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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 };
224 /* Make the current scope suitable for access checking when we are
225 processing T. T can be FUNCTION_DECL for instantiated function
226 template, VAR_DECL for static member variable, or TYPE_DECL for
227 for a class or alias template (needed by instantiate_decl). */
229 void
231 {
243 /* An artificial deduction guide should have the same access as
244 the constructor. */
246 else
250 {
253 }
254 }
256 /* Restore the scope set up by push_access_scope. T is the node we
257 are processing. */
259 void
261 {
271 else
273 }
275 /* Do any processing required when DECL (a member template
276 declaration) is finished. Returns the TEMPLATE_DECL corresponding
277 to DECL, unless it is a specialization, in which case the DECL
278 itself is returned. */
280 tree
282 {
289 {
290 tree type;
298 {
302 }
304 }
309 {
311 {
314 }
315 else
317 }
318 else
323 }
325 /* Create a template info node. */
327 tree
329 {
334 }
336 /* Return the template info node corresponding to T, whatever T is. */
338 tree
340 {
362 }
364 /* Returns the template nesting level of the indicated class TYPE.
366 For example, in:
367 template <class T>
368 struct A
369 {
370 template <class U>
371 struct B {};
372 };
374 A<T>::B<U> has depth two, while A<T> has depth one.
375 Both A<T>::B<int> and A<int>::B<U> have depth one, if
376 they are instantiations, not specializations.
378 This function is guaranteed to return 0 if passed NULL_TREE so
379 that, for example, `template_class_depth (current_class_type)' is
380 always safe. */
382 int
384 {
388 {
396 {
399 else
401 }
404 else
406 }
409 }
411 /* Return TRUE if NODE instantiates a template that has arguments of
412 its own, be it directly a primary template or indirectly through a
413 partial specializations. */
414 static bool
416 {
428 /* So now we know we have a specialization, but it could be a full
429 or a partial specialization. To tell which, compare the depth of
430 its template arguments with those of its context. */
439 }
441 /* Subroutine of maybe_begin_member_template_processing.
442 Returns true if processing DECL needs us to push template parms. */
444 static bool
446 {
452 }
454 /* Subroutine of maybe_begin_member_template_processing.
455 Push the template parms in PARMS, starting from LEVELS steps into the
456 chain, and ending at the beginning, since template parms are listed
457 innermost first. */
459 static void
461 {
469 current_template_parms
475 NULL);
477 {
486 {
493 /* Push the CONST_DECL. */
499 }
500 }
501 }
503 /* Restore the template parameter context for a member template, a
504 friend template defined in a class definition, or a non-template
505 member of template class. */
507 void
509 {
510 tree parms;
515 {
518 /* Disregard full specializations (c++/60999). */
521 }
524 {
529 {
532 }
535 }
537 /* Remember how many levels of template parameters we pushed so that
538 we can pop them later. */
540 }
542 /* Undo the effects of maybe_begin_member_template_processing. */
544 void
546 {
555 {
559 }
560 }
562 /* Return a new template argument vector which contains all of ARGS,
563 but has as its innermost set of arguments the EXTRA_ARGS. */
565 tree
567 {
568 tree new_args;
586 }
588 /* Like add_to_template_args, but only the outermost ARGS are added to
589 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
590 (EXTRA_ARGS) levels are added. This function is used to combine
591 the template arguments from a partial instantiation with the
592 template arguments used to attain the full instantiation from the
593 partial instantiation.
595 If ARGS is a TEMPLATE_DECL, use its parameters as args. */
597 tree
599 {
600 tree new_args;
605 {
608 }
610 /* If there are more levels of EXTRA_ARGS than there are ARGS,
611 something very fishy is going on. */
614 /* If *all* the new arguments will be the EXTRA_ARGS, just return
615 them. */
619 /* For the moment, we make ARGS look like it contains fewer levels. */
624 /* Now, we restore ARGS to its full dimensions. */
628 }
630 /* Return the N levels of innermost template arguments from the ARGS. */
632 tree
634 {
635 tree new_args;
641 /* If N is 1, just return the innermost set of template arguments. */
645 /* If we're not removing anything, just return the arguments we were
646 given. */
652 /* Make a new set of arguments, not containing the outer arguments. */
659 }
661 /* The inverse of get_innermost_template_args: Return all but the innermost
662 EXTRA_LEVELS levels of template arguments from the ARGS. */
664 static tree
666 {
667 tree new_args;
673 /* If N is 1, just return the outermost set of template arguments. */
677 /* If we're not removing anything, just return the arguments we were
678 given. */
683 /* Make a new set of arguments, not containing the inner arguments. */
690 }
692 /* We've got a template header coming up; push to a new level for storing
693 the parms. */
695 void
697 {
698 /* We use a non-tag-transparent scope here, which causes pushtag to
699 put tags in this scope, rather than in the enclosing class or
700 namespace scope. This is the right thing, since we want
701 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
702 global template class, push_template_decl handles putting the
703 TEMPLATE_DECL into top-level scope. For a nested template class,
704 e.g.:
706 template <class T> struct S1 {
707 template <class T> struct S2 {};
708 };
710 pushtag contains special code to insert the TEMPLATE_DECL for S2
711 at the right scope. */
717 /* Add a dummy parameter level while we process the parameter list. */
718 current_template_parms
721 current_template_parms);
722 }
724 /* This routine is called when a specialization is declared. If it is
725 invalid to declare a specialization here, an error is reported and
726 false is returned, otherwise this routine will return true. */
728 static bool
730 {
733 /* [temp.expl.spec]
735 An explicit specialization shall be declared in the namespace of
736 which the template is a member, or, for member templates, in the
737 namespace of which the enclosing class or enclosing class
738 template is a member. An explicit specialization of a member
739 function, member class or static data member of a class template
740 shall be declared in the namespace of which the class template
741 is a member. */
743 {
746 }
748 /* [temp.expl.spec]
750 In an explicit specialization declaration for a member of a class
751 template or a member template that appears in namespace scope,
752 the member template and some of its enclosing class templates may
753 remain unspecialized, except that the declaration shall not
754 explicitly specialize a class member template if its enclosing
755 class templates are not explicitly specialized as well. */
757 {
760 }
763 }
765 /* We've just seen template <>. */
767 bool
769 {
773 }
775 /* Called at then end of processing a declaration preceded by
776 template<>. */
778 void
780 {
783 }
785 /* Any template <>'s that we have seen thus far are not referring to a
786 function specialization. */
788 void
790 {
793 }
795 /* We've just seen a template header. If SPECIALIZATION is nonzero,
796 it was of the form template <>. */
798 static void
800 {
802 template_header_count++;
803 }
805 /* We're beginning an explicit instantiation. */
807 void
809 {
812 }
815 void
817 {
820 }
822 /* An explicit specialization or partial specialization of TMPL is being
823 declared. Check that the namespace in which the specialization is
824 occurring is permissible. Returns false iff it is invalid to
825 specialize TMPL in the current namespace. */
827 static bool
829 {
832 /* [tmpl.expl.spec]
834 An explicit specialization shall be declared in a namespace enclosing the
835 specialized template. An explicit specialization whose declarator-id is
836 not qualified shall be declared in the nearest enclosing namespace of the
837 template, or, if the namespace is inline (7.3.1), any namespace from its
838 enclosing namespace set. */
841 {
844 }
847 /* Same or enclosing namespace. */
849 else
850 {
851 auto_diagnostic_group d;
857 }
858 }
860 /* SPEC is an explicit instantiation. Check that it is valid to
861 perform this explicit instantiation in the current namespace. */
863 static void
865 {
866 tree ns;
868 /* DR 275: An explicit instantiation shall appear in an enclosing
869 namespace of its template. */
875 }
877 /* Returns the type of a template specialization only if that
878 specialization needs to be defined. Otherwise (e.g., if the type has
879 already been defined), the function returns NULL_TREE. */
881 static tree
883 {
884 /* An implicit instantiation of an incomplete type implies
885 the definition of a new class template.
887 template<typename T>
888 struct S;
890 template<typename T>
891 struct S<T*>;
893 Here, S<T*> is an implicit instantiation of S whose type
894 is incomplete. */
898 /* It can also be the case that TYPE is a completed specialization.
899 Continuing the previous example, suppose we also declare:
901 template<typename T>
902 requires Integral<T>
903 struct S<T*>;
905 Here, S<T*> refers to the specialization S<T*> defined
906 above. However, we need to differentiate definitions because
907 we intend to define a new partial specialization. In this case,
908 we rely on the fact that the constraints are different for
909 this declaration than that above.
911 Note that we also get here for injected class names and
912 late-parsed template definitions. We must ensure that we
913 do not create new type declarations for those cases. */
915 {
919 /* If there are no template parameters, this cannot be a new
920 partial template specialization? */
924 /* The injected-class-name is not a new partial specialization. */
928 /* If the constraints are not the same as those of the primary
929 then, we can probably create a new specialization. */
933 {
937 }
939 /* Also, if there's a pre-existing specialization with matching
940 constraints, then this also isn't new. */
943 {
951 }
953 /* Create a new type node (and corresponding type decl)
954 for the newly declared specialization. */
959 /* We only need a separate type node for storing the definition of this
960 partial specialization; uses of S<T*> are unconstrained, so all are
961 equivalent. So keep TYPE_CANONICAL the same. */
964 /* Build the corresponding type decl. */
975 }
978 }
980 /* The TYPE is being declared. If it is a template type, that means it
981 is a partial specialization. Do appropriate error-checking. */
983 tree
985 {
986 tree context;
991 /* A lambda that appears in specialization context is not itself a
992 specialization. */
996 /* An injected-class-name is not a specialization. */
1001 {
1005 }
1010 {
1016 else
1019 }
1021 {
1022 /* This is for ordinary explicit specialization and partial
1023 specialization of a template class such as:
1025 template <> class C<int>;
1027 or:
1029 template <class T> class C<T*>;
1031 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
1034 {
1041 {
1046 }
1047 }
1053 /* Trying to define a specialization either without a template<> header
1054 or in an inappropriate place. We've already given an error, so just
1055 bail now so we don't actually define the specialization. */
1057 }
1063 {
1064 /* This is for an explicit specialization of member class
1065 template according to [temp.expl.spec/18]:
1067 template <> template <class U> class C<int>::D;
1069 The context `C<int>' must be an implicit instantiation.
1070 Otherwise this is just a member class template declared
1071 earlier like:
1073 template <> class C<int> { template <class U> class D; };
1074 template <> template <class U> class C<int>::D;
1076 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1077 while in the second case, `C<int>::D' is a primary template
1078 and `C<T>::D' may not exist. */
1082 {
1083 tree t;
1088 {
1091 type))
1094 }
1096 /* Check for invalid specialization after instantiation:
1098 template <> template <> class C<int>::D<int>;
1099 template <> template <class U> class C<int>::D; */
1103 {
1107 {
1108 /* We already have a full specialization of this partial
1109 instantiation, or a full specialization has been
1110 looked up but not instantiated. Reassign it to the
1111 new member specialization template. */
1112 spec_entry elt;
1125 spec_entry **slot
1130 }
1131 else
1132 /* But if we've had an implicit instantiation, that's a
1133 problem ([temp.expl.spec]/6). */
1136 }
1138 /* Mark TYPE as a specialization. And as a result, we only
1139 have one level of template argument for the innermost
1140 class template. */
1145 }
1146 }
1148 {
1149 /* Someday C++0x may allow for enum template specialization. */
1154 else
1155 {
1158 }
1159 }
1162 }
1164 /* Returns nonzero if we can optimize the retrieval of specializations
1165 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1166 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1170 {
1173 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1174 parameter. */
1176 /* The optimized lookup depends on the fact that the
1177 template arguments for the member function template apply
1178 purely to the containing class, which is not true if the
1179 containing class is an explicit or partial
1180 specialization. */
1184 /* It is possible to have a template that is not a member
1185 template and is not a member of a template class:
1187 template <typename T>
1188 struct S { friend A::f(); };
1190 Here, the friend function is a template, but the context does
1191 not have template information. The optimized lookup relies
1192 on having ARGS be the template arguments for both the class
1193 and the function template. */
1195 }
1197 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1198 gone through coerce_template_parms by now. */
1200 static void
1202 {
1204 {
1213 /* Allow typedefs on the type of a non-type argument, since a
1215 else
1217 }
1218 }
1220 static void
1222 {
1227 }
1229 /* Retrieve the specialization (in the sense of [temp.spec] - a
1230 specialization is either an instantiation or an explicit
1231 specialization) of TMPL for the given template ARGS. If there is
1232 no such specialization, return NULL_TREE. The ARGS are a vector of
1233 arguments, or a vector of vectors of arguments, in the case of
1234 templates with more than one level of parameters.
1236 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1237 then we search for a partial specialization matching ARGS. This
1238 parameter is ignored if TMPL is not a class template.
1240 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1241 result is a NONTYPE_ARGUMENT_PACK. */
1243 static tree
1245 {
1255 /* There should be as many levels of arguments as there are
1256 levels of parameters. */
1265 /* Lambda functions in templates aren't instantiated normally, but through
1266 tsubst_lambda_expr. */
1271 {
1272 /* The template arguments actually apply to the containing
1273 class. Find the class specialization with those
1274 arguments. */
1276 tree class_specialization
1281 /* Find the instance of TMPL. */
1284 {
1288 /* using-declarations can bring in a different
1289 instantiation of tmpl as a member of a different
1290 instantiation of tmpl's class. We don't want those
1291 here. */
1294 }
1296 }
1297 else
1298 {
1300 spec_entry elt;
1309 else
1317 }
1320 }
1322 /* Like retrieve_specialization, but for local declarations. */
1324 tree
1326 {
1332 }
1334 /* Returns nonzero iff DECL is a specialization of TMPL. */
1336 int
1338 {
1339 tree t;
1342 {
1348 }
1349 else
1350 {
1359 }
1362 }
1364 /* Returns nonzero iff DECL is a specialization of friend declaration
1365 FRIEND_DECL according to [temp.friend]. */
1367 bool
1369 {
1376 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1377 of a template class, we want to check if DECL is a specialization
1378 if this. */
1382 {
1383 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1386 }
1391 /* There is nothing to do if this is not a template friend. */
1398 /* [temp.friend/6]
1399 A member of a class template may be declared to be a friend of a
1400 non-template class. In this case, the corresponding member of
1401 every specialization of the class template is a friend of the
1402 class granting friendship.
1404 For example, given a template friend declaration
1406 template <class T> friend void A<T>::f();
1408 the member function below is considered a friend
1410 template <> struct A<int> {
1411 void f();
1412 };
1414 For this type of template friend, TEMPLATE_DEPTH below will be
1415 nonzero. To determine if DECL is a friend of FRIEND, we first
1416 check if the enclosing class is a specialization of another. */
1423 {
1424 /* Next, we check the members themselves. In order to handle
1425 a few tricky cases, such as when FRIEND_DECL's are
1427 template <class T> friend void A<T>::g(T t);
1428 template <class T> template <T t> friend void A<T>::h();
1430 and DECL's are
1432 void A<int>::g(int);
1433 template <int> void A<int>::h();
1435 we need to figure out ARGS, the template arguments from
1436 the context of DECL. This is required for template substitution
1437 of `T' in the function parameter of `g' and template parameter
1438 of `h' in the above examples. Here ARGS corresponds to `int'. */
1445 {
1447 {
1450 else
1452 current_depth++;
1453 }
1455 }
1458 {
1460 tree friend_type;
1461 tree decl_type;
1462 tree friend_args_type;
1463 tree decl_args_type;
1465 /* Make sure that both DECL and FRIEND_DECL are templates or
1466 non-templates. */
1472 {
1473 /* If both are templates, check template parameter list. */
1474 tree friend_parms
1479 friend_parms))
1483 }
1484 else
1492 /* Check if return types match. */
1496 /* Check if function parameter types match, ignoring the
1497 `this' parameter. */
1506 }
1507 else
1508 {
1509 /* DECL is a TYPE_DECL */
1513 /* Make sure that both DECL and FRIEND_DECL are templates or
1514 non-templates. */
1515 is_template
1522 {
1523 tree friend_parms;
1524 /* If both are templates, check the name of the two
1525 TEMPLATE_DECL's first because is_friend didn't. */
1530 /* Now check template parameter list. */
1531 friend_parms
1534 return comp_template_parms
1536 friend_parms);
1537 }
1538 else
1541 }
1542 }
1544 }
1546 /* Register the specialization SPEC as a specialization of TMPL with
1547 the indicated ARGS. IS_FRIEND indicates whether the specialization
1548 is actually just a friend declaration. ATTRLIST is the list of
1549 attributes that the specialization is declared with or NULL when
1550 it isn't. Returns SPEC, or an equivalent prior declaration, if
1551 available.
1553 We also store instantiations of field packs in the hash table, even
1554 though they are not themselves templates, to make lookup easier. */
1556 static tree
1558 hashval_t hash)
1559 {
1560 tree fn;
1562 spec_entry elt;
1570 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1571 register it; we want the corresponding TEMPLATE_DECL instead.
1572 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1573 the more obvious `uses_template_parms (spec)' to avoid problems
1574 with default function arguments. In particular, given
1575 something like this:
1577 template <class T> void f(T t1, T t = T())
1579 the default argument expression is not substituted for in an
1580 instantiation unless and until it is actually needed. */
1584 /* We don't put these specializations in the hash table, but we might
1585 want to give an error about a mismatch. */
1587 else
1588 {
1599 else
1601 }
1603 /* We can sometimes try to re-register a specialization that we've
1604 already got. In particular, regenerate_decl_from_template calls
1605 duplicate_decls which will update the specialization list. But,
1606 we'll still get called again here anyhow. It's more convenient
1607 to simply allow this than to try to prevent it. */
1611 {
1613 {
1616 {
1618 fn);
1620 }
1621 else
1622 {
1623 tree clone;
1624 /* This situation should occur only if the first
1625 specialization is an implicit instantiation, the
1626 second is an explicit specialization, and the
1627 implicit instantiation has not yet been used. That
1628 situation can occur if we have implicitly
1629 instantiated a member function and then specialized
1630 it later.
1632 We can also wind up here if a friend declaration that
1633 looked like an instantiation turns out to be a
1634 specialization:
1636 template <class T> void foo(T);
1637 class S { friend void foo<>(int) };
1638 template <> void foo(int);
1640 We transform the existing DECL in place so that any
1641 pointers to it become pointers to the updated
1642 declaration.
1644 If there was a definition for the template, but not
1645 for the specialization, we want this to look as if
1646 there were no definition, and vice versa. */
1649 /* The call to duplicate_decls will have applied
1650 [temp.expl.spec]:
1652 An explicit specialization of a function template
1653 is inline only if it is explicitly declared to be,
1654 and independently of whether its function template
1655 is.
1657 to the primary function; now copy the inline bits to
1658 the various clones. */
1660 {
1667 }
1671 }
1672 }
1674 {
1677 /* We've already complained in duplicate_decls. */
1681 /* Dup decl failed, but this is a new definition. Set the
1682 line number so any errors match this new
1683 definition. */
1687 }
1688 }
1692 /* A specialization must be declared in the same namespace as the
1693 template it is specializing. */
1699 {
1708 /* If TMPL is a forward declaration of a template function, keep a list
1709 of all specializations in case we need to reassign them to a friend
1710 template later in tsubst_friend_function.
1712 Also keep a list of all variable template instantiations so that
1713 process_partial_specialization can check whether a later partial
1714 specialization would have used it. */
1717 }
1720 }
1722 /* Restricts tree and type comparisons. */
1726 /* Returns true iff two spec_entry nodes are equivalent. */
1728 bool
1730 {
1739 /* tmpl could be a FIELD_DECL for a capture pack. */
1743 {
1744 /* Partial specializations of a variable template can be distinguished by
1745 constraints. */
1749 }
1755 }
1757 /* Returns a hash for a template TMPL and template arguments ARGS. */
1759 static hashval_t
1761 {
1764 }
1766 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1767 ignoring SPEC. */
1769 hashval_t
1771 {
1773 }
1775 /* Recursively calculate a hash value for a template argument ARG, for use
1776 in the hash tables of template specializations. We must be
1777 careful to (at least) skip the same entities template_args_equal
1778 does. */
1780 hashval_t
1782 {
1787 /* Strip nop-like things, but not the same as STRIP_NOPS. */
1798 {
1833 {
1838 {
1841 }
1843 }
1847 {
1850 }
1861 val = iterative_hash_template_arg
1873 val);
1875 val);
1884 /* [temp.over.link] Two lambda-expressions are never considered
1885 equivalent.
1887 So just hash the closure type. */
1898 /* Now hash operands as usual. */
1902 {
1905 {
1909 }
1911 call_expr_arg_iterator ai;
1916 }
1920 }
1924 {
1927 {
1928 // We want an alias specialization that survived strip_typedefs
1929 // to hash differently from its TYPE_CANONICAL, to avoid hash
1930 // collisions that compare as different in template_args_equal.
1931 // These could be dependent specializations that strip_typedefs
1932 // left alone, or untouched specializations because
1933 // coerce_template_parms returns the unconverted template
1934 // arguments if it sees incomplete argument packs.
1937 }
1940 {
1942 {
1945 /* Do not recurse with TPI directly, as that is unbounded
1946 recursion. */
1949 }
1960 }
1973 }
1977 }
1979 /* Unregister the specialization SPEC as a specialization of TMPL.
1980 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1981 if the SPEC was listed as a specialization of TMPL.
1983 Note that SPEC has been ggc_freed, so we can't look inside it. */
1985 bool
1987 {
1989 spec_entry elt;
1997 {
2002 }
2005 }
2007 /* Like register_specialization, but for local declarations. We are
2008 registering SPEC, an instantiation of TMPL. */
2010 void
2012 {
2015 }
2017 /* TYPE is a class type. Returns true if TYPE is an explicitly
2018 specialized class. */
2020 bool
2022 {
2026 }
2028 /* Print the list of functions at FNS, going through all the overloads
2029 for each element of the list. Alternatively, FNS cannot be a
2030 TREE_LIST, in which case it will be printed together with all the
2031 overloads.
2033 MORE and *STR should respectively be FALSE and NULL when the function
2034 is called from the outside. They are used internally on recursive
2035 calls. print_candidates manages the two parameters and leaves NULL
2036 in *STR when it ends. */
2038 static void
2040 {
2044 else
2046 {
2052 {
2055 else
2058 }
2060 }
2061 }
2063 /* Print the list of candidate FNS in an error message. FNS can also
2064 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
2066 void
2068 {
2072 }
2074 /* Get a (possibly) constrained template declaration for the
2075 purpose of ordering candidates. */
2076 static tree
2078 {
2084 }
2086 /* Among candidates having the same signature, return the
2087 most constrained or NULL_TREE if there is no best candidate.
2088 If the signatures of candidates vary (e.g., template
2089 specialization vs. member function), then there can be no
2090 most constrained.
2092 Note that we don't compare constraints on the functions
2093 themselves, but rather those of their templates. */
2094 static tree
2096 {
2097 // Try to find the best candidate in a first pass.
2100 {
2107 }
2109 // Verify that the champ is better than previous candidates.
2114 }
2117 }
2120 /* Returns the template (one of the functions given by TEMPLATE_ID)
2121 which can be specialized to match the indicated DECL with the
2122 explicit template args given in TEMPLATE_ID. The DECL may be
2123 NULL_TREE if none is available. In that case, the functions in
2124 TEMPLATE_ID are non-members.
2126 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2127 specialization of a member template.
2129 The TEMPLATE_COUNT is the number of references to qualifying
2130 template classes that appeared in the name of the function. See
2131 check_explicit_specialization for a more accurate description.
2133 TSK indicates what kind of template declaration (if any) is being
2134 declared. TSK_TEMPLATE indicates that the declaration given by
2135 DECL, though a FUNCTION_DECL, has template parameters, and is
2136 therefore a template function.
2138 The template args (those explicitly specified and those deduced)
2139 are output in a newly created vector *TARGS_OUT.
2141 If it is impossible to determine the result, an error message is
2142 issued. The error_mark_node is returned to indicate failure. */
2144 static tree
2146 tree decl,
2150 tmpl_spec_kind tsk)
2151 {
2152 tree fns;
2153 tree targs;
2154 tree explicit_targs;
2157 /* A TREE_LIST of templates of which DECL may be a specialization.
2158 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2159 corresponding TREE_PURPOSE is the set of template arguments that,
2160 when used to instantiate the template, would produce a function
2161 with the signature of DECL. */
2171 /* We shouldn't be specializing a member template of an
2172 unspecialized class template; we already gave an error in
2173 check_specialization_scope, now avoid crashing. */
2177 {
2180 }
2188 /* Check for baselinks. */
2193 {
2197 }
2199 {
2202 }
2204 /* Count the number of template headers specified for this
2205 specialization. */
2216 {
2219 tf_warning_or_error,
2223 }
2225 {
2229 {
2230 tree decl_arg_types;
2231 tree fn_arg_types;
2232 tree insttype;
2234 /* In case of explicit specialization, we need to check if
2235 the number of template headers appearing in the specialization
2236 is correct. This is usually done in check_explicit_specialization,
2237 but the check done there cannot be exhaustive when specializing
2238 member functions. Consider the following code:
2240 template <> void A<int>::f(int);
2241 template <> template <> void A<int>::f(int);
2243 Assuming that A<int> is not itself an explicit specialization
2244 already, the first line specializes "f" which is a non-template
2245 member function, whilst the second line specializes "f" which
2246 is a template member function. So both lines are syntactically
2247 correct, and check_explicit_specialization does not reject
2248 them.
2250 Here, we can do better, as we are matching the specialization
2251 against the declarations. We count the number of template
2252 headers, and we check if they match TEMPLATE_COUNT + 1
2253 (TEMPLATE_COUNT is the number of qualifying template classes,
2254 plus there must be another header for the member template
2255 itself).
2257 Notice that if header_count is zero, this is not a
2258 specialization but rather a template instantiation, so there
2259 is no check we can perform here. */
2261 {
2264 }
2266 /* Check that the number of template arguments at the
2267 innermost level for DECL is the same as for FN. */
2275 /* DECL might be a specialization of FN. */
2279 /* For a non-static member function, we need to make sure
2280 that the const qualification is the same. Since
2281 get_bindings does not try to merge the "this" parameter,
2282 we must do the comparison explicitly. */
2284 {
2289 /* And the ref-qualification. */
2293 }
2295 /* Skip the "this" parameter and, for constructors of
2296 classes with virtual bases, the VTT parameter. A
2297 full specialization of a constructor will have a VTT
2298 parameter, but a template never will. */
2299 decl_arg_types
2301 fn_arg_types
2304 /* Function templates cannot be specializations; there are
2305 no partial specializations of functions. Therefore, if
2306 the type of DECL does not match FN, there is no
2307 match.
2309 Note that it should never be the case that we have both
2310 candidates added here, and for regular member functions
2311 below. */
2313 {
2315 current_template_parms))
2328 {
2334 }
2338 }
2340 /* See whether this function might be a specialization of this
2341 template. Suppress access control because we might be trying
2342 to make this specialization a friend, and we have already done
2343 access control for the declaration of the specialization. */
2349 /* We cannot deduce template arguments that when used to
2350 specialize TMPL will produce DECL. */
2354 /* We deduced something involving 'auto', which isn't a valid
2355 template argument. */
2358 /* Remove, from the set of candidates, all those functions
2359 whose constraints are not satisfied. */
2363 // Then, try to form the new function type.
2367 fn_arg_types
2372 /* Save this template, and the arguments deduced. */
2374 }
2376 /* FN is an ordinary member function, and we need a
2377 specialization of a member template. */
2378 ;
2380 /* We can get IDENTIFIER_NODEs here in certain erroneous
2381 cases. */
2382 ;
2384 /* This is just an ordinary non-member function. Nothing can
2385 be a specialization of that. */
2386 ;
2388 /* Cannot specialize functions that are created implicitly. */
2389 ;
2390 else
2391 {
2392 tree decl_arg_types;
2394 /* This is an ordinary member function. However, since
2395 we're here, we can assume its enclosing class is a
2396 template class. For example,
2398 template <typename T> struct S { void f(); };
2399 template <> void S<int>::f() {}
2401 Here, S<int>::f is a non-template, but S<int> is a
2402 template class. If FN has the same type as DECL, we
2403 might be in business. */
2406 /* Its enclosing class is an explicit specialization
2407 of a template class. This is not a candidate. */
2412 /* The return types differ. */
2415 /* Adjust the type of DECL in case FN is a static member. */
2422 decl_arg_types))
2430 // If the deduced arguments do not satisfy the constraints,
2431 // this is not a candidate.
2435 // Add the candidate.
2437 }
2438 }
2441 {
2442 /* We have:
2444 [temp.expl.spec]
2446 It is possible for a specialization with a given function
2447 signature to be instantiated from more than one function
2448 template. In such cases, explicit specification of the
2449 template arguments must be used to uniquely identify the
2450 function template specialization being specialized.
2452 Note that here, there's no suggestion that we're supposed to
2453 determine which of the candidate templates is most
2454 specialized. However, we, also have:
2456 [temp.func.order]
2458 Partial ordering of overloaded function template
2459 declarations is used in the following contexts to select
2460 the function template to which a function template
2461 specialization refers:
2463 -- when an explicit specialization refers to a function
2464 template.
2466 So, we do use the partial ordering rules, at least for now.
2467 This extension can only serve to make invalid programs valid,
2468 so it's safe. And, there is strong anecdotal evidence that
2469 the committee intended the partial ordering rules to apply;
2470 the EDG front end has that behavior, and John Spicer claims
2471 that the committee simply forgot to delete the wording in
2472 [temp.expl.spec]. */
2475 {
2478 }
2479 }
2481 // Concepts allows multiple declarations of member functions
2482 // with the same signature. Like above, we need to rely on
2483 // on the partial ordering of those candidates to determine which
2484 // is the best.
2486 {
2488 {
2491 }
2492 }
2495 {
2500 "saw %d %<template<>%>, need %d for "
2505 }
2509 {
2515 }
2517 /* We have one, and exactly one, match. */
2519 {
2523 /* Propagate the candidate's constraints to the declaration. */
2527 /* DECL is a re-declaration or partial instantiation of a template
2528 function. */
2531 /* It was a specialization of an ordinary member function in a
2532 template class. */
2534 }
2536 /* It was a specialization of a template. */
2539 {
2544 }
2545 else
2548 }
2550 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2551 but with the default argument values filled in from those in the
2552 TMPL_TYPES. */
2554 static tree
2556 tree tmpl_types)
2557 {
2558 tree new_spec_types;
2566 /* Substitute into the rest of the list. */
2567 new_spec_types =
2571 /* Add the default argument for this parameter. */
2574 new_spec_types);
2575 }
2577 /* DECL is an explicit specialization. Replicate default arguments
2578 from the template it specializes. (That way, code like:
2580 template <class T> void f(T = 3);
2581 template <> void f(double);
2582 void g () { f (); }
2584 works, as required.) An alternative approach would be to look up
2585 the correct default arguments at the call-site, but this approach
2586 is consistent with how implicit instantiations are handled. */
2588 static void
2590 {
2591 tree tmpl;
2592 tree spec_types;
2593 tree tmpl_types;
2594 tree new_spec_types;
2595 tree old_type;
2596 tree new_type;
2597 tree t;
2602 /* See if there's anything we need to do. */
2615 {
2616 /* Remove the this pointer, but remember the object's type for
2617 CV quals. */
2623 {
2624 /* DECL may contain more parameters than TMPL due to the extra
2625 in-charge parameter in constructors and destructors. */
2628 }
2630 {
2633 }
2634 }
2636 /* Compute the merged default arguments. */
2637 new_spec_types =
2640 /* Compute the new FUNCTION_TYPE. */
2642 {
2646 new_spec_types);
2649 /* Put the in-charge parameter back. */
2652 new_spec_types);
2656 new_spec_types);
2657 }
2658 else
2660 new_spec_types);
2666 }
2668 /* Return the number of template headers we expect to see for a definition
2669 or specialization of CTYPE or one of its non-template members. */
2671 int
2673 {
2677 {
2678 /* You're supposed to have one `template <...>' for every
2679 template class, but you don't need one for a full
2680 specialization. For example:
2682 template <class T> struct S{};
2683 template <> struct S<int> { void f(); };
2684 void S<int>::f () {}
2686 is correct; there shouldn't be a `template <>' for the
2687 definition of `S<int>::f'. */
2689 /* If CTYPE does not have template information of any
2690 kind, then it is not a template, nor is it nested
2691 within a template. */
2699 }
2702 }
2704 /* Do a simple sanity check on the template headers that precede the
2705 variable declaration DECL. */
2707 void
2709 {
2714 {
2717 "variable templates only available with "
2720 // Namespace-scope variable templates should have a template header.
2722 }
2724 {
2725 auto_diagnostic_group d;
2727 "too many template headers for %qD "
2733 "members of an explicitly specialized class are defined "
2735 }
2736 }
2738 /* An explicit specialization whose declarator-id or class-head-name is not
2739 qualified shall be declared in the nearest enclosing namespace of the
2740 template, or, if the namespace is inline (7.3.1), any namespace from its
2741 enclosing namespace set.
2743 If the name declared in the explicit instantiation is an unqualified name,
2744 the explicit instantiation shall appear in the namespace where its template
2745 is declared or, if that namespace is inline (7.3.1), any namespace from its
2746 enclosing namespace set. */
2748 void
2750 {
2755 {
2761 /* This was allowed in C++98, so only pedwarn. */
2763 "outside its namespace must use a nested-name-"
2765 }
2766 }
2768 /* Warn for a template specialization SPEC that is missing some of a set
2769 of function or type attributes that the template TEMPL is declared with.
2770 ATTRLIST is a list of additional attributes that SPEC should be taken
2771 to ultimately be declared with. */
2773 static void
2775 {
2779 /* Avoid warning if the difference between the primary and
2780 the specialization is not in one of the attributes below. */
2784 };
2786 /* Put together a list of the black listed attributes that the primary
2787 template is declared with that the specialization is not, in case
2788 it's not apparent from the most recent declaration of the primary. */
2789 pretty_printer str;
2796 auto_diagnostic_group d;
2799 spec))
2805 }
2807 /* Check to see if the function just declared, as indicated in
2808 DECLARATOR, and in DECL, is a specialization of a function
2809 template. We may also discover that the declaration is an explicit
2810 instantiation at this point.
2812 Returns DECL, or an equivalent declaration that should be used
2813 instead if all goes well. Issues an error message if something is
2814 amiss. Returns error_mark_node if the error is not easily
2815 recoverable.
2817 FLAGS is a bitmask consisting of the following flags:
2819 2: The function has a definition.
2820 4: The function is a friend.
2822 The TEMPLATE_COUNT is the number of references to qualifying
2823 template classes that appeared in the name of the function. For
2824 example, in
2826 template <class T> struct S { void f(); };
2827 void S<int>::f();
2829 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2830 classes are not counted in the TEMPLATE_COUNT, so that in
2832 template <class T> struct S {};
2833 template <> struct S<int> { void f(); }
2834 template <> void S<int>::f();
2836 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2837 invalid; there should be no template <>.)
2839 If the function is a specialization, it is marked as such via
2840 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2841 is set up correctly, and it is added to the list of specializations
2842 for that template. */
2844 tree
2846 tree decl,
2849 tree attrlist)
2850 {
2859 tmpl_spec_kind tsk;
2862 {
2865 else
2867 }
2868 else
2872 {
2875 {
2878 }
2880 {
2882 /* This could be something like:
2884 template <class T> void f(T);
2885 class S { friend void f<>(int); } */
2887 else
2888 {
2889 /* This case handles bogus declarations like template <>
2890 template <class T> void f<int>(); */
2894 declarator);
2896 }
2897 }
2901 /* The error has already been reported in
2902 check_specialization_scope. */
2908 /* Fall through. */
2921 decl);
2924 else
2928 /* Fall through. */
2934 /* In cases like template<> constexpr bool v = true;
2935 We'll give an error in check_template_variable. */
2941 else
2947 {
2948 /* This case handles bogus declarations like template <>
2949 template <class T> void f<int>(); */
2954 declarator);
2956 {
2957 /* Partial specialization of variable template. */
2961 }
2964 "non-type partial specialization %qE "
2966 else
2968 "non-class, non-variable partial specialization %qE "
2971 ok:;
2972 }
2975 /* This is a specialization of a member template, without
2976 specialization the containing class. Something like:
2978 template <class T> struct S {
2979 template <class U> void f (U);
2980 };
2981 template <> template <class U> void S<int>::f(U) {}
2983 That's a specialization -- but of the entire template. */
2989 }
2992 /* This doesn't apply to variable templates. */
2994 {
2998 {
3002 }
3003 }
3006 {
3012 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
3014 {
3015 tree fns;
3020 else
3021 {
3022 /* If there is no class context, the explicit instantiation
3023 must be at namespace scope. */
3026 /* Find the namespace binding, using the declaration
3027 context. */
3031 {
3032 /* If lookup fails, look for a friend declaration so we can
3033 give a better diagnostic. */
3034 fns = (lookup_qualified_name
3039 }
3042 {
3045 }
3046 }
3049 }
3055 {
3057 /* A specialization in class scope. This is invalid,
3058 but the error will already have been flagged by
3059 check_specialization_scope. */
3061 else
3062 {
3063 /* It's not valid to write an explicit instantiation in
3064 class scope, e.g.:
3066 class C { template void f(); }
3068 This case is caught by the parser. However, on
3069 something like:
3071 template class C { void f(); };
3073 (which is invalid) we can get here. The error will be
3074 issued later. */
3075 ;
3076 }
3079 }
3082 {
3083 // We'll match variable templates in start_decl.
3087 /* Find the list of functions in ctype that have the same
3088 name as the declared function. */
3092 {
3096 {
3097 /* From [temp.expl.spec]:
3099 If such an explicit specialization for the member
3100 of a class template names an implicitly-declared
3101 special member function (clause _special_), the
3102 program is ill-formed.
3104 Similar language is found in [temp.explicit]. */
3107 }
3110 }
3112 /* For a type-conversion operator, We might be looking for
3113 `operator int' which will be a specialization of
3114 `operator T'. Grab all the conversion operators, and
3115 then select from them. */
3120 {
3123 }
3124 else
3126 }
3128 /* Figure out what exactly is being specialized at this point.
3129 Note that for an explicit instantiation, even one for a
3130 member function, we cannot tell a priori whether the
3131 instantiation is for a member template, or just a member
3132 function of a template class. Even if a member template is
3133 being instantiated, the member template arguments may be
3134 elided if they can be deduced from the rest of the
3135 declaration. */
3138 member_specialization,
3139 template_count,
3140 tsk);
3143 /* We couldn't figure out what this declaration was
3144 specializing. */
3146 else
3147 {
3149 {
3150 auto_diagnostic_group d;
3152 "friend declaration %qD is not visible to "
3156 }
3165 {
3166 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3167 is done by do_decl_instantiation later. */
3173 {
3174 /* If TMPL is not the most general template (for
3175 example, if TMPL is a friend template that is
3176 injected into namespace scope), then there will
3177 be too many levels of TARGS. Remove some of them
3178 here. */
3180 tree new_targs;
3187 }
3190 }
3192 /* If we thought that the DECL was a member function, but it
3193 turns out to be specializing a static member function,
3194 make DECL a static member function as well. */
3200 /* If this is a specialization of a member template of a
3201 template class, we want to return the TEMPLATE_DECL, not
3202 the specialization of it. */
3204 {
3209 {
3210 tree parm;
3214 /* We want to use the argument list specified in the
3215 definition, not in the original declaration. */
3220 }
3223 }
3225 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3231 /* Inherit default function arguments from the template
3232 DECL is specializing. */
3236 /* This specialization has the same protection as the
3237 template it specializes. */
3241 /* 7.1.1-1 [dcl.stc]
3243 A storage-class-specifier shall not be specified in an
3244 explicit specialization...
3246 The parser rejects these, so unless action is taken here,
3247 explicit function specializations will always appear with
3248 global linkage.
3250 The action recommended by the C++ CWG in response to C++
3251 defect report 605 is to make the storage class and linkage
3252 of the explicit specialization match the templated function:
3254 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3255 */
3257 {
3261 /* A concept cannot be specialized. */
3263 {
3265 gen_tmpl);
3267 }
3269 /* This specialization has the same linkage and visibility as
3270 the function template it specializes. */
3273 {
3276 }
3279 {
3282 }
3283 }
3285 /* If DECL is a friend declaration, declared using an
3286 unqualified name, the namespace associated with DECL may
3287 have been set incorrectly. For example, in:
3289 template <typename T> void f(T);
3290 namespace N {
3291 struct S { friend void f<int>(int); }
3292 }
3294 we will have set the DECL_CONTEXT for the friend
3295 declaration to N, rather than to the global namespace. */
3300 /* This is not really a declaration of a specialization.
3301 It's just the name of an instantiation. But, it's not
3302 a request for an instantiation, either. */
3305 /* A specialization is not necessarily COMDAT. */
3311 /* If this is a full specialization, register it so that we can find
3312 it again. Partial specializations will be registered in
3313 process_partial_specialization. */
3315 {
3320 }
3323 /* A 'structor should already have clones. */
3329 }
3330 }
3333 }
3335 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3336 parameters. These are represented in the same format used for
3337 DECL_TEMPLATE_PARMS. */
3339 int
3341 {
3342 const_tree p1;
3343 const_tree p2;
3351 {
3363 {
3367 /* If either of the template parameters are invalid, assume
3368 they match for the sake of error recovery. */
3381 }
3382 }
3385 /* One set of parameters has more parameters lists than the
3386 other. */
3390 }
3392 /* Returns true if two template parameters are declared with
3393 equivalent constraints. */
3395 static bool
3397 {
3405 }
3407 /* Returns true when two template parameters are equivalent. */
3409 static bool
3411 {
3415 /* If either of the template parameters are invalid, assume
3416 they match for the sake of error recovery. */
3420 /* ... they declare parameters of the same kind. */
3424 /* ... one parameter was introduced by a parameter declaration, then
3425 both are. This case arises as a result of eagerly rewriting declarations
3426 during parsing. */
3430 /* ... if either declares a pack, they both do. */
3435 {
3436 /* ... if they declare non-type parameters, the types are equivalent. */
3439 }
3441 {
3442 /* ... if they declare template template parameters, their template
3443 parameter lists are equivalent. */
3446 }
3448 /* ... if they are declared with a qualified-concept name, they both
3449 are, and those names are equivalent. */
3451 }
3453 /* Returns true if two template parameters lists are equivalent.
3454 Two template parameter lists are equivalent if they have the
3455 same length and their corresponding parameters are equivalent.
3457 PARMS1 and PARMS2 are TREE_LISTs containing TREE_VECs: the
3458 data structure returned by DECL_TEMPLATE_PARMS.
3460 This is generally the same implementation as comp_template_parms
3461 except that it also the concept names and arguments used to
3462 introduce parameters. */
3464 static bool
3466 {
3473 {
3481 {
3486 }
3490 }
3496 }
3498 /* Return true if the requires-clause of the template parameter lists are
3499 equivalent and false otherwise. */
3500 static bool
3502 {
3510 }
3512 /* Returns true if two template heads are equivalent. 17.6.6.1p6:
3513 Two template heads are equivalent if their template parameter
3514 lists are equivalent and their requires clauses are equivalent.
3516 In pre-C++20, this is equivalent to calling comp_template_parms
3517 for the template parameters of TMPL1 and TMPL2. */
3519 bool
3521 {
3525 /* Don't change the matching rules for pre-C++20. */
3529 /* ... have the same number of template parameters, and their
3530 corresponding parameters are equivalent. */
3534 /* ... if either has a requires-clause, they both do and their
3535 corresponding constraint-expressions are equivalent. */
3537 }
3539 /* Determine whether PARM is a parameter pack. */
3541 bool
3543 {
3544 /* Determine if we have a non-type template parameter pack. */
3551 /* If this is a list of template parameters, we could get a
3552 TYPE_DECL or a TEMPLATE_DECL. */
3556 /* Otherwise it must be a type template parameter. */
3560 }
3562 /* Determine if T is a function parameter pack. */
3564 bool
3566 {
3570 }
3572 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3573 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3575 tree
3577 {
3584 }
3586 /* Return true iff the function parameter PARAM_DECL was expanded
3587 from the function parameter pack PACK. */
3589 bool
3591 {
3596 /* The parameter pack and its pack arguments have the same
3597 DECL_PARM_INDEX. */
3599 }
3601 /* Determine whether ARGS describes a variadic template args list,
3602 i.e., one that is terminated by a template argument pack. */
3604 static bool
3606 {
3608 tree last_parm;
3622 }
3624 /* Generate a new name for the parameter pack name NAME (an
3625 IDENTIFIER_NODE) that incorporates its */
3627 static tree
3629 {
3630 /* Munge the name to include the parameter index. */
3631 #define NUMBUF_LEN 128
3645 }
3647 /* Return true if T is a primary function, class or alias template
3648 specialization, not including the template pattern. */
3650 bool
3652 {
3668 }
3670 /* Return true if PARM is a template template parameter. */
3672 bool
3674 {
3676 }
3678 /* Return true iff PARM is a DECL representing a type template
3679 parameter. */
3681 bool
3683 {
3688 }
3690 /* Return the template parameters of T if T is a
3691 primary template instantiation, NULL otherwise. */
3693 tree
3695 {
3700 parms = INNERMOST_TEMPLATE_PARMS
3704 }
3706 /* Returns the template arguments of T if T is a template instantiation,
3707 NULL otherwise. */
3709 tree
3711 {
3719 }
3721 /* Return the argument pack elements of T if T is a template argument pack,
3722 NULL otherwise. */
3724 tree
3726 {
3732 }
3734 /* In an ARGUMENT_PACK_SELECT, the actual underlying argument that the
3735 ARGUMENT_PACK_SELECT represents. */
3737 static tree
3739 {
3743 /* If the selected argument is an expansion E, that most likely means we were
3744 called from gen_elem_of_pack_expansion_instantiation during the
3745 substituting of an argument pack (of which the Ith element is a pack
3746 expansion, where I is ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
3747 In this case, the Ith element resulting from this substituting is going to
3748 be a pack expansion, which pattern is the pattern of E. Let's return the
3749 pattern of E, and gen_elem_of_pack_expansion_instantiation will build the
3750 resulting pack expansion from it. */
3752 {
3753 /* Make sure we aren't throwing away arg info. */
3756 }
3759 }
3762 /* True iff FN is a function representing a built-in variadic parameter
3763 pack. */
3765 bool
3767 {
3777 }
3779 /* True iff CALL is a call to a function representing a built-in variadic
3780 parameter pack. */
3782 static bool
3784 {
3788 }
3790 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3792 static tree
3794 tree in_decl)
3795 {
3801 {
3803 {
3806 }
3811 }
3812 else
3813 {
3817 /* Calculate the largest value of len that won't make the size of the vec
3818 overflow an int. The compiler will exceed resource limits long before
3819 this, but it seems a decent place to diagnose. */
3823 {
3827 max);
3829 }
3837 }
3838 }
3840 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3841 CALL. */
3843 static tree
3845 tree in_decl)
3846 {
3856 }
3858 /* Structure used to track the progress of find_parameter_packs_r. */
3859 struct find_parameter_pack_data
3860 {
3861 /* TREE_LIST that will contain all of the parameter packs found by
3862 the traversal. */
3865 /* Set of AST nodes that have been visited by the traversal. */
3868 /* True iff we're making a type pack expansion. */
3870 };
3872 /* Identifies all of the argument packs that occur in a template
3873 argument and appends them to the TREE_LIST inside DATA, which is a
3874 find_parameter_pack_data structure. This is a subroutine of
3875 make_pack_expansion and uses_parameter_packs. */
3876 static tree
3878 {
3884 #define WALK_SUBTREE(NODE) \
3885 cp_walk_tree (&(NODE), &find_parameter_packs_r, \
3886 ppd, ppd->visited) \
3888 /* Don't look through typedefs; we are interested in whether a
3889 parameter pack is actually written in the expression/type we're
3890 looking at, not the target type. */
3892 {
3893 /* But do look at arguments for an alias template. */
3900 }
3902 /* Identify whether this is a parameter pack or not. */
3904 {
3912 /* FALLTHRU */
3914 /* If the placeholder appears in the decl-specifier-seq of a function
3915 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3916 is a pack expansion, the invented template parameter is a template
3917 parameter pack. */
3927 {
3928 /* We don't want to walk into the type of a PARM_DECL,
3929 because we don't want to see the type parameter pack. */
3932 }
3937 {
3938 /* We don't want to walk into the type of a variadic capture proxy,
3939 because we don't want to see the type parameter pack. */
3942 }
3944 {
3946 find_parameter_packs_r,
3949 }
3961 /* Not a parameter pack. */
3963 }
3966 {
3967 /* Add this parameter pack to the list. */
3969 }
3975 /* This switch statement will return immediately if we don't find a
3976 parameter pack. ??? Should some of these be in cp_walk_subtrees? */
3978 {
3980 /* Check the template itself. */
3986 {
3988 /* Ignore the declaration of a capture proxy for a parameter pack. */
3992 /* Since we stop at typedefs above, we need to look through them at
3993 the point of the DECL_EXPR. */
3997 }
4024 {
4025 /* Since we defer implicit capture, look in the parms and body. */
4032 }
4035 {
4036 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
4037 type_pack_expansion_p to false so that any placeholders
4038 within the expression don't get marked as parameter packs. */
4046 }
4055 /* Don't walk into IF_STMT_EXTRA_ARGS. */
4062 /* Local class, need to look through the whole definition. */
4066 else
4067 /* Enum, look at the values. */
4081 }
4083 #undef WALK_SUBTREE
4086 }
4088 /* Determines if the expression or type T uses any parameter packs. */
4089 tree
4091 {
4100 }
4102 /* Turn ARG, which may be an expression, type, or a TREE_LIST
4103 representation a base-class initializer into a parameter pack
4104 expansion. If all goes well, the resulting node will be an
4105 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
4106 respectively. */
4107 tree
4109 {
4110 tree result;
4119 {
4120 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
4121 class initializer. In this case, the TREE_PURPOSE will be a
4122 _TYPE node (representing the base class expansion we're
4123 initializing) and the TREE_VALUE will be a TREE_LIST
4124 containing the initialization arguments.
4126 The resulting expansion looks somewhat different from most
4127 expansions. Rather than returning just one _EXPANSION, we
4128 return a TREE_LIST whose TREE_PURPOSE is a
4129 TYPE_PACK_EXPANSION containing the bases that will be
4130 initialized. The TREE_VALUE will be identical to the
4131 original TREE_VALUE, which is a list of arguments that will
4132 be passed to each base. We do not introduce any new pack
4133 expansion nodes into the TREE_VALUE (although it is possible
4134 that some already exist), because the TREE_PURPOSE and
4135 TREE_VALUE all need to be expanded together with the same
4136 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
4137 resulting TREE_PURPOSE will mention the parameter packs in
4138 both the bases and the arguments to the bases. */
4139 tree purpose;
4140 tree value;
4143 /* Determine which parameter packs will be used by the base
4144 class expansion. */
4153 {
4156 arg);
4159 }
4162 {
4163 /* Collect the sets of parameter packs used in each of the
4164 initialization arguments. */
4166 {
4167 /* Determine which parameter packs will be expanded in this
4168 argument. */
4171 }
4172 }
4176 /* Create the pack expansion type for the base type. */
4182 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4183 they will rarely be compared to anything. */
4187 }
4192 /* Build the PACK_EXPANSION_* node. */
4193 result = for_types
4198 {
4199 /* Propagate type and const-expression information. */
4202 /* Mark this read now, since the expansion might be length 0. */
4204 }
4205 else
4206 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4207 they will rarely be compared to anything. */
4210 /* Determine which parameter packs will be expanded. */
4217 /* Make sure we found some parameter packs. */
4219 {
4221 {
4224 else
4226 }
4228 }
4234 }
4236 /* Checks T for any "bare" parameter packs, which have not yet been
4237 expanded, and issues an error if any are found. This operation can
4238 only be done on full expressions or types (e.g., an expression
4239 statement, "if" condition, etc.), because we could have expressions like:
4241 foo(f(g(h(args)))...)
4243 where "args" is a parameter pack. check_for_bare_parameter_packs
4244 should not be called for the subexpressions args, h(args),
4245 g(h(args)), or f(g(h(args))), because we would produce erroneous
4246 error messages.
4248 Returns TRUE and emits an error if there were bare parameter packs,
4249 returns FALSE otherwise. */
4250 bool
4252 {
4268 /* It's OK for a lambda to have an unexpanded parameter pack from the
4269 containing context, but do complain about unexpanded capture packs. */
4274 {
4278 }
4281 {
4286 {
4297 else
4302 else
4306 }
4309 }
4312 }
4314 /* Expand any parameter packs that occur in the template arguments in
4315 ARGS. */
4316 tree
4318 {
4327 /* First, determine if we need to expand anything, and the number of
4328 slots we'll need. */
4330 {
4335 {
4339 else
4341 }
4342 else
4343 {
4345 num_result_args++;
4346 }
4347 }
4349 /* If no expansion is necessary, we're done. */
4353 /* Expand arguments. */
4356 non_default_args_count =
4359 {
4362 {
4369 }
4370 else
4371 {
4374 }
4375 }
4379 }
4381 /* Checks if DECL shadows a template parameter.
4383 [temp.local]: A template-parameter shall not be redeclared within its
4384 scope (including nested scopes).
4386 Emits an error and returns TRUE if the DECL shadows a parameter,
4387 returns FALSE otherwise. */
4389 bool
4391 {
4392 tree olddecl;
4394 /* If we're not in a template, we can't possibly shadow a template
4395 parameter. */
4399 /* Figure out what we're shadowing. */
4403 /* If there's no previous binding for this name, we're not shadowing
4404 anything, let alone a template parameter. */
4408 /* If we're not shadowing a template parameter, we're done. Note
4409 that OLDDECL might be an OVERLOAD (or perhaps even an
4410 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4411 node. */
4415 /* We check for decl != olddecl to avoid bogus errors for using a
4416 name inside a class. We check TPFI to avoid duplicate errors for
4417 inline member templates. */
4423 /* Don't complain about the injected class name, as we've already
4424 complained about the class itself. */
4431 else
4436 }
4438 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4439 ORIG_LEVEL, DECL, and TYPE. */
4441 static tree
4445 tree decl,
4446 tree type)
4447 {
4458 }
4460 /* Find the canonical type parameter for the given template type
4461 parameter. Returns the canonical type parameter, which may be TYPE
4462 if no such parameter existed. */
4464 tree
4466 {
4482 }
4484 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4485 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4486 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4487 new one is created. */
4489 static tree
4491 tsubst_flags_t complain)
4492 {
4497 {
4502 type);
4517 /* Template template parameters need this. */
4520 {
4527 }
4529 /* Attach the TPI to the decl. */
4532 else
4534 }
4537 }
4539 /* Process information from new template parameter PARM and append it
4540 to the LIST being built. This new parameter is a non-type
4541 parameter iff IS_NON_TYPE is true. This new parameter is a
4542 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4543 is in PARM_LOC. */
4545 tree
4548 {
4554 {
4564 }
4571 {
4577 {
4578 /* [temp.param]
4580 The top-level cv-qualifiers on the template-parameter are
4581 ignored when determining its type. */
4586 && !is_parameter_pack
4587 /* If we're in a nested template parameter list, the template
4588 template parameter could be a parameter pack. */
4590 {
4591 /* This template parameter is not a parameter pack, but it
4592 should be. Complain about "bare" parameter packs. */
4595 /* Recover by calling this a parameter pack. */
4597 }
4598 }
4600 /* A template parameter is not modifiable. */
4609 processing_template_decl,
4614 }
4615 else
4616 {
4617 tree t;
4621 {
4623 /* This is for distinguishing between real templates and template
4624 template parameters */
4627 /* any_template_parm_r expects to be able to get the targs of a
4628 DECL_TEMPLATE_RESULT. */
4637 }
4638 else
4639 {
4641 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4644 }
4651 processing_template_decl,
4656 else
4658 }
4662 /* Build requirements for the type/template parameter.
4663 This must be done after SET_DECL_TEMPLATE_PARM_P or
4664 process_template_parm could fail. */
4671 /* Build the parameter node linking the parameter declaration,
4672 its default argument (if any), and its constraints (if any). */
4678 else
4682 }
4684 /* The end of a template parameter list has been reached. Process the
4685 tree list into a parameter vector, converting each parameter into a more
4686 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4687 as PARM_DECLs. */
4689 tree
4691 {
4694 /* Pop the dummy parameter level and add the real one. We do not
4695 morph the dummy parameter in place, as it might have been
4696 captured by a (nested) template-template-parm. */
4699 current_template_parms
4704 {
4710 }
4715 }
4717 // Explicitly indicate the end of the template parameter list. We assume
4718 // that the current template parameters have been constructed and/or
4719 // managed explicitly, as when creating new template template parameters
4720 // from a shorthand constraint.
4721 void
4723 {
4725 }
4727 /* end_template_decl is called after a template declaration is seen. */
4729 void
4731 {
4737 /* This matches the pushlevel in begin_template_parm_list. */
4742 }
4744 /* Takes a TEMPLATE_PARM_P or DECL_TEMPLATE_PARM_P node or a TREE_LIST
4745 thereof, and converts it into an argument suitable to be passed to
4746 the type substitution functions. Note that if the TREE_LIST contains
4747 an error_mark node, the returned argument is error_mark_node. */
4749 tree
4751 {
4762 {
4766 else
4768 }
4774 {
4776 {
4777 /* Turn this argument into a TYPE_ARGUMENT_PACK
4778 with a single element, which expands T. */
4787 }
4788 }
4789 else
4790 {
4792 {
4793 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4794 with a single element, which expands T. */
4804 }
4805 else
4807 }
4809 }
4811 /* Given a single level of template parameters (a TREE_VEC), return it
4812 as a set of template arguments. */
4814 tree
4816 {
4826 }
4828 /* Given a set of template parameters, return them as a set of template
4829 arguments. The template parameters are represented as a TREE_VEC, in
4830 the form documented in cp-tree.h for template arguments. */
4832 tree
4834 {
4835 tree header;
4840 /* If there is only one level of template parameters, we do not
4841 create a TREE_VEC of TREE_VECs. Instead, we return a single
4842 TREE_VEC containing the arguments. */
4847 {
4852 else
4854 }
4857 }
4859 /* Within the declaration of a template, return the currently active
4860 template parameters as an argument TREE_VEC. */
4862 static tree
4864 {
4866 }
4868 /* Return the fully generic arguments for of TMPL, i.e. what
4869 current_template_args would be while parsing it. */
4871 tree
4873 {
4878 /* DECL_TEMPLATE_RESULT doesn't have the arguments we want. For a template
4879 template parameter, it has no TEMPLATE_INFO; for a partial
4880 specialization, it has the arguments for the primary template, and we
4886 }
4888 /* Update the declared TYPE by doing any lookups which were thought to be
4889 dependent, but are not now that we know the SCOPE of the declarator. */
4891 tree
4893 {
4904 /* Don't bother building up the args in this case. */
4906 {
4907 /* tsubst in the args corresponding to the template parameters,
4908 including auto if present. Most things will be unchanged, but
4909 make_typename_type and tsubst_qualified_id will resolve
4910 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4913 tree pushed;
4915 {
4919 }
4924 }
4930 {
4933 else
4935 }
4937 }
4939 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4940 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4941 the new template is a member template. */
4943 static tree
4945 {
4955 /* Propagate module information from the decl. */
4959 }
4961 struct template_parm_data
4962 {
4963 /* The level of the template parameters we are currently
4964 processing. */
4967 /* The index of the specialization argument we are currently
4968 processing. */
4971 /* An array whose size is the number of template parameters. The
4972 elements are nonzero if the parameter has been used in any one
4973 of the arguments processed so far. */
4976 /* An array whose size is the number of template arguments. The
4977 elements are nonzero if the argument makes use of template
4978 parameters of this level. */
4980 };
4982 /* Subroutine of push_template_decl used to see if each template
4983 parameter in a partial specialization is used in the explicit
4984 argument list. If T is of the LEVEL given in DATA (which is
4985 treated as a template_parm_data*), then DATA->PARMS is marked
4986 appropriately. */
4988 static int
4990 {
4998 {
5001 }
5003 /* In C++17 the type of a non-type argument is a deduced context. */
5008 data,
5009 NULL,
5012 /* Return zero so that for_each_template_parm will continue the
5013 traversal of the tree; we want to mark *every* template parm. */
5015 }
5017 /* Process the partial specialization DECL. */
5019 static tree
5021 {
5028 tree inner_parms;
5029 tree inst;
5039 /* A concept cannot be specialized. */
5041 {
5044 }
5049 /* We check that each of the template parameters given in the
5050 partial specialization is used in the argument list to the
5051 specialization. For example:
5053 template <class T> struct S;
5054 template <class T> struct S<T*>;
5056 The second declaration is OK because `T*' uses the template
5057 parameter T, whereas
5059 template <class T> struct S<int>;
5061 is no good. Even trickier is:
5063 template <class T>
5064 struct S1
5065 {
5066 template <class U>
5067 struct S2;
5068 template <class U>
5069 struct S2<T>;
5070 };
5072 The S2<T> declaration is actually invalid; it is a
5073 full-specialization. Of course,
5075 template <class U>
5076 struct S2<T (*)(U)>;
5078 or some such would have been OK. */
5086 {
5091 NULL,
5093 }
5096 {
5097 /* One of the template parms was not used in a deduced context in the
5098 specialization. */
5100 {
5104 }
5108 }
5113 /* [temp.class.spec]
5115 The argument list of the specialization shall not be identical to
5116 the implicit argument list of the primary template. */
5117 tree main_args
5120 && (!flag_concepts
5122 {
5125 "any template arguments; to define the primary template, "
5127 else
5129 "template arguments and is not more constrained than "
5130 "the primary template; to define the primary template, "
5133 }
5135 /* A partial specialization that replaces multiple parameters of the
5136 primary template with a pack expansion is less specialized for those
5137 parameters. */
5139 {
5141 "primary template because it replaces multiple parameters "
5144 /* Avoid crash in process_partial_specialization. */
5146 }
5149 {
5152 /* Avoid crash below. */
5154 }
5156 /* If we aren't in a dependent class, we can actually try deduction. */
5158 /* FIXME we should be able to handle a partial specialization of a
5159 partial instantiation, but currently we can't (c++/41727). */
5162 {
5163 auto_diagnostic_group d;
5167 maintmpl);
5168 }
5170 /* [temp.spec.partial]
5172 The type of a template parameter corresponding to a specialized
5173 non-type argument shall not be dependent on a parameter of the
5174 specialization.
5176 Also, we verify that pack expansions only occur at the
5177 end of the argument list. */
5180 {
5187 {
5188 /* Extract the arguments from the argument pack. We'll be
5189 iterating over these in the following loop. */
5192 }
5195 {
5197 /* Get the Jth argument in the parameter pack. */
5201 {
5202 /* Pack expansions must come at the end of the
5203 argument list. */
5206 {
5210 else
5213 }
5214 }
5217 /* We only care about the pattern. */
5223 /* This next two lines are the `argument expression is not just a
5224 simple identifier' condition and also the `specialized
5225 non-type argument' bit. */
5230 {
5231 /* Look at the corresponding template parameter,
5232 marking which template parameters its type depends
5233 upon. */
5237 {
5238 /* We haven't yet initialized TPD2. Do so now. */
5240 /* The number of parameters here is the number in the
5241 main template, which, as checked in the assertion
5242 above, is NARGS. */
5246 }
5248 /* Mark the template parameters. But this time, we're
5249 looking for the template parameters of the main
5250 template, not in the specialization. */
5257 NULL,
5261 {
5262 /* The type depended on some template parameters.
5263 If they are fully specialized in the
5264 specialization, that's OK. */
5273 "type %qT of template argument %qE depends "
5275 "type %qT of template argument %qE depends "
5277 type,
5278 arg);
5279 }
5280 }
5281 }
5282 }
5284 /* We should only get here once. */
5288 // Build the template decl.
5295 /* Give template template parms a DECL_CONTEXT of the template
5296 for which they are a parameter. */
5298 {
5302 }
5305 /* We didn't register this in check_explicit_specialization so we could
5306 wait until the constraints were set. */
5308 else
5318 {
5324 {
5332 "declaration of %qD ambiguates earlier template "
5336 "partial specialization of %qD after instantiation "
5338 }
5339 }
5342 }
5344 /* PARM is a template parameter of some form; return the corresponding
5345 TEMPLATE_PARM_INDEX. */
5347 static tree
5349 {
5362 }
5364 /* Subroutine of fixed_parameter_pack_p below. Look for any template
5365 parameter packs used by the template parameter PARM. */
5367 static void
5369 {
5370 /* A type parm can't refer to another parm. */
5374 {
5378 }
5384 {
5388 else
5390 }
5391 }
5393 /* PARM is a template parameter pack. Return any parameter packs used in
5394 its type or the type of any of its template parameters. If there are
5395 any such packs, it will be instantiated into a fixed template parameter
5396 list by partial instantiation rather than be fully deduced. */
5398 tree
5400 {
5401 /* This can only be true in a member template. */
5404 /* This can only be true for a parameter pack. */
5407 /* A type parm can't refer to another parm. */
5421 }
5423 /* Check that a template declaration's use of default arguments and
5424 parameter packs is not invalid. Here, PARMS are the template
5425 parameters. IS_PRIMARY is true if DECL is the thing declared by
5426 a primary template. IS_PARTIAL is true if DECL is a partial
5427 specialization.
5429 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
5430 function template declaration or a friend class template
5431 declaration. In the function case, 1 indicates a declaration, 2
5432 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
5433 emitted for extraneous default arguments.
5435 Returns TRUE if there were no errors found, FALSE otherwise. */
5437 bool
5440 {
5443 tree parm_level;
5446 /* [temp.param]
5448 A default template-argument shall not be specified in a
5449 function template declaration or a function template definition, nor
5450 in the template-parameter-list of the definition of a member of a
5451 class template. */
5455 /* You can't have a function template declaration in a local
5456 scope, nor you can you define a member of a class template in a
5457 local scope. */
5465 /* A lambda doesn't have an explicit declaration; don't complain
5466 about the parms of the enclosing class. */
5473 /* If this is either a friend defined in the scope of the class
5474 or a member function. */
5480 /* And, if it was a member function, it really was defined in
5481 the scope of the class. */
5484 /* We already checked these parameters when the template was
5485 declared, so there's no need to do it again now. This function
5486 was defined in class scope, but we're processing its body now
5487 that the class is complete. */
5490 /* Core issue 226 (C++0x only): the following only applies to class
5491 templates. */
5494 {
5495 /* [temp.param]
5497 If a template-parameter has a default template-argument, all
5498 subsequent template-parameters shall have a default
5499 template-argument supplied. */
5501 {
5508 {
5518 {
5520 /* For better subsequent error-recovery, we indicate that
5521 there should have been a default argument. */
5524 }
5526 && !is_friend_decl
5527 /* Don't complain about an enclosing partial
5528 specialization. */
5533 /* A fixed parameter pack will be partially
5534 instantiated into a fixed length list. */
5536 {
5537 /* A primary class template, primary variable template
5538 (DR 2032), or alias template can only have one
5539 parameter pack, at the end of the template
5540 parameter list. */
5548 }
5549 }
5550 }
5551 }
5554 || is_partial
5555 || !is_primary
5557 /* For an ordinary class template, default template arguments are
5558 allowed at the innermost level, e.g.:
5559 template <class T = int>
5560 struct S {};
5561 but, in a partial specialization, they're not allowed even
5562 there, as we have in [temp.class.spec]:
5564 The template parameter list of a specialization shall not
5565 contain default template argument values.
5567 So, for a partial specialization, or for a function template
5568 (in C++98/C++03), we look at all of them. */
5569 ;
5570 else
5571 /* But, for a primary class template that is not a partial
5572 specialization we look at all template parameters except the
5573 innermost ones. */
5576 /* Figure out what error message to issue. */
5591 else
5592 /* Per [temp.param]/9, "A default template-argument shall not be
5593 specified in the template-parameter-lists of the definition of
5594 a member of a class template that appears outside of the member's
5595 class.", thus if we aren't handling a member of a class template
5596 there is no need to examine the parameters. */
5600 /* If we're inside a class definition, there's no need to
5601 examine the parameters to the class itself. On the one
5602 hand, they will be checked when the class is defined, and,
5603 on the other, default arguments are valid in things like:
5604 template <class T = double>
5605 struct S { template <class U> void f(U); };
5606 Here the default argument for `S' has no bearing on the
5607 declaration of `f'. */
5609 else
5610 /* Check everything. */
5616 {
5623 {
5628 {
5630 {
5637 }
5639 /* Clear out the default argument so that we are not
5640 confused later. */
5642 }
5643 }
5645 /* At this point, if we're still interested in issuing messages,
5646 they must apply to classes surrounding the object declared. */
5650 }
5653 }
5655 /* Worker for push_template_decl_real, called via
5656 for_each_template_parm. DATA is really an int, indicating the
5657 level of the parameters we are interested in. If T is a template
5658 parameter of that level, return nonzero. */
5660 static int
5662 {
5668 else
5671 }
5673 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5674 DATA is really an int, indicating the innermost outer level of parameters.
5675 If T is a template parameter of that level or further out, return
5676 nonzero. */
5678 static int
5680 {
5686 else
5689 }
5691 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5692 parameters given by current_template_args, or reuses a
5693 previously existing one, if appropriate. Returns the DECL, or an
5694 equivalent one, if it is replaced via a call to duplicate_decls.
5696 If IS_FRIEND is true, DECL is a friend declaration. */
5698 tree
5700 {
5704 /* See if this is a partial specialization. */
5713 /* No surprising friend functions. */
5718 tree ctx;
5720 /* For a friend, we want the context of the friend, not
5721 the type of which it is a friend. */
5725 /* In the case of a virtual function, we want the class in which
5726 it is defined. */
5728 else
5729 /* Otherwise, if we're currently defining some class, the DECL
5730 is assumed to be a member of the class. */
5739 /* See if this is a primary template. */
5743 /* A friend template that specifies a class context, i.e.
5744 template <typename T> friend void A<T>::f();
5745 is not primary. */
5746 ;
5748 /* Lambdas are not primary. */
5749 ;
5750 else
5753 /* True if the template is a member template, in the sense of
5754 [temp.mem]. */
5758 {
5766 {
5769 }
5771 {
5773 {
5776 }
5778 {
5779 /* [temp.mem]
5781 A destructor shall not be a member template. */
5785 }
5792 {
5793 /* [basic.stc.dynamic.allocation]
5795 An allocation function can be a function
5796 template. ... Template allocation functions shall
5797 have two or more parameters. */
5800 }
5801 }
5807 /* alias-declaration */
5813 else
5814 {
5817 }
5818 }
5825 /* Check to see that the rules regarding the use of default
5826 arguments are not being violated. We check args for a friend
5827 functions when we know whether it's a definition, introducing
5828 declaration or re-declaration. */
5833 /* Ensure that there are no parameter packs in the type of this
5834 declaration that have not been expanded. */
5836 {
5837 /* Check each of the arguments individually to see if there are
5838 any bare parameter packs. */
5844 {
5847 {
5848 /* This is a PARM_DECL that contains unexpanded parameter
5849 packs. We have already complained about this in the
5850 check_for_bare_parameter_packs call, so just replace
5851 these types with ERROR_MARK_NODE. */
5854 }
5858 }
5860 /* Check for bare parameter packs in the return type and the
5861 exception specifiers. */
5863 /* Errors were already issued, set return type to int
5864 as the frontend doesn't expect error_mark_node as
5865 the return type. */
5869 }
5873 {
5876 }
5885 {
5886 /* Does not get a template head. */
5889 }
5896 {
5901 /* If DECL is a TYPE_DECL for a class-template, then there won't
5902 be DECL_LANG_SPECIFIC. The information equivalent to
5903 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5907 {
5908 /* Since a template declaration already existed for this
5909 class-type, we must be redeclaring it here. Make sure
5910 that the redeclaration is valid. */
5912 current_template_parms,
5914 /* We don't need to create a new TEMPLATE_DECL; just use the
5915 one we already had. */
5917 }
5918 else
5919 {
5921 member_template_p);
5926 {
5927 /* A specialization of a member template of a template
5928 class. */
5932 }
5933 }
5934 }
5935 else
5936 {
5942 {
5945 }
5953 {
5954 /* The declaration is a specialization of a member
5955 template, declared outside the class. Therefore, the
5956 innermost template arguments will be NULL, so we
5957 replace them with the arguments determined by the
5958 earlier call to check_explicit_specialization. */
5961 tree new_tmpl
5963 member_template_p);
5971 args,
5974 }
5976 /* Make sure the template headers we got make sense. */
5981 {
5986 }
5987 else
5989 {
5994 {
5998 else
6002 /* Avoid crash in import_export_decl. */
6005 }
6010 /* Can happen in erroneous input. */
6012 else
6014 }
6016 /* Check that the parms are used in the appropriate qualifying scopes
6017 in the declarator. */
6021 {
6027 /* Avoid crash in import_export_decl. */
6030 }
6031 }
6036 {
6037 /* Push template declarations for global functions and types.
6038 Note that we do not try to push a global template friend
6039 declared in a template class; such a thing may well depend on
6040 the template parameters of the class and we'll push it when
6041 instantiating the befriending class. */
6044 {
6049 /* pushdecl may have found an existing template. */
6051 {
6054 }
6055 }
6057 {
6058 /* Record this decl as belonging to the current class. It's
6059 not chained onto anything else. */
6063 }
6064 }
6066 /* The type may have been completed, or (erroneously) changed. */
6070 {
6072 {
6077 /* Give template template parms a DECL_CONTEXT of the template
6078 for which they are a parameter. */
6081 {
6085 }
6089 {
6092 {
6093 /* ??? Why don't we do this here for all templates? */
6096 }
6099 }
6100 }
6102 /* The DECL_TI_ARGS of DECL contains full set of arguments
6103 referring wback to its most general template. If TMPL is a
6104 specialization, ARGS may only have the innermost set of
6105 arguments. Add the missing argument levels if necessary. */
6113 else
6114 {
6117 }
6118 }
6121 && !is_friend
6124 /* Set DECL_COMDAT on template instantiations; if we force
6125 them to be emitted by explicit instantiation,
6126 mark_needed will tell cgraph to do the right thing. */
6132 }
6134 /* FN is an inheriting constructor that inherits from the constructor
6135 template INHERITED; turn FN into a constructor template with a matching
6136 template header. */
6138 tree
6140 {
6141 tree inner_parms
6144 tree parms
6153 }
6155 /* Called when a class template TYPE is redeclared with the indicated
6156 template PARMS, e.g.:
6158 template <class T> struct S;
6159 template <class T> struct S {}; */
6161 bool
6163 {
6164 tree tmpl;
6165 tree tmpl_parms;
6169 {
6172 }
6176 /* The type is nested in some template class. Nothing to worry
6177 about here; there are no new template parameters for the nested
6178 type. */
6182 {
6184 tmpl);
6186 }
6192 {
6202 }
6205 {
6206 tree tmpl_parm;
6207 tree parm;
6208 tree tmpl_default;
6209 tree parm_default;
6223 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
6224 TEMPLATE_DECL. */
6234 {
6235 auto_diagnostic_group d;
6239 }
6241 /* The parameters can be declared to introduce different
6242 constraints. */
6246 {
6247 auto_diagnostic_group d;
6253 }
6256 {
6257 /* We have in [temp.param]:
6259 A template-parameter may not be given default arguments
6260 by two different declarations in the same scope. */
6261 auto_diagnostic_group d;
6266 }
6269 /* Update the previous template parameters (which are the ones
6270 that will really count) with the new default value. */
6273 /* Update the new parameters, too; they'll be used as the
6274 parameters for any members. */
6277 /* Give each template template parm in this redeclaration a
6278 DECL_CONTEXT of the template for which they are a parameter. */
6280 {
6283 }
6284 }
6290 /* Two classes with different constraints declare different entities. */
6292 {
6293 auto_diagnostic_group d;
6299 }
6302 }
6304 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
6305 to be used when the caller has already checked
6306 (processing_template_decl
6307 && !instantiation_dependent_expression_p (expr)
6308 && potential_constant_expression (expr))
6309 and cleared processing_template_decl. */
6311 tree
6313 {
6316 complain,
6320 }
6322 /* Simplify EXPR if it is a non-dependent expression. Returns the
6323 (possibly simplified) expression. */
6325 tree
6327 {
6331 /* If we're in a template, but EXPR isn't value dependent, simplify
6332 it. We're supposed to treat:
6334 template <typename T> void f(T[1 + 1]);
6335 template <typename T> void f(T[2]);
6337 as two declarations of the same function, for example. */
6340 {
6341 processing_template_decl_sentinel s;
6343 }
6345 }
6347 tree
6349 {
6351 }
6353 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
6354 an uninstantiated expression. */
6356 tree
6358 {
6362 {
6365 else
6366 {
6367 processing_template_decl_sentinel s;
6369 }
6370 }
6372 }
6374 /* True iff T is a specialization of a variable template. */
6376 bool
6378 {
6383 }
6385 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
6386 template declaration, or a TYPE_DECL for an alias declaration. */
6388 bool
6390 {
6398 }
6400 /* If T is a specialization of an alias template, return it; otherwise return
6401 NULL_TREE. If TRANSPARENT_TYPEDEFS is true, look through other aliases. */
6403 tree
6406 {
6410 /* It's an alias template specialization if it's an alias and its
6411 TYPE_NAME is a specialization of a primary template. */
6413 {
6420 transparent_typedefs);
6421 }
6424 }
6426 /* An alias template is complex from a SFINAE perspective if a template-id
6427 using that alias can be ill-formed when the expansion is not, as with
6428 the void_t template. We determine this by checking whether the
6429 expansion for the alias template uses all its template parameters. */
6431 struct uses_all_template_parms_data
6432 {
6435 };
6437 static int
6439 {
6447 }
6449 /* for_each_template_parm any_fn callback for complex_alias_template_p. */
6451 static int
6453 {
6454 /* An alias template with a pack expansion that expands a pack from the
6455 enclosing class needs to be considered complex, to avoid confusion with
6456 the same pack being used as an argument to the alias's own template
6457 parameter (91966). */
6464 {
6472 }
6474 }
6476 static bool
6478 {
6479 /* A renaming alias isn't complex. */
6483 /* Any other constrained alias is complex. */
6503 }
6505 /* If T is a specialization of a complex alias template with dependent
6506 template-arguments, return it; otherwise return NULL_TREE. If T is a
6507 typedef to such a specialization, return the specialization. */
6509 tree
6511 {
6522 && (any_dependent_template_arguments_p
6527 {
6530 }
6533 }
6535 /* Return the number of innermost template parameters in TMPL. */
6537 static int
6539 {
6542 }
6544 /* Return either TMPL or another template that it is equivalent to under DR
6545 1286: An alias that just changes the name of a template is equivalent to
6546 the other template. */
6548 static tree
6550 {
6553 {
6554 /* Determine if the alias is equivalent to an underlying template. */
6556 /* The underlying type may have been ill-formed. Don't proceed. */
6569 /* Does the alias add cv-quals? */
6577 /* If TMPL adds or changes any constraints, it isn't equivalent. I think
6578 it's appropriate to treat a less-constrained alias as equivalent. */
6582 /* Alias is equivalent. Strip it and repeat. */
6584 }
6587 }
6589 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6590 must be a reference-to-function or a pointer-to-function type, as specified
6591 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6592 and check that the resulting function has external linkage. */
6594 static tree
6596 tsubst_flags_t complain)
6597 {
6600 linkage_kind linkage;
6618 /* [temp.arg.nontype]/1
6620 A template-argument for a non-type, non-template template-parameter
6621 shall be one of:
6622 [...]
6623 -- the address of an object or function with external [C++11: or
6624 internal] linkage. */
6628 {
6630 {
6637 else
6640 }
6642 }
6646 {
6648 {
6654 else
6658 }
6660 }
6662 accept:
6664 {
6667 else
6669 }
6674 }
6676 /* Subroutine of convert_nontype_argument.
6677 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6678 Emit an error otherwise. */
6680 static bool
6682 tsubst_flags_t complain)
6683 {
6699 {
6705 else
6707 }
6709 }
6711 /* Returns TRUE iff the address of OP is value-dependent.
6713 14.6.2.4 [temp.dep.temp]:
6714 A non-integral non-type template-argument is dependent if its type is
6715 dependent or it has either of the following forms
6716 qualified-id
6717 & qualified-id
6718 and contains a nested-name-specifier which specifies a class-name that
6719 names a dependent type.
6721 We generalize this to just say that the address of a member of a
6722 dependent class is value-dependent; the above doesn't cover the
6723 address of a static data member named with an unqualified-id. */
6725 static bool
6727 {
6730 /* We could use get_inner_reference here, but there's no need;
6731 this is only relevant for template non-type arguments, which
6732 can only be expressed as &id-expression. */
6734 {
6738 }
6741 }
6743 /* The next set of functions are used for providing helpful explanatory
6744 diagnostics for failed overload resolution. Their messages should be
6745 indented by two spaces for consistency with the messages in
6746 call.c */
6748 static int
6750 {
6752 }
6754 /* Other failure functions should call this one, to provide a single function
6755 for setting a breakpoint on. */
6757 static int
6759 {
6761 }
6763 static int
6765 {
6770 }
6772 static int
6774 {
6780 }
6782 static int
6784 {
6788 }
6790 static int
6792 {
6795 " template parameter %qD is not a parameter pack, but "
6799 }
6801 static int
6803 {
6806 " template argument %qE does not match "
6810 }
6812 static int
6814 {
6818 }
6820 static int
6822 {
6828 }
6830 static int
6832 {
6834 {
6839 else
6841 " deduced conflicting values for non-type parameter "
6843 }
6845 }
6847 static int
6849 {
6852 " variable-sized array type %qT is not "
6854 arg);
6856 }
6858 static int
6860 {
6864 arg);
6866 }
6868 static int
6870 {
6872 {
6878 else
6883 }
6885 }
6887 static int
6889 {
6891 }
6893 static int
6896 {
6898 }
6900 static int
6903 {
6909 }
6911 static int
6914 {
6917 {
6925 }
6927 }
6929 static int
6931 {
6934 " template parameters of a template template argument are "
6937 }
6939 static int
6941 {
6947 }
6949 static int
6951 {
6956 }
6958 /* True if T is a C++20 template parameter object to store the argument for a
6959 template parameter of class type. */
6961 bool
6963 {
6966 }
6968 /* Subroutine of convert_nontype_argument, to check whether EXPR, as an
6969 argument for TYPE, points to an unsuitable object.
6971 Also adjust the type of the index in C++20 array subobject references. */
6973 static bool
6975 {
6977 {
6978 CASE_CONVERT:
6980 complain);
6984 complain);
6987 {
6992 }
6996 {
7002 {
7006 /* Canonicalize array offsets to ptrdiff_t; how they were
7007 written doesn't matter for subobject identity. */
7010 }
7013 {
7016 "%qE is not a valid template argument of type %qT "
7019 }
7021 {
7024 "%qE is not a valid template argument of type %qT "
7028 }
7031 {
7034 "%qE is not a valid template argument of type %qT "
7037 }
7038 /* C++17: For a non-type template-parameter of reference or pointer
7039 type, the value of the constant expression shall not refer to (or
7040 for a pointer type, shall not be the address of):
7041 * a subobject (4.5),
7042 * a temporary object (15.2),
7043 * a string literal (5.13.5),
7044 * the result of a typeid expression (8.2.8), or
7045 * a predefined __func__ variable (11.4.1). */
7047 {
7050 decl);
7052 }
7054 && !(same_type_ignoring_top_level_qualifiers_p
7057 {
7062 }
7064 {
7068 decl);
7070 }
7071 }
7079 else
7080 {
7082 {
7085 "because %qD is a variable, not the address of "
7088 }
7089 else
7090 {
7096 }
7097 }
7098 }
7101 }
7103 /* The template arguments corresponding to template parameter objects of types
7104 that contain pointers to members. */
7108 /* Return a VAR_DECL for the C++20 template parameter object corresponding to
7109 template argument EXPR. */
7111 static tree
7113 {
7118 {
7123 }
7127 /* This is no longer a compound literal. */
7146 {
7147 /* If EXPR contains any PTRMEM_CST, they will get clobbered by
7148 lower_var_init before we're done mangling. So store the original
7149 value elsewhere. */
7152 }
7157 }
7159 /* Return the actual template argument corresponding to template parameter
7160 object VAR. */
7162 tree
7164 {
7168 }
7170 /* Attempt to convert the non-type template parameter EXPR to the
7171 indicated TYPE. If the conversion is successful, return the
7172 converted value. If the conversion is unsuccessful, return
7173 NULL_TREE if we issued an error message, or error_mark_node if we
7174 did not. We issue error messages for out-and-out bad template
7175 parameters, but not simply because the conversion failed, since we
7176 might be just trying to do argument deduction. Both TYPE and EXPR
7177 must be non-dependent.
7179 The conversion follows the special rules described in
7180 [temp.arg.nontype], and it is much more strict than an implicit
7181 conversion.
7183 This function is called twice for each template argument (see
7184 lookup_template_class for a more accurate description of this
7185 problem). This means that we need to handle expressions which
7186 are not valid in a C++ source, but can be created from the
7187 first call (for instance, casts to perform conversions). These
7188 hacks can go away after we fix the double coercion problem. */
7190 static tree
7192 {
7193 tree expr_type;
7196 /* Detect immediately string literals as invalid non-type argument.
7197 This special-case is not needed for correctness (we would easily
7198 catch this later), but only to provide better diagnostic for this
7199 common user mistake. As suggested by DR 100, we do not mention
7200 linkage issues in the diagnostic as this is not the point. */
7202 {
7208 }
7210 /* Add the ADDR_EXPR now for the benefit of
7211 value_dependent_expression_p. */
7214 {
7218 }
7220 /* If we are in a template, EXPR may be non-dependent, but still
7221 have a syntactic, rather than semantic, form. For example, EXPR
7222 might be a SCOPE_REF, rather than the VAR_DECL to which the
7223 SCOPE_REF refers. Preserving the qualifying scope is necessary
7224 so that access checking can be performed when the template is
7225 instantiated -- but here we need the resolved form so that we can
7226 convert the argument. */
7238 /* If the argument is non-dependent, perform any conversions in
7239 non-dependent context as well. */
7248 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
7249 to a non-type argument of "nullptr". */
7253 /* In C++11, integral or enumeration non-type template arguments can be
7254 arbitrary constant expressions. Pointer and pointer to
7255 member arguments can be general constant expressions that evaluate
7256 to a null value, but otherwise still need to be of a specific form. */
7258 {
7260 /* A PTRMEM_CST is already constant, and a valid template
7261 argument for a parameter of pointer to member type, we just want
7262 to leave it in that form rather than lower it to a
7266 {
7267 /* C++17: A template-argument for a non-type template-parameter shall
7268 be a converted constant expression (8.20) of the type of the
7269 template-parameter. */
7272 /* Make sure we return NULL_TREE only if we have really issued
7273 an error, as described above. */
7276 {
7279 }
7283 }
7285 {
7291 }
7292 }
7296 else
7299 /* HACK: Due to double coercion, we can get a
7300 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
7301 which is the tree that we built on the first call (see
7302 below when coercing to reference to object or to reference to
7303 function). We just strip everything and get to the arg.
7304 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
7305 for examples. */
7307 {
7313 {
7314 /* ??? Maybe we could use convert_from_reference here, but we
7315 would need to relax its constraints because the NOP_EXPR
7316 could actually change the type to something more cv-qualified,
7317 and this is not folded by convert_from_reference. */
7322 && (same_type_ignoring_top_level_qualifiers_p
7325 {
7328 }
7329 }
7330 }
7332 /* [temp.arg.nontype]/5, bullet 1
7334 For a non-type template-parameter of integral or enumeration type,
7335 integral promotions (_conv.prom_) and integral conversions
7336 (_conv.integral_) are applied. */
7339 {
7341 {
7346 }
7351 /* Notice that there are constant expressions like '4 % 0' which
7352 do not fold into integer constants. */
7354 {
7356 {
7360 else
7366 /* else cxx_constant_value complained but gave us
7367 a real constant, so go ahead. */
7369 {
7370 /* Some assemble time constant expressions like
7371 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
7372 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
7373 as we can emit them into .rodata initializers of
7374 variables, yet they can't fold into an INTEGER_CST at
7375 compile time. Refuse them here. */
7380 }
7381 }
7382 else
7384 }
7386 /* Avoid typedef problems. */
7389 }
7390 /* [temp.arg.nontype]/5, bullet 2
7392 For a non-type template-parameter of type pointer to object,
7393 qualification conversions (_conv.qual_) and the array-to-pointer
7394 conversion (_conv.array_) are applied. */
7396 {
7399 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
7400 decay_conversion or an explicit cast. If it's a problematic cast,
7401 we'll complain about it below. */
7403 {
7408 {
7411 }
7412 }
7414 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
7416 A template-argument for a non-type, non-template template-parameter
7417 shall be one of: [...]
7419 -- the name of a non-type template-parameter;
7420 -- the address of an object or function with external linkage, [...]
7421 expressed as "& id-expression" where the & is optional if the name
7422 refers to a function or array, or if the corresponding
7423 template-parameter is a reference.
7425 Here, we do not care about functions, as they are invalid anyway
7426 for a parameter of type pointer-to-object. */
7429 /* Non-type template parameters are OK. */
7430 ;
7435 /* Other values, like integer constants, might be valid
7436 non-type arguments of some other type. */
7446 }
7447 /* [temp.arg.nontype]/5, bullet 3
7449 For a non-type template-parameter of type reference to object, no
7450 conversions apply. The type referred to by the reference may be more
7451 cv-qualified than the (otherwise identical) type of the
7452 template-argument. The template-parameter is bound directly to the
7453 template-argument, which must be an lvalue. */
7455 {
7457 expr_type))
7461 {
7466 }
7469 {
7474 }
7476 /* [temp.arg.nontype]/1
7478 A template-argument for a non-type, non-template template-parameter
7479 shall be one of: [...]
7481 -- the address of an object or function with external linkage. */
7484 {
7487 {
7490 "because a reference variable does not have a constant "
7493 }
7494 }
7497 /* OK, dependent reference. We don't want to ask whether a DECL is
7499 else
7500 {
7505 }
7509 }
7510 /* [temp.arg.nontype]/5, bullet 4
7512 For a non-type template-parameter of type pointer to function, only
7513 the function-to-pointer conversion (_conv.func_) is applied. If the
7514 template-argument represents a set of overloaded functions (or a
7515 pointer to such), the matching function is selected from the set
7516 (_over.over_). */
7518 {
7519 /* If the argument is a template-id, we might not have enough
7520 context information to decay the pointer. */
7522 {
7526 }
7529 /* Null pointer values are OK in C++11. */
7535 }
7536 /* [temp.arg.nontype]/5, bullet 5
7538 For a non-type template-parameter of type reference to function, no
7539 conversions apply. If the template-argument represents a set of
7540 overloaded functions, the matching function is selected from the set
7541 (_over.over_). */
7543 {
7545 {
7547 {
7552 }
7554 }
7559 }
7560 /* [temp.arg.nontype]/5, bullet 6
7562 For a non-type template-parameter of type pointer to member function,
7563 no conversions apply. If the template-argument represents a set of
7564 overloaded member functions, the matching member function is selected
7565 from the set (_over.over_). */
7567 {
7572 /* [temp.arg.nontype] bullet 1 says the pointer to member
7573 expression must be a pointer-to-member constant. */
7578 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
7579 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
7582 }
7583 /* [temp.arg.nontype]/5, bullet 7
7585 For a non-type template-parameter of type pointer to data member,
7586 qualification conversions (_conv.qual_) are applied. */
7588 {
7589 /* [temp.arg.nontype] bullet 1 says the pointer to member
7590 expression must be a pointer-to-member constant. */
7598 }
7600 {
7602 {
7607 }
7609 }
7611 {
7612 /* Replace the argument with a reference to the corresponding template
7613 parameter object. */
7618 }
7619 /* A template non-type parameter must be one of the above. */
7620 else
7623 /* Sanity check: did we actually convert the argument to the
7624 right type? */
7628 }
7630 /* Subroutine of coerce_template_template_parms, which returns 1 if
7631 PARM_PARM and ARG_PARM match using the rule for the template
7632 parameters of template template parameters. Both PARM and ARG are
7633 template parameters; the rest of the arguments are the same as for
7634 coerce_template_template_parms.
7635 */
7636 static int
7638 tree arg,
7639 tsubst_flags_t complain,
7640 tree in_decl,
7641 tree outer_args)
7642 {
7651 {
7653 /* We encounter instantiations of templates like
7654 template <template <template <class> class> class TT>
7655 class C; */
7656 {
7663 }
7664 /* Fall through. */
7669 /* Argument is a parameter pack but parameter is not. */
7674 /* The tsubst call is used to handle cases such as
7676 template <int> class C {};
7677 template <class T, template <T> class TT> class D {};
7678 D<int, C> d;
7680 i.e. the parameter list of TT depends on earlier parameters. */
7682 {
7687 }
7691 /* Argument is a parameter pack but parameter is not. */
7698 }
7701 }
7703 /* Coerce template argument list ARGLIST for use with template
7704 template-parameter TEMPL. */
7706 static tree
7708 tsubst_flags_t complain)
7709 {
7710 /* Consider an example where a template template parameter declared as
7712 template <class T, class U = std::allocator<T> > class TT
7714 The template parameter level of T and U are one level larger than
7715 of TT. To proper process the default argument of U, say when an
7716 instantiation `TT<int>' is seen, we need to build the full
7717 arguments containing {int} as the innermost level. Outer levels,
7718 available when not appearing as default template argument, can be
7719 obtained from the arguments of the enclosing template.
7721 Suppose that TT is later substituted with std::vector. The above
7722 instantiation is `TT<int, std::allocator<T> >' with TT at
7723 level 1, and T at level 2, while the template arguments at level 1
7724 becomes {std::vector} and the inner level 2 is {int}. */
7730 {
7731 /* This is an argument of the current template, so we haven't set
7732 DECL_CONTEXT yet. */
7733 tree relevant_template_parms;
7735 /* Parameter levels that are greater than the level of the given
7736 template template parm are irrelevant. */
7743 }
7750 complain,
7753 }
7755 /* A cache of template template parameters with match-all default
7756 arguments. */
7759 /* T is a bound template template-parameter. Copy its arguments into default
7760 arguments of the template template-parameter's template parameters. */
7762 static tree
7764 {
7787 {
7790 {
7793 }
7794 }
7798 }
7800 /* ARG is a bound potential template template-argument, and PARGS is a list
7801 of arguments for the corresponding template template-parameter. Adjust
7802 PARGS as appropriate for application to ARG's template, and if ARG is a
7803 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7804 arguments to the template template parameter. */
7806 static tree
7808 {
7812 {
7813 /* When comparing two template template-parameters in partial ordering,
7814 rewrite the one currently being used as an argument to have default
7815 arguments for all parameters. */
7821 }
7822 else
7823 {
7824 tree aparms
7829 }
7832 }
7834 /* Subroutine of unify for the case when PARM is a
7835 BOUND_TEMPLATE_TEMPLATE_PARM. */
7837 static int
7840 {
7844 /* The template template parm might be variadic and the argument
7845 not, so flatten both argument lists. */
7850 {
7851 /* In keeping with P0522R0, adjust P's template arguments
7852 to apply to A's template; then flatten it again. */
7860 /* If the P0522 adjustment eliminated a pack expansion, deduce
7861 empty packs. */
7867 }
7868 else
7869 {
7870 /* Deduce arguments T, i from TT<T> or TT<i>.
7871 We check each element of PARMVEC and ARGVEC individually
7872 rather than the whole TREE_VEC since they can have
7873 different number of elements, which is allowed under N2555. */
7877 /* Check if the parameters end in a pack, making them
7878 variadic. */
7885 /* If the template argument list of P contains a pack
7886 expansion that is not the last template argument, the
7887 entire template argument list is a non-deduced
7888 context. */
7906 DEDUCE_EXACT,
7909 }
7912 }
7914 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7915 template template parameters. Both PARM_PARMS and ARG_PARMS are
7916 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7917 or PARM_DECL.
7919 Consider the example:
7920 template <class T> class A;
7921 template<template <class U> class TT> class B;
7923 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7924 the parameters to A, and OUTER_ARGS contains A. */
7926 static int
7928 tree arg_parms,
7929 tsubst_flags_t complain,
7930 tree in_decl,
7931 tree outer_args)
7932 {
7944 {
7945 /* P0522R0: A template template-parameter P is at least as specialized as
7946 a template template-argument A if, given the following rewrite to two
7947 function templates, the function template corresponding to P is at
7948 least as specialized as the function template corresponding to A
7949 according to the partial ordering rules for function templates
7950 ([temp.func.order]). Given an invented class template X with the
7951 template parameter list of A (including default arguments):
7953 * Each of the two function templates has the same template parameters,
7954 respectively, as P or A.
7956 * Each function template has a single function parameter whose type is
7957 a specialization of X with template arguments corresponding to the
7958 template parameters from the respective function template where, for
7959 each template parameter PP in the template parameter list of the
7960 function template, a corresponding template argument AA is formed. If
7961 PP declares a parameter pack, then AA is the pack expansion
7962 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7964 If the rewrite produces an invalid type, then P is not at least as
7965 specialized as A. */
7967 /* So coerce P's args to apply to A's parms, and then deduce between A's
7968 args and the converted args. If that succeeds, A is at least as
7969 specialized as P, so they match.*/
7977 {
7983 }
7984 }
7986 /* Determine whether we have a parameter pack at the end of the
7987 template template parameter's template parameter list. */
7989 {
7996 {
8010 }
8011 }
8017 /* Check all of the template parameters except the parameter pack at
8018 the end (if any). */
8020 {
8029 outer_args))
8032 }
8035 {
8036 /* Check each of the template parameters in the template
8037 argument against the template parameter pack at the end of
8038 the template template parameter. */
8045 {
8052 outer_args))
8054 }
8055 }
8058 }
8060 /* Verifies that the deduced template arguments (in TARGS) for the
8061 template template parameters (in TPARMS) represent valid bindings,
8062 by comparing the template parameter list of each template argument
8063 to the template parameter list of its corresponding template
8064 template parameter, in accordance with DR150. This
8065 routine can only be called after all template arguments have been
8066 deduced. It will return TRUE if all of the template template
8067 parameter bindings are okay, FALSE otherwise. */
8068 bool
8070 {
8074 /* We're dealing with template parms in this process. */
8080 {
8085 {
8090 {
8091 /* Look inside the argument pack. */
8094 }
8097 {
8101 /* Extract the next argument from the argument
8102 pack. */
8106 /* Look at the pattern of the pack expansion. */
8109 /* Extract the template parameters from the template
8110 argument. */
8116 /* Verify that we can coerce the template template
8117 parameters from the template argument to the template
8118 parameter. This requires an exact match. */
8120 && !coerce_template_template_parms
8122 targ_parms,
8123 tf_none,
8124 tparm,
8125 targs))
8126 {
8129 }
8130 }
8131 }
8132 }
8134 out:
8138 }
8140 /* Since type attributes aren't mangled, we need to strip them from
8141 template type arguments. */
8143 tree
8145 {
8155 }
8157 /* And from inside dependent non-type arguments like sizeof(Type). */
8159 static tree
8161 {
8171 }
8173 /* A template declaration can be substituted for a constrained
8174 template template parameter only when the argument is no more
8175 constrained than the parameter. */
8177 static bool
8179 {
8182 /* For now, allow constrained template template arguments
8183 and unconstrained template template parameters. */
8187 /* If the template parameter is constrained, we need to rewrite its
8188 constraints in terms of the ARG's template parameters. This ensures
8189 that all of the template parameter types will have the same depth.
8191 Note that this is only valid when coerce_template_template_parm is
8192 true for the innermost template parameters of PARM and ARG. In other
8193 words, because coercion is successful, this conversion will be valid. */
8196 {
8203 }
8206 }
8208 // Convert a placeholder argument into a binding to the original
8209 // parameter. The original parameter is saved as the TREE_TYPE of
8210 // ARG.
8213 {
8216 }
8218 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
8219 because one of them is dependent. But we need to represent the
8220 conversion for the benefit of cp_tree_equal. */
8222 static tree
8224 {
8225 /* Auto parms get no conversion. */
8228 /* We don't need or want to add this conversion now if we're going to use the
8229 argument for deduction. */
8241 }
8243 /* Convert the indicated template ARG as necessary to match the
8244 indicated template PARM. Returns the converted ARG, or
8245 error_mark_node if the conversion was unsuccessful. Error and
8246 warning messages are issued under control of COMPLAIN. This
8247 conversion is for the Ith parameter in the parameter list. ARGS is
8248 the full set of template arguments deduced so far. */
8250 static tree
8252 tree arg,
8253 tree args,
8254 tsubst_flags_t complain,
8256 tree in_decl)
8257 {
8258 tree orig_arg;
8259 tree val;
8265 /* Trivially convert placeholders. */
8274 {
8275 /* The template argument was the name of some
8276 member function. That's usually
8277 invalid, but static members are OK. In any
8278 case, grab the underlying fields/functions
8279 and issue an error later if required. */
8281 }
8289 /* When determining whether an argument pack expansion is a template,
8290 look at the pattern. */
8294 /* Deal with an injected-class-name used as a template template arg. */
8296 {
8299 {
8309 }
8310 }
8312 is_tmpl_type =
8328 {
8330 {
8334 }
8337 "to refer to a type member of a template parameter, "
8342 typename_type,
8343 complain);
8346 }
8348 {
8350 {
8352 {
8357 {
8358 /* The template argument is a type, but we're expecting
8359 an expression. */
8364 /* [temp.arg]/2: "In a template-argument, an ambiguity
8365 between a type-id and an expression is resolved to a
8366 type-id, regardless of the form of the corresponding
8367 template-parameter." So give the user a clue. */
8370 "for non-type template parameter is treated as "
8372 }
8376 else
8379 }
8380 }
8382 }
8384 {
8386 {
8393 else
8396 }
8398 }
8401 /* We already did the appropriate conversion when packing args. */
8404 {
8406 {
8408 /* The number of argument required is not known yet.
8409 Just accept it for now. */
8411 else
8412 {
8414 tree argparm;
8416 /* Strip alias templates that are equivalent to another
8417 template. */
8423 args))
8424 {
8427 /* TEMPLATE_TEMPLATE_PARM node is preferred over
8428 TEMPLATE_DECL. */
8430 {
8435 }
8436 }
8437 else
8438 {
8440 {
8447 }
8450 }
8452 // Check that the constraints are compatible before allowing the
8453 // substitution.
8456 {
8458 {
8464 }
8466 }
8467 }
8468 }
8469 else
8471 /* We only form one instance of each template specialization.
8472 Therefore, if we use a non-canonical variant (i.e., a
8473 typedef), any future messages referring to the type will use
8474 the typedef, which is confusing if those future uses do not
8475 themselves also use the typedef. */
8478 }
8479 else
8480 {
8485 /* We don't have enough levels of args to do any substitution. This
8488 {
8490 LOOKUP_IMPLICIT);
8493 }
8494 else
8500 /* Drop top-level cv-qualifiers on the substituted/deduced type of
8501 this non-type template parameter, as per [temp.param]/6. */
8509 /* We used to call digest_init here. However, digest_init
8510 will report errors, which we don't want when complain
8511 is zero. More importantly, digest_init will try too
8512 hard to convert things: for example, `0' should not be
8513 converted to pointer type at this point according to
8514 the standard. Accepting this is not merely an
8515 extension, since deciding whether or not these
8516 conversions can occur is part of determining which
8517 function template to call, or whether a given explicit
8518 argument specification is valid. */
8520 else
8521 {
8524 }
8535 {
8536 /* Reject template arguments that are references to built-in
8537 functions with no library fallbacks. */
8546 }
8549 {
8550 /* Strip typedefs from the SCOPE_REF. */
8553 complain);
8556 }
8557 }
8560 }
8562 /* Coerces the remaining template arguments in INNER_ARGS (from
8563 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
8564 Returns the coerced argument pack. PARM_IDX is the position of this
8565 parameter in the template parameter list. ARGS is the original
8566 template argument list. */
8567 static tree
8570 tree args,
8571 tree inner_args,
8573 tree new_args,
8575 tree in_decl,
8576 tsubst_flags_t complain)
8577 {
8580 tree packed_args;
8581 tree argument_pack;
8588 {
8589 /* When the template parameter is a non-type template parameter pack
8590 or template template parameter pack whose type or template
8591 parameters use parameter packs, we know exactly how many arguments
8592 we are looking for. Build a vector of the instantiated decls for
8593 these template parameters in PACKED_PARMS. */
8594 /* We can't use make_pack_expansion here because it would interpret a
8595 _DECL as a use rather than a declaration. */
8609 /* If we're doing a partial instantiation of a member template,
8610 verify that all of the types used for the non-type
8611 template parameter pack are, in fact, valid for non-type
8612 template parameters. */
8615 {
8618 {
8623 }
8624 /* We don't know how many args we have yet, just
8625 use the unconverted ones for now. */
8627 }
8630 }
8631 /* Check if we have a placeholder pack, which indicates we're
8632 in the context of a introduction list. In that case we want
8633 to match this pack to the single placeholder. */
8637 {
8640 }
8641 else
8644 /* Convert the remaining arguments, which will be a part of the
8645 parameter pack "parm". */
8648 {
8654 {
8655 /* Once we've packed as many args as we have types, stop. */
8659 /* We don't know how many args we have yet, just
8660 use the unconverted ones for now. */
8662 else
8664 }
8667 {
8670 }
8671 else
8674 in_decl);
8678 }
8682 {
8687 }
8692 else
8693 {
8696 }
8703 }
8705 /* Returns the number of pack expansions in the template argument vector
8706 ARGS. */
8708 static int
8710 {
8715 {
8719 }
8721 }
8723 /* Convert all template arguments to their appropriate types, and
8724 return a vector containing the innermost resulting template
8725 arguments. If any error occurs, return error_mark_node. Error and
8726 warning messages are issued under control of COMPLAIN.
8728 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8729 for arguments not specified in ARGS. Otherwise, if
8730 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
8731 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
8732 USE_DEFAULT_ARGS is false, then all arguments must be specified in
8733 ARGS. */
8735 static tree
8737 tree args,
8738 tree in_decl,
8739 tsubst_flags_t complain,
8742 {
8744 tree orig_inner_args;
8745 tree inner_args;
8746 tree new_args;
8747 tree new_inner_args;
8749 /* When used as a boolean value, indicates whether this is a
8750 variadic template parameter list. Since it's an int, we can also
8751 subtract it from nparms to get the number of non-variadic
8752 parameters. */
8757 /* Adjustment to nparms for fixed parameter packs. */
8762 /* Likewise for parameters with default arguments. */
8770 /* Determine if there are any parameter packs or default arguments. */
8772 {
8780 }
8783 /* If there are no parameters that follow a parameter pack, we need to
8784 expand any argument packs so that we can deduce a parameter pack from
8785 some non-packed args followed by an argument pack, as in variadic85.C.
8786 If there are such parameters, we need to leave argument packs intact
8787 so the arguments are assigned properly. This can happen when dealing
8788 with a nested class inside a partial specialization of a class
8789 template, as in variadic92.C, or when deducing a template parameter pack
8790 from a sub-declarator, as in variadic114.C. */
8794 /* Count any pack expansion args. */
8800 && require_all_args
8801 && !variadic_args_p
8802 && (!use_default_args
8805 {
8806 bad_nargs:
8808 {
8810 {
8814 }
8815 else
8822 }
8825 }
8826 /* We can't pass a pack expansion to a non-pack parameter of an alias
8827 template (DR 1430). */
8831 && variadic_args_p
8833 {
8835 {
8837 {
8843 {
8846 "pack expansion argument for non-pack parameter "
8848 else
8850 "pack expansion argument for non-pack parameter "
8854 }
8855 }
8857 found:;
8858 }
8860 }
8862 /* We need to evaluate the template arguments, even though this
8863 template-id may be nested within a "sizeof". */
8864 cp_evaluated ev;
8870 {
8871 tree arg;
8872 tree parm;
8874 /* Get the Ith template parameter. */
8878 {
8881 }
8883 /* Calculate the next argument. */
8886 else
8892 {
8893 /* Some arguments will be placed in the
8894 template parameter pack PARM. */
8901 {
8902 /* We don't know how many args we have yet, just use the
8903 unconverted (and still packed) ones for now. */
8907 }
8911 /* Store this argument. */
8913 {
8914 lost++;
8915 /* We are done with all of the arguments. */
8918 }
8919 else
8920 {
8924 {
8927 }
8928 }
8931 }
8933 {
8935 {
8936 /* "If every valid specialization of a variadic template
8937 requires an empty template parameter pack, the template is
8938 ill-formed, no diagnostic required." So check that the
8939 pattern works with this parameter. */
8944 in_decl);
8946 {
8951 }
8953 /* Recover from missing typename. */
8957 /* We don't know how many args we have yet, just
8958 use the unconverted ones for now. */
8962 }
8963 }
8965 {
8966 /* There must be a default arg in this case. */
8969 /* The position of the first default template argument,
8970 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8971 Record that. */
8975 }
8976 else
8980 {
8983 }
8985 {
8986 /* This can occur if there was an error in the template
8987 parameter list itself (which we would already have
8988 reported) that we are trying to recover from, e.g., a class
8989 template with a parameter list such as
8990 template<typename..., typename> (cpp0x/variadic150.C). */
8993 /* This can also happen with a fixed parameter pack (71834). */
8996 }
8997 else
9003 lost++;
9006 }
9009 {
9010 /* If we had fixed parameter packs, we didn't know how many arguments we
9011 actually needed earlier; now we do. */
9015 }
9018 {
9019 /* We had some pack expansion arguments that will only work if the packs
9020 are empty, but wait until instantiation time to complain.
9021 See variadic-ttp3.C. */
9023 /* Except that we can't provide empty packs to alias templates or
9024 concepts when there are no corresponding parameters. Basically,
9025 we can get here with this:
9027 template<typename T> concept C = true;
9029 template<typename... Args>
9030 requires C<Args...>
9031 void f();
9033 When parsing C<Args...>, we try to form a concept check of
9034 C<?, Args...>. Without the extra check for substituting an empty
9035 pack past the last parameter, we can accept the check as valid.
9037 FIXME: This may be valid for alias templates (but I doubt it).
9039 FIXME: The error could be better also. */
9041 {
9046 }
9057 }
9060 {
9063 }
9070 }
9072 /* Convert all template arguments to their appropriate types, and
9073 return a vector containing the innermost resulting template
9074 arguments. If any error occurs, return error_mark_node. Error and
9075 warning messages are not issued.
9077 Note that no function argument deduction is performed, and default
9078 arguments are used to fill in unspecified arguments. */
9079 tree
9081 {
9083 }
9085 /* Convert all template arguments to their appropriate type, and
9086 instantiate default arguments as needed. This returns a vector
9087 containing the innermost resulting template arguments, or
9088 error_mark_node if unsuccessful. */
9089 tree
9091 tsubst_flags_t complain)
9092 {
9094 }
9096 /* Like coerce_template_parms. If PARMS represents all template
9097 parameters levels, this function returns a vector of vectors
9098 representing all the resulting argument levels. Note that in this
9099 case, only the innermost arguments are coerced because the
9100 outermost ones are supposed to have been coerced already.
9102 Otherwise, if PARMS represents only (the innermost) vector of
9103 parameters, this function returns a vector containing just the
9104 innermost resulting arguments. */
9106 static tree
9108 tree args,
9109 tree in_decl,
9110 tsubst_flags_t complain,
9113 {
9116 tree coerced_args;
9119 {
9121 tree level;
9127 {
9128 tree l;
9132 require_all_args,
9133 use_default_args);
9134 else
9141 }
9142 }
9143 else
9146 require_all_args,
9147 use_default_args);
9149 }
9151 /* Returns true if T is a wrapper to make a C++20 template parameter
9152 object const. */
9154 static bool
9156 {
9162 }
9164 /* Returns 1 if template args OT and NT are equivalent. */
9166 int
9168 {
9181 /* DR 1558: Don't treat an alias template specialization with dependent
9182 arguments as equivalent to its underlying type when used as a template
9183 argument; we need them to be distinct so that we substitute into the
9184 specialization arguments at instantiation time. And aliases can't be
9185 equivalent without being ==, so we don't need to look any deeper.
9187 During partial ordering, however, we need to treat them normally so we can
9188 order uses of the same alias with different cv-qualification (79960). */
9194 /* For member templates */
9207 {
9211 }
9212 else
9213 {
9214 /* Try to treat a template non-type argument that has been converted
9215 to the parameter type as equivalent to one that hasn't yet. */
9229 }
9230 }
9232 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
9233 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
9234 NEWARG_PTR with the offending arguments if they are non-NULL. */
9236 int
9240 {
9253 {
9258 {
9264 }
9265 }
9267 }
9271 {
9273 }
9275 /* Implement a freelist interface for objects of type T.
9277 Head is a separate object, rather than a regular member, so that we
9278 can define it as a GTY deletable pointer, which is highly
9279 desirable. A data member could be declared that way, but then the
9280 containing object would implicitly get GTY((user)), which would
9281 prevent us from instantiating freelists as global objects.
9282 Although this way we can create freelist global objects, they're
9283 such thin wrappers that instantiating temporaries at every use
9284 loses nothing and saves permanent storage for the freelist object.
9286 Member functions next, anew, poison and reinit have default
9287 implementations that work for most of the types we're interested
9288 in, but if they don't work for some type, they should be explicitly
9289 specialized. See the comments before them for requirements, and
9290 the example specializations for the tree_list_freelist. */
9292 class freelist
9293 {
9294 /* Return the next object in a chain. We could just do type
9295 punning, but if we access the object with its underlying type, we
9296 avoid strict-aliasing trouble. This needs only work between
9297 poison and reinit. */
9300 /* Return a newly allocated, uninitialized or minimally-initialized
9301 object of type T. Any initialization performed by anew should
9302 either remain across the life of the object and the execution of
9303 poison, or be redone by reinit. */
9306 /* Optionally scribble all over the bits holding the object, so that
9307 they become (mostly?) uninitialized memory. This is called while
9308 preparing to make the object part of the free list. */
9313 #ifdef ENABLE_GC_CHECKING
9314 /* Poison the data, to indicate the data is garbage. */
9317 #endif
9318 /* Let valgrind know the object is free. */
9321 /* Let valgrind know the next portion of the object is available,
9322 but uninitialized. */
9324 }
9326 /* Bring an object that underwent at least one lifecycle after anew
9327 and before the most recent free and poison, back to a usable
9328 state, reinitializing whatever is needed for it to be
9329 functionally equivalent to an object just allocated and returned
9330 by anew. This may poison or clear the next field, used by
9331 freelist housekeeping after poison was called. */
9335 #ifdef ENABLE_GC_CHECKING
9337 #endif
9338 /* Let valgrind know the entire object is available, but
9339 uninitialized. */
9341 }
9343 /* Reference a GTY-deletable pointer that points to the first object
9344 in the free list proper. */
9347 /* Construct a freelist object chaining objects off of HEAD. */
9350 /* Add OBJ to the free object list. The former head becomes OBJ's
9351 successor. */
9353 {
9357 }
9359 /* Take an object from the free list, if one is available, or
9360 allocate a new one. Objects taken from the free list should be
9361 regarded as filled with garbage, except for bits that are
9362 configured to be preserved across free and alloc. */
9364 {
9366 {
9371 }
9372 else
9374 }
9375 };
9377 /* Explicitly specialize the interfaces for freelist<tree_node>: we
9378 want to allocate a TREE_LIST using the usual interface, and ensure
9379 TREE_CHAIN remains functional. Alas, we have to duplicate a bit of
9380 build_tree_list logic in reinit, so this could go out of sync. */
9384 {
9386 }
9388 inline tree
9390 {
9392 }
9396 {
9402 #ifdef ENABLE_GC_CHECKING
9405 /* Poison the data, to indicate the data is garbage. */
9408 #endif
9409 /* Let valgrind know the object is free. */
9411 /* But we still want to use the TREE_CODE and TREE_CHAIN parts. */
9415 #ifdef ENABLE_GC_CHECKING
9417 /* Keep TREE_CHAIN functional. */
9419 #else
9421 #endif
9422 }
9426 {
9429 #ifdef ENABLE_GC_CHECKING
9433 #endif
9435 /* Let valgrind know the entire object is available, but
9436 uninitialized. */
9439 #ifdef ENABLE_GC_CHECKING
9441 #else
9443 #endif
9444 }
9446 /* Point to the first object in the TREE_LIST freelist. */
9448 /* Return the/an actual TREE_LIST freelist. */
9451 {
9453 }
9455 /* Point to the first object in the tinst_level freelist. */
9457 /* Return the/an actual tinst_level freelist. */
9460 {
9462 }
9464 /* Point to the first object in the pending_template freelist. */
9466 /* Return the/an actual pending_template freelist. */
9469 {
9471 }
9473 /* Build the TREE_LIST object out of a split list, store it
9474 permanently, and return it. */
9475 tree
9477 {
9486 }
9490 /* Increment OBJ's refcount unless it is already infinite. */
9493 {
9497 }
9499 /* Release storage for OBJ and node, if it's a TREE_LIST. */
9500 void
9502 {
9506 }
9508 /* Decrement OBJ's refcount if not infinite. If it reaches zero, release
9509 OBJ's DECL and OBJ, and start over with the tinst_level object that
9510 used to be referenced by OBJ's NEXT. */
9511 static void
9513 {
9517 {
9521 }
9522 }
9524 /* Modify PTR so that it points to OBJ, adjusting the refcounts of OBJ
9525 and of the former PTR. Omitting the second argument is equivalent
9526 to passing (T*)NULL; this is allowed because passing the
9527 zero-valued integral constant NULL confuses type deduction and/or
9528 overload resolution. */
9530 static void
9532 {
9536 }
9538 static void
9540 {
9550 /* We are called both from instantiate_decl, where we've already had a
9551 tinst_level pushed, and instantiate_template, where we haven't.
9552 Compensate. */
9554 level = !current_tinst_level
9566 else
9575 }
9578 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
9579 ARGLIST. Valid choices for FNS are given in the cp-tree.def
9580 documentation for TEMPLATE_ID_EXPR. */
9582 tree
9584 {
9591 {
9594 }
9597 {
9600 unknown_type_node,
9602 arglist);
9604 }
9607 }
9609 /* Within the scope of a template class S<T>, the name S gets bound
9610 (in build_self_reference) to a TYPE_DECL for the class, not a
9611 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
9612 or one of its enclosing classes, and that type is a template,
9613 return the associated TEMPLATE_DECL. Otherwise, the original
9614 DECL is returned.
9616 Also handle the case when DECL is a TREE_LIST of ambiguous
9617 injected-class-names from different bases. */
9619 tree
9621 {
9625 /* DR 176: A lookup that finds an injected-class-name (10.2
9626 [class.member.lookup]) can result in an ambiguity in certain cases
9627 (for example, if it is found in more than one base class). If all of
9628 the injected-class-names that are found refer to specializations of
9629 the same class template, and if the name is followed by a
9630 template-argument-list, the reference refers to the class template
9631 itself and not a specialization thereof, and is not ambiguous. */
9633 {
9636 {
9642 }
9645 else
9647 }
9653 }
9655 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
9656 parameters, find the desired type.
9658 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
9660 IN_DECL, if non-NULL, is the template declaration we are trying to
9661 instantiate.
9663 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
9664 the class we are looking up.
9666 Issue error and warning messages under control of COMPLAIN.
9668 If the template class is really a local class in a template
9669 function, then the FUNCTION_CONTEXT is the function in which it is
9670 being instantiated.
9672 ??? Note that this function is currently called *twice* for each
9673 template-id: the first time from the parser, while creating the
9674 incomplete type (finish_template_type), and the second type during the
9675 real instantiation (instantiate_template_class). This is surely something
9676 that we want to avoid. It also causes some problems with argument
9677 coercion (see convert_nontype_argument for more information on this). */
9679 static tree
9682 {
9684 tree t;
9687 spec_entry elt;
9688 hashval_t hash;
9691 {
9695 else
9696 {
9703 }
9706 }
9708 {
9711 /* If we are declaring a constructor, say A<T>::A<T>, we will get
9712 an implicit typename for the second A. Deal with it. */
9717 {
9720 }
9721 }
9724 {
9727 }
9729 {
9733 }
9735 {
9738 }
9740 /* Issue an error message if we didn't find a template. */
9742 {
9746 }
9749 /* Make sure it's a user visible template, if it was named by
9750 the user. */
9753 {
9755 {
9759 }
9761 }
9765 /* An alias that just changes the name of a template is equivalent to the
9766 other template, so if any of the arguments are pack expansions, strip
9767 the alias to avoid problems with a pack expansion passed to a non-pack
9768 alias template parameter (DR 1430). */
9773 {
9774 tree parm;
9783 }
9784 else
9785 {
9787 tree gen_tmpl;
9788 tree type_decl;
9796 /* An error occurred while building the template TEMPL, and a
9797 diagnostic has most certainly been emitted for that
9798 already. Let's propagate that error. */
9810 {
9811 /* We've been given an incomplete set of template arguments.
9812 For example, given:
9814 template <class T> struct S1 {
9815 template <class U> struct S2 {};
9816 template <class U> struct S2<U*> {};
9817 };
9819 we will be called with an ARGLIST of `U*', but the
9820 TEMPLATE will be `template <class T> template
9821 <class U> struct S1<T>::S2'. We must fill in the missing
9822 arguments. */
9826 }
9828 /* Now we should have enough arguments. */
9831 /* From here on, we're only interested in the most general
9832 template. */
9834 /* Shortcut looking up the current class scope again. */
9841 /* Calculate the BOUND_ARGS. These will be the args that are
9842 actually tsubst'd into the definition to create the
9843 instantiation. */
9845 complain,
9850 /* We were unable to bind the arguments. */
9853 /* In the scope of a template class, explicit references to the
9854 template class refer to the type of the template, not any
9855 instantiation of it. For example, in:
9857 template <class T> class C { void f(C<T>); }
9859 the `C<T>' is just the same as `C'. Outside of the
9860 class, however, such a reference is an instantiation. */
9864 {
9869 }
9871 /* If we already have this specialization, return it. */
9881 /* If the template's constraints are not satisfied,
9882 then we cannot form a valid type.
9884 Note that the check is deferred until after the hash
9885 lookup. This prevents redundant checks on previously
9886 instantiated specializations. */
9890 {
9892 {
9893 auto_diagnostic_group d;
9896 }
9898 }
9902 /* If the deduced arguments are invalid, then the binding
9903 failed. */
9907 complain))
9914 /* This occurs when the user has tried to define a tagged type
9915 in a scope that forbids it. We emitted an error during the
9916 parse. We didn't complete the bail out then, so here we
9917 are. */
9922 {
9925 }
9926 else
9935 /* Create the type. */
9937 {
9938 /* The user referred to a specialization of an alias
9939 template represented by GEN_TMPL.
9941 [temp.alias]/2 says:
9943 When a template-id refers to the specialization of an
9944 alias template, it is equivalent to the associated
9945 type obtained by substitution of its
9946 template-arguments for the template-parameters in the
9947 type-id of the alias template. */
9950 /* Note that the call above (by indirectly calling
9951 register_specialization in tsubst_decl) registers the
9952 TYPE_DECL representing the specialization of the alias
9953 template. So next time someone substitutes ARGLIST for
9954 the template parms into the alias template (GEN_TMPL),
9955 she'll get that TYPE_DECL back. */
9959 }
9961 {
9963 {
9974 }
9975 else
9976 {
9977 /* We don't want to call start_enum for this type, since
9978 the values for the enumeration constants may involve
9979 template parameters. And, no one should be interested
9980 in the enumeration constants for such a type. */
9983 }
9987 }
9989 {
9990 /* Lambda closures are regenerated in tsubst_lambda_expr, not
9991 instantiated here. */
9999 /* A local class. Make sure the decl gets registered properly. */
10006 /* This instantiation is another name for the primary
10007 template type. Set the TYPE_CANONICAL field
10008 appropriately. */
10011 /* Some of the template arguments require structural
10012 equality testing, so this template class requires
10013 structural equality testing. */
10015 }
10016 else
10019 /* If we called start_enum or pushtag above, this information
10020 will already be set up. */
10023 {
10030 }
10033 /* Although GEN_TMPL is the TEMPLATE_DECL, it has the same value
10034 of export flag. We want to propagate this because it might
10035 be a friend declaration that pushes a new hidden binding. */
10039 {
10045 {
10048 }
10049 }
10053 {
10057 {
10058 tree attributes
10066 }
10067 }
10069 /* Let's consider the explicit specialization of a member
10070 of a class template specialization that is implicitly instantiated,
10071 e.g.:
10072 template<class T>
10073 struct S
10074 {
10075 template<class U> struct M {}; //#0
10076 };
10078 template<>
10079 template<>
10080 struct S<int>::M<char> //#1
10081 {
10082 int i;
10083 };
10084 [temp.expl.spec]/4 says this is valid.
10086 In this case, when we write:
10087 S<int>::M<char> m;
10089 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
10090 the one of #0.
10092 When we encounter #1, we want to store the partial instantiation
10093 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
10095 For all cases other than this "explicit specialization of member of a
10096 class template", we just want to store the most general template into
10097 the CLASSTYPE_TI_TEMPLATE of M.
10099 This case of "explicit specialization of member of a class template"
10100 only happens when:
10101 1/ the enclosing class is an instantiation of, and therefore not
10102 the same as, the context of the most general template, and
10103 2/ we aren't looking at the partial instantiation itself, i.e.
10104 the innermost arguments are not the same as the innermost parms of
10105 the most general template.
10107 So it's only when 1/ and 2/ happens that we want to use the partial
10108 instantiation of the member template in lieu of its most general
10109 template. */
10113 /* the enclosing class must be an instantiation... */
10116 {
10120 tree partial_inst_args =
10127 use_partial_inst_tmpl =
10128 /*...and we must not be looking at the partial instantiation
10129 itself. */
10131 partial_inst_args);
10132 }
10135 /* This case is easy; there are no member templates involved. */
10137 else
10138 {
10139 /* This is a full instantiation of a member template. Find
10140 the partial instantiation of which this is an instance. */
10142 /* Temporarily reduce by one the number of levels in the ARGLIST
10143 so as to avoid comparing the last set of arguments. */
10145 /* We don't use COMPLAIN in the following call because this isn't
10146 the immediate context of deduction. For instance, tf_partial
10147 could be set here as we might be at the beginning of template
10148 argument deduction when any explicitly specified template
10149 arguments are substituted into the function type. tf_partial
10150 could lead into trouble because we wouldn't find the partial
10151 instantiation that might have been created outside tf_partial
10152 context, because the levels of template parameters wouldn't
10153 match, because in a tf_partial context, tsubst doesn't reduce
10154 TEMPLATE_PARM_LEVEL. */
10157 /* FOUND is either a proper class type, or an alias
10158 template specialization. In the later case, it's a
10159 TYPE_DECL, resulting from the substituting of arguments
10160 for parameters in the TYPE_DECL of the alias template
10161 done earlier. So be careful while getting the template
10162 of FOUND. */
10164 ? found
10171 {
10172 /* If this partial instantiation is specialized, we want to
10173 use it for hash table lookup. */
10177 }
10178 }
10180 /* Build template info for the new specialization. */
10190 /* Note this use of the partial instantiation so we can check it
10191 later in maybe_process_partial_specialization. */
10199 /* Now that the type has been registered on the instantiations
10200 list, we set up the enumerators. Because the enumeration
10201 constants may involve the enumeration type itself, we make
10202 sure to register the type first, and then create the
10203 constants. That way, doing tsubst_expr for the enumeration
10204 constants won't result in recursive calls here; we'll find
10205 the instantiation and exit above. */
10209 /* If the type makes use of template parameters, the
10210 code that generates debugging information will crash. */
10213 /* Possibly limit visibility based on template args. */
10220 }
10221 }
10223 /* Wrapper for lookup_template_class_1. */
10225 tree
10228 {
10229 tree ret;
10235 }
10237 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
10239 tree
10241 {
10245 /* The type of the expression is NULL_TREE since the template-id could refer
10246 to an explicit or partial specialization. */
10248 }
10250 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
10252 tree
10254 {
10266 {
10268 {
10269 auto_diagnostic_group d;
10272 }
10274 }
10277 }
10279 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
10280 TARGS template args, and instantiate it if it's not dependent. */
10282 tree
10284 tsubst_flags_t complain)
10285 {
10288 {
10291 }
10294 }
10296 /* If the set of template parameters PARMS contains a template parameter
10297 at the given LEVEL and INDEX, then return this parameter. Otherwise
10298 return NULL_TREE. */
10300 static tree
10302 {
10311 /* As in template_parm_to_arg. */
10314 else
10319 }
10321 /* Return the template parameter from PARMS that positionally corresponds
10322 to the template parameter PARM, or else return NULL_TREE. */
10324 static tree
10326 {
10330 }
10332 \f
10333 struct pair_fn_data
10334 {
10335 tree_fn_t fn;
10336 tree_fn_t any_fn;
10338 /* True when we should also visit template parameters that occur in
10339 non-deduced contexts. */
10342 };
10344 /* Called from for_each_template_parm via walk_tree. */
10346 static tree
10348 {
10355 #define WALK_SUBTREE(NODE) \
10356 do \
10357 { \
10358 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
10359 pfd->include_nondeduced_p, \
10360 pfd->any_fn); \
10361 if (result) goto out; \
10362 } \
10363 while (0)
10373 {
10377 /* Fall through. */
10383 else
10393 /* Since we're not going to walk subtrees, we have to do this
10394 explicitly here. */
10396 /* Fall through. */
10399 /* Check the return type. */
10402 /* Check the parameter types. Since default arguments are not
10403 instantiated until they are needed, the TYPE_ARG_TYPES may
10404 contain expressions that involve template parameters. But,
10405 no-one should be looking at them yet. And, once they're
10406 instantiated, they don't contain template parameters, so
10407 there's no point in looking at them then, either. */
10408 {
10409 tree parm;
10414 /* Since we've already handled the TYPE_ARG_TYPES, we don't
10415 want walk_tree walking into them itself. */
10417 }
10420 {
10424 }
10443 /* Fall through. */
10455 /* Record template parameters such as `T' inside `TT<T>'. */
10457 /* Fall through. */
10469 /* A template template parameter is encountered. */
10473 /* Already substituted template template parameter */
10478 /* A template-id in a TYPENAME_TYPE might be a deduced context after
10479 partial instantiation. */
10492 /* If there's no type, then this thing must be some expression
10493 involving template parameters. */
10502 /* These are non-deduced contexts. */
10523 {
10527 /* Recursively walk the type of each constraint variable. */
10530 {
10533 }
10534 }
10539 }
10541 #undef WALK_SUBTREE
10543 /* We didn't find any template parameters we liked. */
10544 out:
10546 }
10548 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
10549 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
10550 call FN with the parameter and the DATA.
10551 If FN returns nonzero, the iteration is terminated, and
10552 for_each_template_parm returns 1. Otherwise, the iteration
10553 continues. If FN never returns a nonzero value, the value
10554 returned by for_each_template_parm is 0. If FN is NULL, it is
10555 considered to be the function which always returns 1.
10557 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
10558 parameters that occur in non-deduced contexts. When false, only
10559 visits those template parameters that can be deduced. */
10561 static tree
10565 tree_fn_t any_fn)
10566 {
10568 tree result;
10570 /* Set up. */
10576 /* Walk the tree. (Conceptually, we would like to walk without
10577 duplicates, but for_each_template_parm_r recursively calls
10578 for_each_template_parm, so we would need to reorganize a fair
10579 bit to use walk_tree_without_duplicates, so we keep our own
10580 visited list.) */
10583 else
10586 for_each_template_parm_r,
10590 /* Clean up. */
10592 {
10595 }
10598 }
10600 struct find_template_parameter_info
10601 {
10606 {}
10610 tree parm_list;
10611 tree ctx_parms;
10613 };
10615 /* Appends the declaration of T to the list in DATA. */
10617 static int
10619 {
10622 /* Template parameters declared within the expression are not part of
10623 the parameter mapping. For example, in this concept:
10625 template<typename T>
10626 concept C = requires { <expr> } -> same_as<int>;
10628 the return specifier same_as<int> declares a new decltype parameter
10629 that must not be part of the parameter mapping. The same is true
10630 for generic lambda parameters, lambda template parameters, etc. */
10638 /* We want the underlying TEMPLATE_TEMPLATE_PARM, not the
10639 BOUND_TEMPLATE_TEMPLATE_PARM itself. */
10642 /* This template parameter might be an argument to a cached dependent
10643 specalization that was formed earlier inside some other template, in
10644 which case the parameter is not among the ones that are in-scope.
10645 Look in CTX_PARMS to find the corresponding in-scope template
10646 parameter, and use it instead. */
10650 /* Arguments like const T yield parameters like const T. This means that
10651 a template-id like X<T, const T> would yield two distinct parameters:
10652 T and const T. Adjust types to their unqualified versions. */
10658 /* Verify the parameter we found has a valid index. */
10660 {
10666 }
10669 }
10671 /* Ensure that we recursively examine certain terms that are not normally
10672 visited in for_each_template_parm_r. */
10674 static int
10676 {
10679 #define WALK_SUBTREE(NODE) \
10680 do \
10681 { \
10682 for_each_template_parm (NODE, keep_template_parm, data, \
10683 &ftpi->visited, true, \
10684 any_template_parm_r); \
10685 } \
10686 while (0)
10688 /* A mention of a member alias/typedef is a use of all of its template
10689 arguments, including those from the enclosing class, so we don't use
10690 alias_template_specialization_p here. */
10696 {
10698 /* Type constraints of a placeholder type may contain parameters. */
10705 /* Search through references to variable templates. */
10712 /* A parameter or constraint variable may also depend on a template
10713 parameter without explicitly naming it. */
10718 /* If T is a member template that shares template parameters with
10719 ctx_parms, we need to mark all those parameters for mapping.
10720 To that end, it should suffice to just walk the DECL_CONTEXT of
10721 the template (assuming the template is not overly general). */
10726 {
10727 /* Look in the parms and body. */
10731 }
10736 /* The conversion-type-id of a conversion operator may be dependent. */
10742 }
10744 /* Keep walking. */
10746 }
10748 /* Returns a list of unique template parameters found within T, where CTX_PARMS
10749 are the template parameters in scope. */
10751 tree
10753 {
10761 }
10763 /* Returns true if T depends on any template parameter. */
10765 int
10767 {
10788 else
10794 }
10796 /* Returns true iff we're processing an incompletely instantiated function
10797 template. Useful instead of processing_template_decl because the latter
10798 is set to 0 during instantiate_non_dependent_expr. */
10800 bool
10802 {
10803 /* Inspect the less volatile cfun->decl instead of current_function_decl;
10804 the latter might get set for e.g. access checking during satisfaction. */
10813 }
10815 /* Returns true if T depends on any template parameter with level LEVEL. */
10817 bool
10819 {
10822 }
10824 /* Returns true if the signature of DECL depends on any template parameter from
10825 its enclosing class. */
10827 bool
10829 {
10838 {
10841 {
10846 template_parm_outer_level,
10856 }
10857 }
10865 }
10867 /* Returns TRUE iff INST is an instantiation we don't need to do in an
10868 ill-formed translation unit, i.e. a variable or function that isn't
10869 usable in a constant expression. */
10873 {
10878 }
10880 /* Returns TRUE iff we should refuse to instantiate DECL because it's
10881 neglectable and instantiated from within an erroneous instantiation. */
10883 static bool
10885 {
10896 }
10904 /* We're starting to instantiate D; record the template instantiation context
10905 at LOC for diagnostics and to restore it later. */
10907 bool
10909 {
10913 {
10914 /* Tell error.c not to try to instantiate any templates. */
10917 "template instantiation depth exceeds maximum of %d"
10919 max_tinst_depth);
10921 }
10923 /* If the current instantiation caused problems, don't let it instantiate
10924 anything else. Do allow deduction substitution and decls usable in
10925 constant expressions. */
10927 {
10928 /* Avoid no_linkage_errors and unused function (and all other)
10929 warnings for this decl. */
10932 }
10934 /* When not -quiet, dump template instantiations other than functions, since
10935 announce_function will take care of those. */
10957 }
10959 /* We're starting substitution of TMPL<ARGS>; record the template
10960 substitution context for diagnostics and to restore it later. */
10962 bool
10964 {
10966 }
10968 /* We're starting to instantiate D; record INPUT_LOCATION and the
10969 template instantiation context for diagnostics and to restore it
10970 later. */
10972 bool
10974 {
10976 }
10978 /* Likewise, but record LOC as the program location. */
10980 bool
10982 {
10985 }
10987 /* We're done instantiating this template; return to the instantiation
10988 context. */
10990 void
10992 {
10993 /* Restore the filename and line number stashed away when we started
10994 this instantiation. */
10998 }
11000 /* We're instantiating a deferred template; restore the template
11001 instantiation context in which the instantiation was requested, which
11002 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
11004 static tree
11006 {
11018 }
11020 /* Returns the TINST_LEVEL which gives the original instantiation
11021 context. */
11025 {
11031 }
11033 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
11034 vector of template arguments, as for tsubst.
11036 Returns an appropriate tsubst'd friend declaration. */
11038 static tree
11040 {
11041 tree new_friend;
11046 /* This was a friend declared with an explicit template
11047 argument list, e.g.:
11049 friend void f<>(T);
11051 to indicate that f was a template instantiation, not a new
11052 function declaration. Now, we have to figure out what
11053 instantiation of what template. */
11054 {
11056 tree new_args;
11057 tree tmpl;
11060 /* Friend functions are looked up in the containing namespace scope.
11061 We must enter that scope, to avoid finding member functions of the
11062 current class with same name. */
11077 tsk_none);
11079 }
11085 /* The NEW_FRIEND will look like an instantiation, to the
11086 compiler, but is not an instantiation from the point of view of
11087 the language. For example, we might have had:
11089 template <class T> struct S {
11090 template <class U> friend void f(T, U);
11091 };
11093 Then, in S<int>, template <class U> void f(int, U) is not an
11094 instantiation of anything. */
11098 {
11104 /* Substitute TEMPLATE_PARMS_CONSTRAINTS so that parameter levels will
11105 match in decls_match. */
11110 }
11112 /* The mangled name for the NEW_FRIEND is incorrect. The function
11113 is not a template instantiation and should not be mangled like
11114 one. Therefore, we forget the mangling here; we'll recompute it
11115 later if we need it. */
11117 {
11120 }
11123 {
11124 tree old_decl;
11125 tree ns;
11127 /* We must save some information from NEW_FRIEND before calling
11128 duplicate decls since that function will free NEW_FRIEND if
11129 possible. */
11139 {
11140 /* This declaration is a `primary' template. */
11145 }
11147 /* Inside pushdecl_namespace_level, we will push into the
11148 current namespace. However, the friend function should go
11149 into the namespace of the template. */
11159 {
11160 /* This new friend declaration matched an existing
11161 declaration. For example, given:
11163 template <class T> void f(T);
11164 template <class U> class C {
11165 template <class T> friend void f(T) {}
11166 };
11168 the friend declaration actually provides the definition
11169 of `f', once C has been instantiated for some type. So,
11170 old_decl will be the out-of-class template declaration,
11171 while new_friend is the in-class definition.
11173 But, if `f' was called before this point, the
11174 instantiation of `f' will have DECL_TI_ARGS corresponding
11175 to `T' but not to `U', references to which might appear
11176 in the definition of `f'. Previously, the most general
11177 template for an instantiation of `f' was the out-of-class
11178 version; now it is the in-class version. Therefore, we
11179 run through all specialization of `f', adding to their
11180 DECL_TI_ARGS appropriately. In particular, they need a
11181 new set of outer arguments, corresponding to the
11182 arguments for this class instantiation.
11184 The same situation can arise with something like this:
11186 friend void f(int);
11187 template <class T> class C {
11188 friend void f(T) {}
11189 };
11191 when `C<int>' is instantiated. Now, `f(int)' is defined
11192 in the class. */
11195 /* On the other hand, if the in-class declaration does
11196 *not* provide a definition, then we don't want to alter
11197 existing definitions. We can just leave everything
11198 alone. */
11199 ;
11200 else
11201 {
11205 /* Overwrite whatever template info was there before, if
11206 any, with the new template information pertaining to
11207 the declaration. */
11211 {
11212 /* We should have called reregister_specialization in
11213 duplicate_decls. */
11218 /* Instantiate it if the global has already been used. */
11222 }
11223 else
11224 {
11225 tree t;
11227 /* Indicate that the old function template is a partial
11228 instantiation. */
11236 /* Reassign any specializations already in the hash table
11237 to the new more general template, and add the
11238 additional template args. */
11242 {
11244 spec_entry elt;
11256 register_specialization
11259 }
11261 }
11262 }
11264 /* The information from NEW_FRIEND has been merged into OLD_DECL
11265 by duplicate_decls. */
11267 }
11268 }
11269 else
11270 {
11274 /* In the code
11275 template <class T> class C {
11276 template <class U> friend void C1<U>::f (); // case 1
11277 friend void C2<T>::f (); // case 2
11278 };
11279 we only need to make sure CONTEXT is a complete type for
11280 case 2. To distinguish between the two cases, we note that
11281 CONTEXT of case 1 remains dependent type after tsubst while
11282 this isn't true for case 2. */
11292 {
11294 /* do_friend adds the TEMPLATE_DECL for any member friend
11295 template even if it isn't a member template, i.e.
11296 template <class T> friend A<T>::f();
11297 Look through it in that case. */
11301 /* Check to see that the declaration is really present, and,
11302 possibly obtain an improved declaration. */
11307 }
11308 }
11311 }
11313 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
11314 template arguments, as for tsubst.
11316 Returns an appropriate tsubst'd friend type or error_mark_node on
11317 failure. */
11319 static tree
11321 {
11322 tree tmpl;
11325 {
11328 }
11333 else
11334 {
11337 }
11343 {
11344 /* The friend template has already been declared. Just
11345 check to see that the declarations match, and install any new
11346 default parameters. We must tsubst the default parameters,
11347 of course. We only need the innermost template parameters
11348 because that is all that redeclare_class_template will look
11349 at. */
11352 {
11360 }
11361 }
11362 else
11363 {
11364 /* The friend template has not already been declared. In this
11365 case, the instantiation of the template class will cause the
11366 injection of this template into the namespace scope. */
11370 {
11371 /* The new TMPL is not an instantiation of anything, so we
11372 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
11373 for the new type because that is supposed to be the
11374 corresponding template decl, i.e., TMPL. */
11381 /* Substitute into and set the constraints on the new declaration. */
11383 {
11389 }
11391 /* Inject this template into the enclosing namspace scope. */
11393 }
11394 }
11398 else
11402 }
11404 /* Returns zero if TYPE cannot be completed later due to circularity.
11405 Otherwise returns one. */
11407 static int
11409 {
11419 else
11421 }
11426 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
11427 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
11429 static tree
11432 {
11441 {
11448 clauses
11452 else
11454 }
11458 {
11460 tree varid
11471 {
11475 {
11477 {
11485 }
11486 else
11487 {
11491 {
11492 bool allow_string
11504 {
11505 location_t loc
11507 match_loc);
11513 "integer expression or string "
11515 else
11519 }
11522 {
11523 location_t loc
11525 match_loc);
11529 }
11531 }
11532 }
11533 }
11534 }
11536 }
11537 /* If the first attribute argument is an identifier, don't
11538 pass it through tsubst. Attributes like mode, format,
11539 cleanup and several target specific attributes expect it
11540 unmodified. */
11542 {
11543 tree chain
11548 }
11550 {
11551 /* An attribute pack expansion. */
11560 {
11564 }
11566 }
11567 else
11576 }
11578 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
11579 unchanged or a new TREE_LIST chain. */
11581 static tree
11584 {
11589 {
11593 }
11597 {
11600 {
11603 {
11609 }
11610 }
11612 }
11615 }
11617 /* Apply any attributes which had to be deferred until instantiation
11618 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
11619 ARGS, COMPLAIN, IN_DECL are as tsubst. Returns true normally,
11620 false on error. */
11622 static bool
11625 {
11626 tree t;
11633 {
11637 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
11638 to our attributes parameter. */
11640 }
11641 else
11642 {
11644 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
11645 lookup_template_class_1, and should be preserved. */
11649 }
11651 /* save_template_attributes puts the dependent attributes at the beginning of
11652 the list; find the non-dependent ones. */
11658 /* Apply any non-dependent attributes. */
11661 /* And then any dependent ones. */
11665 {
11670 {
11673 }
11676 }
11681 }
11683 /* The template TMPL is being instantiated with the template arguments TARGS.
11684 Perform the access checks that we deferred when parsing the template. */
11686 static void
11688 {
11698 {
11706 /* Make access check error messages point to the location
11707 of the use of the typedef. */
11711 }
11712 }
11714 static tree
11716 {
11718 tree typedecl;
11719 tree pbinfo;
11720 tree base_list;
11722 tree fn_context;
11731 /* Figure out which template is being instantiated. */
11735 /* Mark the type as in the process of being defined. */
11738 /* We may be in the middle of deferred access check. Disable
11739 it now. */
11742 /* Determine what specialization of the original template to
11743 instantiate. */
11748 {
11749 /* This TYPE is actually an instantiation of a partial
11750 specialization. We replace the innermost set of ARGS with
11751 the arguments appropriate for substitution. For example,
11752 given:
11754 template <class T> struct S {};
11755 template <class T> struct S<T*> {};
11757 and supposing that we are instantiating S<int*>, ARGS will
11758 presently be {int*} -- but we need {int}. */
11761 }
11762 else
11763 {
11766 }
11768 /* If the template we're instantiating is incomplete, then clearly
11769 there's nothing we can do. */
11771 {
11772 /* We can try again later. */
11775 }
11777 /* If we've recursively instantiated too many templates, stop. */
11785 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
11790 else
11791 {
11794 }
11795 /* Use #pragma pack from the template context. */
11801 /* Set the input location to the most specialized template definition.
11802 This is needed if tsubsting causes an error. */
11816 {
11819 /* Adjust visibility for template arguments. */
11821 }
11827 /* We should never instantiate a nested class before its enclosing
11828 class; we need to look up the nested class by name before we can
11829 instantiate it, and that lookup should instantiate the enclosing
11830 class. */
11835 /* Defer access checking while we substitute into the types named in
11836 the base-clause. */
11839 {
11840 tree pbase_binfo;
11843 /* Substitute into each of the bases to determine the actual
11844 basetypes. */
11846 {
11847 tree base;
11853 {
11854 expanded_bases =
11861 }
11864 {
11866 /* Extract the already-expanded base class. */
11868 else
11869 /* Substitute to figure out the base class. */
11871 NULL_TREE);
11879 }
11880 }
11882 /* The list is now in reverse order; correct that. */
11884 }
11885 /* Now call xref_basetypes to set up all the base-class
11886 information. */
11894 /* Now that our base classes are set up, enter the scope of the
11895 class, so that name lookups into base classes, etc. will work
11896 correctly. This is precisely analogous to what we do in
11897 begin_class_definition when defining an ordinary non-template
11898 class, except we also need to push the enclosing classes. */
11901 /* Now check accessibility of the types named in its base-clause,
11902 relative to the scope of the class. */
11905 /* A vector to hold members marked with attribute used. */
11908 /* Now members are processed in the order of declaration. */
11911 {
11915 {
11917 {
11919 /* A closure type for a lambda in an NSDMI or default argument.
11920 Ignore it; it will be regenerated when needed. */
11927 /* If the member is a class template, then -- even after
11928 substitution -- there may be dependent types in the
11929 template argument list for the class. We increment
11930 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
11931 that function will assume that no types are dependent
11932 when outside of a template. */
11942 {
11946 /* Unfortunately, lookup_template_class sets
11947 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
11948 instantiation (i.e., for the type of a member
11949 template class nested within a template class.)
11950 This behavior is required for
11951 maybe_process_partial_specialization to work
11952 correctly, but is not accurate in this case;
11953 the TAG is not an instantiation of anything.
11954 (The corresponding TEMPLATE_DECL is an
11955 instantiation, but the TYPE is not.) */
11958 /* Now, install the tag. We don't use pushtag
11959 because that does too much work -- creating an
11960 implicit typedef, which we've already done. */
11965 }
11966 }
11968 {
11969 tree r;
11978 /* Instantiate members marked with attribute used. */
11984 }
11987 /* A closure type for a lambda in an NSDMI or default argument.
11989 else
11990 {
11991 /* Build new TYPE_FIELDS. */
11996 {
11997 tree r;
12002 /* The file and line for this declaration, to
12003 assist in error message reporting. Since we
12004 called push_tinst_level above, we don't need to
12005 restore these. */
12015 {
12016 /* A capture pack became multiple fields. */
12019 }
12022 {
12026 {
12027 /* In [temp.inst]:
12029 [t]he initialization (and any associated
12030 side-effects) of a static data member does
12031 not occur unless the static data member is
12032 itself used in a way that requires the
12033 definition of the static data member to
12034 exist.
12036 Therefore, we do not substitute into the
12037 initialized for the static data member here. */
12038 finish_static_data_member_decl
12044 /* Instantiate members marked with attribute used. */
12047 }
12049 {
12050 /* Determine whether R has a valid type and can be
12051 completed later. If R is invalid, then its type
12052 is replaced by error_mark_node. */
12058 {
12059 /* If R's type couldn't be completed and
12060 it isn't a flexible array member (whose
12061 type is incomplete by definition) give
12062 an error. */
12065 }
12070 {
12073 }
12077 }
12079 /* If it is a TYPE_DECL for a class-scoped
12080 ENUMERAL_TYPE, such a thing will already have
12081 been added to the field list by tsubst_enum
12082 in finish_member_declaration case above. */
12086 {
12089 }
12090 }
12091 }
12092 }
12093 }
12094 else
12095 {
12098 {
12099 /* Build new CLASSTYPE_FRIEND_CLASSES. */
12105 {
12106 /* template <class T> friend class C; */
12109 }
12111 {
12112 /* template <class T> friend class C::D; */
12118 }
12121 {
12122 /* This could be either
12124 friend class T::C;
12126 when dependent_type_p is false or
12128 template <class U> friend class T::C;
12130 otherwise. */
12131 /* Bump processing_template_decl in case this is something like
12132 template <class T> friend struct A<T>::B. */
12139 }
12141 /* friend class C<T>; */
12145 /* Otherwise it's
12147 friend class C;
12149 where C is already declared or
12151 friend class C<int>;
12153 We don't have to do anything in these cases. */
12156 /* Trick make_friend_class into realizing that the friend
12157 we're adding is a template, not an ordinary class. It's
12158 important that we use make_friend_class since it will
12159 perform some error-checking and output cross-reference
12160 information. */
12168 }
12169 else
12170 {
12171 /* Build new DECL_FRIENDLIST. */
12172 tree r;
12174 /* The file and line for this declaration, to
12175 assist in error message reporting. Since we
12176 called push_tinst_level above, we don't need to
12177 restore these. */
12181 {
12184 }
12189 {
12192 }
12193 }
12194 }
12195 }
12198 {
12199 /* Restore these before substituting into the lambda capture
12200 initializers. */
12203 }
12205 /* Set the file and line number information to whatever is given for
12206 the class itself. This puts error messages involving generated
12207 implicit functions at a predictable point, and the same point
12208 that would be used for non-template classes. */
12215 /* We don't instantiate default arguments for member functions. 14.7.1:
12217 The implicit instantiation of a class template specialization causes
12218 the implicit instantiation of the declarations, but not of the
12219 definitions or default arguments, of the class member functions,
12220 member classes, static data members and member templates.... */
12230 /* The vtable for a template class can be emitted in any translation
12231 unit in which the class is instantiated. When there is no key
12232 method, however, finish_struct_1 will already have added TYPE to
12233 the keyed_classes. */
12237 /* Now that we've gone through all the members, instantiate those
12238 marked with attribute used. */
12243 }
12245 /* Wrapper for instantiate_class_template_1. */
12247 tree
12249 {
12250 tree ret;
12255 }
12257 tree
12259 {
12260 tree r;
12266 else
12267 {
12274 }
12277 }
12279 /* Given a function parameter pack TMPL_PARM and some function parameters
12280 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
12281 and set *SPEC_P to point at the next point in the list. */
12283 tree
12285 {
12286 /* Collect all of the extra "packed" parameters into an
12287 argument pack. */
12288 tree argpack;
12299 {
12300 /* The instantiation is still a parameter pack; don't wrap it in a
12301 NONTYPE_ARGUMENT_PACK. */
12304 }
12305 else
12306 {
12307 /* Fill in PARMVEC with all of the parameters. */
12311 {
12317 }
12319 /* Build the argument packs. */
12321 }
12325 }
12327 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
12328 NONTYPE_ARGUMENT_PACK. */
12330 static tree
12332 {
12334 }
12336 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
12337 pack expansion with no extra args, 2 if it has extra args, or 0
12338 if it is not a pack expansion. */
12340 static int
12342 {
12344 /* We're being called before this happens in tsubst_pack_expansion. */
12351 /* A decl pack is itself an expansion. */
12358 }
12361 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
12363 static tree
12365 {
12372 }
12374 /* This is a subroutine of tsubst_pack_expansion.
12376 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
12377 mechanism to store the (non complete list of) arguments of the
12378 substitution and return a non substituted pack expansion, in order
12379 to wait for when we have enough arguments to really perform the
12380 substitution. */
12382 static bool
12386 {
12387 /* If one pack has an expansion and another pack has a normal
12388 argument or if one pack has an empty argument and an another
12389 one hasn't then tsubst_pack_expansion cannot perform the
12390 substitution and need to fall back on the
12391 PACK_EXPANSION_EXTRA mechanism. */
12395 {
12396 /* If all the actual packs are pack expansions, we can still
12397 subsitute directly. */
12399 {
12409 }
12411 }
12414 {
12418 parm_pack;
12420 {
12425 /* We can't substitute a pack expansion with extra args into
12426 our pattern. */
12430 else
12432 }
12435 {
12438 }
12439 }
12441 }
12443 /* [temp.variadic]/6 says that:
12445 The instantiation of a pack expansion [...]
12446 produces a list E1,E2, ..., En, where N is the number of elements
12447 in the pack expansion parameters.
12449 This subroutine of tsubst_pack_expansion produces one of these Ei.
12451 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
12452 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
12453 PATTERN, and each TREE_VALUE is its corresponding argument pack.
12454 INDEX is the index 'i' of the element Ei to produce. ARGS,
12455 COMPLAIN, and IN_DECL are the same parameters as for the
12456 tsubst_pack_expansion function.
12458 The function returns the resulting Ei upon successful completion,
12459 or error_mark_node.
12461 Note that this function possibly modifies the ARGS parameter, so
12462 it's the responsibility of the caller to restore it. */
12464 static tree
12466 tree parm_packs,
12468 tree args /* This parm gets
12470 tsubst_flags_t complain,
12471 tree in_decl)
12472 {
12473 tree t;
12476 /* For each parameter pack, change the substitution of the parameter
12477 pack to the ith argument in its argument pack, then expand the
12478 pattern. */
12480 {
12485 ith_elem_is_expansion |=
12488 /* Select the Ith argument from the pack. */
12492 {
12494 {
12499 }
12500 else
12502 }
12503 else
12504 {
12509 {
12511 /* Update the corresponding argument. */
12513 }
12514 else
12515 /* Re-use the ARGUMENT_PACK_SELECT. */
12517 }
12519 }
12521 /* Substitute into the PATTERN with the (possibly altered)
12522 arguments. */
12524 /* Expanding a fixed parameter pack from
12525 coerce_template_parameter_pack. */
12532 else
12535 /* If the Ith argument pack element is a pack expansion, then
12536 the Ith element resulting from the substituting is going to
12537 be a pack expansion as well. */
12542 }
12544 /* When the unexpanded parameter pack in a fold expression expands to an empty
12545 sequence, the value of the expression is as follows; the program is
12546 ill-formed if the operator is not listed in this table.
12548 && true
12549 || false
12550 , void() */
12552 tree
12554 {
12558 {
12567 }
12573 }
12575 /* Given a fold-expression T and a current LEFT and RIGHT operand,
12576 form an expression that combines the two terms using the
12577 operator of T. */
12579 static tree
12581 {
12585 // Handle compound assignment operators.
12591 {
12599 complain);
12600 }
12601 }
12603 /* Substitute ARGS into the pack of a fold expression T. */
12607 {
12609 }
12611 /* Substitute ARGS into the pack of a fold expression T. */
12615 {
12617 }
12619 /* Expand a PACK of arguments into a grouped as left fold.
12620 Given a pack containing elements A0, A1, ..., An and an
12621 operator @, this builds the expression:
12623 ((A0 @ A1) @ A2) ... @ An
12625 Note that PACK must not be empty.
12627 The operator is defined by the original fold expression T. */
12629 static tree
12631 {
12634 {
12637 }
12639 }
12641 /* Substitute into a unary left fold expression. */
12643 static tree
12645 tree in_decl)
12646 {
12651 {
12655 }
12658 else
12660 }
12662 /* Substitute into a binary left fold expression.
12664 Do ths by building a single (non-empty) vector of argumnts and
12665 building the expression from those elements. */
12667 static tree
12669 tree in_decl)
12670 {
12679 {
12684 }
12692 }
12694 /* Expand a PACK of arguments into a grouped as right fold.
12695 Given a pack containing elementns A0, A1, ..., and an
12696 operator @, this builds the expression:
12698 A0@ ... (An-2 @ (An-1 @ An))
12700 Note that PACK must not be empty.
12702 The operator is defined by the original fold expression T. */
12704 tree
12706 {
12707 // Build the expression.
12711 {
12714 }
12716 }
12718 /* Substitute into a unary right fold expression. */
12720 static tree
12722 tree in_decl)
12723 {
12728 {
12732 }
12735 else
12737 }
12739 /* Substitute into a binary right fold expression.
12741 Do ths by building a single (non-empty) vector of arguments and
12742 building the expression from those elements. */
12744 static tree
12746 tree in_decl)
12747 {
12756 {
12761 }
12770 }
12772 /* Walk through the pattern of a pack expansion, adding everything in
12773 local_specializations to a list. */
12775 class el_data
12776 {
12778 /* Set of variables declared within the pattern. */
12780 /* Set of AST nodes that have been visited by the traversal. */
12782 /* List of local_specializations used within the pattern. */
12783 tree extra;
12784 tsubst_flags_t complain;
12788 };
12789 static tree
12791 {
12797 /* Remember local typedefs (85214). */
12801 {
12807 {
12810 decl2
12816 {
12819 }
12820 }
12821 }
12823 {
12824 /* Since we defer implicit capture, look in the parms and body. */
12830 }
12832 {
12834 /* Don't mess with variables declared within the pattern. */
12837 {
12838 /* Maybe pull out the PARM_DECL for a partial instantiation. */
12841 {
12847 }
12849 {
12850 /* Handle lambda capture here, since we aren't doing any
12851 substitution now, and so tsubst_copy won't call
12852 process_outer_var_ref. */
12856 {
12862 {
12863 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
12864 proxies. */
12866 {
12871 }
12873 }
12874 }
12875 }
12876 }
12880 }
12882 }
12883 static tree
12885 {
12889 }
12891 /* Extract any uses of local_specializations from PATTERN and add them to ARGS
12892 for use in PACK_EXPANSION_EXTRA_ARGS. */
12894 tree
12896 {
12897 /* Make a copy of the extra arguments so that they won't get changed
12898 out from under us. */
12904 }
12906 /* Apply any local specializations from PACK_EXPANSION_EXTRA_ARGS and add the
12907 normal template args to ARGS. */
12909 tree
12911 {
12913 {
12915 {
12916 /* The partial instantiation involved local declarations collected in
12917 extract_local_specs; map from the general template to our local
12918 context. */
12924 /* else inst is already a full instantiation of the pack. */
12926 }
12929 }
12931 {
12932 /* This can happen after dependent substitution into a
12933 requires-expr or a lambda that uses constexpr if. */
12936 }
12937 else
12940 }
12942 /* Substitute ARGS into T, which is an pack expansion
12943 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
12944 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
12945 (if only a partial substitution could be performed) or
12946 ERROR_MARK_NODE if there was an error. */
12947 tree
12949 tree in_decl)
12950 {
12951 tree pattern;
12955 tree result;
12962 /* Add in any args remembered from an earlier partial instantiation. */
12967 /* Determine the argument packs that will instantiate the parameter
12968 packs used in the expansion expression. While we're at it,
12969 compute the number of arguments to be expanded and make sure it
12970 is consistent. */
12973 {
12980 {
12986 complain);
12987 else
12991 }
12993 {
12995 {
12998 parm_pack);
13000 }
13003 }
13005 {
13006 /* We know we have correct local_specializations if this
13007 expansion is at function scope, or if we're dealing with a
13008 local parameter in a requires expression; for the latter,
13009 tsubst_requires_expr set it up appropriately. */
13012 else
13013 /* We can't rely on local_specializations for a parameter
13014 name used later in a function declaration (such as in a
13015 late-specified return type). Even if it exists, it might
13016 have the wrong value for a recursive call. */
13020 {
13021 /* This parameter pack was used in an unevaluated context. Just
13022 make a dummy decl, since it's only used for its type. */
13027 /* Partial instantiation of the parm_pack, we can't build
13028 up an argument pack yet. */
13030 else
13032 }
13034 /* This argument pack isn't fully instantiated yet. */
13036 }
13038 {
13042 }
13043 else
13044 {
13053 }
13060 /* This can only happen if we forget to expand an argument
13061 pack somewhere else. Just return an error, silently. */
13062 {
13066 }
13069 {
13073 /* Don't bother trying to do a partial substitution with
13074 incomplete packs; we'll try again after deduction. */
13081 {
13086 pattern);
13087 else
13089 pattern);
13091 }
13093 /* Keep track of the parameter packs and their corresponding
13094 argument packs. */
13097 }
13098 else
13099 {
13100 /* We can't substitute for this parameter pack. We use a flag as
13101 well as the missing_level counter because function parameter
13102 packs don't have a level. */
13105 }
13106 }
13108 /* If the expansion is just T..., return the matching argument pack, unless
13109 we need to call convert_from_reference on all the elements. This is an
13110 important optimization; see c++/68422. */
13113 {
13116 /* If the argument pack is a single pack expansion, pull it out. */
13121 /* Types need no adjustment, nor does sizeof..., and if we still have
13122 some pack expansion args we won't do anything yet. */
13127 /* Also optimize expression pack expansions if we can tell that the
13128 elements won't have reference type. */
13134 /* Otherwise use the normal path so we get convert_from_reference. */
13135 }
13137 /* We cannot expand this expansion expression, because we don't have
13138 all of the argument packs we need. */
13140 {
13141 /* We got some full packs, but we can't substitute them in until we
13142 have values for all the packs. So remember these until then. */
13148 }
13150 /* If NEED_LOCAL_SPECIALIZATIONS then we're in a late-specified return
13151 type, so create our own local specializations map; the current map is
13152 either NULL or (in the case of recursive unification) might have
13153 bindings that we don't want to use or alter. */
13158 {
13159 /* There were no real arguments, we're just replacing a parameter
13160 pack with another version of itself. Substitute into the
13161 pattern and return a PACK_EXPANSION_*. The caller will need to
13162 deal with that. */
13166 else
13172 {
13173 /* This is a fake auto... pack expansion created in add_capture with
13174 _PACKS that don't appear in the pattern. Copy one over. */
13181 }
13183 }
13187 /* For each argument in each argument pack, substitute into the
13188 pattern. */
13192 {
13194 i,
13196 in_decl);
13199 {
13202 }
13203 }
13205 /* Update ARGS to restore the substitution from parameter packs to
13206 their argument packs. */
13208 {
13215 else
13216 {
13224 /* Update the corresponding argument. */
13228 else
13230 }
13231 }
13233 /* If the dependent pack arguments were such that we end up with only a
13234 single pack expansion again, there's no need to keep it in a TREE_VEC. */
13240 }
13242 /* Make an argument pack out of the TREE_VEC VEC. */
13244 static tree
13246 {
13247 tree pack;
13251 else
13252 {
13255 }
13258 }
13260 /* Return an exact copy of template args T that can be modified
13261 independently. */
13263 static tree
13265 {
13273 {
13278 }
13284 }
13286 /* Substitute ARGS into the *_ARGUMENT_PACK orig_arg. */
13288 tree
13290 tree in_decl)
13291 {
13292 /* Substitute into each of the arguments. */
13297 {
13299 {
13302 }
13303 else
13304 {
13307 }
13310 }
13313 }
13315 /* Substitute ARGS into the vector or list of template arguments T. */
13317 tree
13319 {
13331 {
13333 tree new_arg;
13340 {
13341 /* Substitute into an expansion expression. */
13345 /* Add to the expanded length adjustment the number of
13346 expanded arguments. We subtract one from this
13347 measurement, because the argument pack expression
13348 itself is already counted as 1 in
13349 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
13350 the argument pack is empty. */
13352 }
13355 else
13364 }
13369 /* Make space for the expanded arguments coming from template
13370 argument packs. */
13372 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
13373 arguments for a member template.
13374 In that case each TREE_VEC in ORIG_T represents a level of template
13375 arguments, and ORIG_T won't carry any non defaulted argument count.
13376 It will rather be the nested TREE_VECs that will carry one.
13377 In other words, ORIG_T carries a non defaulted argument count only
13378 if it doesn't contain any nested TREE_VEC. */
13380 {
13384 }
13386 {
13391 {
13394 /* Now expand the template argument pack "in place". */
13397 }
13398 else
13399 {
13401 out++;
13402 }
13403 }
13406 }
13408 /* Substitute ARGS into one level PARMS of template parameters. */
13410 static tree
13412 {
13419 {
13427 }
13430 }
13432 /* Return the result of substituting ARGS into the template parameters
13433 given by PARMS. If there are m levels of ARGS and m + n levels of
13434 PARMS, then the result will contain n levels of PARMS. For
13435 example, if PARMS is `template <class T> template <class U>
13436 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
13437 result will be `template <int*, double, class V>'. */
13439 static tree
13441 {
13445 /* When substituting into a template, we must set
13446 PROCESSING_TEMPLATE_DECL as the template parameters may be
13447 dependent if they are based on one-another, and the dependency
13448 predicates are short-circuit outside of templates. */
13455 {
13464 }
13469 }
13471 /* Return the result of substituting ARGS into one template parameter
13472 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
13473 parameter and which TREE_PURPOSE is the default argument of the
13474 template parameter. */
13476 static tree
13478 {
13503 }
13505 /* Substitute the ARGS into the indicated aggregate (or enumeration)
13506 type T. If T is not an aggregate or enumeration type, it is
13507 handled as if by tsubst. IN_DECL is as for tsubst. If
13508 ENTERING_SCOPE is nonzero, T is the context for a template which
13509 we are presently tsubst'ing. Return the substituted value. */
13511 static tree
13513 tree args,
13514 tsubst_flags_t complain,
13515 tree in_decl,
13517 {
13522 {
13527 /* Fall through. */
13531 {
13532 tree argvec;
13533 tree context;
13534 tree r;
13536 /* In "sizeof(X<I>)" we need to evaluate "I". */
13537 cp_evaluated ev;
13539 /* First, determine the context for the type we are looking
13540 up. */
13543 {
13546 /* If context is a nested class inside a class template,
13547 it may still need to be instantiated (c++/33959). */
13549 }
13551 /* Then, figure out what arguments are appropriate for the
13552 type we are trying to find. For example, given:
13554 template <class T> struct S;
13555 template <class T, class U> void f(T, U) { S<U> su; }
13557 and supposing that we are instantiating f<int, double>,
13558 then our ARGS will be {int, double}, but, when looking up
13559 S we only want {double}. */
13566 {
13567 /* See maybe_dependent_member_ref. */
13574 typename_type);
13575 }
13576 else
13577 {
13581 }
13584 }
13585 else
13586 /* This is not a template type, so there's nothing to do. */
13591 }
13592 }
13596 /* Substitute into the default argument ARG (a default argument for
13597 FN), which has the indicated TYPE. */
13599 tree
13601 tsubst_flags_t complain)
13602 {
13605 /* This can happen in invalid code. */
13609 /* Shortcut {}. */
13628 /* This default argument came from a template. Instantiate the
13629 default argument here, not in tsubst. In the case of
13630 something like:
13632 template <class T>
13633 struct S {
13634 static T t();
13635 void f(T = t());
13636 };
13638 we must be careful to do name lookup in the scope of S<T>,
13639 rather than in the current class. */
13645 /* The default argument expression may cause implicitly defined
13646 member functions to be synthesized, which will result in garbage
13647 collection. We must treat this situation as if we were within
13648 the body of function so as to avoid collecting live data on the
13649 stack. */
13658 /* Make sure the default argument is reasonable. */
13671 {
13675 }
13678 }
13680 /* Substitute into all the default arguments for FN. */
13682 static void
13684 {
13685 tree arg;
13686 tree tmpl_args;
13690 /* If this function is not yet instantiated, we certainly don't need
13691 its default arguments. */
13694 /* Don't do this again for clones. */
13700 arg;
13706 complain);
13707 }
13709 /* Hash table mapping a FUNCTION_DECL to its dependent explicit-specifier. */
13712 /* Store a pair to EXPLICIT_SPECIFIER_MAP. */
13714 void
13716 {
13721 }
13723 /* Lookup an element in EXPLICIT_SPECIFIER_MAP. */
13725 static tree
13727 {
13729 }
13731 /* Given T, a FUNCTION_TYPE or METHOD_TYPE, construct and return a corresponding
13732 FUNCTION_TYPE or METHOD_TYPE whose return type is RETURN_TYPE, argument types
13733 are ARG_TYPES, and exception specification is RAISES, and otherwise is
13734 identical to T. */
13736 static tree
13739 {
13742 tree new_type;
13744 {
13747 }
13748 else
13749 {
13751 /* Don't pick up extra function qualifiers from the basetype. */
13754 {
13755 /* [temp.deduct]
13757 Type deduction may fail for any of the following
13758 reasons:
13760 -- Attempting to create "pointer to member of T" when T
13761 is not a class type. */
13764 r);
13766 }
13770 }
13776 }
13778 /* Check if the function type of DECL, a FUNCTION_DECL, agrees with the type of
13779 each of its formal parameters. If there is a disagreement then rebuild
13780 DECL's function type according to its formal parameter types, as part of a
13781 resolution for Core issues 1001/1322. */
13783 static void
13785 {
13788 {
13791 {
13795 {
13798 }
13802 }
13803 }
13814 {
13819 }
13821 {
13831 }
13839 }
13841 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
13843 static tree
13845 tree lambda_fntype)
13846 {
13851 /* Nobody should be tsubst'ing into non-template functions. */
13856 {
13859 }
13861 {
13862 /* If T is not dependent, just return it. */
13867 /* Calculate the most general template of which R is a
13868 specialization. */
13871 /* We're substituting a lambda function under tsubst_lambda_expr but not
13872 directly from it; find the matching function we're already inside.
13873 But don't do this if T is a generic lambda with a single level of
13874 template parms, as in that case we're doing a normal instantiation. */
13880 /* Calculate the complete set of arguments used to
13881 specialize R. */
13883 (DECL_TEMPLATE_RESULT
13889 /* Check to see if we already have this specialization. */
13891 {
13895 }
13896 }
13897 else
13898 {
13899 /* This special case arises when we have something like this:
13901 template <class T> struct S {
13902 friend void f<int>(int, double);
13903 };
13905 Here, the DECL_TI_TEMPLATE for the friend declaration
13906 will be an IDENTIFIER_NODE. We are being called from
13907 tsubst_friend_function, and we want only to create a
13908 new decl (R) with appropriate types so that we can call
13909 determine_specialization. */
13912 }
13929 /* If we hit excessive deduction depth, the type is bogus even if
13930 it isn't error_mark_node, so don't build a decl. */
13934 /* We do NOT check for matching decls pushed separately at this
13935 point, as they may not represent instantiations of this
13936 template, and in any case are considered separate under the
13937 discrete model. */
13941 /* Clear out the mangled name and RTL for the instantiation. */
13944 /* Leave DECL_INITIAL set on deleted instantiations. */
13950 /* Handle explicit(dependent-expr). */
13952 {
13959 }
13961 /* OpenMP UDRs have the only argument a reference to the declared
13962 type. We want to diagnose if the declared type is a reference,
13963 which is invalid, but as references to references are usually
13964 quietly merged, diagnose it here. */
13966 {
13967 tree argtype
13972 "reference type %qT in "
13976 argtype);
13977 }
13980 /* Type-conversion operator. Reconstruct the name, in
13981 case it's the name of one of the template's parameters. */
13991 {
13996 }
14005 /* If this is an instantiation of a function with internal
14006 linkage, we already know what object file linkage will be
14007 assigned to the instantiation. */
14016 /* We'll re-clone as appropriate in instantiate_template. */
14019 /* If we aren't complaining now, return on error before we register
14020 the specialization so that we'll complain eventually. */
14026 /* Associate the constraints directly with the instantiation. We
14027 don't substitute through the constraints; that's only done when
14028 they are checked. */
14041 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
14042 this in the special friend case mentioned above where
14043 GEN_TMPL is NULL. */
14045 {
14050 tree new_r
14053 /* We instantiated this while substituting into
14054 the type earlier (template/friend54.C). */
14057 /* We're not supposed to instantiate default arguments
14058 until they are called, for a template. But, for a
14059 declaration like:
14061 template <class T> void f ()
14062 { extern void g(int i = T()); }
14064 we should do the substitution when the template is
14065 instantiated. We handle the member function case in
14066 instantiate_class_template since the default arguments
14067 might refer to other members of the class. */
14072 }
14074 {
14077 }
14078 else
14081 /* Copy the list of befriending classes. */
14085 {
14089 }
14092 {
14096 /* If this is an instantiation of a member template, clone it.
14097 If it isn't, that'll be handled by
14098 clone_constructors_and_destructors. */
14101 }
14107 /* Possibly limit visibility based on template args. */
14110 {
14114 }
14126 }
14128 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
14130 static tree
14132 tree lambda_fntype)
14133 {
14134 /* We can get here when processing a member function template,
14135 member class template, or template template parameter. */
14138 tree spec;
14139 tree tmpl_args;
14140 tree full_args;
14141 tree r;
14145 {
14146 /* Template template parameter is treated here. */
14150 /* If we get a real template back, return it. This can happen in
14151 the context of most_specialized_partial_spec. */
14154 else
14155 /* The new TEMPLATE_DECL was built in
14156 reduce_template_parm_level. */
14159 }
14162 {
14163 /* We might already have an instance of this template.
14164 The ARGS are for the surrounding class type, so the
14165 full args contain the tsubst'd args for the context,
14166 plus the innermost args from the template decl. */
14170 /* Because this is a template, the arguments will still be
14171 dependent, even after substitution. If
14172 PROCESSING_TEMPLATE_DECL is not set, the dependency
14173 predicates will short-circuit. */
14181 /* If this is a default template template argument,
14182 tsubst might not have changed anything. */
14189 {
14191 /* Type partial instantiations are stored as the type by
14192 lookup_template_class_1, not here as the template. */
14195 }
14196 }
14198 /* Make a new template decl. It will be similar to the
14199 original, but will record the current template arguments.
14200 We also create a new function declaration, which is just
14201 like the old one, but points to this new template, rather
14202 than the old one. */
14207 // Build new template info linking to the original template decl.
14209 {
14212 }
14213 else
14216 /* The template parameters for this new template are all the
14217 template parameters for the old template, except the
14218 outermost level of parameters. */
14221 = current_template_parms
14223 complain);
14230 else
14231 {
14233 {
14236 }
14240 else
14242 }
14248 {
14249 /* For a partial specialization, we need to keep pointing to
14250 the primary template. */
14256 }
14258 {
14261 }
14262 else
14263 {
14266 }
14273 {
14274 /* Propagate module information from the decl. */
14277 /* If this is a constrained template, the above tsubst of
14278 inner can find the unconstrained template, which may have
14279 come from an import. This is ok, because we don't
14280 register this instantiation (see below). */
14282 || (TEMPLATE_PARMS_CONSTRAINTS
14284 }
14293 /* Record this non-type partial instantiation. */
14299 }
14301 /* True if FN is the op() for a lambda in an uninstantiated template. */
14303 bool
14305 {
14310 }
14312 /* True if FN is the substitution (via tsubst_lambda_expr) of a function for
14313 which the above is true. */
14315 bool
14317 {
14323 }
14325 /* Return the LAMBDA_EXPR from which T was ultimately regenerated.
14326 If T is not a regenerated LAMBDA_EXPR, return T. */
14328 tree
14330 {
14334 }
14336 /* We're instantiating a variable from template function TCTX. Return the
14337 corresponding current enclosing scope. We can match them up using
14338 DECL_SOURCE_LOCATION because lambdas only ever have one source location, and
14339 the DECL_SOURCE_LOCATION for a function instantiation is updated to match
14340 the template definition in regenerate_decl_from_template. */
14342 static tree
14344 {
14347 /* We shouldn't ever need to do this for other artificial functions. */
14354 }
14356 /* Substitute the ARGS into the T, which is a _DECL. Return the
14357 result of the substitution. Issue error and warning messages under
14358 control of COMPLAIN. */
14360 static tree
14362 {
14363 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
14364 location_t saved_loc;
14369 /* Set the filename and linenumber to improve error-reporting. */
14374 {
14384 {
14392 {
14393 /* If there is a local specialization that isn't a
14394 parameter pack, it means that we're doing a "simple"
14395 substitution from inside tsubst_pack_expansion. Just
14396 return the local specialization (which will be a single
14397 parm). */
14404 /* Expand the TYPE_PACK_EXPANSION that provides the types for
14405 the parameters in this function parameter pack. */
14409 {
14412 /* Zero-length parameter packs are boring. Just substitute
14413 into the chain. */
14417 }
14418 else
14419 {
14420 /* All we did was update the type. Make a note of that. */
14423 }
14424 }
14426 /* Loop through all of the parameters we'll build. When T is
14427 a function parameter pack, LEN is the number of expanded
14428 types in EXPANDED_TYPES; otherwise, LEN is 1. */
14431 {
14438 /* We're on the Ith parameter of the function parameter
14439 pack. */
14440 {
14441 /* Get the Ith type. */
14444 /* Rename the parameter to include the index. */
14447 }
14449 /* We're dealing with a normal parameter. */
14457 {
14460 else
14463 }
14474 /* Keep track of the first new parameter we
14475 generate. That's what will be returned to the
14476 caller. */
14480 /* Build a proper chain of parameters when substituting
14481 into a function parameter pack. */
14484 }
14486 /* If cp_unevaluated_operand is set, we're just looking for a
14487 single dummy parameter, so don't keep going. */
14492 /* FIRST_R contains the start of the chain we've built. */
14494 }
14498 {
14505 {
14506 /* This field is a lambda capture pack. Return a TREE_VEC of
14507 the expanded fields to instantiate_class_template_1. */
14511 {
14514 }
14515 else
14516 {
14517 /* All we did was update the type. Make a note of that. */
14520 }
14521 }
14524 {
14527 {
14531 }
14541 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
14542 number of bits. */
14548 {
14549 /* Set up DECL_TEMPLATE_INFO so that we can get at the
14550 NSDMI in perform_member_init. Still set DECL_INITIAL
14551 so that we know there is one. */
14556 }
14557 /* We don't have to set DECL_CONTEXT here; it is set by
14558 finish_member_declaration. */
14567 }
14571 }
14575 /* We reach here only for member using decls. We also need to check
14576 uses_template_parms because DECL_DEPENDENT_P is not set for a
14577 using-declaration that designates a member of the current
14578 instantiation (c++/53549). */
14581 {
14585 {
14590 {
14594 {
14597 }
14598 else
14599 {
14602 }
14604 }
14605 }
14606 else
14607 {
14613 else
14614 {
14617 }
14618 }
14619 }
14620 else
14621 {
14624 }
14629 {
14640 {
14641 /* If this is the canonical decl, we don't have to
14642 mess with instantiations, and often we can't (for
14643 typename, template type parms and such). Note that
14644 TYPE_NAME is not correct for the above test if
14645 we've copied the type for a typedef. */
14651 }
14653 /* Check to see if we already have the specialization we
14654 need. */
14660 {
14663 {
14665 complain,
14667 /* If CTX is unchanged, then T is in fact the
14668 specialization we want. That situation occurs when
14669 referencing a static data member within in its own
14670 class. We can use pointer equality, rather than
14671 same_type_p, because DECL_CONTEXT is always
14672 canonical... */
14674 /* ... unless T is a member template; in which
14675 case our caller can be willing to create a
14676 specialization of that template represented
14677 by T. */
14681 }
14684 {
14689 argvec = (coerce_innermost_template_parms
14697 }
14698 }
14699 else
14700 {
14702 /* Subsequent calls to pushdecl will fill this in. */
14704 /* A local variable. */
14706 /* Unless this is a reference to a static variable from an
14707 enclosing function, in which case we need to fill it in now. */
14709 {
14713 }
14715 }
14716 /* If we already have the specialization we need, there is
14717 nothing more to do. */
14719 {
14722 }
14724 /* Create a new node for the specialization we need. */
14726 {
14729 else
14737 {
14738 /* Mask off any template args past the variable's context so we
14739 don't replace the auto with an unrelated argument. */
14743 /* This should never happen with the new lambda instantiation
14744 model, but keep the handling just in case. */
14747 }
14749 /* Substituting the type might have recursively instantiated this
14750 same alias (c++/86171). */
14753 {
14756 }
14757 }
14760 {
14766 {
14767 /* It may seem that this case cannot occur, since:
14769 typedef void f();
14770 void g() { f x; }
14772 declares a function, not a variable. However:
14774 typedef void f();
14775 template <typename T> void g() { T t; }
14776 template void g<f>();
14778 is an attempt to declare a variable with function
14779 type. */
14781 /* R is not yet sufficiently initialized, so we
14782 just use its name. */
14785 }
14787 /* Wait until cp_finish_decl to set this again, to handle
14788 circular dependency (template/instantiate6.C). */
14793 {
14795 /* If the DECL_VALUE_EXPR is converted to the declared type,
14796 preserve the identity so that gimplify_type_sizes works. */
14803 {
14806 }
14815 else
14819 }
14823 }
14829 /* Clear out the mangled name and RTL for the instantiation. */
14835 /* The initializer must not be expanded until it is required;
14836 see [temp.inst]. */
14840 {
14846 /* Possibly limit visibility based on template args. */
14849 {
14853 }
14855 }
14858 {
14859 /* A static data member declaration is always marked
14860 external when it is declared in-class, even if an
14861 initializer is present. We mimic the non-template
14862 processing here. */
14871 }
14872 else
14873 {
14878 }
14887 /* Preserve a typedef that names a type. */
14889 {
14892 }
14895 }
14900 }
14901 #undef RETURN
14903 out:
14904 /* Restore the file and line information. */
14908 }
14910 /* Substitute into the complete parameter type list PARMS. */
14912 tree
14914 tree args,
14915 tsubst_flags_t complain,
14916 tree in_decl)
14917 {
14919 }
14921 /* Substitute into the ARG_TYPES of a function type.
14922 If END is a TREE_CHAIN, leave it and any following types
14923 un-substituted. */
14925 static tree
14927 tree args,
14928 tree end,
14929 tsubst_flags_t complain,
14930 tree in_decl)
14931 {
14940 {
14941 /* For a pack expansion, perform substitution on the
14942 entire expression. Later on, we'll handle the arguments
14943 one-by-one. */
14948 /* So that we'll spin through the parameters, one by one. */
14950 else
14951 {
14952 /* We only partially substituted into the parameter
14953 pack. Our type is TYPE_PACK_EXPANSION. */
14956 }
14957 }
14958 else
14961 /* Check if a substituted type is erroneous before substituting into
14962 the rest of the chain. */
14964 {
14971 {
14973 {
14977 }
14979 }
14980 }
14982 /* We do not substitute into default arguments here. The standard
14983 mandates that they be instantiated only when needed, which is
14984 done in build_over_call. */
14987 /* Except that we do substitute default arguments under tsubst_lambda_expr,
14988 since the new op() won't have any associated template arguments for us
14989 to refer to later. */
15000 {
15004 /* Do array-to-pointer, function-to-pointer conversion, and ignore
15005 top-level qualifiers as required. */
15009 {
15010 /* We've instantiated a template before its default arguments
15011 have been parsed. This can happen for a nested template
15012 class, and is not an error unless we require the default
15013 argument in a call of this function. */
15014 remaining_arg_types
15017 remaining_arg_types);
15018 }
15019 else
15020 remaining_arg_types
15022 }
15025 }
15027 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
15028 *not* handle the exception-specification for FNTYPE, because the
15029 initial substitution of explicitly provided template parameters
15030 during argument deduction forbids substitution into the
15031 exception-specification:
15033 [temp.deduct]
15035 All references in the function type of the function template to the
15036 corresponding template parameters are replaced by the specified tem-
15037 plate argument values. If a substitution in a template parameter or
15038 in the function type of the function template results in an invalid
15039 type, type deduction fails. [Note: The equivalent substitution in
15040 exception specifications is done only when the function is instanti-
15041 ated, at which point a program is ill-formed if the substitution
15042 results in an invalid type.] */
15044 static tree
15046 tree args,
15047 tsubst_flags_t complain,
15048 tree in_decl)
15049 {
15050 tree return_type;
15053 /* The TYPE_CONTEXT is not used for function/method types. */
15056 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
15057 failure. */
15061 {
15062 /* Substitute the argument types. */
15074 {
15075 /* DR 1207: 'this' is in scope in the trailing return type. */
15077 }
15079 /* Substitute the return type. */
15083 {
15086 }
15087 }
15088 else
15089 /* Substitute the return type. */
15094 /* DR 486 clarifies that creation of a function type with an
15095 invalid return type is a deduction failure. */
15098 {
15100 {
15103 else
15105 }
15107 }
15110 {
15111 /* Substitute the argument types. */
15116 }
15118 /* Construct a new type node and return it. */
15121 }
15123 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
15124 ARGS into that specification, and return the substituted
15125 specification. If there is no specification, return NULL_TREE. */
15127 static tree
15129 tree args,
15130 tsubst_flags_t complain,
15131 tree in_decl,
15133 {
15134 tree specs;
15135 tree new_specs;
15140 {
15141 /* A noexcept-specifier. */
15146 {
15147 /* Defer instantiation of noexcept-specifiers to avoid
15148 excessive instantiations (c++/49107). */
15151 {
15152 /* We already partially instantiated this member template,
15153 so combine the new args with the old. */
15158 }
15159 else
15160 {
15163 }
15164 }
15165 else
15166 {
15168 {
15170 args);
15172 }
15173 new_specs = tsubst_copy_and_build
15176 }
15178 /* We've instantiated a template before a noexcept-specifier
15179 contained therein has been parsed. This can happen for
15180 a nested template class:
15182 struct S {
15183 template<typename> struct B { B() noexcept(...); };
15184 struct A : B<int> { ... use B() ... };
15185 };
15187 where completing B<int> will trigger instantiating the
15188 noexcept, even though we only parse it at the end of S. */
15190 {
15193 }
15194 }
15196 {
15199 else
15201 {
15202 tree spec;
15207 {
15208 /* Expand the pack expansion type. */
15211 in_decl);
15217 else
15218 {
15219 /* We're substituting into a member template, so
15220 we got a TYPE_PACK_EXPANSION back. Add that
15221 expansion and move on. */
15225 expanded_specs,
15226 complain);
15229 }
15230 }
15233 {
15236 else
15241 complain);
15242 }
15245 }
15246 }
15248 }
15250 /* Substitute through a TREE_LIST of types or expressions, handling pack
15251 expansions. */
15253 tree
15255 {
15262 ;
15264 {
15268 }
15271 else
15279 ;
15281 {
15285 }
15288 else
15295 ;
15300 else
15311 /* Determine the number of arguments. */
15313 {
15316 }
15319 else
15323 {
15331 else
15333 }
15336 }
15338 /* Take the tree structure T and replace template parameters used
15339 therein with the argument vector ARGS. IN_DECL is an associated
15340 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
15341 Issue error and warning messages under control of COMPLAIN. Note
15342 that we must be relatively non-tolerant of extensions here, in
15343 order to preserve conformance; if we allow substitutions that
15344 should not be allowed, we may allow argument deductions that should
15345 not succeed, and therefore report ambiguous overload situations
15346 where there are none. In theory, we could allow the substitution,
15347 but indicate that it should have failed, and allow our caller to
15348 make sure that the right thing happens, but we don't try to do this
15349 yet.
15351 This function is used for dealing with types, decls and the like;
15352 for expressions, use tsubst_expr or tsubst_copy. */
15354 tree
15356 {
15382 /* Reuse typedefs. We need to do this to handle dependent attributes,
15383 such as attribute aligned. */
15386 {
15390 {
15391 /* DECL represents an alias template and we want to
15392 instantiate it. */
15396 }
15400 {
15404 }
15409 else
15410 /* The typedef is from a non-template context. */
15414 {
15416 r = cp_build_qualified_type_real
15420 }
15421 else
15422 {
15423 /* We don't have an instantiation yet, so drop the typedef. */
15428 }
15429 }
15446 {
15473 {
15479 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
15480 needed. */
15486 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
15487 with TREE_SIDE_EFFECTS that indicates this is not an integral
15488 constant expression. */
15491 {
15494 }
15497 }
15503 {
15517 {
15520 /* See through ARGUMENT_PACK_SELECT arguments. */
15523 }
15528 {
15530 /* If ARG is an argument pack, we don't actually want to
15531 perform a substitution here, because substitutions
15532 for argument packs are only done
15533 element-by-element. We can get to this point when
15534 substituting the type of a non-type template
15535 parameter pack, when that type actually contains
15536 template parameter packs from an outer template, e.g.,
15538 template<typename... Types> struct A {
15539 template<Types... Values> struct B { };
15540 }; */
15544 {
15547 /* When building concept checks for the purpose of
15548 deducing placeholders, we can end up with wildcards
15549 where types are expected. Adjust this to the deduced
15550 value. */
15558 return cp_build_qualified_type_real
15560 }
15562 {
15563 /* We are processing a type constructed from a
15564 template template parameter. */
15575 /* Consider this code:
15577 template <template <class> class Template>
15578 struct Internal {
15579 template <class Arg> using Bind = Template<Arg>;
15580 };
15582 template <template <class> class Template, class Arg>
15583 using Instantiate = Template<Arg>; //#0
15585 template <template <class> class Template,
15586 class Argument>
15587 using Bind =
15588 Instantiate<Internal<Template>::template Bind,
15589 Argument>; //#1
15591 When #1 is parsed, the
15592 BOUND_TEMPLATE_TEMPLATE_PARM representing the
15593 parameter `Template' in #0 matches the
15594 UNBOUND_CLASS_TEMPLATE representing the argument
15595 `Internal<Template>::template Bind'; We then want
15596 to assemble the type `Bind<Argument>' that can't
15597 be fully created right now, because
15598 `Internal<Template>' not being complete, the Bind
15599 template cannot be looked up in that context. So
15600 we need to "store" `Bind<Argument>' for later
15601 when the context of Bind becomes complete. Let's
15602 store that in a TYPENAME_TYPE. */
15606 argvec),
15607 typename_type,
15608 complain);
15610 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
15611 are resolving nested-types in the signature of a
15612 member function templates. Otherwise ARG is a
15613 TEMPLATE_DECL and is the real template to be
15614 instantiated. */
15622 complain);
15623 return cp_build_qualified_type_real
15625 }
15628 else
15629 /* TEMPLATE_PARM_INDEX. */
15631 }
15634 /* This can happen during the attempted tsubst'ing in
15635 unify. This means that we don't yet have any information
15636 about the template parameter in question. */
15639 /* Early in template argument deduction substitution, we don't
15640 want to reduce the level of 'auto', or it will be confused
15641 with a normal template parm in subsequent deduction.
15642 Similarly, don't reduce the level of template parameters to
15643 avoid mismatches when deducing their types. */
15647 /* If we get here, we must have been looking at a parm for a
15648 more deeply nested template. Make a new version of this
15649 template parameter, but with a lower level. */
15651 {
15656 {
15658 r = cp_build_qualified_type_real
15662 }
15669 /* Break infinite recursion when substituting the constraints
15678 /* Cache the simple case of lowering a type parameter. */
15680 else
15681 {
15692 {
15693 /* Propagate constraints on placeholders since they are
15694 only instantiated during satisfaction. */
15698 {
15703 }
15704 }
15707 /* We have reduced the level of the template
15708 template parameter, but not the levels of its
15709 template parameters, so canonical_type_parameter
15710 will not be able to find the canonical template
15711 template parameter for this level. Thus, we
15712 require structural equality checking to compare
15713 TEMPLATE_TEMPLATE_PARMs. */
15717 else
15721 {
15723 /* We might need to substitute into the types of non-type
15724 template parameters. */
15736 }
15737 }
15741 /* OK, now substitute the type of the non-type parameter. We
15742 couldn't do it earlier because it might be an auto parameter,
15743 and we wouldn't need to if we had an argument. */
15752 }
15755 }
15761 /* We should never be tsubsting a binfo. */
15765 /* A vector of template arguments. */
15771 {
15775 /* [temp.deduct]
15777 Type deduction may fail for any of the following
15778 reasons:
15780 -- Attempting to create a pointer to reference type.
15781 -- Attempting to create a reference to a reference type or
15782 a reference to void.
15784 Core issue 106 says that creating a reference to a reference
15785 during instantiation is no longer a cause for failure. We
15786 only enforce this check in strict C++98 mode. */
15790 {
15793 /* We keep track of the last time we issued this error
15794 message to avoid spewing a ton of messages during a
15795 single bad template instantiation. */
15798 {
15803 else
15806 }
15809 }
15813 {
15815 {
15818 type);
15819 else
15821 type);
15822 }
15824 }
15826 {
15830 }
15832 /* In C++0x, during template argument substitution, when there is an
15833 attempt to create a reference to a reference type, reference
15834 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
15836 "If a template-argument for a template-parameter T names a type
15837 that is a reference to a type A, an attempt to create the type
15838 'lvalue reference to cv T' creates the type 'lvalue reference to
15839 A,' while an attempt to create the type type rvalue reference to
15840 cv T' creates the type T"
15841 */
15842 r = cp_build_reference_type
15845 else
15850 /* Will this ever be needed for TYPE_..._TO values? */
15854 }
15856 {
15859 {
15860 /* [temp.deduct]
15862 Type deduction may fail for any of the following
15863 reasons:
15865 -- Attempting to create "pointer to member of T" when T
15866 is not a class type. */
15870 }
15872 {
15876 }
15878 {
15882 }
15885 {
15886 /* The type of the implicit object parameter gets its
15887 cv-qualifiers from the FUNCTION_TYPE. */
15888 tree memptr;
15889 tree method_type
15894 complain);
15895 }
15896 else
15899 complain);
15900 }
15903 {
15904 tree fntype;
15905 tree specs;
15910 /* Substitute the exception specification. */
15918 }
15920 {
15925 /* As an optimization, we avoid regenerating the array type if
15926 it will obviously be the same as T. */
15930 /* These checks should match the ones in create_array_type_for_decl.
15932 [temp.deduct]
15934 The deduction may fail for any of the following reasons:
15936 -- Attempting to create an array with an element type that
15937 is void, a function type, or a reference type, or [DR337]
15938 an abstract class type. */
15944 {
15948 }
15961 {
15964 }
15967 }
15970 {
15973 {
15979 {
15984 }
15986 }
15987 else
15999 {
16003 }
16005 {
16006 /* Normally, make_typename_type does not require that the CTX
16007 have complete type in order to allow things like:
16009 template <class T> struct S { typename S<T>::X Y; };
16011 But, such constructs have already been resolved by this
16012 point, so here CTX really should have complete type, unless
16013 it's a partial instantiation. */
16016 }
16023 {
16026 }
16029 {
16031 {
16035 else
16037 }
16039 {
16043 else
16045 }
16046 }
16048 return cp_build_qualified_type_real
16050 }
16053 {
16065 }
16068 {
16069 tree type;
16085 complain);
16086 }
16089 {
16090 tree type;
16109 else
16110 {
16114 /* In a template ~id could be either a complement expression
16115 or an unqualified-id naming a destructor; if instantiating
16116 it produces an expression, it's not an id-expression or
16117 member access. */
16120 }
16125 }
16128 {
16132 }
16151 /* We should use one of the expression tsubsts for these codes. */
16157 }
16158 }
16160 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
16161 expression on the left-hand side of the "." or "->" operator. We
16162 only do the lookup if we had a dependent BASELINK. Otherwise we
16163 adjust it onto the instantiated heirarchy. */
16165 static tree
16168 {
16180 {
16187 }
16194 {
16199 /* See maybe_dependent_member_ref. */
16201 {
16204 template_args);
16207 }
16210 /* Treat as-if non-dependent below. */
16214 complain);
16216 {
16222 }
16226 }
16227 else
16228 {
16229 /* We're going to overwrite pieces below, make a duplicate. */
16233 {
16234 /* The decl we found was from non-dependent scope, but we still need
16235 to update the binfos for the instantiated qualifying_scope. */
16239 }
16240 }
16242 /* If lookup found a single function, mark it as used at this point.
16243 (If lookup found multiple functions the one selected later by
16244 overload resolution will be marked as used at that point.) */
16246 {
16252 /* We might have instantiated an auto function. */
16254 }
16257 {
16258 /* Add back the template arguments, if present. */
16263 /* Update the conversion operator type. */
16265 }
16271 {
16273 qualifying_scope,
16274 object_type);
16276 /* We need to call adjust_result_of_qualified_name_lookup in case the
16277 destructor names a base class, but we unset BASELINK_QUALIFIED_P
16278 so that we still get virtual function binding. */
16280 }
16283 }
16285 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
16286 true if the qualified-id will be a postfix-expression in-and-of
16287 itself; false if more of the postfix-expression follows the
16288 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
16289 of "&". */
16291 static tree
16295 {
16296 tree expr;
16297 tree scope;
16298 tree name;
16300 tree template_args;
16305 /* Figure out what name to look up. */
16308 {
16317 }
16318 else
16319 {
16322 }
16324 /* Substitute into the qualifying scope. When there are no ARGS, we
16325 are just trying to simplify a non-dependent expression. In that
16326 case the qualifying scope may be dependent, and, in any case,
16327 substituting will not help. */
16330 {
16333 }
16334 else
16338 {
16345 }
16348 {
16350 {
16351 /* A BIT_NOT_EXPR is used to represent a destructor. */
16353 {
16357 }
16358 else
16361 }
16362 else
16366 {
16368 {
16372 }
16374 }
16375 }
16378 {
16382 /* Remember that there was a reference to this entity. */
16385 }
16388 {
16394 }
16397 {
16398 /* We may be repeating a check already done during parsing, but
16399 if it was well-formed and passed then, it will pass again
16400 now, and if it didn't, we wouldn't have got here. The case
16401 we want to catch is when we couldn't tell then, and can now,
16402 namely when templ prior to substitution was an
16403 identifier. */
16409 complain);
16410 else
16412 }
16418 {
16419 expr = (adjust_result_of_qualified_name_lookup
16421 expr = (finish_qualified_id_expr
16425 }
16427 /* Expressions do not generally have reference type. */
16429 /* However, if we're about to form a pointer-to-member, we just
16430 want the referenced member referenced. */
16440 }
16442 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
16443 initializer, DECL is the substituted VAR_DECL. Other arguments are as
16444 for tsubst. */
16446 static tree
16449 {
16458 {
16460 {
16462 {
16467 }
16468 }
16470 {
16471 /* If we had an initializer but it
16472 instantiated to nothing,
16473 value-initialize the object. This will
16474 only occur when the initializer was a
16475 pack expansion where the parameter packs
16476 used in that expansion were of length
16477 zero. */
16483 }
16484 }
16487 }
16489 /* If T is a reference to a dependent member of the current instantiation C and
16490 we are trying to refer to that member in a partial instantiation of C,
16491 return a SCOPE_REF; otherwise, return NULL_TREE.
16493 This can happen when forming a C++17 deduction guide, as in PR96199. */
16495 static tree
16497 tree in_decl)
16498 {
16512 }
16514 /* Like tsubst, but deals with expressions. This function just replaces
16515 template parms; to finish processing the resultant expression, use
16516 tsubst_copy_and_build or tsubst_expr. */
16518 static tree
16520 {
16522 tree r;
16530 {
16535 {
16536 /* We get here for a use of 'this' in an NSDMI. */
16540 /* This can happen for a parameter name used later in a function
16541 declaration (such as in a late-specified return type). Just
16542 make a dummy decl, since it's only used for its type. */
16545 /* Give it the template pattern as its context; its true context
16546 hasn't been instantiated yet and this is good enough for
16547 mangling. */
16549 }
16558 {
16559 tree enum_type;
16560 tree v;
16564 /* There is no need to substitute into namespace-scope
16565 enumerators. */
16568 /* If ARGS is NULL, then T is known to be non-dependent. */
16575 /* Unfortunately, we cannot just call lookup_name here.
16576 Consider:
16578 template <int I> int f() {
16579 enum E { a = I };
16580 struct S { void g() { E e = a; } };
16581 };
16583 When we instantiate f<7>::S::g(), say, lookup_name is not
16584 clever enough to find f<7>::a. */
16585 enum_type
16595 /* We didn't find the name. That should never happen; if
16596 name-lookup found it during preliminary parsing, we
16597 should find it again here during instantiation. */
16599 }
16604 {
16605 tree ctx;
16610 {
16613 {
16617 }
16619 }
16620 }
16632 {
16633 /* Local specialization will usually have been created when
16634 we instantiated the DECL_EXPR_DECL. */
16637 {
16638 /* We're in a generic lambda referencing a local extern
16639 from an outer block-scope of a non-template. */
16642 }
16643 }
16646 {
16649 {
16650 /* First try name lookup to find the instantiation. */
16653 {
16655 {
16656 /* During error-recovery we may find a non-variable,
16657 even an OVERLOAD: just bail out and avoid ICEs and
16658 duplicate diagnostics (c++/62207). */
16661 }
16663 {
16664 /* Make sure the one we found is the one we want. */
16668 }
16669 }
16673 else
16674 {
16675 /* This can happen for a variable used in a
16676 late-specified return type of a local lambda, or for a
16677 local static or constant. Building a new VAR_DECL
16678 should be OK in all those cases. */
16681 /* Avoid infinite recursion (79640). */
16684 {
16685 /* We can't call cp_finish_decl, so handle the
16686 initializer by hand. */
16701 }
16708 }
16709 /* Remember this for subsequent uses. */
16712 }
16715 }
16716 else
16740 {
16741 /* Template template argument like the following example need
16742 special treatment:
16744 template <template <class> class TT> struct C {};
16745 template <class T> struct D {
16746 template <class U> struct E {};
16747 C<E> c; // #1
16748 };
16749 D<int> d; // #2
16751 We are processing the template argument `E' in #1 for
16752 the template instantiation #2. Originally, `E' is a
16753 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
16754 have to substitute this with one having context `D<int>'. */
16758 {
16759 /* When rewriting a constructor into a deduction guide, a
16760 non-dependent name can become dependent, so memtmpl<args>
16761 becomes context::template memtmpl<args>. */
16765 }
16767 }
16768 else
16769 /* Ordinary template template argument. */
16774 {
16775 /* Handle location wrappers by substituting the wrapped node
16776 first, *then* reusing the resulting type. Doing the type
16777 first ensures that we handle template parameters and
16778 parameter pack expansions. */
16780 {
16784 }
16788 {
16789 /* Wrapper to make a C++20 template parameter object const. */
16792 {
16793 /* The template argument is not const, presumably because
16794 it is still dependent, and so not the const template parm
16795 object. */
16801 {
16802 /* Don't add a wrapper to these. */
16805 }
16806 else
16807 /* Do add a wrapper otherwise (in particular, if op is
16808 another TEMPLATE_PARM_INDEX). */
16810 }
16812 }
16813 /* force_paren_expr can also create a VIEW_CONVERT_EXPR. */
16815 {
16820 }
16821 /* We shouldn't see any other uses of these in templates. */
16823 }
16833 {
16837 }
16840 {
16846 }
16851 {
16860 /* We only want to compute the number of arguments. */
16863 else
16870 {
16872 /* Set TREE_USED for the benefit of -Wunused. */
16876 }
16884 {
16889 else
16897 else
16902 }
16903 else
16905 }
16907 {
16915 }
16916 /* Fall through */
16932 {
16939 }
16942 {
16943 tree object;
16944 tree name;
16949 {
16953 }
16956 {
16966 }
16971 in_decl);
16972 else
16975 }
17011 {
17015 }
17018 {
17023 }
17026 {
17030 }
17033 {
17041 }
17047 {
17054 }
17057 {
17064 }
17067 {
17074 }
17077 {
17078 /* Substituted template arguments */
17088 else
17090 }
17093 {
17113 }
17138 /* Fall through. */
17141 {
17144 }
17145 else
17149 /* This is handled by tsubst_copy_and_build. */
17153 {
17157 }
17160 /* We shouldn't have built any of these during initial template
17161 generation. Instead, they should be built during instantiation
17162 in response to the saved STMT_IS_FULL_EXPR_P setting. */
17166 {
17176 }
17193 {
17194 /* Instantiate any typedefs in the type. */
17199 }
17202 {
17206 {
17209 }
17211 }
17214 /* These can sometimes show up in a partial instantiation, but never
17215 involve template parms. */
17231 /* ??? There's no point in copying it for now, but maybe some
17232 day it will contain more information, such as a pointer back
17233 to the containing function, inlined copy or so. */
17242 /* We shouldn't get here, but keep going if !flag_checking. */
17246 }
17247 }
17249 /* Helper function for tsubst_omp_clauses, used for instantiation of
17250 OMP_CLAUSE_DECL of clauses. */
17252 static tree
17255 {
17259 /* Handle OpenMP iterators. */
17263 {
17264 tree ret;
17267 else
17268 {
17272 {
17287 }
17291 }
17295 }
17297 /* Handle an OpenMP array section represented as a TREE_LIST (or
17298 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
17299 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
17300 TREE_LIST. We can handle it exactly the same as an array section
17301 (purpose, value, and a chain), even though the nomenclature
17302 (low_bound, length, etc) is different. */
17304 {
17305 tree low_bound
17320 }
17323 /* Undo convert_from_reference tsubst_expr could have called. */
17329 }
17331 /* Like tsubst_copy, but specifically for OpenMP clauses. */
17333 static tree
17336 {
17342 {
17348 {
17351 {
17357 }
17358 /* FALLTHRU */
17415 {
17418 {
17425 }
17426 else
17428 }
17448 {
17451 }
17456 else
17459 in_decl,
17488 }
17491 {
17507 /* tsubst_expr on SCOPE_REF results in returning
17508 finish_non_static_data_member result. Undo that here. */
17512 {
17517 {
17521 CASE_CONVERT:
17530 /* FALLTHRU */
17534 }
17535 }
17541 {
17544 {
17547 }
17548 }
17552 }
17553 }
17557 {
17562 {
17565 }
17566 }
17568 }
17570 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
17572 static tree
17574 tree in_decl)
17575 {
17576 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
17596 {
17599 else
17600 {
17604 }
17605 }
17610 #undef RECUR
17611 }
17613 /* Used to temporarily communicate the list of #pragma omp parallel
17614 clauses to #pragma omp for instantiation if they are combined
17615 together. */
17622 /* Substitute one OMP_FOR iterator. */
17624 static bool
17629 {
17630 #define RECUR(NODE) \
17631 tsubst_expr ((NODE), args, complain, in_decl, \
17632 integral_constant_expression_p)
17644 {
17647 {
17652 {
17662 else
17664 {
17666 {
17672 }
17675 }
17676 }
17677 }
17681 }
17683 {
17684 /* We need to jump through some hoops to handle declarations in the
17685 init-statement, since we might need to handle auto deduction,
17686 but we need to keep control of initialization. */
17690 }
17691 else
17692 {
17694 {
17697 {
17701 {
17705 CASE_CONVERT:
17713 {
17716 }
17717 /* FALLTHRU */
17721 }
17722 }
17723 }
17724 else
17726 }
17728 {
17734 }
17735 else
17739 {
17745 NULL_TREE);
17746 else
17748 }
17751 {
17758 {
17763 }
17766 }
17776 {
17778 {
17779 /* Declare the variable, but don't let that initialize it. */
17784 }
17787 {
17791 {
17800 }
17801 else
17805 {
17810 }
17811 else
17815 }
17821 }
17824 {
17825 /* Declare and initialize the variable. */
17828 }
17830 {
17835 {
17837 {
17843 {
17846 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
17851 }
17854 {
17856 decl);
17858 }
17861 {
17863 decl);
17865 }
17866 else
17868 }
17871 }
17873 {
17876 ? OMP_CLAUSE_LASTPRIVATE
17881 {
17884 }
17885 }
17886 }
17889 {
17893 }
17894 else
17898 {
17909 {
17917 }
17918 else
17924 {
17930 }
17934 {
17942 }
17943 else
17949 }
17958 #undef RECUR
17959 }
17961 /* Helper function of tsubst_expr, find OMP_TEAMS inside
17962 of OMP_TARGET's body. */
17964 static tree
17966 {
17969 {
17978 }
17980 }
17982 /* Helper function for tsubst_expr. For decomposition declaration
17983 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
17984 also the corresponding decls representing the identifiers
17985 of the decomposition declaration. Return DECL if successful
17986 or error_mark_node otherwise, set *FIRST to the first decl
17987 in the list chained through DECL_CHAIN and *CNT to the number
17988 of such decls. */
17990 static tree
17994 {
17999 decl2
18004 {
18006 {
18009 }
18021 else
18022 {
18026 }
18033 {
18036 }
18037 else
18039 }
18042 }
18044 /* Return the proper local_specialization for init-capture pack DECL. */
18046 static tree
18048 {
18049 /* We handle normal pack captures by forwarding to the specialization of the
18050 captured parameter. We can't do that for pack init-captures; we need them
18051 to have their own local_specialization. We created the individual
18052 VAR_DECLs (if any) under build_capture_proxy, and we need to collect them
18053 when we process the DECL_EXPR for the pack init-capture in the template.
18054 So, how do we find them? We don't know the capture proxy pack when
18055 building the individual resulting proxies, and we don't know the
18056 individual proxies when instantiating the pack. What we have in common is
18057 the FIELD_DECL.
18059 So...when we instantiate the FIELD_DECL, we stick the result in
18060 local_specializations. Then at the DECL_EXPR we look up that result, see
18061 how many elements it has, synthesize the names, and look them up. */
18075 {
18080 }
18082 {
18087 else
18089 }
18091 }
18093 /* Like tsubst_copy for expressions, etc. but also does semantic
18094 processing. */
18096 tree
18099 {
18100 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
18101 #define RECUR(NODE) \
18102 tsubst_expr ((NODE), args, complain, in_decl, \
18103 integral_constant_expression_p)
18106 tree r;
18107 location_t loc;
18119 {
18121 {
18125 }
18156 else
18165 {
18167 tree init;
18173 {
18176 {
18180 {
18185 }
18187 }
18188 else
18189 {
18190 /* This is a non-dependent using-decl, and we'll have
18191 used the names it found during template parsing. We do
18192 not want to do the lookup again, because we might not
18193 find the things we found then. */
18196 /* We still need to push the bindings so that we can look up
18197 this name later. */
18200 }
18201 }
18204 {
18205 /* We're in tsubst_lambda_expr, we've already inserted a new
18206 capture proxy, so look it up and register it. */
18207 tree inst;
18209 {
18213 }
18215 {
18216 inst = (retrieve_local_specialization
18220 }
18221 else
18226 }
18233 /* Don't copy the old closure; we'll create a new one in
18234 tsubst_lambda_expr. */
18236 else
18237 {
18241 {
18242 /* By marking the declaration as instantiated, we avoid
18243 trying to instantiate it. Since instantiate_decl can't
18244 handle local variables, and since we've already done
18245 all that needs to be done, that's the right thing to
18246 do. */
18251 /* Anonymous aggregates are a special case. */
18254 {
18257 {
18261 }
18263 }
18268 {
18276 }
18277 else
18278 {
18295 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
18301 /* In a non-template function, VLA type declarations are
18302 handled in grokdeclarator; for templates, handle them
18303 now. */
18307 {
18311 asmspec_tree
18315 }
18321 }
18322 }
18323 }
18326 }
18336 {
18340 }
18345 {
18346 /* Construct another range_for, if this is not a final
18347 substitution (for inside a generic lambda of a
18348 template). Otherwise convert to a regular for. */
18350 stmt = (processing_template_decl
18367 {
18373 }
18374 else
18375 {
18381 }
18387 }
18394 {
18398 }
18404 {
18408 }
18424 {
18425 /* We're partially instantiating a generic lambda, but the condition
18426 of the constexpr if is still dependent. Don't substitute into the
18427 branches now, just remember the template arguments. */
18435 }
18439 {
18444 }
18445 else
18446 {
18454 }
18460 {
18470 }
18478 else
18486 else
18507 {
18513 {
18518 }
18519 }
18523 {
18525 tree label;
18532 }
18538 /* Computed goto's must be tsubst'd into. On the other hand,
18539 non-computed gotos must not be; the identifier in question
18540 will have no binding. */
18542 else
18548 {
18565 }
18570 {
18575 }
18576 else
18577 {
18582 else
18589 else
18595 else
18597 }
18601 {
18605 {
18607 /* Prevent instantiate_decl from trying to instantiate
18608 this variable. We've already done all that needs to be
18609 done. */
18612 }
18617 }
18623 {
18624 /* Local classes are not independent templates; they are
18625 instantiated along with their containing function. And this
18626 way we don't have to deal with pushing out of one local class
18627 to instantiate a member of another local class. */
18628 /* Closures are handled by the LAMBDA_EXPR. */
18638 }
18642 {
18643 tree condition;
18646 condition =
18648 args,
18657 }
18664 in_decl);
18686 {
18693 }
18709 {
18723 in_decl);
18725 {
18732 }
18743 any_range_for
18747 integral_constant_expression_p);
18751 {
18760 }
18761 else
18766 else
18773 else
18774 {
18782 }
18785 t));
18787 }
18793 /* FALLTHRU */
18803 in_decl);
18805 {
18810 }
18811 else
18812 {
18816 }
18821 {
18823 "%<#pragma omp critical%> with %<hint%> clause requires "
18826 }
18837 {
18840 {
18845 }
18846 else
18847 {
18851 }
18853 }
18854 else
18856 OMP_CLAUSE_DEPEND_SOURCE,
18865 ? C_ORT_ACC
18879 {
18882 {
18883 /* For combined target teams, ensure the num_teams and
18884 thread_limit clause expressions are evaluated on the host,
18885 before entering the target construct. */
18886 tree c;
18892 {
18901 OMP_CLAUSE_FIRSTPRIVATE);
18905 }
18906 }
18907 }
18955 /* FALLTHRU */
18973 {
18978 {
18981 }
18987 }
18988 else
18989 {
18996 {
18999 }
19002 {
19007 {
19010 }
19016 }
19017 else
19018 {
19022 }
19025 }
19029 {
19035 {
19039 {
19044 }
19048 }
19049 else
19050 {
19055 }
19056 }
19060 {
19064 }
19077 /* If the first operand was a statement, we're done with it. */
19081 complain));
19098 integral_constant_expression_p));
19099 }
19102 out:
19105 #undef RECUR
19106 #undef RETURN
19107 }
19109 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
19110 function. For description of the body see comment above
19111 cp_parser_omp_declare_reduction_exprs. */
19113 static void
19115 {
19121 tree_stmt_iterator tsi;
19132 {
19139 /* tsubsting a local var_decl leaves DECL_CONTEXT null, as we
19140 expect to be pushing it. */
19152 }
19154 {
19174 }
19175 }
19177 /* T is a postfix-expression that is not being used in a function
19178 call. Return the substituted version of T. */
19180 static tree
19182 tsubst_flags_t complain,
19183 tree in_decl)
19184 {
19188 else
19194 }
19196 /* Subroutine of tsubst_lambda_expr: add the FIELD/INIT capture pair to the
19197 LAMBDA_EXPR_CAPTURE_LIST passed in LIST. Do deduction for a previously
19198 dependent init-capture. */
19200 static void
19202 tsubst_flags_t complain)
19203 {
19205 {
19208 {
19212 }
19219 }
19221 }
19223 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
19224 instantiation context. Instantiating a pack expansion containing a lambda
19225 might result in multiple lambdas all based on the same lambda in the
19226 template. */
19228 tree
19230 {
19244 else
19255 {
19260 else
19273 {
19274 /* For a VLA, simply tsubsting the field type won't work, we need to
19275 go through add_capture again. XXX do we want to do this for all
19276 captures? */
19277 tree name = (get_identifier
19285 }
19292 {
19293 /* Remember these for when we've pushed local_specializations. */
19296 }
19302 {
19310 complain);
19311 }
19312 else
19313 {
19315 complain);
19319 }
19320 }
19327 /* A lambda in a default argument outside a class gets no
19328 LAMBDA_EXPR_EXTRA_SCOPE, as specified by the ABI. But
19329 tsubst_default_argument calls start_lambda_scope, so we need to
19330 specifically ignore it here, and use the global scope. */
19332 else
19335 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
19353 else
19354 {
19355 /* The body of a lambda-expression is not a subexpression of the
19356 enclosing expression. Parms are to have DECL_CHAIN tsubsted,
19357 which would be skipped if cp_unevaluated_operand. */
19358 cp_evaluated ev;
19360 /* Fix the type of 'this'. */
19366 {
19369 {
19372 }
19375 }
19376 else
19377 {
19381 {
19384 }
19386 }
19388 /* Let finish_function set this. */
19394 else
19395 /* Still increment function_depth so that we don't GC in the
19396 middle of an expression. */
19406 /* Now record them for lookup_init_capture_pack. */
19409 {
19413 }
19419 {
19420 /* We might not partially instantiate some parts of the function, so
19421 copy these flags from the original template. */
19427 }
19429 /* [temp.deduct] A lambda-expression appearing in a function type or a
19430 template parameter is not considered part of the immediate context for
19431 the purposes of template argument deduction. */
19436 /* We already have a body block from start_lambda_function, we don't
19437 need another to confuse NRV (91217). */
19448 else
19451 /* The capture list was built up in reverse order; fix that now. */
19458 }
19460 out:
19466 }
19468 /* Like tsubst but deals with expressions and performs semantic
19469 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)" or
19470 "F<TARGS> (ARGS)". */
19472 tree
19474 tree args,
19475 tsubst_flags_t complain,
19476 tree in_decl,
19479 {
19480 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
19481 #define RECUR(NODE) \
19482 tsubst_copy_and_build (NODE, args, complain, in_decl, \
19484 integral_constant_expression_p)
19487 location_t save_loc;
19496 /* N3276 decltype magic only applies to calls at the top level or on the
19497 right side of a comma. */
19502 {
19505 /* Fall through. */
19507 {
19508 tree decl;
19509 cp_id_kind idk;
19514 {
19517 }
19519 /* Look up the name. */
19522 /* By convention, expressions use ERROR_MARK_NODE to indicate
19523 failure, not NULL_TREE. */
19529 integral_constant_expression_p,
19537 input_location);
19541 {
19545 }
19547 }
19550 {
19551 tree object;
19554 function_p,
19555 integral_constant_expression_p);
19564 {
19569 }
19572 {
19579 /* If we built a function concept check, return the underlying
19580 template-id. So we can evaluate it as a function call. */
19585 }
19588 {
19590 complain);
19593 }
19596 {
19599 }
19600 else
19609 {
19610 /* C++20 P0846: we can encounter an IDENTIFIER_NODE here when
19611 name lookup found nothing when parsing the template name. */
19614 }
19615 else
19617 }
19620 {
19624 {
19625 /* A type conversion to reference type will be enclosed in
19626 such an indirect ref, but the substitution of the cast
19627 will have also added such an indirect ref. */
19629 }
19630 else
19638 }
19641 {
19645 }
19648 {
19652 {
19657 }
19659 /* We'll pass this to convert_nontype_argument again, we don't need
19660 to actually perform any conversion here. */
19668 flags));
19669 }
19672 {
19678 }
19685 {
19686 tree type;
19692 {
19697 }
19705 {
19725 }
19728 }
19731 {
19735 }
19758 /* convert_like should have created an IMPLICIT_CONV_EXPR. */
19769 else
19771 in_decl);
19805 {
19806 /* If either OP0 or OP1 was value- or type-dependent, suppress
19807 warnings that depend on the range of the types involved. */
19817 };
19827 tree r = build_x_binary_op
19829 op0,
19831 ? ERROR_MARK
19833 op1,
19835 ? ERROR_MARK
19843 }
19846 {
19854 }
19875 /* Fall through */
19878 {
19879 tree r;
19887 {
19888 /* When there are no ARGS, we are trying to evaluate a
19889 non-dependent expression from the parser. Trying to do
19890 the substitutions may not work. */
19893 }
19894 else
19895 {
19900 else
19903 /*integral_constant_expression_p=*/
19907 }
19912 else
19917 {
19919 {
19921 {
19925 }
19926 else
19930 }
19932 }
19934 }
19937 {
19947 }
19963 {
19967 tree r = build_x_modify_expr
19970 /* TREE_NO_WARNING must be set if either the expression was
19971 parenthesized or it uses an operator such as >>= rather
19972 than plain assignment. In the former case, it was already
19973 set and must be copied. In the latter case,
19974 build_x_modify_expr sets it and it must not be reset
19975 here. */
19980 }
19985 /* Remember that there was a reference to this entity. */
19992 {
19997 tree ret;
20004 else
20005 {
20009 }
20011 /* If there was an initializer in the original tree, but it
20012 instantiated to an empty list, then we should pass a
20013 non-NULL empty vector to tell build_new that it was an
20014 empty initializer() rather than no initializer. This can
20015 only happen when the initializer is a pack expansion whose
20016 parameter packs are of length zero. */
20021 else
20022 {
20026 else
20027 {
20030 }
20031 }
20033 /* Avoid passing an enclosing decl to valid_array_size_p. */
20040 complain);
20048 }
20051 {
20057 complain));
20058 }
20061 {
20065 integral_constant_expression_p);
20067 op0,
20070 }
20073 {
20074 tree function;
20078 tree ret;
20081 /* Internal function with no arguments. */
20085 /* When we parsed the expression, we determined whether or
20086 not Koenig lookup should be performed. */
20089 {
20092 }
20094 {
20099 }
20101 {
20102 /* Do nothing; calling tsubst_copy_and_build on an identifier
20103 would incorrectly perform unqualified lookup again.
20105 Note that we can also have an IDENTIFIER_NODE if the earlier
20106 unqualified lookup found a member function; in that case
20107 koenig_p will be false and we do want to do the lookup
20108 again to find the instantiated member function.
20110 FIXME but doing that causes c++/15272, so we need to stop
20111 using IDENTIFIER_NODE in that situation. */
20113 }
20114 else
20115 {
20117 {
20123 }
20124 else
20129 /* Avoid error about taking the address of a constructor. */
20134 /* When KOENIG_P, we don't want to mark_used the callee before
20135 augmenting the overload set via ADL, so during this initial
20136 substitution we disable mark_used by setting tf_conv (68942). */
20139 in_decl,
20141 integral_constant_expression_p);
20145 }
20148 releasing_vec call_args;
20150 {
20155 else
20156 {
20157 /* Expand the pack expansion and push each entry onto
20158 CALL_ARGS. */
20161 {
20166 {
20171 }
20172 }
20173 else
20174 {
20175 /* A partial substitution. Add one entry. */
20177 }
20178 }
20179 }
20181 /* Stripped-down processing for a call in a thunk. Specifically, in
20182 the thunk template for a generic lambda. */
20184 {
20185 /* Now that we've expanded any packs, the number of call args
20186 might be different. */
20190 {
20197 }
20198 /* We aren't going to do normal overload resolution, so force the
20199 template-id to resolve. */
20202 {
20203 /* In a thunk, pass through args directly, without any
20204 conversions. */
20209 }
20211 {
20212 /* If there are no other args, just push 'this'. */
20215 else
20216 {
20217 /* Otherwise, shift the other args over to make room. */
20223 }
20224 }
20227 /* The thunk location is not interesting. */
20234 }
20236 /* We do not perform argument-dependent lookup if normal
20237 lookup finds a non-function, in accordance with the
20238 resolution of DR 218. */
20241 /* If lookup found a member function, the Koenig lookup is
20242 not appropriate, even if an unqualified-name was used
20243 to denote the function. */
20246 /* C++20 P0846: Lookup found nothing. */
20249 /* Only do this when substitution turns a dependent call
20250 into a non-dependent call. */
20260 {
20264 {
20265 /* For backwards compatibility and good diagnostics, try
20266 the unqualified lookup again if we aren't in SFINAE
20267 context. */
20268 tree unq = (tsubst_copy_and_build
20270 integral_constant_expression_p));
20275 {
20276 /* In a lambda fn, we have to be careful to not
20277 introduce new this captures. Legacy code can't
20278 be using lambdas anyway, so it's ok to be
20279 stricter. */
20284 "and no declarations were found by "
20285 "argument-dependent lookup at the point "
20292 else
20296 {
20307 {
20310 "declarations in dependent base %qT are "
20316 else
20320 }
20321 else
20323 "%qD declared here, later in the "
20327 }
20330 }
20331 }
20333 {
20337 }
20338 }
20340 /* Remember that there was a reference to this entity. */
20346 /* Put back tf_decltype for the actual call. */
20351 {
20355 {
20357 "wrong number of arguments to "
20360 }
20361 else
20369 {
20371 "wrong number of arguments to "
20375 }
20379 complain);
20385 {
20387 complain);
20391 }
20394 /* Unsupported internal function with arguments. */
20396 }
20401 complain);
20403 {
20418 complain);
20419 else
20420 ret = (build_new_method_call
20425 complain));
20426 }
20428 {
20429 /* FUNCTION is a template-id referring to a concept definition. */
20434 /* Calls to standard and variable concepts should have been
20435 previously diagnosed. */
20438 /* Ensure the result is wrapped as a call expression. */
20440 }
20441 else
20444 koenig_p,
20445 complain);
20448 {
20453 {
20458 }
20459 }
20462 }
20465 {
20472 {
20474 {
20479 }
20480 else
20481 {
20486 }
20488 }
20489 else
20490 {
20493 }
20498 }
20501 {
20506 input_location));
20507 }
20513 {
20514 tree object;
20515 tree object_type;
20516 tree member;
20517 tree r;
20521 /* Remember that there was a reference to this entity. */
20532 else
20539 {
20542 }
20544 {
20549 }
20553 {
20555 {
20560 {
20563 }
20565 {
20570 }
20571 }
20572 }
20575 {
20576 /* Lookup the template functions now that we know what the
20577 scope is. */
20584 {
20587 args);
20588 member = (adjust_result_of_qualified_name_lookup
20590 object_type));
20591 }
20592 else
20593 {
20595 input_location);
20597 }
20598 }
20602 {
20604 {
20608 else
20611 }
20613 }
20617 complain);
20621 }
20628 {
20636 tree r;
20641 /* We do not want to process the index of aggregate
20642 initializers as they are identifier nodes which will be
20643 looked up by digest_init. */
20647 {
20650 }
20655 {
20657 /* An identifier index is looked up in the type
20658 being initialized, not the current scope. */
20663 {
20664 /* Substitute into the pack expansion. */
20666 in_decl);
20670 ;
20672 /* Just move the argument into place. */
20674 else
20675 {
20676 /* Update the length of the final CONSTRUCTOR
20677 arguments vector, and note that we will need to
20678 copy.*/
20681 }
20682 }
20683 else
20685 }
20688 {
20693 {
20695 {
20700 }
20701 else
20703 }
20704 }
20712 {
20717 }
20721 }
20724 {
20727 {
20730 }
20731 else
20732 {
20735 }
20736 }
20741 /* Fall through */
20744 {
20746 /* ??? We're doing a subset of finish_id_expression here. */
20748 /* Replace an evaluated use of the thread_local variable with
20749 a call to its wrapper. */
20755 /* If the original type was a reference, we'll be wrapped in
20756 the appropriate INDIRECT_REF. */
20759 }
20762 {
20766 }
20769 {
20770 tree object_ptr
20777 }
20784 {
20791 }
20794 {
20800 integral_constant_expression_p);
20804 /* If the resulting list of expression statement is empty,
20805 fold it further into void_node. */
20810 }
20813 {
20815 {
20816 /* We don't have a full set of template arguments yet; don't touch
20817 the lambda at all. */
20820 }
20824 }
20827 /* We can get here for a constant initializer of non-dependent type.
20828 FIXME stop folding in cp_parser_initializer_clause. */
20829 {
20831 complain);
20833 }
20837 integral_constant_expression_p));
20843 {
20848 complain));
20849 }
20852 {
20855 }
20858 /* No need to substitute further, a RANGE_EXPR will always be built
20859 with constant operands. */
20865 /* We need to do this here as well as in tsubst_copy so we get the
20866 other tsubst_copy_and_build semantics for a PARM_DECL operand. */
20869 /* fallthrough. */
20872 /* Handle Objective-C++ constructs, if appropriate. */
20873 {
20874 tree subst
20879 }
20881 }
20883 #undef RECUR
20884 #undef RETURN
20885 out:
20888 }
20890 /* Verify that the instantiated ARGS are valid. For type arguments,
20891 make sure that the type's linkage is ok. For non-type arguments,
20892 make sure they are constants if they are integral or enumerations.
20893 Emit an error under control of COMPLAIN, and return TRUE on error. */
20895 static bool
20897 {
20901 {
20911 }
20913 {
20914 /* [basic.link]: A name with no linkage (notably, the name
20915 of a class or enumeration declared in a local scope)
20916 shall not be used to declare an entity with linkage.
20917 This implies that names with no linkage cannot be used as
20918 template arguments
20920 DR 757 relaxes this restriction for C++0x. */
20925 {
20926 /* DR 488 makes use of a type with no linkage cause
20927 type deduction to fail. */
20929 {
20932 else
20935 }
20937 }
20938 /* In order to avoid all sorts of complications, we do not
20939 allow variably-modified types as template arguments. */
20941 {
20945 }
20946 }
20947 /* Class template and alias template arguments should be OK. */
20949 ;
20950 /* A non-type argument of integral or enumerated type must be a
20951 constant. */
20956 {
20960 }
20962 }
20964 static bool
20966 {
20971 {
20974 }
20978 }
20980 /* We're out of SFINAE context now, so generate diagnostics for the access
20981 errors we saw earlier when instantiating D from TMPL and ARGS. */
20983 static void
20985 {
20997 }
20999 /* Instantiate the indicated variable, function, or alias template TMPL with
21000 the template arguments in TARG_PTR. */
21002 static tree
21004 {
21006 tree fndecl;
21007 tree gen_tmpl;
21008 tree spec;
21019 /* If this function is a clone, handle it specially. */
21021 {
21022 tree spec;
21023 tree clone;
21025 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
21026 DECL_CLONED_FUNCTION. */
21032 /* Look for the clone. */
21036 /* We should always have found the clone by now. */
21039 }
21044 /* Check to see if we already have this specialization. */
21048 /* targ_ptr only has the innermost template args, so add the outer ones
21049 from tmpl, which could be either a partial instantiation or gen_tmpl (in
21050 the case of a non-dependent call within a template definition). */
21051 targ_ptr = (add_outermost_template_args
21053 targ_ptr));
21055 /* It would be nice to avoid hashing here and then again in tsubst_decl,
21056 but it doesn't seem to be on the hot path. */
21060 || ((fndecl
21066 {
21068 {
21072 }
21074 }
21077 complain))
21080 /* We are building a FUNCTION_DECL, during which the access of its
21081 parameters and return types have to be checked. However this
21082 FUNCTION_DECL which is the desired context for access checking
21083 is not built yet. We solve this chicken-and-egg problem by
21084 deferring all checks until we have the FUNCTION_DECL. */
21087 /* Instantiation of the function happens in the context of the function
21088 template, not the context of the overload resolution we're doing. */
21090 /* If there are dependent arguments, e.g. because we're doing partial
21091 ordering, make sure processing_template_decl stays set. */
21095 {
21099 }
21105 {
21106 /* We need to determine if we're using a partial or explicit
21107 specialization now, because the type of the variable could be
21108 different. */
21114 {
21119 }
21120 }
21122 /* Substitute template parameters to obtain the specialization. */
21130 {
21133 }
21135 /* The DECL_TI_TEMPLATE should always be the immediate parent
21136 template, not the most general template. */
21142 /* Now we know the specialization, compute access previously
21143 deferred. Do no access control for inheriting constructors,
21144 as we already checked access for the inherited constructor. */
21147 {
21152 }
21155 /* If we've just instantiated the main entry point for a function,
21156 instantiate all the alternate entry points as well. We do this
21157 by cloning the instantiation of the main entry point, not by
21158 instantiating the template clones. */
21164 {
21166 {
21167 /* Remember to reinstantiate when we're out of SFINAE so the user
21168 can see the errors. */
21170 }
21172 }
21174 }
21176 /* Wrapper for instantiate_template_1. */
21178 tree
21180 {
21181 tree ret;
21186 }
21188 /* Instantiate the alias template TMPL with ARGS. Also push a template
21189 instantiation level, which instantiate_template doesn't do because
21190 functions and variables have sufficient context established by the
21191 callers. */
21193 static tree
21195 {
21199 args =
21205 /* FIXME check for satisfaction in check_instantiated_args. */
21209 {
21211 {
21212 auto_diagnostic_group d;
21215 }
21217 }
21225 {
21226 /* An alias template specialization can be dependent
21227 even if its underlying type is not. */
21230 /* Sometimes a dependent alias spec is equivalent to its expansion,
21231 sometimes not. So always use structural_comptypes. */
21233 }
21236 }
21238 /* PARM is a template parameter pack for FN. Returns true iff
21239 PARM is used in a deducible way in the argument list of FN. */
21241 static bool
21243 {
21246 {
21248 tree packs;
21254 {
21255 /* The template parameter pack is used in a function parameter
21256 pack. If this is the end of the parameter list, the
21257 template parameter pack is deducible. */
21260 else
21261 /* Otherwise, not. Well, it could be deduced from
21262 a non-pack parameter, but doing so would end up with
21263 a deduction mismatch, so don't bother. */
21265 }
21266 }
21267 /* The template parameter pack isn't used in any function parameter
21268 packs, but it might be used deeper, e.g. tuple<Args...>. */
21270 }
21272 /* Subroutine of fn_type_unification: check non-dependent parms for
21273 convertibility. */
21275 static int
21279 {
21280 /* Non-constructor methods need to leave a conversion for 'this', which
21281 isn't included in nargs here. */
21287 {
21293 /* For a function parameter pack that occurs at the end of the
21294 parameter-declaration-list, the type A of each remaining
21295 argument of the call is compared with the type P of the
21296 declarator-id of the function parameter pack. */
21302 /* For a function parameter pack that does not occur at the
21303 end of the parameter-declaration-list, the type of the
21304 parameter pack is a non-deduced context. */
21308 {
21316 }
21319 }
21322 }
21324 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
21325 NARGS elements of the arguments that are being used when calling
21326 it. TARGS is a vector into which the deduced template arguments
21327 are placed.
21329 Returns either a FUNCTION_DECL for the matching specialization of FN or
21330 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
21331 true, diagnostics will be printed to explain why it failed.
21333 If FN is a conversion operator, or we are trying to produce a specific
21334 specialization, RETURN_TYPE is the return type desired.
21336 The EXPLICIT_TARGS are explicit template arguments provided via a
21337 template-id.
21339 The parameter STRICT is one of:
21341 DEDUCE_CALL:
21342 We are deducing arguments for a function call, as in
21343 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
21344 deducing arguments for a call to the result of a conversion
21345 function template, as in [over.call.object].
21347 DEDUCE_CONV:
21348 We are deducing arguments for a conversion function, as in
21349 [temp.deduct.conv].
21351 DEDUCE_EXACT:
21352 We are deducing arguments when doing an explicit instantiation
21353 as in [temp.explicit], when determining an explicit specialization
21354 as in [temp.expl.spec], or when taking the address of a function
21355 template, as in [temp.deduct.funcaddr]. */
21357 tree
21359 tree explicit_targs,
21360 tree targs,
21363 tree return_type,
21364 unification_kind_t strict,
21369 {
21370 tree parms;
21371 tree fntype;
21376 /* type_unification_real will pass back any access checks from default
21377 template argument substitution. */
21379 /* We don't have all the template args yet. */
21392 full_targs = (add_outermost_template_args
21394 targs));
21399 /* In C++0x, it's possible to have a function template whose type depends
21400 on itself recursively. This is most obvious with decltype, but can also
21401 occur with enumeration scope (c++/48969). So we need to catch infinite
21402 recursion and reject the substitution at deduction time; this function
21403 will return error_mark_node for any repeated substitution.
21405 This also catches excessive recursion such as when f<N> depends on
21406 f<N-1> across all integers, and returns error_mark_node for all the
21407 substitutions back up to the initial one.
21409 This is, of course, not reentrant. */
21418 {
21419 /* [temp.deduct]
21421 The specified template arguments must match the template
21422 parameters in kind (i.e., type, nontype, template), and there
21423 must not be more arguments than there are parameters;
21424 otherwise type deduction fails.
21426 Nontype arguments must match the types of the corresponding
21427 nontype template parameters, or must be convertible to the
21428 types of the corresponding nontype parameters as specified in
21429 _temp.arg.nontype_, otherwise type deduction fails.
21431 All references in the function type of the function template
21432 to the corresponding template parameters are replaced by the
21433 specified template argument values. If a substitution in a
21434 template parameter or in the function type of the function
21435 template results in an invalid type, type deduction fails. */
21446 explicit_targs);
21448 /* Adjust any explicit template arguments before entering the
21449 substitution context. */
21450 explicit_targs
21458 /* Substitute the explicit args into the function type. This is
21459 necessary so that, for instance, explicitly declared function
21460 arguments can match null pointed constants. If we were given
21461 an incomplete set of explicit args, we must not do semantic
21462 processing during substitution as we could create partial
21463 instantiations. */
21465 {
21470 /* Dig out the actual parm. */
21473 {
21476 }
21478 {
21481 }
21484 /* No explicit argument for this template parameter. */
21487 {
21488 /* Mark the argument pack as "incomplete". We could
21489 still deduce more arguments during unification.
21490 We remove this mark in type_unification_real. */
21495 /* We have some incomplete argument packs. */
21497 }
21498 }
21501 {
21503 {
21506 }
21509 /* Ignore any access checks; we'll see them again in
21510 instantiate_template and they might have the wrong
21511 access path at this point. */
21522 }
21524 /* Place the explicitly specified arguments in TARGS. */
21530 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
21532 }
21535 {
21541 }
21546 /* Never do unification on the 'this' parameter. */
21550 {
21551 /* We're deducing for a call to the result of a template conversion
21552 function. The parms we really want are in return_type. */
21556 }
21558 {
21560 }
21562 /* We allow incomplete unification without an error message here
21563 because the standard doesn't seem to explicitly prohibit it. Our
21564 callers must be ready to deal with unification failures in any
21565 event. */
21567 /* If we aren't explaining yet, push tinst context so we can see where
21568 any errors (e.g. from class instantiations triggered by instantiation
21569 of default template arguments) come from. If we are explaining, this
21570 context is redundant. */
21572 {
21575 }
21585 /* Now that we have bindings for all of the template arguments,
21586 ensure that the arguments deduced for the template template
21587 parameters have compatible template parameter lists. We cannot
21588 check this property before we have deduced all template
21589 arguments, because the template parameter types of a template
21590 template parameter might depend on prior template parameters
21591 deduced after the template template parameter. The following
21592 ill-formed example illustrates this issue:
21594 template<typename T, template<T> class C> void f(C<5>, T);
21596 template<int N> struct X {};
21598 void g() {
21599 f(X<5>(), 5l); // error: template argument deduction fails
21600 }
21602 The template parameter list of 'C' depends on the template type
21603 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
21604 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
21605 time that we deduce 'C'. */
21608 {
21611 }
21613 deduced:
21615 /* CWG2369: Check satisfaction before non-deducible conversions. */
21617 {
21621 }
21623 /* DR 1391: All parameters have args, now check non-dependent parms for
21624 convertibility. We don't do this if all args were explicitly specified,
21625 as the standard says that we substitute explicit args immediately. */
21631 /* All is well so far. Now, check:
21633 [temp.deduct]
21635 When all template arguments have been deduced, all uses of
21636 template parameters in nondeduced contexts are replaced with
21637 the corresponding deduced argument values. If the
21638 substitution results in an invalid type, as described above,
21639 type deduction fails. */
21641 {
21644 }
21646 /* Also collect access checks from the instantiation. */
21659 /* Now perform any access checks encountered during substitution. */
21666 /* If we're looking for an exact match, check that what we got
21667 is indeed an exact match. It might not be if some template
21668 parameters are used in non-deduced contexts. But don't check
21669 for an exact match if we have dependent template arguments;
21670 in that case we're doing partial ordering, and we already know
21671 that we have two candidates that will provide the actual type. */
21673 {
21677 tree sarg
21683 {
21687 }
21688 }
21690 /* After doing deduction with the inherited constructor, actually return an
21691 instantiation of the inheriting constructor. */
21697 fail:
21700 {
21702 /* Reset once we're all the way out. */
21704 }
21707 }
21709 /* Returns true iff PARM is a forwarding reference in the context of
21710 template argument deduction for TMPL. */
21712 static bool
21714 {
21715 /* [temp.deduct.call], "A forwarding reference is an rvalue reference to a
21716 cv-unqualified template parameter ..." */
21721 {
21723 /* [temp.deduct.call], "... that does not represent a template parameter
21724 of a class template (during class template argument deduction)." */
21728 {
21729 /* Since the template parameters of a synthesized guide consist of
21730 the template parameters of the class template followed by those of
21731 the constructor (if any), we can tell if PARM represents a template
21732 parameter of the class template by comparing its index with the
21733 arity of the class template. */
21738 }
21740 }
21742 }
21744 /* Adjust types before performing type deduction, as described in
21745 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
21746 sections are symmetric. PARM is the type of a function parameter
21747 or the return type of the conversion function. ARG is the type of
21748 the argument passed to the call, or the type of the value
21749 initialized with the result of the conversion function.
21750 ARG_EXPR is the original argument expression, which may be null. */
21752 static int
21754 unification_kind_t strict,
21757 tree arg_expr)
21758 {
21762 {
21767 /* Swap PARM and ARG throughout the remainder of this
21768 function; the handling is precisely symmetric since PARM
21769 will initialize ARG rather than vice versa. */
21774 /* Core issue #873: Do the DR606 thing (see below) for these cases,
21775 too, but here handle it by stripping the reference from PARM
21776 rather than by adding it to ARG. */
21781 /* Nothing else to do in this case. */
21786 }
21789 {
21790 /* [temp.deduct.call]
21792 If P is not a reference type:
21794 --If A is an array type, the pointer type produced by the
21795 array-to-pointer standard conversion (_conv.array_) is
21796 used in place of A for type deduction; otherwise,
21798 --If A is a function type, the pointer type produced by
21799 the function-to-pointer standard conversion
21800 (_conv.func_) is used in place of A for type deduction;
21801 otherwise,
21803 --If A is a cv-qualified type, the top level
21804 cv-qualifiers of A's type are ignored for type
21805 deduction. */
21810 else
21812 }
21814 /* [temp.deduct.call], "If P is a forwarding reference and the argument is
21815 an lvalue, the type 'lvalue reference to A' is used in place of A for
21816 type deduction." */
21819 /* try_one_overload doesn't provide an arg_expr, but
21820 functions are always lvalues. */
21824 /* [temp.deduct.call]
21826 If P is a cv-qualified type, the top level cv-qualifiers
21827 of P's type are ignored for type deduction. If P is a
21828 reference type, the type referred to by P is used for
21829 type deduction. */
21832 {
21835 }
21837 /* DR 322. For conversion deduction, remove a reference type on parm
21838 too (which has been swapped into ARG). */
21843 }
21845 /* Subroutine of fn_type_unification. PARM is a function parameter of a
21846 template which doesn't contain any deducible template parameters; check if
21847 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
21848 unify_one_argument. */
21850 static int
21854 {
21855 tree type;
21859 else
21867 {
21870 }
21872 {
21876 /* Avoid recalculating this in add_function_candidate. */
21877 ok = (*conv_p
21879 else
21883 }
21887 else
21889 }
21893 /* Returns true iff the expression EXPR is one from which a template
21894 argument can be deduced. In other words, if it's an undecorated
21895 use of a template non-type parameter. */
21897 static bool
21899 {
21900 /* Strip implicit conversions and implicit INDIRECT_REFs. */
21906 }
21908 /* Returns true iff the array domain DOMAIN uses a template parameter in a
21909 deducible way; that is, if it has a max value of <PARM> - 1. */
21911 static bool
21913 {
21922 }
21924 /* Returns true iff the template arguments ARGS use a template parameter
21925 in a deducible way. */
21927 static bool
21929 {
21931 {
21936 else
21937 {
21944 else
21946 }
21949 }
21951 }
21953 /* Returns true iff TYPE contains any deducible references to template
21954 parameters, as per 14.8.2.5. */
21956 static bool
21958 {
21962 /* T
21963 cv-list T
21964 TT<T>
21965 TT<i>
21966 TT<> */
21971 /* T*
21972 T&
21973 T&& */
21977 /* T[integer-constant ]
21978 type [i] */
21983 /* T type ::*
21984 type T::*
21985 T T::*
21986 T (type ::*)()
21987 type (T::*)()
21988 type (type ::*)(T)
21989 type (T::*)(T)
21990 T (type ::*)(T)
21991 T (T::*)()
21992 T (T::*)(T) */
21995 || (uses_deducible_template_parms
21998 /* template-name <T> (where template-name refers to a class template)
21999 template-name <i> (where template-name refers to a class template) */
22006 /* type (T)
22007 T()
22008 T(T) */
22010 {
22019 }
22022 }
22024 /* Subroutine of type_unification_real and unify_pack_expansion to
22025 handle unification of a single P/A pair. Parameters are as
22026 for those functions. */
22028 static int
22032 {
22039 /* We can't deduce anything from this, but we might get all the
22040 template args from other function args. */
22043 /* Implicit conversions (Clause 4) will be performed on a function
22044 argument to convert it to the type of the corresponding function
22045 parameter if the parameter type contains no template-parameters that
22046 participate in template argument deduction. */
22049 /* For function parameters with no deducible template parameters,
22050 just return. We'll check non-dependent conversions later. */
22054 {
22056 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
22057 | UNIFY_ALLOW_MORE_CV_QUAL
22071 }
22073 /* We only do these transformations if this is the top-level
22074 parameter_type_list in a call or declaration matching; in other
22075 situations (nested function declarators, template argument lists) we
22076 won't be comparing a type to an expression, and we don't do any type
22077 adjustments. */
22079 {
22081 {
22084 {
22085 /* [temp.deduct.type] A template-argument can be
22086 deduced from a pointer to function or pointer
22087 to member function argument if the set of
22088 overloaded functions does not contain function
22089 templates and at most one of a set of
22090 overloaded functions provides a unique
22091 match. */
22095 /* If a unique match was not found, this is a
22096 non-deduced context, so we still succeed. */
22098 }
22104 }
22108 }
22109 else
22114 /* For deduction from an init-list we need the actual list. */
22118 }
22120 /* for_each_template_parm callback that always returns 0. */
22122 static int
22124 {
22126 }
22128 /* for_each_template_parm any_fn callback to handle deduction of a template
22129 type argument from the type of an array bound. */
22131 static int
22133 {
22141 {
22147 }
22149 /* Keep walking. */
22151 }
22153 /* Try to deduce any not-yet-deduced template type arguments from the type of
22154 an array bound. This is handled separately from unify because 14.8.2.5 says
22155 "The type of a type parameter is only deduced from an array bound if it is
22156 not otherwise deduced." */
22158 static void
22160 {
22165 }
22167 /* Most parms like fn_type_unification.
22169 If SUBR is 1, we're being called recursively (to unify the
22170 arguments of a function or method parameter of a function
22171 template).
22173 CHECKS is a pointer to a vector of access checks encountered while
22174 substituting default template arguments. */
22176 static int
22178 tree full_targs,
22179 tree xparms,
22183 unification_kind_t strict,
22186 {
22191 tree parms;
22202 /* Reset the number of non-defaulted template arguments contained
22203 in TARGS. */
22206 again:
22214 {
22219 /* For a function parameter pack that occurs at the end of the
22220 parameter-declaration-list, the type A of each remaining
22221 argument of the call is compared with the type P of the
22222 declarator-id of the function parameter pack. */
22228 /* For a function parameter pack that does not occur at the
22229 end of the parameter-declaration-list, the type of the
22230 parameter pack is a non-deduced context. */
22237 explain_p))
22239 }
22244 {
22245 /* Unify the remaining arguments with the pack expansion type. */
22246 tree argvec;
22249 /* Allocate a TREE_VEC and copy in all of the arguments */
22254 /* Copy the parameter into parmvec. */
22260 /* Advance to the end of the list of parameters. */
22262 }
22264 /* Fail if we've reached the end of the parm list, and more args
22265 are present, and the parm list isn't variadic. */
22268 /* Fail if parms are left and they don't have default values and
22269 they aren't all deduced as empty packs (c++/57397). This is
22270 consistent with sufficient_parms_p. */
22273 {
22277 do
22278 {
22281 count++;
22283 }
22287 type_pack_p);
22288 }
22291 {
22292 tsubst_flags_t complain = (explain_p
22293 ? tf_warning_or_error
22298 {
22302 /* Clear the "incomplete" flags on all argument packs now so that
22303 substituting them into later default arguments works. */
22305 {
22308 }
22316 {
22321 }
22323 /* If this is an undeduced nontype parameter that depends on
22324 a type parameter, try another pass; its type may have been
22325 deduced from a later argument than the one from which
22326 this parameter can be deduced. */
22330 {
22333 }
22335 /* Core issue #226 (C++0x) [temp.deduct]:
22337 If a template argument has not been deduced, its
22338 default template argument, if any, is used.
22340 When we are in C++98 mode, TREE_PURPOSE will either
22341 be NULL_TREE or ERROR_MARK_NODE, so we do not need
22342 to explicitly check cxx_dialect here. */
22344 /* OK, there is a default argument. Wait until after the
22345 conversion check to do substitution. */
22348 /* If the type parameter is a parameter pack, then it will
22349 be deduced to an empty parameter pack. */
22351 {
22352 tree arg;
22355 {
22358 }
22359 else
22366 }
22369 }
22371 /* Now substitute into the default template arguments. */
22373 {
22389 {
22390 /* The type of this non-type parameter depends on undeduced
22391 parameters. Don't try to use its default argument yet,
22392 since we might deduce an argument for it on the next pass,
22393 but do check whether the arguments we already have cause
22394 substitution failure, so that that happens before we try
22395 later default arguments (78489). */
22398 NULL_TREE);
22402 else
22404 }
22405 else
22406 {
22407 /* Even if the call is happening in template context, getting
22408 here means it's non-dependent, and a default argument is
22409 considered a separate definition under [temp.decls], so we can
22410 do this substitution without processing_template_decl. This
22411 is important if the default argument contains something that
22412 might be instantiation-dependent like access (87480). */
22413 processing_template_decl_sentinel s;
22416 {
22417 /* First instatiate in template context, in case we still
22418 depend on undeduced template parameters. */
22421 NULL_TREE);
22425 /* We replaced all the tparms, substitute again out of
22426 template context. */
22428 }
22431 NULL_TREE);
22438 else
22440 }
22449 {
22451 /* The position of the first default template argument,
22452 is also the number of non-defaulted arguments in TARGS.
22453 Record that. */
22456 }
22457 }
22461 }
22467 }
22469 /* Subroutine of type_unification_real. Args are like the variables
22470 at the call site. ARG is an overloaded function (or template-id);
22471 we try deducing template args from each of the overloads, and if
22472 only one succeeds, we go with that. Modifies TARGS and returns
22473 true on success. */
22475 static bool
22477 tree targs,
22478 tree parm,
22479 tree arg,
22480 unification_kind_t strict,
22483 {
22490 {
22493 }
22494 else
22498 /* Handle `&x' where `x' is some static or non-static member
22499 function name. */
22505 /* Strip baselink information. */
22510 {
22511 /* If we got some explicit template args, we need to plug them into
22512 the affected templates before we try to unify, in case the
22513 explicit args will completely resolve the templates in question. */
22520 {
22533 {
22538 {
22539 /* Instantiate the function to deduce its return type. */
22543 }
22552 {
22555 }
22556 }
22559 }
22560 /* If no templates (or more than one) are fully resolved by the
22561 explicit arguments, this template-id is a non-deduced context; it
22562 could still be OK if we deduce all template arguments for the
22563 enclosing call through other arguments. */
22566 }
22568 /* If ARG is, for example, "(0, &f)" then its type will be unknown
22569 -- but the deduction does not succeed because the expression is
22570 not just the function on its own. */
22572 else
22574 {
22579 {
22582 }
22583 }
22585 /* [temp.deduct.type] A template-argument can be deduced from a pointer
22586 to function or pointer to member function argument if the set of
22587 overloaded functions does not contain function templates and at most
22588 one of a set of overloaded functions provides a unique match.
22590 So if we found multiple possibilities, we return success but don't
22591 deduce anything. */
22594 {
22598 {
22603 /* Don't forget explicit template arguments in a pack. */
22607 }
22608 }
22613 }
22615 /* Core DR 115: In contexts where deduction is done and fails, or in
22616 contexts where deduction is not done, if a template argument list is
22617 specified and it, along with any default template arguments, identifies
22618 a single function template specialization, then the template-id is an
22619 lvalue for the function template specialization. */
22621 tree
22623 {
22636 {
22639 }
22641 {
22644 }
22646 {
22649 }
22652 {
22656 /* If we got some explicit template args, we need to plug them into
22657 the affected templates before we try to unify, in case the
22658 explicit args will completely resolve the templates in question. */
22666 {
22679 {
22682 {
22685 }
22688 {
22691 }
22692 }
22693 }
22695 {
22703 {
22704 tree base
22707 }
22711 }
22713 /* There were no good options and at least one bad one, so let the
22714 user know what the problem is. */
22716 }
22718 }
22720 /* As above, but error out if the expression remains overloaded. */
22722 tree
22724 {
22727 {
22731 }
22733 }
22735 /* Subroutine of resolve_overloaded_unification; does deduction for a single
22736 overload. Fills TARGS with any deduced arguments, or error_mark_node if
22737 different overloads deduce different arguments for a given parm.
22738 ADDR_P is true if the expression for which deduction is being
22739 performed was of the form "& fn" rather than simply "fn".
22741 Returns 1 on success. */
22743 static int
22745 tree orig_targs,
22746 tree targs,
22747 tree parm,
22748 tree arg,
22749 unification_kind_t strict,
22753 {
22755 tree tempargs;
22761 /* [temp.deduct.type] A template-argument can be deduced from a pointer
22762 to function or pointer to member function argument if the set of
22763 overloaded functions does not contain function templates and at most
22764 one of a set of overloaded functions provides a unique match.
22766 So if this is a template, just return success. */
22779 /* We don't copy orig_targs for this because if we have already deduced
22780 some template args from previous args, unify would complain when we
22781 try to deduce a template parameter for the same argument, even though
22782 there isn't really a conflict. */
22789 /* First make sure we didn't deduce anything that conflicts with
22790 explicitly specified args. */
22792 {
22799 /* Since we're unifying against ourselves, we will fill in
22800 template args used in the function parm list with our own
22801 template parms. Discard them. */
22804 {
22805 /* Check that the argument at each index of the deduced argument pack
22806 is equivalent to the corresponding explicitly specified argument.
22807 We may have deduced more arguments than were explicitly specified,
22808 and that's OK. */
22810 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
22811 that's wrong if we deduce the same argument pack from multiple
22812 function arguments: it's only incomplete the first time. */
22825 }
22828 }
22831 {
22836 }
22839 }
22841 /* PARM is a template class (perhaps with unbound template
22842 parameters). ARG is a fully instantiated type. If ARG can be
22843 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
22844 TARGS are as for unify. */
22846 static tree
22849 {
22850 tree copy_of_targs;
22860 /* We need to make a new template argument vector for the call to
22861 unify. If we used TARGS, we'd clutter it up with the result of
22862 the attempted unification, even if this class didn't work out.
22863 We also don't want to commit ourselves to all the unifications
22864 we've already done, since unification is supposed to be done on
22865 an argument-by-argument basis. In other words, consider the
22866 following pathological case:
22868 template <int I, int J, int K>
22869 struct S {};
22871 template <int I, int J>
22872 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
22874 template <int I, int J, int K>
22875 void f(S<I, J, K>, S<I, I, I>);
22877 void g() {
22878 S<0, 0, 0> s0;
22879 S<0, 1, 2> s2;
22881 f(s0, s2);
22882 }
22884 Now, by the time we consider the unification involving `s2', we
22885 already know that we must have `f<0, 0, 0>'. But, even though
22886 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
22887 because there are two ways to unify base classes of S<0, 1, 2>
22888 with S<I, I, I>. If we kept the already deduced knowledge, we
22889 would reject the possibility I=1. */
22893 {
22897 }
22899 /* If unification failed, we're done. */
22905 }
22907 /* Given a template type PARM and a class type ARG, find the unique
22908 base type in ARG that is an instance of PARM. We do not examine
22909 ARG itself; only its base-classes. If there is not exactly one
22910 appropriate base class, return NULL_TREE. PARM may be the type of
22911 a partial specialization, as well as a plain template type. Used
22912 by unify. */
22914 static enum template_base_result
22917 {
22919 tree binfo;
22925 {
22926 /* The type could not be completed. */
22929 }
22931 /* Walk in inheritance graph order. The search order is not
22932 important, and this avoids multiple walks of virtual bases. */
22934 {
22939 {
22940 /* If there is more than one satisfactory baseclass, then:
22942 [temp.deduct.call]
22944 If they yield more than one possible deduced A, the type
22945 deduction fails.
22947 applies. */
22949 {
22950 /* [temp.deduct.call]/4.3: If there is a class C that is a
22951 (direct or indirect) base class of D and derived (directly or
22952 indirectly) from a class B and that would be a valid deduced
22953 A, the deduced A cannot be B or pointer to B, respectively. */
22955 /* Ignore r. */
22959 else
22960 {
22963 }
22964 }
22967 }
22968 }
22972 }
22974 /* Returns the level of DECL, which declares a template parameter. */
22976 static int
22978 {
22980 {
22990 }
22992 }
22994 /* Decide whether ARG can be unified with PARM, considering only the
22995 cv-qualifiers of each type, given STRICT as documented for unify.
22996 Returns nonzero iff the unification is OK on that basis. */
22998 static int
23000 {
23006 {
23007 /* Although a CVR qualifier is ignored when being applied to a
23008 substituted template parameter ([8.3.2]/1 for example), that
23009 does not allow us to unify "const T" with "int&" because both
23010 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
23011 It is ok when we're allowing additional CV qualifiers
23012 at the outer level [14.8.2.1]/3,1st bullet. */
23021 }
23032 }
23034 /* Determines the LEVEL and INDEX for the template parameter PARM. */
23035 void
23037 {
23041 {
23044 }
23045 else
23046 {
23049 }
23050 }
23052 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
23053 do { \
23054 if (unify (TP, TA, P, A, S, EP)) \
23055 return 1; \
23056 } while (0)
23058 /* Unifies the remaining arguments in PACKED_ARGS with the pack
23059 expansion at the end of PACKED_PARMS. Returns 0 if the type
23060 deduction succeeds, 1 otherwise. STRICT is the same as in
23061 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
23062 function call argument list. We'll need to adjust the arguments to make them
23063 types. SUBR tells us if this is from a recursive call to
23064 type_unification_real, or for comparing two template argument
23065 lists. */
23067 static int
23071 {
23072 tree parm
23078 /* Add in any args remembered from an earlier partial instantiation. */
23086 /* Determine the parameter packs we will be deducing from the
23087 pattern, and record their current deductions. */
23090 {
23094 /* Only template parameter packs can be deduced, not e.g. function
23095 parameter packs or __bases or __integer_pack. */
23099 /* Determine the index and level of this parameter pack. */
23104 /* Keep track of the parameter packs and their corresponding
23105 argument packs. */
23108 }
23110 /* Loop through all of the arguments that have not yet been
23111 unified and unify each with the pattern. */
23113 {
23114 tree parm;
23118 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
23119 or the element of its argument pack at the current index if
23120 this argument was explicitly specified. */
23122 {
23131 {
23134 }
23136 }
23138 /* If we had explicit template arguments, substitute them into the
23139 pattern before deduction. */
23141 {
23142 /* Some arguments might still be unspecified or dependent. */
23150 NULL_TREE);
23155 }
23156 else
23159 /* Unify the pattern with the current argument. */
23161 explain_p))
23164 /* For each parameter pack, collect the deduced value. */
23166 {
23172 }
23173 }
23175 /* Verify that the results of unification with the parameter packs
23176 produce results consistent with what we've seen before, and make
23177 the deduced argument packs available. */
23179 {
23186 /* By default keep the original deduced argument pack.
23187 If necessary, more specific code is going to update the
23188 resulting deduced argument later down in this function. */
23192 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
23193 actually deduce anything. */
23201 {
23202 /* If we had fewer function args than explicit template args,
23203 just use the explicits. */
23208 }
23211 {
23212 tree result;
23213 /* Build the deduced *_ARGUMENT_PACK. */
23215 {
23218 }
23219 else
23224 /* Note the deduced argument packs for this parameter
23225 pack. */
23227 }
23231 {
23232 /* We only had the explicitly-provided arguments before, but
23233 now we have a complete set of arguments. */
23239 }
23240 else
23241 {
23245 /* During template argument deduction for the aggregate deduction
23246 candidate, the number of elements in a trailing parameter pack
23247 is only deduced from the number of remaining function
23248 arguments if it is not otherwise deduced. */
23255 /* Inconsistent unification of this parameter pack. */
23257 bad_old_arg,
23258 bad_new_arg);
23259 }
23260 }
23263 }
23265 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
23266 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
23267 parameters and return value are as for unify. */
23269 static int
23273 {
23274 tree parm_max;
23275 tree arg_max;
23279 /* Our representation of array types uses "N - 1" as the
23280 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
23281 not an integer constant. We cannot unify arbitrarily
23282 complex expressions, so we eliminate the MINUS_EXPRs
23283 here. */
23287 {
23290 }
23294 {
23295 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
23296 trying to unify the type of a variable with the type
23297 of a template parameter. For example:
23299 template <unsigned int N>
23300 void f (char (&) [N]);
23301 int g();
23302 void h(int i) {
23303 char a[g(i)];
23304 f(a);
23305 }
23307 Here, the type of the ARG will be "int [g(i)]", and
23308 may be a SAVE_EXPR, etc. */
23312 }
23314 /* If only one of the bounds used a MINUS_EXPR, compensate
23315 by adding one to the other bound. */
23318 integer_type_node,
23319 parm_max,
23320 integer_one_node);
23323 integer_type_node,
23324 arg_max,
23325 integer_one_node);
23329 }
23331 /* Returns whether T, a P or A in unify, is a type, template or expression. */
23335 static pa_kind_t
23337 {
23346 else
23348 }
23350 /* Deduce the value of template parameters. TPARMS is the (innermost)
23351 set of template parameters to a template. TARGS is the bindings
23352 for those template parameters, as determined thus far; TARGS may
23353 include template arguments for outer levels of template parameters
23354 as well. PARM is a parameter to a template function, or a
23355 subcomponent of that parameter; ARG is the corresponding argument.
23356 This function attempts to match PARM with ARG in a manner
23357 consistent with the existing assignments in TARGS. If more values
23358 are deduced, then TARGS is updated.
23360 Returns 0 if the type deduction succeeds, 1 otherwise. The
23361 parameter STRICT is a bitwise or of the following flags:
23363 UNIFY_ALLOW_NONE:
23364 Require an exact match between PARM and ARG.
23365 UNIFY_ALLOW_MORE_CV_QUAL:
23366 Allow the deduced ARG to be more cv-qualified (by qualification
23367 conversion) than ARG.
23368 UNIFY_ALLOW_LESS_CV_QUAL:
23369 Allow the deduced ARG to be less cv-qualified than ARG.
23370 UNIFY_ALLOW_DERIVED:
23371 Allow the deduced ARG to be a template base class of ARG,
23372 or a pointer to a template base class of the type pointed to by
23373 ARG.
23374 UNIFY_ALLOW_INTEGER:
23375 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
23376 case for more information.
23377 UNIFY_ALLOW_OUTER_LEVEL:
23378 This is the outermost level of a deduction. Used to determine validity
23379 of qualification conversions. A valid qualification conversion must
23380 have const qualified pointers leading up to the inner type which
23381 requires additional CV quals, except at the outer level, where const
23382 is not required [conv.qual]. It would be normal to set this flag in
23383 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
23384 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
23385 This is the outermost level of a deduction, and PARM can be more CV
23386 qualified at this point.
23387 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
23388 This is the outermost level of a deduction, and PARM can be less CV
23389 qualified at this point. */
23391 static int
23394 {
23396 tree targ;
23397 tree tparm;
23399 tsubst_flags_t complain = (explain_p
23400 ? tf_warning_or_error
23403 /* I don't think this will do the right thing with respect to types.
23404 But the only case I've seen it in so far has been array bounds, where
23405 signedness is the only information lost, and I think that will be
23406 okay. VIEW_CONVERT_EXPR can appear with class NTTP, thanks to
23407 finish_id_expression_1, and are also OK. */
23415 /* We can't deduce anything from this, but we might get all the
23416 template args from other function args. */
23422 /* If PARM uses template parameters, then we can't bail out here,
23423 even if ARG == PARM, since we won't record unifications for the
23424 template parameters. We might need them if we're trying to
23425 figure out which of two things is more specialized. */
23429 /* Handle init lists early, so the rest of the function can assume
23430 we're dealing with a type. */
23432 {
23439 /* We can only deduce from an initializer list argument if the
23440 parameter is std::initializer_list or an array; otherwise this
23441 is a non-deduced context. */
23446 else
23447 {
23449 /* Deduction is defined in terms of a single type, so just punt
23450 on the (bizarre) std::initializer_list<T...>. */
23453 }
23458 /* If ELTTYPE has no deducible template parms, skip deduction from
23460 else
23462 {
23469 {
23473 /* It should only be possible to get here for a call. */
23475 elt_strict |= maybe_adjust_types_for_deduction
23478 }
23481 explain_p);
23482 }
23486 {
23487 /* Also deduce from the length of the initializer list. */
23494 }
23496 /* If the std::initializer_list<T> deduction worked, replace the
23497 deduced A with std::initializer_list<A>. */
23499 {
23504 }
23506 }
23508 /* If parm and arg aren't the same kind of thing (template, type, or
23509 expression), fail early. */
23513 /* Immediately reject some pairs that won't unify because of
23514 cv-qualification mismatches. */
23517 /* It is the elements of the array which hold the cv quals of an array
23518 type, and the elements might be template type parms. We'll check
23519 when we recurse. */
23521 /* We check the cv-qualifiers when unifying with template type
23522 parameters below. We want to allow ARG `const T' to unify with
23523 PARM `T' for example, when computing which of two templates
23524 is more specialized, for example. */
23538 {
23542 /* In a type which contains a nested-name-specifier, template
23543 argument values cannot be deduced for template parameters used
23544 within the nested-name-specifier. */
23556 /* The PARM is not one we're trying to unify. Just check
23557 to see if it matches ARG. */
23558 {
23563 else
23565 }
23572 /* Check for mixed types and values. */
23580 {
23583 {
23584 /* First try to match ARG directly. */
23586 explain_p);
23588 {
23589 /* Otherwise, look for a suitable base of ARG, as below. */
23596 }
23597 }
23598 /* ARG must be constructed from a template class or a template
23599 template parameter. */
23604 /* Deduce arguments T, i from TT<T> or TT<i>. */
23610 /* If the template is a template template parameter, use the
23611 TEMPLATE_TEMPLATE_PARM for matching. */
23614 /* Fall through to deduce template name. */
23615 }
23619 {
23620 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
23622 /* Simple cases: Value already set, does match or doesn't. */
23627 }
23628 else
23629 {
23630 /* If PARM is `const T' and ARG is only `int', we don't have
23631 a match unless we are allowing additional qualification.
23632 If ARG is `const int' and PARM is just `T' that's OK;
23633 that binds `const int' to `T'. */
23638 /* Consider the case where ARG is `const volatile int' and
23639 PARM is `const T'. Then, T should be `volatile int'. */
23640 arg = cp_build_qualified_type_real
23645 /* Simple cases: Value already set, does match or doesn't. */
23651 /* Make sure that ARG is not a variable-sized array. (Note
23652 that were talking about variable-sized arrays (like
23653 `int[n]'), rather than arrays of unknown size (like
23654 `int[]').) We'll get very confused by such a type since
23655 the bound of the array is not constant, and therefore
23656 not mangleable. Besides, such types are not allowed in
23657 ISO C++, so we can do as we please here. We do allow
23658 them for 'auto' deduction, since that isn't ABI-exposed. */
23662 /* Strip typedefs as in convert_template_argument. */
23664 }
23666 /* If ARG is a parameter pack or an expansion, we cannot unify
23667 against it unless PARM is also a parameter pack. */
23672 /* If the argument deduction results is a METHOD_TYPE,
23673 then there is a problem.
23674 METHOD_TYPE doesn't map to any real C++ type the result of
23675 the deduction cannot be of that type. */
23689 {
23690 /* The PARM is not one we're trying to unify. Just check
23691 to see if it matches ARG. */
23697 }
23703 {
23707 /* We're deducing from an array bound, the type doesn't matter. */
23713 }
23715 /* [temp.deduct.type] If, in the declaration of a function template
23716 with a non-type template-parameter, the non-type
23717 template-parameter is used in an expression in the function
23718 parameter-list and, if the corresponding template-argument is
23719 deduced, the template-argument type shall match the type of the
23720 template-parameter exactly, except that a template-argument
23721 deduced from an array bound may be of any integral type.
23722 The non-type parameter might use already deduced type parameters. */
23725 /* We don't have enough levels of args to do any substitution. This
23727 else
23728 {
23734 {
23739 }
23740 }
23743 /* Template-parameter dependent expression. Just accept it for now.
23744 It will later be processed in convert_template_argument. */
23745 ;
23749 /* OK. Ignore top-level quals here because a class-type template
23753 /* Convert the ARG to the type of PARM; the deduced non-type
23754 template argument must exactly match the types of the
23755 corresponding parameter. */
23758 {
23759 /* We haven't deduced the type of this parameter yet. */
23761 /* We deduce from array bounds in try_array_deduction. */
23764 {
23765 /* Deduce it from the non-type argument. */
23770 /* Now check whether the type of this parameter is still
23771 dependent, and give up if so. */
23777 }
23778 else
23779 /* Try again later. */
23781 }
23782 else
23785 /* If ARG is a parameter pack or an expansion, we cannot unify
23786 against it unless PARM is also a parameter pack. */
23791 {
23794 }
23799 {
23800 /* A pointer-to-member constant can be unified only with
23801 another constant. */
23805 /* Just unify the class member. It would be useless (and possibly
23806 wrong, depending on the strict flags) to unify also
23807 PTRMEM_CST_CLASS, because we want to be sure that both parm and
23808 arg refer to the same variable, even if through different
23809 classes. For instance:
23811 struct A { int x; };
23812 struct B : A { };
23814 Unification of &A::x and &B::x must succeed. */
23817 }
23820 {
23824 /* [temp.deduct.call]
23826 A can be another pointer or pointer to member type that can
23827 be converted to the deduced A via a qualification
23828 conversion (_conv.qual_).
23830 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
23831 This will allow for additional cv-qualification of the
23832 pointed-to types if appropriate. */
23835 /* The derived-to-base conversion only persists through one
23836 level of pointers. */
23841 }
23874 /* We have already checked cv-qualification at the top of the
23875 function. */
23879 /* As far as unification is concerned, this wins. Later checks
23880 will invalidate it if necessary. */
23883 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
23884 /* Type INTEGER_CST can come from ordinary constant template args. */
23896 {
23906 /* Check for pack expansions in the parameters. */
23908 {
23910 {
23912 /* We can unify against something with a trailing
23913 parameter pack. */
23915 else
23916 /* [temp.deduct.type]/9: If the template argument list of
23917 P contains a pack expansion that is not the last
23918 template argument, the entire template argument list
23919 is a non-deduced context. */
23921 }
23922 }
23924 /* If we don't have enough arguments to satisfy the parameters
23925 (not counting the pack expression at the end), or we have
23926 too many arguments for a parameter list that doesn't end in
23927 a pack expression, we can't unify. */
23933 /* Unify all of the parameters that precede the (optional)
23934 pack expression. */
23936 {
23941 }
23944 DEDUCE_EXACT,
23947 }
23955 {
23963 }
23968 {
23972 {
23973 /* First, we try to unify the PARM and ARG directly. */
23978 {
23979 /* Fallback to the special case allowed in
23980 [temp.deduct.call]:
23982 If P is a class, and P has the form
23983 template-id, then A can be a derived class of
23984 the deduced A. Likewise, if P is a pointer to
23985 a class of the form template-id, A can be a
23986 pointer to a derived class pointed to by the
23987 deduced A. */
23993 {
23994 /* Don't give the derived diagnostic if we're
23995 already dealing with the same template. */
23996 bool same_template
24002 }
24003 }
24004 }
24008 /* Perhaps PARM is something like S<U> and ARG is S<int>.
24009 Then, we should unify `int' and `U'. */
24011 else
24012 /* There's no chance of unification succeeding. */
24017 }
24024 {
24027 tree a;
24033 /* CV qualifications for methods can never be deduced, they must
24034 match exactly. We need to check them explicitly here,
24035 because type_unification_real treats them as any other
24036 cv-qualified parameter. */
24038 && (!check_cv_quals_for_unify
24066 {
24078 }
24081 }
24084 /* Unify a pointer to member with a pointer to member function, which
24085 deduces the type of the member as a function type. */
24087 {
24088 /* Check top-level cv qualifiers */
24096 /* Determine the type of the function we are unifying against. */
24100 }
24119 /* Matched cases are handled by the ARG == PARM test above. */
24123 /* We might get a variable as a non-type template argument in parm if the
24124 corresponding parameter is type-dependent. Make any necessary
24125 adjustments based on whether arg is a reference. */
24129 {
24134 }
24135 /* Now use the normal expression code to check whether they match. */
24146 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
24147 or UNDERLYING_TYPE nodes. */
24151 /* Unification fails if we hit an error node. */
24156 {
24166 }
24167 /* FALLTHRU */
24170 /* An unresolved overload is a nondeduced context. */
24176 expr:
24177 /* We must be looking at an expression. This can happen with
24178 something like:
24180 template <int I>
24181 void foo(S<I>, S<I + 2>);
24183 or
24185 template<typename T>
24186 void foo(A<T, T{}>);
24188 This is a "non-deduced context":
24190 [deduct.type]
24192 The non-deduced contexts are:
24194 --A non-type template argument or an array bound in which
24195 a subexpression references a template parameter.
24197 In these cases, we assume deduction succeeded, but don't
24198 actually infer any unifications. */
24203 else
24205 }
24206 }
24207 #undef RECUR_AND_CHECK_FAILURE
24208 \f
24209 /* Note that DECL can be defined in this translation unit, if
24210 required. */
24212 static void
24214 {
24215 tree clone;
24219 }
24221 /* Called if RESULT is explicitly instantiated, or is a member of an
24222 explicitly instantiated class. */
24224 void
24226 {
24229 /* If this entity has already been written out, it's too late to
24230 make any modifications. */
24234 /* consteval functions are never emitted. */
24239 /* For anonymous namespace we don't need to do anything. */
24241 {
24244 }
24247 /* The TREE_PUBLIC flag for function declarations will have been
24248 set correctly by tsubst. */
24251 /* This might have been set by an earlier implicit instantiation. */
24255 {
24258 }
24259 else
24260 {
24263 /* Always make artificials weak. */
24266 /* For WIN32 we also want to put explicit instantiations in
24267 linkonce sections. */
24272 /* If the function has already been instantiated, clear DECL_EXTERNAL,
24273 since start_preparsed_function wouldn't have if we had an earlier
24274 extern explicit instantiation. */
24276 }
24278 /* If EXTERN_P, then this function will not be emitted -- unless
24279 followed by an explicit instantiation, at which point its linkage
24280 will be adjusted. If !EXTERN_P, then this function will be
24281 emitted here. In neither circumstance do we want
24282 import_export_decl to adjust the linkage. */
24284 }
24286 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
24287 important template arguments. If any are missing, we check whether
24288 they're important by using error_mark_node for substituting into any
24289 args that were used for partial ordering (the ones between ARGS and END)
24290 and seeing if it bubbles up. */
24292 static bool
24294 {
24299 {
24302 }
24304 {
24308 }
24310 }
24312 /* Given two function templates PAT1 and PAT2, return:
24314 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
24315 -1 if PAT2 is more specialized than PAT1.
24316 0 if neither is more specialized.
24318 LEN indicates the number of parameters we should consider
24319 (defaulted parameters should not be considered).
24321 The 1998 std underspecified function template partial ordering, and
24322 DR214 addresses the issue. We take pairs of arguments, one from
24323 each of the templates, and deduce them against each other. One of
24324 the templates will be more specialized if all the *other*
24325 template's arguments deduce against its arguments and at least one
24326 of its arguments *does* *not* deduce against the other template's
24327 corresponding argument. Deduction is done as for class templates.
24328 The arguments used in deduction have reference and top level cv
24329 qualifiers removed. Iff both arguments were originally reference
24330 types *and* deduction succeeds in both directions, an lvalue reference
24331 wins against an rvalue reference and otherwise the template
24332 with the more cv-qualified argument wins for that pairing (if
24333 neither is more cv-qualified, they both are equal). Unlike regular
24334 deduction, after all the arguments have been deduced in this way,
24335 we do *not* verify the deduced template argument values can be
24336 substituted into non-deduced contexts.
24338 The logic can be a bit confusing here, because we look at deduce1 and
24339 targs1 to see if pat2 is at least as specialized, and vice versa; if we
24340 can find template arguments for pat1 to make arg1 look like arg2, that
24341 means that arg2 is at least as specialized as arg1. */
24343 int
24345 {
24358 /* Remove the this parameter from non-static member functions. If
24359 one is a non-static member function and the other is not a static
24360 member function, remove the first parameter from that function
24361 also. This situation occurs for operator functions where we
24362 locate both a member function (with this pointer) and non-member
24363 operator (with explicit first operand). */
24365 {
24370 }
24372 {
24375 {
24376 len--;
24378 }
24379 }
24381 /* If only one is a conversion operator, they are unordered. */
24385 /* Consider the return type for a conversion function */
24387 {
24390 len++;
24391 }
24393 processing_template_decl++;
24399 /* Stop when an ellipsis is seen. */
24401 {
24412 {
24413 /* When both arguments are pack expansions, we need only
24414 unify the patterns themselves. */
24418 /* This is the last comparison we need to do. */
24420 }
24423 {
24427 }
24430 {
24434 }
24440 {
24446 /* Setup the parameter vector, which contains only ARG1. */
24449 /* Setup the argument vector, which contains the remaining
24450 arguments. */
24459 /* We cannot deduce in the other direction, because ARG1 is
24460 a pack expansion but ARG2 is not. */
24462 }
24464 {
24470 /* Setup the parameter vector, which contains only ARG1. */
24473 /* Setup the argument vector, which contains the remaining
24474 arguments. */
24483 /* We cannot deduce in the other direction, because ARG2 is
24484 a pack expansion but ARG1 is not.*/
24486 }
24488 else
24489 {
24490 /* The normal case, where neither argument is a pack
24491 expansion. */
24498 }
24500 /* If we couldn't deduce arguments for tparms1 to make arg1 match
24501 arg2, then arg2 is not as specialized as arg1. */
24507 /* "If, for a given type, deduction succeeds in both directions
24508 (i.e., the types are identical after the transformations above)
24509 and both P and A were reference types (before being replaced with
24510 the type referred to above):
24511 - if the type from the argument template was an lvalue reference and
24512 the type from the parameter template was not, the argument type is
24513 considered to be more specialized than the other; otherwise,
24514 - if the type from the argument template is more cv-qualified
24515 than the type from the parameter template (as described above),
24516 the argument type is considered to be more specialized than the other;
24517 otherwise,
24518 - neither type is more specialized than the other." */
24521 {
24523 {
24526 else
24528 }
24530 {
24535 }
24536 }
24539 /* We've failed to deduce something in either direction.
24540 These must be unordered. */
24545 /* We have already processed all of the arguments in our
24546 handing of the pack expansion type. */
24551 }
24553 /* "In most cases, all template parameters must have values in order for
24554 deduction to succeed, but for partial ordering purposes a template
24555 parameter may remain without a value provided it is not used in the
24556 types being used for partial ordering."
24558 Thus, if we are missing any of the targs1 we need to substitute into
24559 origs1, then pat2 is not as specialized as pat1. This can happen when
24560 there is a nondeduced context. */
24566 processing_template_decl--;
24568 /* If both deductions succeed, the partial ordering selects the more
24569 constrained template. */
24570 /* P2113: If the corresponding template-parameters of the
24571 template-parameter-lists are not equivalent ([temp.over.link]) or if
24572 the function parameters that positionally correspond between the two
24573 templates are not of the same type, neither template is more
24574 specialized than the other. */
24579 {
24585 }
24587 /* All things being equal, if the next argument is a pack expansion
24588 for one function but not for the other, prefer the
24589 non-variadic function. FIXME this is bogus; see c++/41958. */
24593 {
24596 }
24602 else
24604 }
24606 /* Determine which of two partial specializations of TMPL is more
24607 specialized.
24609 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
24610 to the first partial specialization. The TREE_PURPOSE is the
24611 innermost set of template parameters for the partial
24612 specialization. PAT2 is similar, but for the second template.
24614 Return 1 if the first partial specialization is more specialized;
24615 -1 if the second is more specialized; 0 if neither is more
24616 specialized.
24618 See [temp.class.order] for information about determining which of
24619 two templates is more specialized. */
24621 static int
24623 {
24624 tree targs;
24633 /* Just like what happens for functions, if we are ordering between
24634 different template specializations, we may encounter dependent
24635 types in the arguments, and we need our dependency check functions
24636 to behave correctly. */
24640 {
24643 }
24647 {
24650 }
24653 /* If both deductions succeed, the partial ordering selects the more
24654 constrained template. */
24658 /* In the case of a tie where at least one of the templates
24659 has a parameter pack at the end, the template with the most
24660 non-packed parameters wins. */
24662 && any_deductions
24665 {
24671 /* We don't count the pack expansion at the end. */
24681 }
24684 }
24686 /* Return the template arguments that will produce the function signature
24687 DECL from the function template FN, with the explicit template
24688 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
24689 also match. Return NULL_TREE if no satisfactory arguments could be
24690 found. */
24692 static tree
24694 {
24698 tree decl_arg_types;
24701 tree arg;
24705 /* Never do unification on the 'this' parameter. */
24727 }
24729 /* Return the innermost template arguments that, when applied to a partial
24730 specialization SPEC_TMPL of TMPL, yield the ARGS.
24732 For example, suppose we have:
24734 template <class T, class U> struct S {};
24735 template <class T> struct S<T*, int> {};
24737 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
24738 partial specialization and the ARGS will be {double*, int}. The resulting
24739 vector will be {double}, indicating that `T' is bound to `double'. */
24741 static tree
24743 {
24745 tree spec_args
24748 tree deduced_args;
24749 tree innermost_deduced_args;
24753 {
24757 innermost_deduced_args);
24758 }
24759 else
24763 again:
24772 {
24774 {
24780 }
24782 }
24785 {
24788 }
24790 /* Verify that nondeduced template arguments agree with the type
24791 obtained from argument deduction.
24793 For example:
24795 struct A { typedef int X; };
24796 template <class T, class U> struct C {};
24797 template <class T> struct C<T, typename T::X> {};
24799 Then with the instantiation `C<A, int>', we can deduce that
24800 `T' is `A' but unify () does not check whether `typename T::X'
24801 is `int'. */
24812 /* We only need to check the innermost arguments; the other
24813 arguments will always agree. */
24818 /* Now that we have bindings for all of the template arguments,
24819 ensure that the arguments deduced for the template template
24820 parameters have compatible template parameter lists. See the use
24821 of template_template_parm_bindings_ok_p in fn_type_unification
24822 for more information. */
24827 }
24829 // Compare two function templates T1 and T2 by deducing bindings
24830 // from one against the other. If both deductions succeed, compare
24831 // constraints to see which is more constrained.
24832 static int
24834 {
24839 {
24842 }
24845 {
24848 }
24850 // If both deductions succeed, then one may be more constrained.
24855 }
24857 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
24858 Return the TREE_LIST node with the most specialized template, if
24859 any. If there is no most specialized template, the error_mark_node
24860 is returned.
24862 Note that this function does not look at, or modify, the
24863 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
24864 returned is one of the elements of INSTANTIATIONS, callers may
24865 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
24866 and retrieve it from the value returned. */
24868 tree
24870 {
24877 {
24883 {
24884 /* Equally specialized, move to next function. If there
24885 is no next function, nothing's most specialized. */
24890 }
24891 }
24894 /* Now verify that champ is better than everything earlier in the
24895 instantiation list. */
24898 {
24901 }
24902 }
24904 processing_template_decl--;
24910 }
24912 /* If DECL is a specialization of some template, return the most
24913 general such template. Otherwise, returns NULL_TREE.
24915 For example, given:
24917 template <class T> struct S { template <class U> void f(U); };
24919 if TMPL is `template <class U> void S<int>::f(U)' this will return
24920 the full template. This function will not trace past partial
24921 specializations, however. For example, given in addition:
24923 template <class T> struct S<T*> { template <class U> void f(U); };
24925 if TMPL is `template <class U> void S<int*>::f(U)' this will return
24926 `template <class T> template <class U> S<T*>::f(U)'. */
24928 tree
24930 {
24932 {
24935 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
24936 template friend, or a FIELD_DECL for a capture pack. */
24939 }
24941 /* Look for more and more general templates. */
24943 {
24944 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
24945 (See cp-tree.h for details.) */
24954 /* Stop if we run into an explicitly specialized class template. */
24961 }
24964 }
24966 /* Return the most specialized of the template partial specializations
24967 which can produce TARGET, a specialization of some class or variable
24968 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
24969 a TEMPLATE_DECL node corresponding to the partial specialization, while
24970 the TREE_PURPOSE is the set of template arguments that must be
24971 substituted into the template pattern in order to generate TARGET.
24973 If the choice of partial specialization is ambiguous, a diagnostic
24974 is issued, and the error_mark_node is returned. If there are no
24975 partial specializations matching TARGET, then NULL_TREE is
24976 returned, indicating that the primary template should be used. */
24978 tree
24980 {
24982 tree t;
24983 tree champ;
24989 tree decl;
24991 {
24996 }
24998 {
25002 }
25004 {
25009 }
25010 else
25018 /* For determining which partial specialization to use, only the
25019 innermost args are interesting. */
25021 {
25024 }
25026 /* The caller hasn't called push_to_top_level yet, but we need
25027 get_partial_spec_bindings to be done in non-template context so that we'll
25028 fully resolve everything. */
25029 processing_template_decl_sentinel ptds;
25032 {
25035 tree spec_tmpl;
25037 {
25038 /* Substitute in the template args from the enclosing class. */
25044 }
25045 else
25050 {
25054 /* Keep the candidate only if the constraints are satisfied,
25055 or if we're not compiling with concepts. */
25058 {
25061 }
25062 }
25063 }
25073 {
25076 ;
25077 else
25078 {
25080 {
25083 {
25086 }
25087 }
25089 }
25090 }
25094 {
25097 {
25100 }
25101 }
25104 {
25111 else
25115 {
25120 }
25123 }
25126 }
25128 /* Explicitly instantiate DECL. */
25130 void
25132 {
25137 /* An error occurred, for which grokdeclarator has already issued
25138 an appropriate message. */
25141 {
25144 }
25146 {
25149 else
25152 }
25158 {
25159 /* There is an asymmetry here in the way VAR_DECLs and
25160 FUNCTION_DECLs are handled by grokdeclarator. In the case of
25161 the latter, the DECL we get back will be marked as a
25162 template instantiation, and the appropriate
25163 DECL_TEMPLATE_INFO will be set up. This does not happen for
25164 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
25165 should handle VAR_DECLs as it currently handles
25166 FUNCTION_DECLs. */
25168 {
25171 }
25174 {
25177 }
25179 {
25184 }
25185 }
25187 {
25190 }
25191 else
25194 /* Check for various error cases. Note that if the explicit
25195 instantiation is valid the RESULT will currently be marked as an
25196 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
25197 until we get here. */
25200 {
25201 /* DR 259 [temp.spec].
25203 Both an explicit instantiation and a declaration of an explicit
25204 specialization shall not appear in a program unless the explicit
25205 instantiation follows a declaration of the explicit specialization.
25207 For a given set of template parameters, if an explicit
25208 instantiation of a template appears after a declaration of an
25209 explicit specialization for that template, the explicit
25210 instantiation has no effect. */
25212 }
25214 {
25215 /* [temp.spec]
25217 No program shall explicitly instantiate any template more
25218 than once.
25220 We check DECL_NOT_REALLY_EXTERN so as not to complain when
25221 the first instantiation was `extern' and the second is not,
25222 and EXTERN_P for the opposite case. */
25225 /* If an "extern" explicit instantiation follows an ordinary
25226 explicit instantiation, the template is instantiated. */
25229 }
25231 {
25234 }
25236 {
25239 }
25242 ;
25244 {
25247 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
25250 }
25251 else
25259 }
25261 static void
25263 {
25269 {
25272 }
25273 }
25275 /* Perform an explicit instantiation of template class T. STORAGE, if
25276 non-null, is the RID for extern, inline or static. COMPLAIN is
25277 nonzero if this is called from the parser, zero if called recursively,
25278 since the standard is unclear (as detailed below). */
25280 void
25282 {
25284 {
25288 else
25291 }
25296 {
25299 t);
25301 }
25303 /* At most one of these will be true. */
25309 {
25311 {
25314 "ISO C++ 1998 forbids the use of %<extern%> on "
25316 }
25317 else
25319 "ISO C++ forbids the use of %qE"
25328 else
25330 storage);
25331 }
25334 /* DR 259 [temp.spec].
25336 Both an explicit instantiation and a declaration of an explicit
25337 specialization shall not appear in a program unless the
25338 explicit instantiation follows a declaration of the explicit
25339 specialization.
25341 For a given set of template parameters, if an explicit
25342 instantiation of a template appears after a declaration of an
25343 explicit specialization for that template, the explicit
25344 instantiation has no effect. */
25348 {
25349 /* We've already instantiated the template. */
25351 /* [temp.spec]
25353 No program shall explicitly instantiate any template more
25354 than once.
25356 If EXTERN_P then this is ok. */
25362 }
25370 /* In contrast to implicit instantiation, where only the
25371 declarations, and not the definitions, of members are
25372 instantiated, we have here:
25374 [temp.explicit]
25376 An explicit instantiation that names a class template
25377 specialization is also an explicit instantiation of the same
25378 kind (declaration or definition) of each of its members (not
25379 including members inherited from base classes and members
25380 that are templates) that has not been previously explicitly
25381 specialized in the translation unit containing the explicit
25382 instantiation, provided that the associated constraints, if
25383 any, of that member are satisfied by the template arguments
25384 of the explicit instantiation. */
25388 && !static_p
25392 {
25397 }
25399 {
25405 }
25406 }
25408 /* Given a function DECL, which is a specialization of TMPL, modify
25409 DECL to be a re-instantiation of TMPL with the same template
25410 arguments. TMPL should be the template into which tsubst'ing
25411 should occur for DECL, not the most general template.
25413 One reason for doing this is a scenario like this:
25415 template <class T>
25416 void f(const T&, int i);
25418 void g() { f(3, 7); }
25420 template <class T>
25421 void f(const T& t, const int i) { }
25423 Note that when the template is first instantiated, with
25424 instantiate_template, the resulting DECL will have no name for the
25425 first parameter, and the wrong type for the second. So, when we go
25426 to instantiate the DECL, we regenerate it. */
25428 static void
25430 {
25431 /* The arguments used to instantiate DECL, from the most general
25432 template. */
25433 tree code_pattern;
25437 /* Make sure that we can see identifiers, and compute access
25438 correctly. */
25442 {
25443 tree specs;
25447 /* Use the source location of the definition. */
25455 /* Instantiate a dynamic exception-specification. noexcept will be
25456 handled below. */
25459 {
25465 specs);
25466 }
25468 /* Merge parameter declarations. */
25472 {
25479 }
25481 /* Merge additional specifiers from the CODE_PATTERN. */
25487 }
25489 {
25498 }
25499 else
25503 }
25505 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
25506 substituted to get DECL. */
25508 tree
25510 {
25513 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
25514 for the instantiation. This is not always the most general
25515 template. Consider, for example:
25517 template <class T>
25518 struct S { template <class U> void f();
25519 template <> void f<int>(); };
25521 and an instantiation of S<double>::f<int>. We want TD to be the
25522 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
25524 more general template. */
25526 /* We must also deal with friend templates. Given:
25528 template <class T> struct S {
25529 template <class U> friend void f() {};
25530 };
25532 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
25533 so far as the language is concerned, but that's still
25534 where we get the pattern for the instantiation from. On
25535 other hand, if the definition comes outside the class, say:
25537 template <class T> struct S {
25538 template <class U> friend void f();
25539 };
25540 template <class U> friend void f() {}
25542 we don't need to look any further. That's what the check for
25543 DECL_INITIAL is for. */
25547 {
25548 /* The present template, TD, should not be a definition. If it
25549 were a definition, we should be using it! Note that we
25550 cannot restructure the loop to just keep going until we find
25551 a template with a definition, since that might go too far if
25552 a specialization was declared, but not defined. */
25554 /* Fetch the more general template. */
25556 }
25559 }
25561 /* Returns true if we need to instantiate this template instance even if we
25562 know we aren't going to emit it. */
25564 bool
25566 {
25567 /* We always instantiate inline functions so that we can inline them. An
25568 explicit instantiation declaration prohibits implicit instantiation of
25569 non-inline functions. With high levels of optimization, we would
25570 normally inline non-inline functions -- but we're not allowed to do
25571 that for "extern template" functions. Therefore, we check
25572 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
25576 /* And we need to instantiate static data members so that
25577 their initializers are available in integral constant
25578 expressions. */
25581 }
25583 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
25584 instantiate it now, modifying TREE_TYPE (fn). Returns false on
25585 error, true otherwise. */
25587 bool
25589 {
25593 /* Don't instantiate a noexcept-specification from template context. */
25599 {
25601 /* We're in start_preparsed_function, keep going. */
25608 }
25622 /* For a member friend template we can get a TEMPLATE_DECL. Let's use
25623 its FUNCTION_DECL for the rest of this function -- push_access_scope
25624 doesn't accept TEMPLATE_DECLs. */
25626 {
25629 }
25632 {
25637 }
25639 {
25643 {
25646 /* This might have failed because of an unparsed DMI, so
25647 let's try again later. */
25649 }
25651 {
25652 /* If hash_set::add returns true, the element was already there. */
25657 fn);
25659 }
25661 {
25668 {
25669 /* If needed, set current_class_ptr for the benefit of
25670 tsubst_copy/PARM_DECL. The exception pattern will
25671 refer to the parm of the template, not the
25672 instantiation. */
25675 {
25680 }
25681 }
25683 /* If this function is represented by a TEMPLATE_DECL, then
25684 the deferred noexcept-specification might still contain
25685 dependent types, even after substitution. And we need the
25686 dependency check functions to work in build_noexcept_spec. */
25690 /* Do deferred instantiation of the noexcept-specifier. */
25697 /* Build up the noexcept-specification. */
25707 }
25708 else
25713 }
25716 {
25717 /* This failed with a hard error, so let's go with false. */
25720 }
25727 }
25729 /* We're starting to process the function INST, an instantiation of PATTERN;
25730 add their parameters to local_specializations. */
25732 static void
25734 {
25738 {
25742 }
25744 {
25746 {
25749 }
25750 else
25751 {
25752 /* Register the (value) argument pack as a specialization of
25753 TMPL_PARM, then move on. */
25756 }
25757 }
25759 }
25761 /* Instantiate the body of D using PATTERN with ARGS. We have
25762 already determined PATTERN is the correct template to use.
25763 NESTED_P is true if this is a nested function, in which case
25764 PATTERN will be a FUNCTION_DECL not a TEMPLATE_DECL. */
25766 static void
25768 {
25773 {
25776 }
25777 else
25778 /* Only OMP reductions are nested. */
25785 bool push_to_top
25786 = !(current_function_decl
25792 else
25793 {
25798 }
25801 {
25802 /* The variable might be a lambda's extra scope, and that
25803 lambda's visibility depends on D's. */
25806 }
25808 /* Mark D as instantiated so that recursive calls to
25809 instantiate_decl do not try to instantiate it again. */
25813 /* Regenerate the declaration in case the template has been modified
25814 by a subsequent redeclaration. */
25817 /* We already set the file and line above. Reset them now in case
25818 they changed as a result of calling regenerate_decl_from_template. */
25822 {
25823 /* Clear out DECL_RTL; whatever was there before may not be right
25824 since we've reset the type of the declaration. */
25828 /* The initializer is placed in DECL_INITIAL by
25829 regenerate_decl_from_template so we don't need to
25830 push/pop_access_scope again here. Pull it out so that
25831 cp_finish_decl can process it. */
25837 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
25838 initializer. That function will defer actual emission until
25839 we have a chance to determine linkage. */
25842 /* Enter the scope of D so that access-checking works correctly. */
25852 }
25856 {
25857 /* Set up the list of local specializations. */
25861 /* Set up context. */
25864 else
25865 {
25869 }
25871 /* Create substitution entries for the parameters. */
25874 /* Substitute into the body of the function. */
25878 else
25879 {
25884 /* Set the current input_location to the end of the function
25885 so that finish_function knows where we are. */
25886 input_location
25889 /* Remember if we saw an infinite loop in the template. */
25890 current_function_infinite_loop
25892 }
25894 /* Finish the function. */
25897 else
25898 {
25901 }
25905 }
25907 /* We're not deferring instantiation any more. */
25913 else
25918 }
25920 /* Produce the definition of D, a _DECL generated from a template. If
25921 DEFER_OK is true, then we don't have to actually do the
25922 instantiation now; we just have to do it sometime. Normally it is
25923 an error if this is an explicit instantiation but D is undefined.
25924 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
25925 instantiated class template. */
25927 tree
25929 {
25931 tree gen_args;
25932 tree args;
25933 tree td;
25934 tree code_pattern;
25935 tree spec;
25936 tree gen_tmpl;
25944 /* This function should only be used to instantiate templates for
25945 functions and static member variables. */
25948 /* A concept is never instantiated. */
25954 /* We may have a pending instantiation of D itself. */
25957 /* Variables are never deferred; if instantiation is required, they
25958 are instantiated right away. That allows for better code in the
25959 case that an expression refers to the value of the variable --
25960 if the variable has a constant value the referring expression can
25961 take advantage of that fact. */
25965 /* Don't instantiate cloned functions. Instead, instantiate the
25966 functions they cloned. */
25975 /* D has already been instantiated or explicitly specialized, so
25976 there's nothing for us to do here.
25978 It might seem reasonable to check whether or not D is an explicit
25979 instantiation, and, if so, stop here. But when an explicit
25980 instantiation is deferred until the end of the compilation,
25981 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
25982 the instantiation. */
25985 /* Check to see whether we know that this template will be
25986 instantiated in some other file, as with "extern template"
25987 extension. */
25990 /* In general, we do not instantiate such templates. */
25997 /* We should already have the extra args. */
26001 /* And what's in the hash table should match D. */
26003 == d
26006 /* This needs to happen before any tsubsting. */
26012 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
26013 for the instantiation. */
26018 {
26019 /* Look up an explicit specialization, if any. */
26022 {
26025 }
26026 }
26030 /* We should never be trying to instantiate a member of a class
26031 template or partial specialization. */
26036 /* In the case of a friend template whose definition is provided
26037 outside the class, we may have too many arguments. Drop the
26038 ones we don't need. The same is true for specializations. */
26039 args = get_innermost_template_args
26043 {
26049 }
26050 else
26051 {
26055 else
26057 }
26059 /* We may be in the middle of deferred access check. Disable it now. */
26062 /* Unless an explicit instantiation directive has already determined
26063 the linkage of D, remember that a definition is available for
26064 this entity. */
26074 /* If D is a member of an explicitly instantiated class template,
26075 and no definition is available, treat it like an implicit
26076 instantiation. */
26079 {
26080 /* Leave linkage flags alone on instantiations with anonymous
26081 visibility. */
26083 {
26086 }
26088 }
26090 /* Defer all other templates, unless we have been explicitly
26091 forbidden from doing so. */
26093 template. */
26094 ! pattern_defined
26095 /* If it's OK to postpone instantiation, do so. */
26096 || defer_ok
26097 /* If this is a static data member that will be defined
26098 elsewhere, we don't want to instantiate the entire data
26099 member, but we do want to instantiate the initializer so that
26100 we can substitute that elsewhere. */
26102 /* Handle here a deleted function too, avoid generating
26103 its body (c++/61080). */
26105 {
26106 /* The definition of the static data member is now required so
26107 we must substitute the initializer. */
26111 {
26112 tree ns;
26113 tree init;
26122 args,
26125 /* If instantiating the initializer involved instantiating this
26126 again, don't call cp_finish_decl twice. */
26128 {
26129 /* Make sure the initializer is still constant, in case of
26130 circular dependency (template/instantiate6.C). */
26131 const_init
26135 LOOKUP_ONLYCONVERTING);
26136 }
26140 }
26142 /* We restore the source position here because it's used by
26143 add_pending_template. */
26149 /* [temp.explicit]
26151 The definition of a non-exported function template, a
26152 non-exported member function template, or a non-exported
26153 member function or static data member of a class template
26154 shall be present in every translation unit in which it is
26155 explicitly instantiated. */
26159 /* If we're in unevaluated context, we just wanted to get the
26160 constant value; this isn't an odr use, so don't queue
26161 a full instantiation. */
26163 /* ??? Historically, we have instantiated inline functions, even
26164 when marked as "extern template". */
26167 }
26168 else
26169 {
26174 }
26184 }
26186 /* Run through the list of templates that we wish we could
26187 instantiate, and instantiate any we can. RETRIES is the
26188 number of times we retry pending template instantiation. */
26190 void
26192 {
26196 /* Instantiating templates may trigger vtable generation. This in turn
26197 may require further template instantiations. We place a limit here
26198 to avoid infinite loop. */
26200 {
26204 "template instantiation depth exceeds maximum of %d"
26205 " instantiating %q+D, possibly from virtual table generation"
26209 /* Pretend that we defined it. */
26212 }
26214 do
26215 {
26220 {
26225 {
26227 {
26242 }
26245 }
26246 else
26247 {
26250 {
26251 instantiation
26257 }
26261 }
26264 {
26265 /* If INSTANTIATION has been instantiated, then we don't
26266 need to consider it again in the future. */
26271 }
26272 else
26273 {
26276 }
26279 }
26281 }
26285 }
26287 /* Substitute ARGVEC into T, which is a list of initializers for
26288 either base class or a non-static data member. The TREE_PURPOSEs
26289 are DECLs, and the TREE_VALUEs are the initializer values. Used by
26290 instantiate_decl. */
26292 static tree
26294 {
26299 {
26300 tree decl;
26301 tree init;
26307 {
26308 tree expr;
26309 tree arg;
26311 /* Expand the base class expansion type into separate base
26312 classes. */
26314 tf_warning_or_error,
26315 NULL_TREE);
26319 /* We'll be building separate TREE_LISTs of arguments for
26320 each base. */
26326 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
26327 expand each argument in the TREE_VALUE of t. */
26334 /* VOID_TYPE_NODE is used to indicate
26335 value-initialization. */
26336 {
26339 }
26340 else
26341 {
26342 /* Substitute parameter packs into each argument in the
26343 TREE_LIST. */
26346 {
26347 tree expanded_exprs;
26349 /* Expand the argument. */
26350 tree value;
26353 else
26354 {
26357 }
26358 expanded_exprs
26360 tf_warning_or_error,
26361 NULL_TREE);
26365 /* Prepend each of the expanded expressions to the
26366 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
26374 else
26379 }
26382 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
26383 since we built them backwards. */
26385 {
26388 }
26389 }
26390 }
26393 {
26395 {
26399 }
26400 else
26401 {
26402 tree tmp;
26417 /* If we had an initializer but it instantiated to nothing,
26418 value-initialize the object. This will only occur when
26419 the initializer was a pack expansion where the parameter
26420 packs used in that expansion were of length zero. */
26423 }
26427 {
26429 decl);
26431 }
26432 /* Look for a target constructor. */
26436 {
26439 {
26443 }
26445 }
26448 {
26450 /* Carry over the dummy TREE_TYPE node containing the source
26451 location. */
26455 }
26456 }
26457 }
26459 }
26461 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
26462 is the instantiation (which should have been created with
26463 start_enum) and ARGS are the template arguments to use. */
26465 static void
26467 {
26468 tree e;
26474 {
26475 tree value;
26476 tree decl;
26479 /* Note that in a template enum, the TREE_VALUE is the
26480 CONST_DECL, not the corresponding INTEGER_CST. */
26485 /* Give this enumeration constant the correct access. */
26488 /* Actually build the enumerator itself. Here we're assuming that
26489 enumerators can't have dependent attributes. */
26492 }
26502 }
26504 /* DECL is a FUNCTION_DECL that is a template specialization. Return
26505 its type -- but without substituting the innermost set of template
26506 arguments. So, innermost set of template parameters will appear in
26507 the type. */
26509 tree
26511 {
26512 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
26514 }
26516 /* Return truthvalue if we're processing a template different from
26517 the last one involved in diagnostics. */
26518 bool
26520 {
26522 }
26524 /* Remember current template involved in diagnostics. */
26525 void
26527 {
26529 }
26533 {
26535 }
26537 /* Return TRUE if current_function_decl is being instantiated, false
26538 otherwise. */
26540 bool
26542 {
26546 }
26548 /* [temp.param] Check that template non-type parm TYPE is of an allowable
26549 type. Return false for ok, true for disallowed. Issue error and
26550 inform messages under control of COMPLAIN. */
26552 static bool
26554 {
26565 {
26567 {
26572 }
26574 }
26581 /* A bound template template parm could later be instantiated to have a valid
26582 nontype parm type via an alias template. */
26591 {
26599 {
26600 auto_diagnostic_group d;
26604 }
26606 }
26608 {
26613 }
26616 {
26619 else
26621 type);
26622 }
26624 }
26626 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
26627 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
26629 static bool
26631 {
26632 tree scope;
26634 /* [temp.dep.type]
26636 A type is dependent if it is:
26638 -- a template parameter. Template template parameters are types
26639 for us (since TYPE_P holds true for them) so we handle
26640 them here. */
26644 /* -- a qualified-id with a nested-name-specifier which contains a
26645 class-name that names a dependent type or whose unqualified-id
26646 names a dependent type. */
26650 /* An alias template specialization can be dependent even if the
26651 resulting type is not. */
26655 /* -- a cv-qualified type where the cv-unqualified type is
26656 dependent.
26657 No code is necessary for this bullet; the code below handles
26658 cv-qualified types, and we don't want to strip aliases with
26659 TYPE_MAIN_VARIANT because of DR 1558. */
26660 /* -- a compound type constructed from any dependent type. */
26668 {
26669 tree arg_type;
26674 arg_type;
26679 /* A value-dependent noexcept-specifier makes the type dependent. */
26682 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
26683 affect overload resolution and treating it as dependent breaks
26684 things. Same for an unparsed noexcept expression. */
26690 }
26691 /* -- an array type constructed from any dependent type or whose
26692 size is specified by a constant expression that is
26693 value-dependent.
26695 We checked for type- and value-dependence of the bounds in
26696 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
26698 {
26703 }
26705 /* -- a template-id in which either the template name is a template
26706 parameter ... */
26709 /* ... or any of the template arguments is a dependent type or
26710 an expression that is type-dependent or value-dependent. */
26712 && (any_dependent_template_arguments_p
26716 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
26717 dependent; if the argument of the `typeof' expression is not
26718 type-dependent, then it should already been have resolved. */
26724 /* A template argument pack is dependent if any of its packed
26725 arguments are. */
26727 {
26733 }
26735 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
26736 be template parameters. */
26743 /* The standard does not specifically mention types that are local
26744 to template functions or local classes, but they should be
26745 considered dependent too. For example:
26747 template <int I> void f() {
26748 enum E { a = I };
26749 S<sizeof (E)> s;
26750 }
26752 The size of `E' cannot be known until the value of `I' has been
26753 determined. Therefore, `E' must be considered dependent. */
26757 /* Don't use type_dependent_expression_p here, as it can lead
26758 to infinite recursion trying to determine whether a lambda
26759 nested in a lambda is dependent (c++/47687). */
26763 && (any_dependent_template_arguments_p
26767 /* Other types are non-dependent. */
26769 }
26771 /* Returns TRUE if TYPE is dependent, in the sense of
26772 [temp.dep.type]. Note that a NULL type is considered dependent. */
26774 bool
26776 {
26777 /* If there are no template parameters in scope, then there can't be
26778 any dependent types. */
26780 {
26781 /* If we are not processing a template, then nobody should be
26782 providing us with a dependent type. */
26786 }
26788 /* If the type is NULL, we have not computed a type for the entity
26789 in question; in that case, the type is dependent. */
26793 /* Erroneous types can be considered non-dependent. */
26797 /* If we have not already computed the appropriate value for TYPE,
26798 do so now. */
26800 {
26803 }
26806 }
26808 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
26809 lookup. In other words, a dependent type that is not the current
26810 instantiation. */
26812 bool
26814 {
26817 }
26819 /* T is a SCOPE_REF. Return whether it represents a non-static member of
26820 an unknown base of 'this' (and is therefore instantiation-dependent). */
26822 static bool
26824 {
26841 }
26843 /* T is a SCOPE_REF; return whether we need to consider it
26844 instantiation-dependent so that we can check access at instantiation
26845 time even though we know which member it resolves to. */
26847 static bool
26849 {
26856 else
26858 }
26860 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
26861 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
26862 expression. */
26864 /* Note that this predicate is not appropriate for general expressions;
26865 only constant expressions (that satisfy potential_constant_expression)
26866 can be tested for value dependence. */
26868 bool
26870 {
26874 /* A type-dependent expression is also value-dependent. */
26879 {
26881 /* A dependent member function of the current instantiation. */
26885 /* A dependent member function of the current instantiation. */
26892 /* A name that has not been looked up -- must be dependent. */
26896 /* A non-type template parm. */
26900 /* A non-type template parm. */
26906 /* A constant with literal type and is initialized
26907 with an expression that is value-dependent. */
26909 /* FIXME cp_finish_decl doesn't fold reference initializers. */
26913 {
26916 /* __PRETTY_FUNCTION__ inside a template function is dependent
26917 on the name of the function. */
26919 /* It might be used in a template, but not a template
26920 function, in which case its DECL_VALUE_EXPR will be
26921 "top level". */
26924 }
26933 /* These expressions are value-dependent if the type to which
26934 the cast occurs is dependent or the expression being casted
26935 is value-dependent. */
26936 {
26942 /* A functional cast has a list of operands. */
26945 {
26946 /* If there are no operands, it must be an expression such
26947 as "int()". This should not happen for aggregate types
26948 because it would form non-constant expressions. */
26953 }
26959 }
26964 /* FALLTHRU */
26967 /* A `sizeof' expression is value-dependent if the operand is
26968 type-dependent or is a pack expansion. */
26977 /* An 'encode' expression is value-dependent if the operand is
26978 type-dependent. */
26987 /* All instantiation-dependent expressions should also be considered
26988 value-dependent. */
26996 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
26997 is value-dependent. */
26998 {
27007 }
27010 {
27027 }
27038 {
27042 }
27045 /* Treat all requires-expressions as value-dependent so
27046 we don't try to fold them. */
27053 {
27060 {
27062 /* In a call to a constexpr member function, look through the
27063 implicit ADDR_EXPR on the object argument so that it doesn't
27064 cause the call to be considered value-dependent. We also
27065 look through it in potential_constant_expression. */
27072 }
27074 }
27080 {
27082 tree val;
27089 }
27092 /* Treat a GNU statement expression as dependent to avoid crashing
27093 under instantiate_non_dependent_expr; it can't be constant. */
27097 /* A constant expression is value-dependent if any subexpression is
27098 value-dependent. */
27100 {
27107 {
27111 {
27114 /* In some cases, some of the operands may be missing.
27115 (For example, in the case of PREDECREMENT_EXPR, the
27116 amount to increment by may be missing.) That doesn't
27117 make the expression dependent. */
27120 }
27121 }
27125 }
27127 }
27129 /* The expression is not value-dependent. */
27131 }
27133 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
27134 [temp.dep.expr]. Note that an expression with no type is
27135 considered dependent. Other parts of the compiler arrange for an
27136 expression with type-dependent subexpressions to have no type, so
27137 this function doesn't have to be fully recursive. */
27139 bool
27141 {
27150 /* An unresolved name is always dependent. */
27156 /* A lambda-expression in template context is dependent. dependent_type_p is
27157 true for a lambda in the scope of a class or function template, but that
27158 doesn't cover all template contexts, like a default template argument. */
27162 /* A fold expression is type-dependent. */
27169 /* Some expression forms are never type-dependent. */
27182 /* The types of these expressions depends only on the type to which
27183 the cast occurs. */
27192 /* The types of these expressions depends only on the type created
27193 by the expression. */
27196 {
27197 /* For NEW_EXPR tree nodes created inside a template, either
27198 the object type itself or a TREE_LIST may appear as the
27199 operand 1. */
27202 /* This is an array type. We need to check array dimensions
27203 as well. */
27205 || value_dependent_expression_p
27207 /* Array type whose dimension has to be deduced. */
27211 else
27213 }
27216 {
27220 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
27221 contains an identifier associated by name lookup with one or more
27222 declarations declared with a dependent type, or...a
27223 nested-name-specifier or qualified-id that names a member of an
27224 unknown specialization. */
27227 }
27237 {
27238 tree elt;
27242 {
27245 }
27247 }
27249 /* A static data member of the current instantiation with incomplete
27250 array type is type-dependent, as the definition and specializations
27251 can have different bounds. */
27258 /* An array of unknown bound depending on a variadic parameter, eg:
27260 template<typename... Args>
27261 void foo (Args... args)
27262 {
27263 int arr[] = { args... };
27264 }
27266 template<int... vals>
27267 void bar ()
27268 {
27269 int arr[] = { vals... };
27270 }
27272 If the array has no length and has an initializer, it must be that
27273 we couldn't determine its length in cp_complete_array_type because
27274 it is dependent. */
27282 /* A function or variable template-id is type-dependent if it has any
27283 dependent template arguments. */
27287 {
27288 /* Consider the innermost template arguments, since those are the ones
27289 that come from the template-id; the template arguments for the
27290 enclosing class do not make it type-dependent unless they are used in
27291 the type of the decl. */
27293 && (any_dependent_template_arguments_p
27296 }
27298 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
27299 type-dependent. Checking this is important for functions with auto return
27300 type, which looks like a dependent type. */
27309 {
27313 }
27315 /* Always dependent, on the number of arguments if nothing else. */
27320 {
27325 {
27331 }
27332 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
27336 /* CO_AWAIT/YIELD_EXPR with unknown type is always dependent. */
27342 {
27347 }
27350 {
27357 }
27366 }
27368 /* The type of a non-type template parm declared with a placeholder type
27369 depends on the corresponding template argument, even though
27370 placeholders are not normally considered dependent. */
27377 /* Dependent type attributes might not have made it from the decl to
27378 the type yet. */
27384 }
27386 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
27387 type-dependent if the expression refers to a member of the current
27388 instantiation and the type of the referenced member is dependent, or the
27389 class member access expression refers to a member of an unknown
27390 specialization.
27392 This function returns true if the OBJECT in such a class member access
27393 expression is of an unknown specialization. */
27395 bool
27397 {
27398 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
27399 dependent. */
27404 }
27406 /* walk_tree callback function for instantiation_dependent_expression_p,
27407 below. Returns non-zero if a dependent subexpression is found. */
27409 static tree
27412 {
27414 {
27415 /* We don't have to worry about decltype currently because decltype
27416 of an instantiation-dependent expr is a dependent type. This
27417 might change depending on the resolution of DR 1172. */
27420 }
27423 {
27424 /* Don't treat an argument list as dependent just because it has no
27425 TREE_TYPE. */
27436 /* We'll check value-dependence separately. */
27439 /* Handle expressions with type operands. */
27444 {
27449 {
27452 else
27453 {
27456 }
27457 }
27459 }
27463 /* In a template, finish_class_member_access_expr creates a
27464 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
27465 type-dependent, so that we can check access control at
27466 instantiation time (PR 42277). See also Core issue 1273. */
27473 else
27476 /* Treat statement-expressions as dependent. */
27480 /* Treat requires-expressions as dependent. */
27485 /* Treat concept checks as dependent. */
27491 /* Treat concept checks as dependent. */
27503 }
27507 else
27509 }
27511 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
27512 sense defined by the ABI:
27514 "An expression is instantiation-dependent if it is type-dependent
27515 or value-dependent, or it has a subexpression that is type-dependent
27516 or value-dependent."
27518 Except don't actually check value-dependence for unevaluated expressions,
27519 because in sizeof(i) we don't care about the value of i. Checking
27520 type-dependence will in turn check value-dependence of array bounds/template
27521 arguments as needed. */
27523 bool
27525 {
27526 tree result;
27537 }
27539 /* As above, but also check value-dependence of the expression as a whole. */
27541 bool
27543 {
27545 || (processing_template_decl
27548 }
27550 /* Like type_dependent_expression_p, but it also works while not processing
27551 a template definition, i.e. during substitution or mangling. */
27553 bool
27555 {
27561 }
27563 /* Returns TRUE if ARGS contains a type-dependent expression. */
27565 bool
27567 {
27569 tree arg;
27572 {
27575 }
27577 }
27579 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
27580 expressions) contains any type-dependent expressions. */
27582 bool
27584 {
27590 }
27592 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
27593 expressions) contains any value-dependent expressions. */
27595 bool
27597 {
27603 }
27605 /* Returns TRUE if the ARG (a template argument) is dependent. */
27607 bool
27609 {
27613 /* Assume a template argument that was wrongly written by the user
27614 is dependent. This is consistent with what
27615 any_dependent_template_arguments_p [that calls this function]
27616 does. */
27626 {
27629 /* A member template of a dependent class is not necessarily
27630 type-dependent, but it is a dependent template argument because it
27631 will be a member of an unknown specialization to that template. */
27634 }
27636 {
27640 {
27643 }
27646 }
27649 else
27651 }
27653 /* Returns true if ARGS (a collection of template arguments) contains
27654 any types that require structural equality testing. */
27656 bool
27658 {
27668 {
27671 {
27677 {
27678 /* Look inside the argument pack. */
27681 }
27684 {
27697 }
27698 }
27699 }
27702 }
27704 /* Returns true if ARGS (a collection of template arguments) contains
27705 any dependent arguments. */
27707 bool
27709 {
27719 {
27724 }
27727 }
27729 /* Returns true if ARGS contains any errors. */
27731 bool
27733 {
27741 {
27744 else
27746 }
27752 {
27757 }
27760 }
27762 /* Returns TRUE if the template TMPL is type-dependent. */
27764 bool
27766 {
27768 {
27773 }
27775 /* Template template parameters are dependent. */
27779 /* So are names that have not been looked up. */
27783 }
27785 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
27787 bool
27789 {
27792 }
27794 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
27795 are dependent. */
27797 bool
27799 {
27806 {
27831 {
27835 }
27839 {
27843 {
27849 /* If this loop has a class iterator with != comparison
27850 with increment other than i++/++i/i--/--i, make sure the
27851 increment is constant. */
27854 {
27857 else
27861 }
27862 }
27863 }
27864 }
27867 }
27869 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
27870 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
27871 no such TYPE can be found. Note that this function peers inside
27872 uninstantiated templates and therefore should be used only in
27873 extremely limited situations. ONLY_CURRENT_P restricts this
27874 peering to the currently open classes hierarchy (which is required
27875 when comparing types). */
27877 tree
27879 {
27880 tree scope;
27881 tree name;
27882 tree decl;
27884 tree pushed_scope;
27885 tree result;
27890 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
27893 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
27894 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of a
27895 TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL
27896 representing the typedef. In that case TYPE_IDENTIFIER (type) is
27897 not the non-qualified identifier of the TYPENAME_TYPE anymore.
27898 So by getting the TYPE_IDENTIFIER of the _main declaration_ of
27899 the TYPENAME_TYPE instead, we avoid messing up with a possible
27900 typedef variant case. */
27903 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
27904 it first before we can figure out what NAME refers to. */
27906 {
27908 /* Given a class template A with a dependent base with nested type C,
27909 typedef typename A::C::C C will land us here, as trying to resolve
27910 the initial A::C leads to the local C typedef, which leads back to
27911 A::C::C. So we break the recursion now. */
27913 else
27915 }
27916 /* If we don't know what SCOPE refers to, then we cannot resolve the
27917 TYPENAME_TYPE. */
27920 /* If this is a typedef, we don't want to look inside (c++/11987). */
27923 /* If SCOPE isn't the template itself, it will not have a valid
27924 TYPE_FIELDS list. */
27926 /* scope is either the template itself or a compatible instantiation
27927 like X<T>, so look up the name in the original template. */
27929 /* If scope has no fields, it can't be a current instantiation. Check this
27930 before currently_open_class to avoid infinite recursion (71515). */
27933 /* If the SCOPE is not the current instantiation, there's no reason
27934 to look inside it. */
27937 /* Enter the SCOPE so that name lookup will be resolved as if we
27938 were in the class definition. In particular, SCOPE will no
27939 longer be considered a dependent type. */
27941 /* Look up the declaration. */
27943 tf_warning_or_error);
27947 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
27948 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
27954 {
27958 }
27961 {
27962 /* Obtain the template and the arguments. */
27965 {
27966 /* We get here with a plain identifier because a previous tentative
27967 parse of the nested-name-specifier as part of a ptr-operator saw
27968 ::template X<A>. The use of ::template is necessary in a
27969 ptr-operator, but wrong in a declarator-id.
27971 [temp.names]: In a qualified-id of a declarator-id, the keyword
27972 template shall not appear at the top level. */
27976 }
27978 /* Instantiate the template. */
27984 }
27986 /* Leave the SCOPE. */
27990 /* If we failed to resolve it, return the original typename. */
27994 /* If lookup found a typename type, resolve that too. */
27996 {
27997 /* Ill-formed programs can cause infinite recursion here, so we
27998 must catch that. */
28002 }
28004 /* Qualify the resulting type. */
28010 }
28012 /* EXPR is an expression which is not type-dependent. Return a proxy
28013 for EXPR that can be used to compute the types of larger
28014 expressions containing EXPR. */
28016 tree
28018 {
28020 tree inner_expr;
28022 /* When checking, try to get a constant value for all non-dependent
28023 expressions in order to expose bugs in *_dependent_expression_p
28024 and constexpr. This can affect code generation, see PR70704, so
28025 only do this for -fchecking=2. */
28028 /* Don't do this during nsdmi parsing as it can lead to
28029 unexpected recursive instantiations. */
28031 /* Don't do this during concept processing either and for
28032 the same reason. */
28038 /* Preserve OVERLOADs; the functions must be available to resolve
28039 types. */
28050 /* There is no need to return a proxy for a variable or enumerator. */
28053 /* Preserve string constants; conversions from string constants to
28054 "char *" are allowed, even though normally a "const char *"
28055 cannot be used to initialize a "char *". */
28058 /* Preserve void and arithmetic constants, as an optimization -- there is no
28059 reason to create a new node. */
28064 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
28065 There is at least one place where we want to know that a
28066 particular expression is a throw-expression: when checking a ?:
28067 expression, there are special rules if the second or third
28068 argument is a throw-expression. */
28072 /* Don't wrap an initializer list, we need to be able to look inside. */
28076 /* Don't wrap a dummy object, we need to be able to test for it. */
28095 /* If the type is unknown, it can't really be non-dependent */
28098 /* Otherwise, build a NON_DEPENDENT_EXPR. */
28101 }
28103 /* ARGS is a vector of expressions as arguments to a function call.
28104 Replace the arguments with equivalent non-dependent expressions.
28105 This modifies ARGS in place. */
28107 void
28109 {
28111 tree arg;
28114 {
28118 }
28119 }
28121 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
28122 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
28123 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
28125 static tree
28127 {
28142 }
28144 tree
28146 {
28148 }
28150 tree
28152 {
28154 }
28156 /* Return a C++17 deduction placeholder for class template TMPL. */
28158 tree
28160 {
28163 /* Our canonical type depends on the placeholder. */
28166 }
28168 /* True iff T is a C++17 class template deduction placeholder. */
28170 bool
28172 {
28174 }
28176 /* Make a "constrained auto" type-specifier. This is an auto or
28177 decltype(auto) type with constraints that must be associated after
28178 deduction. The constraint is formed from the given concept CON
28179 and its optional sequence of template arguments ARGS.
28181 TYPE must be the result of make_auto_type or make_decltype_auto_type. */
28183 static tree
28185 {
28186 /* Build the constraint. */
28198 /* Our canonical type depends on the constraint. */
28201 /* Attach the constraint to the type declaration. */
28203 }
28205 /* Make a "constrained auto" type-specifier. */
28207 tree
28209 {
28212 }
28214 /* Make a "constrained decltype(auto)" type-specifier. */
28216 tree
28218 {
28221 }
28223 /* Returns true if the placeholder type constraint T has any dependent
28224 (explicit) template arguments. */
28226 static bool
28228 {
28233 {
28236 }
28243 }
28245 /* Build and return a concept definition. Like other templates, the
28246 CONCEPT_DECL node is wrapped by a TEMPLATE_DECL. This returns the
28247 the TEMPLATE_DECL. */
28249 tree
28251 {
28257 /* A concept-definition shall not have associated constraints. */
28259 {
28262 }
28264 /* A concept-definition shall appear in namespace scope. Templates
28265 aren't allowed in block scope, so we only need to check for class
28266 scope. */
28268 {
28271 }
28273 /* Initially build the concept declaration; its type is bool. */
28280 /* Push the enclosing template. */
28282 }
28284 /* Given type ARG, return std::initializer_list<ARG>. */
28286 static tree
28288 {
28292 {
28296 "deducing from brace-enclosed initializer list"
28300 }
28306 }
28308 /* Replace auto in TYPE with std::initializer_list<auto>. */
28310 static tree
28312 {
28319 }
28321 /* Hash traits for hashing possibly constrained 'auto'
28322 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
28325 {
28328 };
28330 /* Hash the 'auto' T. */
28332 inline hashval_t
28334 {
28336 /* Matching constrained-type-specifiers denote the same template
28337 parameter, so hash the constraint. */
28339 else
28340 /* But unconstrained autos are all separate, so just hash the pointer. */
28342 }
28344 /* Compare two 'auto's. */
28348 {
28355 /* Two unconstrained autos are distinct. */
28360 }
28362 /* for_each_template_parm callback for extract_autos: if t is a (possibly
28363 constrained) auto, add it to the vector. */
28365 static int
28367 {
28370 {
28371 /* All the autos were built with index 0; fix that up now. */
28375 /* If this is a repeated constrained-type-specifier, use the index we
28376 chose before. */
28378 else
28379 {
28380 /* Otherwise this is new, so use the current count. */
28383 }
28385 }
28387 /* Always keep walking. */
28389 }
28391 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
28392 says they can appear anywhere in the type. */
28394 static tree
28396 {
28405 {
28410 }
28413 }
28415 /* The stem for deduction guide names. */
28418 /* Return the name for a deduction guide for class template TMPL. */
28420 tree
28422 {
28433 }
28435 /* True if NAME is the name of a deduction guide. */
28437 bool
28439 {
28443 }
28445 /* True if FN is a deduction guide. */
28447 bool
28449 {
28454 }
28456 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
28458 bool
28460 {
28467 }
28469 /* True if FN is a guide generated from a constructor template. */
28471 bool
28473 {
28481 }
28483 /* True if FN is an aggregate initialization guide or the copy deduction
28484 guide. */
28486 bool
28488 {
28492 /* Explicitly declared. */
28495 /* Derived from a constructor. */
28498 }
28500 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
28501 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
28502 template parameter types. Note that the handling of template template
28503 parameters relies on current_template_parms being set appropriately for the
28504 new template. */
28506 static tree
28509 {
28515 tree newtype;
28518 {
28522 }
28523 else
28524 {
28527 {
28528 // Substitute once to fix references to other template parameters.
28531 // Now substitute again to reduce the level of the auto.
28534 }
28535 else
28538 }
28540 tree newdecl
28545 tree newidx;
28548 {
28557 else
28561 {
28566 // First create a copy (ttargs) of tsubst_args with an
28567 // additional level for the template template parameter's own
28568 // template parameters (ttparms).
28569 tree ttparms = (INNERMOST_TEMPLATE_PARMS
28577 // Substitute ttargs into ttparms to fix references to
28578 // other template parameters.
28581 // Now substitute again with args based on tparms, to reduce
28582 // the level of the ttparms.
28585 complain);
28586 // Finally, tack the adjusted parms onto tparms.
28588 current_template_parms);
28590 }
28591 }
28592 else
28593 {
28595 tree newconst
28607 }
28610 }
28612 /* As rewrite_template_parm, but for the whole TREE_LIST representing a
28613 template parameter. */
28615 static tree
28618 {
28633 }
28635 /* Returns a C++17 class deduction guide template based on the constructor
28636 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
28637 guide, REFERENCE_TYPE for an implicit copy/move guide, or TREE_LIST for an
28638 aggregate initialization guide. OUTER_ARGS are the template arguments
28639 for the enclosing scope of the class. */
28641 static tree
28643 {
28647 location_t loc;
28651 {
28655 }
28658 {
28660 {
28664 else
28666 }
28669 else
28679 }
28680 else
28681 {
28685 fn_tmpl
28693 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
28694 fully specialized args for the enclosing class. Strip those off, as
28695 the deduction guide won't have those template parameters. */
28698 /* Discard the 'this' parameter. */
28706 {
28709 /* For a member template constructor, we need to flatten the two
28710 template parameter lists into one, and then adjust the function
28711 signature accordingly. This gets...complicated. */
28714 /* For a member template we should have two levels of parms/args, one
28715 for the class and one for the constructor. We stripped
28716 specialized args for further enclosing classes above. */
28720 /* Template args for translating references to the two-level template
28721 parameters into references to the one-level template parameters we
28722 are creating. */
28727 /* Template parms for the constructor template. */
28730 /* Template parms for the class template. */
28734 /* Template parms for the deduction guide start as a copy of the
28735 template parms for the class. We set current_template_parms for
28736 lookup_template_class_1. */
28742 /* Now we need to rewrite the constructor parms to append them to the
28743 class parms. */
28745 {
28749 tree newelt
28755 }
28757 /* Now we have a final set of template parms to substitute into the
28758 function signature. */
28765 {
28767 /* FIXME: We'd like to avoid substituting outer template
28768 arguments into the constraint ahead of time, but the
28769 construction of tsubst_args assumes that outer arguments
28770 are already substituted in. */
28773 }
28775 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped if
28776 cp_unevaluated_operand. */
28777 cp_evaluated ev;
28780 }
28781 else
28782 {
28783 /* Substitute in the same arguments to rewrite class members into
28784 references to members of an unknown specialization. */
28785 cp_evaluated ev;
28789 {
28791 /* FIXME: As above. */
28794 }
28795 }
28800 }
28803 {
28804 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
28808 }
28812 FUNCTION_DECL,
28827 }
28829 /* Add to LIST the member types for the reshaped initializer CTOR. */
28831 static tree
28833 {
28837 {
28841 {
28847 }
28851 /* Give the trailing pack expansion parameter a default argument to
28852 match aggregate initialization behavior, even if we deduce the
28853 length of the pack separately to more than we have initializers. */
28855 /* if ei is of array type and xi is a braced-init-list or string literal,
28856 Ti is an rvalue reference to the declared type of ei */
28861 {
28863 ftype = cp_build_qualified_type
28865 ftype = (cp_build_reference_type
28867 }
28869 }
28872 }
28874 /* Return whether ETYPE is, or is derived from, a specialization of TMPL. */
28876 static bool
28878 {
28884 tree tparms = (INNERMOST_TEMPLATE_PARMS
28891 }
28895 /* Return a C++20 aggregate deduction candidate for TYPE initialized from
28896 INIT. */
28898 static tree
28900 {
28908 {
28914 }
28916 /* We might be creating a guide for a class member template, e.g.,
28918 template<typename U> struct A {
28919 template<typename T> struct B { T t; };
28920 };
28922 At this point, A will have been instantiated. Below, we need to
28923 use both A<U>::B<T> (TEMPLATE_TYPE) and A<int>::B<T> (TYPE) types. */
28924 const bool member_template_p
28928 tree template_type = (member_template_p
28934 /* No aggregate candidate for copy-initialization. */
28936 {
28940 }
28942 /* If we encounter a problem, we just won't add the candidate. */
28947 {
28952 /* If we're creating a deduction guide for a member class template,
28953 we've used the original template pattern type for the reshape_init
28954 above; this is done because we want PARMS to be a template parameter
28955 type, something that can be deduced when used as a function template
28956 parameter. At this point the outer class template has already been
28957 partially instantiated (we deferred the deduction until the enclosing
28958 scope is non-dependent). Therefore we have to partially instantiate
28959 PARMS, so that its template level is properly reduced and we don't get
28960 mismatches when deducing types using the guide with PARMS. */
28963 }
28965 {
28968 len;
28970 {
28976 }
28977 }
28978 else
28979 /* Aggregate initialization doesn't apply to an initializer expression. */
28983 {
28989 }
28992 }
28994 /* UGUIDES are the deduction guides for the underlying template of alias
28995 template TMPL; adjust them to be deduction guides for TMPL. */
28997 static tree
28999 {
29000 /* [over.match.class.deduct]: When resolving a placeholder for a deduced
29001 class type (9.2.8.2) where the template-name names an alias template A,
29002 the defining-type-id of A must be of the form
29004 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
29006 as specified in 9.2.8.2. The guides of A are the set of functions or
29007 function templates formed as follows. For each function or function
29008 template f in the guides of the template named by the simple-template-id
29009 of the defining-type-id, the template arguments of the return type of f
29010 are deduced from the defining-type-id of A according to the process in
29011 13.10.2.5 with the exception that deduction does not fail if not all
29012 template arguments are deduced. Let g denote the result of substituting
29013 these deductions into f. If substitution succeeds, form a function or
29014 function template f' with the following properties and add it to the set
29015 of guides of A:
29017 * The function type of f' is the function type of g.
29019 * If f is a function template, f' is a function template whose template
29020 parameter list consists of all the template parameters of A (including
29021 their default template arguments) that appear in the above deductions or
29022 (recursively) in their default template arguments, followed by the
29023 template parameters of f that were not deduced (including their default
29024 template arguments), otherwise f' is not a function template.
29026 * The associated constraints (13.5.2) are the conjunction of the
29027 associated constraints of g and a constraint that is satisfied if and only
29028 if the arguments of A are deducible (see below) from the return type.
29030 * If f is a copy deduction candidate (12.4.1.8), then f' is considered to
29031 be so as well.
29033 * If f was generated from a deduction-guide (12.4.1.8), then f' is
29034 considered to be so as well.
29036 * The explicit-specifier of f' is the explicit-specifier of g (if
29037 any). */
29039 /* This implementation differs from the above in two significant ways:
29041 1) We include all template parameters of A, not just some.
29042 2) The added constraint is same_type instead of deducible.
29044 I believe that while it's probably possible to construct a testcase that
29045 behaves differently with this simplification, it should have the same
29046 effect for real uses. Including all template parameters means that we
29047 deduce all parameters of A when resolving the call, so when we're in the
29048 constraint we don't need to deduce them again, we can just check whether
29049 the deduction produced the desired result. */
29058 {
29065 {
29069 /* Deduce template arguments for f from the type-id of A. */
29077 /* The number of parms for f' is the number of parms for A plus
29078 non-deduced parms of f. */
29086 /* First copy over the parms of A. */
29089 /* Now rewrite the non-deduced parms of f. */
29092 {
29100 }
29103 /* Substitute the deduced arguments plus the rewritten template
29104 parameters into f to get g. This covers the type, copyness,
29105 guideness, and explicit-specifier. */
29106 tree g;
29107 {
29108 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped
29109 if cp_unevaluated_operand. */
29110 cp_evaluated ev;
29112 }
29123 /* Substitute the associated constraints. */
29130 /* Add a constraint that the return type matches the instantiation of
29131 A with the same template arguments. */
29134 /* FIXME this should mean they don't compare as equivalent. */
29136 {
29139 }
29142 {
29145 }
29146 }
29147 else
29148 {
29149 /* For a non-template deduction guide, if the arguments of A aren't
29150 deducible from the return type, don't add the candidate. */
29158 }
29161 }
29164 }
29166 /* Return artificial deduction guides built from the constructors of class
29167 template TMPL. */
29169 static tree
29171 {
29176 {
29179 }
29184 {
29185 /* Skip inherited constructors. */
29191 }
29193 /* Add implicit default constructor deduction guide. */
29195 {
29197 complain);
29199 }
29201 /* Add copy guide. */
29202 {
29205 complain);
29207 }
29210 }
29214 /* Return the non-aggregate deduction guides for deducible template TMPL. The
29215 aggregate candidate is added separately because it depends on the
29216 initializer. Set ANY_DGUIDES_P if we find a non-implicit deduction
29217 guide. */
29219 static tree
29221 {
29224 {
29228 complain);
29229 }
29230 else
29231 {
29237 else
29239 }
29241 /* Cache the deduction guides for a template. We also remember the result of
29242 lookup, and rebuild everything if it changes; should be very rare. */
29246 {
29250 }
29251 else
29252 {
29255 }
29260 else
29261 {
29265 }
29269 }
29271 /* Return whether TMPL is a (class template argument-) deducible template. */
29273 bool
29275 {
29276 /* A deducible template is either a class template or is an alias template
29277 whose defining-type-id is of the form
29279 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
29281 where the nested-name-specifier (if any) is non-dependent and the
29282 template-name of the simple-template-id names a deducible template. */
29293 }
29295 /* Deduce template arguments for the class template placeholder PTYPE for
29296 template TMPL based on the initializer INIT, and return the resulting
29297 type. */
29299 static tree
29302 {
29303 /* We should have handled this in the caller. */
29307 /* Wait until the enclosing scope is non-dependent. */
29312 /* Initializing one placeholder from another. */
29322 /* Look through alias templates that just rename another template. */
29325 {
29329 }
29331 {
29336 }
29338 /* Wait until the initializer is non-dependent. */
29352 {
29357 {
29358 /* As an exception, the first phase in 16.3.1.7 (considering the
29359 initializer list as a single argument) is omitted if the
29360 initializer list consists of a single expression of type cv U,
29361 where U is a specialization of C or a class derived from a
29362 specialization of C. */
29366 }
29369 else
29371 }
29374 else
29377 /* Do this now to avoid problems with erroneous args later on. */
29387 /* Prune explicit deduction guides in copy-initialization context (but
29388 not copy-list-initialization). */
29391 {
29397 {
29398 /* Found a nonconverting guide, prune the candidates. */
29405 }
29406 }
29414 /* If this is list-initialization and the class has a list constructor, first
29415 try deducing from the list as a single argument, as [over.match.list]. */
29419 {
29423 }
29425 {
29429 {
29430 /* That didn't work, now try treating the list as a sequence of
29431 arguments. */
29434 }
29435 }
29438 {
29440 " of %qT, as it has no non-explicit deduction guides or "
29443 }
29445 {
29449 }
29455 {
29457 {
29463 }
29465 }
29466 /* [over.match.list]/1: In copy-list-initialization, if an explicit
29467 constructor is chosen, the initialization is ill-formed. */
29469 {
29471 {
29473 {
29474 // TODO: Pass down location from cp_finish_decl.
29476 "explicit deduction guide selected in "
29481 }
29483 }
29484 }
29486 /* If CTAD succeeded but the type doesn't have any explicit deduction
29487 guides, this deduction might not be what the user intended. */
29489 {
29493 "%qT may not intend to support class template argument "
29497 }
29501 }
29503 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
29504 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
29505 The CONTEXT determines the context in which auto deduction is performed
29506 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
29508 OUTER_TARGS is used during template argument deduction (context == adc_unify)
29509 to properly substitute the result. It's also used in the adc_unify and
29510 adc_requirement contexts to communicate the the necessary template arguments
29511 to satisfaction. OUTER_TARGS is ignored in other contexts.
29513 For partial-concept-ids, extra args may be appended to the list of deduced
29514 template arguments prior to determining constraint satisfaction. */
29516 tree
29520 {
29526 /* Defining a subset of type-dependent expressions that we can deduce
29527 from ahead of time isn't worth the trouble. */
29530 /* Similarly, we can't deduce from another undeduced decl. */
29534 /* We may be doing a partial substitution, but we still want to replace
29535 auto_node. */
29539 /* C++17 class template argument deduction. */
29543 /* Nothing we can do with this, even in deduction context. */
29546 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
29547 with either a new invented type template parameter U or, if the
29548 initializer is a braced-init-list (8.5.4), with
29549 std::initializer_list<U>. */
29551 {
29556 else
29557 {
29559 {
29563 "for deduction to %<std::initializer_list%>, use copy-"
29565 }
29567 }
29568 }
29574 {
29575 /* We don't recurse here because we can't deduce from a nested
29576 initializer_list. */
29580 }
29581 else
29584 tree targs;
29589 {
29590 /* [dcl.struct.bind]/1 - if decomposition declaration has no ref-qualifiers
29591 and initializer has array type, deduce cv-qualified array type. */
29594 }
29596 {
29610 /* FIXME: These errors ought to be diagnosed at parse time. */
29612 {
29616 }
29618 {
29622 }
29623 }
29624 else
29625 {
29630 tree tparms;
29634 else
29635 {
29639 }
29643 DEDUCE_CALL,
29646 {
29648 /* Try again at instantiation time. */
29652 /* If type is error_mark_node a diagnostic must have been
29653 emitted by now. Also, having a mention to '<type error>'
29654 in the diagnostic is not really useful to the user. */
29655 {
29658 && (auto_node
29662 else
29665 DEDUCE_CALL,
29667 }
29669 }
29670 }
29672 /* Check any placeholder constraints against the deduced type. */
29676 {
29678 {
29683 /* If the constraint is dependent, we need to wait until
29684 instantiation time to resolve the placeholder. */
29687 }
29692 && current_function_decl
29698 /* HACK: Compensate for callers not always communicating all levels of
29699 outer template arguments by filling in the outermost missing levels
29700 with dummy levels before checking satisfaction. We'll still crash
29701 if the constraint depends on a template argument belonging to one of
29702 these missing levels, but this hack otherwise allows us to handle a
29703 large subset of possible constraints (including all non-dependent
29704 constraints). */
29707 {
29712 }
29715 {
29717 {
29718 auto_diagnostic_group d;
29720 {
29738 }
29740 }
29742 }
29743 }
29746 /* The outer template arguments are already substituted into type
29753 }
29755 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
29756 result. */
29758 tree
29760 {
29762 {
29765 }
29769 {
29770 /* In an abbreviated function template we didn't know we were dealing
29771 with a function template when we saw the auto return type, so rebuild
29772 the return type using an auto with the correct level. */
29777 auto_vec);
29778 /* Also rebuild the constraint info in terms of the new auto. */
29786 }
29788 }
29790 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
29791 'decltype(auto)' or a deduced class template. */
29793 bool
29795 {
29800 else
29802 }
29804 /* for_each_template_parm callback for type_uses_auto. */
29806 int
29808 {
29810 }
29812 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
29813 a use of `auto'. Returns NULL_TREE otherwise. */
29815 tree
29817 {
29821 {
29822 /* The Concepts TS allows multiple autos in one type-specifier; just
29823 return the first one we find, do_auto_deduction will collect all of
29824 them. */
29828 else
29830 }
29831 else
29833 }
29835 /* Report ill-formed occurrences of auto types in ARGUMENTS. If
29836 concepts are enabled, auto is acceptable in template arguments, but
29837 only when TEMPL identifies a template class. Return TRUE if any
29838 such errors were reported. */
29840 bool
29842 {
29843 /* If there were previous errors, nevermind. */
29847 /* If TMPL is an identifier, we're parsing and we can't tell yet
29848 whether TMPL is supposed to be a type, a function or a variable.
29849 We'll only be able to tell during template substitution, so we
29850 expect to be called again then. If concepts are enabled and we
29851 know we have a type, we're ok. */
29859 /* Quickly search for any occurrences of auto; usually there won't
29860 be any, and then we'll avoid allocating the vector. */
29868 {
29873 }
29876 }
29878 /* Recursively walk over && expressions searching for EXPR. Return a reference
29879 to that expression. */
29882 {
29886 {
29891 }
29893 }
29895 /* Convert the generic type parameters in PARM that match the types given in the
29896 range [START_IDX, END_IDX) from the current_template_parms into generic type
29897 packs. */
29899 tree
29901 {
29912 {
29913 /* Create a distinct parameter pack type from the current parm and add it
29914 to the replacement args to tsubst below into the generic function
29915 parameter. */
29929 /* Replace the current template parameter with new pack. */
29932 /* Surgically adjust the associated constraint of adjusted parameter
29933 and it's corresponding contribution to the current template
29934 requirements. */
29936 {
29942 /* If there was a constraint, we also need to replace that in
29943 the template requirements, which we've already built. */
29947 }
29948 }
29954 /* If there are more levels then build up the replacement with the outer
29955 template parms. */
29959 replacement);
29962 }
29964 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
29965 0..N-1. */
29967 void
29969 {
29972 integer_type_node,
29973 NULL_TREE),
29977 CP_BUILT_IN_INTEGER_PACK);
29978 }
29980 /* Walk the decl or type specialization table calling FN on each
29981 entry. */
29983 void
29987 {
29993 }
29995 /* Lookup the specialization of *ELT, in the decl or type
29996 specialization table. Return the SPEC that's already there, or
29997 NULL if nothing. */
29999 tree
30001 {
30011 }
30013 /* Return flags encoding whether SPEC is on the instantiation and/or
30014 specialization lists of TMPL. */
30016 unsigned
30018 {
30024 {
30027 }
30032 /* Only need to search if DECL is a partial specialization. */
30036 {
30039 }
30042 }
30044 /* Add a new specialization described by SPEC. DECL is the
30045 maybe-template decl and FLAGS is as returned from
30046 get_mergeable_specialization_flags. */
30048 void
30051 {
30054 {
30063 {
30066 }
30067 }
30070 {
30073 /* We don't distinguish different constrained partial type
30074 specializations, so there could be duplicates. Everything else
30075 must be new. */
30077 {
30083 }
30084 }
30091 {
30092 /* A partial specialization. */
30097 }
30098 }
30100 /* Set up the hash tables for template instantiations. */
30102 void
30104 {
30110 }
30112 /* Print stats about the template hash tables for -fstats. */
30114 void
30116 {
30125 }
30127 #if CHECKING_P
30131 /* Verify that build_non_dependent_expr () works, for various expressions,
30132 and that location wrappers don't affect the results. */
30134 static void
30136 {
30139 /* Verify constants, without and with location wrappers. */
30156 }
30158 /* Verify that type_dependent_expression_p () works correctly, even
30159 in the presence of location wrapper nodes. */
30161 static void
30163 {
30168 /* If no templates are involved, nothing is type-dependent. */
30174 /* Within a template, an unresolved name is always type-dependent. */
30177 /* Ensure it copes with NULL_TREE and errors. */
30181 /* A USING_DECL in a template should be type-dependent, even if wrapped
30182 with a location wrapper (PR c++/83799). */
30191 }
30193 /* Run all of the selftests within this file. */
30195 void
30197 {
30200 }