| blob | c017591f235b30ff202748c8dc954437452ecf3d |
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 {
4580 }
4582 /* Attach the TPI to the decl. */
4585 else
4587 }
4590 }
4592 /* Process information from new template parameter PARM and append it
4593 to the LIST being built. This new parameter is a non-type
4594 parameter iff IS_NON_TYPE is true. This new parameter is a
4595 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4596 is in PARM_LOC. */
4598 tree
4601 {
4607 {
4617 }
4624 {
4630 {
4631 /* [temp.param]
4633 The top-level cv-qualifiers on the template-parameter are
4634 ignored when determining its type. */
4639 && !is_parameter_pack
4640 /* If we're in a nested template parameter list, the template
4641 template parameter could be a parameter pack. */
4643 {
4644 /* This template parameter is not a parameter pack, but it
4645 should be. Complain about "bare" parameter packs. */
4648 /* Recover by calling this a parameter pack. */
4650 }
4651 }
4653 /* A template parameter is not modifiable. */
4662 current_template_depth,
4667 }
4668 else
4669 {
4670 tree t;
4674 {
4676 /* This is for distinguishing between real templates and template
4677 template parameters */
4680 /* any_template_parm_r expects to be able to get the targs of a
4681 DECL_TEMPLATE_RESULT. */
4690 }
4691 else
4692 {
4694 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4697 }
4704 current_template_depth,
4708 }
4716 /* Build requirements for the type/template parameter.
4717 This must be done after SET_DECL_TEMPLATE_PARM_P or
4718 process_template_parm could fail. */
4725 /* Build the parameter node linking the parameter declaration,
4726 its default argument (if any), and its constraints (if any). */
4732 else
4736 }
4738 /* The end of a template parameter list has been reached. Process the
4739 tree list into a parameter vector, converting each parameter into a more
4740 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4741 as PARM_DECLs. */
4743 tree
4745 {
4748 /* Pop the dummy parameter level and add the real one. We do not
4749 morph the dummy parameter in place, as it might have been
4750 captured by a (nested) template-template-parm. */
4753 current_template_parms
4758 {
4764 }
4769 }
4771 // Explicitly indicate the end of the template parameter list. We assume
4772 // that the current template parameters have been constructed and/or
4773 // managed explicitly, as when creating new template template parameters
4774 // from a shorthand constraint.
4775 void
4777 {
4779 }
4781 /* end_template_decl is called after a template declaration is seen. */
4783 void
4785 {
4791 /* This matches the pushlevel in begin_template_parm_list. */
4796 }
4798 /* Takes a TEMPLATE_PARM_P or DECL_TEMPLATE_PARM_P node or a TREE_LIST
4799 thereof, and converts it into an argument suitable to be passed to
4800 the type substitution functions. Note that if the TREE_LIST contains
4801 an error_mark node, the returned argument is error_mark_node. */
4803 tree
4805 {
4816 {
4820 else
4822 }
4828 {
4830 {
4831 /* Turn this argument into a TYPE_ARGUMENT_PACK
4832 with a single element, which expands T. */
4841 }
4842 }
4843 else
4844 {
4846 {
4847 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4848 with a single element, which expands T. */
4858 }
4859 else
4861 }
4863 }
4865 /* If T looks like a generic template argument produced by template_parm_to_arg,
4866 return the corresponding template parameter, otherwise return NULL_TREE. */
4868 static tree
4870 {
4875 {
4880 }
4887 else
4889 }
4891 /* Given a single level of template parameters (a TREE_VEC), return it
4892 as a set of template arguments. */
4894 tree
4896 {
4906 }
4908 /* Given a set of template parameters, return them as a set of template
4909 arguments. The template parameters are represented as a TREE_VEC, in
4910 the form documented in cp-tree.h for template arguments. */
4912 tree
4914 {
4915 tree header;
4920 /* If there is only one level of template parameters, we do not
4921 create a TREE_VEC of TREE_VECs. Instead, we return a single
4922 TREE_VEC containing the arguments. */
4927 {
4932 else
4934 }
4937 }
4939 /* Within the declaration of a template, return the currently active
4940 template parameters as an argument TREE_VEC. */
4942 static tree
4944 {
4946 }
4948 /* Return the fully generic arguments for of TMPL, i.e. what
4949 current_template_args would be while parsing it. */
4951 tree
4953 {
4958 /* DECL_TEMPLATE_RESULT doesn't have the arguments we want. For a template
4959 template parameter, it has no TEMPLATE_INFO; for a partial
4960 specialization, it has the arguments for the primary template, and we
4966 }
4968 /* Return the template arguments corresponding to the template parameters of
4969 DECL's enclosing scope. When DECL is a member of a partial specialization,
4970 this returns the arguments for the partial specialization as opposed to those
4971 for the primary template, which is the main difference between this function
4972 and simply using e.g. the TYPE_TI_ARGS of DECL's DECL_CONTEXT. */
4974 tree
4976 {
4988 }
4990 /* Update the declared TYPE by doing any lookups which were thought to be
4991 dependent, but are not now that we know the SCOPE of the declarator. */
4993 tree
4995 {
5006 /* Don't bother building up the args in this case. */
5008 {
5009 /* tsubst in the args corresponding to the template parameters,
5010 including auto if present. Most things will be unchanged, but
5011 make_typename_type and tsubst_qualified_id will resolve
5012 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
5015 tree pushed;
5017 {
5021 }
5026 }
5032 {
5035 else
5037 }
5039 }
5041 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
5042 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
5043 the new template is a member template. */
5045 static tree
5047 {
5059 /* Propagate module information from the decl. */
5063 }
5065 struct template_parm_data
5066 {
5067 /* The level of the template parameters we are currently
5068 processing. */
5071 /* The index of the specialization argument we are currently
5072 processing. */
5075 /* An array whose size is the number of template parameters. The
5076 elements are nonzero if the parameter has been used in any one
5077 of the arguments processed so far. */
5080 /* An array whose size is the number of template arguments. The
5081 elements are nonzero if the argument makes use of template
5082 parameters of this level. */
5084 };
5086 /* Subroutine of push_template_decl used to see if each template
5087 parameter in a partial specialization is used in the explicit
5088 argument list. If T is of the LEVEL given in DATA (which is
5089 treated as a template_parm_data*), then DATA->PARMS is marked
5090 appropriately. */
5092 static int
5094 {
5102 {
5105 }
5107 /* In C++17 the type of a non-type argument is a deduced context. */
5112 data,
5113 NULL,
5116 /* Return zero so that for_each_template_parm will continue the
5117 traversal of the tree; we want to mark *every* template parm. */
5119 }
5121 /* Process the partial specialization DECL. */
5123 static tree
5125 {
5132 tree inner_parms;
5133 tree inst;
5143 /* A concept cannot be specialized. */
5145 {
5148 }
5153 /* We check that each of the template parameters given in the
5154 partial specialization is used in the argument list to the
5155 specialization. For example:
5157 template <class T> struct S;
5158 template <class T> struct S<T*>;
5160 The second declaration is OK because `T*' uses the template
5161 parameter T, whereas
5163 template <class T> struct S<int>;
5165 is no good. Even trickier is:
5167 template <class T>
5168 struct S1
5169 {
5170 template <class U>
5171 struct S2;
5172 template <class U>
5173 struct S2<T>;
5174 };
5176 The S2<T> declaration is actually invalid; it is a
5177 full-specialization. Of course,
5179 template <class U>
5180 struct S2<T (*)(U)>;
5182 or some such would have been OK. */
5190 {
5195 NULL,
5197 }
5200 {
5201 /* One of the template parms was not used in a deduced context in the
5202 specialization. */
5204 {
5208 }
5212 }
5217 /* [temp.class.spec]
5219 The argument list of the specialization shall not be identical to
5220 the implicit argument list of the primary template. */
5221 tree main_args
5224 && (!flag_concepts
5226 {
5229 "any template arguments; to define the primary template, "
5231 else
5233 "template arguments and is not more constrained than "
5234 "the primary template; to define the primary template, "
5237 }
5239 /* A partial specialization that replaces multiple parameters of the
5240 primary template with a pack expansion is less specialized for those
5241 parameters. */
5243 {
5245 "primary template because it replaces multiple parameters "
5248 /* Avoid crash in process_partial_specialization. */
5250 }
5253 {
5256 /* Avoid crash below. */
5258 }
5260 /* If we aren't in a dependent class, we can actually try deduction. */
5262 /* FIXME we should be able to handle a partial specialization of a
5263 partial instantiation, but currently we can't (c++/41727). */
5266 {
5267 auto_diagnostic_group d;
5270 decl))
5272 maintmpl);
5273 }
5275 /* [temp.spec.partial]
5277 The type of a template parameter corresponding to a specialized
5278 non-type argument shall not be dependent on a parameter of the
5279 specialization.
5281 Also, we verify that pack expansions only occur at the
5282 end of the argument list. */
5285 {
5292 {
5293 /* Extract the arguments from the argument pack. We'll be
5294 iterating over these in the following loop. */
5297 }
5300 {
5302 /* Get the Jth argument in the parameter pack. */
5306 {
5307 /* Pack expansions must come at the end of the
5308 argument list. */
5311 {
5315 else
5318 }
5319 }
5322 /* We only care about the pattern. */
5328 /* This next two lines are the `argument expression is not just a
5329 simple identifier' condition and also the `specialized
5330 non-type argument' bit. */
5335 {
5336 /* Look at the corresponding template parameter,
5337 marking which template parameters its type depends
5338 upon. */
5342 {
5343 /* We haven't yet initialized TPD2. Do so now. */
5345 /* The number of parameters here is the number in the
5346 main template, which, as checked in the assertion
5347 above, is NARGS. */
5351 }
5353 /* Mark the template parameters. But this time, we're
5354 looking for the template parameters of the main
5355 template, not in the specialization. */
5362 NULL,
5366 {
5367 /* The type depended on some template parameters.
5368 If they are fully specialized in the
5369 specialization, that's OK. */
5378 "type %qT of template argument %qE depends "
5380 "type %qT of template argument %qE depends "
5382 type,
5383 arg);
5384 }
5385 }
5386 }
5387 }
5389 /* We should only get here once. */
5393 // Build the template decl.
5400 /* Give template template parms a DECL_CONTEXT of the template
5401 for which they are a parameter. */
5403 {
5407 }
5410 /* We didn't register this in check_explicit_specialization so we could
5411 wait until the constraints were set. */
5413 else
5420 /* Link the DECL_TEMPLATE_RESULT back to the partial TEMPLATE_DECL. */
5426 {
5432 {
5441 "declaration of %qD ambiguates earlier template "
5445 "partial specialization of %qD after instantiation "
5447 }
5448 }
5451 }
5453 /* PARM is a template parameter of some form; return the corresponding
5454 TEMPLATE_PARM_INDEX. */
5456 static tree
5458 {
5471 }
5473 /* Subroutine of fixed_parameter_pack_p below. Look for any template
5474 parameter packs used by the template parameter PARM. */
5476 static void
5478 {
5479 /* A type parm can't refer to another parm. */
5483 {
5487 }
5493 {
5497 else
5499 }
5500 }
5502 /* PARM is a template parameter pack. Return any parameter packs used in
5503 its type or the type of any of its template parameters. If there are
5504 any such packs, it will be instantiated into a fixed template parameter
5505 list by partial instantiation rather than be fully deduced. */
5507 tree
5509 {
5510 /* This can only be true in a member template. */
5513 /* This can only be true for a parameter pack. */
5516 /* A type parm can't refer to another parm. */
5530 }
5532 /* Check that a template declaration's use of default arguments and
5533 parameter packs is not invalid. Here, PARMS are the template
5534 parameters. IS_PRIMARY is true if DECL is the thing declared by
5535 a primary template. IS_PARTIAL is true if DECL is a partial
5536 specialization.
5538 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
5539 function template declaration or a friend class template
5540 declaration. In the function case, 1 indicates a declaration, 2
5541 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
5542 emitted for extraneous default arguments.
5544 Returns TRUE if there were no errors found, FALSE otherwise. */
5546 bool
5549 {
5552 tree parm_level;
5555 /* [temp.param]
5557 A default template-argument shall not be specified in a
5558 function template declaration or a function template definition, nor
5559 in the template-parameter-list of the definition of a member of a
5560 class template. */
5564 /* You can't have a function template declaration in a local
5565 scope, nor you can you define a member of a class template in a
5566 local scope. */
5574 /* A lambda doesn't have an explicit declaration; don't complain
5575 about the parms of the enclosing class. */
5582 /* If this is either a friend defined in the scope of the class
5583 or a member function. */
5589 /* And, if it was a member function, it really was defined in
5590 the scope of the class. */
5593 /* We already checked these parameters when the template was
5594 declared, so there's no need to do it again now. This function
5595 was defined in class scope, but we're processing its body now
5596 that the class is complete. */
5599 /* Core issue 226 (C++0x only): the following only applies to class
5600 templates. */
5603 {
5604 /* [temp.param]
5606 If a template-parameter has a default template-argument, all
5607 subsequent template-parameters shall have a default
5608 template-argument supplied. */
5610 {
5617 {
5627 {
5629 /* For better subsequent error-recovery, we indicate that
5630 there should have been a default argument. */
5633 }
5635 && !is_friend_decl
5636 /* Don't complain about an enclosing partial
5637 specialization. */
5642 /* A fixed parameter pack will be partially
5643 instantiated into a fixed length list. */
5645 {
5646 /* A primary class template, primary variable template
5647 (DR 2032), or alias template can only have one
5648 parameter pack, at the end of the template
5649 parameter list. */
5657 }
5658 }
5659 }
5660 }
5663 || is_partial
5664 || !is_primary
5666 /* For an ordinary class template, default template arguments are
5667 allowed at the innermost level, e.g.:
5668 template <class T = int>
5669 struct S {};
5670 but, in a partial specialization, they're not allowed even
5671 there, as we have in [temp.class.spec]:
5673 The template parameter list of a specialization shall not
5674 contain default template argument values.
5676 So, for a partial specialization, or for a function template
5677 (in C++98/C++03), we look at all of them. */
5678 ;
5679 else
5680 /* But, for a primary class template that is not a partial
5681 specialization we look at all template parameters except the
5682 innermost ones. */
5685 /* Figure out what error message to issue. */
5700 else
5701 /* Per [temp.param]/9, "A default template-argument shall not be
5702 specified in the template-parameter-lists of the definition of
5703 a member of a class template that appears outside of the member's
5704 class.", thus if we aren't handling a member of a class template
5705 there is no need to examine the parameters. */
5709 /* If we're inside a class definition, there's no need to
5710 examine the parameters to the class itself. On the one
5711 hand, they will be checked when the class is defined, and,
5712 on the other, default arguments are valid in things like:
5713 template <class T = double>
5714 struct S { template <class U> void f(U); };
5715 Here the default argument for `S' has no bearing on the
5716 declaration of `f'. */
5718 else
5719 /* Check everything. */
5725 {
5732 {
5737 {
5739 {
5746 }
5748 /* Clear out the default argument so that we are not
5749 confused later. */
5751 }
5752 }
5754 /* At this point, if we're still interested in issuing messages,
5755 they must apply to classes surrounding the object declared. */
5759 }
5762 }
5764 /* Worker for push_template_decl_real, called via
5765 for_each_template_parm. DATA is really an int, indicating the
5766 level of the parameters we are interested in. If T is a template
5767 parameter of that level, return nonzero. */
5769 static int
5771 {
5777 else
5780 }
5782 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5783 DATA is really an int, indicating the innermost outer level of parameters.
5784 If T is a template parameter of that level or further out, return
5785 nonzero. */
5787 static int
5789 {
5795 else
5798 }
5800 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5801 parameters given by current_template_args, or reuses a
5802 previously existing one, if appropriate. Returns the DECL, or an
5803 equivalent one, if it is replaced via a call to duplicate_decls.
5805 If IS_FRIEND is true, DECL is a friend declaration. */
5807 tree
5809 {
5813 /* See if this is a partial specialization. */
5822 /* No surprising friend functions. */
5827 tree ctx;
5829 /* For a friend, we want the context of the friend, not
5830 the type of which it is a friend. */
5834 /* In the case of a virtual function, we want the class in which
5835 it is defined. */
5837 else
5838 /* Otherwise, if we're currently defining some class, the DECL
5839 is assumed to be a member of the class. */
5848 /* See if this is a primary template. */
5852 /* A friend template that specifies a class context, i.e.
5853 template <typename T> friend void A<T>::f();
5854 is not primary. */
5855 ;
5857 /* Lambdas are not primary. */
5858 ;
5859 else
5862 /* True if the template is a member template, in the sense of
5863 [temp.mem]. */
5867 {
5875 {
5878 }
5880 {
5882 {
5885 }
5887 {
5888 /* [temp.mem]
5890 A destructor shall not be a member template. */
5894 }
5901 {
5902 /* [basic.stc.dynamic.allocation]
5904 An allocation function can be a function
5905 template. ... Template allocation functions shall
5906 have two or more parameters. */
5909 }
5910 }
5916 /* alias-declaration */
5922 else
5923 {
5926 }
5927 }
5934 /* Check to see that the rules regarding the use of default
5935 arguments are not being violated. We check args for a friend
5936 functions when we know whether it's a definition, introducing
5937 declaration or re-declaration. */
5942 /* Ensure that there are no parameter packs in the type of this
5943 declaration that have not been expanded. */
5945 {
5946 /* Check each of the arguments individually to see if there are
5947 any bare parameter packs. */
5953 {
5956 {
5957 /* This is a PARM_DECL that contains unexpanded parameter
5958 packs. We have already complained about this in the
5959 check_for_bare_parameter_packs call, so just replace
5960 these types with ERROR_MARK_NODE. */
5963 }
5967 }
5969 /* Check for bare parameter packs in the return type and the
5970 exception specifiers. */
5972 /* Errors were already issued, set return type to int
5973 as the frontend doesn't expect error_mark_node as
5974 the return type. */
5978 }
5979 else
5980 {
5984 {
5987 }
5992 }
6001 {
6002 /* Does not get a template head. */
6005 }
6012 {
6017 /* If DECL is a TYPE_DECL for a class-template, then there won't
6018 be DECL_LANG_SPECIFIC. The information equivalent to
6019 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
6023 {
6024 /* Since a template declaration already existed for this
6025 class-type, we must be redeclaring it here. Make sure
6026 that the redeclaration is valid. */
6028 current_template_parms,
6030 /* We don't need to create a new TEMPLATE_DECL; just use the
6031 one we already had. */
6033 }
6034 else
6035 {
6037 member_template_p);
6042 {
6043 /* A specialization of a member template of a template
6044 class. */
6048 }
6049 }
6050 }
6051 else
6052 {
6058 {
6061 }
6069 {
6070 /* The declaration is a specialization of a member
6071 template, declared outside the class. Therefore, the
6072 innermost template arguments will be NULL, so we
6073 replace them with the arguments determined by the
6074 earlier call to check_explicit_specialization. */
6077 tree new_tmpl
6079 member_template_p);
6087 args,
6090 }
6092 /* Make sure the template headers we got make sense. */
6097 {
6102 }
6103 else
6105 {
6110 {
6114 else
6118 /* Avoid crash in import_export_decl. */
6121 }
6126 /* Can happen in erroneous input. */
6128 else
6130 }
6132 /* Check that the parms are used in the appropriate qualifying scopes
6133 in the declarator. */
6137 {
6143 /* Avoid crash in import_export_decl. */
6146 }
6148 /* Check that the constraints for each enclosing template scope are
6149 consistent with the original declarations. */
6151 {
6155 {
6158 }
6160 {
6162 {
6166 }
6169 }
6170 }
6171 }
6176 {
6177 /* Push template declarations for global functions and types.
6178 Note that we do not try to push a global template friend
6179 declared in a template class; such a thing may well depend on
6180 the template parameters of the class and we'll push it when
6181 instantiating the befriending class. */
6184 {
6189 /* pushdecl may have found an existing template. */
6191 {
6194 }
6195 }
6197 {
6198 /* Record this decl as belonging to the current class. It's
6199 not chained onto anything else. */
6203 }
6204 }
6206 /* The type may have been completed, or (erroneously) changed. */
6210 {
6212 {
6217 /* Give template template parms a DECL_CONTEXT of the template
6218 for which they are a parameter. */
6221 {
6225 }
6229 {
6232 {
6233 /* ??? Why don't we do this here for all templates? */
6236 }
6239 }
6240 }
6242 /* The DECL_TI_ARGS of DECL contains full set of arguments
6243 referring wback to its most general template. If TMPL is a
6244 specialization, ARGS may only have the innermost set of
6245 arguments. Add the missing argument levels if necessary. */
6253 else
6254 {
6257 }
6258 }
6261 && !is_friend
6264 /* Set DECL_COMDAT on template instantiations; if we force
6265 them to be emitted by explicit instantiation,
6266 mark_needed will tell cgraph to do the right thing. */
6272 }
6274 /* FN is an inheriting constructor that inherits from the constructor
6275 template INHERITED; turn FN into a constructor template with a matching
6276 template header. */
6278 tree
6280 {
6281 tree inner_parms
6284 tree parms
6293 }
6295 /* Called when a class template TYPE is redeclared with the indicated
6296 template PARMS, e.g.:
6298 template <class T> struct S;
6299 template <class T> struct S {}; */
6301 bool
6303 {
6304 tree tmpl;
6305 tree tmpl_parms;
6309 {
6312 }
6316 /* The type is nested in some template class. Nothing to worry
6317 about here; there are no new template parameters for the nested
6318 type. */
6322 {
6324 tmpl);
6326 }
6332 {
6342 }
6345 {
6346 tree tmpl_parm;
6347 tree parm;
6359 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
6360 TEMPLATE_DECL. */
6370 {
6371 auto_diagnostic_group d;
6375 else
6378 }
6380 /* The parameters can be declared to introduce different
6381 constraints. */
6385 {
6386 auto_diagnostic_group d;
6392 }
6394 /* Give each template template parm in this redeclaration a
6395 DECL_CONTEXT of the template for which they are a parameter. */
6397 {
6401 }
6402 }
6411 /* Two classes with different constraints declare different entities. */
6413 {
6414 auto_diagnostic_group d;
6420 }
6423 }
6425 /* The actual substitution part of instantiate_non_dependent_expr,
6426 to be used when the caller has already checked
6427 !instantiation_dependent_uneval_expression_p (expr)
6428 and cleared processing_template_decl. */
6430 tree
6432 {
6435 complain,
6437 }
6439 /* Instantiate the non-dependent expression EXPR. */
6441 tree
6444 {
6449 {
6450 /* The caller should have checked this already. */
6452 processing_template_decl_sentinel s;
6454 }
6456 }
6458 /* Like instantiate_non_dependent_expr, but return NULL_TREE if the
6459 expression is dependent or non-constant. */
6461 tree
6463 {
6467 {
6470 else
6471 {
6472 processing_template_decl_sentinel s;
6474 }
6475 }
6477 }
6479 /* True iff T is a specialization of a variable template. */
6481 bool
6483 {
6488 }
6490 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
6491 template declaration, or a TYPE_DECL for an alias declaration. */
6493 bool
6495 {
6503 }
6505 /* If T is a specialization of an alias template, return it; otherwise return
6506 NULL_TREE. If TRANSPARENT_TYPEDEFS is true, look through other aliases. */
6508 tree
6511 {
6515 /* It's an alias template specialization if it's an alias and its
6516 TYPE_NAME is a specialization of a primary template. */
6518 {
6525 transparent_typedefs);
6526 }
6529 }
6531 /* Data structure for complex_alias_template_*. */
6533 struct uses_all_template_parms_data
6534 {
6537 };
6539 /* walk_tree callback for complex_alias_template_p. */
6541 static tree
6543 {
6548 {
6553 {
6557 }
6560 }
6565 /* An alias template with a pack expansion that expands a pack from the
6566 enclosing class needs to be considered complex, to avoid confusion with
6567 the same pack being used as an argument to the alias's own template
6568 parameter (91966). */
6571 {
6580 /* Consider the expanded packs to be used outside the expansion... */
6582 }
6584 /* ...but don't walk into the pattern. Consider PR104008:
6586 template <typename T, typename... Ts>
6587 using IsOneOf = disjunction<is_same<T, Ts>...>;
6589 where IsOneOf seemingly uses all of its template parameters in its
6590 expansion (and does not expand a pack from the enclosing class), so the
6591 alias was not marked as complex. However, if it is used like
6592 "IsOneOf<T>", the empty pack for Ts means that T no longer appears in the
6593 expansion. So only Ts is considered used by the pack expansion. */
6597 }
6599 /* An alias template is complex from a SFINAE perspective if a template-id
6600 using that alias can be ill-formed when the expansion is not, as with
6601 the void_t template.
6603 Returns 1 if always complex, 0 if not complex, -1 if complex iff any of the
6604 template arguments are empty packs. */
6606 static bool
6608 {
6609 /* A renaming alias isn't complex. */
6613 /* Any other constrained alias is complex. */
6632 }
6634 /* If T is a specialization of a complex alias template with dependent
6635 template-arguments, return it; otherwise return NULL_TREE. If T is a
6636 typedef to such a specialization, return the specialization. */
6638 tree
6640 {
6651 && (any_dependent_template_arguments_p
6656 {
6659 }
6662 }
6664 /* Return the number of innermost template parameters in TMPL. */
6666 static int
6668 {
6671 }
6673 /* Return either TMPL or another template that it is equivalent to under DR
6674 1286: An alias that just changes the name of a template is equivalent to
6675 the other template. */
6677 static tree
6679 {
6682 {
6683 /* Determine if the alias is equivalent to an underlying template. */
6685 /* The underlying type may have been ill-formed. Don't proceed. */
6698 /* Does the alias add cv-quals? */
6706 /* Are any default template arguments equivalent? */
6711 {
6716 }
6718 /* If TMPL adds or changes any constraints, it isn't equivalent. I think
6719 it's appropriate to treat a less-constrained alias as equivalent. */
6723 /* Alias is equivalent. Strip it and repeat. */
6725 }
6726 top_break:;
6729 }
6731 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6732 must be a reference-to-function or a pointer-to-function type, as specified
6733 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6734 and check that the resulting function has external linkage. */
6736 static tree
6738 tsubst_flags_t complain)
6739 {
6742 linkage_kind linkage;
6760 /* [temp.arg.nontype]/1
6762 A template-argument for a non-type, non-template template-parameter
6763 shall be one of:
6764 [...]
6765 -- the address of an object or function with external [C++11: or
6766 internal] linkage. */
6770 {
6772 {
6779 else
6782 }
6784 }
6789 {
6791 {
6797 else
6801 }
6803 }
6805 accept:
6807 {
6810 else
6812 }
6817 }
6819 /* Subroutine of convert_nontype_argument.
6820 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6821 Emit an error otherwise. */
6823 static bool
6825 tsubst_flags_t complain)
6826 {
6842 {
6848 else
6850 }
6852 }
6854 /* Returns TRUE iff the address of OP is value-dependent.
6856 14.6.2.4 [temp.dep.temp]:
6857 A non-integral non-type template-argument is dependent if its type is
6858 dependent or it has either of the following forms
6859 qualified-id
6860 & qualified-id
6861 and contains a nested-name-specifier which specifies a class-name that
6862 names a dependent type.
6864 We generalize this to just say that the address of a member of a
6865 dependent class is value-dependent; the above doesn't cover the
6866 address of a static data member named with an unqualified-id. */
6868 static bool
6870 {
6873 /* We could use get_inner_reference here, but there's no need;
6874 this is only relevant for template non-type arguments, which
6875 can only be expressed as &id-expression. */
6877 {
6888 }
6891 }
6893 /* The next set of functions are used for providing helpful explanatory
6894 diagnostics for failed overload resolution. Their messages should be
6895 indented by two spaces for consistency with the messages in
6896 call.cc */
6898 static int
6900 {
6902 }
6904 /* Other failure functions should call this one, to provide a single function
6905 for setting a breakpoint on. */
6907 static int
6909 {
6911 }
6913 static int
6915 {
6920 }
6922 static int
6924 {
6930 }
6932 static int
6934 {
6938 }
6940 static int
6942 {
6945 " template parameter %qD is not a parameter pack, but "
6949 }
6951 static int
6953 {
6956 " template argument %qE does not match "
6960 }
6962 static int
6964 {
6968 }
6970 static int
6972 {
6978 }
6980 static int
6982 {
6984 {
6989 else
6991 " deduced conflicting values for non-type parameter "
6993 }
6995 }
6997 static int
6999 {
7002 " variable-sized array type %qT is not "
7004 arg);
7006 }
7008 static int
7010 {
7014 arg);
7016 }
7018 static int
7020 {
7022 {
7028 else
7033 }
7035 }
7037 static int
7039 {
7041 }
7043 static int
7046 {
7048 }
7050 static int
7053 {
7059 }
7061 static int
7064 {
7067 {
7075 }
7077 }
7079 static int
7081 {
7084 " template parameters of a template template argument are "
7087 }
7089 static int
7091 {
7097 }
7099 static int
7101 {
7106 }
7108 /* Subroutine of convert_nontype_argument, to check whether EXPR, as an
7109 argument for TYPE, points to an unsuitable object.
7111 Also adjust the type of the index in C++20 array subobject references. */
7113 static bool
7115 {
7117 {
7118 CASE_CONVERT:
7120 complain);
7124 complain);
7127 {
7131 }
7135 {
7141 {
7145 /* Canonicalize array offsets to ptrdiff_t; how they were
7146 written doesn't matter for subobject identity. */
7149 }
7152 {
7155 "%qE is not a valid template argument of type %qT "
7159 }
7161 {
7164 "%qE is not a valid template argument of type %qT "
7168 }
7171 {
7174 "%qE is not a valid template argument of type %qT "
7177 }
7178 /* C++17: For a non-type template-parameter of reference or pointer
7179 type, the value of the constant expression shall not refer to (or
7180 for a pointer type, shall not be the address of):
7181 * a subobject (4.5),
7182 * a temporary object (15.2),
7183 * a string literal (5.13.5),
7184 * the result of a typeid expression (8.2.8), or
7185 * a predefined __func__ variable (11.4.1). */
7187 {
7190 decl);
7192 }
7194 && !(same_type_ignoring_top_level_qualifiers_p
7197 {
7202 }
7204 {
7208 decl);
7210 }
7211 }
7219 else
7220 {
7222 {
7225 "because %qD is a variable, not the address of "
7228 }
7229 else
7230 {
7236 }
7237 }
7238 }
7241 }
7243 /* Return a VAR_DECL for the C++20 template parameter object corresponding to
7244 template argument EXPR. */
7246 static tree
7248 {
7253 {
7258 }
7262 /* This is no longer a compound literal. */
7266 }
7268 /* The template arguments corresponding to template parameter objects of types
7269 that contain pointers to members. */
7273 /* Find or build an nttp object for (already-validated) EXPR with name
7274 NAME. */
7276 tree
7278 {
7295 {
7296 /* If EXPR contains any PTRMEM_CST, they will get clobbered by
7297 lower_var_init before we're done mangling. So store the original
7298 value elsewhere. */
7301 }
7306 }
7308 /* Return the actual template argument corresponding to template parameter
7309 object VAR. */
7311 tree
7313 {
7317 }
7319 /* Attempt to convert the non-type template parameter EXPR to the
7320 indicated TYPE. If the conversion is successful, return the
7321 converted value. If the conversion is unsuccessful, return
7322 NULL_TREE if we issued an error message, or error_mark_node if we
7323 did not. We issue error messages for out-and-out bad template
7324 parameters, but not simply because the conversion failed, since we
7325 might be just trying to do argument deduction. Both TYPE and EXPR
7326 must be non-dependent.
7328 The conversion follows the special rules described in
7329 [temp.arg.nontype], and it is much more strict than an implicit
7330 conversion.
7332 This function is called twice for each template argument (see
7333 lookup_template_class for a more accurate description of this
7334 problem). This means that we need to handle expressions which
7335 are not valid in a C++ source, but can be created from the
7336 first call (for instance, casts to perform conversions). These
7337 hacks can go away after we fix the double coercion problem. */
7339 static tree
7341 {
7342 tree expr_type;
7345 /* Detect immediately string literals as invalid non-type argument.
7346 This special-case is not needed for correctness (we would easily
7347 catch this later), but only to provide better diagnostic for this
7348 common user mistake. As suggested by DR 100, we do not mention
7349 linkage issues in the diagnostic as this is not the point. */
7351 {
7357 }
7359 /* Add the ADDR_EXPR now for the benefit of
7360 value_dependent_expression_p. */
7363 {
7367 }
7369 /* If we are in a template, EXPR may be non-dependent, but still
7370 have a syntactic, rather than semantic, form. For example, EXPR
7371 might be a SCOPE_REF, rather than the VAR_DECL to which the
7372 SCOPE_REF refers. Preserving the qualifying scope is necessary
7373 so that access checking can be performed when the template is
7374 instantiated -- but here we need the resolved form so that we can
7375 convert the argument. */
7387 /* If the argument is non-dependent, perform any conversions in
7388 non-dependent context as well. */
7396 else
7399 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
7400 to a non-type argument of "nullptr". */
7404 /* In C++11, integral or enumeration non-type template arguments can be
7405 arbitrary constant expressions. Pointer and pointer to
7406 member arguments can be general constant expressions that evaluate
7407 to a null value, but otherwise still need to be of a specific form. */
7409 {
7411 /* A PTRMEM_CST is already constant, and a valid template
7412 argument for a parameter of pointer to member type, we just want
7413 to leave it in that form rather than lower it to a
7417 {
7418 /* C++17: A template-argument for a non-type template-parameter shall
7419 be a converted constant expression (8.20) of the type of the
7420 template-parameter. */
7423 /* Make sure we return NULL_TREE only if we have really issued
7424 an error, as described above. */
7427 {
7430 }
7433 /* EXPR may have become value-dependent. */
7435 }
7437 {
7442 }
7443 }
7447 else
7450 /* HACK: Due to double coercion, we can get a
7451 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
7452 which is the tree that we built on the first call (see
7453 below when coercing to reference to object or to reference to
7454 function). We just strip everything and get to the arg.
7455 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
7456 for examples. */
7458 {
7459 /* Check this before we strip *& to avoid redundancy. */
7468 {
7469 /* ??? Maybe we could use convert_from_reference here, but we
7470 would need to relax its constraints because the NOP_EXPR
7471 could actually change the type to something more cv-qualified,
7472 and this is not folded by convert_from_reference. */
7477 && (same_type_ignoring_top_level_qualifiers_p
7480 {
7483 }
7484 }
7485 }
7487 /* [temp.arg.nontype]/5, bullet 1
7489 For a non-type template-parameter of integral or enumeration type,
7490 integral promotions (_conv.prom_) and integral conversions
7491 (_conv.integral_) are applied. */
7494 {
7496 {
7501 }
7506 /* Notice that there are constant expressions like '4 % 0' which
7507 do not fold into integer constants. */
7509 {
7511 {
7515 else
7521 /* else cxx_constant_value complained but gave us
7522 a real constant, so go ahead. */
7524 {
7525 /* Some assemble time constant expressions like
7526 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
7527 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
7528 as we can emit them into .rodata initializers of
7529 variables, yet they can't fold into an INTEGER_CST at
7530 compile time. Refuse them here. */
7535 }
7536 }
7537 else
7539 }
7541 /* Avoid typedef problems. */
7544 }
7545 /* [temp.arg.nontype]/5, bullet 2
7547 For a non-type template-parameter of type pointer to object,
7548 qualification conversions (_conv.qual_) and the array-to-pointer
7549 conversion (_conv.array_) are applied. */
7551 {
7554 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
7555 decay_conversion or an explicit cast. If it's a problematic cast,
7556 we'll complain about it below. */
7558 {
7563 {
7566 }
7567 }
7569 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
7571 A template-argument for a non-type, non-template template-parameter
7572 shall be one of: [...]
7574 -- the name of a non-type template-parameter;
7575 -- the address of an object or function with external linkage, [...]
7576 expressed as "& id-expression" where the & is optional if the name
7577 refers to a function or array, or if the corresponding
7578 template-parameter is a reference.
7580 Here, we do not care about functions, as they are invalid anyway
7581 for a parameter of type pointer-to-object. */
7584 /* Non-type template parameters are OK. */
7585 ;
7590 /* Other values, like integer constants, might be valid
7591 non-type arguments of some other type. */
7601 }
7602 /* [temp.arg.nontype]/5, bullet 3
7604 For a non-type template-parameter of type reference to object, no
7605 conversions apply. The type referred to by the reference may be more
7606 cv-qualified than the (otherwise identical) type of the
7607 template-argument. The template-parameter is bound directly to the
7608 template-argument, which must be an lvalue. */
7610 {
7612 expr_type))
7616 {
7621 }
7624 {
7629 }
7631 /* [temp.arg.nontype]/1
7633 A template-argument for a non-type, non-template template-parameter
7634 shall be one of: [...]
7636 -- the address of an object or function with external linkage. */
7639 {
7642 {
7645 "because a reference variable does not have a constant "
7648 }
7649 }
7652 /* OK, dependent reference. We don't want to ask whether a DECL is
7654 else
7655 {
7660 }
7664 }
7665 /* [temp.arg.nontype]/5, bullet 4
7667 For a non-type template-parameter of type pointer to function, only
7668 the function-to-pointer conversion (_conv.func_) is applied. If the
7669 template-argument represents a set of overloaded functions (or a
7670 pointer to such), the matching function is selected from the set
7671 (_over.over_). */
7673 {
7674 /* If the argument is a template-id, we might not have enough
7675 context information to decay the pointer. */
7677 {
7681 }
7684 /* Null pointer values are OK in C++11. */
7690 }
7691 /* [temp.arg.nontype]/5, bullet 5
7693 For a non-type template-parameter of type reference to function, no
7694 conversions apply. If the template-argument represents a set of
7695 overloaded functions, the matching function is selected from the set
7696 (_over.over_). */
7698 {
7700 {
7702 {
7707 }
7709 }
7714 }
7715 /* [temp.arg.nontype]/5, bullet 6
7717 For a non-type template-parameter of type pointer to member function,
7718 no conversions apply. If the template-argument represents a set of
7719 overloaded member functions, the matching member function is selected
7720 from the set (_over.over_). */
7722 {
7727 /* [temp.arg.nontype] bullet 1 says the pointer to member
7728 expression must be a pointer-to-member constant. */
7733 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
7734 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
7737 }
7738 /* [temp.arg.nontype]/5, bullet 7
7740 For a non-type template-parameter of type pointer to data member,
7741 qualification conversions (_conv.qual_) are applied. */
7743 {
7744 /* [temp.arg.nontype] bullet 1 says the pointer to member
7745 expression must be a pointer-to-member constant. */
7753 }
7755 {
7757 {
7762 }
7764 }
7766 {
7767 /* Replace the argument with a reference to the corresponding template
7768 parameter object. */
7773 }
7774 /* A template non-type parameter must be one of the above. */
7775 else
7778 /* Sanity check: did we actually convert the argument to the
7779 right type? */
7783 }
7785 /* Subroutine of coerce_template_template_parms, which returns 1 if
7786 PARM_PARM and ARG_PARM match using the rule for the template
7787 parameters of template template parameters. Both PARM and ARG are
7788 template parameters; the rest of the arguments are the same as for
7789 coerce_template_template_parms.
7790 */
7791 static int
7793 tree arg,
7794 tsubst_flags_t complain,
7795 tree in_decl,
7796 tree outer_args)
7797 {
7806 {
7808 /* We encounter instantiations of templates like
7809 template <template <template <class> class> class TT>
7810 class C; */
7811 {
7815 }
7816 /* Fall through. */
7821 /* Argument is a parameter pack but parameter is not. */
7826 /* The tsubst call is used to handle cases such as
7828 template <int> class C {};
7829 template <class T, template <T> class TT> class D {};
7830 D<int, C> d;
7832 i.e. the parameter list of TT depends on earlier parameters. */
7834 {
7839 }
7843 /* Argument is a parameter pack but parameter is not. */
7850 }
7853 }
7855 /* Coerce template argument list ARGLIST for use with template
7856 template-parameter TEMPL. */
7858 static tree
7860 tsubst_flags_t complain)
7861 {
7862 /* Consider an example where a template template parameter declared as
7864 template <class T, class U = std::allocator<T> > class TT
7866 The template parameter level of T and U are one level larger than
7867 of TT. To proper process the default argument of U, say when an
7868 instantiation `TT<int>' is seen, we need to build the full
7869 arguments containing {int} as the innermost level. Outer levels,
7870 available when not appearing as default template argument, can be
7871 obtained from the arguments of the enclosing template.
7873 Suppose that TT is later substituted with std::vector. The above
7874 instantiation is `TT<int, std::allocator<T> >' with TT at
7875 level 1, and T at level 2, while the template arguments at level 1
7876 becomes {std::vector} and the inner level 2 is {int}. */
7882 {
7883 /* This is an argument of the current template, so we haven't set
7884 DECL_CONTEXT yet. We can also get here when level-lowering a
7885 bound ttp. */
7886 tree relevant_template_parms;
7888 /* Parameter levels that are greater than the level of the given
7889 template template parm are irrelevant. */
7896 }
7903 }
7905 /* A cache of template template parameters with match-all default
7906 arguments. */
7909 /* T is a bound template template-parameter. Copy its arguments into default
7910 arguments of the template template-parameter's template parameters. */
7912 static tree
7914 {
7937 {
7940 {
7943 }
7944 }
7948 tree gen_ntmpl;
7951 else
7961 }
7963 /* ARG is a bound potential template template-argument, and PARGS is a list
7964 of arguments for the corresponding template template-parameter. Adjust
7965 PARGS as appropriate for application to ARG's template, and if ARG is a
7966 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7967 arguments to the template template parameter. */
7969 static tree
7971 {
7975 {
7976 /* When comparing two template template-parameters in partial ordering,
7977 rewrite the one currently being used as an argument to have default
7978 arguments for all parameters. */
7984 }
7985 else
7986 {
7987 tree aparms
7990 }
7993 }
7995 /* Subroutine of unify for the case when PARM is a
7996 BOUND_TEMPLATE_TEMPLATE_PARM. */
7998 static int
8001 {
8005 /* The template template parm might be variadic and the argument
8006 not, so flatten both argument lists. */
8011 {
8012 /* In keeping with P0522R0, adjust P's template arguments
8013 to apply to A's template; then flatten it again. */
8021 /* If the P0522 adjustment eliminated a pack expansion, deduce
8022 empty packs. */
8028 }
8029 else
8030 {
8031 /* Deduce arguments T, i from TT<T> or TT<i>.
8032 We check each element of PARMVEC and ARGVEC individually
8033 rather than the whole TREE_VEC since they can have
8034 different number of elements, which is allowed under N2555. */
8038 /* Check if the parameters end in a pack, making them
8039 variadic. */
8046 /* If the template argument list of P contains a pack
8047 expansion that is not the last template argument, the
8048 entire template argument list is a non-deduced
8049 context. */
8067 DEDUCE_EXACT,
8070 }
8073 }
8075 /* Return 1 if PARM_TMPL and ARG_TMPL match using rule for
8076 template template parameters.
8078 Consider the example:
8079 template <class T> class A;
8080 template<template <class U> class TT> class B;
8082 For B<A>, PARM_TMPL is TT, while ARG_TMPL is A,
8083 and OUTER_ARGS contains A. */
8085 static int
8087 tree arg_tmpl,
8088 tsubst_flags_t complain,
8089 tree in_decl,
8090 tree outer_args)
8091 {
8105 {
8106 /* P0522R0: A template template-parameter P is at least as specialized as
8107 a template template-argument A if, given the following rewrite to two
8108 function templates, the function template corresponding to P is at
8109 least as specialized as the function template corresponding to A
8110 according to the partial ordering rules for function templates
8111 ([temp.func.order]). Given an invented class template X with the
8112 template parameter list of A (including default arguments):
8114 * Each of the two function templates has the same template parameters,
8115 respectively, as P or A.
8117 * Each function template has a single function parameter whose type is
8118 a specialization of X with template arguments corresponding to the
8119 template parameters from the respective function template where, for
8120 each template parameter PP in the template parameter list of the
8121 function template, a corresponding template argument AA is formed. If
8122 PP declares a parameter pack, then AA is the pack expansion
8123 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
8125 If the rewrite produces an invalid type, then P is not at least as
8126 specialized as A. */
8128 /* So coerce P's args to apply to A's parms, and then deduce between A's
8129 args and the converted args. If that succeeds, A is at least as
8130 specialized as P, so they match.*/
8136 /* PARM and ARG might be at different template depths, and we want to
8137 pass the right additional levels of args when coercing PARGS to
8138 ARG_PARMS in case we need to do any substitution into non-type
8139 template parameter types.
8141 OUTER_ARGS are not the right outer levels in this case, as they are
8142 the args we're building up for PARM, and for the coercion we want the
8143 args for ARG. If DECL_CONTEXT isn't set for a template template
8144 parameter, we can assume that it's in the current scope. */
8152 {
8157 /* Only use as many levels from the scope as needed
8158 (excluding the level of ARG). */
8162 else
8165 /* Add the arguments that appear at the levels of ARG. */
8172 }
8173 else
8179 {
8185 }
8186 }
8188 /* Determine whether we have a parameter pack at the end of the
8189 template template parameter's template parameter list. */
8191 {
8198 {
8212 }
8213 }
8219 /* Check all of the template parameters except the parameter pack at
8220 the end (if any). */
8222 {
8231 outer_args))
8234 }
8237 {
8238 /* Check each of the template parameters in the template
8239 argument against the template parameter pack at the end of
8240 the template template parameter. */
8247 {
8254 outer_args))
8256 }
8257 }
8260 }
8262 /* Verifies that the deduced template arguments (in TARGS) for the
8263 template template parameters (in TPARMS) represent valid bindings,
8264 by comparing the template parameter list of each template argument
8265 to the template parameter list of its corresponding template
8266 template parameter, in accordance with DR150. This
8267 routine can only be called after all template arguments have been
8268 deduced. It will return TRUE if all of the template template
8269 parameter bindings are okay, FALSE otherwise. */
8270 bool
8272 {
8276 /* We're dealing with template parms in this process. */
8282 {
8287 {
8292 {
8293 /* Look inside the argument pack. */
8296 }
8299 {
8301 /* Extract the next argument from the argument
8302 pack. */
8306 /* Look at the pattern of the pack expansion. */
8309 /* Extract the template parameters from the template
8310 argument. */
8314 /* Verify that we can coerce the template template
8315 parameters from the template argument to the template
8316 parameter. This requires an exact match. */
8318 && !coerce_template_template_parms
8320 targ,
8321 tf_none,
8322 tparm,
8323 targs))
8324 {
8327 }
8328 }
8329 }
8330 }
8332 out:
8336 }
8338 /* Since type attributes aren't mangled, we need to strip them from
8339 template type arguments. */
8341 tree
8343 {
8353 }
8355 /* And from inside dependent non-type arguments like sizeof(Type). */
8357 static tree
8359 {
8369 }
8371 /* A template declaration can be substituted for a constrained
8372 template template parameter only when the argument is no more
8373 constrained than the parameter. */
8375 static bool
8377 {
8380 /* For now, allow constrained template template arguments
8381 and unconstrained template template parameters. */
8385 /* If the template parameter is constrained, we need to rewrite its
8386 constraints in terms of the ARG's template parameters. This ensures
8387 that all of the template parameter types will have the same depth.
8389 Note that this is only valid when coerce_template_template_parm is
8390 true for the innermost template parameters of PARM and ARG. In other
8391 words, because coercion is successful, this conversion will be valid. */
8394 {
8403 }
8406 }
8408 // Convert a placeholder argument into a binding to the original
8409 // parameter. The original parameter is saved as the TREE_TYPE of
8410 // ARG.
8413 {
8416 }
8418 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
8419 because one of them is dependent. But we need to represent the
8420 conversion for the benefit of cp_tree_equal. */
8422 static tree
8424 {
8425 /* Auto parms get no conversion. */
8428 /* We don't need or want to add this conversion now if we're going to use the
8429 argument for deduction. */
8441 }
8443 /* Convert the indicated template ARG as necessary to match the
8444 indicated template PARM. Returns the converted ARG, or
8445 error_mark_node if the conversion was unsuccessful. Error and
8446 warning messages are issued under control of COMPLAIN. This
8447 conversion is for the Ith parameter in the parameter list. ARGS is
8448 the full set of template arguments deduced so far. */
8450 static tree
8452 tree arg,
8453 tree args,
8454 tsubst_flags_t complain,
8456 tree in_decl)
8457 {
8458 tree orig_arg;
8459 tree val;
8465 /* Trivially convert placeholders. */
8474 {
8475 /* The template argument was the name of some
8476 member function. That's usually
8477 invalid, but static members are OK. In any
8478 case, grab the underlying fields/functions
8479 and issue an error later if required. */
8481 }
8489 /* When determining whether an argument pack expansion is a template,
8490 look at the pattern. */
8494 /* Deal with an injected-class-name used as a template template arg. */
8496 {
8499 {
8509 }
8510 }
8512 is_tmpl_type =
8528 {
8530 {
8534 }
8537 "to refer to a type member of a template parameter, "
8542 typename_type,
8543 complain);
8546 }
8548 {
8550 {
8552 {
8557 {
8558 /* The template argument is a type, but we're expecting
8559 an expression. */
8564 /* [temp.arg]/2: "In a template-argument, an ambiguity
8565 between a type-id and an expression is resolved to a
8566 type-id, regardless of the form of the corresponding
8567 template-parameter." So give the user a clue. */
8570 "for non-type template parameter is treated as "
8572 }
8576 else
8579 }
8580 }
8582 }
8584 {
8586 {
8593 else
8596 }
8598 }
8601 /* We already did the appropriate conversion when packing args. */
8604 {
8606 {
8608 /* The number of argument required is not known yet.
8609 Just accept it for now. */
8611 else
8612 {
8613 /* Strip alias templates that are equivalent to another
8614 template. */
8619 args))
8620 {
8623 /* TEMPLATE_TEMPLATE_PARM node is preferred over
8624 TEMPLATE_DECL. */
8626 {
8631 }
8632 }
8633 else
8634 {
8636 {
8643 }
8646 }
8648 // Check that the constraints are compatible before allowing the
8649 // substitution.
8652 {
8654 {
8660 }
8662 }
8663 }
8664 }
8665 else
8667 /* We only form one instance of each template specialization.
8668 Therefore, if we use a non-canonical variant (i.e., a
8669 typedef), any future messages referring to the type will use
8670 the typedef, which is confusing if those future uses do not
8671 themselves also use the typedef. */
8674 }
8675 else
8676 {
8681 /* We don't have enough levels of args to do any substitution. This
8684 {
8689 }
8690 else
8693 /* Perform array-to-pointer and function-to-pointer conversion
8694 as per [temp.param]/10. */
8700 /* Drop top-level cv-qualifiers on the substituted/deduced type of
8701 this non-type template parameter, as per [temp.param]/6. */
8709 /* We used to call digest_init here. However, digest_init
8710 will report errors, which we don't want when complain
8711 is zero. More importantly, digest_init will try too
8712 hard to convert things: for example, `0' should not be
8713 converted to pointer type at this point according to
8714 the standard. Accepting this is not merely an
8715 extension, since deciding whether or not these
8716 conversions can occur is part of determining which
8717 function template to call, or whether a given explicit
8718 argument specification is valid. */
8720 else
8721 {
8724 }
8735 {
8736 /* Reject template arguments that are references to built-in
8737 functions with no library fallbacks. */
8746 }
8749 {
8750 /* Strip typedefs from the SCOPE_REF. */
8753 complain);
8756 }
8757 }
8760 }
8762 /* Coerces the remaining template arguments in INNER_ARGS (from
8763 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
8764 Returns the coerced argument pack. PARM_IDX is the position of this
8765 parameter in the template parameter list. ARGS is the original
8766 template argument list. */
8767 static tree
8770 tree args,
8771 tree inner_args,
8773 tree new_args,
8775 tree in_decl,
8776 tsubst_flags_t complain)
8777 {
8780 tree packed_args;
8781 tree argument_pack;
8788 {
8789 /* When the template parameter is a non-type template parameter pack
8790 or template template parameter pack whose type or template
8791 parameters use parameter packs, we know exactly how many arguments
8792 we are looking for. Build a vector of the instantiated decls for
8793 these template parameters in PACKED_PARMS. */
8794 /* We can't use make_pack_expansion here because it would interpret a
8795 _DECL as a use rather than a declaration. */
8809 /* If we're doing a partial instantiation of a member template,
8810 verify that all of the types used for the non-type
8811 template parameter pack are, in fact, valid for non-type
8812 template parameters. */
8815 {
8818 {
8823 }
8824 /* We don't know how many args we have yet, just
8825 use the unconverted ones for now. */
8827 }
8830 }
8831 /* Check if we have a placeholder pack, which indicates we're
8832 in the context of a introduction list. In that case we want
8833 to match this pack to the single placeholder. */
8837 {
8840 }
8841 else
8844 /* Convert the remaining arguments, which will be a part of the
8845 parameter pack "parm". */
8848 {
8854 {
8855 /* Once we've packed as many args as we have types, stop. */
8859 /* We don't know how many args we have yet, just
8860 use the unconverted ones for now. */
8862 else
8864 }
8867 {
8870 }
8871 else
8874 in_decl);
8878 }
8882 {
8887 }
8892 else
8893 {
8896 }
8903 }
8905 /* Returns the number of pack expansions in the template argument vector
8906 ARGS. */
8908 static int
8910 {
8915 {
8919 }
8921 }
8923 /* Convert all template arguments to their appropriate types, and
8924 return a vector containing the innermost resulting template
8925 arguments. If any error occurs, return error_mark_node. Error and
8926 warning messages are issued under control of COMPLAIN.
8928 If PARMS represents all template parameters levels, this function
8929 returns a vector of vectors representing all the resulting argument
8930 levels. Note that in this case, only the innermost arguments are
8931 coerced because the outermost ones are supposed to have been coerced
8932 already. Otherwise, if PARMS represents only (the innermost) vector
8933 of parameters, this function returns a vector containing just the
8934 innermost resulting arguments.
8936 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8937 for arguments not specified in ARGS. If REQUIRE_ALL_ARGS is true,
8938 arguments not specified in ARGS must have default arguments which
8939 we'll use to fill in ARGS. */
8941 tree
8943 tree args,
8944 tree in_decl,
8945 tsubst_flags_t complain,
8947 {
8949 tree orig_inner_args;
8950 tree inner_args;
8952 /* When used as a boolean value, indicates whether this is a
8953 variadic template parameter list. Since it's an int, we can also
8954 subtract it from nparms to get the number of non-variadic
8955 parameters. */
8960 /* Adjustment to nparms for fixed parameter packs. */
8965 /* Likewise for parameters with default arguments. */
8973 {
8975 {
8978 }
8980 }
8984 /* Determine if there are any parameter packs or default arguments. */
8986 {
8994 }
8997 /* If there are no parameters that follow a parameter pack, we need to
8998 expand any argument packs so that we can deduce a parameter pack from
8999 some non-packed args followed by an argument pack, as in variadic85.C.
9000 If there are such parameters, we need to leave argument packs intact
9001 so the arguments are assigned properly. This can happen when dealing
9002 with a nested class inside a partial specialization of a class
9003 template, as in variadic92.C, or when deducing a template parameter pack
9004 from a sub-declarator, as in variadic114.C. */
9008 /* Count any pack expansion args. */
9014 && require_all_args
9015 && !variadic_args_p
9018 {
9019 bad_nargs:
9021 {
9023 {
9027 }
9028 else
9035 }
9038 }
9039 /* We can't pass a pack expansion to a non-pack parameter of an alias
9040 template (DR 1430). */
9044 && variadic_args_p
9046 {
9048 {
9050 {
9056 {
9059 "pack expansion argument for non-pack parameter "
9061 else
9063 "pack expansion argument for non-pack parameter "
9067 }
9068 }
9070 found:;
9071 }
9073 }
9075 /* We need to evaluate the template arguments, even though this
9076 template-id may be nested within a "sizeof". */
9077 cp_evaluated ev;
9083 {
9084 tree arg;
9085 tree parm;
9087 /* Get the Ith template parameter. */
9091 {
9094 }
9096 /* Calculate the next argument. */
9099 else
9105 {
9106 /* Some arguments will be placed in the
9107 template parameter pack PARM. */
9114 {
9115 /* We don't know how many args we have yet, just use the
9116 unconverted (and still packed) ones for now. */
9120 }
9124 /* Store this argument. */
9126 {
9127 lost++;
9128 /* We are done with all of the arguments. */
9131 }
9132 else
9133 {
9137 {
9140 }
9141 }
9144 }
9146 {
9148 {
9149 /* "If every valid specialization of a variadic template
9150 requires an empty template parameter pack, the template is
9151 ill-formed, no diagnostic required." So check that the
9152 pattern works with this parameter. */
9157 in_decl);
9159 {
9164 }
9166 /* Recover from missing typename. */
9170 /* We don't know how many args we have yet, just
9171 use the unconverted ones for now. */
9175 }
9176 }
9178 {
9179 /* There must be a default arg in this case. */
9182 /* The position of the first default template argument,
9183 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
9184 Record that. */
9188 }
9189 else
9193 {
9196 }
9198 {
9199 /* This can occur if there was an error in the template
9200 parameter list itself (which we would already have
9201 reported) that we are trying to recover from, e.g., a class
9202 template with a parameter list such as
9203 template<typename..., typename> (cpp0x/variadic150.C). */
9206 /* This can also happen with a fixed parameter pack (71834). */
9209 }
9210 else
9216 lost++;
9219 }
9222 {
9223 /* If we had fixed parameter packs, we didn't know how many arguments we
9224 actually needed earlier; now we do. */
9228 }
9231 {
9232 /* We had some pack expansion arguments that will only work if the packs
9233 are empty, but wait until instantiation time to complain.
9234 See variadic-ttp3.C. */
9236 /* Except that we can't provide empty packs to alias templates or
9237 concepts when there are no corresponding parameters. Basically,
9238 we can get here with this:
9240 template<typename T> concept C = true;
9242 template<typename... Args>
9243 requires C<Args...>
9244 void f();
9246 When parsing C<Args...>, we try to form a concept check of
9247 C<?, Args...>. Without the extra check for substituting an empty
9248 pack past the last parameter, we can accept the check as valid.
9250 FIXME: This may be valid for alias templates (but I doubt it).
9252 FIXME: The error could be better also. */
9254 {
9259 }
9270 }
9273 {
9276 }
9283 }
9285 /* Returns true if T is a wrapper to make a C++20 template parameter
9286 object const. */
9288 static bool
9290 {
9296 }
9298 /* Returns 1 if template args OT and NT are equivalent. */
9300 int
9302 {
9315 /* DR 1558: Don't treat an alias template specialization with dependent
9316 arguments as equivalent to its underlying type when used as a template
9317 argument; we need them to be distinct so that we substitute into the
9318 specialization arguments at instantiation time. And aliases can't be
9319 equivalent without being ==, so we don't need to look any deeper.
9321 During partial ordering, however, we need to treat them normally so we can
9322 order uses of the same alias with different cv-qualification (79960). */
9328 /* For member templates */
9341 {
9345 }
9346 else
9347 {
9348 /* Try to treat a template non-type argument that has been converted
9349 to the parameter type as equivalent to one that hasn't yet. */
9363 }
9364 }
9366 /* Returns true iff the OLDARGS and NEWARGS are in fact identical sets of
9367 template arguments. Returns false otherwise, and updates OLDARG_PTR and
9368 NEWARG_PTR with the offending arguments if they are non-NULL. */
9370 bool
9374 {
9385 {
9390 {
9396 }
9397 }
9399 }
9403 {
9405 }
9407 /* Implement a freelist interface for objects of type T.
9409 Head is a separate object, rather than a regular member, so that we
9410 can define it as a GTY deletable pointer, which is highly
9411 desirable. A data member could be declared that way, but then the
9412 containing object would implicitly get GTY((user)), which would
9413 prevent us from instantiating freelists as global objects.
9414 Although this way we can create freelist global objects, they're
9415 such thin wrappers that instantiating temporaries at every use
9416 loses nothing and saves permanent storage for the freelist object.
9418 Member functions next, anew, poison and reinit have default
9419 implementations that work for most of the types we're interested
9420 in, but if they don't work for some type, they should be explicitly
9421 specialized. See the comments before them for requirements, and
9422 the example specializations for the tree_list_freelist. */
9424 class freelist
9425 {
9426 /* Return the next object in a chain. We could just do type
9427 punning, but if we access the object with its underlying type, we
9428 avoid strict-aliasing trouble. This needs only work between
9429 poison and reinit. */
9432 /* Return a newly allocated, uninitialized or minimally-initialized
9433 object of type T. Any initialization performed by anew should
9434 either remain across the life of the object and the execution of
9435 poison, or be redone by reinit. */
9438 /* Optionally scribble all over the bits holding the object, so that
9439 they become (mostly?) uninitialized memory. This is called while
9440 preparing to make the object part of the free list. */
9445 #ifdef ENABLE_GC_CHECKING
9446 /* Poison the data, to indicate the data is garbage. */
9449 #endif
9450 /* Let valgrind know the object is free. */
9453 /* Let valgrind know the next portion of the object is available,
9454 but uninitialized. */
9456 }
9458 /* Bring an object that underwent at least one lifecycle after anew
9459 and before the most recent free and poison, back to a usable
9460 state, reinitializing whatever is needed for it to be
9461 functionally equivalent to an object just allocated and returned
9462 by anew. This may poison or clear the next field, used by
9463 freelist housekeeping after poison was called. */
9467 #ifdef ENABLE_GC_CHECKING
9469 #endif
9470 /* Let valgrind know the entire object is available, but
9471 uninitialized. */
9473 }
9475 /* Reference a GTY-deletable pointer that points to the first object
9476 in the free list proper. */
9479 /* Construct a freelist object chaining objects off of HEAD. */
9482 /* Add OBJ to the free object list. The former head becomes OBJ's
9483 successor. */
9485 {
9489 }
9491 /* Take an object from the free list, if one is available, or
9492 allocate a new one. Objects taken from the free list should be
9493 regarded as filled with garbage, except for bits that are
9494 configured to be preserved across free and alloc. */
9496 {
9498 {
9503 }
9504 else
9506 }
9507 };
9509 /* Explicitly specialize the interfaces for freelist<tree_node>: we
9510 want to allocate a TREE_LIST using the usual interface, and ensure
9511 TREE_CHAIN remains functional. Alas, we have to duplicate a bit of
9512 build_tree_list logic in reinit, so this could go out of sync. */
9516 {
9518 }
9520 inline tree
9522 {
9524 }
9528 {
9534 #ifdef ENABLE_GC_CHECKING
9537 /* Poison the data, to indicate the data is garbage. */
9540 #endif
9541 /* Let valgrind know the object is free. */
9543 /* But we still want to use the TREE_CODE and TREE_CHAIN parts. */
9547 #ifdef ENABLE_GC_CHECKING
9549 /* Keep TREE_CHAIN functional. */
9551 #else
9553 #endif
9554 }
9558 {
9561 #ifdef ENABLE_GC_CHECKING
9565 #endif
9567 /* Let valgrind know the entire object is available, but
9568 uninitialized. */
9571 #ifdef ENABLE_GC_CHECKING
9573 #else
9575 #endif
9576 }
9578 /* Point to the first object in the TREE_LIST freelist. */
9580 /* Return the/an actual TREE_LIST freelist. */
9583 {
9585 }
9587 /* Point to the first object in the tinst_level freelist. */
9589 /* Return the/an actual tinst_level freelist. */
9592 {
9594 }
9596 /* Point to the first object in the pending_template freelist. */
9598 /* Return the/an actual pending_template freelist. */
9601 {
9603 }
9605 /* Build the TREE_LIST object out of a split list, store it
9606 permanently, and return it. */
9607 tree
9609 {
9618 }
9622 /* Increment OBJ's refcount unless it is already infinite. */
9625 {
9629 }
9631 /* Release storage for OBJ and node, if it's a TREE_LIST. */
9632 void
9634 {
9638 }
9640 /* Decrement OBJ's refcount if not infinite. If it reaches zero, release
9641 OBJ's DECL and OBJ, and start over with the tinst_level object that
9642 used to be referenced by OBJ's NEXT. */
9643 static void
9645 {
9649 {
9653 }
9654 }
9656 /* Modify PTR so that it points to OBJ, adjusting the refcounts of OBJ
9657 and of the former PTR. Omitting the second argument is equivalent
9658 to passing (T*)NULL; this is allowed because passing the
9659 zero-valued integral constant NULL confuses type deduction and/or
9660 overload resolution. */
9662 static void
9664 {
9668 }
9670 static void
9672 {
9682 /* We are called both from instantiate_decl, where we've already had a
9683 tinst_level pushed, and instantiate_template, where we haven't.
9684 Compensate. */
9686 level = !current_tinst_level
9698 else
9707 }
9710 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
9711 ARGLIST. Valid choices for FNS are given in the cp-tree.def
9712 documentation for TEMPLATE_ID_EXPR. */
9714 tree
9716 {
9723 {
9726 }
9729 {
9732 unknown_type_node,
9734 arglist);
9736 }
9739 }
9741 /* Within the scope of a template class S<T>, the name S gets bound
9742 (in build_self_reference) to a TYPE_DECL for the class, not a
9743 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
9744 or one of its enclosing classes, and that type is a template,
9745 return the associated TEMPLATE_DECL. Otherwise, the original
9746 DECL is returned.
9748 Also handle the case when DECL is a TREE_LIST of ambiguous
9749 injected-class-names from different bases. */
9751 tree
9753 {
9757 /* DR 176: A lookup that finds an injected-class-name (10.2
9758 [class.member.lookup]) can result in an ambiguity in certain cases
9759 (for example, if it is found in more than one base class). If all of
9760 the injected-class-names that are found refer to specializations of
9761 the same class template, and if the name is followed by a
9762 template-argument-list, the reference refers to the class template
9763 itself and not a specialization thereof, and is not ambiguous. */
9765 {
9768 {
9774 }
9777 else
9779 }
9785 }
9787 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
9788 parameters, find the desired type.
9790 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
9792 IN_DECL, if non-NULL, is the template declaration we are trying to
9793 instantiate.
9795 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
9796 the class we are looking up.
9798 Issue error and warning messages under control of COMPLAIN.
9800 If the template class is really a local class in a template
9801 function, then the FUNCTION_CONTEXT is the function in which it is
9802 being instantiated.
9804 ??? Note that this function is currently called *twice* for each
9805 template-id: the first time from the parser, while creating the
9806 incomplete type (finish_template_type), and the second type during the
9807 real instantiation (instantiate_template_class). This is surely something
9808 that we want to avoid. It also causes some problems with argument
9809 coercion (see convert_nontype_argument for more information on this). */
9811 tree
9814 {
9818 tree t;
9821 spec_entry elt;
9822 hashval_t hash;
9825 {
9829 else
9830 {
9837 }
9838 }
9840 {
9843 /* If we are declaring a constructor, say A<T>::A<T>, we will get
9844 an implicit typename for the second A. Deal with it. */
9849 {
9852 }
9853 }
9856 {
9859 }
9861 {
9864 }
9866 {
9869 }
9871 /* Issue an error message if we didn't find a template. */
9873 {
9877 }
9880 /* Make sure it's a user visible template, if it was named by
9881 the user. */
9884 {
9886 {
9890 }
9892 }
9896 /* An alias that just changes the name of a template is equivalent to the
9897 other template, so if any of the arguments are pack expansions, strip
9898 the alias to avoid problems with a pack expansion passed to a non-pack
9899 alias template parameter (DR 1430). */
9904 {
9905 tree parm;
9914 }
9915 else
9916 {
9918 tree gen_tmpl;
9919 tree type_decl;
9927 /* An error occurred while building the template TEMPL, and a
9928 diagnostic has most certainly been emitted for that
9929 already. Let's propagate that error. */
9941 {
9942 /* We've been given an incomplete set of template arguments.
9943 For example, given:
9945 template <class T> struct S1 {
9946 template <class U> struct S2 {};
9947 template <class U> struct S2<U*> {};
9948 };
9950 we will be called with an ARGLIST of `U*', but the
9951 TEMPLATE will be `template <class T> template
9952 <class U> struct S1<T>::S2'. We must fill in the missing
9953 arguments. */
9957 }
9959 /* Now we should have enough arguments. */
9962 /* From here on, we're only interested in the most general
9963 template. */
9965 /* Shortcut looking up the current class scope again. */
9969 {
9980 }
9982 /* Calculate the BOUND_ARGS. These will be the args that are
9983 actually tsubst'd into the definition to create the
9984 instantiation. */
9989 /* We were unable to bind the arguments. */
9992 /* In the scope of a template class, explicit references to the
9993 template class refer to the type of the template, not any
9994 instantiation of it. For example, in:
9996 template <class T> class C { void f(C<T>); }
9998 the `C<T>' is just the same as `C'. Outside of the
9999 class, however, such a reference is an instantiation. */
10003 {
10008 }
10010 /* If we already have this specialization, return it. */
10020 /* If the template's constraints are not satisfied,
10021 then we cannot form a valid type.
10023 Note that the check is deferred until after the hash
10024 lookup. This prevents redundant checks on previously
10025 instantiated specializations. */
10029 {
10031 {
10032 auto_diagnostic_group d;
10035 }
10037 }
10041 /* If the deduced arguments are invalid, then the binding
10042 failed. */
10046 complain))
10053 /* This occurs when the user has tried to define a tagged type
10054 in a scope that forbids it. We emitted an error during the
10055 parse. We didn't complete the bail out then, so here we
10056 are. */
10061 {
10063 /* If the context of the partially instantiated template is
10064 already non-dependent, then we might as well use it. */
10066 else
10067 {
10070 /* Try completing the enclosing context if it's not already so. */
10073 {
10076 {
10077 /* Completion could have caused us to register the desired
10078 specialization already, so check the table again. */
10082 }
10083 }
10084 }
10085 }
10086 else
10095 /* Create the type. */
10097 {
10098 /* The user referred to a specialization of an alias
10099 template represented by GEN_TMPL.
10101 [temp.alias]/2 says:
10103 When a template-id refers to the specialization of an
10104 alias template, it is equivalent to the associated
10105 type obtained by substitution of its
10106 template-arguments for the template-parameters in the
10107 type-id of the alias template. */
10110 /* Note that the call above (by indirectly calling
10111 register_specialization in tsubst_decl) registers the
10112 TYPE_DECL representing the specialization of the alias
10113 template. So next time someone substitutes ARGLIST for
10114 the template parms into the alias template (GEN_TMPL),
10115 she'll get that TYPE_DECL back. */
10119 }
10121 {
10123 {
10134 }
10135 else
10136 {
10137 /* We don't want to call start_enum for this type, since
10138 the values for the enumeration constants may involve
10139 template parameters. And, no one should be interested
10140 in the enumeration constants for such a type. */
10143 }
10147 }
10149 {
10150 /* Lambda closures are regenerated in tsubst_lambda_expr, not
10151 instantiated here. */
10159 /* A local class. Make sure the decl gets registered properly. */
10166 /* This instantiation is another name for the primary
10167 template type. Set the TYPE_CANONICAL field
10168 appropriately. */
10172 }
10173 else
10176 /* If we called start_enum or pushtag above, this information
10177 will already be set up. */
10180 {
10187 }
10190 /* Although GEN_TMPL is the TEMPLATE_DECL, it has the same value
10191 of export flag. We want to propagate this because it might
10192 be a friend declaration that pushes a new hidden binding. */
10196 {
10202 {
10205 }
10206 }
10210 {
10214 {
10215 tree attributes
10223 }
10224 }
10226 /* Let's consider the explicit specialization of a member
10227 of a class template specialization that is implicitly instantiated,
10228 e.g.:
10229 template<class T>
10230 struct S
10231 {
10232 template<class U> struct M {}; //#0
10233 };
10235 template<>
10236 template<>
10237 struct S<int>::M<char> //#1
10238 {
10239 int i;
10240 };
10241 [temp.expl.spec]/4 says this is valid.
10243 In this case, when we write:
10244 S<int>::M<char> m;
10246 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
10247 the one of #0.
10249 When we encounter #1, we want to store the partial instantiation
10250 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
10252 For all cases other than this "explicit specialization of member of a
10253 class template", we just want to store the most general template into
10254 the CLASSTYPE_TI_TEMPLATE of M.
10256 This case of "explicit specialization of member of a class template"
10257 only happens when:
10258 1/ the enclosing class is an instantiation of, and therefore not
10259 the same as, the context of the most general template, and
10260 2/ we aren't looking at the partial instantiation itself, i.e.
10261 the innermost arguments are not the same as the innermost parms of
10262 the most general template.
10264 So it's only when 1/ and 2/ happens that we want to use the partial
10265 instantiation of the member template in lieu of its most general
10266 template. */
10270 /* the enclosing class must be an instantiation... */
10273 {
10277 tree partial_inst_args =
10284 use_partial_inst_tmpl =
10285 /*...and we must not be looking at the partial instantiation
10286 itself. */
10288 partial_inst_args);
10289 }
10292 /* This case is easy; there are no member templates involved. */
10294 else
10295 {
10296 /* This is a full instantiation of a member template. Find
10297 the partial instantiation of which this is an instance. */
10299 /* Temporarily reduce by one the number of levels in the ARGLIST
10300 so as to avoid comparing the last set of arguments. */
10302 /* We don't use COMPLAIN in the following call because this isn't
10303 the immediate context of deduction. For instance, tf_partial
10304 could be set here as we might be at the beginning of template
10305 argument deduction when any explicitly specified template
10306 arguments are substituted into the function type. tf_partial
10307 could lead into trouble because we wouldn't find the partial
10308 instantiation that might have been created outside tf_partial
10309 context, because the levels of template parameters wouldn't
10310 match, because in a tf_partial context, tsubst doesn't reduce
10311 TEMPLATE_PARM_LEVEL. */
10314 /* FOUND is either a proper class type, or an alias
10315 template specialization. In the later case, it's a
10316 TYPE_DECL, resulting from the substituting of arguments
10317 for parameters in the TYPE_DECL of the alias template
10318 done earlier. So be careful while getting the template
10319 of FOUND. */
10321 ? found
10328 {
10329 /* If this partial instantiation is specialized, we want to
10330 use it for hash table lookup. */
10334 }
10335 }
10337 /* Build template info for the new specialization. */
10347 /* Note this use of the partial instantiation so we can check it
10348 later in maybe_process_partial_specialization. */
10356 /* Now that the type has been registered on the instantiations
10357 list, we set up the enumerators. Because the enumeration
10358 constants may involve the enumeration type itself, we make
10359 sure to register the type first, and then create the
10360 constants. That way, doing tsubst_expr for the enumeration
10361 constants won't result in recursive calls here; we'll find
10362 the instantiation and exit above. */
10366 /* If the type makes use of template parameters, the
10367 code that generates debugging information will crash. */
10370 /* Possibly limit visibility based on template args. */
10377 }
10378 }
10380 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
10382 tree
10384 {
10395 /* The type of the expression is NULL_TREE since the template-id could refer
10396 to an explicit or partial specialization. */
10398 }
10400 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR if it's
10401 not dependent. */
10403 tree
10405 {
10409 /* If the template or arguments are dependent, then we
10410 can't resolve the TEMPLATE_ID_EXPR yet. */
10416 {
10418 {
10419 auto_diagnostic_group d;
10422 }
10424 }
10427 }
10429 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
10430 TARGS template args, and instantiate it if it's not dependent. */
10432 tree
10434 tsubst_flags_t complain)
10435 {
10442 }
10444 /* If the set of template parameters PARMS contains a template parameter
10445 at the given LEVEL and INDEX, then return this parameter. Otherwise
10446 return NULL_TREE. */
10448 static tree
10450 {
10459 }
10461 /* Return the TREE_LIST for the template parameter from PARMS that positionally
10462 corresponds to the template parameter PARM, or else return NULL_TREE. */
10464 static tree
10466 {
10470 }
10472 /* As above, but pull out the actual parameter. */
10474 static tree
10476 {
10482 /* As in template_parm_to_arg. */
10485 else
10490 }
10491 \f
10492 struct pair_fn_data
10493 {
10494 tree_fn_t fn;
10495 tree_fn_t any_fn;
10497 /* True when we should also visit template parameters that occur in
10498 non-deduced contexts. */
10501 };
10503 /* Called from for_each_template_parm via walk_tree. */
10505 static tree
10507 {
10514 #define WALK_SUBTREE(NODE) \
10515 do \
10516 { \
10517 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
10518 pfd->include_nondeduced_p, \
10519 pfd->any_fn); \
10520 if (result) goto out; \
10521 } \
10522 while (0)
10532 {
10536 /* Fall through. */
10542 else
10552 /* Since we're not going to walk subtrees, we have to do this
10553 explicitly here. */
10555 /* Fall through. */
10558 /* Check the return type. */
10561 /* Check the parameter types. Since default arguments are not
10562 instantiated until they are needed, the TYPE_ARG_TYPES may
10563 contain expressions that involve template parameters. But,
10564 no-one should be looking at them yet. And, once they're
10565 instantiated, they don't contain template parameters, so
10566 there's no point in looking at them then, either. */
10567 {
10568 tree parm;
10573 /* Since we've already handled the TYPE_ARG_TYPES, we don't
10574 want walk_tree walking into them itself. */
10576 }
10579 {
10583 }
10599 {
10602 }
10625 /* Record template parameters such as `T' inside `TT<T>'. */
10627 /* Fall through. */
10639 /* A template template parameter is encountered. */
10643 /* Already substituted template template parameter */
10648 /* A template-id in a TYPENAME_TYPE might be a deduced context after
10649 partial instantiation. */
10656 /* If there's no type, then this thing must be some expression
10657 involving template parameters. */
10667 /* These are non-deduced contexts. */
10689 }
10691 #undef WALK_SUBTREE
10693 /* We didn't find any template parameters we liked. */
10694 out:
10696 }
10698 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
10699 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
10700 call FN with the parameter and the DATA.
10701 If FN returns nonzero, the iteration is terminated, and
10702 for_each_template_parm returns 1. Otherwise, the iteration
10703 continues. If FN never returns a nonzero value, the value
10704 returned by for_each_template_parm is 0. If FN is NULL, it is
10705 considered to be the function which always returns 1.
10707 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
10708 parameters that occur in non-deduced contexts. When false, only
10709 visits those template parameters that can be deduced. */
10711 static tree
10715 tree_fn_t any_fn)
10716 {
10718 tree result;
10720 /* Set up. */
10726 /* Walk the tree. (Conceptually, we would like to walk without
10727 duplicates, but for_each_template_parm_r recursively calls
10728 for_each_template_parm, so we would need to reorganize a fair
10729 bit to use walk_tree_without_duplicates, so we keep our own
10730 visited list.) */
10733 else
10736 for_each_template_parm_r,
10740 /* Clean up. */
10742 {
10745 }
10748 }
10750 struct find_template_parameter_info
10751 {
10755 {}
10761 tree ctx_parms;
10768 };
10770 /* Appends the declaration of T to the list in DATA. */
10772 static int
10774 {
10777 /* Template parameters declared within the expression are not part of
10778 the parameter mapping. For example, in this concept:
10780 template<typename T>
10781 concept C = requires { <expr> } -> same_as<int>;
10783 the return specifier same_as<int> declares a new decltype parameter
10784 that must not be part of the parameter mapping. The same is true
10785 for generic lambda parameters, lambda template parameters, etc. */
10793 /* We want the underlying TEMPLATE_TEMPLATE_PARM, not the
10794 BOUND_TEMPLATE_TEMPLATE_PARM itself. */
10797 /* This template parameter might be an argument to a cached dependent
10798 specalization that was formed earlier inside some other template, in
10799 which case the parameter is not among the ones that are in-scope.
10800 Look in CTX_PARMS to find the corresponding in-scope template
10801 parameter, and use it instead. */
10805 /* Arguments like const T yield parameters like const T. This means that
10806 a template-id like X<T, const T> would yield two distinct parameters:
10807 T and const T. Adjust types to their unqualified versions. */
10811 {
10812 /* Append T to PARM_LIST. */
10816 }
10818 /* Verify the parameter we found has a valid index. */
10820 {
10826 }
10829 }
10831 /* Ensure that we recursively examine certain terms that are not normally
10832 visited in for_each_template_parm_r. */
10834 static int
10836 {
10839 #define WALK_SUBTREE(NODE) \
10840 do \
10841 { \
10842 for_each_template_parm (NODE, keep_template_parm, data, \
10843 &ftpi->visited, true, \
10844 any_template_parm_r); \
10845 } \
10846 while (0)
10848 /* A mention of a member alias/typedef is a use of all of its template
10849 arguments, including those from the enclosing class, so we don't use
10850 alias_template_specialization_p here. */
10856 {
10858 /* Type constraints of a placeholder type may contain parameters. */
10865 /* Search through references to variable templates. */
10875 /* If T is a member template that shares template parameters with
10876 ctx_parms, we need to mark all those parameters for mapping.
10877 To that end, it should suffice to just walk the DECL_CONTEXT of
10878 the template (assuming the template is not overly general). */
10883 {
10884 /* Look in the parms and body. */
10888 }
10893 /* The conversion-type-id of a conversion operator may be dependent. */
10904 }
10906 /* Keep walking. */
10908 }
10910 /* Look through T for template parameters. */
10912 tree
10914 {
10917 any_template_parm_r);
10918 }
10920 /* As above, but also recursively look into the default arguments of template
10921 parameters we found. Used for alias CTAD. */
10923 tree
10925 {
10928 /* Since newly found parms are added to the end of the list, we
10929 can just walk it until we reach the end. */
10931 {
10936 }
10938 }
10940 /* True if PARM was found by a previous call to find_in. PARM can be a
10941 TREE_LIST, a DECL_TEMPLATE_PARM_P, or a TEMPLATE_PARM_P. */
10943 bool
10945 {
10950 else
10954 }
10956 /* Returns a list of unique template parameters found within T, where CTX_PARMS
10957 are the template parameters in scope. */
10959 tree
10961 {
10968 }
10970 /* Returns true if T depends on any template parameter. */
10972 bool
10974 {
10978 /* Namespaces can't depend on any template parameters. */
10994 else
10996 }
10998 /* Returns true if T depends on any template parameter with level LEVEL. */
11000 bool
11002 {
11005 }
11007 /* Returns true if the signature of DECL depends on any template parameter from
11008 its enclosing class. */
11010 static bool
11012 {
11016 else
11025 {
11028 {
11033 template_parm_outer_level,
11043 }
11044 }
11048 }
11050 /* Returns true if the constraints of DECL depend on any template parameters
11051 from its enclosing scope. */
11053 bool
11055 {
11062 {
11065 else
11067 }
11073 }
11075 /* Returns TRUE iff INST is an instantiation we don't need to do in an
11076 ill-formed translation unit, i.e. a variable or function that isn't
11077 usable in a constant expression. */
11081 {
11087 }
11089 /* Returns TRUE iff we should refuse to instantiate DECL because it's
11090 neglectable and instantiated from within an erroneous instantiation. */
11092 static bool
11094 {
11100 /* Avoid instantiating members of an ill-formed class. */
11101 bool refuse
11106 {
11111 }
11114 {
11115 /* Don't warn about it not being defined. */
11117 tree clone;
11120 }
11122 }
11130 /* We're starting to instantiate D; record the template instantiation context
11131 at LOC for diagnostics and to restore it later. */
11133 bool
11135 {
11139 {
11140 /* Tell error.cc not to try to instantiate any templates. */
11143 "template instantiation depth exceeds maximum of %d"
11145 max_tinst_depth);
11147 }
11149 /* If the current instantiation caused problems, don't let it instantiate
11150 anything else. Do allow deduction substitution and decls usable in
11151 constant expressions. */
11153 {
11154 /* Avoid no_linkage_errors and unused function (and all other)
11155 warnings for this decl. */
11158 }
11160 /* When not -quiet, dump template instantiations other than functions, since
11161 announce_function will take care of those. */
11183 }
11185 /* We're starting substitution of TMPL<ARGS>; record the template
11186 substitution context for diagnostics and to restore it later. */
11188 bool
11190 {
11192 }
11194 /* We're starting to instantiate D; record INPUT_LOCATION and the
11195 template instantiation context for diagnostics and to restore it
11196 later. */
11198 bool
11200 {
11202 }
11204 /* Likewise, but record LOC as the program location. */
11206 bool
11208 {
11211 }
11213 /* We're done instantiating this template; return to the instantiation
11214 context. */
11216 void
11218 {
11219 /* Restore the filename and line number stashed away when we started
11220 this instantiation. */
11224 }
11226 /* We're instantiating a deferred template; restore the template
11227 instantiation context in which the instantiation was requested, which
11228 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
11230 static tree
11232 {
11244 }
11246 /* Returns the TINST_LEVEL which gives the original instantiation
11247 context. */
11251 {
11257 }
11259 /* True iff T is a friend function declaration that is not itself a template
11260 and is not defined in a class template. */
11262 bool
11264 {
11267 {
11271 /* DECL_FRIEND_CONTEXT is set for a friend defined in class. */
11274 /* Non-templated friends in a class template are still represented with a
11275 TEMPLATE_DECL; check that its primary template is the befriending
11276 class. Note that DECL_PRIMARY_TEMPLATE is null for
11277 template <class T> friend A<T>::f(); */
11281 }
11282 else
11284 }
11286 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
11287 vector of template arguments, as for tsubst.
11289 Returns an appropriate tsubst'd friend declaration. */
11291 static tree
11293 {
11294 tree new_friend;
11299 /* This was a friend declared with an explicit template
11300 argument list, e.g.:
11302 friend void f<>(T);
11304 to indicate that f was a template instantiation, not a new
11305 function declaration. Now, we have to figure out what
11306 instantiation of what template. */
11307 {
11309 tree new_args;
11310 tree tmpl;
11313 /* Friend functions are looked up in the containing namespace scope.
11314 We must enter that scope, to avoid finding member functions of the
11315 current class with same name. */
11329 tsk_none);
11331 }
11337 /* The NEW_FRIEND will look like an instantiation, to the
11338 compiler, but is not an instantiation from the point of view of
11339 the language. For example, we might have had:
11341 template <class T> struct S {
11342 template <class U> friend void f(T, U);
11343 };
11345 Then, in S<int>, template <class U> void f(int, U) is not an
11346 instantiation of anything. */
11350 {
11356 /* Substitute TEMPLATE_PARMS_CONSTRAINTS so that parameter levels will
11357 match in decls_match. */
11362 {
11364 /* As well as each TEMPLATE_PARM_CONSTRAINTS. */
11366 tf_warning_or_error);
11367 }
11368 }
11370 /* The mangled name for the NEW_FRIEND is incorrect. The function
11371 is not a template instantiation and should not be mangled like
11372 one. Therefore, we forget the mangling here; we'll recompute it
11373 later if we need it. */
11375 {
11378 }
11381 {
11382 tree old_decl;
11383 tree ns;
11385 /* We must save some information from NEW_FRIEND before calling
11386 duplicate decls since that function will free NEW_FRIEND if
11387 possible. */
11391 (new_friend_template_info
11398 {
11399 /* This declaration is a `primary' template. */
11404 }
11406 /* Inside pushdecl_namespace_level, we will push into the
11407 current namespace. However, the friend function should go
11408 into the namespace of the template. */
11418 {
11419 /* This new friend declaration matched an existing
11420 declaration. For example, given:
11422 template <class T> void f(T);
11423 template <class U> class C {
11424 template <class T> friend void f(T) {}
11425 };
11427 the friend declaration actually provides the definition
11428 of `f', once C has been instantiated for some type. So,
11429 old_decl will be the out-of-class template declaration,
11430 while new_friend is the in-class definition.
11432 But, if `f' was called before this point, the
11433 instantiation of `f' will have DECL_TI_ARGS corresponding
11434 to `T' but not to `U', references to which might appear
11435 in the definition of `f'. Previously, the most general
11436 template for an instantiation of `f' was the out-of-class
11437 version; now it is the in-class version. Therefore, we
11438 run through all specialization of `f', adding to their
11439 DECL_TI_ARGS appropriately. In particular, they need a
11440 new set of outer arguments, corresponding to the
11441 arguments for this class instantiation.
11443 The same situation can arise with something like this:
11445 friend void f(int);
11446 template <class T> class C {
11447 friend void f(T) {}
11448 };
11450 when `C<int>' is instantiated. Now, `f(int)' is defined
11451 in the class. */
11454 /* On the other hand, if the in-class declaration does
11455 *not* provide a definition, then we don't want to alter
11456 existing definitions. We can just leave everything
11457 alone. */
11458 ;
11459 else
11460 {
11464 /* Overwrite whatever template info was there before, if
11465 any, with the new template information pertaining to
11466 the declaration. */
11470 {
11471 /* We should have called reregister_specialization in
11472 duplicate_decls. */
11477 /* Instantiate it if the global has already been used. */
11481 }
11482 else
11483 {
11484 tree t;
11486 /* Indicate that the old function template is a partial
11487 instantiation. */
11495 /* Reassign any specializations already in the hash table
11496 to the new more general template, and add the
11497 additional template args. */
11501 {
11503 spec_entry elt;
11515 register_specialization
11518 }
11520 }
11521 }
11523 /* The information from NEW_FRIEND has been merged into OLD_DECL
11524 by duplicate_decls. */
11526 }
11528 /* We've just introduced a namespace-scope function in the purview
11529 without necessarily having opened the enclosing namespace, so
11530 make sure the namespace is in the purview now too. */
11535 }
11536 else
11537 {
11541 /* In the code
11542 template <class T> class C {
11543 template <class U> friend void C1<U>::f (); // case 1
11544 friend void C2<T>::f (); // case 2
11545 };
11546 we only need to make sure CONTEXT is a complete type for
11547 case 2. To distinguish between the two cases, we note that
11548 CONTEXT of case 1 remains dependent type after tsubst while
11549 this isn't true for case 2. */
11559 {
11561 /* do_friend adds the TEMPLATE_DECL for any member friend
11562 template even if it isn't a member template, i.e.
11563 template <class T> friend A<T>::f();
11564 Look through it in that case. */
11568 /* Check to see that the declaration is really present, and,
11569 possibly obtain an improved declaration. */
11574 }
11575 }
11578 }
11580 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
11581 template arguments, as for tsubst.
11583 Returns an appropriate tsubst'd friend type or error_mark_node on
11584 failure. */
11586 static tree
11588 {
11589 tree tmpl;
11592 {
11595 }
11600 else
11601 {
11604 }
11610 {
11611 /* The friend template has already been declared. Just
11612 check to see that the declarations match, and install any new
11613 default parameters. We must tsubst the default parameters,
11614 of course. We only need the innermost template parameters
11615 because that is all that redeclare_class_template will look
11616 at. */
11619 {
11623 tf_warning_or_error);
11633 }
11634 }
11635 else
11636 {
11637 /* The friend template has not already been declared. In this
11638 case, the instantiation of the template class will cause the
11639 injection of this template into the namespace scope. */
11643 {
11644 /* The new TMPL is not an instantiation of anything, so we
11645 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
11646 for the new type because that is supposed to be the
11647 corresponding template decl, i.e., TMPL. */
11654 /* Substitute into and set the constraints on the new declaration. */
11656 {
11664 }
11666 /* Inject this template into the enclosing namspace scope. */
11668 }
11669 }
11673 else
11677 }
11679 /* Returns zero if TYPE cannot be completed later due to circularity.
11680 Otherwise returns one. */
11682 static int
11684 {
11694 else
11696 }
11701 /* Instantiate the contract statement. */
11703 static tree
11705 tree in_decl)
11706 {
11712 /* Rebuild the result variable. */
11714 {
11722 /* Make sure the postcondition is valid. */
11728 /* Make the variable available for lookup. */
11730 }
11732 /* Instantiate the condition. If the return type is undeduced, process
11733 the expression as if inside a template to avoid spurious type errors. */
11743 /* And the comment. */
11748 }
11750 /* Update T by instantiating its contract attribute. */
11752 static void
11755 {
11756 /* For non-specializations, adjust the current declaration to the most general
11757 version of in_decl. Because we defer the instantiation of contracts as long
11758 as possible, they are still written in terms of the parameters (and return
11759 type) of the most general template. */
11766 /* Get the contract to be instantiated. */
11769 /* Use the complete set of template arguments for instantiation. The
11770 contract may not have been instantiated and still refer to outer levels
11771 of template parameters. */
11774 /* For member functions, make this available for semantic analysis. */
11778 {
11782 }
11789 /* Rebuild the attribute. */
11791 }
11793 /* Rebuild the attribute list for DECL, substituting into contracts
11794 as needed. */
11796 void
11798 {
11801 {
11804 }
11806 }
11808 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
11809 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
11811 static tree
11814 {
11817 /* Note that contract attributes are never substituted from this function.
11818 Their instantiation is triggered by regenerate_from_template_decl when
11819 we instantiate the body of the function. */
11827 {
11834 clauses
11838 else
11840 }
11844 {
11855 {
11859 {
11861 {
11869 }
11870 else
11871 {
11875 {
11876 bool allow_string
11888 {
11889 location_t loc
11891 match_loc);
11897 "integer expression or string "
11899 else
11903 }
11906 {
11907 location_t loc
11909 match_loc);
11913 }
11915 }
11916 }
11917 }
11918 }
11920 }
11921 /* If the first attribute argument is an identifier, don't
11922 pass it through tsubst. Attributes like mode, format,
11923 cleanup and several target specific attributes expect it
11924 unmodified. */
11926 {
11927 tree chain
11931 }
11933 {
11934 /* An attribute pack expansion. */
11943 {
11947 }
11949 }
11950 else
11958 }
11960 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
11961 unchanged or a new TREE_LIST chain. */
11963 static tree
11966 {
11971 {
11975 }
11979 {
11982 {
11985 {
11991 }
11992 }
11994 }
11997 }
11999 /* Apply any attributes which had to be deferred until instantiation
12000 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
12001 ARGS, COMPLAIN, IN_DECL are as tsubst. Returns true normally,
12002 false on error. */
12004 static bool
12007 {
12008 tree t;
12015 {
12019 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
12020 to our attributes parameter. */
12022 }
12023 else
12024 {
12026 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
12027 lookup_template_class_1, and should be preserved. */
12031 }
12033 /* save_template_attributes puts the dependent attributes at the beginning of
12034 the list; find the non-dependent ones. */
12040 /* Apply any non-dependent attributes. */
12046 /* And then any dependent ones. */
12050 {
12055 {
12058 }
12061 }
12063 /* cplus_decl_attributes can add some attributes implicitly. For templates,
12064 those attributes should have been added already when those templates were
12065 parsed, and shouldn't be added based on from which context they are
12066 first time instantiated. */
12069 optimization_default_node);
12072 NULL);
12078 }
12080 /* The template TMPL is being instantiated with the template arguments TARGS.
12081 Perform the access checks that we deferred when parsing the template. */
12083 static void
12085 {
12095 {
12103 /* Make access check error messages point to the location
12104 of the use of the typedef. */
12108 }
12109 }
12111 tree
12113 {
12117 tree typedecl;
12118 tree pbinfo;
12119 tree base_list;
12121 tree fn_context;
12131 /* Figure out which template is being instantiated. */
12135 /* Mark the type as in the process of being defined. */
12138 /* We may be in the middle of deferred access check. Disable
12139 it now. */
12142 /* Determine what specialization of the original template to
12143 instantiate. */
12148 {
12149 /* This TYPE is actually an instantiation of a partial
12150 specialization. We replace the innermost set of ARGS with
12151 the arguments appropriate for substitution. For example,
12152 given:
12154 template <class T> struct S {};
12155 template <class T> struct S<T*> {};
12157 and supposing that we are instantiating S<int*>, ARGS will
12158 presently be {int*} -- but we need {int}. */
12161 }
12162 else
12163 {
12166 }
12168 /* If the template we're instantiating is incomplete, then clearly
12169 there's nothing we can do. */
12171 {
12172 /* We can try again later. */
12175 }
12177 /* If we've recursively instantiated too many templates, stop. */
12185 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
12190 else
12191 {
12194 }
12198 /* Use #pragma pack from the template context. */
12204 /* Set the input location to the most specialized template definition.
12205 This is needed if tsubsting causes an error. */
12219 {
12222 /* Adjust visibility for template arguments. */
12224 }
12230 /* We should never instantiate a nested class before its enclosing
12231 class; we need to look up the nested class by name before we can
12232 instantiate it, and that lookup should instantiate the enclosing
12233 class. */
12238 /* Defer access checking while we substitute into the types named in
12239 the base-clause. */
12242 {
12243 tree pbase_binfo;
12246 /* Substitute into each of the bases to determine the actual
12247 basetypes. */
12249 {
12250 tree base;
12256 {
12257 expanded_bases =
12264 }
12267 {
12269 /* Extract the already-expanded base class. */
12271 else
12272 /* Substitute to figure out the base class. */
12274 NULL_TREE);
12282 }
12283 }
12285 /* The list is now in reverse order; correct that. */
12287 }
12288 /* Now call xref_basetypes to set up all the base-class
12289 information. */
12297 /* Now that our base classes are set up, enter the scope of the
12298 class, so that name lookups into base classes, etc. will work
12299 correctly. This is precisely analogous to what we do in
12300 begin_class_definition when defining an ordinary non-template
12301 class, except we also need to push the enclosing classes. */
12304 /* Now check accessibility of the types named in its base-clause,
12305 relative to the scope of the class. */
12308 /* A vector to hold members marked with attribute used. */
12311 /* Now members are processed in the order of declaration. */
12314 {
12318 {
12320 {
12322 /* A closure type for a lambda in an NSDMI or default argument.
12323 Ignore it; it will be regenerated when needed. */
12326 /* If the member is a class template, we've
12327 already substituted its type. */
12337 {
12340 /* Now, install the tag. We don't use pushtag
12341 because that does too much work -- creating an
12342 implicit typedef, which we've already done. */
12347 }
12348 }
12350 {
12351 tree r;
12361 /* Instantiate members marked with attribute used. */
12367 }
12370 /* A closure type for a lambda in an NSDMI or default argument.
12372 else
12373 {
12374 /* Build new TYPE_FIELDS. */
12378 {
12379 tree r;
12384 /* The file and line for this declaration, to
12385 assist in error message reporting. Since we
12386 called push_tinst_level above, we don't need to
12387 restore these. */
12397 {
12398 /* A capture pack became multiple fields. */
12401 }
12404 {
12408 {
12409 /* In [temp.inst]:
12411 [t]he initialization (and any associated
12412 side-effects) of a static data member does
12413 not occur unless the static data member is
12414 itself used in a way that requires the
12415 definition of the static data member to
12416 exist.
12418 Therefore, we do not substitute into the
12419 initialized for the static data member here. */
12420 finish_static_data_member_decl
12426 /* Instantiate members marked with attribute used. */
12429 }
12431 {
12432 /* Determine whether R has a valid type and can be
12433 completed later. If R is invalid, then its type
12434 is replaced by error_mark_node. */
12440 {
12441 /* If R's type couldn't be completed and
12442 it isn't a flexible array member (whose
12443 type is incomplete by definition) give
12444 an error. */
12447 }
12452 {
12455 }
12459 }
12461 /* If it is a TYPE_DECL for a class-scoped
12462 ENUMERAL_TYPE, such a thing will already have
12463 been added to the field list by tsubst_enum
12464 in finish_member_declaration case above. */
12468 {
12471 }
12472 }
12473 }
12474 }
12475 }
12476 else
12477 {
12480 {
12481 /* Build new CLASSTYPE_FRIEND_CLASSES. */
12485 {
12486 /* template <class T> friend class C; */
12488 }
12490 {
12491 /* template <class T> friend class C::D; */
12496 }
12499 {
12500 /* This could be either
12502 friend class T::C;
12504 when dependent_type_p is false or
12506 template <class U> friend class T::C;
12508 otherwise. */
12509 /* Bump processing_template_decl in case this is something like
12510 template <class T> friend struct A<T>::B. */
12515 }
12517 /* friend class C<T>; */
12521 /* Otherwise it's
12523 friend class C;
12525 where C is already declared or
12527 friend class C<int>;
12529 We don't have to do anything in these cases. */
12533 }
12534 else
12535 {
12536 /* Build new DECL_FRIENDLIST. */
12537 tree r;
12539 /* The file and line for this declaration, to
12540 assist in error message reporting. Since we
12541 called push_tinst_level above, we don't need to
12542 restore these. */
12546 {
12549 }
12554 {
12557 }
12558 }
12559 }
12560 }
12563 {
12564 /* Restore these before substituting into the lambda capture
12565 initializers. */
12568 }
12570 /* Set the file and line number information to whatever is given for
12571 the class itself. This puts error messages involving generated
12572 implicit functions at a predictable point, and the same point
12573 that would be used for non-template classes. */
12580 /* Remember if instantiating this class ran into errors, so we can avoid
12581 instantiating member functions in limit_bad_template_recursion. We set
12582 this flag even if the problem was in another instantiation triggered by
12583 this one, as that will likely also cause trouble for member functions. */
12587 /* We don't instantiate default arguments for member functions. 14.7.1:
12589 The implicit instantiation of a class template specialization causes
12590 the implicit instantiation of the declarations, but not of the
12591 definitions or default arguments, of the class member functions,
12592 member classes, static data members and member templates.... */
12597 /* Now that we've gone through all the members, instantiate those
12598 marked with attribute used. We must do this in the context of
12599 the class -- not the context we pushed from, as that might be
12600 inside a template and change the behaviour of mark_used. */
12610 /* The vtable for a template class can be emitted in any translation
12611 unit in which the class is instantiated. When there is no key
12612 method, however, finish_struct_1 will already have added TYPE to
12613 the keyed_classes. */
12618 }
12620 tree
12622 {
12623 tree r;
12629 else
12630 {
12636 }
12639 }
12641 /* Given a function parameter pack TMPL_PARM and some function parameters
12642 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
12643 and set *SPEC_P to point at the next point in the list. */
12645 tree
12647 {
12648 /* Collect all of the extra "packed" parameters into an
12649 argument pack. */
12650 tree argpack;
12661 {
12662 /* The instantiation is still a parameter pack; don't wrap it in a
12663 NONTYPE_ARGUMENT_PACK. */
12666 }
12667 else
12668 {
12669 /* Fill in PARMVEC with all of the parameters. */
12673 {
12679 }
12681 /* Build the argument packs. */
12683 }
12687 }
12689 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
12690 NONTYPE_ARGUMENT_PACK. */
12692 static tree
12694 {
12696 }
12698 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
12699 pack expansion with no extra args, 2 if it has extra args, or 0
12700 if it is not a pack expansion. */
12702 static int
12704 {
12706 /* We're being called before this happens in tsubst_pack_expansion. */
12713 /* A decl pack is itself an expansion. */
12720 }
12723 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
12725 static tree
12727 {
12734 }
12736 /* This is a subroutine of tsubst_pack_expansion.
12738 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
12739 mechanism to store the (non complete list of) arguments of the
12740 substitution and return a non substituted pack expansion, in order
12741 to wait for when we have enough arguments to really perform the
12742 substitution. */
12744 static bool
12746 tree parm_packs,
12749 {
12754 /* If one pack has an expansion and another pack has a normal
12755 argument or if one pack has an empty argument and an another
12756 one hasn't then tsubst_pack_expansion cannot perform the
12757 substitution and need to fall back on the
12758 PACK_EXPANSION_EXTRA mechanism. */
12762 {
12763 /* If all the actual packs are pack expansions, we can still
12764 subsitute directly. */
12766 {
12776 }
12778 }
12781 {
12785 parm_pack;
12787 {
12792 /* We can't substitute a pack expansion with extra args into
12793 our pattern. */
12797 else
12799 }
12802 {
12805 }
12806 }
12808 }
12810 /* [temp.variadic]/6 says that:
12812 The instantiation of a pack expansion [...]
12813 produces a list E1,E2, ..., En, where N is the number of elements
12814 in the pack expansion parameters.
12816 This subroutine of tsubst_pack_expansion produces one of these Ei.
12818 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
12819 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
12820 PATTERN, and each TREE_VALUE is its corresponding argument pack.
12821 INDEX is the index 'i' of the element Ei to produce. ARGS,
12822 COMPLAIN, and IN_DECL are the same parameters as for the
12823 tsubst_pack_expansion function.
12825 The function returns the resulting Ei upon successful completion,
12826 or error_mark_node.
12828 Note that this function possibly modifies the ARGS parameter, so
12829 it's the responsibility of the caller to restore it. */
12831 static tree
12833 tree parm_packs,
12835 tree args /* This parm gets
12837 tsubst_flags_t complain,
12838 tree in_decl)
12839 {
12840 tree t;
12843 /* For each parameter pack, change the substitution of the parameter
12844 pack to the ith argument in its argument pack, then expand the
12845 pattern. */
12847 {
12852 ith_elem_is_expansion |=
12855 /* Select the Ith argument from the pack. */
12859 {
12861 {
12866 }
12867 else
12869 }
12870 else
12871 {
12876 {
12878 /* Update the corresponding argument. */
12880 }
12881 else
12882 /* Re-use the ARGUMENT_PACK_SELECT. */
12884 }
12886 }
12888 /* Substitute into the PATTERN with the (possibly altered)
12889 arguments. */
12891 /* Expanding a fixed parameter pack from
12892 coerce_template_parameter_pack. */
12898 else
12899 {
12902 /* When expanding the fake auto... pack expansion from add_capture, we
12903 need to mark that the expansion is no longer a pack. */
12905 }
12907 /* If the Ith argument pack element is a pack expansion, then
12908 the Ith element resulting from the substituting is going to
12909 be a pack expansion as well. */
12914 }
12916 /* When the unexpanded parameter pack in a fold expression expands to an empty
12917 sequence, the value of the expression is as follows; the program is
12918 ill-formed if the operator is not listed in this table.
12920 && true
12921 || false
12922 , void() */
12924 tree
12926 {
12930 {
12939 }
12945 }
12947 /* Given a fold-expression T and a current LEFT and RIGHT operand,
12948 form an expression that combines the two terms using the
12949 operator of T. */
12951 static tree
12953 {
12958 // Handle compound assignment operators.
12965 {
12974 complain);
12975 }
12976 }
12978 /* Substitute ARGS into the pack of a fold expression T. */
12982 {
12984 }
12986 /* Substitute ARGS into the pack of a fold expression T. */
12990 {
12992 }
12994 /* Expand a PACK of arguments into a grouped as left fold.
12995 Given a pack containing elements A0, A1, ..., An and an
12996 operator @, this builds the expression:
12998 ((A0 @ A1) @ A2) ... @ An
13000 Note that PACK must not be empty.
13002 The operator is defined by the original fold expression T. */
13004 static tree
13006 {
13009 {
13012 }
13014 }
13016 /* Substitute into a unary left fold expression. */
13018 static tree
13020 tree in_decl)
13021 {
13026 {
13030 }
13033 else
13035 }
13037 /* Substitute into a binary left fold expression.
13039 Do ths by building a single (non-empty) vector of argumnts and
13040 building the expression from those elements. */
13042 static tree
13044 tree in_decl)
13045 {
13054 {
13059 }
13067 }
13069 /* Expand a PACK of arguments into a grouped as right fold.
13070 Given a pack containing elementns A0, A1, ..., and an
13071 operator @, this builds the expression:
13073 A0@ ... (An-2 @ (An-1 @ An))
13075 Note that PACK must not be empty.
13077 The operator is defined by the original fold expression T. */
13079 tree
13081 {
13082 // Build the expression.
13086 {
13089 }
13091 }
13093 /* Substitute into a unary right fold expression. */
13095 static tree
13097 tree in_decl)
13098 {
13103 {
13107 }
13110 else
13112 }
13114 /* Substitute into a binary right fold expression.
13116 Do ths by building a single (non-empty) vector of arguments and
13117 building the expression from those elements. */
13119 static tree
13121 tree in_decl)
13122 {
13131 {
13136 }
13145 }
13147 /* Walk through the pattern of a pack expansion, adding everything in
13148 local_specializations to a list. */
13150 class el_data
13151 {
13153 /* Set of variables declared within the pattern. */
13155 /* Set of AST nodes that have been visited by the traversal. */
13157 /* List of local_specializations used within the pattern. */
13158 tree extra;
13159 tsubst_flags_t complain;
13160 /* True iff we don't want to walk into unevaluated contexts. */
13162 /* The unevaluated contexts that we avoided walking. */
13167 };
13168 static tree
13170 {
13177 {
13181 }
13184 /* Remember local typedefs (85214). */
13188 {
13194 {
13197 decl2
13203 {
13206 }
13207 }
13208 }
13210 {
13211 /* Since we defer implicit capture, look in the parms and body. */
13217 }
13219 {
13221 /* Don't mess with variables declared within the pattern. */
13224 {
13225 /* Maybe pull out the PARM_DECL for a partial instantiation. */
13228 {
13234 }
13236 {
13237 /* Handle lambda capture here, since we aren't doing any
13238 substitution now, and so tsubst_copy won't call
13239 process_outer_var_ref. */
13243 {
13249 {
13250 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
13251 proxies. */
13253 {
13258 }
13260 }
13261 }
13262 }
13263 }
13267 }
13269 }
13270 static tree
13272 {
13274 /* Walk the pattern twice, ignoring unevaluated operands the first time
13275 around, so that if a local specialization appears in both an evaluated
13276 and unevaluated context we prefer to process it in the evaluated context
13277 (since e.g. process_outer_var_ref is a no-op inside an unevaluated
13278 context). */
13281 /* Now walk the unevaluated contexts we skipped the first time around. */
13284 {
13287 }
13289 }
13291 /* Extract any uses of local_specializations from PATTERN and add them to ARGS
13292 for use in PACK_EXPANSION_EXTRA_ARGS. */
13294 tree
13296 {
13297 /* Make a copy of the extra arguments so that they won't get changed
13298 out from under us. */
13304 }
13306 /* Apply any local specializations from PACK_EXPANSION_EXTRA_ARGS and add the
13307 normal template args to ARGS. */
13309 tree
13311 {
13313 {
13315 {
13316 /* The partial instantiation involved local declarations collected in
13317 extract_local_specs; map from the general template to our local
13318 context. */
13324 /* else inst is already a full instantiation of the pack. */
13326 }
13329 }
13331 {
13332 /* This can happen after dependent substitution into a
13333 requires-expr or a lambda that uses constexpr if. */
13336 }
13337 else
13340 }
13342 /* Substitute ARGS into T, which is an pack expansion
13343 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
13344 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
13345 (if only a partial substitution could be performed) or
13346 ERROR_MARK_NODE if there was an error. */
13347 tree
13349 tree in_decl)
13350 {
13351 tree pattern;
13355 tree result;
13362 /* Add in any args remembered from an earlier partial instantiation. */
13367 /* Determine the argument packs that will instantiate the parameter
13368 packs used in the expansion expression. While we're at it,
13369 compute the number of arguments to be expanded and make sure it
13370 is consistent. */
13373 {
13380 {
13385 in_decl),
13386 complain);
13387 else
13390 complain);
13391 }
13393 {
13395 {
13398 parm_pack);
13400 }
13403 }
13405 {
13406 /* We know we have correct local_specializations if this
13407 expansion is at function scope, or if we're dealing with a
13408 local parameter in a requires expression; for the latter,
13409 tsubst_requires_expr set it up appropriately. */
13412 else
13413 /* We can't rely on local_specializations for a parameter
13414 name used later in a function declaration (such as in a
13415 late-specified return type). Even if it exists, it might
13416 have the wrong value for a recursive call. */
13420 {
13421 /* This parameter pack was used in an unevaluated context. Just
13422 make a dummy decl, since it's only used for its type. */
13427 /* Partial instantiation of the parm_pack, we can't build
13428 up an argument pack yet. */
13430 else
13432 }
13434 /* This argument pack isn't fully instantiated yet. */
13436 }
13438 {
13442 }
13443 else
13444 {
13453 }
13460 /* This can only happen if we forget to expand an argument
13461 pack somewhere else. Just return an error, silently. */
13462 {
13466 }
13469 {
13473 /* Don't bother trying to do a partial substitution with
13474 incomplete packs; we'll try again after deduction. */
13481 {
13486 pattern);
13487 else
13489 pattern);
13491 }
13493 /* Keep track of the parameter packs and their corresponding
13494 argument packs. */
13497 }
13498 else
13499 {
13500 /* We can't substitute for this parameter pack. We use a flag as
13501 well as the missing_level counter because function parameter
13502 packs don't have a level. */
13505 }
13506 }
13508 /* If the expansion is just T..., return the matching argument pack, unless
13509 we need to call convert_from_reference on all the elements. This is an
13510 important optimization; see c++/68422. */
13513 {
13516 /* If the argument pack is a single pack expansion, pull it out. */
13521 /* Types need no adjustment, nor does sizeof..., and if we still have
13522 some pack expansion args we won't do anything yet. */
13527 /* Also optimize expression pack expansions if we can tell that the
13528 elements won't have reference type. */
13534 /* Otherwise use the normal path so we get convert_from_reference. */
13535 }
13537 /* We cannot expand this expansion expression, because we don't have
13538 all of the argument packs we need. */
13540 {
13541 /* We got some full packs, but we can't substitute them in until we
13542 have values for all the packs. So remember these until then. */
13548 }
13550 /* If NEED_LOCAL_SPECIALIZATIONS then we're in a late-specified return
13551 type, so create our own local specializations map; the current map is
13552 either NULL or (in the case of recursive unification) might have
13553 bindings that we don't want to use or alter. */
13558 {
13559 /* There were no real arguments, we're just replacing a parameter
13560 pack with another version of itself. Substitute into the
13561 pattern and return a PACK_EXPANSION_*. The caller will need to
13562 deal with that. */
13565 else
13571 {
13572 /* This is a fake auto... pack expansion created in add_capture with
13573 _PACKS that don't appear in the pattern. Copy one over. */
13580 }
13582 }
13586 /* For each argument in each argument pack, substitute into the
13587 pattern. */
13591 {
13593 i,
13595 in_decl);
13598 {
13601 }
13602 }
13604 /* Update ARGS to restore the substitution from parameter packs to
13605 their argument packs. */
13607 {
13614 else
13615 {
13623 /* Update the corresponding argument. */
13627 else
13629 }
13630 }
13632 /* If the dependent pack arguments were such that we end up with only a
13633 single pack expansion again, there's no need to keep it in a TREE_VEC. */
13639 }
13641 /* Make an argument pack out of the TREE_VEC VEC. */
13643 static tree
13645 {
13646 tree pack;
13650 else
13651 {
13654 }
13657 }
13659 /* Return an exact copy of template args T that can be modified
13660 independently. */
13662 static tree
13664 {
13672 {
13677 }
13683 }
13685 /* Substitute ARGS into the *_ARGUMENT_PACK orig_arg. */
13687 tree
13689 tree in_decl)
13690 {
13691 /* This flag is used only during deduction, and we don't expect to
13692 substitute such ARGUMENT_PACKs. */
13695 /* Substitute into each of the arguments. */
13704 /* If we're substituting into a generic ARGUMENT_PACK for a variadic
13705 template parameter, we might be able to avoid allocating a new
13706 ARGUMENT_PACK and reuse the corresponding ARGUMENT_PACK from ARGS
13707 if the substituted result is identical to it. */
13709 {
13716 {
13719 }
13720 }
13722 tree new_arg;
13724 {
13727 }
13728 else
13729 {
13732 }
13735 }
13737 /* Substitute ARGS into the vector or list of template arguments T. */
13739 tree
13741 {
13745 /* In "sizeof(X<I>)" we need to evaluate "I". */
13746 cp_evaluated ev;
13752 /* True iff the substituted result is identical to T. */
13756 {
13758 tree new_arg;
13765 {
13766 /* Substitute into an expansion expression. */
13770 /* Add to the expanded length adjustment the number of
13771 expanded arguments. We subtract one from this
13772 measurement, because the argument pack expression
13773 itself is already counted as 1 in
13774 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
13775 the argument pack is empty. */
13777 }
13780 else
13789 }
13796 /* If ARGS and T are both multi-level, the substituted result may be
13797 identical to ARGS. */
13802 /* If T appears to be a vector of generic template arguments, the
13803 substituted result may be identical to the corresponding level
13804 from ARGS. */
13806 {
13811 }
13813 /* If the substituted result is identical to MAYBE_REUSE, return
13814 it and avoid allocating a new TREE_VEC, as an optimization. */
13820 /* If T consists of only a pack expansion for which substitution yielded
13821 a TREE_VEC of the expanded elements, then reuse that TREE_VEC instead
13822 of effectively making a copy. */
13828 /* Make space for the expanded arguments coming from template
13829 argument packs. */
13831 /* T can contain TREE_VECs. That happens if T contains the
13832 arguments for a member template.
13833 In that case each TREE_VEC in T represents a level of template
13834 arguments, and T won't carry any non defaulted argument count.
13835 It will rather be the nested TREE_VECs that will carry one.
13836 In other words, T carries a non defaulted argument count only
13837 if it doesn't contain any nested TREE_VEC. */
13839 {
13843 }
13847 {
13852 {
13853 /* Now expand the template argument pack "in place". */
13856 }
13857 else
13858 {
13860 out++;
13861 }
13862 }
13866 }
13868 /* Substitute ARGS into one level PARMS of template parameters. */
13870 static tree
13872 {
13879 {
13887 }
13890 }
13892 /* Return the result of substituting ARGS into the template parameters
13893 given by PARMS. If there are m levels of ARGS and m + n levels of
13894 PARMS, then the result will contain n levels of PARMS. For
13895 example, if PARMS is `template <class T> template <class U>
13896 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
13897 result will be `template <int*, double, class V>'. */
13899 static tree
13901 {
13905 /* When substituting into a template, we must set
13906 PROCESSING_TEMPLATE_DECL as the template parameters may be
13907 dependent if they are based on one-another, and the dependency
13908 predicates are short-circuit outside of templates. */
13915 {
13924 }
13929 }
13931 /* Return the result of substituting ARGS into one template parameter
13932 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
13933 parameter and which TREE_PURPOSE is the default argument of the
13934 template parameter. */
13936 static tree
13938 {
13961 }
13963 /* Substitute in-place the TEMPLATE_PARM_CONSTRAINTS of each template
13964 parameter in PARMS for sake of declaration matching. */
13966 static void
13968 tsubst_flags_t complain)
13969 {
13972 {
13978 }
13980 }
13982 /* Substitute the ARGS into the indicated aggregate (or enumeration)
13983 type T. If T is not an aggregate or enumeration type, it is
13984 handled as if by tsubst. IN_DECL is as for tsubst. If
13985 ENTERING_SCOPE is nonzero, T is the context for a template which
13986 we are presently tsubst'ing. Return the substituted value. */
13988 static tree
13990 tree args,
13991 tsubst_flags_t complain,
13992 tree in_decl,
13994 {
13998 /* Handle typedefs via tsubst so that they get consistently reused. */
14000 {
14005 /* The effect of entering_scope is that for a dependent specialization
14006 A<T>, lookup_template_class prefers to return A's primary template
14007 type instead of the implicit instantiation. So when entering_scope,
14008 we mirror this behavior by inspecting TYPE_CANONICAL appropriately,
14009 taking advantage of the fact that lookup_template_class links the two
14010 types by setting TYPE_CANONICAL of the latter to the former. */
14018 }
14021 {
14029 }
14030 }
14032 /* The part of tsubst_aggr_type that's shared with the RECORD_, UNION_
14033 and ENUMERAL_TYPE cases of tsubst. */
14035 static tree
14037 tree args,
14038 tsubst_flags_t complain,
14039 tree in_decl,
14041 {
14043 {
14046 /* Figure out what arguments are appropriate for the
14047 type we are trying to find. For example, given:
14049 template <class T> struct S;
14050 template <class T, class U> void f(T, U) { S<U> su; }
14052 and supposing that we are instantiating f<int, double>,
14053 then our ARGS will be {int, double}, but, when looking up
14054 S we only want {double}. */
14063 }
14064 else
14065 /* This is not a template type, so there's nothing to do. */
14067 }
14069 /* Map from a FUNCTION_DECL to a vec of default argument instantiations,
14070 indexed in reverse order of the parameters. */
14074 /* Return a reference to the vec* of defarg insts for FN. */
14078 {
14082 tree_vec_map **slot
14085 {
14088 }
14090 }
14092 /* Substitute into the default argument ARG (a default argument for
14093 FN), which has the indicated TYPE. */
14095 tree
14097 tsubst_flags_t complain)
14098 {
14101 /* This can happen in invalid code. */
14105 /* Shortcut {}. */
14120 /* Remember the location of the pointer to the vec rather than the location
14121 of the particular element, in case the vec grows in tsubst_expr. */
14123 /* Index in reverse order to avoid allocating space for initial parameters
14124 that don't have default arguments. */
14131 /* This default argument came from a template. Instantiate the
14132 default argument here, not in tsubst. In the case of
14133 something like:
14135 template <class T>
14136 struct S {
14137 static T t();
14138 void f(T = t());
14139 };
14141 we must be careful to do name lookup in the scope of S<T>,
14142 rather than in the current class. */
14146 /* So in_immediate_context knows this is a default argument. */
14150 /* The default argument expression may cause implicitly defined
14151 member functions to be synthesized, which will result in garbage
14152 collection. We must treat this situation as if we were within
14153 the body of function so as to avoid collecting live data on the
14154 stack. */
14161 /* Make sure the default argument is reasonable. */
14178 }
14180 /* Substitute into all the default arguments for FN. */
14182 static void
14184 {
14185 tree arg;
14186 tree tmpl_args;
14190 /* If this function is not yet instantiated, we certainly don't need
14191 its default arguments. */
14194 /* Don't do this again for clones. */
14200 arg;
14206 complain);
14207 }
14209 /* Hash table mapping a FUNCTION_DECL to its dependent explicit-specifier. */
14212 /* Store a pair to EXPLICIT_SPECIFIER_MAP. */
14214 void
14216 {
14221 }
14223 /* Lookup an element in EXPLICIT_SPECIFIER_MAP. */
14225 tree
14227 {
14229 }
14231 /* Given T, a FUNCTION_TYPE or METHOD_TYPE, construct and return a corresponding
14232 FUNCTION_TYPE or METHOD_TYPE whose return type is RETURN_TYPE, argument types
14233 are ARG_TYPES, and exception specification is RAISES, and otherwise is
14234 identical to T. */
14236 static tree
14239 {
14242 tree new_type;
14244 {
14247 }
14248 else
14249 {
14251 /* Don't pick up extra function qualifiers from the basetype. */
14254 {
14255 /* [temp.deduct]
14257 Type deduction may fail for any of the following
14258 reasons:
14260 -- Attempting to create "pointer to member of T" when T
14261 is not a class type. */
14264 r);
14266 }
14270 }
14276 }
14278 /* Check if the function type of DECL, a FUNCTION_DECL, agrees with the type of
14279 each of its formal parameters. If there is a disagreement then rebuild
14280 DECL's function type according to its formal parameter types, as part of a
14281 resolution for Core issues 1001/1322. */
14283 static void
14285 {
14288 {
14291 {
14295 {
14298 }
14302 }
14303 }
14314 {
14319 }
14321 {
14331 }
14339 }
14341 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
14343 static tree
14346 {
14351 /* Nobody should be tsubst'ing into non-template functions. */
14356 {
14359 }
14361 {
14362 /* If T is not dependent, just return it. */
14367 /* A non-templated friend doesn't get DECL_TEMPLATE_INFO. */
14371 /* Calculate the most general template of which R is a
14372 specialization. */
14375 /* We're substituting a lambda function under tsubst_lambda_expr but not
14376 directly from it; find the matching function we're already inside.
14377 But don't do this if T is a generic lambda with a single level of
14378 template parms, as in that case we're doing a normal instantiation. */
14384 /* Calculate the complete set of arguments used to
14385 specialize R. */
14387 {
14389 (DECL_TEMPLATE_RESULT
14395 /* Check to see if we already have this specialization. */
14397 {
14400 /* The spec for these args might be a partial instantiation of the
14401 template, but here what we want is the FUNCTION_DECL. */
14403 }
14404 }
14405 else
14407 }
14408 else
14409 {
14410 /* This special case arises when we have something like this:
14412 template <class T> struct S {
14413 friend void f<int>(int, double);
14414 };
14416 Here, the DECL_TI_TEMPLATE for the friend declaration
14417 will be an IDENTIFIER_NODE. We are being called from
14418 tsubst_friend_function, and we want only to create a
14419 new decl (R) with appropriate types so that we can call
14420 determine_specialization. */
14421 friend_case:
14424 }
14431 /* If this is a static lambda, remove the 'this' pointer added in
14432 tsubst_lambda_expr now that we know the closure type. */
14446 /* If we hit excessive deduction depth, the type is bogus even if
14447 it isn't error_mark_node, so don't build a decl. */
14451 /* We do NOT check for matching decls pushed separately at this
14452 point, as they may not represent instantiations of this
14453 template, and in any case are considered separate under the
14454 discrete model. */
14458 /* Clear out the mangled name and RTL for the instantiation. */
14461 /* Leave DECL_INITIAL set on deleted instantiations. */
14467 /* Handle explicit(dependent-expr). */
14469 {
14477 else
14478 {
14481 }
14482 }
14484 /* OpenMP UDRs have the only argument a reference to the declared
14485 type. We want to diagnose if the declared type is a reference,
14486 which is invalid, but as references to references are usually
14487 quietly merged, diagnose it here. */
14489 {
14490 tree argtype
14495 "reference type %qT in "
14499 argtype);
14500 }
14503 /* Type-conversion operator. Reconstruct the name, in
14504 case it's the name of one of the template's parameters. */
14514 {
14519 }
14528 /* If this is an instantiation of a function with internal
14529 linkage, we already know what object file linkage will be
14530 assigned to the instantiation. */
14539 /* We'll re-clone as appropriate in instantiate_template. */
14542 /* If we aren't complaining now, return on error before we register
14543 the specialization so that we'll complain eventually. */
14549 /* Associate the constraints directly with the instantiation. We
14550 don't substitute through the constraints; that's only done when
14551 they are checked. */
14564 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
14565 this in the special friend case mentioned above where
14566 GEN_TMPL is NULL. */
14568 {
14574 {
14575 tree new_r
14578 /* We instantiated this while substituting into
14579 the type earlier (template/friend54.C). */
14581 }
14583 /* We're not supposed to instantiate default arguments
14584 until they are called, for a template. But, for a
14585 declaration like:
14587 template <class T> void f ()
14588 { extern void g(int i = T()); }
14590 we should do the substitution when the template is
14591 instantiated. We handle the member function case in
14592 instantiate_class_template since the default arguments
14593 might refer to other members of the class. */
14598 }
14600 {
14603 }
14604 else
14607 /* Copy the list of befriending classes. */
14611 {
14615 }
14618 {
14622 /* If this is an instantiation of a member template, clone it.
14623 If it isn't, that'll be handled by
14624 clone_constructors_and_destructors. */
14627 }
14633 /* Possibly limit visibility based on template args. */
14636 {
14640 }
14652 }
14654 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
14656 static tree
14659 {
14660 /* We can get here when processing a member function template,
14661 member class template, or template template parameter. */
14664 tree spec;
14665 tree tmpl_args;
14666 tree full_args;
14667 tree r;
14671 {
14672 /* Template template parameter is treated here. */
14676 /* If we get a real template back, return it. This can happen in
14677 the context of most_specialized_partial_spec. */
14680 else
14681 /* The new TEMPLATE_DECL was built in
14682 reduce_template_parm_level. */
14685 }
14688 {
14689 /* We might already have an instance of this template.
14690 The ARGS are for the surrounding class type, so the
14691 full args contain the tsubst'd args for the context,
14692 plus the innermost args from the template decl. */
14696 /* Because this is a template, the arguments will still be
14697 dependent, even after substitution. If
14698 PROCESSING_TEMPLATE_DECL is not set, the dependency
14699 predicates will short-circuit. */
14707 /* If this is a default template template argument,
14708 tsubst might not have changed anything. */
14715 {
14717 /* Type partial instantiations are stored as the type by
14718 lookup_template_class_1, not here as the template. */
14721 }
14722 }
14724 /* Make a new template decl. It will be similar to the
14725 original, but will record the current template arguments.
14726 We also create a new function declaration, which is just
14727 like the old one, but points to this new template, rather
14728 than the old one. */
14733 // Build new template info linking to the original template decl.
14735 {
14738 }
14739 else
14742 /* The template parameters for this new template are all the
14743 template parameters for the old template, except the
14744 outermost level of parameters. */
14747 = current_template_parms
14748 = (lambda_tparms
14749 ? lambda_tparms
14751 complain));
14758 else
14759 {
14761 {
14764 }
14768 else
14770 }
14776 {
14777 /* For a partial specialization, we need to keep pointing to
14778 the primary template. */
14780 {
14783 }
14787 }
14789 {
14792 }
14793 else
14794 {
14797 }
14804 {
14805 /* Propagate module information from the decl. */
14808 /* If this is a constrained template, the above tsubst of
14809 inner can find the unconstrained template, which may have
14810 come from an import. This is ok, because we don't
14811 register this instantiation (see below). */
14813 || (TEMPLATE_PARMS_CONSTRAINTS
14815 }
14824 /* Record this non-type partial instantiation. */
14830 }
14832 /* True if FN is the op() for a lambda in an uninstantiated template. */
14834 bool
14836 {
14841 }
14843 /* True if FN is the substitution (via tsubst_lambda_expr) of a function for
14844 which the above is true. */
14846 bool
14848 {
14854 }
14856 /* Return the LAMBDA_EXPR from which T was ultimately regenerated.
14857 If T is not a regenerated LAMBDA_EXPR, return T. */
14859 tree
14861 {
14865 }
14867 /* Return the set of template arguments used to regenerate the lambda T
14868 from its most general lambda. */
14870 tree
14872 {
14878 else
14880 }
14882 /* We're instantiating a variable from template function TCTX. Return the
14883 corresponding current enclosing scope. We can match them up using
14884 DECL_SOURCE_LOCATION because lambdas only ever have one source location, and
14885 the DECL_SOURCE_LOCATION for a function instantiation is updated to match
14886 the template definition in regenerate_decl_from_template. */
14888 static tree
14890 {
14893 /* We shouldn't ever need to do this for other artificial functions. */
14900 }
14902 /* Substitute the ARGS into the T, which is a _DECL. Return the
14903 result of the substitution. Issue error and warning messages under
14904 control of COMPLAIN. The flag USE_SPEC_TABLE controls if we look up
14905 and insert into the specializations table or if we can assume it's
14906 the caller's responsibility; this is used by instantiate_template
14907 to avoid doing some redundant work. */
14909 static tree
14912 {
14913 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
14914 location_t saved_loc;
14922 /* Set the filename and linenumber to improve error-reporting. */
14927 {
14936 use_spec_table);
14940 {
14948 {
14949 /* If there is a local specialization that isn't a
14950 parameter pack, it means that we're doing a "simple"
14951 substitution from inside tsubst_pack_expansion. Just
14952 return the local specialization (which will be a single
14953 parm). */
14960 /* Expand the TYPE_PACK_EXPANSION that provides the types for
14961 the parameters in this function parameter pack. */
14965 {
14968 /* Zero-length parameter packs are boring. Just substitute
14969 into the chain. */
14973 }
14974 else
14975 {
14976 /* All we did was update the type. Make a note of that. */
14979 }
14980 }
14982 /* Loop through all of the parameters we'll build. When T is
14983 a function parameter pack, LEN is the number of expanded
14984 types in EXPANDED_TYPES; otherwise, LEN is 1. */
14987 {
14994 /* We're on the Ith parameter of the function parameter
14995 pack. */
14996 {
14997 /* Get the Ith type. */
15000 /* Rename the parameter to include the index. */
15003 }
15005 /* We're dealing with a normal parameter. */
15013 {
15016 else
15019 }
15030 /* Keep track of the first new parameter we
15031 generate. That's what will be returned to the
15032 caller. */
15036 /* Build a proper chain of parameters when substituting
15037 into a function parameter pack. */
15040 }
15042 /* If cp_unevaluated_operand is set, we're just looking for a
15043 single dummy parameter, so don't keep going. */
15048 /* FIRST_R contains the start of the chain we've built. */
15050 }
15054 {
15061 {
15062 /* This field is a lambda capture pack. Return a TREE_VEC of
15063 the expanded fields to instantiate_class_template_1. */
15067 {
15070 }
15071 else
15072 {
15073 /* All we did was update the type. Make a note of that. */
15076 }
15077 }
15080 {
15083 {
15087 }
15097 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
15098 number of bits. */
15103 {
15104 /* Set up DECL_TEMPLATE_INFO so that we can get at the
15105 NSDMI in perform_member_init. Still set DECL_INITIAL
15106 so that we know there is one. */
15111 }
15112 /* We don't have to set DECL_CONTEXT here; it is set by
15113 finish_member_declaration. */
15122 }
15126 }
15130 /* We reach here only for member using decls. We also need to check
15131 uses_template_parms because DECL_DEPENDENT_P is not set for a
15132 using-declaration that designates a member of the current
15133 instantiation (c++/53549). */
15136 {
15137 /* True iff this using-decl was written as a pack expansion
15138 (and a pack appeared in its scope or name). If a pack
15139 appeared in both, we expand the packs separately and
15140 manually merge them. */
15145 {
15148 in_decl);
15150 }
15151 else
15157 {
15161 {
15164 }
15168 }
15169 else
15177 {
15179 {
15184 }
15186 }
15194 {
15203 {
15206 }
15210 }
15214 }
15215 else
15216 {
15219 }
15224 {
15235 {
15236 /* If this is the canonical decl, we don't have to
15237 mess with instantiations, and often we can't (for
15238 typename, template type parms and such). Note that
15239 TYPE_NAME is not correct for the above test if
15240 we've copied the type for a typedef. */
15246 }
15248 /* Check to see if we already have the specialization we
15249 need. */
15255 {
15258 {
15260 complain,
15263 /* The context and type of an injected-class-name are
15264 the same, so we don't need to substitute both. */
15266 /* If CTX is unchanged, then T is in fact the
15267 specialization we want. That situation occurs when
15268 referencing a static data member within in its own
15269 class. We can use pointer equality, rather than
15270 same_type_p, because DECL_CONTEXT is always
15271 canonical... */
15273 /* ... unless T is a member template; in which
15274 case our caller can be willing to create a
15275 specialization of that template represented
15276 by T. */
15280 }
15283 {
15286 {
15293 }
15294 else
15296 }
15297 }
15298 else
15299 {
15301 /* Subsequent calls to pushdecl will fill this in. */
15303 /* A local variable. */
15305 /* Unless this is a reference to a static variable from an
15306 enclosing function, in which case we need to fill it in now. */
15308 {
15312 }
15314 }
15315 /* If we already have the specialization we need, there is
15316 nothing more to do. */
15318 {
15321 }
15323 /* Create a new node for the specialization we need. */
15325 {
15328 else
15338 /* Substituting the type might have recursively instantiated this
15339 same alias (c++/86171). */
15342 {
15345 }
15346 }
15351 {
15355 {
15356 /* It may seem that this case cannot occur, since:
15358 typedef void f();
15359 void g() { f x; }
15361 declares a function, not a variable. However:
15363 typedef void f();
15364 template <typename T> void g() { T t; }
15365 template void g<f>();
15367 is an attempt to declare a variable with function
15368 type. */
15370 /* R is not yet sufficiently initialized, so we
15371 just use its name. */
15374 }
15376 /* Wait until cp_finish_decl to set this again, to handle
15377 circular dependency (template/instantiate6.C). */
15382 {
15384 /* If the DECL_VALUE_EXPR is converted to the declared type,
15385 preserve the identity so that gimplify_type_sizes works. */
15391 {
15394 }
15403 else
15407 }
15411 }
15417 /* Clear out the mangled name and RTL for the instantiation. */
15423 /* The initializer must not be expanded until it is required;
15424 see [temp.inst]. */
15428 {
15434 /* Possibly limit visibility based on template args. */
15437 {
15441 }
15443 }
15446 {
15447 /* A static data member declaration is always marked
15448 external when it is declared in-class, even if an
15449 initializer is present. We mimic the non-template
15450 processing here. */
15459 }
15460 else
15461 {
15466 }
15475 /* Preserve a typedef that names a type. */
15477 {
15481 /* common_handle_aligned_attribute doesn't apply the alignment
15482 to DECL_ORIGINAL_TYPE. */
15486 }
15489 }
15494 }
15495 #undef RETURN
15497 out:
15498 /* Restore the file and line information. */
15502 }
15504 /* Substitute into the complete parameter type list PARMS. */
15506 tree
15508 tree args,
15509 tsubst_flags_t complain,
15510 tree in_decl)
15511 {
15513 }
15515 /* Substitute into the ARG_TYPES of a function type.
15516 If END is a TREE_CHAIN, leave it and any following types
15517 un-substituted. */
15519 static tree
15521 tree args,
15522 tree end,
15523 tsubst_flags_t complain,
15524 tree in_decl)
15525 {
15534 {
15535 /* For a pack expansion, perform substitution on the
15536 entire expression. Later on, we'll handle the arguments
15537 one-by-one. */
15542 /* So that we'll spin through the parameters, one by one. */
15544 else
15545 {
15546 /* We only partially substituted into the parameter
15547 pack. Our type is TYPE_PACK_EXPANSION. */
15550 }
15551 }
15552 else
15555 /* Check if a substituted type is erroneous before substituting into
15556 the rest of the chain. */
15558 {
15565 {
15567 {
15571 }
15573 }
15574 }
15576 /* We do not substitute into default arguments here. The standard
15577 mandates that they be instantiated only when needed, which is
15578 done in build_over_call. */
15581 /* Except that we do substitute default arguments under tsubst_lambda_expr,
15582 since the new op() won't have any associated template arguments for us
15583 to refer to later. */
15595 {
15599 /* Do array-to-pointer, function-to-pointer conversion, and ignore
15600 top-level qualifiers as required. */
15604 {
15605 /* We've instantiated a template before its default arguments
15606 have been parsed. This can happen for a nested template
15607 class, and is not an error unless we require the default
15608 argument in a call of this function. */
15609 remaining_arg_types
15612 remaining_arg_types);
15613 }
15614 else
15615 remaining_arg_types
15617 }
15620 }
15622 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
15623 *not* handle the exception-specification for FNTYPE, because the
15624 initial substitution of explicitly provided template parameters
15625 during argument deduction forbids substitution into the
15626 exception-specification:
15628 [temp.deduct]
15630 All references in the function type of the function template to the
15631 corresponding template parameters are replaced by the specified tem-
15632 plate argument values. If a substitution in a template parameter or
15633 in the function type of the function template results in an invalid
15634 type, type deduction fails. [Note: The equivalent substitution in
15635 exception specifications is done only when the function is instanti-
15636 ated, at which point a program is ill-formed if the substitution
15637 results in an invalid type.] */
15639 static tree
15641 tree args,
15642 tsubst_flags_t complain,
15643 tree in_decl)
15644 {
15645 tree return_type;
15648 /* The TYPE_CONTEXT is not used for function/method types. */
15651 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
15652 failure. */
15656 {
15657 /* Substitute the argument types. */
15669 {
15670 /* DR 1207: 'this' is in scope in the trailing return type. */
15672 }
15674 /* Substitute the return type. */
15678 {
15681 }
15682 }
15683 else
15684 /* Substitute the return type. */
15689 /* DR 486 clarifies that creation of a function type with an
15690 invalid return type is a deduction failure. */
15693 {
15695 {
15698 else
15700 }
15702 }
15705 {
15706 /* Substitute the argument types. */
15711 }
15713 /* Construct a new type node and return it. */
15716 }
15718 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
15719 ARGS into that specification, and return the substituted
15720 specification. If there is no specification, return NULL_TREE. */
15722 static tree
15724 tree args,
15725 tsubst_flags_t complain,
15726 tree in_decl,
15728 {
15729 tree specs;
15730 tree new_specs;
15735 {
15736 /* A noexcept-specifier. */
15741 {
15742 /* Defer instantiation of noexcept-specifiers to avoid
15743 excessive instantiations (c++/49107). */
15746 {
15747 /* We already partially instantiated this member template,
15748 so combine the new args with the old. */
15753 }
15754 else
15755 {
15758 }
15759 }
15760 else
15761 {
15763 {
15765 args);
15767 }
15769 }
15771 /* We've instantiated a template before a noexcept-specifier
15772 contained therein has been parsed. This can happen for
15773 a nested template class:
15775 struct S {
15776 template<typename> struct B { B() noexcept(...); };
15777 struct A : B<int> { ... use B() ... };
15778 };
15780 where completing B<int> will trigger instantiating the
15781 noexcept, even though we only parse it at the end of S. */
15783 {
15786 }
15787 }
15789 {
15792 else
15794 {
15795 tree spec;
15800 {
15801 /* Expand the pack expansion type. */
15804 in_decl);
15810 else
15811 {
15812 /* We're substituting into a member template, so
15813 we got a TYPE_PACK_EXPANSION back. Add that
15814 expansion and move on. */
15818 expanded_specs,
15819 complain);
15822 }
15823 }
15826 {
15829 else
15834 complain);
15835 }
15838 }
15839 }
15841 }
15843 /* Substitute through a TREE_LIST of types or expressions, handling pack
15844 expansions. */
15846 tree
15848 {
15855 ;
15857 {
15861 }
15864 else
15872 ;
15874 {
15878 }
15881 else
15888 ;
15893 else
15904 /* Determine the number of arguments. */
15906 {
15909 }
15912 else
15916 {
15924 else
15926 }
15929 }
15931 /* Take the tree structure T and replace template parameters used
15932 therein with the argument vector ARGS. IN_DECL is an associated
15933 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
15934 Issue error and warning messages under control of COMPLAIN. Note
15935 that we must be relatively non-tolerant of extensions here, in
15936 order to preserve conformance; if we allow substitutions that
15937 should not be allowed, we may allow argument deductions that should
15938 not succeed, and therefore report ambiguous overload situations
15939 where there are none. In theory, we could allow the substitution,
15940 but indicate that it should have failed, and allow our caller to
15941 make sure that the right thing happens, but we don't try to do this
15942 yet.
15944 This function is used for dealing with types, decls and the like;
15945 for expressions, use tsubst_expr or tsubst_copy. */
15947 tree
15949 {
15984 /* Reuse typedefs. We need to do this to handle dependent attributes,
15985 such as attribute aligned. */
15988 {
15992 {
15993 /* DECL represents an alias template and we want to
15994 instantiate it. */
15998 }
16002 {
16006 }
16011 else
16012 /* The typedef is from a non-template context. */
16016 {
16018 r = cp_build_qualified_type
16022 }
16023 else
16024 {
16025 /* We don't have an instantiation yet, so drop the typedef. */
16030 }
16031 }
16048 {
16052 /* Fall through. */
16078 {
16083 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
16084 needed. */
16090 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
16091 with TREE_SIDE_EFFECTS that indicates this is not an integral
16092 constant expression. */
16095 {
16098 }
16101 }
16105 {
16113 else
16115 }
16116 /* Fall through. */
16120 {
16134 {
16137 /* See through ARGUMENT_PACK_SELECT arguments. */
16140 }
16145 {
16147 /* If ARG is an argument pack, we don't actually want to
16148 perform a substitution here, because substitutions
16149 for argument packs are only done
16150 element-by-element. We can get to this point when
16151 substituting the type of a non-type template
16152 parameter pack, when that type actually contains
16153 template parameter packs from an outer template, e.g.,
16155 template<typename... Types> struct A {
16156 template<Types... Values> struct B { };
16157 }; */
16161 {
16164 /* When building concept checks for the purpose of
16165 deducing placeholders, we can end up with wildcards
16166 where types are expected. Adjust this to the deduced
16167 value. */
16175 return cp_build_qualified_type
16177 }
16179 {
16180 /* We are processing a type constructed from a
16181 template template parameter. */
16192 /* Consider this code:
16194 template <template <class> class Template>
16195 struct Internal {
16196 template <class Arg> using Bind = Template<Arg>;
16197 };
16199 template <template <class> class Template, class Arg>
16200 using Instantiate = Template<Arg>; //#0
16202 template <template <class> class Template,
16203 class Argument>
16204 using Bind =
16205 Instantiate<Internal<Template>::template Bind,
16206 Argument>; //#1
16208 When #1 is parsed, the
16209 BOUND_TEMPLATE_TEMPLATE_PARM representing the
16210 parameter `Template' in #0 matches the
16211 UNBOUND_CLASS_TEMPLATE representing the argument
16212 `Internal<Template>::template Bind'; We then want
16213 to assemble the type `Bind<Argument>' that can't
16214 be fully created right now, because
16215 `Internal<Template>' not being complete, the Bind
16216 template cannot be looked up in that context. So
16217 we need to "store" `Bind<Argument>' for later
16218 when the context of Bind becomes complete. Let's
16219 store that in a TYPENAME_TYPE. */
16223 argvec),
16224 typename_type,
16225 complain);
16227 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
16228 are resolving nested-types in the signature of a
16229 member function templates. Otherwise ARG is a
16230 TEMPLATE_DECL and is the real template to be
16231 instantiated. */
16239 complain);
16240 return cp_build_qualified_type
16242 }
16245 else
16246 /* TEMPLATE_PARM_INDEX. */
16248 }
16251 /* This can happen during the attempted tsubst'ing in
16252 unify. This means that we don't yet have any information
16253 about the template parameter in question. */
16256 /* Early in template argument deduction substitution, we don't
16257 want to reduce the level of 'auto', or it will be confused
16258 with a normal template parm in subsequent deduction.
16259 Similarly, don't reduce the level of template parameters to
16260 avoid mismatches when deducing their types. */
16264 /* If we get here, we must have been looking at a parm for a
16265 more deeply nested template. Make a new version of this
16266 template parameter, but with a lower level. */
16269 {
16274 {
16277 }
16283 /* Cache lowering a type parameter or a simple template
16284 template parameter. */
16288 {
16300 /* Propagate constraints on placeholders since they are
16301 only instantiated during satisfaction. */
16306 else
16308 }
16316 {
16318 /* We might need to substitute into the types of non-type
16319 template parameters. This also lowers the level of
16320 the ttp appropriately. */
16333 }
16336 /* OK, now substitute the type of the non-type parameter. We
16337 couldn't do it earlier because it might be an auto parameter,
16338 and we wouldn't need to if we had an argument. */
16347 }
16350 }
16356 /* We should never be tsubsting a binfo. */
16360 /* A vector of template arguments. */
16366 {
16370 /* [temp.deduct]
16372 Type deduction may fail for any of the following
16373 reasons:
16375 -- Attempting to create a pointer to reference type.
16376 -- Attempting to create a reference to a reference type or
16377 a reference to void.
16379 Core issue 106 says that creating a reference to a reference
16380 during instantiation is no longer a cause for failure. We
16381 only enforce this check in strict C++98 mode. */
16385 {
16388 /* We keep track of the last time we issued this error
16389 message to avoid spewing a ton of messages during a
16390 single bad template instantiation. */
16393 {
16398 else
16401 }
16404 }
16408 {
16410 {
16413 type);
16414 else
16416 type);
16417 }
16419 }
16421 {
16425 }
16427 /* In C++0x, during template argument substitution, when there is an
16428 attempt to create a reference to a reference type, reference
16429 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
16431 "If a template-argument for a template-parameter T names a type
16432 that is a reference to a type A, an attempt to create the type
16433 'lvalue reference to cv T' creates the type 'lvalue reference to
16434 A,' while an attempt to create the type type rvalue reference to
16435 cv T' creates the type T"
16436 */
16437 r = cp_build_reference_type
16440 else
16445 /* Will this ever be needed for TYPE_..._TO values? */
16449 }
16451 {
16454 {
16455 /* [temp.deduct]
16457 Type deduction may fail for any of the following
16458 reasons:
16460 -- Attempting to create "pointer to member of T" when T
16461 is not a class type. */
16465 }
16467 {
16471 }
16473 {
16477 }
16480 {
16481 /* The type of the implicit object parameter gets its
16482 cv-qualifiers from the FUNCTION_TYPE. */
16483 tree memptr;
16484 tree method_type
16489 complain);
16490 }
16491 else
16494 complain);
16495 }
16498 {
16499 tree fntype;
16500 tree specs;
16505 /* Substitute the exception specification. */
16513 }
16515 {
16520 /* As an optimization, we avoid regenerating the array type if
16521 it will obviously be the same as T. */
16525 /* These checks should match the ones in create_array_type_for_decl.
16527 [temp.deduct]
16529 The deduction may fail for any of the following reasons:
16531 -- Attempting to create an array with an element type that
16532 is void, a function type, or a reference type, or [DR337]
16533 an abstract class type. */
16539 {
16543 }
16556 {
16559 }
16562 }
16565 {
16568 {
16571 in_decl);
16576 {
16581 }
16583 }
16584 else
16597 {
16601 }
16603 {
16604 /* Normally, make_typename_type does not require that the CTX
16605 have complete type in order to allow things like:
16607 template <class T> struct S { typename S<T>::X Y; };
16609 But, such constructs have already been resolved by this
16610 point, so here CTX really should have complete type, unless
16611 it's a partial instantiation. */
16614 }
16616 /* FIXME: TYPENAME_IS_CLASS_P conflates 'class' vs 'struct' vs 'union'
16617 tags. TYPENAME_TYPE should probably remember the exact tag that
16618 was written. */
16619 enum tag_types tag_type
16629 {
16632 }
16635 {
16637 {
16641 else
16643 }
16645 {
16649 else
16651 }
16652 }
16654 return cp_build_qualified_type
16656 }
16659 {
16671 }
16674 {
16675 tree type;
16689 complain);
16690 }
16693 {
16694 tree type;
16711 else
16712 {
16716 /* In a template ~id could be either a complement expression
16717 or an unqualified-id naming a destructor; if instantiating
16718 it produces an expression, it's not an id-expression or
16719 member access. */
16722 }
16727 }
16730 {
16734 else
16741 }
16760 /* We should use one of the expression tsubsts for these codes. */
16766 }
16767 }
16769 /* Convenience wrapper over tsubst for substituting into the LHS
16770 of the :: scope resolution operator. */
16772 static tree
16774 {
16777 }
16779 /* OLDFNS is a lookup set of member functions from some class template, and
16780 NEWFNS is a lookup set of member functions from NEWTYPE, a specialization
16781 of that class template. Return the subset of NEWFNS which are
16782 specializations of a function from OLDFNS. */
16784 static tree
16786 {
16787 /* Record all member functions from the old lookup set OLDFNS into
16788 VISIBLE_SET. */
16792 {
16794 {
16795 /* Imprecisely handle dependent using-decl by keeping all members
16796 in the new lookup set that are defined in a base class, i.e.
16797 members that could plausibly have been introduced by this
16798 dependent using-decl.
16799 FIXME: Track which members are introduced by a dependent
16800 using-decl precisely, perhaps by performing another lookup
16801 from the substituted USING_DECL_SCOPE. */
16804 }
16805 else
16807 }
16809 /* Returns true iff (a less specialized version of) FN appeared in
16810 the old lookup set OLDFNS. */
16813 /* FN is a member function from a base class, introduced via a
16814 using-decl; if it might have been introduced by a dependent
16815 using-decl then just conservatively keep it, otherwise look
16816 in the old lookup set for FN exactly. */
16819 /* FN is a member function template from the current class;
16820 look in the old lookup set for the TEMPLATE_DECL from which
16821 it was specialized. */
16823 else
16824 /* FN is a non-template member function from the current class;
16825 look in the old lookup set for the FUNCTION_DECL from which
16826 it was specialized. */
16829 };
16834 {
16837 }
16841 /* Filter out from NEWFNS the member functions that weren't
16842 previously visible according to OLDFNS. */
16847 {
16849 filtered_size++;
16850 }
16856 }
16858 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
16859 expression on the left-hand side of the "." or "->" operator. We
16860 only do the lookup if we had a dependent BASELINK. Otherwise we
16861 adjust it onto the instantiated heirarchy. */
16863 static tree
16866 {
16878 {
16885 }
16893 {
16898 /* See maybe_dependent_member_ref. */
16900 {
16903 template_args);
16906 }
16909 /* Treat as-if non-dependent below. */
16914 complain);
16916 {
16917 /* Filter out from the new lookup set those functions which didn't
16918 appear in the original lookup set (in a less specialized form).
16919 This is needed to preserve the consistency of member lookup
16920 performed in an incomplete-class context, within which
16921 later-declared members ought to remain invisible. */
16924 binfo_type);
16926 }
16929 {
16935 }
16938 }
16939 else
16940 {
16941 /* We're going to overwrite pieces below, make a duplicate. */
16945 {
16946 /* The decl we found was from non-dependent scope, but we still need
16947 to update the binfos for the instantiated qualifying_scope. */
16951 }
16952 }
16954 /* If lookup found a single function, mark it as used at this point.
16955 (If lookup found multiple functions the one selected later by
16956 overload resolution will be marked as used at that point.) */
16958 {
16964 /* We might have instantiated an auto function. */
16966 }
16969 {
16970 /* Add back the template arguments, if present. */
16975 /* Update the conversion operator type. */
16977 }
16983 {
16985 qualifying_scope,
16986 object_type);
16988 /* We need to call adjust_result_of_qualified_name_lookup in case the
16989 destructor names a base class, but we unset BASELINK_QUALIFIED_P
16990 so that we still get virtual function binding. */
16992 }
16995 }
16997 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
16998 true if the qualified-id will be a postfix-expression in-and-of
16999 itself; false if more of the postfix-expression follows the
17000 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
17001 of "&". */
17003 static tree
17007 {
17008 tree expr;
17009 tree scope;
17010 tree name;
17012 tree template_args;
17017 /* Figure out what name to look up. */
17020 {
17029 }
17030 else
17031 {
17034 }
17036 /* Substitute into the qualifying scope. When there are no ARGS, we
17037 are just trying to simplify a non-dependent expression. In that
17038 case the qualifying scope may be dependent, and, in any case,
17039 substituting will not help. */
17042 {
17045 }
17046 else
17050 {
17052 /* We built one in tsubst_baselink. */
17054 else
17055 {
17058 template_args);
17060 QUALIFIED_NAME_IS_TEMPLATE
17062 }
17065 }
17068 {
17070 {
17071 /* A BIT_NOT_EXPR is used to represent a destructor. */
17073 {
17077 }
17078 else
17081 }
17082 else
17086 {
17088 {
17092 }
17094 }
17095 }
17098 {
17102 /* Remember that there was a reference to this entity. */
17105 }
17108 {
17114 }
17117 {
17118 /* We may be repeating a check already done during parsing, but
17119 if it was well-formed and passed then, it will pass again
17120 now, and if it didn't, we wouldn't have got here. The case
17121 we want to catch is when we couldn't tell then, and can now,
17122 namely when templ prior to substitution was an
17123 identifier. */
17129 complain);
17130 else
17132 }
17138 {
17139 expr = (adjust_result_of_qualified_name_lookup
17141 expr = (finish_qualified_id_expr
17145 }
17147 /* Expressions do not generally have reference type. */
17149 /* However, if we're about to form a pointer-to-member, we just
17150 want the referenced member referenced. */
17160 }
17162 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
17163 initializer, DECL is the substituted VAR_DECL. Other arguments are as
17164 for tsubst. */
17166 static tree
17169 {
17178 {
17180 {
17182 {
17187 }
17188 }
17190 {
17191 /* If we had an initializer but it
17192 instantiated to nothing,
17193 value-initialize the object. This will
17194 only occur when the initializer was a
17195 pack expansion where the parameter packs
17196 used in that expansion were of length
17197 zero. */
17203 }
17204 }
17207 }
17209 /* If T is a reference to a dependent member of the current instantiation C and
17210 we are trying to refer to that member in a partial instantiation of C,
17211 return a SCOPE_REF; otherwise, return NULL_TREE.
17213 This can happen when forming a C++17 deduction guide, as in PR96199. */
17215 static tree
17217 tree in_decl)
17218 {
17235 {
17244 complain);
17245 }
17250 {
17256 }
17259 {
17262 /* The TYPE_DECL for a typename has DECL_CONTEXT of the typename
17263 scope, but it doesn't need to be rewritten again. */
17267 }
17271 else
17274 }
17276 /* Like tsubst, but deals with expressions. This function just replaces
17277 template parms; to finish processing the resultant expression, use
17278 tsubst_copy_and_build or tsubst_expr. */
17280 static tree
17282 {
17284 tree r;
17298 {
17303 {
17304 /* We get here for a use of 'this' in an NSDMI. */
17308 /* This can happen for a parameter name used later in a function
17309 declaration (such as in a late-specified return type). Just
17310 make a dummy decl, since it's only used for its type. */
17313 /* Give it the template pattern as its context; its true context
17314 hasn't been instantiated yet and this is good enough for
17315 mangling. */
17317 }
17326 {
17327 tree enum_type;
17328 tree v;
17335 /* Unfortunately, we cannot just call lookup_name here.
17336 Consider:
17338 template <int I> int f() {
17339 enum E { a = I };
17340 struct S { void g() { E e = a; } };
17341 };
17343 When we instantiate f<7>::S::g(), say, lookup_name is not
17344 clever enough to find f<7>::a. */
17345 enum_type
17355 /* We didn't find the name. That should never happen; if
17356 name-lookup found it during preliminary parsing, we
17357 should find it again here during instantiation. */
17359 }
17364 {
17365 tree ctx;
17370 {
17373 {
17377 }
17379 }
17380 }
17389 {
17390 /* Local specialization will usually have been created when
17391 we instantiated the DECL_EXPR_DECL. */
17394 {
17395 /* We're in a generic lambda referencing a local extern
17396 from an outer block-scope of a non-template. */
17399 }
17400 }
17403 {
17406 {
17407 /* First try name lookup to find the instantiation. */
17410 {
17412 {
17413 /* During error-recovery we may find a non-variable,
17414 even an OVERLOAD: just bail out and avoid ICEs and
17415 duplicate diagnostics (c++/62207). */
17418 }
17420 {
17421 /* Make sure the one we found is the one we want. */
17425 }
17426 }
17430 else
17431 {
17432 /* This can happen for a variable used in a
17433 late-specified return type of a local lambda, or for a
17434 local static or constant. Building a new VAR_DECL
17435 should be OK in all those cases. */
17438 /* Avoid infinite recursion (79640). */
17441 {
17442 /* We can't call cp_finish_decl, so handle the
17443 initializer by hand. */
17458 }
17460 || processing_contract_condition
17467 }
17468 /* Remember this for subsequent uses. */
17471 }
17474 }
17475 else
17499 {
17500 /* Template template argument like the following example need
17501 special treatment:
17503 template <template <class> class TT> struct C {};
17504 template <class T> struct D {
17505 template <class U> struct E {};
17506 C<E> c; // #1
17507 };
17508 D<int> d; // #2
17510 We are processing the template argument `E' in #1 for
17511 the template instantiation #2. Originally, `E' is a
17512 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
17513 have to substitute this with one having context `D<int>'. */
17518 }
17519 else
17520 /* Ordinary template template argument. */
17525 {
17526 /* Handle location wrappers by substituting the wrapped node
17527 first, *then* reusing the resulting type. Doing the type
17528 first ensures that we handle template parameters and
17529 parameter pack expansions. */
17531 {
17535 }
17537 /* force_paren_expr can also create a VIEW_CONVERT_EXPR. */
17539 {
17544 }
17545 /* We shouldn't see any other uses of these in templates
17546 (tsubst_copy_and_build handles C++20 tparm object wrappers). */
17548 }
17556 CASE_CONVERT:
17557 {
17564 }
17567 {
17573 }
17578 {
17587 /* We only want to compute the number of arguments. */
17590 else
17597 {
17599 /* Set TREE_USED for the benefit of -Wunused. */
17603 }
17611 {
17616 else
17624 else
17629 }
17630 else
17632 }
17634 {
17642 }
17643 /* Fall through */
17659 {
17665 /* For addresses of immediate functions ensure we have EXPR_LOCATION
17666 set for possible later diagnostics. */
17673 }
17676 {
17680 {
17683 }
17685 }
17688 {
17689 tree object;
17690 tree name;
17695 {
17699 }
17702 {
17712 }
17717 in_decl);
17718 else
17721 }
17757 {
17761 }
17764 {
17769 }
17772 {
17776 }
17779 {
17787 }
17793 {
17800 }
17803 {
17810 }
17813 {
17820 }
17823 {
17824 /* Substituted template arguments */
17834 else
17836 }
17839 {
17859 }
17867 /* Fall through. */
17870 {
17873 }
17874 else
17878 /* This is handled by tsubst_copy_and_build. */
17882 {
17886 }
17889 /* We shouldn't have built any of these during initial template
17890 generation. Instead, they should be built during instantiation
17891 in response to the saved STMT_IS_FULL_EXPR_P setting. */
17895 {
17905 }
17923 {
17924 /* Instantiate any typedefs in the type. */
17929 }
17932 {
17936 {
17939 }
17941 }
17944 /* These can sometimes show up in a partial instantiation, but never
17945 involve template parms. */
17961 /* ??? There's no point in copying it for now, but maybe some
17962 day it will contain more information, such as a pointer back
17963 to the containing function, inlined copy or so. */
17970 /* We shouldn't get here, but keep going if !flag_checking. */
17974 }
17975 }
17977 /* Helper function for tsubst_omp_clauses, used for instantiation of
17978 OMP_CLAUSE_DECL of clauses. */
17980 static tree
17983 {
17987 /* Handle OpenMP iterators. */
17991 {
17992 tree ret;
17995 else
17996 {
18000 {
18014 }
18018 }
18022 }
18024 /* Handle an OpenMP array section represented as a TREE_LIST (or
18025 OMP_CLAUSE_DOACROSS_KIND). An OMP_CLAUSE_DOACROSS (with a depend
18026 kind of OMP_CLAUSE_DOACROSS_SINK) can also be represented as a
18027 TREE_LIST. We can handle it exactly the same as an array section
18028 (purpose, value, and a chain), even though the nomenclature
18029 (low_bound, length, etc) is different. */
18031 {
18032 tree low_bound
18045 }
18047 /* Undo convert_from_reference tsubst_expr could have called. */
18053 }
18055 /* Like tsubst_copy, but specifically for OpenMP clauses. */
18057 static tree
18060 {
18066 {
18072 {
18075 {
18081 }
18082 /* FALLTHRU */
18112 /* FALLTHRU */
18145 {
18148 {
18155 }
18156 else
18158 }
18185 {
18188 }
18193 else
18224 }
18227 {
18244 /* tsubst_expr on SCOPE_REF results in returning
18245 finish_non_static_data_member result. Undo that here. */
18249 {
18254 {
18258 CASE_CONVERT:
18267 /* FALLTHRU */
18271 }
18272 }
18278 {
18281 {
18284 }
18285 }
18289 }
18290 }
18294 {
18299 {
18302 }
18303 }
18305 }
18307 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
18309 static tree
18311 tree in_decl)
18312 {
18313 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
18331 {
18334 else
18335 {
18339 }
18340 }
18345 #undef RECUR
18346 }
18348 /* Used to temporarily communicate the list of #pragma omp parallel
18349 clauses to #pragma omp for instantiation if they are combined
18350 together. */
18357 /* Substitute one OMP_FOR iterator. */
18359 static bool
18363 {
18364 #define RECUR(NODE) \
18365 tsubst_expr ((NODE), args, complain, in_decl)
18377 {
18380 {
18385 {
18395 else
18397 {
18399 {
18405 }
18408 }
18409 }
18410 }
18414 }
18416 {
18417 /* We need to jump through some hoops to handle declarations in the
18418 init-statement, since we might need to handle auto deduction,
18419 but we need to keep control of initialization. */
18423 }
18424 else
18425 {
18427 {
18430 {
18434 {
18438 CASE_CONVERT:
18446 {
18449 }
18450 /* FALLTHRU */
18454 }
18455 }
18456 }
18457 else
18459 }
18461 {
18467 }
18468 else
18472 {
18478 NULL_TREE);
18479 else
18481 }
18484 {
18491 {
18496 }
18499 }
18509 {
18511 {
18512 /* Declare the variable, but don't let that initialize it. */
18517 }
18520 {
18524 {
18533 }
18534 else
18538 {
18543 }
18544 else
18548 }
18554 }
18557 {
18558 /* Declare and initialize the variable. */
18561 }
18563 {
18568 {
18570 {
18576 {
18579 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
18584 }
18587 {
18589 decl);
18591 }
18594 {
18596 decl);
18598 }
18599 else
18601 }
18604 }
18606 {
18609 ? OMP_CLAUSE_LASTPRIVATE
18614 {
18617 }
18618 }
18619 }
18622 {
18626 }
18627 else
18631 {
18642 {
18650 }
18651 else
18657 {
18663 }
18667 {
18675 }
18676 else
18682 }
18691 #undef RECUR
18692 }
18694 /* Helper function of tsubst_expr, find OMP_TEAMS inside
18695 of OMP_TARGET's body. */
18697 static tree
18699 {
18702 {
18711 }
18713 }
18715 /* Helper function for tsubst_expr. For decomposition declaration
18716 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
18717 also the corresponding decls representing the identifiers
18718 of the decomposition declaration. Return DECL if successful
18719 or error_mark_node otherwise, set *FIRST to the first decl
18720 in the list chained through DECL_CHAIN and *CNT to the number
18721 of such decls. */
18723 static tree
18727 {
18732 decl2
18737 {
18739 {
18742 }
18754 else
18755 {
18759 }
18766 {
18769 }
18770 else
18772 }
18775 }
18777 /* Return the proper local_specialization for init-capture pack DECL. */
18779 static tree
18781 {
18782 /* We handle normal pack captures by forwarding to the specialization of the
18783 captured parameter. We can't do that for pack init-captures; we need them
18784 to have their own local_specialization. We created the individual
18785 VAR_DECLs (if any) under build_capture_proxy, and we need to collect them
18786 when we process the DECL_EXPR for the pack init-capture in the template.
18787 So, how do we find them? We don't know the capture proxy pack when
18788 building the individual resulting proxies, and we don't know the
18789 individual proxies when instantiating the pack. What we have in common is
18790 the FIELD_DECL.
18792 So...when we instantiate the FIELD_DECL, we stick the result in
18793 local_specializations. Then at the DECL_EXPR we look up that result, see
18794 how many elements it has, synthesize the names, and look them up. */
18808 {
18813 }
18815 {
18820 else
18822 }
18824 }
18826 /* T is an operand of a template tree being substituted. Return whether
18827 T is dependent such that we should suppress some warnings that would
18828 make sense if the substituted expression were written directly, like
18829 template <int I> bool f() { return I == 2; }
18830 We don't want to warn when instantiating f that comparing two constants
18831 always has the same value.
18833 This is a more limited concept of dependence than instantiation-dependent;
18834 here we don't care whether substitution could fail. */
18836 static bool
18838 {
18847 }
18849 /* Like tsubst_copy for expressions, etc. but also does semantic
18850 processing. */
18852 tree
18854 {
18855 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
18856 #define RECUR(NODE) \
18857 tsubst_expr ((NODE), args, complain, in_decl)
18860 tree r;
18861 location_t loc;
18873 {
18875 {
18879 }
18908 else
18921 {
18926 }
18930 {
18932 tree init;
18938 {
18941 {
18945 {
18950 }
18952 }
18953 else
18954 {
18955 /* This is a non-dependent using-decl, and we'll have
18956 used the names it found during template parsing. We do
18957 not want to do the lookup again, because we might not
18958 find the things we found then. */
18961 /* We still need to push the bindings so that we can look up
18962 this name later. */
18965 }
18966 }
18969 {
18970 /* We're in tsubst_lambda_expr, we've already inserted a new
18971 capture proxy, so look it up and register it. */
18972 tree inst;
18974 {
18978 }
18980 {
18981 inst = (retrieve_local_specialization
18985 }
18986 else
18991 }
18998 /* Don't copy the old closure; we'll create a new one in
18999 tsubst_lambda_expr. */
19001 else
19002 {
19006 {
19007 /* By marking the declaration as instantiated, we avoid
19008 trying to instantiate it. Since instantiate_decl can't
19009 handle local variables, and since we've already done
19010 all that needs to be done, that's the right thing to
19011 do. */
19016 /* Anonymous aggregates are a special case. */
19019 {
19022 {
19026 }
19028 }
19033 {
19041 }
19042 else
19043 {
19065 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
19071 /* In a non-template function, VLA type declarations are
19072 handled in grokdeclarator; for templates, handle them
19073 now. */
19077 {
19081 asmspec_tree
19085 }
19091 }
19092 }
19093 }
19096 }
19106 {
19110 }
19115 {
19116 /* Construct another range_for, if this is not a final
19117 substitution (for inside a generic lambda of a
19118 template). Otherwise convert to a regular for. */
19120 stmt = (processing_template_decl
19137 {
19144 }
19145 else
19146 {
19153 }
19159 }
19166 {
19170 }
19176 {
19180 }
19192 {
19198 }
19201 {
19202 /* We're partially instantiating a generic lambda, but the condition
19203 of the constexpr if is still dependent. Don't substitute into the
19204 branches now, just remember the template arguments. */
19212 }
19216 {
19221 }
19222 else
19223 {
19231 }
19237 {
19247 }
19255 else
19263 else
19284 {
19290 {
19295 }
19296 }
19300 {
19302 tree label;
19309 }
19315 /* Computed goto's must be tsubst'd into. On the other hand,
19316 non-computed gotos must not be; the identifier in question
19317 will have no binding. */
19319 else
19325 {
19342 }
19347 {
19352 }
19353 else
19354 {
19359 else
19366 else
19372 else
19374 }
19378 {
19382 {
19384 /* Prevent instantiate_decl from trying to instantiate
19385 this variable. We've already done all that needs to be
19386 done. */
19389 }
19394 }
19400 {
19401 /* Local classes are not independent templates; they are
19402 instantiated along with their containing function. And this
19403 way we don't have to deal with pushing out of one local class
19404 to instantiate a member of another local class. */
19405 /* Closures are handled by the LAMBDA_EXPR. */
19409 {
19410 /* This is a partial instantiation, try again when full. */
19413 }
19427 }
19431 {
19432 tree condition;
19443 }
19450 in_decl);
19472 {
19479 }
19495 {
19509 in_decl);
19511 {
19518 }
19529 any_range_for
19536 {
19545 }
19546 else
19551 else
19558 else
19559 {
19567 }
19570 t));
19572 }
19578 /* FALLTHRU */
19588 in_decl);
19590 {
19595 }
19596 else
19597 {
19601 }
19606 {
19608 "%<#pragma omp critical%> with %<hint%> clause requires "
19611 }
19622 {
19625 {
19630 }
19631 else
19632 {
19636 }
19638 }
19639 else
19641 OMP_CLAUSE_DEPEND_INVALID,
19650 ? C_ORT_ACC
19669 {
19672 /* For combined target teams, ensure the num_teams and
19673 thread_limit clause expressions are evaluated on the host,
19674 before entering the target construct. */
19683 {
19686 tf_none);
19693 OMP_CLAUSE_FIRSTPRIVATE);
19697 }
19698 }
19735 {
19739 }
19740 else
19751 /* FALLTHRU */
19769 {
19775 {
19778 }
19780 {
19784 {
19787 }
19792 }
19793 else
19794 {
19797 }
19802 }
19803 else
19804 {
19811 {
19814 }
19817 {
19822 {
19825 }
19827 {
19831 {
19834 }
19839 }
19840 else
19841 {
19844 }
19848 }
19849 else
19850 {
19854 }
19858 }
19862 {
19868 {
19872 {
19877 }
19881 }
19882 else
19883 {
19888 }
19889 }
19893 {
19897 }
19910 /* If the first operand was a statement, we're done with it. */
19915 complain));
19931 }
19934 out:
19937 #undef RECUR
19938 #undef RETURN
19939 }
19941 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
19942 function. For description of the body see comment above
19943 cp_parser_omp_declare_reduction_exprs. */
19945 static void
19947 {
19953 tree_stmt_iterator tsi;
19964 {
19971 /* tsubsting a local var_decl leaves DECL_CONTEXT null, as we
19972 expect to be pushing it. */
19984 }
19986 {
20006 }
20007 }
20009 /* T is a postfix-expression that is not being used in a function
20010 call. Return the substituted version of T. */
20012 static tree
20014 tsubst_flags_t complain,
20015 tree in_decl)
20016 {
20020 else
20024 }
20026 /* Subroutine of tsubst_lambda_expr: add the FIELD/INIT capture pair to the
20027 LAMBDA_EXPR_CAPTURE_LIST passed in LIST. Do deduction for a previously
20028 dependent init-capture. EXPLICIT_P is true if the original list had
20029 explicit captures. */
20031 static void
20033 tsubst_flags_t complain)
20034 {
20036 {
20039 {
20043 }
20050 }
20053 }
20055 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
20056 instantiation context. Instantiating a pack expansion containing a lambda
20057 might result in multiple lambdas all based on the same lambda in the
20058 template. */
20060 tree
20062 {
20077 else
20088 {
20093 else
20105 {
20106 /* For a VLA, simply tsubsting the field type won't work, we need to
20107 go through add_capture again. XXX do we want to do this for all
20108 captures? */
20109 tree name = (get_identifier
20117 }
20124 {
20125 /* Remember these for when we've pushed local_specializations. */
20128 }
20134 {
20143 complain);
20144 }
20145 else
20146 {
20152 }
20153 }
20162 /* If we're pushed into another scope (PR105652), fix it. */
20167 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
20184 {
20187 }
20190 {
20193 }
20197 else
20198 {
20199 /* The body of a lambda-expression is not a subexpression of the
20200 enclosing expression. Parms are to have DECL_CHAIN tsubsted,
20201 which would be skipped if cp_unevaluated_operand. */
20202 cp_evaluated ev;
20204 /* Fix the type of 'this'. */
20208 tree inst = (oldtmpl
20213 {
20216 }
20222 /* Let finish_function set this. */
20228 else
20229 /* Still increment function_depth so that we don't GC in the
20230 middle of an expression. */
20240 /* Now record them for lookup_init_capture_pack. */
20243 {
20247 }
20253 {
20254 /* We might not partially instantiate some parts of the function, so
20255 copy these flags from the original template. */
20261 }
20263 /* [temp.deduct] A lambda-expression appearing in a function type or a
20264 template parameter is not considered part of the immediate context for
20265 the purposes of template argument deduction. */
20270 /* We already have a body block from start_lambda_function, we don't
20271 need another to confuse NRV (91217). */
20282 else
20285 /* The capture list was built up in reverse order; fix that now. */
20292 }
20294 out:
20300 }
20302 /* Subroutine of maybe_fold_fn_template_args. */
20304 static bool
20306 {
20309 {
20315 {
20318 }
20323 {
20327 }
20328 }
20331 }
20333 /* Try to do constant evaluation of any explicit template arguments in FN
20334 before overload resolution, to get any errors only once. Return true iff
20335 we didn't have any problems folding. */
20337 static bool
20339 {
20357 }
20359 /* Helper function for tsubst_copy_and_build CALL_EXPR and ARRAY_REF
20360 handling. */
20362 static void
20365 {
20368 {
20374 else
20375 {
20376 /* Expand the pack expansion and push each entry onto CALL_ARGS. */
20379 {
20384 {
20389 }
20390 }
20391 else
20392 /* A partial substitution. Add one entry. */
20394 }
20395 }
20396 }
20398 /* Like tsubst but deals with expressions and performs semantic
20399 analysis. */
20401 tree
20403 tree args,
20404 tsubst_flags_t complain,
20405 tree in_decl)
20406 {
20407 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
20408 #define RECUR(NODE) \
20409 tsubst_copy_and_build (NODE, args, complain, in_decl)
20412 location_t save_loc;
20421 /* N3276 decltype magic only applies to calls at the top level or on the
20422 right side of a comma. */
20427 {
20430 /* Fall through. */
20432 {
20433 tree decl;
20434 cp_id_kind idk;
20438 {
20441 }
20443 /* Look up the name. */
20446 /* By convention, expressions use ERROR_MARK_NODE to indicate
20447 failure, not NULL_TREE. */
20461 input_location);
20465 {
20469 }
20471 }
20474 {
20475 tree object;
20486 {
20491 }
20494 {
20501 /* If we built a function concept check, return the underlying
20502 template-id. So we can evaluate it as a function call. */
20507 }
20510 {
20512 complain);
20516 }
20519 {
20522 }
20523 else
20533 {
20534 /* C++20 P0846: we can encounter an IDENTIFIER_NODE here when
20535 name lookup found nothing when parsing the template name. */
20538 }
20539 else
20541 }
20544 {
20548 {
20549 /* A type conversion to reference type will be enclosed in
20550 such an indirect ref, but the substitution of the cast
20551 will have also added such an indirect ref. */
20553 }
20554 else
20563 }
20566 {
20570 }
20573 {
20577 {
20582 }
20584 /* We'll pass this to convert_nontype_argument again, we don't need
20585 to actually perform any conversion here. */
20593 flags));
20594 }
20597 {
20603 }
20610 {
20611 tree type;
20625 {
20645 }
20648 }
20651 {
20655 }
20680 {
20687 }
20690 /* convert_like should have created an IMPLICIT_CONV_EXPR. */
20701 else
20703 in_decl);
20738 {
20739 /* If either OP0 or OP1 was value- or type-dependent, suppress
20740 warnings that depend on the range of the types involved. */
20754 tree r = build_x_binary_op
20756 op0,
20758 ? ERROR_MARK
20760 op1,
20762 ? ERROR_MARK
20771 }
20774 {
20782 }
20798 {
20800 releasing_vec index_exp_list;
20802 index_exp_list);
20804 tree r;
20810 else
20815 }
20824 /* Fall through */
20827 {
20828 tree r;
20836 {
20837 /* When there are no ARGS, we are trying to evaluate a
20838 non-dependent expression from the parser. Trying to do
20839 the substitutions may not work. */
20842 }
20843 else
20844 {
20849 else
20853 }
20858 else
20863 {
20865 {
20867 {
20871 }
20872 else
20876 }
20878 }
20880 }
20883 {
20891 }
20905 {
20910 tree r = build_x_modify_expr
20914 /* TREE_NO_WARNING must be set if either the expression was
20915 parenthesized or it uses an operator such as >>= rather
20916 than plain assignment. In the former case, it was already
20917 set and must be copied. In the latter case,
20918 build_x_modify_expr sets it and it must not be reset
20919 here. */
20924 }
20929 /* Remember that there was a reference to this entity. */
20936 {
20941 tree ret;
20948 else
20949 {
20953 }
20955 /* If there was an initializer in the original tree, but it
20956 instantiated to an empty list, then we should pass a
20957 non-NULL empty vector to tell build_new that it was an
20958 empty initializer() rather than no initializer. This can
20959 only happen when the initializer is a pack expansion whose
20960 parameter packs are of length zero. */
20965 else
20966 {
20970 else
20971 {
20974 }
20975 }
20977 /* Avoid passing an enclosing decl to valid_array_size_p. */
20984 complain);
20992 }
20995 {
21001 complain));
21002 }
21005 {
21009 op0,
21013 }
21016 {
21017 tree function;
21021 tree ret;
21024 /* Internal function with no arguments. */
21028 /* When we parsed the expression, we determined whether or
21029 not Koenig lookup should be performed. */
21032 {
21035 }
21037 {
21042 }
21047 {
21048 /* Do nothing; calling tsubst_copy_and_build on an identifier
21049 would incorrectly perform unqualified lookup again.
21051 Note that we can also have an IDENTIFIER_NODE if the earlier
21052 unqualified lookup found a dependent local extern declaration
21053 (as per finish_call_expr); in that case koenig_p will be false
21054 and we do want to do the lookup again to find the substituted
21055 declaration. */
21059 /* Use tsubst_copy to substitute through the template arguments
21060 of the template-id without performing unqualified lookup of
21061 the template name. */
21063 }
21064 else
21065 {
21067 {
21073 }
21074 else
21079 /* Avoid error about taking the address of a constructor. */
21084 /* When KOENIG_P, we don't want to mark_used the callee before
21085 augmenting the overload set via ADL, so during this initial
21086 substitution we disable mark_used by setting tf_conv (68942). */
21092 }
21095 releasing_vec call_args;
21097 call_args);
21099 /* Stripped-down processing for a call in a thunk. Specifically, in
21100 the thunk template for a generic lambda. */
21102 {
21103 /* Now that we've expanded any packs, the number of call args
21104 might be different. */
21108 {
21115 }
21116 /* We aren't going to do normal overload resolution, so force the
21117 template-id to resolve. */
21120 {
21121 /* In a thunk, pass through args directly, without any
21122 conversions. */
21127 }
21129 {
21130 /* If there are no other args, just push 'this'. */
21133 else
21134 {
21135 /* Otherwise, shift the other args over to make room. */
21141 }
21142 }
21145 /* The thunk location is not interesting. */
21152 }
21154 /* We do not perform argument-dependent lookup if normal
21155 lookup finds a non-function, in accordance with the
21156 resolution of DR 218. */
21159 /* If lookup found a member function, the Koenig lookup is
21160 not appropriate, even if an unqualified-name was used
21161 to denote the function. */
21164 /* C++20 P0846: Lookup found nothing. */
21167 /* Only do this when substitution turns a dependent call
21168 into a non-dependent call. */
21180 {
21185 {
21186 /* For backwards compatibility and good diagnostics, try
21187 the unqualified lookup again if we aren't in SFINAE
21188 context. */
21195 {
21198 "and no declarations were found by "
21199 "argument-dependent lookup at the point "
21204 /* In a lambda fn, we have to be careful to not
21205 introduce new this captures. Legacy code can't
21206 be using lambdas anyway, so it's ok to be
21207 stricter. Be strict with C++20 template-id ADL too.
21208 And be strict if we're already failing anyway. */
21214 else
21218 {
21229 {
21232 "declarations in dependent base %qT are "
21238 else
21242 }
21243 else
21245 "%qD declared here, later in the "
21249 }
21252 }
21253 }
21255 {
21259 }
21260 }
21262 /* Remember that there was a reference to this entity. */
21271 /* Put back tf_decltype for the actual call. */
21276 {
21280 {
21282 "wrong number of arguments to "
21285 }
21286 else
21294 {
21296 "wrong number of arguments to "
21300 }
21304 complain);
21310 {
21312 complain);
21316 }
21321 {
21323 "wrong number of arguments to "
21326 }
21327 else
21328 {
21333 {
21336 }
21339 }
21343 /* Unsupported internal function with arguments. */
21345 }
21350 complain);
21352 {
21367 complain);
21368 else
21369 ret = (build_new_method_call
21374 complain));
21375 }
21377 {
21378 /* FUNCTION is a template-id referring to a concept definition. */
21383 /* Calls to standard and variable concepts should have been
21384 previously diagnosed. */
21387 /* Ensure the result is wrapped as a call expression. */
21389 }
21390 else
21393 koenig_p,
21394 complain);
21397 {
21403 {
21407 }
21409 /* This also suppresses -Wredundant-move. */
21411 }
21414 }
21417 {
21424 {
21426 {
21431 }
21432 else
21433 {
21438 }
21440 }
21441 else
21442 {
21445 }
21450 }
21453 {
21458 input_location));
21459 }
21465 {
21466 tree object;
21467 tree object_type;
21468 tree member;
21469 tree r;
21473 /* Remember that there was a reference to this entity. */
21484 else
21491 {
21494 }
21496 {
21498 complain);
21502 }
21506 {
21508 {
21513 {
21516 }
21518 {
21523 }
21524 }
21525 }
21528 {
21529 /* Lookup the template functions now that we know what the
21530 scope is. */
21537 {
21540 args);
21541 member = (adjust_result_of_qualified_name_lookup
21543 object_type));
21544 }
21545 else
21546 {
21548 input_location);
21550 }
21551 }
21555 {
21557 {
21561 else
21564 }
21566 }
21570 complain);
21574 }
21581 {
21588 tree r;
21597 /* We do not want to process the index of aggregate
21598 initializers as they are identifier nodes which will be
21599 looked up by digest_init. */
21603 {
21606 }
21611 {
21613 /* An identifier index is looked up in the type
21614 being initialized, not the current scope. */
21619 {
21620 /* Substitute into the pack expansion. */
21622 in_decl);
21626 ;
21628 /* Just move the argument into place. */
21630 else
21631 {
21632 /* Update the length of the final CONSTRUCTOR
21633 arguments vector, and note that we will need to
21634 copy.*/
21637 }
21638 }
21639 else
21641 }
21644 {
21649 {
21651 {
21656 }
21657 else
21659 }
21660 }
21668 {
21673 }
21677 }
21680 {
21683 {
21686 }
21687 else
21688 {
21691 }
21692 }
21697 /* Fall through */
21700 {
21702 /* ??? We're doing a subset of finish_id_expression here. */
21704 /* Replace an evaluated use of the thread_local variable with
21705 a call to its wrapper. */
21711 /* If the original type was a reference, we'll be wrapped in
21712 the appropriate INDIRECT_REF. */
21715 }
21718 {
21722 }
21725 {
21726 tree object_ptr
21732 }
21739 {
21746 }
21749 {
21758 /* If the resulting list of expression statement is empty,
21759 fold it further into void_node. */
21764 }
21767 {
21769 {
21770 /* We don't have a full set of template arguments yet; don't touch
21771 the lambda at all. */
21774 }
21778 }
21786 else
21787 /* Recreate the PAREN_EXPR from __builtin_assoc_barrier. */
21788 {
21792 }
21795 {
21800 complain));
21801 }
21804 {
21807 }
21810 /* No need to substitute further, a RANGE_EXPR will always be built
21811 with constant operands. */
21816 {
21820 /* We need to do this here as well as in tsubst_copy so we get the
21821 other tsubst_copy_and_build semantics for a PARM_DECL operand. */
21826 /* force_paren_expr can also create a VIEW_CONVERT_EXPR. */
21829 /* Otherwise, we're dealing with a wrapper to make a C++20 template
21830 parameter object const. */
21833 {
21834 /* The template argument is not const, presumably because
21835 it is still dependent, and so not the const template parm
21836 object. */
21840 {
21841 /* Don't add a wrapper to these. */
21844 }
21845 else
21846 /* Do add a wrapper otherwise (in particular, if op is
21847 another TEMPLATE_PARM_INDEX). */
21849 }
21851 }
21854 /* Handle Objective-C++ constructs, if appropriate. */
21855 {
21856 tree subst
21860 }
21862 }
21864 #undef RECUR
21865 #undef RETURN
21866 out:
21869 }
21871 /* Verify that the instantiated ARGS are valid. For type arguments,
21872 make sure that the type's linkage is ok. For non-type arguments,
21873 make sure they are constants if they are integral or enumerations.
21874 Emit an error under control of COMPLAIN, and return TRUE on error. */
21876 static bool
21878 {
21882 {
21892 }
21894 {
21895 /* [basic.link]: A name with no linkage (notably, the name
21896 of a class or enumeration declared in a local scope)
21897 shall not be used to declare an entity with linkage.
21898 This implies that names with no linkage cannot be used as
21899 template arguments
21901 DR 757 relaxes this restriction for C++0x. */
21906 {
21907 /* DR 488 makes use of a type with no linkage cause
21908 type deduction to fail. */
21910 {
21913 else
21916 }
21918 }
21919 /* In order to avoid all sorts of complications, we do not
21920 allow variably-modified types as template arguments. */
21922 {
21926 }
21927 }
21928 /* Class template and alias template arguments should be OK. */
21930 ;
21931 /* A non-type argument of integral or enumerated type must be a
21932 constant. */
21937 {
21941 }
21943 }
21945 static bool
21947 {
21952 {
21955 }
21959 }
21961 /* Call mark_used on each entity within the non-type template arguments in
21962 ARGS for an instantiation of TMPL, to ensure that each such entity is
21963 considered odr-used (and therefore marked for instantiation) regardless of
21964 whether the specialization was first formed in a template context (which
21965 inhibits mark_used).
21967 This function assumes push_to_top_level has been called beforehand. */
21969 static void
21971 {
21972 /* It suffices to do this only when instantiating a primary template. */
21976 /* We already marked outer arguments when specializing the context. */
21980 {
21981 /* A (pointer/reference to) function or variable NTTP argument. */
21984 {
21990 {
21991 /* Pass tf_none to avoid duplicate diagnostics: if this call
21992 fails then an earlier call to mark_used for this argument
21993 must have also failed and emitted a diagnostic. */
21996 }
21997 }
21998 /* A class NTTP argument. */
22001 {
22004 {
22007 }
22009 };
22012 }
22013 }
22014 }
22016 /* We're out of SFINAE context now, so generate diagnostics for the access
22017 errors we saw earlier when instantiating D from TMPL and ARGS. */
22019 static void
22021 {
22033 }
22035 /* Instantiate the indicated variable, function, or alias template TMPL with
22036 the template arguments in TARG_PTR. */
22038 tree
22040 {
22044 tree fndecl;
22045 tree gen_tmpl;
22051 /* The other flags are not relevant anymore here, especially tf_partial
22052 shouldn't be set. For instance, we may be called while doing a partial
22053 substitution of a template variable, but the type of the variable
22054 template may be auto, in which case we will call do_auto_deduction
22055 in mark_used (which clears tf_partial) and the auto must be properly
22056 reduced at that time for the deduction to work. */
22064 /* If this function is a clone, handle it specially. */
22066 {
22067 tree spec;
22068 tree clone;
22070 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
22071 DECL_CLONED_FUNCTION. */
22077 /* Look for the clone. */
22081 /* We should always have found the clone by now. */
22084 }
22089 /* Check to see if we already have this specialization. */
22093 /* targ_ptr only has the innermost template args, so add the outer ones
22094 from tmpl, which could be either a partial instantiation or gen_tmpl (in
22095 the case of a non-dependent call within a template definition). */
22096 targ_ptr = (add_outermost_template_args
22098 targ_ptr));
22104 || ((fndecl
22110 {
22112 {
22116 }
22118 }
22121 complain))
22124 /* We are building a FUNCTION_DECL, during which the access of its
22125 parameters and return types have to be checked. However this
22126 FUNCTION_DECL which is the desired context for access checking
22127 is not built yet. We solve this chicken-and-egg problem by
22128 deferring all checks until we have the FUNCTION_DECL. */
22131 /* Instantiation of the function happens in the context of the function
22132 template, not the context of the overload resolution we're doing. */
22134 /* If there are dependent arguments, e.g. because we're doing partial
22135 ordering, make sure processing_template_decl stays set. */
22139 {
22140 tree ctx;
22142 /* If the context of the partially instantiated template is
22143 already non-dependent, then we might as well use it. */
22145 else
22149 }
22156 {
22157 /* We need to determine if we're using a partial or explicit
22158 specialization now, because the type of the variable could be
22159 different. */
22165 {
22171 }
22172 }
22174 /* Substitute template parameters to obtain the specialization. */
22182 {
22185 }
22187 /* The DECL_TI_TEMPLATE should always be the immediate parent
22188 template, not the most general template. */
22192 /* Now that we we've formed this variable template specialization,
22193 remember the result of most_specialized_partial_spec for it. */
22202 /* Now we know the specialization, compute access previously
22203 deferred. Do no access control for inheriting constructors,
22204 as we already checked access for the inherited constructor. */
22207 {
22212 }
22215 /* If we've just instantiated the main entry point for a function,
22216 instantiate all the alternate entry points as well. We do this
22217 by cloning the instantiation of the main entry point, not by
22218 instantiating the template clones. */
22224 {
22226 {
22227 /* Remember to reinstantiate when we're out of SFINAE so the user
22228 can see the errors. */
22230 }
22232 }
22235 }
22237 /* Instantiate the alias template TMPL with ARGS. Also push a template
22238 instantiation level, which instantiate_template doesn't do because
22239 functions and variables have sufficient context established by the
22240 callers. */
22242 static tree
22244 {
22253 /* FIXME check for satisfaction in check_instantiated_args. */
22255 {
22257 {
22258 auto_diagnostic_group d;
22261 }
22263 }
22271 {
22272 /* An alias template specialization can be dependent
22273 even if its underlying type is not. */
22276 /* Sometimes a dependent alias spec is equivalent to its expansion,
22277 sometimes not. So always use structural_comptypes. */
22279 }
22282 }
22284 /* PARM is a template parameter pack for FN. Returns true iff
22285 PARM is used in a deducible way in the argument list of FN. */
22287 static bool
22289 {
22292 {
22294 tree packs;
22300 {
22301 /* The template parameter pack is used in a function parameter
22302 pack. If this is the end of the parameter list, the
22303 template parameter pack is deducible. */
22306 else
22307 /* Otherwise, not. Well, it could be deduced from
22308 a non-pack parameter, but doing so would end up with
22309 a deduction mismatch, so don't bother. */
22311 }
22312 }
22313 /* The template parameter pack isn't used in any function parameter
22314 packs, but it might be used deeper, e.g. tuple<Args...>. */
22316 }
22318 /* Subroutine of fn_type_unification: check non-dependent parms for
22319 convertibility. */
22321 static int
22325 {
22326 /* Non-constructor methods need to leave a conversion for 'this', which
22327 isn't included in nargs here. */
22333 {
22339 /* For a function parameter pack that occurs at the end of the
22340 parameter-declaration-list, the type A of each remaining
22341 argument of the call is compared with the type P of the
22342 declarator-id of the function parameter pack. */
22348 /* For a function parameter pack that does not occur at the
22349 end of the parameter-declaration-list, the type of the
22350 parameter pack is a non-deduced context. */
22354 {
22362 }
22365 }
22368 }
22370 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
22371 NARGS elements of the arguments that are being used when calling
22372 it. TARGS is a vector into which the deduced template arguments
22373 are placed.
22375 Returns either a FUNCTION_DECL for the matching specialization of FN or
22376 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
22377 true, diagnostics will be printed to explain why it failed.
22379 If FN is a conversion operator, or we are trying to produce a specific
22380 specialization, RETURN_TYPE is the return type desired.
22382 The EXPLICIT_TARGS are explicit template arguments provided via a
22383 template-id.
22385 The parameter STRICT is one of:
22387 DEDUCE_CALL:
22388 We are deducing arguments for a function call, as in
22389 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
22390 deducing arguments for a call to the result of a conversion
22391 function template, as in [over.call.object].
22393 DEDUCE_CONV:
22394 We are deducing arguments for a conversion function, as in
22395 [temp.deduct.conv].
22397 DEDUCE_EXACT:
22398 We are deducing arguments when doing an explicit instantiation
22399 as in [temp.explicit], when determining an explicit specialization
22400 as in [temp.expl.spec], or when taking the address of a function
22401 template, as in [temp.deduct.funcaddr]. */
22403 tree
22405 tree explicit_targs,
22406 tree targs,
22409 tree return_type,
22410 unification_kind_t strict,
22415 {
22416 tree parms;
22417 tree fntype;
22422 /* type_unification_real will pass back any access checks from default
22423 template argument substitution. */
22425 /* We don't have all the template args yet. */
22438 full_targs = (add_outermost_template_args
22440 targs));
22445 /* In C++0x, it's possible to have a function template whose type depends
22446 on itself recursively. This is most obvious with decltype, but can also
22447 occur with enumeration scope (c++/48969). So we need to catch infinite
22448 recursion and reject the substitution at deduction time; this function
22449 will return error_mark_node for any repeated substitution.
22451 This also catches excessive recursion such as when f<N> depends on
22452 f<N-1> across all integers, and returns error_mark_node for all the
22453 substitutions back up to the initial one.
22455 This is, of course, not reentrant. */
22464 {
22465 /* [temp.deduct]
22467 The specified template arguments must match the template
22468 parameters in kind (i.e., type, nontype, template), and there
22469 must not be more arguments than there are parameters;
22470 otherwise type deduction fails.
22472 Nontype arguments must match the types of the corresponding
22473 nontype template parameters, or must be convertible to the
22474 types of the corresponding nontype parameters as specified in
22475 _temp.arg.nontype_, otherwise type deduction fails.
22477 All references in the function type of the function template
22478 to the corresponding template parameters are replaced by the
22479 specified template argument values. If a substitution in a
22480 template parameter or in the function type of the function
22481 template results in an invalid type, type deduction fails. */
22492 explicit_targs);
22494 /* Adjust any explicit template arguments before entering the
22495 substitution context. */
22496 explicit_targs
22503 /* Substitute the explicit args into the function type. This is
22504 necessary so that, for instance, explicitly declared function
22505 arguments can match null pointed constants. If we were given
22506 an incomplete set of explicit args, we must not do semantic
22507 processing during substitution as we could create partial
22508 instantiations. */
22510 {
22515 /* Dig out the actual parm. */
22518 {
22521 }
22523 {
22526 }
22529 /* No explicit argument for this template parameter. */
22532 {
22533 /* Mark the argument pack as "incomplete". We could
22534 still deduce more arguments during unification.
22535 We remove this mark in type_unification_real. */
22540 /* We have some incomplete argument packs. */
22542 }
22543 }
22546 {
22548 {
22551 }
22554 /* Ignore any access checks; we'll see them again in
22555 instantiate_template and they might have the wrong
22556 access path at this point. */
22567 }
22569 /* Place the explicitly specified arguments in TARGS. */
22575 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
22577 }
22580 {
22586 }
22591 /* Never do unification on the 'this' parameter. */
22595 {
22596 /* We're deducing for a call to the result of a template conversion
22597 function. The parms we really want are in return_type. */
22601 }
22603 {
22605 }
22607 /* We allow incomplete unification without an error message here
22608 because the standard doesn't seem to explicitly prohibit it. Our
22609 callers must be ready to deal with unification failures in any
22610 event. */
22612 /* If we aren't explaining yet, push tinst context so we can see where
22613 any errors (e.g. from class instantiations triggered by instantiation
22614 of default template arguments) come from. If we are explaining, this
22615 context is redundant. */
22617 {
22620 }
22630 /* Now that we have bindings for all of the template arguments,
22631 ensure that the arguments deduced for the template template
22632 parameters have compatible template parameter lists. We cannot
22633 check this property before we have deduced all template
22634 arguments, because the template parameter types of a template
22635 template parameter might depend on prior template parameters
22636 deduced after the template template parameter. The following
22637 ill-formed example illustrates this issue:
22639 template<typename T, template<T> class C> void f(C<5>, T);
22641 template<int N> struct X {};
22643 void g() {
22644 f(X<5>(), 5l); // error: template argument deduction fails
22645 }
22647 The template parameter list of 'C' depends on the template type
22648 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
22649 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
22650 time that we deduce 'C'. */
22653 {
22656 }
22658 deduced:
22660 /* CWG2369: Check satisfaction before non-deducible conversions. */
22662 {
22666 }
22668 /* DR 1391: All parameters have args, now check non-dependent parms for
22669 convertibility. We don't do this if all args were explicitly specified,
22670 as the standard says that we substitute explicit args immediately. */
22676 /* All is well so far. Now, check:
22678 [temp.deduct]
22680 When all template arguments have been deduced, all uses of
22681 template parameters in nondeduced contexts are replaced with
22682 the corresponding deduced argument values. If the
22683 substitution results in an invalid type, as described above,
22684 type deduction fails. */
22686 {
22689 }
22691 /* Also collect access checks from the instantiation. */
22704 /* Now perform any access checks encountered during substitution. */
22711 /* If we're looking for an exact match, check that what we got
22712 is indeed an exact match. It might not be if some template
22713 parameters are used in non-deduced contexts. But don't check
22714 for an exact match if we have dependent template arguments;
22715 in that case we're doing partial ordering, and we already know
22716 that we have two candidates that will provide the actual type. */
22718 {
22722 tree sarg
22728 {
22732 }
22734 /* add_candidates uses DEDUCE_EXACT for x.operator foo(), but args
22735 doesn't contain the trailing void, and conv fns are always (). */
22737 {
22741 }
22742 }
22744 /* After doing deduction with the inherited constructor, actually return an
22745 instantiation of the inheriting constructor. */
22751 fail:
22754 {
22756 /* Reset once we're all the way out. */
22758 }
22761 }
22763 /* Returns true iff PARM is a forwarding reference in the context of
22764 template argument deduction for TMPL. */
22766 static bool
22768 {
22769 /* [temp.deduct.call], "A forwarding reference is an rvalue reference to a
22770 cv-unqualified template parameter ..." */
22775 {
22777 /* [temp.deduct.call], "... that does not represent a template parameter
22778 of a class template (during class template argument deduction)." */
22782 {
22783 /* Since the template parameters of a synthesized guide consist of
22784 the template parameters of the class template followed by those of
22785 the constructor (if any), we can tell if PARM represents a template
22786 parameter of the class template by comparing its index with the
22787 arity of the class template. */
22792 }
22794 }
22796 }
22798 /* Adjust types before performing type deduction, as described in
22799 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
22800 sections are symmetric. PARM is the type of a function parameter
22801 or the return type of the conversion function. ARG is the type of
22802 the argument passed to the call, or the type of the value
22803 initialized with the result of the conversion function.
22804 ARG_EXPR is the original argument expression, which may be null. */
22806 static int
22808 unification_kind_t strict,
22811 tree arg_expr)
22812 {
22816 {
22821 /* [temp.deduct.conv] First remove a reference type on parm.
22822 DRs 322 & 976 affected this. */
22826 /* Swap PARM and ARG throughout the remainder of this
22827 function; the handling is precisely symmetric since PARM
22828 will initialize ARG rather than vice versa. */
22834 /* Core issue #873: Do the DR606 thing (see below) for these cases,
22835 too, but here handle it by stripping the reference from PARM
22836 rather than by adding it to ARG. */
22841 /* Nothing else to do in this case. */
22846 }
22849 {
22850 /* [temp.deduct.call]
22852 If P is not a reference type:
22854 --If A is an array type, the pointer type produced by the
22855 array-to-pointer standard conversion (_conv.array_) is
22856 used in place of A for type deduction; otherwise,
22858 --If A is a function type, the pointer type produced by
22859 the function-to-pointer standard conversion
22860 (_conv.func_) is used in place of A for type deduction;
22861 otherwise,
22863 --If A is a cv-qualified type, the top level
22864 cv-qualifiers of A's type are ignored for type
22865 deduction. */
22870 else
22872 }
22874 /* [temp.deduct.call], "If P is a forwarding reference and the argument is
22875 an lvalue, the type 'lvalue reference to A' is used in place of A for
22876 type deduction." */
22879 /* try_one_overload doesn't provide an arg_expr, but
22880 functions are always lvalues. */
22884 /* [temp.deduct.call]
22886 If P is a cv-qualified type, the top level cv-qualifiers
22887 of P's type are ignored for type deduction. If P is a
22888 reference type, the type referred to by P is used for
22889 type deduction. */
22892 {
22895 }
22898 }
22900 /* Subroutine of fn_type_unification. PARM is a function parameter of a
22901 template which doesn't contain any deducible template parameters; check if
22902 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
22903 unify_one_argument. */
22905 static int
22909 {
22910 tree type;
22914 else
22922 {
22925 }
22927 {
22931 /* Avoid recalculating this in add_function_candidate. */
22932 ok = (*conv_p
22934 else
22938 }
22942 else
22944 }
22948 /* Returns true iff the expression EXPR is one from which a template
22949 argument can be deduced. In other words, if it's an undecorated
22950 use of a template non-type parameter. */
22952 static bool
22954 {
22955 /* Strip implicit conversions and implicit INDIRECT_REFs. */
22961 }
22963 /* Returns true iff the array domain DOMAIN uses a template parameter in a
22964 deducible way; that is, if it has a max value of <PARM> - 1. */
22966 static bool
22968 {
22977 }
22979 /* Returns true iff the template arguments ARGS use a template parameter
22980 in a deducible way. */
22982 static bool
22984 {
22986 {
22990 else
22991 {
22998 else
23000 }
23003 }
23005 }
23007 /* Returns true iff TYPE contains any deducible references to template
23008 parameters, as per 14.8.2.5. */
23010 static bool
23012 {
23016 /* T
23017 cv-list T
23018 TT<T>
23019 TT<i>
23020 TT<> */
23025 /* T*
23026 T&
23027 T&& */
23031 /* T[integer-constant ]
23032 type [i] */
23037 /* T type ::*
23038 type T::*
23039 T T::*
23040 T (type ::*)()
23041 type (T::*)()
23042 type (type ::*)(T)
23043 type (T::*)(T)
23044 T (type ::*)(T)
23045 T (T::*)()
23046 T (T::*)(T) */
23049 || (uses_deducible_template_parms
23052 /* template-name <T> (where template-name refers to a class template)
23053 template-name <i> (where template-name refers to a class template) */
23060 /* type (T)
23061 T()
23062 T(T) */
23064 {
23078 }
23081 }
23083 /* Subroutine of type_unification_real and unify_pack_expansion to
23084 handle unification of a single P/A pair. Parameters are as
23085 for those functions. */
23087 static int
23091 {
23098 /* We can't deduce anything from this, but we might get all the
23099 template args from other function args. */
23102 /* Implicit conversions (Clause 4) will be performed on a function
23103 argument to convert it to the type of the corresponding function
23104 parameter if the parameter type contains no template-parameters that
23105 participate in template argument deduction. */
23108 /* For function parameters with no deducible template parameters,
23109 just return. We'll check non-dependent conversions later. */
23113 {
23115 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
23116 | UNIFY_ALLOW_MORE_CV_QUAL
23130 }
23132 /* We only do these transformations if this is the top-level
23133 parameter_type_list in a call or declaration matching; in other
23134 situations (nested function declarators, template argument lists) we
23135 won't be comparing a type to an expression, and we don't do any type
23136 adjustments. */
23138 {
23140 {
23143 {
23144 /* [temp.deduct.type] A template-argument can be
23145 deduced from a pointer to function or pointer
23146 to member function argument if the set of
23147 overloaded functions does not contain function
23148 templates and at most one of a set of
23149 overloaded functions provides a unique
23150 match. */
23154 /* If a unique match was not found, this is a
23155 non-deduced context, so we still succeed. */
23157 }
23163 }
23167 }
23168 else
23173 /* For deduction from an init-list we need the actual list. */
23177 }
23179 /* for_each_template_parm callback that always returns 0. */
23181 static int
23183 {
23185 }
23187 /* for_each_template_parm any_fn callback to handle deduction of a template
23188 type argument from the type of an array bound. */
23190 static int
23192 {
23200 {
23206 }
23208 /* Keep walking. */
23210 }
23212 /* Try to deduce any not-yet-deduced template type arguments from the type of
23213 an array bound. This is handled separately from unify because 14.8.2.5 says
23214 "The type of a type parameter is only deduced from an array bound if it is
23215 not otherwise deduced." */
23217 static void
23219 {
23224 }
23226 /* Most parms like fn_type_unification.
23228 If SUBR is 1, we're being called recursively (to unify the
23229 arguments of a function or method parameter of a function
23230 template).
23232 CHECKS is a pointer to a vector of access checks encountered while
23233 substituting default template arguments. */
23235 static int
23237 tree full_targs,
23238 tree xparms,
23242 unification_kind_t strict,
23245 {
23250 tree parms;
23261 /* Reset the number of non-defaulted template arguments contained
23262 in TARGS. */
23265 again:
23270 /* Only fn_type_unification cares about terminal void. */
23277 {
23282 /* For a function parameter pack that occurs at the end of the
23283 parameter-declaration-list, the type A of each remaining
23284 argument of the call is compared with the type P of the
23285 declarator-id of the function parameter pack. */
23291 /* For a function parameter pack that does not occur at the
23292 end of the parameter-declaration-list, the type of the
23293 parameter pack is a non-deduced context. */
23300 explain_p))
23302 }
23307 {
23308 /* Unify the remaining arguments with the pack expansion type. */
23309 tree argvec;
23312 /* Allocate a TREE_VEC and copy in all of the arguments */
23317 /* Copy the parameter into parmvec. */
23323 /* Advance to the end of the list of parameters. */
23325 }
23327 /* Fail if we've reached the end of the parm list, and more args
23328 are present, and the parm list isn't variadic. */
23331 /* Fail if parms are left and they don't have default values and
23332 they aren't all deduced as empty packs (c++/57397). This is
23333 consistent with sufficient_parms_p. */
23336 {
23340 do
23341 {
23344 count++;
23346 }
23350 type_pack_p);
23351 }
23354 {
23355 tsubst_flags_t complain = (explain_p
23356 ? tf_warning_or_error
23361 {
23365 /* Clear the "incomplete" flags on all argument packs now so that
23366 substituting them into later default arguments works. */
23368 {
23371 }
23379 {
23384 }
23386 /* If this is an undeduced nontype parameter that depends on
23387 a type parameter, try another pass; its type may have been
23388 deduced from a later argument than the one from which
23389 this parameter can be deduced. */
23394 {
23397 }
23399 /* Core issue #226 (C++0x) [temp.deduct]:
23401 If a template argument has not been deduced, its
23402 default template argument, if any, is used.
23404 When we are in C++98 mode, TREE_PURPOSE will either
23405 be NULL_TREE or ERROR_MARK_NODE, so we do not need
23406 to explicitly check cxx_dialect here. */
23408 /* OK, there is a default argument. Wait until after the
23409 conversion check to do substitution. */
23412 /* If the type parameter is a parameter pack, then it will
23413 be deduced to an empty parameter pack. */
23415 {
23416 tree arg;
23419 {
23422 }
23423 else
23430 }
23433 }
23435 /* During partial ordering, we deduce dependent template args. */
23438 /* Now substitute into the default template arguments. */
23440 {
23445 {
23449 }
23464 {
23465 /* The type of this non-type parameter depends on undeduced
23466 parameters. Don't try to use its default argument yet,
23467 since we might deduce an argument for it on the next pass,
23468 but do check whether the arguments we already have cause
23469 substitution failure, so that that happens before we try
23470 later default arguments (78489). */
23473 NULL_TREE);
23477 else
23479 }
23480 else
23481 {
23482 /* Even if the call is happening in template context, getting
23483 here means it's non-dependent, and a default argument is
23484 considered a separate definition under [temp.decls], so we can
23485 do this substitution without processing_template_decl. This
23486 is important if the default argument contains something that
23487 might be instantiation-dependent like access (87480). */
23491 {
23492 /* First instatiate in template context, in case we still
23493 depend on undeduced template parameters. */
23496 NULL_TREE);
23500 /* We replaced all the tparms, substitute again out of
23501 template context. */
23503 }
23506 NULL_TREE);
23515 }
23524 {
23526 /* The position of the first default template argument,
23527 is also the number of non-defaulted arguments in TARGS.
23528 Record that. */
23531 }
23532 }
23536 }
23542 }
23544 /* Subroutine of type_unification_real. Args are like the variables
23545 at the call site. ARG is an overloaded function (or template-id);
23546 we try deducing template args from each of the overloads, and if
23547 only one succeeds, we go with that. Modifies TARGS and returns
23548 true on success. */
23550 static bool
23552 tree targs,
23553 tree parm,
23554 tree arg,
23555 unification_kind_t strict,
23558 {
23565 {
23568 }
23569 else
23573 /* Handle `&x' where `x' is some static or non-static member
23574 function name. */
23580 /* Strip baselink information. */
23585 {
23586 /* If we got some explicit template args, we need to plug them into
23587 the affected templates before we try to unify, in case the
23588 explicit args will completely resolve the templates in question. */
23595 {
23606 {
23611 {
23612 /* Instantiate the function to deduce its return type. */
23616 }
23625 {
23628 }
23629 }
23632 }
23633 /* If no templates (or more than one) are fully resolved by the
23634 explicit arguments, this template-id is a non-deduced context; it
23635 could still be OK if we deduce all template arguments for the
23636 enclosing call through other arguments. */
23639 }
23641 /* If ARG is, for example, "(0, &f)" then its type will be unknown
23642 -- but the deduction does not succeed because the expression is
23643 not just the function on its own. */
23645 else
23647 {
23652 {
23655 }
23656 }
23658 /* [temp.deduct.type] A template-argument can be deduced from a pointer
23659 to function or pointer to member function argument if the set of
23660 overloaded functions does not contain function templates and at most
23661 one of a set of overloaded functions provides a unique match.
23663 So if we found multiple possibilities, we return success but don't
23664 deduce anything. */
23667 {
23671 {
23676 /* Don't forget explicit template arguments in a pack. */
23680 }
23681 }
23686 }
23688 /* Core DR 115: In contexts where deduction is done and fails, or in
23689 contexts where deduction is not done, if a template argument list is
23690 specified and it, along with any default template arguments, identifies
23691 a single function template specialization, then the template-id is an
23692 lvalue for the function template specialization. */
23694 tree
23696 {
23709 {
23712 }
23714 {
23717 }
23719 {
23722 }
23725 {
23729 /* If we got some explicit template args, we need to plug them into
23730 the affected templates before we try to unify, in case the
23731 explicit args will completely resolve the templates in question. */
23739 {
23750 {
23753 {
23756 }
23759 {
23762 }
23763 }
23764 }
23766 {
23774 {
23775 tree base
23778 }
23782 }
23784 /* There were no good options and at least one bad one, so let the
23785 user know what the problem is. */
23787 }
23789 }
23791 /* As above, but error out if the expression remains overloaded. */
23793 tree
23795 {
23798 {
23802 }
23804 }
23806 /* Subroutine of resolve_overloaded_unification; does deduction for a single
23807 overload. Fills TARGS with any deduced arguments, or error_mark_node if
23808 different overloads deduce different arguments for a given parm.
23809 ADDR_P is true if the expression for which deduction is being
23810 performed was of the form "& fn" rather than simply "fn".
23812 Returns 1 on success. */
23814 static int
23816 tree orig_targs,
23817 tree targs,
23818 tree parm,
23819 tree arg,
23820 unification_kind_t strict,
23824 {
23826 tree tempargs;
23832 /* [temp.deduct.type] A template-argument can be deduced from a pointer
23833 to function or pointer to member function argument if the set of
23834 overloaded functions does not contain function templates and at most
23835 one of a set of overloaded functions provides a unique match.
23837 So if this is a template, just return success. */
23850 /* We don't copy orig_targs for this because if we have already deduced
23851 some template args from previous args, unify would complain when we
23852 try to deduce a template parameter for the same argument, even though
23853 there isn't really a conflict. */
23860 /* First make sure we didn't deduce anything that conflicts with
23861 explicitly specified args. */
23863 {
23870 /* Since we're unifying against ourselves, we will fill in
23871 template args used in the function parm list with our own
23872 template parms. Discard them. */
23875 {
23876 /* Check that the argument at each index of the deduced argument pack
23877 is equivalent to the corresponding explicitly specified argument.
23878 We may have deduced more arguments than were explicitly specified,
23879 and that's OK. */
23881 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
23882 that's wrong if we deduce the same argument pack from multiple
23883 function arguments: it's only incomplete the first time. */
23896 }
23899 }
23902 {
23907 }
23910 }
23912 /* PARM is a template class (perhaps with unbound template
23913 parameters). ARG is a fully instantiated type. If ARG can be
23914 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
23915 TARGS are as for unify. */
23917 static tree
23920 {
23929 /* We need to make a new template argument vector for the call to
23930 unify. If we used TARGS, we'd clutter it up with the result of
23931 the attempted unification, even if this class didn't work out.
23932 We also don't want to commit ourselves to all the unifications
23933 we've already done, since unification is supposed to be done on
23934 an argument-by-argument basis. In other words, consider the
23935 following pathological case:
23937 template <int I, int J, int K>
23938 struct S {};
23940 template <int I, int J>
23941 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
23943 template <int I, int J, int K>
23944 void f(S<I, J, K>, S<I, I, I>);
23946 void g() {
23947 S<0, 0, 0> s0;
23948 S<0, 1, 2> s2;
23950 f(s0, s2);
23951 }
23953 Now, by the time we consider the unification involving `s2', we
23954 already know that we must have `f<0, 0, 0>'. But, even though
23955 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
23956 because there are two ways to unify base classes of S<0, 1, 2>
23957 with S<I, I, I>. If we kept the already deduced knowledge, we
23958 would reject the possibility I=1. */
23966 else
23971 }
23973 /* Given a template type PARM and a class type ARG, find the unique
23974 base type in ARG that is an instance of PARM. We do not examine
23975 ARG itself; only its base-classes. If there is not exactly one
23976 appropriate base class, return NULL_TREE. PARM may be the type of
23977 a partial specialization, as well as a plain template type. Used
23978 by unify. */
23980 static enum template_base_result
23983 {
23985 tree binfo;
23991 {
23992 /* The type could not be completed. */
23995 }
23997 /* Walk in inheritance graph order. The search order is not
23998 important, and this avoids multiple walks of virtual bases. */
24000 {
24005 {
24006 /* If there is more than one satisfactory baseclass, then:
24008 [temp.deduct.call]
24010 If they yield more than one possible deduced A, the type
24011 deduction fails.
24013 applies. */
24015 {
24016 /* [temp.deduct.call]/4.3: If there is a class C that is a
24017 (direct or indirect) base class of D and derived (directly or
24018 indirectly) from a class B and that would be a valid deduced
24019 A, the deduced A cannot be B or pointer to B, respectively. */
24021 /* Ignore r. */
24025 else
24026 {
24029 }
24030 }
24033 }
24034 }
24038 }
24040 /* Returns the level of DECL, which declares a template parameter. */
24042 static int
24044 {
24046 {
24056 }
24058 }
24060 /* Decide whether ARG can be unified with PARM, considering only the
24061 cv-qualifiers of each type, given STRICT as documented for unify.
24062 Returns nonzero iff the unification is OK on that basis. */
24064 static int
24066 {
24072 {
24073 /* Although a CVR qualifier is ignored when being applied to a
24074 substituted template parameter ([8.3.2]/1 for example), that
24075 does not allow us to unify "const T" with "int&" because both
24076 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
24077 It is ok when we're allowing additional CV qualifiers
24078 at the outer level [14.8.2.1]/3,1st bullet. */
24087 }
24098 }
24100 /* Determines the LEVEL and INDEX for the template parameter PARM. */
24101 void
24103 {
24107 {
24110 }
24111 else
24112 {
24115 }
24116 }
24118 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
24119 do { \
24120 if (unify (TP, TA, P, A, S, EP)) \
24121 return 1; \
24122 } while (0)
24124 /* Unifies the remaining arguments in PACKED_ARGS with the pack
24125 expansion at the end of PACKED_PARMS. Returns 0 if the type
24126 deduction succeeds, 1 otherwise. STRICT is the same as in
24127 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
24128 function call argument list. We'll need to adjust the arguments to make them
24129 types. SUBR tells us if this is from a recursive call to
24130 type_unification_real, or for comparing two template argument
24131 lists. */
24133 static int
24137 {
24138 tree parm
24144 /* Add in any args remembered from an earlier partial instantiation. */
24152 /* Determine the parameter packs we will be deducing from the
24153 pattern, and record their current deductions. */
24156 {
24160 /* Only template parameter packs can be deduced, not e.g. function
24161 parameter packs or __bases or __integer_pack. */
24165 /* Determine the index and level of this parameter pack. */
24170 /* Keep track of the parameter packs and their corresponding
24171 argument packs. */
24174 }
24176 /* Loop through all of the arguments that have not yet been
24177 unified and unify each with the pattern. */
24179 {
24180 tree parm;
24184 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
24185 or the element of its argument pack at the current index if
24186 this argument was explicitly specified. */
24188 {
24197 {
24200 }
24202 }
24204 /* If we had explicit template arguments, substitute them into the
24205 pattern before deduction. */
24207 {
24208 /* Some arguments might still be unspecified or dependent. */
24216 NULL_TREE);
24221 }
24222 else
24225 /* Unify the pattern with the current argument. */
24227 explain_p))
24230 /* For each parameter pack, collect the deduced value. */
24232 {
24238 }
24239 }
24241 /* Verify that the results of unification with the parameter packs
24242 produce results consistent with what we've seen before, and make
24243 the deduced argument packs available. */
24245 {
24252 /* By default keep the original deduced argument pack.
24253 If necessary, more specific code is going to update the
24254 resulting deduced argument later down in this function. */
24258 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
24259 actually deduce anything. */
24267 {
24268 /* If we had fewer function args than explicit template args,
24269 just use the explicits. */
24274 }
24277 {
24278 tree result;
24279 /* Build the deduced *_ARGUMENT_PACK. */
24281 {
24284 }
24285 else
24290 /* Note the deduced argument packs for this parameter
24291 pack. */
24293 }
24297 {
24298 /* We only had the explicitly-provided arguments before, but
24299 now we have a complete set of arguments. */
24305 }
24306 else
24307 {
24311 /* During template argument deduction for the aggregate deduction
24312 candidate, the number of elements in a trailing parameter pack
24313 is only deduced from the number of remaining function
24314 arguments if it is not otherwise deduced. */
24317 /* FIXME This isn't set properly for partial instantiations. */
24323 /* Inconsistent unification of this parameter pack. */
24325 bad_old_arg,
24326 bad_new_arg);
24327 }
24328 }
24331 }
24333 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
24334 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
24335 parameters and return value are as for unify. */
24337 static int
24341 {
24342 tree parm_max;
24343 tree arg_max;
24347 /* Our representation of array types uses "N - 1" as the
24348 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
24349 not an integer constant. We cannot unify arbitrarily
24350 complex expressions, so we eliminate the MINUS_EXPRs
24351 here. */
24355 {
24358 }
24362 {
24363 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
24364 trying to unify the type of a variable with the type
24365 of a template parameter. For example:
24367 template <unsigned int N>
24368 void f (char (&) [N]);
24369 int g();
24370 void h(int i) {
24371 char a[g(i)];
24372 f(a);
24373 }
24375 Here, the type of the ARG will be "int [g(i)]", and
24376 may be a SAVE_EXPR, etc. */
24380 }
24382 /* If only one of the bounds used a MINUS_EXPR, compensate
24383 by adding one to the other bound. */
24386 integer_type_node,
24387 parm_max,
24388 integer_one_node);
24391 integer_type_node,
24392 arg_max,
24393 integer_one_node);
24397 }
24399 /* Returns whether T, a P or A in unify, is a type, template or expression. */
24403 static pa_kind_t
24405 {
24414 else
24416 }
24418 /* Deduce the value of template parameters. TPARMS is the (innermost)
24419 set of template parameters to a template. TARGS is the bindings
24420 for those template parameters, as determined thus far; TARGS may
24421 include template arguments for outer levels of template parameters
24422 as well. PARM is a parameter to a template function, or a
24423 subcomponent of that parameter; ARG is the corresponding argument.
24424 This function attempts to match PARM with ARG in a manner
24425 consistent with the existing assignments in TARGS. If more values
24426 are deduced, then TARGS is updated.
24428 Returns 0 if the type deduction succeeds, 1 otherwise. The
24429 parameter STRICT is a bitwise or of the following flags:
24431 UNIFY_ALLOW_NONE:
24432 Require an exact match between PARM and ARG.
24433 UNIFY_ALLOW_MORE_CV_QUAL:
24434 Allow the deduced ARG to be more cv-qualified (by qualification
24435 conversion) than ARG.
24436 UNIFY_ALLOW_LESS_CV_QUAL:
24437 Allow the deduced ARG to be less cv-qualified than ARG.
24438 UNIFY_ALLOW_DERIVED:
24439 Allow the deduced ARG to be a template base class of ARG,
24440 or a pointer to a template base class of the type pointed to by
24441 ARG.
24442 UNIFY_ALLOW_INTEGER:
24443 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
24444 case for more information.
24445 UNIFY_ALLOW_OUTER_LEVEL:
24446 This is the outermost level of a deduction. Used to determine validity
24447 of qualification conversions. A valid qualification conversion must
24448 have const qualified pointers leading up to the inner type which
24449 requires additional CV quals, except at the outer level, where const
24450 is not required [conv.qual]. It would be normal to set this flag in
24451 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
24452 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
24453 This is the outermost level of a deduction, and PARM can be more CV
24454 qualified at this point.
24455 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
24456 This is the outermost level of a deduction, and PARM can be less CV
24457 qualified at this point. */
24459 static int
24462 {
24464 tree targ;
24465 tree tparm;
24467 tsubst_flags_t complain = (explain_p
24468 ? tf_warning_or_error
24471 /* I don't think this will do the right thing with respect to types.
24472 But the only case I've seen it in so far has been array bounds, where
24473 signedness is the only information lost, and I think that will be
24474 okay. VIEW_CONVERT_EXPR can appear with class NTTP, thanks to
24475 finish_id_expression_1, and are also OK. */
24483 /* We can't deduce anything from this, but we might get all the
24484 template args from other function args. */
24490 /* If PARM uses template parameters, then we can't bail out here,
24491 even if ARG == PARM, since we won't record unifications for the
24492 template parameters. We might need them if we're trying to
24493 figure out which of two things is more specialized. */
24497 /* Handle init lists early, so the rest of the function can assume
24498 we're dealing with a type. */
24500 {
24501 tree elttype;
24506 /* We can only deduce from an initializer list argument if the
24507 parameter is std::initializer_list or an array; otherwise this
24508 is a non-deduced context. */
24513 else
24514 {
24516 /* Deduction is defined in terms of a single type, so just punt
24517 on the (bizarre) std::initializer_list<T...>. */
24520 }
24525 /* If ELTTYPE has no deducible template parms, skip deduction from
24527 else
24529 {
24537 {
24541 /* It should only be possible to get here for a call. */
24543 elt_strict |= maybe_adjust_types_for_deduction
24546 }
24549 explain_p);
24550 }
24554 {
24555 /* Also deduce from the length of the initializer list. */
24562 }
24564 /* If the std::initializer_list<T> deduction worked, replace the
24565 deduced A with std::initializer_list<A>. */
24567 {
24572 }
24574 }
24576 /* If parm and arg aren't the same kind of thing (template, type, or
24577 expression), fail early. */
24581 /* Immediately reject some pairs that won't unify because of
24582 cv-qualification mismatches. */
24585 /* It is the elements of the array which hold the cv quals of an array
24586 type, and the elements might be template type parms. We'll check
24587 when we recurse. */
24589 /* We check the cv-qualifiers when unifying with template type
24590 parameters below. We want to allow ARG `const T' to unify with
24591 PARM `T' for example, when computing which of two templates
24592 is more specialized, for example. */
24601 /* PMFs recurse at the same level, so don't strip this yet. */
24609 {
24613 /* In a type which contains a nested-name-specifier, template
24614 argument values cannot be deduced for template parameters used
24615 within the nested-name-specifier. */
24627 /* The PARM is not one we're trying to unify. Just check
24628 to see if it matches ARG. */
24629 {
24634 else
24636 }
24643 /* Check for mixed types and values. */
24651 {
24654 {
24655 /* First try to match ARG directly. */
24657 explain_p);
24659 {
24660 /* Otherwise, look for a suitable base of ARG, as below. */
24667 }
24668 }
24669 /* ARG must be constructed from a template class or a template
24670 template parameter. */
24675 /* Deduce arguments T, i from TT<T> or TT<i>. */
24681 /* If the template is a template template parameter, use the
24682 TEMPLATE_TEMPLATE_PARM for matching. */
24685 /* Fall through to deduce template name. */
24686 }
24690 {
24691 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
24693 /* Simple cases: Value already set, does match or doesn't. */
24698 }
24699 else
24700 {
24701 /* If PARM is `const T' and ARG is only `int', we don't have
24702 a match unless we are allowing additional qualification.
24703 If ARG is `const int' and PARM is just `T' that's OK;
24704 that binds `const int' to `T'. */
24709 /* Consider the case where ARG is `const volatile int' and
24710 PARM is `const T'. Then, T should be `volatile int'. */
24711 arg = cp_build_qualified_type
24716 /* Simple cases: Value already set, does match or doesn't. */
24722 /* Make sure that ARG is not a variable-sized array. (Note
24723 that were talking about variable-sized arrays (like
24724 `int[n]'), rather than arrays of unknown size (like
24725 `int[]').) We'll get very confused by such a type since
24726 the bound of the array is not constant, and therefore
24727 not mangleable. Besides, such types are not allowed in
24728 ISO C++, so we can do as we please here. We do allow
24729 them for 'auto' deduction, since that isn't ABI-exposed. */
24733 /* Strip typedefs as in convert_template_argument. */
24735 }
24737 /* If ARG is a parameter pack or an expansion, we cannot unify
24738 against it unless PARM is also a parameter pack. */
24743 /* If the argument deduction results is a METHOD_TYPE,
24744 then there is a problem.
24745 METHOD_TYPE doesn't map to any real C++ type the result of
24746 the deduction cannot be of that type. */
24760 {
24761 /* The PARM is not one we're trying to unify. Just check
24762 to see if it matches ARG. */
24768 }
24774 {
24778 /* We're deducing from an array bound, the type doesn't matter.
24779 This conversion should match the one below. */
24785 }
24787 /* [temp.deduct.type] If, in the declaration of a function template
24788 with a non-type template-parameter, the non-type
24789 template-parameter is used in an expression in the function
24790 parameter-list and, if the corresponding template-argument is
24791 deduced, the template-argument type shall match the type of the
24792 template-parameter exactly, except that a template-argument
24793 deduced from an array bound may be of any integral type.
24794 The non-type parameter might use already deduced type parameters. */
24797 /* We don't have enough levels of args to do any substitution. This
24799 else
24800 {
24806 {
24809 LOOKUP_NORMAL,
24813 }
24814 }
24818 /* Template-parameter dependent expression. Just accept it for now.
24819 It will later be processed in convert_template_argument. */
24820 ;
24824 /* OK. Ignore top-level quals here because a class-type template
24828 /* Convert the ARG to the type of PARM; the deduced non-type
24829 template argument must exactly match the types of the
24830 corresponding parameter. This conversion should match the
24831 one above. */
24834 {
24835 /* We haven't deduced the type of this parameter yet. */
24837 /* We deduce from array bounds in try_array_deduction. */
24840 {
24841 /* Deduce it from the non-type argument. As above, ignore
24842 top-level quals here too. */
24847 /* Now check whether the type of this parameter is still
24848 dependent, and give up if so. */
24854 }
24855 else
24856 /* Try again later. */
24858 }
24859 else
24862 /* If ARG is a parameter pack or an expansion, we cannot unify
24863 against it unless PARM is also a parameter pack. */
24868 {
24871 }
24876 {
24877 /* A pointer-to-member constant can be unified only with
24878 another constant. */
24882 /* Just unify the class member. It would be useless (and possibly
24883 wrong, depending on the strict flags) to unify also
24884 PTRMEM_CST_CLASS, because we want to be sure that both parm and
24885 arg refer to the same variable, even if through different
24886 classes. For instance:
24888 struct A { int x; };
24889 struct B : A { };
24891 Unification of &A::x and &B::x must succeed. */
24894 }
24897 {
24901 /* [temp.deduct.call]
24903 A can be another pointer or pointer to member type that can
24904 be converted to the deduced A via a qualification
24905 conversion (_conv.qual_).
24907 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
24908 This will allow for additional cv-qualification of the
24909 pointed-to types if appropriate. */
24912 /* The derived-to-base conversion only persists through one
24913 level of pointers. */
24918 }
24951 /* We have already checked cv-qualification at the top of the
24952 function. */
24956 /* As far as unification is concerned, this wins. Later checks
24957 will invalidate it if necessary. */
24960 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
24961 /* Type INTEGER_CST can come from ordinary constant template args. */
24974 {
24984 /* Check for pack expansions in the parameters. */
24986 {
24988 {
24990 /* We can unify against something with a trailing
24991 parameter pack. */
24993 else
24994 /* [temp.deduct.type]/9: If the template argument list of
24995 P contains a pack expansion that is not the last
24996 template argument, the entire template argument list
24997 is a non-deduced context. */
24999 }
25000 }
25002 /* If we don't have enough arguments to satisfy the parameters
25003 (not counting the pack expression at the end), or we have
25004 too many arguments for a parameter list that doesn't end in
25005 a pack expression, we can't unify. */
25011 /* Unify all of the parameters that precede the (optional)
25012 pack expression. */
25014 {
25019 }
25022 DEDUCE_EXACT,
25025 }
25033 {
25041 }
25046 {
25050 {
25051 /* First, we try to unify the PARM and ARG directly. */
25056 {
25057 /* Fallback to the special case allowed in
25058 [temp.deduct.call]:
25060 If P is a class, and P has the form
25061 template-id, then A can be a derived class of
25062 the deduced A. Likewise, if P is a pointer to
25063 a class of the form template-id, A can be a
25064 pointer to a derived class pointed to by the
25065 deduced A. */
25071 {
25072 /* Don't give the derived diagnostic if we're
25073 already dealing with the same template. */
25074 bool same_template
25080 }
25081 }
25082 }
25086 /* Perhaps PARM is something like S<U> and ARG is S<int>.
25087 Then, we should unify `int' and `U'. */
25089 else
25090 /* There's no chance of unification succeeding. */
25095 }
25102 {
25105 tree a;
25111 /* CV qualifications for methods can never be deduced, they must
25112 match exactly. We need to check them explicitly here,
25113 because type_unification_real treats them as any other
25114 cv-qualified parameter. */
25116 && (!check_cv_quals_for_unify
25144 {
25154 else
25155 {
25158 /* Here "less cv-qual" means the deduced arg (i.e. parm) has
25159 /more/ noexcept, since function pointer conversions are the
25160 reverse of qualification conversions. */
25165 else
25167 }
25168 }
25170 {
25171 /* As for noexcept. */
25178 else
25180 }
25183 }
25186 /* Unify a pointer to member with a pointer to member function, which
25187 deduces the type of the member as a function type. */
25189 {
25190 /* Check top-level cv qualifiers */
25198 /* Determine the type of the function we are unifying against. */
25202 }
25221 /* Matched cases are handled by the ARG == PARM test above. */
25225 /* We might get a variable as a non-type template argument in parm if the
25226 corresponding parameter is type-dependent. Make any necessary
25227 adjustments based on whether arg is a reference. */
25231 {
25236 }
25237 /* Now use the normal expression code to check whether they match. */
25248 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
25249 or TRAIT_TYPE nodes. */
25253 /* Unification fails if we hit an error node. */
25258 {
25268 }
25269 /* FALLTHRU */
25272 /* An unresolved overload is a nondeduced context. */
25278 expr:
25279 /* We must be looking at an expression. This can happen with
25280 something like:
25282 template <int I>
25283 void foo(S<I>, S<I + 2>);
25285 or
25287 template<typename T>
25288 void foo(A<T, T{}>);
25290 This is a "non-deduced context":
25292 [deduct.type]
25294 The non-deduced contexts are:
25296 --A non-type template argument or an array bound in which
25297 a subexpression references a template parameter.
25299 In these cases, we assume deduction succeeded, but don't
25300 actually infer any unifications. */
25305 else
25307 }
25308 }
25309 #undef RECUR_AND_CHECK_FAILURE
25310 \f
25311 /* Note that DECL can be defined in this translation unit, if
25312 required. */
25314 static void
25316 {
25317 tree clone;
25321 }
25323 /* Called if RESULT is explicitly instantiated, or is a member of an
25324 explicitly instantiated class. */
25326 void
25328 {
25331 /* If this entity has already been written out, it's too late to
25332 make any modifications. */
25336 /* consteval functions are never emitted. */
25341 /* For anonymous namespace we don't need to do anything. */
25343 {
25346 }
25349 /* The TREE_PUBLIC flag for function declarations will have been
25350 set correctly by tsubst. */
25354 {
25357 }
25358 else
25359 {
25362 /* Always make artificials weak. */
25365 /* For WIN32 we also want to put explicit instantiations in
25366 linkonce sections. */
25371 /* If the function has already been instantiated, clear DECL_EXTERNAL,
25372 since start_preparsed_function wouldn't have if we had an earlier
25373 extern explicit instantiation. */
25375 }
25377 /* If EXTERN_P, then this function will not be emitted -- unless
25378 followed by an explicit instantiation, at which point its linkage
25379 will be adjusted. If !EXTERN_P, then this function will be
25380 emitted here. In neither circumstance do we want
25381 import_export_decl to adjust the linkage. */
25383 }
25385 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
25386 important template arguments. If any are missing, we check whether
25387 they're important by using error_mark_node for substituting into any
25388 args that were used for partial ordering (the ones between ARGS and END)
25389 and seeing if it bubbles up. */
25391 static bool
25393 {
25397 {
25400 }
25402 {
25406 }
25408 }
25410 /* Given two function templates PAT1 and PAT2, return:
25412 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
25413 -1 if PAT2 is more specialized than PAT1.
25414 0 if neither is more specialized.
25416 LEN indicates the number of parameters we should consider
25417 (defaulted parameters should not be considered).
25419 The 1998 std underspecified function template partial ordering, and
25420 DR214 addresses the issue. We take pairs of arguments, one from
25421 each of the templates, and deduce them against each other. One of
25422 the templates will be more specialized if all the *other*
25423 template's arguments deduce against its arguments and at least one
25424 of its arguments *does* *not* deduce against the other template's
25425 corresponding argument. Deduction is done as for class templates.
25426 The arguments used in deduction have reference and top level cv
25427 qualifiers removed. Iff both arguments were originally reference
25428 types *and* deduction succeeds in both directions, an lvalue reference
25429 wins against an rvalue reference and otherwise the template
25430 with the more cv-qualified argument wins for that pairing (if
25431 neither is more cv-qualified, they both are equal). Unlike regular
25432 deduction, after all the arguments have been deduced in this way,
25433 we do *not* verify the deduced template argument values can be
25434 substituted into non-deduced contexts.
25436 The logic can be a bit confusing here, because we look at deduce1 and
25437 targs1 to see if pat2 is at least as specialized, and vice versa; if we
25438 can find template arguments for pat1 to make arg1 look like arg2, that
25439 means that arg2 is at least as specialized as arg1. */
25441 int
25443 {
25456 /* Remove the this parameter from non-static member functions. If
25457 one is a non-static member function and the other is not a static
25458 member function, remove the first parameter from that function
25459 also. This situation occurs for operator functions where we
25460 locate both a member function (with this pointer) and non-member
25461 operator (with explicit first operand). */
25463 {
25468 }
25470 {
25473 {
25474 len--;
25476 }
25477 }
25479 /* If only one is a conversion operator, they are unordered. */
25483 /* Consider the return type for a conversion function */
25485 {
25488 len++;
25489 }
25491 processing_template_decl++;
25497 /* Stop when an ellipsis is seen. */
25499 {
25510 {
25511 /* When both arguments are pack expansions, we need only
25512 unify the patterns themselves. */
25516 /* This is the last comparison we need to do. */
25518 }
25521 {
25525 }
25528 {
25532 }
25538 {
25544 /* Setup the parameter vector, which contains only ARG1. */
25547 /* Setup the argument vector, which contains the remaining
25548 arguments. */
25557 /* We cannot deduce in the other direction, because ARG1 is
25558 a pack expansion but ARG2 is not. */
25560 }
25562 {
25568 /* Setup the parameter vector, which contains only ARG1. */
25571 /* Setup the argument vector, which contains the remaining
25572 arguments. */
25581 /* We cannot deduce in the other direction, because ARG2 is
25582 a pack expansion but ARG1 is not.*/
25584 }
25586 else
25587 {
25588 /* The normal case, where neither argument is a pack
25589 expansion. */
25596 }
25598 /* If we couldn't deduce arguments for tparms1 to make arg1 match
25599 arg2, then arg2 is not as specialized as arg1. */
25605 /* "If, for a given type, deduction succeeds in both directions
25606 (i.e., the types are identical after the transformations above)
25607 and both P and A were reference types (before being replaced with
25608 the type referred to above):
25609 - if the type from the argument template was an lvalue reference and
25610 the type from the parameter template was not, the argument type is
25611 considered to be more specialized than the other; otherwise,
25612 - if the type from the argument template is more cv-qualified
25613 than the type from the parameter template (as described above),
25614 the argument type is considered to be more specialized than the other;
25615 otherwise,
25616 - neither type is more specialized than the other." */
25619 {
25621 {
25624 else
25626 }
25628 {
25633 }
25634 }
25637 /* We've failed to deduce something in either direction.
25638 These must be unordered. */
25643 /* We have already processed all of the arguments in our
25644 handing of the pack expansion type. */
25649 }
25651 /* "In most cases, all template parameters must have values in order for
25652 deduction to succeed, but for partial ordering purposes a template
25653 parameter may remain without a value provided it is not used in the
25654 types being used for partial ordering."
25656 Thus, if we are missing any of the targs1 we need to substitute into
25657 origs1, then pat2 is not as specialized as pat1. This can happen when
25658 there is a nondeduced context. */
25664 processing_template_decl--;
25666 /* If both deductions succeed, the partial ordering selects the more
25667 constrained template. */
25668 /* P2113: If the corresponding template-parameters of the
25669 template-parameter-lists are not equivalent ([temp.over.link]) or if
25670 the function parameters that positionally correspond between the two
25671 templates are not of the same type, neither template is more
25672 specialized than the other. */
25677 {
25683 }
25685 /* All things being equal, if the next argument is a pack expansion
25686 for one function but not for the other, prefer the
25687 non-variadic function. FIXME this is bogus; see c++/41958. */
25691 {
25694 }
25700 else
25702 }
25704 /* Determine which of two partial specializations of TMPL is more
25705 specialized.
25707 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
25708 to the first partial specialization. The TREE_PURPOSE is the
25709 innermost set of template parameters for the partial
25710 specialization. PAT2 is similar, but for the second template.
25712 Return 1 if the first partial specialization is more specialized;
25713 -1 if the second is more specialized; 0 if neither is more
25714 specialized.
25716 See [temp.class.order] for information about determining which of
25717 two templates is more specialized. */
25719 static int
25721 {
25722 tree targs;
25731 /* Just like what happens for functions, if we are ordering between
25732 different template specializations, we may encounter dependent
25733 types in the arguments, and we need our dependency check functions
25734 to behave correctly. */
25738 {
25741 }
25745 {
25748 }
25751 /* If both deductions succeed, the partial ordering selects the more
25752 constrained template. */
25756 /* In the case of a tie where at least one of the templates
25757 has a parameter pack at the end, the template with the most
25758 non-packed parameters wins. */
25760 && any_deductions
25763 {
25769 /* We don't count the pack expansion at the end. */
25779 }
25782 }
25784 /* Return the template arguments that will produce the function signature
25785 DECL from the function template FN, with the explicit template
25786 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
25787 also match. Return NULL_TREE if no satisfactory arguments could be
25788 found. */
25790 static tree
25792 {
25796 tree decl_arg_types;
25799 tree arg;
25803 /* Never do unification on the 'this' parameter. */
25825 }
25827 /* Return the innermost template arguments that, when applied to a partial
25828 specialization SPEC_TMPL of TMPL, yield the ARGS.
25830 For example, suppose we have:
25832 template <class T, class U> struct S {};
25833 template <class T> struct S<T*, int> {};
25835 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
25836 partial specialization and the ARGS will be {double*, int}. The resulting
25837 vector will be {double}, indicating that `T' is bound to `double'. */
25839 static tree
25841 {
25843 tree spec_args
25846 tree deduced_args;
25847 tree innermost_deduced_args;
25851 {
25855 innermost_deduced_args);
25856 }
25857 else
25861 again:
25870 {
25872 {
25878 }
25880 }
25883 {
25886 }
25888 /* Verify that nondeduced template arguments agree with the type
25889 obtained from argument deduction.
25891 For example:
25893 struct A { typedef int X; };
25894 template <class T, class U> struct C {};
25895 template <class T> struct C<T, typename T::X> {};
25897 Then with the instantiation `C<A, int>', we can deduce that
25898 `T' is `A' but unify () does not check whether `typename T::X'
25899 is `int'. */
25910 /* We only need to check the innermost arguments; the other
25911 arguments will always agree. */
25916 /* Now that we have bindings for all of the template arguments,
25917 ensure that the arguments deduced for the template template
25918 parameters have compatible template parameter lists. See the use
25919 of template_template_parm_bindings_ok_p in fn_type_unification
25920 for more information. */
25925 }
25927 // Compare two function templates T1 and T2 by deducing bindings
25928 // from one against the other. If both deductions succeed, compare
25929 // constraints to see which is more constrained.
25930 static int
25932 {
25937 {
25940 }
25943 {
25946 }
25948 // If both deductions succeed, then one may be more constrained.
25953 }
25955 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
25956 Return the TREE_LIST node with the most specialized template, if
25957 any. If there is no most specialized template, the error_mark_node
25958 is returned.
25960 Note that this function does not look at, or modify, the
25961 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
25962 returned is one of the elements of INSTANTIATIONS, callers may
25963 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
25964 and retrieve it from the value returned. */
25966 tree
25968 {
25975 {
25981 {
25982 /* Equally specialized, move to next function. If there
25983 is no next function, nothing's most specialized. */
25988 }
25989 }
25992 /* Now verify that champ is better than everything earlier in the
25993 instantiation list. */
25996 {
25999 }
26000 }
26002 processing_template_decl--;
26008 }
26010 /* If DECL is a specialization of some template, return the most
26011 general such template. Otherwise, returns NULL_TREE.
26013 For example, given:
26015 template <class T> struct S { template <class U> void f(U); };
26017 if TMPL is `template <class U> void S<int>::f(U)' this will return
26018 the full template. This function will not trace past partial
26019 specializations, however. For example, given in addition:
26021 template <class T> struct S<T*> { template <class U> void f(U); };
26023 if TMPL is `template <class U> void S<int*>::f(U)' this will return
26024 `template <class T> template <class U> S<T*>::f(U)'. */
26026 tree
26028 {
26030 {
26033 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
26034 template friend, or a FIELD_DECL for a capture pack. */
26037 }
26042 /* Look for more and more general templates. */
26044 {
26045 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
26046 (See cp-tree.h for details.) */
26055 /* Stop if we run into an explicitly specialized class template. */
26062 }
26065 }
26067 /* Return the most specialized of the template partial specializations
26068 which can produce TARGET, a specialization of some class or variable
26069 template. The value returned is a TEMPLATE_INFO; the TI_TEMPLATE is a
26070 TEMPLATE_DECL node corresponding to the partial specialization, while
26071 the TI_ARGS is the set of template arguments that must be substituted
26072 into the template pattern in order to generate TARGET. The result is
26073 cached in the TI_PARTIAL_INFO of the corresponding TEMPLATE_INFO unless
26074 RECHECKING is true.
26076 If the choice of partial specialization is ambiguous, a diagnostic
26077 is issued, and the error_mark_node is returned. If there are no
26078 partial specializations matching TARGET, then NULL_TREE is
26079 returned, indicating that the primary template should be used. */
26081 tree
26084 {
26088 {
26093 }
26095 {
26099 }
26101 {
26106 }
26107 else
26114 && tinfo
26121 /* There are no partial specializations of this template. */
26127 /* For determining which partial specialization to use, only the
26128 innermost args are interesting. */
26131 {
26134 }
26136 /* The caller hasn't called push_to_top_level yet, but we need
26137 get_partial_spec_bindings to be done in non-template context so that we'll
26138 fully resolve everything. */
26139 processing_template_decl_sentinel ptds;
26143 {
26146 tree spec_tmpl;
26148 {
26149 /* Substitute in the template args from the enclosing class. */
26155 }
26156 else
26161 {
26165 /* Keep the candidate only if its constraints are satisfied. */
26168 }
26169 }
26177 {
26180 ;
26181 else
26182 {
26184 {
26187 {
26190 }
26191 }
26193 }
26194 }
26198 {
26201 {
26204 }
26205 }
26208 {
26215 else
26219 {
26224 }
26227 }
26233 }
26235 /* Explicitly instantiate DECL. */
26237 void
26239 {
26244 /* An error occurred, for which grokdeclarator has already issued
26245 an appropriate message. */
26248 {
26251 }
26253 {
26256 else
26259 }
26265 {
26266 /* There is an asymmetry here in the way VAR_DECLs and
26267 FUNCTION_DECLs are handled by grokdeclarator. In the case of
26268 the latter, the DECL we get back will be marked as a
26269 template instantiation, and the appropriate
26270 DECL_TEMPLATE_INFO will be set up. This does not happen for
26271 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
26272 should handle VAR_DECLs as it currently handles
26273 FUNCTION_DECLs. */
26275 {
26278 }
26281 {
26284 }
26286 {
26291 }
26292 }
26294 {
26297 }
26298 else
26301 /* Check for various error cases. Note that if the explicit
26302 instantiation is valid the RESULT will currently be marked as an
26303 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
26304 until we get here. */
26307 {
26308 /* DR 259 [temp.spec].
26310 Both an explicit instantiation and a declaration of an explicit
26311 specialization shall not appear in a program unless the explicit
26312 instantiation follows a declaration of the explicit specialization.
26314 For a given set of template parameters, if an explicit
26315 instantiation of a template appears after a declaration of an
26316 explicit specialization for that template, the explicit
26317 instantiation has no effect. */
26319 }
26321 {
26322 /* [temp.spec]
26324 No program shall explicitly instantiate any template more
26325 than once.
26327 We check DECL_NOT_REALLY_EXTERN so as not to complain when
26328 the first instantiation was `extern' and the second is not,
26329 and EXTERN_P for the opposite case. */
26332 /* If an "extern" explicit instantiation follows an ordinary
26333 explicit instantiation, the template is instantiated. */
26336 }
26338 {
26341 }
26343 {
26346 }
26349 ;
26351 {
26354 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
26357 }
26358 else
26366 }
26368 static void
26370 {
26376 {
26379 }
26380 }
26382 /* Perform an explicit instantiation of template class T. STORAGE, if
26383 non-null, is the RID for extern, inline or static. COMPLAIN is
26384 nonzero if this is called from the parser, zero if called recursively,
26385 since the standard is unclear (as detailed below). */
26387 void
26389 {
26391 {
26395 else
26398 }
26403 {
26406 t);
26408 }
26410 /* At most one of these will be true. */
26416 {
26418 {
26421 "ISO C++ 1998 forbids the use of %<extern%> on "
26423 }
26424 else
26426 "ISO C++ forbids the use of %qE"
26435 else
26437 storage);
26438 }
26441 /* DR 259 [temp.spec].
26443 Both an explicit instantiation and a declaration of an explicit
26444 specialization shall not appear in a program unless the
26445 explicit instantiation follows a declaration of the explicit
26446 specialization.
26448 For a given set of template parameters, if an explicit
26449 instantiation of a template appears after a declaration of an
26450 explicit specialization for that template, the explicit
26451 instantiation has no effect. */
26455 {
26456 /* We've already instantiated the template. */
26458 /* [temp.spec]
26460 No program shall explicitly instantiate any template more
26461 than once.
26463 If EXTERN_P then this is ok. */
26469 }
26477 /* In contrast to implicit instantiation, where only the
26478 declarations, and not the definitions, of members are
26479 instantiated, we have here:
26481 [temp.explicit]
26483 An explicit instantiation that names a class template
26484 specialization is also an explicit instantiation of the same
26485 kind (declaration or definition) of each of its members (not
26486 including members inherited from base classes and members
26487 that are templates) that has not been previously explicitly
26488 specialized in the translation unit containing the explicit
26489 instantiation, provided that the associated constraints, if
26490 any, of that member are satisfied by the template arguments
26491 of the explicit instantiation. */
26495 && !static_p
26499 {
26504 }
26506 {
26512 }
26513 }
26515 /* Given a function DECL, which is a specialization of TMPL, modify
26516 DECL to be a re-instantiation of TMPL with the same template
26517 arguments. TMPL should be the template into which tsubst'ing
26518 should occur for DECL, not the most general template.
26520 One reason for doing this is a scenario like this:
26522 template <class T>
26523 void f(const T&, int i);
26525 void g() { f(3, 7); }
26527 template <class T>
26528 void f(const T& t, const int i) { }
26530 Note that when the template is first instantiated, with
26531 instantiate_template, the resulting DECL will have no name for the
26532 first parameter, and the wrong type for the second. So, when we go
26533 to instantiate the DECL, we regenerate it. */
26535 static void
26537 {
26538 /* The arguments used to instantiate DECL, from the most general
26539 template. */
26542 /* Make sure that we can see identifiers, and compute access correctly. */
26546 {
26547 tree specs;
26551 /* Don't bother with this for unique friends that can't be redeclared and
26552 might change type if regenerated (PR69836). */
26556 /* Use the source location of the definition. */
26564 /* Instantiate a dynamic exception-specification. noexcept will be
26565 handled below. */
26568 {
26574 specs);
26575 }
26577 /* Merge parameter declarations. */
26581 {
26588 }
26591 {
26592 /* If we're regenerating a specialization, the contracts will have
26593 been copied from the most general template. Replace those with
26594 the ones from the actual specialization. */
26597 {
26600 }
26603 }
26605 /* Merge additional specifiers from the CODE_PATTERN. */
26611 }
26613 {
26622 }
26623 else
26626 done:
26628 }
26630 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
26631 substituted to get DECL. */
26633 tree
26635 {
26638 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
26639 for the instantiation. This is not always the most general
26640 template. Consider, for example:
26642 template <class T>
26643 struct S { template <class U> void f();
26644 template <> void f<int>(); };
26646 and an instantiation of S<double>::f<int>. We want TD to be the
26647 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
26649 more general template. */
26651 /* We must also deal with friend templates. Given:
26653 template <class T> struct S {
26654 template <class U> friend void f() {};
26655 };
26657 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
26658 so far as the language is concerned, but that's still
26659 where we get the pattern for the instantiation from. On
26660 other hand, if the definition comes outside the class, say:
26662 template <class T> struct S {
26663 template <class U> friend void f();
26664 };
26665 template <class U> friend void f() {}
26667 we don't need to look any further. That's what the check for
26668 DECL_INITIAL is for. */
26672 {
26673 /* The present template, TD, should not be a definition. If it
26674 were a definition, we should be using it! Note that we
26675 cannot restructure the loop to just keep going until we find
26676 a template with a definition, since that might go too far if
26677 a specialization was declared, but not defined. */
26679 /* Fetch the more general template. */
26681 }
26684 }
26686 /* Returns true if we need to instantiate this template instance even if we
26687 know we aren't going to emit it. */
26689 bool
26691 {
26692 /* We always instantiate inline functions so that we can inline them. An
26693 explicit instantiation declaration prohibits implicit instantiation of
26694 non-inline functions. With high levels of optimization, we would
26695 normally inline non-inline functions -- but we're not allowed to do
26696 that for "extern template" functions. Therefore, we check
26697 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
26701 /* And we need to instantiate static data members so that
26702 their initializers are available in integral constant
26703 expressions. */
26706 }
26708 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
26709 instantiate it now, modifying TREE_TYPE (fn). Returns false on
26710 error, true otherwise. */
26712 bool
26714 {
26718 /* Don't instantiate a noexcept-specification from template context. */
26728 {
26730 /* We're in start_preparsed_function, keep going. */
26737 }
26748 /* For a member friend template we can get a TEMPLATE_DECL. Let's use
26749 its FUNCTION_DECL for the rest of this function -- push_access_scope
26750 doesn't accept TEMPLATE_DECLs. */
26752 {
26755 }
26758 {
26763 }
26765 {
26769 {
26772 /* This might have failed because of an unparsed DMI, so
26773 let's try again later. */
26775 }
26777 {
26778 /* If hash_set::add returns true, the element was already there. */
26783 fn);
26785 }
26787 {
26795 {
26796 /* If needed, set current_class_ptr for the benefit of
26797 tsubst_copy/PARM_DECL. */
26802 }
26804 /* If this function is represented by a TEMPLATE_DECL, then
26805 the deferred noexcept-specification might still contain
26806 dependent types, even after substitution. And we need the
26807 dependency check functions to work in build_noexcept_spec. */
26811 /* Do deferred instantiation of the noexcept-specifier. */
26816 /* Build up the noexcept-specification. */
26826 }
26827 else
26832 }
26835 {
26836 /* This failed with a hard error, so let's go with false. */
26839 }
26846 }
26848 /* We're starting to process the function INST, an instantiation of PATTERN;
26849 add their parameters to local_specializations. */
26851 void
26853 {
26857 {
26861 }
26863 {
26865 {
26868 }
26869 else
26870 {
26871 /* Register the (value) argument pack as a specialization of
26872 TMPL_PARM, then move on. */
26875 }
26876 }
26878 }
26880 /* Instantiate the body of D using PATTERN with ARGS. We have
26881 already determined PATTERN is the correct template to use.
26882 NESTED_P is true if this is a nested function, in which case
26883 PATTERN will be a FUNCTION_DECL not a TEMPLATE_DECL. */
26885 static void
26887 {
26892 {
26895 }
26896 else
26897 /* Only OMP reductions are nested. */
26909 {
26910 /* The variable might be a lambda's extra scope, and that
26911 lambda's visibility depends on D's. */
26914 }
26916 /* Mark D as instantiated so that recursive calls to
26917 instantiate_decl do not try to instantiate it again. */
26921 /* Regenerate the declaration in case the template has been modified
26922 by a subsequent redeclaration. */
26925 /* We already set the file and line above. Reset them now in case
26926 they changed as a result of calling regenerate_decl_from_template. */
26930 {
26931 /* Clear out DECL_RTL; whatever was there before may not be right
26932 since we've reset the type of the declaration. */
26936 /* The initializer is placed in DECL_INITIAL by
26937 regenerate_decl_from_template so we don't need to
26938 push/pop_access_scope again here. Pull it out so that
26939 cp_finish_decl can process it. */
26945 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
26946 initializer. That function will defer actual emission until
26947 we have a chance to determine linkage. */
26950 /* Enter the scope of D so that access-checking works correctly. */
26960 }
26964 {
26965 /* Set up the list of local specializations. */
26969 /* Set up context. */
26972 else
26973 {
26977 }
26979 /* Create substitution entries for the parameters. */
26982 /* Substitute into the body of the function. */
26986 else
26987 {
26991 /* Set the current input_location to the end of the function
26992 so that finish_function knows where we are. */
26993 input_location
26996 /* Remember if we saw an infinite loop in the template. */
26997 current_function_infinite_loop
26999 }
27001 /* Finish the function. */
27004 else
27005 {
27008 }
27012 }
27014 /* We're not deferring instantiation any more. */
27022 }
27024 /* Produce the definition of D, a _DECL generated from a template. If
27025 DEFER_OK is true, then we don't have to actually do the
27026 instantiation now; we just have to do it sometime. Normally it is
27027 an error if this is an explicit instantiation but D is undefined.
27028 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
27029 instantiated class template. */
27031 tree
27033 {
27035 tree gen_args;
27036 tree args;
27037 tree td;
27038 tree code_pattern;
27039 tree spec;
27040 tree gen_tmpl;
27048 /* This function should only be used to instantiate templates for
27049 functions and static member variables. */
27052 /* A concept is never instantiated. */
27058 /* We may have a pending instantiation of D itself. */
27061 /* Variables are never deferred; if instantiation is required, they
27062 are instantiated right away. That allows for better code in the
27063 case that an expression refers to the value of the variable --
27064 if the variable has a constant value the referring expression can
27065 take advantage of that fact. */
27069 /* Don't instantiate cloned functions. Instead, instantiate the
27070 functions they cloned. */
27079 /* D has already been instantiated or explicitly specialized, so
27080 there's nothing for us to do here.
27082 It might seem reasonable to check whether or not D is an explicit
27083 instantiation, and, if so, stop here. But when an explicit
27084 instantiation is deferred until the end of the compilation,
27085 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
27086 the instantiation. */
27089 /* Check to see whether we know that this template will be
27090 instantiated in some other file, as with "extern template"
27091 extension. */
27094 /* In general, we do not instantiate such templates. */
27101 /* We should already have the extra args. */
27105 /* And what's in the hash table should match D. */
27107 == d
27110 /* This needs to happen before any tsubsting. */
27116 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
27117 for the instantiation. */
27122 {
27123 /* Look up an explicit specialization, if any. */
27126 {
27129 }
27130 }
27134 /* We should never be trying to instantiate a member of a class
27135 template or partial specialization. */
27140 /* In the case of a friend template whose definition is provided
27141 outside the class, we may have too many arguments. Drop the
27142 ones we don't need. The same is true for specializations. */
27143 args = get_innermost_template_args
27147 {
27153 }
27154 else
27155 {
27159 else
27161 }
27163 /* We may be in the middle of deferred access check. Disable it now. */
27166 /* Unless an explicit instantiation directive has already determined
27167 the linkage of D, remember that a definition is available for
27168 this entity. */
27178 /* If D is a member of an explicitly instantiated class template,
27179 and no definition is available, treat it like an implicit
27180 instantiation. */
27183 {
27184 /* Leave linkage flags alone on instantiations with anonymous
27185 visibility. */
27187 {
27190 }
27192 }
27194 /* Defer all other templates, unless we have been explicitly
27195 forbidden from doing so. */
27197 template. */
27198 ! pattern_defined
27199 /* If it's OK to postpone instantiation, do so. */
27200 || defer_ok
27201 /* If this is a static data member that will be defined
27202 elsewhere, we don't want to instantiate the entire data
27203 member, but we do want to instantiate the initializer so that
27204 we can substitute that elsewhere. */
27206 /* Handle here a deleted function too, avoid generating
27207 its body (c++/61080). */
27209 {
27210 /* The definition of the static data member is now required so
27211 we must substitute the initializer. */
27215 {
27216 tree ns;
27217 tree init;
27226 args,
27228 /* If instantiating the initializer involved instantiating this
27229 again, don't call cp_finish_decl twice. */
27231 {
27232 /* Make sure the initializer is still constant, in case of
27233 circular dependency (template/instantiate6.C). */
27234 const_init
27238 }
27242 }
27244 /* We restore the source position here because it's used by
27245 add_pending_template. */
27251 /* [temp.explicit]
27253 The definition of a non-exported function template, a
27254 non-exported member function template, or a non-exported
27255 member function or static data member of a class template
27256 shall be present in every translation unit in which it is
27257 explicitly instantiated. */
27261 /* If we're in unevaluated context, we just wanted to get the
27262 constant value; this isn't an odr use, so don't queue
27263 a full instantiation. */
27265 /* ??? Historically, we have instantiated inline functions, even
27266 when marked as "extern template". */
27269 }
27270 else
27271 {
27276 }
27285 }
27287 /* Run through the list of templates that we wish we could
27288 instantiate, and instantiate any we can. RETRIES is the
27289 number of times we retry pending template instantiation. */
27291 void
27293 {
27297 /* Instantiating templates may trigger vtable generation. This in turn
27298 may require further template instantiations. We place a limit here
27299 to avoid infinite loop. */
27301 {
27305 "template instantiation depth exceeds maximum of %d"
27306 " instantiating %q+D, possibly from virtual table generation"
27310 /* Pretend that we defined it. */
27313 }
27315 do
27316 {
27321 {
27326 {
27328 {
27343 }
27346 }
27347 else
27348 {
27351 {
27352 instantiation
27358 }
27362 }
27365 {
27366 /* If INSTANTIATION has been instantiated, then we don't
27367 need to consider it again in the future. */
27372 }
27373 else
27374 {
27377 }
27380 }
27382 }
27386 }
27388 /* Substitute ARGVEC into T, which is a list of initializers for
27389 either base class or a non-static data member. The TREE_PURPOSEs
27390 are DECLs, and the TREE_VALUEs are the initializer values. Used by
27391 instantiate_decl. */
27393 static tree
27395 {
27400 {
27401 tree decl;
27402 tree init;
27408 {
27409 tree expr;
27410 tree arg;
27412 /* Expand the base class expansion type into separate base
27413 classes. */
27415 tf_warning_or_error,
27416 NULL_TREE);
27420 /* We'll be building separate TREE_LISTs of arguments for
27421 each base. */
27427 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
27428 expand each argument in the TREE_VALUE of t. */
27435 /* VOID_TYPE_NODE is used to indicate
27436 value-initialization. */
27437 {
27440 }
27441 else
27442 {
27443 /* Substitute parameter packs into each argument in the
27444 TREE_LIST. */
27447 {
27448 tree expanded_exprs;
27450 /* Expand the argument. */
27451 tree value;
27454 else
27455 {
27458 }
27459 expanded_exprs
27461 tf_warning_or_error,
27462 NULL_TREE);
27466 /* Prepend each of the expanded expressions to the
27467 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
27475 else
27480 }
27483 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
27484 since we built them backwards. */
27486 {
27489 }
27490 }
27491 }
27494 {
27496 {
27500 }
27501 else
27502 {
27503 tree tmp;
27517 /* If we had an initializer but it instantiated to nothing,
27518 value-initialize the object. This will only occur when
27519 the initializer was a pack expansion where the parameter
27520 packs used in that expansion were of length zero. */
27523 }
27527 {
27529 decl);
27531 }
27532 /* Look for a target constructor. */
27536 {
27539 {
27543 }
27545 }
27548 {
27550 /* Carry over the dummy TREE_TYPE node containing the source
27551 location. */
27555 }
27556 }
27557 }
27559 }
27561 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
27562 is the instantiation (which should have been created with
27563 start_enum) and ARGS are the template arguments to use. */
27565 static void
27567 {
27568 tree e;
27574 {
27575 tree value;
27578 /* Note that in a template enum, the TREE_VALUE is the
27579 CONST_DECL, not the corresponding INTEGER_CST. */
27583 /* Give this enumeration constant the correct access. */
27586 /* Actually build the enumerator itself. Here we're assuming that
27587 enumerators can't have dependent attributes. */
27591 /* Attribute deprecated without an argument isn't sticky: it'll
27592 melt into a tree flag, so we need to propagate the flag here,
27593 since we just created a new enumerator. */
27596 }
27608 }
27610 /* DECL is a FUNCTION_DECL that is a template specialization. Return
27611 its type -- but without substituting the innermost set of template
27612 arguments. So, innermost set of template parameters will appear in
27613 the type. */
27615 tree
27617 {
27618 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
27620 }
27622 /* Return truthvalue if we're processing a template different from
27623 the last one involved in diagnostics. */
27624 bool
27626 {
27628 }
27630 /* Remember current template involved in diagnostics. */
27631 void
27633 {
27635 }
27639 {
27641 }
27643 /* Return TRUE if current_function_decl is being instantiated, false
27644 otherwise. */
27646 bool
27648 {
27652 }
27654 /* [temp.param] Check that template non-type parm TYPE is of an allowable
27655 type. Return false for ok, true for disallowed. Issue error and
27656 inform messages under control of COMPLAIN. */
27658 static bool
27660 {
27671 {
27673 {
27678 }
27680 }
27685 /* Fall through; before C++11 alias templates, a bound ttp
27688 /* Any other wildcard type not already handled above is allowed. */
27695 {
27703 {
27704 auto_diagnostic_group d;
27708 }
27710 }
27712 {
27717 }
27720 {
27723 else
27725 type);
27726 }
27728 }
27730 /* Returns true iff the noexcept-specifier for TYPE is value-dependent. */
27732 static bool
27734 {
27737 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
27738 affect overload resolution and treating it as dependent breaks
27739 things. Same for an unparsed noexcept expression. */
27746 }
27748 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
27749 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
27751 static bool
27753 {
27754 tree scope;
27756 /* [temp.dep.type]
27758 A type is dependent if it is:
27760 -- a template parameter. Template template parameters are types
27761 for us (since TYPE_P holds true for them) so we handle
27762 them here. */
27766 /* -- a qualified-id with a nested-name-specifier which contains a
27767 class-name that names a dependent type or whose unqualified-id
27768 names a dependent type. */
27772 /* An alias template specialization can be dependent even if the
27773 resulting type is not. */
27777 /* -- a cv-qualified type where the cv-unqualified type is
27778 dependent.
27779 No code is necessary for this bullet; the code below handles
27780 cv-qualified types, and we don't want to strip aliases with
27781 TYPE_MAIN_VARIANT because of DR 1558. */
27782 /* -- a compound type constructed from any dependent type. */
27790 {
27791 tree arg_type;
27796 arg_type;
27802 /* A value-dependent noexcept-specifier makes the type dependent. */
27805 }
27806 /* -- an array type constructed from any dependent type or whose
27807 size is specified by a constant expression that is
27808 value-dependent.
27810 We checked for type- and value-dependence of the bounds in
27811 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
27813 {
27818 }
27820 /* -- a template-id in which either the template name is a template
27821 parameter ... */
27824 /* ... or any of the template arguments is a dependent type or
27825 an expression that is type-dependent or value-dependent. */
27827 && (any_dependent_template_arguments_p
27831 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and TRAIT_TYPEs are
27832 dependent; if the argument of the `typeof' expression is not
27833 type-dependent, then it should already been have resolved. */
27839 /* A template argument pack is dependent if any of its packed
27840 arguments are. */
27842 {
27847 }
27849 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
27850 be template parameters. */
27860 /* The standard does not specifically mention types that are local
27861 to template functions or local classes, but they should be
27862 considered dependent too. For example:
27864 template <int I> void f() {
27865 enum E { a = I };
27866 S<sizeof (E)> s;
27867 }
27869 The size of `E' cannot be known until the value of `I' has been
27870 determined. Therefore, `E' must be considered dependent. */
27874 /* Don't use type_dependent_expression_p here, as it can lead
27875 to infinite recursion trying to determine whether a lambda
27876 nested in a lambda is dependent (c++/47687). */
27880 && (any_dependent_template_arguments_p
27884 /* Other types are non-dependent. */
27886 }
27888 /* Returns TRUE if TYPE is dependent, in the sense of
27889 [temp.dep.type]. Note that a NULL type is considered dependent. */
27891 bool
27893 {
27894 /* If there are no template parameters in scope, then there can't be
27895 any dependent types. */
27897 {
27898 /* If we are not processing a template, then nobody should be
27899 providing us with a dependent type. */
27903 }
27905 /* If the type is NULL, we have not computed a type for the entity
27906 in question; in that case, the type is dependent. */
27910 /* Erroneous types can be considered non-dependent. */
27914 /* If we have not already computed the appropriate value for TYPE,
27915 do so now. */
27917 {
27920 }
27923 }
27925 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
27926 lookup. In other words, a dependent type that is not the current
27927 instantiation. */
27929 bool
27931 {
27934 }
27936 /* True if we might find more declarations in SCOPE during instantiation than
27937 we can when parsing the template. */
27939 bool
27941 {
27943 }
27945 /* T is a SCOPE_REF. Return whether it represents a non-static member of
27946 an unknown base of 'this' (and is therefore instantiation-dependent). */
27948 static bool
27950 {
27967 }
27969 /* T is a SCOPE_REF; return whether we need to consider it
27970 instantiation-dependent so that we can check access at instantiation
27971 time even though we know which member it resolves to. */
27973 static bool
27975 {
27983 else
27985 }
27987 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
27988 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
27989 expression. */
27991 /* Note that this predicate is not appropriate for general expressions;
27992 only constant expressions (that satisfy potential_constant_expression)
27993 can be tested for value dependence. */
27995 bool
27997 {
28001 /* A type-dependent expression is also value-dependent. */
28006 {
28008 /* A dependent member function of the current instantiation. */
28012 /* A dependent member function of the current instantiation. */
28019 /* A name that has not been looked up -- must be dependent. */
28023 /* A non-type template parm. */
28027 /* A non-type template parm. */
28033 /* A constant with literal type and is initialized
28034 with an expression that is value-dependent. */
28038 {
28041 /* __PRETTY_FUNCTION__ inside a template function is dependent
28042 on the name of the function. */
28044 /* It might be used in a template, but not a template
28045 function, in which case its DECL_VALUE_EXPR will be
28046 "top level". */
28049 }
28051 /* FIXME cp_finish_decl doesn't fold reference initializers. */
28053 /* We have a constexpr variable and we're processing a template. When
28054 there's lifetime extension involved (for which finish_compound_literal
28055 used to create a temporary), we'll not be able to evaluate the
28056 variable until instantiating, so pretend it's value-dependent. */
28068 /* These expressions are value-dependent if the type to which
28069 the cast occurs is dependent or the expression being casted
28070 is value-dependent. */
28071 {
28077 /* A functional cast has a list of operands. */
28080 {
28081 /* If there are no operands, it must be an expression such
28082 as "int()". This should not happen for aggregate types
28083 because it would form non-constant expressions. */
28088 }
28098 }
28103 /* FALLTHRU */
28106 /* A `sizeof' expression is value-dependent if the operand is
28107 type-dependent or is a pack expansion. */
28116 /* An 'encode' expression is value-dependent if the operand is
28117 type-dependent. */
28126 /* All instantiation-dependent expressions should also be considered
28127 value-dependent. */
28135 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
28136 is value-dependent. */
28143 {
28159 }
28170 {
28174 }
28177 /* Treat all requires-expressions as value-dependent so
28178 we don't try to fold them. */
28185 {
28192 {
28194 /* In a call to a constexpr member function, look through the
28195 implicit ADDR_EXPR on the object argument so that it doesn't
28196 cause the call to be considered value-dependent. We also
28197 look through it in potential_constant_expression. */
28204 }
28206 }
28213 {
28215 tree val;
28222 }
28225 /* Treat a GNU statement expression as dependent to avoid crashing
28226 under instantiate_non_dependent_expr; it can't be constant. */
28231 /* The second operand is a type, which type_dependent_expression_p
28232 (and therefore value_dependent_expression_p) doesn't want to see. */
28238 /* A constant expression is value-dependent if any subexpression is
28239 value-dependent. */
28241 {
28248 {
28252 {
28255 /* In some cases, some of the operands may be missing.
28256 (For example, in the case of PREDECREMENT_EXPR, the
28257 amount to increment by may be missing.) That doesn't
28258 make the expression dependent. */
28261 }
28262 }
28266 }
28268 }
28270 /* The expression is not value-dependent. */
28272 }
28274 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
28275 [temp.dep.expr]. Note that an expression with no type is
28276 considered dependent. Other parts of the compiler arrange for an
28277 expression with type-dependent subexpressions to have no type, so
28278 this function doesn't have to be fully recursive. */
28280 bool
28282 {
28293 /* An unresolved name is always dependent. */
28299 /* A lambda-expression in template context is dependent. dependent_type_p is
28300 true for a lambda in the scope of a class or function template, but that
28301 doesn't cover all template contexts, like a default template argument. */
28305 /* A fold expression is type-dependent. */
28312 /* Some expression forms are never type-dependent. */
28325 /* The types of these expressions depends only on the type to which
28326 the cast occurs. */
28335 /* The types of these expressions depends only on the type created
28336 by the expression. */
28339 {
28340 /* For NEW_EXPR tree nodes created inside a template, either
28341 the object type itself or a TREE_LIST may appear as the
28342 operand 1. */
28345 /* This is an array type. We need to check array dimensions
28346 as well. */
28348 || value_dependent_expression_p
28350 /* Array type whose dimension has to be deduced. */
28354 else
28356 }
28359 {
28363 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
28364 contains an identifier associated by name lookup with one or more
28365 declarations declared with a dependent type, or...a
28366 nested-name-specifier or qualified-id that names a member of an
28367 unknown specialization. */
28370 }
28380 {
28385 }
28387 /* A static data member of the current instantiation with incomplete
28388 array type is type-dependent, as the definition and specializations
28389 can have different bounds. */
28396 /* An array of unknown bound depending on a variadic parameter, eg:
28398 template<typename... Args>
28399 void foo (Args... args)
28400 {
28401 int arr[] = { args... };
28402 }
28404 template<int... vals>
28405 void bar ()
28406 {
28407 int arr[] = { vals... };
28408 }
28410 If the array has no length and has an initializer, it must be that
28411 we couldn't determine its length in cp_complete_array_type because
28412 it is dependent. */
28420 /* Pull a FUNCTION_DECL out of a BASELINK if we can. */
28422 {
28427 }
28429 /* A function or variable template-id is type-dependent if it has any
28430 dependent template arguments. */
28434 {
28435 /* Consider the innermost template arguments, since those are the ones
28436 that come from the template-id; the template arguments for the
28437 enclosing class do not make it type-dependent unless they are used in
28438 the type of the decl. */
28440 && (any_dependent_template_arguments_p
28443 }
28445 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
28446 type-dependent. Checking this is important for functions with auto return
28447 type, which looks like a dependent type. */
28456 {
28460 }
28462 /* Otherwise, its constraints could still depend on outer template parameters
28463 from its (dependent) scope. */
28465 /* As an optimization, check this cheaper sufficient condition first.
28466 (At this point we've established that we're looking at a member of
28467 a dependent class, so it makes sense to start treating say undeduced
28468 auto as dependent.) */
28473 /* Always dependent, on the number of arguments if nothing else. */
28478 {
28483 {
28489 }
28490 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
28494 /* CO_AWAIT/YIELD_EXPR with unknown type is always dependent. */
28500 {
28505 }
28508 {
28515 }
28524 }
28526 /* The type of a non-type template parm declared with a placeholder type
28527 depends on the corresponding template argument, even though
28528 placeholders are not normally considered dependent. */
28535 /* Dependent type attributes might not have made it from the decl to
28536 the type yet. */
28542 }
28544 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
28545 type-dependent if the expression refers to a member of the current
28546 instantiation and the type of the referenced member is dependent, or the
28547 class member access expression refers to a member of an unknown
28548 specialization.
28550 This function returns true if the OBJECT in such a class member access
28551 expression is of an unknown specialization. */
28553 bool
28555 {
28556 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
28557 dependent. */
28562 }
28564 /* walk_tree callback function for instantiation_dependent_expression_p,
28565 below. Returns non-zero if a dependent subexpression is found. */
28567 static tree
28570 {
28572 {
28573 /* We don't have to worry about decltype currently because decltype
28574 of an instantiation-dependent expr is a dependent type. This
28575 might change depending on the resolution of DR 1172. */
28578 }
28581 {
28582 /* Don't treat an argument list as dependent just because it has no
28583 TREE_TYPE. */
28594 /* We'll check value-dependence separately. */
28597 /* Handle expressions with type operands. */
28602 {
28607 {
28610 else
28611 {
28614 }
28615 }
28617 }
28621 /* In a template, finish_class_member_access_expr creates a
28622 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
28623 type-dependent, so that we can check access control at
28624 instantiation time (PR 42277). See also Core issue 1273. */
28631 else
28634 /* Treat statement-expressions as dependent. */
28638 /* Treat requires-expressions as dependent. */
28649 /* Before C++17, a noexcept-specifier isn't part of the function type
28650 so it doesn't affect type dependence, but we still want to consider it
28651 for instantiation dependence. */
28660 }
28664 else
28666 }
28668 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
28669 sense defined by the ABI:
28671 "An expression is instantiation-dependent if it is type-dependent
28672 or value-dependent, or it has a subexpression that is type-dependent
28673 or value-dependent."
28675 Except don't actually check value-dependence for unevaluated expressions,
28676 because in sizeof(i) we don't care about the value of i. Checking
28677 type-dependence will in turn check value-dependence of array bounds/template
28678 arguments as needed. */
28680 bool
28682 {
28683 tree result;
28694 }
28696 /* As above, but also check value-dependence of the expression as a whole. */
28698 bool
28700 {
28702 || (processing_template_decl
28705 }
28707 /* Like type_dependent_expression_p, but it also works while not processing
28708 a template definition, i.e. during substitution or mangling. */
28710 bool
28712 {
28718 }
28720 /* Returns TRUE if ARGS contains a type-dependent expression. */
28722 bool
28724 {
28733 }
28735 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
28736 expressions) contains any type-dependent expressions. */
28738 bool
28740 {
28746 }
28748 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
28749 expressions) contains any value-dependent expressions. */
28751 bool
28753 {
28759 }
28761 /* Returns TRUE if the ARG (a template argument) is dependent. */
28763 bool
28765 {
28769 /* Assume a template argument that was wrongly written by the user
28770 is dependent. This is consistent with what
28771 any_dependent_template_arguments_p [that calls this function]
28772 does. */
28782 {
28785 /* A member template of a dependent class is not necessarily
28786 type-dependent, but it is a dependent template argument because it
28787 will be a member of an unknown specialization to that template. */
28790 }
28792 {
28798 }
28801 else
28803 }
28805 /* Identify any expressions that use function parms. */
28807 static tree
28809 {
28812 {
28815 }
28817 }
28819 /* Returns true if a type specialization formed using the template
28820 arguments ARGS needs to use structural equality. */
28822 bool
28824 {
28834 {
28837 {
28843 {
28844 /* Look inside the argument pack. */
28847 }
28850 {
28859 /* An any_targ_node argument (added by add_defaults_to_ttp)
28860 makes the corresponding specialization not canonicalizable,
28861 since template_args_equal always return true for it. We
28862 may see this when called from bind_template_template_parm. */
28864 /* Checking current_function_decl because this structural
28865 comparison is only necessary for redeclaration. */
28868 && (cp_walk_tree_without_duplicates
28870 /* The identity of a class template specialization that uses
28871 a function parameter depends on the identity of the function.
28872 And if this specialization appeared in the trailing return
28873 type thereof, we don't know the identity of the function
28874 (e.g. if it's a redeclaration or a new function) until we
28875 form its signature and go through duplicate_decls. Thus
28876 it's unsafe to decide on a canonical type now (which depends
28877 on the DECL_CONTEXT of the function parameter, which can get
28878 mutated after the fact by duplicate_decls), so just require
28879 structural equality in this case (PR52830). */
28881 }
28882 }
28883 }
28886 }
28888 /* Returns true if ARGS (a collection of template arguments) contains
28889 any dependent arguments. */
28891 bool
28893 {
28900 {
28905 }
28908 }
28910 /* Returns true if ARGS contains any errors. */
28912 bool
28914 {
28922 {
28925 else
28927 }
28933 {
28938 }
28941 }
28943 /* Returns TRUE if the template TMPL is type-dependent. */
28945 bool
28947 {
28949 {
28954 }
28956 /* Template template parameters are dependent. */
28960 /* So are names that have not been looked up. */
28964 }
28966 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
28968 bool
28970 {
28973 }
28975 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
28976 are dependent. */
28978 bool
28980 {
28987 {
29012 {
29016 }
29020 {
29024 {
29030 /* If this loop has a class iterator with != comparison
29031 with increment other than i++/++i/i--/--i, make sure the
29032 increment is constant. */
29035 {
29038 else
29042 }
29043 }
29044 }
29045 }
29048 }
29050 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
29051 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
29052 no such TYPE can be found. Note that this function peers inside
29053 uninstantiated templates and therefore should be used only in
29054 extremely limited situations. ONLY_CURRENT_P restricts this
29055 peering to the currently open classes hierarchy (which is required
29056 when comparing types). */
29058 tree
29060 {
29061 tree scope;
29062 tree name;
29063 tree decl;
29065 tree pushed_scope;
29066 tree result;
29071 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
29074 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
29075 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of a
29076 TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL
29077 representing the typedef. In that case TYPE_IDENTIFIER (type) is
29078 not the non-qualified identifier of the TYPENAME_TYPE anymore.
29079 So by getting the TYPE_IDENTIFIER of the _main declaration_ of
29080 the TYPENAME_TYPE instead, we avoid messing up with a possible
29081 typedef variant case. */
29084 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
29085 it first before we can figure out what NAME refers to. */
29087 {
29089 /* Given a class template A with a dependent base with nested type C,
29090 typedef typename A::C::C C will land us here, as trying to resolve
29091 the initial A::C leads to the local C typedef, which leads back to
29092 A::C::C. So we break the recursion now. */
29094 else
29096 }
29097 /* If we don't know what SCOPE refers to, then we cannot resolve the
29098 TYPENAME_TYPE. */
29101 /* If this is a typedef, we don't want to look inside (c++/11987). */
29104 /* If SCOPE isn't the template itself, it will not have a valid
29105 TYPE_FIELDS list. */
29107 /* scope is either the template itself or a compatible instantiation
29108 like X<T>, so look up the name in the original template. */
29110 /* If scope has no fields, it can't be a current instantiation. Check this
29111 before currently_open_class to avoid infinite recursion (71515). */
29114 /* If the SCOPE is not the current instantiation, there's no reason
29115 to look inside it. */
29118 /* Enter the SCOPE so that name lookup will be resolved as if we
29119 were in the class definition. In particular, SCOPE will no
29120 longer be considered a dependent type. */
29122 /* Look up the declaration. */
29124 tf_warning_or_error);
29128 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
29129 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
29135 {
29139 }
29142 {
29143 /* Obtain the template and the arguments. */
29146 {
29147 /* We get here with a plain identifier because a previous tentative
29148 parse of the nested-name-specifier as part of a ptr-operator saw
29149 ::template X<A>. The use of ::template is necessary in a
29150 ptr-operator, but wrong in a declarator-id.
29152 [temp.names]: In a qualified-id of a declarator-id, the keyword
29153 template shall not appear at the top level. */
29157 }
29159 /* Instantiate the template. */
29165 }
29167 /* Leave the SCOPE. */
29171 /* If we failed to resolve it, return the original typename. */
29175 /* If lookup found a typename type, resolve that too. */
29177 {
29178 /* Ill-formed programs can cause infinite recursion here, so we
29179 must catch that. */
29183 }
29185 /* Qualify the resulting type. */
29191 }
29193 /* EXPR is an expression which is not type-dependent. Return a proxy
29194 for EXPR that can be used to compute the types of larger
29195 expressions containing EXPR. */
29197 tree
29199 {
29201 tree inner_expr;
29203 /* When checking, try to get a constant value for all non-dependent
29204 expressions in order to expose bugs in *_dependent_expression_p
29205 and constexpr. This can affect code generation, see PR70704, so
29206 only do this for -fchecking=2. */
29209 /* Don't do this during nsdmi parsing as it can lead to
29210 unexpected recursive instantiations. */
29212 /* Don't do this during concept processing either and for
29213 the same reason. */
29219 /* Preserve OVERLOADs; the functions must be available to resolve
29220 types. */
29231 /* There is no need to return a proxy for a variable, parameter
29232 or enumerator. */
29236 /* Preserve string constants; conversions from string constants to
29237 "char *" are allowed, even though normally a "const char *"
29238 cannot be used to initialize a "char *". */
29241 /* Preserve void and arithmetic constants, as an optimization -- there is no
29242 reason to create a new node. */
29247 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
29248 There is at least one place where we want to know that a
29249 particular expression is a throw-expression: when checking a ?:
29250 expression, there are special rules if the second or third
29251 argument is a throw-expression. */
29255 /* Don't wrap an initializer list, we need to be able to look inside. */
29259 /* Don't wrap a dummy object, we need to be able to test for it. */
29277 /* If the type is unknown, it can't really be non-dependent */
29280 /* Otherwise, build a NON_DEPENDENT_EXPR. */
29283 }
29285 /* ARGS is a vector of expressions as arguments to a function call.
29286 Replace the arguments with equivalent non-dependent expressions.
29287 This modifies ARGS in place. */
29289 void
29291 {
29293 tree arg;
29296 {
29300 }
29301 }
29303 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
29304 TEMPLATE_TYPE_PARM with a level one deeper than the actual template parms,
29305 by default. If set_canonical is true, we set TYPE_CANONICAL on it. */
29307 static tree
29309 {
29325 }
29327 tree
29329 {
29331 }
29333 tree
29335 {
29337 }
29339 /* Return a C++17 deduction placeholder for class template TMPL.
29340 There are represented as an 'auto' with the special level 0 and
29341 CLASS_PLACEHOLDER_TEMPLATE set. */
29343 tree
29345 {
29348 /* Our canonical type depends on the placeholder. */
29351 }
29353 /* True iff T is a C++17 class template deduction placeholder. */
29355 bool
29357 {
29359 }
29361 /* Make a "constrained auto" type-specifier. This is an auto or
29362 decltype(auto) type with constraints that must be associated after
29363 deduction. The constraint is formed from the given concept CON
29364 and its optional sequence of template arguments ARGS.
29366 TYPE must be the result of make_auto_type or make_decltype_auto_type. */
29368 static tree
29370 {
29371 /* Build the constraint. */
29383 /* Our canonical type depends on the constraint. */
29386 /* Attach the constraint to the type declaration. */
29388 }
29390 /* Make a "constrained auto" type-specifier. */
29392 tree
29394 {
29397 }
29399 /* Make a "constrained decltype(auto)" type-specifier. */
29401 tree
29403 {
29406 }
29408 /* Returns true if the placeholder type constraint T has any dependent
29409 (explicit) template arguments. */
29411 static bool
29413 {
29418 {
29421 }
29428 }
29430 /* Build and return a concept definition. Like other templates, the
29431 CONCEPT_DECL node is wrapped by a TEMPLATE_DECL. This returns the
29432 the TEMPLATE_DECL. */
29434 tree
29436 {
29442 /* A concept-definition shall not have associated constraints. */
29444 {
29447 }
29449 /* A concept-definition shall appear in namespace scope. Templates
29450 aren't allowed in block scope, so we only need to check for class
29451 scope. */
29453 {
29456 }
29459 {
29462 }
29464 /* Initially build the concept declaration; its type is bool. */
29474 /* Push the enclosing template. */
29476 }
29478 /* Given type ARG, return std::initializer_list<ARG>. */
29480 static tree
29482 {
29487 {
29491 "deducing from brace-enclosed initializer list"
29495 }
29501 }
29503 /* Replace auto in TYPE with std::initializer_list<auto>. */
29505 static tree
29507 {
29514 }
29516 /* Hash traits for hashing possibly constrained 'auto'
29517 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
29520 {
29523 };
29525 /* Hash the 'auto' T. */
29527 inline hashval_t
29529 {
29531 /* Matching constrained-type-specifiers denote the same template
29532 parameter, so hash the constraint. */
29534 else
29535 /* But unconstrained autos are all separate, so just hash the pointer. */
29537 }
29539 /* Compare two 'auto's. */
29543 {
29550 /* Two unconstrained autos are distinct. */
29555 }
29557 /* for_each_template_parm callback for extract_autos: if t is a (possibly
29558 constrained) auto, add it to the vector. */
29560 static int
29562 {
29565 {
29566 /* All the autos were built with index 0; fix that up now. */
29570 /* If this is a repeated constrained-type-specifier, use the index we
29571 chose before. */
29573 else
29574 {
29575 /* Otherwise this is new, so use the current count. */
29578 }
29580 {
29585 }
29586 }
29588 /* Always keep walking. */
29590 }
29592 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
29593 says they can appear anywhere in the type. */
29595 static tree
29597 {
29605 {
29609 }
29612 }
29614 /* The stem for deduction guide names. */
29617 /* Return the name for a deduction guide for class template TMPL. */
29619 tree
29621 {
29632 }
29634 /* True if NAME is the name of a deduction guide. */
29636 bool
29638 {
29642 }
29644 /* True if FN is a deduction guide. */
29646 bool
29648 {
29653 }
29655 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
29657 bool
29659 {
29666 }
29668 /* True if FN is a guide generated from a constructor template. */
29670 bool
29672 {
29680 }
29682 /* True if FN is an aggregate initialization guide or the copy deduction
29683 guide. */
29685 bool
29687 {
29691 /* Explicitly declared. */
29694 /* Derived from a constructor. */
29697 }
29699 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
29700 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
29701 template parameter types. Note that the handling of template template
29702 parameters relies on current_template_parms being set appropriately for the
29703 new template. */
29705 static tree
29708 {
29714 tree newtype;
29717 {
29721 }
29722 else
29723 {
29726 {
29727 // Substitute once to fix references to other template parameters.
29730 // Now substitute again to reduce the level of the auto.
29733 }
29734 else
29737 }
29739 tree newdecl
29744 tree newidx;
29747 {
29756 {
29757 tree newresult
29762 // First create a copy (ttargs) of tsubst_args with an
29763 // additional level for the template template parameter's own
29764 // template parameters (ttparms).
29765 tree ttparms = (INNERMOST_TEMPLATE_PARMS
29773 // Substitute ttargs into ttparms to fix references to
29774 // other template parameters.
29777 // Now substitute again with args based on tparms, to reduce
29778 // the level of the ttparms.
29781 complain);
29782 // Finally, tack the adjusted parms onto tparms.
29785 // As with all template template parms, the parameter list captured
29786 // by this template template parm that corresponds to its own level
29787 // should be empty. This avoids infinite recursion when structurally
29788 // comparing two such rewritten template template parms (PR102479).
29793 // All done.
29797 }
29801 else
29803 }
29804 else
29805 {
29807 tree newconst
29819 }
29822 }
29824 /* As rewrite_template_parm, but for the whole TREE_LIST representing a
29825 template parameter. */
29827 static tree
29830 {
29845 }
29847 /* Returns a C++17 class deduction guide template based on the constructor
29848 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
29849 guide, REFERENCE_TYPE for an implicit copy/move guide, or TREE_LIST for an
29850 aggregate initialization guide. OUTER_ARGS are the template arguments
29851 for the enclosing scope of the class. */
29853 static tree
29855 {
29859 location_t loc;
29863 {
29867 }
29870 {
29872 {
29876 else
29878 }
29881 else
29891 }
29892 else
29893 {
29899 fn_tmpl
29907 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
29908 fully specialized args for the enclosing class. Strip those off, as
29909 the deduction guide won't have those template parameters. */
29912 /* Discard the 'this' parameter. */
29920 {
29923 /* For a member template constructor, we need to flatten the two
29924 template parameter lists into one, and then adjust the function
29925 signature accordingly. This gets...complicated. */
29928 /* For a member template we should have two levels of parms/args, one
29929 for the class and one for the constructor. We stripped
29930 specialized args for further enclosing classes above. */
29934 /* Template args for translating references to the two-level template
29935 parameters into references to the one-level template parameters we
29936 are creating. */
29941 /* Template parms for the constructor template. */
29944 /* Template parms for the class template. */
29948 /* Template parms for the deduction guide start as a copy of the
29949 template parms for the class. We set current_template_parms for
29950 lookup_template_class_1. */
29956 /* Now we need to rewrite the constructor parms to append them to the
29957 class parms. */
29959 {
29963 tree newelt
29969 }
29971 /* Now we have a final set of template parms to substitute into the
29972 function signature. */
29979 {
29981 /* FIXME: We'd like to avoid substituting outer template
29982 arguments into the constraint ahead of time, but the
29983 construction of tsubst_args assumes that outer arguments
29984 are already substituted in. */
29987 }
29989 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped if
29990 cp_unevaluated_operand. */
29991 cp_evaluated ev;
29994 }
29995 else
29996 {
29997 /* Substitute in the same arguments to rewrite class members into
29998 references to members of an unknown specialization. */
29999 cp_evaluated ev;
30003 {
30005 /* FIXME: As above. */
30008 }
30009 }
30014 }
30017 {
30018 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
30022 }
30026 FUNCTION_DECL,
30041 }
30043 /* Add to LIST the member types for the reshaped initializer CTOR. */
30045 static tree
30047 {
30051 {
30055 {
30061 }
30065 /* Give the trailing pack expansion parameter a default argument to
30066 match aggregate initialization behavior, even if we deduce the
30067 length of the pack separately to more than we have initializers. */
30069 /* if ei is of array type and xi is a braced-init-list or string literal,
30070 Ti is an rvalue reference to the declared type of ei */
30075 {
30077 ftype = cp_build_qualified_type
30079 ftype = (cp_build_reference_type
30081 }
30083 }
30086 }
30088 /* Return whether ETYPE is, or is derived from, a specialization of TMPL. */
30090 static bool
30092 {
30098 tree tparms = (INNERMOST_TEMPLATE_PARMS
30105 }
30109 /* Return a C++20 aggregate deduction candidate for TYPE initialized from
30110 INIT. */
30112 static tree
30114 {
30122 {
30128 }
30130 /* We might be creating a guide for a class member template, e.g.,
30132 template<typename U> struct A {
30133 template<typename T> struct B { T t; };
30134 };
30136 At this point, A will have been instantiated. Below, we need to
30137 use both A<U>::B<T> (TEMPLATE_TYPE) and A<int>::B<T> (TYPE) types. */
30138 const bool member_template_p
30142 tree template_type = (member_template_p
30148 /* No aggregate candidate for copy-initialization. */
30150 {
30154 }
30156 /* If we encounter a problem, we just won't add the candidate. */
30161 {
30166 /* If we're creating a deduction guide for a member class template,
30167 we've used the original template pattern type for the reshape_init
30168 above; this is done because we want PARMS to be a template parameter
30169 type, something that can be deduced when used as a function template
30170 parameter. At this point the outer class template has already been
30171 partially instantiated (we deferred the deduction until the enclosing
30172 scope is non-dependent). Therefore we have to partially instantiate
30173 PARMS, so that its template level is properly reduced and we don't get
30174 mismatches when deducing types using the guide with PARMS. */
30176 {
30180 }
30181 }
30183 {
30186 len;
30188 {
30194 }
30195 }
30196 else
30197 /* Aggregate initialization doesn't apply to an initializer expression. */
30201 {
30207 }
30210 }
30212 /* UGUIDES are the deduction guides for the underlying template of alias
30213 template TMPL; adjust them to be deduction guides for TMPL. */
30215 static tree
30217 {
30218 /* [over.match.class.deduct]: When resolving a placeholder for a deduced
30219 class type (9.2.8.2) where the template-name names an alias template A,
30220 the defining-type-id of A must be of the form
30222 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
30224 as specified in 9.2.8.2. The guides of A are the set of functions or
30225 function templates formed as follows. For each function or function
30226 template f in the guides of the template named by the simple-template-id
30227 of the defining-type-id, the template arguments of the return type of f
30228 are deduced from the defining-type-id of A according to the process in
30229 13.10.2.5 with the exception that deduction does not fail if not all
30230 template arguments are deduced. Let g denote the result of substituting
30231 these deductions into f. If substitution succeeds, form a function or
30232 function template f' with the following properties and add it to the set
30233 of guides of A:
30235 * The function type of f' is the function type of g.
30237 * If f is a function template, f' is a function template whose template
30238 parameter list consists of all the template parameters of A (including
30239 their default template arguments) that appear in the above deductions or
30240 (recursively) in their default template arguments, followed by the
30241 template parameters of f that were not deduced (including their default
30242 template arguments), otherwise f' is not a function template.
30244 * The associated constraints (13.5.2) are the conjunction of the
30245 associated constraints of g and a constraint that is satisfied if and only
30246 if the arguments of A are deducible (see below) from the return type.
30248 * If f is a copy deduction candidate (12.4.1.8), then f' is considered to
30249 be so as well.
30251 * If f was generated from a deduction-guide (12.4.1.8), then f' is
30252 considered to be so as well.
30254 * The explicit-specifier of f' is the explicit-specifier of g (if
30255 any). */
30265 {
30272 {
30276 /* Deduce template arguments for f from the type-id of A. */
30282 /* CWG2664: Discard any deductions, still build the guide. */
30286 /* The number of parms for f' is the number of parms of A used in
30287 the deduced arguments plus non-deduced parms of f. */
30299 /* Set current_template_parms as in build_deduction_guide. */
30307 /* First copy over the used parms of A. */
30310 {
30313 {
30318 }
30319 }
30322 /* Adjust the deduced template args for f to refer to the A parms
30323 with their new indexes. */
30327 /* Now rewrite the non-deduced parms of f. */
30330 {
30337 }
30340 /* Substitute the deduced arguments plus the rewritten template
30341 parameters into f to get g. This covers the type, copyness,
30342 guideness, and explicit-specifier. */
30343 tree g;
30344 {
30345 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped
30346 if cp_unevaluated_operand. */
30347 cp_evaluated ev;
30349 }
30353 {
30354 /* The targs are all non-dependent, so g isn't a template. */
30358 }
30367 /* Substitute the associated constraints. */
30374 /* Add a constraint that the return type matches the instantiation of
30375 A with the same template arguments. */
30378 /* FIXME this should mean they don't compare as equivalent. */
30380 {
30383 }
30386 {
30389 }
30390 }
30391 else
30392 {
30393 /* For a non-template deduction guide, if the arguments of A aren't
30394 deducible from the return type, don't add the candidate. */
30395 non_template:
30398 }
30401 }
30404 }
30406 /* True iff template arguments for TMPL can be deduced from TYPE.
30407 Used to implement CPTK_IS_DEDUCIBLE for alias CTAD according to
30408 [over.match.class.deduct].
30410 This check is specified in terms of partial specialization, so the behavior
30411 should be parallel to that of get_partial_spec_bindings. */
30413 bool
30415 {
30421 /* If tmpl is a class template, this is trivial: it's deducible if TYPE is a
30422 specialization of TMPL. */
30428 /* Otherwise it's an alias template. */
30429 again:
30434 /* We don't fail on an undeduced targ the second time through (like
30435 get_partial_spec_bindings) because we're going to try defaults. */
30438 {
30444 {
30449 }
30450 /* If the type parameter is a parameter pack, then it will be deduced
30451 to an empty parameter pack. This is another case that doesn't model
30452 well as partial specialization. */
30454 {
30455 tree arg;
30457 {
30460 }
30461 else
30465 }
30466 }
30468 /* Maybe add in default template args. This seems like a flaw in the
30469 specification in terms of partial specialization, since it says the
30470 partial specialization has the the template parameter list of A, but a
30471 partial specialization can't have default targs. */
30476 /* I believe we don't need the template_template_parm_bindings_ok_p call
30477 because coerce_template_parms did coerce_template_template_parms. */
30480 }
30482 /* Return artificial deduction guides built from the constructors of class
30483 template TMPL. */
30485 static tree
30487 {
30494 {
30495 /* Skip inherited constructors. */
30501 }
30503 /* Add implicit default constructor deduction guide. */
30505 {
30507 complain);
30509 }
30511 /* Add copy guide. */
30512 {
30515 complain);
30517 }
30520 }
30524 /* Return the non-aggregate deduction guides for deducible template TMPL. The
30525 aggregate candidate is added separately because it depends on the
30526 initializer. Set ANY_DGUIDES_P if we find a non-implicit deduction
30527 guide. */
30529 static tree
30531 {
30534 {
30538 complain);
30539 }
30540 else
30541 {
30547 else
30549 }
30551 /* Cache the deduction guides for a template. We also remember the result of
30552 lookup, and rebuild everything if it changes; should be very rare. */
30556 {
30560 }
30561 else
30562 {
30565 }
30570 else
30571 {
30575 }
30579 }
30581 /* Return whether TMPL is a (class template argument-) deducible template. */
30583 bool
30585 {
30586 /* A deducible template is either a class template or is an alias template
30587 whose defining-type-id is of the form
30589 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
30591 where the nested-name-specifier (if any) is non-dependent and the
30592 template-name of the simple-template-id names a deducible template. */
30603 }
30605 /* Deduce template arguments for the class template placeholder PTYPE for
30606 template TMPL based on the initializer INIT, and return the resulting
30607 type. */
30609 static tree
30612 {
30613 /* We should have handled this in the caller. */
30617 /* If the class was erroneous, don't try to deduce, because that
30618 can generate a lot of diagnostic. */
30624 /* Wait until the enclosing scope is non-dependent. */
30629 /* Initializing one placeholder from another. */
30640 {
30644 }
30646 {
30648 {
30649 /* Be permissive with equivalent alias templates. */
30652 bool complained
30654 "alias template deduction only available "
30659 {
30662 }
30663 }
30664 else
30666 }
30668 /* Wait until the initializer is non-dependent. */
30672 /* Don't bother with the alias rules for an equivalent template. */
30685 {
30690 {
30691 /* As an exception, the first phase in 16.3.1.7 (considering the
30692 initializer list as a single argument) is omitted if the
30693 initializer list consists of a single expression of type cv U,
30694 where U is a specialization of C or a class derived from a
30695 specialization of C. */
30699 }
30702 else
30704 }
30707 else
30710 /* Do this now to avoid problems with erroneous args later on. */
30720 /* Prune explicit deduction guides in copy-initialization context (but
30721 not copy-list-initialization). */
30724 {
30730 {
30731 /* Found a nonconverting guide, prune the candidates. */
30738 }
30739 }
30747 /* If this is list-initialization and the class has a list guide, first
30748 try deducing from the list as a single argument, as [over.match.list]. */
30750 {
30758 {
30759 /* That didn't work, now try treating the list as a sequence of
30760 arguments. */
30766 }
30767 }
30770 {
30772 " of %qT, as it has no non-explicit deduction guides or "
30775 }
30777 {
30781 }
30787 {
30789 {
30795 }
30797 }
30798 /* [over.match.list]/1: In copy-list-initialization, if an explicit
30799 constructor is chosen, the initialization is ill-formed. */
30801 {
30803 {
30805 {
30806 // TODO: Pass down location from cp_finish_decl.
30808 "explicit deduction guide selected in "
30813 }
30815 }
30816 }
30818 /* If CTAD succeeded but the type doesn't have any explicit deduction
30819 guides, this deduction might not be what the user intended. */
30821 {
30825 "%qT may not intend to support class template argument "
30829 }
30833 }
30835 /* Return true if INIT is an unparenthesized id-expression or an
30836 unparenthesized class member access. Used for the argument of
30837 decltype(auto). */
30839 bool
30841 {
30844 /* We need to be able to tell '(r)' and 'r' apart (when it's of
30845 reference type). Only the latter is an id-expression. */
30853 }
30855 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
30856 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
30857 The CONTEXT determines the context in which auto deduction is performed
30858 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
30860 OUTER_TARGS is used during template argument deduction (context == adc_unify)
30861 to properly substitute the result. It's also used in the adc_unify and
30862 adc_requirement contexts to communicate the necessary template arguments
30863 to satisfaction. OUTER_TARGS is ignored in other contexts.
30865 Additionally for adc_unify contexts TMPL is the template for which TYPE
30866 is a template parameter type.
30868 For partial-concept-ids, extra args from OUTER_TARGS, TMPL and the current
30869 scope may be appended to the list of deduced template arguments prior to
30870 determining constraint satisfaction as appropriate. */
30872 tree
30879 {
30885 /* Defining a subset of type-dependent expressions that we can deduce
30886 from ahead of time isn't worth the trouble. */
30889 /* Similarly, we can't deduce from another undeduced decl. */
30893 /* We may be doing a partial substitution, but we still want to replace
30894 auto_node. */
30898 {
30899 /* We don't recurse here because we can't deduce from a nested
30900 initializer_list. */
30904 }
30908 /* In C++23, we must deduce the type to int&& for code like
30909 decltype(auto) f(int&& x) { return (x); }
30910 or
30911 auto&& f(int x) { return x; }
30912 so we use treat_lvalue_as_rvalue_p. But don't do it for
30913 decltype(auto) f(int x) { return x; }
30914 where we should deduce 'int' rather than 'int&&'; transmogrifying
30915 INIT to an rvalue would break that. */
30916 tree r;
30926 /* C++17 class template argument deduction. */
30930 /* Nothing we can do with this, even in deduction context. */
30935 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
30936 with either a new invented type template parameter U or, if the
30937 initializer is a braced-init-list (8.5.4), with
30938 std::initializer_list<U>. */
30940 {
30945 else
30946 {
30948 {
30952 "for deduction to %<std::initializer_list%>, use copy-"
30954 }
30956 }
30957 }
30962 tree targs;
30966 {
30967 /* [dcl.struct.bind]/1 - if decomposition declaration has no ref-qualifiers
30968 and initializer has array type, deduce cv-qualified array type. */
30971 }
30973 {
30981 }
30982 else
30983 {
30988 tree tparms;
30992 else
30993 {
30997 }
31001 DEDUCE_CALL,
31004 {
31006 /* Try again at instantiation time. */
31010 /* If type is error_mark_node a diagnostic must have been
31011 emitted by now. Also, having a mention to '<type error>'
31012 in the diagnostic is not really useful to the user. */
31013 {
31016 && (auto_node
31020 init);
31021 else
31024 DEDUCE_CALL,
31026 }
31028 }
31029 }
31031 /* Check any placeholder constraints against the deduced type. */
31035 {
31037 {
31042 /* If the constraint is dependent, we need to wait until
31043 instantiation time to resolve the placeholder. */
31046 }
31053 {
31057 {
31058 /* As in satisfy_declaration_constraints. */
31062 else
31064 }
31065 }
31072 /* HACK: Compensate for callers not always communicating all levels of
31073 outer template arguments by filling in the outermost missing levels
31074 with dummy levels before checking satisfaction. We'll still crash
31075 if the constraint depends on a template argument belonging to one of
31076 these missing levels, but this hack otherwise allows us to handle a
31077 large subset of possible constraints (including all non-dependent
31078 constraints). */
31081 {
31086 }
31089 {
31091 {
31092 auto_diagnostic_group d;
31094 {
31112 }
31114 }
31116 }
31117 }
31120 /* The outer template arguments are already substituted into type
31127 }
31129 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
31130 result. */
31132 tree
31134 {
31136 {
31139 }
31143 {
31144 /* In an abbreviated function template we didn't know we were dealing
31145 with a function template when we saw the auto return type, so rebuild
31146 the return type using an auto with the correct level. */
31151 auto_vec);
31152 /* Also rebuild the constraint info in terms of the new auto. */
31160 }
31162 }
31164 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
31165 'decltype(auto)' or a deduced class template. */
31167 bool
31169 {
31174 else
31176 }
31178 /* for_each_template_parm callback for type_uses_auto. */
31180 int
31182 {
31184 }
31186 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
31187 a use of `auto'. Returns NULL_TREE otherwise. */
31189 tree
31191 {
31195 /* For parameter packs, check the contents of the pack. */
31200 {
31201 /* The Concepts TS allows multiple autos in one type-specifier; just
31202 return the first one we find, do_auto_deduction will collect all of
31203 them. */
31207 else
31209 }
31210 else
31212 }
31214 /* Report ill-formed occurrences of auto types in ARGUMENTS. If
31215 concepts are enabled, auto is acceptable in template arguments, but
31216 only when TEMPL identifies a template class. Return TRUE if any
31217 such errors were reported. */
31219 bool
31221 {
31223 /* Only the concepts TS allows 'auto' as a type-id; it'd otherwise
31224 have already been rejected by the parser more generally. */
31227 /* If there were previous errors, nevermind. */
31231 /* If TMPL is an identifier, we're parsing and we can't tell yet
31232 whether TMPL is supposed to be a type, a function or a variable.
31233 We'll only be able to tell during template substitution, so we
31234 expect to be called again then. If concepts are enabled and we
31235 know we have a type, we're ok. */
31242 /* Quickly search for any occurrences of auto; usually there won't
31243 be any, and then we'll avoid allocating the vector. */
31251 {
31256 }
31259 }
31261 /* Recursively walk over && expressions searching for EXPR. Return a reference
31262 to that expression. */
31265 {
31269 {
31274 }
31276 }
31278 /* Convert the generic type parameters in PARM that match the types given in the
31279 range [START_IDX, END_IDX) from the current_template_parms into generic type
31280 packs. */
31282 tree
31284 {
31295 {
31296 /* Create a distinct parameter pack type from the current parm and add it
31297 to the replacement args to tsubst below into the generic function
31298 parameter. */
31312 /* Replace the current template parameter with new pack. */
31315 /* Surgically adjust the associated constraint of adjusted parameter
31316 and it's corresponding contribution to the current template
31317 requirements. */
31319 {
31325 /* If there was a constraint, we also need to replace that in
31326 the template requirements, which we've already built. */
31330 }
31331 }
31337 /* If there are more levels then build up the replacement with the outer
31338 template parms. */
31342 replacement);
31345 }
31347 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
31348 0..N-1. */
31350 void
31352 {
31355 integer_type_node,
31356 NULL_TREE),
31360 CP_BUILT_IN_INTEGER_PACK);
31361 }
31363 /* Walk the decl or type specialization table calling FN on each
31364 entry. */
31366 void
31370 {
31376 }
31378 /* Lookup the specialization of *ELT, in the decl or type
31379 specialization table. Return the SPEC that's already there, or
31380 NULL if nothing. */
31382 tree
31384 {
31394 }
31396 /* Return flags encoding whether SPEC is on the instantiation and/or
31397 specialization lists of TMPL. */
31399 unsigned
31401 {
31407 {
31410 }
31415 /* Only need to search if DECL is a partial specialization. */
31419 {
31422 }
31425 }
31427 /* Add a new specialization described by SPEC. DECL is the
31428 maybe-template decl and FLAGS is as returned from
31429 get_mergeable_specialization_flags. */
31431 void
31434 {
31437 {
31446 {
31449 }
31450 }
31453 {
31456 /* We don't distinguish different constrained partial type
31457 specializations, so there could be duplicates. Everything else
31458 must be new. */
31460 {
31466 }
31467 }
31474 {
31475 /* A partial specialization. */
31480 }
31481 }
31483 /* Set up the hash tables for template instantiations. */
31485 void
31487 {
31493 }
31495 /* Print stats about the template hash tables for -fstats. */
31497 void
31499 {
31508 }
31510 #if CHECKING_P
31514 /* Verify that build_non_dependent_expr () works, for various expressions,
31515 and that location wrappers don't affect the results. */
31517 static void
31519 {
31522 /* Verify constants, without and with location wrappers. */
31539 }
31541 /* Verify that type_dependent_expression_p () works correctly, even
31542 in the presence of location wrapper nodes. */
31544 static void
31546 {
31551 /* If no templates are involved, nothing is type-dependent. */
31557 /* Within a template, an unresolved name is always type-dependent. */
31560 /* Ensure it copes with NULL_TREE and errors. */
31564 /* A USING_DECL in a template should be type-dependent, even if wrapped
31565 with a location wrapper (PR c++/83799). */
31574 }
31576 /* Run all of the selftests within this file. */
31578 void
31580 {
31583 }