| blob | 31e3e3910989b3678c55a556cfb763d216b30778 |
1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2022 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 };
227 /* Make the current scope suitable for access checking when we are
228 processing T. T can be FUNCTION_DECL for instantiated function
229 template, VAR_DECL for static member variable, or TYPE_DECL for
230 for a class or alias template (needed by instantiate_decl). */
232 void
234 {
246 /* An artificial deduction guide should have the same access as
247 the constructor. */
249 else
253 {
256 }
257 }
259 /* Restore the scope set up by push_access_scope. T is the node we
260 are processing. */
262 void
264 {
274 else
276 }
278 /* Do any processing required when DECL (a member template
279 declaration) is finished. Returns the TEMPLATE_DECL corresponding
280 to DECL, unless it is a specialization, in which case the DECL
281 itself is returned. */
283 tree
285 {
292 {
293 tree type;
301 {
305 }
307 }
312 {
314 {
317 }
318 else
320 }
321 else
326 }
328 /* Create a template info node. */
330 tree
332 {
337 }
339 /* Return the template info node corresponding to T, whatever T is. */
341 tree
343 {
365 }
367 /* Returns the template nesting level of the indicated class TYPE.
369 For example, in:
370 template <class T>
371 struct A
372 {
373 template <class U>
374 struct B {};
375 };
377 A<T>::B<U> has depth two, while A<T> has depth one.
378 Both A<T>::B<int> and A<int>::B<U> have depth one, if
379 they are instantiations, not specializations.
381 This function is guaranteed to return 0 if passed NULL_TREE so
382 that, for example, `template_class_depth (current_class_type)' is
383 always safe. */
385 int
387 {
391 {
401 {
404 else
406 }
409 else
411 }
414 }
416 /* Return TRUE if NODE instantiates a template that has arguments of
417 its own, be it directly a primary template or indirectly through a
418 partial specializations. */
419 static bool
421 {
433 /* So now we know we have a specialization, but it could be a full
434 or a partial specialization. To tell which, compare the depth of
435 its template arguments with those of its context. */
444 }
446 /* Subroutine of maybe_begin_member_template_processing.
447 Returns true if processing DECL needs us to push template parms. */
449 static bool
451 {
457 }
459 /* Subroutine of maybe_begin_member_template_processing.
460 Push the template parms in PARMS, starting from LEVELS steps into the
461 chain, and ending at the beginning, since template parms are listed
462 innermost first. */
464 static void
466 {
474 current_template_parms
480 NULL);
482 {
491 {
498 /* Push the CONST_DECL. */
504 }
505 }
506 }
508 /* Restore the template parameter context for a member template, a
509 friend template defined in a class definition, or a non-template
510 member of template class. */
512 void
514 {
515 tree parms;
520 {
523 /* Disregard full specializations (c++/60999). */
526 }
529 {
534 {
537 }
540 }
542 /* Remember how many levels of template parameters we pushed so that
543 we can pop them later. */
545 }
547 /* Undo the effects of maybe_begin_member_template_processing. */
549 void
551 {
560 {
564 }
565 }
567 /* Return a new template argument vector which contains all of ARGS,
568 but has as its innermost set of arguments the EXTRA_ARGS. */
570 tree
572 {
573 tree new_args;
591 }
593 /* Like add_to_template_args, but only the outermost ARGS are added to
594 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
595 (EXTRA_ARGS) levels are added. This function is used to combine
596 the template arguments from a partial instantiation with the
597 template arguments used to attain the full instantiation from the
598 partial instantiation.
600 If ARGS is a TEMPLATE_DECL, use its parameters as args. */
602 tree
604 {
605 tree new_args;
610 {
613 }
615 /* If there are more levels of EXTRA_ARGS than there are ARGS,
616 something very fishy is going on. */
619 /* If *all* the new arguments will be the EXTRA_ARGS, just return
620 them. */
624 /* For the moment, we make ARGS look like it contains fewer levels. */
629 /* Now, we restore ARGS to its full dimensions. */
633 }
635 /* Return the N levels of innermost template arguments from the ARGS. */
637 tree
639 {
640 tree new_args;
646 /* If N is 1, just return the innermost set of template arguments. */
650 /* If we're not removing anything, just return the arguments we were
651 given. */
657 /* Make a new set of arguments, not containing the outer arguments. */
664 }
666 /* The inverse of get_innermost_template_args: Return all but the innermost
667 EXTRA_LEVELS levels of template arguments from the ARGS. */
669 static tree
671 {
672 tree new_args;
678 /* If N is 1, just return the outermost set of template arguments. */
682 /* If we're not removing anything, just return the arguments we were
683 given. */
688 /* Make a new set of arguments, not containing the inner arguments. */
695 }
697 /* We've got a template header coming up; push to a new level for storing
698 the parms. */
700 void
702 {
703 /* We use a non-tag-transparent scope here, which causes pushtag to
704 put tags in this scope, rather than in the enclosing class or
705 namespace scope. This is the right thing, since we want
706 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
707 global template class, push_template_decl handles putting the
708 TEMPLATE_DECL into top-level scope. For a nested template class,
709 e.g.:
711 template <class T> struct S1 {
712 template <class T> struct S2 {};
713 };
715 pushtag contains special code to insert the TEMPLATE_DECL for S2
716 at the right scope. */
722 /* Add a dummy parameter level while we process the parameter list. */
723 current_template_parms
726 current_template_parms);
727 }
729 /* This routine is called when a specialization is declared. If it is
730 invalid to declare a specialization here, an error is reported and
731 false is returned, otherwise this routine will return true. */
733 static bool
735 {
738 /* [temp.expl.spec]
740 An explicit specialization shall be declared in the namespace of
741 which the template is a member, or, for member templates, in the
742 namespace of which the enclosing class or enclosing class
743 template is a member. An explicit specialization of a member
744 function, member class or static data member of a class template
745 shall be declared in the namespace of which the class template
746 is a member. */
748 {
751 }
753 /* [temp.expl.spec]
755 In an explicit specialization declaration for a member of a class
756 template or a member template that appears in namespace scope,
757 the member template and some of its enclosing class templates may
758 remain unspecialized, except that the declaration shall not
759 explicitly specialize a class member template if its enclosing
760 class templates are not explicitly specialized as well. */
762 {
765 }
768 }
770 /* We've just seen template <>. */
772 bool
774 {
778 }
780 /* Called at then end of processing a declaration preceded by
781 template<>. */
783 void
785 {
788 }
790 /* Any template <>'s that we have seen thus far are not referring to a
791 function specialization. */
793 void
795 {
798 }
800 /* We've just seen a template header. If SPECIALIZATION is nonzero,
801 it was of the form template <>. */
803 static void
805 {
807 template_header_count++;
808 }
810 /* We're beginning an explicit instantiation. */
812 void
814 {
817 }
820 void
822 {
825 }
827 /* An explicit specialization or partial specialization of TMPL is being
828 declared. Check that the namespace in which the specialization is
829 occurring is permissible. Returns false iff it is invalid to
830 specialize TMPL in the current namespace. */
832 static bool
834 {
837 /* [tmpl.expl.spec]
839 An explicit specialization shall be declared in a namespace enclosing the
840 specialized template. An explicit specialization whose declarator-id is
841 not qualified shall be declared in the nearest enclosing namespace of the
842 template, or, if the namespace is inline (7.3.1), any namespace from its
843 enclosing namespace set. */
846 {
849 }
852 /* Same or enclosing namespace. */
854 else
855 {
856 auto_diagnostic_group d;
862 }
863 }
865 /* SPEC is an explicit instantiation. Check that it is valid to
866 perform this explicit instantiation in the current namespace. */
868 static void
870 {
871 tree ns;
873 /* DR 275: An explicit instantiation shall appear in an enclosing
874 namespace of its template. */
880 }
882 /* Returns true if TYPE is a new partial specialization that needs to be
883 set up. This may also modify TYPE to point to the correct (new or
884 existing) constrained partial specialization. */
886 static bool
888 {
889 /* An implicit instantiation of an incomplete type implies
890 the definition of a new class template.
892 template<typename T>
893 struct S;
895 template<typename T>
896 struct S<T*>;
898 Here, S<T*> is an implicit instantiation of S whose type
899 is incomplete. */
903 /* It can also be the case that TYPE is a completed specialization.
904 Continuing the previous example, suppose we also declare:
906 template<typename T>
907 requires Integral<T>
908 struct S<T*>;
910 Here, S<T*> refers to the specialization S<T*> defined
911 above. However, we need to differentiate definitions because
912 we intend to define a new partial specialization. In this case,
913 we rely on the fact that the constraints are different for
914 this declaration than that above.
916 Note that we also get here for injected class names and
917 late-parsed template definitions. We must ensure that we
918 do not create new type declarations for those cases. */
920 {
924 /* If there are no template parameters, this cannot be a new
925 partial template specialization? */
929 /* The injected-class-name is not a new partial specialization. */
933 /* If the constraints are not the same as those of the primary
934 then, we can probably create a new specialization. */
938 {
942 }
944 /* Also, if there's a pre-existing specialization with matching
945 constraints, then this also isn't new. */
948 {
954 {
957 }
959 }
961 /* Create a new type node (and corresponding type decl)
962 for the newly declared specialization. */
967 /* We only need a separate type node for storing the definition of this
968 partial specialization; uses of S<T*> are unconstrained, so all are
969 equivalent. So keep TYPE_CANONICAL the same. */
972 /* Build the corresponding type decl. */
984 }
987 }
989 /* The TYPE is being declared. If it is a template type, that means it
990 is a partial specialization. Do appropriate error-checking. */
992 tree
994 {
995 tree context;
1000 /* A lambda that appears in specialization context is not itself a
1001 specialization. */
1005 /* An injected-class-name is not a specialization. */
1010 {
1014 }
1019 {
1025 else
1028 }
1030 {
1031 /* This is for ordinary explicit specialization and partial
1032 specialization of a template class such as:
1034 template <> class C<int>;
1036 or:
1038 template <class T> class C<T*>;
1040 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
1043 {
1050 {
1055 }
1056 }
1062 /* Trying to define a specialization either without a template<> header
1063 or in an inappropriate place. We've already given an error, so just
1064 bail now so we don't actually define the specialization. */
1066 }
1072 {
1073 /* This is for an explicit specialization of member class
1074 template according to [temp.expl.spec/18]:
1076 template <> template <class U> class C<int>::D;
1078 The context `C<int>' must be an implicit instantiation.
1079 Otherwise this is just a member class template declared
1080 earlier like:
1082 template <> class C<int> { template <class U> class D; };
1083 template <> template <class U> class C<int>::D;
1085 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1086 while in the second case, `C<int>::D' is a primary template
1087 and `C<T>::D' may not exist. */
1091 {
1092 tree t;
1097 {
1100 type))
1103 }
1105 /* Check for invalid specialization after instantiation:
1107 template <> template <> class C<int>::D<int>;
1108 template <> template <class U> class C<int>::D; */
1112 {
1116 {
1117 /* We already have a full specialization of this partial
1118 instantiation, or a full specialization has been
1119 looked up but not instantiated. Reassign it to the
1120 new member specialization template. */
1121 spec_entry elt;
1134 spec_entry **slot
1139 }
1140 else
1141 /* But if we've had an implicit instantiation, that's a
1142 problem ([temp.expl.spec]/6). */
1145 }
1147 /* Mark TYPE as a specialization. And as a result, we only
1148 have one level of template argument for the innermost
1149 class template. */
1154 }
1155 }
1157 {
1158 /* Someday C++0x may allow for enum template specialization. */
1163 else
1164 {
1167 }
1168 }
1171 }
1173 /* Returns nonzero if we can optimize the retrieval of specializations
1174 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1175 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1179 {
1182 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1183 parameter. */
1185 /* The optimized lookup depends on the fact that the
1186 template arguments for the member function template apply
1187 purely to the containing class, which is not true if the
1188 containing class is an explicit or partial
1189 specialization. */
1193 /* It is possible to have a template that is not a member
1194 template and is not a member of a template class:
1196 template <typename T>
1197 struct S { friend A::f(); };
1199 Here, the friend function is a template, but the context does
1200 not have template information. The optimized lookup relies
1201 on having ARGS be the template arguments for both the class
1202 and the function template. */
1204 }
1206 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1207 gone through coerce_template_parms by now. */
1209 static void
1211 {
1213 {
1222 /* Allow typedefs on the type of a non-type argument, since a
1224 else
1226 }
1227 }
1229 static void
1231 {
1236 }
1238 /* Retrieve the specialization (in the sense of [temp.spec] - a
1239 specialization is either an instantiation or an explicit
1240 specialization) of TMPL for the given template ARGS. If there is
1241 no such specialization, return NULL_TREE. The ARGS are a vector of
1242 arguments, or a vector of vectors of arguments, in the case of
1243 templates with more than one level of parameters.
1245 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1246 then we search for a partial specialization matching ARGS. This
1247 parameter is ignored if TMPL is not a class template.
1249 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1250 result is a NONTYPE_ARGUMENT_PACK. */
1252 static tree
1254 {
1264 /* There should be as many levels of arguments as there are
1265 levels of parameters. */
1274 /* Lambda functions in templates aren't instantiated normally, but through
1275 tsubst_lambda_expr. */
1280 {
1281 /* The template arguments actually apply to the containing
1282 class. Find the class specialization with those
1283 arguments. */
1285 tree class_specialization
1290 /* Find the instance of TMPL. */
1293 {
1297 /* using-declarations can bring in a different
1298 instantiation of tmpl as a member of a different
1299 instantiation of tmpl's class. We don't want those
1300 here. */
1303 }
1305 }
1306 else
1307 {
1309 spec_entry elt;
1318 else
1326 }
1329 }
1331 /* Like retrieve_specialization, but for local declarations. */
1333 tree
1335 {
1341 }
1343 /* Returns nonzero iff DECL is a specialization of TMPL. */
1345 int
1347 {
1348 tree t;
1351 {
1357 }
1358 else
1359 {
1368 }
1371 }
1373 /* Returns nonzero iff DECL is a specialization of friend declaration
1374 FRIEND_DECL according to [temp.friend]. */
1376 bool
1378 {
1385 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1386 of a template class, we want to check if DECL is a specialization
1387 if this. */
1391 {
1392 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1395 }
1400 /* There is nothing to do if this is not a template friend. */
1407 /* [temp.friend/6]
1408 A member of a class template may be declared to be a friend of a
1409 non-template class. In this case, the corresponding member of
1410 every specialization of the class template is a friend of the
1411 class granting friendship.
1413 For example, given a template friend declaration
1415 template <class T> friend void A<T>::f();
1417 the member function below is considered a friend
1419 template <> struct A<int> {
1420 void f();
1421 };
1423 For this type of template friend, TEMPLATE_DEPTH below will be
1424 nonzero. To determine if DECL is a friend of FRIEND, we first
1425 check if the enclosing class is a specialization of another. */
1432 {
1433 /* Next, we check the members themselves. In order to handle
1434 a few tricky cases, such as when FRIEND_DECL's are
1436 template <class T> friend void A<T>::g(T t);
1437 template <class T> template <T t> friend void A<T>::h();
1439 and DECL's are
1441 void A<int>::g(int);
1442 template <int> void A<int>::h();
1444 we need to figure out ARGS, the template arguments from
1445 the context of DECL. This is required for template substitution
1446 of `T' in the function parameter of `g' and template parameter
1447 of `h' in the above examples. Here ARGS corresponds to `int'. */
1454 {
1456 {
1459 else
1461 current_depth++;
1462 }
1464 }
1467 {
1469 tree friend_type;
1470 tree decl_type;
1471 tree friend_args_type;
1472 tree decl_args_type;
1474 /* Make sure that both DECL and FRIEND_DECL are templates or
1475 non-templates. */
1481 {
1482 /* If both are templates, check template parameter list. */
1483 tree friend_parms
1488 friend_parms))
1492 }
1493 else
1501 /* Check if return types match. */
1505 /* Check if function parameter types match, ignoring the
1506 `this' parameter. */
1515 }
1516 else
1517 {
1518 /* DECL is a TYPE_DECL */
1522 /* Make sure that both DECL and FRIEND_DECL are templates or
1523 non-templates. */
1524 is_template
1531 {
1532 tree friend_parms;
1533 /* If both are templates, check the name of the two
1534 TEMPLATE_DECL's first because is_friend didn't. */
1539 /* Now check template parameter list. */
1540 friend_parms
1543 return comp_template_parms
1545 friend_parms);
1546 }
1547 else
1550 }
1551 }
1553 }
1555 /* Register the specialization SPEC as a specialization of TMPL with
1556 the indicated ARGS. IS_FRIEND indicates whether the specialization
1557 is actually just a friend declaration. ATTRLIST is the list of
1558 attributes that the specialization is declared with or NULL when
1559 it isn't. Returns SPEC, or an equivalent prior declaration, if
1560 available.
1562 We also store instantiations of field packs in the hash table, even
1563 though they are not themselves templates, to make lookup easier. */
1565 static tree
1567 hashval_t hash)
1568 {
1569 tree fn;
1571 spec_entry elt;
1579 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1580 register it; we want the corresponding TEMPLATE_DECL instead.
1581 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1582 the more obvious `uses_template_parms (spec)' to avoid problems
1583 with default function arguments. In particular, given
1584 something like this:
1586 template <class T> void f(T t1, T t = T())
1588 the default argument expression is not substituted for in an
1589 instantiation unless and until it is actually needed. */
1593 /* We don't put these specializations in the hash table, but we might
1594 want to give an error about a mismatch. */
1596 else
1597 {
1608 else
1610 }
1612 /* We can sometimes try to re-register a specialization that we've
1613 already got. In particular, regenerate_decl_from_template calls
1614 duplicate_decls which will update the specialization list. But,
1615 we'll still get called again here anyhow. It's more convenient
1616 to simply allow this than to try to prevent it. */
1620 {
1622 {
1625 {
1627 fn);
1629 }
1630 else
1631 {
1632 tree clone;
1633 /* This situation should occur only if the first
1634 specialization is an implicit instantiation, the
1635 second is an explicit specialization, and the
1636 implicit instantiation has not yet been used. That
1637 situation can occur if we have implicitly
1638 instantiated a member function and then specialized
1639 it later.
1641 We can also wind up here if a friend declaration that
1642 looked like an instantiation turns out to be a
1643 specialization:
1645 template <class T> void foo(T);
1646 class S { friend void foo<>(int) };
1647 template <> void foo(int);
1649 We transform the existing DECL in place so that any
1650 pointers to it become pointers to the updated
1651 declaration.
1653 If there was a definition for the template, but not
1654 for the specialization, we want this to look as if
1655 there were no definition, and vice versa. */
1658 /* The call to duplicate_decls will have applied
1659 [temp.expl.spec]:
1661 An explicit specialization of a function template
1662 is inline only if it is explicitly declared to be,
1663 and independently of whether its function template
1664 is.
1666 to the primary function; now copy the inline bits to
1667 the various clones. */
1669 {
1676 }
1680 }
1681 }
1683 {
1686 /* We've already complained in duplicate_decls. */
1690 /* Dup decl failed, but this is a new definition. Set the
1691 line number so any errors match this new
1692 definition. */
1696 }
1697 }
1701 /* A specialization must be declared in the same namespace as the
1702 template it is specializing. */
1708 {
1717 /* If TMPL is a forward declaration of a template function, keep a list
1718 of all specializations in case we need to reassign them to a friend
1719 template later in tsubst_friend_function.
1721 Also keep a list of all variable template instantiations so that
1722 process_partial_specialization can check whether a later partial
1723 specialization would have used it. */
1726 }
1729 }
1731 /* Restricts tree and type comparisons. */
1735 /* Returns true iff two spec_entry nodes are equivalent. */
1737 bool
1739 {
1748 /* tmpl could be a FIELD_DECL for a capture pack. */
1752 {
1753 /* Partial specializations of a variable template can be distinguished by
1754 constraints. */
1758 }
1764 }
1766 /* Returns a hash for a template TMPL and template arguments ARGS. */
1768 static hashval_t
1770 {
1773 }
1775 hashval_t
1777 {
1782 }
1784 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1785 ignoring SPEC. */
1787 hashval_t
1789 {
1791 }
1793 /* Recursively calculate a hash value for a template argument ARG, for use
1794 in the hash tables of template specializations. We must be
1795 careful to (at least) skip the same entities template_args_equal
1796 does. */
1798 hashval_t
1800 {
1805 /* Strip nop-like things, but not the same as STRIP_NOPS. */
1816 {
1818 /* Getting here with an ARGUMENT_PACK_SELECT means we're probably
1819 preserving it in a hash table, which is bad because it will change
1820 meaning when gen_elem_of_pack_expansion_instantiation changes the
1821 ARGUMENT_PACK_SELECT_INDEX. */
1855 {
1858 {
1861 }
1863 }
1867 {
1870 }
1881 val = iterative_hash_template_arg
1893 val);
1895 val);
1904 /* [temp.over.link] Two lambda-expressions are never considered
1905 equivalent.
1907 So just hash the closure type. */
1918 /* Now hash operands as usual. */
1922 {
1925 {
1929 }
1931 call_expr_arg_iterator ai;
1936 }
1940 }
1944 {
1947 {
1948 // We want an alias specialization that survived strip_typedefs
1949 // to hash differently from its TYPE_CANONICAL, to avoid hash
1950 // collisions that compare as different in template_args_equal.
1951 // These could be dependent specializations that strip_typedefs
1952 // left alone, or untouched specializations because
1953 // coerce_template_parms returns the unconverted template
1954 // arguments if it sees incomplete argument packs.
1957 }
1960 {
1962 {
1965 /* Do not recurse with TPI directly, as that is unbounded
1966 recursion. */
1969 }
1978 {
1979 /* Hash the components that are relevant to TYPENAME_TYPE
1980 equivalence as determined by structural_comptypes. We
1981 can only coherently do this when comparing_specializations
1982 is set, because otherwise structural_comptypes tries
1983 resolving TYPENAME_TYPE via the current instantiation. */
1988 }
1995 }
2008 }
2009 }
2011 /* Unregister the specialization SPEC as a specialization of TMPL.
2012 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
2013 if the SPEC was listed as a specialization of TMPL.
2015 Note that SPEC has been ggc_freed, so we can't look inside it. */
2017 bool
2019 {
2021 spec_entry elt;
2029 {
2034 }
2037 }
2039 /* Like register_specialization, but for local declarations. We are
2040 registering SPEC, an instantiation of TMPL. */
2042 void
2044 {
2047 }
2049 /* TYPE is a class type. Returns true if TYPE is an explicitly
2050 specialized class. */
2052 bool
2054 {
2058 }
2060 /* Print the list of functions at FNS, going through all the overloads
2061 for each element of the list. Alternatively, FNS cannot be a
2062 TREE_LIST, in which case it will be printed together with all the
2063 overloads.
2065 MORE and *STR should respectively be FALSE and NULL when the function
2066 is called from the outside. They are used internally on recursive
2067 calls. print_candidates manages the two parameters and leaves NULL
2068 in *STR when it ends. */
2070 static void
2072 {
2076 else
2078 {
2084 {
2087 else
2090 }
2092 }
2093 }
2095 /* Print the list of candidate FNS in an error message. FNS can also
2096 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
2098 void
2100 {
2104 }
2106 /* Get a (possibly) constrained template declaration for the
2107 purpose of ordering candidates. */
2108 static tree
2110 {
2116 }
2118 /* Among candidates having the same signature, return the
2119 most constrained or NULL_TREE if there is no best candidate.
2120 If the signatures of candidates vary (e.g., template
2121 specialization vs. member function), then there can be no
2122 most constrained.
2124 Note that we don't compare constraints on the functions
2125 themselves, but rather those of their templates. */
2126 static tree
2128 {
2129 // Try to find the best candidate in a first pass.
2132 {
2139 }
2141 // Verify that the champ is better than previous candidates.
2146 }
2149 }
2152 /* Returns the template (one of the functions given by TEMPLATE_ID)
2153 which can be specialized to match the indicated DECL with the
2154 explicit template args given in TEMPLATE_ID. The DECL may be
2155 NULL_TREE if none is available. In that case, the functions in
2156 TEMPLATE_ID are non-members.
2158 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2159 specialization of a member template.
2161 The TEMPLATE_COUNT is the number of references to qualifying
2162 template classes that appeared in the name of the function. See
2163 check_explicit_specialization for a more accurate description.
2165 TSK indicates what kind of template declaration (if any) is being
2166 declared. TSK_TEMPLATE indicates that the declaration given by
2167 DECL, though a FUNCTION_DECL, has template parameters, and is
2168 therefore a template function.
2170 The template args (those explicitly specified and those deduced)
2171 are output in a newly created vector *TARGS_OUT.
2173 If it is impossible to determine the result, an error message is
2174 issued. The error_mark_node is returned to indicate failure. */
2176 static tree
2178 tree decl,
2182 tmpl_spec_kind tsk)
2183 {
2184 tree fns;
2185 tree targs;
2186 tree explicit_targs;
2189 /* A TREE_LIST of templates of which DECL may be a specialization.
2190 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2191 corresponding TREE_PURPOSE is the set of template arguments that,
2192 when used to instantiate the template, would produce a function
2193 with the signature of DECL. */
2203 /* We shouldn't be specializing a member template of an
2204 unspecialized class template; we already gave an error in
2205 check_specialization_scope, now avoid crashing. */
2209 {
2212 }
2220 /* Check for baselinks. */
2225 {
2229 }
2231 {
2234 }
2236 /* Count the number of template headers specified for this
2237 specialization. */
2248 {
2251 tf_warning_or_error,
2256 }
2258 {
2262 {
2263 tree decl_arg_types;
2264 tree fn_arg_types;
2266 /* In case of explicit specialization, we need to check if
2267 the number of template headers appearing in the specialization
2268 is correct. This is usually done in check_explicit_specialization,
2269 but the check done there cannot be exhaustive when specializing
2270 member functions. Consider the following code:
2272 template <> void A<int>::f(int);
2273 template <> template <> void A<int>::f(int);
2275 Assuming that A<int> is not itself an explicit specialization
2276 already, the first line specializes "f" which is a non-template
2277 member function, whilst the second line specializes "f" which
2278 is a template member function. So both lines are syntactically
2279 correct, and check_explicit_specialization does not reject
2280 them.
2282 Here, we can do better, as we are matching the specialization
2283 against the declarations. We count the number of template
2284 headers, and we check if they match TEMPLATE_COUNT + 1
2285 (TEMPLATE_COUNT is the number of qualifying template classes,
2286 plus there must be another header for the member template
2287 itself).
2289 Notice that if header_count is zero, this is not a
2290 specialization but rather a template instantiation, so there
2291 is no check we can perform here. */
2293 {
2296 }
2298 /* Check that the number of template arguments at the
2299 innermost level for DECL is the same as for FN. */
2307 /* DECL might be a specialization of FN. */
2311 /* For a non-static member function, we need to make sure
2312 that the const qualification is the same. Since
2313 get_bindings does not try to merge the "this" parameter,
2314 we must do the comparison explicitly. */
2316 {
2321 /* And the ref-qualification. */
2325 }
2327 /* Skip the "this" parameter and, for constructors of
2328 classes with virtual bases, the VTT parameter. A
2329 full specialization of a constructor will have a VTT
2330 parameter, but a template never will. */
2331 decl_arg_types
2333 fn_arg_types
2336 /* Function templates cannot be specializations; there are
2337 no partial specializations of functions. Therefore, if
2338 the type of DECL does not match FN, there is no
2339 match.
2341 Note that it should never be the case that we have both
2342 candidates added here, and for regular member functions
2343 below. */
2345 {
2347 current_template_parms))
2360 {
2361 /* C++20 CA104: Substitute directly into the
2362 constraint-expression. */
2368 }
2372 }
2374 /* See whether this function might be a specialization of this
2375 template. Suppress access control because we might be trying
2376 to make this specialization a friend, and we have already done
2377 access control for the declaration of the specialization. */
2383 /* We cannot deduce template arguments that when used to
2384 specialize TMPL will produce DECL. */
2388 /* We deduced something involving 'auto', which isn't a valid
2389 template argument. */
2392 /* Save this template, and the arguments deduced. */
2394 }
2396 /* FN is an ordinary member function, and we need a
2397 specialization of a member template. */
2398 ;
2400 /* We can get IDENTIFIER_NODEs here in certain erroneous
2401 cases. */
2402 ;
2404 /* This is just an ordinary non-member function. Nothing can
2405 be a specialization of that. */
2406 ;
2408 /* Cannot specialize functions that are created implicitly. */
2409 ;
2410 else
2411 {
2412 tree decl_arg_types;
2414 /* This is an ordinary member function. However, since
2415 we're here, we can assume its enclosing class is a
2416 template class. For example,
2418 template <typename T> struct S { void f(); };
2419 template <> void S<int>::f() {}
2421 Here, S<int>::f is a non-template, but S<int> is a
2422 template class. If FN has the same type as DECL, we
2423 might be in business. */
2426 /* Its enclosing class is an explicit specialization
2427 of a template class. This is not a candidate. */
2432 /* The return types differ. */
2435 /* Adjust the type of DECL in case FN is a static member. */
2442 decl_arg_types))
2450 // If the deduced arguments do not satisfy the constraints,
2451 // this is not a candidate.
2455 // Add the candidate.
2457 }
2458 }
2461 {
2462 /* We have:
2464 [temp.expl.spec]
2466 It is possible for a specialization with a given function
2467 signature to be instantiated from more than one function
2468 template. In such cases, explicit specification of the
2469 template arguments must be used to uniquely identify the
2470 function template specialization being specialized.
2472 Note that here, there's no suggestion that we're supposed to
2473 determine which of the candidate templates is most
2474 specialized. However, we, also have:
2476 [temp.func.order]
2478 Partial ordering of overloaded function template
2479 declarations is used in the following contexts to select
2480 the function template to which a function template
2481 specialization refers:
2483 -- when an explicit specialization refers to a function
2484 template.
2486 So, we do use the partial ordering rules, at least for now.
2487 This extension can only serve to make invalid programs valid,
2488 so it's safe. And, there is strong anecdotal evidence that
2489 the committee intended the partial ordering rules to apply;
2490 the EDG front end has that behavior, and John Spicer claims
2491 that the committee simply forgot to delete the wording in
2492 [temp.expl.spec]. */
2495 {
2498 }
2499 }
2501 // Concepts allows multiple declarations of member functions
2502 // with the same signature. Like above, we need to rely on
2503 // on the partial ordering of those candidates to determine which
2504 // is the best.
2506 {
2508 {
2511 }
2512 }
2515 {
2520 "saw %d %<template<>%>, need %d for "
2525 }
2529 {
2535 }
2537 /* We have one, and exactly one, match. */
2539 {
2543 /* Propagate the candidate's constraints to the declaration. */
2547 /* DECL is a re-declaration or partial instantiation of a template
2548 function. */
2551 /* It was a specialization of an ordinary member function in a
2552 template class. */
2554 }
2556 /* It was a specialization of a template. */
2559 {
2564 }
2565 else
2568 }
2570 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2571 but with the default argument values filled in from those in the
2572 TMPL_TYPES. */
2574 static tree
2576 tree tmpl_types)
2577 {
2578 tree new_spec_types;
2586 /* Substitute into the rest of the list. */
2587 new_spec_types =
2591 /* Add the default argument for this parameter. */
2594 new_spec_types);
2595 }
2597 /* DECL is an explicit specialization. Replicate default arguments
2598 from the template it specializes. (That way, code like:
2600 template <class T> void f(T = 3);
2601 template <> void f(double);
2602 void g () { f (); }
2604 works, as required.) An alternative approach would be to look up
2605 the correct default arguments at the call-site, but this approach
2606 is consistent with how implicit instantiations are handled. */
2608 static void
2610 {
2611 tree tmpl;
2612 tree spec_types;
2613 tree tmpl_types;
2614 tree new_spec_types;
2615 tree old_type;
2616 tree new_type;
2617 tree t;
2622 /* See if there's anything we need to do. */
2635 {
2636 /* Remove the this pointer, but remember the object's type for
2637 CV quals. */
2643 {
2644 /* DECL may contain more parameters than TMPL due to the extra
2645 in-charge parameter in constructors and destructors. */
2648 }
2650 {
2653 }
2654 }
2656 /* Compute the merged default arguments. */
2657 new_spec_types =
2660 /* Compute the new FUNCTION_TYPE. */
2662 {
2666 new_spec_types);
2669 /* Put the in-charge parameter back. */
2672 new_spec_types);
2676 new_spec_types);
2677 }
2678 else
2680 new_spec_types);
2686 }
2688 /* Return the number of template headers we expect to see for a definition
2689 or specialization of CTYPE or one of its non-template members. */
2691 int
2693 {
2697 {
2698 /* You're supposed to have one `template <...>' for every
2699 template class, but you don't need one for a full
2700 specialization. For example:
2702 template <class T> struct S{};
2703 template <> struct S<int> { void f(); };
2704 void S<int>::f () {}
2706 is correct; there shouldn't be a `template <>' for the
2707 definition of `S<int>::f'. */
2709 /* If CTYPE does not have template information of any
2710 kind, then it is not a template, nor is it nested
2711 within a template. */
2719 }
2722 }
2724 /* Do a simple sanity check on the template headers that precede the
2725 variable declaration DECL. */
2727 void
2729 {
2734 {
2737 "variable templates only available with "
2740 // Namespace-scope variable templates should have a template header.
2742 }
2744 {
2745 auto_diagnostic_group d;
2747 "too many template headers for %qD "
2753 "members of an explicitly specialized class are defined "
2755 }
2756 }
2758 /* An explicit specialization whose declarator-id or class-head-name is not
2759 qualified shall be declared in the nearest enclosing namespace of the
2760 template, or, if the namespace is inline (7.3.1), any namespace from its
2761 enclosing namespace set.
2763 If the name declared in the explicit instantiation is an unqualified name,
2764 the explicit instantiation shall appear in the namespace where its template
2765 is declared or, if that namespace is inline (7.3.1), any namespace from its
2766 enclosing namespace set. */
2768 void
2770 {
2775 {
2781 /* This was allowed in C++98, so only pedwarn. */
2783 "outside its namespace must use a nested-name-"
2785 }
2786 }
2788 /* Warn for a template specialization SPEC that is missing some of a set
2789 of function or type attributes that the template TEMPL is declared with.
2790 ATTRLIST is a list of additional attributes that SPEC should be taken
2791 to ultimately be declared with. */
2793 static void
2795 {
2799 /* Avoid warning if the difference between the primary and
2800 the specialization is not in one of the attributes below. */
2804 };
2806 /* Put together a list of the black listed attributes that the primary
2807 template is declared with that the specialization is not, in case
2808 it's not apparent from the most recent declaration of the primary. */
2809 pretty_printer str;
2816 auto_diagnostic_group d;
2819 spec))
2825 }
2827 /* Check to see if the function just declared, as indicated in
2828 DECLARATOR, and in DECL, is a specialization of a function
2829 template. We may also discover that the declaration is an explicit
2830 instantiation at this point.
2832 Returns DECL, or an equivalent declaration that should be used
2833 instead if all goes well. Issues an error message if something is
2834 amiss. Returns error_mark_node if the error is not easily
2835 recoverable.
2837 FLAGS is a bitmask consisting of the following flags:
2839 2: The function has a definition.
2840 4: The function is a friend.
2842 The TEMPLATE_COUNT is the number of references to qualifying
2843 template classes that appeared in the name of the function. For
2844 example, in
2846 template <class T> struct S { void f(); };
2847 void S<int>::f();
2849 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2850 classes are not counted in the TEMPLATE_COUNT, so that in
2852 template <class T> struct S {};
2853 template <> struct S<int> { void f(); }
2854 template <> void S<int>::f();
2856 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2857 invalid; there should be no template <>.)
2859 If the function is a specialization, it is marked as such via
2860 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2861 is set up correctly, and it is added to the list of specializations
2862 for that template. */
2864 tree
2866 tree decl,
2869 tree attrlist)
2870 {
2879 tmpl_spec_kind tsk;
2882 {
2885 else
2887 }
2888 else
2892 {
2895 {
2898 }
2902 {
2904 /* This could be something like:
2906 template <class T> void f(T);
2907 class S { friend void f<>(int); } */
2909 else
2910 {
2911 /* This case handles bogus declarations like template <>
2912 template <class T> void f<int>(); */
2916 declarator);
2918 }
2919 }
2923 /* The error has already been reported in
2924 check_specialization_scope. */
2930 /* Fall through. */
2943 decl);
2946 else
2950 /* Fall through. */
2956 /* In cases like template<> constexpr bool v = true;
2957 We'll give an error in check_template_variable. */
2963 else
2969 {
2970 /* This case handles bogus declarations like template <>
2971 template <class T> void f<int>(); */
2976 declarator);
2978 {
2979 /* Partial specialization of variable template. */
2983 }
2986 "non-type partial specialization %qE "
2988 else
2990 "non-class, non-variable partial specialization %qE "
2993 ok:;
2994 }
2997 /* This is a specialization of a member template, without
2998 specialization the containing class. Something like:
3000 template <class T> struct S {
3001 template <class U> void f (U);
3002 };
3003 template <> template <class U> void S<int>::f(U) {}
3005 That's a specialization -- but of the entire template. */
3011 }
3014 /* This doesn't apply to variable templates. */
3016 {
3020 {
3024 }
3025 }
3028 {
3034 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
3036 {
3037 tree fns;
3042 else
3043 {
3044 /* If there is no class context, the explicit instantiation
3045 must be at namespace scope. */
3048 /* Find the namespace binding, using the declaration
3049 context. */
3053 {
3054 /* If lookup fails, look for a friend declaration so we can
3055 give a better diagnostic. */
3056 fns = (lookup_qualified_name
3061 }
3064 {
3067 }
3068 }
3071 }
3077 {
3079 /* A specialization in class scope. This is invalid,
3080 but the error will already have been flagged by
3081 check_specialization_scope. */
3083 else
3084 {
3085 /* It's not valid to write an explicit instantiation in
3086 class scope, e.g.:
3088 class C { template void f(); }
3090 This case is caught by the parser. However, on
3091 something like:
3093 template class C { void f(); };
3095 (which is invalid) we can get here. The error will be
3096 issued later. */
3097 ;
3098 }
3101 }
3104 {
3105 // We'll match variable templates in start_decl.
3109 /* Find the list of functions in ctype that have the same
3110 name as the declared function. */
3114 {
3118 {
3119 /* From [temp.expl.spec]:
3121 If such an explicit specialization for the member
3122 of a class template names an implicitly-declared
3123 special member function (clause _special_), the
3124 program is ill-formed.
3126 Similar language is found in [temp.explicit]. */
3129 }
3132 }
3134 /* For a type-conversion operator, We might be looking for
3135 `operator int' which will be a specialization of
3136 `operator T'. Grab all the conversion operators, and
3137 then select from them. */
3142 {
3145 }
3146 else
3148 }
3150 /* Figure out what exactly is being specialized at this point.
3151 Note that for an explicit instantiation, even one for a
3152 member function, we cannot tell a priori whether the
3153 instantiation is for a member template, or just a member
3154 function of a template class. Even if a member template is
3155 being instantiated, the member template arguments may be
3156 elided if they can be deduced from the rest of the
3157 declaration. */
3160 member_specialization,
3161 template_count,
3162 tsk);
3165 /* We couldn't figure out what this declaration was
3166 specializing. */
3168 else
3169 {
3171 {
3172 auto_diagnostic_group d;
3174 "friend declaration %qD is not visible to "
3178 }
3187 {
3188 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3189 is done by do_decl_instantiation later. */
3195 {
3196 /* If TMPL is not the most general template (for
3197 example, if TMPL is a friend template that is
3198 injected into namespace scope), then there will
3199 be too many levels of TARGS. Remove some of them
3200 here. */
3202 tree new_targs;
3209 }
3212 }
3214 /* If we thought that the DECL was a member function, but it
3215 turns out to be specializing a static member function,
3216 make DECL a static member function as well. */
3222 /* If this is a specialization of a member template of a
3223 template class, we want to return the TEMPLATE_DECL, not
3224 the specialization of it. */
3226 {
3231 {
3232 tree parm;
3236 /* We want to use the argument list specified in the
3237 definition, not in the original declaration. */
3242 }
3245 }
3247 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3253 /* Inherit default function arguments from the template
3254 DECL is specializing. */
3258 /* This specialization has the same protection as the
3259 template it specializes. */
3263 /* 7.1.1-1 [dcl.stc]
3265 A storage-class-specifier shall not be specified in an
3266 explicit specialization...
3268 The parser rejects these, so unless action is taken here,
3269 explicit function specializations will always appear with
3270 global linkage.
3272 The action recommended by the C++ CWG in response to C++
3273 defect report 605 is to make the storage class and linkage
3274 of the explicit specialization match the templated function:
3276 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3277 */
3279 {
3283 /* A concept cannot be specialized. */
3285 {
3287 gen_tmpl);
3289 }
3291 /* This specialization has the same linkage and visibility as
3292 the function template it specializes. */
3295 {
3298 }
3301 {
3304 }
3305 }
3307 /* If DECL is a friend declaration, declared using an
3308 unqualified name, the namespace associated with DECL may
3309 have been set incorrectly. For example, in:
3311 template <typename T> void f(T);
3312 namespace N {
3313 struct S { friend void f<int>(int); }
3314 }
3316 we will have set the DECL_CONTEXT for the friend
3317 declaration to N, rather than to the global namespace. */
3322 /* This is not really a declaration of a specialization.
3323 It's just the name of an instantiation. But, it's not
3324 a request for an instantiation, either. */
3327 /* A specialization is not necessarily COMDAT. */
3333 /* If this is a full specialization, register it so that we can find
3334 it again. Partial specializations will be registered in
3335 process_partial_specialization. */
3337 {
3342 }
3345 /* A 'structor should already have clones. */
3351 }
3352 }
3355 }
3357 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3358 parameters. These are represented in the same format used for
3359 DECL_TEMPLATE_PARMS. */
3361 int
3363 {
3364 const_tree p1;
3365 const_tree p2;
3373 {
3385 {
3389 /* If either of the template parameters are invalid, assume
3390 they match for the sake of error recovery. */
3403 }
3404 }
3407 /* One set of parameters has more parameters lists than the
3408 other. */
3412 }
3414 /* Returns true if two template parameters are declared with
3415 equivalent constraints. */
3417 static bool
3419 {
3427 }
3429 /* Returns true when two template parameters are equivalent. */
3431 static bool
3433 {
3437 /* If either of the template parameters are invalid, assume
3438 they match for the sake of error recovery. */
3442 /* ... they declare parameters of the same kind. */
3446 /* ... one parameter was introduced by a parameter declaration, then
3447 both are. This case arises as a result of eagerly rewriting declarations
3448 during parsing. */
3452 /* ... if either declares a pack, they both do. */
3457 {
3458 /* ... if they declare non-type parameters, the types are equivalent. */
3461 }
3463 {
3464 /* ... if they declare template template parameters, their template
3465 parameter lists are equivalent. */
3468 }
3470 /* ... if they are declared with a qualified-concept name, they both
3471 are, and those names are equivalent. */
3473 }
3475 /* Returns true if two template parameters lists are equivalent.
3476 Two template parameter lists are equivalent if they have the
3477 same length and their corresponding parameters are equivalent.
3479 PARMS1 and PARMS2 are TREE_LISTs containing TREE_VECs: the
3480 data structure returned by DECL_TEMPLATE_PARMS.
3482 This is generally the same implementation as comp_template_parms
3483 except that it also the concept names and arguments used to
3484 introduce parameters. */
3486 static bool
3488 {
3495 {
3503 {
3508 }
3512 }
3518 }
3520 /* Return true if the requires-clause of the template parameter lists are
3521 equivalent and false otherwise. */
3522 static bool
3524 {
3532 }
3534 /* Returns true if two template heads are equivalent. 17.6.6.1p6:
3535 Two template heads are equivalent if their template parameter
3536 lists are equivalent and their requires clauses are equivalent.
3538 In pre-C++20, this is equivalent to calling comp_template_parms
3539 for the template parameters of TMPL1 and TMPL2. */
3541 bool
3543 {
3547 /* Don't change the matching rules for pre-C++20. */
3551 /* ... have the same number of template parameters, and their
3552 corresponding parameters are equivalent. */
3556 /* ... if either has a requires-clause, they both do and their
3557 corresponding constraint-expressions are equivalent. */
3559 }
3561 /* Determine whether PARM is a parameter pack. */
3563 bool
3565 {
3566 /* Determine if we have a non-type template parameter pack. */
3573 /* If this is a list of template parameters, we could get a
3574 TYPE_DECL or a TEMPLATE_DECL. */
3578 /* Otherwise it must be a type template parameter. */
3582 }
3584 /* Determine if T is a function parameter pack. */
3586 bool
3588 {
3592 }
3594 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3595 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3597 tree
3599 {
3606 }
3608 /* Return true iff the function parameter PARAM_DECL was expanded
3609 from the function parameter pack PACK. */
3611 bool
3613 {
3618 /* The parameter pack and its pack arguments have the same
3619 DECL_PARM_INDEX. */
3621 }
3623 /* Determine whether ARGS describes a variadic template args list,
3624 i.e., one that is terminated by a template argument pack. */
3626 static bool
3628 {
3630 tree last_parm;
3644 }
3646 /* Generate a new name for the parameter pack name NAME (an
3647 IDENTIFIER_NODE) that incorporates its */
3649 static tree
3651 {
3652 /* Munge the name to include the parameter index. */
3653 #define NUMBUF_LEN 128
3667 }
3669 /* Return true if T is a primary function, class or alias template
3670 specialization, not including the template pattern. */
3672 bool
3674 {
3690 }
3692 /* Return true if PARM is a template template parameter. */
3694 bool
3696 {
3698 }
3700 /* Return true iff PARM is a DECL representing a type template
3701 parameter. */
3703 bool
3705 {
3710 }
3712 /* Return the template parameters of T if T is a
3713 primary template instantiation, NULL otherwise. */
3715 tree
3717 {
3722 parms = INNERMOST_TEMPLATE_PARMS
3726 }
3728 /* Returns the template arguments of T if T is a template instantiation,
3729 NULL otherwise. */
3731 tree
3733 {
3741 }
3743 /* Return the argument pack elements of T if T is a template argument pack,
3744 NULL otherwise. */
3746 tree
3748 {
3754 }
3756 /* In an ARGUMENT_PACK_SELECT, the actual underlying argument that the
3757 ARGUMENT_PACK_SELECT represents. */
3759 static tree
3761 {
3765 /* If the selected argument is an expansion E, that most likely means we were
3766 called from gen_elem_of_pack_expansion_instantiation during the
3767 substituting of an argument pack (of which the Ith element is a pack
3768 expansion, where I is ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
3769 In this case, the Ith element resulting from this substituting is going to
3770 be a pack expansion, which pattern is the pattern of E. Let's return the
3771 pattern of E, and gen_elem_of_pack_expansion_instantiation will build the
3772 resulting pack expansion from it. */
3774 {
3775 /* Make sure we aren't throwing away arg info. */
3778 }
3781 }
3783 /* Return a modification of ARGS that's suitable for preserving inside a hash
3784 table. In particular, this replaces each ARGUMENT_PACK_SELECT with its
3785 underlying argument. ARGS is copied (upon modification) iff COW_P. */
3787 static tree
3789 {
3794 {
3796 tree r;
3803 else
3806 {
3808 {
3811 }
3813 }
3814 }
3817 }
3819 /* True iff FN is a function representing a built-in variadic parameter
3820 pack. */
3822 bool
3824 {
3834 }
3836 /* True iff CALL is a call to a function representing a built-in variadic
3837 parameter pack. */
3839 static bool
3841 {
3845 }
3847 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3849 static tree
3851 tree in_decl)
3852 {
3858 {
3860 {
3863 }
3868 }
3869 else
3870 {
3875 /* Calculate the largest value of len that won't make the size of the vec
3876 overflow an int. The compiler will exceed resource limits long before
3877 this, but it seems a decent place to diagnose. */
3881 {
3885 max);
3887 }
3895 }
3896 }
3898 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3899 CALL. */
3901 static tree
3903 tree in_decl)
3904 {
3914 }
3916 /* Return true if the tree T has the extra args mechanism for
3917 avoiding partial instantiation. */
3919 static bool
3921 {
3926 }
3928 /* Structure used to track the progress of find_parameter_packs_r. */
3929 struct find_parameter_pack_data
3930 {
3931 /* TREE_LIST that will contain all of the parameter packs found by
3932 the traversal. */
3935 /* Set of AST nodes that have been visited by the traversal. */
3938 /* True iff we're making a type pack expansion. */
3941 /* True iff we found a subtree that has the extra args mechanism. */
3943 };
3945 /* Identifies all of the argument packs that occur in a template
3946 argument and appends them to the TREE_LIST inside DATA, which is a
3947 find_parameter_pack_data structure. This is a subroutine of
3948 make_pack_expansion and uses_parameter_packs. */
3949 static tree
3951 {
3957 #define WALK_SUBTREE(NODE) \
3958 cp_walk_tree (&(NODE), &find_parameter_packs_r, \
3959 ppd, ppd->visited) \
3961 /* Don't look through typedefs; we are interested in whether a
3962 parameter pack is actually written in the expression/type we're
3963 looking at, not the target type. */
3965 {
3966 /* But do look at arguments for an alias template. */
3973 }
3975 /* Identify whether this is a parameter pack or not. */
3977 {
3985 /* FALLTHRU */
3987 /* If the placeholder appears in the decl-specifier-seq of a function
3988 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3989 is a pack expansion, the invented template parameter is a template
3990 parameter pack. */
4000 {
4001 /* We don't want to walk into the type of a PARM_DECL,
4002 because we don't want to see the type parameter pack. */
4005 }
4010 {
4011 /* We don't want to walk into the type of a variadic capture proxy,
4012 because we don't want to see the type parameter pack. */
4015 }
4017 {
4019 find_parameter_packs_r,
4022 }
4034 /* Not a parameter pack. */
4036 }
4039 {
4040 /* Add this parameter pack to the list. */
4042 }
4051 /* This switch statement will return immediately if we don't find a
4052 parameter pack. ??? Should some of these be in cp_walk_subtrees? */
4054 {
4056 /* Check the template itself. */
4062 {
4064 /* Ignore the declaration of a capture proxy for a parameter pack. */
4068 /* Since we stop at typedefs above, we need to look through them at
4069 the point of the DECL_EXPR. */
4073 }
4100 {
4101 /* Since we defer implicit capture, look in the parms and body. */
4108 }
4111 {
4112 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
4113 type_pack_expansion_p to false so that any placeholders
4114 within the expression don't get marked as parameter packs. */
4122 }
4131 /* Don't walk into IF_STMT_EXTRA_ARGS. */
4138 /* Local class, need to look through the whole definition. */
4142 else
4143 /* Enum, look at the values. */
4157 }
4159 #undef WALK_SUBTREE
4162 }
4164 /* Determines if the expression or type T uses any parameter packs. */
4165 tree
4167 {
4176 }
4178 /* Turn ARG, which may be an expression, type, or a TREE_LIST
4179 representation a base-class initializer into a parameter pack
4180 expansion. If all goes well, the resulting node will be an
4181 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
4182 respectively. */
4183 tree
4185 {
4186 tree result;
4195 {
4196 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
4197 class initializer. In this case, the TREE_PURPOSE will be a
4198 _TYPE node (representing the base class expansion we're
4199 initializing) and the TREE_VALUE will be a TREE_LIST
4200 containing the initialization arguments.
4202 The resulting expansion looks somewhat different from most
4203 expansions. Rather than returning just one _EXPANSION, we
4204 return a TREE_LIST whose TREE_PURPOSE is a
4205 TYPE_PACK_EXPANSION containing the bases that will be
4206 initialized. The TREE_VALUE will be identical to the
4207 original TREE_VALUE, which is a list of arguments that will
4208 be passed to each base. We do not introduce any new pack
4209 expansion nodes into the TREE_VALUE (although it is possible
4210 that some already exist), because the TREE_PURPOSE and
4211 TREE_VALUE all need to be expanded together with the same
4212 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
4213 resulting TREE_PURPOSE will mention the parameter packs in
4214 both the bases and the arguments to the bases. */
4215 tree purpose;
4216 tree value;
4219 /* Determine which parameter packs will be used by the base
4220 class expansion. */
4229 {
4232 arg);
4235 }
4238 {
4239 /* Collect the sets of parameter packs used in each of the
4240 initialization arguments. */
4242 {
4243 /* Determine which parameter packs will be expanded in this
4244 argument. */
4247 }
4248 }
4252 /* Create the pack expansion type for the base type. */
4258 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4259 they will rarely be compared to anything. */
4263 }
4268 /* Build the PACK_EXPANSION_* node. */
4269 result = for_types
4274 {
4275 /* Propagate type and const-expression information. */
4278 /* Mark this read now, since the expansion might be length 0. */
4280 }
4281 else
4282 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4283 they will rarely be compared to anything. */
4286 /* Determine which parameter packs will be expanded. */
4293 /* Make sure we found some parameter packs. */
4295 {
4297 {
4300 else
4302 }
4304 }
4309 /* If the pattern of this pack expansion contains a subtree that has
4310 the extra args mechanism for avoiding partial instantiation, then
4311 force this pack expansion to also use extra args. Otherwise
4312 partial instantiation of this pack expansion may not lower the
4313 level of some parameter packs within the pattern, which would
4314 confuse tsubst_pack_expansion later (PR101764). */
4318 }
4320 /* Checks T for any "bare" parameter packs, which have not yet been
4321 expanded, and issues an error if any are found. This operation can
4322 only be done on full expressions or types (e.g., an expression
4323 statement, "if" condition, etc.), because we could have expressions like:
4325 foo(f(g(h(args)))...)
4327 where "args" is a parameter pack. check_for_bare_parameter_packs
4328 should not be called for the subexpressions args, h(args),
4329 g(h(args)), or f(g(h(args))), because we would produce erroneous
4330 error messages.
4332 Returns TRUE and emits an error if there were bare parameter packs,
4333 returns FALSE otherwise. */
4334 bool
4336 {
4358 /* It's OK for a lambda to have an unexpanded parameter pack from the
4359 containing context, but do complain about unexpanded capture packs. */
4365 {
4366 /* We're in a lambda, but it isn't the innermost class.
4367 This should work, but currently doesn't. */
4370 }
4375 {
4381 }
4384 {
4387 {
4398 else
4403 else
4407 }
4410 }
4413 }
4415 /* Expand any parameter packs that occur in the template arguments in
4416 ARGS. */
4417 tree
4419 {
4428 /* First, determine if we need to expand anything, and the number of
4429 slots we'll need. */
4431 {
4436 {
4440 else
4442 }
4443 else
4444 {
4446 num_result_args++;
4447 }
4448 }
4450 /* If no expansion is necessary, we're done. */
4454 /* Expand arguments. */
4457 non_default_args_count =
4460 {
4463 {
4470 }
4471 else
4472 {
4475 }
4476 }
4480 }
4482 /* Checks if DECL shadows a template parameter.
4484 [temp.local]: A template-parameter shall not be redeclared within its
4485 scope (including nested scopes).
4487 Emits an error and returns TRUE if the DECL shadows a parameter,
4488 returns FALSE otherwise. */
4490 bool
4492 {
4493 tree olddecl;
4495 /* If we're not in a template, we can't possibly shadow a template
4496 parameter. */
4500 /* Figure out what we're shadowing. */
4504 /* If there's no previous binding for this name, we're not shadowing
4505 anything, let alone a template parameter. */
4509 /* If we're not shadowing a template parameter, we're done. Note
4510 that OLDDECL might be an OVERLOAD (or perhaps even an
4511 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4512 node. */
4516 /* We check for decl != olddecl to avoid bogus errors for using a
4517 name inside a class. We check TPFI to avoid duplicate errors for
4518 inline member templates. */
4524 /* Don't complain about the injected class name, as we've already
4525 complained about the class itself. */
4532 else
4537 }
4539 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4540 ORIG_LEVEL, DECL, and TYPE. */
4542 static tree
4546 tree decl,
4547 tree type)
4548 {
4559 }
4562 {
4564 {
4572 }
4575 {
4577 }
4578 };
4582 /* Find the canonical type parameter for the given template type
4583 parameter. Returns the canonical type parameter, which may be TYPE
4584 if no such parameter existed. */
4586 tree
4588 {
4596 }
4598 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4599 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4600 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4601 new one is created. */
4603 static tree
4605 tsubst_flags_t complain)
4606 {
4611 {
4616 type);
4631 /* Template template parameters need this. */
4634 {
4641 }
4643 /* Attach the TPI to the decl. */
4646 else
4648 }
4651 }
4653 /* Process information from new template parameter PARM and append it
4654 to the LIST being built. This new parameter is a non-type
4655 parameter iff IS_NON_TYPE is true. This new parameter is a
4656 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4657 is in PARM_LOC. */
4659 tree
4662 {
4668 {
4678 }
4685 {
4691 {
4692 /* [temp.param]
4694 The top-level cv-qualifiers on the template-parameter are
4695 ignored when determining its type. */
4700 && !is_parameter_pack
4701 /* If we're in a nested template parameter list, the template
4702 template parameter could be a parameter pack. */
4704 {
4705 /* This template parameter is not a parameter pack, but it
4706 should be. Complain about "bare" parameter packs. */
4709 /* Recover by calling this a parameter pack. */
4711 }
4712 }
4714 /* A template parameter is not modifiable. */
4723 current_template_depth,
4728 }
4729 else
4730 {
4731 tree t;
4735 {
4737 /* This is for distinguishing between real templates and template
4738 template parameters */
4741 /* any_template_parm_r expects to be able to get the targs of a
4742 DECL_TEMPLATE_RESULT. */
4751 }
4752 else
4753 {
4755 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4758 }
4765 current_template_depth,
4769 }
4773 /* Build requirements for the type/template parameter.
4774 This must be done after SET_DECL_TEMPLATE_PARM_P or
4775 process_template_parm could fail. */
4782 /* Build the parameter node linking the parameter declaration,
4783 its default argument (if any), and its constraints (if any). */
4789 else
4793 }
4795 /* The end of a template parameter list has been reached. Process the
4796 tree list into a parameter vector, converting each parameter into a more
4797 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4798 as PARM_DECLs. */
4800 tree
4802 {
4805 /* Pop the dummy parameter level and add the real one. We do not
4806 morph the dummy parameter in place, as it might have been
4807 captured by a (nested) template-template-parm. */
4810 current_template_parms
4815 {
4821 }
4826 }
4828 // Explicitly indicate the end of the template parameter list. We assume
4829 // that the current template parameters have been constructed and/or
4830 // managed explicitly, as when creating new template template parameters
4831 // from a shorthand constraint.
4832 void
4834 {
4836 }
4838 /* end_template_decl is called after a template declaration is seen. */
4840 void
4842 {
4848 /* This matches the pushlevel in begin_template_parm_list. */
4853 }
4855 /* Takes a TEMPLATE_PARM_P or DECL_TEMPLATE_PARM_P node or a TREE_LIST
4856 thereof, and converts it into an argument suitable to be passed to
4857 the type substitution functions. Note that if the TREE_LIST contains
4858 an error_mark node, the returned argument is error_mark_node. */
4860 tree
4862 {
4873 {
4877 else
4879 }
4885 {
4887 {
4888 /* Turn this argument into a TYPE_ARGUMENT_PACK
4889 with a single element, which expands T. */
4898 }
4899 }
4900 else
4901 {
4903 {
4904 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4905 with a single element, which expands T. */
4915 }
4916 else
4918 }
4920 }
4922 /* If T looks like a generic template argument produced by template_parm_to_arg,
4923 return the corresponding template parameter, otherwise return NULL_TREE. */
4925 static tree
4927 {
4932 {
4937 }
4944 else
4946 }
4948 /* Given a single level of template parameters (a TREE_VEC), return it
4949 as a set of template arguments. */
4951 tree
4953 {
4963 }
4965 /* Given a set of template parameters, return them as a set of template
4966 arguments. The template parameters are represented as a TREE_VEC, in
4967 the form documented in cp-tree.h for template arguments. */
4969 tree
4971 {
4972 tree header;
4977 /* If there is only one level of template parameters, we do not
4978 create a TREE_VEC of TREE_VECs. Instead, we return a single
4979 TREE_VEC containing the arguments. */
4984 {
4989 else
4991 }
4994 }
4996 /* Within the declaration of a template, return the currently active
4997 template parameters as an argument TREE_VEC. */
4999 static tree
5001 {
5003 }
5005 /* Return the fully generic arguments for of TMPL, i.e. what
5006 current_template_args would be while parsing it. */
5008 tree
5010 {
5015 /* DECL_TEMPLATE_RESULT doesn't have the arguments we want. For a template
5016 template parameter, it has no TEMPLATE_INFO; for a partial
5017 specialization, it has the arguments for the primary template, and we
5023 }
5025 /* Update the declared TYPE by doing any lookups which were thought to be
5026 dependent, but are not now that we know the SCOPE of the declarator. */
5028 tree
5030 {
5041 /* Don't bother building up the args in this case. */
5043 {
5044 /* tsubst in the args corresponding to the template parameters,
5045 including auto if present. Most things will be unchanged, but
5046 make_typename_type and tsubst_qualified_id will resolve
5047 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
5050 tree pushed;
5052 {
5056 }
5061 }
5067 {
5070 else
5072 }
5074 }
5076 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
5077 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
5078 the new template is a member template. */
5080 static tree
5082 {
5094 /* Propagate module information from the decl. */
5098 }
5100 struct template_parm_data
5101 {
5102 /* The level of the template parameters we are currently
5103 processing. */
5106 /* The index of the specialization argument we are currently
5107 processing. */
5110 /* An array whose size is the number of template parameters. The
5111 elements are nonzero if the parameter has been used in any one
5112 of the arguments processed so far. */
5115 /* An array whose size is the number of template arguments. The
5116 elements are nonzero if the argument makes use of template
5117 parameters of this level. */
5119 };
5121 /* Subroutine of push_template_decl used to see if each template
5122 parameter in a partial specialization is used in the explicit
5123 argument list. If T is of the LEVEL given in DATA (which is
5124 treated as a template_parm_data*), then DATA->PARMS is marked
5125 appropriately. */
5127 static int
5129 {
5137 {
5140 }
5142 /* In C++17 the type of a non-type argument is a deduced context. */
5147 data,
5148 NULL,
5151 /* Return zero so that for_each_template_parm will continue the
5152 traversal of the tree; we want to mark *every* template parm. */
5154 }
5156 /* Process the partial specialization DECL. */
5158 static tree
5160 {
5167 tree inner_parms;
5168 tree inst;
5178 /* A concept cannot be specialized. */
5180 {
5183 }
5188 /* We check that each of the template parameters given in the
5189 partial specialization is used in the argument list to the
5190 specialization. For example:
5192 template <class T> struct S;
5193 template <class T> struct S<T*>;
5195 The second declaration is OK because `T*' uses the template
5196 parameter T, whereas
5198 template <class T> struct S<int>;
5200 is no good. Even trickier is:
5202 template <class T>
5203 struct S1
5204 {
5205 template <class U>
5206 struct S2;
5207 template <class U>
5208 struct S2<T>;
5209 };
5211 The S2<T> declaration is actually invalid; it is a
5212 full-specialization. Of course,
5214 template <class U>
5215 struct S2<T (*)(U)>;
5217 or some such would have been OK. */
5225 {
5230 NULL,
5232 }
5235 {
5236 /* One of the template parms was not used in a deduced context in the
5237 specialization. */
5239 {
5243 }
5247 }
5252 /* [temp.class.spec]
5254 The argument list of the specialization shall not be identical to
5255 the implicit argument list of the primary template. */
5256 tree main_args
5259 && (!flag_concepts
5261 {
5264 "any template arguments; to define the primary template, "
5266 else
5268 "template arguments and is not more constrained than "
5269 "the primary template; to define the primary template, "
5272 }
5274 /* A partial specialization that replaces multiple parameters of the
5275 primary template with a pack expansion is less specialized for those
5276 parameters. */
5278 {
5280 "primary template because it replaces multiple parameters "
5283 /* Avoid crash in process_partial_specialization. */
5285 }
5288 {
5291 /* Avoid crash below. */
5293 }
5295 /* If we aren't in a dependent class, we can actually try deduction. */
5297 /* FIXME we should be able to handle a partial specialization of a
5298 partial instantiation, but currently we can't (c++/41727). */
5301 {
5302 auto_diagnostic_group d;
5305 decl))
5307 maintmpl);
5308 }
5310 /* [temp.spec.partial]
5312 The type of a template parameter corresponding to a specialized
5313 non-type argument shall not be dependent on a parameter of the
5314 specialization.
5316 Also, we verify that pack expansions only occur at the
5317 end of the argument list. */
5320 {
5327 {
5328 /* Extract the arguments from the argument pack. We'll be
5329 iterating over these in the following loop. */
5332 }
5335 {
5337 /* Get the Jth argument in the parameter pack. */
5341 {
5342 /* Pack expansions must come at the end of the
5343 argument list. */
5346 {
5350 else
5353 }
5354 }
5357 /* We only care about the pattern. */
5363 /* This next two lines are the `argument expression is not just a
5364 simple identifier' condition and also the `specialized
5365 non-type argument' bit. */
5370 {
5371 /* Look at the corresponding template parameter,
5372 marking which template parameters its type depends
5373 upon. */
5377 {
5378 /* We haven't yet initialized TPD2. Do so now. */
5380 /* The number of parameters here is the number in the
5381 main template, which, as checked in the assertion
5382 above, is NARGS. */
5386 }
5388 /* Mark the template parameters. But this time, we're
5389 looking for the template parameters of the main
5390 template, not in the specialization. */
5397 NULL,
5401 {
5402 /* The type depended on some template parameters.
5403 If they are fully specialized in the
5404 specialization, that's OK. */
5413 "type %qT of template argument %qE depends "
5415 "type %qT of template argument %qE depends "
5417 type,
5418 arg);
5419 }
5420 }
5421 }
5422 }
5424 /* We should only get here once. */
5428 // Build the template decl.
5435 /* Give template template parms a DECL_CONTEXT of the template
5436 for which they are a parameter. */
5438 {
5442 }
5445 /* We didn't register this in check_explicit_specialization so we could
5446 wait until the constraints were set. */
5448 else
5458 {
5464 {
5472 "declaration of %qD ambiguates earlier template "
5476 "partial specialization of %qD after instantiation "
5478 }
5479 }
5482 }
5484 /* PARM is a template parameter of some form; return the corresponding
5485 TEMPLATE_PARM_INDEX. */
5487 static tree
5489 {
5502 }
5504 /* Subroutine of fixed_parameter_pack_p below. Look for any template
5505 parameter packs used by the template parameter PARM. */
5507 static void
5509 {
5510 /* A type parm can't refer to another parm. */
5514 {
5518 }
5524 {
5528 else
5530 }
5531 }
5533 /* PARM is a template parameter pack. Return any parameter packs used in
5534 its type or the type of any of its template parameters. If there are
5535 any such packs, it will be instantiated into a fixed template parameter
5536 list by partial instantiation rather than be fully deduced. */
5538 tree
5540 {
5541 /* This can only be true in a member template. */
5544 /* This can only be true for a parameter pack. */
5547 /* A type parm can't refer to another parm. */
5561 }
5563 /* Check that a template declaration's use of default arguments and
5564 parameter packs is not invalid. Here, PARMS are the template
5565 parameters. IS_PRIMARY is true if DECL is the thing declared by
5566 a primary template. IS_PARTIAL is true if DECL is a partial
5567 specialization.
5569 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
5570 function template declaration or a friend class template
5571 declaration. In the function case, 1 indicates a declaration, 2
5572 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
5573 emitted for extraneous default arguments.
5575 Returns TRUE if there were no errors found, FALSE otherwise. */
5577 bool
5580 {
5583 tree parm_level;
5586 /* [temp.param]
5588 A default template-argument shall not be specified in a
5589 function template declaration or a function template definition, nor
5590 in the template-parameter-list of the definition of a member of a
5591 class template. */
5595 /* You can't have a function template declaration in a local
5596 scope, nor you can you define a member of a class template in a
5597 local scope. */
5605 /* A lambda doesn't have an explicit declaration; don't complain
5606 about the parms of the enclosing class. */
5613 /* If this is either a friend defined in the scope of the class
5614 or a member function. */
5620 /* And, if it was a member function, it really was defined in
5621 the scope of the class. */
5624 /* We already checked these parameters when the template was
5625 declared, so there's no need to do it again now. This function
5626 was defined in class scope, but we're processing its body now
5627 that the class is complete. */
5630 /* Core issue 226 (C++0x only): the following only applies to class
5631 templates. */
5634 {
5635 /* [temp.param]
5637 If a template-parameter has a default template-argument, all
5638 subsequent template-parameters shall have a default
5639 template-argument supplied. */
5641 {
5648 {
5658 {
5660 /* For better subsequent error-recovery, we indicate that
5661 there should have been a default argument. */
5664 }
5666 && !is_friend_decl
5667 /* Don't complain about an enclosing partial
5668 specialization. */
5673 /* A fixed parameter pack will be partially
5674 instantiated into a fixed length list. */
5676 {
5677 /* A primary class template, primary variable template
5678 (DR 2032), or alias template can only have one
5679 parameter pack, at the end of the template
5680 parameter list. */
5688 }
5689 }
5690 }
5691 }
5694 || is_partial
5695 || !is_primary
5697 /* For an ordinary class template, default template arguments are
5698 allowed at the innermost level, e.g.:
5699 template <class T = int>
5700 struct S {};
5701 but, in a partial specialization, they're not allowed even
5702 there, as we have in [temp.class.spec]:
5704 The template parameter list of a specialization shall not
5705 contain default template argument values.
5707 So, for a partial specialization, or for a function template
5708 (in C++98/C++03), we look at all of them. */
5709 ;
5710 else
5711 /* But, for a primary class template that is not a partial
5712 specialization we look at all template parameters except the
5713 innermost ones. */
5716 /* Figure out what error message to issue. */
5731 else
5732 /* Per [temp.param]/9, "A default template-argument shall not be
5733 specified in the template-parameter-lists of the definition of
5734 a member of a class template that appears outside of the member's
5735 class.", thus if we aren't handling a member of a class template
5736 there is no need to examine the parameters. */
5740 /* If we're inside a class definition, there's no need to
5741 examine the parameters to the class itself. On the one
5742 hand, they will be checked when the class is defined, and,
5743 on the other, default arguments are valid in things like:
5744 template <class T = double>
5745 struct S { template <class U> void f(U); };
5746 Here the default argument for `S' has no bearing on the
5747 declaration of `f'. */
5749 else
5750 /* Check everything. */
5756 {
5763 {
5768 {
5770 {
5777 }
5779 /* Clear out the default argument so that we are not
5780 confused later. */
5782 }
5783 }
5785 /* At this point, if we're still interested in issuing messages,
5786 they must apply to classes surrounding the object declared. */
5790 }
5793 }
5795 /* Worker for push_template_decl_real, called via
5796 for_each_template_parm. DATA is really an int, indicating the
5797 level of the parameters we are interested in. If T is a template
5798 parameter of that level, return nonzero. */
5800 static int
5802 {
5808 else
5811 }
5813 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5814 DATA is really an int, indicating the innermost outer level of parameters.
5815 If T is a template parameter of that level or further out, return
5816 nonzero. */
5818 static int
5820 {
5826 else
5829 }
5831 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5832 parameters given by current_template_args, or reuses a
5833 previously existing one, if appropriate. Returns the DECL, or an
5834 equivalent one, if it is replaced via a call to duplicate_decls.
5836 If IS_FRIEND is true, DECL is a friend declaration. */
5838 tree
5840 {
5844 /* See if this is a partial specialization. */
5853 /* No surprising friend functions. */
5858 tree ctx;
5860 /* For a friend, we want the context of the friend, not
5861 the type of which it is a friend. */
5865 /* In the case of a virtual function, we want the class in which
5866 it is defined. */
5868 else
5869 /* Otherwise, if we're currently defining some class, the DECL
5870 is assumed to be a member of the class. */
5879 /* See if this is a primary template. */
5883 /* A friend template that specifies a class context, i.e.
5884 template <typename T> friend void A<T>::f();
5885 is not primary. */
5886 ;
5888 /* Lambdas are not primary. */
5889 ;
5890 else
5893 /* True if the template is a member template, in the sense of
5894 [temp.mem]. */
5898 {
5906 {
5909 }
5911 {
5913 {
5916 }
5918 {
5919 /* [temp.mem]
5921 A destructor shall not be a member template. */
5925 }
5932 {
5933 /* [basic.stc.dynamic.allocation]
5935 An allocation function can be a function
5936 template. ... Template allocation functions shall
5937 have two or more parameters. */
5940 }
5941 }
5947 /* alias-declaration */
5953 else
5954 {
5957 }
5958 }
5965 /* Check to see that the rules regarding the use of default
5966 arguments are not being violated. We check args for a friend
5967 functions when we know whether it's a definition, introducing
5968 declaration or re-declaration. */
5973 /* Ensure that there are no parameter packs in the type of this
5974 declaration that have not been expanded. */
5976 {
5977 /* Check each of the arguments individually to see if there are
5978 any bare parameter packs. */
5984 {
5987 {
5988 /* This is a PARM_DECL that contains unexpanded parameter
5989 packs. We have already complained about this in the
5990 check_for_bare_parameter_packs call, so just replace
5991 these types with ERROR_MARK_NODE. */
5994 }
5998 }
6000 /* Check for bare parameter packs in the return type and the
6001 exception specifiers. */
6003 /* Errors were already issued, set return type to int
6004 as the frontend doesn't expect error_mark_node as
6005 the return type. */
6009 }
6010 else
6011 {
6015 {
6018 }
6023 }
6032 {
6033 /* Does not get a template head. */
6036 }
6043 {
6048 /* If DECL is a TYPE_DECL for a class-template, then there won't
6049 be DECL_LANG_SPECIFIC. The information equivalent to
6050 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
6054 {
6055 /* Since a template declaration already existed for this
6056 class-type, we must be redeclaring it here. Make sure
6057 that the redeclaration is valid. */
6059 current_template_parms,
6061 /* We don't need to create a new TEMPLATE_DECL; just use the
6062 one we already had. */
6064 }
6065 else
6066 {
6068 member_template_p);
6073 {
6074 /* A specialization of a member template of a template
6075 class. */
6079 }
6080 }
6081 }
6082 else
6083 {
6089 {
6092 }
6100 {
6101 /* The declaration is a specialization of a member
6102 template, declared outside the class. Therefore, the
6103 innermost template arguments will be NULL, so we
6104 replace them with the arguments determined by the
6105 earlier call to check_explicit_specialization. */
6108 tree new_tmpl
6110 member_template_p);
6118 args,
6121 }
6123 /* Make sure the template headers we got make sense. */
6128 {
6133 }
6134 else
6136 {
6141 {
6145 else
6149 /* Avoid crash in import_export_decl. */
6152 }
6157 /* Can happen in erroneous input. */
6159 else
6161 }
6163 /* Check that the parms are used in the appropriate qualifying scopes
6164 in the declarator. */
6168 {
6174 /* Avoid crash in import_export_decl. */
6177 }
6178 }
6183 {
6184 /* Push template declarations for global functions and types.
6185 Note that we do not try to push a global template friend
6186 declared in a template class; such a thing may well depend on
6187 the template parameters of the class and we'll push it when
6188 instantiating the befriending class. */
6191 {
6196 /* pushdecl may have found an existing template. */
6198 {
6201 }
6202 }
6204 {
6205 /* Record this decl as belonging to the current class. It's
6206 not chained onto anything else. */
6210 }
6211 }
6213 /* The type may have been completed, or (erroneously) changed. */
6217 {
6219 {
6224 /* Give template template parms a DECL_CONTEXT of the template
6225 for which they are a parameter. */
6228 {
6232 }
6236 {
6239 {
6240 /* ??? Why don't we do this here for all templates? */
6243 }
6246 }
6247 }
6249 /* The DECL_TI_ARGS of DECL contains full set of arguments
6250 referring wback to its most general template. If TMPL is a
6251 specialization, ARGS may only have the innermost set of
6252 arguments. Add the missing argument levels if necessary. */
6260 else
6261 {
6264 }
6265 }
6268 && !is_friend
6271 /* Set DECL_COMDAT on template instantiations; if we force
6272 them to be emitted by explicit instantiation,
6273 mark_needed will tell cgraph to do the right thing. */
6279 }
6281 /* FN is an inheriting constructor that inherits from the constructor
6282 template INHERITED; turn FN into a constructor template with a matching
6283 template header. */
6285 tree
6287 {
6288 tree inner_parms
6291 tree parms
6300 }
6302 /* Called when a class template TYPE is redeclared with the indicated
6303 template PARMS, e.g.:
6305 template <class T> struct S;
6306 template <class T> struct S {}; */
6308 bool
6310 {
6311 tree tmpl;
6312 tree tmpl_parms;
6316 {
6319 }
6323 /* The type is nested in some template class. Nothing to worry
6324 about here; there are no new template parameters for the nested
6325 type. */
6329 {
6331 tmpl);
6333 }
6339 {
6349 }
6352 {
6353 tree tmpl_parm;
6354 tree parm;
6366 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
6367 TEMPLATE_DECL. */
6377 {
6378 auto_diagnostic_group d;
6382 else
6385 }
6387 /* The parameters can be declared to introduce different
6388 constraints. */
6392 {
6393 auto_diagnostic_group d;
6399 }
6401 /* Give each template template parm in this redeclaration a
6402 DECL_CONTEXT of the template for which they are a parameter. */
6404 {
6407 }
6408 }
6417 /* Two classes with different constraints declare different entities. */
6419 {
6420 auto_diagnostic_group d;
6426 }
6429 }
6431 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
6432 to be used when the caller has already checked
6433 !instantiation_dependent_uneval_expression_p (expr)
6434 and cleared processing_template_decl. */
6436 tree
6438 {
6441 complain,
6445 }
6447 /* Instantiate the non-dependent expression EXPR. */
6449 tree
6451 {
6456 {
6457 /* The caller should have checked this already. */
6459 processing_template_decl_sentinel s;
6461 }
6463 }
6465 tree
6467 {
6469 }
6471 /* Like instantiate_non_dependent_expr, but return NULL_TREE if the
6472 expression is dependent or non-constant. */
6474 tree
6476 {
6480 {
6483 else
6484 {
6485 processing_template_decl_sentinel s;
6487 }
6488 }
6490 }
6492 /* True iff T is a specialization of a variable template. */
6494 bool
6496 {
6501 }
6503 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
6504 template declaration, or a TYPE_DECL for an alias declaration. */
6506 bool
6508 {
6516 }
6518 /* If T is a specialization of an alias template, return it; otherwise return
6519 NULL_TREE. If TRANSPARENT_TYPEDEFS is true, look through other aliases. */
6521 tree
6524 {
6528 /* It's an alias template specialization if it's an alias and its
6529 TYPE_NAME is a specialization of a primary template. */
6531 {
6538 transparent_typedefs);
6539 }
6542 }
6544 /* Data structure for complex_alias_template_*. */
6546 struct uses_all_template_parms_data
6547 {
6550 };
6552 /* walk_tree callback for complex_alias_template_p. */
6554 static tree
6556 {
6561 {
6566 {
6570 }
6573 }
6578 /* An alias template with a pack expansion that expands a pack from the
6579 enclosing class needs to be considered complex, to avoid confusion with
6580 the same pack being used as an argument to the alias's own template
6581 parameter (91966). */
6584 {
6593 /* Consider the expanded packs to be used outside the expansion... */
6595 }
6597 /* ...but don't walk into the pattern. Consider PR104008:
6599 template <typename T, typename... Ts>
6600 using IsOneOf = disjunction<is_same<T, Ts>...>;
6602 where IsOneOf seemingly uses all of its template parameters in its
6603 expansion (and does not expand a pack from the enclosing class), so the
6604 alias was not marked as complex. However, if it is used like
6605 "IsOneOf<T>", the empty pack for Ts means that T no longer appears in the
6606 expansion. So only Ts is considered used by the pack expansion. */
6610 }
6612 /* An alias template is complex from a SFINAE perspective if a template-id
6613 using that alias can be ill-formed when the expansion is not, as with
6614 the void_t template.
6616 Returns 1 if always complex, 0 if not complex, -1 if complex iff any of the
6617 template arguments are empty packs. */
6619 static bool
6621 {
6622 /* A renaming alias isn't complex. */
6626 /* Any other constrained alias is complex. */
6645 }
6647 /* If T is a specialization of a complex alias template with dependent
6648 template-arguments, return it; otherwise return NULL_TREE. If T is a
6649 typedef to such a specialization, return the specialization. */
6651 tree
6653 {
6664 && (any_dependent_template_arguments_p
6669 {
6672 }
6675 }
6677 /* Return the number of innermost template parameters in TMPL. */
6679 static int
6681 {
6684 }
6686 /* Return either TMPL or another template that it is equivalent to under DR
6687 1286: An alias that just changes the name of a template is equivalent to
6688 the other template. */
6690 static tree
6692 {
6695 {
6696 /* Determine if the alias is equivalent to an underlying template. */
6698 /* The underlying type may have been ill-formed. Don't proceed. */
6711 /* Does the alias add cv-quals? */
6719 /* Are any default template arguments equivalent? */
6724 {
6729 }
6731 /* If TMPL adds or changes any constraints, it isn't equivalent. I think
6732 it's appropriate to treat a less-constrained alias as equivalent. */
6736 /* Alias is equivalent. Strip it and repeat. */
6738 }
6739 top_break:;
6742 }
6744 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6745 must be a reference-to-function or a pointer-to-function type, as specified
6746 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6747 and check that the resulting function has external linkage. */
6749 static tree
6751 tsubst_flags_t complain)
6752 {
6755 linkage_kind linkage;
6773 /* [temp.arg.nontype]/1
6775 A template-argument for a non-type, non-template template-parameter
6776 shall be one of:
6777 [...]
6778 -- the address of an object or function with external [C++11: or
6779 internal] linkage. */
6783 {
6785 {
6792 else
6795 }
6797 }
6801 {
6803 {
6809 else
6813 }
6815 }
6817 accept:
6819 {
6822 else
6824 }
6829 }
6831 /* Subroutine of convert_nontype_argument.
6832 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6833 Emit an error otherwise. */
6835 static bool
6837 tsubst_flags_t complain)
6838 {
6854 {
6860 else
6862 }
6864 }
6866 /* Returns TRUE iff the address of OP is value-dependent.
6868 14.6.2.4 [temp.dep.temp]:
6869 A non-integral non-type template-argument is dependent if its type is
6870 dependent or it has either of the following forms
6871 qualified-id
6872 & qualified-id
6873 and contains a nested-name-specifier which specifies a class-name that
6874 names a dependent type.
6876 We generalize this to just say that the address of a member of a
6877 dependent class is value-dependent; the above doesn't cover the
6878 address of a static data member named with an unqualified-id. */
6880 static bool
6882 {
6885 /* We could use get_inner_reference here, but there's no need;
6886 this is only relevant for template non-type arguments, which
6887 can only be expressed as &id-expression. */
6889 {
6900 }
6903 }
6905 /* The next set of functions are used for providing helpful explanatory
6906 diagnostics for failed overload resolution. Their messages should be
6907 indented by two spaces for consistency with the messages in
6908 call.cc */
6910 static int
6912 {
6914 }
6916 /* Other failure functions should call this one, to provide a single function
6917 for setting a breakpoint on. */
6919 static int
6921 {
6923 }
6925 static int
6927 {
6932 }
6934 static int
6936 {
6942 }
6944 static int
6946 {
6950 }
6952 static int
6954 {
6957 " template parameter %qD is not a parameter pack, but "
6961 }
6963 static int
6965 {
6968 " template argument %qE does not match "
6972 }
6974 static int
6976 {
6980 }
6982 static int
6984 {
6990 }
6992 static int
6994 {
6996 {
7001 else
7003 " deduced conflicting values for non-type parameter "
7005 }
7007 }
7009 static int
7011 {
7014 " variable-sized array type %qT is not "
7016 arg);
7018 }
7020 static int
7022 {
7026 arg);
7028 }
7030 static int
7032 {
7034 {
7040 else
7045 }
7047 }
7049 static int
7051 {
7053 }
7055 static int
7058 {
7060 }
7062 static int
7065 {
7071 }
7073 static int
7076 {
7079 {
7087 }
7089 }
7091 static int
7093 {
7096 " template parameters of a template template argument are "
7099 }
7101 static int
7103 {
7109 }
7111 static int
7113 {
7118 }
7120 /* True if T is a C++20 template parameter object to store the argument for a
7121 template parameter of class type. */
7123 bool
7125 {
7128 }
7130 /* Subroutine of convert_nontype_argument, to check whether EXPR, as an
7131 argument for TYPE, points to an unsuitable object.
7133 Also adjust the type of the index in C++20 array subobject references. */
7135 static bool
7137 {
7139 {
7140 CASE_CONVERT:
7142 complain);
7146 complain);
7149 {
7153 }
7157 {
7163 {
7167 /* Canonicalize array offsets to ptrdiff_t; how they were
7168 written doesn't matter for subobject identity. */
7171 }
7174 {
7177 "%qE is not a valid template argument of type %qT "
7180 }
7182 {
7185 "%qE is not a valid template argument of type %qT "
7189 }
7192 {
7195 "%qE is not a valid template argument of type %qT "
7198 }
7199 /* C++17: For a non-type template-parameter of reference or pointer
7200 type, the value of the constant expression shall not refer to (or
7201 for a pointer type, shall not be the address of):
7202 * a subobject (4.5),
7203 * a temporary object (15.2),
7204 * a string literal (5.13.5),
7205 * the result of a typeid expression (8.2.8), or
7206 * a predefined __func__ variable (11.4.1). */
7208 {
7211 decl);
7213 }
7215 && !(same_type_ignoring_top_level_qualifiers_p
7218 {
7223 }
7225 {
7229 decl);
7231 }
7232 }
7240 else
7241 {
7243 {
7246 "because %qD is a variable, not the address of "
7249 }
7250 else
7251 {
7257 }
7258 }
7259 }
7262 }
7264 /* The template arguments corresponding to template parameter objects of types
7265 that contain pointers to members. */
7269 /* Return a VAR_DECL for the C++20 template parameter object corresponding to
7270 template argument EXPR. */
7272 static tree
7274 {
7279 {
7284 }
7288 /* This is no longer a compound literal. */
7307 {
7308 /* If EXPR contains any PTRMEM_CST, they will get clobbered by
7309 lower_var_init before we're done mangling. So store the original
7310 value elsewhere. */
7313 }
7318 }
7320 /* Return the actual template argument corresponding to template parameter
7321 object VAR. */
7323 tree
7325 {
7329 }
7331 /* Attempt to convert the non-type template parameter EXPR to the
7332 indicated TYPE. If the conversion is successful, return the
7333 converted value. If the conversion is unsuccessful, return
7334 NULL_TREE if we issued an error message, or error_mark_node if we
7335 did not. We issue error messages for out-and-out bad template
7336 parameters, but not simply because the conversion failed, since we
7337 might be just trying to do argument deduction. Both TYPE and EXPR
7338 must be non-dependent.
7340 The conversion follows the special rules described in
7341 [temp.arg.nontype], and it is much more strict than an implicit
7342 conversion.
7344 This function is called twice for each template argument (see
7345 lookup_template_class for a more accurate description of this
7346 problem). This means that we need to handle expressions which
7347 are not valid in a C++ source, but can be created from the
7348 first call (for instance, casts to perform conversions). These
7349 hacks can go away after we fix the double coercion problem. */
7351 static tree
7353 {
7354 tree expr_type;
7357 /* Detect immediately string literals as invalid non-type argument.
7358 This special-case is not needed for correctness (we would easily
7359 catch this later), but only to provide better diagnostic for this
7360 common user mistake. As suggested by DR 100, we do not mention
7361 linkage issues in the diagnostic as this is not the point. */
7363 {
7369 }
7371 /* Add the ADDR_EXPR now for the benefit of
7372 value_dependent_expression_p. */
7375 {
7379 }
7381 /* If we are in a template, EXPR may be non-dependent, but still
7382 have a syntactic, rather than semantic, form. For example, EXPR
7383 might be a SCOPE_REF, rather than the VAR_DECL to which the
7384 SCOPE_REF refers. Preserving the qualifying scope is necessary
7385 so that access checking can be performed when the template is
7386 instantiated -- but here we need the resolved form so that we can
7387 convert the argument. */
7399 /* If the argument is non-dependent, perform any conversions in
7400 non-dependent context as well. */
7408 else
7411 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
7412 to a non-type argument of "nullptr". */
7416 /* In C++11, integral or enumeration non-type template arguments can be
7417 arbitrary constant expressions. Pointer and pointer to
7418 member arguments can be general constant expressions that evaluate
7419 to a null value, but otherwise still need to be of a specific form. */
7421 {
7423 /* A PTRMEM_CST is already constant, and a valid template
7424 argument for a parameter of pointer to member type, we just want
7425 to leave it in that form rather than lower it to a
7429 {
7430 /* C++17: A template-argument for a non-type template-parameter shall
7431 be a converted constant expression (8.20) of the type of the
7432 template-parameter. */
7435 /* Make sure we return NULL_TREE only if we have really issued
7436 an error, as described above. */
7439 {
7442 }
7446 /* EXPR may have become value-dependent. */
7448 }
7450 {
7456 }
7457 }
7461 else
7464 /* HACK: Due to double coercion, we can get a
7465 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
7466 which is the tree that we built on the first call (see
7467 below when coercing to reference to object or to reference to
7468 function). We just strip everything and get to the arg.
7469 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
7470 for examples. */
7472 {
7473 /* Check this before we strip *& to avoid redundancy. */
7482 {
7483 /* ??? Maybe we could use convert_from_reference here, but we
7484 would need to relax its constraints because the NOP_EXPR
7485 could actually change the type to something more cv-qualified,
7486 and this is not folded by convert_from_reference. */
7491 && (same_type_ignoring_top_level_qualifiers_p
7494 {
7497 }
7498 }
7499 }
7501 /* [temp.arg.nontype]/5, bullet 1
7503 For a non-type template-parameter of integral or enumeration type,
7504 integral promotions (_conv.prom_) and integral conversions
7505 (_conv.integral_) are applied. */
7508 {
7510 {
7515 }
7520 /* Notice that there are constant expressions like '4 % 0' which
7521 do not fold into integer constants. */
7523 {
7525 {
7529 else
7535 /* else cxx_constant_value complained but gave us
7536 a real constant, so go ahead. */
7538 {
7539 /* Some assemble time constant expressions like
7540 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
7541 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
7542 as we can emit them into .rodata initializers of
7543 variables, yet they can't fold into an INTEGER_CST at
7544 compile time. Refuse them here. */
7549 }
7550 }
7551 else
7553 }
7555 /* Avoid typedef problems. */
7558 }
7559 /* [temp.arg.nontype]/5, bullet 2
7561 For a non-type template-parameter of type pointer to object,
7562 qualification conversions (_conv.qual_) and the array-to-pointer
7563 conversion (_conv.array_) are applied. */
7565 {
7568 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
7569 decay_conversion or an explicit cast. If it's a problematic cast,
7570 we'll complain about it below. */
7572 {
7577 {
7580 }
7581 }
7583 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
7585 A template-argument for a non-type, non-template template-parameter
7586 shall be one of: [...]
7588 -- the name of a non-type template-parameter;
7589 -- the address of an object or function with external linkage, [...]
7590 expressed as "& id-expression" where the & is optional if the name
7591 refers to a function or array, or if the corresponding
7592 template-parameter is a reference.
7594 Here, we do not care about functions, as they are invalid anyway
7595 for a parameter of type pointer-to-object. */
7598 /* Non-type template parameters are OK. */
7599 ;
7604 /* Other values, like integer constants, might be valid
7605 non-type arguments of some other type. */
7615 }
7616 /* [temp.arg.nontype]/5, bullet 3
7618 For a non-type template-parameter of type reference to object, no
7619 conversions apply. The type referred to by the reference may be more
7620 cv-qualified than the (otherwise identical) type of the
7621 template-argument. The template-parameter is bound directly to the
7622 template-argument, which must be an lvalue. */
7624 {
7626 expr_type))
7630 {
7635 }
7638 {
7643 }
7645 /* [temp.arg.nontype]/1
7647 A template-argument for a non-type, non-template template-parameter
7648 shall be one of: [...]
7650 -- the address of an object or function with external linkage. */
7653 {
7656 {
7659 "because a reference variable does not have a constant "
7662 }
7663 }
7666 /* OK, dependent reference. We don't want to ask whether a DECL is
7668 else
7669 {
7674 }
7678 }
7679 /* [temp.arg.nontype]/5, bullet 4
7681 For a non-type template-parameter of type pointer to function, only
7682 the function-to-pointer conversion (_conv.func_) is applied. If the
7683 template-argument represents a set of overloaded functions (or a
7684 pointer to such), the matching function is selected from the set
7685 (_over.over_). */
7687 {
7688 /* If the argument is a template-id, we might not have enough
7689 context information to decay the pointer. */
7691 {
7695 }
7698 /* Null pointer values are OK in C++11. */
7704 }
7705 /* [temp.arg.nontype]/5, bullet 5
7707 For a non-type template-parameter of type reference to function, no
7708 conversions apply. If the template-argument represents a set of
7709 overloaded functions, the matching function is selected from the set
7710 (_over.over_). */
7712 {
7714 {
7716 {
7721 }
7723 }
7728 }
7729 /* [temp.arg.nontype]/5, bullet 6
7731 For a non-type template-parameter of type pointer to member function,
7732 no conversions apply. If the template-argument represents a set of
7733 overloaded member functions, the matching member function is selected
7734 from the set (_over.over_). */
7736 {
7741 /* [temp.arg.nontype] bullet 1 says the pointer to member
7742 expression must be a pointer-to-member constant. */
7747 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
7748 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
7751 }
7752 /* [temp.arg.nontype]/5, bullet 7
7754 For a non-type template-parameter of type pointer to data member,
7755 qualification conversions (_conv.qual_) are applied. */
7757 {
7758 /* [temp.arg.nontype] bullet 1 says the pointer to member
7759 expression must be a pointer-to-member constant. */
7767 }
7769 {
7771 {
7776 }
7778 }
7780 {
7781 /* Replace the argument with a reference to the corresponding template
7782 parameter object. */
7787 }
7788 /* A template non-type parameter must be one of the above. */
7789 else
7792 /* Sanity check: did we actually convert the argument to the
7793 right type? */
7797 }
7799 /* Subroutine of coerce_template_template_parms, which returns 1 if
7800 PARM_PARM and ARG_PARM match using the rule for the template
7801 parameters of template template parameters. Both PARM and ARG are
7802 template parameters; the rest of the arguments are the same as for
7803 coerce_template_template_parms.
7804 */
7805 static int
7807 tree arg,
7808 tsubst_flags_t complain,
7809 tree in_decl,
7810 tree outer_args)
7811 {
7820 {
7822 /* We encounter instantiations of templates like
7823 template <template <template <class> class> class TT>
7824 class C; */
7825 {
7832 }
7833 /* Fall through. */
7838 /* Argument is a parameter pack but parameter is not. */
7843 /* The tsubst call is used to handle cases such as
7845 template <int> class C {};
7846 template <class T, template <T> class TT> class D {};
7847 D<int, C> d;
7849 i.e. the parameter list of TT depends on earlier parameters. */
7851 {
7856 }
7860 /* Argument is a parameter pack but parameter is not. */
7867 }
7870 }
7872 /* Coerce template argument list ARGLIST for use with template
7873 template-parameter TEMPL. */
7875 static tree
7877 tsubst_flags_t complain)
7878 {
7879 /* Consider an example where a template template parameter declared as
7881 template <class T, class U = std::allocator<T> > class TT
7883 The template parameter level of T and U are one level larger than
7884 of TT. To proper process the default argument of U, say when an
7885 instantiation `TT<int>' is seen, we need to build the full
7886 arguments containing {int} as the innermost level. Outer levels,
7887 available when not appearing as default template argument, can be
7888 obtained from the arguments of the enclosing template.
7890 Suppose that TT is later substituted with std::vector. The above
7891 instantiation is `TT<int, std::allocator<T> >' with TT at
7892 level 1, and T at level 2, while the template arguments at level 1
7893 becomes {std::vector} and the inner level 2 is {int}. */
7899 {
7900 /* This is an argument of the current template, so we haven't set
7901 DECL_CONTEXT yet. */
7902 tree relevant_template_parms;
7904 /* Parameter levels that are greater than the level of the given
7905 template template parm are irrelevant. */
7912 }
7919 complain,
7922 }
7924 /* A cache of template template parameters with match-all default
7925 arguments. */
7928 /* T is a bound template template-parameter. Copy its arguments into default
7929 arguments of the template template-parameter's template parameters. */
7931 static tree
7933 {
7956 {
7959 {
7962 }
7963 }
7967 }
7969 /* ARG is a bound potential template template-argument, and PARGS is a list
7970 of arguments for the corresponding template template-parameter. Adjust
7971 PARGS as appropriate for application to ARG's template, and if ARG is a
7972 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7973 arguments to the template template parameter. */
7975 static tree
7977 {
7981 {
7982 /* When comparing two template template-parameters in partial ordering,
7983 rewrite the one currently being used as an argument to have default
7984 arguments for all parameters. */
7990 }
7991 else
7992 {
7993 tree aparms
7998 }
8001 }
8003 /* Subroutine of unify for the case when PARM is a
8004 BOUND_TEMPLATE_TEMPLATE_PARM. */
8006 static int
8009 {
8013 /* The template template parm might be variadic and the argument
8014 not, so flatten both argument lists. */
8019 {
8020 /* In keeping with P0522R0, adjust P's template arguments
8021 to apply to A's template; then flatten it again. */
8029 /* If the P0522 adjustment eliminated a pack expansion, deduce
8030 empty packs. */
8036 }
8037 else
8038 {
8039 /* Deduce arguments T, i from TT<T> or TT<i>.
8040 We check each element of PARMVEC and ARGVEC individually
8041 rather than the whole TREE_VEC since they can have
8042 different number of elements, which is allowed under N2555. */
8046 /* Check if the parameters end in a pack, making them
8047 variadic. */
8054 /* If the template argument list of P contains a pack
8055 expansion that is not the last template argument, the
8056 entire template argument list is a non-deduced
8057 context. */
8075 DEDUCE_EXACT,
8078 }
8081 }
8083 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
8084 template template parameters. Both PARM_PARMS and ARG_PARMS are
8085 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
8086 or PARM_DECL.
8088 Consider the example:
8089 template <class T> class A;
8090 template<template <class U> class TT> class B;
8092 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
8093 the parameters to A, and OUTER_ARGS contains A. */
8095 static int
8097 tree arg_parms_full,
8098 tsubst_flags_t complain,
8099 tree in_decl,
8100 tree outer_args)
8101 {
8116 {
8117 /* P0522R0: A template template-parameter P is at least as specialized as
8118 a template template-argument A if, given the following rewrite to two
8119 function templates, the function template corresponding to P is at
8120 least as specialized as the function template corresponding to A
8121 according to the partial ordering rules for function templates
8122 ([temp.func.order]). Given an invented class template X with the
8123 template parameter list of A (including default arguments):
8125 * Each of the two function templates has the same template parameters,
8126 respectively, as P or A.
8128 * Each function template has a single function parameter whose type is
8129 a specialization of X with template arguments corresponding to the
8130 template parameters from the respective function template where, for
8131 each template parameter PP in the template parameter list of the
8132 function template, a corresponding template argument AA is formed. If
8133 PP declares a parameter pack, then AA is the pack expansion
8134 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
8136 If the rewrite produces an invalid type, then P is not at least as
8137 specialized as A. */
8139 /* So coerce P's args to apply to A's parms, and then deduce between A's
8140 args and the converted args. If that succeeds, A is at least as
8141 specialized as P, so they match.*/
8147 /* PARM, and thus the context in which we are passing ARG to it, may be
8148 at a deeper level than ARG; when trying to coerce to ARG_PARMS, we
8149 want to provide the right number of levels, so we reduce the number of
8150 levels in OUTER_ARGS before prepending them. This is most important
8151 when ARG is a namespace-scope template, as in alias-decl-ttp2.C.
8153 ARG might also be deeper than PARM (ttp23). In that case, we include
8154 all of OUTER_ARGS. The missing levels seem potentially problematic,
8155 but I can't come up with a testcase that breaks. */
8157 {
8162 }
8167 {
8173 }
8174 }
8176 /* Determine whether we have a parameter pack at the end of the
8177 template template parameter's template parameter list. */
8179 {
8186 {
8200 }
8201 }
8207 /* Check all of the template parameters except the parameter pack at
8208 the end (if any). */
8210 {
8219 outer_args))
8222 }
8225 {
8226 /* Check each of the template parameters in the template
8227 argument against the template parameter pack at the end of
8228 the template template parameter. */
8235 {
8242 outer_args))
8244 }
8245 }
8248 }
8250 /* Verifies that the deduced template arguments (in TARGS) for the
8251 template template parameters (in TPARMS) represent valid bindings,
8252 by comparing the template parameter list of each template argument
8253 to the template parameter list of its corresponding template
8254 template parameter, in accordance with DR150. This
8255 routine can only be called after all template arguments have been
8256 deduced. It will return TRUE if all of the template template
8257 parameter bindings are okay, FALSE otherwise. */
8258 bool
8260 {
8264 /* We're dealing with template parms in this process. */
8270 {
8275 {
8280 {
8281 /* Look inside the argument pack. */
8284 }
8287 {
8291 /* Extract the next argument from the argument
8292 pack. */
8296 /* Look at the pattern of the pack expansion. */
8299 /* Extract the template parameters from the template
8300 argument. */
8306 /* Verify that we can coerce the template template
8307 parameters from the template argument to the template
8308 parameter. This requires an exact match. */
8310 && !coerce_template_template_parms
8312 targ_parms,
8313 tf_none,
8314 tparm,
8315 targs))
8316 {
8319 }
8320 }
8321 }
8322 }
8324 out:
8328 }
8330 /* Since type attributes aren't mangled, we need to strip them from
8331 template type arguments. */
8333 tree
8335 {
8345 }
8347 /* And from inside dependent non-type arguments like sizeof(Type). */
8349 static tree
8351 {
8361 }
8363 /* A template declaration can be substituted for a constrained
8364 template template parameter only when the argument is no more
8365 constrained than the parameter. */
8367 static bool
8369 {
8372 /* For now, allow constrained template template arguments
8373 and unconstrained template template parameters. */
8377 /* If the template parameter is constrained, we need to rewrite its
8378 constraints in terms of the ARG's template parameters. This ensures
8379 that all of the template parameter types will have the same depth.
8381 Note that this is only valid when coerce_template_template_parm is
8382 true for the innermost template parameters of PARM and ARG. In other
8383 words, because coercion is successful, this conversion will be valid. */
8386 {
8395 }
8398 }
8400 // Convert a placeholder argument into a binding to the original
8401 // parameter. The original parameter is saved as the TREE_TYPE of
8402 // ARG.
8405 {
8408 }
8410 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
8411 because one of them is dependent. But we need to represent the
8412 conversion for the benefit of cp_tree_equal. */
8414 static tree
8416 {
8417 /* Auto parms get no conversion. */
8420 /* We don't need or want to add this conversion now if we're going to use the
8421 argument for deduction. */
8433 }
8435 /* Convert the indicated template ARG as necessary to match the
8436 indicated template PARM. Returns the converted ARG, or
8437 error_mark_node if the conversion was unsuccessful. Error and
8438 warning messages are issued under control of COMPLAIN. This
8439 conversion is for the Ith parameter in the parameter list. ARGS is
8440 the full set of template arguments deduced so far. */
8442 static tree
8444 tree arg,
8445 tree args,
8446 tsubst_flags_t complain,
8448 tree in_decl)
8449 {
8450 tree orig_arg;
8451 tree val;
8457 /* Trivially convert placeholders. */
8466 {
8467 /* The template argument was the name of some
8468 member function. That's usually
8469 invalid, but static members are OK. In any
8470 case, grab the underlying fields/functions
8471 and issue an error later if required. */
8473 }
8481 /* When determining whether an argument pack expansion is a template,
8482 look at the pattern. */
8486 /* Deal with an injected-class-name used as a template template arg. */
8488 {
8491 {
8501 }
8502 }
8504 is_tmpl_type =
8520 {
8522 {
8526 }
8529 "to refer to a type member of a template parameter, "
8534 typename_type,
8535 complain);
8538 }
8540 {
8542 {
8544 {
8549 {
8550 /* The template argument is a type, but we're expecting
8551 an expression. */
8556 /* [temp.arg]/2: "In a template-argument, an ambiguity
8557 between a type-id and an expression is resolved to a
8558 type-id, regardless of the form of the corresponding
8559 template-parameter." So give the user a clue. */
8562 "for non-type template parameter is treated as "
8564 }
8568 else
8571 }
8572 }
8574 }
8576 {
8578 {
8585 else
8588 }
8590 }
8593 /* We already did the appropriate conversion when packing args. */
8596 {
8598 {
8600 /* The number of argument required is not known yet.
8601 Just accept it for now. */
8603 else
8604 {
8606 tree argparm;
8608 /* Strip alias templates that are equivalent to another
8609 template. */
8615 args))
8616 {
8619 /* TEMPLATE_TEMPLATE_PARM node is preferred over
8620 TEMPLATE_DECL. */
8622 {
8627 }
8628 }
8629 else
8630 {
8632 {
8639 }
8642 }
8644 // Check that the constraints are compatible before allowing the
8645 // substitution.
8648 {
8650 {
8656 }
8658 }
8659 }
8660 }
8661 else
8663 /* We only form one instance of each template specialization.
8664 Therefore, if we use a non-canonical variant (i.e., a
8665 typedef), any future messages referring to the type will use
8666 the typedef, which is confusing if those future uses do not
8667 themselves also use the typedef. */
8670 }
8671 else
8672 {
8677 /* We don't have enough levels of args to do any substitution. This
8680 {
8682 LOOKUP_IMPLICIT);
8685 }
8686 else
8689 /* Perform array-to-pointer and function-to-pointer conversion
8690 as per [temp.param]/10. */
8696 /* Drop top-level cv-qualifiers on the substituted/deduced type of
8697 this non-type template parameter, as per [temp.param]/6. */
8705 /* We used to call digest_init here. However, digest_init
8706 will report errors, which we don't want when complain
8707 is zero. More importantly, digest_init will try too
8708 hard to convert things: for example, `0' should not be
8709 converted to pointer type at this point according to
8710 the standard. Accepting this is not merely an
8711 extension, since deciding whether or not these
8712 conversions can occur is part of determining which
8713 function template to call, or whether a given explicit
8714 argument specification is valid. */
8716 else
8717 {
8720 }
8731 {
8732 /* Reject template arguments that are references to built-in
8733 functions with no library fallbacks. */
8742 }
8745 {
8746 /* Strip typedefs from the SCOPE_REF. */
8749 complain);
8752 }
8753 }
8756 }
8758 /* Coerces the remaining template arguments in INNER_ARGS (from
8759 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
8760 Returns the coerced argument pack. PARM_IDX is the position of this
8761 parameter in the template parameter list. ARGS is the original
8762 template argument list. */
8763 static tree
8766 tree args,
8767 tree inner_args,
8769 tree new_args,
8771 tree in_decl,
8772 tsubst_flags_t complain)
8773 {
8776 tree packed_args;
8777 tree argument_pack;
8784 {
8785 /* When the template parameter is a non-type template parameter pack
8786 or template template parameter pack whose type or template
8787 parameters use parameter packs, we know exactly how many arguments
8788 we are looking for. Build a vector of the instantiated decls for
8789 these template parameters in PACKED_PARMS. */
8790 /* We can't use make_pack_expansion here because it would interpret a
8791 _DECL as a use rather than a declaration. */
8805 /* If we're doing a partial instantiation of a member template,
8806 verify that all of the types used for the non-type
8807 template parameter pack are, in fact, valid for non-type
8808 template parameters. */
8811 {
8814 {
8819 }
8820 /* We don't know how many args we have yet, just
8821 use the unconverted ones for now. */
8823 }
8826 }
8827 /* Check if we have a placeholder pack, which indicates we're
8828 in the context of a introduction list. In that case we want
8829 to match this pack to the single placeholder. */
8833 {
8836 }
8837 else
8840 /* Convert the remaining arguments, which will be a part of the
8841 parameter pack "parm". */
8844 {
8850 {
8851 /* Once we've packed as many args as we have types, stop. */
8855 /* We don't know how many args we have yet, just
8856 use the unconverted ones for now. */
8858 else
8860 }
8863 {
8866 }
8867 else
8870 in_decl);
8874 }
8878 {
8883 }
8888 else
8889 {
8892 }
8899 }
8901 /* Returns the number of pack expansions in the template argument vector
8902 ARGS. */
8904 static int
8906 {
8911 {
8915 }
8917 }
8919 /* Convert all template arguments to their appropriate types, and
8920 return a vector containing the innermost resulting template
8921 arguments. If any error occurs, return error_mark_node. Error and
8922 warning messages are issued under control of COMPLAIN.
8924 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8925 for arguments not specified in ARGS. Otherwise, if
8926 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
8927 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
8928 USE_DEFAULT_ARGS is false, then all arguments must be specified in
8929 ARGS. */
8931 static tree
8933 tree args,
8934 tree in_decl,
8935 tsubst_flags_t complain,
8938 {
8940 tree orig_inner_args;
8941 tree inner_args;
8942 tree new_args;
8943 tree new_inner_args;
8945 /* When used as a boolean value, indicates whether this is a
8946 variadic template parameter list. Since it's an int, we can also
8947 subtract it from nparms to get the number of non-variadic
8948 parameters. */
8953 /* Adjustment to nparms for fixed parameter packs. */
8958 /* Likewise for parameters with default arguments. */
8966 /* Determine if there are any parameter packs or default arguments. */
8968 {
8976 }
8979 /* If there are no parameters that follow a parameter pack, we need to
8980 expand any argument packs so that we can deduce a parameter pack from
8981 some non-packed args followed by an argument pack, as in variadic85.C.
8982 If there are such parameters, we need to leave argument packs intact
8983 so the arguments are assigned properly. This can happen when dealing
8984 with a nested class inside a partial specialization of a class
8985 template, as in variadic92.C, or when deducing a template parameter pack
8986 from a sub-declarator, as in variadic114.C. */
8990 /* Count any pack expansion args. */
8996 && require_all_args
8997 && !variadic_args_p
8998 && (!use_default_args
9001 {
9002 bad_nargs:
9004 {
9006 {
9010 }
9011 else
9018 }
9021 }
9022 /* We can't pass a pack expansion to a non-pack parameter of an alias
9023 template (DR 1430). */
9027 && variadic_args_p
9029 {
9031 {
9033 {
9039 {
9042 "pack expansion argument for non-pack parameter "
9044 else
9046 "pack expansion argument for non-pack parameter "
9050 }
9051 }
9053 found:;
9054 }
9056 }
9058 /* We need to evaluate the template arguments, even though this
9059 template-id may be nested within a "sizeof". */
9060 cp_evaluated ev;
9066 {
9067 tree arg;
9068 tree parm;
9070 /* Get the Ith template parameter. */
9074 {
9077 }
9079 /* Calculate the next argument. */
9082 else
9088 {
9089 /* Some arguments will be placed in the
9090 template parameter pack PARM. */
9097 {
9098 /* We don't know how many args we have yet, just use the
9099 unconverted (and still packed) ones for now. */
9103 }
9107 /* Store this argument. */
9109 {
9110 lost++;
9111 /* We are done with all of the arguments. */
9114 }
9115 else
9116 {
9120 {
9123 }
9124 }
9127 }
9129 {
9131 {
9132 /* "If every valid specialization of a variadic template
9133 requires an empty template parameter pack, the template is
9134 ill-formed, no diagnostic required." So check that the
9135 pattern works with this parameter. */
9140 in_decl);
9142 {
9147 }
9149 /* Recover from missing typename. */
9153 /* We don't know how many args we have yet, just
9154 use the unconverted ones for now. */
9158 }
9159 }
9161 {
9162 /* There must be a default arg in this case. */
9165 /* The position of the first default template argument,
9166 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
9167 Record that. */
9171 }
9172 else
9176 {
9179 }
9181 {
9182 /* This can occur if there was an error in the template
9183 parameter list itself (which we would already have
9184 reported) that we are trying to recover from, e.g., a class
9185 template with a parameter list such as
9186 template<typename..., typename> (cpp0x/variadic150.C). */
9189 /* This can also happen with a fixed parameter pack (71834). */
9192 }
9193 else
9199 lost++;
9202 }
9205 {
9206 /* If we had fixed parameter packs, we didn't know how many arguments we
9207 actually needed earlier; now we do. */
9211 }
9214 {
9215 /* We had some pack expansion arguments that will only work if the packs
9216 are empty, but wait until instantiation time to complain.
9217 See variadic-ttp3.C. */
9219 /* Except that we can't provide empty packs to alias templates or
9220 concepts when there are no corresponding parameters. Basically,
9221 we can get here with this:
9223 template<typename T> concept C = true;
9225 template<typename... Args>
9226 requires C<Args...>
9227 void f();
9229 When parsing C<Args...>, we try to form a concept check of
9230 C<?, Args...>. Without the extra check for substituting an empty
9231 pack past the last parameter, we can accept the check as valid.
9233 FIXME: This may be valid for alias templates (but I doubt it).
9235 FIXME: The error could be better also. */
9237 {
9242 }
9253 }
9256 {
9259 }
9266 }
9268 /* Convert all template arguments to their appropriate types, and
9269 return a vector containing the innermost resulting template
9270 arguments. If any error occurs, return error_mark_node. Error and
9271 warning messages are not issued.
9273 Note that no function argument deduction is performed, and default
9274 arguments are used to fill in unspecified arguments. */
9275 tree
9277 {
9279 }
9281 /* Convert all template arguments to their appropriate type, and
9282 instantiate default arguments as needed. This returns a vector
9283 containing the innermost resulting template arguments, or
9284 error_mark_node if unsuccessful. */
9285 tree
9287 tsubst_flags_t complain)
9288 {
9290 }
9292 /* Like coerce_template_parms. If PARMS represents all template
9293 parameters levels, this function returns a vector of vectors
9294 representing all the resulting argument levels. Note that in this
9295 case, only the innermost arguments are coerced because the
9296 outermost ones are supposed to have been coerced already.
9298 Otherwise, if PARMS represents only (the innermost) vector of
9299 parameters, this function returns a vector containing just the
9300 innermost resulting arguments. */
9302 static tree
9304 tree args,
9305 tree in_decl,
9306 tsubst_flags_t complain,
9309 {
9312 tree coerced_args;
9315 {
9317 tree level;
9323 {
9324 tree l;
9328 require_all_args,
9329 use_default_args);
9330 else
9337 }
9338 }
9339 else
9342 require_all_args,
9343 use_default_args);
9345 }
9347 /* Returns true if T is a wrapper to make a C++20 template parameter
9348 object const. */
9350 static bool
9352 {
9358 }
9360 /* Returns 1 if template args OT and NT are equivalent. */
9362 int
9364 {
9377 /* DR 1558: Don't treat an alias template specialization with dependent
9378 arguments as equivalent to its underlying type when used as a template
9379 argument; we need them to be distinct so that we substitute into the
9380 specialization arguments at instantiation time. And aliases can't be
9381 equivalent without being ==, so we don't need to look any deeper.
9383 During partial ordering, however, we need to treat them normally so we can
9384 order uses of the same alias with different cv-qualification (79960). */
9390 /* For member templates */
9403 {
9407 }
9408 else
9409 {
9410 /* Try to treat a template non-type argument that has been converted
9411 to the parameter type as equivalent to one that hasn't yet. */
9425 }
9426 }
9428 /* Returns true iff the OLDARGS and NEWARGS are in fact identical sets of
9429 template arguments. Returns false otherwise, and updates OLDARG_PTR and
9430 NEWARG_PTR with the offending arguments if they are non-NULL. */
9432 bool
9436 {
9447 {
9452 {
9458 }
9459 }
9461 }
9465 {
9467 }
9469 /* Implement a freelist interface for objects of type T.
9471 Head is a separate object, rather than a regular member, so that we
9472 can define it as a GTY deletable pointer, which is highly
9473 desirable. A data member could be declared that way, but then the
9474 containing object would implicitly get GTY((user)), which would
9475 prevent us from instantiating freelists as global objects.
9476 Although this way we can create freelist global objects, they're
9477 such thin wrappers that instantiating temporaries at every use
9478 loses nothing and saves permanent storage for the freelist object.
9480 Member functions next, anew, poison and reinit have default
9481 implementations that work for most of the types we're interested
9482 in, but if they don't work for some type, they should be explicitly
9483 specialized. See the comments before them for requirements, and
9484 the example specializations for the tree_list_freelist. */
9486 class freelist
9487 {
9488 /* Return the next object in a chain. We could just do type
9489 punning, but if we access the object with its underlying type, we
9490 avoid strict-aliasing trouble. This needs only work between
9491 poison and reinit. */
9494 /* Return a newly allocated, uninitialized or minimally-initialized
9495 object of type T. Any initialization performed by anew should
9496 either remain across the life of the object and the execution of
9497 poison, or be redone by reinit. */
9500 /* Optionally scribble all over the bits holding the object, so that
9501 they become (mostly?) uninitialized memory. This is called while
9502 preparing to make the object part of the free list. */
9507 #ifdef ENABLE_GC_CHECKING
9508 /* Poison the data, to indicate the data is garbage. */
9511 #endif
9512 /* Let valgrind know the object is free. */
9515 /* Let valgrind know the next portion of the object is available,
9516 but uninitialized. */
9518 }
9520 /* Bring an object that underwent at least one lifecycle after anew
9521 and before the most recent free and poison, back to a usable
9522 state, reinitializing whatever is needed for it to be
9523 functionally equivalent to an object just allocated and returned
9524 by anew. This may poison or clear the next field, used by
9525 freelist housekeeping after poison was called. */
9529 #ifdef ENABLE_GC_CHECKING
9531 #endif
9532 /* Let valgrind know the entire object is available, but
9533 uninitialized. */
9535 }
9537 /* Reference a GTY-deletable pointer that points to the first object
9538 in the free list proper. */
9541 /* Construct a freelist object chaining objects off of HEAD. */
9544 /* Add OBJ to the free object list. The former head becomes OBJ's
9545 successor. */
9547 {
9551 }
9553 /* Take an object from the free list, if one is available, or
9554 allocate a new one. Objects taken from the free list should be
9555 regarded as filled with garbage, except for bits that are
9556 configured to be preserved across free and alloc. */
9558 {
9560 {
9565 }
9566 else
9568 }
9569 };
9571 /* Explicitly specialize the interfaces for freelist<tree_node>: we
9572 want to allocate a TREE_LIST using the usual interface, and ensure
9573 TREE_CHAIN remains functional. Alas, we have to duplicate a bit of
9574 build_tree_list logic in reinit, so this could go out of sync. */
9578 {
9580 }
9582 inline tree
9584 {
9586 }
9590 {
9596 #ifdef ENABLE_GC_CHECKING
9599 /* Poison the data, to indicate the data is garbage. */
9602 #endif
9603 /* Let valgrind know the object is free. */
9605 /* But we still want to use the TREE_CODE and TREE_CHAIN parts. */
9609 #ifdef ENABLE_GC_CHECKING
9611 /* Keep TREE_CHAIN functional. */
9613 #else
9615 #endif
9616 }
9620 {
9623 #ifdef ENABLE_GC_CHECKING
9627 #endif
9629 /* Let valgrind know the entire object is available, but
9630 uninitialized. */
9633 #ifdef ENABLE_GC_CHECKING
9635 #else
9637 #endif
9638 }
9640 /* Point to the first object in the TREE_LIST freelist. */
9642 /* Return the/an actual TREE_LIST freelist. */
9645 {
9647 }
9649 /* Point to the first object in the tinst_level freelist. */
9651 /* Return the/an actual tinst_level freelist. */
9654 {
9656 }
9658 /* Point to the first object in the pending_template freelist. */
9660 /* Return the/an actual pending_template freelist. */
9663 {
9665 }
9667 /* Build the TREE_LIST object out of a split list, store it
9668 permanently, and return it. */
9669 tree
9671 {
9680 }
9684 /* Increment OBJ's refcount unless it is already infinite. */
9687 {
9691 }
9693 /* Release storage for OBJ and node, if it's a TREE_LIST. */
9694 void
9696 {
9700 }
9702 /* Decrement OBJ's refcount if not infinite. If it reaches zero, release
9703 OBJ's DECL and OBJ, and start over with the tinst_level object that
9704 used to be referenced by OBJ's NEXT. */
9705 static void
9707 {
9711 {
9715 }
9716 }
9718 /* Modify PTR so that it points to OBJ, adjusting the refcounts of OBJ
9719 and of the former PTR. Omitting the second argument is equivalent
9720 to passing (T*)NULL; this is allowed because passing the
9721 zero-valued integral constant NULL confuses type deduction and/or
9722 overload resolution. */
9724 static void
9726 {
9730 }
9732 static void
9734 {
9744 /* We are called both from instantiate_decl, where we've already had a
9745 tinst_level pushed, and instantiate_template, where we haven't.
9746 Compensate. */
9748 level = !current_tinst_level
9760 else
9769 }
9772 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
9773 ARGLIST. Valid choices for FNS are given in the cp-tree.def
9774 documentation for TEMPLATE_ID_EXPR. */
9776 tree
9778 {
9785 {
9788 }
9791 {
9794 unknown_type_node,
9796 arglist);
9798 }
9801 }
9803 /* Within the scope of a template class S<T>, the name S gets bound
9804 (in build_self_reference) to a TYPE_DECL for the class, not a
9805 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
9806 or one of its enclosing classes, and that type is a template,
9807 return the associated TEMPLATE_DECL. Otherwise, the original
9808 DECL is returned.
9810 Also handle the case when DECL is a TREE_LIST of ambiguous
9811 injected-class-names from different bases. */
9813 tree
9815 {
9819 /* DR 176: A lookup that finds an injected-class-name (10.2
9820 [class.member.lookup]) can result in an ambiguity in certain cases
9821 (for example, if it is found in more than one base class). If all of
9822 the injected-class-names that are found refer to specializations of
9823 the same class template, and if the name is followed by a
9824 template-argument-list, the reference refers to the class template
9825 itself and not a specialization thereof, and is not ambiguous. */
9827 {
9830 {
9836 }
9839 else
9841 }
9847 }
9849 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
9850 parameters, find the desired type.
9852 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
9854 IN_DECL, if non-NULL, is the template declaration we are trying to
9855 instantiate.
9857 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
9858 the class we are looking up.
9860 Issue error and warning messages under control of COMPLAIN.
9862 If the template class is really a local class in a template
9863 function, then the FUNCTION_CONTEXT is the function in which it is
9864 being instantiated.
9866 ??? Note that this function is currently called *twice* for each
9867 template-id: the first time from the parser, while creating the
9868 incomplete type (finish_template_type), and the second type during the
9869 real instantiation (instantiate_template_class). This is surely something
9870 that we want to avoid. It also causes some problems with argument
9871 coercion (see convert_nontype_argument for more information on this). */
9873 tree
9876 {
9880 tree t;
9883 spec_entry elt;
9884 hashval_t hash;
9887 {
9891 else
9892 {
9899 }
9900 }
9902 {
9905 /* If we are declaring a constructor, say A<T>::A<T>, we will get
9906 an implicit typename for the second A. Deal with it. */
9911 {
9914 }
9915 }
9918 {
9921 }
9923 {
9926 }
9928 {
9931 }
9933 /* Issue an error message if we didn't find a template. */
9935 {
9939 }
9942 /* Make sure it's a user visible template, if it was named by
9943 the user. */
9946 {
9948 {
9952 }
9954 }
9958 /* An alias that just changes the name of a template is equivalent to the
9959 other template, so if any of the arguments are pack expansions, strip
9960 the alias to avoid problems with a pack expansion passed to a non-pack
9961 alias template parameter (DR 1430). */
9966 {
9967 tree parm;
9976 }
9977 else
9978 {
9980 tree gen_tmpl;
9981 tree type_decl;
9989 /* An error occurred while building the template TEMPL, and a
9990 diagnostic has most certainly been emitted for that
9991 already. Let's propagate that error. */
10003 {
10004 /* We've been given an incomplete set of template arguments.
10005 For example, given:
10007 template <class T> struct S1 {
10008 template <class U> struct S2 {};
10009 template <class U> struct S2<U*> {};
10010 };
10012 we will be called with an ARGLIST of `U*', but the
10013 TEMPLATE will be `template <class T> template
10014 <class U> struct S1<T>::S2'. We must fill in the missing
10015 arguments. */
10019 }
10021 /* Now we should have enough arguments. */
10024 /* From here on, we're only interested in the most general
10025 template. */
10027 /* Shortcut looking up the current class scope again. */
10034 /* Calculate the BOUND_ARGS. These will be the args that are
10035 actually tsubst'd into the definition to create the
10036 instantiation. */
10038 complain,
10043 /* We were unable to bind the arguments. */
10046 /* In the scope of a template class, explicit references to the
10047 template class refer to the type of the template, not any
10048 instantiation of it. For example, in:
10050 template <class T> class C { void f(C<T>); }
10052 the `C<T>' is just the same as `C'. Outside of the
10053 class, however, such a reference is an instantiation. */
10057 {
10062 }
10064 /* If we already have this specialization, return it. */
10074 /* If the template's constraints are not satisfied,
10075 then we cannot form a valid type.
10077 Note that the check is deferred until after the hash
10078 lookup. This prevents redundant checks on previously
10079 instantiated specializations. */
10083 {
10085 {
10086 auto_diagnostic_group d;
10089 }
10091 }
10095 /* If the deduced arguments are invalid, then the binding
10096 failed. */
10100 complain))
10107 /* This occurs when the user has tried to define a tagged type
10108 in a scope that forbids it. We emitted an error during the
10109 parse. We didn't complete the bail out then, so here we
10110 are. */
10115 {
10117 /* If the context of the partially instantiated template is
10118 already non-dependent, then we might as well use it. */
10120 else
10121 {
10124 /* Try completing the enclosing context if it's not already so. */
10127 {
10130 {
10131 /* Completion could have caused us to register the desired
10132 specialization already, so check the table again. */
10136 }
10137 }
10138 }
10139 }
10140 else
10149 /* Create the type. */
10151 {
10152 /* The user referred to a specialization of an alias
10153 template represented by GEN_TMPL.
10155 [temp.alias]/2 says:
10157 When a template-id refers to the specialization of an
10158 alias template, it is equivalent to the associated
10159 type obtained by substitution of its
10160 template-arguments for the template-parameters in the
10161 type-id of the alias template. */
10164 /* Note that the call above (by indirectly calling
10165 register_specialization in tsubst_decl) registers the
10166 TYPE_DECL representing the specialization of the alias
10167 template. So next time someone substitutes ARGLIST for
10168 the template parms into the alias template (GEN_TMPL),
10169 she'll get that TYPE_DECL back. */
10173 }
10175 {
10177 {
10188 }
10189 else
10190 {
10191 /* We don't want to call start_enum for this type, since
10192 the values for the enumeration constants may involve
10193 template parameters. And, no one should be interested
10194 in the enumeration constants for such a type. */
10197 }
10201 }
10203 {
10204 /* Lambda closures are regenerated in tsubst_lambda_expr, not
10205 instantiated here. */
10213 /* A local class. Make sure the decl gets registered properly. */
10220 /* This instantiation is another name for the primary
10221 template type. Set the TYPE_CANONICAL field
10222 appropriately. */
10226 }
10227 else
10230 /* If we called start_enum or pushtag above, this information
10231 will already be set up. */
10234 {
10241 }
10244 /* Although GEN_TMPL is the TEMPLATE_DECL, it has the same value
10245 of export flag. We want to propagate this because it might
10246 be a friend declaration that pushes a new hidden binding. */
10250 {
10256 {
10259 }
10260 }
10264 {
10268 {
10269 tree attributes
10277 }
10278 }
10280 /* Let's consider the explicit specialization of a member
10281 of a class template specialization that is implicitly instantiated,
10282 e.g.:
10283 template<class T>
10284 struct S
10285 {
10286 template<class U> struct M {}; //#0
10287 };
10289 template<>
10290 template<>
10291 struct S<int>::M<char> //#1
10292 {
10293 int i;
10294 };
10295 [temp.expl.spec]/4 says this is valid.
10297 In this case, when we write:
10298 S<int>::M<char> m;
10300 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
10301 the one of #0.
10303 When we encounter #1, we want to store the partial instantiation
10304 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
10306 For all cases other than this "explicit specialization of member of a
10307 class template", we just want to store the most general template into
10308 the CLASSTYPE_TI_TEMPLATE of M.
10310 This case of "explicit specialization of member of a class template"
10311 only happens when:
10312 1/ the enclosing class is an instantiation of, and therefore not
10313 the same as, the context of the most general template, and
10314 2/ we aren't looking at the partial instantiation itself, i.e.
10315 the innermost arguments are not the same as the innermost parms of
10316 the most general template.
10318 So it's only when 1/ and 2/ happens that we want to use the partial
10319 instantiation of the member template in lieu of its most general
10320 template. */
10324 /* the enclosing class must be an instantiation... */
10327 {
10331 tree partial_inst_args =
10338 use_partial_inst_tmpl =
10339 /*...and we must not be looking at the partial instantiation
10340 itself. */
10342 partial_inst_args);
10343 }
10346 /* This case is easy; there are no member templates involved. */
10348 else
10349 {
10350 /* This is a full instantiation of a member template. Find
10351 the partial instantiation of which this is an instance. */
10353 /* Temporarily reduce by one the number of levels in the ARGLIST
10354 so as to avoid comparing the last set of arguments. */
10356 /* We don't use COMPLAIN in the following call because this isn't
10357 the immediate context of deduction. For instance, tf_partial
10358 could be set here as we might be at the beginning of template
10359 argument deduction when any explicitly specified template
10360 arguments are substituted into the function type. tf_partial
10361 could lead into trouble because we wouldn't find the partial
10362 instantiation that might have been created outside tf_partial
10363 context, because the levels of template parameters wouldn't
10364 match, because in a tf_partial context, tsubst doesn't reduce
10365 TEMPLATE_PARM_LEVEL. */
10368 /* FOUND is either a proper class type, or an alias
10369 template specialization. In the later case, it's a
10370 TYPE_DECL, resulting from the substituting of arguments
10371 for parameters in the TYPE_DECL of the alias template
10372 done earlier. So be careful while getting the template
10373 of FOUND. */
10375 ? found
10382 {
10383 /* If this partial instantiation is specialized, we want to
10384 use it for hash table lookup. */
10388 }
10389 }
10391 /* Build template info for the new specialization. */
10401 /* Note this use of the partial instantiation so we can check it
10402 later in maybe_process_partial_specialization. */
10410 /* Now that the type has been registered on the instantiations
10411 list, we set up the enumerators. Because the enumeration
10412 constants may involve the enumeration type itself, we make
10413 sure to register the type first, and then create the
10414 constants. That way, doing tsubst_expr for the enumeration
10415 constants won't result in recursive calls here; we'll find
10416 the instantiation and exit above. */
10420 /* If the type makes use of template parameters, the
10421 code that generates debugging information will crash. */
10424 /* Possibly limit visibility based on template args. */
10431 }
10432 }
10434 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
10436 tree
10438 {
10442 /* The type of the expression is NULL_TREE since the template-id could refer
10443 to an explicit or partial specialization. */
10445 }
10447 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
10449 tree
10451 {
10463 {
10465 {
10466 auto_diagnostic_group d;
10469 }
10471 }
10474 }
10476 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
10477 TARGS template args, and instantiate it if it's not dependent. */
10479 tree
10481 tsubst_flags_t complain)
10482 {
10485 {
10488 }
10491 }
10493 /* If the set of template parameters PARMS contains a template parameter
10494 at the given LEVEL and INDEX, then return this parameter. Otherwise
10495 return NULL_TREE. */
10497 static tree
10499 {
10508 /* As in template_parm_to_arg. */
10511 else
10516 }
10518 /* Return the template parameter from PARMS that positionally corresponds
10519 to the template parameter PARM, or else return NULL_TREE. */
10521 static tree
10523 {
10527 }
10529 \f
10530 struct pair_fn_data
10531 {
10532 tree_fn_t fn;
10533 tree_fn_t any_fn;
10535 /* True when we should also visit template parameters that occur in
10536 non-deduced contexts. */
10539 };
10541 /* Called from for_each_template_parm via walk_tree. */
10543 static tree
10545 {
10552 #define WALK_SUBTREE(NODE) \
10553 do \
10554 { \
10555 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
10556 pfd->include_nondeduced_p, \
10557 pfd->any_fn); \
10558 if (result) goto out; \
10559 } \
10560 while (0)
10570 {
10574 /* Fall through. */
10580 else
10590 /* Since we're not going to walk subtrees, we have to do this
10591 explicitly here. */
10593 /* Fall through. */
10596 /* Check the return type. */
10599 /* Check the parameter types. Since default arguments are not
10600 instantiated until they are needed, the TYPE_ARG_TYPES may
10601 contain expressions that involve template parameters. But,
10602 no-one should be looking at them yet. And, once they're
10603 instantiated, they don't contain template parameters, so
10604 there's no point in looking at them then, either. */
10605 {
10606 tree parm;
10611 /* Since we've already handled the TYPE_ARG_TYPES, we don't
10612 want walk_tree walking into them itself. */
10614 }
10617 {
10621 }
10655 /* Record template parameters such as `T' inside `TT<T>'. */
10657 /* Fall through. */
10669 /* A template template parameter is encountered. */
10673 /* Already substituted template template parameter */
10678 /* A template-id in a TYPENAME_TYPE might be a deduced context after
10679 partial instantiation. */
10686 /* If there's no type, then this thing must be some expression
10687 involving template parameters. */
10697 /* These are non-deduced contexts. */
10718 {
10722 /* Recursively walk the type of each constraint variable. */
10725 {
10728 }
10729 }
10734 }
10736 #undef WALK_SUBTREE
10738 /* We didn't find any template parameters we liked. */
10739 out:
10741 }
10743 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
10744 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
10745 call FN with the parameter and the DATA.
10746 If FN returns nonzero, the iteration is terminated, and
10747 for_each_template_parm returns 1. Otherwise, the iteration
10748 continues. If FN never returns a nonzero value, the value
10749 returned by for_each_template_parm is 0. If FN is NULL, it is
10750 considered to be the function which always returns 1.
10752 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
10753 parameters that occur in non-deduced contexts. When false, only
10754 visits those template parameters that can be deduced. */
10756 static tree
10760 tree_fn_t any_fn)
10761 {
10763 tree result;
10765 /* Set up. */
10771 /* Walk the tree. (Conceptually, we would like to walk without
10772 duplicates, but for_each_template_parm_r recursively calls
10773 for_each_template_parm, so we would need to reorganize a fair
10774 bit to use walk_tree_without_duplicates, so we keep our own
10775 visited list.) */
10778 else
10781 for_each_template_parm_r,
10785 /* Clean up. */
10787 {
10790 }
10793 }
10795 struct find_template_parameter_info
10796 {
10801 {}
10805 tree parm_list;
10806 tree ctx_parms;
10808 };
10810 /* Appends the declaration of T to the list in DATA. */
10812 static int
10814 {
10817 /* Template parameters declared within the expression are not part of
10818 the parameter mapping. For example, in this concept:
10820 template<typename T>
10821 concept C = requires { <expr> } -> same_as<int>;
10823 the return specifier same_as<int> declares a new decltype parameter
10824 that must not be part of the parameter mapping. The same is true
10825 for generic lambda parameters, lambda template parameters, etc. */
10833 /* We want the underlying TEMPLATE_TEMPLATE_PARM, not the
10834 BOUND_TEMPLATE_TEMPLATE_PARM itself. */
10837 /* This template parameter might be an argument to a cached dependent
10838 specalization that was formed earlier inside some other template, in
10839 which case the parameter is not among the ones that are in-scope.
10840 Look in CTX_PARMS to find the corresponding in-scope template
10841 parameter, and use it instead. */
10845 /* Arguments like const T yield parameters like const T. This means that
10846 a template-id like X<T, const T> would yield two distinct parameters:
10847 T and const T. Adjust types to their unqualified versions. */
10853 /* Verify the parameter we found has a valid index. */
10855 {
10861 }
10864 }
10866 /* Ensure that we recursively examine certain terms that are not normally
10867 visited in for_each_template_parm_r. */
10869 static int
10871 {
10874 #define WALK_SUBTREE(NODE) \
10875 do \
10876 { \
10877 for_each_template_parm (NODE, keep_template_parm, data, \
10878 &ftpi->visited, true, \
10879 any_template_parm_r); \
10880 } \
10881 while (0)
10883 /* A mention of a member alias/typedef is a use of all of its template
10884 arguments, including those from the enclosing class, so we don't use
10885 alias_template_specialization_p here. */
10891 {
10893 /* Type constraints of a placeholder type may contain parameters. */
10900 /* Search through references to variable templates. */
10910 /* If T is a member template that shares template parameters with
10911 ctx_parms, we need to mark all those parameters for mapping.
10912 To that end, it should suffice to just walk the DECL_CONTEXT of
10913 the template (assuming the template is not overly general). */
10918 {
10919 /* Look in the parms and body. */
10923 }
10928 /* The conversion-type-id of a conversion operator may be dependent. */
10939 }
10941 /* Keep walking. */
10943 }
10945 /* Returns a list of unique template parameters found within T, where CTX_PARMS
10946 are the template parameters in scope. */
10948 tree
10950 {
10958 }
10960 /* Returns true if T depends on any template parameter. */
10962 bool
10964 {
10968 /* Namespaces can't depend on any template parameters. */
10984 else
10986 }
10988 /* Returns true iff we're processing an incompletely instantiated function
10989 template. Useful instead of processing_template_decl because the latter
10990 is set to 0 during instantiate_non_dependent_expr. */
10992 bool
10994 {
10995 /* Inspect the less volatile cfun->decl instead of current_function_decl;
10996 the latter might get set for e.g. access checking during satisfaction. */
11005 }
11007 /* Returns true if T depends on any template parameter with level LEVEL. */
11009 bool
11011 {
11014 }
11016 /* Returns true if the signature of DECL depends on any template parameter from
11017 its enclosing class. */
11019 static bool
11021 {
11030 {
11033 {
11038 template_parm_outer_level,
11048 }
11049 }
11053 }
11055 /* Returns true if the constraints of DECL depend on any template parameters
11056 from its enclosing scope. */
11058 bool
11060 {
11071 }
11073 /* Returns TRUE iff INST is an instantiation we don't need to do in an
11074 ill-formed translation unit, i.e. a variable or function that isn't
11075 usable in a constant expression. */
11079 {
11085 }
11087 /* Returns TRUE iff we should refuse to instantiate DECL because it's
11088 neglectable and instantiated from within an erroneous instantiation. */
11090 static bool
11092 {
11098 /* Avoid instantiating members of an ill-formed class. */
11099 bool refuse
11104 {
11109 }
11112 {
11113 /* Don't warn about it not being defined. */
11115 tree clone;
11118 }
11120 }
11128 /* We're starting to instantiate D; record the template instantiation context
11129 at LOC for diagnostics and to restore it later. */
11131 bool
11133 {
11137 {
11138 /* Tell error.cc not to try to instantiate any templates. */
11141 "template instantiation depth exceeds maximum of %d"
11143 max_tinst_depth);
11145 }
11147 /* If the current instantiation caused problems, don't let it instantiate
11148 anything else. Do allow deduction substitution and decls usable in
11149 constant expressions. */
11151 {
11152 /* Avoid no_linkage_errors and unused function (and all other)
11153 warnings for this decl. */
11156 }
11158 /* When not -quiet, dump template instantiations other than functions, since
11159 announce_function will take care of those. */
11181 }
11183 /* We're starting substitution of TMPL<ARGS>; record the template
11184 substitution context for diagnostics and to restore it later. */
11186 bool
11188 {
11190 }
11192 /* We're starting to instantiate D; record INPUT_LOCATION and the
11193 template instantiation context for diagnostics and to restore it
11194 later. */
11196 bool
11198 {
11200 }
11202 /* Likewise, but record LOC as the program location. */
11204 bool
11206 {
11209 }
11211 /* We're done instantiating this template; return to the instantiation
11212 context. */
11214 void
11216 {
11217 /* Restore the filename and line number stashed away when we started
11218 this instantiation. */
11222 }
11224 /* We're instantiating a deferred template; restore the template
11225 instantiation context in which the instantiation was requested, which
11226 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
11228 static tree
11230 {
11242 }
11244 /* Returns the TINST_LEVEL which gives the original instantiation
11245 context. */
11249 {
11255 }
11257 /* True iff T is a friend function declaration that is not itself a template
11258 and is not defined in a class template. */
11260 bool
11262 {
11265 {
11269 /* DECL_FRIEND_CONTEXT is set for a friend defined in class. */
11272 /* Non-templated friends in a class template are still represented with a
11273 TEMPLATE_DECL; check that its primary template is the befriending
11274 class. Note that DECL_PRIMARY_TEMPLATE is null for
11275 template <class T> friend A<T>::f(); */
11279 }
11280 else
11282 }
11284 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
11285 vector of template arguments, as for tsubst.
11287 Returns an appropriate tsubst'd friend declaration. */
11289 static tree
11291 {
11292 tree new_friend;
11297 /* This was a friend declared with an explicit template
11298 argument list, e.g.:
11300 friend void f<>(T);
11302 to indicate that f was a template instantiation, not a new
11303 function declaration. Now, we have to figure out what
11304 instantiation of what template. */
11305 {
11307 tree new_args;
11308 tree tmpl;
11311 /* Friend functions are looked up in the containing namespace scope.
11312 We must enter that scope, to avoid finding member functions of the
11313 current class with same name. */
11328 tsk_none);
11330 }
11336 /* The NEW_FRIEND will look like an instantiation, to the
11337 compiler, but is not an instantiation from the point of view of
11338 the language. For example, we might have had:
11340 template <class T> struct S {
11341 template <class U> friend void f(T, U);
11342 };
11344 Then, in S<int>, template <class U> void f(int, U) is not an
11345 instantiation of anything. */
11349 {
11355 /* Substitute TEMPLATE_PARMS_CONSTRAINTS so that parameter levels will
11356 match in decls_match. */
11361 {
11363 /* As well as each TEMPLATE_PARM_CONSTRAINTS. */
11365 tf_warning_or_error);
11366 }
11367 }
11369 /* The mangled name for the NEW_FRIEND is incorrect. The function
11370 is not a template instantiation and should not be mangled like
11371 one. Therefore, we forget the mangling here; we'll recompute it
11372 later if we need it. */
11374 {
11377 }
11380 {
11381 tree old_decl;
11382 tree ns;
11384 /* We must save some information from NEW_FRIEND before calling
11385 duplicate decls since that function will free NEW_FRIEND if
11386 possible. */
11390 (new_friend_template_info
11397 {
11398 /* This declaration is a `primary' template. */
11403 }
11405 /* Inside pushdecl_namespace_level, we will push into the
11406 current namespace. However, the friend function should go
11407 into the namespace of the template. */
11417 {
11418 /* This new friend declaration matched an existing
11419 declaration. For example, given:
11421 template <class T> void f(T);
11422 template <class U> class C {
11423 template <class T> friend void f(T) {}
11424 };
11426 the friend declaration actually provides the definition
11427 of `f', once C has been instantiated for some type. So,
11428 old_decl will be the out-of-class template declaration,
11429 while new_friend is the in-class definition.
11431 But, if `f' was called before this point, the
11432 instantiation of `f' will have DECL_TI_ARGS corresponding
11433 to `T' but not to `U', references to which might appear
11434 in the definition of `f'. Previously, the most general
11435 template for an instantiation of `f' was the out-of-class
11436 version; now it is the in-class version. Therefore, we
11437 run through all specialization of `f', adding to their
11438 DECL_TI_ARGS appropriately. In particular, they need a
11439 new set of outer arguments, corresponding to the
11440 arguments for this class instantiation.
11442 The same situation can arise with something like this:
11444 friend void f(int);
11445 template <class T> class C {
11446 friend void f(T) {}
11447 };
11449 when `C<int>' is instantiated. Now, `f(int)' is defined
11450 in the class. */
11453 /* On the other hand, if the in-class declaration does
11454 *not* provide a definition, then we don't want to alter
11455 existing definitions. We can just leave everything
11456 alone. */
11457 ;
11458 else
11459 {
11463 /* Overwrite whatever template info was there before, if
11464 any, with the new template information pertaining to
11465 the declaration. */
11469 {
11470 /* We should have called reregister_specialization in
11471 duplicate_decls. */
11476 /* Instantiate it if the global has already been used. */
11480 }
11481 else
11482 {
11483 tree t;
11485 /* Indicate that the old function template is a partial
11486 instantiation. */
11494 /* Reassign any specializations already in the hash table
11495 to the new more general template, and add the
11496 additional template args. */
11500 {
11502 spec_entry elt;
11514 register_specialization
11517 }
11519 }
11520 }
11522 /* The information from NEW_FRIEND has been merged into OLD_DECL
11523 by duplicate_decls. */
11525 }
11526 }
11527 else
11528 {
11532 /* In the code
11533 template <class T> class C {
11534 template <class U> friend void C1<U>::f (); // case 1
11535 friend void C2<T>::f (); // case 2
11536 };
11537 we only need to make sure CONTEXT is a complete type for
11538 case 2. To distinguish between the two cases, we note that
11539 CONTEXT of case 1 remains dependent type after tsubst while
11540 this isn't true for case 2. */
11550 {
11552 /* do_friend adds the TEMPLATE_DECL for any member friend
11553 template even if it isn't a member template, i.e.
11554 template <class T> friend A<T>::f();
11555 Look through it in that case. */
11559 /* Check to see that the declaration is really present, and,
11560 possibly obtain an improved declaration. */
11565 }
11566 }
11569 }
11571 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
11572 template arguments, as for tsubst.
11574 Returns an appropriate tsubst'd friend type or error_mark_node on
11575 failure. */
11577 static tree
11579 {
11580 tree tmpl;
11583 {
11586 }
11591 else
11592 {
11595 }
11601 {
11602 /* The friend template has already been declared. Just
11603 check to see that the declarations match, and install any new
11604 default parameters. We must tsubst the default parameters,
11605 of course. We only need the innermost template parameters
11606 because that is all that redeclare_class_template will look
11607 at. */
11610 {
11614 tf_warning_or_error);
11620 }
11621 }
11622 else
11623 {
11624 /* The friend template has not already been declared. In this
11625 case, the instantiation of the template class will cause the
11626 injection of this template into the namespace scope. */
11630 {
11631 /* The new TMPL is not an instantiation of anything, so we
11632 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
11633 for the new type because that is supposed to be the
11634 corresponding template decl, i.e., TMPL. */
11641 /* Substitute into and set the constraints on the new declaration. */
11643 {
11651 }
11653 /* Inject this template into the enclosing namspace scope. */
11655 }
11656 }
11660 else
11664 }
11666 /* Returns zero if TYPE cannot be completed later due to circularity.
11667 Otherwise returns one. */
11669 static int
11671 {
11681 else
11683 }
11688 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
11689 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
11691 static tree
11694 {
11703 {
11710 clauses
11714 else
11716 }
11720 {
11722 tree varid
11733 {
11737 {
11739 {
11747 }
11748 else
11749 {
11753 {
11754 bool allow_string
11766 {
11767 location_t loc
11769 match_loc);
11775 "integer expression or string "
11777 else
11781 }
11784 {
11785 location_t loc
11787 match_loc);
11791 }
11793 }
11794 }
11795 }
11796 }
11798 }
11799 /* If the first attribute argument is an identifier, don't
11800 pass it through tsubst. Attributes like mode, format,
11801 cleanup and several target specific attributes expect it
11802 unmodified. */
11804 {
11805 tree chain
11810 }
11812 {
11813 /* An attribute pack expansion. */
11822 {
11826 }
11828 }
11829 else
11838 }
11840 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
11841 unchanged or a new TREE_LIST chain. */
11843 static tree
11846 {
11851 {
11855 }
11859 {
11862 {
11865 {
11871 }
11872 }
11874 }
11877 }
11879 /* Apply any attributes which had to be deferred until instantiation
11880 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
11881 ARGS, COMPLAIN, IN_DECL are as tsubst. Returns true normally,
11882 false on error. */
11884 static bool
11887 {
11888 tree t;
11895 {
11899 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
11900 to our attributes parameter. */
11902 }
11903 else
11904 {
11906 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
11907 lookup_template_class_1, and should be preserved. */
11911 }
11913 /* save_template_attributes puts the dependent attributes at the beginning of
11914 the list; find the non-dependent ones. */
11920 /* Apply any non-dependent attributes. */
11926 /* And then any dependent ones. */
11930 {
11935 {
11938 }
11941 }
11943 /* cplus_decl_attributes can add some attributes implicitly. For templates,
11944 those attributes should have been added already when those templates were
11945 parsed, and shouldn't be added based on from which context they are
11946 first time instantiated. */
11949 optimization_default_node);
11952 NULL);
11957 }
11959 /* The template TMPL is being instantiated with the template arguments TARGS.
11960 Perform the access checks that we deferred when parsing the template. */
11962 static void
11964 {
11974 {
11982 /* Make access check error messages point to the location
11983 of the use of the typedef. */
11987 }
11988 }
11990 tree
11992 {
11996 tree typedecl;
11997 tree pbinfo;
11998 tree base_list;
12000 tree fn_context;
12009 /* Figure out which template is being instantiated. */
12013 /* Mark the type as in the process of being defined. */
12016 /* We may be in the middle of deferred access check. Disable
12017 it now. */
12020 /* Determine what specialization of the original template to
12021 instantiate. */
12026 {
12027 /* This TYPE is actually an instantiation of a partial
12028 specialization. We replace the innermost set of ARGS with
12029 the arguments appropriate for substitution. For example,
12030 given:
12032 template <class T> struct S {};
12033 template <class T> struct S<T*> {};
12035 and supposing that we are instantiating S<int*>, ARGS will
12036 presently be {int*} -- but we need {int}. */
12039 }
12040 else
12041 {
12044 }
12046 /* If the template we're instantiating is incomplete, then clearly
12047 there's nothing we can do. */
12049 {
12050 /* We can try again later. */
12053 }
12055 /* If we've recursively instantiated too many templates, stop. */
12063 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
12068 else
12069 {
12072 }
12073 /* Use #pragma pack from the template context. */
12079 /* Set the input location to the most specialized template definition.
12080 This is needed if tsubsting causes an error. */
12094 {
12097 /* Adjust visibility for template arguments. */
12099 }
12105 /* We should never instantiate a nested class before its enclosing
12106 class; we need to look up the nested class by name before we can
12107 instantiate it, and that lookup should instantiate the enclosing
12108 class. */
12113 /* Defer access checking while we substitute into the types named in
12114 the base-clause. */
12117 {
12118 tree pbase_binfo;
12121 /* Substitute into each of the bases to determine the actual
12122 basetypes. */
12124 {
12125 tree base;
12131 {
12132 expanded_bases =
12139 }
12142 {
12144 /* Extract the already-expanded base class. */
12146 else
12147 /* Substitute to figure out the base class. */
12149 NULL_TREE);
12157 }
12158 }
12160 /* The list is now in reverse order; correct that. */
12162 }
12163 /* Now call xref_basetypes to set up all the base-class
12164 information. */
12172 /* Now that our base classes are set up, enter the scope of the
12173 class, so that name lookups into base classes, etc. will work
12174 correctly. This is precisely analogous to what we do in
12175 begin_class_definition when defining an ordinary non-template
12176 class, except we also need to push the enclosing classes. */
12179 /* Now check accessibility of the types named in its base-clause,
12180 relative to the scope of the class. */
12183 /* A vector to hold members marked with attribute used. */
12186 /* Now members are processed in the order of declaration. */
12189 {
12193 {
12195 {
12197 /* A closure type for a lambda in an NSDMI or default argument.
12198 Ignore it; it will be regenerated when needed. */
12205 /* If the member is a class template, then -- even after
12206 substitution -- there may be dependent types in the
12207 template argument list for the class. We increment
12208 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
12209 that function will assume that no types are dependent
12210 when outside of a template. */
12220 {
12224 /* Unfortunately, lookup_template_class sets
12225 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
12226 instantiation (i.e., for the type of a member
12227 template class nested within a template class.)
12228 This behavior is required for
12229 maybe_process_partial_specialization to work
12230 correctly, but is not accurate in this case;
12231 the TAG is not an instantiation of anything.
12232 (The corresponding TEMPLATE_DECL is an
12233 instantiation, but the TYPE is not.) */
12236 /* Now, install the tag. We don't use pushtag
12237 because that does too much work -- creating an
12238 implicit typedef, which we've already done. */
12243 }
12244 }
12246 {
12247 tree r;
12256 /* Instantiate members marked with attribute used. */
12262 }
12265 /* A closure type for a lambda in an NSDMI or default argument.
12267 else
12268 {
12269 /* Build new TYPE_FIELDS. */
12274 {
12275 tree r;
12280 /* The file and line for this declaration, to
12281 assist in error message reporting. Since we
12282 called push_tinst_level above, we don't need to
12283 restore these. */
12293 {
12294 /* A capture pack became multiple fields. */
12297 }
12300 {
12304 {
12305 /* In [temp.inst]:
12307 [t]he initialization (and any associated
12308 side-effects) of a static data member does
12309 not occur unless the static data member is
12310 itself used in a way that requires the
12311 definition of the static data member to
12312 exist.
12314 Therefore, we do not substitute into the
12315 initialized for the static data member here. */
12316 finish_static_data_member_decl
12322 /* Instantiate members marked with attribute used. */
12325 }
12327 {
12328 /* Determine whether R has a valid type and can be
12329 completed later. If R is invalid, then its type
12330 is replaced by error_mark_node. */
12336 {
12337 /* If R's type couldn't be completed and
12338 it isn't a flexible array member (whose
12339 type is incomplete by definition) give
12340 an error. */
12343 }
12348 {
12351 }
12355 }
12357 /* If it is a TYPE_DECL for a class-scoped
12358 ENUMERAL_TYPE, such a thing will already have
12359 been added to the field list by tsubst_enum
12360 in finish_member_declaration case above. */
12364 {
12367 }
12368 }
12369 }
12370 }
12371 }
12372 else
12373 {
12376 {
12377 /* Build new CLASSTYPE_FRIEND_CLASSES. */
12381 {
12382 /* template <class T> friend class C; */
12384 }
12386 {
12387 /* template <class T> friend class C::D; */
12392 }
12395 {
12396 /* This could be either
12398 friend class T::C;
12400 when dependent_type_p is false or
12402 template <class U> friend class T::C;
12404 otherwise. */
12405 /* Bump processing_template_decl in case this is something like
12406 template <class T> friend struct A<T>::B. */
12411 }
12413 /* friend class C<T>; */
12417 /* Otherwise it's
12419 friend class C;
12421 where C is already declared or
12423 friend class C<int>;
12425 We don't have to do anything in these cases. */
12429 }
12430 else
12431 {
12432 /* Build new DECL_FRIENDLIST. */
12433 tree r;
12435 /* The file and line for this declaration, to
12436 assist in error message reporting. Since we
12437 called push_tinst_level above, we don't need to
12438 restore these. */
12442 {
12445 }
12450 {
12453 }
12454 }
12455 }
12456 }
12459 {
12460 /* Restore these before substituting into the lambda capture
12461 initializers. */
12464 }
12466 /* Set the file and line number information to whatever is given for
12467 the class itself. This puts error messages involving generated
12468 implicit functions at a predictable point, and the same point
12469 that would be used for non-template classes. */
12476 /* Remember if instantiating this class ran into errors, so we can avoid
12477 instantiating member functions in limit_bad_template_recursion. We set
12478 this flag even if the problem was in another instantiation triggered by
12479 this one, as that will likely also cause trouble for member functions. */
12483 /* We don't instantiate default arguments for member functions. 14.7.1:
12485 The implicit instantiation of a class template specialization causes
12486 the implicit instantiation of the declarations, but not of the
12487 definitions or default arguments, of the class member functions,
12488 member classes, static data members and member templates.... */
12493 /* Now that we've gone through all the members, instantiate those
12494 marked with attribute used. We must do this in the context of
12495 the class -- not the context we pushed from, as that might be
12496 inside a template and change the behaviour of mark_used. */
12506 /* The vtable for a template class can be emitted in any translation
12507 unit in which the class is instantiated. When there is no key
12508 method, however, finish_struct_1 will already have added TYPE to
12509 the keyed_classes. */
12514 }
12516 tree
12518 {
12519 tree r;
12525 else
12526 {
12533 }
12536 }
12538 /* Given a function parameter pack TMPL_PARM and some function parameters
12539 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
12540 and set *SPEC_P to point at the next point in the list. */
12542 tree
12544 {
12545 /* Collect all of the extra "packed" parameters into an
12546 argument pack. */
12547 tree argpack;
12558 {
12559 /* The instantiation is still a parameter pack; don't wrap it in a
12560 NONTYPE_ARGUMENT_PACK. */
12563 }
12564 else
12565 {
12566 /* Fill in PARMVEC with all of the parameters. */
12570 {
12576 }
12578 /* Build the argument packs. */
12580 }
12584 }
12586 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
12587 NONTYPE_ARGUMENT_PACK. */
12589 static tree
12591 {
12593 }
12595 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
12596 pack expansion with no extra args, 2 if it has extra args, or 0
12597 if it is not a pack expansion. */
12599 static int
12601 {
12603 /* We're being called before this happens in tsubst_pack_expansion. */
12610 /* A decl pack is itself an expansion. */
12617 }
12620 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
12622 static tree
12624 {
12631 }
12633 /* This is a subroutine of tsubst_pack_expansion.
12635 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
12636 mechanism to store the (non complete list of) arguments of the
12637 substitution and return a non substituted pack expansion, in order
12638 to wait for when we have enough arguments to really perform the
12639 substitution. */
12641 static bool
12643 tree parm_packs,
12646 {
12651 /* If one pack has an expansion and another pack has a normal
12652 argument or if one pack has an empty argument and an another
12653 one hasn't then tsubst_pack_expansion cannot perform the
12654 substitution and need to fall back on the
12655 PACK_EXPANSION_EXTRA mechanism. */
12659 {
12660 /* If all the actual packs are pack expansions, we can still
12661 subsitute directly. */
12663 {
12673 }
12675 }
12678 {
12682 parm_pack;
12684 {
12689 /* We can't substitute a pack expansion with extra args into
12690 our pattern. */
12694 else
12696 }
12699 {
12702 }
12703 }
12705 }
12707 /* [temp.variadic]/6 says that:
12709 The instantiation of a pack expansion [...]
12710 produces a list E1,E2, ..., En, where N is the number of elements
12711 in the pack expansion parameters.
12713 This subroutine of tsubst_pack_expansion produces one of these Ei.
12715 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
12716 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
12717 PATTERN, and each TREE_VALUE is its corresponding argument pack.
12718 INDEX is the index 'i' of the element Ei to produce. ARGS,
12719 COMPLAIN, and IN_DECL are the same parameters as for the
12720 tsubst_pack_expansion function.
12722 The function returns the resulting Ei upon successful completion,
12723 or error_mark_node.
12725 Note that this function possibly modifies the ARGS parameter, so
12726 it's the responsibility of the caller to restore it. */
12728 static tree
12730 tree parm_packs,
12732 tree args /* This parm gets
12734 tsubst_flags_t complain,
12735 tree in_decl)
12736 {
12737 tree t;
12740 /* For each parameter pack, change the substitution of the parameter
12741 pack to the ith argument in its argument pack, then expand the
12742 pattern. */
12744 {
12749 ith_elem_is_expansion |=
12752 /* Select the Ith argument from the pack. */
12756 {
12758 {
12763 }
12764 else
12766 }
12767 else
12768 {
12773 {
12775 /* Update the corresponding argument. */
12777 }
12778 else
12779 /* Re-use the ARGUMENT_PACK_SELECT. */
12781 }
12783 }
12785 /* Substitute into the PATTERN with the (possibly altered)
12786 arguments. */
12788 /* Expanding a fixed parameter pack from
12789 coerce_template_parameter_pack. */
12796 else
12797 {
12800 /* When expanding the fake auto... pack expansion from add_capture, we
12801 need to mark that the expansion is no longer a pack. */
12803 }
12805 /* If the Ith argument pack element is a pack expansion, then
12806 the Ith element resulting from the substituting is going to
12807 be a pack expansion as well. */
12812 }
12814 /* When the unexpanded parameter pack in a fold expression expands to an empty
12815 sequence, the value of the expression is as follows; the program is
12816 ill-formed if the operator is not listed in this table.
12818 && true
12819 || false
12820 , void() */
12822 tree
12824 {
12828 {
12837 }
12843 }
12845 /* Given a fold-expression T and a current LEFT and RIGHT operand,
12846 form an expression that combines the two terms using the
12847 operator of T. */
12849 static tree
12851 {
12856 // Handle compound assignment operators.
12863 {
12872 complain);
12873 }
12874 }
12876 /* Substitute ARGS into the pack of a fold expression T. */
12880 {
12882 }
12884 /* Substitute ARGS into the pack of a fold expression T. */
12888 {
12890 }
12892 /* Expand a PACK of arguments into a grouped as left fold.
12893 Given a pack containing elements A0, A1, ..., An and an
12894 operator @, this builds the expression:
12896 ((A0 @ A1) @ A2) ... @ An
12898 Note that PACK must not be empty.
12900 The operator is defined by the original fold expression T. */
12902 static tree
12904 {
12907 {
12910 }
12912 }
12914 /* Substitute into a unary left fold expression. */
12916 static tree
12918 tree in_decl)
12919 {
12924 {
12928 }
12931 else
12933 }
12935 /* Substitute into a binary left fold expression.
12937 Do ths by building a single (non-empty) vector of argumnts and
12938 building the expression from those elements. */
12940 static tree
12942 tree in_decl)
12943 {
12952 {
12957 }
12965 }
12967 /* Expand a PACK of arguments into a grouped as right fold.
12968 Given a pack containing elementns A0, A1, ..., and an
12969 operator @, this builds the expression:
12971 A0@ ... (An-2 @ (An-1 @ An))
12973 Note that PACK must not be empty.
12975 The operator is defined by the original fold expression T. */
12977 tree
12979 {
12980 // Build the expression.
12984 {
12987 }
12989 }
12991 /* Substitute into a unary right fold expression. */
12993 static tree
12995 tree in_decl)
12996 {
13001 {
13005 }
13008 else
13010 }
13012 /* Substitute into a binary right fold expression.
13014 Do ths by building a single (non-empty) vector of arguments and
13015 building the expression from those elements. */
13017 static tree
13019 tree in_decl)
13020 {
13029 {
13034 }
13043 }
13045 /* Walk through the pattern of a pack expansion, adding everything in
13046 local_specializations to a list. */
13048 class el_data
13049 {
13051 /* Set of variables declared within the pattern. */
13053 /* Set of AST nodes that have been visited by the traversal. */
13055 /* List of local_specializations used within the pattern. */
13056 tree extra;
13057 tsubst_flags_t complain;
13061 };
13062 static tree
13064 {
13070 /* Remember local typedefs (85214). */
13074 {
13080 {
13083 decl2
13089 {
13092 }
13093 }
13094 }
13096 {
13097 /* Since we defer implicit capture, look in the parms and body. */
13103 }
13105 {
13107 /* Don't mess with variables declared within the pattern. */
13110 {
13111 /* Maybe pull out the PARM_DECL for a partial instantiation. */
13114 {
13120 }
13122 {
13123 /* Handle lambda capture here, since we aren't doing any
13124 substitution now, and so tsubst_copy won't call
13125 process_outer_var_ref. */
13129 {
13135 {
13136 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
13137 proxies. */
13139 {
13144 }
13146 }
13147 }
13148 }
13149 }
13153 }
13155 }
13156 static tree
13158 {
13162 }
13164 /* Extract any uses of local_specializations from PATTERN and add them to ARGS
13165 for use in PACK_EXPANSION_EXTRA_ARGS. */
13167 tree
13169 {
13170 /* Make a copy of the extra arguments so that they won't get changed
13171 out from under us. */
13177 }
13179 /* Apply any local specializations from PACK_EXPANSION_EXTRA_ARGS and add the
13180 normal template args to ARGS. */
13182 tree
13184 {
13186 {
13188 {
13189 /* The partial instantiation involved local declarations collected in
13190 extract_local_specs; map from the general template to our local
13191 context. */
13197 /* else inst is already a full instantiation of the pack. */
13199 }
13202 }
13204 {
13205 /* This can happen after dependent substitution into a
13206 requires-expr or a lambda that uses constexpr if. */
13209 }
13210 else
13213 }
13215 /* Substitute ARGS into T, which is an pack expansion
13216 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
13217 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
13218 (if only a partial substitution could be performed) or
13219 ERROR_MARK_NODE if there was an error. */
13220 tree
13222 tree in_decl)
13223 {
13224 tree pattern;
13228 tree result;
13235 /* Add in any args remembered from an earlier partial instantiation. */
13240 /* Determine the argument packs that will instantiate the parameter
13241 packs used in the expansion expression. While we're at it,
13242 compute the number of arguments to be expanded and make sure it
13243 is consistent. */
13246 {
13253 {
13259 complain);
13260 else
13264 }
13266 {
13268 {
13271 parm_pack);
13273 }
13276 }
13278 {
13279 /* We know we have correct local_specializations if this
13280 expansion is at function scope, or if we're dealing with a
13281 local parameter in a requires expression; for the latter,
13282 tsubst_requires_expr set it up appropriately. */
13285 else
13286 /* We can't rely on local_specializations for a parameter
13287 name used later in a function declaration (such as in a
13288 late-specified return type). Even if it exists, it might
13289 have the wrong value for a recursive call. */
13293 {
13294 /* This parameter pack was used in an unevaluated context. Just
13295 make a dummy decl, since it's only used for its type. */
13300 /* Partial instantiation of the parm_pack, we can't build
13301 up an argument pack yet. */
13303 else
13305 }
13307 /* This argument pack isn't fully instantiated yet. */
13309 }
13311 {
13315 }
13316 else
13317 {
13326 }
13333 /* This can only happen if we forget to expand an argument
13334 pack somewhere else. Just return an error, silently. */
13335 {
13339 }
13342 {
13346 /* Don't bother trying to do a partial substitution with
13347 incomplete packs; we'll try again after deduction. */
13354 {
13359 pattern);
13360 else
13362 pattern);
13364 }
13366 /* Keep track of the parameter packs and their corresponding
13367 argument packs. */
13370 }
13371 else
13372 {
13373 /* We can't substitute for this parameter pack. We use a flag as
13374 well as the missing_level counter because function parameter
13375 packs don't have a level. */
13378 }
13379 }
13381 /* If the expansion is just T..., return the matching argument pack, unless
13382 we need to call convert_from_reference on all the elements. This is an
13383 important optimization; see c++/68422. */
13386 {
13389 /* If the argument pack is a single pack expansion, pull it out. */
13394 /* Types need no adjustment, nor does sizeof..., and if we still have
13395 some pack expansion args we won't do anything yet. */
13400 /* Also optimize expression pack expansions if we can tell that the
13401 elements won't have reference type. */
13407 /* Otherwise use the normal path so we get convert_from_reference. */
13408 }
13410 /* We cannot expand this expansion expression, because we don't have
13411 all of the argument packs we need. */
13413 {
13414 /* We got some full packs, but we can't substitute them in until we
13415 have values for all the packs. So remember these until then. */
13421 }
13423 /* If NEED_LOCAL_SPECIALIZATIONS then we're in a late-specified return
13424 type, so create our own local specializations map; the current map is
13425 either NULL or (in the case of recursive unification) might have
13426 bindings that we don't want to use or alter. */
13431 {
13432 /* There were no real arguments, we're just replacing a parameter
13433 pack with another version of itself. Substitute into the
13434 pattern and return a PACK_EXPANSION_*. The caller will need to
13435 deal with that. */
13439 else
13445 {
13446 /* This is a fake auto... pack expansion created in add_capture with
13447 _PACKS that don't appear in the pattern. Copy one over. */
13454 }
13456 }
13460 /* For each argument in each argument pack, substitute into the
13461 pattern. */
13465 {
13467 i,
13469 in_decl);
13472 {
13475 }
13476 }
13478 /* Update ARGS to restore the substitution from parameter packs to
13479 their argument packs. */
13481 {
13488 else
13489 {
13497 /* Update the corresponding argument. */
13501 else
13503 }
13504 }
13506 /* If the dependent pack arguments were such that we end up with only a
13507 single pack expansion again, there's no need to keep it in a TREE_VEC. */
13513 }
13515 /* Make an argument pack out of the TREE_VEC VEC. */
13517 static tree
13519 {
13520 tree pack;
13524 else
13525 {
13528 }
13531 }
13533 /* Return an exact copy of template args T that can be modified
13534 independently. */
13536 static tree
13538 {
13546 {
13551 }
13557 }
13559 /* Substitute ARGS into the *_ARGUMENT_PACK orig_arg. */
13561 tree
13563 tree in_decl)
13564 {
13565 /* This flag is used only during deduction, and we don't expect to
13566 substitute such ARGUMENT_PACKs. */
13569 /* Substitute into each of the arguments. */
13578 /* If we're substituting into a generic ARGUMENT_PACK for a variadic
13579 template parameter, we might be able to avoid allocating a new
13580 ARGUMENT_PACK and reuse the corresponding ARGUMENT_PACK from ARGS
13581 if the substituted result is identical to it. */
13583 {
13590 {
13593 }
13594 }
13596 tree new_arg;
13598 {
13601 }
13602 else
13603 {
13606 }
13609 }
13611 /* Substitute ARGS into the vector or list of template arguments T. */
13613 tree
13615 {
13623 /* True iff the substituted result is identical to T. */
13627 {
13629 tree new_arg;
13636 {
13637 /* Substitute into an expansion expression. */
13641 /* Add to the expanded length adjustment the number of
13642 expanded arguments. We subtract one from this
13643 measurement, because the argument pack expression
13644 itself is already counted as 1 in
13645 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
13646 the argument pack is empty. */
13648 }
13651 else
13660 }
13667 /* If ARGS and T are both multi-level, the substituted result may be
13668 identical to ARGS. */
13673 /* If T appears to be a vector of generic template arguments, the
13674 substituted result may be identical to the corresponding level
13675 from ARGS. */
13677 {
13682 }
13684 /* If the substituted result is identical to MAYBE_REUSE, return
13685 it and avoid allocating a new TREE_VEC, as an optimization. */
13691 /* If T consists of only a pack expansion for which substitution yielded
13692 a TREE_VEC of the expanded elements, then reuse that TREE_VEC instead
13693 of effectively making a copy. */
13699 /* Make space for the expanded arguments coming from template
13700 argument packs. */
13702 /* T can contain TREE_VECs. That happens if T contains the
13703 arguments for a member template.
13704 In that case each TREE_VEC in T represents a level of template
13705 arguments, and T won't carry any non defaulted argument count.
13706 It will rather be the nested TREE_VECs that will carry one.
13707 In other words, T carries a non defaulted argument count only
13708 if it doesn't contain any nested TREE_VEC. */
13710 {
13714 }
13718 {
13723 {
13724 /* Now expand the template argument pack "in place". */
13727 }
13728 else
13729 {
13731 out++;
13732 }
13733 }
13737 }
13739 /* Substitute ARGS into one level PARMS of template parameters. */
13741 static tree
13743 {
13750 {
13758 }
13761 }
13763 /* Return the result of substituting ARGS into the template parameters
13764 given by PARMS. If there are m levels of ARGS and m + n levels of
13765 PARMS, then the result will contain n levels of PARMS. For
13766 example, if PARMS is `template <class T> template <class U>
13767 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
13768 result will be `template <int*, double, class V>'. */
13770 static tree
13772 {
13776 /* When substituting into a template, we must set
13777 PROCESSING_TEMPLATE_DECL as the template parameters may be
13778 dependent if they are based on one-another, and the dependency
13779 predicates are short-circuit outside of templates. */
13786 {
13795 }
13800 }
13802 /* Return the result of substituting ARGS into one template parameter
13803 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
13804 parameter and which TREE_PURPOSE is the default argument of the
13805 template parameter. */
13807 static tree
13809 {
13832 }
13834 /* Substitute in-place the TEMPLATE_PARM_CONSTRAINTS of each template
13835 parameter in PARMS for sake of declaration matching. */
13837 static void
13839 tsubst_flags_t complain)
13840 {
13843 {
13849 }
13851 }
13853 /* Substitute the ARGS into the indicated aggregate (or enumeration)
13854 type T. If T is not an aggregate or enumeration type, it is
13855 handled as if by tsubst. IN_DECL is as for tsubst. If
13856 ENTERING_SCOPE is nonzero, T is the context for a template which
13857 we are presently tsubst'ing. Return the substituted value. */
13859 static tree
13861 tree args,
13862 tsubst_flags_t complain,
13863 tree in_decl,
13865 {
13869 /* If T is an alias template specialization, we want to substitute that
13870 rather than strip it, especially if it's dependent_alias_template_spec_p.
13871 It should be OK not to handle entering_scope in this case, since
13872 DECL_CONTEXT will never be an alias template specialization. We only get
13873 here with an alias when tsubst calls us for TYPENAME_TYPE. */
13878 {
13883 /* Fall through. */
13887 {
13888 tree argvec;
13889 tree r;
13891 /* In "sizeof(X<I>)" we need to evaluate "I". */
13892 cp_evaluated ev;
13894 /* Figure out what arguments are appropriate for the
13895 type we are trying to find. For example, given:
13897 template <class T> struct S;
13898 template <class T, class U> void f(T, U) { S<U> su; }
13900 and supposing that we are instantiating f<int, double>,
13901 then our ARGS will be {int, double}, but, when looking up
13902 S we only want {double}. */
13907 else
13908 {
13912 }
13915 }
13916 else
13917 /* This is not a template type, so there's nothing to do. */
13922 }
13923 }
13925 /* Map from a FUNCTION_DECL to a vec of default argument instantiations,
13926 indexed in reverse order of the parameters. */
13930 /* Return a reference to the vec* of defarg insts for FN. */
13934 {
13938 tree_vec_map **slot
13941 {
13944 }
13946 }
13948 /* Substitute into the default argument ARG (a default argument for
13949 FN), which has the indicated TYPE. */
13951 tree
13953 tsubst_flags_t complain)
13954 {
13957 /* This can happen in invalid code. */
13961 /* Shortcut {}. */
13976 /* Remember the location of the pointer to the vec rather than the location
13977 of the particular element, in case the vec grows in tsubst_expr. */
13979 /* Index in reverse order to avoid allocating space for initial parameters
13980 that don't have default arguments. */
13987 /* This default argument came from a template. Instantiate the
13988 default argument here, not in tsubst. In the case of
13989 something like:
13991 template <class T>
13992 struct S {
13993 static T t();
13994 void f(T = t());
13995 };
13997 we must be careful to do name lookup in the scope of S<T>,
13998 rather than in the current class. */
14004 /* The default argument expression may cause implicitly defined
14005 member functions to be synthesized, which will result in garbage
14006 collection. We must treat this situation as if we were within
14007 the body of function so as to avoid collecting live data on the
14008 stack. */
14017 /* Make sure the default argument is reasonable. */
14033 }
14035 /* Substitute into all the default arguments for FN. */
14037 static void
14039 {
14040 tree arg;
14041 tree tmpl_args;
14045 /* If this function is not yet instantiated, we certainly don't need
14046 its default arguments. */
14049 /* Don't do this again for clones. */
14055 arg;
14061 complain);
14062 }
14064 /* Hash table mapping a FUNCTION_DECL to its dependent explicit-specifier. */
14067 /* Store a pair to EXPLICIT_SPECIFIER_MAP. */
14069 void
14071 {
14076 }
14078 /* Lookup an element in EXPLICIT_SPECIFIER_MAP. */
14080 tree
14082 {
14084 }
14086 /* Given T, a FUNCTION_TYPE or METHOD_TYPE, construct and return a corresponding
14087 FUNCTION_TYPE or METHOD_TYPE whose return type is RETURN_TYPE, argument types
14088 are ARG_TYPES, and exception specification is RAISES, and otherwise is
14089 identical to T. */
14091 static tree
14094 {
14097 tree new_type;
14099 {
14102 }
14103 else
14104 {
14106 /* Don't pick up extra function qualifiers from the basetype. */
14109 {
14110 /* [temp.deduct]
14112 Type deduction may fail for any of the following
14113 reasons:
14115 -- Attempting to create "pointer to member of T" when T
14116 is not a class type. */
14119 r);
14121 }
14125 }
14131 }
14133 /* Check if the function type of DECL, a FUNCTION_DECL, agrees with the type of
14134 each of its formal parameters. If there is a disagreement then rebuild
14135 DECL's function type according to its formal parameter types, as part of a
14136 resolution for Core issues 1001/1322. */
14138 static void
14140 {
14143 {
14146 {
14150 {
14153 }
14157 }
14158 }
14169 {
14174 }
14176 {
14186 }
14194 }
14196 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
14198 static tree
14200 tree lambda_fntype)
14201 {
14206 /* Nobody should be tsubst'ing into non-template functions. */
14211 {
14214 }
14216 {
14217 /* If T is not dependent, just return it. */
14222 /* A non-templated friend doesn't get DECL_TEMPLATE_INFO. */
14226 /* Calculate the most general template of which R is a
14227 specialization. */
14230 /* We're substituting a lambda function under tsubst_lambda_expr but not
14231 directly from it; find the matching function we're already inside.
14232 But don't do this if T is a generic lambda with a single level of
14233 template parms, as in that case we're doing a normal instantiation. */
14239 /* Calculate the complete set of arguments used to
14240 specialize R. */
14242 (DECL_TEMPLATE_RESULT
14248 /* Check to see if we already have this specialization. */
14250 {
14253 /* The spec for these args might be a partial instantiation of the
14254 template, but here what we want is the FUNCTION_DECL. */
14256 }
14257 }
14258 else
14259 {
14260 /* This special case arises when we have something like this:
14262 template <class T> struct S {
14263 friend void f<int>(int, double);
14264 };
14266 Here, the DECL_TI_TEMPLATE for the friend declaration
14267 will be an IDENTIFIER_NODE. We are being called from
14268 tsubst_friend_function, and we want only to create a
14269 new decl (R) with appropriate types so that we can call
14270 determine_specialization. */
14271 friend_case:
14274 }
14291 /* If we hit excessive deduction depth, the type is bogus even if
14292 it isn't error_mark_node, so don't build a decl. */
14296 /* We do NOT check for matching decls pushed separately at this
14297 point, as they may not represent instantiations of this
14298 template, and in any case are considered separate under the
14299 discrete model. */
14303 /* Clear out the mangled name and RTL for the instantiation. */
14306 /* Leave DECL_INITIAL set on deleted instantiations. */
14312 /* Handle explicit(dependent-expr). */
14314 {
14322 else
14323 {
14326 }
14327 }
14329 /* OpenMP UDRs have the only argument a reference to the declared
14330 type. We want to diagnose if the declared type is a reference,
14331 which is invalid, but as references to references are usually
14332 quietly merged, diagnose it here. */
14334 {
14335 tree argtype
14340 "reference type %qT in "
14344 argtype);
14345 }
14348 /* Type-conversion operator. Reconstruct the name, in
14349 case it's the name of one of the template's parameters. */
14359 {
14364 }
14373 /* If this is an instantiation of a function with internal
14374 linkage, we already know what object file linkage will be
14375 assigned to the instantiation. */
14384 /* We'll re-clone as appropriate in instantiate_template. */
14387 /* If we aren't complaining now, return on error before we register
14388 the specialization so that we'll complain eventually. */
14394 /* Associate the constraints directly with the instantiation. We
14395 don't substitute through the constraints; that's only done when
14396 they are checked. */
14409 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
14410 this in the special friend case mentioned above where
14411 GEN_TMPL is NULL. */
14413 {
14418 tree new_r
14421 /* We instantiated this while substituting into
14422 the type earlier (template/friend54.C). */
14425 /* We're not supposed to instantiate default arguments
14426 until they are called, for a template. But, for a
14427 declaration like:
14429 template <class T> void f ()
14430 { extern void g(int i = T()); }
14432 we should do the substitution when the template is
14433 instantiated. We handle the member function case in
14434 instantiate_class_template since the default arguments
14435 might refer to other members of the class. */
14440 }
14442 {
14445 }
14446 else
14449 /* Copy the list of befriending classes. */
14453 {
14457 }
14460 {
14464 /* If this is an instantiation of a member template, clone it.
14465 If it isn't, that'll be handled by
14466 clone_constructors_and_destructors. */
14469 }
14475 /* Possibly limit visibility based on template args. */
14478 {
14482 }
14494 }
14496 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
14498 static tree
14500 tree lambda_fntype)
14501 {
14502 /* We can get here when processing a member function template,
14503 member class template, or template template parameter. */
14506 tree spec;
14507 tree tmpl_args;
14508 tree full_args;
14509 tree r;
14513 {
14514 /* Template template parameter is treated here. */
14518 /* If we get a real template back, return it. This can happen in
14519 the context of most_specialized_partial_spec. */
14522 else
14523 /* The new TEMPLATE_DECL was built in
14524 reduce_template_parm_level. */
14527 }
14530 {
14531 /* We might already have an instance of this template.
14532 The ARGS are for the surrounding class type, so the
14533 full args contain the tsubst'd args for the context,
14534 plus the innermost args from the template decl. */
14538 /* Because this is a template, the arguments will still be
14539 dependent, even after substitution. If
14540 PROCESSING_TEMPLATE_DECL is not set, the dependency
14541 predicates will short-circuit. */
14549 /* If this is a default template template argument,
14550 tsubst might not have changed anything. */
14557 {
14559 /* Type partial instantiations are stored as the type by
14560 lookup_template_class_1, not here as the template. */
14563 }
14564 }
14566 /* Make a new template decl. It will be similar to the
14567 original, but will record the current template arguments.
14568 We also create a new function declaration, which is just
14569 like the old one, but points to this new template, rather
14570 than the old one. */
14575 // Build new template info linking to the original template decl.
14577 {
14580 }
14581 else
14584 /* The template parameters for this new template are all the
14585 template parameters for the old template, except the
14586 outermost level of parameters. */
14589 = current_template_parms
14591 complain);
14598 else
14599 {
14601 {
14604 }
14608 else
14610 }
14616 {
14617 /* For a partial specialization, we need to keep pointing to
14618 the primary template. */
14624 }
14626 {
14629 }
14630 else
14631 {
14634 }
14641 {
14642 /* Propagate module information from the decl. */
14645 /* If this is a constrained template, the above tsubst of
14646 inner can find the unconstrained template, which may have
14647 come from an import. This is ok, because we don't
14648 register this instantiation (see below). */
14650 || (TEMPLATE_PARMS_CONSTRAINTS
14652 }
14661 /* Record this non-type partial instantiation. */
14667 }
14669 /* True if FN is the op() for a lambda in an uninstantiated template. */
14671 bool
14673 {
14678 }
14680 /* True if FN is the substitution (via tsubst_lambda_expr) of a function for
14681 which the above is true. */
14683 bool
14685 {
14691 }
14693 /* Return the LAMBDA_EXPR from which T was ultimately regenerated.
14694 If T is not a regenerated LAMBDA_EXPR, return T. */
14696 tree
14698 {
14702 }
14704 /* Return the set of template arguments used to regenerate the lambda T
14705 from its most general lambda. */
14707 tree
14709 {
14715 else
14717 }
14719 /* We're instantiating a variable from template function TCTX. Return the
14720 corresponding current enclosing scope. We can match them up using
14721 DECL_SOURCE_LOCATION because lambdas only ever have one source location, and
14722 the DECL_SOURCE_LOCATION for a function instantiation is updated to match
14723 the template definition in regenerate_decl_from_template. */
14725 static tree
14727 {
14730 /* We shouldn't ever need to do this for other artificial functions. */
14737 }
14739 /* Substitute the ARGS into the T, which is a _DECL. Return the
14740 result of the substitution. Issue error and warning messages under
14741 control of COMPLAIN. */
14743 static tree
14745 {
14746 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
14747 location_t saved_loc;
14752 /* Set the filename and linenumber to improve error-reporting. */
14757 {
14767 {
14775 {
14776 /* If there is a local specialization that isn't a
14777 parameter pack, it means that we're doing a "simple"
14778 substitution from inside tsubst_pack_expansion. Just
14779 return the local specialization (which will be a single
14780 parm). */
14787 /* Expand the TYPE_PACK_EXPANSION that provides the types for
14788 the parameters in this function parameter pack. */
14792 {
14795 /* Zero-length parameter packs are boring. Just substitute
14796 into the chain. */
14800 }
14801 else
14802 {
14803 /* All we did was update the type. Make a note of that. */
14806 }
14807 }
14809 /* Loop through all of the parameters we'll build. When T is
14810 a function parameter pack, LEN is the number of expanded
14811 types in EXPANDED_TYPES; otherwise, LEN is 1. */
14814 {
14821 /* We're on the Ith parameter of the function parameter
14822 pack. */
14823 {
14824 /* Get the Ith type. */
14827 /* Rename the parameter to include the index. */
14830 }
14832 /* We're dealing with a normal parameter. */
14840 {
14843 else
14846 }
14857 /* Keep track of the first new parameter we
14858 generate. That's what will be returned to the
14859 caller. */
14863 /* Build a proper chain of parameters when substituting
14864 into a function parameter pack. */
14867 }
14869 /* If cp_unevaluated_operand is set, we're just looking for a
14870 single dummy parameter, so don't keep going. */
14875 /* FIRST_R contains the start of the chain we've built. */
14877 }
14881 {
14888 {
14889 /* This field is a lambda capture pack. Return a TREE_VEC of
14890 the expanded fields to instantiate_class_template_1. */
14894 {
14897 }
14898 else
14899 {
14900 /* All we did was update the type. Make a note of that. */
14903 }
14904 }
14907 {
14910 {
14914 }
14924 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
14925 number of bits. */
14931 {
14932 /* Set up DECL_TEMPLATE_INFO so that we can get at the
14933 NSDMI in perform_member_init. Still set DECL_INITIAL
14934 so that we know there is one. */
14939 }
14940 /* We don't have to set DECL_CONTEXT here; it is set by
14941 finish_member_declaration. */
14950 }
14954 }
14958 /* We reach here only for member using decls. We also need to check
14959 uses_template_parms because DECL_DEPENDENT_P is not set for a
14960 using-declaration that designates a member of the current
14961 instantiation (c++/53549). */
14964 {
14968 {
14973 {
14977 {
14980 }
14981 else
14982 {
14985 }
14987 }
14988 }
14989 else
14990 {
14996 else
14997 {
15000 }
15001 }
15002 }
15003 else
15004 {
15007 }
15012 {
15023 {
15024 /* If this is the canonical decl, we don't have to
15025 mess with instantiations, and often we can't (for
15026 typename, template type parms and such). Note that
15027 TYPE_NAME is not correct for the above test if
15028 we've copied the type for a typedef. */
15034 }
15036 /* Check to see if we already have the specialization we
15037 need. */
15043 {
15046 {
15048 complain,
15051 /* The context and type of an injected-class-name are
15052 the same, so we don't need to substitute both. */
15054 /* If CTX is unchanged, then T is in fact the
15055 specialization we want. That situation occurs when
15056 referencing a static data member within in its own
15057 class. We can use pointer equality, rather than
15058 same_type_p, because DECL_CONTEXT is always
15059 canonical... */
15061 /* ... unless T is a member template; in which
15062 case our caller can be willing to create a
15063 specialization of that template represented
15064 by T. */
15068 }
15071 {
15078 /* We're fully specializing a template declaration, so
15079 we need to coerce the innermost arguments corresponding to
15080 the template. */
15081 argvec = (coerce_innermost_template_parms
15089 }
15090 }
15091 else
15092 {
15094 /* Subsequent calls to pushdecl will fill this in. */
15096 /* A local variable. */
15098 /* Unless this is a reference to a static variable from an
15099 enclosing function, in which case we need to fill it in now. */
15101 {
15105 }
15107 }
15108 /* If we already have the specialization we need, there is
15109 nothing more to do. */
15111 {
15114 }
15116 /* Create a new node for the specialization we need. */
15118 {
15121 else
15131 /* Substituting the type might have recursively instantiated this
15132 same alias (c++/86171). */
15135 {
15138 }
15139 }
15142 {
15148 {
15149 /* It may seem that this case cannot occur, since:
15151 typedef void f();
15152 void g() { f x; }
15154 declares a function, not a variable. However:
15156 typedef void f();
15157 template <typename T> void g() { T t; }
15158 template void g<f>();
15160 is an attempt to declare a variable with function
15161 type. */
15163 /* R is not yet sufficiently initialized, so we
15164 just use its name. */
15167 }
15169 /* Wait until cp_finish_decl to set this again, to handle
15170 circular dependency (template/instantiate6.C). */
15175 {
15177 /* If the DECL_VALUE_EXPR is converted to the declared type,
15178 preserve the identity so that gimplify_type_sizes works. */
15185 {
15188 }
15197 else
15201 }
15205 }
15211 /* Clear out the mangled name and RTL for the instantiation. */
15217 /* The initializer must not be expanded until it is required;
15218 see [temp.inst]. */
15222 {
15228 /* Possibly limit visibility based on template args. */
15231 {
15235 }
15237 }
15240 {
15241 /* A static data member declaration is always marked
15242 external when it is declared in-class, even if an
15243 initializer is present. We mimic the non-template
15244 processing here. */
15253 }
15254 else
15255 {
15260 }
15269 /* Preserve a typedef that names a type. */
15271 {
15275 /* common_handle_aligned_attribute doesn't apply the alignment
15276 to DECL_ORIGINAL_TYPE. */
15280 }
15283 }
15288 }
15289 #undef RETURN
15291 out:
15292 /* Restore the file and line information. */
15296 }
15298 /* Substitute into the complete parameter type list PARMS. */
15300 tree
15302 tree args,
15303 tsubst_flags_t complain,
15304 tree in_decl)
15305 {
15307 }
15309 /* Substitute into the ARG_TYPES of a function type.
15310 If END is a TREE_CHAIN, leave it and any following types
15311 un-substituted. */
15313 static tree
15315 tree args,
15316 tree end,
15317 tsubst_flags_t complain,
15318 tree in_decl)
15319 {
15328 {
15329 /* For a pack expansion, perform substitution on the
15330 entire expression. Later on, we'll handle the arguments
15331 one-by-one. */
15336 /* So that we'll spin through the parameters, one by one. */
15338 else
15339 {
15340 /* We only partially substituted into the parameter
15341 pack. Our type is TYPE_PACK_EXPANSION. */
15344 }
15345 }
15346 else
15349 /* Check if a substituted type is erroneous before substituting into
15350 the rest of the chain. */
15352 {
15359 {
15361 {
15365 }
15367 }
15368 }
15370 /* We do not substitute into default arguments here. The standard
15371 mandates that they be instantiated only when needed, which is
15372 done in build_over_call. */
15375 /* Except that we do substitute default arguments under tsubst_lambda_expr,
15376 since the new op() won't have any associated template arguments for us
15377 to refer to later. */
15390 {
15394 /* Do array-to-pointer, function-to-pointer conversion, and ignore
15395 top-level qualifiers as required. */
15399 {
15400 /* We've instantiated a template before its default arguments
15401 have been parsed. This can happen for a nested template
15402 class, and is not an error unless we require the default
15403 argument in a call of this function. */
15404 remaining_arg_types
15407 remaining_arg_types);
15408 }
15409 else
15410 remaining_arg_types
15412 }
15415 }
15417 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
15418 *not* handle the exception-specification for FNTYPE, because the
15419 initial substitution of explicitly provided template parameters
15420 during argument deduction forbids substitution into the
15421 exception-specification:
15423 [temp.deduct]
15425 All references in the function type of the function template to the
15426 corresponding template parameters are replaced by the specified tem-
15427 plate argument values. If a substitution in a template parameter or
15428 in the function type of the function template results in an invalid
15429 type, type deduction fails. [Note: The equivalent substitution in
15430 exception specifications is done only when the function is instanti-
15431 ated, at which point a program is ill-formed if the substitution
15432 results in an invalid type.] */
15434 static tree
15436 tree args,
15437 tsubst_flags_t complain,
15438 tree in_decl)
15439 {
15440 tree return_type;
15443 /* The TYPE_CONTEXT is not used for function/method types. */
15446 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
15447 failure. */
15451 {
15452 /* Substitute the argument types. */
15464 {
15465 /* DR 1207: 'this' is in scope in the trailing return type. */
15467 }
15469 /* Substitute the return type. */
15473 {
15476 }
15477 }
15478 else
15479 /* Substitute the return type. */
15484 /* DR 486 clarifies that creation of a function type with an
15485 invalid return type is a deduction failure. */
15488 {
15490 {
15493 else
15495 }
15497 }
15500 {
15501 /* Substitute the argument types. */
15506 }
15508 /* Construct a new type node and return it. */
15511 }
15513 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
15514 ARGS into that specification, and return the substituted
15515 specification. If there is no specification, return NULL_TREE. */
15517 static tree
15519 tree args,
15520 tsubst_flags_t complain,
15521 tree in_decl,
15523 {
15524 tree specs;
15525 tree new_specs;
15530 {
15531 /* A noexcept-specifier. */
15536 {
15537 /* Defer instantiation of noexcept-specifiers to avoid
15538 excessive instantiations (c++/49107). */
15541 {
15542 /* We already partially instantiated this member template,
15543 so combine the new args with the old. */
15548 }
15549 else
15550 {
15553 }
15554 }
15555 else
15556 {
15558 {
15560 args);
15562 }
15563 new_specs = tsubst_copy_and_build
15566 }
15568 /* We've instantiated a template before a noexcept-specifier
15569 contained therein has been parsed. This can happen for
15570 a nested template class:
15572 struct S {
15573 template<typename> struct B { B() noexcept(...); };
15574 struct A : B<int> { ... use B() ... };
15575 };
15577 where completing B<int> will trigger instantiating the
15578 noexcept, even though we only parse it at the end of S. */
15580 {
15583 }
15584 }
15586 {
15589 else
15591 {
15592 tree spec;
15597 {
15598 /* Expand the pack expansion type. */
15601 in_decl);
15607 else
15608 {
15609 /* We're substituting into a member template, so
15610 we got a TYPE_PACK_EXPANSION back. Add that
15611 expansion and move on. */
15615 expanded_specs,
15616 complain);
15619 }
15620 }
15623 {
15626 else
15631 complain);
15632 }
15635 }
15636 }
15638 }
15640 /* Substitute through a TREE_LIST of types or expressions, handling pack
15641 expansions. */
15643 tree
15645 {
15652 ;
15654 {
15658 }
15661 else
15669 ;
15671 {
15675 }
15678 else
15685 ;
15690 else
15701 /* Determine the number of arguments. */
15703 {
15706 }
15709 else
15713 {
15721 else
15723 }
15726 }
15728 /* Take the tree structure T and replace template parameters used
15729 therein with the argument vector ARGS. IN_DECL is an associated
15730 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
15731 Issue error and warning messages under control of COMPLAIN. Note
15732 that we must be relatively non-tolerant of extensions here, in
15733 order to preserve conformance; if we allow substitutions that
15734 should not be allowed, we may allow argument deductions that should
15735 not succeed, and therefore report ambiguous overload situations
15736 where there are none. In theory, we could allow the substitution,
15737 but indicate that it should have failed, and allow our caller to
15738 make sure that the right thing happens, but we don't try to do this
15739 yet.
15741 This function is used for dealing with types, decls and the like;
15742 for expressions, use tsubst_expr or tsubst_copy. */
15744 tree
15746 {
15775 /* Reuse typedefs. We need to do this to handle dependent attributes,
15776 such as attribute aligned. */
15779 {
15783 {
15784 /* DECL represents an alias template and we want to
15785 instantiate it. */
15789 }
15793 {
15797 }
15802 else
15803 /* The typedef is from a non-template context. */
15807 {
15809 r = cp_build_qualified_type
15813 }
15814 else
15815 {
15816 /* We don't have an instantiation yet, so drop the typedef. */
15821 }
15822 }
15842 {
15869 {
15875 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
15876 needed. */
15882 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
15883 with TREE_SIDE_EFFECTS that indicates this is not an integral
15884 constant expression. */
15887 {
15890 }
15893 }
15897 {
15905 else
15907 }
15908 /* Fall through. */
15912 {
15926 {
15929 /* See through ARGUMENT_PACK_SELECT arguments. */
15932 }
15937 {
15939 /* If ARG is an argument pack, we don't actually want to
15940 perform a substitution here, because substitutions
15941 for argument packs are only done
15942 element-by-element. We can get to this point when
15943 substituting the type of a non-type template
15944 parameter pack, when that type actually contains
15945 template parameter packs from an outer template, e.g.,
15947 template<typename... Types> struct A {
15948 template<Types... Values> struct B { };
15949 }; */
15953 {
15956 /* When building concept checks for the purpose of
15957 deducing placeholders, we can end up with wildcards
15958 where types are expected. Adjust this to the deduced
15959 value. */
15967 return cp_build_qualified_type
15969 }
15971 {
15972 /* We are processing a type constructed from a
15973 template template parameter. */
15984 /* Consider this code:
15986 template <template <class> class Template>
15987 struct Internal {
15988 template <class Arg> using Bind = Template<Arg>;
15989 };
15991 template <template <class> class Template, class Arg>
15992 using Instantiate = Template<Arg>; //#0
15994 template <template <class> class Template,
15995 class Argument>
15996 using Bind =
15997 Instantiate<Internal<Template>::template Bind,
15998 Argument>; //#1
16000 When #1 is parsed, the
16001 BOUND_TEMPLATE_TEMPLATE_PARM representing the
16002 parameter `Template' in #0 matches the
16003 UNBOUND_CLASS_TEMPLATE representing the argument
16004 `Internal<Template>::template Bind'; We then want
16005 to assemble the type `Bind<Argument>' that can't
16006 be fully created right now, because
16007 `Internal<Template>' not being complete, the Bind
16008 template cannot be looked up in that context. So
16009 we need to "store" `Bind<Argument>' for later
16010 when the context of Bind becomes complete. Let's
16011 store that in a TYPENAME_TYPE. */
16015 argvec),
16016 typename_type,
16017 complain);
16019 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
16020 are resolving nested-types in the signature of a
16021 member function templates. Otherwise ARG is a
16022 TEMPLATE_DECL and is the real template to be
16023 instantiated. */
16031 complain);
16032 return cp_build_qualified_type
16034 }
16037 else
16038 /* TEMPLATE_PARM_INDEX. */
16040 }
16043 /* This can happen during the attempted tsubst'ing in
16044 unify. This means that we don't yet have any information
16045 about the template parameter in question. */
16048 /* Early in template argument deduction substitution, we don't
16049 want to reduce the level of 'auto', or it will be confused
16050 with a normal template parm in subsequent deduction.
16051 Similarly, don't reduce the level of template parameters to
16052 avoid mismatches when deducing their types. */
16056 /* If we get here, we must have been looking at a parm for a
16057 more deeply nested template. Make a new version of this
16058 template parameter, but with a lower level. */
16060 {
16065 {
16067 r = cp_build_qualified_type
16071 }
16078 /* Break infinite recursion when substituting the constraints
16086 /* Cache the simple case of lowering a type parameter. */
16088 else
16089 {
16101 /* Propagate constraints on placeholders since they are
16102 only instantiated during satisfaction. */
16106 {
16108 /* We might need to substitute into the types of non-type
16109 template parameters. */
16121 }
16125 else
16127 }
16131 /* OK, now substitute the type of the non-type parameter. We
16132 couldn't do it earlier because it might be an auto parameter,
16133 and we wouldn't need to if we had an argument. */
16142 }
16145 }
16151 /* We should never be tsubsting a binfo. */
16155 /* A vector of template arguments. */
16161 {
16165 /* [temp.deduct]
16167 Type deduction may fail for any of the following
16168 reasons:
16170 -- Attempting to create a pointer to reference type.
16171 -- Attempting to create a reference to a reference type or
16172 a reference to void.
16174 Core issue 106 says that creating a reference to a reference
16175 during instantiation is no longer a cause for failure. We
16176 only enforce this check in strict C++98 mode. */
16180 {
16183 /* We keep track of the last time we issued this error
16184 message to avoid spewing a ton of messages during a
16185 single bad template instantiation. */
16188 {
16193 else
16196 }
16199 }
16203 {
16205 {
16208 type);
16209 else
16211 type);
16212 }
16214 }
16216 {
16220 }
16222 /* In C++0x, during template argument substitution, when there is an
16223 attempt to create a reference to a reference type, reference
16224 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
16226 "If a template-argument for a template-parameter T names a type
16227 that is a reference to a type A, an attempt to create the type
16228 'lvalue reference to cv T' creates the type 'lvalue reference to
16229 A,' while an attempt to create the type type rvalue reference to
16230 cv T' creates the type T"
16231 */
16232 r = cp_build_reference_type
16235 else
16240 /* Will this ever be needed for TYPE_..._TO values? */
16244 }
16246 {
16249 {
16250 /* [temp.deduct]
16252 Type deduction may fail for any of the following
16253 reasons:
16255 -- Attempting to create "pointer to member of T" when T
16256 is not a class type. */
16260 }
16262 {
16266 }
16268 {
16272 }
16275 {
16276 /* The type of the implicit object parameter gets its
16277 cv-qualifiers from the FUNCTION_TYPE. */
16278 tree memptr;
16279 tree method_type
16284 complain);
16285 }
16286 else
16289 complain);
16290 }
16293 {
16294 tree fntype;
16295 tree specs;
16300 /* Substitute the exception specification. */
16308 }
16310 {
16315 /* As an optimization, we avoid regenerating the array type if
16316 it will obviously be the same as T. */
16320 /* These checks should match the ones in create_array_type_for_decl.
16322 [temp.deduct]
16324 The deduction may fail for any of the following reasons:
16326 -- Attempting to create an array with an element type that
16327 is void, a function type, or a reference type, or [DR337]
16328 an abstract class type. */
16334 {
16338 }
16351 {
16354 }
16357 }
16360 {
16363 {
16369 {
16374 }
16376 }
16377 else
16389 {
16393 }
16395 {
16396 /* Normally, make_typename_type does not require that the CTX
16397 have complete type in order to allow things like:
16399 template <class T> struct S { typename S<T>::X Y; };
16401 But, such constructs have already been resolved by this
16402 point, so here CTX really should have complete type, unless
16403 it's a partial instantiation. */
16406 }
16415 {
16418 }
16421 {
16423 {
16427 else
16429 }
16431 {
16435 else
16437 }
16438 }
16440 return cp_build_qualified_type
16442 }
16445 {
16457 }
16460 {
16461 tree type;
16477 complain);
16478 }
16481 {
16482 tree type;
16501 else
16502 {
16506 /* In a template ~id could be either a complement expression
16507 or an unqualified-id naming a destructor; if instantiating
16508 it produces an expression, it's not an id-expression or
16509 member access. */
16512 }
16517 }
16520 {
16524 }
16543 /* We should use one of the expression tsubsts for these codes. */
16549 }
16550 }
16552 /* OLDFNS is a lookup set of member functions from some class template, and
16553 NEWFNS is a lookup set of member functions from NEWTYPE, a specialization
16554 of that class template. Return the subset of NEWFNS which are
16555 specializations of a function from OLDFNS. */
16557 static tree
16559 {
16560 /* Record all member functions from the old lookup set OLDFNS into
16561 VISIBLE_SET. */
16565 {
16567 {
16568 /* Imprecisely handle dependent using-decl by keeping all members
16569 in the new lookup set that are defined in a base class, i.e.
16570 members that could plausibly have been introduced by this
16571 dependent using-decl.
16572 FIXME: Track which members are introduced by a dependent
16573 using-decl precisely, perhaps by performing another lookup
16574 from the substituted USING_DECL_SCOPE. */
16577 }
16578 else
16580 }
16582 /* Returns true iff (a less specialized version of) FN appeared in
16583 the old lookup set OLDFNS. */
16586 /* FN is a member function from a base class, introduced via a
16587 using-decl; if it might have been introduced by a dependent
16588 using-decl then just conservatively keep it, otherwise look
16589 in the old lookup set for FN exactly. */
16592 /* FN is a member function template from the current class;
16593 look in the old lookup set for the TEMPLATE_DECL from which
16594 it was specialized. */
16596 else
16597 /* FN is a non-template member function from the current class;
16598 look in the old lookup set for the FUNCTION_DECL from which
16599 it was specialized. */
16602 };
16607 {
16610 }
16614 /* Filter out from NEWFNS the member functions that weren't
16615 previously visible according to OLDFNS. */
16620 {
16622 filtered_size++;
16623 }
16629 }
16631 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
16632 expression on the left-hand side of the "." or "->" operator. We
16633 only do the lookup if we had a dependent BASELINK. Otherwise we
16634 adjust it onto the instantiated heirarchy. */
16636 static tree
16639 {
16651 {
16658 }
16666 {
16671 /* See maybe_dependent_member_ref. */
16673 {
16676 template_args);
16679 }
16682 /* Treat as-if non-dependent below. */
16687 complain);
16689 {
16690 /* Filter out from the new lookup set those functions which didn't
16691 appear in the original lookup set (in a less specialized form).
16692 This is needed to preserve the consistency of member lookup
16693 performed in an incomplete-class context, within which
16694 later-declared members ought to remain invisible. */
16697 binfo_type);
16699 }
16702 {
16708 }
16711 }
16712 else
16713 {
16714 /* We're going to overwrite pieces below, make a duplicate. */
16718 {
16719 /* The decl we found was from non-dependent scope, but we still need
16720 to update the binfos for the instantiated qualifying_scope. */
16724 }
16725 }
16727 /* If lookup found a single function, mark it as used at this point.
16728 (If lookup found multiple functions the one selected later by
16729 overload resolution will be marked as used at that point.) */
16731 {
16737 /* We might have instantiated an auto function. */
16739 }
16742 {
16743 /* Add back the template arguments, if present. */
16748 /* Update the conversion operator type. */
16750 }
16756 {
16758 qualifying_scope,
16759 object_type);
16761 /* We need to call adjust_result_of_qualified_name_lookup in case the
16762 destructor names a base class, but we unset BASELINK_QUALIFIED_P
16763 so that we still get virtual function binding. */
16765 }
16768 }
16770 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
16771 true if the qualified-id will be a postfix-expression in-and-of
16772 itself; false if more of the postfix-expression follows the
16773 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
16774 of "&". */
16776 static tree
16780 {
16781 tree expr;
16782 tree scope;
16783 tree name;
16785 tree template_args;
16790 /* Figure out what name to look up. */
16793 {
16802 }
16803 else
16804 {
16807 }
16809 /* Substitute into the qualifying scope. When there are no ARGS, we
16810 are just trying to simplify a non-dependent expression. In that
16811 case the qualifying scope may be dependent, and, in any case,
16812 substituting will not help. */
16815 {
16818 }
16819 else
16823 {
16825 /* We built one in tsubst_baselink. */
16827 else
16828 {
16831 template_args);
16833 QUALIFIED_NAME_IS_TEMPLATE
16835 }
16838 }
16841 {
16843 {
16844 /* A BIT_NOT_EXPR is used to represent a destructor. */
16846 {
16850 }
16851 else
16854 }
16855 else
16859 {
16861 {
16865 }
16867 }
16868 }
16871 {
16875 /* Remember that there was a reference to this entity. */
16878 }
16881 {
16887 }
16890 {
16891 /* We may be repeating a check already done during parsing, but
16892 if it was well-formed and passed then, it will pass again
16893 now, and if it didn't, we wouldn't have got here. The case
16894 we want to catch is when we couldn't tell then, and can now,
16895 namely when templ prior to substitution was an
16896 identifier. */
16902 complain);
16903 else
16905 }
16911 {
16912 expr = (adjust_result_of_qualified_name_lookup
16914 expr = (finish_qualified_id_expr
16918 }
16920 /* Expressions do not generally have reference type. */
16922 /* However, if we're about to form a pointer-to-member, we just
16923 want the referenced member referenced. */
16933 }
16935 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
16936 initializer, DECL is the substituted VAR_DECL. Other arguments are as
16937 for tsubst. */
16939 static tree
16942 {
16951 {
16953 {
16955 {
16960 }
16961 }
16963 {
16964 /* If we had an initializer but it
16965 instantiated to nothing,
16966 value-initialize the object. This will
16967 only occur when the initializer was a
16968 pack expansion where the parameter packs
16969 used in that expansion were of length
16970 zero. */
16976 }
16977 }
16980 }
16982 /* If T is a reference to a dependent member of the current instantiation C and
16983 we are trying to refer to that member in a partial instantiation of C,
16984 return a SCOPE_REF; otherwise, return NULL_TREE.
16986 This can happen when forming a C++17 deduction guide, as in PR96199. */
16988 static tree
16990 tree in_decl)
16991 {
17008 {
17017 complain);
17018 }
17023 {
17029 }
17032 {
17035 /* The TYPE_DECL for a typename has DECL_CONTEXT of the typename
17036 scope, but it doesn't need to be rewritten again. */
17040 }
17044 else
17047 }
17049 /* Like tsubst, but deals with expressions. This function just replaces
17050 template parms; to finish processing the resultant expression, use
17051 tsubst_copy_and_build or tsubst_expr. */
17053 static tree
17055 {
17057 tree r;
17068 {
17073 {
17074 /* We get here for a use of 'this' in an NSDMI. */
17078 /* This can happen for a parameter name used later in a function
17079 declaration (such as in a late-specified return type). Just
17080 make a dummy decl, since it's only used for its type. */
17083 /* Give it the template pattern as its context; its true context
17084 hasn't been instantiated yet and this is good enough for
17085 mangling. */
17087 }
17096 {
17097 tree enum_type;
17098 tree v;
17102 /* There is no need to substitute into namespace-scope
17103 enumerators. */
17106 /* If ARGS is NULL, then T is known to be non-dependent. */
17110 /* Unfortunately, we cannot just call lookup_name here.
17111 Consider:
17113 template <int I> int f() {
17114 enum E { a = I };
17115 struct S { void g() { E e = a; } };
17116 };
17118 When we instantiate f<7>::S::g(), say, lookup_name is not
17119 clever enough to find f<7>::a. */
17120 enum_type
17130 /* We didn't find the name. That should never happen; if
17131 name-lookup found it during preliminary parsing, we
17132 should find it again here during instantiation. */
17134 }
17139 {
17140 tree ctx;
17145 {
17148 {
17152 }
17154 }
17155 }
17164 {
17165 /* Local specialization will usually have been created when
17166 we instantiated the DECL_EXPR_DECL. */
17169 {
17170 /* We're in a generic lambda referencing a local extern
17171 from an outer block-scope of a non-template. */
17174 }
17175 }
17178 {
17181 {
17182 /* First try name lookup to find the instantiation. */
17185 {
17187 {
17188 /* During error-recovery we may find a non-variable,
17189 even an OVERLOAD: just bail out and avoid ICEs and
17190 duplicate diagnostics (c++/62207). */
17193 }
17195 {
17196 /* Make sure the one we found is the one we want. */
17200 }
17201 }
17205 else
17206 {
17207 /* This can happen for a variable used in a
17208 late-specified return type of a local lambda, or for a
17209 local static or constant. Building a new VAR_DECL
17210 should be OK in all those cases. */
17213 /* Avoid infinite recursion (79640). */
17216 {
17217 /* We can't call cp_finish_decl, so handle the
17218 initializer by hand. */
17233 }
17240 }
17241 /* Remember this for subsequent uses. */
17244 }
17247 }
17248 else
17272 {
17273 /* Template template argument like the following example need
17274 special treatment:
17276 template <template <class> class TT> struct C {};
17277 template <class T> struct D {
17278 template <class U> struct E {};
17279 C<E> c; // #1
17280 };
17281 D<int> d; // #2
17283 We are processing the template argument `E' in #1 for
17284 the template instantiation #2. Originally, `E' is a
17285 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
17286 have to substitute this with one having context `D<int>'. */
17290 }
17291 else
17292 /* Ordinary template template argument. */
17297 {
17298 /* Handle location wrappers by substituting the wrapped node
17299 first, *then* reusing the resulting type. Doing the type
17300 first ensures that we handle template parameters and
17301 parameter pack expansions. */
17303 {
17307 }
17311 {
17312 /* Wrapper to make a C++20 template parameter object const. */
17315 {
17316 /* The template argument is not const, presumably because
17317 it is still dependent, and so not the const template parm
17318 object. */
17324 {
17325 /* Don't add a wrapper to these. */
17328 }
17329 else
17330 /* Do add a wrapper otherwise (in particular, if op is
17331 another TEMPLATE_PARM_INDEX). */
17333 }
17335 }
17336 /* force_paren_expr can also create a VIEW_CONVERT_EXPR. */
17338 {
17343 }
17344 /* We shouldn't see any other uses of these in templates. */
17346 }
17354 CASE_CONVERT:
17355 {
17362 }
17365 {
17371 }
17376 {
17385 /* We only want to compute the number of arguments. */
17388 else
17395 {
17397 /* Set TREE_USED for the benefit of -Wunused. */
17401 }
17409 {
17414 else
17422 else
17427 }
17428 else
17430 }
17432 {
17440 }
17441 /* Fall through */
17457 {
17463 /* For addresses of immediate functions ensure we have EXPR_LOCATION
17464 set for possible later diagnostics. */
17471 }
17474 {
17475 tree object;
17476 tree name;
17481 {
17485 }
17488 {
17498 }
17503 in_decl);
17504 else
17507 }
17543 {
17547 }
17550 {
17555 }
17558 {
17562 }
17565 {
17573 }
17579 {
17586 }
17589 {
17596 }
17599 {
17606 }
17609 {
17610 /* Substituted template arguments */
17620 else
17622 }
17625 {
17645 }
17670 /* Fall through. */
17673 {
17676 }
17677 else
17681 /* This is handled by tsubst_copy_and_build. */
17685 {
17689 }
17692 /* We shouldn't have built any of these during initial template
17693 generation. Instead, they should be built during instantiation
17694 in response to the saved STMT_IS_FULL_EXPR_P setting. */
17698 {
17708 }
17726 {
17727 /* Instantiate any typedefs in the type. */
17732 }
17735 {
17739 {
17742 }
17744 }
17747 /* These can sometimes show up in a partial instantiation, but never
17748 involve template parms. */
17764 /* ??? There's no point in copying it for now, but maybe some
17765 day it will contain more information, such as a pointer back
17766 to the containing function, inlined copy or so. */
17775 /* We shouldn't get here, but keep going if !flag_checking. */
17779 }
17780 }
17782 /* Helper function for tsubst_omp_clauses, used for instantiation of
17783 OMP_CLAUSE_DECL of clauses. */
17785 static tree
17788 {
17792 /* Handle OpenMP iterators. */
17796 {
17797 tree ret;
17800 else
17801 {
17805 {
17822 }
17826 }
17830 }
17832 /* Handle an OpenMP array section represented as a TREE_LIST (or
17833 OMP_CLAUSE_DOACROSS_KIND). An OMP_CLAUSE_DOACROSS (with a depend
17834 kind of OMP_CLAUSE_DOACROSS_SINK) can also be represented as a
17835 TREE_LIST. We can handle it exactly the same as an array section
17836 (purpose, value, and a chain), even though the nomenclature
17837 (low_bound, length, etc) is different. */
17839 {
17840 tree low_bound
17855 }
17858 /* Undo convert_from_reference tsubst_expr could have called. */
17864 }
17866 /* Like tsubst_copy, but specifically for OpenMP clauses. */
17868 static tree
17871 {
17877 {
17883 {
17886 {
17892 }
17893 /* FALLTHRU */
17924 /* FALLTHRU */
17958 {
17961 {
17968 }
17969 else
17971 }
18001 {
18004 }
18009 else
18012 in_decl,
18041 }
18044 {
18061 /* tsubst_expr on SCOPE_REF results in returning
18062 finish_non_static_data_member result. Undo that here. */
18066 {
18071 {
18075 CASE_CONVERT:
18084 /* FALLTHRU */
18088 }
18089 }
18095 {
18098 {
18101 }
18102 }
18106 }
18107 }
18111 {
18116 {
18119 }
18120 }
18122 }
18124 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
18126 static tree
18128 tree in_decl)
18129 {
18130 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
18150 {
18153 else
18154 {
18158 }
18159 }
18164 #undef RECUR
18165 }
18167 /* Used to temporarily communicate the list of #pragma omp parallel
18168 clauses to #pragma omp for instantiation if they are combined
18169 together. */
18176 /* Substitute one OMP_FOR iterator. */
18178 static bool
18183 {
18184 #define RECUR(NODE) \
18185 tsubst_expr ((NODE), args, complain, in_decl, \
18186 integral_constant_expression_p)
18198 {
18201 {
18206 {
18216 else
18218 {
18220 {
18226 }
18229 }
18230 }
18231 }
18235 }
18237 {
18238 /* We need to jump through some hoops to handle declarations in the
18239 init-statement, since we might need to handle auto deduction,
18240 but we need to keep control of initialization. */
18244 }
18245 else
18246 {
18248 {
18251 {
18255 {
18259 CASE_CONVERT:
18267 {
18270 }
18271 /* FALLTHRU */
18275 }
18276 }
18277 }
18278 else
18280 }
18282 {
18288 }
18289 else
18293 {
18299 NULL_TREE);
18300 else
18302 }
18305 {
18312 {
18317 }
18320 }
18330 {
18332 {
18333 /* Declare the variable, but don't let that initialize it. */
18338 }
18341 {
18345 {
18354 }
18355 else
18359 {
18364 }
18365 else
18369 }
18375 }
18378 {
18379 /* Declare and initialize the variable. */
18382 }
18384 {
18389 {
18391 {
18397 {
18400 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
18405 }
18408 {
18410 decl);
18412 }
18415 {
18417 decl);
18419 }
18420 else
18422 }
18425 }
18427 {
18430 ? OMP_CLAUSE_LASTPRIVATE
18435 {
18438 }
18439 }
18440 }
18443 {
18447 }
18448 else
18452 {
18463 {
18471 }
18472 else
18478 {
18484 }
18488 {
18496 }
18497 else
18503 }
18512 #undef RECUR
18513 }
18515 /* Helper function of tsubst_expr, find OMP_TEAMS inside
18516 of OMP_TARGET's body. */
18518 static tree
18520 {
18523 {
18532 }
18534 }
18536 /* Helper function for tsubst_expr. For decomposition declaration
18537 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
18538 also the corresponding decls representing the identifiers
18539 of the decomposition declaration. Return DECL if successful
18540 or error_mark_node otherwise, set *FIRST to the first decl
18541 in the list chained through DECL_CHAIN and *CNT to the number
18542 of such decls. */
18544 static tree
18548 {
18553 decl2
18558 {
18560 {
18563 }
18575 else
18576 {
18580 }
18587 {
18590 }
18591 else
18593 }
18596 }
18598 /* Return the proper local_specialization for init-capture pack DECL. */
18600 static tree
18602 {
18603 /* We handle normal pack captures by forwarding to the specialization of the
18604 captured parameter. We can't do that for pack init-captures; we need them
18605 to have their own local_specialization. We created the individual
18606 VAR_DECLs (if any) under build_capture_proxy, and we need to collect them
18607 when we process the DECL_EXPR for the pack init-capture in the template.
18608 So, how do we find them? We don't know the capture proxy pack when
18609 building the individual resulting proxies, and we don't know the
18610 individual proxies when instantiating the pack. What we have in common is
18611 the FIELD_DECL.
18613 So...when we instantiate the FIELD_DECL, we stick the result in
18614 local_specializations. Then at the DECL_EXPR we look up that result, see
18615 how many elements it has, synthesize the names, and look them up. */
18629 {
18634 }
18636 {
18641 else
18643 }
18645 }
18647 /* T is an operand of a template tree being substituted. Return whether
18648 T is dependent such that we should suppress some warnings that would
18649 make sense if the substituted expression were written directly, like
18650 template <int I> bool f() { return I == 2; }
18651 We don't want to warn when instantiating f that comparing two constants
18652 always has the same value.
18654 This is a more limited concept of dependence than instantiation-dependent;
18655 here we don't care whether substitution could fail. */
18657 static bool
18659 {
18668 }
18670 /* Like tsubst_copy for expressions, etc. but also does semantic
18671 processing. */
18673 tree
18676 {
18677 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
18678 #define RECUR(NODE) \
18679 tsubst_expr ((NODE), args, complain, in_decl, \
18680 integral_constant_expression_p)
18683 tree r;
18684 location_t loc;
18696 {
18698 {
18702 }
18731 else
18740 {
18742 tree init;
18748 {
18751 {
18755 {
18760 }
18762 }
18763 else
18764 {
18765 /* This is a non-dependent using-decl, and we'll have
18766 used the names it found during template parsing. We do
18767 not want to do the lookup again, because we might not
18768 find the things we found then. */
18771 /* We still need to push the bindings so that we can look up
18772 this name later. */
18775 }
18776 }
18779 {
18780 /* We're in tsubst_lambda_expr, we've already inserted a new
18781 capture proxy, so look it up and register it. */
18782 tree inst;
18784 {
18788 }
18790 {
18791 inst = (retrieve_local_specialization
18795 }
18796 else
18801 }
18808 /* Don't copy the old closure; we'll create a new one in
18809 tsubst_lambda_expr. */
18811 else
18812 {
18816 {
18817 /* By marking the declaration as instantiated, we avoid
18818 trying to instantiate it. Since instantiate_decl can't
18819 handle local variables, and since we've already done
18820 all that needs to be done, that's the right thing to
18821 do. */
18826 /* Anonymous aggregates are a special case. */
18829 {
18832 {
18836 }
18838 }
18843 {
18851 }
18852 else
18853 {
18870 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
18876 /* In a non-template function, VLA type declarations are
18877 handled in grokdeclarator; for templates, handle them
18878 now. */
18882 {
18886 asmspec_tree
18890 }
18896 }
18897 }
18898 }
18901 }
18911 {
18915 }
18920 {
18921 /* Construct another range_for, if this is not a final
18922 substitution (for inside a generic lambda of a
18923 template). Otherwise convert to a regular for. */
18925 stmt = (processing_template_decl
18942 {
18948 }
18949 else
18950 {
18956 }
18962 }
18969 {
18973 }
18979 {
18983 }
18995 {
19001 }
19004 {
19005 /* We're partially instantiating a generic lambda, but the condition
19006 of the constexpr if is still dependent. Don't substitute into the
19007 branches now, just remember the template arguments. */
19015 }
19019 {
19024 }
19025 else
19026 {
19034 }
19040 {
19050 }
19058 else
19066 else
19087 {
19093 {
19098 }
19099 }
19103 {
19105 tree label;
19112 }
19118 /* Computed goto's must be tsubst'd into. On the other hand,
19119 non-computed gotos must not be; the identifier in question
19120 will have no binding. */
19122 else
19128 {
19145 }
19150 {
19155 }
19156 else
19157 {
19162 else
19169 else
19175 else
19177 }
19181 {
19185 {
19187 /* Prevent instantiate_decl from trying to instantiate
19188 this variable. We've already done all that needs to be
19189 done. */
19192 }
19197 }
19203 {
19204 /* Local classes are not independent templates; they are
19205 instantiated along with their containing function. And this
19206 way we don't have to deal with pushing out of one local class
19207 to instantiate a member of another local class. */
19208 /* Closures are handled by the LAMBDA_EXPR. */
19218 }
19222 {
19223 tree condition;
19226 condition =
19228 args,
19237 }
19244 in_decl);
19266 {
19273 }
19289 {
19303 in_decl);
19305 {
19312 }
19323 any_range_for
19327 integral_constant_expression_p);
19331 {
19340 }
19341 else
19346 else
19353 else
19354 {
19362 }
19365 t));
19367 }
19373 /* FALLTHRU */
19383 in_decl);
19385 {
19390 }
19391 else
19392 {
19396 }
19401 {
19403 "%<#pragma omp critical%> with %<hint%> clause requires "
19406 }
19417 {
19420 {
19425 }
19426 else
19427 {
19431 }
19433 }
19434 else
19436 OMP_CLAUSE_DEPEND_INVALID,
19445 ? C_ORT_ACC
19464 {
19467 /* For combined target teams, ensure the num_teams and
19468 thread_limit clause expressions are evaluated on the host,
19469 before entering the target construct. */
19478 {
19481 tf_none);
19488 OMP_CLAUSE_FIRSTPRIVATE);
19492 }
19493 }
19530 {
19534 }
19535 else
19546 /* FALLTHRU */
19564 {
19570 {
19573 }
19575 {
19579 {
19582 }
19587 }
19588 else
19589 {
19592 }
19597 }
19598 else
19599 {
19606 {
19609 }
19612 {
19617 {
19620 }
19622 {
19626 {
19629 }
19634 }
19635 else
19636 {
19639 }
19643 }
19644 else
19645 {
19649 }
19653 }
19657 {
19663 {
19667 {
19672 }
19676 }
19677 else
19678 {
19683 }
19684 }
19688 {
19692 }
19705 /* If the first operand was a statement, we're done with it. */
19710 complain));
19727 integral_constant_expression_p));
19728 }
19731 out:
19734 #undef RECUR
19735 #undef RETURN
19736 }
19738 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
19739 function. For description of the body see comment above
19740 cp_parser_omp_declare_reduction_exprs. */
19742 static void
19744 {
19750 tree_stmt_iterator tsi;
19761 {
19768 /* tsubsting a local var_decl leaves DECL_CONTEXT null, as we
19769 expect to be pushing it. */
19781 }
19783 {
19803 }
19804 }
19806 /* T is a postfix-expression that is not being used in a function
19807 call. Return the substituted version of T. */
19809 static tree
19811 tsubst_flags_t complain,
19812 tree in_decl)
19813 {
19817 else
19823 }
19825 /* Subroutine of tsubst_lambda_expr: add the FIELD/INIT capture pair to the
19826 LAMBDA_EXPR_CAPTURE_LIST passed in LIST. Do deduction for a previously
19827 dependent init-capture. */
19829 static void
19831 tsubst_flags_t complain)
19832 {
19834 {
19837 {
19841 }
19848 }
19850 }
19852 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
19853 instantiation context. Instantiating a pack expansion containing a lambda
19854 might result in multiple lambdas all based on the same lambda in the
19855 template. */
19857 tree
19859 {
19874 else
19885 {
19890 else
19903 {
19904 /* For a VLA, simply tsubsting the field type won't work, we need to
19905 go through add_capture again. XXX do we want to do this for all
19906 captures? */
19907 tree name = (get_identifier
19915 }
19922 {
19923 /* Remember these for when we've pushed local_specializations. */
19926 }
19932 {
19940 complain);
19941 }
19942 else
19943 {
19945 complain);
19949 }
19950 }
19957 {
19958 /* A lambda in a default argument outside a class gets no
19959 LAMBDA_EXPR_EXTRA_SCOPE, as specified by the ABI. But
19960 tsubst_default_argument calls start_lambda_scope, so we need to
19961 specifically ignore it here, and use the global scope. */
19964 /* If we're pushed into another scope (PR105652), fix it. */
19968 }
19969 else
19972 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
19990 else
19991 {
19992 /* The body of a lambda-expression is not a subexpression of the
19993 enclosing expression. Parms are to have DECL_CHAIN tsubsted,
19994 which would be skipped if cp_unevaluated_operand. */
19995 cp_evaluated ev;
19997 /* Fix the type of 'this'. */
20003 {
20006 {
20009 }
20012 }
20013 else
20014 {
20018 {
20021 }
20023 }
20025 /* Let finish_function set this. */
20031 else
20032 /* Still increment function_depth so that we don't GC in the
20033 middle of an expression. */
20043 /* Now record them for lookup_init_capture_pack. */
20046 {
20050 }
20056 {
20057 /* We might not partially instantiate some parts of the function, so
20058 copy these flags from the original template. */
20064 }
20066 /* [temp.deduct] A lambda-expression appearing in a function type or a
20067 template parameter is not considered part of the immediate context for
20068 the purposes of template argument deduction. */
20073 /* We already have a body block from start_lambda_function, we don't
20074 need another to confuse NRV (91217). */
20085 else
20088 /* The capture list was built up in reverse order; fix that now. */
20095 }
20097 out:
20103 }
20105 /* Subroutine of maybe_fold_fn_template_args. */
20107 static bool
20109 {
20112 {
20118 {
20121 }
20126 {
20130 }
20131 }
20134 }
20136 /* Try to do constant evaluation of any explicit template arguments in FN
20137 before overload resolution, to get any errors only once. Return true iff
20138 we didn't have any problems folding. */
20140 static bool
20142 {
20160 }
20162 /* Helper function for tsubst_copy_and_build CALL_EXPR and ARRAY_REF
20163 handling. */
20165 static void
20167 tree in_decl,
20170 {
20173 {
20180 integral_constant_expression_p));
20181 else
20182 {
20183 /* Expand the pack expansion and push each entry onto CALL_ARGS. */
20186 {
20191 {
20196 }
20197 }
20198 else
20199 /* A partial substitution. Add one entry. */
20201 }
20202 }
20203 }
20205 /* Like tsubst but deals with expressions and performs semantic
20206 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)" or
20207 "F<TARGS> (ARGS)". */
20209 tree
20211 tree args,
20212 tsubst_flags_t complain,
20213 tree in_decl,
20216 {
20217 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
20218 #define RECUR(NODE) \
20219 tsubst_copy_and_build (NODE, args, complain, in_decl, \
20221 integral_constant_expression_p)
20224 location_t save_loc;
20233 /* N3276 decltype magic only applies to calls at the top level or on the
20234 right side of a comma. */
20239 {
20242 /* Fall through. */
20244 {
20245 tree decl;
20246 cp_id_kind idk;
20251 {
20254 }
20256 /* Look up the name. */
20259 /* By convention, expressions use ERROR_MARK_NODE to indicate
20260 failure, not NULL_TREE. */
20266 integral_constant_expression_p,
20274 input_location);
20278 {
20282 }
20284 }
20287 {
20288 tree object;
20291 function_p,
20292 integral_constant_expression_p);
20301 {
20306 }
20309 {
20316 /* If we built a function concept check, return the underlying
20317 template-id. So we can evaluate it as a function call. */
20322 }
20325 {
20327 complain);
20330 }
20333 {
20336 }
20337 else
20347 {
20348 /* C++20 P0846: we can encounter an IDENTIFIER_NODE here when
20349 name lookup found nothing when parsing the template name. */
20352 }
20353 else
20355 }
20358 {
20362 {
20363 /* A type conversion to reference type will be enclosed in
20364 such an indirect ref, but the substitution of the cast
20365 will have also added such an indirect ref. */
20367 }
20368 else
20377 }
20380 {
20384 }
20387 {
20391 {
20396 }
20398 /* We'll pass this to convert_nontype_argument again, we don't need
20399 to actually perform any conversion here. */
20407 flags));
20408 }
20411 {
20417 }
20424 {
20425 tree type;
20434 {
20439 }
20447 {
20467 }
20470 }
20473 {
20477 }
20502 /* convert_like should have created an IMPLICIT_CONV_EXPR. */
20513 else
20515 in_decl);
20550 {
20551 /* If either OP0 or OP1 was value- or type-dependent, suppress
20552 warnings that depend on the range of the types involved. */
20566 tree r = build_x_binary_op
20568 op0,
20570 ? ERROR_MARK
20572 op1,
20574 ? ERROR_MARK
20583 }
20586 {
20594 }
20610 {
20612 releasing_vec index_exp_list;
20614 integral_constant_expression_p,
20615 index_exp_list);
20617 tree r;
20623 else
20628 }
20637 /* Fall through */
20640 {
20641 tree r;
20649 {
20650 /* When there are no ARGS, we are trying to evaluate a
20651 non-dependent expression from the parser. Trying to do
20652 the substitutions may not work. */
20655 }
20656 else
20657 {
20662 else
20665 /*integral_constant_expression_p=*/
20669 }
20674 else
20679 {
20681 {
20683 {
20687 }
20688 else
20692 }
20694 }
20696 }
20699 {
20709 }
20725 {
20730 tree r = build_x_modify_expr
20734 /* TREE_NO_WARNING must be set if either the expression was
20735 parenthesized or it uses an operator such as >>= rather
20736 than plain assignment. In the former case, it was already
20737 set and must be copied. In the latter case,
20738 build_x_modify_expr sets it and it must not be reset
20739 here. */
20744 }
20749 /* Remember that there was a reference to this entity. */
20756 {
20761 tree ret;
20768 else
20769 {
20773 }
20775 /* If there was an initializer in the original tree, but it
20776 instantiated to an empty list, then we should pass a
20777 non-NULL empty vector to tell build_new that it was an
20778 empty initializer() rather than no initializer. This can
20779 only happen when the initializer is a pack expansion whose
20780 parameter packs are of length zero. */
20785 else
20786 {
20790 else
20791 {
20794 }
20795 }
20797 /* Avoid passing an enclosing decl to valid_array_size_p. */
20804 complain);
20812 }
20815 {
20821 complain));
20822 }
20825 {
20829 integral_constant_expression_p);
20831 op0,
20835 }
20838 {
20839 tree function;
20843 tree ret;
20846 /* Internal function with no arguments. */
20850 /* When we parsed the expression, we determined whether or
20851 not Koenig lookup should be performed. */
20854 {
20857 }
20859 {
20864 }
20869 {
20870 /* Do nothing; calling tsubst_copy_and_build on an identifier
20871 would incorrectly perform unqualified lookup again.
20873 Note that we can also have an IDENTIFIER_NODE if the earlier
20874 unqualified lookup found a member function; in that case
20875 koenig_p will be false and we do want to do the lookup
20876 again to find the instantiated member function.
20878 FIXME but doing that causes c++/15272, so we need to stop
20879 using IDENTIFIER_NODE in that situation. */
20883 /* Use tsubst_copy to substitute through the template arguments
20884 of the template-id without performing unqualified lookup of
20885 the template name. */
20887 }
20888 else
20889 {
20891 {
20897 }
20898 else
20903 /* Avoid error about taking the address of a constructor. */
20908 /* When KOENIG_P, we don't want to mark_used the callee before
20909 augmenting the overload set via ADL, so during this initial
20910 substitution we disable mark_used by setting tf_conv (68942). */
20913 in_decl,
20915 integral_constant_expression_p);
20919 }
20922 releasing_vec call_args;
20924 integral_constant_expression_p,
20925 call_args);
20927 /* Stripped-down processing for a call in a thunk. Specifically, in
20928 the thunk template for a generic lambda. */
20930 {
20931 /* Now that we've expanded any packs, the number of call args
20932 might be different. */
20936 {
20943 }
20944 /* We aren't going to do normal overload resolution, so force the
20945 template-id to resolve. */
20948 {
20949 /* In a thunk, pass through args directly, without any
20950 conversions. */
20955 }
20957 {
20958 /* If there are no other args, just push 'this'. */
20961 else
20962 {
20963 /* Otherwise, shift the other args over to make room. */
20969 }
20970 }
20973 /* The thunk location is not interesting. */
20980 }
20982 /* We do not perform argument-dependent lookup if normal
20983 lookup finds a non-function, in accordance with the
20984 resolution of DR 218. */
20987 /* If lookup found a member function, the Koenig lookup is
20988 not appropriate, even if an unqualified-name was used
20989 to denote the function. */
20992 /* C++20 P0846: Lookup found nothing. */
20995 /* Only do this when substitution turns a dependent call
20996 into a non-dependent call. */
21008 {
21013 {
21014 /* For backwards compatibility and good diagnostics, try
21015 the unqualified lookup again if we aren't in SFINAE
21016 context. */
21017 tree unq = (tsubst_copy_and_build
21019 integral_constant_expression_p));
21024 {
21027 "and no declarations were found by "
21028 "argument-dependent lookup at the point "
21033 /* In a lambda fn, we have to be careful to not
21034 introduce new this captures. Legacy code can't
21035 be using lambdas anyway, so it's ok to be
21036 stricter. Be strict with C++20 template-id ADL too. */
21042 else
21046 {
21057 {
21060 "declarations in dependent base %qT are "
21066 else
21070 }
21071 else
21073 "%qD declared here, later in the "
21077 }
21080 }
21081 }
21083 {
21087 }
21088 }
21090 /* Remember that there was a reference to this entity. */
21092 {
21096 /* We should already have called mark_used when taking the
21097 address of this function, but do so again anyway to make
21098 sure it's odr-used: at worst this is a no-op, but if we
21099 obtained this FUNCTION_DECL as part of ahead-of-time overload
21100 resolution then that call to mark_used wouldn't have marked it
21101 odr-used yet (53164). */
21106 }
21111 /* Put back tf_decltype for the actual call. */
21116 {
21120 {
21122 "wrong number of arguments to "
21125 }
21126 else
21134 {
21136 "wrong number of arguments to "
21140 }
21144 complain);
21150 {
21152 complain);
21156 }
21159 /* Unsupported internal function with arguments. */
21161 }
21166 complain);
21168 {
21183 complain);
21184 else
21185 ret = (build_new_method_call
21190 complain));
21191 }
21193 {
21194 /* FUNCTION is a template-id referring to a concept definition. */
21199 /* Calls to standard and variable concepts should have been
21200 previously diagnosed. */
21203 /* Ensure the result is wrapped as a call expression. */
21205 }
21206 else
21209 koenig_p,
21210 complain);
21213 {
21219 {
21223 }
21225 /* This also suppresses -Wredundant-move. */
21227 }
21230 }
21233 {
21240 {
21242 {
21247 }
21248 else
21249 {
21254 }
21256 }
21257 else
21258 {
21261 }
21266 }
21269 {
21274 input_location));
21275 }
21281 {
21282 tree object;
21283 tree object_type;
21284 tree member;
21285 tree r;
21289 /* Remember that there was a reference to this entity. */
21300 else
21307 {
21310 }
21312 {
21314 complain);
21318 }
21322 {
21324 {
21329 {
21332 }
21334 {
21339 }
21340 }
21341 }
21344 {
21345 /* Lookup the template functions now that we know what the
21346 scope is. */
21353 {
21356 args);
21357 member = (adjust_result_of_qualified_name_lookup
21359 object_type));
21360 }
21361 else
21362 {
21364 input_location);
21366 }
21367 }
21371 {
21373 {
21377 else
21380 }
21382 }
21386 complain);
21390 }
21397 {
21404 tree r;
21413 /* We do not want to process the index of aggregate
21414 initializers as they are identifier nodes which will be
21415 looked up by digest_init. */
21419 {
21422 }
21427 {
21429 /* An identifier index is looked up in the type
21430 being initialized, not the current scope. */
21435 {
21436 /* Substitute into the pack expansion. */
21438 in_decl);
21442 ;
21444 /* Just move the argument into place. */
21446 else
21447 {
21448 /* Update the length of the final CONSTRUCTOR
21449 arguments vector, and note that we will need to
21450 copy.*/
21453 }
21454 }
21455 else
21457 }
21460 {
21465 {
21467 {
21472 }
21473 else
21475 }
21476 }
21484 {
21489 }
21493 }
21496 {
21499 {
21502 }
21503 else
21504 {
21507 }
21508 }
21513 /* Fall through */
21516 {
21518 /* ??? We're doing a subset of finish_id_expression here. */
21520 /* Replace an evaluated use of the thread_local variable with
21521 a call to its wrapper. */
21527 /* If the original type was a reference, we'll be wrapped in
21528 the appropriate INDIRECT_REF. */
21531 }
21534 {
21538 }
21541 {
21542 tree object_ptr
21549 }
21556 {
21563 }
21566 {
21572 integral_constant_expression_p);
21576 /* If the resulting list of expression statement is empty,
21577 fold it further into void_node. */
21582 }
21585 {
21587 {
21588 /* We don't have a full set of template arguments yet; don't touch
21589 the lambda at all. */
21592 }
21596 }
21600 integral_constant_expression_p));
21605 else
21606 /* Recreate the PAREN_EXPR from __builtin_assoc_barrier. */
21607 {
21611 }
21614 {
21619 complain));
21620 }
21623 {
21626 }
21629 /* No need to substitute further, a RANGE_EXPR will always be built
21630 with constant operands. */
21636 /* We need to do this here as well as in tsubst_copy so we get the
21637 other tsubst_copy_and_build semantics for a PARM_DECL operand. */
21640 /* fallthrough. */
21643 /* Handle Objective-C++ constructs, if appropriate. */
21644 {
21645 tree subst
21650 }
21652 }
21654 #undef RECUR
21655 #undef RETURN
21656 out:
21659 }
21661 /* Verify that the instantiated ARGS are valid. For type arguments,
21662 make sure that the type's linkage is ok. For non-type arguments,
21663 make sure they are constants if they are integral or enumerations.
21664 Emit an error under control of COMPLAIN, and return TRUE on error. */
21666 static bool
21668 {
21672 {
21682 }
21684 {
21685 /* [basic.link]: A name with no linkage (notably, the name
21686 of a class or enumeration declared in a local scope)
21687 shall not be used to declare an entity with linkage.
21688 This implies that names with no linkage cannot be used as
21689 template arguments
21691 DR 757 relaxes this restriction for C++0x. */
21696 {
21697 /* DR 488 makes use of a type with no linkage cause
21698 type deduction to fail. */
21700 {
21703 else
21706 }
21708 }
21709 /* In order to avoid all sorts of complications, we do not
21710 allow variably-modified types as template arguments. */
21712 {
21716 }
21717 }
21718 /* Class template and alias template arguments should be OK. */
21720 ;
21721 /* A non-type argument of integral or enumerated type must be a
21722 constant. */
21727 {
21731 }
21733 }
21735 static bool
21737 {
21742 {
21745 }
21749 }
21751 /* We're out of SFINAE context now, so generate diagnostics for the access
21752 errors we saw earlier when instantiating D from TMPL and ARGS. */
21754 static void
21756 {
21768 }
21770 /* Instantiate the indicated variable, function, or alias template TMPL with
21771 the template arguments in TARG_PTR. */
21773 tree
21775 {
21779 tree fndecl;
21780 tree gen_tmpl;
21781 tree spec;
21792 /* If this function is a clone, handle it specially. */
21794 {
21795 tree spec;
21796 tree clone;
21798 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
21799 DECL_CLONED_FUNCTION. */
21805 /* Look for the clone. */
21809 /* We should always have found the clone by now. */
21812 }
21817 /* Check to see if we already have this specialization. */
21821 /* targ_ptr only has the innermost template args, so add the outer ones
21822 from tmpl, which could be either a partial instantiation or gen_tmpl (in
21823 the case of a non-dependent call within a template definition). */
21824 targ_ptr = (add_outermost_template_args
21826 targ_ptr));
21828 /* It would be nice to avoid hashing here and then again in tsubst_decl,
21829 but it doesn't seem to be on the hot path. */
21833 || ((fndecl
21839 {
21841 {
21845 }
21847 }
21850 complain))
21853 /* We are building a FUNCTION_DECL, during which the access of its
21854 parameters and return types have to be checked. However this
21855 FUNCTION_DECL which is the desired context for access checking
21856 is not built yet. We solve this chicken-and-egg problem by
21857 deferring all checks until we have the FUNCTION_DECL. */
21860 /* Instantiation of the function happens in the context of the function
21861 template, not the context of the overload resolution we're doing. */
21863 /* If there are dependent arguments, e.g. because we're doing partial
21864 ordering, make sure processing_template_decl stays set. */
21868 {
21869 tree ctx;
21871 /* If the context of the partially instantiated template is
21872 already non-dependent, then we might as well use it. */
21874 else
21878 }
21884 {
21885 /* We need to determine if we're using a partial or explicit
21886 specialization now, because the type of the variable could be
21887 different. */
21893 {
21898 }
21899 }
21901 /* Substitute template parameters to obtain the specialization. */
21909 {
21912 }
21914 /* The DECL_TI_TEMPLATE should always be the immediate parent
21915 template, not the most general template. */
21921 /* Now we know the specialization, compute access previously
21922 deferred. Do no access control for inheriting constructors,
21923 as we already checked access for the inherited constructor. */
21926 {
21931 }
21934 /* If we've just instantiated the main entry point for a function,
21935 instantiate all the alternate entry points as well. We do this
21936 by cloning the instantiation of the main entry point, not by
21937 instantiating the template clones. */
21943 {
21945 {
21946 /* Remember to reinstantiate when we're out of SFINAE so the user
21947 can see the errors. */
21949 }
21951 }
21953 }
21955 /* Instantiate the alias template TMPL with ARGS. Also push a template
21956 instantiation level, which instantiate_template doesn't do because
21957 functions and variables have sufficient context established by the
21958 callers. */
21960 static tree
21962 {
21966 args =
21972 /* FIXME check for satisfaction in check_instantiated_args. */
21976 {
21978 {
21979 auto_diagnostic_group d;
21982 }
21984 }
21992 {
21993 /* An alias template specialization can be dependent
21994 even if its underlying type is not. */
21997 /* Sometimes a dependent alias spec is equivalent to its expansion,
21998 sometimes not. So always use structural_comptypes. */
22000 }
22003 }
22005 /* PARM is a template parameter pack for FN. Returns true iff
22006 PARM is used in a deducible way in the argument list of FN. */
22008 static bool
22010 {
22013 {
22015 tree packs;
22021 {
22022 /* The template parameter pack is used in a function parameter
22023 pack. If this is the end of the parameter list, the
22024 template parameter pack is deducible. */
22027 else
22028 /* Otherwise, not. Well, it could be deduced from
22029 a non-pack parameter, but doing so would end up with
22030 a deduction mismatch, so don't bother. */
22032 }
22033 }
22034 /* The template parameter pack isn't used in any function parameter
22035 packs, but it might be used deeper, e.g. tuple<Args...>. */
22037 }
22039 /* Subroutine of fn_type_unification: check non-dependent parms for
22040 convertibility. */
22042 static int
22046 {
22047 /* Non-constructor methods need to leave a conversion for 'this', which
22048 isn't included in nargs here. */
22054 {
22060 /* For a function parameter pack that occurs at the end of the
22061 parameter-declaration-list, the type A of each remaining
22062 argument of the call is compared with the type P of the
22063 declarator-id of the function parameter pack. */
22069 /* For a function parameter pack that does not occur at the
22070 end of the parameter-declaration-list, the type of the
22071 parameter pack is a non-deduced context. */
22075 {
22083 }
22086 }
22089 }
22091 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
22092 NARGS elements of the arguments that are being used when calling
22093 it. TARGS is a vector into which the deduced template arguments
22094 are placed.
22096 Returns either a FUNCTION_DECL for the matching specialization of FN or
22097 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
22098 true, diagnostics will be printed to explain why it failed.
22100 If FN is a conversion operator, or we are trying to produce a specific
22101 specialization, RETURN_TYPE is the return type desired.
22103 The EXPLICIT_TARGS are explicit template arguments provided via a
22104 template-id.
22106 The parameter STRICT is one of:
22108 DEDUCE_CALL:
22109 We are deducing arguments for a function call, as in
22110 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
22111 deducing arguments for a call to the result of a conversion
22112 function template, as in [over.call.object].
22114 DEDUCE_CONV:
22115 We are deducing arguments for a conversion function, as in
22116 [temp.deduct.conv].
22118 DEDUCE_EXACT:
22119 We are deducing arguments when doing an explicit instantiation
22120 as in [temp.explicit], when determining an explicit specialization
22121 as in [temp.expl.spec], or when taking the address of a function
22122 template, as in [temp.deduct.funcaddr]. */
22124 tree
22126 tree explicit_targs,
22127 tree targs,
22130 tree return_type,
22131 unification_kind_t strict,
22136 {
22137 tree parms;
22138 tree fntype;
22143 /* type_unification_real will pass back any access checks from default
22144 template argument substitution. */
22146 /* We don't have all the template args yet. */
22159 full_targs = (add_outermost_template_args
22161 targs));
22166 /* In C++0x, it's possible to have a function template whose type depends
22167 on itself recursively. This is most obvious with decltype, but can also
22168 occur with enumeration scope (c++/48969). So we need to catch infinite
22169 recursion and reject the substitution at deduction time; this function
22170 will return error_mark_node for any repeated substitution.
22172 This also catches excessive recursion such as when f<N> depends on
22173 f<N-1> across all integers, and returns error_mark_node for all the
22174 substitutions back up to the initial one.
22176 This is, of course, not reentrant. */
22185 {
22186 /* [temp.deduct]
22188 The specified template arguments must match the template
22189 parameters in kind (i.e., type, nontype, template), and there
22190 must not be more arguments than there are parameters;
22191 otherwise type deduction fails.
22193 Nontype arguments must match the types of the corresponding
22194 nontype template parameters, or must be convertible to the
22195 types of the corresponding nontype parameters as specified in
22196 _temp.arg.nontype_, otherwise type deduction fails.
22198 All references in the function type of the function template
22199 to the corresponding template parameters are replaced by the
22200 specified template argument values. If a substitution in a
22201 template parameter or in the function type of the function
22202 template results in an invalid type, type deduction fails. */
22213 explicit_targs);
22215 /* Adjust any explicit template arguments before entering the
22216 substitution context. */
22217 explicit_targs
22225 /* Substitute the explicit args into the function type. This is
22226 necessary so that, for instance, explicitly declared function
22227 arguments can match null pointed constants. If we were given
22228 an incomplete set of explicit args, we must not do semantic
22229 processing during substitution as we could create partial
22230 instantiations. */
22232 {
22237 /* Dig out the actual parm. */
22240 {
22243 }
22245 {
22248 }
22251 /* No explicit argument for this template parameter. */
22254 {
22255 /* Mark the argument pack as "incomplete". We could
22256 still deduce more arguments during unification.
22257 We remove this mark in type_unification_real. */
22262 /* We have some incomplete argument packs. */
22264 }
22265 }
22268 {
22270 {
22273 }
22276 /* Ignore any access checks; we'll see them again in
22277 instantiate_template and they might have the wrong
22278 access path at this point. */
22289 }
22291 /* Place the explicitly specified arguments in TARGS. */
22297 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
22299 }
22302 {
22308 }
22313 /* Never do unification on the 'this' parameter. */
22317 {
22318 /* We're deducing for a call to the result of a template conversion
22319 function. The parms we really want are in return_type. */
22323 }
22325 {
22327 }
22329 /* We allow incomplete unification without an error message here
22330 because the standard doesn't seem to explicitly prohibit it. Our
22331 callers must be ready to deal with unification failures in any
22332 event. */
22334 /* If we aren't explaining yet, push tinst context so we can see where
22335 any errors (e.g. from class instantiations triggered by instantiation
22336 of default template arguments) come from. If we are explaining, this
22337 context is redundant. */
22339 {
22342 }
22352 /* Now that we have bindings for all of the template arguments,
22353 ensure that the arguments deduced for the template template
22354 parameters have compatible template parameter lists. We cannot
22355 check this property before we have deduced all template
22356 arguments, because the template parameter types of a template
22357 template parameter might depend on prior template parameters
22358 deduced after the template template parameter. The following
22359 ill-formed example illustrates this issue:
22361 template<typename T, template<T> class C> void f(C<5>, T);
22363 template<int N> struct X {};
22365 void g() {
22366 f(X<5>(), 5l); // error: template argument deduction fails
22367 }
22369 The template parameter list of 'C' depends on the template type
22370 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
22371 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
22372 time that we deduce 'C'. */
22375 {
22378 }
22380 deduced:
22382 /* CWG2369: Check satisfaction before non-deducible conversions. */
22384 {
22388 }
22390 /* DR 1391: All parameters have args, now check non-dependent parms for
22391 convertibility. We don't do this if all args were explicitly specified,
22392 as the standard says that we substitute explicit args immediately. */
22398 /* All is well so far. Now, check:
22400 [temp.deduct]
22402 When all template arguments have been deduced, all uses of
22403 template parameters in nondeduced contexts are replaced with
22404 the corresponding deduced argument values. If the
22405 substitution results in an invalid type, as described above,
22406 type deduction fails. */
22408 {
22411 }
22413 /* Also collect access checks from the instantiation. */
22426 /* Now perform any access checks encountered during substitution. */
22433 /* If we're looking for an exact match, check that what we got
22434 is indeed an exact match. It might not be if some template
22435 parameters are used in non-deduced contexts. But don't check
22436 for an exact match if we have dependent template arguments;
22437 in that case we're doing partial ordering, and we already know
22438 that we have two candidates that will provide the actual type. */
22440 {
22444 tree sarg
22450 {
22454 }
22456 /* add_candidates uses DEDUCE_EXACT for x.operator foo(), but args
22457 doesn't contain the trailing void, and conv fns are always (). */
22459 {
22463 }
22464 }
22466 /* After doing deduction with the inherited constructor, actually return an
22467 instantiation of the inheriting constructor. */
22473 fail:
22476 {
22478 /* Reset once we're all the way out. */
22480 }
22483 }
22485 /* Returns true iff PARM is a forwarding reference in the context of
22486 template argument deduction for TMPL. */
22488 static bool
22490 {
22491 /* [temp.deduct.call], "A forwarding reference is an rvalue reference to a
22492 cv-unqualified template parameter ..." */
22497 {
22499 /* [temp.deduct.call], "... that does not represent a template parameter
22500 of a class template (during class template argument deduction)." */
22504 {
22505 /* Since the template parameters of a synthesized guide consist of
22506 the template parameters of the class template followed by those of
22507 the constructor (if any), we can tell if PARM represents a template
22508 parameter of the class template by comparing its index with the
22509 arity of the class template. */
22514 }
22516 }
22518 }
22520 /* Adjust types before performing type deduction, as described in
22521 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
22522 sections are symmetric. PARM is the type of a function parameter
22523 or the return type of the conversion function. ARG is the type of
22524 the argument passed to the call, or the type of the value
22525 initialized with the result of the conversion function.
22526 ARG_EXPR is the original argument expression, which may be null. */
22528 static int
22530 unification_kind_t strict,
22533 tree arg_expr)
22534 {
22538 {
22543 /* Swap PARM and ARG throughout the remainder of this
22544 function; the handling is precisely symmetric since PARM
22545 will initialize ARG rather than vice versa. */
22550 /* Core issue #873: Do the DR606 thing (see below) for these cases,
22551 too, but here handle it by stripping the reference from PARM
22552 rather than by adding it to ARG. */
22557 /* Nothing else to do in this case. */
22562 }
22565 {
22566 /* [temp.deduct.call]
22568 If P is not a reference type:
22570 --If A is an array type, the pointer type produced by the
22571 array-to-pointer standard conversion (_conv.array_) is
22572 used in place of A for type deduction; otherwise,
22574 --If A is a function type, the pointer type produced by
22575 the function-to-pointer standard conversion
22576 (_conv.func_) is used in place of A for type deduction;
22577 otherwise,
22579 --If A is a cv-qualified type, the top level
22580 cv-qualifiers of A's type are ignored for type
22581 deduction. */
22586 else
22588 }
22590 /* [temp.deduct.call], "If P is a forwarding reference and the argument is
22591 an lvalue, the type 'lvalue reference to A' is used in place of A for
22592 type deduction." */
22595 /* try_one_overload doesn't provide an arg_expr, but
22596 functions are always lvalues. */
22600 /* [temp.deduct.call]
22602 If P is a cv-qualified type, the top level cv-qualifiers
22603 of P's type are ignored for type deduction. If P is a
22604 reference type, the type referred to by P is used for
22605 type deduction. */
22608 {
22611 }
22613 /* DR 322. For conversion deduction, remove a reference type on parm
22614 too (which has been swapped into ARG). */
22619 }
22621 /* Subroutine of fn_type_unification. PARM is a function parameter of a
22622 template which doesn't contain any deducible template parameters; check if
22623 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
22624 unify_one_argument. */
22626 static int
22630 {
22631 tree type;
22635 else
22643 {
22646 }
22648 {
22652 /* Avoid recalculating this in add_function_candidate. */
22653 ok = (*conv_p
22655 else
22659 }
22663 else
22665 }
22669 /* Returns true iff the expression EXPR is one from which a template
22670 argument can be deduced. In other words, if it's an undecorated
22671 use of a template non-type parameter. */
22673 static bool
22675 {
22676 /* Strip implicit conversions and implicit INDIRECT_REFs. */
22682 }
22684 /* Returns true iff the array domain DOMAIN uses a template parameter in a
22685 deducible way; that is, if it has a max value of <PARM> - 1. */
22687 static bool
22689 {
22698 }
22700 /* Returns true iff the template arguments ARGS use a template parameter
22701 in a deducible way. */
22703 static bool
22705 {
22707 {
22711 else
22712 {
22719 else
22721 }
22724 }
22726 }
22728 /* Returns true iff TYPE contains any deducible references to template
22729 parameters, as per 14.8.2.5. */
22731 static bool
22733 {
22737 /* T
22738 cv-list T
22739 TT<T>
22740 TT<i>
22741 TT<> */
22746 /* T*
22747 T&
22748 T&& */
22752 /* T[integer-constant ]
22753 type [i] */
22758 /* T type ::*
22759 type T::*
22760 T T::*
22761 T (type ::*)()
22762 type (T::*)()
22763 type (type ::*)(T)
22764 type (T::*)(T)
22765 T (type ::*)(T)
22766 T (T::*)()
22767 T (T::*)(T) */
22770 || (uses_deducible_template_parms
22773 /* template-name <T> (where template-name refers to a class template)
22774 template-name <i> (where template-name refers to a class template) */
22781 /* type (T)
22782 T()
22783 T(T) */
22785 {
22799 }
22802 }
22804 /* Subroutine of type_unification_real and unify_pack_expansion to
22805 handle unification of a single P/A pair. Parameters are as
22806 for those functions. */
22808 static int
22812 {
22819 /* We can't deduce anything from this, but we might get all the
22820 template args from other function args. */
22823 /* Implicit conversions (Clause 4) will be performed on a function
22824 argument to convert it to the type of the corresponding function
22825 parameter if the parameter type contains no template-parameters that
22826 participate in template argument deduction. */
22829 /* For function parameters with no deducible template parameters,
22830 just return. We'll check non-dependent conversions later. */
22834 {
22836 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
22837 | UNIFY_ALLOW_MORE_CV_QUAL
22851 }
22853 /* We only do these transformations if this is the top-level
22854 parameter_type_list in a call or declaration matching; in other
22855 situations (nested function declarators, template argument lists) we
22856 won't be comparing a type to an expression, and we don't do any type
22857 adjustments. */
22859 {
22861 {
22864 {
22865 /* [temp.deduct.type] A template-argument can be
22866 deduced from a pointer to function or pointer
22867 to member function argument if the set of
22868 overloaded functions does not contain function
22869 templates and at most one of a set of
22870 overloaded functions provides a unique
22871 match. */
22875 /* If a unique match was not found, this is a
22876 non-deduced context, so we still succeed. */
22878 }
22884 }
22888 }
22889 else
22894 /* For deduction from an init-list we need the actual list. */
22898 }
22900 /* for_each_template_parm callback that always returns 0. */
22902 static int
22904 {
22906 }
22908 /* for_each_template_parm any_fn callback to handle deduction of a template
22909 type argument from the type of an array bound. */
22911 static int
22913 {
22921 {
22927 }
22929 /* Keep walking. */
22931 }
22933 /* Try to deduce any not-yet-deduced template type arguments from the type of
22934 an array bound. This is handled separately from unify because 14.8.2.5 says
22935 "The type of a type parameter is only deduced from an array bound if it is
22936 not otherwise deduced." */
22938 static void
22940 {
22945 }
22947 /* Most parms like fn_type_unification.
22949 If SUBR is 1, we're being called recursively (to unify the
22950 arguments of a function or method parameter of a function
22951 template).
22953 CHECKS is a pointer to a vector of access checks encountered while
22954 substituting default template arguments. */
22956 static int
22958 tree full_targs,
22959 tree xparms,
22963 unification_kind_t strict,
22966 {
22971 tree parms;
22982 /* Reset the number of non-defaulted template arguments contained
22983 in TARGS. */
22986 again:
22991 /* Only fn_type_unification cares about terminal void. */
22998 {
23003 /* For a function parameter pack that occurs at the end of the
23004 parameter-declaration-list, the type A of each remaining
23005 argument of the call is compared with the type P of the
23006 declarator-id of the function parameter pack. */
23012 /* For a function parameter pack that does not occur at the
23013 end of the parameter-declaration-list, the type of the
23014 parameter pack is a non-deduced context. */
23021 explain_p))
23023 }
23028 {
23029 /* Unify the remaining arguments with the pack expansion type. */
23030 tree argvec;
23033 /* Allocate a TREE_VEC and copy in all of the arguments */
23038 /* Copy the parameter into parmvec. */
23044 /* Advance to the end of the list of parameters. */
23046 }
23048 /* Fail if we've reached the end of the parm list, and more args
23049 are present, and the parm list isn't variadic. */
23052 /* Fail if parms are left and they don't have default values and
23053 they aren't all deduced as empty packs (c++/57397). This is
23054 consistent with sufficient_parms_p. */
23057 {
23061 do
23062 {
23065 count++;
23067 }
23071 type_pack_p);
23072 }
23075 {
23076 tsubst_flags_t complain = (explain_p
23077 ? tf_warning_or_error
23082 {
23086 /* Clear the "incomplete" flags on all argument packs now so that
23087 substituting them into later default arguments works. */
23089 {
23092 }
23100 {
23105 }
23107 /* If this is an undeduced nontype parameter that depends on
23108 a type parameter, try another pass; its type may have been
23109 deduced from a later argument than the one from which
23110 this parameter can be deduced. */
23115 {
23118 }
23120 /* Core issue #226 (C++0x) [temp.deduct]:
23122 If a template argument has not been deduced, its
23123 default template argument, if any, is used.
23125 When we are in C++98 mode, TREE_PURPOSE will either
23126 be NULL_TREE or ERROR_MARK_NODE, so we do not need
23127 to explicitly check cxx_dialect here. */
23129 /* OK, there is a default argument. Wait until after the
23130 conversion check to do substitution. */
23133 /* If the type parameter is a parameter pack, then it will
23134 be deduced to an empty parameter pack. */
23136 {
23137 tree arg;
23140 {
23143 }
23144 else
23151 }
23154 }
23156 /* Now substitute into the default template arguments. */
23158 {
23175 {
23176 /* The type of this non-type parameter depends on undeduced
23177 parameters. Don't try to use its default argument yet,
23178 since we might deduce an argument for it on the next pass,
23179 but do check whether the arguments we already have cause
23180 substitution failure, so that that happens before we try
23181 later default arguments (78489). */
23184 NULL_TREE);
23188 else
23190 }
23191 else
23192 {
23193 /* Even if the call is happening in template context, getting
23194 here means it's non-dependent, and a default argument is
23195 considered a separate definition under [temp.decls], so we can
23196 do this substitution without processing_template_decl. This
23197 is important if the default argument contains something that
23198 might be instantiation-dependent like access (87480). */
23199 processing_template_decl_sentinel s;
23202 {
23203 /* First instatiate in template context, in case we still
23204 depend on undeduced template parameters. */
23207 NULL_TREE);
23211 /* We replaced all the tparms, substitute again out of
23212 template context. */
23214 }
23217 NULL_TREE);
23224 else
23226 }
23235 {
23237 /* The position of the first default template argument,
23238 is also the number of non-defaulted arguments in TARGS.
23239 Record that. */
23242 }
23243 }
23247 }
23253 }
23255 /* Subroutine of type_unification_real. Args are like the variables
23256 at the call site. ARG is an overloaded function (or template-id);
23257 we try deducing template args from each of the overloads, and if
23258 only one succeeds, we go with that. Modifies TARGS and returns
23259 true on success. */
23261 static bool
23263 tree targs,
23264 tree parm,
23265 tree arg,
23266 unification_kind_t strict,
23269 {
23276 {
23279 }
23280 else
23284 /* Handle `&x' where `x' is some static or non-static member
23285 function name. */
23291 /* Strip baselink information. */
23296 {
23297 /* If we got some explicit template args, we need to plug them into
23298 the affected templates before we try to unify, in case the
23299 explicit args will completely resolve the templates in question. */
23306 {
23319 {
23324 {
23325 /* Instantiate the function to deduce its return type. */
23329 }
23338 {
23341 }
23342 }
23345 }
23346 /* If no templates (or more than one) are fully resolved by the
23347 explicit arguments, this template-id is a non-deduced context; it
23348 could still be OK if we deduce all template arguments for the
23349 enclosing call through other arguments. */
23352 }
23354 /* If ARG is, for example, "(0, &f)" then its type will be unknown
23355 -- but the deduction does not succeed because the expression is
23356 not just the function on its own. */
23358 else
23360 {
23365 {
23368 }
23369 }
23371 /* [temp.deduct.type] A template-argument can be deduced from a pointer
23372 to function or pointer to member function argument if the set of
23373 overloaded functions does not contain function templates and at most
23374 one of a set of overloaded functions provides a unique match.
23376 So if we found multiple possibilities, we return success but don't
23377 deduce anything. */
23380 {
23384 {
23389 /* Don't forget explicit template arguments in a pack. */
23393 }
23394 }
23399 }
23401 /* Core DR 115: In contexts where deduction is done and fails, or in
23402 contexts where deduction is not done, if a template argument list is
23403 specified and it, along with any default template arguments, identifies
23404 a single function template specialization, then the template-id is an
23405 lvalue for the function template specialization. */
23407 tree
23409 {
23422 {
23425 }
23427 {
23430 }
23432 {
23435 }
23438 {
23442 /* If we got some explicit template args, we need to plug them into
23443 the affected templates before we try to unify, in case the
23444 explicit args will completely resolve the templates in question. */
23452 {
23465 {
23468 {
23471 }
23474 {
23477 }
23478 }
23479 }
23481 {
23489 {
23490 tree base
23493 }
23497 }
23499 /* There were no good options and at least one bad one, so let the
23500 user know what the problem is. */
23502 }
23504 }
23506 /* As above, but error out if the expression remains overloaded. */
23508 tree
23510 {
23513 {
23517 }
23519 }
23521 /* Subroutine of resolve_overloaded_unification; does deduction for a single
23522 overload. Fills TARGS with any deduced arguments, or error_mark_node if
23523 different overloads deduce different arguments for a given parm.
23524 ADDR_P is true if the expression for which deduction is being
23525 performed was of the form "& fn" rather than simply "fn".
23527 Returns 1 on success. */
23529 static int
23531 tree orig_targs,
23532 tree targs,
23533 tree parm,
23534 tree arg,
23535 unification_kind_t strict,
23539 {
23541 tree tempargs;
23547 /* [temp.deduct.type] A template-argument can be deduced from a pointer
23548 to function or pointer to member function argument if the set of
23549 overloaded functions does not contain function templates and at most
23550 one of a set of overloaded functions provides a unique match.
23552 So if this is a template, just return success. */
23565 /* We don't copy orig_targs for this because if we have already deduced
23566 some template args from previous args, unify would complain when we
23567 try to deduce a template parameter for the same argument, even though
23568 there isn't really a conflict. */
23575 /* First make sure we didn't deduce anything that conflicts with
23576 explicitly specified args. */
23578 {
23585 /* Since we're unifying against ourselves, we will fill in
23586 template args used in the function parm list with our own
23587 template parms. Discard them. */
23590 {
23591 /* Check that the argument at each index of the deduced argument pack
23592 is equivalent to the corresponding explicitly specified argument.
23593 We may have deduced more arguments than were explicitly specified,
23594 and that's OK. */
23596 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
23597 that's wrong if we deduce the same argument pack from multiple
23598 function arguments: it's only incomplete the first time. */
23611 }
23614 }
23617 {
23622 }
23625 }
23627 /* PARM is a template class (perhaps with unbound template
23628 parameters). ARG is a fully instantiated type. If ARG can be
23629 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
23630 TARGS are as for unify. */
23632 static tree
23635 {
23644 /* We need to make a new template argument vector for the call to
23645 unify. If we used TARGS, we'd clutter it up with the result of
23646 the attempted unification, even if this class didn't work out.
23647 We also don't want to commit ourselves to all the unifications
23648 we've already done, since unification is supposed to be done on
23649 an argument-by-argument basis. In other words, consider the
23650 following pathological case:
23652 template <int I, int J, int K>
23653 struct S {};
23655 template <int I, int J>
23656 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
23658 template <int I, int J, int K>
23659 void f(S<I, J, K>, S<I, I, I>);
23661 void g() {
23662 S<0, 0, 0> s0;
23663 S<0, 1, 2> s2;
23665 f(s0, s2);
23666 }
23668 Now, by the time we consider the unification involving `s2', we
23669 already know that we must have `f<0, 0, 0>'. But, even though
23670 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
23671 because there are two ways to unify base classes of S<0, 1, 2>
23672 with S<I, I, I>. If we kept the already deduced knowledge, we
23673 would reject the possibility I=1. */
23681 else
23691 }
23693 /* Given a template type PARM and a class type ARG, find the unique
23694 base type in ARG that is an instance of PARM. We do not examine
23695 ARG itself; only its base-classes. If there is not exactly one
23696 appropriate base class, return NULL_TREE. PARM may be the type of
23697 a partial specialization, as well as a plain template type. Used
23698 by unify. */
23700 static enum template_base_result
23703 {
23705 tree binfo;
23711 {
23712 /* The type could not be completed. */
23715 }
23717 /* Walk in inheritance graph order. The search order is not
23718 important, and this avoids multiple walks of virtual bases. */
23720 {
23725 {
23726 /* If there is more than one satisfactory baseclass, then:
23728 [temp.deduct.call]
23730 If they yield more than one possible deduced A, the type
23731 deduction fails.
23733 applies. */
23735 {
23736 /* [temp.deduct.call]/4.3: If there is a class C that is a
23737 (direct or indirect) base class of D and derived (directly or
23738 indirectly) from a class B and that would be a valid deduced
23739 A, the deduced A cannot be B or pointer to B, respectively. */
23741 /* Ignore r. */
23745 else
23746 {
23749 }
23750 }
23753 }
23754 }
23758 }
23760 /* Returns the level of DECL, which declares a template parameter. */
23762 static int
23764 {
23766 {
23776 }
23778 }
23780 /* Decide whether ARG can be unified with PARM, considering only the
23781 cv-qualifiers of each type, given STRICT as documented for unify.
23782 Returns nonzero iff the unification is OK on that basis. */
23784 static int
23786 {
23792 {
23793 /* Although a CVR qualifier is ignored when being applied to a
23794 substituted template parameter ([8.3.2]/1 for example), that
23795 does not allow us to unify "const T" with "int&" because both
23796 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
23797 It is ok when we're allowing additional CV qualifiers
23798 at the outer level [14.8.2.1]/3,1st bullet. */
23807 }
23818 }
23820 /* Determines the LEVEL and INDEX for the template parameter PARM. */
23821 void
23823 {
23827 {
23830 }
23831 else
23832 {
23835 }
23836 }
23838 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
23839 do { \
23840 if (unify (TP, TA, P, A, S, EP)) \
23841 return 1; \
23842 } while (0)
23844 /* Unifies the remaining arguments in PACKED_ARGS with the pack
23845 expansion at the end of PACKED_PARMS. Returns 0 if the type
23846 deduction succeeds, 1 otherwise. STRICT is the same as in
23847 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
23848 function call argument list. We'll need to adjust the arguments to make them
23849 types. SUBR tells us if this is from a recursive call to
23850 type_unification_real, or for comparing two template argument
23851 lists. */
23853 static int
23857 {
23858 tree parm
23864 /* Add in any args remembered from an earlier partial instantiation. */
23872 /* Determine the parameter packs we will be deducing from the
23873 pattern, and record their current deductions. */
23876 {
23880 /* Only template parameter packs can be deduced, not e.g. function
23881 parameter packs or __bases or __integer_pack. */
23885 /* Determine the index and level of this parameter pack. */
23890 /* Keep track of the parameter packs and their corresponding
23891 argument packs. */
23894 }
23896 /* Loop through all of the arguments that have not yet been
23897 unified and unify each with the pattern. */
23899 {
23900 tree parm;
23904 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
23905 or the element of its argument pack at the current index if
23906 this argument was explicitly specified. */
23908 {
23917 {
23920 }
23922 }
23924 /* If we had explicit template arguments, substitute them into the
23925 pattern before deduction. */
23927 {
23928 /* Some arguments might still be unspecified or dependent. */
23936 NULL_TREE);
23941 }
23942 else
23945 /* Unify the pattern with the current argument. */
23947 explain_p))
23950 /* For each parameter pack, collect the deduced value. */
23952 {
23958 }
23959 }
23961 /* Verify that the results of unification with the parameter packs
23962 produce results consistent with what we've seen before, and make
23963 the deduced argument packs available. */
23965 {
23972 /* By default keep the original deduced argument pack.
23973 If necessary, more specific code is going to update the
23974 resulting deduced argument later down in this function. */
23978 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
23979 actually deduce anything. */
23987 {
23988 /* If we had fewer function args than explicit template args,
23989 just use the explicits. */
23994 }
23997 {
23998 tree result;
23999 /* Build the deduced *_ARGUMENT_PACK. */
24001 {
24004 }
24005 else
24010 /* Note the deduced argument packs for this parameter
24011 pack. */
24013 }
24017 {
24018 /* We only had the explicitly-provided arguments before, but
24019 now we have a complete set of arguments. */
24025 }
24026 else
24027 {
24031 /* During template argument deduction for the aggregate deduction
24032 candidate, the number of elements in a trailing parameter pack
24033 is only deduced from the number of remaining function
24034 arguments if it is not otherwise deduced. */
24041 /* Inconsistent unification of this parameter pack. */
24043 bad_old_arg,
24044 bad_new_arg);
24045 }
24046 }
24049 }
24051 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
24052 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
24053 parameters and return value are as for unify. */
24055 static int
24059 {
24060 tree parm_max;
24061 tree arg_max;
24065 /* Our representation of array types uses "N - 1" as the
24066 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
24067 not an integer constant. We cannot unify arbitrarily
24068 complex expressions, so we eliminate the MINUS_EXPRs
24069 here. */
24073 {
24076 }
24080 {
24081 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
24082 trying to unify the type of a variable with the type
24083 of a template parameter. For example:
24085 template <unsigned int N>
24086 void f (char (&) [N]);
24087 int g();
24088 void h(int i) {
24089 char a[g(i)];
24090 f(a);
24091 }
24093 Here, the type of the ARG will be "int [g(i)]", and
24094 may be a SAVE_EXPR, etc. */
24098 }
24100 /* If only one of the bounds used a MINUS_EXPR, compensate
24101 by adding one to the other bound. */
24104 integer_type_node,
24105 parm_max,
24106 integer_one_node);
24109 integer_type_node,
24110 arg_max,
24111 integer_one_node);
24115 }
24117 /* Returns whether T, a P or A in unify, is a type, template or expression. */
24121 static pa_kind_t
24123 {
24132 else
24134 }
24136 /* Deduce the value of template parameters. TPARMS is the (innermost)
24137 set of template parameters to a template. TARGS is the bindings
24138 for those template parameters, as determined thus far; TARGS may
24139 include template arguments for outer levels of template parameters
24140 as well. PARM is a parameter to a template function, or a
24141 subcomponent of that parameter; ARG is the corresponding argument.
24142 This function attempts to match PARM with ARG in a manner
24143 consistent with the existing assignments in TARGS. If more values
24144 are deduced, then TARGS is updated.
24146 Returns 0 if the type deduction succeeds, 1 otherwise. The
24147 parameter STRICT is a bitwise or of the following flags:
24149 UNIFY_ALLOW_NONE:
24150 Require an exact match between PARM and ARG.
24151 UNIFY_ALLOW_MORE_CV_QUAL:
24152 Allow the deduced ARG to be more cv-qualified (by qualification
24153 conversion) than ARG.
24154 UNIFY_ALLOW_LESS_CV_QUAL:
24155 Allow the deduced ARG to be less cv-qualified than ARG.
24156 UNIFY_ALLOW_DERIVED:
24157 Allow the deduced ARG to be a template base class of ARG,
24158 or a pointer to a template base class of the type pointed to by
24159 ARG.
24160 UNIFY_ALLOW_INTEGER:
24161 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
24162 case for more information.
24163 UNIFY_ALLOW_OUTER_LEVEL:
24164 This is the outermost level of a deduction. Used to determine validity
24165 of qualification conversions. A valid qualification conversion must
24166 have const qualified pointers leading up to the inner type which
24167 requires additional CV quals, except at the outer level, where const
24168 is not required [conv.qual]. It would be normal to set this flag in
24169 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
24170 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
24171 This is the outermost level of a deduction, and PARM can be more CV
24172 qualified at this point.
24173 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
24174 This is the outermost level of a deduction, and PARM can be less CV
24175 qualified at this point. */
24177 static int
24180 {
24182 tree targ;
24183 tree tparm;
24185 tsubst_flags_t complain = (explain_p
24186 ? tf_warning_or_error
24189 /* I don't think this will do the right thing with respect to types.
24190 But the only case I've seen it in so far has been array bounds, where
24191 signedness is the only information lost, and I think that will be
24192 okay. VIEW_CONVERT_EXPR can appear with class NTTP, thanks to
24193 finish_id_expression_1, and are also OK. */
24201 /* We can't deduce anything from this, but we might get all the
24202 template args from other function args. */
24208 /* If PARM uses template parameters, then we can't bail out here,
24209 even if ARG == PARM, since we won't record unifications for the
24210 template parameters. We might need them if we're trying to
24211 figure out which of two things is more specialized. */
24215 /* Handle init lists early, so the rest of the function can assume
24216 we're dealing with a type. */
24218 {
24219 tree elttype;
24224 /* We can only deduce from an initializer list argument if the
24225 parameter is std::initializer_list or an array; otherwise this
24226 is a non-deduced context. */
24231 else
24232 {
24234 /* Deduction is defined in terms of a single type, so just punt
24235 on the (bizarre) std::initializer_list<T...>. */
24238 }
24243 /* If ELTTYPE has no deducible template parms, skip deduction from
24245 else
24247 {
24255 {
24259 /* It should only be possible to get here for a call. */
24261 elt_strict |= maybe_adjust_types_for_deduction
24264 }
24267 explain_p);
24268 }
24272 {
24273 /* Also deduce from the length of the initializer list. */
24280 }
24282 /* If the std::initializer_list<T> deduction worked, replace the
24283 deduced A with std::initializer_list<A>. */
24285 {
24290 }
24292 }
24294 /* If parm and arg aren't the same kind of thing (template, type, or
24295 expression), fail early. */
24299 /* Immediately reject some pairs that won't unify because of
24300 cv-qualification mismatches. */
24303 /* It is the elements of the array which hold the cv quals of an array
24304 type, and the elements might be template type parms. We'll check
24305 when we recurse. */
24307 /* We check the cv-qualifiers when unifying with template type
24308 parameters below. We want to allow ARG `const T' to unify with
24309 PARM `T' for example, when computing which of two templates
24310 is more specialized, for example. */
24324 {
24328 /* In a type which contains a nested-name-specifier, template
24329 argument values cannot be deduced for template parameters used
24330 within the nested-name-specifier. */
24342 /* The PARM is not one we're trying to unify. Just check
24343 to see if it matches ARG. */
24344 {
24349 else
24351 }
24358 /* Check for mixed types and values. */
24366 {
24369 {
24370 /* First try to match ARG directly. */
24372 explain_p);
24374 {
24375 /* Otherwise, look for a suitable base of ARG, as below. */
24382 }
24383 }
24384 /* ARG must be constructed from a template class or a template
24385 template parameter. */
24390 /* Deduce arguments T, i from TT<T> or TT<i>. */
24396 /* If the template is a template template parameter, use the
24397 TEMPLATE_TEMPLATE_PARM for matching. */
24400 /* Fall through to deduce template name. */
24401 }
24405 {
24406 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
24408 /* Simple cases: Value already set, does match or doesn't. */
24413 }
24414 else
24415 {
24416 /* If PARM is `const T' and ARG is only `int', we don't have
24417 a match unless we are allowing additional qualification.
24418 If ARG is `const int' and PARM is just `T' that's OK;
24419 that binds `const int' to `T'. */
24424 /* Consider the case where ARG is `const volatile int' and
24425 PARM is `const T'. Then, T should be `volatile int'. */
24426 arg = cp_build_qualified_type
24431 /* Simple cases: Value already set, does match or doesn't. */
24437 /* Make sure that ARG is not a variable-sized array. (Note
24438 that were talking about variable-sized arrays (like
24439 `int[n]'), rather than arrays of unknown size (like
24440 `int[]').) We'll get very confused by such a type since
24441 the bound of the array is not constant, and therefore
24442 not mangleable. Besides, such types are not allowed in
24443 ISO C++, so we can do as we please here. We do allow
24444 them for 'auto' deduction, since that isn't ABI-exposed. */
24448 /* Strip typedefs as in convert_template_argument. */
24450 }
24452 /* If ARG is a parameter pack or an expansion, we cannot unify
24453 against it unless PARM is also a parameter pack. */
24458 /* If the argument deduction results is a METHOD_TYPE,
24459 then there is a problem.
24460 METHOD_TYPE doesn't map to any real C++ type the result of
24461 the deduction cannot be of that type. */
24475 {
24476 /* The PARM is not one we're trying to unify. Just check
24477 to see if it matches ARG. */
24483 }
24489 {
24493 /* We're deducing from an array bound, the type doesn't matter. */
24499 }
24501 /* [temp.deduct.type] If, in the declaration of a function template
24502 with a non-type template-parameter, the non-type
24503 template-parameter is used in an expression in the function
24504 parameter-list and, if the corresponding template-argument is
24505 deduced, the template-argument type shall match the type of the
24506 template-parameter exactly, except that a template-argument
24507 deduced from an array bound may be of any integral type.
24508 The non-type parameter might use already deduced type parameters. */
24511 /* We don't have enough levels of args to do any substitution. This
24513 else
24514 {
24520 {
24525 }
24526 }
24530 /* Template-parameter dependent expression. Just accept it for now.
24531 It will later be processed in convert_template_argument. */
24532 ;
24536 /* OK. Ignore top-level quals here because a class-type template
24540 /* Convert the ARG to the type of PARM; the deduced non-type
24541 template argument must exactly match the types of the
24542 corresponding parameter. */
24545 {
24546 /* We haven't deduced the type of this parameter yet. */
24548 /* We deduce from array bounds in try_array_deduction. */
24551 {
24552 /* Deduce it from the non-type argument. As above, ignore
24553 top-level quals here too. */
24558 /* Now check whether the type of this parameter is still
24559 dependent, and give up if so. */
24565 }
24566 else
24567 /* Try again later. */
24569 }
24570 else
24573 /* If ARG is a parameter pack or an expansion, we cannot unify
24574 against it unless PARM is also a parameter pack. */
24579 {
24582 }
24587 {
24588 /* A pointer-to-member constant can be unified only with
24589 another constant. */
24593 /* Just unify the class member. It would be useless (and possibly
24594 wrong, depending on the strict flags) to unify also
24595 PTRMEM_CST_CLASS, because we want to be sure that both parm and
24596 arg refer to the same variable, even if through different
24597 classes. For instance:
24599 struct A { int x; };
24600 struct B : A { };
24602 Unification of &A::x and &B::x must succeed. */
24605 }
24608 {
24612 /* [temp.deduct.call]
24614 A can be another pointer or pointer to member type that can
24615 be converted to the deduced A via a qualification
24616 conversion (_conv.qual_).
24618 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
24619 This will allow for additional cv-qualification of the
24620 pointed-to types if appropriate. */
24623 /* The derived-to-base conversion only persists through one
24624 level of pointers. */
24629 }
24662 /* We have already checked cv-qualification at the top of the
24663 function. */
24667 /* As far as unification is concerned, this wins. Later checks
24668 will invalidate it if necessary. */
24671 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
24672 /* Type INTEGER_CST can come from ordinary constant template args. */
24684 {
24694 /* Check for pack expansions in the parameters. */
24696 {
24698 {
24700 /* We can unify against something with a trailing
24701 parameter pack. */
24703 else
24704 /* [temp.deduct.type]/9: If the template argument list of
24705 P contains a pack expansion that is not the last
24706 template argument, the entire template argument list
24707 is a non-deduced context. */
24709 }
24710 }
24712 /* If we don't have enough arguments to satisfy the parameters
24713 (not counting the pack expression at the end), or we have
24714 too many arguments for a parameter list that doesn't end in
24715 a pack expression, we can't unify. */
24721 /* Unify all of the parameters that precede the (optional)
24722 pack expression. */
24724 {
24729 }
24732 DEDUCE_EXACT,
24735 }
24743 {
24751 }
24756 {
24760 {
24761 /* First, we try to unify the PARM and ARG directly. */
24766 {
24767 /* Fallback to the special case allowed in
24768 [temp.deduct.call]:
24770 If P is a class, and P has the form
24771 template-id, then A can be a derived class of
24772 the deduced A. Likewise, if P is a pointer to
24773 a class of the form template-id, A can be a
24774 pointer to a derived class pointed to by the
24775 deduced A. */
24781 {
24782 /* Don't give the derived diagnostic if we're
24783 already dealing with the same template. */
24784 bool same_template
24790 }
24791 }
24792 }
24796 /* Perhaps PARM is something like S<U> and ARG is S<int>.
24797 Then, we should unify `int' and `U'. */
24799 else
24800 /* There's no chance of unification succeeding. */
24805 }
24812 {
24815 tree a;
24821 /* CV qualifications for methods can never be deduced, they must
24822 match exactly. We need to check them explicitly here,
24823 because type_unification_real treats them as any other
24824 cv-qualified parameter. */
24826 && (!check_cv_quals_for_unify
24854 {
24866 }
24869 }
24872 /* Unify a pointer to member with a pointer to member function, which
24873 deduces the type of the member as a function type. */
24875 {
24876 /* Check top-level cv qualifiers */
24884 /* Determine the type of the function we are unifying against. */
24888 }
24907 /* Matched cases are handled by the ARG == PARM test above. */
24911 /* We might get a variable as a non-type template argument in parm if the
24912 corresponding parameter is type-dependent. Make any necessary
24913 adjustments based on whether arg is a reference. */
24917 {
24922 }
24923 /* Now use the normal expression code to check whether they match. */
24934 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
24935 or UNDERLYING_TYPE nodes. */
24939 /* Unification fails if we hit an error node. */
24944 {
24954 }
24955 /* FALLTHRU */
24958 /* An unresolved overload is a nondeduced context. */
24964 expr:
24965 /* We must be looking at an expression. This can happen with
24966 something like:
24968 template <int I>
24969 void foo(S<I>, S<I + 2>);
24971 or
24973 template<typename T>
24974 void foo(A<T, T{}>);
24976 This is a "non-deduced context":
24978 [deduct.type]
24980 The non-deduced contexts are:
24982 --A non-type template argument or an array bound in which
24983 a subexpression references a template parameter.
24985 In these cases, we assume deduction succeeded, but don't
24986 actually infer any unifications. */
24991 else
24993 }
24994 }
24995 #undef RECUR_AND_CHECK_FAILURE
24996 \f
24997 /* Note that DECL can be defined in this translation unit, if
24998 required. */
25000 static void
25002 {
25003 tree clone;
25007 }
25009 /* Called if RESULT is explicitly instantiated, or is a member of an
25010 explicitly instantiated class. */
25012 void
25014 {
25017 /* If this entity has already been written out, it's too late to
25018 make any modifications. */
25022 /* consteval functions are never emitted. */
25027 /* For anonymous namespace we don't need to do anything. */
25029 {
25032 }
25035 /* The TREE_PUBLIC flag for function declarations will have been
25036 set correctly by tsubst. */
25040 {
25043 }
25044 else
25045 {
25048 /* Always make artificials weak. */
25051 /* For WIN32 we also want to put explicit instantiations in
25052 linkonce sections. */
25057 /* If the function has already been instantiated, clear DECL_EXTERNAL,
25058 since start_preparsed_function wouldn't have if we had an earlier
25059 extern explicit instantiation. */
25061 }
25063 /* If EXTERN_P, then this function will not be emitted -- unless
25064 followed by an explicit instantiation, at which point its linkage
25065 will be adjusted. If !EXTERN_P, then this function will be
25066 emitted here. In neither circumstance do we want
25067 import_export_decl to adjust the linkage. */
25069 }
25071 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
25072 important template arguments. If any are missing, we check whether
25073 they're important by using error_mark_node for substituting into any
25074 args that were used for partial ordering (the ones between ARGS and END)
25075 and seeing if it bubbles up. */
25077 static bool
25079 {
25083 {
25086 }
25088 {
25092 }
25094 }
25096 /* Given two function templates PAT1 and PAT2, return:
25098 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
25099 -1 if PAT2 is more specialized than PAT1.
25100 0 if neither is more specialized.
25102 LEN indicates the number of parameters we should consider
25103 (defaulted parameters should not be considered).
25105 The 1998 std underspecified function template partial ordering, and
25106 DR214 addresses the issue. We take pairs of arguments, one from
25107 each of the templates, and deduce them against each other. One of
25108 the templates will be more specialized if all the *other*
25109 template's arguments deduce against its arguments and at least one
25110 of its arguments *does* *not* deduce against the other template's
25111 corresponding argument. Deduction is done as for class templates.
25112 The arguments used in deduction have reference and top level cv
25113 qualifiers removed. Iff both arguments were originally reference
25114 types *and* deduction succeeds in both directions, an lvalue reference
25115 wins against an rvalue reference and otherwise the template
25116 with the more cv-qualified argument wins for that pairing (if
25117 neither is more cv-qualified, they both are equal). Unlike regular
25118 deduction, after all the arguments have been deduced in this way,
25119 we do *not* verify the deduced template argument values can be
25120 substituted into non-deduced contexts.
25122 The logic can be a bit confusing here, because we look at deduce1 and
25123 targs1 to see if pat2 is at least as specialized, and vice versa; if we
25124 can find template arguments for pat1 to make arg1 look like arg2, that
25125 means that arg2 is at least as specialized as arg1. */
25127 int
25129 {
25142 /* Remove the this parameter from non-static member functions. If
25143 one is a non-static member function and the other is not a static
25144 member function, remove the first parameter from that function
25145 also. This situation occurs for operator functions where we
25146 locate both a member function (with this pointer) and non-member
25147 operator (with explicit first operand). */
25149 {
25154 }
25156 {
25159 {
25160 len--;
25162 }
25163 }
25165 /* If only one is a conversion operator, they are unordered. */
25169 /* Consider the return type for a conversion function */
25171 {
25174 len++;
25175 }
25177 processing_template_decl++;
25183 /* Stop when an ellipsis is seen. */
25185 {
25196 {
25197 /* When both arguments are pack expansions, we need only
25198 unify the patterns themselves. */
25202 /* This is the last comparison we need to do. */
25204 }
25207 {
25211 }
25214 {
25218 }
25224 {
25230 /* Setup the parameter vector, which contains only ARG1. */
25233 /* Setup the argument vector, which contains the remaining
25234 arguments. */
25243 /* We cannot deduce in the other direction, because ARG1 is
25244 a pack expansion but ARG2 is not. */
25246 }
25248 {
25254 /* Setup the parameter vector, which contains only ARG1. */
25257 /* Setup the argument vector, which contains the remaining
25258 arguments. */
25267 /* We cannot deduce in the other direction, because ARG2 is
25268 a pack expansion but ARG1 is not.*/
25270 }
25272 else
25273 {
25274 /* The normal case, where neither argument is a pack
25275 expansion. */
25282 }
25284 /* If we couldn't deduce arguments for tparms1 to make arg1 match
25285 arg2, then arg2 is not as specialized as arg1. */
25291 /* "If, for a given type, deduction succeeds in both directions
25292 (i.e., the types are identical after the transformations above)
25293 and both P and A were reference types (before being replaced with
25294 the type referred to above):
25295 - if the type from the argument template was an lvalue reference and
25296 the type from the parameter template was not, the argument type is
25297 considered to be more specialized than the other; otherwise,
25298 - if the type from the argument template is more cv-qualified
25299 than the type from the parameter template (as described above),
25300 the argument type is considered to be more specialized than the other;
25301 otherwise,
25302 - neither type is more specialized than the other." */
25305 {
25307 {
25310 else
25312 }
25314 {
25319 }
25320 }
25323 /* We've failed to deduce something in either direction.
25324 These must be unordered. */
25329 /* We have already processed all of the arguments in our
25330 handing of the pack expansion type. */
25335 }
25337 /* "In most cases, all template parameters must have values in order for
25338 deduction to succeed, but for partial ordering purposes a template
25339 parameter may remain without a value provided it is not used in the
25340 types being used for partial ordering."
25342 Thus, if we are missing any of the targs1 we need to substitute into
25343 origs1, then pat2 is not as specialized as pat1. This can happen when
25344 there is a nondeduced context. */
25350 processing_template_decl--;
25352 /* If both deductions succeed, the partial ordering selects the more
25353 constrained template. */
25354 /* P2113: If the corresponding template-parameters of the
25355 template-parameter-lists are not equivalent ([temp.over.link]) or if
25356 the function parameters that positionally correspond between the two
25357 templates are not of the same type, neither template is more
25358 specialized than the other. */
25363 {
25369 }
25371 /* All things being equal, if the next argument is a pack expansion
25372 for one function but not for the other, prefer the
25373 non-variadic function. FIXME this is bogus; see c++/41958. */
25377 {
25380 }
25386 else
25388 }
25390 /* Determine which of two partial specializations of TMPL is more
25391 specialized.
25393 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
25394 to the first partial specialization. The TREE_PURPOSE is the
25395 innermost set of template parameters for the partial
25396 specialization. PAT2 is similar, but for the second template.
25398 Return 1 if the first partial specialization is more specialized;
25399 -1 if the second is more specialized; 0 if neither is more
25400 specialized.
25402 See [temp.class.order] for information about determining which of
25403 two templates is more specialized. */
25405 static int
25407 {
25408 tree targs;
25417 /* Just like what happens for functions, if we are ordering between
25418 different template specializations, we may encounter dependent
25419 types in the arguments, and we need our dependency check functions
25420 to behave correctly. */
25424 {
25427 }
25431 {
25434 }
25437 /* If both deductions succeed, the partial ordering selects the more
25438 constrained template. */
25442 /* In the case of a tie where at least one of the templates
25443 has a parameter pack at the end, the template with the most
25444 non-packed parameters wins. */
25446 && any_deductions
25449 {
25455 /* We don't count the pack expansion at the end. */
25465 }
25468 }
25470 /* Return the template arguments that will produce the function signature
25471 DECL from the function template FN, with the explicit template
25472 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
25473 also match. Return NULL_TREE if no satisfactory arguments could be
25474 found. */
25476 static tree
25478 {
25482 tree decl_arg_types;
25485 tree arg;
25489 /* Never do unification on the 'this' parameter. */
25511 }
25513 /* Return the innermost template arguments that, when applied to a partial
25514 specialization SPEC_TMPL of TMPL, yield the ARGS.
25516 For example, suppose we have:
25518 template <class T, class U> struct S {};
25519 template <class T> struct S<T*, int> {};
25521 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
25522 partial specialization and the ARGS will be {double*, int}. The resulting
25523 vector will be {double}, indicating that `T' is bound to `double'. */
25525 static tree
25527 {
25529 tree spec_args
25532 tree deduced_args;
25533 tree innermost_deduced_args;
25537 {
25541 innermost_deduced_args);
25542 }
25543 else
25547 again:
25556 {
25558 {
25564 }
25566 }
25569 {
25572 }
25574 /* Verify that nondeduced template arguments agree with the type
25575 obtained from argument deduction.
25577 For example:
25579 struct A { typedef int X; };
25580 template <class T, class U> struct C {};
25581 template <class T> struct C<T, typename T::X> {};
25583 Then with the instantiation `C<A, int>', we can deduce that
25584 `T' is `A' but unify () does not check whether `typename T::X'
25585 is `int'. */
25596 /* We only need to check the innermost arguments; the other
25597 arguments will always agree. */
25602 /* Now that we have bindings for all of the template arguments,
25603 ensure that the arguments deduced for the template template
25604 parameters have compatible template parameter lists. See the use
25605 of template_template_parm_bindings_ok_p in fn_type_unification
25606 for more information. */
25611 }
25613 // Compare two function templates T1 and T2 by deducing bindings
25614 // from one against the other. If both deductions succeed, compare
25615 // constraints to see which is more constrained.
25616 static int
25618 {
25623 {
25626 }
25629 {
25632 }
25634 // If both deductions succeed, then one may be more constrained.
25639 }
25641 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
25642 Return the TREE_LIST node with the most specialized template, if
25643 any. If there is no most specialized template, the error_mark_node
25644 is returned.
25646 Note that this function does not look at, or modify, the
25647 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
25648 returned is one of the elements of INSTANTIATIONS, callers may
25649 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
25650 and retrieve it from the value returned. */
25652 tree
25654 {
25661 {
25667 {
25668 /* Equally specialized, move to next function. If there
25669 is no next function, nothing's most specialized. */
25674 }
25675 }
25678 /* Now verify that champ is better than everything earlier in the
25679 instantiation list. */
25682 {
25685 }
25686 }
25688 processing_template_decl--;
25694 }
25696 /* If DECL is a specialization of some template, return the most
25697 general such template. Otherwise, returns NULL_TREE.
25699 For example, given:
25701 template <class T> struct S { template <class U> void f(U); };
25703 if TMPL is `template <class U> void S<int>::f(U)' this will return
25704 the full template. This function will not trace past partial
25705 specializations, however. For example, given in addition:
25707 template <class T> struct S<T*> { template <class U> void f(U); };
25709 if TMPL is `template <class U> void S<int*>::f(U)' this will return
25710 `template <class T> template <class U> S<T*>::f(U)'. */
25712 tree
25714 {
25716 {
25719 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
25720 template friend, or a FIELD_DECL for a capture pack. */
25723 }
25725 /* Look for more and more general templates. */
25727 {
25728 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
25729 (See cp-tree.h for details.) */
25738 /* Stop if we run into an explicitly specialized class template. */
25745 }
25748 }
25750 /* Return the most specialized of the template partial specializations
25751 which can produce TARGET, a specialization of some class or variable
25752 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
25753 a TEMPLATE_DECL node corresponding to the partial specialization, while
25754 the TREE_PURPOSE is the set of template arguments that must be
25755 substituted into the template pattern in order to generate TARGET.
25757 If the choice of partial specialization is ambiguous, a diagnostic
25758 is issued, and the error_mark_node is returned. If there are no
25759 partial specializations matching TARGET, then NULL_TREE is
25760 returned, indicating that the primary template should be used. */
25762 tree
25764 {
25766 tree t;
25767 tree champ;
25773 tree decl;
25775 {
25780 }
25782 {
25786 }
25788 {
25793 }
25794 else
25802 /* For determining which partial specialization to use, only the
25803 innermost args are interesting. */
25805 {
25808 }
25810 /* The caller hasn't called push_to_top_level yet, but we need
25811 get_partial_spec_bindings to be done in non-template context so that we'll
25812 fully resolve everything. */
25813 processing_template_decl_sentinel ptds;
25816 {
25819 tree spec_tmpl;
25821 {
25822 /* Substitute in the template args from the enclosing class. */
25828 }
25829 else
25834 {
25838 /* Keep the candidate only if the constraints are satisfied,
25839 or if we're not compiling with concepts. */
25842 {
25845 }
25846 }
25847 }
25857 {
25860 ;
25861 else
25862 {
25864 {
25867 {
25870 }
25871 }
25873 }
25874 }
25878 {
25881 {
25884 }
25885 }
25888 {
25895 else
25899 {
25904 }
25907 }
25910 }
25912 /* Explicitly instantiate DECL. */
25914 void
25916 {
25921 /* An error occurred, for which grokdeclarator has already issued
25922 an appropriate message. */
25925 {
25928 }
25930 {
25933 else
25936 }
25942 {
25943 /* There is an asymmetry here in the way VAR_DECLs and
25944 FUNCTION_DECLs are handled by grokdeclarator. In the case of
25945 the latter, the DECL we get back will be marked as a
25946 template instantiation, and the appropriate
25947 DECL_TEMPLATE_INFO will be set up. This does not happen for
25948 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
25949 should handle VAR_DECLs as it currently handles
25950 FUNCTION_DECLs. */
25952 {
25955 }
25958 {
25961 }
25963 {
25968 }
25969 }
25971 {
25974 }
25975 else
25978 /* Check for various error cases. Note that if the explicit
25979 instantiation is valid the RESULT will currently be marked as an
25980 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
25981 until we get here. */
25984 {
25985 /* DR 259 [temp.spec].
25987 Both an explicit instantiation and a declaration of an explicit
25988 specialization shall not appear in a program unless the explicit
25989 instantiation follows a declaration of the explicit specialization.
25991 For a given set of template parameters, if an explicit
25992 instantiation of a template appears after a declaration of an
25993 explicit specialization for that template, the explicit
25994 instantiation has no effect. */
25996 }
25998 {
25999 /* [temp.spec]
26001 No program shall explicitly instantiate any template more
26002 than once.
26004 We check DECL_NOT_REALLY_EXTERN so as not to complain when
26005 the first instantiation was `extern' and the second is not,
26006 and EXTERN_P for the opposite case. */
26009 /* If an "extern" explicit instantiation follows an ordinary
26010 explicit instantiation, the template is instantiated. */
26013 }
26015 {
26018 }
26020 {
26023 }
26026 ;
26028 {
26031 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
26034 }
26035 else
26043 }
26045 static void
26047 {
26053 {
26056 }
26057 }
26059 /* Perform an explicit instantiation of template class T. STORAGE, if
26060 non-null, is the RID for extern, inline or static. COMPLAIN is
26061 nonzero if this is called from the parser, zero if called recursively,
26062 since the standard is unclear (as detailed below). */
26064 void
26066 {
26068 {
26072 else
26075 }
26080 {
26083 t);
26085 }
26087 /* At most one of these will be true. */
26093 {
26095 {
26098 "ISO C++ 1998 forbids the use of %<extern%> on "
26100 }
26101 else
26103 "ISO C++ forbids the use of %qE"
26112 else
26114 storage);
26115 }
26118 /* DR 259 [temp.spec].
26120 Both an explicit instantiation and a declaration of an explicit
26121 specialization shall not appear in a program unless the
26122 explicit instantiation follows a declaration of the explicit
26123 specialization.
26125 For a given set of template parameters, if an explicit
26126 instantiation of a template appears after a declaration of an
26127 explicit specialization for that template, the explicit
26128 instantiation has no effect. */
26132 {
26133 /* We've already instantiated the template. */
26135 /* [temp.spec]
26137 No program shall explicitly instantiate any template more
26138 than once.
26140 If EXTERN_P then this is ok. */
26146 }
26154 /* In contrast to implicit instantiation, where only the
26155 declarations, and not the definitions, of members are
26156 instantiated, we have here:
26158 [temp.explicit]
26160 An explicit instantiation that names a class template
26161 specialization is also an explicit instantiation of the same
26162 kind (declaration or definition) of each of its members (not
26163 including members inherited from base classes and members
26164 that are templates) that has not been previously explicitly
26165 specialized in the translation unit containing the explicit
26166 instantiation, provided that the associated constraints, if
26167 any, of that member are satisfied by the template arguments
26168 of the explicit instantiation. */
26172 && !static_p
26176 {
26181 }
26183 {
26189 }
26190 }
26192 /* Given a function DECL, which is a specialization of TMPL, modify
26193 DECL to be a re-instantiation of TMPL with the same template
26194 arguments. TMPL should be the template into which tsubst'ing
26195 should occur for DECL, not the most general template.
26197 One reason for doing this is a scenario like this:
26199 template <class T>
26200 void f(const T&, int i);
26202 void g() { f(3, 7); }
26204 template <class T>
26205 void f(const T& t, const int i) { }
26207 Note that when the template is first instantiated, with
26208 instantiate_template, the resulting DECL will have no name for the
26209 first parameter, and the wrong type for the second. So, when we go
26210 to instantiate the DECL, we regenerate it. */
26212 static void
26214 {
26215 /* The arguments used to instantiate DECL, from the most general
26216 template. */
26217 tree code_pattern;
26221 /* Make sure that we can see identifiers, and compute access
26222 correctly. */
26226 {
26227 tree specs;
26231 /* Use the source location of the definition. */
26239 /* Instantiate a dynamic exception-specification. noexcept will be
26240 handled below. */
26243 {
26249 specs);
26250 }
26252 /* Merge parameter declarations. */
26256 {
26263 }
26265 /* Merge additional specifiers from the CODE_PATTERN. */
26271 }
26273 {
26282 }
26283 else
26287 }
26289 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
26290 substituted to get DECL. */
26292 tree
26294 {
26297 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
26298 for the instantiation. This is not always the most general
26299 template. Consider, for example:
26301 template <class T>
26302 struct S { template <class U> void f();
26303 template <> void f<int>(); };
26305 and an instantiation of S<double>::f<int>. We want TD to be the
26306 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
26308 more general template. */
26310 /* We must also deal with friend templates. Given:
26312 template <class T> struct S {
26313 template <class U> friend void f() {};
26314 };
26316 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
26317 so far as the language is concerned, but that's still
26318 where we get the pattern for the instantiation from. On
26319 other hand, if the definition comes outside the class, say:
26321 template <class T> struct S {
26322 template <class U> friend void f();
26323 };
26324 template <class U> friend void f() {}
26326 we don't need to look any further. That's what the check for
26327 DECL_INITIAL is for. */
26331 {
26332 /* The present template, TD, should not be a definition. If it
26333 were a definition, we should be using it! Note that we
26334 cannot restructure the loop to just keep going until we find
26335 a template with a definition, since that might go too far if
26336 a specialization was declared, but not defined. */
26338 /* Fetch the more general template. */
26340 }
26343 }
26345 /* Returns true if we need to instantiate this template instance even if we
26346 know we aren't going to emit it. */
26348 bool
26350 {
26351 /* We always instantiate inline functions so that we can inline them. An
26352 explicit instantiation declaration prohibits implicit instantiation of
26353 non-inline functions. With high levels of optimization, we would
26354 normally inline non-inline functions -- but we're not allowed to do
26355 that for "extern template" functions. Therefore, we check
26356 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
26360 /* And we need to instantiate static data members so that
26361 their initializers are available in integral constant
26362 expressions. */
26365 }
26367 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
26368 instantiate it now, modifying TREE_TYPE (fn). Returns false on
26369 error, true otherwise. */
26371 bool
26373 {
26377 /* Don't instantiate a noexcept-specification from template context. */
26387 {
26389 /* We're in start_preparsed_function, keep going. */
26396 }
26407 /* For a member friend template we can get a TEMPLATE_DECL. Let's use
26408 its FUNCTION_DECL for the rest of this function -- push_access_scope
26409 doesn't accept TEMPLATE_DECLs. */
26411 {
26414 }
26417 {
26422 }
26424 {
26428 {
26431 /* This might have failed because of an unparsed DMI, so
26432 let's try again later. */
26434 }
26436 {
26437 /* If hash_set::add returns true, the element was already there. */
26442 fn);
26444 }
26446 {
26454 {
26455 /* If needed, set current_class_ptr for the benefit of
26456 tsubst_copy/PARM_DECL. */
26461 }
26463 /* If this function is represented by a TEMPLATE_DECL, then
26464 the deferred noexcept-specification might still contain
26465 dependent types, even after substitution. And we need the
26466 dependency check functions to work in build_noexcept_spec. */
26470 /* Do deferred instantiation of the noexcept-specifier. */
26477 /* Build up the noexcept-specification. */
26487 }
26488 else
26493 }
26496 {
26497 /* This failed with a hard error, so let's go with false. */
26500 }
26507 }
26509 /* We're starting to process the function INST, an instantiation of PATTERN;
26510 add their parameters to local_specializations. */
26512 static void
26514 {
26518 {
26522 }
26524 {
26526 {
26529 }
26530 else
26531 {
26532 /* Register the (value) argument pack as a specialization of
26533 TMPL_PARM, then move on. */
26536 }
26537 }
26539 }
26541 /* Instantiate the body of D using PATTERN with ARGS. We have
26542 already determined PATTERN is the correct template to use.
26543 NESTED_P is true if this is a nested function, in which case
26544 PATTERN will be a FUNCTION_DECL not a TEMPLATE_DECL. */
26546 static void
26548 {
26553 {
26556 }
26557 else
26558 /* Only OMP reductions are nested. */
26565 bool push_to_top
26566 = !(current_function_decl
26572 else
26573 {
26578 }
26581 {
26582 /* The variable might be a lambda's extra scope, and that
26583 lambda's visibility depends on D's. */
26586 }
26588 /* Mark D as instantiated so that recursive calls to
26589 instantiate_decl do not try to instantiate it again. */
26593 /* Regenerate the declaration in case the template has been modified
26594 by a subsequent redeclaration. */
26597 /* We already set the file and line above. Reset them now in case
26598 they changed as a result of calling regenerate_decl_from_template. */
26602 {
26603 /* Clear out DECL_RTL; whatever was there before may not be right
26604 since we've reset the type of the declaration. */
26608 /* The initializer is placed in DECL_INITIAL by
26609 regenerate_decl_from_template so we don't need to
26610 push/pop_access_scope again here. Pull it out so that
26611 cp_finish_decl can process it. */
26617 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
26618 initializer. That function will defer actual emission until
26619 we have a chance to determine linkage. */
26622 /* Enter the scope of D so that access-checking works correctly. */
26632 }
26636 {
26637 /* Set up the list of local specializations. */
26641 /* Set up context. */
26644 else
26645 {
26649 }
26651 /* Create substitution entries for the parameters. */
26654 /* Substitute into the body of the function. */
26658 else
26659 {
26664 /* Set the current input_location to the end of the function
26665 so that finish_function knows where we are. */
26666 input_location
26669 /* Remember if we saw an infinite loop in the template. */
26670 current_function_infinite_loop
26672 }
26674 /* Finish the function. */
26677 else
26678 {
26681 }
26685 }
26687 /* We're not deferring instantiation any more. */
26693 else
26698 }
26700 /* Produce the definition of D, a _DECL generated from a template. If
26701 DEFER_OK is true, then we don't have to actually do the
26702 instantiation now; we just have to do it sometime. Normally it is
26703 an error if this is an explicit instantiation but D is undefined.
26704 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
26705 instantiated class template. */
26707 tree
26709 {
26711 tree gen_args;
26712 tree args;
26713 tree td;
26714 tree code_pattern;
26715 tree spec;
26716 tree gen_tmpl;
26724 /* This function should only be used to instantiate templates for
26725 functions and static member variables. */
26728 /* A concept is never instantiated. */
26734 /* We may have a pending instantiation of D itself. */
26737 /* Variables are never deferred; if instantiation is required, they
26738 are instantiated right away. That allows for better code in the
26739 case that an expression refers to the value of the variable --
26740 if the variable has a constant value the referring expression can
26741 take advantage of that fact. */
26745 /* Don't instantiate cloned functions. Instead, instantiate the
26746 functions they cloned. */
26755 /* D has already been instantiated or explicitly specialized, so
26756 there's nothing for us to do here.
26758 It might seem reasonable to check whether or not D is an explicit
26759 instantiation, and, if so, stop here. But when an explicit
26760 instantiation is deferred until the end of the compilation,
26761 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
26762 the instantiation. */
26765 /* Check to see whether we know that this template will be
26766 instantiated in some other file, as with "extern template"
26767 extension. */
26770 /* In general, we do not instantiate such templates. */
26777 /* We should already have the extra args. */
26781 /* And what's in the hash table should match D. */
26783 == d
26786 /* This needs to happen before any tsubsting. */
26792 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
26793 for the instantiation. */
26798 {
26799 /* Look up an explicit specialization, if any. */
26802 {
26805 }
26806 }
26810 /* We should never be trying to instantiate a member of a class
26811 template or partial specialization. */
26816 /* In the case of a friend template whose definition is provided
26817 outside the class, we may have too many arguments. Drop the
26818 ones we don't need. The same is true for specializations. */
26819 args = get_innermost_template_args
26823 {
26829 }
26830 else
26831 {
26835 else
26837 }
26839 /* We may be in the middle of deferred access check. Disable it now. */
26842 /* Unless an explicit instantiation directive has already determined
26843 the linkage of D, remember that a definition is available for
26844 this entity. */
26854 /* If D is a member of an explicitly instantiated class template,
26855 and no definition is available, treat it like an implicit
26856 instantiation. */
26859 {
26860 /* Leave linkage flags alone on instantiations with anonymous
26861 visibility. */
26863 {
26866 }
26868 }
26870 /* Defer all other templates, unless we have been explicitly
26871 forbidden from doing so. */
26873 template. */
26874 ! pattern_defined
26875 /* If it's OK to postpone instantiation, do so. */
26876 || defer_ok
26877 /* If this is a static data member that will be defined
26878 elsewhere, we don't want to instantiate the entire data
26879 member, but we do want to instantiate the initializer so that
26880 we can substitute that elsewhere. */
26882 /* Handle here a deleted function too, avoid generating
26883 its body (c++/61080). */
26885 {
26886 /* The definition of the static data member is now required so
26887 we must substitute the initializer. */
26891 {
26892 tree ns;
26893 tree init;
26902 args,
26905 /* If instantiating the initializer involved instantiating this
26906 again, don't call cp_finish_decl twice. */
26908 {
26909 /* Make sure the initializer is still constant, in case of
26910 circular dependency (template/instantiate6.C). */
26911 const_init
26915 }
26919 }
26921 /* We restore the source position here because it's used by
26922 add_pending_template. */
26928 /* [temp.explicit]
26930 The definition of a non-exported function template, a
26931 non-exported member function template, or a non-exported
26932 member function or static data member of a class template
26933 shall be present in every translation unit in which it is
26934 explicitly instantiated. */
26938 /* If we're in unevaluated context, we just wanted to get the
26939 constant value; this isn't an odr use, so don't queue
26940 a full instantiation. */
26942 /* ??? Historically, we have instantiated inline functions, even
26943 when marked as "extern template". */
26946 }
26947 else
26948 {
26953 }
26962 }
26964 /* Run through the list of templates that we wish we could
26965 instantiate, and instantiate any we can. RETRIES is the
26966 number of times we retry pending template instantiation. */
26968 void
26970 {
26974 /* Instantiating templates may trigger vtable generation. This in turn
26975 may require further template instantiations. We place a limit here
26976 to avoid infinite loop. */
26978 {
26982 "template instantiation depth exceeds maximum of %d"
26983 " instantiating %q+D, possibly from virtual table generation"
26987 /* Pretend that we defined it. */
26990 }
26992 do
26993 {
26998 {
27003 {
27005 {
27020 }
27023 }
27024 else
27025 {
27028 {
27029 instantiation
27035 }
27039 }
27042 {
27043 /* If INSTANTIATION has been instantiated, then we don't
27044 need to consider it again in the future. */
27049 }
27050 else
27051 {
27054 }
27057 }
27059 }
27063 }
27065 /* Substitute ARGVEC into T, which is a list of initializers for
27066 either base class or a non-static data member. The TREE_PURPOSEs
27067 are DECLs, and the TREE_VALUEs are the initializer values. Used by
27068 instantiate_decl. */
27070 static tree
27072 {
27077 {
27078 tree decl;
27079 tree init;
27085 {
27086 tree expr;
27087 tree arg;
27089 /* Expand the base class expansion type into separate base
27090 classes. */
27092 tf_warning_or_error,
27093 NULL_TREE);
27097 /* We'll be building separate TREE_LISTs of arguments for
27098 each base. */
27104 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
27105 expand each argument in the TREE_VALUE of t. */
27112 /* VOID_TYPE_NODE is used to indicate
27113 value-initialization. */
27114 {
27117 }
27118 else
27119 {
27120 /* Substitute parameter packs into each argument in the
27121 TREE_LIST. */
27124 {
27125 tree expanded_exprs;
27127 /* Expand the argument. */
27128 tree value;
27131 else
27132 {
27135 }
27136 expanded_exprs
27138 tf_warning_or_error,
27139 NULL_TREE);
27143 /* Prepend each of the expanded expressions to the
27144 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
27152 else
27157 }
27160 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
27161 since we built them backwards. */
27163 {
27166 }
27167 }
27168 }
27171 {
27173 {
27177 }
27178 else
27179 {
27180 tree tmp;
27195 /* If we had an initializer but it instantiated to nothing,
27196 value-initialize the object. This will only occur when
27197 the initializer was a pack expansion where the parameter
27198 packs used in that expansion were of length zero. */
27201 }
27205 {
27207 decl);
27209 }
27210 /* Look for a target constructor. */
27214 {
27217 {
27221 }
27223 }
27226 {
27228 /* Carry over the dummy TREE_TYPE node containing the source
27229 location. */
27233 }
27234 }
27235 }
27237 }
27239 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
27240 is the instantiation (which should have been created with
27241 start_enum) and ARGS are the template arguments to use. */
27243 static void
27245 {
27246 tree e;
27252 {
27253 tree value;
27256 /* Note that in a template enum, the TREE_VALUE is the
27257 CONST_DECL, not the corresponding INTEGER_CST. */
27262 /* Give this enumeration constant the correct access. */
27265 /* Actually build the enumerator itself. Here we're assuming that
27266 enumerators can't have dependent attributes. */
27270 /* Attribute deprecated without an argument isn't sticky: it'll
27271 melt into a tree flag, so we need to propagate the flag here,
27272 since we just created a new enumerator. */
27275 }
27287 }
27289 /* DECL is a FUNCTION_DECL that is a template specialization. Return
27290 its type -- but without substituting the innermost set of template
27291 arguments. So, innermost set of template parameters will appear in
27292 the type. */
27294 tree
27296 {
27297 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
27299 }
27301 /* Return truthvalue if we're processing a template different from
27302 the last one involved in diagnostics. */
27303 bool
27305 {
27307 }
27309 /* Remember current template involved in diagnostics. */
27310 void
27312 {
27314 }
27318 {
27320 }
27322 /* Return TRUE if current_function_decl is being instantiated, false
27323 otherwise. */
27325 bool
27327 {
27331 }
27333 /* [temp.param] Check that template non-type parm TYPE is of an allowable
27334 type. Return false for ok, true for disallowed. Issue error and
27335 inform messages under control of COMPLAIN. */
27337 static bool
27339 {
27350 {
27352 {
27357 }
27359 }
27364 /* Fall through; before C++11 alias templates, a bound ttp
27367 /* Any other wildcard type not already handled above is allowed. */
27374 {
27382 {
27383 auto_diagnostic_group d;
27387 }
27389 }
27391 {
27396 }
27399 {
27402 else
27404 type);
27405 }
27407 }
27409 /* Returns true iff the noexcept-specifier for TYPE is value-dependent. */
27411 static bool
27413 {
27416 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
27417 affect overload resolution and treating it as dependent breaks
27418 things. Same for an unparsed noexcept expression. */
27425 }
27427 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
27428 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
27430 static bool
27432 {
27433 tree scope;
27435 /* [temp.dep.type]
27437 A type is dependent if it is:
27439 -- a template parameter. Template template parameters are types
27440 for us (since TYPE_P holds true for them) so we handle
27441 them here. */
27445 /* -- a qualified-id with a nested-name-specifier which contains a
27446 class-name that names a dependent type or whose unqualified-id
27447 names a dependent type. */
27451 /* An alias template specialization can be dependent even if the
27452 resulting type is not. */
27456 /* -- a cv-qualified type where the cv-unqualified type is
27457 dependent.
27458 No code is necessary for this bullet; the code below handles
27459 cv-qualified types, and we don't want to strip aliases with
27460 TYPE_MAIN_VARIANT because of DR 1558. */
27461 /* -- a compound type constructed from any dependent type. */
27469 {
27470 tree arg_type;
27475 arg_type;
27481 /* A value-dependent noexcept-specifier makes the type dependent. */
27484 }
27485 /* -- an array type constructed from any dependent type or whose
27486 size is specified by a constant expression that is
27487 value-dependent.
27489 We checked for type- and value-dependence of the bounds in
27490 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
27492 {
27497 }
27499 /* -- a template-id in which either the template name is a template
27500 parameter ... */
27503 /* ... or any of the template arguments is a dependent type or
27504 an expression that is type-dependent or value-dependent. */
27506 && (any_dependent_template_arguments_p
27510 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
27511 dependent; if the argument of the `typeof' expression is not
27512 type-dependent, then it should already been have resolved. */
27518 /* A template argument pack is dependent if any of its packed
27519 arguments are. */
27521 {
27526 }
27528 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
27529 be template parameters. */
27539 /* The standard does not specifically mention types that are local
27540 to template functions or local classes, but they should be
27541 considered dependent too. For example:
27543 template <int I> void f() {
27544 enum E { a = I };
27545 S<sizeof (E)> s;
27546 }
27548 The size of `E' cannot be known until the value of `I' has been
27549 determined. Therefore, `E' must be considered dependent. */
27553 /* Don't use type_dependent_expression_p here, as it can lead
27554 to infinite recursion trying to determine whether a lambda
27555 nested in a lambda is dependent (c++/47687). */
27559 && (any_dependent_template_arguments_p
27563 /* Other types are non-dependent. */
27565 }
27567 /* Returns TRUE if TYPE is dependent, in the sense of
27568 [temp.dep.type]. Note that a NULL type is considered dependent. */
27570 bool
27572 {
27573 /* If there are no template parameters in scope, then there can't be
27574 any dependent types. */
27576 {
27577 /* If we are not processing a template, then nobody should be
27578 providing us with a dependent type. */
27582 }
27584 /* If the type is NULL, we have not computed a type for the entity
27585 in question; in that case, the type is dependent. */
27589 /* Erroneous types can be considered non-dependent. */
27593 /* If we have not already computed the appropriate value for TYPE,
27594 do so now. */
27596 {
27599 }
27602 }
27604 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
27605 lookup. In other words, a dependent type that is not the current
27606 instantiation. */
27608 bool
27610 {
27613 }
27615 /* True if we might find more declarations in SCOPE during instantiation than
27616 we can when parsing the template. */
27618 bool
27620 {
27622 }
27624 /* T is a SCOPE_REF. Return whether it represents a non-static member of
27625 an unknown base of 'this' (and is therefore instantiation-dependent). */
27627 static bool
27629 {
27646 }
27648 /* T is a SCOPE_REF; return whether we need to consider it
27649 instantiation-dependent so that we can check access at instantiation
27650 time even though we know which member it resolves to. */
27652 static bool
27654 {
27662 else
27664 }
27666 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
27667 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
27668 expression. */
27670 /* Note that this predicate is not appropriate for general expressions;
27671 only constant expressions (that satisfy potential_constant_expression)
27672 can be tested for value dependence. */
27674 bool
27676 {
27680 /* A type-dependent expression is also value-dependent. */
27685 {
27687 /* A dependent member function of the current instantiation. */
27691 /* A dependent member function of the current instantiation. */
27698 /* A name that has not been looked up -- must be dependent. */
27702 /* A non-type template parm. */
27706 /* A non-type template parm. */
27712 /* A constant with literal type and is initialized
27713 with an expression that is value-dependent. */
27715 /* FIXME cp_finish_decl doesn't fold reference initializers. */
27719 {
27722 /* __PRETTY_FUNCTION__ inside a template function is dependent
27723 on the name of the function. */
27725 /* It might be used in a template, but not a template
27726 function, in which case its DECL_VALUE_EXPR will be
27727 "top level". */
27730 }
27739 /* These expressions are value-dependent if the type to which
27740 the cast occurs is dependent or the expression being casted
27741 is value-dependent. */
27742 {
27748 /* A functional cast has a list of operands. */
27751 {
27752 /* If there are no operands, it must be an expression such
27753 as "int()". This should not happen for aggregate types
27754 because it would form non-constant expressions. */
27759 }
27769 }
27774 /* FALLTHRU */
27777 /* A `sizeof' expression is value-dependent if the operand is
27778 type-dependent or is a pack expansion. */
27787 /* An 'encode' expression is value-dependent if the operand is
27788 type-dependent. */
27797 /* All instantiation-dependent expressions should also be considered
27798 value-dependent. */
27806 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
27807 is value-dependent. */
27814 {
27831 }
27842 {
27846 }
27849 /* Treat all requires-expressions as value-dependent so
27850 we don't try to fold them. */
27857 {
27864 {
27866 /* In a call to a constexpr member function, look through the
27867 implicit ADDR_EXPR on the object argument so that it doesn't
27868 cause the call to be considered value-dependent. We also
27869 look through it in potential_constant_expression. */
27876 }
27878 }
27885 {
27887 tree val;
27894 }
27897 /* Treat a GNU statement expression as dependent to avoid crashing
27898 under instantiate_non_dependent_expr; it can't be constant. */
27903 /* The second operand is a type, which type_dependent_expression_p
27904 (and therefore value_dependent_expression_p) doesn't want to see. */
27910 /* A constant expression is value-dependent if any subexpression is
27911 value-dependent. */
27913 {
27920 {
27924 {
27927 /* In some cases, some of the operands may be missing.
27928 (For example, in the case of PREDECREMENT_EXPR, the
27929 amount to increment by may be missing.) That doesn't
27930 make the expression dependent. */
27933 }
27934 }
27938 }
27940 }
27942 /* The expression is not value-dependent. */
27944 }
27946 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
27947 [temp.dep.expr]. Note that an expression with no type is
27948 considered dependent. Other parts of the compiler arrange for an
27949 expression with type-dependent subexpressions to have no type, so
27950 this function doesn't have to be fully recursive. */
27952 bool
27954 {
27965 /* An unresolved name is always dependent. */
27971 /* A lambda-expression in template context is dependent. dependent_type_p is
27972 true for a lambda in the scope of a class or function template, but that
27973 doesn't cover all template contexts, like a default template argument. */
27977 /* A fold expression is type-dependent. */
27984 /* Some expression forms are never type-dependent. */
27997 /* The types of these expressions depends only on the type to which
27998 the cast occurs. */
28007 /* The types of these expressions depends only on the type created
28008 by the expression. */
28011 {
28012 /* For NEW_EXPR tree nodes created inside a template, either
28013 the object type itself or a TREE_LIST may appear as the
28014 operand 1. */
28017 /* This is an array type. We need to check array dimensions
28018 as well. */
28020 || value_dependent_expression_p
28022 /* Array type whose dimension has to be deduced. */
28026 else
28028 }
28031 {
28035 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
28036 contains an identifier associated by name lookup with one or more
28037 declarations declared with a dependent type, or...a
28038 nested-name-specifier or qualified-id that names a member of an
28039 unknown specialization. */
28042 }
28052 {
28057 }
28059 /* A static data member of the current instantiation with incomplete
28060 array type is type-dependent, as the definition and specializations
28061 can have different bounds. */
28068 /* An array of unknown bound depending on a variadic parameter, eg:
28070 template<typename... Args>
28071 void foo (Args... args)
28072 {
28073 int arr[] = { args... };
28074 }
28076 template<int... vals>
28077 void bar ()
28078 {
28079 int arr[] = { vals... };
28080 }
28082 If the array has no length and has an initializer, it must be that
28083 we couldn't determine its length in cp_complete_array_type because
28084 it is dependent. */
28092 /* Pull a FUNCTION_DECL out of a BASELINK if we can. */
28094 {
28099 }
28101 /* A function or variable template-id is type-dependent if it has any
28102 dependent template arguments. */
28106 {
28107 /* Consider the innermost template arguments, since those are the ones
28108 that come from the template-id; the template arguments for the
28109 enclosing class do not make it type-dependent unless they are used in
28110 the type of the decl. */
28112 && (any_dependent_template_arguments_p
28115 }
28117 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
28118 type-dependent. Checking this is important for functions with auto return
28119 type, which looks like a dependent type. */
28128 {
28132 }
28134 /* Otherwise, its constraints could still depend on outer template parameters
28135 from its (dependent) scope. */
28137 /* As an optimization, check this cheaper sufficient condition first.
28138 (At this point we've established that we're looking at a member of
28139 a dependent class, so it makes sense to start treating say undeduced
28140 auto as dependent.) */
28145 /* Always dependent, on the number of arguments if nothing else. */
28150 {
28155 {
28161 }
28162 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
28166 /* CO_AWAIT/YIELD_EXPR with unknown type is always dependent. */
28172 {
28177 }
28180 {
28187 }
28196 }
28198 /* The type of a non-type template parm declared with a placeholder type
28199 depends on the corresponding template argument, even though
28200 placeholders are not normally considered dependent. */
28207 /* Dependent type attributes might not have made it from the decl to
28208 the type yet. */
28214 }
28216 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
28217 type-dependent if the expression refers to a member of the current
28218 instantiation and the type of the referenced member is dependent, or the
28219 class member access expression refers to a member of an unknown
28220 specialization.
28222 This function returns true if the OBJECT in such a class member access
28223 expression is of an unknown specialization. */
28225 bool
28227 {
28228 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
28229 dependent. */
28234 }
28236 /* walk_tree callback function for instantiation_dependent_expression_p,
28237 below. Returns non-zero if a dependent subexpression is found. */
28239 static tree
28242 {
28244 {
28245 /* We don't have to worry about decltype currently because decltype
28246 of an instantiation-dependent expr is a dependent type. This
28247 might change depending on the resolution of DR 1172. */
28250 }
28253 {
28254 /* Don't treat an argument list as dependent just because it has no
28255 TREE_TYPE. */
28266 /* We'll check value-dependence separately. */
28269 /* Handle expressions with type operands. */
28274 {
28279 {
28282 else
28283 {
28286 }
28287 }
28289 }
28293 /* In a template, finish_class_member_access_expr creates a
28294 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
28295 type-dependent, so that we can check access control at
28296 instantiation time (PR 42277). See also Core issue 1273. */
28303 else
28306 /* Treat statement-expressions as dependent. */
28310 /* Treat requires-expressions as dependent. */
28321 /* Before C++17, a noexcept-specifier isn't part of the function type
28322 so it doesn't affect type dependence, but we still want to consider it
28323 for instantiation dependence. */
28332 }
28336 else
28338 }
28340 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
28341 sense defined by the ABI:
28343 "An expression is instantiation-dependent if it is type-dependent
28344 or value-dependent, or it has a subexpression that is type-dependent
28345 or value-dependent."
28347 Except don't actually check value-dependence for unevaluated expressions,
28348 because in sizeof(i) we don't care about the value of i. Checking
28349 type-dependence will in turn check value-dependence of array bounds/template
28350 arguments as needed. */
28352 bool
28354 {
28355 tree result;
28366 }
28368 /* As above, but also check value-dependence of the expression as a whole. */
28370 bool
28372 {
28374 || (processing_template_decl
28377 }
28379 /* Like type_dependent_expression_p, but it also works while not processing
28380 a template definition, i.e. during substitution or mangling. */
28382 bool
28384 {
28390 }
28392 /* Returns TRUE if ARGS contains a type-dependent expression. */
28394 bool
28396 {
28398 tree arg;
28401 {
28404 }
28406 }
28408 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
28409 expressions) contains any type-dependent expressions. */
28411 bool
28413 {
28419 }
28421 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
28422 expressions) contains any value-dependent expressions. */
28424 bool
28426 {
28432 }
28434 /* Returns TRUE if the ARG (a template argument) is dependent. */
28436 bool
28438 {
28442 /* Assume a template argument that was wrongly written by the user
28443 is dependent. This is consistent with what
28444 any_dependent_template_arguments_p [that calls this function]
28445 does. */
28455 {
28458 /* A member template of a dependent class is not necessarily
28459 type-dependent, but it is a dependent template argument because it
28460 will be a member of an unknown specialization to that template. */
28463 }
28465 {
28471 }
28474 else
28476 }
28478 /* Identify any expressions that use function parms. */
28480 static tree
28482 {
28485 {
28488 }
28490 }
28492 /* Returns true if a type specialization formed using the template
28493 arguments ARGS needs to use structural equality. */
28495 bool
28497 {
28507 {
28510 {
28516 {
28517 /* Look inside the argument pack. */
28520 }
28523 {
28532 /* An any_targ_node argument (added by add_defaults_to_ttp)
28533 makes the corresponding specialization not canonicalizable,
28534 since template_args_equal always return true for it. We
28535 may see this when called from bind_template_template_parm. */
28537 /* Checking current_function_decl because this structural
28538 comparison is only necessary for redeclaration. */
28541 && (cp_walk_tree_without_duplicates
28543 /* The identity of a class template specialization that uses
28544 a function parameter depends on the identity of the function.
28545 And if this specialization appeared in the trailing return
28546 type thereof, we don't know the identity of the function
28547 (e.g. if it's a redeclaration or a new function) until we
28548 form its signature and go through duplicate_decls. Thus
28549 it's unsafe to decide on a canonical type now (which depends
28550 on the DECL_CONTEXT of the function parameter, which can get
28551 mutated after the fact by duplicate_decls), so just require
28552 structural equality in this case (PR52830). */
28554 }
28555 }
28556 }
28559 }
28561 /* Returns true if ARGS (a collection of template arguments) contains
28562 any dependent arguments. */
28564 bool
28566 {
28576 {
28581 }
28584 }
28586 /* Returns true if ARGS contains any errors. */
28588 bool
28590 {
28598 {
28601 else
28603 }
28609 {
28614 }
28617 }
28619 /* Returns TRUE if the template TMPL is type-dependent. */
28621 bool
28623 {
28625 {
28630 }
28632 /* Template template parameters are dependent. */
28636 /* So are names that have not been looked up. */
28640 }
28642 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
28644 bool
28646 {
28649 }
28651 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
28652 are dependent. */
28654 bool
28656 {
28663 {
28688 {
28692 }
28696 {
28700 {
28706 /* If this loop has a class iterator with != comparison
28707 with increment other than i++/++i/i--/--i, make sure the
28708 increment is constant. */
28711 {
28714 else
28718 }
28719 }
28720 }
28721 }
28724 }
28726 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
28727 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
28728 no such TYPE can be found. Note that this function peers inside
28729 uninstantiated templates and therefore should be used only in
28730 extremely limited situations. ONLY_CURRENT_P restricts this
28731 peering to the currently open classes hierarchy (which is required
28732 when comparing types). */
28734 tree
28736 {
28737 tree scope;
28738 tree name;
28739 tree decl;
28741 tree pushed_scope;
28742 tree result;
28747 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
28750 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
28751 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of a
28752 TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL
28753 representing the typedef. In that case TYPE_IDENTIFIER (type) is
28754 not the non-qualified identifier of the TYPENAME_TYPE anymore.
28755 So by getting the TYPE_IDENTIFIER of the _main declaration_ of
28756 the TYPENAME_TYPE instead, we avoid messing up with a possible
28757 typedef variant case. */
28760 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
28761 it first before we can figure out what NAME refers to. */
28763 {
28765 /* Given a class template A with a dependent base with nested type C,
28766 typedef typename A::C::C C will land us here, as trying to resolve
28767 the initial A::C leads to the local C typedef, which leads back to
28768 A::C::C. So we break the recursion now. */
28770 else
28772 }
28773 /* If we don't know what SCOPE refers to, then we cannot resolve the
28774 TYPENAME_TYPE. */
28777 /* If this is a typedef, we don't want to look inside (c++/11987). */
28780 /* If SCOPE isn't the template itself, it will not have a valid
28781 TYPE_FIELDS list. */
28783 /* scope is either the template itself or a compatible instantiation
28784 like X<T>, so look up the name in the original template. */
28786 /* If scope has no fields, it can't be a current instantiation. Check this
28787 before currently_open_class to avoid infinite recursion (71515). */
28790 /* If the SCOPE is not the current instantiation, there's no reason
28791 to look inside it. */
28794 /* Enter the SCOPE so that name lookup will be resolved as if we
28795 were in the class definition. In particular, SCOPE will no
28796 longer be considered a dependent type. */
28798 /* Look up the declaration. */
28800 tf_warning_or_error);
28804 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
28805 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
28811 {
28815 }
28818 {
28819 /* Obtain the template and the arguments. */
28822 {
28823 /* We get here with a plain identifier because a previous tentative
28824 parse of the nested-name-specifier as part of a ptr-operator saw
28825 ::template X<A>. The use of ::template is necessary in a
28826 ptr-operator, but wrong in a declarator-id.
28828 [temp.names]: In a qualified-id of a declarator-id, the keyword
28829 template shall not appear at the top level. */
28833 }
28835 /* Instantiate the template. */
28841 }
28843 /* Leave the SCOPE. */
28847 /* If we failed to resolve it, return the original typename. */
28851 /* If lookup found a typename type, resolve that too. */
28853 {
28854 /* Ill-formed programs can cause infinite recursion here, so we
28855 must catch that. */
28859 }
28861 /* Qualify the resulting type. */
28867 }
28869 /* EXPR is an expression which is not type-dependent. Return a proxy
28870 for EXPR that can be used to compute the types of larger
28871 expressions containing EXPR. */
28873 tree
28875 {
28877 tree inner_expr;
28879 /* When checking, try to get a constant value for all non-dependent
28880 expressions in order to expose bugs in *_dependent_expression_p
28881 and constexpr. This can affect code generation, see PR70704, so
28882 only do this for -fchecking=2. */
28885 /* Don't do this during nsdmi parsing as it can lead to
28886 unexpected recursive instantiations. */
28888 /* Don't do this during concept processing either and for
28889 the same reason. */
28895 /* Preserve OVERLOADs; the functions must be available to resolve
28896 types. */
28907 /* There is no need to return a proxy for a variable, parameter
28908 or enumerator. */
28912 /* Preserve string constants; conversions from string constants to
28913 "char *" are allowed, even though normally a "const char *"
28914 cannot be used to initialize a "char *". */
28917 /* Preserve void and arithmetic constants, as an optimization -- there is no
28918 reason to create a new node. */
28923 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
28924 There is at least one place where we want to know that a
28925 particular expression is a throw-expression: when checking a ?:
28926 expression, there are special rules if the second or third
28927 argument is a throw-expression. */
28931 /* Don't wrap an initializer list, we need to be able to look inside. */
28935 /* Don't wrap a dummy object, we need to be able to test for it. */
28953 /* If the type is unknown, it can't really be non-dependent */
28956 /* Otherwise, build a NON_DEPENDENT_EXPR. */
28959 }
28961 /* ARGS is a vector of expressions as arguments to a function call.
28962 Replace the arguments with equivalent non-dependent expressions.
28963 This modifies ARGS in place. */
28965 void
28967 {
28969 tree arg;
28972 {
28976 }
28977 }
28979 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
28980 TEMPLATE_TYPE_PARM with a level one deeper than the actual template parms,
28981 by default. If set_canonical is true, we set TYPE_CANONICAL on it. */
28983 static tree
28985 {
29001 }
29003 tree
29005 {
29007 }
29009 tree
29011 {
29013 }
29015 /* Return a C++17 deduction placeholder for class template TMPL.
29016 There are represented as an 'auto' with the special level 0 and
29017 CLASS_PLACEHOLDER_TEMPLATE set. */
29019 tree
29021 {
29024 /* Our canonical type depends on the placeholder. */
29027 }
29029 /* True iff T is a C++17 class template deduction placeholder. */
29031 bool
29033 {
29035 }
29037 /* Make a "constrained auto" type-specifier. This is an auto or
29038 decltype(auto) type with constraints that must be associated after
29039 deduction. The constraint is formed from the given concept CON
29040 and its optional sequence of template arguments ARGS.
29042 TYPE must be the result of make_auto_type or make_decltype_auto_type. */
29044 static tree
29046 {
29047 /* Build the constraint. */
29059 /* Our canonical type depends on the constraint. */
29062 /* Attach the constraint to the type declaration. */
29064 }
29066 /* Make a "constrained auto" type-specifier. */
29068 tree
29070 {
29073 }
29075 /* Make a "constrained decltype(auto)" type-specifier. */
29077 tree
29079 {
29082 }
29084 /* Returns true if the placeholder type constraint T has any dependent
29085 (explicit) template arguments. */
29087 static bool
29089 {
29094 {
29097 }
29104 }
29106 /* Build and return a concept definition. Like other templates, the
29107 CONCEPT_DECL node is wrapped by a TEMPLATE_DECL. This returns the
29108 the TEMPLATE_DECL. */
29110 tree
29112 {
29118 /* A concept-definition shall not have associated constraints. */
29120 {
29123 }
29125 /* A concept-definition shall appear in namespace scope. Templates
29126 aren't allowed in block scope, so we only need to check for class
29127 scope. */
29129 {
29132 }
29135 {
29138 }
29140 /* Initially build the concept declaration; its type is bool. */
29147 /* Push the enclosing template. */
29149 }
29151 /* Given type ARG, return std::initializer_list<ARG>. */
29153 static tree
29155 {
29159 {
29163 "deducing from brace-enclosed initializer list"
29167 }
29173 }
29175 /* Replace auto in TYPE with std::initializer_list<auto>. */
29177 static tree
29179 {
29186 }
29188 /* Hash traits for hashing possibly constrained 'auto'
29189 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
29192 {
29195 };
29197 /* Hash the 'auto' T. */
29199 inline hashval_t
29201 {
29203 /* Matching constrained-type-specifiers denote the same template
29204 parameter, so hash the constraint. */
29206 else
29207 /* But unconstrained autos are all separate, so just hash the pointer. */
29209 }
29211 /* Compare two 'auto's. */
29215 {
29222 /* Two unconstrained autos are distinct. */
29227 }
29229 /* for_each_template_parm callback for extract_autos: if t is a (possibly
29230 constrained) auto, add it to the vector. */
29232 static int
29234 {
29237 {
29238 /* All the autos were built with index 0; fix that up now. */
29242 /* If this is a repeated constrained-type-specifier, use the index we
29243 chose before. */
29245 else
29246 {
29247 /* Otherwise this is new, so use the current count. */
29250 }
29252 }
29254 /* Always keep walking. */
29256 }
29258 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
29259 says they can appear anywhere in the type. */
29261 static tree
29263 {
29271 {
29275 }
29278 }
29280 /* The stem for deduction guide names. */
29283 /* Return the name for a deduction guide for class template TMPL. */
29285 tree
29287 {
29298 }
29300 /* True if NAME is the name of a deduction guide. */
29302 bool
29304 {
29308 }
29310 /* True if FN is a deduction guide. */
29312 bool
29314 {
29319 }
29321 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
29323 bool
29325 {
29332 }
29334 /* True if FN is a guide generated from a constructor template. */
29336 bool
29338 {
29346 }
29348 /* True if FN is an aggregate initialization guide or the copy deduction
29349 guide. */
29351 bool
29353 {
29357 /* Explicitly declared. */
29360 /* Derived from a constructor. */
29363 }
29365 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
29366 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
29367 template parameter types. Note that the handling of template template
29368 parameters relies on current_template_parms being set appropriately for the
29369 new template. */
29371 static tree
29374 {
29380 tree newtype;
29383 {
29387 }
29388 else
29389 {
29392 {
29393 // Substitute once to fix references to other template parameters.
29396 // Now substitute again to reduce the level of the auto.
29399 }
29400 else
29403 }
29405 tree newdecl
29410 tree newidx;
29413 {
29422 {
29427 // First create a copy (ttargs) of tsubst_args with an
29428 // additional level for the template template parameter's own
29429 // template parameters (ttparms).
29430 tree ttparms = (INNERMOST_TEMPLATE_PARMS
29438 // Substitute ttargs into ttparms to fix references to
29439 // other template parameters.
29442 // Now substitute again with args based on tparms, to reduce
29443 // the level of the ttparms.
29446 complain);
29447 // Finally, tack the adjusted parms onto tparms.
29450 // As with all template template parms, the parameter list captured
29451 // by this template template parm that corresponds to its own level
29452 // should be empty. This avoids infinite recursion when structurally
29453 // comparing two such rewritten template template parms (PR102479).
29458 // All done.
29460 }
29464 else
29466 }
29467 else
29468 {
29470 tree newconst
29482 }
29485 }
29487 /* As rewrite_template_parm, but for the whole TREE_LIST representing a
29488 template parameter. */
29490 static tree
29493 {
29508 }
29510 /* Returns a C++17 class deduction guide template based on the constructor
29511 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
29512 guide, REFERENCE_TYPE for an implicit copy/move guide, or TREE_LIST for an
29513 aggregate initialization guide. OUTER_ARGS are the template arguments
29514 for the enclosing scope of the class. */
29516 static tree
29518 {
29522 location_t loc;
29526 {
29530 }
29533 {
29535 {
29539 else
29541 }
29544 else
29554 }
29555 else
29556 {
29562 fn_tmpl
29570 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
29571 fully specialized args for the enclosing class. Strip those off, as
29572 the deduction guide won't have those template parameters. */
29575 /* Discard the 'this' parameter. */
29583 {
29586 /* For a member template constructor, we need to flatten the two
29587 template parameter lists into one, and then adjust the function
29588 signature accordingly. This gets...complicated. */
29591 /* For a member template we should have two levels of parms/args, one
29592 for the class and one for the constructor. We stripped
29593 specialized args for further enclosing classes above. */
29597 /* Template args for translating references to the two-level template
29598 parameters into references to the one-level template parameters we
29599 are creating. */
29604 /* Template parms for the constructor template. */
29607 /* Template parms for the class template. */
29611 /* Template parms for the deduction guide start as a copy of the
29612 template parms for the class. We set current_template_parms for
29613 lookup_template_class_1. */
29619 /* Now we need to rewrite the constructor parms to append them to the
29620 class parms. */
29622 {
29626 tree newelt
29632 }
29634 /* Now we have a final set of template parms to substitute into the
29635 function signature. */
29642 {
29644 /* FIXME: We'd like to avoid substituting outer template
29645 arguments into the constraint ahead of time, but the
29646 construction of tsubst_args assumes that outer arguments
29647 are already substituted in. */
29650 }
29652 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped if
29653 cp_unevaluated_operand. */
29654 cp_evaluated ev;
29657 }
29658 else
29659 {
29660 /* Substitute in the same arguments to rewrite class members into
29661 references to members of an unknown specialization. */
29662 cp_evaluated ev;
29666 {
29668 /* FIXME: As above. */
29671 }
29672 }
29677 }
29680 {
29681 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
29685 }
29689 FUNCTION_DECL,
29704 }
29706 /* Add to LIST the member types for the reshaped initializer CTOR. */
29708 static tree
29710 {
29714 {
29718 {
29724 }
29728 /* Give the trailing pack expansion parameter a default argument to
29729 match aggregate initialization behavior, even if we deduce the
29730 length of the pack separately to more than we have initializers. */
29732 /* if ei is of array type and xi is a braced-init-list or string literal,
29733 Ti is an rvalue reference to the declared type of ei */
29738 {
29740 ftype = cp_build_qualified_type
29742 ftype = (cp_build_reference_type
29744 }
29746 }
29749 }
29751 /* Return whether ETYPE is, or is derived from, a specialization of TMPL. */
29753 static bool
29755 {
29761 tree tparms = (INNERMOST_TEMPLATE_PARMS
29768 }
29772 /* Return a C++20 aggregate deduction candidate for TYPE initialized from
29773 INIT. */
29775 static tree
29777 {
29785 {
29791 }
29793 /* We might be creating a guide for a class member template, e.g.,
29795 template<typename U> struct A {
29796 template<typename T> struct B { T t; };
29797 };
29799 At this point, A will have been instantiated. Below, we need to
29800 use both A<U>::B<T> (TEMPLATE_TYPE) and A<int>::B<T> (TYPE) types. */
29801 const bool member_template_p
29805 tree template_type = (member_template_p
29811 /* No aggregate candidate for copy-initialization. */
29813 {
29817 }
29819 /* If we encounter a problem, we just won't add the candidate. */
29824 {
29829 /* If we're creating a deduction guide for a member class template,
29830 we've used the original template pattern type for the reshape_init
29831 above; this is done because we want PARMS to be a template parameter
29832 type, something that can be deduced when used as a function template
29833 parameter. At this point the outer class template has already been
29834 partially instantiated (we deferred the deduction until the enclosing
29835 scope is non-dependent). Therefore we have to partially instantiate
29836 PARMS, so that its template level is properly reduced and we don't get
29837 mismatches when deducing types using the guide with PARMS. */
29839 {
29843 }
29844 }
29846 {
29849 len;
29851 {
29857 }
29858 }
29859 else
29860 /* Aggregate initialization doesn't apply to an initializer expression. */
29864 {
29870 }
29873 }
29875 /* UGUIDES are the deduction guides for the underlying template of alias
29876 template TMPL; adjust them to be deduction guides for TMPL. */
29878 static tree
29880 {
29881 /* [over.match.class.deduct]: When resolving a placeholder for a deduced
29882 class type (9.2.8.2) where the template-name names an alias template A,
29883 the defining-type-id of A must be of the form
29885 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
29887 as specified in 9.2.8.2. The guides of A are the set of functions or
29888 function templates formed as follows. For each function or function
29889 template f in the guides of the template named by the simple-template-id
29890 of the defining-type-id, the template arguments of the return type of f
29891 are deduced from the defining-type-id of A according to the process in
29892 13.10.2.5 with the exception that deduction does not fail if not all
29893 template arguments are deduced. Let g denote the result of substituting
29894 these deductions into f. If substitution succeeds, form a function or
29895 function template f' with the following properties and add it to the set
29896 of guides of A:
29898 * The function type of f' is the function type of g.
29900 * If f is a function template, f' is a function template whose template
29901 parameter list consists of all the template parameters of A (including
29902 their default template arguments) that appear in the above deductions or
29903 (recursively) in their default template arguments, followed by the
29904 template parameters of f that were not deduced (including their default
29905 template arguments), otherwise f' is not a function template.
29907 * The associated constraints (13.5.2) are the conjunction of the
29908 associated constraints of g and a constraint that is satisfied if and only
29909 if the arguments of A are deducible (see below) from the return type.
29911 * If f is a copy deduction candidate (12.4.1.8), then f' is considered to
29912 be so as well.
29914 * If f was generated from a deduction-guide (12.4.1.8), then f' is
29915 considered to be so as well.
29917 * The explicit-specifier of f' is the explicit-specifier of g (if
29918 any). */
29920 /* This implementation differs from the above in two significant ways:
29922 1) We include all template parameters of A, not just some.
29923 2) The added constraint is same_type instead of deducible.
29925 I believe that while it's probably possible to construct a testcase that
29926 behaves differently with this simplification, it should have the same
29927 effect for real uses. Including all template parameters means that we
29928 deduce all parameters of A when resolving the call, so when we're in the
29929 constraint we don't need to deduce them again, we can just check whether
29930 the deduction produced the desired result. */
29939 {
29946 {
29950 /* Deduce template arguments for f from the type-id of A. */
29958 /* The number of parms for f' is the number of parms for A plus
29959 non-deduced parms of f. */
29967 /* Set current_template_parms as in build_deduction_guide. */
29972 /* First copy over the parms of A. */
29975 /* Now rewrite the non-deduced parms of f. */
29978 {
29986 }
29989 /* Substitute the deduced arguments plus the rewritten template
29990 parameters into f to get g. This covers the type, copyness,
29991 guideness, and explicit-specifier. */
29992 tree g;
29993 {
29994 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped
29995 if cp_unevaluated_operand. */
29996 cp_evaluated ev;
29998 }
30009 /* Substitute the associated constraints. */
30016 /* Add a constraint that the return type matches the instantiation of
30017 A with the same template arguments. */
30020 /* FIXME this should mean they don't compare as equivalent. */
30022 {
30025 }
30028 {
30031 }
30032 }
30033 else
30034 {
30035 /* For a non-template deduction guide, if the arguments of A aren't
30036 deducible from the return type, don't add the candidate. */
30044 }
30047 }
30050 }
30052 /* Return artificial deduction guides built from the constructors of class
30053 template TMPL. */
30055 static tree
30057 {
30062 {
30067 }
30072 {
30073 /* Skip inherited constructors. */
30079 }
30081 /* Add implicit default constructor deduction guide. */
30083 {
30085 complain);
30087 }
30089 /* Add copy guide. */
30090 {
30093 complain);
30095 }
30098 }
30102 /* Return the non-aggregate deduction guides for deducible template TMPL. The
30103 aggregate candidate is added separately because it depends on the
30104 initializer. Set ANY_DGUIDES_P if we find a non-implicit deduction
30105 guide. */
30107 static tree
30109 {
30112 {
30116 complain);
30117 }
30118 else
30119 {
30125 else
30127 }
30129 /* Cache the deduction guides for a template. We also remember the result of
30130 lookup, and rebuild everything if it changes; should be very rare. */
30134 {
30138 }
30139 else
30140 {
30143 }
30148 else
30149 {
30153 }
30157 }
30159 /* Return whether TMPL is a (class template argument-) deducible template. */
30161 bool
30163 {
30164 /* A deducible template is either a class template or is an alias template
30165 whose defining-type-id is of the form
30167 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
30169 where the nested-name-specifier (if any) is non-dependent and the
30170 template-name of the simple-template-id names a deducible template. */
30181 }
30183 /* Deduce template arguments for the class template placeholder PTYPE for
30184 template TMPL based on the initializer INIT, and return the resulting
30185 type. */
30187 static tree
30190 {
30191 /* We should have handled this in the caller. */
30195 /* If the class was erroneous, don't try to deduce, because that
30196 can generate a lot of diagnostic. */
30202 /* Wait until the enclosing scope is non-dependent. */
30207 /* Initializing one placeholder from another. */
30218 {
30222 }
30224 {
30226 {
30227 /* Be permissive with equivalent alias templates. */
30230 bool complained
30232 "alias template deduction only available "
30237 {
30240 }
30241 }
30242 else
30244 }
30246 /* Wait until the initializer is non-dependent. */
30250 /* Don't bother with the alias rules for an equivalent template. */
30263 {
30268 {
30269 /* As an exception, the first phase in 16.3.1.7 (considering the
30270 initializer list as a single argument) is omitted if the
30271 initializer list consists of a single expression of type cv U,
30272 where U is a specialization of C or a class derived from a
30273 specialization of C. */
30277 }
30280 else
30282 }
30285 else
30288 /* Do this now to avoid problems with erroneous args later on. */
30298 /* Prune explicit deduction guides in copy-initialization context (but
30299 not copy-list-initialization). */
30302 {
30308 {
30309 /* Found a nonconverting guide, prune the candidates. */
30316 }
30317 }
30325 /* If this is list-initialization and the class has a list guide, first
30326 try deducing from the list as a single argument, as [over.match.list]. */
30328 {
30336 {
30337 /* That didn't work, now try treating the list as a sequence of
30338 arguments. */
30344 }
30345 }
30348 {
30350 " of %qT, as it has no non-explicit deduction guides or "
30353 }
30355 {
30359 }
30365 {
30367 {
30373 }
30375 }
30376 /* [over.match.list]/1: In copy-list-initialization, if an explicit
30377 constructor is chosen, the initialization is ill-formed. */
30379 {
30381 {
30383 {
30384 // TODO: Pass down location from cp_finish_decl.
30386 "explicit deduction guide selected in "
30391 }
30393 }
30394 }
30396 /* If CTAD succeeded but the type doesn't have any explicit deduction
30397 guides, this deduction might not be what the user intended. */
30399 {
30403 "%qT may not intend to support class template argument "
30407 }
30411 }
30413 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
30414 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
30415 The CONTEXT determines the context in which auto deduction is performed
30416 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
30418 OUTER_TARGS is used during template argument deduction (context == adc_unify)
30419 to properly substitute the result. It's also used in the adc_unify and
30420 adc_requirement contexts to communicate the necessary template arguments
30421 to satisfaction. OUTER_TARGS is ignored in other contexts.
30423 For partial-concept-ids, extra args may be appended to the list of deduced
30424 template arguments prior to determining constraint satisfaction. */
30426 tree
30430 {
30436 /* Defining a subset of type-dependent expressions that we can deduce
30437 from ahead of time isn't worth the trouble. */
30440 /* Similarly, we can't deduce from another undeduced decl. */
30444 /* We may be doing a partial substitution, but we still want to replace
30445 auto_node. */
30449 /* C++17 class template argument deduction. */
30453 /* Nothing we can do with this, even in deduction context. */
30458 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
30459 with either a new invented type template parameter U or, if the
30460 initializer is a braced-init-list (8.5.4), with
30461 std::initializer_list<U>. */
30463 {
30468 else
30469 {
30471 {
30475 "for deduction to %<std::initializer_list%>, use copy-"
30477 }
30479 }
30480 }
30486 {
30487 /* We don't recurse here because we can't deduce from a nested
30488 initializer_list. */
30492 }
30493 else
30496 tree targs;
30501 {
30502 /* [dcl.struct.bind]/1 - if decomposition declaration has no ref-qualifiers
30503 and initializer has array type, deduce cv-qualified array type. */
30506 }
30508 {
30509 /* Figure out if INIT is an unparenthesized id-expression or an
30510 unparenthesized class member access. */
30512 /* We need to be able to tell '(r)' and 'r' apart (when it's of
30513 reference type). Only the latter is an id-expression. */
30527 }
30528 else
30529 {
30534 tree tparms;
30538 else
30539 {
30543 }
30547 DEDUCE_CALL,
30550 {
30552 /* Try again at instantiation time. */
30556 /* If type is error_mark_node a diagnostic must have been
30557 emitted by now. Also, having a mention to '<type error>'
30558 in the diagnostic is not really useful to the user. */
30559 {
30562 && (auto_node
30566 init);
30567 else
30570 DEDUCE_CALL,
30572 }
30574 }
30575 }
30577 /* Check any placeholder constraints against the deduced type. */
30581 {
30583 {
30588 /* If the constraint is dependent, we need to wait until
30589 instantiation time to resolve the placeholder. */
30592 }
30599 {
30603 {
30604 /* As in satisfy_declaration_constraints. */
30608 else
30610 }
30611 }
30615 /* HACK: Compensate for callers not always communicating all levels of
30616 outer template arguments by filling in the outermost missing levels
30617 with dummy levels before checking satisfaction. We'll still crash
30618 if the constraint depends on a template argument belonging to one of
30619 these missing levels, but this hack otherwise allows us to handle a
30620 large subset of possible constraints (including all non-dependent
30621 constraints). */
30624 {
30629 }
30632 {
30634 {
30635 auto_diagnostic_group d;
30637 {
30655 }
30657 }
30659 }
30660 }
30663 /* The outer template arguments are already substituted into type
30670 }
30672 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
30673 result. */
30675 tree
30677 {
30679 {
30682 }
30686 {
30687 /* In an abbreviated function template we didn't know we were dealing
30688 with a function template when we saw the auto return type, so rebuild
30689 the return type using an auto with the correct level. */
30694 auto_vec);
30695 /* Also rebuild the constraint info in terms of the new auto. */
30703 }
30705 }
30707 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
30708 'decltype(auto)' or a deduced class template. */
30710 bool
30712 {
30717 else
30719 }
30721 /* for_each_template_parm callback for type_uses_auto. */
30723 int
30725 {
30727 }
30729 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
30730 a use of `auto'. Returns NULL_TREE otherwise. */
30732 tree
30734 {
30738 {
30739 /* The Concepts TS allows multiple autos in one type-specifier; just
30740 return the first one we find, do_auto_deduction will collect all of
30741 them. */
30745 else
30747 }
30748 else
30750 }
30752 /* Report ill-formed occurrences of auto types in ARGUMENTS. If
30753 concepts are enabled, auto is acceptable in template arguments, but
30754 only when TEMPL identifies a template class. Return TRUE if any
30755 such errors were reported. */
30757 bool
30759 {
30761 /* Only the concepts TS allows 'auto' as a type-id; it'd otherwise
30762 have already been rejected by the parser more generally. */
30765 /* If there were previous errors, nevermind. */
30769 /* If TMPL is an identifier, we're parsing and we can't tell yet
30770 whether TMPL is supposed to be a type, a function or a variable.
30771 We'll only be able to tell during template substitution, so we
30772 expect to be called again then. If concepts are enabled and we
30773 know we have a type, we're ok. */
30780 /* Quickly search for any occurrences of auto; usually there won't
30781 be any, and then we'll avoid allocating the vector. */
30789 {
30794 }
30797 }
30799 /* Recursively walk over && expressions searching for EXPR. Return a reference
30800 to that expression. */
30803 {
30807 {
30812 }
30814 }
30816 /* Convert the generic type parameters in PARM that match the types given in the
30817 range [START_IDX, END_IDX) from the current_template_parms into generic type
30818 packs. */
30820 tree
30822 {
30833 {
30834 /* Create a distinct parameter pack type from the current parm and add it
30835 to the replacement args to tsubst below into the generic function
30836 parameter. */
30850 /* Replace the current template parameter with new pack. */
30853 /* Surgically adjust the associated constraint of adjusted parameter
30854 and it's corresponding contribution to the current template
30855 requirements. */
30857 {
30863 /* If there was a constraint, we also need to replace that in
30864 the template requirements, which we've already built. */
30868 }
30869 }
30875 /* If there are more levels then build up the replacement with the outer
30876 template parms. */
30880 replacement);
30883 }
30885 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
30886 0..N-1. */
30888 void
30890 {
30893 integer_type_node,
30894 NULL_TREE),
30898 CP_BUILT_IN_INTEGER_PACK);
30899 }
30901 /* Walk the decl or type specialization table calling FN on each
30902 entry. */
30904 void
30908 {
30914 }
30916 /* Lookup the specialization of *ELT, in the decl or type
30917 specialization table. Return the SPEC that's already there, or
30918 NULL if nothing. */
30920 tree
30922 {
30932 }
30934 /* Return flags encoding whether SPEC is on the instantiation and/or
30935 specialization lists of TMPL. */
30937 unsigned
30939 {
30945 {
30948 }
30953 /* Only need to search if DECL is a partial specialization. */
30957 {
30960 }
30963 }
30965 /* Add a new specialization described by SPEC. DECL is the
30966 maybe-template decl and FLAGS is as returned from
30967 get_mergeable_specialization_flags. */
30969 void
30972 {
30975 {
30984 {
30987 }
30988 }
30991 {
30994 /* We don't distinguish different constrained partial type
30995 specializations, so there could be duplicates. Everything else
30996 must be new. */
30998 {
31004 }
31005 }
31012 {
31013 /* A partial specialization. */
31018 }
31019 }
31021 /* Set up the hash tables for template instantiations. */
31023 void
31025 {
31031 }
31033 /* Print stats about the template hash tables for -fstats. */
31035 void
31037 {
31046 }
31048 #if CHECKING_P
31052 /* Verify that build_non_dependent_expr () works, for various expressions,
31053 and that location wrappers don't affect the results. */
31055 static void
31057 {
31060 /* Verify constants, without and with location wrappers. */
31077 }
31079 /* Verify that type_dependent_expression_p () works correctly, even
31080 in the presence of location wrapper nodes. */
31082 static void
31084 {
31089 /* If no templates are involved, nothing is type-dependent. */
31095 /* Within a template, an unresolved name is always type-dependent. */
31098 /* Ensure it copes with NULL_TREE and errors. */
31102 /* A USING_DECL in a template should be type-dependent, even if wrapped
31103 with a location wrapper (PR c++/83799). */
31112 }
31114 /* Run all of the selftests within this file. */
31116 void
31118 {
31121 }