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1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2021 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 };
158 tree);
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 alias template (needed by instantiate_decl). */
229 void
231 {
240 /* An artificial deduction guide should have the same access as
241 the constructor. */
243 else
247 {
250 }
251 }
253 /* Restore the scope set up by push_access_scope. T is the node we
254 are processing. */
256 void
258 {
266 else
268 }
270 /* Do any processing required when DECL (a member template
271 declaration) is finished. Returns the TEMPLATE_DECL corresponding
272 to DECL, unless it is a specialization, in which case the DECL
273 itself is returned. */
275 tree
277 {
284 {
285 tree type;
293 {
297 }
299 }
304 {
306 {
309 }
310 else
312 }
313 else
318 }
320 /* Create a template info node. */
322 tree
324 {
329 }
331 /* Return the template info node corresponding to T, whatever T is. */
333 tree
335 {
357 }
359 /* Returns the template nesting level of the indicated class TYPE.
361 For example, in:
362 template <class T>
363 struct A
364 {
365 template <class U>
366 struct B {};
367 };
369 A<T>::B<U> has depth two, while A<T> has depth one.
370 Both A<T>::B<int> and A<int>::B<U> have depth one, if
371 they are instantiations, not specializations.
373 This function is guaranteed to return 0 if passed NULL_TREE so
374 that, for example, `template_class_depth (current_class_type)' is
375 always safe. */
377 int
379 {
383 {
391 {
394 else
396 }
399 else
401 }
404 }
406 /* Return TRUE if NODE instantiates a template that has arguments of
407 its own, be it directly a primary template or indirectly through a
408 partial specializations. */
409 static bool
411 {
423 /* So now we know we have a specialization, but it could be a full
424 or a partial specialization. To tell which, compare the depth of
425 its template arguments with those of its context. */
434 }
436 /* Subroutine of maybe_begin_member_template_processing.
437 Returns true if processing DECL needs us to push template parms. */
439 static bool
441 {
447 }
449 /* Subroutine of maybe_begin_member_template_processing.
450 Push the template parms in PARMS, starting from LEVELS steps into the
451 chain, and ending at the beginning, since template parms are listed
452 innermost first. */
454 static void
456 {
464 current_template_parms
470 NULL);
472 {
481 {
488 /* Push the CONST_DECL. */
494 }
495 }
496 }
498 /* Restore the template parameter context for a member template, a
499 friend template defined in a class definition, or a non-template
500 member of template class. */
502 void
504 {
505 tree parms;
510 {
513 /* Disregard full specializations (c++/60999). */
516 }
519 {
524 {
527 }
530 }
532 /* Remember how many levels of template parameters we pushed so that
533 we can pop them later. */
535 }
537 /* Undo the effects of maybe_begin_member_template_processing. */
539 void
541 {
550 {
554 }
555 }
557 /* Return a new template argument vector which contains all of ARGS,
558 but has as its innermost set of arguments the EXTRA_ARGS. */
560 tree
562 {
563 tree new_args;
581 }
583 /* Like add_to_template_args, but only the outermost ARGS are added to
584 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
585 (EXTRA_ARGS) levels are added. This function is used to combine
586 the template arguments from a partial instantiation with the
587 template arguments used to attain the full instantiation from the
588 partial instantiation.
590 If ARGS is a TEMPLATE_DECL, use its parameters as args. */
592 tree
594 {
595 tree new_args;
600 {
603 }
605 /* If there are more levels of EXTRA_ARGS than there are ARGS,
606 something very fishy is going on. */
609 /* If *all* the new arguments will be the EXTRA_ARGS, just return
610 them. */
614 /* For the moment, we make ARGS look like it contains fewer levels. */
619 /* Now, we restore ARGS to its full dimensions. */
623 }
625 /* Return the N levels of innermost template arguments from the ARGS. */
627 tree
629 {
630 tree new_args;
636 /* If N is 1, just return the innermost set of template arguments. */
640 /* If we're not removing anything, just return the arguments we were
641 given. */
647 /* Make a new set of arguments, not containing the outer arguments. */
654 }
656 /* The inverse of get_innermost_template_args: Return all but the innermost
657 EXTRA_LEVELS levels of template arguments from the ARGS. */
659 static tree
661 {
662 tree new_args;
668 /* If N is 1, just return the outermost set of template arguments. */
672 /* If we're not removing anything, just return the arguments we were
673 given. */
678 /* Make a new set of arguments, not containing the inner arguments. */
685 }
687 /* We've got a template header coming up; push to a new level for storing
688 the parms. */
690 void
692 {
693 /* We use a non-tag-transparent scope here, which causes pushtag to
694 put tags in this scope, rather than in the enclosing class or
695 namespace scope. This is the right thing, since we want
696 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
697 global template class, push_template_decl handles putting the
698 TEMPLATE_DECL into top-level scope. For a nested template class,
699 e.g.:
701 template <class T> struct S1 {
702 template <class T> struct S2 {};
703 };
705 pushtag contains special code to insert the TEMPLATE_DECL for S2
706 at the right scope. */
712 /* Add a dummy parameter level while we process the parameter list. */
713 current_template_parms
716 current_template_parms);
717 }
719 /* This routine is called when a specialization is declared. If it is
720 invalid to declare a specialization here, an error is reported and
721 false is returned, otherwise this routine will return true. */
723 static bool
725 {
728 /* [temp.expl.spec]
730 An explicit specialization shall be declared in the namespace of
731 which the template is a member, or, for member templates, in the
732 namespace of which the enclosing class or enclosing class
733 template is a member. An explicit specialization of a member
734 function, member class or static data member of a class template
735 shall be declared in the namespace of which the class template
736 is a member. */
738 {
741 }
743 /* [temp.expl.spec]
745 In an explicit specialization declaration for a member of a class
746 template or a member template that appears in namespace scope,
747 the member template and some of its enclosing class templates may
748 remain unspecialized, except that the declaration shall not
749 explicitly specialize a class member template if its enclosing
750 class templates are not explicitly specialized as well. */
752 {
755 }
758 }
760 /* We've just seen template <>. */
762 bool
764 {
768 }
770 /* Called at then end of processing a declaration preceded by
771 template<>. */
773 void
775 {
778 }
780 /* Any template <>'s that we have seen thus far are not referring to a
781 function specialization. */
783 void
785 {
788 }
790 /* We've just seen a template header. If SPECIALIZATION is nonzero,
791 it was of the form template <>. */
793 static void
795 {
797 template_header_count++;
798 }
800 /* We're beginning an explicit instantiation. */
802 void
804 {
807 }
810 void
812 {
815 }
817 /* An explicit specialization or partial specialization of TMPL is being
818 declared. Check that the namespace in which the specialization is
819 occurring is permissible. Returns false iff it is invalid to
820 specialize TMPL in the current namespace. */
822 static bool
824 {
827 /* [tmpl.expl.spec]
829 An explicit specialization shall be declared in a namespace enclosing the
830 specialized template. An explicit specialization whose declarator-id is
831 not qualified shall be declared in the nearest enclosing namespace of the
832 template, or, if the namespace is inline (7.3.1), any namespace from its
833 enclosing namespace set. */
836 {
839 }
842 /* Same or enclosing namespace. */
844 else
845 {
846 auto_diagnostic_group d;
852 }
853 }
855 /* SPEC is an explicit instantiation. Check that it is valid to
856 perform this explicit instantiation in the current namespace. */
858 static void
860 {
861 tree ns;
863 /* DR 275: An explicit instantiation shall appear in an enclosing
864 namespace of its template. */
870 }
872 /* Returns the type of a template specialization only if that
873 specialization needs to be defined. Otherwise (e.g., if the type has
874 already been defined), the function returns NULL_TREE. */
876 static tree
878 {
879 /* An implicit instantiation of an incomplete type implies
880 the definition of a new class template.
882 template<typename T>
883 struct S;
885 template<typename T>
886 struct S<T*>;
888 Here, S<T*> is an implicit instantiation of S whose type
889 is incomplete. */
893 /* It can also be the case that TYPE is a completed specialization.
894 Continuing the previous example, suppose we also declare:
896 template<typename T>
897 requires Integral<T>
898 struct S<T*>;
900 Here, S<T*> refers to the specialization S<T*> defined
901 above. However, we need to differentiate definitions because
902 we intend to define a new partial specialization. In this case,
903 we rely on the fact that the constraints are different for
904 this declaration than that above.
906 Note that we also get here for injected class names and
907 late-parsed template definitions. We must ensure that we
908 do not create new type declarations for those cases. */
910 {
914 /* If there are no template parameters, this cannot be a new
915 partial template specialization? */
919 /* The injected-class-name is not a new partial specialization. */
923 /* If the constraints are not the same as those of the primary
924 then, we can probably create a new specialization. */
928 {
932 }
934 /* Also, if there's a pre-existing specialization with matching
935 constraints, then this also isn't new. */
938 {
946 }
948 /* Create a new type node (and corresponding type decl)
949 for the newly declared specialization. */
954 /* We only need a separate type node for storing the definition of this
955 partial specialization; uses of S<T*> are unconstrained, so all are
956 equivalent. So keep TYPE_CANONICAL the same. */
959 /* Build the corresponding type decl. */
970 }
973 }
975 /* The TYPE is being declared. If it is a template type, that means it
976 is a partial specialization. Do appropriate error-checking. */
978 tree
980 {
981 tree context;
986 /* A lambda that appears in specialization context is not itself a
987 specialization. */
991 /* An injected-class-name is not a specialization. */
996 {
1000 }
1005 {
1011 else
1014 }
1016 {
1017 /* This is for ordinary explicit specialization and partial
1018 specialization of a template class such as:
1020 template <> class C<int>;
1022 or:
1024 template <class T> class C<T*>;
1026 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
1029 {
1036 {
1041 }
1042 }
1048 /* Trying to define a specialization either without a template<> header
1049 or in an inappropriate place. We've already given an error, so just
1050 bail now so we don't actually define the specialization. */
1052 }
1058 {
1059 /* This is for an explicit specialization of member class
1060 template according to [temp.expl.spec/18]:
1062 template <> template <class U> class C<int>::D;
1064 The context `C<int>' must be an implicit instantiation.
1065 Otherwise this is just a member class template declared
1066 earlier like:
1068 template <> class C<int> { template <class U> class D; };
1069 template <> template <class U> class C<int>::D;
1071 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1072 while in the second case, `C<int>::D' is a primary template
1073 and `C<T>::D' may not exist. */
1077 {
1078 tree t;
1083 {
1086 type))
1089 }
1091 /* Check for invalid specialization after instantiation:
1093 template <> template <> class C<int>::D<int>;
1094 template <> template <class U> class C<int>::D; */
1098 {
1102 {
1103 /* We already have a full specialization of this partial
1104 instantiation, or a full specialization has been
1105 looked up but not instantiated. Reassign it to the
1106 new member specialization template. */
1107 spec_entry elt;
1120 spec_entry **slot
1125 }
1126 else
1127 /* But if we've had an implicit instantiation, that's a
1128 problem ([temp.expl.spec]/6). */
1131 }
1133 /* Mark TYPE as a specialization. And as a result, we only
1134 have one level of template argument for the innermost
1135 class template. */
1140 }
1141 }
1143 {
1144 /* Someday C++0x may allow for enum template specialization. */
1149 else
1150 {
1153 }
1154 }
1157 }
1159 /* Returns nonzero if we can optimize the retrieval of specializations
1160 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1161 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1165 {
1168 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1169 parameter. */
1171 /* The optimized lookup depends on the fact that the
1172 template arguments for the member function template apply
1173 purely to the containing class, which is not true if the
1174 containing class is an explicit or partial
1175 specialization. */
1179 /* It is possible to have a template that is not a member
1180 template and is not a member of a template class:
1182 template <typename T>
1183 struct S { friend A::f(); };
1185 Here, the friend function is a template, but the context does
1186 not have template information. The optimized lookup relies
1187 on having ARGS be the template arguments for both the class
1188 and the function template. */
1190 }
1192 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1193 gone through coerce_template_parms by now. */
1195 static void
1197 {
1199 {
1208 /* Allow typedefs on the type of a non-type argument, since a
1210 else
1212 }
1213 }
1215 static void
1217 {
1222 }
1224 /* Retrieve the specialization (in the sense of [temp.spec] - a
1225 specialization is either an instantiation or an explicit
1226 specialization) of TMPL for the given template ARGS. If there is
1227 no such specialization, return NULL_TREE. The ARGS are a vector of
1228 arguments, or a vector of vectors of arguments, in the case of
1229 templates with more than one level of parameters.
1231 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1232 then we search for a partial specialization matching ARGS. This
1233 parameter is ignored if TMPL is not a class template.
1235 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1236 result is a NONTYPE_ARGUMENT_PACK. */
1238 static tree
1240 {
1250 /* There should be as many levels of arguments as there are
1251 levels of parameters. */
1260 /* Lambda functions in templates aren't instantiated normally, but through
1261 tsubst_lambda_expr. */
1266 {
1267 /* The template arguments actually apply to the containing
1268 class. Find the class specialization with those
1269 arguments. */
1271 tree class_specialization
1276 /* Find the instance of TMPL. */
1279 {
1283 /* using-declarations can bring in a different
1284 instantiation of tmpl as a member of a different
1285 instantiation of tmpl's class. We don't want those
1286 here. */
1289 }
1291 }
1292 else
1293 {
1295 spec_entry elt;
1304 else
1312 }
1315 }
1317 /* Like retrieve_specialization, but for local declarations. */
1319 tree
1321 {
1327 }
1329 /* Returns nonzero iff DECL is a specialization of TMPL. */
1331 int
1333 {
1334 tree t;
1337 {
1343 }
1344 else
1345 {
1354 }
1357 }
1359 /* Returns nonzero iff DECL is a specialization of friend declaration
1360 FRIEND_DECL according to [temp.friend]. */
1362 bool
1364 {
1371 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1372 of a template class, we want to check if DECL is a specialization
1373 if this. */
1377 {
1378 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1381 }
1386 /* There is nothing to do if this is not a template friend. */
1393 /* [temp.friend/6]
1394 A member of a class template may be declared to be a friend of a
1395 non-template class. In this case, the corresponding member of
1396 every specialization of the class template is a friend of the
1397 class granting friendship.
1399 For example, given a template friend declaration
1401 template <class T> friend void A<T>::f();
1403 the member function below is considered a friend
1405 template <> struct A<int> {
1406 void f();
1407 };
1409 For this type of template friend, TEMPLATE_DEPTH below will be
1410 nonzero. To determine if DECL is a friend of FRIEND, we first
1411 check if the enclosing class is a specialization of another. */
1418 {
1419 /* Next, we check the members themselves. In order to handle
1420 a few tricky cases, such as when FRIEND_DECL's are
1422 template <class T> friend void A<T>::g(T t);
1423 template <class T> template <T t> friend void A<T>::h();
1425 and DECL's are
1427 void A<int>::g(int);
1428 template <int> void A<int>::h();
1430 we need to figure out ARGS, the template arguments from
1431 the context of DECL. This is required for template substitution
1432 of `T' in the function parameter of `g' and template parameter
1433 of `h' in the above examples. Here ARGS corresponds to `int'. */
1440 {
1442 {
1445 else
1447 current_depth++;
1448 }
1450 }
1453 {
1455 tree friend_type;
1456 tree decl_type;
1457 tree friend_args_type;
1458 tree decl_args_type;
1460 /* Make sure that both DECL and FRIEND_DECL are templates or
1461 non-templates. */
1467 {
1468 /* If both are templates, check template parameter list. */
1469 tree friend_parms
1474 friend_parms))
1478 }
1479 else
1487 /* Check if return types match. */
1491 /* Check if function parameter types match, ignoring the
1492 `this' parameter. */
1501 }
1502 else
1503 {
1504 /* DECL is a TYPE_DECL */
1508 /* Make sure that both DECL and FRIEND_DECL are templates or
1509 non-templates. */
1510 is_template
1517 {
1518 tree friend_parms;
1519 /* If both are templates, check the name of the two
1520 TEMPLATE_DECL's first because is_friend didn't. */
1525 /* Now check template parameter list. */
1526 friend_parms
1529 return comp_template_parms
1531 friend_parms);
1532 }
1533 else
1536 }
1537 }
1539 }
1541 /* Register the specialization SPEC as a specialization of TMPL with
1542 the indicated ARGS. IS_FRIEND indicates whether the specialization
1543 is actually just a friend declaration. ATTRLIST is the list of
1544 attributes that the specialization is declared with or NULL when
1545 it isn't. Returns SPEC, or an equivalent prior declaration, if
1546 available.
1548 We also store instantiations of field packs in the hash table, even
1549 though they are not themselves templates, to make lookup easier. */
1551 static tree
1553 hashval_t hash)
1554 {
1555 tree fn;
1557 spec_entry elt;
1565 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1566 register it; we want the corresponding TEMPLATE_DECL instead.
1567 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1568 the more obvious `uses_template_parms (spec)' to avoid problems
1569 with default function arguments. In particular, given
1570 something like this:
1572 template <class T> void f(T t1, T t = T())
1574 the default argument expression is not substituted for in an
1575 instantiation unless and until it is actually needed. */
1579 /* We don't put these specializations in the hash table, but we might
1580 want to give an error about a mismatch. */
1582 else
1583 {
1594 else
1596 }
1598 /* We can sometimes try to re-register a specialization that we've
1599 already got. In particular, regenerate_decl_from_template calls
1600 duplicate_decls which will update the specialization list. But,
1601 we'll still get called again here anyhow. It's more convenient
1602 to simply allow this than to try to prevent it. */
1606 {
1608 {
1611 {
1613 fn);
1615 }
1616 else
1617 {
1618 tree clone;
1619 /* This situation should occur only if the first
1620 specialization is an implicit instantiation, the
1621 second is an explicit specialization, and the
1622 implicit instantiation has not yet been used. That
1623 situation can occur if we have implicitly
1624 instantiated a member function and then specialized
1625 it later.
1627 We can also wind up here if a friend declaration that
1628 looked like an instantiation turns out to be a
1629 specialization:
1631 template <class T> void foo(T);
1632 class S { friend void foo<>(int) };
1633 template <> void foo(int);
1635 We transform the existing DECL in place so that any
1636 pointers to it become pointers to the updated
1637 declaration.
1639 If there was a definition for the template, but not
1640 for the specialization, we want this to look as if
1641 there were no definition, and vice versa. */
1644 /* The call to duplicate_decls will have applied
1645 [temp.expl.spec]:
1647 An explicit specialization of a function template
1648 is inline only if it is explicitly declared to be,
1649 and independently of whether its function template
1650 is.
1652 to the primary function; now copy the inline bits to
1653 the various clones. */
1655 {
1662 }
1666 }
1667 }
1669 {
1672 /* We've already complained in duplicate_decls. */
1676 /* Dup decl failed, but this is a new definition. Set the
1677 line number so any errors match this new
1678 definition. */
1682 }
1683 }
1687 /* A specialization must be declared in the same namespace as the
1688 template it is specializing. */
1694 {
1703 /* If TMPL is a forward declaration of a template function, keep a list
1704 of all specializations in case we need to reassign them to a friend
1705 template later in tsubst_friend_function.
1707 Also keep a list of all variable template instantiations so that
1708 process_partial_specialization can check whether a later partial
1709 specialization would have used it. */
1712 }
1715 }
1717 /* Restricts tree and type comparisons. */
1721 /* Returns true iff two spec_entry nodes are equivalent. */
1723 bool
1725 {
1734 /* tmpl could be a FIELD_DECL for a capture pack. */
1738 {
1739 /* Partial specializations of a variable template can be distinguished by
1740 constraints. */
1744 }
1750 }
1752 /* Returns a hash for a template TMPL and template arguments ARGS. */
1754 static hashval_t
1756 {
1759 }
1761 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1762 ignoring SPEC. */
1764 hashval_t
1766 {
1768 }
1770 /* Recursively calculate a hash value for a template argument ARG, for use
1771 in the hash tables of template specializations. We must be
1772 careful to (at least) skip the same entities template_args_equal
1773 does. */
1775 hashval_t
1777 {
1782 /* Strip nop-like things, but not the same as STRIP_NOPS. */
1793 {
1828 {
1833 {
1836 }
1838 }
1842 {
1845 }
1856 val = iterative_hash_template_arg
1868 val);
1870 val);
1879 /* [temp.over.link] Two lambda-expressions are never considered
1880 equivalent.
1882 So just hash the closure type. */
1893 /* Now hash operands as usual. */
1897 {
1900 {
1904 }
1906 call_expr_arg_iterator ai;
1911 }
1915 }
1919 {
1922 {
1923 // We want an alias specialization that survived strip_typedefs
1924 // to hash differently from its TYPE_CANONICAL, to avoid hash
1925 // collisions that compare as different in template_args_equal.
1926 // These could be dependent specializations that strip_typedefs
1927 // left alone, or untouched specializations because
1928 // coerce_template_parms returns the unconverted template
1929 // arguments if it sees incomplete argument packs.
1932 }
1935 {
1937 {
1940 /* Do not recurse with TPI directly, as that is unbounded
1941 recursion. */
1944 }
1955 }
1968 }
1972 }
1974 /* Unregister the specialization SPEC as a specialization of TMPL.
1975 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1976 if the SPEC was listed as a specialization of TMPL.
1978 Note that SPEC has been ggc_freed, so we can't look inside it. */
1980 bool
1982 {
1984 spec_entry elt;
1992 {
1997 }
2000 }
2002 /* Like register_specialization, but for local declarations. We are
2003 registering SPEC, an instantiation of TMPL. */
2005 void
2007 {
2010 }
2012 /* TYPE is a class type. Returns true if TYPE is an explicitly
2013 specialized class. */
2015 bool
2017 {
2021 }
2023 /* Print the list of functions at FNS, going through all the overloads
2024 for each element of the list. Alternatively, FNS cannot be a
2025 TREE_LIST, in which case it will be printed together with all the
2026 overloads.
2028 MORE and *STR should respectively be FALSE and NULL when the function
2029 is called from the outside. They are used internally on recursive
2030 calls. print_candidates manages the two parameters and leaves NULL
2031 in *STR when it ends. */
2033 static void
2035 {
2039 else
2041 {
2047 {
2050 else
2053 }
2055 }
2056 }
2058 /* Print the list of candidate FNS in an error message. FNS can also
2059 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
2061 void
2063 {
2067 }
2069 /* Get a (possibly) constrained template declaration for the
2070 purpose of ordering candidates. */
2071 static tree
2073 {
2079 }
2081 /* Among candidates having the same signature, return the
2082 most constrained or NULL_TREE if there is no best candidate.
2083 If the signatures of candidates vary (e.g., template
2084 specialization vs. member function), then there can be no
2085 most constrained.
2087 Note that we don't compare constraints on the functions
2088 themselves, but rather those of their templates. */
2089 static tree
2091 {
2092 // Try to find the best candidate in a first pass.
2095 {
2102 }
2104 // Verify that the champ is better than previous candidates.
2109 }
2112 }
2115 /* Returns the template (one of the functions given by TEMPLATE_ID)
2116 which can be specialized to match the indicated DECL with the
2117 explicit template args given in TEMPLATE_ID. The DECL may be
2118 NULL_TREE if none is available. In that case, the functions in
2119 TEMPLATE_ID are non-members.
2121 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2122 specialization of a member template.
2124 The TEMPLATE_COUNT is the number of references to qualifying
2125 template classes that appeared in the name of the function. See
2126 check_explicit_specialization for a more accurate description.
2128 TSK indicates what kind of template declaration (if any) is being
2129 declared. TSK_TEMPLATE indicates that the declaration given by
2130 DECL, though a FUNCTION_DECL, has template parameters, and is
2131 therefore a template function.
2133 The template args (those explicitly specified and those deduced)
2134 are output in a newly created vector *TARGS_OUT.
2136 If it is impossible to determine the result, an error message is
2137 issued. The error_mark_node is returned to indicate failure. */
2139 static tree
2141 tree decl,
2145 tmpl_spec_kind tsk)
2146 {
2147 tree fns;
2148 tree targs;
2149 tree explicit_targs;
2152 /* A TREE_LIST of templates of which DECL may be a specialization.
2153 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2154 corresponding TREE_PURPOSE is the set of template arguments that,
2155 when used to instantiate the template, would produce a function
2156 with the signature of DECL. */
2166 /* We shouldn't be specializing a member template of an
2167 unspecialized class template; we already gave an error in
2168 check_specialization_scope, now avoid crashing. */
2172 {
2175 }
2183 /* Check for baselinks. */
2188 {
2192 }
2194 {
2197 }
2199 /* Count the number of template headers specified for this
2200 specialization. */
2211 {
2214 tf_warning_or_error,
2218 }
2220 {
2224 {
2225 tree decl_arg_types;
2226 tree fn_arg_types;
2227 tree insttype;
2229 /* In case of explicit specialization, we need to check if
2230 the number of template headers appearing in the specialization
2231 is correct. This is usually done in check_explicit_specialization,
2232 but the check done there cannot be exhaustive when specializing
2233 member functions. Consider the following code:
2235 template <> void A<int>::f(int);
2236 template <> template <> void A<int>::f(int);
2238 Assuming that A<int> is not itself an explicit specialization
2239 already, the first line specializes "f" which is a non-template
2240 member function, whilst the second line specializes "f" which
2241 is a template member function. So both lines are syntactically
2242 correct, and check_explicit_specialization does not reject
2243 them.
2245 Here, we can do better, as we are matching the specialization
2246 against the declarations. We count the number of template
2247 headers, and we check if they match TEMPLATE_COUNT + 1
2248 (TEMPLATE_COUNT is the number of qualifying template classes,
2249 plus there must be another header for the member template
2250 itself).
2252 Notice that if header_count is zero, this is not a
2253 specialization but rather a template instantiation, so there
2254 is no check we can perform here. */
2256 {
2259 }
2261 /* Check that the number of template arguments at the
2262 innermost level for DECL is the same as for FN. */
2270 /* DECL might be a specialization of FN. */
2274 /* For a non-static member function, we need to make sure
2275 that the const qualification is the same. Since
2276 get_bindings does not try to merge the "this" parameter,
2277 we must do the comparison explicitly. */
2279 {
2284 /* And the ref-qualification. */
2288 }
2290 /* Skip the "this" parameter and, for constructors of
2291 classes with virtual bases, the VTT parameter. A
2292 full specialization of a constructor will have a VTT
2293 parameter, but a template never will. */
2294 decl_arg_types
2296 fn_arg_types
2299 /* Function templates cannot be specializations; there are
2300 no partial specializations of functions. Therefore, if
2301 the type of DECL does not match FN, there is no
2302 match.
2304 Note that it should never be the case that we have both
2305 candidates added here, and for regular member functions
2306 below. */
2308 {
2310 current_template_parms))
2323 {
2329 }
2333 }
2335 /* See whether this function might be a specialization of this
2336 template. Suppress access control because we might be trying
2337 to make this specialization a friend, and we have already done
2338 access control for the declaration of the specialization. */
2344 /* We cannot deduce template arguments that when used to
2345 specialize TMPL will produce DECL. */
2349 /* We deduced something involving 'auto', which isn't a valid
2350 template argument. */
2353 /* Remove, from the set of candidates, all those functions
2354 whose constraints are not satisfied. */
2358 // Then, try to form the new function type.
2362 fn_arg_types
2367 /* Save this template, and the arguments deduced. */
2369 }
2371 /* FN is an ordinary member function, and we need a
2372 specialization of a member template. */
2373 ;
2375 /* We can get IDENTIFIER_NODEs here in certain erroneous
2376 cases. */
2377 ;
2379 /* This is just an ordinary non-member function. Nothing can
2380 be a specialization of that. */
2381 ;
2383 /* Cannot specialize functions that are created implicitly. */
2384 ;
2385 else
2386 {
2387 tree decl_arg_types;
2389 /* This is an ordinary member function. However, since
2390 we're here, we can assume its enclosing class is a
2391 template class. For example,
2393 template <typename T> struct S { void f(); };
2394 template <> void S<int>::f() {}
2396 Here, S<int>::f is a non-template, but S<int> is a
2397 template class. If FN has the same type as DECL, we
2398 might be in business. */
2401 /* Its enclosing class is an explicit specialization
2402 of a template class. This is not a candidate. */
2407 /* The return types differ. */
2410 /* Adjust the type of DECL in case FN is a static member. */
2417 decl_arg_types))
2425 // If the deduced arguments do not satisfy the constraints,
2426 // this is not a candidate.
2430 // Add the candidate.
2432 }
2433 }
2436 {
2437 /* We have:
2439 [temp.expl.spec]
2441 It is possible for a specialization with a given function
2442 signature to be instantiated from more than one function
2443 template. In such cases, explicit specification of the
2444 template arguments must be used to uniquely identify the
2445 function template specialization being specialized.
2447 Note that here, there's no suggestion that we're supposed to
2448 determine which of the candidate templates is most
2449 specialized. However, we, also have:
2451 [temp.func.order]
2453 Partial ordering of overloaded function template
2454 declarations is used in the following contexts to select
2455 the function template to which a function template
2456 specialization refers:
2458 -- when an explicit specialization refers to a function
2459 template.
2461 So, we do use the partial ordering rules, at least for now.
2462 This extension can only serve to make invalid programs valid,
2463 so it's safe. And, there is strong anecdotal evidence that
2464 the committee intended the partial ordering rules to apply;
2465 the EDG front end has that behavior, and John Spicer claims
2466 that the committee simply forgot to delete the wording in
2467 [temp.expl.spec]. */
2470 {
2473 }
2474 }
2476 // Concepts allows multiple declarations of member functions
2477 // with the same signature. Like above, we need to rely on
2478 // on the partial ordering of those candidates to determine which
2479 // is the best.
2481 {
2483 {
2486 }
2487 }
2490 {
2495 "saw %d %<template<>%>, need %d for "
2500 }
2504 {
2510 }
2512 /* We have one, and exactly one, match. */
2514 {
2518 /* Propagate the candidate's constraints to the declaration. */
2522 /* DECL is a re-declaration or partial instantiation of a template
2523 function. */
2526 /* It was a specialization of an ordinary member function in a
2527 template class. */
2529 }
2531 /* It was a specialization of a template. */
2534 {
2539 }
2540 else
2543 }
2545 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2546 but with the default argument values filled in from those in the
2547 TMPL_TYPES. */
2549 static tree
2551 tree tmpl_types)
2552 {
2553 tree new_spec_types;
2561 /* Substitute into the rest of the list. */
2562 new_spec_types =
2566 /* Add the default argument for this parameter. */
2569 new_spec_types);
2570 }
2572 /* DECL is an explicit specialization. Replicate default arguments
2573 from the template it specializes. (That way, code like:
2575 template <class T> void f(T = 3);
2576 template <> void f(double);
2577 void g () { f (); }
2579 works, as required.) An alternative approach would be to look up
2580 the correct default arguments at the call-site, but this approach
2581 is consistent with how implicit instantiations are handled. */
2583 static void
2585 {
2586 tree tmpl;
2587 tree spec_types;
2588 tree tmpl_types;
2589 tree new_spec_types;
2590 tree old_type;
2591 tree new_type;
2592 tree t;
2597 /* See if there's anything we need to do. */
2610 {
2611 /* Remove the this pointer, but remember the object's type for
2612 CV quals. */
2618 {
2619 /* DECL may contain more parameters than TMPL due to the extra
2620 in-charge parameter in constructors and destructors. */
2623 }
2625 {
2628 }
2629 }
2631 /* Compute the merged default arguments. */
2632 new_spec_types =
2635 /* Compute the new FUNCTION_TYPE. */
2637 {
2641 new_spec_types);
2644 /* Put the in-charge parameter back. */
2647 new_spec_types);
2651 new_spec_types);
2652 }
2653 else
2655 new_spec_types);
2661 }
2663 /* Return the number of template headers we expect to see for a definition
2664 or specialization of CTYPE or one of its non-template members. */
2666 int
2668 {
2672 {
2673 /* You're supposed to have one `template <...>' for every
2674 template class, but you don't need one for a full
2675 specialization. For example:
2677 template <class T> struct S{};
2678 template <> struct S<int> { void f(); };
2679 void S<int>::f () {}
2681 is correct; there shouldn't be a `template <>' for the
2682 definition of `S<int>::f'. */
2684 /* If CTYPE does not have template information of any
2685 kind, then it is not a template, nor is it nested
2686 within a template. */
2694 }
2697 }
2699 /* Do a simple sanity check on the template headers that precede the
2700 variable declaration DECL. */
2702 void
2704 {
2709 {
2712 "variable templates only available with "
2715 // Namespace-scope variable templates should have a template header.
2717 }
2719 {
2720 auto_diagnostic_group d;
2722 "too many template headers for %qD "
2728 "members of an explicitly specialized class are defined "
2730 }
2731 }
2733 /* An explicit specialization whose declarator-id or class-head-name is not
2734 qualified shall be declared in the nearest enclosing namespace of the
2735 template, or, if the namespace is inline (7.3.1), any namespace from its
2736 enclosing namespace set.
2738 If the name declared in the explicit instantiation is an unqualified name,
2739 the explicit instantiation shall appear in the namespace where its template
2740 is declared or, if that namespace is inline (7.3.1), any namespace from its
2741 enclosing namespace set. */
2743 void
2745 {
2750 {
2756 /* This was allowed in C++98, so only pedwarn. */
2758 "outside its namespace must use a nested-name-"
2760 }
2761 }
2763 /* Warn for a template specialization SPEC that is missing some of a set
2764 of function or type attributes that the template TEMPL is declared with.
2765 ATTRLIST is a list of additional attributes that SPEC should be taken
2766 to ultimately be declared with. */
2768 static void
2770 {
2774 /* Avoid warning if the difference between the primary and
2775 the specialization is not in one of the attributes below. */
2779 };
2781 /* Put together a list of the black listed attributes that the primary
2782 template is declared with that the specialization is not, in case
2783 it's not apparent from the most recent declaration of the primary. */
2784 pretty_printer str;
2791 auto_diagnostic_group d;
2794 spec))
2800 }
2802 /* Check to see if the function just declared, as indicated in
2803 DECLARATOR, and in DECL, is a specialization of a function
2804 template. We may also discover that the declaration is an explicit
2805 instantiation at this point.
2807 Returns DECL, or an equivalent declaration that should be used
2808 instead if all goes well. Issues an error message if something is
2809 amiss. Returns error_mark_node if the error is not easily
2810 recoverable.
2812 FLAGS is a bitmask consisting of the following flags:
2814 2: The function has a definition.
2815 4: The function is a friend.
2817 The TEMPLATE_COUNT is the number of references to qualifying
2818 template classes that appeared in the name of the function. For
2819 example, in
2821 template <class T> struct S { void f(); };
2822 void S<int>::f();
2824 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2825 classes are not counted in the TEMPLATE_COUNT, so that in
2827 template <class T> struct S {};
2828 template <> struct S<int> { void f(); }
2829 template <> void S<int>::f();
2831 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2832 invalid; there should be no template <>.)
2834 If the function is a specialization, it is marked as such via
2835 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2836 is set up correctly, and it is added to the list of specializations
2837 for that template. */
2839 tree
2841 tree decl,
2844 tree attrlist)
2845 {
2854 tmpl_spec_kind tsk;
2857 {
2860 else
2862 }
2863 else
2867 {
2870 {
2873 }
2875 {
2877 /* This could be something like:
2879 template <class T> void f(T);
2880 class S { friend void f<>(int); } */
2882 else
2883 {
2884 /* This case handles bogus declarations like template <>
2885 template <class T> void f<int>(); */
2889 declarator);
2891 }
2892 }
2896 /* The error has already been reported in
2897 check_specialization_scope. */
2903 /* Fall through. */
2916 decl);
2919 else
2923 /* Fall through. */
2929 /* In cases like template<> constexpr bool v = true;
2930 We'll give an error in check_template_variable. */
2936 else
2942 {
2943 /* This case handles bogus declarations like template <>
2944 template <class T> void f<int>(); */
2949 declarator);
2951 {
2952 /* Partial specialization of variable template. */
2956 }
2959 "non-type partial specialization %qE "
2961 else
2963 "non-class, non-variable partial specialization %qE "
2966 ok:;
2967 }
2970 /* This is a specialization of a member template, without
2971 specialization the containing class. Something like:
2973 template <class T> struct S {
2974 template <class U> void f (U);
2975 };
2976 template <> template <class U> void S<int>::f(U) {}
2978 That's a specialization -- but of the entire template. */
2984 }
2987 /* This doesn't apply to variable templates. */
2989 {
2993 {
2997 }
2998 }
3001 {
3007 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
3009 {
3010 tree fns;
3015 else
3016 {
3017 /* If there is no class context, the explicit instantiation
3018 must be at namespace scope. */
3021 /* Find the namespace binding, using the declaration
3022 context. */
3026 {
3027 /* If lookup fails, look for a friend declaration so we can
3028 give a better diagnostic. */
3029 fns = (lookup_qualified_name
3034 }
3037 {
3040 }
3041 }
3044 }
3050 {
3052 /* A specialization in class scope. This is invalid,
3053 but the error will already have been flagged by
3054 check_specialization_scope. */
3056 else
3057 {
3058 /* It's not valid to write an explicit instantiation in
3059 class scope, e.g.:
3061 class C { template void f(); }
3063 This case is caught by the parser. However, on
3064 something like:
3066 template class C { void f(); };
3068 (which is invalid) we can get here. The error will be
3069 issued later. */
3070 ;
3071 }
3074 }
3077 {
3078 // We'll match variable templates in start_decl.
3082 /* Find the list of functions in ctype that have the same
3083 name as the declared function. */
3087 {
3091 {
3092 /* From [temp.expl.spec]:
3094 If such an explicit specialization for the member
3095 of a class template names an implicitly-declared
3096 special member function (clause _special_), the
3097 program is ill-formed.
3099 Similar language is found in [temp.explicit]. */
3102 }
3105 }
3107 /* For a type-conversion operator, We might be looking for
3108 `operator int' which will be a specialization of
3109 `operator T'. Grab all the conversion operators, and
3110 then select from them. */
3115 {
3118 }
3119 else
3121 }
3123 /* Figure out what exactly is being specialized at this point.
3124 Note that for an explicit instantiation, even one for a
3125 member function, we cannot tell a priori whether the
3126 instantiation is for a member template, or just a member
3127 function of a template class. Even if a member template is
3128 being instantiated, the member template arguments may be
3129 elided if they can be deduced from the rest of the
3130 declaration. */
3133 member_specialization,
3134 template_count,
3135 tsk);
3138 /* We couldn't figure out what this declaration was
3139 specializing. */
3141 else
3142 {
3144 {
3145 auto_diagnostic_group d;
3147 "friend declaration %qD is not visible to "
3151 }
3160 {
3161 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3162 is done by do_decl_instantiation later. */
3168 {
3169 /* If TMPL is not the most general template (for
3170 example, if TMPL is a friend template that is
3171 injected into namespace scope), then there will
3172 be too many levels of TARGS. Remove some of them
3173 here. */
3175 tree new_targs;
3182 }
3185 }
3187 /* If we thought that the DECL was a member function, but it
3188 turns out to be specializing a static member function,
3189 make DECL a static member function as well. */
3195 /* If this is a specialization of a member template of a
3196 template class, we want to return the TEMPLATE_DECL, not
3197 the specialization of it. */
3199 {
3204 {
3205 tree parm;
3209 /* We want to use the argument list specified in the
3210 definition, not in the original declaration. */
3215 }
3218 }
3220 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3226 /* Inherit default function arguments from the template
3227 DECL is specializing. */
3231 /* This specialization has the same protection as the
3232 template it specializes. */
3236 /* 7.1.1-1 [dcl.stc]
3238 A storage-class-specifier shall not be specified in an
3239 explicit specialization...
3241 The parser rejects these, so unless action is taken here,
3242 explicit function specializations will always appear with
3243 global linkage.
3245 The action recommended by the C++ CWG in response to C++
3246 defect report 605 is to make the storage class and linkage
3247 of the explicit specialization match the templated function:
3249 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3250 */
3252 {
3256 /* A concept cannot be specialized. */
3258 {
3260 gen_tmpl);
3262 }
3264 /* This specialization has the same linkage and visibility as
3265 the function template it specializes. */
3268 {
3271 }
3274 {
3277 }
3278 }
3280 /* If DECL is a friend declaration, declared using an
3281 unqualified name, the namespace associated with DECL may
3282 have been set incorrectly. For example, in:
3284 template <typename T> void f(T);
3285 namespace N {
3286 struct S { friend void f<int>(int); }
3287 }
3289 we will have set the DECL_CONTEXT for the friend
3290 declaration to N, rather than to the global namespace. */
3295 /* This is not really a declaration of a specialization.
3296 It's just the name of an instantiation. But, it's not
3297 a request for an instantiation, either. */
3300 /* A specialization is not necessarily COMDAT. */
3306 /* If this is a full specialization, register it so that we can find
3307 it again. Partial specializations will be registered in
3308 process_partial_specialization. */
3310 {
3315 }
3318 /* A 'structor should already have clones. */
3324 }
3325 }
3328 }
3330 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3331 parameters. These are represented in the same format used for
3332 DECL_TEMPLATE_PARMS. */
3334 int
3336 {
3337 const_tree p1;
3338 const_tree p2;
3346 {
3358 {
3362 /* If either of the template parameters are invalid, assume
3363 they match for the sake of error recovery. */
3376 }
3377 }
3380 /* One set of parameters has more parameters lists than the
3381 other. */
3385 }
3387 /* Returns true if two template parameters are declared with
3388 equivalent constraints. */
3390 static bool
3392 {
3400 }
3402 /* Returns true when two template parameters are equivalent. */
3404 static bool
3406 {
3410 /* If either of the template parameters are invalid, assume
3411 they match for the sake of error recovery. */
3415 /* ... they declare parameters of the same kind. */
3419 /* ... one parameter was introduced by a parameter declaration, then
3420 both are. This case arises as a result of eagerly rewriting declarations
3421 during parsing. */
3425 /* ... if either declares a pack, they both do. */
3430 {
3431 /* ... if they declare non-type parameters, the types are equivalent. */
3434 }
3436 {
3437 /* ... if they declare template template parameters, their template
3438 parameter lists are equivalent. */
3441 }
3443 /* ... if they are declared with a qualified-concept name, they both
3444 are, and those names are equivalent. */
3446 }
3448 /* Returns true if two template parameters lists are equivalent.
3449 Two template parameter lists are equivalent if they have the
3450 same length and their corresponding parameters are equivalent.
3452 PARMS1 and PARMS2 are TREE_LISTs containing TREE_VECs: the
3453 data structure returned by DECL_TEMPLATE_PARMS.
3455 This is generally the same implementation as comp_template_parms
3456 except that it also the concept names and arguments used to
3457 introduce parameters. */
3459 static bool
3461 {
3468 {
3476 {
3481 }
3485 }
3491 }
3493 /* Return true if the requires-clause of the template parameter lists are
3494 equivalent and false otherwise. */
3495 static bool
3497 {
3505 }
3507 /* Returns true if two template heads are equivalent. 17.6.6.1p6:
3508 Two template heads are equivalent if their template parameter
3509 lists are equivalent and their requires clauses are equivalent.
3511 In pre-C++20, this is equivalent to calling comp_template_parms
3512 for the template parameters of TMPL1 and TMPL2. */
3514 bool
3516 {
3520 /* Don't change the matching rules for pre-C++20. */
3524 /* ... have the same number of template parameters, and their
3525 corresponding parameters are equivalent. */
3529 /* ... if either has a requires-clause, they both do and their
3530 corresponding constraint-expressions are equivalent. */
3532 }
3534 /* Determine whether PARM is a parameter pack. */
3536 bool
3538 {
3539 /* Determine if we have a non-type template parameter pack. */
3546 /* If this is a list of template parameters, we could get a
3547 TYPE_DECL or a TEMPLATE_DECL. */
3551 /* Otherwise it must be a type template parameter. */
3555 }
3557 /* Determine if T is a function parameter pack. */
3559 bool
3561 {
3565 }
3567 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3568 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3570 tree
3572 {
3579 }
3581 /* Return true iff the function parameter PARAM_DECL was expanded
3582 from the function parameter pack PACK. */
3584 bool
3586 {
3591 /* The parameter pack and its pack arguments have the same
3592 DECL_PARM_INDEX. */
3594 }
3596 /* Determine whether ARGS describes a variadic template args list,
3597 i.e., one that is terminated by a template argument pack. */
3599 static bool
3601 {
3603 tree last_parm;
3617 }
3619 /* Generate a new name for the parameter pack name NAME (an
3620 IDENTIFIER_NODE) that incorporates its */
3622 static tree
3624 {
3625 /* Munge the name to include the parameter index. */
3626 #define NUMBUF_LEN 128
3640 }
3642 /* Return true if T is a primary function, class or alias template
3643 specialization, not including the template pattern. */
3645 bool
3647 {
3663 }
3665 /* Return true if PARM is a template template parameter. */
3667 bool
3669 {
3671 }
3673 /* Return true iff PARM is a DECL representing a type template
3674 parameter. */
3676 bool
3678 {
3683 }
3685 /* Return the template parameters of T if T is a
3686 primary template instantiation, NULL otherwise. */
3688 tree
3690 {
3695 parms = INNERMOST_TEMPLATE_PARMS
3699 }
3701 /* Returns the template arguments of T if T is a template instantiation,
3702 NULL otherwise. */
3704 tree
3706 {
3714 }
3716 /* Return the argument pack elements of T if T is a template argument pack,
3717 NULL otherwise. */
3719 tree
3721 {
3727 }
3729 /* In an ARGUMENT_PACK_SELECT, the actual underlying argument that the
3730 ARGUMENT_PACK_SELECT represents. */
3732 static tree
3734 {
3738 /* If the selected argument is an expansion E, that most likely means we were
3739 called from gen_elem_of_pack_expansion_instantiation during the
3740 substituting of an argument pack (of which the Ith element is a pack
3741 expansion, where I is ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
3742 In this case, the Ith element resulting from this substituting is going to
3743 be a pack expansion, which pattern is the pattern of E. Let's return the
3744 pattern of E, and gen_elem_of_pack_expansion_instantiation will build the
3745 resulting pack expansion from it. */
3747 {
3748 /* Make sure we aren't throwing away arg info. */
3751 }
3754 }
3757 /* True iff FN is a function representing a built-in variadic parameter
3758 pack. */
3760 bool
3762 {
3772 }
3774 /* True iff CALL is a call to a function representing a built-in variadic
3775 parameter pack. */
3777 static bool
3779 {
3783 }
3785 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3787 static tree
3789 tree in_decl)
3790 {
3796 {
3798 {
3801 }
3806 }
3807 else
3808 {
3812 /* Calculate the largest value of len that won't make the size of the vec
3813 overflow an int. The compiler will exceed resource limits long before
3814 this, but it seems a decent place to diagnose. */
3818 {
3822 max);
3824 }
3832 }
3833 }
3835 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3836 CALL. */
3838 static tree
3840 tree in_decl)
3841 {
3851 }
3853 /* Structure used to track the progress of find_parameter_packs_r. */
3854 struct find_parameter_pack_data
3855 {
3856 /* TREE_LIST that will contain all of the parameter packs found by
3857 the traversal. */
3860 /* Set of AST nodes that have been visited by the traversal. */
3863 /* True iff we're making a type pack expansion. */
3865 };
3867 /* Identifies all of the argument packs that occur in a template
3868 argument and appends them to the TREE_LIST inside DATA, which is a
3869 find_parameter_pack_data structure. This is a subroutine of
3870 make_pack_expansion and uses_parameter_packs. */
3871 static tree
3873 {
3879 #define WALK_SUBTREE(NODE) \
3880 cp_walk_tree (&(NODE), &find_parameter_packs_r, \
3881 ppd, ppd->visited) \
3883 /* Don't look through typedefs; we are interested in whether a
3884 parameter pack is actually written in the expression/type we're
3885 looking at, not the target type. */
3887 {
3888 /* But do look at arguments for an alias template. */
3895 }
3897 /* Identify whether this is a parameter pack or not. */
3899 {
3907 /* FALLTHRU */
3909 /* If the placeholder appears in the decl-specifier-seq of a function
3910 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3911 is a pack expansion, the invented template parameter is a template
3912 parameter pack. */
3922 {
3923 /* We don't want to walk into the type of a PARM_DECL,
3924 because we don't want to see the type parameter pack. */
3927 }
3932 {
3933 /* We don't want to walk into the type of a variadic capture proxy,
3934 because we don't want to see the type parameter pack. */
3937 }
3939 {
3941 find_parameter_packs_r,
3944 }
3956 /* Not a parameter pack. */
3958 }
3961 {
3962 /* Add this parameter pack to the list. */
3964 }
3970 /* This switch statement will return immediately if we don't find a
3971 parameter pack. ??? Should some of these be in cp_walk_subtrees? */
3973 {
3975 /* Check the template itself. */
3981 {
3983 /* Ignore the declaration of a capture proxy for a parameter pack. */
3987 /* Since we stop at typedefs above, we need to look through them at
3988 the point of the DECL_EXPR. */
3992 }
4019 {
4020 /* Since we defer implicit capture, look in the parms and body. */
4027 }
4030 {
4031 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
4032 type_pack_expansion_p to false so that any placeholders
4033 within the expression don't get marked as parameter packs. */
4041 }
4050 /* Don't walk into IF_STMT_EXTRA_ARGS. */
4057 /* Local class, need to look through the whole definition. */
4061 else
4062 /* Enum, look at the values. */
4076 }
4078 #undef WALK_SUBTREE
4081 }
4083 /* Determines if the expression or type T uses any parameter packs. */
4084 tree
4086 {
4095 }
4097 /* Turn ARG, which may be an expression, type, or a TREE_LIST
4098 representation a base-class initializer into a parameter pack
4099 expansion. If all goes well, the resulting node will be an
4100 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
4101 respectively. */
4102 tree
4104 {
4105 tree result;
4114 {
4115 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
4116 class initializer. In this case, the TREE_PURPOSE will be a
4117 _TYPE node (representing the base class expansion we're
4118 initializing) and the TREE_VALUE will be a TREE_LIST
4119 containing the initialization arguments.
4121 The resulting expansion looks somewhat different from most
4122 expansions. Rather than returning just one _EXPANSION, we
4123 return a TREE_LIST whose TREE_PURPOSE is a
4124 TYPE_PACK_EXPANSION containing the bases that will be
4125 initialized. The TREE_VALUE will be identical to the
4126 original TREE_VALUE, which is a list of arguments that will
4127 be passed to each base. We do not introduce any new pack
4128 expansion nodes into the TREE_VALUE (although it is possible
4129 that some already exist), because the TREE_PURPOSE and
4130 TREE_VALUE all need to be expanded together with the same
4131 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
4132 resulting TREE_PURPOSE will mention the parameter packs in
4133 both the bases and the arguments to the bases. */
4134 tree purpose;
4135 tree value;
4138 /* Determine which parameter packs will be used by the base
4139 class expansion. */
4148 {
4151 arg);
4154 }
4157 {
4158 /* Collect the sets of parameter packs used in each of the
4159 initialization arguments. */
4161 {
4162 /* Determine which parameter packs will be expanded in this
4163 argument. */
4166 }
4167 }
4171 /* Create the pack expansion type for the base type. */
4177 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4178 they will rarely be compared to anything. */
4182 }
4187 /* Build the PACK_EXPANSION_* node. */
4188 result = for_types
4193 {
4194 /* Propagate type and const-expression information. */
4197 /* Mark this read now, since the expansion might be length 0. */
4199 }
4200 else
4201 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4202 they will rarely be compared to anything. */
4205 /* Determine which parameter packs will be expanded. */
4212 /* Make sure we found some parameter packs. */
4214 {
4216 {
4219 else
4221 }
4223 }
4229 }
4231 /* Checks T for any "bare" parameter packs, which have not yet been
4232 expanded, and issues an error if any are found. This operation can
4233 only be done on full expressions or types (e.g., an expression
4234 statement, "if" condition, etc.), because we could have expressions like:
4236 foo(f(g(h(args)))...)
4238 where "args" is a parameter pack. check_for_bare_parameter_packs
4239 should not be called for the subexpressions args, h(args),
4240 g(h(args)), or f(g(h(args))), because we would produce erroneous
4241 error messages.
4243 Returns TRUE and emits an error if there were bare parameter packs,
4244 returns FALSE otherwise. */
4245 bool
4247 {
4263 /* It's OK for a lambda to have an unexpanded parameter pack from the
4264 containing context, but do complain about unexpanded capture packs. */
4269 {
4273 }
4276 {
4281 {
4292 else
4297 else
4301 }
4304 }
4307 }
4309 /* Expand any parameter packs that occur in the template arguments in
4310 ARGS. */
4311 tree
4313 {
4322 /* First, determine if we need to expand anything, and the number of
4323 slots we'll need. */
4325 {
4330 {
4334 else
4336 }
4337 else
4338 {
4340 num_result_args++;
4341 }
4342 }
4344 /* If no expansion is necessary, we're done. */
4348 /* Expand arguments. */
4351 non_default_args_count =
4354 {
4357 {
4364 }
4365 else
4366 {
4369 }
4370 }
4374 }
4376 /* Checks if DECL shadows a template parameter.
4378 [temp.local]: A template-parameter shall not be redeclared within its
4379 scope (including nested scopes).
4381 Emits an error and returns TRUE if the DECL shadows a parameter,
4382 returns FALSE otherwise. */
4384 bool
4386 {
4387 tree olddecl;
4389 /* If we're not in a template, we can't possibly shadow a template
4390 parameter. */
4394 /* Figure out what we're shadowing. */
4398 /* If there's no previous binding for this name, we're not shadowing
4399 anything, let alone a template parameter. */
4403 /* If we're not shadowing a template parameter, we're done. Note
4404 that OLDDECL might be an OVERLOAD (or perhaps even an
4405 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4406 node. */
4410 /* We check for decl != olddecl to avoid bogus errors for using a
4411 name inside a class. We check TPFI to avoid duplicate errors for
4412 inline member templates. */
4418 /* Don't complain about the injected class name, as we've already
4419 complained about the class itself. */
4426 else
4431 }
4433 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4434 ORIG_LEVEL, DECL, and TYPE. */
4436 static tree
4440 tree decl,
4441 tree type)
4442 {
4453 }
4455 /* Find the canonical type parameter for the given template type
4456 parameter. Returns the canonical type parameter, which may be TYPE
4457 if no such parameter existed. */
4459 tree
4461 {
4477 }
4479 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4480 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4481 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4482 new one is created. */
4484 static tree
4486 tsubst_flags_t complain)
4487 {
4492 {
4497 type);
4512 /* Template template parameters need this. */
4515 {
4522 }
4524 /* Attach the TPI to the decl. */
4527 else
4529 }
4532 }
4534 /* Process information from new template parameter PARM and append it
4535 to the LIST being built. This new parameter is a non-type
4536 parameter iff IS_NON_TYPE is true. This new parameter is a
4537 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4538 is in PARM_LOC. */
4540 tree
4543 {
4549 {
4559 }
4566 {
4572 {
4573 /* [temp.param]
4575 The top-level cv-qualifiers on the template-parameter are
4576 ignored when determining its type. */
4581 && !is_parameter_pack
4582 /* If we're in a nested template parameter list, the template
4583 template parameter could be a parameter pack. */
4585 {
4586 /* This template parameter is not a parameter pack, but it
4587 should be. Complain about "bare" parameter packs. */
4590 /* Recover by calling this a parameter pack. */
4592 }
4593 }
4595 /* A template parameter is not modifiable. */
4604 processing_template_decl,
4609 }
4610 else
4611 {
4612 tree t;
4616 {
4618 /* This is for distinguishing between real templates and template
4619 template parameters */
4622 /* any_template_parm_r expects to be able to get the targs of a
4623 DECL_TEMPLATE_RESULT. */
4632 }
4633 else
4634 {
4636 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4639 }
4646 processing_template_decl,
4651 else
4653 }
4657 /* Build requirements for the type/template parameter.
4658 This must be done after SET_DECL_TEMPLATE_PARM_P or
4659 process_template_parm could fail. */
4666 /* Build the parameter node linking the parameter declaration,
4667 its default argument (if any), and its constraints (if any). */
4673 else
4677 }
4679 /* The end of a template parameter list has been reached. Process the
4680 tree list into a parameter vector, converting each parameter into a more
4681 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4682 as PARM_DECLs. */
4684 tree
4686 {
4689 /* Pop the dummy parameter level and add the real one. We do not
4690 morph the dummy parameter in place, as it might have been
4691 captured by a (nested) template-template-parm. */
4694 current_template_parms
4699 {
4705 }
4710 }
4712 // Explicitly indicate the end of the template parameter list. We assume
4713 // that the current template parameters have been constructed and/or
4714 // managed explicitly, as when creating new template template parameters
4715 // from a shorthand constraint.
4716 void
4718 {
4720 }
4722 /* end_template_decl is called after a template declaration is seen. */
4724 void
4726 {
4732 /* This matches the pushlevel in begin_template_parm_list. */
4737 }
4739 /* Takes a TEMPLATE_PARM_P or DECL_TEMPLATE_PARM_P node or a TREE_LIST
4740 thereof, and converts it into an argument suitable to be passed to
4741 the type substitution functions. Note that if the TREE_LIST contains
4742 an error_mark node, the returned argument is error_mark_node. */
4744 tree
4746 {
4757 {
4761 else
4763 }
4769 {
4771 {
4772 /* Turn this argument into a TYPE_ARGUMENT_PACK
4773 with a single element, which expands T. */
4782 }
4783 }
4784 else
4785 {
4787 {
4788 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4789 with a single element, which expands T. */
4799 }
4800 else
4802 }
4804 }
4806 /* Given a single level of template parameters (a TREE_VEC), return it
4807 as a set of template arguments. */
4809 tree
4811 {
4821 }
4823 /* Given a set of template parameters, return them as a set of template
4824 arguments. The template parameters are represented as a TREE_VEC, in
4825 the form documented in cp-tree.h for template arguments. */
4827 tree
4829 {
4830 tree header;
4835 /* If there is only one level of template parameters, we do not
4836 create a TREE_VEC of TREE_VECs. Instead, we return a single
4837 TREE_VEC containing the arguments. */
4842 {
4847 else
4849 }
4852 }
4854 /* Within the declaration of a template, return the currently active
4855 template parameters as an argument TREE_VEC. */
4857 static tree
4859 {
4861 }
4863 /* Return the fully generic arguments for of TMPL, i.e. what
4864 current_template_args would be while parsing it. */
4866 tree
4868 {
4873 /* DECL_TEMPLATE_RESULT doesn't have the arguments we want. For a template
4874 template parameter, it has no TEMPLATE_INFO; for a partial
4875 specialization, it has the arguments for the primary template, and we
4881 }
4883 /* Update the declared TYPE by doing any lookups which were thought to be
4884 dependent, but are not now that we know the SCOPE of the declarator. */
4886 tree
4888 {
4899 /* Don't bother building up the args in this case. */
4901 {
4902 /* tsubst in the args corresponding to the template parameters,
4903 including auto if present. Most things will be unchanged, but
4904 make_typename_type and tsubst_qualified_id will resolve
4905 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4908 tree pushed;
4910 {
4914 }
4919 }
4925 {
4928 else
4930 }
4932 }
4934 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4935 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4936 the new template is a member template. */
4938 static tree
4940 {
4950 /* Propagate module information from the decl. */
4954 }
4956 struct template_parm_data
4957 {
4958 /* The level of the template parameters we are currently
4959 processing. */
4962 /* The index of the specialization argument we are currently
4963 processing. */
4966 /* An array whose size is the number of template parameters. The
4967 elements are nonzero if the parameter has been used in any one
4968 of the arguments processed so far. */
4971 /* An array whose size is the number of template arguments. The
4972 elements are nonzero if the argument makes use of template
4973 parameters of this level. */
4975 };
4977 /* Subroutine of push_template_decl used to see if each template
4978 parameter in a partial specialization is used in the explicit
4979 argument list. If T is of the LEVEL given in DATA (which is
4980 treated as a template_parm_data*), then DATA->PARMS is marked
4981 appropriately. */
4983 static int
4985 {
4993 {
4996 }
4998 /* In C++17 the type of a non-type argument is a deduced context. */
5003 data,
5004 NULL,
5007 /* Return zero so that for_each_template_parm will continue the
5008 traversal of the tree; we want to mark *every* template parm. */
5010 }
5012 /* Process the partial specialization DECL. */
5014 static tree
5016 {
5023 tree inner_parms;
5024 tree inst;
5034 /* A concept cannot be specialized. */
5036 {
5039 }
5044 /* We check that each of the template parameters given in the
5045 partial specialization is used in the argument list to the
5046 specialization. For example:
5048 template <class T> struct S;
5049 template <class T> struct S<T*>;
5051 The second declaration is OK because `T*' uses the template
5052 parameter T, whereas
5054 template <class T> struct S<int>;
5056 is no good. Even trickier is:
5058 template <class T>
5059 struct S1
5060 {
5061 template <class U>
5062 struct S2;
5063 template <class U>
5064 struct S2<T>;
5065 };
5067 The S2<T> declaration is actually invalid; it is a
5068 full-specialization. Of course,
5070 template <class U>
5071 struct S2<T (*)(U)>;
5073 or some such would have been OK. */
5081 {
5086 NULL,
5088 }
5091 {
5092 /* One of the template parms was not used in a deduced context in the
5093 specialization. */
5095 {
5099 }
5103 }
5108 /* [temp.class.spec]
5110 The argument list of the specialization shall not be identical to
5111 the implicit argument list of the primary template. */
5112 tree main_args
5115 && (!flag_concepts
5117 {
5120 "any template arguments; to define the primary template, "
5122 else
5124 "template arguments and is not more constrained than "
5125 "the primary template; to define the primary template, "
5128 }
5130 /* A partial specialization that replaces multiple parameters of the
5131 primary template with a pack expansion is less specialized for those
5132 parameters. */
5134 {
5136 "primary template because it replaces multiple parameters "
5139 /* Avoid crash in process_partial_specialization. */
5141 }
5144 {
5147 /* Avoid crash below. */
5149 }
5151 /* If we aren't in a dependent class, we can actually try deduction. */
5153 /* FIXME we should be able to handle a partial specialization of a
5154 partial instantiation, but currently we can't (c++/41727). */
5157 {
5158 auto_diagnostic_group d;
5162 maintmpl);
5163 }
5165 /* [temp.spec.partial]
5167 The type of a template parameter corresponding to a specialized
5168 non-type argument shall not be dependent on a parameter of the
5169 specialization.
5171 Also, we verify that pack expansions only occur at the
5172 end of the argument list. */
5175 {
5182 {
5183 /* Extract the arguments from the argument pack. We'll be
5184 iterating over these in the following loop. */
5187 }
5190 {
5192 /* Get the Jth argument in the parameter pack. */
5196 {
5197 /* Pack expansions must come at the end of the
5198 argument list. */
5201 {
5205 else
5208 }
5209 }
5212 /* We only care about the pattern. */
5218 /* This next two lines are the `argument expression is not just a
5219 simple identifier' condition and also the `specialized
5220 non-type argument' bit. */
5225 {
5226 /* Look at the corresponding template parameter,
5227 marking which template parameters its type depends
5228 upon. */
5232 {
5233 /* We haven't yet initialized TPD2. Do so now. */
5235 /* The number of parameters here is the number in the
5236 main template, which, as checked in the assertion
5237 above, is NARGS. */
5241 }
5243 /* Mark the template parameters. But this time, we're
5244 looking for the template parameters of the main
5245 template, not in the specialization. */
5252 NULL,
5256 {
5257 /* The type depended on some template parameters.
5258 If they are fully specialized in the
5259 specialization, that's OK. */
5268 "type %qT of template argument %qE depends "
5270 "type %qT of template argument %qE depends "
5272 type,
5273 arg);
5274 }
5275 }
5276 }
5277 }
5279 /* We should only get here once. */
5283 // Build the template decl.
5290 /* Give template template parms a DECL_CONTEXT of the template
5291 for which they are a parameter. */
5293 {
5297 }
5300 /* We didn't register this in check_explicit_specialization so we could
5301 wait until the constraints were set. */
5303 else
5313 {
5319 {
5327 "declaration of %qD ambiguates earlier template "
5331 "partial specialization of %qD after instantiation "
5333 }
5334 }
5337 }
5339 /* PARM is a template parameter of some form; return the corresponding
5340 TEMPLATE_PARM_INDEX. */
5342 static tree
5344 {
5357 }
5359 /* Subroutine of fixed_parameter_pack_p below. Look for any template
5360 parameter packs used by the template parameter PARM. */
5362 static void
5364 {
5365 /* A type parm can't refer to another parm. */
5369 {
5373 }
5379 {
5383 else
5385 }
5386 }
5388 /* PARM is a template parameter pack. Return any parameter packs used in
5389 its type or the type of any of its template parameters. If there are
5390 any such packs, it will be instantiated into a fixed template parameter
5391 list by partial instantiation rather than be fully deduced. */
5393 tree
5395 {
5396 /* This can only be true in a member template. */
5399 /* This can only be true for a parameter pack. */
5402 /* A type parm can't refer to another parm. */
5416 }
5418 /* Check that a template declaration's use of default arguments and
5419 parameter packs is not invalid. Here, PARMS are the template
5420 parameters. IS_PRIMARY is true if DECL is the thing declared by
5421 a primary template. IS_PARTIAL is true if DECL is a partial
5422 specialization.
5424 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
5425 function template declaration or a friend class template
5426 declaration. In the function case, 1 indicates a declaration, 2
5427 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
5428 emitted for extraneous default arguments.
5430 Returns TRUE if there were no errors found, FALSE otherwise. */
5432 bool
5435 {
5438 tree parm_level;
5441 /* [temp.param]
5443 A default template-argument shall not be specified in a
5444 function template declaration or a function template definition, nor
5445 in the template-parameter-list of the definition of a member of a
5446 class template. */
5450 /* You can't have a function template declaration in a local
5451 scope, nor you can you define a member of a class template in a
5452 local scope. */
5460 /* A lambda doesn't have an explicit declaration; don't complain
5461 about the parms of the enclosing class. */
5468 /* If this is either a friend defined in the scope of the class
5469 or a member function. */
5475 /* And, if it was a member function, it really was defined in
5476 the scope of the class. */
5479 /* We already checked these parameters when the template was
5480 declared, so there's no need to do it again now. This function
5481 was defined in class scope, but we're processing its body now
5482 that the class is complete. */
5485 /* Core issue 226 (C++0x only): the following only applies to class
5486 templates. */
5489 {
5490 /* [temp.param]
5492 If a template-parameter has a default template-argument, all
5493 subsequent template-parameters shall have a default
5494 template-argument supplied. */
5496 {
5503 {
5513 {
5515 /* For better subsequent error-recovery, we indicate that
5516 there should have been a default argument. */
5519 }
5521 && !is_friend_decl
5522 /* Don't complain about an enclosing partial
5523 specialization. */
5528 /* A fixed parameter pack will be partially
5529 instantiated into a fixed length list. */
5531 {
5532 /* A primary class template, primary variable template
5533 (DR 2032), or alias template can only have one
5534 parameter pack, at the end of the template
5535 parameter list. */
5543 }
5544 }
5545 }
5546 }
5549 || is_partial
5550 || !is_primary
5552 /* For an ordinary class template, default template arguments are
5553 allowed at the innermost level, e.g.:
5554 template <class T = int>
5555 struct S {};
5556 but, in a partial specialization, they're not allowed even
5557 there, as we have in [temp.class.spec]:
5559 The template parameter list of a specialization shall not
5560 contain default template argument values.
5562 So, for a partial specialization, or for a function template
5563 (in C++98/C++03), we look at all of them. */
5564 ;
5565 else
5566 /* But, for a primary class template that is not a partial
5567 specialization we look at all template parameters except the
5568 innermost ones. */
5571 /* Figure out what error message to issue. */
5586 else
5587 /* Per [temp.param]/9, "A default template-argument shall not be
5588 specified in the template-parameter-lists of the definition of
5589 a member of a class template that appears outside of the member's
5590 class.", thus if we aren't handling a member of a class template
5591 there is no need to examine the parameters. */
5595 /* If we're inside a class definition, there's no need to
5596 examine the parameters to the class itself. On the one
5597 hand, they will be checked when the class is defined, and,
5598 on the other, default arguments are valid in things like:
5599 template <class T = double>
5600 struct S { template <class U> void f(U); };
5601 Here the default argument for `S' has no bearing on the
5602 declaration of `f'. */
5604 else
5605 /* Check everything. */
5611 {
5618 {
5623 {
5625 {
5632 }
5634 /* Clear out the default argument so that we are not
5635 confused later. */
5637 }
5638 }
5640 /* At this point, if we're still interested in issuing messages,
5641 they must apply to classes surrounding the object declared. */
5645 }
5648 }
5650 /* Worker for push_template_decl_real, called via
5651 for_each_template_parm. DATA is really an int, indicating the
5652 level of the parameters we are interested in. If T is a template
5653 parameter of that level, return nonzero. */
5655 static int
5657 {
5663 else
5666 }
5668 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5669 DATA is really an int, indicating the innermost outer level of parameters.
5670 If T is a template parameter of that level or further out, return
5671 nonzero. */
5673 static int
5675 {
5681 else
5684 }
5686 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5687 parameters given by current_template_args, or reuses a
5688 previously existing one, if appropriate. Returns the DECL, or an
5689 equivalent one, if it is replaced via a call to duplicate_decls.
5691 If IS_FRIEND is true, DECL is a friend declaration. */
5693 tree
5695 {
5699 /* See if this is a partial specialization. */
5708 /* No surprising friend functions. */
5713 tree ctx;
5715 /* For a friend, we want the context of the friend, not
5716 the type of which it is a friend. */
5720 /* In the case of a virtual function, we want the class in which
5721 it is defined. */
5723 else
5724 /* Otherwise, if we're currently defining some class, the DECL
5725 is assumed to be a member of the class. */
5734 /* See if this is a primary template. */
5738 /* A friend template that specifies a class context, i.e.
5739 template <typename T> friend void A<T>::f();
5740 is not primary. */
5741 ;
5743 /* Lambdas are not primary. */
5744 ;
5745 else
5748 /* True if the template is a member template, in the sense of
5749 [temp.mem]. */
5753 {
5761 {
5764 }
5766 {
5768 {
5771 }
5773 {
5774 /* [temp.mem]
5776 A destructor shall not be a member template. */
5780 }
5787 {
5788 /* [basic.stc.dynamic.allocation]
5790 An allocation function can be a function
5791 template. ... Template allocation functions shall
5792 have two or more parameters. */
5795 }
5796 }
5799 {
5800 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5803 {
5809 }
5810 }
5813 /* alias-declaration */
5819 else
5820 {
5823 }
5824 }
5831 /* Check to see that the rules regarding the use of default
5832 arguments are not being violated. We check args for a friend
5833 functions when we know whether it's a definition, introducing
5834 declaration or re-declaration. */
5839 /* Ensure that there are no parameter packs in the type of this
5840 declaration that have not been expanded. */
5842 {
5843 /* Check each of the arguments individually to see if there are
5844 any bare parameter packs. */
5850 {
5853 {
5854 /* This is a PARM_DECL that contains unexpanded parameter
5855 packs. We have already complained about this in the
5856 check_for_bare_parameter_packs call, so just replace
5857 these types with ERROR_MARK_NODE. */
5860 }
5864 }
5866 /* Check for bare parameter packs in the return type and the
5867 exception specifiers. */
5869 /* Errors were already issued, set return type to int
5870 as the frontend doesn't expect error_mark_node as
5871 the return type. */
5875 }
5879 {
5882 }
5891 {
5892 /* Does not get a template head. */
5895 }
5902 {
5907 /* If DECL is a TYPE_DECL for a class-template, then there won't
5908 be DECL_LANG_SPECIFIC. The information equivalent to
5909 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5913 {
5914 /* Since a template declaration already existed for this
5915 class-type, we must be redeclaring it here. Make sure
5916 that the redeclaration is valid. */
5918 current_template_parms,
5920 /* We don't need to create a new TEMPLATE_DECL; just use the
5921 one we already had. */
5923 }
5924 else
5925 {
5927 member_template_p);
5932 {
5933 /* A specialization of a member template of a template
5934 class. */
5938 }
5939 }
5940 }
5941 else
5942 {
5948 {
5951 }
5959 {
5960 /* The declaration is a specialization of a member
5961 template, declared outside the class. Therefore, the
5962 innermost template arguments will be NULL, so we
5963 replace them with the arguments determined by the
5964 earlier call to check_explicit_specialization. */
5967 tree new_tmpl
5969 member_template_p);
5977 args,
5980 }
5982 /* Make sure the template headers we got make sense. */
5987 {
5992 }
5993 else
5995 {
6000 {
6004 else
6008 /* Avoid crash in import_export_decl. */
6011 }
6016 /* Can happen in erroneous input. */
6018 else
6020 }
6022 /* Check that the parms are used in the appropriate qualifying scopes
6023 in the declarator. */
6027 {
6033 /* Avoid crash in import_export_decl. */
6036 }
6037 }
6042 {
6043 /* Push template declarations for global functions and types.
6044 Note that we do not try to push a global template friend
6045 declared in a template class; such a thing may well depend on
6046 the template parameters of the class and we'll push it when
6047 instantiating the befriending class. */
6050 {
6055 /* pushdecl may have found an existing template. */
6057 {
6060 }
6061 }
6063 {
6064 /* Record this decl as belonging to the current class. It's
6065 not chained onto anything else. */
6069 }
6070 }
6072 /* The type may have been completed, or (erroneously) changed. */
6076 {
6078 {
6083 /* Give template template parms a DECL_CONTEXT of the template
6084 for which they are a parameter. */
6087 {
6091 }
6095 {
6098 {
6099 /* ??? Why don't we do this here for all templates? */
6102 }
6105 }
6106 }
6108 /* The DECL_TI_ARGS of DECL contains full set of arguments
6109 referring wback to its most general template. If TMPL is a
6110 specialization, ARGS may only have the innermost set of
6111 arguments. Add the missing argument levels if necessary. */
6119 else
6120 {
6123 }
6124 }
6127 && !is_friend
6130 /* Set DECL_COMDAT on template instantiations; if we force
6131 them to be emitted by explicit instantiation,
6132 mark_needed will tell cgraph to do the right thing. */
6138 }
6140 /* FN is an inheriting constructor that inherits from the constructor
6141 template INHERITED; turn FN into a constructor template with a matching
6142 template header. */
6144 tree
6146 {
6147 tree inner_parms
6150 tree parms
6159 }
6161 /* Called when a class template TYPE is redeclared with the indicated
6162 template PARMS, e.g.:
6164 template <class T> struct S;
6165 template <class T> struct S {}; */
6167 bool
6169 {
6170 tree tmpl;
6171 tree tmpl_parms;
6175 {
6178 }
6182 /* The type is nested in some template class. Nothing to worry
6183 about here; there are no new template parameters for the nested
6184 type. */
6188 {
6190 tmpl);
6192 }
6198 {
6208 }
6211 {
6212 tree tmpl_parm;
6213 tree parm;
6214 tree tmpl_default;
6215 tree parm_default;
6229 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
6230 TEMPLATE_DECL. */
6240 {
6241 auto_diagnostic_group d;
6245 }
6247 /* The parameters can be declared to introduce different
6248 constraints. */
6252 {
6253 auto_diagnostic_group d;
6259 }
6262 {
6263 /* We have in [temp.param]:
6265 A template-parameter may not be given default arguments
6266 by two different declarations in the same scope. */
6267 auto_diagnostic_group d;
6272 }
6275 /* Update the previous template parameters (which are the ones
6276 that will really count) with the new default value. */
6279 /* Update the new parameters, too; they'll be used as the
6280 parameters for any members. */
6283 /* Give each template template parm in this redeclaration a
6284 DECL_CONTEXT of the template for which they are a parameter. */
6286 {
6289 }
6293 }
6299 /* Two classes with different constraints declare different entities. */
6301 {
6302 auto_diagnostic_group d;
6308 }
6311 }
6313 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
6314 to be used when the caller has already checked
6315 (processing_template_decl
6316 && !instantiation_dependent_expression_p (expr)
6317 && potential_constant_expression (expr))
6318 and cleared processing_template_decl. */
6320 tree
6322 {
6325 complain,
6329 }
6331 /* Simplify EXPR if it is a non-dependent expression. Returns the
6332 (possibly simplified) expression. */
6334 tree
6336 {
6340 /* If we're in a template, but EXPR isn't value dependent, simplify
6341 it. We're supposed to treat:
6343 template <typename T> void f(T[1 + 1]);
6344 template <typename T> void f(T[2]);
6346 as two declarations of the same function, for example. */
6349 {
6350 processing_template_decl_sentinel s;
6352 }
6354 }
6356 tree
6358 {
6360 }
6362 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
6363 an uninstantiated expression. */
6365 tree
6367 {
6371 {
6374 else
6375 {
6376 processing_template_decl_sentinel s;
6378 }
6379 }
6381 }
6383 /* True iff T is a specialization of a variable template. */
6385 bool
6387 {
6392 }
6394 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
6395 template declaration, or a TYPE_DECL for an alias declaration. */
6397 bool
6399 {
6407 }
6409 /* If T is a specialization of an alias template, return it; otherwise return
6410 NULL_TREE. If TRANSPARENT_TYPEDEFS is true, look through other aliases. */
6412 tree
6415 {
6419 /* It's an alias template specialization if it's an alias and its
6420 TYPE_NAME is a specialization of a primary template. */
6422 {
6429 transparent_typedefs);
6430 }
6433 }
6435 /* An alias template is complex from a SFINAE perspective if a template-id
6436 using that alias can be ill-formed when the expansion is not, as with
6437 the void_t template. We determine this by checking whether the
6438 expansion for the alias template uses all its template parameters. */
6440 struct uses_all_template_parms_data
6441 {
6444 };
6446 static int
6448 {
6456 }
6458 /* for_each_template_parm any_fn callback for complex_alias_template_p. */
6460 static int
6462 {
6463 /* An alias template with a pack expansion that expands a pack from the
6464 enclosing class needs to be considered complex, to avoid confusion with
6465 the same pack being used as an argument to the alias's own template
6466 parameter (91966). */
6473 {
6481 }
6483 }
6485 static bool
6487 {
6488 /* A renaming alias isn't complex. */
6492 /* Any other constrained alias is complex. */
6512 }
6514 /* If T is a specialization of a complex alias template with dependent
6515 template-arguments, return it; otherwise return NULL_TREE. If T is a
6516 typedef to such a specialization, return the specialization. */
6518 tree
6520 {
6531 && (any_dependent_template_arguments_p
6536 {
6539 }
6542 }
6544 /* Return the number of innermost template parameters in TMPL. */
6546 static int
6548 {
6551 }
6553 /* Return either TMPL or another template that it is equivalent to under DR
6554 1286: An alias that just changes the name of a template is equivalent to
6555 the other template. */
6557 static tree
6559 {
6562 {
6563 /* Determine if the alias is equivalent to an underlying template. */
6565 /* The underlying type may have been ill-formed. Don't proceed. */
6578 /* Does the alias add cv-quals? */
6586 /* If TMPL adds or changes any constraints, it isn't equivalent. I think
6587 it's appropriate to treat a less-constrained alias as equivalent. */
6591 /* Alias is equivalent. Strip it and repeat. */
6593 }
6596 }
6598 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6599 must be a reference-to-function or a pointer-to-function type, as specified
6600 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6601 and check that the resulting function has external linkage. */
6603 static tree
6605 tsubst_flags_t complain)
6606 {
6609 linkage_kind linkage;
6627 /* [temp.arg.nontype]/1
6629 A template-argument for a non-type, non-template template-parameter
6630 shall be one of:
6631 [...]
6632 -- the address of an object or function with external [C++11: or
6633 internal] linkage. */
6637 {
6639 {
6646 else
6649 }
6651 }
6655 {
6657 {
6663 else
6667 }
6669 }
6671 accept:
6673 {
6676 else
6678 }
6683 }
6685 /* Subroutine of convert_nontype_argument.
6686 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6687 Emit an error otherwise. */
6689 static bool
6691 tsubst_flags_t complain)
6692 {
6708 {
6714 else
6716 }
6718 }
6720 /* Returns TRUE iff the address of OP is value-dependent.
6722 14.6.2.4 [temp.dep.temp]:
6723 A non-integral non-type template-argument is dependent if its type is
6724 dependent or it has either of the following forms
6725 qualified-id
6726 & qualified-id
6727 and contains a nested-name-specifier which specifies a class-name that
6728 names a dependent type.
6730 We generalize this to just say that the address of a member of a
6731 dependent class is value-dependent; the above doesn't cover the
6732 address of a static data member named with an unqualified-id. */
6734 static bool
6736 {
6739 /* We could use get_inner_reference here, but there's no need;
6740 this is only relevant for template non-type arguments, which
6741 can only be expressed as &id-expression. */
6743 {
6747 }
6750 }
6752 /* The next set of functions are used for providing helpful explanatory
6753 diagnostics for failed overload resolution. Their messages should be
6754 indented by two spaces for consistency with the messages in
6755 call.c */
6757 static int
6759 {
6761 }
6763 /* Other failure functions should call this one, to provide a single function
6764 for setting a breakpoint on. */
6766 static int
6768 {
6770 }
6772 static int
6774 {
6779 }
6781 static int
6783 {
6789 }
6791 static int
6793 {
6797 }
6799 static int
6801 {
6804 " template parameter %qD is not a parameter pack, but "
6808 }
6810 static int
6812 {
6815 " template argument %qE does not match "
6819 }
6821 static int
6823 {
6827 }
6829 static int
6831 {
6837 }
6839 static int
6841 {
6843 {
6848 else
6850 " deduced conflicting values for non-type parameter "
6852 }
6854 }
6856 static int
6858 {
6861 " variable-sized array type %qT is not "
6863 arg);
6865 }
6867 static int
6869 {
6873 arg);
6875 }
6877 static int
6879 {
6881 {
6887 else
6892 }
6894 }
6896 static int
6898 {
6900 }
6902 static int
6905 {
6907 }
6909 static int
6912 {
6918 }
6920 static int
6923 {
6926 {
6934 }
6936 }
6938 static int
6940 {
6943 " template parameters of a template template argument are "
6946 }
6948 static int
6950 {
6956 }
6958 static int
6960 {
6965 }
6967 /* True if T is a C++20 template parameter object to store the argument for a
6968 template parameter of class type. */
6970 bool
6972 {
6975 }
6977 /* Subroutine of convert_nontype_argument, to check whether EXPR, as an
6978 argument for TYPE, points to an unsuitable object.
6980 Also adjust the type of the index in C++20 array subobject references. */
6982 static bool
6984 {
6986 {
6987 CASE_CONVERT:
6989 complain);
6993 complain);
6996 {
7001 }
7005 {
7011 {
7015 /* Canonicalize array offsets to ptrdiff_t; how they were
7016 written doesn't matter for subobject identity. */
7019 }
7022 {
7025 "%qE is not a valid template argument of type %qT "
7028 }
7030 {
7033 "%qE is not a valid template argument of type %qT "
7037 }
7040 {
7043 "%qE is not a valid template argument of type %qT "
7046 }
7047 /* C++17: For a non-type template-parameter of reference or pointer
7048 type, the value of the constant expression shall not refer to (or
7049 for a pointer type, shall not be the address of):
7050 * a subobject (4.5),
7051 * a temporary object (15.2),
7052 * a string literal (5.13.5),
7053 * the result of a typeid expression (8.2.8), or
7054 * a predefined __func__ variable (11.4.1). */
7056 {
7059 decl);
7061 }
7063 && !(same_type_ignoring_top_level_qualifiers_p
7066 {
7071 }
7073 {
7077 decl);
7079 }
7080 }
7088 else
7089 {
7091 {
7094 "because %qD is a variable, not the address of "
7097 }
7098 else
7099 {
7105 }
7106 }
7107 }
7110 }
7112 /* The template arguments corresponding to template parameter objects of types
7113 that contain pointers to members. */
7117 /* Return a VAR_DECL for the C++20 template parameter object corresponding to
7118 template argument EXPR. */
7120 static tree
7122 {
7127 {
7132 }
7136 /* This is no longer a compound literal. */
7155 {
7156 /* If EXPR contains any PTRMEM_CST, they will get clobbered by
7157 lower_var_init before we're done mangling. So store the original
7158 value elsewhere. */
7161 }
7166 }
7168 /* Return the actual template argument corresponding to template parameter
7169 object VAR. */
7171 tree
7173 {
7177 }
7179 /* Attempt to convert the non-type template parameter EXPR to the
7180 indicated TYPE. If the conversion is successful, return the
7181 converted value. If the conversion is unsuccessful, return
7182 NULL_TREE if we issued an error message, or error_mark_node if we
7183 did not. We issue error messages for out-and-out bad template
7184 parameters, but not simply because the conversion failed, since we
7185 might be just trying to do argument deduction. Both TYPE and EXPR
7186 must be non-dependent.
7188 The conversion follows the special rules described in
7189 [temp.arg.nontype], and it is much more strict than an implicit
7190 conversion.
7192 This function is called twice for each template argument (see
7193 lookup_template_class for a more accurate description of this
7194 problem). This means that we need to handle expressions which
7195 are not valid in a C++ source, but can be created from the
7196 first call (for instance, casts to perform conversions). These
7197 hacks can go away after we fix the double coercion problem. */
7199 static tree
7201 {
7202 tree expr_type;
7205 /* Detect immediately string literals as invalid non-type argument.
7206 This special-case is not needed for correctness (we would easily
7207 catch this later), but only to provide better diagnostic for this
7208 common user mistake. As suggested by DR 100, we do not mention
7209 linkage issues in the diagnostic as this is not the point. */
7211 {
7217 }
7219 /* Add the ADDR_EXPR now for the benefit of
7220 value_dependent_expression_p. */
7223 {
7227 }
7229 /* If we are in a template, EXPR may be non-dependent, but still
7230 have a syntactic, rather than semantic, form. For example, EXPR
7231 might be a SCOPE_REF, rather than the VAR_DECL to which the
7232 SCOPE_REF refers. Preserving the qualifying scope is necessary
7233 so that access checking can be performed when the template is
7234 instantiated -- but here we need the resolved form so that we can
7235 convert the argument. */
7247 /* If the argument is non-dependent, perform any conversions in
7248 non-dependent context as well. */
7257 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
7258 to a non-type argument of "nullptr". */
7262 /* In C++11, integral or enumeration non-type template arguments can be
7263 arbitrary constant expressions. Pointer and pointer to
7264 member arguments can be general constant expressions that evaluate
7265 to a null value, but otherwise still need to be of a specific form. */
7267 {
7269 /* A PTRMEM_CST is already constant, and a valid template
7270 argument for a parameter of pointer to member type, we just want
7271 to leave it in that form rather than lower it to a
7275 {
7276 /* C++17: A template-argument for a non-type template-parameter shall
7277 be a converted constant expression (8.20) of the type of the
7278 template-parameter. */
7281 /* Make sure we return NULL_TREE only if we have really issued
7282 an error, as described above. */
7285 {
7288 }
7292 }
7294 {
7300 }
7301 }
7305 else
7308 /* HACK: Due to double coercion, we can get a
7309 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
7310 which is the tree that we built on the first call (see
7311 below when coercing to reference to object or to reference to
7312 function). We just strip everything and get to the arg.
7313 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
7314 for examples. */
7316 {
7322 {
7323 /* ??? Maybe we could use convert_from_reference here, but we
7324 would need to relax its constraints because the NOP_EXPR
7325 could actually change the type to something more cv-qualified,
7326 and this is not folded by convert_from_reference. */
7331 && (same_type_ignoring_top_level_qualifiers_p
7334 {
7337 }
7338 }
7339 }
7341 /* [temp.arg.nontype]/5, bullet 1
7343 For a non-type template-parameter of integral or enumeration type,
7344 integral promotions (_conv.prom_) and integral conversions
7345 (_conv.integral_) are applied. */
7348 {
7350 {
7355 }
7360 /* Notice that there are constant expressions like '4 % 0' which
7361 do not fold into integer constants. */
7363 {
7365 {
7369 else
7375 /* else cxx_constant_value complained but gave us
7376 a real constant, so go ahead. */
7378 {
7379 /* Some assemble time constant expressions like
7380 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
7381 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
7382 as we can emit them into .rodata initializers of
7383 variables, yet they can't fold into an INTEGER_CST at
7384 compile time. Refuse them here. */
7389 }
7390 }
7391 else
7393 }
7395 /* Avoid typedef problems. */
7398 }
7399 /* [temp.arg.nontype]/5, bullet 2
7401 For a non-type template-parameter of type pointer to object,
7402 qualification conversions (_conv.qual_) and the array-to-pointer
7403 conversion (_conv.array_) are applied. */
7405 {
7408 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
7409 decay_conversion or an explicit cast. If it's a problematic cast,
7410 we'll complain about it below. */
7412 {
7417 {
7420 }
7421 }
7423 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
7425 A template-argument for a non-type, non-template template-parameter
7426 shall be one of: [...]
7428 -- the name of a non-type template-parameter;
7429 -- the address of an object or function with external linkage, [...]
7430 expressed as "& id-expression" where the & is optional if the name
7431 refers to a function or array, or if the corresponding
7432 template-parameter is a reference.
7434 Here, we do not care about functions, as they are invalid anyway
7435 for a parameter of type pointer-to-object. */
7438 /* Non-type template parameters are OK. */
7439 ;
7444 /* Other values, like integer constants, might be valid
7445 non-type arguments of some other type. */
7455 }
7456 /* [temp.arg.nontype]/5, bullet 3
7458 For a non-type template-parameter of type reference to object, no
7459 conversions apply. The type referred to by the reference may be more
7460 cv-qualified than the (otherwise identical) type of the
7461 template-argument. The template-parameter is bound directly to the
7462 template-argument, which must be an lvalue. */
7464 {
7466 expr_type))
7470 {
7475 }
7478 {
7483 }
7485 /* [temp.arg.nontype]/1
7487 A template-argument for a non-type, non-template template-parameter
7488 shall be one of: [...]
7490 -- the address of an object or function with external linkage. */
7493 {
7496 {
7499 "because a reference variable does not have a constant "
7502 }
7503 }
7506 /* OK, dependent reference. We don't want to ask whether a DECL is
7508 else
7509 {
7514 }
7518 }
7519 /* [temp.arg.nontype]/5, bullet 4
7521 For a non-type template-parameter of type pointer to function, only
7522 the function-to-pointer conversion (_conv.func_) is applied. If the
7523 template-argument represents a set of overloaded functions (or a
7524 pointer to such), the matching function is selected from the set
7525 (_over.over_). */
7527 {
7528 /* If the argument is a template-id, we might not have enough
7529 context information to decay the pointer. */
7531 {
7535 }
7538 /* Null pointer values are OK in C++11. */
7544 }
7545 /* [temp.arg.nontype]/5, bullet 5
7547 For a non-type template-parameter of type reference to function, no
7548 conversions apply. If the template-argument represents a set of
7549 overloaded functions, the matching function is selected from the set
7550 (_over.over_). */
7552 {
7554 {
7556 {
7561 }
7563 }
7568 }
7569 /* [temp.arg.nontype]/5, bullet 6
7571 For a non-type template-parameter of type pointer to member function,
7572 no conversions apply. If the template-argument represents a set of
7573 overloaded member functions, the matching member function is selected
7574 from the set (_over.over_). */
7576 {
7581 /* [temp.arg.nontype] bullet 1 says the pointer to member
7582 expression must be a pointer-to-member constant. */
7587 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
7588 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
7591 }
7592 /* [temp.arg.nontype]/5, bullet 7
7594 For a non-type template-parameter of type pointer to data member,
7595 qualification conversions (_conv.qual_) are applied. */
7597 {
7598 /* [temp.arg.nontype] bullet 1 says the pointer to member
7599 expression must be a pointer-to-member constant. */
7607 }
7609 {
7611 {
7616 }
7618 }
7620 {
7621 /* Replace the argument with a reference to the corresponding template
7622 parameter object. */
7627 }
7628 /* A template non-type parameter must be one of the above. */
7629 else
7632 /* Sanity check: did we actually convert the argument to the
7633 right type? */
7637 }
7639 /* Subroutine of coerce_template_template_parms, which returns 1 if
7640 PARM_PARM and ARG_PARM match using the rule for the template
7641 parameters of template template parameters. Both PARM and ARG are
7642 template parameters; the rest of the arguments are the same as for
7643 coerce_template_template_parms.
7644 */
7645 static int
7647 tree arg,
7648 tsubst_flags_t complain,
7649 tree in_decl,
7650 tree outer_args)
7651 {
7660 {
7662 /* We encounter instantiations of templates like
7663 template <template <template <class> class> class TT>
7664 class C; */
7665 {
7672 }
7673 /* Fall through. */
7678 /* Argument is a parameter pack but parameter is not. */
7683 /* The tsubst call is used to handle cases such as
7685 template <int> class C {};
7686 template <class T, template <T> class TT> class D {};
7687 D<int, C> d;
7689 i.e. the parameter list of TT depends on earlier parameters. */
7691 {
7696 }
7700 /* Argument is a parameter pack but parameter is not. */
7707 }
7710 }
7712 /* Coerce template argument list ARGLIST for use with template
7713 template-parameter TEMPL. */
7715 static tree
7717 tsubst_flags_t complain)
7718 {
7719 /* Consider an example where a template template parameter declared as
7721 template <class T, class U = std::allocator<T> > class TT
7723 The template parameter level of T and U are one level larger than
7724 of TT. To proper process the default argument of U, say when an
7725 instantiation `TT<int>' is seen, we need to build the full
7726 arguments containing {int} as the innermost level. Outer levels,
7727 available when not appearing as default template argument, can be
7728 obtained from the arguments of the enclosing template.
7730 Suppose that TT is later substituted with std::vector. The above
7731 instantiation is `TT<int, std::allocator<T> >' with TT at
7732 level 1, and T at level 2, while the template arguments at level 1
7733 becomes {std::vector} and the inner level 2 is {int}. */
7739 {
7740 /* This is an argument of the current template, so we haven't set
7741 DECL_CONTEXT yet. */
7742 tree relevant_template_parms;
7744 /* Parameter levels that are greater than the level of the given
7745 template template parm are irrelevant. */
7752 }
7759 complain,
7762 }
7764 /* A cache of template template parameters with match-all default
7765 arguments. */
7768 /* T is a bound template template-parameter. Copy its arguments into default
7769 arguments of the template template-parameter's template parameters. */
7771 static tree
7773 {
7796 {
7799 {
7802 }
7803 }
7807 }
7809 /* ARG is a bound potential template template-argument, and PARGS is a list
7810 of arguments for the corresponding template template-parameter. Adjust
7811 PARGS as appropriate for application to ARG's template, and if ARG is a
7812 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7813 arguments to the template template parameter. */
7815 static tree
7817 {
7821 {
7822 /* When comparing two template template-parameters in partial ordering,
7823 rewrite the one currently being used as an argument to have default
7824 arguments for all parameters. */
7830 }
7831 else
7832 {
7833 tree aparms
7838 }
7841 }
7843 /* Subroutine of unify for the case when PARM is a
7844 BOUND_TEMPLATE_TEMPLATE_PARM. */
7846 static int
7849 {
7853 /* The template template parm might be variadic and the argument
7854 not, so flatten both argument lists. */
7859 {
7860 /* In keeping with P0522R0, adjust P's template arguments
7861 to apply to A's template; then flatten it again. */
7869 /* If the P0522 adjustment eliminated a pack expansion, deduce
7870 empty packs. */
7876 }
7877 else
7878 {
7879 /* Deduce arguments T, i from TT<T> or TT<i>.
7880 We check each element of PARMVEC and ARGVEC individually
7881 rather than the whole TREE_VEC since they can have
7882 different number of elements, which is allowed under N2555. */
7886 /* Check if the parameters end in a pack, making them
7887 variadic. */
7894 /* If the template argument list of P contains a pack
7895 expansion that is not the last template argument, the
7896 entire template argument list is a non-deduced
7897 context. */
7915 DEDUCE_EXACT,
7918 }
7921 }
7923 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7924 template template parameters. Both PARM_PARMS and ARG_PARMS are
7925 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7926 or PARM_DECL.
7928 Consider the example:
7929 template <class T> class A;
7930 template<template <class U> class TT> class B;
7932 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7933 the parameters to A, and OUTER_ARGS contains A. */
7935 static int
7937 tree arg_parms,
7938 tsubst_flags_t complain,
7939 tree in_decl,
7940 tree outer_args)
7941 {
7953 {
7954 /* P0522R0: A template template-parameter P is at least as specialized as
7955 a template template-argument A if, given the following rewrite to two
7956 function templates, the function template corresponding to P is at
7957 least as specialized as the function template corresponding to A
7958 according to the partial ordering rules for function templates
7959 ([temp.func.order]). Given an invented class template X with the
7960 template parameter list of A (including default arguments):
7962 * Each of the two function templates has the same template parameters,
7963 respectively, as P or A.
7965 * Each function template has a single function parameter whose type is
7966 a specialization of X with template arguments corresponding to the
7967 template parameters from the respective function template where, for
7968 each template parameter PP in the template parameter list of the
7969 function template, a corresponding template argument AA is formed. If
7970 PP declares a parameter pack, then AA is the pack expansion
7971 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7973 If the rewrite produces an invalid type, then P is not at least as
7974 specialized as A. */
7976 /* So coerce P's args to apply to A's parms, and then deduce between A's
7977 args and the converted args. If that succeeds, A is at least as
7978 specialized as P, so they match.*/
7986 {
7992 }
7993 }
7995 /* Determine whether we have a parameter pack at the end of the
7996 template template parameter's template parameter list. */
7998 {
8005 {
8019 }
8020 }
8026 /* Check all of the template parameters except the parameter pack at
8027 the end (if any). */
8029 {
8038 outer_args))
8041 }
8044 {
8045 /* Check each of the template parameters in the template
8046 argument against the template parameter pack at the end of
8047 the template template parameter. */
8054 {
8061 outer_args))
8063 }
8064 }
8067 }
8069 /* Verifies that the deduced template arguments (in TARGS) for the
8070 template template parameters (in TPARMS) represent valid bindings,
8071 by comparing the template parameter list of each template argument
8072 to the template parameter list of its corresponding template
8073 template parameter, in accordance with DR150. This
8074 routine can only be called after all template arguments have been
8075 deduced. It will return TRUE if all of the template template
8076 parameter bindings are okay, FALSE otherwise. */
8077 bool
8079 {
8083 /* We're dealing with template parms in this process. */
8089 {
8094 {
8099 {
8100 /* Look inside the argument pack. */
8103 }
8106 {
8110 /* Extract the next argument from the argument
8111 pack. */
8115 /* Look at the pattern of the pack expansion. */
8118 /* Extract the template parameters from the template
8119 argument. */
8125 /* Verify that we can coerce the template template
8126 parameters from the template argument to the template
8127 parameter. This requires an exact match. */
8129 && !coerce_template_template_parms
8131 targ_parms,
8132 tf_none,
8133 tparm,
8134 targs))
8135 {
8138 }
8139 }
8140 }
8141 }
8143 out:
8147 }
8149 /* Since type attributes aren't mangled, we need to strip them from
8150 template type arguments. */
8152 tree
8154 {
8164 }
8166 /* And from inside dependent non-type arguments like sizeof(Type). */
8168 static tree
8170 {
8180 }
8182 /* A template declaration can be substituted for a constrained
8183 template template parameter only when the argument is no more
8184 constrained than the parameter. */
8186 static bool
8188 {
8191 /* For now, allow constrained template template arguments
8192 and unconstrained template template parameters. */
8196 /* If the template parameter is constrained, we need to rewrite its
8197 constraints in terms of the ARG's template parameters. This ensures
8198 that all of the template parameter types will have the same depth.
8200 Note that this is only valid when coerce_template_template_parm is
8201 true for the innermost template parameters of PARM and ARG. In other
8202 words, because coercion is successful, this conversion will be valid. */
8205 {
8212 }
8215 }
8217 // Convert a placeholder argument into a binding to the original
8218 // parameter. The original parameter is saved as the TREE_TYPE of
8219 // ARG.
8222 {
8225 }
8227 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
8228 because one of them is dependent. But we need to represent the
8229 conversion for the benefit of cp_tree_equal. */
8231 static tree
8233 {
8234 /* Auto parms get no conversion. */
8237 /* We don't need or want to add this conversion now if we're going to use the
8238 argument for deduction. */
8250 }
8252 /* Convert the indicated template ARG as necessary to match the
8253 indicated template PARM. Returns the converted ARG, or
8254 error_mark_node if the conversion was unsuccessful. Error and
8255 warning messages are issued under control of COMPLAIN. This
8256 conversion is for the Ith parameter in the parameter list. ARGS is
8257 the full set of template arguments deduced so far. */
8259 static tree
8261 tree arg,
8262 tree args,
8263 tsubst_flags_t complain,
8265 tree in_decl)
8266 {
8267 tree orig_arg;
8268 tree val;
8274 /* Trivially convert placeholders. */
8283 {
8284 /* The template argument was the name of some
8285 member function. That's usually
8286 invalid, but static members are OK. In any
8287 case, grab the underlying fields/functions
8288 and issue an error later if required. */
8290 }
8298 /* When determining whether an argument pack expansion is a template,
8299 look at the pattern. */
8303 /* Deal with an injected-class-name used as a template template arg. */
8305 {
8308 {
8318 }
8319 }
8321 is_tmpl_type =
8337 {
8339 {
8343 }
8346 "to refer to a type member of a template parameter, "
8351 typename_type,
8352 complain);
8355 }
8357 {
8359 {
8361 {
8366 {
8367 /* The template argument is a type, but we're expecting
8368 an expression. */
8373 /* [temp.arg]/2: "In a template-argument, an ambiguity
8374 between a type-id and an expression is resolved to a
8375 type-id, regardless of the form of the corresponding
8376 template-parameter." So give the user a clue. */
8379 "for non-type template parameter is treated as "
8381 }
8385 else
8388 }
8389 }
8391 }
8393 {
8395 {
8402 else
8405 }
8407 }
8410 /* We already did the appropriate conversion when packing args. */
8413 {
8415 {
8417 /* The number of argument required is not known yet.
8418 Just accept it for now. */
8420 else
8421 {
8423 tree argparm;
8425 /* Strip alias templates that are equivalent to another
8426 template. */
8432 args))
8433 {
8436 /* TEMPLATE_TEMPLATE_PARM node is preferred over
8437 TEMPLATE_DECL. */
8439 {
8444 }
8445 }
8446 else
8447 {
8449 {
8456 }
8459 }
8461 // Check that the constraints are compatible before allowing the
8462 // substitution.
8465 {
8467 {
8473 }
8475 }
8476 }
8477 }
8478 else
8480 /* We only form one instance of each template specialization.
8481 Therefore, if we use a non-canonical variant (i.e., a
8482 typedef), any future messages referring to the type will use
8483 the typedef, which is confusing if those future uses do not
8484 themselves also use the typedef. */
8487 }
8488 else
8489 {
8494 /* We don't have enough levels of args to do any substitution. This
8497 {
8501 }
8502 else
8508 /* Drop top-level cv-qualifiers on the substituted/deduced type of
8509 this non-type template parameter, as per [temp.param]/6. */
8517 /* We used to call digest_init here. However, digest_init
8518 will report errors, which we don't want when complain
8519 is zero. More importantly, digest_init will try too
8520 hard to convert things: for example, `0' should not be
8521 converted to pointer type at this point according to
8522 the standard. Accepting this is not merely an
8523 extension, since deciding whether or not these
8524 conversions can occur is part of determining which
8525 function template to call, or whether a given explicit
8526 argument specification is valid. */
8528 else
8529 {
8532 }
8543 {
8544 /* Reject template arguments that are references to built-in
8545 functions with no library fallbacks. */
8554 }
8557 {
8558 /* Strip typedefs from the SCOPE_REF. */
8561 complain);
8564 }
8565 }
8568 }
8570 /* Coerces the remaining template arguments in INNER_ARGS (from
8571 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
8572 Returns the coerced argument pack. PARM_IDX is the position of this
8573 parameter in the template parameter list. ARGS is the original
8574 template argument list. */
8575 static tree
8578 tree args,
8579 tree inner_args,
8581 tree new_args,
8583 tree in_decl,
8584 tsubst_flags_t complain)
8585 {
8588 tree packed_args;
8589 tree argument_pack;
8596 {
8597 /* When the template parameter is a non-type template parameter pack
8598 or template template parameter pack whose type or template
8599 parameters use parameter packs, we know exactly how many arguments
8600 we are looking for. Build a vector of the instantiated decls for
8601 these template parameters in PACKED_PARMS. */
8602 /* We can't use make_pack_expansion here because it would interpret a
8603 _DECL as a use rather than a declaration. */
8617 /* If we're doing a partial instantiation of a member template,
8618 verify that all of the types used for the non-type
8619 template parameter pack are, in fact, valid for non-type
8620 template parameters. */
8623 {
8626 {
8631 }
8632 /* We don't know how many args we have yet, just
8633 use the unconverted ones for now. */
8635 }
8638 }
8639 /* Check if we have a placeholder pack, which indicates we're
8640 in the context of a introduction list. In that case we want
8641 to match this pack to the single placeholder. */
8645 {
8648 }
8649 else
8652 /* Convert the remaining arguments, which will be a part of the
8653 parameter pack "parm". */
8656 {
8662 {
8663 /* Once we've packed as many args as we have types, stop. */
8667 /* We don't know how many args we have yet, just
8668 use the unconverted ones for now. */
8670 else
8672 }
8675 {
8678 }
8679 else
8682 in_decl);
8686 }
8690 {
8695 }
8700 else
8701 {
8704 }
8711 }
8713 /* Returns the number of pack expansions in the template argument vector
8714 ARGS. */
8716 static int
8718 {
8723 {
8727 }
8729 }
8731 /* Convert all template arguments to their appropriate types, and
8732 return a vector containing the innermost resulting template
8733 arguments. If any error occurs, return error_mark_node. Error and
8734 warning messages are issued under control of COMPLAIN.
8736 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8737 for arguments not specified in ARGS. Otherwise, if
8738 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
8739 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
8740 USE_DEFAULT_ARGS is false, then all arguments must be specified in
8741 ARGS. */
8743 static tree
8745 tree args,
8746 tree in_decl,
8747 tsubst_flags_t complain,
8750 {
8752 tree orig_inner_args;
8753 tree inner_args;
8754 tree new_args;
8755 tree new_inner_args;
8757 /* When used as a boolean value, indicates whether this is a
8758 variadic template parameter list. Since it's an int, we can also
8759 subtract it from nparms to get the number of non-variadic
8760 parameters. */
8765 /* Adjustment to nparms for fixed parameter packs. */
8770 /* Likewise for parameters with default arguments. */
8778 /* Determine if there are any parameter packs or default arguments. */
8780 {
8788 }
8791 /* If there are no parameters that follow a parameter pack, we need to
8792 expand any argument packs so that we can deduce a parameter pack from
8793 some non-packed args followed by an argument pack, as in variadic85.C.
8794 If there are such parameters, we need to leave argument packs intact
8795 so the arguments are assigned properly. This can happen when dealing
8796 with a nested class inside a partial specialization of a class
8797 template, as in variadic92.C, or when deducing a template parameter pack
8798 from a sub-declarator, as in variadic114.C. */
8802 /* Count any pack expansion args. */
8808 && require_all_args
8809 && !variadic_args_p
8810 && (!use_default_args
8813 {
8814 bad_nargs:
8816 {
8818 {
8822 }
8823 else
8830 }
8833 }
8834 /* We can't pass a pack expansion to a non-pack parameter of an alias
8835 template (DR 1430). */
8839 && variadic_args_p
8841 {
8843 {
8845 {
8851 {
8854 "pack expansion argument for non-pack parameter "
8856 else
8858 "pack expansion argument for non-pack parameter "
8862 }
8863 }
8865 found:;
8866 }
8868 }
8870 /* We need to evaluate the template arguments, even though this
8871 template-id may be nested within a "sizeof". */
8872 cp_evaluated ev;
8878 {
8879 tree arg;
8880 tree parm;
8882 /* Get the Ith template parameter. */
8886 {
8889 }
8891 /* Calculate the next argument. */
8894 else
8900 {
8901 /* Some arguments will be placed in the
8902 template parameter pack PARM. */
8909 {
8910 /* We don't know how many args we have yet, just use the
8911 unconverted (and still packed) ones for now. */
8915 }
8919 /* Store this argument. */
8921 {
8922 lost++;
8923 /* We are done with all of the arguments. */
8926 }
8927 else
8928 {
8932 {
8935 }
8936 }
8939 }
8941 {
8943 {
8944 /* "If every valid specialization of a variadic template
8945 requires an empty template parameter pack, the template is
8946 ill-formed, no diagnostic required." So check that the
8947 pattern works with this parameter. */
8952 in_decl);
8954 {
8959 }
8961 /* Recover from missing typename. */
8965 /* We don't know how many args we have yet, just
8966 use the unconverted ones for now. */
8970 }
8971 }
8973 {
8974 /* There must be a default arg in this case. */
8977 /* The position of the first default template argument,
8978 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8979 Record that. */
8983 }
8984 else
8988 {
8991 }
8993 {
8994 /* This can occur if there was an error in the template
8995 parameter list itself (which we would already have
8996 reported) that we are trying to recover from, e.g., a class
8997 template with a parameter list such as
8998 template<typename..., typename> (cpp0x/variadic150.C). */
9001 /* This can also happen with a fixed parameter pack (71834). */
9004 }
9005 else
9011 lost++;
9014 }
9017 {
9018 /* If we had fixed parameter packs, we didn't know how many arguments we
9019 actually needed earlier; now we do. */
9023 }
9026 {
9027 /* We had some pack expansion arguments that will only work if the packs
9028 are empty, but wait until instantiation time to complain.
9029 See variadic-ttp3.C. */
9031 /* Except that we can't provide empty packs to alias templates or
9032 concepts when there are no corresponding parameters. Basically,
9033 we can get here with this:
9035 template<typename T> concept C = true;
9037 template<typename... Args>
9038 requires C<Args...>
9039 void f();
9041 When parsing C<Args...>, we try to form a concept check of
9042 C<?, Args...>. Without the extra check for substituting an empty
9043 pack past the last parameter, we can accept the check as valid.
9045 FIXME: This may be valid for alias templates (but I doubt it).
9047 FIXME: The error could be better also. */
9049 {
9054 }
9065 }
9068 {
9071 }
9078 }
9080 /* Convert all template arguments to their appropriate types, and
9081 return a vector containing the innermost resulting template
9082 arguments. If any error occurs, return error_mark_node. Error and
9083 warning messages are not issued.
9085 Note that no function argument deduction is performed, and default
9086 arguments are used to fill in unspecified arguments. */
9087 tree
9089 {
9091 }
9093 /* Convert all template arguments to their appropriate type, and
9094 instantiate default arguments as needed. This returns a vector
9095 containing the innermost resulting template arguments, or
9096 error_mark_node if unsuccessful. */
9097 tree
9099 tsubst_flags_t complain)
9100 {
9102 }
9104 /* Like coerce_template_parms. If PARMS represents all template
9105 parameters levels, this function returns a vector of vectors
9106 representing all the resulting argument levels. Note that in this
9107 case, only the innermost arguments are coerced because the
9108 outermost ones are supposed to have been coerced already.
9110 Otherwise, if PARMS represents only (the innermost) vector of
9111 parameters, this function returns a vector containing just the
9112 innermost resulting arguments. */
9114 static tree
9116 tree args,
9117 tree in_decl,
9118 tsubst_flags_t complain,
9121 {
9124 tree coerced_args;
9127 {
9129 tree level;
9135 {
9136 tree l;
9140 require_all_args,
9141 use_default_args);
9142 else
9149 }
9150 }
9151 else
9154 require_all_args,
9155 use_default_args);
9157 }
9159 /* Returns true if T is a wrapper to make a C++20 template parameter
9160 object const. */
9162 static bool
9164 {
9170 }
9172 /* Returns 1 if template args OT and NT are equivalent. */
9174 int
9176 {
9189 /* DR 1558: Don't treat an alias template specialization with dependent
9190 arguments as equivalent to its underlying type when used as a template
9191 argument; we need them to be distinct so that we substitute into the
9192 specialization arguments at instantiation time. And aliases can't be
9193 equivalent without being ==, so we don't need to look any deeper.
9195 During partial ordering, however, we need to treat them normally so we can
9196 order uses of the same alias with different cv-qualification (79960). */
9202 /* For member templates */
9215 {
9219 }
9220 else
9221 {
9222 /* Try to treat a template non-type argument that has been converted
9223 to the parameter type as equivalent to one that hasn't yet. */
9237 }
9238 }
9240 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
9241 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
9242 NEWARG_PTR with the offending arguments if they are non-NULL. */
9244 int
9248 {
9261 {
9266 {
9272 }
9273 }
9275 }
9279 {
9281 }
9283 /* Implement a freelist interface for objects of type T.
9285 Head is a separate object, rather than a regular member, so that we
9286 can define it as a GTY deletable pointer, which is highly
9287 desirable. A data member could be declared that way, but then the
9288 containing object would implicitly get GTY((user)), which would
9289 prevent us from instantiating freelists as global objects.
9290 Although this way we can create freelist global objects, they're
9291 such thin wrappers that instantiating temporaries at every use
9292 loses nothing and saves permanent storage for the freelist object.
9294 Member functions next, anew, poison and reinit have default
9295 implementations that work for most of the types we're interested
9296 in, but if they don't work for some type, they should be explicitly
9297 specialized. See the comments before them for requirements, and
9298 the example specializations for the tree_list_freelist. */
9300 class freelist
9301 {
9302 /* Return the next object in a chain. We could just do type
9303 punning, but if we access the object with its underlying type, we
9304 avoid strict-aliasing trouble. This needs only work between
9305 poison and reinit. */
9308 /* Return a newly allocated, uninitialized or minimally-initialized
9309 object of type T. Any initialization performed by anew should
9310 either remain across the life of the object and the execution of
9311 poison, or be redone by reinit. */
9314 /* Optionally scribble all over the bits holding the object, so that
9315 they become (mostly?) uninitialized memory. This is called while
9316 preparing to make the object part of the free list. */
9321 #ifdef ENABLE_GC_CHECKING
9322 /* Poison the data, to indicate the data is garbage. */
9325 #endif
9326 /* Let valgrind know the object is free. */
9329 /* Let valgrind know the next portion of the object is available,
9330 but uninitialized. */
9332 }
9334 /* Bring an object that underwent at least one lifecycle after anew
9335 and before the most recent free and poison, back to a usable
9336 state, reinitializing whatever is needed for it to be
9337 functionally equivalent to an object just allocated and returned
9338 by anew. This may poison or clear the next field, used by
9339 freelist housekeeping after poison was called. */
9343 #ifdef ENABLE_GC_CHECKING
9345 #endif
9346 /* Let valgrind know the entire object is available, but
9347 uninitialized. */
9349 }
9351 /* Reference a GTY-deletable pointer that points to the first object
9352 in the free list proper. */
9355 /* Construct a freelist object chaining objects off of HEAD. */
9358 /* Add OBJ to the free object list. The former head becomes OBJ's
9359 successor. */
9361 {
9365 }
9367 /* Take an object from the free list, if one is available, or
9368 allocate a new one. Objects taken from the free list should be
9369 regarded as filled with garbage, except for bits that are
9370 configured to be preserved across free and alloc. */
9372 {
9374 {
9379 }
9380 else
9382 }
9383 };
9385 /* Explicitly specialize the interfaces for freelist<tree_node>: we
9386 want to allocate a TREE_LIST using the usual interface, and ensure
9387 TREE_CHAIN remains functional. Alas, we have to duplicate a bit of
9388 build_tree_list logic in reinit, so this could go out of sync. */
9392 {
9394 }
9396 inline tree
9398 {
9400 }
9404 {
9410 #ifdef ENABLE_GC_CHECKING
9413 /* Poison the data, to indicate the data is garbage. */
9416 #endif
9417 /* Let valgrind know the object is free. */
9419 /* But we still want to use the TREE_CODE and TREE_CHAIN parts. */
9423 #ifdef ENABLE_GC_CHECKING
9425 /* Keep TREE_CHAIN functional. */
9427 #else
9429 #endif
9430 }
9434 {
9437 #ifdef ENABLE_GC_CHECKING
9441 #endif
9443 /* Let valgrind know the entire object is available, but
9444 uninitialized. */
9447 #ifdef ENABLE_GC_CHECKING
9449 #else
9451 #endif
9452 }
9454 /* Point to the first object in the TREE_LIST freelist. */
9456 /* Return the/an actual TREE_LIST freelist. */
9459 {
9461 }
9463 /* Point to the first object in the tinst_level freelist. */
9465 /* Return the/an actual tinst_level freelist. */
9468 {
9470 }
9472 /* Point to the first object in the pending_template freelist. */
9474 /* Return the/an actual pending_template freelist. */
9477 {
9479 }
9481 /* Build the TREE_LIST object out of a split list, store it
9482 permanently, and return it. */
9483 tree
9485 {
9494 }
9498 /* Increment OBJ's refcount unless it is already infinite. */
9501 {
9505 }
9507 /* Release storage for OBJ and node, if it's a TREE_LIST. */
9508 void
9510 {
9514 }
9516 /* Decrement OBJ's refcount if not infinite. If it reaches zero, release
9517 OBJ's DECL and OBJ, and start over with the tinst_level object that
9518 used to be referenced by OBJ's NEXT. */
9519 static void
9521 {
9525 {
9529 }
9530 }
9532 /* Modify PTR so that it points to OBJ, adjusting the refcounts of OBJ
9533 and of the former PTR. Omitting the second argument is equivalent
9534 to passing (T*)NULL; this is allowed because passing the
9535 zero-valued integral constant NULL confuses type deduction and/or
9536 overload resolution. */
9538 static void
9540 {
9544 }
9546 static void
9548 {
9558 /* We are called both from instantiate_decl, where we've already had a
9559 tinst_level pushed, and instantiate_template, where we haven't.
9560 Compensate. */
9562 level = !current_tinst_level
9574 else
9583 }
9586 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
9587 ARGLIST. Valid choices for FNS are given in the cp-tree.def
9588 documentation for TEMPLATE_ID_EXPR. */
9590 tree
9592 {
9599 {
9602 }
9605 {
9608 unknown_type_node,
9610 arglist);
9612 }
9615 }
9617 /* Within the scope of a template class S<T>, the name S gets bound
9618 (in build_self_reference) to a TYPE_DECL for the class, not a
9619 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
9620 or one of its enclosing classes, and that type is a template,
9621 return the associated TEMPLATE_DECL. Otherwise, the original
9622 DECL is returned.
9624 Also handle the case when DECL is a TREE_LIST of ambiguous
9625 injected-class-names from different bases. */
9627 tree
9629 {
9633 /* DR 176: A lookup that finds an injected-class-name (10.2
9634 [class.member.lookup]) can result in an ambiguity in certain cases
9635 (for example, if it is found in more than one base class). If all of
9636 the injected-class-names that are found refer to specializations of
9637 the same class template, and if the name is followed by a
9638 template-argument-list, the reference refers to the class template
9639 itself and not a specialization thereof, and is not ambiguous. */
9641 {
9644 {
9650 }
9653 else
9655 }
9661 }
9663 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
9664 parameters, find the desired type.
9666 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
9668 IN_DECL, if non-NULL, is the template declaration we are trying to
9669 instantiate.
9671 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
9672 the class we are looking up.
9674 Issue error and warning messages under control of COMPLAIN.
9676 If the template class is really a local class in a template
9677 function, then the FUNCTION_CONTEXT is the function in which it is
9678 being instantiated.
9680 ??? Note that this function is currently called *twice* for each
9681 template-id: the first time from the parser, while creating the
9682 incomplete type (finish_template_type), and the second type during the
9683 real instantiation (instantiate_template_class). This is surely something
9684 that we want to avoid. It also causes some problems with argument
9685 coercion (see convert_nontype_argument for more information on this). */
9687 static tree
9690 {
9692 tree t;
9695 spec_entry elt;
9696 hashval_t hash;
9699 {
9703 else
9704 {
9711 }
9714 }
9716 {
9719 /* If we are declaring a constructor, say A<T>::A<T>, we will get
9720 an implicit typename for the second A. Deal with it. */
9725 {
9728 }
9729 }
9732 {
9735 }
9737 {
9741 }
9743 {
9746 }
9748 /* Issue an error message if we didn't find a template. */
9750 {
9754 }
9757 /* Make sure it's a user visible template, if it was named by
9758 the user. */
9761 {
9763 {
9767 }
9769 }
9773 /* An alias that just changes the name of a template is equivalent to the
9774 other template, so if any of the arguments are pack expansions, strip
9775 the alias to avoid problems with a pack expansion passed to a non-pack
9776 alias template parameter (DR 1430). */
9781 {
9782 tree parm;
9791 }
9792 else
9793 {
9795 tree gen_tmpl;
9796 tree type_decl;
9804 /* An error occurred while building the template TEMPL, and a
9805 diagnostic has most certainly been emitted for that
9806 already. Let's propagate that error. */
9818 {
9819 /* We've been given an incomplete set of template arguments.
9820 For example, given:
9822 template <class T> struct S1 {
9823 template <class U> struct S2 {};
9824 template <class U> struct S2<U*> {};
9825 };
9827 we will be called with an ARGLIST of `U*', but the
9828 TEMPLATE will be `template <class T> template
9829 <class U> struct S1<T>::S2'. We must fill in the missing
9830 arguments. */
9834 }
9836 /* Now we should have enough arguments. */
9839 /* From here on, we're only interested in the most general
9840 template. */
9842 /* Shortcut looking up the current class scope again. */
9849 /* Calculate the BOUND_ARGS. These will be the args that are
9850 actually tsubst'd into the definition to create the
9851 instantiation. */
9853 complain,
9858 /* We were unable to bind the arguments. */
9861 /* In the scope of a template class, explicit references to the
9862 template class refer to the type of the template, not any
9863 instantiation of it. For example, in:
9865 template <class T> class C { void f(C<T>); }
9867 the `C<T>' is just the same as `C'. Outside of the
9868 class, however, such a reference is an instantiation. */
9872 {
9877 }
9879 /* If we already have this specialization, return it. */
9889 /* If the template's constraints are not satisfied,
9890 then we cannot form a valid type.
9892 Note that the check is deferred until after the hash
9893 lookup. This prevents redundant checks on previously
9894 instantiated specializations. */
9898 {
9900 {
9901 auto_diagnostic_group d;
9904 }
9906 }
9910 /* If the deduced arguments are invalid, then the binding
9911 failed. */
9915 complain))
9922 /* This occurs when the user has tried to define a tagged type
9923 in a scope that forbids it. We emitted an error during the
9924 parse. We didn't complete the bail out then, so here we
9925 are. */
9930 {
9933 }
9934 else
9943 /* Create the type. */
9945 {
9946 /* The user referred to a specialization of an alias
9947 template represented by GEN_TMPL.
9949 [temp.alias]/2 says:
9951 When a template-id refers to the specialization of an
9952 alias template, it is equivalent to the associated
9953 type obtained by substitution of its
9954 template-arguments for the template-parameters in the
9955 type-id of the alias template. */
9958 /* Note that the call above (by indirectly calling
9959 register_specialization in tsubst_decl) registers the
9960 TYPE_DECL representing the specialization of the alias
9961 template. So next time someone substitutes ARGLIST for
9962 the template parms into the alias template (GEN_TMPL),
9963 she'll get that TYPE_DECL back. */
9967 }
9969 {
9971 {
9982 }
9983 else
9984 {
9985 /* We don't want to call start_enum for this type, since
9986 the values for the enumeration constants may involve
9987 template parameters. And, no one should be interested
9988 in the enumeration constants for such a type. */
9991 }
9995 }
9997 {
9998 /* Lambda closures are regenerated in tsubst_lambda_expr, not
9999 instantiated here. */
10007 /* A local class. Make sure the decl gets registered properly. */
10014 /* This instantiation is another name for the primary
10015 template type. Set the TYPE_CANONICAL field
10016 appropriately. */
10019 /* Some of the template arguments require structural
10020 equality testing, so this template class requires
10021 structural equality testing. */
10023 }
10024 else
10027 /* If we called start_enum or pushtag above, this information
10028 will already be set up. */
10031 {
10038 }
10041 /* Although GEN_TMPL is the TEMPLATE_DECL, it has the same value
10042 of export flag. We want to propagate this because it might
10043 be a friend declaration that pushes a new hidden binding. */
10047 {
10053 {
10056 }
10057 }
10061 {
10065 {
10066 tree attributes
10074 }
10075 }
10077 /* Let's consider the explicit specialization of a member
10078 of a class template specialization that is implicitly instantiated,
10079 e.g.:
10080 template<class T>
10081 struct S
10082 {
10083 template<class U> struct M {}; //#0
10084 };
10086 template<>
10087 template<>
10088 struct S<int>::M<char> //#1
10089 {
10090 int i;
10091 };
10092 [temp.expl.spec]/4 says this is valid.
10094 In this case, when we write:
10095 S<int>::M<char> m;
10097 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
10098 the one of #0.
10100 When we encounter #1, we want to store the partial instantiation
10101 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
10103 For all cases other than this "explicit specialization of member of a
10104 class template", we just want to store the most general template into
10105 the CLASSTYPE_TI_TEMPLATE of M.
10107 This case of "explicit specialization of member of a class template"
10108 only happens when:
10109 1/ the enclosing class is an instantiation of, and therefore not
10110 the same as, the context of the most general template, and
10111 2/ we aren't looking at the partial instantiation itself, i.e.
10112 the innermost arguments are not the same as the innermost parms of
10113 the most general template.
10115 So it's only when 1/ and 2/ happens that we want to use the partial
10116 instantiation of the member template in lieu of its most general
10117 template. */
10121 /* the enclosing class must be an instantiation... */
10124 {
10128 tree partial_inst_args =
10135 use_partial_inst_tmpl =
10136 /*...and we must not be looking at the partial instantiation
10137 itself. */
10139 partial_inst_args);
10140 }
10143 /* This case is easy; there are no member templates involved. */
10145 else
10146 {
10147 /* This is a full instantiation of a member template. Find
10148 the partial instantiation of which this is an instance. */
10150 /* Temporarily reduce by one the number of levels in the ARGLIST
10151 so as to avoid comparing the last set of arguments. */
10153 /* We don't use COMPLAIN in the following call because this isn't
10154 the immediate context of deduction. For instance, tf_partial
10155 could be set here as we might be at the beginning of template
10156 argument deduction when any explicitly specified template
10157 arguments are substituted into the function type. tf_partial
10158 could lead into trouble because we wouldn't find the partial
10159 instantiation that might have been created outside tf_partial
10160 context, because the levels of template parameters wouldn't
10161 match, because in a tf_partial context, tsubst doesn't reduce
10162 TEMPLATE_PARM_LEVEL. */
10165 /* FOUND is either a proper class type, or an alias
10166 template specialization. In the later case, it's a
10167 TYPE_DECL, resulting from the substituting of arguments
10168 for parameters in the TYPE_DECL of the alias template
10169 done earlier. So be careful while getting the template
10170 of FOUND. */
10172 ? found
10179 {
10180 /* If this partial instantiation is specialized, we want to
10181 use it for hash table lookup. */
10185 }
10186 }
10188 /* Build template info for the new specialization. */
10198 /* Note this use of the partial instantiation so we can check it
10199 later in maybe_process_partial_specialization. */
10207 /* Now that the type has been registered on the instantiations
10208 list, we set up the enumerators. Because the enumeration
10209 constants may involve the enumeration type itself, we make
10210 sure to register the type first, and then create the
10211 constants. That way, doing tsubst_expr for the enumeration
10212 constants won't result in recursive calls here; we'll find
10213 the instantiation and exit above. */
10217 /* If the type makes use of template parameters, the
10218 code that generates debugging information will crash. */
10221 /* Possibly limit visibility based on template args. */
10228 }
10229 }
10231 /* Wrapper for lookup_template_class_1. */
10233 tree
10236 {
10237 tree ret;
10243 }
10245 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
10247 tree
10249 {
10253 /* The type of the expression is NULL_TREE since the template-id could refer
10254 to an explicit or partial specialization. */
10256 }
10258 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
10260 tree
10262 {
10278 {
10280 {
10281 auto_diagnostic_group d;
10284 }
10286 }
10289 }
10291 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
10292 TARGS template args, and instantiate it if it's not dependent. */
10294 tree
10296 tsubst_flags_t complain)
10297 {
10300 {
10303 }
10306 }
10308 /* If the set of template parameters PARMS contains a template parameter
10309 at the given LEVEL and INDEX, then return this parameter. Otherwise
10310 return NULL_TREE. */
10312 static tree
10314 {
10323 /* As in template_parm_to_arg. */
10326 else
10331 }
10333 /* Return the template parameter from PARMS that positionally corresponds
10334 to the template parameter PARM, or else return NULL_TREE. */
10336 static tree
10338 {
10342 }
10344 \f
10345 struct pair_fn_data
10346 {
10347 tree_fn_t fn;
10348 tree_fn_t any_fn;
10350 /* True when we should also visit template parameters that occur in
10351 non-deduced contexts. */
10354 };
10356 /* Called from for_each_template_parm via walk_tree. */
10358 static tree
10360 {
10367 #define WALK_SUBTREE(NODE) \
10368 do \
10369 { \
10370 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
10371 pfd->include_nondeduced_p, \
10372 pfd->any_fn); \
10373 if (result) goto out; \
10374 } \
10375 while (0)
10385 {
10389 /* Fall through. */
10395 else
10405 /* Since we're not going to walk subtrees, we have to do this
10406 explicitly here. */
10408 /* Fall through. */
10411 /* Check the return type. */
10414 /* Check the parameter types. Since default arguments are not
10415 instantiated until they are needed, the TYPE_ARG_TYPES may
10416 contain expressions that involve template parameters. But,
10417 no-one should be looking at them yet. And, once they're
10418 instantiated, they don't contain template parameters, so
10419 there's no point in looking at them then, either. */
10420 {
10421 tree parm;
10426 /* Since we've already handled the TYPE_ARG_TYPES, we don't
10427 want walk_tree walking into them itself. */
10429 }
10432 {
10436 }
10455 /* Fall through. */
10467 /* Record template parameters such as `T' inside `TT<T>'. */
10469 /* Fall through. */
10481 /* A template template parameter is encountered. */
10485 /* Already substituted template template parameter */
10490 /* A template-id in a TYPENAME_TYPE might be a deduced context after
10491 partial instantiation. */
10504 /* If there's no type, then this thing must be some expression
10505 involving template parameters. */
10514 /* These are non-deduced contexts. */
10535 {
10539 /* Recursively walk the type of each constraint variable. */
10542 {
10545 }
10546 }
10551 }
10553 #undef WALK_SUBTREE
10555 /* We didn't find any template parameters we liked. */
10556 out:
10558 }
10560 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
10561 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
10562 call FN with the parameter and the DATA.
10563 If FN returns nonzero, the iteration is terminated, and
10564 for_each_template_parm returns 1. Otherwise, the iteration
10565 continues. If FN never returns a nonzero value, the value
10566 returned by for_each_template_parm is 0. If FN is NULL, it is
10567 considered to be the function which always returns 1.
10569 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
10570 parameters that occur in non-deduced contexts. When false, only
10571 visits those template parameters that can be deduced. */
10573 static tree
10577 tree_fn_t any_fn)
10578 {
10580 tree result;
10582 /* Set up. */
10588 /* Walk the tree. (Conceptually, we would like to walk without
10589 duplicates, but for_each_template_parm_r recursively calls
10590 for_each_template_parm, so we would need to reorganize a fair
10591 bit to use walk_tree_without_duplicates, so we keep our own
10592 visited list.) */
10595 else
10598 for_each_template_parm_r,
10602 /* Clean up. */
10604 {
10607 }
10610 }
10612 struct find_template_parameter_info
10613 {
10618 {}
10622 tree parm_list;
10623 tree ctx_parms;
10625 };
10627 /* Appends the declaration of T to the list in DATA. */
10629 static int
10631 {
10634 /* Template parameters declared within the expression are not part of
10635 the parameter mapping. For example, in this concept:
10637 template<typename T>
10638 concept C = requires { <expr> } -> same_as<int>;
10640 the return specifier same_as<int> declares a new decltype parameter
10641 that must not be part of the parameter mapping. The same is true
10642 for generic lambda parameters, lambda template parameters, etc. */
10650 /* We want the underlying TEMPLATE_TEMPLATE_PARM, not the
10651 BOUND_TEMPLATE_TEMPLATE_PARM itself. */
10654 /* This template parameter might be an argument to a cached dependent
10655 specalization that was formed earlier inside some other template, in
10656 which case the parameter is not among the ones that are in-scope.
10657 Look in CTX_PARMS to find the corresponding in-scope template
10658 parameter, and use it instead. */
10662 /* Arguments like const T yield parameters like const T. This means that
10663 a template-id like X<T, const T> would yield two distinct parameters:
10664 T and const T. Adjust types to their unqualified versions. */
10670 /* Verify the parameter we found has a valid index. */
10672 {
10678 }
10681 }
10683 /* Ensure that we recursively examine certain terms that are not normally
10684 visited in for_each_template_parm_r. */
10686 static int
10688 {
10691 #define WALK_SUBTREE(NODE) \
10692 do \
10693 { \
10694 for_each_template_parm (NODE, keep_template_parm, data, \
10695 &ftpi->visited, true, \
10696 any_template_parm_r); \
10697 } \
10698 while (0)
10700 /* A mention of a member alias/typedef is a use of all of its template
10701 arguments, including those from the enclosing class, so we don't use
10702 alias_template_specialization_p here. */
10708 {
10710 /* Type constraints of a placeholder type may contain parameters. */
10717 /* Search through references to variable templates. */
10724 /* A parameter or constraint variable may also depend on a template
10725 parameter without explicitly naming it. */
10730 {
10731 /* If T is a member template that shares template parameters with
10732 ctx_parms, we need to mark all those parameters for mapping. */
10745 {
10750 }
10751 }
10755 {
10756 /* Look in the parms and body. */
10760 }
10765 /* The conversion-type-id of a conversion operator may be dependent. */
10771 }
10773 /* Keep walking. */
10775 }
10777 /* Returns a list of unique template parameters found within T, where CTX_PARMS
10778 are the template parameters in scope. */
10780 tree
10782 {
10790 }
10792 /* Returns true if T depends on any template parameter. */
10794 int
10796 {
10817 else
10823 }
10825 /* Returns true iff we're processing an incompletely instantiated function
10826 template. Useful instead of processing_template_decl because the latter
10827 is set to 0 during instantiate_non_dependent_expr. */
10829 bool
10831 {
10832 /* Inspect the less volatile cfun->decl instead of current_function_decl;
10833 the latter might get set for e.g. access checking during satisfaction. */
10842 }
10844 /* Returns true if T depends on any template parameter with level LEVEL. */
10846 bool
10848 {
10851 }
10853 /* Returns true if the signature of DECL depends on any template parameter from
10854 its enclosing class. */
10856 bool
10858 {
10867 {
10870 {
10875 template_parm_outer_level,
10885 }
10886 }
10894 }
10896 /* Returns TRUE iff INST is an instantiation we don't need to do in an
10897 ill-formed translation unit, i.e. a variable or function that isn't
10898 usable in a constant expression. */
10902 {
10907 }
10909 /* Returns TRUE iff we should refuse to instantiate DECL because it's
10910 neglectable and instantiated from within an erroneous instantiation. */
10912 static bool
10914 {
10925 }
10933 /* We're starting to instantiate D; record the template instantiation context
10934 at LOC for diagnostics and to restore it later. */
10936 bool
10938 {
10942 {
10943 /* Tell error.c not to try to instantiate any templates. */
10946 "template instantiation depth exceeds maximum of %d"
10948 max_tinst_depth);
10950 }
10952 /* If the current instantiation caused problems, don't let it instantiate
10953 anything else. Do allow deduction substitution and decls usable in
10954 constant expressions. */
10956 {
10957 /* Avoid no_linkage_errors and unused function warnings for this
10958 decl. */
10961 }
10963 /* When not -quiet, dump template instantiations other than functions, since
10964 announce_function will take care of those. */
10986 }
10988 /* We're starting substitution of TMPL<ARGS>; record the template
10989 substitution context for diagnostics and to restore it later. */
10991 bool
10993 {
10995 }
10997 /* We're starting to instantiate D; record INPUT_LOCATION and the
10998 template instantiation context for diagnostics and to restore it
10999 later. */
11001 bool
11003 {
11005 }
11007 /* Likewise, but record LOC as the program location. */
11009 bool
11011 {
11014 }
11016 /* We're done instantiating this template; return to the instantiation
11017 context. */
11019 void
11021 {
11022 /* Restore the filename and line number stashed away when we started
11023 this instantiation. */
11027 }
11029 /* We're instantiating a deferred template; restore the template
11030 instantiation context in which the instantiation was requested, which
11031 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
11033 static tree
11035 {
11047 }
11049 /* Returns the TINST_LEVEL which gives the original instantiation
11050 context. */
11054 {
11060 }
11062 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
11063 vector of template arguments, as for tsubst.
11065 Returns an appropriate tsubst'd friend declaration. */
11067 static tree
11069 {
11070 tree new_friend;
11075 /* This was a friend declared with an explicit template
11076 argument list, e.g.:
11078 friend void f<>(T);
11080 to indicate that f was a template instantiation, not a new
11081 function declaration. Now, we have to figure out what
11082 instantiation of what template. */
11083 {
11085 tree new_args;
11086 tree tmpl;
11089 /* Friend functions are looked up in the containing namespace scope.
11090 We must enter that scope, to avoid finding member functions of the
11091 current class with same name. */
11106 tsk_none);
11108 }
11114 /* The NEW_FRIEND will look like an instantiation, to the
11115 compiler, but is not an instantiation from the point of view of
11116 the language. For example, we might have had:
11118 template <class T> struct S {
11119 template <class U> friend void f(T, U);
11120 };
11122 Then, in S<int>, template <class U> void f(int, U) is not an
11123 instantiation of anything. */
11127 {
11133 /* Substitute TEMPLATE_PARMS_CONSTRAINTS so that parameter levels will
11134 match in decls_match. */
11139 }
11141 /* The mangled name for the NEW_FRIEND is incorrect. The function
11142 is not a template instantiation and should not be mangled like
11143 one. Therefore, we forget the mangling here; we'll recompute it
11144 later if we need it. */
11146 {
11149 }
11152 {
11153 tree old_decl;
11154 tree ns;
11156 /* We must save some information from NEW_FRIEND before calling
11157 duplicate decls since that function will free NEW_FRIEND if
11158 possible. */
11168 {
11169 /* This declaration is a `primary' template. */
11174 }
11176 /* Inside pushdecl_namespace_level, we will push into the
11177 current namespace. However, the friend function should go
11178 into the namespace of the template. */
11188 {
11189 /* This new friend declaration matched an existing
11190 declaration. For example, given:
11192 template <class T> void f(T);
11193 template <class U> class C {
11194 template <class T> friend void f(T) {}
11195 };
11197 the friend declaration actually provides the definition
11198 of `f', once C has been instantiated for some type. So,
11199 old_decl will be the out-of-class template declaration,
11200 while new_friend is the in-class definition.
11202 But, if `f' was called before this point, the
11203 instantiation of `f' will have DECL_TI_ARGS corresponding
11204 to `T' but not to `U', references to which might appear
11205 in the definition of `f'. Previously, the most general
11206 template for an instantiation of `f' was the out-of-class
11207 version; now it is the in-class version. Therefore, we
11208 run through all specialization of `f', adding to their
11209 DECL_TI_ARGS appropriately. In particular, they need a
11210 new set of outer arguments, corresponding to the
11211 arguments for this class instantiation.
11213 The same situation can arise with something like this:
11215 friend void f(int);
11216 template <class T> class C {
11217 friend void f(T) {}
11218 };
11220 when `C<int>' is instantiated. Now, `f(int)' is defined
11221 in the class. */
11224 /* On the other hand, if the in-class declaration does
11225 *not* provide a definition, then we don't want to alter
11226 existing definitions. We can just leave everything
11227 alone. */
11228 ;
11229 else
11230 {
11234 /* Overwrite whatever template info was there before, if
11235 any, with the new template information pertaining to
11236 the declaration. */
11240 {
11241 /* We should have called reregister_specialization in
11242 duplicate_decls. */
11247 /* Instantiate it if the global has already been used. */
11251 }
11252 else
11253 {
11254 tree t;
11256 /* Indicate that the old function template is a partial
11257 instantiation. */
11265 /* Reassign any specializations already in the hash table
11266 to the new more general template, and add the
11267 additional template args. */
11271 {
11273 spec_entry elt;
11285 register_specialization
11288 }
11290 }
11291 }
11293 /* The information from NEW_FRIEND has been merged into OLD_DECL
11294 by duplicate_decls. */
11296 }
11297 }
11298 else
11299 {
11303 /* In the code
11304 template <class T> class C {
11305 template <class U> friend void C1<U>::f (); // case 1
11306 friend void C2<T>::f (); // case 2
11307 };
11308 we only need to make sure CONTEXT is a complete type for
11309 case 2. To distinguish between the two cases, we note that
11310 CONTEXT of case 1 remains dependent type after tsubst while
11311 this isn't true for case 2. */
11321 {
11323 /* do_friend adds the TEMPLATE_DECL for any member friend
11324 template even if it isn't a member template, i.e.
11325 template <class T> friend A<T>::f();
11326 Look through it in that case. */
11330 /* Check to see that the declaration is really present, and,
11331 possibly obtain an improved declaration. */
11336 }
11337 }
11340 }
11342 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
11343 template arguments, as for tsubst.
11345 Returns an appropriate tsubst'd friend type or error_mark_node on
11346 failure. */
11348 static tree
11350 {
11351 tree tmpl;
11354 {
11357 }
11362 else
11363 {
11366 }
11372 {
11373 /* The friend template has already been declared. Just
11374 check to see that the declarations match, and install any new
11375 default parameters. We must tsubst the default parameters,
11376 of course. We only need the innermost template parameters
11377 because that is all that redeclare_class_template will look
11378 at. */
11381 {
11389 }
11390 }
11391 else
11392 {
11393 /* The friend template has not already been declared. In this
11394 case, the instantiation of the template class will cause the
11395 injection of this template into the namespace scope. */
11399 {
11400 /* The new TMPL is not an instantiation of anything, so we
11401 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
11402 for the new type because that is supposed to be the
11403 corresponding template decl, i.e., TMPL. */
11410 /* Substitute into and set the constraints on the new declaration. */
11412 {
11418 }
11420 /* Inject this template into the enclosing namspace scope. */
11422 }
11423 }
11427 else
11431 }
11433 /* Returns zero if TYPE cannot be completed later due to circularity.
11434 Otherwise returns one. */
11436 static int
11438 {
11448 else
11450 }
11455 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
11456 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
11458 static tree
11461 {
11470 {
11477 clauses
11481 else
11483 }
11487 {
11489 tree varid
11500 {
11504 {
11506 {
11514 }
11515 else
11516 {
11520 {
11521 bool allow_string
11533 {
11534 location_t loc
11536 match_loc);
11542 "integer expression or string "
11544 else
11548 }
11551 {
11552 location_t loc
11554 match_loc);
11558 }
11560 }
11561 }
11562 }
11563 }
11565 }
11566 /* If the first attribute argument is an identifier, don't
11567 pass it through tsubst. Attributes like mode, format,
11568 cleanup and several target specific attributes expect it
11569 unmodified. */
11571 {
11572 tree chain
11577 }
11579 {
11580 /* An attribute pack expansion. */
11589 {
11593 }
11595 }
11596 else
11605 }
11607 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
11608 unchanged or a new TREE_LIST chain. */
11610 static tree
11613 {
11618 {
11622 }
11626 {
11629 {
11632 {
11638 }
11639 }
11641 }
11644 }
11646 /* Apply any attributes which had to be deferred until instantiation
11647 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
11648 ARGS, COMPLAIN, IN_DECL are as tsubst. Returns true normally,
11649 false on error. */
11651 static bool
11654 {
11655 tree t;
11662 {
11666 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
11667 to our attributes parameter. */
11669 }
11670 else
11671 {
11673 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
11674 lookup_template_class_1, and should be preserved. */
11678 }
11680 /* save_template_attributes puts the dependent attributes at the beginning of
11681 the list; find the non-dependent ones. */
11687 /* Apply any non-dependent attributes. */
11690 /* And then any dependent ones. */
11694 {
11699 {
11702 }
11705 }
11710 }
11712 /* The template TMPL is being instantiated with the template arguments TARGS.
11713 Perform the access checks that we deferred when parsing the template. */
11715 static void
11717 {
11727 {
11735 /* Make access check error messages point to the location
11736 of the use of the typedef. */
11740 }
11741 }
11743 static tree
11745 {
11747 tree typedecl;
11748 tree pbinfo;
11749 tree base_list;
11751 tree fn_context;
11760 /* Figure out which template is being instantiated. */
11764 /* Mark the type as in the process of being defined. */
11767 /* We may be in the middle of deferred access check. Disable
11768 it now. */
11771 /* Determine what specialization of the original template to
11772 instantiate. */
11777 {
11778 /* This TYPE is actually an instantiation of a partial
11779 specialization. We replace the innermost set of ARGS with
11780 the arguments appropriate for substitution. For example,
11781 given:
11783 template <class T> struct S {};
11784 template <class T> struct S<T*> {};
11786 and supposing that we are instantiating S<int*>, ARGS will
11787 presently be {int*} -- but we need {int}. */
11790 }
11791 else
11792 {
11795 }
11797 /* If the template we're instantiating is incomplete, then clearly
11798 there's nothing we can do. */
11800 {
11801 /* We can try again later. */
11804 }
11806 /* If we've recursively instantiated too many templates, stop. */
11814 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
11819 else
11820 {
11823 }
11824 /* Use #pragma pack from the template context. */
11830 /* Set the input location to the most specialized template definition.
11831 This is needed if tsubsting causes an error. */
11845 {
11848 /* Adjust visibility for template arguments. */
11850 }
11856 /* We should never instantiate a nested class before its enclosing
11857 class; we need to look up the nested class by name before we can
11858 instantiate it, and that lookup should instantiate the enclosing
11859 class. */
11864 /* Defer access checking while we substitute into the types named in
11865 the base-clause. */
11868 {
11869 tree pbase_binfo;
11872 /* Substitute into each of the bases to determine the actual
11873 basetypes. */
11875 {
11876 tree base;
11882 {
11883 expanded_bases =
11890 }
11893 {
11895 /* Extract the already-expanded base class. */
11897 else
11898 /* Substitute to figure out the base class. */
11900 NULL_TREE);
11908 }
11909 }
11911 /* The list is now in reverse order; correct that. */
11913 }
11914 /* Now call xref_basetypes to set up all the base-class
11915 information. */
11923 /* Now that our base classes are set up, enter the scope of the
11924 class, so that name lookups into base classes, etc. will work
11925 correctly. This is precisely analogous to what we do in
11926 begin_class_definition when defining an ordinary non-template
11927 class, except we also need to push the enclosing classes. */
11930 /* Now check accessibility of the types named in its base-clause,
11931 relative to the scope of the class. */
11934 /* A vector to hold members marked with attribute used. */
11937 /* Now members are processed in the order of declaration. */
11940 {
11944 {
11946 {
11948 /* A closure type for a lambda in an NSDMI or default argument.
11949 Ignore it; it will be regenerated when needed. */
11956 /* If the member is a class template, then -- even after
11957 substitution -- there may be dependent types in the
11958 template argument list for the class. We increment
11959 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
11960 that function will assume that no types are dependent
11961 when outside of a template. */
11971 {
11975 /* Unfortunately, lookup_template_class sets
11976 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
11977 instantiation (i.e., for the type of a member
11978 template class nested within a template class.)
11979 This behavior is required for
11980 maybe_process_partial_specialization to work
11981 correctly, but is not accurate in this case;
11982 the TAG is not an instantiation of anything.
11983 (The corresponding TEMPLATE_DECL is an
11984 instantiation, but the TYPE is not.) */
11987 /* Now, install the tag. We don't use pushtag
11988 because that does too much work -- creating an
11989 implicit typedef, which we've already done. */
11994 }
11995 }
11997 {
11998 tree r;
12007 /* Instantiate members marked with attribute used. */
12013 }
12016 /* A closure type for a lambda in an NSDMI or default argument.
12018 else
12019 {
12020 /* Build new TYPE_FIELDS. */
12025 {
12026 tree r;
12031 /* The file and line for this declaration, to
12032 assist in error message reporting. Since we
12033 called push_tinst_level above, we don't need to
12034 restore these. */
12044 {
12045 /* A capture pack became multiple fields. */
12048 }
12051 {
12055 {
12056 /* In [temp.inst]:
12058 [t]he initialization (and any associated
12059 side-effects) of a static data member does
12060 not occur unless the static data member is
12061 itself used in a way that requires the
12062 definition of the static data member to
12063 exist.
12065 Therefore, we do not substitute into the
12066 initialized for the static data member here. */
12067 finish_static_data_member_decl
12073 /* Instantiate members marked with attribute used. */
12076 }
12078 {
12079 /* Determine whether R has a valid type and can be
12080 completed later. If R is invalid, then its type
12081 is replaced by error_mark_node. */
12087 {
12088 /* If R's type couldn't be completed and
12089 it isn't a flexible array member (whose
12090 type is incomplete by definition) give
12091 an error. */
12094 }
12099 {
12102 }
12106 }
12108 /* If it is a TYPE_DECL for a class-scoped
12109 ENUMERAL_TYPE, such a thing will already have
12110 been added to the field list by tsubst_enum
12111 in finish_member_declaration case above. */
12115 {
12118 }
12119 }
12120 }
12121 }
12122 }
12123 else
12124 {
12127 {
12128 /* Build new CLASSTYPE_FRIEND_CLASSES. */
12134 {
12135 /* template <class T> friend class C; */
12138 }
12140 {
12141 /* template <class T> friend class C::D; */
12147 }
12150 {
12151 /* This could be either
12153 friend class T::C;
12155 when dependent_type_p is false or
12157 template <class U> friend class T::C;
12159 otherwise. */
12160 /* Bump processing_template_decl in case this is something like
12161 template <class T> friend struct A<T>::B. */
12168 }
12170 /* friend class C<T>; */
12174 /* Otherwise it's
12176 friend class C;
12178 where C is already declared or
12180 friend class C<int>;
12182 We don't have to do anything in these cases. */
12185 /* Trick make_friend_class into realizing that the friend
12186 we're adding is a template, not an ordinary class. It's
12187 important that we use make_friend_class since it will
12188 perform some error-checking and output cross-reference
12189 information. */
12197 }
12198 else
12199 {
12200 /* Build new DECL_FRIENDLIST. */
12201 tree r;
12203 /* The file and line for this declaration, to
12204 assist in error message reporting. Since we
12205 called push_tinst_level above, we don't need to
12206 restore these. */
12210 {
12213 }
12218 {
12221 }
12222 }
12223 }
12224 }
12227 {
12228 /* Restore these before substituting into the lambda capture
12229 initializers. */
12232 }
12234 /* Set the file and line number information to whatever is given for
12235 the class itself. This puts error messages involving generated
12236 implicit functions at a predictable point, and the same point
12237 that would be used for non-template classes. */
12244 /* We don't instantiate default arguments for member functions. 14.7.1:
12246 The implicit instantiation of a class template specialization causes
12247 the implicit instantiation of the declarations, but not of the
12248 definitions or default arguments, of the class member functions,
12249 member classes, static data members and member templates.... */
12259 /* The vtable for a template class can be emitted in any translation
12260 unit in which the class is instantiated. When there is no key
12261 method, however, finish_struct_1 will already have added TYPE to
12262 the keyed_classes. */
12266 /* Now that we've gone through all the members, instantiate those
12267 marked with attribute used. */
12272 }
12274 /* Wrapper for instantiate_class_template_1. */
12276 tree
12278 {
12279 tree ret;
12284 }
12286 tree
12288 {
12289 tree r;
12295 else
12296 {
12303 }
12306 }
12308 /* Given a function parameter pack TMPL_PARM and some function parameters
12309 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
12310 and set *SPEC_P to point at the next point in the list. */
12312 tree
12314 {
12315 /* Collect all of the extra "packed" parameters into an
12316 argument pack. */
12317 tree argpack;
12328 {
12329 /* The instantiation is still a parameter pack; don't wrap it in a
12330 NONTYPE_ARGUMENT_PACK. */
12333 }
12334 else
12335 {
12336 /* Fill in PARMVEC with all of the parameters. */
12340 {
12346 }
12348 /* Build the argument packs. */
12350 }
12354 }
12356 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
12357 NONTYPE_ARGUMENT_PACK. */
12359 static tree
12361 {
12363 }
12365 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
12366 pack expansion with no extra args, 2 if it has extra args, or 0
12367 if it is not a pack expansion. */
12369 static int
12371 {
12373 /* We're being called before this happens in tsubst_pack_expansion. */
12380 /* A decl pack is itself an expansion. */
12387 }
12390 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
12392 static tree
12394 {
12401 }
12403 /* This is a subroutine of tsubst_pack_expansion.
12405 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
12406 mechanism to store the (non complete list of) arguments of the
12407 substitution and return a non substituted pack expansion, in order
12408 to wait for when we have enough arguments to really perform the
12409 substitution. */
12411 static bool
12415 {
12416 /* If one pack has an expansion and another pack has a normal
12417 argument or if one pack has an empty argument and an another
12418 one hasn't then tsubst_pack_expansion cannot perform the
12419 substitution and need to fall back on the
12420 PACK_EXPANSION_EXTRA mechanism. */
12424 {
12425 /* If all the actual packs are pack expansions, we can still
12426 subsitute directly. */
12428 {
12438 }
12440 }
12443 {
12447 parm_pack;
12449 {
12454 /* We can't substitute a pack expansion with extra args into
12455 our pattern. */
12459 else
12461 }
12464 {
12467 }
12468 }
12470 }
12472 /* [temp.variadic]/6 says that:
12474 The instantiation of a pack expansion [...]
12475 produces a list E1,E2, ..., En, where N is the number of elements
12476 in the pack expansion parameters.
12478 This subroutine of tsubst_pack_expansion produces one of these Ei.
12480 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
12481 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
12482 PATTERN, and each TREE_VALUE is its corresponding argument pack.
12483 INDEX is the index 'i' of the element Ei to produce. ARGS,
12484 COMPLAIN, and IN_DECL are the same parameters as for the
12485 tsubst_pack_expansion function.
12487 The function returns the resulting Ei upon successful completion,
12488 or error_mark_node.
12490 Note that this function possibly modifies the ARGS parameter, so
12491 it's the responsibility of the caller to restore it. */
12493 static tree
12495 tree parm_packs,
12497 tree args /* This parm gets
12499 tsubst_flags_t complain,
12500 tree in_decl)
12501 {
12502 tree t;
12505 /* For each parameter pack, change the substitution of the parameter
12506 pack to the ith argument in its argument pack, then expand the
12507 pattern. */
12509 {
12514 ith_elem_is_expansion |=
12517 /* Select the Ith argument from the pack. */
12521 {
12523 {
12528 }
12529 else
12531 }
12532 else
12533 {
12538 {
12540 /* Update the corresponding argument. */
12542 }
12543 else
12544 /* Re-use the ARGUMENT_PACK_SELECT. */
12546 }
12548 }
12550 /* Substitute into the PATTERN with the (possibly altered)
12551 arguments. */
12553 /* Expanding a fixed parameter pack from
12554 coerce_template_parameter_pack. */
12561 else
12564 /* If the Ith argument pack element is a pack expansion, then
12565 the Ith element resulting from the substituting is going to
12566 be a pack expansion as well. */
12571 }
12573 /* When the unexpanded parameter pack in a fold expression expands to an empty
12574 sequence, the value of the expression is as follows; the program is
12575 ill-formed if the operator is not listed in this table.
12577 && true
12578 || false
12579 , void() */
12581 tree
12583 {
12587 {
12596 }
12602 }
12604 /* Given a fold-expression T and a current LEFT and RIGHT operand,
12605 form an expression that combines the two terms using the
12606 operator of T. */
12608 static tree
12610 {
12614 // Handle compound assignment operators.
12620 {
12628 complain);
12629 }
12630 }
12632 /* Substitute ARGS into the pack of a fold expression T. */
12636 {
12638 }
12640 /* Substitute ARGS into the pack of a fold expression T. */
12644 {
12646 }
12648 /* Expand a PACK of arguments into a grouped as left fold.
12649 Given a pack containing elements A0, A1, ..., An and an
12650 operator @, this builds the expression:
12652 ((A0 @ A1) @ A2) ... @ An
12654 Note that PACK must not be empty.
12656 The operator is defined by the original fold expression T. */
12658 static tree
12660 {
12663 {
12666 }
12668 }
12670 /* Substitute into a unary left fold expression. */
12672 static tree
12674 tree in_decl)
12675 {
12680 {
12684 }
12687 else
12689 }
12691 /* Substitute into a binary left fold expression.
12693 Do ths by building a single (non-empty) vector of argumnts and
12694 building the expression from those elements. */
12696 static tree
12698 tree in_decl)
12699 {
12708 {
12713 }
12721 }
12723 /* Expand a PACK of arguments into a grouped as right fold.
12724 Given a pack containing elementns A0, A1, ..., and an
12725 operator @, this builds the expression:
12727 A0@ ... (An-2 @ (An-1 @ An))
12729 Note that PACK must not be empty.
12731 The operator is defined by the original fold expression T. */
12733 tree
12735 {
12736 // Build the expression.
12740 {
12743 }
12745 }
12747 /* Substitute into a unary right fold expression. */
12749 static tree
12751 tree in_decl)
12752 {
12757 {
12761 }
12764 else
12766 }
12768 /* Substitute into a binary right fold expression.
12770 Do ths by building a single (non-empty) vector of arguments and
12771 building the expression from those elements. */
12773 static tree
12775 tree in_decl)
12776 {
12785 {
12790 }
12799 }
12801 /* Walk through the pattern of a pack expansion, adding everything in
12802 local_specializations to a list. */
12804 class el_data
12805 {
12807 /* Set of variables declared within the pattern. */
12809 /* Set of AST nodes that have been visited by the traversal. */
12811 /* List of local_specializations used within the pattern. */
12812 tree extra;
12813 tsubst_flags_t complain;
12817 };
12818 static tree
12820 {
12826 /* Remember local typedefs (85214). */
12830 {
12836 {
12839 decl2
12845 {
12848 }
12849 }
12850 }
12852 {
12853 /* Since we defer implicit capture, look in the parms and body. */
12859 }
12861 {
12863 /* Don't mess with variables declared within the pattern. */
12866 {
12867 /* Maybe pull out the PARM_DECL for a partial instantiation. */
12870 {
12876 }
12878 {
12879 /* Handle lambda capture here, since we aren't doing any
12880 substitution now, and so tsubst_copy won't call
12881 process_outer_var_ref. */
12885 {
12891 {
12892 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
12893 proxies. */
12895 {
12900 }
12902 }
12903 }
12904 }
12905 }
12909 }
12911 }
12912 static tree
12914 {
12918 }
12920 /* Extract any uses of local_specializations from PATTERN and add them to ARGS
12921 for use in PACK_EXPANSION_EXTRA_ARGS. */
12923 tree
12925 {
12931 }
12933 /* Apply any local specializations from PACK_EXPANSION_EXTRA_ARGS and add the
12934 normal template args to ARGS. */
12936 tree
12938 {
12940 {
12942 {
12943 /* The partial instantiation involved local declarations collected in
12944 extract_local_specs; map from the general template to our local
12945 context. */
12951 /* else inst is already a full instantiation of the pack. */
12953 }
12956 }
12957 #if 1
12958 /* I think we should always be able to substitute dependent args into the
12959 pattern. If that turns out to be incorrect in some cases, enable the
12960 alternate code (and add complain/in_decl parms to this function). */
12962 #else
12964 {
12968 }
12969 else
12970 #endif
12973 }
12975 /* Substitute ARGS into T, which is an pack expansion
12976 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
12977 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
12978 (if only a partial substitution could be performed) or
12979 ERROR_MARK_NODE if there was an error. */
12980 tree
12982 tree in_decl)
12983 {
12984 tree pattern;
12988 tree result;
12995 /* Add in any args remembered from an earlier partial instantiation. */
13000 /* Determine the argument packs that will instantiate the parameter
13001 packs used in the expansion expression. While we're at it,
13002 compute the number of arguments to be expanded and make sure it
13003 is consistent. */
13006 {
13013 {
13019 complain);
13020 else
13024 }
13026 {
13028 {
13031 parm_pack);
13033 }
13036 }
13038 {
13039 /* We know we have correct local_specializations if this
13040 expansion is at function scope, or if we're dealing with a
13041 local parameter in a requires expression; for the latter,
13042 tsubst_requires_expr set it up appropriately. */
13045 else
13046 /* We can't rely on local_specializations for a parameter
13047 name used later in a function declaration (such as in a
13048 late-specified return type). Even if it exists, it might
13049 have the wrong value for a recursive call. */
13053 {
13054 /* This parameter pack was used in an unevaluated context. Just
13055 make a dummy decl, since it's only used for its type. */
13060 /* Partial instantiation of the parm_pack, we can't build
13061 up an argument pack yet. */
13063 else
13065 }
13067 /* This argument pack isn't fully instantiated yet. */
13069 }
13071 {
13075 }
13076 else
13077 {
13086 }
13093 /* This can only happen if we forget to expand an argument
13094 pack somewhere else. Just return an error, silently. */
13095 {
13099 }
13102 {
13106 /* Don't bother trying to do a partial substitution with
13107 incomplete packs; we'll try again after deduction. */
13114 {
13119 pattern);
13120 else
13122 pattern);
13124 }
13126 /* Keep track of the parameter packs and their corresponding
13127 argument packs. */
13130 }
13131 else
13132 {
13133 /* We can't substitute for this parameter pack. We use a flag as
13134 well as the missing_level counter because function parameter
13135 packs don't have a level. */
13138 }
13139 }
13141 /* If the expansion is just T..., return the matching argument pack, unless
13142 we need to call convert_from_reference on all the elements. This is an
13143 important optimization; see c++/68422. */
13146 {
13149 /* If the argument pack is a single pack expansion, pull it out. */
13154 /* Types need no adjustment, nor does sizeof..., and if we still have
13155 some pack expansion args we won't do anything yet. */
13160 /* Also optimize expression pack expansions if we can tell that the
13161 elements won't have reference type. */
13167 /* Otherwise use the normal path so we get convert_from_reference. */
13168 }
13170 /* We cannot expand this expansion expression, because we don't have
13171 all of the argument packs we need. */
13173 {
13174 /* We got some full packs, but we can't substitute them in until we
13175 have values for all the packs. So remember these until then. */
13181 }
13183 /* If NEED_LOCAL_SPECIALIZATIONS then we're in a late-specified return
13184 type, so create our own local specializations map; the current map is
13185 either NULL or (in the case of recursive unification) might have
13186 bindings that we don't want to use or alter. */
13191 {
13192 /* There were no real arguments, we're just replacing a parameter
13193 pack with another version of itself. Substitute into the
13194 pattern and return a PACK_EXPANSION_*. The caller will need to
13195 deal with that. */
13199 else
13205 {
13206 /* This is a fake auto... pack expansion created in add_capture with
13207 _PACKS that don't appear in the pattern. Copy one over. */
13214 }
13216 }
13220 /* For each argument in each argument pack, substitute into the
13221 pattern. */
13225 {
13227 i,
13229 in_decl);
13232 {
13235 }
13236 }
13238 /* Update ARGS to restore the substitution from parameter packs to
13239 their argument packs. */
13241 {
13248 else
13249 {
13257 /* Update the corresponding argument. */
13261 else
13263 }
13264 }
13266 /* If the dependent pack arguments were such that we end up with only a
13267 single pack expansion again, there's no need to keep it in a TREE_VEC. */
13273 }
13275 /* Make an argument pack out of the TREE_VEC VEC. */
13277 static tree
13279 {
13280 tree pack;
13284 else
13285 {
13288 }
13291 }
13293 /* Return an exact copy of template args T that can be modified
13294 independently. */
13296 static tree
13298 {
13306 {
13311 }
13317 }
13319 /* Substitute ARGS into the *_ARGUMENT_PACK orig_arg. */
13321 tree
13323 tree in_decl)
13324 {
13325 /* Substitute into each of the arguments. */
13330 {
13332 {
13335 }
13336 else
13337 {
13340 }
13343 }
13346 }
13348 /* Substitute ARGS into the vector or list of template arguments T. */
13350 tree
13352 {
13364 {
13366 tree new_arg;
13371 {
13372 /* Substitute into an expansion expression. */
13376 /* Add to the expanded length adjustment the number of
13377 expanded arguments. We subtract one from this
13378 measurement, because the argument pack expression
13379 itself is already counted as 1 in
13380 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
13381 the argument pack is empty. */
13383 }
13386 else
13395 }
13400 /* Make space for the expanded arguments coming from template
13401 argument packs. */
13403 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
13404 arguments for a member template.
13405 In that case each TREE_VEC in ORIG_T represents a level of template
13406 arguments, and ORIG_T won't carry any non defaulted argument count.
13407 It will rather be the nested TREE_VECs that will carry one.
13408 In other words, ORIG_T carries a non defaulted argument count only
13409 if it doesn't contain any nested TREE_VEC. */
13411 {
13415 }
13417 {
13421 {
13424 /* Now expand the template argument pack "in place". */
13427 }
13428 else
13429 {
13431 out++;
13432 }
13433 }
13436 }
13438 /* Substitute ARGS into one level PARMS of template parameters. */
13440 static tree
13442 {
13449 {
13457 }
13460 }
13462 /* Return the result of substituting ARGS into the template parameters
13463 given by PARMS. If there are m levels of ARGS and m + n levels of
13464 PARMS, then the result will contain n levels of PARMS. For
13465 example, if PARMS is `template <class T> template <class U>
13466 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
13467 result will be `template <int*, double, class V>'. */
13469 static tree
13471 {
13475 /* When substituting into a template, we must set
13476 PROCESSING_TEMPLATE_DECL as the template parameters may be
13477 dependent if they are based on one-another, and the dependency
13478 predicates are short-circuit outside of templates. */
13485 {
13494 }
13499 }
13501 /* Return the result of substituting ARGS into one template parameter
13502 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
13503 parameter and which TREE_PURPOSE is the default argument of the
13504 template parameter. */
13506 static tree
13508 {
13533 }
13535 /* Substitute the ARGS into the indicated aggregate (or enumeration)
13536 type T. If T is not an aggregate or enumeration type, it is
13537 handled as if by tsubst. IN_DECL is as for tsubst. If
13538 ENTERING_SCOPE is nonzero, T is the context for a template which
13539 we are presently tsubst'ing. Return the substituted value. */
13541 static tree
13543 tree args,
13544 tsubst_flags_t complain,
13545 tree in_decl,
13547 {
13552 {
13557 /* Fall through. */
13561 {
13562 tree argvec;
13563 tree context;
13564 tree r;
13566 /* In "sizeof(X<I>)" we need to evaluate "I". */
13567 cp_evaluated ev;
13569 /* First, determine the context for the type we are looking
13570 up. */
13573 {
13576 /* If context is a nested class inside a class template,
13577 it may still need to be instantiated (c++/33959). */
13579 }
13581 /* Then, figure out what arguments are appropriate for the
13582 type we are trying to find. For example, given:
13584 template <class T> struct S;
13585 template <class T, class U> void f(T, U) { S<U> su; }
13587 and supposing that we are instantiating f<int, double>,
13588 then our ARGS will be {int, double}, but, when looking up
13589 S we only want {double}. */
13596 {
13597 /* See maybe_dependent_member_ref. */
13604 typename_type);
13605 }
13606 else
13607 {
13611 }
13614 }
13615 else
13616 /* This is not a template type, so there's nothing to do. */
13621 }
13622 }
13626 /* Substitute into the default argument ARG (a default argument for
13627 FN), which has the indicated TYPE. */
13629 tree
13631 tsubst_flags_t complain)
13632 {
13635 /* This can happen in invalid code. */
13639 /* Shortcut {}. */
13658 /* This default argument came from a template. Instantiate the
13659 default argument here, not in tsubst. In the case of
13660 something like:
13662 template <class T>
13663 struct S {
13664 static T t();
13665 void f(T = t());
13666 };
13668 we must be careful to do name lookup in the scope of S<T>,
13669 rather than in the current class. */
13675 /* The default argument expression may cause implicitly defined
13676 member functions to be synthesized, which will result in garbage
13677 collection. We must treat this situation as if we were within
13678 the body of function so as to avoid collecting live data on the
13679 stack. */
13688 /* Make sure the default argument is reasonable. */
13701 {
13705 }
13708 }
13710 /* Substitute into all the default arguments for FN. */
13712 static void
13714 {
13715 tree arg;
13716 tree tmpl_args;
13720 /* If this function is not yet instantiated, we certainly don't need
13721 its default arguments. */
13724 /* Don't do this again for clones. */
13730 arg;
13736 complain);
13737 }
13739 /* Hash table mapping a FUNCTION_DECL to its dependent explicit-specifier. */
13742 /* Store a pair to EXPLICIT_SPECIFIER_MAP. */
13744 void
13746 {
13751 }
13753 /* Lookup an element in EXPLICIT_SPECIFIER_MAP. */
13755 static tree
13757 {
13759 }
13761 /* Given T, a FUNCTION_TYPE or METHOD_TYPE, construct and return a corresponding
13762 FUNCTION_TYPE or METHOD_TYPE whose return type is RETURN_TYPE, argument types
13763 are ARG_TYPES, and exception specification is RAISES, and otherwise is
13764 identical to T. */
13766 static tree
13769 {
13772 tree new_type;
13774 {
13777 }
13778 else
13779 {
13781 /* Don't pick up extra function qualifiers from the basetype. */
13784 {
13785 /* [temp.deduct]
13787 Type deduction may fail for any of the following
13788 reasons:
13790 -- Attempting to create "pointer to member of T" when T
13791 is not a class type. */
13794 r);
13796 }
13800 }
13806 }
13808 /* Check if the function type of DECL, a FUNCTION_DECL, agrees with the type of
13809 each of its formal parameters. If there is a disagreement then rebuild
13810 DECL's function type according to its formal parameter types, as part of a
13811 resolution for Core issues 1001/1322. */
13813 static void
13815 {
13818 {
13821 {
13825 {
13828 }
13832 }
13833 }
13844 {
13849 }
13851 {
13861 }
13869 }
13871 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
13873 static tree
13875 tree lambda_fntype)
13876 {
13881 /* Nobody should be tsubst'ing into non-template functions. */
13886 {
13889 }
13891 {
13892 /* If T is not dependent, just return it. */
13897 /* Calculate the most general template of which R is a
13898 specialization. */
13901 /* We're substituting a lambda function under tsubst_lambda_expr but not
13902 directly from it; find the matching function we're already inside.
13903 But don't do this if T is a generic lambda with a single level of
13904 template parms, as in that case we're doing a normal instantiation. */
13910 /* Calculate the complete set of arguments used to
13911 specialize R. */
13913 (DECL_TEMPLATE_RESULT
13919 /* Check to see if we already have this specialization. */
13921 {
13925 }
13926 }
13927 else
13928 {
13929 /* This special case arises when we have something like this:
13931 template <class T> struct S {
13932 friend void f<int>(int, double);
13933 };
13935 Here, the DECL_TI_TEMPLATE for the friend declaration
13936 will be an IDENTIFIER_NODE. We are being called from
13937 tsubst_friend_function, and we want only to create a
13938 new decl (R) with appropriate types so that we can call
13939 determine_specialization. */
13942 }
13959 /* If we hit excessive deduction depth, the type is bogus even if
13960 it isn't error_mark_node, so don't build a decl. */
13964 /* We do NOT check for matching decls pushed separately at this
13965 point, as they may not represent instantiations of this
13966 template, and in any case are considered separate under the
13967 discrete model. */
13971 /* Clear out the mangled name and RTL for the instantiation. */
13974 /* Leave DECL_INITIAL set on deleted instantiations. */
13980 /* Handle explicit(dependent-expr). */
13982 {
13989 }
13991 /* OpenMP UDRs have the only argument a reference to the declared
13992 type. We want to diagnose if the declared type is a reference,
13993 which is invalid, but as references to references are usually
13994 quietly merged, diagnose it here. */
13996 {
13997 tree argtype
14002 "reference type %qT in "
14006 argtype);
14007 }
14010 /* Type-conversion operator. Reconstruct the name, in
14011 case it's the name of one of the template's parameters. */
14021 {
14026 }
14035 /* If this is an instantiation of a function with internal
14036 linkage, we already know what object file linkage will be
14037 assigned to the instantiation. */
14046 /* We'll re-clone as appropriate in instantiate_template. */
14049 /* If we aren't complaining now, return on error before we register
14050 the specialization so that we'll complain eventually. */
14056 /* Associate the constraints directly with the instantiation. We
14057 don't substitute through the constraints; that's only done when
14058 they are checked. */
14071 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
14072 this in the special friend case mentioned above where
14073 GEN_TMPL is NULL. */
14075 {
14080 tree new_r
14083 /* We instantiated this while substituting into
14084 the type earlier (template/friend54.C). */
14087 /* We're not supposed to instantiate default arguments
14088 until they are called, for a template. But, for a
14089 declaration like:
14091 template <class T> void f ()
14092 { extern void g(int i = T()); }
14094 we should do the substitution when the template is
14095 instantiated. We handle the member function case in
14096 instantiate_class_template since the default arguments
14097 might refer to other members of the class. */
14102 }
14104 {
14107 }
14108 else
14111 /* Copy the list of befriending classes. */
14115 {
14119 }
14122 {
14126 /* If this is an instantiation of a member template, clone it.
14127 If it isn't, that'll be handled by
14128 clone_constructors_and_destructors. */
14131 }
14137 /* Possibly limit visibility based on template args. */
14140 {
14144 }
14156 }
14158 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
14160 static tree
14162 tree lambda_fntype)
14163 {
14164 /* We can get here when processing a member function template,
14165 member class template, or template template parameter. */
14168 tree spec;
14169 tree tmpl_args;
14170 tree full_args;
14171 tree r;
14175 {
14176 /* Template template parameter is treated here. */
14180 /* If we get a real template back, return it. This can happen in
14181 the context of most_specialized_partial_spec. */
14184 else
14185 /* The new TEMPLATE_DECL was built in
14186 reduce_template_parm_level. */
14189 }
14192 {
14193 /* We might already have an instance of this template.
14194 The ARGS are for the surrounding class type, so the
14195 full args contain the tsubst'd args for the context,
14196 plus the innermost args from the template decl. */
14200 /* Because this is a template, the arguments will still be
14201 dependent, even after substitution. If
14202 PROCESSING_TEMPLATE_DECL is not set, the dependency
14203 predicates will short-circuit. */
14211 /* If this is a default template template argument,
14212 tsubst might not have changed anything. */
14219 {
14221 /* Type partial instantiations are stored as the type by
14222 lookup_template_class_1, not here as the template. */
14225 }
14226 }
14228 /* Make a new template decl. It will be similar to the
14229 original, but will record the current template arguments.
14230 We also create a new function declaration, which is just
14231 like the old one, but points to this new template, rather
14232 than the old one. */
14237 // Build new template info linking to the original template decl.
14239 {
14242 }
14243 else
14246 /* The template parameters for this new template are all the
14247 template parameters for the old template, except the
14248 outermost level of parameters. */
14251 = current_template_parms
14253 complain);
14260 else
14261 {
14263 {
14266 }
14270 else
14272 }
14278 {
14279 /* For a partial specialization, we need to keep pointing to
14280 the primary template. */
14286 }
14288 {
14291 }
14292 else
14293 {
14296 }
14303 {
14304 /* Propagate module information from the decl. */
14307 /* If this is a constrained template, the above tsubst of
14308 inner can find the unconstrained template, which may have
14309 come from an import. This is ok, because we don't
14310 register this instantiation (see below). */
14312 || (TEMPLATE_PARMS_CONSTRAINTS
14314 }
14323 /* Record this non-type partial instantiation. */
14329 }
14331 /* True if FN is the op() for a lambda in an uninstantiated template. */
14333 bool
14335 {
14340 }
14342 /* True if FN is the substitution (via tsubst_lambda_expr) of a function for
14343 which the above is true. */
14345 bool
14347 {
14353 }
14355 /* Return the LAMBDA_EXPR from which T was ultimately regenerated.
14356 If T is not a regenerated LAMBDA_EXPR, return T. */
14358 tree
14360 {
14364 }
14366 /* We're instantiating a variable from template function TCTX. Return the
14367 corresponding current enclosing scope. We can match them up using
14368 DECL_SOURCE_LOCATION because lambdas only ever have one source location, and
14369 the DECL_SOURCE_LOCATION for a function instantiation is updated to match
14370 the template definition in regenerate_decl_from_template. */
14372 static tree
14374 {
14377 /* We shouldn't ever need to do this for other artificial functions. */
14384 }
14386 /* Substitute the ARGS into the T, which is a _DECL. Return the
14387 result of the substitution. Issue error and warning messages under
14388 control of COMPLAIN. */
14390 static tree
14392 {
14393 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
14394 location_t saved_loc;
14399 /* Set the filename and linenumber to improve error-reporting. */
14404 {
14414 {
14422 {
14423 /* If there is a local specialization that isn't a
14424 parameter pack, it means that we're doing a "simple"
14425 substitution from inside tsubst_pack_expansion. Just
14426 return the local specialization (which will be a single
14427 parm). */
14434 /* Expand the TYPE_PACK_EXPANSION that provides the types for
14435 the parameters in this function parameter pack. */
14439 {
14442 /* Zero-length parameter packs are boring. Just substitute
14443 into the chain. */
14447 }
14448 else
14449 {
14450 /* All we did was update the type. Make a note of that. */
14453 }
14454 }
14456 /* Loop through all of the parameters we'll build. When T is
14457 a function parameter pack, LEN is the number of expanded
14458 types in EXPANDED_TYPES; otherwise, LEN is 1. */
14461 {
14468 /* We're on the Ith parameter of the function parameter
14469 pack. */
14470 {
14471 /* Get the Ith type. */
14474 /* Rename the parameter to include the index. */
14477 }
14479 /* We're dealing with a normal parameter. */
14487 {
14490 else
14493 }
14504 /* Keep track of the first new parameter we
14505 generate. That's what will be returned to the
14506 caller. */
14510 /* Build a proper chain of parameters when substituting
14511 into a function parameter pack. */
14514 }
14516 /* If cp_unevaluated_operand is set, we're just looking for a
14517 single dummy parameter, so don't keep going. */
14522 /* FIRST_R contains the start of the chain we've built. */
14524 }
14528 {
14535 {
14536 /* This field is a lambda capture pack. Return a TREE_VEC of
14537 the expanded fields to instantiate_class_template_1. */
14541 {
14544 }
14545 else
14546 {
14547 /* All we did was update the type. Make a note of that. */
14550 }
14551 }
14554 {
14557 {
14561 }
14571 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
14572 number of bits. */
14578 {
14579 /* Set up DECL_TEMPLATE_INFO so that we can get at the
14580 NSDMI in perform_member_init. Still set DECL_INITIAL
14581 so that we know there is one. */
14586 }
14587 /* We don't have to set DECL_CONTEXT here; it is set by
14588 finish_member_declaration. */
14597 }
14601 }
14605 /* We reach here only for member using decls. We also need to check
14606 uses_template_parms because DECL_DEPENDENT_P is not set for a
14607 using-declaration that designates a member of the current
14608 instantiation (c++/53549). */
14611 {
14615 {
14620 {
14624 {
14627 }
14628 else
14629 {
14632 }
14634 }
14635 }
14636 else
14637 {
14643 else
14644 {
14647 }
14648 }
14649 }
14650 else
14651 {
14654 }
14659 {
14670 {
14671 /* If this is the canonical decl, we don't have to
14672 mess with instantiations, and often we can't (for
14673 typename, template type parms and such). Note that
14674 TYPE_NAME is not correct for the above test if
14675 we've copied the type for a typedef. */
14681 }
14683 /* Check to see if we already have the specialization we
14684 need. */
14690 {
14693 {
14695 complain,
14697 /* If CTX is unchanged, then T is in fact the
14698 specialization we want. That situation occurs when
14699 referencing a static data member within in its own
14700 class. We can use pointer equality, rather than
14701 same_type_p, because DECL_CONTEXT is always
14702 canonical... */
14704 /* ... unless T is a member template; in which
14705 case our caller can be willing to create a
14706 specialization of that template represented
14707 by T. */
14711 }
14714 {
14719 argvec = (coerce_innermost_template_parms
14727 }
14728 }
14729 else
14730 {
14732 /* Subsequent calls to pushdecl will fill this in. */
14734 /* A local variable. */
14736 /* Unless this is a reference to a static variable from an
14737 enclosing function, in which case we need to fill it in now. */
14739 {
14743 }
14745 }
14746 /* If we already have the specialization we need, there is
14747 nothing more to do. */
14749 {
14752 }
14754 /* Create a new node for the specialization we need. */
14756 {
14759 else
14767 {
14768 /* Mask off any template args past the variable's context so we
14769 don't replace the auto with an unrelated argument. */
14773 /* This should never happen with the new lambda instantiation
14774 model, but keep the handling just in case. */
14777 }
14779 /* Substituting the type might have recursively instantiated this
14780 same alias (c++/86171). */
14783 {
14786 }
14787 }
14790 {
14796 {
14797 /* It may seem that this case cannot occur, since:
14799 typedef void f();
14800 void g() { f x; }
14802 declares a function, not a variable. However:
14804 typedef void f();
14805 template <typename T> void g() { T t; }
14806 template void g<f>();
14808 is an attempt to declare a variable with function
14809 type. */
14811 /* R is not yet sufficiently initialized, so we
14812 just use its name. */
14815 }
14817 /* Wait until cp_finish_decl to set this again, to handle
14818 circular dependency (template/instantiate6.C). */
14823 {
14825 /* If the DECL_VALUE_EXPR is converted to the declared type,
14826 preserve the identity so that gimplify_type_sizes works. */
14833 {
14836 }
14845 else
14849 }
14853 }
14859 /* Clear out the mangled name and RTL for the instantiation. */
14865 /* The initializer must not be expanded until it is required;
14866 see [temp.inst]. */
14870 {
14876 /* Possibly limit visibility based on template args. */
14879 {
14883 }
14885 }
14888 {
14889 /* A static data member declaration is always marked
14890 external when it is declared in-class, even if an
14891 initializer is present. We mimic the non-template
14892 processing here. */
14901 }
14902 else
14903 {
14908 }
14917 /* Preserve a typedef that names a type. */
14919 {
14922 }
14925 }
14930 }
14931 #undef RETURN
14933 out:
14934 /* Restore the file and line information. */
14938 }
14940 /* Substitute into the complete parameter type list PARMS. */
14942 tree
14944 tree args,
14945 tsubst_flags_t complain,
14946 tree in_decl)
14947 {
14949 }
14951 /* Substitute into the ARG_TYPES of a function type.
14952 If END is a TREE_CHAIN, leave it and any following types
14953 un-substituted. */
14955 static tree
14957 tree args,
14958 tree end,
14959 tsubst_flags_t complain,
14960 tree in_decl)
14961 {
14970 {
14971 /* For a pack expansion, perform substitution on the
14972 entire expression. Later on, we'll handle the arguments
14973 one-by-one. */
14978 /* So that we'll spin through the parameters, one by one. */
14980 else
14981 {
14982 /* We only partially substituted into the parameter
14983 pack. Our type is TYPE_PACK_EXPANSION. */
14986 }
14987 }
14988 else
14991 /* Check if a substituted type is erroneous before substituting into
14992 the rest of the chain. */
14994 {
15001 {
15003 {
15007 }
15009 }
15010 }
15012 /* We do not substitute into default arguments here. The standard
15013 mandates that they be instantiated only when needed, which is
15014 done in build_over_call. */
15017 /* Except that we do substitute default arguments under tsubst_lambda_expr,
15018 since the new op() won't have any associated template arguments for us
15019 to refer to later. */
15030 {
15034 /* Do array-to-pointer, function-to-pointer conversion, and ignore
15035 top-level qualifiers as required. */
15039 {
15040 /* We've instantiated a template before its default arguments
15041 have been parsed. This can happen for a nested template
15042 class, and is not an error unless we require the default
15043 argument in a call of this function. */
15044 remaining_arg_types
15047 remaining_arg_types);
15048 }
15049 else
15050 remaining_arg_types
15052 }
15055 }
15057 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
15058 *not* handle the exception-specification for FNTYPE, because the
15059 initial substitution of explicitly provided template parameters
15060 during argument deduction forbids substitution into the
15061 exception-specification:
15063 [temp.deduct]
15065 All references in the function type of the function template to the
15066 corresponding template parameters are replaced by the specified tem-
15067 plate argument values. If a substitution in a template parameter or
15068 in the function type of the function template results in an invalid
15069 type, type deduction fails. [Note: The equivalent substitution in
15070 exception specifications is done only when the function is instanti-
15071 ated, at which point a program is ill-formed if the substitution
15072 results in an invalid type.] */
15074 static tree
15076 tree args,
15077 tsubst_flags_t complain,
15078 tree in_decl)
15079 {
15080 tree return_type;
15083 /* The TYPE_CONTEXT is not used for function/method types. */
15086 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
15087 failure. */
15091 {
15092 /* Substitute the argument types. */
15104 {
15105 /* DR 1207: 'this' is in scope in the trailing return type. */
15107 }
15109 /* Substitute the return type. */
15113 {
15116 }
15117 }
15118 else
15119 /* Substitute the return type. */
15124 /* DR 486 clarifies that creation of a function type with an
15125 invalid return type is a deduction failure. */
15128 {
15130 {
15133 else
15135 }
15137 }
15140 {
15141 /* Substitute the argument types. */
15146 }
15148 /* Construct a new type node and return it. */
15151 }
15153 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
15154 ARGS into that specification, and return the substituted
15155 specification. If there is no specification, return NULL_TREE. */
15157 static tree
15159 tree args,
15160 tsubst_flags_t complain,
15161 tree in_decl,
15163 {
15164 tree specs;
15165 tree new_specs;
15170 {
15171 /* A noexcept-specifier. */
15176 {
15177 /* Defer instantiation of noexcept-specifiers to avoid
15178 excessive instantiations (c++/49107). */
15181 {
15182 /* We already partially instantiated this member template,
15183 so combine the new args with the old. */
15188 }
15189 else
15190 {
15193 }
15194 }
15195 else
15196 {
15198 {
15200 args);
15202 }
15203 new_specs = tsubst_copy_and_build
15206 }
15208 /* We've instantiated a template before a noexcept-specifier
15209 contained therein has been parsed. This can happen for
15210 a nested template class:
15212 struct S {
15213 template<typename> struct B { B() noexcept(...); };
15214 struct A : B<int> { ... use B() ... };
15215 };
15217 where completing B<int> will trigger instantiating the
15218 noexcept, even though we only parse it at the end of S. */
15220 {
15223 }
15224 }
15226 {
15229 else
15231 {
15232 tree spec;
15237 {
15238 /* Expand the pack expansion type. */
15241 in_decl);
15247 else
15248 {
15249 /* We're substituting into a member template, so
15250 we got a TYPE_PACK_EXPANSION back. Add that
15251 expansion and move on. */
15255 expanded_specs,
15256 complain);
15259 }
15260 }
15263 {
15266 else
15271 complain);
15272 }
15275 }
15276 }
15278 }
15280 /* Substitute through a TREE_LIST of types or expressions, handling pack
15281 expansions. */
15283 tree
15285 {
15292 ;
15294 {
15298 }
15301 else
15309 ;
15311 {
15315 }
15318 else
15325 ;
15330 else
15341 /* Determine the number of arguments. */
15343 {
15346 }
15349 else
15353 {
15361 else
15363 }
15366 }
15368 /* Take the tree structure T and replace template parameters used
15369 therein with the argument vector ARGS. IN_DECL is an associated
15370 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
15371 Issue error and warning messages under control of COMPLAIN. Note
15372 that we must be relatively non-tolerant of extensions here, in
15373 order to preserve conformance; if we allow substitutions that
15374 should not be allowed, we may allow argument deductions that should
15375 not succeed, and therefore report ambiguous overload situations
15376 where there are none. In theory, we could allow the substitution,
15377 but indicate that it should have failed, and allow our caller to
15378 make sure that the right thing happens, but we don't try to do this
15379 yet.
15381 This function is used for dealing with types, decls and the like;
15382 for expressions, use tsubst_expr or tsubst_copy. */
15384 tree
15386 {
15412 /* Reuse typedefs. We need to do this to handle dependent attributes,
15413 such as attribute aligned. */
15416 {
15420 {
15421 /* DECL represents an alias template and we want to
15422 instantiate it. */
15426 }
15430 {
15434 }
15439 else
15440 /* The typedef is from a non-template context. */
15444 {
15446 r = cp_build_qualified_type_real
15450 }
15451 else
15452 {
15453 /* We don't have an instantiation yet, so drop the typedef. */
15458 }
15459 }
15476 {
15503 {
15509 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
15510 needed. */
15516 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
15517 with TREE_SIDE_EFFECTS that indicates this is not an integral
15518 constant expression. */
15521 {
15524 }
15527 }
15533 {
15547 {
15550 /* See through ARGUMENT_PACK_SELECT arguments. */
15553 }
15558 {
15560 /* If ARG is an argument pack, we don't actually want to
15561 perform a substitution here, because substitutions
15562 for argument packs are only done
15563 element-by-element. We can get to this point when
15564 substituting the type of a non-type template
15565 parameter pack, when that type actually contains
15566 template parameter packs from an outer template, e.g.,
15568 template<typename... Types> struct A {
15569 template<Types... Values> struct B { };
15570 }; */
15574 {
15577 /* When building concept checks for the purpose of
15578 deducing placeholders, we can end up with wildcards
15579 where types are expected. Adjust this to the deduced
15580 value. */
15588 return cp_build_qualified_type_real
15590 }
15592 {
15593 /* We are processing a type constructed from a
15594 template template parameter. */
15605 /* Consider this code:
15607 template <template <class> class Template>
15608 struct Internal {
15609 template <class Arg> using Bind = Template<Arg>;
15610 };
15612 template <template <class> class Template, class Arg>
15613 using Instantiate = Template<Arg>; //#0
15615 template <template <class> class Template,
15616 class Argument>
15617 using Bind =
15618 Instantiate<Internal<Template>::template Bind,
15619 Argument>; //#1
15621 When #1 is parsed, the
15622 BOUND_TEMPLATE_TEMPLATE_PARM representing the
15623 parameter `Template' in #0 matches the
15624 UNBOUND_CLASS_TEMPLATE representing the argument
15625 `Internal<Template>::template Bind'; We then want
15626 to assemble the type `Bind<Argument>' that can't
15627 be fully created right now, because
15628 `Internal<Template>' not being complete, the Bind
15629 template cannot be looked up in that context. So
15630 we need to "store" `Bind<Argument>' for later
15631 when the context of Bind becomes complete. Let's
15632 store that in a TYPENAME_TYPE. */
15636 argvec),
15637 typename_type,
15638 complain);
15640 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
15641 are resolving nested-types in the signature of a
15642 member function templates. Otherwise ARG is a
15643 TEMPLATE_DECL and is the real template to be
15644 instantiated. */
15652 complain);
15653 return cp_build_qualified_type_real
15655 }
15658 else
15659 /* TEMPLATE_PARM_INDEX. */
15661 }
15664 /* This can happen during the attempted tsubst'ing in
15665 unify. This means that we don't yet have any information
15666 about the template parameter in question. */
15669 /* Early in template argument deduction substitution, we don't
15670 want to reduce the level of 'auto', or it will be confused
15671 with a normal template parm in subsequent deduction.
15672 Similarly, don't reduce the level of template parameters to
15673 avoid mismatches when deducing their types. */
15677 /* If we get here, we must have been looking at a parm for a
15678 more deeply nested template. Make a new version of this
15679 template parameter, but with a lower level. */
15681 {
15686 {
15688 r = cp_build_qualified_type_real
15692 }
15699 /* Break infinite recursion when substituting the constraints
15708 /* Cache the simple case of lowering a type parameter. */
15710 else
15711 {
15722 {
15723 /* Propagate constraints on placeholders since they are
15724 only instantiated during satisfaction. */
15728 {
15733 }
15734 }
15737 /* We have reduced the level of the template
15738 template parameter, but not the levels of its
15739 template parameters, so canonical_type_parameter
15740 will not be able to find the canonical template
15741 template parameter for this level. Thus, we
15742 require structural equality checking to compare
15743 TEMPLATE_TEMPLATE_PARMs. */
15747 else
15751 {
15753 /* We might need to substitute into the types of non-type
15754 template parameters. */
15766 }
15767 }
15771 /* OK, now substitute the type of the non-type parameter. We
15772 couldn't do it earlier because it might be an auto parameter,
15773 and we wouldn't need to if we had an argument. */
15782 }
15785 }
15791 /* We should never be tsubsting a binfo. */
15795 /* A vector of template arguments. */
15801 {
15805 /* [temp.deduct]
15807 Type deduction may fail for any of the following
15808 reasons:
15810 -- Attempting to create a pointer to reference type.
15811 -- Attempting to create a reference to a reference type or
15812 a reference to void.
15814 Core issue 106 says that creating a reference to a reference
15815 during instantiation is no longer a cause for failure. We
15816 only enforce this check in strict C++98 mode. */
15820 {
15823 /* We keep track of the last time we issued this error
15824 message to avoid spewing a ton of messages during a
15825 single bad template instantiation. */
15828 {
15833 else
15836 }
15839 }
15843 {
15845 {
15848 type);
15849 else
15851 type);
15852 }
15854 }
15856 {
15860 }
15862 /* In C++0x, during template argument substitution, when there is an
15863 attempt to create a reference to a reference type, reference
15864 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
15866 "If a template-argument for a template-parameter T names a type
15867 that is a reference to a type A, an attempt to create the type
15868 'lvalue reference to cv T' creates the type 'lvalue reference to
15869 A,' while an attempt to create the type type rvalue reference to
15870 cv T' creates the type T"
15871 */
15872 r = cp_build_reference_type
15875 else
15880 /* Will this ever be needed for TYPE_..._TO values? */
15884 }
15886 {
15889 {
15890 /* [temp.deduct]
15892 Type deduction may fail for any of the following
15893 reasons:
15895 -- Attempting to create "pointer to member of T" when T
15896 is not a class type. */
15900 }
15902 {
15906 }
15908 {
15912 }
15915 {
15916 /* The type of the implicit object parameter gets its
15917 cv-qualifiers from the FUNCTION_TYPE. */
15918 tree memptr;
15919 tree method_type
15924 complain);
15925 }
15926 else
15929 complain);
15930 }
15933 {
15934 tree fntype;
15935 tree specs;
15940 /* Substitute the exception specification. */
15948 }
15950 {
15955 /* As an optimization, we avoid regenerating the array type if
15956 it will obviously be the same as T. */
15960 /* These checks should match the ones in create_array_type_for_decl.
15962 [temp.deduct]
15964 The deduction may fail for any of the following reasons:
15966 -- Attempting to create an array with an element type that
15967 is void, a function type, or a reference type, or [DR337]
15968 an abstract class type. */
15974 {
15978 }
15991 {
15994 }
15997 }
16000 {
16003 {
16009 {
16014 }
16016 }
16017 else
16029 {
16033 }
16035 {
16036 /* Normally, make_typename_type does not require that the CTX
16037 have complete type in order to allow things like:
16039 template <class T> struct S { typename S<T>::X Y; };
16041 But, such constructs have already been resolved by this
16042 point, so here CTX really should have complete type, unless
16043 it's a partial instantiation. */
16046 }
16053 {
16056 }
16059 {
16061 {
16065 else
16067 }
16069 {
16073 else
16075 }
16076 }
16078 return cp_build_qualified_type_real
16080 }
16083 {
16095 }
16098 {
16099 tree type;
16115 complain);
16116 }
16119 {
16120 tree type;
16139 else
16140 {
16144 /* In a template ~id could be either a complement expression
16145 or an unqualified-id naming a destructor; if instantiating
16146 it produces an expression, it's not an id-expression or
16147 member access. */
16150 }
16155 }
16158 {
16162 }
16181 /* We should use one of the expression tsubsts for these codes. */
16187 }
16188 }
16190 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
16191 expression on the left-hand side of the "." or "->" operator. We
16192 only do the lookup if we had a dependent BASELINK. Otherwise we
16193 adjust it onto the instantiated heirarchy. */
16195 static tree
16198 {
16210 {
16217 }
16224 {
16229 /* See maybe_dependent_member_ref. */
16231 {
16234 template_args);
16237 }
16240 /* Treat as-if non-dependent below. */
16244 complain);
16246 {
16252 }
16256 }
16257 else
16258 {
16259 /* We're going to overwrite pieces below, make a duplicate. */
16263 {
16264 /* The decl we found was from non-dependent scope, but we still need
16265 to update the binfos for the instantiated qualifying_scope. */
16269 }
16270 }
16272 /* If lookup found a single function, mark it as used at this point.
16273 (If lookup found multiple functions the one selected later by
16274 overload resolution will be marked as used at that point.) */
16276 {
16282 /* We might have instantiated an auto function. */
16284 }
16287 {
16288 /* Add back the template arguments, if present. */
16293 /* Update the conversion operator type. */
16295 }
16301 {
16303 qualifying_scope,
16304 object_type);
16306 /* We need to call adjust_result_of_qualified_name_lookup in case the
16307 destructor names a base class, but we unset BASELINK_QUALIFIED_P
16308 so that we still get virtual function binding. */
16310 }
16313 }
16315 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
16316 true if the qualified-id will be a postfix-expression in-and-of
16317 itself; false if more of the postfix-expression follows the
16318 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
16319 of "&". */
16321 static tree
16325 {
16326 tree expr;
16327 tree scope;
16328 tree name;
16330 tree template_args;
16335 /* Figure out what name to look up. */
16338 {
16347 }
16348 else
16349 {
16352 }
16354 /* Substitute into the qualifying scope. When there are no ARGS, we
16355 are just trying to simplify a non-dependent expression. In that
16356 case the qualifying scope may be dependent, and, in any case,
16357 substituting will not help. */
16360 {
16363 }
16364 else
16368 {
16375 }
16378 {
16380 {
16381 /* A BIT_NOT_EXPR is used to represent a destructor. */
16383 {
16387 }
16388 else
16391 }
16392 else
16396 {
16398 {
16402 }
16404 }
16405 }
16408 {
16412 /* Remember that there was a reference to this entity. */
16415 }
16418 {
16424 }
16427 {
16428 /* We may be repeating a check already done during parsing, but
16429 if it was well-formed and passed then, it will pass again
16430 now, and if it didn't, we wouldn't have got here. The case
16431 we want to catch is when we couldn't tell then, and can now,
16432 namely when templ prior to substitution was an
16433 identifier. */
16439 complain);
16440 else
16442 }
16448 {
16449 expr = (adjust_result_of_qualified_name_lookup
16451 expr = (finish_qualified_id_expr
16455 }
16457 /* Expressions do not generally have reference type. */
16459 /* However, if we're about to form a pointer-to-member, we just
16460 want the referenced member referenced. */
16470 }
16472 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
16473 initializer, DECL is the substituted VAR_DECL. Other arguments are as
16474 for tsubst. */
16476 static tree
16479 {
16488 {
16490 {
16492 {
16497 }
16498 }
16500 {
16501 /* If we had an initializer but it
16502 instantiated to nothing,
16503 value-initialize the object. This will
16504 only occur when the initializer was a
16505 pack expansion where the parameter packs
16506 used in that expansion were of length
16507 zero. */
16513 }
16514 }
16517 }
16519 /* If T is a reference to a dependent member of the current instantiation C and
16520 we are trying to refer to that member in a partial instantiation of C,
16521 return a SCOPE_REF; otherwise, return NULL_TREE.
16523 This can happen when forming a C++17 deduction guide, as in PR96199. */
16525 static tree
16527 tree in_decl)
16528 {
16542 }
16544 /* Like tsubst, but deals with expressions. This function just replaces
16545 template parms; to finish processing the resultant expression, use
16546 tsubst_copy_and_build or tsubst_expr. */
16548 static tree
16550 {
16552 tree r;
16560 {
16565 {
16566 /* We get here for a use of 'this' in an NSDMI. */
16570 /* This can happen for a parameter name used later in a function
16571 declaration (such as in a late-specified return type). Just
16572 make a dummy decl, since it's only used for its type. */
16575 /* Give it the template pattern as its context; its true context
16576 hasn't been instantiated yet and this is good enough for
16577 mangling. */
16579 }
16588 {
16589 tree enum_type;
16590 tree v;
16594 /* There is no need to substitute into namespace-scope
16595 enumerators. */
16598 /* If ARGS is NULL, then T is known to be non-dependent. */
16605 /* Unfortunately, we cannot just call lookup_name here.
16606 Consider:
16608 template <int I> int f() {
16609 enum E { a = I };
16610 struct S { void g() { E e = a; } };
16611 };
16613 When we instantiate f<7>::S::g(), say, lookup_name is not
16614 clever enough to find f<7>::a. */
16615 enum_type
16625 /* We didn't find the name. That should never happen; if
16626 name-lookup found it during preliminary parsing, we
16627 should find it again here during instantiation. */
16629 }
16634 {
16635 tree ctx;
16640 {
16643 {
16647 }
16649 }
16650 }
16662 {
16663 /* Local specialization will usually have been created when
16664 we instantiated the DECL_EXPR_DECL. */
16667 {
16668 /* We're in a generic lambda referencing a local extern
16669 from an outer block-scope of a non-template. */
16672 }
16673 }
16676 {
16679 {
16680 /* First try name lookup to find the instantiation. */
16683 {
16685 {
16686 /* During error-recovery we may find a non-variable,
16687 even an OVERLOAD: just bail out and avoid ICEs and
16688 duplicate diagnostics (c++/62207). */
16691 }
16693 {
16694 /* Make sure the one we found is the one we want. */
16698 }
16699 }
16703 else
16704 {
16705 /* This can happen for a variable used in a
16706 late-specified return type of a local lambda, or for a
16707 local static or constant. Building a new VAR_DECL
16708 should be OK in all those cases. */
16711 /* Avoid infinite recursion (79640). */
16714 {
16715 /* We can't call cp_finish_decl, so handle the
16716 initializer by hand. */
16731 }
16738 }
16739 /* Remember this for subsequent uses. */
16742 }
16745 }
16746 else
16770 {
16771 /* Template template argument like the following example need
16772 special treatment:
16774 template <template <class> class TT> struct C {};
16775 template <class T> struct D {
16776 template <class U> struct E {};
16777 C<E> c; // #1
16778 };
16779 D<int> d; // #2
16781 We are processing the template argument `E' in #1 for
16782 the template instantiation #2. Originally, `E' is a
16783 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
16784 have to substitute this with one having context `D<int>'. */
16788 {
16789 /* When rewriting a constructor into a deduction guide, a
16790 non-dependent name can become dependent, so memtmpl<args>
16791 becomes context::template memtmpl<args>. */
16795 }
16797 }
16798 else
16799 /* Ordinary template template argument. */
16804 {
16805 /* Handle location wrappers by substituting the wrapped node
16806 first, *then* reusing the resulting type. Doing the type
16807 first ensures that we handle template parameters and
16808 parameter pack expansions. */
16810 {
16814 }
16818 {
16819 /* Wrapper to make a C++20 template parameter object const. */
16822 {
16823 /* The template argument is not const, presumably because
16824 it is still dependent, and so not the const template parm
16825 object. */
16831 {
16832 /* Don't add a wrapper to these. */
16835 }
16836 else
16837 /* Do add a wrapper otherwise (in particular, if op is
16838 another TEMPLATE_PARM_INDEX). */
16840 }
16842 }
16843 /* force_paren_expr can also create a VIEW_CONVERT_EXPR. */
16845 {
16850 }
16851 /* We shouldn't see any other uses of these in templates. */
16853 }
16863 {
16867 }
16870 {
16876 }
16881 {
16890 /* We only want to compute the number of arguments. */
16893 else
16900 {
16902 /* Set TREE_USED for the benefit of -Wunused. */
16906 }
16914 {
16919 else
16927 else
16932 }
16933 else
16935 }
16937 {
16945 }
16946 /* Fall through */
16962 {
16969 }
16972 {
16973 tree object;
16974 tree name;
16979 {
16983 }
16986 {
16996 }
17001 in_decl);
17002 else
17005 }
17041 {
17045 }
17048 {
17053 }
17056 {
17060 }
17063 {
17071 }
17077 {
17084 }
17087 {
17094 }
17097 {
17104 }
17107 {
17108 /* Substituted template arguments */
17118 else
17120 }
17123 {
17143 }
17168 /* Fall through. */
17171 {
17174 }
17175 else
17179 /* This is handled by tsubst_copy_and_build. */
17183 {
17187 }
17190 /* We shouldn't have built any of these during initial template
17191 generation. Instead, they should be built during instantiation
17192 in response to the saved STMT_IS_FULL_EXPR_P setting. */
17196 {
17206 }
17223 {
17224 /* Instantiate any typedefs in the type. */
17229 }
17232 {
17236 {
17239 }
17241 }
17244 /* These can sometimes show up in a partial instantiation, but never
17245 involve template parms. */
17261 /* ??? There's no point in copying it for now, but maybe some
17262 day it will contain more information, such as a pointer back
17263 to the containing function, inlined copy or so. */
17272 /* We shouldn't get here, but keep going if !flag_checking. */
17276 }
17277 }
17279 /* Helper function for tsubst_omp_clauses, used for instantiation of
17280 OMP_CLAUSE_DECL of clauses. */
17282 static tree
17285 {
17289 /* Handle OpenMP iterators. */
17293 {
17294 tree ret;
17297 else
17298 {
17302 {
17317 }
17321 }
17325 }
17327 /* Handle an OpenMP array section represented as a TREE_LIST (or
17328 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
17329 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
17330 TREE_LIST. We can handle it exactly the same as an array section
17331 (purpose, value, and a chain), even though the nomenclature
17332 (low_bound, length, etc) is different. */
17334 {
17335 tree low_bound
17350 }
17353 /* Undo convert_from_reference tsubst_expr could have called. */
17359 }
17361 /* Like tsubst_copy, but specifically for OpenMP clauses. */
17363 static tree
17366 {
17372 {
17378 {
17381 {
17387 }
17388 /* FALLTHRU */
17444 {
17447 {
17454 }
17455 else
17457 }
17477 {
17480 }
17485 else
17488 in_decl,
17516 }
17519 {
17535 /* tsubst_expr on SCOPE_REF results in returning
17536 finish_non_static_data_member result. Undo that here. */
17540 {
17545 {
17549 CASE_CONVERT:
17558 /* FALLTHRU */
17562 }
17563 }
17569 {
17572 {
17575 }
17576 }
17580 }
17581 }
17585 {
17590 {
17593 }
17594 }
17596 }
17598 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
17600 static tree
17602 tree in_decl)
17603 {
17604 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
17624 {
17627 else
17628 {
17632 }
17633 }
17638 #undef RECUR
17639 }
17641 /* Used to temporarily communicate the list of #pragma omp parallel
17642 clauses to #pragma omp for instantiation if they are combined
17643 together. */
17650 /* Substitute one OMP_FOR iterator. */
17652 static bool
17657 {
17658 #define RECUR(NODE) \
17659 tsubst_expr ((NODE), args, complain, in_decl, \
17660 integral_constant_expression_p)
17672 {
17675 {
17680 {
17690 else
17692 {
17694 {
17700 }
17703 }
17704 }
17705 }
17709 }
17711 {
17712 /* We need to jump through some hoops to handle declarations in the
17713 init-statement, since we might need to handle auto deduction,
17714 but we need to keep control of initialization. */
17718 }
17719 else
17720 {
17722 {
17725 {
17729 {
17733 CASE_CONVERT:
17741 {
17744 }
17745 /* FALLTHRU */
17749 }
17750 }
17751 }
17752 else
17754 }
17756 {
17762 }
17763 else
17767 {
17773 NULL_TREE);
17774 else
17776 }
17779 {
17786 {
17791 }
17794 }
17804 {
17806 {
17807 /* Declare the variable, but don't let that initialize it. */
17812 }
17815 {
17819 {
17828 }
17829 else
17833 {
17838 }
17839 else
17843 }
17849 }
17852 {
17853 /* Declare and initialize the variable. */
17856 }
17858 {
17863 {
17865 {
17871 {
17874 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
17879 }
17882 {
17884 decl);
17886 }
17889 {
17891 decl);
17893 }
17894 else
17896 }
17899 }
17901 {
17904 ? OMP_CLAUSE_LASTPRIVATE
17909 {
17912 }
17913 }
17914 }
17917 {
17921 }
17922 else
17926 {
17937 {
17945 }
17946 else
17952 {
17958 }
17962 {
17970 }
17971 else
17977 }
17986 #undef RECUR
17987 }
17989 /* Helper function of tsubst_expr, find OMP_TEAMS inside
17990 of OMP_TARGET's body. */
17992 static tree
17994 {
17997 {
18006 }
18008 }
18010 /* Helper function for tsubst_expr. For decomposition declaration
18011 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
18012 also the corresponding decls representing the identifiers
18013 of the decomposition declaration. Return DECL if successful
18014 or error_mark_node otherwise, set *FIRST to the first decl
18015 in the list chained through DECL_CHAIN and *CNT to the number
18016 of such decls. */
18018 static tree
18022 {
18027 decl2
18032 {
18034 {
18037 }
18049 else
18050 {
18054 }
18061 {
18064 }
18065 else
18067 }
18070 }
18072 /* Return the proper local_specialization for init-capture pack DECL. */
18074 static tree
18076 {
18077 /* We handle normal pack captures by forwarding to the specialization of the
18078 captured parameter. We can't do that for pack init-captures; we need them
18079 to have their own local_specialization. We created the individual
18080 VAR_DECLs (if any) under build_capture_proxy, and we need to collect them
18081 when we process the DECL_EXPR for the pack init-capture in the template.
18082 So, how do we find them? We don't know the capture proxy pack when
18083 building the individual resulting proxies, and we don't know the
18084 individual proxies when instantiating the pack. What we have in common is
18085 the FIELD_DECL.
18087 So...when we instantiate the FIELD_DECL, we stick the result in
18088 local_specializations. Then at the DECL_EXPR we look up that result, see
18089 how many elements it has, synthesize the names, and look them up. */
18103 {
18108 }
18110 {
18115 else
18117 }
18119 }
18121 /* Like tsubst_copy for expressions, etc. but also does semantic
18122 processing. */
18124 tree
18127 {
18128 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
18129 #define RECUR(NODE) \
18130 tsubst_expr ((NODE), args, complain, in_decl, \
18131 integral_constant_expression_p)
18134 tree r;
18135 location_t loc;
18147 {
18149 {
18153 }
18184 else
18193 {
18195 tree init;
18201 {
18204 {
18208 {
18213 }
18215 }
18216 else
18217 {
18218 /* This is a non-dependent using-decl, and we'll have
18219 used the names it found during template parsing. We do
18220 not want to do the lookup again, because we might not
18221 find the things we found then. */
18224 /* We still need to push the bindings so that we can look up
18225 this name later. */
18228 }
18229 }
18232 {
18233 /* We're in tsubst_lambda_expr, we've already inserted a new
18234 capture proxy, so look it up and register it. */
18235 tree inst;
18237 {
18241 }
18243 {
18244 inst = (retrieve_local_specialization
18248 }
18249 else
18254 }
18261 /* Don't copy the old closure; we'll create a new one in
18262 tsubst_lambda_expr. */
18264 else
18265 {
18269 {
18270 /* By marking the declaration as instantiated, we avoid
18271 trying to instantiate it. Since instantiate_decl can't
18272 handle local variables, and since we've already done
18273 all that needs to be done, that's the right thing to
18274 do. */
18279 /* Anonymous aggregates are a special case. */
18282 {
18285 {
18289 }
18291 }
18296 {
18304 }
18305 else
18306 {
18323 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
18329 /* In a non-template function, VLA type declarations are
18330 handled in grokdeclarator; for templates, handle them
18331 now. */
18335 {
18339 asmspec_tree
18343 }
18349 }
18350 }
18351 }
18354 }
18364 {
18368 }
18373 {
18374 /* Construct another range_for, if this is not a final
18375 substitution (for inside a generic lambda of a
18376 template). Otherwise convert to a regular for. */
18378 stmt = (processing_template_decl
18395 {
18401 }
18402 else
18403 {
18409 }
18415 }
18422 {
18426 }
18432 {
18436 }
18452 {
18453 /* We're partially instantiating a generic lambda, but the condition
18454 of the constexpr if is still dependent. Don't substitute into the
18455 branches now, just remember the template arguments. */
18463 }
18467 {
18472 }
18473 else
18474 {
18482 }
18488 {
18498 }
18506 else
18514 else
18535 {
18541 {
18546 }
18547 }
18551 {
18553 tree label;
18560 }
18566 /* Computed goto's must be tsubst'd into. On the other hand,
18567 non-computed gotos must not be; the identifier in question
18568 will have no binding. */
18570 else
18576 {
18593 }
18598 {
18603 }
18604 else
18605 {
18610 else
18617 else
18623 else
18625 }
18629 {
18633 {
18635 /* Prevent instantiate_decl from trying to instantiate
18636 this variable. We've already done all that needs to be
18637 done. */
18640 }
18645 }
18651 {
18652 /* Local classes are not independent templates; they are
18653 instantiated along with their containing function. And this
18654 way we don't have to deal with pushing out of one local class
18655 to instantiate a member of another local class. */
18656 /* Closures are handled by the LAMBDA_EXPR. */
18666 }
18670 {
18671 tree condition;
18674 condition =
18676 args,
18685 }
18692 in_decl);
18714 {
18721 }
18737 {
18751 in_decl);
18753 {
18760 }
18771 any_range_for
18775 integral_constant_expression_p);
18779 {
18788 }
18789 else
18794 else
18801 else
18802 {
18810 }
18813 t));
18815 }
18820 /* FALLTHRU */
18829 in_decl);
18831 {
18836 }
18837 else
18838 {
18842 }
18847 {
18849 "%<#pragma omp critical%> with %<hint%> clause requires "
18852 }
18863 {
18866 {
18871 }
18872 else
18873 {
18877 }
18879 }
18880 else
18882 OMP_CLAUSE_DEPEND_SOURCE,
18891 in_decl);
18902 {
18905 {
18906 /* For combined target teams, ensure the num_teams and
18907 thread_limit clause expressions are evaluated on the host,
18908 before entering the target construct. */
18909 tree c;
18915 {
18924 OMP_CLAUSE_FIRSTPRIVATE);
18928 }
18929 }
18930 }
18978 /* FALLTHRU */
18996 {
19001 {
19004 }
19010 }
19011 else
19012 {
19019 {
19022 }
19025 {
19030 {
19033 }
19039 }
19040 else
19041 {
19045 }
19048 }
19052 {
19058 {
19062 {
19067 }
19071 }
19072 else
19073 {
19078 }
19079 }
19083 {
19087 }
19100 /* If the first operand was a statement, we're done with it. */
19104 complain));
19121 integral_constant_expression_p));
19122 }
19125 out:
19128 #undef RECUR
19129 #undef RETURN
19130 }
19132 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
19133 function. For description of the body see comment above
19134 cp_parser_omp_declare_reduction_exprs. */
19136 static void
19138 {
19144 tree_stmt_iterator tsi;
19155 {
19162 /* tsubsting a local var_decl leaves DECL_CONTEXT null, as we
19163 expect to be pushing it. */
19176 }
19178 {
19198 }
19199 }
19201 /* T is a postfix-expression that is not being used in a function
19202 call. Return the substituted version of T. */
19204 static tree
19206 tsubst_flags_t complain,
19207 tree in_decl)
19208 {
19212 else
19218 }
19220 /* Subroutine of tsubst_lambda_expr: add the FIELD/INIT capture pair to the
19221 LAMBDA_EXPR_CAPTURE_LIST passed in LIST. Do deduction for a previously
19222 dependent init-capture. */
19224 static void
19226 tsubst_flags_t complain)
19227 {
19229 {
19232 {
19236 }
19243 }
19245 }
19247 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
19248 instantiation context. Instantiating a pack expansion containing a lambda
19249 might result in multiple lambdas all based on the same lambda in the
19250 template. */
19252 tree
19254 {
19268 else
19279 {
19284 else
19297 {
19298 /* For a VLA, simply tsubsting the field type won't work, we need to
19299 go through add_capture again. XXX do we want to do this for all
19300 captures? */
19301 tree name = (get_identifier
19309 }
19316 {
19317 /* Remember these for when we've pushed local_specializations. */
19320 }
19326 {
19334 complain);
19335 }
19336 else
19337 {
19339 complain);
19343 }
19344 }
19351 /* A lambda in a default argument outside a class gets no
19352 LAMBDA_EXPR_EXTRA_SCOPE, as specified by the ABI. But
19353 tsubst_default_argument calls start_lambda_scope, so we need to
19354 specifically ignore it here, and use the global scope. */
19356 else
19359 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
19377 else
19378 {
19379 /* The body of a lambda-expression is not a subexpression of the
19380 enclosing expression. Parms are to have DECL_CHAIN tsubsted,
19381 which would be skipped if cp_unevaluated_operand. */
19382 cp_evaluated ev;
19384 /* Fix the type of 'this'. */
19390 {
19393 {
19396 }
19399 }
19400 else
19401 {
19405 {
19408 }
19410 }
19412 /* Let finish_function set this. */
19418 else
19419 /* Still increment function_depth so that we don't GC in the
19420 middle of an expression. */
19430 /* Now record them for lookup_init_capture_pack. */
19433 {
19437 }
19443 {
19444 /* We might not partially instantiate some parts of the function, so
19445 copy these flags from the original template. */
19451 }
19453 /* [temp.deduct] A lambda-expression appearing in a function type or a
19454 template parameter is not considered part of the immediate context for
19455 the purposes of template argument deduction. */
19460 /* We already have a body block from start_lambda_function, we don't
19461 need another to confuse NRV (91217). */
19472 else
19475 /* The capture list was built up in reverse order; fix that now. */
19482 }
19484 out:
19490 }
19492 /* Like tsubst but deals with expressions and performs semantic
19493 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)" or
19494 "F<TARGS> (ARGS)". */
19496 tree
19498 tree args,
19499 tsubst_flags_t complain,
19500 tree in_decl,
19503 {
19504 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
19505 #define RECUR(NODE) \
19506 tsubst_copy_and_build (NODE, args, complain, in_decl, \
19508 integral_constant_expression_p)
19511 location_t save_loc;
19520 /* N3276 decltype magic only applies to calls at the top level or on the
19521 right side of a comma. */
19526 {
19529 /* Fall through. */
19531 {
19532 tree decl;
19533 cp_id_kind idk;
19538 {
19541 }
19543 /* Look up the name. */
19546 /* By convention, expressions use ERROR_MARK_NODE to indicate
19547 failure, not NULL_TREE. */
19553 integral_constant_expression_p,
19561 input_location);
19565 {
19569 }
19571 }
19574 {
19575 tree object;
19578 function_p,
19579 integral_constant_expression_p);
19588 {
19593 }
19596 {
19603 /* If we built a function concept check, return the underlying
19604 template-id. So we can evaluate it as a function call. */
19609 }
19612 {
19614 complain);
19617 }
19620 {
19623 }
19624 else
19633 {
19634 /* C++20 P0846: we can encounter an IDENTIFIER_NODE here when
19635 name lookup found nothing when parsing the template name. */
19638 }
19639 else
19641 }
19644 {
19648 {
19649 /* A type conversion to reference type will be enclosed in
19650 such an indirect ref, but the substitution of the cast
19651 will have also added such an indirect ref. */
19653 }
19654 else
19662 }
19665 {
19669 }
19672 {
19676 {
19681 }
19683 /* We'll pass this to convert_nontype_argument again, we don't need
19684 to actually perform any conversion here. */
19692 flags));
19693 }
19696 {
19702 }
19709 {
19710 tree type;
19716 {
19721 }
19729 {
19749 }
19752 }
19755 {
19759 }
19782 /* convert_like should have created an IMPLICIT_CONV_EXPR. */
19793 else
19795 in_decl);
19829 {
19830 /* If either OP0 or OP1 was value- or type-dependent, suppress
19831 warnings that depend on the range of the types involved. */
19841 };
19851 tree r = build_x_binary_op
19853 op0,
19855 ? ERROR_MARK
19857 op1,
19859 ? ERROR_MARK
19867 }
19870 {
19878 }
19899 /* Fall through */
19902 {
19903 tree r;
19911 {
19912 /* When there are no ARGS, we are trying to evaluate a
19913 non-dependent expression from the parser. Trying to do
19914 the substitutions may not work. */
19917 }
19918 else
19919 {
19924 else
19927 /*integral_constant_expression_p=*/
19931 }
19936 else
19941 {
19943 {
19945 {
19949 }
19950 else
19954 }
19956 }
19958 }
19961 {
19971 }
19987 {
19991 tree r = build_x_modify_expr
19994 /* TREE_NO_WARNING must be set if either the expression was
19995 parenthesized or it uses an operator such as >>= rather
19996 than plain assignment. In the former case, it was already
19997 set and must be copied. In the latter case,
19998 build_x_modify_expr sets it and it must not be reset
19999 here. */
20004 }
20009 /* Remember that there was a reference to this entity. */
20016 {
20021 tree ret;
20028 else
20029 {
20033 }
20035 /* If there was an initializer in the original tree, but it
20036 instantiated to an empty list, then we should pass a
20037 non-NULL empty vector to tell build_new that it was an
20038 empty initializer() rather than no initializer. This can
20039 only happen when the initializer is a pack expansion whose
20040 parameter packs are of length zero. */
20045 else
20046 {
20050 else
20051 {
20054 }
20055 }
20057 /* Avoid passing an enclosing decl to valid_array_size_p. */
20064 complain);
20072 }
20075 {
20081 complain));
20082 }
20085 {
20089 integral_constant_expression_p);
20091 op0,
20094 }
20097 {
20098 tree function;
20102 tree ret;
20105 /* Internal function with no arguments. */
20109 /* When we parsed the expression, we determined whether or
20110 not Koenig lookup should be performed. */
20113 {
20116 }
20118 {
20123 }
20125 {
20126 /* Do nothing; calling tsubst_copy_and_build on an identifier
20127 would incorrectly perform unqualified lookup again.
20129 Note that we can also have an IDENTIFIER_NODE if the earlier
20130 unqualified lookup found a member function; in that case
20131 koenig_p will be false and we do want to do the lookup
20132 again to find the instantiated member function.
20134 FIXME but doing that causes c++/15272, so we need to stop
20135 using IDENTIFIER_NODE in that situation. */
20137 }
20138 else
20139 {
20141 {
20147 }
20148 else
20153 /* Avoid error about taking the address of a constructor. */
20158 /* When KOENIG_P, we don't want to mark_used the callee before
20159 augmenting the overload set via ADL, so during this initial
20160 substitution we disable mark_used by setting tf_conv (68942). */
20163 in_decl,
20165 integral_constant_expression_p);
20169 }
20172 releasing_vec call_args;
20174 {
20179 else
20180 {
20181 /* Expand the pack expansion and push each entry onto
20182 CALL_ARGS. */
20185 {
20190 {
20195 }
20196 }
20197 else
20198 {
20199 /* A partial substitution. Add one entry. */
20201 }
20202 }
20203 }
20205 /* Stripped-down processing for a call in a thunk. Specifically, in
20206 the thunk template for a generic lambda. */
20208 {
20209 /* Now that we've expanded any packs, the number of call args
20210 might be different. */
20214 {
20221 }
20222 /* We aren't going to do normal overload resolution, so force the
20223 template-id to resolve. */
20226 {
20227 /* In a thunk, pass through args directly, without any
20228 conversions. */
20233 }
20235 {
20236 /* If there are no other args, just push 'this'. */
20239 else
20240 {
20241 /* Otherwise, shift the other args over to make room. */
20247 }
20248 }
20251 /* The thunk location is not interesting. */
20258 }
20260 /* We do not perform argument-dependent lookup if normal
20261 lookup finds a non-function, in accordance with the
20262 resolution of DR 218. */
20265 /* If lookup found a member function, the Koenig lookup is
20266 not appropriate, even if an unqualified-name was used
20267 to denote the function. */
20270 /* C++20 P0846: Lookup found nothing. */
20273 /* Only do this when substitution turns a dependent call
20274 into a non-dependent call. */
20284 {
20288 {
20289 /* For backwards compatibility and good diagnostics, try
20290 the unqualified lookup again if we aren't in SFINAE
20291 context. */
20292 tree unq = (tsubst_copy_and_build
20294 integral_constant_expression_p));
20299 {
20300 /* In a lambda fn, we have to be careful to not
20301 introduce new this captures. Legacy code can't
20302 be using lambdas anyway, so it's ok to be
20303 stricter. */
20308 "and no declarations were found by "
20309 "argument-dependent lookup at the point "
20316 else
20320 {
20331 {
20334 "declarations in dependent base %qT are "
20340 else
20344 }
20345 else
20347 "%qD declared here, later in the "
20351 }
20354 }
20355 }
20357 {
20361 }
20362 }
20364 /* Remember that there was a reference to this entity. */
20370 /* Put back tf_decltype for the actual call. */
20375 {
20379 {
20381 "wrong number of arguments to "
20384 }
20385 else
20393 {
20395 "wrong number of arguments to "
20399 }
20403 complain);
20409 {
20411 complain);
20415 }
20418 /* Unsupported internal function with arguments. */
20420 }
20425 complain);
20427 {
20442 complain);
20443 else
20444 ret = (build_new_method_call
20449 complain));
20450 }
20452 {
20453 /* FUNCTION is a template-id referring to a concept definition. */
20458 /* Calls to standard and variable concepts should have been
20459 previously diagnosed. */
20462 /* Ensure the result is wrapped as a call expression. */
20464 }
20465 else
20468 koenig_p,
20469 complain);
20472 {
20477 {
20482 }
20483 }
20486 }
20489 {
20496 {
20498 {
20503 }
20504 else
20505 {
20510 }
20512 }
20513 else
20514 {
20517 }
20522 }
20525 {
20530 input_location));
20531 }
20537 {
20538 tree object;
20539 tree object_type;
20540 tree member;
20541 tree r;
20545 /* Remember that there was a reference to this entity. */
20556 else
20562 {
20567 }
20571 {
20573 {
20578 {
20581 }
20583 {
20588 }
20589 }
20590 }
20593 {
20594 /* Lookup the template functions now that we know what the
20595 scope is. */
20602 {
20605 args);
20606 member = (adjust_result_of_qualified_name_lookup
20608 object_type));
20609 }
20610 else
20611 {
20613 input_location);
20615 }
20616 }
20620 {
20622 {
20626 else
20629 }
20631 }
20635 complain);
20639 }
20646 {
20654 tree r;
20659 /* We do not want to process the index of aggregate
20660 initializers as they are identifier nodes which will be
20661 looked up by digest_init. */
20665 {
20668 }
20673 {
20675 /* An identifier index is looked up in the type
20676 being initialized, not the current scope. */
20681 {
20682 /* Substitute into the pack expansion. */
20684 in_decl);
20688 ;
20690 /* Just move the argument into place. */
20692 else
20693 {
20694 /* Update the length of the final CONSTRUCTOR
20695 arguments vector, and note that we will need to
20696 copy.*/
20699 }
20700 }
20701 else
20703 }
20706 {
20711 {
20713 {
20718 }
20719 else
20721 }
20722 }
20730 {
20735 }
20739 }
20742 {
20745 {
20748 }
20749 else
20750 {
20753 }
20754 }
20759 /* Fall through */
20762 {
20764 /* ??? We're doing a subset of finish_id_expression here. */
20766 /* Replace an evaluated use of the thread_local variable with
20767 a call to its wrapper. */
20773 /* If the original type was a reference, we'll be wrapped in
20774 the appropriate INDIRECT_REF. */
20777 }
20780 {
20784 }
20787 {
20788 tree object_ptr
20795 }
20802 {
20809 }
20812 {
20818 integral_constant_expression_p);
20822 /* If the resulting list of expression statement is empty,
20823 fold it further into void_node. */
20828 }
20831 {
20833 {
20834 /* We don't have a full set of template arguments yet; don't touch
20835 the lambda at all. */
20838 }
20842 }
20845 /* We can get here for a constant initializer of non-dependent type.
20846 FIXME stop folding in cp_parser_initializer_clause. */
20847 {
20849 complain);
20851 }
20855 integral_constant_expression_p));
20861 {
20866 complain));
20867 }
20870 {
20873 }
20876 /* No need to substitute further, a RANGE_EXPR will always be built
20877 with constant operands. */
20883 /* We need to do this here as well as in tsubst_copy so we get the
20884 other tsubst_copy_and_build semantics for a PARM_DECL operand. */
20887 /* fallthrough. */
20890 /* Handle Objective-C++ constructs, if appropriate. */
20891 {
20892 tree subst
20897 }
20899 }
20901 #undef RECUR
20902 #undef RETURN
20903 out:
20906 }
20908 /* Verify that the instantiated ARGS are valid. For type arguments,
20909 make sure that the type's linkage is ok. For non-type arguments,
20910 make sure they are constants if they are integral or enumerations.
20911 Emit an error under control of COMPLAIN, and return TRUE on error. */
20913 static bool
20915 {
20919 {
20929 }
20931 {
20932 /* [basic.link]: A name with no linkage (notably, the name
20933 of a class or enumeration declared in a local scope)
20934 shall not be used to declare an entity with linkage.
20935 This implies that names with no linkage cannot be used as
20936 template arguments
20938 DR 757 relaxes this restriction for C++0x. */
20943 {
20944 /* DR 488 makes use of a type with no linkage cause
20945 type deduction to fail. */
20947 {
20950 else
20953 }
20955 }
20956 /* In order to avoid all sorts of complications, we do not
20957 allow variably-modified types as template arguments. */
20959 {
20963 }
20964 }
20965 /* Class template and alias template arguments should be OK. */
20967 ;
20968 /* A non-type argument of integral or enumerated type must be a
20969 constant. */
20974 {
20978 }
20980 }
20982 static bool
20984 {
20989 {
20992 }
20996 }
20998 /* We're out of SFINAE context now, so generate diagnostics for the access
20999 errors we saw earlier when instantiating D from TMPL and ARGS. */
21001 static void
21003 {
21015 }
21017 /* Instantiate the indicated variable, function, or alias template TMPL with
21018 the template arguments in TARG_PTR. */
21020 static tree
21022 {
21024 tree fndecl;
21025 tree gen_tmpl;
21026 tree spec;
21037 /* If this function is a clone, handle it specially. */
21039 {
21040 tree spec;
21041 tree clone;
21043 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
21044 DECL_CLONED_FUNCTION. */
21050 /* Look for the clone. */
21054 /* We should always have found the clone by now. */
21057 }
21062 /* Check to see if we already have this specialization. */
21066 /* targ_ptr only has the innermost template args, so add the outer ones
21067 from tmpl, which could be either a partial instantiation or gen_tmpl (in
21068 the case of a non-dependent call within a template definition). */
21069 targ_ptr = (add_outermost_template_args
21071 targ_ptr));
21073 /* It would be nice to avoid hashing here and then again in tsubst_decl,
21074 but it doesn't seem to be on the hot path. */
21078 || ((fndecl
21084 {
21086 {
21090 }
21092 }
21095 complain))
21098 /* We are building a FUNCTION_DECL, during which the access of its
21099 parameters and return types have to be checked. However this
21100 FUNCTION_DECL which is the desired context for access checking
21101 is not built yet. We solve this chicken-and-egg problem by
21102 deferring all checks until we have the FUNCTION_DECL. */
21105 /* Instantiation of the function happens in the context of the function
21106 template, not the context of the overload resolution we're doing. */
21108 /* If there are dependent arguments, e.g. because we're doing partial
21109 ordering, make sure processing_template_decl stays set. */
21113 {
21117 }
21123 {
21124 /* We need to determine if we're using a partial or explicit
21125 specialization now, because the type of the variable could be
21126 different. */
21132 {
21137 }
21138 }
21140 /* Substitute template parameters to obtain the specialization. */
21148 {
21151 }
21153 /* The DECL_TI_TEMPLATE should always be the immediate parent
21154 template, not the most general template. */
21160 /* Now we know the specialization, compute access previously
21161 deferred. Do no access control for inheriting constructors,
21162 as we already checked access for the inherited constructor. */
21165 {
21170 }
21173 /* If we've just instantiated the main entry point for a function,
21174 instantiate all the alternate entry points as well. We do this
21175 by cloning the instantiation of the main entry point, not by
21176 instantiating the template clones. */
21182 {
21184 {
21185 /* Remember to reinstantiate when we're out of SFINAE so the user
21186 can see the errors. */
21188 }
21190 }
21192 }
21194 /* Wrapper for instantiate_template_1. */
21196 tree
21198 {
21199 tree ret;
21204 }
21206 /* Instantiate the alias template TMPL with ARGS. Also push a template
21207 instantiation level, which instantiate_template doesn't do because
21208 functions and variables have sufficient context established by the
21209 callers. */
21211 static tree
21213 {
21217 args =
21223 /* FIXME check for satisfaction in check_instantiated_args. */
21227 {
21229 {
21230 auto_diagnostic_group d;
21233 }
21235 }
21243 {
21244 /* An alias template specialization can be dependent
21245 even if its underlying type is not. */
21248 /* Sometimes a dependent alias spec is equivalent to its expansion,
21249 sometimes not. So always use structural_comptypes. */
21251 }
21254 }
21256 /* PARM is a template parameter pack for FN. Returns true iff
21257 PARM is used in a deducible way in the argument list of FN. */
21259 static bool
21261 {
21264 {
21266 tree packs;
21272 {
21273 /* The template parameter pack is used in a function parameter
21274 pack. If this is the end of the parameter list, the
21275 template parameter pack is deducible. */
21278 else
21279 /* Otherwise, not. Well, it could be deduced from
21280 a non-pack parameter, but doing so would end up with
21281 a deduction mismatch, so don't bother. */
21283 }
21284 }
21285 /* The template parameter pack isn't used in any function parameter
21286 packs, but it might be used deeper, e.g. tuple<Args...>. */
21288 }
21290 /* Subroutine of fn_type_unification: check non-dependent parms for
21291 convertibility. */
21293 static int
21297 {
21298 /* Non-constructor methods need to leave a conversion for 'this', which
21299 isn't included in nargs here. */
21305 {
21311 /* For a function parameter pack that occurs at the end of the
21312 parameter-declaration-list, the type A of each remaining
21313 argument of the call is compared with the type P of the
21314 declarator-id of the function parameter pack. */
21320 /* For a function parameter pack that does not occur at the
21321 end of the parameter-declaration-list, the type of the
21322 parameter pack is a non-deduced context. */
21326 {
21334 }
21337 }
21340 }
21342 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
21343 NARGS elements of the arguments that are being used when calling
21344 it. TARGS is a vector into which the deduced template arguments
21345 are placed.
21347 Returns either a FUNCTION_DECL for the matching specialization of FN or
21348 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
21349 true, diagnostics will be printed to explain why it failed.
21351 If FN is a conversion operator, or we are trying to produce a specific
21352 specialization, RETURN_TYPE is the return type desired.
21354 The EXPLICIT_TARGS are explicit template arguments provided via a
21355 template-id.
21357 The parameter STRICT is one of:
21359 DEDUCE_CALL:
21360 We are deducing arguments for a function call, as in
21361 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
21362 deducing arguments for a call to the result of a conversion
21363 function template, as in [over.call.object].
21365 DEDUCE_CONV:
21366 We are deducing arguments for a conversion function, as in
21367 [temp.deduct.conv].
21369 DEDUCE_EXACT:
21370 We are deducing arguments when doing an explicit instantiation
21371 as in [temp.explicit], when determining an explicit specialization
21372 as in [temp.expl.spec], or when taking the address of a function
21373 template, as in [temp.deduct.funcaddr]. */
21375 tree
21377 tree explicit_targs,
21378 tree targs,
21381 tree return_type,
21382 unification_kind_t strict,
21387 {
21388 tree parms;
21389 tree fntype;
21394 /* type_unification_real will pass back any access checks from default
21395 template argument substitution. */
21397 /* We don't have all the template args yet. */
21410 full_targs = (add_outermost_template_args
21412 targs));
21417 /* In C++0x, it's possible to have a function template whose type depends
21418 on itself recursively. This is most obvious with decltype, but can also
21419 occur with enumeration scope (c++/48969). So we need to catch infinite
21420 recursion and reject the substitution at deduction time; this function
21421 will return error_mark_node for any repeated substitution.
21423 This also catches excessive recursion such as when f<N> depends on
21424 f<N-1> across all integers, and returns error_mark_node for all the
21425 substitutions back up to the initial one.
21427 This is, of course, not reentrant. */
21436 {
21437 /* [temp.deduct]
21439 The specified template arguments must match the template
21440 parameters in kind (i.e., type, nontype, template), and there
21441 must not be more arguments than there are parameters;
21442 otherwise type deduction fails.
21444 Nontype arguments must match the types of the corresponding
21445 nontype template parameters, or must be convertible to the
21446 types of the corresponding nontype parameters as specified in
21447 _temp.arg.nontype_, otherwise type deduction fails.
21449 All references in the function type of the function template
21450 to the corresponding template parameters are replaced by the
21451 specified template argument values. If a substitution in a
21452 template parameter or in the function type of the function
21453 template results in an invalid type, type deduction fails. */
21464 explicit_targs);
21466 /* Adjust any explicit template arguments before entering the
21467 substitution context. */
21468 explicit_targs
21476 /* Substitute the explicit args into the function type. This is
21477 necessary so that, for instance, explicitly declared function
21478 arguments can match null pointed constants. If we were given
21479 an incomplete set of explicit args, we must not do semantic
21480 processing during substitution as we could create partial
21481 instantiations. */
21483 {
21488 /* Dig out the actual parm. */
21491 {
21494 }
21496 {
21499 }
21502 /* No explicit argument for this template parameter. */
21505 {
21506 /* Mark the argument pack as "incomplete". We could
21507 still deduce more arguments during unification.
21508 We remove this mark in type_unification_real. */
21513 /* We have some incomplete argument packs. */
21515 }
21516 }
21519 {
21521 {
21524 }
21527 /* Ignore any access checks; we'll see them again in
21528 instantiate_template and they might have the wrong
21529 access path at this point. */
21540 }
21542 /* Place the explicitly specified arguments in TARGS. */
21548 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
21550 }
21553 {
21559 }
21564 /* Never do unification on the 'this' parameter. */
21568 {
21569 /* We're deducing for a call to the result of a template conversion
21570 function. The parms we really want are in return_type. */
21574 }
21576 {
21578 }
21580 /* We allow incomplete unification without an error message here
21581 because the standard doesn't seem to explicitly prohibit it. Our
21582 callers must be ready to deal with unification failures in any
21583 event. */
21585 /* If we aren't explaining yet, push tinst context so we can see where
21586 any errors (e.g. from class instantiations triggered by instantiation
21587 of default template arguments) come from. If we are explaining, this
21588 context is redundant. */
21590 {
21593 }
21603 /* Now that we have bindings for all of the template arguments,
21604 ensure that the arguments deduced for the template template
21605 parameters have compatible template parameter lists. We cannot
21606 check this property before we have deduced all template
21607 arguments, because the template parameter types of a template
21608 template parameter might depend on prior template parameters
21609 deduced after the template template parameter. The following
21610 ill-formed example illustrates this issue:
21612 template<typename T, template<T> class C> void f(C<5>, T);
21614 template<int N> struct X {};
21616 void g() {
21617 f(X<5>(), 5l); // error: template argument deduction fails
21618 }
21620 The template parameter list of 'C' depends on the template type
21621 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
21622 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
21623 time that we deduce 'C'. */
21626 {
21629 }
21631 deduced:
21633 /* CWG2369: Check satisfaction before non-deducible conversions. */
21635 {
21639 }
21641 /* DR 1391: All parameters have args, now check non-dependent parms for
21642 convertibility. We don't do this if all args were explicitly specified,
21643 as the standard says that we substitute explicit args immediately. */
21649 /* All is well so far. Now, check:
21651 [temp.deduct]
21653 When all template arguments have been deduced, all uses of
21654 template parameters in nondeduced contexts are replaced with
21655 the corresponding deduced argument values. If the
21656 substitution results in an invalid type, as described above,
21657 type deduction fails. */
21659 {
21662 }
21664 /* Also collect access checks from the instantiation. */
21677 /* Now perform any access checks encountered during substitution. */
21684 /* If we're looking for an exact match, check that what we got
21685 is indeed an exact match. It might not be if some template
21686 parameters are used in non-deduced contexts. But don't check
21687 for an exact match if we have dependent template arguments;
21688 in that case we're doing partial ordering, and we already know
21689 that we have two candidates that will provide the actual type. */
21691 {
21695 tree sarg
21701 {
21705 }
21706 }
21708 /* After doing deduction with the inherited constructor, actually return an
21709 instantiation of the inheriting constructor. */
21715 fail:
21718 {
21720 /* Reset once we're all the way out. */
21722 }
21725 }
21727 /* Adjust types before performing type deduction, as described in
21728 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
21729 sections are symmetric. PARM is the type of a function parameter
21730 or the return type of the conversion function. ARG is the type of
21731 the argument passed to the call, or the type of the value
21732 initialized with the result of the conversion function.
21733 ARG_EXPR is the original argument expression, which may be null. */
21735 static int
21739 tree arg_expr)
21740 {
21744 {
21749 /* Swap PARM and ARG throughout the remainder of this
21750 function; the handling is precisely symmetric since PARM
21751 will initialize ARG rather than vice versa. */
21756 /* Core issue #873: Do the DR606 thing (see below) for these cases,
21757 too, but here handle it by stripping the reference from PARM
21758 rather than by adding it to ARG. */
21766 /* Nothing else to do in this case. */
21771 }
21774 {
21775 /* [temp.deduct.call]
21777 If P is not a reference type:
21779 --If A is an array type, the pointer type produced by the
21780 array-to-pointer standard conversion (_conv.array_) is
21781 used in place of A for type deduction; otherwise,
21783 --If A is a function type, the pointer type produced by
21784 the function-to-pointer standard conversion
21785 (_conv.func_) is used in place of A for type deduction;
21786 otherwise,
21788 --If A is a cv-qualified type, the top level
21789 cv-qualifiers of A's type are ignored for type
21790 deduction. */
21795 else
21797 }
21799 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
21800 reference to a cv-unqualified template parameter that does not represent a
21801 template parameter of a class template (during class template argument
21802 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
21803 an lvalue, the type "lvalue reference to A" is used in place of A for type
21804 deduction. */
21811 /* try_one_overload doesn't provide an arg_expr, but
21812 functions are always lvalues. */
21816 /* [temp.deduct.call]
21818 If P is a cv-qualified type, the top level cv-qualifiers
21819 of P's type are ignored for type deduction. If P is a
21820 reference type, the type referred to by P is used for
21821 type deduction. */
21824 {
21827 }
21829 /* DR 322. For conversion deduction, remove a reference type on parm
21830 too (which has been swapped into ARG). */
21835 }
21837 /* Subroutine of fn_type_unification. PARM is a function parameter of a
21838 template which doesn't contain any deducible template parameters; check if
21839 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
21840 unify_one_argument. */
21842 static int
21846 {
21847 tree type;
21851 else
21859 {
21862 }
21864 {
21868 /* Avoid recalculating this in add_function_candidate. */
21869 ok = (*conv_p
21871 else
21875 }
21879 else
21881 }
21885 /* Returns true iff the expression EXPR is one from which a template
21886 argument can be deduced. In other words, if it's an undecorated
21887 use of a template non-type parameter. */
21889 static bool
21891 {
21892 /* Strip implicit conversions and implicit INDIRECT_REFs. */
21898 }
21900 /* Returns true iff the array domain DOMAIN uses a template parameter in a
21901 deducible way; that is, if it has a max value of <PARM> - 1. */
21903 static bool
21905 {
21914 }
21916 /* Returns true iff the template arguments ARGS use a template parameter
21917 in a deducible way. */
21919 static bool
21921 {
21923 {
21928 else
21929 {
21936 else
21938 }
21941 }
21943 }
21945 /* Returns true iff TYPE contains any deducible references to template
21946 parameters, as per 14.8.2.5. */
21948 static bool
21950 {
21954 /* T
21955 cv-list T
21956 TT<T>
21957 TT<i>
21958 TT<> */
21963 /* T*
21964 T&
21965 T&& */
21969 /* T[integer-constant ]
21970 type [i] */
21975 /* T type ::*
21976 type T::*
21977 T T::*
21978 T (type ::*)()
21979 type (T::*)()
21980 type (type ::*)(T)
21981 type (T::*)(T)
21982 T (type ::*)(T)
21983 T (T::*)()
21984 T (T::*)(T) */
21987 || (uses_deducible_template_parms
21990 /* template-name <T> (where template-name refers to a class template)
21991 template-name <i> (where template-name refers to a class template) */
21998 /* type (T)
21999 T()
22000 T(T) */
22002 {
22011 }
22014 }
22016 /* Subroutine of type_unification_real and unify_pack_expansion to
22017 handle unification of a single P/A pair. Parameters are as
22018 for those functions. */
22020 static int
22024 {
22031 /* We can't deduce anything from this, but we might get all the
22032 template args from other function args. */
22035 /* Implicit conversions (Clause 4) will be performed on a function
22036 argument to convert it to the type of the corresponding function
22037 parameter if the parameter type contains no template-parameters that
22038 participate in template argument deduction. */
22041 /* For function parameters with no deducible template parameters,
22042 just return. We'll check non-dependent conversions later. */
22046 {
22048 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
22049 | UNIFY_ALLOW_MORE_CV_QUAL
22063 }
22065 /* We only do these transformations if this is the top-level
22066 parameter_type_list in a call or declaration matching; in other
22067 situations (nested function declarators, template argument lists) we
22068 won't be comparing a type to an expression, and we don't do any type
22069 adjustments. */
22071 {
22073 {
22076 {
22077 /* [temp.deduct.type] A template-argument can be
22078 deduced from a pointer to function or pointer
22079 to member function argument if the set of
22080 overloaded functions does not contain function
22081 templates and at most one of a set of
22082 overloaded functions provides a unique
22083 match. */
22087 /* If a unique match was not found, this is a
22088 non-deduced context, so we still succeed. */
22090 }
22096 }
22098 arg_strict |=
22100 }
22101 else
22106 /* For deduction from an init-list we need the actual list. */
22110 }
22112 /* for_each_template_parm callback that always returns 0. */
22114 static int
22116 {
22118 }
22120 /* for_each_template_parm any_fn callback to handle deduction of a template
22121 type argument from the type of an array bound. */
22123 static int
22125 {
22133 {
22139 }
22141 /* Keep walking. */
22143 }
22145 /* Try to deduce any not-yet-deduced template type arguments from the type of
22146 an array bound. This is handled separately from unify because 14.8.2.5 says
22147 "The type of a type parameter is only deduced from an array bound if it is
22148 not otherwise deduced." */
22150 static void
22152 {
22157 }
22159 /* Most parms like fn_type_unification.
22161 If SUBR is 1, we're being called recursively (to unify the
22162 arguments of a function or method parameter of a function
22163 template).
22165 CHECKS is a pointer to a vector of access checks encountered while
22166 substituting default template arguments. */
22168 static int
22170 tree full_targs,
22171 tree xparms,
22175 unification_kind_t strict,
22178 {
22183 tree parms;
22194 /* Reset the number of non-defaulted template arguments contained
22195 in TARGS. */
22198 again:
22206 {
22211 /* For a function parameter pack that occurs at the end of the
22212 parameter-declaration-list, the type A of each remaining
22213 argument of the call is compared with the type P of the
22214 declarator-id of the function parameter pack. */
22220 /* For a function parameter pack that does not occur at the
22221 end of the parameter-declaration-list, the type of the
22222 parameter pack is a non-deduced context. */
22229 explain_p))
22231 }
22236 {
22237 /* Unify the remaining arguments with the pack expansion type. */
22238 tree argvec;
22241 /* Allocate a TREE_VEC and copy in all of the arguments */
22246 /* Copy the parameter into parmvec. */
22252 /* Advance to the end of the list of parameters. */
22254 }
22256 /* Fail if we've reached the end of the parm list, and more args
22257 are present, and the parm list isn't variadic. */
22260 /* Fail if parms are left and they don't have default values and
22261 they aren't all deduced as empty packs (c++/57397). This is
22262 consistent with sufficient_parms_p. */
22265 {
22269 do
22270 {
22273 count++;
22275 }
22279 type_pack_p);
22280 }
22283 {
22284 tsubst_flags_t complain = (explain_p
22285 ? tf_warning_or_error
22290 {
22294 /* Clear the "incomplete" flags on all argument packs now so that
22295 substituting them into later default arguments works. */
22297 {
22300 }
22308 {
22313 }
22315 /* If this is an undeduced nontype parameter that depends on
22316 a type parameter, try another pass; its type may have been
22317 deduced from a later argument than the one from which
22318 this parameter can be deduced. */
22322 {
22325 }
22327 /* Core issue #226 (C++0x) [temp.deduct]:
22329 If a template argument has not been deduced, its
22330 default template argument, if any, is used.
22332 When we are in C++98 mode, TREE_PURPOSE will either
22333 be NULL_TREE or ERROR_MARK_NODE, so we do not need
22334 to explicitly check cxx_dialect here. */
22336 /* OK, there is a default argument. Wait until after the
22337 conversion check to do substitution. */
22340 /* If the type parameter is a parameter pack, then it will
22341 be deduced to an empty parameter pack. */
22343 {
22344 tree arg;
22347 {
22350 }
22351 else
22358 }
22361 }
22363 /* Now substitute into the default template arguments. */
22365 {
22381 {
22382 /* The type of this non-type parameter depends on undeduced
22383 parameters. Don't try to use its default argument yet,
22384 since we might deduce an argument for it on the next pass,
22385 but do check whether the arguments we already have cause
22386 substitution failure, so that that happens before we try
22387 later default arguments (78489). */
22390 NULL_TREE);
22394 else
22396 }
22397 else
22398 {
22399 /* Even if the call is happening in template context, getting
22400 here means it's non-dependent, and a default argument is
22401 considered a separate definition under [temp.decls], so we can
22402 do this substitution without processing_template_decl. This
22403 is important if the default argument contains something that
22404 might be instantiation-dependent like access (87480). */
22405 processing_template_decl_sentinel s;
22408 {
22409 /* First instatiate in template context, in case we still
22410 depend on undeduced template parameters. */
22413 NULL_TREE);
22417 /* We replaced all the tparms, substitute again out of
22418 template context. */
22420 }
22423 NULL_TREE);
22430 else
22432 }
22441 {
22443 /* The position of the first default template argument,
22444 is also the number of non-defaulted arguments in TARGS.
22445 Record that. */
22448 }
22449 }
22453 }
22459 }
22461 /* Subroutine of type_unification_real. Args are like the variables
22462 at the call site. ARG is an overloaded function (or template-id);
22463 we try deducing template args from each of the overloads, and if
22464 only one succeeds, we go with that. Modifies TARGS and returns
22465 true on success. */
22467 static bool
22469 tree targs,
22470 tree parm,
22471 tree arg,
22472 unification_kind_t strict,
22475 {
22482 {
22485 }
22486 else
22490 /* Handle `&x' where `x' is some static or non-static member
22491 function name. */
22497 /* Strip baselink information. */
22502 {
22503 /* If we got some explicit template args, we need to plug them into
22504 the affected templates before we try to unify, in case the
22505 explicit args will completely resolve the templates in question. */
22512 {
22525 {
22530 {
22531 /* Instantiate the function to deduce its return type. */
22535 }
22544 {
22547 }
22548 }
22551 }
22552 /* If no templates (or more than one) are fully resolved by the
22553 explicit arguments, this template-id is a non-deduced context; it
22554 could still be OK if we deduce all template arguments for the
22555 enclosing call through other arguments. */
22558 }
22560 /* If ARG is, for example, "(0, &f)" then its type will be unknown
22561 -- but the deduction does not succeed because the expression is
22562 not just the function on its own. */
22564 else
22566 {
22571 {
22574 }
22575 }
22577 /* [temp.deduct.type] A template-argument can be deduced from a pointer
22578 to function or pointer to member function argument if the set of
22579 overloaded functions does not contain function templates and at most
22580 one of a set of overloaded functions provides a unique match.
22582 So if we found multiple possibilities, we return success but don't
22583 deduce anything. */
22586 {
22590 {
22595 /* Don't forget explicit template arguments in a pack. */
22599 }
22600 }
22605 }
22607 /* Core DR 115: In contexts where deduction is done and fails, or in
22608 contexts where deduction is not done, if a template argument list is
22609 specified and it, along with any default template arguments, identifies
22610 a single function template specialization, then the template-id is an
22611 lvalue for the function template specialization. */
22613 tree
22615 {
22628 {
22631 }
22633 {
22636 }
22638 {
22641 }
22644 {
22648 /* If we got some explicit template args, we need to plug them into
22649 the affected templates before we try to unify, in case the
22650 explicit args will completely resolve the templates in question. */
22658 {
22671 {
22674 {
22677 }
22680 {
22683 }
22684 }
22685 }
22687 {
22695 {
22696 tree base
22699 }
22703 }
22705 /* There were no good options and at least one bad one, so let the
22706 user know what the problem is. */
22708 }
22710 }
22712 /* As above, but error out if the expression remains overloaded. */
22714 tree
22716 {
22719 {
22723 }
22725 }
22727 /* Subroutine of resolve_overloaded_unification; does deduction for a single
22728 overload. Fills TARGS with any deduced arguments, or error_mark_node if
22729 different overloads deduce different arguments for a given parm.
22730 ADDR_P is true if the expression for which deduction is being
22731 performed was of the form "& fn" rather than simply "fn".
22733 Returns 1 on success. */
22735 static int
22737 tree orig_targs,
22738 tree targs,
22739 tree parm,
22740 tree arg,
22741 unification_kind_t strict,
22745 {
22747 tree tempargs;
22753 /* [temp.deduct.type] A template-argument can be deduced from a pointer
22754 to function or pointer to member function argument if the set of
22755 overloaded functions does not contain function templates and at most
22756 one of a set of overloaded functions provides a unique match.
22758 So if this is a template, just return success. */
22770 /* We don't copy orig_targs for this because if we have already deduced
22771 some template args from previous args, unify would complain when we
22772 try to deduce a template parameter for the same argument, even though
22773 there isn't really a conflict. */
22780 /* First make sure we didn't deduce anything that conflicts with
22781 explicitly specified args. */
22783 {
22790 /* Since we're unifying against ourselves, we will fill in
22791 template args used in the function parm list with our own
22792 template parms. Discard them. */
22795 {
22796 /* Check that the argument at each index of the deduced argument pack
22797 is equivalent to the corresponding explicitly specified argument.
22798 We may have deduced more arguments than were explicitly specified,
22799 and that's OK. */
22801 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
22802 that's wrong if we deduce the same argument pack from multiple
22803 function arguments: it's only incomplete the first time. */
22816 }
22819 }
22822 {
22827 }
22830 }
22832 /* PARM is a template class (perhaps with unbound template
22833 parameters). ARG is a fully instantiated type. If ARG can be
22834 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
22835 TARGS are as for unify. */
22837 static tree
22840 {
22841 tree copy_of_targs;
22851 /* We need to make a new template argument vector for the call to
22852 unify. If we used TARGS, we'd clutter it up with the result of
22853 the attempted unification, even if this class didn't work out.
22854 We also don't want to commit ourselves to all the unifications
22855 we've already done, since unification is supposed to be done on
22856 an argument-by-argument basis. In other words, consider the
22857 following pathological case:
22859 template <int I, int J, int K>
22860 struct S {};
22862 template <int I, int J>
22863 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
22865 template <int I, int J, int K>
22866 void f(S<I, J, K>, S<I, I, I>);
22868 void g() {
22869 S<0, 0, 0> s0;
22870 S<0, 1, 2> s2;
22872 f(s0, s2);
22873 }
22875 Now, by the time we consider the unification involving `s2', we
22876 already know that we must have `f<0, 0, 0>'. But, even though
22877 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
22878 because there are two ways to unify base classes of S<0, 1, 2>
22879 with S<I, I, I>. If we kept the already deduced knowledge, we
22880 would reject the possibility I=1. */
22884 {
22888 }
22890 /* If unification failed, we're done. */
22896 }
22898 /* Given a template type PARM and a class type ARG, find the unique
22899 base type in ARG that is an instance of PARM. We do not examine
22900 ARG itself; only its base-classes. If there is not exactly one
22901 appropriate base class, return NULL_TREE. PARM may be the type of
22902 a partial specialization, as well as a plain template type. Used
22903 by unify. */
22905 static enum template_base_result
22908 {
22910 tree binfo;
22916 {
22917 /* The type could not be completed. */
22920 }
22922 /* Walk in inheritance graph order. The search order is not
22923 important, and this avoids multiple walks of virtual bases. */
22925 {
22930 {
22931 /* If there is more than one satisfactory baseclass, then:
22933 [temp.deduct.call]
22935 If they yield more than one possible deduced A, the type
22936 deduction fails.
22938 applies. */
22940 {
22941 /* [temp.deduct.call]/4.3: If there is a class C that is a
22942 (direct or indirect) base class of D and derived (directly or
22943 indirectly) from a class B and that would be a valid deduced
22944 A, the deduced A cannot be B or pointer to B, respectively. */
22946 /* Ignore r. */
22950 else
22951 {
22954 }
22955 }
22958 }
22959 }
22963 }
22965 /* Returns the level of DECL, which declares a template parameter. */
22967 static int
22969 {
22971 {
22981 }
22983 }
22985 /* Decide whether ARG can be unified with PARM, considering only the
22986 cv-qualifiers of each type, given STRICT as documented for unify.
22987 Returns nonzero iff the unification is OK on that basis. */
22989 static int
22991 {
22997 {
22998 /* Although a CVR qualifier is ignored when being applied to a
22999 substituted template parameter ([8.3.2]/1 for example), that
23000 does not allow us to unify "const T" with "int&" because both
23001 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
23002 It is ok when we're allowing additional CV qualifiers
23003 at the outer level [14.8.2.1]/3,1st bullet. */
23012 }
23023 }
23025 /* Determines the LEVEL and INDEX for the template parameter PARM. */
23026 void
23028 {
23032 {
23035 }
23036 else
23037 {
23040 }
23041 }
23043 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
23044 do { \
23045 if (unify (TP, TA, P, A, S, EP)) \
23046 return 1; \
23047 } while (0)
23049 /* Unifies the remaining arguments in PACKED_ARGS with the pack
23050 expansion at the end of PACKED_PARMS. Returns 0 if the type
23051 deduction succeeds, 1 otherwise. STRICT is the same as in
23052 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
23053 function call argument list. We'll need to adjust the arguments to make them
23054 types. SUBR tells us if this is from a recursive call to
23055 type_unification_real, or for comparing two template argument
23056 lists. */
23058 static int
23062 {
23063 tree parm
23069 /* Add in any args remembered from an earlier partial instantiation. */
23077 /* Determine the parameter packs we will be deducing from the
23078 pattern, and record their current deductions. */
23081 {
23085 /* Only template parameter packs can be deduced, not e.g. function
23086 parameter packs or __bases or __integer_pack. */
23090 /* Determine the index and level of this parameter pack. */
23095 /* Keep track of the parameter packs and their corresponding
23096 argument packs. */
23099 }
23101 /* Loop through all of the arguments that have not yet been
23102 unified and unify each with the pattern. */
23104 {
23105 tree parm;
23109 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
23110 or the element of its argument pack at the current index if
23111 this argument was explicitly specified. */
23113 {
23122 {
23125 }
23127 }
23129 /* If we had explicit template arguments, substitute them into the
23130 pattern before deduction. */
23132 {
23133 /* Some arguments might still be unspecified or dependent. */
23141 NULL_TREE);
23146 }
23147 else
23150 /* Unify the pattern with the current argument. */
23152 explain_p))
23155 /* For each parameter pack, collect the deduced value. */
23157 {
23163 }
23164 }
23166 /* Verify that the results of unification with the parameter packs
23167 produce results consistent with what we've seen before, and make
23168 the deduced argument packs available. */
23170 {
23177 /* By default keep the original deduced argument pack.
23178 If necessary, more specific code is going to update the
23179 resulting deduced argument later down in this function. */
23183 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
23184 actually deduce anything. */
23192 {
23193 /* If we had fewer function args than explicit template args,
23194 just use the explicits. */
23199 }
23202 {
23203 tree result;
23204 /* Build the deduced *_ARGUMENT_PACK. */
23206 {
23209 }
23210 else
23215 /* Note the deduced argument packs for this parameter
23216 pack. */
23218 }
23222 {
23223 /* We only had the explicitly-provided arguments before, but
23224 now we have a complete set of arguments. */
23230 }
23231 else
23232 {
23236 /* During template argument deduction for the aggregate deduction
23237 candidate, the number of elements in a trailing parameter pack
23238 is only deduced from the number of remaining function
23239 arguments if it is not otherwise deduced. */
23246 /* Inconsistent unification of this parameter pack. */
23248 bad_old_arg,
23249 bad_new_arg);
23250 }
23251 }
23254 }
23256 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
23257 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
23258 parameters and return value are as for unify. */
23260 static int
23264 {
23265 tree parm_max;
23266 tree arg_max;
23270 /* Our representation of array types uses "N - 1" as the
23271 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
23272 not an integer constant. We cannot unify arbitrarily
23273 complex expressions, so we eliminate the MINUS_EXPRs
23274 here. */
23278 {
23281 }
23285 {
23286 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
23287 trying to unify the type of a variable with the type
23288 of a template parameter. For example:
23290 template <unsigned int N>
23291 void f (char (&) [N]);
23292 int g();
23293 void h(int i) {
23294 char a[g(i)];
23295 f(a);
23296 }
23298 Here, the type of the ARG will be "int [g(i)]", and
23299 may be a SAVE_EXPR, etc. */
23303 }
23305 /* If only one of the bounds used a MINUS_EXPR, compensate
23306 by adding one to the other bound. */
23309 integer_type_node,
23310 parm_max,
23311 integer_one_node);
23314 integer_type_node,
23315 arg_max,
23316 integer_one_node);
23320 }
23322 /* Returns whether T, a P or A in unify, is a type, template or expression. */
23326 static pa_kind_t
23328 {
23337 else
23339 }
23341 /* Deduce the value of template parameters. TPARMS is the (innermost)
23342 set of template parameters to a template. TARGS is the bindings
23343 for those template parameters, as determined thus far; TARGS may
23344 include template arguments for outer levels of template parameters
23345 as well. PARM is a parameter to a template function, or a
23346 subcomponent of that parameter; ARG is the corresponding argument.
23347 This function attempts to match PARM with ARG in a manner
23348 consistent with the existing assignments in TARGS. If more values
23349 are deduced, then TARGS is updated.
23351 Returns 0 if the type deduction succeeds, 1 otherwise. The
23352 parameter STRICT is a bitwise or of the following flags:
23354 UNIFY_ALLOW_NONE:
23355 Require an exact match between PARM and ARG.
23356 UNIFY_ALLOW_MORE_CV_QUAL:
23357 Allow the deduced ARG to be more cv-qualified (by qualification
23358 conversion) than ARG.
23359 UNIFY_ALLOW_LESS_CV_QUAL:
23360 Allow the deduced ARG to be less cv-qualified than ARG.
23361 UNIFY_ALLOW_DERIVED:
23362 Allow the deduced ARG to be a template base class of ARG,
23363 or a pointer to a template base class of the type pointed to by
23364 ARG.
23365 UNIFY_ALLOW_INTEGER:
23366 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
23367 case for more information.
23368 UNIFY_ALLOW_OUTER_LEVEL:
23369 This is the outermost level of a deduction. Used to determine validity
23370 of qualification conversions. A valid qualification conversion must
23371 have const qualified pointers leading up to the inner type which
23372 requires additional CV quals, except at the outer level, where const
23373 is not required [conv.qual]. It would be normal to set this flag in
23374 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
23375 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
23376 This is the outermost level of a deduction, and PARM can be more CV
23377 qualified at this point.
23378 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
23379 This is the outermost level of a deduction, and PARM can be less CV
23380 qualified at this point. */
23382 static int
23385 {
23387 tree targ;
23388 tree tparm;
23390 tsubst_flags_t complain = (explain_p
23391 ? tf_warning_or_error
23394 /* I don't think this will do the right thing with respect to types.
23395 But the only case I've seen it in so far has been array bounds, where
23396 signedness is the only information lost, and I think that will be
23397 okay. VIEW_CONVERT_EXPR can appear with class NTTP, thanks to
23398 finish_id_expression_1, and are also OK. */
23406 /* We can't deduce anything from this, but we might get all the
23407 template args from other function args. */
23413 /* If PARM uses template parameters, then we can't bail out here,
23414 even if ARG == PARM, since we won't record unifications for the
23415 template parameters. We might need them if we're trying to
23416 figure out which of two things is more specialized. */
23420 /* Handle init lists early, so the rest of the function can assume
23421 we're dealing with a type. */
23423 {
23430 /* We can only deduce from an initializer list argument if the
23431 parameter is std::initializer_list or an array; otherwise this
23432 is a non-deduced context. */
23437 else
23438 {
23440 /* Deduction is defined in terms of a single type, so just punt
23441 on the (bizarre) std::initializer_list<T...>. */
23444 }
23449 /* If ELTTYPE has no deducible template parms, skip deduction from
23451 else
23453 {
23460 {
23464 /* It should only be possible to get here for a call. */
23466 elt_strict |= maybe_adjust_types_for_deduction
23469 }
23472 explain_p);
23473 }
23477 {
23478 /* Also deduce from the length of the initializer list. */
23485 }
23487 /* If the std::initializer_list<T> deduction worked, replace the
23488 deduced A with std::initializer_list<A>. */
23490 {
23495 }
23497 }
23499 /* If parm and arg aren't the same kind of thing (template, type, or
23500 expression), fail early. */
23504 /* Immediately reject some pairs that won't unify because of
23505 cv-qualification mismatches. */
23508 /* It is the elements of the array which hold the cv quals of an array
23509 type, and the elements might be template type parms. We'll check
23510 when we recurse. */
23512 /* We check the cv-qualifiers when unifying with template type
23513 parameters below. We want to allow ARG `const T' to unify with
23514 PARM `T' for example, when computing which of two templates
23515 is more specialized, for example. */
23529 {
23533 /* In a type which contains a nested-name-specifier, template
23534 argument values cannot be deduced for template parameters used
23535 within the nested-name-specifier. */
23547 /* The PARM is not one we're trying to unify. Just check
23548 to see if it matches ARG. */
23549 {
23554 else
23556 }
23563 /* Check for mixed types and values. */
23571 {
23574 {
23575 /* First try to match ARG directly. */
23577 explain_p);
23579 {
23580 /* Otherwise, look for a suitable base of ARG, as below. */
23587 }
23588 }
23589 /* ARG must be constructed from a template class or a template
23590 template parameter. */
23595 /* Deduce arguments T, i from TT<T> or TT<i>. */
23601 /* If the template is a template template parameter, use the
23602 TEMPLATE_TEMPLATE_PARM for matching. */
23605 /* Fall through to deduce template name. */
23606 }
23610 {
23611 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
23613 /* Simple cases: Value already set, does match or doesn't. */
23618 }
23619 else
23620 {
23621 /* If PARM is `const T' and ARG is only `int', we don't have
23622 a match unless we are allowing additional qualification.
23623 If ARG is `const int' and PARM is just `T' that's OK;
23624 that binds `const int' to `T'. */
23629 /* Consider the case where ARG is `const volatile int' and
23630 PARM is `const T'. Then, T should be `volatile int'. */
23631 arg = cp_build_qualified_type_real
23636 /* Simple cases: Value already set, does match or doesn't. */
23642 /* Make sure that ARG is not a variable-sized array. (Note
23643 that were talking about variable-sized arrays (like
23644 `int[n]'), rather than arrays of unknown size (like
23645 `int[]').) We'll get very confused by such a type since
23646 the bound of the array is not constant, and therefore
23647 not mangleable. Besides, such types are not allowed in
23648 ISO C++, so we can do as we please here. We do allow
23649 them for 'auto' deduction, since that isn't ABI-exposed. */
23653 /* Strip typedefs as in convert_template_argument. */
23655 }
23657 /* If ARG is a parameter pack or an expansion, we cannot unify
23658 against it unless PARM is also a parameter pack. */
23663 /* If the argument deduction results is a METHOD_TYPE,
23664 then there is a problem.
23665 METHOD_TYPE doesn't map to any real C++ type the result of
23666 the deduction cannot be of that type. */
23680 {
23681 /* The PARM is not one we're trying to unify. Just check
23682 to see if it matches ARG. */
23688 }
23694 {
23698 /* We're deducing from an array bound, the type doesn't matter. */
23704 }
23706 /* [temp.deduct.type] If, in the declaration of a function template
23707 with a non-type template-parameter, the non-type
23708 template-parameter is used in an expression in the function
23709 parameter-list and, if the corresponding template-argument is
23710 deduced, the template-argument type shall match the type of the
23711 template-parameter exactly, except that a template-argument
23712 deduced from an array bound may be of any integral type.
23713 The non-type parameter might use already deduced type parameters. */
23716 /* We don't have enough levels of args to do any substitution. This
23718 else
23719 {
23725 {
23730 }
23731 }
23734 /* Template-parameter dependent expression. Just accept it for now.
23735 It will later be processed in convert_template_argument. */
23736 ;
23740 /* OK. Ignore top-level quals here because a class-type template
23744 /* Convert the ARG to the type of PARM; the deduced non-type
23745 template argument must exactly match the types of the
23746 corresponding parameter. */
23749 {
23750 /* We haven't deduced the type of this parameter yet. */
23752 /* We deduce from array bounds in try_array_deduction. */
23755 {
23756 /* Deduce it from the non-type argument. */
23761 /* Now check whether the type of this parameter is still
23762 dependent, and give up if so. */
23768 }
23769 else
23770 /* Try again later. */
23772 }
23773 else
23776 /* If ARG is a parameter pack or an expansion, we cannot unify
23777 against it unless PARM is also a parameter pack. */
23782 {
23785 }
23790 {
23791 /* A pointer-to-member constant can be unified only with
23792 another constant. */
23796 /* Just unify the class member. It would be useless (and possibly
23797 wrong, depending on the strict flags) to unify also
23798 PTRMEM_CST_CLASS, because we want to be sure that both parm and
23799 arg refer to the same variable, even if through different
23800 classes. For instance:
23802 struct A { int x; };
23803 struct B : A { };
23805 Unification of &A::x and &B::x must succeed. */
23808 }
23811 {
23815 /* [temp.deduct.call]
23817 A can be another pointer or pointer to member type that can
23818 be converted to the deduced A via a qualification
23819 conversion (_conv.qual_).
23821 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
23822 This will allow for additional cv-qualification of the
23823 pointed-to types if appropriate. */
23826 /* The derived-to-base conversion only persists through one
23827 level of pointers. */
23832 }
23865 /* We have already checked cv-qualification at the top of the
23866 function. */
23870 /* As far as unification is concerned, this wins. Later checks
23871 will invalidate it if necessary. */
23874 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
23875 /* Type INTEGER_CST can come from ordinary constant template args. */
23887 {
23897 /* Check for pack expansions in the parameters. */
23899 {
23901 {
23903 /* We can unify against something with a trailing
23904 parameter pack. */
23906 else
23907 /* [temp.deduct.type]/9: If the template argument list of
23908 P contains a pack expansion that is not the last
23909 template argument, the entire template argument list
23910 is a non-deduced context. */
23912 }
23913 }
23915 /* If we don't have enough arguments to satisfy the parameters
23916 (not counting the pack expression at the end), or we have
23917 too many arguments for a parameter list that doesn't end in
23918 a pack expression, we can't unify. */
23924 /* Unify all of the parameters that precede the (optional)
23925 pack expression. */
23927 {
23932 }
23935 DEDUCE_EXACT,
23938 }
23946 {
23954 }
23959 {
23963 {
23964 /* First, we try to unify the PARM and ARG directly. */
23969 {
23970 /* Fallback to the special case allowed in
23971 [temp.deduct.call]:
23973 If P is a class, and P has the form
23974 template-id, then A can be a derived class of
23975 the deduced A. Likewise, if P is a pointer to
23976 a class of the form template-id, A can be a
23977 pointer to a derived class pointed to by the
23978 deduced A. */
23984 {
23985 /* Don't give the derived diagnostic if we're
23986 already dealing with the same template. */
23987 bool same_template
23993 }
23994 }
23995 }
23999 /* Perhaps PARM is something like S<U> and ARG is S<int>.
24000 Then, we should unify `int' and `U'. */
24002 else
24003 /* There's no chance of unification succeeding. */
24008 }
24015 {
24018 tree a;
24024 /* CV qualifications for methods can never be deduced, they must
24025 match exactly. We need to check them explicitly here,
24026 because type_unification_real treats them as any other
24027 cv-qualified parameter. */
24029 && (!check_cv_quals_for_unify
24057 {
24069 }
24072 }
24075 /* Unify a pointer to member with a pointer to member function, which
24076 deduces the type of the member as a function type. */
24078 {
24079 /* Check top-level cv qualifiers */
24087 /* Determine the type of the function we are unifying against. */
24091 }
24110 /* Matched cases are handled by the ARG == PARM test above. */
24114 /* We might get a variable as a non-type template argument in parm if the
24115 corresponding parameter is type-dependent. Make any necessary
24116 adjustments based on whether arg is a reference. */
24120 {
24125 }
24126 /* Now use the normal expression code to check whether they match. */
24137 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
24138 or UNDERLYING_TYPE nodes. */
24142 /* Unification fails if we hit an error node. */
24147 {
24157 }
24158 /* FALLTHRU */
24161 /* An unresolved overload is a nondeduced context. */
24167 expr:
24168 /* We must be looking at an expression. This can happen with
24169 something like:
24171 template <int I>
24172 void foo(S<I>, S<I + 2>);
24174 or
24176 template<typename T>
24177 void foo(A<T, T{}>);
24179 This is a "non-deduced context":
24181 [deduct.type]
24183 The non-deduced contexts are:
24185 --A non-type template argument or an array bound in which
24186 a subexpression references a template parameter.
24188 In these cases, we assume deduction succeeded, but don't
24189 actually infer any unifications. */
24194 else
24196 }
24197 }
24198 #undef RECUR_AND_CHECK_FAILURE
24199 \f
24200 /* Note that DECL can be defined in this translation unit, if
24201 required. */
24203 static void
24205 {
24206 tree clone;
24210 }
24212 /* Called if RESULT is explicitly instantiated, or is a member of an
24213 explicitly instantiated class. */
24215 void
24217 {
24220 /* If this entity has already been written out, it's too late to
24221 make any modifications. */
24225 /* consteval functions are never emitted. */
24230 /* For anonymous namespace we don't need to do anything. */
24232 {
24235 }
24238 /* The TREE_PUBLIC flag for function declarations will have been
24239 set correctly by tsubst. */
24242 /* This might have been set by an earlier implicit instantiation. */
24246 {
24249 }
24250 else
24251 {
24254 /* Always make artificials weak. */
24257 /* For WIN32 we also want to put explicit instantiations in
24258 linkonce sections. */
24263 /* If the function has already been instantiated, clear DECL_EXTERNAL,
24264 since start_preparsed_function wouldn't have if we had an earlier
24265 extern explicit instantiation. */
24267 }
24269 /* If EXTERN_P, then this function will not be emitted -- unless
24270 followed by an explicit instantiation, at which point its linkage
24271 will be adjusted. If !EXTERN_P, then this function will be
24272 emitted here. In neither circumstance do we want
24273 import_export_decl to adjust the linkage. */
24275 }
24277 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
24278 important template arguments. If any are missing, we check whether
24279 they're important by using error_mark_node for substituting into any
24280 args that were used for partial ordering (the ones between ARGS and END)
24281 and seeing if it bubbles up. */
24283 static bool
24285 {
24290 {
24293 }
24295 {
24299 }
24301 }
24303 /* Given two function templates PAT1 and PAT2, return:
24305 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
24306 -1 if PAT2 is more specialized than PAT1.
24307 0 if neither is more specialized.
24309 LEN indicates the number of parameters we should consider
24310 (defaulted parameters should not be considered).
24312 The 1998 std underspecified function template partial ordering, and
24313 DR214 addresses the issue. We take pairs of arguments, one from
24314 each of the templates, and deduce them against each other. One of
24315 the templates will be more specialized if all the *other*
24316 template's arguments deduce against its arguments and at least one
24317 of its arguments *does* *not* deduce against the other template's
24318 corresponding argument. Deduction is done as for class templates.
24319 The arguments used in deduction have reference and top level cv
24320 qualifiers removed. Iff both arguments were originally reference
24321 types *and* deduction succeeds in both directions, an lvalue reference
24322 wins against an rvalue reference and otherwise the template
24323 with the more cv-qualified argument wins for that pairing (if
24324 neither is more cv-qualified, they both are equal). Unlike regular
24325 deduction, after all the arguments have been deduced in this way,
24326 we do *not* verify the deduced template argument values can be
24327 substituted into non-deduced contexts.
24329 The logic can be a bit confusing here, because we look at deduce1 and
24330 targs1 to see if pat2 is at least as specialized, and vice versa; if we
24331 can find template arguments for pat1 to make arg1 look like arg2, that
24332 means that arg2 is at least as specialized as arg1. */
24334 int
24336 {
24349 /* Remove the this parameter from non-static member functions. If
24350 one is a non-static member function and the other is not a static
24351 member function, remove the first parameter from that function
24352 also. This situation occurs for operator functions where we
24353 locate both a member function (with this pointer) and non-member
24354 operator (with explicit first operand). */
24356 {
24361 }
24363 {
24366 {
24367 len--;
24369 }
24370 }
24372 /* If only one is a conversion operator, they are unordered. */
24376 /* Consider the return type for a conversion function */
24378 {
24381 len++;
24382 }
24384 processing_template_decl++;
24390 /* Stop when an ellipsis is seen. */
24392 {
24403 {
24404 /* When both arguments are pack expansions, we need only
24405 unify the patterns themselves. */
24409 /* This is the last comparison we need to do. */
24411 }
24414 {
24418 }
24421 {
24425 }
24431 {
24437 /* Setup the parameter vector, which contains only ARG1. */
24440 /* Setup the argument vector, which contains the remaining
24441 arguments. */
24450 /* We cannot deduce in the other direction, because ARG1 is
24451 a pack expansion but ARG2 is not. */
24453 }
24455 {
24461 /* Setup the parameter vector, which contains only ARG1. */
24464 /* Setup the argument vector, which contains the remaining
24465 arguments. */
24474 /* We cannot deduce in the other direction, because ARG2 is
24475 a pack expansion but ARG1 is not.*/
24477 }
24479 else
24480 {
24481 /* The normal case, where neither argument is a pack
24482 expansion. */
24489 }
24491 /* If we couldn't deduce arguments for tparms1 to make arg1 match
24492 arg2, then arg2 is not as specialized as arg1. */
24498 /* "If, for a given type, deduction succeeds in both directions
24499 (i.e., the types are identical after the transformations above)
24500 and both P and A were reference types (before being replaced with
24501 the type referred to above):
24502 - if the type from the argument template was an lvalue reference and
24503 the type from the parameter template was not, the argument type is
24504 considered to be more specialized than the other; otherwise,
24505 - if the type from the argument template is more cv-qualified
24506 than the type from the parameter template (as described above),
24507 the argument type is considered to be more specialized than the other;
24508 otherwise,
24509 - neither type is more specialized than the other." */
24512 {
24514 {
24517 else
24519 }
24521 {
24526 }
24527 }
24530 /* We've failed to deduce something in either direction.
24531 These must be unordered. */
24536 /* We have already processed all of the arguments in our
24537 handing of the pack expansion type. */
24542 }
24544 /* "In most cases, all template parameters must have values in order for
24545 deduction to succeed, but for partial ordering purposes a template
24546 parameter may remain without a value provided it is not used in the
24547 types being used for partial ordering."
24549 Thus, if we are missing any of the targs1 we need to substitute into
24550 origs1, then pat2 is not as specialized as pat1. This can happen when
24551 there is a nondeduced context. */
24557 processing_template_decl--;
24559 /* If both deductions succeed, the partial ordering selects the more
24560 constrained template. */
24561 /* P2113: If the corresponding template-parameters of the
24562 template-parameter-lists are not equivalent ([temp.over.link]) or if
24563 the function parameters that positionally correspond between the two
24564 templates are not of the same type, neither template is more
24565 specialized than the other. */
24570 {
24576 }
24578 /* All things being equal, if the next argument is a pack expansion
24579 for one function but not for the other, prefer the
24580 non-variadic function. FIXME this is bogus; see c++/41958. */
24584 {
24587 }
24593 else
24595 }
24597 /* Determine which of two partial specializations of TMPL is more
24598 specialized.
24600 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
24601 to the first partial specialization. The TREE_PURPOSE is the
24602 innermost set of template parameters for the partial
24603 specialization. PAT2 is similar, but for the second template.
24605 Return 1 if the first partial specialization is more specialized;
24606 -1 if the second is more specialized; 0 if neither is more
24607 specialized.
24609 See [temp.class.order] for information about determining which of
24610 two templates is more specialized. */
24612 static int
24614 {
24615 tree targs;
24624 /* Just like what happens for functions, if we are ordering between
24625 different template specializations, we may encounter dependent
24626 types in the arguments, and we need our dependency check functions
24627 to behave correctly. */
24631 {
24634 }
24638 {
24641 }
24644 /* If both deductions succeed, the partial ordering selects the more
24645 constrained template. */
24649 /* In the case of a tie where at least one of the templates
24650 has a parameter pack at the end, the template with the most
24651 non-packed parameters wins. */
24653 && any_deductions
24656 {
24662 /* We don't count the pack expansion at the end. */
24672 }
24675 }
24677 /* Return the template arguments that will produce the function signature
24678 DECL from the function template FN, with the explicit template
24679 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
24680 also match. Return NULL_TREE if no satisfactory arguments could be
24681 found. */
24683 static tree
24685 {
24689 tree decl_arg_types;
24692 tree arg;
24696 /* Never do unification on the 'this' parameter. */
24718 }
24720 /* Return the innermost template arguments that, when applied to a partial
24721 specialization SPEC_TMPL of TMPL, yield the ARGS.
24723 For example, suppose we have:
24725 template <class T, class U> struct S {};
24726 template <class T> struct S<T*, int> {};
24728 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
24729 partial specialization and the ARGS will be {double*, int}. The resulting
24730 vector will be {double}, indicating that `T' is bound to `double'. */
24732 static tree
24734 {
24736 tree spec_args
24739 tree deduced_args;
24740 tree innermost_deduced_args;
24744 {
24748 innermost_deduced_args);
24749 }
24750 else
24754 again:
24763 {
24765 {
24771 }
24773 }
24776 {
24779 }
24781 /* Verify that nondeduced template arguments agree with the type
24782 obtained from argument deduction.
24784 For example:
24786 struct A { typedef int X; };
24787 template <class T, class U> struct C {};
24788 template <class T> struct C<T, typename T::X> {};
24790 Then with the instantiation `C<A, int>', we can deduce that
24791 `T' is `A' but unify () does not check whether `typename T::X'
24792 is `int'. */
24803 /* We only need to check the innermost arguments; the other
24804 arguments will always agree. */
24809 /* Now that we have bindings for all of the template arguments,
24810 ensure that the arguments deduced for the template template
24811 parameters have compatible template parameter lists. See the use
24812 of template_template_parm_bindings_ok_p in fn_type_unification
24813 for more information. */
24818 }
24820 // Compare two function templates T1 and T2 by deducing bindings
24821 // from one against the other. If both deductions succeed, compare
24822 // constraints to see which is more constrained.
24823 static int
24825 {
24830 {
24833 }
24836 {
24839 }
24841 // If both deductions succeed, then one may be more constrained.
24846 }
24848 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
24849 Return the TREE_LIST node with the most specialized template, if
24850 any. If there is no most specialized template, the error_mark_node
24851 is returned.
24853 Note that this function does not look at, or modify, the
24854 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
24855 returned is one of the elements of INSTANTIATIONS, callers may
24856 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
24857 and retrieve it from the value returned. */
24859 tree
24861 {
24868 {
24874 {
24875 /* Equally specialized, move to next function. If there
24876 is no next function, nothing's most specialized. */
24881 }
24882 }
24885 /* Now verify that champ is better than everything earlier in the
24886 instantiation list. */
24889 {
24892 }
24893 }
24895 processing_template_decl--;
24901 }
24903 /* If DECL is a specialization of some template, return the most
24904 general such template. Otherwise, returns NULL_TREE.
24906 For example, given:
24908 template <class T> struct S { template <class U> void f(U); };
24910 if TMPL is `template <class U> void S<int>::f(U)' this will return
24911 the full template. This function will not trace past partial
24912 specializations, however. For example, given in addition:
24914 template <class T> struct S<T*> { template <class U> void f(U); };
24916 if TMPL is `template <class U> void S<int*>::f(U)' this will return
24917 `template <class T> template <class U> S<T*>::f(U)'. */
24919 tree
24921 {
24923 {
24926 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
24927 template friend, or a FIELD_DECL for a capture pack. */
24930 }
24932 /* Look for more and more general templates. */
24934 {
24935 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
24936 (See cp-tree.h for details.) */
24945 /* Stop if we run into an explicitly specialized class template. */
24952 }
24955 }
24957 /* Return the most specialized of the template partial specializations
24958 which can produce TARGET, a specialization of some class or variable
24959 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
24960 a TEMPLATE_DECL node corresponding to the partial specialization, while
24961 the TREE_PURPOSE is the set of template arguments that must be
24962 substituted into the template pattern in order to generate TARGET.
24964 If the choice of partial specialization is ambiguous, a diagnostic
24965 is issued, and the error_mark_node is returned. If there are no
24966 partial specializations matching TARGET, then NULL_TREE is
24967 returned, indicating that the primary template should be used. */
24969 tree
24971 {
24973 tree t;
24974 tree champ;
24981 {
24985 }
24987 {
24990 }
24992 {
24996 }
24997 else
25002 /* For determining which partial specialization to use, only the
25003 innermost args are interesting. */
25005 {
25008 }
25010 /* The caller hasn't called push_to_top_level yet, but we need
25011 get_partial_spec_bindings to be done in non-template context so that we'll
25012 fully resolve everything. */
25013 processing_template_decl_sentinel ptds;
25016 {
25019 tree spec_tmpl;
25021 {
25022 /* Substitute in the template args from the enclosing class. */
25028 }
25029 else
25034 {
25038 /* Keep the candidate only if the constraints are satisfied,
25039 or if we're not compiling with concepts. */
25042 {
25045 }
25046 }
25047 }
25057 {
25060 ;
25061 else
25062 {
25064 {
25067 {
25070 }
25071 }
25073 }
25074 }
25078 {
25081 {
25084 }
25085 }
25088 {
25095 else
25099 {
25104 }
25107 }
25110 }
25112 /* Explicitly instantiate DECL. */
25114 void
25116 {
25121 /* An error occurred, for which grokdeclarator has already issued
25122 an appropriate message. */
25125 {
25128 }
25130 {
25133 else
25136 }
25142 {
25143 /* There is an asymmetry here in the way VAR_DECLs and
25144 FUNCTION_DECLs are handled by grokdeclarator. In the case of
25145 the latter, the DECL we get back will be marked as a
25146 template instantiation, and the appropriate
25147 DECL_TEMPLATE_INFO will be set up. This does not happen for
25148 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
25149 should handle VAR_DECLs as it currently handles
25150 FUNCTION_DECLs. */
25152 {
25155 }
25158 {
25161 }
25163 {
25168 }
25169 }
25171 {
25174 }
25175 else
25178 /* Check for various error cases. Note that if the explicit
25179 instantiation is valid the RESULT will currently be marked as an
25180 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
25181 until we get here. */
25184 {
25185 /* DR 259 [temp.spec].
25187 Both an explicit instantiation and a declaration of an explicit
25188 specialization shall not appear in a program unless the explicit
25189 instantiation follows a declaration of the explicit specialization.
25191 For a given set of template parameters, if an explicit
25192 instantiation of a template appears after a declaration of an
25193 explicit specialization for that template, the explicit
25194 instantiation has no effect. */
25196 }
25198 {
25199 /* [temp.spec]
25201 No program shall explicitly instantiate any template more
25202 than once.
25204 We check DECL_NOT_REALLY_EXTERN so as not to complain when
25205 the first instantiation was `extern' and the second is not,
25206 and EXTERN_P for the opposite case. */
25209 /* If an "extern" explicit instantiation follows an ordinary
25210 explicit instantiation, the template is instantiated. */
25213 }
25215 {
25218 }
25220 {
25223 }
25226 ;
25228 {
25231 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
25234 }
25235 else
25243 }
25245 static void
25247 {
25253 {
25256 }
25257 }
25259 /* Perform an explicit instantiation of template class T. STORAGE, if
25260 non-null, is the RID for extern, inline or static. COMPLAIN is
25261 nonzero if this is called from the parser, zero if called recursively,
25262 since the standard is unclear (as detailed below). */
25264 void
25266 {
25268 {
25272 else
25275 }
25280 {
25283 t);
25285 }
25287 /* At most one of these will be true. */
25293 {
25295 {
25298 "ISO C++ 1998 forbids the use of %<extern%> on "
25300 }
25301 else
25303 "ISO C++ forbids the use of %qE"
25312 else
25314 storage);
25315 }
25318 /* DR 259 [temp.spec].
25320 Both an explicit instantiation and a declaration of an explicit
25321 specialization shall not appear in a program unless the
25322 explicit instantiation follows a declaration of the explicit
25323 specialization.
25325 For a given set of template parameters, if an explicit
25326 instantiation of a template appears after a declaration of an
25327 explicit specialization for that template, the explicit
25328 instantiation has no effect. */
25332 {
25333 /* We've already instantiated the template. */
25335 /* [temp.spec]
25337 No program shall explicitly instantiate any template more
25338 than once.
25340 If EXTERN_P then this is ok. */
25346 }
25354 /* In contrast to implicit instantiation, where only the
25355 declarations, and not the definitions, of members are
25356 instantiated, we have here:
25358 [temp.explicit]
25360 An explicit instantiation that names a class template
25361 specialization is also an explicit instantiation of the same
25362 kind (declaration or definition) of each of its members (not
25363 including members inherited from base classes and members
25364 that are templates) that has not been previously explicitly
25365 specialized in the translation unit containing the explicit
25366 instantiation, provided that the associated constraints, if
25367 any, of that member are satisfied by the template arguments
25368 of the explicit instantiation. */
25372 && !static_p
25376 {
25381 }
25383 {
25389 }
25390 }
25392 /* Given a function DECL, which is a specialization of TMPL, modify
25393 DECL to be a re-instantiation of TMPL with the same template
25394 arguments. TMPL should be the template into which tsubst'ing
25395 should occur for DECL, not the most general template.
25397 One reason for doing this is a scenario like this:
25399 template <class T>
25400 void f(const T&, int i);
25402 void g() { f(3, 7); }
25404 template <class T>
25405 void f(const T& t, const int i) { }
25407 Note that when the template is first instantiated, with
25408 instantiate_template, the resulting DECL will have no name for the
25409 first parameter, and the wrong type for the second. So, when we go
25410 to instantiate the DECL, we regenerate it. */
25412 static void
25414 {
25415 /* The arguments used to instantiate DECL, from the most general
25416 template. */
25417 tree code_pattern;
25421 /* Make sure that we can see identifiers, and compute access
25422 correctly. */
25426 {
25427 tree specs;
25431 /* Use the source location of the definition. */
25439 /* Instantiate a dynamic exception-specification. noexcept will be
25440 handled below. */
25443 {
25449 specs);
25450 }
25452 /* Merge parameter declarations. */
25456 {
25463 }
25465 /* Merge additional specifiers from the CODE_PATTERN. */
25471 }
25473 {
25482 }
25483 else
25487 }
25489 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
25490 substituted to get DECL. */
25492 tree
25494 {
25497 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
25498 for the instantiation. This is not always the most general
25499 template. Consider, for example:
25501 template <class T>
25502 struct S { template <class U> void f();
25503 template <> void f<int>(); };
25505 and an instantiation of S<double>::f<int>. We want TD to be the
25506 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
25508 more general template. */
25510 /* We must also deal with friend templates. Given:
25512 template <class T> struct S {
25513 template <class U> friend void f() {};
25514 };
25516 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
25517 so far as the language is concerned, but that's still
25518 where we get the pattern for the instantiation from. On
25519 other hand, if the definition comes outside the class, say:
25521 template <class T> struct S {
25522 template <class U> friend void f();
25523 };
25524 template <class U> friend void f() {}
25526 we don't need to look any further. That's what the check for
25527 DECL_INITIAL is for. */
25531 {
25532 /* The present template, TD, should not be a definition. If it
25533 were a definition, we should be using it! Note that we
25534 cannot restructure the loop to just keep going until we find
25535 a template with a definition, since that might go too far if
25536 a specialization was declared, but not defined. */
25538 /* Fetch the more general template. */
25540 }
25543 }
25545 /* Returns true if we need to instantiate this template instance even if we
25546 know we aren't going to emit it. */
25548 bool
25550 {
25551 /* We always instantiate inline functions so that we can inline them. An
25552 explicit instantiation declaration prohibits implicit instantiation of
25553 non-inline functions. With high levels of optimization, we would
25554 normally inline non-inline functions -- but we're not allowed to do
25555 that for "extern template" functions. Therefore, we check
25556 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
25560 /* And we need to instantiate static data members so that
25561 their initializers are available in integral constant
25562 expressions. */
25565 }
25567 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
25568 instantiate it now, modifying TREE_TYPE (fn). Returns false on
25569 error, true otherwise. */
25571 bool
25573 {
25577 /* Don't instantiate a noexcept-specification from template context. */
25583 {
25585 /* We're in start_preparsed_function, keep going. */
25592 }
25606 /* For a member friend template we can get a TEMPLATE_DECL. Let's use
25607 its FUNCTION_DECL for the rest of this function -- push_access_scope
25608 doesn't accept TEMPLATE_DECLs. */
25610 {
25613 }
25616 {
25621 }
25623 {
25627 {
25630 /* This might have failed because of an unparsed DMI, so
25631 let's try again later. */
25633 }
25635 {
25636 /* If hash_set::add returns true, the element was already there. */
25641 fn);
25643 }
25645 {
25652 {
25653 /* If needed, set current_class_ptr for the benefit of
25654 tsubst_copy/PARM_DECL. The exception pattern will
25655 refer to the parm of the template, not the
25656 instantiation. */
25659 {
25664 }
25665 }
25667 /* If this function is represented by a TEMPLATE_DECL, then
25668 the deferred noexcept-specification might still contain
25669 dependent types, even after substitution. And we need the
25670 dependency check functions to work in build_noexcept_spec. */
25674 /* Do deferred instantiation of the noexcept-specifier. */
25681 /* Build up the noexcept-specification. */
25691 }
25692 else
25697 }
25700 {
25701 /* This failed with a hard error, so let's go with false. */
25704 }
25711 }
25713 /* We're starting to process the function INST, an instantiation of PATTERN;
25714 add their parameters to local_specializations. */
25716 static void
25718 {
25722 {
25726 }
25728 {
25730 {
25733 }
25734 else
25735 {
25736 /* Register the (value) argument pack as a specialization of
25737 TMPL_PARM, then move on. */
25740 }
25741 }
25743 }
25745 /* Instantiate the body of D using PATTERN with ARGS. We have
25746 already determined PATTERN is the correct template to use.
25747 NESTED_P is true if this is a nested function, in which case
25748 PATTERN will be a FUNCTION_DECL not a TEMPLATE_DECL. */
25750 static void
25752 {
25757 {
25760 }
25761 else
25762 /* Only OMP reductions are nested. */
25769 bool push_to_top
25770 = !(current_function_decl
25776 else
25777 {
25782 }
25785 {
25786 /* The variable might be a lambda's extra scope, and that
25787 lambda's visibility depends on D's. */
25790 }
25792 /* Mark D as instantiated so that recursive calls to
25793 instantiate_decl do not try to instantiate it again. */
25797 /* Regenerate the declaration in case the template has been modified
25798 by a subsequent redeclaration. */
25801 /* We already set the file and line above. Reset them now in case
25802 they changed as a result of calling regenerate_decl_from_template. */
25806 {
25807 /* Clear out DECL_RTL; whatever was there before may not be right
25808 since we've reset the type of the declaration. */
25812 /* The initializer is placed in DECL_INITIAL by
25813 regenerate_decl_from_template so we don't need to
25814 push/pop_access_scope again here. Pull it out so that
25815 cp_finish_decl can process it. */
25821 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
25822 initializer. That function will defer actual emission until
25823 we have a chance to determine linkage. */
25826 /* Enter the scope of D so that access-checking works correctly. */
25836 }
25840 {
25841 /* Set up the list of local specializations. */
25845 /* Set up context. */
25848 else
25849 {
25853 }
25855 /* Create substitution entries for the parameters. */
25858 /* Substitute into the body of the function. */
25862 else
25863 {
25868 /* Set the current input_location to the end of the function
25869 so that finish_function knows where we are. */
25870 input_location
25873 /* Remember if we saw an infinite loop in the template. */
25874 current_function_infinite_loop
25876 }
25878 /* Finish the function. */
25881 else
25882 {
25885 }
25889 }
25891 /* We're not deferring instantiation any more. */
25897 else
25902 }
25904 /* Produce the definition of D, a _DECL generated from a template. If
25905 DEFER_OK is true, then we don't have to actually do the
25906 instantiation now; we just have to do it sometime. Normally it is
25907 an error if this is an explicit instantiation but D is undefined.
25908 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
25909 instantiated class template. */
25911 tree
25913 {
25915 tree gen_args;
25916 tree args;
25917 tree td;
25918 tree code_pattern;
25919 tree spec;
25920 tree gen_tmpl;
25928 /* This function should only be used to instantiate templates for
25929 functions and static member variables. */
25932 /* A concept is never instantiated. */
25938 /* We may have a pending instantiation of D itself. */
25941 /* Variables are never deferred; if instantiation is required, they
25942 are instantiated right away. That allows for better code in the
25943 case that an expression refers to the value of the variable --
25944 if the variable has a constant value the referring expression can
25945 take advantage of that fact. */
25949 /* Don't instantiate cloned functions. Instead, instantiate the
25950 functions they cloned. */
25959 /* D has already been instantiated or explicitly specialized, so
25960 there's nothing for us to do here.
25962 It might seem reasonable to check whether or not D is an explicit
25963 instantiation, and, if so, stop here. But when an explicit
25964 instantiation is deferred until the end of the compilation,
25965 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
25966 the instantiation. */
25969 /* Check to see whether we know that this template will be
25970 instantiated in some other file, as with "extern template"
25971 extension. */
25974 /* In general, we do not instantiate such templates. */
25981 /* We should already have the extra args. */
25985 /* And what's in the hash table should match D. */
25987 == d
25990 /* This needs to happen before any tsubsting. */
25996 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
25997 for the instantiation. */
26002 {
26003 /* Look up an explicit specialization, if any. */
26007 {
26010 }
26011 }
26015 /* We should never be trying to instantiate a member of a class
26016 template or partial specialization. */
26021 /* In the case of a friend template whose definition is provided
26022 outside the class, we may have too many arguments. Drop the
26023 ones we don't need. The same is true for specializations. */
26024 args = get_innermost_template_args
26028 {
26034 }
26035 else
26036 {
26040 else
26042 }
26044 /* We may be in the middle of deferred access check. Disable it now. */
26047 /* Unless an explicit instantiation directive has already determined
26048 the linkage of D, remember that a definition is available for
26049 this entity. */
26059 /* If D is a member of an explicitly instantiated class template,
26060 and no definition is available, treat it like an implicit
26061 instantiation. */
26064 {
26065 /* Leave linkage flags alone on instantiations with anonymous
26066 visibility. */
26068 {
26071 }
26073 }
26075 /* Defer all other templates, unless we have been explicitly
26076 forbidden from doing so. */
26078 template. */
26079 ! pattern_defined
26080 /* If it's OK to postpone instantiation, do so. */
26081 || defer_ok
26082 /* If this is a static data member that will be defined
26083 elsewhere, we don't want to instantiate the entire data
26084 member, but we do want to instantiate the initializer so that
26085 we can substitute that elsewhere. */
26087 /* Handle here a deleted function too, avoid generating
26088 its body (c++/61080). */
26090 {
26091 /* The definition of the static data member is now required so
26092 we must substitute the initializer. */
26096 {
26097 tree ns;
26098 tree init;
26107 args,
26110 /* If instantiating the initializer involved instantiating this
26111 again, don't call cp_finish_decl twice. */
26113 {
26114 /* Make sure the initializer is still constant, in case of
26115 circular dependency (template/instantiate6.C). */
26116 const_init
26120 LOOKUP_ONLYCONVERTING);
26121 }
26125 }
26127 /* We restore the source position here because it's used by
26128 add_pending_template. */
26134 /* [temp.explicit]
26136 The definition of a non-exported function template, a
26137 non-exported member function template, or a non-exported
26138 member function or static data member of a class template
26139 shall be present in every translation unit in which it is
26140 explicitly instantiated. */
26144 /* If we're in unevaluated context, we just wanted to get the
26145 constant value; this isn't an odr use, so don't queue
26146 a full instantiation. */
26148 /* ??? Historically, we have instantiated inline functions, even
26149 when marked as "extern template". */
26152 }
26153 else
26154 {
26159 }
26169 }
26171 /* Run through the list of templates that we wish we could
26172 instantiate, and instantiate any we can. RETRIES is the
26173 number of times we retry pending template instantiation. */
26175 void
26177 {
26181 /* Instantiating templates may trigger vtable generation. This in turn
26182 may require further template instantiations. We place a limit here
26183 to avoid infinite loop. */
26185 {
26189 "template instantiation depth exceeds maximum of %d"
26190 " instantiating %q+D, possibly from virtual table generation"
26194 /* Pretend that we defined it. */
26197 }
26199 do
26200 {
26205 {
26210 {
26212 {
26227 }
26230 }
26231 else
26232 {
26235 {
26236 instantiation
26242 }
26246 }
26249 {
26250 /* If INSTANTIATION has been instantiated, then we don't
26251 need to consider it again in the future. */
26256 }
26257 else
26258 {
26261 }
26264 }
26266 }
26270 }
26272 /* Substitute ARGVEC into T, which is a list of initializers for
26273 either base class or a non-static data member. The TREE_PURPOSEs
26274 are DECLs, and the TREE_VALUEs are the initializer values. Used by
26275 instantiate_decl. */
26277 static tree
26279 {
26284 {
26285 tree decl;
26286 tree init;
26292 {
26293 tree expr;
26294 tree arg;
26296 /* Expand the base class expansion type into separate base
26297 classes. */
26299 tf_warning_or_error,
26300 NULL_TREE);
26304 /* We'll be building separate TREE_LISTs of arguments for
26305 each base. */
26311 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
26312 expand each argument in the TREE_VALUE of t. */
26319 /* VOID_TYPE_NODE is used to indicate
26320 value-initialization. */
26321 {
26324 }
26325 else
26326 {
26327 /* Substitute parameter packs into each argument in the
26328 TREE_LIST. */
26331 {
26332 tree expanded_exprs;
26334 /* Expand the argument. */
26335 tree value;
26338 else
26339 {
26342 }
26343 expanded_exprs
26345 tf_warning_or_error,
26346 NULL_TREE);
26350 /* Prepend each of the expanded expressions to the
26351 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
26359 else
26364 }
26367 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
26368 since we built them backwards. */
26370 {
26373 }
26374 }
26375 }
26378 {
26380 {
26384 }
26385 else
26386 {
26387 tree tmp;
26402 /* If we had an initializer but it instantiated to nothing,
26403 value-initialize the object. This will only occur when
26404 the initializer was a pack expansion where the parameter
26405 packs used in that expansion were of length zero. */
26408 }
26412 {
26414 decl);
26416 }
26417 /* Look for a target constructor. */
26421 {
26424 {
26428 }
26430 }
26433 {
26435 /* Carry over the dummy TREE_TYPE node containing the source
26436 location. */
26440 }
26441 }
26442 }
26444 }
26446 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
26447 is the instantiation (which should have been created with
26448 start_enum) and ARGS are the template arguments to use. */
26450 static void
26452 {
26453 tree e;
26459 {
26460 tree value;
26461 tree decl;
26464 /* Note that in a template enum, the TREE_VALUE is the
26465 CONST_DECL, not the corresponding INTEGER_CST. */
26470 /* Give this enumeration constant the correct access. */
26473 /* Actually build the enumerator itself. Here we're assuming that
26474 enumerators can't have dependent attributes. */
26477 }
26487 }
26489 /* DECL is a FUNCTION_DECL that is a template specialization. Return
26490 its type -- but without substituting the innermost set of template
26491 arguments. So, innermost set of template parameters will appear in
26492 the type. */
26494 tree
26496 {
26497 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
26499 }
26501 /* Return truthvalue if we're processing a template different from
26502 the last one involved in diagnostics. */
26503 bool
26505 {
26507 }
26509 /* Remember current template involved in diagnostics. */
26510 void
26512 {
26514 }
26518 {
26520 }
26522 /* Return TRUE if current_function_decl is being instantiated, false
26523 otherwise. */
26525 bool
26527 {
26531 }
26533 /* [temp.param] Check that template non-type parm TYPE is of an allowable
26534 type. Return false for ok, true for disallowed. Issue error and
26535 inform messages under control of COMPLAIN. */
26537 static bool
26539 {
26550 {
26552 {
26557 }
26559 }
26566 /* A bound template template parm could later be instantiated to have a valid
26567 nontype parm type via an alias template. */
26576 {
26584 {
26585 auto_diagnostic_group d;
26589 }
26591 }
26593 {
26598 }
26601 {
26604 else
26606 type);
26607 }
26609 }
26611 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
26612 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
26614 static bool
26616 {
26617 tree scope;
26619 /* [temp.dep.type]
26621 A type is dependent if it is:
26623 -- a template parameter. Template template parameters are types
26624 for us (since TYPE_P holds true for them) so we handle
26625 them here. */
26629 /* -- a qualified-id with a nested-name-specifier which contains a
26630 class-name that names a dependent type or whose unqualified-id
26631 names a dependent type. */
26635 /* An alias template specialization can be dependent even if the
26636 resulting type is not. */
26640 /* -- a cv-qualified type where the cv-unqualified type is
26641 dependent.
26642 No code is necessary for this bullet; the code below handles
26643 cv-qualified types, and we don't want to strip aliases with
26644 TYPE_MAIN_VARIANT because of DR 1558. */
26645 /* -- a compound type constructed from any dependent type. */
26653 {
26654 tree arg_type;
26659 arg_type;
26664 /* A value-dependent noexcept-specifier makes the type dependent. */
26667 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
26668 affect overload resolution and treating it as dependent breaks
26669 things. Same for an unparsed noexcept expression. */
26675 }
26676 /* -- an array type constructed from any dependent type or whose
26677 size is specified by a constant expression that is
26678 value-dependent.
26680 We checked for type- and value-dependence of the bounds in
26681 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
26683 {
26688 }
26690 /* -- a template-id in which either the template name is a template
26691 parameter ... */
26694 /* ... or any of the template arguments is a dependent type or
26695 an expression that is type-dependent or value-dependent. */
26697 && (any_dependent_template_arguments_p
26701 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
26702 dependent; if the argument of the `typeof' expression is not
26703 type-dependent, then it should already been have resolved. */
26709 /* A template argument pack is dependent if any of its packed
26710 arguments are. */
26712 {
26718 }
26720 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
26721 be template parameters. */
26728 /* The standard does not specifically mention types that are local
26729 to template functions or local classes, but they should be
26730 considered dependent too. For example:
26732 template <int I> void f() {
26733 enum E { a = I };
26734 S<sizeof (E)> s;
26735 }
26737 The size of `E' cannot be known until the value of `I' has been
26738 determined. Therefore, `E' must be considered dependent. */
26742 /* Don't use type_dependent_expression_p here, as it can lead
26743 to infinite recursion trying to determine whether a lambda
26744 nested in a lambda is dependent (c++/47687). */
26748 && (any_dependent_template_arguments_p
26752 /* Other types are non-dependent. */
26754 }
26756 /* Returns TRUE if TYPE is dependent, in the sense of
26757 [temp.dep.type]. Note that a NULL type is considered dependent. */
26759 bool
26761 {
26762 /* If there are no template parameters in scope, then there can't be
26763 any dependent types. */
26765 {
26766 /* If we are not processing a template, then nobody should be
26767 providing us with a dependent type. */
26771 }
26773 /* If the type is NULL, we have not computed a type for the entity
26774 in question; in that case, the type is dependent. */
26778 /* Erroneous types can be considered non-dependent. */
26782 /* If we have not already computed the appropriate value for TYPE,
26783 do so now. */
26785 {
26788 }
26791 }
26793 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
26794 lookup. In other words, a dependent type that is not the current
26795 instantiation. */
26797 bool
26799 {
26802 }
26804 /* T is a SCOPE_REF. Return whether it represents a non-static member of
26805 an unknown base of 'this' (and is therefore instantiation-dependent). */
26807 static bool
26809 {
26826 }
26828 /* T is a SCOPE_REF; return whether we need to consider it
26829 instantiation-dependent so that we can check access at instantiation
26830 time even though we know which member it resolves to. */
26832 static bool
26834 {
26841 else
26843 }
26845 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
26846 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
26847 expression. */
26849 /* Note that this predicate is not appropriate for general expressions;
26850 only constant expressions (that satisfy potential_constant_expression)
26851 can be tested for value dependence. */
26853 bool
26855 {
26859 /* A type-dependent expression is also value-dependent. */
26864 {
26866 /* A dependent member function of the current instantiation. */
26870 /* A dependent member function of the current instantiation. */
26877 /* A name that has not been looked up -- must be dependent. */
26881 /* A non-type template parm. */
26885 /* A non-type template parm. */
26891 /* A constant with literal type and is initialized
26892 with an expression that is value-dependent. */
26894 /* FIXME cp_finish_decl doesn't fold reference initializers. */
26898 {
26901 /* __PRETTY_FUNCTION__ inside a template function is dependent
26902 on the name of the function. */
26904 /* It might be used in a template, but not a template
26905 function, in which case its DECL_VALUE_EXPR will be
26906 "top level". */
26909 }
26918 /* These expressions are value-dependent if the type to which
26919 the cast occurs is dependent or the expression being casted
26920 is value-dependent. */
26921 {
26927 /* A functional cast has a list of operands. */
26930 {
26931 /* If there are no operands, it must be an expression such
26932 as "int()". This should not happen for aggregate types
26933 because it would form non-constant expressions. */
26938 }
26944 }
26949 /* FALLTHRU */
26952 /* A `sizeof' expression is value-dependent if the operand is
26953 type-dependent or is a pack expansion. */
26962 /* An 'encode' expression is value-dependent if the operand is
26963 type-dependent. */
26972 /* All instantiation-dependent expressions should also be considered
26973 value-dependent. */
26981 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
26982 is value-dependent. */
26983 {
26992 }
26995 {
27012 }
27023 {
27027 }
27030 /* Treat all requires-expressions as value-dependent so
27031 we don't try to fold them. */
27038 {
27045 {
27047 /* In a call to a constexpr member function, look through the
27048 implicit ADDR_EXPR on the object argument so that it doesn't
27049 cause the call to be considered value-dependent. We also
27050 look through it in potential_constant_expression. */
27057 }
27059 }
27065 {
27067 tree val;
27074 }
27077 /* Treat a GNU statement expression as dependent to avoid crashing
27078 under instantiate_non_dependent_expr; it can't be constant. */
27082 /* A constant expression is value-dependent if any subexpression is
27083 value-dependent. */
27085 {
27092 {
27096 {
27099 /* In some cases, some of the operands may be missing.
27100 (For example, in the case of PREDECREMENT_EXPR, the
27101 amount to increment by may be missing.) That doesn't
27102 make the expression dependent. */
27105 }
27106 }
27110 }
27112 }
27114 /* The expression is not value-dependent. */
27116 }
27118 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
27119 [temp.dep.expr]. Note that an expression with no type is
27120 considered dependent. Other parts of the compiler arrange for an
27121 expression with type-dependent subexpressions to have no type, so
27122 this function doesn't have to be fully recursive. */
27124 bool
27126 {
27135 /* An unresolved name is always dependent. */
27141 /* A lambda-expression in template context is dependent. dependent_type_p is
27142 true for a lambda in the scope of a class or function template, but that
27143 doesn't cover all template contexts, like a default template argument. */
27147 /* A fold expression is type-dependent. */
27154 /* Some expression forms are never type-dependent. */
27167 /* The types of these expressions depends only on the type to which
27168 the cast occurs. */
27177 /* The types of these expressions depends only on the type created
27178 by the expression. */
27181 {
27182 /* For NEW_EXPR tree nodes created inside a template, either
27183 the object type itself or a TREE_LIST may appear as the
27184 operand 1. */
27187 /* This is an array type. We need to check array dimensions
27188 as well. */
27190 || value_dependent_expression_p
27192 /* Array type whose dimension has to be deduced. */
27196 else
27198 }
27201 {
27205 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
27206 contains an identifier associated by name lookup with one or more
27207 declarations declared with a dependent type, or...a
27208 nested-name-specifier or qualified-id that names a member of an
27209 unknown specialization. */
27212 }
27222 {
27223 tree elt;
27227 {
27230 }
27232 }
27234 /* A static data member of the current instantiation with incomplete
27235 array type is type-dependent, as the definition and specializations
27236 can have different bounds. */
27243 /* An array of unknown bound depending on a variadic parameter, eg:
27245 template<typename... Args>
27246 void foo (Args... args)
27247 {
27248 int arr[] = { args... };
27249 }
27251 template<int... vals>
27252 void bar ()
27253 {
27254 int arr[] = { vals... };
27255 }
27257 If the array has no length and has an initializer, it must be that
27258 we couldn't determine its length in cp_complete_array_type because
27259 it is dependent. */
27267 /* A function or variable template-id is type-dependent if it has any
27268 dependent template arguments. */
27272 {
27273 /* Consider the innermost template arguments, since those are the ones
27274 that come from the template-id; the template arguments for the
27275 enclosing class do not make it type-dependent unless they are used in
27276 the type of the decl. */
27278 && (any_dependent_template_arguments_p
27281 }
27283 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
27284 type-dependent. Checking this is important for functions with auto return
27285 type, which looks like a dependent type. */
27294 {
27298 }
27300 /* Always dependent, on the number of arguments if nothing else. */
27305 {
27310 {
27316 }
27317 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
27321 /* CO_AWAIT/YIELD_EXPR with unknown type is always dependent. */
27327 {
27332 }
27335 {
27342 }
27351 }
27353 /* The type of a non-type template parm declared with a placeholder type
27354 depends on the corresponding template argument, even though
27355 placeholders are not normally considered dependent. */
27362 /* Dependent type attributes might not have made it from the decl to
27363 the type yet. */
27369 }
27371 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
27372 type-dependent if the expression refers to a member of the current
27373 instantiation and the type of the referenced member is dependent, or the
27374 class member access expression refers to a member of an unknown
27375 specialization.
27377 This function returns true if the OBJECT in such a class member access
27378 expression is of an unknown specialization. */
27380 bool
27382 {
27383 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
27384 dependent. */
27389 }
27391 /* walk_tree callback function for instantiation_dependent_expression_p,
27392 below. Returns non-zero if a dependent subexpression is found. */
27394 static tree
27397 {
27399 {
27400 /* We don't have to worry about decltype currently because decltype
27401 of an instantiation-dependent expr is a dependent type. This
27402 might change depending on the resolution of DR 1172. */
27405 }
27408 {
27409 /* Don't treat an argument list as dependent just because it has no
27410 TREE_TYPE. */
27421 /* We'll check value-dependence separately. */
27424 /* Handle expressions with type operands. */
27429 {
27434 {
27437 else
27438 {
27441 }
27442 }
27444 }
27448 /* In a template, finish_class_member_access_expr creates a
27449 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
27450 type-dependent, so that we can check access control at
27451 instantiation time (PR 42277). See also Core issue 1273. */
27458 else
27461 /* Treat statement-expressions as dependent. */
27465 /* Treat requires-expressions as dependent. */
27470 /* Treat concept checks as dependent. */
27476 /* Treat concept checks as dependent. */
27488 }
27492 else
27494 }
27496 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
27497 sense defined by the ABI:
27499 "An expression is instantiation-dependent if it is type-dependent
27500 or value-dependent, or it has a subexpression that is type-dependent
27501 or value-dependent."
27503 Except don't actually check value-dependence for unevaluated expressions,
27504 because in sizeof(i) we don't care about the value of i. Checking
27505 type-dependence will in turn check value-dependence of array bounds/template
27506 arguments as needed. */
27508 bool
27510 {
27511 tree result;
27522 }
27524 /* As above, but also check value-dependence of the expression as a whole. */
27526 bool
27528 {
27530 || (processing_template_decl
27533 }
27535 /* Like type_dependent_expression_p, but it also works while not processing
27536 a template definition, i.e. during substitution or mangling. */
27538 bool
27540 {
27546 }
27548 /* Returns TRUE if ARGS contains a type-dependent expression. */
27550 bool
27552 {
27554 tree arg;
27557 {
27560 }
27562 }
27564 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
27565 expressions) contains any type-dependent expressions. */
27567 bool
27569 {
27575 }
27577 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
27578 expressions) contains any value-dependent expressions. */
27580 bool
27582 {
27588 }
27590 /* Returns TRUE if the ARG (a template argument) is dependent. */
27592 bool
27594 {
27598 /* Assume a template argument that was wrongly written by the user
27599 is dependent. This is consistent with what
27600 any_dependent_template_arguments_p [that calls this function]
27601 does. */
27611 {
27614 /* A member template of a dependent class is not necessarily
27615 type-dependent, but it is a dependent template argument because it
27616 will be a member of an unknown specialization to that template. */
27619 }
27621 {
27625 {
27628 }
27631 }
27634 else
27636 }
27638 /* Returns true if ARGS (a collection of template arguments) contains
27639 any types that require structural equality testing. */
27641 bool
27643 {
27653 {
27656 {
27662 {
27663 /* Look inside the argument pack. */
27666 }
27669 {
27682 }
27683 }
27684 }
27687 }
27689 /* Returns true if ARGS (a collection of template arguments) contains
27690 any dependent arguments. */
27692 bool
27694 {
27704 {
27709 }
27712 }
27714 /* Returns true if ARGS contains any errors. */
27716 bool
27718 {
27726 {
27729 else
27731 }
27737 {
27742 }
27745 }
27747 /* Returns TRUE if the template TMPL is type-dependent. */
27749 bool
27751 {
27753 {
27758 }
27760 /* Template template parameters are dependent. */
27764 /* So are names that have not been looked up. */
27768 }
27770 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
27772 bool
27774 {
27777 }
27779 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
27780 are dependent. */
27782 bool
27784 {
27791 {
27816 {
27820 }
27824 {
27828 {
27834 /* If this loop has a class iterator with != comparison
27835 with increment other than i++/++i/i--/--i, make sure the
27836 increment is constant. */
27839 {
27842 else
27846 }
27847 }
27848 }
27849 }
27852 }
27854 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
27855 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
27856 no such TYPE can be found. Note that this function peers inside
27857 uninstantiated templates and therefore should be used only in
27858 extremely limited situations. ONLY_CURRENT_P restricts this
27859 peering to the currently open classes hierarchy (which is required
27860 when comparing types). */
27862 tree
27864 {
27865 tree scope;
27866 tree name;
27867 tree decl;
27869 tree pushed_scope;
27870 tree result;
27875 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
27878 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
27879 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of a
27880 TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL
27881 representing the typedef. In that case TYPE_IDENTIFIER (type) is
27882 not the non-qualified identifier of the TYPENAME_TYPE anymore.
27883 So by getting the TYPE_IDENTIFIER of the _main declaration_ of
27884 the TYPENAME_TYPE instead, we avoid messing up with a possible
27885 typedef variant case. */
27888 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
27889 it first before we can figure out what NAME refers to. */
27891 {
27893 /* Given a class template A with a dependent base with nested type C,
27894 typedef typename A::C::C C will land us here, as trying to resolve
27895 the initial A::C leads to the local C typedef, which leads back to
27896 A::C::C. So we break the recursion now. */
27898 else
27900 }
27901 /* If we don't know what SCOPE refers to, then we cannot resolve the
27902 TYPENAME_TYPE. */
27905 /* If this is a typedef, we don't want to look inside (c++/11987). */
27908 /* If SCOPE isn't the template itself, it will not have a valid
27909 TYPE_FIELDS list. */
27911 /* scope is either the template itself or a compatible instantiation
27912 like X<T>, so look up the name in the original template. */
27914 /* If scope has no fields, it can't be a current instantiation. Check this
27915 before currently_open_class to avoid infinite recursion (71515). */
27918 /* If the SCOPE is not the current instantiation, there's no reason
27919 to look inside it. */
27922 /* Enter the SCOPE so that name lookup will be resolved as if we
27923 were in the class definition. In particular, SCOPE will no
27924 longer be considered a dependent type. */
27926 /* Look up the declaration. */
27928 tf_warning_or_error);
27932 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
27933 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
27939 {
27943 }
27946 {
27947 /* Obtain the template and the arguments. */
27950 {
27951 /* We get here with a plain identifier because a previous tentative
27952 parse of the nested-name-specifier as part of a ptr-operator saw
27953 ::template X<A>. The use of ::template is necessary in a
27954 ptr-operator, but wrong in a declarator-id.
27956 [temp.names]: In a qualified-id of a declarator-id, the keyword
27957 template shall not appear at the top level. */
27961 }
27963 /* Instantiate the template. */
27969 }
27971 /* Leave the SCOPE. */
27975 /* If we failed to resolve it, return the original typename. */
27979 /* If lookup found a typename type, resolve that too. */
27981 {
27982 /* Ill-formed programs can cause infinite recursion here, so we
27983 must catch that. */
27987 }
27989 /* Qualify the resulting type. */
27995 }
27997 /* EXPR is an expression which is not type-dependent. Return a proxy
27998 for EXPR that can be used to compute the types of larger
27999 expressions containing EXPR. */
28001 tree
28003 {
28005 tree inner_expr;
28007 /* When checking, try to get a constant value for all non-dependent
28008 expressions in order to expose bugs in *_dependent_expression_p
28009 and constexpr. This can affect code generation, see PR70704, so
28010 only do this for -fchecking=2. */
28013 /* Don't do this during nsdmi parsing as it can lead to
28014 unexpected recursive instantiations. */
28016 /* Don't do this during concept processing either and for
28017 the same reason. */
28023 /* Preserve OVERLOADs; the functions must be available to resolve
28024 types. */
28035 /* There is no need to return a proxy for a variable or enumerator. */
28038 /* Preserve string constants; conversions from string constants to
28039 "char *" are allowed, even though normally a "const char *"
28040 cannot be used to initialize a "char *". */
28043 /* Preserve void and arithmetic constants, as an optimization -- there is no
28044 reason to create a new node. */
28049 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
28050 There is at least one place where we want to know that a
28051 particular expression is a throw-expression: when checking a ?:
28052 expression, there are special rules if the second or third
28053 argument is a throw-expression. */
28057 /* Don't wrap an initializer list, we need to be able to look inside. */
28061 /* Don't wrap a dummy object, we need to be able to test for it. */
28080 /* If the type is unknown, it can't really be non-dependent */
28083 /* Otherwise, build a NON_DEPENDENT_EXPR. */
28086 }
28088 /* ARGS is a vector of expressions as arguments to a function call.
28089 Replace the arguments with equivalent non-dependent expressions.
28090 This modifies ARGS in place. */
28092 void
28094 {
28096 tree arg;
28099 {
28103 }
28104 }
28106 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
28107 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
28108 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
28110 static tree
28112 {
28127 }
28129 tree
28131 {
28133 }
28135 tree
28137 {
28139 }
28141 /* Return a C++17 deduction placeholder for class template TMPL. */
28143 tree
28145 {
28148 /* Our canonical type depends on the placeholder. */
28151 }
28153 /* True iff T is a C++17 class template deduction placeholder. */
28155 bool
28157 {
28159 }
28161 /* Make a "constrained auto" type-specifier. This is an auto or
28162 decltype(auto) type with constraints that must be associated after
28163 deduction. The constraint is formed from the given concept CON
28164 and its optional sequence of template arguments ARGS.
28166 TYPE must be the result of make_auto_type or make_decltype_auto_type. */
28168 static tree
28170 {
28171 /* Build the constraint. */
28183 /* Our canonical type depends on the constraint. */
28186 /* Attach the constraint to the type declaration. */
28188 }
28190 /* Make a "constrained auto" type-specifier. */
28192 tree
28194 {
28197 }
28199 /* Make a "constrained decltype(auto)" type-specifier. */
28201 tree
28203 {
28206 }
28208 /* Returns true if the placeholder type constraint T has any dependent
28209 (explicit) template arguments. */
28211 static bool
28213 {
28218 {
28221 }
28228 }
28230 /* Build and return a concept definition. Like other templates, the
28231 CONCEPT_DECL node is wrapped by a TEMPLATE_DECL. This returns the
28232 the TEMPLATE_DECL. */
28234 tree
28236 {
28242 /* A concept-definition shall not have associated constraints. */
28244 {
28247 }
28249 /* A concept-definition shall appear in namespace scope. Templates
28250 aren't allowed in block scope, so we only need to check for class
28251 scope. */
28253 {
28256 }
28258 /* Initially build the concept declaration; its type is bool. */
28265 /* Push the enclosing template. */
28267 }
28269 /* Given type ARG, return std::initializer_list<ARG>. */
28271 static tree
28273 {
28277 {
28281 "deducing from brace-enclosed initializer list"
28285 }
28291 }
28293 /* Replace auto in TYPE with std::initializer_list<auto>. */
28295 static tree
28297 {
28304 }
28306 /* Hash traits for hashing possibly constrained 'auto'
28307 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
28310 {
28313 };
28315 /* Hash the 'auto' T. */
28317 inline hashval_t
28319 {
28321 /* Matching constrained-type-specifiers denote the same template
28322 parameter, so hash the constraint. */
28324 else
28325 /* But unconstrained autos are all separate, so just hash the pointer. */
28327 }
28329 /* Compare two 'auto's. */
28333 {
28340 /* Two unconstrained autos are distinct. */
28345 }
28347 /* for_each_template_parm callback for extract_autos: if t is a (possibly
28348 constrained) auto, add it to the vector. */
28350 static int
28352 {
28355 {
28356 /* All the autos were built with index 0; fix that up now. */
28360 /* If this is a repeated constrained-type-specifier, use the index we
28361 chose before. */
28363 else
28364 {
28365 /* Otherwise this is new, so use the current count. */
28368 }
28370 }
28372 /* Always keep walking. */
28374 }
28376 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
28377 says they can appear anywhere in the type. */
28379 static tree
28381 {
28390 {
28395 }
28398 }
28400 /* The stem for deduction guide names. */
28403 /* Return the name for a deduction guide for class template TMPL. */
28405 tree
28407 {
28418 }
28420 /* True if NAME is the name of a deduction guide. */
28422 bool
28424 {
28428 }
28430 /* True if FN is a deduction guide. */
28432 bool
28434 {
28439 }
28441 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
28443 bool
28445 {
28452 }
28454 /* True if FN is a guide generated from a constructor template. */
28456 bool
28458 {
28466 }
28468 /* True if FN is an aggregate initialization guide or the copy deduction
28469 guide. */
28471 bool
28473 {
28477 /* Explicitly declared. */
28480 /* Derived from a constructor. */
28483 }
28485 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
28486 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
28487 template parameter types. Note that the handling of template template
28488 parameters relies on current_template_parms being set appropriately for the
28489 new template. */
28491 static tree
28494 {
28500 tree newtype;
28503 {
28510 }
28511 else
28512 {
28515 {
28516 // Substitute once to fix references to other template parameters.
28519 // Now substitute again to reduce the level of the auto.
28522 }
28523 else
28526 }
28528 tree newdecl
28533 tree newidx;
28536 {
28545 else
28549 {
28554 // First create a copy (ttargs) of tsubst_args with an
28555 // additional level for the template template parameter's own
28556 // template parameters (ttparms).
28557 tree ttparms = (INNERMOST_TEMPLATE_PARMS
28565 // Substitute ttargs into ttparms to fix references to
28566 // other template parameters.
28569 // Now substitute again with args based on tparms, to reduce
28570 // the level of the ttparms.
28573 complain);
28574 // Finally, tack the adjusted parms onto tparms.
28576 current_template_parms);
28578 }
28579 }
28580 else
28581 {
28583 tree newconst
28595 }
28598 }
28600 /* As rewrite_template_parm, but for the whole TREE_LIST representing a
28601 template parameter. */
28603 static tree
28606 {
28621 }
28623 /* Returns a C++17 class deduction guide template based on the constructor
28624 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
28625 guide, REFERENCE_TYPE for an implicit copy/move guide, or TREE_LIST for an
28626 aggregate initialization guide. OUTER_ARGS are the template arguments
28627 for the enclosing scope of the class. */
28629 static tree
28631 {
28635 location_t loc;
28639 {
28643 }
28646 {
28648 {
28652 else
28654 }
28657 else
28667 }
28668 else
28669 {
28673 fn_tmpl
28681 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
28682 fully specialized args for the enclosing class. Strip those off, as
28683 the deduction guide won't have those template parameters. */
28686 /* Discard the 'this' parameter. */
28694 {
28697 /* For a member template constructor, we need to flatten the two
28698 template parameter lists into one, and then adjust the function
28699 signature accordingly. This gets...complicated. */
28702 /* For a member template we should have two levels of parms/args, one
28703 for the class and one for the constructor. We stripped
28704 specialized args for further enclosing classes above. */
28708 /* Template args for translating references to the two-level template
28709 parameters into references to the one-level template parameters we
28710 are creating. */
28715 /* Template parms for the constructor template. */
28718 /* Template parms for the class template. */
28722 /* Template parms for the deduction guide start as a copy of the
28723 template parms for the class. We set current_template_parms for
28724 lookup_template_class_1. */
28730 /* Now we need to rewrite the constructor parms to append them to the
28731 class parms. */
28733 {
28737 tree newelt
28743 }
28745 /* Now we have a final set of template parms to substitute into the
28746 function signature. */
28753 {
28755 /* FIXME: We'd like to avoid substituting outer template
28756 arguments into the constraint ahead of time, but the
28757 construction of tsubst_args assumes that outer arguments
28758 are already substituted in. */
28761 }
28763 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped if
28764 cp_unevaluated_operand. */
28765 cp_evaluated ev;
28768 }
28769 else
28770 {
28771 /* Substitute in the same arguments to rewrite class members into
28772 references to members of an unknown specialization. */
28773 cp_evaluated ev;
28777 {
28779 /* FIXME: As above. */
28782 }
28783 }
28788 }
28791 {
28792 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
28796 }
28800 FUNCTION_DECL,
28815 }
28817 /* Add to LIST the member types for the reshaped initializer CTOR. */
28819 static tree
28821 {
28825 {
28829 /* As in reshape_init_r, a non-aggregate or array-of-dependent-bound
28830 type gets a single initializer. */
28834 {
28840 }
28844 /* Give the trailing pack expansion parameter a default argument to
28845 match aggregate initialization behavior, even if we deduce the
28846 length of the pack separately to more than we have initializers. */
28848 /* if ei is of array type and xi is a braced-init-list or string literal,
28849 Ti is an rvalue reference to the declared type of ei */
28854 {
28856 ftype = cp_build_qualified_type
28858 ftype = (cp_build_reference_type
28860 }
28862 }
28865 }
28867 /* Return whether ETYPE is, or is derived from, a specialization of TMPL. */
28869 static bool
28871 {
28877 tree tparms = (INNERMOST_TEMPLATE_PARMS
28884 }
28886 /* Return a C++20 aggregate deduction candidate for TYPE initialized from
28887 INIT. */
28889 static tree
28891 {
28898 /* We might be creating a guide for a class member template, e.g.,
28900 template<typename U> struct A {
28901 template<typename T> struct B { T t; };
28902 };
28904 At this point, A will have been instantiated. Below, we need to
28905 use both A<U>::B<T> (TEMPLATE_TYPE) and A<int>::B<T> (TYPE) types. */
28906 const bool member_template_p
28910 tree template_type = (member_template_p
28916 /* No aggregate candidate for copy-initialization. */
28918 {
28922 }
28924 /* If we encounter a problem, we just won't add the candidate. */
28929 {
28934 /* If we're creating a deduction guide for a member class template,
28935 we've used the original template pattern type for the reshape_init
28936 above; this is done because we want PARMS to be a template parameter
28937 type, something that can be deduced when used as a function template
28938 parameter. At this point the outer class template has already been
28939 partially instantiated (we deferred the deduction until the enclosing
28940 scope is non-dependent). Therefore we have to partially instantiate
28941 PARMS, so that its template level is properly reduced and we don't get
28942 mismatches when deducing types using the guide with PARMS. */
28945 }
28947 {
28950 len;
28952 {
28958 }
28959 }
28960 else
28961 /* Aggregate initialization doesn't apply to an initializer expression. */
28965 {
28971 }
28974 }
28976 /* UGUIDES are the deduction guides for the underlying template of alias
28977 template TMPL; adjust them to be deduction guides for TMPL. */
28979 static tree
28981 {
28982 /* [over.match.class.deduct]: When resolving a placeholder for a deduced
28983 class type (9.2.8.2) where the template-name names an alias template A,
28984 the defining-type-id of A must be of the form
28986 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
28988 as specified in 9.2.8.2. The guides of A are the set of functions or
28989 function templates formed as follows. For each function or function
28990 template f in the guides of the template named by the simple-template-id
28991 of the defining-type-id, the template arguments of the return type of f
28992 are deduced from the defining-type-id of A according to the process in
28993 13.10.2.5 with the exception that deduction does not fail if not all
28994 template arguments are deduced. Let g denote the result of substituting
28995 these deductions into f. If substitution succeeds, form a function or
28996 function template f' with the following properties and add it to the set
28997 of guides of A:
28999 * The function type of f' is the function type of g.
29001 * If f is a function template, f' is a function template whose template
29002 parameter list consists of all the template parameters of A (including
29003 their default template arguments) that appear in the above deductions or
29004 (recursively) in their default template arguments, followed by the
29005 template parameters of f that were not deduced (including their default
29006 template arguments), otherwise f' is not a function template.
29008 * The associated constraints (13.5.2) are the conjunction of the
29009 associated constraints of g and a constraint that is satisfied if and only
29010 if the arguments of A are deducible (see below) from the return type.
29012 * If f is a copy deduction candidate (12.4.1.8), then f' is considered to
29013 be so as well.
29015 * If f was generated from a deduction-guide (12.4.1.8), then f' is
29016 considered to be so as well.
29018 * The explicit-specifier of f' is the explicit-specifier of g (if
29019 any). */
29021 /* This implementation differs from the above in two significant ways:
29023 1) We include all template parameters of A, not just some.
29024 2) The added constraint is same_type instead of deducible.
29026 I believe that while it's probably possible to construct a testcase that
29027 behaves differently with this simplification, it should have the same
29028 effect for real uses. Including all template parameters means that we
29029 deduce all parameters of A when resolving the call, so when we're in the
29030 constraint we don't need to deduce them again, we can just check whether
29031 the deduction produced the desired result. */
29040 {
29047 {
29051 /* Deduce template arguments for f from the type-id of A. */
29059 /* The number of parms for f' is the number of parms for A plus
29060 non-deduced parms of f. */
29068 /* First copy over the parms of A. */
29071 /* Now rewrite the non-deduced parms of f. */
29074 {
29082 }
29085 /* Substitute the deduced arguments plus the rewritten template
29086 parameters into f to get g. This covers the type, copyness,
29087 guideness, and explicit-specifier. */
29099 /* Substitute the associated constraints. */
29106 /* Add a constraint that the return type matches the instantiation of
29107 A with the same template arguments. */
29110 /* FIXME this should mean they don't compare as equivalent. */
29112 {
29115 }
29118 {
29121 }
29122 }
29123 else
29124 {
29125 /* For a non-template deduction guide, if the arguments of A aren't
29126 deducible from the return type, don't add the candidate. */
29134 }
29137 }
29140 }
29142 /* Return artificial deduction guides built from the constructors of class
29143 template TMPL. */
29145 static tree
29147 {
29152 {
29155 }
29160 {
29161 /* Skip inherited constructors. */
29167 }
29169 /* Add implicit default constructor deduction guide. */
29171 {
29173 complain);
29175 }
29177 /* Add copy guide. */
29178 {
29181 complain);
29183 }
29186 }
29190 /* Return the non-aggregate deduction guides for deducible template TMPL. The
29191 aggregate candidate is added separately because it depends on the
29192 initializer. Set ANY_DGUIDES_P if we find a non-implicit deduction
29193 guide. */
29195 static tree
29197 {
29200 {
29204 complain);
29205 }
29206 else
29207 {
29213 else
29215 }
29217 /* Cache the deduction guides for a template. We also remember the result of
29218 lookup, and rebuild everything if it changes; should be very rare. */
29222 {
29226 }
29227 else
29228 {
29231 }
29236 else
29237 {
29241 }
29245 }
29247 /* Return whether TMPL is a (class template argument-) deducible template. */
29249 bool
29251 {
29252 /* A deducible template is either a class template or is an alias template
29253 whose defining-type-id is of the form
29255 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
29257 where the nested-name-specifier (if any) is non-dependent and the
29258 template-name of the simple-template-id names a deducible template. */
29269 }
29271 /* Deduce template arguments for the class template placeholder PTYPE for
29272 template TMPL based on the initializer INIT, and return the resulting
29273 type. */
29275 static tree
29278 {
29279 /* We should have handled this in the caller. */
29283 /* Wait until the enclosing scope is non-dependent. */
29288 /* Initializing one placeholder from another. */
29298 /* Look through alias templates that just rename another template. */
29301 {
29305 }
29307 {
29312 }
29314 /* Wait until the initializer is non-dependent. */
29328 {
29333 {
29334 /* As an exception, the first phase in 16.3.1.7 (considering the
29335 initializer list as a single argument) is omitted if the
29336 initializer list consists of a single expression of type cv U,
29337 where U is a specialization of C or a class derived from a
29338 specialization of C. */
29342 }
29345 else
29347 }
29350 else
29353 /* Do this now to avoid problems with erroneous args later on. */
29363 /* Prune explicit deduction guides in copy-initialization context (but
29364 not copy-list-initialization). */
29367 {
29373 {
29374 /* Found a nonconverting guide, prune the candidates. */
29381 }
29382 }
29390 /* If this is list-initialization and the class has a list constructor, first
29391 try deducing from the list as a single argument, as [over.match.list]. */
29395 {
29399 }
29401 {
29405 {
29406 /* That didn't work, now try treating the list as a sequence of
29407 arguments. */
29410 }
29411 }
29414 {
29416 " of %qT, as it has no non-explicit deduction guides or "
29419 }
29421 {
29425 }
29431 {
29433 {
29439 }
29441 }
29442 /* [over.match.list]/1: In copy-list-initialization, if an explicit
29443 constructor is chosen, the initialization is ill-formed. */
29445 {
29447 {
29449 {
29450 // TODO: Pass down location from cp_finish_decl.
29452 "explicit deduction guide selected in "
29457 }
29459 }
29460 }
29462 /* If CTAD succeeded but the type doesn't have any explicit deduction
29463 guides, this deduction might not be what the user intended. */
29465 {
29469 "%qT may not intend to support class template argument "
29473 }
29477 }
29479 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
29480 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
29481 The CONTEXT determines the context in which auto deduction is performed
29482 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
29484 OUTER_TARGS is used during template argument deduction (context == adc_unify)
29485 to properly substitute the result. It's also used in the adc_unify and
29486 adc_requirement contexts to communicate the the necessary template arguments
29487 to satisfaction. OUTER_TARGS is ignored in other contexts.
29489 For partial-concept-ids, extra args may be appended to the list of deduced
29490 template arguments prior to determining constraint satisfaction. */
29492 tree
29496 {
29502 /* Defining a subset of type-dependent expressions that we can deduce
29503 from ahead of time isn't worth the trouble. */
29506 /* Similarly, we can't deduce from another undeduced decl. */
29510 /* We may be doing a partial substitution, but we still want to replace
29511 auto_node. */
29515 /* C++17 class template argument deduction. */
29519 /* Nothing we can do with this, even in deduction context. */
29522 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
29523 with either a new invented type template parameter U or, if the
29524 initializer is a braced-init-list (8.5.4), with
29525 std::initializer_list<U>. */
29527 {
29532 else
29533 {
29535 {
29539 "for deduction to %<std::initializer_list%>, use copy-"
29541 }
29543 }
29544 }
29550 {
29551 /* We don't recurse here because we can't deduce from a nested
29552 initializer_list. */
29556 }
29557 else
29560 tree targs;
29565 {
29566 /* [dcl.struct.bind]/1 - if decomposition declaration has no ref-qualifiers
29567 and initializer has array type, deduce cv-qualified array type. */
29570 }
29572 {
29586 /* FIXME: These errors ought to be diagnosed at parse time. */
29588 {
29592 }
29594 {
29598 }
29599 }
29600 else
29601 {
29606 tree tparms;
29610 else
29611 {
29615 }
29619 DEDUCE_CALL,
29622 {
29624 /* Try again at instantiation time. */
29628 /* If type is error_mark_node a diagnostic must have been
29629 emitted by now. Also, having a mention to '<type error>'
29630 in the diagnostic is not really useful to the user. */
29631 {
29634 && (auto_node
29638 else
29641 DEDUCE_CALL,
29643 }
29645 }
29646 }
29648 /* Check any placeholder constraints against the deduced type. */
29652 {
29654 {
29659 /* If the constraint is dependent, we need to wait until
29660 instantiation time to resolve the placeholder. */
29663 }
29668 && current_function_decl
29674 /* HACK: Compensate for callers not always communicating all levels of
29675 outer template arguments by filling in the outermost missing levels
29676 with dummy levels before checking satisfaction. We'll still crash
29677 if the constraint depends on a template argument belonging to one of
29678 these missing levels, but this hack otherwise allows us to handle a
29679 large subset of possible constraints (including all non-dependent
29680 constraints). */
29683 {
29688 }
29691 {
29693 {
29694 auto_diagnostic_group d;
29696 {
29714 }
29716 }
29718 }
29719 }
29722 /* The outer template arguments are already substituted into type
29729 }
29731 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
29732 result. */
29734 tree
29736 {
29738 {
29741 }
29745 {
29746 /* In an abbreviated function template we didn't know we were dealing
29747 with a function template when we saw the auto return type, so rebuild
29748 the return type using an auto with the correct level. */
29753 auto_vec);
29754 /* Also rebuild the constraint info in terms of the new auto. */
29762 }
29764 }
29766 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
29767 'decltype(auto)' or a deduced class template. */
29769 bool
29771 {
29776 else
29778 }
29780 /* for_each_template_parm callback for type_uses_auto. */
29782 int
29784 {
29786 }
29788 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
29789 a use of `auto'. Returns NULL_TREE otherwise. */
29791 tree
29793 {
29797 {
29798 /* The Concepts TS allows multiple autos in one type-specifier; just
29799 return the first one we find, do_auto_deduction will collect all of
29800 them. */
29804 else
29806 }
29807 else
29809 }
29811 /* Report ill-formed occurrences of auto types in ARGUMENTS. If
29812 concepts are enabled, auto is acceptable in template arguments, but
29813 only when TEMPL identifies a template class. Return TRUE if any
29814 such errors were reported. */
29816 bool
29818 {
29819 /* If there were previous errors, nevermind. */
29823 /* If TMPL is an identifier, we're parsing and we can't tell yet
29824 whether TMPL is supposed to be a type, a function or a variable.
29825 We'll only be able to tell during template substitution, so we
29826 expect to be called again then. If concepts are enabled and we
29827 know we have a type, we're ok. */
29835 /* Quickly search for any occurrences of auto; usually there won't
29836 be any, and then we'll avoid allocating the vector. */
29844 {
29849 }
29852 }
29854 /* Recursively walk over && expressions searching for EXPR. Return a reference
29855 to that expression. */
29858 {
29862 {
29867 }
29869 }
29871 /* Convert the generic type parameters in PARM that match the types given in the
29872 range [START_IDX, END_IDX) from the current_template_parms into generic type
29873 packs. */
29875 tree
29877 {
29888 {
29889 /* Create a distinct parameter pack type from the current parm and add it
29890 to the replacement args to tsubst below into the generic function
29891 parameter. */
29905 /* Replace the current template parameter with new pack. */
29908 /* Surgically adjust the associated constraint of adjusted parameter
29909 and it's corresponding contribution to the current template
29910 requirements. */
29912 {
29918 /* If there was a constraint, we also need to replace that in
29919 the template requirements, which we've already built. */
29923 }
29924 }
29930 /* If there are more levels then build up the replacement with the outer
29931 template parms. */
29935 replacement);
29938 }
29940 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
29941 0..N-1. */
29943 void
29945 {
29948 integer_type_node,
29949 NULL_TREE),
29953 CP_BUILT_IN_INTEGER_PACK);
29954 }
29956 /* Walk the decl or type specialization table calling FN on each
29957 entry. */
29959 void
29963 {
29969 }
29971 /* Lookup the specialization of *ELT, in the decl or type
29972 specialization table. Return the SPEC that's already there, or
29973 NULL if nothing. */
29975 tree
29977 {
29987 }
29989 /* Return flags encoding whether SPEC is on the instantiation and/or
29990 specialization lists of TMPL. */
29992 unsigned
29994 {
30000 {
30003 }
30008 /* Only need to search if DECL is a partial specialization. */
30012 {
30015 }
30018 }
30020 /* Add a new specialization described by SPEC. DECL is the
30021 maybe-template decl and FLAGS is as returned from
30022 get_mergeable_specialization_flags. */
30024 void
30027 {
30030 {
30039 {
30042 }
30043 }
30046 {
30049 /* We don't distinguish different constrained partial type
30050 specializations, so there could be duplicates. Everything else
30051 must be new. */
30053 {
30059 }
30060 }
30067 {
30068 /* A partial specialization. */
30073 }
30074 }
30076 /* Set up the hash tables for template instantiations. */
30078 void
30080 {
30086 }
30088 /* Print stats about the template hash tables for -fstats. */
30090 void
30092 {
30101 }
30103 #if CHECKING_P
30107 /* Verify that build_non_dependent_expr () works, for various expressions,
30108 and that location wrappers don't affect the results. */
30110 static void
30112 {
30115 /* Verify constants, without and with location wrappers. */
30132 }
30134 /* Verify that type_dependent_expression_p () works correctly, even
30135 in the presence of location wrapper nodes. */
30137 static void
30139 {
30144 /* If no templates are involved, nothing is type-dependent. */
30150 /* Within a template, an unresolved name is always type-dependent. */
30153 /* Ensure it copes with NULL_TREE and errors. */
30157 /* A USING_DECL in a template should be type-dependent, even if wrapped
30158 with a location wrapper (PR c++/83799). */
30167 }
30169 /* Run all of the selftests within this file. */
30171 void
30173 {
30176 }