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1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2020 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". */
47 /* The type of functions taking a tree, and some additional data, and
48 returning an int. */
51 /* The PENDING_TEMPLATES is a list of templates whose instantiations
52 have been deferred, either because their definitions were not yet
53 available, or because we were putting off doing the work. */
55 {
58 };
73 /* Live only within one (recursive) call to tsubst_expr. We use
74 this to pass the statement expression node from the STMT_EXPR
75 to the EXPR_STMT that is its result. */
78 // -------------------------------------------------------------------------- //
79 // Local Specialization Stack
80 //
81 // Implementation of the RAII helper for creating new local
82 // specializations.
85 {
87 ;
90 else
92 }
95 {
97 {
100 }
101 }
103 /* True if we've recursed into fn_type_unification too many times. */
107 {
108 tree tmpl;
109 tree args;
110 tree spec;
111 };
114 {
117 };
119 /* The general template is not in these tables. */
124 /* Contains canonical template parameter types. The vector is indexed by
125 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
126 TREE_LIST, whose TREE_VALUEs contain the canonical template
127 parameters of various types and levels. */
130 #define UNIFY_ALLOW_NONE 0
131 #define UNIFY_ALLOW_MORE_CV_QUAL 1
132 #define UNIFY_ALLOW_LESS_CV_QUAL 2
133 #define UNIFY_ALLOW_DERIVED 4
134 #define UNIFY_ALLOW_INTEGER 8
135 #define UNIFY_ALLOW_OUTER_LEVEL 16
136 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
137 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
140 tbr_incomplete_type,
141 tbr_ambiguous_baseclass,
142 tbr_success
143 };
165 tree);
232 /* Make the current scope suitable for access checking when we are
233 processing T. T can be FUNCTION_DECL for instantiated function
234 template, VAR_DECL for static member variable, or TYPE_DECL for
235 alias template (needed by instantiate_decl). */
237 void
239 {
247 else
251 {
254 }
255 }
257 /* Restore the scope set up by push_access_scope. T is the node we
258 are processing. */
260 void
262 {
268 else
270 }
272 /* Do any processing required when DECL (a member template
273 declaration) is finished. Returns the TEMPLATE_DECL corresponding
274 to DECL, unless it is a specialization, in which case the DECL
275 itself is returned. */
277 tree
279 {
286 {
287 tree type;
295 {
299 }
301 }
306 {
308 {
311 }
312 else
314 }
315 else
320 }
322 /* Create a template info node. */
324 tree
326 {
331 }
333 /* Return the template info node corresponding to T, whatever T is. */
335 tree
337 {
359 }
361 /* Returns the template nesting level of the indicated class TYPE.
363 For example, in:
364 template <class T>
365 struct A
366 {
367 template <class U>
368 struct B {};
369 };
371 A<T>::B<U> has depth two, while A<T> has depth one.
372 Both A<T>::B<int> and A<int>::B<U> have depth one, if
373 they are instantiations, not specializations.
375 This function is guaranteed to return 0 if passed NULL_TREE so
376 that, for example, `template_class_depth (current_class_type)' is
377 always safe. */
379 int
381 {
385 {
393 {
396 else
398 }
401 else
403 }
406 }
408 /* Return TRUE if NODE instantiates a template that has arguments of
409 its own, be it directly a primary template or indirectly through a
410 partial specializations. */
411 static bool
413 {
425 /* So now we know we have a specialization, but it could be a full
426 or a partial specialization. To tell which, compare the depth of
427 its template arguments with those of its context. */
436 }
438 /* Subroutine of maybe_begin_member_template_processing.
439 Returns true if processing DECL needs us to push template parms. */
441 static bool
443 {
449 }
451 /* Subroutine of maybe_begin_member_template_processing.
452 Push the template parms in PARMS, starting from LEVELS steps into the
453 chain, and ending at the beginning, since template parms are listed
454 innermost first. */
456 static void
458 {
466 current_template_parms
472 NULL);
474 {
483 {
490 /* Push the CONST_DECL. */
496 }
497 }
498 }
500 /* Restore the template parameter context for a member template, a
501 friend template defined in a class definition, or a non-template
502 member of template class. */
504 void
506 {
507 tree parms;
512 {
515 /* Disregard full specializations (c++/60999). */
518 }
521 {
526 {
529 }
532 }
534 /* Remember how many levels of template parameters we pushed so that
535 we can pop them later. */
537 }
539 /* Undo the effects of maybe_begin_member_template_processing. */
541 void
543 {
552 {
556 }
557 }
559 /* Return a new template argument vector which contains all of ARGS,
560 but has as its innermost set of arguments the EXTRA_ARGS. */
562 static tree
564 {
565 tree new_args;
583 }
585 /* Like add_to_template_args, but only the outermost ARGS are added to
586 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
587 (EXTRA_ARGS) levels are added. This function is used to combine
588 the template arguments from a partial instantiation with the
589 template arguments used to attain the full instantiation from the
590 partial instantiation.
592 If ARGS is a TEMPLATE_DECL, use its parameters as args. */
594 tree
596 {
597 tree new_args;
602 {
605 }
607 /* If there are more levels of EXTRA_ARGS than there are ARGS,
608 something very fishy is going on. */
611 /* If *all* the new arguments will be the EXTRA_ARGS, just return
612 them. */
616 /* For the moment, we make ARGS look like it contains fewer levels. */
621 /* Now, we restore ARGS to its full dimensions. */
625 }
627 /* Return the N levels of innermost template arguments from the ARGS. */
629 tree
631 {
632 tree new_args;
638 /* If N is 1, just return the innermost set of template arguments. */
642 /* If we're not removing anything, just return the arguments we were
643 given. */
649 /* Make a new set of arguments, not containing the outer arguments. */
656 }
658 /* The inverse of get_innermost_template_args: Return all but the innermost
659 EXTRA_LEVELS levels of template arguments from the ARGS. */
661 static tree
663 {
664 tree new_args;
670 /* If N is 1, just return the outermost set of template arguments. */
674 /* If we're not removing anything, just return the arguments we were
675 given. */
680 /* Make a new set of arguments, not containing the inner arguments. */
687 }
689 /* We've got a template header coming up; push to a new level for storing
690 the parms. */
692 void
694 {
695 /* We use a non-tag-transparent scope here, which causes pushtag to
696 put tags in this scope, rather than in the enclosing class or
697 namespace scope. This is the right thing, since we want
698 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
699 global template class, push_template_decl handles putting the
700 TEMPLATE_DECL into top-level scope. For a nested template class,
701 e.g.:
703 template <class T> struct S1 {
704 template <class T> struct S2 {};
705 };
707 pushtag contains special code to insert the TEMPLATE_DECL for S2
708 at the right scope. */
714 /* Add a dummy parameter level while we process the parameter list. */
715 current_template_parms
718 current_template_parms);
719 }
721 /* This routine is called when a specialization is declared. If it is
722 invalid to declare a specialization here, an error is reported and
723 false is returned, otherwise this routine will return true. */
725 static bool
727 {
730 /* [temp.expl.spec]
732 An explicit specialization shall be declared in the namespace of
733 which the template is a member, or, for member templates, in the
734 namespace of which the enclosing class or enclosing class
735 template is a member. An explicit specialization of a member
736 function, member class or static data member of a class template
737 shall be declared in the namespace of which the class template
738 is a member. */
740 {
743 }
745 /* [temp.expl.spec]
747 In an explicit specialization declaration for a member of a class
748 template or a member template that appears in namespace scope,
749 the member template and some of its enclosing class templates may
750 remain unspecialized, except that the declaration shall not
751 explicitly specialize a class member template if its enclosing
752 class templates are not explicitly specialized as well. */
754 {
757 }
760 }
762 /* We've just seen template <>. */
764 bool
766 {
770 }
772 /* Called at then end of processing a declaration preceded by
773 template<>. */
775 void
777 {
780 }
782 /* Any template <>'s that we have seen thus far are not referring to a
783 function specialization. */
785 void
787 {
790 }
792 /* We've just seen a template header. If SPECIALIZATION is nonzero,
793 it was of the form template <>. */
795 static void
797 {
799 template_header_count++;
800 }
802 /* We're beginning an explicit instantiation. */
804 void
806 {
809 }
812 void
814 {
817 }
819 /* An explicit specialization or partial specialization of TMPL is being
820 declared. Check that the namespace in which the specialization is
821 occurring is permissible. Returns false iff it is invalid to
822 specialize TMPL in the current namespace. */
824 static bool
826 {
829 /* [tmpl.expl.spec]
831 An explicit specialization shall be declared in a namespace enclosing the
832 specialized template. An explicit specialization whose declarator-id is
833 not qualified shall be declared in the nearest enclosing namespace of the
834 template, or, if the namespace is inline (7.3.1), any namespace from its
835 enclosing namespace set. */
838 {
841 }
844 /* Same or enclosing namespace. */
846 else
847 {
848 auto_diagnostic_group d;
854 }
855 }
857 /* SPEC is an explicit instantiation. Check that it is valid to
858 perform this explicit instantiation in the current namespace. */
860 static void
862 {
863 tree ns;
865 /* DR 275: An explicit instantiation shall appear in an enclosing
866 namespace of its template. */
872 }
874 /* Returns the type of a template specialization only if that
875 specialization needs to be defined. Otherwise (e.g., if the type has
876 already been defined), the function returns NULL_TREE. */
878 static tree
880 {
881 /* An implicit instantiation of an incomplete type implies
882 the definition of a new class template.
884 template<typename T>
885 struct S;
887 template<typename T>
888 struct S<T*>;
890 Here, S<T*> is an implicit instantiation of S whose type
891 is incomplete. */
895 /* It can also be the case that TYPE is a completed specialization.
896 Continuing the previous example, suppose we also declare:
898 template<typename T>
899 requires Integral<T>
900 struct S<T*>;
902 Here, S<T*> refers to the specialization S<T*> defined
903 above. However, we need to differentiate definitions because
904 we intend to define a new partial specialization. In this case,
905 we rely on the fact that the constraints are different for
906 this declaration than that above.
908 Note that we also get here for injected class names and
909 late-parsed template definitions. We must ensure that we
910 do not create new type declarations for those cases. */
912 {
916 /* If there are no template parameters, this cannot be a new
917 partial template specialization? */
921 /* The injected-class-name is not a new partial specialization. */
925 /* If the constraints are not the same as those of the primary
926 then, we can probably create a new specialization. */
930 {
934 }
936 /* Also, if there's a pre-existing specialization with matching
937 constraints, then this also isn't new. */
940 {
948 }
950 /* Create a new type node (and corresponding type decl)
951 for the newly declared specialization. */
956 /* We only need a separate type node for storing the definition of this
957 partial specialization; uses of S<T*> are unconstrained, so all are
958 equivalent. So keep TYPE_CANONICAL the same. */
961 /* Build the corresponding type decl. */
969 }
972 }
974 /* The TYPE is being declared. If it is a template type, that means it
975 is a partial specialization. Do appropriate error-checking. */
977 tree
979 {
980 tree context;
985 /* A lambda that appears in specialization context is not itself a
986 specialization. */
991 {
995 }
1000 {
1006 else
1009 }
1011 {
1012 /* This is for ordinary explicit specialization and partial
1013 specialization of a template class such as:
1015 template <> class C<int>;
1017 or:
1019 template <class T> class C<T*>;
1021 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
1024 {
1031 {
1036 }
1037 }
1043 /* Trying to define a specialization either without a template<> header
1044 or in an inappropriate place. We've already given an error, so just
1045 bail now so we don't actually define the specialization. */
1047 }
1053 {
1054 /* This is for an explicit specialization of member class
1055 template according to [temp.expl.spec/18]:
1057 template <> template <class U> class C<int>::D;
1059 The context `C<int>' must be an implicit instantiation.
1060 Otherwise this is just a member class template declared
1061 earlier like:
1063 template <> class C<int> { template <class U> class D; };
1064 template <> template <class U> class C<int>::D;
1066 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1067 while in the second case, `C<int>::D' is a primary template
1068 and `C<T>::D' may not exist. */
1072 {
1073 tree t;
1078 {
1081 type))
1084 }
1086 /* Check for invalid specialization after instantiation:
1088 template <> template <> class C<int>::D<int>;
1089 template <> template <class U> class C<int>::D; */
1093 {
1097 {
1098 /* We already have a full specialization of this partial
1099 instantiation, or a full specialization has been
1100 looked up but not instantiated. Reassign it to the
1101 new member specialization template. */
1102 spec_entry elt;
1115 spec_entry **slot
1120 }
1121 else
1122 /* But if we've had an implicit instantiation, that's a
1123 problem ([temp.expl.spec]/6). */
1126 }
1128 /* Mark TYPE as a specialization. And as a result, we only
1129 have one level of template argument for the innermost
1130 class template. */
1135 }
1136 }
1138 {
1139 /* Someday C++0x may allow for enum template specialization. */
1144 else
1145 {
1148 }
1149 }
1152 }
1154 /* Returns nonzero if we can optimize the retrieval of specializations
1155 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1156 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1160 {
1163 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1164 parameter. */
1166 /* The optimized lookup depends on the fact that the
1167 template arguments for the member function template apply
1168 purely to the containing class, which is not true if the
1169 containing class is an explicit or partial
1170 specialization. */
1174 /* It is possible to have a template that is not a member
1175 template and is not a member of a template class:
1177 template <typename T>
1178 struct S { friend A::f(); };
1180 Here, the friend function is a template, but the context does
1181 not have template information. The optimized lookup relies
1182 on having ARGS be the template arguments for both the class
1183 and the function template. */
1185 }
1187 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1188 gone through coerce_template_parms by now. */
1190 static void
1192 {
1194 {
1203 /* Allow typedefs on the type of a non-type argument, since a
1205 else
1207 }
1208 }
1210 static void
1212 {
1217 }
1219 /* Retrieve the specialization (in the sense of [temp.spec] - a
1220 specialization is either an instantiation or an explicit
1221 specialization) of TMPL for the given template ARGS. If there is
1222 no such specialization, return NULL_TREE. The ARGS are a vector of
1223 arguments, or a vector of vectors of arguments, in the case of
1224 templates with more than one level of parameters.
1226 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1227 then we search for a partial specialization matching ARGS. This
1228 parameter is ignored if TMPL is not a class template.
1230 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1231 result is a NONTYPE_ARGUMENT_PACK. */
1233 static tree
1235 {
1245 /* There should be as many levels of arguments as there are
1246 levels of parameters. */
1255 /* Lambda functions in templates aren't instantiated normally, but through
1256 tsubst_lambda_expr. */
1261 {
1262 /* The template arguments actually apply to the containing
1263 class. Find the class specialization with those
1264 arguments. */
1266 tree class_specialization
1271 /* Find the instance of TMPL. */
1274 {
1278 /* using-declarations can bring in a different
1279 instantiation of tmpl as a member of a different
1280 instantiation of tmpl's class. We don't want those
1281 here. */
1284 }
1286 }
1287 else
1288 {
1290 spec_entry elt;
1299 else
1307 }
1310 }
1312 /* Like retrieve_specialization, but for local declarations. */
1314 tree
1316 {
1322 }
1324 /* Returns nonzero iff DECL is a specialization of TMPL. */
1326 int
1328 {
1329 tree t;
1332 {
1338 }
1339 else
1340 {
1349 }
1352 }
1354 /* Returns nonzero iff DECL is a specialization of friend declaration
1355 FRIEND_DECL according to [temp.friend]. */
1357 bool
1359 {
1366 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1367 of a template class, we want to check if DECL is a specialization
1368 if this. */
1372 {
1373 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1376 }
1381 /* There is nothing to do if this is not a template friend. */
1388 /* [temp.friend/6]
1389 A member of a class template may be declared to be a friend of a
1390 non-template class. In this case, the corresponding member of
1391 every specialization of the class template is a friend of the
1392 class granting friendship.
1394 For example, given a template friend declaration
1396 template <class T> friend void A<T>::f();
1398 the member function below is considered a friend
1400 template <> struct A<int> {
1401 void f();
1402 };
1404 For this type of template friend, TEMPLATE_DEPTH below will be
1405 nonzero. To determine if DECL is a friend of FRIEND, we first
1406 check if the enclosing class is a specialization of another. */
1413 {
1414 /* Next, we check the members themselves. In order to handle
1415 a few tricky cases, such as when FRIEND_DECL's are
1417 template <class T> friend void A<T>::g(T t);
1418 template <class T> template <T t> friend void A<T>::h();
1420 and DECL's are
1422 void A<int>::g(int);
1423 template <int> void A<int>::h();
1425 we need to figure out ARGS, the template arguments from
1426 the context of DECL. This is required for template substitution
1427 of `T' in the function parameter of `g' and template parameter
1428 of `h' in the above examples. Here ARGS corresponds to `int'. */
1435 {
1437 {
1440 else
1442 current_depth++;
1443 }
1445 }
1448 {
1450 tree friend_type;
1451 tree decl_type;
1452 tree friend_args_type;
1453 tree decl_args_type;
1455 /* Make sure that both DECL and FRIEND_DECL are templates or
1456 non-templates. */
1462 {
1463 /* If both are templates, check template parameter list. */
1464 tree friend_parms
1469 friend_parms))
1473 }
1474 else
1482 /* Check if return types match. */
1486 /* Check if function parameter types match, ignoring the
1487 `this' parameter. */
1496 }
1497 else
1498 {
1499 /* DECL is a TYPE_DECL */
1503 /* Make sure that both DECL and FRIEND_DECL are templates or
1504 non-templates. */
1505 is_template
1512 {
1513 tree friend_parms;
1514 /* If both are templates, check the name of the two
1515 TEMPLATE_DECL's first because is_friend didn't. */
1520 /* Now check template parameter list. */
1521 friend_parms
1524 return comp_template_parms
1526 friend_parms);
1527 }
1528 else
1531 }
1532 }
1534 }
1536 /* Register the specialization SPEC as a specialization of TMPL with
1537 the indicated ARGS. IS_FRIEND indicates whether the specialization
1538 is actually just a friend declaration. ATTRLIST is the list of
1539 attributes that the specialization is declared with or NULL when
1540 it isn't. Returns SPEC, or an equivalent prior declaration, if
1541 available.
1543 We also store instantiations of field packs in the hash table, even
1544 though they are not themselves templates, to make lookup easier. */
1546 static tree
1548 hashval_t hash)
1549 {
1550 tree fn;
1552 spec_entry elt;
1560 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1561 register it; we want the corresponding TEMPLATE_DECL instead.
1562 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1563 the more obvious `uses_template_parms (spec)' to avoid problems
1564 with default function arguments. In particular, given
1565 something like this:
1567 template <class T> void f(T t1, T t = T())
1569 the default argument expression is not substituted for in an
1570 instantiation unless and until it is actually needed. */
1574 /* We don't put these specializations in the hash table, but we might
1575 want to give an error about a mismatch. */
1577 else
1578 {
1589 else
1591 }
1593 /* We can sometimes try to re-register a specialization that we've
1594 already got. In particular, regenerate_decl_from_template calls
1595 duplicate_decls which will update the specialization list. But,
1596 we'll still get called again here anyhow. It's more convenient
1597 to simply allow this than to try to prevent it. */
1601 {
1603 {
1606 {
1608 fn);
1610 }
1611 else
1612 {
1613 tree clone;
1614 /* This situation should occur only if the first
1615 specialization is an implicit instantiation, the
1616 second is an explicit specialization, and the
1617 implicit instantiation has not yet been used. That
1618 situation can occur if we have implicitly
1619 instantiated a member function and then specialized
1620 it later.
1622 We can also wind up here if a friend declaration that
1623 looked like an instantiation turns out to be a
1624 specialization:
1626 template <class T> void foo(T);
1627 class S { friend void foo<>(int) };
1628 template <> void foo(int);
1630 We transform the existing DECL in place so that any
1631 pointers to it become pointers to the updated
1632 declaration.
1634 If there was a definition for the template, but not
1635 for the specialization, we want this to look as if
1636 there were no definition, and vice versa. */
1639 /* The call to duplicate_decls will have applied
1640 [temp.expl.spec]:
1642 An explicit specialization of a function template
1643 is inline only if it is explicitly declared to be,
1644 and independently of whether its function template
1645 is.
1647 to the primary function; now copy the inline bits to
1648 the various clones. */
1650 {
1657 }
1661 }
1662 }
1664 {
1667 /* We've already complained in duplicate_decls. */
1671 /* Dup decl failed, but this is a new definition. Set the
1672 line number so any errors match this new
1673 definition. */
1677 }
1678 }
1682 /* A specialization must be declared in the same namespace as the
1683 template it is specializing. */
1689 {
1698 /* If TMPL is a forward declaration of a template function, keep a list
1699 of all specializations in case we need to reassign them to a friend
1700 template later in tsubst_friend_function.
1702 Also keep a list of all variable template instantiations so that
1703 process_partial_specialization can check whether a later partial
1704 specialization would have used it. */
1707 }
1710 }
1712 /* Returns true iff two spec_entry nodes are equivalent. */
1716 bool
1718 {
1725 /* tmpl could be a FIELD_DECL for a capture pack. */
1729 {
1730 /* Partial specializations of a variable template can be distinguished by
1731 constraints. */
1735 }
1739 }
1741 /* Returns a hash for a template TMPL and template arguments ARGS. */
1743 static hashval_t
1745 {
1748 }
1750 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1751 ignoring SPEC. */
1753 hashval_t
1755 {
1757 }
1759 /* Recursively calculate a hash value for a template argument ARG, for use
1760 in the hash tables of template specializations. We must be
1761 careful to (at least) skip the same entities template_args_equal
1762 does. */
1764 hashval_t
1766 {
1771 /* Strip nop-like things, but not the same as STRIP_NOPS. */
1782 {
1817 {
1822 {
1825 }
1827 }
1831 {
1834 }
1845 val = iterative_hash_template_arg
1857 val);
1859 val);
1868 /* [temp.over.link] Two lambda-expressions are never considered
1869 equivalent.
1871 So just hash the closure type. */
1882 /* Now hash operands as usual. */
1886 {
1889 {
1893 }
1895 call_expr_arg_iterator ai;
1900 }
1904 }
1908 {
1911 {
1912 // We want an alias specialization that survived strip_typedefs
1913 // to hash differently from its TYPE_CANONICAL, to avoid hash
1914 // collisions that compare as different in template_args_equal.
1915 // These could be dependent specializations that strip_typedefs
1916 // left alone, or untouched specializations because
1917 // coerce_template_parms returns the unconverted template
1918 // arguments if it sees incomplete argument packs.
1921 }
1924 {
1926 {
1929 /* Do not recurse with TPI directly, as that is unbounded
1930 recursion. */
1933 }
1944 }
1957 }
1961 }
1963 /* Unregister the specialization SPEC as a specialization of TMPL.
1964 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1965 if the SPEC was listed as a specialization of TMPL.
1967 Note that SPEC has been ggc_freed, so we can't look inside it. */
1969 bool
1971 {
1973 spec_entry elt;
1981 {
1986 }
1989 }
1991 /* Like register_specialization, but for local declarations. We are
1992 registering SPEC, an instantiation of TMPL. */
1994 void
1996 {
1999 }
2001 /* TYPE is a class type. Returns true if TYPE is an explicitly
2002 specialized class. */
2004 bool
2006 {
2010 }
2012 /* Print the list of functions at FNS, going through all the overloads
2013 for each element of the list. Alternatively, FNS cannot be a
2014 TREE_LIST, in which case it will be printed together with all the
2015 overloads.
2017 MORE and *STR should respectively be FALSE and NULL when the function
2018 is called from the outside. They are used internally on recursive
2019 calls. print_candidates manages the two parameters and leaves NULL
2020 in *STR when it ends. */
2022 static void
2024 {
2028 else
2030 {
2036 {
2039 else
2042 }
2044 }
2045 }
2047 /* Print the list of candidate FNS in an error message. FNS can also
2048 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
2050 void
2052 {
2056 }
2058 /* Get a (possibly) constrained template declaration for the
2059 purpose of ordering candidates. */
2060 static tree
2062 {
2068 }
2070 /* Among candidates having the same signature, return the
2071 most constrained or NULL_TREE if there is no best candidate.
2072 If the signatures of candidates vary (e.g., template
2073 specialization vs. member function), then there can be no
2074 most constrained.
2076 Note that we don't compare constraints on the functions
2077 themselves, but rather those of their templates. */
2078 static tree
2080 {
2081 // Try to find the best candidate in a first pass.
2084 {
2091 }
2093 // Verify that the champ is better than previous candidates.
2098 }
2101 }
2104 /* Returns the template (one of the functions given by TEMPLATE_ID)
2105 which can be specialized to match the indicated DECL with the
2106 explicit template args given in TEMPLATE_ID. The DECL may be
2107 NULL_TREE if none is available. In that case, the functions in
2108 TEMPLATE_ID are non-members.
2110 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2111 specialization of a member template.
2113 The TEMPLATE_COUNT is the number of references to qualifying
2114 template classes that appeared in the name of the function. See
2115 check_explicit_specialization for a more accurate description.
2117 TSK indicates what kind of template declaration (if any) is being
2118 declared. TSK_TEMPLATE indicates that the declaration given by
2119 DECL, though a FUNCTION_DECL, has template parameters, and is
2120 therefore a template function.
2122 The template args (those explicitly specified and those deduced)
2123 are output in a newly created vector *TARGS_OUT.
2125 If it is impossible to determine the result, an error message is
2126 issued. The error_mark_node is returned to indicate failure. */
2128 static tree
2130 tree decl,
2134 tmpl_spec_kind tsk)
2135 {
2136 tree fns;
2137 tree targs;
2138 tree explicit_targs;
2141 /* A TREE_LIST of templates of which DECL may be a specialization.
2142 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2143 corresponding TREE_PURPOSE is the set of template arguments that,
2144 when used to instantiate the template, would produce a function
2145 with the signature of DECL. */
2155 /* We shouldn't be specializing a member template of an
2156 unspecialized class template; we already gave an error in
2157 check_specialization_scope, now avoid crashing. */
2161 {
2164 }
2172 /* Check for baselinks. */
2177 {
2181 }
2183 {
2186 }
2188 /* Count the number of template headers specified for this
2189 specialization. */
2199 {
2202 tf_warning_or_error,
2206 }
2208 {
2212 {
2213 tree decl_arg_types;
2214 tree fn_arg_types;
2215 tree insttype;
2217 /* In case of explicit specialization, we need to check if
2218 the number of template headers appearing in the specialization
2219 is correct. This is usually done in check_explicit_specialization,
2220 but the check done there cannot be exhaustive when specializing
2221 member functions. Consider the following code:
2223 template <> void A<int>::f(int);
2224 template <> template <> void A<int>::f(int);
2226 Assuming that A<int> is not itself an explicit specialization
2227 already, the first line specializes "f" which is a non-template
2228 member function, whilst the second line specializes "f" which
2229 is a template member function. So both lines are syntactically
2230 correct, and check_explicit_specialization does not reject
2231 them.
2233 Here, we can do better, as we are matching the specialization
2234 against the declarations. We count the number of template
2235 headers, and we check if they match TEMPLATE_COUNT + 1
2236 (TEMPLATE_COUNT is the number of qualifying template classes,
2237 plus there must be another header for the member template
2238 itself).
2240 Notice that if header_count is zero, this is not a
2241 specialization but rather a template instantiation, so there
2242 is no check we can perform here. */
2246 /* Check that the number of template arguments at the
2247 innermost level for DECL is the same as for FN. */
2255 /* DECL might be a specialization of FN. */
2259 /* For a non-static member function, we need to make sure
2260 that the const qualification is the same. Since
2261 get_bindings does not try to merge the "this" parameter,
2262 we must do the comparison explicitly. */
2264 {
2269 /* And the ref-qualification. */
2273 }
2275 /* Skip the "this" parameter and, for constructors of
2276 classes with virtual bases, the VTT parameter. A
2277 full specialization of a constructor will have a VTT
2278 parameter, but a template never will. */
2279 decl_arg_types
2281 fn_arg_types
2284 /* Function templates cannot be specializations; there are
2285 no partial specializations of functions. Therefore, if
2286 the type of DECL does not match FN, there is no
2287 match.
2289 Note that it should never be the case that we have both
2290 candidates added here, and for regular member functions
2291 below. */
2293 {
2295 current_template_parms))
2308 {
2314 }
2318 }
2320 /* See whether this function might be a specialization of this
2321 template. Suppress access control because we might be trying
2322 to make this specialization a friend, and we have already done
2323 access control for the declaration of the specialization. */
2329 /* We cannot deduce template arguments that when used to
2330 specialize TMPL will produce DECL. */
2334 /* We deduced something involving 'auto', which isn't a valid
2335 template argument. */
2338 /* Remove, from the set of candidates, all those functions
2339 whose constraints are not satisfied. */
2343 // Then, try to form the new function type.
2347 fn_arg_types
2352 /* Save this template, and the arguments deduced. */
2354 }
2356 /* FN is an ordinary member function, and we need a
2357 specialization of a member template. */
2358 ;
2360 /* We can get IDENTIFIER_NODEs here in certain erroneous
2361 cases. */
2362 ;
2364 /* This is just an ordinary non-member function. Nothing can
2365 be a specialization of that. */
2366 ;
2368 /* Cannot specialize functions that are created implicitly. */
2369 ;
2370 else
2371 {
2372 tree decl_arg_types;
2374 /* This is an ordinary member function. However, since
2375 we're here, we can assume its enclosing class is a
2376 template class. For example,
2378 template <typename T> struct S { void f(); };
2379 template <> void S<int>::f() {}
2381 Here, S<int>::f is a non-template, but S<int> is a
2382 template class. If FN has the same type as DECL, we
2383 might be in business. */
2386 /* Its enclosing class is an explicit specialization
2387 of a template class. This is not a candidate. */
2392 /* The return types differ. */
2395 /* Adjust the type of DECL in case FN is a static member. */
2402 decl_arg_types))
2410 // If the deduced arguments do not satisfy the constraints,
2411 // this is not a candidate.
2415 // Add the candidate.
2417 }
2418 }
2421 {
2422 /* We have:
2424 [temp.expl.spec]
2426 It is possible for a specialization with a given function
2427 signature to be instantiated from more than one function
2428 template. In such cases, explicit specification of the
2429 template arguments must be used to uniquely identify the
2430 function template specialization being specialized.
2432 Note that here, there's no suggestion that we're supposed to
2433 determine which of the candidate templates is most
2434 specialized. However, we, also have:
2436 [temp.func.order]
2438 Partial ordering of overloaded function template
2439 declarations is used in the following contexts to select
2440 the function template to which a function template
2441 specialization refers:
2443 -- when an explicit specialization refers to a function
2444 template.
2446 So, we do use the partial ordering rules, at least for now.
2447 This extension can only serve to make invalid programs valid,
2448 so it's safe. And, there is strong anecdotal evidence that
2449 the committee intended the partial ordering rules to apply;
2450 the EDG front end has that behavior, and John Spicer claims
2451 that the committee simply forgot to delete the wording in
2452 [temp.expl.spec]. */
2455 {
2458 }
2459 }
2461 // Concepts allows multiple declarations of member functions
2462 // with the same signature. Like above, we need to rely on
2463 // on the partial ordering of those candidates to determine which
2464 // is the best.
2466 {
2468 {
2471 }
2472 }
2475 {
2480 "saw %d %<template<>%>, need %d for "
2483 else
2486 }
2490 {
2496 }
2498 /* We have one, and exactly one, match. */
2500 {
2504 /* Propagate the candidate's constraints to the declaration. */
2508 /* DECL is a re-declaration or partial instantiation of a template
2509 function. */
2512 /* It was a specialization of an ordinary member function in a
2513 template class. */
2515 }
2517 /* It was a specialization of a template. */
2520 {
2525 }
2526 else
2529 }
2531 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2532 but with the default argument values filled in from those in the
2533 TMPL_TYPES. */
2535 static tree
2537 tree tmpl_types)
2538 {
2539 tree new_spec_types;
2547 /* Substitute into the rest of the list. */
2548 new_spec_types =
2552 /* Add the default argument for this parameter. */
2555 new_spec_types);
2556 }
2558 /* DECL is an explicit specialization. Replicate default arguments
2559 from the template it specializes. (That way, code like:
2561 template <class T> void f(T = 3);
2562 template <> void f(double);
2563 void g () { f (); }
2565 works, as required.) An alternative approach would be to look up
2566 the correct default arguments at the call-site, but this approach
2567 is consistent with how implicit instantiations are handled. */
2569 static void
2571 {
2572 tree tmpl;
2573 tree spec_types;
2574 tree tmpl_types;
2575 tree new_spec_types;
2576 tree old_type;
2577 tree new_type;
2578 tree t;
2583 /* See if there's anything we need to do. */
2596 {
2597 /* Remove the this pointer, but remember the object's type for
2598 CV quals. */
2604 {
2605 /* DECL may contain more parameters than TMPL due to the extra
2606 in-charge parameter in constructors and destructors. */
2609 }
2611 {
2614 }
2615 }
2617 /* Compute the merged default arguments. */
2618 new_spec_types =
2621 /* Compute the new FUNCTION_TYPE. */
2623 {
2627 new_spec_types);
2630 /* Put the in-charge parameter back. */
2633 new_spec_types);
2637 new_spec_types);
2638 }
2639 else
2641 new_spec_types);
2647 }
2649 /* Return the number of template headers we expect to see for a definition
2650 or specialization of CTYPE or one of its non-template members. */
2652 int
2654 {
2658 {
2659 /* You're supposed to have one `template <...>' for every
2660 template class, but you don't need one for a full
2661 specialization. For example:
2663 template <class T> struct S{};
2664 template <> struct S<int> { void f(); };
2665 void S<int>::f () {}
2667 is correct; there shouldn't be a `template <>' for the
2668 definition of `S<int>::f'. */
2670 /* If CTYPE does not have template information of any
2671 kind, then it is not a template, nor is it nested
2672 within a template. */
2680 }
2683 }
2685 /* Do a simple sanity check on the template headers that precede the
2686 variable declaration DECL. */
2688 void
2690 {
2695 {
2698 "variable templates only available with "
2701 // Namespace-scope variable templates should have a template header.
2703 }
2705 {
2706 auto_diagnostic_group d;
2708 "too many template headers for %qD "
2714 "members of an explicitly specialized class are defined "
2716 }
2717 }
2719 /* An explicit specialization whose declarator-id or class-head-name is not
2720 qualified shall be declared in the nearest enclosing namespace of the
2721 template, or, if the namespace is inline (7.3.1), any namespace from its
2722 enclosing namespace set.
2724 If the name declared in the explicit instantiation is an unqualified name,
2725 the explicit instantiation shall appear in the namespace where its template
2726 is declared or, if that namespace is inline (7.3.1), any namespace from its
2727 enclosing namespace set. */
2729 void
2731 {
2736 {
2742 /* This was allowed in C++98, so only pedwarn. */
2744 "outside its namespace must use a nested-name-"
2746 }
2747 }
2749 /* Warn for a template specialization SPEC that is missing some of a set
2750 of function or type attributes that the template TEMPL is declared with.
2751 ATTRLIST is a list of additional attributes that SPEC should be taken
2752 to ultimately be declared with. */
2754 static void
2756 {
2760 /* Avoid warning if the difference between the primary and
2761 the specialization is not in one of the attributes below. */
2765 };
2767 /* Put together a list of the black listed attributes that the primary
2768 template is declared with that the specialization is not, in case
2769 it's not apparent from the most recent declaration of the primary. */
2770 pretty_printer str;
2777 auto_diagnostic_group d;
2780 spec))
2786 }
2788 /* Check to see if the function just declared, as indicated in
2789 DECLARATOR, and in DECL, is a specialization of a function
2790 template. We may also discover that the declaration is an explicit
2791 instantiation at this point.
2793 Returns DECL, or an equivalent declaration that should be used
2794 instead if all goes well. Issues an error message if something is
2795 amiss. Returns error_mark_node if the error is not easily
2796 recoverable.
2798 FLAGS is a bitmask consisting of the following flags:
2800 2: The function has a definition.
2801 4: The function is a friend.
2803 The TEMPLATE_COUNT is the number of references to qualifying
2804 template classes that appeared in the name of the function. For
2805 example, in
2807 template <class T> struct S { void f(); };
2808 void S<int>::f();
2810 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2811 classes are not counted in the TEMPLATE_COUNT, so that in
2813 template <class T> struct S {};
2814 template <> struct S<int> { void f(); }
2815 template <> void S<int>::f();
2817 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2818 invalid; there should be no template <>.)
2820 If the function is a specialization, it is marked as such via
2821 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2822 is set up correctly, and it is added to the list of specializations
2823 for that template. */
2825 tree
2827 tree decl,
2830 tree attrlist)
2831 {
2840 tmpl_spec_kind tsk;
2843 {
2846 else
2848 }
2849 else
2853 {
2856 {
2859 }
2861 {
2863 /* This could be something like:
2865 template <class T> void f(T);
2866 class S { friend void f<>(int); } */
2868 else
2869 {
2870 /* This case handles bogus declarations like template <>
2871 template <class T> void f<int>(); */
2875 declarator);
2877 }
2878 }
2882 /* The error has already been reported in
2883 check_specialization_scope. */
2889 /* Fall through. */
2902 decl);
2905 else
2909 /* Fall through. */
2915 /* In cases like template<> constexpr bool v = true;
2916 We'll give an error in check_template_variable. */
2922 else
2928 {
2929 /* This case handles bogus declarations like template <>
2930 template <class T> void f<int>(); */
2935 declarator);
2937 {
2938 /* Partial specialization of variable template. */
2942 }
2945 "non-type partial specialization %qE "
2947 else
2949 "non-class, non-variable partial specialization %qE "
2952 ok:;
2953 }
2956 /* This is a specialization of a member template, without
2957 specialization the containing class. Something like:
2959 template <class T> struct S {
2960 template <class U> void f (U);
2961 };
2962 template <> template <class U> void S<int>::f(U) {}
2964 That's a specialization -- but of the entire template. */
2970 }
2973 /* This doesn't apply to variable templates. */
2975 {
2979 {
2983 }
2984 }
2987 {
2993 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2995 {
2996 tree fns;
3001 else
3002 {
3003 /* If there is no class context, the explicit instantiation
3004 must be at namespace scope. */
3007 /* Find the namespace binding, using the declaration
3008 context. */
3012 {
3013 /* If lookup fails, look for a friend declaration so we can
3014 give a better diagnostic. */
3015 fns = (lookup_qualified_name
3020 }
3023 {
3026 }
3027 }
3030 }
3036 {
3038 /* A specialization in class scope. This is invalid,
3039 but the error will already have been flagged by
3040 check_specialization_scope. */
3042 else
3043 {
3044 /* It's not valid to write an explicit instantiation in
3045 class scope, e.g.:
3047 class C { template void f(); }
3049 This case is caught by the parser. However, on
3050 something like:
3052 template class C { void f(); };
3054 (which is invalid) we can get here. The error will be
3055 issued later. */
3056 ;
3057 }
3060 }
3063 {
3064 // We'll match variable templates in start_decl.
3068 /* Find the list of functions in ctype that have the same
3069 name as the declared function. */
3073 {
3077 {
3078 /* From [temp.expl.spec]:
3080 If such an explicit specialization for the member
3081 of a class template names an implicitly-declared
3082 special member function (clause _special_), the
3083 program is ill-formed.
3085 Similar language is found in [temp.explicit]. */
3088 }
3091 }
3093 /* For a type-conversion operator, We might be looking for
3094 `operator int' which will be a specialization of
3095 `operator T'. Grab all the conversion operators, and
3096 then select from them. */
3101 {
3104 }
3105 else
3107 }
3109 /* Figure out what exactly is being specialized at this point.
3110 Note that for an explicit instantiation, even one for a
3111 member function, we cannot tell a priori whether the
3112 instantiation is for a member template, or just a member
3113 function of a template class. Even if a member template is
3114 being instantiated, the member template arguments may be
3115 elided if they can be deduced from the rest of the
3116 declaration. */
3119 member_specialization,
3120 template_count,
3121 tsk);
3124 /* We couldn't figure out what this declaration was
3125 specializing. */
3127 else
3128 {
3130 {
3131 auto_diagnostic_group d;
3133 "friend declaration %qD is not visible to "
3137 }
3146 {
3147 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3148 is done by do_decl_instantiation later. */
3154 {
3155 /* If TMPL is not the most general template (for
3156 example, if TMPL is a friend template that is
3157 injected into namespace scope), then there will
3158 be too many levels of TARGS. Remove some of them
3159 here. */
3161 tree new_targs;
3168 }
3171 }
3173 /* If we thought that the DECL was a member function, but it
3174 turns out to be specializing a static member function,
3175 make DECL a static member function as well. */
3181 /* If this is a specialization of a member template of a
3182 template class, we want to return the TEMPLATE_DECL, not
3183 the specialization of it. */
3185 {
3190 {
3191 tree parm;
3195 /* We want to use the argument list specified in the
3196 definition, not in the original declaration. */
3201 }
3204 }
3206 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3212 /* Inherit default function arguments from the template
3213 DECL is specializing. */
3217 /* This specialization has the same protection as the
3218 template it specializes. */
3222 /* 7.1.1-1 [dcl.stc]
3224 A storage-class-specifier shall not be specified in an
3225 explicit specialization...
3227 The parser rejects these, so unless action is taken here,
3228 explicit function specializations will always appear with
3229 global linkage.
3231 The action recommended by the C++ CWG in response to C++
3232 defect report 605 is to make the storage class and linkage
3233 of the explicit specialization match the templated function:
3235 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3236 */
3238 {
3242 /* A concept cannot be specialized. */
3244 {
3246 gen_tmpl);
3248 }
3250 /* This specialization has the same linkage and visibility as
3251 the function template it specializes. */
3254 {
3257 }
3260 {
3263 }
3264 }
3266 /* If DECL is a friend declaration, declared using an
3267 unqualified name, the namespace associated with DECL may
3268 have been set incorrectly. For example, in:
3270 template <typename T> void f(T);
3271 namespace N {
3272 struct S { friend void f<int>(int); }
3273 }
3275 we will have set the DECL_CONTEXT for the friend
3276 declaration to N, rather than to the global namespace. */
3281 /* This is not really a declaration of a specialization.
3282 It's just the name of an instantiation. But, it's not
3283 a request for an instantiation, either. */
3286 /* A specialization is not necessarily COMDAT. */
3292 /* If this is a full specialization, register it so that we can find
3293 it again. Partial specializations will be registered in
3294 process_partial_specialization. */
3296 {
3301 }
3304 /* A 'structor should already have clones. */
3310 }
3311 }
3314 }
3316 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3317 parameters. These are represented in the same format used for
3318 DECL_TEMPLATE_PARMS. */
3320 int
3322 {
3323 const_tree p1;
3324 const_tree p2;
3332 {
3344 {
3348 /* If either of the template parameters are invalid, assume
3349 they match for the sake of error recovery. */
3362 }
3363 }
3366 /* One set of parameters has more parameters lists than the
3367 other. */
3371 }
3373 /* Returns true if two template parameters are declared with
3374 equivalent constraints. */
3376 static bool
3378 {
3386 }
3388 /* Returns true when two template parameters are equivalent. */
3390 static bool
3392 {
3396 /* If either of the template parameters are invalid, assume
3397 they match for the sake of error recovery. */
3401 /* ... they declare parameters of the same kind. */
3405 /* ... one parameter was introduced by a parameter declaration, then
3406 both are. This case arises as a result of eagerly rewriting declarations
3407 during parsing. */
3411 /* ... if either declares a pack, they both do. */
3416 {
3417 /* ... if they declare non-type parameters, the types are equivalent. */
3420 }
3422 {
3423 /* ... if they declare template template parameters, their template
3424 parameter lists are equivalent. */
3427 }
3429 /* ... if they are declared with a qualified-concept name, they both
3430 are, and those names are equivalent. */
3432 }
3434 /* Returns true if two template parameters lists are equivalent.
3435 Two template parameter lists are equivalent if they have the
3436 same length and their corresponding parameters are equivalent.
3438 PARMS1 and PARMS2 are TREE_LISTs containing TREE_VECs: the
3439 data structure returned by DECL_TEMPLATE_PARMS.
3441 This is generally the same implementation as comp_template_parms
3442 except that it also the concept names and arguments used to
3443 introduce parameters. */
3445 static bool
3447 {
3454 {
3462 {
3467 }
3471 }
3477 }
3479 /* Return true if the requires-clause of the template parameter lists are
3480 equivalent and false otherwise. */
3481 static bool
3483 {
3491 }
3493 /* Returns true if two template heads are equivalent. 17.6.6.1p6:
3494 Two template heads are equivalent if their template parameter
3495 lists are equivalent and their requires clauses are equivalent.
3497 In pre-C++20, this is equivalent to calling comp_template_parms
3498 for the template parameters of TMPL1 and TMPL2. */
3500 bool
3502 {
3506 /* Don't change the matching rules for pre-C++20. */
3510 /* ... have the same number of template parameters, and their
3511 corresponding parameters are equivalent. */
3515 /* ... if either has a requires-clause, they both do and their
3516 corresponding constraint-expressions are equivalent. */
3518 }
3520 /* Determine whether PARM is a parameter pack. */
3522 bool
3524 {
3525 /* Determine if we have a non-type template parameter pack. */
3532 /* If this is a list of template parameters, we could get a
3533 TYPE_DECL or a TEMPLATE_DECL. */
3537 /* Otherwise it must be a type template parameter. */
3541 }
3543 /* Determine if T is a function parameter pack. */
3545 bool
3547 {
3551 }
3553 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3554 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3556 tree
3558 {
3565 }
3567 /* Return true iff the function parameter PARAM_DECL was expanded
3568 from the function parameter pack PACK. */
3570 bool
3572 {
3577 /* The parameter pack and its pack arguments have the same
3578 DECL_PARM_INDEX. */
3580 }
3582 /* Determine whether ARGS describes a variadic template args list,
3583 i.e., one that is terminated by a template argument pack. */
3585 static bool
3587 {
3589 tree last_parm;
3603 }
3605 /* Generate a new name for the parameter pack name NAME (an
3606 IDENTIFIER_NODE) that incorporates its */
3608 static tree
3610 {
3611 /* Munge the name to include the parameter index. */
3612 #define NUMBUF_LEN 128
3626 }
3628 /* Return true if T is a primary function, class or alias template
3629 specialization, not including the template pattern. */
3631 bool
3633 {
3649 }
3651 /* Return true if PARM is a template template parameter. */
3653 bool
3655 {
3657 }
3659 /* Return true iff PARM is a DECL representing a type template
3660 parameter. */
3662 bool
3664 {
3669 }
3671 /* Return the template parameters of T if T is a
3672 primary template instantiation, NULL otherwise. */
3674 tree
3676 {
3681 parms = INNERMOST_TEMPLATE_PARMS
3685 }
3687 /* Return the template parameters of the LEVELth level from the full list
3688 of template parameters PARMS. */
3690 tree
3692 {
3693 tree p;
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 /* Don't look through typedefs; we are interested in whether a
3885 parameter pack is actually written in the expression/type we're
3886 looking at, not the target type. */
3888 {
3889 /* But do look at arguments for an alias template. */
3896 }
3898 /* Identify whether this is a parameter pack or not. */
3900 {
3908 /* FALLTHRU */
3910 /* If the placeholder appears in the decl-specifier-seq of a function
3911 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3912 is a pack expansion, the invented template parameter is a template
3913 parameter pack. */
3923 {
3924 /* We don't want to walk into the type of a PARM_DECL,
3925 because we don't want to see the type parameter pack. */
3928 }
3933 {
3934 /* We don't want to walk into the type of a variadic capture proxy,
3935 because we don't want to see the type parameter pack. */
3938 }
3940 {
3942 find_parameter_packs_r,
3945 }
3957 /* Not a parameter pack. */
3959 }
3962 {
3963 /* Add this parameter pack to the list. */
3965 }
3971 /* This switch statement will return immediately if we don't find a
3972 parameter pack. ??? Should some of these be in cp_walk_subtrees? */
3974 {
3976 /* Check the template itself. */
3982 {
3984 /* Ignore the declaration of a capture proxy for a parameter pack. */
3988 /* Since we stop at typedefs above, we need to look through them at
3989 the point of the DECL_EXPR. */
3993 }
4020 {
4021 /* Since we defer implicit capture, look in the parms and body. */
4028 }
4031 {
4032 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
4033 type_pack_expansion_p to false so that any placeholders
4034 within the expression don't get marked as parameter packs. */
4042 }
4051 /* Don't walk into IF_STMT_EXTRA_ARGS. */
4057 }
4060 }
4062 /* Determines if the expression or type T uses any parameter packs. */
4063 tree
4065 {
4074 }
4076 /* Turn ARG, which may be an expression, type, or a TREE_LIST
4077 representation a base-class initializer into a parameter pack
4078 expansion. If all goes well, the resulting node will be an
4079 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
4080 respectively. */
4081 tree
4083 {
4084 tree result;
4093 {
4094 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
4095 class initializer. In this case, the TREE_PURPOSE will be a
4096 _TYPE node (representing the base class expansion we're
4097 initializing) and the TREE_VALUE will be a TREE_LIST
4098 containing the initialization arguments.
4100 The resulting expansion looks somewhat different from most
4101 expansions. Rather than returning just one _EXPANSION, we
4102 return a TREE_LIST whose TREE_PURPOSE is a
4103 TYPE_PACK_EXPANSION containing the bases that will be
4104 initialized. The TREE_VALUE will be identical to the
4105 original TREE_VALUE, which is a list of arguments that will
4106 be passed to each base. We do not introduce any new pack
4107 expansion nodes into the TREE_VALUE (although it is possible
4108 that some already exist), because the TREE_PURPOSE and
4109 TREE_VALUE all need to be expanded together with the same
4110 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
4111 resulting TREE_PURPOSE will mention the parameter packs in
4112 both the bases and the arguments to the bases. */
4113 tree purpose;
4114 tree value;
4117 /* Determine which parameter packs will be used by the base
4118 class expansion. */
4127 {
4130 arg);
4133 }
4136 {
4137 /* Collect the sets of parameter packs used in each of the
4138 initialization arguments. */
4140 {
4141 /* Determine which parameter packs will be expanded in this
4142 argument. */
4145 }
4146 }
4150 /* Create the pack expansion type for the base type. */
4156 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4157 they will rarely be compared to anything. */
4161 }
4166 /* Build the PACK_EXPANSION_* node. */
4167 result = for_types
4172 {
4173 /* Propagate type and const-expression information. */
4176 /* Mark this read now, since the expansion might be length 0. */
4178 }
4179 else
4180 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4181 they will rarely be compared to anything. */
4184 /* Determine which parameter packs will be expanded. */
4191 /* Make sure we found some parameter packs. */
4193 {
4195 {
4198 else
4200 }
4202 }
4208 }
4210 /* Checks T for any "bare" parameter packs, which have not yet been
4211 expanded, and issues an error if any are found. This operation can
4212 only be done on full expressions or types (e.g., an expression
4213 statement, "if" condition, etc.), because we could have expressions like:
4215 foo(f(g(h(args)))...)
4217 where "args" is a parameter pack. check_for_bare_parameter_packs
4218 should not be called for the subexpressions args, h(args),
4219 g(h(args)), or f(g(h(args))), because we would produce erroneous
4220 error messages.
4222 Returns TRUE and emits an error if there were bare parameter packs,
4223 returns FALSE otherwise. */
4224 bool
4226 {
4242 /* It's OK for a lambda to have an unexpanded parameter pack from the
4243 containing context, but do complain about unexpanded capture packs. */
4248 {
4252 }
4255 {
4260 {
4271 else
4276 else
4280 }
4283 }
4286 }
4288 /* Expand any parameter packs that occur in the template arguments in
4289 ARGS. */
4290 tree
4292 {
4301 /* First, determine if we need to expand anything, and the number of
4302 slots we'll need. */
4304 {
4309 {
4313 else
4315 }
4316 else
4317 {
4319 num_result_args++;
4320 }
4321 }
4323 /* If no expansion is necessary, we're done. */
4327 /* Expand arguments. */
4330 non_default_args_count =
4333 {
4336 {
4343 }
4344 else
4345 {
4348 }
4349 }
4353 }
4355 /* Checks if DECL shadows a template parameter.
4357 [temp.local]: A template-parameter shall not be redeclared within its
4358 scope (including nested scopes).
4360 Emits an error and returns TRUE if the DECL shadows a parameter,
4361 returns FALSE otherwise. */
4363 bool
4365 {
4366 tree olddecl;
4368 /* If we're not in a template, we can't possibly shadow a template
4369 parameter. */
4373 /* Figure out what we're shadowing. */
4377 /* If there's no previous binding for this name, we're not shadowing
4378 anything, let alone a template parameter. */
4382 /* If we're not shadowing a template parameter, we're done. Note
4383 that OLDDECL might be an OVERLOAD (or perhaps even an
4384 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4385 node. */
4389 /* We check for decl != olddecl to avoid bogus errors for using a
4390 name inside a class. We check TPFI to avoid duplicate errors for
4391 inline member templates. */
4397 /* Don't complain about the injected class name, as we've already
4398 complained about the class itself. */
4405 else
4410 }
4412 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4413 ORIG_LEVEL, DECL, and TYPE. */
4415 static tree
4419 tree decl,
4420 tree type)
4421 {
4432 }
4434 /* Find the canonical type parameter for the given template type
4435 parameter. Returns the canonical type parameter, which may be TYPE
4436 if no such parameter existed. */
4438 static tree
4440 {
4456 }
4458 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4459 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4460 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4461 new one is created. */
4463 static tree
4465 tsubst_flags_t complain)
4466 {
4471 {
4476 type);
4491 /* Template template parameters need this. */
4494 {
4501 }
4503 /* Attach the TPI to the decl. */
4506 else
4508 }
4511 }
4513 /* Process information from new template parameter PARM and append it
4514 to the LIST being built. This new parameter is a non-type
4515 parameter iff IS_NON_TYPE is true. This new parameter is a
4516 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4517 is in PARM_LOC. */
4519 tree
4522 {
4528 {
4538 }
4545 {
4551 {
4552 /* [temp.param]
4554 The top-level cv-qualifiers on the template-parameter are
4555 ignored when determining its type. */
4560 && !is_parameter_pack
4561 /* If we're in a nested template parameter list, the template
4562 template parameter could be a parameter pack. */
4564 {
4565 /* This template parameter is not a parameter pack, but it
4566 should be. Complain about "bare" parameter packs. */
4569 /* Recover by calling this a parameter pack. */
4571 }
4572 }
4574 /* A template parameter is not modifiable. */
4583 processing_template_decl,
4588 }
4589 else
4590 {
4591 tree t;
4595 {
4597 /* This is for distinguishing between real templates and template
4598 template parameters */
4601 /* any_template_parm_r expects to be able to get the targs of a
4602 DECL_TEMPLATE_RESULT. */
4611 }
4612 else
4613 {
4615 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4618 }
4625 processing_template_decl,
4630 else
4632 }
4636 /* Build requirements for the type/template parameter.
4637 This must be done after SET_DECL_TEMPLATE_PARM_P or
4638 process_template_parm could fail. */
4645 /* Build the parameter node linking the parameter declaration,
4646 its default argument (if any), and its constraints (if any). */
4652 else
4656 }
4658 /* The end of a template parameter list has been reached. Process the
4659 tree list into a parameter vector, converting each parameter into a more
4660 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4661 as PARM_DECLs. */
4663 tree
4665 {
4668 /* Pop the dummy parameter level and add the real one. We do not
4669 morph the dummy parameter in place, as it might have been
4670 captured by a (nested) template-template-parm. */
4673 current_template_parms
4678 {
4684 }
4689 }
4691 // Explicitly indicate the end of the template parameter list. We assume
4692 // that the current template parameters have been constructed and/or
4693 // managed explicitly, as when creating new template template parameters
4694 // from a shorthand constraint.
4695 void
4697 {
4699 }
4701 /* end_template_decl is called after a template declaration is seen. */
4703 void
4705 {
4711 /* This matches the pushlevel in begin_template_parm_list. */
4716 }
4718 /* Takes a TEMPLATE_PARM_P or DECL_TEMPLATE_PARM_P node or a TREE_LIST
4719 thereof, and converts it into an argument suitable to be passed to
4720 the type substitution functions. Note that if the TREE_LIST contains
4721 an error_mark node, the returned argument is error_mark_node. */
4723 tree
4725 {
4736 {
4740 else
4742 }
4748 {
4750 {
4751 /* Turn this argument into a TYPE_ARGUMENT_PACK
4752 with a single element, which expands T. */
4761 }
4762 }
4763 else
4764 {
4766 {
4767 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4768 with a single element, which expands T. */
4778 }
4779 else
4781 }
4783 }
4785 /* Given a single level of template parameters (a TREE_VEC), return it
4786 as a set of template arguments. */
4788 tree
4790 {
4800 }
4802 /* Given a set of template parameters, return them as a set of template
4803 arguments. The template parameters are represented as a TREE_VEC, in
4804 the form documented in cp-tree.h for template arguments. */
4806 tree
4808 {
4809 tree header;
4814 /* If there is only one level of template parameters, we do not
4815 create a TREE_VEC of TREE_VECs. Instead, we return a single
4816 TREE_VEC containing the arguments. */
4821 {
4826 else
4828 }
4831 }
4833 /* Within the declaration of a template, return the currently active
4834 template parameters as an argument TREE_VEC. */
4836 static tree
4838 {
4840 }
4842 /* Return the fully generic arguments for of TMPL, i.e. what
4843 current_template_args would be while parsing it. */
4845 tree
4847 {
4852 /* DECL_TEMPLATE_RESULT doesn't have the arguments we want. For a template
4853 template parameter, it has no TEMPLATE_INFO; for a partial
4854 specialization, it has the arguments for the primary template, and we
4860 }
4862 /* Update the declared TYPE by doing any lookups which were thought to be
4863 dependent, but are not now that we know the SCOPE of the declarator. */
4865 tree
4867 {
4878 /* Don't bother building up the args in this case. */
4880 {
4881 /* tsubst in the args corresponding to the template parameters,
4882 including auto if present. Most things will be unchanged, but
4883 make_typename_type and tsubst_qualified_id will resolve
4884 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4887 tree pushed;
4889 {
4893 }
4898 }
4904 {
4907 else
4909 }
4911 }
4913 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4914 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4915 the new template is a member template. */
4917 static tree
4919 {
4930 }
4932 struct template_parm_data
4933 {
4934 /* The level of the template parameters we are currently
4935 processing. */
4938 /* The index of the specialization argument we are currently
4939 processing. */
4942 /* An array whose size is the number of template parameters. The
4943 elements are nonzero if the parameter has been used in any one
4944 of the arguments processed so far. */
4947 /* An array whose size is the number of template arguments. The
4948 elements are nonzero if the argument makes use of template
4949 parameters of this level. */
4951 };
4953 /* Subroutine of push_template_decl used to see if each template
4954 parameter in a partial specialization is used in the explicit
4955 argument list. If T is of the LEVEL given in DATA (which is
4956 treated as a template_parm_data*), then DATA->PARMS is marked
4957 appropriately. */
4959 static int
4961 {
4969 {
4972 }
4974 /* In C++17 the type of a non-type argument is a deduced context. */
4979 data,
4980 NULL,
4983 /* Return zero so that for_each_template_parm will continue the
4984 traversal of the tree; we want to mark *every* template parm. */
4986 }
4988 /* Process the partial specialization DECL. */
4990 static tree
4992 {
4999 tree inner_parms;
5000 tree inst;
5010 /* A concept cannot be specialized. */
5012 {
5015 }
5020 /* We check that each of the template parameters given in the
5021 partial specialization is used in the argument list to the
5022 specialization. For example:
5024 template <class T> struct S;
5025 template <class T> struct S<T*>;
5027 The second declaration is OK because `T*' uses the template
5028 parameter T, whereas
5030 template <class T> struct S<int>;
5032 is no good. Even trickier is:
5034 template <class T>
5035 struct S1
5036 {
5037 template <class U>
5038 struct S2;
5039 template <class U>
5040 struct S2<T>;
5041 };
5043 The S2<T> declaration is actually invalid; it is a
5044 full-specialization. Of course,
5046 template <class U>
5047 struct S2<T (*)(U)>;
5049 or some such would have been OK. */
5057 {
5062 NULL,
5064 }
5067 {
5068 /* One of the template parms was not used in a deduced context in the
5069 specialization. */
5071 {
5075 }
5079 }
5084 /* [temp.class.spec]
5086 The argument list of the specialization shall not be identical to
5087 the implicit argument list of the primary template. */
5088 tree main_args
5091 && (!flag_concepts
5093 {
5096 "any template arguments; to define the primary template, "
5098 else
5100 "template arguments and is not more constrained than "
5101 "the primary template; to define the primary template, "
5104 }
5106 /* A partial specialization that replaces multiple parameters of the
5107 primary template with a pack expansion is less specialized for those
5108 parameters. */
5110 {
5112 "primary template because it replaces multiple parameters "
5115 /* Avoid crash in process_partial_specialization. */
5117 }
5120 {
5123 /* Avoid crash below. */
5125 }
5127 /* If we aren't in a dependent class, we can actually try deduction. */
5129 /* FIXME we should be able to handle a partial specialization of a
5130 partial instantiation, but currently we can't (c++/41727). */
5133 {
5134 auto_diagnostic_group d;
5138 maintmpl);
5139 }
5141 /* [temp.class.spec]
5143 A partially specialized non-type argument expression shall not
5144 involve template parameters of the partial specialization except
5145 when the argument expression is a simple identifier.
5147 The type of a template parameter corresponding to a specialized
5148 non-type argument shall not be dependent on a parameter of the
5149 specialization.
5151 Also, we verify that pack expansions only occur at the
5152 end of the argument list. */
5155 {
5162 {
5163 /* Extract the arguments from the argument pack. We'll be
5164 iterating over these in the following loop. */
5167 }
5170 {
5172 /* Get the Jth argument in the parameter pack. */
5176 {
5177 /* Pack expansions must come at the end of the
5178 argument list. */
5181 {
5185 else
5188 }
5189 }
5192 /* We only care about the pattern. */
5198 /* This next two lines are the `argument expression is not just a
5199 simple identifier' condition and also the `specialized
5200 non-type argument' bit. */
5205 {
5209 "template argument %qE involves template "
5211 else
5212 {
5213 /* Look at the corresponding template parameter,
5214 marking which template parameters its type depends
5215 upon. */
5219 {
5220 /* We haven't yet initialized TPD2. Do so now. */
5222 /* The number of parameters here is the number in the
5223 main template, which, as checked in the assertion
5224 above, is NARGS. */
5228 }
5230 /* Mark the template parameters. But this time, we're
5231 looking for the template parameters of the main
5232 template, not in the specialization. */
5239 NULL,
5243 {
5244 /* The type depended on some template parameters.
5245 If they are fully specialized in the
5246 specialization, that's OK. */
5255 "type %qT of template argument %qE depends "
5257 "type %qT of template argument %qE depends "
5259 type,
5260 arg);
5261 }
5262 }
5263 }
5264 }
5265 }
5267 /* We should only get here once. */
5271 // Build the template decl.
5278 /* Give template template parms a DECL_CONTEXT of the template
5279 for which they are a parameter. */
5281 {
5285 }
5288 /* We didn't register this in check_explicit_specialization so we could
5289 wait until the constraints were set. */
5291 else
5301 {
5307 {
5315 "declaration of %qD ambiguates earlier template "
5319 "partial specialization of %qD after instantiation "
5321 }
5322 }
5325 }
5327 /* PARM is a template parameter of some form; return the corresponding
5328 TEMPLATE_PARM_INDEX. */
5330 static tree
5332 {
5345 }
5347 /* Subroutine of fixed_parameter_pack_p below. Look for any template
5348 parameter packs used by the template parameter PARM. */
5350 static void
5352 {
5353 /* A type parm can't refer to another parm. */
5357 {
5361 }
5367 {
5371 else
5373 }
5374 }
5376 /* PARM is a template parameter pack. Return any parameter packs used in
5377 its type or the type of any of its template parameters. If there are
5378 any such packs, it will be instantiated into a fixed template parameter
5379 list by partial instantiation rather than be fully deduced. */
5381 tree
5383 {
5384 /* This can only be true in a member template. */
5387 /* This can only be true for a parameter pack. */
5390 /* A type parm can't refer to another parm. */
5404 }
5406 /* Check that a template declaration's use of default arguments and
5407 parameter packs is not invalid. Here, PARMS are the template
5408 parameters. IS_PRIMARY is true if DECL is the thing declared by
5409 a primary template. IS_PARTIAL is true if DECL is a partial
5410 specialization.
5412 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
5413 function template declaration or a friend class template
5414 declaration. In the function case, 1 indicates a declaration, 2
5415 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
5416 emitted for extraneous default arguments.
5418 Returns TRUE if there were no errors found, FALSE otherwise. */
5420 bool
5423 {
5426 tree parm_level;
5429 /* [temp.param]
5431 A default template-argument shall not be specified in a
5432 function template declaration or a function template definition, nor
5433 in the template-parameter-list of the definition of a member of a
5434 class template. */
5438 /* You can't have a function template declaration in a local
5439 scope, nor you can you define a member of a class template in a
5440 local scope. */
5448 /* A lambda doesn't have an explicit declaration; don't complain
5449 about the parms of the enclosing class. */
5456 /* If this is either a friend defined in the scope of the class
5457 or a member function. */
5463 /* And, if it was a member function, it really was defined in
5464 the scope of the class. */
5467 /* We already checked these parameters when the template was
5468 declared, so there's no need to do it again now. This function
5469 was defined in class scope, but we're processing its body now
5470 that the class is complete. */
5473 /* Core issue 226 (C++0x only): the following only applies to class
5474 templates. */
5477 {
5478 /* [temp.param]
5480 If a template-parameter has a default template-argument, all
5481 subsequent template-parameters shall have a default
5482 template-argument supplied. */
5484 {
5491 {
5501 {
5503 /* For better subsequent error-recovery, we indicate that
5504 there should have been a default argument. */
5507 }
5509 && !is_friend_decl
5510 /* Don't complain about an enclosing partial
5511 specialization. */
5516 /* A fixed parameter pack will be partially
5517 instantiated into a fixed length list. */
5519 {
5520 /* A primary class template, primary variable template
5521 (DR 2032), or alias template can only have one
5522 parameter pack, at the end of the template
5523 parameter list. */
5531 }
5532 }
5533 }
5534 }
5537 || is_partial
5538 || !is_primary
5540 /* For an ordinary class template, default template arguments are
5541 allowed at the innermost level, e.g.:
5542 template <class T = int>
5543 struct S {};
5544 but, in a partial specialization, they're not allowed even
5545 there, as we have in [temp.class.spec]:
5547 The template parameter list of a specialization shall not
5548 contain default template argument values.
5550 So, for a partial specialization, or for a function template
5551 (in C++98/C++03), we look at all of them. */
5552 ;
5553 else
5554 /* But, for a primary class template that is not a partial
5555 specialization we look at all template parameters except the
5556 innermost ones. */
5559 /* Figure out what error message to issue. */
5574 else
5575 /* Per [temp.param]/9, "A default template-argument shall not be
5576 specified in the template-parameter-lists of the definition of
5577 a member of a class template that appears outside of the member's
5578 class.", thus if we aren't handling a member of a class template
5579 there is no need to examine the parameters. */
5583 /* If we're inside a class definition, there's no need to
5584 examine the parameters to the class itself. On the one
5585 hand, they will be checked when the class is defined, and,
5586 on the other, default arguments are valid in things like:
5587 template <class T = double>
5588 struct S { template <class U> void f(U); };
5589 Here the default argument for `S' has no bearing on the
5590 declaration of `f'. */
5592 else
5593 /* Check everything. */
5599 {
5606 {
5611 {
5613 {
5620 }
5622 /* Clear out the default argument so that we are not
5623 confused later. */
5625 }
5626 }
5628 /* At this point, if we're still interested in issuing messages,
5629 they must apply to classes surrounding the object declared. */
5633 }
5636 }
5638 /* Worker for push_template_decl_real, called via
5639 for_each_template_parm. DATA is really an int, indicating the
5640 level of the parameters we are interested in. If T is a template
5641 parameter of that level, return nonzero. */
5643 static int
5645 {
5651 else
5654 }
5656 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5657 DATA is really an int, indicating the innermost outer level of parameters.
5658 If T is a template parameter of that level or further out, return
5659 nonzero. */
5661 static int
5663 {
5669 else
5672 }
5674 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5675 parameters given by current_template_args, or reuses a
5676 previously existing one, if appropriate. Returns the DECL, or an
5677 equivalent one, if it is replaced via a call to duplicate_decls.
5679 If IS_FRIEND is true, DECL is a friend declaration. */
5681 tree
5683 {
5687 /* See if this is a partial specialization. */
5696 /* No surprising friend functions. */
5701 tree ctx;
5703 /* For a friend, we want the context of the friend, not
5704 the type of which it is a friend. */
5708 /* In the case of a virtual function, we want the class in which
5709 it is defined. */
5711 else
5712 /* Otherwise, if we're currently defining some class, the DECL
5713 is assumed to be a member of the class. */
5722 /* See if this is a primary template. */
5726 /* A friend template that specifies a class context, i.e.
5727 template <typename T> friend void A<T>::f();
5728 is not primary. */
5729 ;
5731 /* Lambdas are not primary. */
5732 ;
5733 else
5736 /* True if the template is a member template, in the sense of
5737 [temp.mem]. */
5741 {
5749 {
5752 }
5754 {
5756 {
5759 }
5761 {
5762 /* [temp.mem]
5764 A destructor shall not be a member template. */
5768 }
5775 {
5776 /* [basic.stc.dynamic.allocation]
5778 An allocation function can be a function
5779 template. ... Template allocation functions shall
5780 have two or more parameters. */
5783 }
5784 }
5787 {
5788 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5791 {
5797 }
5798 }
5801 /* alias-declaration */
5807 else
5808 {
5811 }
5812 }
5819 /* Check to see that the rules regarding the use of default
5820 arguments are not being violated. We check args for a friend
5821 functions when we know whether it's a definition, introducing
5822 declaration or re-declaration. */
5827 /* Ensure that there are no parameter packs in the type of this
5828 declaration that have not been expanded. */
5830 {
5831 /* Check each of the arguments individually to see if there are
5832 any bare parameter packs. */
5838 {
5841 {
5842 /* This is a PARM_DECL that contains unexpanded parameter
5843 packs. We have already complained about this in the
5844 check_for_bare_parameter_packs call, so just replace
5845 these types with ERROR_MARK_NODE. */
5848 }
5852 }
5854 /* Check for bare parameter packs in the return type and the
5855 exception specifiers. */
5857 /* Errors were already issued, set return type to int
5858 as the frontend doesn't expect error_mark_node as
5859 the return type. */
5863 }
5867 {
5870 }
5879 {
5880 /* Does not get a template head. */
5883 }
5890 {
5895 /* If DECL is a TYPE_DECL for a class-template, then there won't
5896 be DECL_LANG_SPECIFIC. The information equivalent to
5897 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5901 {
5902 /* Since a template declaration already existed for this
5903 class-type, we must be redeclaring it here. Make sure
5904 that the redeclaration is valid. */
5906 current_template_parms,
5908 /* We don't need to create a new TEMPLATE_DECL; just use the
5909 one we already had. */
5911 }
5912 else
5913 {
5915 member_template_p);
5920 {
5921 /* A specialization of a member template of a template
5922 class. */
5926 }
5927 }
5928 }
5929 else
5930 {
5936 {
5939 }
5947 {
5948 /* The declaration is a specialization of a member
5949 template, declared outside the class. Therefore, the
5950 innermost template arguments will be NULL, so we
5951 replace them with the arguments determined by the
5952 earlier call to check_explicit_specialization. */
5955 tree new_tmpl
5957 member_template_p);
5965 args,
5968 }
5970 /* Make sure the template headers we got make sense. */
5975 {
5980 }
5981 else
5983 {
5988 {
5992 else
5996 /* Avoid crash in import_export_decl. */
5999 }
6004 /* Can happen in erroneous input. */
6006 else
6008 }
6010 /* Check that the parms are used in the appropriate qualifying scopes
6011 in the declarator. */
6015 {
6021 /* Avoid crash in import_export_decl. */
6024 }
6025 }
6030 {
6031 /* Push template declarations for global functions and types.
6032 Note that we do not try to push a global template friend
6033 declared in a template class; such a thing may well depend on
6034 the template parameters of the class and we'll push it when
6035 instantiating the befriending class. */
6038 {
6043 /* pushdecl may have found an existing template. */
6045 {
6048 }
6049 }
6050 }
6052 /* The type may have been completed, or (erroneously) changed. */
6056 {
6058 {
6063 /* Give template template parms a DECL_CONTEXT of the template
6064 for which they are a parameter. */
6067 {
6071 }
6075 {
6078 {
6079 /* ??? Why don't we do this here for all templates? */
6082 }
6085 }
6086 }
6088 /* The DECL_TI_ARGS of DECL contains full set of arguments
6089 referring wback to its most general template. If TMPL is a
6090 specialization, ARGS may only have the innermost set of
6091 arguments. Add the missing argument levels if necessary. */
6099 else
6100 {
6103 }
6104 }
6107 && !is_friend
6110 /* Set DECL_COMDAT on template instantiations; if we force
6111 them to be emitted by explicit instantiation,
6112 mark_needed will tell cgraph to do the right thing. */
6118 }
6120 /* FN is an inheriting constructor that inherits from the constructor
6121 template INHERITED; turn FN into a constructor template with a matching
6122 template header. */
6124 tree
6126 {
6127 tree inner_parms
6130 tree parms
6139 }
6141 /* Called when a class template TYPE is redeclared with the indicated
6142 template PARMS, e.g.:
6144 template <class T> struct S;
6145 template <class T> struct S {}; */
6147 bool
6149 {
6150 tree tmpl;
6151 tree tmpl_parms;
6155 {
6158 }
6162 /* The type is nested in some template class. Nothing to worry
6163 about here; there are no new template parameters for the nested
6164 type. */
6168 {
6170 tmpl);
6172 }
6178 {
6188 }
6191 {
6192 tree tmpl_parm;
6193 tree parm;
6194 tree tmpl_default;
6195 tree parm_default;
6209 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
6210 TEMPLATE_DECL. */
6220 {
6221 auto_diagnostic_group d;
6225 }
6227 /* The parameters can be declared to introduce different
6228 constraints. */
6232 {
6233 auto_diagnostic_group d;
6239 }
6242 {
6243 /* We have in [temp.param]:
6245 A template-parameter may not be given default arguments
6246 by two different declarations in the same scope. */
6247 auto_diagnostic_group d;
6252 }
6255 /* Update the previous template parameters (which are the ones
6256 that will really count) with the new default value. */
6259 /* Update the new parameters, too; they'll be used as the
6260 parameters for any members. */
6263 /* Give each template template parm in this redeclaration a
6264 DECL_CONTEXT of the template for which they are a parameter. */
6266 {
6269 }
6273 }
6279 /* Two classes with different constraints declare different entities. */
6281 {
6282 auto_diagnostic_group d;
6288 }
6291 }
6293 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
6294 to be used when the caller has already checked
6295 (processing_template_decl
6296 && !instantiation_dependent_expression_p (expr)
6297 && potential_constant_expression (expr))
6298 and cleared processing_template_decl. */
6300 tree
6302 {
6305 complain,
6309 }
6311 /* Simplify EXPR if it is a non-dependent expression. Returns the
6312 (possibly simplified) expression. */
6314 tree
6316 {
6320 /* If we're in a template, but EXPR isn't value dependent, simplify
6321 it. We're supposed to treat:
6323 template <typename T> void f(T[1 + 1]);
6324 template <typename T> void f(T[2]);
6326 as two declarations of the same function, for example. */
6329 {
6330 processing_template_decl_sentinel s;
6332 }
6334 }
6336 tree
6338 {
6340 }
6342 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
6343 an uninstantiated expression. */
6345 tree
6347 {
6351 {
6354 else
6355 {
6356 processing_template_decl_sentinel s;
6358 }
6359 }
6361 }
6363 /* True iff T is a specialization of a variable template. */
6365 bool
6367 {
6372 }
6374 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
6375 template declaration, or a TYPE_DECL for an alias declaration. */
6377 bool
6379 {
6387 }
6389 /* If T is a specialization of an alias template, return it; otherwise return
6390 NULL_TREE. If TRANSPARENT_TYPEDEFS is true, look through other aliases. */
6392 tree
6395 {
6399 /* It's an alias template specialization if it's an alias and its
6400 TYPE_NAME is a specialization of a primary template. */
6402 {
6409 transparent_typedefs);
6410 }
6413 }
6415 /* An alias template is complex from a SFINAE perspective if a template-id
6416 using that alias can be ill-formed when the expansion is not, as with
6417 the void_t template. We determine this by checking whether the
6418 expansion for the alias template uses all its template parameters. */
6420 struct uses_all_template_parms_data
6421 {
6424 };
6426 static int
6428 {
6436 }
6438 /* for_each_template_parm any_fn callback for complex_alias_template_p. */
6440 static int
6442 {
6443 /* An alias template with a pack expansion that expands a pack from the
6444 enclosing class needs to be considered complex, to avoid confusion with
6445 the same pack being used as an argument to the alias's own template
6446 parameter (91966). */
6453 {
6461 }
6463 }
6465 static bool
6467 {
6468 /* A renaming alias isn't complex. */
6472 /* Any other constrained alias is complex. */
6492 }
6494 /* If T is a specialization of a complex alias template with dependent
6495 template-arguments, return it; otherwise return NULL_TREE. If T is a
6496 typedef to such a specialization, return the specialization. */
6498 tree
6500 {
6507 && (any_dependent_template_arguments_p
6512 {
6515 }
6518 }
6520 /* Return the number of innermost template parameters in TMPL. */
6522 static int
6524 {
6527 }
6529 /* Return either TMPL or another template that it is equivalent to under DR
6530 1286: An alias that just changes the name of a template is equivalent to
6531 the other template. */
6533 static tree
6535 {
6538 {
6539 /* Determine if the alias is equivalent to an underlying template. */
6541 /* The underlying type may have been ill-formed. Don't proceed. */
6558 /* If TMPL adds or changes any constraints, it isn't equivalent. I think
6559 it's appropriate to treat a less-constrained alias as equivalent. */
6563 /* Alias is equivalent. Strip it and repeat. */
6565 }
6568 }
6570 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6571 must be a reference-to-function or a pointer-to-function type, as specified
6572 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6573 and check that the resulting function has external linkage. */
6575 static tree
6577 tsubst_flags_t complain)
6578 {
6581 linkage_kind linkage;
6596 /* [temp.arg.nontype]/1
6598 A template-argument for a non-type, non-template template-parameter
6599 shall be one of:
6600 [...]
6601 -- the address of an object or function with external [C++11: or
6602 internal] linkage. */
6606 {
6608 {
6615 else
6618 }
6620 }
6624 {
6626 {
6632 else
6636 }
6638 }
6640 accept:
6642 {
6645 else
6647 }
6652 }
6654 /* Subroutine of convert_nontype_argument.
6655 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6656 Emit an error otherwise. */
6658 static bool
6660 tsubst_flags_t complain)
6661 {
6677 {
6683 else
6685 }
6687 }
6689 /* Returns TRUE iff the address of OP is value-dependent.
6691 14.6.2.4 [temp.dep.temp]:
6692 A non-integral non-type template-argument is dependent if its type is
6693 dependent or it has either of the following forms
6694 qualified-id
6695 & qualified-id
6696 and contains a nested-name-specifier which specifies a class-name that
6697 names a dependent type.
6699 We generalize this to just say that the address of a member of a
6700 dependent class is value-dependent; the above doesn't cover the
6701 address of a static data member named with an unqualified-id. */
6703 static bool
6705 {
6708 /* We could use get_inner_reference here, but there's no need;
6709 this is only relevant for template non-type arguments, which
6710 can only be expressed as &id-expression. */
6712 {
6716 }
6719 }
6721 /* The next set of functions are used for providing helpful explanatory
6722 diagnostics for failed overload resolution. Their messages should be
6723 indented by two spaces for consistency with the messages in
6724 call.c */
6726 static int
6728 {
6730 }
6732 /* Other failure functions should call this one, to provide a single function
6733 for setting a breakpoint on. */
6735 static int
6737 {
6739 }
6741 static int
6743 {
6748 }
6750 static int
6752 {
6758 }
6760 static int
6762 {
6766 }
6768 static int
6770 {
6773 " template parameter %qD is not a parameter pack, but "
6777 }
6779 static int
6781 {
6784 " template argument %qE does not match "
6788 }
6790 static int
6792 {
6796 }
6798 static int
6800 {
6806 }
6808 static int
6810 {
6812 {
6817 else
6819 " deduced conflicting values for non-type parameter "
6821 }
6823 }
6825 static int
6827 {
6830 " variable-sized array type %qT is not "
6832 arg);
6834 }
6836 static int
6838 {
6842 arg);
6844 }
6846 static int
6848 {
6850 {
6856 else
6861 }
6863 }
6865 static int
6867 {
6869 }
6871 static int
6874 {
6876 }
6878 static int
6881 {
6887 }
6889 static int
6892 {
6895 {
6903 }
6905 }
6907 static int
6909 {
6912 " template parameters of a template template argument are "
6915 }
6917 static int
6919 {
6925 }
6927 static int
6929 {
6934 }
6936 /* True if T is a C++20 template parameter object to store the argument for a
6937 template parameter of class type. */
6939 bool
6941 {
6944 }
6946 /* Subroutine of convert_nontype_argument, to check whether EXPR, as an
6947 argument for TYPE, points to an unsuitable object.
6949 Also adjust the type of the index in C++20 array subobject references. */
6951 static bool
6953 {
6955 {
6956 CASE_CONVERT:
6958 complain);
6962 complain);
6965 {
6970 }
6974 {
6980 {
6984 /* Canonicalize array offsets to ptrdiff_t; how they were
6985 written doesn't matter for subobject identity. */
6988 }
6991 {
6994 "%qE is not a valid template argument of type %qT "
6997 }
6999 {
7002 "%qE is not a valid template argument of type %qT "
7006 }
7009 {
7012 "%qE is not a valid template argument of type %qT "
7015 }
7016 /* C++17: For a non-type template-parameter of reference or pointer
7017 type, the value of the constant expression shall not refer to (or
7018 for a pointer type, shall not be the address of):
7019 * a subobject (4.5),
7020 * a temporary object (15.2),
7021 * a string literal (5.13.5),
7022 * the result of a typeid expression (8.2.8), or
7023 * a predefined __func__ variable (11.4.1). */
7025 {
7028 decl);
7030 }
7032 && !(same_type_ignoring_top_level_qualifiers_p
7035 {
7040 }
7042 {
7046 decl);
7048 }
7049 }
7057 else
7058 {
7060 {
7063 "because %qD is a variable, not the address of "
7066 }
7067 else
7068 {
7074 }
7075 }
7076 }
7079 }
7081 /* The template arguments corresponding to template parameter objects of types
7082 that contain pointers to members. */
7086 /* Return a VAR_DECL for the C++20 template parameter object corresponding to
7087 template argument EXPR. */
7089 static tree
7091 {
7096 {
7101 }
7121 {
7122 /* If EXPR contains any PTRMEM_CST, they will get clobbered by
7123 lower_var_init before we're done mangling. So store the original
7124 value elsewhere. */
7127 }
7132 }
7134 /* Return the actual template argument corresponding to template parameter
7135 object VAR. */
7137 tree
7139 {
7143 }
7145 /* Attempt to convert the non-type template parameter EXPR to the
7146 indicated TYPE. If the conversion is successful, return the
7147 converted value. If the conversion is unsuccessful, return
7148 NULL_TREE if we issued an error message, or error_mark_node if we
7149 did not. We issue error messages for out-and-out bad template
7150 parameters, but not simply because the conversion failed, since we
7151 might be just trying to do argument deduction. Both TYPE and EXPR
7152 must be non-dependent.
7154 The conversion follows the special rules described in
7155 [temp.arg.nontype], and it is much more strict than an implicit
7156 conversion.
7158 This function is called twice for each template argument (see
7159 lookup_template_class for a more accurate description of this
7160 problem). This means that we need to handle expressions which
7161 are not valid in a C++ source, but can be created from the
7162 first call (for instance, casts to perform conversions). These
7163 hacks can go away after we fix the double coercion problem. */
7165 static tree
7167 {
7168 tree expr_type;
7171 /* Detect immediately string literals as invalid non-type argument.
7172 This special-case is not needed for correctness (we would easily
7173 catch this later), but only to provide better diagnostic for this
7174 common user mistake. As suggested by DR 100, we do not mention
7175 linkage issues in the diagnostic as this is not the point. */
7177 {
7183 }
7185 /* Add the ADDR_EXPR now for the benefit of
7186 value_dependent_expression_p. */
7189 {
7193 }
7195 /* If we are in a template, EXPR may be non-dependent, but still
7196 have a syntactic, rather than semantic, form. For example, EXPR
7197 might be a SCOPE_REF, rather than the VAR_DECL to which the
7198 SCOPE_REF refers. Preserving the qualifying scope is necessary
7199 so that access checking can be performed when the template is
7200 instantiated -- but here we need the resolved form so that we can
7201 convert the argument. */
7213 /* If the argument is non-dependent, perform any conversions in
7214 non-dependent context as well. */
7223 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
7224 to a non-type argument of "nullptr". */
7228 /* In C++11, integral or enumeration non-type template arguments can be
7229 arbitrary constant expressions. Pointer and pointer to
7230 member arguments can be general constant expressions that evaluate
7231 to a null value, but otherwise still need to be of a specific form. */
7233 {
7235 /* A PTRMEM_CST is already constant, and a valid template
7236 argument for a parameter of pointer to member type, we just want
7237 to leave it in that form rather than lower it to a
7241 {
7242 /* C++17: A template-argument for a non-type template-parameter shall
7243 be a converted constant expression (8.20) of the type of the
7244 template-parameter. */
7247 /* Make sure we return NULL_TREE only if we have really issued
7248 an error, as described above. */
7251 {
7254 }
7258 }
7260 {
7266 }
7267 }
7271 else
7274 /* HACK: Due to double coercion, we can get a
7275 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
7276 which is the tree that we built on the first call (see
7277 below when coercing to reference to object or to reference to
7278 function). We just strip everything and get to the arg.
7279 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
7280 for examples. */
7282 {
7288 {
7289 /* ??? Maybe we could use convert_from_reference here, but we
7290 would need to relax its constraints because the NOP_EXPR
7291 could actually change the type to something more cv-qualified,
7292 and this is not folded by convert_from_reference. */
7297 && (same_type_ignoring_top_level_qualifiers_p
7300 {
7303 }
7304 }
7305 }
7307 /* [temp.arg.nontype]/5, bullet 1
7309 For a non-type template-parameter of integral or enumeration type,
7310 integral promotions (_conv.prom_) and integral conversions
7311 (_conv.integral_) are applied. */
7314 {
7316 {
7321 }
7326 /* Notice that there are constant expressions like '4 % 0' which
7327 do not fold into integer constants. */
7329 {
7331 {
7335 else
7341 /* else cxx_constant_value complained but gave us
7342 a real constant, so go ahead. */
7344 {
7345 /* Some assemble time constant expressions like
7346 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
7347 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
7348 as we can emit them into .rodata initializers of
7349 variables, yet they can't fold into an INTEGER_CST at
7350 compile time. Refuse them here. */
7355 }
7356 }
7357 else
7359 }
7361 /* Avoid typedef problems. */
7364 }
7365 /* [temp.arg.nontype]/5, bullet 2
7367 For a non-type template-parameter of type pointer to object,
7368 qualification conversions (_conv.qual_) and the array-to-pointer
7369 conversion (_conv.array_) are applied. */
7371 {
7374 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
7375 decay_conversion or an explicit cast. If it's a problematic cast,
7376 we'll complain about it below. */
7378 {
7383 {
7386 }
7387 }
7389 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
7391 A template-argument for a non-type, non-template template-parameter
7392 shall be one of: [...]
7394 -- the name of a non-type template-parameter;
7395 -- the address of an object or function with external linkage, [...]
7396 expressed as "& id-expression" where the & is optional if the name
7397 refers to a function or array, or if the corresponding
7398 template-parameter is a reference.
7400 Here, we do not care about functions, as they are invalid anyway
7401 for a parameter of type pointer-to-object. */
7404 /* Non-type template parameters are OK. */
7405 ;
7410 /* Other values, like integer constants, might be valid
7411 non-type arguments of some other type. */
7421 }
7422 /* [temp.arg.nontype]/5, bullet 3
7424 For a non-type template-parameter of type reference to object, no
7425 conversions apply. The type referred to by the reference may be more
7426 cv-qualified than the (otherwise identical) type of the
7427 template-argument. The template-parameter is bound directly to the
7428 template-argument, which must be an lvalue. */
7430 {
7432 expr_type))
7436 {
7441 }
7444 {
7449 }
7451 /* [temp.arg.nontype]/1
7453 A template-argument for a non-type, non-template template-parameter
7454 shall be one of: [...]
7456 -- the address of an object or function with external linkage. */
7459 {
7462 {
7465 "because a reference variable does not have a constant "
7468 }
7469 }
7472 /* OK, dependent reference. We don't want to ask whether a DECL is
7474 else
7475 {
7480 }
7484 }
7485 /* [temp.arg.nontype]/5, bullet 4
7487 For a non-type template-parameter of type pointer to function, only
7488 the function-to-pointer conversion (_conv.func_) is applied. If the
7489 template-argument represents a set of overloaded functions (or a
7490 pointer to such), the matching function is selected from the set
7491 (_over.over_). */
7493 {
7494 /* If the argument is a template-id, we might not have enough
7495 context information to decay the pointer. */
7497 {
7501 }
7504 /* Null pointer values are OK in C++11. */
7510 }
7511 /* [temp.arg.nontype]/5, bullet 5
7513 For a non-type template-parameter of type reference to function, no
7514 conversions apply. If the template-argument represents a set of
7515 overloaded functions, the matching function is selected from the set
7516 (_over.over_). */
7518 {
7520 {
7522 {
7527 }
7529 }
7534 }
7535 /* [temp.arg.nontype]/5, bullet 6
7537 For a non-type template-parameter of type pointer to member function,
7538 no conversions apply. If the template-argument represents a set of
7539 overloaded member functions, the matching member function is selected
7540 from the set (_over.over_). */
7542 {
7547 /* [temp.arg.nontype] bullet 1 says the pointer to member
7548 expression must be a pointer-to-member constant. */
7553 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
7554 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
7557 }
7558 /* [temp.arg.nontype]/5, bullet 7
7560 For a non-type template-parameter of type pointer to data member,
7561 qualification conversions (_conv.qual_) are applied. */
7563 {
7564 /* [temp.arg.nontype] bullet 1 says the pointer to member
7565 expression must be a pointer-to-member constant. */
7573 }
7575 {
7577 {
7582 }
7584 }
7586 {
7587 /* Replace the argument with a reference to the corresponding template
7588 parameter object. */
7593 }
7594 /* A template non-type parameter must be one of the above. */
7595 else
7598 /* Sanity check: did we actually convert the argument to the
7599 right type? */
7603 }
7605 /* Subroutine of coerce_template_template_parms, which returns 1 if
7606 PARM_PARM and ARG_PARM match using the rule for the template
7607 parameters of template template parameters. Both PARM and ARG are
7608 template parameters; the rest of the arguments are the same as for
7609 coerce_template_template_parms.
7610 */
7611 static int
7613 tree arg,
7614 tsubst_flags_t complain,
7615 tree in_decl,
7616 tree outer_args)
7617 {
7626 {
7628 /* We encounter instantiations of templates like
7629 template <template <template <class> class> class TT>
7630 class C; */
7631 {
7638 }
7639 /* Fall through. */
7644 /* Argument is a parameter pack but parameter is not. */
7649 /* The tsubst call is used to handle cases such as
7651 template <int> class C {};
7652 template <class T, template <T> class TT> class D {};
7653 D<int, C> d;
7655 i.e. the parameter list of TT depends on earlier parameters. */
7657 {
7662 }
7666 /* Argument is a parameter pack but parameter is not. */
7673 }
7676 }
7678 /* Coerce template argument list ARGLIST for use with template
7679 template-parameter TEMPL. */
7681 static tree
7683 tsubst_flags_t complain)
7684 {
7685 /* Consider an example where a template template parameter declared as
7687 template <class T, class U = std::allocator<T> > class TT
7689 The template parameter level of T and U are one level larger than
7690 of TT. To proper process the default argument of U, say when an
7691 instantiation `TT<int>' is seen, we need to build the full
7692 arguments containing {int} as the innermost level. Outer levels,
7693 available when not appearing as default template argument, can be
7694 obtained from the arguments of the enclosing template.
7696 Suppose that TT is later substituted with std::vector. The above
7697 instantiation is `TT<int, std::allocator<T> >' with TT at
7698 level 1, and T at level 2, while the template arguments at level 1
7699 becomes {std::vector} and the inner level 2 is {int}. */
7705 {
7706 /* This is an argument of the current template, so we haven't set
7707 DECL_CONTEXT yet. */
7708 tree relevant_template_parms;
7710 /* Parameter levels that are greater than the level of the given
7711 template template parm are irrelevant. */
7718 }
7725 complain,
7728 }
7730 /* A cache of template template parameters with match-all default
7731 arguments. */
7734 /* T is a bound template template-parameter. Copy its arguments into default
7735 arguments of the template template-parameter's template parameters. */
7737 static tree
7739 {
7762 {
7765 {
7768 }
7769 }
7773 }
7775 /* ARG is a bound potential template template-argument, and PARGS is a list
7776 of arguments for the corresponding template template-parameter. Adjust
7777 PARGS as appropriate for application to ARG's template, and if ARG is a
7778 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7779 arguments to the template template parameter. */
7781 static tree
7783 {
7787 {
7788 /* When comparing two template template-parameters in partial ordering,
7789 rewrite the one currently being used as an argument to have default
7790 arguments for all parameters. */
7796 }
7797 else
7798 {
7799 tree aparms
7804 }
7807 }
7809 /* Subroutine of unify for the case when PARM is a
7810 BOUND_TEMPLATE_TEMPLATE_PARM. */
7812 static int
7815 {
7819 /* The template template parm might be variadic and the argument
7820 not, so flatten both argument lists. */
7825 {
7826 /* In keeping with P0522R0, adjust P's template arguments
7827 to apply to A's template; then flatten it again. */
7835 /* If the P0522 adjustment eliminated a pack expansion, deduce
7836 empty packs. */
7842 }
7843 else
7844 {
7845 /* Deduce arguments T, i from TT<T> or TT<i>.
7846 We check each element of PARMVEC and ARGVEC individually
7847 rather than the whole TREE_VEC since they can have
7848 different number of elements, which is allowed under N2555. */
7852 /* Check if the parameters end in a pack, making them
7853 variadic. */
7860 /* If the template argument list of P contains a pack
7861 expansion that is not the last template argument, the
7862 entire template argument list is a non-deduced
7863 context. */
7881 DEDUCE_EXACT,
7884 }
7887 }
7889 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7890 template template parameters. Both PARM_PARMS and ARG_PARMS are
7891 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7892 or PARM_DECL.
7894 Consider the example:
7895 template <class T> class A;
7896 template<template <class U> class TT> class B;
7898 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7899 the parameters to A, and OUTER_ARGS contains A. */
7901 static int
7903 tree arg_parms,
7904 tsubst_flags_t complain,
7905 tree in_decl,
7906 tree outer_args)
7907 {
7919 {
7920 /* P0522R0: A template template-parameter P is at least as specialized as
7921 a template template-argument A if, given the following rewrite to two
7922 function templates, the function template corresponding to P is at
7923 least as specialized as the function template corresponding to A
7924 according to the partial ordering rules for function templates
7925 ([temp.func.order]). Given an invented class template X with the
7926 template parameter list of A (including default arguments):
7928 * Each of the two function templates has the same template parameters,
7929 respectively, as P or A.
7931 * Each function template has a single function parameter whose type is
7932 a specialization of X with template arguments corresponding to the
7933 template parameters from the respective function template where, for
7934 each template parameter PP in the template parameter list of the
7935 function template, a corresponding template argument AA is formed. If
7936 PP declares a parameter pack, then AA is the pack expansion
7937 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7939 If the rewrite produces an invalid type, then P is not at least as
7940 specialized as A. */
7942 /* So coerce P's args to apply to A's parms, and then deduce between A's
7943 args and the converted args. If that succeeds, A is at least as
7944 specialized as P, so they match.*/
7952 {
7958 }
7959 }
7961 /* Determine whether we have a parameter pack at the end of the
7962 template template parameter's template parameter list. */
7964 {
7971 {
7985 }
7986 }
7992 /* Check all of the template parameters except the parameter pack at
7993 the end (if any). */
7995 {
8004 outer_args))
8007 }
8010 {
8011 /* Check each of the template parameters in the template
8012 argument against the template parameter pack at the end of
8013 the template template parameter. */
8020 {
8027 outer_args))
8029 }
8030 }
8033 }
8035 /* Verifies that the deduced template arguments (in TARGS) for the
8036 template template parameters (in TPARMS) represent valid bindings,
8037 by comparing the template parameter list of each template argument
8038 to the template parameter list of its corresponding template
8039 template parameter, in accordance with DR150. This
8040 routine can only be called after all template arguments have been
8041 deduced. It will return TRUE if all of the template template
8042 parameter bindings are okay, FALSE otherwise. */
8043 bool
8045 {
8049 /* We're dealing with template parms in this process. */
8055 {
8060 {
8065 {
8066 /* Look inside the argument pack. */
8069 }
8072 {
8076 /* Extract the next argument from the argument
8077 pack. */
8081 /* Look at the pattern of the pack expansion. */
8084 /* Extract the template parameters from the template
8085 argument. */
8091 /* Verify that we can coerce the template template
8092 parameters from the template argument to the template
8093 parameter. This requires an exact match. */
8095 && !coerce_template_template_parms
8097 targ_parms,
8098 tf_none,
8099 tparm,
8100 targs))
8101 {
8104 }
8105 }
8106 }
8107 }
8109 out:
8113 }
8115 /* Since type attributes aren't mangled, we need to strip them from
8116 template type arguments. */
8118 tree
8120 {
8130 }
8132 /* And from inside dependent non-type arguments like sizeof(Type). */
8134 static tree
8136 {
8146 }
8148 /* A template declaration can be substituted for a constrained
8149 template template parameter only when the argument is no more
8150 constrained than the parameter. */
8152 static bool
8154 {
8157 /* For now, allow constrained template template arguments
8158 and unconstrained template template parameters. */
8162 /* If the template parameter is constrained, we need to rewrite its
8163 constraints in terms of the ARG's template parameters. This ensures
8164 that all of the template parameter types will have the same depth.
8166 Note that this is only valid when coerce_template_template_parm is
8167 true for the innermost template parameters of PARM and ARG. In other
8168 words, because coercion is successful, this conversion will be valid. */
8171 {
8178 }
8181 }
8183 // Convert a placeholder argument into a binding to the original
8184 // parameter. The original parameter is saved as the TREE_TYPE of
8185 // ARG.
8188 {
8191 }
8193 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
8194 because one of them is dependent. But we need to represent the
8195 conversion for the benefit of cp_tree_equal. */
8197 static tree
8199 {
8200 /* Auto parms get no conversion. */
8203 /* We don't need or want to add this conversion now if we're going to use the
8204 argument for deduction. */
8216 }
8218 /* Convert the indicated template ARG as necessary to match the
8219 indicated template PARM. Returns the converted ARG, or
8220 error_mark_node if the conversion was unsuccessful. Error and
8221 warning messages are issued under control of COMPLAIN. This
8222 conversion is for the Ith parameter in the parameter list. ARGS is
8223 the full set of template arguments deduced so far. */
8225 static tree
8227 tree arg,
8228 tree args,
8229 tsubst_flags_t complain,
8231 tree in_decl)
8232 {
8233 tree orig_arg;
8234 tree val;
8240 /* Trivially convert placeholders. */
8249 {
8250 /* The template argument was the name of some
8251 member function. That's usually
8252 invalid, but static members are OK. In any
8253 case, grab the underlying fields/functions
8254 and issue an error later if required. */
8256 }
8264 /* When determining whether an argument pack expansion is a template,
8265 look at the pattern. */
8269 /* Deal with an injected-class-name used as a template template arg. */
8271 {
8274 {
8284 }
8285 }
8287 is_tmpl_type =
8303 {
8305 {
8309 }
8312 "to refer to a type member of a template parameter, "
8317 typename_type,
8318 complain);
8321 }
8323 {
8325 {
8327 {
8332 {
8333 /* The template argument is a type, but we're expecting
8334 an expression. */
8339 /* [temp.arg]/2: "In a template-argument, an ambiguity
8340 between a type-id and an expression is resolved to a
8341 type-id, regardless of the form of the corresponding
8342 template-parameter." So give the user a clue. */
8345 "for non-type template parameter is treated as "
8347 }
8351 else
8354 }
8355 }
8357 }
8359 {
8361 {
8368 else
8371 }
8373 }
8376 /* We already did the appropriate conversion when packing args. */
8379 {
8381 {
8383 /* The number of argument required is not known yet.
8384 Just accept it for now. */
8386 else
8387 {
8389 tree argparm;
8391 /* Strip alias templates that are equivalent to another
8392 template. */
8398 args))
8399 {
8402 /* TEMPLATE_TEMPLATE_PARM node is preferred over
8403 TEMPLATE_DECL. */
8405 {
8410 }
8411 }
8412 else
8413 {
8415 {
8422 }
8425 }
8427 // Check that the constraints are compatible before allowing the
8428 // substitution.
8431 {
8433 {
8439 }
8441 }
8442 }
8443 }
8444 else
8446 /* We only form one instance of each template specialization.
8447 Therefore, if we use a non-canonical variant (i.e., a
8448 typedef), any future messages referring to the type will use
8449 the typedef, which is confusing if those future uses do not
8450 themselves also use the typedef. */
8453 }
8454 else
8455 {
8460 /* We don't have enough levels of args to do any substitution. This
8463 {
8467 }
8468 else
8479 /* We used to call digest_init here. However, digest_init
8480 will report errors, which we don't want when complain
8481 is zero. More importantly, digest_init will try too
8482 hard to convert things: for example, `0' should not be
8483 converted to pointer type at this point according to
8484 the standard. Accepting this is not merely an
8485 extension, since deciding whether or not these
8486 conversions can occur is part of determining which
8487 function template to call, or whether a given explicit
8488 argument specification is valid. */
8490 else
8491 {
8494 }
8505 {
8506 /* Reject template arguments that are references to built-in
8507 functions with no library fallbacks. */
8516 }
8519 {
8520 /* Strip typedefs from the SCOPE_REF. */
8523 complain);
8526 }
8527 }
8530 }
8532 /* Coerces the remaining template arguments in INNER_ARGS (from
8533 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
8534 Returns the coerced argument pack. PARM_IDX is the position of this
8535 parameter in the template parameter list. ARGS is the original
8536 template argument list. */
8537 static tree
8540 tree args,
8541 tree inner_args,
8543 tree new_args,
8545 tree in_decl,
8546 tsubst_flags_t complain)
8547 {
8550 tree packed_args;
8551 tree argument_pack;
8558 {
8559 /* When the template parameter is a non-type template parameter pack
8560 or template template parameter pack whose type or template
8561 parameters use parameter packs, we know exactly how many arguments
8562 we are looking for. Build a vector of the instantiated decls for
8563 these template parameters in PACKED_PARMS. */
8564 /* We can't use make_pack_expansion here because it would interpret a
8565 _DECL as a use rather than a declaration. */
8579 /* If we're doing a partial instantiation of a member template,
8580 verify that all of the types used for the non-type
8581 template parameter pack are, in fact, valid for non-type
8582 template parameters. */
8585 {
8588 {
8593 }
8594 /* We don't know how many args we have yet, just
8595 use the unconverted ones for now. */
8597 }
8600 }
8601 /* Check if we have a placeholder pack, which indicates we're
8602 in the context of a introduction list. In that case we want
8603 to match this pack to the single placeholder. */
8607 {
8610 }
8611 else
8614 /* Convert the remaining arguments, which will be a part of the
8615 parameter pack "parm". */
8618 {
8624 {
8625 /* Once we've packed as many args as we have types, stop. */
8629 /* We don't know how many args we have yet, just
8630 use the unconverted ones for now. */
8632 else
8634 }
8637 {
8640 }
8641 else
8644 in_decl);
8648 }
8652 {
8657 }
8662 else
8663 {
8666 }
8673 }
8675 /* Returns the number of pack expansions in the template argument vector
8676 ARGS. */
8678 static int
8680 {
8685 {
8689 }
8691 }
8693 /* Convert all template arguments to their appropriate types, and
8694 return a vector containing the innermost resulting template
8695 arguments. If any error occurs, return error_mark_node. Error and
8696 warning messages are issued under control of COMPLAIN.
8698 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8699 for arguments not specified in ARGS. Otherwise, if
8700 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
8701 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
8702 USE_DEFAULT_ARGS is false, then all arguments must be specified in
8703 ARGS. */
8705 static tree
8707 tree args,
8708 tree in_decl,
8709 tsubst_flags_t complain,
8712 {
8714 tree orig_inner_args;
8715 tree inner_args;
8716 tree new_args;
8717 tree new_inner_args;
8719 /* When used as a boolean value, indicates whether this is a
8720 variadic template parameter list. Since it's an int, we can also
8721 subtract it from nparms to get the number of non-variadic
8722 parameters. */
8727 /* Adjustment to nparms for fixed parameter packs. */
8732 /* Likewise for parameters with default arguments. */
8740 /* Determine if there are any parameter packs or default arguments. */
8742 {
8750 }
8753 /* If there are no parameters that follow a parameter pack, we need to
8754 expand any argument packs so that we can deduce a parameter pack from
8755 some non-packed args followed by an argument pack, as in variadic85.C.
8756 If there are such parameters, we need to leave argument packs intact
8757 so the arguments are assigned properly. This can happen when dealing
8758 with a nested class inside a partial specialization of a class
8759 template, as in variadic92.C, or when deducing a template parameter pack
8760 from a sub-declarator, as in variadic114.C. */
8764 /* Count any pack expansion args. */
8770 && require_all_args
8771 && !variadic_args_p
8772 && (!use_default_args
8775 {
8776 bad_nargs:
8778 {
8780 {
8784 }
8785 else
8792 }
8795 }
8796 /* We can't pass a pack expansion to a non-pack parameter of an alias
8797 template (DR 1430). */
8801 && variadic_args_p
8803 {
8805 {
8807 {
8813 {
8816 "pack expansion argument for non-pack parameter "
8818 else
8820 "pack expansion argument for non-pack parameter "
8824 }
8825 }
8827 found:;
8828 }
8830 }
8832 /* We need to evaluate the template arguments, even though this
8833 template-id may be nested within a "sizeof". */
8834 cp_evaluated ev;
8840 {
8841 tree arg;
8842 tree parm;
8844 /* Get the Ith template parameter. */
8848 {
8851 }
8853 /* Calculate the next argument. */
8856 else
8862 {
8863 /* Some arguments will be placed in the
8864 template parameter pack PARM. */
8871 {
8872 /* We don't know how many args we have yet, just use the
8873 unconverted (and still packed) ones for now. */
8877 }
8881 /* Store this argument. */
8883 {
8884 lost++;
8885 /* We are done with all of the arguments. */
8888 }
8889 else
8890 {
8894 {
8897 }
8898 }
8901 }
8903 {
8905 {
8906 /* "If every valid specialization of a variadic template
8907 requires an empty template parameter pack, the template is
8908 ill-formed, no diagnostic required." So check that the
8909 pattern works with this parameter. */
8914 in_decl);
8916 {
8921 }
8923 /* Recover from missing typename. */
8927 /* We don't know how many args we have yet, just
8928 use the unconverted ones for now. */
8932 }
8933 }
8935 {
8936 /* There must be a default arg in this case. */
8939 /* The position of the first default template argument,
8940 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8941 Record that. */
8945 }
8946 else
8950 {
8953 }
8955 {
8956 /* This can occur if there was an error in the template
8957 parameter list itself (which we would already have
8958 reported) that we are trying to recover from, e.g., a class
8959 template with a parameter list such as
8960 template<typename..., typename> (cpp0x/variadic150.C). */
8963 /* This can also happen with a fixed parameter pack (71834). */
8966 }
8967 else
8973 lost++;
8976 }
8979 {
8980 /* If we had fixed parameter packs, we didn't know how many arguments we
8981 actually needed earlier; now we do. */
8985 }
8988 {
8989 /* We had some pack expansion arguments that will only work if the packs
8990 are empty, but wait until instantiation time to complain.
8991 See variadic-ttp3.C. */
8993 /* Except that we can't provide empty packs to alias templates or
8994 concepts when there are no corresponding parameters. Basically,
8995 we can get here with this:
8997 template<typename T> concept C = true;
8999 template<typename... Args>
9000 requires C<Args...>
9001 void f();
9003 When parsing C<Args...>, we try to form a concept check of
9004 C<?, Args...>. Without the extra check for substituting an empty
9005 pack past the last parameter, we can accept the check as valid.
9007 FIXME: This may be valid for alias templates (but I doubt it).
9009 FIXME: The error could be better also. */
9011 {
9016 }
9027 }
9030 {
9033 }
9040 }
9042 /* Convert all template arguments to their appropriate types, and
9043 return a vector containing the innermost resulting template
9044 arguments. If any error occurs, return error_mark_node. Error and
9045 warning messages are not issued.
9047 Note that no function argument deduction is performed, and default
9048 arguments are used to fill in unspecified arguments. */
9049 tree
9051 {
9053 }
9055 /* Convert all template arguments to their appropriate type, and
9056 instantiate default arguments as needed. This returns a vector
9057 containing the innermost resulting template arguments, or
9058 error_mark_node if unsuccessful. */
9059 tree
9061 tsubst_flags_t complain)
9062 {
9064 }
9066 /* Like coerce_template_parms. If PARMS represents all template
9067 parameters levels, this function returns a vector of vectors
9068 representing all the resulting argument levels. Note that in this
9069 case, only the innermost arguments are coerced because the
9070 outermost ones are supposed to have been coerced already.
9072 Otherwise, if PARMS represents only (the innermost) vector of
9073 parameters, this function returns a vector containing just the
9074 innermost resulting arguments. */
9076 static tree
9078 tree args,
9079 tree in_decl,
9080 tsubst_flags_t complain,
9083 {
9086 tree coerced_args;
9089 {
9091 tree level;
9097 {
9098 tree l;
9102 require_all_args,
9103 use_default_args);
9104 else
9111 }
9112 }
9113 else
9116 require_all_args,
9117 use_default_args);
9119 }
9121 /* Returns true if T is a wrapper to make a C++20 template parameter
9122 object const. */
9124 static bool
9126 {
9132 }
9134 /* Returns 1 if template args OT and NT are equivalent. */
9136 int
9138 {
9152 /* For member templates */
9165 {
9168 /* Don't treat an alias template specialization with dependent
9169 arguments as equivalent to its underlying type when used as a
9170 template argument; we need them to be distinct so that we
9171 substitute into the specialization arguments at instantiation
9172 time. And aliases can't be equivalent without being ==, so
9173 we don't need to look any deeper.
9175 During partial ordering, however, we need to treat them normally so
9176 that we can order uses of the same alias with different
9177 cv-qualification (79960). */
9181 else
9183 }
9184 else
9185 {
9186 /* Try to treat a template non-type argument that has been converted
9187 to the parameter type as equivalent to one that hasn't yet. */
9201 }
9202 }
9204 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
9205 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
9206 NEWARG_PTR with the offending arguments if they are non-NULL. */
9208 int
9212 {
9225 {
9230 {
9236 }
9237 }
9239 }
9243 {
9245 }
9247 /* Implement a freelist interface for objects of type T.
9249 Head is a separate object, rather than a regular member, so that we
9250 can define it as a GTY deletable pointer, which is highly
9251 desirable. A data member could be declared that way, but then the
9252 containing object would implicitly get GTY((user)), which would
9253 prevent us from instantiating freelists as global objects.
9254 Although this way we can create freelist global objects, they're
9255 such thin wrappers that instantiating temporaries at every use
9256 loses nothing and saves permanent storage for the freelist object.
9258 Member functions next, anew, poison and reinit have default
9259 implementations that work for most of the types we're interested
9260 in, but if they don't work for some type, they should be explicitly
9261 specialized. See the comments before them for requirements, and
9262 the example specializations for the tree_list_freelist. */
9264 class freelist
9265 {
9266 /* Return the next object in a chain. We could just do type
9267 punning, but if we access the object with its underlying type, we
9268 avoid strict-aliasing trouble. This needs only work between
9269 poison and reinit. */
9272 /* Return a newly allocated, uninitialized or minimally-initialized
9273 object of type T. Any initialization performed by anew should
9274 either remain across the life of the object and the execution of
9275 poison, or be redone by reinit. */
9278 /* Optionally scribble all over the bits holding the object, so that
9279 they become (mostly?) uninitialized memory. This is called while
9280 preparing to make the object part of the free list. */
9285 #ifdef ENABLE_GC_CHECKING
9286 /* Poison the data, to indicate the data is garbage. */
9289 #endif
9290 /* Let valgrind know the object is free. */
9293 /* Let valgrind know the next portion of the object is available,
9294 but uninitialized. */
9296 }
9298 /* Bring an object that underwent at least one lifecycle after anew
9299 and before the most recent free and poison, back to a usable
9300 state, reinitializing whatever is needed for it to be
9301 functionally equivalent to an object just allocated and returned
9302 by anew. This may poison or clear the next field, used by
9303 freelist housekeeping after poison was called. */
9307 #ifdef ENABLE_GC_CHECKING
9309 #endif
9310 /* Let valgrind know the entire object is available, but
9311 uninitialized. */
9313 }
9315 /* Reference a GTY-deletable pointer that points to the first object
9316 in the free list proper. */
9319 /* Construct a freelist object chaining objects off of HEAD. */
9322 /* Add OBJ to the free object list. The former head becomes OBJ's
9323 successor. */
9325 {
9329 }
9331 /* Take an object from the free list, if one is available, or
9332 allocate a new one. Objects taken from the free list should be
9333 regarded as filled with garbage, except for bits that are
9334 configured to be preserved across free and alloc. */
9336 {
9338 {
9343 }
9344 else
9346 }
9347 };
9349 /* Explicitly specialize the interfaces for freelist<tree_node>: we
9350 want to allocate a TREE_LIST using the usual interface, and ensure
9351 TREE_CHAIN remains functional. Alas, we have to duplicate a bit of
9352 build_tree_list logic in reinit, so this could go out of sync. */
9356 {
9358 }
9360 inline tree
9362 {
9364 }
9368 {
9374 #ifdef ENABLE_GC_CHECKING
9377 /* Poison the data, to indicate the data is garbage. */
9380 #endif
9381 /* Let valgrind know the object is free. */
9383 /* But we still want to use the TREE_CODE and TREE_CHAIN parts. */
9387 #ifdef ENABLE_GC_CHECKING
9389 /* Keep TREE_CHAIN functional. */
9391 #else
9393 #endif
9394 }
9398 {
9401 #ifdef ENABLE_GC_CHECKING
9405 #endif
9407 /* Let valgrind know the entire object is available, but
9408 uninitialized. */
9411 #ifdef ENABLE_GC_CHECKING
9413 #else
9415 #endif
9416 }
9418 /* Point to the first object in the TREE_LIST freelist. */
9420 /* Return the/an actual TREE_LIST freelist. */
9423 {
9425 }
9427 /* Point to the first object in the tinst_level freelist. */
9429 /* Return the/an actual tinst_level freelist. */
9432 {
9434 }
9436 /* Point to the first object in the pending_template freelist. */
9438 /* Return the/an actual pending_template freelist. */
9441 {
9443 }
9445 /* Build the TREE_LIST object out of a split list, store it
9446 permanently, and return it. */
9447 tree
9449 {
9458 }
9462 /* Increment OBJ's refcount unless it is already infinite. */
9465 {
9469 }
9471 /* Release storage for OBJ and node, if it's a TREE_LIST. */
9472 void
9474 {
9478 }
9480 /* Decrement OBJ's refcount if not infinite. If it reaches zero, release
9481 OBJ's DECL and OBJ, and start over with the tinst_level object that
9482 used to be referenced by OBJ's NEXT. */
9483 static void
9485 {
9489 {
9493 }
9494 }
9496 /* Modify PTR so that it points to OBJ, adjusting the refcounts of OBJ
9497 and of the former PTR. Omitting the second argument is equivalent
9498 to passing (T*)NULL; this is allowed because passing the
9499 zero-valued integral constant NULL confuses type deduction and/or
9500 overload resolution. */
9502 static void
9504 {
9508 }
9510 static void
9512 {
9522 /* We are called both from instantiate_decl, where we've already had a
9523 tinst_level pushed, and instantiate_template, where we haven't.
9524 Compensate. */
9526 level = !current_tinst_level
9538 else
9547 }
9550 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
9551 ARGLIST. Valid choices for FNS are given in the cp-tree.def
9552 documentation for TEMPLATE_ID_EXPR. */
9554 tree
9556 {
9563 {
9566 }
9569 {
9571 unknown_type_node,
9573 arglist);
9575 }
9578 }
9580 /* Within the scope of a template class S<T>, the name S gets bound
9581 (in build_self_reference) to a TYPE_DECL for the class, not a
9582 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
9583 or one of its enclosing classes, and that type is a template,
9584 return the associated TEMPLATE_DECL. Otherwise, the original
9585 DECL is returned.
9587 Also handle the case when DECL is a TREE_LIST of ambiguous
9588 injected-class-names from different bases. */
9590 tree
9592 {
9596 /* DR 176: A lookup that finds an injected-class-name (10.2
9597 [class.member.lookup]) can result in an ambiguity in certain cases
9598 (for example, if it is found in more than one base class). If all of
9599 the injected-class-names that are found refer to specializations of
9600 the same class template, and if the name is followed by a
9601 template-argument-list, the reference refers to the class template
9602 itself and not a specialization thereof, and is not ambiguous. */
9604 {
9607 {
9613 }
9616 else
9618 }
9624 }
9626 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
9627 parameters, find the desired type.
9629 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
9631 IN_DECL, if non-NULL, is the template declaration we are trying to
9632 instantiate.
9634 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
9635 the class we are looking up.
9637 Issue error and warning messages under control of COMPLAIN.
9639 If the template class is really a local class in a template
9640 function, then the FUNCTION_CONTEXT is the function in which it is
9641 being instantiated.
9643 ??? Note that this function is currently called *twice* for each
9644 template-id: the first time from the parser, while creating the
9645 incomplete type (finish_template_type), and the second type during the
9646 real instantiation (instantiate_template_class). This is surely something
9647 that we want to avoid. It also causes some problems with argument
9648 coercion (see convert_nontype_argument for more information on this). */
9650 static tree
9653 {
9655 tree t;
9658 spec_entry elt;
9659 hashval_t hash;
9662 {
9666 else
9667 {
9674 }
9677 }
9679 {
9682 /* If we are declaring a constructor, say A<T>::A<T>, we will get
9683 an implicit typename for the second A. Deal with it. */
9688 {
9691 }
9692 }
9695 {
9698 }
9700 {
9704 }
9706 {
9709 }
9711 /* Issue an error message if we didn't find a template. */
9713 {
9717 }
9720 /* Make sure it's a user visible template, if it was named by
9721 the user. */
9724 {
9726 {
9730 }
9732 }
9736 /* An alias that just changes the name of a template is equivalent to the
9737 other template, so if any of the arguments are pack expansions, strip
9738 the alias to avoid problems with a pack expansion passed to a non-pack
9739 alias template parameter (DR 1430). */
9744 {
9745 tree parm;
9754 }
9755 else
9756 {
9758 tree gen_tmpl;
9759 tree type_decl;
9767 /* An error occurred while building the template TEMPL, and a
9768 diagnostic has most certainly been emitted for that
9769 already. Let's propagate that error. */
9778 {
9779 /* We've been given an incomplete set of template arguments.
9780 For example, given:
9782 template <class T> struct S1 {
9783 template <class U> struct S2 {};
9784 template <class U> struct S2<U*> {};
9785 };
9787 we will be called with an ARGLIST of `U*', but the
9788 TEMPLATE will be `template <class T> template
9789 <class U> struct S1<T>::S2'. We must fill in the missing
9790 arguments. */
9794 }
9796 /* Now we should have enough arguments. */
9799 /* From here on, we're only interested in the most general
9800 template. */
9802 /* Calculate the BOUND_ARGS. These will be the args that are
9803 actually tsubst'd into the definition to create the
9804 instantiation. */
9806 complain,
9811 /* We were unable to bind the arguments. */
9814 /* In the scope of a template class, explicit references to the
9815 template class refer to the type of the template, not any
9816 instantiation of it. For example, in:
9818 template <class T> class C { void f(C<T>); }
9820 the `C<T>' is just the same as `C'. Outside of the
9821 class, however, such a reference is an instantiation. */
9825 {
9830 }
9832 /* If we already have this specialization, return it. */
9842 /* If the template's constraints are not satisfied,
9843 then we cannot form a valid type.
9845 Note that the check is deferred until after the hash
9846 lookup. This prevents redundant checks on previously
9847 instantiated specializations. */
9851 {
9853 {
9854 auto_diagnostic_group d;
9857 }
9859 }
9863 /* If the deduced arguments are invalid, then the binding
9864 failed. */
9868 complain))
9875 /* This occurs when the user has tried to define a tagged type
9876 in a scope that forbids it. We emitted an error during the
9877 parse. We didn't complete the bail out then, so here we
9878 are. */
9883 {
9886 }
9887 else
9896 /* Create the type. */
9898 {
9899 /* The user referred to a specialization of an alias
9900 template represented by GEN_TMPL.
9902 [temp.alias]/2 says:
9904 When a template-id refers to the specialization of an
9905 alias template, it is equivalent to the associated
9906 type obtained by substitution of its
9907 template-arguments for the template-parameters in the
9908 type-id of the alias template. */
9911 /* Note that the call above (by indirectly calling
9912 register_specialization in tsubst_decl) registers the
9913 TYPE_DECL representing the specialization of the alias
9914 template. So next time someone substitutes ARGLIST for
9915 the template parms into the alias template (GEN_TMPL),
9916 she'll get that TYPE_DECL back. */
9920 }
9922 {
9924 {
9935 }
9936 else
9937 {
9938 /* We don't want to call start_enum for this type, since
9939 the values for the enumeration constants may involve
9940 template parameters. And, no one should be interested
9941 in the enumeration constants for such a type. */
9944 }
9948 }
9950 {
9951 /* Lambda closures are regenerated in tsubst_lambda_expr, not
9952 instantiated here. */
9960 /* A local class. Make sure the decl gets registered properly. */
9967 /* This instantiation is another name for the primary
9968 template type. Set the TYPE_CANONICAL field
9969 appropriately. */
9972 /* Some of the template arguments require structural
9973 equality testing, so this template class requires
9974 structural equality testing. */
9976 }
9977 else
9980 /* If we called start_enum or pushtag above, this information
9981 will already be set up. */
9984 {
9991 }
9994 {
10000 {
10003 }
10004 }
10008 {
10012 {
10013 tree attributes
10021 }
10022 }
10024 /* Let's consider the explicit specialization of a member
10025 of a class template specialization that is implicitly instantiated,
10026 e.g.:
10027 template<class T>
10028 struct S
10029 {
10030 template<class U> struct M {}; //#0
10031 };
10033 template<>
10034 template<>
10035 struct S<int>::M<char> //#1
10036 {
10037 int i;
10038 };
10039 [temp.expl.spec]/4 says this is valid.
10041 In this case, when we write:
10042 S<int>::M<char> m;
10044 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
10045 the one of #0.
10047 When we encounter #1, we want to store the partial instantiation
10048 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
10050 For all cases other than this "explicit specialization of member of a
10051 class template", we just want to store the most general template into
10052 the CLASSTYPE_TI_TEMPLATE of M.
10054 This case of "explicit specialization of member of a class template"
10055 only happens when:
10056 1/ the enclosing class is an instantiation of, and therefore not
10057 the same as, the context of the most general template, and
10058 2/ we aren't looking at the partial instantiation itself, i.e.
10059 the innermost arguments are not the same as the innermost parms of
10060 the most general template.
10062 So it's only when 1/ and 2/ happens that we want to use the partial
10063 instantiation of the member template in lieu of its most general
10064 template. */
10068 /* the enclosing class must be an instantiation... */
10071 {
10075 tree partial_inst_args =
10082 use_partial_inst_tmpl =
10083 /*...and we must not be looking at the partial instantiation
10084 itself. */
10086 partial_inst_args);
10087 }
10090 /* This case is easy; there are no member templates involved. */
10092 else
10093 {
10094 /* This is a full instantiation of a member template. Find
10095 the partial instantiation of which this is an instance. */
10097 /* Temporarily reduce by one the number of levels in the ARGLIST
10098 so as to avoid comparing the last set of arguments. */
10102 /* FOUND is either a proper class type, or an alias
10103 template specialization. In the later case, it's a
10104 TYPE_DECL, resulting from the substituting of arguments
10105 for parameters in the TYPE_DECL of the alias template
10106 done earlier. So be careful while getting the template
10107 of FOUND. */
10109 ? found
10116 {
10117 /* If this partial instantiation is specialized, we want to
10118 use it for hash table lookup. */
10122 }
10123 }
10125 /* Build template info for the new specialization. */
10127 {
10128 /* This is constructed during instantiation of the alias
10129 decl. But for member templates of template classes, that
10130 is not correct as we need to refer to the partially
10131 instantiated template, not the most general template.
10132 The incorrect knowledge will not have escaped this
10133 instantiation process, so we're good just updating the
10134 template_info we made then. */
10138 {
10141 }
10142 }
10143 else
10153 /* Note this use of the partial instantiation so we can check it
10154 later in maybe_process_partial_specialization. */
10161 /* Now that the type has been registered on the instantiations
10162 list, we set up the enumerators. Because the enumeration
10163 constants may involve the enumeration type itself, we make
10164 sure to register the type first, and then create the
10165 constants. That way, doing tsubst_expr for the enumeration
10166 constants won't result in recursive calls here; we'll find
10167 the instantiation and exit above. */
10171 /* If the type makes use of template parameters, the
10172 code that generates debugging information will crash. */
10175 /* Possibly limit visibility based on template args. */
10182 }
10183 }
10185 /* Wrapper for lookup_template_class_1. */
10187 tree
10190 {
10191 tree ret;
10197 }
10199 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
10201 tree
10203 {
10207 /* The type of the expression is NULL_TREE since the template-id could refer
10208 to an explicit or partial specialization. */
10210 }
10212 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
10214 tree
10216 {
10232 {
10234 {
10235 auto_diagnostic_group d;
10238 }
10240 }
10243 }
10245 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
10246 TARGS template args, and instantiate it if it's not dependent. */
10248 tree
10250 tsubst_flags_t complain)
10251 {
10254 {
10257 }
10260 }
10262 /* If the set of template parameters PARMS contains a template parameter
10263 at the given LEVEL and INDEX, then return this parameter. Otherwise
10264 return NULL_TREE. */
10266 static tree
10268 {
10277 /* As in template_parm_to_arg. */
10280 else
10285 }
10287 /* Return the template parameter from PARMS that positionally corresponds
10288 to the template parameter PARM, or else return NULL_TREE. */
10290 static tree
10292 {
10296 }
10298 \f
10299 struct pair_fn_data
10300 {
10301 tree_fn_t fn;
10302 tree_fn_t any_fn;
10304 /* True when we should also visit template parameters that occur in
10305 non-deduced contexts. */
10308 };
10310 /* Called from for_each_template_parm via walk_tree. */
10312 static tree
10314 {
10321 #define WALK_SUBTREE(NODE) \
10322 do \
10323 { \
10324 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
10325 pfd->include_nondeduced_p, \
10326 pfd->any_fn); \
10327 if (result) goto out; \
10328 } \
10329 while (0)
10339 {
10343 /* Fall through. */
10349 else
10359 /* Since we're not going to walk subtrees, we have to do this
10360 explicitly here. */
10362 /* Fall through. */
10365 /* Check the return type. */
10368 /* Check the parameter types. Since default arguments are not
10369 instantiated until they are needed, the TYPE_ARG_TYPES may
10370 contain expressions that involve template parameters. But,
10371 no-one should be looking at them yet. And, once they're
10372 instantiated, they don't contain template parameters, so
10373 there's no point in looking at them then, either. */
10374 {
10375 tree parm;
10380 /* Since we've already handled the TYPE_ARG_TYPES, we don't
10381 want walk_tree walking into them itself. */
10383 }
10386 {
10390 }
10409 /* Fall through. */
10421 /* Record template parameters such as `T' inside `TT<T>'. */
10423 /* Fall through. */
10435 /* A template template parameter is encountered. */
10439 /* Already substituted template template parameter */
10444 /* A template-id in a TYPENAME_TYPE might be a deduced context after
10445 partial instantiation. */
10458 /* If there's no type, then this thing must be some expression
10459 involving template parameters. */
10485 {
10489 /* Recursively walk the type of each constraint variable. */
10492 {
10495 }
10496 }
10501 }
10503 #undef WALK_SUBTREE
10505 /* We didn't find any template parameters we liked. */
10506 out:
10508 }
10510 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
10511 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
10512 call FN with the parameter and the DATA.
10513 If FN returns nonzero, the iteration is terminated, and
10514 for_each_template_parm returns 1. Otherwise, the iteration
10515 continues. If FN never returns a nonzero value, the value
10516 returned by for_each_template_parm is 0. If FN is NULL, it is
10517 considered to be the function which always returns 1.
10519 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
10520 parameters that occur in non-deduced contexts. When false, only
10521 visits those template parameters that can be deduced. */
10523 static tree
10527 tree_fn_t any_fn)
10528 {
10530 tree result;
10532 /* Set up. */
10538 /* Walk the tree. (Conceptually, we would like to walk without
10539 duplicates, but for_each_template_parm_r recursively calls
10540 for_each_template_parm, so we would need to reorganize a fair
10541 bit to use walk_tree_without_duplicates, so we keep our own
10542 visited list.) */
10545 else
10548 for_each_template_parm_r,
10552 /* Clean up. */
10554 {
10557 }
10560 }
10562 struct find_template_parameter_info
10563 {
10568 {}
10572 tree parm_list;
10573 tree ctx_parms;
10575 };
10577 /* Appends the declaration of T to the list in DATA. */
10579 static int
10581 {
10584 /* Template parameters declared within the expression are not part of
10585 the parameter mapping. For example, in this concept:
10587 template<typename T>
10588 concept C = requires { <expr> } -> same_as<int>;
10590 the return specifier same_as<int> declares a new decltype parameter
10591 that must not be part of the parameter mapping. The same is true
10592 for generic lambda parameters, lambda template parameters, etc. */
10600 /* We want the underlying TEMPLATE_TEMPLATE_PARM, not the
10601 BOUND_TEMPLATE_TEMPLATE_PARM itself. */
10604 /* This template parameter might be an argument to a cached dependent
10605 specalization that was formed earlier inside some other template, in
10606 which case the parameter is not among the ones that are in-scope.
10607 Look in CTX_PARMS to find the corresponding in-scope template
10608 parameter, and use it instead. */
10612 /* Arguments like const T yield parameters like const T. This means that
10613 a template-id like X<T, const T> would yield two distinct parameters:
10614 T and const T. Adjust types to their unqualified versions. */
10620 /* Verify the parameter we found has a valid index. */
10622 {
10628 }
10631 }
10633 /* Ensure that we recursively examine certain terms that are not normally
10634 visited in for_each_template_parm_r. */
10636 static int
10638 {
10641 #define WALK_SUBTREE(NODE) \
10642 do \
10643 { \
10644 for_each_template_parm (NODE, keep_template_parm, data, \
10645 &ftpi->visited, true, \
10646 any_template_parm_r); \
10647 } \
10648 while (0)
10650 /* A mention of a member alias/typedef is a use of all of its template
10651 arguments, including those from the enclosing class, so we don't use
10652 alias_template_specialization_p here. */
10658 {
10660 /* Type constraints of a placeholder type may contain parameters. */
10667 /* Search through references to variable templates. */
10674 /* A parameter or constraint variable may also depend on a template
10675 parameter without explicitly naming it. */
10680 {
10681 /* If T is a member template that shares template parameters with
10682 ctx_parms, we need to mark all those parameters for mapping. */
10695 {
10700 }
10701 }
10705 {
10706 /* Look in the parms and body. */
10710 }
10715 /* The conversion-type-id of a conversion operator may be dependent. */
10721 }
10723 /* Keep walking. */
10725 }
10727 /* Returns a list of unique template parameters found within T, where CTX_PARMS
10728 are the template parameters in scope. */
10730 tree
10732 {
10740 }
10742 /* Returns true if T depends on any template parameter. */
10744 int
10746 {
10767 else
10773 }
10775 /* Returns true iff current_function_decl is an incompletely instantiated
10776 template. Useful instead of processing_template_decl because the latter
10777 is set to 0 during instantiate_non_dependent_expr. */
10779 bool
10781 {
10790 }
10792 /* Returns true if T depends on any template parameter with level LEVEL. */
10794 bool
10796 {
10799 }
10801 /* Returns true if the signature of DECL depends on any template parameter from
10802 its enclosing class. */
10804 bool
10806 {
10816 template_parm_outer_level,
10826 }
10828 /* Returns TRUE iff INST is an instantiation we don't need to do in an
10829 ill-formed translation unit, i.e. a variable or function that isn't
10830 usable in a constant expression. */
10834 {
10839 }
10841 /* Returns TRUE iff we should refuse to instantiate DECL because it's
10842 neglectable and instantiated from within an erroneous instantiation. */
10844 static bool
10846 {
10857 }
10865 /* We're starting to instantiate D; record the template instantiation context
10866 at LOC for diagnostics and to restore it later. */
10868 bool
10870 {
10874 {
10875 /* Tell error.c not to try to instantiate any templates. */
10878 "template instantiation depth exceeds maximum of %d"
10880 max_tinst_depth);
10882 }
10884 /* If the current instantiation caused problems, don't let it instantiate
10885 anything else. Do allow deduction substitution and decls usable in
10886 constant expressions. */
10888 {
10889 /* Avoid no_linkage_errors and unused function warnings for this
10890 decl. */
10893 }
10895 /* When not -quiet, dump template instantiations other than functions, since
10896 announce_function will take care of those. */
10917 }
10919 /* We're starting substitution of TMPL<ARGS>; record the template
10920 substitution context for diagnostics and to restore it later. */
10922 bool
10924 {
10926 }
10928 /* We're starting to instantiate D; record INPUT_LOCATION and the
10929 template instantiation context for diagnostics and to restore it
10930 later. */
10932 bool
10934 {
10936 }
10938 /* Likewise, but record LOC as the program location. */
10940 bool
10942 {
10945 }
10947 /* We're done instantiating this template; return to the instantiation
10948 context. */
10950 void
10952 {
10953 /* Restore the filename and line number stashed away when we started
10954 this instantiation. */
10958 }
10960 /* We're instantiating a deferred template; restore the template
10961 instantiation context in which the instantiation was requested, which
10962 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
10964 static tree
10966 {
10978 }
10980 /* Returns the TINST_LEVEL which gives the original instantiation
10981 context. */
10985 {
10991 }
10993 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
10994 vector of template arguments, as for tsubst.
10996 Returns an appropriate tsubst'd friend declaration. */
10998 static tree
11000 {
11001 tree new_friend;
11006 /* This was a friend declared with an explicit template
11007 argument list, e.g.:
11009 friend void f<>(T);
11011 to indicate that f was a template instantiation, not a new
11012 function declaration. Now, we have to figure out what
11013 instantiation of what template. */
11014 {
11016 tree new_args;
11017 tree tmpl;
11020 /* Friend functions are looked up in the containing namespace scope.
11021 We must enter that scope, to avoid finding member functions of the
11022 current class with same name. */
11037 tsk_none);
11039 }
11045 /* The NEW_FRIEND will look like an instantiation, to the
11046 compiler, but is not an instantiation from the point of view of
11047 the language. For example, we might have had:
11049 template <class T> struct S {
11050 template <class U> friend void f(T, U);
11051 };
11053 Then, in S<int>, template <class U> void f(int, U) is not an
11054 instantiation of anything. */
11058 {
11063 /* Substitute TEMPLATE_PARMS_CONSTRAINTS so that parameter levels will
11064 match in decls_match. */
11069 }
11071 /* The mangled name for the NEW_FRIEND is incorrect. The function
11072 is not a template instantiation and should not be mangled like
11073 one. Therefore, we forget the mangling here; we'll recompute it
11074 later if we need it. */
11076 {
11079 }
11082 {
11083 tree old_decl;
11084 tree ns;
11086 /* We must save some information from NEW_FRIEND before calling
11087 duplicate decls since that function will free NEW_FRIEND if
11088 possible. */
11098 {
11099 /* This declaration is a `primary' template. */
11104 }
11106 /* Inside pushdecl_namespace_level, we will push into the
11107 current namespace. However, the friend function should go
11108 into the namespace of the template. */
11118 {
11119 /* This new friend declaration matched an existing
11120 declaration. For example, given:
11122 template <class T> void f(T);
11123 template <class U> class C {
11124 template <class T> friend void f(T) {}
11125 };
11127 the friend declaration actually provides the definition
11128 of `f', once C has been instantiated for some type. So,
11129 old_decl will be the out-of-class template declaration,
11130 while new_friend is the in-class definition.
11132 But, if `f' was called before this point, the
11133 instantiation of `f' will have DECL_TI_ARGS corresponding
11134 to `T' but not to `U', references to which might appear
11135 in the definition of `f'. Previously, the most general
11136 template for an instantiation of `f' was the out-of-class
11137 version; now it is the in-class version. Therefore, we
11138 run through all specialization of `f', adding to their
11139 DECL_TI_ARGS appropriately. In particular, they need a
11140 new set of outer arguments, corresponding to the
11141 arguments for this class instantiation.
11143 The same situation can arise with something like this:
11145 friend void f(int);
11146 template <class T> class C {
11147 friend void f(T) {}
11148 };
11150 when `C<int>' is instantiated. Now, `f(int)' is defined
11151 in the class. */
11154 /* On the other hand, if the in-class declaration does
11155 *not* provide a definition, then we don't want to alter
11156 existing definitions. We can just leave everything
11157 alone. */
11158 ;
11159 else
11160 {
11164 /* Overwrite whatever template info was there before, if
11165 any, with the new template information pertaining to
11166 the declaration. */
11170 {
11171 /* We should have called reregister_specialization in
11172 duplicate_decls. */
11177 /* Instantiate it if the global has already been used. */
11181 }
11182 else
11183 {
11184 tree t;
11186 /* Indicate that the old function template is a partial
11187 instantiation. */
11195 /* Reassign any specializations already in the hash table
11196 to the new more general template, and add the
11197 additional template args. */
11201 {
11203 spec_entry elt;
11215 register_specialization
11218 }
11220 }
11221 }
11223 /* The information from NEW_FRIEND has been merged into OLD_DECL
11224 by duplicate_decls. */
11226 }
11227 }
11228 else
11229 {
11233 /* In the code
11234 template <class T> class C {
11235 template <class U> friend void C1<U>::f (); // case 1
11236 friend void C2<T>::f (); // case 2
11237 };
11238 we only need to make sure CONTEXT is a complete type for
11239 case 2. To distinguish between the two cases, we note that
11240 CONTEXT of case 1 remains dependent type after tsubst while
11241 this isn't true for case 2. */
11251 {
11253 /* do_friend adds the TEMPLATE_DECL for any member friend
11254 template even if it isn't a member template, i.e.
11255 template <class T> friend A<T>::f();
11256 Look through it in that case. */
11260 /* Check to see that the declaration is really present, and,
11261 possibly obtain an improved declaration. */
11266 }
11267 }
11270 }
11272 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
11273 template arguments, as for tsubst.
11275 Returns an appropriate tsubst'd friend type or error_mark_node on
11276 failure. */
11278 static tree
11280 {
11281 tree tmpl;
11284 {
11287 }
11292 else
11293 {
11296 }
11302 {
11303 /* The friend template has already been declared. Just
11304 check to see that the declarations match, and install any new
11305 default parameters. We must tsubst the default parameters,
11306 of course. We only need the innermost template parameters
11307 because that is all that redeclare_class_template will look
11308 at. */
11311 {
11319 }
11320 }
11321 else
11322 {
11323 /* The friend template has not already been declared. In this
11324 case, the instantiation of the template class will cause the
11325 injection of this template into the namespace scope. */
11329 {
11330 /* The new TMPL is not an instantiation of anything, so we
11331 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
11332 for the new type because that is supposed to be the
11333 corresponding template decl, i.e., TMPL. */
11340 /* Substitute into and set the constraints on the new declaration. */
11342 {
11348 }
11350 /* Inject this template into the enclosing namspace scope. */
11352 }
11353 }
11357 else
11361 }
11363 /* Returns zero if TYPE cannot be completed later due to circularity.
11364 Otherwise returns one. */
11366 static int
11368 {
11378 else
11380 }
11385 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
11386 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
11388 static tree
11391 {
11400 {
11407 clauses
11411 else
11413 }
11417 {
11419 tree varid
11430 {
11434 {
11436 {
11444 }
11445 else
11446 {
11450 {
11451 bool allow_string
11463 {
11464 location_t loc
11466 match_loc);
11472 "integer expression or string "
11474 else
11478 }
11481 {
11482 location_t loc
11484 match_loc);
11488 }
11490 }
11491 }
11492 }
11493 }
11495 }
11496 /* If the first attribute argument is an identifier, don't
11497 pass it through tsubst. Attributes like mode, format,
11498 cleanup and several target specific attributes expect it
11499 unmodified. */
11501 {
11502 tree chain
11507 }
11509 {
11510 /* An attribute pack expansion. */
11519 {
11523 }
11525 }
11526 else
11533 }
11535 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
11536 unchanged or a new TREE_LIST chain. */
11538 static tree
11541 {
11546 {
11550 }
11554 {
11557 {
11560 {
11566 }
11567 }
11569 }
11572 }
11574 /* Apply any attributes which had to be deferred until instantiation
11575 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
11576 ARGS, COMPLAIN, IN_DECL are as tsubst. */
11578 static void
11581 {
11583 tree t;
11590 {
11594 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
11595 to our attributes parameter. */
11597 }
11598 else
11599 {
11601 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
11602 lookup_template_class_1, and should be preserved. */
11606 }
11610 {
11614 }
11618 {
11623 {
11626 {
11632 }
11633 else
11635 }
11638 }
11639 }
11641 /* The template TMPL is being instantiated with the template arguments TARGS.
11642 Perform the access checks that we deferred when parsing the template. */
11644 static void
11646 {
11656 {
11664 /* Make access check error messages point to the location
11665 of the use of the typedef. */
11669 }
11670 }
11672 static tree
11674 {
11676 tree typedecl;
11677 tree pbinfo;
11678 tree base_list;
11680 tree fn_context;
11689 /* Figure out which template is being instantiated. */
11693 /* Mark the type as in the process of being defined. */
11696 /* We may be in the middle of deferred access check. Disable
11697 it now. */
11700 /* Determine what specialization of the original template to
11701 instantiate. */
11706 {
11707 /* This TYPE is actually an instantiation of a partial
11708 specialization. We replace the innermost set of ARGS with
11709 the arguments appropriate for substitution. For example,
11710 given:
11712 template <class T> struct S {};
11713 template <class T> struct S<T*> {};
11715 and supposing that we are instantiating S<int*>, ARGS will
11716 presently be {int*} -- but we need {int}. */
11719 }
11720 else
11721 {
11724 }
11726 /* If the template we're instantiating is incomplete, then clearly
11727 there's nothing we can do. */
11729 {
11730 /* We can try again later. */
11733 }
11735 /* If we've recursively instantiated too many templates, stop. */
11743 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
11748 else
11749 {
11752 }
11753 /* Use #pragma pack from the template context. */
11759 /* Set the input location to the most specialized template definition.
11760 This is needed if tsubsting causes an error. */
11772 {
11775 /* Adjust visibility for template arguments. */
11777 }
11783 /* We should never instantiate a nested class before its enclosing
11784 class; we need to look up the nested class by name before we can
11785 instantiate it, and that lookup should instantiate the enclosing
11786 class. */
11792 {
11793 tree pbase_binfo;
11794 tree pushed_scope;
11797 /* We must enter the scope containing the type, as that is where
11798 the accessibility of types named in dependent bases are
11799 looked up from. */
11802 /* Substitute into each of the bases to determine the actual
11803 basetypes. */
11805 {
11806 tree base;
11812 {
11813 expanded_bases =
11820 }
11823 {
11825 /* Extract the already-expanded base class. */
11827 else
11828 /* Substitute to figure out the base class. */
11830 NULL_TREE);
11838 }
11839 }
11841 /* The list is now in reverse order; correct that. */
11846 }
11847 /* Now call xref_basetypes to set up all the base-class
11848 information. */
11856 /* Now that our base classes are set up, enter the scope of the
11857 class, so that name lookups into base classes, etc. will work
11858 correctly. This is precisely analogous to what we do in
11859 begin_class_definition when defining an ordinary non-template
11860 class, except we also need to push the enclosing classes. */
11863 /* Now members are processed in the order of declaration. */
11866 {
11870 {
11872 {
11874 /* A closure type for a lambda in an NSDMI or default argument.
11875 Ignore it; it will be regenerated when needed. */
11882 /* If the member is a class template, then -- even after
11883 substitution -- there may be dependent types in the
11884 template argument list for the class. We increment
11885 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
11886 that function will assume that no types are dependent
11887 when outside of a template. */
11897 {
11901 /* Unfortunately, lookup_template_class sets
11902 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
11903 instantiation (i.e., for the type of a member
11904 template class nested within a template class.)
11905 This behavior is required for
11906 maybe_process_partial_specialization to work
11907 correctly, but is not accurate in this case;
11908 the TAG is not an instantiation of anything.
11909 (The corresponding TEMPLATE_DECL is an
11910 instantiation, but the TYPE is not.) */
11913 /* Now, we call pushtag to put this NEWTAG into the scope of
11914 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
11915 pushtag calling push_template_decl. We don't have to do
11916 this for enums because it will already have been done in
11917 tsubst_enum. */
11921 }
11922 }
11924 {
11925 tree r;
11934 /* Instantiate members marked with attribute used. */
11940 }
11943 /* A closure type for a lambda in an NSDMI or default argument.
11945 else
11946 {
11947 /* Build new TYPE_FIELDS. */
11952 {
11953 tree r;
11958 /* The file and line for this declaration, to
11959 assist in error message reporting. Since we
11960 called push_tinst_level above, we don't need to
11961 restore these. */
11971 {
11972 /* A capture pack became multiple fields. */
11975 }
11978 {
11982 {
11983 /* In [temp.inst]:
11985 [t]he initialization (and any associated
11986 side-effects) of a static data member does
11987 not occur unless the static data member is
11988 itself used in a way that requires the
11989 definition of the static data member to
11990 exist.
11992 Therefore, we do not substitute into the
11993 initialized for the static data member here. */
11994 finish_static_data_member_decl
12000 /* Instantiate members marked with attribute used. */
12003 }
12005 {
12006 /* Determine whether R has a valid type and can be
12007 completed later. If R is invalid, then its type
12008 is replaced by error_mark_node. */
12014 {
12015 /* If R's type couldn't be completed and
12016 it isn't a flexible array member (whose
12017 type is incomplete by definition) give
12018 an error. */
12021 }
12026 {
12029 }
12033 }
12035 /* If it is a TYPE_DECL for a class-scoped
12036 ENUMERAL_TYPE, such a thing will already have
12037 been added to the field list by tsubst_enum
12038 in finish_member_declaration case above. */
12042 {
12045 }
12046 }
12047 }
12048 }
12049 }
12050 else
12051 {
12054 {
12055 /* Build new CLASSTYPE_FRIEND_CLASSES. */
12061 {
12062 /* template <class T> friend class C; */
12065 }
12067 {
12068 /* template <class T> friend class C::D; */
12074 }
12077 {
12078 /* This could be either
12080 friend class T::C;
12082 when dependent_type_p is false or
12084 template <class U> friend class T::C;
12086 otherwise. */
12087 /* Bump processing_template_decl in case this is something like
12088 template <class T> friend struct A<T>::B. */
12095 }
12097 /* friend class C<T>; */
12101 /* Otherwise it's
12103 friend class C;
12105 where C is already declared or
12107 friend class C<int>;
12109 We don't have to do anything in these cases. */
12112 /* Trick make_friend_class into realizing that the friend
12113 we're adding is a template, not an ordinary class. It's
12114 important that we use make_friend_class since it will
12115 perform some error-checking and output cross-reference
12116 information. */
12124 }
12125 else
12126 {
12127 /* Build new DECL_FRIENDLIST. */
12128 tree r;
12130 /* The file and line for this declaration, to
12131 assist in error message reporting. Since we
12132 called push_tinst_level above, we don't need to
12133 restore these. */
12137 {
12140 }
12145 {
12148 }
12149 }
12150 }
12151 }
12154 {
12155 /* Restore these before substituting into the lambda capture
12156 initializers. */
12159 }
12161 /* Set the file and line number information to whatever is given for
12162 the class itself. This puts error messages involving generated
12163 implicit functions at a predictable point, and the same point
12164 that would be used for non-template classes. */
12171 /* We don't instantiate default arguments for member functions. 14.7.1:
12173 The implicit instantiation of a class template specialization causes
12174 the implicit instantiation of the declarations, but not of the
12175 definitions or default arguments, of the class member functions,
12176 member classes, static data members and member templates.... */
12186 /* The vtable for a template class can be emitted in any translation
12187 unit in which the class is instantiated. When there is no key
12188 method, however, finish_struct_1 will already have added TYPE to
12189 the keyed_classes. */
12194 }
12196 /* Wrapper for instantiate_class_template_1. */
12198 tree
12200 {
12201 tree ret;
12206 }
12208 tree
12210 {
12211 tree r;
12217 else
12218 {
12225 }
12228 }
12230 /* Given a function parameter pack TMPL_PARM and some function parameters
12231 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
12232 and set *SPEC_P to point at the next point in the list. */
12234 tree
12236 {
12237 /* Collect all of the extra "packed" parameters into an
12238 argument pack. */
12239 tree parmvec;
12249 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
12253 {
12258 }
12260 /* Build the argument packs. */
12265 }
12267 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
12268 NONTYPE_ARGUMENT_PACK. */
12270 static tree
12272 {
12274 }
12276 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
12277 pack expansion with no extra args, 2 if it has extra args, or 0
12278 if it is not a pack expansion. */
12280 static int
12282 {
12284 /* We're being called before this happens in tsubst_pack_expansion. */
12291 /* A decl pack is itself an expansion. */
12298 }
12301 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
12303 static tree
12305 {
12312 }
12314 /* This is a subroutine of tsubst_pack_expansion.
12316 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
12317 mechanism to store the (non complete list of) arguments of the
12318 substitution and return a non substituted pack expansion, in order
12319 to wait for when we have enough arguments to really perform the
12320 substitution. */
12322 static bool
12326 {
12327 /* If one pack has an expansion and another pack has a normal
12328 argument or if one pack has an empty argument and an another
12329 one hasn't then tsubst_pack_expansion cannot perform the
12330 substitution and need to fall back on the
12331 PACK_EXPANSION_EXTRA mechanism. */
12335 {
12336 /* If all the actual packs are pack expansions, we can still
12337 subsitute directly. */
12339 {
12349 }
12351 }
12355 {
12358 parm_pack;
12360 {
12365 /* We can't substitute a pack expansion with extra args into
12366 our pattern. */
12370 else
12372 }
12376 }
12378 }
12380 /* [temp.variadic]/6 says that:
12382 The instantiation of a pack expansion [...]
12383 produces a list E1,E2, ..., En, where N is the number of elements
12384 in the pack expansion parameters.
12386 This subroutine of tsubst_pack_expansion produces one of these Ei.
12388 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
12389 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
12390 PATTERN, and each TREE_VALUE is its corresponding argument pack.
12391 INDEX is the index 'i' of the element Ei to produce. ARGS,
12392 COMPLAIN, and IN_DECL are the same parameters as for the
12393 tsubst_pack_expansion function.
12395 The function returns the resulting Ei upon successful completion,
12396 or error_mark_node.
12398 Note that this function possibly modifies the ARGS parameter, so
12399 it's the responsibility of the caller to restore it. */
12401 static tree
12403 tree parm_packs,
12405 tree args /* This parm gets
12407 tsubst_flags_t complain,
12408 tree in_decl)
12409 {
12410 tree t;
12413 /* For each parameter pack, change the substitution of the parameter
12414 pack to the ith argument in its argument pack, then expand the
12415 pattern. */
12417 {
12422 ith_elem_is_expansion |=
12425 /* Select the Ith argument from the pack. */
12429 {
12431 {
12436 }
12437 else
12439 }
12440 else
12441 {
12446 {
12448 /* Update the corresponding argument. */
12450 }
12451 else
12452 /* Re-use the ARGUMENT_PACK_SELECT. */
12454 }
12456 }
12458 /* Substitute into the PATTERN with the (possibly altered)
12459 arguments. */
12461 /* Expanding a fixed parameter pack from
12462 coerce_template_parameter_pack. */
12469 else
12472 /* If the Ith argument pack element is a pack expansion, then
12473 the Ith element resulting from the substituting is going to
12474 be a pack expansion as well. */
12479 }
12481 /* When the unexpanded parameter pack in a fold expression expands to an empty
12482 sequence, the value of the expression is as follows; the program is
12483 ill-formed if the operator is not listed in this table.
12485 && true
12486 || false
12487 , void() */
12489 tree
12491 {
12495 {
12504 }
12510 }
12512 /* Given a fold-expression T and a current LEFT and RIGHT operand,
12513 form an expression that combines the two terms using the
12514 operator of T. */
12516 static tree
12518 {
12522 // Handle compound assignment operators.
12528 {
12536 complain);
12537 }
12538 }
12540 /* Substitute ARGS into the pack of a fold expression T. */
12544 {
12546 }
12548 /* Substitute ARGS into the pack of a fold expression T. */
12552 {
12554 }
12556 /* Expand a PACK of arguments into a grouped as left fold.
12557 Given a pack containing elements A0, A1, ..., An and an
12558 operator @, this builds the expression:
12560 ((A0 @ A1) @ A2) ... @ An
12562 Note that PACK must not be empty.
12564 The operator is defined by the original fold expression T. */
12566 static tree
12568 {
12571 {
12574 }
12576 }
12578 /* Substitute into a unary left fold expression. */
12580 static tree
12582 tree in_decl)
12583 {
12588 {
12592 }
12595 else
12597 }
12599 /* Substitute into a binary left fold expression.
12601 Do ths by building a single (non-empty) vector of argumnts and
12602 building the expression from those elements. */
12604 static tree
12606 tree in_decl)
12607 {
12616 {
12621 }
12629 }
12631 /* Expand a PACK of arguments into a grouped as right fold.
12632 Given a pack containing elementns A0, A1, ..., and an
12633 operator @, this builds the expression:
12635 A0@ ... (An-2 @ (An-1 @ An))
12637 Note that PACK must not be empty.
12639 The operator is defined by the original fold expression T. */
12641 tree
12643 {
12644 // Build the expression.
12648 {
12651 }
12653 }
12655 /* Substitute into a unary right fold expression. */
12657 static tree
12659 tree in_decl)
12660 {
12665 {
12669 }
12672 else
12674 }
12676 /* Substitute into a binary right fold expression.
12678 Do ths by building a single (non-empty) vector of arguments and
12679 building the expression from those elements. */
12681 static tree
12683 tree in_decl)
12684 {
12693 {
12698 }
12707 }
12709 /* Walk through the pattern of a pack expansion, adding everything in
12710 local_specializations to a list. */
12712 class el_data
12713 {
12716 tree extra;
12717 tsubst_flags_t complain;
12721 };
12722 static tree
12724 {
12730 /* Remember local typedefs (85214). */
12736 {
12738 /* Don't mess with variables declared within the pattern. */
12741 {
12742 /* Maybe pull out the PARM_DECL for a partial instantiation. */
12745 {
12751 }
12753 {
12754 /* Handle lambda capture here, since we aren't doing any
12755 substitution now, and so tsubst_copy won't call
12756 process_outer_var_ref. */
12760 {
12766 {
12767 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
12768 proxies. */
12770 {
12775 }
12777 }
12778 }
12779 }
12780 }
12784 }
12786 }
12787 static tree
12789 {
12793 }
12795 /* Extract any uses of local_specializations from PATTERN and add them to ARGS
12796 for use in PACK_EXPANSION_EXTRA_ARGS. */
12798 tree
12800 {
12806 }
12808 /* Apply any local specializations from PACK_EXPANSION_EXTRA_ARGS and add the
12809 normal template args to ARGS. */
12811 tree
12813 {
12815 {
12817 {
12818 /* The partial instantiation involved local declarations collected in
12819 extract_local_specs; map from the general template to our local
12820 context. */
12826 /* else inst is already a full instantiation of the pack. */
12828 }
12831 }
12832 #if 1
12833 /* I think we should always be able to substitute dependent args into the
12834 pattern. If that turns out to be incorrect in some cases, enable the
12835 alternate code (and add complain/in_decl parms to this function). */
12837 #else
12839 {
12843 }
12844 else
12845 #endif
12848 }
12850 /* Substitute ARGS into T, which is an pack expansion
12851 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
12852 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
12853 (if only a partial substitution could be performed) or
12854 ERROR_MARK_NODE if there was an error. */
12855 tree
12857 tree in_decl)
12858 {
12859 tree pattern;
12863 tree result;
12870 /* Add in any args remembered from an earlier partial instantiation. */
12875 /* Determine the argument packs that will instantiate the parameter
12876 packs used in the expansion expression. While we're at it,
12877 compute the number of arguments to be expanded and make sure it
12878 is consistent. */
12881 {
12888 {
12894 complain);
12895 else
12899 }
12901 {
12903 {
12906 parm_pack);
12908 }
12911 }
12913 {
12914 /* We know we have correct local_specializations if this
12915 expansion is at function scope, or if we're dealing with a
12916 local parameter in a requires expression; for the latter,
12917 tsubst_requires_expr set it up appropriately. */
12920 else
12921 /* We can't rely on local_specializations for a parameter
12922 name used later in a function declaration (such as in a
12923 late-specified return type). Even if it exists, it might
12924 have the wrong value for a recursive call. */
12928 {
12929 /* This parameter pack was used in an unevaluated context. Just
12930 make a dummy decl, since it's only used for its type. */
12935 /* Partial instantiation of the parm_pack, we can't build
12936 up an argument pack yet. */
12938 else
12940 }
12942 /* This argument pack isn't fully instantiated yet. */
12944 }
12946 {
12950 }
12951 else
12952 {
12961 }
12968 /* This can only happen if we forget to expand an argument
12969 pack somewhere else. Just return an error, silently. */
12970 {
12974 }
12977 {
12981 /* Don't bother trying to do a partial substitution with
12982 incomplete packs; we'll try again after deduction. */
12989 {
12994 pattern);
12995 else
12997 pattern);
12999 }
13001 /* Keep track of the parameter packs and their corresponding
13002 argument packs. */
13005 }
13006 else
13007 {
13008 /* We can't substitute for this parameter pack. We use a flag as
13009 well as the missing_level counter because function parameter
13010 packs don't have a level. */
13013 }
13014 }
13016 /* If the expansion is just T..., return the matching argument pack, unless
13017 we need to call convert_from_reference on all the elements. This is an
13018 important optimization; see c++/68422. */
13021 {
13024 /* If the argument pack is a single pack expansion, pull it out. */
13029 /* Types need no adjustment, nor does sizeof..., and if we still have
13030 some pack expansion args we won't do anything yet. */
13035 /* Also optimize expression pack expansions if we can tell that the
13036 elements won't have reference type. */
13042 /* Otherwise use the normal path so we get convert_from_reference. */
13043 }
13045 /* We cannot expand this expansion expression, because we don't have
13046 all of the argument packs we need. */
13048 {
13049 /* We got some full packs, but we can't substitute them in until we
13050 have values for all the packs. So remember these until then. */
13056 }
13058 /* If NEED_LOCAL_SPECIALIZATIONS then we're in a late-specified return
13059 type, so create our own local specializations map; the current map is
13060 either NULL or (in the case of recursive unification) might have
13061 bindings that we don't want to use or alter. */
13066 {
13067 /* There were no real arguments, we're just replacing a parameter
13068 pack with another version of itself. Substitute into the
13069 pattern and return a PACK_EXPANSION_*. The caller will need to
13070 deal with that. */
13074 else
13078 }
13082 /* For each argument in each argument pack, substitute into the
13083 pattern. */
13087 {
13089 i,
13091 in_decl);
13094 {
13097 }
13098 }
13100 /* Update ARGS to restore the substitution from parameter packs to
13101 their argument packs. */
13103 {
13110 else
13111 {
13119 /* Update the corresponding argument. */
13123 else
13125 }
13126 }
13128 /* If the dependent pack arguments were such that we end up with only a
13129 single pack expansion again, there's no need to keep it in a TREE_VEC. */
13135 }
13137 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
13138 TMPL. We do this using DECL_PARM_INDEX, which should work even with
13139 parameter packs; all parms generated from a function parameter pack will
13140 have the same DECL_PARM_INDEX. */
13142 tree
13144 {
13146 tree patparm;
13149 {
13155 }
13156 else
13157 {
13162 }
13165 }
13167 /* Make an argument pack out of the TREE_VEC VEC. */
13169 static tree
13171 {
13172 tree pack;
13176 else
13177 {
13180 }
13183 }
13185 /* Return an exact copy of template args T that can be modified
13186 independently. */
13188 static tree
13190 {
13198 {
13203 }
13209 }
13211 /* Substitute ARGS into the *_ARGUMENT_PACK orig_arg. */
13213 tree
13215 tree in_decl)
13216 {
13217 /* Substitute into each of the arguments. */
13226 else
13233 }
13235 /* Substitute ARGS into the vector or list of template arguments T. */
13237 tree
13239 {
13251 {
13253 tree new_arg;
13258 {
13259 /* Substitute into an expansion expression. */
13263 /* Add to the expanded length adjustment the number of
13264 expanded arguments. We subtract one from this
13265 measurement, because the argument pack expression
13266 itself is already counted as 1 in
13267 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
13268 the argument pack is empty. */
13270 }
13273 else
13282 }
13287 /* Make space for the expanded arguments coming from template
13288 argument packs. */
13290 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
13291 arguments for a member template.
13292 In that case each TREE_VEC in ORIG_T represents a level of template
13293 arguments, and ORIG_T won't carry any non defaulted argument count.
13294 It will rather be the nested TREE_VECs that will carry one.
13295 In other words, ORIG_T carries a non defaulted argument count only
13296 if it doesn't contain any nested TREE_VEC. */
13298 {
13302 }
13304 {
13308 {
13311 /* Now expand the template argument pack "in place". */
13314 }
13315 else
13316 {
13318 out++;
13319 }
13320 }
13323 }
13325 /* Substitute ARGS into one level PARMS of template parameters. */
13327 static tree
13329 {
13336 {
13344 }
13347 }
13349 /* Return the result of substituting ARGS into the template parameters
13350 given by PARMS. If there are m levels of ARGS and m + n levels of
13351 PARMS, then the result will contain n levels of PARMS. For
13352 example, if PARMS is `template <class T> template <class U>
13353 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
13354 result will be `template <int*, double, class V>'. */
13356 static tree
13358 {
13362 /* When substituting into a template, we must set
13363 PROCESSING_TEMPLATE_DECL as the template parameters may be
13364 dependent if they are based on one-another, and the dependency
13365 predicates are short-circuit outside of templates. */
13372 {
13381 }
13386 }
13388 /* Return the result of substituting ARGS into one template parameter
13389 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
13390 parameter and which TREE_PURPOSE is the default argument of the
13391 template parameter. */
13393 static tree
13395 {
13420 }
13422 /* Substitute the ARGS into the indicated aggregate (or enumeration)
13423 type T. If T is not an aggregate or enumeration type, it is
13424 handled as if by tsubst. IN_DECL is as for tsubst. If
13425 ENTERING_SCOPE is nonzero, T is the context for a template which
13426 we are presently tsubst'ing. Return the substituted value. */
13428 static tree
13430 tree args,
13431 tsubst_flags_t complain,
13432 tree in_decl,
13434 {
13439 {
13444 /* Fall through. */
13448 {
13449 tree argvec;
13450 tree context;
13451 tree r;
13453 /* In "sizeof(X<I>)" we need to evaluate "I". */
13454 cp_evaluated ev;
13456 /* First, determine the context for the type we are looking
13457 up. */
13460 {
13463 /* If context is a nested class inside a class template,
13464 it may still need to be instantiated (c++/33959). */
13466 }
13468 /* Then, figure out what arguments are appropriate for the
13469 type we are trying to find. For example, given:
13471 template <class T> struct S;
13472 template <class T, class U> void f(T, U) { S<U> su; }
13474 and supposing that we are instantiating f<int, double>,
13475 then our ARGS will be {int, double}, but, when looking up
13476 S we only want {double}. */
13483 {
13484 /* See maybe_dependent_member_ref. */
13491 typename_type);
13492 }
13493 else
13494 {
13498 }
13501 }
13502 else
13503 /* This is not a template type, so there's nothing to do. */
13508 }
13509 }
13513 /* Substitute into the default argument ARG (a default argument for
13514 FN), which has the indicated TYPE. */
13516 tree
13518 tsubst_flags_t complain)
13519 {
13522 /* This can happen in invalid code. */
13526 /* Shortcut {}. */
13545 /* This default argument came from a template. Instantiate the
13546 default argument here, not in tsubst. In the case of
13547 something like:
13549 template <class T>
13550 struct S {
13551 static T t();
13552 void f(T = t());
13553 };
13555 we must be careful to do name lookup in the scope of S<T>,
13556 rather than in the current class. */
13562 /* The default argument expression may cause implicitly defined
13563 member functions to be synthesized, which will result in garbage
13564 collection. We must treat this situation as if we were within
13565 the body of function so as to avoid collecting live data on the
13566 stack. */
13575 /* Make sure the default argument is reasonable. */
13588 {
13592 }
13595 }
13597 /* Substitute into all the default arguments for FN. */
13599 static void
13601 {
13602 tree arg;
13603 tree tmpl_args;
13607 /* If this function is not yet instantiated, we certainly don't need
13608 its default arguments. */
13611 /* Don't do this again for clones. */
13617 arg;
13623 complain);
13624 }
13626 /* Hash table mapping a FUNCTION_DECL to its dependent explicit-specifier. */
13629 /* Store a pair to EXPLICIT_SPECIFIER_MAP. */
13631 void
13633 {
13638 }
13640 /* Lookup an element in EXPLICIT_SPECIFIER_MAP. */
13642 static tree
13644 {
13646 }
13648 /* Given T, a FUNCTION_TYPE or METHOD_TYPE, construct and return a corresponding
13649 FUNCTION_TYPE or METHOD_TYPE whose return type is RETURN_TYPE, argument types
13650 are ARG_TYPES, and exception specification is RAISES, and otherwise is
13651 identical to T. */
13653 static tree
13656 {
13659 tree new_type;
13661 {
13664 }
13665 else
13666 {
13668 /* Don't pick up extra function qualifiers from the basetype. */
13671 {
13672 /* [temp.deduct]
13674 Type deduction may fail for any of the following
13675 reasons:
13677 -- Attempting to create "pointer to member of T" when T
13678 is not a class type. */
13681 r);
13683 }
13687 }
13693 }
13695 /* Check if the function type of DECL, a FUNCTION_DECL, agrees with the type of
13696 each of its formal parameters. If there is a disagreement then rebuild
13697 DECL's function type according to its formal parameter types, as part of a
13698 resolution for Core issues 1001/1322. */
13700 static void
13702 {
13705 {
13708 {
13712 {
13715 }
13719 }
13720 }
13731 {
13736 }
13738 {
13748 }
13756 }
13758 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
13760 static tree
13762 tree lambda_fntype)
13763 {
13768 /* Nobody should be tsubst'ing into non-template functions. */
13773 {
13776 }
13778 {
13779 /* If T is not dependent, just return it. */
13784 /* Calculate the most general template of which R is a
13785 specialization. */
13788 /* We're substituting a lambda function under tsubst_lambda_expr but not
13789 directly from it; find the matching function we're already inside.
13790 But don't do this if T is a generic lambda with a single level of
13791 template parms, as in that case we're doing a normal instantiation. */
13797 /* Calculate the complete set of arguments used to
13798 specialize R. */
13800 (DECL_TEMPLATE_RESULT
13806 /* Check to see if we already have this specialization. */
13808 {
13812 }
13814 /* We can see more levels of arguments than parameters if
13815 there was a specialization of a member template, like
13816 this:
13818 template <class T> struct S { template <class U> void f(); }
13819 template <> template <class U> void S<int>::f(U);
13821 Here, we'll be substituting into the specialization,
13822 because that's where we can find the code we actually
13823 want to generate, but we'll have enough arguments for
13824 the most general template.
13826 We also deal with the peculiar case:
13828 template <class T> struct S {
13829 template <class U> friend void f();
13830 };
13831 template <class U> void f() {}
13832 template S<int>;
13833 template void f<double>();
13835 Here, the ARGS for the instantiation of will be {int,
13836 double}. But, we only need as many ARGS as there are
13837 levels of template parameters in CODE_PATTERN. We are
13838 careful not to get fooled into reducing the ARGS in
13839 situations like:
13841 template <class T> struct S { template <class U> void f(U); }
13842 template <class T> template <> void S<T>::f(int) {}
13844 which we can spot because the pattern will be a
13845 specialization in this case. */
13852 }
13853 else
13854 {
13855 /* This special case arises when we have something like this:
13857 template <class T> struct S {
13858 friend void f<int>(int, double);
13859 };
13861 Here, the DECL_TI_TEMPLATE for the friend declaration
13862 will be an IDENTIFIER_NODE. We are being called from
13863 tsubst_friend_function, and we want only to create a
13864 new decl (R) with appropriate types so that we can call
13865 determine_specialization. */
13868 }
13885 /* If we hit excessive deduction depth, the type is bogus even if
13886 it isn't error_mark_node, so don't build a decl. */
13890 /* We do NOT check for matching decls pushed separately at this
13891 point, as they may not represent instantiations of this
13892 template, and in any case are considered separate under the
13893 discrete model. */
13897 /* Clear out the mangled name and RTL for the instantiation. */
13900 /* Leave DECL_INITIAL set on deleted instantiations. */
13905 /* Handle explicit(dependent-expr). */
13907 {
13914 }
13916 /* OpenMP UDRs have the only argument a reference to the declared
13917 type. We want to diagnose if the declared type is a reference,
13918 which is invalid, but as references to references are usually
13919 quietly merged, diagnose it here. */
13921 {
13922 tree argtype
13927 "reference type %qT in "
13931 argtype);
13932 }
13935 /* Type-conversion operator. Reconstruct the name, in
13936 case it's the name of one of the template's parameters. */
13946 {
13951 }
13960 /* If this is an instantiation of a function with internal
13961 linkage, we already know what object file linkage will be
13962 assigned to the instantiation. */
13971 /* We'll re-clone as appropriate in instantiate_template. */
13974 /* If we aren't complaining now, return on error before we register
13975 the specialization so that we'll complain eventually. */
13981 /* Associate the constraints directly with the instantiation. We
13982 don't substitute through the constraints; that's only done when
13983 they are checked. */
13985 /* Unless we're regenerating a lambda, in which case we'll set the
13986 lambda's constraints in tsubst_lambda_expr. */
13995 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
13996 this in the special friend case mentioned above where
13997 GEN_TMPL is NULL. */
13999 {
14004 tree new_r
14007 /* We instantiated this while substituting into
14008 the type earlier (template/friend54.C). */
14011 /* We're not supposed to instantiate default arguments
14012 until they are called, for a template. But, for a
14013 declaration like:
14015 template <class T> void f ()
14016 { extern void g(int i = T()); }
14018 we should do the substitution when the template is
14019 instantiated. We handle the member function case in
14020 instantiate_class_template since the default arguments
14021 might refer to other members of the class. */
14026 }
14028 {
14031 }
14032 else
14035 /* Copy the list of befriending classes. */
14039 {
14043 }
14046 {
14050 /* If this is an instantiation of a member template, clone it.
14051 If it isn't, that'll be handled by
14052 clone_constructors_and_destructors. */
14055 }
14061 /* Possibly limit visibility based on template args. */
14064 {
14068 }
14082 }
14084 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
14086 static tree
14088 tree lambda_fntype)
14089 {
14090 /* We can get here when processing a member function template,
14091 member class template, or template template parameter. */
14094 tree spec;
14095 tree tmpl_args;
14096 tree full_args;
14097 tree r;
14101 {
14102 /* Template template parameter is treated here. */
14106 /* If we get a real template back, return it. This can happen in
14107 the context of most_specialized_partial_spec. */
14110 else
14111 /* The new TEMPLATE_DECL was built in
14112 reduce_template_parm_level. */
14115 }
14118 {
14119 /* We might already have an instance of this template.
14120 The ARGS are for the surrounding class type, so the
14121 full args contain the tsubst'd args for the context,
14122 plus the innermost args from the template decl. */
14126 /* Because this is a template, the arguments will still be
14127 dependent, even after substitution. If
14128 PROCESSING_TEMPLATE_DECL is not set, the dependency
14129 predicates will short-circuit. */
14137 /* If this is a default template template argument,
14138 tsubst might not have changed anything. */
14145 {
14147 /* Type partial instantiations are stored as the type by
14148 lookup_template_class_1, not here as the template. */
14151 }
14152 }
14154 /* Make a new template decl. It will be similar to the
14155 original, but will record the current template arguments.
14156 We also create a new function declaration, which is just
14157 like the old one, but points to this new template, rather
14158 than the old one. */
14163 // Build new template info linking to the original template decl.
14165 {
14168 }
14169 else
14172 /* The template parameters for this new template are all the
14173 template parameters for the old template, except the
14174 outermost level of parameters. */
14177 complain);
14184 else
14185 {
14187 {
14190 }
14194 else
14196 }
14202 {
14203 /* For a partial specialization, we need to keep pointing to
14204 the primary template. */
14210 }
14212 {
14215 }
14216 else
14217 {
14221 }
14234 /* Record this non-type partial instantiation. */
14240 }
14242 /* True if FN is the op() for a lambda in an uninstantiated template. */
14244 bool
14246 {
14251 }
14253 /* True if FN is the substitution (via tsubst_lambda_expr) of a function for
14254 which the above is true. */
14256 bool
14258 {
14264 }
14266 /* We're instantiating a variable from template function TCTX. Return the
14267 corresponding current enclosing scope. This gets complicated because lambda
14268 functions in templates are regenerated rather than instantiated, but generic
14269 lambda functions are subsequently instantiated. */
14271 static tree
14273 {
14283 {
14294 {
14298 }
14302 }
14304 }
14306 /* Substitute the ARGS into the T, which is a _DECL. Return the
14307 result of the substitution. Issue error and warning messages under
14308 control of COMPLAIN. */
14310 static tree
14312 {
14313 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
14314 location_t saved_loc;
14319 /* Set the filename and linenumber to improve error-reporting. */
14324 {
14334 {
14342 {
14343 /* If there is a local specialization that isn't a
14344 parameter pack, it means that we're doing a "simple"
14345 substitution from inside tsubst_pack_expansion. Just
14346 return the local specialization (which will be a single
14347 parm). */
14354 /* Expand the TYPE_PACK_EXPANSION that provides the types for
14355 the parameters in this function parameter pack. */
14359 {
14362 /* Zero-length parameter packs are boring. Just substitute
14363 into the chain. */
14367 }
14368 else
14369 {
14370 /* All we did was update the type. Make a note of that. */
14373 }
14374 }
14376 /* Loop through all of the parameters we'll build. When T is
14377 a function parameter pack, LEN is the number of expanded
14378 types in EXPANDED_TYPES; otherwise, LEN is 1. */
14381 {
14388 /* We're on the Ith parameter of the function parameter
14389 pack. */
14390 {
14391 /* Get the Ith type. */
14394 /* Rename the parameter to include the index. */
14397 }
14399 /* We're dealing with a normal parameter. */
14407 {
14410 else
14413 }
14423 /* Keep track of the first new parameter we
14424 generate. That's what will be returned to the
14425 caller. */
14429 /* Build a proper chain of parameters when substituting
14430 into a function parameter pack. */
14433 }
14435 /* If cp_unevaluated_operand is set, we're just looking for a
14436 single dummy parameter, so don't keep going. */
14441 /* FIRST_R contains the start of the chain we've built. */
14443 }
14447 {
14454 {
14455 /* This field is a lambda capture pack. Return a TREE_VEC of
14456 the expanded fields to instantiate_class_template_1. */
14460 {
14463 }
14464 else
14465 {
14466 /* All we did was update the type. Make a note of that. */
14469 }
14470 }
14473 {
14476 {
14480 }
14490 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
14491 number of bits. */
14497 {
14498 /* Set up DECL_TEMPLATE_INFO so that we can get at the
14499 NSDMI in perform_member_init. Still set DECL_INITIAL
14500 so that we know there is one. */
14505 }
14506 /* We don't have to set DECL_CONTEXT here; it is set by
14507 finish_member_declaration. */
14515 }
14519 }
14523 /* We reach here only for member using decls. We also need to check
14524 uses_template_parms because DECL_DEPENDENT_P is not set for a
14525 using-declaration that designates a member of the current
14526 instantiation (c++/53549). */
14529 {
14533 {
14538 {
14542 {
14545 }
14546 else
14547 {
14550 }
14552 }
14553 }
14554 else
14555 {
14561 else
14562 {
14565 }
14566 }
14567 }
14568 else
14569 {
14572 }
14577 {
14588 {
14589 /* If this is the canonical decl, we don't have to
14590 mess with instantiations, and often we can't (for
14591 typename, template type parms and such). Note that
14592 TYPE_NAME is not correct for the above test if
14593 we've copied the type for a typedef. */
14599 }
14601 /* Check to see if we already have the specialization we
14602 need. */
14608 {
14611 {
14613 complain,
14615 /* If CTX is unchanged, then T is in fact the
14616 specialization we want. That situation occurs when
14617 referencing a static data member within in its own
14618 class. We can use pointer equality, rather than
14619 same_type_p, because DECL_CONTEXT is always
14620 canonical... */
14622 /* ... unless T is a member template; in which
14623 case our caller can be willing to create a
14624 specialization of that template represented
14625 by T. */
14629 }
14632 {
14637 argvec = (coerce_innermost_template_parms
14645 }
14646 }
14647 else
14648 {
14650 /* Subsequent calls to pushdecl will fill this in. */
14652 /* A local variable. */
14654 /* Unless this is a reference to a static variable from an
14655 enclosing function, in which case we need to fill it in now. */
14657 {
14661 }
14663 }
14664 /* If we already have the specialization we need, there is
14665 nothing more to do. */
14667 {
14670 }
14672 /* Create a new node for the specialization we need. */
14674 {
14677 else
14685 {
14686 /* Mask off any template args past the variable's context so we
14687 don't replace the auto with an unrelated argument. */
14691 /* This should never happen with the new lambda instantiation
14692 model, but keep the handling just in case. */
14695 }
14697 /* Substituting the type might have recursively instantiated this
14698 same alias (c++/86171). */
14701 {
14704 }
14705 }
14708 {
14714 {
14715 /* It may seem that this case cannot occur, since:
14717 typedef void f();
14718 void g() { f x; }
14720 declares a function, not a variable. However:
14722 typedef void f();
14723 template <typename T> void g() { T t; }
14724 template void g<f>();
14726 is an attempt to declare a variable with function
14727 type. */
14729 /* R is not yet sufficiently initialized, so we
14730 just use its name. */
14733 }
14735 /* Wait until cp_finish_decl to set this again, to handle
14736 circular dependency (template/instantiate6.C). */
14741 {
14743 /* If the DECL_VALUE_EXPR is converted to the declared type,
14744 preserve the identity so that gimplify_type_sizes works. */
14751 {
14754 }
14763 else
14767 }
14771 }
14777 /* Clear out the mangled name and RTL for the instantiation. */
14781 /* The initializer must not be expanded until it is required;
14782 see [temp.inst]. */
14786 {
14792 /* Possibly limit visibility based on template args. */
14795 {
14799 }
14801 }
14804 {
14805 /* A static data member declaration is always marked
14806 external when it is declared in-class, even if an
14807 initializer is present. We mimic the non-template
14808 processing here. */
14817 }
14818 else
14819 {
14824 }
14832 /* Preserve a typedef that names a type. */
14834 {
14838 /* An alias template specialization can be dependent
14839 even if its underlying type is not. */
14841 }
14844 }
14849 }
14850 #undef RETURN
14852 out:
14853 /* Restore the file and line information. */
14857 }
14859 /* Substitute into the complete parameter type list PARMS. */
14861 tree
14863 tree args,
14864 tsubst_flags_t complain,
14865 tree in_decl)
14866 {
14868 }
14870 /* Substitute into the ARG_TYPES of a function type.
14871 If END is a TREE_CHAIN, leave it and any following types
14872 un-substituted. */
14874 static tree
14876 tree args,
14877 tree end,
14878 tsubst_flags_t complain,
14879 tree in_decl)
14880 {
14881 tree remaining_arg_types;
14885 tree default_arg;
14896 {
14897 /* For a pack expansion, perform substitution on the
14898 entire expression. Later on, we'll handle the arguments
14899 one-by-one. */
14904 /* So that we'll spin through the parameters, one by one. */
14906 else
14907 {
14908 /* We only partially substituted into the parameter
14909 pack. Our type is TYPE_PACK_EXPANSION. */
14912 }
14913 }
14926 {
14928 {
14932 }
14934 }
14936 /* Do array-to-pointer, function-to-pointer conversion, and ignore
14937 top-level qualifiers as required. */
14940 /* We do not substitute into default arguments here. The standard
14941 mandates that they be instantiated only when needed, which is
14942 done in build_over_call. */
14945 /* Except that we do substitute default arguments under tsubst_lambda_expr,
14946 since the new op() won't have any associated template arguments for us
14947 to refer to later. */
14953 {
14954 /* We've instantiated a template before its default arguments
14955 have been parsed. This can happen for a nested template
14956 class, and is not an error unless we require the default
14957 argument in a call of this function. */
14958 remaining_arg_types =
14961 remaining_arg_types);
14962 }
14963 else
14964 remaining_arg_types =
14966 }
14969 }
14971 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
14972 *not* handle the exception-specification for FNTYPE, because the
14973 initial substitution of explicitly provided template parameters
14974 during argument deduction forbids substitution into the
14975 exception-specification:
14977 [temp.deduct]
14979 All references in the function type of the function template to the
14980 corresponding template parameters are replaced by the specified tem-
14981 plate argument values. If a substitution in a template parameter or
14982 in the function type of the function template results in an invalid
14983 type, type deduction fails. [Note: The equivalent substitution in
14984 exception specifications is done only when the function is instanti-
14985 ated, at which point a program is ill-formed if the substitution
14986 results in an invalid type.] */
14988 static tree
14990 tree args,
14991 tsubst_flags_t complain,
14992 tree in_decl)
14993 {
14994 tree return_type;
14997 /* The TYPE_CONTEXT is not used for function/method types. */
15000 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
15001 failure. */
15005 {
15006 /* Substitute the argument types. */
15018 {
15019 /* DR 1207: 'this' is in scope in the trailing return type. */
15021 }
15023 /* Substitute the return type. */
15027 {
15030 }
15031 }
15032 else
15033 /* Substitute the return type. */
15038 /* DR 486 clarifies that creation of a function type with an
15039 invalid return type is a deduction failure. */
15042 {
15044 {
15047 else
15049 }
15051 }
15054 {
15055 /* Substitute the argument types. */
15060 }
15062 /* Construct a new type node and return it. */
15065 }
15067 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
15068 ARGS into that specification, and return the substituted
15069 specification. If there is no specification, return NULL_TREE. */
15071 static tree
15073 tree args,
15074 tsubst_flags_t complain,
15075 tree in_decl,
15077 {
15078 tree specs;
15079 tree new_specs;
15084 {
15085 /* A noexcept-specifier. */
15090 {
15091 /* Defer instantiation of noexcept-specifiers to avoid
15092 excessive instantiations (c++/49107). */
15095 {
15096 /* We already partially instantiated this member template,
15097 so combine the new args with the old. */
15102 }
15103 else
15104 {
15107 }
15108 }
15109 else
15110 {
15112 {
15114 args);
15116 }
15117 new_specs = tsubst_copy_and_build
15120 }
15122 }
15124 {
15127 else
15129 {
15130 tree spec;
15135 {
15136 /* Expand the pack expansion type. */
15139 in_decl);
15145 else
15146 {
15147 /* We're substituting into a member template, so
15148 we got a TYPE_PACK_EXPANSION back. Add that
15149 expansion and move on. */
15153 expanded_specs,
15154 complain);
15157 }
15158 }
15161 {
15164 else
15169 complain);
15170 }
15173 }
15174 }
15176 }
15178 /* Substitute through a TREE_LIST of types or expressions, handling pack
15179 expansions. */
15181 tree
15183 {
15190 ;
15192 {
15196 }
15199 else
15207 ;
15209 {
15213 }
15216 else
15223 ;
15228 else
15239 /* Determine the number of arguments. */
15241 {
15244 }
15247 else
15251 {
15259 else
15261 }
15264 }
15266 /* Take the tree structure T and replace template parameters used
15267 therein with the argument vector ARGS. IN_DECL is an associated
15268 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
15269 Issue error and warning messages under control of COMPLAIN. Note
15270 that we must be relatively non-tolerant of extensions here, in
15271 order to preserve conformance; if we allow substitutions that
15272 should not be allowed, we may allow argument deductions that should
15273 not succeed, and therefore report ambiguous overload situations
15274 where there are none. In theory, we could allow the substitution,
15275 but indicate that it should have failed, and allow our caller to
15276 make sure that the right thing happens, but we don't try to do this
15277 yet.
15279 This function is used for dealing with types, decls and the like;
15280 for expressions, use tsubst_expr or tsubst_copy. */
15282 tree
15284 {
15307 else
15312 /* Reuse typedefs. We need to do this to handle dependent attributes,
15313 such as attribute aligned. */
15316 {
15320 {
15321 /* DECL represents an alias template and we want to
15322 instantiate it. */
15326 }
15330 {
15334 }
15339 else
15340 /* The typedef is from a non-template context. */
15344 {
15346 r = cp_build_qualified_type_real
15350 }
15351 else
15352 {
15353 /* We don't have an instantiation yet, so drop the typedef. */
15358 }
15359 }
15376 {
15402 {
15408 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
15409 needed. */
15415 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
15416 with TREE_SIDE_EFFECTS that indicates this is not an integral
15417 constant expression. */
15420 {
15423 }
15426 }
15432 {
15446 {
15449 /* See through ARGUMENT_PACK_SELECT arguments. */
15452 }
15457 {
15459 /* If ARG is an argument pack, we don't actually want to
15460 perform a substitution here, because substitutions
15461 for argument packs are only done
15462 element-by-element. We can get to this point when
15463 substituting the type of a non-type template
15464 parameter pack, when that type actually contains
15465 template parameter packs from an outer template, e.g.,
15467 template<typename... Types> struct A {
15468 template<Types... Values> struct B { };
15469 }; */
15473 {
15476 /* When building concept checks for the purpose of
15477 deducing placeholders, we can end up with wildcards
15478 where types are expected. Adjust this to the deduced
15479 value. */
15487 return cp_build_qualified_type_real
15489 }
15491 {
15492 /* We are processing a type constructed from a
15493 template template parameter. */
15504 /* Consider this code:
15506 template <template <class> class Template>
15507 struct Internal {
15508 template <class Arg> using Bind = Template<Arg>;
15509 };
15511 template <template <class> class Template, class Arg>
15512 using Instantiate = Template<Arg>; //#0
15514 template <template <class> class Template,
15515 class Argument>
15516 using Bind =
15517 Instantiate<Internal<Template>::template Bind,
15518 Argument>; //#1
15520 When #1 is parsed, the
15521 BOUND_TEMPLATE_TEMPLATE_PARM representing the
15522 parameter `Template' in #0 matches the
15523 UNBOUND_CLASS_TEMPLATE representing the argument
15524 `Internal<Template>::template Bind'; We then want
15525 to assemble the type `Bind<Argument>' that can't
15526 be fully created right now, because
15527 `Internal<Template>' not being complete, the Bind
15528 template cannot be looked up in that context. So
15529 we need to "store" `Bind<Argument>' for later
15530 when the context of Bind becomes complete. Let's
15531 store that in a TYPENAME_TYPE. */
15535 argvec),
15536 typename_type,
15537 complain);
15539 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
15540 are resolving nested-types in the signature of a
15541 member function templates. Otherwise ARG is a
15542 TEMPLATE_DECL and is the real template to be
15543 instantiated. */
15551 complain);
15552 return cp_build_qualified_type_real
15554 }
15557 else
15558 /* TEMPLATE_PARM_INDEX. */
15560 }
15563 /* This can happen during the attempted tsubst'ing in
15564 unify. This means that we don't yet have any information
15565 about the template parameter in question. */
15568 /* Early in template argument deduction substitution, we don't
15569 want to reduce the level of 'auto', or it will be confused
15570 with a normal template parm in subsequent deduction.
15571 Similarly, don't reduce the level of template parameters to
15572 avoid mismatches when deducing their types. */
15576 /* If we get here, we must have been looking at a parm for a
15577 more deeply nested template. Make a new version of this
15578 template parameter, but with a lower level. */
15580 {
15585 {
15587 r = cp_build_qualified_type_real
15591 }
15598 /* Break infinite recursion when substituting the constraints
15607 /* Cache the simple case of lowering a type parameter. */
15609 else
15610 {
15621 {
15622 /* Propagate constraints on placeholders since they are
15623 only instantiated during satisfaction. */
15627 {
15630 }
15631 }
15634 /* We have reduced the level of the template
15635 template parameter, but not the levels of its
15636 template parameters, so canonical_type_parameter
15637 will not be able to find the canonical template
15638 template parameter for this level. Thus, we
15639 require structural equality checking to compare
15640 TEMPLATE_TEMPLATE_PARMs. */
15644 else
15648 {
15650 /* We might need to substitute into the types of non-type
15651 template parameters. */
15663 }
15664 }
15668 /* OK, now substitute the type of the non-type parameter. We
15669 couldn't do it earlier because it might be an auto parameter,
15670 and we wouldn't need to if we had an argument. */
15679 }
15682 }
15688 /* We should never be tsubsting a binfo. */
15692 /* A vector of template arguments. */
15698 {
15702 /* [temp.deduct]
15704 Type deduction may fail for any of the following
15705 reasons:
15707 -- Attempting to create a pointer to reference type.
15708 -- Attempting to create a reference to a reference type or
15709 a reference to void.
15711 Core issue 106 says that creating a reference to a reference
15712 during instantiation is no longer a cause for failure. We
15713 only enforce this check in strict C++98 mode. */
15717 {
15720 /* We keep track of the last time we issued this error
15721 message to avoid spewing a ton of messages during a
15722 single bad template instantiation. */
15725 {
15730 else
15733 }
15736 }
15740 {
15742 {
15745 type);
15746 else
15748 type);
15749 }
15751 }
15753 {
15757 }
15759 /* In C++0x, during template argument substitution, when there is an
15760 attempt to create a reference to a reference type, reference
15761 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
15763 "If a template-argument for a template-parameter T names a type
15764 that is a reference to a type A, an attempt to create the type
15765 'lvalue reference to cv T' creates the type 'lvalue reference to
15766 A,' while an attempt to create the type type rvalue reference to
15767 cv T' creates the type T"
15768 */
15769 r = cp_build_reference_type
15772 else
15777 /* Will this ever be needed for TYPE_..._TO values? */
15781 }
15783 {
15786 {
15787 /* [temp.deduct]
15789 Type deduction may fail for any of the following
15790 reasons:
15792 -- Attempting to create "pointer to member of T" when T
15793 is not a class type. */
15797 }
15799 {
15803 }
15805 {
15809 }
15812 {
15813 /* The type of the implicit object parameter gets its
15814 cv-qualifiers from the FUNCTION_TYPE. */
15815 tree memptr;
15816 tree method_type
15821 complain);
15822 }
15823 else
15826 complain);
15827 }
15830 {
15831 tree fntype;
15832 tree specs;
15837 /* Substitute the exception specification. */
15845 }
15847 {
15852 /* As an optimization, we avoid regenerating the array type if
15853 it will obviously be the same as T. */
15857 /* These checks should match the ones in create_array_type_for_decl.
15859 [temp.deduct]
15861 The deduction may fail for any of the following reasons:
15863 -- Attempting to create an array with an element type that
15864 is void, a function type, or a reference type, or [DR337]
15865 an abstract class type. */
15871 {
15875 }
15884 {
15887 }
15890 }
15893 {
15896 {
15902 {
15907 }
15909 }
15910 else
15922 {
15926 }
15928 {
15929 /* Normally, make_typename_type does not require that the CTX
15930 have complete type in order to allow things like:
15932 template <class T> struct S { typename S<T>::X Y; };
15934 But, such constructs have already been resolved by this
15935 point, so here CTX really should have complete type, unless
15936 it's a partial instantiation. */
15939 {
15943 }
15944 }
15951 {
15954 }
15957 {
15959 {
15963 else
15965 }
15967 {
15971 else
15973 }
15974 }
15976 return cp_build_qualified_type_real
15978 }
15981 {
15993 }
15996 {
15997 tree type;
16013 complain);
16014 }
16017 {
16018 tree type;
16037 else
16038 {
16042 /* In a template ~id could be either a complement expression
16043 or an unqualified-id naming a destructor; if instantiating
16044 it produces an expression, it's not an id-expression or
16045 member access. */
16048 }
16053 }
16056 {
16060 }
16079 /* We should use one of the expression tsubsts for these codes. */
16085 }
16086 }
16088 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
16089 expression on the left-hand side of the "." or "->" operator. We
16090 only do the lookup if we had a dependent BASELINK. Otherwise we
16091 adjust it onto the instantiated heirarchy. */
16093 static tree
16096 {
16108 {
16115 }
16122 {
16128 /* Treat as-if non-dependent below. */
16132 complain);
16134 {
16140 }
16144 }
16145 else
16146 /* We're going to overwrite pieces below, make a duplicate. */
16149 /* If lookup found a single function, mark it as used at this point.
16150 (If lookup found multiple functions the one selected later by
16151 overload resolution will be marked as used at that point.) */
16153 {
16159 /* We might have instantiated an auto function. */
16161 }
16164 {
16165 /* Add back the template arguments, if present. */
16170 /* Update the conversion operator type. */
16172 }
16178 {
16180 qualifying_scope,
16181 object_type);
16183 /* We need to call adjust_result_of_qualified_name_lookup in case the
16184 destructor names a base class, but we unset BASELINK_QUALIFIED_P
16185 so that we still get virtual function binding. */
16187 }
16190 }
16192 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
16193 true if the qualified-id will be a postfix-expression in-and-of
16194 itself; false if more of the postfix-expression follows the
16195 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
16196 of "&". */
16198 static tree
16202 {
16203 tree expr;
16204 tree scope;
16205 tree name;
16207 tree template_args;
16212 /* Figure out what name to look up. */
16215 {
16224 }
16225 else
16226 {
16229 }
16231 /* Substitute into the qualifying scope. When there are no ARGS, we
16232 are just trying to simplify a non-dependent expression. In that
16233 case the qualifying scope may be dependent, and, in any case,
16234 substituting will not help. */
16237 {
16240 }
16241 else
16245 {
16252 }
16255 {
16257 {
16258 /* A BIT_NOT_EXPR is used to represent a destructor. */
16260 {
16264 }
16265 else
16268 }
16269 else
16273 {
16275 {
16279 }
16281 }
16282 }
16285 {
16289 /* Remember that there was a reference to this entity. */
16292 }
16295 {
16301 }
16304 {
16305 /* We may be repeating a check already done during parsing, but
16306 if it was well-formed and passed then, it will pass again
16307 now, and if it didn't, we wouldn't have got here. The case
16308 we want to catch is when we couldn't tell then, and can now,
16309 namely when templ prior to substitution was an
16310 identifier. */
16316 complain);
16317 else
16319 }
16325 {
16326 expr = (adjust_result_of_qualified_name_lookup
16328 expr = (finish_qualified_id_expr
16332 }
16334 /* Expressions do not generally have reference type. */
16336 /* However, if we're about to form a pointer-to-member, we just
16337 want the referenced member referenced. */
16347 }
16349 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
16350 initializer, DECL is the substituted VAR_DECL. Other arguments are as
16351 for tsubst. */
16353 static tree
16356 {
16365 {
16367 {
16369 {
16374 }
16375 }
16377 {
16378 /* If we had an initializer but it
16379 instantiated to nothing,
16380 value-initialize the object. This will
16381 only occur when the initializer was a
16382 pack expansion where the parameter packs
16383 used in that expansion were of length
16384 zero. */
16390 }
16391 }
16394 }
16396 /* If T is a reference to a dependent member of the current instantiation C and
16397 we are trying to refer to that member in a partial instantiation of C,
16398 return a SCOPE_REF; otherwise, return NULL_TREE.
16400 This can happen when forming a C++17 deduction guide, as in PR96199. */
16402 static tree
16404 tree in_decl)
16405 {
16419 }
16421 /* Like tsubst, but deals with expressions. This function just replaces
16422 template parms; to finish processing the resultant expression, use
16423 tsubst_copy_and_build or tsubst_expr. */
16425 static tree
16427 {
16429 tree r;
16437 {
16442 {
16443 /* We get here for a use of 'this' in an NSDMI. */
16447 /* This can happen for a parameter name used later in a function
16448 declaration (such as in a late-specified return type). Just
16449 make a dummy decl, since it's only used for its type. */
16452 /* Give it the template pattern as its context; its true context
16453 hasn't been instantiated yet and this is good enough for
16454 mangling. */
16456 }
16465 {
16466 tree enum_type;
16467 tree v;
16471 /* There is no need to substitute into namespace-scope
16472 enumerators. */
16475 /* If ARGS is NULL, then T is known to be non-dependent. */
16482 /* Unfortunately, we cannot just call lookup_name here.
16483 Consider:
16485 template <int I> int f() {
16486 enum E { a = I };
16487 struct S { void g() { E e = a; } };
16488 };
16490 When we instantiate f<7>::S::g(), say, lookup_name is not
16491 clever enough to find f<7>::a. */
16492 enum_type
16502 /* We didn't find the name. That should never happen; if
16503 name-lookup found it during preliminary parsing, we
16504 should find it again here during instantiation. */
16506 }
16511 {
16512 tree ctx;
16517 {
16520 {
16524 }
16526 }
16527 }
16539 {
16540 /* Local specialization will have been created when we
16541 instantiated the DECL_EXPR_DECL. */
16545 }
16548 {
16551 {
16552 /* First try name lookup to find the instantiation. */
16555 {
16557 {
16558 /* During error-recovery we may find a non-variable,
16559 even an OVERLOAD: just bail out and avoid ICEs and
16560 duplicate diagnostics (c++/62207). */
16563 }
16565 {
16566 /* Make sure the one we found is the one we want. */
16570 }
16571 }
16575 else
16576 {
16577 /* This can happen for a variable used in a
16578 late-specified return type of a local lambda, or for a
16579 local static or constant. Building a new VAR_DECL
16580 should be OK in all those cases. */
16583 /* Avoid infinite recursion (79640). */
16586 {
16587 /* We can't call cp_finish_decl, so handle the
16588 initializer by hand. */
16603 }
16610 }
16611 /* Remember this for subsequent uses. */
16614 }
16617 }
16618 else
16642 {
16643 /* Template template argument like the following example need
16644 special treatment:
16646 template <template <class> class TT> struct C {};
16647 template <class T> struct D {
16648 template <class U> struct E {};
16649 C<E> c; // #1
16650 };
16651 D<int> d; // #2
16653 We are processing the template argument `E' in #1 for
16654 the template instantiation #2. Originally, `E' is a
16655 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
16656 have to substitute this with one having context `D<int>'. */
16660 {
16661 /* When rewriting a constructor into a deduction guide, a
16662 non-dependent name can become dependent, so memtmpl<args>
16663 becomes context::template memtmpl<args>. */
16667 }
16669 }
16670 else
16671 /* Ordinary template template argument. */
16676 {
16677 /* Handle location wrappers by substituting the wrapped node
16678 first, *then* reusing the resulting type. Doing the type
16679 first ensures that we handle template parameters and
16680 parameter pack expansions. */
16682 {
16686 }
16690 {
16691 /* Wrapper to make a C++20 template parameter object const. */
16694 {
16697 }
16698 else
16699 {
16704 }
16705 }
16706 /* force_paren_expr can also create a VIEW_CONVERT_EXPR. */
16708 {
16713 }
16714 /* We shouldn't see any other uses of these in templates. */
16716 }
16726 {
16730 }
16735 {
16744 /* We only want to compute the number of arguments. */
16747 else
16754 {
16756 /* Set TREE_USED for the benefit of -Wunused. */
16760 }
16768 {
16773 else
16781 else
16786 }
16787 else
16789 }
16791 {
16799 }
16800 /* Fall through */
16816 {
16823 }
16826 {
16827 tree object;
16828 tree name;
16833 {
16837 }
16840 {
16850 }
16855 in_decl);
16856 else
16859 }
16895 {
16899 }
16902 {
16907 }
16910 {
16914 }
16917 {
16925 }
16931 {
16938 }
16941 {
16948 }
16951 {
16958 }
16961 {
16962 /* Substituted template arguments */
16971 }
16974 {
16994 }
17019 /* Fall through. */
17022 {
17025 }
17026 else
17030 /* This is handled by tsubst_copy_and_build. */
17034 {
17038 }
17041 /* We shouldn't have built any of these during initial template
17042 generation. Instead, they should be built during instantiation
17043 in response to the saved STMT_IS_FULL_EXPR_P setting. */
17047 {
17057 }
17074 {
17075 /* Instantiate any typedefs in the type. */
17080 }
17083 {
17087 {
17090 }
17092 }
17095 /* These can sometimes show up in a partial instantiation, but never
17096 involve template parms. */
17112 /* ??? There's no point in copying it for now, but maybe some
17113 day it will contain more information, such as a pointer back
17114 to the containing function, inlined copy or so. */
17123 /* We shouldn't get here, but keep going if !flag_checking. */
17127 }
17128 }
17130 /* Helper function for tsubst_omp_clauses, used for instantiation of
17131 OMP_CLAUSE_DECL of clauses. */
17133 static tree
17136 {
17140 /* Handle OpenMP iterators. */
17144 {
17145 tree ret;
17148 else
17149 {
17153 {
17168 }
17172 }
17176 }
17178 /* Handle an OpenMP array section represented as a TREE_LIST (or
17179 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
17180 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
17181 TREE_LIST. We can handle it exactly the same as an array section
17182 (purpose, value, and a chain), even though the nomenclature
17183 (low_bound, length, etc) is different. */
17185 {
17186 tree low_bound
17201 }
17204 /* Undo convert_from_reference tsubst_expr could have called. */
17210 }
17212 /* Like tsubst_copy, but specifically for OpenMP clauses. */
17214 static tree
17217 {
17223 {
17229 {
17232 {
17238 }
17239 /* FALLTHRU */
17292 {
17295 {
17302 }
17303 else
17305 }
17325 {
17328 }
17333 else
17336 in_decl,
17364 }
17367 {
17383 /* tsubst_expr on SCOPE_REF results in returning
17384 finish_non_static_data_member result. Undo that here. */
17388 {
17393 {
17397 CASE_CONVERT:
17406 /* FALLTHRU */
17410 }
17411 }
17417 {
17420 {
17423 }
17424 }
17428 }
17429 }
17433 {
17438 {
17441 }
17442 }
17444 }
17446 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
17448 static tree
17450 tree in_decl)
17451 {
17452 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
17472 {
17475 else
17476 {
17480 }
17481 }
17486 #undef RECUR
17487 }
17489 /* Used to temporarily communicate the list of #pragma omp parallel
17490 clauses to #pragma omp for instantiation if they are combined
17491 together. */
17498 /* Substitute one OMP_FOR iterator. */
17500 static bool
17505 {
17506 #define RECUR(NODE) \
17507 tsubst_expr ((NODE), args, complain, in_decl, \
17508 integral_constant_expression_p)
17520 {
17523 {
17528 {
17538 else
17540 {
17542 {
17548 }
17551 }
17552 }
17553 }
17557 }
17559 {
17560 /* We need to jump through some hoops to handle declarations in the
17561 init-statement, since we might need to handle auto deduction,
17562 but we need to keep control of initialization. */
17566 }
17567 else
17568 {
17570 {
17573 {
17577 {
17581 CASE_CONVERT:
17589 {
17592 }
17593 /* FALLTHRU */
17597 }
17598 }
17599 }
17600 else
17602 }
17604 {
17610 }
17611 else
17615 {
17621 NULL_TREE);
17622 else
17624 }
17627 {
17634 {
17639 }
17642 }
17652 {
17654 {
17655 /* Declare the variable, but don't let that initialize it. */
17660 }
17663 {
17667 {
17676 }
17677 else
17681 {
17686 }
17687 else
17691 }
17697 }
17700 {
17701 /* Declare and initialize the variable. */
17704 }
17706 {
17711 {
17713 {
17719 {
17722 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
17727 }
17730 {
17732 decl);
17734 }
17737 {
17739 decl);
17741 }
17742 else
17744 }
17747 }
17749 {
17752 ? OMP_CLAUSE_LASTPRIVATE
17757 {
17760 }
17761 }
17762 }
17765 {
17769 }
17770 else
17774 {
17785 {
17793 }
17794 else
17800 {
17806 }
17810 {
17818 }
17819 else
17825 }
17834 #undef RECUR
17835 }
17837 /* Helper function of tsubst_expr, find OMP_TEAMS inside
17838 of OMP_TARGET's body. */
17840 static tree
17842 {
17845 {
17854 }
17856 }
17858 /* Helper function for tsubst_expr. For decomposition declaration
17859 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
17860 also the corresponding decls representing the identifiers
17861 of the decomposition declaration. Return DECL if successful
17862 or error_mark_node otherwise, set *FIRST to the first decl
17863 in the list chained through DECL_CHAIN and *CNT to the number
17864 of such decls. */
17866 static tree
17870 {
17875 decl2
17880 {
17882 {
17885 }
17897 else
17898 {
17902 }
17909 {
17912 }
17913 else
17915 }
17918 }
17920 /* Return the proper local_specialization for init-capture pack DECL. */
17922 static tree
17924 {
17925 /* We handle normal pack captures by forwarding to the specialization of the
17926 captured parameter. We can't do that for pack init-captures; we need them
17927 to have their own local_specialization. We created the individual
17928 VAR_DECLs (if any) under build_capture_proxy, and we need to collect them
17929 when we process the DECL_EXPR for the pack init-capture in the template.
17930 So, how do we find them? We don't know the capture proxy pack when
17931 building the individual resulting proxies, and we don't know the
17932 individual proxies when instantiating the pack. What we have in common is
17933 the FIELD_DECL.
17935 So...when we instantiate the FIELD_DECL, we stick the result in
17936 local_specializations. Then at the DECL_EXPR we look up that result, see
17937 how many elements it has, synthesize the names, and look them up. */
17951 {
17956 }
17958 {
17963 else
17965 }
17967 }
17969 /* Like tsubst_copy for expressions, etc. but also does semantic
17970 processing. */
17972 tree
17975 {
17976 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
17977 #define RECUR(NODE) \
17978 tsubst_expr ((NODE), args, complain, in_decl, \
17979 integral_constant_expression_p)
17982 tree r;
17983 location_t loc;
17995 {
17997 {
17998 tree_stmt_iterator i;
18002 }
18033 else
18042 {
18044 tree init;
18050 {
18051 /* We cannot have a member-using decl here (until 'using
18052 enum T' is a thing). */
18055 /* This must be a non-dependent using-decl, and we'll have
18056 used the names it found during template parsing. We do
18057 not want to do the lookup again, because we might not
18058 find the things we found then. (Again, using enum T
18059 might mean we have to do things here.) */
18063 }
18066 {
18067 /* We're in tsubst_lambda_expr, we've already inserted a new
18068 capture proxy, so look it up and register it. */
18069 tree inst;
18071 {
18075 }
18077 {
18078 inst = (retrieve_local_specialization
18082 }
18083 else
18088 }
18095 /* Don't copy the old closure; we'll create a new one in
18096 tsubst_lambda_expr. */
18098 else
18099 {
18103 {
18104 /* By marking the declaration as instantiated, we avoid
18105 trying to instantiate it. Since instantiate_decl can't
18106 handle local variables, and since we've already done
18107 all that needs to be done, that's the right thing to
18108 do. */
18113 /* Anonymous aggregates are a special case. */
18116 {
18119 {
18123 }
18125 }
18130 {
18138 }
18139 else
18140 {
18156 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
18162 /* In a non-template function, VLA type declarations are
18163 handled in grokdeclarator; for templates, handle them
18164 now. */
18171 }
18172 }
18173 }
18176 }
18186 {
18190 }
18195 {
18196 /* Construct another range_for, if this is not a final
18197 substitution (for inside a generic lambda of a
18198 template). Otherwise convert to a regular for. */
18200 stmt = (processing_template_decl
18217 {
18223 }
18224 else
18225 {
18231 }
18237 }
18244 {
18248 }
18254 {
18258 }
18273 {
18274 /* We're partially instantiating a generic lambda, but the condition
18275 of the constexpr if is still dependent. Don't substitute into the
18276 branches now, just remember the template arguments. */
18284 }
18287 else
18288 {
18296 }
18302 {
18312 }
18320 else
18328 else
18349 {
18355 {
18360 }
18361 }
18365 {
18367 tree label;
18374 }
18380 /* Computed goto's must be tsubst'd into. On the other hand,
18381 non-computed gotos must not be; the identifier in question
18382 will have no binding. */
18384 else
18390 {
18407 }
18412 {
18417 }
18418 else
18419 {
18424 else
18431 else
18437 else
18439 }
18443 {
18447 {
18449 /* Prevent instantiate_decl from trying to instantiate
18450 this variable. We've already done all that needs to be
18451 done. */
18454 }
18459 }
18465 {
18466 /* Local classes are not independent templates; they are
18467 instantiated along with their containing function. And this
18468 way we don't have to deal with pushing out of one local class
18469 to instantiate a member of another local class. */
18470 /* Closures are handled by the LAMBDA_EXPR. */
18480 }
18484 {
18485 tree condition;
18488 condition =
18490 args,
18499 }
18506 in_decl);
18528 {
18535 }
18551 {
18565 in_decl);
18567 {
18574 }
18585 any_range_for
18589 integral_constant_expression_p);
18593 {
18602 }
18603 else
18608 else
18615 else
18616 {
18624 }
18627 t));
18629 }
18634 /* FALLTHRU */
18643 in_decl);
18645 {
18650 }
18651 else
18652 {
18656 }
18661 {
18663 "%<#pragma omp critical%> with %<hint%> clause requires "
18666 }
18677 {
18680 {
18685 }
18686 else
18687 {
18691 }
18693 }
18694 else
18696 OMP_CLAUSE_DEPEND_SOURCE,
18705 in_decl);
18716 {
18719 {
18720 /* For combined target teams, ensure the num_teams and
18721 thread_limit clause expressions are evaluated on the host,
18722 before entering the target construct. */
18723 tree c;
18729 {
18738 OMP_CLAUSE_FIRSTPRIVATE);
18742 }
18743 }
18744 }
18791 /* FALLTHRU */
18809 {
18814 {
18817 }
18823 }
18824 else
18825 {
18832 {
18835 }
18838 {
18843 {
18846 }
18852 }
18853 else
18854 {
18858 }
18861 }
18865 {
18871 {
18875 {
18880 }
18884 }
18885 else
18886 {
18891 }
18892 }
18896 {
18900 }
18913 /* If the first operand was a statement, we're done with it. */
18917 complain));
18934 integral_constant_expression_p));
18935 }
18938 out:
18941 #undef RECUR
18942 #undef RETURN
18943 }
18945 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
18946 function. For description of the body see comment above
18947 cp_parser_omp_declare_reduction_exprs. */
18949 static void
18951 {
18957 tree_stmt_iterator tsi;
18968 {
18975 /* tsubsting a local var_decl leaves DECL_CONTEXT null, as we
18976 expect to be pushing it. */
18989 }
18991 {
19011 }
19012 }
19014 /* T is a postfix-expression that is not being used in a function
19015 call. Return the substituted version of T. */
19017 static tree
19019 tsubst_flags_t complain,
19020 tree in_decl)
19021 {
19025 else
19031 }
19033 /* Subroutine of tsubst_lambda_expr: add the FIELD/INIT capture pair to the
19034 LAMBDA_EXPR_CAPTURE_LIST passed in LIST. Do deduction for a previously
19035 dependent init-capture. */
19037 static void
19039 tsubst_flags_t complain)
19040 {
19042 {
19045 {
19049 }
19056 }
19058 }
19060 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
19061 instantiation context. Instantiating a pack expansion containing a lambda
19062 might result in multiple lambdas all based on the same lambda in the
19063 template. */
19065 tree
19067 {
19087 {
19092 else
19105 {
19106 /* For a VLA, simply tsubsting the field type won't work, we need to
19107 go through add_capture again. XXX do we want to do this for all
19108 captures? */
19109 tree name = (get_identifier
19117 }
19124 {
19125 /* Remember these for when we've pushed local_specializations. */
19128 }
19134 {
19142 complain);
19143 }
19144 else
19145 {
19147 complain);
19151 }
19152 }
19159 /* A lambda in a default argument outside a class gets no
19160 LAMBDA_EXPR_EXTRA_SCOPE, as specified by the ABI. But
19161 tsubst_default_argument calls start_lambda_scope, so we need to
19162 specifically ignore it here, and use the global scope. */
19164 else
19167 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
19185 else
19186 {
19187 /* The body of a lambda-expression is not a subexpression of the
19188 enclosing expression. Parms are to have DECL_CHAIN tsubsted,
19189 which would be skipped if cp_unevaluated_operand. */
19190 cp_evaluated ev;
19192 /* Fix the type of 'this'. */
19198 {
19201 {
19204 }
19207 }
19208 else
19209 {
19213 {
19216 }
19218 }
19221 {
19222 /* Substitute into the lambda's constraints. */
19229 }
19231 /* Let finish_function set this. */
19237 else
19238 /* Still increment function_depth so that we don't GC in the
19239 middle of an expression. */
19246 /* Now record them for lookup_init_capture_pack. */
19249 {
19253 }
19259 {
19260 /* We might not partially instantiate some parts of the function, so
19261 copy these flags from the original template. */
19267 }
19269 /* [temp.deduct] A lambda-expression appearing in a function type or a
19270 template parameter is not considered part of the immediate context for
19271 the purposes of template argument deduction. */
19281 else
19284 /* The capture list was built up in reverse order; fix that now. */
19291 }
19293 out:
19299 }
19301 /* Like tsubst but deals with expressions and performs semantic
19302 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)" or
19303 "F<TARGS> (ARGS)". */
19305 tree
19307 tree args,
19308 tsubst_flags_t complain,
19309 tree in_decl,
19312 {
19313 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
19314 #define RECUR(NODE) \
19315 tsubst_copy_and_build (NODE, args, complain, in_decl, \
19317 integral_constant_expression_p)
19320 location_t save_loc;
19329 /* N3276 decltype magic only applies to calls at the top level or on the
19330 right side of a comma. */
19335 {
19338 /* Fall through. */
19340 {
19341 tree decl;
19342 cp_id_kind idk;
19347 {
19350 }
19352 /* Look up the name. */
19355 /* By convention, expressions use ERROR_MARK_NODE to indicate
19356 failure, not NULL_TREE. */
19362 integral_constant_expression_p,
19370 input_location);
19374 {
19378 }
19380 }
19383 {
19384 tree object;
19387 function_p,
19388 integral_constant_expression_p);
19397 {
19402 }
19405 {
19412 /* If we built a function concept check, return the underlying
19413 template-id. So we can evaluate it as a function call. */
19418 }
19421 {
19423 complain);
19426 }
19429 {
19432 }
19433 else
19442 {
19443 /* C++20 P0846: we can encounter an IDENTIFIER_NODE here when
19444 name lookup found nothing when parsing the template name. */
19447 }
19448 else
19450 }
19453 {
19457 {
19458 /* A type conversion to reference type will be enclosed in
19459 such an indirect ref, but the substitution of the cast
19460 will have also added such an indirect ref. */
19462 }
19463 else
19471 }
19474 {
19478 }
19481 {
19485 {
19490 }
19492 /* We'll pass this to convert_nontype_argument again, we don't need
19493 to actually perform any conversion here. */
19501 flags));
19502 }
19505 {
19511 }
19518 {
19519 tree type;
19525 {
19530 }
19537 {
19557 }
19560 }
19593 else
19595 in_decl);
19629 {
19630 /* If T was type-dependent, suppress warnings that depend on the range
19631 of the types involved. */
19645 tree r = build_x_binary_op
19647 op0,
19649 ? ERROR_MARK
19651 op1,
19653 ? ERROR_MARK
19661 }
19664 {
19672 }
19688 /* Fall through */
19691 {
19692 tree r;
19700 {
19701 /* When there are no ARGS, we are trying to evaluate a
19702 non-dependent expression from the parser. Trying to do
19703 the substitutions may not work. */
19706 }
19707 else
19708 {
19713 else
19716 /*integral_constant_expression_p=*/
19720 }
19725 else
19730 {
19732 {
19734 {
19738 }
19739 else
19743 }
19745 }
19747 }
19750 {
19760 }
19776 {
19780 tree r = build_x_modify_expr
19783 /* TREE_NO_WARNING must be set if either the expression was
19784 parenthesized or it uses an operator such as >>= rather
19785 than plain assignment. In the former case, it was already
19786 set and must be copied. In the latter case,
19787 build_x_modify_expr sets it and it must not be reset
19788 here. */
19793 }
19798 /* Remember that there was a reference to this entity. */
19805 {
19810 tree ret;
19817 else
19818 {
19822 }
19824 /* If there was an initializer in the original tree, but it
19825 instantiated to an empty list, then we should pass a
19826 non-NULL empty vector to tell build_new that it was an
19827 empty initializer() rather than no initializer. This can
19828 only happen when the initializer is a pack expansion whose
19829 parameter packs are of length zero. */
19832 else
19833 {
19837 else
19838 {
19841 }
19842 }
19844 /* Avoid passing an enclosing decl to valid_array_size_p. */
19851 complain);
19859 }
19862 {
19868 complain));
19869 }
19872 {
19876 integral_constant_expression_p);
19878 op0,
19881 }
19884 {
19885 tree function;
19889 tree ret;
19892 /* Internal function with no arguments. */
19896 /* When we parsed the expression, we determined whether or
19897 not Koenig lookup should be performed. */
19900 {
19903 }
19905 {
19910 }
19912 {
19913 /* Do nothing; calling tsubst_copy_and_build on an identifier
19914 would incorrectly perform unqualified lookup again.
19916 Note that we can also have an IDENTIFIER_NODE if the earlier
19917 unqualified lookup found a member function; in that case
19918 koenig_p will be false and we do want to do the lookup
19919 again to find the instantiated member function.
19921 FIXME but doing that causes c++/15272, so we need to stop
19922 using IDENTIFIER_NODE in that situation. */
19924 }
19925 else
19926 {
19928 {
19934 }
19935 else
19940 /* Avoid error about taking the address of a constructor. */
19944 in_decl,
19946 integral_constant_expression_p);
19950 }
19953 releasing_vec call_args;
19955 {
19960 else
19961 {
19962 /* Expand the pack expansion and push each entry onto
19963 CALL_ARGS. */
19966 {
19971 {
19976 }
19977 }
19978 else
19979 {
19980 /* A partial substitution. Add one entry. */
19982 }
19983 }
19984 }
19986 /* Stripped-down processing for a call in a thunk. Specifically, in
19987 the thunk template for a generic lambda. */
19989 {
19990 /* Now that we've expanded any packs, the number of call args
19991 might be different. */
19995 {
20002 }
20003 /* We aren't going to do normal overload resolution, so force the
20004 template-id to resolve. */
20007 {
20008 /* In a thunk, pass through args directly, without any
20009 conversions. */
20014 }
20016 {
20017 /* If there are no other args, just push 'this'. */
20020 else
20021 {
20022 /* Otherwise, shift the other args over to make room. */
20028 }
20029 }
20032 /* The thunk location is not interesting. */
20039 }
20041 /* We do not perform argument-dependent lookup if normal
20042 lookup finds a non-function, in accordance with the
20043 resolution of DR 218. */
20046 /* If lookup found a member function, the Koenig lookup is
20047 not appropriate, even if an unqualified-name was used
20048 to denote the function. */
20051 /* C++20 P0846: Lookup found nothing. */
20054 /* Only do this when substitution turns a dependent call
20055 into a non-dependent call. */
20065 {
20069 {
20070 /* For backwards compatibility and good diagnostics, try
20071 the unqualified lookup again if we aren't in SFINAE
20072 context. */
20073 tree unq = (tsubst_copy_and_build
20075 integral_constant_expression_p));
20080 {
20081 /* In a lambda fn, we have to be careful to not
20082 introduce new this captures. Legacy code can't
20083 be using lambdas anyway, so it's ok to be
20084 stricter. */
20089 "and no declarations were found by "
20090 "argument-dependent lookup at the point "
20097 else
20101 {
20112 {
20115 "declarations in dependent base %qT are "
20121 else
20125 }
20126 else
20128 "%qD declared here, later in the "
20132 }
20135 }
20136 }
20138 {
20142 }
20143 }
20145 /* Remember that there was a reference to this entity. */
20151 /* Put back tf_decltype for the actual call. */
20156 {
20160 {
20162 "wrong number of arguments to "
20165 }
20166 else
20174 {
20176 "wrong number of arguments to "
20180 }
20184 complain);
20190 /* Unsupported internal function with arguments. */
20192 }
20197 complain);
20199 {
20214 complain);
20215 else
20216 ret = (build_new_method_call
20221 complain));
20222 }
20224 {
20225 /* FUNCTION is a template-id referring to a concept definition. */
20230 /* Calls to standard and variable concepts should have been
20231 previously diagnosed. */
20234 /* Ensure the result is wrapped as a call expression. */
20236 }
20237 else
20240 koenig_p,
20241 complain);
20244 {
20249 {
20254 }
20255 }
20258 }
20261 {
20268 {
20270 {
20275 }
20276 else
20277 {
20282 }
20284 }
20285 else
20286 {
20289 }
20294 }
20297 {
20302 input_location));
20303 }
20309 {
20310 tree object;
20311 tree object_type;
20312 tree member;
20313 tree r;
20317 /* Remember that there was a reference to this entity. */
20328 else
20334 {
20339 }
20343 {
20345 {
20350 {
20353 }
20355 {
20360 }
20361 }
20362 }
20365 {
20366 /* Lookup the template functions now that we know what the
20367 scope is. */
20374 {
20377 args);
20378 member = (adjust_result_of_qualified_name_lookup
20380 object_type));
20381 }
20382 else
20383 {
20385 input_location);
20387 }
20388 }
20392 {
20394 {
20398 else
20401 }
20403 }
20407 complain);
20411 }
20418 {
20426 tree r;
20431 /* We do not want to process the index of aggregate
20432 initializers as they are identifier nodes which will be
20433 looked up by digest_init. */
20437 {
20440 }
20445 {
20447 /* An identifier index is looked up in the type
20448 being initialized, not the current scope. */
20453 {
20454 /* Substitute into the pack expansion. */
20456 in_decl);
20460 ;
20462 /* Just move the argument into place. */
20464 else
20465 {
20466 /* Update the length of the final CONSTRUCTOR
20467 arguments vector, and note that we will need to
20468 copy.*/
20471 }
20472 }
20473 else
20475 }
20478 {
20483 {
20485 {
20490 }
20491 else
20493 }
20494 }
20502 {
20507 }
20511 }
20514 {
20517 {
20520 }
20521 else
20522 {
20525 }
20526 }
20531 /* Fall through */
20534 {
20536 /* ??? We're doing a subset of finish_id_expression here. */
20538 /* Replace an evaluated use of the thread_local variable with
20539 a call to its wrapper. */
20545 /* If the original type was a reference, we'll be wrapped in
20546 the appropriate INDIRECT_REF. */
20549 }
20552 {
20556 }
20559 {
20560 tree object_ptr
20567 }
20574 {
20581 }
20584 {
20590 integral_constant_expression_p);
20594 /* If the resulting list of expression statement is empty,
20595 fold it further into void_node. */
20600 }
20603 {
20605 {
20606 /* We don't have a full set of template arguments yet; don't touch
20607 the lambda at all. */
20610 }
20614 }
20617 /* We can get here for a constant initializer of non-dependent type.
20618 FIXME stop folding in cp_parser_initializer_clause. */
20619 {
20621 complain);
20623 }
20627 integral_constant_expression_p));
20633 {
20638 complain));
20639 }
20642 {
20645 }
20648 /* No need to substitute further, a RANGE_EXPR will always be built
20649 with constant operands. */
20655 /* We need to do this here as well as in tsubst_copy so we get the
20656 other tsubst_copy_and_build semantics for a PARM_DECL operand. */
20659 /* fallthrough. */
20662 /* Handle Objective-C++ constructs, if appropriate. */
20663 {
20664 tree subst
20669 }
20671 }
20673 #undef RECUR
20674 #undef RETURN
20675 out:
20678 }
20680 /* Verify that the instantiated ARGS are valid. For type arguments,
20681 make sure that the type's linkage is ok. For non-type arguments,
20682 make sure they are constants if they are integral or enumerations.
20683 Emit an error under control of COMPLAIN, and return TRUE on error. */
20685 static bool
20687 {
20691 {
20701 }
20703 {
20704 /* [basic.link]: A name with no linkage (notably, the name
20705 of a class or enumeration declared in a local scope)
20706 shall not be used to declare an entity with linkage.
20707 This implies that names with no linkage cannot be used as
20708 template arguments
20710 DR 757 relaxes this restriction for C++0x. */
20715 {
20716 /* DR 488 makes use of a type with no linkage cause
20717 type deduction to fail. */
20719 {
20722 else
20725 }
20727 }
20728 /* In order to avoid all sorts of complications, we do not
20729 allow variably-modified types as template arguments. */
20731 {
20735 }
20736 }
20737 /* Class template and alias template arguments should be OK. */
20739 ;
20740 /* A non-type argument of integral or enumerated type must be a
20741 constant. */
20746 {
20750 }
20752 }
20754 static bool
20756 {
20761 {
20764 }
20768 }
20770 /* We're out of SFINAE context now, so generate diagnostics for the access
20771 errors we saw earlier when instantiating D from TMPL and ARGS. */
20773 static void
20775 {
20787 }
20789 /* Instantiate the indicated variable, function, or alias template TMPL with
20790 the template arguments in TARG_PTR. */
20792 static tree
20794 {
20796 tree fndecl;
20797 tree gen_tmpl;
20798 tree spec;
20806 /* If this function is a clone, handle it specially. */
20808 {
20809 tree spec;
20810 tree clone;
20812 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
20813 DECL_CLONED_FUNCTION. */
20819 /* Look for the clone. */
20823 /* We should always have found the clone by now. */
20826 }
20831 /* Check to see if we already have this specialization. */
20835 /* targ_ptr only has the innermost template args, so add the outer ones
20836 from tmpl, which could be either a partial instantiation or gen_tmpl (in
20837 the case of a non-dependent call within a template definition). */
20838 targ_ptr = (add_outermost_template_args
20840 targ_ptr));
20842 /* It would be nice to avoid hashing here and then again in tsubst_decl,
20843 but it doesn't seem to be on the hot path. */
20847 || ((fndecl
20853 {
20855 {
20859 }
20861 }
20864 complain))
20867 /* We are building a FUNCTION_DECL, during which the access of its
20868 parameters and return types have to be checked. However this
20869 FUNCTION_DECL which is the desired context for access checking
20870 is not built yet. We solve this chicken-and-egg problem by
20871 deferring all checks until we have the FUNCTION_DECL. */
20874 /* Instantiation of the function happens in the context of the function
20875 template, not the context of the overload resolution we're doing. */
20877 /* If there are dependent arguments, e.g. because we're doing partial
20878 ordering, make sure processing_template_decl stays set. */
20882 {
20886 }
20892 {
20893 /* We need to determine if we're using a partial or explicit
20894 specialization now, because the type of the variable could be
20895 different. */
20901 {
20906 }
20907 }
20909 /* Substitute template parameters to obtain the specialization. */
20917 {
20920 }
20922 /* The DECL_TI_TEMPLATE should always be the immediate parent
20923 template, not the most general template. */
20927 /* Now we know the specialization, compute access previously
20928 deferred. Do no access control for inheriting constructors,
20929 as we already checked access for the inherited constructor. */
20932 {
20937 }
20940 /* If we've just instantiated the main entry point for a function,
20941 instantiate all the alternate entry points as well. We do this
20942 by cloning the instantiation of the main entry point, not by
20943 instantiating the template clones. */
20949 {
20951 {
20952 /* Remember to reinstantiate when we're out of SFINAE so the user
20953 can see the errors. */
20955 }
20957 }
20959 }
20961 /* Wrapper for instantiate_template_1. */
20963 tree
20965 {
20966 tree ret;
20971 }
20973 /* Instantiate the alias template TMPL with ARGS. Also push a template
20974 instantiation level, which instantiate_template doesn't do because
20975 functions and variables have sufficient context established by the
20976 callers. */
20978 static tree
20980 {
20984 args =
20990 /* FIXME check for satisfaction in check_instantiated_args. */
20994 {
20996 {
20997 auto_diagnostic_group d;
21000 }
21002 }
21010 }
21012 /* PARM is a template parameter pack for FN. Returns true iff
21013 PARM is used in a deducible way in the argument list of FN. */
21015 static bool
21017 {
21020 {
21022 tree packs;
21028 {
21029 /* The template parameter pack is used in a function parameter
21030 pack. If this is the end of the parameter list, the
21031 template parameter pack is deducible. */
21034 else
21035 /* Otherwise, not. Well, it could be deduced from
21036 a non-pack parameter, but doing so would end up with
21037 a deduction mismatch, so don't bother. */
21039 }
21040 }
21041 /* The template parameter pack isn't used in any function parameter
21042 packs, but it might be used deeper, e.g. tuple<Args...>. */
21044 }
21046 /* Subroutine of fn_type_unification: check non-dependent parms for
21047 convertibility. */
21049 static int
21053 {
21054 /* Non-constructor methods need to leave a conversion for 'this', which
21055 isn't included in nargs here. */
21061 {
21067 /* For a function parameter pack that occurs at the end of the
21068 parameter-declaration-list, the type A of each remaining
21069 argument of the call is compared with the type P of the
21070 declarator-id of the function parameter pack. */
21076 /* For a function parameter pack that does not occur at the
21077 end of the parameter-declaration-list, the type of the
21078 parameter pack is a non-deduced context. */
21082 {
21090 }
21093 }
21096 }
21098 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
21099 NARGS elements of the arguments that are being used when calling
21100 it. TARGS is a vector into which the deduced template arguments
21101 are placed.
21103 Returns either a FUNCTION_DECL for the matching specialization of FN or
21104 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
21105 true, diagnostics will be printed to explain why it failed.
21107 If FN is a conversion operator, or we are trying to produce a specific
21108 specialization, RETURN_TYPE is the return type desired.
21110 The EXPLICIT_TARGS are explicit template arguments provided via a
21111 template-id.
21113 The parameter STRICT is one of:
21115 DEDUCE_CALL:
21116 We are deducing arguments for a function call, as in
21117 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
21118 deducing arguments for a call to the result of a conversion
21119 function template, as in [over.call.object].
21121 DEDUCE_CONV:
21122 We are deducing arguments for a conversion function, as in
21123 [temp.deduct.conv].
21125 DEDUCE_EXACT:
21126 We are deducing arguments when doing an explicit instantiation
21127 as in [temp.explicit], when determining an explicit specialization
21128 as in [temp.expl.spec], or when taking the address of a function
21129 template, as in [temp.deduct.funcaddr]. */
21131 tree
21133 tree explicit_targs,
21134 tree targs,
21137 tree return_type,
21138 unification_kind_t strict,
21143 {
21144 tree parms;
21145 tree fntype;
21150 /* type_unification_real will pass back any access checks from default
21151 template argument substitution. */
21153 /* We don't have all the template args yet. */
21166 full_targs = (add_outermost_template_args
21168 targs));
21173 /* In C++0x, it's possible to have a function template whose type depends
21174 on itself recursively. This is most obvious with decltype, but can also
21175 occur with enumeration scope (c++/48969). So we need to catch infinite
21176 recursion and reject the substitution at deduction time; this function
21177 will return error_mark_node for any repeated substitution.
21179 This also catches excessive recursion such as when f<N> depends on
21180 f<N-1> across all integers, and returns error_mark_node for all the
21181 substitutions back up to the initial one.
21183 This is, of course, not reentrant. */
21192 {
21193 /* [temp.deduct]
21195 The specified template arguments must match the template
21196 parameters in kind (i.e., type, nontype, template), and there
21197 must not be more arguments than there are parameters;
21198 otherwise type deduction fails.
21200 Nontype arguments must match the types of the corresponding
21201 nontype template parameters, or must be convertible to the
21202 types of the corresponding nontype parameters as specified in
21203 _temp.arg.nontype_, otherwise type deduction fails.
21205 All references in the function type of the function template
21206 to the corresponding template parameters are replaced by the
21207 specified template argument values. If a substitution in a
21208 template parameter or in the function type of the function
21209 template results in an invalid type, type deduction fails. */
21220 explicit_targs);
21222 /* Adjust any explicit template arguments before entering the
21223 substitution context. */
21224 explicit_targs
21232 /* Substitute the explicit args into the function type. This is
21233 necessary so that, for instance, explicitly declared function
21234 arguments can match null pointed constants. If we were given
21235 an incomplete set of explicit args, we must not do semantic
21236 processing during substitution as we could create partial
21237 instantiations. */
21239 {
21244 /* Dig out the actual parm. */
21247 {
21250 }
21252 {
21255 }
21258 /* No explicit argument for this template parameter. */
21261 {
21262 /* Mark the argument pack as "incomplete". We could
21263 still deduce more arguments during unification.
21264 We remove this mark in type_unification_real. */
21269 /* We have some incomplete argument packs. */
21271 }
21272 }
21275 {
21277 {
21280 }
21283 /* Ignore any access checks; we'll see them again in
21284 instantiate_template and they might have the wrong
21285 access path at this point. */
21296 }
21298 /* Place the explicitly specified arguments in TARGS. */
21304 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
21306 }
21309 {
21315 }
21320 /* Never do unification on the 'this' parameter. */
21324 {
21325 /* We're deducing for a call to the result of a template conversion
21326 function. The parms we really want are in return_type. */
21330 }
21332 {
21334 }
21336 /* We allow incomplete unification without an error message here
21337 because the standard doesn't seem to explicitly prohibit it. Our
21338 callers must be ready to deal with unification failures in any
21339 event. */
21341 /* If we aren't explaining yet, push tinst context so we can see where
21342 any errors (e.g. from class instantiations triggered by instantiation
21343 of default template arguments) come from. If we are explaining, this
21344 context is redundant. */
21346 {
21349 }
21359 /* Now that we have bindings for all of the template arguments,
21360 ensure that the arguments deduced for the template template
21361 parameters have compatible template parameter lists. We cannot
21362 check this property before we have deduced all template
21363 arguments, because the template parameter types of a template
21364 template parameter might depend on prior template parameters
21365 deduced after the template template parameter. The following
21366 ill-formed example illustrates this issue:
21368 template<typename T, template<T> class C> void f(C<5>, T);
21370 template<int N> struct X {};
21372 void g() {
21373 f(X<5>(), 5l); // error: template argument deduction fails
21374 }
21376 The template parameter list of 'C' depends on the template type
21377 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
21378 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
21379 time that we deduce 'C'. */
21382 {
21385 }
21387 deduced:
21389 /* CWG2369: Check satisfaction before non-deducible conversions. */
21391 {
21395 }
21397 /* DR 1391: All parameters have args, now check non-dependent parms for
21398 convertibility. We don't do this if all args were explicitly specified,
21399 as the standard says that we substitute explicit args immediately. */
21405 /* All is well so far. Now, check:
21407 [temp.deduct]
21409 When all template arguments have been deduced, all uses of
21410 template parameters in nondeduced contexts are replaced with
21411 the corresponding deduced argument values. If the
21412 substitution results in an invalid type, as described above,
21413 type deduction fails. */
21415 {
21418 }
21420 /* Also collect access checks from the instantiation. */
21433 /* Now perform any access checks encountered during substitution. */
21440 /* If we're looking for an exact match, check that what we got
21441 is indeed an exact match. It might not be if some template
21442 parameters are used in non-deduced contexts. But don't check
21443 for an exact match if we have dependent template arguments;
21444 in that case we're doing partial ordering, and we already know
21445 that we have two candidates that will provide the actual type. */
21447 {
21451 tree sarg
21457 {
21461 }
21462 }
21464 /* After doing deduction with the inherited constructor, actually return an
21465 instantiation of the inheriting constructor. */
21471 fail:
21474 {
21476 /* Reset once we're all the way out. */
21478 }
21481 }
21483 /* Adjust types before performing type deduction, as described in
21484 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
21485 sections are symmetric. PARM is the type of a function parameter
21486 or the return type of the conversion function. ARG is the type of
21487 the argument passed to the call, or the type of the value
21488 initialized with the result of the conversion function.
21489 ARG_EXPR is the original argument expression, which may be null. */
21491 static int
21495 tree arg_expr)
21496 {
21500 {
21505 /* Swap PARM and ARG throughout the remainder of this
21506 function; the handling is precisely symmetric since PARM
21507 will initialize ARG rather than vice versa. */
21512 /* Core issue #873: Do the DR606 thing (see below) for these cases,
21513 too, but here handle it by stripping the reference from PARM
21514 rather than by adding it to ARG. */
21522 /* Nothing else to do in this case. */
21527 }
21530 {
21531 /* [temp.deduct.call]
21533 If P is not a reference type:
21535 --If A is an array type, the pointer type produced by the
21536 array-to-pointer standard conversion (_conv.array_) is
21537 used in place of A for type deduction; otherwise,
21539 --If A is a function type, the pointer type produced by
21540 the function-to-pointer standard conversion
21541 (_conv.func_) is used in place of A for type deduction;
21542 otherwise,
21544 --If A is a cv-qualified type, the top level
21545 cv-qualifiers of A's type are ignored for type
21546 deduction. */
21551 else
21553 }
21555 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
21556 reference to a cv-unqualified template parameter that does not represent a
21557 template parameter of a class template (during class template argument
21558 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
21559 an lvalue, the type "lvalue reference to A" is used in place of A for type
21560 deduction. */
21567 /* try_one_overload doesn't provide an arg_expr, but
21568 functions are always lvalues. */
21572 /* [temp.deduct.call]
21574 If P is a cv-qualified type, the top level cv-qualifiers
21575 of P's type are ignored for type deduction. If P is a
21576 reference type, the type referred to by P is used for
21577 type deduction. */
21580 {
21583 }
21585 /* DR 322. For conversion deduction, remove a reference type on parm
21586 too (which has been swapped into ARG). */
21591 }
21593 /* Subroutine of fn_type_unification. PARM is a function parameter of a
21594 template which doesn't contain any deducible template parameters; check if
21595 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
21596 unify_one_argument. */
21598 static int
21602 {
21603 tree type;
21607 else
21615 {
21618 }
21620 {
21624 /* Avoid recalculating this in add_function_candidate. */
21625 ok = (*conv_p
21627 else
21631 }
21635 else
21637 }
21641 /* Returns true iff the expression EXPR is one from which a template
21642 argument can be deduced. In other words, if it's an undecorated
21643 use of a template non-type parameter. */
21645 static bool
21647 {
21648 /* Strip implicit conversions. */
21652 }
21654 /* Returns true iff the array domain DOMAIN uses a template parameter in a
21655 deducible way; that is, if it has a max value of <PARM> - 1. */
21657 static bool
21659 {
21668 }
21670 /* Returns true iff the template arguments ARGS use a template parameter
21671 in a deducible way. */
21673 static bool
21675 {
21677 {
21682 else
21683 {
21690 else
21692 }
21695 }
21697 }
21699 /* Returns true iff TYPE contains any deducible references to template
21700 parameters, as per 14.8.2.5. */
21702 static bool
21704 {
21708 /* T
21709 cv-list T
21710 TT<T>
21711 TT<i>
21712 TT<> */
21717 /* T*
21718 T&
21719 T&& */
21723 /* T[integer-constant ]
21724 type [i] */
21729 /* T type ::*
21730 type T::*
21731 T T::*
21732 T (type ::*)()
21733 type (T::*)()
21734 type (type ::*)(T)
21735 type (T::*)(T)
21736 T (type ::*)(T)
21737 T (T::*)()
21738 T (T::*)(T) */
21741 || (uses_deducible_template_parms
21744 /* template-name <T> (where template-name refers to a class template)
21745 template-name <i> (where template-name refers to a class template) */
21752 /* type (T)
21753 T()
21754 T(T) */
21756 {
21765 }
21768 }
21770 /* Subroutine of type_unification_real and unify_pack_expansion to
21771 handle unification of a single P/A pair. Parameters are as
21772 for those functions. */
21774 static int
21778 {
21785 /* We can't deduce anything from this, but we might get all the
21786 template args from other function args. */
21789 /* Implicit conversions (Clause 4) will be performed on a function
21790 argument to convert it to the type of the corresponding function
21791 parameter if the parameter type contains no template-parameters that
21792 participate in template argument deduction. */
21795 /* For function parameters with no deducible template parameters,
21796 just return. We'll check non-dependent conversions later. */
21800 {
21802 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
21803 | UNIFY_ALLOW_MORE_CV_QUAL
21817 }
21819 /* We only do these transformations if this is the top-level
21820 parameter_type_list in a call or declaration matching; in other
21821 situations (nested function declarators, template argument lists) we
21822 won't be comparing a type to an expression, and we don't do any type
21823 adjustments. */
21825 {
21827 {
21830 {
21831 /* [temp.deduct.type] A template-argument can be
21832 deduced from a pointer to function or pointer
21833 to member function argument if the set of
21834 overloaded functions does not contain function
21835 templates and at most one of a set of
21836 overloaded functions provides a unique
21837 match. */
21841 /* If a unique match was not found, this is a
21842 non-deduced context, so we still succeed. */
21844 }
21850 }
21852 arg_strict |=
21854 }
21855 else
21860 /* For deduction from an init-list we need the actual list. */
21864 }
21866 /* for_each_template_parm callback that always returns 0. */
21868 static int
21870 {
21872 }
21874 /* for_each_template_parm any_fn callback to handle deduction of a template
21875 type argument from the type of an array bound. */
21877 static int
21879 {
21887 {
21893 }
21895 /* Keep walking. */
21897 }
21899 /* Try to deduce any not-yet-deduced template type arguments from the type of
21900 an array bound. This is handled separately from unify because 14.8.2.5 says
21901 "The type of a type parameter is only deduced from an array bound if it is
21902 not otherwise deduced." */
21904 static void
21906 {
21911 }
21913 /* Most parms like fn_type_unification.
21915 If SUBR is 1, we're being called recursively (to unify the
21916 arguments of a function or method parameter of a function
21917 template).
21919 CHECKS is a pointer to a vector of access checks encountered while
21920 substituting default template arguments. */
21922 static int
21924 tree full_targs,
21925 tree xparms,
21929 unification_kind_t strict,
21932 {
21937 tree parms;
21948 /* Reset the number of non-defaulted template arguments contained
21949 in TARGS. */
21952 again:
21960 {
21965 /* For a function parameter pack that occurs at the end of the
21966 parameter-declaration-list, the type A of each remaining
21967 argument of the call is compared with the type P of the
21968 declarator-id of the function parameter pack. */
21974 /* For a function parameter pack that does not occur at the
21975 end of the parameter-declaration-list, the type of the
21976 parameter pack is a non-deduced context. */
21983 explain_p))
21985 }
21990 {
21991 /* Unify the remaining arguments with the pack expansion type. */
21992 tree argvec;
21995 /* Allocate a TREE_VEC and copy in all of the arguments */
22000 /* Copy the parameter into parmvec. */
22006 /* Advance to the end of the list of parameters. */
22008 }
22010 /* Fail if we've reached the end of the parm list, and more args
22011 are present, and the parm list isn't variadic. */
22014 /* Fail if parms are left and they don't have default values and
22015 they aren't all deduced as empty packs (c++/57397). This is
22016 consistent with sufficient_parms_p. */
22019 {
22023 do
22024 {
22027 count++;
22029 }
22033 type_pack_p);
22034 }
22037 {
22038 tsubst_flags_t complain = (explain_p
22039 ? tf_warning_or_error
22044 {
22048 /* Clear the "incomplete" flags on all argument packs now so that
22049 substituting them into later default arguments works. */
22051 {
22054 }
22062 {
22067 }
22069 /* If this is an undeduced nontype parameter that depends on
22070 a type parameter, try another pass; its type may have been
22071 deduced from a later argument than the one from which
22072 this parameter can be deduced. */
22076 {
22079 }
22081 /* Core issue #226 (C++0x) [temp.deduct]:
22083 If a template argument has not been deduced, its
22084 default template argument, if any, is used.
22086 When we are in C++98 mode, TREE_PURPOSE will either
22087 be NULL_TREE or ERROR_MARK_NODE, so we do not need
22088 to explicitly check cxx_dialect here. */
22090 /* OK, there is a default argument. Wait until after the
22091 conversion check to do substitution. */
22094 /* If the type parameter is a parameter pack, then it will
22095 be deduced to an empty parameter pack. */
22097 {
22098 tree arg;
22101 {
22104 }
22105 else
22112 }
22115 }
22117 /* Now substitute into the default template arguments. */
22119 {
22135 {
22136 /* The type of this non-type parameter depends on undeduced
22137 parameters. Don't try to use its default argument yet,
22138 since we might deduce an argument for it on the next pass,
22139 but do check whether the arguments we already have cause
22140 substitution failure, so that that happens before we try
22141 later default arguments (78489). */
22144 NULL_TREE);
22148 else
22150 }
22151 else
22152 {
22153 /* Even if the call is happening in template context, getting
22154 here means it's non-dependent, and a default argument is
22155 considered a separate definition under [temp.decls], so we can
22156 do this substitution without processing_template_decl. This
22157 is important if the default argument contains something that
22158 might be instantiation-dependent like access (87480). */
22159 processing_template_decl_sentinel s;
22162 {
22163 /* First instatiate in template context, in case we still
22164 depend on undeduced template parameters. */
22167 NULL_TREE);
22171 /* We replaced all the tparms, substitute again out of
22172 template context. */
22174 }
22177 NULL_TREE);
22184 else
22186 }
22195 {
22197 /* The position of the first default template argument,
22198 is also the number of non-defaulted arguments in TARGS.
22199 Record that. */
22202 }
22203 }
22207 }
22213 }
22215 /* Subroutine of type_unification_real. Args are like the variables
22216 at the call site. ARG is an overloaded function (or template-id);
22217 we try deducing template args from each of the overloads, and if
22218 only one succeeds, we go with that. Modifies TARGS and returns
22219 true on success. */
22221 static bool
22223 tree targs,
22224 tree parm,
22225 tree arg,
22226 unification_kind_t strict,
22229 {
22236 {
22239 }
22240 else
22244 /* Handle `&x' where `x' is some static or non-static member
22245 function name. */
22251 /* Strip baselink information. */
22256 {
22257 /* If we got some explicit template args, we need to plug them into
22258 the affected templates before we try to unify, in case the
22259 explicit args will completely resolve the templates in question. */
22266 {
22279 {
22284 {
22285 /* Instantiate the function to deduce its return type. */
22289 }
22295 {
22298 }
22299 }
22302 }
22303 /* If no templates (or more than one) are fully resolved by the
22304 explicit arguments, this template-id is a non-deduced context; it
22305 could still be OK if we deduce all template arguments for the
22306 enclosing call through other arguments. */
22309 }
22311 /* If ARG is, for example, "(0, &f)" then its type will be unknown
22312 -- but the deduction does not succeed because the expression is
22313 not just the function on its own. */
22315 else
22317 {
22322 {
22325 }
22326 }
22328 /* [temp.deduct.type] A template-argument can be deduced from a pointer
22329 to function or pointer to member function argument if the set of
22330 overloaded functions does not contain function templates and at most
22331 one of a set of overloaded functions provides a unique match.
22333 So if we found multiple possibilities, we return success but don't
22334 deduce anything. */
22337 {
22341 {
22346 /* Don't forget explicit template arguments in a pack. */
22350 }
22351 }
22356 }
22358 /* Core DR 115: In contexts where deduction is done and fails, or in
22359 contexts where deduction is not done, if a template argument list is
22360 specified and it, along with any default template arguments, identifies
22361 a single function template specialization, then the template-id is an
22362 lvalue for the function template specialization. */
22364 tree
22366 {
22379 {
22382 }
22384 {
22387 }
22389 {
22392 }
22395 {
22399 /* If we got some explicit template args, we need to plug them into
22400 the affected templates before we try to unify, in case the
22401 explicit args will completely resolve the templates in question. */
22409 {
22422 {
22425 {
22428 }
22431 {
22434 }
22435 }
22436 }
22438 {
22446 {
22447 tree base
22450 }
22454 }
22456 /* There were no good options and at least one bad one, so let the
22457 user know what the problem is. */
22459 }
22461 }
22463 /* As above, but error out if the expression remains overloaded. */
22465 tree
22467 {
22470 {
22474 }
22476 }
22478 /* Subroutine of resolve_overloaded_unification; does deduction for a single
22479 overload. Fills TARGS with any deduced arguments, or error_mark_node if
22480 different overloads deduce different arguments for a given parm.
22481 ADDR_P is true if the expression for which deduction is being
22482 performed was of the form "& fn" rather than simply "fn".
22484 Returns 1 on success. */
22486 static int
22488 tree orig_targs,
22489 tree targs,
22490 tree parm,
22491 tree arg,
22492 unification_kind_t strict,
22496 {
22498 tree tempargs;
22504 /* [temp.deduct.type] A template-argument can be deduced from a pointer
22505 to function or pointer to member function argument if the set of
22506 overloaded functions does not contain function templates and at most
22507 one of a set of overloaded functions provides a unique match.
22509 So if this is a template, just return success. */
22521 /* We don't copy orig_targs for this because if we have already deduced
22522 some template args from previous args, unify would complain when we
22523 try to deduce a template parameter for the same argument, even though
22524 there isn't really a conflict. */
22531 /* First make sure we didn't deduce anything that conflicts with
22532 explicitly specified args. */
22534 {
22541 /* Since we're unifying against ourselves, we will fill in
22542 template args used in the function parm list with our own
22543 template parms. Discard them. */
22546 {
22547 /* Check that the argument at each index of the deduced argument pack
22548 is equivalent to the corresponding explicitly specified argument.
22549 We may have deduced more arguments than were explicitly specified,
22550 and that's OK. */
22552 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
22553 that's wrong if we deduce the same argument pack from multiple
22554 function arguments: it's only incomplete the first time. */
22567 }
22570 }
22573 {
22578 }
22581 }
22583 /* PARM is a template class (perhaps with unbound template
22584 parameters). ARG is a fully instantiated type. If ARG can be
22585 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
22586 TARGS are as for unify. */
22588 static tree
22591 {
22592 tree copy_of_targs;
22602 /* We need to make a new template argument vector for the call to
22603 unify. If we used TARGS, we'd clutter it up with the result of
22604 the attempted unification, even if this class didn't work out.
22605 We also don't want to commit ourselves to all the unifications
22606 we've already done, since unification is supposed to be done on
22607 an argument-by-argument basis. In other words, consider the
22608 following pathological case:
22610 template <int I, int J, int K>
22611 struct S {};
22613 template <int I, int J>
22614 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
22616 template <int I, int J, int K>
22617 void f(S<I, J, K>, S<I, I, I>);
22619 void g() {
22620 S<0, 0, 0> s0;
22621 S<0, 1, 2> s2;
22623 f(s0, s2);
22624 }
22626 Now, by the time we consider the unification involving `s2', we
22627 already know that we must have `f<0, 0, 0>'. But, even though
22628 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
22629 because there are two ways to unify base classes of S<0, 1, 2>
22630 with S<I, I, I>. If we kept the already deduced knowledge, we
22631 would reject the possibility I=1. */
22635 {
22639 }
22641 /* If unification failed, we're done. */
22647 }
22649 /* Given a template type PARM and a class type ARG, find the unique
22650 base type in ARG that is an instance of PARM. We do not examine
22651 ARG itself; only its base-classes. If there is not exactly one
22652 appropriate base class, return NULL_TREE. PARM may be the type of
22653 a partial specialization, as well as a plain template type. Used
22654 by unify. */
22656 static enum template_base_result
22659 {
22661 tree binfo;
22667 {
22668 /* The type could not be completed. */
22671 }
22673 /* Walk in inheritance graph order. The search order is not
22674 important, and this avoids multiple walks of virtual bases. */
22676 {
22681 {
22682 /* If there is more than one satisfactory baseclass, then:
22684 [temp.deduct.call]
22686 If they yield more than one possible deduced A, the type
22687 deduction fails.
22689 applies. */
22691 {
22692 /* [temp.deduct.call]/4.3: If there is a class C that is a
22693 (direct or indirect) base class of D and derived (directly or
22694 indirectly) from a class B and that would be a valid deduced
22695 A, the deduced A cannot be B or pointer to B, respectively. */
22697 /* Ignore r. */
22701 else
22702 {
22705 }
22706 }
22709 }
22710 }
22714 }
22716 /* Returns the level of DECL, which declares a template parameter. */
22718 static int
22720 {
22722 {
22732 }
22734 }
22736 /* Decide whether ARG can be unified with PARM, considering only the
22737 cv-qualifiers of each type, given STRICT as documented for unify.
22738 Returns nonzero iff the unification is OK on that basis. */
22740 static int
22742 {
22748 {
22749 /* Although a CVR qualifier is ignored when being applied to a
22750 substituted template parameter ([8.3.2]/1 for example), that
22751 does not allow us to unify "const T" with "int&" because both
22752 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
22753 It is ok when we're allowing additional CV qualifiers
22754 at the outer level [14.8.2.1]/3,1st bullet. */
22763 }
22774 }
22776 /* Determines the LEVEL and INDEX for the template parameter PARM. */
22777 void
22779 {
22783 {
22786 }
22787 else
22788 {
22791 }
22792 }
22794 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
22795 do { \
22796 if (unify (TP, TA, P, A, S, EP)) \
22797 return 1; \
22798 } while (0)
22800 /* Unifies the remaining arguments in PACKED_ARGS with the pack
22801 expansion at the end of PACKED_PARMS. Returns 0 if the type
22802 deduction succeeds, 1 otherwise. STRICT is the same as in
22803 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
22804 function call argument list. We'll need to adjust the arguments to make them
22805 types. SUBR tells us if this is from a recursive call to
22806 type_unification_real, or for comparing two template argument
22807 lists. */
22809 static int
22813 {
22814 tree parm
22820 /* Add in any args remembered from an earlier partial instantiation. */
22828 /* Determine the parameter packs we will be deducing from the
22829 pattern, and record their current deductions. */
22832 {
22836 /* Only template parameter packs can be deduced, not e.g. function
22837 parameter packs or __bases or __integer_pack. */
22841 /* Determine the index and level of this parameter pack. */
22846 /* Keep track of the parameter packs and their corresponding
22847 argument packs. */
22850 }
22852 /* Loop through all of the arguments that have not yet been
22853 unified and unify each with the pattern. */
22855 {
22856 tree parm;
22860 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
22861 or the element of its argument pack at the current index if
22862 this argument was explicitly specified. */
22864 {
22873 {
22876 }
22878 }
22880 /* If we had explicit template arguments, substitute them into the
22881 pattern before deduction. */
22883 {
22884 /* Some arguments might still be unspecified or dependent. */
22892 NULL_TREE);
22897 }
22898 else
22901 /* Unify the pattern with the current argument. */
22903 explain_p))
22906 /* For each parameter pack, collect the deduced value. */
22908 {
22914 }
22915 }
22917 /* Verify that the results of unification with the parameter packs
22918 produce results consistent with what we've seen before, and make
22919 the deduced argument packs available. */
22921 {
22928 /* By default keep the original deduced argument pack.
22929 If necessary, more specific code is going to update the
22930 resulting deduced argument later down in this function. */
22934 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
22935 actually deduce anything. */
22943 {
22944 /* If we had fewer function args than explicit template args,
22945 just use the explicits. */
22950 }
22953 {
22954 tree result;
22955 /* Build the deduced *_ARGUMENT_PACK. */
22957 {
22960 }
22961 else
22966 /* Note the deduced argument packs for this parameter
22967 pack. */
22969 }
22973 {
22974 /* We only had the explicitly-provided arguments before, but
22975 now we have a complete set of arguments. */
22981 }
22982 else
22983 {
22987 /* During template argument deduction for the aggregate deduction
22988 candidate, the number of elements in a trailing parameter pack
22989 is only deduced from the number of remaining function
22990 arguments if it is not otherwise deduced. */
22997 /* Inconsistent unification of this parameter pack. */
22999 bad_old_arg,
23000 bad_new_arg);
23001 }
23002 }
23005 }
23007 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
23008 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
23009 parameters and return value are as for unify. */
23011 static int
23015 {
23016 tree parm_max;
23017 tree arg_max;
23021 /* Our representation of array types uses "N - 1" as the
23022 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
23023 not an integer constant. We cannot unify arbitrarily
23024 complex expressions, so we eliminate the MINUS_EXPRs
23025 here. */
23029 {
23032 }
23036 {
23037 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
23038 trying to unify the type of a variable with the type
23039 of a template parameter. For example:
23041 template <unsigned int N>
23042 void f (char (&) [N]);
23043 int g();
23044 void h(int i) {
23045 char a[g(i)];
23046 f(a);
23047 }
23049 Here, the type of the ARG will be "int [g(i)]", and
23050 may be a SAVE_EXPR, etc. */
23054 }
23056 /* If only one of the bounds used a MINUS_EXPR, compensate
23057 by adding one to the other bound. */
23060 integer_type_node,
23061 parm_max,
23062 integer_one_node);
23065 integer_type_node,
23066 arg_max,
23067 integer_one_node);
23071 }
23073 /* Returns whether T, a P or A in unify, is a type, template or expression. */
23077 static pa_kind_t
23079 {
23088 else
23090 }
23092 /* Deduce the value of template parameters. TPARMS is the (innermost)
23093 set of template parameters to a template. TARGS is the bindings
23094 for those template parameters, as determined thus far; TARGS may
23095 include template arguments for outer levels of template parameters
23096 as well. PARM is a parameter to a template function, or a
23097 subcomponent of that parameter; ARG is the corresponding argument.
23098 This function attempts to match PARM with ARG in a manner
23099 consistent with the existing assignments in TARGS. If more values
23100 are deduced, then TARGS is updated.
23102 Returns 0 if the type deduction succeeds, 1 otherwise. The
23103 parameter STRICT is a bitwise or of the following flags:
23105 UNIFY_ALLOW_NONE:
23106 Require an exact match between PARM and ARG.
23107 UNIFY_ALLOW_MORE_CV_QUAL:
23108 Allow the deduced ARG to be more cv-qualified (by qualification
23109 conversion) than ARG.
23110 UNIFY_ALLOW_LESS_CV_QUAL:
23111 Allow the deduced ARG to be less cv-qualified than ARG.
23112 UNIFY_ALLOW_DERIVED:
23113 Allow the deduced ARG to be a template base class of ARG,
23114 or a pointer to a template base class of the type pointed to by
23115 ARG.
23116 UNIFY_ALLOW_INTEGER:
23117 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
23118 case for more information.
23119 UNIFY_ALLOW_OUTER_LEVEL:
23120 This is the outermost level of a deduction. Used to determine validity
23121 of qualification conversions. A valid qualification conversion must
23122 have const qualified pointers leading up to the inner type which
23123 requires additional CV quals, except at the outer level, where const
23124 is not required [conv.qual]. It would be normal to set this flag in
23125 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
23126 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
23127 This is the outermost level of a deduction, and PARM can be more CV
23128 qualified at this point.
23129 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
23130 This is the outermost level of a deduction, and PARM can be less CV
23131 qualified at this point. */
23133 static int
23136 {
23138 tree targ;
23139 tree tparm;
23141 tsubst_flags_t complain = (explain_p
23142 ? tf_warning_or_error
23145 /* I don't think this will do the right thing with respect to types.
23146 But the only case I've seen it in so far has been array bounds, where
23147 signedness is the only information lost, and I think that will be
23148 okay. VIEW_CONVERT_EXPR can appear with class NTTP, thanks to
23149 finish_id_expression_1, and are also OK. */
23157 /* We can't deduce anything from this, but we might get all the
23158 template args from other function args. */
23164 /* If PARM uses template parameters, then we can't bail out here,
23165 even if ARG == PARM, since we won't record unifications for the
23166 template parameters. We might need them if we're trying to
23167 figure out which of two things is more specialized. */
23171 /* Handle init lists early, so the rest of the function can assume
23172 we're dealing with a type. */
23174 {
23181 /* We can only deduce from an initializer list argument if the
23182 parameter is std::initializer_list or an array; otherwise this
23183 is a non-deduced context. */
23188 else
23189 {
23191 /* Deduction is defined in terms of a single type, so just punt
23192 on the (bizarre) std::initializer_list<T...>. */
23195 }
23200 /* If ELTTYPE has no deducible template parms, skip deduction from
23202 else
23204 {
23211 {
23215 /* It should only be possible to get here for a call. */
23217 elt_strict |= maybe_adjust_types_for_deduction
23220 }
23223 explain_p);
23224 }
23228 {
23229 /* Also deduce from the length of the initializer list. */
23236 }
23238 /* If the std::initializer_list<T> deduction worked, replace the
23239 deduced A with std::initializer_list<A>. */
23241 {
23246 }
23248 }
23250 /* If parm and arg aren't the same kind of thing (template, type, or
23251 expression), fail early. */
23255 /* Immediately reject some pairs that won't unify because of
23256 cv-qualification mismatches. */
23259 /* It is the elements of the array which hold the cv quals of an array
23260 type, and the elements might be template type parms. We'll check
23261 when we recurse. */
23263 /* We check the cv-qualifiers when unifying with template type
23264 parameters below. We want to allow ARG `const T' to unify with
23265 PARM `T' for example, when computing which of two templates
23266 is more specialized, for example. */
23280 {
23284 /* In a type which contains a nested-name-specifier, template
23285 argument values cannot be deduced for template parameters used
23286 within the nested-name-specifier. */
23298 /* The PARM is not one we're trying to unify. Just check
23299 to see if it matches ARG. */
23300 {
23305 else
23307 }
23314 /* Check for mixed types and values. */
23322 {
23325 {
23326 /* First try to match ARG directly. */
23328 explain_p);
23330 {
23331 /* Otherwise, look for a suitable base of ARG, as below. */
23338 }
23339 }
23340 /* ARG must be constructed from a template class or a template
23341 template parameter. */
23346 /* Deduce arguments T, i from TT<T> or TT<i>. */
23352 /* Fall through to deduce template name. */
23353 }
23357 {
23358 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
23360 /* Simple cases: Value already set, does match or doesn't. */
23365 }
23366 else
23367 {
23368 /* If PARM is `const T' and ARG is only `int', we don't have
23369 a match unless we are allowing additional qualification.
23370 If ARG is `const int' and PARM is just `T' that's OK;
23371 that binds `const int' to `T'. */
23376 /* Consider the case where ARG is `const volatile int' and
23377 PARM is `const T'. Then, T should be `volatile int'. */
23378 arg = cp_build_qualified_type_real
23383 /* Simple cases: Value already set, does match or doesn't. */
23389 /* Make sure that ARG is not a variable-sized array. (Note
23390 that were talking about variable-sized arrays (like
23391 `int[n]'), rather than arrays of unknown size (like
23392 `int[]').) We'll get very confused by such a type since
23393 the bound of the array is not constant, and therefore
23394 not mangleable. Besides, such types are not allowed in
23395 ISO C++, so we can do as we please here. We do allow
23396 them for 'auto' deduction, since that isn't ABI-exposed. */
23400 /* Strip typedefs as in convert_template_argument. */
23402 }
23404 /* If ARG is a parameter pack or an expansion, we cannot unify
23405 against it unless PARM is also a parameter pack. */
23410 /* If the argument deduction results is a METHOD_TYPE,
23411 then there is a problem.
23412 METHOD_TYPE doesn't map to any real C++ type the result of
23413 the deduction cannot be of that type. */
23427 {
23428 /* The PARM is not one we're trying to unify. Just check
23429 to see if it matches ARG. */
23435 }
23441 {
23445 /* We're deducing from an array bound, the type doesn't matter. */
23451 }
23453 /* [temp.deduct.type] If, in the declaration of a function template
23454 with a non-type template-parameter, the non-type
23455 template-parameter is used in an expression in the function
23456 parameter-list and, if the corresponding template-argument is
23457 deduced, the template-argument type shall match the type of the
23458 template-parameter exactly, except that a template-argument
23459 deduced from an array bound may be of any integral type.
23460 The non-type parameter might use already deduced type parameters. */
23463 /* We don't have enough levels of args to do any substitution. This
23465 else
23466 {
23472 {
23476 }
23477 }
23480 /* Template-parameter dependent expression. Just accept it for now.
23481 It will later be processed in convert_template_argument. */
23482 ;
23486 /* OK. Ignore top-level quals here because a class-type template
23490 /* Convert the ARG to the type of PARM; the deduced non-type
23491 template argument must exactly match the types of the
23492 corresponding parameter. */
23495 {
23496 /* We haven't deduced the type of this parameter yet. */
23498 /* We deduce from array bounds in try_array_deduction. */
23500 {
23501 /* Deduce it from the non-type argument. */
23506 }
23507 else
23508 /* Try again later. */
23510 }
23511 else
23514 /* If ARG is a parameter pack or an expansion, we cannot unify
23515 against it unless PARM is also a parameter pack. */
23520 {
23523 }
23528 {
23529 /* A pointer-to-member constant can be unified only with
23530 another constant. */
23534 /* Just unify the class member. It would be useless (and possibly
23535 wrong, depending on the strict flags) to unify also
23536 PTRMEM_CST_CLASS, because we want to be sure that both parm and
23537 arg refer to the same variable, even if through different
23538 classes. For instance:
23540 struct A { int x; };
23541 struct B : A { };
23543 Unification of &A::x and &B::x must succeed. */
23546 }
23549 {
23553 /* [temp.deduct.call]
23555 A can be another pointer or pointer to member type that can
23556 be converted to the deduced A via a qualification
23557 conversion (_conv.qual_).
23559 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
23560 This will allow for additional cv-qualification of the
23561 pointed-to types if appropriate. */
23564 /* The derived-to-base conversion only persists through one
23565 level of pointers. */
23570 }
23602 /* We have already checked cv-qualification at the top of the
23603 function. */
23607 /* As far as unification is concerned, this wins. Later checks
23608 will invalidate it if necessary. */
23611 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
23612 /* Type INTEGER_CST can come from ordinary constant template args. */
23624 {
23634 /* Check for pack expansions in the parameters. */
23636 {
23638 {
23640 /* We can unify against something with a trailing
23641 parameter pack. */
23643 else
23644 /* [temp.deduct.type]/9: If the template argument list of
23645 P contains a pack expansion that is not the last
23646 template argument, the entire template argument list
23647 is a non-deduced context. */
23649 }
23650 }
23652 /* If we don't have enough arguments to satisfy the parameters
23653 (not counting the pack expression at the end), or we have
23654 too many arguments for a parameter list that doesn't end in
23655 a pack expression, we can't unify. */
23661 /* Unify all of the parameters that precede the (optional)
23662 pack expression. */
23664 {
23669 }
23672 DEDUCE_EXACT,
23675 }
23683 {
23691 }
23696 {
23700 {
23701 /* First, we try to unify the PARM and ARG directly. */
23706 {
23707 /* Fallback to the special case allowed in
23708 [temp.deduct.call]:
23710 If P is a class, and P has the form
23711 template-id, then A can be a derived class of
23712 the deduced A. Likewise, if P is a pointer to
23713 a class of the form template-id, A can be a
23714 pointer to a derived class pointed to by the
23715 deduced A. */
23721 {
23722 /* Don't give the derived diagnostic if we're
23723 already dealing with the same template. */
23724 bool same_template
23730 }
23731 }
23732 }
23736 /* Perhaps PARM is something like S<U> and ARG is S<int>.
23737 Then, we should unify `int' and `U'. */
23739 else
23740 /* There's no chance of unification succeeding. */
23745 }
23752 {
23755 tree a;
23761 /* CV qualifications for methods can never be deduced, they must
23762 match exactly. We need to check them explicitly here,
23763 because type_unification_real treats them as any other
23764 cv-qualified parameter. */
23766 && (!check_cv_quals_for_unify
23794 {
23806 }
23809 }
23812 /* Unify a pointer to member with a pointer to member function, which
23813 deduces the type of the member as a function type. */
23815 {
23816 /* Check top-level cv qualifiers */
23824 /* Determine the type of the function we are unifying against. */
23828 }
23847 /* Matched cases are handled by the ARG == PARM test above. */
23851 /* We might get a variable as a non-type template argument in parm if the
23852 corresponding parameter is type-dependent. Make any necessary
23853 adjustments based on whether arg is a reference. */
23857 {
23862 }
23863 /* Now use the normal expression code to check whether they match. */
23874 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
23875 or UNDERLYING_TYPE nodes. */
23879 /* Unification fails if we hit an error node. */
23884 {
23894 }
23895 /* FALLTHRU */
23898 /* An unresolved overload is a nondeduced context. */
23904 expr:
23905 /* We must be looking at an expression. This can happen with
23906 something like:
23908 template <int I>
23909 void foo(S<I>, S<I + 2>);
23911 or
23913 template<typename T>
23914 void foo(A<T, T{}>);
23916 This is a "non-deduced context":
23918 [deduct.type]
23920 The non-deduced contexts are:
23922 --A non-type template argument or an array bound in which
23923 a subexpression references a template parameter.
23925 In these cases, we assume deduction succeeded, but don't
23926 actually infer any unifications. */
23931 else
23933 }
23934 }
23935 #undef RECUR_AND_CHECK_FAILURE
23936 \f
23937 /* Note that DECL can be defined in this translation unit, if
23938 required. */
23940 static void
23942 {
23943 tree clone;
23947 }
23949 /* Called if RESULT is explicitly instantiated, or is a member of an
23950 explicitly instantiated class. */
23952 void
23954 {
23957 /* If this entity has already been written out, it's too late to
23958 make any modifications. */
23962 /* For anonymous namespace we don't need to do anything. */
23964 {
23967 }
23970 /* The TREE_PUBLIC flag for function declarations will have been
23971 set correctly by tsubst. */
23974 /* This might have been set by an earlier implicit instantiation. */
23979 else
23980 {
23983 /* Always make artificials weak. */
23986 /* For WIN32 we also want to put explicit instantiations in
23987 linkonce sections. */
23992 /* If the function has already been instantiated, clear DECL_EXTERNAL,
23993 since start_preparsed_function wouldn't have if we had an earlier
23994 extern explicit instantiation. */
23996 }
23998 /* If EXTERN_P, then this function will not be emitted -- unless
23999 followed by an explicit instantiation, at which point its linkage
24000 will be adjusted. If !EXTERN_P, then this function will be
24001 emitted here. In neither circumstance do we want
24002 import_export_decl to adjust the linkage. */
24004 }
24006 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
24007 important template arguments. If any are missing, we check whether
24008 they're important by using error_mark_node for substituting into any
24009 args that were used for partial ordering (the ones between ARGS and END)
24010 and seeing if it bubbles up. */
24012 static bool
24014 {
24019 {
24022 }
24024 {
24028 }
24030 }
24032 /* Given two function templates PAT1 and PAT2, return:
24034 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
24035 -1 if PAT2 is more specialized than PAT1.
24036 0 if neither is more specialized.
24038 LEN indicates the number of parameters we should consider
24039 (defaulted parameters should not be considered).
24041 The 1998 std underspecified function template partial ordering, and
24042 DR214 addresses the issue. We take pairs of arguments, one from
24043 each of the templates, and deduce them against each other. One of
24044 the templates will be more specialized if all the *other*
24045 template's arguments deduce against its arguments and at least one
24046 of its arguments *does* *not* deduce against the other template's
24047 corresponding argument. Deduction is done as for class templates.
24048 The arguments used in deduction have reference and top level cv
24049 qualifiers removed. Iff both arguments were originally reference
24050 types *and* deduction succeeds in both directions, an lvalue reference
24051 wins against an rvalue reference and otherwise the template
24052 with the more cv-qualified argument wins for that pairing (if
24053 neither is more cv-qualified, they both are equal). Unlike regular
24054 deduction, after all the arguments have been deduced in this way,
24055 we do *not* verify the deduced template argument values can be
24056 substituted into non-deduced contexts.
24058 The logic can be a bit confusing here, because we look at deduce1 and
24059 targs1 to see if pat2 is at least as specialized, and vice versa; if we
24060 can find template arguments for pat1 to make arg1 look like arg2, that
24061 means that arg2 is at least as specialized as arg1. */
24063 int
24065 {
24078 /* Remove the this parameter from non-static member functions. If
24079 one is a non-static member function and the other is not a static
24080 member function, remove the first parameter from that function
24081 also. This situation occurs for operator functions where we
24082 locate both a member function (with this pointer) and non-member
24083 operator (with explicit first operand). */
24085 {
24090 }
24092 {
24095 {
24096 len--;
24098 }
24099 }
24101 /* If only one is a conversion operator, they are unordered. */
24105 /* Consider the return type for a conversion function */
24107 {
24110 len++;
24111 }
24113 processing_template_decl++;
24119 /* Stop when an ellipsis is seen. */
24121 {
24132 {
24133 /* When both arguments are pack expansions, we need only
24134 unify the patterns themselves. */
24138 /* This is the last comparison we need to do. */
24140 }
24143 {
24147 }
24150 {
24154 }
24160 {
24166 /* Setup the parameter vector, which contains only ARG1. */
24169 /* Setup the argument vector, which contains the remaining
24170 arguments. */
24179 /* We cannot deduce in the other direction, because ARG1 is
24180 a pack expansion but ARG2 is not. */
24182 }
24184 {
24190 /* Setup the parameter vector, which contains only ARG1. */
24193 /* Setup the argument vector, which contains the remaining
24194 arguments. */
24203 /* We cannot deduce in the other direction, because ARG2 is
24204 a pack expansion but ARG1 is not.*/
24206 }
24208 else
24209 {
24210 /* The normal case, where neither argument is a pack
24211 expansion. */
24218 }
24220 /* If we couldn't deduce arguments for tparms1 to make arg1 match
24221 arg2, then arg2 is not as specialized as arg1. */
24227 /* "If, for a given type, deduction succeeds in both directions
24228 (i.e., the types are identical after the transformations above)
24229 and both P and A were reference types (before being replaced with
24230 the type referred to above):
24231 - if the type from the argument template was an lvalue reference and
24232 the type from the parameter template was not, the argument type is
24233 considered to be more specialized than the other; otherwise,
24234 - if the type from the argument template is more cv-qualified
24235 than the type from the parameter template (as described above),
24236 the argument type is considered to be more specialized than the other;
24237 otherwise,
24238 - neither type is more specialized than the other." */
24241 {
24243 {
24246 else
24248 }
24250 {
24255 }
24256 }
24259 /* We've failed to deduce something in either direction.
24260 These must be unordered. */
24265 /* We have already processed all of the arguments in our
24266 handing of the pack expansion type. */
24271 }
24273 /* "In most cases, all template parameters must have values in order for
24274 deduction to succeed, but for partial ordering purposes a template
24275 parameter may remain without a value provided it is not used in the
24276 types being used for partial ordering."
24278 Thus, if we are missing any of the targs1 we need to substitute into
24279 origs1, then pat2 is not as specialized as pat1. This can happen when
24280 there is a nondeduced context. */
24286 processing_template_decl--;
24288 /* If both deductions succeed, the partial ordering selects the more
24289 constrained template. */
24290 /* P2113: If the corresponding template-parameters of the
24291 template-parameter-lists are not equivalent ([temp.over.link]) or if
24292 the function parameters that positionally correspond between the two
24293 templates are not of the same type, neither template is more
24294 specialized than the other. */
24299 {
24305 }
24307 /* All things being equal, if the next argument is a pack expansion
24308 for one function but not for the other, prefer the
24309 non-variadic function. FIXME this is bogus; see c++/41958. */
24313 {
24316 }
24322 else
24324 }
24326 /* Determine which of two partial specializations of TMPL is more
24327 specialized.
24329 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
24330 to the first partial specialization. The TREE_PURPOSE is the
24331 innermost set of template parameters for the partial
24332 specialization. PAT2 is similar, but for the second template.
24334 Return 1 if the first partial specialization is more specialized;
24335 -1 if the second is more specialized; 0 if neither is more
24336 specialized.
24338 See [temp.class.order] for information about determining which of
24339 two templates is more specialized. */
24341 static int
24343 {
24344 tree targs;
24353 /* Just like what happens for functions, if we are ordering between
24354 different template specializations, we may encounter dependent
24355 types in the arguments, and we need our dependency check functions
24356 to behave correctly. */
24360 {
24363 }
24367 {
24370 }
24373 /* If both deductions succeed, the partial ordering selects the more
24374 constrained template. */
24378 /* In the case of a tie where at least one of the templates
24379 has a parameter pack at the end, the template with the most
24380 non-packed parameters wins. */
24382 && any_deductions
24385 {
24391 /* We don't count the pack expansion at the end. */
24401 }
24404 }
24406 /* Return the template arguments that will produce the function signature
24407 DECL from the function template FN, with the explicit template
24408 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
24409 also match. Return NULL_TREE if no satisfactory arguments could be
24410 found. */
24412 static tree
24414 {
24418 tree decl_arg_types;
24421 tree arg;
24425 /* Never do unification on the 'this' parameter. */
24447 }
24449 /* Return the innermost template arguments that, when applied to a partial
24450 specialization SPEC_TMPL of TMPL, yield the ARGS.
24452 For example, suppose we have:
24454 template <class T, class U> struct S {};
24455 template <class T> struct S<T*, int> {};
24457 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
24458 partial specialization and the ARGS will be {double*, int}. The resulting
24459 vector will be {double}, indicating that `T' is bound to `double'. */
24461 static tree
24463 {
24465 tree spec_args
24468 tree deduced_args;
24469 tree innermost_deduced_args;
24473 {
24477 innermost_deduced_args);
24478 }
24479 else
24483 again:
24492 {
24494 {
24500 }
24502 }
24505 {
24508 }
24510 /* Verify that nondeduced template arguments agree with the type
24511 obtained from argument deduction.
24513 For example:
24515 struct A { typedef int X; };
24516 template <class T, class U> struct C {};
24517 template <class T> struct C<T, typename T::X> {};
24519 Then with the instantiation `C<A, int>', we can deduce that
24520 `T' is `A' but unify () does not check whether `typename T::X'
24521 is `int'. */
24532 /* We only need to check the innermost arguments; the other
24533 arguments will always agree. */
24538 /* Now that we have bindings for all of the template arguments,
24539 ensure that the arguments deduced for the template template
24540 parameters have compatible template parameter lists. See the use
24541 of template_template_parm_bindings_ok_p in fn_type_unification
24542 for more information. */
24547 }
24549 // Compare two function templates T1 and T2 by deducing bindings
24550 // from one against the other. If both deductions succeed, compare
24551 // constraints to see which is more constrained.
24552 static int
24554 {
24559 {
24562 }
24565 {
24568 }
24570 // If both deductions succeed, then one may be more constrained.
24575 }
24577 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
24578 Return the TREE_LIST node with the most specialized template, if
24579 any. If there is no most specialized template, the error_mark_node
24580 is returned.
24582 Note that this function does not look at, or modify, the
24583 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
24584 returned is one of the elements of INSTANTIATIONS, callers may
24585 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
24586 and retrieve it from the value returned. */
24588 tree
24590 {
24597 {
24603 {
24604 /* Equally specialized, move to next function. If there
24605 is no next function, nothing's most specialized. */
24610 }
24611 }
24614 /* Now verify that champ is better than everything earlier in the
24615 instantiation list. */
24618 {
24621 }
24622 }
24624 processing_template_decl--;
24630 }
24632 /* If DECL is a specialization of some template, return the most
24633 general such template. Otherwise, returns NULL_TREE.
24635 For example, given:
24637 template <class T> struct S { template <class U> void f(U); };
24639 if TMPL is `template <class U> void S<int>::f(U)' this will return
24640 the full template. This function will not trace past partial
24641 specializations, however. For example, given in addition:
24643 template <class T> struct S<T*> { template <class U> void f(U); };
24645 if TMPL is `template <class U> void S<int*>::f(U)' this will return
24646 `template <class T> template <class U> S<T*>::f(U)'. */
24648 tree
24650 {
24652 {
24655 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
24656 template friend, or a FIELD_DECL for a capture pack. */
24659 }
24661 /* Look for more and more general templates. */
24663 {
24664 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
24665 (See cp-tree.h for details.) */
24674 /* Stop if we run into an explicitly specialized class template. */
24681 }
24684 }
24686 /* Return the most specialized of the template partial specializations
24687 which can produce TARGET, a specialization of some class or variable
24688 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
24689 a TEMPLATE_DECL node corresponding to the partial specialization, while
24690 the TREE_PURPOSE is the set of template arguments that must be
24691 substituted into the template pattern in order to generate TARGET.
24693 If the choice of partial specialization is ambiguous, a diagnostic
24694 is issued, and the error_mark_node is returned. If there are no
24695 partial specializations matching TARGET, then NULL_TREE is
24696 returned, indicating that the primary template should be used. */
24698 tree
24700 {
24702 tree t;
24703 tree champ;
24710 {
24714 }
24716 {
24719 }
24721 {
24725 }
24726 else
24731 /* For determining which partial specialization to use, only the
24732 innermost args are interesting. */
24734 {
24737 }
24739 /* The caller hasn't called push_to_top_level yet, but we need
24740 get_partial_spec_bindings to be done in non-template context so that we'll
24741 fully resolve everything. */
24742 processing_template_decl_sentinel ptds;
24745 {
24748 tree spec_tmpl;
24750 {
24751 /* Substitute in the template args from the enclosing class. */
24757 }
24758 else
24763 {
24767 /* Keep the candidate only if the constraints are satisfied,
24768 or if we're not compiling with concepts. */
24771 {
24774 }
24775 }
24776 }
24786 {
24789 ;
24790 else
24791 {
24793 {
24796 {
24799 }
24800 }
24802 }
24803 }
24807 {
24810 {
24813 }
24814 }
24817 {
24824 else
24828 {
24833 }
24836 }
24839 }
24841 /* Explicitly instantiate DECL. */
24843 void
24845 {
24850 /* An error occurred, for which grokdeclarator has already issued
24851 an appropriate message. */
24854 {
24857 }
24859 {
24862 else
24865 }
24871 {
24872 /* There is an asymmetry here in the way VAR_DECLs and
24873 FUNCTION_DECLs are handled by grokdeclarator. In the case of
24874 the latter, the DECL we get back will be marked as a
24875 template instantiation, and the appropriate
24876 DECL_TEMPLATE_INFO will be set up. This does not happen for
24877 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
24878 should handle VAR_DECLs as it currently handles
24879 FUNCTION_DECLs. */
24881 {
24884 }
24887 {
24890 }
24892 {
24897 }
24898 }
24900 {
24903 }
24904 else
24907 /* Check for various error cases. Note that if the explicit
24908 instantiation is valid the RESULT will currently be marked as an
24909 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
24910 until we get here. */
24913 {
24914 /* DR 259 [temp.spec].
24916 Both an explicit instantiation and a declaration of an explicit
24917 specialization shall not appear in a program unless the explicit
24918 instantiation follows a declaration of the explicit specialization.
24920 For a given set of template parameters, if an explicit
24921 instantiation of a template appears after a declaration of an
24922 explicit specialization for that template, the explicit
24923 instantiation has no effect. */
24925 }
24927 {
24928 /* [temp.spec]
24930 No program shall explicitly instantiate any template more
24931 than once.
24933 We check DECL_NOT_REALLY_EXTERN so as not to complain when
24934 the first instantiation was `extern' and the second is not,
24935 and EXTERN_P for the opposite case. */
24938 /* If an "extern" explicit instantiation follows an ordinary
24939 explicit instantiation, the template is instantiated. */
24942 }
24944 {
24947 }
24949 {
24952 }
24955 ;
24957 {
24960 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
24963 }
24964 else
24972 }
24974 static void
24976 {
24982 {
24985 }
24986 }
24988 /* Perform an explicit instantiation of template class T. STORAGE, if
24989 non-null, is the RID for extern, inline or static. COMPLAIN is
24990 nonzero if this is called from the parser, zero if called recursively,
24991 since the standard is unclear (as detailed below). */
24993 void
24995 {
24997 {
25001 else
25004 }
25009 {
25012 t);
25014 }
25016 /* At most one of these will be true. */
25022 {
25024 {
25027 "ISO C++ 1998 forbids the use of %<extern%> on "
25029 }
25030 else
25032 "ISO C++ forbids the use of %qE"
25041 else
25043 storage);
25044 }
25047 /* DR 259 [temp.spec].
25049 Both an explicit instantiation and a declaration of an explicit
25050 specialization shall not appear in a program unless the
25051 explicit instantiation follows a declaration of the explicit
25052 specialization.
25054 For a given set of template parameters, if an explicit
25055 instantiation of a template appears after a declaration of an
25056 explicit specialization for that template, the explicit
25057 instantiation has no effect. */
25061 {
25062 /* We've already instantiated the template. */
25064 /* [temp.spec]
25066 No program shall explicitly instantiate any template more
25067 than once.
25069 If EXTERN_P then this is ok. */
25075 }
25083 /* In contrast to implicit instantiation, where only the
25084 declarations, and not the definitions, of members are
25085 instantiated, we have here:
25087 [temp.explicit]
25089 An explicit instantiation that names a class template
25090 specialization is also an explicit instantiation of the same
25091 kind (declaration or definition) of each of its members (not
25092 including members inherited from base classes and members
25093 that are templates) that has not been previously explicitly
25094 specialized in the translation unit containing the explicit
25095 instantiation, provided that the associated constraints, if
25096 any, of that member are satisfied by the template arguments
25097 of the explicit instantiation. */
25101 && !static_p
25105 {
25110 }
25112 {
25118 }
25119 }
25121 /* Given a function DECL, which is a specialization of TMPL, modify
25122 DECL to be a re-instantiation of TMPL with the same template
25123 arguments. TMPL should be the template into which tsubst'ing
25124 should occur for DECL, not the most general template.
25126 One reason for doing this is a scenario like this:
25128 template <class T>
25129 void f(const T&, int i);
25131 void g() { f(3, 7); }
25133 template <class T>
25134 void f(const T& t, const int i) { }
25136 Note that when the template is first instantiated, with
25137 instantiate_template, the resulting DECL will have no name for the
25138 first parameter, and the wrong type for the second. So, when we go
25139 to instantiate the DECL, we regenerate it. */
25141 static void
25143 {
25144 /* The arguments used to instantiate DECL, from the most general
25145 template. */
25146 tree code_pattern;
25150 /* Make sure that we can see identifiers, and compute access
25151 correctly. */
25155 {
25156 tree decl_parm;
25157 tree pattern_parm;
25158 tree specs;
25167 /* Instantiate a dynamic exception-specification. noexcept will be
25168 handled below. */
25171 {
25177 specs);
25178 }
25180 /* Merge parameter declarations. */
25183 pattern_parm
25187 {
25188 tree parm_type;
25189 tree attributes;
25194 NULL_TREE);
25200 {
25203 }
25206 }
25207 /* Merge any parameters that match with the function parameter
25208 pack. */
25210 {
25212 tree expanded_types;
25213 /* Expand the TYPE_PACK_EXPANSION that provides the types for
25214 the parameters in this function parameter pack. */
25219 {
25220 tree parm_type;
25221 tree attributes;
25224 /* Rename the parameter to include the index. */
25233 {
25236 }
25238 }
25239 }
25240 /* Merge additional specifiers from the CODE_PATTERN. */
25246 }
25248 {
25257 }
25258 else
25262 }
25264 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
25265 substituted to get DECL. */
25267 tree
25269 {
25272 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
25273 for the instantiation. This is not always the most general
25274 template. Consider, for example:
25276 template <class T>
25277 struct S { template <class U> void f();
25278 template <> void f<int>(); };
25280 and an instantiation of S<double>::f<int>. We want TD to be the
25281 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
25283 more general template. */
25285 /* We must also deal with friend templates. Given:
25287 template <class T> struct S {
25288 template <class U> friend void f() {};
25289 };
25291 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
25292 so far as the language is concerned, but that's still
25293 where we get the pattern for the instantiation from. On
25294 other hand, if the definition comes outside the class, say:
25296 template <class T> struct S {
25297 template <class U> friend void f();
25298 };
25299 template <class U> friend void f() {}
25301 we don't need to look any further. That's what the check for
25302 DECL_INITIAL is for. */
25306 {
25307 /* The present template, TD, should not be a definition. If it
25308 were a definition, we should be using it! Note that we
25309 cannot restructure the loop to just keep going until we find
25310 a template with a definition, since that might go too far if
25311 a specialization was declared, but not defined. */
25313 /* Fetch the more general template. */
25315 }
25318 }
25320 /* Returns true if we need to instantiate this template instance even if we
25321 know we aren't going to emit it. */
25323 bool
25325 {
25326 /* We always instantiate inline functions so that we can inline them. An
25327 explicit instantiation declaration prohibits implicit instantiation of
25328 non-inline functions. With high levels of optimization, we would
25329 normally inline non-inline functions -- but we're not allowed to do
25330 that for "extern template" functions. Therefore, we check
25331 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
25335 /* And we need to instantiate static data members so that
25336 their initializers are available in integral constant
25337 expressions. */
25340 }
25342 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
25343 instantiate it now, modifying TREE_TYPE (fn). Returns false on
25344 error, true otherwise. */
25346 bool
25348 {
25351 /* Don't instantiate a noexcept-specification from template context. */
25357 {
25359 /* We're in start_preparsed_function, keep going. */
25366 }
25380 /* For a member friend template we can get a TEMPLATE_DECL. Let's use
25381 its FUNCTION_DECL for the rest of this function -- push_access_scope
25382 doesn't accept TEMPLATE_DECLs. */
25384 {
25387 }
25390 {
25395 }
25397 {
25401 {
25404 /* This might have failed because of an unparsed DMI, so
25405 let's try again later. */
25407 }
25409 {
25410 /* If hash_set::add returns true, the element was already there. */
25415 fn);
25417 }
25419 {
25426 {
25427 /* If needed, set current_class_ptr for the benefit of
25428 tsubst_copy/PARM_DECL. The exception pattern will
25429 refer to the parm of the template, not the
25430 instantiation. */
25433 {
25438 }
25439 }
25441 /* If this function is represented by a TEMPLATE_DECL, then
25442 the deferred noexcept-specification might still contain
25443 dependent types, even after substitution. And we need the
25444 dependency check functions to work in build_noexcept_spec. */
25448 /* Do deferred instantiation of the noexcept-specifier. */
25455 /* Build up the noexcept-specification. */
25465 }
25466 else
25471 }
25474 {
25475 /* This failed with a hard error, so let's go with false. */
25478 }
25485 }
25487 /* We're starting to process the function INST, an instantiation of PATTERN;
25488 add their parameters to local_specializations. */
25490 static void
25492 {
25496 {
25500 }
25502 {
25505 {
25508 }
25509 else
25510 {
25511 /* Register the (value) argument pack as a specialization of
25512 TMPL_PARM, then move on. */
25515 }
25516 }
25518 }
25520 /* Instantiate the body of D using PATTERN with ARGS. We have
25521 already determined PATTERN is the correct template to use.
25522 NESTED_P is true if this is a nested function, in which case
25523 PATTERN will be a FUNCTION_DECL not a TEMPLATE_DECL. */
25525 static void
25527 {
25532 {
25535 }
25536 else
25537 /* Only OMP reductions are nested. */
25544 bool push_to_top
25545 = !(current_function_decl
25551 else
25552 {
25557 }
25560 {
25561 /* The variable might be a lambda's extra scope, and that
25562 lambda's visibility depends on D's. */
25565 }
25567 /* Mark D as instantiated so that recursive calls to
25568 instantiate_decl do not try to instantiate it again. */
25572 /* Regenerate the declaration in case the template has been modified
25573 by a subsequent redeclaration. */
25576 /* We already set the file and line above. Reset them now in case
25577 they changed as a result of calling regenerate_decl_from_template. */
25581 {
25582 /* Clear out DECL_RTL; whatever was there before may not be right
25583 since we've reset the type of the declaration. */
25587 /* The initializer is placed in DECL_INITIAL by
25588 regenerate_decl_from_template so we don't need to
25589 push/pop_access_scope again here. Pull it out so that
25590 cp_finish_decl can process it. */
25596 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
25597 initializer. That function will defer actual emission until
25598 we have a chance to determine linkage. */
25601 /* Enter the scope of D so that access-checking works correctly. */
25611 }
25615 {
25616 /* Set up the list of local specializations. */
25620 /* Set up context. */
25623 else
25624 {
25628 }
25630 /* Create substitution entries for the parameters. */
25633 /* Substitute into the body of the function. */
25637 else
25638 {
25643 /* Set the current input_location to the end of the function
25644 so that finish_function knows where we are. */
25645 input_location
25648 /* Remember if we saw an infinite loop in the template. */
25649 current_function_infinite_loop
25651 }
25653 /* Finish the function. */
25656 else
25657 {
25660 }
25664 }
25666 /* We're not deferring instantiation any more. */
25672 else
25677 }
25679 /* Produce the definition of D, a _DECL generated from a template. If
25680 DEFER_OK is true, then we don't have to actually do the
25681 instantiation now; we just have to do it sometime. Normally it is
25682 an error if this is an explicit instantiation but D is undefined.
25683 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
25684 instantiated class template. */
25686 tree
25688 {
25690 tree gen_args;
25691 tree args;
25692 tree td;
25693 tree code_pattern;
25694 tree spec;
25695 tree gen_tmpl;
25703 /* This function should only be used to instantiate templates for
25704 functions and static member variables. */
25707 /* A concept is never instantiated. */
25712 /* Variables are never deferred; if instantiation is required, they
25713 are instantiated right away. That allows for better code in the
25714 case that an expression refers to the value of the variable --
25715 if the variable has a constant value the referring expression can
25716 take advantage of that fact. */
25720 /* Don't instantiate cloned functions. Instead, instantiate the
25721 functions they cloned. */
25730 /* D has already been instantiated or explicitly specialized, so
25731 there's nothing for us to do here.
25733 It might seem reasonable to check whether or not D is an explicit
25734 instantiation, and, if so, stop here. But when an explicit
25735 instantiation is deferred until the end of the compilation,
25736 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
25737 the instantiation. */
25740 /* Check to see whether we know that this template will be
25741 instantiated in some other file, as with "extern template"
25742 extension. */
25745 /* In general, we do not instantiate such templates. */
25752 /* We should already have the extra args. */
25756 /* And what's in the hash table should match D. */
25758 == d
25761 /* This needs to happen before any tsubsting. */
25767 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
25768 for the instantiation. */
25773 {
25774 /* Look up an explicit specialization, if any. */
25778 {
25781 }
25782 }
25786 /* We should never be trying to instantiate a member of a class
25787 template or partial specialization. */
25792 /* In the case of a friend template whose definition is provided
25793 outside the class, we may have too many arguments. Drop the
25794 ones we don't need. The same is true for specializations. */
25795 args = get_innermost_template_args
25799 {
25805 }
25806 else
25807 {
25811 else
25813 }
25815 /* We may be in the middle of deferred access check. Disable it now. */
25818 /* Unless an explicit instantiation directive has already determined
25819 the linkage of D, remember that a definition is available for
25820 this entity. */
25830 /* If D is a member of an explicitly instantiated class template,
25831 and no definition is available, treat it like an implicit
25832 instantiation. */
25835 {
25836 /* Leave linkage flags alone on instantiations with anonymous
25837 visibility. */
25839 {
25842 }
25844 }
25846 /* Defer all other templates, unless we have been explicitly
25847 forbidden from doing so. */
25849 template. */
25850 ! pattern_defined
25851 /* If it's OK to postpone instantiation, do so. */
25852 || defer_ok
25853 /* If this is a static data member that will be defined
25854 elsewhere, we don't want to instantiate the entire data
25855 member, but we do want to instantiate the initializer so that
25856 we can substitute that elsewhere. */
25858 /* Handle here a deleted function too, avoid generating
25859 its body (c++/61080). */
25861 {
25862 /* The definition of the static data member is now required so
25863 we must substitute the initializer. */
25867 {
25868 tree ns;
25869 tree init;
25878 args,
25881 /* If instantiating the initializer involved instantiating this
25882 again, don't call cp_finish_decl twice. */
25884 {
25885 /* Make sure the initializer is still constant, in case of
25886 circular dependency (template/instantiate6.C). */
25887 const_init
25891 LOOKUP_ONLYCONVERTING);
25892 }
25896 }
25898 /* We restore the source position here because it's used by
25899 add_pending_template. */
25905 /* [temp.explicit]
25907 The definition of a non-exported function template, a
25908 non-exported member function template, or a non-exported
25909 member function or static data member of a class template
25910 shall be present in every translation unit in which it is
25911 explicitly instantiated. */
25915 /* If we're in unevaluated context, we just wanted to get the
25916 constant value; this isn't an odr use, so don't queue
25917 a full instantiation. */
25919 /* ??? Historically, we have instantiated inline functions, even
25920 when marked as "extern template". */
25923 }
25924 else
25925 {
25929 }
25939 }
25941 /* Run through the list of templates that we wish we could
25942 instantiate, and instantiate any we can. RETRIES is the
25943 number of times we retry pending template instantiation. */
25945 void
25947 {
25951 /* Instantiating templates may trigger vtable generation. This in turn
25952 may require further template instantiations. We place a limit here
25953 to avoid infinite loop. */
25955 {
25959 "template instantiation depth exceeds maximum of %d"
25960 " instantiating %q+D, possibly from virtual table generation"
25964 /* Pretend that we defined it. */
25967 }
25969 do
25970 {
25975 {
25980 {
25982 {
25997 }
26000 }
26001 else
26002 {
26005 {
26006 instantiation
26012 }
26016 }
26019 {
26020 /* If INSTANTIATION has been instantiated, then we don't
26021 need to consider it again in the future. */
26026 }
26027 else
26028 {
26031 }
26034 }
26036 }
26040 }
26042 /* Substitute ARGVEC into T, which is a list of initializers for
26043 either base class or a non-static data member. The TREE_PURPOSEs
26044 are DECLs, and the TREE_VALUEs are the initializer values. Used by
26045 instantiate_decl. */
26047 static tree
26049 {
26054 {
26055 tree decl;
26056 tree init;
26062 {
26063 tree expr;
26064 tree arg;
26066 /* Expand the base class expansion type into separate base
26067 classes. */
26069 tf_warning_or_error,
26070 NULL_TREE);
26074 /* We'll be building separate TREE_LISTs of arguments for
26075 each base. */
26081 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
26082 expand each argument in the TREE_VALUE of t. */
26089 /* VOID_TYPE_NODE is used to indicate
26090 value-initialization. */
26091 {
26094 }
26095 else
26096 {
26097 /* Substitute parameter packs into each argument in the
26098 TREE_LIST. */
26101 {
26102 tree expanded_exprs;
26104 /* Expand the argument. */
26106 expanded_exprs
26108 tf_warning_or_error,
26109 NULL_TREE);
26113 /* Prepend each of the expanded expressions to the
26114 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
26116 {
26121 }
26122 }
26125 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
26126 since we built them backwards. */
26128 {
26131 }
26132 }
26133 }
26136 {
26138 {
26142 }
26143 else
26144 {
26145 tree tmp;
26160 /* If we had an initializer but it instantiated to nothing,
26161 value-initialize the object. This will only occur when
26162 the initializer was a pack expansion where the parameter
26163 packs used in that expansion were of length zero. */
26166 }
26170 {
26172 decl);
26174 }
26175 /* Look for a target constructor. */
26179 {
26182 {
26186 }
26188 }
26191 {
26193 /* Carry over the dummy TREE_TYPE node containing the source
26194 location. */
26198 }
26199 }
26200 }
26202 }
26204 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
26206 static void
26208 {
26213 else
26215 }
26217 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
26218 is the instantiation (which should have been created with
26219 start_enum) and ARGS are the template arguments to use. */
26221 static void
26223 {
26224 tree e;
26230 {
26231 tree value;
26232 tree decl;
26235 /* Note that in a template enum, the TREE_VALUE is the
26236 CONST_DECL, not the corresponding INTEGER_CST. */
26241 /* Give this enumeration constant the correct access. */
26244 /* Actually build the enumerator itself. Here we're assuming that
26245 enumerators can't have dependent attributes. */
26248 }
26258 }
26260 /* DECL is a FUNCTION_DECL that is a template specialization. Return
26261 its type -- but without substituting the innermost set of template
26262 arguments. So, innermost set of template parameters will appear in
26263 the type. */
26265 tree
26267 {
26268 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
26270 }
26272 /* Return truthvalue if we're processing a template different from
26273 the last one involved in diagnostics. */
26274 bool
26276 {
26278 }
26280 /* Remember current template involved in diagnostics. */
26281 void
26283 {
26285 }
26289 {
26291 }
26293 /* Return TRUE if current_function_decl is being instantiated, false
26294 otherwise. */
26296 bool
26298 {
26302 }
26304 /* [temp.param] Check that template non-type parm TYPE is of an allowable
26305 type. Return false for ok, true for disallowed. Issue error and
26306 inform messages under control of COMPLAIN. */
26308 static bool
26310 {
26321 {
26323 {
26328 }
26330 }
26337 /* A bound template template parm could later be instantiated to have a valid
26338 nontype parm type via an alias template. */
26345 {
26353 {
26354 auto_diagnostic_group d;
26358 }
26360 }
26362 {
26367 }
26370 {
26373 else
26375 type);
26376 }
26378 }
26380 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
26381 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
26383 static bool
26385 {
26386 tree scope;
26388 /* [temp.dep.type]
26390 A type is dependent if it is:
26392 -- a template parameter. Template template parameters are types
26393 for us (since TYPE_P holds true for them) so we handle
26394 them here. */
26398 /* -- a qualified-id with a nested-name-specifier which contains a
26399 class-name that names a dependent type or whose unqualified-id
26400 names a dependent type. */
26404 /* An alias template specialization can be dependent even if the
26405 resulting type is not. */
26409 /* -- a cv-qualified type where the cv-unqualified type is
26410 dependent.
26411 No code is necessary for this bullet; the code below handles
26412 cv-qualified types, and we don't want to strip aliases with
26413 TYPE_MAIN_VARIANT because of DR 1558. */
26414 /* -- a compound type constructed from any dependent type. */
26422 {
26423 tree arg_type;
26428 arg_type;
26433 /* A value-dependent noexcept-specifier makes the type dependent. */
26436 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
26437 affect overload resolution and treating it as dependent breaks
26438 things. Same for an unparsed noexcept expression. */
26444 }
26445 /* -- an array type constructed from any dependent type or whose
26446 size is specified by a constant expression that is
26447 value-dependent.
26449 We checked for type- and value-dependence of the bounds in
26450 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
26452 {
26457 }
26459 /* -- a template-id in which either the template name is a template
26460 parameter ... */
26463 /* ... or any of the template arguments is a dependent type or
26464 an expression that is type-dependent or value-dependent. */
26466 && (any_dependent_template_arguments_p
26470 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
26471 dependent; if the argument of the `typeof' expression is not
26472 type-dependent, then it should already been have resolved. */
26478 /* A template argument pack is dependent if any of its packed
26479 arguments are. */
26481 {
26487 }
26489 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
26490 be template parameters. */
26497 /* The standard does not specifically mention types that are local
26498 to template functions or local classes, but they should be
26499 considered dependent too. For example:
26501 template <int I> void f() {
26502 enum E { a = I };
26503 S<sizeof (E)> s;
26504 }
26506 The size of `E' cannot be known until the value of `I' has been
26507 determined. Therefore, `E' must be considered dependent. */
26511 /* Don't use type_dependent_expression_p here, as it can lead
26512 to infinite recursion trying to determine whether a lambda
26513 nested in a lambda is dependent (c++/47687). */
26517 && (any_dependent_template_arguments_p
26521 /* Other types are non-dependent. */
26523 }
26525 /* Returns TRUE if TYPE is dependent, in the sense of
26526 [temp.dep.type]. Note that a NULL type is considered dependent. */
26528 bool
26530 {
26531 /* If there are no template parameters in scope, then there can't be
26532 any dependent types. */
26534 {
26535 /* If we are not processing a template, then nobody should be
26536 providing us with a dependent type. */
26540 }
26542 /* If the type is NULL, we have not computed a type for the entity
26543 in question; in that case, the type is dependent. */
26547 /* Erroneous types can be considered non-dependent. */
26551 /* Getting here with global_type_node means we improperly called this
26552 function on the TREE_TYPE of an IDENTIFIER_NODE. */
26555 /* If we have not already computed the appropriate value for TYPE,
26556 do so now. */
26558 {
26561 }
26564 }
26566 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
26567 lookup. In other words, a dependent type that is not the current
26568 instantiation. */
26570 bool
26572 {
26575 }
26577 /* T is a SCOPE_REF. Return whether it represents a non-static member of
26578 an unknown base of 'this' (and is therefore instantiation-dependent). */
26580 static bool
26582 {
26599 }
26601 /* T is a SCOPE_REF; return whether we need to consider it
26602 instantiation-dependent so that we can check access at instantiation
26603 time even though we know which member it resolves to. */
26605 static bool
26607 {
26614 else
26616 }
26618 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
26619 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
26620 expression. */
26622 /* Note that this predicate is not appropriate for general expressions;
26623 only constant expressions (that satisfy potential_constant_expression)
26624 can be tested for value dependence. */
26626 bool
26628 {
26632 /* A type-dependent expression is also value-dependent. */
26637 {
26639 /* A dependent member function of the current instantiation. */
26643 /* A dependent member function of the current instantiation. */
26650 /* A name that has not been looked up -- must be dependent. */
26654 /* A non-type template parm. */
26658 /* A non-type template parm. */
26664 /* A constant with literal type and is initialized
26665 with an expression that is value-dependent. */
26667 /* FIXME cp_finish_decl doesn't fold reference initializers. */
26671 {
26674 /* __PRETTY_FUNCTION__ inside a template function is dependent
26675 on the name of the function. */
26677 /* It might be used in a template, but not a template
26678 function, in which case its DECL_VALUE_EXPR will be
26679 "top level". */
26682 }
26691 /* These expressions are value-dependent if the type to which
26692 the cast occurs is dependent or the expression being casted
26693 is value-dependent. */
26694 {
26700 /* A functional cast has a list of operands. */
26703 {
26704 /* If there are no operands, it must be an expression such
26705 as "int()". This should not happen for aggregate types
26706 because it would form non-constant expressions. */
26711 }
26717 }
26722 /* FALLTHRU */
26725 /* A `sizeof' expression is value-dependent if the operand is
26726 type-dependent or is a pack expansion. */
26735 /* An 'encode' expression is value-dependent if the operand is
26736 type-dependent. */
26745 /* All instantiation-dependent expressions should also be considered
26746 value-dependent. */
26754 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
26755 is value-dependent. */
26756 {
26765 }
26768 {
26785 }
26796 {
26800 }
26803 /* Treat all requires-expressions as value-dependent so
26804 we don't try to fold them. */
26811 {
26818 {
26820 /* In a call to a constexpr member function, look through the
26821 implicit ADDR_EXPR on the object argument so that it doesn't
26822 cause the call to be considered value-dependent. We also
26823 look through it in potential_constant_expression. */
26830 }
26832 }
26838 {
26840 tree val;
26847 }
26850 /* Treat a GNU statement expression as dependent to avoid crashing
26851 under instantiate_non_dependent_expr; it can't be constant. */
26855 /* A constant expression is value-dependent if any subexpression is
26856 value-dependent. */
26858 {
26865 {
26869 {
26872 /* In some cases, some of the operands may be missing.
26873 (For example, in the case of PREDECREMENT_EXPR, the
26874 amount to increment by may be missing.) That doesn't
26875 make the expression dependent. */
26878 }
26879 }
26883 }
26885 }
26887 /* The expression is not value-dependent. */
26889 }
26891 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
26892 [temp.dep.expr]. Note that an expression with no type is
26893 considered dependent. Other parts of the compiler arrange for an
26894 expression with type-dependent subexpressions to have no type, so
26895 this function doesn't have to be fully recursive. */
26897 bool
26899 {
26908 /* An unresolved name is always dependent. */
26914 /* A lambda-expression in template context is dependent. dependent_type_p is
26915 true for a lambda in the scope of a class or function template, but that
26916 doesn't cover all template contexts, like a default template argument. */
26920 /* A fold expression is type-dependent. */
26927 /* Some expression forms are never type-dependent. */
26940 /* The types of these expressions depends only on the type to which
26941 the cast occurs. */
26950 /* The types of these expressions depends only on the type created
26951 by the expression. */
26954 {
26955 /* For NEW_EXPR tree nodes created inside a template, either
26956 the object type itself or a TREE_LIST may appear as the
26957 operand 1. */
26960 /* This is an array type. We need to check array dimensions
26961 as well. */
26963 || value_dependent_expression_p
26965 /* Array type whose dimension has to be deduced. */
26969 else
26971 }
26974 {
26978 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
26979 contains an identifier associated by name lookup with one or more
26980 declarations declared with a dependent type, or...a
26981 nested-name-specifier or qualified-id that names a member of an
26982 unknown specialization. */
26985 }
26995 {
26996 tree elt;
27000 {
27003 }
27005 }
27007 /* A static data member of the current instantiation with incomplete
27008 array type is type-dependent, as the definition and specializations
27009 can have different bounds. */
27016 /* An array of unknown bound depending on a variadic parameter, eg:
27018 template<typename... Args>
27019 void foo (Args... args)
27020 {
27021 int arr[] = { args... };
27022 }
27024 template<int... vals>
27025 void bar ()
27026 {
27027 int arr[] = { vals... };
27028 }
27030 If the array has no length and has an initializer, it must be that
27031 we couldn't determine its length in cp_complete_array_type because
27032 it is dependent. */
27040 /* A function or variable template-id is type-dependent if it has any
27041 dependent template arguments. */
27045 {
27046 /* Consider the innermost template arguments, since those are the ones
27047 that come from the template-id; the template arguments for the
27048 enclosing class do not make it type-dependent unless they are used in
27049 the type of the decl. */
27051 && (any_dependent_template_arguments_p
27054 }
27056 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
27057 type-dependent. Checking this is important for functions with auto return
27058 type, which looks like a dependent type. */
27067 {
27071 }
27073 /* Always dependent, on the number of arguments if nothing else. */
27078 {
27083 {
27089 }
27090 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
27094 /* CO_AWAIT/YIELD_EXPR with unknown type is always dependent. */
27100 {
27105 }
27108 {
27115 }
27124 }
27126 /* The type of a non-type template parm declared with a placeholder type
27127 depends on the corresponding template argument, even though
27128 placeholders are not normally considered dependent. */
27135 /* Dependent type attributes might not have made it from the decl to
27136 the type yet. */
27142 }
27144 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
27145 type-dependent if the expression refers to a member of the current
27146 instantiation and the type of the referenced member is dependent, or the
27147 class member access expression refers to a member of an unknown
27148 specialization.
27150 This function returns true if the OBJECT in such a class member access
27151 expression is of an unknown specialization. */
27153 bool
27155 {
27156 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
27157 dependent. */
27162 }
27164 /* walk_tree callback function for instantiation_dependent_expression_p,
27165 below. Returns non-zero if a dependent subexpression is found. */
27167 static tree
27170 {
27172 {
27173 /* We don't have to worry about decltype currently because decltype
27174 of an instantiation-dependent expr is a dependent type. This
27175 might change depending on the resolution of DR 1172. */
27178 }
27181 {
27182 /* Don't treat an argument list as dependent just because it has no
27183 TREE_TYPE. */
27194 /* We'll check value-dependence separately. */
27197 /* Handle expressions with type operands. */
27202 {
27207 {
27210 else
27211 {
27214 }
27215 }
27217 }
27221 /* In a template, finish_class_member_access_expr creates a
27222 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
27223 type-dependent, so that we can check access control at
27224 instantiation time (PR 42277). See also Core issue 1273. */
27231 else
27234 /* Treat statement-expressions as dependent. */
27238 /* Treat requires-expressions as dependent. */
27243 /* Treat concept checks as dependent. */
27249 /* Treat concept checks as dependent. */
27261 }
27265 else
27267 }
27269 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
27270 sense defined by the ABI:
27272 "An expression is instantiation-dependent if it is type-dependent
27273 or value-dependent, or it has a subexpression that is type-dependent
27274 or value-dependent."
27276 Except don't actually check value-dependence for unevaluated expressions,
27277 because in sizeof(i) we don't care about the value of i. Checking
27278 type-dependence will in turn check value-dependence of array bounds/template
27279 arguments as needed. */
27281 bool
27283 {
27284 tree result;
27295 }
27297 /* As above, but also check value-dependence of the expression as a whole. */
27299 bool
27301 {
27305 }
27307 /* Like type_dependent_expression_p, but it also works while not processing
27308 a template definition, i.e. during substitution or mangling. */
27310 bool
27312 {
27318 }
27320 /* Returns TRUE if ARGS contains a type-dependent expression. */
27322 bool
27324 {
27326 tree arg;
27329 {
27332 }
27334 }
27336 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
27337 expressions) contains any type-dependent expressions. */
27339 bool
27341 {
27347 }
27349 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
27350 expressions) contains any value-dependent expressions. */
27352 bool
27354 {
27360 }
27362 /* Returns TRUE if the ARG (a template argument) is dependent. */
27364 bool
27366 {
27370 /* Assume a template argument that was wrongly written by the user
27371 is dependent. This is consistent with what
27372 any_dependent_template_arguments_p [that calls this function]
27373 does. */
27383 {
27386 /* A member template of a dependent class is not necessarily
27387 type-dependent, but it is a dependent template argument because it
27388 will be a member of an unknown specialization to that template. */
27391 }
27393 {
27397 {
27400 }
27403 }
27406 else
27408 }
27410 /* Returns true if ARGS (a collection of template arguments) contains
27411 any types that require structural equality testing. */
27413 bool
27415 {
27425 {
27428 {
27434 {
27435 /* Look inside the argument pack. */
27438 }
27441 {
27454 }
27455 }
27456 }
27459 }
27461 /* Returns true if ARGS (a collection of template arguments) contains
27462 any dependent arguments. */
27464 bool
27466 {
27476 {
27481 }
27484 }
27486 /* Returns true if ARGS contains any errors. */
27488 bool
27490 {
27498 {
27501 else
27503 }
27509 {
27514 }
27517 }
27519 /* Returns TRUE if the template TMPL is type-dependent. */
27521 bool
27523 {
27525 {
27530 }
27532 /* Template template parameters are dependent. */
27536 /* So are names that have not been looked up. */
27540 }
27542 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
27544 bool
27546 {
27549 }
27551 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
27552 are dependent. */
27554 bool
27556 {
27563 {
27588 {
27592 }
27596 {
27600 {
27606 /* If this loop has a class iterator with != comparison
27607 with increment other than i++/++i/i--/--i, make sure the
27608 increment is constant. */
27611 {
27614 else
27618 }
27619 }
27620 }
27621 }
27624 }
27626 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
27627 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
27628 no such TYPE can be found. Note that this function peers inside
27629 uninstantiated templates and therefore should be used only in
27630 extremely limited situations. ONLY_CURRENT_P restricts this
27631 peering to the currently open classes hierarchy (which is required
27632 when comparing types). */
27634 tree
27636 {
27637 tree scope;
27638 tree name;
27639 tree decl;
27641 tree pushed_scope;
27642 tree result;
27647 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
27650 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
27651 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of a
27652 TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL
27653 representing the typedef. In that case TYPE_IDENTIFIER (type) is
27654 not the non-qualified identifier of the TYPENAME_TYPE anymore.
27655 So by getting the TYPE_IDENTIFIER of the _main declaration_ of
27656 the TYPENAME_TYPE instead, we avoid messing up with a possible
27657 typedef variant case. */
27660 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
27661 it first before we can figure out what NAME refers to. */
27663 {
27665 /* Given a class template A with a dependent base with nested type C,
27666 typedef typename A::C::C C will land us here, as trying to resolve
27667 the initial A::C leads to the local C typedef, which leads back to
27668 A::C::C. So we break the recursion now. */
27670 else
27672 }
27673 /* If we don't know what SCOPE refers to, then we cannot resolve the
27674 TYPENAME_TYPE. */
27677 /* If this is a typedef, we don't want to look inside (c++/11987). */
27680 /* If SCOPE isn't the template itself, it will not have a valid
27681 TYPE_FIELDS list. */
27683 /* scope is either the template itself or a compatible instantiation
27684 like X<T>, so look up the name in the original template. */
27686 /* If scope has no fields, it can't be a current instantiation. Check this
27687 before currently_open_class to avoid infinite recursion (71515). */
27690 /* If the SCOPE is not the current instantiation, there's no reason
27691 to look inside it. */
27694 /* Enter the SCOPE so that name lookup will be resolved as if we
27695 were in the class definition. In particular, SCOPE will no
27696 longer be considered a dependent type. */
27698 /* Look up the declaration. */
27700 tf_warning_or_error);
27704 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
27705 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
27711 {
27715 }
27718 {
27719 /* Obtain the template and the arguments. */
27722 {
27723 /* We get here with a plain identifier because a previous tentative
27724 parse of the nested-name-specifier as part of a ptr-operator saw
27725 ::template X<A>. The use of ::template is necessary in a
27726 ptr-operator, but wrong in a declarator-id.
27728 [temp.names]: In a qualified-id of a declarator-id, the keyword
27729 template shall not appear at the top level. */
27733 }
27735 /* Instantiate the template. */
27741 }
27743 /* Leave the SCOPE. */
27747 /* If we failed to resolve it, return the original typename. */
27751 /* If lookup found a typename type, resolve that too. */
27753 {
27754 /* Ill-formed programs can cause infinite recursion here, so we
27755 must catch that. */
27759 }
27761 /* Qualify the resulting type. */
27767 }
27769 /* EXPR is an expression which is not type-dependent. Return a proxy
27770 for EXPR that can be used to compute the types of larger
27771 expressions containing EXPR. */
27773 tree
27775 {
27777 tree inner_expr;
27779 /* When checking, try to get a constant value for all non-dependent
27780 expressions in order to expose bugs in *_dependent_expression_p
27781 and constexpr. This can affect code generation, see PR70704, so
27782 only do this for -fchecking=2. */
27785 /* Don't do this during nsdmi parsing as it can lead to
27786 unexpected recursive instantiations. */
27788 /* Don't do this during concept processing either and for
27789 the same reason. */
27795 /* Preserve OVERLOADs; the functions must be available to resolve
27796 types. */
27807 /* There is no need to return a proxy for a variable or enumerator. */
27810 /* Preserve string constants; conversions from string constants to
27811 "char *" are allowed, even though normally a "const char *"
27812 cannot be used to initialize a "char *". */
27815 /* Preserve void and arithmetic constants, as an optimization -- there is no
27816 reason to create a new node. */
27821 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
27822 There is at least one place where we want to know that a
27823 particular expression is a throw-expression: when checking a ?:
27824 expression, there are special rules if the second or third
27825 argument is a throw-expression. */
27829 /* Don't wrap an initializer list, we need to be able to look inside. */
27833 /* Don't wrap a dummy object, we need to be able to test for it. */
27852 /* If the type is unknown, it can't really be non-dependent */
27855 /* Otherwise, build a NON_DEPENDENT_EXPR. */
27858 }
27860 /* ARGS is a vector of expressions as arguments to a function call.
27861 Replace the arguments with equivalent non-dependent expressions.
27862 This modifies ARGS in place. */
27864 void
27866 {
27868 tree arg;
27871 {
27875 }
27876 }
27878 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
27879 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
27880 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
27882 static tree
27884 {
27899 }
27901 tree
27903 {
27905 }
27907 tree
27909 {
27911 }
27913 /* Return a C++17 deduction placeholder for class template TMPL. */
27915 tree
27917 {
27920 /* Our canonical type depends on the placeholder. */
27923 }
27925 /* True iff T is a C++17 class template deduction placeholder. */
27927 bool
27929 {
27931 }
27933 /* Make a "constrained auto" type-specifier. This is an auto or
27934 decltype(auto) type with constraints that must be associated after
27935 deduction. The constraint is formed from the given concept CON
27936 and its optional sequence of template arguments ARGS.
27938 TYPE must be the result of make_auto_type or make_decltype_auto_type. */
27940 static tree
27942 {
27943 /* Build the constraint. */
27954 /* Our canonical type depends on the constraint. */
27957 /* Attach the constraint to the type declaration. */
27959 }
27961 /* Make a "constrained auto" type-specifier. */
27963 tree
27965 {
27968 }
27970 /* Make a "constrained decltype(auto)" type-specifier. */
27972 tree
27974 {
27977 }
27979 /* Build and return a concept definition. Like other templates, the
27980 CONCEPT_DECL node is wrapped by a TEMPLATE_DECL. This returns the
27981 the TEMPLATE_DECL. */
27983 tree
27985 {
27991 /* A concept-definition shall not have associated constraints. */
27993 {
27996 }
27998 /* A concept-definition shall appear in namespace scope. Templates
27999 aren't allowed in block scope, so we only need to check for class
28000 scope. */
28002 {
28005 }
28007 /* Initially build the concept declaration; its type is bool. */
28012 /* Push the enclosing template. */
28014 }
28016 /* Given type ARG, return std::initializer_list<ARG>. */
28018 static tree
28020 {
28024 {
28028 "deducing from brace-enclosed initializer list"
28032 }
28038 }
28040 /* Replace auto in TYPE with std::initializer_list<auto>. */
28042 static tree
28044 {
28051 }
28053 /* Hash traits for hashing possibly constrained 'auto'
28054 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
28057 {
28060 };
28062 /* Hash the 'auto' T. */
28064 inline hashval_t
28066 {
28068 /* Matching constrained-type-specifiers denote the same template
28069 parameter, so hash the constraint. */
28071 else
28072 /* But unconstrained autos are all separate, so just hash the pointer. */
28074 }
28076 /* Compare two 'auto's. */
28080 {
28087 /* Two unconstrained autos are distinct. */
28092 }
28094 /* for_each_template_parm callback for extract_autos: if t is a (possibly
28095 constrained) auto, add it to the vector. */
28097 static int
28099 {
28102 {
28103 /* All the autos were built with index 0; fix that up now. */
28107 /* If this is a repeated constrained-type-specifier, use the index we
28108 chose before. */
28110 else
28111 {
28112 /* Otherwise this is new, so use the current count. */
28115 }
28117 }
28119 /* Always keep walking. */
28121 }
28123 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
28124 says they can appear anywhere in the type. */
28126 static tree
28128 {
28137 {
28142 }
28145 }
28147 /* The stem for deduction guide names. */
28150 /* Return the name for a deduction guide for class template TMPL. */
28152 tree
28154 {
28165 }
28167 /* True if NAME is the name of a deduction guide. */
28169 bool
28171 {
28176 }
28178 /* True if FN is a deduction guide. */
28180 bool
28182 {
28187 }
28189 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
28191 bool
28193 {
28200 }
28202 /* True if FN is a guide generated from a constructor template. */
28204 bool
28206 {
28214 }
28216 /* True if FN is an aggregate initialization guide or the copy deduction
28217 guide. */
28219 bool
28221 {
28225 /* Explicitly declared. */
28228 /* Derived from a constructor. */
28231 }
28233 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
28234 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
28235 template parameter types. Note that the handling of template template
28236 parameters relies on current_template_parms being set appropriately for the
28237 new template. */
28239 static tree
28242 {
28248 tree newtype;
28251 {
28258 }
28259 else
28260 {
28263 {
28264 // Substitute once to fix references to other template parameters.
28267 // Now substitute again to reduce the level of the auto.
28270 }
28271 else
28274 }
28276 tree newdecl
28281 tree newidx;
28284 {
28293 else
28297 {
28302 // First create a copy (ttargs) of tsubst_args with an
28303 // additional level for the template template parameter's own
28304 // template parameters (ttparms).
28305 tree ttparms = (INNERMOST_TEMPLATE_PARMS
28313 // Substitute ttargs into ttparms to fix references to
28314 // other template parameters.
28317 // Now substitute again with args based on tparms, to reduce
28318 // the level of the ttparms.
28321 complain);
28322 // Finally, tack the adjusted parms onto tparms.
28324 current_template_parms);
28326 }
28327 }
28328 else
28329 {
28331 tree newconst
28343 }
28346 }
28348 /* As rewrite_template_parm, but for the whole TREE_LIST representing a
28349 template parameter. */
28351 static tree
28354 {
28369 }
28371 /* Returns a C++17 class deduction guide template based on the constructor
28372 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
28373 guide, REFERENCE_TYPE for an implicit copy/move guide, or TREE_LIST for an
28374 aggregate initialization guide. */
28376 static tree
28378 {
28382 location_t loc;
28386 {
28390 }
28393 {
28395 {
28399 else
28401 }
28404 else
28414 }
28415 else
28416 {
28420 fn_tmpl
28428 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
28429 fully specialized args for the enclosing class. Strip those off, as
28430 the deduction guide won't have those template parameters. */
28433 /* Discard the 'this' parameter. */
28441 {
28444 /* For a member template constructor, we need to flatten the two
28445 template parameter lists into one, and then adjust the function
28446 signature accordingly. This gets...complicated. */
28449 /* For a member template we should have two levels of parms/args, one
28450 for the class and one for the constructor. We stripped
28451 specialized args for further enclosing classes above. */
28455 /* Template args for translating references to the two-level template
28456 parameters into references to the one-level template parameters we
28457 are creating. */
28462 /* Template parms for the constructor template. */
28465 /* Template parms for the class template. */
28469 /* Template parms for the deduction guide start as a copy of the
28470 template parms for the class. We set current_template_parms for
28471 lookup_template_class_1. */
28477 /* Now we need to rewrite the constructor parms to append them to the
28478 class parms. */
28480 {
28484 tree newelt
28490 }
28492 /* Now we have a final set of template parms to substitute into the
28493 function signature. */
28502 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped if
28503 cp_unevaluated_operand. */
28504 cp_evaluated ev;
28507 }
28508 else
28509 {
28510 /* Substitute in the same arguments to rewrite class members into
28511 references to members of an unknown specialization. */
28512 cp_evaluated ev;
28517 }
28522 }
28525 {
28526 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
28530 }
28534 FUNCTION_DECL,
28549 }
28551 /* Add to LIST the member types for the reshaped initializer CTOR. */
28553 static tree
28555 {
28559 {
28563 /* As in reshape_init_r, a non-aggregate or array-of-dependent-bound
28564 type gets a single initializer. */
28568 {
28574 }
28578 /* Give the trailing pack expansion parameter a default argument to
28579 match aggregate initialization behavior, even if we deduce the
28580 length of the pack separately to more than we have initializers. */
28582 /* if ei is of array type and xi is a braced-init-list or string literal,
28583 Ti is an rvalue reference to the declared type of ei */
28588 {
28590 ftype = cp_build_qualified_type
28592 ftype = (cp_build_reference_type
28594 }
28596 }
28599 }
28601 /* Return whether ETYPE is, or is derived from, a specialization of TMPL. */
28603 static bool
28605 {
28610 tree tparms = (INNERMOST_TEMPLATE_PARMS
28617 }
28619 /* Return a C++20 aggregate deduction candidate for TYPE initialized from
28620 INIT. */
28622 static tree
28624 {
28635 /* No aggregate candidate for copy-initialization. */
28637 {
28641 }
28643 /* If we encounter a problem, we just won't add the candidate. */
28648 {
28653 }
28655 {
28658 len;
28660 {
28666 }
28667 }
28668 else
28669 /* Aggregate initialization doesn't apply to an initializer expression. */
28673 {
28679 }
28682 }
28684 /* UGUIDES are the deduction guides for the underlying template of alias
28685 template TMPL; adjust them to be deduction guides for TMPL. */
28687 static tree
28689 {
28690 /* [over.match.class.deduct]: When resolving a placeholder for a deduced
28691 class type (9.2.8.2) where the template-name names an alias template A,
28692 the defining-type-id of A must be of the form
28694 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
28696 as specified in 9.2.8.2. The guides of A are the set of functions or
28697 function templates formed as follows. For each function or function
28698 template f in the guides of the template named by the simple-template-id
28699 of the defining-type-id, the template arguments of the return type of f
28700 are deduced from the defining-type-id of A according to the process in
28701 13.10.2.5 with the exception that deduction does not fail if not all
28702 template arguments are deduced. Let g denote the result of substituting
28703 these deductions into f. If substitution succeeds, form a function or
28704 function template f' with the following properties and add it to the set
28705 of guides of A:
28707 * The function type of f' is the function type of g.
28709 * If f is a function template, f' is a function template whose template
28710 parameter list consists of all the template parameters of A (including
28711 their default template arguments) that appear in the above deductions or
28712 (recursively) in their default template arguments, followed by the
28713 template parameters of f that were not deduced (including their default
28714 template arguments), otherwise f' is not a function template.
28716 * The associated constraints (13.5.2) are the conjunction of the
28717 associated constraints of g and a constraint that is satisfied if and only
28718 if the arguments of A are deducible (see below) from the return type.
28720 * If f is a copy deduction candidate (12.4.1.8), then f' is considered to
28721 be so as well.
28723 * If f was generated from a deduction-guide (12.4.1.8), then f' is
28724 considered to be so as well.
28726 * The explicit-specifier of f' is the explicit-specifier of g (if
28727 any). */
28729 /* This implementation differs from the above in two significant ways:
28731 1) We include all template parameters of A, not just some.
28732 2) The added constraint is same_type instead of deducible.
28734 I believe that while it's probably possible to construct a testcase that
28735 behaves differently with this simplification, it should have the same
28736 effect for real uses. Including all template parameters means that we
28737 deduce all parameters of A when resolving the call, so when we're in the
28738 constraint we don't need to deduce them again, we can just check whether
28739 the deduction produced the desired result. */
28748 {
28755 {
28759 /* Deduce template arguments for f from the type-id of A. */
28766 /* The number of parms for f' is the number of parms for A plus
28767 non-deduced parms of f. */
28775 /* First copy over the parms of A. */
28778 /* Now rewrite the non-deduced parms of f. */
28781 {
28789 }
28792 /* Substitute the deduced arguments plus the rewritten template
28793 parameters into f to get g. This covers the type, copyness,
28794 guideness, and explicit-specifier. */
28806 /* Substitute the associated constraints. */
28813 /* Add a constraint that the return type matches the instantiation of
28814 A with the same template arguments. */
28817 /* FIXME this should mean they don't compare as equivalent. */
28819 {
28822 }
28825 {
28828 }
28829 }
28830 else
28831 {
28832 /* For a non-template deduction guide, if the arguments of A aren't
28833 deducible from the return type, don't add the candidate. */
28841 }
28844 }
28847 }
28849 /* Return artificial deduction guides built from the constructors of class
28850 template TMPL. */
28852 static tree
28854 {
28859 {
28862 }
28867 {
28868 /* Skip inherited constructors. */
28874 }
28876 /* Add implicit default constructor deduction guide. */
28878 {
28880 complain);
28882 }
28884 /* Add copy guide. */
28885 {
28888 complain);
28890 }
28893 }
28897 /* Return the non-aggregate deduction guides for deducible template TMPL. The
28898 aggregate candidate is added separately because it depends on the
28899 initializer. Set ANY_DGUIDES_P if we find a non-implicit deduction
28900 guide. */
28902 static tree
28904 {
28907 {
28911 complain);
28912 }
28913 else
28914 {
28920 else
28922 }
28924 /* Cache the deduction guides for a template. We also remember the result of
28925 lookup, and rebuild everything if it changes; should be very rare. */
28929 {
28933 }
28934 else
28935 {
28938 }
28943 else
28944 {
28948 }
28952 }
28954 /* Return whether TMPL is a (class template argument-) deducible template. */
28956 bool
28958 {
28959 /* A deducible template is either a class template or is an alias template
28960 whose defining-type-id is of the form
28962 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
28964 where the nested-name-specifier (if any) is non-dependent and the
28965 template-name of the simple-template-id names a deducible template. */
28976 }
28978 /* Deduce template arguments for the class template placeholder PTYPE for
28979 template TMPL based on the initializer INIT, and return the resulting
28980 type. */
28982 static tree
28985 {
28986 /* We should have handled this in the caller. */
28990 /* Look through alias templates that just rename another template. */
28993 {
28997 }
28999 {
29000 /* This doesn't affect conforming C++17 code, so just pedwarn. */
29004 }
29007 /* Using the template parm as its own argument. */
29020 {
29024 {
29025 /* As an exception, the first phase in 16.3.1.7 (considering the
29026 initializer list as a single argument) is omitted if the
29027 initializer list consists of a single expression of type cv U,
29028 where U is a specialization of C or a class derived from a
29029 specialization of C. */
29033 }
29036 else
29038 }
29041 else
29044 /* Do this now to avoid problems with erroneous args later on. */
29054 /* Prune explicit deduction guides in copy-initialization context (but
29055 not copy-list-initialization). */
29058 {
29064 {
29065 /* Found a nonconverting guide, prune the candidates. */
29072 }
29073 }
29080 /* If this is list-initialization and the class has a list constructor, first
29081 try deducing from the list as a single argument, as [over.match.list]. */
29085 {
29089 }
29091 {
29097 {
29098 /* That didn't work, now try treating the list as a sequence of
29099 arguments. */
29102 }
29103 }
29106 {
29108 " of %qT, as it has no non-explicit deduction guides or "
29111 }
29113 {
29117 }
29120 {
29124 }
29127 {
29129 {
29140 }
29142 }
29143 /* [over.match.list]/1: In copy-list-initialization, if an explicit
29144 constructor is chosen, the initialization is ill-formed. */
29146 {
29149 {
29151 {
29152 // TODO: Pass down location from cp_finish_decl.
29154 "explicit deduction guide selected in "
29159 }
29161 }
29162 }
29164 /* If CTAD succeeded but the type doesn't have any explicit deduction
29165 guides, this deduction might not be what the user intended. */
29167 {
29173 "%qT may not intend to support class template argument "
29177 }
29180 }
29182 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
29183 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
29184 The CONTEXT determines the context in which auto deduction is performed
29185 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
29186 OUTER_TARGS are used during template argument deduction
29187 (context == adc_unify) to properly substitute the result, and is ignored
29188 in other contexts.
29190 For partial-concept-ids, extra args may be appended to the list of deduced
29191 template arguments prior to determining constraint satisfaction. */
29193 tree
29197 {
29198 tree targs;
29205 /* Defining a subset of type-dependent expressions that we can deduce
29206 from ahead of time isn't worth the trouble. */
29209 /* Similarly, we can't deduce from another undeduced decl. */
29213 /* We may be doing a partial substitution, but we still want to replace
29214 auto_node. */
29218 /* C++17 class template argument deduction. */
29222 /* Nothing we can do with this, even in deduction context. */
29225 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
29226 with either a new invented type template parameter U or, if the
29227 initializer is a braced-init-list (8.5.4), with
29228 std::initializer_list<U>. */
29230 {
29235 else
29236 {
29238 {
29242 "for deduction to %<std::initializer_list%>, use copy-"
29244 }
29246 }
29247 }
29253 {
29254 /* We don't recurse here because we can't deduce from a nested
29255 initializer_list. */
29259 }
29260 else
29267 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
29268 and initializer has array type, deduce cv-qualified array type. */
29270 complain);
29272 {
29284 {
29288 }
29290 {
29294 }
29295 }
29296 else
29297 {
29302 tree tparms;
29306 else
29307 {
29311 }
29315 DEDUCE_CALL,
29318 {
29320 /* Try again at instantiation time. */
29324 /* If type is error_mark_node a diagnostic must have been
29325 emitted by now. Also, having a mention to '<type error>'
29326 in the diagnostic is not really useful to the user. */
29327 {
29330 && (auto_node
29334 else
29337 DEDUCE_CALL,
29339 }
29341 }
29342 }
29344 /* Check any placeholder constraints against the deduced type. */
29347 {
29348 /* Use the deduced type to check the associated constraints. If we
29349 have a partial-concept-id, rebuild the argument list so that
29350 we check using the extra arguments. */
29358 {
29361 }
29362 else
29365 /* Rebuild the check using the deduced arguments. */
29369 {
29371 {
29372 auto_diagnostic_group d;
29374 {
29392 }
29394 }
29396 }
29397 }
29403 }
29405 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
29406 result. */
29408 tree
29410 {
29412 {
29415 }
29418 {
29421 {
29422 /* In an abbreviated function template we didn't know we were dealing
29423 with a function template when we saw the auto return type, so update
29424 it to have the correct level. */
29431 }
29432 }
29434 }
29436 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
29437 'decltype(auto)' or a deduced class template. */
29439 bool
29441 {
29446 else
29448 }
29450 /* for_each_template_parm callback for type_uses_auto. */
29452 int
29454 {
29456 }
29458 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
29459 a use of `auto'. Returns NULL_TREE otherwise. */
29461 tree
29463 {
29467 {
29468 /* The Concepts TS allows multiple autos in one type-specifier; just
29469 return the first one we find, do_auto_deduction will collect all of
29470 them. */
29474 else
29476 }
29479 else
29481 }
29483 /* Report ill-formed occurrences of auto types in ARGUMENTS. If
29484 concepts are enabled, auto is acceptable in template arguments, but
29485 only when TEMPL identifies a template class. Return TRUE if any
29486 such errors were reported. */
29488 bool
29490 {
29491 /* If there were previous errors, nevermind. */
29495 /* If TMPL is an identifier, we're parsing and we can't tell yet
29496 whether TMPL is supposed to be a type, a function or a variable.
29497 We'll only be able to tell during template substitution, so we
29498 expect to be called again then. If concepts are enabled and we
29499 know we have a type, we're ok. */
29507 /* Quickly search for any occurrences of auto; usually there won't
29508 be any, and then we'll avoid allocating the vector. */
29516 {
29521 }
29524 }
29526 /* Recursively walk over && expressions searching for EXPR. Return a reference
29527 to that expression. */
29530 {
29534 {
29539 }
29541 }
29543 /* Convert the generic type parameters in PARM that match the types given in the
29544 range [START_IDX, END_IDX) from the current_template_parms into generic type
29545 packs. */
29547 tree
29549 {
29560 {
29561 /* Create a distinct parameter pack type from the current parm and add it
29562 to the replacement args to tsubst below into the generic function
29563 parameter. */
29577 /* Replace the current template parameter with new pack. */
29580 /* Surgically adjust the associated constraint of adjusted parameter
29581 and it's corresponding contribution to the current template
29582 requirements. */
29584 {
29590 /* If there was a constraint, we also need to replace that in
29591 the template requirements, which we've already built. */
29595 }
29596 }
29602 /* If there are more levels then build up the replacement with the outer
29603 template parms. */
29607 replacement);
29610 }
29612 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
29613 0..N-1. */
29615 void
29617 {
29620 integer_type_node,
29621 NULL_TREE),
29625 CP_BUILT_IN_INTEGER_PACK);
29626 }
29628 /* Set up the hash tables for template instantiations. */
29630 void
29632 {
29638 }
29640 /* Print stats about the template hash tables for -fstats. */
29642 void
29644 {
29653 }
29655 #if CHECKING_P
29659 /* Verify that build_non_dependent_expr () works, for various expressions,
29660 and that location wrappers don't affect the results. */
29662 static void
29664 {
29667 /* Verify constants, without and with location wrappers. */
29684 }
29686 /* Verify that type_dependent_expression_p () works correctly, even
29687 in the presence of location wrapper nodes. */
29689 static void
29691 {
29696 /* If no templates are involved, nothing is type-dependent. */
29702 /* Within a template, an unresolved name is always type-dependent. */
29705 /* Ensure it copes with NULL_TREE and errors. */
29709 /* A USING_DECL in a template should be type-dependent, even if wrapped
29710 with a location wrapper (PR c++/83799). */
29719 }
29721 /* Run all of the selftests within this file. */
29723 void
29725 {
29728 }