parameter pack is used in a function parameter
22220 pack. If this is the end of the parameter list, the
22221 template parameter pack is deducible. */
22224 else
22225 /* Otherwise, not. Well, it could be deduced from
22226 a non-pack parameter, but doing so would end up with
22227 a deduction mismatch, so don't bother. */
22229 }
22230 }
22231 /* The template parameter pack isn't used in any function parameter
22232 packs, but it might be used deeper, e.g. tuple<Args...>. */
22234 }
22236 /* Subroutine of fn_type_unification: check non-dependent parms for
22237 convertibility. */
22239 static int
22243 {
22244 /* Non-constructor methods need to leave a conversion for 'this', which
22245 isn't included in nargs here. */
22251 {
22257 /* For a function parameter pack that occurs at the end of the
22258 parameter-declaration-list, the type A of each remaining
22259 argument of the call is compared with the type P of the
22260 declarator-id of the function parameter pack. */
22266 /* For a function parameter pack that does not occur at the
22267 end of the parameter-declaration-list, the type of the
22268 parameter pack is a non-deduced context. */
22272 {
22280 }
22283 }
22286 }
22288 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
22289 NARGS elements of the arguments that are being used when calling
22290 it. TARGS is a vector into which the deduced template arguments
22291 are placed.
22293 Returns either a FUNCTION_DECL for the matching specialization of FN or
22294 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
22295 true, diagnostics will be printed to explain why it failed.
22297 If FN is a conversion operator, or we are trying to produce a specific
22298 specialization, RETURN_TYPE is the return type desired.
22300 The EXPLICIT_TARGS are explicit template arguments provided via a
22301 template-id.
22303 The parameter STRICT is one of:
22305 DEDUCE_CALL:
22306 We are deducing arguments for a function call, as in
22307 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
22308 deducing arguments for a call to the result of a conversion
22309 function template, as in [over.call.object].
22311 DEDUCE_CONV:
22312 We are deducing arguments for a conversion function, as in
22313 [temp.deduct.conv].
22315 DEDUCE_EXACT:
22316 We are deducing arguments when doing an explicit instantiation
22317 as in [temp.explicit], when determining an explicit specialization
22318 as in [temp.expl.spec], or when taking the address of a function
22319 template, as in [temp.deduct.funcaddr]. */
22321 tree
22323 tree explicit_targs,
22324 tree targs,
22327 tree return_type,
22328 unification_kind_t strict,
22333 {
22334 tree parms;
22335 tree fntype;
22340 /* type_unification_real will pass back any access checks from default
22341 template argument substitution. */
22343 /* We don't have all the template args yet. */
22356 full_targs = (add_outermost_template_args
22358 targs));
22363 /* In C++0x, it's possible to have a function template whose type depends
22364 on itself recursively. This is most obvious with decltype, but can also
22365 occur with enumeration scope (c++/48969). So we need to catch infinite
22366 recursion and reject the substitution at deduction time; this function
22367 will return error_mark_node for any repeated substitution.
22369 This also catches excessive recursion such as when f<N> depends on
22370 f<N-1> across all integers, and returns error_mark_node for all the
22371 substitutions back up to the initial one.
22373 This is, of course, not reentrant. */
22382 {
22383 /* [temp.deduct]
22385 The specified template arguments must match the template
22386 parameters in kind (i.e., type, nontype, template), and there
22387 must not be more arguments than there are parameters;
22388 otherwise type deduction fails.
22390 Nontype arguments must match the types of the corresponding
22391 nontype template parameters, or must be convertible to the
22392 types of the corresponding nontype parameters as specified in
22393 _temp.arg.nontype_, otherwise type deduction fails.
22395 All references in the function type of the function template
22396 to the corresponding template parameters are replaced by the
22397 specified template argument values. If a substitution in a
22398 template parameter or in the function type of the function
22399 template results in an invalid type, type deduction fails. */
22410 explicit_targs);
22412 /* Adjust any explicit template arguments before entering the
22413 substitution context. */
22414 explicit_targs
22421 /* Substitute the explicit args into the function type. This is
22422 necessary so that, for instance, explicitly declared function
22423 arguments can match null pointed constants. If we were given
22424 an incomplete set of explicit args, we must not do semantic
22425 processing during substitution as we could create partial
22426 instantiations. */
22428 {
22433 /* Dig out the actual parm. */
22436 {
22439 }
22441 {
22444 }
22447 /* No explicit argument for this template parameter. */
22450 {
22451 /* Mark the argument pack as "incomplete". We could
22452 still deduce more arguments during unification.
22453 We remove this mark in type_unification_real. */
22458 /* We have some incomplete argument packs. */
22460 }
22461 }
22464 {
22466 {
22469 }
22472 /* Ignore any access checks; we'll see them again in
22473 instantiate_template and they might have the wrong
22474 access path at this point. */
22485 }
22487 /* Place the explicitly specified arguments in TARGS. */
22493 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
22495 }
22498 {
22504 }
22509 /* Never do unification on the 'this' parameter. */
22513 {
22514 /* We're deducing for a call to the result of a template conversion
22515 function. The parms we really want are in return_type. */
22519 }
22521 {
22523 }
22525 /* We allow incomplete unification without an error message here
22526 because the standard doesn't seem to explicitly prohibit it. Our
22527 callers must be ready to deal with unification failures in any
22528 event. */
22530 /* If we aren't explaining yet, push tinst context so we can see where
22531 any errors (e.g. from class instantiations triggered by instantiation
22532 of default template arguments) come from. If we are explaining, this
22533 context is redundant. */
22535 {
22538 }
22548 /* Now that we have bindings for all of the template arguments,
22549 ensure that the arguments deduced for the template template
22550 parameters have compatible template parameter lists. We cannot
22551 check this property before we have deduced all template
22552 arguments, because the template parameter types of a template
22553 template parameter might depend on prior template parameters
22554 deduced after the template template parameter. The following
22555 ill-formed example illustrates this issue:
22557 template<typename T, template<T> class C> void f(C<5>, T);
22559 template<int N> struct X {};
22561 void g() {
22562 f(X<5>(), 5l); // error: template argument deduction fails
22563 }
22565 The template parameter list of 'C' depends on the template type
22566 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
22567 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
22568 time that we deduce 'C'. */
22571 {
22574 }
22576 deduced:
22578 /* CWG2369: Check satisfaction before non-deducible conversions. */
22580 {
22584 }
22586 /* DR 1391: All parameters have args, now check non-dependent parms for
22587 convertibility. We don't do this if all args were explicitly specified,
22588 as the standard says that we substitute explicit args immediately. */
22594 /* All is well so far. Now, check:
22596 [temp.deduct]
22598 When all template arguments have been deduced, all uses of
22599 template parameters in nondeduced contexts are replaced with
22600 the corresponding deduced argument values. If the
22601 substitution results in an invalid type, as described above,
22602 type deduction fails. */
22604 {
22607 }
22609 /* Also collect access checks from the instantiation. */
22622 /* Now perform any access checks encountered during substitution. */
22629 /* If we're looking for an exact match, check that what we got
22630 is indeed an exact match. It might not be if some template
22631 parameters are used in non-deduced contexts. But don't check
22632 for an exact match if we have dependent template arguments;
22633 in that case we're doing partial ordering, and we already know
22634 that we have two candidates that will provide the actual type. */
22636 {
22640 tree sarg
22646 {
22650 }
22652 /* add_candidates uses DEDUCE_EXACT for x.operator foo(), but args
22653 doesn't contain the trailing void, and conv fns are always (). */
22655 {
22659 }
22660 }
22662 /* After doing deduction with the inherited constructor, actually return an
22663 instantiation of the inheriting constructor. */
22669 fail:
22672 {
22674 /* Reset once we're all the way out. */
22676 }
22679 }
22681 /* Returns true iff PARM is a forwarding reference in the context of
22682 template argument deduction for TMPL. */
22684 static bool
22686 {
22687 /* [temp.deduct.call], "A forwarding reference is an rvalue reference to a
22688 cv-unqualified template parameter ..." */
22693 {
22695 /* [temp.deduct.call], "... that does not represent a template parameter
22696 of a class template (during class template argument deduction)." */
22700 {
22701 /* Since the template parameters of a synthesized guide consist of
22702 the template parameters of the class template followed by those of
22703 the constructor (if any), we can tell if PARM represents a template
22704 parameter of the class template by comparing its index with the
22705 arity of the class template. */
22710 }
22712 }
22714 }
22716 /* Adjust types before performing type deduction, as described in
22717 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
22718 sections are symmetric. PARM is the type of a function parameter
22719 or the return type of the conversion function. ARG is the type of
22720 the argument passed to the call, or the type of the value
22721 initialized with the result of the conversion function.
22722 ARG_EXPR is the original argument expression, which may be null. */
22724 static int
22726 unification_kind_t strict,
22729 tree arg_expr)
22730 {
22734 {
22739 /* [temp.deduct.conv] First remove a reference type on parm.
22740 DRs 322 & 976 affected this. */
22744 /* Swap PARM and ARG throughout the remainder of this
22745 function; the handling is precisely symmetric since PARM
22746 will initialize ARG rather than vice versa. */
22752 /* Core issue #873: Do the DR606 thing (see below) for these cases,
22753 too, but here handle it by stripping the reference from PARM
22754 rather than by adding it to ARG. */
22759 /* Nothing else to do in this case. */
22764 }
22767 {
22768 /* [temp.deduct.call]
22770 If P is not a reference type:
22772 --If A is an array type, the pointer type produced by the
22773 array-to-pointer standard conversion (_conv.array_) is
22774 used in place of A for type deduction; otherwise,
22776 --If A is a function type, the pointer type produced by
22777 the function-to-pointer standard conversion
22778 (_conv.func_) is used in place of A for type deduction;
22779 otherwise,
22781 --If A is a cv-qualified type, the top level
22782 cv-qualifiers of A's type are ignored for type
22783 deduction. */
22788 else
22790 }
22792 /* [temp.deduct.call], "If P is a forwarding reference and the argument is
22793 an lvalue, the type 'lvalue reference to A' is used in place of A for
22794 type deduction." */
22797 /* try_one_overload doesn't provide an arg_expr, but
22798 functions are always lvalues. */
22802 /* [temp.deduct.call]
22804 If P is a cv-qualified type, the top level cv-qualifiers
22805 of P's type are ignored for type deduction. If P is a
22806 reference type, the type referred to by P is used for
22807 type deduction. */
22810 {
22813 }
22816 }
22818 /* Subroutine of fn_type_unification. PARM is a function parameter of a
22819 template which doesn't contain any deducible template parameters; check if
22820 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
22821 unify_one_argument. */
22823 static int
22827 {
22828 tree type;
22832 else
22840 {
22843 }
22845 {
22849 /* Avoid recalculating this in add_function_candidate. */
22850 ok = (*conv_p
22852 else
22856 }
22860 else
22862 }
22866 /* Returns true iff the expression EXPR is one from which a template
22867 argument can be deduced. In other words, if it's an undecorated
22868 use of a template non-type parameter. */
22870 static bool
22872 {
22873 /* Strip implicit conversions and implicit INDIRECT_REFs. */
22879 }
22881 /* Returns true iff the array domain DOMAIN uses a template parameter in a
22882 deducible way; that is, if it has a max value of <PARM> - 1. */
22884 static bool
22886 {
22895 }
22897 /* Returns true iff the template arguments ARGS use a template parameter
22898 in a deducible way. */
22900 static bool
22902 {
22904 {
22908 else
22909 {
22916 else
22918 }
22921 }
22923 }
22925 /* Returns true iff TYPE contains any deducible references to template
22926 parameters, as per 14.8.2.5. */
22928 static bool
22930 {
22934 /* T
22935 cv-list T
22936 TT<T>
22937 TT<i>
22938 TT<> */
22943 /* T*
22944 T&
22945 T&& */
22949 /* T[integer-constant ]
22950 type [i] */
22955 /* T type ::*
22956 type T::*
22957 T T::*
22958 T (type ::*)()
22959 type (T::*)()
22960 type (type ::*)(T)
22961 type (T::*)(T)
22962 T (type ::*)(T)
22963 T (T::*)()
22964 T (T::*)(T) */
22967 || (uses_deducible_template_parms
22970 /* template-name <T> (where template-name refers to a class template)
22971 template-name <i> (where template-name refers to a class template) */
22978 /* type (T)
22979 T()
22980 T(T) */
22982 {
22996 }
22999 }
23001 /* Subroutine of type_unification_real and unify_pack_expansion to
23002 handle unification of a single P/A pair. Parameters are as
23003 for those functions. */
23005 static int
23009 {
23016 /* We can't deduce anything from this, but we might get all the
23017 template args from other function args. */
23020 /* Implicit conversions (Clause 4) will be performed on a function
23021 argument to convert it to the type of the corresponding function
23022 parameter if the parameter type contains no template-parameters that
23023 participate in template argument deduction. */
23026 /* For function parameters with no deducible template parameters,
23027 just return. We'll check non-dependent conversions later. */
23031 {
23033 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
23034 | UNIFY_ALLOW_MORE_CV_QUAL
23048 }
23050 /* We only do these transformations if this is the top-level
23051 parameter_type_list in a call or declaration matching; in other
23052 situations (nested function declarators, template argument lists) we
23053 won't be comparing a type to an expression, and we don't do any type
23054 adjustments. */
23056 {
23058 {
23061 {
23062 /* [temp.deduct.type] A template-argument can be
23063 deduced from a pointer to function or pointer
23064 to member function argument if the set of
23065 overloaded functions does not contain function
23066 templates and at most one of a set of
23067 overloaded functions provides a unique
23068 match. */
23072 /* If a unique match was not found, this is a
23073 non-deduced context, so we still succeed. */
23075 }
23081 }
23085 }
23086 else
23091 /* For deduction from an init-list we need the actual list. */
23095 }
23097 /* for_each_template_parm callback that always returns 0. */
23099 static int
23101 {
23103 }
23105 /* for_each_template_parm any_fn callback to handle deduction of a template
23106 type argument from the type of an array bound. */
23108 static int
23110 {
23118 {
23124 }
23126 /* Keep walking. */
23128 }
23130 /* Try to deduce any not-yet-deduced template type arguments from the type of
23131 an array bound. This is handled separately from unify because 14.8.2.5 says
23132 "The type of a type parameter is only deduced from an array bound if it is
23133 not otherwise deduced." */
23135 static void
23137 {
23142 }
23144 /* Most parms like fn_type_unification.
23146 If SUBR is 1, we're being called recursively (to unify the
23147 arguments of a function or method parameter of a function
23148 template).
23150 CHECKS is a pointer to a vector of access checks encountered while
23151 substituting default template arguments. */
23153 static int
23155 tree full_targs,
23156 tree xparms,
23160 unification_kind_t strict,
23163 {
23168 tree parms;
23179 /* Reset the number of non-defaulted template arguments contained
23180 in TARGS. */
23183 again:
23188 /* Only fn_type_unification cares about terminal void. */
23195 {
23200 /* For a function parameter pack that occurs at the end of the
23201 parameter-declaration-list, the type A of each remaining
23202 argument of the call is compared with the type P of the
23203 declarator-id of the function parameter pack. */
23209 /* For a function parameter pack that does not occur at the
23210 end of the parameter-declaration-list, the type of the
23211 parameter pack is a non-deduced context. */
23218 explain_p))
23220 }
23225 {
23226 /* Unify the remaining arguments with the pack expansion type. */
23227 tree argvec;
23230 /* Allocate a TREE_VEC and copy in all of the arguments */
23235 /* Copy the parameter into parmvec. */
23241 /* Advance to the end of the list of parameters. */
23243 }
23245 /* Fail if we've reached the end of the parm list, and more args
23246 are present, and the parm list isn't variadic. */
23249 /* Fail if parms are left and they don't have default values and
23250 they aren't all deduced as empty packs (c++/57397). This is
23251 consistent with sufficient_parms_p. */
23254 {
23258 do
23259 {
23262 count++;
23264 }
23268 type_pack_p);
23269 }
23272 {
23273 tsubst_flags_t complain = (explain_p
23274 ? tf_warning_or_error
23279 {
23283 /* Clear the "incomplete" flags on all argument packs now so that
23284 substituting them into later default arguments works. */
23286 {
23289 }
23297 {
23302 }
23304 /* If this is an undeduced nontype parameter that depends on
23305 a type parameter, try another pass; its type may have been
23306 deduced from a later argument than the one from which
23307 this parameter can be deduced. */
23312 {
23315 }
23317 /* Core issue #226 (C++0x) [temp.deduct]:
23319 If a template argument has not been deduced, its
23320 default template argument, if any, is used.
23322 When we are in C++98 mode, TREE_PURPOSE will either
23323 be NULL_TREE or ERROR_MARK_NODE, so we do not need
23324 to explicitly check cxx_dialect here. */
23326 /* OK, there is a default argument. Wait until after the
23327 conversion check to do substitution. */
23330 /* If the type parameter is a parameter pack, then it will
23331 be deduced to an empty parameter pack. */
23333 {
23334 tree arg;
23337 {
23340 }
23341 else
23348 }
23351 }
23353 /* During partial ordering, we deduce dependent template args. */
23356 /* Now substitute into the default template arguments. */
23358 {
23363 {
23367 }
23382 {
23383 /* The type of this non-type parameter depends on undeduced
23384 parameters. Don't try to use its default argument yet,
23385 since we might deduce an argument for it on the next pass,
23386 but do check whether the arguments we already have cause
23387 substitution failure, so that that happens before we try
23388 later default arguments (78489). */
23391 NULL_TREE);
23395 else
23397 }
23398 else
23399 {
23400 /* Even if the call is happening in template context, getting
23401 here means it's non-dependent, and a default argument is
23402 considered a separate definition under [temp.decls], so we can
23403 do this substitution without processing_template_decl. This
23404 is important if the default argument contains something that
23405 might be instantiation-dependent like access (87480). */
23409 {
23410 /* First instatiate in template context, in case we still
23411 depend on undeduced template parameters. */
23414 NULL_TREE);
23418 /* We replaced all the tparms, substitute again out of
23419 template context. */
23421 }
23424 NULL_TREE);
23433 }
23442 {
23444 /* The position of the first default template argument,
23445 is also the number of non-defaulted arguments in TARGS.
23446 Record that. */
23449 }
23450 }
23454 }
23460 }
23462 /* Subroutine of type_unification_real. Args are like the variables
23463 at the call site. ARG is an overloaded function (or template-id);
23464 we try deducing template args from each of the overloads, and if
23465 only one succeeds, we go with that. Modifies TARGS and returns
23466 true on success. */
23468 static bool
23470 tree targs,
23471 tree parm,
23472 tree arg,
23473 unification_kind_t strict,
23476 {
23483 {
23486 }
23487 else
23491 /* Handle `&x' where `x' is some static or non-static member
23492 function name. */
23498 /* Strip baselink information. */
23503 {
23504 /* If we got some explicit template args, we need to plug them into
23505 the affected templates before we try to unify, in case the
23506 explicit args will completely resolve the templates in question. */
23513 {
23524 {
23529 {
23530 /* Instantiate the function to deduce its return type. */
23534 }
23543 {
23546 }
23547 }
23550 }
23551 /* If no templates (or more than one) are fully resolved by the
23552 explicit arguments, this template-id is a non-deduced context; it
23553 could still be OK if we deduce all template arguments for the
23554 enclosing call through other arguments. */
23557 }
23559 /* If ARG is, for example, "(0, &f)" then its type will be unknown
23560 -- but the deduction does not succeed because the expression is
23561 not just the function on its own. */
23563 else
23565 {
23570 {
23573 }
23574 }
23576 /* [temp.deduct.type] A template-argument can be deduced from a pointer
23577 to function or pointer to member function argument if the set of
23578 overloaded functions does not contain function templates and at most
23579 one of a set of overloaded functions provides a unique match.
23581 So if we found multiple possibilities, we return success but don't
23582 deduce anything. */
23585 {
23589 {
23594 /* Don't forget explicit template arguments in a pack. */
23598 }
23599 }
23604 }
23606 /* Core DR 115: In contexts where deduction is done and fails, or in
23607 contexts where deduction is not done, if a template argument list is
23608 specified and it, along with any default template arguments, identifies
23609 a single function template specialization, then the template-id is an
23610 lvalue for the function template specialization. */
23612 tree
23614 {
23627 {
23630 }
23632 {
23635 }
23637 {
23640 }
23643 {
23647 /* If we got some explicit template args, we need to plug them into
23648 the affected templates before we try to unify, in case the
23649 explicit args will completely resolve the templates in question. */
23657 {
23668 {
23671 {
23674 }
23677 {
23680 }
23681 }
23682 }
23684 {
23692 {
23693 tree base
23696 }
23700 }
23702 /* There were no good options and at least one bad one, so let the
23703 user know what the problem is. */
23705 }
23707 }
23709 /* As above, but error out if the expression remains overloaded. */
23711 tree
23713 {
23716 {
23720 }
23722 }
23724 /* Subroutine of resolve_overloaded_unification; does deduction for a single
23725 overload. Fills TARGS with any deduced arguments, or error_mark_node if
23726 different overloads deduce different arguments for a given parm.
23727 ADDR_P is true if the expression for which deduction is being
23728 performed was of the form "& fn" rather than simply "fn".
23730 Returns 1 on success. */
23732 static int
23734 tree orig_targs,
23735 tree targs,
23736 tree parm,
23737 tree arg,
23738 unification_kind_t strict,
23742 {
23744 tree tempargs;
23750 /* [temp.deduct.type] A template-argument can be deduced from a pointer
23751 to function or pointer to member function argument if the set of
23752 overloaded functions does not contain function templates and at most
23753 one of a set of overloaded functions provides a unique match.
23755 So if this is a template, just return success. */
23768 /* We don't copy orig_targs for this because if we have already deduced
23769 some template args from previous args, unify would complain when we
23770 try to deduce a template parameter for the same argument, even though
23771 there isn't really a conflict. */
23778 /* First make sure we didn't deduce anything that conflicts with
23779 explicitly specified args. */
23781 {
23788 /* Since we're unifying against ourselves, we will fill in
23789 template args used in the function parm list with our own
23790 template parms. Discard them. */
23793 {
23794 /* Check that the argument at each index of the deduced argument pack
23795 is equivalent to the corresponding explicitly specified argument.
23796 We may have deduced more arguments than were explicitly specified,
23797 and that's OK. */
23799 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
23800 that's wrong if we deduce the same argument pack from multiple
23801 function arguments: it's only incomplete the first time. */
23814 }
23817 }
23820 {
23825 }
23828 }
23830 /* PARM is a template class (perhaps with unbound template
23831 parameters). ARG is a fully instantiated type. If ARG can be
23832 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
23833 TARGS are as for unify. */
23835 static tree
23838 {
23847 /* We need to make a new template argument vector for the call to
23848 unify. If we used TARGS, we'd clutter it up with the result of
23849 the attempted unification, even if this class didn't work out.
23850 We also don't want to commit ourselves to all the unifications
23851 we've already done, since unification is supposed to be done on
23852 an argument-by-argument basis. In other words, consider the
23853 following pathological case:
23855 template <int I, int J, int K>
23856 struct S {};
23858 template <int I, int J>
23859 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
23861 template <int I, int J, int K>
23862 void f(S<I, J, K>, S<I, I, I>);
23864 void g() {
23865 S<0, 0, 0> s0;
23866 S<0, 1, 2> s2;
23868 f(s0, s2);
23869 }
23871 Now, by the time we consider the unification involving `s2', we
23872 already know that we must have `f<0, 0, 0>'. But, even though
23873 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
23874 because there are two ways to unify base classes of S<0, 1, 2>
23875 with S<I, I, I>. If we kept the already deduced knowledge, we
23876 would reject the possibility I=1. */
23884 else
23889 }
23891 /* Given a template type PARM and a class type ARG, find the unique
23892 base type in ARG that is an instance of PARM. We do not examine
23893 ARG itself; only its base-classes. If there is not exactly one
23894 appropriate base class, return NULL_TREE. PARM may be the type of
23895 a partial specialization, as well as a plain template type. Used
23896 by unify. */
23898 static enum template_base_result
23901 {
23903 tree binfo;
23909 {
23910 /* The type could not be completed. */
23913 }
23915 /* Walk in inheritance graph order. The search order is not
23916 important, and this avoids multiple walks of virtual bases. */
23918 {
23923 {
23924 /* If there is more than one satisfactory baseclass, then:
23926 [temp.deduct.call]
23928 If they yield more than one possible deduced A, the type
23929 deduction fails.
23931 applies. */
23933 {
23934 /* [temp.deduct.call]/4.3: If there is a class C that is a
23935 (direct or indirect) base class of D and derived (directly or
23936 indirectly) from a class B and that would be a valid deduced
23937 A, the deduced A cannot be B or pointer to B, respectively. */
23939 /* Ignore r. */
23943 else
23944 {
23947 }
23948 }
23951 }
23952 }
23956 }
23958 /* Returns the level of DECL, which declares a template parameter. */
23960 static int
23962 {
23964 {
23974 }
23976 }
23978 /* Decide whether ARG can be unified with PARM, considering only the
23979 cv-qualifiers of each type, given STRICT as documented for unify.
23980 Returns nonzero iff the unification is OK on that basis. */
23982 static int
23984 {
23990 {
23991 /* Although a CVR qualifier is ignored when being applied to a
23992 substituted template parameter ([8.3.2]/1 for example), that
23993 does not allow us to unify "const T" with "int&" because both
23994 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
23995 It is ok when we're allowing additional CV qualifiers
23996 at the outer level [14.8.2.1]/3,1st bullet. */
24005 }
24016 }
24018 /* Determines the LEVEL and INDEX for the template parameter PARM. */
24019 void
24021 {
24025 {
24028 }
24029 else
24030 {
24033 }
24034 }
24036 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
24037 do { \
24038 if (unify (TP, TA, P, A, S, EP)) \
24039 return 1; \
24040 } while (0)
24042 /* Unifies the remaining arguments in PACKED_ARGS with the pack
24043 expansion at the end of PACKED_PARMS. Returns 0 if the type
24044 deduction succeeds, 1 otherwise. STRICT is the same as in
24045 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
24046 function call argument list. We'll need to adjust the arguments to make them
24047 types. SUBR tells us if this is from a recursive call to
24048 type_unification_real, or for comparing two template argument
24049 lists. */
24051 static int
24055 {
24056 tree parm
24062 /* Add in any args remembered from an earlier partial instantiation. */
24070 /* Determine the parameter packs we will be deducing from the
24071 pattern, and record their current deductions. */
24074 {
24078 /* Only template parameter packs can be deduced, not e.g. function
24079 parameter packs or __bases or __integer_pack. */
24083 /* Determine the index and level of this parameter pack. */
24088 /* Keep track of the parameter packs and their corresponding
24089 argument packs. */
24092 }
24094 /* Loop through all of the arguments that have not yet been
24095 unified and unify each with the pattern. */
24097 {
24098 tree parm;
24102 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
24103 or the element of its argument pack at the current index if
24104 this argument was explicitly specified. */
24106 {
24115 {
24118 }
24120 }
24122 /* If we had explicit template arguments, substitute them into the
24123 pattern before deduction. */
24125 {
24126 /* Some arguments might still be unspecified or dependent. */
24134 NULL_TREE);
24139 }
24140 else
24143 /* Unify the pattern with the current argument. */
24145 explain_p))
24148 /* For each parameter pack, collect the deduced value. */
24150 {
24156 }
24157 }
24159 /* Verify that the results of unification with the parameter packs
24160 produce results consistent with what we've seen before, and make
24161 the deduced argument packs available. */
24163 {
24170 /* By default keep the original deduced argument pack.
24171 If necessary, more specific code is going to update the
24172 resulting deduced argument later down in this function. */
24176 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
24177 actually deduce anything. */
24185 {
24186 /* If we had fewer function args than explicit template args,
24187 just use the explicits. */
24192 }
24195 {
24196 tree result;
24197 /* Build the deduced *_ARGUMENT_PACK. */
24199 {
24202 }
24203 else
24208 /* Note the deduced argument packs for this parameter
24209 pack. */
24211 }
24215 {
24216 /* We only had the explicitly-provided arguments before, but
24217 now we have a complete set of arguments. */
24223 }
24224 else
24225 {
24229 /* During template argument deduction for the aggregate deduction
24230 candidate, the number of elements in a trailing parameter pack
24231 is only deduced from the number of remaining function
24232 arguments if it is not otherwise deduced. */
24235 /* FIXME This isn't set properly for partial instantiations. */
24241 /* Inconsistent unification of this parameter pack. */
24243 bad_old_arg,
24244 bad_new_arg);
24245 }
24246 }
24249 }
24251 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
24252 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
24253 parameters and return value are as for unify. */
24255 static int
24259 {
24260 tree parm_max;
24261 tree arg_max;
24265 /* Our representation of array types uses "N - 1" as the
24266 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
24267 not an integer constant. We cannot unify arbitrarily
24268 complex expressions, so we eliminate the MINUS_EXPRs
24269 here. */
24273 {
24276 }
24280 {
24281 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
24282 trying to unify the type of a variable with the type
24283 of a template parameter. For example:
24285 template <unsigned int N>
24286 void f (char (&) [N]);
24287 int g();
24288 void h(int i) {
24289 char a[g(i)];
24290 f(a);
24291 }
24293 Here, the type of the ARG will be "int [g(i)]", and
24294 may be a SAVE_EXPR, etc. */
24298 }
24300 /* If only one of the bounds used a MINUS_EXPR, compensate
24301 by adding one to the other bound. */
24304 integer_type_node,
24305 parm_max,
24306 integer_one_node);
24309 integer_type_node,
24310 arg_max,
24311 integer_one_node);
24315 }
24317 /* Returns whether T, a P or A in unify, is a type, template or expression. */
24321 static pa_kind_t
24323 {
24332 else
24334 }
24336 /* Deduce the value of template parameters. TPARMS is the (innermost)
24337 set of template parameters to a template. TARGS is the bindings
24338 for those template parameters, as determined thus far; TARGS may
24339 include template arguments for outer levels of template parameters
24340 as well. PARM is a parameter to a template function, or a
24341 subcomponent of that parameter; ARG is the corresponding argument.
24342 This function attempts to match PARM with ARG in a manner
24343 consistent with the existing assignments in TARGS. If more values
24344 are deduced, then TARGS is updated.
24346 Returns 0 if the type deduction succeeds, 1 otherwise. The
24347 parameter STRICT is a bitwise or of the following flags:
24349 UNIFY_ALLOW_NONE:
24350 Require an exact match between PARM and ARG.
24351 UNIFY_ALLOW_MORE_CV_QUAL:
24352 Allow the deduced ARG to be more cv-qualified (by qualification
24353 conversion) than ARG.
24354 UNIFY_ALLOW_LESS_CV_QUAL:
24355 Allow the deduced ARG to be less cv-qualified than ARG.
24356 UNIFY_ALLOW_DERIVED:
24357 Allow the deduced ARG to be a template base class of ARG,
24358 or a pointer to a template base class of the type pointed to by
24359 ARG.
24360 UNIFY_ALLOW_INTEGER:
24361 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
24362 case for more information.
24363 UNIFY_ALLOW_OUTER_LEVEL:
24364 This is the outermost level of a deduction. Used to determine validity
24365 of qualification conversions. A valid qualification conversion must
24366 have const qualified pointers leading up to the inner type which
24367 requires additional CV quals, except at the outer level, where const
24368 is not required [conv.qual]. It would be normal to set this flag in
24369 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
24370 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
24371 This is the outermost level of a deduction, and PARM can be more CV
24372 qualified at this point.
24373 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
24374 This is the outermost level of a deduction, and PARM can be less CV
24375 qualified at this point. */
24377 static int
24380 {
24382 tree targ;
24383 tree tparm;
24385 tsubst_flags_t complain = (explain_p
24386 ? tf_warning_or_error
24389 /* I don't think this will do the right thing with respect to types.
24390 But the only case I've seen it in so far has been array bounds, where
24391 signedness is the only information lost, and I think that will be
24392 okay. VIEW_CONVERT_EXPR can appear with class NTTP, thanks to
24393 finish_id_expression_1, and are also OK. */
24401 /* We can't deduce anything from this, but we might get all the
24402 template args from other function args. */
24408 /* If PARM uses template parameters, then we can't bail out here,
24409 even if ARG == PARM, since we won't record unifications for the
24410 template parameters. We might need them if we're trying to
24411 figure out which of two things is more specialized. */
24415 /* Handle init lists early, so the rest of the function can assume
24416 we're dealing with a type. */
24418 {
24419 tree elttype;
24424 /* We can only deduce from an initializer list argument if the
24425 parameter is std::initializer_list or an array; otherwise this
24426 is a non-deduced context. */
24431 else
24432 {
24434 /* Deduction is defined in terms of a single type, so just punt
24435 on the (bizarre) std::initializer_list<T...>. */
24438 }
24443 /* If ELTTYPE has no deducible template parms, skip deduction from
24445 else
24447 {
24455 {
24459 /* It should only be possible to get here for a call. */
24461 elt_strict |= maybe_adjust_types_for_deduction
24464 }
24467 explain_p);
24468 }
24472 {
24473 /* Also deduce from the length of the initializer list. */
24480 }
24482 /* If the std::initializer_list<T> deduction worked, replace the
24483 deduced A with std::initializer_list<A>. */
24485 {
24490 }
24492 }
24494 /* If parm and arg aren't the same kind of thing (template, type, or
24495 expression), fail early. */
24499 /* Immediately reject some pairs that won't unify because of
24500 cv-qualification mismatches. */
24503 /* It is the elements of the array which hold the cv quals of an array
24504 type, and the elements might be template type parms. We'll check
24505 when we recurse. */
24507 /* We check the cv-qualifiers when unifying with template type
24508 parameters below. We want to allow ARG `const T' to unify with
24509 PARM `T' for example, when computing which of two templates
24510 is more specialized, for example. */
24519 /* PMFs recurse at the same level, so don't strip this yet. */
24527 {
24531 /* In a type which contains a nested-name-specifier, template
24532 argument values cannot be deduced for template parameters used
24533 within the nested-name-specifier. */
24545 /* The PARM is not one we're trying to unify. Just check
24546 to see if it matches ARG. */
24547 {
24552 else
24554 }
24561 /* Check for mixed types and values. */
24569 {
24572 {
24573 /* First try to match ARG directly. */
24575 explain_p);
24577 {
24578 /* Otherwise, look for a suitable base of ARG, as below. */
24585 }
24586 }
24587 /* ARG must be constructed from a template class or a template
24588 template parameter. */
24593 /* Deduce arguments T, i from TT<T> or TT<i>. */
24599 /* If the template is a template template parameter, use the
24600 TEMPLATE_TEMPLATE_PARM for matching. */
24603 /* Fall through to deduce template name. */
24604 }
24608 {
24609 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
24611 /* Simple cases: Value already set, does match or doesn't. */
24616 }
24617 else
24618 {
24619 /* If PARM is `const T' and ARG is only `int', we don't have
24620 a match unless we are allowing additional qualification.
24621 If ARG is `const int' and PARM is just `T' that's OK;
24622 that binds `const int' to `T'. */
24627 /* Consider the case where ARG is `const volatile int' and
24628 PARM is `const T'. Then, T should be `volatile int'. */
24629 arg = cp_build_qualified_type
24634 /* Simple cases: Value already set, does match or doesn't. */
24640 /* Make sure that ARG is not a variable-sized array. (Note
24641 that were talking about variable-sized arrays (like
24642 `int[n]'), rather than arrays of unknown size (like
24643 `int[]').) We'll get very confused by such a type since
24644 the bound of the array is not constant, and therefore
24645 not mangleable. Besides, such types are not allowed in
24646 ISO C++, so we can do as we please here. We do allow
24647 them for 'auto' deduction, since that isn't ABI-exposed. */
24651 /* Strip typedefs as in convert_template_argument. */
24653 }
24655 /* If ARG is a parameter pack or an expansion, we cannot unify
24656 against it unless PARM is also a parameter pack. */
24661 /* If the argument deduction results is a METHOD_TYPE,
24662 then there is a problem.
24663 METHOD_TYPE doesn't map to any real C++ type the result of
24664 the deduction cannot be of that type. */
24678 {
24679 /* The PARM is not one we're trying to unify. Just check
24680 to see if it matches ARG. */
24686 }
24692 {
24696 /* We're deducing from an array bound, the type doesn't matter.
24697 This conversion should match the one below. */
24703 }
24705 /* [temp.deduct.type] If, in the declaration of a function template
24706 with a non-type template-parameter, the non-type
24707 template-parameter is used in an expression in the function
24708 parameter-list and, if the corresponding template-argument is
24709 deduced, the template-argument type shall match the type of the
24710 template-parameter exactly, except that a template-argument
24711 deduced from an array bound may be of any integral type.
24712 The non-type parameter might use already deduced type parameters. */
24715 /* We don't have enough levels of args to do any substitution. This
24717 else
24718 {
24724 {
24727 LOOKUP_NORMAL,
24731 }
24732 }
24736 /* Template-parameter dependent expression. Just accept it for now.
24737 It will later be processed in convert_template_argument. */
24738 ;
24742 /* OK. Ignore top-level quals here because a class-type template
24746 /* Convert the ARG to the type of PARM; the deduced non-type
24747 template argument must exactly match the types of the
24748 corresponding parameter. This conversion should match the
24749 one above. */
24752 {
24753 /* We haven't deduced the type of this parameter yet. */
24755 /* We deduce from array bounds in try_array_deduction. */
24758 {
24759 /* Deduce it from the non-type argument. As above, ignore
24760 top-level quals here too. */
24765 /* Now check whether the type of this parameter is still
24766 dependent, and give up if so. */
24772 }
24773 else
24774 /* Try again later. */
24776 }
24777 else
24780 /* If ARG is a parameter pack or an expansion, we cannot unify
24781 against it unless PARM is also a parameter pack. */
24786 {
24789 }
24794 {
24795 /* A pointer-to-member constant can be unified only with
24796 another constant. */
24800 /* Just unify the class member. It would be useless (and possibly
24801 wrong, depending on the strict flags) to unify also
24802 PTRMEM_CST_CLASS, because we want to be sure that both parm and
24803 arg refer to the same variable, even if through different
24804 classes. For instance:
24806 struct A { int x; };
24807 struct B : A { };
24809 Unification of &A::x and &B::x must succeed. */
24812 }
24815 {
24819 /* [temp.deduct.call]
24821 A can be another pointer or pointer to member type that can
24822 be converted to the deduced A via a qualification
24823 conversion (_conv.qual_).
24825 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
24826 This will allow for additional cv-qualification of the
24827 pointed-to types if appropriate. */
24830 /* The derived-to-base conversion only persists through one
24831 level of pointers. */
24836 }
24869 /* We have already checked cv-qualification at the top of the
24870 function. */
24874 /* As far as unification is concerned, this wins. Later checks
24875 will invalidate it if necessary. */
24878 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
24879 /* Type INTEGER_CST can come from ordinary constant template args. */
24891 {
24901 /* Check for pack expansions in the parameters. */
24903 {
24905 {
24907 /* We can unify against something with a trailing
24908 parameter pack. */
24910 else
24911 /* [temp.deduct.type]/9: If the template argument list of
24912 P contains a pack expansion that is not the last
24913 template argument, the entire template argument list
24914 is a non-deduced context. */
24916 }
24917 }
24919 /* If we don't have enough arguments to satisfy the parameters
24920 (not counting the pack expression at the end), or we have
24921 too many arguments for a parameter list that doesn't end in
24922 a pack expression, we can't unify. */
24928 /* Unify all of the parameters that precede the (optional)
24929 pack expression. */
24931 {
24936 }
24939 DEDUCE_EXACT,
24942 }
24950 {
24958 }
24963 {
24967 {
24968 /* First, we try to unify the PARM and ARG directly. */
24973 {
24974 /* Fallback to the special case allowed in
24975 [temp.deduct.call]:
24977 If P is a class, and P has the form
24978 template-id, then A can be a derived class of
24979 the deduced A. Likewise, if P is a pointer to
24980 a class of the form template-id, A can be a
24981 pointer to a derived class pointed to by the
24982 deduced A. */
24988 {
24989 /* Don't give the derived diagnostic if we're
24990 already dealing with the same template. */
24991 bool same_template
24997 }
24998 }
24999 }
25003 /* Perhaps PARM is something like S<U> and ARG is S<int>.
25004 Then, we should unify `int' and `U'. */
25006 else
25007 /* There's no chance of unification succeeding. */
25012 }
25019 {
25022 tree a;
25028 /* CV qualifications for methods can never be deduced, they must
25029 match exactly. We need to check them explicitly here,
25030 because type_unification_real treats them as any other
25031 cv-qualified parameter. */
25033 && (!check_cv_quals_for_unify
25061 {
25071 else
25072 {
25075 /* Here "less cv-qual" means the deduced arg (i.e. parm) has
25076 /more/ noexcept, since function pointer conversions are the
25077 reverse of qualification conversions. */
25082 else
25084 }
25085 }
25087 {
25088 /* As for noexcept. */
25095 else
25097 }
25100 }
25103 /* Unify a pointer to member with a pointer to member function, which
25104 deduces the type of the member as a function type. */
25106 {
25107 /* Check top-level cv qualifiers */
25115 /* Determine the type of the function we are unifying against. */
25119 }
25138 /* Matched cases are handled by the ARG == PARM test above. */
25142 /* We might get a variable as a non-type template argument in parm if the
25143 corresponding parameter is type-dependent. Make any necessary
25144 adjustments based on whether arg is a reference. */
25148 {
25153 }
25154 /* Now use the normal expression code to check whether they match. */
25165 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
25166 or TRAIT_TYPE nodes. */
25170 /* Unification fails if we hit an error node. */
25175 {
25185 }
25186 /* FALLTHRU */
25189 /* An unresolved overload is a nondeduced context. */
25195 expr:
25196 /* We must be looking at an expression. This can happen with
25197 something like:
25199 template <int I>
25200 void foo(S<I>, S<I + 2>);
25202 or
25204 template<typename T>
25205 void foo(A<T, T{}>);
25207 This is a "non-deduced context":
25209 [deduct.type]
25211 The non-deduced contexts are:
25213 --A non-type template argument or an array bound in which
25214 a subexpression references a template parameter.
25216 In these cases, we assume deduction succeeded, but don't
25217 actually infer any unifications. */
25222 else
25224 }
25225 }
25226 #undef RECUR_AND_CHECK_FAILURE
25227 \f
25228 /* Note that DECL can be defined in this translation unit, if
25229 required. */
25231 static void
25233 {
25234 tree clone;
25238 }
25240 /* Called if RESULT is explicitly instantiated, or is a member of an
25241 explicitly instantiated class. */
25243 void
25245 {
25248 /* If this entity has already been written out, it's too late to
25249 make any modifications. */
25253 /* consteval functions are never emitted. */
25258 /* For anonymous namespace we don't need to do anything. */
25260 {
25263 }
25266 /* The TREE_PUBLIC flag for function declarations will have been
25267 set correctly by tsubst. */
25271 {
25274 }
25275 else
25276 {
25279 /* Always make artificials weak. */
25282 /* For WIN32 we also want to put explicit instantiations in
25283 linkonce sections. */
25288 /* If the function has already been instantiated, clear DECL_EXTERNAL,
25289 since start_preparsed_function wouldn't have if we had an earlier
25290 extern explicit instantiation. */
25292 }
25294 /* If EXTERN_P, then this function will not be emitted -- unless
25295 followed by an explicit instantiation, at which point its linkage
25296 will be adjusted. If !EXTERN_P, then this function will be
25297 emitted here. In neither circumstance do we want
25298 import_export_decl to adjust the linkage. */
25300 }
25302 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
25303 important template arguments. If any are missing, we check whether
25304 they're important by using error_mark_node for substituting into any
25305 args that were used for partial ordering (the ones between ARGS and END)
25306 and seeing if it bubbles up. */
25308 static bool
25310 {
25314 {
25317 }
25319 {
25323 }
25325 }
25327 /* Given two function templates PAT1 and PAT2, return:
25329 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
25330 -1 if PAT2 is more specialized than PAT1.
25331 0 if neither is more specialized.
25333 LEN indicates the number of parameters we should consider
25334 (defaulted parameters should not be considered).
25336 The 1998 std underspecified function template partial ordering, and
25337 DR214 addresses the issue. We take pairs of arguments, one from
25338 each of the templates, and deduce them against each other. One of
25339 the templates will be more specialized if all the *other*
25340 template's arguments deduce against its arguments and at least one
25341 of its arguments *does* *not* deduce against the other template's
25342 corresponding argument. Deduction is done as for class templates.
25343 The arguments used in deduction have reference and top level cv
25344 qualifiers removed. Iff both arguments were originally reference
25345 types *and* deduction succeeds in both directions, an lvalue reference
25346 wins against an rvalue reference and otherwise the template
25347 with the more cv-qualified argument wins for that pairing (if
25348 neither is more cv-qualified, they both are equal). Unlike regular
25349 deduction, after all the arguments have been deduced in this way,
25350 we do *not* verify the deduced template argument values can be
25351 substituted into non-deduced contexts.
25353 The logic can be a bit confusing here, because we look at deduce1 and
25354 targs1 to see if pat2 is at least as specialized, and vice versa; if we
25355 can find template arguments for pat1 to make arg1 look like arg2, that
25356 means that arg2 is at least as specialized as arg1. */
25358 int
25360 {
25373 /* Remove the this parameter from non-static member functions. If
25374 one is a non-static member function and the other is not a static
25375 member function, remove the first parameter from that function
25376 also. This situation occurs for operator functions where we
25377 locate both a member function (with this pointer) and non-member
25378 operator (with explicit first operand). */
25380 {
25385 }
25387 {
25390 {
25391 len--;
25393 }
25394 }
25396 /* If only one is a conversion operator, they are unordered. */
25400 /* Consider the return type for a conversion function */
25402 {
25405 len++;
25406 }
25408 processing_template_decl++;
25414 /* Stop when an ellipsis is seen. */
25416 {
25427 {
25428 /* When both arguments are pack expansions, we need only
25429 unify the patterns themselves. */
25433 /* This is the last comparison we need to do. */
25435 }
25438 {
25442 }
25445 {
25449 }
25455 {
25461 /* Setup the parameter vector, which contains only ARG1. */
25464 /* Setup the argument vector, which contains the remaining
25465 arguments. */
25474 /* We cannot deduce in the other direction, because ARG1 is
25475 a pack expansion but ARG2 is not. */
25477 }
25479 {
25485 /* Setup the parameter vector, which contains only ARG1. */
25488 /* Setup the argument vector, which contains the remaining
25489 arguments. */
25498 /* We cannot deduce in the other direction, because ARG2 is
25499 a pack expansion but ARG1 is not.*/
25501 }
25503 else
25504 {
25505 /* The normal case, where neither argument is a pack
25506 expansion. */
25513 }
25515 /* If we couldn't deduce arguments for tparms1 to make arg1 match
25516 arg2, then arg2 is not as specialized as arg1. */
25522 /* "If, for a given type, deduction succeeds in both directions
25523 (i.e., the types are identical after the transformations above)
25524 and both P and A were reference types (before being replaced with
25525 the type referred to above):
25526 - if the type from the argument template was an lvalue reference and
25527 the type from the parameter template was not, the argument type is
25528 considered to be more specialized than the other; otherwise,
25529 - if the type from the argument template is more cv-qualified
25530 than the type from the parameter template (as described above),
25531 the argument type is considered to be more specialized than the other;
25532 otherwise,
25533 - neither type is more specialized than the other." */
25536 {
25538 {
25541 else
25543 }
25545 {
25550 }
25551 }
25554 /* We've failed to deduce something in either direction.
25555 These must be unordered. */
25560 /* We have already processed all of the arguments in our
25561 handing of the pack expansion type. */
25566 }
25568 /* "In most cases, all template parameters must have values in order for
25569 deduction to succeed, but for partial ordering purposes a template
25570 parameter may remain without a value provided it is not used in the
25571 types being used for partial ordering."
25573 Thus, if we are missing any of the targs1 we need to substitute into
25574 origs1, then pat2 is not as specialized as pat1. This can happen when
25575 there is a nondeduced context. */
25581 processing_template_decl--;
25583 /* If both deductions succeed, the partial ordering selects the more
25584 constrained template. */
25585 /* P2113: If the corresponding template-parameters of the
25586 template-parameter-lists are not equivalent ([temp.over.link]) or if
25587 the function parameters that positionally correspond between the two
25588 templates are not of the same type, neither template is more
25589 specialized than the other. */
25594 {
25600 }
25602 /* All things being equal, if the next argument is a pack expansion
25603 for one function but not for the other, prefer the
25604 non-variadic function. FIXME this is bogus; see c++/41958. */
25608 {
25611 }
25617 else
25619 }
25621 /* Determine which of two partial specializations of TMPL is more
25622 specialized.
25624 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
25625 to the first partial specialization. The TREE_PURPOSE is the
25626 innermost set of template parameters for the partial
25627 specialization. PAT2 is similar, but for the second template.
25629 Return 1 if the first partial specialization is more specialized;
25630 -1 if the second is more specialized; 0 if neither is more
25631 specialized.
25633 See [temp.class.order] for information about determining which of
25634 two templates is more specialized. */
25636 static int
25638 {
25639 tree targs;
25648 /* Just like what happens for functions, if we are ordering between
25649 different template specializations, we may encounter dependent
25650 types in the arguments, and we need our dependency check functions
25651 to behave correctly. */
25655 {
25658 }
25662 {
25665 }
25668 /* If both deductions succeed, the partial ordering selects the more
25669 constrained template. */
25673 /* In the case of a tie where at least one of the templates
25674 has a parameter pack at the end, the template with the most
25675 non-packed parameters wins. */
25677 && any_deductions
25680 {
25686 /* We don't count the pack expansion at the end. */
25696 }
25699 }
25701 /* Return the template arguments that will produce the function signature
25702 DECL from the function template FN, with the explicit template
25703 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
25704 also match. Return NULL_TREE if no satisfactory arguments could be
25705 found. */
25707 static tree
25709 {
25713 tree decl_arg_types;
25716 tree arg;
25720 /* Never do unification on the 'this' parameter. */
25742 }
25744 /* Return the innermost template arguments that, when applied to a partial
25745 specialization SPEC_TMPL of TMPL, yield the ARGS.
25747 For example, suppose we have:
25749 template <class T, class U> struct S {};
25750 template <class T> struct S<T*, int> {};
25752 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
25753 partial specialization and the ARGS will be {double*, int}. The resulting
25754 vector will be {double}, indicating that `T' is bound to `double'. */
25756 static tree
25758 {
25760 tree spec_args
25763 tree deduced_args;
25764 tree innermost_deduced_args;
25768 {
25772 innermost_deduced_args);
25773 }
25774 else
25778 again:
25787 {
25789 {
25795 }
25797 }
25800 {
25803 }
25805 /* Verify that nondeduced template arguments agree with the type
25806 obtained from argument deduction.
25808 For example:
25810 struct A { typedef int X; };
25811 template <class T, class U> struct C {};
25812 template <class T> struct C<T, typename T::X> {};
25814 Then with the instantiation `C<A, int>', we can deduce that
25815 `T' is `A' but unify () does not check whether `typename T::X'
25816 is `int'. */
25827 /* We only need to check the innermost arguments; the other
25828 arguments will always agree. */
25833 /* Now that we have bindings for all of the template arguments,
25834 ensure that the arguments deduced for the template template
25835 parameters have compatible template parameter lists. See the use
25836 of template_template_parm_bindings_ok_p in fn_type_unification
25837 for more information. */
25842 }
25844 // Compare two function templates T1 and T2 by deducing bindings
25845 // from one against the other. If both deductions succeed, compare
25846 // constraints to see which is more constrained.
25847 static int
25849 {
25854 {
25857 }
25860 {
25863 }
25865 // If both deductions succeed, then one may be more constrained.
25870 }
25872 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
25873 Return the TREE_LIST node with the most specialized template, if
25874 any. If there is no most specialized template, the error_mark_node
25875 is returned.
25877 Note that this function does not look at, or modify, the
25878 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
25879 returned is one of the elements of INSTANTIATIONS, callers may
25880 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
25881 and retrieve it from the value returned. */
25883 tree
25885 {
25892 {
25898 {
25899 /* Equally specialized, move to next function. If there
25900 is no next function, nothing's most specialized. */
25905 }
25906 }
25909 /* Now verify that champ is better than everything earlier in the
25910 instantiation list. */
25913 {
25916 }
25917 }
25919 processing_template_decl--;
25925 }
25927 /* If DECL is a specialization of some template, return the most
25928 general such template. Otherwise, returns NULL_TREE.
25930 For example, given:
25932 template <class T> struct S { template <class U> void f(U); };
25934 if TMPL is `template <class U> void S<int>::f(U)' this will return
25935 the full template. This function will not trace past partial
25936 specializations, however. For example, given in addition:
25938 template <class T> struct S<T*> { template <class U> void f(U); };
25940 if TMPL is `template <class U> void S<int*>::f(U)' this will return
25941 `template <class T> template <class U> S<T*>::f(U)'. */
25943 tree
25945 {
25947 {
25950 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
25951 template friend, or a FIELD_DECL for a capture pack. */
25954 }
25956 /* Look for more and more general templates. */
25958 {
25959 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
25960 (See cp-tree.h for details.) */
25969 /* Stop if we run into an explicitly specialized class template. */
25976 }
25979 }
25981 /* Return the most specialized of the template partial specializations
25982 which can produce TARGET, a specialization of some class or variable
25983 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
25984 a TEMPLATE_DECL node corresponding to the partial specialization, while
25985 the TREE_PURPOSE is the set of template arguments that must be
25986 substituted into the template pattern in order to generate TARGET.
25988 If the choice of partial specialization is ambiguous, a diagnostic
25989 is issued, and the error_mark_node is returned. If there are no
25990 partial specializations matching TARGET, then NULL_TREE is
25991 returned, indicating that the primary template should be used. */
25993 tree
25995 {
25998 {
26003 }
26005 {
26009 }
26011 {
26016 }
26017 else
26023 /* There are no partial specializations of this template. */
26029 /* For determining which partial specialization to use, only the
26030 innermost args are interesting. */
26033 {
26036 }
26038 /* The caller hasn't called push_to_top_level yet, but we need
26039 get_partial_spec_bindings to be done in non-template context so that we'll
26040 fully resolve everything. */
26041 processing_template_decl_sentinel ptds;
26045 {
26048 tree spec_tmpl;
26050 {
26051 /* Substitute in the template args from the enclosing class. */
26057 }
26058 else
26063 {
26067 /* Keep the candidate only if its constraints are satisfied. */
26069 {
26072 }
26073 }
26074 }
26082 {
26085 ;
26086 else
26087 {
26089 {
26092 {
26095 }
26096 }
26098 }
26099 }
26103 {
26106 {
26109 }
26110 }
26113 {
26120 else
26124 {
26129 }
26132 }
26135 }
26137 /* Explicitly instantiate DECL. */
26139 void
26141 {
26146 /* An error occurred, for which grokdeclarator has already issued
26147 an appropriate message. */
26150 {
26153 }
26155 {
26158 else
26161 }
26167 {
26168 /* There is an asymmetry here in the way VAR_DECLs and
26169 FUNCTION_DECLs are handled by grokdeclarator. In the case of
26170 the latter, the DECL we get back will be marked as a
26171 template instantiation, and the appropriate
26172 DECL_TEMPLATE_INFO will be set up. This does not happen for
26173 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
26174 should handle VAR_DECLs as it currently handles
26175 FUNCTION_DECLs. */
26177 {
26180 }
26183 {
26186 }
26188 {
26193 }
26194 }
26196 {
26199 }
26200 else
26203 /* Check for various error cases. Note that if the explicit
26204 instantiation is valid the RESULT will currently be marked as an
26205 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
26206 until we get here. */
26209 {
26210 /* DR 259 [temp.spec].
26212 Both an explicit instantiation and a declaration of an explicit
26213 specialization shall not appear in a program unless the explicit
26214 instantiation follows a declaration of the explicit specialization.
26216 For a given set of template parameters, if an explicit
26217 instantiation of a template appears after a declaration of an
26218 explicit specialization for that template, the explicit
26219 instantiation has no effect. */
26221 }
26223 {
26224 /* [temp.spec]
26226 No program shall explicitly instantiate any template more
26227 than once.
26229 We check DECL_NOT_REALLY_EXTERN so as not to complain when
26230 the first instantiation was `extern' and the second is not,
26231 and EXTERN_P for the opposite case. */
26234 /* If an "extern" explicit instantiation follows an ordinary
26235 explicit instantiation, the template is instantiated. */
26238 }
26240 {
26243 }
26245 {
26248 }
26251 ;
26253 {
26256 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
26259 }
26260 else
26268 }
26270 static void
26272 {
26278 {
26281 }
26282 }
26284 /* Perform an explicit instantiation of template class T. STORAGE, if
26285 non-null, is the RID for extern, inline or static. COMPLAIN is
26286 nonzero if this is called from the parser, zero if called recursively,
26287 since the standard is unclear (as detailed below). */
26289 void
26291 {
26293 {
26297 else
26300 }
26305 {
26308 t);
26310 }
26312 /* At most one of these will be true. */
26318 {
26320 {
26323 "ISO C++ 1998 forbids the use of %<extern%> on "
26325 }
26326 else
26328 "ISO C++ forbids the use of %qE"
26337 else
26339 storage);
26340 }
26343 /* DR 259 [temp.spec].
26345 Both an explicit instantiation and a declaration of an explicit
26346 specialization shall not appear in a program unless the
26347 explicit instantiation follows a declaration of the explicit
26348 specialization.
26350 For a given set of template parameters, if an explicit
26351 instantiation of a template appears after a declaration of an
26352 explicit specialization for that template, the explicit
26353 instantiation has no effect. */
26357 {
26358 /* We've already instantiated the template. */
26360 /* [temp.spec]
26362 No program shall explicitly instantiate any template more
26363 than once.
26365 If EXTERN_P then this is ok. */
26371 }
26379 /* In contrast to implicit instantiation, where only the
26380 declarations, and not the definitions, of members are
26381 instantiated, we have here:
26383 [temp.explicit]
26385 An explicit instantiation that names a class template
26386 specialization is also an explicit instantiation of the same
26387 kind (declaration or definition) of each of its members (not
26388 including members inherited from base classes and members
26389 that are templates) that has not been previously explicitly
26390 specialized in the translation unit containing the explicit
26391 instantiation, provided that the associated constraints, if
26392 any, of that member are satisfied by the template arguments
26393 of the explicit instantiation. */
26397 && !static_p
26401 {
26406 }
26408 {
26414 }
26415 }
26417 /* Given a function DECL, which is a specialization of TMPL, modify
26418 DECL to be a re-instantiation of TMPL with the same template
26419 arguments. TMPL should be the template into which tsubst'ing
26420 should occur for DECL, not the most general template.
26422 One reason for doing this is a scenario like this:
26424 template <class T>
26425 void f(const T&, int i);
26427 void g() { f(3, 7); }
26429 template <class T>
26430 void f(const T& t, const int i) { }
26432 Note that when the template is first instantiated, with
26433 instantiate_template, the resulting DECL will have no name for the
26434 first parameter, and the wrong type for the second. So, when we go
26435 to instantiate the DECL, we regenerate it. */
26437 static void
26439 {
26440 /* The arguments used to instantiate DECL, from the most general
26441 template. */
26444 /* Make sure that we can see identifiers, and compute access correctly. */
26448 {
26449 tree specs;
26453 /* Don't bother with this for unique friends that can't be redeclared and
26454 might change type if regenerated (PR69836). */
26458 /* Use the source location of the definition. */
26466 /* Instantiate a dynamic exception-specification. noexcept will be
26467 handled below. */
26470 {
26476 specs);
26477 }
26479 /* Merge parameter declarations. */
26483 {
26490 }
26493 {
26494 /* If we're regenerating a specialization, the contracts will have
26495 been copied from the most general template. Replace those with
26496 the ones from the actual specialization. */
26499 {
26502 }
26505 }
26507 /* Merge additional specifiers from the CODE_PATTERN. */
26513 }
26515 {
26524 }
26525 else
26528 done:
26530 }
26532 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
26533 substituted to get DECL. */
26535 tree
26537 {
26540 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
26541 for the instantiation. This is not always the most general
26542 template. Consider, for example:
26544 template <class T>
26545 struct S { template <class U> void f();
26546 template <> void f<int>(); };
26548 and an instantiation of S<double>::f<int>. We want TD to be the
26549 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
26551 more general template. */
26553 /* We must also deal with friend templates. Given:
26555 template <class T> struct S {
26556 template <class U> friend void f() {};
26557 };
26559 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
26560 so far as the language is concerned, but that's still
26561 where we get the pattern for the instantiation from. On
26562 other hand, if the definition comes outside the class, say:
26564 template <class T> struct S {
26565 template <class U> friend void f();
26566 };
26567 template <class U> friend void f() {}
26569 we don't need to look any further. That's what the check for
26570 DECL_INITIAL is for. */
26574 {
26575 /* The present template, TD, should not be a definition. If it
26576 were a definition, we should be using it! Note that we
26577 cannot restructure the loop to just keep going until we find
26578 a template with a definition, since that might go too far if
26579 a specialization was declared, but not defined. */
26581 /* Fetch the more general template. */
26583 }
26586 }
26588 /* Returns true if we need to instantiate this template instance even if we
26589 know we aren't going to emit it. */
26591 bool
26593 {
26594 /* We always instantiate inline functions so that we can inline them. An
26595 explicit instantiation declaration prohibits implicit instantiation of
26596 non-inline functions. With high levels of optimization, we would
26597 normally inline non-inline functions -- but we're not allowed to do
26598 that for "extern template" functions. Therefore, we check
26599 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
26603 /* And we need to instantiate static data members so that
26604 their initializers are available in integral constant
26605 expressions. */
26608 }
26610 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
26611 instantiate it now, modifying TREE_TYPE (fn). Returns false on
26612 error, true otherwise. */
26614 bool
26616 {
26620 /* Don't instantiate a noexcept-specification from template context. */
26630 {
26632 /* We're in start_preparsed_function, keep going. */
26639 }
26650 /* For a member friend template we can get a TEMPLATE_DECL. Let's use
26651 its FUNCTION_DECL for the rest of this function -- push_access_scope
26652 doesn't accept TEMPLATE_DECLs. */
26654 {
26657 }
26660 {
26665 }
26667 {
26671 {
26674 /* This might have failed because of an unparsed DMI, so
26675 let's try again later. */
26677 }
26679 {
26680 /* If hash_set::add returns true, the element was already there. */
26685 fn);
26687 }
26689 {
26697 {
26698 /* If needed, set current_class_ptr for the benefit of
26699 tsubst_copy/PARM_DECL. */
26704 }
26706 /* If this function is represented by a TEMPLATE_DECL, then
26707 the deferred noexcept-specification might still contain
26708 dependent types, even after substitution. And we need the
26709 dependency check functions to work in build_noexcept_spec. */
26713 /* Do deferred instantiation of the noexcept-specifier. */
26718 /* Build up the noexcept-specification. */
26728 }
26729 else
26734 }
26737 {
26738 /* This failed with a hard error, so let's go with false. */
26741 }
26748 }
26750 /* We're starting to process the function INST, an instantiation of PATTERN;
26751 add their parameters to local_specializations. */
26753 void
26755 {
26759 {
26763 }
26765 {
26767 {
26770 }
26771 else
26772 {
26773 /* Register the (value) argument pack as a specialization of
26774 TMPL_PARM, then move on. */
26777 }
26778 }
26780 }
26782 /* Instantiate the body of D using PATTERN with ARGS. We have
26783 already determined PATTERN is the correct template to use.
26784 NESTED_P is true if this is a nested function, in which case
26785 PATTERN will be a FUNCTION_DECL not a TEMPLATE_DECL. */
26787 static void
26789 {
26794 {
26797 }
26798 else
26799 /* Only OMP reductions are nested. */
26811 {
26812 /* The variable might be a lambda's extra scope, and that
26813 lambda's visibility depends on D's. */
26816 }
26818 /* Mark D as instantiated so that recursive calls to
26819 instantiate_decl do not try to instantiate it again. */
26823 /* Regenerate the declaration in case the template has been modified
26824 by a subsequent redeclaration. */
26827 /* We already set the file and line above. Reset them now in case
26828 they changed as a result of calling regenerate_decl_from_template. */
26832 {
26833 /* Clear out DECL_RTL; whatever was there before may not be right
26834 since we've reset the type of the declaration. */
26838 /* The initializer is placed in DECL_INITIAL by
26839 regenerate_decl_from_template so we don't need to
26840 push/pop_access_scope again here. Pull it out so that
26841 cp_finish_decl can process it. */
26847 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
26848 initializer. That function will defer actual emission until
26849 we have a chance to determine linkage. */
26852 /* Enter the scope of D so that access-checking works correctly. */
26862 }
26866 {
26867 /* Set up the list of local specializations. */
26871 /* Set up context. */
26874 else
26875 {
26879 }
26881 /* Create substitution entries for the parameters. */
26884 /* Substitute into the body of the function. */
26888 else
26889 {
26893 /* Set the current input_location to the end of the function
26894 so that finish_function knows where we are. */
26895 input_location
26898 /* Remember if we saw an infinite loop in the template. */
26899 current_function_infinite_loop
26901 }
26903 /* Finish the function. */
26906 else
26907 {
26910 }
26914 }
26916 /* We're not deferring instantiation any more. */
26924 }
26926 /* Produce the definition of D, a _DECL generated from a template. If
26927 DEFER_OK is true, then we don't have to actually do the
26928 instantiation now; we just have to do it sometime. Normally it is
26929 an error if this is an explicit instantiation but D is undefined.
26930 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
26931 instantiated class template. */
26933 tree
26935 {
26937 tree gen_args;
26938 tree args;
26939 tree td;
26940 tree code_pattern;
26941 tree spec;
26942 tree gen_tmpl;
26950 /* This function should only be used to instantiate templates for
26951 functions and static member variables. */
26954 /* A concept is never instantiated. */
26960 /* We may have a pending instantiation of D itself. */
26963 /* Variables are never deferred; if instantiation is required, they
26964 are instantiated right away. That allows for better code in the
26965 case that an expression refers to the value of the variable --
26966 if the variable has a constant value the referring expression can
26967 take advantage of that fact. */
26971 /* Don't instantiate cloned functions. Instead, instantiate the
26972 functions they cloned. */
26981 /* D has already been instantiated or explicitly specialized, so
26982 there's nothing for us to do here.
26984 It might seem reasonable to check whether or not D is an explicit
26985 instantiation, and, if so, stop here. But when an explicit
26986 instantiation is deferred until the end of the compilation,
26987 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
26988 the instantiation. */
26991 /* Check to see whether we know that this template will be
26992 instantiated in some other file, as with "extern template"
26993 extension. */
26996 /* In general, we do not instantiate such templates. */
27003 /* We should already have the extra args. */
27007 /* And what's in the hash table should match D. */
27009 == d
27012 /* This needs to happen before any tsubsting. */
27018 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
27019 for the instantiation. */
27024 {
27025 /* Look up an explicit specialization, if any. */
27028 {
27031 }
27032 }
27036 /* We should never be trying to instantiate a member of a class
27037 template or partial specialization. */
27042 /* In the case of a friend template whose definition is provided
27043 outside the class, we may have too many arguments. Drop the
27044 ones we don't need. The same is true for specializations. */
27045 args = get_innermost_template_args
27049 {
27055 }
27056 else
27057 {
27061 else
27063 }
27065 /* We may be in the middle of deferred access check. Disable it now. */
27068 /* Unless an explicit instantiation directive has already determined
27069 the linkage of D, remember that a definition is available for
27070 this entity. */
27080 /* If D is a member of an explicitly instantiated class template,
27081 and no definition is available, treat it like an implicit
27082 instantiation. */
27085 {
27086 /* Leave linkage flags alone on instantiations with anonymous
27087 visibility. */
27089 {
27092 }
27094 }
27096 /* Defer all other templates, unless we have been explicitly
27097 forbidden from doing so. */
27099 template. */
27100 ! pattern_defined
27101 /* If it's OK to postpone instantiation, do so. */
27102 || defer_ok
27103 /* If this is a static data member that will be defined
27104 elsewhere, we don't want to instantiate the entire data
27105 member, but we do want to instantiate the initializer so that
27106 we can substitute that elsewhere. */
27108 /* Handle here a deleted function too, avoid generating
27109 its body (c++/61080). */
27111 {
27112 /* The definition of the static data member is now required so
27113 we must substitute the initializer. */
27117 {
27118 tree ns;
27119 tree init;
27128 args,
27130 /* If instantiating the initializer involved instantiating this
27131 again, don't call cp_finish_decl twice. */
27133 {
27134 /* Make sure the initializer is still constant, in case of
27135 circular dependency (template/instantiate6.C). */
27136 const_init
27140 }
27144 }
27146 /* We restore the source position here because it's used by
27147 add_pending_template. */
27153 /* [temp.explicit]
27155 The definition of a non-exported function template, a
27156 non-exported member function template, or a non-exported
27157 member function or static data member of a class template
27158 shall be present in every translation unit in which it is
27159 explicitly instantiated. */
27163 /* If we're in unevaluated context, we just wanted to get the
27164 constant value; this isn't an odr use, so don't queue
27165 a full instantiation. */
27167 /* ??? Historically, we have instantiated inline functions, even
27168 when marked as "extern template". */
27171 }
27172 else
27173 {
27178 }
27187 }
27189 /* Run through the list of templates that we wish we could
27190 instantiate, and instantiate any we can. RETRIES is the
27191 number of times we retry pending template instantiation. */
27193 void
27195 {
27199 /* Instantiating templates may trigger vtable generation. This in turn
27200 may require further template instantiations. We place a limit here
27201 to avoid infinite loop. */
27203 {
27207 "template instantiation depth exceeds maximum of %d"
27208 " instantiating %q+D, possibly from virtual table generation"
27212 /* Pretend that we defined it. */
27215 }
27217 do
27218 {
27223 {
27228 {
27230 {
27245 }
27248 }
27249 else
27250 {
27253 {
27254 instantiation
27260 }
27264 }
27267 {
27268 /* If INSTANTIATION has been instantiated, then we don't
27269 need to consider it again in the future. */
27274 }
27275 else
27276 {
27279 }
27282 }
27284 }
27288 }
27290 /* Substitute ARGVEC into T, which is a list of initializers for
27291 either base class or a non-static data member. The TREE_PURPOSEs
27292 are DECLs, and the TREE_VALUEs are the initializer values. Used by
27293 instantiate_decl. */
27295 static tree
27297 {
27302 {
27303 tree decl;
27304 tree init;
27310 {
27311 tree expr;
27312 tree arg;
27314 /* Expand the base class expansion type into separate base
27315 classes. */
27317 tf_warning_or_error,
27318 NULL_TREE);
27322 /* We'll be building separate TREE_LISTs of arguments for
27323 each base. */
27329 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
27330 expand each argument in the TREE_VALUE of t. */
27337 /* VOID_TYPE_NODE is used to indicate
27338 value-initialization. */
27339 {
27342 }
27343 else
27344 {
27345 /* Substitute parameter packs into each argument in the
27346 TREE_LIST. */
27349 {
27350 tree expanded_exprs;
27352 /* Expand the argument. */
27353 tree value;
27356 else
27357 {
27360 }
27361 expanded_exprs
27363 tf_warning_or_error,
27364 NULL_TREE);
27368 /* Prepend each of the expanded expressions to the
27369 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
27377 else
27382 }
27385 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
27386 since we built them backwards. */
27388 {
27391 }
27392 }
27393 }
27396 {
27398 {
27402 }
27403 else
27404 {
27405 tree tmp;
27419 /* If we had an initializer but it instantiated to nothing,
27420 value-initialize the object. This will only occur when
27421 the initializer was a pack expansion where the parameter
27422 packs used in that expansion were of length zero. */
27425 }
27429 {
27431 decl);
27433 }
27434 /* Look for a target constructor. */
27438 {
27441 {
27445 }
27447 }
27450 {
27452 /* Carry over the dummy TREE_TYPE node containing the source
27453 location. */
27457 }
27458 }
27459 }
27461 }
27463 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
27464 is the instantiation (which should have been created with
27465 start_enum) and ARGS are the template arguments to use. */
27467 static void
27469 {
27470 tree e;
27476 {
27477 tree value;
27480 /* Note that in a template enum, the TREE_VALUE is the
27481 CONST_DECL, not the corresponding INTEGER_CST. */
27485 /* Give this enumeration constant the correct access. */
27488 /* Actually build the enumerator itself. Here we're assuming that
27489 enumerators can't have dependent attributes. */
27493 /* Attribute deprecated without an argument isn't sticky: it'll
27494 melt into a tree flag, so we need to propagate the flag here,
27495 since we just created a new enumerator. */
27498 }
27510 }
27512 /* DECL is a FUNCTION_DECL that is a template specialization. Return
27513 its type -- but without substituting the innermost set of template
27514 arguments. So, innermost set of template parameters will appear in
27515 the type. */
27517 tree
27519 {
27520 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
27522 }
27524 /* Return truthvalue if we're processing a template different from
27525 the last one involved in diagnostics. */
27526 bool
27528 {
27530 }
27532 /* Remember current template involved in diagnostics. */
27533 void
27535 {
27537 }
27541 {
27543 }
27545 /* Return TRUE if current_function_decl is being instantiated, false
27546 otherwise. */
27548 bool
27550 {
27554 }
27556 /* [temp.param] Check that template non-type parm TYPE is of an allowable
27557 type. Return false for ok, true for disallowed. Issue error and
27558 inform messages under control of COMPLAIN. */
27560 static bool
27562 {
27573 {
27575 {
27580 }
27582 }
27587 /* Fall through; before C++11 alias templates, a bound ttp
27590 /* Any other wildcard type not already handled above is allowed. */
27597 {
27605 {
27606 auto_diagnostic_group d;
27610 }
27612 }
27614 {
27619 }
27622 {
27625 else
27627 type);
27628 }
27630 }
27632 /* Returns true iff the noexcept-specifier for TYPE is value-dependent. */
27634 static bool
27636 {
27639 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
27640 affect overload resolution and treating it as dependent breaks
27641 things. Same for an unparsed noexcept expression. */
27648 }
27650 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
27651 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
27653 static bool
27655 {
27656 tree scope;
27658 /* [temp.dep.type]
27660 A type is dependent if it is:
27662 -- a template parameter. Template template parameters are types
27663 for us (since TYPE_P holds true for them) so we handle
27664 them here. */
27668 /* -- a qualified-id with a nested-name-specifier which contains a
27669 class-name that names a dependent type or whose unqualified-id
27670 names a dependent type. */
27674 /* An alias template specialization can be dependent even if the
27675 resulting type is not. */
27679 /* -- a cv-qualified type where the cv-unqualified type is
27680 dependent.
27681 No code is necessary for this bullet; the code below handles
27682 cv-qualified types, and we don't want to strip aliases with
27683 TYPE_MAIN_VARIANT because of DR 1558. */
27684 /* -- a compound type constructed from any dependent type. */
27692 {
27693 tree arg_type;
27698 arg_type;
27704 /* A value-dependent noexcept-specifier makes the type dependent. */
27707 }
27708 /* -- an array type constructed from any dependent type or whose
27709 size is specified by a constant expression that is
27710 value-dependent.
27712 We checked for type- and value-dependence of the bounds in
27713 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
27715 {
27720 }
27722 /* -- a template-id in which either the template name is a template
27723 parameter ... */
27726 /* ... or any of the template arguments is a dependent type or
27727 an expression that is type-dependent or value-dependent. */
27729 && (any_dependent_template_arguments_p
27733 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and TRAIT_TYPEs are
27734 dependent; if the argument of the `typeof' expression is not
27735 type-dependent, then it should already been have resolved. */
27741 /* A template argument pack is dependent if any of its packed
27742 arguments are. */
27744 {
27749 }
27751 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
27752 be template parameters. */
27762 /* The standard does not specifically mention types that are local
27763 to template functions or local classes, but they should be
27764 considered dependent too. For example:
27766 template <int I> void f() {
27767 enum E { a = I };
27768 S<sizeof (E)> s;
27769 }
27771 The size of `E' cannot be known until the value of `I' has been
27772 determined. Therefore, `E' must be considered dependent. */
27776 /* Don't use type_dependent_expression_p here, as it can lead
27777 to infinite recursion trying to determine whether a lambda
27778 nested in a lambda is dependent (c++/47687). */
27782 && (any_dependent_template_arguments_p
27786 /* Other types are non-dependent. */
27788 }
27790 /* Returns TRUE if TYPE is dependent, in the sense of
27791 [temp.dep.type]. Note that a NULL type is considered dependent. */
27793 bool
27795 {
27796 /* If there are no template parameters in scope, then there can't be
27797 any dependent types. */
27799 {
27800 /* If we are not processing a template, then nobody should be
27801 providing us with a dependent type. */
27805 }
27807 /* If the type is NULL, we have not computed a type for the entity
27808 in question; in that case, the type is dependent. */
27812 /* Erroneous types can be considered non-dependent. */
27816 /* If we have not already computed the appropriate value for TYPE,
27817 do so now. */
27819 {
27822 }
27825 }
27827 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
27828 lookup. In other words, a dependent type that is not the current
27829 instantiation. */
27831 bool
27833 {
27836 }
27838 /* True if we might find more declarations in SCOPE during instantiation than
27839 we can when parsing the template. */
27841 bool
27843 {
27845 }
27847 /* T is a SCOPE_REF. Return whether it represents a non-static member of
27848 an unknown base of 'this' (and is therefore instantiation-dependent). */
27850 static bool
27852 {
27869 }
27871 /* T is a SCOPE_REF; return whether we need to consider it
27872 instantiation-dependent so that we can check access at instantiation
27873 time even though we know which member it resolves to. */
27875 static bool
27877 {
27885 else
27887 }
27889 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
27890 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
27891 expression. */
27893 /* Note that this predicate is not appropriate for general expressions;
27894 only constant expressions (that satisfy potential_constant_expression)
27895 can be tested for value dependence. */
27897 bool
27899 {
27903 /* A type-dependent expression is also value-dependent. */
27908 {
27910 /* A dependent member function of the current instantiation. */
27914 /* A dependent member function of the current instantiation. */
27921 /* A name that has not been looked up -- must be dependent. */
27925 /* A non-type template parm. */
27929 /* A non-type template parm. */
27935 /* A constant with literal type and is initialized
27936 with an expression that is value-dependent. */
27940 {
27943 /* __PRETTY_FUNCTION__ inside a template function is dependent
27944 on the name of the function. */
27946 /* It might be used in a template, but not a template
27947 function, in which case its DECL_VALUE_EXPR will be
27948 "top level". */
27951 }
27953 /* FIXME cp_finish_decl doesn't fold reference initializers. */
27963 /* These expressions are value-dependent if the type to which
27964 the cast occurs is dependent or the expression being casted
27965 is value-dependent. */
27966 {
27972 /* A functional cast has a list of operands. */
27975 {
27976 /* If there are no operands, it must be an expression such
27977 as "int()". This should not happen for aggregate types
27978 because it would form non-constant expressions. */
27983 }
27993 }
27998 /* FALLTHRU */
28001 /* A `sizeof' expression is value-dependent if the operand is
28002 type-dependent or is a pack expansion. */
28011 /* An 'encode' expression is value-dependent if the operand is
28012 type-dependent. */
28021 /* All instantiation-dependent expressions should also be considered
28022 value-dependent. */
28030 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
28031 is value-dependent. */
28038 {
28054 }
28065 {
28069 }
28072 /* Treat all requires-expressions as value-dependent so
28073 we don't try to fold them. */
28080 {
28087 {
28089 /* In a call to a constexpr member function, look through the
28090 implicit ADDR_EXPR on the object argument so that it doesn't
28091 cause the call to be considered value-dependent. We also
28092 look through it in potential_constant_expression. */
28099 }
28101 }
28108 {
28110 tree val;
28117 }
28120 /* Treat a GNU statement expression as dependent to avoid crashing
28121 under instantiate_non_dependent_expr; it can't be constant. */
28126 /* The second operand is a type, which type_dependent_expression_p
28127 (and therefore value_dependent_expression_p) doesn't want to see. */
28133 /* A constant expression is value-dependent if any subexpression is
28134 value-dependent. */
28136 {
28143 {
28147 {
28150 /* In some cases, some of the operands may be missing.
28151 (For example, in the case of PREDECREMENT_EXPR, the
28152 amount to increment by may be missing.) That doesn't
28153 make the expression dependent. */
28156 }
28157 }
28161 }
28163 }
28165 /* The expression is not value-dependent. */
28167 }
28169 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
28170 [temp.dep.expr]. Note that an expression with no type is
28171 considered dependent. Other parts of the compiler arrange for an
28172 expression with type-dependent subexpressions to have no type, so
28173 this function doesn't have to be fully recursive. */
28175 bool
28177 {
28188 /* An unresolved name is always dependent. */
28194 /* A lambda-expression in template context is dependent. dependent_type_p is
28195 true for a lambda in the scope of a class or function template, but that
28196 doesn't cover all template contexts, like a default template argument. */
28200 /* A fold expression is type-dependent. */
28207 /* Some expression forms are never type-dependent. */
28220 /* The types of these expressions depends only on the type to which
28221 the cast occurs. */
28230 /* The types of these expressions depends only on the type created
28231 by the expression. */
28234 {
28235 /* For NEW_EXPR tree nodes created inside a template, either
28236 the object type itself or a TREE_LIST may appear as the
28237 operand 1. */
28240 /* This is an array type. We need to check array dimensions
28241 as well. */
28243 || value_dependent_expression_p
28245 /* Array type whose dimension has to be deduced. */
28249 else
28251 }
28254 {
28258 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
28259 contains an identifier associated by name lookup with one or more
28260 declarations declared with a dependent type, or...a
28261 nested-name-specifier or qualified-id that names a member of an
28262 unknown specialization. */
28265 }
28275 {
28280 }
28282 /* A static data member of the current instantiation with incomplete
28283 array type is type-dependent, as the definition and specializations
28284 can have different bounds. */
28291 /* An array of unknown bound depending on a variadic parameter, eg:
28293 template<typename... Args>
28294 void foo (Args... args)
28295 {
28296 int arr[] = { args... };
28297 }
28299 template<int... vals>
28300 void bar ()
28301 {
28302 int arr[] = { vals... };
28303 }
28305 If the array has no length and has an initializer, it must be that
28306 we couldn't determine its length in cp_complete_array_type because
28307 it is dependent. */
28315 /* Pull a FUNCTION_DECL out of a BASELINK if we can. */
28317 {
28322 }
28324 /* A function or variable template-id is type-dependent if it has any
28325 dependent template arguments. */
28329 {
28330 /* Consider the innermost template arguments, since those are the ones
28331 that come from the template-id; the template arguments for the
28332 enclosing class do not make it type-dependent unless they are used in
28333 the type of the decl. */
28335 && (any_dependent_template_arguments_p
28338 }
28340 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
28341 type-dependent. Checking this is important for functions with auto return
28342 type, which looks like a dependent type. */
28351 {
28355 }
28357 /* Otherwise, its constraints could still depend on outer template parameters
28358 from its (dependent) scope. */
28360 /* As an optimization, check this cheaper sufficient condition first.
28361 (At this point we've established that we're looking at a member of
28362 a dependent class, so it makes sense to start treating say undeduced
28363 auto as dependent.) */
28368 /* Always dependent, on the number of arguments if nothing else. */
28373 {
28378 {
28384 }
28385 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
28389 /* CO_AWAIT/YIELD_EXPR with unknown type is always dependent. */
28395 {
28400 }
28403 {
28410 }
28419 }
28421 /* The type of a non-type template parm declared with a placeholder type
28422 depends on the corresponding template argument, even though
28423 placeholders are not normally considered dependent. */
28430 /* Dependent type attributes might not have made it from the decl to
28431 the type yet. */
28437 }
28439 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
28440 type-dependent if the expression refers to a member of the current
28441 instantiation and the type of the referenced member is dependent, or the
28442 class member access expression refers to a member of an unknown
28443 specialization.
28445 This function returns true if the OBJECT in such a class member access
28446 expression is of an unknown specialization. */
28448 bool
28450 {
28451 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
28452 dependent. */
28457 }
28459 /* walk_tree callback function for instantiation_dependent_expression_p,
28460 below. Returns non-zero if a dependent subexpression is found. */
28462 static tree
28465 {
28467 {
28468 /* We don't have to worry about decltype currently because decltype
28469 of an instantiation-dependent expr is a dependent type. This
28470 might change depending on the resolution of DR 1172. */
28473 }
28476 {
28477 /* Don't treat an argument list as dependent just because it has no
28478 TREE_TYPE. */
28489 /* We'll check value-dependence separately. */
28492 /* Handle expressions with type operands. */
28497 {
28502 {
28505 else
28506 {
28509 }
28510 }
28512 }
28516 /* In a template, finish_class_member_access_expr creates a
28517 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
28518 type-dependent, so that we can check access control at
28519 instantiation time (PR 42277). See also Core issue 1273. */
28526 else
28529 /* Treat statement-expressions as dependent. */
28533 /* Treat requires-expressions as dependent. */
28544 /* Before C++17, a noexcept-specifier isn't part of the function type
28545 so it doesn't affect type dependence, but we still want to consider it
28546 for instantiation dependence. */
28555 }
28559 else
28561 }
28563 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
28564 sense defined by the ABI:
28566 "An expression is instantiation-dependent if it is type-dependent
28567 or value-dependent, or it has a subexpression that is type-dependent
28568 or value-dependent."
28570 Except don't actually check value-dependence for unevaluated expressions,
28571 because in sizeof(i) we don't care about the value of i. Checking
28572 type-dependence will in turn check value-dependence of array bounds/template
28573 arguments as needed. */
28575 bool
28577 {
28578 tree result;
28589 }
28591 /* As above, but also check value-dependence of the expression as a whole. */
28593 bool
28595 {
28597 || (processing_template_decl
28600 }
28602 /* Like type_dependent_expression_p, but it also works while not processing
28603 a template definition, i.e. during substitution or mangling. */
28605 bool
28607 {
28613 }
28615 /* Returns TRUE if ARGS contains a type-dependent expression. */
28617 bool
28619 {
28628 }
28630 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
28631 expressions) contains any type-dependent expressions. */
28633 bool
28635 {
28641 }
28643 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
28644 expressions) contains any value-dependent expressions. */
28646 bool
28648 {
28654 }
28656 /* Returns TRUE if the ARG (a template argument) is dependent. */
28658 bool
28660 {
28664 /* Assume a template argument that was wrongly written by the user
28665 is dependent. This is consistent with what
28666 any_dependent_template_arguments_p [that calls this function]
28667 does. */
28677 {
28680 /* A member template of a dependent class is not necessarily
28681 type-dependent, but it is a dependent template argument because it
28682 will be a member of an unknown specialization to that template. */
28685 }
28687 {
28693 }
28696 else
28698 }
28700 /* Identify any expressions that use function parms. */
28702 static tree
28704 {
28707 {
28710 }
28712 }
28714 /* Returns true if a type specialization formed using the template
28715 arguments ARGS needs to use structural equality. */
28717 bool
28719 {
28729 {
28732 {
28738 {
28739 /* Look inside the argument pack. */
28742 }
28745 {
28754 /* An any_targ_node argument (added by add_defaults_to_ttp)
28755 makes the corresponding specialization not canonicalizable,
28756 since template_args_equal always return true for it. We
28757 may see this when called from bind_template_template_parm. */
28759 /* Checking current_function_decl because this structural
28760 comparison is only necessary for redeclaration. */
28763 && (cp_walk_tree_without_duplicates
28765 /* The identity of a class template specialization that uses
28766 a function parameter depends on the identity of the function.
28767 And if this specialization appeared in the trailing return
28768 type thereof, we don't know the identity of the function
28769 (e.g. if it's a redeclaration or a new function) until we
28770 form its signature and go through duplicate_decls. Thus
28771 it's unsafe to decide on a canonical type now (which depends
28772 on the DECL_CONTEXT of the function parameter, which can get
28773 mutated after the fact by duplicate_decls), so just require
28774 structural equality in this case (PR52830). */
28776 }
28777 }
28778 }
28781 }
28783 /* Returns true if ARGS (a collection of template arguments) contains
28784 any dependent arguments. */
28786 bool
28788 {
28795 {
28800 }
28803 }
28805 /* Returns true if ARGS contains any errors. */
28807 bool
28809 {
28817 {
28820 else
28822 }
28828 {
28833 }
28836 }
28838 /* Returns TRUE if the template TMPL is type-dependent. */
28840 bool
28842 {
28844 {
28849 }
28851 /* Template template parameters are dependent. */
28855 /* So are names that have not been looked up. */
28859 }
28861 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
28863 bool
28865 {
28868 }
28870 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
28871 are dependent. */
28873 bool
28875 {
28882 {
28907 {
28911 }
28915 {
28919 {
28925 /* If this loop has a class iterator with != comparison
28926 with increment other than i++/++i/i--/--i, make sure the
28927 increment is constant. */
28930 {
28933 else
28937 }
28938 }
28939 }
28940 }
28943 }
28945 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
28946 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
28947 no such TYPE can be found. Note that this function peers inside
28948 uninstantiated templates and therefore should be used only in
28949 extremely limited situations. ONLY_CURRENT_P restricts this
28950 peering to the currently open classes hierarchy (which is required
28951 when comparing types). */
28953 tree
28955 {
28956 tree scope;
28957 tree name;
28958 tree decl;
28960 tree pushed_scope;
28961 tree result;
28966 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
28969 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
28970 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of a
28971 TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL
28972 representing the typedef. In that case TYPE_IDENTIFIER (type) is
28973 not the non-qualified identifier of the TYPENAME_TYPE anymore.
28974 So by getting the TYPE_IDENTIFIER of the _main declaration_ of
28975 the TYPENAME_TYPE instead, we avoid messing up with a possible
28976 typedef variant case. */
28979 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
28980 it first before we can figure out what NAME refers to. */
28982 {
28984 /* Given a class template A with a dependent base with nested type C,
28985 typedef typename A::C::C C will land us here, as trying to resolve
28986 the initial A::C leads to the local C typedef, which leads back to
28987 A::C::C. So we break the recursion now. */
28989 else
28991 }
28992 /* If we don't know what SCOPE refers to, then we cannot resolve the
28993 TYPENAME_TYPE. */
28996 /* If this is a typedef, we don't want to look inside (c++/11987). */
28999 /* If SCOPE isn't the template itself, it will not have a valid
29000 TYPE_FIELDS list. */
29002 /* scope is either the template itself or a compatible instantiation
29003 like X<T>, so look up the name in the original template. */
29005 /* If scope has no fields, it can't be a current instantiation. Check this
29006 before currently_open_class to avoid infinite recursion (71515). */
29009 /* If the SCOPE is not the current instantiation, there's no reason
29010 to look inside it. */
29013 /* Enter the SCOPE so that name lookup will be resolved as if we
29014 were in the class definition. In particular, SCOPE will no
29015 longer be considered a dependent type. */
29017 /* Look up the declaration. */
29019 tf_warning_or_error);
29023 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
29024 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
29030 {
29034 }
29037 {
29038 /* Obtain the template and the arguments. */
29041 {
29042 /* We get here with a plain identifier because a previous tentative
29043 parse of the nested-name-specifier as part of a ptr-operator saw
29044 ::template X<A>. The use of ::template is necessary in a
29045 ptr-operator, but wrong in a declarator-id.
29047 [temp.names]: In a qualified-id of a declarator-id, the keyword
29048 template shall not appear at the top level. */
29052 }
29054 /* Instantiate the template. */
29060 }
29062 /* Leave the SCOPE. */
29066 /* If we failed to resolve it, return the original typename. */
29070 /* If lookup found a typename type, resolve that too. */
29072 {
29073 /* Ill-formed programs can cause infinite recursion here, so we
29074 must catch that. */
29078 }
29080 /* Qualify the resulting type. */
29086 }
29088 /* EXPR is an expression which is not type-dependent. Return a proxy
29089 for EXPR that can be used to compute the types of larger
29090 expressions containing EXPR. */
29092 tree
29094 {
29096 tree inner_expr;
29098 /* When checking, try to get a constant value for all non-dependent
29099 expressions in order to expose bugs in *_dependent_expression_p
29100 and constexpr. This can affect code generation, see PR70704, so
29101 only do this for -fchecking=2. */
29104 /* Don't do this during nsdmi parsing as it can lead to
29105 unexpected recursive instantiations. */
29107 /* Don't do this during concept processing either and for
29108 the same reason. */
29114 /* Preserve OVERLOADs; the functions must be available to resolve
29115 types. */
29126 /* There is no need to return a proxy for a variable, parameter
29127 or enumerator. */
29131 /* Preserve string constants; conversions from string constants to
29132 "char *" are allowed, even though normally a "const char *"
29133 cannot be used to initialize a "char *". */
29136 /* Preserve void and arithmetic constants, as an optimization -- there is no
29137 reason to create a new node. */
29142 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
29143 There is at least one place where we want to know that a
29144 particular expression is a throw-expression: when checking a ?:
29145 expression, there are special rules if the second or third
29146 argument is a throw-expression. */
29150 /* Don't wrap an initializer list, we need to be able to look inside. */
29154 /* Don't wrap a dummy object, we need to be able to test for it. */
29172 /* If the type is unknown, it can't really be non-dependent */
29175 /* Otherwise, build a NON_DEPENDENT_EXPR. */
29178 }
29180 /* ARGS is a vector of expressions as arguments to a function call.
29181 Replace the arguments with equivalent non-dependent expressions.
29182 This modifies ARGS in place. */
29184 void
29186 {
29188 tree arg;
29191 {
29195 }
29196 }
29198 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
29199 TEMPLATE_TYPE_PARM with a level one deeper than the actual template parms,
29200 by default. If set_canonical is true, we set TYPE_CANONICAL on it. */
29202 static tree
29204 {
29220 }
29222 tree
29224 {
29226 }
29228 tree
29230 {
29232 }
29234 /* Return a C++17 deduction placeholder for class template TMPL.
29235 There are represented as an 'auto' with the special level 0 and
29236 CLASS_PLACEHOLDER_TEMPLATE set. */
29238 tree
29240 {
29243 /* Our canonical type depends on the placeholder. */
29246 }
29248 /* True iff T is a C++17 class template deduction placeholder. */
29250 bool
29252 {
29254 }
29256 /* Make a "constrained auto" type-specifier. This is an auto or
29257 decltype(auto) type with constraints that must be associated after
29258 deduction. The constraint is formed from the given concept CON
29259 and its optional sequence of template arguments ARGS.
29261 TYPE must be the result of make_auto_type or make_decltype_auto_type. */
29263 static tree
29265 {
29266 /* Build the constraint. */
29278 /* Our canonical type depends on the constraint. */
29281 /* Attach the constraint to the type declaration. */
29283 }
29285 /* Make a "constrained auto" type-specifier. */
29287 tree
29289 {
29292 }
29294 /* Make a "constrained decltype(auto)" type-specifier. */
29296 tree
29298 {
29301 }
29303 /* Returns true if the placeholder type constraint T has any dependent
29304 (explicit) template arguments. */
29306 static bool
29308 {
29313 {
29316 }
29323 }
29325 /* Build and return a concept definition. Like other templates, the
29326 CONCEPT_DECL node is wrapped by a TEMPLATE_DECL. This returns the
29327 the TEMPLATE_DECL. */
29329 tree
29331 {
29337 /* A concept-definition shall not have associated constraints. */
29339 {
29342 }
29344 /* A concept-definition shall appear in namespace scope. Templates
29345 aren't allowed in block scope, so we only need to check for class
29346 scope. */
29348 {
29351 }
29354 {
29357 }
29359 /* Initially build the concept declaration; its type is bool. */
29369 /* Push the enclosing template. */
29371 }
29373 /* Given type ARG, return std::initializer_list<ARG>. */
29375 static tree
29377 {
29382 {
29386 "deducing from brace-enclosed initializer list"
29390 }
29396 }
29398 /* Replace auto in TYPE with std::initializer_list<auto>. */
29400 static tree
29402 {
29409 }
29411 /* Hash traits for hashing possibly constrained 'auto'
29412 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
29415 {
29418 };
29420 /* Hash the 'auto' T. */
29422 inline hashval_t
29424 {
29426 /* Matching constrained-type-specifiers denote the same template
29427 parameter, so hash the constraint. */
29429 else
29430 /* But unconstrained autos are all separate, so just hash the pointer. */
29432 }
29434 /* Compare two 'auto's. */
29438 {
29445 /* Two unconstrained autos are distinct. */
29450 }
29452 /* for_each_template_parm callback for extract_autos: if t is a (possibly
29453 constrained) auto, add it to the vector. */
29455 static int
29457 {
29460 {
29461 /* All the autos were built with index 0; fix that up now. */
29465 /* If this is a repeated constrained-type-specifier, use the index we
29466 chose before. */
29468 else
29469 {
29470 /* Otherwise this is new, so use the current count. */
29473 }
29475 {
29480 }
29481 }
29483 /* Always keep walking. */
29485 }
29487 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
29488 says they can appear anywhere in the type. */
29490 static tree
29492 {
29500 {
29504 }
29507 }
29509 /* The stem for deduction guide names. */
29512 /* Return the name for a deduction guide for class template TMPL. */
29514 tree
29516 {
29527 }
29529 /* True if NAME is the name of a deduction guide. */
29531 bool
29533 {
29537 }
29539 /* True if FN is a deduction guide. */
29541 bool
29543 {
29548 }
29550 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
29552 bool
29554 {
29561 }
29563 /* True if FN is a guide generated from a constructor template. */
29565 bool
29567 {
29575 }
29577 /* True if FN is an aggregate initialization guide or the copy deduction
29578 guide. */
29580 bool
29582 {
29586 /* Explicitly declared. */
29589 /* Derived from a constructor. */
29592 }
29594 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
29595 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
29596 template parameter types. Note that the handling of template template
29597 parameters relies on current_template_parms being set appropriately for the
29598 new template. */
29600 static tree
29603 {
29609 tree newtype;
29612 {
29616 }
29617 else
29618 {
29621 {
29622 // Substitute once to fix references to other template parameters.
29625 // Now substitute again to reduce the level of the auto.
29628 }
29629 else
29632 }
29634 tree newdecl
29639 tree newidx;
29642 {
29651 {
29656 // First create a copy (ttargs) of tsubst_args with an
29657 // additional level for the template template parameter's own
29658 // template parameters (ttparms).
29659 tree ttparms = (INNERMOST_TEMPLATE_PARMS
29667 // Substitute ttargs into ttparms to fix references to
29668 // other template parameters.
29671 // Now substitute again with args based on tparms, to reduce
29672 // the level of the ttparms.
29675 complain);
29676 // Finally, tack the adjusted parms onto tparms.
29679 // As with all template template parms, the parameter list captured
29680 // by this template template parm that corresponds to its own level
29681 // should be empty. This avoids infinite recursion when structurally
29682 // comparing two such rewritten template template parms (PR102479).
29687 // All done.
29689 }
29693 else
29695 }
29696 else
29697 {
29699 tree newconst
29711 }
29714 }
29716 /* As rewrite_template_parm, but for the whole TREE_LIST representing a
29717 template parameter. */
29719 static tree
29722 {
29737 }
29739 /* Returns a C++17 class deduction guide template based on the constructor
29740 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
29741 guide, REFERENCE_TYPE for an implicit copy/move guide, or TREE_LIST for an
29742 aggregate initialization guide. OUTER_ARGS are the template arguments
29743 for the enclosing scope of the class. */
29745 static tree
29747 {
29751 location_t loc;
29755 {
29759 }
29762 {
29764 {
29768 else
29770 }
29773 else
29783 }
29784 else
29785 {
29791 fn_tmpl
29799 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
29800 fully specialized args for the enclosing class. Strip those off, as
29801 the deduction guide won't have those template parameters. */
29804 /* Discard the 'this' parameter. */
29812 {
29815 /* For a member template constructor, we need to flatten the two
29816 template parameter lists into one, and then adjust the function
29817 signature accordingly. This gets...complicated. */
29820 /* For a member template we should have two levels of parms/args, one
29821 for the class and one for the constructor. We stripped
29822 specialized args for further enclosing classes above. */
29826 /* Template args for translating references to the two-level template
29827 parameters into references to the one-level template parameters we
29828 are creating. */
29833 /* Template parms for the constructor template. */
29836 /* Template parms for the class template. */
29840 /* Template parms for the deduction guide start as a copy of the
29841 template parms for the class. We set current_template_parms for
29842 lookup_template_class_1. */
29848 /* Now we need to rewrite the constructor parms to append them to the
29849 class parms. */
29851 {
29855 tree newelt
29861 }
29863 /* Now we have a final set of template parms to substitute into the
29864 function signature. */
29871 {
29873 /* FIXME: We'd like to avoid substituting outer template
29874 arguments into the constraint ahead of time, but the
29875 construction of tsubst_args assumes that outer arguments
29876 are already substituted in. */
29879 }
29881 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped if
29882 cp_unevaluated_operand. */
29883 cp_evaluated ev;
29886 }
29887 else
29888 {
29889 /* Substitute in the same arguments to rewrite class members into
29890 references to members of an unknown specialization. */
29891 cp_evaluated ev;
29895 {
29897 /* FIXME: As above. */
29900 }
29901 }
29906 }
29909 {
29910 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
29914 }
29918 FUNCTION_DECL,
29933 }
29935 /* Add to LIST the member types for the reshaped initializer CTOR. */
29937 static tree
29939 {
29943 {
29947 {
29953 }
29957 /* Give the trailing pack expansion parameter a default argument to
29958 match aggregate initialization behavior, even if we deduce the
29959 length of the pack separately to more than we have initializers. */
29961 /* if ei is of array type and xi is a braced-init-list or string literal,
29962 Ti is an rvalue reference to the declared type of ei */
29967 {
29969 ftype = cp_build_qualified_type
29971 ftype = (cp_build_reference_type
29973 }
29975 }
29978 }
29980 /* Return whether ETYPE is, or is derived from, a specialization of TMPL. */
29982 static bool
29984 {
29990 tree tparms = (INNERMOST_TEMPLATE_PARMS
29997 }
30001 /* Return a C++20 aggregate deduction candidate for TYPE initialized from
30002 INIT. */
30004 static tree
30006 {
30014 {
30020 }
30022 /* We might be creating a guide for a class member template, e.g.,
30024 template<typename U> struct A {
30025 template<typename T> struct B { T t; };
30026 };
30028 At this point, A will have been instantiated. Below, we need to
30029 use both A<U>::B<T> (TEMPLATE_TYPE) and A<int>::B<T> (TYPE) types. */
30030 const bool member_template_p
30034 tree template_type = (member_template_p
30040 /* No aggregate candidate for copy-initialization. */
30042 {
30046 }
30048 /* If we encounter a problem, we just won't add the candidate. */
30053 {
30058 /* If we're creating a deduction guide for a member class template,
30059 we've used the original template pattern type for the reshape_init
30060 above; this is done because we want PARMS to be a template parameter
30061 type, something that can be deduced when used as a function template
30062 parameter. At this point the outer class template has already been
30063 partially instantiated (we deferred the deduction until the enclosing
30064 scope is non-dependent). Therefore we have to partially instantiate
30065 PARMS, so that its template level is properly reduced and we don't get
30066 mismatches when deducing types using the guide with PARMS. */
30068 {
30072 }
30073 }
30075 {
30078 len;
30080 {
30086 }
30087 }
30088 else
30089 /* Aggregate initialization doesn't apply to an initializer expression. */
30093 {
30099 }
30102 }
30104 /* UGUIDES are the deduction guides for the underlying template of alias
30105 template TMPL; adjust them to be deduction guides for TMPL. */
30107 static tree
30109 {
30110 /* [over.match.class.deduct]: When resolving a placeholder for a deduced
30111 class type (9.2.8.2) where the template-name names an alias template A,
30112 the defining-type-id of A must be of the form
30114 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
30116 as specified in 9.2.8.2. The guides of A are the set of functions or
30117 function templates formed as follows. For each function or function
30118 template f in the guides of the template named by the simple-template-id
30119 of the defining-type-id, the template arguments of the return type of f
30120 are deduced from the defining-type-id of A according to the process in
30121 13.10.2.5 with the exception that deduction does not fail if not all
30122 template arguments are deduced. Let g denote the result of substituting
30123 these deductions into f. If substitution succeeds, form a function or
30124 function template f' with the following properties and add it to the set
30125 of guides of A:
30127 * The function type of f' is the function type of g.
30129 * If f is a function template, f' is a function template whose template
30130 parameter list consists of all the template parameters of A (including
30131 their default template arguments) that appear in the above deductions or
30132 (recursively) in their default template arguments, followed by the
30133 template parameters of f that were not deduced (including their default
30134 template arguments), otherwise f' is not a function template.
30136 * The associated constraints (13.5.2) are the conjunction of the
30137 associated constraints of g and a constraint that is satisfied if and only
30138 if the arguments of A are deducible (see below) from the return type.
30140 * If f is a copy deduction candidate (12.4.1.8), then f' is considered to
30141 be so as well.
30143 * If f was generated from a deduction-guide (12.4.1.8), then f' is
30144 considered to be so as well.
30146 * The explicit-specifier of f' is the explicit-specifier of g (if
30147 any). */
30157 {
30164 {
30168 /* Deduce template arguments for f from the type-id of A. */
30174 /* CWG2664: Discard any deductions, still build the guide. */
30178 /* The number of parms for f' is the number of parms of A used in
30179 the deduced arguments plus non-deduced parms of f. */
30191 /* Set current_template_parms as in build_deduction_guide. */
30199 /* First copy over the used parms of A. */
30202 {
30205 {
30210 }
30211 }
30214 /* Adjust the deduced template args for f to refer to the A parms
30215 with their new indexes. */
30219 /* Now rewrite the non-deduced parms of f. */
30222 {
30229 }
30232 /* Substitute the deduced arguments plus the rewritten template
30233 parameters into f to get g. This covers the type, copyness,
30234 guideness, and explicit-specifier. */
30235 tree g;
30236 {
30237 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped
30238 if cp_unevaluated_operand. */
30239 cp_evaluated ev;
30241 }
30245 {
30246 /* The targs are all non-dependent, so g isn't a template. */
30250 }
30259 /* Substitute the associated constraints. */
30266 /* Add a constraint that the return type matches the instantiation of
30267 A with the same template arguments. */
30270 /* FIXME this should mean they don't compare as equivalent. */
30272 {
30275 }
30278 {
30281 }
30282 }
30283 else
30284 {
30285 /* For a non-template deduction guide, if the arguments of A aren't
30286 deducible from the return type, don't add the candidate. */
30287 non_template:
30290 }
30293 }
30296 }
30298 /* True iff template arguments for TMPL can be deduced from TYPE.
30299 Used to implement CPTK_IS_DEDUCIBLE for alias CTAD according to
30300 [over.match.class.deduct].
30302 This check is specified in terms of partial specialization, so the behavior
30303 should be parallel to that of get_partial_spec_bindings. */
30305 bool
30307 {
30313 /* If tmpl is a class template, this is trivial: it's deducible if TYPE is a
30314 specialization of TMPL. */
30320 /* Otherwise it's an alias template. */
30321 again:
30326 /* We don't fail on an undeduced targ the second time through (like
30327 get_partial_spec_bindings) because we're going to try defaults. */
30330 {
30336 {
30341 }
30342 /* If the type parameter is a parameter pack, then it will be deduced
30343 to an empty parameter pack. This is another case that doesn't model
30344 well as partial specialization. */
30346 {
30347 tree arg;
30349 {
30352 }
30353 else
30357 }
30358 }
30360 /* Maybe add in default template args. This seems like a flaw in the
30361 specification in terms of partial specialization, since it says the
30362 partial specialization has the the template parameter list of A, but a
30363 partial specialization can't have default targs. */
30368 /* I believe we don't need the template_template_parm_bindings_ok_p call
30369 because coerce_template_parms did coerce_template_template_parms. */
30372 }
30374 /* Return artificial deduction guides built from the constructors of class
30375 template TMPL. */
30377 static tree
30379 {
30386 {
30387 /* Skip inherited constructors. */
30393 }
30395 /* Add implicit default constructor deduction guide. */
30397 {
30399 complain);
30401 }
30403 /* Add copy guide. */
30404 {
30407 complain);
30409 }
30412 }
30416 /* Return the non-aggregate deduction guides for deducible template TMPL. The
30417 aggregate candidate is added separately because it depends on the
30418 initializer. Set ANY_DGUIDES_P if we find a non-implicit deduction
30419 guide. */
30421 static tree
30423 {
30426 {
30430 complain);
30431 }
30432 else
30433 {
30439 else
30441 }
30443 /* Cache the deduction guides for a template. We also remember the result of
30444 lookup, and rebuild everything if it changes; should be very rare. */
30448 {
30452 }
30453 else
30454 {
30457 }
30462 else
30463 {
30467 }
30471 }
30473 /* Return whether TMPL is a (class template argument-) deducible template. */
30475 bool
30477 {
30478 /* A deducible template is either a class template or is an alias template
30479 whose defining-type-id is of the form
30481 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
30483 where the nested-name-specifier (if any) is non-dependent and the
30484 template-name of the simple-template-id names a deducible template. */
30495 }
30497 /* Deduce template arguments for the class template placeholder PTYPE for
30498 template TMPL based on the initializer INIT, and return the resulting
30499 type. */
30501 static tree
30504 {
30505 /* We should have handled this in the caller. */
30509 /* If the class was erroneous, don't try to deduce, because that
30510 can generate a lot of diagnostic. */
30516 /* Wait until the enclosing scope is non-dependent. */
30521 /* Initializing one placeholder from another. */
30532 {
30536 }
30538 {
30540 {
30541 /* Be permissive with equivalent alias templates. */
30544 bool complained
30546 "alias template deduction only available "
30551 {
30554 }
30555 }
30556 else
30558 }
30560 /* Wait until the initializer is non-dependent. */
30564 /* Don't bother with the alias rules for an equivalent template. */
30577 {
30582 {
30583 /* As an exception, the first phase in 16.3.1.7 (considering the
30584 initializer list as a single argument) is omitted if the
30585 initializer list consists of a single expression of type cv U,
30586 where U is a specialization of C or a class derived from a
30587 specialization of C. */
30591 }
30594 else
30596 }
30599 else
30602 /* Do this now to avoid problems with erroneous args later on. */
30612 /* Prune explicit deduction guides in copy-initialization context (but
30613 not copy-list-initialization). */
30616 {
30622 {
30623 /* Found a nonconverting guide, prune the candidates. */
30630 }
30631 }
30639 /* If this is list-initialization and the class has a list guide, first
30640 try deducing from the list as a single argument, as [over.match.list]. */
30642 {
30650 {
30651 /* That didn't work, now try treating the list as a sequence of
30652 arguments. */
30658 }
30659 }
30662 {
30664 " of %qT, as it has no non-explicit deduction guides or "
30667 }
30669 {
30673 }
30679 {
30681 {
30687 }
30689 }
30690 /* [over.match.list]/1: In copy-list-initialization, if an explicit
30691 constructor is chosen, the initialization is ill-formed. */
30693 {
30695 {
30697 {
30698 // TODO: Pass down location from cp_finish_decl.
30700 "explicit deduction guide selected in "
30705 }
30707 }
30708 }
30710 /* If CTAD succeeded but the type doesn't have any explicit deduction
30711 guides, this deduction might not be what the user intended. */
30713 {
30717 "%qT may not intend to support class template argument "
30721 }
30725 }
30727 /* Return true if INIT is an unparenthesized id-expression or an
30728 unparenthesized class member access. Used for the argument of
30729 decltype(auto). */
30731 bool
30733 {
30736 /* We need to be able to tell '(r)' and 'r' apart (when it's of
30737 reference type). Only the latter is an id-expression. */
30745 }
30747 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
30748 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
30749 The CONTEXT determines the context in which auto deduction is performed
30750 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
30752 OUTER_TARGS is used during template argument deduction (context == adc_unify)
30753 to properly substitute the result. It's also used in the adc_unify and
30754 adc_requirement contexts to communicate the necessary template arguments
30755 to satisfaction. OUTER_TARGS is ignored in other contexts.
30757 Additionally for adc_unify contexts TMPL is the template for which TYPE
30758 is a template parameter type.
30760 For partial-concept-ids, extra args from OUTER_TARGS, TMPL and the current
30761 scope may be appended to the list of deduced template arguments prior to
30762 determining constraint satisfaction as appropriate. */
30764 tree
30771 {
30777 /* Defining a subset of type-dependent expressions that we can deduce
30778 from ahead of time isn't worth the trouble. */
30781 /* Similarly, we can't deduce from another undeduced decl. */
30785 /* We may be doing a partial substitution, but we still want to replace
30786 auto_node. */
30790 {
30791 /* We don't recurse here because we can't deduce from a nested
30792 initializer_list. */
30796 }
30800 /* In C++23, we must deduce the type to int&& for code like
30801 decltype(auto) f(int&& x) { return (x); }
30802 or
30803 auto&& f(int x) { return x; }
30804 so we use treat_lvalue_as_rvalue_p. But don't do it for
30805 decltype(auto) f(int x) { return x; }
30806 where we should deduce 'int' rather than 'int&&'; transmogrifying
30807 INIT to an rvalue would break that. */
30808 tree r;
30818 /* C++17 class template argument deduction. */
30822 /* Nothing we can do with this, even in deduction context. */
30827 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
30828 with either a new invented type template parameter U or, if the
30829 initializer is a braced-init-list (8.5.4), with
30830 std::initializer_list<U>. */
30832 {
30837 else
30838 {
30840 {
30844 "for deduction to %<std::initializer_list%>, use copy-"
30846 }
30848 }
30849 }
30854 tree targs;
30858 {
30859 /* [dcl.struct.bind]/1 - if decomposition declaration has no ref-qualifiers
30860 and initializer has array type, deduce cv-qualified array type. */
30863 }
30865 {
30873 }
30874 else
30875 {
30880 tree tparms;
30884 else
30885 {
30889 }
30893 DEDUCE_CALL,
30896 {
30898 /* Try again at instantiation time. */
30902 /* If type is error_mark_node a diagnostic must have been
30903 emitted by now. Also, having a mention to '<type error>'
30904 in the diagnostic is not really useful to the user. */
30905 {
30908 && (auto_node
30912 init);
30913 else
30916 DEDUCE_CALL,
30918 }
30920 }
30921 }
30923 /* Check any placeholder constraints against the deduced type. */
30927 {
30929 {
30934 /* If the constraint is dependent, we need to wait until
30935 instantiation time to resolve the placeholder. */
30938 }
30945 {
30949 {
30950 /* As in satisfy_declaration_constraints. */
30954 else
30956 }
30957 }
30964 /* HACK: Compensate for callers not always communicating all levels of
30965 outer template arguments by filling in the outermost missing levels
30966 with dummy levels before checking satisfaction. We'll still crash
30967 if the constraint depends on a template argument belonging to one of
30968 these missing levels, but this hack otherwise allows us to handle a
30969 large subset of possible constraints (including all non-dependent
30970 constraints). */
30973 {
30978 }
30981 {
30983 {
30984 auto_diagnostic_group d;
30986 {
31004 }
31006 }
31008 }
31009 }
31012 /* The outer template arguments are already substituted into type
31019 }
31021 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
31022 result. */
31024 tree
31026 {
31028 {
31031 }
31035 {
31036 /* In an abbreviated function template we didn't know we were dealing
31037 with a function template when we saw the auto return type, so rebuild
31038 the return type using an auto with the correct level. */
31043 auto_vec);
31044 /* Also rebuild the constraint info in terms of the new auto. */
31052 }
31054 }
31056 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
31057 'decltype(auto)' or a deduced class template. */
31059 bool
31061 {
31066 else
31068 }
31070 /* for_each_template_parm callback for type_uses_auto. */
31072 int
31074 {
31076 }
31078 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
31079 a use of `auto'. Returns NULL_TREE otherwise. */
31081 tree
31083 {
31087 {
31088 /* The Concepts TS allows multiple autos in one type-specifier; just
31089 return the first one we find, do_auto_deduction will collect all of
31090 them. */
31094 else
31096 }
31097 else
31099 }
31101 /* Report ill-formed occurrences of auto types in ARGUMENTS. If
31102 concepts are enabled, auto is acceptable in template arguments, but
31103 only when TEMPL identifies a template class. Return TRUE if any
31104 such errors were reported. */
31106 bool
31108 {
31110 /* Only the concepts TS allows 'auto' as a type-id; it'd otherwise
31111 have already been rejected by the parser more generally. */
31114 /* If there were previous errors, nevermind. */
31118 /* If TMPL is an identifier, we're parsing and we can't tell yet
31119 whether TMPL is supposed to be a type, a function or a variable.
31120 We'll only be able to tell during template substitution, so we
31121 expect to be called again then. If concepts are enabled and we
31122 know we have a type, we're ok. */
31129 /* Quickly search for any occurrences of auto; usually there won't
31130 be any, and then we'll avoid allocating the vector. */
31138 {
31143 }
31146 }
31148 /* Recursively walk over && expressions searching for EXPR. Return a reference
31149 to that expression. */
31152 {
31156 {
31161 }
31163 }
31165 /* Convert the generic type parameters in PARM that match the types given in the
31166 range [START_IDX, END_IDX) from the current_template_parms into generic type
31167 packs. */
31169 tree
31171 {
31182 {
31183 /* Create a distinct parameter pack type from the current parm and add it
31184 to the replacement args to tsubst below into the generic function
31185 parameter. */
31199 /* Replace the current template parameter with new pack. */
31202 /* Surgically adjust the associated constraint of adjusted parameter
31203 and it's corresponding contribution to the current template
31204 requirements. */
31206 {
31212 /* If there was a constraint, we also need to replace that in
31213 the template requirements, which we've already built. */
31217 }
31218 }
31224 /* If there are more levels then build up the replacement with the outer
31225 template parms. */
31229 replacement);
31232 }
31234 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
31235 0..N-1. */
31237 void
31239 {
31242 integer_type_node,
31243 NULL_TREE),
31247 CP_BUILT_IN_INTEGER_PACK);
31248 }
31250 /* Walk the decl or type specialization table calling FN on each
31251 entry. */
31253 void
31257 {
31263 }
31265 /* Lookup the specialization of *ELT, in the decl or type
31266 specialization table. Return the SPEC that's already there, or
31267 NULL if nothing. */
31269 tree
31271 {
31281 }
31283 /* Return flags encoding whether SPEC is on the instantiation and/or
31284 specialization lists of TMPL. */
31286 unsigned
31288 {
31294 {
31297 }
31302 /* Only need to search if DECL is a partial specialization. */
31306 {
31309 }
31312 }
31314 /* Add a new specialization described by SPEC. DECL is the
31315 maybe-template decl and FLAGS is as returned from
31316 get_mergeable_specialization_flags. */
31318 void
31321 {
31324 {
31333 {
31336 }
31337 }
31340 {
31343 /* We don't distinguish different constrained partial type
31344 specializations, so there could be duplicates. Everything else
31345 must be new. */
31347 {
31353 }
31354 }
31361 {
31362 /* A partial specialization. */
31367 }
31368 }
31370 /* Set up the hash tables for template instantiations. */
31372 void
31374 {
31380 }
31382 /* Print stats about the template hash tables for -fstats. */
31384 void
31386 {
31395 }
31397 #if CHECKING_P
31401 /* Verify that build_non_dependent_expr () works, for various expressions,
31402 and that location wrappers don't affect the results. */
31404 static void
31406 {
31409 /* Verify constants, without and with location wrappers. */
31426 }
31428 /* Verify that type_dependent_expression_p () works correctly, even
31429 in the presence of location wrapper nodes. */
31431 static void
31433 {
31438 /* If no templates are involved, nothing is type-dependent. */
31444 /* Within a template, an unresolved name is always type-dependent. */
31447 /* Ensure it copes with NULL_TREE and errors. */
31451 /* A USING_DECL in a template should be type-dependent, even if wrapped
31452 with a location wrapper (PR c++/83799). */
31461 }
31463 /* Run all of the selftests within this file. */
31465 void
31467 {
31470 }