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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. */
49 /* The type of functions taking a tree, and some additional data, and
50 returning an int. */
53 /* The PENDING_TEMPLATES is a list of templates whose instantiations
54 have been deferred, either because their definitions were not yet
55 available, or because we were putting off doing the work. */
57 {
60 };
74 /* Live only within one (recursive) call to tsubst_expr. We use
75 this to pass the statement expression node from the STMT_EXPR
76 to the EXPR_STMT that is its result. */
79 // -------------------------------------------------------------------------- //
80 // Local Specialization Stack
81 //
82 // Implementation of the RAII helper for creating new local
83 // specializations.
86 {
88 ;
91 else
93 }
96 {
98 {
101 }
102 }
104 /* True if we've recursed into fn_type_unification too many times. */
108 {
111 };
113 /* The general template is not in these tables. */
118 /* Contains canonical template parameter types. The vector is indexed by
119 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
120 TREE_LIST, whose TREE_VALUEs contain the canonical template
121 parameters of various types and levels. */
124 #define UNIFY_ALLOW_NONE 0
125 #define UNIFY_ALLOW_MORE_CV_QUAL 1
126 #define UNIFY_ALLOW_LESS_CV_QUAL 2
127 #define UNIFY_ALLOW_DERIVED 4
128 #define UNIFY_ALLOW_INTEGER 8
129 #define UNIFY_ALLOW_OUTER_LEVEL 16
130 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
131 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
134 tbr_incomplete_type,
135 tbr_ambiguous_baseclass,
136 tbr_success
137 };
224 /* Make the current scope suitable for access checking when we are
225 processing T. T can be FUNCTION_DECL for instantiated function
226 template, VAR_DECL for static member variable, or TYPE_DECL for
227 for a class or alias template (needed by instantiate_decl). */
229 void
231 {
243 /* An artificial deduction guide should have the same access as
244 the constructor. */
246 else
250 {
253 }
254 }
256 /* Restore the scope set up by push_access_scope. T is the node we
257 are processing. */
259 void
261 {
271 else
273 }
275 /* Do any processing required when DECL (a member template
276 declaration) is finished. Returns the TEMPLATE_DECL corresponding
277 to DECL, unless it is a specialization, in which case the DECL
278 itself is returned. */
280 tree
282 {
289 {
290 tree type;
298 {
302 }
304 }
309 {
311 {
314 }
315 else
317 }
318 else
323 }
325 /* Create a template info node. */
327 tree
329 {
334 }
336 /* Return the template info node corresponding to T, whatever T is. */
338 tree
340 {
362 }
364 /* Returns the template nesting level of the indicated class TYPE.
366 For example, in:
367 template <class T>
368 struct A
369 {
370 template <class U>
371 struct B {};
372 };
374 A<T>::B<U> has depth two, while A<T> has depth one.
375 Both A<T>::B<int> and A<int>::B<U> have depth one, if
376 they are instantiations, not specializations.
378 This function is guaranteed to return 0 if passed NULL_TREE so
379 that, for example, `template_class_depth (current_class_type)' is
380 always safe. */
382 int
384 {
388 {
396 {
399 else
401 }
404 else
406 }
409 }
411 /* Return TRUE if NODE instantiates a template that has arguments of
412 its own, be it directly a primary template or indirectly through a
413 partial specializations. */
414 static bool
416 {
428 /* So now we know we have a specialization, but it could be a full
429 or a partial specialization. To tell which, compare the depth of
430 its template arguments with those of its context. */
439 }
441 /* Subroutine of maybe_begin_member_template_processing.
442 Returns true if processing DECL needs us to push template parms. */
444 static bool
446 {
452 }
454 /* Subroutine of maybe_begin_member_template_processing.
455 Push the template parms in PARMS, starting from LEVELS steps into the
456 chain, and ending at the beginning, since template parms are listed
457 innermost first. */
459 static void
461 {
469 current_template_parms
475 NULL);
477 {
486 {
493 /* Push the CONST_DECL. */
499 }
500 }
501 }
503 /* Restore the template parameter context for a member template, a
504 friend template defined in a class definition, or a non-template
505 member of template class. */
507 void
509 {
510 tree parms;
515 {
518 /* Disregard full specializations (c++/60999). */
521 }
524 {
529 {
532 }
535 }
537 /* Remember how many levels of template parameters we pushed so that
538 we can pop them later. */
540 }
542 /* Undo the effects of maybe_begin_member_template_processing. */
544 void
546 {
555 {
559 }
560 }
562 /* Return a new template argument vector which contains all of ARGS,
563 but has as its innermost set of arguments the EXTRA_ARGS. */
565 tree
567 {
568 tree new_args;
586 }
588 /* Like add_to_template_args, but only the outermost ARGS are added to
589 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
590 (EXTRA_ARGS) levels are added. This function is used to combine
591 the template arguments from a partial instantiation with the
592 template arguments used to attain the full instantiation from the
593 partial instantiation.
595 If ARGS is a TEMPLATE_DECL, use its parameters as args. */
597 tree
599 {
600 tree new_args;
605 {
608 }
610 /* If there are more levels of EXTRA_ARGS than there are ARGS,
611 something very fishy is going on. */
614 /* If *all* the new arguments will be the EXTRA_ARGS, just return
615 them. */
619 /* For the moment, we make ARGS look like it contains fewer levels. */
624 /* Now, we restore ARGS to its full dimensions. */
628 }
630 /* Return the N levels of innermost template arguments from the ARGS. */
632 tree
634 {
635 tree new_args;
641 /* If N is 1, just return the innermost set of template arguments. */
645 /* If we're not removing anything, just return the arguments we were
646 given. */
652 /* Make a new set of arguments, not containing the outer arguments. */
659 }
661 /* The inverse of get_innermost_template_args: Return all but the innermost
662 EXTRA_LEVELS levels of template arguments from the ARGS. */
664 static tree
666 {
667 tree new_args;
673 /* If N is 1, just return the outermost set of template arguments. */
677 /* If we're not removing anything, just return the arguments we were
678 given. */
683 /* Make a new set of arguments, not containing the inner arguments. */
690 }
692 /* We've got a template header coming up; push to a new level for storing
693 the parms. */
695 void
697 {
698 /* We use a non-tag-transparent scope here, which causes pushtag to
699 put tags in this scope, rather than in the enclosing class or
700 namespace scope. This is the right thing, since we want
701 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
702 global template class, push_template_decl handles putting the
703 TEMPLATE_DECL into top-level scope. For a nested template class,
704 e.g.:
706 template <class T> struct S1 {
707 template <class T> struct S2 {};
708 };
710 pushtag contains special code to insert the TEMPLATE_DECL for S2
711 at the right scope. */
717 /* Add a dummy parameter level while we process the parameter list. */
718 current_template_parms
721 current_template_parms);
722 }
724 /* This routine is called when a specialization is declared. If it is
725 invalid to declare a specialization here, an error is reported and
726 false is returned, otherwise this routine will return true. */
728 static bool
730 {
733 /* [temp.expl.spec]
735 An explicit specialization shall be declared in the namespace of
736 which the template is a member, or, for member templates, in the
737 namespace of which the enclosing class or enclosing class
738 template is a member. An explicit specialization of a member
739 function, member class or static data member of a class template
740 shall be declared in the namespace of which the class template
741 is a member. */
743 {
746 }
748 /* [temp.expl.spec]
750 In an explicit specialization declaration for a member of a class
751 template or a member template that appears in namespace scope,
752 the member template and some of its enclosing class templates may
753 remain unspecialized, except that the declaration shall not
754 explicitly specialize a class member template if its enclosing
755 class templates are not explicitly specialized as well. */
757 {
760 }
763 }
765 /* We've just seen template <>. */
767 bool
769 {
773 }
775 /* Called at then end of processing a declaration preceded by
776 template<>. */
778 void
780 {
783 }
785 /* Any template <>'s that we have seen thus far are not referring to a
786 function specialization. */
788 void
790 {
793 }
795 /* We've just seen a template header. If SPECIALIZATION is nonzero,
796 it was of the form template <>. */
798 static void
800 {
802 template_header_count++;
803 }
805 /* We're beginning an explicit instantiation. */
807 void
809 {
812 }
815 void
817 {
820 }
822 /* An explicit specialization or partial specialization of TMPL is being
823 declared. Check that the namespace in which the specialization is
824 occurring is permissible. Returns false iff it is invalid to
825 specialize TMPL in the current namespace. */
827 static bool
829 {
832 /* [tmpl.expl.spec]
834 An explicit specialization shall be declared in a namespace enclosing the
835 specialized template. An explicit specialization whose declarator-id is
836 not qualified shall be declared in the nearest enclosing namespace of the
837 template, or, if the namespace is inline (7.3.1), any namespace from its
838 enclosing namespace set. */
841 {
844 }
847 /* Same or enclosing namespace. */
849 else
850 {
851 auto_diagnostic_group d;
857 }
858 }
860 /* SPEC is an explicit instantiation. Check that it is valid to
861 perform this explicit instantiation in the current namespace. */
863 static void
865 {
866 tree ns;
868 /* DR 275: An explicit instantiation shall appear in an enclosing
869 namespace of its template. */
875 }
877 /* Returns true if TYPE is a new partial specialization that needs to be
878 set up. This may also modify TYPE to point to the correct (new or
879 existing) constrained partial specialization. */
881 static bool
883 {
884 /* An implicit instantiation of an incomplete type implies
885 the definition of a new class template.
887 template<typename T>
888 struct S;
890 template<typename T>
891 struct S<T*>;
893 Here, S<T*> is an implicit instantiation of S whose type
894 is incomplete. */
898 /* It can also be the case that TYPE is a completed specialization.
899 Continuing the previous example, suppose we also declare:
901 template<typename T>
902 requires Integral<T>
903 struct S<T*>;
905 Here, S<T*> refers to the specialization S<T*> defined
906 above. However, we need to differentiate definitions because
907 we intend to define a new partial specialization. In this case,
908 we rely on the fact that the constraints are different for
909 this declaration than that above.
911 Note that we also get here for injected class names and
912 late-parsed template definitions. We must ensure that we
913 do not create new type declarations for those cases. */
915 {
919 /* If there are no template parameters, this cannot be a new
920 partial template specialization? */
924 /* The injected-class-name is not a new partial specialization. */
928 /* If the constraints are not the same as those of the primary
929 then, we can probably create a new specialization. */
933 {
937 }
939 /* Also, if there's a pre-existing specialization with matching
940 constraints, then this also isn't new. */
943 {
949 {
952 }
954 }
956 /* Create a new type node (and corresponding type decl)
957 for the newly declared specialization. */
962 /* We only need a separate type node for storing the definition of this
963 partial specialization; uses of S<T*> are unconstrained, so all are
964 equivalent. So keep TYPE_CANONICAL the same. */
967 /* Build the corresponding type decl. */
979 }
982 }
984 /* The TYPE is being declared. If it is a template type, that means it
985 is a partial specialization. Do appropriate error-checking. */
987 tree
989 {
990 tree context;
995 /* A lambda that appears in specialization context is not itself a
996 specialization. */
1000 /* An injected-class-name is not a specialization. */
1005 {
1009 }
1014 {
1020 else
1023 }
1025 {
1026 /* This is for ordinary explicit specialization and partial
1027 specialization of a template class such as:
1029 template <> class C<int>;
1031 or:
1033 template <class T> class C<T*>;
1035 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
1038 {
1045 {
1050 }
1051 }
1057 /* Trying to define a specialization either without a template<> header
1058 or in an inappropriate place. We've already given an error, so just
1059 bail now so we don't actually define the specialization. */
1061 }
1067 {
1068 /* This is for an explicit specialization of member class
1069 template according to [temp.expl.spec/18]:
1071 template <> template <class U> class C<int>::D;
1073 The context `C<int>' must be an implicit instantiation.
1074 Otherwise this is just a member class template declared
1075 earlier like:
1077 template <> class C<int> { template <class U> class D; };
1078 template <> template <class U> class C<int>::D;
1080 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1081 while in the second case, `C<int>::D' is a primary template
1082 and `C<T>::D' may not exist. */
1086 {
1087 tree t;
1092 {
1095 type))
1098 }
1100 /* Check for invalid specialization after instantiation:
1102 template <> template <> class C<int>::D<int>;
1103 template <> template <class U> class C<int>::D; */
1107 {
1111 {
1112 /* We already have a full specialization of this partial
1113 instantiation, or a full specialization has been
1114 looked up but not instantiated. Reassign it to the
1115 new member specialization template. */
1116 spec_entry elt;
1129 spec_entry **slot
1134 }
1135 else
1136 /* But if we've had an implicit instantiation, that's a
1137 problem ([temp.expl.spec]/6). */
1140 }
1142 /* Mark TYPE as a specialization. And as a result, we only
1143 have one level of template argument for the innermost
1144 class template. */
1149 }
1150 }
1152 {
1153 /* Someday C++0x may allow for enum template specialization. */
1158 else
1159 {
1162 }
1163 }
1166 }
1168 /* Returns nonzero if we can optimize the retrieval of specializations
1169 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1170 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1174 {
1177 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1178 parameter. */
1180 /* The optimized lookup depends on the fact that the
1181 template arguments for the member function template apply
1182 purely to the containing class, which is not true if the
1183 containing class is an explicit or partial
1184 specialization. */
1188 /* It is possible to have a template that is not a member
1189 template and is not a member of a template class:
1191 template <typename T>
1192 struct S { friend A::f(); };
1194 Here, the friend function is a template, but the context does
1195 not have template information. The optimized lookup relies
1196 on having ARGS be the template arguments for both the class
1197 and the function template. */
1199 }
1201 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1202 gone through coerce_template_parms by now. */
1204 static void
1206 {
1208 {
1217 /* Allow typedefs on the type of a non-type argument, since a
1219 else
1221 }
1222 }
1224 static void
1226 {
1231 }
1233 /* Retrieve the specialization (in the sense of [temp.spec] - a
1234 specialization is either an instantiation or an explicit
1235 specialization) of TMPL for the given template ARGS. If there is
1236 no such specialization, return NULL_TREE. The ARGS are a vector of
1237 arguments, or a vector of vectors of arguments, in the case of
1238 templates with more than one level of parameters.
1240 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1241 then we search for a partial specialization matching ARGS. This
1242 parameter is ignored if TMPL is not a class template.
1244 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1245 result is a NONTYPE_ARGUMENT_PACK. */
1247 static tree
1249 {
1259 /* There should be as many levels of arguments as there are
1260 levels of parameters. */
1269 /* Lambda functions in templates aren't instantiated normally, but through
1270 tsubst_lambda_expr. */
1275 {
1276 /* The template arguments actually apply to the containing
1277 class. Find the class specialization with those
1278 arguments. */
1280 tree class_specialization
1285 /* Find the instance of TMPL. */
1288 {
1292 /* using-declarations can bring in a different
1293 instantiation of tmpl as a member of a different
1294 instantiation of tmpl's class. We don't want those
1295 here. */
1298 }
1300 }
1301 else
1302 {
1304 spec_entry elt;
1313 else
1321 }
1324 }
1326 /* Like retrieve_specialization, but for local declarations. */
1328 tree
1330 {
1336 }
1338 /* Returns nonzero iff DECL is a specialization of TMPL. */
1340 int
1342 {
1343 tree t;
1346 {
1352 }
1353 else
1354 {
1363 }
1366 }
1368 /* Returns nonzero iff DECL is a specialization of friend declaration
1369 FRIEND_DECL according to [temp.friend]. */
1371 bool
1373 {
1380 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1381 of a template class, we want to check if DECL is a specialization
1382 if this. */
1386 {
1387 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1390 }
1395 /* There is nothing to do if this is not a template friend. */
1402 /* [temp.friend/6]
1403 A member of a class template may be declared to be a friend of a
1404 non-template class. In this case, the corresponding member of
1405 every specialization of the class template is a friend of the
1406 class granting friendship.
1408 For example, given a template friend declaration
1410 template <class T> friend void A<T>::f();
1412 the member function below is considered a friend
1414 template <> struct A<int> {
1415 void f();
1416 };
1418 For this type of template friend, TEMPLATE_DEPTH below will be
1419 nonzero. To determine if DECL is a friend of FRIEND, we first
1420 check if the enclosing class is a specialization of another. */
1427 {
1428 /* Next, we check the members themselves. In order to handle
1429 a few tricky cases, such as when FRIEND_DECL's are
1431 template <class T> friend void A<T>::g(T t);
1432 template <class T> template <T t> friend void A<T>::h();
1434 and DECL's are
1436 void A<int>::g(int);
1437 template <int> void A<int>::h();
1439 we need to figure out ARGS, the template arguments from
1440 the context of DECL. This is required for template substitution
1441 of `T' in the function parameter of `g' and template parameter
1442 of `h' in the above examples. Here ARGS corresponds to `int'. */
1449 {
1451 {
1454 else
1456 current_depth++;
1457 }
1459 }
1462 {
1464 tree friend_type;
1465 tree decl_type;
1466 tree friend_args_type;
1467 tree decl_args_type;
1469 /* Make sure that both DECL and FRIEND_DECL are templates or
1470 non-templates. */
1476 {
1477 /* If both are templates, check template parameter list. */
1478 tree friend_parms
1483 friend_parms))
1487 }
1488 else
1496 /* Check if return types match. */
1500 /* Check if function parameter types match, ignoring the
1501 `this' parameter. */
1510 }
1511 else
1512 {
1513 /* DECL is a TYPE_DECL */
1517 /* Make sure that both DECL and FRIEND_DECL are templates or
1518 non-templates. */
1519 is_template
1526 {
1527 tree friend_parms;
1528 /* If both are templates, check the name of the two
1529 TEMPLATE_DECL's first because is_friend didn't. */
1534 /* Now check template parameter list. */
1535 friend_parms
1538 return comp_template_parms
1540 friend_parms);
1541 }
1542 else
1545 }
1546 }
1548 }
1550 /* Register the specialization SPEC as a specialization of TMPL with
1551 the indicated ARGS. IS_FRIEND indicates whether the specialization
1552 is actually just a friend declaration. ATTRLIST is the list of
1553 attributes that the specialization is declared with or NULL when
1554 it isn't. Returns SPEC, or an equivalent prior declaration, if
1555 available.
1557 We also store instantiations of field packs in the hash table, even
1558 though they are not themselves templates, to make lookup easier. */
1560 static tree
1562 hashval_t hash)
1563 {
1564 tree fn;
1566 spec_entry elt;
1574 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1575 register it; we want the corresponding TEMPLATE_DECL instead.
1576 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1577 the more obvious `uses_template_parms (spec)' to avoid problems
1578 with default function arguments. In particular, given
1579 something like this:
1581 template <class T> void f(T t1, T t = T())
1583 the default argument expression is not substituted for in an
1584 instantiation unless and until it is actually needed. */
1588 /* We don't put these specializations in the hash table, but we might
1589 want to give an error about a mismatch. */
1591 else
1592 {
1603 else
1605 }
1607 /* We can sometimes try to re-register a specialization that we've
1608 already got. In particular, regenerate_decl_from_template calls
1609 duplicate_decls which will update the specialization list. But,
1610 we'll still get called again here anyhow. It's more convenient
1611 to simply allow this than to try to prevent it. */
1615 {
1617 {
1620 {
1622 fn);
1624 }
1625 else
1626 {
1627 tree clone;
1628 /* This situation should occur only if the first
1629 specialization is an implicit instantiation, the
1630 second is an explicit specialization, and the
1631 implicit instantiation has not yet been used. That
1632 situation can occur if we have implicitly
1633 instantiated a member function and then specialized
1634 it later.
1636 We can also wind up here if a friend declaration that
1637 looked like an instantiation turns out to be a
1638 specialization:
1640 template <class T> void foo(T);
1641 class S { friend void foo<>(int) };
1642 template <> void foo(int);
1644 We transform the existing DECL in place so that any
1645 pointers to it become pointers to the updated
1646 declaration.
1648 If there was a definition for the template, but not
1649 for the specialization, we want this to look as if
1650 there were no definition, and vice versa. */
1653 /* The call to duplicate_decls will have applied
1654 [temp.expl.spec]:
1656 An explicit specialization of a function template
1657 is inline only if it is explicitly declared to be,
1658 and independently of whether its function template
1659 is.
1661 to the primary function; now copy the inline bits to
1662 the various clones. */
1664 {
1671 }
1675 }
1676 }
1678 {
1681 /* We've already complained in duplicate_decls. */
1685 /* Dup decl failed, but this is a new definition. Set the
1686 line number so any errors match this new
1687 definition. */
1691 }
1692 }
1696 /* A specialization must be declared in the same namespace as the
1697 template it is specializing. */
1703 {
1712 /* If TMPL is a forward declaration of a template function, keep a list
1713 of all specializations in case we need to reassign them to a friend
1714 template later in tsubst_friend_function.
1716 Also keep a list of all variable template instantiations so that
1717 process_partial_specialization can check whether a later partial
1718 specialization would have used it. */
1721 }
1724 }
1726 /* Restricts tree and type comparisons. */
1730 /* Returns true iff two spec_entry nodes are equivalent. */
1732 bool
1734 {
1743 /* tmpl could be a FIELD_DECL for a capture pack. */
1747 {
1748 /* Partial specializations of a variable template can be distinguished by
1749 constraints. */
1753 }
1759 }
1761 /* Returns a hash for a template TMPL and template arguments ARGS. */
1763 static hashval_t
1765 {
1768 }
1770 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1771 ignoring SPEC. */
1773 hashval_t
1775 {
1777 }
1779 /* Recursively calculate a hash value for a template argument ARG, for use
1780 in the hash tables of template specializations. We must be
1781 careful to (at least) skip the same entities template_args_equal
1782 does. */
1784 hashval_t
1786 {
1791 /* Strip nop-like things, but not the same as STRIP_NOPS. */
1802 {
1804 /* Getting here with an ARGUMENT_PACK_SELECT means we're probably
1805 preserving it in a hash table, which is bad because it will change
1806 meaning when gen_elem_of_pack_expansion_instantiation changes the
1807 ARGUMENT_PACK_SELECT_INDEX. */
1841 {
1844 {
1847 }
1849 }
1853 {
1856 }
1867 val = iterative_hash_template_arg
1879 val);
1881 val);
1890 /* [temp.over.link] Two lambda-expressions are never considered
1891 equivalent.
1893 So just hash the closure type. */
1904 /* Now hash operands as usual. */
1908 {
1911 {
1915 }
1917 call_expr_arg_iterator ai;
1922 }
1926 }
1930 {
1933 {
1934 // We want an alias specialization that survived strip_typedefs
1935 // to hash differently from its TYPE_CANONICAL, to avoid hash
1936 // collisions that compare as different in template_args_equal.
1937 // These could be dependent specializations that strip_typedefs
1938 // left alone, or untouched specializations because
1939 // coerce_template_parms returns the unconverted template
1940 // arguments if it sees incomplete argument packs.
1943 }
1946 {
1948 {
1951 /* Do not recurse with TPI directly, as that is unbounded
1952 recursion. */
1955 }
1966 }
1979 }
1980 }
1982 /* Unregister the specialization SPEC as a specialization of TMPL.
1983 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1984 if the SPEC was listed as a specialization of TMPL.
1986 Note that SPEC has been ggc_freed, so we can't look inside it. */
1988 bool
1990 {
1992 spec_entry elt;
2000 {
2005 }
2008 }
2010 /* Like register_specialization, but for local declarations. We are
2011 registering SPEC, an instantiation of TMPL. */
2013 void
2015 {
2018 }
2020 /* TYPE is a class type. Returns true if TYPE is an explicitly
2021 specialized class. */
2023 bool
2025 {
2029 }
2031 /* Print the list of functions at FNS, going through all the overloads
2032 for each element of the list. Alternatively, FNS cannot be a
2033 TREE_LIST, in which case it will be printed together with all the
2034 overloads.
2036 MORE and *STR should respectively be FALSE and NULL when the function
2037 is called from the outside. They are used internally on recursive
2038 calls. print_candidates manages the two parameters and leaves NULL
2039 in *STR when it ends. */
2041 static void
2043 {
2047 else
2049 {
2055 {
2058 else
2061 }
2063 }
2064 }
2066 /* Print the list of candidate FNS in an error message. FNS can also
2067 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
2069 void
2071 {
2075 }
2077 /* Get a (possibly) constrained template declaration for the
2078 purpose of ordering candidates. */
2079 static tree
2081 {
2087 }
2089 /* Among candidates having the same signature, return the
2090 most constrained or NULL_TREE if there is no best candidate.
2091 If the signatures of candidates vary (e.g., template
2092 specialization vs. member function), then there can be no
2093 most constrained.
2095 Note that we don't compare constraints on the functions
2096 themselves, but rather those of their templates. */
2097 static tree
2099 {
2100 // Try to find the best candidate in a first pass.
2103 {
2110 }
2112 // Verify that the champ is better than previous candidates.
2117 }
2120 }
2123 /* Returns the template (one of the functions given by TEMPLATE_ID)
2124 which can be specialized to match the indicated DECL with the
2125 explicit template args given in TEMPLATE_ID. The DECL may be
2126 NULL_TREE if none is available. In that case, the functions in
2127 TEMPLATE_ID are non-members.
2129 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2130 specialization of a member template.
2132 The TEMPLATE_COUNT is the number of references to qualifying
2133 template classes that appeared in the name of the function. See
2134 check_explicit_specialization for a more accurate description.
2136 TSK indicates what kind of template declaration (if any) is being
2137 declared. TSK_TEMPLATE indicates that the declaration given by
2138 DECL, though a FUNCTION_DECL, has template parameters, and is
2139 therefore a template function.
2141 The template args (those explicitly specified and those deduced)
2142 are output in a newly created vector *TARGS_OUT.
2144 If it is impossible to determine the result, an error message is
2145 issued. The error_mark_node is returned to indicate failure. */
2147 static tree
2149 tree decl,
2153 tmpl_spec_kind tsk)
2154 {
2155 tree fns;
2156 tree targs;
2157 tree explicit_targs;
2160 /* A TREE_LIST of templates of which DECL may be a specialization.
2161 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2162 corresponding TREE_PURPOSE is the set of template arguments that,
2163 when used to instantiate the template, would produce a function
2164 with the signature of DECL. */
2174 /* We shouldn't be specializing a member template of an
2175 unspecialized class template; we already gave an error in
2176 check_specialization_scope, now avoid crashing. */
2180 {
2183 }
2191 /* Check for baselinks. */
2196 {
2200 }
2202 {
2205 }
2207 /* Count the number of template headers specified for this
2208 specialization. */
2219 {
2222 tf_warning_or_error,
2227 }
2229 {
2233 {
2234 tree decl_arg_types;
2235 tree fn_arg_types;
2237 /* In case of explicit specialization, we need to check if
2238 the number of template headers appearing in the specialization
2239 is correct. This is usually done in check_explicit_specialization,
2240 but the check done there cannot be exhaustive when specializing
2241 member functions. Consider the following code:
2243 template <> void A<int>::f(int);
2244 template <> template <> void A<int>::f(int);
2246 Assuming that A<int> is not itself an explicit specialization
2247 already, the first line specializes "f" which is a non-template
2248 member function, whilst the second line specializes "f" which
2249 is a template member function. So both lines are syntactically
2250 correct, and check_explicit_specialization does not reject
2251 them.
2253 Here, we can do better, as we are matching the specialization
2254 against the declarations. We count the number of template
2255 headers, and we check if they match TEMPLATE_COUNT + 1
2256 (TEMPLATE_COUNT is the number of qualifying template classes,
2257 plus there must be another header for the member template
2258 itself).
2260 Notice that if header_count is zero, this is not a
2261 specialization but rather a template instantiation, so there
2262 is no check we can perform here. */
2264 {
2267 }
2269 /* Check that the number of template arguments at the
2270 innermost level for DECL is the same as for FN. */
2278 /* DECL might be a specialization of FN. */
2282 /* For a non-static member function, we need to make sure
2283 that the const qualification is the same. Since
2284 get_bindings does not try to merge the "this" parameter,
2285 we must do the comparison explicitly. */
2287 {
2292 /* And the ref-qualification. */
2296 }
2298 /* Skip the "this" parameter and, for constructors of
2299 classes with virtual bases, the VTT parameter. A
2300 full specialization of a constructor will have a VTT
2301 parameter, but a template never will. */
2302 decl_arg_types
2304 fn_arg_types
2307 /* Function templates cannot be specializations; there are
2308 no partial specializations of functions. Therefore, if
2309 the type of DECL does not match FN, there is no
2310 match.
2312 Note that it should never be the case that we have both
2313 candidates added here, and for regular member functions
2314 below. */
2316 {
2318 current_template_parms))
2331 {
2332 /* C++20 CA104: Substitute directly into the
2333 constraint-expression. */
2339 }
2343 }
2345 /* See whether this function might be a specialization of this
2346 template. Suppress access control because we might be trying
2347 to make this specialization a friend, and we have already done
2348 access control for the declaration of the specialization. */
2354 /* We cannot deduce template arguments that when used to
2355 specialize TMPL will produce DECL. */
2359 /* We deduced something involving 'auto', which isn't a valid
2360 template argument. */
2363 /* Save this template, and the arguments deduced. */
2365 }
2367 /* FN is an ordinary member function, and we need a
2368 specialization of a member template. */
2369 ;
2371 /* We can get IDENTIFIER_NODEs here in certain erroneous
2372 cases. */
2373 ;
2375 /* This is just an ordinary non-member function. Nothing can
2376 be a specialization of that. */
2377 ;
2379 /* Cannot specialize functions that are created implicitly. */
2380 ;
2381 else
2382 {
2383 tree decl_arg_types;
2385 /* This is an ordinary member function. However, since
2386 we're here, we can assume its enclosing class is a
2387 template class. For example,
2389 template <typename T> struct S { void f(); };
2390 template <> void S<int>::f() {}
2392 Here, S<int>::f is a non-template, but S<int> is a
2393 template class. If FN has the same type as DECL, we
2394 might be in business. */
2397 /* Its enclosing class is an explicit specialization
2398 of a template class. This is not a candidate. */
2403 /* The return types differ. */
2406 /* Adjust the type of DECL in case FN is a static member. */
2413 decl_arg_types))
2421 // If the deduced arguments do not satisfy the constraints,
2422 // this is not a candidate.
2426 // Add the candidate.
2428 }
2429 }
2432 {
2433 /* We have:
2435 [temp.expl.spec]
2437 It is possible for a specialization with a given function
2438 signature to be instantiated from more than one function
2439 template. In such cases, explicit specification of the
2440 template arguments must be used to uniquely identify the
2441 function template specialization being specialized.
2443 Note that here, there's no suggestion that we're supposed to
2444 determine which of the candidate templates is most
2445 specialized. However, we, also have:
2447 [temp.func.order]
2449 Partial ordering of overloaded function template
2450 declarations is used in the following contexts to select
2451 the function template to which a function template
2452 specialization refers:
2454 -- when an explicit specialization refers to a function
2455 template.
2457 So, we do use the partial ordering rules, at least for now.
2458 This extension can only serve to make invalid programs valid,
2459 so it's safe. And, there is strong anecdotal evidence that
2460 the committee intended the partial ordering rules to apply;
2461 the EDG front end has that behavior, and John Spicer claims
2462 that the committee simply forgot to delete the wording in
2463 [temp.expl.spec]. */
2466 {
2469 }
2470 }
2472 // Concepts allows multiple declarations of member functions
2473 // with the same signature. Like above, we need to rely on
2474 // on the partial ordering of those candidates to determine which
2475 // is the best.
2477 {
2479 {
2482 }
2483 }
2486 {
2491 "saw %d %<template<>%>, need %d for "
2496 }
2500 {
2506 }
2508 /* We have one, and exactly one, match. */
2510 {
2514 /* Propagate the candidate's constraints to the declaration. */
2518 /* DECL is a re-declaration or partial instantiation of a template
2519 function. */
2522 /* It was a specialization of an ordinary member function in a
2523 template class. */
2525 }
2527 /* It was a specialization of a template. */
2530 {
2535 }
2536 else
2539 }
2541 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2542 but with the default argument values filled in from those in the
2543 TMPL_TYPES. */
2545 static tree
2547 tree tmpl_types)
2548 {
2549 tree new_spec_types;
2557 /* Substitute into the rest of the list. */
2558 new_spec_types =
2562 /* Add the default argument for this parameter. */
2565 new_spec_types);
2566 }
2568 /* DECL is an explicit specialization. Replicate default arguments
2569 from the template it specializes. (That way, code like:
2571 template <class T> void f(T = 3);
2572 template <> void f(double);
2573 void g () { f (); }
2575 works, as required.) An alternative approach would be to look up
2576 the correct default arguments at the call-site, but this approach
2577 is consistent with how implicit instantiations are handled. */
2579 static void
2581 {
2582 tree tmpl;
2583 tree spec_types;
2584 tree tmpl_types;
2585 tree new_spec_types;
2586 tree old_type;
2587 tree new_type;
2588 tree t;
2593 /* See if there's anything we need to do. */
2606 {
2607 /* Remove the this pointer, but remember the object's type for
2608 CV quals. */
2614 {
2615 /* DECL may contain more parameters than TMPL due to the extra
2616 in-charge parameter in constructors and destructors. */
2619 }
2621 {
2624 }
2625 }
2627 /* Compute the merged default arguments. */
2628 new_spec_types =
2631 /* Compute the new FUNCTION_TYPE. */
2633 {
2637 new_spec_types);
2640 /* Put the in-charge parameter back. */
2643 new_spec_types);
2647 new_spec_types);
2648 }
2649 else
2651 new_spec_types);
2657 }
2659 /* Return the number of template headers we expect to see for a definition
2660 or specialization of CTYPE or one of its non-template members. */
2662 int
2664 {
2668 {
2669 /* You're supposed to have one `template <...>' for every
2670 template class, but you don't need one for a full
2671 specialization. For example:
2673 template <class T> struct S{};
2674 template <> struct S<int> { void f(); };
2675 void S<int>::f () {}
2677 is correct; there shouldn't be a `template <>' for the
2678 definition of `S<int>::f'. */
2680 /* If CTYPE does not have template information of any
2681 kind, then it is not a template, nor is it nested
2682 within a template. */
2690 }
2693 }
2695 /* Do a simple sanity check on the template headers that precede the
2696 variable declaration DECL. */
2698 void
2700 {
2705 {
2708 "variable templates only available with "
2711 // Namespace-scope variable templates should have a template header.
2713 }
2715 {
2716 auto_diagnostic_group d;
2718 "too many template headers for %qD "
2724 "members of an explicitly specialized class are defined "
2726 }
2727 }
2729 /* An explicit specialization whose declarator-id or class-head-name is not
2730 qualified shall be declared in the nearest enclosing namespace of the
2731 template, or, if the namespace is inline (7.3.1), any namespace from its
2732 enclosing namespace set.
2734 If the name declared in the explicit instantiation is an unqualified name,
2735 the explicit instantiation shall appear in the namespace where its template
2736 is declared or, if that namespace is inline (7.3.1), any namespace from its
2737 enclosing namespace set. */
2739 void
2741 {
2746 {
2752 /* This was allowed in C++98, so only pedwarn. */
2754 "outside its namespace must use a nested-name-"
2756 }
2757 }
2759 /* Warn for a template specialization SPEC that is missing some of a set
2760 of function or type attributes that the template TEMPL is declared with.
2761 ATTRLIST is a list of additional attributes that SPEC should be taken
2762 to ultimately be declared with. */
2764 static void
2766 {
2770 /* Avoid warning if the difference between the primary and
2771 the specialization is not in one of the attributes below. */
2775 };
2777 /* Put together a list of the black listed attributes that the primary
2778 template is declared with that the specialization is not, in case
2779 it's not apparent from the most recent declaration of the primary. */
2780 pretty_printer str;
2787 auto_diagnostic_group d;
2790 spec))
2796 }
2798 /* Check to see if the function just declared, as indicated in
2799 DECLARATOR, and in DECL, is a specialization of a function
2800 template. We may also discover that the declaration is an explicit
2801 instantiation at this point.
2803 Returns DECL, or an equivalent declaration that should be used
2804 instead if all goes well. Issues an error message if something is
2805 amiss. Returns error_mark_node if the error is not easily
2806 recoverable.
2808 FLAGS is a bitmask consisting of the following flags:
2810 2: The function has a definition.
2811 4: The function is a friend.
2813 The TEMPLATE_COUNT is the number of references to qualifying
2814 template classes that appeared in the name of the function. For
2815 example, in
2817 template <class T> struct S { void f(); };
2818 void S<int>::f();
2820 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2821 classes are not counted in the TEMPLATE_COUNT, so that in
2823 template <class T> struct S {};
2824 template <> struct S<int> { void f(); }
2825 template <> void S<int>::f();
2827 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2828 invalid; there should be no template <>.)
2830 If the function is a specialization, it is marked as such via
2831 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2832 is set up correctly, and it is added to the list of specializations
2833 for that template. */
2835 tree
2837 tree decl,
2840 tree attrlist)
2841 {
2850 tmpl_spec_kind tsk;
2853 {
2856 else
2858 }
2859 else
2863 {
2866 {
2869 }
2873 {
2875 /* This could be something like:
2877 template <class T> void f(T);
2878 class S { friend void f<>(int); } */
2880 else
2881 {
2882 /* This case handles bogus declarations like template <>
2883 template <class T> void f<int>(); */
2887 declarator);
2889 }
2890 }
2894 /* The error has already been reported in
2895 check_specialization_scope. */
2901 /* Fall through. */
2914 decl);
2917 else
2921 /* Fall through. */
2927 /* In cases like template<> constexpr bool v = true;
2928 We'll give an error in check_template_variable. */
2934 else
2940 {
2941 /* This case handles bogus declarations like template <>
2942 template <class T> void f<int>(); */
2947 declarator);
2949 {
2950 /* Partial specialization of variable template. */
2954 }
2957 "non-type partial specialization %qE "
2959 else
2961 "non-class, non-variable partial specialization %qE "
2964 ok:;
2965 }
2968 /* This is a specialization of a member template, without
2969 specialization the containing class. Something like:
2971 template <class T> struct S {
2972 template <class U> void f (U);
2973 };
2974 template <> template <class U> void S<int>::f(U) {}
2976 That's a specialization -- but of the entire template. */
2982 }
2985 /* This doesn't apply to variable templates. */
2987 {
2991 {
2995 }
2996 }
2999 {
3005 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
3007 {
3008 tree fns;
3013 else
3014 {
3015 /* If there is no class context, the explicit instantiation
3016 must be at namespace scope. */
3019 /* Find the namespace binding, using the declaration
3020 context. */
3024 {
3025 /* If lookup fails, look for a friend declaration so we can
3026 give a better diagnostic. */
3027 fns = (lookup_qualified_name
3032 }
3035 {
3038 }
3039 }
3042 }
3048 {
3050 /* A specialization in class scope. This is invalid,
3051 but the error will already have been flagged by
3052 check_specialization_scope. */
3054 else
3055 {
3056 /* It's not valid to write an explicit instantiation in
3057 class scope, e.g.:
3059 class C { template void f(); }
3061 This case is caught by the parser. However, on
3062 something like:
3064 template class C { void f(); };
3066 (which is invalid) we can get here. The error will be
3067 issued later. */
3068 ;
3069 }
3072 }
3075 {
3076 // We'll match variable templates in start_decl.
3080 /* Find the list of functions in ctype that have the same
3081 name as the declared function. */
3085 {
3089 {
3090 /* From [temp.expl.spec]:
3092 If such an explicit specialization for the member
3093 of a class template names an implicitly-declared
3094 special member function (clause _special_), the
3095 program is ill-formed.
3097 Similar language is found in [temp.explicit]. */
3100 }
3103 }
3105 /* For a type-conversion operator, We might be looking for
3106 `operator int' which will be a specialization of
3107 `operator T'. Grab all the conversion operators, and
3108 then select from them. */
3113 {
3116 }
3117 else
3119 }
3121 /* Figure out what exactly is being specialized at this point.
3122 Note that for an explicit instantiation, even one for a
3123 member function, we cannot tell a priori whether the
3124 instantiation is for a member template, or just a member
3125 function of a template class. Even if a member template is
3126 being instantiated, the member template arguments may be
3127 elided if they can be deduced from the rest of the
3128 declaration. */
3131 member_specialization,
3132 template_count,
3133 tsk);
3136 /* We couldn't figure out what this declaration was
3137 specializing. */
3139 else
3140 {
3142 {
3143 auto_diagnostic_group d;
3145 "friend declaration %qD is not visible to "
3149 }
3158 {
3159 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3160 is done by do_decl_instantiation later. */
3166 {
3167 /* If TMPL is not the most general template (for
3168 example, if TMPL is a friend template that is
3169 injected into namespace scope), then there will
3170 be too many levels of TARGS. Remove some of them
3171 here. */
3173 tree new_targs;
3180 }
3183 }
3185 /* If we thought that the DECL was a member function, but it
3186 turns out to be specializing a static member function,
3187 make DECL a static member function as well. */
3193 /* If this is a specialization of a member template of a
3194 template class, we want to return the TEMPLATE_DECL, not
3195 the specialization of it. */
3197 {
3202 {
3203 tree parm;
3207 /* We want to use the argument list specified in the
3208 definition, not in the original declaration. */
3213 }
3216 }
3218 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3224 /* Inherit default function arguments from the template
3225 DECL is specializing. */
3229 /* This specialization has the same protection as the
3230 template it specializes. */
3234 /* 7.1.1-1 [dcl.stc]
3236 A storage-class-specifier shall not be specified in an
3237 explicit specialization...
3239 The parser rejects these, so unless action is taken here,
3240 explicit function specializations will always appear with
3241 global linkage.
3243 The action recommended by the C++ CWG in response to C++
3244 defect report 605 is to make the storage class and linkage
3245 of the explicit specialization match the templated function:
3247 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3248 */
3250 {
3254 /* A concept cannot be specialized. */
3256 {
3258 gen_tmpl);
3260 }
3262 /* This specialization has the same linkage and visibility as
3263 the function template it specializes. */
3266 {
3269 }
3272 {
3275 }
3276 }
3278 /* If DECL is a friend declaration, declared using an
3279 unqualified name, the namespace associated with DECL may
3280 have been set incorrectly. For example, in:
3282 template <typename T> void f(T);
3283 namespace N {
3284 struct S { friend void f<int>(int); }
3285 }
3287 we will have set the DECL_CONTEXT for the friend
3288 declaration to N, rather than to the global namespace. */
3293 /* This is not really a declaration of a specialization.
3294 It's just the name of an instantiation. But, it's not
3295 a request for an instantiation, either. */
3298 /* A specialization is not necessarily COMDAT. */
3304 /* If this is a full specialization, register it so that we can find
3305 it again. Partial specializations will be registered in
3306 process_partial_specialization. */
3308 {
3313 }
3316 /* A 'structor should already have clones. */
3322 }
3323 }
3326 }
3328 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3329 parameters. These are represented in the same format used for
3330 DECL_TEMPLATE_PARMS. */
3332 int
3334 {
3335 const_tree p1;
3336 const_tree p2;
3344 {
3356 {
3360 /* If either of the template parameters are invalid, assume
3361 they match for the sake of error recovery. */
3374 }
3375 }
3378 /* One set of parameters has more parameters lists than the
3379 other. */
3383 }
3385 /* Returns true if two template parameters are declared with
3386 equivalent constraints. */
3388 static bool
3390 {
3398 }
3400 /* Returns true when two template parameters are equivalent. */
3402 static bool
3404 {
3408 /* If either of the template parameters are invalid, assume
3409 they match for the sake of error recovery. */
3413 /* ... they declare parameters of the same kind. */
3417 /* ... one parameter was introduced by a parameter declaration, then
3418 both are. This case arises as a result of eagerly rewriting declarations
3419 during parsing. */
3423 /* ... if either declares a pack, they both do. */
3428 {
3429 /* ... if they declare non-type parameters, the types are equivalent. */
3432 }
3434 {
3435 /* ... if they declare template template parameters, their template
3436 parameter lists are equivalent. */
3439 }
3441 /* ... if they are declared with a qualified-concept name, they both
3442 are, and those names are equivalent. */
3444 }
3446 /* Returns true if two template parameters lists are equivalent.
3447 Two template parameter lists are equivalent if they have the
3448 same length and their corresponding parameters are equivalent.
3450 PARMS1 and PARMS2 are TREE_LISTs containing TREE_VECs: the
3451 data structure returned by DECL_TEMPLATE_PARMS.
3453 This is generally the same implementation as comp_template_parms
3454 except that it also the concept names and arguments used to
3455 introduce parameters. */
3457 static bool
3459 {
3466 {
3474 {
3479 }
3483 }
3489 }
3491 /* Return true if the requires-clause of the template parameter lists are
3492 equivalent and false otherwise. */
3493 static bool
3495 {
3503 }
3505 /* Returns true if two template heads are equivalent. 17.6.6.1p6:
3506 Two template heads are equivalent if their template parameter
3507 lists are equivalent and their requires clauses are equivalent.
3509 In pre-C++20, this is equivalent to calling comp_template_parms
3510 for the template parameters of TMPL1 and TMPL2. */
3512 bool
3514 {
3518 /* Don't change the matching rules for pre-C++20. */
3522 /* ... have the same number of template parameters, and their
3523 corresponding parameters are equivalent. */
3527 /* ... if either has a requires-clause, they both do and their
3528 corresponding constraint-expressions are equivalent. */
3530 }
3532 /* Determine whether PARM is a parameter pack. */
3534 bool
3536 {
3537 /* Determine if we have a non-type template parameter pack. */
3544 /* If this is a list of template parameters, we could get a
3545 TYPE_DECL or a TEMPLATE_DECL. */
3549 /* Otherwise it must be a type template parameter. */
3553 }
3555 /* Determine if T is a function parameter pack. */
3557 bool
3559 {
3563 }
3565 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3566 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3568 tree
3570 {
3577 }
3579 /* Return true iff the function parameter PARAM_DECL was expanded
3580 from the function parameter pack PACK. */
3582 bool
3584 {
3589 /* The parameter pack and its pack arguments have the same
3590 DECL_PARM_INDEX. */
3592 }
3594 /* Determine whether ARGS describes a variadic template args list,
3595 i.e., one that is terminated by a template argument pack. */
3597 static bool
3599 {
3601 tree last_parm;
3615 }
3617 /* Generate a new name for the parameter pack name NAME (an
3618 IDENTIFIER_NODE) that incorporates its */
3620 static tree
3622 {
3623 /* Munge the name to include the parameter index. */
3624 #define NUMBUF_LEN 128
3638 }
3640 /* Return true if T is a primary function, class or alias template
3641 specialization, not including the template pattern. */
3643 bool
3645 {
3661 }
3663 /* Return true if PARM is a template template parameter. */
3665 bool
3667 {
3669 }
3671 /* Return true iff PARM is a DECL representing a type template
3672 parameter. */
3674 bool
3676 {
3681 }
3683 /* Return the template parameters of T if T is a
3684 primary template instantiation, NULL otherwise. */
3686 tree
3688 {
3693 parms = INNERMOST_TEMPLATE_PARMS
3697 }
3699 /* Returns the template arguments of T if T is a template instantiation,
3700 NULL otherwise. */
3702 tree
3704 {
3712 }
3714 /* Return the argument pack elements of T if T is a template argument pack,
3715 NULL otherwise. */
3717 tree
3719 {
3725 }
3727 /* In an ARGUMENT_PACK_SELECT, the actual underlying argument that the
3728 ARGUMENT_PACK_SELECT represents. */
3730 static tree
3732 {
3736 /* If the selected argument is an expansion E, that most likely means we were
3737 called from gen_elem_of_pack_expansion_instantiation during the
3738 substituting of an argument pack (of which the Ith element is a pack
3739 expansion, where I is ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
3740 In this case, the Ith element resulting from this substituting is going to
3741 be a pack expansion, which pattern is the pattern of E. Let's return the
3742 pattern of E, and gen_elem_of_pack_expansion_instantiation will build the
3743 resulting pack expansion from it. */
3745 {
3746 /* Make sure we aren't throwing away arg info. */
3749 }
3752 }
3754 /* Return a modification of ARGS that's suitable for preserving inside a hash
3755 table. In particular, this replaces each ARGUMENT_PACK_SELECT with its
3756 underlying argument. ARGS is copied (upon modification) iff COW_P. */
3758 static tree
3760 {
3765 {
3767 tree r;
3774 else
3777 {
3779 {
3782 }
3784 }
3785 }
3788 }
3790 /* True iff FN is a function representing a built-in variadic parameter
3791 pack. */
3793 bool
3795 {
3805 }
3807 /* True iff CALL is a call to a function representing a built-in variadic
3808 parameter pack. */
3810 static bool
3812 {
3816 }
3818 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3820 static tree
3822 tree in_decl)
3823 {
3829 {
3831 {
3834 }
3839 }
3840 else
3841 {
3846 /* Calculate the largest value of len that won't make the size of the vec
3847 overflow an int. The compiler will exceed resource limits long before
3848 this, but it seems a decent place to diagnose. */
3852 {
3856 max);
3858 }
3866 }
3867 }
3869 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3870 CALL. */
3872 static tree
3874 tree in_decl)
3875 {
3885 }
3887 /* Return true if the tree T has the extra args mechanism for
3888 avoiding partial instantiation. */
3890 static bool
3892 {
3897 }
3899 /* Structure used to track the progress of find_parameter_packs_r. */
3900 struct find_parameter_pack_data
3901 {
3902 /* TREE_LIST that will contain all of the parameter packs found by
3903 the traversal. */
3906 /* Set of AST nodes that have been visited by the traversal. */
3909 /* True iff we're making a type pack expansion. */
3912 /* True iff we found a subtree that has the extra args mechanism. */
3914 };
3916 /* Identifies all of the argument packs that occur in a template
3917 argument and appends them to the TREE_LIST inside DATA, which is a
3918 find_parameter_pack_data structure. This is a subroutine of
3919 make_pack_expansion and uses_parameter_packs. */
3920 static tree
3922 {
3928 #define WALK_SUBTREE(NODE) \
3929 cp_walk_tree (&(NODE), &find_parameter_packs_r, \
3930 ppd, ppd->visited) \
3932 /* Don't look through typedefs; we are interested in whether a
3933 parameter pack is actually written in the expression/type we're
3934 looking at, not the target type. */
3936 {
3937 /* But do look at arguments for an alias template. */
3944 }
3946 /* Identify whether this is a parameter pack or not. */
3948 {
3956 /* FALLTHRU */
3958 /* If the placeholder appears in the decl-specifier-seq of a function
3959 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3960 is a pack expansion, the invented template parameter is a template
3961 parameter pack. */
3971 {
3972 /* We don't want to walk into the type of a PARM_DECL,
3973 because we don't want to see the type parameter pack. */
3976 }
3981 {
3982 /* We don't want to walk into the type of a variadic capture proxy,
3983 because we don't want to see the type parameter pack. */
3986 }
3988 {
3990 find_parameter_packs_r,
3993 }
4005 /* Not a parameter pack. */
4007 }
4010 {
4011 /* Add this parameter pack to the list. */
4013 }
4022 /* This switch statement will return immediately if we don't find a
4023 parameter pack. ??? Should some of these be in cp_walk_subtrees? */
4025 {
4027 /* Check the template itself. */
4033 {
4035 /* Ignore the declaration of a capture proxy for a parameter pack. */
4039 /* Since we stop at typedefs above, we need to look through them at
4040 the point of the DECL_EXPR. */
4044 }
4071 {
4072 /* Since we defer implicit capture, look in the parms and body. */
4079 }
4082 {
4083 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
4084 type_pack_expansion_p to false so that any placeholders
4085 within the expression don't get marked as parameter packs. */
4093 }
4102 /* Don't walk into IF_STMT_EXTRA_ARGS. */
4109 /* Local class, need to look through the whole definition. */
4113 else
4114 /* Enum, look at the values. */
4128 }
4130 #undef WALK_SUBTREE
4133 }
4135 /* Determines if the expression or type T uses any parameter packs. */
4136 tree
4138 {
4147 }
4149 /* Turn ARG, which may be an expression, type, or a TREE_LIST
4150 representation a base-class initializer into a parameter pack
4151 expansion. If all goes well, the resulting node will be an
4152 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
4153 respectively. */
4154 tree
4156 {
4157 tree result;
4166 {
4167 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
4168 class initializer. In this case, the TREE_PURPOSE will be a
4169 _TYPE node (representing the base class expansion we're
4170 initializing) and the TREE_VALUE will be a TREE_LIST
4171 containing the initialization arguments.
4173 The resulting expansion looks somewhat different from most
4174 expansions. Rather than returning just one _EXPANSION, we
4175 return a TREE_LIST whose TREE_PURPOSE is a
4176 TYPE_PACK_EXPANSION containing the bases that will be
4177 initialized. The TREE_VALUE will be identical to the
4178 original TREE_VALUE, which is a list of arguments that will
4179 be passed to each base. We do not introduce any new pack
4180 expansion nodes into the TREE_VALUE (although it is possible
4181 that some already exist), because the TREE_PURPOSE and
4182 TREE_VALUE all need to be expanded together with the same
4183 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
4184 resulting TREE_PURPOSE will mention the parameter packs in
4185 both the bases and the arguments to the bases. */
4186 tree purpose;
4187 tree value;
4190 /* Determine which parameter packs will be used by the base
4191 class expansion. */
4200 {
4203 arg);
4206 }
4209 {
4210 /* Collect the sets of parameter packs used in each of the
4211 initialization arguments. */
4213 {
4214 /* Determine which parameter packs will be expanded in this
4215 argument. */
4218 }
4219 }
4223 /* Create the pack expansion type for the base type. */
4229 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4230 they will rarely be compared to anything. */
4234 }
4239 /* Build the PACK_EXPANSION_* node. */
4240 result = for_types
4245 {
4246 /* Propagate type and const-expression information. */
4249 /* Mark this read now, since the expansion might be length 0. */
4251 }
4252 else
4253 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4254 they will rarely be compared to anything. */
4257 /* Determine which parameter packs will be expanded. */
4264 /* Make sure we found some parameter packs. */
4266 {
4268 {
4271 else
4273 }
4275 }
4280 /* If the pattern of this pack expansion contains a subtree that has
4281 the extra args mechanism for avoiding partial instantiation, then
4282 force this pack expansion to also use extra args. Otherwise
4283 partial instantiation of this pack expansion may not lower the
4284 level of some parameter packs within the pattern, which would
4285 confuse tsubst_pack_expansion later (PR101764). */
4289 }
4291 /* Checks T for any "bare" parameter packs, which have not yet been
4292 expanded, and issues an error if any are found. This operation can
4293 only be done on full expressions or types (e.g., an expression
4294 statement, "if" condition, etc.), because we could have expressions like:
4296 foo(f(g(h(args)))...)
4298 where "args" is a parameter pack. check_for_bare_parameter_packs
4299 should not be called for the subexpressions args, h(args),
4300 g(h(args)), or f(g(h(args))), because we would produce erroneous
4301 error messages.
4303 Returns TRUE and emits an error if there were bare parameter packs,
4304 returns FALSE otherwise. */
4305 bool
4307 {
4329 /* It's OK for a lambda to have an unexpanded parameter pack from the
4330 containing context, but do complain about unexpanded capture packs. */
4336 {
4337 /* We're in a lambda, but it isn't the innermost class.
4338 This should work, but currently doesn't. */
4341 }
4346 {
4352 }
4355 {
4358 {
4369 else
4374 else
4378 }
4381 }
4384 }
4386 /* Expand any parameter packs that occur in the template arguments in
4387 ARGS. */
4388 tree
4390 {
4399 /* First, determine if we need to expand anything, and the number of
4400 slots we'll need. */
4402 {
4407 {
4411 else
4413 }
4414 else
4415 {
4417 num_result_args++;
4418 }
4419 }
4421 /* If no expansion is necessary, we're done. */
4425 /* Expand arguments. */
4428 non_default_args_count =
4431 {
4434 {
4441 }
4442 else
4443 {
4446 }
4447 }
4451 }
4453 /* Checks if DECL shadows a template parameter.
4455 [temp.local]: A template-parameter shall not be redeclared within its
4456 scope (including nested scopes).
4458 Emits an error and returns TRUE if the DECL shadows a parameter,
4459 returns FALSE otherwise. */
4461 bool
4463 {
4464 tree olddecl;
4466 /* If we're not in a template, we can't possibly shadow a template
4467 parameter. */
4471 /* Figure out what we're shadowing. */
4475 /* If there's no previous binding for this name, we're not shadowing
4476 anything, let alone a template parameter. */
4480 /* If we're not shadowing a template parameter, we're done. Note
4481 that OLDDECL might be an OVERLOAD (or perhaps even an
4482 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4483 node. */
4487 /* We check for decl != olddecl to avoid bogus errors for using a
4488 name inside a class. We check TPFI to avoid duplicate errors for
4489 inline member templates. */
4495 /* Don't complain about the injected class name, as we've already
4496 complained about the class itself. */
4503 else
4508 }
4510 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4511 ORIG_LEVEL, DECL, and TYPE. */
4513 static tree
4517 tree decl,
4518 tree type)
4519 {
4530 }
4533 {
4535 {
4543 }
4546 {
4548 }
4549 };
4553 /* Find the canonical type parameter for the given template type
4554 parameter. Returns the canonical type parameter, which may be TYPE
4555 if no such parameter existed. */
4557 tree
4559 {
4567 }
4569 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4570 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4571 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4572 new one is created. */
4574 static tree
4576 tsubst_flags_t complain)
4577 {
4582 {
4587 type);
4602 /* Template template parameters need this. */
4605 {
4612 }
4614 /* Attach the TPI to the decl. */
4617 else
4619 }
4622 }
4624 /* Process information from new template parameter PARM and append it
4625 to the LIST being built. This new parameter is a non-type
4626 parameter iff IS_NON_TYPE is true. This new parameter is a
4627 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4628 is in PARM_LOC. */
4630 tree
4633 {
4639 {
4649 }
4656 {
4662 {
4663 /* [temp.param]
4665 The top-level cv-qualifiers on the template-parameter are
4666 ignored when determining its type. */
4671 && !is_parameter_pack
4672 /* If we're in a nested template parameter list, the template
4673 template parameter could be a parameter pack. */
4675 {
4676 /* This template parameter is not a parameter pack, but it
4677 should be. Complain about "bare" parameter packs. */
4680 /* Recover by calling this a parameter pack. */
4682 }
4683 }
4685 /* A template parameter is not modifiable. */
4694 current_template_depth,
4699 }
4700 else
4701 {
4702 tree t;
4706 {
4708 /* This is for distinguishing between real templates and template
4709 template parameters */
4712 /* any_template_parm_r expects to be able to get the targs of a
4713 DECL_TEMPLATE_RESULT. */
4722 }
4723 else
4724 {
4726 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4729 }
4736 current_template_depth,
4740 }
4744 /* Build requirements for the type/template parameter.
4745 This must be done after SET_DECL_TEMPLATE_PARM_P or
4746 process_template_parm could fail. */
4753 /* Build the parameter node linking the parameter declaration,
4754 its default argument (if any), and its constraints (if any). */
4760 else
4764 }
4766 /* The end of a template parameter list has been reached. Process the
4767 tree list into a parameter vector, converting each parameter into a more
4768 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4769 as PARM_DECLs. */
4771 tree
4773 {
4776 /* Pop the dummy parameter level and add the real one. We do not
4777 morph the dummy parameter in place, as it might have been
4778 captured by a (nested) template-template-parm. */
4781 current_template_parms
4786 {
4792 }
4797 }
4799 // Explicitly indicate the end of the template parameter list. We assume
4800 // that the current template parameters have been constructed and/or
4801 // managed explicitly, as when creating new template template parameters
4802 // from a shorthand constraint.
4803 void
4805 {
4807 }
4809 /* end_template_decl is called after a template declaration is seen. */
4811 void
4813 {
4819 /* This matches the pushlevel in begin_template_parm_list. */
4824 }
4826 /* Takes a TEMPLATE_PARM_P or DECL_TEMPLATE_PARM_P node or a TREE_LIST
4827 thereof, and converts it into an argument suitable to be passed to
4828 the type substitution functions. Note that if the TREE_LIST contains
4829 an error_mark node, the returned argument is error_mark_node. */
4831 tree
4833 {
4844 {
4848 else
4850 }
4856 {
4858 {
4859 /* Turn this argument into a TYPE_ARGUMENT_PACK
4860 with a single element, which expands T. */
4869 }
4870 }
4871 else
4872 {
4874 {
4875 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4876 with a single element, which expands T. */
4886 }
4887 else
4889 }
4891 }
4893 /* Given a single level of template parameters (a TREE_VEC), return it
4894 as a set of template arguments. */
4896 tree
4898 {
4908 }
4910 /* Given a set of template parameters, return them as a set of template
4911 arguments. The template parameters are represented as a TREE_VEC, in
4912 the form documented in cp-tree.h for template arguments. */
4914 tree
4916 {
4917 tree header;
4922 /* If there is only one level of template parameters, we do not
4923 create a TREE_VEC of TREE_VECs. Instead, we return a single
4924 TREE_VEC containing the arguments. */
4929 {
4934 else
4936 }
4939 }
4941 /* Within the declaration of a template, return the currently active
4942 template parameters as an argument TREE_VEC. */
4944 static tree
4946 {
4948 }
4950 /* Return the fully generic arguments for of TMPL, i.e. what
4951 current_template_args would be while parsing it. */
4953 tree
4955 {
4960 /* DECL_TEMPLATE_RESULT doesn't have the arguments we want. For a template
4961 template parameter, it has no TEMPLATE_INFO; for a partial
4962 specialization, it has the arguments for the primary template, and we
4968 }
4970 /* Update the declared TYPE by doing any lookups which were thought to be
4971 dependent, but are not now that we know the SCOPE of the declarator. */
4973 tree
4975 {
4986 /* Don't bother building up the args in this case. */
4988 {
4989 /* tsubst in the args corresponding to the template parameters,
4990 including auto if present. Most things will be unchanged, but
4991 make_typename_type and tsubst_qualified_id will resolve
4992 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4995 tree pushed;
4997 {
5001 }
5006 }
5012 {
5015 else
5017 }
5019 }
5021 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
5022 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
5023 the new template is a member template. */
5025 static tree
5027 {
5039 /* Propagate module information from the decl. */
5043 }
5045 struct template_parm_data
5046 {
5047 /* The level of the template parameters we are currently
5048 processing. */
5051 /* The index of the specialization argument we are currently
5052 processing. */
5055 /* An array whose size is the number of template parameters. The
5056 elements are nonzero if the parameter has been used in any one
5057 of the arguments processed so far. */
5060 /* An array whose size is the number of template arguments. The
5061 elements are nonzero if the argument makes use of template
5062 parameters of this level. */
5064 };
5066 /* Subroutine of push_template_decl used to see if each template
5067 parameter in a partial specialization is used in the explicit
5068 argument list. If T is of the LEVEL given in DATA (which is
5069 treated as a template_parm_data*), then DATA->PARMS is marked
5070 appropriately. */
5072 static int
5074 {
5082 {
5085 }
5087 /* In C++17 the type of a non-type argument is a deduced context. */
5092 data,
5093 NULL,
5096 /* Return zero so that for_each_template_parm will continue the
5097 traversal of the tree; we want to mark *every* template parm. */
5099 }
5101 /* Process the partial specialization DECL. */
5103 static tree
5105 {
5112 tree inner_parms;
5113 tree inst;
5123 /* A concept cannot be specialized. */
5125 {
5128 }
5133 /* We check that each of the template parameters given in the
5134 partial specialization is used in the argument list to the
5135 specialization. For example:
5137 template <class T> struct S;
5138 template <class T> struct S<T*>;
5140 The second declaration is OK because `T*' uses the template
5141 parameter T, whereas
5143 template <class T> struct S<int>;
5145 is no good. Even trickier is:
5147 template <class T>
5148 struct S1
5149 {
5150 template <class U>
5151 struct S2;
5152 template <class U>
5153 struct S2<T>;
5154 };
5156 The S2<T> declaration is actually invalid; it is a
5157 full-specialization. Of course,
5159 template <class U>
5160 struct S2<T (*)(U)>;
5162 or some such would have been OK. */
5170 {
5175 NULL,
5177 }
5180 {
5181 /* One of the template parms was not used in a deduced context in the
5182 specialization. */
5184 {
5188 }
5192 }
5197 /* [temp.class.spec]
5199 The argument list of the specialization shall not be identical to
5200 the implicit argument list of the primary template. */
5201 tree main_args
5204 && (!flag_concepts
5206 {
5209 "any template arguments; to define the primary template, "
5211 else
5213 "template arguments and is not more constrained than "
5214 "the primary template; to define the primary template, "
5217 }
5219 /* A partial specialization that replaces multiple parameters of the
5220 primary template with a pack expansion is less specialized for those
5221 parameters. */
5223 {
5225 "primary template because it replaces multiple parameters "
5228 /* Avoid crash in process_partial_specialization. */
5230 }
5233 {
5236 /* Avoid crash below. */
5238 }
5240 /* If we aren't in a dependent class, we can actually try deduction. */
5242 /* FIXME we should be able to handle a partial specialization of a
5243 partial instantiation, but currently we can't (c++/41727). */
5246 {
5247 auto_diagnostic_group d;
5250 decl))
5252 maintmpl);
5253 }
5255 /* [temp.spec.partial]
5257 The type of a template parameter corresponding to a specialized
5258 non-type argument shall not be dependent on a parameter of the
5259 specialization.
5261 Also, we verify that pack expansions only occur at the
5262 end of the argument list. */
5265 {
5272 {
5273 /* Extract the arguments from the argument pack. We'll be
5274 iterating over these in the following loop. */
5277 }
5280 {
5282 /* Get the Jth argument in the parameter pack. */
5286 {
5287 /* Pack expansions must come at the end of the
5288 argument list. */
5291 {
5295 else
5298 }
5299 }
5302 /* We only care about the pattern. */
5308 /* This next two lines are the `argument expression is not just a
5309 simple identifier' condition and also the `specialized
5310 non-type argument' bit. */
5315 {
5316 /* Look at the corresponding template parameter,
5317 marking which template parameters its type depends
5318 upon. */
5322 {
5323 /* We haven't yet initialized TPD2. Do so now. */
5325 /* The number of parameters here is the number in the
5326 main template, which, as checked in the assertion
5327 above, is NARGS. */
5331 }
5333 /* Mark the template parameters. But this time, we're
5334 looking for the template parameters of the main
5335 template, not in the specialization. */
5342 NULL,
5346 {
5347 /* The type depended on some template parameters.
5348 If they are fully specialized in the
5349 specialization, that's OK. */
5358 "type %qT of template argument %qE depends "
5360 "type %qT of template argument %qE depends "
5362 type,
5363 arg);
5364 }
5365 }
5366 }
5367 }
5369 /* We should only get here once. */
5373 // Build the template decl.
5380 /* Give template template parms a DECL_CONTEXT of the template
5381 for which they are a parameter. */
5383 {
5387 }
5390 /* We didn't register this in check_explicit_specialization so we could
5391 wait until the constraints were set. */
5393 else
5403 {
5409 {
5417 "declaration of %qD ambiguates earlier template "
5421 "partial specialization of %qD after instantiation "
5423 }
5424 }
5427 }
5429 /* PARM is a template parameter of some form; return the corresponding
5430 TEMPLATE_PARM_INDEX. */
5432 static tree
5434 {
5447 }
5449 /* Subroutine of fixed_parameter_pack_p below. Look for any template
5450 parameter packs used by the template parameter PARM. */
5452 static void
5454 {
5455 /* A type parm can't refer to another parm. */
5459 {
5463 }
5469 {
5473 else
5475 }
5476 }
5478 /* PARM is a template parameter pack. Return any parameter packs used in
5479 its type or the type of any of its template parameters. If there are
5480 any such packs, it will be instantiated into a fixed template parameter
5481 list by partial instantiation rather than be fully deduced. */
5483 tree
5485 {
5486 /* This can only be true in a member template. */
5489 /* This can only be true for a parameter pack. */
5492 /* A type parm can't refer to another parm. */
5506 }
5508 /* Check that a template declaration's use of default arguments and
5509 parameter packs is not invalid. Here, PARMS are the template
5510 parameters. IS_PRIMARY is true if DECL is the thing declared by
5511 a primary template. IS_PARTIAL is true if DECL is a partial
5512 specialization.
5514 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
5515 function template declaration or a friend class template
5516 declaration. In the function case, 1 indicates a declaration, 2
5517 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
5518 emitted for extraneous default arguments.
5520 Returns TRUE if there were no errors found, FALSE otherwise. */
5522 bool
5525 {
5528 tree parm_level;
5531 /* [temp.param]
5533 A default template-argument shall not be specified in a
5534 function template declaration or a function template definition, nor
5535 in the template-parameter-list of the definition of a member of a
5536 class template. */
5540 /* You can't have a function template declaration in a local
5541 scope, nor you can you define a member of a class template in a
5542 local scope. */
5550 /* A lambda doesn't have an explicit declaration; don't complain
5551 about the parms of the enclosing class. */
5558 /* If this is either a friend defined in the scope of the class
5559 or a member function. */
5565 /* And, if it was a member function, it really was defined in
5566 the scope of the class. */
5569 /* We already checked these parameters when the template was
5570 declared, so there's no need to do it again now. This function
5571 was defined in class scope, but we're processing its body now
5572 that the class is complete. */
5575 /* Core issue 226 (C++0x only): the following only applies to class
5576 templates. */
5579 {
5580 /* [temp.param]
5582 If a template-parameter has a default template-argument, all
5583 subsequent template-parameters shall have a default
5584 template-argument supplied. */
5586 {
5593 {
5603 {
5605 /* For better subsequent error-recovery, we indicate that
5606 there should have been a default argument. */
5609 }
5611 && !is_friend_decl
5612 /* Don't complain about an enclosing partial
5613 specialization. */
5618 /* A fixed parameter pack will be partially
5619 instantiated into a fixed length list. */
5621 {
5622 /* A primary class template, primary variable template
5623 (DR 2032), or alias template can only have one
5624 parameter pack, at the end of the template
5625 parameter list. */
5633 }
5634 }
5635 }
5636 }
5639 || is_partial
5640 || !is_primary
5642 /* For an ordinary class template, default template arguments are
5643 allowed at the innermost level, e.g.:
5644 template <class T = int>
5645 struct S {};
5646 but, in a partial specialization, they're not allowed even
5647 there, as we have in [temp.class.spec]:
5649 The template parameter list of a specialization shall not
5650 contain default template argument values.
5652 So, for a partial specialization, or for a function template
5653 (in C++98/C++03), we look at all of them. */
5654 ;
5655 else
5656 /* But, for a primary class template that is not a partial
5657 specialization we look at all template parameters except the
5658 innermost ones. */
5661 /* Figure out what error message to issue. */
5676 else
5677 /* Per [temp.param]/9, "A default template-argument shall not be
5678 specified in the template-parameter-lists of the definition of
5679 a member of a class template that appears outside of the member's
5680 class.", thus if we aren't handling a member of a class template
5681 there is no need to examine the parameters. */
5685 /* If we're inside a class definition, there's no need to
5686 examine the parameters to the class itself. On the one
5687 hand, they will be checked when the class is defined, and,
5688 on the other, default arguments are valid in things like:
5689 template <class T = double>
5690 struct S { template <class U> void f(U); };
5691 Here the default argument for `S' has no bearing on the
5692 declaration of `f'. */
5694 else
5695 /* Check everything. */
5701 {
5708 {
5713 {
5715 {
5722 }
5724 /* Clear out the default argument so that we are not
5725 confused later. */
5727 }
5728 }
5730 /* At this point, if we're still interested in issuing messages,
5731 they must apply to classes surrounding the object declared. */
5735 }
5738 }
5740 /* Worker for push_template_decl_real, called via
5741 for_each_template_parm. DATA is really an int, indicating the
5742 level of the parameters we are interested in. If T is a template
5743 parameter of that level, return nonzero. */
5745 static int
5747 {
5753 else
5756 }
5758 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5759 DATA is really an int, indicating the innermost outer level of parameters.
5760 If T is a template parameter of that level or further out, return
5761 nonzero. */
5763 static int
5765 {
5771 else
5774 }
5776 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5777 parameters given by current_template_args, or reuses a
5778 previously existing one, if appropriate. Returns the DECL, or an
5779 equivalent one, if it is replaced via a call to duplicate_decls.
5781 If IS_FRIEND is true, DECL is a friend declaration. */
5783 tree
5785 {
5789 /* See if this is a partial specialization. */
5798 /* No surprising friend functions. */
5803 tree ctx;
5805 /* For a friend, we want the context of the friend, not
5806 the type of which it is a friend. */
5810 /* In the case of a virtual function, we want the class in which
5811 it is defined. */
5813 else
5814 /* Otherwise, if we're currently defining some class, the DECL
5815 is assumed to be a member of the class. */
5824 /* See if this is a primary template. */
5828 /* A friend template that specifies a class context, i.e.
5829 template <typename T> friend void A<T>::f();
5830 is not primary. */
5831 ;
5833 /* Lambdas are not primary. */
5834 ;
5835 else
5838 /* True if the template is a member template, in the sense of
5839 [temp.mem]. */
5843 {
5851 {
5854 }
5856 {
5858 {
5861 }
5863 {
5864 /* [temp.mem]
5866 A destructor shall not be a member template. */
5870 }
5877 {
5878 /* [basic.stc.dynamic.allocation]
5880 An allocation function can be a function
5881 template. ... Template allocation functions shall
5882 have two or more parameters. */
5885 }
5886 }
5892 /* alias-declaration */
5898 else
5899 {
5902 }
5903 }
5910 /* Check to see that the rules regarding the use of default
5911 arguments are not being violated. We check args for a friend
5912 functions when we know whether it's a definition, introducing
5913 declaration or re-declaration. */
5918 /* Ensure that there are no parameter packs in the type of this
5919 declaration that have not been expanded. */
5921 {
5922 /* Check each of the arguments individually to see if there are
5923 any bare parameter packs. */
5929 {
5932 {
5933 /* This is a PARM_DECL that contains unexpanded parameter
5934 packs. We have already complained about this in the
5935 check_for_bare_parameter_packs call, so just replace
5936 these types with ERROR_MARK_NODE. */
5939 }
5943 }
5945 /* Check for bare parameter packs in the return type and the
5946 exception specifiers. */
5948 /* Errors were already issued, set return type to int
5949 as the frontend doesn't expect error_mark_node as
5950 the return type. */
5954 }
5955 else
5956 {
5960 {
5963 }
5968 }
5977 {
5978 /* Does not get a template head. */
5981 }
5988 {
5993 /* If DECL is a TYPE_DECL for a class-template, then there won't
5994 be DECL_LANG_SPECIFIC. The information equivalent to
5995 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5999 {
6000 /* Since a template declaration already existed for this
6001 class-type, we must be redeclaring it here. Make sure
6002 that the redeclaration is valid. */
6004 current_template_parms,
6006 /* We don't need to create a new TEMPLATE_DECL; just use the
6007 one we already had. */
6009 }
6010 else
6011 {
6013 member_template_p);
6018 {
6019 /* A specialization of a member template of a template
6020 class. */
6024 }
6025 }
6026 }
6027 else
6028 {
6034 {
6037 }
6045 {
6046 /* The declaration is a specialization of a member
6047 template, declared outside the class. Therefore, the
6048 innermost template arguments will be NULL, so we
6049 replace them with the arguments determined by the
6050 earlier call to check_explicit_specialization. */
6053 tree new_tmpl
6055 member_template_p);
6063 args,
6066 }
6068 /* Make sure the template headers we got make sense. */
6073 {
6078 }
6079 else
6081 {
6086 {
6090 else
6094 /* Avoid crash in import_export_decl. */
6097 }
6102 /* Can happen in erroneous input. */
6104 else
6106 }
6108 /* Check that the parms are used in the appropriate qualifying scopes
6109 in the declarator. */
6113 {
6119 /* Avoid crash in import_export_decl. */
6122 }
6123 }
6128 {
6129 /* Push template declarations for global functions and types.
6130 Note that we do not try to push a global template friend
6131 declared in a template class; such a thing may well depend on
6132 the template parameters of the class and we'll push it when
6133 instantiating the befriending class. */
6136 {
6141 /* pushdecl may have found an existing template. */
6143 {
6146 }
6147 }
6149 {
6150 /* Record this decl as belonging to the current class. It's
6151 not chained onto anything else. */
6155 }
6156 }
6158 /* The type may have been completed, or (erroneously) changed. */
6162 {
6164 {
6169 /* Give template template parms a DECL_CONTEXT of the template
6170 for which they are a parameter. */
6173 {
6177 }
6181 {
6184 {
6185 /* ??? Why don't we do this here for all templates? */
6188 }
6191 }
6192 }
6194 /* The DECL_TI_ARGS of DECL contains full set of arguments
6195 referring wback to its most general template. If TMPL is a
6196 specialization, ARGS may only have the innermost set of
6197 arguments. Add the missing argument levels if necessary. */
6205 else
6206 {
6209 }
6210 }
6213 && !is_friend
6216 /* Set DECL_COMDAT on template instantiations; if we force
6217 them to be emitted by explicit instantiation,
6218 mark_needed will tell cgraph to do the right thing. */
6224 }
6226 /* FN is an inheriting constructor that inherits from the constructor
6227 template INHERITED; turn FN into a constructor template with a matching
6228 template header. */
6230 tree
6232 {
6233 tree inner_parms
6236 tree parms
6245 }
6247 /* Called when a class template TYPE is redeclared with the indicated
6248 template PARMS, e.g.:
6250 template <class T> struct S;
6251 template <class T> struct S {}; */
6253 bool
6255 {
6256 tree tmpl;
6257 tree tmpl_parms;
6261 {
6264 }
6268 /* The type is nested in some template class. Nothing to worry
6269 about here; there are no new template parameters for the nested
6270 type. */
6274 {
6276 tmpl);
6278 }
6284 {
6294 }
6297 {
6298 tree tmpl_parm;
6299 tree parm;
6311 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
6312 TEMPLATE_DECL. */
6322 {
6323 auto_diagnostic_group d;
6327 }
6329 /* The parameters can be declared to introduce different
6330 constraints. */
6334 {
6335 auto_diagnostic_group d;
6341 }
6343 /* Give each template template parm in this redeclaration a
6344 DECL_CONTEXT of the template for which they are a parameter. */
6346 {
6349 }
6350 }
6359 /* Two classes with different constraints declare different entities. */
6361 {
6362 auto_diagnostic_group d;
6368 }
6371 }
6373 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
6374 to be used when the caller has already checked
6375 !instantiation_dependent_uneval_expression_p (expr)
6376 and cleared processing_template_decl. */
6378 tree
6380 {
6383 complain,
6387 }
6389 /* Instantiate the non-dependent expression EXPR. */
6391 tree
6393 {
6398 {
6399 /* The caller should have checked this already. */
6401 processing_template_decl_sentinel s;
6403 }
6405 }
6407 tree
6409 {
6411 }
6413 /* Like instantiate_non_dependent_expr, but return NULL_TREE if the
6414 expression is dependent or non-constant. */
6416 tree
6418 {
6422 {
6425 else
6426 {
6427 processing_template_decl_sentinel s;
6429 }
6430 }
6432 }
6434 /* True iff T is a specialization of a variable template. */
6436 bool
6438 {
6443 }
6445 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
6446 template declaration, or a TYPE_DECL for an alias declaration. */
6448 bool
6450 {
6458 }
6460 /* If T is a specialization of an alias template, return it; otherwise return
6461 NULL_TREE. If TRANSPARENT_TYPEDEFS is true, look through other aliases. */
6463 tree
6466 {
6470 /* It's an alias template specialization if it's an alias and its
6471 TYPE_NAME is a specialization of a primary template. */
6473 {
6480 transparent_typedefs);
6481 }
6484 }
6486 /* Data structure for complex_alias_template_*. */
6488 struct uses_all_template_parms_data
6489 {
6492 };
6494 /* walk_tree callback for complex_alias_template_p. */
6496 static tree
6498 {
6503 {
6508 {
6512 }
6515 }
6520 /* An alias template with a pack expansion that expands a pack from the
6521 enclosing class needs to be considered complex, to avoid confusion with
6522 the same pack being used as an argument to the alias's own template
6523 parameter (91966). */
6526 {
6535 /* Consider the expanded packs to be used outside the expansion... */
6537 }
6539 /* ...but don't walk into the pattern. Consider PR104008:
6541 template <typename T, typename... Ts>
6542 using IsOneOf = disjunction<is_same<T, Ts>...>;
6544 where IsOneOf seemingly uses all of its template parameters in its
6545 expansion (and does not expand a pack from the enclosing class), so the
6546 alias was not marked as complex. However, if it is used like
6547 "IsOneOf<T>", the empty pack for Ts means that T no longer appears in the
6548 expansion. So only Ts is considered used by the pack expansion. */
6552 }
6554 /* An alias template is complex from a SFINAE perspective if a template-id
6555 using that alias can be ill-formed when the expansion is not, as with
6556 the void_t template.
6558 Returns 1 if always complex, 0 if not complex, -1 if complex iff any of the
6559 template arguments are empty packs. */
6561 static bool
6563 {
6564 /* A renaming alias isn't complex. */
6568 /* Any other constrained alias is complex. */
6587 }
6589 /* If T is a specialization of a complex alias template with dependent
6590 template-arguments, return it; otherwise return NULL_TREE. If T is a
6591 typedef to such a specialization, return the specialization. */
6593 tree
6595 {
6606 && (any_dependent_template_arguments_p
6611 {
6614 }
6617 }
6619 /* Return the number of innermost template parameters in TMPL. */
6621 static int
6623 {
6626 }
6628 /* Return either TMPL or another template that it is equivalent to under DR
6629 1286: An alias that just changes the name of a template is equivalent to
6630 the other template. */
6632 static tree
6634 {
6637 {
6638 /* Determine if the alias is equivalent to an underlying template. */
6640 /* The underlying type may have been ill-formed. Don't proceed. */
6653 /* Does the alias add cv-quals? */
6661 /* Are any default template arguments equivalent? */
6666 {
6671 }
6673 /* If TMPL adds or changes any constraints, it isn't equivalent. I think
6674 it's appropriate to treat a less-constrained alias as equivalent. */
6678 /* Alias is equivalent. Strip it and repeat. */
6680 }
6681 top_break:;
6684 }
6686 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6687 must be a reference-to-function or a pointer-to-function type, as specified
6688 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6689 and check that the resulting function has external linkage. */
6691 static tree
6693 tsubst_flags_t complain)
6694 {
6697 linkage_kind linkage;
6715 /* [temp.arg.nontype]/1
6717 A template-argument for a non-type, non-template template-parameter
6718 shall be one of:
6719 [...]
6720 -- the address of an object or function with external [C++11: or
6721 internal] linkage. */
6725 {
6727 {
6734 else
6737 }
6739 }
6743 {
6745 {
6751 else
6755 }
6757 }
6759 accept:
6761 {
6764 else
6766 }
6771 }
6773 /* Subroutine of convert_nontype_argument.
6774 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6775 Emit an error otherwise. */
6777 static bool
6779 tsubst_flags_t complain)
6780 {
6796 {
6802 else
6804 }
6806 }
6808 /* Returns TRUE iff the address of OP is value-dependent.
6810 14.6.2.4 [temp.dep.temp]:
6811 A non-integral non-type template-argument is dependent if its type is
6812 dependent or it has either of the following forms
6813 qualified-id
6814 & qualified-id
6815 and contains a nested-name-specifier which specifies a class-name that
6816 names a dependent type.
6818 We generalize this to just say that the address of a member of a
6819 dependent class is value-dependent; the above doesn't cover the
6820 address of a static data member named with an unqualified-id. */
6822 static bool
6824 {
6827 /* We could use get_inner_reference here, but there's no need;
6828 this is only relevant for template non-type arguments, which
6829 can only be expressed as &id-expression. */
6831 {
6842 }
6845 }
6847 /* The next set of functions are used for providing helpful explanatory
6848 diagnostics for failed overload resolution. Their messages should be
6849 indented by two spaces for consistency with the messages in
6850 call.cc */
6852 static int
6854 {
6856 }
6858 /* Other failure functions should call this one, to provide a single function
6859 for setting a breakpoint on. */
6861 static int
6863 {
6865 }
6867 static int
6869 {
6874 }
6876 static int
6878 {
6884 }
6886 static int
6888 {
6892 }
6894 static int
6896 {
6899 " template parameter %qD is not a parameter pack, but "
6903 }
6905 static int
6907 {
6910 " template argument %qE does not match "
6914 }
6916 static int
6918 {
6922 }
6924 static int
6926 {
6932 }
6934 static int
6936 {
6938 {
6943 else
6945 " deduced conflicting values for non-type parameter "
6947 }
6949 }
6951 static int
6953 {
6956 " variable-sized array type %qT is not "
6958 arg);
6960 }
6962 static int
6964 {
6968 arg);
6970 }
6972 static int
6974 {
6976 {
6982 else
6987 }
6989 }
6991 static int
6993 {
6995 }
6997 static int
7000 {
7002 }
7004 static int
7007 {
7013 }
7015 static int
7018 {
7021 {
7029 }
7031 }
7033 static int
7035 {
7038 " template parameters of a template template argument are "
7041 }
7043 static int
7045 {
7051 }
7053 static int
7055 {
7060 }
7062 /* True if T is a C++20 template parameter object to store the argument for a
7063 template parameter of class type. */
7065 bool
7067 {
7070 }
7072 /* Subroutine of convert_nontype_argument, to check whether EXPR, as an
7073 argument for TYPE, points to an unsuitable object.
7075 Also adjust the type of the index in C++20 array subobject references. */
7077 static bool
7079 {
7081 {
7082 CASE_CONVERT:
7084 complain);
7088 complain);
7091 {
7095 }
7099 {
7105 {
7109 /* Canonicalize array offsets to ptrdiff_t; how they were
7110 written doesn't matter for subobject identity. */
7113 }
7116 {
7119 "%qE is not a valid template argument of type %qT "
7122 }
7124 {
7127 "%qE is not a valid template argument of type %qT "
7131 }
7134 {
7137 "%qE is not a valid template argument of type %qT "
7140 }
7141 /* C++17: For a non-type template-parameter of reference or pointer
7142 type, the value of the constant expression shall not refer to (or
7143 for a pointer type, shall not be the address of):
7144 * a subobject (4.5),
7145 * a temporary object (15.2),
7146 * a string literal (5.13.5),
7147 * the result of a typeid expression (8.2.8), or
7148 * a predefined __func__ variable (11.4.1). */
7150 {
7153 decl);
7155 }
7157 && !(same_type_ignoring_top_level_qualifiers_p
7160 {
7165 }
7167 {
7171 decl);
7173 }
7174 }
7182 else
7183 {
7185 {
7188 "because %qD is a variable, not the address of "
7191 }
7192 else
7193 {
7199 }
7200 }
7201 }
7204 }
7206 /* The template arguments corresponding to template parameter objects of types
7207 that contain pointers to members. */
7211 /* Return a VAR_DECL for the C++20 template parameter object corresponding to
7212 template argument EXPR. */
7214 static tree
7216 {
7221 {
7226 }
7230 /* This is no longer a compound literal. */
7249 {
7250 /* If EXPR contains any PTRMEM_CST, they will get clobbered by
7251 lower_var_init before we're done mangling. So store the original
7252 value elsewhere. */
7255 }
7260 }
7262 /* Return the actual template argument corresponding to template parameter
7263 object VAR. */
7265 tree
7267 {
7271 }
7273 /* Attempt to convert the non-type template parameter EXPR to the
7274 indicated TYPE. If the conversion is successful, return the
7275 converted value. If the conversion is unsuccessful, return
7276 NULL_TREE if we issued an error message, or error_mark_node if we
7277 did not. We issue error messages for out-and-out bad template
7278 parameters, but not simply because the conversion failed, since we
7279 might be just trying to do argument deduction. Both TYPE and EXPR
7280 must be non-dependent.
7282 The conversion follows the special rules described in
7283 [temp.arg.nontype], and it is much more strict than an implicit
7284 conversion.
7286 This function is called twice for each template argument (see
7287 lookup_template_class for a more accurate description of this
7288 problem). This means that we need to handle expressions which
7289 are not valid in a C++ source, but can be created from the
7290 first call (for instance, casts to perform conversions). These
7291 hacks can go away after we fix the double coercion problem. */
7293 static tree
7295 {
7296 tree expr_type;
7299 /* Detect immediately string literals as invalid non-type argument.
7300 This special-case is not needed for correctness (we would easily
7301 catch this later), but only to provide better diagnostic for this
7302 common user mistake. As suggested by DR 100, we do not mention
7303 linkage issues in the diagnostic as this is not the point. */
7305 {
7311 }
7313 /* Add the ADDR_EXPR now for the benefit of
7314 value_dependent_expression_p. */
7317 {
7321 }
7323 /* If we are in a template, EXPR may be non-dependent, but still
7324 have a syntactic, rather than semantic, form. For example, EXPR
7325 might be a SCOPE_REF, rather than the VAR_DECL to which the
7326 SCOPE_REF refers. Preserving the qualifying scope is necessary
7327 so that access checking can be performed when the template is
7328 instantiated -- but here we need the resolved form so that we can
7329 convert the argument. */
7341 /* If the argument is non-dependent, perform any conversions in
7342 non-dependent context as well. */
7350 else
7353 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
7354 to a non-type argument of "nullptr". */
7358 /* In C++11, integral or enumeration non-type template arguments can be
7359 arbitrary constant expressions. Pointer and pointer to
7360 member arguments can be general constant expressions that evaluate
7361 to a null value, but otherwise still need to be of a specific form. */
7363 {
7365 /* A PTRMEM_CST is already constant, and a valid template
7366 argument for a parameter of pointer to member type, we just want
7367 to leave it in that form rather than lower it to a
7371 {
7372 /* C++17: A template-argument for a non-type template-parameter shall
7373 be a converted constant expression (8.20) of the type of the
7374 template-parameter. */
7377 /* Make sure we return NULL_TREE only if we have really issued
7378 an error, as described above. */
7381 {
7384 }
7388 /* EXPR may have become value-dependent. */
7390 }
7392 {
7398 }
7399 }
7403 else
7406 /* HACK: Due to double coercion, we can get a
7407 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
7408 which is the tree that we built on the first call (see
7409 below when coercing to reference to object or to reference to
7410 function). We just strip everything and get to the arg.
7411 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
7412 for examples. */
7414 {
7415 /* Check this before we strip *& to avoid redundancy. */
7424 {
7425 /* ??? Maybe we could use convert_from_reference here, but we
7426 would need to relax its constraints because the NOP_EXPR
7427 could actually change the type to something more cv-qualified,
7428 and this is not folded by convert_from_reference. */
7433 && (same_type_ignoring_top_level_qualifiers_p
7436 {
7439 }
7440 }
7441 }
7443 /* [temp.arg.nontype]/5, bullet 1
7445 For a non-type template-parameter of integral or enumeration type,
7446 integral promotions (_conv.prom_) and integral conversions
7447 (_conv.integral_) are applied. */
7450 {
7452 {
7457 }
7462 /* Notice that there are constant expressions like '4 % 0' which
7463 do not fold into integer constants. */
7465 {
7467 {
7471 else
7477 /* else cxx_constant_value complained but gave us
7478 a real constant, so go ahead. */
7480 {
7481 /* Some assemble time constant expressions like
7482 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
7483 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
7484 as we can emit them into .rodata initializers of
7485 variables, yet they can't fold into an INTEGER_CST at
7486 compile time. Refuse them here. */
7491 }
7492 }
7493 else
7495 }
7497 /* Avoid typedef problems. */
7500 }
7501 /* [temp.arg.nontype]/5, bullet 2
7503 For a non-type template-parameter of type pointer to object,
7504 qualification conversions (_conv.qual_) and the array-to-pointer
7505 conversion (_conv.array_) are applied. */
7507 {
7510 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
7511 decay_conversion or an explicit cast. If it's a problematic cast,
7512 we'll complain about it below. */
7514 {
7519 {
7522 }
7523 }
7525 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
7527 A template-argument for a non-type, non-template template-parameter
7528 shall be one of: [...]
7530 -- the name of a non-type template-parameter;
7531 -- the address of an object or function with external linkage, [...]
7532 expressed as "& id-expression" where the & is optional if the name
7533 refers to a function or array, or if the corresponding
7534 template-parameter is a reference.
7536 Here, we do not care about functions, as they are invalid anyway
7537 for a parameter of type pointer-to-object. */
7540 /* Non-type template parameters are OK. */
7541 ;
7546 /* Other values, like integer constants, might be valid
7547 non-type arguments of some other type. */
7557 }
7558 /* [temp.arg.nontype]/5, bullet 3
7560 For a non-type template-parameter of type reference to object, no
7561 conversions apply. The type referred to by the reference may be more
7562 cv-qualified than the (otherwise identical) type of the
7563 template-argument. The template-parameter is bound directly to the
7564 template-argument, which must be an lvalue. */
7566 {
7568 expr_type))
7572 {
7577 }
7580 {
7585 }
7587 /* [temp.arg.nontype]/1
7589 A template-argument for a non-type, non-template template-parameter
7590 shall be one of: [...]
7592 -- the address of an object or function with external linkage. */
7595 {
7598 {
7601 "because a reference variable does not have a constant "
7604 }
7605 }
7608 /* OK, dependent reference. We don't want to ask whether a DECL is
7610 else
7611 {
7616 }
7620 }
7621 /* [temp.arg.nontype]/5, bullet 4
7623 For a non-type template-parameter of type pointer to function, only
7624 the function-to-pointer conversion (_conv.func_) is applied. If the
7625 template-argument represents a set of overloaded functions (or a
7626 pointer to such), the matching function is selected from the set
7627 (_over.over_). */
7629 {
7630 /* If the argument is a template-id, we might not have enough
7631 context information to decay the pointer. */
7633 {
7637 }
7640 /* Null pointer values are OK in C++11. */
7646 }
7647 /* [temp.arg.nontype]/5, bullet 5
7649 For a non-type template-parameter of type reference to function, no
7650 conversions apply. If the template-argument represents a set of
7651 overloaded functions, the matching function is selected from the set
7652 (_over.over_). */
7654 {
7656 {
7658 {
7663 }
7665 }
7670 }
7671 /* [temp.arg.nontype]/5, bullet 6
7673 For a non-type template-parameter of type pointer to member function,
7674 no conversions apply. If the template-argument represents a set of
7675 overloaded member functions, the matching member function is selected
7676 from the set (_over.over_). */
7678 {
7683 /* [temp.arg.nontype] bullet 1 says the pointer to member
7684 expression must be a pointer-to-member constant. */
7689 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
7690 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
7693 }
7694 /* [temp.arg.nontype]/5, bullet 7
7696 For a non-type template-parameter of type pointer to data member,
7697 qualification conversions (_conv.qual_) are applied. */
7699 {
7700 /* [temp.arg.nontype] bullet 1 says the pointer to member
7701 expression must be a pointer-to-member constant. */
7709 }
7711 {
7713 {
7718 }
7720 }
7722 {
7723 /* Replace the argument with a reference to the corresponding template
7724 parameter object. */
7729 }
7730 /* A template non-type parameter must be one of the above. */
7731 else
7734 /* Sanity check: did we actually convert the argument to the
7735 right type? */
7739 }
7741 /* Subroutine of coerce_template_template_parms, which returns 1 if
7742 PARM_PARM and ARG_PARM match using the rule for the template
7743 parameters of template template parameters. Both PARM and ARG are
7744 template parameters; the rest of the arguments are the same as for
7745 coerce_template_template_parms.
7746 */
7747 static int
7749 tree arg,
7750 tsubst_flags_t complain,
7751 tree in_decl,
7752 tree outer_args)
7753 {
7762 {
7764 /* We encounter instantiations of templates like
7765 template <template <template <class> class> class TT>
7766 class C; */
7767 {
7774 }
7775 /* Fall through. */
7780 /* Argument is a parameter pack but parameter is not. */
7785 /* The tsubst call is used to handle cases such as
7787 template <int> class C {};
7788 template <class T, template <T> class TT> class D {};
7789 D<int, C> d;
7791 i.e. the parameter list of TT depends on earlier parameters. */
7793 {
7798 }
7802 /* Argument is a parameter pack but parameter is not. */
7809 }
7812 }
7814 /* Coerce template argument list ARGLIST for use with template
7815 template-parameter TEMPL. */
7817 static tree
7819 tsubst_flags_t complain)
7820 {
7821 /* Consider an example where a template template parameter declared as
7823 template <class T, class U = std::allocator<T> > class TT
7825 The template parameter level of T and U are one level larger than
7826 of TT. To proper process the default argument of U, say when an
7827 instantiation `TT<int>' is seen, we need to build the full
7828 arguments containing {int} as the innermost level. Outer levels,
7829 available when not appearing as default template argument, can be
7830 obtained from the arguments of the enclosing template.
7832 Suppose that TT is later substituted with std::vector. The above
7833 instantiation is `TT<int, std::allocator<T> >' with TT at
7834 level 1, and T at level 2, while the template arguments at level 1
7835 becomes {std::vector} and the inner level 2 is {int}. */
7841 {
7842 /* This is an argument of the current template, so we haven't set
7843 DECL_CONTEXT yet. */
7844 tree relevant_template_parms;
7846 /* Parameter levels that are greater than the level of the given
7847 template template parm are irrelevant. */
7854 }
7861 complain,
7864 }
7866 /* A cache of template template parameters with match-all default
7867 arguments. */
7870 /* T is a bound template template-parameter. Copy its arguments into default
7871 arguments of the template template-parameter's template parameters. */
7873 static tree
7875 {
7898 {
7901 {
7904 }
7905 }
7909 }
7911 /* ARG is a bound potential template template-argument, and PARGS is a list
7912 of arguments for the corresponding template template-parameter. Adjust
7913 PARGS as appropriate for application to ARG's template, and if ARG is a
7914 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7915 arguments to the template template parameter. */
7917 static tree
7919 {
7923 {
7924 /* When comparing two template template-parameters in partial ordering,
7925 rewrite the one currently being used as an argument to have default
7926 arguments for all parameters. */
7932 }
7933 else
7934 {
7935 tree aparms
7940 }
7943 }
7945 /* Subroutine of unify for the case when PARM is a
7946 BOUND_TEMPLATE_TEMPLATE_PARM. */
7948 static int
7951 {
7955 /* The template template parm might be variadic and the argument
7956 not, so flatten both argument lists. */
7961 {
7962 /* In keeping with P0522R0, adjust P's template arguments
7963 to apply to A's template; then flatten it again. */
7971 /* If the P0522 adjustment eliminated a pack expansion, deduce
7972 empty packs. */
7978 }
7979 else
7980 {
7981 /* Deduce arguments T, i from TT<T> or TT<i>.
7982 We check each element of PARMVEC and ARGVEC individually
7983 rather than the whole TREE_VEC since they can have
7984 different number of elements, which is allowed under N2555. */
7988 /* Check if the parameters end in a pack, making them
7989 variadic. */
7996 /* If the template argument list of P contains a pack
7997 expansion that is not the last template argument, the
7998 entire template argument list is a non-deduced
7999 context. */
8017 DEDUCE_EXACT,
8020 }
8023 }
8025 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
8026 template template parameters. Both PARM_PARMS and ARG_PARMS are
8027 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
8028 or PARM_DECL.
8030 Consider the example:
8031 template <class T> class A;
8032 template<template <class U> class TT> class B;
8034 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
8035 the parameters to A, and OUTER_ARGS contains A. */
8037 static int
8039 tree arg_parms_full,
8040 tsubst_flags_t complain,
8041 tree in_decl,
8042 tree outer_args)
8043 {
8058 {
8059 /* P0522R0: A template template-parameter P is at least as specialized as
8060 a template template-argument A if, given the following rewrite to two
8061 function templates, the function template corresponding to P is at
8062 least as specialized as the function template corresponding to A
8063 according to the partial ordering rules for function templates
8064 ([temp.func.order]). Given an invented class template X with the
8065 template parameter list of A (including default arguments):
8067 * Each of the two function templates has the same template parameters,
8068 respectively, as P or A.
8070 * Each function template has a single function parameter whose type is
8071 a specialization of X with template arguments corresponding to the
8072 template parameters from the respective function template where, for
8073 each template parameter PP in the template parameter list of the
8074 function template, a corresponding template argument AA is formed. If
8075 PP declares a parameter pack, then AA is the pack expansion
8076 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
8078 If the rewrite produces an invalid type, then P is not at least as
8079 specialized as A. */
8081 /* So coerce P's args to apply to A's parms, and then deduce between A's
8082 args and the converted args. If that succeeds, A is at least as
8083 specialized as P, so they match.*/
8089 /* PARM, and thus the context in which we are passing ARG to it, may be
8090 at a deeper level than ARG; when trying to coerce to ARG_PARMS, we
8091 want to provide the right number of levels, so we reduce the number of
8092 levels in OUTER_ARGS before prepending them. This is most important
8093 when ARG is a namespace-scope template, as in alias-decl-ttp2.C.
8095 ARG might also be deeper than PARM (ttp23). In that case, we include
8096 all of OUTER_ARGS. The missing levels seem potentially problematic,
8097 but I can't come up with a testcase that breaks. */
8099 {
8104 }
8109 {
8115 }
8116 }
8118 /* Determine whether we have a parameter pack at the end of the
8119 template template parameter's template parameter list. */
8121 {
8128 {
8142 }
8143 }
8149 /* Check all of the template parameters except the parameter pack at
8150 the end (if any). */
8152 {
8161 outer_args))
8164 }
8167 {
8168 /* Check each of the template parameters in the template
8169 argument against the template parameter pack at the end of
8170 the template template parameter. */
8177 {
8184 outer_args))
8186 }
8187 }
8190 }
8192 /* Verifies that the deduced template arguments (in TARGS) for the
8193 template template parameters (in TPARMS) represent valid bindings,
8194 by comparing the template parameter list of each template argument
8195 to the template parameter list of its corresponding template
8196 template parameter, in accordance with DR150. This
8197 routine can only be called after all template arguments have been
8198 deduced. It will return TRUE if all of the template template
8199 parameter bindings are okay, FALSE otherwise. */
8200 bool
8202 {
8206 /* We're dealing with template parms in this process. */
8212 {
8217 {
8222 {
8223 /* Look inside the argument pack. */
8226 }
8229 {
8233 /* Extract the next argument from the argument
8234 pack. */
8238 /* Look at the pattern of the pack expansion. */
8241 /* Extract the template parameters from the template
8242 argument. */
8248 /* Verify that we can coerce the template template
8249 parameters from the template argument to the template
8250 parameter. This requires an exact match. */
8252 && !coerce_template_template_parms
8254 targ_parms,
8255 tf_none,
8256 tparm,
8257 targs))
8258 {
8261 }
8262 }
8263 }
8264 }
8266 out:
8270 }
8272 /* Since type attributes aren't mangled, we need to strip them from
8273 template type arguments. */
8275 tree
8277 {
8287 }
8289 /* And from inside dependent non-type arguments like sizeof(Type). */
8291 static tree
8293 {
8303 }
8305 /* A template declaration can be substituted for a constrained
8306 template template parameter only when the argument is no more
8307 constrained than the parameter. */
8309 static bool
8311 {
8314 /* For now, allow constrained template template arguments
8315 and unconstrained template template parameters. */
8319 /* If the template parameter is constrained, we need to rewrite its
8320 constraints in terms of the ARG's template parameters. This ensures
8321 that all of the template parameter types will have the same depth.
8323 Note that this is only valid when coerce_template_template_parm is
8324 true for the innermost template parameters of PARM and ARG. In other
8325 words, because coercion is successful, this conversion will be valid. */
8328 {
8337 }
8340 }
8342 // Convert a placeholder argument into a binding to the original
8343 // parameter. The original parameter is saved as the TREE_TYPE of
8344 // ARG.
8347 {
8350 }
8352 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
8353 because one of them is dependent. But we need to represent the
8354 conversion for the benefit of cp_tree_equal. */
8356 static tree
8358 {
8359 /* Auto parms get no conversion. */
8362 /* We don't need or want to add this conversion now if we're going to use the
8363 argument for deduction. */
8375 }
8377 /* Convert the indicated template ARG as necessary to match the
8378 indicated template PARM. Returns the converted ARG, or
8379 error_mark_node if the conversion was unsuccessful. Error and
8380 warning messages are issued under control of COMPLAIN. This
8381 conversion is for the Ith parameter in the parameter list. ARGS is
8382 the full set of template arguments deduced so far. */
8384 static tree
8386 tree arg,
8387 tree args,
8388 tsubst_flags_t complain,
8390 tree in_decl)
8391 {
8392 tree orig_arg;
8393 tree val;
8399 /* Trivially convert placeholders. */
8408 {
8409 /* The template argument was the name of some
8410 member function. That's usually
8411 invalid, but static members are OK. In any
8412 case, grab the underlying fields/functions
8413 and issue an error later if required. */
8415 }
8423 /* When determining whether an argument pack expansion is a template,
8424 look at the pattern. */
8428 /* Deal with an injected-class-name used as a template template arg. */
8430 {
8433 {
8443 }
8444 }
8446 is_tmpl_type =
8462 {
8464 {
8468 }
8471 "to refer to a type member of a template parameter, "
8476 typename_type,
8477 complain);
8480 }
8482 {
8484 {
8486 {
8491 {
8492 /* The template argument is a type, but we're expecting
8493 an expression. */
8498 /* [temp.arg]/2: "In a template-argument, an ambiguity
8499 between a type-id and an expression is resolved to a
8500 type-id, regardless of the form of the corresponding
8501 template-parameter." So give the user a clue. */
8504 "for non-type template parameter is treated as "
8506 }
8510 else
8513 }
8514 }
8516 }
8518 {
8520 {
8527 else
8530 }
8532 }
8535 /* We already did the appropriate conversion when packing args. */
8538 {
8540 {
8542 /* The number of argument required is not known yet.
8543 Just accept it for now. */
8545 else
8546 {
8548 tree argparm;
8550 /* Strip alias templates that are equivalent to another
8551 template. */
8557 args))
8558 {
8561 /* TEMPLATE_TEMPLATE_PARM node is preferred over
8562 TEMPLATE_DECL. */
8564 {
8569 }
8570 }
8571 else
8572 {
8574 {
8581 }
8584 }
8586 // Check that the constraints are compatible before allowing the
8587 // substitution.
8590 {
8592 {
8598 }
8600 }
8601 }
8602 }
8603 else
8605 /* We only form one instance of each template specialization.
8606 Therefore, if we use a non-canonical variant (i.e., a
8607 typedef), any future messages referring to the type will use
8608 the typedef, which is confusing if those future uses do not
8609 themselves also use the typedef. */
8612 }
8613 else
8614 {
8619 /* We don't have enough levels of args to do any substitution. This
8622 {
8624 LOOKUP_IMPLICIT);
8627 }
8628 else
8631 /* Perform array-to-pointer and function-to-pointer conversion
8632 as per [temp.param]/10. */
8638 /* Drop top-level cv-qualifiers on the substituted/deduced type of
8639 this non-type template parameter, as per [temp.param]/6. */
8647 /* We used to call digest_init here. However, digest_init
8648 will report errors, which we don't want when complain
8649 is zero. More importantly, digest_init will try too
8650 hard to convert things: for example, `0' should not be
8651 converted to pointer type at this point according to
8652 the standard. Accepting this is not merely an
8653 extension, since deciding whether or not these
8654 conversions can occur is part of determining which
8655 function template to call, or whether a given explicit
8656 argument specification is valid. */
8658 else
8659 {
8662 }
8673 {
8674 /* Reject template arguments that are references to built-in
8675 functions with no library fallbacks. */
8684 }
8687 {
8688 /* Strip typedefs from the SCOPE_REF. */
8691 complain);
8694 }
8695 }
8698 }
8700 /* Coerces the remaining template arguments in INNER_ARGS (from
8701 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
8702 Returns the coerced argument pack. PARM_IDX is the position of this
8703 parameter in the template parameter list. ARGS is the original
8704 template argument list. */
8705 static tree
8708 tree args,
8709 tree inner_args,
8711 tree new_args,
8713 tree in_decl,
8714 tsubst_flags_t complain)
8715 {
8718 tree packed_args;
8719 tree argument_pack;
8726 {
8727 /* When the template parameter is a non-type template parameter pack
8728 or template template parameter pack whose type or template
8729 parameters use parameter packs, we know exactly how many arguments
8730 we are looking for. Build a vector of the instantiated decls for
8731 these template parameters in PACKED_PARMS. */
8732 /* We can't use make_pack_expansion here because it would interpret a
8733 _DECL as a use rather than a declaration. */
8747 /* If we're doing a partial instantiation of a member template,
8748 verify that all of the types used for the non-type
8749 template parameter pack are, in fact, valid for non-type
8750 template parameters. */
8753 {
8756 {
8761 }
8762 /* We don't know how many args we have yet, just
8763 use the unconverted ones for now. */
8765 }
8768 }
8769 /* Check if we have a placeholder pack, which indicates we're
8770 in the context of a introduction list. In that case we want
8771 to match this pack to the single placeholder. */
8775 {
8778 }
8779 else
8782 /* Convert the remaining arguments, which will be a part of the
8783 parameter pack "parm". */
8786 {
8792 {
8793 /* Once we've packed as many args as we have types, stop. */
8797 /* We don't know how many args we have yet, just
8798 use the unconverted ones for now. */
8800 else
8802 }
8805 {
8808 }
8809 else
8812 in_decl);
8816 }
8820 {
8825 }
8830 else
8831 {
8834 }
8841 }
8843 /* Returns the number of pack expansions in the template argument vector
8844 ARGS. */
8846 static int
8848 {
8853 {
8857 }
8859 }
8861 /* Convert all template arguments to their appropriate types, and
8862 return a vector containing the innermost resulting template
8863 arguments. If any error occurs, return error_mark_node. Error and
8864 warning messages are issued under control of COMPLAIN.
8866 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8867 for arguments not specified in ARGS. Otherwise, if
8868 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
8869 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
8870 USE_DEFAULT_ARGS is false, then all arguments must be specified in
8871 ARGS. */
8873 static tree
8875 tree args,
8876 tree in_decl,
8877 tsubst_flags_t complain,
8880 {
8882 tree orig_inner_args;
8883 tree inner_args;
8884 tree new_args;
8885 tree new_inner_args;
8887 /* When used as a boolean value, indicates whether this is a
8888 variadic template parameter list. Since it's an int, we can also
8889 subtract it from nparms to get the number of non-variadic
8890 parameters. */
8895 /* Adjustment to nparms for fixed parameter packs. */
8900 /* Likewise for parameters with default arguments. */
8908 /* Determine if there are any parameter packs or default arguments. */
8910 {
8918 }
8921 /* If there are no parameters that follow a parameter pack, we need to
8922 expand any argument packs so that we can deduce a parameter pack from
8923 some non-packed args followed by an argument pack, as in variadic85.C.
8924 If there are such parameters, we need to leave argument packs intact
8925 so the arguments are assigned properly. This can happen when dealing
8926 with a nested class inside a partial specialization of a class
8927 template, as in variadic92.C, or when deducing a template parameter pack
8928 from a sub-declarator, as in variadic114.C. */
8932 /* Count any pack expansion args. */
8938 && require_all_args
8939 && !variadic_args_p
8940 && (!use_default_args
8943 {
8944 bad_nargs:
8946 {
8948 {
8952 }
8953 else
8960 }
8963 }
8964 /* We can't pass a pack expansion to a non-pack parameter of an alias
8965 template (DR 1430). */
8969 && variadic_args_p
8971 {
8973 {
8975 {
8981 {
8984 "pack expansion argument for non-pack parameter "
8986 else
8988 "pack expansion argument for non-pack parameter "
8992 }
8993 }
8995 found:;
8996 }
8998 }
9000 /* We need to evaluate the template arguments, even though this
9001 template-id may be nested within a "sizeof". */
9002 cp_evaluated ev;
9008 {
9009 tree arg;
9010 tree parm;
9012 /* Get the Ith template parameter. */
9016 {
9019 }
9021 /* Calculate the next argument. */
9024 else
9030 {
9031 /* Some arguments will be placed in the
9032 template parameter pack PARM. */
9039 {
9040 /* We don't know how many args we have yet, just use the
9041 unconverted (and still packed) ones for now. */
9045 }
9049 /* Store this argument. */
9051 {
9052 lost++;
9053 /* We are done with all of the arguments. */
9056 }
9057 else
9058 {
9062 {
9065 }
9066 }
9069 }
9071 {
9073 {
9074 /* "If every valid specialization of a variadic template
9075 requires an empty template parameter pack, the template is
9076 ill-formed, no diagnostic required." So check that the
9077 pattern works with this parameter. */
9082 in_decl);
9084 {
9089 }
9091 /* Recover from missing typename. */
9095 /* We don't know how many args we have yet, just
9096 use the unconverted ones for now. */
9100 }
9101 }
9103 {
9104 /* There must be a default arg in this case. */
9107 /* The position of the first default template argument,
9108 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
9109 Record that. */
9113 }
9114 else
9118 {
9121 }
9123 {
9124 /* This can occur if there was an error in the template
9125 parameter list itself (which we would already have
9126 reported) that we are trying to recover from, e.g., a class
9127 template with a parameter list such as
9128 template<typename..., typename> (cpp0x/variadic150.C). */
9131 /* This can also happen with a fixed parameter pack (71834). */
9134 }
9135 else
9141 lost++;
9144 }
9147 {
9148 /* If we had fixed parameter packs, we didn't know how many arguments we
9149 actually needed earlier; now we do. */
9153 }
9156 {
9157 /* We had some pack expansion arguments that will only work if the packs
9158 are empty, but wait until instantiation time to complain.
9159 See variadic-ttp3.C. */
9161 /* Except that we can't provide empty packs to alias templates or
9162 concepts when there are no corresponding parameters. Basically,
9163 we can get here with this:
9165 template<typename T> concept C = true;
9167 template<typename... Args>
9168 requires C<Args...>
9169 void f();
9171 When parsing C<Args...>, we try to form a concept check of
9172 C<?, Args...>. Without the extra check for substituting an empty
9173 pack past the last parameter, we can accept the check as valid.
9175 FIXME: This may be valid for alias templates (but I doubt it).
9177 FIXME: The error could be better also. */
9179 {
9184 }
9195 }
9198 {
9201 }
9208 }
9210 /* Convert all template arguments to their appropriate types, and
9211 return a vector containing the innermost resulting template
9212 arguments. If any error occurs, return error_mark_node. Error and
9213 warning messages are not issued.
9215 Note that no function argument deduction is performed, and default
9216 arguments are used to fill in unspecified arguments. */
9217 tree
9219 {
9221 }
9223 /* Convert all template arguments to their appropriate type, and
9224 instantiate default arguments as needed. This returns a vector
9225 containing the innermost resulting template arguments, or
9226 error_mark_node if unsuccessful. */
9227 tree
9229 tsubst_flags_t complain)
9230 {
9232 }
9234 /* Like coerce_template_parms. If PARMS represents all template
9235 parameters levels, this function returns a vector of vectors
9236 representing all the resulting argument levels. Note that in this
9237 case, only the innermost arguments are coerced because the
9238 outermost ones are supposed to have been coerced already.
9240 Otherwise, if PARMS represents only (the innermost) vector of
9241 parameters, this function returns a vector containing just the
9242 innermost resulting arguments. */
9244 static tree
9246 tree args,
9247 tree in_decl,
9248 tsubst_flags_t complain,
9251 {
9254 tree coerced_args;
9257 {
9259 tree level;
9265 {
9266 tree l;
9270 require_all_args,
9271 use_default_args);
9272 else
9279 }
9280 }
9281 else
9284 require_all_args,
9285 use_default_args);
9287 }
9289 /* Returns true if T is a wrapper to make a C++20 template parameter
9290 object const. */
9292 static bool
9294 {
9300 }
9302 /* Returns 1 if template args OT and NT are equivalent. */
9304 int
9306 {
9319 /* DR 1558: Don't treat an alias template specialization with dependent
9320 arguments as equivalent to its underlying type when used as a template
9321 argument; we need them to be distinct so that we substitute into the
9322 specialization arguments at instantiation time. And aliases can't be
9323 equivalent without being ==, so we don't need to look any deeper.
9325 During partial ordering, however, we need to treat them normally so we can
9326 order uses of the same alias with different cv-qualification (79960). */
9332 /* For member templates */
9345 {
9349 }
9350 else
9351 {
9352 /* Try to treat a template non-type argument that has been converted
9353 to the parameter type as equivalent to one that hasn't yet. */
9367 }
9368 }
9370 /* Returns true iff the OLDARGS and NEWARGS are in fact identical sets of
9371 template arguments. Returns false otherwise, and updates OLDARG_PTR and
9372 NEWARG_PTR with the offending arguments if they are non-NULL. */
9374 bool
9378 {
9389 {
9394 {
9400 }
9401 }
9403 }
9407 {
9409 }
9411 /* Implement a freelist interface for objects of type T.
9413 Head is a separate object, rather than a regular member, so that we
9414 can define it as a GTY deletable pointer, which is highly
9415 desirable. A data member could be declared that way, but then the
9416 containing object would implicitly get GTY((user)), which would
9417 prevent us from instantiating freelists as global objects.
9418 Although this way we can create freelist global objects, they're
9419 such thin wrappers that instantiating temporaries at every use
9420 loses nothing and saves permanent storage for the freelist object.
9422 Member functions next, anew, poison and reinit have default
9423 implementations that work for most of the types we're interested
9424 in, but if they don't work for some type, they should be explicitly
9425 specialized. See the comments before them for requirements, and
9426 the example specializations for the tree_list_freelist. */
9428 class freelist
9429 {
9430 /* Return the next object in a chain. We could just do type
9431 punning, but if we access the object with its underlying type, we
9432 avoid strict-aliasing trouble. This needs only work between
9433 poison and reinit. */
9436 /* Return a newly allocated, uninitialized or minimally-initialized
9437 object of type T. Any initialization performed by anew should
9438 either remain across the life of the object and the execution of
9439 poison, or be redone by reinit. */
9442 /* Optionally scribble all over the bits holding the object, so that
9443 they become (mostly?) uninitialized memory. This is called while
9444 preparing to make the object part of the free list. */
9449 #ifdef ENABLE_GC_CHECKING
9450 /* Poison the data, to indicate the data is garbage. */
9453 #endif
9454 /* Let valgrind know the object is free. */
9457 /* Let valgrind know the next portion of the object is available,
9458 but uninitialized. */
9460 }
9462 /* Bring an object that underwent at least one lifecycle after anew
9463 and before the most recent free and poison, back to a usable
9464 state, reinitializing whatever is needed for it to be
9465 functionally equivalent to an object just allocated and returned
9466 by anew. This may poison or clear the next field, used by
9467 freelist housekeeping after poison was called. */
9471 #ifdef ENABLE_GC_CHECKING
9473 #endif
9474 /* Let valgrind know the entire object is available, but
9475 uninitialized. */
9477 }
9479 /* Reference a GTY-deletable pointer that points to the first object
9480 in the free list proper. */
9483 /* Construct a freelist object chaining objects off of HEAD. */
9486 /* Add OBJ to the free object list. The former head becomes OBJ's
9487 successor. */
9489 {
9493 }
9495 /* Take an object from the free list, if one is available, or
9496 allocate a new one. Objects taken from the free list should be
9497 regarded as filled with garbage, except for bits that are
9498 configured to be preserved across free and alloc. */
9500 {
9502 {
9507 }
9508 else
9510 }
9511 };
9513 /* Explicitly specialize the interfaces for freelist<tree_node>: we
9514 want to allocate a TREE_LIST using the usual interface, and ensure
9515 TREE_CHAIN remains functional. Alas, we have to duplicate a bit of
9516 build_tree_list logic in reinit, so this could go out of sync. */
9520 {
9522 }
9524 inline tree
9526 {
9528 }
9532 {
9538 #ifdef ENABLE_GC_CHECKING
9541 /* Poison the data, to indicate the data is garbage. */
9544 #endif
9545 /* Let valgrind know the object is free. */
9547 /* But we still want to use the TREE_CODE and TREE_CHAIN parts. */
9551 #ifdef ENABLE_GC_CHECKING
9553 /* Keep TREE_CHAIN functional. */
9555 #else
9557 #endif
9558 }
9562 {
9565 #ifdef ENABLE_GC_CHECKING
9569 #endif
9571 /* Let valgrind know the entire object is available, but
9572 uninitialized. */
9575 #ifdef ENABLE_GC_CHECKING
9577 #else
9579 #endif
9580 }
9582 /* Point to the first object in the TREE_LIST freelist. */
9584 /* Return the/an actual TREE_LIST freelist. */
9587 {
9589 }
9591 /* Point to the first object in the tinst_level freelist. */
9593 /* Return the/an actual tinst_level freelist. */
9596 {
9598 }
9600 /* Point to the first object in the pending_template freelist. */
9602 /* Return the/an actual pending_template freelist. */
9605 {
9607 }
9609 /* Build the TREE_LIST object out of a split list, store it
9610 permanently, and return it. */
9611 tree
9613 {
9622 }
9626 /* Increment OBJ's refcount unless it is already infinite. */
9629 {
9633 }
9635 /* Release storage for OBJ and node, if it's a TREE_LIST. */
9636 void
9638 {
9642 }
9644 /* Decrement OBJ's refcount if not infinite. If it reaches zero, release
9645 OBJ's DECL and OBJ, and start over with the tinst_level object that
9646 used to be referenced by OBJ's NEXT. */
9647 static void
9649 {
9653 {
9657 }
9658 }
9660 /* Modify PTR so that it points to OBJ, adjusting the refcounts of OBJ
9661 and of the former PTR. Omitting the second argument is equivalent
9662 to passing (T*)NULL; this is allowed because passing the
9663 zero-valued integral constant NULL confuses type deduction and/or
9664 overload resolution. */
9666 static void
9668 {
9672 }
9674 static void
9676 {
9686 /* We are called both from instantiate_decl, where we've already had a
9687 tinst_level pushed, and instantiate_template, where we haven't.
9688 Compensate. */
9690 level = !current_tinst_level
9702 else
9711 }
9714 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
9715 ARGLIST. Valid choices for FNS are given in the cp-tree.def
9716 documentation for TEMPLATE_ID_EXPR. */
9718 tree
9720 {
9727 {
9730 }
9733 {
9736 unknown_type_node,
9738 arglist);
9740 }
9743 }
9745 /* Within the scope of a template class S<T>, the name S gets bound
9746 (in build_self_reference) to a TYPE_DECL for the class, not a
9747 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
9748 or one of its enclosing classes, and that type is a template,
9749 return the associated TEMPLATE_DECL. Otherwise, the original
9750 DECL is returned.
9752 Also handle the case when DECL is a TREE_LIST of ambiguous
9753 injected-class-names from different bases. */
9755 tree
9757 {
9761 /* DR 176: A lookup that finds an injected-class-name (10.2
9762 [class.member.lookup]) can result in an ambiguity in certain cases
9763 (for example, if it is found in more than one base class). If all of
9764 the injected-class-names that are found refer to specializations of
9765 the same class template, and if the name is followed by a
9766 template-argument-list, the reference refers to the class template
9767 itself and not a specialization thereof, and is not ambiguous. */
9769 {
9772 {
9778 }
9781 else
9783 }
9789 }
9791 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
9792 parameters, find the desired type.
9794 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
9796 IN_DECL, if non-NULL, is the template declaration we are trying to
9797 instantiate.
9799 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
9800 the class we are looking up.
9802 Issue error and warning messages under control of COMPLAIN.
9804 If the template class is really a local class in a template
9805 function, then the FUNCTION_CONTEXT is the function in which it is
9806 being instantiated.
9808 ??? Note that this function is currently called *twice* for each
9809 template-id: the first time from the parser, while creating the
9810 incomplete type (finish_template_type), and the second type during the
9811 real instantiation (instantiate_template_class). This is surely something
9812 that we want to avoid. It also causes some problems with argument
9813 coercion (see convert_nontype_argument for more information on this). */
9815 tree
9818 {
9822 tree t;
9825 spec_entry elt;
9826 hashval_t hash;
9829 {
9833 else
9834 {
9841 }
9844 }
9846 {
9849 /* If we are declaring a constructor, say A<T>::A<T>, we will get
9850 an implicit typename for the second A. Deal with it. */
9855 {
9858 }
9859 }
9862 {
9865 }
9867 {
9871 }
9873 {
9876 }
9878 /* Issue an error message if we didn't find a template. */
9880 {
9884 }
9887 /* Make sure it's a user visible template, if it was named by
9888 the user. */
9891 {
9893 {
9897 }
9899 }
9903 /* An alias that just changes the name of a template is equivalent to the
9904 other template, so if any of the arguments are pack expansions, strip
9905 the alias to avoid problems with a pack expansion passed to a non-pack
9906 alias template parameter (DR 1430). */
9911 {
9912 tree parm;
9921 }
9922 else
9923 {
9925 tree gen_tmpl;
9926 tree type_decl;
9934 /* An error occurred while building the template TEMPL, and a
9935 diagnostic has most certainly been emitted for that
9936 already. Let's propagate that error. */
9948 {
9949 /* We've been given an incomplete set of template arguments.
9950 For example, given:
9952 template <class T> struct S1 {
9953 template <class U> struct S2 {};
9954 template <class U> struct S2<U*> {};
9955 };
9957 we will be called with an ARGLIST of `U*', but the
9958 TEMPLATE will be `template <class T> template
9959 <class U> struct S1<T>::S2'. We must fill in the missing
9960 arguments. */
9964 }
9966 /* Now we should have enough arguments. */
9969 /* From here on, we're only interested in the most general
9970 template. */
9972 /* Shortcut looking up the current class scope again. */
9979 /* Calculate the BOUND_ARGS. These will be the args that are
9980 actually tsubst'd into the definition to create the
9981 instantiation. */
9983 complain,
9988 /* We were unable to bind the arguments. */
9991 /* In the scope of a template class, explicit references to the
9992 template class refer to the type of the template, not any
9993 instantiation of it. For example, in:
9995 template <class T> class C { void f(C<T>); }
9997 the `C<T>' is just the same as `C'. Outside of the
9998 class, however, such a reference is an instantiation. */
10002 {
10007 }
10009 /* If we already have this specialization, return it. */
10019 /* If the template's constraints are not satisfied,
10020 then we cannot form a valid type.
10022 Note that the check is deferred until after the hash
10023 lookup. This prevents redundant checks on previously
10024 instantiated specializations. */
10028 {
10030 {
10031 auto_diagnostic_group d;
10034 }
10036 }
10040 /* If the deduced arguments are invalid, then the binding
10041 failed. */
10045 complain))
10052 /* This occurs when the user has tried to define a tagged type
10053 in a scope that forbids it. We emitted an error during the
10054 parse. We didn't complete the bail out then, so here we
10055 are. */
10060 {
10063 }
10064 else
10073 /* Create the type. */
10075 {
10076 /* The user referred to a specialization of an alias
10077 template represented by GEN_TMPL.
10079 [temp.alias]/2 says:
10081 When a template-id refers to the specialization of an
10082 alias template, it is equivalent to the associated
10083 type obtained by substitution of its
10084 template-arguments for the template-parameters in the
10085 type-id of the alias template. */
10088 /* Note that the call above (by indirectly calling
10089 register_specialization in tsubst_decl) registers the
10090 TYPE_DECL representing the specialization of the alias
10091 template. So next time someone substitutes ARGLIST for
10092 the template parms into the alias template (GEN_TMPL),
10093 she'll get that TYPE_DECL back. */
10097 }
10099 {
10101 {
10112 }
10113 else
10114 {
10115 /* We don't want to call start_enum for this type, since
10116 the values for the enumeration constants may involve
10117 template parameters. And, no one should be interested
10118 in the enumeration constants for such a type. */
10121 }
10125 }
10127 {
10128 /* Lambda closures are regenerated in tsubst_lambda_expr, not
10129 instantiated here. */
10137 /* A local class. Make sure the decl gets registered properly. */
10144 /* This instantiation is another name for the primary
10145 template type. Set the TYPE_CANONICAL field
10146 appropriately. */
10150 }
10151 else
10154 /* If we called start_enum or pushtag above, this information
10155 will already be set up. */
10158 {
10165 }
10168 /* Although GEN_TMPL is the TEMPLATE_DECL, it has the same value
10169 of export flag. We want to propagate this because it might
10170 be a friend declaration that pushes a new hidden binding. */
10174 {
10180 {
10183 }
10184 }
10188 {
10192 {
10193 tree attributes
10201 }
10202 }
10204 /* Let's consider the explicit specialization of a member
10205 of a class template specialization that is implicitly instantiated,
10206 e.g.:
10207 template<class T>
10208 struct S
10209 {
10210 template<class U> struct M {}; //#0
10211 };
10213 template<>
10214 template<>
10215 struct S<int>::M<char> //#1
10216 {
10217 int i;
10218 };
10219 [temp.expl.spec]/4 says this is valid.
10221 In this case, when we write:
10222 S<int>::M<char> m;
10224 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
10225 the one of #0.
10227 When we encounter #1, we want to store the partial instantiation
10228 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
10230 For all cases other than this "explicit specialization of member of a
10231 class template", we just want to store the most general template into
10232 the CLASSTYPE_TI_TEMPLATE of M.
10234 This case of "explicit specialization of member of a class template"
10235 only happens when:
10236 1/ the enclosing class is an instantiation of, and therefore not
10237 the same as, the context of the most general template, and
10238 2/ we aren't looking at the partial instantiation itself, i.e.
10239 the innermost arguments are not the same as the innermost parms of
10240 the most general template.
10242 So it's only when 1/ and 2/ happens that we want to use the partial
10243 instantiation of the member template in lieu of its most general
10244 template. */
10248 /* the enclosing class must be an instantiation... */
10251 {
10255 tree partial_inst_args =
10262 use_partial_inst_tmpl =
10263 /*...and we must not be looking at the partial instantiation
10264 itself. */
10266 partial_inst_args);
10267 }
10270 /* This case is easy; there are no member templates involved. */
10272 else
10273 {
10274 /* This is a full instantiation of a member template. Find
10275 the partial instantiation of which this is an instance. */
10277 /* Temporarily reduce by one the number of levels in the ARGLIST
10278 so as to avoid comparing the last set of arguments. */
10280 /* We don't use COMPLAIN in the following call because this isn't
10281 the immediate context of deduction. For instance, tf_partial
10282 could be set here as we might be at the beginning of template
10283 argument deduction when any explicitly specified template
10284 arguments are substituted into the function type. tf_partial
10285 could lead into trouble because we wouldn't find the partial
10286 instantiation that might have been created outside tf_partial
10287 context, because the levels of template parameters wouldn't
10288 match, because in a tf_partial context, tsubst doesn't reduce
10289 TEMPLATE_PARM_LEVEL. */
10292 /* FOUND is either a proper class type, or an alias
10293 template specialization. In the later case, it's a
10294 TYPE_DECL, resulting from the substituting of arguments
10295 for parameters in the TYPE_DECL of the alias template
10296 done earlier. So be careful while getting the template
10297 of FOUND. */
10299 ? found
10306 {
10307 /* If this partial instantiation is specialized, we want to
10308 use it for hash table lookup. */
10312 }
10313 }
10315 /* Build template info for the new specialization. */
10325 /* Note this use of the partial instantiation so we can check it
10326 later in maybe_process_partial_specialization. */
10334 /* Now that the type has been registered on the instantiations
10335 list, we set up the enumerators. Because the enumeration
10336 constants may involve the enumeration type itself, we make
10337 sure to register the type first, and then create the
10338 constants. That way, doing tsubst_expr for the enumeration
10339 constants won't result in recursive calls here; we'll find
10340 the instantiation and exit above. */
10344 /* If the type makes use of template parameters, the
10345 code that generates debugging information will crash. */
10348 /* Possibly limit visibility based on template args. */
10355 }
10356 }
10358 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
10360 tree
10362 {
10366 /* The type of the expression is NULL_TREE since the template-id could refer
10367 to an explicit or partial specialization. */
10369 }
10371 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
10373 tree
10375 {
10387 {
10389 {
10390 auto_diagnostic_group d;
10393 }
10395 }
10398 }
10400 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
10401 TARGS template args, and instantiate it if it's not dependent. */
10403 tree
10405 tsubst_flags_t complain)
10406 {
10409 {
10412 }
10415 }
10417 /* If the set of template parameters PARMS contains a template parameter
10418 at the given LEVEL and INDEX, then return this parameter. Otherwise
10419 return NULL_TREE. */
10421 static tree
10423 {
10432 /* As in template_parm_to_arg. */
10435 else
10440 }
10442 /* Return the template parameter from PARMS that positionally corresponds
10443 to the template parameter PARM, or else return NULL_TREE. */
10445 static tree
10447 {
10451 }
10453 \f
10454 struct pair_fn_data
10455 {
10456 tree_fn_t fn;
10457 tree_fn_t any_fn;
10459 /* True when we should also visit template parameters that occur in
10460 non-deduced contexts. */
10463 };
10465 /* Called from for_each_template_parm via walk_tree. */
10467 static tree
10469 {
10476 #define WALK_SUBTREE(NODE) \
10477 do \
10478 { \
10479 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
10480 pfd->include_nondeduced_p, \
10481 pfd->any_fn); \
10482 if (result) goto out; \
10483 } \
10484 while (0)
10494 {
10498 /* Fall through. */
10504 else
10514 /* Since we're not going to walk subtrees, we have to do this
10515 explicitly here. */
10517 /* Fall through. */
10520 /* Check the return type. */
10523 /* Check the parameter types. Since default arguments are not
10524 instantiated until they are needed, the TYPE_ARG_TYPES may
10525 contain expressions that involve template parameters. But,
10526 no-one should be looking at them yet. And, once they're
10527 instantiated, they don't contain template parameters, so
10528 there's no point in looking at them then, either. */
10529 {
10530 tree parm;
10535 /* Since we've already handled the TYPE_ARG_TYPES, we don't
10536 want walk_tree walking into them itself. */
10538 }
10541 {
10545 }
10564 /* Fall through. */
10576 /* Record template parameters such as `T' inside `TT<T>'. */
10578 /* Fall through. */
10590 /* A template template parameter is encountered. */
10594 /* Already substituted template template parameter */
10599 /* A template-id in a TYPENAME_TYPE might be a deduced context after
10600 partial instantiation. */
10607 /* If there's no type, then this thing must be some expression
10608 involving template parameters. */
10618 /* These are non-deduced contexts. */
10639 {
10643 /* Recursively walk the type of each constraint variable. */
10646 {
10649 }
10650 }
10655 }
10657 #undef WALK_SUBTREE
10659 /* We didn't find any template parameters we liked. */
10660 out:
10662 }
10664 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
10665 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
10666 call FN with the parameter and the DATA.
10667 If FN returns nonzero, the iteration is terminated, and
10668 for_each_template_parm returns 1. Otherwise, the iteration
10669 continues. If FN never returns a nonzero value, the value
10670 returned by for_each_template_parm is 0. If FN is NULL, it is
10671 considered to be the function which always returns 1.
10673 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
10674 parameters that occur in non-deduced contexts. When false, only
10675 visits those template parameters that can be deduced. */
10677 static tree
10681 tree_fn_t any_fn)
10682 {
10684 tree result;
10686 /* Set up. */
10692 /* Walk the tree. (Conceptually, we would like to walk without
10693 duplicates, but for_each_template_parm_r recursively calls
10694 for_each_template_parm, so we would need to reorganize a fair
10695 bit to use walk_tree_without_duplicates, so we keep our own
10696 visited list.) */
10699 else
10702 for_each_template_parm_r,
10706 /* Clean up. */
10708 {
10711 }
10714 }
10716 struct find_template_parameter_info
10717 {
10722 {}
10726 tree parm_list;
10727 tree ctx_parms;
10729 };
10731 /* Appends the declaration of T to the list in DATA. */
10733 static int
10735 {
10738 /* Template parameters declared within the expression are not part of
10739 the parameter mapping. For example, in this concept:
10741 template<typename T>
10742 concept C = requires { <expr> } -> same_as<int>;
10744 the return specifier same_as<int> declares a new decltype parameter
10745 that must not be part of the parameter mapping. The same is true
10746 for generic lambda parameters, lambda template parameters, etc. */
10754 /* We want the underlying TEMPLATE_TEMPLATE_PARM, not the
10755 BOUND_TEMPLATE_TEMPLATE_PARM itself. */
10758 /* This template parameter might be an argument to a cached dependent
10759 specalization that was formed earlier inside some other template, in
10760 which case the parameter is not among the ones that are in-scope.
10761 Look in CTX_PARMS to find the corresponding in-scope template
10762 parameter, and use it instead. */
10766 /* Arguments like const T yield parameters like const T. This means that
10767 a template-id like X<T, const T> would yield two distinct parameters:
10768 T and const T. Adjust types to their unqualified versions. */
10774 /* Verify the parameter we found has a valid index. */
10776 {
10782 }
10785 }
10787 /* Ensure that we recursively examine certain terms that are not normally
10788 visited in for_each_template_parm_r. */
10790 static int
10792 {
10795 #define WALK_SUBTREE(NODE) \
10796 do \
10797 { \
10798 for_each_template_parm (NODE, keep_template_parm, data, \
10799 &ftpi->visited, true, \
10800 any_template_parm_r); \
10801 } \
10802 while (0)
10804 /* A mention of a member alias/typedef is a use of all of its template
10805 arguments, including those from the enclosing class, so we don't use
10806 alias_template_specialization_p here. */
10812 {
10814 /* Type constraints of a placeholder type may contain parameters. */
10821 /* Search through references to variable templates. */
10828 /* A parameter or constraint variable may also depend on a template
10829 parameter without explicitly naming it. */
10834 /* If T is a member template that shares template parameters with
10835 ctx_parms, we need to mark all those parameters for mapping.
10836 To that end, it should suffice to just walk the DECL_CONTEXT of
10837 the template (assuming the template is not overly general). */
10842 {
10843 /* Look in the parms and body. */
10847 }
10852 /* The conversion-type-id of a conversion operator may be dependent. */
10863 }
10865 /* Keep walking. */
10867 }
10869 /* Returns a list of unique template parameters found within T, where CTX_PARMS
10870 are the template parameters in scope. */
10872 tree
10874 {
10882 }
10884 /* Returns true if T depends on any template parameter. */
10886 bool
10888 {
10892 /* Namespaces can't depend on any template parameters. */
10908 else
10910 }
10912 /* Returns true iff we're processing an incompletely instantiated function
10913 template. Useful instead of processing_template_decl because the latter
10914 is set to 0 during instantiate_non_dependent_expr. */
10916 bool
10918 {
10919 /* Inspect the less volatile cfun->decl instead of current_function_decl;
10920 the latter might get set for e.g. access checking during satisfaction. */
10929 }
10931 /* Returns true if T depends on any template parameter with level LEVEL. */
10933 bool
10935 {
10938 }
10940 /* Returns true if the signature of DECL depends on any template parameter from
10941 its enclosing class. */
10943 bool
10945 {
10954 {
10957 {
10962 template_parm_outer_level,
10972 }
10973 }
10981 }
10983 /* Returns TRUE iff INST is an instantiation we don't need to do in an
10984 ill-formed translation unit, i.e. a variable or function that isn't
10985 usable in a constant expression. */
10989 {
10995 }
10997 /* Returns TRUE iff we should refuse to instantiate DECL because it's
10998 neglectable and instantiated from within an erroneous instantiation. */
11000 static bool
11002 {
11008 /* Avoid instantiating members of an ill-formed class. */
11009 bool refuse
11014 {
11019 }
11022 {
11023 /* Don't warn about it not being defined. */
11025 tree clone;
11028 }
11030 }
11038 /* We're starting to instantiate D; record the template instantiation context
11039 at LOC for diagnostics and to restore it later. */
11041 bool
11043 {
11047 {
11048 /* Tell error.cc not to try to instantiate any templates. */
11051 "template instantiation depth exceeds maximum of %d"
11053 max_tinst_depth);
11055 }
11057 /* If the current instantiation caused problems, don't let it instantiate
11058 anything else. Do allow deduction substitution and decls usable in
11059 constant expressions. */
11061 {
11062 /* Avoid no_linkage_errors and unused function (and all other)
11063 warnings for this decl. */
11066 }
11068 /* When not -quiet, dump template instantiations other than functions, since
11069 announce_function will take care of those. */
11091 }
11093 /* We're starting substitution of TMPL<ARGS>; record the template
11094 substitution context for diagnostics and to restore it later. */
11096 bool
11098 {
11100 }
11102 /* We're starting to instantiate D; record INPUT_LOCATION and the
11103 template instantiation context for diagnostics and to restore it
11104 later. */
11106 bool
11108 {
11110 }
11112 /* Likewise, but record LOC as the program location. */
11114 bool
11116 {
11119 }
11121 /* We're done instantiating this template; return to the instantiation
11122 context. */
11124 void
11126 {
11127 /* Restore the filename and line number stashed away when we started
11128 this instantiation. */
11132 }
11134 /* We're instantiating a deferred template; restore the template
11135 instantiation context in which the instantiation was requested, which
11136 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
11138 static tree
11140 {
11152 }
11154 /* Returns the TINST_LEVEL which gives the original instantiation
11155 context. */
11159 {
11165 }
11167 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
11168 vector of template arguments, as for tsubst.
11170 Returns an appropriate tsubst'd friend declaration. */
11172 static tree
11174 {
11175 tree new_friend;
11180 /* This was a friend declared with an explicit template
11181 argument list, e.g.:
11183 friend void f<>(T);
11185 to indicate that f was a template instantiation, not a new
11186 function declaration. Now, we have to figure out what
11187 instantiation of what template. */
11188 {
11190 tree new_args;
11191 tree tmpl;
11194 /* Friend functions are looked up in the containing namespace scope.
11195 We must enter that scope, to avoid finding member functions of the
11196 current class with same name. */
11211 tsk_none);
11213 }
11219 /* The NEW_FRIEND will look like an instantiation, to the
11220 compiler, but is not an instantiation from the point of view of
11221 the language. For example, we might have had:
11223 template <class T> struct S {
11224 template <class U> friend void f(T, U);
11225 };
11227 Then, in S<int>, template <class U> void f(int, U) is not an
11228 instantiation of anything. */
11232 {
11238 /* Substitute TEMPLATE_PARMS_CONSTRAINTS so that parameter levels will
11239 match in decls_match. */
11244 }
11246 /* The mangled name for the NEW_FRIEND is incorrect. The function
11247 is not a template instantiation and should not be mangled like
11248 one. Therefore, we forget the mangling here; we'll recompute it
11249 later if we need it. */
11251 {
11254 }
11257 {
11258 tree old_decl;
11259 tree ns;
11261 /* We must save some information from NEW_FRIEND before calling
11262 duplicate decls since that function will free NEW_FRIEND if
11263 possible. */
11273 {
11274 /* This declaration is a `primary' template. */
11279 }
11281 /* Inside pushdecl_namespace_level, we will push into the
11282 current namespace. However, the friend function should go
11283 into the namespace of the template. */
11293 {
11294 /* This new friend declaration matched an existing
11295 declaration. For example, given:
11297 template <class T> void f(T);
11298 template <class U> class C {
11299 template <class T> friend void f(T) {}
11300 };
11302 the friend declaration actually provides the definition
11303 of `f', once C has been instantiated for some type. So,
11304 old_decl will be the out-of-class template declaration,
11305 while new_friend is the in-class definition.
11307 But, if `f' was called before this point, the
11308 instantiation of `f' will have DECL_TI_ARGS corresponding
11309 to `T' but not to `U', references to which might appear
11310 in the definition of `f'. Previously, the most general
11311 template for an instantiation of `f' was the out-of-class
11312 version; now it is the in-class version. Therefore, we
11313 run through all specialization of `f', adding to their
11314 DECL_TI_ARGS appropriately. In particular, they need a
11315 new set of outer arguments, corresponding to the
11316 arguments for this class instantiation.
11318 The same situation can arise with something like this:
11320 friend void f(int);
11321 template <class T> class C {
11322 friend void f(T) {}
11323 };
11325 when `C<int>' is instantiated. Now, `f(int)' is defined
11326 in the class. */
11329 /* On the other hand, if the in-class declaration does
11330 *not* provide a definition, then we don't want to alter
11331 existing definitions. We can just leave everything
11332 alone. */
11333 ;
11334 else
11335 {
11339 /* Overwrite whatever template info was there before, if
11340 any, with the new template information pertaining to
11341 the declaration. */
11345 {
11346 /* We should have called reregister_specialization in
11347 duplicate_decls. */
11352 /* Instantiate it if the global has already been used. */
11356 }
11357 else
11358 {
11359 tree t;
11361 /* Indicate that the old function template is a partial
11362 instantiation. */
11370 /* Reassign any specializations already in the hash table
11371 to the new more general template, and add the
11372 additional template args. */
11376 {
11378 spec_entry elt;
11390 register_specialization
11393 }
11395 }
11396 }
11398 /* The information from NEW_FRIEND has been merged into OLD_DECL
11399 by duplicate_decls. */
11401 }
11402 }
11403 else
11404 {
11408 /* In the code
11409 template <class T> class C {
11410 template <class U> friend void C1<U>::f (); // case 1
11411 friend void C2<T>::f (); // case 2
11412 };
11413 we only need to make sure CONTEXT is a complete type for
11414 case 2. To distinguish between the two cases, we note that
11415 CONTEXT of case 1 remains dependent type after tsubst while
11416 this isn't true for case 2. */
11426 {
11428 /* do_friend adds the TEMPLATE_DECL for any member friend
11429 template even if it isn't a member template, i.e.
11430 template <class T> friend A<T>::f();
11431 Look through it in that case. */
11435 /* Check to see that the declaration is really present, and,
11436 possibly obtain an improved declaration. */
11441 }
11442 }
11445 }
11447 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
11448 template arguments, as for tsubst.
11450 Returns an appropriate tsubst'd friend type or error_mark_node on
11451 failure. */
11453 static tree
11455 {
11456 tree tmpl;
11459 {
11462 }
11467 else
11468 {
11471 }
11477 {
11478 /* The friend template has already been declared. Just
11479 check to see that the declarations match, and install any new
11480 default parameters. We must tsubst the default parameters,
11481 of course. We only need the innermost template parameters
11482 because that is all that redeclare_class_template will look
11483 at. */
11486 {
11494 }
11495 }
11496 else
11497 {
11498 /* The friend template has not already been declared. In this
11499 case, the instantiation of the template class will cause the
11500 injection of this template into the namespace scope. */
11504 {
11505 /* The new TMPL is not an instantiation of anything, so we
11506 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
11507 for the new type because that is supposed to be the
11508 corresponding template decl, i.e., TMPL. */
11515 /* Substitute into and set the constraints on the new declaration. */
11517 {
11523 }
11525 /* Inject this template into the enclosing namspace scope. */
11527 }
11528 }
11532 else
11536 }
11538 /* Returns zero if TYPE cannot be completed later due to circularity.
11539 Otherwise returns one. */
11541 static int
11543 {
11553 else
11555 }
11560 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
11561 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
11563 static tree
11566 {
11575 {
11582 clauses
11586 else
11588 }
11592 {
11594 tree varid
11605 {
11609 {
11611 {
11619 }
11620 else
11621 {
11625 {
11626 bool allow_string
11638 {
11639 location_t loc
11641 match_loc);
11647 "integer expression or string "
11649 else
11653 }
11656 {
11657 location_t loc
11659 match_loc);
11663 }
11665 }
11666 }
11667 }
11668 }
11670 }
11671 /* If the first attribute argument is an identifier, don't
11672 pass it through tsubst. Attributes like mode, format,
11673 cleanup and several target specific attributes expect it
11674 unmodified. */
11676 {
11677 tree chain
11682 }
11684 {
11685 /* An attribute pack expansion. */
11694 {
11698 }
11700 }
11701 else
11710 }
11712 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
11713 unchanged or a new TREE_LIST chain. */
11715 static tree
11718 {
11723 {
11727 }
11731 {
11734 {
11737 {
11743 }
11744 }
11746 }
11749 }
11751 /* Apply any attributes which had to be deferred until instantiation
11752 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
11753 ARGS, COMPLAIN, IN_DECL are as tsubst. Returns true normally,
11754 false on error. */
11756 static bool
11759 {
11760 tree t;
11767 {
11771 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
11772 to our attributes parameter. */
11774 }
11775 else
11776 {
11778 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
11779 lookup_template_class_1, and should be preserved. */
11783 }
11785 /* save_template_attributes puts the dependent attributes at the beginning of
11786 the list; find the non-dependent ones. */
11792 /* Apply any non-dependent attributes. */
11798 /* And then any dependent ones. */
11802 {
11807 {
11810 }
11813 }
11815 /* cplus_decl_attributes can add some attributes implicitly. For templates,
11816 those attributes should have been added already when those templates were
11817 parsed, and shouldn't be added based on from which context they are
11818 first time instantiated. */
11821 optimization_default_node);
11824 NULL);
11829 }
11831 /* The template TMPL is being instantiated with the template arguments TARGS.
11832 Perform the access checks that we deferred when parsing the template. */
11834 static void
11836 {
11846 {
11854 /* Make access check error messages point to the location
11855 of the use of the typedef. */
11859 }
11860 }
11862 tree
11864 {
11868 tree typedecl;
11869 tree pbinfo;
11870 tree base_list;
11872 tree fn_context;
11881 /* Figure out which template is being instantiated. */
11885 /* Mark the type as in the process of being defined. */
11888 /* We may be in the middle of deferred access check. Disable
11889 it now. */
11892 /* Determine what specialization of the original template to
11893 instantiate. */
11898 {
11899 /* This TYPE is actually an instantiation of a partial
11900 specialization. We replace the innermost set of ARGS with
11901 the arguments appropriate for substitution. For example,
11902 given:
11904 template <class T> struct S {};
11905 template <class T> struct S<T*> {};
11907 and supposing that we are instantiating S<int*>, ARGS will
11908 presently be {int*} -- but we need {int}. */
11911 }
11912 else
11913 {
11916 }
11918 /* If the template we're instantiating is incomplete, then clearly
11919 there's nothing we can do. */
11921 {
11922 /* We can try again later. */
11925 }
11927 /* If we've recursively instantiated too many templates, stop. */
11935 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
11940 else
11941 {
11944 }
11945 /* Use #pragma pack from the template context. */
11951 /* Set the input location to the most specialized template definition.
11952 This is needed if tsubsting causes an error. */
11966 {
11969 /* Adjust visibility for template arguments. */
11971 }
11977 /* We should never instantiate a nested class before its enclosing
11978 class; we need to look up the nested class by name before we can
11979 instantiate it, and that lookup should instantiate the enclosing
11980 class. */
11985 /* Defer access checking while we substitute into the types named in
11986 the base-clause. */
11989 {
11990 tree pbase_binfo;
11993 /* Substitute into each of the bases to determine the actual
11994 basetypes. */
11996 {
11997 tree base;
12003 {
12004 expanded_bases =
12011 }
12014 {
12016 /* Extract the already-expanded base class. */
12018 else
12019 /* Substitute to figure out the base class. */
12021 NULL_TREE);
12029 }
12030 }
12032 /* The list is now in reverse order; correct that. */
12034 }
12035 /* Now call xref_basetypes to set up all the base-class
12036 information. */
12044 /* Now that our base classes are set up, enter the scope of the
12045 class, so that name lookups into base classes, etc. will work
12046 correctly. This is precisely analogous to what we do in
12047 begin_class_definition when defining an ordinary non-template
12048 class, except we also need to push the enclosing classes. */
12051 /* Now check accessibility of the types named in its base-clause,
12052 relative to the scope of the class. */
12055 /* A vector to hold members marked with attribute used. */
12058 /* Now members are processed in the order of declaration. */
12061 {
12065 {
12067 {
12069 /* A closure type for a lambda in an NSDMI or default argument.
12070 Ignore it; it will be regenerated when needed. */
12077 /* If the member is a class template, then -- even after
12078 substitution -- there may be dependent types in the
12079 template argument list for the class. We increment
12080 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
12081 that function will assume that no types are dependent
12082 when outside of a template. */
12092 {
12096 /* Unfortunately, lookup_template_class sets
12097 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
12098 instantiation (i.e., for the type of a member
12099 template class nested within a template class.)
12100 This behavior is required for
12101 maybe_process_partial_specialization to work
12102 correctly, but is not accurate in this case;
12103 the TAG is not an instantiation of anything.
12104 (The corresponding TEMPLATE_DECL is an
12105 instantiation, but the TYPE is not.) */
12108 /* Now, install the tag. We don't use pushtag
12109 because that does too much work -- creating an
12110 implicit typedef, which we've already done. */
12115 }
12116 }
12118 {
12119 tree r;
12128 /* Instantiate members marked with attribute used. */
12134 }
12137 /* A closure type for a lambda in an NSDMI or default argument.
12139 else
12140 {
12141 /* Build new TYPE_FIELDS. */
12146 {
12147 tree r;
12152 /* The file and line for this declaration, to
12153 assist in error message reporting. Since we
12154 called push_tinst_level above, we don't need to
12155 restore these. */
12165 {
12166 /* A capture pack became multiple fields. */
12169 }
12172 {
12176 {
12177 /* In [temp.inst]:
12179 [t]he initialization (and any associated
12180 side-effects) of a static data member does
12181 not occur unless the static data member is
12182 itself used in a way that requires the
12183 definition of the static data member to
12184 exist.
12186 Therefore, we do not substitute into the
12187 initialized for the static data member here. */
12188 finish_static_data_member_decl
12194 /* Instantiate members marked with attribute used. */
12197 }
12199 {
12200 /* Determine whether R has a valid type and can be
12201 completed later. If R is invalid, then its type
12202 is replaced by error_mark_node. */
12208 {
12209 /* If R's type couldn't be completed and
12210 it isn't a flexible array member (whose
12211 type is incomplete by definition) give
12212 an error. */
12215 }
12220 {
12223 }
12227 }
12229 /* If it is a TYPE_DECL for a class-scoped
12230 ENUMERAL_TYPE, such a thing will already have
12231 been added to the field list by tsubst_enum
12232 in finish_member_declaration case above. */
12236 {
12239 }
12240 }
12241 }
12242 }
12243 }
12244 else
12245 {
12248 {
12249 /* Build new CLASSTYPE_FRIEND_CLASSES. */
12253 {
12254 /* template <class T> friend class C; */
12256 }
12258 {
12259 /* template <class T> friend class C::D; */
12264 }
12267 {
12268 /* This could be either
12270 friend class T::C;
12272 when dependent_type_p is false or
12274 template <class U> friend class T::C;
12276 otherwise. */
12277 /* Bump processing_template_decl in case this is something like
12278 template <class T> friend struct A<T>::B. */
12283 }
12285 /* friend class C<T>; */
12289 /* Otherwise it's
12291 friend class C;
12293 where C is already declared or
12295 friend class C<int>;
12297 We don't have to do anything in these cases. */
12301 }
12302 else
12303 {
12304 /* Build new DECL_FRIENDLIST. */
12305 tree r;
12307 /* The file and line for this declaration, to
12308 assist in error message reporting. Since we
12309 called push_tinst_level above, we don't need to
12310 restore these. */
12314 {
12317 }
12322 {
12325 }
12326 }
12327 }
12328 }
12331 {
12332 /* Restore these before substituting into the lambda capture
12333 initializers. */
12336 }
12338 /* Set the file and line number information to whatever is given for
12339 the class itself. This puts error messages involving generated
12340 implicit functions at a predictable point, and the same point
12341 that would be used for non-template classes. */
12348 /* Remember if instantiating this class ran into errors, so we can avoid
12349 instantiating member functions in limit_bad_template_recursion. We set
12350 this flag even if the problem was in another instantiation triggered by
12351 this one, as that will likely also cause trouble for member functions. */
12355 /* We don't instantiate default arguments for member functions. 14.7.1:
12357 The implicit instantiation of a class template specialization causes
12358 the implicit instantiation of the declarations, but not of the
12359 definitions or default arguments, of the class member functions,
12360 member classes, static data members and member templates.... */
12365 /* Now that we've gone through all the members, instantiate those
12366 marked with attribute used. We must do this in the context of
12367 the class -- not the context we pushed from, as that might be
12368 inside a template and change the behaviour of mark_used. */
12378 /* The vtable for a template class can be emitted in any translation
12379 unit in which the class is instantiated. When there is no key
12380 method, however, finish_struct_1 will already have added TYPE to
12381 the keyed_classes. */
12386 }
12388 tree
12390 {
12391 tree r;
12397 else
12398 {
12405 }
12408 }
12410 /* Given a function parameter pack TMPL_PARM and some function parameters
12411 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
12412 and set *SPEC_P to point at the next point in the list. */
12414 tree
12416 {
12417 /* Collect all of the extra "packed" parameters into an
12418 argument pack. */
12419 tree argpack;
12430 {
12431 /* The instantiation is still a parameter pack; don't wrap it in a
12432 NONTYPE_ARGUMENT_PACK. */
12435 }
12436 else
12437 {
12438 /* Fill in PARMVEC with all of the parameters. */
12442 {
12448 }
12450 /* Build the argument packs. */
12452 }
12456 }
12458 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
12459 NONTYPE_ARGUMENT_PACK. */
12461 static tree
12463 {
12465 }
12467 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
12468 pack expansion with no extra args, 2 if it has extra args, or 0
12469 if it is not a pack expansion. */
12471 static int
12473 {
12475 /* We're being called before this happens in tsubst_pack_expansion. */
12482 /* A decl pack is itself an expansion. */
12489 }
12492 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
12494 static tree
12496 {
12503 }
12505 /* This is a subroutine of tsubst_pack_expansion.
12507 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
12508 mechanism to store the (non complete list of) arguments of the
12509 substitution and return a non substituted pack expansion, in order
12510 to wait for when we have enough arguments to really perform the
12511 substitution. */
12513 static bool
12515 tree parm_packs,
12518 {
12523 /* If one pack has an expansion and another pack has a normal
12524 argument or if one pack has an empty argument and an another
12525 one hasn't then tsubst_pack_expansion cannot perform the
12526 substitution and need to fall back on the
12527 PACK_EXPANSION_EXTRA mechanism. */
12531 {
12532 /* If all the actual packs are pack expansions, we can still
12533 subsitute directly. */
12535 {
12545 }
12547 }
12550 {
12554 parm_pack;
12556 {
12561 /* We can't substitute a pack expansion with extra args into
12562 our pattern. */
12566 else
12568 }
12571 {
12574 }
12575 }
12577 }
12579 /* [temp.variadic]/6 says that:
12581 The instantiation of a pack expansion [...]
12582 produces a list E1,E2, ..., En, where N is the number of elements
12583 in the pack expansion parameters.
12585 This subroutine of tsubst_pack_expansion produces one of these Ei.
12587 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
12588 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
12589 PATTERN, and each TREE_VALUE is its corresponding argument pack.
12590 INDEX is the index 'i' of the element Ei to produce. ARGS,
12591 COMPLAIN, and IN_DECL are the same parameters as for the
12592 tsubst_pack_expansion function.
12594 The function returns the resulting Ei upon successful completion,
12595 or error_mark_node.
12597 Note that this function possibly modifies the ARGS parameter, so
12598 it's the responsibility of the caller to restore it. */
12600 static tree
12602 tree parm_packs,
12604 tree args /* This parm gets
12606 tsubst_flags_t complain,
12607 tree in_decl)
12608 {
12609 tree t;
12612 /* For each parameter pack, change the substitution of the parameter
12613 pack to the ith argument in its argument pack, then expand the
12614 pattern. */
12616 {
12621 ith_elem_is_expansion |=
12624 /* Select the Ith argument from the pack. */
12628 {
12630 {
12635 }
12636 else
12638 }
12639 else
12640 {
12645 {
12647 /* Update the corresponding argument. */
12649 }
12650 else
12651 /* Re-use the ARGUMENT_PACK_SELECT. */
12653 }
12655 }
12657 /* Substitute into the PATTERN with the (possibly altered)
12658 arguments. */
12660 /* Expanding a fixed parameter pack from
12661 coerce_template_parameter_pack. */
12668 else
12669 {
12672 /* When expanding the fake auto... pack expansion from add_capture, we
12673 need to mark that the expansion is no longer a pack. */
12675 }
12677 /* If the Ith argument pack element is a pack expansion, then
12678 the Ith element resulting from the substituting is going to
12679 be a pack expansion as well. */
12684 }
12686 /* When the unexpanded parameter pack in a fold expression expands to an empty
12687 sequence, the value of the expression is as follows; the program is
12688 ill-formed if the operator is not listed in this table.
12690 && true
12691 || false
12692 , void() */
12694 tree
12696 {
12700 {
12709 }
12715 }
12717 /* Given a fold-expression T and a current LEFT and RIGHT operand,
12718 form an expression that combines the two terms using the
12719 operator of T. */
12721 static tree
12723 {
12728 // Handle compound assignment operators.
12735 {
12744 complain);
12745 }
12746 }
12748 /* Substitute ARGS into the pack of a fold expression T. */
12752 {
12754 }
12756 /* Substitute ARGS into the pack of a fold expression T. */
12760 {
12762 }
12764 /* Expand a PACK of arguments into a grouped as left fold.
12765 Given a pack containing elements A0, A1, ..., An and an
12766 operator @, this builds the expression:
12768 ((A0 @ A1) @ A2) ... @ An
12770 Note that PACK must not be empty.
12772 The operator is defined by the original fold expression T. */
12774 static tree
12776 {
12779 {
12782 }
12784 }
12786 /* Substitute into a unary left fold expression. */
12788 static tree
12790 tree in_decl)
12791 {
12796 {
12800 }
12803 else
12805 }
12807 /* Substitute into a binary left fold expression.
12809 Do ths by building a single (non-empty) vector of argumnts and
12810 building the expression from those elements. */
12812 static tree
12814 tree in_decl)
12815 {
12824 {
12829 }
12837 }
12839 /* Expand a PACK of arguments into a grouped as right fold.
12840 Given a pack containing elementns A0, A1, ..., and an
12841 operator @, this builds the expression:
12843 A0@ ... (An-2 @ (An-1 @ An))
12845 Note that PACK must not be empty.
12847 The operator is defined by the original fold expression T. */
12849 tree
12851 {
12852 // Build the expression.
12856 {
12859 }
12861 }
12863 /* Substitute into a unary right fold expression. */
12865 static tree
12867 tree in_decl)
12868 {
12873 {
12877 }
12880 else
12882 }
12884 /* Substitute into a binary right fold expression.
12886 Do ths by building a single (non-empty) vector of arguments and
12887 building the expression from those elements. */
12889 static tree
12891 tree in_decl)
12892 {
12901 {
12906 }
12915 }
12917 /* Walk through the pattern of a pack expansion, adding everything in
12918 local_specializations to a list. */
12920 class el_data
12921 {
12923 /* Set of variables declared within the pattern. */
12925 /* Set of AST nodes that have been visited by the traversal. */
12927 /* List of local_specializations used within the pattern. */
12928 tree extra;
12929 tsubst_flags_t complain;
12933 };
12934 static tree
12936 {
12942 /* Remember local typedefs (85214). */
12946 {
12952 {
12955 decl2
12961 {
12964 }
12965 }
12966 }
12968 {
12969 /* Since we defer implicit capture, look in the parms and body. */
12975 }
12977 {
12979 /* Don't mess with variables declared within the pattern. */
12982 {
12983 /* Maybe pull out the PARM_DECL for a partial instantiation. */
12986 {
12992 }
12994 {
12995 /* Handle lambda capture here, since we aren't doing any
12996 substitution now, and so tsubst_copy won't call
12997 process_outer_var_ref. */
13001 {
13007 {
13008 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
13009 proxies. */
13011 {
13016 }
13018 }
13019 }
13020 }
13021 }
13025 }
13027 }
13028 static tree
13030 {
13034 }
13036 /* Extract any uses of local_specializations from PATTERN and add them to ARGS
13037 for use in PACK_EXPANSION_EXTRA_ARGS. */
13039 tree
13041 {
13042 /* Make a copy of the extra arguments so that they won't get changed
13043 out from under us. */
13049 }
13051 /* Apply any local specializations from PACK_EXPANSION_EXTRA_ARGS and add the
13052 normal template args to ARGS. */
13054 tree
13056 {
13058 {
13060 {
13061 /* The partial instantiation involved local declarations collected in
13062 extract_local_specs; map from the general template to our local
13063 context. */
13069 /* else inst is already a full instantiation of the pack. */
13071 }
13074 }
13076 {
13077 /* This can happen after dependent substitution into a
13078 requires-expr or a lambda that uses constexpr if. */
13081 }
13082 else
13085 }
13087 /* Substitute ARGS into T, which is an pack expansion
13088 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
13089 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
13090 (if only a partial substitution could be performed) or
13091 ERROR_MARK_NODE if there was an error. */
13092 tree
13094 tree in_decl)
13095 {
13096 tree pattern;
13100 tree result;
13107 /* Add in any args remembered from an earlier partial instantiation. */
13112 /* Determine the argument packs that will instantiate the parameter
13113 packs used in the expansion expression. While we're at it,
13114 compute the number of arguments to be expanded and make sure it
13115 is consistent. */
13118 {
13125 {
13131 complain);
13132 else
13136 }
13138 {
13140 {
13143 parm_pack);
13145 }
13148 }
13150 {
13151 /* We know we have correct local_specializations if this
13152 expansion is at function scope, or if we're dealing with a
13153 local parameter in a requires expression; for the latter,
13154 tsubst_requires_expr set it up appropriately. */
13157 else
13158 /* We can't rely on local_specializations for a parameter
13159 name used later in a function declaration (such as in a
13160 late-specified return type). Even if it exists, it might
13161 have the wrong value for a recursive call. */
13165 {
13166 /* This parameter pack was used in an unevaluated context. Just
13167 make a dummy decl, since it's only used for its type. */
13172 /* Partial instantiation of the parm_pack, we can't build
13173 up an argument pack yet. */
13175 else
13177 }
13179 /* This argument pack isn't fully instantiated yet. */
13181 }
13183 {
13187 }
13188 else
13189 {
13198 }
13205 /* This can only happen if we forget to expand an argument
13206 pack somewhere else. Just return an error, silently. */
13207 {
13211 }
13214 {
13218 /* Don't bother trying to do a partial substitution with
13219 incomplete packs; we'll try again after deduction. */
13226 {
13231 pattern);
13232 else
13234 pattern);
13236 }
13238 /* Keep track of the parameter packs and their corresponding
13239 argument packs. */
13242 }
13243 else
13244 {
13245 /* We can't substitute for this parameter pack. We use a flag as
13246 well as the missing_level counter because function parameter
13247 packs don't have a level. */
13250 }
13251 }
13253 /* If the expansion is just T..., return the matching argument pack, unless
13254 we need to call convert_from_reference on all the elements. This is an
13255 important optimization; see c++/68422. */
13258 {
13261 /* If the argument pack is a single pack expansion, pull it out. */
13266 /* Types need no adjustment, nor does sizeof..., and if we still have
13267 some pack expansion args we won't do anything yet. */
13272 /* Also optimize expression pack expansions if we can tell that the
13273 elements won't have reference type. */
13279 /* Otherwise use the normal path so we get convert_from_reference. */
13280 }
13282 /* We cannot expand this expansion expression, because we don't have
13283 all of the argument packs we need. */
13285 {
13286 /* We got some full packs, but we can't substitute them in until we
13287 have values for all the packs. So remember these until then. */
13293 }
13295 /* If NEED_LOCAL_SPECIALIZATIONS then we're in a late-specified return
13296 type, so create our own local specializations map; the current map is
13297 either NULL or (in the case of recursive unification) might have
13298 bindings that we don't want to use or alter. */
13303 {
13304 /* There were no real arguments, we're just replacing a parameter
13305 pack with another version of itself. Substitute into the
13306 pattern and return a PACK_EXPANSION_*. The caller will need to
13307 deal with that. */
13311 else
13317 {
13318 /* This is a fake auto... pack expansion created in add_capture with
13319 _PACKS that don't appear in the pattern. Copy one over. */
13326 }
13328 }
13332 /* For each argument in each argument pack, substitute into the
13333 pattern. */
13337 {
13339 i,
13341 in_decl);
13344 {
13347 }
13348 }
13350 /* Update ARGS to restore the substitution from parameter packs to
13351 their argument packs. */
13353 {
13360 else
13361 {
13369 /* Update the corresponding argument. */
13373 else
13375 }
13376 }
13378 /* If the dependent pack arguments were such that we end up with only a
13379 single pack expansion again, there's no need to keep it in a TREE_VEC. */
13385 }
13387 /* Make an argument pack out of the TREE_VEC VEC. */
13389 static tree
13391 {
13392 tree pack;
13396 else
13397 {
13400 }
13403 }
13405 /* Return an exact copy of template args T that can be modified
13406 independently. */
13408 static tree
13410 {
13418 {
13423 }
13429 }
13431 /* Substitute ARGS into the *_ARGUMENT_PACK orig_arg. */
13433 tree
13435 tree in_decl)
13436 {
13437 /* Substitute into each of the arguments. */
13442 {
13444 {
13447 }
13448 else
13449 {
13452 }
13455 }
13458 }
13460 /* Substitute ARGS into the vector or list of template arguments T. */
13462 tree
13464 {
13476 {
13478 tree new_arg;
13485 {
13486 /* Substitute into an expansion expression. */
13490 /* Add to the expanded length adjustment the number of
13491 expanded arguments. We subtract one from this
13492 measurement, because the argument pack expression
13493 itself is already counted as 1 in
13494 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
13495 the argument pack is empty. */
13497 }
13500 else
13509 }
13514 /* Make space for the expanded arguments coming from template
13515 argument packs. */
13517 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
13518 arguments for a member template.
13519 In that case each TREE_VEC in ORIG_T represents a level of template
13520 arguments, and ORIG_T won't carry any non defaulted argument count.
13521 It will rather be the nested TREE_VECs that will carry one.
13522 In other words, ORIG_T carries a non defaulted argument count only
13523 if it doesn't contain any nested TREE_VEC. */
13525 {
13529 }
13531 {
13536 {
13539 /* Now expand the template argument pack "in place". */
13542 }
13543 else
13544 {
13546 out++;
13547 }
13548 }
13551 }
13553 /* Substitute ARGS into one level PARMS of template parameters. */
13555 static tree
13557 {
13564 {
13572 }
13575 }
13577 /* Return the result of substituting ARGS into the template parameters
13578 given by PARMS. If there are m levels of ARGS and m + n levels of
13579 PARMS, then the result will contain n levels of PARMS. For
13580 example, if PARMS is `template <class T> template <class U>
13581 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
13582 result will be `template <int*, double, class V>'. */
13584 static tree
13586 {
13590 /* When substituting into a template, we must set
13591 PROCESSING_TEMPLATE_DECL as the template parameters may be
13592 dependent if they are based on one-another, and the dependency
13593 predicates are short-circuit outside of templates. */
13600 {
13609 }
13614 }
13616 /* Return the result of substituting ARGS into one template parameter
13617 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
13618 parameter and which TREE_PURPOSE is the default argument of the
13619 template parameter. */
13621 static tree
13623 {
13648 }
13650 /* Substitute the ARGS into the indicated aggregate (or enumeration)
13651 type T. If T is not an aggregate or enumeration type, it is
13652 handled as if by tsubst. IN_DECL is as for tsubst. If
13653 ENTERING_SCOPE is nonzero, T is the context for a template which
13654 we are presently tsubst'ing. Return the substituted value. */
13656 static tree
13658 tree args,
13659 tsubst_flags_t complain,
13660 tree in_decl,
13662 {
13666 /* If T is an alias template specialization, we want to substitute that
13667 rather than strip it, especially if it's dependent_alias_template_spec_p.
13668 It should be OK not to handle entering_scope in this case, since
13669 DECL_CONTEXT will never be an alias template specialization. We only get
13670 here with an alias when tsubst calls us for TYPENAME_TYPE. */
13675 {
13680 /* Fall through. */
13684 {
13685 tree argvec;
13686 tree context;
13687 tree r;
13689 /* In "sizeof(X<I>)" we need to evaluate "I". */
13690 cp_evaluated ev;
13692 /* First, determine the context for the type we are looking
13693 up. */
13696 {
13699 /* If context is a nested class inside a class template,
13700 it may still need to be instantiated (c++/33959). */
13702 }
13704 /* Then, figure out what arguments are appropriate for the
13705 type we are trying to find. For example, given:
13707 template <class T> struct S;
13708 template <class T, class U> void f(T, U) { S<U> su; }
13710 and supposing that we are instantiating f<int, double>,
13711 then our ARGS will be {int, double}, but, when looking up
13712 S we only want {double}. */
13717 else
13718 {
13722 }
13725 }
13726 else
13727 /* This is not a template type, so there's nothing to do. */
13732 }
13733 }
13735 /* Map from a FUNCTION_DECL to a vec of default argument instantiations,
13736 indexed in reverse order of the parameters. */
13740 /* Return a reference to the vec* of defarg insts for FN. */
13744 {
13748 tree_vec_map **slot
13751 {
13754 }
13756 }
13758 /* Substitute into the default argument ARG (a default argument for
13759 FN), which has the indicated TYPE. */
13761 tree
13763 tsubst_flags_t complain)
13764 {
13767 /* This can happen in invalid code. */
13771 /* Shortcut {}. */
13786 /* Remember the location of the pointer to the vec rather than the location
13787 of the particular element, in case the vec grows in tsubst_expr. */
13789 /* Index in reverse order to avoid allocating space for initial parameters
13790 that don't have default arguments. */
13797 /* This default argument came from a template. Instantiate the
13798 default argument here, not in tsubst. In the case of
13799 something like:
13801 template <class T>
13802 struct S {
13803 static T t();
13804 void f(T = t());
13805 };
13807 we must be careful to do name lookup in the scope of S<T>,
13808 rather than in the current class. */
13814 /* The default argument expression may cause implicitly defined
13815 member functions to be synthesized, which will result in garbage
13816 collection. We must treat this situation as if we were within
13817 the body of function so as to avoid collecting live data on the
13818 stack. */
13827 /* Make sure the default argument is reasonable. */
13843 }
13845 /* Substitute into all the default arguments for FN. */
13847 static void
13849 {
13850 tree arg;
13851 tree tmpl_args;
13855 /* If this function is not yet instantiated, we certainly don't need
13856 its default arguments. */
13859 /* Don't do this again for clones. */
13865 arg;
13871 complain);
13872 }
13874 /* Hash table mapping a FUNCTION_DECL to its dependent explicit-specifier. */
13877 /* Store a pair to EXPLICIT_SPECIFIER_MAP. */
13879 void
13881 {
13886 }
13888 /* Lookup an element in EXPLICIT_SPECIFIER_MAP. */
13890 tree
13892 {
13894 }
13896 /* Given T, a FUNCTION_TYPE or METHOD_TYPE, construct and return a corresponding
13897 FUNCTION_TYPE or METHOD_TYPE whose return type is RETURN_TYPE, argument types
13898 are ARG_TYPES, and exception specification is RAISES, and otherwise is
13899 identical to T. */
13901 static tree
13904 {
13907 tree new_type;
13909 {
13912 }
13913 else
13914 {
13916 /* Don't pick up extra function qualifiers from the basetype. */
13919 {
13920 /* [temp.deduct]
13922 Type deduction may fail for any of the following
13923 reasons:
13925 -- Attempting to create "pointer to member of T" when T
13926 is not a class type. */
13929 r);
13931 }
13935 }
13941 }
13943 /* Check if the function type of DECL, a FUNCTION_DECL, agrees with the type of
13944 each of its formal parameters. If there is a disagreement then rebuild
13945 DECL's function type according to its formal parameter types, as part of a
13946 resolution for Core issues 1001/1322. */
13948 static void
13950 {
13953 {
13956 {
13960 {
13963 }
13967 }
13968 }
13979 {
13984 }
13986 {
13996 }
14004 }
14006 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
14008 static tree
14010 tree lambda_fntype)
14011 {
14016 /* Nobody should be tsubst'ing into non-template functions. */
14021 {
14024 }
14026 {
14027 /* If T is not dependent, just return it. */
14032 /* Calculate the most general template of which R is a
14033 specialization. */
14036 /* We're substituting a lambda function under tsubst_lambda_expr but not
14037 directly from it; find the matching function we're already inside.
14038 But don't do this if T is a generic lambda with a single level of
14039 template parms, as in that case we're doing a normal instantiation. */
14045 /* Calculate the complete set of arguments used to
14046 specialize R. */
14048 (DECL_TEMPLATE_RESULT
14054 /* Check to see if we already have this specialization. */
14056 {
14059 /* The spec for these args might be a partial instantiation of the
14060 template, but here what we want is the FUNCTION_DECL. */
14062 }
14063 }
14064 else
14065 {
14066 /* This special case arises when we have something like this:
14068 template <class T> struct S {
14069 friend void f<int>(int, double);
14070 };
14072 Here, the DECL_TI_TEMPLATE for the friend declaration
14073 will be an IDENTIFIER_NODE. We are being called from
14074 tsubst_friend_function, and we want only to create a
14075 new decl (R) with appropriate types so that we can call
14076 determine_specialization. */
14079 }
14096 /* If we hit excessive deduction depth, the type is bogus even if
14097 it isn't error_mark_node, so don't build a decl. */
14101 /* We do NOT check for matching decls pushed separately at this
14102 point, as they may not represent instantiations of this
14103 template, and in any case are considered separate under the
14104 discrete model. */
14108 /* Clear out the mangled name and RTL for the instantiation. */
14111 /* Leave DECL_INITIAL set on deleted instantiations. */
14117 /* Handle explicit(dependent-expr). */
14119 {
14127 else
14128 {
14131 }
14132 }
14134 /* OpenMP UDRs have the only argument a reference to the declared
14135 type. We want to diagnose if the declared type is a reference,
14136 which is invalid, but as references to references are usually
14137 quietly merged, diagnose it here. */
14139 {
14140 tree argtype
14145 "reference type %qT in "
14149 argtype);
14150 }
14153 /* Type-conversion operator. Reconstruct the name, in
14154 case it's the name of one of the template's parameters. */
14164 {
14169 }
14178 /* If this is an instantiation of a function with internal
14179 linkage, we already know what object file linkage will be
14180 assigned to the instantiation. */
14189 /* We'll re-clone as appropriate in instantiate_template. */
14192 /* If we aren't complaining now, return on error before we register
14193 the specialization so that we'll complain eventually. */
14199 /* Associate the constraints directly with the instantiation. We
14200 don't substitute through the constraints; that's only done when
14201 they are checked. */
14214 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
14215 this in the special friend case mentioned above where
14216 GEN_TMPL is NULL. */
14218 {
14223 tree new_r
14226 /* We instantiated this while substituting into
14227 the type earlier (template/friend54.C). */
14230 /* We're not supposed to instantiate default arguments
14231 until they are called, for a template. But, for a
14232 declaration like:
14234 template <class T> void f ()
14235 { extern void g(int i = T()); }
14237 we should do the substitution when the template is
14238 instantiated. We handle the member function case in
14239 instantiate_class_template since the default arguments
14240 might refer to other members of the class. */
14245 }
14247 {
14250 }
14251 else
14254 /* Copy the list of befriending classes. */
14258 {
14262 }
14265 {
14269 /* If this is an instantiation of a member template, clone it.
14270 If it isn't, that'll be handled by
14271 clone_constructors_and_destructors. */
14274 }
14280 /* Possibly limit visibility based on template args. */
14283 {
14287 }
14299 }
14301 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
14303 static tree
14305 tree lambda_fntype)
14306 {
14307 /* We can get here when processing a member function template,
14308 member class template, or template template parameter. */
14311 tree spec;
14312 tree tmpl_args;
14313 tree full_args;
14314 tree r;
14318 {
14319 /* Template template parameter is treated here. */
14323 /* If we get a real template back, return it. This can happen in
14324 the context of most_specialized_partial_spec. */
14327 else
14328 /* The new TEMPLATE_DECL was built in
14329 reduce_template_parm_level. */
14332 }
14335 {
14336 /* We might already have an instance of this template.
14337 The ARGS are for the surrounding class type, so the
14338 full args contain the tsubst'd args for the context,
14339 plus the innermost args from the template decl. */
14343 /* Because this is a template, the arguments will still be
14344 dependent, even after substitution. If
14345 PROCESSING_TEMPLATE_DECL is not set, the dependency
14346 predicates will short-circuit. */
14354 /* If this is a default template template argument,
14355 tsubst might not have changed anything. */
14362 {
14364 /* Type partial instantiations are stored as the type by
14365 lookup_template_class_1, not here as the template. */
14368 }
14369 }
14371 /* Make a new template decl. It will be similar to the
14372 original, but will record the current template arguments.
14373 We also create a new function declaration, which is just
14374 like the old one, but points to this new template, rather
14375 than the old one. */
14380 // Build new template info linking to the original template decl.
14382 {
14385 }
14386 else
14389 /* The template parameters for this new template are all the
14390 template parameters for the old template, except the
14391 outermost level of parameters. */
14394 = current_template_parms
14396 complain);
14403 else
14404 {
14406 {
14409 }
14413 else
14415 }
14421 {
14422 /* For a partial specialization, we need to keep pointing to
14423 the primary template. */
14429 }
14431 {
14434 }
14435 else
14436 {
14439 }
14446 {
14447 /* Propagate module information from the decl. */
14450 /* If this is a constrained template, the above tsubst of
14451 inner can find the unconstrained template, which may have
14452 come from an import. This is ok, because we don't
14453 register this instantiation (see below). */
14455 || (TEMPLATE_PARMS_CONSTRAINTS
14457 }
14466 /* Record this non-type partial instantiation. */
14472 }
14474 /* True if FN is the op() for a lambda in an uninstantiated template. */
14476 bool
14478 {
14483 }
14485 /* True if FN is the substitution (via tsubst_lambda_expr) of a function for
14486 which the above is true. */
14488 bool
14490 {
14496 }
14498 /* Return the LAMBDA_EXPR from which T was ultimately regenerated.
14499 If T is not a regenerated LAMBDA_EXPR, return T. */
14501 tree
14503 {
14507 }
14509 /* Return the set of template arguments used to regenerate the lambda T
14510 from its most general lambda. */
14512 tree
14514 {
14520 else
14522 }
14524 /* We're instantiating a variable from template function TCTX. Return the
14525 corresponding current enclosing scope. We can match them up using
14526 DECL_SOURCE_LOCATION because lambdas only ever have one source location, and
14527 the DECL_SOURCE_LOCATION for a function instantiation is updated to match
14528 the template definition in regenerate_decl_from_template. */
14530 static tree
14532 {
14535 /* We shouldn't ever need to do this for other artificial functions. */
14542 }
14544 /* Substitute the ARGS into the T, which is a _DECL. Return the
14545 result of the substitution. Issue error and warning messages under
14546 control of COMPLAIN. */
14548 static tree
14550 {
14551 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
14552 location_t saved_loc;
14557 /* Set the filename and linenumber to improve error-reporting. */
14562 {
14572 {
14580 {
14581 /* If there is a local specialization that isn't a
14582 parameter pack, it means that we're doing a "simple"
14583 substitution from inside tsubst_pack_expansion. Just
14584 return the local specialization (which will be a single
14585 parm). */
14592 /* Expand the TYPE_PACK_EXPANSION that provides the types for
14593 the parameters in this function parameter pack. */
14597 {
14600 /* Zero-length parameter packs are boring. Just substitute
14601 into the chain. */
14605 }
14606 else
14607 {
14608 /* All we did was update the type. Make a note of that. */
14611 }
14612 }
14614 /* Loop through all of the parameters we'll build. When T is
14615 a function parameter pack, LEN is the number of expanded
14616 types in EXPANDED_TYPES; otherwise, LEN is 1. */
14619 {
14626 /* We're on the Ith parameter of the function parameter
14627 pack. */
14628 {
14629 /* Get the Ith type. */
14632 /* Rename the parameter to include the index. */
14635 }
14637 /* We're dealing with a normal parameter. */
14645 {
14648 else
14651 }
14662 /* Keep track of the first new parameter we
14663 generate. That's what will be returned to the
14664 caller. */
14668 /* Build a proper chain of parameters when substituting
14669 into a function parameter pack. */
14672 }
14674 /* If cp_unevaluated_operand is set, we're just looking for a
14675 single dummy parameter, so don't keep going. */
14680 /* FIRST_R contains the start of the chain we've built. */
14682 }
14686 {
14693 {
14694 /* This field is a lambda capture pack. Return a TREE_VEC of
14695 the expanded fields to instantiate_class_template_1. */
14699 {
14702 }
14703 else
14704 {
14705 /* All we did was update the type. Make a note of that. */
14708 }
14709 }
14712 {
14715 {
14719 }
14729 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
14730 number of bits. */
14736 {
14737 /* Set up DECL_TEMPLATE_INFO so that we can get at the
14738 NSDMI in perform_member_init. Still set DECL_INITIAL
14739 so that we know there is one. */
14744 }
14745 /* We don't have to set DECL_CONTEXT here; it is set by
14746 finish_member_declaration. */
14755 }
14759 }
14763 /* We reach here only for member using decls. We also need to check
14764 uses_template_parms because DECL_DEPENDENT_P is not set for a
14765 using-declaration that designates a member of the current
14766 instantiation (c++/53549). */
14769 {
14773 {
14778 {
14782 {
14785 }
14786 else
14787 {
14790 }
14792 }
14793 }
14794 else
14795 {
14801 else
14802 {
14805 }
14806 }
14807 }
14808 else
14809 {
14812 }
14817 {
14828 {
14829 /* If this is the canonical decl, we don't have to
14830 mess with instantiations, and often we can't (for
14831 typename, template type parms and such). Note that
14832 TYPE_NAME is not correct for the above test if
14833 we've copied the type for a typedef. */
14839 }
14841 /* Check to see if we already have the specialization we
14842 need. */
14848 {
14851 {
14853 complain,
14855 /* If CTX is unchanged, then T is in fact the
14856 specialization we want. That situation occurs when
14857 referencing a static data member within in its own
14858 class. We can use pointer equality, rather than
14859 same_type_p, because DECL_CONTEXT is always
14860 canonical... */
14862 /* ... unless T is a member template; in which
14863 case our caller can be willing to create a
14864 specialization of that template represented
14865 by T. */
14869 }
14872 {
14877 argvec = (coerce_innermost_template_parms
14885 }
14886 }
14887 else
14888 {
14890 /* Subsequent calls to pushdecl will fill this in. */
14892 /* A local variable. */
14894 /* Unless this is a reference to a static variable from an
14895 enclosing function, in which case we need to fill it in now. */
14897 {
14901 }
14903 }
14904 /* If we already have the specialization we need, there is
14905 nothing more to do. */
14907 {
14910 }
14912 /* Create a new node for the specialization we need. */
14914 {
14917 else
14927 /* Substituting the type might have recursively instantiated this
14928 same alias (c++/86171). */
14931 {
14934 }
14935 }
14938 {
14944 {
14945 /* It may seem that this case cannot occur, since:
14947 typedef void f();
14948 void g() { f x; }
14950 declares a function, not a variable. However:
14952 typedef void f();
14953 template <typename T> void g() { T t; }
14954 template void g<f>();
14956 is an attempt to declare a variable with function
14957 type. */
14959 /* R is not yet sufficiently initialized, so we
14960 just use its name. */
14963 }
14965 /* Wait until cp_finish_decl to set this again, to handle
14966 circular dependency (template/instantiate6.C). */
14971 {
14973 /* If the DECL_VALUE_EXPR is converted to the declared type,
14974 preserve the identity so that gimplify_type_sizes works. */
14981 {
14984 }
14993 else
14997 }
15001 }
15007 /* Clear out the mangled name and RTL for the instantiation. */
15013 /* The initializer must not be expanded until it is required;
15014 see [temp.inst]. */
15018 {
15024 /* Possibly limit visibility based on template args. */
15027 {
15031 }
15033 }
15036 {
15037 /* A static data member declaration is always marked
15038 external when it is declared in-class, even if an
15039 initializer is present. We mimic the non-template
15040 processing here. */
15049 }
15050 else
15051 {
15056 }
15065 /* Preserve a typedef that names a type. */
15067 {
15071 /* common_handle_aligned_attribute doesn't apply the alignment
15072 to DECL_ORIGINAL_TYPE. */
15076 }
15079 }
15084 }
15085 #undef RETURN
15087 out:
15088 /* Restore the file and line information. */
15092 }
15094 /* Substitute into the complete parameter type list PARMS. */
15096 tree
15098 tree args,
15099 tsubst_flags_t complain,
15100 tree in_decl)
15101 {
15103 }
15105 /* Substitute into the ARG_TYPES of a function type.
15106 If END is a TREE_CHAIN, leave it and any following types
15107 un-substituted. */
15109 static tree
15111 tree args,
15112 tree end,
15113 tsubst_flags_t complain,
15114 tree in_decl)
15115 {
15124 {
15125 /* For a pack expansion, perform substitution on the
15126 entire expression. Later on, we'll handle the arguments
15127 one-by-one. */
15132 /* So that we'll spin through the parameters, one by one. */
15134 else
15135 {
15136 /* We only partially substituted into the parameter
15137 pack. Our type is TYPE_PACK_EXPANSION. */
15140 }
15141 }
15142 else
15145 /* Check if a substituted type is erroneous before substituting into
15146 the rest of the chain. */
15148 {
15155 {
15157 {
15161 }
15163 }
15164 }
15166 /* We do not substitute into default arguments here. The standard
15167 mandates that they be instantiated only when needed, which is
15168 done in build_over_call. */
15171 /* Except that we do substitute default arguments under tsubst_lambda_expr,
15172 since the new op() won't have any associated template arguments for us
15173 to refer to later. */
15186 {
15190 /* Do array-to-pointer, function-to-pointer conversion, and ignore
15191 top-level qualifiers as required. */
15195 {
15196 /* We've instantiated a template before its default arguments
15197 have been parsed. This can happen for a nested template
15198 class, and is not an error unless we require the default
15199 argument in a call of this function. */
15200 remaining_arg_types
15203 remaining_arg_types);
15204 }
15205 else
15206 remaining_arg_types
15208 }
15211 }
15213 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
15214 *not* handle the exception-specification for FNTYPE, because the
15215 initial substitution of explicitly provided template parameters
15216 during argument deduction forbids substitution into the
15217 exception-specification:
15219 [temp.deduct]
15221 All references in the function type of the function template to the
15222 corresponding template parameters are replaced by the specified tem-
15223 plate argument values. If a substitution in a template parameter or
15224 in the function type of the function template results in an invalid
15225 type, type deduction fails. [Note: The equivalent substitution in
15226 exception specifications is done only when the function is instanti-
15227 ated, at which point a program is ill-formed if the substitution
15228 results in an invalid type.] */
15230 static tree
15232 tree args,
15233 tsubst_flags_t complain,
15234 tree in_decl)
15235 {
15236 tree return_type;
15239 /* The TYPE_CONTEXT is not used for function/method types. */
15242 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
15243 failure. */
15247 {
15248 /* Substitute the argument types. */
15260 {
15261 /* DR 1207: 'this' is in scope in the trailing return type. */
15263 }
15265 /* Substitute the return type. */
15269 {
15272 }
15273 }
15274 else
15275 /* Substitute the return type. */
15280 /* DR 486 clarifies that creation of a function type with an
15281 invalid return type is a deduction failure. */
15284 {
15286 {
15289 else
15291 }
15293 }
15296 {
15297 /* Substitute the argument types. */
15302 }
15304 /* Construct a new type node and return it. */
15307 }
15309 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
15310 ARGS into that specification, and return the substituted
15311 specification. If there is no specification, return NULL_TREE. */
15313 static tree
15315 tree args,
15316 tsubst_flags_t complain,
15317 tree in_decl,
15319 {
15320 tree specs;
15321 tree new_specs;
15326 {
15327 /* A noexcept-specifier. */
15332 {
15333 /* Defer instantiation of noexcept-specifiers to avoid
15334 excessive instantiations (c++/49107). */
15337 {
15338 /* We already partially instantiated this member template,
15339 so combine the new args with the old. */
15344 }
15345 else
15346 {
15349 }
15350 }
15351 else
15352 {
15354 {
15356 args);
15358 }
15359 new_specs = tsubst_copy_and_build
15362 }
15364 /* We've instantiated a template before a noexcept-specifier
15365 contained therein has been parsed. This can happen for
15366 a nested template class:
15368 struct S {
15369 template<typename> struct B { B() noexcept(...); };
15370 struct A : B<int> { ... use B() ... };
15371 };
15373 where completing B<int> will trigger instantiating the
15374 noexcept, even though we only parse it at the end of S. */
15376 {
15379 }
15380 }
15382 {
15385 else
15387 {
15388 tree spec;
15393 {
15394 /* Expand the pack expansion type. */
15397 in_decl);
15403 else
15404 {
15405 /* We're substituting into a member template, so
15406 we got a TYPE_PACK_EXPANSION back. Add that
15407 expansion and move on. */
15411 expanded_specs,
15412 complain);
15415 }
15416 }
15419 {
15422 else
15427 complain);
15428 }
15431 }
15432 }
15434 }
15436 /* Substitute through a TREE_LIST of types or expressions, handling pack
15437 expansions. */
15439 tree
15441 {
15448 ;
15450 {
15454 }
15457 else
15465 ;
15467 {
15471 }
15474 else
15481 ;
15486 else
15497 /* Determine the number of arguments. */
15499 {
15502 }
15505 else
15509 {
15517 else
15519 }
15522 }
15524 /* Take the tree structure T and replace template parameters used
15525 therein with the argument vector ARGS. IN_DECL is an associated
15526 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
15527 Issue error and warning messages under control of COMPLAIN. Note
15528 that we must be relatively non-tolerant of extensions here, in
15529 order to preserve conformance; if we allow substitutions that
15530 should not be allowed, we may allow argument deductions that should
15531 not succeed, and therefore report ambiguous overload situations
15532 where there are none. In theory, we could allow the substitution,
15533 but indicate that it should have failed, and allow our caller to
15534 make sure that the right thing happens, but we don't try to do this
15535 yet.
15537 This function is used for dealing with types, decls and the like;
15538 for expressions, use tsubst_expr or tsubst_copy. */
15540 tree
15542 {
15571 /* Reuse typedefs. We need to do this to handle dependent attributes,
15572 such as attribute aligned. */
15575 {
15579 {
15580 /* DECL represents an alias template and we want to
15581 instantiate it. */
15585 }
15589 {
15593 }
15598 else
15599 /* The typedef is from a non-template context. */
15603 {
15605 r = cp_build_qualified_type
15609 }
15610 else
15611 {
15612 /* We don't have an instantiation yet, so drop the typedef. */
15617 }
15618 }
15638 {
15665 {
15671 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
15672 needed. */
15678 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
15679 with TREE_SIDE_EFFECTS that indicates this is not an integral
15680 constant expression. */
15683 {
15686 }
15689 }
15693 {
15701 else
15703 }
15704 /* Fall through. */
15708 {
15722 {
15725 /* See through ARGUMENT_PACK_SELECT arguments. */
15728 }
15733 {
15735 /* If ARG is an argument pack, we don't actually want to
15736 perform a substitution here, because substitutions
15737 for argument packs are only done
15738 element-by-element. We can get to this point when
15739 substituting the type of a non-type template
15740 parameter pack, when that type actually contains
15741 template parameter packs from an outer template, e.g.,
15743 template<typename... Types> struct A {
15744 template<Types... Values> struct B { };
15745 }; */
15749 {
15752 /* When building concept checks for the purpose of
15753 deducing placeholders, we can end up with wildcards
15754 where types are expected. Adjust this to the deduced
15755 value. */
15763 return cp_build_qualified_type
15765 }
15767 {
15768 /* We are processing a type constructed from a
15769 template template parameter. */
15780 /* Consider this code:
15782 template <template <class> class Template>
15783 struct Internal {
15784 template <class Arg> using Bind = Template<Arg>;
15785 };
15787 template <template <class> class Template, class Arg>
15788 using Instantiate = Template<Arg>; //#0
15790 template <template <class> class Template,
15791 class Argument>
15792 using Bind =
15793 Instantiate<Internal<Template>::template Bind,
15794 Argument>; //#1
15796 When #1 is parsed, the
15797 BOUND_TEMPLATE_TEMPLATE_PARM representing the
15798 parameter `Template' in #0 matches the
15799 UNBOUND_CLASS_TEMPLATE representing the argument
15800 `Internal<Template>::template Bind'; We then want
15801 to assemble the type `Bind<Argument>' that can't
15802 be fully created right now, because
15803 `Internal<Template>' not being complete, the Bind
15804 template cannot be looked up in that context. So
15805 we need to "store" `Bind<Argument>' for later
15806 when the context of Bind becomes complete. Let's
15807 store that in a TYPENAME_TYPE. */
15811 argvec),
15812 typename_type,
15813 complain);
15815 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
15816 are resolving nested-types in the signature of a
15817 member function templates. Otherwise ARG is a
15818 TEMPLATE_DECL and is the real template to be
15819 instantiated. */
15827 complain);
15828 return cp_build_qualified_type
15830 }
15833 else
15834 /* TEMPLATE_PARM_INDEX. */
15836 }
15839 /* This can happen during the attempted tsubst'ing in
15840 unify. This means that we don't yet have any information
15841 about the template parameter in question. */
15844 /* Early in template argument deduction substitution, we don't
15845 want to reduce the level of 'auto', or it will be confused
15846 with a normal template parm in subsequent deduction.
15847 Similarly, don't reduce the level of template parameters to
15848 avoid mismatches when deducing their types. */
15852 /* If we get here, we must have been looking at a parm for a
15853 more deeply nested template. Make a new version of this
15854 template parameter, but with a lower level. */
15856 {
15861 {
15863 r = cp_build_qualified_type
15867 }
15874 /* Break infinite recursion when substituting the constraints
15882 /* Cache the simple case of lowering a type parameter. */
15884 else
15885 {
15897 /* Propagate constraints on placeholders since they are
15898 only instantiated during satisfaction. */
15902 {
15904 /* We might need to substitute into the types of non-type
15905 template parameters. */
15917 }
15921 else
15923 }
15927 /* OK, now substitute the type of the non-type parameter. We
15928 couldn't do it earlier because it might be an auto parameter,
15929 and we wouldn't need to if we had an argument. */
15938 }
15941 }
15947 /* We should never be tsubsting a binfo. */
15951 /* A vector of template arguments. */
15957 {
15961 /* [temp.deduct]
15963 Type deduction may fail for any of the following
15964 reasons:
15966 -- Attempting to create a pointer to reference type.
15967 -- Attempting to create a reference to a reference type or
15968 a reference to void.
15970 Core issue 106 says that creating a reference to a reference
15971 during instantiation is no longer a cause for failure. We
15972 only enforce this check in strict C++98 mode. */
15976 {
15979 /* We keep track of the last time we issued this error
15980 message to avoid spewing a ton of messages during a
15981 single bad template instantiation. */
15984 {
15989 else
15992 }
15995 }
15999 {
16001 {
16004 type);
16005 else
16007 type);
16008 }
16010 }
16012 {
16016 }
16018 /* In C++0x, during template argument substitution, when there is an
16019 attempt to create a reference to a reference type, reference
16020 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
16022 "If a template-argument for a template-parameter T names a type
16023 that is a reference to a type A, an attempt to create the type
16024 'lvalue reference to cv T' creates the type 'lvalue reference to
16025 A,' while an attempt to create the type type rvalue reference to
16026 cv T' creates the type T"
16027 */
16028 r = cp_build_reference_type
16031 else
16036 /* Will this ever be needed for TYPE_..._TO values? */
16040 }
16042 {
16045 {
16046 /* [temp.deduct]
16048 Type deduction may fail for any of the following
16049 reasons:
16051 -- Attempting to create "pointer to member of T" when T
16052 is not a class type. */
16056 }
16058 {
16062 }
16064 {
16068 }
16071 {
16072 /* The type of the implicit object parameter gets its
16073 cv-qualifiers from the FUNCTION_TYPE. */
16074 tree memptr;
16075 tree method_type
16080 complain);
16081 }
16082 else
16085 complain);
16086 }
16089 {
16090 tree fntype;
16091 tree specs;
16096 /* Substitute the exception specification. */
16104 }
16106 {
16111 /* As an optimization, we avoid regenerating the array type if
16112 it will obviously be the same as T. */
16116 /* These checks should match the ones in create_array_type_for_decl.
16118 [temp.deduct]
16120 The deduction may fail for any of the following reasons:
16122 -- Attempting to create an array with an element type that
16123 is void, a function type, or a reference type, or [DR337]
16124 an abstract class type. */
16130 {
16134 }
16147 {
16150 }
16153 }
16156 {
16159 {
16165 {
16170 }
16172 }
16173 else
16185 {
16189 }
16191 {
16192 /* Normally, make_typename_type does not require that the CTX
16193 have complete type in order to allow things like:
16195 template <class T> struct S { typename S<T>::X Y; };
16197 But, such constructs have already been resolved by this
16198 point, so here CTX really should have complete type, unless
16199 it's a partial instantiation. */
16202 }
16211 {
16214 }
16217 {
16219 {
16223 else
16225 }
16227 {
16231 else
16233 }
16234 }
16236 return cp_build_qualified_type
16238 }
16241 {
16253 }
16256 {
16257 tree type;
16273 complain);
16274 }
16277 {
16278 tree type;
16297 else
16298 {
16302 /* In a template ~id could be either a complement expression
16303 or an unqualified-id naming a destructor; if instantiating
16304 it produces an expression, it's not an id-expression or
16305 member access. */
16308 }
16313 }
16316 {
16320 }
16339 /* We should use one of the expression tsubsts for these codes. */
16345 }
16346 }
16348 /* OLDFNS is a lookup set of member functions from some class template, and
16349 NEWFNS is a lookup set of member functions from NEWTYPE, a specialization
16350 of that class template. Return the subset of NEWFNS which are
16351 specializations of a function from OLDFNS. */
16353 static tree
16355 {
16356 /* Record all member functions from the old lookup set OLDFNS into
16357 VISIBLE_SET. */
16361 {
16363 {
16364 /* Imprecisely handle dependent using-decl by keeping all members
16365 in the new lookup set that are defined in a base class, i.e.
16366 members that could plausibly have been introduced by this
16367 dependent using-decl.
16368 FIXME: Track which members are introduced by a dependent
16369 using-decl precisely, perhaps by performing another lookup
16370 from the substituted USING_DECL_SCOPE. */
16373 }
16374 else
16376 }
16378 /* Returns true iff (a less specialized version of) FN appeared in
16379 the old lookup set OLDFNS. */
16382 /* FN is a member function from a base class, introduced via a
16383 using-decl; if it might have been introduced by a dependent
16384 using-decl then just conservatively keep it, otherwise look
16385 in the old lookup set for FN exactly. */
16388 /* FN is a member function template from the current class;
16389 look in the old lookup set for the TEMPLATE_DECL from which
16390 it was specialized. */
16392 else
16393 /* FN is a non-template member function from the current class;
16394 look in the old lookup set for the FUNCTION_DECL from which
16395 it was specialized. */
16398 };
16403 {
16406 }
16410 /* Filter out from NEWFNS the member functions that weren't
16411 previously visible according to OLDFNS. */
16416 {
16418 filtered_size++;
16419 }
16425 }
16427 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
16428 expression on the left-hand side of the "." or "->" operator. We
16429 only do the lookup if we had a dependent BASELINK. Otherwise we
16430 adjust it onto the instantiated heirarchy. */
16432 static tree
16435 {
16447 {
16454 }
16462 {
16467 /* See maybe_dependent_member_ref. */
16469 {
16472 template_args);
16475 }
16478 /* Treat as-if non-dependent below. */
16483 complain);
16485 {
16486 /* Filter out from the new lookup set those functions which didn't
16487 appear in the original lookup set (in a less specialized form).
16488 This is needed to preserve the consistency of member lookup
16489 performed in an incomplete-class context, within which
16490 later-declared members ought to remain invisible. */
16493 binfo_type);
16495 }
16498 {
16504 }
16507 }
16508 else
16509 {
16510 /* We're going to overwrite pieces below, make a duplicate. */
16514 {
16515 /* The decl we found was from non-dependent scope, but we still need
16516 to update the binfos for the instantiated qualifying_scope. */
16520 }
16521 }
16523 /* If lookup found a single function, mark it as used at this point.
16524 (If lookup found multiple functions the one selected later by
16525 overload resolution will be marked as used at that point.) */
16527 {
16533 /* We might have instantiated an auto function. */
16535 }
16538 {
16539 /* Add back the template arguments, if present. */
16544 /* Update the conversion operator type. */
16546 }
16552 {
16554 qualifying_scope,
16555 object_type);
16557 /* We need to call adjust_result_of_qualified_name_lookup in case the
16558 destructor names a base class, but we unset BASELINK_QUALIFIED_P
16559 so that we still get virtual function binding. */
16561 }
16564 }
16566 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
16567 true if the qualified-id will be a postfix-expression in-and-of
16568 itself; false if more of the postfix-expression follows the
16569 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
16570 of "&". */
16572 static tree
16576 {
16577 tree expr;
16578 tree scope;
16579 tree name;
16581 tree template_args;
16586 /* Figure out what name to look up. */
16589 {
16598 }
16599 else
16600 {
16603 }
16605 /* Substitute into the qualifying scope. When there are no ARGS, we
16606 are just trying to simplify a non-dependent expression. In that
16607 case the qualifying scope may be dependent, and, in any case,
16608 substituting will not help. */
16611 {
16614 }
16615 else
16619 {
16621 /* We built one in tsubst_baselink. */
16623 else
16624 {
16627 template_args);
16629 QUALIFIED_NAME_IS_TEMPLATE
16631 }
16634 }
16637 {
16639 {
16640 /* A BIT_NOT_EXPR is used to represent a destructor. */
16642 {
16646 }
16647 else
16650 }
16651 else
16655 {
16657 {
16661 }
16663 }
16664 }
16667 {
16671 /* Remember that there was a reference to this entity. */
16674 }
16677 {
16683 }
16686 {
16687 /* We may be repeating a check already done during parsing, but
16688 if it was well-formed and passed then, it will pass again
16689 now, and if it didn't, we wouldn't have got here. The case
16690 we want to catch is when we couldn't tell then, and can now,
16691 namely when templ prior to substitution was an
16692 identifier. */
16698 complain);
16699 else
16701 }
16707 {
16708 expr = (adjust_result_of_qualified_name_lookup
16710 expr = (finish_qualified_id_expr
16714 }
16716 /* Expressions do not generally have reference type. */
16718 /* However, if we're about to form a pointer-to-member, we just
16719 want the referenced member referenced. */
16729 }
16731 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
16732 initializer, DECL is the substituted VAR_DECL. Other arguments are as
16733 for tsubst. */
16735 static tree
16738 {
16747 {
16749 {
16751 {
16756 }
16757 }
16759 {
16760 /* If we had an initializer but it
16761 instantiated to nothing,
16762 value-initialize the object. This will
16763 only occur when the initializer was a
16764 pack expansion where the parameter packs
16765 used in that expansion were of length
16766 zero. */
16772 }
16773 }
16776 }
16778 /* If T is a reference to a dependent member of the current instantiation C and
16779 we are trying to refer to that member in a partial instantiation of C,
16780 return a SCOPE_REF; otherwise, return NULL_TREE.
16782 This can happen when forming a C++17 deduction guide, as in PR96199. */
16784 static tree
16786 tree in_decl)
16787 {
16804 {
16813 complain);
16814 }
16819 {
16825 }
16828 {
16831 /* The TYPE_DECL for a typename has DECL_CONTEXT of the typename
16832 scope, but it doesn't need to be rewritten again. */
16836 }
16840 else
16843 }
16845 /* Like tsubst, but deals with expressions. This function just replaces
16846 template parms; to finish processing the resultant expression, use
16847 tsubst_copy_and_build or tsubst_expr. */
16849 static tree
16851 {
16853 tree r;
16864 {
16869 {
16870 /* We get here for a use of 'this' in an NSDMI. */
16874 /* This can happen for a parameter name used later in a function
16875 declaration (such as in a late-specified return type). Just
16876 make a dummy decl, since it's only used for its type. */
16879 /* Give it the template pattern as its context; its true context
16880 hasn't been instantiated yet and this is good enough for
16881 mangling. */
16883 }
16892 {
16893 tree enum_type;
16894 tree v;
16898 /* There is no need to substitute into namespace-scope
16899 enumerators. */
16902 /* If ARGS is NULL, then T is known to be non-dependent. */
16906 /* Unfortunately, we cannot just call lookup_name here.
16907 Consider:
16909 template <int I> int f() {
16910 enum E { a = I };
16911 struct S { void g() { E e = a; } };
16912 };
16914 When we instantiate f<7>::S::g(), say, lookup_name is not
16915 clever enough to find f<7>::a. */
16916 enum_type
16926 /* We didn't find the name. That should never happen; if
16927 name-lookup found it during preliminary parsing, we
16928 should find it again here during instantiation. */
16930 }
16935 {
16936 tree ctx;
16941 {
16944 {
16948 }
16950 }
16951 }
16960 {
16961 /* Local specialization will usually have been created when
16962 we instantiated the DECL_EXPR_DECL. */
16965 {
16966 /* We're in a generic lambda referencing a local extern
16967 from an outer block-scope of a non-template. */
16970 }
16971 }
16974 {
16977 {
16978 /* First try name lookup to find the instantiation. */
16981 {
16983 {
16984 /* During error-recovery we may find a non-variable,
16985 even an OVERLOAD: just bail out and avoid ICEs and
16986 duplicate diagnostics (c++/62207). */
16989 }
16991 {
16992 /* Make sure the one we found is the one we want. */
16996 }
16997 }
17001 else
17002 {
17003 /* This can happen for a variable used in a
17004 late-specified return type of a local lambda, or for a
17005 local static or constant. Building a new VAR_DECL
17006 should be OK in all those cases. */
17009 /* Avoid infinite recursion (79640). */
17012 {
17013 /* We can't call cp_finish_decl, so handle the
17014 initializer by hand. */
17029 }
17036 }
17037 /* Remember this for subsequent uses. */
17040 }
17043 }
17044 else
17068 {
17069 /* Template template argument like the following example need
17070 special treatment:
17072 template <template <class> class TT> struct C {};
17073 template <class T> struct D {
17074 template <class U> struct E {};
17075 C<E> c; // #1
17076 };
17077 D<int> d; // #2
17079 We are processing the template argument `E' in #1 for
17080 the template instantiation #2. Originally, `E' is a
17081 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
17082 have to substitute this with one having context `D<int>'. */
17086 }
17087 else
17088 /* Ordinary template template argument. */
17093 {
17094 /* Handle location wrappers by substituting the wrapped node
17095 first, *then* reusing the resulting type. Doing the type
17096 first ensures that we handle template parameters and
17097 parameter pack expansions. */
17099 {
17103 }
17107 {
17108 /* Wrapper to make a C++20 template parameter object const. */
17111 {
17112 /* The template argument is not const, presumably because
17113 it is still dependent, and so not the const template parm
17114 object. */
17120 {
17121 /* Don't add a wrapper to these. */
17124 }
17125 else
17126 /* Do add a wrapper otherwise (in particular, if op is
17127 another TEMPLATE_PARM_INDEX). */
17129 }
17131 }
17132 /* force_paren_expr can also create a VIEW_CONVERT_EXPR. */
17134 {
17139 }
17140 /* We shouldn't see any other uses of these in templates. */
17142 }
17150 CASE_CONVERT:
17151 {
17158 }
17161 {
17167 }
17172 {
17181 /* We only want to compute the number of arguments. */
17184 else
17191 {
17193 /* Set TREE_USED for the benefit of -Wunused. */
17197 }
17205 {
17210 else
17218 else
17223 }
17224 else
17226 }
17228 {
17236 }
17237 /* Fall through */
17253 {
17259 /* For addresses of immediate functions ensure we have EXPR_LOCATION
17260 set for possible later diagnostics. */
17267 }
17270 {
17271 tree object;
17272 tree name;
17277 {
17281 }
17284 {
17294 }
17299 in_decl);
17300 else
17303 }
17339 {
17343 }
17346 {
17351 }
17354 {
17358 }
17361 {
17369 }
17375 {
17382 }
17385 {
17392 }
17395 {
17402 }
17405 {
17406 /* Substituted template arguments */
17416 else
17418 }
17421 {
17441 }
17466 /* Fall through. */
17469 {
17472 }
17473 else
17477 /* This is handled by tsubst_copy_and_build. */
17481 {
17485 }
17488 /* We shouldn't have built any of these during initial template
17489 generation. Instead, they should be built during instantiation
17490 in response to the saved STMT_IS_FULL_EXPR_P setting. */
17494 {
17504 }
17522 {
17523 /* Instantiate any typedefs in the type. */
17528 }
17531 {
17535 {
17538 }
17540 }
17543 /* These can sometimes show up in a partial instantiation, but never
17544 involve template parms. */
17560 /* ??? There's no point in copying it for now, but maybe some
17561 day it will contain more information, such as a pointer back
17562 to the containing function, inlined copy or so. */
17571 /* We shouldn't get here, but keep going if !flag_checking. */
17575 }
17576 }
17578 /* Helper function for tsubst_omp_clauses, used for instantiation of
17579 OMP_CLAUSE_DECL of clauses. */
17581 static tree
17584 {
17588 /* Handle OpenMP iterators. */
17592 {
17593 tree ret;
17596 else
17597 {
17601 {
17618 }
17622 }
17626 }
17628 /* Handle an OpenMP array section represented as a TREE_LIST (or
17629 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
17630 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
17631 TREE_LIST. We can handle it exactly the same as an array section
17632 (purpose, value, and a chain), even though the nomenclature
17633 (low_bound, length, etc) is different. */
17635 {
17636 tree low_bound
17651 }
17654 /* Undo convert_from_reference tsubst_expr could have called. */
17660 }
17662 /* Like tsubst_copy, but specifically for OpenMP clauses. */
17664 static tree
17667 {
17673 {
17679 {
17682 {
17688 }
17689 /* FALLTHRU */
17719 /* FALLTHRU */
17753 {
17756 {
17763 }
17764 else
17766 }
17796 {
17799 }
17804 else
17807 in_decl,
17836 }
17839 {
17856 /* tsubst_expr on SCOPE_REF results in returning
17857 finish_non_static_data_member result. Undo that here. */
17861 {
17866 {
17870 CASE_CONVERT:
17879 /* FALLTHRU */
17883 }
17884 }
17890 {
17893 {
17896 }
17897 }
17901 }
17902 }
17906 {
17911 {
17914 }
17915 }
17917 }
17919 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
17921 static tree
17923 tree in_decl)
17924 {
17925 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
17945 {
17948 else
17949 {
17953 }
17954 }
17959 #undef RECUR
17960 }
17962 /* Used to temporarily communicate the list of #pragma omp parallel
17963 clauses to #pragma omp for instantiation if they are combined
17964 together. */
17971 /* Substitute one OMP_FOR iterator. */
17973 static bool
17978 {
17979 #define RECUR(NODE) \
17980 tsubst_expr ((NODE), args, complain, in_decl, \
17981 integral_constant_expression_p)
17993 {
17996 {
18001 {
18011 else
18013 {
18015 {
18021 }
18024 }
18025 }
18026 }
18030 }
18032 {
18033 /* We need to jump through some hoops to handle declarations in the
18034 init-statement, since we might need to handle auto deduction,
18035 but we need to keep control of initialization. */
18039 }
18040 else
18041 {
18043 {
18046 {
18050 {
18054 CASE_CONVERT:
18062 {
18065 }
18066 /* FALLTHRU */
18070 }
18071 }
18072 }
18073 else
18075 }
18077 {
18083 }
18084 else
18088 {
18094 NULL_TREE);
18095 else
18097 }
18100 {
18107 {
18112 }
18115 }
18125 {
18127 {
18128 /* Declare the variable, but don't let that initialize it. */
18133 }
18136 {
18140 {
18149 }
18150 else
18154 {
18159 }
18160 else
18164 }
18170 }
18173 {
18174 /* Declare and initialize the variable. */
18177 }
18179 {
18184 {
18186 {
18192 {
18195 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
18200 }
18203 {
18205 decl);
18207 }
18210 {
18212 decl);
18214 }
18215 else
18217 }
18220 }
18222 {
18225 ? OMP_CLAUSE_LASTPRIVATE
18230 {
18233 }
18234 }
18235 }
18238 {
18242 }
18243 else
18247 {
18258 {
18266 }
18267 else
18273 {
18279 }
18283 {
18291 }
18292 else
18298 }
18307 #undef RECUR
18308 }
18310 /* Helper function of tsubst_expr, find OMP_TEAMS inside
18311 of OMP_TARGET's body. */
18313 static tree
18315 {
18318 {
18327 }
18329 }
18331 /* Helper function for tsubst_expr. For decomposition declaration
18332 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
18333 also the corresponding decls representing the identifiers
18334 of the decomposition declaration. Return DECL if successful
18335 or error_mark_node otherwise, set *FIRST to the first decl
18336 in the list chained through DECL_CHAIN and *CNT to the number
18337 of such decls. */
18339 static tree
18343 {
18348 decl2
18353 {
18355 {
18358 }
18370 else
18371 {
18375 }
18382 {
18385 }
18386 else
18388 }
18391 }
18393 /* Return the proper local_specialization for init-capture pack DECL. */
18395 static tree
18397 {
18398 /* We handle normal pack captures by forwarding to the specialization of the
18399 captured parameter. We can't do that for pack init-captures; we need them
18400 to have their own local_specialization. We created the individual
18401 VAR_DECLs (if any) under build_capture_proxy, and we need to collect them
18402 when we process the DECL_EXPR for the pack init-capture in the template.
18403 So, how do we find them? We don't know the capture proxy pack when
18404 building the individual resulting proxies, and we don't know the
18405 individual proxies when instantiating the pack. What we have in common is
18406 the FIELD_DECL.
18408 So...when we instantiate the FIELD_DECL, we stick the result in
18409 local_specializations. Then at the DECL_EXPR we look up that result, see
18410 how many elements it has, synthesize the names, and look them up. */
18424 {
18429 }
18431 {
18436 else
18438 }
18440 }
18442 /* Like tsubst_copy for expressions, etc. but also does semantic
18443 processing. */
18445 tree
18448 {
18449 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
18450 #define RECUR(NODE) \
18451 tsubst_expr ((NODE), args, complain, in_decl, \
18452 integral_constant_expression_p)
18455 tree r;
18456 location_t loc;
18468 {
18470 {
18474 }
18503 else
18512 {
18514 tree init;
18520 {
18523 {
18527 {
18532 }
18534 }
18535 else
18536 {
18537 /* This is a non-dependent using-decl, and we'll have
18538 used the names it found during template parsing. We do
18539 not want to do the lookup again, because we might not
18540 find the things we found then. */
18543 /* We still need to push the bindings so that we can look up
18544 this name later. */
18547 }
18548 }
18551 {
18552 /* We're in tsubst_lambda_expr, we've already inserted a new
18553 capture proxy, so look it up and register it. */
18554 tree inst;
18556 {
18560 }
18562 {
18563 inst = (retrieve_local_specialization
18567 }
18568 else
18573 }
18580 /* Don't copy the old closure; we'll create a new one in
18581 tsubst_lambda_expr. */
18583 else
18584 {
18588 {
18589 /* By marking the declaration as instantiated, we avoid
18590 trying to instantiate it. Since instantiate_decl can't
18591 handle local variables, and since we've already done
18592 all that needs to be done, that's the right thing to
18593 do. */
18598 /* Anonymous aggregates are a special case. */
18601 {
18604 {
18608 }
18610 }
18615 {
18623 }
18624 else
18625 {
18642 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
18648 /* In a non-template function, VLA type declarations are
18649 handled in grokdeclarator; for templates, handle them
18650 now. */
18654 {
18658 asmspec_tree
18662 }
18668 }
18669 }
18670 }
18673 }
18683 {
18687 }
18692 {
18693 /* Construct another range_for, if this is not a final
18694 substitution (for inside a generic lambda of a
18695 template). Otherwise convert to a regular for. */
18697 stmt = (processing_template_decl
18714 {
18720 }
18721 else
18722 {
18728 }
18734 }
18741 {
18745 }
18751 {
18755 }
18771 {
18772 /* We're partially instantiating a generic lambda, but the condition
18773 of the constexpr if is still dependent. Don't substitute into the
18774 branches now, just remember the template arguments. */
18782 }
18786 {
18791 }
18792 else
18793 {
18801 }
18807 {
18817 }
18825 else
18833 else
18854 {
18860 {
18865 }
18866 }
18870 {
18872 tree label;
18879 }
18885 /* Computed goto's must be tsubst'd into. On the other hand,
18886 non-computed gotos must not be; the identifier in question
18887 will have no binding. */
18889 else
18895 {
18912 }
18917 {
18922 }
18923 else
18924 {
18929 else
18936 else
18942 else
18944 }
18948 {
18952 {
18954 /* Prevent instantiate_decl from trying to instantiate
18955 this variable. We've already done all that needs to be
18956 done. */
18959 }
18964 }
18970 {
18971 /* Local classes are not independent templates; they are
18972 instantiated along with their containing function. And this
18973 way we don't have to deal with pushing out of one local class
18974 to instantiate a member of another local class. */
18975 /* Closures are handled by the LAMBDA_EXPR. */
18985 }
18989 {
18990 tree condition;
18993 condition =
18995 args,
19004 }
19011 in_decl);
19033 {
19040 }
19056 {
19070 in_decl);
19072 {
19079 }
19090 any_range_for
19094 integral_constant_expression_p);
19098 {
19107 }
19108 else
19113 else
19120 else
19121 {
19129 }
19132 t));
19134 }
19140 /* FALLTHRU */
19150 in_decl);
19152 {
19157 }
19158 else
19159 {
19163 }
19168 {
19170 "%<#pragma omp critical%> with %<hint%> clause requires "
19173 }
19184 {
19187 {
19192 }
19193 else
19194 {
19198 }
19200 }
19201 else
19203 OMP_CLAUSE_DEPEND_SOURCE,
19212 ? C_ORT_ACC
19231 {
19234 /* For combined target teams, ensure the num_teams and
19235 thread_limit clause expressions are evaluated on the host,
19236 before entering the target construct. */
19245 {
19248 tf_none);
19255 OMP_CLAUSE_FIRSTPRIVATE);
19259 }
19260 }
19308 /* FALLTHRU */
19326 {
19332 {
19335 }
19337 {
19341 {
19344 }
19349 }
19350 else
19351 {
19354 }
19359 }
19360 else
19361 {
19368 {
19371 }
19374 {
19379 {
19382 }
19384 {
19388 {
19391 }
19396 }
19397 else
19398 {
19401 }
19405 }
19406 else
19407 {
19411 }
19415 }
19419 {
19425 {
19429 {
19434 }
19438 }
19439 else
19440 {
19445 }
19446 }
19450 {
19454 }
19467 /* If the first operand was a statement, we're done with it. */
19472 complain));
19489 integral_constant_expression_p));
19490 }
19493 out:
19496 #undef RECUR
19497 #undef RETURN
19498 }
19500 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
19501 function. For description of the body see comment above
19502 cp_parser_omp_declare_reduction_exprs. */
19504 static void
19506 {
19512 tree_stmt_iterator tsi;
19523 {
19530 /* tsubsting a local var_decl leaves DECL_CONTEXT null, as we
19531 expect to be pushing it. */
19543 }
19545 {
19565 }
19566 }
19568 /* T is a postfix-expression that is not being used in a function
19569 call. Return the substituted version of T. */
19571 static tree
19573 tsubst_flags_t complain,
19574 tree in_decl)
19575 {
19579 else
19585 }
19587 /* Subroutine of tsubst_lambda_expr: add the FIELD/INIT capture pair to the
19588 LAMBDA_EXPR_CAPTURE_LIST passed in LIST. Do deduction for a previously
19589 dependent init-capture. */
19591 static void
19593 tsubst_flags_t complain)
19594 {
19596 {
19599 {
19603 }
19610 }
19612 }
19614 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
19615 instantiation context. Instantiating a pack expansion containing a lambda
19616 might result in multiple lambdas all based on the same lambda in the
19617 template. */
19619 tree
19621 {
19636 else
19647 {
19652 else
19665 {
19666 /* For a VLA, simply tsubsting the field type won't work, we need to
19667 go through add_capture again. XXX do we want to do this for all
19668 captures? */
19669 tree name = (get_identifier
19677 }
19684 {
19685 /* Remember these for when we've pushed local_specializations. */
19688 }
19694 {
19702 complain);
19703 }
19704 else
19705 {
19707 complain);
19711 }
19712 }
19719 {
19720 /* A lambda in a default argument outside a class gets no
19721 LAMBDA_EXPR_EXTRA_SCOPE, as specified by the ABI. But
19722 tsubst_default_argument calls start_lambda_scope, so we need to
19723 specifically ignore it here, and use the global scope. */
19726 /* If we're pushed into another scope (PR105652), fix it. */
19730 }
19731 else
19734 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
19752 else
19753 {
19754 /* The body of a lambda-expression is not a subexpression of the
19755 enclosing expression. Parms are to have DECL_CHAIN tsubsted,
19756 which would be skipped if cp_unevaluated_operand. */
19757 cp_evaluated ev;
19759 /* Fix the type of 'this'. */
19765 {
19768 {
19771 }
19774 }
19775 else
19776 {
19780 {
19783 }
19785 }
19787 /* Let finish_function set this. */
19793 else
19794 /* Still increment function_depth so that we don't GC in the
19795 middle of an expression. */
19805 /* Now record them for lookup_init_capture_pack. */
19808 {
19812 }
19818 {
19819 /* We might not partially instantiate some parts of the function, so
19820 copy these flags from the original template. */
19826 }
19828 /* [temp.deduct] A lambda-expression appearing in a function type or a
19829 template parameter is not considered part of the immediate context for
19830 the purposes of template argument deduction. */
19835 /* We already have a body block from start_lambda_function, we don't
19836 need another to confuse NRV (91217). */
19847 else
19850 /* The capture list was built up in reverse order; fix that now. */
19857 }
19859 out:
19865 }
19867 /* Subroutine of maybe_fold_fn_template_args. */
19869 static bool
19871 {
19874 {
19880 {
19883 }
19888 {
19892 }
19893 }
19896 }
19898 /* Try to do constant evaluation of any explicit template arguments in FN
19899 before overload resolution, to get any errors only once. Return true iff
19900 we didn't have any problems folding. */
19902 static bool
19904 {
19922 }
19924 /* Helper function for tsubst_copy_and_build CALL_EXPR and ARRAY_REF
19925 handling. */
19927 static void
19929 tree in_decl,
19932 {
19935 {
19942 integral_constant_expression_p));
19943 else
19944 {
19945 /* Expand the pack expansion and push each entry onto CALL_ARGS. */
19948 {
19953 {
19958 }
19959 }
19960 else
19961 /* A partial substitution. Add one entry. */
19963 }
19964 }
19965 }
19967 /* Like tsubst but deals with expressions and performs semantic
19968 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)" or
19969 "F<TARGS> (ARGS)". */
19971 tree
19973 tree args,
19974 tsubst_flags_t complain,
19975 tree in_decl,
19978 {
19979 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
19980 #define RECUR(NODE) \
19981 tsubst_copy_and_build (NODE, args, complain, in_decl, \
19983 integral_constant_expression_p)
19986 location_t save_loc;
19995 /* N3276 decltype magic only applies to calls at the top level or on the
19996 right side of a comma. */
20001 {
20004 /* Fall through. */
20006 {
20007 tree decl;
20008 cp_id_kind idk;
20013 {
20016 }
20018 /* Look up the name. */
20021 /* By convention, expressions use ERROR_MARK_NODE to indicate
20022 failure, not NULL_TREE. */
20028 integral_constant_expression_p,
20036 input_location);
20040 {
20044 }
20046 }
20049 {
20050 tree object;
20053 function_p,
20054 integral_constant_expression_p);
20063 {
20068 }
20071 {
20078 /* If we built a function concept check, return the underlying
20079 template-id. So we can evaluate it as a function call. */
20084 }
20087 {
20089 complain);
20092 }
20095 {
20098 }
20099 else
20109 {
20110 /* C++20 P0846: we can encounter an IDENTIFIER_NODE here when
20111 name lookup found nothing when parsing the template name. */
20114 }
20115 else
20117 }
20120 {
20124 {
20125 /* A type conversion to reference type will be enclosed in
20126 such an indirect ref, but the substitution of the cast
20127 will have also added such an indirect ref. */
20129 }
20130 else
20139 }
20142 {
20146 }
20149 {
20153 {
20158 }
20160 /* We'll pass this to convert_nontype_argument again, we don't need
20161 to actually perform any conversion here. */
20169 flags));
20170 }
20173 {
20179 }
20186 {
20187 tree type;
20196 {
20201 }
20209 {
20229 }
20232 }
20235 {
20239 }
20264 /* convert_like should have created an IMPLICIT_CONV_EXPR. */
20275 else
20277 in_decl);
20312 {
20313 /* If either OP0 or OP1 was value- or type-dependent, suppress
20314 warnings that depend on the range of the types involved. */
20324 };
20334 tree r = build_x_binary_op
20336 op0,
20338 ? ERROR_MARK
20340 op1,
20342 ? ERROR_MARK
20351 }
20354 {
20362 }
20378 {
20380 releasing_vec index_exp_list;
20382 integral_constant_expression_p,
20383 index_exp_list);
20385 tree r;
20391 else
20396 }
20405 /* Fall through */
20408 {
20409 tree r;
20417 {
20418 /* When there are no ARGS, we are trying to evaluate a
20419 non-dependent expression from the parser. Trying to do
20420 the substitutions may not work. */
20423 }
20424 else
20425 {
20430 else
20433 /*integral_constant_expression_p=*/
20437 }
20442 else
20447 {
20449 {
20451 {
20455 }
20456 else
20460 }
20462 }
20464 }
20467 {
20477 }
20493 {
20498 tree r = build_x_modify_expr
20502 /* TREE_NO_WARNING must be set if either the expression was
20503 parenthesized or it uses an operator such as >>= rather
20504 than plain assignment. In the former case, it was already
20505 set and must be copied. In the latter case,
20506 build_x_modify_expr sets it and it must not be reset
20507 here. */
20512 }
20517 /* Remember that there was a reference to this entity. */
20524 {
20529 tree ret;
20536 else
20537 {
20541 }
20543 /* If there was an initializer in the original tree, but it
20544 instantiated to an empty list, then we should pass a
20545 non-NULL empty vector to tell build_new that it was an
20546 empty initializer() rather than no initializer. This can
20547 only happen when the initializer is a pack expansion whose
20548 parameter packs are of length zero. */
20553 else
20554 {
20558 else
20559 {
20562 }
20563 }
20565 /* Avoid passing an enclosing decl to valid_array_size_p. */
20572 complain);
20580 }
20583 {
20589 complain));
20590 }
20593 {
20597 integral_constant_expression_p);
20599 op0,
20603 }
20606 {
20607 tree function;
20611 tree ret;
20614 /* Internal function with no arguments. */
20618 /* When we parsed the expression, we determined whether or
20619 not Koenig lookup should be performed. */
20622 {
20625 }
20627 {
20632 }
20637 {
20638 /* Do nothing; calling tsubst_copy_and_build on an identifier
20639 would incorrectly perform unqualified lookup again.
20641 Note that we can also have an IDENTIFIER_NODE if the earlier
20642 unqualified lookup found a member function; in that case
20643 koenig_p will be false and we do want to do the lookup
20644 again to find the instantiated member function.
20646 FIXME but doing that causes c++/15272, so we need to stop
20647 using IDENTIFIER_NODE in that situation. */
20651 /* Use tsubst_copy to substitute through the template arguments
20652 of the template-id without performing unqualified lookup of
20653 the template name. */
20655 }
20656 else
20657 {
20659 {
20665 }
20666 else
20671 /* Avoid error about taking the address of a constructor. */
20676 /* When KOENIG_P, we don't want to mark_used the callee before
20677 augmenting the overload set via ADL, so during this initial
20678 substitution we disable mark_used by setting tf_conv (68942). */
20681 in_decl,
20683 integral_constant_expression_p);
20687 }
20690 releasing_vec call_args;
20692 integral_constant_expression_p,
20693 call_args);
20695 /* Stripped-down processing for a call in a thunk. Specifically, in
20696 the thunk template for a generic lambda. */
20698 {
20699 /* Now that we've expanded any packs, the number of call args
20700 might be different. */
20704 {
20711 }
20712 /* We aren't going to do normal overload resolution, so force the
20713 template-id to resolve. */
20716 {
20717 /* In a thunk, pass through args directly, without any
20718 conversions. */
20723 }
20725 {
20726 /* If there are no other args, just push 'this'. */
20729 else
20730 {
20731 /* Otherwise, shift the other args over to make room. */
20737 }
20738 }
20741 /* The thunk location is not interesting. */
20748 }
20750 /* We do not perform argument-dependent lookup if normal
20751 lookup finds a non-function, in accordance with the
20752 resolution of DR 218. */
20755 /* If lookup found a member function, the Koenig lookup is
20756 not appropriate, even if an unqualified-name was used
20757 to denote the function. */
20760 /* C++20 P0846: Lookup found nothing. */
20763 /* Only do this when substitution turns a dependent call
20764 into a non-dependent call. */
20776 {
20781 {
20782 /* For backwards compatibility and good diagnostics, try
20783 the unqualified lookup again if we aren't in SFINAE
20784 context. */
20785 tree unq = (tsubst_copy_and_build
20787 integral_constant_expression_p));
20792 {
20795 "and no declarations were found by "
20796 "argument-dependent lookup at the point "
20801 /* In a lambda fn, we have to be careful to not
20802 introduce new this captures. Legacy code can't
20803 be using lambdas anyway, so it's ok to be
20804 stricter. Be strict with C++20 template-id ADL too. */
20810 else
20814 {
20825 {
20828 "declarations in dependent base %qT are "
20834 else
20838 }
20839 else
20841 "%qD declared here, later in the "
20845 }
20848 }
20849 }
20851 {
20855 }
20856 }
20858 /* Remember that there was a reference to this entity. */
20867 /* Put back tf_decltype for the actual call. */
20872 {
20876 {
20878 "wrong number of arguments to "
20881 }
20882 else
20890 {
20892 "wrong number of arguments to "
20896 }
20900 complain);
20906 {
20908 complain);
20912 }
20915 /* Unsupported internal function with arguments. */
20917 }
20922 complain);
20924 {
20939 complain);
20940 else
20941 ret = (build_new_method_call
20946 complain));
20947 }
20949 {
20950 /* FUNCTION is a template-id referring to a concept definition. */
20955 /* Calls to standard and variable concepts should have been
20956 previously diagnosed. */
20959 /* Ensure the result is wrapped as a call expression. */
20961 }
20962 else
20965 koenig_p,
20966 complain);
20969 {
20974 {
20979 }
20980 }
20983 }
20986 {
20993 {
20995 {
21000 }
21001 else
21002 {
21007 }
21009 }
21010 else
21011 {
21014 }
21019 }
21022 {
21027 input_location));
21028 }
21034 {
21035 tree object;
21036 tree object_type;
21037 tree member;
21038 tree r;
21042 /* Remember that there was a reference to this entity. */
21053 else
21060 {
21063 }
21065 {
21067 complain);
21071 }
21075 {
21077 {
21082 {
21085 }
21087 {
21092 }
21093 }
21094 }
21097 {
21098 /* Lookup the template functions now that we know what the
21099 scope is. */
21106 {
21109 args);
21110 member = (adjust_result_of_qualified_name_lookup
21112 object_type));
21113 }
21114 else
21115 {
21117 input_location);
21119 }
21120 }
21124 {
21126 {
21130 else
21133 }
21135 }
21139 complain);
21143 }
21150 {
21157 tree r;
21166 /* We do not want to process the index of aggregate
21167 initializers as they are identifier nodes which will be
21168 looked up by digest_init. */
21172 {
21175 }
21180 {
21182 /* An identifier index is looked up in the type
21183 being initialized, not the current scope. */
21188 {
21189 /* Substitute into the pack expansion. */
21191 in_decl);
21195 ;
21197 /* Just move the argument into place. */
21199 else
21200 {
21201 /* Update the length of the final CONSTRUCTOR
21202 arguments vector, and note that we will need to
21203 copy.*/
21206 }
21207 }
21208 else
21210 }
21213 {
21218 {
21220 {
21225 }
21226 else
21228 }
21229 }
21237 {
21242 }
21246 }
21249 {
21252 {
21255 }
21256 else
21257 {
21260 }
21261 }
21266 /* Fall through */
21269 {
21271 /* ??? We're doing a subset of finish_id_expression here. */
21273 /* Replace an evaluated use of the thread_local variable with
21274 a call to its wrapper. */
21280 /* If the original type was a reference, we'll be wrapped in
21281 the appropriate INDIRECT_REF. */
21284 }
21287 {
21291 }
21294 {
21295 tree object_ptr
21302 }
21309 {
21316 }
21319 {
21325 integral_constant_expression_p);
21329 /* If the resulting list of expression statement is empty,
21330 fold it further into void_node. */
21335 }
21338 {
21340 {
21341 /* We don't have a full set of template arguments yet; don't touch
21342 the lambda at all. */
21345 }
21349 }
21353 integral_constant_expression_p));
21358 else
21359 /* Recreate the PAREN_EXPR from __builtin_assoc_barrier. */
21360 {
21364 }
21367 {
21372 complain));
21373 }
21376 {
21379 }
21382 /* No need to substitute further, a RANGE_EXPR will always be built
21383 with constant operands. */
21389 /* We need to do this here as well as in tsubst_copy so we get the
21390 other tsubst_copy_and_build semantics for a PARM_DECL operand. */
21393 /* fallthrough. */
21396 /* Handle Objective-C++ constructs, if appropriate. */
21397 {
21398 tree subst
21403 }
21405 }
21407 #undef RECUR
21408 #undef RETURN
21409 out:
21412 }
21414 /* Verify that the instantiated ARGS are valid. For type arguments,
21415 make sure that the type's linkage is ok. For non-type arguments,
21416 make sure they are constants if they are integral or enumerations.
21417 Emit an error under control of COMPLAIN, and return TRUE on error. */
21419 static bool
21421 {
21425 {
21435 }
21437 {
21438 /* [basic.link]: A name with no linkage (notably, the name
21439 of a class or enumeration declared in a local scope)
21440 shall not be used to declare an entity with linkage.
21441 This implies that names with no linkage cannot be used as
21442 template arguments
21444 DR 757 relaxes this restriction for C++0x. */
21449 {
21450 /* DR 488 makes use of a type with no linkage cause
21451 type deduction to fail. */
21453 {
21456 else
21459 }
21461 }
21462 /* In order to avoid all sorts of complications, we do not
21463 allow variably-modified types as template arguments. */
21465 {
21469 }
21470 }
21471 /* Class template and alias template arguments should be OK. */
21473 ;
21474 /* A non-type argument of integral or enumerated type must be a
21475 constant. */
21480 {
21484 }
21486 }
21488 static bool
21490 {
21495 {
21498 }
21502 }
21504 /* We're out of SFINAE context now, so generate diagnostics for the access
21505 errors we saw earlier when instantiating D from TMPL and ARGS. */
21507 static void
21509 {
21521 }
21523 /* Instantiate the indicated variable, function, or alias template TMPL with
21524 the template arguments in TARG_PTR. */
21526 tree
21528 {
21532 tree fndecl;
21533 tree gen_tmpl;
21534 tree spec;
21545 /* If this function is a clone, handle it specially. */
21547 {
21548 tree spec;
21549 tree clone;
21551 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
21552 DECL_CLONED_FUNCTION. */
21558 /* Look for the clone. */
21562 /* We should always have found the clone by now. */
21565 }
21570 /* Check to see if we already have this specialization. */
21574 /* targ_ptr only has the innermost template args, so add the outer ones
21575 from tmpl, which could be either a partial instantiation or gen_tmpl (in
21576 the case of a non-dependent call within a template definition). */
21577 targ_ptr = (add_outermost_template_args
21579 targ_ptr));
21581 /* It would be nice to avoid hashing here and then again in tsubst_decl,
21582 but it doesn't seem to be on the hot path. */
21586 || ((fndecl
21592 {
21594 {
21598 }
21600 }
21603 complain))
21606 /* We are building a FUNCTION_DECL, during which the access of its
21607 parameters and return types have to be checked. However this
21608 FUNCTION_DECL which is the desired context for access checking
21609 is not built yet. We solve this chicken-and-egg problem by
21610 deferring all checks until we have the FUNCTION_DECL. */
21613 /* Instantiation of the function happens in the context of the function
21614 template, not the context of the overload resolution we're doing. */
21616 /* If there are dependent arguments, e.g. because we're doing partial
21617 ordering, make sure processing_template_decl stays set. */
21621 {
21625 }
21631 {
21632 /* We need to determine if we're using a partial or explicit
21633 specialization now, because the type of the variable could be
21634 different. */
21640 {
21645 }
21646 }
21648 /* Substitute template parameters to obtain the specialization. */
21656 {
21659 }
21661 /* The DECL_TI_TEMPLATE should always be the immediate parent
21662 template, not the most general template. */
21668 /* Now we know the specialization, compute access previously
21669 deferred. Do no access control for inheriting constructors,
21670 as we already checked access for the inherited constructor. */
21673 {
21678 }
21681 /* If we've just instantiated the main entry point for a function,
21682 instantiate all the alternate entry points as well. We do this
21683 by cloning the instantiation of the main entry point, not by
21684 instantiating the template clones. */
21690 {
21692 {
21693 /* Remember to reinstantiate when we're out of SFINAE so the user
21694 can see the errors. */
21696 }
21698 }
21700 }
21702 /* Instantiate the alias template TMPL with ARGS. Also push a template
21703 instantiation level, which instantiate_template doesn't do because
21704 functions and variables have sufficient context established by the
21705 callers. */
21707 static tree
21709 {
21713 args =
21719 /* FIXME check for satisfaction in check_instantiated_args. */
21723 {
21725 {
21726 auto_diagnostic_group d;
21729 }
21731 }
21739 {
21740 /* An alias template specialization can be dependent
21741 even if its underlying type is not. */
21744 /* Sometimes a dependent alias spec is equivalent to its expansion,
21745 sometimes not. So always use structural_comptypes. */
21747 }
21750 }
21752 /* PARM is a template parameter pack for FN. Returns true iff
21753 PARM is used in a deducible way in the argument list of FN. */
21755 static bool
21757 {
21760 {
21762 tree packs;
21768 {
21769 /* The template parameter pack is used in a function parameter
21770 pack. If this is the end of the parameter list, the
21771 template parameter pack is deducible. */
21774 else
21775 /* Otherwise, not. Well, it could be deduced from
21776 a non-pack parameter, but doing so would end up with
21777 a deduction mismatch, so don't bother. */
21779 }
21780 }
21781 /* The template parameter pack isn't used in any function parameter
21782 packs, but it might be used deeper, e.g. tuple<Args...>. */
21784 }
21786 /* Subroutine of fn_type_unification: check non-dependent parms for
21787 convertibility. */
21789 static int
21793 {
21794 /* Non-constructor methods need to leave a conversion for 'this', which
21795 isn't included in nargs here. */
21801 {
21807 /* For a function parameter pack that occurs at the end of the
21808 parameter-declaration-list, the type A of each remaining
21809 argument of the call is compared with the type P of the
21810 declarator-id of the function parameter pack. */
21816 /* For a function parameter pack that does not occur at the
21817 end of the parameter-declaration-list, the type of the
21818 parameter pack is a non-deduced context. */
21822 {
21830 }
21833 }
21836 }
21838 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
21839 NARGS elements of the arguments that are being used when calling
21840 it. TARGS is a vector into which the deduced template arguments
21841 are placed.
21843 Returns either a FUNCTION_DECL for the matching specialization of FN or
21844 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
21845 true, diagnostics will be printed to explain why it failed.
21847 If FN is a conversion operator, or we are trying to produce a specific
21848 specialization, RETURN_TYPE is the return type desired.
21850 The EXPLICIT_TARGS are explicit template arguments provided via a
21851 template-id.
21853 The parameter STRICT is one of:
21855 DEDUCE_CALL:
21856 We are deducing arguments for a function call, as in
21857 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
21858 deducing arguments for a call to the result of a conversion
21859 function template, as in [over.call.object].
21861 DEDUCE_CONV:
21862 We are deducing arguments for a conversion function, as in
21863 [temp.deduct.conv].
21865 DEDUCE_EXACT:
21866 We are deducing arguments when doing an explicit instantiation
21867 as in [temp.explicit], when determining an explicit specialization
21868 as in [temp.expl.spec], or when taking the address of a function
21869 template, as in [temp.deduct.funcaddr]. */
21871 tree
21873 tree explicit_targs,
21874 tree targs,
21877 tree return_type,
21878 unification_kind_t strict,
21883 {
21884 tree parms;
21885 tree fntype;
21890 /* type_unification_real will pass back any access checks from default
21891 template argument substitution. */
21893 /* We don't have all the template args yet. */
21906 full_targs = (add_outermost_template_args
21908 targs));
21913 /* In C++0x, it's possible to have a function template whose type depends
21914 on itself recursively. This is most obvious with decltype, but can also
21915 occur with enumeration scope (c++/48969). So we need to catch infinite
21916 recursion and reject the substitution at deduction time; this function
21917 will return error_mark_node for any repeated substitution.
21919 This also catches excessive recursion such as when f<N> depends on
21920 f<N-1> across all integers, and returns error_mark_node for all the
21921 substitutions back up to the initial one.
21923 This is, of course, not reentrant. */
21932 {
21933 /* [temp.deduct]
21935 The specified template arguments must match the template
21936 parameters in kind (i.e., type, nontype, template), and there
21937 must not be more arguments than there are parameters;
21938 otherwise type deduction fails.
21940 Nontype arguments must match the types of the corresponding
21941 nontype template parameters, or must be convertible to the
21942 types of the corresponding nontype parameters as specified in
21943 _temp.arg.nontype_, otherwise type deduction fails.
21945 All references in the function type of the function template
21946 to the corresponding template parameters are replaced by the
21947 specified template argument values. If a substitution in a
21948 template parameter or in the function type of the function
21949 template results in an invalid type, type deduction fails. */
21960 explicit_targs);
21962 /* Adjust any explicit template arguments before entering the
21963 substitution context. */
21964 explicit_targs
21972 /* Substitute the explicit args into the function type. This is
21973 necessary so that, for instance, explicitly declared function
21974 arguments can match null pointed constants. If we were given
21975 an incomplete set of explicit args, we must not do semantic
21976 processing during substitution as we could create partial
21977 instantiations. */
21979 {
21984 /* Dig out the actual parm. */
21987 {
21990 }
21992 {
21995 }
21998 /* No explicit argument for this template parameter. */
22001 {
22002 /* Mark the argument pack as "incomplete". We could
22003 still deduce more arguments during unification.
22004 We remove this mark in type_unification_real. */
22009 /* We have some incomplete argument packs. */
22011 }
22012 }
22015 {
22017 {
22020 }
22023 /* Ignore any access checks; we'll see them again in
22024 instantiate_template and they might have the wrong
22025 access path at this point. */
22036 }
22038 /* Place the explicitly specified arguments in TARGS. */
22044 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
22046 }
22049 {
22055 }
22060 /* Never do unification on the 'this' parameter. */
22064 {
22065 /* We're deducing for a call to the result of a template conversion
22066 function. The parms we really want are in return_type. */
22070 }
22072 {
22074 }
22076 /* We allow incomplete unification without an error message here
22077 because the standard doesn't seem to explicitly prohibit it. Our
22078 callers must be ready to deal with unification failures in any
22079 event. */
22081 /* If we aren't explaining yet, push tinst context so we can see where
22082 any errors (e.g. from class instantiations triggered by instantiation
22083 of default template arguments) come from. If we are explaining, this
22084 context is redundant. */
22086 {
22089 }
22099 /* Now that we have bindings for all of the template arguments,
22100 ensure that the arguments deduced for the template template
22101 parameters have compatible template parameter lists. We cannot
22102 check this property before we have deduced all template
22103 arguments, because the template parameter types of a template
22104 template parameter might depend on prior template parameters
22105 deduced after the template template parameter. The following
22106 ill-formed example illustrates this issue:
22108 template<typename T, template<T> class C> void f(C<5>, T);
22110 template<int N> struct X {};
22112 void g() {
22113 f(X<5>(), 5l); // error: template argument deduction fails
22114 }
22116 The template parameter list of 'C' depends on the template type
22117 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
22118 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
22119 time that we deduce 'C'. */
22122 {
22125 }
22127 deduced:
22129 /* CWG2369: Check satisfaction before non-deducible conversions. */
22131 {
22135 }
22137 /* DR 1391: All parameters have args, now check non-dependent parms for
22138 convertibility. We don't do this if all args were explicitly specified,
22139 as the standard says that we substitute explicit args immediately. */
22145 /* All is well so far. Now, check:
22147 [temp.deduct]
22149 When all template arguments have been deduced, all uses of
22150 template parameters in nondeduced contexts are replaced with
22151 the corresponding deduced argument values. If the
22152 substitution results in an invalid type, as described above,
22153 type deduction fails. */
22155 {
22158 }
22160 /* Also collect access checks from the instantiation. */
22173 /* Now perform any access checks encountered during substitution. */
22180 /* If we're looking for an exact match, check that what we got
22181 is indeed an exact match. It might not be if some template
22182 parameters are used in non-deduced contexts. But don't check
22183 for an exact match if we have dependent template arguments;
22184 in that case we're doing partial ordering, and we already know
22185 that we have two candidates that will provide the actual type. */
22187 {
22191 tree sarg
22197 {
22201 }
22203 /* add_candidates uses DEDUCE_EXACT for x.operator foo(), but args
22204 doesn't contain the trailing void, and conv fns are always (). */
22206 {
22210 }
22211 }
22213 /* After doing deduction with the inherited constructor, actually return an
22214 instantiation of the inheriting constructor. */
22220 fail:
22223 {
22225 /* Reset once we're all the way out. */
22227 }
22230 }
22232 /* Returns true iff PARM is a forwarding reference in the context of
22233 template argument deduction for TMPL. */
22235 static bool
22237 {
22238 /* [temp.deduct.call], "A forwarding reference is an rvalue reference to a
22239 cv-unqualified template parameter ..." */
22244 {
22246 /* [temp.deduct.call], "... that does not represent a template parameter
22247 of a class template (during class template argument deduction)." */
22251 {
22252 /* Since the template parameters of a synthesized guide consist of
22253 the template parameters of the class template followed by those of
22254 the constructor (if any), we can tell if PARM represents a template
22255 parameter of the class template by comparing its index with the
22256 arity of the class template. */
22261 }
22263 }
22265 }
22267 /* Adjust types before performing type deduction, as described in
22268 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
22269 sections are symmetric. PARM is the type of a function parameter
22270 or the return type of the conversion function. ARG is the type of
22271 the argument passed to the call, or the type of the value
22272 initialized with the result of the conversion function.
22273 ARG_EXPR is the original argument expression, which may be null. */
22275 static int
22277 unification_kind_t strict,
22280 tree arg_expr)
22281 {
22285 {
22290 /* Swap PARM and ARG throughout the remainder of this
22291 function; the handling is precisely symmetric since PARM
22292 will initialize ARG rather than vice versa. */
22297 /* Core issue #873: Do the DR606 thing (see below) for these cases,
22298 too, but here handle it by stripping the reference from PARM
22299 rather than by adding it to ARG. */
22304 /* Nothing else to do in this case. */
22309 }
22312 {
22313 /* [temp.deduct.call]
22315 If P is not a reference type:
22317 --If A is an array type, the pointer type produced by the
22318 array-to-pointer standard conversion (_conv.array_) is
22319 used in place of A for type deduction; otherwise,
22321 --If A is a function type, the pointer type produced by
22322 the function-to-pointer standard conversion
22323 (_conv.func_) is used in place of A for type deduction;
22324 otherwise,
22326 --If A is a cv-qualified type, the top level
22327 cv-qualifiers of A's type are ignored for type
22328 deduction. */
22333 else
22335 }
22337 /* [temp.deduct.call], "If P is a forwarding reference and the argument is
22338 an lvalue, the type 'lvalue reference to A' is used in place of A for
22339 type deduction." */
22342 /* try_one_overload doesn't provide an arg_expr, but
22343 functions are always lvalues. */
22347 /* [temp.deduct.call]
22349 If P is a cv-qualified type, the top level cv-qualifiers
22350 of P's type are ignored for type deduction. If P is a
22351 reference type, the type referred to by P is used for
22352 type deduction. */
22355 {
22358 }
22360 /* DR 322. For conversion deduction, remove a reference type on parm
22361 too (which has been swapped into ARG). */
22366 }
22368 /* Subroutine of fn_type_unification. PARM is a function parameter of a
22369 template which doesn't contain any deducible template parameters; check if
22370 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
22371 unify_one_argument. */
22373 static int
22377 {
22378 tree type;
22382 else
22390 {
22393 }
22395 {
22399 /* Avoid recalculating this in add_function_candidate. */
22400 ok = (*conv_p
22402 else
22406 }
22410 else
22412 }
22416 /* Returns true iff the expression EXPR is one from which a template
22417 argument can be deduced. In other words, if it's an undecorated
22418 use of a template non-type parameter. */
22420 static bool
22422 {
22423 /* Strip implicit conversions and implicit INDIRECT_REFs. */
22429 }
22431 /* Returns true iff the array domain DOMAIN uses a template parameter in a
22432 deducible way; that is, if it has a max value of <PARM> - 1. */
22434 static bool
22436 {
22445 }
22447 /* Returns true iff the template arguments ARGS use a template parameter
22448 in a deducible way. */
22450 static bool
22452 {
22454 {
22458 else
22459 {
22466 else
22468 }
22471 }
22473 }
22475 /* Returns true iff TYPE contains any deducible references to template
22476 parameters, as per 14.8.2.5. */
22478 static bool
22480 {
22484 /* T
22485 cv-list T
22486 TT<T>
22487 TT<i>
22488 TT<> */
22493 /* T*
22494 T&
22495 T&& */
22499 /* T[integer-constant ]
22500 type [i] */
22505 /* T type ::*
22506 type T::*
22507 T T::*
22508 T (type ::*)()
22509 type (T::*)()
22510 type (type ::*)(T)
22511 type (T::*)(T)
22512 T (type ::*)(T)
22513 T (T::*)()
22514 T (T::*)(T) */
22517 || (uses_deducible_template_parms
22520 /* template-name <T> (where template-name refers to a class template)
22521 template-name <i> (where template-name refers to a class template) */
22528 /* type (T)
22529 T()
22530 T(T) */
22532 {
22546 }
22549 }
22551 /* Subroutine of type_unification_real and unify_pack_expansion to
22552 handle unification of a single P/A pair. Parameters are as
22553 for those functions. */
22555 static int
22559 {
22566 /* We can't deduce anything from this, but we might get all the
22567 template args from other function args. */
22570 /* Implicit conversions (Clause 4) will be performed on a function
22571 argument to convert it to the type of the corresponding function
22572 parameter if the parameter type contains no template-parameters that
22573 participate in template argument deduction. */
22576 /* For function parameters with no deducible template parameters,
22577 just return. We'll check non-dependent conversions later. */
22581 {
22583 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
22584 | UNIFY_ALLOW_MORE_CV_QUAL
22598 }
22600 /* We only do these transformations if this is the top-level
22601 parameter_type_list in a call or declaration matching; in other
22602 situations (nested function declarators, template argument lists) we
22603 won't be comparing a type to an expression, and we don't do any type
22604 adjustments. */
22606 {
22608 {
22611 {
22612 /* [temp.deduct.type] A template-argument can be
22613 deduced from a pointer to function or pointer
22614 to member function argument if the set of
22615 overloaded functions does not contain function
22616 templates and at most one of a set of
22617 overloaded functions provides a unique
22618 match. */
22622 /* If a unique match was not found, this is a
22623 non-deduced context, so we still succeed. */
22625 }
22631 }
22635 }
22636 else
22641 /* For deduction from an init-list we need the actual list. */
22645 }
22647 /* for_each_template_parm callback that always returns 0. */
22649 static int
22651 {
22653 }
22655 /* for_each_template_parm any_fn callback to handle deduction of a template
22656 type argument from the type of an array bound. */
22658 static int
22660 {
22668 {
22674 }
22676 /* Keep walking. */
22678 }
22680 /* Try to deduce any not-yet-deduced template type arguments from the type of
22681 an array bound. This is handled separately from unify because 14.8.2.5 says
22682 "The type of a type parameter is only deduced from an array bound if it is
22683 not otherwise deduced." */
22685 static void
22687 {
22692 }
22694 /* Most parms like fn_type_unification.
22696 If SUBR is 1, we're being called recursively (to unify the
22697 arguments of a function or method parameter of a function
22698 template).
22700 CHECKS is a pointer to a vector of access checks encountered while
22701 substituting default template arguments. */
22703 static int
22705 tree full_targs,
22706 tree xparms,
22710 unification_kind_t strict,
22713 {
22718 tree parms;
22729 /* Reset the number of non-defaulted template arguments contained
22730 in TARGS. */
22733 again:
22738 /* Only fn_type_unification cares about terminal void. */
22745 {
22750 /* For a function parameter pack that occurs at the end of the
22751 parameter-declaration-list, the type A of each remaining
22752 argument of the call is compared with the type P of the
22753 declarator-id of the function parameter pack. */
22759 /* For a function parameter pack that does not occur at the
22760 end of the parameter-declaration-list, the type of the
22761 parameter pack is a non-deduced context. */
22768 explain_p))
22770 }
22775 {
22776 /* Unify the remaining arguments with the pack expansion type. */
22777 tree argvec;
22780 /* Allocate a TREE_VEC and copy in all of the arguments */
22785 /* Copy the parameter into parmvec. */
22791 /* Advance to the end of the list of parameters. */
22793 }
22795 /* Fail if we've reached the end of the parm list, and more args
22796 are present, and the parm list isn't variadic. */
22799 /* Fail if parms are left and they don't have default values and
22800 they aren't all deduced as empty packs (c++/57397). This is
22801 consistent with sufficient_parms_p. */
22804 {
22808 do
22809 {
22812 count++;
22814 }
22818 type_pack_p);
22819 }
22822 {
22823 tsubst_flags_t complain = (explain_p
22824 ? tf_warning_or_error
22829 {
22833 /* Clear the "incomplete" flags on all argument packs now so that
22834 substituting them into later default arguments works. */
22836 {
22839 }
22847 {
22852 }
22854 /* If this is an undeduced nontype parameter that depends on
22855 a type parameter, try another pass; its type may have been
22856 deduced from a later argument than the one from which
22857 this parameter can be deduced. */
22861 {
22864 }
22866 /* Core issue #226 (C++0x) [temp.deduct]:
22868 If a template argument has not been deduced, its
22869 default template argument, if any, is used.
22871 When we are in C++98 mode, TREE_PURPOSE will either
22872 be NULL_TREE or ERROR_MARK_NODE, so we do not need
22873 to explicitly check cxx_dialect here. */
22875 /* OK, there is a default argument. Wait until after the
22876 conversion check to do substitution. */
22879 /* If the type parameter is a parameter pack, then it will
22880 be deduced to an empty parameter pack. */
22882 {
22883 tree arg;
22886 {
22889 }
22890 else
22897 }
22900 }
22902 /* Now substitute into the default template arguments. */
22904 {
22920 {
22921 /* The type of this non-type parameter depends on undeduced
22922 parameters. Don't try to use its default argument yet,
22923 since we might deduce an argument for it on the next pass,
22924 but do check whether the arguments we already have cause
22925 substitution failure, so that that happens before we try
22926 later default arguments (78489). */
22929 NULL_TREE);
22933 else
22935 }
22936 else
22937 {
22938 /* Even if the call is happening in template context, getting
22939 here means it's non-dependent, and a default argument is
22940 considered a separate definition under [temp.decls], so we can
22941 do this substitution without processing_template_decl. This
22942 is important if the default argument contains something that
22943 might be instantiation-dependent like access (87480). */
22944 processing_template_decl_sentinel s;
22947 {
22948 /* First instatiate in template context, in case we still
22949 depend on undeduced template parameters. */
22952 NULL_TREE);
22956 /* We replaced all the tparms, substitute again out of
22957 template context. */
22959 }
22962 NULL_TREE);
22969 else
22971 }
22980 {
22982 /* The position of the first default template argument,
22983 is also the number of non-defaulted arguments in TARGS.
22984 Record that. */
22987 }
22988 }
22992 }
22998 }
23000 /* Subroutine of type_unification_real. Args are like the variables
23001 at the call site. ARG is an overloaded function (or template-id);
23002 we try deducing template args from each of the overloads, and if
23003 only one succeeds, we go with that. Modifies TARGS and returns
23004 true on success. */
23006 static bool
23008 tree targs,
23009 tree parm,
23010 tree arg,
23011 unification_kind_t strict,
23014 {
23021 {
23024 }
23025 else
23029 /* Handle `&x' where `x' is some static or non-static member
23030 function name. */
23036 /* Strip baselink information. */
23041 {
23042 /* If we got some explicit template args, we need to plug them into
23043 the affected templates before we try to unify, in case the
23044 explicit args will completely resolve the templates in question. */
23051 {
23064 {
23069 {
23070 /* Instantiate the function to deduce its return type. */
23074 }
23083 {
23086 }
23087 }
23090 }
23091 /* If no templates (or more than one) are fully resolved by the
23092 explicit arguments, this template-id is a non-deduced context; it
23093 could still be OK if we deduce all template arguments for the
23094 enclosing call through other arguments. */
23097 }
23099 /* If ARG is, for example, "(0, &f)" then its type will be unknown
23100 -- but the deduction does not succeed because the expression is
23101 not just the function on its own. */
23103 else
23105 {
23110 {
23113 }
23114 }
23116 /* [temp.deduct.type] A template-argument can be deduced from a pointer
23117 to function or pointer to member function argument if the set of
23118 overloaded functions does not contain function templates and at most
23119 one of a set of overloaded functions provides a unique match.
23121 So if we found multiple possibilities, we return success but don't
23122 deduce anything. */
23125 {
23129 {
23134 /* Don't forget explicit template arguments in a pack. */
23138 }
23139 }
23144 }
23146 /* Core DR 115: In contexts where deduction is done and fails, or in
23147 contexts where deduction is not done, if a template argument list is
23148 specified and it, along with any default template arguments, identifies
23149 a single function template specialization, then the template-id is an
23150 lvalue for the function template specialization. */
23152 tree
23154 {
23167 {
23170 }
23172 {
23175 }
23177 {
23180 }
23183 {
23187 /* If we got some explicit template args, we need to plug them into
23188 the affected templates before we try to unify, in case the
23189 explicit args will completely resolve the templates in question. */
23197 {
23210 {
23213 {
23216 }
23219 {
23222 }
23223 }
23224 }
23226 {
23234 {
23235 tree base
23238 }
23242 }
23244 /* There were no good options and at least one bad one, so let the
23245 user know what the problem is. */
23247 }
23249 }
23251 /* As above, but error out if the expression remains overloaded. */
23253 tree
23255 {
23258 {
23262 }
23264 }
23266 /* Subroutine of resolve_overloaded_unification; does deduction for a single
23267 overload. Fills TARGS with any deduced arguments, or error_mark_node if
23268 different overloads deduce different arguments for a given parm.
23269 ADDR_P is true if the expression for which deduction is being
23270 performed was of the form "& fn" rather than simply "fn".
23272 Returns 1 on success. */
23274 static int
23276 tree orig_targs,
23277 tree targs,
23278 tree parm,
23279 tree arg,
23280 unification_kind_t strict,
23284 {
23286 tree tempargs;
23292 /* [temp.deduct.type] A template-argument can be deduced from a pointer
23293 to function or pointer to member function argument if the set of
23294 overloaded functions does not contain function templates and at most
23295 one of a set of overloaded functions provides a unique match.
23297 So if this is a template, just return success. */
23310 /* We don't copy orig_targs for this because if we have already deduced
23311 some template args from previous args, unify would complain when we
23312 try to deduce a template parameter for the same argument, even though
23313 there isn't really a conflict. */
23320 /* First make sure we didn't deduce anything that conflicts with
23321 explicitly specified args. */
23323 {
23330 /* Since we're unifying against ourselves, we will fill in
23331 template args used in the function parm list with our own
23332 template parms. Discard them. */
23335 {
23336 /* Check that the argument at each index of the deduced argument pack
23337 is equivalent to the corresponding explicitly specified argument.
23338 We may have deduced more arguments than were explicitly specified,
23339 and that's OK. */
23341 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
23342 that's wrong if we deduce the same argument pack from multiple
23343 function arguments: it's only incomplete the first time. */
23356 }
23359 }
23362 {
23367 }
23370 }
23372 /* PARM is a template class (perhaps with unbound template
23373 parameters). ARG is a fully instantiated type. If ARG can be
23374 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
23375 TARGS are as for unify. */
23377 static tree
23380 {
23389 /* We need to make a new template argument vector for the call to
23390 unify. If we used TARGS, we'd clutter it up with the result of
23391 the attempted unification, even if this class didn't work out.
23392 We also don't want to commit ourselves to all the unifications
23393 we've already done, since unification is supposed to be done on
23394 an argument-by-argument basis. In other words, consider the
23395 following pathological case:
23397 template <int I, int J, int K>
23398 struct S {};
23400 template <int I, int J>
23401 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
23403 template <int I, int J, int K>
23404 void f(S<I, J, K>, S<I, I, I>);
23406 void g() {
23407 S<0, 0, 0> s0;
23408 S<0, 1, 2> s2;
23410 f(s0, s2);
23411 }
23413 Now, by the time we consider the unification involving `s2', we
23414 already know that we must have `f<0, 0, 0>'. But, even though
23415 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
23416 because there are two ways to unify base classes of S<0, 1, 2>
23417 with S<I, I, I>. If we kept the already deduced knowledge, we
23418 would reject the possibility I=1. */
23426 else
23436 }
23438 /* Given a template type PARM and a class type ARG, find the unique
23439 base type in ARG that is an instance of PARM. We do not examine
23440 ARG itself; only its base-classes. If there is not exactly one
23441 appropriate base class, return NULL_TREE. PARM may be the type of
23442 a partial specialization, as well as a plain template type. Used
23443 by unify. */
23445 static enum template_base_result
23448 {
23450 tree binfo;
23456 {
23457 /* The type could not be completed. */
23460 }
23462 /* Walk in inheritance graph order. The search order is not
23463 important, and this avoids multiple walks of virtual bases. */
23465 {
23470 {
23471 /* If there is more than one satisfactory baseclass, then:
23473 [temp.deduct.call]
23475 If they yield more than one possible deduced A, the type
23476 deduction fails.
23478 applies. */
23480 {
23481 /* [temp.deduct.call]/4.3: If there is a class C that is a
23482 (direct or indirect) base class of D and derived (directly or
23483 indirectly) from a class B and that would be a valid deduced
23484 A, the deduced A cannot be B or pointer to B, respectively. */
23486 /* Ignore r. */
23490 else
23491 {
23494 }
23495 }
23498 }
23499 }
23503 }
23505 /* Returns the level of DECL, which declares a template parameter. */
23507 static int
23509 {
23511 {
23521 }
23523 }
23525 /* Decide whether ARG can be unified with PARM, considering only the
23526 cv-qualifiers of each type, given STRICT as documented for unify.
23527 Returns nonzero iff the unification is OK on that basis. */
23529 static int
23531 {
23537 {
23538 /* Although a CVR qualifier is ignored when being applied to a
23539 substituted template parameter ([8.3.2]/1 for example), that
23540 does not allow us to unify "const T" with "int&" because both
23541 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
23542 It is ok when we're allowing additional CV qualifiers
23543 at the outer level [14.8.2.1]/3,1st bullet. */
23552 }
23563 }
23565 /* Determines the LEVEL and INDEX for the template parameter PARM. */
23566 void
23568 {
23572 {
23575 }
23576 else
23577 {
23580 }
23581 }
23583 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
23584 do { \
23585 if (unify (TP, TA, P, A, S, EP)) \
23586 return 1; \
23587 } while (0)
23589 /* Unifies the remaining arguments in PACKED_ARGS with the pack
23590 expansion at the end of PACKED_PARMS. Returns 0 if the type
23591 deduction succeeds, 1 otherwise. STRICT is the same as in
23592 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
23593 function call argument list. We'll need to adjust the arguments to make them
23594 types. SUBR tells us if this is from a recursive call to
23595 type_unification_real, or for comparing two template argument
23596 lists. */
23598 static int
23602 {
23603 tree parm
23609 /* Add in any args remembered from an earlier partial instantiation. */
23617 /* Determine the parameter packs we will be deducing from the
23618 pattern, and record their current deductions. */
23621 {
23625 /* Only template parameter packs can be deduced, not e.g. function
23626 parameter packs or __bases or __integer_pack. */
23630 /* Determine the index and level of this parameter pack. */
23635 /* Keep track of the parameter packs and their corresponding
23636 argument packs. */
23639 }
23641 /* Loop through all of the arguments that have not yet been
23642 unified and unify each with the pattern. */
23644 {
23645 tree parm;
23649 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
23650 or the element of its argument pack at the current index if
23651 this argument was explicitly specified. */
23653 {
23662 {
23665 }
23667 }
23669 /* If we had explicit template arguments, substitute them into the
23670 pattern before deduction. */
23672 {
23673 /* Some arguments might still be unspecified or dependent. */
23681 NULL_TREE);
23686 }
23687 else
23690 /* Unify the pattern with the current argument. */
23692 explain_p))
23695 /* For each parameter pack, collect the deduced value. */
23697 {
23703 }
23704 }
23706 /* Verify that the results of unification with the parameter packs
23707 produce results consistent with what we've seen before, and make
23708 the deduced argument packs available. */
23710 {
23717 /* By default keep the original deduced argument pack.
23718 If necessary, more specific code is going to update the
23719 resulting deduced argument later down in this function. */
23723 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
23724 actually deduce anything. */
23732 {
23733 /* If we had fewer function args than explicit template args,
23734 just use the explicits. */
23739 }
23742 {
23743 tree result;
23744 /* Build the deduced *_ARGUMENT_PACK. */
23746 {
23749 }
23750 else
23755 /* Note the deduced argument packs for this parameter
23756 pack. */
23758 }
23762 {
23763 /* We only had the explicitly-provided arguments before, but
23764 now we have a complete set of arguments. */
23770 }
23771 else
23772 {
23776 /* During template argument deduction for the aggregate deduction
23777 candidate, the number of elements in a trailing parameter pack
23778 is only deduced from the number of remaining function
23779 arguments if it is not otherwise deduced. */
23786 /* Inconsistent unification of this parameter pack. */
23788 bad_old_arg,
23789 bad_new_arg);
23790 }
23791 }
23794 }
23796 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
23797 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
23798 parameters and return value are as for unify. */
23800 static int
23804 {
23805 tree parm_max;
23806 tree arg_max;
23810 /* Our representation of array types uses "N - 1" as the
23811 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
23812 not an integer constant. We cannot unify arbitrarily
23813 complex expressions, so we eliminate the MINUS_EXPRs
23814 here. */
23818 {
23821 }
23825 {
23826 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
23827 trying to unify the type of a variable with the type
23828 of a template parameter. For example:
23830 template <unsigned int N>
23831 void f (char (&) [N]);
23832 int g();
23833 void h(int i) {
23834 char a[g(i)];
23835 f(a);
23836 }
23838 Here, the type of the ARG will be "int [g(i)]", and
23839 may be a SAVE_EXPR, etc. */
23843 }
23845 /* If only one of the bounds used a MINUS_EXPR, compensate
23846 by adding one to the other bound. */
23849 integer_type_node,
23850 parm_max,
23851 integer_one_node);
23854 integer_type_node,
23855 arg_max,
23856 integer_one_node);
23860 }
23862 /* Returns whether T, a P or A in unify, is a type, template or expression. */
23866 static pa_kind_t
23868 {
23877 else
23879 }
23881 /* Deduce the value of template parameters. TPARMS is the (innermost)
23882 set of template parameters to a template. TARGS is the bindings
23883 for those template parameters, as determined thus far; TARGS may
23884 include template arguments for outer levels of template parameters
23885 as well. PARM is a parameter to a template function, or a
23886 subcomponent of that parameter; ARG is the corresponding argument.
23887 This function attempts to match PARM with ARG in a manner
23888 consistent with the existing assignments in TARGS. If more values
23889 are deduced, then TARGS is updated.
23891 Returns 0 if the type deduction succeeds, 1 otherwise. The
23892 parameter STRICT is a bitwise or of the following flags:
23894 UNIFY_ALLOW_NONE:
23895 Require an exact match between PARM and ARG.
23896 UNIFY_ALLOW_MORE_CV_QUAL:
23897 Allow the deduced ARG to be more cv-qualified (by qualification
23898 conversion) than ARG.
23899 UNIFY_ALLOW_LESS_CV_QUAL:
23900 Allow the deduced ARG to be less cv-qualified than ARG.
23901 UNIFY_ALLOW_DERIVED:
23902 Allow the deduced ARG to be a template base class of ARG,
23903 or a pointer to a template base class of the type pointed to by
23904 ARG.
23905 UNIFY_ALLOW_INTEGER:
23906 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
23907 case for more information.
23908 UNIFY_ALLOW_OUTER_LEVEL:
23909 This is the outermost level of a deduction. Used to determine validity
23910 of qualification conversions. A valid qualification conversion must
23911 have const qualified pointers leading up to the inner type which
23912 requires additional CV quals, except at the outer level, where const
23913 is not required [conv.qual]. It would be normal to set this flag in
23914 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
23915 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
23916 This is the outermost level of a deduction, and PARM can be more CV
23917 qualified at this point.
23918 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
23919 This is the outermost level of a deduction, and PARM can be less CV
23920 qualified at this point. */
23922 static int
23925 {
23927 tree targ;
23928 tree tparm;
23930 tsubst_flags_t complain = (explain_p
23931 ? tf_warning_or_error
23934 /* I don't think this will do the right thing with respect to types.
23935 But the only case I've seen it in so far has been array bounds, where
23936 signedness is the only information lost, and I think that will be
23937 okay. VIEW_CONVERT_EXPR can appear with class NTTP, thanks to
23938 finish_id_expression_1, and are also OK. */
23946 /* We can't deduce anything from this, but we might get all the
23947 template args from other function args. */
23953 /* If PARM uses template parameters, then we can't bail out here,
23954 even if ARG == PARM, since we won't record unifications for the
23955 template parameters. We might need them if we're trying to
23956 figure out which of two things is more specialized. */
23960 /* Handle init lists early, so the rest of the function can assume
23961 we're dealing with a type. */
23963 {
23964 tree elttype;
23969 /* We can only deduce from an initializer list argument if the
23970 parameter is std::initializer_list or an array; otherwise this
23971 is a non-deduced context. */
23976 else
23977 {
23979 /* Deduction is defined in terms of a single type, so just punt
23980 on the (bizarre) std::initializer_list<T...>. */
23983 }
23988 /* If ELTTYPE has no deducible template parms, skip deduction from
23990 else
23992 {
24000 {
24004 /* It should only be possible to get here for a call. */
24006 elt_strict |= maybe_adjust_types_for_deduction
24009 }
24012 explain_p);
24013 }
24017 {
24018 /* Also deduce from the length of the initializer list. */
24025 }
24027 /* If the std::initializer_list<T> deduction worked, replace the
24028 deduced A with std::initializer_list<A>. */
24030 {
24035 }
24037 }
24039 /* If parm and arg aren't the same kind of thing (template, type, or
24040 expression), fail early. */
24044 /* Immediately reject some pairs that won't unify because of
24045 cv-qualification mismatches. */
24048 /* It is the elements of the array which hold the cv quals of an array
24049 type, and the elements might be template type parms. We'll check
24050 when we recurse. */
24052 /* We check the cv-qualifiers when unifying with template type
24053 parameters below. We want to allow ARG `const T' to unify with
24054 PARM `T' for example, when computing which of two templates
24055 is more specialized, for example. */
24069 {
24073 /* In a type which contains a nested-name-specifier, template
24074 argument values cannot be deduced for template parameters used
24075 within the nested-name-specifier. */
24087 /* The PARM is not one we're trying to unify. Just check
24088 to see if it matches ARG. */
24089 {
24094 else
24096 }
24103 /* Check for mixed types and values. */
24111 {
24114 {
24115 /* First try to match ARG directly. */
24117 explain_p);
24119 {
24120 /* Otherwise, look for a suitable base of ARG, as below. */
24127 }
24128 }
24129 /* ARG must be constructed from a template class or a template
24130 template parameter. */
24135 /* Deduce arguments T, i from TT<T> or TT<i>. */
24141 /* If the template is a template template parameter, use the
24142 TEMPLATE_TEMPLATE_PARM for matching. */
24145 /* Fall through to deduce template name. */
24146 }
24150 {
24151 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
24153 /* Simple cases: Value already set, does match or doesn't. */
24158 }
24159 else
24160 {
24161 /* If PARM is `const T' and ARG is only `int', we don't have
24162 a match unless we are allowing additional qualification.
24163 If ARG is `const int' and PARM is just `T' that's OK;
24164 that binds `const int' to `T'. */
24169 /* Consider the case where ARG is `const volatile int' and
24170 PARM is `const T'. Then, T should be `volatile int'. */
24171 arg = cp_build_qualified_type
24176 /* Simple cases: Value already set, does match or doesn't. */
24182 /* Make sure that ARG is not a variable-sized array. (Note
24183 that were talking about variable-sized arrays (like
24184 `int[n]'), rather than arrays of unknown size (like
24185 `int[]').) We'll get very confused by such a type since
24186 the bound of the array is not constant, and therefore
24187 not mangleable. Besides, such types are not allowed in
24188 ISO C++, so we can do as we please here. We do allow
24189 them for 'auto' deduction, since that isn't ABI-exposed. */
24193 /* Strip typedefs as in convert_template_argument. */
24195 }
24197 /* If ARG is a parameter pack or an expansion, we cannot unify
24198 against it unless PARM is also a parameter pack. */
24203 /* If the argument deduction results is a METHOD_TYPE,
24204 then there is a problem.
24205 METHOD_TYPE doesn't map to any real C++ type the result of
24206 the deduction cannot be of that type. */
24220 {
24221 /* The PARM is not one we're trying to unify. Just check
24222 to see if it matches ARG. */
24228 }
24234 {
24238 /* We're deducing from an array bound, the type doesn't matter. */
24244 }
24246 /* [temp.deduct.type] If, in the declaration of a function template
24247 with a non-type template-parameter, the non-type
24248 template-parameter is used in an expression in the function
24249 parameter-list and, if the corresponding template-argument is
24250 deduced, the template-argument type shall match the type of the
24251 template-parameter exactly, except that a template-argument
24252 deduced from an array bound may be of any integral type.
24253 The non-type parameter might use already deduced type parameters. */
24256 /* We don't have enough levels of args to do any substitution. This
24258 else
24259 {
24265 {
24270 }
24271 }
24275 /* Template-parameter dependent expression. Just accept it for now.
24276 It will later be processed in convert_template_argument. */
24277 ;
24281 /* OK. Ignore top-level quals here because a class-type template
24285 /* Convert the ARG to the type of PARM; the deduced non-type
24286 template argument must exactly match the types of the
24287 corresponding parameter. */
24290 {
24291 /* We haven't deduced the type of this parameter yet. */
24293 /* We deduce from array bounds in try_array_deduction. */
24296 {
24297 /* Deduce it from the non-type argument. As above, ignore
24298 top-level quals here too. */
24303 /* Now check whether the type of this parameter is still
24304 dependent, and give up if so. */
24310 }
24311 else
24312 /* Try again later. */
24314 }
24315 else
24318 /* If ARG is a parameter pack or an expansion, we cannot unify
24319 against it unless PARM is also a parameter pack. */
24324 {
24327 }
24332 {
24333 /* A pointer-to-member constant can be unified only with
24334 another constant. */
24338 /* Just unify the class member. It would be useless (and possibly
24339 wrong, depending on the strict flags) to unify also
24340 PTRMEM_CST_CLASS, because we want to be sure that both parm and
24341 arg refer to the same variable, even if through different
24342 classes. For instance:
24344 struct A { int x; };
24345 struct B : A { };
24347 Unification of &A::x and &B::x must succeed. */
24350 }
24353 {
24357 /* [temp.deduct.call]
24359 A can be another pointer or pointer to member type that can
24360 be converted to the deduced A via a qualification
24361 conversion (_conv.qual_).
24363 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
24364 This will allow for additional cv-qualification of the
24365 pointed-to types if appropriate. */
24368 /* The derived-to-base conversion only persists through one
24369 level of pointers. */
24374 }
24407 /* We have already checked cv-qualification at the top of the
24408 function. */
24412 /* As far as unification is concerned, this wins. Later checks
24413 will invalidate it if necessary. */
24416 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
24417 /* Type INTEGER_CST can come from ordinary constant template args. */
24429 {
24439 /* Check for pack expansions in the parameters. */
24441 {
24443 {
24445 /* We can unify against something with a trailing
24446 parameter pack. */
24448 else
24449 /* [temp.deduct.type]/9: If the template argument list of
24450 P contains a pack expansion that is not the last
24451 template argument, the entire template argument list
24452 is a non-deduced context. */
24454 }
24455 }
24457 /* If we don't have enough arguments to satisfy the parameters
24458 (not counting the pack expression at the end), or we have
24459 too many arguments for a parameter list that doesn't end in
24460 a pack expression, we can't unify. */
24466 /* Unify all of the parameters that precede the (optional)
24467 pack expression. */
24469 {
24474 }
24477 DEDUCE_EXACT,
24480 }
24488 {
24496 }
24501 {
24505 {
24506 /* First, we try to unify the PARM and ARG directly. */
24511 {
24512 /* Fallback to the special case allowed in
24513 [temp.deduct.call]:
24515 If P is a class, and P has the form
24516 template-id, then A can be a derived class of
24517 the deduced A. Likewise, if P is a pointer to
24518 a class of the form template-id, A can be a
24519 pointer to a derived class pointed to by the
24520 deduced A. */
24526 {
24527 /* Don't give the derived diagnostic if we're
24528 already dealing with the same template. */
24529 bool same_template
24535 }
24536 }
24537 }
24541 /* Perhaps PARM is something like S<U> and ARG is S<int>.
24542 Then, we should unify `int' and `U'. */
24544 else
24545 /* There's no chance of unification succeeding. */
24550 }
24557 {
24560 tree a;
24566 /* CV qualifications for methods can never be deduced, they must
24567 match exactly. We need to check them explicitly here,
24568 because type_unification_real treats them as any other
24569 cv-qualified parameter. */
24571 && (!check_cv_quals_for_unify
24599 {
24611 }
24614 }
24617 /* Unify a pointer to member with a pointer to member function, which
24618 deduces the type of the member as a function type. */
24620 {
24621 /* Check top-level cv qualifiers */
24629 /* Determine the type of the function we are unifying against. */
24633 }
24652 /* Matched cases are handled by the ARG == PARM test above. */
24656 /* We might get a variable as a non-type template argument in parm if the
24657 corresponding parameter is type-dependent. Make any necessary
24658 adjustments based on whether arg is a reference. */
24662 {
24667 }
24668 /* Now use the normal expression code to check whether they match. */
24679 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
24680 or UNDERLYING_TYPE nodes. */
24684 /* Unification fails if we hit an error node. */
24689 {
24699 }
24700 /* FALLTHRU */
24703 /* An unresolved overload is a nondeduced context. */
24709 expr:
24710 /* We must be looking at an expression. This can happen with
24711 something like:
24713 template <int I>
24714 void foo(S<I>, S<I + 2>);
24716 or
24718 template<typename T>
24719 void foo(A<T, T{}>);
24721 This is a "non-deduced context":
24723 [deduct.type]
24725 The non-deduced contexts are:
24727 --A non-type template argument or an array bound in which
24728 a subexpression references a template parameter.
24730 In these cases, we assume deduction succeeded, but don't
24731 actually infer any unifications. */
24736 else
24738 }
24739 }
24740 #undef RECUR_AND_CHECK_FAILURE
24741 \f
24742 /* Note that DECL can be defined in this translation unit, if
24743 required. */
24745 static void
24747 {
24748 tree clone;
24752 }
24754 /* Called if RESULT is explicitly instantiated, or is a member of an
24755 explicitly instantiated class. */
24757 void
24759 {
24762 /* If this entity has already been written out, it's too late to
24763 make any modifications. */
24767 /* consteval functions are never emitted. */
24772 /* For anonymous namespace we don't need to do anything. */
24774 {
24777 }
24780 /* The TREE_PUBLIC flag for function declarations will have been
24781 set correctly by tsubst. */
24785 {
24788 }
24789 else
24790 {
24793 /* Always make artificials weak. */
24796 /* For WIN32 we also want to put explicit instantiations in
24797 linkonce sections. */
24802 /* If the function has already been instantiated, clear DECL_EXTERNAL,
24803 since start_preparsed_function wouldn't have if we had an earlier
24804 extern explicit instantiation. */
24806 }
24808 /* If EXTERN_P, then this function will not be emitted -- unless
24809 followed by an explicit instantiation, at which point its linkage
24810 will be adjusted. If !EXTERN_P, then this function will be
24811 emitted here. In neither circumstance do we want
24812 import_export_decl to adjust the linkage. */
24814 }
24816 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
24817 important template arguments. If any are missing, we check whether
24818 they're important by using error_mark_node for substituting into any
24819 args that were used for partial ordering (the ones between ARGS and END)
24820 and seeing if it bubbles up. */
24822 static bool
24824 {
24828 {
24831 }
24833 {
24837 }
24839 }
24841 /* Given two function templates PAT1 and PAT2, return:
24843 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
24844 -1 if PAT2 is more specialized than PAT1.
24845 0 if neither is more specialized.
24847 LEN indicates the number of parameters we should consider
24848 (defaulted parameters should not be considered).
24850 The 1998 std underspecified function template partial ordering, and
24851 DR214 addresses the issue. We take pairs of arguments, one from
24852 each of the templates, and deduce them against each other. One of
24853 the templates will be more specialized if all the *other*
24854 template's arguments deduce against its arguments and at least one
24855 of its arguments *does* *not* deduce against the other template's
24856 corresponding argument. Deduction is done as for class templates.
24857 The arguments used in deduction have reference and top level cv
24858 qualifiers removed. Iff both arguments were originally reference
24859 types *and* deduction succeeds in both directions, an lvalue reference
24860 wins against an rvalue reference and otherwise the template
24861 with the more cv-qualified argument wins for that pairing (if
24862 neither is more cv-qualified, they both are equal). Unlike regular
24863 deduction, after all the arguments have been deduced in this way,
24864 we do *not* verify the deduced template argument values can be
24865 substituted into non-deduced contexts.
24867 The logic can be a bit confusing here, because we look at deduce1 and
24868 targs1 to see if pat2 is at least as specialized, and vice versa; if we
24869 can find template arguments for pat1 to make arg1 look like arg2, that
24870 means that arg2 is at least as specialized as arg1. */
24872 int
24874 {
24887 /* Remove the this parameter from non-static member functions. If
24888 one is a non-static member function and the other is not a static
24889 member function, remove the first parameter from that function
24890 also. This situation occurs for operator functions where we
24891 locate both a member function (with this pointer) and non-member
24892 operator (with explicit first operand). */
24894 {
24899 }
24901 {
24904 {
24905 len--;
24907 }
24908 }
24910 /* If only one is a conversion operator, they are unordered. */
24914 /* Consider the return type for a conversion function */
24916 {
24919 len++;
24920 }
24922 processing_template_decl++;
24928 /* Stop when an ellipsis is seen. */
24930 {
24941 {
24942 /* When both arguments are pack expansions, we need only
24943 unify the patterns themselves. */
24947 /* This is the last comparison we need to do. */
24949 }
24952 {
24956 }
24959 {
24963 }
24969 {
24975 /* Setup the parameter vector, which contains only ARG1. */
24978 /* Setup the argument vector, which contains the remaining
24979 arguments. */
24988 /* We cannot deduce in the other direction, because ARG1 is
24989 a pack expansion but ARG2 is not. */
24991 }
24993 {
24999 /* Setup the parameter vector, which contains only ARG1. */
25002 /* Setup the argument vector, which contains the remaining
25003 arguments. */
25012 /* We cannot deduce in the other direction, because ARG2 is
25013 a pack expansion but ARG1 is not.*/
25015 }
25017 else
25018 {
25019 /* The normal case, where neither argument is a pack
25020 expansion. */
25027 }
25029 /* If we couldn't deduce arguments for tparms1 to make arg1 match
25030 arg2, then arg2 is not as specialized as arg1. */
25036 /* "If, for a given type, deduction succeeds in both directions
25037 (i.e., the types are identical after the transformations above)
25038 and both P and A were reference types (before being replaced with
25039 the type referred to above):
25040 - if the type from the argument template was an lvalue reference and
25041 the type from the parameter template was not, the argument type is
25042 considered to be more specialized than the other; otherwise,
25043 - if the type from the argument template is more cv-qualified
25044 than the type from the parameter template (as described above),
25045 the argument type is considered to be more specialized than the other;
25046 otherwise,
25047 - neither type is more specialized than the other." */
25050 {
25052 {
25055 else
25057 }
25059 {
25064 }
25065 }
25068 /* We've failed to deduce something in either direction.
25069 These must be unordered. */
25074 /* We have already processed all of the arguments in our
25075 handing of the pack expansion type. */
25080 }
25082 /* "In most cases, all template parameters must have values in order for
25083 deduction to succeed, but for partial ordering purposes a template
25084 parameter may remain without a value provided it is not used in the
25085 types being used for partial ordering."
25087 Thus, if we are missing any of the targs1 we need to substitute into
25088 origs1, then pat2 is not as specialized as pat1. This can happen when
25089 there is a nondeduced context. */
25095 processing_template_decl--;
25097 /* If both deductions succeed, the partial ordering selects the more
25098 constrained template. */
25099 /* P2113: If the corresponding template-parameters of the
25100 template-parameter-lists are not equivalent ([temp.over.link]) or if
25101 the function parameters that positionally correspond between the two
25102 templates are not of the same type, neither template is more
25103 specialized than the other. */
25108 {
25114 }
25116 /* All things being equal, if the next argument is a pack expansion
25117 for one function but not for the other, prefer the
25118 non-variadic function. FIXME this is bogus; see c++/41958. */
25122 {
25125 }
25131 else
25133 }
25135 /* Determine which of two partial specializations of TMPL is more
25136 specialized.
25138 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
25139 to the first partial specialization. The TREE_PURPOSE is the
25140 innermost set of template parameters for the partial
25141 specialization. PAT2 is similar, but for the second template.
25143 Return 1 if the first partial specialization is more specialized;
25144 -1 if the second is more specialized; 0 if neither is more
25145 specialized.
25147 See [temp.class.order] for information about determining which of
25148 two templates is more specialized. */
25150 static int
25152 {
25153 tree targs;
25162 /* Just like what happens for functions, if we are ordering between
25163 different template specializations, we may encounter dependent
25164 types in the arguments, and we need our dependency check functions
25165 to behave correctly. */
25169 {
25172 }
25176 {
25179 }
25182 /* If both deductions succeed, the partial ordering selects the more
25183 constrained template. */
25187 /* In the case of a tie where at least one of the templates
25188 has a parameter pack at the end, the template with the most
25189 non-packed parameters wins. */
25191 && any_deductions
25194 {
25200 /* We don't count the pack expansion at the end. */
25210 }
25213 }
25215 /* Return the template arguments that will produce the function signature
25216 DECL from the function template FN, with the explicit template
25217 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
25218 also match. Return NULL_TREE if no satisfactory arguments could be
25219 found. */
25221 static tree
25223 {
25227 tree decl_arg_types;
25230 tree arg;
25234 /* Never do unification on the 'this' parameter. */
25256 }
25258 /* Return the innermost template arguments that, when applied to a partial
25259 specialization SPEC_TMPL of TMPL, yield the ARGS.
25261 For example, suppose we have:
25263 template <class T, class U> struct S {};
25264 template <class T> struct S<T*, int> {};
25266 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
25267 partial specialization and the ARGS will be {double*, int}. The resulting
25268 vector will be {double}, indicating that `T' is bound to `double'. */
25270 static tree
25272 {
25274 tree spec_args
25277 tree deduced_args;
25278 tree innermost_deduced_args;
25282 {
25286 innermost_deduced_args);
25287 }
25288 else
25292 again:
25301 {
25303 {
25309 }
25311 }
25314 {
25317 }
25319 /* Verify that nondeduced template arguments agree with the type
25320 obtained from argument deduction.
25322 For example:
25324 struct A { typedef int X; };
25325 template <class T, class U> struct C {};
25326 template <class T> struct C<T, typename T::X> {};
25328 Then with the instantiation `C<A, int>', we can deduce that
25329 `T' is `A' but unify () does not check whether `typename T::X'
25330 is `int'. */
25341 /* We only need to check the innermost arguments; the other
25342 arguments will always agree. */
25347 /* Now that we have bindings for all of the template arguments,
25348 ensure that the arguments deduced for the template template
25349 parameters have compatible template parameter lists. See the use
25350 of template_template_parm_bindings_ok_p in fn_type_unification
25351 for more information. */
25356 }
25358 // Compare two function templates T1 and T2 by deducing bindings
25359 // from one against the other. If both deductions succeed, compare
25360 // constraints to see which is more constrained.
25361 static int
25363 {
25368 {
25371 }
25374 {
25377 }
25379 // If both deductions succeed, then one may be more constrained.
25384 }
25386 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
25387 Return the TREE_LIST node with the most specialized template, if
25388 any. If there is no most specialized template, the error_mark_node
25389 is returned.
25391 Note that this function does not look at, or modify, the
25392 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
25393 returned is one of the elements of INSTANTIATIONS, callers may
25394 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
25395 and retrieve it from the value returned. */
25397 tree
25399 {
25406 {
25412 {
25413 /* Equally specialized, move to next function. If there
25414 is no next function, nothing's most specialized. */
25419 }
25420 }
25423 /* Now verify that champ is better than everything earlier in the
25424 instantiation list. */
25427 {
25430 }
25431 }
25433 processing_template_decl--;
25439 }
25441 /* If DECL is a specialization of some template, return the most
25442 general such template. Otherwise, returns NULL_TREE.
25444 For example, given:
25446 template <class T> struct S { template <class U> void f(U); };
25448 if TMPL is `template <class U> void S<int>::f(U)' this will return
25449 the full template. This function will not trace past partial
25450 specializations, however. For example, given in addition:
25452 template <class T> struct S<T*> { template <class U> void f(U); };
25454 if TMPL is `template <class U> void S<int*>::f(U)' this will return
25455 `template <class T> template <class U> S<T*>::f(U)'. */
25457 tree
25459 {
25461 {
25464 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
25465 template friend, or a FIELD_DECL for a capture pack. */
25468 }
25470 /* Look for more and more general templates. */
25472 {
25473 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
25474 (See cp-tree.h for details.) */
25483 /* Stop if we run into an explicitly specialized class template. */
25490 }
25493 }
25495 /* Return the most specialized of the template partial specializations
25496 which can produce TARGET, a specialization of some class or variable
25497 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
25498 a TEMPLATE_DECL node corresponding to the partial specialization, while
25499 the TREE_PURPOSE is the set of template arguments that must be
25500 substituted into the template pattern in order to generate TARGET.
25502 If the choice of partial specialization is ambiguous, a diagnostic
25503 is issued, and the error_mark_node is returned. If there are no
25504 partial specializations matching TARGET, then NULL_TREE is
25505 returned, indicating that the primary template should be used. */
25507 tree
25509 {
25511 tree t;
25512 tree champ;
25518 tree decl;
25520 {
25525 }
25527 {
25531 }
25533 {
25538 }
25539 else
25547 /* For determining which partial specialization to use, only the
25548 innermost args are interesting. */
25550 {
25553 }
25555 /* The caller hasn't called push_to_top_level yet, but we need
25556 get_partial_spec_bindings to be done in non-template context so that we'll
25557 fully resolve everything. */
25558 processing_template_decl_sentinel ptds;
25561 {
25564 tree spec_tmpl;
25566 {
25567 /* Substitute in the template args from the enclosing class. */
25573 }
25574 else
25579 {
25583 /* Keep the candidate only if the constraints are satisfied,
25584 or if we're not compiling with concepts. */
25587 {
25590 }
25591 }
25592 }
25602 {
25605 ;
25606 else
25607 {
25609 {
25612 {
25615 }
25616 }
25618 }
25619 }
25623 {
25626 {
25629 }
25630 }
25633 {
25640 else
25644 {
25649 }
25652 }
25655 }
25657 /* Explicitly instantiate DECL. */
25659 void
25661 {
25666 /* An error occurred, for which grokdeclarator has already issued
25667 an appropriate message. */
25670 {
25673 }
25675 {
25678 else
25681 }
25687 {
25688 /* There is an asymmetry here in the way VAR_DECLs and
25689 FUNCTION_DECLs are handled by grokdeclarator. In the case of
25690 the latter, the DECL we get back will be marked as a
25691 template instantiation, and the appropriate
25692 DECL_TEMPLATE_INFO will be set up. This does not happen for
25693 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
25694 should handle VAR_DECLs as it currently handles
25695 FUNCTION_DECLs. */
25697 {
25700 }
25703 {
25706 }
25708 {
25713 }
25714 }
25716 {
25719 }
25720 else
25723 /* Check for various error cases. Note that if the explicit
25724 instantiation is valid the RESULT will currently be marked as an
25725 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
25726 until we get here. */
25729 {
25730 /* DR 259 [temp.spec].
25732 Both an explicit instantiation and a declaration of an explicit
25733 specialization shall not appear in a program unless the explicit
25734 instantiation follows a declaration of the explicit specialization.
25736 For a given set of template parameters, if an explicit
25737 instantiation of a template appears after a declaration of an
25738 explicit specialization for that template, the explicit
25739 instantiation has no effect. */
25741 }
25743 {
25744 /* [temp.spec]
25746 No program shall explicitly instantiate any template more
25747 than once.
25749 We check DECL_NOT_REALLY_EXTERN so as not to complain when
25750 the first instantiation was `extern' and the second is not,
25751 and EXTERN_P for the opposite case. */
25754 /* If an "extern" explicit instantiation follows an ordinary
25755 explicit instantiation, the template is instantiated. */
25758 }
25760 {
25763 }
25765 {
25768 }
25771 ;
25773 {
25776 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
25779 }
25780 else
25788 }
25790 static void
25792 {
25798 {
25801 }
25802 }
25804 /* Perform an explicit instantiation of template class T. STORAGE, if
25805 non-null, is the RID for extern, inline or static. COMPLAIN is
25806 nonzero if this is called from the parser, zero if called recursively,
25807 since the standard is unclear (as detailed below). */
25809 void
25811 {
25813 {
25817 else
25820 }
25825 {
25828 t);
25830 }
25832 /* At most one of these will be true. */
25838 {
25840 {
25843 "ISO C++ 1998 forbids the use of %<extern%> on "
25845 }
25846 else
25848 "ISO C++ forbids the use of %qE"
25857 else
25859 storage);
25860 }
25863 /* DR 259 [temp.spec].
25865 Both an explicit instantiation and a declaration of an explicit
25866 specialization shall not appear in a program unless the
25867 explicit instantiation follows a declaration of the explicit
25868 specialization.
25870 For a given set of template parameters, if an explicit
25871 instantiation of a template appears after a declaration of an
25872 explicit specialization for that template, the explicit
25873 instantiation has no effect. */
25877 {
25878 /* We've already instantiated the template. */
25880 /* [temp.spec]
25882 No program shall explicitly instantiate any template more
25883 than once.
25885 If EXTERN_P then this is ok. */
25891 }
25899 /* In contrast to implicit instantiation, where only the
25900 declarations, and not the definitions, of members are
25901 instantiated, we have here:
25903 [temp.explicit]
25905 An explicit instantiation that names a class template
25906 specialization is also an explicit instantiation of the same
25907 kind (declaration or definition) of each of its members (not
25908 including members inherited from base classes and members
25909 that are templates) that has not been previously explicitly
25910 specialized in the translation unit containing the explicit
25911 instantiation, provided that the associated constraints, if
25912 any, of that member are satisfied by the template arguments
25913 of the explicit instantiation. */
25917 && !static_p
25921 {
25926 }
25928 {
25934 }
25935 }
25937 /* Given a function DECL, which is a specialization of TMPL, modify
25938 DECL to be a re-instantiation of TMPL with the same template
25939 arguments. TMPL should be the template into which tsubst'ing
25940 should occur for DECL, not the most general template.
25942 One reason for doing this is a scenario like this:
25944 template <class T>
25945 void f(const T&, int i);
25947 void g() { f(3, 7); }
25949 template <class T>
25950 void f(const T& t, const int i) { }
25952 Note that when the template is first instantiated, with
25953 instantiate_template, the resulting DECL will have no name for the
25954 first parameter, and the wrong type for the second. So, when we go
25955 to instantiate the DECL, we regenerate it. */
25957 static void
25959 {
25960 /* The arguments used to instantiate DECL, from the most general
25961 template. */
25962 tree code_pattern;
25966 /* Make sure that we can see identifiers, and compute access
25967 correctly. */
25971 {
25972 tree specs;
25976 /* Use the source location of the definition. */
25984 /* Instantiate a dynamic exception-specification. noexcept will be
25985 handled below. */
25988 {
25994 specs);
25995 }
25997 /* Merge parameter declarations. */
26001 {
26008 }
26010 /* Merge additional specifiers from the CODE_PATTERN. */
26016 }
26018 {
26027 }
26028 else
26032 }
26034 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
26035 substituted to get DECL. */
26037 tree
26039 {
26042 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
26043 for the instantiation. This is not always the most general
26044 template. Consider, for example:
26046 template <class T>
26047 struct S { template <class U> void f();
26048 template <> void f<int>(); };
26050 and an instantiation of S<double>::f<int>. We want TD to be the
26051 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
26053 more general template. */
26055 /* We must also deal with friend templates. Given:
26057 template <class T> struct S {
26058 template <class U> friend void f() {};
26059 };
26061 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
26062 so far as the language is concerned, but that's still
26063 where we get the pattern for the instantiation from. On
26064 other hand, if the definition comes outside the class, say:
26066 template <class T> struct S {
26067 template <class U> friend void f();
26068 };
26069 template <class U> friend void f() {}
26071 we don't need to look any further. That's what the check for
26072 DECL_INITIAL is for. */
26076 {
26077 /* The present template, TD, should not be a definition. If it
26078 were a definition, we should be using it! Note that we
26079 cannot restructure the loop to just keep going until we find
26080 a template with a definition, since that might go too far if
26081 a specialization was declared, but not defined. */
26083 /* Fetch the more general template. */
26085 }
26088 }
26090 /* Returns true if we need to instantiate this template instance even if we
26091 know we aren't going to emit it. */
26093 bool
26095 {
26096 /* We always instantiate inline functions so that we can inline them. An
26097 explicit instantiation declaration prohibits implicit instantiation of
26098 non-inline functions. With high levels of optimization, we would
26099 normally inline non-inline functions -- but we're not allowed to do
26100 that for "extern template" functions. Therefore, we check
26101 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
26105 /* And we need to instantiate static data members so that
26106 their initializers are available in integral constant
26107 expressions. */
26110 }
26112 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
26113 instantiate it now, modifying TREE_TYPE (fn). Returns false on
26114 error, true otherwise. */
26116 bool
26118 {
26122 /* Don't instantiate a noexcept-specification from template context. */
26132 {
26134 /* We're in start_preparsed_function, keep going. */
26141 }
26152 /* For a member friend template we can get a TEMPLATE_DECL. Let's use
26153 its FUNCTION_DECL for the rest of this function -- push_access_scope
26154 doesn't accept TEMPLATE_DECLs. */
26156 {
26159 }
26162 {
26167 }
26169 {
26173 {
26176 /* This might have failed because of an unparsed DMI, so
26177 let's try again later. */
26179 }
26181 {
26182 /* If hash_set::add returns true, the element was already there. */
26187 fn);
26189 }
26191 {
26199 {
26200 /* If needed, set current_class_ptr for the benefit of
26201 tsubst_copy/PARM_DECL. */
26206 }
26208 /* If this function is represented by a TEMPLATE_DECL, then
26209 the deferred noexcept-specification might still contain
26210 dependent types, even after substitution. And we need the
26211 dependency check functions to work in build_noexcept_spec. */
26215 /* Do deferred instantiation of the noexcept-specifier. */
26222 /* Build up the noexcept-specification. */
26232 }
26233 else
26238 }
26241 {
26242 /* This failed with a hard error, so let's go with false. */
26245 }
26252 }
26254 /* We're starting to process the function INST, an instantiation of PATTERN;
26255 add their parameters to local_specializations. */
26257 static void
26259 {
26263 {
26267 }
26269 {
26271 {
26274 }
26275 else
26276 {
26277 /* Register the (value) argument pack as a specialization of
26278 TMPL_PARM, then move on. */
26281 }
26282 }
26284 }
26286 /* Instantiate the body of D using PATTERN with ARGS. We have
26287 already determined PATTERN is the correct template to use.
26288 NESTED_P is true if this is a nested function, in which case
26289 PATTERN will be a FUNCTION_DECL not a TEMPLATE_DECL. */
26291 static void
26293 {
26298 {
26301 }
26302 else
26303 /* Only OMP reductions are nested. */
26310 bool push_to_top
26311 = !(current_function_decl
26317 else
26318 {
26323 }
26326 {
26327 /* The variable might be a lambda's extra scope, and that
26328 lambda's visibility depends on D's. */
26331 }
26333 /* Mark D as instantiated so that recursive calls to
26334 instantiate_decl do not try to instantiate it again. */
26338 /* Regenerate the declaration in case the template has been modified
26339 by a subsequent redeclaration. */
26342 /* We already set the file and line above. Reset them now in case
26343 they changed as a result of calling regenerate_decl_from_template. */
26347 {
26348 /* Clear out DECL_RTL; whatever was there before may not be right
26349 since we've reset the type of the declaration. */
26353 /* The initializer is placed in DECL_INITIAL by
26354 regenerate_decl_from_template so we don't need to
26355 push/pop_access_scope again here. Pull it out so that
26356 cp_finish_decl can process it. */
26362 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
26363 initializer. That function will defer actual emission until
26364 we have a chance to determine linkage. */
26367 /* Enter the scope of D so that access-checking works correctly. */
26377 }
26381 {
26382 /* Set up the list of local specializations. */
26386 /* Set up context. */
26389 else
26390 {
26394 }
26396 /* Create substitution entries for the parameters. */
26399 /* Substitute into the body of the function. */
26403 else
26404 {
26409 /* Set the current input_location to the end of the function
26410 so that finish_function knows where we are. */
26411 input_location
26414 /* Remember if we saw an infinite loop in the template. */
26415 current_function_infinite_loop
26417 }
26419 /* Finish the function. */
26422 else
26423 {
26426 }
26430 }
26432 /* We're not deferring instantiation any more. */
26438 else
26443 }
26445 /* Produce the definition of D, a _DECL generated from a template. If
26446 DEFER_OK is true, then we don't have to actually do the
26447 instantiation now; we just have to do it sometime. Normally it is
26448 an error if this is an explicit instantiation but D is undefined.
26449 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
26450 instantiated class template. */
26452 tree
26454 {
26456 tree gen_args;
26457 tree args;
26458 tree td;
26459 tree code_pattern;
26460 tree spec;
26461 tree gen_tmpl;
26469 /* This function should only be used to instantiate templates for
26470 functions and static member variables. */
26473 /* A concept is never instantiated. */
26479 /* We may have a pending instantiation of D itself. */
26482 /* Variables are never deferred; if instantiation is required, they
26483 are instantiated right away. That allows for better code in the
26484 case that an expression refers to the value of the variable --
26485 if the variable has a constant value the referring expression can
26486 take advantage of that fact. */
26490 /* Don't instantiate cloned functions. Instead, instantiate the
26491 functions they cloned. */
26500 /* D has already been instantiated or explicitly specialized, so
26501 there's nothing for us to do here.
26503 It might seem reasonable to check whether or not D is an explicit
26504 instantiation, and, if so, stop here. But when an explicit
26505 instantiation is deferred until the end of the compilation,
26506 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
26507 the instantiation. */
26510 /* Check to see whether we know that this template will be
26511 instantiated in some other file, as with "extern template"
26512 extension. */
26515 /* In general, we do not instantiate such templates. */
26522 /* We should already have the extra args. */
26526 /* And what's in the hash table should match D. */
26528 == d
26531 /* This needs to happen before any tsubsting. */
26537 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
26538 for the instantiation. */
26543 {
26544 /* Look up an explicit specialization, if any. */
26547 {
26550 }
26551 }
26555 /* We should never be trying to instantiate a member of a class
26556 template or partial specialization. */
26561 /* In the case of a friend template whose definition is provided
26562 outside the class, we may have too many arguments. Drop the
26563 ones we don't need. The same is true for specializations. */
26564 args = get_innermost_template_args
26568 {
26574 }
26575 else
26576 {
26580 else
26582 }
26584 /* We may be in the middle of deferred access check. Disable it now. */
26587 /* Unless an explicit instantiation directive has already determined
26588 the linkage of D, remember that a definition is available for
26589 this entity. */
26599 /* If D is a member of an explicitly instantiated class template,
26600 and no definition is available, treat it like an implicit
26601 instantiation. */
26604 {
26605 /* Leave linkage flags alone on instantiations with anonymous
26606 visibility. */
26608 {
26611 }
26613 }
26615 /* Defer all other templates, unless we have been explicitly
26616 forbidden from doing so. */
26618 template. */
26619 ! pattern_defined
26620 /* If it's OK to postpone instantiation, do so. */
26621 || defer_ok
26622 /* If this is a static data member that will be defined
26623 elsewhere, we don't want to instantiate the entire data
26624 member, but we do want to instantiate the initializer so that
26625 we can substitute that elsewhere. */
26627 /* Handle here a deleted function too, avoid generating
26628 its body (c++/61080). */
26630 {
26631 /* The definition of the static data member is now required so
26632 we must substitute the initializer. */
26636 {
26637 tree ns;
26638 tree init;
26647 args,
26650 /* If instantiating the initializer involved instantiating this
26651 again, don't call cp_finish_decl twice. */
26653 {
26654 /* Make sure the initializer is still constant, in case of
26655 circular dependency (template/instantiate6.C). */
26656 const_init
26660 }
26664 }
26666 /* We restore the source position here because it's used by
26667 add_pending_template. */
26673 /* [temp.explicit]
26675 The definition of a non-exported function template, a
26676 non-exported member function template, or a non-exported
26677 member function or static data member of a class template
26678 shall be present in every translation unit in which it is
26679 explicitly instantiated. */
26683 /* If we're in unevaluated context, we just wanted to get the
26684 constant value; this isn't an odr use, so don't queue
26685 a full instantiation. */
26687 /* ??? Historically, we have instantiated inline functions, even
26688 when marked as "extern template". */
26691 }
26692 else
26693 {
26698 }
26707 }
26709 /* Run through the list of templates that we wish we could
26710 instantiate, and instantiate any we can. RETRIES is the
26711 number of times we retry pending template instantiation. */
26713 void
26715 {
26719 /* Instantiating templates may trigger vtable generation. This in turn
26720 may require further template instantiations. We place a limit here
26721 to avoid infinite loop. */
26723 {
26727 "template instantiation depth exceeds maximum of %d"
26728 " instantiating %q+D, possibly from virtual table generation"
26732 /* Pretend that we defined it. */
26735 }
26737 do
26738 {
26743 {
26748 {
26750 {
26765 }
26768 }
26769 else
26770 {
26773 {
26774 instantiation
26780 }
26784 }
26787 {
26788 /* If INSTANTIATION has been instantiated, then we don't
26789 need to consider it again in the future. */
26794 }
26795 else
26796 {
26799 }
26802 }
26804 }
26808 }
26810 /* Substitute ARGVEC into T, which is a list of initializers for
26811 either base class or a non-static data member. The TREE_PURPOSEs
26812 are DECLs, and the TREE_VALUEs are the initializer values. Used by
26813 instantiate_decl. */
26815 static tree
26817 {
26822 {
26823 tree decl;
26824 tree init;
26830 {
26831 tree expr;
26832 tree arg;
26834 /* Expand the base class expansion type into separate base
26835 classes. */
26837 tf_warning_or_error,
26838 NULL_TREE);
26842 /* We'll be building separate TREE_LISTs of arguments for
26843 each base. */
26849 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
26850 expand each argument in the TREE_VALUE of t. */
26857 /* VOID_TYPE_NODE is used to indicate
26858 value-initialization. */
26859 {
26862 }
26863 else
26864 {
26865 /* Substitute parameter packs into each argument in the
26866 TREE_LIST. */
26869 {
26870 tree expanded_exprs;
26872 /* Expand the argument. */
26873 tree value;
26876 else
26877 {
26880 }
26881 expanded_exprs
26883 tf_warning_or_error,
26884 NULL_TREE);
26888 /* Prepend each of the expanded expressions to the
26889 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
26897 else
26902 }
26905 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
26906 since we built them backwards. */
26908 {
26911 }
26912 }
26913 }
26916 {
26918 {
26922 }
26923 else
26924 {
26925 tree tmp;
26940 /* If we had an initializer but it instantiated to nothing,
26941 value-initialize the object. This will only occur when
26942 the initializer was a pack expansion where the parameter
26943 packs used in that expansion were of length zero. */
26946 }
26950 {
26952 decl);
26954 }
26955 /* Look for a target constructor. */
26959 {
26962 {
26966 }
26968 }
26971 {
26973 /* Carry over the dummy TREE_TYPE node containing the source
26974 location. */
26978 }
26979 }
26980 }
26982 }
26984 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
26985 is the instantiation (which should have been created with
26986 start_enum) and ARGS are the template arguments to use. */
26988 static void
26990 {
26991 tree e;
26997 {
26998 tree value;
27001 /* Note that in a template enum, the TREE_VALUE is the
27002 CONST_DECL, not the corresponding INTEGER_CST. */
27007 /* Give this enumeration constant the correct access. */
27010 /* Actually build the enumerator itself. Here we're assuming that
27011 enumerators can't have dependent attributes. */
27015 /* Attribute deprecated without an argument isn't sticky: it'll
27016 melt into a tree flag, so we need to propagate the flag here,
27017 since we just created a new enumerator. */
27020 }
27032 }
27034 /* DECL is a FUNCTION_DECL that is a template specialization. Return
27035 its type -- but without substituting the innermost set of template
27036 arguments. So, innermost set of template parameters will appear in
27037 the type. */
27039 tree
27041 {
27042 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
27044 }
27046 /* Return truthvalue if we're processing a template different from
27047 the last one involved in diagnostics. */
27048 bool
27050 {
27052 }
27054 /* Remember current template involved in diagnostics. */
27055 void
27057 {
27059 }
27063 {
27065 }
27067 /* Return TRUE if current_function_decl is being instantiated, false
27068 otherwise. */
27070 bool
27072 {
27076 }
27078 /* [temp.param] Check that template non-type parm TYPE is of an allowable
27079 type. Return false for ok, true for disallowed. Issue error and
27080 inform messages under control of COMPLAIN. */
27082 static bool
27084 {
27095 {
27097 {
27102 }
27104 }
27109 /* Fall through; before C++11 alias templates, a bound ttp
27112 /* Any other wildcard type not already handled above is allowed. */
27119 {
27127 {
27128 auto_diagnostic_group d;
27132 }
27134 }
27136 {
27141 }
27144 {
27147 else
27149 type);
27150 }
27152 }
27154 /* Returns true iff the noexcept-specifier for TYPE is value-dependent. */
27156 static bool
27158 {
27161 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
27162 affect overload resolution and treating it as dependent breaks
27163 things. Same for an unparsed noexcept expression. */
27170 }
27172 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
27173 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
27175 static bool
27177 {
27178 tree scope;
27180 /* [temp.dep.type]
27182 A type is dependent if it is:
27184 -- a template parameter. Template template parameters are types
27185 for us (since TYPE_P holds true for them) so we handle
27186 them here. */
27190 /* -- a qualified-id with a nested-name-specifier which contains a
27191 class-name that names a dependent type or whose unqualified-id
27192 names a dependent type. */
27196 /* An alias template specialization can be dependent even if the
27197 resulting type is not. */
27201 /* -- a cv-qualified type where the cv-unqualified type is
27202 dependent.
27203 No code is necessary for this bullet; the code below handles
27204 cv-qualified types, and we don't want to strip aliases with
27205 TYPE_MAIN_VARIANT because of DR 1558. */
27206 /* -- a compound type constructed from any dependent type. */
27214 {
27215 tree arg_type;
27220 arg_type;
27226 /* A value-dependent noexcept-specifier makes the type dependent. */
27229 }
27230 /* -- an array type constructed from any dependent type or whose
27231 size is specified by a constant expression that is
27232 value-dependent.
27234 We checked for type- and value-dependence of the bounds in
27235 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
27237 {
27242 }
27244 /* -- a template-id in which either the template name is a template
27245 parameter ... */
27248 /* ... or any of the template arguments is a dependent type or
27249 an expression that is type-dependent or value-dependent. */
27251 && (any_dependent_template_arguments_p
27255 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
27256 dependent; if the argument of the `typeof' expression is not
27257 type-dependent, then it should already been have resolved. */
27263 /* A template argument pack is dependent if any of its packed
27264 arguments are. */
27266 {
27271 }
27273 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
27274 be template parameters. */
27284 /* The standard does not specifically mention types that are local
27285 to template functions or local classes, but they should be
27286 considered dependent too. For example:
27288 template <int I> void f() {
27289 enum E { a = I };
27290 S<sizeof (E)> s;
27291 }
27293 The size of `E' cannot be known until the value of `I' has been
27294 determined. Therefore, `E' must be considered dependent. */
27298 /* Don't use type_dependent_expression_p here, as it can lead
27299 to infinite recursion trying to determine whether a lambda
27300 nested in a lambda is dependent (c++/47687). */
27304 && (any_dependent_template_arguments_p
27308 /* Other types are non-dependent. */
27310 }
27312 /* Returns TRUE if TYPE is dependent, in the sense of
27313 [temp.dep.type]. Note that a NULL type is considered dependent. */
27315 bool
27317 {
27318 /* If there are no template parameters in scope, then there can't be
27319 any dependent types. */
27321 {
27322 /* If we are not processing a template, then nobody should be
27323 providing us with a dependent type. */
27327 }
27329 /* If the type is NULL, we have not computed a type for the entity
27330 in question; in that case, the type is dependent. */
27334 /* Erroneous types can be considered non-dependent. */
27338 /* If we have not already computed the appropriate value for TYPE,
27339 do so now. */
27341 {
27344 }
27347 }
27349 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
27350 lookup. In other words, a dependent type that is not the current
27351 instantiation. */
27353 bool
27355 {
27358 }
27360 /* True if we might find more declarations in SCOPE during instantiation than
27361 we can when parsing the template. */
27363 bool
27365 {
27367 }
27369 /* T is a SCOPE_REF. Return whether it represents a non-static member of
27370 an unknown base of 'this' (and is therefore instantiation-dependent). */
27372 static bool
27374 {
27391 }
27393 /* T is a SCOPE_REF; return whether we need to consider it
27394 instantiation-dependent so that we can check access at instantiation
27395 time even though we know which member it resolves to. */
27397 static bool
27399 {
27407 else
27409 }
27411 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
27412 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
27413 expression. */
27415 /* Note that this predicate is not appropriate for general expressions;
27416 only constant expressions (that satisfy potential_constant_expression)
27417 can be tested for value dependence. */
27419 bool
27421 {
27425 /* A type-dependent expression is also value-dependent. */
27430 {
27432 /* A dependent member function of the current instantiation. */
27436 /* A dependent member function of the current instantiation. */
27443 /* A name that has not been looked up -- must be dependent. */
27447 /* A non-type template parm. */
27451 /* A non-type template parm. */
27457 /* A constant with literal type and is initialized
27458 with an expression that is value-dependent. */
27460 /* FIXME cp_finish_decl doesn't fold reference initializers. */
27464 {
27467 /* __PRETTY_FUNCTION__ inside a template function is dependent
27468 on the name of the function. */
27470 /* It might be used in a template, but not a template
27471 function, in which case its DECL_VALUE_EXPR will be
27472 "top level". */
27475 }
27484 /* These expressions are value-dependent if the type to which
27485 the cast occurs is dependent or the expression being casted
27486 is value-dependent. */
27487 {
27493 /* A functional cast has a list of operands. */
27496 {
27497 /* If there are no operands, it must be an expression such
27498 as "int()". This should not happen for aggregate types
27499 because it would form non-constant expressions. */
27504 }
27514 }
27519 /* FALLTHRU */
27522 /* A `sizeof' expression is value-dependent if the operand is
27523 type-dependent or is a pack expansion. */
27532 /* An 'encode' expression is value-dependent if the operand is
27533 type-dependent. */
27542 /* All instantiation-dependent expressions should also be considered
27543 value-dependent. */
27551 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
27552 is value-dependent. */
27559 {
27576 }
27587 {
27591 }
27594 /* Treat all requires-expressions as value-dependent so
27595 we don't try to fold them. */
27602 {
27609 {
27611 /* In a call to a constexpr member function, look through the
27612 implicit ADDR_EXPR on the object argument so that it doesn't
27613 cause the call to be considered value-dependent. We also
27614 look through it in potential_constant_expression. */
27621 }
27623 }
27630 {
27632 tree val;
27639 }
27642 /* Treat a GNU statement expression as dependent to avoid crashing
27643 under instantiate_non_dependent_expr; it can't be constant. */
27647 /* A constant expression is value-dependent if any subexpression is
27648 value-dependent. */
27650 {
27657 {
27661 {
27664 /* In some cases, some of the operands may be missing.
27665 (For example, in the case of PREDECREMENT_EXPR, the
27666 amount to increment by may be missing.) That doesn't
27667 make the expression dependent. */
27670 }
27671 }
27675 }
27677 }
27679 /* The expression is not value-dependent. */
27681 }
27683 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
27684 [temp.dep.expr]. Note that an expression with no type is
27685 considered dependent. Other parts of the compiler arrange for an
27686 expression with type-dependent subexpressions to have no type, so
27687 this function doesn't have to be fully recursive. */
27689 bool
27691 {
27702 /* An unresolved name is always dependent. */
27708 /* A lambda-expression in template context is dependent. dependent_type_p is
27709 true for a lambda in the scope of a class or function template, but that
27710 doesn't cover all template contexts, like a default template argument. */
27714 /* A fold expression is type-dependent. */
27721 /* Some expression forms are never type-dependent. */
27734 /* The types of these expressions depends only on the type to which
27735 the cast occurs. */
27744 /* The types of these expressions depends only on the type created
27745 by the expression. */
27748 {
27749 /* For NEW_EXPR tree nodes created inside a template, either
27750 the object type itself or a TREE_LIST may appear as the
27751 operand 1. */
27754 /* This is an array type. We need to check array dimensions
27755 as well. */
27757 || value_dependent_expression_p
27759 /* Array type whose dimension has to be deduced. */
27763 else
27765 }
27768 {
27772 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
27773 contains an identifier associated by name lookup with one or more
27774 declarations declared with a dependent type, or...a
27775 nested-name-specifier or qualified-id that names a member of an
27776 unknown specialization. */
27779 }
27789 {
27794 }
27796 /* A static data member of the current instantiation with incomplete
27797 array type is type-dependent, as the definition and specializations
27798 can have different bounds. */
27805 /* An array of unknown bound depending on a variadic parameter, eg:
27807 template<typename... Args>
27808 void foo (Args... args)
27809 {
27810 int arr[] = { args... };
27811 }
27813 template<int... vals>
27814 void bar ()
27815 {
27816 int arr[] = { vals... };
27817 }
27819 If the array has no length and has an initializer, it must be that
27820 we couldn't determine its length in cp_complete_array_type because
27821 it is dependent. */
27829 /* A function or variable template-id is type-dependent if it has any
27830 dependent template arguments. */
27834 {
27835 /* Consider the innermost template arguments, since those are the ones
27836 that come from the template-id; the template arguments for the
27837 enclosing class do not make it type-dependent unless they are used in
27838 the type of the decl. */
27840 && (any_dependent_template_arguments_p
27843 }
27845 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
27846 type-dependent. Checking this is important for functions with auto return
27847 type, which looks like a dependent type. */
27856 {
27860 }
27862 /* Always dependent, on the number of arguments if nothing else. */
27867 {
27872 {
27878 }
27879 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
27883 /* CO_AWAIT/YIELD_EXPR with unknown type is always dependent. */
27889 {
27894 }
27897 {
27904 }
27913 }
27915 /* The type of a non-type template parm declared with a placeholder type
27916 depends on the corresponding template argument, even though
27917 placeholders are not normally considered dependent. */
27924 /* Dependent type attributes might not have made it from the decl to
27925 the type yet. */
27931 }
27933 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
27934 type-dependent if the expression refers to a member of the current
27935 instantiation and the type of the referenced member is dependent, or the
27936 class member access expression refers to a member of an unknown
27937 specialization.
27939 This function returns true if the OBJECT in such a class member access
27940 expression is of an unknown specialization. */
27942 bool
27944 {
27945 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
27946 dependent. */
27951 }
27953 /* walk_tree callback function for instantiation_dependent_expression_p,
27954 below. Returns non-zero if a dependent subexpression is found. */
27956 static tree
27959 {
27961 {
27962 /* We don't have to worry about decltype currently because decltype
27963 of an instantiation-dependent expr is a dependent type. This
27964 might change depending on the resolution of DR 1172. */
27967 }
27970 {
27971 /* Don't treat an argument list as dependent just because it has no
27972 TREE_TYPE. */
27983 /* We'll check value-dependence separately. */
27986 /* Handle expressions with type operands. */
27991 {
27996 {
27999 else
28000 {
28003 }
28004 }
28006 }
28010 /* In a template, finish_class_member_access_expr creates a
28011 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
28012 type-dependent, so that we can check access control at
28013 instantiation time (PR 42277). See also Core issue 1273. */
28020 else
28023 /* Treat statement-expressions as dependent. */
28027 /* Treat requires-expressions as dependent. */
28038 /* Before C++17, a noexcept-specifier isn't part of the function type
28039 so it doesn't affect type dependence, but we still want to consider it
28040 for instantiation dependence. */
28049 }
28053 else
28055 }
28057 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
28058 sense defined by the ABI:
28060 "An expression is instantiation-dependent if it is type-dependent
28061 or value-dependent, or it has a subexpression that is type-dependent
28062 or value-dependent."
28064 Except don't actually check value-dependence for unevaluated expressions,
28065 because in sizeof(i) we don't care about the value of i. Checking
28066 type-dependence will in turn check value-dependence of array bounds/template
28067 arguments as needed. */
28069 bool
28071 {
28072 tree result;
28083 }
28085 /* As above, but also check value-dependence of the expression as a whole. */
28087 bool
28089 {
28091 || (processing_template_decl
28094 }
28096 /* Like type_dependent_expression_p, but it also works while not processing
28097 a template definition, i.e. during substitution or mangling. */
28099 bool
28101 {
28107 }
28109 /* Returns TRUE if ARGS contains a type-dependent expression. */
28111 bool
28113 {
28115 tree arg;
28118 {
28121 }
28123 }
28125 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
28126 expressions) contains any type-dependent expressions. */
28128 bool
28130 {
28136 }
28138 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
28139 expressions) contains any value-dependent expressions. */
28141 bool
28143 {
28149 }
28151 /* Returns TRUE if the ARG (a template argument) is dependent. */
28153 bool
28155 {
28159 /* Assume a template argument that was wrongly written by the user
28160 is dependent. This is consistent with what
28161 any_dependent_template_arguments_p [that calls this function]
28162 does. */
28172 {
28175 /* A member template of a dependent class is not necessarily
28176 type-dependent, but it is a dependent template argument because it
28177 will be a member of an unknown specialization to that template. */
28180 }
28182 {
28188 }
28191 else
28193 }
28195 /* Identify any expressions that use function parms. */
28197 static tree
28199 {
28202 {
28205 }
28207 }
28209 /* Returns true if a type specialization formed using the template
28210 arguments ARGS needs to use structural equality. */
28212 bool
28214 {
28224 {
28227 {
28233 {
28234 /* Look inside the argument pack. */
28237 }
28240 {
28249 /* An any_targ_node argument (added by add_defaults_to_ttp)
28250 makes the corresponding specialization not canonicalizable,
28251 since template_args_equal always return true for it. We
28252 may see this when called from bind_template_template_parm. */
28254 /* Checking current_function_decl because this structural
28255 comparison is only necessary for redeclaration. */
28258 && (cp_walk_tree_without_duplicates
28260 /* The identity of a class template specialization that uses
28261 a function parameter depends on the identity of the function.
28262 And if this specialization appeared in the trailing return
28263 type thereof, we don't know the identity of the function
28264 (e.g. if it's a redeclaration or a new function) until we
28265 form its signature and go through duplicate_decls. Thus
28266 it's unsafe to decide on a canonical type now (which depends
28267 on the DECL_CONTEXT of the function parameter, which can get
28268 mutated after the fact by duplicate_decls), so just require
28269 structural equality in this case (PR52830). */
28271 }
28272 }
28273 }
28276 }
28278 /* Returns true if ARGS (a collection of template arguments) contains
28279 any dependent arguments. */
28281 bool
28283 {
28293 {
28298 }
28301 }
28303 /* Returns true if ARGS contains any errors. */
28305 bool
28307 {
28315 {
28318 else
28320 }
28326 {
28331 }
28334 }
28336 /* Returns TRUE if the template TMPL is type-dependent. */
28338 bool
28340 {
28342 {
28347 }
28349 /* Template template parameters are dependent. */
28353 /* So are names that have not been looked up. */
28357 }
28359 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
28361 bool
28363 {
28366 }
28368 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
28369 are dependent. */
28371 bool
28373 {
28380 {
28405 {
28409 }
28413 {
28417 {
28423 /* If this loop has a class iterator with != comparison
28424 with increment other than i++/++i/i--/--i, make sure the
28425 increment is constant. */
28428 {
28431 else
28435 }
28436 }
28437 }
28438 }
28441 }
28443 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
28444 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
28445 no such TYPE can be found. Note that this function peers inside
28446 uninstantiated templates and therefore should be used only in
28447 extremely limited situations. ONLY_CURRENT_P restricts this
28448 peering to the currently open classes hierarchy (which is required
28449 when comparing types). */
28451 tree
28453 {
28454 tree scope;
28455 tree name;
28456 tree decl;
28458 tree pushed_scope;
28459 tree result;
28464 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
28467 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
28468 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of a
28469 TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL
28470 representing the typedef. In that case TYPE_IDENTIFIER (type) is
28471 not the non-qualified identifier of the TYPENAME_TYPE anymore.
28472 So by getting the TYPE_IDENTIFIER of the _main declaration_ of
28473 the TYPENAME_TYPE instead, we avoid messing up with a possible
28474 typedef variant case. */
28477 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
28478 it first before we can figure out what NAME refers to. */
28480 {
28482 /* Given a class template A with a dependent base with nested type C,
28483 typedef typename A::C::C C will land us here, as trying to resolve
28484 the initial A::C leads to the local C typedef, which leads back to
28485 A::C::C. So we break the recursion now. */
28487 else
28489 }
28490 /* If we don't know what SCOPE refers to, then we cannot resolve the
28491 TYPENAME_TYPE. */
28494 /* If this is a typedef, we don't want to look inside (c++/11987). */
28497 /* If SCOPE isn't the template itself, it will not have a valid
28498 TYPE_FIELDS list. */
28500 /* scope is either the template itself or a compatible instantiation
28501 like X<T>, so look up the name in the original template. */
28503 /* If scope has no fields, it can't be a current instantiation. Check this
28504 before currently_open_class to avoid infinite recursion (71515). */
28507 /* If the SCOPE is not the current instantiation, there's no reason
28508 to look inside it. */
28511 /* Enter the SCOPE so that name lookup will be resolved as if we
28512 were in the class definition. In particular, SCOPE will no
28513 longer be considered a dependent type. */
28515 /* Look up the declaration. */
28517 tf_warning_or_error);
28521 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
28522 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
28528 {
28532 }
28535 {
28536 /* Obtain the template and the arguments. */
28539 {
28540 /* We get here with a plain identifier because a previous tentative
28541 parse of the nested-name-specifier as part of a ptr-operator saw
28542 ::template X<A>. The use of ::template is necessary in a
28543 ptr-operator, but wrong in a declarator-id.
28545 [temp.names]: In a qualified-id of a declarator-id, the keyword
28546 template shall not appear at the top level. */
28550 }
28552 /* Instantiate the template. */
28558 }
28560 /* Leave the SCOPE. */
28564 /* If we failed to resolve it, return the original typename. */
28568 /* If lookup found a typename type, resolve that too. */
28570 {
28571 /* Ill-formed programs can cause infinite recursion here, so we
28572 must catch that. */
28576 }
28578 /* Qualify the resulting type. */
28584 }
28586 /* EXPR is an expression which is not type-dependent. Return a proxy
28587 for EXPR that can be used to compute the types of larger
28588 expressions containing EXPR. */
28590 tree
28592 {
28594 tree inner_expr;
28596 /* When checking, try to get a constant value for all non-dependent
28597 expressions in order to expose bugs in *_dependent_expression_p
28598 and constexpr. This can affect code generation, see PR70704, so
28599 only do this for -fchecking=2. */
28602 /* Don't do this during nsdmi parsing as it can lead to
28603 unexpected recursive instantiations. */
28605 /* Don't do this during concept processing either and for
28606 the same reason. */
28612 /* Preserve OVERLOADs; the functions must be available to resolve
28613 types. */
28624 /* There is no need to return a proxy for a variable, parameter
28625 or enumerator. */
28629 /* Preserve string constants; conversions from string constants to
28630 "char *" are allowed, even though normally a "const char *"
28631 cannot be used to initialize a "char *". */
28634 /* Preserve void and arithmetic constants, as an optimization -- there is no
28635 reason to create a new node. */
28640 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
28641 There is at least one place where we want to know that a
28642 particular expression is a throw-expression: when checking a ?:
28643 expression, there are special rules if the second or third
28644 argument is a throw-expression. */
28648 /* Don't wrap an initializer list, we need to be able to look inside. */
28652 /* Don't wrap a dummy object, we need to be able to test for it. */
28670 /* If the type is unknown, it can't really be non-dependent */
28673 /* Otherwise, build a NON_DEPENDENT_EXPR. */
28676 }
28678 /* ARGS is a vector of expressions as arguments to a function call.
28679 Replace the arguments with equivalent non-dependent expressions.
28680 This modifies ARGS in place. */
28682 void
28684 {
28686 tree arg;
28689 {
28693 }
28694 }
28696 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
28697 TEMPLATE_TYPE_PARM with a level one deeper than the actual template parms,
28698 by default. If set_canonical is true, we set TYPE_CANONICAL on it. */
28700 static tree
28702 {
28718 }
28720 tree
28722 {
28724 }
28726 tree
28728 {
28730 }
28732 /* Return a C++17 deduction placeholder for class template TMPL.
28733 There are represented as an 'auto' with the special level 0 and
28734 CLASS_PLACEHOLDER_TEMPLATE set. */
28736 tree
28738 {
28741 /* Our canonical type depends on the placeholder. */
28744 }
28746 /* True iff T is a C++17 class template deduction placeholder. */
28748 bool
28750 {
28752 }
28754 /* Make a "constrained auto" type-specifier. This is an auto or
28755 decltype(auto) type with constraints that must be associated after
28756 deduction. The constraint is formed from the given concept CON
28757 and its optional sequence of template arguments ARGS.
28759 TYPE must be the result of make_auto_type or make_decltype_auto_type. */
28761 static tree
28763 {
28764 /* Build the constraint. */
28776 /* Our canonical type depends on the constraint. */
28779 /* Attach the constraint to the type declaration. */
28781 }
28783 /* Make a "constrained auto" type-specifier. */
28785 tree
28787 {
28790 }
28792 /* Make a "constrained decltype(auto)" type-specifier. */
28794 tree
28796 {
28799 }
28801 /* Returns true if the placeholder type constraint T has any dependent
28802 (explicit) template arguments. */
28804 static bool
28806 {
28811 {
28814 }
28821 }
28823 /* Build and return a concept definition. Like other templates, the
28824 CONCEPT_DECL node is wrapped by a TEMPLATE_DECL. This returns the
28825 the TEMPLATE_DECL. */
28827 tree
28829 {
28835 /* A concept-definition shall not have associated constraints. */
28837 {
28840 }
28842 /* A concept-definition shall appear in namespace scope. Templates
28843 aren't allowed in block scope, so we only need to check for class
28844 scope. */
28846 {
28849 }
28852 {
28855 }
28857 /* Initially build the concept declaration; its type is bool. */
28864 /* Push the enclosing template. */
28866 }
28868 /* Given type ARG, return std::initializer_list<ARG>. */
28870 static tree
28872 {
28876 {
28880 "deducing from brace-enclosed initializer list"
28884 }
28890 }
28892 /* Replace auto in TYPE with std::initializer_list<auto>. */
28894 static tree
28896 {
28903 }
28905 /* Hash traits for hashing possibly constrained 'auto'
28906 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
28909 {
28912 };
28914 /* Hash the 'auto' T. */
28916 inline hashval_t
28918 {
28920 /* Matching constrained-type-specifiers denote the same template
28921 parameter, so hash the constraint. */
28923 else
28924 /* But unconstrained autos are all separate, so just hash the pointer. */
28926 }
28928 /* Compare two 'auto's. */
28932 {
28939 /* Two unconstrained autos are distinct. */
28944 }
28946 /* for_each_template_parm callback for extract_autos: if t is a (possibly
28947 constrained) auto, add it to the vector. */
28949 static int
28951 {
28954 {
28955 /* All the autos were built with index 0; fix that up now. */
28959 /* If this is a repeated constrained-type-specifier, use the index we
28960 chose before. */
28962 else
28963 {
28964 /* Otherwise this is new, so use the current count. */
28967 }
28969 }
28971 /* Always keep walking. */
28973 }
28975 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
28976 says they can appear anywhere in the type. */
28978 static tree
28980 {
28988 {
28992 }
28995 }
28997 /* The stem for deduction guide names. */
29000 /* Return the name for a deduction guide for class template TMPL. */
29002 tree
29004 {
29015 }
29017 /* True if NAME is the name of a deduction guide. */
29019 bool
29021 {
29025 }
29027 /* True if FN is a deduction guide. */
29029 bool
29031 {
29036 }
29038 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
29040 bool
29042 {
29049 }
29051 /* True if FN is a guide generated from a constructor template. */
29053 bool
29055 {
29063 }
29065 /* True if FN is an aggregate initialization guide or the copy deduction
29066 guide. */
29068 bool
29070 {
29074 /* Explicitly declared. */
29077 /* Derived from a constructor. */
29080 }
29082 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
29083 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
29084 template parameter types. Note that the handling of template template
29085 parameters relies on current_template_parms being set appropriately for the
29086 new template. */
29088 static tree
29091 {
29097 tree newtype;
29100 {
29104 }
29105 else
29106 {
29109 {
29110 // Substitute once to fix references to other template parameters.
29113 // Now substitute again to reduce the level of the auto.
29116 }
29117 else
29120 }
29122 tree newdecl
29127 tree newidx;
29130 {
29139 {
29144 // First create a copy (ttargs) of tsubst_args with an
29145 // additional level for the template template parameter's own
29146 // template parameters (ttparms).
29147 tree ttparms = (INNERMOST_TEMPLATE_PARMS
29155 // Substitute ttargs into ttparms to fix references to
29156 // other template parameters.
29159 // Now substitute again with args based on tparms, to reduce
29160 // the level of the ttparms.
29163 complain);
29164 // Finally, tack the adjusted parms onto tparms.
29167 // As with all template template parms, the parameter list captured
29168 // by this template template parm that corresponds to its own level
29169 // should be empty. This avoids infinite recursion when structurally
29170 // comparing two such rewritten template template parms (PR102479).
29175 // All done.
29177 }
29181 else
29183 }
29184 else
29185 {
29187 tree newconst
29199 }
29202 }
29204 /* As rewrite_template_parm, but for the whole TREE_LIST representing a
29205 template parameter. */
29207 static tree
29210 {
29225 }
29227 /* Returns a C++17 class deduction guide template based on the constructor
29228 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
29229 guide, REFERENCE_TYPE for an implicit copy/move guide, or TREE_LIST for an
29230 aggregate initialization guide. OUTER_ARGS are the template arguments
29231 for the enclosing scope of the class. */
29233 static tree
29235 {
29239 location_t loc;
29243 {
29247 }
29250 {
29252 {
29256 else
29258 }
29261 else
29271 }
29272 else
29273 {
29279 fn_tmpl
29287 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
29288 fully specialized args for the enclosing class. Strip those off, as
29289 the deduction guide won't have those template parameters. */
29292 /* Discard the 'this' parameter. */
29300 {
29303 /* For a member template constructor, we need to flatten the two
29304 template parameter lists into one, and then adjust the function
29305 signature accordingly. This gets...complicated. */
29308 /* For a member template we should have two levels of parms/args, one
29309 for the class and one for the constructor. We stripped
29310 specialized args for further enclosing classes above. */
29314 /* Template args for translating references to the two-level template
29315 parameters into references to the one-level template parameters we
29316 are creating. */
29321 /* Template parms for the constructor template. */
29324 /* Template parms for the class template. */
29328 /* Template parms for the deduction guide start as a copy of the
29329 template parms for the class. We set current_template_parms for
29330 lookup_template_class_1. */
29336 /* Now we need to rewrite the constructor parms to append them to the
29337 class parms. */
29339 {
29343 tree newelt
29349 }
29351 /* Now we have a final set of template parms to substitute into the
29352 function signature. */
29359 {
29361 /* FIXME: We'd like to avoid substituting outer template
29362 arguments into the constraint ahead of time, but the
29363 construction of tsubst_args assumes that outer arguments
29364 are already substituted in. */
29367 }
29369 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped if
29370 cp_unevaluated_operand. */
29371 cp_evaluated ev;
29374 }
29375 else
29376 {
29377 /* Substitute in the same arguments to rewrite class members into
29378 references to members of an unknown specialization. */
29379 cp_evaluated ev;
29383 {
29385 /* FIXME: As above. */
29388 }
29389 }
29394 }
29397 {
29398 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
29402 }
29406 FUNCTION_DECL,
29421 }
29423 /* Add to LIST the member types for the reshaped initializer CTOR. */
29425 static tree
29427 {
29431 {
29435 {
29441 }
29445 /* Give the trailing pack expansion parameter a default argument to
29446 match aggregate initialization behavior, even if we deduce the
29447 length of the pack separately to more than we have initializers. */
29449 /* if ei is of array type and xi is a braced-init-list or string literal,
29450 Ti is an rvalue reference to the declared type of ei */
29455 {
29457 ftype = cp_build_qualified_type
29459 ftype = (cp_build_reference_type
29461 }
29463 }
29466 }
29468 /* Return whether ETYPE is, or is derived from, a specialization of TMPL. */
29470 static bool
29472 {
29478 tree tparms = (INNERMOST_TEMPLATE_PARMS
29485 }
29489 /* Return a C++20 aggregate deduction candidate for TYPE initialized from
29490 INIT. */
29492 static tree
29494 {
29502 {
29508 }
29510 /* We might be creating a guide for a class member template, e.g.,
29512 template<typename U> struct A {
29513 template<typename T> struct B { T t; };
29514 };
29516 At this point, A will have been instantiated. Below, we need to
29517 use both A<U>::B<T> (TEMPLATE_TYPE) and A<int>::B<T> (TYPE) types. */
29518 const bool member_template_p
29522 tree template_type = (member_template_p
29528 /* No aggregate candidate for copy-initialization. */
29530 {
29534 }
29536 /* If we encounter a problem, we just won't add the candidate. */
29541 {
29546 /* If we're creating a deduction guide for a member class template,
29547 we've used the original template pattern type for the reshape_init
29548 above; this is done because we want PARMS to be a template parameter
29549 type, something that can be deduced when used as a function template
29550 parameter. At this point the outer class template has already been
29551 partially instantiated (we deferred the deduction until the enclosing
29552 scope is non-dependent). Therefore we have to partially instantiate
29553 PARMS, so that its template level is properly reduced and we don't get
29554 mismatches when deducing types using the guide with PARMS. */
29556 {
29560 }
29561 }
29563 {
29566 len;
29568 {
29574 }
29575 }
29576 else
29577 /* Aggregate initialization doesn't apply to an initializer expression. */
29581 {
29587 }
29590 }
29592 /* UGUIDES are the deduction guides for the underlying template of alias
29593 template TMPL; adjust them to be deduction guides for TMPL. */
29595 static tree
29597 {
29598 /* [over.match.class.deduct]: When resolving a placeholder for a deduced
29599 class type (9.2.8.2) where the template-name names an alias template A,
29600 the defining-type-id of A must be of the form
29602 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
29604 as specified in 9.2.8.2. The guides of A are the set of functions or
29605 function templates formed as follows. For each function or function
29606 template f in the guides of the template named by the simple-template-id
29607 of the defining-type-id, the template arguments of the return type of f
29608 are deduced from the defining-type-id of A according to the process in
29609 13.10.2.5 with the exception that deduction does not fail if not all
29610 template arguments are deduced. Let g denote the result of substituting
29611 these deductions into f. If substitution succeeds, form a function or
29612 function template f' with the following properties and add it to the set
29613 of guides of A:
29615 * The function type of f' is the function type of g.
29617 * If f is a function template, f' is a function template whose template
29618 parameter list consists of all the template parameters of A (including
29619 their default template arguments) that appear in the above deductions or
29620 (recursively) in their default template arguments, followed by the
29621 template parameters of f that were not deduced (including their default
29622 template arguments), otherwise f' is not a function template.
29624 * The associated constraints (13.5.2) are the conjunction of the
29625 associated constraints of g and a constraint that is satisfied if and only
29626 if the arguments of A are deducible (see below) from the return type.
29628 * If f is a copy deduction candidate (12.4.1.8), then f' is considered to
29629 be so as well.
29631 * If f was generated from a deduction-guide (12.4.1.8), then f' is
29632 considered to be so as well.
29634 * The explicit-specifier of f' is the explicit-specifier of g (if
29635 any). */
29637 /* This implementation differs from the above in two significant ways:
29639 1) We include all template parameters of A, not just some.
29640 2) The added constraint is same_type instead of deducible.
29642 I believe that while it's probably possible to construct a testcase that
29643 behaves differently with this simplification, it should have the same
29644 effect for real uses. Including all template parameters means that we
29645 deduce all parameters of A when resolving the call, so when we're in the
29646 constraint we don't need to deduce them again, we can just check whether
29647 the deduction produced the desired result. */
29656 {
29663 {
29667 /* Deduce template arguments for f from the type-id of A. */
29675 /* The number of parms for f' is the number of parms for A plus
29676 non-deduced parms of f. */
29684 /* Set current_template_parms as in build_deduction_guide. */
29689 /* First copy over the parms of A. */
29692 /* Now rewrite the non-deduced parms of f. */
29695 {
29703 }
29706 /* Substitute the deduced arguments plus the rewritten template
29707 parameters into f to get g. This covers the type, copyness,
29708 guideness, and explicit-specifier. */
29709 tree g;
29710 {
29711 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped
29712 if cp_unevaluated_operand. */
29713 cp_evaluated ev;
29715 }
29726 /* Substitute the associated constraints. */
29733 /* Add a constraint that the return type matches the instantiation of
29734 A with the same template arguments. */
29737 /* FIXME this should mean they don't compare as equivalent. */
29739 {
29742 }
29745 {
29748 }
29749 }
29750 else
29751 {
29752 /* For a non-template deduction guide, if the arguments of A aren't
29753 deducible from the return type, don't add the candidate. */
29761 }
29764 }
29767 }
29769 /* Return artificial deduction guides built from the constructors of class
29770 template TMPL. */
29772 static tree
29774 {
29779 {
29784 }
29789 {
29790 /* Skip inherited constructors. */
29796 }
29798 /* Add implicit default constructor deduction guide. */
29800 {
29802 complain);
29804 }
29806 /* Add copy guide. */
29807 {
29810 complain);
29812 }
29815 }
29819 /* Return the non-aggregate deduction guides for deducible template TMPL. The
29820 aggregate candidate is added separately because it depends on the
29821 initializer. Set ANY_DGUIDES_P if we find a non-implicit deduction
29822 guide. */
29824 static tree
29826 {
29829 {
29833 complain);
29834 }
29835 else
29836 {
29842 else
29844 }
29846 /* Cache the deduction guides for a template. We also remember the result of
29847 lookup, and rebuild everything if it changes; should be very rare. */
29851 {
29855 }
29856 else
29857 {
29860 }
29865 else
29866 {
29870 }
29874 }
29876 /* Return whether TMPL is a (class template argument-) deducible template. */
29878 bool
29880 {
29881 /* A deducible template is either a class template or is an alias template
29882 whose defining-type-id is of the form
29884 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
29886 where the nested-name-specifier (if any) is non-dependent and the
29887 template-name of the simple-template-id names a deducible template. */
29898 }
29900 /* Deduce template arguments for the class template placeholder PTYPE for
29901 template TMPL based on the initializer INIT, and return the resulting
29902 type. */
29904 static tree
29907 {
29908 /* We should have handled this in the caller. */
29912 /* If the class was erroneous, don't try to deduce, because that
29913 can generate a lot of diagnostic. */
29919 /* Wait until the enclosing scope is non-dependent. */
29924 /* Initializing one placeholder from another. */
29935 {
29939 }
29941 {
29943 {
29944 /* Be permissive with equivalent alias templates. */
29947 bool complained
29949 "alias template deduction only available "
29954 {
29957 }
29958 }
29959 else
29961 }
29963 /* Wait until the initializer is non-dependent. */
29967 /* Don't bother with the alias rules for an equivalent template. */
29980 {
29985 {
29986 /* As an exception, the first phase in 16.3.1.7 (considering the
29987 initializer list as a single argument) is omitted if the
29988 initializer list consists of a single expression of type cv U,
29989 where U is a specialization of C or a class derived from a
29990 specialization of C. */
29994 }
29997 else
29999 }
30002 else
30005 /* Do this now to avoid problems with erroneous args later on. */
30015 /* Prune explicit deduction guides in copy-initialization context (but
30016 not copy-list-initialization). */
30019 {
30025 {
30026 /* Found a nonconverting guide, prune the candidates. */
30033 }
30034 }
30042 /* If this is list-initialization and the class has a list constructor, first
30043 try deducing from the list as a single argument, as [over.match.list]. */
30047 {
30051 }
30053 {
30057 {
30058 /* That didn't work, now try treating the list as a sequence of
30059 arguments. */
30062 }
30063 }
30066 {
30068 " of %qT, as it has no non-explicit deduction guides or "
30071 }
30073 {
30077 }
30083 {
30085 {
30091 }
30093 }
30094 /* [over.match.list]/1: In copy-list-initialization, if an explicit
30095 constructor is chosen, the initialization is ill-formed. */
30097 {
30099 {
30101 {
30102 // TODO: Pass down location from cp_finish_decl.
30104 "explicit deduction guide selected in "
30109 }
30111 }
30112 }
30114 /* If CTAD succeeded but the type doesn't have any explicit deduction
30115 guides, this deduction might not be what the user intended. */
30117 {
30121 "%qT may not intend to support class template argument "
30125 }
30129 }
30131 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
30132 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
30133 The CONTEXT determines the context in which auto deduction is performed
30134 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
30136 OUTER_TARGS is used during template argument deduction (context == adc_unify)
30137 to properly substitute the result. It's also used in the adc_unify and
30138 adc_requirement contexts to communicate the necessary template arguments
30139 to satisfaction. OUTER_TARGS is ignored in other contexts.
30141 For partial-concept-ids, extra args may be appended to the list of deduced
30142 template arguments prior to determining constraint satisfaction. */
30144 tree
30148 {
30154 /* Defining a subset of type-dependent expressions that we can deduce
30155 from ahead of time isn't worth the trouble. */
30158 /* Similarly, we can't deduce from another undeduced decl. */
30162 /* We may be doing a partial substitution, but we still want to replace
30163 auto_node. */
30167 /* C++17 class template argument deduction. */
30171 /* Nothing we can do with this, even in deduction context. */
30176 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
30177 with either a new invented type template parameter U or, if the
30178 initializer is a braced-init-list (8.5.4), with
30179 std::initializer_list<U>. */
30181 {
30186 else
30187 {
30189 {
30193 "for deduction to %<std::initializer_list%>, use copy-"
30195 }
30197 }
30198 }
30204 {
30205 /* We don't recurse here because we can't deduce from a nested
30206 initializer_list. */
30210 }
30211 else
30214 tree targs;
30219 {
30220 /* [dcl.struct.bind]/1 - if decomposition declaration has no ref-qualifiers
30221 and initializer has array type, deduce cv-qualified array type. */
30224 }
30226 {
30227 /* Figure out if INIT is an unparenthesized id-expression or an
30228 unparenthesized class member access. */
30230 /* We need to be able to tell '(r)' and 'r' apart (when it's of
30231 reference type). Only the latter is an id-expression. */
30245 }
30246 else
30247 {
30252 tree tparms;
30256 else
30257 {
30261 }
30265 DEDUCE_CALL,
30268 {
30270 /* Try again at instantiation time. */
30274 /* If type is error_mark_node a diagnostic must have been
30275 emitted by now. Also, having a mention to '<type error>'
30276 in the diagnostic is not really useful to the user. */
30277 {
30280 && (auto_node
30284 init);
30285 else
30288 DEDUCE_CALL,
30290 }
30292 }
30293 }
30295 /* Check any placeholder constraints against the deduced type. */
30299 {
30301 {
30306 /* If the constraint is dependent, we need to wait until
30307 instantiation time to resolve the placeholder. */
30310 }
30317 {
30321 {
30322 /* As in satisfy_declaration_constraints. */
30326 else
30328 }
30329 }
30333 /* HACK: Compensate for callers not always communicating all levels of
30334 outer template arguments by filling in the outermost missing levels
30335 with dummy levels before checking satisfaction. We'll still crash
30336 if the constraint depends on a template argument belonging to one of
30337 these missing levels, but this hack otherwise allows us to handle a
30338 large subset of possible constraints (including all non-dependent
30339 constraints). */
30342 {
30347 }
30350 {
30352 {
30353 auto_diagnostic_group d;
30355 {
30373 }
30375 }
30377 }
30378 }
30381 /* The outer template arguments are already substituted into type
30388 }
30390 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
30391 result. */
30393 tree
30395 {
30397 {
30400 }
30404 {
30405 /* In an abbreviated function template we didn't know we were dealing
30406 with a function template when we saw the auto return type, so rebuild
30407 the return type using an auto with the correct level. */
30412 auto_vec);
30413 /* Also rebuild the constraint info in terms of the new auto. */
30421 }
30423 }
30425 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
30426 'decltype(auto)' or a deduced class template. */
30428 bool
30430 {
30435 else
30437 }
30439 /* for_each_template_parm callback for type_uses_auto. */
30441 int
30443 {
30445 }
30447 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
30448 a use of `auto'. Returns NULL_TREE otherwise. */
30450 tree
30452 {
30456 {
30457 /* The Concepts TS allows multiple autos in one type-specifier; just
30458 return the first one we find, do_auto_deduction will collect all of
30459 them. */
30463 else
30465 }
30466 else
30468 }
30470 /* Report ill-formed occurrences of auto types in ARGUMENTS. If
30471 concepts are enabled, auto is acceptable in template arguments, but
30472 only when TEMPL identifies a template class. Return TRUE if any
30473 such errors were reported. */
30475 bool
30477 {
30479 /* Only the concepts TS allows 'auto' as a type-id; it'd otherwise
30480 have already been rejected by the parser more generally. */
30483 /* If there were previous errors, nevermind. */
30487 /* If TMPL is an identifier, we're parsing and we can't tell yet
30488 whether TMPL is supposed to be a type, a function or a variable.
30489 We'll only be able to tell during template substitution, so we
30490 expect to be called again then. If concepts are enabled and we
30491 know we have a type, we're ok. */
30498 /* Quickly search for any occurrences of auto; usually there won't
30499 be any, and then we'll avoid allocating the vector. */
30507 {
30512 }
30515 }
30517 /* Recursively walk over && expressions searching for EXPR. Return a reference
30518 to that expression. */
30521 {
30525 {
30530 }
30532 }
30534 /* Convert the generic type parameters in PARM that match the types given in the
30535 range [START_IDX, END_IDX) from the current_template_parms into generic type
30536 packs. */
30538 tree
30540 {
30551 {
30552 /* Create a distinct parameter pack type from the current parm and add it
30553 to the replacement args to tsubst below into the generic function
30554 parameter. */
30568 /* Replace the current template parameter with new pack. */
30571 /* Surgically adjust the associated constraint of adjusted parameter
30572 and it's corresponding contribution to the current template
30573 requirements. */
30575 {
30581 /* If there was a constraint, we also need to replace that in
30582 the template requirements, which we've already built. */
30586 }
30587 }
30593 /* If there are more levels then build up the replacement with the outer
30594 template parms. */
30598 replacement);
30601 }
30603 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
30604 0..N-1. */
30606 void
30608 {
30611 integer_type_node,
30612 NULL_TREE),
30616 CP_BUILT_IN_INTEGER_PACK);
30617 }
30619 /* Walk the decl or type specialization table calling FN on each
30620 entry. */
30622 void
30626 {
30632 }
30634 /* Lookup the specialization of *ELT, in the decl or type
30635 specialization table. Return the SPEC that's already there, or
30636 NULL if nothing. */
30638 tree
30640 {
30650 }
30652 /* Return flags encoding whether SPEC is on the instantiation and/or
30653 specialization lists of TMPL. */
30655 unsigned
30657 {
30663 {
30666 }
30671 /* Only need to search if DECL is a partial specialization. */
30675 {
30678 }
30681 }
30683 /* Add a new specialization described by SPEC. DECL is the
30684 maybe-template decl and FLAGS is as returned from
30685 get_mergeable_specialization_flags. */
30687 void
30690 {
30693 {
30702 {
30705 }
30706 }
30709 {
30712 /* We don't distinguish different constrained partial type
30713 specializations, so there could be duplicates. Everything else
30714 must be new. */
30716 {
30722 }
30723 }
30730 {
30731 /* A partial specialization. */
30736 }
30737 }
30739 /* Set up the hash tables for template instantiations. */
30741 void
30743 {
30749 }
30751 /* Print stats about the template hash tables for -fstats. */
30753 void
30755 {
30764 }
30766 #if CHECKING_P
30770 /* Verify that build_non_dependent_expr () works, for various expressions,
30771 and that location wrappers don't affect the results. */
30773 static void
30775 {
30778 /* Verify constants, without and with location wrappers. */
30795 }
30797 /* Verify that type_dependent_expression_p () works correctly, even
30798 in the presence of location wrapper nodes. */
30800 static void
30802 {
30807 /* If no templates are involved, nothing is type-dependent. */
30813 /* Within a template, an unresolved name is always type-dependent. */
30816 /* Ensure it copes with NULL_TREE and errors. */
30820 /* A USING_DECL in a template should be type-dependent, even if wrapped
30821 with a location wrapper (PR c++/83799). */
30830 }
30832 /* Run all of the selftests within this file. */
30834 void
30836 {
30839 }