| blob | 076f788281efaa70e506967eef21e15dbd762185 |
1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2023 Free Software Foundation, Inc.
3 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
4 Rewritten by Jason Merrill (jason@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Known bugs or deficiencies include:
24 all methods must be provided in header files; can't use a source
25 file that contains only the method templates and "just win".
27 Fixed by: C++20 modules. */
50 /* The type of functions taking a tree, and some additional data, and
51 returning an int. */
54 /* The PENDING_TEMPLATES is a list of templates whose instantiations
55 have been deferred, either because their definitions were not yet
56 available, or because we were putting off doing the work. */
58 {
61 };
75 /* Live only within one (recursive) call to tsubst_expr. We use
76 this to pass the statement expression node from the STMT_EXPR
77 to the EXPR_STMT that is its result. */
80 // -------------------------------------------------------------------------- //
81 // Local Specialization Stack
82 //
83 // Implementation of the RAII helper for creating new local
84 // specializations.
87 {
89 ;
92 else
94 }
97 {
99 {
102 }
103 }
105 /* True if we've recursed into fn_type_unification too many times. */
109 {
113 };
115 /* The general template is not in these tables. */
120 /* Contains canonical template parameter types. The vector is indexed by
121 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
122 TREE_LIST, whose TREE_VALUEs contain the canonical template
123 parameters of various types and levels. */
126 #define UNIFY_ALLOW_NONE 0
127 #define UNIFY_ALLOW_MORE_CV_QUAL 1
128 #define UNIFY_ALLOW_LESS_CV_QUAL 2
129 #define UNIFY_ALLOW_DERIVED 4
130 #define UNIFY_ALLOW_INTEGER 8
131 #define UNIFY_ALLOW_OUTER_LEVEL 16
132 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
133 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
136 tbr_incomplete_type,
137 tbr_ambiguous_baseclass,
138 tbr_success
139 };
225 /* Make the current scope suitable for access checking when we are
226 processing T. T can be FUNCTION_DECL for instantiated function
227 template, VAR_DECL for static member variable, or TYPE_DECL for
228 for a class or alias template (needed by instantiate_decl). */
230 void
232 {
244 /* An artificial deduction guide should have the same access as
245 the constructor. */
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 {
272 else
274 }
276 /* Do any processing required when DECL (a member template
277 declaration) is finished. Returns the TEMPLATE_DECL corresponding
278 to DECL, unless it is a specialization, in which case the DECL
279 itself is returned. */
281 tree
283 {
290 {
291 tree type;
299 {
303 }
305 }
310 {
312 {
315 }
316 else
318 }
319 else
324 }
326 /* Create a template info node. */
328 tree
330 {
335 }
337 /* Return the template info node corresponding to T, whatever T is. */
339 tree
341 {
363 }
365 /* Returns the template nesting level of the indicated class TYPE.
367 For example, in:
368 template <class T>
369 struct A
370 {
371 template <class U>
372 struct B {};
373 };
375 A<T>::B<U> has depth two, while A<T> has depth one.
376 Both A<T>::B<int> and A<int>::B<U> have depth one, if
377 they are instantiations, not specializations.
379 This function is guaranteed to return 0 if passed NULL_TREE so
380 that, for example, `template_class_depth (current_class_type)' is
381 always safe. */
383 int
385 {
389 {
399 {
402 else
404 }
407 else
409 }
412 }
414 /* Return TRUE if NODE instantiates a template that has arguments of
415 its own, be it directly a primary template or indirectly through a
416 partial specializations. */
417 static bool
419 {
431 /* So now we know we have a specialization, but it could be a full
432 or a partial specialization. To tell which, compare the depth of
433 its template arguments with those of its context. */
442 }
444 /* Subroutine of maybe_begin_member_template_processing.
445 Returns true if processing DECL needs us to push template parms. */
447 static bool
449 {
455 }
457 /* Subroutine of maybe_begin_member_template_processing.
458 Push the template parms in PARMS, starting from LEVELS steps into the
459 chain, and ending at the beginning, since template parms are listed
460 innermost first. */
462 static void
464 {
472 current_template_parms
480 NULL);
482 {
491 {
498 /* Push the CONST_DECL. */
504 }
505 }
506 }
508 /* Restore the template parameter context for a member template, a
509 friend template defined in a class definition, or a non-template
510 member of template class. */
512 void
514 {
515 tree parms;
520 {
523 /* Disregard full specializations (c++/60999). */
526 }
529 {
534 {
537 }
540 }
542 /* Remember how many levels of template parameters we pushed so that
543 we can pop them later. */
545 }
547 /* Undo the effects of maybe_begin_member_template_processing. */
549 void
551 {
560 {
564 }
565 }
567 /* Return a new template argument vector which contains all of ARGS,
568 but has as its innermost set of arguments the EXTRA_ARGS. */
570 tree
572 {
573 tree new_args;
591 }
593 /* Like add_to_template_args, but only the outermost ARGS are added to
594 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
595 (EXTRA_ARGS) levels are added. This function is used to combine
596 the template arguments from a partial instantiation with the
597 template arguments used to attain the full instantiation from the
598 partial instantiation.
600 If ARGS is a TEMPLATE_DECL, use its parameters as args. */
602 tree
604 {
605 tree new_args;
610 {
613 }
615 /* If there are more levels of EXTRA_ARGS than there are ARGS,
616 something very fishy is going on. */
619 /* If *all* the new arguments will be the EXTRA_ARGS, just return
620 them. */
624 /* For the moment, we make ARGS look like it contains fewer levels. */
629 /* Now, we restore ARGS to its full dimensions. */
633 }
635 /* Return the N levels of innermost template arguments from the ARGS. */
637 tree
639 {
640 tree new_args;
646 /* If N is 1, just return the innermost set of template arguments. */
650 /* If we're not removing anything, just return the arguments we were
651 given. */
657 /* Make a new set of arguments, not containing the outer arguments. */
664 }
666 /* The inverse of get_innermost_template_args: Return all but the innermost
667 EXTRA_LEVELS levels of template arguments from the ARGS. */
669 static tree
671 {
672 tree new_args;
678 /* If N is 1, just return the outermost set of template arguments. */
682 /* If we're not removing anything, just return the arguments we were
683 given. */
688 /* Make a new set of arguments, not containing the inner arguments. */
695 }
697 /* We've got a template header coming up; push to a new level for storing
698 the parms. */
700 void
702 {
703 /* We use a non-tag-transparent scope here, which causes pushtag to
704 put tags in this scope, rather than in the enclosing class or
705 namespace scope. This is the right thing, since we want
706 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
707 global template class, push_template_decl handles putting the
708 TEMPLATE_DECL into top-level scope. For a nested template class,
709 e.g.:
711 template <class T> struct S1 {
712 template <class T> struct S2 {};
713 };
715 pushtag contains special code to insert the TEMPLATE_DECL for S2
716 at the right scope. */
722 /* Add a dummy parameter level while we process the parameter list. */
723 current_template_parms
726 current_template_parms);
727 }
729 /* This routine is called when a specialization is declared. If it is
730 invalid to declare a specialization here, an error is reported and
731 false is returned, otherwise this routine will return true. */
733 static bool
735 {
738 /* [temp.expl.spec]
740 An explicit specialization shall be declared in the namespace of
741 which the template is a member, or, for member templates, in the
742 namespace of which the enclosing class or enclosing class
743 template is a member. An explicit specialization of a member
744 function, member class or static data member of a class template
745 shall be declared in the namespace of which the class template
746 is a member. */
748 {
751 }
753 /* [temp.expl.spec]
755 In an explicit specialization declaration for a member of a class
756 template or a member template that appears in namespace scope,
757 the member template and some of its enclosing class templates may
758 remain unspecialized, except that the declaration shall not
759 explicitly specialize a class member template if its enclosing
760 class templates are not explicitly specialized as well. */
762 {
765 }
768 }
770 /* We've just seen template <>. */
772 bool
774 {
778 }
780 /* Called at then end of processing a declaration preceded by
781 template<>. */
783 void
785 {
788 }
790 /* Any template <>'s that we have seen thus far are not referring to a
791 function specialization. */
793 void
795 {
798 }
800 /* We've just seen a template header. If SPECIALIZATION is nonzero,
801 it was of the form template <>. */
803 static void
805 {
807 template_header_count++;
808 }
810 /* We're beginning an explicit instantiation. */
812 void
814 {
817 }
820 void
822 {
825 }
827 /* An explicit specialization or partial specialization of TMPL is being
828 declared. Check that the namespace in which the specialization is
829 occurring is permissible. Returns false iff it is invalid to
830 specialize TMPL in the current namespace. */
832 static bool
834 {
837 /* [tmpl.expl.spec]
839 An explicit specialization shall be declared in a namespace enclosing the
840 specialized template. An explicit specialization whose declarator-id is
841 not qualified shall be declared in the nearest enclosing namespace of the
842 template, or, if the namespace is inline (7.3.1), any namespace from its
843 enclosing namespace set. */
846 {
849 }
852 /* Same or enclosing namespace. */
854 else
855 {
856 auto_diagnostic_group d;
862 }
863 }
865 /* SPEC is an explicit instantiation. Check that it is valid to
866 perform this explicit instantiation in the current namespace. */
868 static void
870 {
871 tree ns;
873 /* DR 275: An explicit instantiation shall appear in an enclosing
874 namespace of its template. */
880 }
882 /* Returns true if TYPE is a new partial specialization that needs to be
883 set up. This may also modify TYPE to point to the correct (new or
884 existing) constrained partial specialization. */
886 static bool
888 {
889 /* An implicit instantiation of an incomplete type implies
890 the definition of a new class template.
892 template<typename T>
893 struct S;
895 template<typename T>
896 struct S<T*>;
898 Here, S<T*> is an implicit instantiation of S whose type
899 is incomplete. */
903 /* It can also be the case that TYPE is a completed specialization.
904 Continuing the previous example, suppose we also declare:
906 template<typename T>
907 requires Integral<T>
908 struct S<T*>;
910 Here, S<T*> refers to the specialization S<T*> defined
911 above. However, we need to differentiate definitions because
912 we intend to define a new partial specialization. In this case,
913 we rely on the fact that the constraints are different for
914 this declaration than that above.
916 Note that we also get here for injected class names and
917 late-parsed template definitions. We must ensure that we
918 do not create new type declarations for those cases. */
920 {
924 /* If there are no template parameters, this cannot be a new
925 partial template specialization? */
929 /* The injected-class-name is not a new partial specialization. */
933 /* If the constraints are not the same as those of the primary
934 then, we can probably create a new specialization. */
938 {
942 }
944 /* Also, if there's a pre-existing specialization with matching
945 constraints, then this also isn't new. */
948 {
954 {
957 }
959 }
961 /* Create a new type node (and corresponding type decl)
962 for the newly declared specialization. */
967 /* We only need a separate type node for storing the definition of this
968 partial specialization; uses of S<T*> are unconstrained, so all are
969 equivalent. So keep TYPE_CANONICAL the same. */
972 /* Build the corresponding type decl. */
984 }
987 }
989 /* The TYPE is being declared. If it is a template type, that means it
990 is a partial specialization. Do appropriate error-checking. */
992 tree
994 {
995 tree context;
1000 /* A lambda that appears in specialization context is not itself a
1001 specialization. */
1005 /* An injected-class-name is not a specialization. */
1010 {
1014 }
1019 {
1025 else
1028 }
1030 {
1031 /* This is for ordinary explicit specialization and partial
1032 specialization of a template class such as:
1034 template <> class C<int>;
1036 or:
1038 template <class T> class C<T*>;
1040 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
1043 {
1050 {
1055 }
1056 }
1062 /* Trying to define a specialization either without a template<> header
1063 or in an inappropriate place. We've already given an error, so just
1064 bail now so we don't actually define the specialization. */
1066 }
1072 {
1073 /* This is for an explicit specialization of member class
1074 template according to [temp.expl.spec/18]:
1076 template <> template <class U> class C<int>::D;
1078 The context `C<int>' must be an implicit instantiation.
1079 Otherwise this is just a member class template declared
1080 earlier like:
1082 template <> class C<int> { template <class U> class D; };
1083 template <> template <class U> class C<int>::D;
1085 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1086 while in the second case, `C<int>::D' is a primary template
1087 and `C<T>::D' may not exist. */
1091 {
1092 tree t;
1097 {
1100 type))
1103 }
1105 /* Check for invalid specialization after instantiation:
1107 template <> template <> class C<int>::D<int>;
1108 template <> template <class U> class C<int>::D; */
1112 {
1116 {
1117 /* We already have a full specialization of this partial
1118 instantiation, or a full specialization has been
1119 looked up but not instantiated. Reassign it to the
1120 new member specialization template. */
1121 spec_entry elt;
1134 spec_entry **slot
1139 }
1140 else
1141 /* But if we've had an implicit instantiation, that's a
1142 problem ([temp.expl.spec]/6). */
1145 }
1147 /* Mark TYPE as a specialization. And as a result, we only
1148 have one level of template argument for the innermost
1149 class template. */
1154 }
1155 }
1157 {
1158 /* Someday C++0x may allow for enum template specialization. */
1163 else
1164 {
1167 }
1168 }
1171 }
1173 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1174 gone through coerce_template_parms by now. */
1176 static void
1178 {
1180 {
1189 /* Allow typedefs on the type of a non-type argument, since a
1191 else
1193 }
1194 }
1196 static void
1198 {
1203 }
1205 /* Retrieve the specialization (in the sense of [temp.spec] - a
1206 specialization is either an instantiation or an explicit
1207 specialization) of TMPL for the given template ARGS. If there is
1208 no such specialization, return NULL_TREE. The ARGS are a vector of
1209 arguments, or a vector of vectors of arguments, in the case of
1210 templates with more than one level of parameters.
1212 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1213 then we search for a partial specialization matching ARGS. This
1214 parameter is ignored if TMPL is not a class template.
1216 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1217 result is a NONTYPE_ARGUMENT_PACK. */
1219 static tree
1221 {
1231 /* There should be as many levels of arguments as there are
1232 levels of parameters. */
1241 /* Lambda functions in templates aren't instantiated normally, but through
1242 tsubst_lambda_expr. */
1246 spec_entry elt;
1254 else
1263 }
1265 /* Like retrieve_specialization, but for local declarations. */
1267 tree
1269 {
1275 }
1277 /* Returns nonzero iff DECL is a specialization of TMPL. */
1279 int
1281 {
1282 tree t;
1285 {
1291 }
1292 else
1293 {
1302 }
1305 }
1307 /* Returns nonzero iff DECL is a specialization of friend declaration
1308 FRIEND_DECL according to [temp.friend]. */
1310 bool
1312 {
1319 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1320 of a template class, we want to check if DECL is a specialization
1321 if this. */
1326 {
1327 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1330 }
1335 /* There is nothing to do if this is not a template friend. */
1342 /* [temp.friend/6]
1343 A member of a class template may be declared to be a friend of a
1344 non-template class. In this case, the corresponding member of
1345 every specialization of the class template is a friend of the
1346 class granting friendship.
1348 For example, given a template friend declaration
1350 template <class T> friend void A<T>::f();
1352 the member function below is considered a friend
1354 template <> struct A<int> {
1355 void f();
1356 };
1358 For this type of template friend, TEMPLATE_DEPTH below will be
1359 nonzero. To determine if DECL is a friend of FRIEND, we first
1360 check if the enclosing class is a specialization of another. */
1367 {
1368 /* Next, we check the members themselves. In order to handle
1369 a few tricky cases, such as when FRIEND_DECL's are
1371 template <class T> friend void A<T>::g(T t);
1372 template <class T> template <T t> friend void A<T>::h();
1374 and DECL's are
1376 void A<int>::g(int);
1377 template <int> void A<int>::h();
1379 we need to figure out ARGS, the template arguments from
1380 the context of DECL. This is required for template substitution
1381 of `T' in the function parameter of `g' and template parameter
1382 of `h' in the above examples. Here ARGS corresponds to `int'. */
1389 {
1391 {
1394 else
1396 current_depth++;
1397 }
1399 }
1402 {
1404 tree friend_type;
1405 tree decl_type;
1406 tree friend_args_type;
1407 tree decl_args_type;
1409 /* Make sure that both DECL and FRIEND_DECL are templates or
1410 non-templates. */
1416 {
1417 /* If both are templates, check template parameter list. */
1418 tree friend_parms
1423 friend_parms))
1427 }
1428 else
1436 /* Check if return types match. */
1440 /* Check if function parameter types match, ignoring the
1441 `this' parameter. */
1450 }
1451 else
1452 {
1453 /* DECL is a TYPE_DECL */
1457 /* Make sure that both DECL and FRIEND_DECL are templates or
1458 non-templates. */
1459 is_template
1466 {
1467 tree friend_parms;
1468 /* If both are templates, check the name of the two
1469 TEMPLATE_DECL's first because is_friend didn't. */
1474 /* Now check template parameter list. */
1475 friend_parms
1478 return comp_template_parms
1480 friend_parms);
1481 }
1482 else
1485 }
1486 }
1488 }
1490 /* Register the specialization SPEC as a specialization of TMPL with
1491 the indicated ARGS. IS_FRIEND indicates whether the specialization
1492 is actually just a friend declaration. ATTRLIST is the list of
1493 attributes that the specialization is declared with or NULL when
1494 it isn't. Returns SPEC, or an equivalent prior declaration, if
1495 available.
1497 We also store instantiations of field packs in the hash table, even
1498 though they are not themselves templates, to make lookup easier. */
1500 static tree
1502 hashval_t hash)
1503 {
1504 tree fn;
1512 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1513 register it; we want the corresponding TEMPLATE_DECL instead.
1514 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1515 the more obvious `uses_template_parms (spec)' to avoid problems
1516 with default function arguments. In particular, given
1517 something like this:
1519 template <class T> void f(T t1, T t = T())
1521 the default argument expression is not substituted for in an
1522 instantiation unless and until it is actually needed. */
1525 spec_entry elt;
1536 else
1539 /* We can sometimes try to re-register a specialization that we've
1540 already got. In particular, regenerate_decl_from_template calls
1541 duplicate_decls which will update the specialization list. But,
1542 we'll still get called again here anyhow. It's more convenient
1543 to simply allow this than to try to prevent it. */
1547 {
1549 {
1552 {
1554 fn);
1556 }
1557 else
1558 {
1559 tree clone;
1560 /* This situation should occur only if the first
1561 specialization is an implicit instantiation, the
1562 second is an explicit specialization, and the
1563 implicit instantiation has not yet been used. That
1564 situation can occur if we have implicitly
1565 instantiated a member function and then specialized
1566 it later.
1568 We can also wind up here if a friend declaration that
1569 looked like an instantiation turns out to be a
1570 specialization:
1572 template <class T> void foo(T);
1573 class S { friend void foo<>(int) };
1574 template <> void foo(int);
1576 We transform the existing DECL in place so that any
1577 pointers to it become pointers to the updated
1578 declaration.
1580 If there was a definition for the template, but not
1581 for the specialization, we want this to look as if
1582 there were no definition, and vice versa. */
1586 /* The call to duplicate_decls will have applied
1587 [temp.expl.spec]:
1589 An explicit specialization of a function template
1590 is inline only if it is explicitly declared to be,
1591 and independently of whether its function template
1592 is.
1594 to the primary function; now copy the inline bits to
1595 the various clones. */
1597 {
1604 }
1608 }
1609 }
1611 {
1614 /* We've already complained in duplicate_decls. */
1618 /* Dup decl failed, but this is a new definition. Set the
1619 line number so any errors match this new
1620 definition. */
1624 }
1625 }
1629 /* A specialization must be declared in the same namespace as the
1630 template it is specializing. */
1643 /* If TMPL is a forward declaration of a template function, keep a list
1644 of all specializations in case we need to reassign them to a friend
1645 template later in tsubst_friend_function.
1647 Also keep a list of all variable template instantiations so that
1648 process_partial_specialization can check whether a later partial
1649 specialization would have used it. */
1654 }
1656 /* Restricts tree and type comparisons. */
1660 /* Returns true iff two spec_entry nodes are equivalent. */
1662 bool
1664 {
1673 /* tmpl could be a FIELD_DECL for a capture pack. */
1677 {
1678 /* Partial specializations of a variable template can be distinguished by
1679 constraints. */
1683 }
1689 }
1691 /* Returns a hash for a template TMPL and template arguments ARGS. */
1693 static hashval_t
1695 {
1698 }
1700 hashval_t
1702 {
1707 }
1709 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1710 ignoring SPEC. */
1712 hashval_t
1714 {
1716 }
1718 /* Recursively calculate a hash value for a template argument ARG, for use
1719 in the hash tables of template specializations. We must be
1720 careful to (at least) skip the same entities template_args_equal
1721 does. */
1723 hashval_t
1725 {
1730 /* Strip nop-like things, but not the same as STRIP_NOPS. */
1741 {
1743 /* Getting here with an ARGUMENT_PACK_SELECT means we're probably
1744 preserving it in a hash table, which is bad because it will change
1745 meaning when gen_elem_of_pack_expansion_instantiation changes the
1746 ARGUMENT_PACK_SELECT_INDEX. */
1780 {
1783 {
1786 }
1788 }
1792 {
1795 }
1806 val = iterative_hash_template_arg
1818 val);
1820 val);
1829 /* [temp.over.link] Two lambda-expressions are never considered
1830 equivalent.
1832 So just hash the closure type. */
1843 /* Now hash operands as usual. */
1847 {
1850 {
1854 }
1856 call_expr_arg_iterator ai;
1861 }
1865 }
1869 {
1872 {
1873 // We want an alias specialization that survived strip_typedefs
1874 // to hash differently from its TYPE_CANONICAL, to avoid hash
1875 // collisions that compare as different in template_args_equal.
1876 // These could be dependent specializations that strip_typedefs
1877 // left alone, or untouched specializations because
1878 // coerce_template_parms returns the unconverted template
1879 // arguments if it sees incomplete argument packs.
1882 }
1885 {
1892 {
1893 /* Hash the components that are relevant to TYPENAME_TYPE
1894 equivalence as determined by structural_comptypes. We
1895 can only coherently do this when comparing_specializations
1896 is set, because otherwise structural_comptypes tries
1897 resolving TYPENAME_TYPE via the current instantiation. */
1902 }
1909 }
1922 }
1923 }
1925 /* Unregister the specialization SPEC as a specialization of TMPL.
1926 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1927 if the SPEC was listed as a specialization of TMPL.
1929 Note that SPEC has been ggc_freed, so we can't look inside it. */
1931 bool
1933 {
1935 spec_entry elt;
1943 {
1948 }
1951 }
1953 /* Like register_specialization, but for local declarations. We are
1954 registering SPEC, an instantiation of TMPL. */
1956 void
1958 {
1961 }
1963 /* Registers T as a specialization of itself. This is used to preserve
1964 the references to already-parsed parameters when instantiating
1965 postconditions. */
1967 void
1969 {
1971 }
1973 /* TYPE is a class type. Returns true if TYPE is an explicitly
1974 specialized class. */
1976 bool
1978 {
1982 }
1984 /* Print the list of functions at FNS, going through all the overloads
1985 for each element of the list. Alternatively, FNS cannot be a
1986 TREE_LIST, in which case it will be printed together with all the
1987 overloads.
1989 MORE and *STR should respectively be FALSE and NULL when the function
1990 is called from the outside. They are used internally on recursive
1991 calls. print_candidates manages the two parameters and leaves NULL
1992 in *STR when it ends. */
1994 static void
1996 {
2000 else
2002 {
2008 {
2011 else
2014 }
2016 }
2017 }
2019 /* Print the list of candidate FNS in an error message. FNS can also
2020 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
2022 void
2024 {
2028 }
2030 /* Get a (possibly) constrained template declaration for the
2031 purpose of ordering candidates. */
2032 static tree
2034 {
2040 }
2042 /* Among candidates having the same signature, return the
2043 most constrained or NULL_TREE if there is no best candidate.
2044 If the signatures of candidates vary (e.g., template
2045 specialization vs. member function), then there can be no
2046 most constrained.
2048 Note that we don't compare constraints on the functions
2049 themselves, but rather those of their templates. */
2050 static tree
2052 {
2053 // Try to find the best candidate in a first pass.
2056 {
2063 }
2065 // Verify that the champ is better than previous candidates.
2070 }
2073 }
2076 /* Returns the template (one of the functions given by TEMPLATE_ID)
2077 which can be specialized to match the indicated DECL with the
2078 explicit template args given in TEMPLATE_ID. The DECL may be
2079 NULL_TREE if none is available. In that case, the functions in
2080 TEMPLATE_ID are non-members.
2082 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2083 specialization of a member template.
2085 The TEMPLATE_COUNT is the number of references to qualifying
2086 template classes that appeared in the name of the function. See
2087 check_explicit_specialization for a more accurate description.
2089 TSK indicates what kind of template declaration (if any) is being
2090 declared. TSK_TEMPLATE indicates that the declaration given by
2091 DECL, though a FUNCTION_DECL, has template parameters, and is
2092 therefore a template function.
2094 The template args (those explicitly specified and those deduced)
2095 are output in a newly created vector *TARGS_OUT.
2097 If it is impossible to determine the result, an error message is
2098 issued. The error_mark_node is returned to indicate failure. */
2100 static tree
2102 tree decl,
2106 tmpl_spec_kind tsk)
2107 {
2108 tree fns;
2109 tree targs;
2110 tree explicit_targs;
2113 /* A TREE_LIST of templates of which DECL may be a specialization.
2114 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2115 corresponding TREE_PURPOSE is the set of template arguments that,
2116 when used to instantiate the template, would produce a function
2117 with the signature of DECL. */
2127 /* We shouldn't be specializing a member template of an
2128 unspecialized class template; we already gave an error in
2129 check_specialization_scope, now avoid crashing. */
2133 {
2136 }
2144 /* Check for baselinks. */
2149 {
2153 }
2155 {
2158 }
2160 /* Count the number of template headers specified for this
2161 specialization. */
2172 {
2175 tf_warning_or_error);
2179 }
2181 {
2185 {
2186 tree decl_arg_types;
2187 tree fn_arg_types;
2189 /* In case of explicit specialization, we need to check if
2190 the number of template headers appearing in the specialization
2191 is correct. This is usually done in check_explicit_specialization,
2192 but the check done there cannot be exhaustive when specializing
2193 member functions. Consider the following code:
2195 template <> void A<int>::f(int);
2196 template <> template <> void A<int>::f(int);
2198 Assuming that A<int> is not itself an explicit specialization
2199 already, the first line specializes "f" which is a non-template
2200 member function, whilst the second line specializes "f" which
2201 is a template member function. So both lines are syntactically
2202 correct, and check_explicit_specialization does not reject
2203 them.
2205 Here, we can do better, as we are matching the specialization
2206 against the declarations. We count the number of template
2207 headers, and we check if they match TEMPLATE_COUNT + 1
2208 (TEMPLATE_COUNT is the number of qualifying template classes,
2209 plus there must be another header for the member template
2210 itself).
2212 Notice that if header_count is zero, this is not a
2213 specialization but rather a template instantiation, so there
2214 is no check we can perform here. */
2216 {
2219 }
2221 /* Check that the number of template arguments at the
2222 innermost level for DECL is the same as for FN. */
2230 /* DECL might be a specialization of FN. */
2234 /* For a non-static member function, we need to make sure
2235 that the const qualification is the same. Since
2236 get_bindings does not try to merge the "this" parameter,
2237 we must do the comparison explicitly. */
2239 {
2244 /* And the ref-qualification. */
2248 }
2250 /* Skip the "this" parameter and, for constructors of
2251 classes with virtual bases, the VTT parameter. A
2252 full specialization of a constructor will have a VTT
2253 parameter, but a template never will. */
2254 decl_arg_types
2256 fn_arg_types
2259 /* Function templates cannot be specializations; there are
2260 no partial specializations of functions. Therefore, if
2261 the type of DECL does not match FN, there is no
2262 match.
2264 Note that it should never be the case that we have both
2265 candidates added here, and for regular member functions
2266 below. */
2268 {
2270 current_template_parms))
2283 {
2284 /* C++20 CA104: Substitute directly into the
2285 constraint-expression. */
2291 }
2295 }
2297 /* See whether this function might be a specialization of this
2298 template. Suppress access control because we might be trying
2299 to make this specialization a friend, and we have already done
2300 access control for the declaration of the specialization. */
2306 /* We cannot deduce template arguments that when used to
2307 specialize TMPL will produce DECL. */
2311 /* We deduced something involving 'auto', which isn't a valid
2312 template argument. */
2315 /* Save this template, and the arguments deduced. */
2317 }
2319 /* FN is an ordinary member function, and we need a
2320 specialization of a member template. */
2321 ;
2323 /* We can get IDENTIFIER_NODEs here in certain erroneous
2324 cases. */
2325 ;
2327 /* This is just an ordinary non-member function. Nothing can
2328 be a specialization of that. */
2329 ;
2331 /* Cannot specialize functions that are created implicitly. */
2332 ;
2333 else
2334 {
2335 tree decl_arg_types;
2337 /* This is an ordinary member function. However, since
2338 we're here, we can assume its enclosing class is a
2339 template class. For example,
2341 template <typename T> struct S { void f(); };
2342 template <> void S<int>::f() {}
2344 Here, S<int>::f is a non-template, but S<int> is a
2345 template class. If FN has the same type as DECL, we
2346 might be in business. */
2349 /* Its enclosing class is an explicit specialization
2350 of a template class. This is not a candidate. */
2355 /* The return types differ. */
2358 /* Adjust the type of DECL in case FN is a static member. */
2365 decl_arg_types))
2373 // If the deduced arguments do not satisfy the constraints,
2374 // this is not a candidate.
2378 // Add the candidate.
2380 }
2381 }
2384 {
2385 /* We have:
2387 [temp.expl.spec]
2389 It is possible for a specialization with a given function
2390 signature to be instantiated from more than one function
2391 template. In such cases, explicit specification of the
2392 template arguments must be used to uniquely identify the
2393 function template specialization being specialized.
2395 Note that here, there's no suggestion that we're supposed to
2396 determine which of the candidate templates is most
2397 specialized. However, we, also have:
2399 [temp.func.order]
2401 Partial ordering of overloaded function template
2402 declarations is used in the following contexts to select
2403 the function template to which a function template
2404 specialization refers:
2406 -- when an explicit specialization refers to a function
2407 template.
2409 So, we do use the partial ordering rules, at least for now.
2410 This extension can only serve to make invalid programs valid,
2411 so it's safe. And, there is strong anecdotal evidence that
2412 the committee intended the partial ordering rules to apply;
2413 the EDG front end has that behavior, and John Spicer claims
2414 that the committee simply forgot to delete the wording in
2415 [temp.expl.spec]. */
2418 {
2421 }
2422 }
2424 // Concepts allows multiple declarations of member functions
2425 // with the same signature. Like above, we need to rely on
2426 // on the partial ordering of those candidates to determine which
2427 // is the best.
2429 {
2431 {
2434 }
2435 }
2438 {
2443 "saw %d %<template<>%>, need %d for "
2448 }
2452 {
2458 }
2460 /* We have one, and exactly one, match. */
2462 {
2466 /* Propagate the candidate's constraints to the declaration. */
2470 /* DECL is a re-declaration or partial instantiation of a template
2471 function. */
2474 /* It was a specialization of an ordinary member function in a
2475 template class. */
2477 }
2479 /* It was a specialization of a template. */
2483 /* Propagate the template's constraints to the declaration. */
2488 }
2490 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2491 but with the default argument values filled in from those in the
2492 TMPL_TYPES. */
2494 static tree
2496 tree tmpl_types)
2497 {
2498 tree new_spec_types;
2506 /* Substitute into the rest of the list. */
2507 new_spec_types =
2511 /* Add the default argument for this parameter. */
2514 new_spec_types);
2515 }
2517 /* DECL is an explicit specialization. Replicate default arguments
2518 from the template it specializes. (That way, code like:
2520 template <class T> void f(T = 3);
2521 template <> void f(double);
2522 void g () { f (); }
2524 works, as required.) An alternative approach would be to look up
2525 the correct default arguments at the call-site, but this approach
2526 is consistent with how implicit instantiations are handled. */
2528 static void
2530 {
2531 tree tmpl;
2532 tree spec_types;
2533 tree tmpl_types;
2534 tree new_spec_types;
2535 tree old_type;
2536 tree new_type;
2537 tree t;
2542 /* See if there's anything we need to do. */
2555 {
2556 /* Remove the this pointer, but remember the object's type for
2557 CV quals. */
2563 {
2564 /* DECL may contain more parameters than TMPL due to the extra
2565 in-charge parameter in constructors and destructors. */
2568 }
2570 {
2573 }
2574 }
2576 /* Compute the merged default arguments. */
2577 new_spec_types =
2580 /* Compute the new FUNCTION_TYPE. */
2582 {
2586 new_spec_types);
2589 /* Put the in-charge parameter back. */
2592 new_spec_types);
2596 new_spec_types);
2597 }
2598 else
2600 new_spec_types);
2606 }
2608 /* Return the number of template headers we expect to see for a definition
2609 or specialization of CTYPE or one of its non-template members. */
2611 int
2613 {
2617 {
2618 /* You're supposed to have one `template <...>' for every
2619 template class, but you don't need one for a full
2620 specialization. For example:
2622 template <class T> struct S{};
2623 template <> struct S<int> { void f(); };
2624 void S<int>::f () {}
2626 is correct; there shouldn't be a `template <>' for the
2627 definition of `S<int>::f'. */
2629 /* If CTYPE does not have template information of any
2630 kind, then it is not a template, nor is it nested
2631 within a template. */
2639 }
2642 }
2644 /* Do a simple sanity check on the template headers that precede the
2645 variable declaration DECL. */
2647 void
2649 {
2654 {
2657 "variable templates only available with "
2660 // Namespace-scope variable templates should have a template header.
2662 }
2664 {
2665 auto_diagnostic_group d;
2667 "too many template headers for %qD "
2673 "members of an explicitly specialized class are defined "
2675 }
2676 }
2678 /* An explicit specialization whose declarator-id or class-head-name is not
2679 qualified shall be declared in the nearest enclosing namespace of the
2680 template, or, if the namespace is inline (7.3.1), any namespace from its
2681 enclosing namespace set.
2683 If the name declared in the explicit instantiation is an unqualified name,
2684 the explicit instantiation shall appear in the namespace where its template
2685 is declared or, if that namespace is inline (7.3.1), any namespace from its
2686 enclosing namespace set. */
2688 void
2690 {
2695 {
2701 /* This was allowed in C++98, so only pedwarn. */
2703 "outside its namespace must use a nested-name-"
2705 }
2706 }
2708 /* Warn for a template specialization SPEC that is missing some of a set
2709 of function or type attributes that the template TEMPL is declared with.
2710 ATTRLIST is a list of additional attributes that SPEC should be taken
2711 to ultimately be declared with. */
2713 static void
2715 {
2719 /* Avoid warning if the difference between the primary and
2720 the specialization is not in one of the attributes below. */
2724 };
2726 /* Put together a list of the black listed attributes that the primary
2727 template is declared with that the specialization is not, in case
2728 it's not apparent from the most recent declaration of the primary. */
2729 pretty_printer str;
2736 auto_diagnostic_group d;
2739 spec))
2745 }
2747 /* Check to see if the function just declared, as indicated in
2748 DECLARATOR, and in DECL, is a specialization of a function
2749 template. We may also discover that the declaration is an explicit
2750 instantiation at this point.
2752 Returns DECL, or an equivalent declaration that should be used
2753 instead if all goes well. Issues an error message if something is
2754 amiss. Returns error_mark_node if the error is not easily
2755 recoverable.
2757 FLAGS is a bitmask consisting of the following flags:
2759 2: The function has a definition.
2760 4: The function is a friend.
2762 The TEMPLATE_COUNT is the number of references to qualifying
2763 template classes that appeared in the name of the function. For
2764 example, in
2766 template <class T> struct S { void f(); };
2767 void S<int>::f();
2769 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2770 classes are not counted in the TEMPLATE_COUNT, so that in
2772 template <class T> struct S {};
2773 template <> struct S<int> { void f(); }
2774 template <> void S<int>::f();
2776 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2777 invalid; there should be no template <>.)
2779 If the function is a specialization, it is marked as such via
2780 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2781 is set up correctly, and it is added to the list of specializations
2782 for that template. */
2784 tree
2786 tree decl,
2789 tree attrlist)
2790 {
2799 tmpl_spec_kind tsk;
2802 {
2805 else
2807 }
2808 else
2812 {
2815 {
2818 }
2822 {
2824 /* This could be something like:
2826 template <class T> void f(T);
2827 class S { friend void f<>(int); } */
2829 else
2830 {
2831 /* This case handles bogus declarations like template <>
2832 template <class T> void f<int>(); */
2836 declarator);
2838 }
2839 }
2843 /* The error has already been reported in
2844 check_specialization_scope. */
2850 /* Fall through. */
2863 decl);
2866 else
2870 /* Fall through. */
2876 /* In cases like template<> constexpr bool v = true;
2877 We'll give an error in check_template_variable. */
2883 else
2889 {
2890 /* This case handles bogus declarations like template <>
2891 template <class T> void f<int>(); */
2896 declarator);
2898 {
2899 /* Partial specialization of variable template. */
2903 }
2906 "non-type partial specialization %qE "
2908 else
2910 "non-class, non-variable partial specialization %qE "
2913 ok:;
2914 }
2917 /* This is a specialization of a member template, without
2918 specialization the containing class. Something like:
2920 template <class T> struct S {
2921 template <class U> void f (U);
2922 };
2923 template <> template <class U> void S<int>::f(U) {}
2925 That's a specialization -- but of the entire template. */
2931 }
2934 /* This doesn't apply to variable templates. */
2936 {
2940 {
2944 }
2945 }
2948 {
2954 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2956 {
2957 tree fns;
2962 else
2963 {
2964 /* If there is no class context, the explicit instantiation
2965 must be at namespace scope. */
2968 /* Find the namespace binding, using the declaration
2969 context. */
2973 {
2974 /* If lookup fails, look for a friend declaration so we can
2975 give a better diagnostic. */
2976 fns = (lookup_qualified_name
2981 }
2984 {
2987 }
2988 }
2991 }
2997 {
2999 /* A specialization in class scope. This is invalid,
3000 but the error will already have been flagged by
3001 check_specialization_scope. */
3003 else
3004 {
3005 /* It's not valid to write an explicit instantiation in
3006 class scope, e.g.:
3008 class C { template void f(); }
3010 This case is caught by the parser. However, on
3011 something like:
3013 template class C { void f(); };
3015 (which is invalid) we can get here. The error will be
3016 issued later. */
3017 ;
3018 }
3021 }
3024 {
3025 // We'll match variable templates in start_decl.
3029 /* Find the list of functions in ctype that have the same
3030 name as the declared function. */
3034 {
3038 {
3039 /* From [temp.expl.spec]:
3041 If such an explicit specialization for the member
3042 of a class template names an implicitly-declared
3043 special member function (clause _special_), the
3044 program is ill-formed.
3046 Similar language is found in [temp.explicit]. */
3049 }
3052 }
3054 /* For a type-conversion operator, We might be looking for
3055 `operator int' which will be a specialization of
3056 `operator T'. Grab all the conversion operators, and
3057 then select from them. */
3062 {
3065 }
3066 else
3068 }
3070 /* Figure out what exactly is being specialized at this point.
3071 Note that for an explicit instantiation, even one for a
3072 member function, we cannot tell a priori whether the
3073 instantiation is for a member template, or just a member
3074 function of a template class. Even if a member template is
3075 being instantiated, the member template arguments may be
3076 elided if they can be deduced from the rest of the
3077 declaration. */
3080 member_specialization,
3081 template_count,
3082 tsk);
3085 /* We couldn't figure out what this declaration was
3086 specializing. */
3088 else
3089 {
3091 {
3092 auto_diagnostic_group d;
3094 "friend declaration %qD is not visible to "
3098 }
3107 {
3108 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3109 is done by do_decl_instantiation later. */
3115 {
3116 /* If TMPL is not the most general template (for
3117 example, if TMPL is a friend template that is
3118 injected into namespace scope), then there will
3119 be too many levels of TARGS. Remove some of them
3120 here. */
3122 tree new_targs;
3129 }
3132 }
3134 /* If we thought that the DECL was a member function, but it
3135 turns out to be specializing a static member function,
3136 make DECL a static member function as well. */
3142 /* If this is a specialization of a member template of a
3143 template class, we want to return the TEMPLATE_DECL, not
3144 the specialization of it. */
3146 {
3151 {
3152 tree parm;
3156 /* We want to use the argument list specified in the
3157 definition, not in the original declaration. */
3162 }
3167 }
3169 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3175 /* Inherit default function arguments from the template
3176 DECL is specializing. */
3180 /* This specialization has the same protection as the
3181 template it specializes. */
3185 /* 7.1.1-1 [dcl.stc]
3187 A storage-class-specifier shall not be specified in an
3188 explicit specialization...
3190 The parser rejects these, so unless action is taken here,
3191 explicit function specializations will always appear with
3192 global linkage.
3194 The action recommended by the C++ CWG in response to C++
3195 defect report 605 is to make the storage class and linkage
3196 of the explicit specialization match the templated function:
3198 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3199 */
3201 {
3205 /* A concept cannot be specialized. */
3207 {
3209 gen_tmpl);
3211 }
3213 /* This specialization has the same linkage and visibility as
3214 the function template it specializes. */
3217 {
3220 }
3223 {
3226 }
3227 }
3229 /* If DECL is a friend declaration, declared using an
3230 unqualified name, the namespace associated with DECL may
3231 have been set incorrectly. For example, in:
3233 template <typename T> void f(T);
3234 namespace N {
3235 struct S { friend void f<int>(int); }
3236 }
3238 we will have set the DECL_CONTEXT for the friend
3239 declaration to N, rather than to the global namespace. */
3244 /* This is not really a declaration of a specialization.
3245 It's just the name of an instantiation. But, it's not
3246 a request for an instantiation, either. */
3249 /* A specialization is not necessarily COMDAT. */
3255 /* If this is a full specialization, register it so that we can find
3256 it again. Partial specializations will be registered in
3257 process_partial_specialization. */
3259 {
3264 }
3266 /* If this is a specialization, splice any contracts that may have
3267 been inherited from the template, removing them. */
3271 /* A 'structor should already have clones. */
3277 }
3278 }
3281 }
3283 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3284 parameters. These are represented in the same format used for
3285 DECL_TEMPLATE_PARMS. */
3287 int
3289 {
3290 const_tree p1;
3291 const_tree p2;
3299 {
3311 {
3315 /* If either of the template parameters are invalid, assume
3316 they match for the sake of error recovery. */
3329 }
3330 }
3333 /* One set of parameters has more parameters lists than the
3334 other. */
3338 }
3340 /* Returns true if two template parameters are declared with
3341 equivalent constraints. */
3343 static bool
3345 {
3353 }
3355 /* Returns true when two template parameters are equivalent. */
3357 static bool
3359 {
3363 /* If either of the template parameters are invalid, assume
3364 they match for the sake of error recovery. */
3368 /* ... they declare parameters of the same kind. */
3372 /* ... one parameter was introduced by a parameter declaration, then
3373 both are. This case arises as a result of eagerly rewriting declarations
3374 during parsing. */
3378 /* ... if either declares a pack, they both do. */
3383 {
3384 /* ... if they declare non-type parameters, the types are equivalent. */
3387 }
3389 {
3390 /* ... if they declare template template parameters, their template
3391 parameter lists are equivalent. */
3394 }
3396 /* ... if they are declared with a qualified-concept name, they both
3397 are, and those names are equivalent. */
3399 }
3401 /* Returns true if two template parameters lists are equivalent.
3402 Two template parameter lists are equivalent if they have the
3403 same length and their corresponding parameters are equivalent.
3405 PARMS1 and PARMS2 are TREE_LISTs containing TREE_VECs: the
3406 data structure returned by DECL_TEMPLATE_PARMS.
3408 This is generally the same implementation as comp_template_parms
3409 except that it also the concept names and arguments used to
3410 introduce parameters. */
3412 static bool
3414 {
3421 {
3429 {
3434 }
3438 }
3444 }
3446 /* Return true if the requires-clause of the template parameter lists are
3447 equivalent and false otherwise. */
3448 static bool
3450 {
3458 }
3460 /* Returns true if two template heads are equivalent. 17.6.6.1p6:
3461 Two template heads are equivalent if their template parameter
3462 lists are equivalent and their requires clauses are equivalent.
3464 In pre-C++20, this is equivalent to calling comp_template_parms
3465 for the template parameters of TMPL1 and TMPL2. */
3467 bool
3469 {
3473 /* Don't change the matching rules for pre-C++20. */
3477 /* ... have the same number of template parameters, and their
3478 corresponding parameters are equivalent. */
3482 /* ... if either has a requires-clause, they both do and their
3483 corresponding constraint-expressions are equivalent. */
3485 }
3487 /* Determine whether PARM is a parameter pack. */
3489 bool
3491 {
3492 /* Determine if we have a non-type template parameter pack. */
3499 /* If this is a list of template parameters, we could get a
3500 TYPE_DECL or a TEMPLATE_DECL. */
3504 /* Otherwise it must be a type template parameter. */
3508 }
3510 /* Determine if T is a function parameter pack. */
3512 bool
3514 {
3518 }
3520 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3521 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3523 tree
3525 {
3532 }
3534 /* Return true iff the function parameter PARAM_DECL was expanded
3535 from the function parameter pack PACK. */
3537 bool
3539 {
3544 /* The parameter pack and its pack arguments have the same
3545 DECL_PARM_INDEX. */
3547 }
3549 /* Determine whether ARGS describes a variadic template args list,
3550 i.e., one that is terminated by a template argument pack. */
3552 static bool
3554 {
3556 tree last_parm;
3570 }
3572 /* Generate a new name for the parameter pack name NAME (an
3573 IDENTIFIER_NODE) that incorporates its */
3575 static tree
3577 {
3578 /* Munge the name to include the parameter index. */
3579 #define NUMBUF_LEN 128
3593 }
3595 /* Return true if T is a primary function, class or alias template
3596 specialization, not including the template pattern. */
3598 bool
3600 {
3616 }
3618 /* Return true if PARM is a template template parameter. */
3620 bool
3622 {
3624 }
3626 /* Return true iff PARM is a DECL representing a type template
3627 parameter. */
3629 bool
3631 {
3636 }
3638 /* Return the template parameters of T if T is a
3639 primary template instantiation, NULL otherwise. */
3641 tree
3643 {
3648 parms = INNERMOST_TEMPLATE_PARMS
3652 }
3654 /* Returns the template arguments of T if T is a template instantiation,
3655 NULL otherwise. */
3657 tree
3659 {
3667 }
3669 /* Return the argument pack elements of T if T is a template argument pack,
3670 NULL otherwise. */
3672 tree
3674 {
3680 }
3682 /* In an ARGUMENT_PACK_SELECT, the actual underlying argument that the
3683 ARGUMENT_PACK_SELECT represents. */
3685 static tree
3687 {
3691 /* If the selected argument is an expansion E, that most likely means we were
3692 called from gen_elem_of_pack_expansion_instantiation during the
3693 substituting of an argument pack (of which the Ith element is a pack
3694 expansion, where I is ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
3695 In this case, the Ith element resulting from this substituting is going to
3696 be a pack expansion, which pattern is the pattern of E. Let's return the
3697 pattern of E, and gen_elem_of_pack_expansion_instantiation will build the
3698 resulting pack expansion from it. */
3700 {
3701 /* Make sure we aren't throwing away arg info. */
3704 }
3707 }
3709 /* Return a modification of ARGS that's suitable for preserving inside a hash
3710 table. In particular, this replaces each ARGUMENT_PACK_SELECT with its
3711 underlying argument. ARGS is copied (upon modification) iff COW_P. */
3713 static tree
3715 {
3720 {
3722 tree r;
3729 else
3732 {
3734 {
3737 }
3739 }
3740 }
3743 }
3745 /* True iff FN is a function representing a built-in variadic parameter
3746 pack. */
3748 bool
3750 {
3760 }
3762 /* True iff CALL is a call to a function representing a built-in variadic
3763 parameter pack. */
3765 static bool
3767 {
3771 }
3773 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3775 static tree
3777 tree in_decl)
3778 {
3783 {
3785 {
3788 }
3793 }
3794 else
3795 {
3800 /* Calculate the largest value of len that won't make the size of the vec
3801 overflow an int. The compiler will exceed resource limits long before
3802 this, but it seems a decent place to diagnose. */
3806 {
3810 max);
3812 }
3820 }
3821 }
3823 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3824 CALL. */
3826 static tree
3828 tree in_decl)
3829 {
3839 }
3841 /* Return true if the tree T has the extra args mechanism for
3842 avoiding partial instantiation. */
3844 static bool
3846 {
3851 }
3853 /* Structure used to track the progress of find_parameter_packs_r. */
3854 struct find_parameter_pack_data
3855 {
3856 /* TREE_LIST that will contain all of the parameter packs found by
3857 the traversal. */
3860 /* Set of AST nodes that have been visited by the traversal. */
3863 /* True iff we're making a type pack expansion. */
3866 /* True iff we found a subtree that has the extra args mechanism. */
3868 };
3870 /* Identifies all of the argument packs that occur in a template
3871 argument and appends them to the TREE_LIST inside DATA, which is a
3872 find_parameter_pack_data structure. This is a subroutine of
3873 make_pack_expansion and uses_parameter_packs. */
3874 static tree
3876 {
3882 #define WALK_SUBTREE(NODE) \
3883 cp_walk_tree (&(NODE), &find_parameter_packs_r, \
3884 ppd, ppd->visited) \
3886 /* Don't look through typedefs; we are interested in whether a
3887 parameter pack is actually written in the expression/type we're
3888 looking at, not the target type. */
3890 {
3891 /* But do look at arguments for an alias template. */
3898 }
3900 /* Identify whether this is a parameter pack or not. */
3902 {
3910 /* FALLTHRU */
3912 /* If the placeholder appears in the decl-specifier-seq of a function
3913 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3914 is a pack expansion, the invented template parameter is a template
3915 parameter pack. */
3925 {
3926 /* We don't want to walk into the type of a PARM_DECL,
3927 because we don't want to see the type parameter pack. */
3930 }
3935 {
3936 /* We don't want to walk into the type of a variadic capture proxy,
3937 because we don't want to see the type parameter pack. */
3940 }
3942 {
3944 find_parameter_packs_r,
3947 }
3959 /* Not a parameter pack. */
3961 }
3964 {
3965 /* Add this parameter pack to the list. */
3967 }
3976 /* This switch statement will return immediately if we don't find a
3977 parameter pack. ??? Should some of these be in cp_walk_subtrees? */
3979 {
3981 /* Check the template itself. */
3987 {
3989 /* Ignore the declaration of a capture proxy for a parameter pack. */
3993 /* Since we stop at typedefs above, we need to look through them at
3994 the point of the DECL_EXPR. */
3998 }
4025 {
4026 /* Since we defer implicit capture, look in the parms and body. */
4033 }
4036 {
4037 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
4038 type_pack_expansion_p to false so that any placeholders
4039 within the expression don't get marked as parameter packs. */
4047 }
4056 /* Don't walk into IF_STMT_EXTRA_ARGS. */
4063 {
4064 /* Local class, need to look through the whole definition.
4065 TYPE_BINFO might be unset for a partial instantiation. */
4070 }
4071 else
4072 /* Enum, look at the values. */
4086 }
4088 #undef WALK_SUBTREE
4091 }
4093 /* Determines if the expression or type T uses any parameter packs. */
4094 tree
4096 {
4105 }
4107 /* Turn ARG, which may be an expression, type, or a TREE_LIST
4108 representation a base-class initializer into a parameter pack
4109 expansion. If all goes well, the resulting node will be an
4110 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
4111 respectively. */
4112 tree
4114 {
4115 tree result;
4124 {
4125 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
4126 class initializer. In this case, the TREE_PURPOSE will be a
4127 _TYPE node (representing the base class expansion we're
4128 initializing) and the TREE_VALUE will be a TREE_LIST
4129 containing the initialization arguments.
4131 The resulting expansion looks somewhat different from most
4132 expansions. Rather than returning just one _EXPANSION, we
4133 return a TREE_LIST whose TREE_PURPOSE is a
4134 TYPE_PACK_EXPANSION containing the bases that will be
4135 initialized. The TREE_VALUE will be identical to the
4136 original TREE_VALUE, which is a list of arguments that will
4137 be passed to each base. We do not introduce any new pack
4138 expansion nodes into the TREE_VALUE (although it is possible
4139 that some already exist), because the TREE_PURPOSE and
4140 TREE_VALUE all need to be expanded together with the same
4141 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
4142 resulting TREE_PURPOSE will mention the parameter packs in
4143 both the bases and the arguments to the bases. */
4144 tree purpose;
4145 tree value;
4148 /* Determine which parameter packs will be used by the base
4149 class expansion. */
4158 {
4161 arg);
4164 }
4167 {
4168 /* Collect the sets of parameter packs used in each of the
4169 initialization arguments. */
4171 {
4172 /* Determine which parameter packs will be expanded in this
4173 argument. */
4176 }
4177 }
4181 /* Create the pack expansion type for the base type. */
4187 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4188 they will rarely be compared to anything. */
4192 }
4197 /* Build the PACK_EXPANSION_* node. */
4198 result = for_types
4203 {
4204 /* Propagate type and const-expression information. */
4207 /* Mark this read now, since the expansion might be length 0. */
4209 }
4210 else
4211 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4212 they will rarely be compared to anything. */
4215 /* Determine which parameter packs will be expanded. */
4222 /* Make sure we found some parameter packs. */
4224 {
4226 {
4229 else
4231 }
4233 }
4238 /* If the pattern of this pack expansion contains a subtree that has
4239 the extra args mechanism for avoiding partial instantiation, then
4240 force this pack expansion to also use extra args. Otherwise
4241 partial instantiation of this pack expansion may not lower the
4242 level of some parameter packs within the pattern, which would
4243 confuse tsubst_pack_expansion later (PR101764). */
4247 }
4249 /* Checks T for any "bare" parameter packs, which have not yet been
4250 expanded, and issues an error if any are found. This operation can
4251 only be done on full expressions or types (e.g., an expression
4252 statement, "if" condition, etc.), because we could have expressions like:
4254 foo(f(g(h(args)))...)
4256 where "args" is a parameter pack. check_for_bare_parameter_packs
4257 should not be called for the subexpressions args, h(args),
4258 g(h(args)), or f(g(h(args))), because we would produce erroneous
4259 error messages.
4261 Returns TRUE and emits an error if there were bare parameter packs,
4262 returns FALSE otherwise. */
4263 bool
4265 {
4287 /* It's OK for a lambda to have an unexpanded parameter pack from the
4288 containing context, but do complain about unexpanded capture packs. */
4294 {
4295 /* We're in a lambda, but it isn't the innermost class.
4296 This should work, but currently doesn't. */
4299 }
4304 {
4310 }
4313 {
4316 {
4327 else
4332 else
4336 }
4339 }
4342 }
4344 /* Expand any parameter packs that occur in the template arguments in
4345 ARGS. */
4346 tree
4348 {
4357 /* First, determine if we need to expand anything, and the number of
4358 slots we'll need. */
4360 {
4365 {
4369 else
4371 }
4372 else
4373 {
4375 num_result_args++;
4376 }
4377 }
4379 /* If no expansion is necessary, we're done. */
4383 /* Expand arguments. */
4386 non_default_args_count =
4389 {
4392 {
4399 }
4400 else
4401 {
4404 }
4405 }
4409 }
4411 /* Checks if DECL shadows a template parameter.
4413 [temp.local]: A template-parameter shall not be redeclared within its
4414 scope (including nested scopes).
4416 Emits an error and returns TRUE if the DECL shadows a parameter,
4417 returns FALSE otherwise. */
4419 bool
4421 {
4422 tree olddecl;
4424 /* If we're not in a template, we can't possibly shadow a template
4425 parameter. */
4429 /* Figure out what we're shadowing. */
4433 /* If there's no previous binding for this name, we're not shadowing
4434 anything, let alone a template parameter. */
4438 /* If we're not shadowing a template parameter, we're done. Note
4439 that OLDDECL might be an OVERLOAD (or perhaps even an
4440 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4441 node. */
4445 /* We check for decl != olddecl to avoid bogus errors for using a
4446 name inside a class. We check TPFI to avoid duplicate errors for
4447 inline member templates. */
4453 /* Don't complain about the injected class name, as we've already
4454 complained about the class itself. */
4461 else
4466 }
4468 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4469 ORIG_LEVEL, DECL, and TYPE. */
4471 static tree
4475 tree decl,
4476 tree type)
4477 {
4488 }
4491 {
4493 {
4503 }
4506 {
4511 }
4512 };
4516 /* Find the canonical type parameter for the given template type
4517 parameter. Returns the canonical type parameter, which may be TYPE
4518 if no such parameter existed. */
4520 tree
4522 {
4530 }
4532 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4533 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4534 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4535 new one is created. */
4537 static tree
4539 tsubst_flags_t complain)
4540 {
4545 {
4550 type);
4565 /* Template template parameters need this. */
4568 {
4575 }
4577 /* Attach the TPI to the decl. */
4580 else
4582 }
4585 }
4587 /* Process information from new template parameter PARM and append it
4588 to the LIST being built. This new parameter is a non-type
4589 parameter iff IS_NON_TYPE is true. This new parameter is a
4590 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4591 is in PARM_LOC. */
4593 tree
4596 {
4602 {
4612 }
4619 {
4625 {
4626 /* [temp.param]
4628 The top-level cv-qualifiers on the template-parameter are
4629 ignored when determining its type. */
4634 && !is_parameter_pack
4635 /* If we're in a nested template parameter list, the template
4636 template parameter could be a parameter pack. */
4638 {
4639 /* This template parameter is not a parameter pack, but it
4640 should be. Complain about "bare" parameter packs. */
4643 /* Recover by calling this a parameter pack. */
4645 }
4646 }
4648 /* A template parameter is not modifiable. */
4657 current_template_depth,
4662 }
4663 else
4664 {
4665 tree t;
4669 {
4671 /* This is for distinguishing between real templates and template
4672 template parameters */
4675 /* any_template_parm_r expects to be able to get the targs of a
4676 DECL_TEMPLATE_RESULT. */
4685 }
4686 else
4687 {
4689 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4692 }
4699 current_template_depth,
4703 }
4711 /* Build requirements for the type/template parameter.
4712 This must be done after SET_DECL_TEMPLATE_PARM_P or
4713 process_template_parm could fail. */
4720 /* Build the parameter node linking the parameter declaration,
4721 its default argument (if any), and its constraints (if any). */
4727 else
4731 }
4733 /* The end of a template parameter list has been reached. Process the
4734 tree list into a parameter vector, converting each parameter into a more
4735 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4736 as PARM_DECLs. */
4738 tree
4740 {
4743 /* Pop the dummy parameter level and add the real one. We do not
4744 morph the dummy parameter in place, as it might have been
4745 captured by a (nested) template-template-parm. */
4748 current_template_parms
4753 {
4759 }
4764 }
4766 // Explicitly indicate the end of the template parameter list. We assume
4767 // that the current template parameters have been constructed and/or
4768 // managed explicitly, as when creating new template template parameters
4769 // from a shorthand constraint.
4770 void
4772 {
4774 }
4776 /* end_template_decl is called after a template declaration is seen. */
4778 void
4780 {
4786 /* This matches the pushlevel in begin_template_parm_list. */
4791 }
4793 /* Takes a TEMPLATE_PARM_P or DECL_TEMPLATE_PARM_P node or a TREE_LIST
4794 thereof, and converts it into an argument suitable to be passed to
4795 the type substitution functions. Note that if the TREE_LIST contains
4796 an error_mark node, the returned argument is error_mark_node. */
4798 tree
4800 {
4811 {
4815 else
4817 }
4823 {
4825 {
4826 /* Turn this argument into a TYPE_ARGUMENT_PACK
4827 with a single element, which expands T. */
4836 }
4837 }
4838 else
4839 {
4841 {
4842 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4843 with a single element, which expands T. */
4853 }
4854 else
4856 }
4858 }
4860 /* If T looks like a generic template argument produced by template_parm_to_arg,
4861 return the corresponding template parameter, otherwise return NULL_TREE. */
4863 static tree
4865 {
4870 {
4875 }
4882 else
4884 }
4886 /* Given a single level of template parameters (a TREE_VEC), return it
4887 as a set of template arguments. */
4889 tree
4891 {
4901 }
4903 /* Given a set of template parameters, return them as a set of template
4904 arguments. The template parameters are represented as a TREE_VEC, in
4905 the form documented in cp-tree.h for template arguments. */
4907 tree
4909 {
4910 tree header;
4915 /* If there is only one level of template parameters, we do not
4916 create a TREE_VEC of TREE_VECs. Instead, we return a single
4917 TREE_VEC containing the arguments. */
4922 {
4927 else
4929 }
4932 }
4934 /* Within the declaration of a template, return the currently active
4935 template parameters as an argument TREE_VEC. */
4937 static tree
4939 {
4941 }
4943 /* Return the fully generic arguments for of TMPL, i.e. what
4944 current_template_args would be while parsing it. */
4946 tree
4948 {
4953 /* DECL_TEMPLATE_RESULT doesn't have the arguments we want. For a template
4954 template parameter, it has no TEMPLATE_INFO; for a partial
4955 specialization, it has the arguments for the primary template, and we
4961 }
4963 /* Return the template arguments corresponding to the template parameters of
4964 TMPL's enclosing scope. When TMPL is a member of a partial specialization,
4965 this returns the arguments for the partial specialization as opposed to those
4966 for the primary template, which is the main difference between this function
4967 and simply using e.g. the TYPE_TI_ARGS of TMPL's DECL_CONTEXT. */
4969 tree
4971 {
4981 }
4983 /* Update the declared TYPE by doing any lookups which were thought to be
4984 dependent, but are not now that we know the SCOPE of the declarator. */
4986 tree
4988 {
4999 /* Don't bother building up the args in this case. */
5001 {
5002 /* tsubst in the args corresponding to the template parameters,
5003 including auto if present. Most things will be unchanged, but
5004 make_typename_type and tsubst_qualified_id will resolve
5005 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
5008 tree pushed;
5010 {
5014 }
5019 }
5025 {
5028 else
5030 }
5032 }
5034 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
5035 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
5036 the new template is a member template. */
5038 static tree
5040 {
5052 /* Propagate module information from the decl. */
5056 }
5058 struct template_parm_data
5059 {
5060 /* The level of the template parameters we are currently
5061 processing. */
5064 /* The index of the specialization argument we are currently
5065 processing. */
5068 /* An array whose size is the number of template parameters. The
5069 elements are nonzero if the parameter has been used in any one
5070 of the arguments processed so far. */
5073 /* An array whose size is the number of template arguments. The
5074 elements are nonzero if the argument makes use of template
5075 parameters of this level. */
5077 };
5079 /* Subroutine of push_template_decl used to see if each template
5080 parameter in a partial specialization is used in the explicit
5081 argument list. If T is of the LEVEL given in DATA (which is
5082 treated as a template_parm_data*), then DATA->PARMS is marked
5083 appropriately. */
5085 static int
5087 {
5095 {
5098 }
5100 /* In C++17 the type of a non-type argument is a deduced context. */
5105 data,
5106 NULL,
5109 /* Return zero so that for_each_template_parm will continue the
5110 traversal of the tree; we want to mark *every* template parm. */
5112 }
5114 /* Process the partial specialization DECL. */
5116 static tree
5118 {
5125 tree inner_parms;
5126 tree inst;
5136 /* A concept cannot be specialized. */
5138 {
5141 }
5146 /* We check that each of the template parameters given in the
5147 partial specialization is used in the argument list to the
5148 specialization. For example:
5150 template <class T> struct S;
5151 template <class T> struct S<T*>;
5153 The second declaration is OK because `T*' uses the template
5154 parameter T, whereas
5156 template <class T> struct S<int>;
5158 is no good. Even trickier is:
5160 template <class T>
5161 struct S1
5162 {
5163 template <class U>
5164 struct S2;
5165 template <class U>
5166 struct S2<T>;
5167 };
5169 The S2<T> declaration is actually invalid; it is a
5170 full-specialization. Of course,
5172 template <class U>
5173 struct S2<T (*)(U)>;
5175 or some such would have been OK. */
5183 {
5188 NULL,
5190 }
5193 {
5194 /* One of the template parms was not used in a deduced context in the
5195 specialization. */
5197 {
5201 }
5205 }
5210 /* [temp.class.spec]
5212 The argument list of the specialization shall not be identical to
5213 the implicit argument list of the primary template. */
5214 tree main_args
5217 && (!flag_concepts
5219 {
5222 "any template arguments; to define the primary template, "
5224 else
5226 "template arguments and is not more constrained than "
5227 "the primary template; to define the primary template, "
5230 }
5232 /* A partial specialization that replaces multiple parameters of the
5233 primary template with a pack expansion is less specialized for those
5234 parameters. */
5236 {
5238 "primary template because it replaces multiple parameters "
5241 /* Avoid crash in process_partial_specialization. */
5243 }
5246 {
5249 /* Avoid crash below. */
5251 }
5253 /* If we aren't in a dependent class, we can actually try deduction. */
5255 /* FIXME we should be able to handle a partial specialization of a
5256 partial instantiation, but currently we can't (c++/41727). */
5259 {
5260 auto_diagnostic_group d;
5263 decl))
5265 maintmpl);
5266 }
5268 /* [temp.spec.partial]
5270 The type of a template parameter corresponding to a specialized
5271 non-type argument shall not be dependent on a parameter of the
5272 specialization.
5274 Also, we verify that pack expansions only occur at the
5275 end of the argument list. */
5278 {
5285 {
5286 /* Extract the arguments from the argument pack. We'll be
5287 iterating over these in the following loop. */
5290 }
5293 {
5295 /* Get the Jth argument in the parameter pack. */
5299 {
5300 /* Pack expansions must come at the end of the
5301 argument list. */
5304 {
5308 else
5311 }
5312 }
5315 /* We only care about the pattern. */
5321 /* This next two lines are the `argument expression is not just a
5322 simple identifier' condition and also the `specialized
5323 non-type argument' bit. */
5328 {
5329 /* Look at the corresponding template parameter,
5330 marking which template parameters its type depends
5331 upon. */
5335 {
5336 /* We haven't yet initialized TPD2. Do so now. */
5338 /* The number of parameters here is the number in the
5339 main template, which, as checked in the assertion
5340 above, is NARGS. */
5344 }
5346 /* Mark the template parameters. But this time, we're
5347 looking for the template parameters of the main
5348 template, not in the specialization. */
5355 NULL,
5359 {
5360 /* The type depended on some template parameters.
5361 If they are fully specialized in the
5362 specialization, that's OK. */
5371 "type %qT of template argument %qE depends "
5373 "type %qT of template argument %qE depends "
5375 type,
5376 arg);
5377 }
5378 }
5379 }
5380 }
5382 /* We should only get here once. */
5386 // Build the template decl.
5393 /* Give template template parms a DECL_CONTEXT of the template
5394 for which they are a parameter. */
5396 {
5400 }
5403 /* We didn't register this in check_explicit_specialization so we could
5404 wait until the constraints were set. */
5406 else
5413 /* Link the DECL_TEMPLATE_RESULT back to the partial TEMPLATE_DECL. */
5419 {
5425 {
5434 "declaration of %qD ambiguates earlier template "
5438 "partial specialization of %qD after instantiation "
5440 }
5441 }
5444 }
5446 /* PARM is a template parameter of some form; return the corresponding
5447 TEMPLATE_PARM_INDEX. */
5449 static tree
5451 {
5464 }
5466 /* Subroutine of fixed_parameter_pack_p below. Look for any template
5467 parameter packs used by the template parameter PARM. */
5469 static void
5471 {
5472 /* A type parm can't refer to another parm. */
5476 {
5480 }
5486 {
5490 else
5492 }
5493 }
5495 /* PARM is a template parameter pack. Return any parameter packs used in
5496 its type or the type of any of its template parameters. If there are
5497 any such packs, it will be instantiated into a fixed template parameter
5498 list by partial instantiation rather than be fully deduced. */
5500 tree
5502 {
5503 /* This can only be true in a member template. */
5506 /* This can only be true for a parameter pack. */
5509 /* A type parm can't refer to another parm. */
5523 }
5525 /* Check that a template declaration's use of default arguments and
5526 parameter packs is not invalid. Here, PARMS are the template
5527 parameters. IS_PRIMARY is true if DECL is the thing declared by
5528 a primary template. IS_PARTIAL is true if DECL is a partial
5529 specialization.
5531 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
5532 function template declaration or a friend class template
5533 declaration. In the function case, 1 indicates a declaration, 2
5534 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
5535 emitted for extraneous default arguments.
5537 Returns TRUE if there were no errors found, FALSE otherwise. */
5539 bool
5542 {
5545 tree parm_level;
5548 /* [temp.param]
5550 A default template-argument shall not be specified in a
5551 function template declaration or a function template definition, nor
5552 in the template-parameter-list of the definition of a member of a
5553 class template. */
5557 /* You can't have a function template declaration in a local
5558 scope, nor you can you define a member of a class template in a
5559 local scope. */
5567 /* A lambda doesn't have an explicit declaration; don't complain
5568 about the parms of the enclosing class. */
5575 /* If this is either a friend defined in the scope of the class
5576 or a member function. */
5582 /* And, if it was a member function, it really was defined in
5583 the scope of the class. */
5586 /* We already checked these parameters when the template was
5587 declared, so there's no need to do it again now. This function
5588 was defined in class scope, but we're processing its body now
5589 that the class is complete. */
5592 /* Core issue 226 (C++0x only): the following only applies to class
5593 templates. */
5596 {
5597 /* [temp.param]
5599 If a template-parameter has a default template-argument, all
5600 subsequent template-parameters shall have a default
5601 template-argument supplied. */
5603 {
5610 {
5620 {
5622 /* For better subsequent error-recovery, we indicate that
5623 there should have been a default argument. */
5626 }
5628 && !is_friend_decl
5629 /* Don't complain about an enclosing partial
5630 specialization. */
5635 /* A fixed parameter pack will be partially
5636 instantiated into a fixed length list. */
5638 {
5639 /* A primary class template, primary variable template
5640 (DR 2032), or alias template can only have one
5641 parameter pack, at the end of the template
5642 parameter list. */
5650 }
5651 }
5652 }
5653 }
5656 || is_partial
5657 || !is_primary
5659 /* For an ordinary class template, default template arguments are
5660 allowed at the innermost level, e.g.:
5661 template <class T = int>
5662 struct S {};
5663 but, in a partial specialization, they're not allowed even
5664 there, as we have in [temp.class.spec]:
5666 The template parameter list of a specialization shall not
5667 contain default template argument values.
5669 So, for a partial specialization, or for a function template
5670 (in C++98/C++03), we look at all of them. */
5671 ;
5672 else
5673 /* But, for a primary class template that is not a partial
5674 specialization we look at all template parameters except the
5675 innermost ones. */
5678 /* Figure out what error message to issue. */
5693 else
5694 /* Per [temp.param]/9, "A default template-argument shall not be
5695 specified in the template-parameter-lists of the definition of
5696 a member of a class template that appears outside of the member's
5697 class.", thus if we aren't handling a member of a class template
5698 there is no need to examine the parameters. */
5702 /* If we're inside a class definition, there's no need to
5703 examine the parameters to the class itself. On the one
5704 hand, they will be checked when the class is defined, and,
5705 on the other, default arguments are valid in things like:
5706 template <class T = double>
5707 struct S { template <class U> void f(U); };
5708 Here the default argument for `S' has no bearing on the
5709 declaration of `f'. */
5711 else
5712 /* Check everything. */
5718 {
5725 {
5730 {
5732 {
5739 }
5741 /* Clear out the default argument so that we are not
5742 confused later. */
5744 }
5745 }
5747 /* At this point, if we're still interested in issuing messages,
5748 they must apply to classes surrounding the object declared. */
5752 }
5755 }
5757 /* Worker for push_template_decl_real, called via
5758 for_each_template_parm. DATA is really an int, indicating the
5759 level of the parameters we are interested in. If T is a template
5760 parameter of that level, return nonzero. */
5762 static int
5764 {
5770 else
5773 }
5775 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5776 DATA is really an int, indicating the innermost outer level of parameters.
5777 If T is a template parameter of that level or further out, return
5778 nonzero. */
5780 static int
5782 {
5788 else
5791 }
5793 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5794 parameters given by current_template_args, or reuses a
5795 previously existing one, if appropriate. Returns the DECL, or an
5796 equivalent one, if it is replaced via a call to duplicate_decls.
5798 If IS_FRIEND is true, DECL is a friend declaration. */
5800 tree
5802 {
5806 /* See if this is a partial specialization. */
5815 /* No surprising friend functions. */
5820 tree ctx;
5822 /* For a friend, we want the context of the friend, not
5823 the type of which it is a friend. */
5827 /* In the case of a virtual function, we want the class in which
5828 it is defined. */
5830 else
5831 /* Otherwise, if we're currently defining some class, the DECL
5832 is assumed to be a member of the class. */
5841 /* See if this is a primary template. */
5845 /* A friend template that specifies a class context, i.e.
5846 template <typename T> friend void A<T>::f();
5847 is not primary. */
5848 ;
5850 /* Lambdas are not primary. */
5851 ;
5852 else
5855 /* True if the template is a member template, in the sense of
5856 [temp.mem]. */
5860 {
5868 {
5871 }
5873 {
5875 {
5878 }
5880 {
5881 /* [temp.mem]
5883 A destructor shall not be a member template. */
5887 }
5894 {
5895 /* [basic.stc.dynamic.allocation]
5897 An allocation function can be a function
5898 template. ... Template allocation functions shall
5899 have two or more parameters. */
5902 }
5903 }
5909 /* alias-declaration */
5915 else
5916 {
5919 }
5920 }
5927 /* Check to see that the rules regarding the use of default
5928 arguments are not being violated. We check args for a friend
5929 functions when we know whether it's a definition, introducing
5930 declaration or re-declaration. */
5935 /* Ensure that there are no parameter packs in the type of this
5936 declaration that have not been expanded. */
5938 {
5939 /* Check each of the arguments individually to see if there are
5940 any bare parameter packs. */
5946 {
5949 {
5950 /* This is a PARM_DECL that contains unexpanded parameter
5951 packs. We have already complained about this in the
5952 check_for_bare_parameter_packs call, so just replace
5953 these types with ERROR_MARK_NODE. */
5956 }
5960 }
5962 /* Check for bare parameter packs in the return type and the
5963 exception specifiers. */
5965 /* Errors were already issued, set return type to int
5966 as the frontend doesn't expect error_mark_node as
5967 the return type. */
5971 }
5972 else
5973 {
5977 {
5980 }
5985 }
5994 {
5995 /* Does not get a template head. */
5998 }
6005 {
6010 /* If DECL is a TYPE_DECL for a class-template, then there won't
6011 be DECL_LANG_SPECIFIC. The information equivalent to
6012 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
6016 {
6017 /* Since a template declaration already existed for this
6018 class-type, we must be redeclaring it here. Make sure
6019 that the redeclaration is valid. */
6021 current_template_parms,
6023 /* We don't need to create a new TEMPLATE_DECL; just use the
6024 one we already had. */
6026 }
6027 else
6028 {
6030 member_template_p);
6035 {
6036 /* A specialization of a member template of a template
6037 class. */
6041 }
6042 }
6043 }
6044 else
6045 {
6051 {
6054 }
6062 {
6063 /* The declaration is a specialization of a member
6064 template, declared outside the class. Therefore, the
6065 innermost template arguments will be NULL, so we
6066 replace them with the arguments determined by the
6067 earlier call to check_explicit_specialization. */
6070 tree new_tmpl
6072 member_template_p);
6080 args,
6083 }
6085 /* Make sure the template headers we got make sense. */
6090 {
6095 }
6096 else
6098 {
6103 {
6107 else
6111 /* Avoid crash in import_export_decl. */
6114 }
6119 /* Can happen in erroneous input. */
6121 else
6123 }
6125 /* Check that the parms are used in the appropriate qualifying scopes
6126 in the declarator. */
6130 {
6136 /* Avoid crash in import_export_decl. */
6139 }
6141 /* Check that the constraints for each enclosing template scope are
6142 consistent with the original declarations. */
6144 {
6148 {
6151 }
6153 {
6155 {
6159 }
6162 }
6163 }
6164 }
6169 {
6170 /* Push template declarations for global functions and types.
6171 Note that we do not try to push a global template friend
6172 declared in a template class; such a thing may well depend on
6173 the template parameters of the class and we'll push it when
6174 instantiating the befriending class. */
6177 {
6182 /* pushdecl may have found an existing template. */
6184 {
6187 }
6188 }
6190 {
6191 /* Record this decl as belonging to the current class. It's
6192 not chained onto anything else. */
6196 }
6197 }
6199 /* The type may have been completed, or (erroneously) changed. */
6203 {
6205 {
6210 /* Give template template parms a DECL_CONTEXT of the template
6211 for which they are a parameter. */
6214 {
6218 }
6222 {
6225 {
6226 /* ??? Why don't we do this here for all templates? */
6229 }
6232 }
6233 }
6235 /* The DECL_TI_ARGS of DECL contains full set of arguments
6236 referring wback to its most general template. If TMPL is a
6237 specialization, ARGS may only have the innermost set of
6238 arguments. Add the missing argument levels if necessary. */
6246 else
6247 {
6250 }
6251 }
6254 && !is_friend
6257 /* Set DECL_COMDAT on template instantiations; if we force
6258 them to be emitted by explicit instantiation,
6259 mark_needed will tell cgraph to do the right thing. */
6265 }
6267 /* FN is an inheriting constructor that inherits from the constructor
6268 template INHERITED; turn FN into a constructor template with a matching
6269 template header. */
6271 tree
6273 {
6274 tree inner_parms
6277 tree parms
6286 }
6288 /* Called when a class template TYPE is redeclared with the indicated
6289 template PARMS, e.g.:
6291 template <class T> struct S;
6292 template <class T> struct S {}; */
6294 bool
6296 {
6297 tree tmpl;
6298 tree tmpl_parms;
6302 {
6305 }
6309 /* The type is nested in some template class. Nothing to worry
6310 about here; there are no new template parameters for the nested
6311 type. */
6315 {
6317 tmpl);
6319 }
6325 {
6335 }
6338 {
6339 tree tmpl_parm;
6340 tree parm;
6352 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
6353 TEMPLATE_DECL. */
6363 {
6364 auto_diagnostic_group d;
6368 else
6371 }
6373 /* The parameters can be declared to introduce different
6374 constraints. */
6378 {
6379 auto_diagnostic_group d;
6385 }
6387 /* Give each template template parm in this redeclaration a
6388 DECL_CONTEXT of the template for which they are a parameter. */
6390 {
6394 }
6395 }
6404 /* Two classes with different constraints declare different entities. */
6406 {
6407 auto_diagnostic_group d;
6413 }
6416 }
6418 /* The actual substitution part of instantiate_non_dependent_expr,
6419 to be used when the caller has already checked
6420 !instantiation_dependent_uneval_expression_p (expr)
6421 and cleared processing_template_decl. */
6423 tree
6425 {
6428 complain,
6430 }
6432 /* Instantiate the non-dependent expression EXPR. */
6434 tree
6437 {
6442 {
6443 /* The caller should have checked this already. */
6445 processing_template_decl_sentinel s;
6447 }
6449 }
6451 /* Like instantiate_non_dependent_expr, but return NULL_TREE if the
6452 expression is dependent or non-constant. */
6454 tree
6456 {
6460 {
6463 else
6464 {
6465 processing_template_decl_sentinel s;
6467 }
6468 }
6470 }
6472 /* True iff T is a specialization of a variable template. */
6474 bool
6476 {
6481 }
6483 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
6484 template declaration, or a TYPE_DECL for an alias declaration. */
6486 bool
6488 {
6496 }
6498 /* If T is a specialization of an alias template, return it; otherwise return
6499 NULL_TREE. If TRANSPARENT_TYPEDEFS is true, look through other aliases. */
6501 tree
6504 {
6508 /* It's an alias template specialization if it's an alias and its
6509 TYPE_NAME is a specialization of a primary template. */
6511 {
6518 transparent_typedefs);
6519 }
6522 }
6524 /* Data structure for complex_alias_template_*. */
6526 struct uses_all_template_parms_data
6527 {
6530 };
6532 /* walk_tree callback for complex_alias_template_p. */
6534 static tree
6536 {
6541 {
6546 {
6550 }
6553 }
6558 /* An alias template with a pack expansion that expands a pack from the
6559 enclosing class needs to be considered complex, to avoid confusion with
6560 the same pack being used as an argument to the alias's own template
6561 parameter (91966). */
6564 {
6573 /* Consider the expanded packs to be used outside the expansion... */
6575 }
6577 /* ...but don't walk into the pattern. Consider PR104008:
6579 template <typename T, typename... Ts>
6580 using IsOneOf = disjunction<is_same<T, Ts>...>;
6582 where IsOneOf seemingly uses all of its template parameters in its
6583 expansion (and does not expand a pack from the enclosing class), so the
6584 alias was not marked as complex. However, if it is used like
6585 "IsOneOf<T>", the empty pack for Ts means that T no longer appears in the
6586 expansion. So only Ts is considered used by the pack expansion. */
6590 }
6592 /* An alias template is complex from a SFINAE perspective if a template-id
6593 using that alias can be ill-formed when the expansion is not, as with
6594 the void_t template.
6596 Returns 1 if always complex, 0 if not complex, -1 if complex iff any of the
6597 template arguments are empty packs. */
6599 static bool
6601 {
6602 /* A renaming alias isn't complex. */
6606 /* Any other constrained alias is complex. */
6625 }
6627 /* If T is a specialization of a complex alias template with dependent
6628 template-arguments, return it; otherwise return NULL_TREE. If T is a
6629 typedef to such a specialization, return the specialization. */
6631 tree
6633 {
6644 && (any_dependent_template_arguments_p
6649 {
6652 }
6655 }
6657 /* Return the number of innermost template parameters in TMPL. */
6659 static int
6661 {
6664 }
6666 /* Return either TMPL or another template that it is equivalent to under DR
6667 1286: An alias that just changes the name of a template is equivalent to
6668 the other template. */
6670 static tree
6672 {
6675 {
6676 /* Determine if the alias is equivalent to an underlying template. */
6678 /* The underlying type may have been ill-formed. Don't proceed. */
6691 /* Does the alias add cv-quals? */
6699 /* Are any default template arguments equivalent? */
6704 {
6709 }
6711 /* If TMPL adds or changes any constraints, it isn't equivalent. I think
6712 it's appropriate to treat a less-constrained alias as equivalent. */
6716 /* Alias is equivalent. Strip it and repeat. */
6718 }
6719 top_break:;
6722 }
6724 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6725 must be a reference-to-function or a pointer-to-function type, as specified
6726 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6727 and check that the resulting function has external linkage. */
6729 static tree
6731 tsubst_flags_t complain)
6732 {
6735 linkage_kind linkage;
6753 /* [temp.arg.nontype]/1
6755 A template-argument for a non-type, non-template template-parameter
6756 shall be one of:
6757 [...]
6758 -- the address of an object or function with external [C++11: or
6759 internal] linkage. */
6763 {
6765 {
6772 else
6775 }
6777 }
6782 {
6784 {
6790 else
6794 }
6796 }
6798 accept:
6800 {
6803 else
6805 }
6810 }
6812 /* Subroutine of convert_nontype_argument.
6813 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6814 Emit an error otherwise. */
6816 static bool
6818 tsubst_flags_t complain)
6819 {
6835 {
6841 else
6843 }
6845 }
6847 /* Returns TRUE iff the address of OP is value-dependent.
6849 14.6.2.4 [temp.dep.temp]:
6850 A non-integral non-type template-argument is dependent if its type is
6851 dependent or it has either of the following forms
6852 qualified-id
6853 & qualified-id
6854 and contains a nested-name-specifier which specifies a class-name that
6855 names a dependent type.
6857 We generalize this to just say that the address of a member of a
6858 dependent class is value-dependent; the above doesn't cover the
6859 address of a static data member named with an unqualified-id. */
6861 static bool
6863 {
6866 /* We could use get_inner_reference here, but there's no need;
6867 this is only relevant for template non-type arguments, which
6868 can only be expressed as &id-expression. */
6870 {
6881 }
6884 }
6886 /* The next set of functions are used for providing helpful explanatory
6887 diagnostics for failed overload resolution. Their messages should be
6888 indented by two spaces for consistency with the messages in
6889 call.cc */
6891 static int
6893 {
6895 }
6897 /* Other failure functions should call this one, to provide a single function
6898 for setting a breakpoint on. */
6900 static int
6902 {
6904 }
6906 static int
6908 {
6913 }
6915 static int
6917 {
6923 }
6925 static int
6927 {
6931 }
6933 static int
6935 {
6938 " template parameter %qD is not a parameter pack, but "
6942 }
6944 static int
6946 {
6949 " template argument %qE does not match "
6953 }
6955 static int
6957 {
6961 }
6963 static int
6965 {
6971 }
6973 static int
6975 {
6977 {
6982 else
6984 " deduced conflicting values for non-type parameter "
6986 }
6988 }
6990 static int
6992 {
6995 " variable-sized array type %qT is not "
6997 arg);
6999 }
7001 static int
7003 {
7007 arg);
7009 }
7011 static int
7013 {
7015 {
7021 else
7026 }
7028 }
7030 static int
7032 {
7034 }
7036 static int
7039 {
7041 }
7043 static int
7046 {
7052 }
7054 static int
7057 {
7060 {
7068 }
7070 }
7072 static int
7074 {
7077 " template parameters of a template template argument are "
7080 }
7082 static int
7084 {
7090 }
7092 static int
7094 {
7099 }
7101 /* Subroutine of convert_nontype_argument, to check whether EXPR, as an
7102 argument for TYPE, points to an unsuitable object.
7104 Also adjust the type of the index in C++20 array subobject references. */
7106 static bool
7108 {
7110 {
7111 CASE_CONVERT:
7113 complain);
7117 complain);
7120 {
7124 }
7128 {
7134 {
7138 /* Canonicalize array offsets to ptrdiff_t; how they were
7139 written doesn't matter for subobject identity. */
7142 }
7145 {
7148 "%qE is not a valid template argument of type %qT "
7152 }
7154 {
7157 "%qE is not a valid template argument of type %qT "
7161 }
7164 {
7167 "%qE is not a valid template argument of type %qT "
7170 }
7171 /* C++17: For a non-type template-parameter of reference or pointer
7172 type, the value of the constant expression shall not refer to (or
7173 for a pointer type, shall not be the address of):
7174 * a subobject (4.5),
7175 * a temporary object (15.2),
7176 * a string literal (5.13.5),
7177 * the result of a typeid expression (8.2.8), or
7178 * a predefined __func__ variable (11.4.1). */
7180 {
7183 decl);
7185 }
7187 && !(same_type_ignoring_top_level_qualifiers_p
7190 {
7195 }
7197 {
7201 decl);
7203 }
7204 }
7212 else
7213 {
7215 {
7218 "because %qD is a variable, not the address of "
7221 }
7222 else
7223 {
7229 }
7230 }
7231 }
7234 }
7236 /* Return a VAR_DECL for the C++20 template parameter object corresponding to
7237 template argument EXPR. */
7239 static tree
7241 {
7246 {
7251 }
7255 /* This is no longer a compound literal. */
7259 }
7261 /* The template arguments corresponding to template parameter objects of types
7262 that contain pointers to members. */
7266 /* Find or build an nttp object for (already-validated) EXPR with name
7267 NAME. */
7269 tree
7271 {
7288 {
7289 /* If EXPR contains any PTRMEM_CST, they will get clobbered by
7290 lower_var_init before we're done mangling. So store the original
7291 value elsewhere. */
7294 }
7299 }
7301 /* Return the actual template argument corresponding to template parameter
7302 object VAR. */
7304 tree
7306 {
7310 }
7312 /* Attempt to convert the non-type template parameter EXPR to the
7313 indicated TYPE. If the conversion is successful, return the
7314 converted value. If the conversion is unsuccessful, return
7315 NULL_TREE if we issued an error message, or error_mark_node if we
7316 did not. We issue error messages for out-and-out bad template
7317 parameters, but not simply because the conversion failed, since we
7318 might be just trying to do argument deduction. Both TYPE and EXPR
7319 must be non-dependent.
7321 The conversion follows the special rules described in
7322 [temp.arg.nontype], and it is much more strict than an implicit
7323 conversion.
7325 This function is called twice for each template argument (see
7326 lookup_template_class for a more accurate description of this
7327 problem). This means that we need to handle expressions which
7328 are not valid in a C++ source, but can be created from the
7329 first call (for instance, casts to perform conversions). These
7330 hacks can go away after we fix the double coercion problem. */
7332 static tree
7334 {
7335 tree expr_type;
7338 /* Detect immediately string literals as invalid non-type argument.
7339 This special-case is not needed for correctness (we would easily
7340 catch this later), but only to provide better diagnostic for this
7341 common user mistake. As suggested by DR 100, we do not mention
7342 linkage issues in the diagnostic as this is not the point. */
7344 {
7350 }
7352 /* Add the ADDR_EXPR now for the benefit of
7353 value_dependent_expression_p. */
7356 {
7360 }
7362 /* If we are in a template, EXPR may be non-dependent, but still
7363 have a syntactic, rather than semantic, form. For example, EXPR
7364 might be a SCOPE_REF, rather than the VAR_DECL to which the
7365 SCOPE_REF refers. Preserving the qualifying scope is necessary
7366 so that access checking can be performed when the template is
7367 instantiated -- but here we need the resolved form so that we can
7368 convert the argument. */
7380 /* If the argument is non-dependent, perform any conversions in
7381 non-dependent context as well. */
7389 else
7392 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
7393 to a non-type argument of "nullptr". */
7397 /* In C++11, integral or enumeration non-type template arguments can be
7398 arbitrary constant expressions. Pointer and pointer to
7399 member arguments can be general constant expressions that evaluate
7400 to a null value, but otherwise still need to be of a specific form. */
7402 {
7404 /* A PTRMEM_CST is already constant, and a valid template
7405 argument for a parameter of pointer to member type, we just want
7406 to leave it in that form rather than lower it to a
7410 {
7411 /* C++17: A template-argument for a non-type template-parameter shall
7412 be a converted constant expression (8.20) of the type of the
7413 template-parameter. */
7416 /* Make sure we return NULL_TREE only if we have really issued
7417 an error, as described above. */
7420 {
7423 }
7426 /* EXPR may have become value-dependent. */
7428 }
7430 {
7435 }
7436 }
7440 else
7443 /* HACK: Due to double coercion, we can get a
7444 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
7445 which is the tree that we built on the first call (see
7446 below when coercing to reference to object or to reference to
7447 function). We just strip everything and get to the arg.
7448 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
7449 for examples. */
7451 {
7452 /* Check this before we strip *& to avoid redundancy. */
7461 {
7462 /* ??? Maybe we could use convert_from_reference here, but we
7463 would need to relax its constraints because the NOP_EXPR
7464 could actually change the type to something more cv-qualified,
7465 and this is not folded by convert_from_reference. */
7470 && (same_type_ignoring_top_level_qualifiers_p
7473 {
7476 }
7477 }
7478 }
7480 /* [temp.arg.nontype]/5, bullet 1
7482 For a non-type template-parameter of integral or enumeration type,
7483 integral promotions (_conv.prom_) and integral conversions
7484 (_conv.integral_) are applied. */
7487 {
7489 {
7494 }
7499 /* Notice that there are constant expressions like '4 % 0' which
7500 do not fold into integer constants. */
7502 {
7504 {
7508 else
7514 /* else cxx_constant_value complained but gave us
7515 a real constant, so go ahead. */
7517 {
7518 /* Some assemble time constant expressions like
7519 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
7520 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
7521 as we can emit them into .rodata initializers of
7522 variables, yet they can't fold into an INTEGER_CST at
7523 compile time. Refuse them here. */
7528 }
7529 }
7530 else
7532 }
7534 /* Avoid typedef problems. */
7537 }
7538 /* [temp.arg.nontype]/5, bullet 2
7540 For a non-type template-parameter of type pointer to object,
7541 qualification conversions (_conv.qual_) and the array-to-pointer
7542 conversion (_conv.array_) are applied. */
7544 {
7547 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
7548 decay_conversion or an explicit cast. If it's a problematic cast,
7549 we'll complain about it below. */
7551 {
7556 {
7559 }
7560 }
7562 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
7564 A template-argument for a non-type, non-template template-parameter
7565 shall be one of: [...]
7567 -- the name of a non-type template-parameter;
7568 -- the address of an object or function with external linkage, [...]
7569 expressed as "& id-expression" where the & is optional if the name
7570 refers to a function or array, or if the corresponding
7571 template-parameter is a reference.
7573 Here, we do not care about functions, as they are invalid anyway
7574 for a parameter of type pointer-to-object. */
7577 /* Non-type template parameters are OK. */
7578 ;
7583 /* Other values, like integer constants, might be valid
7584 non-type arguments of some other type. */
7594 }
7595 /* [temp.arg.nontype]/5, bullet 3
7597 For a non-type template-parameter of type reference to object, no
7598 conversions apply. The type referred to by the reference may be more
7599 cv-qualified than the (otherwise identical) type of the
7600 template-argument. The template-parameter is bound directly to the
7601 template-argument, which must be an lvalue. */
7603 {
7605 expr_type))
7609 {
7614 }
7617 {
7622 }
7624 /* [temp.arg.nontype]/1
7626 A template-argument for a non-type, non-template template-parameter
7627 shall be one of: [...]
7629 -- the address of an object or function with external linkage. */
7632 {
7635 {
7638 "because a reference variable does not have a constant "
7641 }
7642 }
7645 /* OK, dependent reference. We don't want to ask whether a DECL is
7647 else
7648 {
7653 }
7657 }
7658 /* [temp.arg.nontype]/5, bullet 4
7660 For a non-type template-parameter of type pointer to function, only
7661 the function-to-pointer conversion (_conv.func_) is applied. If the
7662 template-argument represents a set of overloaded functions (or a
7663 pointer to such), the matching function is selected from the set
7664 (_over.over_). */
7666 {
7667 /* If the argument is a template-id, we might not have enough
7668 context information to decay the pointer. */
7670 {
7674 }
7677 /* Null pointer values are OK in C++11. */
7683 }
7684 /* [temp.arg.nontype]/5, bullet 5
7686 For a non-type template-parameter of type reference to function, no
7687 conversions apply. If the template-argument represents a set of
7688 overloaded functions, the matching function is selected from the set
7689 (_over.over_). */
7691 {
7693 {
7695 {
7700 }
7702 }
7707 }
7708 /* [temp.arg.nontype]/5, bullet 6
7710 For a non-type template-parameter of type pointer to member function,
7711 no conversions apply. If the template-argument represents a set of
7712 overloaded member functions, the matching member function is selected
7713 from the set (_over.over_). */
7715 {
7720 /* [temp.arg.nontype] bullet 1 says the pointer to member
7721 expression must be a pointer-to-member constant. */
7726 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
7727 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
7730 }
7731 /* [temp.arg.nontype]/5, bullet 7
7733 For a non-type template-parameter of type pointer to data member,
7734 qualification conversions (_conv.qual_) are applied. */
7736 {
7737 /* [temp.arg.nontype] bullet 1 says the pointer to member
7738 expression must be a pointer-to-member constant. */
7746 }
7748 {
7750 {
7755 }
7757 }
7759 {
7760 /* Replace the argument with a reference to the corresponding template
7761 parameter object. */
7766 }
7767 /* A template non-type parameter must be one of the above. */
7768 else
7771 /* Sanity check: did we actually convert the argument to the
7772 right type? */
7776 }
7778 /* Subroutine of coerce_template_template_parms, which returns 1 if
7779 PARM_PARM and ARG_PARM match using the rule for the template
7780 parameters of template template parameters. Both PARM and ARG are
7781 template parameters; the rest of the arguments are the same as for
7782 coerce_template_template_parms.
7783 */
7784 static int
7786 tree arg,
7787 tsubst_flags_t complain,
7788 tree in_decl,
7789 tree outer_args)
7790 {
7799 {
7801 /* We encounter instantiations of templates like
7802 template <template <template <class> class> class TT>
7803 class C; */
7804 {
7808 }
7809 /* Fall through. */
7814 /* Argument is a parameter pack but parameter is not. */
7819 /* The tsubst call is used to handle cases such as
7821 template <int> class C {};
7822 template <class T, template <T> class TT> class D {};
7823 D<int, C> d;
7825 i.e. the parameter list of TT depends on earlier parameters. */
7827 {
7832 }
7836 /* Argument is a parameter pack but parameter is not. */
7843 }
7846 }
7848 /* Coerce template argument list ARGLIST for use with template
7849 template-parameter TEMPL. */
7851 static tree
7853 tsubst_flags_t complain)
7854 {
7855 /* Consider an example where a template template parameter declared as
7857 template <class T, class U = std::allocator<T> > class TT
7859 The template parameter level of T and U are one level larger than
7860 of TT. To proper process the default argument of U, say when an
7861 instantiation `TT<int>' is seen, we need to build the full
7862 arguments containing {int} as the innermost level. Outer levels,
7863 available when not appearing as default template argument, can be
7864 obtained from the arguments of the enclosing template.
7866 Suppose that TT is later substituted with std::vector. The above
7867 instantiation is `TT<int, std::allocator<T> >' with TT at
7868 level 1, and T at level 2, while the template arguments at level 1
7869 becomes {std::vector} and the inner level 2 is {int}. */
7875 {
7876 /* This is an argument of the current template, so we haven't set
7877 DECL_CONTEXT yet. We can also get here when level-lowering a
7878 bound ttp. */
7879 tree relevant_template_parms;
7881 /* Parameter levels that are greater than the level of the given
7882 template template parm are irrelevant. */
7889 }
7896 }
7898 /* A cache of template template parameters with match-all default
7899 arguments. */
7902 /* T is a bound template template-parameter. Copy its arguments into default
7903 arguments of the template template-parameter's template parameters. */
7905 static tree
7907 {
7930 {
7933 {
7936 }
7937 }
7941 }
7943 /* ARG is a bound potential template template-argument, and PARGS is a list
7944 of arguments for the corresponding template template-parameter. Adjust
7945 PARGS as appropriate for application to ARG's template, and if ARG is a
7946 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7947 arguments to the template template parameter. */
7949 static tree
7951 {
7955 {
7956 /* When comparing two template template-parameters in partial ordering,
7957 rewrite the one currently being used as an argument to have default
7958 arguments for all parameters. */
7964 }
7965 else
7966 {
7967 tree aparms
7970 }
7973 }
7975 /* Subroutine of unify for the case when PARM is a
7976 BOUND_TEMPLATE_TEMPLATE_PARM. */
7978 static int
7981 {
7985 /* The template template parm might be variadic and the argument
7986 not, so flatten both argument lists. */
7991 {
7992 /* In keeping with P0522R0, adjust P's template arguments
7993 to apply to A's template; then flatten it again. */
8001 /* If the P0522 adjustment eliminated a pack expansion, deduce
8002 empty packs. */
8008 }
8009 else
8010 {
8011 /* Deduce arguments T, i from TT<T> or TT<i>.
8012 We check each element of PARMVEC and ARGVEC individually
8013 rather than the whole TREE_VEC since they can have
8014 different number of elements, which is allowed under N2555. */
8018 /* Check if the parameters end in a pack, making them
8019 variadic. */
8026 /* If the template argument list of P contains a pack
8027 expansion that is not the last template argument, the
8028 entire template argument list is a non-deduced
8029 context. */
8047 DEDUCE_EXACT,
8050 }
8053 }
8055 /* Return 1 if PARM_TMPL and ARG_TMPL match using rule for
8056 template template parameters.
8058 Consider the example:
8059 template <class T> class A;
8060 template<template <class U> class TT> class B;
8062 For B<A>, PARM_TMPL is TT, while ARG_TMPL is A,
8063 and OUTER_ARGS contains A. */
8065 static int
8067 tree arg_tmpl,
8068 tsubst_flags_t complain,
8069 tree in_decl,
8070 tree outer_args)
8071 {
8087 {
8088 /* P0522R0: A template template-parameter P is at least as specialized as
8089 a template template-argument A if, given the following rewrite to two
8090 function templates, the function template corresponding to P is at
8091 least as specialized as the function template corresponding to A
8092 according to the partial ordering rules for function templates
8093 ([temp.func.order]). Given an invented class template X with the
8094 template parameter list of A (including default arguments):
8096 * Each of the two function templates has the same template parameters,
8097 respectively, as P or A.
8099 * Each function template has a single function parameter whose type is
8100 a specialization of X with template arguments corresponding to the
8101 template parameters from the respective function template where, for
8102 each template parameter PP in the template parameter list of the
8103 function template, a corresponding template argument AA is formed. If
8104 PP declares a parameter pack, then AA is the pack expansion
8105 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
8107 If the rewrite produces an invalid type, then P is not at least as
8108 specialized as A. */
8110 /* So coerce P's args to apply to A's parms, and then deduce between A's
8111 args and the converted args. If that succeeds, A is at least as
8112 specialized as P, so they match.*/
8118 /* PARM and ARG might be at different template depths, and we want to
8119 pass the right additional levels of args when coercing PARGS to
8120 ARG_PARMS in case we need to do any substitution into non-type
8121 template parameter types.
8123 OUTER_ARGS are not the right outer levels in this case, as they are
8124 the args we're building up for PARM, and for the coercion we want the
8125 args for ARG. If DECL_CONTEXT isn't set for a template template
8126 parameter, we can assume that it's in the current scope. In that case
8127 we might end up adding more levels than needed, but that shouldn't be
8128 a problem; any args we need to refer to are at the right level. */
8139 {
8145 }
8146 }
8148 /* Determine whether we have a parameter pack at the end of the
8149 template template parameter's template parameter list. */
8151 {
8158 {
8172 }
8173 }
8179 /* Check all of the template parameters except the parameter pack at
8180 the end (if any). */
8182 {
8191 outer_args))
8194 }
8197 {
8198 /* Check each of the template parameters in the template
8199 argument against the template parameter pack at the end of
8200 the template template parameter. */
8207 {
8214 outer_args))
8216 }
8217 }
8220 }
8222 /* Verifies that the deduced template arguments (in TARGS) for the
8223 template template parameters (in TPARMS) represent valid bindings,
8224 by comparing the template parameter list of each template argument
8225 to the template parameter list of its corresponding template
8226 template parameter, in accordance with DR150. This
8227 routine can only be called after all template arguments have been
8228 deduced. It will return TRUE if all of the template template
8229 parameter bindings are okay, FALSE otherwise. */
8230 bool
8232 {
8236 /* We're dealing with template parms in this process. */
8242 {
8247 {
8252 {
8253 /* Look inside the argument pack. */
8256 }
8259 {
8261 /* Extract the next argument from the argument
8262 pack. */
8266 /* Look at the pattern of the pack expansion. */
8269 /* Extract the template parameters from the template
8270 argument. */
8274 /* Verify that we can coerce the template template
8275 parameters from the template argument to the template
8276 parameter. This requires an exact match. */
8278 && !coerce_template_template_parms
8280 targ,
8281 tf_none,
8282 tparm,
8283 targs))
8284 {
8287 }
8288 }
8289 }
8290 }
8292 out:
8296 }
8298 /* Since type attributes aren't mangled, we need to strip them from
8299 template type arguments. */
8301 tree
8303 {
8313 }
8315 /* And from inside dependent non-type arguments like sizeof(Type). */
8317 static tree
8319 {
8329 }
8331 /* A template declaration can be substituted for a constrained
8332 template template parameter only when the argument is no more
8333 constrained than the parameter. */
8335 static bool
8337 {
8340 /* For now, allow constrained template template arguments
8341 and unconstrained template template parameters. */
8345 /* If the template parameter is constrained, we need to rewrite its
8346 constraints in terms of the ARG's template parameters. This ensures
8347 that all of the template parameter types will have the same depth.
8349 Note that this is only valid when coerce_template_template_parm is
8350 true for the innermost template parameters of PARM and ARG. In other
8351 words, because coercion is successful, this conversion will be valid. */
8354 {
8363 }
8366 }
8368 // Convert a placeholder argument into a binding to the original
8369 // parameter. The original parameter is saved as the TREE_TYPE of
8370 // ARG.
8373 {
8376 }
8378 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
8379 because one of them is dependent. But we need to represent the
8380 conversion for the benefit of cp_tree_equal. */
8382 static tree
8384 {
8385 /* Auto parms get no conversion. */
8388 /* We don't need or want to add this conversion now if we're going to use the
8389 argument for deduction. */
8401 }
8403 /* Convert the indicated template ARG as necessary to match the
8404 indicated template PARM. Returns the converted ARG, or
8405 error_mark_node if the conversion was unsuccessful. Error and
8406 warning messages are issued under control of COMPLAIN. This
8407 conversion is for the Ith parameter in the parameter list. ARGS is
8408 the full set of template arguments deduced so far. */
8410 static tree
8412 tree arg,
8413 tree args,
8414 tsubst_flags_t complain,
8416 tree in_decl)
8417 {
8418 tree orig_arg;
8419 tree val;
8425 /* Trivially convert placeholders. */
8434 {
8435 /* The template argument was the name of some
8436 member function. That's usually
8437 invalid, but static members are OK. In any
8438 case, grab the underlying fields/functions
8439 and issue an error later if required. */
8441 }
8449 /* When determining whether an argument pack expansion is a template,
8450 look at the pattern. */
8454 /* Deal with an injected-class-name used as a template template arg. */
8456 {
8459 {
8469 }
8470 }
8472 is_tmpl_type =
8488 {
8490 {
8494 }
8497 "to refer to a type member of a template parameter, "
8502 typename_type,
8503 complain);
8506 }
8508 {
8510 {
8512 {
8517 {
8518 /* The template argument is a type, but we're expecting
8519 an expression. */
8524 /* [temp.arg]/2: "In a template-argument, an ambiguity
8525 between a type-id and an expression is resolved to a
8526 type-id, regardless of the form of the corresponding
8527 template-parameter." So give the user a clue. */
8530 "for non-type template parameter is treated as "
8532 }
8536 else
8539 }
8540 }
8542 }
8544 {
8546 {
8553 else
8556 }
8558 }
8561 /* We already did the appropriate conversion when packing args. */
8564 {
8566 {
8568 /* The number of argument required is not known yet.
8569 Just accept it for now. */
8571 else
8572 {
8573 /* Strip alias templates that are equivalent to another
8574 template. */
8579 args))
8580 {
8583 /* TEMPLATE_TEMPLATE_PARM node is preferred over
8584 TEMPLATE_DECL. */
8586 {
8591 }
8592 }
8593 else
8594 {
8596 {
8603 }
8606 }
8608 // Check that the constraints are compatible before allowing the
8609 // substitution.
8612 {
8614 {
8620 }
8622 }
8623 }
8624 }
8625 else
8627 /* We only form one instance of each template specialization.
8628 Therefore, if we use a non-canonical variant (i.e., a
8629 typedef), any future messages referring to the type will use
8630 the typedef, which is confusing if those future uses do not
8631 themselves also use the typedef. */
8634 }
8635 else
8636 {
8641 /* We don't have enough levels of args to do any substitution. This
8644 {
8649 }
8650 else
8653 /* Perform array-to-pointer and function-to-pointer conversion
8654 as per [temp.param]/10. */
8660 /* Drop top-level cv-qualifiers on the substituted/deduced type of
8661 this non-type template parameter, as per [temp.param]/6. */
8669 /* We used to call digest_init here. However, digest_init
8670 will report errors, which we don't want when complain
8671 is zero. More importantly, digest_init will try too
8672 hard to convert things: for example, `0' should not be
8673 converted to pointer type at this point according to
8674 the standard. Accepting this is not merely an
8675 extension, since deciding whether or not these
8676 conversions can occur is part of determining which
8677 function template to call, or whether a given explicit
8678 argument specification is valid. */
8680 else
8681 {
8684 }
8695 {
8696 /* Reject template arguments that are references to built-in
8697 functions with no library fallbacks. */
8706 }
8709 {
8710 /* Strip typedefs from the SCOPE_REF. */
8713 complain);
8716 }
8717 }
8720 }
8722 /* Coerces the remaining template arguments in INNER_ARGS (from
8723 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
8724 Returns the coerced argument pack. PARM_IDX is the position of this
8725 parameter in the template parameter list. ARGS is the original
8726 template argument list. */
8727 static tree
8730 tree args,
8731 tree inner_args,
8733 tree new_args,
8735 tree in_decl,
8736 tsubst_flags_t complain)
8737 {
8740 tree packed_args;
8741 tree argument_pack;
8748 {
8749 /* When the template parameter is a non-type template parameter pack
8750 or template template parameter pack whose type or template
8751 parameters use parameter packs, we know exactly how many arguments
8752 we are looking for. Build a vector of the instantiated decls for
8753 these template parameters in PACKED_PARMS. */
8754 /* We can't use make_pack_expansion here because it would interpret a
8755 _DECL as a use rather than a declaration. */
8769 /* If we're doing a partial instantiation of a member template,
8770 verify that all of the types used for the non-type
8771 template parameter pack are, in fact, valid for non-type
8772 template parameters. */
8775 {
8778 {
8783 }
8784 /* We don't know how many args we have yet, just
8785 use the unconverted ones for now. */
8787 }
8790 }
8791 /* Check if we have a placeholder pack, which indicates we're
8792 in the context of a introduction list. In that case we want
8793 to match this pack to the single placeholder. */
8797 {
8800 }
8801 else
8804 /* Convert the remaining arguments, which will be a part of the
8805 parameter pack "parm". */
8808 {
8814 {
8815 /* Once we've packed as many args as we have types, stop. */
8819 /* We don't know how many args we have yet, just
8820 use the unconverted ones for now. */
8822 else
8824 }
8827 {
8830 }
8831 else
8834 in_decl);
8838 }
8842 {
8847 }
8852 else
8853 {
8856 }
8863 }
8865 /* Returns the number of pack expansions in the template argument vector
8866 ARGS. */
8868 static int
8870 {
8875 {
8879 }
8881 }
8883 /* Convert all template arguments to their appropriate types, and
8884 return a vector containing the innermost resulting template
8885 arguments. If any error occurs, return error_mark_node. Error and
8886 warning messages are issued under control of COMPLAIN.
8888 If PARMS represents all template parameters levels, this function
8889 returns a vector of vectors representing all the resulting argument
8890 levels. Note that in this case, only the innermost arguments are
8891 coerced because the outermost ones are supposed to have been coerced
8892 already. Otherwise, if PARMS represents only (the innermost) vector
8893 of parameters, this function returns a vector containing just the
8894 innermost resulting arguments.
8896 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8897 for arguments not specified in ARGS. If REQUIRE_ALL_ARGS is true,
8898 arguments not specified in ARGS must have default arguments which
8899 we'll use to fill in ARGS. */
8901 tree
8903 tree args,
8904 tree in_decl,
8905 tsubst_flags_t complain,
8907 {
8909 tree orig_inner_args;
8910 tree inner_args;
8912 /* When used as a boolean value, indicates whether this is a
8913 variadic template parameter list. Since it's an int, we can also
8914 subtract it from nparms to get the number of non-variadic
8915 parameters. */
8920 /* Adjustment to nparms for fixed parameter packs. */
8925 /* Likewise for parameters with default arguments. */
8933 {
8935 {
8938 }
8940 }
8944 /* Determine if there are any parameter packs or default arguments. */
8946 {
8954 }
8957 /* If there are no parameters that follow a parameter pack, we need to
8958 expand any argument packs so that we can deduce a parameter pack from
8959 some non-packed args followed by an argument pack, as in variadic85.C.
8960 If there are such parameters, we need to leave argument packs intact
8961 so the arguments are assigned properly. This can happen when dealing
8962 with a nested class inside a partial specialization of a class
8963 template, as in variadic92.C, or when deducing a template parameter pack
8964 from a sub-declarator, as in variadic114.C. */
8968 /* Count any pack expansion args. */
8974 && require_all_args
8975 && !variadic_args_p
8978 {
8979 bad_nargs:
8981 {
8983 {
8987 }
8988 else
8995 }
8998 }
8999 /* We can't pass a pack expansion to a non-pack parameter of an alias
9000 template (DR 1430). */
9004 && variadic_args_p
9006 {
9008 {
9010 {
9016 {
9019 "pack expansion argument for non-pack parameter "
9021 else
9023 "pack expansion argument for non-pack parameter "
9027 }
9028 }
9030 found:;
9031 }
9033 }
9035 /* We need to evaluate the template arguments, even though this
9036 template-id may be nested within a "sizeof". */
9037 cp_evaluated ev;
9043 {
9044 tree arg;
9045 tree parm;
9047 /* Get the Ith template parameter. */
9051 {
9054 }
9056 /* Calculate the next argument. */
9059 else
9065 {
9066 /* Some arguments will be placed in the
9067 template parameter pack PARM. */
9074 {
9075 /* We don't know how many args we have yet, just use the
9076 unconverted (and still packed) ones for now. */
9080 }
9084 /* Store this argument. */
9086 {
9087 lost++;
9088 /* We are done with all of the arguments. */
9091 }
9092 else
9093 {
9097 {
9100 }
9101 }
9104 }
9106 {
9108 {
9109 /* "If every valid specialization of a variadic template
9110 requires an empty template parameter pack, the template is
9111 ill-formed, no diagnostic required." So check that the
9112 pattern works with this parameter. */
9117 in_decl);
9119 {
9124 }
9126 /* Recover from missing typename. */
9130 /* We don't know how many args we have yet, just
9131 use the unconverted ones for now. */
9135 }
9136 }
9138 {
9139 /* There must be a default arg in this case. */
9142 /* The position of the first default template argument,
9143 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
9144 Record that. */
9148 }
9149 else
9153 {
9156 }
9158 {
9159 /* This can occur if there was an error in the template
9160 parameter list itself (which we would already have
9161 reported) that we are trying to recover from, e.g., a class
9162 template with a parameter list such as
9163 template<typename..., typename> (cpp0x/variadic150.C). */
9166 /* This can also happen with a fixed parameter pack (71834). */
9169 }
9170 else
9176 lost++;
9179 }
9182 {
9183 /* If we had fixed parameter packs, we didn't know how many arguments we
9184 actually needed earlier; now we do. */
9188 }
9191 {
9192 /* We had some pack expansion arguments that will only work if the packs
9193 are empty, but wait until instantiation time to complain.
9194 See variadic-ttp3.C. */
9196 /* Except that we can't provide empty packs to alias templates or
9197 concepts when there are no corresponding parameters. Basically,
9198 we can get here with this:
9200 template<typename T> concept C = true;
9202 template<typename... Args>
9203 requires C<Args...>
9204 void f();
9206 When parsing C<Args...>, we try to form a concept check of
9207 C<?, Args...>. Without the extra check for substituting an empty
9208 pack past the last parameter, we can accept the check as valid.
9210 FIXME: This may be valid for alias templates (but I doubt it).
9212 FIXME: The error could be better also. */
9214 {
9219 }
9230 }
9233 {
9236 }
9243 }
9245 /* Returns true if T is a wrapper to make a C++20 template parameter
9246 object const. */
9248 static bool
9250 {
9256 }
9258 /* Returns 1 if template args OT and NT are equivalent. */
9260 int
9262 {
9275 /* DR 1558: Don't treat an alias template specialization with dependent
9276 arguments as equivalent to its underlying type when used as a template
9277 argument; we need them to be distinct so that we substitute into the
9278 specialization arguments at instantiation time. And aliases can't be
9279 equivalent without being ==, so we don't need to look any deeper.
9281 During partial ordering, however, we need to treat them normally so we can
9282 order uses of the same alias with different cv-qualification (79960). */
9288 /* For member templates */
9301 {
9305 }
9306 else
9307 {
9308 /* Try to treat a template non-type argument that has been converted
9309 to the parameter type as equivalent to one that hasn't yet. */
9323 }
9324 }
9326 /* Returns true iff the OLDARGS and NEWARGS are in fact identical sets of
9327 template arguments. Returns false otherwise, and updates OLDARG_PTR and
9328 NEWARG_PTR with the offending arguments if they are non-NULL. */
9330 bool
9334 {
9345 {
9350 {
9356 }
9357 }
9359 }
9363 {
9365 }
9367 /* Implement a freelist interface for objects of type T.
9369 Head is a separate object, rather than a regular member, so that we
9370 can define it as a GTY deletable pointer, which is highly
9371 desirable. A data member could be declared that way, but then the
9372 containing object would implicitly get GTY((user)), which would
9373 prevent us from instantiating freelists as global objects.
9374 Although this way we can create freelist global objects, they're
9375 such thin wrappers that instantiating temporaries at every use
9376 loses nothing and saves permanent storage for the freelist object.
9378 Member functions next, anew, poison and reinit have default
9379 implementations that work for most of the types we're interested
9380 in, but if they don't work for some type, they should be explicitly
9381 specialized. See the comments before them for requirements, and
9382 the example specializations for the tree_list_freelist. */
9384 class freelist
9385 {
9386 /* Return the next object in a chain. We could just do type
9387 punning, but if we access the object with its underlying type, we
9388 avoid strict-aliasing trouble. This needs only work between
9389 poison and reinit. */
9392 /* Return a newly allocated, uninitialized or minimally-initialized
9393 object of type T. Any initialization performed by anew should
9394 either remain across the life of the object and the execution of
9395 poison, or be redone by reinit. */
9398 /* Optionally scribble all over the bits holding the object, so that
9399 they become (mostly?) uninitialized memory. This is called while
9400 preparing to make the object part of the free list. */
9405 #ifdef ENABLE_GC_CHECKING
9406 /* Poison the data, to indicate the data is garbage. */
9409 #endif
9410 /* Let valgrind know the object is free. */
9413 /* Let valgrind know the next portion of the object is available,
9414 but uninitialized. */
9416 }
9418 /* Bring an object that underwent at least one lifecycle after anew
9419 and before the most recent free and poison, back to a usable
9420 state, reinitializing whatever is needed for it to be
9421 functionally equivalent to an object just allocated and returned
9422 by anew. This may poison or clear the next field, used by
9423 freelist housekeeping after poison was called. */
9427 #ifdef ENABLE_GC_CHECKING
9429 #endif
9430 /* Let valgrind know the entire object is available, but
9431 uninitialized. */
9433 }
9435 /* Reference a GTY-deletable pointer that points to the first object
9436 in the free list proper. */
9439 /* Construct a freelist object chaining objects off of HEAD. */
9442 /* Add OBJ to the free object list. The former head becomes OBJ's
9443 successor. */
9445 {
9449 }
9451 /* Take an object from the free list, if one is available, or
9452 allocate a new one. Objects taken from the free list should be
9453 regarded as filled with garbage, except for bits that are
9454 configured to be preserved across free and alloc. */
9456 {
9458 {
9463 }
9464 else
9466 }
9467 };
9469 /* Explicitly specialize the interfaces for freelist<tree_node>: we
9470 want to allocate a TREE_LIST using the usual interface, and ensure
9471 TREE_CHAIN remains functional. Alas, we have to duplicate a bit of
9472 build_tree_list logic in reinit, so this could go out of sync. */
9476 {
9478 }
9480 inline tree
9482 {
9484 }
9488 {
9494 #ifdef ENABLE_GC_CHECKING
9497 /* Poison the data, to indicate the data is garbage. */
9500 #endif
9501 /* Let valgrind know the object is free. */
9503 /* But we still want to use the TREE_CODE and TREE_CHAIN parts. */
9507 #ifdef ENABLE_GC_CHECKING
9509 /* Keep TREE_CHAIN functional. */
9511 #else
9513 #endif
9514 }
9518 {
9521 #ifdef ENABLE_GC_CHECKING
9525 #endif
9527 /* Let valgrind know the entire object is available, but
9528 uninitialized. */
9531 #ifdef ENABLE_GC_CHECKING
9533 #else
9535 #endif
9536 }
9538 /* Point to the first object in the TREE_LIST freelist. */
9540 /* Return the/an actual TREE_LIST freelist. */
9543 {
9545 }
9547 /* Point to the first object in the tinst_level freelist. */
9549 /* Return the/an actual tinst_level freelist. */
9552 {
9554 }
9556 /* Point to the first object in the pending_template freelist. */
9558 /* Return the/an actual pending_template freelist. */
9561 {
9563 }
9565 /* Build the TREE_LIST object out of a split list, store it
9566 permanently, and return it. */
9567 tree
9569 {
9578 }
9582 /* Increment OBJ's refcount unless it is already infinite. */
9585 {
9589 }
9591 /* Release storage for OBJ and node, if it's a TREE_LIST. */
9592 void
9594 {
9598 }
9600 /* Decrement OBJ's refcount if not infinite. If it reaches zero, release
9601 OBJ's DECL and OBJ, and start over with the tinst_level object that
9602 used to be referenced by OBJ's NEXT. */
9603 static void
9605 {
9609 {
9613 }
9614 }
9616 /* Modify PTR so that it points to OBJ, adjusting the refcounts of OBJ
9617 and of the former PTR. Omitting the second argument is equivalent
9618 to passing (T*)NULL; this is allowed because passing the
9619 zero-valued integral constant NULL confuses type deduction and/or
9620 overload resolution. */
9622 static void
9624 {
9628 }
9630 static void
9632 {
9642 /* We are called both from instantiate_decl, where we've already had a
9643 tinst_level pushed, and instantiate_template, where we haven't.
9644 Compensate. */
9646 level = !current_tinst_level
9658 else
9667 }
9670 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
9671 ARGLIST. Valid choices for FNS are given in the cp-tree.def
9672 documentation for TEMPLATE_ID_EXPR. */
9674 tree
9676 {
9683 {
9686 }
9689 {
9692 unknown_type_node,
9694 arglist);
9696 }
9699 }
9701 /* Within the scope of a template class S<T>, the name S gets bound
9702 (in build_self_reference) to a TYPE_DECL for the class, not a
9703 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
9704 or one of its enclosing classes, and that type is a template,
9705 return the associated TEMPLATE_DECL. Otherwise, the original
9706 DECL is returned.
9708 Also handle the case when DECL is a TREE_LIST of ambiguous
9709 injected-class-names from different bases. */
9711 tree
9713 {
9717 /* DR 176: A lookup that finds an injected-class-name (10.2
9718 [class.member.lookup]) can result in an ambiguity in certain cases
9719 (for example, if it is found in more than one base class). If all of
9720 the injected-class-names that are found refer to specializations of
9721 the same class template, and if the name is followed by a
9722 template-argument-list, the reference refers to the class template
9723 itself and not a specialization thereof, and is not ambiguous. */
9725 {
9728 {
9734 }
9737 else
9739 }
9745 }
9747 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
9748 parameters, find the desired type.
9750 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
9752 IN_DECL, if non-NULL, is the template declaration we are trying to
9753 instantiate.
9755 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
9756 the class we are looking up.
9758 Issue error and warning messages under control of COMPLAIN.
9760 If the template class is really a local class in a template
9761 function, then the FUNCTION_CONTEXT is the function in which it is
9762 being instantiated.
9764 ??? Note that this function is currently called *twice* for each
9765 template-id: the first time from the parser, while creating the
9766 incomplete type (finish_template_type), and the second type during the
9767 real instantiation (instantiate_template_class). This is surely something
9768 that we want to avoid. It also causes some problems with argument
9769 coercion (see convert_nontype_argument for more information on this). */
9771 tree
9774 {
9778 tree t;
9781 spec_entry elt;
9782 hashval_t hash;
9785 {
9789 else
9790 {
9797 }
9798 }
9800 {
9803 /* If we are declaring a constructor, say A<T>::A<T>, we will get
9804 an implicit typename for the second A. Deal with it. */
9809 {
9812 }
9813 }
9816 {
9819 }
9821 {
9824 }
9826 {
9829 }
9831 /* Issue an error message if we didn't find a template. */
9833 {
9837 }
9840 /* Make sure it's a user visible template, if it was named by
9841 the user. */
9844 {
9846 {
9850 }
9852 }
9856 /* An alias that just changes the name of a template is equivalent to the
9857 other template, so if any of the arguments are pack expansions, strip
9858 the alias to avoid problems with a pack expansion passed to a non-pack
9859 alias template parameter (DR 1430). */
9864 {
9865 tree parm;
9874 }
9875 else
9876 {
9878 tree gen_tmpl;
9879 tree type_decl;
9887 /* An error occurred while building the template TEMPL, and a
9888 diagnostic has most certainly been emitted for that
9889 already. Let's propagate that error. */
9901 {
9902 /* We've been given an incomplete set of template arguments.
9903 For example, given:
9905 template <class T> struct S1 {
9906 template <class U> struct S2 {};
9907 template <class U> struct S2<U*> {};
9908 };
9910 we will be called with an ARGLIST of `U*', but the
9911 TEMPLATE will be `template <class T> template
9912 <class U> struct S1<T>::S2'. We must fill in the missing
9913 arguments. */
9917 }
9919 /* Now we should have enough arguments. */
9922 /* From here on, we're only interested in the most general
9923 template. */
9925 /* Shortcut looking up the current class scope again. */
9929 {
9940 }
9942 /* Calculate the BOUND_ARGS. These will be the args that are
9943 actually tsubst'd into the definition to create the
9944 instantiation. */
9949 /* We were unable to bind the arguments. */
9952 /* In the scope of a template class, explicit references to the
9953 template class refer to the type of the template, not any
9954 instantiation of it. For example, in:
9956 template <class T> class C { void f(C<T>); }
9958 the `C<T>' is just the same as `C'. Outside of the
9959 class, however, such a reference is an instantiation. */
9963 {
9968 }
9970 /* If we already have this specialization, return it. */
9980 /* If the template's constraints are not satisfied,
9981 then we cannot form a valid type.
9983 Note that the check is deferred until after the hash
9984 lookup. This prevents redundant checks on previously
9985 instantiated specializations. */
9989 {
9991 {
9992 auto_diagnostic_group d;
9995 }
9997 }
10001 /* If the deduced arguments are invalid, then the binding
10002 failed. */
10006 complain))
10013 /* This occurs when the user has tried to define a tagged type
10014 in a scope that forbids it. We emitted an error during the
10015 parse. We didn't complete the bail out then, so here we
10016 are. */
10021 {
10023 /* If the context of the partially instantiated template is
10024 already non-dependent, then we might as well use it. */
10026 else
10027 {
10030 /* Try completing the enclosing context if it's not already so. */
10033 {
10036 {
10037 /* Completion could have caused us to register the desired
10038 specialization already, so check the table again. */
10042 }
10043 }
10044 }
10045 }
10046 else
10055 /* Create the type. */
10057 {
10058 /* The user referred to a specialization of an alias
10059 template represented by GEN_TMPL.
10061 [temp.alias]/2 says:
10063 When a template-id refers to the specialization of an
10064 alias template, it is equivalent to the associated
10065 type obtained by substitution of its
10066 template-arguments for the template-parameters in the
10067 type-id of the alias template. */
10070 /* Note that the call above (by indirectly calling
10071 register_specialization in tsubst_decl) registers the
10072 TYPE_DECL representing the specialization of the alias
10073 template. So next time someone substitutes ARGLIST for
10074 the template parms into the alias template (GEN_TMPL),
10075 she'll get that TYPE_DECL back. */
10079 }
10081 {
10083 {
10094 }
10095 else
10096 {
10097 /* We don't want to call start_enum for this type, since
10098 the values for the enumeration constants may involve
10099 template parameters. And, no one should be interested
10100 in the enumeration constants for such a type. */
10103 }
10107 }
10109 {
10110 /* Lambda closures are regenerated in tsubst_lambda_expr, not
10111 instantiated here. */
10119 /* A local class. Make sure the decl gets registered properly. */
10126 /* This instantiation is another name for the primary
10127 template type. Set the TYPE_CANONICAL field
10128 appropriately. */
10132 }
10133 else
10136 /* If we called start_enum or pushtag above, this information
10137 will already be set up. */
10140 {
10147 }
10150 /* Although GEN_TMPL is the TEMPLATE_DECL, it has the same value
10151 of export flag. We want to propagate this because it might
10152 be a friend declaration that pushes a new hidden binding. */
10156 {
10162 {
10165 }
10166 }
10170 {
10174 {
10175 tree attributes
10183 }
10184 }
10186 /* Let's consider the explicit specialization of a member
10187 of a class template specialization that is implicitly instantiated,
10188 e.g.:
10189 template<class T>
10190 struct S
10191 {
10192 template<class U> struct M {}; //#0
10193 };
10195 template<>
10196 template<>
10197 struct S<int>::M<char> //#1
10198 {
10199 int i;
10200 };
10201 [temp.expl.spec]/4 says this is valid.
10203 In this case, when we write:
10204 S<int>::M<char> m;
10206 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
10207 the one of #0.
10209 When we encounter #1, we want to store the partial instantiation
10210 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
10212 For all cases other than this "explicit specialization of member of a
10213 class template", we just want to store the most general template into
10214 the CLASSTYPE_TI_TEMPLATE of M.
10216 This case of "explicit specialization of member of a class template"
10217 only happens when:
10218 1/ the enclosing class is an instantiation of, and therefore not
10219 the same as, the context of the most general template, and
10220 2/ we aren't looking at the partial instantiation itself, i.e.
10221 the innermost arguments are not the same as the innermost parms of
10222 the most general template.
10224 So it's only when 1/ and 2/ happens that we want to use the partial
10225 instantiation of the member template in lieu of its most general
10226 template. */
10230 /* the enclosing class must be an instantiation... */
10233 {
10237 tree partial_inst_args =
10244 use_partial_inst_tmpl =
10245 /*...and we must not be looking at the partial instantiation
10246 itself. */
10248 partial_inst_args);
10249 }
10252 /* This case is easy; there are no member templates involved. */
10254 else
10255 {
10256 /* This is a full instantiation of a member template. Find
10257 the partial instantiation of which this is an instance. */
10259 /* Temporarily reduce by one the number of levels in the ARGLIST
10260 so as to avoid comparing the last set of arguments. */
10262 /* We don't use COMPLAIN in the following call because this isn't
10263 the immediate context of deduction. For instance, tf_partial
10264 could be set here as we might be at the beginning of template
10265 argument deduction when any explicitly specified template
10266 arguments are substituted into the function type. tf_partial
10267 could lead into trouble because we wouldn't find the partial
10268 instantiation that might have been created outside tf_partial
10269 context, because the levels of template parameters wouldn't
10270 match, because in a tf_partial context, tsubst doesn't reduce
10271 TEMPLATE_PARM_LEVEL. */
10274 /* FOUND is either a proper class type, or an alias
10275 template specialization. In the later case, it's a
10276 TYPE_DECL, resulting from the substituting of arguments
10277 for parameters in the TYPE_DECL of the alias template
10278 done earlier. So be careful while getting the template
10279 of FOUND. */
10281 ? found
10288 {
10289 /* If this partial instantiation is specialized, we want to
10290 use it for hash table lookup. */
10294 }
10295 }
10297 /* Build template info for the new specialization. */
10307 /* Note this use of the partial instantiation so we can check it
10308 later in maybe_process_partial_specialization. */
10316 /* Now that the type has been registered on the instantiations
10317 list, we set up the enumerators. Because the enumeration
10318 constants may involve the enumeration type itself, we make
10319 sure to register the type first, and then create the
10320 constants. That way, doing tsubst_expr for the enumeration
10321 constants won't result in recursive calls here; we'll find
10322 the instantiation and exit above. */
10326 /* If the type makes use of template parameters, the
10327 code that generates debugging information will crash. */
10330 /* Possibly limit visibility based on template args. */
10337 }
10338 }
10340 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
10342 tree
10344 {
10353 /* The type of the expression is NULL_TREE since the template-id could refer
10354 to an explicit or partial specialization. */
10356 }
10358 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR if it's
10359 not dependent. */
10361 tree
10363 {
10367 /* If the template or arguments are dependent, then we
10368 can't resolve the TEMPLATE_ID_EXPR yet. */
10374 {
10376 {
10377 auto_diagnostic_group d;
10380 }
10382 }
10385 }
10387 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
10388 TARGS template args, and instantiate it if it's not dependent. */
10390 tree
10392 tsubst_flags_t complain)
10393 {
10397 /* We may be called while doing a partial substitution, but the
10398 type of the variable template may be auto, in which case we
10399 will call do_auto_deduction in mark_used (which clears tf_partial)
10400 and the auto must be properly reduced at that time for the
10401 deduction to work. */
10406 }
10408 /* If the set of template parameters PARMS contains a template parameter
10409 at the given LEVEL and INDEX, then return this parameter. Otherwise
10410 return NULL_TREE. */
10412 static tree
10414 {
10423 }
10425 /* Return the TREE_LIST for the template parameter from PARMS that positionally
10426 corresponds to the template parameter PARM, or else return NULL_TREE. */
10428 static tree
10430 {
10434 }
10436 /* As above, but pull out the actual parameter. */
10438 static tree
10440 {
10446 /* As in template_parm_to_arg. */
10449 else
10454 }
10455 \f
10456 struct pair_fn_data
10457 {
10458 tree_fn_t fn;
10459 tree_fn_t any_fn;
10461 /* True when we should also visit template parameters that occur in
10462 non-deduced contexts. */
10465 };
10467 /* Called from for_each_template_parm via walk_tree. */
10469 static tree
10471 {
10478 #define WALK_SUBTREE(NODE) \
10479 do \
10480 { \
10481 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
10482 pfd->include_nondeduced_p, \
10483 pfd->any_fn); \
10484 if (result) goto out; \
10485 } \
10486 while (0)
10496 {
10500 /* Fall through. */
10506 else
10516 /* Since we're not going to walk subtrees, we have to do this
10517 explicitly here. */
10519 /* Fall through. */
10522 /* Check the return type. */
10525 /* Check the parameter types. Since default arguments are not
10526 instantiated until they are needed, the TYPE_ARG_TYPES may
10527 contain expressions that involve template parameters. But,
10528 no-one should be looking at them yet. And, once they're
10529 instantiated, they don't contain template parameters, so
10530 there's no point in looking at them then, either. */
10531 {
10532 tree parm;
10537 /* Since we've already handled the TYPE_ARG_TYPES, we don't
10538 want walk_tree walking into them itself. */
10540 }
10543 {
10547 }
10563 {
10566 }
10589 /* Record template parameters such as `T' inside `TT<T>'. */
10591 /* Fall through. */
10603 /* A template template parameter is encountered. */
10607 /* Already substituted template template parameter */
10612 /* A template-id in a TYPENAME_TYPE might be a deduced context after
10613 partial instantiation. */
10620 /* If there's no type, then this thing must be some expression
10621 involving template parameters. */
10631 /* These are non-deduced contexts. */
10653 }
10655 #undef WALK_SUBTREE
10657 /* We didn't find any template parameters we liked. */
10658 out:
10660 }
10662 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
10663 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
10664 call FN with the parameter and the DATA.
10665 If FN returns nonzero, the iteration is terminated, and
10666 for_each_template_parm returns 1. Otherwise, the iteration
10667 continues. If FN never returns a nonzero value, the value
10668 returned by for_each_template_parm is 0. If FN is NULL, it is
10669 considered to be the function which always returns 1.
10671 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
10672 parameters that occur in non-deduced contexts. When false, only
10673 visits those template parameters that can be deduced. */
10675 static tree
10679 tree_fn_t any_fn)
10680 {
10682 tree result;
10684 /* Set up. */
10690 /* Walk the tree. (Conceptually, we would like to walk without
10691 duplicates, but for_each_template_parm_r recursively calls
10692 for_each_template_parm, so we would need to reorganize a fair
10693 bit to use walk_tree_without_duplicates, so we keep our own
10694 visited list.) */
10697 else
10700 for_each_template_parm_r,
10704 /* Clean up. */
10706 {
10709 }
10712 }
10714 struct find_template_parameter_info
10715 {
10719 {}
10725 tree ctx_parms;
10732 };
10734 /* Appends the declaration of T to the list in DATA. */
10736 static int
10738 {
10741 /* Template parameters declared within the expression are not part of
10742 the parameter mapping. For example, in this concept:
10744 template<typename T>
10745 concept C = requires { <expr> } -> same_as<int>;
10747 the return specifier same_as<int> declares a new decltype parameter
10748 that must not be part of the parameter mapping. The same is true
10749 for generic lambda parameters, lambda template parameters, etc. */
10757 /* We want the underlying TEMPLATE_TEMPLATE_PARM, not the
10758 BOUND_TEMPLATE_TEMPLATE_PARM itself. */
10761 /* This template parameter might be an argument to a cached dependent
10762 specalization that was formed earlier inside some other template, in
10763 which case the parameter is not among the ones that are in-scope.
10764 Look in CTX_PARMS to find the corresponding in-scope template
10765 parameter, and use it instead. */
10769 /* Arguments like const T yield parameters like const T. This means that
10770 a template-id like X<T, const T> would yield two distinct parameters:
10771 T and const T. Adjust types to their unqualified versions. */
10775 {
10776 /* Append T to PARM_LIST. */
10780 }
10782 /* Verify the parameter we found has a valid index. */
10784 {
10790 }
10793 }
10795 /* Ensure that we recursively examine certain terms that are not normally
10796 visited in for_each_template_parm_r. */
10798 static int
10800 {
10803 #define WALK_SUBTREE(NODE) \
10804 do \
10805 { \
10806 for_each_template_parm (NODE, keep_template_parm, data, \
10807 &ftpi->visited, true, \
10808 any_template_parm_r); \
10809 } \
10810 while (0)
10812 /* A mention of a member alias/typedef is a use of all of its template
10813 arguments, including those from the enclosing class, so we don't use
10814 alias_template_specialization_p here. */
10820 {
10822 /* Type constraints of a placeholder type may contain parameters. */
10829 /* Search through references to variable templates. */
10839 /* If T is a member template that shares template parameters with
10840 ctx_parms, we need to mark all those parameters for mapping.
10841 To that end, it should suffice to just walk the DECL_CONTEXT of
10842 the template (assuming the template is not overly general). */
10847 {
10848 /* Look in the parms and body. */
10852 }
10857 /* The conversion-type-id of a conversion operator may be dependent. */
10868 }
10870 /* Keep walking. */
10872 }
10874 /* Look through T for template parameters. */
10876 tree
10878 {
10881 any_template_parm_r);
10882 }
10884 /* As above, but also recursively look into the default arguments of template
10885 parameters we found. Used for alias CTAD. */
10887 tree
10889 {
10892 /* Since newly found parms are added to the end of the list, we
10893 can just walk it until we reach the end. */
10895 {
10900 }
10902 }
10904 /* True if PARM was found by a previous call to find_in. PARM can be a
10905 TREE_LIST, a DECL_TEMPLATE_PARM_P, or a TEMPLATE_PARM_P. */
10907 bool
10909 {
10914 else
10918 }
10920 /* Returns a list of unique template parameters found within T, where CTX_PARMS
10921 are the template parameters in scope. */
10923 tree
10925 {
10932 }
10934 /* Returns true if T depends on any template parameter. */
10936 bool
10938 {
10942 /* Namespaces can't depend on any template parameters. */
10958 else
10960 }
10962 /* Returns true if T depends on any template parameter with level LEVEL. */
10964 bool
10966 {
10969 }
10971 /* Returns true if the signature of DECL depends on any template parameter from
10972 its enclosing class. */
10974 static bool
10976 {
10980 else
10989 {
10992 {
10997 template_parm_outer_level,
11007 }
11008 }
11012 }
11014 /* Returns true if the constraints of DECL depend on any template parameters
11015 from its enclosing scope. */
11017 bool
11019 {
11030 }
11032 /* Returns TRUE iff INST is an instantiation we don't need to do in an
11033 ill-formed translation unit, i.e. a variable or function that isn't
11034 usable in a constant expression. */
11038 {
11044 }
11046 /* Returns TRUE iff we should refuse to instantiate DECL because it's
11047 neglectable and instantiated from within an erroneous instantiation. */
11049 static bool
11051 {
11057 /* Avoid instantiating members of an ill-formed class. */
11058 bool refuse
11063 {
11068 }
11071 {
11072 /* Don't warn about it not being defined. */
11074 tree clone;
11077 }
11079 }
11087 /* We're starting to instantiate D; record the template instantiation context
11088 at LOC for diagnostics and to restore it later. */
11090 bool
11092 {
11096 {
11097 /* Tell error.cc not to try to instantiate any templates. */
11100 "template instantiation depth exceeds maximum of %d"
11102 max_tinst_depth);
11104 }
11106 /* If the current instantiation caused problems, don't let it instantiate
11107 anything else. Do allow deduction substitution and decls usable in
11108 constant expressions. */
11110 {
11111 /* Avoid no_linkage_errors and unused function (and all other)
11112 warnings for this decl. */
11115 }
11117 /* When not -quiet, dump template instantiations other than functions, since
11118 announce_function will take care of those. */
11140 }
11142 /* We're starting substitution of TMPL<ARGS>; record the template
11143 substitution context for diagnostics and to restore it later. */
11145 bool
11147 {
11149 }
11151 /* We're starting to instantiate D; record INPUT_LOCATION and the
11152 template instantiation context for diagnostics and to restore it
11153 later. */
11155 bool
11157 {
11159 }
11161 /* Likewise, but record LOC as the program location. */
11163 bool
11165 {
11168 }
11170 /* We're done instantiating this template; return to the instantiation
11171 context. */
11173 void
11175 {
11176 /* Restore the filename and line number stashed away when we started
11177 this instantiation. */
11181 }
11183 /* We're instantiating a deferred template; restore the template
11184 instantiation context in which the instantiation was requested, which
11185 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
11187 static tree
11189 {
11201 }
11203 /* Returns the TINST_LEVEL which gives the original instantiation
11204 context. */
11208 {
11214 }
11216 /* True iff T is a friend function declaration that is not itself a template
11217 and is not defined in a class template. */
11219 bool
11221 {
11224 {
11228 /* DECL_FRIEND_CONTEXT is set for a friend defined in class. */
11231 /* Non-templated friends in a class template are still represented with a
11232 TEMPLATE_DECL; check that its primary template is the befriending
11233 class. Note that DECL_PRIMARY_TEMPLATE is null for
11234 template <class T> friend A<T>::f(); */
11238 }
11239 else
11241 }
11243 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
11244 vector of template arguments, as for tsubst.
11246 Returns an appropriate tsubst'd friend declaration. */
11248 static tree
11250 {
11251 tree new_friend;
11256 /* This was a friend declared with an explicit template
11257 argument list, e.g.:
11259 friend void f<>(T);
11261 to indicate that f was a template instantiation, not a new
11262 function declaration. Now, we have to figure out what
11263 instantiation of what template. */
11264 {
11266 tree new_args;
11267 tree tmpl;
11270 /* Friend functions are looked up in the containing namespace scope.
11271 We must enter that scope, to avoid finding member functions of the
11272 current class with same name. */
11286 tsk_none);
11288 }
11294 /* The NEW_FRIEND will look like an instantiation, to the
11295 compiler, but is not an instantiation from the point of view of
11296 the language. For example, we might have had:
11298 template <class T> struct S {
11299 template <class U> friend void f(T, U);
11300 };
11302 Then, in S<int>, template <class U> void f(int, U) is not an
11303 instantiation of anything. */
11307 {
11313 /* Substitute TEMPLATE_PARMS_CONSTRAINTS so that parameter levels will
11314 match in decls_match. */
11319 {
11321 /* As well as each TEMPLATE_PARM_CONSTRAINTS. */
11323 tf_warning_or_error);
11324 }
11325 }
11327 /* The mangled name for the NEW_FRIEND is incorrect. The function
11328 is not a template instantiation and should not be mangled like
11329 one. Therefore, we forget the mangling here; we'll recompute it
11330 later if we need it. */
11332 {
11335 }
11338 {
11339 tree old_decl;
11340 tree ns;
11342 /* We must save some information from NEW_FRIEND before calling
11343 duplicate decls since that function will free NEW_FRIEND if
11344 possible. */
11348 (new_friend_template_info
11355 {
11356 /* This declaration is a `primary' template. */
11361 }
11363 /* Only define a constrained hidden friend when satisfied. */
11366 /* Inside pushdecl_namespace_level, we will push into the
11367 current namespace. However, the friend function should go
11368 into the namespace of the template. */
11378 {
11379 /* This new friend declaration matched an existing
11380 declaration. For example, given:
11382 template <class T> void f(T);
11383 template <class U> class C {
11384 template <class T> friend void f(T) {}
11385 };
11387 the friend declaration actually provides the definition
11388 of `f', once C has been instantiated for some type. So,
11389 old_decl will be the out-of-class template declaration,
11390 while new_friend is the in-class definition.
11392 But, if `f' was called before this point, the
11393 instantiation of `f' will have DECL_TI_ARGS corresponding
11394 to `T' but not to `U', references to which might appear
11395 in the definition of `f'. Previously, the most general
11396 template for an instantiation of `f' was the out-of-class
11397 version; now it is the in-class version. Therefore, we
11398 run through all specialization of `f', adding to their
11399 DECL_TI_ARGS appropriately. In particular, they need a
11400 new set of outer arguments, corresponding to the
11401 arguments for this class instantiation.
11403 The same situation can arise with something like this:
11405 friend void f(int);
11406 template <class T> class C {
11407 friend void f(T) {}
11408 };
11410 when `C<int>' is instantiated. Now, `f(int)' is defined
11411 in the class. */
11414 /* On the other hand, if the in-class declaration does
11415 *not* provide a definition, then we don't want to alter
11416 existing definitions. We can just leave everything
11417 alone. */
11418 ;
11419 else
11420 {
11424 /* Overwrite whatever template info was there before, if
11425 any, with the new template information pertaining to
11426 the declaration. */
11430 {
11431 /* We should have called reregister_specialization in
11432 duplicate_decls. */
11437 /* Instantiate it if the global has already been used. */
11441 }
11442 else
11443 {
11444 tree t;
11446 /* Indicate that the old function template is a partial
11447 instantiation. */
11455 /* Reassign any specializations already in the hash table
11456 to the new more general template, and add the
11457 additional template args. */
11461 {
11463 spec_entry elt;
11475 register_specialization
11478 }
11480 }
11481 }
11483 /* The information from NEW_FRIEND has been merged into OLD_DECL
11484 by duplicate_decls. */
11486 }
11488 /* We've just introduced a namespace-scope function in the purview
11489 without necessarily having opened the enclosing namespace, so
11490 make sure the namespace is in the purview now too. */
11495 }
11496 else
11497 {
11501 /* In the code
11502 template <class T> class C {
11503 template <class U> friend void C1<U>::f (); // case 1
11504 friend void C2<T>::f (); // case 2
11505 };
11506 we only need to make sure CONTEXT is a complete type for
11507 case 2. To distinguish between the two cases, we note that
11508 CONTEXT of case 1 remains dependent type after tsubst while
11509 this isn't true for case 2. */
11519 {
11521 /* do_friend adds the TEMPLATE_DECL for any member friend
11522 template even if it isn't a member template, i.e.
11523 template <class T> friend A<T>::f();
11524 Look through it in that case. */
11528 /* Check to see that the declaration is really present, and,
11529 possibly obtain an improved declaration. */
11534 }
11535 }
11538 }
11540 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
11541 template arguments, as for tsubst.
11543 Returns an appropriate tsubst'd friend type or error_mark_node on
11544 failure. */
11546 static tree
11548 {
11549 tree tmpl;
11552 {
11555 }
11560 else
11561 {
11564 }
11570 {
11571 /* The friend template has already been declared. Just
11572 check to see that the declarations match, and install any new
11573 default parameters. We must tsubst the default parameters,
11574 of course. We only need the innermost template parameters
11575 because that is all that redeclare_class_template will look
11576 at. */
11579 {
11583 tf_warning_or_error);
11593 }
11594 }
11595 else
11596 {
11597 /* The friend template has not already been declared. In this
11598 case, the instantiation of the template class will cause the
11599 injection of this template into the namespace scope. */
11603 {
11604 /* The new TMPL is not an instantiation of anything, so we
11605 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
11606 for the new type because that is supposed to be the
11607 corresponding template decl, i.e., TMPL. */
11614 /* Substitute into and set the constraints on the new declaration. */
11616 {
11624 }
11626 /* Inject this template into the enclosing namspace scope. */
11628 }
11629 }
11633 else
11637 }
11639 /* Returns zero if TYPE cannot be completed later due to circularity.
11640 Otherwise returns one. */
11642 static int
11644 {
11654 else
11656 }
11661 /* Instantiate the contract statement. */
11663 static tree
11665 tree in_decl)
11666 {
11672 /* Rebuild the result variable. */
11674 {
11682 /* Make sure the postcondition is valid. */
11688 /* Make the variable available for lookup. */
11690 }
11692 /* Instantiate the condition. If the return type is undeduced, process
11693 the expression as if inside a template to avoid spurious type errors. */
11703 /* And the comment. */
11708 }
11710 /* Update T by instantiating its contract attribute. */
11712 static void
11715 {
11716 /* For non-specializations, adjust the current declaration to the most general
11717 version of in_decl. Because we defer the instantiation of contracts as long
11718 as possible, they are still written in terms of the parameters (and return
11719 type) of the most general template. */
11726 /* Get the contract to be instantiated. */
11729 /* Use the complete set of template arguments for instantiation. The
11730 contract may not have been instantiated and still refer to outer levels
11731 of template parameters. */
11734 /* For member functions, make this available for semantic analysis. */
11738 {
11742 }
11749 /* Rebuild the attribute. */
11751 }
11753 /* Rebuild the attribute list for DECL, substituting into contracts
11754 as needed. */
11756 void
11758 {
11761 {
11764 }
11766 }
11768 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
11769 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
11771 static tree
11774 {
11777 /* Note that contract attributes are never substituted from this function.
11778 Their instantiation is triggered by regenerate_from_template_decl when
11779 we instantiate the body of the function. */
11787 {
11794 clauses
11798 else
11800 }
11804 {
11815 {
11819 {
11821 {
11829 }
11830 else
11831 {
11835 {
11836 bool allow_string
11848 {
11849 location_t loc
11851 match_loc);
11857 "integer expression or string "
11859 else
11863 }
11866 {
11867 location_t loc
11869 match_loc);
11873 }
11875 }
11876 }
11877 }
11878 }
11880 }
11881 /* If the first attribute argument is an identifier, don't
11882 pass it through tsubst. Attributes like mode, format,
11883 cleanup and several target specific attributes expect it
11884 unmodified. */
11886 {
11887 tree chain
11891 }
11893 {
11894 /* An attribute pack expansion. */
11903 {
11907 }
11909 }
11910 else
11918 }
11920 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
11921 unchanged or a new TREE_LIST chain. */
11923 static tree
11926 {
11931 {
11935 }
11939 {
11942 {
11945 {
11951 }
11952 }
11954 }
11957 }
11959 /* Apply any attributes which had to be deferred until instantiation
11960 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
11961 ARGS, COMPLAIN, IN_DECL are as tsubst. Returns true normally,
11962 false on error. */
11964 static bool
11967 {
11968 tree t;
11975 {
11979 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
11980 to our attributes parameter. */
11982 }
11983 else
11984 {
11986 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
11987 lookup_template_class_1, and should be preserved. */
11991 }
11993 /* save_template_attributes puts the dependent attributes at the beginning of
11994 the list; find the non-dependent ones. */
12000 /* Apply any non-dependent attributes. */
12006 /* And then any dependent ones. */
12010 {
12015 {
12018 }
12021 }
12023 /* cplus_decl_attributes can add some attributes implicitly. For templates,
12024 those attributes should have been added already when those templates were
12025 parsed, and shouldn't be added based on from which context they are
12026 first time instantiated. */
12029 optimization_default_node);
12032 NULL);
12038 }
12040 /* The template TMPL is being instantiated with the template arguments TARGS.
12041 Perform the access checks that we deferred when parsing the template. */
12043 static void
12045 {
12055 {
12063 /* Make access check error messages point to the location
12064 of the use of the typedef. */
12068 }
12069 }
12071 tree
12073 {
12077 tree typedecl;
12078 tree pbinfo;
12079 tree base_list;
12081 tree fn_context;
12091 /* Figure out which template is being instantiated. */
12095 /* Mark the type as in the process of being defined. */
12098 /* We may be in the middle of deferred access check. Disable
12099 it now. */
12102 /* Determine what specialization of the original template to
12103 instantiate. */
12108 {
12109 /* This TYPE is actually an instantiation of a partial
12110 specialization. We replace the innermost set of ARGS with
12111 the arguments appropriate for substitution. For example,
12112 given:
12114 template <class T> struct S {};
12115 template <class T> struct S<T*> {};
12117 and supposing that we are instantiating S<int*>, ARGS will
12118 presently be {int*} -- but we need {int}. */
12121 }
12122 else
12123 {
12126 }
12128 /* If the template we're instantiating is incomplete, then clearly
12129 there's nothing we can do. */
12131 {
12132 /* We can try again later. */
12135 }
12137 /* If we've recursively instantiated too many templates, stop. */
12145 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
12150 else
12151 {
12154 }
12158 /* Use #pragma pack from the template context. */
12164 /* Set the input location to the most specialized template definition.
12165 This is needed if tsubsting causes an error. */
12179 {
12182 /* Adjust visibility for template arguments. */
12184 }
12190 /* We should never instantiate a nested class before its enclosing
12191 class; we need to look up the nested class by name before we can
12192 instantiate it, and that lookup should instantiate the enclosing
12193 class. */
12198 /* Defer access checking while we substitute into the types named in
12199 the base-clause. */
12202 {
12203 tree pbase_binfo;
12206 /* Substitute into each of the bases to determine the actual
12207 basetypes. */
12209 {
12210 tree base;
12216 {
12217 expanded_bases =
12224 }
12227 {
12229 /* Extract the already-expanded base class. */
12231 else
12232 /* Substitute to figure out the base class. */
12234 NULL_TREE);
12242 }
12243 }
12245 /* The list is now in reverse order; correct that. */
12247 }
12248 /* Now call xref_basetypes to set up all the base-class
12249 information. */
12257 /* Now that our base classes are set up, enter the scope of the
12258 class, so that name lookups into base classes, etc. will work
12259 correctly. This is precisely analogous to what we do in
12260 begin_class_definition when defining an ordinary non-template
12261 class, except we also need to push the enclosing classes. */
12264 /* Now check accessibility of the types named in its base-clause,
12265 relative to the scope of the class. */
12268 /* A vector to hold members marked with attribute used. */
12271 /* Now members are processed in the order of declaration. */
12274 {
12278 {
12280 {
12282 /* A closure type for a lambda in an NSDMI or default argument.
12283 Ignore it; it will be regenerated when needed. */
12286 /* If the member is a class template, we've
12287 already substituted its type. */
12297 {
12300 /* Now, install the tag. We don't use pushtag
12301 because that does too much work -- creating an
12302 implicit typedef, which we've already done. */
12307 }
12308 }
12310 {
12311 tree r;
12321 /* Instantiate members marked with attribute used. */
12327 }
12330 /* A closure type for a lambda in an NSDMI or default argument.
12332 else
12333 {
12334 /* Build new TYPE_FIELDS. */
12338 {
12339 tree r;
12344 /* The file and line for this declaration, to
12345 assist in error message reporting. Since we
12346 called push_tinst_level above, we don't need to
12347 restore these. */
12357 {
12358 /* A capture pack became multiple fields. */
12361 }
12364 {
12368 {
12369 /* In [temp.inst]:
12371 [t]he initialization (and any associated
12372 side-effects) of a static data member does
12373 not occur unless the static data member is
12374 itself used in a way that requires the
12375 definition of the static data member to
12376 exist.
12378 Therefore, we do not substitute into the
12379 initialized for the static data member here. */
12380 finish_static_data_member_decl
12386 /* Instantiate members marked with attribute used. */
12389 }
12391 {
12392 /* Determine whether R has a valid type and can be
12393 completed later. If R is invalid, then its type
12394 is replaced by error_mark_node. */
12400 {
12401 /* If R's type couldn't be completed and
12402 it isn't a flexible array member (whose
12403 type is incomplete by definition) give
12404 an error. */
12407 }
12412 {
12415 }
12419 }
12421 /* If it is a TYPE_DECL for a class-scoped
12422 ENUMERAL_TYPE, such a thing will already have
12423 been added to the field list by tsubst_enum
12424 in finish_member_declaration case above. */
12428 {
12431 }
12432 }
12433 }
12434 }
12435 }
12436 else
12437 {
12440 {
12441 /* Build new CLASSTYPE_FRIEND_CLASSES. */
12445 {
12446 /* template <class T> friend class C; */
12448 }
12450 {
12451 /* template <class T> friend class C::D; */
12456 }
12459 {
12460 /* This could be either
12462 friend class T::C;
12464 when dependent_type_p is false or
12466 template <class U> friend class T::C;
12468 otherwise. */
12469 /* Bump processing_template_decl in case this is something like
12470 template <class T> friend struct A<T>::B. */
12475 }
12477 /* friend class C<T>; */
12481 /* Otherwise it's
12483 friend class C;
12485 where C is already declared or
12487 friend class C<int>;
12489 We don't have to do anything in these cases. */
12493 }
12494 else
12495 {
12496 /* Build new DECL_FRIENDLIST. */
12497 tree r;
12499 /* The file and line for this declaration, to
12500 assist in error message reporting. Since we
12501 called push_tinst_level above, we don't need to
12502 restore these. */
12506 {
12509 }
12514 {
12517 }
12518 }
12519 }
12520 }
12523 {
12524 /* Restore these before substituting into the lambda capture
12525 initializers. */
12528 }
12530 /* Set the file and line number information to whatever is given for
12531 the class itself. This puts error messages involving generated
12532 implicit functions at a predictable point, and the same point
12533 that would be used for non-template classes. */
12540 /* Remember if instantiating this class ran into errors, so we can avoid
12541 instantiating member functions in limit_bad_template_recursion. We set
12542 this flag even if the problem was in another instantiation triggered by
12543 this one, as that will likely also cause trouble for member functions. */
12547 /* We don't instantiate default arguments for member functions. 14.7.1:
12549 The implicit instantiation of a class template specialization causes
12550 the implicit instantiation of the declarations, but not of the
12551 definitions or default arguments, of the class member functions,
12552 member classes, static data members and member templates.... */
12557 /* Now that we've gone through all the members, instantiate those
12558 marked with attribute used. We must do this in the context of
12559 the class -- not the context we pushed from, as that might be
12560 inside a template and change the behaviour of mark_used. */
12570 /* The vtable for a template class can be emitted in any translation
12571 unit in which the class is instantiated. When there is no key
12572 method, however, finish_struct_1 will already have added TYPE to
12573 the keyed_classes. */
12578 }
12580 tree
12582 {
12583 tree r;
12589 else
12590 {
12596 }
12599 }
12601 /* Given a function parameter pack TMPL_PARM and some function parameters
12602 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
12603 and set *SPEC_P to point at the next point in the list. */
12605 tree
12607 {
12608 /* Collect all of the extra "packed" parameters into an
12609 argument pack. */
12610 tree argpack;
12621 {
12622 /* The instantiation is still a parameter pack; don't wrap it in a
12623 NONTYPE_ARGUMENT_PACK. */
12626 }
12627 else
12628 {
12629 /* Fill in PARMVEC with all of the parameters. */
12633 {
12639 }
12641 /* Build the argument packs. */
12643 }
12647 }
12649 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
12650 NONTYPE_ARGUMENT_PACK. */
12652 static tree
12654 {
12656 }
12658 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
12659 pack expansion with no extra args, 2 if it has extra args, or 0
12660 if it is not a pack expansion. */
12662 static int
12664 {
12666 /* We're being called before this happens in tsubst_pack_expansion. */
12673 /* A decl pack is itself an expansion. */
12680 }
12683 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
12685 static tree
12687 {
12694 }
12696 /* This is a subroutine of tsubst_pack_expansion.
12698 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
12699 mechanism to store the (non complete list of) arguments of the
12700 substitution and return a non substituted pack expansion, in order
12701 to wait for when we have enough arguments to really perform the
12702 substitution. */
12704 static bool
12706 tree parm_packs,
12709 {
12714 /* If one pack has an expansion and another pack has a normal
12715 argument or if one pack has an empty argument and an another
12716 one hasn't then tsubst_pack_expansion cannot perform the
12717 substitution and need to fall back on the
12718 PACK_EXPANSION_EXTRA mechanism. */
12722 {
12723 /* If all the actual packs are pack expansions, we can still
12724 subsitute directly. */
12726 {
12736 }
12738 }
12741 {
12745 parm_pack;
12747 {
12752 /* We can't substitute a pack expansion with extra args into
12753 our pattern. */
12757 else
12759 }
12762 {
12765 }
12766 }
12768 }
12770 /* [temp.variadic]/6 says that:
12772 The instantiation of a pack expansion [...]
12773 produces a list E1,E2, ..., En, where N is the number of elements
12774 in the pack expansion parameters.
12776 This subroutine of tsubst_pack_expansion produces one of these Ei.
12778 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
12779 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
12780 PATTERN, and each TREE_VALUE is its corresponding argument pack.
12781 INDEX is the index 'i' of the element Ei to produce. ARGS,
12782 COMPLAIN, and IN_DECL are the same parameters as for the
12783 tsubst_pack_expansion function.
12785 The function returns the resulting Ei upon successful completion,
12786 or error_mark_node.
12788 Note that this function possibly modifies the ARGS parameter, so
12789 it's the responsibility of the caller to restore it. */
12791 static tree
12793 tree parm_packs,
12795 tree args /* This parm gets
12797 tsubst_flags_t complain,
12798 tree in_decl)
12799 {
12800 tree t;
12803 /* For each parameter pack, change the substitution of the parameter
12804 pack to the ith argument in its argument pack, then expand the
12805 pattern. */
12807 {
12812 ith_elem_is_expansion |=
12815 /* Select the Ith argument from the pack. */
12819 {
12821 {
12826 }
12827 else
12829 }
12830 else
12831 {
12836 {
12838 /* Update the corresponding argument. */
12840 }
12841 else
12842 /* Re-use the ARGUMENT_PACK_SELECT. */
12844 }
12846 }
12848 /* Substitute into the PATTERN with the (possibly altered)
12849 arguments. */
12851 /* Expanding a fixed parameter pack from
12852 coerce_template_parameter_pack. */
12858 else
12859 {
12862 /* When expanding the fake auto... pack expansion from add_capture, we
12863 need to mark that the expansion is no longer a pack. */
12865 }
12867 /* If the Ith argument pack element is a pack expansion, then
12868 the Ith element resulting from the substituting is going to
12869 be a pack expansion as well. */
12874 }
12876 /* When the unexpanded parameter pack in a fold expression expands to an empty
12877 sequence, the value of the expression is as follows; the program is
12878 ill-formed if the operator is not listed in this table.
12880 && true
12881 || false
12882 , void() */
12884 tree
12886 {
12890 {
12899 }
12905 }
12907 /* Given a fold-expression T and a current LEFT and RIGHT operand,
12908 form an expression that combines the two terms using the
12909 operator of T. */
12911 static tree
12913 {
12918 // Handle compound assignment operators.
12925 {
12934 complain);
12935 }
12936 }
12938 /* Substitute ARGS into the pack of a fold expression T. */
12942 {
12944 }
12946 /* Substitute ARGS into the pack of a fold expression T. */
12950 {
12952 }
12954 /* Expand a PACK of arguments into a grouped as left fold.
12955 Given a pack containing elements A0, A1, ..., An and an
12956 operator @, this builds the expression:
12958 ((A0 @ A1) @ A2) ... @ An
12960 Note that PACK must not be empty.
12962 The operator is defined by the original fold expression T. */
12964 static tree
12966 {
12969 {
12972 }
12974 }
12976 /* Substitute into a unary left fold expression. */
12978 static tree
12980 tree in_decl)
12981 {
12986 {
12990 }
12993 else
12995 }
12997 /* Substitute into a binary left fold expression.
12999 Do ths by building a single (non-empty) vector of argumnts and
13000 building the expression from those elements. */
13002 static tree
13004 tree in_decl)
13005 {
13014 {
13019 }
13027 }
13029 /* Expand a PACK of arguments into a grouped as right fold.
13030 Given a pack containing elementns A0, A1, ..., and an
13031 operator @, this builds the expression:
13033 A0@ ... (An-2 @ (An-1 @ An))
13035 Note that PACK must not be empty.
13037 The operator is defined by the original fold expression T. */
13039 tree
13041 {
13042 // Build the expression.
13046 {
13049 }
13051 }
13053 /* Substitute into a unary right fold expression. */
13055 static tree
13057 tree in_decl)
13058 {
13063 {
13067 }
13070 else
13072 }
13074 /* Substitute into a binary right fold expression.
13076 Do ths by building a single (non-empty) vector of arguments and
13077 building the expression from those elements. */
13079 static tree
13081 tree in_decl)
13082 {
13091 {
13096 }
13105 }
13107 /* Walk through the pattern of a pack expansion, adding everything in
13108 local_specializations to a list. */
13110 class el_data
13111 {
13113 /* Set of variables declared within the pattern. */
13115 /* Set of AST nodes that have been visited by the traversal. */
13117 /* List of local_specializations used within the pattern. */
13118 tree extra;
13119 tsubst_flags_t complain;
13120 /* True iff we don't want to walk into unevaluated contexts. */
13122 /* The unevaluated contexts that we avoided walking. */
13127 };
13128 static tree
13130 {
13137 {
13141 }
13144 /* Remember local typedefs (85214). */
13148 {
13154 {
13157 decl2
13163 {
13166 }
13167 }
13168 }
13170 {
13171 /* Since we defer implicit capture, look in the parms and body. */
13177 }
13179 {
13181 /* Don't mess with variables declared within the pattern. */
13184 {
13185 /* Maybe pull out the PARM_DECL for a partial instantiation. */
13188 {
13194 }
13196 {
13197 /* Handle lambda capture here, since we aren't doing any
13198 substitution now, and so tsubst_copy won't call
13199 process_outer_var_ref. */
13203 {
13209 {
13210 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
13211 proxies. */
13213 {
13218 }
13220 }
13221 }
13222 }
13223 }
13227 }
13229 }
13230 static tree
13232 {
13234 /* Walk the pattern twice, ignoring unevaluated operands the first time
13235 around, so that if a local specialization appears in both an evaluated
13236 and unevaluated context we prefer to process it in the evaluated context
13237 (since e.g. process_outer_var_ref is a no-op inside an unevaluated
13238 context). */
13241 /* Now walk the unevaluated contexts we skipped the first time around. */
13244 {
13247 }
13249 }
13251 /* Extract any uses of local_specializations from PATTERN and add them to ARGS
13252 for use in PACK_EXPANSION_EXTRA_ARGS. */
13254 tree
13256 {
13257 /* Make a copy of the extra arguments so that they won't get changed
13258 out from under us. */
13264 }
13266 /* Apply any local specializations from PACK_EXPANSION_EXTRA_ARGS and add the
13267 normal template args to ARGS. */
13269 tree
13271 {
13273 {
13275 {
13276 /* The partial instantiation involved local declarations collected in
13277 extract_local_specs; map from the general template to our local
13278 context. */
13284 /* else inst is already a full instantiation of the pack. */
13286 }
13289 }
13291 {
13292 /* This can happen after dependent substitution into a
13293 requires-expr or a lambda that uses constexpr if. */
13296 }
13297 else
13300 }
13302 /* Substitute ARGS into T, which is an pack expansion
13303 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
13304 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
13305 (if only a partial substitution could be performed) or
13306 ERROR_MARK_NODE if there was an error. */
13307 tree
13309 tree in_decl)
13310 {
13311 tree pattern;
13315 tree result;
13322 /* Add in any args remembered from an earlier partial instantiation. */
13327 /* Determine the argument packs that will instantiate the parameter
13328 packs used in the expansion expression. While we're at it,
13329 compute the number of arguments to be expanded and make sure it
13330 is consistent. */
13333 {
13340 {
13345 in_decl),
13346 complain);
13347 else
13350 complain);
13351 }
13353 {
13355 {
13358 parm_pack);
13360 }
13363 }
13365 {
13366 /* We know we have correct local_specializations if this
13367 expansion is at function scope, or if we're dealing with a
13368 local parameter in a requires expression; for the latter,
13369 tsubst_requires_expr set it up appropriately. */
13372 else
13373 /* We can't rely on local_specializations for a parameter
13374 name used later in a function declaration (such as in a
13375 late-specified return type). Even if it exists, it might
13376 have the wrong value for a recursive call. */
13380 {
13381 /* This parameter pack was used in an unevaluated context. Just
13382 make a dummy decl, since it's only used for its type. */
13387 /* Partial instantiation of the parm_pack, we can't build
13388 up an argument pack yet. */
13390 else
13392 }
13394 /* This argument pack isn't fully instantiated yet. */
13396 }
13398 {
13402 }
13403 else
13404 {
13413 }
13420 /* This can only happen if we forget to expand an argument
13421 pack somewhere else. Just return an error, silently. */
13422 {
13426 }
13429 {
13433 /* Don't bother trying to do a partial substitution with
13434 incomplete packs; we'll try again after deduction. */
13441 {
13446 pattern);
13447 else
13449 pattern);
13451 }
13453 /* Keep track of the parameter packs and their corresponding
13454 argument packs. */
13457 }
13458 else
13459 {
13460 /* We can't substitute for this parameter pack. We use a flag as
13461 well as the missing_level counter because function parameter
13462 packs don't have a level. */
13465 }
13466 }
13468 /* If the expansion is just T..., return the matching argument pack, unless
13469 we need to call convert_from_reference on all the elements. This is an
13470 important optimization; see c++/68422. */
13473 {
13476 /* If the argument pack is a single pack expansion, pull it out. */
13481 /* Types need no adjustment, nor does sizeof..., and if we still have
13482 some pack expansion args we won't do anything yet. */
13487 /* Also optimize expression pack expansions if we can tell that the
13488 elements won't have reference type. */
13494 /* Otherwise use the normal path so we get convert_from_reference. */
13495 }
13497 /* We cannot expand this expansion expression, because we don't have
13498 all of the argument packs we need. */
13500 {
13501 /* We got some full packs, but we can't substitute them in until we
13502 have values for all the packs. So remember these until then. */
13508 }
13510 /* If NEED_LOCAL_SPECIALIZATIONS then we're in a late-specified return
13511 type, so create our own local specializations map; the current map is
13512 either NULL or (in the case of recursive unification) might have
13513 bindings that we don't want to use or alter. */
13518 {
13519 /* There were no real arguments, we're just replacing a parameter
13520 pack with another version of itself. Substitute into the
13521 pattern and return a PACK_EXPANSION_*. The caller will need to
13522 deal with that. */
13525 else
13531 {
13532 /* This is a fake auto... pack expansion created in add_capture with
13533 _PACKS that don't appear in the pattern. Copy one over. */
13540 }
13542 }
13546 /* For each argument in each argument pack, substitute into the
13547 pattern. */
13551 {
13553 i,
13555 in_decl);
13558 {
13561 }
13562 }
13564 /* Update ARGS to restore the substitution from parameter packs to
13565 their argument packs. */
13567 {
13574 else
13575 {
13583 /* Update the corresponding argument. */
13587 else
13589 }
13590 }
13592 /* If the dependent pack arguments were such that we end up with only a
13593 single pack expansion again, there's no need to keep it in a TREE_VEC. */
13599 }
13601 /* Make an argument pack out of the TREE_VEC VEC. */
13603 static tree
13605 {
13606 tree pack;
13610 else
13611 {
13614 }
13617 }
13619 /* Return an exact copy of template args T that can be modified
13620 independently. */
13622 static tree
13624 {
13632 {
13637 }
13643 }
13645 /* Substitute ARGS into the *_ARGUMENT_PACK orig_arg. */
13647 tree
13649 tree in_decl)
13650 {
13651 /* This flag is used only during deduction, and we don't expect to
13652 substitute such ARGUMENT_PACKs. */
13655 /* Substitute into each of the arguments. */
13664 /* If we're substituting into a generic ARGUMENT_PACK for a variadic
13665 template parameter, we might be able to avoid allocating a new
13666 ARGUMENT_PACK and reuse the corresponding ARGUMENT_PACK from ARGS
13667 if the substituted result is identical to it. */
13669 {
13676 {
13679 }
13680 }
13682 tree new_arg;
13684 {
13687 }
13688 else
13689 {
13692 }
13695 }
13697 /* Substitute ARGS into the vector or list of template arguments T. */
13699 tree
13701 {
13705 /* In "sizeof(X<I>)" we need to evaluate "I". */
13706 cp_evaluated ev;
13712 /* True iff the substituted result is identical to T. */
13716 {
13718 tree new_arg;
13725 {
13726 /* Substitute into an expansion expression. */
13730 /* Add to the expanded length adjustment the number of
13731 expanded arguments. We subtract one from this
13732 measurement, because the argument pack expression
13733 itself is already counted as 1 in
13734 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
13735 the argument pack is empty. */
13737 }
13740 else
13749 }
13756 /* If ARGS and T are both multi-level, the substituted result may be
13757 identical to ARGS. */
13762 /* If T appears to be a vector of generic template arguments, the
13763 substituted result may be identical to the corresponding level
13764 from ARGS. */
13766 {
13771 }
13773 /* If the substituted result is identical to MAYBE_REUSE, return
13774 it and avoid allocating a new TREE_VEC, as an optimization. */
13780 /* If T consists of only a pack expansion for which substitution yielded
13781 a TREE_VEC of the expanded elements, then reuse that TREE_VEC instead
13782 of effectively making a copy. */
13788 /* Make space for the expanded arguments coming from template
13789 argument packs. */
13791 /* T can contain TREE_VECs. That happens if T contains the
13792 arguments for a member template.
13793 In that case each TREE_VEC in T represents a level of template
13794 arguments, and T won't carry any non defaulted argument count.
13795 It will rather be the nested TREE_VECs that will carry one.
13796 In other words, T carries a non defaulted argument count only
13797 if it doesn't contain any nested TREE_VEC. */
13799 {
13803 }
13807 {
13812 {
13813 /* Now expand the template argument pack "in place". */
13816 }
13817 else
13818 {
13820 out++;
13821 }
13822 }
13826 }
13828 /* Substitute ARGS into one level PARMS of template parameters. */
13830 static tree
13832 {
13839 {
13847 }
13850 }
13852 /* Return the result of substituting ARGS into the template parameters
13853 given by PARMS. If there are m levels of ARGS and m + n levels of
13854 PARMS, then the result will contain n levels of PARMS. For
13855 example, if PARMS is `template <class T> template <class U>
13856 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
13857 result will be `template <int*, double, class V>'. */
13859 static tree
13861 {
13865 /* When substituting into a template, we must set
13866 PROCESSING_TEMPLATE_DECL as the template parameters may be
13867 dependent if they are based on one-another, and the dependency
13868 predicates are short-circuit outside of templates. */
13875 {
13884 }
13889 }
13891 /* Return the result of substituting ARGS into one template parameter
13892 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
13893 parameter and which TREE_PURPOSE is the default argument of the
13894 template parameter. */
13896 static tree
13898 {
13921 }
13923 /* Substitute in-place the TEMPLATE_PARM_CONSTRAINTS of each template
13924 parameter in PARMS for sake of declaration matching. */
13926 static void
13928 tsubst_flags_t complain)
13929 {
13932 {
13938 }
13940 }
13942 /* Substitute the ARGS into the indicated aggregate (or enumeration)
13943 type T. If T is not an aggregate or enumeration type, it is
13944 handled as if by tsubst. IN_DECL is as for tsubst. If
13945 ENTERING_SCOPE is nonzero, T is the context for a template which
13946 we are presently tsubst'ing. Return the substituted value. */
13948 static tree
13950 tree args,
13951 tsubst_flags_t complain,
13952 tree in_decl,
13954 {
13958 /* Handle typedefs via tsubst so that they get consistently reused. */
13960 {
13965 /* The effect of entering_scope is that for a dependent specialization
13966 A<T>, lookup_template_class prefers to return A's primary template
13967 type instead of the implicit instantiation. So when entering_scope,
13968 we mirror this behavior by inspecting TYPE_CANONICAL appropriately,
13969 taking advantage of the fact that lookup_template_class links the two
13970 types by setting TYPE_CANONICAL of the latter to the former. */
13978 }
13981 {
13989 }
13990 }
13992 /* The part of tsubst_aggr_type that's shared with the RECORD_, UNION_
13993 and ENUMERAL_TYPE cases of tsubst. */
13995 static tree
13997 tree args,
13998 tsubst_flags_t complain,
13999 tree in_decl,
14001 {
14003 {
14006 /* Figure out what arguments are appropriate for the
14007 type we are trying to find. For example, given:
14009 template <class T> struct S;
14010 template <class T, class U> void f(T, U) { S<U> su; }
14012 and supposing that we are instantiating f<int, double>,
14013 then our ARGS will be {int, double}, but, when looking up
14014 S we only want {double}. */
14023 }
14024 else
14025 /* This is not a template type, so there's nothing to do. */
14027 }
14029 /* Map from a FUNCTION_DECL to a vec of default argument instantiations,
14030 indexed in reverse order of the parameters. */
14034 /* Return a reference to the vec* of defarg insts for FN. */
14038 {
14042 tree_vec_map **slot
14045 {
14048 }
14050 }
14052 /* Substitute into the default argument ARG (a default argument for
14053 FN), which has the indicated TYPE. */
14055 tree
14057 tsubst_flags_t complain)
14058 {
14061 /* This can happen in invalid code. */
14065 /* Shortcut {}. */
14080 /* Remember the location of the pointer to the vec rather than the location
14081 of the particular element, in case the vec grows in tsubst_expr. */
14083 /* Index in reverse order to avoid allocating space for initial parameters
14084 that don't have default arguments. */
14091 /* This default argument came from a template. Instantiate the
14092 default argument here, not in tsubst. In the case of
14093 something like:
14095 template <class T>
14096 struct S {
14097 static T t();
14098 void f(T = t());
14099 };
14101 we must be careful to do name lookup in the scope of S<T>,
14102 rather than in the current class. */
14106 /* So in_immediate_context knows this is a default argument. */
14110 /* The default argument expression may cause implicitly defined
14111 member functions to be synthesized, which will result in garbage
14112 collection. We must treat this situation as if we were within
14113 the body of function so as to avoid collecting live data on the
14114 stack. */
14121 /* Make sure the default argument is reasonable. */
14138 }
14140 /* Substitute into all the default arguments for FN. */
14142 static void
14144 {
14145 tree arg;
14146 tree tmpl_args;
14150 /* If this function is not yet instantiated, we certainly don't need
14151 its default arguments. */
14154 /* Don't do this again for clones. */
14160 arg;
14166 complain);
14167 }
14169 /* Hash table mapping a FUNCTION_DECL to its dependent explicit-specifier. */
14172 /* Store a pair to EXPLICIT_SPECIFIER_MAP. */
14174 void
14176 {
14181 }
14183 /* Lookup an element in EXPLICIT_SPECIFIER_MAP. */
14185 tree
14187 {
14189 }
14191 /* Given T, a FUNCTION_TYPE or METHOD_TYPE, construct and return a corresponding
14192 FUNCTION_TYPE or METHOD_TYPE whose return type is RETURN_TYPE, argument types
14193 are ARG_TYPES, and exception specification is RAISES, and otherwise is
14194 identical to T. */
14196 static tree
14199 {
14202 tree new_type;
14204 {
14207 }
14208 else
14209 {
14211 /* Don't pick up extra function qualifiers from the basetype. */
14214 {
14215 /* [temp.deduct]
14217 Type deduction may fail for any of the following
14218 reasons:
14220 -- Attempting to create "pointer to member of T" when T
14221 is not a class type. */
14224 r);
14226 }
14230 }
14236 }
14238 /* Check if the function type of DECL, a FUNCTION_DECL, agrees with the type of
14239 each of its formal parameters. If there is a disagreement then rebuild
14240 DECL's function type according to its formal parameter types, as part of a
14241 resolution for Core issues 1001/1322. */
14243 static void
14245 {
14248 {
14251 {
14255 {
14258 }
14262 }
14263 }
14274 {
14279 }
14281 {
14291 }
14299 }
14301 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
14303 static tree
14305 tree lambda_fntype)
14306 {
14311 /* Nobody should be tsubst'ing into non-template functions. */
14316 {
14319 }
14321 {
14322 /* If T is not dependent, just return it. */
14327 /* A non-templated friend doesn't get DECL_TEMPLATE_INFO. */
14331 /* Calculate the most general template of which R is a
14332 specialization. */
14335 /* We're substituting a lambda function under tsubst_lambda_expr but not
14336 directly from it; find the matching function we're already inside.
14337 But don't do this if T is a generic lambda with a single level of
14338 template parms, as in that case we're doing a normal instantiation. */
14344 /* Calculate the complete set of arguments used to
14345 specialize R. */
14347 (DECL_TEMPLATE_RESULT
14353 /* Check to see if we already have this specialization. */
14355 {
14358 /* The spec for these args might be a partial instantiation of the
14359 template, but here what we want is the FUNCTION_DECL. */
14361 }
14362 }
14363 else
14364 {
14365 /* This special case arises when we have something like this:
14367 template <class T> struct S {
14368 friend void f<int>(int, double);
14369 };
14371 Here, the DECL_TI_TEMPLATE for the friend declaration
14372 will be an IDENTIFIER_NODE. We are being called from
14373 tsubst_friend_function, and we want only to create a
14374 new decl (R) with appropriate types so that we can call
14375 determine_specialization. */
14376 friend_case:
14379 }
14386 /* If this is a static lambda, remove the 'this' pointer added in
14387 tsubst_lambda_expr now that we know the closure type. */
14401 /* If we hit excessive deduction depth, the type is bogus even if
14402 it isn't error_mark_node, so don't build a decl. */
14406 /* We do NOT check for matching decls pushed separately at this
14407 point, as they may not represent instantiations of this
14408 template, and in any case are considered separate under the
14409 discrete model. */
14413 /* Clear out the mangled name and RTL for the instantiation. */
14416 /* Leave DECL_INITIAL set on deleted instantiations. */
14422 /* Handle explicit(dependent-expr). */
14424 {
14432 else
14433 {
14436 }
14437 }
14439 /* OpenMP UDRs have the only argument a reference to the declared
14440 type. We want to diagnose if the declared type is a reference,
14441 which is invalid, but as references to references are usually
14442 quietly merged, diagnose it here. */
14444 {
14445 tree argtype
14450 "reference type %qT in "
14454 argtype);
14455 }
14458 /* Type-conversion operator. Reconstruct the name, in
14459 case it's the name of one of the template's parameters. */
14469 {
14474 }
14483 /* If this is an instantiation of a function with internal
14484 linkage, we already know what object file linkage will be
14485 assigned to the instantiation. */
14494 /* We'll re-clone as appropriate in instantiate_template. */
14497 /* If we aren't complaining now, return on error before we register
14498 the specialization so that we'll complain eventually. */
14504 /* Associate the constraints directly with the instantiation. We
14505 don't substitute through the constraints; that's only done when
14506 they are checked. */
14519 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
14520 this in the special friend case mentioned above where
14521 GEN_TMPL is NULL. */
14523 {
14528 tree new_r
14531 /* We instantiated this while substituting into
14532 the type earlier (template/friend54.C). */
14535 /* We're not supposed to instantiate default arguments
14536 until they are called, for a template. But, for a
14537 declaration like:
14539 template <class T> void f ()
14540 { extern void g(int i = T()); }
14542 we should do the substitution when the template is
14543 instantiated. We handle the member function case in
14544 instantiate_class_template since the default arguments
14545 might refer to other members of the class. */
14550 }
14552 {
14555 }
14556 else
14559 /* Copy the list of befriending classes. */
14563 {
14567 }
14570 {
14574 /* If this is an instantiation of a member template, clone it.
14575 If it isn't, that'll be handled by
14576 clone_constructors_and_destructors. */
14579 }
14585 /* Possibly limit visibility based on template args. */
14588 {
14592 }
14604 }
14606 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
14608 static tree
14611 {
14612 /* We can get here when processing a member function template,
14613 member class template, or template template parameter. */
14616 tree spec;
14617 tree tmpl_args;
14618 tree full_args;
14619 tree r;
14623 {
14624 /* Template template parameter is treated here. */
14628 /* If we get a real template back, return it. This can happen in
14629 the context of most_specialized_partial_spec. */
14632 else
14633 /* The new TEMPLATE_DECL was built in
14634 reduce_template_parm_level. */
14637 }
14640 {
14641 /* We might already have an instance of this template.
14642 The ARGS are for the surrounding class type, so the
14643 full args contain the tsubst'd args for the context,
14644 plus the innermost args from the template decl. */
14648 /* Because this is a template, the arguments will still be
14649 dependent, even after substitution. If
14650 PROCESSING_TEMPLATE_DECL is not set, the dependency
14651 predicates will short-circuit. */
14659 /* If this is a default template template argument,
14660 tsubst might not have changed anything. */
14667 {
14669 /* Type partial instantiations are stored as the type by
14670 lookup_template_class_1, not here as the template. */
14673 }
14674 }
14676 /* Make a new template decl. It will be similar to the
14677 original, but will record the current template arguments.
14678 We also create a new function declaration, which is just
14679 like the old one, but points to this new template, rather
14680 than the old one. */
14685 // Build new template info linking to the original template decl.
14687 {
14690 }
14691 else
14694 /* The template parameters for this new template are all the
14695 template parameters for the old template, except the
14696 outermost level of parameters. */
14699 = current_template_parms
14700 = (lambda_tparms
14701 ? lambda_tparms
14703 complain));
14710 else
14711 {
14713 {
14716 }
14720 else
14722 }
14728 {
14729 /* For a partial specialization, we need to keep pointing to
14730 the primary template. */
14732 {
14735 }
14739 }
14741 {
14744 }
14745 else
14746 {
14749 }
14756 {
14757 /* Propagate module information from the decl. */
14760 /* If this is a constrained template, the above tsubst of
14761 inner can find the unconstrained template, which may have
14762 come from an import. This is ok, because we don't
14763 register this instantiation (see below). */
14765 || (TEMPLATE_PARMS_CONSTRAINTS
14767 }
14776 /* Record this non-type partial instantiation. */
14782 }
14784 /* True if FN is the op() for a lambda in an uninstantiated template. */
14786 bool
14788 {
14793 }
14795 /* True if FN is the substitution (via tsubst_lambda_expr) of a function for
14796 which the above is true. */
14798 bool
14800 {
14806 }
14808 /* Return the LAMBDA_EXPR from which T was ultimately regenerated.
14809 If T is not a regenerated LAMBDA_EXPR, return T. */
14811 tree
14813 {
14817 }
14819 /* Return the set of template arguments used to regenerate the lambda T
14820 from its most general lambda. */
14822 tree
14824 {
14830 else
14832 }
14834 /* We're instantiating a variable from template function TCTX. Return the
14835 corresponding current enclosing scope. We can match them up using
14836 DECL_SOURCE_LOCATION because lambdas only ever have one source location, and
14837 the DECL_SOURCE_LOCATION for a function instantiation is updated to match
14838 the template definition in regenerate_decl_from_template. */
14840 static tree
14842 {
14845 /* We shouldn't ever need to do this for other artificial functions. */
14852 }
14854 /* Substitute the ARGS into the T, which is a _DECL. Return the
14855 result of the substitution. Issue error and warning messages under
14856 control of COMPLAIN. */
14858 static tree
14860 {
14861 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
14862 location_t saved_loc;
14867 /* Set the filename and linenumber to improve error-reporting. */
14872 {
14884 {
14892 {
14893 /* If there is a local specialization that isn't a
14894 parameter pack, it means that we're doing a "simple"
14895 substitution from inside tsubst_pack_expansion. Just
14896 return the local specialization (which will be a single
14897 parm). */
14904 /* Expand the TYPE_PACK_EXPANSION that provides the types for
14905 the parameters in this function parameter pack. */
14909 {
14912 /* Zero-length parameter packs are boring. Just substitute
14913 into the chain. */
14917 }
14918 else
14919 {
14920 /* All we did was update the type. Make a note of that. */
14923 }
14924 }
14926 /* Loop through all of the parameters we'll build. When T is
14927 a function parameter pack, LEN is the number of expanded
14928 types in EXPANDED_TYPES; otherwise, LEN is 1. */
14931 {
14938 /* We're on the Ith parameter of the function parameter
14939 pack. */
14940 {
14941 /* Get the Ith type. */
14944 /* Rename the parameter to include the index. */
14947 }
14949 /* We're dealing with a normal parameter. */
14957 {
14960 else
14963 }
14974 /* Keep track of the first new parameter we
14975 generate. That's what will be returned to the
14976 caller. */
14980 /* Build a proper chain of parameters when substituting
14981 into a function parameter pack. */
14984 }
14986 /* If cp_unevaluated_operand is set, we're just looking for a
14987 single dummy parameter, so don't keep going. */
14992 /* FIRST_R contains the start of the chain we've built. */
14994 }
14998 {
15005 {
15006 /* This field is a lambda capture pack. Return a TREE_VEC of
15007 the expanded fields to instantiate_class_template_1. */
15011 {
15014 }
15015 else
15016 {
15017 /* All we did was update the type. Make a note of that. */
15020 }
15021 }
15024 {
15027 {
15031 }
15041 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
15042 number of bits. */
15047 {
15048 /* Set up DECL_TEMPLATE_INFO so that we can get at the
15049 NSDMI in perform_member_init. Still set DECL_INITIAL
15050 so that we know there is one. */
15055 }
15056 /* We don't have to set DECL_CONTEXT here; it is set by
15057 finish_member_declaration. */
15066 }
15070 }
15074 /* We reach here only for member using decls. We also need to check
15075 uses_template_parms because DECL_DEPENDENT_P is not set for a
15076 using-declaration that designates a member of the current
15077 instantiation (c++/53549). */
15080 {
15081 /* True iff this using-decl was written as a pack expansion
15082 (and a pack appeared in its scope or name). If a pack
15083 appeared in both, we expand the packs separately and
15084 manually merge them. */
15089 {
15092 in_decl);
15094 }
15095 else
15101 {
15105 {
15108 }
15112 }
15113 else
15121 {
15123 {
15128 }
15130 }
15138 {
15147 {
15150 }
15154 }
15158 }
15159 else
15160 {
15163 }
15168 {
15179 {
15180 /* If this is the canonical decl, we don't have to
15181 mess with instantiations, and often we can't (for
15182 typename, template type parms and such). Note that
15183 TYPE_NAME is not correct for the above test if
15184 we've copied the type for a typedef. */
15190 }
15192 /* Check to see if we already have the specialization we
15193 need. */
15199 {
15202 {
15204 complain,
15207 /* The context and type of an injected-class-name are
15208 the same, so we don't need to substitute both. */
15210 /* If CTX is unchanged, then T is in fact the
15211 specialization we want. That situation occurs when
15212 referencing a static data member within in its own
15213 class. We can use pointer equality, rather than
15214 same_type_p, because DECL_CONTEXT is always
15215 canonical... */
15217 /* ... unless T is a member template; in which
15218 case our caller can be willing to create a
15219 specialization of that template represented
15220 by T. */
15224 }
15227 {
15234 /* We're fully specializing a template declaration, so
15235 we need to coerce the innermost arguments corresponding to
15236 the template. */
15237 argvec = (coerce_template_parms
15244 }
15245 }
15246 else
15247 {
15249 /* Subsequent calls to pushdecl will fill this in. */
15251 /* A local variable. */
15253 /* Unless this is a reference to a static variable from an
15254 enclosing function, in which case we need to fill it in now. */
15256 {
15260 }
15262 }
15263 /* If we already have the specialization we need, there is
15264 nothing more to do. */
15266 {
15269 }
15271 /* Create a new node for the specialization we need. */
15273 {
15276 else
15286 /* Substituting the type might have recursively instantiated this
15287 same alias (c++/86171). */
15290 {
15293 }
15294 }
15297 {
15303 {
15304 /* It may seem that this case cannot occur, since:
15306 typedef void f();
15307 void g() { f x; }
15309 declares a function, not a variable. However:
15311 typedef void f();
15312 template <typename T> void g() { T t; }
15313 template void g<f>();
15315 is an attempt to declare a variable with function
15316 type. */
15318 /* R is not yet sufficiently initialized, so we
15319 just use its name. */
15322 }
15324 /* Wait until cp_finish_decl to set this again, to handle
15325 circular dependency (template/instantiate6.C). */
15330 {
15332 /* If the DECL_VALUE_EXPR is converted to the declared type,
15333 preserve the identity so that gimplify_type_sizes works. */
15339 {
15342 }
15351 else
15355 }
15359 }
15365 /* Clear out the mangled name and RTL for the instantiation. */
15371 /* The initializer must not be expanded until it is required;
15372 see [temp.inst]. */
15376 {
15382 /* Possibly limit visibility based on template args. */
15385 {
15389 }
15391 }
15394 {
15395 /* A static data member declaration is always marked
15396 external when it is declared in-class, even if an
15397 initializer is present. We mimic the non-template
15398 processing here. */
15407 }
15408 else
15409 {
15414 }
15423 /* Preserve a typedef that names a type. */
15425 {
15429 /* common_handle_aligned_attribute doesn't apply the alignment
15430 to DECL_ORIGINAL_TYPE. */
15434 }
15437 }
15442 }
15443 #undef RETURN
15445 out:
15446 /* Restore the file and line information. */
15450 }
15452 /* Substitute into the complete parameter type list PARMS. */
15454 tree
15456 tree args,
15457 tsubst_flags_t complain,
15458 tree in_decl)
15459 {
15461 }
15463 /* Substitute into the ARG_TYPES of a function type.
15464 If END is a TREE_CHAIN, leave it and any following types
15465 un-substituted. */
15467 static tree
15469 tree args,
15470 tree end,
15471 tsubst_flags_t complain,
15472 tree in_decl)
15473 {
15482 {
15483 /* For a pack expansion, perform substitution on the
15484 entire expression. Later on, we'll handle the arguments
15485 one-by-one. */
15490 /* So that we'll spin through the parameters, one by one. */
15492 else
15493 {
15494 /* We only partially substituted into the parameter
15495 pack. Our type is TYPE_PACK_EXPANSION. */
15498 }
15499 }
15500 else
15503 /* Check if a substituted type is erroneous before substituting into
15504 the rest of the chain. */
15506 {
15513 {
15515 {
15519 }
15521 }
15522 }
15524 /* We do not substitute into default arguments here. The standard
15525 mandates that they be instantiated only when needed, which is
15526 done in build_over_call. */
15529 /* Except that we do substitute default arguments under tsubst_lambda_expr,
15530 since the new op() won't have any associated template arguments for us
15531 to refer to later. */
15543 {
15547 /* Do array-to-pointer, function-to-pointer conversion, and ignore
15548 top-level qualifiers as required. */
15552 {
15553 /* We've instantiated a template before its default arguments
15554 have been parsed. This can happen for a nested template
15555 class, and is not an error unless we require the default
15556 argument in a call of this function. */
15557 remaining_arg_types
15560 remaining_arg_types);
15561 }
15562 else
15563 remaining_arg_types
15565 }
15568 }
15570 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
15571 *not* handle the exception-specification for FNTYPE, because the
15572 initial substitution of explicitly provided template parameters
15573 during argument deduction forbids substitution into the
15574 exception-specification:
15576 [temp.deduct]
15578 All references in the function type of the function template to the
15579 corresponding template parameters are replaced by the specified tem-
15580 plate argument values. If a substitution in a template parameter or
15581 in the function type of the function template results in an invalid
15582 type, type deduction fails. [Note: The equivalent substitution in
15583 exception specifications is done only when the function is instanti-
15584 ated, at which point a program is ill-formed if the substitution
15585 results in an invalid type.] */
15587 static tree
15589 tree args,
15590 tsubst_flags_t complain,
15591 tree in_decl)
15592 {
15593 tree return_type;
15596 /* The TYPE_CONTEXT is not used for function/method types. */
15599 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
15600 failure. */
15604 {
15605 /* Substitute the argument types. */
15617 {
15618 /* DR 1207: 'this' is in scope in the trailing return type. */
15620 }
15622 /* Substitute the return type. */
15626 {
15629 }
15630 }
15631 else
15632 /* Substitute the return type. */
15637 /* DR 486 clarifies that creation of a function type with an
15638 invalid return type is a deduction failure. */
15641 {
15643 {
15646 else
15648 }
15650 }
15653 {
15654 /* Substitute the argument types. */
15659 }
15661 /* Construct a new type node and return it. */
15664 }
15666 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
15667 ARGS into that specification, and return the substituted
15668 specification. If there is no specification, return NULL_TREE. */
15670 static tree
15672 tree args,
15673 tsubst_flags_t complain,
15674 tree in_decl,
15676 {
15677 tree specs;
15678 tree new_specs;
15683 {
15684 /* A noexcept-specifier. */
15689 {
15690 /* Defer instantiation of noexcept-specifiers to avoid
15691 excessive instantiations (c++/49107). */
15694 {
15695 /* We already partially instantiated this member template,
15696 so combine the new args with the old. */
15701 }
15702 else
15703 {
15706 }
15707 }
15708 else
15709 {
15711 {
15713 args);
15715 }
15717 }
15719 /* We've instantiated a template before a noexcept-specifier
15720 contained therein has been parsed. This can happen for
15721 a nested template class:
15723 struct S {
15724 template<typename> struct B { B() noexcept(...); };
15725 struct A : B<int> { ... use B() ... };
15726 };
15728 where completing B<int> will trigger instantiating the
15729 noexcept, even though we only parse it at the end of S. */
15731 {
15734 }
15735 }
15737 {
15740 else
15742 {
15743 tree spec;
15748 {
15749 /* Expand the pack expansion type. */
15752 in_decl);
15758 else
15759 {
15760 /* We're substituting into a member template, so
15761 we got a TYPE_PACK_EXPANSION back. Add that
15762 expansion and move on. */
15766 expanded_specs,
15767 complain);
15770 }
15771 }
15774 {
15777 else
15782 complain);
15783 }
15786 }
15787 }
15789 }
15791 /* Substitute through a TREE_LIST of types or expressions, handling pack
15792 expansions. */
15794 tree
15796 {
15803 ;
15805 {
15809 }
15812 else
15820 ;
15822 {
15826 }
15829 else
15836 ;
15841 else
15852 /* Determine the number of arguments. */
15854 {
15857 }
15860 else
15864 {
15872 else
15874 }
15877 }
15879 /* Take the tree structure T and replace template parameters used
15880 therein with the argument vector ARGS. IN_DECL is an associated
15881 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
15882 Issue error and warning messages under control of COMPLAIN. Note
15883 that we must be relatively non-tolerant of extensions here, in
15884 order to preserve conformance; if we allow substitutions that
15885 should not be allowed, we may allow argument deductions that should
15886 not succeed, and therefore report ambiguous overload situations
15887 where there are none. In theory, we could allow the substitution,
15888 but indicate that it should have failed, and allow our caller to
15889 make sure that the right thing happens, but we don't try to do this
15890 yet.
15892 This function is used for dealing with types, decls and the like;
15893 for expressions, use tsubst_expr or tsubst_copy. */
15895 tree
15897 {
15932 /* Reuse typedefs. We need to do this to handle dependent attributes,
15933 such as attribute aligned. */
15936 {
15940 {
15941 /* DECL represents an alias template and we want to
15942 instantiate it. */
15946 }
15950 {
15954 }
15959 else
15960 /* The typedef is from a non-template context. */
15964 {
15966 r = cp_build_qualified_type
15970 }
15971 else
15972 {
15973 /* We don't have an instantiation yet, so drop the typedef. */
15978 }
15979 }
15996 {
16000 /* Fall through. */
16026 {
16031 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
16032 needed. */
16038 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
16039 with TREE_SIDE_EFFECTS that indicates this is not an integral
16040 constant expression. */
16043 {
16046 }
16049 }
16053 {
16061 else
16063 }
16064 /* Fall through. */
16068 {
16082 {
16085 /* See through ARGUMENT_PACK_SELECT arguments. */
16088 }
16093 {
16095 /* If ARG is an argument pack, we don't actually want to
16096 perform a substitution here, because substitutions
16097 for argument packs are only done
16098 element-by-element. We can get to this point when
16099 substituting the type of a non-type template
16100 parameter pack, when that type actually contains
16101 template parameter packs from an outer template, e.g.,
16103 template<typename... Types> struct A {
16104 template<Types... Values> struct B { };
16105 }; */
16109 {
16112 /* When building concept checks for the purpose of
16113 deducing placeholders, we can end up with wildcards
16114 where types are expected. Adjust this to the deduced
16115 value. */
16123 return cp_build_qualified_type
16125 }
16127 {
16128 /* We are processing a type constructed from a
16129 template template parameter. */
16140 /* Consider this code:
16142 template <template <class> class Template>
16143 struct Internal {
16144 template <class Arg> using Bind = Template<Arg>;
16145 };
16147 template <template <class> class Template, class Arg>
16148 using Instantiate = Template<Arg>; //#0
16150 template <template <class> class Template,
16151 class Argument>
16152 using Bind =
16153 Instantiate<Internal<Template>::template Bind,
16154 Argument>; //#1
16156 When #1 is parsed, the
16157 BOUND_TEMPLATE_TEMPLATE_PARM representing the
16158 parameter `Template' in #0 matches the
16159 UNBOUND_CLASS_TEMPLATE representing the argument
16160 `Internal<Template>::template Bind'; We then want
16161 to assemble the type `Bind<Argument>' that can't
16162 be fully created right now, because
16163 `Internal<Template>' not being complete, the Bind
16164 template cannot be looked up in that context. So
16165 we need to "store" `Bind<Argument>' for later
16166 when the context of Bind becomes complete. Let's
16167 store that in a TYPENAME_TYPE. */
16171 argvec),
16172 typename_type,
16173 complain);
16175 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
16176 are resolving nested-types in the signature of a
16177 member function templates. Otherwise ARG is a
16178 TEMPLATE_DECL and is the real template to be
16179 instantiated. */
16187 complain);
16188 return cp_build_qualified_type
16190 }
16193 else
16194 /* TEMPLATE_PARM_INDEX. */
16196 }
16199 /* This can happen during the attempted tsubst'ing in
16200 unify. This means that we don't yet have any information
16201 about the template parameter in question. */
16204 /* Early in template argument deduction substitution, we don't
16205 want to reduce the level of 'auto', or it will be confused
16206 with a normal template parm in subsequent deduction.
16207 Similarly, don't reduce the level of template parameters to
16208 avoid mismatches when deducing their types. */
16212 /* If we get here, we must have been looking at a parm for a
16213 more deeply nested template. Make a new version of this
16214 template parameter, but with a lower level. */
16217 {
16222 {
16225 }
16231 /* Cache lowering a type parameter or a simple template
16232 template parameter. */
16236 {
16248 /* Propagate constraints on placeholders since they are
16249 only instantiated during satisfaction. */
16254 else
16256 }
16264 {
16266 /* We might need to substitute into the types of non-type
16267 template parameters. This also lowers the level of
16268 the ttp appropriately. */
16281 }
16284 /* OK, now substitute the type of the non-type parameter. We
16285 couldn't do it earlier because it might be an auto parameter,
16286 and we wouldn't need to if we had an argument. */
16295 }
16298 }
16304 /* We should never be tsubsting a binfo. */
16308 /* A vector of template arguments. */
16314 {
16318 /* [temp.deduct]
16320 Type deduction may fail for any of the following
16321 reasons:
16323 -- Attempting to create a pointer to reference type.
16324 -- Attempting to create a reference to a reference type or
16325 a reference to void.
16327 Core issue 106 says that creating a reference to a reference
16328 during instantiation is no longer a cause for failure. We
16329 only enforce this check in strict C++98 mode. */
16333 {
16336 /* We keep track of the last time we issued this error
16337 message to avoid spewing a ton of messages during a
16338 single bad template instantiation. */
16341 {
16346 else
16349 }
16352 }
16356 {
16358 {
16361 type);
16362 else
16364 type);
16365 }
16367 }
16369 {
16373 }
16375 /* In C++0x, during template argument substitution, when there is an
16376 attempt to create a reference to a reference type, reference
16377 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
16379 "If a template-argument for a template-parameter T names a type
16380 that is a reference to a type A, an attempt to create the type
16381 'lvalue reference to cv T' creates the type 'lvalue reference to
16382 A,' while an attempt to create the type type rvalue reference to
16383 cv T' creates the type T"
16384 */
16385 r = cp_build_reference_type
16388 else
16393 /* Will this ever be needed for TYPE_..._TO values? */
16397 }
16399 {
16402 {
16403 /* [temp.deduct]
16405 Type deduction may fail for any of the following
16406 reasons:
16408 -- Attempting to create "pointer to member of T" when T
16409 is not a class type. */
16413 }
16415 {
16419 }
16421 {
16425 }
16428 {
16429 /* The type of the implicit object parameter gets its
16430 cv-qualifiers from the FUNCTION_TYPE. */
16431 tree memptr;
16432 tree method_type
16437 complain);
16438 }
16439 else
16442 complain);
16443 }
16446 {
16447 tree fntype;
16448 tree specs;
16453 /* Substitute the exception specification. */
16461 }
16463 {
16468 /* As an optimization, we avoid regenerating the array type if
16469 it will obviously be the same as T. */
16473 /* These checks should match the ones in create_array_type_for_decl.
16475 [temp.deduct]
16477 The deduction may fail for any of the following reasons:
16479 -- Attempting to create an array with an element type that
16480 is void, a function type, or a reference type, or [DR337]
16481 an abstract class type. */
16487 {
16491 }
16504 {
16507 }
16510 }
16513 {
16516 {
16519 in_decl);
16524 {
16529 }
16531 }
16532 else
16545 {
16549 }
16551 {
16552 /* Normally, make_typename_type does not require that the CTX
16553 have complete type in order to allow things like:
16555 template <class T> struct S { typename S<T>::X Y; };
16557 But, such constructs have already been resolved by this
16558 point, so here CTX really should have complete type, unless
16559 it's a partial instantiation. */
16562 }
16564 /* FIXME: TYPENAME_IS_CLASS_P conflates 'class' vs 'struct' vs 'union'
16565 tags. TYPENAME_TYPE should probably remember the exact tag that
16566 was written. */
16567 enum tag_types tag_type
16577 {
16580 }
16583 {
16585 {
16589 else
16591 }
16593 {
16597 else
16599 }
16600 }
16602 return cp_build_qualified_type
16604 }
16607 {
16619 }
16622 {
16623 tree type;
16637 complain);
16638 }
16641 {
16642 tree type;
16659 else
16660 {
16664 /* In a template ~id could be either a complement expression
16665 or an unqualified-id naming a destructor; if instantiating
16666 it produces an expression, it's not an id-expression or
16667 member access. */
16670 }
16675 }
16678 {
16682 else
16689 }
16708 /* We should use one of the expression tsubsts for these codes. */
16714 }
16715 }
16717 /* Convenience wrapper over tsubst for substituting into the LHS
16718 of the :: scope resolution operator. */
16720 static tree
16722 {
16725 }
16727 /* OLDFNS is a lookup set of member functions from some class template, and
16728 NEWFNS is a lookup set of member functions from NEWTYPE, a specialization
16729 of that class template. Return the subset of NEWFNS which are
16730 specializations of a function from OLDFNS. */
16732 static tree
16734 {
16735 /* Record all member functions from the old lookup set OLDFNS into
16736 VISIBLE_SET. */
16740 {
16742 {
16743 /* Imprecisely handle dependent using-decl by keeping all members
16744 in the new lookup set that are defined in a base class, i.e.
16745 members that could plausibly have been introduced by this
16746 dependent using-decl.
16747 FIXME: Track which members are introduced by a dependent
16748 using-decl precisely, perhaps by performing another lookup
16749 from the substituted USING_DECL_SCOPE. */
16752 }
16753 else
16755 }
16757 /* Returns true iff (a less specialized version of) FN appeared in
16758 the old lookup set OLDFNS. */
16761 /* FN is a member function from a base class, introduced via a
16762 using-decl; if it might have been introduced by a dependent
16763 using-decl then just conservatively keep it, otherwise look
16764 in the old lookup set for FN exactly. */
16767 /* FN is a member function template from the current class;
16768 look in the old lookup set for the TEMPLATE_DECL from which
16769 it was specialized. */
16771 else
16772 /* FN is a non-template member function from the current class;
16773 look in the old lookup set for the FUNCTION_DECL from which
16774 it was specialized. */
16777 };
16782 {
16785 }
16789 /* Filter out from NEWFNS the member functions that weren't
16790 previously visible according to OLDFNS. */
16795 {
16797 filtered_size++;
16798 }
16804 }
16806 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
16807 expression on the left-hand side of the "." or "->" operator. We
16808 only do the lookup if we had a dependent BASELINK. Otherwise we
16809 adjust it onto the instantiated heirarchy. */
16811 static tree
16814 {
16826 {
16833 }
16841 {
16846 /* See maybe_dependent_member_ref. */
16848 {
16851 template_args);
16854 }
16857 /* Treat as-if non-dependent below. */
16862 complain);
16864 {
16865 /* Filter out from the new lookup set those functions which didn't
16866 appear in the original lookup set (in a less specialized form).
16867 This is needed to preserve the consistency of member lookup
16868 performed in an incomplete-class context, within which
16869 later-declared members ought to remain invisible. */
16872 binfo_type);
16874 }
16877 {
16883 }
16886 }
16887 else
16888 {
16889 /* We're going to overwrite pieces below, make a duplicate. */
16893 {
16894 /* The decl we found was from non-dependent scope, but we still need
16895 to update the binfos for the instantiated qualifying_scope. */
16899 }
16900 }
16902 /* If lookup found a single function, mark it as used at this point.
16903 (If lookup found multiple functions the one selected later by
16904 overload resolution will be marked as used at that point.) */
16906 {
16912 /* We might have instantiated an auto function. */
16914 }
16917 {
16918 /* Add back the template arguments, if present. */
16923 /* Update the conversion operator type. */
16925 }
16931 {
16933 qualifying_scope,
16934 object_type);
16936 /* We need to call adjust_result_of_qualified_name_lookup in case the
16937 destructor names a base class, but we unset BASELINK_QUALIFIED_P
16938 so that we still get virtual function binding. */
16940 }
16943 }
16945 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
16946 true if the qualified-id will be a postfix-expression in-and-of
16947 itself; false if more of the postfix-expression follows the
16948 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
16949 of "&". */
16951 static tree
16955 {
16956 tree expr;
16957 tree scope;
16958 tree name;
16960 tree template_args;
16965 /* Figure out what name to look up. */
16968 {
16977 }
16978 else
16979 {
16982 }
16984 /* Substitute into the qualifying scope. When there are no ARGS, we
16985 are just trying to simplify a non-dependent expression. In that
16986 case the qualifying scope may be dependent, and, in any case,
16987 substituting will not help. */
16990 {
16993 }
16994 else
16998 {
17000 /* We built one in tsubst_baselink. */
17002 else
17003 {
17006 template_args);
17008 QUALIFIED_NAME_IS_TEMPLATE
17010 }
17013 }
17016 {
17018 {
17019 /* A BIT_NOT_EXPR is used to represent a destructor. */
17021 {
17025 }
17026 else
17029 }
17030 else
17034 {
17036 {
17040 }
17042 }
17043 }
17046 {
17050 /* Remember that there was a reference to this entity. */
17053 }
17056 {
17062 }
17065 {
17066 /* We may be repeating a check already done during parsing, but
17067 if it was well-formed and passed then, it will pass again
17068 now, and if it didn't, we wouldn't have got here. The case
17069 we want to catch is when we couldn't tell then, and can now,
17070 namely when templ prior to substitution was an
17071 identifier. */
17077 complain);
17078 else
17080 }
17086 {
17087 expr = (adjust_result_of_qualified_name_lookup
17089 expr = (finish_qualified_id_expr
17093 }
17095 /* Expressions do not generally have reference type. */
17097 /* However, if we're about to form a pointer-to-member, we just
17098 want the referenced member referenced. */
17108 }
17110 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
17111 initializer, DECL is the substituted VAR_DECL. Other arguments are as
17112 for tsubst. */
17114 static tree
17117 {
17126 {
17128 {
17130 {
17135 }
17136 }
17138 {
17139 /* If we had an initializer but it
17140 instantiated to nothing,
17141 value-initialize the object. This will
17142 only occur when the initializer was a
17143 pack expansion where the parameter packs
17144 used in that expansion were of length
17145 zero. */
17151 }
17152 }
17155 }
17157 /* If T is a reference to a dependent member of the current instantiation C and
17158 we are trying to refer to that member in a partial instantiation of C,
17159 return a SCOPE_REF; otherwise, return NULL_TREE.
17161 This can happen when forming a C++17 deduction guide, as in PR96199. */
17163 static tree
17165 tree in_decl)
17166 {
17183 {
17192 complain);
17193 }
17198 {
17204 }
17207 {
17210 /* The TYPE_DECL for a typename has DECL_CONTEXT of the typename
17211 scope, but it doesn't need to be rewritten again. */
17215 }
17219 else
17222 }
17224 /* Like tsubst, but deals with expressions. This function just replaces
17225 template parms; to finish processing the resultant expression, use
17226 tsubst_copy_and_build or tsubst_expr. */
17228 static tree
17230 {
17232 tree r;
17246 {
17251 {
17252 /* We get here for a use of 'this' in an NSDMI. */
17256 /* This can happen for a parameter name used later in a function
17257 declaration (such as in a late-specified return type). Just
17258 make a dummy decl, since it's only used for its type. */
17261 /* Give it the template pattern as its context; its true context
17262 hasn't been instantiated yet and this is good enough for
17263 mangling. */
17265 }
17274 {
17275 tree enum_type;
17276 tree v;
17283 /* Unfortunately, we cannot just call lookup_name here.
17284 Consider:
17286 template <int I> int f() {
17287 enum E { a = I };
17288 struct S { void g() { E e = a; } };
17289 };
17291 When we instantiate f<7>::S::g(), say, lookup_name is not
17292 clever enough to find f<7>::a. */
17293 enum_type
17303 /* We didn't find the name. That should never happen; if
17304 name-lookup found it during preliminary parsing, we
17305 should find it again here during instantiation. */
17307 }
17312 {
17313 tree ctx;
17318 {
17321 {
17325 }
17327 }
17328 }
17337 {
17338 /* Local specialization will usually have been created when
17339 we instantiated the DECL_EXPR_DECL. */
17342 {
17343 /* We're in a generic lambda referencing a local extern
17344 from an outer block-scope of a non-template. */
17347 }
17348 }
17351 {
17354 {
17355 /* First try name lookup to find the instantiation. */
17358 {
17360 {
17361 /* During error-recovery we may find a non-variable,
17362 even an OVERLOAD: just bail out and avoid ICEs and
17363 duplicate diagnostics (c++/62207). */
17366 }
17368 {
17369 /* Make sure the one we found is the one we want. */
17373 }
17374 }
17378 else
17379 {
17380 /* This can happen for a variable used in a
17381 late-specified return type of a local lambda, or for a
17382 local static or constant. Building a new VAR_DECL
17383 should be OK in all those cases. */
17386 /* Avoid infinite recursion (79640). */
17389 {
17390 /* We can't call cp_finish_decl, so handle the
17391 initializer by hand. */
17406 }
17408 || processing_contract_condition
17415 }
17416 /* Remember this for subsequent uses. */
17419 }
17422 }
17423 else
17447 {
17448 /* Template template argument like the following example need
17449 special treatment:
17451 template <template <class> class TT> struct C {};
17452 template <class T> struct D {
17453 template <class U> struct E {};
17454 C<E> c; // #1
17455 };
17456 D<int> d; // #2
17458 We are processing the template argument `E' in #1 for
17459 the template instantiation #2. Originally, `E' is a
17460 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
17461 have to substitute this with one having context `D<int>'. */
17466 }
17467 else
17468 /* Ordinary template template argument. */
17473 {
17474 /* Handle location wrappers by substituting the wrapped node
17475 first, *then* reusing the resulting type. Doing the type
17476 first ensures that we handle template parameters and
17477 parameter pack expansions. */
17479 {
17483 }
17485 /* force_paren_expr can also create a VIEW_CONVERT_EXPR. */
17487 {
17492 }
17493 /* We shouldn't see any other uses of these in templates
17494 (tsubst_copy_and_build handles C++20 tparm object wrappers). */
17496 }
17504 CASE_CONVERT:
17505 {
17512 }
17515 {
17521 }
17526 {
17535 /* We only want to compute the number of arguments. */
17538 else
17545 {
17547 /* Set TREE_USED for the benefit of -Wunused. */
17551 }
17559 {
17564 else
17572 else
17577 }
17578 else
17580 }
17582 {
17590 }
17591 /* Fall through */
17607 {
17613 /* For addresses of immediate functions ensure we have EXPR_LOCATION
17614 set for possible later diagnostics. */
17621 }
17624 {
17628 {
17631 }
17633 }
17636 {
17637 tree object;
17638 tree name;
17643 {
17647 }
17650 {
17660 }
17665 in_decl);
17666 else
17669 }
17705 {
17709 }
17712 {
17717 }
17720 {
17724 }
17727 {
17735 }
17741 {
17748 }
17751 {
17758 }
17761 {
17768 }
17771 {
17772 /* Substituted template arguments */
17782 else
17784 }
17787 {
17807 }
17815 /* Fall through. */
17818 {
17821 }
17822 else
17826 /* This is handled by tsubst_copy_and_build. */
17830 {
17834 }
17837 /* We shouldn't have built any of these during initial template
17838 generation. Instead, they should be built during instantiation
17839 in response to the saved STMT_IS_FULL_EXPR_P setting. */
17843 {
17853 }
17871 {
17872 /* Instantiate any typedefs in the type. */
17877 }
17880 {
17884 {
17887 }
17889 }
17892 /* These can sometimes show up in a partial instantiation, but never
17893 involve template parms. */
17909 /* ??? There's no point in copying it for now, but maybe some
17910 day it will contain more information, such as a pointer back
17911 to the containing function, inlined copy or so. */
17918 /* We shouldn't get here, but keep going if !flag_checking. */
17922 }
17923 }
17925 /* Helper function for tsubst_omp_clauses, used for instantiation of
17926 OMP_CLAUSE_DECL of clauses. */
17928 static tree
17931 {
17935 /* Handle OpenMP iterators. */
17939 {
17940 tree ret;
17943 else
17944 {
17948 {
17962 }
17966 }
17970 }
17972 /* Handle an OpenMP array section represented as a TREE_LIST (or
17973 OMP_CLAUSE_DOACROSS_KIND). An OMP_CLAUSE_DOACROSS (with a depend
17974 kind of OMP_CLAUSE_DOACROSS_SINK) can also be represented as a
17975 TREE_LIST. We can handle it exactly the same as an array section
17976 (purpose, value, and a chain), even though the nomenclature
17977 (low_bound, length, etc) is different. */
17979 {
17980 tree low_bound
17993 }
17995 /* Undo convert_from_reference tsubst_expr could have called. */
18001 }
18003 /* Like tsubst_copy, but specifically for OpenMP clauses. */
18005 static tree
18008 {
18014 {
18020 {
18023 {
18029 }
18030 /* FALLTHRU */
18060 /* FALLTHRU */
18093 {
18096 {
18103 }
18104 else
18106 }
18133 {
18136 }
18141 else
18172 }
18175 {
18192 /* tsubst_expr on SCOPE_REF results in returning
18193 finish_non_static_data_member result. Undo that here. */
18197 {
18202 {
18206 CASE_CONVERT:
18215 /* FALLTHRU */
18219 }
18220 }
18226 {
18229 {
18232 }
18233 }
18237 }
18238 }
18242 {
18247 {
18250 }
18251 }
18253 }
18255 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
18257 static tree
18259 tree in_decl)
18260 {
18261 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
18279 {
18282 else
18283 {
18287 }
18288 }
18293 #undef RECUR
18294 }
18296 /* Used to temporarily communicate the list of #pragma omp parallel
18297 clauses to #pragma omp for instantiation if they are combined
18298 together. */
18305 /* Substitute one OMP_FOR iterator. */
18307 static bool
18311 {
18312 #define RECUR(NODE) \
18313 tsubst_expr ((NODE), args, complain, in_decl)
18325 {
18328 {
18333 {
18343 else
18345 {
18347 {
18353 }
18356 }
18357 }
18358 }
18362 }
18364 {
18365 /* We need to jump through some hoops to handle declarations in the
18366 init-statement, since we might need to handle auto deduction,
18367 but we need to keep control of initialization. */
18371 }
18372 else
18373 {
18375 {
18378 {
18382 {
18386 CASE_CONVERT:
18394 {
18397 }
18398 /* FALLTHRU */
18402 }
18403 }
18404 }
18405 else
18407 }
18409 {
18415 }
18416 else
18420 {
18426 NULL_TREE);
18427 else
18429 }
18432 {
18439 {
18444 }
18447 }
18457 {
18459 {
18460 /* Declare the variable, but don't let that initialize it. */
18465 }
18468 {
18472 {
18481 }
18482 else
18486 {
18491 }
18492 else
18496 }
18502 }
18505 {
18506 /* Declare and initialize the variable. */
18509 }
18511 {
18516 {
18518 {
18524 {
18527 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
18532 }
18535 {
18537 decl);
18539 }
18542 {
18544 decl);
18546 }
18547 else
18549 }
18552 }
18554 {
18557 ? OMP_CLAUSE_LASTPRIVATE
18562 {
18565 }
18566 }
18567 }
18570 {
18574 }
18575 else
18579 {
18590 {
18598 }
18599 else
18605 {
18611 }
18615 {
18623 }
18624 else
18630 }
18639 #undef RECUR
18640 }
18642 /* Helper function of tsubst_expr, find OMP_TEAMS inside
18643 of OMP_TARGET's body. */
18645 static tree
18647 {
18650 {
18659 }
18661 }
18663 /* Helper function for tsubst_expr. For decomposition declaration
18664 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
18665 also the corresponding decls representing the identifiers
18666 of the decomposition declaration. Return DECL if successful
18667 or error_mark_node otherwise, set *FIRST to the first decl
18668 in the list chained through DECL_CHAIN and *CNT to the number
18669 of such decls. */
18671 static tree
18675 {
18680 decl2
18685 {
18687 {
18690 }
18702 else
18703 {
18707 }
18714 {
18717 }
18718 else
18720 }
18723 }
18725 /* Return the proper local_specialization for init-capture pack DECL. */
18727 static tree
18729 {
18730 /* We handle normal pack captures by forwarding to the specialization of the
18731 captured parameter. We can't do that for pack init-captures; we need them
18732 to have their own local_specialization. We created the individual
18733 VAR_DECLs (if any) under build_capture_proxy, and we need to collect them
18734 when we process the DECL_EXPR for the pack init-capture in the template.
18735 So, how do we find them? We don't know the capture proxy pack when
18736 building the individual resulting proxies, and we don't know the
18737 individual proxies when instantiating the pack. What we have in common is
18738 the FIELD_DECL.
18740 So...when we instantiate the FIELD_DECL, we stick the result in
18741 local_specializations. Then at the DECL_EXPR we look up that result, see
18742 how many elements it has, synthesize the names, and look them up. */
18756 {
18761 }
18763 {
18768 else
18770 }
18772 }
18774 /* T is an operand of a template tree being substituted. Return whether
18775 T is dependent such that we should suppress some warnings that would
18776 make sense if the substituted expression were written directly, like
18777 template <int I> bool f() { return I == 2; }
18778 We don't want to warn when instantiating f that comparing two constants
18779 always has the same value.
18781 This is a more limited concept of dependence than instantiation-dependent;
18782 here we don't care whether substitution could fail. */
18784 static bool
18786 {
18795 }
18797 /* Like tsubst_copy for expressions, etc. but also does semantic
18798 processing. */
18800 tree
18802 {
18803 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
18804 #define RECUR(NODE) \
18805 tsubst_expr ((NODE), args, complain, in_decl)
18808 tree r;
18809 location_t loc;
18821 {
18823 {
18827 }
18856 else
18869 {
18874 }
18878 {
18880 tree init;
18886 {
18889 {
18893 {
18898 }
18900 }
18901 else
18902 {
18903 /* This is a non-dependent using-decl, and we'll have
18904 used the names it found during template parsing. We do
18905 not want to do the lookup again, because we might not
18906 find the things we found then. */
18909 /* We still need to push the bindings so that we can look up
18910 this name later. */
18913 }
18914 }
18917 {
18918 /* We're in tsubst_lambda_expr, we've already inserted a new
18919 capture proxy, so look it up and register it. */
18920 tree inst;
18922 {
18926 }
18928 {
18929 inst = (retrieve_local_specialization
18933 }
18934 else
18939 }
18946 /* Don't copy the old closure; we'll create a new one in
18947 tsubst_lambda_expr. */
18949 else
18950 {
18954 {
18955 /* By marking the declaration as instantiated, we avoid
18956 trying to instantiate it. Since instantiate_decl can't
18957 handle local variables, and since we've already done
18958 all that needs to be done, that's the right thing to
18959 do. */
18964 /* Anonymous aggregates are a special case. */
18967 {
18970 {
18974 }
18976 }
18981 {
18989 }
18990 else
18991 {
19013 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
19019 /* In a non-template function, VLA type declarations are
19020 handled in grokdeclarator; for templates, handle them
19021 now. */
19025 {
19029 asmspec_tree
19033 }
19039 }
19040 }
19041 }
19044 }
19054 {
19058 }
19063 {
19064 /* Construct another range_for, if this is not a final
19065 substitution (for inside a generic lambda of a
19066 template). Otherwise convert to a regular for. */
19068 stmt = (processing_template_decl
19085 {
19091 }
19092 else
19093 {
19099 }
19105 }
19112 {
19116 }
19122 {
19126 }
19138 {
19144 }
19147 {
19148 /* We're partially instantiating a generic lambda, but the condition
19149 of the constexpr if is still dependent. Don't substitute into the
19150 branches now, just remember the template arguments. */
19158 }
19162 {
19167 }
19168 else
19169 {
19177 }
19183 {
19193 }
19201 else
19209 else
19230 {
19236 {
19241 }
19242 }
19246 {
19248 tree label;
19255 }
19261 /* Computed goto's must be tsubst'd into. On the other hand,
19262 non-computed gotos must not be; the identifier in question
19263 will have no binding. */
19265 else
19271 {
19288 }
19293 {
19298 }
19299 else
19300 {
19305 else
19312 else
19318 else
19320 }
19324 {
19328 {
19330 /* Prevent instantiate_decl from trying to instantiate
19331 this variable. We've already done all that needs to be
19332 done. */
19335 }
19340 }
19346 {
19347 /* Local classes are not independent templates; they are
19348 instantiated along with their containing function. And this
19349 way we don't have to deal with pushing out of one local class
19350 to instantiate a member of another local class. */
19351 /* Closures are handled by the LAMBDA_EXPR. */
19355 {
19356 /* This is a partial instantiation, try again when full. */
19359 }
19373 }
19377 {
19378 tree condition;
19389 }
19396 in_decl);
19418 {
19425 }
19441 {
19455 in_decl);
19457 {
19464 }
19475 any_range_for
19482 {
19491 }
19492 else
19497 else
19504 else
19505 {
19513 }
19516 t));
19518 }
19524 /* FALLTHRU */
19534 in_decl);
19536 {
19541 }
19542 else
19543 {
19547 }
19552 {
19554 "%<#pragma omp critical%> with %<hint%> clause requires "
19557 }
19568 {
19571 {
19576 }
19577 else
19578 {
19582 }
19584 }
19585 else
19587 OMP_CLAUSE_DEPEND_INVALID,
19596 ? C_ORT_ACC
19615 {
19618 /* For combined target teams, ensure the num_teams and
19619 thread_limit clause expressions are evaluated on the host,
19620 before entering the target construct. */
19629 {
19632 tf_none);
19639 OMP_CLAUSE_FIRSTPRIVATE);
19643 }
19644 }
19681 {
19685 }
19686 else
19697 /* FALLTHRU */
19715 {
19721 {
19724 }
19726 {
19730 {
19733 }
19738 }
19739 else
19740 {
19743 }
19748 }
19749 else
19750 {
19757 {
19760 }
19763 {
19768 {
19771 }
19773 {
19777 {
19780 }
19785 }
19786 else
19787 {
19790 }
19794 }
19795 else
19796 {
19800 }
19804 }
19808 {
19814 {
19818 {
19823 }
19827 }
19828 else
19829 {
19834 }
19835 }
19839 {
19843 }
19856 /* If the first operand was a statement, we're done with it. */
19861 complain));
19877 }
19880 out:
19883 #undef RECUR
19884 #undef RETURN
19885 }
19887 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
19888 function. For description of the body see comment above
19889 cp_parser_omp_declare_reduction_exprs. */
19891 static void
19893 {
19899 tree_stmt_iterator tsi;
19910 {
19917 /* tsubsting a local var_decl leaves DECL_CONTEXT null, as we
19918 expect to be pushing it. */
19930 }
19932 {
19952 }
19953 }
19955 /* T is a postfix-expression that is not being used in a function
19956 call. Return the substituted version of T. */
19958 static tree
19960 tsubst_flags_t complain,
19961 tree in_decl)
19962 {
19966 else
19970 }
19972 /* Subroutine of tsubst_lambda_expr: add the FIELD/INIT capture pair to the
19973 LAMBDA_EXPR_CAPTURE_LIST passed in LIST. Do deduction for a previously
19974 dependent init-capture. EXPLICIT_P is true if the original list had
19975 explicit captures. */
19977 static void
19979 tsubst_flags_t complain)
19980 {
19982 {
19985 {
19989 }
19996 }
19999 }
20001 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
20002 instantiation context. Instantiating a pack expansion containing a lambda
20003 might result in multiple lambdas all based on the same lambda in the
20004 template. */
20006 tree
20008 {
20023 else
20034 {
20039 else
20051 {
20052 /* For a VLA, simply tsubsting the field type won't work, we need to
20053 go through add_capture again. XXX do we want to do this for all
20054 captures? */
20055 tree name = (get_identifier
20063 }
20070 {
20071 /* Remember these for when we've pushed local_specializations. */
20074 }
20080 {
20089 complain);
20090 }
20091 else
20092 {
20098 }
20099 }
20108 /* If we're pushed into another scope (PR105652), fix it. */
20113 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
20130 {
20133 }
20136 {
20139 }
20143 else
20144 {
20145 /* The body of a lambda-expression is not a subexpression of the
20146 enclosing expression. Parms are to have DECL_CHAIN tsubsted,
20147 which would be skipped if cp_unevaluated_operand. */
20148 cp_evaluated ev;
20150 /* Fix the type of 'this'. */
20154 tree inst = (oldtmpl
20159 {
20162 }
20168 /* Let finish_function set this. */
20174 else
20175 /* Still increment function_depth so that we don't GC in the
20176 middle of an expression. */
20186 /* Now record them for lookup_init_capture_pack. */
20189 {
20193 }
20199 {
20200 /* We might not partially instantiate some parts of the function, so
20201 copy these flags from the original template. */
20207 }
20209 /* [temp.deduct] A lambda-expression appearing in a function type or a
20210 template parameter is not considered part of the immediate context for
20211 the purposes of template argument deduction. */
20216 /* We already have a body block from start_lambda_function, we don't
20217 need another to confuse NRV (91217). */
20228 else
20231 /* The capture list was built up in reverse order; fix that now. */
20238 }
20240 out:
20246 }
20248 /* Subroutine of maybe_fold_fn_template_args. */
20250 static bool
20252 {
20255 {
20261 {
20264 }
20269 {
20273 }
20274 }
20277 }
20279 /* Try to do constant evaluation of any explicit template arguments in FN
20280 before overload resolution, to get any errors only once. Return true iff
20281 we didn't have any problems folding. */
20283 static bool
20285 {
20303 }
20305 /* Helper function for tsubst_copy_and_build CALL_EXPR and ARRAY_REF
20306 handling. */
20308 static void
20311 {
20314 {
20320 else
20321 {
20322 /* Expand the pack expansion and push each entry onto CALL_ARGS. */
20325 {
20330 {
20335 }
20336 }
20337 else
20338 /* A partial substitution. Add one entry. */
20340 }
20341 }
20342 }
20344 /* Like tsubst but deals with expressions and performs semantic
20345 analysis. */
20347 tree
20349 tree args,
20350 tsubst_flags_t complain,
20351 tree in_decl)
20352 {
20353 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
20354 #define RECUR(NODE) \
20355 tsubst_copy_and_build (NODE, args, complain, in_decl)
20358 location_t save_loc;
20367 /* N3276 decltype magic only applies to calls at the top level or on the
20368 right side of a comma. */
20373 {
20376 /* Fall through. */
20378 {
20379 tree decl;
20380 cp_id_kind idk;
20384 {
20387 }
20389 /* Look up the name. */
20392 /* By convention, expressions use ERROR_MARK_NODE to indicate
20393 failure, not NULL_TREE. */
20407 input_location);
20411 {
20415 }
20417 }
20420 {
20421 tree object;
20432 {
20437 }
20440 {
20447 /* If we built a function concept check, return the underlying
20448 template-id. So we can evaluate it as a function call. */
20453 }
20456 {
20458 complain);
20462 }
20465 {
20468 }
20469 else
20479 {
20480 /* C++20 P0846: we can encounter an IDENTIFIER_NODE here when
20481 name lookup found nothing when parsing the template name. */
20484 }
20485 else
20487 }
20490 {
20494 {
20495 /* A type conversion to reference type will be enclosed in
20496 such an indirect ref, but the substitution of the cast
20497 will have also added such an indirect ref. */
20499 }
20500 else
20509 }
20512 {
20516 }
20519 {
20523 {
20528 }
20530 /* We'll pass this to convert_nontype_argument again, we don't need
20531 to actually perform any conversion here. */
20539 flags));
20540 }
20543 {
20549 }
20556 {
20557 tree type;
20571 {
20591 }
20594 }
20597 {
20601 }
20626 {
20633 }
20636 /* convert_like should have created an IMPLICIT_CONV_EXPR. */
20647 else
20649 in_decl);
20684 {
20685 /* If either OP0 or OP1 was value- or type-dependent, suppress
20686 warnings that depend on the range of the types involved. */
20700 tree r = build_x_binary_op
20702 op0,
20704 ? ERROR_MARK
20706 op1,
20708 ? ERROR_MARK
20717 }
20720 {
20728 }
20744 {
20746 releasing_vec index_exp_list;
20748 index_exp_list);
20750 tree r;
20756 else
20761 }
20770 /* Fall through */
20773 {
20774 tree r;
20782 {
20783 /* When there are no ARGS, we are trying to evaluate a
20784 non-dependent expression from the parser. Trying to do
20785 the substitutions may not work. */
20788 }
20789 else
20790 {
20795 else
20799 }
20804 else
20809 {
20811 {
20813 {
20817 }
20818 else
20822 }
20824 }
20826 }
20829 {
20837 }
20851 {
20856 tree r = build_x_modify_expr
20860 /* TREE_NO_WARNING must be set if either the expression was
20861 parenthesized or it uses an operator such as >>= rather
20862 than plain assignment. In the former case, it was already
20863 set and must be copied. In the latter case,
20864 build_x_modify_expr sets it and it must not be reset
20865 here. */
20870 }
20875 /* Remember that there was a reference to this entity. */
20882 {
20887 tree ret;
20894 else
20895 {
20899 }
20901 /* If there was an initializer in the original tree, but it
20902 instantiated to an empty list, then we should pass a
20903 non-NULL empty vector to tell build_new that it was an
20904 empty initializer() rather than no initializer. This can
20905 only happen when the initializer is a pack expansion whose
20906 parameter packs are of length zero. */
20911 else
20912 {
20916 else
20917 {
20920 }
20921 }
20923 /* Avoid passing an enclosing decl to valid_array_size_p. */
20930 complain);
20938 }
20941 {
20947 complain));
20948 }
20951 {
20955 op0,
20959 }
20962 {
20963 tree function;
20967 tree ret;
20970 /* Internal function with no arguments. */
20974 /* When we parsed the expression, we determined whether or
20975 not Koenig lookup should be performed. */
20978 {
20981 }
20983 {
20988 }
20993 {
20994 /* Do nothing; calling tsubst_copy_and_build on an identifier
20995 would incorrectly perform unqualified lookup again.
20997 Note that we can also have an IDENTIFIER_NODE if the earlier
20998 unqualified lookup found a dependent local extern declaration
20999 (as per finish_call_expr); in that case koenig_p will be false
21000 and we do want to do the lookup again to find the substituted
21001 declaration. */
21005 /* Use tsubst_copy to substitute through the template arguments
21006 of the template-id without performing unqualified lookup of
21007 the template name. */
21009 }
21010 else
21011 {
21013 {
21019 }
21020 else
21025 /* Avoid error about taking the address of a constructor. */
21030 /* When KOENIG_P, we don't want to mark_used the callee before
21031 augmenting the overload set via ADL, so during this initial
21032 substitution we disable mark_used by setting tf_conv (68942). */
21038 }
21041 releasing_vec call_args;
21043 call_args);
21045 /* Stripped-down processing for a call in a thunk. Specifically, in
21046 the thunk template for a generic lambda. */
21048 {
21049 /* Now that we've expanded any packs, the number of call args
21050 might be different. */
21054 {
21061 }
21062 /* We aren't going to do normal overload resolution, so force the
21063 template-id to resolve. */
21066 {
21067 /* In a thunk, pass through args directly, without any
21068 conversions. */
21073 }
21075 {
21076 /* If there are no other args, just push 'this'. */
21079 else
21080 {
21081 /* Otherwise, shift the other args over to make room. */
21087 }
21088 }
21091 /* The thunk location is not interesting. */
21098 }
21100 /* We do not perform argument-dependent lookup if normal
21101 lookup finds a non-function, in accordance with the
21102 resolution of DR 218. */
21105 /* If lookup found a member function, the Koenig lookup is
21106 not appropriate, even if an unqualified-name was used
21107 to denote the function. */
21110 /* C++20 P0846: Lookup found nothing. */
21113 /* Only do this when substitution turns a dependent call
21114 into a non-dependent call. */
21126 {
21131 {
21132 /* For backwards compatibility and good diagnostics, try
21133 the unqualified lookup again if we aren't in SFINAE
21134 context. */
21141 {
21144 "and no declarations were found by "
21145 "argument-dependent lookup at the point "
21150 /* In a lambda fn, we have to be careful to not
21151 introduce new this captures. Legacy code can't
21152 be using lambdas anyway, so it's ok to be
21153 stricter. Be strict with C++20 template-id ADL too.
21154 And be strict if we're already failing anyway. */
21160 else
21164 {
21175 {
21178 "declarations in dependent base %qT are "
21184 else
21188 }
21189 else
21191 "%qD declared here, later in the "
21195 }
21198 }
21199 }
21201 {
21205 }
21206 }
21208 /* Remember that there was a reference to this entity. */
21217 /* Put back tf_decltype for the actual call. */
21222 {
21226 {
21228 "wrong number of arguments to "
21231 }
21232 else
21240 {
21242 "wrong number of arguments to "
21246 }
21250 complain);
21256 {
21258 complain);
21262 }
21267 {
21269 "wrong number of arguments to "
21272 }
21273 else
21274 {
21279 {
21282 }
21285 }
21289 /* Unsupported internal function with arguments. */
21291 }
21296 complain);
21298 {
21313 complain);
21314 else
21315 ret = (build_new_method_call
21320 complain));
21321 }
21323 {
21324 /* FUNCTION is a template-id referring to a concept definition. */
21329 /* Calls to standard and variable concepts should have been
21330 previously diagnosed. */
21333 /* Ensure the result is wrapped as a call expression. */
21335 }
21336 else
21339 koenig_p,
21340 complain);
21343 {
21349 {
21353 }
21355 /* This also suppresses -Wredundant-move. */
21357 }
21360 }
21363 {
21370 {
21372 {
21377 }
21378 else
21379 {
21384 }
21386 }
21387 else
21388 {
21391 }
21396 }
21399 {
21404 input_location));
21405 }
21411 {
21412 tree object;
21413 tree object_type;
21414 tree member;
21415 tree r;
21419 /* Remember that there was a reference to this entity. */
21430 else
21437 {
21440 }
21442 {
21444 complain);
21448 }
21452 {
21454 {
21459 {
21462 }
21464 {
21469 }
21470 }
21471 }
21474 {
21475 /* Lookup the template functions now that we know what the
21476 scope is. */
21483 {
21486 args);
21487 member = (adjust_result_of_qualified_name_lookup
21489 object_type));
21490 }
21491 else
21492 {
21494 input_location);
21496 }
21497 }
21501 {
21503 {
21507 else
21510 }
21512 }
21516 complain);
21520 }
21527 {
21534 tree r;
21543 /* We do not want to process the index of aggregate
21544 initializers as they are identifier nodes which will be
21545 looked up by digest_init. */
21549 {
21552 }
21557 {
21559 /* An identifier index is looked up in the type
21560 being initialized, not the current scope. */
21565 {
21566 /* Substitute into the pack expansion. */
21568 in_decl);
21572 ;
21574 /* Just move the argument into place. */
21576 else
21577 {
21578 /* Update the length of the final CONSTRUCTOR
21579 arguments vector, and note that we will need to
21580 copy.*/
21583 }
21584 }
21585 else
21587 }
21590 {
21595 {
21597 {
21602 }
21603 else
21605 }
21606 }
21614 {
21619 }
21623 }
21626 {
21629 {
21632 }
21633 else
21634 {
21637 }
21638 }
21643 /* Fall through */
21646 {
21648 /* ??? We're doing a subset of finish_id_expression here. */
21650 /* Replace an evaluated use of the thread_local variable with
21651 a call to its wrapper. */
21657 /* If the original type was a reference, we'll be wrapped in
21658 the appropriate INDIRECT_REF. */
21661 }
21664 {
21668 }
21671 {
21672 tree object_ptr
21678 }
21685 {
21692 }
21695 {
21704 /* If the resulting list of expression statement is empty,
21705 fold it further into void_node. */
21710 }
21713 {
21715 {
21716 /* We don't have a full set of template arguments yet; don't touch
21717 the lambda at all. */
21720 }
21724 }
21732 else
21733 /* Recreate the PAREN_EXPR from __builtin_assoc_barrier. */
21734 {
21738 }
21741 {
21746 complain));
21747 }
21750 {
21753 }
21756 /* No need to substitute further, a RANGE_EXPR will always be built
21757 with constant operands. */
21762 {
21766 /* We need to do this here as well as in tsubst_copy so we get the
21767 other tsubst_copy_and_build semantics for a PARM_DECL operand. */
21772 /* force_paren_expr can also create a VIEW_CONVERT_EXPR. */
21775 /* Otherwise, we're dealing with a wrapper to make a C++20 template
21776 parameter object const. */
21779 {
21780 /* The template argument is not const, presumably because
21781 it is still dependent, and so not the const template parm
21782 object. */
21786 {
21787 /* Don't add a wrapper to these. */
21790 }
21791 else
21792 /* Do add a wrapper otherwise (in particular, if op is
21793 another TEMPLATE_PARM_INDEX). */
21795 }
21797 }
21800 /* Handle Objective-C++ constructs, if appropriate. */
21801 {
21802 tree subst
21806 }
21808 }
21810 #undef RECUR
21811 #undef RETURN
21812 out:
21815 }
21817 /* Verify that the instantiated ARGS are valid. For type arguments,
21818 make sure that the type's linkage is ok. For non-type arguments,
21819 make sure they are constants if they are integral or enumerations.
21820 Emit an error under control of COMPLAIN, and return TRUE on error. */
21822 static bool
21824 {
21828 {
21838 }
21840 {
21841 /* [basic.link]: A name with no linkage (notably, the name
21842 of a class or enumeration declared in a local scope)
21843 shall not be used to declare an entity with linkage.
21844 This implies that names with no linkage cannot be used as
21845 template arguments
21847 DR 757 relaxes this restriction for C++0x. */
21852 {
21853 /* DR 488 makes use of a type with no linkage cause
21854 type deduction to fail. */
21856 {
21859 else
21862 }
21864 }
21865 /* In order to avoid all sorts of complications, we do not
21866 allow variably-modified types as template arguments. */
21868 {
21872 }
21873 }
21874 /* Class template and alias template arguments should be OK. */
21876 ;
21877 /* A non-type argument of integral or enumerated type must be a
21878 constant. */
21883 {
21887 }
21889 }
21891 static bool
21893 {
21898 {
21901 }
21905 }
21907 /* Call mark_used on each entity within the non-type template arguments in
21908 ARGS for an instantiation of TMPL, to ensure that each such entity is
21909 considered odr-used (and therefore marked for instantiation) regardless of
21910 whether the specialization was first formed in a template context (which
21911 inhibits mark_used).
21913 This function assumes push_to_top_level has been called beforehand. */
21915 static void
21917 {
21918 /* It suffices to do this only when instantiating a primary template. */
21922 /* We already marked outer arguments when specializing the context. */
21926 {
21927 /* A (pointer/reference to) function or variable NTTP argument. */
21930 {
21936 {
21937 /* Pass tf_none to avoid duplicate diagnostics: if this call
21938 fails then an earlier call to mark_used for this argument
21939 must have also failed and emitted a diagnostic. */
21942 }
21943 }
21944 /* A class NTTP argument. */
21947 {
21950 {
21953 }
21955 };
21958 }
21959 }
21960 }
21962 /* We're out of SFINAE context now, so generate diagnostics for the access
21963 errors we saw earlier when instantiating D from TMPL and ARGS. */
21965 static void
21967 {
21979 }
21981 /* Instantiate the indicated variable, function, or alias template TMPL with
21982 the template arguments in TARG_PTR. */
21984 tree
21986 {
21990 tree fndecl;
21991 tree gen_tmpl;
21992 tree spec;
22003 /* If this function is a clone, handle it specially. */
22005 {
22006 tree spec;
22007 tree clone;
22009 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
22010 DECL_CLONED_FUNCTION. */
22016 /* Look for the clone. */
22020 /* We should always have found the clone by now. */
22023 }
22028 /* Check to see if we already have this specialization. */
22032 /* targ_ptr only has the innermost template args, so add the outer ones
22033 from tmpl, which could be either a partial instantiation or gen_tmpl (in
22034 the case of a non-dependent call within a template definition). */
22035 targ_ptr = (add_outermost_template_args
22037 targ_ptr));
22039 /* It would be nice to avoid hashing here and then again in tsubst_decl,
22040 but it doesn't seem to be on the hot path. */
22044 || ((fndecl
22050 {
22052 {
22056 }
22058 }
22061 complain))
22064 /* We are building a FUNCTION_DECL, during which the access of its
22065 parameters and return types have to be checked. However this
22066 FUNCTION_DECL which is the desired context for access checking
22067 is not built yet. We solve this chicken-and-egg problem by
22068 deferring all checks until we have the FUNCTION_DECL. */
22071 /* Instantiation of the function happens in the context of the function
22072 template, not the context of the overload resolution we're doing. */
22074 /* If there are dependent arguments, e.g. because we're doing partial
22075 ordering, make sure processing_template_decl stays set. */
22079 {
22080 tree ctx;
22082 /* If the context of the partially instantiated template is
22083 already non-dependent, then we might as well use it. */
22085 else
22089 }
22096 {
22097 /* We need to determine if we're using a partial or explicit
22098 specialization now, because the type of the variable could be
22099 different. */
22105 {
22110 }
22111 }
22113 /* Substitute template parameters to obtain the specialization. */
22121 {
22124 }
22126 /* The DECL_TI_TEMPLATE should always be the immediate parent
22127 template, not the most general template. */
22131 /* Now that we we've formed this variable template specialization,
22132 remember the result of most_specialized_partial_spec for it. */
22137 /* Now we know the specialization, compute access previously
22138 deferred. Do no access control for inheriting constructors,
22139 as we already checked access for the inherited constructor. */
22142 {
22147 }
22150 /* If we've just instantiated the main entry point for a function,
22151 instantiate all the alternate entry points as well. We do this
22152 by cloning the instantiation of the main entry point, not by
22153 instantiating the template clones. */
22159 {
22161 {
22162 /* Remember to reinstantiate when we're out of SFINAE so the user
22163 can see the errors. */
22165 }
22167 }
22170 }
22172 /* Instantiate the alias template TMPL with ARGS. Also push a template
22173 instantiation level, which instantiate_template doesn't do because
22174 functions and variables have sufficient context established by the
22175 callers. */
22177 static tree
22179 {
22188 /* FIXME check for satisfaction in check_instantiated_args. */
22190 {
22192 {
22193 auto_diagnostic_group d;
22196 }
22198 }
22206 {
22207 /* An alias template specialization can be dependent
22208 even if its underlying type is not. */
22211 /* Sometimes a dependent alias spec is equivalent to its expansion,
22212 sometimes not. So always use structural_comptypes. */
22214 }
22217 }
22219 /* PARM is a template parameter pack for FN. Returns true iff
22220 PARM is used in a deducible way in the argument list of FN. */
22222 static bool
22224 {
22227 {
22229 tree packs;
22235 {
22236 /* The template parameter pack is used in a function parameter
22237 pack. If this is the end of the parameter list, the
22238 template parameter pack is deducible. */
22241 else
22242 /* Otherwise, not. Well, it could be deduced from
22243 a non-pack parameter, but doing so would end up with
22244 a deduction mismatch, so don't bother. */
22246 }
22247 }
22248 /* The template parameter pack isn't used in any function parameter
22249 packs, but it might be used deeper, e.g. tuple<Args...>. */
22251 }
22253 /* Subroutine of fn_type_unification: check non-dependent parms for
22254 convertibility. */
22256 static int
22260 {
22261 /* Non-constructor methods need to leave a conversion for 'this', which
22262 isn't included in nargs here. */
22268 {
22274 /* For a function parameter pack that occurs at the end of the
22275 parameter-declaration-list, the type A of each remaining
22276 argument of the call is compared with the type P of the
22277 declarator-id of the function parameter pack. */
22283 /* For a function parameter pack that does not occur at the
22284 end of the parameter-declaration-list, the type of the
22285 parameter pack is a non-deduced context. */
22289 {
22297 }
22300 }
22303 }
22305 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
22306 NARGS elements of the arguments that are being used when calling
22307 it. TARGS is a vector into which the deduced template arguments
22308 are placed.
22310 Returns either a FUNCTION_DECL for the matching specialization of FN or
22311 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
22312 true, diagnostics will be printed to explain why it failed.
22314 If FN is a conversion operator, or we are trying to produce a specific
22315 specialization, RETURN_TYPE is the return type desired.
22317 The EXPLICIT_TARGS are explicit template arguments provided via a
22318 template-id.
22320 The parameter STRICT is one of:
22322 DEDUCE_CALL:
22323 We are deducing arguments for a function call, as in
22324 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
22325 deducing arguments for a call to the result of a conversion
22326 function template, as in [over.call.object].
22328 DEDUCE_CONV:
22329 We are deducing arguments for a conversion function, as in
22330 [temp.deduct.conv].
22332 DEDUCE_EXACT:
22333 We are deducing arguments when doing an explicit instantiation
22334 as in [temp.explicit], when determining an explicit specialization
22335 as in [temp.expl.spec], or when taking the address of a function
22336 template, as in [temp.deduct.funcaddr]. */
22338 tree
22340 tree explicit_targs,
22341 tree targs,
22344 tree return_type,
22345 unification_kind_t strict,
22350 {
22351 tree parms;
22352 tree fntype;
22357 /* type_unification_real will pass back any access checks from default
22358 template argument substitution. */
22360 /* We don't have all the template args yet. */
22373 full_targs = (add_outermost_template_args
22375 targs));
22380 /* In C++0x, it's possible to have a function template whose type depends
22381 on itself recursively. This is most obvious with decltype, but can also
22382 occur with enumeration scope (c++/48969). So we need to catch infinite
22383 recursion and reject the substitution at deduction time; this function
22384 will return error_mark_node for any repeated substitution.
22386 This also catches excessive recursion such as when f<N> depends on
22387 f<N-1> across all integers, and returns error_mark_node for all the
22388 substitutions back up to the initial one.
22390 This is, of course, not reentrant. */
22399 {
22400 /* [temp.deduct]
22402 The specified template arguments must match the template
22403 parameters in kind (i.e., type, nontype, template), and there
22404 must not be more arguments than there are parameters;
22405 otherwise type deduction fails.
22407 Nontype arguments must match the types of the corresponding
22408 nontype template parameters, or must be convertible to the
22409 types of the corresponding nontype parameters as specified in
22410 _temp.arg.nontype_, otherwise type deduction fails.
22412 All references in the function type of the function template
22413 to the corresponding template parameters are replaced by the
22414 specified template argument values. If a substitution in a
22415 template parameter or in the function type of the function
22416 template results in an invalid type, type deduction fails. */
22427 explicit_targs);
22429 /* Adjust any explicit template arguments before entering the
22430 substitution context. */
22431 explicit_targs
22438 /* Substitute the explicit args into the function type. This is
22439 necessary so that, for instance, explicitly declared function
22440 arguments can match null pointed constants. If we were given
22441 an incomplete set of explicit args, we must not do semantic
22442 processing during substitution as we could create partial
22443 instantiations. */
22445 {
22450 /* Dig out the actual parm. */
22453 {
22456 }
22458 {
22461 }
22464 /* No explicit argument for this template parameter. */
22467 {
22468 /* Mark the argument pack as "incomplete". We could
22469 still deduce more arguments during unification.
22470 We remove this mark in type_unification_real. */
22475 /* We have some incomplete argument packs. */
22477 }
22478 }
22481 {
22483 {
22486 }
22489 /* Ignore any access checks; we'll see them again in
22490 instantiate_template and they might have the wrong
22491 access path at this point. */
22502 }
22504 /* Place the explicitly specified arguments in TARGS. */
22510 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
22512 }
22515 {
22521 }
22526 /* Never do unification on the 'this' parameter. */
22530 {
22531 /* We're deducing for a call to the result of a template conversion
22532 function. The parms we really want are in return_type. */
22536 }
22538 {
22540 }
22542 /* We allow incomplete unification without an error message here
22543 because the standard doesn't seem to explicitly prohibit it. Our
22544 callers must be ready to deal with unification failures in any
22545 event. */
22547 /* If we aren't explaining yet, push tinst context so we can see where
22548 any errors (e.g. from class instantiations triggered by instantiation
22549 of default template arguments) come from. If we are explaining, this
22550 context is redundant. */
22552 {
22555 }
22565 /* Now that we have bindings for all of the template arguments,
22566 ensure that the arguments deduced for the template template
22567 parameters have compatible template parameter lists. We cannot
22568 check this property before we have deduced all template
22569 arguments, because the template parameter types of a template
22570 template parameter might depend on prior template parameters
22571 deduced after the template template parameter. The following
22572 ill-formed example illustrates this issue:
22574 template<typename T, template<T> class C> void f(C<5>, T);
22576 template<int N> struct X {};
22578 void g() {
22579 f(X<5>(), 5l); // error: template argument deduction fails
22580 }
22582 The template parameter list of 'C' depends on the template type
22583 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
22584 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
22585 time that we deduce 'C'. */
22588 {
22591 }
22593 deduced:
22595 /* CWG2369: Check satisfaction before non-deducible conversions. */
22597 {
22601 }
22603 /* DR 1391: All parameters have args, now check non-dependent parms for
22604 convertibility. We don't do this if all args were explicitly specified,
22605 as the standard says that we substitute explicit args immediately. */
22611 /* All is well so far. Now, check:
22613 [temp.deduct]
22615 When all template arguments have been deduced, all uses of
22616 template parameters in nondeduced contexts are replaced with
22617 the corresponding deduced argument values. If the
22618 substitution results in an invalid type, as described above,
22619 type deduction fails. */
22621 {
22624 }
22626 /* Also collect access checks from the instantiation. */
22639 /* Now perform any access checks encountered during substitution. */
22646 /* If we're looking for an exact match, check that what we got
22647 is indeed an exact match. It might not be if some template
22648 parameters are used in non-deduced contexts. But don't check
22649 for an exact match if we have dependent template arguments;
22650 in that case we're doing partial ordering, and we already know
22651 that we have two candidates that will provide the actual type. */
22653 {
22657 tree sarg
22663 {
22667 }
22669 /* add_candidates uses DEDUCE_EXACT for x.operator foo(), but args
22670 doesn't contain the trailing void, and conv fns are always (). */
22672 {
22676 }
22677 }
22679 /* After doing deduction with the inherited constructor, actually return an
22680 instantiation of the inheriting constructor. */
22686 fail:
22689 {
22691 /* Reset once we're all the way out. */
22693 }
22696 }
22698 /* Returns true iff PARM is a forwarding reference in the context of
22699 template argument deduction for TMPL. */
22701 static bool
22703 {
22704 /* [temp.deduct.call], "A forwarding reference is an rvalue reference to a
22705 cv-unqualified template parameter ..." */
22710 {
22712 /* [temp.deduct.call], "... that does not represent a template parameter
22713 of a class template (during class template argument deduction)." */
22717 {
22718 /* Since the template parameters of a synthesized guide consist of
22719 the template parameters of the class template followed by those of
22720 the constructor (if any), we can tell if PARM represents a template
22721 parameter of the class template by comparing its index with the
22722 arity of the class template. */
22727 }
22729 }
22731 }
22733 /* Adjust types before performing type deduction, as described in
22734 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
22735 sections are symmetric. PARM is the type of a function parameter
22736 or the return type of the conversion function. ARG is the type of
22737 the argument passed to the call, or the type of the value
22738 initialized with the result of the conversion function.
22739 ARG_EXPR is the original argument expression, which may be null. */
22741 static int
22743 unification_kind_t strict,
22746 tree arg_expr)
22747 {
22751 {
22756 /* [temp.deduct.conv] First remove a reference type on parm.
22757 DRs 322 & 976 affected this. */
22761 /* Swap PARM and ARG throughout the remainder of this
22762 function; the handling is precisely symmetric since PARM
22763 will initialize ARG rather than vice versa. */
22769 /* Core issue #873: Do the DR606 thing (see below) for these cases,
22770 too, but here handle it by stripping the reference from PARM
22771 rather than by adding it to ARG. */
22776 /* Nothing else to do in this case. */
22781 }
22784 {
22785 /* [temp.deduct.call]
22787 If P is not a reference type:
22789 --If A is an array type, the pointer type produced by the
22790 array-to-pointer standard conversion (_conv.array_) is
22791 used in place of A for type deduction; otherwise,
22793 --If A is a function type, the pointer type produced by
22794 the function-to-pointer standard conversion
22795 (_conv.func_) is used in place of A for type deduction;
22796 otherwise,
22798 --If A is a cv-qualified type, the top level
22799 cv-qualifiers of A's type are ignored for type
22800 deduction. */
22805 else
22807 }
22809 /* [temp.deduct.call], "If P is a forwarding reference and the argument is
22810 an lvalue, the type 'lvalue reference to A' is used in place of A for
22811 type deduction." */
22814 /* try_one_overload doesn't provide an arg_expr, but
22815 functions are always lvalues. */
22819 /* [temp.deduct.call]
22821 If P is a cv-qualified type, the top level cv-qualifiers
22822 of P's type are ignored for type deduction. If P is a
22823 reference type, the type referred to by P is used for
22824 type deduction. */
22827 {
22830 }
22833 }
22835 /* Subroutine of fn_type_unification. PARM is a function parameter of a
22836 template which doesn't contain any deducible template parameters; check if
22837 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
22838 unify_one_argument. */
22840 static int
22844 {
22845 tree type;
22849 else
22857 {
22860 }
22862 {
22866 /* Avoid recalculating this in add_function_candidate. */
22867 ok = (*conv_p
22869 else
22873 }
22877 else
22879 }
22883 /* Returns true iff the expression EXPR is one from which a template
22884 argument can be deduced. In other words, if it's an undecorated
22885 use of a template non-type parameter. */
22887 static bool
22889 {
22890 /* Strip implicit conversions and implicit INDIRECT_REFs. */
22896 }
22898 /* Returns true iff the array domain DOMAIN uses a template parameter in a
22899 deducible way; that is, if it has a max value of <PARM> - 1. */
22901 static bool
22903 {
22912 }
22914 /* Returns true iff the template arguments ARGS use a template parameter
22915 in a deducible way. */
22917 static bool
22919 {
22921 {
22925 else
22926 {
22933 else
22935 }
22938 }
22940 }
22942 /* Returns true iff TYPE contains any deducible references to template
22943 parameters, as per 14.8.2.5. */
22945 static bool
22947 {
22951 /* T
22952 cv-list T
22953 TT<T>
22954 TT<i>
22955 TT<> */
22960 /* T*
22961 T&
22962 T&& */
22966 /* T[integer-constant ]
22967 type [i] */
22972 /* T type ::*
22973 type T::*
22974 T T::*
22975 T (type ::*)()
22976 type (T::*)()
22977 type (type ::*)(T)
22978 type (T::*)(T)
22979 T (type ::*)(T)
22980 T (T::*)()
22981 T (T::*)(T) */
22984 || (uses_deducible_template_parms
22987 /* template-name <T> (where template-name refers to a class template)
22988 template-name <i> (where template-name refers to a class template) */
22995 /* type (T)
22996 T()
22997 T(T) */
22999 {
23013 }
23016 }
23018 /* Subroutine of type_unification_real and unify_pack_expansion to
23019 handle unification of a single P/A pair. Parameters are as
23020 for those functions. */
23022 static int
23026 {
23033 /* We can't deduce anything from this, but we might get all the
23034 template args from other function args. */
23037 /* Implicit conversions (Clause 4) will be performed on a function
23038 argument to convert it to the type of the corresponding function
23039 parameter if the parameter type contains no template-parameters that
23040 participate in template argument deduction. */
23043 /* For function parameters with no deducible template parameters,
23044 just return. We'll check non-dependent conversions later. */
23048 {
23050 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
23051 | UNIFY_ALLOW_MORE_CV_QUAL
23065 }
23067 /* We only do these transformations if this is the top-level
23068 parameter_type_list in a call or declaration matching; in other
23069 situations (nested function declarators, template argument lists) we
23070 won't be comparing a type to an expression, and we don't do any type
23071 adjustments. */
23073 {
23075 {
23078 {
23079 /* [temp.deduct.type] A template-argument can be
23080 deduced from a pointer to function or pointer
23081 to member function argument if the set of
23082 overloaded functions does not contain function
23083 templates and at most one of a set of
23084 overloaded functions provides a unique
23085 match. */
23089 /* If a unique match was not found, this is a
23090 non-deduced context, so we still succeed. */
23092 }
23098 }
23102 }
23103 else
23108 /* For deduction from an init-list we need the actual list. */
23112 }
23114 /* for_each_template_parm callback that always returns 0. */
23116 static int
23118 {
23120 }
23122 /* for_each_template_parm any_fn callback to handle deduction of a template
23123 type argument from the type of an array bound. */
23125 static int
23127 {
23135 {
23141 }
23143 /* Keep walking. */
23145 }
23147 /* Try to deduce any not-yet-deduced template type arguments from the type of
23148 an array bound. This is handled separately from unify because 14.8.2.5 says
23149 "The type of a type parameter is only deduced from an array bound if it is
23150 not otherwise deduced." */
23152 static void
23154 {
23159 }
23161 /* Most parms like fn_type_unification.
23163 If SUBR is 1, we're being called recursively (to unify the
23164 arguments of a function or method parameter of a function
23165 template).
23167 CHECKS is a pointer to a vector of access checks encountered while
23168 substituting default template arguments. */
23170 static int
23172 tree full_targs,
23173 tree xparms,
23177 unification_kind_t strict,
23180 {
23185 tree parms;
23196 /* Reset the number of non-defaulted template arguments contained
23197 in TARGS. */
23200 again:
23205 /* Only fn_type_unification cares about terminal void. */
23212 {
23217 /* For a function parameter pack that occurs at the end of the
23218 parameter-declaration-list, the type A of each remaining
23219 argument of the call is compared with the type P of the
23220 declarator-id of the function parameter pack. */
23226 /* For a function parameter pack that does not occur at the
23227 end of the parameter-declaration-list, the type of the
23228 parameter pack is a non-deduced context. */
23235 explain_p))
23237 }
23242 {
23243 /* Unify the remaining arguments with the pack expansion type. */
23244 tree argvec;
23247 /* Allocate a TREE_VEC and copy in all of the arguments */
23252 /* Copy the parameter into parmvec. */
23258 /* Advance to the end of the list of parameters. */
23260 }
23262 /* Fail if we've reached the end of the parm list, and more args
23263 are present, and the parm list isn't variadic. */
23266 /* Fail if parms are left and they don't have default values and
23267 they aren't all deduced as empty packs (c++/57397). This is
23268 consistent with sufficient_parms_p. */
23271 {
23275 do
23276 {
23279 count++;
23281 }
23285 type_pack_p);
23286 }
23289 {
23290 tsubst_flags_t complain = (explain_p
23291 ? tf_warning_or_error
23296 {
23300 /* Clear the "incomplete" flags on all argument packs now so that
23301 substituting them into later default arguments works. */
23303 {
23306 }
23314 {
23319 }
23321 /* If this is an undeduced nontype parameter that depends on
23322 a type parameter, try another pass; its type may have been
23323 deduced from a later argument than the one from which
23324 this parameter can be deduced. */
23329 {
23332 }
23334 /* Core issue #226 (C++0x) [temp.deduct]:
23336 If a template argument has not been deduced, its
23337 default template argument, if any, is used.
23339 When we are in C++98 mode, TREE_PURPOSE will either
23340 be NULL_TREE or ERROR_MARK_NODE, so we do not need
23341 to explicitly check cxx_dialect here. */
23343 /* OK, there is a default argument. Wait until after the
23344 conversion check to do substitution. */
23347 /* If the type parameter is a parameter pack, then it will
23348 be deduced to an empty parameter pack. */
23350 {
23351 tree arg;
23354 {
23357 }
23358 else
23365 }
23368 }
23370 /* During partial ordering, we deduce dependent template args. */
23373 /* Now substitute into the default template arguments. */
23375 {
23380 {
23384 }
23399 {
23400 /* The type of this non-type parameter depends on undeduced
23401 parameters. Don't try to use its default argument yet,
23402 since we might deduce an argument for it on the next pass,
23403 but do check whether the arguments we already have cause
23404 substitution failure, so that that happens before we try
23405 later default arguments (78489). */
23408 NULL_TREE);
23412 else
23414 }
23415 else
23416 {
23417 /* Even if the call is happening in template context, getting
23418 here means it's non-dependent, and a default argument is
23419 considered a separate definition under [temp.decls], so we can
23420 do this substitution without processing_template_decl. This
23421 is important if the default argument contains something that
23422 might be instantiation-dependent like access (87480). */
23426 {
23427 /* First instatiate in template context, in case we still
23428 depend on undeduced template parameters. */
23431 NULL_TREE);
23435 /* We replaced all the tparms, substitute again out of
23436 template context. */
23438 }
23441 NULL_TREE);
23450 }
23459 {
23461 /* The position of the first default template argument,
23462 is also the number of non-defaulted arguments in TARGS.
23463 Record that. */
23466 }
23467 }
23471 }
23477 }
23479 /* Subroutine of type_unification_real. Args are like the variables
23480 at the call site. ARG is an overloaded function (or template-id);
23481 we try deducing template args from each of the overloads, and if
23482 only one succeeds, we go with that. Modifies TARGS and returns
23483 true on success. */
23485 static bool
23487 tree targs,
23488 tree parm,
23489 tree arg,
23490 unification_kind_t strict,
23493 {
23500 {
23503 }
23504 else
23508 /* Handle `&x' where `x' is some static or non-static member
23509 function name. */
23515 /* Strip baselink information. */
23520 {
23521 /* If we got some explicit template args, we need to plug them into
23522 the affected templates before we try to unify, in case the
23523 explicit args will completely resolve the templates in question. */
23530 {
23541 {
23546 {
23547 /* Instantiate the function to deduce its return type. */
23551 }
23560 {
23563 }
23564 }
23567 }
23568 /* If no templates (or more than one) are fully resolved by the
23569 explicit arguments, this template-id is a non-deduced context; it
23570 could still be OK if we deduce all template arguments for the
23571 enclosing call through other arguments. */
23574 }
23576 /* If ARG is, for example, "(0, &f)" then its type will be unknown
23577 -- but the deduction does not succeed because the expression is
23578 not just the function on its own. */
23580 else
23582 {
23587 {
23590 }
23591 }
23593 /* [temp.deduct.type] A template-argument can be deduced from a pointer
23594 to function or pointer to member function argument if the set of
23595 overloaded functions does not contain function templates and at most
23596 one of a set of overloaded functions provides a unique match.
23598 So if we found multiple possibilities, we return success but don't
23599 deduce anything. */
23602 {
23606 {
23611 /* Don't forget explicit template arguments in a pack. */
23615 }
23616 }
23621 }
23623 /* Core DR 115: In contexts where deduction is done and fails, or in
23624 contexts where deduction is not done, if a template argument list is
23625 specified and it, along with any default template arguments, identifies
23626 a single function template specialization, then the template-id is an
23627 lvalue for the function template specialization. */
23629 tree
23631 {
23644 {
23647 }
23649 {
23652 }
23654 {
23657 }
23660 {
23664 /* If we got some explicit template args, we need to plug them into
23665 the affected templates before we try to unify, in case the
23666 explicit args will completely resolve the templates in question. */
23674 {
23685 {
23688 {
23691 }
23694 {
23697 }
23698 }
23699 }
23701 {
23709 {
23710 tree base
23713 }
23717 }
23719 /* There were no good options and at least one bad one, so let the
23720 user know what the problem is. */
23722 }
23724 }
23726 /* As above, but error out if the expression remains overloaded. */
23728 tree
23730 {
23733 {
23737 }
23739 }
23741 /* Subroutine of resolve_overloaded_unification; does deduction for a single
23742 overload. Fills TARGS with any deduced arguments, or error_mark_node if
23743 different overloads deduce different arguments for a given parm.
23744 ADDR_P is true if the expression for which deduction is being
23745 performed was of the form "& fn" rather than simply "fn".
23747 Returns 1 on success. */
23749 static int
23751 tree orig_targs,
23752 tree targs,
23753 tree parm,
23754 tree arg,
23755 unification_kind_t strict,
23759 {
23761 tree tempargs;
23767 /* [temp.deduct.type] A template-argument can be deduced from a pointer
23768 to function or pointer to member function argument if the set of
23769 overloaded functions does not contain function templates and at most
23770 one of a set of overloaded functions provides a unique match.
23772 So if this is a template, just return success. */
23785 /* We don't copy orig_targs for this because if we have already deduced
23786 some template args from previous args, unify would complain when we
23787 try to deduce a template parameter for the same argument, even though
23788 there isn't really a conflict. */
23795 /* First make sure we didn't deduce anything that conflicts with
23796 explicitly specified args. */
23798 {
23805 /* Since we're unifying against ourselves, we will fill in
23806 template args used in the function parm list with our own
23807 template parms. Discard them. */
23810 {
23811 /* Check that the argument at each index of the deduced argument pack
23812 is equivalent to the corresponding explicitly specified argument.
23813 We may have deduced more arguments than were explicitly specified,
23814 and that's OK. */
23816 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
23817 that's wrong if we deduce the same argument pack from multiple
23818 function arguments: it's only incomplete the first time. */
23831 }
23834 }
23837 {
23842 }
23845 }
23847 /* PARM is a template class (perhaps with unbound template
23848 parameters). ARG is a fully instantiated type. If ARG can be
23849 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
23850 TARGS are as for unify. */
23852 static tree
23855 {
23864 /* We need to make a new template argument vector for the call to
23865 unify. If we used TARGS, we'd clutter it up with the result of
23866 the attempted unification, even if this class didn't work out.
23867 We also don't want to commit ourselves to all the unifications
23868 we've already done, since unification is supposed to be done on
23869 an argument-by-argument basis. In other words, consider the
23870 following pathological case:
23872 template <int I, int J, int K>
23873 struct S {};
23875 template <int I, int J>
23876 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
23878 template <int I, int J, int K>
23879 void f(S<I, J, K>, S<I, I, I>);
23881 void g() {
23882 S<0, 0, 0> s0;
23883 S<0, 1, 2> s2;
23885 f(s0, s2);
23886 }
23888 Now, by the time we consider the unification involving `s2', we
23889 already know that we must have `f<0, 0, 0>'. But, even though
23890 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
23891 because there are two ways to unify base classes of S<0, 1, 2>
23892 with S<I, I, I>. If we kept the already deduced knowledge, we
23893 would reject the possibility I=1. */
23901 else
23906 }
23908 /* Given a template type PARM and a class type ARG, find the unique
23909 base type in ARG that is an instance of PARM. We do not examine
23910 ARG itself; only its base-classes. If there is not exactly one
23911 appropriate base class, return NULL_TREE. PARM may be the type of
23912 a partial specialization, as well as a plain template type. Used
23913 by unify. */
23915 static enum template_base_result
23918 {
23920 tree binfo;
23926 {
23927 /* The type could not be completed. */
23930 }
23932 /* Walk in inheritance graph order. The search order is not
23933 important, and this avoids multiple walks of virtual bases. */
23935 {
23940 {
23941 /* If there is more than one satisfactory baseclass, then:
23943 [temp.deduct.call]
23945 If they yield more than one possible deduced A, the type
23946 deduction fails.
23948 applies. */
23950 {
23951 /* [temp.deduct.call]/4.3: If there is a class C that is a
23952 (direct or indirect) base class of D and derived (directly or
23953 indirectly) from a class B and that would be a valid deduced
23954 A, the deduced A cannot be B or pointer to B, respectively. */
23956 /* Ignore r. */
23960 else
23961 {
23964 }
23965 }
23968 }
23969 }
23973 }
23975 /* Returns the level of DECL, which declares a template parameter. */
23977 static int
23979 {
23981 {
23991 }
23993 }
23995 /* Decide whether ARG can be unified with PARM, considering only the
23996 cv-qualifiers of each type, given STRICT as documented for unify.
23997 Returns nonzero iff the unification is OK on that basis. */
23999 static int
24001 {
24007 {
24008 /* Although a CVR qualifier is ignored when being applied to a
24009 substituted template parameter ([8.3.2]/1 for example), that
24010 does not allow us to unify "const T" with "int&" because both
24011 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
24012 It is ok when we're allowing additional CV qualifiers
24013 at the outer level [14.8.2.1]/3,1st bullet. */
24022 }
24033 }
24035 /* Determines the LEVEL and INDEX for the template parameter PARM. */
24036 void
24038 {
24042 {
24045 }
24046 else
24047 {
24050 }
24051 }
24053 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
24054 do { \
24055 if (unify (TP, TA, P, A, S, EP)) \
24056 return 1; \
24057 } while (0)
24059 /* Unifies the remaining arguments in PACKED_ARGS with the pack
24060 expansion at the end of PACKED_PARMS. Returns 0 if the type
24061 deduction succeeds, 1 otherwise. STRICT is the same as in
24062 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
24063 function call argument list. We'll need to adjust the arguments to make them
24064 types. SUBR tells us if this is from a recursive call to
24065 type_unification_real, or for comparing two template argument
24066 lists. */
24068 static int
24072 {
24073 tree parm
24079 /* Add in any args remembered from an earlier partial instantiation. */
24087 /* Determine the parameter packs we will be deducing from the
24088 pattern, and record their current deductions. */
24091 {
24095 /* Only template parameter packs can be deduced, not e.g. function
24096 parameter packs or __bases or __integer_pack. */
24100 /* Determine the index and level of this parameter pack. */
24105 /* Keep track of the parameter packs and their corresponding
24106 argument packs. */
24109 }
24111 /* Loop through all of the arguments that have not yet been
24112 unified and unify each with the pattern. */
24114 {
24115 tree parm;
24119 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
24120 or the element of its argument pack at the current index if
24121 this argument was explicitly specified. */
24123 {
24132 {
24135 }
24137 }
24139 /* If we had explicit template arguments, substitute them into the
24140 pattern before deduction. */
24142 {
24143 /* Some arguments might still be unspecified or dependent. */
24151 NULL_TREE);
24156 }
24157 else
24160 /* Unify the pattern with the current argument. */
24162 explain_p))
24165 /* For each parameter pack, collect the deduced value. */
24167 {
24173 }
24174 }
24176 /* Verify that the results of unification with the parameter packs
24177 produce results consistent with what we've seen before, and make
24178 the deduced argument packs available. */
24180 {
24187 /* By default keep the original deduced argument pack.
24188 If necessary, more specific code is going to update the
24189 resulting deduced argument later down in this function. */
24193 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
24194 actually deduce anything. */
24202 {
24203 /* If we had fewer function args than explicit template args,
24204 just use the explicits. */
24209 }
24212 {
24213 tree result;
24214 /* Build the deduced *_ARGUMENT_PACK. */
24216 {
24219 }
24220 else
24225 /* Note the deduced argument packs for this parameter
24226 pack. */
24228 }
24232 {
24233 /* We only had the explicitly-provided arguments before, but
24234 now we have a complete set of arguments. */
24240 }
24241 else
24242 {
24246 /* During template argument deduction for the aggregate deduction
24247 candidate, the number of elements in a trailing parameter pack
24248 is only deduced from the number of remaining function
24249 arguments if it is not otherwise deduced. */
24252 /* FIXME This isn't set properly for partial instantiations. */
24258 /* Inconsistent unification of this parameter pack. */
24260 bad_old_arg,
24261 bad_new_arg);
24262 }
24263 }
24266 }
24268 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
24269 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
24270 parameters and return value are as for unify. */
24272 static int
24276 {
24277 tree parm_max;
24278 tree arg_max;
24282 /* Our representation of array types uses "N - 1" as the
24283 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
24284 not an integer constant. We cannot unify arbitrarily
24285 complex expressions, so we eliminate the MINUS_EXPRs
24286 here. */
24290 {
24293 }
24297 {
24298 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
24299 trying to unify the type of a variable with the type
24300 of a template parameter. For example:
24302 template <unsigned int N>
24303 void f (char (&) [N]);
24304 int g();
24305 void h(int i) {
24306 char a[g(i)];
24307 f(a);
24308 }
24310 Here, the type of the ARG will be "int [g(i)]", and
24311 may be a SAVE_EXPR, etc. */
24315 }
24317 /* If only one of the bounds used a MINUS_EXPR, compensate
24318 by adding one to the other bound. */
24321 integer_type_node,
24322 parm_max,
24323 integer_one_node);
24326 integer_type_node,
24327 arg_max,
24328 integer_one_node);
24332 }
24334 /* Returns whether T, a P or A in unify, is a type, template or expression. */
24338 static pa_kind_t
24340 {
24349 else
24351 }
24353 /* Deduce the value of template parameters. TPARMS is the (innermost)
24354 set of template parameters to a template. TARGS is the bindings
24355 for those template parameters, as determined thus far; TARGS may
24356 include template arguments for outer levels of template parameters
24357 as well. PARM is a parameter to a template function, or a
24358 subcomponent of that parameter; ARG is the corresponding argument.
24359 This function attempts to match PARM with ARG in a manner
24360 consistent with the existing assignments in TARGS. If more values
24361 are deduced, then TARGS is updated.
24363 Returns 0 if the type deduction succeeds, 1 otherwise. The
24364 parameter STRICT is a bitwise or of the following flags:
24366 UNIFY_ALLOW_NONE:
24367 Require an exact match between PARM and ARG.
24368 UNIFY_ALLOW_MORE_CV_QUAL:
24369 Allow the deduced ARG to be more cv-qualified (by qualification
24370 conversion) than ARG.
24371 UNIFY_ALLOW_LESS_CV_QUAL:
24372 Allow the deduced ARG to be less cv-qualified than ARG.
24373 UNIFY_ALLOW_DERIVED:
24374 Allow the deduced ARG to be a template base class of ARG,
24375 or a pointer to a template base class of the type pointed to by
24376 ARG.
24377 UNIFY_ALLOW_INTEGER:
24378 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
24379 case for more information.
24380 UNIFY_ALLOW_OUTER_LEVEL:
24381 This is the outermost level of a deduction. Used to determine validity
24382 of qualification conversions. A valid qualification conversion must
24383 have const qualified pointers leading up to the inner type which
24384 requires additional CV quals, except at the outer level, where const
24385 is not required [conv.qual]. It would be normal to set this flag in
24386 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
24387 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
24388 This is the outermost level of a deduction, and PARM can be more CV
24389 qualified at this point.
24390 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
24391 This is the outermost level of a deduction, and PARM can be less CV
24392 qualified at this point. */
24394 static int
24397 {
24399 tree targ;
24400 tree tparm;
24402 tsubst_flags_t complain = (explain_p
24403 ? tf_warning_or_error
24406 /* I don't think this will do the right thing with respect to types.
24407 But the only case I've seen it in so far has been array bounds, where
24408 signedness is the only information lost, and I think that will be
24409 okay. VIEW_CONVERT_EXPR can appear with class NTTP, thanks to
24410 finish_id_expression_1, and are also OK. */
24418 /* We can't deduce anything from this, but we might get all the
24419 template args from other function args. */
24425 /* If PARM uses template parameters, then we can't bail out here,
24426 even if ARG == PARM, since we won't record unifications for the
24427 template parameters. We might need them if we're trying to
24428 figure out which of two things is more specialized. */
24432 /* Handle init lists early, so the rest of the function can assume
24433 we're dealing with a type. */
24435 {
24436 tree elttype;
24441 /* We can only deduce from an initializer list argument if the
24442 parameter is std::initializer_list or an array; otherwise this
24443 is a non-deduced context. */
24448 else
24449 {
24451 /* Deduction is defined in terms of a single type, so just punt
24452 on the (bizarre) std::initializer_list<T...>. */
24455 }
24460 /* If ELTTYPE has no deducible template parms, skip deduction from
24462 else
24464 {
24472 {
24476 /* It should only be possible to get here for a call. */
24478 elt_strict |= maybe_adjust_types_for_deduction
24481 }
24484 explain_p);
24485 }
24489 {
24490 /* Also deduce from the length of the initializer list. */
24497 }
24499 /* If the std::initializer_list<T> deduction worked, replace the
24500 deduced A with std::initializer_list<A>. */
24502 {
24507 }
24509 }
24511 /* If parm and arg aren't the same kind of thing (template, type, or
24512 expression), fail early. */
24516 /* Immediately reject some pairs that won't unify because of
24517 cv-qualification mismatches. */
24520 /* It is the elements of the array which hold the cv quals of an array
24521 type, and the elements might be template type parms. We'll check
24522 when we recurse. */
24524 /* We check the cv-qualifiers when unifying with template type
24525 parameters below. We want to allow ARG `const T' to unify with
24526 PARM `T' for example, when computing which of two templates
24527 is more specialized, for example. */
24536 /* PMFs recurse at the same level, so don't strip this yet. */
24544 {
24548 /* In a type which contains a nested-name-specifier, template
24549 argument values cannot be deduced for template parameters used
24550 within the nested-name-specifier. */
24562 /* The PARM is not one we're trying to unify. Just check
24563 to see if it matches ARG. */
24564 {
24569 else
24571 }
24578 /* Check for mixed types and values. */
24586 {
24589 {
24590 /* First try to match ARG directly. */
24592 explain_p);
24594 {
24595 /* Otherwise, look for a suitable base of ARG, as below. */
24602 }
24603 }
24604 /* ARG must be constructed from a template class or a template
24605 template parameter. */
24610 /* Deduce arguments T, i from TT<T> or TT<i>. */
24616 /* If the template is a template template parameter, use the
24617 TEMPLATE_TEMPLATE_PARM for matching. */
24620 /* Fall through to deduce template name. */
24621 }
24625 {
24626 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
24628 /* Simple cases: Value already set, does match or doesn't. */
24633 }
24634 else
24635 {
24636 /* If PARM is `const T' and ARG is only `int', we don't have
24637 a match unless we are allowing additional qualification.
24638 If ARG is `const int' and PARM is just `T' that's OK;
24639 that binds `const int' to `T'. */
24644 /* Consider the case where ARG is `const volatile int' and
24645 PARM is `const T'. Then, T should be `volatile int'. */
24646 arg = cp_build_qualified_type
24651 /* Simple cases: Value already set, does match or doesn't. */
24657 /* Make sure that ARG is not a variable-sized array. (Note
24658 that were talking about variable-sized arrays (like
24659 `int[n]'), rather than arrays of unknown size (like
24660 `int[]').) We'll get very confused by such a type since
24661 the bound of the array is not constant, and therefore
24662 not mangleable. Besides, such types are not allowed in
24663 ISO C++, so we can do as we please here. We do allow
24664 them for 'auto' deduction, since that isn't ABI-exposed. */
24668 /* Strip typedefs as in convert_template_argument. */
24670 }
24672 /* If ARG is a parameter pack or an expansion, we cannot unify
24673 against it unless PARM is also a parameter pack. */
24678 /* If the argument deduction results is a METHOD_TYPE,
24679 then there is a problem.
24680 METHOD_TYPE doesn't map to any real C++ type the result of
24681 the deduction cannot be of that type. */
24695 {
24696 /* The PARM is not one we're trying to unify. Just check
24697 to see if it matches ARG. */
24703 }
24709 {
24713 /* We're deducing from an array bound, the type doesn't matter.
24714 This conversion should match the one below. */
24720 }
24722 /* [temp.deduct.type] If, in the declaration of a function template
24723 with a non-type template-parameter, the non-type
24724 template-parameter is used in an expression in the function
24725 parameter-list and, if the corresponding template-argument is
24726 deduced, the template-argument type shall match the type of the
24727 template-parameter exactly, except that a template-argument
24728 deduced from an array bound may be of any integral type.
24729 The non-type parameter might use already deduced type parameters. */
24732 /* We don't have enough levels of args to do any substitution. This
24734 else
24735 {
24741 {
24744 LOOKUP_NORMAL,
24748 }
24749 }
24753 /* Template-parameter dependent expression. Just accept it for now.
24754 It will later be processed in convert_template_argument. */
24755 ;
24759 /* OK. Ignore top-level quals here because a class-type template
24763 /* Convert the ARG to the type of PARM; the deduced non-type
24764 template argument must exactly match the types of the
24765 corresponding parameter. This conversion should match the
24766 one above. */
24769 {
24770 /* We haven't deduced the type of this parameter yet. */
24772 /* We deduce from array bounds in try_array_deduction. */
24775 {
24776 /* Deduce it from the non-type argument. As above, ignore
24777 top-level quals here too. */
24782 /* Now check whether the type of this parameter is still
24783 dependent, and give up if so. */
24789 }
24790 else
24791 /* Try again later. */
24793 }
24794 else
24797 /* If ARG is a parameter pack or an expansion, we cannot unify
24798 against it unless PARM is also a parameter pack. */
24803 {
24806 }
24811 {
24812 /* A pointer-to-member constant can be unified only with
24813 another constant. */
24817 /* Just unify the class member. It would be useless (and possibly
24818 wrong, depending on the strict flags) to unify also
24819 PTRMEM_CST_CLASS, because we want to be sure that both parm and
24820 arg refer to the same variable, even if through different
24821 classes. For instance:
24823 struct A { int x; };
24824 struct B : A { };
24826 Unification of &A::x and &B::x must succeed. */
24829 }
24832 {
24836 /* [temp.deduct.call]
24838 A can be another pointer or pointer to member type that can
24839 be converted to the deduced A via a qualification
24840 conversion (_conv.qual_).
24842 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
24843 This will allow for additional cv-qualification of the
24844 pointed-to types if appropriate. */
24847 /* The derived-to-base conversion only persists through one
24848 level of pointers. */
24853 }
24886 /* We have already checked cv-qualification at the top of the
24887 function. */
24891 /* As far as unification is concerned, this wins. Later checks
24892 will invalidate it if necessary. */
24895 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
24896 /* Type INTEGER_CST can come from ordinary constant template args. */
24908 {
24918 /* Check for pack expansions in the parameters. */
24920 {
24922 {
24924 /* We can unify against something with a trailing
24925 parameter pack. */
24927 else
24928 /* [temp.deduct.type]/9: If the template argument list of
24929 P contains a pack expansion that is not the last
24930 template argument, the entire template argument list
24931 is a non-deduced context. */
24933 }
24934 }
24936 /* If we don't have enough arguments to satisfy the parameters
24937 (not counting the pack expression at the end), or we have
24938 too many arguments for a parameter list that doesn't end in
24939 a pack expression, we can't unify. */
24945 /* Unify all of the parameters that precede the (optional)
24946 pack expression. */
24948 {
24953 }
24956 DEDUCE_EXACT,
24959 }
24967 {
24975 }
24980 {
24984 {
24985 /* First, we try to unify the PARM and ARG directly. */
24990 {
24991 /* Fallback to the special case allowed in
24992 [temp.deduct.call]:
24994 If P is a class, and P has the form
24995 template-id, then A can be a derived class of
24996 the deduced A. Likewise, if P is a pointer to
24997 a class of the form template-id, A can be a
24998 pointer to a derived class pointed to by the
24999 deduced A. */
25005 {
25006 /* Don't give the derived diagnostic if we're
25007 already dealing with the same template. */
25008 bool same_template
25014 }
25015 }
25016 }
25020 /* Perhaps PARM is something like S<U> and ARG is S<int>.
25021 Then, we should unify `int' and `U'. */
25023 else
25024 /* There's no chance of unification succeeding. */
25029 }
25036 {
25039 tree a;
25045 /* CV qualifications for methods can never be deduced, they must
25046 match exactly. We need to check them explicitly here,
25047 because type_unification_real treats them as any other
25048 cv-qualified parameter. */
25050 && (!check_cv_quals_for_unify
25078 {
25088 else
25089 {
25092 /* Here "less cv-qual" means the deduced arg (i.e. parm) has
25093 /more/ noexcept, since function pointer conversions are the
25094 reverse of qualification conversions. */
25099 else
25101 }
25102 }
25104 {
25105 /* As for noexcept. */
25112 else
25114 }
25117 }
25120 /* Unify a pointer to member with a pointer to member function, which
25121 deduces the type of the member as a function type. */
25123 {
25124 /* Check top-level cv qualifiers */
25132 /* Determine the type of the function we are unifying against. */
25136 }
25155 /* Matched cases are handled by the ARG == PARM test above. */
25159 /* We might get a variable as a non-type template argument in parm if the
25160 corresponding parameter is type-dependent. Make any necessary
25161 adjustments based on whether arg is a reference. */
25165 {
25170 }
25171 /* Now use the normal expression code to check whether they match. */
25182 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
25183 or TRAIT_TYPE nodes. */
25187 /* Unification fails if we hit an error node. */
25192 {
25202 }
25203 /* FALLTHRU */
25206 /* An unresolved overload is a nondeduced context. */
25212 expr:
25213 /* We must be looking at an expression. This can happen with
25214 something like:
25216 template <int I>
25217 void foo(S<I>, S<I + 2>);
25219 or
25221 template<typename T>
25222 void foo(A<T, T{}>);
25224 This is a "non-deduced context":
25226 [deduct.type]
25228 The non-deduced contexts are:
25230 --A non-type template argument or an array bound in which
25231 a subexpression references a template parameter.
25233 In these cases, we assume deduction succeeded, but don't
25234 actually infer any unifications. */
25239 else
25241 }
25242 }
25243 #undef RECUR_AND_CHECK_FAILURE
25244 \f
25245 /* Note that DECL can be defined in this translation unit, if
25246 required. */
25248 static void
25250 {
25251 tree clone;
25255 }
25257 /* Called if RESULT is explicitly instantiated, or is a member of an
25258 explicitly instantiated class. */
25260 void
25262 {
25265 /* If this entity has already been written out, it's too late to
25266 make any modifications. */
25270 /* consteval functions are never emitted. */
25275 /* For anonymous namespace we don't need to do anything. */
25277 {
25280 }
25283 /* The TREE_PUBLIC flag for function declarations will have been
25284 set correctly by tsubst. */
25288 {
25291 }
25292 else
25293 {
25296 /* Always make artificials weak. */
25299 /* For WIN32 we also want to put explicit instantiations in
25300 linkonce sections. */
25305 /* If the function has already been instantiated, clear DECL_EXTERNAL,
25306 since start_preparsed_function wouldn't have if we had an earlier
25307 extern explicit instantiation. */
25309 }
25311 /* If EXTERN_P, then this function will not be emitted -- unless
25312 followed by an explicit instantiation, at which point its linkage
25313 will be adjusted. If !EXTERN_P, then this function will be
25314 emitted here. In neither circumstance do we want
25315 import_export_decl to adjust the linkage. */
25317 }
25319 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
25320 important template arguments. If any are missing, we check whether
25321 they're important by using error_mark_node for substituting into any
25322 args that were used for partial ordering (the ones between ARGS and END)
25323 and seeing if it bubbles up. */
25325 static bool
25327 {
25331 {
25334 }
25336 {
25340 }
25342 }
25344 /* Given two function templates PAT1 and PAT2, return:
25346 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
25347 -1 if PAT2 is more specialized than PAT1.
25348 0 if neither is more specialized.
25350 LEN indicates the number of parameters we should consider
25351 (defaulted parameters should not be considered).
25353 The 1998 std underspecified function template partial ordering, and
25354 DR214 addresses the issue. We take pairs of arguments, one from
25355 each of the templates, and deduce them against each other. One of
25356 the templates will be more specialized if all the *other*
25357 template's arguments deduce against its arguments and at least one
25358 of its arguments *does* *not* deduce against the other template's
25359 corresponding argument. Deduction is done as for class templates.
25360 The arguments used in deduction have reference and top level cv
25361 qualifiers removed. Iff both arguments were originally reference
25362 types *and* deduction succeeds in both directions, an lvalue reference
25363 wins against an rvalue reference and otherwise the template
25364 with the more cv-qualified argument wins for that pairing (if
25365 neither is more cv-qualified, they both are equal). Unlike regular
25366 deduction, after all the arguments have been deduced in this way,
25367 we do *not* verify the deduced template argument values can be
25368 substituted into non-deduced contexts.
25370 The logic can be a bit confusing here, because we look at deduce1 and
25371 targs1 to see if pat2 is at least as specialized, and vice versa; if we
25372 can find template arguments for pat1 to make arg1 look like arg2, that
25373 means that arg2 is at least as specialized as arg1. */
25375 int
25377 {
25390 /* Remove the this parameter from non-static member functions. If
25391 one is a non-static member function and the other is not a static
25392 member function, remove the first parameter from that function
25393 also. This situation occurs for operator functions where we
25394 locate both a member function (with this pointer) and non-member
25395 operator (with explicit first operand). */
25397 {
25402 }
25404 {
25407 {
25408 len--;
25410 }
25411 }
25413 /* If only one is a conversion operator, they are unordered. */
25417 /* Consider the return type for a conversion function */
25419 {
25422 len++;
25423 }
25425 processing_template_decl++;
25431 /* Stop when an ellipsis is seen. */
25433 {
25444 {
25445 /* When both arguments are pack expansions, we need only
25446 unify the patterns themselves. */
25450 /* This is the last comparison we need to do. */
25452 }
25455 {
25459 }
25462 {
25466 }
25472 {
25478 /* Setup the parameter vector, which contains only ARG1. */
25481 /* Setup the argument vector, which contains the remaining
25482 arguments. */
25491 /* We cannot deduce in the other direction, because ARG1 is
25492 a pack expansion but ARG2 is not. */
25494 }
25496 {
25502 /* Setup the parameter vector, which contains only ARG1. */
25505 /* Setup the argument vector, which contains the remaining
25506 arguments. */
25515 /* We cannot deduce in the other direction, because ARG2 is
25516 a pack expansion but ARG1 is not.*/
25518 }
25520 else
25521 {
25522 /* The normal case, where neither argument is a pack
25523 expansion. */
25530 }
25532 /* If we couldn't deduce arguments for tparms1 to make arg1 match
25533 arg2, then arg2 is not as specialized as arg1. */
25539 /* "If, for a given type, deduction succeeds in both directions
25540 (i.e., the types are identical after the transformations above)
25541 and both P and A were reference types (before being replaced with
25542 the type referred to above):
25543 - if the type from the argument template was an lvalue reference and
25544 the type from the parameter template was not, the argument type is
25545 considered to be more specialized than the other; otherwise,
25546 - if the type from the argument template is more cv-qualified
25547 than the type from the parameter template (as described above),
25548 the argument type is considered to be more specialized than the other;
25549 otherwise,
25550 - neither type is more specialized than the other." */
25553 {
25555 {
25558 else
25560 }
25562 {
25567 }
25568 }
25571 /* We've failed to deduce something in either direction.
25572 These must be unordered. */
25577 /* We have already processed all of the arguments in our
25578 handing of the pack expansion type. */
25583 }
25585 /* "In most cases, all template parameters must have values in order for
25586 deduction to succeed, but for partial ordering purposes a template
25587 parameter may remain without a value provided it is not used in the
25588 types being used for partial ordering."
25590 Thus, if we are missing any of the targs1 we need to substitute into
25591 origs1, then pat2 is not as specialized as pat1. This can happen when
25592 there is a nondeduced context. */
25598 processing_template_decl--;
25600 /* If both deductions succeed, the partial ordering selects the more
25601 constrained template. */
25602 /* P2113: If the corresponding template-parameters of the
25603 template-parameter-lists are not equivalent ([temp.over.link]) or if
25604 the function parameters that positionally correspond between the two
25605 templates are not of the same type, neither template is more
25606 specialized than the other. */
25611 {
25617 }
25619 /* All things being equal, if the next argument is a pack expansion
25620 for one function but not for the other, prefer the
25621 non-variadic function. FIXME this is bogus; see c++/41958. */
25625 {
25628 }
25634 else
25636 }
25638 /* Determine which of two partial specializations of TMPL is more
25639 specialized.
25641 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
25642 to the first partial specialization. The TREE_PURPOSE is the
25643 innermost set of template parameters for the partial
25644 specialization. PAT2 is similar, but for the second template.
25646 Return 1 if the first partial specialization is more specialized;
25647 -1 if the second is more specialized; 0 if neither is more
25648 specialized.
25650 See [temp.class.order] for information about determining which of
25651 two templates is more specialized. */
25653 static int
25655 {
25656 tree targs;
25665 /* Just like what happens for functions, if we are ordering between
25666 different template specializations, we may encounter dependent
25667 types in the arguments, and we need our dependency check functions
25668 to behave correctly. */
25672 {
25675 }
25679 {
25682 }
25685 /* If both deductions succeed, the partial ordering selects the more
25686 constrained template. */
25690 /* In the case of a tie where at least one of the templates
25691 has a parameter pack at the end, the template with the most
25692 non-packed parameters wins. */
25694 && any_deductions
25697 {
25703 /* We don't count the pack expansion at the end. */
25713 }
25716 }
25718 /* Return the template arguments that will produce the function signature
25719 DECL from the function template FN, with the explicit template
25720 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
25721 also match. Return NULL_TREE if no satisfactory arguments could be
25722 found. */
25724 static tree
25726 {
25730 tree decl_arg_types;
25733 tree arg;
25737 /* Never do unification on the 'this' parameter. */
25759 }
25761 /* Return the innermost template arguments that, when applied to a partial
25762 specialization SPEC_TMPL of TMPL, yield the ARGS.
25764 For example, suppose we have:
25766 template <class T, class U> struct S {};
25767 template <class T> struct S<T*, int> {};
25769 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
25770 partial specialization and the ARGS will be {double*, int}. The resulting
25771 vector will be {double}, indicating that `T' is bound to `double'. */
25773 static tree
25775 {
25777 tree spec_args
25780 tree deduced_args;
25781 tree innermost_deduced_args;
25785 {
25789 innermost_deduced_args);
25790 }
25791 else
25795 again:
25804 {
25806 {
25812 }
25814 }
25817 {
25820 }
25822 /* Verify that nondeduced template arguments agree with the type
25823 obtained from argument deduction.
25825 For example:
25827 struct A { typedef int X; };
25828 template <class T, class U> struct C {};
25829 template <class T> struct C<T, typename T::X> {};
25831 Then with the instantiation `C<A, int>', we can deduce that
25832 `T' is `A' but unify () does not check whether `typename T::X'
25833 is `int'. */
25844 /* We only need to check the innermost arguments; the other
25845 arguments will always agree. */
25850 /* Now that we have bindings for all of the template arguments,
25851 ensure that the arguments deduced for the template template
25852 parameters have compatible template parameter lists. See the use
25853 of template_template_parm_bindings_ok_p in fn_type_unification
25854 for more information. */
25859 }
25861 // Compare two function templates T1 and T2 by deducing bindings
25862 // from one against the other. If both deductions succeed, compare
25863 // constraints to see which is more constrained.
25864 static int
25866 {
25871 {
25874 }
25877 {
25880 }
25882 // If both deductions succeed, then one may be more constrained.
25887 }
25889 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
25890 Return the TREE_LIST node with the most specialized template, if
25891 any. If there is no most specialized template, the error_mark_node
25892 is returned.
25894 Note that this function does not look at, or modify, the
25895 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
25896 returned is one of the elements of INSTANTIATIONS, callers may
25897 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
25898 and retrieve it from the value returned. */
25900 tree
25902 {
25909 {
25915 {
25916 /* Equally specialized, move to next function. If there
25917 is no next function, nothing's most specialized. */
25922 }
25923 }
25926 /* Now verify that champ is better than everything earlier in the
25927 instantiation list. */
25930 {
25933 }
25934 }
25936 processing_template_decl--;
25942 }
25944 /* If DECL is a specialization of some template, return the most
25945 general such template. Otherwise, returns NULL_TREE.
25947 For example, given:
25949 template <class T> struct S { template <class U> void f(U); };
25951 if TMPL is `template <class U> void S<int>::f(U)' this will return
25952 the full template. This function will not trace past partial
25953 specializations, however. For example, given in addition:
25955 template <class T> struct S<T*> { template <class U> void f(U); };
25957 if TMPL is `template <class U> void S<int*>::f(U)' this will return
25958 `template <class T> template <class U> S<T*>::f(U)'. */
25960 tree
25962 {
25964 {
25967 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
25968 template friend, or a FIELD_DECL for a capture pack. */
25971 }
25973 /* Look for more and more general templates. */
25975 {
25976 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
25977 (See cp-tree.h for details.) */
25986 /* Stop if we run into an explicitly specialized class template. */
25993 }
25996 }
25998 /* Return the most specialized of the template partial specializations
25999 which can produce TARGET, a specialization of some class or variable
26000 template. The value returned is a TEMPLATE_INFO; the TI_TEMPLATE is a
26001 TEMPLATE_DECL node corresponding to the partial specialization, while
26002 the TI_ARGS is the set of template arguments that must be substituted
26003 into the template pattern in order to generate TARGET. The result is
26004 cached in the TI_PARTIAL_INFO of the corresponding TEMPLATE_INFO unless
26005 RECHECKING is true.
26007 If the choice of partial specialization is ambiguous, a diagnostic
26008 is issued, and the error_mark_node is returned. If there are no
26009 partial specializations matching TARGET, then NULL_TREE is
26010 returned, indicating that the primary template should be used. */
26012 tree
26015 {
26019 {
26024 }
26026 {
26030 }
26032 {
26037 }
26038 else
26045 && tinfo
26052 /* There are no partial specializations of this template. */
26058 /* For determining which partial specialization to use, only the
26059 innermost args are interesting. */
26062 {
26065 }
26067 /* The caller hasn't called push_to_top_level yet, but we need
26068 get_partial_spec_bindings to be done in non-template context so that we'll
26069 fully resolve everything. */
26070 processing_template_decl_sentinel ptds;
26074 {
26077 tree spec_tmpl;
26079 {
26080 /* Substitute in the template args from the enclosing class. */
26086 }
26087 else
26092 {
26096 /* Keep the candidate only if its constraints are satisfied. */
26099 }
26100 }
26108 {
26111 ;
26112 else
26113 {
26115 {
26118 {
26121 }
26122 }
26124 }
26125 }
26129 {
26132 {
26135 }
26136 }
26139 {
26146 else
26150 {
26155 }
26158 }
26164 }
26166 /* Explicitly instantiate DECL. */
26168 void
26170 {
26175 /* An error occurred, for which grokdeclarator has already issued
26176 an appropriate message. */
26179 {
26182 }
26184 {
26187 else
26190 }
26196 {
26197 /* There is an asymmetry here in the way VAR_DECLs and
26198 FUNCTION_DECLs are handled by grokdeclarator. In the case of
26199 the latter, the DECL we get back will be marked as a
26200 template instantiation, and the appropriate
26201 DECL_TEMPLATE_INFO will be set up. This does not happen for
26202 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
26203 should handle VAR_DECLs as it currently handles
26204 FUNCTION_DECLs. */
26206 {
26209 }
26212 {
26215 }
26217 {
26222 }
26223 }
26225 {
26228 }
26229 else
26232 /* Check for various error cases. Note that if the explicit
26233 instantiation is valid the RESULT will currently be marked as an
26234 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
26235 until we get here. */
26238 {
26239 /* DR 259 [temp.spec].
26241 Both an explicit instantiation and a declaration of an explicit
26242 specialization shall not appear in a program unless the explicit
26243 instantiation follows a declaration of the explicit specialization.
26245 For a given set of template parameters, if an explicit
26246 instantiation of a template appears after a declaration of an
26247 explicit specialization for that template, the explicit
26248 instantiation has no effect. */
26250 }
26252 {
26253 /* [temp.spec]
26255 No program shall explicitly instantiate any template more
26256 than once.
26258 We check DECL_NOT_REALLY_EXTERN so as not to complain when
26259 the first instantiation was `extern' and the second is not,
26260 and EXTERN_P for the opposite case. */
26263 /* If an "extern" explicit instantiation follows an ordinary
26264 explicit instantiation, the template is instantiated. */
26267 }
26269 {
26272 }
26274 {
26277 }
26280 ;
26282 {
26285 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
26288 }
26289 else
26297 }
26299 static void
26301 {
26307 {
26310 }
26311 }
26313 /* Perform an explicit instantiation of template class T. STORAGE, if
26314 non-null, is the RID for extern, inline or static. COMPLAIN is
26315 nonzero if this is called from the parser, zero if called recursively,
26316 since the standard is unclear (as detailed below). */
26318 void
26320 {
26322 {
26326 else
26329 }
26334 {
26337 t);
26339 }
26341 /* At most one of these will be true. */
26347 {
26349 {
26352 "ISO C++ 1998 forbids the use of %<extern%> on "
26354 }
26355 else
26357 "ISO C++ forbids the use of %qE"
26366 else
26368 storage);
26369 }
26372 /* DR 259 [temp.spec].
26374 Both an explicit instantiation and a declaration of an explicit
26375 specialization shall not appear in a program unless the
26376 explicit instantiation follows a declaration of the explicit
26377 specialization.
26379 For a given set of template parameters, if an explicit
26380 instantiation of a template appears after a declaration of an
26381 explicit specialization for that template, the explicit
26382 instantiation has no effect. */
26386 {
26387 /* We've already instantiated the template. */
26389 /* [temp.spec]
26391 No program shall explicitly instantiate any template more
26392 than once.
26394 If EXTERN_P then this is ok. */
26400 }
26408 /* In contrast to implicit instantiation, where only the
26409 declarations, and not the definitions, of members are
26410 instantiated, we have here:
26412 [temp.explicit]
26414 An explicit instantiation that names a class template
26415 specialization is also an explicit instantiation of the same
26416 kind (declaration or definition) of each of its members (not
26417 including members inherited from base classes and members
26418 that are templates) that has not been previously explicitly
26419 specialized in the translation unit containing the explicit
26420 instantiation, provided that the associated constraints, if
26421 any, of that member are satisfied by the template arguments
26422 of the explicit instantiation. */
26426 && !static_p
26430 {
26435 }
26437 {
26443 }
26444 }
26446 /* Given a function DECL, which is a specialization of TMPL, modify
26447 DECL to be a re-instantiation of TMPL with the same template
26448 arguments. TMPL should be the template into which tsubst'ing
26449 should occur for DECL, not the most general template.
26451 One reason for doing this is a scenario like this:
26453 template <class T>
26454 void f(const T&, int i);
26456 void g() { f(3, 7); }
26458 template <class T>
26459 void f(const T& t, const int i) { }
26461 Note that when the template is first instantiated, with
26462 instantiate_template, the resulting DECL will have no name for the
26463 first parameter, and the wrong type for the second. So, when we go
26464 to instantiate the DECL, we regenerate it. */
26466 static void
26468 {
26469 /* The arguments used to instantiate DECL, from the most general
26470 template. */
26473 /* Make sure that we can see identifiers, and compute access correctly. */
26477 {
26478 tree specs;
26482 /* Don't bother with this for unique friends that can't be redeclared and
26483 might change type if regenerated (PR69836). */
26487 /* Use the source location of the definition. */
26495 /* Instantiate a dynamic exception-specification. noexcept will be
26496 handled below. */
26499 {
26505 specs);
26506 }
26508 /* Merge parameter declarations. */
26512 {
26519 }
26522 {
26523 /* If we're regenerating a specialization, the contracts will have
26524 been copied from the most general template. Replace those with
26525 the ones from the actual specialization. */
26528 {
26531 }
26534 }
26536 /* Merge additional specifiers from the CODE_PATTERN. */
26542 }
26544 {
26553 }
26554 else
26557 done:
26559 }
26561 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
26562 substituted to get DECL. */
26564 tree
26566 {
26569 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
26570 for the instantiation. This is not always the most general
26571 template. Consider, for example:
26573 template <class T>
26574 struct S { template <class U> void f();
26575 template <> void f<int>(); };
26577 and an instantiation of S<double>::f<int>. We want TD to be the
26578 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
26580 more general template. */
26582 /* We must also deal with friend templates. Given:
26584 template <class T> struct S {
26585 template <class U> friend void f() {};
26586 };
26588 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
26589 so far as the language is concerned, but that's still
26590 where we get the pattern for the instantiation from. On
26591 other hand, if the definition comes outside the class, say:
26593 template <class T> struct S {
26594 template <class U> friend void f();
26595 };
26596 template <class U> friend void f() {}
26598 we don't need to look any further. That's what the check for
26599 DECL_INITIAL is for. */
26603 {
26604 /* The present template, TD, should not be a definition. If it
26605 were a definition, we should be using it! Note that we
26606 cannot restructure the loop to just keep going until we find
26607 a template with a definition, since that might go too far if
26608 a specialization was declared, but not defined. */
26610 /* Fetch the more general template. */
26612 }
26615 }
26617 /* Returns true if we need to instantiate this template instance even if we
26618 know we aren't going to emit it. */
26620 bool
26622 {
26623 /* We always instantiate inline functions so that we can inline them. An
26624 explicit instantiation declaration prohibits implicit instantiation of
26625 non-inline functions. With high levels of optimization, we would
26626 normally inline non-inline functions -- but we're not allowed to do
26627 that for "extern template" functions. Therefore, we check
26628 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
26632 /* And we need to instantiate static data members so that
26633 their initializers are available in integral constant
26634 expressions. */
26637 }
26639 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
26640 instantiate it now, modifying TREE_TYPE (fn). Returns false on
26641 error, true otherwise. */
26643 bool
26645 {
26649 /* Don't instantiate a noexcept-specification from template context. */
26659 {
26661 /* We're in start_preparsed_function, keep going. */
26668 }
26679 /* For a member friend template we can get a TEMPLATE_DECL. Let's use
26680 its FUNCTION_DECL for the rest of this function -- push_access_scope
26681 doesn't accept TEMPLATE_DECLs. */
26683 {
26686 }
26689 {
26694 }
26696 {
26700 {
26703 /* This might have failed because of an unparsed DMI, so
26704 let's try again later. */
26706 }
26708 {
26709 /* If hash_set::add returns true, the element was already there. */
26714 fn);
26716 }
26718 {
26726 {
26727 /* If needed, set current_class_ptr for the benefit of
26728 tsubst_copy/PARM_DECL. */
26733 }
26735 /* If this function is represented by a TEMPLATE_DECL, then
26736 the deferred noexcept-specification might still contain
26737 dependent types, even after substitution. And we need the
26738 dependency check functions to work in build_noexcept_spec. */
26742 /* Do deferred instantiation of the noexcept-specifier. */
26747 /* Build up the noexcept-specification. */
26757 }
26758 else
26763 }
26766 {
26767 /* This failed with a hard error, so let's go with false. */
26770 }
26777 }
26779 /* We're starting to process the function INST, an instantiation of PATTERN;
26780 add their parameters to local_specializations. */
26782 void
26784 {
26788 {
26792 }
26794 {
26796 {
26799 }
26800 else
26801 {
26802 /* Register the (value) argument pack as a specialization of
26803 TMPL_PARM, then move on. */
26806 }
26807 }
26809 }
26811 /* Instantiate the body of D using PATTERN with ARGS. We have
26812 already determined PATTERN is the correct template to use.
26813 NESTED_P is true if this is a nested function, in which case
26814 PATTERN will be a FUNCTION_DECL not a TEMPLATE_DECL. */
26816 static void
26818 {
26823 {
26826 }
26827 else
26828 /* Only OMP reductions are nested. */
26840 {
26841 /* The variable might be a lambda's extra scope, and that
26842 lambda's visibility depends on D's. */
26845 }
26847 /* Mark D as instantiated so that recursive calls to
26848 instantiate_decl do not try to instantiate it again. */
26852 /* Regenerate the declaration in case the template has been modified
26853 by a subsequent redeclaration. */
26856 /* We already set the file and line above. Reset them now in case
26857 they changed as a result of calling regenerate_decl_from_template. */
26861 {
26862 /* Clear out DECL_RTL; whatever was there before may not be right
26863 since we've reset the type of the declaration. */
26867 /* The initializer is placed in DECL_INITIAL by
26868 regenerate_decl_from_template so we don't need to
26869 push/pop_access_scope again here. Pull it out so that
26870 cp_finish_decl can process it. */
26876 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
26877 initializer. That function will defer actual emission until
26878 we have a chance to determine linkage. */
26881 /* Enter the scope of D so that access-checking works correctly. */
26891 }
26895 {
26896 /* Set up the list of local specializations. */
26900 /* Set up context. */
26903 else
26904 {
26908 }
26910 /* Create substitution entries for the parameters. */
26913 /* Substitute into the body of the function. */
26917 else
26918 {
26922 /* Set the current input_location to the end of the function
26923 so that finish_function knows where we are. */
26924 input_location
26927 /* Remember if we saw an infinite loop in the template. */
26928 current_function_infinite_loop
26930 }
26932 /* Finish the function. */
26935 else
26936 {
26939 }
26943 }
26945 /* We're not deferring instantiation any more. */
26953 }
26955 /* Produce the definition of D, a _DECL generated from a template. If
26956 DEFER_OK is true, then we don't have to actually do the
26957 instantiation now; we just have to do it sometime. Normally it is
26958 an error if this is an explicit instantiation but D is undefined.
26959 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
26960 instantiated class template. */
26962 tree
26964 {
26966 tree gen_args;
26967 tree args;
26968 tree td;
26969 tree code_pattern;
26970 tree spec;
26971 tree gen_tmpl;
26979 /* This function should only be used to instantiate templates for
26980 functions and static member variables. */
26983 /* A concept is never instantiated. */
26989 /* We may have a pending instantiation of D itself. */
26992 /* Variables are never deferred; if instantiation is required, they
26993 are instantiated right away. That allows for better code in the
26994 case that an expression refers to the value of the variable --
26995 if the variable has a constant value the referring expression can
26996 take advantage of that fact. */
27000 /* Don't instantiate cloned functions. Instead, instantiate the
27001 functions they cloned. */
27010 /* D has already been instantiated or explicitly specialized, so
27011 there's nothing for us to do here.
27013 It might seem reasonable to check whether or not D is an explicit
27014 instantiation, and, if so, stop here. But when an explicit
27015 instantiation is deferred until the end of the compilation,
27016 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
27017 the instantiation. */
27020 /* Check to see whether we know that this template will be
27021 instantiated in some other file, as with "extern template"
27022 extension. */
27025 /* In general, we do not instantiate such templates. */
27032 /* We should already have the extra args. */
27036 /* And what's in the hash table should match D. */
27038 == d
27041 /* This needs to happen before any tsubsting. */
27047 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
27048 for the instantiation. */
27053 {
27054 /* Look up an explicit specialization, if any. */
27057 {
27060 }
27061 }
27065 /* We should never be trying to instantiate a member of a class
27066 template or partial specialization. */
27071 /* In the case of a friend template whose definition is provided
27072 outside the class, we may have too many arguments. Drop the
27073 ones we don't need. The same is true for specializations. */
27074 args = get_innermost_template_args
27078 {
27084 }
27085 else
27086 {
27090 else
27092 }
27094 /* We may be in the middle of deferred access check. Disable it now. */
27097 /* Unless an explicit instantiation directive has already determined
27098 the linkage of D, remember that a definition is available for
27099 this entity. */
27109 /* If D is a member of an explicitly instantiated class template,
27110 and no definition is available, treat it like an implicit
27111 instantiation. */
27114 {
27115 /* Leave linkage flags alone on instantiations with anonymous
27116 visibility. */
27118 {
27121 }
27123 }
27125 /* Defer all other templates, unless we have been explicitly
27126 forbidden from doing so. */
27128 template. */
27129 ! pattern_defined
27130 /* If it's OK to postpone instantiation, do so. */
27131 || defer_ok
27132 /* If this is a static data member that will be defined
27133 elsewhere, we don't want to instantiate the entire data
27134 member, but we do want to instantiate the initializer so that
27135 we can substitute that elsewhere. */
27137 /* Handle here a deleted function too, avoid generating
27138 its body (c++/61080). */
27140 {
27141 /* The definition of the static data member is now required so
27142 we must substitute the initializer. */
27146 {
27147 tree ns;
27148 tree init;
27157 args,
27159 /* If instantiating the initializer involved instantiating this
27160 again, don't call cp_finish_decl twice. */
27162 {
27163 /* Make sure the initializer is still constant, in case of
27164 circular dependency (template/instantiate6.C). */
27165 const_init
27169 }
27173 }
27175 /* We restore the source position here because it's used by
27176 add_pending_template. */
27182 /* [temp.explicit]
27184 The definition of a non-exported function template, a
27185 non-exported member function template, or a non-exported
27186 member function or static data member of a class template
27187 shall be present in every translation unit in which it is
27188 explicitly instantiated. */
27192 /* If we're in unevaluated context, we just wanted to get the
27193 constant value; this isn't an odr use, so don't queue
27194 a full instantiation. */
27196 /* ??? Historically, we have instantiated inline functions, even
27197 when marked as "extern template". */
27200 }
27201 else
27202 {
27207 }
27216 }
27218 /* Run through the list of templates that we wish we could
27219 instantiate, and instantiate any we can. RETRIES is the
27220 number of times we retry pending template instantiation. */
27222 void
27224 {
27228 /* Instantiating templates may trigger vtable generation. This in turn
27229 may require further template instantiations. We place a limit here
27230 to avoid infinite loop. */
27232 {
27236 "template instantiation depth exceeds maximum of %d"
27237 " instantiating %q+D, possibly from virtual table generation"
27241 /* Pretend that we defined it. */
27244 }
27246 do
27247 {
27252 {
27257 {
27259 {
27274 }
27277 }
27278 else
27279 {
27282 {
27283 instantiation
27289 }
27293 }
27296 {
27297 /* If INSTANTIATION has been instantiated, then we don't
27298 need to consider it again in the future. */
27303 }
27304 else
27305 {
27308 }
27311 }
27313 }
27317 }
27319 /* Substitute ARGVEC into T, which is a list of initializers for
27320 either base class or a non-static data member. The TREE_PURPOSEs
27321 are DECLs, and the TREE_VALUEs are the initializer values. Used by
27322 instantiate_decl. */
27324 static tree
27326 {
27331 {
27332 tree decl;
27333 tree init;
27339 {
27340 tree expr;
27341 tree arg;
27343 /* Expand the base class expansion type into separate base
27344 classes. */
27346 tf_warning_or_error,
27347 NULL_TREE);
27351 /* We'll be building separate TREE_LISTs of arguments for
27352 each base. */
27358 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
27359 expand each argument in the TREE_VALUE of t. */
27366 /* VOID_TYPE_NODE is used to indicate
27367 value-initialization. */
27368 {
27371 }
27372 else
27373 {
27374 /* Substitute parameter packs into each argument in the
27375 TREE_LIST. */
27378 {
27379 tree expanded_exprs;
27381 /* Expand the argument. */
27382 tree value;
27385 else
27386 {
27389 }
27390 expanded_exprs
27392 tf_warning_or_error,
27393 NULL_TREE);
27397 /* Prepend each of the expanded expressions to the
27398 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
27406 else
27411 }
27414 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
27415 since we built them backwards. */
27417 {
27420 }
27421 }
27422 }
27425 {
27427 {
27431 }
27432 else
27433 {
27434 tree tmp;
27448 /* If we had an initializer but it instantiated to nothing,
27449 value-initialize the object. This will only occur when
27450 the initializer was a pack expansion where the parameter
27451 packs used in that expansion were of length zero. */
27454 }
27458 {
27460 decl);
27462 }
27463 /* Look for a target constructor. */
27467 {
27470 {
27474 }
27476 }
27479 {
27481 /* Carry over the dummy TREE_TYPE node containing the source
27482 location. */
27486 }
27487 }
27488 }
27490 }
27492 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
27493 is the instantiation (which should have been created with
27494 start_enum) and ARGS are the template arguments to use. */
27496 static void
27498 {
27499 tree e;
27505 {
27506 tree value;
27509 /* Note that in a template enum, the TREE_VALUE is the
27510 CONST_DECL, not the corresponding INTEGER_CST. */
27514 /* Give this enumeration constant the correct access. */
27517 /* Actually build the enumerator itself. Here we're assuming that
27518 enumerators can't have dependent attributes. */
27522 /* Attribute deprecated without an argument isn't sticky: it'll
27523 melt into a tree flag, so we need to propagate the flag here,
27524 since we just created a new enumerator. */
27527 }
27539 }
27541 /* DECL is a FUNCTION_DECL that is a template specialization. Return
27542 its type -- but without substituting the innermost set of template
27543 arguments. So, innermost set of template parameters will appear in
27544 the type. */
27546 tree
27548 {
27549 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
27551 }
27553 /* Return truthvalue if we're processing a template different from
27554 the last one involved in diagnostics. */
27555 bool
27557 {
27559 }
27561 /* Remember current template involved in diagnostics. */
27562 void
27564 {
27566 }
27570 {
27572 }
27574 /* Return TRUE if current_function_decl is being instantiated, false
27575 otherwise. */
27577 bool
27579 {
27583 }
27585 /* [temp.param] Check that template non-type parm TYPE is of an allowable
27586 type. Return false for ok, true for disallowed. Issue error and
27587 inform messages under control of COMPLAIN. */
27589 static bool
27591 {
27602 {
27604 {
27609 }
27611 }
27616 /* Fall through; before C++11 alias templates, a bound ttp
27619 /* Any other wildcard type not already handled above is allowed. */
27626 {
27634 {
27635 auto_diagnostic_group d;
27639 }
27641 }
27643 {
27648 }
27651 {
27654 else
27656 type);
27657 }
27659 }
27661 /* Returns true iff the noexcept-specifier for TYPE is value-dependent. */
27663 static bool
27665 {
27668 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
27669 affect overload resolution and treating it as dependent breaks
27670 things. Same for an unparsed noexcept expression. */
27677 }
27679 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
27680 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
27682 static bool
27684 {
27685 tree scope;
27687 /* [temp.dep.type]
27689 A type is dependent if it is:
27691 -- a template parameter. Template template parameters are types
27692 for us (since TYPE_P holds true for them) so we handle
27693 them here. */
27697 /* -- a qualified-id with a nested-name-specifier which contains a
27698 class-name that names a dependent type or whose unqualified-id
27699 names a dependent type. */
27703 /* An alias template specialization can be dependent even if the
27704 resulting type is not. */
27708 /* -- a cv-qualified type where the cv-unqualified type is
27709 dependent.
27710 No code is necessary for this bullet; the code below handles
27711 cv-qualified types, and we don't want to strip aliases with
27712 TYPE_MAIN_VARIANT because of DR 1558. */
27713 /* -- a compound type constructed from any dependent type. */
27721 {
27722 tree arg_type;
27727 arg_type;
27733 /* A value-dependent noexcept-specifier makes the type dependent. */
27736 }
27737 /* -- an array type constructed from any dependent type or whose
27738 size is specified by a constant expression that is
27739 value-dependent.
27741 We checked for type- and value-dependence of the bounds in
27742 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
27744 {
27749 }
27751 /* -- a template-id in which either the template name is a template
27752 parameter ... */
27755 /* ... or any of the template arguments is a dependent type or
27756 an expression that is type-dependent or value-dependent. */
27758 && (any_dependent_template_arguments_p
27762 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and TRAIT_TYPEs are
27763 dependent; if the argument of the `typeof' expression is not
27764 type-dependent, then it should already been have resolved. */
27770 /* A template argument pack is dependent if any of its packed
27771 arguments are. */
27773 {
27778 }
27780 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
27781 be template parameters. */
27791 /* The standard does not specifically mention types that are local
27792 to template functions or local classes, but they should be
27793 considered dependent too. For example:
27795 template <int I> void f() {
27796 enum E { a = I };
27797 S<sizeof (E)> s;
27798 }
27800 The size of `E' cannot be known until the value of `I' has been
27801 determined. Therefore, `E' must be considered dependent. */
27805 /* Don't use type_dependent_expression_p here, as it can lead
27806 to infinite recursion trying to determine whether a lambda
27807 nested in a lambda is dependent (c++/47687). */
27811 && (any_dependent_template_arguments_p
27815 /* Other types are non-dependent. */
27817 }
27819 /* Returns TRUE if TYPE is dependent, in the sense of
27820 [temp.dep.type]. Note that a NULL type is considered dependent. */
27822 bool
27824 {
27825 /* If there are no template parameters in scope, then there can't be
27826 any dependent types. */
27828 {
27829 /* If we are not processing a template, then nobody should be
27830 providing us with a dependent type. */
27834 }
27836 /* If the type is NULL, we have not computed a type for the entity
27837 in question; in that case, the type is dependent. */
27841 /* Erroneous types can be considered non-dependent. */
27845 /* If we have not already computed the appropriate value for TYPE,
27846 do so now. */
27848 {
27851 }
27854 }
27856 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
27857 lookup. In other words, a dependent type that is not the current
27858 instantiation. */
27860 bool
27862 {
27865 }
27867 /* True if we might find more declarations in SCOPE during instantiation than
27868 we can when parsing the template. */
27870 bool
27872 {
27874 }
27876 /* T is a SCOPE_REF. Return whether it represents a non-static member of
27877 an unknown base of 'this' (and is therefore instantiation-dependent). */
27879 static bool
27881 {
27898 }
27900 /* T is a SCOPE_REF; return whether we need to consider it
27901 instantiation-dependent so that we can check access at instantiation
27902 time even though we know which member it resolves to. */
27904 static bool
27906 {
27914 else
27916 }
27918 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
27919 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
27920 expression. */
27922 /* Note that this predicate is not appropriate for general expressions;
27923 only constant expressions (that satisfy potential_constant_expression)
27924 can be tested for value dependence. */
27926 bool
27928 {
27932 /* A type-dependent expression is also value-dependent. */
27937 {
27939 /* A dependent member function of the current instantiation. */
27943 /* A dependent member function of the current instantiation. */
27950 /* A name that has not been looked up -- must be dependent. */
27954 /* A non-type template parm. */
27958 /* A non-type template parm. */
27964 /* A constant with literal type and is initialized
27965 with an expression that is value-dependent. */
27969 {
27972 /* __PRETTY_FUNCTION__ inside a template function is dependent
27973 on the name of the function. */
27975 /* It might be used in a template, but not a template
27976 function, in which case its DECL_VALUE_EXPR will be
27977 "top level". */
27980 }
27982 /* FIXME cp_finish_decl doesn't fold reference initializers. */
27992 /* These expressions are value-dependent if the type to which
27993 the cast occurs is dependent or the expression being casted
27994 is value-dependent. */
27995 {
28001 /* A functional cast has a list of operands. */
28004 {
28005 /* If there are no operands, it must be an expression such
28006 as "int()". This should not happen for aggregate types
28007 because it would form non-constant expressions. */
28012 }
28022 }
28027 /* FALLTHRU */
28030 /* A `sizeof' expression is value-dependent if the operand is
28031 type-dependent or is a pack expansion. */
28040 /* An 'encode' expression is value-dependent if the operand is
28041 type-dependent. */
28050 /* All instantiation-dependent expressions should also be considered
28051 value-dependent. */
28059 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
28060 is value-dependent. */
28067 {
28083 }
28094 {
28098 }
28101 /* Treat all requires-expressions as value-dependent so
28102 we don't try to fold them. */
28109 {
28116 {
28118 /* In a call to a constexpr member function, look through the
28119 implicit ADDR_EXPR on the object argument so that it doesn't
28120 cause the call to be considered value-dependent. We also
28121 look through it in potential_constant_expression. */
28128 }
28130 }
28137 {
28139 tree val;
28146 }
28149 /* Treat a GNU statement expression as dependent to avoid crashing
28150 under instantiate_non_dependent_expr; it can't be constant. */
28155 /* The second operand is a type, which type_dependent_expression_p
28156 (and therefore value_dependent_expression_p) doesn't want to see. */
28162 /* A constant expression is value-dependent if any subexpression is
28163 value-dependent. */
28165 {
28172 {
28176 {
28179 /* In some cases, some of the operands may be missing.
28180 (For example, in the case of PREDECREMENT_EXPR, the
28181 amount to increment by may be missing.) That doesn't
28182 make the expression dependent. */
28185 }
28186 }
28190 }
28192 }
28194 /* The expression is not value-dependent. */
28196 }
28198 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
28199 [temp.dep.expr]. Note that an expression with no type is
28200 considered dependent. Other parts of the compiler arrange for an
28201 expression with type-dependent subexpressions to have no type, so
28202 this function doesn't have to be fully recursive. */
28204 bool
28206 {
28217 /* An unresolved name is always dependent. */
28223 /* A lambda-expression in template context is dependent. dependent_type_p is
28224 true for a lambda in the scope of a class or function template, but that
28225 doesn't cover all template contexts, like a default template argument. */
28229 /* A fold expression is type-dependent. */
28236 /* Some expression forms are never type-dependent. */
28249 /* The types of these expressions depends only on the type to which
28250 the cast occurs. */
28259 /* The types of these expressions depends only on the type created
28260 by the expression. */
28263 {
28264 /* For NEW_EXPR tree nodes created inside a template, either
28265 the object type itself or a TREE_LIST may appear as the
28266 operand 1. */
28269 /* This is an array type. We need to check array dimensions
28270 as well. */
28272 || value_dependent_expression_p
28274 /* Array type whose dimension has to be deduced. */
28278 else
28280 }
28283 {
28287 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
28288 contains an identifier associated by name lookup with one or more
28289 declarations declared with a dependent type, or...a
28290 nested-name-specifier or qualified-id that names a member of an
28291 unknown specialization. */
28294 }
28304 {
28309 }
28311 /* A static data member of the current instantiation with incomplete
28312 array type is type-dependent, as the definition and specializations
28313 can have different bounds. */
28320 /* An array of unknown bound depending on a variadic parameter, eg:
28322 template<typename... Args>
28323 void foo (Args... args)
28324 {
28325 int arr[] = { args... };
28326 }
28328 template<int... vals>
28329 void bar ()
28330 {
28331 int arr[] = { vals... };
28332 }
28334 If the array has no length and has an initializer, it must be that
28335 we couldn't determine its length in cp_complete_array_type because
28336 it is dependent. */
28344 /* Pull a FUNCTION_DECL out of a BASELINK if we can. */
28346 {
28351 }
28353 /* A function or variable template-id is type-dependent if it has any
28354 dependent template arguments. */
28358 {
28359 /* Consider the innermost template arguments, since those are the ones
28360 that come from the template-id; the template arguments for the
28361 enclosing class do not make it type-dependent unless they are used in
28362 the type of the decl. */
28364 && (any_dependent_template_arguments_p
28367 }
28369 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
28370 type-dependent. Checking this is important for functions with auto return
28371 type, which looks like a dependent type. */
28380 {
28384 }
28386 /* Otherwise, its constraints could still depend on outer template parameters
28387 from its (dependent) scope. */
28389 /* As an optimization, check this cheaper sufficient condition first.
28390 (At this point we've established that we're looking at a member of
28391 a dependent class, so it makes sense to start treating say undeduced
28392 auto as dependent.) */
28397 /* Always dependent, on the number of arguments if nothing else. */
28402 {
28407 {
28413 }
28414 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
28418 /* CO_AWAIT/YIELD_EXPR with unknown type is always dependent. */
28424 {
28429 }
28432 {
28439 }
28448 }
28450 /* The type of a non-type template parm declared with a placeholder type
28451 depends on the corresponding template argument, even though
28452 placeholders are not normally considered dependent. */
28459 /* Dependent type attributes might not have made it from the decl to
28460 the type yet. */
28466 }
28468 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
28469 type-dependent if the expression refers to a member of the current
28470 instantiation and the type of the referenced member is dependent, or the
28471 class member access expression refers to a member of an unknown
28472 specialization.
28474 This function returns true if the OBJECT in such a class member access
28475 expression is of an unknown specialization. */
28477 bool
28479 {
28480 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
28481 dependent. */
28486 }
28488 /* walk_tree callback function for instantiation_dependent_expression_p,
28489 below. Returns non-zero if a dependent subexpression is found. */
28491 static tree
28494 {
28496 {
28497 /* We don't have to worry about decltype currently because decltype
28498 of an instantiation-dependent expr is a dependent type. This
28499 might change depending on the resolution of DR 1172. */
28502 }
28505 {
28506 /* Don't treat an argument list as dependent just because it has no
28507 TREE_TYPE. */
28518 /* We'll check value-dependence separately. */
28521 /* Handle expressions with type operands. */
28526 {
28531 {
28534 else
28535 {
28538 }
28539 }
28541 }
28545 /* In a template, finish_class_member_access_expr creates a
28546 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
28547 type-dependent, so that we can check access control at
28548 instantiation time (PR 42277). See also Core issue 1273. */
28555 else
28558 /* Treat statement-expressions as dependent. */
28562 /* Treat requires-expressions as dependent. */
28573 /* Before C++17, a noexcept-specifier isn't part of the function type
28574 so it doesn't affect type dependence, but we still want to consider it
28575 for instantiation dependence. */
28584 }
28588 else
28590 }
28592 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
28593 sense defined by the ABI:
28595 "An expression is instantiation-dependent if it is type-dependent
28596 or value-dependent, or it has a subexpression that is type-dependent
28597 or value-dependent."
28599 Except don't actually check value-dependence for unevaluated expressions,
28600 because in sizeof(i) we don't care about the value of i. Checking
28601 type-dependence will in turn check value-dependence of array bounds/template
28602 arguments as needed. */
28604 bool
28606 {
28607 tree result;
28618 }
28620 /* As above, but also check value-dependence of the expression as a whole. */
28622 bool
28624 {
28626 || (processing_template_decl
28629 }
28631 /* Like type_dependent_expression_p, but it also works while not processing
28632 a template definition, i.e. during substitution or mangling. */
28634 bool
28636 {
28642 }
28644 /* Returns TRUE if ARGS contains a type-dependent expression. */
28646 bool
28648 {
28657 }
28659 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
28660 expressions) contains any type-dependent expressions. */
28662 bool
28664 {
28670 }
28672 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
28673 expressions) contains any value-dependent expressions. */
28675 bool
28677 {
28683 }
28685 /* Returns TRUE if the ARG (a template argument) is dependent. */
28687 bool
28689 {
28693 /* Assume a template argument that was wrongly written by the user
28694 is dependent. This is consistent with what
28695 any_dependent_template_arguments_p [that calls this function]
28696 does. */
28706 {
28709 /* A member template of a dependent class is not necessarily
28710 type-dependent, but it is a dependent template argument because it
28711 will be a member of an unknown specialization to that template. */
28714 }
28716 {
28722 }
28725 else
28727 }
28729 /* Identify any expressions that use function parms. */
28731 static tree
28733 {
28736 {
28739 }
28741 }
28743 /* Returns true if a type specialization formed using the template
28744 arguments ARGS needs to use structural equality. */
28746 bool
28748 {
28758 {
28761 {
28767 {
28768 /* Look inside the argument pack. */
28771 }
28774 {
28783 /* An any_targ_node argument (added by add_defaults_to_ttp)
28784 makes the corresponding specialization not canonicalizable,
28785 since template_args_equal always return true for it. We
28786 may see this when called from bind_template_template_parm. */
28788 /* Checking current_function_decl because this structural
28789 comparison is only necessary for redeclaration. */
28792 && (cp_walk_tree_without_duplicates
28794 /* The identity of a class template specialization that uses
28795 a function parameter depends on the identity of the function.
28796 And if this specialization appeared in the trailing return
28797 type thereof, we don't know the identity of the function
28798 (e.g. if it's a redeclaration or a new function) until we
28799 form its signature and go through duplicate_decls. Thus
28800 it's unsafe to decide on a canonical type now (which depends
28801 on the DECL_CONTEXT of the function parameter, which can get
28802 mutated after the fact by duplicate_decls), so just require
28803 structural equality in this case (PR52830). */
28805 }
28806 }
28807 }
28810 }
28812 /* Returns true if ARGS (a collection of template arguments) contains
28813 any dependent arguments. */
28815 bool
28817 {
28824 {
28829 }
28832 }
28834 /* Returns true if ARGS contains any errors. */
28836 bool
28838 {
28846 {
28849 else
28851 }
28857 {
28862 }
28865 }
28867 /* Returns TRUE if the template TMPL is type-dependent. */
28869 bool
28871 {
28873 {
28878 }
28880 /* Template template parameters are dependent. */
28884 /* So are names that have not been looked up. */
28888 }
28890 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
28892 bool
28894 {
28897 }
28899 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
28900 are dependent. */
28902 bool
28904 {
28911 {
28936 {
28940 }
28944 {
28948 {
28954 /* If this loop has a class iterator with != comparison
28955 with increment other than i++/++i/i--/--i, make sure the
28956 increment is constant. */
28959 {
28962 else
28966 }
28967 }
28968 }
28969 }
28972 }
28974 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
28975 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
28976 no such TYPE can be found. Note that this function peers inside
28977 uninstantiated templates and therefore should be used only in
28978 extremely limited situations. ONLY_CURRENT_P restricts this
28979 peering to the currently open classes hierarchy (which is required
28980 when comparing types). */
28982 tree
28984 {
28985 tree scope;
28986 tree name;
28987 tree decl;
28989 tree pushed_scope;
28990 tree result;
28995 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
28998 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
28999 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of a
29000 TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL
29001 representing the typedef. In that case TYPE_IDENTIFIER (type) is
29002 not the non-qualified identifier of the TYPENAME_TYPE anymore.
29003 So by getting the TYPE_IDENTIFIER of the _main declaration_ of
29004 the TYPENAME_TYPE instead, we avoid messing up with a possible
29005 typedef variant case. */
29008 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
29009 it first before we can figure out what NAME refers to. */
29011 {
29013 /* Given a class template A with a dependent base with nested type C,
29014 typedef typename A::C::C C will land us here, as trying to resolve
29015 the initial A::C leads to the local C typedef, which leads back to
29016 A::C::C. So we break the recursion now. */
29018 else
29020 }
29021 /* If we don't know what SCOPE refers to, then we cannot resolve the
29022 TYPENAME_TYPE. */
29025 /* If this is a typedef, we don't want to look inside (c++/11987). */
29028 /* If SCOPE isn't the template itself, it will not have a valid
29029 TYPE_FIELDS list. */
29031 /* scope is either the template itself or a compatible instantiation
29032 like X<T>, so look up the name in the original template. */
29034 /* If scope has no fields, it can't be a current instantiation. Check this
29035 before currently_open_class to avoid infinite recursion (71515). */
29038 /* If the SCOPE is not the current instantiation, there's no reason
29039 to look inside it. */
29042 /* Enter the SCOPE so that name lookup will be resolved as if we
29043 were in the class definition. In particular, SCOPE will no
29044 longer be considered a dependent type. */
29046 /* Look up the declaration. */
29048 tf_warning_or_error);
29052 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
29053 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
29059 {
29063 }
29066 {
29067 /* Obtain the template and the arguments. */
29070 {
29071 /* We get here with a plain identifier because a previous tentative
29072 parse of the nested-name-specifier as part of a ptr-operator saw
29073 ::template X<A>. The use of ::template is necessary in a
29074 ptr-operator, but wrong in a declarator-id.
29076 [temp.names]: In a qualified-id of a declarator-id, the keyword
29077 template shall not appear at the top level. */
29081 }
29083 /* Instantiate the template. */
29089 }
29091 /* Leave the SCOPE. */
29095 /* If we failed to resolve it, return the original typename. */
29099 /* If lookup found a typename type, resolve that too. */
29101 {
29102 /* Ill-formed programs can cause infinite recursion here, so we
29103 must catch that. */
29107 }
29109 /* Qualify the resulting type. */
29115 }
29117 /* EXPR is an expression which is not type-dependent. Return a proxy
29118 for EXPR that can be used to compute the types of larger
29119 expressions containing EXPR. */
29121 tree
29123 {
29125 tree inner_expr;
29127 /* When checking, try to get a constant value for all non-dependent
29128 expressions in order to expose bugs in *_dependent_expression_p
29129 and constexpr. This can affect code generation, see PR70704, so
29130 only do this for -fchecking=2. */
29133 /* Don't do this during nsdmi parsing as it can lead to
29134 unexpected recursive instantiations. */
29136 /* Don't do this during concept processing either and for
29137 the same reason. */
29143 /* Preserve OVERLOADs; the functions must be available to resolve
29144 types. */
29155 /* There is no need to return a proxy for a variable, parameter
29156 or enumerator. */
29160 /* Preserve string constants; conversions from string constants to
29161 "char *" are allowed, even though normally a "const char *"
29162 cannot be used to initialize a "char *". */
29165 /* Preserve void and arithmetic constants, as an optimization -- there is no
29166 reason to create a new node. */
29171 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
29172 There is at least one place where we want to know that a
29173 particular expression is a throw-expression: when checking a ?:
29174 expression, there are special rules if the second or third
29175 argument is a throw-expression. */
29179 /* Don't wrap an initializer list, we need to be able to look inside. */
29183 /* Don't wrap a dummy object, we need to be able to test for it. */
29201 /* If the type is unknown, it can't really be non-dependent */
29204 /* Otherwise, build a NON_DEPENDENT_EXPR. */
29207 }
29209 /* ARGS is a vector of expressions as arguments to a function call.
29210 Replace the arguments with equivalent non-dependent expressions.
29211 This modifies ARGS in place. */
29213 void
29215 {
29217 tree arg;
29220 {
29224 }
29225 }
29227 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
29228 TEMPLATE_TYPE_PARM with a level one deeper than the actual template parms,
29229 by default. If set_canonical is true, we set TYPE_CANONICAL on it. */
29231 static tree
29233 {
29249 }
29251 tree
29253 {
29255 }
29257 tree
29259 {
29261 }
29263 /* Return a C++17 deduction placeholder for class template TMPL.
29264 There are represented as an 'auto' with the special level 0 and
29265 CLASS_PLACEHOLDER_TEMPLATE set. */
29267 tree
29269 {
29272 /* Our canonical type depends on the placeholder. */
29275 }
29277 /* True iff T is a C++17 class template deduction placeholder. */
29279 bool
29281 {
29283 }
29285 /* Make a "constrained auto" type-specifier. This is an auto or
29286 decltype(auto) type with constraints that must be associated after
29287 deduction. The constraint is formed from the given concept CON
29288 and its optional sequence of template arguments ARGS.
29290 TYPE must be the result of make_auto_type or make_decltype_auto_type. */
29292 static tree
29294 {
29295 /* Build the constraint. */
29307 /* Our canonical type depends on the constraint. */
29310 /* Attach the constraint to the type declaration. */
29312 }
29314 /* Make a "constrained auto" type-specifier. */
29316 tree
29318 {
29321 }
29323 /* Make a "constrained decltype(auto)" type-specifier. */
29325 tree
29327 {
29330 }
29332 /* Returns true if the placeholder type constraint T has any dependent
29333 (explicit) template arguments. */
29335 static bool
29337 {
29342 {
29345 }
29352 }
29354 /* Build and return a concept definition. Like other templates, the
29355 CONCEPT_DECL node is wrapped by a TEMPLATE_DECL. This returns the
29356 the TEMPLATE_DECL. */
29358 tree
29360 {
29366 /* A concept-definition shall not have associated constraints. */
29368 {
29371 }
29373 /* A concept-definition shall appear in namespace scope. Templates
29374 aren't allowed in block scope, so we only need to check for class
29375 scope. */
29377 {
29380 }
29383 {
29386 }
29388 /* Initially build the concept declaration; its type is bool. */
29398 /* Push the enclosing template. */
29400 }
29402 /* Given type ARG, return std::initializer_list<ARG>. */
29404 static tree
29406 {
29411 {
29415 "deducing from brace-enclosed initializer list"
29419 }
29425 }
29427 /* Replace auto in TYPE with std::initializer_list<auto>. */
29429 static tree
29431 {
29438 }
29440 /* Hash traits for hashing possibly constrained 'auto'
29441 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
29444 {
29447 };
29449 /* Hash the 'auto' T. */
29451 inline hashval_t
29453 {
29455 /* Matching constrained-type-specifiers denote the same template
29456 parameter, so hash the constraint. */
29458 else
29459 /* But unconstrained autos are all separate, so just hash the pointer. */
29461 }
29463 /* Compare two 'auto's. */
29467 {
29474 /* Two unconstrained autos are distinct. */
29479 }
29481 /* for_each_template_parm callback for extract_autos: if t is a (possibly
29482 constrained) auto, add it to the vector. */
29484 static int
29486 {
29489 {
29490 /* All the autos were built with index 0; fix that up now. */
29494 /* If this is a repeated constrained-type-specifier, use the index we
29495 chose before. */
29497 else
29498 {
29499 /* Otherwise this is new, so use the current count. */
29502 }
29504 {
29509 }
29510 }
29512 /* Always keep walking. */
29514 }
29516 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
29517 says they can appear anywhere in the type. */
29519 static tree
29521 {
29529 {
29533 }
29536 }
29538 /* The stem for deduction guide names. */
29541 /* Return the name for a deduction guide for class template TMPL. */
29543 tree
29545 {
29556 }
29558 /* True if NAME is the name of a deduction guide. */
29560 bool
29562 {
29566 }
29568 /* True if FN is a deduction guide. */
29570 bool
29572 {
29577 }
29579 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
29581 bool
29583 {
29590 }
29592 /* True if FN is a guide generated from a constructor template. */
29594 bool
29596 {
29604 }
29606 /* True if FN is an aggregate initialization guide or the copy deduction
29607 guide. */
29609 bool
29611 {
29615 /* Explicitly declared. */
29618 /* Derived from a constructor. */
29621 }
29623 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
29624 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
29625 template parameter types. Note that the handling of template template
29626 parameters relies on current_template_parms being set appropriately for the
29627 new template. */
29629 static tree
29632 {
29638 tree newtype;
29641 {
29645 }
29646 else
29647 {
29650 {
29651 // Substitute once to fix references to other template parameters.
29654 // Now substitute again to reduce the level of the auto.
29657 }
29658 else
29661 }
29663 tree newdecl
29668 tree newidx;
29671 {
29680 {
29685 // First create a copy (ttargs) of tsubst_args with an
29686 // additional level for the template template parameter's own
29687 // template parameters (ttparms).
29688 tree ttparms = (INNERMOST_TEMPLATE_PARMS
29696 // Substitute ttargs into ttparms to fix references to
29697 // other template parameters.
29700 // Now substitute again with args based on tparms, to reduce
29701 // the level of the ttparms.
29704 complain);
29705 // Finally, tack the adjusted parms onto tparms.
29708 // As with all template template parms, the parameter list captured
29709 // by this template template parm that corresponds to its own level
29710 // should be empty. This avoids infinite recursion when structurally
29711 // comparing two such rewritten template template parms (PR102479).
29716 // All done.
29718 }
29722 else
29724 }
29725 else
29726 {
29728 tree newconst
29740 }
29743 }
29745 /* As rewrite_template_parm, but for the whole TREE_LIST representing a
29746 template parameter. */
29748 static tree
29751 {
29766 }
29768 /* Returns a C++17 class deduction guide template based on the constructor
29769 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
29770 guide, REFERENCE_TYPE for an implicit copy/move guide, or TREE_LIST for an
29771 aggregate initialization guide. OUTER_ARGS are the template arguments
29772 for the enclosing scope of the class. */
29774 static tree
29776 {
29780 location_t loc;
29784 {
29788 }
29791 {
29793 {
29797 else
29799 }
29802 else
29812 }
29813 else
29814 {
29820 fn_tmpl
29828 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
29829 fully specialized args for the enclosing class. Strip those off, as
29830 the deduction guide won't have those template parameters. */
29833 /* Discard the 'this' parameter. */
29841 {
29844 /* For a member template constructor, we need to flatten the two
29845 template parameter lists into one, and then adjust the function
29846 signature accordingly. This gets...complicated. */
29849 /* For a member template we should have two levels of parms/args, one
29850 for the class and one for the constructor. We stripped
29851 specialized args for further enclosing classes above. */
29855 /* Template args for translating references to the two-level template
29856 parameters into references to the one-level template parameters we
29857 are creating. */
29862 /* Template parms for the constructor template. */
29865 /* Template parms for the class template. */
29869 /* Template parms for the deduction guide start as a copy of the
29870 template parms for the class. We set current_template_parms for
29871 lookup_template_class_1. */
29877 /* Now we need to rewrite the constructor parms to append them to the
29878 class parms. */
29880 {
29884 tree newelt
29890 }
29892 /* Now we have a final set of template parms to substitute into the
29893 function signature. */
29900 {
29902 /* FIXME: We'd like to avoid substituting outer template
29903 arguments into the constraint ahead of time, but the
29904 construction of tsubst_args assumes that outer arguments
29905 are already substituted in. */
29908 }
29910 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped if
29911 cp_unevaluated_operand. */
29912 cp_evaluated ev;
29915 }
29916 else
29917 {
29918 /* Substitute in the same arguments to rewrite class members into
29919 references to members of an unknown specialization. */
29920 cp_evaluated ev;
29924 {
29926 /* FIXME: As above. */
29929 }
29930 }
29935 }
29938 {
29939 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
29943 }
29947 FUNCTION_DECL,
29962 }
29964 /* Add to LIST the member types for the reshaped initializer CTOR. */
29966 static tree
29968 {
29972 {
29976 {
29982 }
29986 /* Give the trailing pack expansion parameter a default argument to
29987 match aggregate initialization behavior, even if we deduce the
29988 length of the pack separately to more than we have initializers. */
29990 /* if ei is of array type and xi is a braced-init-list or string literal,
29991 Ti is an rvalue reference to the declared type of ei */
29996 {
29998 ftype = cp_build_qualified_type
30000 ftype = (cp_build_reference_type
30002 }
30004 }
30007 }
30009 /* Return whether ETYPE is, or is derived from, a specialization of TMPL. */
30011 static bool
30013 {
30019 tree tparms = (INNERMOST_TEMPLATE_PARMS
30026 }
30030 /* Return a C++20 aggregate deduction candidate for TYPE initialized from
30031 INIT. */
30033 static tree
30035 {
30043 {
30049 }
30051 /* We might be creating a guide for a class member template, e.g.,
30053 template<typename U> struct A {
30054 template<typename T> struct B { T t; };
30055 };
30057 At this point, A will have been instantiated. Below, we need to
30058 use both A<U>::B<T> (TEMPLATE_TYPE) and A<int>::B<T> (TYPE) types. */
30059 const bool member_template_p
30063 tree template_type = (member_template_p
30069 /* No aggregate candidate for copy-initialization. */
30071 {
30075 }
30077 /* If we encounter a problem, we just won't add the candidate. */
30082 {
30087 /* If we're creating a deduction guide for a member class template,
30088 we've used the original template pattern type for the reshape_init
30089 above; this is done because we want PARMS to be a template parameter
30090 type, something that can be deduced when used as a function template
30091 parameter. At this point the outer class template has already been
30092 partially instantiated (we deferred the deduction until the enclosing
30093 scope is non-dependent). Therefore we have to partially instantiate
30094 PARMS, so that its template level is properly reduced and we don't get
30095 mismatches when deducing types using the guide with PARMS. */
30097 {
30101 }
30102 }
30104 {
30107 len;
30109 {
30115 }
30116 }
30117 else
30118 /* Aggregate initialization doesn't apply to an initializer expression. */
30122 {
30128 }
30131 }
30133 /* UGUIDES are the deduction guides for the underlying template of alias
30134 template TMPL; adjust them to be deduction guides for TMPL. */
30136 static tree
30138 {
30139 /* [over.match.class.deduct]: When resolving a placeholder for a deduced
30140 class type (9.2.8.2) where the template-name names an alias template A,
30141 the defining-type-id of A must be of the form
30143 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
30145 as specified in 9.2.8.2. The guides of A are the set of functions or
30146 function templates formed as follows. For each function or function
30147 template f in the guides of the template named by the simple-template-id
30148 of the defining-type-id, the template arguments of the return type of f
30149 are deduced from the defining-type-id of A according to the process in
30150 13.10.2.5 with the exception that deduction does not fail if not all
30151 template arguments are deduced. Let g denote the result of substituting
30152 these deductions into f. If substitution succeeds, form a function or
30153 function template f' with the following properties and add it to the set
30154 of guides of A:
30156 * The function type of f' is the function type of g.
30158 * If f is a function template, f' is a function template whose template
30159 parameter list consists of all the template parameters of A (including
30160 their default template arguments) that appear in the above deductions or
30161 (recursively) in their default template arguments, followed by the
30162 template parameters of f that were not deduced (including their default
30163 template arguments), otherwise f' is not a function template.
30165 * The associated constraints (13.5.2) are the conjunction of the
30166 associated constraints of g and a constraint that is satisfied if and only
30167 if the arguments of A are deducible (see below) from the return type.
30169 * If f is a copy deduction candidate (12.4.1.8), then f' is considered to
30170 be so as well.
30172 * If f was generated from a deduction-guide (12.4.1.8), then f' is
30173 considered to be so as well.
30175 * The explicit-specifier of f' is the explicit-specifier of g (if
30176 any). */
30186 {
30193 {
30197 /* Deduce template arguments for f from the type-id of A. */
30203 /* CWG2664: Discard any deductions, still build the guide. */
30207 /* The number of parms for f' is the number of parms of A used in
30208 the deduced arguments plus non-deduced parms of f. */
30220 /* Set current_template_parms as in build_deduction_guide. */
30228 /* First copy over the used parms of A. */
30231 {
30234 {
30239 }
30240 }
30243 /* Adjust the deduced template args for f to refer to the A parms
30244 with their new indexes. */
30248 /* Now rewrite the non-deduced parms of f. */
30251 {
30258 }
30261 /* Substitute the deduced arguments plus the rewritten template
30262 parameters into f to get g. This covers the type, copyness,
30263 guideness, and explicit-specifier. */
30264 tree g;
30265 {
30266 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped
30267 if cp_unevaluated_operand. */
30268 cp_evaluated ev;
30270 }
30274 {
30275 /* The targs are all non-dependent, so g isn't a template. */
30279 }
30288 /* Substitute the associated constraints. */
30295 /* Add a constraint that the return type matches the instantiation of
30296 A with the same template arguments. */
30299 /* FIXME this should mean they don't compare as equivalent. */
30301 {
30304 }
30307 {
30310 }
30311 }
30312 else
30313 {
30314 /* For a non-template deduction guide, if the arguments of A aren't
30315 deducible from the return type, don't add the candidate. */
30316 non_template:
30319 }
30322 }
30325 }
30327 /* True iff template arguments for TMPL can be deduced from TYPE.
30328 Used to implement CPTK_IS_DEDUCIBLE for alias CTAD according to
30329 [over.match.class.deduct].
30331 This check is specified in terms of partial specialization, so the behavior
30332 should be parallel to that of get_partial_spec_bindings. */
30334 bool
30336 {
30342 /* If tmpl is a class template, this is trivial: it's deducible if TYPE is a
30343 specialization of TMPL. */
30349 /* Otherwise it's an alias template. */
30350 again:
30355 /* We don't fail on an undeduced targ the second time through (like
30356 get_partial_spec_bindings) because we're going to try defaults. */
30359 {
30365 {
30370 }
30371 /* If the type parameter is a parameter pack, then it will be deduced
30372 to an empty parameter pack. This is another case that doesn't model
30373 well as partial specialization. */
30375 {
30376 tree arg;
30378 {
30381 }
30382 else
30386 }
30387 }
30389 /* Maybe add in default template args. This seems like a flaw in the
30390 specification in terms of partial specialization, since it says the
30391 partial specialization has the the template parameter list of A, but a
30392 partial specialization can't have default targs. */
30397 /* I believe we don't need the template_template_parm_bindings_ok_p call
30398 because coerce_template_parms did coerce_template_template_parms. */
30401 }
30403 /* Return artificial deduction guides built from the constructors of class
30404 template TMPL. */
30406 static tree
30408 {
30415 {
30416 /* Skip inherited constructors. */
30422 }
30424 /* Add implicit default constructor deduction guide. */
30426 {
30428 complain);
30430 }
30432 /* Add copy guide. */
30433 {
30436 complain);
30438 }
30441 }
30445 /* Return the non-aggregate deduction guides for deducible template TMPL. The
30446 aggregate candidate is added separately because it depends on the
30447 initializer. Set ANY_DGUIDES_P if we find a non-implicit deduction
30448 guide. */
30450 static tree
30452 {
30455 {
30459 complain);
30460 }
30461 else
30462 {
30468 else
30470 }
30472 /* Cache the deduction guides for a template. We also remember the result of
30473 lookup, and rebuild everything if it changes; should be very rare. */
30477 {
30481 }
30482 else
30483 {
30486 }
30491 else
30492 {
30496 }
30500 }
30502 /* Return whether TMPL is a (class template argument-) deducible template. */
30504 bool
30506 {
30507 /* A deducible template is either a class template or is an alias template
30508 whose defining-type-id is of the form
30510 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
30512 where the nested-name-specifier (if any) is non-dependent and the
30513 template-name of the simple-template-id names a deducible template. */
30524 }
30526 /* Deduce template arguments for the class template placeholder PTYPE for
30527 template TMPL based on the initializer INIT, and return the resulting
30528 type. */
30530 static tree
30533 {
30534 /* We should have handled this in the caller. */
30538 /* If the class was erroneous, don't try to deduce, because that
30539 can generate a lot of diagnostic. */
30545 /* Wait until the enclosing scope is non-dependent. */
30550 /* Initializing one placeholder from another. */
30561 {
30565 }
30567 {
30569 {
30570 /* Be permissive with equivalent alias templates. */
30573 bool complained
30575 "alias template deduction only available "
30580 {
30583 }
30584 }
30585 else
30587 }
30589 /* Wait until the initializer is non-dependent. */
30593 /* Don't bother with the alias rules for an equivalent template. */
30606 {
30611 {
30612 /* As an exception, the first phase in 16.3.1.7 (considering the
30613 initializer list as a single argument) is omitted if the
30614 initializer list consists of a single expression of type cv U,
30615 where U is a specialization of C or a class derived from a
30616 specialization of C. */
30620 }
30623 else
30625 }
30628 else
30631 /* Do this now to avoid problems with erroneous args later on. */
30641 /* Prune explicit deduction guides in copy-initialization context (but
30642 not copy-list-initialization). */
30645 {
30651 {
30652 /* Found a nonconverting guide, prune the candidates. */
30659 }
30660 }
30668 /* If this is list-initialization and the class has a list guide, first
30669 try deducing from the list as a single argument, as [over.match.list]. */
30671 {
30679 {
30680 /* That didn't work, now try treating the list as a sequence of
30681 arguments. */
30687 }
30688 }
30691 {
30693 " of %qT, as it has no non-explicit deduction guides or "
30696 }
30698 {
30702 }
30708 {
30710 {
30716 }
30718 }
30719 /* [over.match.list]/1: In copy-list-initialization, if an explicit
30720 constructor is chosen, the initialization is ill-formed. */
30722 {
30724 {
30726 {
30727 // TODO: Pass down location from cp_finish_decl.
30729 "explicit deduction guide selected in "
30734 }
30736 }
30737 }
30739 /* If CTAD succeeded but the type doesn't have any explicit deduction
30740 guides, this deduction might not be what the user intended. */
30742 {
30746 "%qT may not intend to support class template argument "
30750 }
30754 }
30756 /* Return true if INIT is an unparenthesized id-expression or an
30757 unparenthesized class member access. Used for the argument of
30758 decltype(auto). */
30760 bool
30762 {
30765 /* We need to be able to tell '(r)' and 'r' apart (when it's of
30766 reference type). Only the latter is an id-expression. */
30774 }
30776 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
30777 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
30778 The CONTEXT determines the context in which auto deduction is performed
30779 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
30781 OUTER_TARGS is used during template argument deduction (context == adc_unify)
30782 to properly substitute the result. It's also used in the adc_unify and
30783 adc_requirement contexts to communicate the necessary template arguments
30784 to satisfaction. OUTER_TARGS is ignored in other contexts.
30786 Additionally for adc_unify contexts TMPL is the template for which TYPE
30787 is a template parameter type.
30789 For partial-concept-ids, extra args from OUTER_TARGS, TMPL and the current
30790 scope may be appended to the list of deduced template arguments prior to
30791 determining constraint satisfaction as appropriate. */
30793 tree
30800 {
30806 /* Defining a subset of type-dependent expressions that we can deduce
30807 from ahead of time isn't worth the trouble. */
30810 /* Similarly, we can't deduce from another undeduced decl. */
30814 /* We may be doing a partial substitution, but we still want to replace
30815 auto_node. */
30819 {
30820 /* We don't recurse here because we can't deduce from a nested
30821 initializer_list. */
30825 }
30829 /* In C++23, we must deduce the type to int&& for code like
30830 decltype(auto) f(int&& x) { return (x); }
30831 or
30832 auto&& f(int x) { return x; }
30833 so we use treat_lvalue_as_rvalue_p. But don't do it for
30834 decltype(auto) f(int x) { return x; }
30835 where we should deduce 'int' rather than 'int&&'; transmogrifying
30836 INIT to an rvalue would break that. */
30837 tree r;
30847 /* C++17 class template argument deduction. */
30851 /* Nothing we can do with this, even in deduction context. */
30856 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
30857 with either a new invented type template parameter U or, if the
30858 initializer is a braced-init-list (8.5.4), with
30859 std::initializer_list<U>. */
30861 {
30866 else
30867 {
30869 {
30873 "for deduction to %<std::initializer_list%>, use copy-"
30875 }
30877 }
30878 }
30883 tree targs;
30887 {
30888 /* [dcl.struct.bind]/1 - if decomposition declaration has no ref-qualifiers
30889 and initializer has array type, deduce cv-qualified array type. */
30892 }
30894 {
30902 }
30903 else
30904 {
30909 tree tparms;
30913 else
30914 {
30918 }
30922 DEDUCE_CALL,
30925 {
30927 /* Try again at instantiation time. */
30931 /* If type is error_mark_node a diagnostic must have been
30932 emitted by now. Also, having a mention to '<type error>'
30933 in the diagnostic is not really useful to the user. */
30934 {
30937 && (auto_node
30941 init);
30942 else
30945 DEDUCE_CALL,
30947 }
30949 }
30950 }
30952 /* Check any placeholder constraints against the deduced type. */
30956 {
30958 {
30963 /* If the constraint is dependent, we need to wait until
30964 instantiation time to resolve the placeholder. */
30967 }
30974 {
30978 {
30979 /* As in satisfy_declaration_constraints. */
30983 else
30985 }
30986 }
30993 /* HACK: Compensate for callers not always communicating all levels of
30994 outer template arguments by filling in the outermost missing levels
30995 with dummy levels before checking satisfaction. We'll still crash
30996 if the constraint depends on a template argument belonging to one of
30997 these missing levels, but this hack otherwise allows us to handle a
30998 large subset of possible constraints (including all non-dependent
30999 constraints). */
31002 {
31007 }
31010 {
31012 {
31013 auto_diagnostic_group d;
31015 {
31033 }
31035 }
31037 }
31038 }
31041 /* The outer template arguments are already substituted into type
31048 }
31050 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
31051 result. */
31053 tree
31055 {
31057 {
31060 }
31064 {
31065 /* In an abbreviated function template we didn't know we were dealing
31066 with a function template when we saw the auto return type, so rebuild
31067 the return type using an auto with the correct level. */
31072 auto_vec);
31073 /* Also rebuild the constraint info in terms of the new auto. */
31081 }
31083 }
31085 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
31086 'decltype(auto)' or a deduced class template. */
31088 bool
31090 {
31095 else
31097 }
31099 /* for_each_template_parm callback for type_uses_auto. */
31101 int
31103 {
31105 }
31107 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
31108 a use of `auto'. Returns NULL_TREE otherwise. */
31110 tree
31112 {
31116 {
31117 /* The Concepts TS allows multiple autos in one type-specifier; just
31118 return the first one we find, do_auto_deduction will collect all of
31119 them. */
31123 else
31125 }
31126 else
31128 }
31130 /* Report ill-formed occurrences of auto types in ARGUMENTS. If
31131 concepts are enabled, auto is acceptable in template arguments, but
31132 only when TEMPL identifies a template class. Return TRUE if any
31133 such errors were reported. */
31135 bool
31137 {
31139 /* Only the concepts TS allows 'auto' as a type-id; it'd otherwise
31140 have already been rejected by the parser more generally. */
31143 /* If there were previous errors, nevermind. */
31147 /* If TMPL is an identifier, we're parsing and we can't tell yet
31148 whether TMPL is supposed to be a type, a function or a variable.
31149 We'll only be able to tell during template substitution, so we
31150 expect to be called again then. If concepts are enabled and we
31151 know we have a type, we're ok. */
31158 /* Quickly search for any occurrences of auto; usually there won't
31159 be any, and then we'll avoid allocating the vector. */
31167 {
31172 }
31175 }
31177 /* Recursively walk over && expressions searching for EXPR. Return a reference
31178 to that expression. */
31181 {
31185 {
31190 }
31192 }
31194 /* Convert the generic type parameters in PARM that match the types given in the
31195 range [START_IDX, END_IDX) from the current_template_parms into generic type
31196 packs. */
31198 tree
31200 {
31211 {
31212 /* Create a distinct parameter pack type from the current parm and add it
31213 to the replacement args to tsubst below into the generic function
31214 parameter. */
31228 /* Replace the current template parameter with new pack. */
31231 /* Surgically adjust the associated constraint of adjusted parameter
31232 and it's corresponding contribution to the current template
31233 requirements. */
31235 {
31241 /* If there was a constraint, we also need to replace that in
31242 the template requirements, which we've already built. */
31246 }
31247 }
31253 /* If there are more levels then build up the replacement with the outer
31254 template parms. */
31258 replacement);
31261 }
31263 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
31264 0..N-1. */
31266 void
31268 {
31271 integer_type_node,
31272 NULL_TREE),
31276 CP_BUILT_IN_INTEGER_PACK);
31277 }
31279 /* Walk the decl or type specialization table calling FN on each
31280 entry. */
31282 void
31286 {
31292 }
31294 /* Lookup the specialization of *ELT, in the decl or type
31295 specialization table. Return the SPEC that's already there, or
31296 NULL if nothing. */
31298 tree
31300 {
31310 }
31312 /* Return flags encoding whether SPEC is on the instantiation and/or
31313 specialization lists of TMPL. */
31315 unsigned
31317 {
31323 {
31326 }
31331 /* Only need to search if DECL is a partial specialization. */
31335 {
31338 }
31341 }
31343 /* Add a new specialization described by SPEC. DECL is the
31344 maybe-template decl and FLAGS is as returned from
31345 get_mergeable_specialization_flags. */
31347 void
31350 {
31353 {
31362 {
31365 }
31366 }
31369 {
31372 /* We don't distinguish different constrained partial type
31373 specializations, so there could be duplicates. Everything else
31374 must be new. */
31376 {
31382 }
31383 }
31390 {
31391 /* A partial specialization. */
31396 }
31397 }
31399 /* Set up the hash tables for template instantiations. */
31401 void
31403 {
31409 }
31411 /* Print stats about the template hash tables for -fstats. */
31413 void
31415 {
31424 }
31426 #if CHECKING_P
31430 /* Verify that build_non_dependent_expr () works, for various expressions,
31431 and that location wrappers don't affect the results. */
31433 static void
31435 {
31438 /* Verify constants, without and with location wrappers. */
31455 }
31457 /* Verify that type_dependent_expression_p () works correctly, even
31458 in the presence of location wrapper nodes. */
31460 static void
31462 {
31467 /* If no templates are involved, nothing is type-dependent. */
31473 /* Within a template, an unresolved name is always type-dependent. */
31476 /* Ensure it copes with NULL_TREE and errors. */
31480 /* A USING_DECL in a template should be type-dependent, even if wrapped
31481 with a location wrapper (PR c++/83799). */
31490 }
31492 /* Run all of the selftests within this file. */
31494 void
31496 {
31499 }