| blob | 21b08a6266a57268e5d1eb13c6798697467e133e |
1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2023 Free Software Foundation, Inc.
3 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
4 Rewritten by Jason Merrill (jason@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Known bugs or deficiencies include:
24 all methods must be provided in header files; can't use a source
25 file that contains only the method templates and "just win".
27 Fixed by: C++20 modules. */
50 /* The type of functions taking a tree, and some additional data, and
51 returning an int. */
54 /* The PENDING_TEMPLATES is a list of templates whose instantiations
55 have been deferred, either because their definitions were not yet
56 available, or because we were putting off doing the work. */
58 {
61 };
75 /* Live only within one (recursive) call to tsubst_expr. We use
76 this to pass the statement expression node from the STMT_EXPR
77 to the EXPR_STMT that is its result. */
80 // -------------------------------------------------------------------------- //
81 // Local Specialization Stack
82 //
83 // Implementation of the RAII helper for creating new local
84 // specializations.
87 {
89 ;
92 else
94 }
97 {
99 {
102 }
103 }
105 /* True if we've recursed into fn_type_unification too many times. */
109 {
113 };
115 /* The general template is not in these tables. */
120 /* Contains canonical template parameter types. The vector is indexed by
121 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
122 TREE_LIST, whose TREE_VALUEs contain the canonical template
123 parameters of various types and levels. */
126 #define UNIFY_ALLOW_NONE 0
127 #define UNIFY_ALLOW_MORE_CV_QUAL 1
128 #define UNIFY_ALLOW_LESS_CV_QUAL 2
129 #define UNIFY_ALLOW_DERIVED 4
130 #define UNIFY_ALLOW_INTEGER 8
131 #define UNIFY_ALLOW_OUTER_LEVEL 16
132 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
133 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
136 tbr_incomplete_type,
137 tbr_ambiguous_baseclass,
138 tbr_success
139 };
225 /* Make the current scope suitable for access checking when we are
226 processing T. T can be FUNCTION_DECL for instantiated function
227 template, VAR_DECL for static member variable, or TYPE_DECL for
228 for a class or alias template (needed by instantiate_decl). */
230 void
232 {
244 /* An artificial deduction guide should have the same access as
245 the constructor. */
247 else
251 {
254 }
255 }
257 /* Restore the scope set up by push_access_scope. T is the node we
258 are processing. */
260 void
262 {
272 else
274 }
276 /* Do any processing required when DECL (a member template
277 declaration) is finished. Returns the TEMPLATE_DECL corresponding
278 to DECL, unless it is a specialization, in which case the DECL
279 itself is returned. */
281 tree
283 {
290 {
291 tree type;
299 {
303 }
305 }
310 {
312 {
315 }
316 else
318 }
319 else
324 }
326 /* Create a template info node. */
328 tree
330 {
335 }
337 /* Return the template info node corresponding to T, whatever T is. */
339 tree
341 {
363 }
365 /* Returns the template nesting level of the indicated class TYPE.
367 For example, in:
368 template <class T>
369 struct A
370 {
371 template <class U>
372 struct B {};
373 };
375 A<T>::B<U> has depth two, while A<T> has depth one.
376 Both A<T>::B<int> and A<int>::B<U> have depth one, if
377 they are instantiations, not specializations.
379 This function is guaranteed to return 0 if passed NULL_TREE so
380 that, for example, `template_class_depth (current_class_type)' is
381 always safe. */
383 int
385 {
389 {
399 {
402 else
404 }
407 else
409 }
412 }
414 /* Return TRUE if NODE instantiates a template that has arguments of
415 its own, be it directly a primary template or indirectly through a
416 partial specializations. */
417 static bool
419 {
431 /* So now we know we have a specialization, but it could be a full
432 or a partial specialization. To tell which, compare the depth of
433 its template arguments with those of its context. */
442 }
444 /* Subroutine of maybe_begin_member_template_processing.
445 Returns true if processing DECL needs us to push template parms. */
447 static bool
449 {
455 }
457 /* Subroutine of maybe_begin_member_template_processing.
458 Push the template parms in PARMS, starting from LEVELS steps into the
459 chain, and ending at the beginning, since template parms are listed
460 innermost first. */
462 static void
464 {
472 current_template_parms
480 NULL);
482 {
491 {
498 /* Push the CONST_DECL. */
504 }
505 }
506 }
508 /* Restore the template parameter context for a member template, a
509 friend template defined in a class definition, or a non-template
510 member of template class. */
512 void
514 {
515 tree parms;
520 {
523 /* Disregard full specializations (c++/60999). */
526 }
529 {
534 {
537 }
540 }
542 /* Remember how many levels of template parameters we pushed so that
543 we can pop them later. */
545 }
547 /* Undo the effects of maybe_begin_member_template_processing. */
549 void
551 {
560 {
564 }
565 }
567 /* Return a new template argument vector which contains all of ARGS,
568 but has as its innermost set of arguments the EXTRA_ARGS. */
570 tree
572 {
573 tree new_args;
591 }
593 /* Like add_to_template_args, but only the outermost ARGS are added to
594 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
595 (EXTRA_ARGS) levels are added. This function is used to combine
596 the template arguments from a partial instantiation with the
597 template arguments used to attain the full instantiation from the
598 partial instantiation.
600 If ARGS is a TEMPLATE_DECL, use its parameters as args. */
602 tree
604 {
605 tree new_args;
610 {
613 }
615 /* If there are more levels of EXTRA_ARGS than there are ARGS,
616 something very fishy is going on. */
619 /* If *all* the new arguments will be the EXTRA_ARGS, just return
620 them. */
624 /* For the moment, we make ARGS look like it contains fewer levels. */
629 /* Now, we restore ARGS to its full dimensions. */
633 }
635 /* Return the N levels of innermost template arguments from the ARGS. */
637 tree
639 {
640 tree new_args;
646 /* If N is 1, just return the innermost set of template arguments. */
650 /* If we're not removing anything, just return the arguments we were
651 given. */
657 /* Make a new set of arguments, not containing the outer arguments. */
664 }
666 /* The inverse of get_innermost_template_args: Return all but the innermost
667 EXTRA_LEVELS levels of template arguments from the ARGS. */
669 static tree
671 {
672 tree new_args;
678 /* If N is 1, just return the outermost set of template arguments. */
682 /* If we're not removing anything, just return the arguments we were
683 given. */
688 /* Make a new set of arguments, not containing the inner arguments. */
695 }
697 /* We've got a template header coming up; push to a new level for storing
698 the parms. */
700 void
702 {
703 /* We use a non-tag-transparent scope here, which causes pushtag to
704 put tags in this scope, rather than in the enclosing class or
705 namespace scope. This is the right thing, since we want
706 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
707 global template class, push_template_decl handles putting the
708 TEMPLATE_DECL into top-level scope. For a nested template class,
709 e.g.:
711 template <class T> struct S1 {
712 template <class T> struct S2 {};
713 };
715 pushtag contains special code to insert the TEMPLATE_DECL for S2
716 at the right scope. */
722 /* Add a dummy parameter level while we process the parameter list. */
723 current_template_parms
726 current_template_parms);
727 }
729 /* This routine is called when a specialization is declared. If it is
730 invalid to declare a specialization here, an error is reported and
731 false is returned, otherwise this routine will return true. */
733 static bool
735 {
738 /* [temp.expl.spec]
740 An explicit specialization shall be declared in the namespace of
741 which the template is a member, or, for member templates, in the
742 namespace of which the enclosing class or enclosing class
743 template is a member. An explicit specialization of a member
744 function, member class or static data member of a class template
745 shall be declared in the namespace of which the class template
746 is a member. */
748 {
751 }
753 /* [temp.expl.spec]
755 In an explicit specialization declaration for a member of a class
756 template or a member template that appears in namespace scope,
757 the member template and some of its enclosing class templates may
758 remain unspecialized, except that the declaration shall not
759 explicitly specialize a class member template if its enclosing
760 class templates are not explicitly specialized as well. */
762 {
765 }
768 }
770 /* We've just seen template <>. */
772 bool
774 {
778 }
780 /* Called at then end of processing a declaration preceded by
781 template<>. */
783 void
785 {
788 }
790 /* Any template <>'s that we have seen thus far are not referring to a
791 function specialization. */
793 void
795 {
798 }
800 /* We've just seen a template header. If SPECIALIZATION is nonzero,
801 it was of the form template <>. */
803 static void
805 {
807 template_header_count++;
808 }
810 /* We're beginning an explicit instantiation. */
812 void
814 {
817 }
820 void
822 {
825 }
827 /* An explicit specialization or partial specialization of TMPL is being
828 declared. Check that the namespace in which the specialization is
829 occurring is permissible. Returns false iff it is invalid to
830 specialize TMPL in the current namespace. */
832 static bool
834 {
837 /* [tmpl.expl.spec]
839 An explicit specialization shall be declared in a namespace enclosing the
840 specialized template. An explicit specialization whose declarator-id is
841 not qualified shall be declared in the nearest enclosing namespace of the
842 template, or, if the namespace is inline (7.3.1), any namespace from its
843 enclosing namespace set. */
846 {
849 }
852 /* Same or enclosing namespace. */
854 else
855 {
856 auto_diagnostic_group d;
862 }
863 }
865 /* SPEC is an explicit instantiation. Check that it is valid to
866 perform this explicit instantiation in the current namespace. */
868 static void
870 {
871 tree ns;
873 /* DR 275: An explicit instantiation shall appear in an enclosing
874 namespace of its template. */
880 }
882 /* Returns true if TYPE is a new partial specialization that needs to be
883 set up. This may also modify TYPE to point to the correct (new or
884 existing) constrained partial specialization. */
886 static bool
888 {
889 /* An implicit instantiation of an incomplete type implies
890 the definition of a new class template.
892 template<typename T>
893 struct S;
895 template<typename T>
896 struct S<T*>;
898 Here, S<T*> is an implicit instantiation of S whose type
899 is incomplete. */
903 /* It can also be the case that TYPE is a completed specialization.
904 Continuing the previous example, suppose we also declare:
906 template<typename T>
907 requires Integral<T>
908 struct S<T*>;
910 Here, S<T*> refers to the specialization S<T*> defined
911 above. However, we need to differentiate definitions because
912 we intend to define a new partial specialization. In this case,
913 we rely on the fact that the constraints are different for
914 this declaration than that above.
916 Note that we also get here for injected class names and
917 late-parsed template definitions. We must ensure that we
918 do not create new type declarations for those cases. */
920 {
924 /* If there are no template parameters, this cannot be a new
925 partial template specialization? */
929 /* The injected-class-name is not a new partial specialization. */
933 /* If the constraints are not the same as those of the primary
934 then, we can probably create a new specialization. */
938 {
942 }
944 /* Also, if there's a pre-existing specialization with matching
945 constraints, then this also isn't new. */
948 {
954 {
957 }
959 }
961 /* Create a new type node (and corresponding type decl)
962 for the newly declared specialization. */
967 /* We only need a separate type node for storing the definition of this
968 partial specialization; uses of S<T*> are unconstrained, so all are
969 equivalent. So keep TYPE_CANONICAL the same. */
972 /* Build the corresponding type decl. */
984 }
987 }
989 /* The TYPE is being declared. If it is a template type, that means it
990 is a partial specialization. Do appropriate error-checking. */
992 tree
994 {
995 tree context;
1000 /* A lambda that appears in specialization context is not itself a
1001 specialization. */
1005 /* An injected-class-name is not a specialization. */
1010 {
1014 }
1019 {
1025 else
1028 }
1030 {
1031 /* This is for ordinary explicit specialization and partial
1032 specialization of a template class such as:
1034 template <> class C<int>;
1036 or:
1038 template <class T> class C<T*>;
1040 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
1043 {
1050 {
1055 }
1056 }
1062 /* Trying to define a specialization either without a template<> header
1063 or in an inappropriate place. We've already given an error, so just
1064 bail now so we don't actually define the specialization. */
1066 }
1072 {
1073 /* This is for an explicit specialization of member class
1074 template according to [temp.expl.spec/18]:
1076 template <> template <class U> class C<int>::D;
1078 The context `C<int>' must be an implicit instantiation.
1079 Otherwise this is just a member class template declared
1080 earlier like:
1082 template <> class C<int> { template <class U> class D; };
1083 template <> template <class U> class C<int>::D;
1085 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1086 while in the second case, `C<int>::D' is a primary template
1087 and `C<T>::D' may not exist. */
1091 {
1092 tree t;
1097 {
1100 type))
1103 }
1105 /* Check for invalid specialization after instantiation:
1107 template <> template <> class C<int>::D<int>;
1108 template <> template <class U> class C<int>::D; */
1112 {
1116 {
1117 /* We already have a full specialization of this partial
1118 instantiation, or a full specialization has been
1119 looked up but not instantiated. Reassign it to the
1120 new member specialization template. */
1121 spec_entry elt;
1134 spec_entry **slot
1139 }
1140 else
1141 /* But if we've had an implicit instantiation, that's a
1142 problem ([temp.expl.spec]/6). */
1145 }
1147 /* Mark TYPE as a specialization. And as a result, we only
1148 have one level of template argument for the innermost
1149 class template. */
1154 }
1155 }
1157 {
1158 /* Someday C++0x may allow for enum template specialization. */
1163 else
1164 {
1167 }
1168 }
1171 }
1173 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1174 gone through coerce_template_parms by now. */
1176 static void
1178 {
1180 {
1189 /* Allow typedefs on the type of a non-type argument, since a
1191 else
1193 }
1194 }
1196 static void
1198 {
1203 }
1205 /* Retrieve the specialization (in the sense of [temp.spec] - a
1206 specialization is either an instantiation or an explicit
1207 specialization) of TMPL for the given template ARGS. If there is
1208 no such specialization, return NULL_TREE. The ARGS are a vector of
1209 arguments, or a vector of vectors of arguments, in the case of
1210 templates with more than one level of parameters.
1212 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1213 then we search for a partial specialization matching ARGS. This
1214 parameter is ignored if TMPL is not a class template.
1216 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1217 result is a NONTYPE_ARGUMENT_PACK. */
1219 static tree
1221 {
1231 /* There should be as many levels of arguments as there are
1232 levels of parameters. */
1241 /* Lambda functions in templates aren't instantiated normally, but through
1242 tsubst_lambda_expr. */
1246 spec_entry elt;
1254 else
1263 }
1265 /* Like retrieve_specialization, but for local declarations. */
1267 tree
1269 {
1275 }
1277 /* Returns nonzero iff DECL is a specialization of TMPL. */
1279 int
1281 {
1282 tree t;
1285 {
1291 }
1292 else
1293 {
1302 }
1305 }
1307 /* Returns nonzero iff DECL is a specialization of friend declaration
1308 FRIEND_DECL according to [temp.friend]. */
1310 bool
1312 {
1319 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1320 of a template class, we want to check if DECL is a specialization
1321 if this. */
1326 {
1327 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1330 }
1335 /* There is nothing to do if this is not a template friend. */
1342 /* [temp.friend/6]
1343 A member of a class template may be declared to be a friend of a
1344 non-template class. In this case, the corresponding member of
1345 every specialization of the class template is a friend of the
1346 class granting friendship.
1348 For example, given a template friend declaration
1350 template <class T> friend void A<T>::f();
1352 the member function below is considered a friend
1354 template <> struct A<int> {
1355 void f();
1356 };
1358 For this type of template friend, TEMPLATE_DEPTH below will be
1359 nonzero. To determine if DECL is a friend of FRIEND, we first
1360 check if the enclosing class is a specialization of another. */
1367 {
1368 /* Next, we check the members themselves. In order to handle
1369 a few tricky cases, such as when FRIEND_DECL's are
1371 template <class T> friend void A<T>::g(T t);
1372 template <class T> template <T t> friend void A<T>::h();
1374 and DECL's are
1376 void A<int>::g(int);
1377 template <int> void A<int>::h();
1379 we need to figure out ARGS, the template arguments from
1380 the context of DECL. This is required for template substitution
1381 of `T' in the function parameter of `g' and template parameter
1382 of `h' in the above examples. Here ARGS corresponds to `int'. */
1389 {
1391 {
1394 else
1396 current_depth++;
1397 }
1399 }
1402 {
1404 tree friend_type;
1405 tree decl_type;
1406 tree friend_args_type;
1407 tree decl_args_type;
1409 /* Make sure that both DECL and FRIEND_DECL are templates or
1410 non-templates. */
1416 {
1417 /* If both are templates, check template parameter list. */
1418 tree friend_parms
1423 friend_parms))
1427 }
1428 else
1436 /* Check if return types match. */
1440 /* Check if function parameter types match, ignoring the
1441 `this' parameter. */
1450 }
1451 else
1452 {
1453 /* DECL is a TYPE_DECL */
1457 /* Make sure that both DECL and FRIEND_DECL are templates or
1458 non-templates. */
1459 is_template
1466 {
1467 tree friend_parms;
1468 /* If both are templates, check the name of the two
1469 TEMPLATE_DECL's first because is_friend didn't. */
1474 /* Now check template parameter list. */
1475 friend_parms
1478 return comp_template_parms
1480 friend_parms);
1481 }
1482 else
1485 }
1486 }
1488 }
1490 /* Register the specialization SPEC as a specialization of TMPL with
1491 the indicated ARGS. IS_FRIEND indicates whether the specialization
1492 is actually just a friend declaration. ATTRLIST is the list of
1493 attributes that the specialization is declared with or NULL when
1494 it isn't. Returns SPEC, or an equivalent prior declaration, if
1495 available.
1497 We also store instantiations of field packs in the hash table, even
1498 though they are not themselves templates, to make lookup easier. */
1500 static tree
1502 hashval_t hash)
1503 {
1504 tree fn;
1512 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1513 register it; we want the corresponding TEMPLATE_DECL instead.
1514 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1515 the more obvious `uses_template_parms (spec)' to avoid problems
1516 with default function arguments. In particular, given
1517 something like this:
1519 template <class T> void f(T t1, T t = T())
1521 the default argument expression is not substituted for in an
1522 instantiation unless and until it is actually needed. */
1525 spec_entry elt;
1536 else
1539 /* We can sometimes try to re-register a specialization that we've
1540 already got. In particular, regenerate_decl_from_template calls
1541 duplicate_decls which will update the specialization list. But,
1542 we'll still get called again here anyhow. It's more convenient
1543 to simply allow this than to try to prevent it. */
1547 {
1549 {
1552 {
1554 fn);
1556 }
1557 else
1558 {
1559 tree clone;
1560 /* This situation should occur only if the first
1561 specialization is an implicit instantiation, the
1562 second is an explicit specialization, and the
1563 implicit instantiation has not yet been used. That
1564 situation can occur if we have implicitly
1565 instantiated a member function and then specialized
1566 it later.
1568 We can also wind up here if a friend declaration that
1569 looked like an instantiation turns out to be a
1570 specialization:
1572 template <class T> void foo(T);
1573 class S { friend void foo<>(int) };
1574 template <> void foo(int);
1576 We transform the existing DECL in place so that any
1577 pointers to it become pointers to the updated
1578 declaration.
1580 If there was a definition for the template, but not
1581 for the specialization, we want this to look as if
1582 there were no definition, and vice versa. */
1586 /* The call to duplicate_decls will have applied
1587 [temp.expl.spec]:
1589 An explicit specialization of a function template
1590 is inline only if it is explicitly declared to be,
1591 and independently of whether its function template
1592 is.
1594 to the primary function; now copy the inline bits to
1595 the various clones. */
1597 {
1604 }
1608 }
1609 }
1611 {
1614 /* We've already complained in duplicate_decls. */
1618 /* Dup decl failed, but this is a new definition. Set the
1619 line number so any errors match this new
1620 definition. */
1624 }
1625 }
1629 /* A specialization must be declared in the same namespace as the
1630 template it is specializing. */
1643 /* If TMPL is a forward declaration of a template function, keep a list
1644 of all specializations in case we need to reassign them to a friend
1645 template later in tsubst_friend_function.
1647 Also keep a list of all variable template instantiations so that
1648 process_partial_specialization can check whether a later partial
1649 specialization would have used it. */
1654 }
1656 /* Restricts tree and type comparisons. */
1660 /* Returns true iff two spec_entry nodes are equivalent. */
1662 bool
1664 {
1673 /* tmpl could be a FIELD_DECL for a capture pack. */
1677 {
1678 /* Partial specializations of a variable template can be distinguished by
1679 constraints. */
1683 }
1689 }
1691 /* Returns a hash for a template TMPL and template arguments ARGS. */
1693 static hashval_t
1695 {
1698 }
1700 hashval_t
1702 {
1707 }
1709 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1710 ignoring SPEC. */
1712 hashval_t
1714 {
1716 }
1718 /* Recursively calculate a hash value for a template argument ARG, for use
1719 in the hash tables of template specializations. We must be
1720 careful to (at least) skip the same entities template_args_equal
1721 does. */
1723 hashval_t
1725 {
1730 /* Strip nop-like things, but not the same as STRIP_NOPS. */
1741 {
1743 /* Getting here with an ARGUMENT_PACK_SELECT means we're probably
1744 preserving it in a hash table, which is bad because it will change
1745 meaning when gen_elem_of_pack_expansion_instantiation changes the
1746 ARGUMENT_PACK_SELECT_INDEX. */
1780 {
1783 {
1786 }
1788 }
1792 {
1795 }
1806 val = iterative_hash_template_arg
1818 val);
1820 val);
1829 /* [temp.over.link] Two lambda-expressions are never considered
1830 equivalent.
1832 So just hash the closure type. */
1843 /* Now hash operands as usual. */
1847 {
1850 {
1854 }
1856 call_expr_arg_iterator ai;
1861 }
1865 }
1869 {
1872 {
1873 // We want an alias specialization that survived strip_typedefs
1874 // to hash differently from its TYPE_CANONICAL, to avoid hash
1875 // collisions that compare as different in template_args_equal.
1876 // These could be dependent specializations that strip_typedefs
1877 // left alone, or untouched specializations because
1878 // coerce_template_parms returns the unconverted template
1879 // arguments if it sees incomplete argument packs.
1882 }
1885 {
1892 {
1893 /* Hash the components that are relevant to TYPENAME_TYPE
1894 equivalence as determined by structural_comptypes. We
1895 can only coherently do this when comparing_specializations
1896 is set, because otherwise structural_comptypes tries
1897 resolving TYPENAME_TYPE via the current instantiation. */
1902 }
1909 }
1922 }
1923 }
1925 /* Unregister the specialization SPEC as a specialization of TMPL.
1926 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1927 if the SPEC was listed as a specialization of TMPL.
1929 Note that SPEC has been ggc_freed, so we can't look inside it. */
1931 bool
1933 {
1935 spec_entry elt;
1943 {
1948 }
1951 }
1953 /* Like register_specialization, but for local declarations. We are
1954 registering SPEC, an instantiation of TMPL. */
1956 void
1958 {
1961 }
1963 /* Registers T as a specialization of itself. This is used to preserve
1964 the references to already-parsed parameters when instantiating
1965 postconditions. */
1967 void
1969 {
1971 }
1973 /* TYPE is a class type. Returns true if TYPE is an explicitly
1974 specialized class. */
1976 bool
1978 {
1982 }
1984 /* Print the list of functions at FNS, going through all the overloads
1985 for each element of the list. Alternatively, FNS cannot be a
1986 TREE_LIST, in which case it will be printed together with all the
1987 overloads.
1989 MORE and *STR should respectively be FALSE and NULL when the function
1990 is called from the outside. They are used internally on recursive
1991 calls. print_candidates manages the two parameters and leaves NULL
1992 in *STR when it ends. */
1994 static void
1996 {
2000 else
2002 {
2008 {
2011 else
2014 }
2016 }
2017 }
2019 /* Print the list of candidate FNS in an error message. FNS can also
2020 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
2022 void
2024 {
2028 }
2030 /* Get a (possibly) constrained template declaration for the
2031 purpose of ordering candidates. */
2032 static tree
2034 {
2040 }
2042 /* Among candidates having the same signature, return the
2043 most constrained or NULL_TREE if there is no best candidate.
2044 If the signatures of candidates vary (e.g., template
2045 specialization vs. member function), then there can be no
2046 most constrained.
2048 Note that we don't compare constraints on the functions
2049 themselves, but rather those of their templates. */
2050 static tree
2052 {
2053 // Try to find the best candidate in a first pass.
2056 {
2063 }
2065 // Verify that the champ is better than previous candidates.
2070 }
2073 }
2076 /* Returns the template (one of the functions given by TEMPLATE_ID)
2077 which can be specialized to match the indicated DECL with the
2078 explicit template args given in TEMPLATE_ID. The DECL may be
2079 NULL_TREE if none is available. In that case, the functions in
2080 TEMPLATE_ID are non-members.
2082 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2083 specialization of a member template.
2085 The TEMPLATE_COUNT is the number of references to qualifying
2086 template classes that appeared in the name of the function. See
2087 check_explicit_specialization for a more accurate description.
2089 TSK indicates what kind of template declaration (if any) is being
2090 declared. TSK_TEMPLATE indicates that the declaration given by
2091 DECL, though a FUNCTION_DECL, has template parameters, and is
2092 therefore a template function.
2094 The template args (those explicitly specified and those deduced)
2095 are output in a newly created vector *TARGS_OUT.
2097 If it is impossible to determine the result, an error message is
2098 issued. The error_mark_node is returned to indicate failure. */
2100 static tree
2102 tree decl,
2106 tmpl_spec_kind tsk)
2107 {
2108 tree fns;
2109 tree targs;
2110 tree explicit_targs;
2113 /* A TREE_LIST of templates of which DECL may be a specialization.
2114 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2115 corresponding TREE_PURPOSE is the set of template arguments that,
2116 when used to instantiate the template, would produce a function
2117 with the signature of DECL. */
2127 /* We shouldn't be specializing a member template of an
2128 unspecialized class template; we already gave an error in
2129 check_specialization_scope, now avoid crashing. */
2133 {
2136 }
2144 /* Check for baselinks. */
2149 {
2153 }
2155 {
2158 }
2160 /* Count the number of template headers specified for this
2161 specialization. */
2172 {
2175 tf_warning_or_error);
2179 }
2181 {
2185 {
2186 tree decl_arg_types;
2187 tree fn_arg_types;
2189 /* In case of explicit specialization, we need to check if
2190 the number of template headers appearing in the specialization
2191 is correct. This is usually done in check_explicit_specialization,
2192 but the check done there cannot be exhaustive when specializing
2193 member functions. Consider the following code:
2195 template <> void A<int>::f(int);
2196 template <> template <> void A<int>::f(int);
2198 Assuming that A<int> is not itself an explicit specialization
2199 already, the first line specializes "f" which is a non-template
2200 member function, whilst the second line specializes "f" which
2201 is a template member function. So both lines are syntactically
2202 correct, and check_explicit_specialization does not reject
2203 them.
2205 Here, we can do better, as we are matching the specialization
2206 against the declarations. We count the number of template
2207 headers, and we check if they match TEMPLATE_COUNT + 1
2208 (TEMPLATE_COUNT is the number of qualifying template classes,
2209 plus there must be another header for the member template
2210 itself).
2212 Notice that if header_count is zero, this is not a
2213 specialization but rather a template instantiation, so there
2214 is no check we can perform here. */
2216 {
2219 }
2221 /* Check that the number of template arguments at the
2222 innermost level for DECL is the same as for FN. */
2230 /* DECL might be a specialization of FN. */
2234 /* For a non-static member function, we need to make sure
2235 that the const qualification is the same. Since
2236 get_bindings does not try to merge the "this" parameter,
2237 we must do the comparison explicitly. */
2239 {
2244 /* And the ref-qualification. */
2248 }
2250 /* Skip the "this" parameter and, for constructors of
2251 classes with virtual bases, the VTT parameter. A
2252 full specialization of a constructor will have a VTT
2253 parameter, but a template never will. */
2254 decl_arg_types
2256 fn_arg_types
2259 /* Function templates cannot be specializations; there are
2260 no partial specializations of functions. Therefore, if
2261 the type of DECL does not match FN, there is no
2262 match.
2264 Note that it should never be the case that we have both
2265 candidates added here, and for regular member functions
2266 below. */
2268 {
2270 current_template_parms))
2283 {
2284 /* C++20 CA104: Substitute directly into the
2285 constraint-expression. */
2291 }
2295 }
2297 /* See whether this function might be a specialization of this
2298 template. Suppress access control because we might be trying
2299 to make this specialization a friend, and we have already done
2300 access control for the declaration of the specialization. */
2306 /* We cannot deduce template arguments that when used to
2307 specialize TMPL will produce DECL. */
2311 /* We deduced something involving 'auto', which isn't a valid
2312 template argument. */
2315 /* Save this template, and the arguments deduced. */
2317 }
2319 /* FN is an ordinary member function, and we need a
2320 specialization of a member template. */
2321 ;
2323 /* We can get IDENTIFIER_NODEs here in certain erroneous
2324 cases. */
2325 ;
2327 /* This is just an ordinary non-member function. Nothing can
2328 be a specialization of that. */
2329 ;
2331 /* Cannot specialize functions that are created implicitly. */
2332 ;
2333 else
2334 {
2335 tree decl_arg_types;
2337 /* This is an ordinary member function. However, since
2338 we're here, we can assume its enclosing class is a
2339 template class. For example,
2341 template <typename T> struct S { void f(); };
2342 template <> void S<int>::f() {}
2344 Here, S<int>::f is a non-template, but S<int> is a
2345 template class. If FN has the same type as DECL, we
2346 might be in business. */
2349 /* Its enclosing class is an explicit specialization
2350 of a template class. This is not a candidate. */
2355 /* The return types differ. */
2358 /* Adjust the type of DECL in case FN is a static member. */
2365 decl_arg_types))
2373 // If the deduced arguments do not satisfy the constraints,
2374 // this is not a candidate.
2378 // Add the candidate.
2380 }
2381 }
2384 {
2385 /* We have:
2387 [temp.expl.spec]
2389 It is possible for a specialization with a given function
2390 signature to be instantiated from more than one function
2391 template. In such cases, explicit specification of the
2392 template arguments must be used to uniquely identify the
2393 function template specialization being specialized.
2395 Note that here, there's no suggestion that we're supposed to
2396 determine which of the candidate templates is most
2397 specialized. However, we, also have:
2399 [temp.func.order]
2401 Partial ordering of overloaded function template
2402 declarations is used in the following contexts to select
2403 the function template to which a function template
2404 specialization refers:
2406 -- when an explicit specialization refers to a function
2407 template.
2409 So, we do use the partial ordering rules, at least for now.
2410 This extension can only serve to make invalid programs valid,
2411 so it's safe. And, there is strong anecdotal evidence that
2412 the committee intended the partial ordering rules to apply;
2413 the EDG front end has that behavior, and John Spicer claims
2414 that the committee simply forgot to delete the wording in
2415 [temp.expl.spec]. */
2418 {
2421 }
2422 }
2424 // Concepts allows multiple declarations of member functions
2425 // with the same signature. Like above, we need to rely on
2426 // on the partial ordering of those candidates to determine which
2427 // is the best.
2429 {
2431 {
2434 }
2435 }
2438 {
2443 "saw %d %<template<>%>, need %d for "
2448 }
2452 {
2458 }
2460 /* We have one, and exactly one, match. */
2462 {
2466 /* Propagate the candidate's constraints to the declaration. */
2470 /* DECL is a re-declaration or partial instantiation of a template
2471 function. */
2474 /* It was a specialization of an ordinary member function in a
2475 template class. */
2477 }
2479 /* It was a specialization of a template. */
2483 /* Propagate the template's constraints to the declaration. */
2488 }
2490 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2491 but with the default argument values filled in from those in the
2492 TMPL_TYPES. */
2494 static tree
2496 tree tmpl_types)
2497 {
2498 tree new_spec_types;
2506 /* Substitute into the rest of the list. */
2507 new_spec_types =
2511 /* Add the default argument for this parameter. */
2514 new_spec_types);
2515 }
2517 /* DECL is an explicit specialization. Replicate default arguments
2518 from the template it specializes. (That way, code like:
2520 template <class T> void f(T = 3);
2521 template <> void f(double);
2522 void g () { f (); }
2524 works, as required.) An alternative approach would be to look up
2525 the correct default arguments at the call-site, but this approach
2526 is consistent with how implicit instantiations are handled. */
2528 static void
2530 {
2531 tree tmpl;
2532 tree spec_types;
2533 tree tmpl_types;
2534 tree new_spec_types;
2535 tree old_type;
2536 tree new_type;
2537 tree t;
2542 /* See if there's anything we need to do. */
2555 {
2556 /* Remove the this pointer, but remember the object's type for
2557 CV quals. */
2563 {
2564 /* DECL may contain more parameters than TMPL due to the extra
2565 in-charge parameter in constructors and destructors. */
2568 }
2570 {
2573 }
2574 }
2576 /* Compute the merged default arguments. */
2577 new_spec_types =
2580 /* Compute the new FUNCTION_TYPE. */
2582 {
2586 new_spec_types);
2589 /* Put the in-charge parameter back. */
2592 new_spec_types);
2596 new_spec_types);
2597 }
2598 else
2600 new_spec_types);
2606 }
2608 /* Return the number of template headers we expect to see for a definition
2609 or specialization of CTYPE or one of its non-template members. */
2611 int
2613 {
2617 {
2618 /* You're supposed to have one `template <...>' for every
2619 template class, but you don't need one for a full
2620 specialization. For example:
2622 template <class T> struct S{};
2623 template <> struct S<int> { void f(); };
2624 void S<int>::f () {}
2626 is correct; there shouldn't be a `template <>' for the
2627 definition of `S<int>::f'. */
2629 /* If CTYPE does not have template information of any
2630 kind, then it is not a template, nor is it nested
2631 within a template. */
2639 }
2642 }
2644 /* Do a simple sanity check on the template headers that precede the
2645 variable declaration DECL. */
2647 void
2649 {
2654 {
2657 "variable templates only available with "
2660 // Namespace-scope variable templates should have a template header.
2662 }
2664 {
2665 auto_diagnostic_group d;
2667 "too many template headers for %qD "
2673 "members of an explicitly specialized class are defined "
2675 }
2676 }
2678 /* An explicit specialization whose declarator-id or class-head-name is not
2679 qualified shall be declared in the nearest enclosing namespace of the
2680 template, or, if the namespace is inline (7.3.1), any namespace from its
2681 enclosing namespace set.
2683 If the name declared in the explicit instantiation is an unqualified name,
2684 the explicit instantiation shall appear in the namespace where its template
2685 is declared or, if that namespace is inline (7.3.1), any namespace from its
2686 enclosing namespace set. */
2688 void
2690 {
2695 {
2701 /* This was allowed in C++98, so only pedwarn. */
2703 "outside its namespace must use a nested-name-"
2705 }
2706 }
2708 /* Warn for a template specialization SPEC that is missing some of a set
2709 of function or type attributes that the template TEMPL is declared with.
2710 ATTRLIST is a list of additional attributes that SPEC should be taken
2711 to ultimately be declared with. */
2713 static void
2715 {
2719 /* Avoid warning if the difference between the primary and
2720 the specialization is not in one of the attributes below. */
2724 };
2726 /* Put together a list of the black listed attributes that the primary
2727 template is declared with that the specialization is not, in case
2728 it's not apparent from the most recent declaration of the primary. */
2729 pretty_printer str;
2736 auto_diagnostic_group d;
2739 spec))
2745 }
2747 /* Check to see if the function just declared, as indicated in
2748 DECLARATOR, and in DECL, is a specialization of a function
2749 template. We may also discover that the declaration is an explicit
2750 instantiation at this point.
2752 Returns DECL, or an equivalent declaration that should be used
2753 instead if all goes well. Issues an error message if something is
2754 amiss. Returns error_mark_node if the error is not easily
2755 recoverable.
2757 FLAGS is a bitmask consisting of the following flags:
2759 2: The function has a definition.
2760 4: The function is a friend.
2762 The TEMPLATE_COUNT is the number of references to qualifying
2763 template classes that appeared in the name of the function. For
2764 example, in
2766 template <class T> struct S { void f(); };
2767 void S<int>::f();
2769 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2770 classes are not counted in the TEMPLATE_COUNT, so that in
2772 template <class T> struct S {};
2773 template <> struct S<int> { void f(); }
2774 template <> void S<int>::f();
2776 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2777 invalid; there should be no template <>.)
2779 If the function is a specialization, it is marked as such via
2780 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2781 is set up correctly, and it is added to the list of specializations
2782 for that template. */
2784 tree
2786 tree decl,
2789 tree attrlist)
2790 {
2799 tmpl_spec_kind tsk;
2802 {
2805 else
2807 }
2808 else
2812 {
2815 {
2818 }
2822 {
2824 /* This could be something like:
2826 template <class T> void f(T);
2827 class S { friend void f<>(int); } */
2829 else
2830 {
2831 /* This case handles bogus declarations like template <>
2832 template <class T> void f<int>(); */
2836 declarator);
2838 }
2839 }
2843 /* The error has already been reported in
2844 check_specialization_scope. */
2850 /* Fall through. */
2863 decl);
2866 else
2870 /* Fall through. */
2876 /* In cases like template<> constexpr bool v = true;
2877 We'll give an error in check_template_variable. */
2883 else
2889 {
2890 /* This case handles bogus declarations like template <>
2891 template <class T> void f<int>(); */
2896 declarator);
2898 {
2899 /* Partial specialization of variable template. */
2903 }
2906 "non-type partial specialization %qE "
2908 else
2910 "non-class, non-variable partial specialization %qE "
2913 ok:;
2914 }
2917 /* This is a specialization of a member template, without
2918 specialization the containing class. Something like:
2920 template <class T> struct S {
2921 template <class U> void f (U);
2922 };
2923 template <> template <class U> void S<int>::f(U) {}
2925 That's a specialization -- but of the entire template. */
2931 }
2934 /* This doesn't apply to variable templates. */
2936 {
2940 {
2944 }
2945 }
2948 {
2954 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2956 {
2957 tree fns;
2962 else
2963 {
2964 /* If there is no class context, the explicit instantiation
2965 must be at namespace scope. */
2968 /* Find the namespace binding, using the declaration
2969 context. */
2973 {
2974 /* If lookup fails, look for a friend declaration so we can
2975 give a better diagnostic. */
2976 fns = (lookup_qualified_name
2981 }
2984 {
2987 }
2988 }
2991 }
2997 {
2999 /* A specialization in class scope. This is invalid,
3000 but the error will already have been flagged by
3001 check_specialization_scope. */
3003 else
3004 {
3005 /* It's not valid to write an explicit instantiation in
3006 class scope, e.g.:
3008 class C { template void f(); }
3010 This case is caught by the parser. However, on
3011 something like:
3013 template class C { void f(); };
3015 (which is invalid) we can get here. The error will be
3016 issued later. */
3017 ;
3018 }
3021 }
3024 {
3025 // We'll match variable templates in start_decl.
3029 /* Find the list of functions in ctype that have the same
3030 name as the declared function. */
3034 {
3038 {
3039 /* From [temp.expl.spec]:
3041 If such an explicit specialization for the member
3042 of a class template names an implicitly-declared
3043 special member function (clause _special_), the
3044 program is ill-formed.
3046 Similar language is found in [temp.explicit]. */
3049 }
3052 }
3054 /* For a type-conversion operator, We might be looking for
3055 `operator int' which will be a specialization of
3056 `operator T'. Grab all the conversion operators, and
3057 then select from them. */
3062 {
3065 }
3066 else
3068 }
3070 /* Figure out what exactly is being specialized at this point.
3071 Note that for an explicit instantiation, even one for a
3072 member function, we cannot tell a priori whether the
3073 instantiation is for a member template, or just a member
3074 function of a template class. Even if a member template is
3075 being instantiated, the member template arguments may be
3076 elided if they can be deduced from the rest of the
3077 declaration. */
3080 member_specialization,
3081 template_count,
3082 tsk);
3085 /* We couldn't figure out what this declaration was
3086 specializing. */
3088 else
3089 {
3091 {
3092 auto_diagnostic_group d;
3094 "friend declaration %qD is not visible to "
3098 }
3107 {
3108 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3109 is done by do_decl_instantiation later. */
3115 {
3116 /* If TMPL is not the most general template (for
3117 example, if TMPL is a friend template that is
3118 injected into namespace scope), then there will
3119 be too many levels of TARGS. Remove some of them
3120 here. */
3122 tree new_targs;
3129 }
3132 }
3134 /* If we thought that the DECL was a member function, but it
3135 turns out to be specializing a static member function,
3136 make DECL a static member function as well. */
3142 /* If this is a specialization of a member template of a
3143 template class, we want to return the TEMPLATE_DECL, not
3144 the specialization of it. */
3146 {
3151 {
3152 tree parm;
3156 /* We want to use the argument list specified in the
3157 definition, not in the original declaration. */
3162 }
3167 }
3169 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3175 /* Inherit default function arguments from the template
3176 DECL is specializing. */
3180 /* This specialization has the same protection as the
3181 template it specializes. */
3185 /* 7.1.1-1 [dcl.stc]
3187 A storage-class-specifier shall not be specified in an
3188 explicit specialization...
3190 The parser rejects these, so unless action is taken here,
3191 explicit function specializations will always appear with
3192 global linkage.
3194 The action recommended by the C++ CWG in response to C++
3195 defect report 605 is to make the storage class and linkage
3196 of the explicit specialization match the templated function:
3198 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3199 */
3201 {
3205 /* A concept cannot be specialized. */
3207 {
3209 gen_tmpl);
3211 }
3213 /* This specialization has the same linkage and visibility as
3214 the function template it specializes. */
3217 {
3220 }
3223 {
3226 }
3227 }
3229 /* If DECL is a friend declaration, declared using an
3230 unqualified name, the namespace associated with DECL may
3231 have been set incorrectly. For example, in:
3233 template <typename T> void f(T);
3234 namespace N {
3235 struct S { friend void f<int>(int); }
3236 }
3238 we will have set the DECL_CONTEXT for the friend
3239 declaration to N, rather than to the global namespace. */
3244 /* This is not really a declaration of a specialization.
3245 It's just the name of an instantiation. But, it's not
3246 a request for an instantiation, either. */
3249 /* A specialization is not necessarily COMDAT. */
3255 /* If this is a full specialization, register it so that we can find
3256 it again. Partial specializations will be registered in
3257 process_partial_specialization. */
3259 {
3264 }
3266 /* If this is a specialization, splice any contracts that may have
3267 been inherited from the template, removing them. */
3271 /* A 'structor should already have clones. */
3277 }
3278 }
3281 }
3283 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3284 parameters. These are represented in the same format used for
3285 DECL_TEMPLATE_PARMS. */
3287 int
3289 {
3290 const_tree p1;
3291 const_tree p2;
3299 {
3311 {
3315 /* If either of the template parameters are invalid, assume
3316 they match for the sake of error recovery. */
3329 }
3330 }
3333 /* One set of parameters has more parameters lists than the
3334 other. */
3338 }
3340 /* Returns true if two template parameters are declared with
3341 equivalent constraints. */
3343 static bool
3345 {
3353 }
3355 /* Returns true when two template parameters are equivalent. */
3357 static bool
3359 {
3363 /* If either of the template parameters are invalid, assume
3364 they match for the sake of error recovery. */
3368 /* ... they declare parameters of the same kind. */
3372 /* ... one parameter was introduced by a parameter declaration, then
3373 both are. This case arises as a result of eagerly rewriting declarations
3374 during parsing. */
3378 /* ... if either declares a pack, they both do. */
3383 {
3384 /* ... if they declare non-type parameters, the types are equivalent. */
3387 }
3389 {
3390 /* ... if they declare template template parameters, their template
3391 parameter lists are equivalent. */
3394 }
3396 /* ... if they are declared with a qualified-concept name, they both
3397 are, and those names are equivalent. */
3399 }
3401 /* Returns true if two template parameters lists are equivalent.
3402 Two template parameter lists are equivalent if they have the
3403 same length and their corresponding parameters are equivalent.
3405 PARMS1 and PARMS2 are TREE_LISTs containing TREE_VECs: the
3406 data structure returned by DECL_TEMPLATE_PARMS.
3408 This is generally the same implementation as comp_template_parms
3409 except that it also the concept names and arguments used to
3410 introduce parameters. */
3412 static bool
3414 {
3421 {
3429 {
3434 }
3438 }
3444 }
3446 /* Return true if the requires-clause of the template parameter lists are
3447 equivalent and false otherwise. */
3448 static bool
3450 {
3458 }
3460 /* Returns true if two template heads are equivalent. 17.6.6.1p6:
3461 Two template heads are equivalent if their template parameter
3462 lists are equivalent and their requires clauses are equivalent.
3464 In pre-C++20, this is equivalent to calling comp_template_parms
3465 for the template parameters of TMPL1 and TMPL2. */
3467 bool
3469 {
3473 /* Don't change the matching rules for pre-C++20. */
3477 /* ... have the same number of template parameters, and their
3478 corresponding parameters are equivalent. */
3482 /* ... if either has a requires-clause, they both do and their
3483 corresponding constraint-expressions are equivalent. */
3485 }
3487 /* Determine whether PARM is a parameter pack. */
3489 bool
3491 {
3492 /* Determine if we have a non-type template parameter pack. */
3499 /* If this is a list of template parameters, we could get a
3500 TYPE_DECL or a TEMPLATE_DECL. */
3504 /* Otherwise it must be a type template parameter. */
3508 }
3510 /* Determine if T is a function parameter pack. */
3512 bool
3514 {
3518 }
3520 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3521 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3523 tree
3525 {
3532 }
3534 /* Return true iff the function parameter PARAM_DECL was expanded
3535 from the function parameter pack PACK. */
3537 bool
3539 {
3544 /* The parameter pack and its pack arguments have the same
3545 DECL_PARM_INDEX. */
3547 }
3549 /* Determine whether ARGS describes a variadic template args list,
3550 i.e., one that is terminated by a template argument pack. */
3552 static bool
3554 {
3556 tree last_parm;
3570 }
3572 /* Generate a new name for the parameter pack name NAME (an
3573 IDENTIFIER_NODE) that incorporates its */
3575 static tree
3577 {
3578 /* Munge the name to include the parameter index. */
3579 #define NUMBUF_LEN 128
3593 }
3595 /* Return true if T is a primary function, class or alias template
3596 specialization, not including the template pattern. */
3598 bool
3600 {
3616 }
3618 /* Return true if PARM is a template template parameter. */
3620 bool
3622 {
3624 }
3626 /* Return true iff PARM is a DECL representing a type template
3627 parameter. */
3629 bool
3631 {
3636 }
3638 /* Return the template parameters of T if T is a
3639 primary template instantiation, NULL otherwise. */
3641 tree
3643 {
3648 parms = INNERMOST_TEMPLATE_PARMS
3652 }
3654 /* Returns the template arguments of T if T is a template instantiation,
3655 NULL otherwise. */
3657 tree
3659 {
3667 }
3669 /* Return the argument pack elements of T if T is a template argument pack,
3670 NULL otherwise. */
3672 tree
3674 {
3680 }
3682 /* In an ARGUMENT_PACK_SELECT, the actual underlying argument that the
3683 ARGUMENT_PACK_SELECT represents. */
3685 static tree
3687 {
3691 /* If the selected argument is an expansion E, that most likely means we were
3692 called from gen_elem_of_pack_expansion_instantiation during the
3693 substituting of an argument pack (of which the Ith element is a pack
3694 expansion, where I is ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
3695 In this case, the Ith element resulting from this substituting is going to
3696 be a pack expansion, which pattern is the pattern of E. Let's return the
3697 pattern of E, and gen_elem_of_pack_expansion_instantiation will build the
3698 resulting pack expansion from it. */
3700 {
3701 /* Make sure we aren't throwing away arg info. */
3704 }
3707 }
3709 /* Return a modification of ARGS that's suitable for preserving inside a hash
3710 table. In particular, this replaces each ARGUMENT_PACK_SELECT with its
3711 underlying argument. ARGS is copied (upon modification) iff COW_P. */
3713 static tree
3715 {
3720 {
3722 tree r;
3729 else
3732 {
3734 {
3737 }
3739 }
3740 }
3743 }
3745 /* True iff FN is a function representing a built-in variadic parameter
3746 pack. */
3748 bool
3750 {
3760 }
3762 /* True iff CALL is a call to a function representing a built-in variadic
3763 parameter pack. */
3765 static bool
3767 {
3771 }
3773 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3775 static tree
3777 tree in_decl)
3778 {
3783 {
3785 {
3788 }
3793 }
3794 else
3795 {
3800 /* Calculate the largest value of len that won't make the size of the vec
3801 overflow an int. The compiler will exceed resource limits long before
3802 this, but it seems a decent place to diagnose. */
3806 {
3810 max);
3812 }
3820 }
3821 }
3823 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3824 CALL. */
3826 static tree
3828 tree in_decl)
3829 {
3839 }
3841 /* Return true if the tree T has the extra args mechanism for
3842 avoiding partial instantiation. */
3844 static bool
3846 {
3851 }
3853 /* Structure used to track the progress of find_parameter_packs_r. */
3854 struct find_parameter_pack_data
3855 {
3856 /* TREE_LIST that will contain all of the parameter packs found by
3857 the traversal. */
3860 /* Set of AST nodes that have been visited by the traversal. */
3863 /* True iff we're making a type pack expansion. */
3866 /* True iff we found a subtree that has the extra args mechanism. */
3868 };
3870 /* Identifies all of the argument packs that occur in a template
3871 argument and appends them to the TREE_LIST inside DATA, which is a
3872 find_parameter_pack_data structure. This is a subroutine of
3873 make_pack_expansion and uses_parameter_packs. */
3874 static tree
3876 {
3882 #define WALK_SUBTREE(NODE) \
3883 cp_walk_tree (&(NODE), &find_parameter_packs_r, \
3884 ppd, ppd->visited) \
3886 /* Don't look through typedefs; we are interested in whether a
3887 parameter pack is actually written in the expression/type we're
3888 looking at, not the target type. */
3890 {
3891 /* But do look at arguments for an alias template. */
3898 }
3900 /* Identify whether this is a parameter pack or not. */
3902 {
3910 /* FALLTHRU */
3912 /* If the placeholder appears in the decl-specifier-seq of a function
3913 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3914 is a pack expansion, the invented template parameter is a template
3915 parameter pack. */
3925 {
3926 /* We don't want to walk into the type of a PARM_DECL,
3927 because we don't want to see the type parameter pack. */
3930 }
3935 {
3936 /* We don't want to walk into the type of a variadic capture proxy,
3937 because we don't want to see the type parameter pack. */
3940 }
3942 {
3944 find_parameter_packs_r,
3947 }
3959 /* Not a parameter pack. */
3961 }
3964 {
3965 /* Add this parameter pack to the list. */
3967 }
3976 /* This switch statement will return immediately if we don't find a
3977 parameter pack. ??? Should some of these be in cp_walk_subtrees? */
3979 {
3981 /* Check the template itself. */
3987 {
3989 /* Ignore the declaration of a capture proxy for a parameter pack. */
3993 /* Since we stop at typedefs above, we need to look through them at
3994 the point of the DECL_EXPR. */
3998 }
4025 {
4026 /* Since we defer implicit capture, look in the parms and body. */
4033 }
4036 {
4037 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
4038 type_pack_expansion_p to false so that any placeholders
4039 within the expression don't get marked as parameter packs. */
4047 }
4056 /* Don't walk into IF_STMT_EXTRA_ARGS. */
4063 {
4064 /* Local class, need to look through the whole definition.
4065 TYPE_BINFO might be unset for a partial instantiation. */
4070 }
4071 else
4072 /* Enum, look at the values. */
4086 }
4088 #undef WALK_SUBTREE
4091 }
4093 /* Determines if the expression or type T uses any parameter packs. */
4094 tree
4096 {
4105 }
4107 /* Turn ARG, which may be an expression, type, or a TREE_LIST
4108 representation a base-class initializer into a parameter pack
4109 expansion. If all goes well, the resulting node will be an
4110 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
4111 respectively. */
4112 tree
4114 {
4115 tree result;
4124 {
4125 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
4126 class initializer. In this case, the TREE_PURPOSE will be a
4127 _TYPE node (representing the base class expansion we're
4128 initializing) and the TREE_VALUE will be a TREE_LIST
4129 containing the initialization arguments.
4131 The resulting expansion looks somewhat different from most
4132 expansions. Rather than returning just one _EXPANSION, we
4133 return a TREE_LIST whose TREE_PURPOSE is a
4134 TYPE_PACK_EXPANSION containing the bases that will be
4135 initialized. The TREE_VALUE will be identical to the
4136 original TREE_VALUE, which is a list of arguments that will
4137 be passed to each base. We do not introduce any new pack
4138 expansion nodes into the TREE_VALUE (although it is possible
4139 that some already exist), because the TREE_PURPOSE and
4140 TREE_VALUE all need to be expanded together with the same
4141 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
4142 resulting TREE_PURPOSE will mention the parameter packs in
4143 both the bases and the arguments to the bases. */
4144 tree purpose;
4145 tree value;
4148 /* Determine which parameter packs will be used by the base
4149 class expansion. */
4158 {
4161 arg);
4164 }
4167 {
4168 /* Collect the sets of parameter packs used in each of the
4169 initialization arguments. */
4171 {
4172 /* Determine which parameter packs will be expanded in this
4173 argument. */
4176 }
4177 }
4181 /* Create the pack expansion type for the base type. */
4187 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4188 they will rarely be compared to anything. */
4192 }
4197 /* Build the PACK_EXPANSION_* node. */
4198 result = for_types
4203 {
4204 /* Propagate type and const-expression information. */
4207 /* Mark this read now, since the expansion might be length 0. */
4209 }
4210 else
4211 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4212 they will rarely be compared to anything. */
4215 /* Determine which parameter packs will be expanded. */
4222 /* Make sure we found some parameter packs. */
4224 {
4226 {
4229 else
4231 }
4233 }
4238 /* If the pattern of this pack expansion contains a subtree that has
4239 the extra args mechanism for avoiding partial instantiation, then
4240 force this pack expansion to also use extra args. Otherwise
4241 partial instantiation of this pack expansion may not lower the
4242 level of some parameter packs within the pattern, which would
4243 confuse tsubst_pack_expansion later (PR101764). */
4247 }
4249 /* Checks T for any "bare" parameter packs, which have not yet been
4250 expanded, and issues an error if any are found. This operation can
4251 only be done on full expressions or types (e.g., an expression
4252 statement, "if" condition, etc.), because we could have expressions like:
4254 foo(f(g(h(args)))...)
4256 where "args" is a parameter pack. check_for_bare_parameter_packs
4257 should not be called for the subexpressions args, h(args),
4258 g(h(args)), or f(g(h(args))), because we would produce erroneous
4259 error messages.
4261 Returns TRUE and emits an error if there were bare parameter packs,
4262 returns FALSE otherwise. */
4263 bool
4265 {
4287 /* It's OK for a lambda to have an unexpanded parameter pack from the
4288 containing context, but do complain about unexpanded capture packs. */
4294 {
4295 /* We're in a lambda, but it isn't the innermost class.
4296 This should work, but currently doesn't. */
4299 }
4304 {
4310 }
4313 {
4316 {
4327 else
4332 else
4336 }
4339 }
4342 }
4344 /* Expand any parameter packs that occur in the template arguments in
4345 ARGS. */
4346 tree
4348 {
4357 /* First, determine if we need to expand anything, and the number of
4358 slots we'll need. */
4360 {
4365 {
4369 else
4371 }
4372 else
4373 {
4375 num_result_args++;
4376 }
4377 }
4379 /* If no expansion is necessary, we're done. */
4383 /* Expand arguments. */
4386 non_default_args_count =
4389 {
4392 {
4399 }
4400 else
4401 {
4404 }
4405 }
4409 }
4411 /* Checks if DECL shadows a template parameter.
4413 [temp.local]: A template-parameter shall not be redeclared within its
4414 scope (including nested scopes).
4416 Emits an error and returns TRUE if the DECL shadows a parameter,
4417 returns FALSE otherwise. */
4419 bool
4421 {
4422 tree olddecl;
4424 /* If we're not in a template, we can't possibly shadow a template
4425 parameter. */
4429 /* Figure out what we're shadowing. */
4433 /* If there's no previous binding for this name, we're not shadowing
4434 anything, let alone a template parameter. */
4438 /* If we're not shadowing a template parameter, we're done. Note
4439 that OLDDECL might be an OVERLOAD (or perhaps even an
4440 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4441 node. */
4445 /* We check for decl != olddecl to avoid bogus errors for using a
4446 name inside a class. We check TPFI to avoid duplicate errors for
4447 inline member templates. */
4453 /* Don't complain about the injected class name, as we've already
4454 complained about the class itself. */
4461 else
4466 }
4468 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4469 ORIG_LEVEL, DECL, and TYPE. */
4471 static tree
4475 tree decl,
4476 tree type)
4477 {
4488 }
4491 {
4493 {
4503 }
4506 {
4511 }
4512 };
4516 /* Find the canonical type parameter for the given template type
4517 parameter. Returns the canonical type parameter, which may be TYPE
4518 if no such parameter existed. */
4520 tree
4522 {
4530 }
4532 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4533 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4534 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4535 new one is created. */
4537 static tree
4539 tsubst_flags_t complain)
4540 {
4545 {
4550 type);
4565 /* Template template parameters need this. */
4568 {
4575 }
4577 /* Attach the TPI to the decl. */
4580 else
4582 }
4585 }
4587 /* Process information from new template parameter PARM and append it
4588 to the LIST being built. This new parameter is a non-type
4589 parameter iff IS_NON_TYPE is true. This new parameter is a
4590 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4591 is in PARM_LOC. */
4593 tree
4596 {
4602 {
4612 }
4619 {
4625 {
4626 /* [temp.param]
4628 The top-level cv-qualifiers on the template-parameter are
4629 ignored when determining its type. */
4634 && !is_parameter_pack
4635 /* If we're in a nested template parameter list, the template
4636 template parameter could be a parameter pack. */
4638 {
4639 /* This template parameter is not a parameter pack, but it
4640 should be. Complain about "bare" parameter packs. */
4643 /* Recover by calling this a parameter pack. */
4645 }
4646 }
4648 /* A template parameter is not modifiable. */
4657 current_template_depth,
4662 }
4663 else
4664 {
4665 tree t;
4669 {
4671 /* This is for distinguishing between real templates and template
4672 template parameters */
4675 /* any_template_parm_r expects to be able to get the targs of a
4676 DECL_TEMPLATE_RESULT. */
4685 }
4686 else
4687 {
4689 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4692 }
4699 current_template_depth,
4703 }
4711 /* Build requirements for the type/template parameter.
4712 This must be done after SET_DECL_TEMPLATE_PARM_P or
4713 process_template_parm could fail. */
4720 /* Build the parameter node linking the parameter declaration,
4721 its default argument (if any), and its constraints (if any). */
4727 else
4731 }
4733 /* The end of a template parameter list has been reached. Process the
4734 tree list into a parameter vector, converting each parameter into a more
4735 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4736 as PARM_DECLs. */
4738 tree
4740 {
4743 /* Pop the dummy parameter level and add the real one. We do not
4744 morph the dummy parameter in place, as it might have been
4745 captured by a (nested) template-template-parm. */
4748 current_template_parms
4753 {
4759 }
4764 }
4766 // Explicitly indicate the end of the template parameter list. We assume
4767 // that the current template parameters have been constructed and/or
4768 // managed explicitly, as when creating new template template parameters
4769 // from a shorthand constraint.
4770 void
4772 {
4774 }
4776 /* end_template_decl is called after a template declaration is seen. */
4778 void
4780 {
4786 /* This matches the pushlevel in begin_template_parm_list. */
4791 }
4793 /* Takes a TEMPLATE_PARM_P or DECL_TEMPLATE_PARM_P node or a TREE_LIST
4794 thereof, and converts it into an argument suitable to be passed to
4795 the type substitution functions. Note that if the TREE_LIST contains
4796 an error_mark node, the returned argument is error_mark_node. */
4798 tree
4800 {
4811 {
4815 else
4817 }
4823 {
4825 {
4826 /* Turn this argument into a TYPE_ARGUMENT_PACK
4827 with a single element, which expands T. */
4836 }
4837 }
4838 else
4839 {
4841 {
4842 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4843 with a single element, which expands T. */
4853 }
4854 else
4856 }
4858 }
4860 /* If T looks like a generic template argument produced by template_parm_to_arg,
4861 return the corresponding template parameter, otherwise return NULL_TREE. */
4863 static tree
4865 {
4870 {
4875 }
4882 else
4884 }
4886 /* Given a single level of template parameters (a TREE_VEC), return it
4887 as a set of template arguments. */
4889 tree
4891 {
4901 }
4903 /* Given a set of template parameters, return them as a set of template
4904 arguments. The template parameters are represented as a TREE_VEC, in
4905 the form documented in cp-tree.h for template arguments. */
4907 tree
4909 {
4910 tree header;
4915 /* If there is only one level of template parameters, we do not
4916 create a TREE_VEC of TREE_VECs. Instead, we return a single
4917 TREE_VEC containing the arguments. */
4922 {
4927 else
4929 }
4932 }
4934 /* Within the declaration of a template, return the currently active
4935 template parameters as an argument TREE_VEC. */
4937 static tree
4939 {
4941 }
4943 /* Return the fully generic arguments for of TMPL, i.e. what
4944 current_template_args would be while parsing it. */
4946 tree
4948 {
4953 /* DECL_TEMPLATE_RESULT doesn't have the arguments we want. For a template
4954 template parameter, it has no TEMPLATE_INFO; for a partial
4955 specialization, it has the arguments for the primary template, and we
4961 }
4963 /* Return the template arguments corresponding to the template parameters of
4964 TMPL's enclosing scope. When TMPL is a member of a partial specialization,
4965 this returns the arguments for the partial specialization as opposed to those
4966 for the primary template, which is the main difference between this function
4967 and simply using e.g. the TYPE_TI_ARGS of TMPL's DECL_CONTEXT. */
4969 tree
4971 {
4981 }
4983 /* Update the declared TYPE by doing any lookups which were thought to be
4984 dependent, but are not now that we know the SCOPE of the declarator. */
4986 tree
4988 {
4999 /* Don't bother building up the args in this case. */
5001 {
5002 /* tsubst in the args corresponding to the template parameters,
5003 including auto if present. Most things will be unchanged, but
5004 make_typename_type and tsubst_qualified_id will resolve
5005 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
5008 tree pushed;
5010 {
5014 }
5019 }
5025 {
5028 else
5030 }
5032 }
5034 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
5035 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
5036 the new template is a member template. */
5038 static tree
5040 {
5052 /* Propagate module information from the decl. */
5056 }
5058 struct template_parm_data
5059 {
5060 /* The level of the template parameters we are currently
5061 processing. */
5064 /* The index of the specialization argument we are currently
5065 processing. */
5068 /* An array whose size is the number of template parameters. The
5069 elements are nonzero if the parameter has been used in any one
5070 of the arguments processed so far. */
5073 /* An array whose size is the number of template arguments. The
5074 elements are nonzero if the argument makes use of template
5075 parameters of this level. */
5077 };
5079 /* Subroutine of push_template_decl used to see if each template
5080 parameter in a partial specialization is used in the explicit
5081 argument list. If T is of the LEVEL given in DATA (which is
5082 treated as a template_parm_data*), then DATA->PARMS is marked
5083 appropriately. */
5085 static int
5087 {
5095 {
5098 }
5100 /* In C++17 the type of a non-type argument is a deduced context. */
5105 data,
5106 NULL,
5109 /* Return zero so that for_each_template_parm will continue the
5110 traversal of the tree; we want to mark *every* template parm. */
5112 }
5114 /* Process the partial specialization DECL. */
5116 static tree
5118 {
5125 tree inner_parms;
5126 tree inst;
5136 /* A concept cannot be specialized. */
5138 {
5141 }
5146 /* We check that each of the template parameters given in the
5147 partial specialization is used in the argument list to the
5148 specialization. For example:
5150 template <class T> struct S;
5151 template <class T> struct S<T*>;
5153 The second declaration is OK because `T*' uses the template
5154 parameter T, whereas
5156 template <class T> struct S<int>;
5158 is no good. Even trickier is:
5160 template <class T>
5161 struct S1
5162 {
5163 template <class U>
5164 struct S2;
5165 template <class U>
5166 struct S2<T>;
5167 };
5169 The S2<T> declaration is actually invalid; it is a
5170 full-specialization. Of course,
5172 template <class U>
5173 struct S2<T (*)(U)>;
5175 or some such would have been OK. */
5183 {
5188 NULL,
5190 }
5193 {
5194 /* One of the template parms was not used in a deduced context in the
5195 specialization. */
5197 {
5201 }
5205 }
5210 /* [temp.class.spec]
5212 The argument list of the specialization shall not be identical to
5213 the implicit argument list of the primary template. */
5214 tree main_args
5217 && (!flag_concepts
5219 {
5222 "any template arguments; to define the primary template, "
5224 else
5226 "template arguments and is not more constrained than "
5227 "the primary template; to define the primary template, "
5230 }
5232 /* A partial specialization that replaces multiple parameters of the
5233 primary template with a pack expansion is less specialized for those
5234 parameters. */
5236 {
5238 "primary template because it replaces multiple parameters "
5241 /* Avoid crash in process_partial_specialization. */
5243 }
5246 {
5249 /* Avoid crash below. */
5251 }
5253 /* If we aren't in a dependent class, we can actually try deduction. */
5255 /* FIXME we should be able to handle a partial specialization of a
5256 partial instantiation, but currently we can't (c++/41727). */
5259 {
5260 auto_diagnostic_group d;
5263 decl))
5265 maintmpl);
5266 }
5268 /* [temp.spec.partial]
5270 The type of a template parameter corresponding to a specialized
5271 non-type argument shall not be dependent on a parameter of the
5272 specialization.
5274 Also, we verify that pack expansions only occur at the
5275 end of the argument list. */
5278 {
5285 {
5286 /* Extract the arguments from the argument pack. We'll be
5287 iterating over these in the following loop. */
5290 }
5293 {
5295 /* Get the Jth argument in the parameter pack. */
5299 {
5300 /* Pack expansions must come at the end of the
5301 argument list. */
5304 {
5308 else
5311 }
5312 }
5315 /* We only care about the pattern. */
5321 /* This next two lines are the `argument expression is not just a
5322 simple identifier' condition and also the `specialized
5323 non-type argument' bit. */
5328 {
5329 /* Look at the corresponding template parameter,
5330 marking which template parameters its type depends
5331 upon. */
5335 {
5336 /* We haven't yet initialized TPD2. Do so now. */
5338 /* The number of parameters here is the number in the
5339 main template, which, as checked in the assertion
5340 above, is NARGS. */
5344 }
5346 /* Mark the template parameters. But this time, we're
5347 looking for the template parameters of the main
5348 template, not in the specialization. */
5355 NULL,
5359 {
5360 /* The type depended on some template parameters.
5361 If they are fully specialized in the
5362 specialization, that's OK. */
5371 "type %qT of template argument %qE depends "
5373 "type %qT of template argument %qE depends "
5375 type,
5376 arg);
5377 }
5378 }
5379 }
5380 }
5382 /* We should only get here once. */
5386 // Build the template decl.
5393 /* Give template template parms a DECL_CONTEXT of the template
5394 for which they are a parameter. */
5396 {
5400 }
5403 /* We didn't register this in check_explicit_specialization so we could
5404 wait until the constraints were set. */
5406 else
5413 /* Link the DECL_TEMPLATE_RESULT back to the partial TEMPLATE_DECL. */
5419 {
5425 {
5434 "declaration of %qD ambiguates earlier template "
5438 "partial specialization of %qD after instantiation "
5440 }
5441 }
5444 }
5446 /* PARM is a template parameter of some form; return the corresponding
5447 TEMPLATE_PARM_INDEX. */
5449 static tree
5451 {
5464 }
5466 /* Subroutine of fixed_parameter_pack_p below. Look for any template
5467 parameter packs used by the template parameter PARM. */
5469 static void
5471 {
5472 /* A type parm can't refer to another parm. */
5476 {
5480 }
5486 {
5490 else
5492 }
5493 }
5495 /* PARM is a template parameter pack. Return any parameter packs used in
5496 its type or the type of any of its template parameters. If there are
5497 any such packs, it will be instantiated into a fixed template parameter
5498 list by partial instantiation rather than be fully deduced. */
5500 tree
5502 {
5503 /* This can only be true in a member template. */
5506 /* This can only be true for a parameter pack. */
5509 /* A type parm can't refer to another parm. */
5523 }
5525 /* Check that a template declaration's use of default arguments and
5526 parameter packs is not invalid. Here, PARMS are the template
5527 parameters. IS_PRIMARY is true if DECL is the thing declared by
5528 a primary template. IS_PARTIAL is true if DECL is a partial
5529 specialization.
5531 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
5532 function template declaration or a friend class template
5533 declaration. In the function case, 1 indicates a declaration, 2
5534 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
5535 emitted for extraneous default arguments.
5537 Returns TRUE if there were no errors found, FALSE otherwise. */
5539 bool
5542 {
5545 tree parm_level;
5548 /* [temp.param]
5550 A default template-argument shall not be specified in a
5551 function template declaration or a function template definition, nor
5552 in the template-parameter-list of the definition of a member of a
5553 class template. */
5557 /* You can't have a function template declaration in a local
5558 scope, nor you can you define a member of a class template in a
5559 local scope. */
5567 /* A lambda doesn't have an explicit declaration; don't complain
5568 about the parms of the enclosing class. */
5575 /* If this is either a friend defined in the scope of the class
5576 or a member function. */
5582 /* And, if it was a member function, it really was defined in
5583 the scope of the class. */
5586 /* We already checked these parameters when the template was
5587 declared, so there's no need to do it again now. This function
5588 was defined in class scope, but we're processing its body now
5589 that the class is complete. */
5592 /* Core issue 226 (C++0x only): the following only applies to class
5593 templates. */
5596 {
5597 /* [temp.param]
5599 If a template-parameter has a default template-argument, all
5600 subsequent template-parameters shall have a default
5601 template-argument supplied. */
5603 {
5610 {
5620 {
5622 /* For better subsequent error-recovery, we indicate that
5623 there should have been a default argument. */
5626 }
5628 && !is_friend_decl
5629 /* Don't complain about an enclosing partial
5630 specialization. */
5635 /* A fixed parameter pack will be partially
5636 instantiated into a fixed length list. */
5638 {
5639 /* A primary class template, primary variable template
5640 (DR 2032), or alias template can only have one
5641 parameter pack, at the end of the template
5642 parameter list. */
5650 }
5651 }
5652 }
5653 }
5656 || is_partial
5657 || !is_primary
5659 /* For an ordinary class template, default template arguments are
5660 allowed at the innermost level, e.g.:
5661 template <class T = int>
5662 struct S {};
5663 but, in a partial specialization, they're not allowed even
5664 there, as we have in [temp.class.spec]:
5666 The template parameter list of a specialization shall not
5667 contain default template argument values.
5669 So, for a partial specialization, or for a function template
5670 (in C++98/C++03), we look at all of them. */
5671 ;
5672 else
5673 /* But, for a primary class template that is not a partial
5674 specialization we look at all template parameters except the
5675 innermost ones. */
5678 /* Figure out what error message to issue. */
5693 else
5694 /* Per [temp.param]/9, "A default template-argument shall not be
5695 specified in the template-parameter-lists of the definition of
5696 a member of a class template that appears outside of the member's
5697 class.", thus if we aren't handling a member of a class template
5698 there is no need to examine the parameters. */
5702 /* If we're inside a class definition, there's no need to
5703 examine the parameters to the class itself. On the one
5704 hand, they will be checked when the class is defined, and,
5705 on the other, default arguments are valid in things like:
5706 template <class T = double>
5707 struct S { template <class U> void f(U); };
5708 Here the default argument for `S' has no bearing on the
5709 declaration of `f'. */
5711 else
5712 /* Check everything. */
5718 {
5725 {
5730 {
5732 {
5739 }
5741 /* Clear out the default argument so that we are not
5742 confused later. */
5744 }
5745 }
5747 /* At this point, if we're still interested in issuing messages,
5748 they must apply to classes surrounding the object declared. */
5752 }
5755 }
5757 /* Worker for push_template_decl_real, called via
5758 for_each_template_parm. DATA is really an int, indicating the
5759 level of the parameters we are interested in. If T is a template
5760 parameter of that level, return nonzero. */
5762 static int
5764 {
5770 else
5773 }
5775 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5776 DATA is really an int, indicating the innermost outer level of parameters.
5777 If T is a template parameter of that level or further out, return
5778 nonzero. */
5780 static int
5782 {
5788 else
5791 }
5793 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5794 parameters given by current_template_args, or reuses a
5795 previously existing one, if appropriate. Returns the DECL, or an
5796 equivalent one, if it is replaced via a call to duplicate_decls.
5798 If IS_FRIEND is true, DECL is a friend declaration. */
5800 tree
5802 {
5806 /* See if this is a partial specialization. */
5815 /* No surprising friend functions. */
5820 tree ctx;
5822 /* For a friend, we want the context of the friend, not
5823 the type of which it is a friend. */
5827 /* In the case of a virtual function, we want the class in which
5828 it is defined. */
5830 else
5831 /* Otherwise, if we're currently defining some class, the DECL
5832 is assumed to be a member of the class. */
5841 /* See if this is a primary template. */
5845 /* A friend template that specifies a class context, i.e.
5846 template <typename T> friend void A<T>::f();
5847 is not primary. */
5848 ;
5850 /* Lambdas are not primary. */
5851 ;
5852 else
5855 /* True if the template is a member template, in the sense of
5856 [temp.mem]. */
5860 {
5868 {
5871 }
5873 {
5875 {
5878 }
5880 {
5881 /* [temp.mem]
5883 A destructor shall not be a member template. */
5887 }
5894 {
5895 /* [basic.stc.dynamic.allocation]
5897 An allocation function can be a function
5898 template. ... Template allocation functions shall
5899 have two or more parameters. */
5902 }
5903 }
5909 /* alias-declaration */
5915 else
5916 {
5919 }
5920 }
5927 /* Check to see that the rules regarding the use of default
5928 arguments are not being violated. We check args for a friend
5929 functions when we know whether it's a definition, introducing
5930 declaration or re-declaration. */
5935 /* Ensure that there are no parameter packs in the type of this
5936 declaration that have not been expanded. */
5938 {
5939 /* Check each of the arguments individually to see if there are
5940 any bare parameter packs. */
5946 {
5949 {
5950 /* This is a PARM_DECL that contains unexpanded parameter
5951 packs. We have already complained about this in the
5952 check_for_bare_parameter_packs call, so just replace
5953 these types with ERROR_MARK_NODE. */
5956 }
5960 }
5962 /* Check for bare parameter packs in the return type and the
5963 exception specifiers. */
5965 /* Errors were already issued, set return type to int
5966 as the frontend doesn't expect error_mark_node as
5967 the return type. */
5971 }
5972 else
5973 {
5977 {
5980 }
5985 }
5994 {
5995 /* Does not get a template head. */
5998 }
6005 {
6010 /* If DECL is a TYPE_DECL for a class-template, then there won't
6011 be DECL_LANG_SPECIFIC. The information equivalent to
6012 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
6016 {
6017 /* Since a template declaration already existed for this
6018 class-type, we must be redeclaring it here. Make sure
6019 that the redeclaration is valid. */
6021 current_template_parms,
6023 /* We don't need to create a new TEMPLATE_DECL; just use the
6024 one we already had. */
6026 }
6027 else
6028 {
6030 member_template_p);
6035 {
6036 /* A specialization of a member template of a template
6037 class. */
6041 }
6042 }
6043 }
6044 else
6045 {
6051 {
6054 }
6062 {
6063 /* The declaration is a specialization of a member
6064 template, declared outside the class. Therefore, the
6065 innermost template arguments will be NULL, so we
6066 replace them with the arguments determined by the
6067 earlier call to check_explicit_specialization. */
6070 tree new_tmpl
6072 member_template_p);
6080 args,
6083 }
6085 /* Make sure the template headers we got make sense. */
6090 {
6095 }
6096 else
6098 {
6103 {
6107 else
6111 /* Avoid crash in import_export_decl. */
6114 }
6119 /* Can happen in erroneous input. */
6121 else
6123 }
6125 /* Check that the parms are used in the appropriate qualifying scopes
6126 in the declarator. */
6130 {
6136 /* Avoid crash in import_export_decl. */
6139 }
6141 /* Check that the constraints for each enclosing template scope are
6142 consistent with the original declarations. */
6144 {
6148 {
6151 }
6153 {
6155 {
6159 }
6162 }
6163 }
6164 }
6169 {
6170 /* Push template declarations for global functions and types.
6171 Note that we do not try to push a global template friend
6172 declared in a template class; such a thing may well depend on
6173 the template parameters of the class and we'll push it when
6174 instantiating the befriending class. */
6177 {
6182 /* pushdecl may have found an existing template. */
6184 {
6187 }
6188 }
6190 {
6191 /* Record this decl as belonging to the current class. It's
6192 not chained onto anything else. */
6196 }
6197 }
6199 /* The type may have been completed, or (erroneously) changed. */
6203 {
6205 {
6210 /* Give template template parms a DECL_CONTEXT of the template
6211 for which they are a parameter. */
6214 {
6218 }
6222 {
6225 {
6226 /* ??? Why don't we do this here for all templates? */
6229 }
6232 }
6233 }
6235 /* The DECL_TI_ARGS of DECL contains full set of arguments
6236 referring wback to its most general template. If TMPL is a
6237 specialization, ARGS may only have the innermost set of
6238 arguments. Add the missing argument levels if necessary. */
6246 else
6247 {
6250 }
6251 }
6254 && !is_friend
6257 /* Set DECL_COMDAT on template instantiations; if we force
6258 them to be emitted by explicit instantiation,
6259 mark_needed will tell cgraph to do the right thing. */
6265 }
6267 /* FN is an inheriting constructor that inherits from the constructor
6268 template INHERITED; turn FN into a constructor template with a matching
6269 template header. */
6271 tree
6273 {
6274 tree inner_parms
6277 tree parms
6286 }
6288 /* Called when a class template TYPE is redeclared with the indicated
6289 template PARMS, e.g.:
6291 template <class T> struct S;
6292 template <class T> struct S {}; */
6294 bool
6296 {
6297 tree tmpl;
6298 tree tmpl_parms;
6302 {
6305 }
6309 /* The type is nested in some template class. Nothing to worry
6310 about here; there are no new template parameters for the nested
6311 type. */
6315 {
6317 tmpl);
6319 }
6325 {
6335 }
6338 {
6339 tree tmpl_parm;
6340 tree parm;
6352 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
6353 TEMPLATE_DECL. */
6363 {
6364 auto_diagnostic_group d;
6368 else
6371 }
6373 /* The parameters can be declared to introduce different
6374 constraints. */
6378 {
6379 auto_diagnostic_group d;
6385 }
6387 /* Give each template template parm in this redeclaration a
6388 DECL_CONTEXT of the template for which they are a parameter. */
6390 {
6394 }
6395 }
6404 /* Two classes with different constraints declare different entities. */
6406 {
6407 auto_diagnostic_group d;
6413 }
6416 }
6418 /* The actual substitution part of instantiate_non_dependent_expr,
6419 to be used when the caller has already checked
6420 !instantiation_dependent_uneval_expression_p (expr)
6421 and cleared processing_template_decl. */
6423 tree
6425 {
6428 complain,
6430 }
6432 /* Instantiate the non-dependent expression EXPR. */
6434 tree
6437 {
6442 {
6443 /* The caller should have checked this already. */
6445 processing_template_decl_sentinel s;
6447 }
6449 }
6451 /* Like instantiate_non_dependent_expr, but return NULL_TREE if the
6452 expression is dependent or non-constant. */
6454 tree
6456 {
6460 {
6463 else
6464 {
6465 processing_template_decl_sentinel s;
6467 }
6468 }
6470 }
6472 /* True iff T is a specialization of a variable template. */
6474 bool
6476 {
6481 }
6483 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
6484 template declaration, or a TYPE_DECL for an alias declaration. */
6486 bool
6488 {
6496 }
6498 /* If T is a specialization of an alias template, return it; otherwise return
6499 NULL_TREE. If TRANSPARENT_TYPEDEFS is true, look through other aliases. */
6501 tree
6504 {
6508 /* It's an alias template specialization if it's an alias and its
6509 TYPE_NAME is a specialization of a primary template. */
6511 {
6518 transparent_typedefs);
6519 }
6522 }
6524 /* Data structure for complex_alias_template_*. */
6526 struct uses_all_template_parms_data
6527 {
6530 };
6532 /* walk_tree callback for complex_alias_template_p. */
6534 static tree
6536 {
6541 {
6546 {
6550 }
6553 }
6558 /* An alias template with a pack expansion that expands a pack from the
6559 enclosing class needs to be considered complex, to avoid confusion with
6560 the same pack being used as an argument to the alias's own template
6561 parameter (91966). */
6564 {
6573 /* Consider the expanded packs to be used outside the expansion... */
6575 }
6577 /* ...but don't walk into the pattern. Consider PR104008:
6579 template <typename T, typename... Ts>
6580 using IsOneOf = disjunction<is_same<T, Ts>...>;
6582 where IsOneOf seemingly uses all of its template parameters in its
6583 expansion (and does not expand a pack from the enclosing class), so the
6584 alias was not marked as complex. However, if it is used like
6585 "IsOneOf<T>", the empty pack for Ts means that T no longer appears in the
6586 expansion. So only Ts is considered used by the pack expansion. */
6590 }
6592 /* An alias template is complex from a SFINAE perspective if a template-id
6593 using that alias can be ill-formed when the expansion is not, as with
6594 the void_t template.
6596 Returns 1 if always complex, 0 if not complex, -1 if complex iff any of the
6597 template arguments are empty packs. */
6599 static bool
6601 {
6602 /* A renaming alias isn't complex. */
6606 /* Any other constrained alias is complex. */
6625 }
6627 /* If T is a specialization of a complex alias template with dependent
6628 template-arguments, return it; otherwise return NULL_TREE. If T is a
6629 typedef to such a specialization, return the specialization. */
6631 tree
6633 {
6644 && (any_dependent_template_arguments_p
6649 {
6652 }
6655 }
6657 /* Return the number of innermost template parameters in TMPL. */
6659 static int
6661 {
6664 }
6666 /* Return either TMPL or another template that it is equivalent to under DR
6667 1286: An alias that just changes the name of a template is equivalent to
6668 the other template. */
6670 static tree
6672 {
6675 {
6676 /* Determine if the alias is equivalent to an underlying template. */
6678 /* The underlying type may have been ill-formed. Don't proceed. */
6691 /* Does the alias add cv-quals? */
6699 /* Are any default template arguments equivalent? */
6704 {
6709 }
6711 /* If TMPL adds or changes any constraints, it isn't equivalent. I think
6712 it's appropriate to treat a less-constrained alias as equivalent. */
6716 /* Alias is equivalent. Strip it and repeat. */
6718 }
6719 top_break:;
6722 }
6724 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6725 must be a reference-to-function or a pointer-to-function type, as specified
6726 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6727 and check that the resulting function has external linkage. */
6729 static tree
6731 tsubst_flags_t complain)
6732 {
6735 linkage_kind linkage;
6753 /* [temp.arg.nontype]/1
6755 A template-argument for a non-type, non-template template-parameter
6756 shall be one of:
6757 [...]
6758 -- the address of an object or function with external [C++11: or
6759 internal] linkage. */
6763 {
6765 {
6772 else
6775 }
6777 }
6782 {
6784 {
6790 else
6794 }
6796 }
6798 accept:
6800 {
6803 else
6805 }
6810 }
6812 /* Subroutine of convert_nontype_argument.
6813 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6814 Emit an error otherwise. */
6816 static bool
6818 tsubst_flags_t complain)
6819 {
6835 {
6841 else
6843 }
6845 }
6847 /* Returns TRUE iff the address of OP is value-dependent.
6849 14.6.2.4 [temp.dep.temp]:
6850 A non-integral non-type template-argument is dependent if its type is
6851 dependent or it has either of the following forms
6852 qualified-id
6853 & qualified-id
6854 and contains a nested-name-specifier which specifies a class-name that
6855 names a dependent type.
6857 We generalize this to just say that the address of a member of a
6858 dependent class is value-dependent; the above doesn't cover the
6859 address of a static data member named with an unqualified-id. */
6861 static bool
6863 {
6866 /* We could use get_inner_reference here, but there's no need;
6867 this is only relevant for template non-type arguments, which
6868 can only be expressed as &id-expression. */
6870 {
6881 }
6884 }
6886 /* The next set of functions are used for providing helpful explanatory
6887 diagnostics for failed overload resolution. Their messages should be
6888 indented by two spaces for consistency with the messages in
6889 call.cc */
6891 static int
6893 {
6895 }
6897 /* Other failure functions should call this one, to provide a single function
6898 for setting a breakpoint on. */
6900 static int
6902 {
6904 }
6906 static int
6908 {
6913 }
6915 static int
6917 {
6923 }
6925 static int
6927 {
6931 }
6933 static int
6935 {
6938 " template parameter %qD is not a parameter pack, but "
6942 }
6944 static int
6946 {
6949 " template argument %qE does not match "
6953 }
6955 static int
6957 {
6961 }
6963 static int
6965 {
6971 }
6973 static int
6975 {
6977 {
6982 else
6984 " deduced conflicting values for non-type parameter "
6986 }
6988 }
6990 static int
6992 {
6995 " variable-sized array type %qT is not "
6997 arg);
6999 }
7001 static int
7003 {
7007 arg);
7009 }
7011 static int
7013 {
7015 {
7021 else
7026 }
7028 }
7030 static int
7032 {
7034 }
7036 static int
7039 {
7041 }
7043 static int
7046 {
7052 }
7054 static int
7057 {
7060 {
7068 }
7070 }
7072 static int
7074 {
7077 " template parameters of a template template argument are "
7080 }
7082 static int
7084 {
7090 }
7092 static int
7094 {
7099 }
7101 /* Subroutine of convert_nontype_argument, to check whether EXPR, as an
7102 argument for TYPE, points to an unsuitable object.
7104 Also adjust the type of the index in C++20 array subobject references. */
7106 static bool
7108 {
7110 {
7111 CASE_CONVERT:
7113 complain);
7117 complain);
7120 {
7124 }
7128 {
7134 {
7138 /* Canonicalize array offsets to ptrdiff_t; how they were
7139 written doesn't matter for subobject identity. */
7142 }
7145 {
7148 "%qE is not a valid template argument of type %qT "
7152 }
7154 {
7157 "%qE is not a valid template argument of type %qT "
7161 }
7164 {
7167 "%qE is not a valid template argument of type %qT "
7170 }
7171 /* C++17: For a non-type template-parameter of reference or pointer
7172 type, the value of the constant expression shall not refer to (or
7173 for a pointer type, shall not be the address of):
7174 * a subobject (4.5),
7175 * a temporary object (15.2),
7176 * a string literal (5.13.5),
7177 * the result of a typeid expression (8.2.8), or
7178 * a predefined __func__ variable (11.4.1). */
7180 {
7183 decl);
7185 }
7187 && !(same_type_ignoring_top_level_qualifiers_p
7190 {
7195 }
7197 {
7201 decl);
7203 }
7204 }
7212 else
7213 {
7215 {
7218 "because %qD is a variable, not the address of "
7221 }
7222 else
7223 {
7229 }
7230 }
7231 }
7234 }
7236 /* Return a VAR_DECL for the C++20 template parameter object corresponding to
7237 template argument EXPR. */
7239 static tree
7241 {
7246 {
7251 }
7255 /* This is no longer a compound literal. */
7259 }
7261 /* The template arguments corresponding to template parameter objects of types
7262 that contain pointers to members. */
7266 /* Find or build an nttp object for (already-validated) EXPR with name
7267 NAME. */
7269 tree
7271 {
7288 {
7289 /* If EXPR contains any PTRMEM_CST, they will get clobbered by
7290 lower_var_init before we're done mangling. So store the original
7291 value elsewhere. */
7294 }
7299 }
7301 /* Return the actual template argument corresponding to template parameter
7302 object VAR. */
7304 tree
7306 {
7310 }
7312 /* Attempt to convert the non-type template parameter EXPR to the
7313 indicated TYPE. If the conversion is successful, return the
7314 converted value. If the conversion is unsuccessful, return
7315 NULL_TREE if we issued an error message, or error_mark_node if we
7316 did not. We issue error messages for out-and-out bad template
7317 parameters, but not simply because the conversion failed, since we
7318 might be just trying to do argument deduction. Both TYPE and EXPR
7319 must be non-dependent.
7321 The conversion follows the special rules described in
7322 [temp.arg.nontype], and it is much more strict than an implicit
7323 conversion.
7325 This function is called twice for each template argument (see
7326 lookup_template_class for a more accurate description of this
7327 problem). This means that we need to handle expressions which
7328 are not valid in a C++ source, but can be created from the
7329 first call (for instance, casts to perform conversions). These
7330 hacks can go away after we fix the double coercion problem. */
7332 static tree
7334 {
7335 tree expr_type;
7338 /* Detect immediately string literals as invalid non-type argument.
7339 This special-case is not needed for correctness (we would easily
7340 catch this later), but only to provide better diagnostic for this
7341 common user mistake. As suggested by DR 100, we do not mention
7342 linkage issues in the diagnostic as this is not the point. */
7344 {
7350 }
7352 /* Add the ADDR_EXPR now for the benefit of
7353 value_dependent_expression_p. */
7356 {
7360 }
7362 /* If we are in a template, EXPR may be non-dependent, but still
7363 have a syntactic, rather than semantic, form. For example, EXPR
7364 might be a SCOPE_REF, rather than the VAR_DECL to which the
7365 SCOPE_REF refers. Preserving the qualifying scope is necessary
7366 so that access checking can be performed when the template is
7367 instantiated -- but here we need the resolved form so that we can
7368 convert the argument. */
7380 /* If the argument is non-dependent, perform any conversions in
7381 non-dependent context as well. */
7389 else
7392 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
7393 to a non-type argument of "nullptr". */
7397 /* In C++11, integral or enumeration non-type template arguments can be
7398 arbitrary constant expressions. Pointer and pointer to
7399 member arguments can be general constant expressions that evaluate
7400 to a null value, but otherwise still need to be of a specific form. */
7402 {
7404 /* A PTRMEM_CST is already constant, and a valid template
7405 argument for a parameter of pointer to member type, we just want
7406 to leave it in that form rather than lower it to a
7410 {
7411 /* C++17: A template-argument for a non-type template-parameter shall
7412 be a converted constant expression (8.20) of the type of the
7413 template-parameter. */
7416 /* Make sure we return NULL_TREE only if we have really issued
7417 an error, as described above. */
7420 {
7423 }
7426 /* EXPR may have become value-dependent. */
7428 }
7430 {
7435 }
7436 }
7440 else
7443 /* HACK: Due to double coercion, we can get a
7444 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
7445 which is the tree that we built on the first call (see
7446 below when coercing to reference to object or to reference to
7447 function). We just strip everything and get to the arg.
7448 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
7449 for examples. */
7451 {
7452 /* Check this before we strip *& to avoid redundancy. */
7461 {
7462 /* ??? Maybe we could use convert_from_reference here, but we
7463 would need to relax its constraints because the NOP_EXPR
7464 could actually change the type to something more cv-qualified,
7465 and this is not folded by convert_from_reference. */
7470 && (same_type_ignoring_top_level_qualifiers_p
7473 {
7476 }
7477 }
7478 }
7480 /* [temp.arg.nontype]/5, bullet 1
7482 For a non-type template-parameter of integral or enumeration type,
7483 integral promotions (_conv.prom_) and integral conversions
7484 (_conv.integral_) are applied. */
7487 {
7489 {
7494 }
7499 /* Notice that there are constant expressions like '4 % 0' which
7500 do not fold into integer constants. */
7502 {
7504 {
7508 else
7514 /* else cxx_constant_value complained but gave us
7515 a real constant, so go ahead. */
7517 {
7518 /* Some assemble time constant expressions like
7519 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
7520 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
7521 as we can emit them into .rodata initializers of
7522 variables, yet they can't fold into an INTEGER_CST at
7523 compile time. Refuse them here. */
7528 }
7529 }
7530 else
7532 }
7534 /* Avoid typedef problems. */
7537 }
7538 /* [temp.arg.nontype]/5, bullet 2
7540 For a non-type template-parameter of type pointer to object,
7541 qualification conversions (_conv.qual_) and the array-to-pointer
7542 conversion (_conv.array_) are applied. */
7544 {
7547 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
7548 decay_conversion or an explicit cast. If it's a problematic cast,
7549 we'll complain about it below. */
7551 {
7556 {
7559 }
7560 }
7562 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
7564 A template-argument for a non-type, non-template template-parameter
7565 shall be one of: [...]
7567 -- the name of a non-type template-parameter;
7568 -- the address of an object or function with external linkage, [...]
7569 expressed as "& id-expression" where the & is optional if the name
7570 refers to a function or array, or if the corresponding
7571 template-parameter is a reference.
7573 Here, we do not care about functions, as they are invalid anyway
7574 for a parameter of type pointer-to-object. */
7577 /* Non-type template parameters are OK. */
7578 ;
7583 /* Other values, like integer constants, might be valid
7584 non-type arguments of some other type. */
7594 }
7595 /* [temp.arg.nontype]/5, bullet 3
7597 For a non-type template-parameter of type reference to object, no
7598 conversions apply. The type referred to by the reference may be more
7599 cv-qualified than the (otherwise identical) type of the
7600 template-argument. The template-parameter is bound directly to the
7601 template-argument, which must be an lvalue. */
7603 {
7605 expr_type))
7609 {
7614 }
7617 {
7622 }
7624 /* [temp.arg.nontype]/1
7626 A template-argument for a non-type, non-template template-parameter
7627 shall be one of: [...]
7629 -- the address of an object or function with external linkage. */
7632 {
7635 {
7638 "because a reference variable does not have a constant "
7641 }
7642 }
7645 /* OK, dependent reference. We don't want to ask whether a DECL is
7647 else
7648 {
7653 }
7657 }
7658 /* [temp.arg.nontype]/5, bullet 4
7660 For a non-type template-parameter of type pointer to function, only
7661 the function-to-pointer conversion (_conv.func_) is applied. If the
7662 template-argument represents a set of overloaded functions (or a
7663 pointer to such), the matching function is selected from the set
7664 (_over.over_). */
7666 {
7667 /* If the argument is a template-id, we might not have enough
7668 context information to decay the pointer. */
7670 {
7674 }
7677 /* Null pointer values are OK in C++11. */
7683 }
7684 /* [temp.arg.nontype]/5, bullet 5
7686 For a non-type template-parameter of type reference to function, no
7687 conversions apply. If the template-argument represents a set of
7688 overloaded functions, the matching function is selected from the set
7689 (_over.over_). */
7691 {
7693 {
7695 {
7700 }
7702 }
7707 }
7708 /* [temp.arg.nontype]/5, bullet 6
7710 For a non-type template-parameter of type pointer to member function,
7711 no conversions apply. If the template-argument represents a set of
7712 overloaded member functions, the matching member function is selected
7713 from the set (_over.over_). */
7715 {
7720 /* [temp.arg.nontype] bullet 1 says the pointer to member
7721 expression must be a pointer-to-member constant. */
7726 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
7727 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
7730 }
7731 /* [temp.arg.nontype]/5, bullet 7
7733 For a non-type template-parameter of type pointer to data member,
7734 qualification conversions (_conv.qual_) are applied. */
7736 {
7737 /* [temp.arg.nontype] bullet 1 says the pointer to member
7738 expression must be a pointer-to-member constant. */
7746 }
7748 {
7750 {
7755 }
7757 }
7759 {
7760 /* Replace the argument with a reference to the corresponding template
7761 parameter object. */
7766 }
7767 /* A template non-type parameter must be one of the above. */
7768 else
7771 /* Sanity check: did we actually convert the argument to the
7772 right type? */
7776 }
7778 /* Subroutine of coerce_template_template_parms, which returns 1 if
7779 PARM_PARM and ARG_PARM match using the rule for the template
7780 parameters of template template parameters. Both PARM and ARG are
7781 template parameters; the rest of the arguments are the same as for
7782 coerce_template_template_parms.
7783 */
7784 static int
7786 tree arg,
7787 tsubst_flags_t complain,
7788 tree in_decl,
7789 tree outer_args)
7790 {
7799 {
7801 /* We encounter instantiations of templates like
7802 template <template <template <class> class> class TT>
7803 class C; */
7804 {
7808 }
7809 /* Fall through. */
7814 /* Argument is a parameter pack but parameter is not. */
7819 /* The tsubst call is used to handle cases such as
7821 template <int> class C {};
7822 template <class T, template <T> class TT> class D {};
7823 D<int, C> d;
7825 i.e. the parameter list of TT depends on earlier parameters. */
7827 {
7832 }
7836 /* Argument is a parameter pack but parameter is not. */
7843 }
7846 }
7848 /* Coerce template argument list ARGLIST for use with template
7849 template-parameter TEMPL. */
7851 static tree
7853 tsubst_flags_t complain)
7854 {
7855 /* Consider an example where a template template parameter declared as
7857 template <class T, class U = std::allocator<T> > class TT
7859 The template parameter level of T and U are one level larger than
7860 of TT. To proper process the default argument of U, say when an
7861 instantiation `TT<int>' is seen, we need to build the full
7862 arguments containing {int} as the innermost level. Outer levels,
7863 available when not appearing as default template argument, can be
7864 obtained from the arguments of the enclosing template.
7866 Suppose that TT is later substituted with std::vector. The above
7867 instantiation is `TT<int, std::allocator<T> >' with TT at
7868 level 1, and T at level 2, while the template arguments at level 1
7869 becomes {std::vector} and the inner level 2 is {int}. */
7875 {
7876 /* This is an argument of the current template, so we haven't set
7877 DECL_CONTEXT yet. We can also get here when level-lowering a
7878 bound ttp. */
7879 tree relevant_template_parms;
7881 /* Parameter levels that are greater than the level of the given
7882 template template parm are irrelevant. */
7889 }
7896 }
7898 /* A cache of template template parameters with match-all default
7899 arguments. */
7902 /* T is a bound template template-parameter. Copy its arguments into default
7903 arguments of the template template-parameter's template parameters. */
7905 static tree
7907 {
7930 {
7933 {
7936 }
7937 }
7941 }
7943 /* ARG is a bound potential template template-argument, and PARGS is a list
7944 of arguments for the corresponding template template-parameter. Adjust
7945 PARGS as appropriate for application to ARG's template, and if ARG is a
7946 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7947 arguments to the template template parameter. */
7949 static tree
7951 {
7955 {
7956 /* When comparing two template template-parameters in partial ordering,
7957 rewrite the one currently being used as an argument to have default
7958 arguments for all parameters. */
7964 }
7965 else
7966 {
7967 tree aparms
7970 }
7973 }
7975 /* Subroutine of unify for the case when PARM is a
7976 BOUND_TEMPLATE_TEMPLATE_PARM. */
7978 static int
7981 {
7985 /* The template template parm might be variadic and the argument
7986 not, so flatten both argument lists. */
7991 {
7992 /* In keeping with P0522R0, adjust P's template arguments
7993 to apply to A's template; then flatten it again. */
8001 /* If the P0522 adjustment eliminated a pack expansion, deduce
8002 empty packs. */
8008 }
8009 else
8010 {
8011 /* Deduce arguments T, i from TT<T> or TT<i>.
8012 We check each element of PARMVEC and ARGVEC individually
8013 rather than the whole TREE_VEC since they can have
8014 different number of elements, which is allowed under N2555. */
8018 /* Check if the parameters end in a pack, making them
8019 variadic. */
8026 /* If the template argument list of P contains a pack
8027 expansion that is not the last template argument, the
8028 entire template argument list is a non-deduced
8029 context. */
8047 DEDUCE_EXACT,
8050 }
8053 }
8055 /* Return 1 if PARM_TMPL and ARG_TMPL match using rule for
8056 template template parameters.
8058 Consider the example:
8059 template <class T> class A;
8060 template<template <class U> class TT> class B;
8062 For B<A>, PARM_TMPL is TT, while ARG_TMPL is A,
8063 and OUTER_ARGS contains A. */
8065 static int
8067 tree arg_tmpl,
8068 tsubst_flags_t complain,
8069 tree in_decl,
8070 tree outer_args)
8071 {
8087 {
8088 /* P0522R0: A template template-parameter P is at least as specialized as
8089 a template template-argument A if, given the following rewrite to two
8090 function templates, the function template corresponding to P is at
8091 least as specialized as the function template corresponding to A
8092 according to the partial ordering rules for function templates
8093 ([temp.func.order]). Given an invented class template X with the
8094 template parameter list of A (including default arguments):
8096 * Each of the two function templates has the same template parameters,
8097 respectively, as P or A.
8099 * Each function template has a single function parameter whose type is
8100 a specialization of X with template arguments corresponding to the
8101 template parameters from the respective function template where, for
8102 each template parameter PP in the template parameter list of the
8103 function template, a corresponding template argument AA is formed. If
8104 PP declares a parameter pack, then AA is the pack expansion
8105 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
8107 If the rewrite produces an invalid type, then P is not at least as
8108 specialized as A. */
8110 /* So coerce P's args to apply to A's parms, and then deduce between A's
8111 args and the converted args. If that succeeds, A is at least as
8112 specialized as P, so they match.*/
8118 /* PARM and ARG might be at different template depths, and we want to
8119 pass the right additional levels of args when coercing PARGS to
8120 ARG_PARMS in case we need to do any substitution into non-type
8121 template parameter types.
8123 OUTER_ARGS are not the right outer levels in this case, as they are
8124 the args we're building up for PARM, and for the coercion we want the
8125 args for ARG. If DECL_CONTEXT isn't set for a template template
8126 parameter, we can assume that it's in the current scope. In that case
8127 we might end up adding more levels than needed, but that shouldn't be
8128 a problem; any args we need to refer to are at the right level. */
8139 {
8145 }
8146 }
8148 /* Determine whether we have a parameter pack at the end of the
8149 template template parameter's template parameter list. */
8151 {
8158 {
8172 }
8173 }
8179 /* Check all of the template parameters except the parameter pack at
8180 the end (if any). */
8182 {
8191 outer_args))
8194 }
8197 {
8198 /* Check each of the template parameters in the template
8199 argument against the template parameter pack at the end of
8200 the template template parameter. */
8207 {
8214 outer_args))
8216 }
8217 }
8220 }
8222 /* Verifies that the deduced template arguments (in TARGS) for the
8223 template template parameters (in TPARMS) represent valid bindings,
8224 by comparing the template parameter list of each template argument
8225 to the template parameter list of its corresponding template
8226 template parameter, in accordance with DR150. This
8227 routine can only be called after all template arguments have been
8228 deduced. It will return TRUE if all of the template template
8229 parameter bindings are okay, FALSE otherwise. */
8230 bool
8232 {
8236 /* We're dealing with template parms in this process. */
8242 {
8247 {
8252 {
8253 /* Look inside the argument pack. */
8256 }
8259 {
8261 /* Extract the next argument from the argument
8262 pack. */
8266 /* Look at the pattern of the pack expansion. */
8269 /* Extract the template parameters from the template
8270 argument. */
8274 /* Verify that we can coerce the template template
8275 parameters from the template argument to the template
8276 parameter. This requires an exact match. */
8278 && !coerce_template_template_parms
8280 targ,
8281 tf_none,
8282 tparm,
8283 targs))
8284 {
8287 }
8288 }
8289 }
8290 }
8292 out:
8296 }
8298 /* Since type attributes aren't mangled, we need to strip them from
8299 template type arguments. */
8301 tree
8303 {
8313 }
8315 /* And from inside dependent non-type arguments like sizeof(Type). */
8317 static tree
8319 {
8329 }
8331 /* A template declaration can be substituted for a constrained
8332 template template parameter only when the argument is no more
8333 constrained than the parameter. */
8335 static bool
8337 {
8340 /* For now, allow constrained template template arguments
8341 and unconstrained template template parameters. */
8345 /* If the template parameter is constrained, we need to rewrite its
8346 constraints in terms of the ARG's template parameters. This ensures
8347 that all of the template parameter types will have the same depth.
8349 Note that this is only valid when coerce_template_template_parm is
8350 true for the innermost template parameters of PARM and ARG. In other
8351 words, because coercion is successful, this conversion will be valid. */
8354 {
8363 }
8366 }
8368 // Convert a placeholder argument into a binding to the original
8369 // parameter. The original parameter is saved as the TREE_TYPE of
8370 // ARG.
8373 {
8376 }
8378 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
8379 because one of them is dependent. But we need to represent the
8380 conversion for the benefit of cp_tree_equal. */
8382 static tree
8384 {
8385 /* Auto parms get no conversion. */
8388 /* We don't need or want to add this conversion now if we're going to use the
8389 argument for deduction. */
8401 }
8403 /* Convert the indicated template ARG as necessary to match the
8404 indicated template PARM. Returns the converted ARG, or
8405 error_mark_node if the conversion was unsuccessful. Error and
8406 warning messages are issued under control of COMPLAIN. This
8407 conversion is for the Ith parameter in the parameter list. ARGS is
8408 the full set of template arguments deduced so far. */
8410 static tree
8412 tree arg,
8413 tree args,
8414 tsubst_flags_t complain,
8416 tree in_decl)
8417 {
8418 tree orig_arg;
8419 tree val;
8425 /* Trivially convert placeholders. */
8434 {
8435 /* The template argument was the name of some
8436 member function. That's usually
8437 invalid, but static members are OK. In any
8438 case, grab the underlying fields/functions
8439 and issue an error later if required. */
8441 }
8449 /* When determining whether an argument pack expansion is a template,
8450 look at the pattern. */
8454 /* Deal with an injected-class-name used as a template template arg. */
8456 {
8459 {
8469 }
8470 }
8472 is_tmpl_type =
8488 {
8490 {
8494 }
8497 "to refer to a type member of a template parameter, "
8502 typename_type,
8503 complain);
8506 }
8508 {
8510 {
8512 {
8517 {
8518 /* The template argument is a type, but we're expecting
8519 an expression. */
8524 /* [temp.arg]/2: "In a template-argument, an ambiguity
8525 between a type-id and an expression is resolved to a
8526 type-id, regardless of the form of the corresponding
8527 template-parameter." So give the user a clue. */
8530 "for non-type template parameter is treated as "
8532 }
8536 else
8539 }
8540 }
8542 }
8544 {
8546 {
8553 else
8556 }
8558 }
8561 /* We already did the appropriate conversion when packing args. */
8564 {
8566 {
8568 /* The number of argument required is not known yet.
8569 Just accept it for now. */
8571 else
8572 {
8573 /* Strip alias templates that are equivalent to another
8574 template. */
8579 args))
8580 {
8583 /* TEMPLATE_TEMPLATE_PARM node is preferred over
8584 TEMPLATE_DECL. */
8586 {
8591 }
8592 }
8593 else
8594 {
8596 {
8603 }
8606 }
8608 // Check that the constraints are compatible before allowing the
8609 // substitution.
8612 {
8614 {
8620 }
8622 }
8623 }
8624 }
8625 else
8627 /* We only form one instance of each template specialization.
8628 Therefore, if we use a non-canonical variant (i.e., a
8629 typedef), any future messages referring to the type will use
8630 the typedef, which is confusing if those future uses do not
8631 themselves also use the typedef. */
8634 }
8635 else
8636 {
8641 /* We don't have enough levels of args to do any substitution. This
8644 {
8649 }
8650 else
8653 /* Perform array-to-pointer and function-to-pointer conversion
8654 as per [temp.param]/10. */
8660 /* Drop top-level cv-qualifiers on the substituted/deduced type of
8661 this non-type template parameter, as per [temp.param]/6. */
8669 /* We used to call digest_init here. However, digest_init
8670 will report errors, which we don't want when complain
8671 is zero. More importantly, digest_init will try too
8672 hard to convert things: for example, `0' should not be
8673 converted to pointer type at this point according to
8674 the standard. Accepting this is not merely an
8675 extension, since deciding whether or not these
8676 conversions can occur is part of determining which
8677 function template to call, or whether a given explicit
8678 argument specification is valid. */
8680 else
8681 {
8684 }
8695 {
8696 /* Reject template arguments that are references to built-in
8697 functions with no library fallbacks. */
8706 }
8709 {
8710 /* Strip typedefs from the SCOPE_REF. */
8713 complain);
8716 }
8717 }
8720 }
8722 /* Coerces the remaining template arguments in INNER_ARGS (from
8723 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
8724 Returns the coerced argument pack. PARM_IDX is the position of this
8725 parameter in the template parameter list. ARGS is the original
8726 template argument list. */
8727 static tree
8730 tree args,
8731 tree inner_args,
8733 tree new_args,
8735 tree in_decl,
8736 tsubst_flags_t complain)
8737 {
8740 tree packed_args;
8741 tree argument_pack;
8748 {
8749 /* When the template parameter is a non-type template parameter pack
8750 or template template parameter pack whose type or template
8751 parameters use parameter packs, we know exactly how many arguments
8752 we are looking for. Build a vector of the instantiated decls for
8753 these template parameters in PACKED_PARMS. */
8754 /* We can't use make_pack_expansion here because it would interpret a
8755 _DECL as a use rather than a declaration. */
8769 /* If we're doing a partial instantiation of a member template,
8770 verify that all of the types used for the non-type
8771 template parameter pack are, in fact, valid for non-type
8772 template parameters. */
8775 {
8778 {
8783 }
8784 /* We don't know how many args we have yet, just
8785 use the unconverted ones for now. */
8787 }
8790 }
8791 /* Check if we have a placeholder pack, which indicates we're
8792 in the context of a introduction list. In that case we want
8793 to match this pack to the single placeholder. */
8797 {
8800 }
8801 else
8804 /* Convert the remaining arguments, which will be a part of the
8805 parameter pack "parm". */
8808 {
8814 {
8815 /* Once we've packed as many args as we have types, stop. */
8819 /* We don't know how many args we have yet, just
8820 use the unconverted ones for now. */
8822 else
8824 }
8827 {
8830 }
8831 else
8834 in_decl);
8838 }
8842 {
8847 }
8852 else
8853 {
8856 }
8863 }
8865 /* Returns the number of pack expansions in the template argument vector
8866 ARGS. */
8868 static int
8870 {
8875 {
8879 }
8881 }
8883 /* Convert all template arguments to their appropriate types, and
8884 return a vector containing the innermost resulting template
8885 arguments. If any error occurs, return error_mark_node. Error and
8886 warning messages are issued under control of COMPLAIN.
8888 If PARMS represents all template parameters levels, this function
8889 returns a vector of vectors representing all the resulting argument
8890 levels. Note that in this case, only the innermost arguments are
8891 coerced because the outermost ones are supposed to have been coerced
8892 already. Otherwise, if PARMS represents only (the innermost) vector
8893 of parameters, this function returns a vector containing just the
8894 innermost resulting arguments.
8896 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8897 for arguments not specified in ARGS. If REQUIRE_ALL_ARGS is true,
8898 arguments not specified in ARGS must have default arguments which
8899 we'll use to fill in ARGS. */
8901 tree
8903 tree args,
8904 tree in_decl,
8905 tsubst_flags_t complain,
8907 {
8909 tree orig_inner_args;
8910 tree inner_args;
8912 /* When used as a boolean value, indicates whether this is a
8913 variadic template parameter list. Since it's an int, we can also
8914 subtract it from nparms to get the number of non-variadic
8915 parameters. */
8920 /* Adjustment to nparms for fixed parameter packs. */
8925 /* Likewise for parameters with default arguments. */
8933 {
8935 {
8938 }
8940 }
8944 /* Determine if there are any parameter packs or default arguments. */
8946 {
8954 }
8957 /* If there are no parameters that follow a parameter pack, we need to
8958 expand any argument packs so that we can deduce a parameter pack from
8959 some non-packed args followed by an argument pack, as in variadic85.C.
8960 If there are such parameters, we need to leave argument packs intact
8961 so the arguments are assigned properly. This can happen when dealing
8962 with a nested class inside a partial specialization of a class
8963 template, as in variadic92.C, or when deducing a template parameter pack
8964 from a sub-declarator, as in variadic114.C. */
8968 /* Count any pack expansion args. */
8974 && require_all_args
8975 && !variadic_args_p
8978 {
8979 bad_nargs:
8981 {
8983 {
8987 }
8988 else
8995 }
8998 }
8999 /* We can't pass a pack expansion to a non-pack parameter of an alias
9000 template (DR 1430). */
9004 && variadic_args_p
9006 {
9008 {
9010 {
9016 {
9019 "pack expansion argument for non-pack parameter "
9021 else
9023 "pack expansion argument for non-pack parameter "
9027 }
9028 }
9030 found:;
9031 }
9033 }
9035 /* We need to evaluate the template arguments, even though this
9036 template-id may be nested within a "sizeof". */
9037 cp_evaluated ev;
9043 {
9044 tree arg;
9045 tree parm;
9047 /* Get the Ith template parameter. */
9051 {
9054 }
9056 /* Calculate the next argument. */
9059 else
9065 {
9066 /* Some arguments will be placed in the
9067 template parameter pack PARM. */
9074 {
9075 /* We don't know how many args we have yet, just use the
9076 unconverted (and still packed) ones for now. */
9080 }
9084 /* Store this argument. */
9086 {
9087 lost++;
9088 /* We are done with all of the arguments. */
9091 }
9092 else
9093 {
9097 {
9100 }
9101 }
9104 }
9106 {
9108 {
9109 /* "If every valid specialization of a variadic template
9110 requires an empty template parameter pack, the template is
9111 ill-formed, no diagnostic required." So check that the
9112 pattern works with this parameter. */
9117 in_decl);
9119 {
9124 }
9126 /* Recover from missing typename. */
9130 /* We don't know how many args we have yet, just
9131 use the unconverted ones for now. */
9135 }
9136 }
9138 {
9139 /* There must be a default arg in this case. */
9142 /* The position of the first default template argument,
9143 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
9144 Record that. */
9148 }
9149 else
9153 {
9156 }
9158 {
9159 /* This can occur if there was an error in the template
9160 parameter list itself (which we would already have
9161 reported) that we are trying to recover from, e.g., a class
9162 template with a parameter list such as
9163 template<typename..., typename> (cpp0x/variadic150.C). */
9166 /* This can also happen with a fixed parameter pack (71834). */
9169 }
9170 else
9176 lost++;
9179 }
9182 {
9183 /* If we had fixed parameter packs, we didn't know how many arguments we
9184 actually needed earlier; now we do. */
9188 }
9191 {
9192 /* We had some pack expansion arguments that will only work if the packs
9193 are empty, but wait until instantiation time to complain.
9194 See variadic-ttp3.C. */
9196 /* Except that we can't provide empty packs to alias templates or
9197 concepts when there are no corresponding parameters. Basically,
9198 we can get here with this:
9200 template<typename T> concept C = true;
9202 template<typename... Args>
9203 requires C<Args...>
9204 void f();
9206 When parsing C<Args...>, we try to form a concept check of
9207 C<?, Args...>. Without the extra check for substituting an empty
9208 pack past the last parameter, we can accept the check as valid.
9210 FIXME: This may be valid for alias templates (but I doubt it).
9212 FIXME: The error could be better also. */
9214 {
9219 }
9230 }
9233 {
9236 }
9243 }
9245 /* Returns true if T is a wrapper to make a C++20 template parameter
9246 object const. */
9248 static bool
9250 {
9256 }
9258 /* Returns 1 if template args OT and NT are equivalent. */
9260 int
9262 {
9275 /* DR 1558: Don't treat an alias template specialization with dependent
9276 arguments as equivalent to its underlying type when used as a template
9277 argument; we need them to be distinct so that we substitute into the
9278 specialization arguments at instantiation time. And aliases can't be
9279 equivalent without being ==, so we don't need to look any deeper.
9281 During partial ordering, however, we need to treat them normally so we can
9282 order uses of the same alias with different cv-qualification (79960). */
9288 /* For member templates */
9301 {
9305 }
9306 else
9307 {
9308 /* Try to treat a template non-type argument that has been converted
9309 to the parameter type as equivalent to one that hasn't yet. */
9323 }
9324 }
9326 /* Returns true iff the OLDARGS and NEWARGS are in fact identical sets of
9327 template arguments. Returns false otherwise, and updates OLDARG_PTR and
9328 NEWARG_PTR with the offending arguments if they are non-NULL. */
9330 bool
9334 {
9345 {
9350 {
9356 }
9357 }
9359 }
9363 {
9365 }
9367 /* Implement a freelist interface for objects of type T.
9369 Head is a separate object, rather than a regular member, so that we
9370 can define it as a GTY deletable pointer, which is highly
9371 desirable. A data member could be declared that way, but then the
9372 containing object would implicitly get GTY((user)), which would
9373 prevent us from instantiating freelists as global objects.
9374 Although this way we can create freelist global objects, they're
9375 such thin wrappers that instantiating temporaries at every use
9376 loses nothing and saves permanent storage for the freelist object.
9378 Member functions next, anew, poison and reinit have default
9379 implementations that work for most of the types we're interested
9380 in, but if they don't work for some type, they should be explicitly
9381 specialized. See the comments before them for requirements, and
9382 the example specializations for the tree_list_freelist. */
9384 class freelist
9385 {
9386 /* Return the next object in a chain. We could just do type
9387 punning, but if we access the object with its underlying type, we
9388 avoid strict-aliasing trouble. This needs only work between
9389 poison and reinit. */
9392 /* Return a newly allocated, uninitialized or minimally-initialized
9393 object of type T. Any initialization performed by anew should
9394 either remain across the life of the object and the execution of
9395 poison, or be redone by reinit. */
9398 /* Optionally scribble all over the bits holding the object, so that
9399 they become (mostly?) uninitialized memory. This is called while
9400 preparing to make the object part of the free list. */
9405 #ifdef ENABLE_GC_CHECKING
9406 /* Poison the data, to indicate the data is garbage. */
9409 #endif
9410 /* Let valgrind know the object is free. */
9413 /* Let valgrind know the next portion of the object is available,
9414 but uninitialized. */
9416 }
9418 /* Bring an object that underwent at least one lifecycle after anew
9419 and before the most recent free and poison, back to a usable
9420 state, reinitializing whatever is needed for it to be
9421 functionally equivalent to an object just allocated and returned
9422 by anew. This may poison or clear the next field, used by
9423 freelist housekeeping after poison was called. */
9427 #ifdef ENABLE_GC_CHECKING
9429 #endif
9430 /* Let valgrind know the entire object is available, but
9431 uninitialized. */
9433 }
9435 /* Reference a GTY-deletable pointer that points to the first object
9436 in the free list proper. */
9439 /* Construct a freelist object chaining objects off of HEAD. */
9442 /* Add OBJ to the free object list. The former head becomes OBJ's
9443 successor. */
9445 {
9449 }
9451 /* Take an object from the free list, if one is available, or
9452 allocate a new one. Objects taken from the free list should be
9453 regarded as filled with garbage, except for bits that are
9454 configured to be preserved across free and alloc. */
9456 {
9458 {
9463 }
9464 else
9466 }
9467 };
9469 /* Explicitly specialize the interfaces for freelist<tree_node>: we
9470 want to allocate a TREE_LIST using the usual interface, and ensure
9471 TREE_CHAIN remains functional. Alas, we have to duplicate a bit of
9472 build_tree_list logic in reinit, so this could go out of sync. */
9476 {
9478 }
9480 inline tree
9482 {
9484 }
9488 {
9494 #ifdef ENABLE_GC_CHECKING
9497 /* Poison the data, to indicate the data is garbage. */
9500 #endif
9501 /* Let valgrind know the object is free. */
9503 /* But we still want to use the TREE_CODE and TREE_CHAIN parts. */
9507 #ifdef ENABLE_GC_CHECKING
9509 /* Keep TREE_CHAIN functional. */
9511 #else
9513 #endif
9514 }
9518 {
9521 #ifdef ENABLE_GC_CHECKING
9525 #endif
9527 /* Let valgrind know the entire object is available, but
9528 uninitialized. */
9531 #ifdef ENABLE_GC_CHECKING
9533 #else
9535 #endif
9536 }
9538 /* Point to the first object in the TREE_LIST freelist. */
9540 /* Return the/an actual TREE_LIST freelist. */
9543 {
9545 }
9547 /* Point to the first object in the tinst_level freelist. */
9549 /* Return the/an actual tinst_level freelist. */
9552 {
9554 }
9556 /* Point to the first object in the pending_template freelist. */
9558 /* Return the/an actual pending_template freelist. */
9561 {
9563 }
9565 /* Build the TREE_LIST object out of a split list, store it
9566 permanently, and return it. */
9567 tree
9569 {
9578 }
9582 /* Increment OBJ's refcount unless it is already infinite. */
9585 {
9589 }
9591 /* Release storage for OBJ and node, if it's a TREE_LIST. */
9592 void
9594 {
9598 }
9600 /* Decrement OBJ's refcount if not infinite. If it reaches zero, release
9601 OBJ's DECL and OBJ, and start over with the tinst_level object that
9602 used to be referenced by OBJ's NEXT. */
9603 static void
9605 {
9609 {
9613 }
9614 }
9616 /* Modify PTR so that it points to OBJ, adjusting the refcounts of OBJ
9617 and of the former PTR. Omitting the second argument is equivalent
9618 to passing (T*)NULL; this is allowed because passing the
9619 zero-valued integral constant NULL confuses type deduction and/or
9620 overload resolution. */
9622 static void
9624 {
9628 }
9630 static void
9632 {
9642 /* We are called both from instantiate_decl, where we've already had a
9643 tinst_level pushed, and instantiate_template, where we haven't.
9644 Compensate. */
9646 level = !current_tinst_level
9658 else
9667 }
9670 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
9671 ARGLIST. Valid choices for FNS are given in the cp-tree.def
9672 documentation for TEMPLATE_ID_EXPR. */
9674 tree
9676 {
9683 {
9686 }
9689 {
9692 unknown_type_node,
9694 arglist);
9696 }
9699 }
9701 /* Within the scope of a template class S<T>, the name S gets bound
9702 (in build_self_reference) to a TYPE_DECL for the class, not a
9703 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
9704 or one of its enclosing classes, and that type is a template,
9705 return the associated TEMPLATE_DECL. Otherwise, the original
9706 DECL is returned.
9708 Also handle the case when DECL is a TREE_LIST of ambiguous
9709 injected-class-names from different bases. */
9711 tree
9713 {
9717 /* DR 176: A lookup that finds an injected-class-name (10.2
9718 [class.member.lookup]) can result in an ambiguity in certain cases
9719 (for example, if it is found in more than one base class). If all of
9720 the injected-class-names that are found refer to specializations of
9721 the same class template, and if the name is followed by a
9722 template-argument-list, the reference refers to the class template
9723 itself and not a specialization thereof, and is not ambiguous. */
9725 {
9728 {
9734 }
9737 else
9739 }
9745 }
9747 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
9748 parameters, find the desired type.
9750 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
9752 IN_DECL, if non-NULL, is the template declaration we are trying to
9753 instantiate.
9755 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
9756 the class we are looking up.
9758 Issue error and warning messages under control of COMPLAIN.
9760 If the template class is really a local class in a template
9761 function, then the FUNCTION_CONTEXT is the function in which it is
9762 being instantiated.
9764 ??? Note that this function is currently called *twice* for each
9765 template-id: the first time from the parser, while creating the
9766 incomplete type (finish_template_type), and the second type during the
9767 real instantiation (instantiate_template_class). This is surely something
9768 that we want to avoid. It also causes some problems with argument
9769 coercion (see convert_nontype_argument for more information on this). */
9771 tree
9774 {
9778 tree t;
9781 spec_entry elt;
9782 hashval_t hash;
9785 {
9789 else
9790 {
9797 }
9798 }
9800 {
9803 /* If we are declaring a constructor, say A<T>::A<T>, we will get
9804 an implicit typename for the second A. Deal with it. */
9809 {
9812 }
9813 }
9816 {
9819 }
9821 {
9824 }
9826 {
9829 }
9831 /* Issue an error message if we didn't find a template. */
9833 {
9837 }
9840 /* Make sure it's a user visible template, if it was named by
9841 the user. */
9844 {
9846 {
9850 }
9852 }
9856 /* An alias that just changes the name of a template is equivalent to the
9857 other template, so if any of the arguments are pack expansions, strip
9858 the alias to avoid problems with a pack expansion passed to a non-pack
9859 alias template parameter (DR 1430). */
9864 {
9865 tree parm;
9874 }
9875 else
9876 {
9878 tree gen_tmpl;
9879 tree type_decl;
9887 /* An error occurred while building the template TEMPL, and a
9888 diagnostic has most certainly been emitted for that
9889 already. Let's propagate that error. */
9901 {
9902 /* We've been given an incomplete set of template arguments.
9903 For example, given:
9905 template <class T> struct S1 {
9906 template <class U> struct S2 {};
9907 template <class U> struct S2<U*> {};
9908 };
9910 we will be called with an ARGLIST of `U*', but the
9911 TEMPLATE will be `template <class T> template
9912 <class U> struct S1<T>::S2'. We must fill in the missing
9913 arguments. */
9917 }
9919 /* Now we should have enough arguments. */
9922 /* From here on, we're only interested in the most general
9923 template. */
9925 /* Shortcut looking up the current class scope again. */
9929 {
9940 }
9942 /* Calculate the BOUND_ARGS. These will be the args that are
9943 actually tsubst'd into the definition to create the
9944 instantiation. */
9949 /* We were unable to bind the arguments. */
9952 /* In the scope of a template class, explicit references to the
9953 template class refer to the type of the template, not any
9954 instantiation of it. For example, in:
9956 template <class T> class C { void f(C<T>); }
9958 the `C<T>' is just the same as `C'. Outside of the
9959 class, however, such a reference is an instantiation. */
9963 {
9968 }
9970 /* If we already have this specialization, return it. */
9980 /* If the template's constraints are not satisfied,
9981 then we cannot form a valid type.
9983 Note that the check is deferred until after the hash
9984 lookup. This prevents redundant checks on previously
9985 instantiated specializations. */
9989 {
9991 {
9992 auto_diagnostic_group d;
9995 }
9997 }
10001 /* If the deduced arguments are invalid, then the binding
10002 failed. */
10006 complain))
10013 /* This occurs when the user has tried to define a tagged type
10014 in a scope that forbids it. We emitted an error during the
10015 parse. We didn't complete the bail out then, so here we
10016 are. */
10021 {
10023 /* If the context of the partially instantiated template is
10024 already non-dependent, then we might as well use it. */
10026 else
10027 {
10030 /* Try completing the enclosing context if it's not already so. */
10033 {
10036 {
10037 /* Completion could have caused us to register the desired
10038 specialization already, so check the table again. */
10042 }
10043 }
10044 }
10045 }
10046 else
10055 /* Create the type. */
10057 {
10058 /* The user referred to a specialization of an alias
10059 template represented by GEN_TMPL.
10061 [temp.alias]/2 says:
10063 When a template-id refers to the specialization of an
10064 alias template, it is equivalent to the associated
10065 type obtained by substitution of its
10066 template-arguments for the template-parameters in the
10067 type-id of the alias template. */
10070 /* Note that the call above (by indirectly calling
10071 register_specialization in tsubst_decl) registers the
10072 TYPE_DECL representing the specialization of the alias
10073 template. So next time someone substitutes ARGLIST for
10074 the template parms into the alias template (GEN_TMPL),
10075 she'll get that TYPE_DECL back. */
10079 }
10081 {
10083 {
10094 }
10095 else
10096 {
10097 /* We don't want to call start_enum for this type, since
10098 the values for the enumeration constants may involve
10099 template parameters. And, no one should be interested
10100 in the enumeration constants for such a type. */
10103 }
10107 }
10109 {
10110 /* Lambda closures are regenerated in tsubst_lambda_expr, not
10111 instantiated here. */
10119 /* A local class. Make sure the decl gets registered properly. */
10126 /* This instantiation is another name for the primary
10127 template type. Set the TYPE_CANONICAL field
10128 appropriately. */
10132 }
10133 else
10136 /* If we called start_enum or pushtag above, this information
10137 will already be set up. */
10140 {
10147 }
10150 /* Although GEN_TMPL is the TEMPLATE_DECL, it has the same value
10151 of export flag. We want to propagate this because it might
10152 be a friend declaration that pushes a new hidden binding. */
10156 {
10162 {
10165 }
10166 }
10170 {
10174 {
10175 tree attributes
10183 }
10184 }
10186 /* Let's consider the explicit specialization of a member
10187 of a class template specialization that is implicitly instantiated,
10188 e.g.:
10189 template<class T>
10190 struct S
10191 {
10192 template<class U> struct M {}; //#0
10193 };
10195 template<>
10196 template<>
10197 struct S<int>::M<char> //#1
10198 {
10199 int i;
10200 };
10201 [temp.expl.spec]/4 says this is valid.
10203 In this case, when we write:
10204 S<int>::M<char> m;
10206 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
10207 the one of #0.
10209 When we encounter #1, we want to store the partial instantiation
10210 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
10212 For all cases other than this "explicit specialization of member of a
10213 class template", we just want to store the most general template into
10214 the CLASSTYPE_TI_TEMPLATE of M.
10216 This case of "explicit specialization of member of a class template"
10217 only happens when:
10218 1/ the enclosing class is an instantiation of, and therefore not
10219 the same as, the context of the most general template, and
10220 2/ we aren't looking at the partial instantiation itself, i.e.
10221 the innermost arguments are not the same as the innermost parms of
10222 the most general template.
10224 So it's only when 1/ and 2/ happens that we want to use the partial
10225 instantiation of the member template in lieu of its most general
10226 template. */
10230 /* the enclosing class must be an instantiation... */
10233 {
10237 tree partial_inst_args =
10244 use_partial_inst_tmpl =
10245 /*...and we must not be looking at the partial instantiation
10246 itself. */
10248 partial_inst_args);
10249 }
10252 /* This case is easy; there are no member templates involved. */
10254 else
10255 {
10256 /* This is a full instantiation of a member template. Find
10257 the partial instantiation of which this is an instance. */
10259 /* Temporarily reduce by one the number of levels in the ARGLIST
10260 so as to avoid comparing the last set of arguments. */
10262 /* We don't use COMPLAIN in the following call because this isn't
10263 the immediate context of deduction. For instance, tf_partial
10264 could be set here as we might be at the beginning of template
10265 argument deduction when any explicitly specified template
10266 arguments are substituted into the function type. tf_partial
10267 could lead into trouble because we wouldn't find the partial
10268 instantiation that might have been created outside tf_partial
10269 context, because the levels of template parameters wouldn't
10270 match, because in a tf_partial context, tsubst doesn't reduce
10271 TEMPLATE_PARM_LEVEL. */
10274 /* FOUND is either a proper class type, or an alias
10275 template specialization. In the later case, it's a
10276 TYPE_DECL, resulting from the substituting of arguments
10277 for parameters in the TYPE_DECL of the alias template
10278 done earlier. So be careful while getting the template
10279 of FOUND. */
10281 ? found
10288 {
10289 /* If this partial instantiation is specialized, we want to
10290 use it for hash table lookup. */
10294 }
10295 }
10297 /* Build template info for the new specialization. */
10307 /* Note this use of the partial instantiation so we can check it
10308 later in maybe_process_partial_specialization. */
10316 /* Now that the type has been registered on the instantiations
10317 list, we set up the enumerators. Because the enumeration
10318 constants may involve the enumeration type itself, we make
10319 sure to register the type first, and then create the
10320 constants. That way, doing tsubst_expr for the enumeration
10321 constants won't result in recursive calls here; we'll find
10322 the instantiation and exit above. */
10326 /* If the type makes use of template parameters, the
10327 code that generates debugging information will crash. */
10330 /* Possibly limit visibility based on template args. */
10337 }
10338 }
10340 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
10342 tree
10344 {
10355 /* The type of the expression is NULL_TREE since the template-id could refer
10356 to an explicit or partial specialization. */
10358 }
10360 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR if it's
10361 not dependent. */
10363 tree
10365 {
10369 /* If the template or arguments are dependent, then we
10370 can't resolve the TEMPLATE_ID_EXPR yet. */
10376 {
10378 {
10379 auto_diagnostic_group d;
10382 }
10384 }
10387 }
10389 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
10390 TARGS template args, and instantiate it if it's not dependent. */
10392 tree
10394 tsubst_flags_t complain)
10395 {
10399 /* We may be called while doing a partial substitution, but the
10400 type of the variable template may be auto, in which case we
10401 will call do_auto_deduction in mark_used (which clears tf_partial)
10402 and the auto must be properly reduced at that time for the
10403 deduction to work. */
10408 }
10410 /* If the set of template parameters PARMS contains a template parameter
10411 at the given LEVEL and INDEX, then return this parameter. Otherwise
10412 return NULL_TREE. */
10414 static tree
10416 {
10425 }
10427 /* Return the TREE_LIST for the template parameter from PARMS that positionally
10428 corresponds to the template parameter PARM, or else return NULL_TREE. */
10430 static tree
10432 {
10436 }
10438 /* As above, but pull out the actual parameter. */
10440 static tree
10442 {
10448 /* As in template_parm_to_arg. */
10451 else
10456 }
10457 \f
10458 struct pair_fn_data
10459 {
10460 tree_fn_t fn;
10461 tree_fn_t any_fn;
10463 /* True when we should also visit template parameters that occur in
10464 non-deduced contexts. */
10467 };
10469 /* Called from for_each_template_parm via walk_tree. */
10471 static tree
10473 {
10480 #define WALK_SUBTREE(NODE) \
10481 do \
10482 { \
10483 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
10484 pfd->include_nondeduced_p, \
10485 pfd->any_fn); \
10486 if (result) goto out; \
10487 } \
10488 while (0)
10498 {
10502 /* Fall through. */
10508 else
10518 /* Since we're not going to walk subtrees, we have to do this
10519 explicitly here. */
10521 /* Fall through. */
10524 /* Check the return type. */
10527 /* Check the parameter types. Since default arguments are not
10528 instantiated until they are needed, the TYPE_ARG_TYPES may
10529 contain expressions that involve template parameters. But,
10530 no-one should be looking at them yet. And, once they're
10531 instantiated, they don't contain template parameters, so
10532 there's no point in looking at them then, either. */
10533 {
10534 tree parm;
10539 /* Since we've already handled the TYPE_ARG_TYPES, we don't
10540 want walk_tree walking into them itself. */
10542 }
10545 {
10549 }
10565 {
10568 }
10591 /* Record template parameters such as `T' inside `TT<T>'. */
10593 /* Fall through. */
10605 /* A template template parameter is encountered. */
10609 /* Already substituted template template parameter */
10614 /* A template-id in a TYPENAME_TYPE might be a deduced context after
10615 partial instantiation. */
10622 /* If there's no type, then this thing must be some expression
10623 involving template parameters. */
10633 /* These are non-deduced contexts. */
10655 }
10657 #undef WALK_SUBTREE
10659 /* We didn't find any template parameters we liked. */
10660 out:
10662 }
10664 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
10665 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
10666 call FN with the parameter and the DATA.
10667 If FN returns nonzero, the iteration is terminated, and
10668 for_each_template_parm returns 1. Otherwise, the iteration
10669 continues. If FN never returns a nonzero value, the value
10670 returned by for_each_template_parm is 0. If FN is NULL, it is
10671 considered to be the function which always returns 1.
10673 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
10674 parameters that occur in non-deduced contexts. When false, only
10675 visits those template parameters that can be deduced. */
10677 static tree
10681 tree_fn_t any_fn)
10682 {
10684 tree result;
10686 /* Set up. */
10692 /* Walk the tree. (Conceptually, we would like to walk without
10693 duplicates, but for_each_template_parm_r recursively calls
10694 for_each_template_parm, so we would need to reorganize a fair
10695 bit to use walk_tree_without_duplicates, so we keep our own
10696 visited list.) */
10699 else
10702 for_each_template_parm_r,
10706 /* Clean up. */
10708 {
10711 }
10714 }
10716 struct find_template_parameter_info
10717 {
10721 {}
10727 tree ctx_parms;
10734 };
10736 /* Appends the declaration of T to the list in DATA. */
10738 static int
10740 {
10743 /* Template parameters declared within the expression are not part of
10744 the parameter mapping. For example, in this concept:
10746 template<typename T>
10747 concept C = requires { <expr> } -> same_as<int>;
10749 the return specifier same_as<int> declares a new decltype parameter
10750 that must not be part of the parameter mapping. The same is true
10751 for generic lambda parameters, lambda template parameters, etc. */
10759 /* We want the underlying TEMPLATE_TEMPLATE_PARM, not the
10760 BOUND_TEMPLATE_TEMPLATE_PARM itself. */
10763 /* This template parameter might be an argument to a cached dependent
10764 specalization that was formed earlier inside some other template, in
10765 which case the parameter is not among the ones that are in-scope.
10766 Look in CTX_PARMS to find the corresponding in-scope template
10767 parameter, and use it instead. */
10771 /* Arguments like const T yield parameters like const T. This means that
10772 a template-id like X<T, const T> would yield two distinct parameters:
10773 T and const T. Adjust types to their unqualified versions. */
10777 {
10778 /* Append T to PARM_LIST. */
10782 }
10784 /* Verify the parameter we found has a valid index. */
10786 {
10792 }
10795 }
10797 /* Ensure that we recursively examine certain terms that are not normally
10798 visited in for_each_template_parm_r. */
10800 static int
10802 {
10805 #define WALK_SUBTREE(NODE) \
10806 do \
10807 { \
10808 for_each_template_parm (NODE, keep_template_parm, data, \
10809 &ftpi->visited, true, \
10810 any_template_parm_r); \
10811 } \
10812 while (0)
10814 /* A mention of a member alias/typedef is a use of all of its template
10815 arguments, including those from the enclosing class, so we don't use
10816 alias_template_specialization_p here. */
10822 {
10824 /* Type constraints of a placeholder type may contain parameters. */
10831 /* Search through references to variable templates. */
10841 /* If T is a member template that shares template parameters with
10842 ctx_parms, we need to mark all those parameters for mapping.
10843 To that end, it should suffice to just walk the DECL_CONTEXT of
10844 the template (assuming the template is not overly general). */
10849 {
10850 /* Look in the parms and body. */
10854 }
10859 /* The conversion-type-id of a conversion operator may be dependent. */
10870 }
10872 /* Keep walking. */
10874 }
10876 /* Look through T for template parameters. */
10878 tree
10880 {
10883 any_template_parm_r);
10884 }
10886 /* As above, but also recursively look into the default arguments of template
10887 parameters we found. Used for alias CTAD. */
10889 tree
10891 {
10894 /* Since newly found parms are added to the end of the list, we
10895 can just walk it until we reach the end. */
10897 {
10902 }
10904 }
10906 /* True if PARM was found by a previous call to find_in. PARM can be a
10907 TREE_LIST, a DECL_TEMPLATE_PARM_P, or a TEMPLATE_PARM_P. */
10909 bool
10911 {
10916 else
10920 }
10922 /* Returns a list of unique template parameters found within T, where CTX_PARMS
10923 are the template parameters in scope. */
10925 tree
10927 {
10934 }
10936 /* Returns true if T depends on any template parameter. */
10938 bool
10940 {
10944 /* Namespaces can't depend on any template parameters. */
10960 else
10962 }
10964 /* Returns true if T depends on any template parameter with level LEVEL. */
10966 bool
10968 {
10971 }
10973 /* Returns true if the signature of DECL depends on any template parameter from
10974 its enclosing class. */
10976 static bool
10978 {
10982 else
10991 {
10994 {
10999 template_parm_outer_level,
11009 }
11010 }
11014 }
11016 /* Returns true if the constraints of DECL depend on any template parameters
11017 from its enclosing scope. */
11019 bool
11021 {
11032 }
11034 /* Returns TRUE iff INST is an instantiation we don't need to do in an
11035 ill-formed translation unit, i.e. a variable or function that isn't
11036 usable in a constant expression. */
11040 {
11046 }
11048 /* Returns TRUE iff we should refuse to instantiate DECL because it's
11049 neglectable and instantiated from within an erroneous instantiation. */
11051 static bool
11053 {
11059 /* Avoid instantiating members of an ill-formed class. */
11060 bool refuse
11065 {
11070 }
11073 {
11074 /* Don't warn about it not being defined. */
11076 tree clone;
11079 }
11081 }
11089 /* We're starting to instantiate D; record the template instantiation context
11090 at LOC for diagnostics and to restore it later. */
11092 bool
11094 {
11098 {
11099 /* Tell error.cc not to try to instantiate any templates. */
11102 "template instantiation depth exceeds maximum of %d"
11104 max_tinst_depth);
11106 }
11108 /* If the current instantiation caused problems, don't let it instantiate
11109 anything else. Do allow deduction substitution and decls usable in
11110 constant expressions. */
11112 {
11113 /* Avoid no_linkage_errors and unused function (and all other)
11114 warnings for this decl. */
11117 }
11119 /* When not -quiet, dump template instantiations other than functions, since
11120 announce_function will take care of those. */
11142 }
11144 /* We're starting substitution of TMPL<ARGS>; record the template
11145 substitution context for diagnostics and to restore it later. */
11147 bool
11149 {
11151 }
11153 /* We're starting to instantiate D; record INPUT_LOCATION and the
11154 template instantiation context for diagnostics and to restore it
11155 later. */
11157 bool
11159 {
11161 }
11163 /* Likewise, but record LOC as the program location. */
11165 bool
11167 {
11170 }
11172 /* We're done instantiating this template; return to the instantiation
11173 context. */
11175 void
11177 {
11178 /* Restore the filename and line number stashed away when we started
11179 this instantiation. */
11183 }
11185 /* We're instantiating a deferred template; restore the template
11186 instantiation context in which the instantiation was requested, which
11187 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
11189 static tree
11191 {
11203 }
11205 /* Returns the TINST_LEVEL which gives the original instantiation
11206 context. */
11210 {
11216 }
11218 /* True iff T is a friend function declaration that is not itself a template
11219 and is not defined in a class template. */
11221 bool
11223 {
11226 {
11230 /* DECL_FRIEND_CONTEXT is set for a friend defined in class. */
11233 /* Non-templated friends in a class template are still represented with a
11234 TEMPLATE_DECL; check that its primary template is the befriending
11235 class. Note that DECL_PRIMARY_TEMPLATE is null for
11236 template <class T> friend A<T>::f(); */
11240 }
11241 else
11243 }
11245 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
11246 vector of template arguments, as for tsubst.
11248 Returns an appropriate tsubst'd friend declaration. */
11250 static tree
11252 {
11253 tree new_friend;
11258 /* This was a friend declared with an explicit template
11259 argument list, e.g.:
11261 friend void f<>(T);
11263 to indicate that f was a template instantiation, not a new
11264 function declaration. Now, we have to figure out what
11265 instantiation of what template. */
11266 {
11268 tree new_args;
11269 tree tmpl;
11272 /* Friend functions are looked up in the containing namespace scope.
11273 We must enter that scope, to avoid finding member functions of the
11274 current class with same name. */
11288 tsk_none);
11290 }
11296 /* The NEW_FRIEND will look like an instantiation, to the
11297 compiler, but is not an instantiation from the point of view of
11298 the language. For example, we might have had:
11300 template <class T> struct S {
11301 template <class U> friend void f(T, U);
11302 };
11304 Then, in S<int>, template <class U> void f(int, U) is not an
11305 instantiation of anything. */
11309 {
11315 /* Substitute TEMPLATE_PARMS_CONSTRAINTS so that parameter levels will
11316 match in decls_match. */
11321 {
11323 /* As well as each TEMPLATE_PARM_CONSTRAINTS. */
11325 tf_warning_or_error);
11326 }
11327 }
11329 /* The mangled name for the NEW_FRIEND is incorrect. The function
11330 is not a template instantiation and should not be mangled like
11331 one. Therefore, we forget the mangling here; we'll recompute it
11332 later if we need it. */
11334 {
11337 }
11340 {
11341 tree old_decl;
11342 tree ns;
11344 /* We must save some information from NEW_FRIEND before calling
11345 duplicate decls since that function will free NEW_FRIEND if
11346 possible. */
11350 (new_friend_template_info
11357 {
11358 /* This declaration is a `primary' template. */
11363 }
11365 /* Only define a constrained hidden friend when satisfied. */
11368 /* Inside pushdecl_namespace_level, we will push into the
11369 current namespace. However, the friend function should go
11370 into the namespace of the template. */
11380 {
11381 /* This new friend declaration matched an existing
11382 declaration. For example, given:
11384 template <class T> void f(T);
11385 template <class U> class C {
11386 template <class T> friend void f(T) {}
11387 };
11389 the friend declaration actually provides the definition
11390 of `f', once C has been instantiated for some type. So,
11391 old_decl will be the out-of-class template declaration,
11392 while new_friend is the in-class definition.
11394 But, if `f' was called before this point, the
11395 instantiation of `f' will have DECL_TI_ARGS corresponding
11396 to `T' but not to `U', references to which might appear
11397 in the definition of `f'. Previously, the most general
11398 template for an instantiation of `f' was the out-of-class
11399 version; now it is the in-class version. Therefore, we
11400 run through all specialization of `f', adding to their
11401 DECL_TI_ARGS appropriately. In particular, they need a
11402 new set of outer arguments, corresponding to the
11403 arguments for this class instantiation.
11405 The same situation can arise with something like this:
11407 friend void f(int);
11408 template <class T> class C {
11409 friend void f(T) {}
11410 };
11412 when `C<int>' is instantiated. Now, `f(int)' is defined
11413 in the class. */
11416 /* On the other hand, if the in-class declaration does
11417 *not* provide a definition, then we don't want to alter
11418 existing definitions. We can just leave everything
11419 alone. */
11420 ;
11421 else
11422 {
11426 /* Overwrite whatever template info was there before, if
11427 any, with the new template information pertaining to
11428 the declaration. */
11432 {
11433 /* We should have called reregister_specialization in
11434 duplicate_decls. */
11439 /* Instantiate it if the global has already been used. */
11443 }
11444 else
11445 {
11446 tree t;
11448 /* Indicate that the old function template is a partial
11449 instantiation. */
11457 /* Reassign any specializations already in the hash table
11458 to the new more general template, and add the
11459 additional template args. */
11463 {
11465 spec_entry elt;
11477 register_specialization
11480 }
11482 }
11483 }
11485 /* The information from NEW_FRIEND has been merged into OLD_DECL
11486 by duplicate_decls. */
11488 }
11490 /* We've just introduced a namespace-scope function in the purview
11491 without necessarily having opened the enclosing namespace, so
11492 make sure the namespace is in the purview now too. */
11497 }
11498 else
11499 {
11503 /* In the code
11504 template <class T> class C {
11505 template <class U> friend void C1<U>::f (); // case 1
11506 friend void C2<T>::f (); // case 2
11507 };
11508 we only need to make sure CONTEXT is a complete type for
11509 case 2. To distinguish between the two cases, we note that
11510 CONTEXT of case 1 remains dependent type after tsubst while
11511 this isn't true for case 2. */
11521 {
11523 /* do_friend adds the TEMPLATE_DECL for any member friend
11524 template even if it isn't a member template, i.e.
11525 template <class T> friend A<T>::f();
11526 Look through it in that case. */
11530 /* Check to see that the declaration is really present, and,
11531 possibly obtain an improved declaration. */
11536 }
11537 }
11540 }
11542 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
11543 template arguments, as for tsubst.
11545 Returns an appropriate tsubst'd friend type or error_mark_node on
11546 failure. */
11548 static tree
11550 {
11551 tree tmpl;
11554 {
11557 }
11562 else
11563 {
11566 }
11572 {
11573 /* The friend template has already been declared. Just
11574 check to see that the declarations match, and install any new
11575 default parameters. We must tsubst the default parameters,
11576 of course. We only need the innermost template parameters
11577 because that is all that redeclare_class_template will look
11578 at. */
11581 {
11585 tf_warning_or_error);
11595 }
11596 }
11597 else
11598 {
11599 /* The friend template has not already been declared. In this
11600 case, the instantiation of the template class will cause the
11601 injection of this template into the namespace scope. */
11605 {
11606 /* The new TMPL is not an instantiation of anything, so we
11607 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
11608 for the new type because that is supposed to be the
11609 corresponding template decl, i.e., TMPL. */
11616 /* Substitute into and set the constraints on the new declaration. */
11618 {
11626 }
11628 /* Inject this template into the enclosing namspace scope. */
11630 }
11631 }
11635 else
11639 }
11641 /* Returns zero if TYPE cannot be completed later due to circularity.
11642 Otherwise returns one. */
11644 static int
11646 {
11656 else
11658 }
11663 /* Instantiate the contract statement. */
11665 static tree
11667 tree in_decl)
11668 {
11674 /* Rebuild the result variable. */
11676 {
11684 /* Make sure the postcondition is valid. */
11690 /* Make the variable available for lookup. */
11692 }
11694 /* Instantiate the condition. If the return type is undeduced, process
11695 the expression as if inside a template to avoid spurious type errors. */
11705 /* And the comment. */
11710 }
11712 /* Update T by instantiating its contract attribute. */
11714 static void
11717 {
11718 /* For non-specializations, adjust the current declaration to the most general
11719 version of in_decl. Because we defer the instantiation of contracts as long
11720 as possible, they are still written in terms of the parameters (and return
11721 type) of the most general template. */
11728 /* Get the contract to be instantiated. */
11731 /* Use the complete set of template arguments for instantiation. The
11732 contract may not have been instantiated and still refer to outer levels
11733 of template parameters. */
11736 /* For member functions, make this available for semantic analysis. */
11740 {
11744 }
11751 /* Rebuild the attribute. */
11753 }
11755 /* Rebuild the attribute list for DECL, substituting into contracts
11756 as needed. */
11758 void
11760 {
11763 {
11766 }
11768 }
11770 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
11771 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
11773 static tree
11776 {
11779 /* Note that contract attributes are never substituted from this function.
11780 Their instantiation is triggered by regenerate_from_template_decl when
11781 we instantiate the body of the function. */
11789 {
11796 clauses
11800 else
11802 }
11806 {
11817 {
11821 {
11823 {
11831 }
11832 else
11833 {
11837 {
11838 bool allow_string
11850 {
11851 location_t loc
11853 match_loc);
11859 "integer expression or string "
11861 else
11865 }
11868 {
11869 location_t loc
11871 match_loc);
11875 }
11877 }
11878 }
11879 }
11880 }
11882 }
11883 /* If the first attribute argument is an identifier, don't
11884 pass it through tsubst. Attributes like mode, format,
11885 cleanup and several target specific attributes expect it
11886 unmodified. */
11888 {
11889 tree chain
11893 }
11895 {
11896 /* An attribute pack expansion. */
11905 {
11909 }
11911 }
11912 else
11920 }
11922 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
11923 unchanged or a new TREE_LIST chain. */
11925 static tree
11928 {
11933 {
11937 }
11941 {
11944 {
11947 {
11953 }
11954 }
11956 }
11959 }
11961 /* Apply any attributes which had to be deferred until instantiation
11962 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
11963 ARGS, COMPLAIN, IN_DECL are as tsubst. Returns true normally,
11964 false on error. */
11966 static bool
11969 {
11970 tree t;
11977 {
11981 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
11982 to our attributes parameter. */
11984 }
11985 else
11986 {
11988 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
11989 lookup_template_class_1, and should be preserved. */
11993 }
11995 /* save_template_attributes puts the dependent attributes at the beginning of
11996 the list; find the non-dependent ones. */
12002 /* Apply any non-dependent attributes. */
12008 /* And then any dependent ones. */
12012 {
12017 {
12020 }
12023 }
12025 /* cplus_decl_attributes can add some attributes implicitly. For templates,
12026 those attributes should have been added already when those templates were
12027 parsed, and shouldn't be added based on from which context they are
12028 first time instantiated. */
12031 optimization_default_node);
12034 NULL);
12040 }
12042 /* The template TMPL is being instantiated with the template arguments TARGS.
12043 Perform the access checks that we deferred when parsing the template. */
12045 static void
12047 {
12057 {
12065 /* Make access check error messages point to the location
12066 of the use of the typedef. */
12070 }
12071 }
12073 tree
12075 {
12079 tree typedecl;
12080 tree pbinfo;
12081 tree base_list;
12083 tree fn_context;
12093 /* Figure out which template is being instantiated. */
12097 /* Mark the type as in the process of being defined. */
12100 /* We may be in the middle of deferred access check. Disable
12101 it now. */
12104 /* Determine what specialization of the original template to
12105 instantiate. */
12110 {
12111 /* This TYPE is actually an instantiation of a partial
12112 specialization. We replace the innermost set of ARGS with
12113 the arguments appropriate for substitution. For example,
12114 given:
12116 template <class T> struct S {};
12117 template <class T> struct S<T*> {};
12119 and supposing that we are instantiating S<int*>, ARGS will
12120 presently be {int*} -- but we need {int}. */
12123 }
12124 else
12125 {
12128 }
12130 /* If the template we're instantiating is incomplete, then clearly
12131 there's nothing we can do. */
12133 {
12134 /* We can try again later. */
12137 }
12139 /* If we've recursively instantiated too many templates, stop. */
12147 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
12152 else
12153 {
12156 }
12160 /* Use #pragma pack from the template context. */
12166 /* Set the input location to the most specialized template definition.
12167 This is needed if tsubsting causes an error. */
12181 {
12184 /* Adjust visibility for template arguments. */
12186 }
12192 /* We should never instantiate a nested class before its enclosing
12193 class; we need to look up the nested class by name before we can
12194 instantiate it, and that lookup should instantiate the enclosing
12195 class. */
12200 /* Defer access checking while we substitute into the types named in
12201 the base-clause. */
12204 {
12205 tree pbase_binfo;
12208 /* Substitute into each of the bases to determine the actual
12209 basetypes. */
12211 {
12212 tree base;
12218 {
12219 expanded_bases =
12226 }
12229 {
12231 /* Extract the already-expanded base class. */
12233 else
12234 /* Substitute to figure out the base class. */
12236 NULL_TREE);
12244 }
12245 }
12247 /* The list is now in reverse order; correct that. */
12249 }
12250 /* Now call xref_basetypes to set up all the base-class
12251 information. */
12259 /* Now that our base classes are set up, enter the scope of the
12260 class, so that name lookups into base classes, etc. will work
12261 correctly. This is precisely analogous to what we do in
12262 begin_class_definition when defining an ordinary non-template
12263 class, except we also need to push the enclosing classes. */
12266 /* Now check accessibility of the types named in its base-clause,
12267 relative to the scope of the class. */
12270 /* A vector to hold members marked with attribute used. */
12273 /* Now members are processed in the order of declaration. */
12276 {
12280 {
12282 {
12284 /* A closure type for a lambda in an NSDMI or default argument.
12285 Ignore it; it will be regenerated when needed. */
12288 /* If the member is a class template, we've
12289 already substituted its type. */
12299 {
12302 /* Now, install the tag. We don't use pushtag
12303 because that does too much work -- creating an
12304 implicit typedef, which we've already done. */
12309 }
12310 }
12312 {
12313 tree r;
12323 /* Instantiate members marked with attribute used. */
12329 }
12332 /* A closure type for a lambda in an NSDMI or default argument.
12334 else
12335 {
12336 /* Build new TYPE_FIELDS. */
12340 {
12341 tree r;
12346 /* The file and line for this declaration, to
12347 assist in error message reporting. Since we
12348 called push_tinst_level above, we don't need to
12349 restore these. */
12359 {
12360 /* A capture pack became multiple fields. */
12363 }
12366 {
12370 {
12371 /* In [temp.inst]:
12373 [t]he initialization (and any associated
12374 side-effects) of a static data member does
12375 not occur unless the static data member is
12376 itself used in a way that requires the
12377 definition of the static data member to
12378 exist.
12380 Therefore, we do not substitute into the
12381 initialized for the static data member here. */
12382 finish_static_data_member_decl
12388 /* Instantiate members marked with attribute used. */
12391 }
12393 {
12394 /* Determine whether R has a valid type and can be
12395 completed later. If R is invalid, then its type
12396 is replaced by error_mark_node. */
12402 {
12403 /* If R's type couldn't be completed and
12404 it isn't a flexible array member (whose
12405 type is incomplete by definition) give
12406 an error. */
12409 }
12414 {
12417 }
12421 }
12423 /* If it is a TYPE_DECL for a class-scoped
12424 ENUMERAL_TYPE, such a thing will already have
12425 been added to the field list by tsubst_enum
12426 in finish_member_declaration case above. */
12430 {
12433 }
12434 }
12435 }
12436 }
12437 }
12438 else
12439 {
12442 {
12443 /* Build new CLASSTYPE_FRIEND_CLASSES. */
12447 {
12448 /* template <class T> friend class C; */
12450 }
12452 {
12453 /* template <class T> friend class C::D; */
12458 }
12461 {
12462 /* This could be either
12464 friend class T::C;
12466 when dependent_type_p is false or
12468 template <class U> friend class T::C;
12470 otherwise. */
12471 /* Bump processing_template_decl in case this is something like
12472 template <class T> friend struct A<T>::B. */
12477 }
12479 /* friend class C<T>; */
12483 /* Otherwise it's
12485 friend class C;
12487 where C is already declared or
12489 friend class C<int>;
12491 We don't have to do anything in these cases. */
12495 }
12496 else
12497 {
12498 /* Build new DECL_FRIENDLIST. */
12499 tree r;
12501 /* The file and line for this declaration, to
12502 assist in error message reporting. Since we
12503 called push_tinst_level above, we don't need to
12504 restore these. */
12508 {
12511 }
12516 {
12519 }
12520 }
12521 }
12522 }
12525 {
12526 /* Restore these before substituting into the lambda capture
12527 initializers. */
12530 }
12532 /* Set the file and line number information to whatever is given for
12533 the class itself. This puts error messages involving generated
12534 implicit functions at a predictable point, and the same point
12535 that would be used for non-template classes. */
12542 /* Remember if instantiating this class ran into errors, so we can avoid
12543 instantiating member functions in limit_bad_template_recursion. We set
12544 this flag even if the problem was in another instantiation triggered by
12545 this one, as that will likely also cause trouble for member functions. */
12549 /* We don't instantiate default arguments for member functions. 14.7.1:
12551 The implicit instantiation of a class template specialization causes
12552 the implicit instantiation of the declarations, but not of the
12553 definitions or default arguments, of the class member functions,
12554 member classes, static data members and member templates.... */
12559 /* Now that we've gone through all the members, instantiate those
12560 marked with attribute used. We must do this in the context of
12561 the class -- not the context we pushed from, as that might be
12562 inside a template and change the behaviour of mark_used. */
12572 /* The vtable for a template class can be emitted in any translation
12573 unit in which the class is instantiated. When there is no key
12574 method, however, finish_struct_1 will already have added TYPE to
12575 the keyed_classes. */
12580 }
12582 tree
12584 {
12585 tree r;
12591 else
12592 {
12598 }
12601 }
12603 /* Given a function parameter pack TMPL_PARM and some function parameters
12604 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
12605 and set *SPEC_P to point at the next point in the list. */
12607 tree
12609 {
12610 /* Collect all of the extra "packed" parameters into an
12611 argument pack. */
12612 tree argpack;
12623 {
12624 /* The instantiation is still a parameter pack; don't wrap it in a
12625 NONTYPE_ARGUMENT_PACK. */
12628 }
12629 else
12630 {
12631 /* Fill in PARMVEC with all of the parameters. */
12635 {
12641 }
12643 /* Build the argument packs. */
12645 }
12649 }
12651 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
12652 NONTYPE_ARGUMENT_PACK. */
12654 static tree
12656 {
12658 }
12660 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
12661 pack expansion with no extra args, 2 if it has extra args, or 0
12662 if it is not a pack expansion. */
12664 static int
12666 {
12668 /* We're being called before this happens in tsubst_pack_expansion. */
12675 /* A decl pack is itself an expansion. */
12682 }
12685 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
12687 static tree
12689 {
12696 }
12698 /* This is a subroutine of tsubst_pack_expansion.
12700 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
12701 mechanism to store the (non complete list of) arguments of the
12702 substitution and return a non substituted pack expansion, in order
12703 to wait for when we have enough arguments to really perform the
12704 substitution. */
12706 static bool
12708 tree parm_packs,
12711 {
12716 /* If one pack has an expansion and another pack has a normal
12717 argument or if one pack has an empty argument and an another
12718 one hasn't then tsubst_pack_expansion cannot perform the
12719 substitution and need to fall back on the
12720 PACK_EXPANSION_EXTRA mechanism. */
12724 {
12725 /* If all the actual packs are pack expansions, we can still
12726 subsitute directly. */
12728 {
12738 }
12740 }
12743 {
12747 parm_pack;
12749 {
12754 /* We can't substitute a pack expansion with extra args into
12755 our pattern. */
12759 else
12761 }
12764 {
12767 }
12768 }
12770 }
12772 /* [temp.variadic]/6 says that:
12774 The instantiation of a pack expansion [...]
12775 produces a list E1,E2, ..., En, where N is the number of elements
12776 in the pack expansion parameters.
12778 This subroutine of tsubst_pack_expansion produces one of these Ei.
12780 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
12781 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
12782 PATTERN, and each TREE_VALUE is its corresponding argument pack.
12783 INDEX is the index 'i' of the element Ei to produce. ARGS,
12784 COMPLAIN, and IN_DECL are the same parameters as for the
12785 tsubst_pack_expansion function.
12787 The function returns the resulting Ei upon successful completion,
12788 or error_mark_node.
12790 Note that this function possibly modifies the ARGS parameter, so
12791 it's the responsibility of the caller to restore it. */
12793 static tree
12795 tree parm_packs,
12797 tree args /* This parm gets
12799 tsubst_flags_t complain,
12800 tree in_decl)
12801 {
12802 tree t;
12805 /* For each parameter pack, change the substitution of the parameter
12806 pack to the ith argument in its argument pack, then expand the
12807 pattern. */
12809 {
12814 ith_elem_is_expansion |=
12817 /* Select the Ith argument from the pack. */
12821 {
12823 {
12828 }
12829 else
12831 }
12832 else
12833 {
12838 {
12840 /* Update the corresponding argument. */
12842 }
12843 else
12844 /* Re-use the ARGUMENT_PACK_SELECT. */
12846 }
12848 }
12850 /* Substitute into the PATTERN with the (possibly altered)
12851 arguments. */
12853 /* Expanding a fixed parameter pack from
12854 coerce_template_parameter_pack. */
12860 else
12861 {
12864 /* When expanding the fake auto... pack expansion from add_capture, we
12865 need to mark that the expansion is no longer a pack. */
12867 }
12869 /* If the Ith argument pack element is a pack expansion, then
12870 the Ith element resulting from the substituting is going to
12871 be a pack expansion as well. */
12876 }
12878 /* When the unexpanded parameter pack in a fold expression expands to an empty
12879 sequence, the value of the expression is as follows; the program is
12880 ill-formed if the operator is not listed in this table.
12882 && true
12883 || false
12884 , void() */
12886 tree
12888 {
12892 {
12901 }
12907 }
12909 /* Given a fold-expression T and a current LEFT and RIGHT operand,
12910 form an expression that combines the two terms using the
12911 operator of T. */
12913 static tree
12915 {
12920 // Handle compound assignment operators.
12927 {
12936 complain);
12937 }
12938 }
12940 /* Substitute ARGS into the pack of a fold expression T. */
12944 {
12946 }
12948 /* Substitute ARGS into the pack of a fold expression T. */
12952 {
12954 }
12956 /* Expand a PACK of arguments into a grouped as left fold.
12957 Given a pack containing elements A0, A1, ..., An and an
12958 operator @, this builds the expression:
12960 ((A0 @ A1) @ A2) ... @ An
12962 Note that PACK must not be empty.
12964 The operator is defined by the original fold expression T. */
12966 static tree
12968 {
12971 {
12974 }
12976 }
12978 /* Substitute into a unary left fold expression. */
12980 static tree
12982 tree in_decl)
12983 {
12988 {
12992 }
12995 else
12997 }
12999 /* Substitute into a binary left fold expression.
13001 Do ths by building a single (non-empty) vector of argumnts and
13002 building the expression from those elements. */
13004 static tree
13006 tree in_decl)
13007 {
13016 {
13021 }
13029 }
13031 /* Expand a PACK of arguments into a grouped as right fold.
13032 Given a pack containing elementns A0, A1, ..., and an
13033 operator @, this builds the expression:
13035 A0@ ... (An-2 @ (An-1 @ An))
13037 Note that PACK must not be empty.
13039 The operator is defined by the original fold expression T. */
13041 tree
13043 {
13044 // Build the expression.
13048 {
13051 }
13053 }
13055 /* Substitute into a unary right fold expression. */
13057 static tree
13059 tree in_decl)
13060 {
13065 {
13069 }
13072 else
13074 }
13076 /* Substitute into a binary right fold expression.
13078 Do ths by building a single (non-empty) vector of arguments and
13079 building the expression from those elements. */
13081 static tree
13083 tree in_decl)
13084 {
13093 {
13098 }
13107 }
13109 /* Walk through the pattern of a pack expansion, adding everything in
13110 local_specializations to a list. */
13112 class el_data
13113 {
13115 /* Set of variables declared within the pattern. */
13117 /* Set of AST nodes that have been visited by the traversal. */
13119 /* List of local_specializations used within the pattern. */
13120 tree extra;
13121 tsubst_flags_t complain;
13122 /* True iff we don't want to walk into unevaluated contexts. */
13124 /* The unevaluated contexts that we avoided walking. */
13129 };
13130 static tree
13132 {
13139 {
13143 }
13146 /* Remember local typedefs (85214). */
13150 {
13156 {
13159 decl2
13165 {
13168 }
13169 }
13170 }
13172 {
13173 /* Since we defer implicit capture, look in the parms and body. */
13179 }
13181 {
13183 /* Don't mess with variables declared within the pattern. */
13186 {
13187 /* Maybe pull out the PARM_DECL for a partial instantiation. */
13190 {
13196 }
13198 {
13199 /* Handle lambda capture here, since we aren't doing any
13200 substitution now, and so tsubst_copy won't call
13201 process_outer_var_ref. */
13205 {
13211 {
13212 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
13213 proxies. */
13215 {
13220 }
13222 }
13223 }
13224 }
13225 }
13229 }
13231 }
13232 static tree
13234 {
13236 /* Walk the pattern twice, ignoring unevaluated operands the first time
13237 around, so that if a local specialization appears in both an evaluated
13238 and unevaluated context we prefer to process it in the evaluated context
13239 (since e.g. process_outer_var_ref is a no-op inside an unevaluated
13240 context). */
13243 /* Now walk the unevaluated contexts we skipped the first time around. */
13246 {
13249 }
13251 }
13253 /* Extract any uses of local_specializations from PATTERN and add them to ARGS
13254 for use in PACK_EXPANSION_EXTRA_ARGS. */
13256 tree
13258 {
13259 /* Make a copy of the extra arguments so that they won't get changed
13260 out from under us. */
13266 }
13268 /* Apply any local specializations from PACK_EXPANSION_EXTRA_ARGS and add the
13269 normal template args to ARGS. */
13271 tree
13273 {
13275 {
13277 {
13278 /* The partial instantiation involved local declarations collected in
13279 extract_local_specs; map from the general template to our local
13280 context. */
13286 /* else inst is already a full instantiation of the pack. */
13288 }
13291 }
13293 {
13294 /* This can happen after dependent substitution into a
13295 requires-expr or a lambda that uses constexpr if. */
13298 }
13299 else
13302 }
13304 /* Substitute ARGS into T, which is an pack expansion
13305 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
13306 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
13307 (if only a partial substitution could be performed) or
13308 ERROR_MARK_NODE if there was an error. */
13309 tree
13311 tree in_decl)
13312 {
13313 tree pattern;
13317 tree result;
13324 /* Add in any args remembered from an earlier partial instantiation. */
13329 /* Determine the argument packs that will instantiate the parameter
13330 packs used in the expansion expression. While we're at it,
13331 compute the number of arguments to be expanded and make sure it
13332 is consistent. */
13335 {
13342 {
13347 in_decl),
13348 complain);
13349 else
13352 complain);
13353 }
13355 {
13357 {
13360 parm_pack);
13362 }
13365 }
13367 {
13368 /* We know we have correct local_specializations if this
13369 expansion is at function scope, or if we're dealing with a
13370 local parameter in a requires expression; for the latter,
13371 tsubst_requires_expr set it up appropriately. */
13374 else
13375 /* We can't rely on local_specializations for a parameter
13376 name used later in a function declaration (such as in a
13377 late-specified return type). Even if it exists, it might
13378 have the wrong value for a recursive call. */
13382 {
13383 /* This parameter pack was used in an unevaluated context. Just
13384 make a dummy decl, since it's only used for its type. */
13389 /* Partial instantiation of the parm_pack, we can't build
13390 up an argument pack yet. */
13392 else
13394 }
13396 /* This argument pack isn't fully instantiated yet. */
13398 }
13400 {
13404 }
13405 else
13406 {
13415 }
13422 /* This can only happen if we forget to expand an argument
13423 pack somewhere else. Just return an error, silently. */
13424 {
13428 }
13431 {
13435 /* Don't bother trying to do a partial substitution with
13436 incomplete packs; we'll try again after deduction. */
13443 {
13448 pattern);
13449 else
13451 pattern);
13453 }
13455 /* Keep track of the parameter packs and their corresponding
13456 argument packs. */
13459 }
13460 else
13461 {
13462 /* We can't substitute for this parameter pack. We use a flag as
13463 well as the missing_level counter because function parameter
13464 packs don't have a level. */
13467 }
13468 }
13470 /* If the expansion is just T..., return the matching argument pack, unless
13471 we need to call convert_from_reference on all the elements. This is an
13472 important optimization; see c++/68422. */
13475 {
13478 /* If the argument pack is a single pack expansion, pull it out. */
13483 /* Types need no adjustment, nor does sizeof..., and if we still have
13484 some pack expansion args we won't do anything yet. */
13489 /* Also optimize expression pack expansions if we can tell that the
13490 elements won't have reference type. */
13496 /* Otherwise use the normal path so we get convert_from_reference. */
13497 }
13499 /* We cannot expand this expansion expression, because we don't have
13500 all of the argument packs we need. */
13502 {
13503 /* We got some full packs, but we can't substitute them in until we
13504 have values for all the packs. So remember these until then. */
13510 }
13512 /* If NEED_LOCAL_SPECIALIZATIONS then we're in a late-specified return
13513 type, so create our own local specializations map; the current map is
13514 either NULL or (in the case of recursive unification) might have
13515 bindings that we don't want to use or alter. */
13520 {
13521 /* There were no real arguments, we're just replacing a parameter
13522 pack with another version of itself. Substitute into the
13523 pattern and return a PACK_EXPANSION_*. The caller will need to
13524 deal with that. */
13527 else
13533 {
13534 /* This is a fake auto... pack expansion created in add_capture with
13535 _PACKS that don't appear in the pattern. Copy one over. */
13542 }
13544 }
13548 /* For each argument in each argument pack, substitute into the
13549 pattern. */
13553 {
13555 i,
13557 in_decl);
13560 {
13563 }
13564 }
13566 /* Update ARGS to restore the substitution from parameter packs to
13567 their argument packs. */
13569 {
13576 else
13577 {
13585 /* Update the corresponding argument. */
13589 else
13591 }
13592 }
13594 /* If the dependent pack arguments were such that we end up with only a
13595 single pack expansion again, there's no need to keep it in a TREE_VEC. */
13601 }
13603 /* Make an argument pack out of the TREE_VEC VEC. */
13605 static tree
13607 {
13608 tree pack;
13612 else
13613 {
13616 }
13619 }
13621 /* Return an exact copy of template args T that can be modified
13622 independently. */
13624 static tree
13626 {
13634 {
13639 }
13645 }
13647 /* Substitute ARGS into the *_ARGUMENT_PACK orig_arg. */
13649 tree
13651 tree in_decl)
13652 {
13653 /* This flag is used only during deduction, and we don't expect to
13654 substitute such ARGUMENT_PACKs. */
13657 /* Substitute into each of the arguments. */
13666 /* If we're substituting into a generic ARGUMENT_PACK for a variadic
13667 template parameter, we might be able to avoid allocating a new
13668 ARGUMENT_PACK and reuse the corresponding ARGUMENT_PACK from ARGS
13669 if the substituted result is identical to it. */
13671 {
13678 {
13681 }
13682 }
13684 tree new_arg;
13686 {
13689 }
13690 else
13691 {
13694 }
13697 }
13699 /* Substitute ARGS into the vector or list of template arguments T. */
13701 tree
13703 {
13707 /* In "sizeof(X<I>)" we need to evaluate "I". */
13708 cp_evaluated ev;
13714 /* True iff the substituted result is identical to T. */
13718 {
13720 tree new_arg;
13727 {
13728 /* Substitute into an expansion expression. */
13732 /* Add to the expanded length adjustment the number of
13733 expanded arguments. We subtract one from this
13734 measurement, because the argument pack expression
13735 itself is already counted as 1 in
13736 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
13737 the argument pack is empty. */
13739 }
13742 else
13751 }
13758 /* If ARGS and T are both multi-level, the substituted result may be
13759 identical to ARGS. */
13764 /* If T appears to be a vector of generic template arguments, the
13765 substituted result may be identical to the corresponding level
13766 from ARGS. */
13768 {
13773 }
13775 /* If the substituted result is identical to MAYBE_REUSE, return
13776 it and avoid allocating a new TREE_VEC, as an optimization. */
13782 /* If T consists of only a pack expansion for which substitution yielded
13783 a TREE_VEC of the expanded elements, then reuse that TREE_VEC instead
13784 of effectively making a copy. */
13790 /* Make space for the expanded arguments coming from template
13791 argument packs. */
13793 /* T can contain TREE_VECs. That happens if T contains the
13794 arguments for a member template.
13795 In that case each TREE_VEC in T represents a level of template
13796 arguments, and T won't carry any non defaulted argument count.
13797 It will rather be the nested TREE_VECs that will carry one.
13798 In other words, T carries a non defaulted argument count only
13799 if it doesn't contain any nested TREE_VEC. */
13801 {
13805 }
13809 {
13814 {
13815 /* Now expand the template argument pack "in place". */
13818 }
13819 else
13820 {
13822 out++;
13823 }
13824 }
13828 }
13830 /* Substitute ARGS into one level PARMS of template parameters. */
13832 static tree
13834 {
13841 {
13849 }
13852 }
13854 /* Return the result of substituting ARGS into the template parameters
13855 given by PARMS. If there are m levels of ARGS and m + n levels of
13856 PARMS, then the result will contain n levels of PARMS. For
13857 example, if PARMS is `template <class T> template <class U>
13858 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
13859 result will be `template <int*, double, class V>'. */
13861 static tree
13863 {
13867 /* When substituting into a template, we must set
13868 PROCESSING_TEMPLATE_DECL as the template parameters may be
13869 dependent if they are based on one-another, and the dependency
13870 predicates are short-circuit outside of templates. */
13877 {
13886 }
13891 }
13893 /* Return the result of substituting ARGS into one template parameter
13894 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
13895 parameter and which TREE_PURPOSE is the default argument of the
13896 template parameter. */
13898 static tree
13900 {
13923 }
13925 /* Substitute in-place the TEMPLATE_PARM_CONSTRAINTS of each template
13926 parameter in PARMS for sake of declaration matching. */
13928 static void
13930 tsubst_flags_t complain)
13931 {
13934 {
13940 }
13942 }
13944 /* Substitute the ARGS into the indicated aggregate (or enumeration)
13945 type T. If T is not an aggregate or enumeration type, it is
13946 handled as if by tsubst. IN_DECL is as for tsubst. If
13947 ENTERING_SCOPE is nonzero, T is the context for a template which
13948 we are presently tsubst'ing. Return the substituted value. */
13950 static tree
13952 tree args,
13953 tsubst_flags_t complain,
13954 tree in_decl,
13956 {
13960 /* Handle typedefs via tsubst so that they get consistently reused. */
13962 {
13967 /* The effect of entering_scope is that for a dependent specialization
13968 A<T>, lookup_template_class prefers to return A's primary template
13969 type instead of the implicit instantiation. So when entering_scope,
13970 we mirror this behavior by inspecting TYPE_CANONICAL appropriately,
13971 taking advantage of the fact that lookup_template_class links the two
13972 types by setting TYPE_CANONICAL of the latter to the former. */
13980 }
13983 {
13991 }
13992 }
13994 /* The part of tsubst_aggr_type that's shared with the RECORD_, UNION_
13995 and ENUMERAL_TYPE cases of tsubst. */
13997 static tree
13999 tree args,
14000 tsubst_flags_t complain,
14001 tree in_decl,
14003 {
14005 {
14008 /* Figure out what arguments are appropriate for the
14009 type we are trying to find. For example, given:
14011 template <class T> struct S;
14012 template <class T, class U> void f(T, U) { S<U> su; }
14014 and supposing that we are instantiating f<int, double>,
14015 then our ARGS will be {int, double}, but, when looking up
14016 S we only want {double}. */
14025 }
14026 else
14027 /* This is not a template type, so there's nothing to do. */
14029 }
14031 /* Map from a FUNCTION_DECL to a vec of default argument instantiations,
14032 indexed in reverse order of the parameters. */
14036 /* Return a reference to the vec* of defarg insts for FN. */
14040 {
14044 tree_vec_map **slot
14047 {
14050 }
14052 }
14054 /* Substitute into the default argument ARG (a default argument for
14055 FN), which has the indicated TYPE. */
14057 tree
14059 tsubst_flags_t complain)
14060 {
14063 /* This can happen in invalid code. */
14067 /* Shortcut {}. */
14082 /* Remember the location of the pointer to the vec rather than the location
14083 of the particular element, in case the vec grows in tsubst_expr. */
14085 /* Index in reverse order to avoid allocating space for initial parameters
14086 that don't have default arguments. */
14093 /* This default argument came from a template. Instantiate the
14094 default argument here, not in tsubst. In the case of
14095 something like:
14097 template <class T>
14098 struct S {
14099 static T t();
14100 void f(T = t());
14101 };
14103 we must be careful to do name lookup in the scope of S<T>,
14104 rather than in the current class. */
14108 /* So in_immediate_context knows this is a default argument. */
14112 /* The default argument expression may cause implicitly defined
14113 member functions to be synthesized, which will result in garbage
14114 collection. We must treat this situation as if we were within
14115 the body of function so as to avoid collecting live data on the
14116 stack. */
14123 /* Make sure the default argument is reasonable. */
14140 }
14142 /* Substitute into all the default arguments for FN. */
14144 static void
14146 {
14147 tree arg;
14148 tree tmpl_args;
14152 /* If this function is not yet instantiated, we certainly don't need
14153 its default arguments. */
14156 /* Don't do this again for clones. */
14162 arg;
14168 complain);
14169 }
14171 /* Hash table mapping a FUNCTION_DECL to its dependent explicit-specifier. */
14174 /* Store a pair to EXPLICIT_SPECIFIER_MAP. */
14176 void
14178 {
14183 }
14185 /* Lookup an element in EXPLICIT_SPECIFIER_MAP. */
14187 tree
14189 {
14191 }
14193 /* Given T, a FUNCTION_TYPE or METHOD_TYPE, construct and return a corresponding
14194 FUNCTION_TYPE or METHOD_TYPE whose return type is RETURN_TYPE, argument types
14195 are ARG_TYPES, and exception specification is RAISES, and otherwise is
14196 identical to T. */
14198 static tree
14201 {
14204 tree new_type;
14206 {
14209 }
14210 else
14211 {
14213 /* Don't pick up extra function qualifiers from the basetype. */
14216 {
14217 /* [temp.deduct]
14219 Type deduction may fail for any of the following
14220 reasons:
14222 -- Attempting to create "pointer to member of T" when T
14223 is not a class type. */
14226 r);
14228 }
14232 }
14238 }
14240 /* Check if the function type of DECL, a FUNCTION_DECL, agrees with the type of
14241 each of its formal parameters. If there is a disagreement then rebuild
14242 DECL's function type according to its formal parameter types, as part of a
14243 resolution for Core issues 1001/1322. */
14245 static void
14247 {
14250 {
14253 {
14257 {
14260 }
14264 }
14265 }
14276 {
14281 }
14283 {
14293 }
14301 }
14303 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
14305 static tree
14308 {
14313 /* Nobody should be tsubst'ing into non-template functions. */
14318 {
14321 }
14323 {
14324 /* If T is not dependent, just return it. */
14329 /* A non-templated friend doesn't get DECL_TEMPLATE_INFO. */
14333 /* Calculate the most general template of which R is a
14334 specialization. */
14337 /* We're substituting a lambda function under tsubst_lambda_expr but not
14338 directly from it; find the matching function we're already inside.
14339 But don't do this if T is a generic lambda with a single level of
14340 template parms, as in that case we're doing a normal instantiation. */
14346 /* Calculate the complete set of arguments used to
14347 specialize R. */
14349 {
14351 (DECL_TEMPLATE_RESULT
14357 /* Check to see if we already have this specialization. */
14359 {
14362 /* The spec for these args might be a partial instantiation of the
14363 template, but here what we want is the FUNCTION_DECL. */
14365 }
14366 }
14367 else
14369 }
14370 else
14371 {
14372 /* This special case arises when we have something like this:
14374 template <class T> struct S {
14375 friend void f<int>(int, double);
14376 };
14378 Here, the DECL_TI_TEMPLATE for the friend declaration
14379 will be an IDENTIFIER_NODE. We are being called from
14380 tsubst_friend_function, and we want only to create a
14381 new decl (R) with appropriate types so that we can call
14382 determine_specialization. */
14383 friend_case:
14386 }
14393 /* If this is a static lambda, remove the 'this' pointer added in
14394 tsubst_lambda_expr now that we know the closure type. */
14408 /* If we hit excessive deduction depth, the type is bogus even if
14409 it isn't error_mark_node, so don't build a decl. */
14413 /* We do NOT check for matching decls pushed separately at this
14414 point, as they may not represent instantiations of this
14415 template, and in any case are considered separate under the
14416 discrete model. */
14420 /* Clear out the mangled name and RTL for the instantiation. */
14423 /* Leave DECL_INITIAL set on deleted instantiations. */
14429 /* Handle explicit(dependent-expr). */
14431 {
14439 else
14440 {
14443 }
14444 }
14446 /* OpenMP UDRs have the only argument a reference to the declared
14447 type. We want to diagnose if the declared type is a reference,
14448 which is invalid, but as references to references are usually
14449 quietly merged, diagnose it here. */
14451 {
14452 tree argtype
14457 "reference type %qT in "
14461 argtype);
14462 }
14465 /* Type-conversion operator. Reconstruct the name, in
14466 case it's the name of one of the template's parameters. */
14476 {
14481 }
14490 /* If this is an instantiation of a function with internal
14491 linkage, we already know what object file linkage will be
14492 assigned to the instantiation. */
14501 /* We'll re-clone as appropriate in instantiate_template. */
14504 /* If we aren't complaining now, return on error before we register
14505 the specialization so that we'll complain eventually. */
14511 /* Associate the constraints directly with the instantiation. We
14512 don't substitute through the constraints; that's only done when
14513 they are checked. */
14526 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
14527 this in the special friend case mentioned above where
14528 GEN_TMPL is NULL. */
14530 {
14536 {
14537 tree new_r
14540 /* We instantiated this while substituting into
14541 the type earlier (template/friend54.C). */
14543 }
14545 /* We're not supposed to instantiate default arguments
14546 until they are called, for a template. But, for a
14547 declaration like:
14549 template <class T> void f ()
14550 { extern void g(int i = T()); }
14552 we should do the substitution when the template is
14553 instantiated. We handle the member function case in
14554 instantiate_class_template since the default arguments
14555 might refer to other members of the class. */
14560 }
14562 {
14565 }
14566 else
14569 /* Copy the list of befriending classes. */
14573 {
14577 }
14580 {
14584 /* If this is an instantiation of a member template, clone it.
14585 If it isn't, that'll be handled by
14586 clone_constructors_and_destructors. */
14589 }
14595 /* Possibly limit visibility based on template args. */
14598 {
14602 }
14614 }
14616 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
14618 static tree
14621 {
14622 /* We can get here when processing a member function template,
14623 member class template, or template template parameter. */
14626 tree spec;
14627 tree tmpl_args;
14628 tree full_args;
14629 tree r;
14633 {
14634 /* Template template parameter is treated here. */
14638 /* If we get a real template back, return it. This can happen in
14639 the context of most_specialized_partial_spec. */
14642 else
14643 /* The new TEMPLATE_DECL was built in
14644 reduce_template_parm_level. */
14647 }
14650 {
14651 /* We might already have an instance of this template.
14652 The ARGS are for the surrounding class type, so the
14653 full args contain the tsubst'd args for the context,
14654 plus the innermost args from the template decl. */
14658 /* Because this is a template, the arguments will still be
14659 dependent, even after substitution. If
14660 PROCESSING_TEMPLATE_DECL is not set, the dependency
14661 predicates will short-circuit. */
14669 /* If this is a default template template argument,
14670 tsubst might not have changed anything. */
14677 {
14679 /* Type partial instantiations are stored as the type by
14680 lookup_template_class_1, not here as the template. */
14683 }
14684 }
14686 /* Make a new template decl. It will be similar to the
14687 original, but will record the current template arguments.
14688 We also create a new function declaration, which is just
14689 like the old one, but points to this new template, rather
14690 than the old one. */
14695 // Build new template info linking to the original template decl.
14697 {
14700 }
14701 else
14704 /* The template parameters for this new template are all the
14705 template parameters for the old template, except the
14706 outermost level of parameters. */
14709 = current_template_parms
14710 = (lambda_tparms
14711 ? lambda_tparms
14713 complain));
14720 else
14721 {
14723 {
14726 }
14730 else
14732 }
14738 {
14739 /* For a partial specialization, we need to keep pointing to
14740 the primary template. */
14742 {
14745 }
14749 }
14751 {
14754 }
14755 else
14756 {
14759 }
14766 {
14767 /* Propagate module information from the decl. */
14770 /* If this is a constrained template, the above tsubst of
14771 inner can find the unconstrained template, which may have
14772 come from an import. This is ok, because we don't
14773 register this instantiation (see below). */
14775 || (TEMPLATE_PARMS_CONSTRAINTS
14777 }
14786 /* Record this non-type partial instantiation. */
14792 }
14794 /* True if FN is the op() for a lambda in an uninstantiated template. */
14796 bool
14798 {
14803 }
14805 /* True if FN is the substitution (via tsubst_lambda_expr) of a function for
14806 which the above is true. */
14808 bool
14810 {
14816 }
14818 /* Return the LAMBDA_EXPR from which T was ultimately regenerated.
14819 If T is not a regenerated LAMBDA_EXPR, return T. */
14821 tree
14823 {
14827 }
14829 /* Return the set of template arguments used to regenerate the lambda T
14830 from its most general lambda. */
14832 tree
14834 {
14840 else
14842 }
14844 /* We're instantiating a variable from template function TCTX. Return the
14845 corresponding current enclosing scope. We can match them up using
14846 DECL_SOURCE_LOCATION because lambdas only ever have one source location, and
14847 the DECL_SOURCE_LOCATION for a function instantiation is updated to match
14848 the template definition in regenerate_decl_from_template. */
14850 static tree
14852 {
14855 /* We shouldn't ever need to do this for other artificial functions. */
14862 }
14864 /* Substitute the ARGS into the T, which is a _DECL. Return the
14865 result of the substitution. Issue error and warning messages under
14866 control of COMPLAIN. The flag USE_SPEC_TABLE controls if we look up
14867 and insert into the specializations table or if we can assume it's
14868 the caller's responsibility; this is used by instantiate_template
14869 to avoid doing some redundant work. */
14871 static tree
14874 {
14875 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
14876 location_t saved_loc;
14884 /* Set the filename and linenumber to improve error-reporting. */
14889 {
14898 use_spec_table);
14902 {
14910 {
14911 /* If there is a local specialization that isn't a
14912 parameter pack, it means that we're doing a "simple"
14913 substitution from inside tsubst_pack_expansion. Just
14914 return the local specialization (which will be a single
14915 parm). */
14922 /* Expand the TYPE_PACK_EXPANSION that provides the types for
14923 the parameters in this function parameter pack. */
14927 {
14930 /* Zero-length parameter packs are boring. Just substitute
14931 into the chain. */
14935 }
14936 else
14937 {
14938 /* All we did was update the type. Make a note of that. */
14941 }
14942 }
14944 /* Loop through all of the parameters we'll build. When T is
14945 a function parameter pack, LEN is the number of expanded
14946 types in EXPANDED_TYPES; otherwise, LEN is 1. */
14949 {
14956 /* We're on the Ith parameter of the function parameter
14957 pack. */
14958 {
14959 /* Get the Ith type. */
14962 /* Rename the parameter to include the index. */
14965 }
14967 /* We're dealing with a normal parameter. */
14975 {
14978 else
14981 }
14992 /* Keep track of the first new parameter we
14993 generate. That's what will be returned to the
14994 caller. */
14998 /* Build a proper chain of parameters when substituting
14999 into a function parameter pack. */
15002 }
15004 /* If cp_unevaluated_operand is set, we're just looking for a
15005 single dummy parameter, so don't keep going. */
15010 /* FIRST_R contains the start of the chain we've built. */
15012 }
15016 {
15023 {
15024 /* This field is a lambda capture pack. Return a TREE_VEC of
15025 the expanded fields to instantiate_class_template_1. */
15029 {
15032 }
15033 else
15034 {
15035 /* All we did was update the type. Make a note of that. */
15038 }
15039 }
15042 {
15045 {
15049 }
15059 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
15060 number of bits. */
15065 {
15066 /* Set up DECL_TEMPLATE_INFO so that we can get at the
15067 NSDMI in perform_member_init. Still set DECL_INITIAL
15068 so that we know there is one. */
15073 }
15074 /* We don't have to set DECL_CONTEXT here; it is set by
15075 finish_member_declaration. */
15084 }
15088 }
15092 /* We reach here only for member using decls. We also need to check
15093 uses_template_parms because DECL_DEPENDENT_P is not set for a
15094 using-declaration that designates a member of the current
15095 instantiation (c++/53549). */
15098 {
15099 /* True iff this using-decl was written as a pack expansion
15100 (and a pack appeared in its scope or name). If a pack
15101 appeared in both, we expand the packs separately and
15102 manually merge them. */
15107 {
15110 in_decl);
15112 }
15113 else
15119 {
15123 {
15126 }
15130 }
15131 else
15139 {
15141 {
15146 }
15148 }
15156 {
15165 {
15168 }
15172 }
15176 }
15177 else
15178 {
15181 }
15186 {
15197 {
15198 /* If this is the canonical decl, we don't have to
15199 mess with instantiations, and often we can't (for
15200 typename, template type parms and such). Note that
15201 TYPE_NAME is not correct for the above test if
15202 we've copied the type for a typedef. */
15208 }
15210 /* Check to see if we already have the specialization we
15211 need. */
15217 {
15220 {
15222 complain,
15225 /* The context and type of an injected-class-name are
15226 the same, so we don't need to substitute both. */
15228 /* If CTX is unchanged, then T is in fact the
15229 specialization we want. That situation occurs when
15230 referencing a static data member within in its own
15231 class. We can use pointer equality, rather than
15232 same_type_p, because DECL_CONTEXT is always
15233 canonical... */
15235 /* ... unless T is a member template; in which
15236 case our caller can be willing to create a
15237 specialization of that template represented
15238 by T. */
15242 }
15245 {
15248 {
15255 }
15256 else
15258 }
15259 }
15260 else
15261 {
15263 /* Subsequent calls to pushdecl will fill this in. */
15265 /* A local variable. */
15267 /* Unless this is a reference to a static variable from an
15268 enclosing function, in which case we need to fill it in now. */
15270 {
15274 }
15276 }
15277 /* If we already have the specialization we need, there is
15278 nothing more to do. */
15280 {
15283 }
15285 /* Create a new node for the specialization we need. */
15287 {
15290 else
15300 /* Substituting the type might have recursively instantiated this
15301 same alias (c++/86171). */
15304 {
15307 }
15308 }
15313 {
15317 {
15318 /* It may seem that this case cannot occur, since:
15320 typedef void f();
15321 void g() { f x; }
15323 declares a function, not a variable. However:
15325 typedef void f();
15326 template <typename T> void g() { T t; }
15327 template void g<f>();
15329 is an attempt to declare a variable with function
15330 type. */
15332 /* R is not yet sufficiently initialized, so we
15333 just use its name. */
15336 }
15338 /* Wait until cp_finish_decl to set this again, to handle
15339 circular dependency (template/instantiate6.C). */
15344 {
15346 /* If the DECL_VALUE_EXPR is converted to the declared type,
15347 preserve the identity so that gimplify_type_sizes works. */
15353 {
15356 }
15365 else
15369 }
15373 }
15379 /* Clear out the mangled name and RTL for the instantiation. */
15385 /* The initializer must not be expanded until it is required;
15386 see [temp.inst]. */
15390 {
15396 /* Possibly limit visibility based on template args. */
15399 {
15403 }
15405 }
15408 {
15409 /* A static data member declaration is always marked
15410 external when it is declared in-class, even if an
15411 initializer is present. We mimic the non-template
15412 processing here. */
15421 }
15422 else
15423 {
15428 }
15437 /* Preserve a typedef that names a type. */
15439 {
15443 /* common_handle_aligned_attribute doesn't apply the alignment
15444 to DECL_ORIGINAL_TYPE. */
15448 }
15451 }
15456 }
15457 #undef RETURN
15459 out:
15460 /* Restore the file and line information. */
15464 }
15466 /* Substitute into the complete parameter type list PARMS. */
15468 tree
15470 tree args,
15471 tsubst_flags_t complain,
15472 tree in_decl)
15473 {
15475 }
15477 /* Substitute into the ARG_TYPES of a function type.
15478 If END is a TREE_CHAIN, leave it and any following types
15479 un-substituted. */
15481 static tree
15483 tree args,
15484 tree end,
15485 tsubst_flags_t complain,
15486 tree in_decl)
15487 {
15496 {
15497 /* For a pack expansion, perform substitution on the
15498 entire expression. Later on, we'll handle the arguments
15499 one-by-one. */
15504 /* So that we'll spin through the parameters, one by one. */
15506 else
15507 {
15508 /* We only partially substituted into the parameter
15509 pack. Our type is TYPE_PACK_EXPANSION. */
15512 }
15513 }
15514 else
15517 /* Check if a substituted type is erroneous before substituting into
15518 the rest of the chain. */
15520 {
15527 {
15529 {
15533 }
15535 }
15536 }
15538 /* We do not substitute into default arguments here. The standard
15539 mandates that they be instantiated only when needed, which is
15540 done in build_over_call. */
15543 /* Except that we do substitute default arguments under tsubst_lambda_expr,
15544 since the new op() won't have any associated template arguments for us
15545 to refer to later. */
15557 {
15561 /* Do array-to-pointer, function-to-pointer conversion, and ignore
15562 top-level qualifiers as required. */
15566 {
15567 /* We've instantiated a template before its default arguments
15568 have been parsed. This can happen for a nested template
15569 class, and is not an error unless we require the default
15570 argument in a call of this function. */
15571 remaining_arg_types
15574 remaining_arg_types);
15575 }
15576 else
15577 remaining_arg_types
15579 }
15582 }
15584 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
15585 *not* handle the exception-specification for FNTYPE, because the
15586 initial substitution of explicitly provided template parameters
15587 during argument deduction forbids substitution into the
15588 exception-specification:
15590 [temp.deduct]
15592 All references in the function type of the function template to the
15593 corresponding template parameters are replaced by the specified tem-
15594 plate argument values. If a substitution in a template parameter or
15595 in the function type of the function template results in an invalid
15596 type, type deduction fails. [Note: The equivalent substitution in
15597 exception specifications is done only when the function is instanti-
15598 ated, at which point a program is ill-formed if the substitution
15599 results in an invalid type.] */
15601 static tree
15603 tree args,
15604 tsubst_flags_t complain,
15605 tree in_decl)
15606 {
15607 tree return_type;
15610 /* The TYPE_CONTEXT is not used for function/method types. */
15613 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
15614 failure. */
15618 {
15619 /* Substitute the argument types. */
15631 {
15632 /* DR 1207: 'this' is in scope in the trailing return type. */
15634 }
15636 /* Substitute the return type. */
15640 {
15643 }
15644 }
15645 else
15646 /* Substitute the return type. */
15651 /* DR 486 clarifies that creation of a function type with an
15652 invalid return type is a deduction failure. */
15655 {
15657 {
15660 else
15662 }
15664 }
15667 {
15668 /* Substitute the argument types. */
15673 }
15675 /* Construct a new type node and return it. */
15678 }
15680 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
15681 ARGS into that specification, and return the substituted
15682 specification. If there is no specification, return NULL_TREE. */
15684 static tree
15686 tree args,
15687 tsubst_flags_t complain,
15688 tree in_decl,
15690 {
15691 tree specs;
15692 tree new_specs;
15697 {
15698 /* A noexcept-specifier. */
15703 {
15704 /* Defer instantiation of noexcept-specifiers to avoid
15705 excessive instantiations (c++/49107). */
15708 {
15709 /* We already partially instantiated this member template,
15710 so combine the new args with the old. */
15715 }
15716 else
15717 {
15720 }
15721 }
15722 else
15723 {
15725 {
15727 args);
15729 }
15731 }
15733 /* We've instantiated a template before a noexcept-specifier
15734 contained therein has been parsed. This can happen for
15735 a nested template class:
15737 struct S {
15738 template<typename> struct B { B() noexcept(...); };
15739 struct A : B<int> { ... use B() ... };
15740 };
15742 where completing B<int> will trigger instantiating the
15743 noexcept, even though we only parse it at the end of S. */
15745 {
15748 }
15749 }
15751 {
15754 else
15756 {
15757 tree spec;
15762 {
15763 /* Expand the pack expansion type. */
15766 in_decl);
15772 else
15773 {
15774 /* We're substituting into a member template, so
15775 we got a TYPE_PACK_EXPANSION back. Add that
15776 expansion and move on. */
15780 expanded_specs,
15781 complain);
15784 }
15785 }
15788 {
15791 else
15796 complain);
15797 }
15800 }
15801 }
15803 }
15805 /* Substitute through a TREE_LIST of types or expressions, handling pack
15806 expansions. */
15808 tree
15810 {
15817 ;
15819 {
15823 }
15826 else
15834 ;
15836 {
15840 }
15843 else
15850 ;
15855 else
15866 /* Determine the number of arguments. */
15868 {
15871 }
15874 else
15878 {
15886 else
15888 }
15891 }
15893 /* Take the tree structure T and replace template parameters used
15894 therein with the argument vector ARGS. IN_DECL is an associated
15895 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
15896 Issue error and warning messages under control of COMPLAIN. Note
15897 that we must be relatively non-tolerant of extensions here, in
15898 order to preserve conformance; if we allow substitutions that
15899 should not be allowed, we may allow argument deductions that should
15900 not succeed, and therefore report ambiguous overload situations
15901 where there are none. In theory, we could allow the substitution,
15902 but indicate that it should have failed, and allow our caller to
15903 make sure that the right thing happens, but we don't try to do this
15904 yet.
15906 This function is used for dealing with types, decls and the like;
15907 for expressions, use tsubst_expr or tsubst_copy. */
15909 tree
15911 {
15946 /* Reuse typedefs. We need to do this to handle dependent attributes,
15947 such as attribute aligned. */
15950 {
15954 {
15955 /* DECL represents an alias template and we want to
15956 instantiate it. */
15960 }
15964 {
15968 }
15973 else
15974 /* The typedef is from a non-template context. */
15978 {
15980 r = cp_build_qualified_type
15984 }
15985 else
15986 {
15987 /* We don't have an instantiation yet, so drop the typedef. */
15992 }
15993 }
16010 {
16014 /* Fall through. */
16040 {
16045 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
16046 needed. */
16052 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
16053 with TREE_SIDE_EFFECTS that indicates this is not an integral
16054 constant expression. */
16057 {
16060 }
16063 }
16067 {
16075 else
16077 }
16078 /* Fall through. */
16082 {
16096 {
16099 /* See through ARGUMENT_PACK_SELECT arguments. */
16102 }
16107 {
16109 /* If ARG is an argument pack, we don't actually want to
16110 perform a substitution here, because substitutions
16111 for argument packs are only done
16112 element-by-element. We can get to this point when
16113 substituting the type of a non-type template
16114 parameter pack, when that type actually contains
16115 template parameter packs from an outer template, e.g.,
16117 template<typename... Types> struct A {
16118 template<Types... Values> struct B { };
16119 }; */
16123 {
16126 /* When building concept checks for the purpose of
16127 deducing placeholders, we can end up with wildcards
16128 where types are expected. Adjust this to the deduced
16129 value. */
16137 return cp_build_qualified_type
16139 }
16141 {
16142 /* We are processing a type constructed from a
16143 template template parameter. */
16154 /* Consider this code:
16156 template <template <class> class Template>
16157 struct Internal {
16158 template <class Arg> using Bind = Template<Arg>;
16159 };
16161 template <template <class> class Template, class Arg>
16162 using Instantiate = Template<Arg>; //#0
16164 template <template <class> class Template,
16165 class Argument>
16166 using Bind =
16167 Instantiate<Internal<Template>::template Bind,
16168 Argument>; //#1
16170 When #1 is parsed, the
16171 BOUND_TEMPLATE_TEMPLATE_PARM representing the
16172 parameter `Template' in #0 matches the
16173 UNBOUND_CLASS_TEMPLATE representing the argument
16174 `Internal<Template>::template Bind'; We then want
16175 to assemble the type `Bind<Argument>' that can't
16176 be fully created right now, because
16177 `Internal<Template>' not being complete, the Bind
16178 template cannot be looked up in that context. So
16179 we need to "store" `Bind<Argument>' for later
16180 when the context of Bind becomes complete. Let's
16181 store that in a TYPENAME_TYPE. */
16185 argvec),
16186 typename_type,
16187 complain);
16189 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
16190 are resolving nested-types in the signature of a
16191 member function templates. Otherwise ARG is a
16192 TEMPLATE_DECL and is the real template to be
16193 instantiated. */
16201 complain);
16202 return cp_build_qualified_type
16204 }
16207 else
16208 /* TEMPLATE_PARM_INDEX. */
16210 }
16213 /* This can happen during the attempted tsubst'ing in
16214 unify. This means that we don't yet have any information
16215 about the template parameter in question. */
16218 /* Early in template argument deduction substitution, we don't
16219 want to reduce the level of 'auto', or it will be confused
16220 with a normal template parm in subsequent deduction.
16221 Similarly, don't reduce the level of template parameters to
16222 avoid mismatches when deducing their types. */
16226 /* If we get here, we must have been looking at a parm for a
16227 more deeply nested template. Make a new version of this
16228 template parameter, but with a lower level. */
16231 {
16236 {
16239 }
16245 /* Cache lowering a type parameter or a simple template
16246 template parameter. */
16250 {
16262 /* Propagate constraints on placeholders since they are
16263 only instantiated during satisfaction. */
16268 else
16270 }
16278 {
16280 /* We might need to substitute into the types of non-type
16281 template parameters. This also lowers the level of
16282 the ttp appropriately. */
16295 }
16298 /* OK, now substitute the type of the non-type parameter. We
16299 couldn't do it earlier because it might be an auto parameter,
16300 and we wouldn't need to if we had an argument. */
16309 }
16312 }
16318 /* We should never be tsubsting a binfo. */
16322 /* A vector of template arguments. */
16328 {
16332 /* [temp.deduct]
16334 Type deduction may fail for any of the following
16335 reasons:
16337 -- Attempting to create a pointer to reference type.
16338 -- Attempting to create a reference to a reference type or
16339 a reference to void.
16341 Core issue 106 says that creating a reference to a reference
16342 during instantiation is no longer a cause for failure. We
16343 only enforce this check in strict C++98 mode. */
16347 {
16350 /* We keep track of the last time we issued this error
16351 message to avoid spewing a ton of messages during a
16352 single bad template instantiation. */
16355 {
16360 else
16363 }
16366 }
16370 {
16372 {
16375 type);
16376 else
16378 type);
16379 }
16381 }
16383 {
16387 }
16389 /* In C++0x, during template argument substitution, when there is an
16390 attempt to create a reference to a reference type, reference
16391 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
16393 "If a template-argument for a template-parameter T names a type
16394 that is a reference to a type A, an attempt to create the type
16395 'lvalue reference to cv T' creates the type 'lvalue reference to
16396 A,' while an attempt to create the type type rvalue reference to
16397 cv T' creates the type T"
16398 */
16399 r = cp_build_reference_type
16402 else
16407 /* Will this ever be needed for TYPE_..._TO values? */
16411 }
16413 {
16416 {
16417 /* [temp.deduct]
16419 Type deduction may fail for any of the following
16420 reasons:
16422 -- Attempting to create "pointer to member of T" when T
16423 is not a class type. */
16427 }
16429 {
16433 }
16435 {
16439 }
16442 {
16443 /* The type of the implicit object parameter gets its
16444 cv-qualifiers from the FUNCTION_TYPE. */
16445 tree memptr;
16446 tree method_type
16451 complain);
16452 }
16453 else
16456 complain);
16457 }
16460 {
16461 tree fntype;
16462 tree specs;
16467 /* Substitute the exception specification. */
16475 }
16477 {
16482 /* As an optimization, we avoid regenerating the array type if
16483 it will obviously be the same as T. */
16487 /* These checks should match the ones in create_array_type_for_decl.
16489 [temp.deduct]
16491 The deduction may fail for any of the following reasons:
16493 -- Attempting to create an array with an element type that
16494 is void, a function type, or a reference type, or [DR337]
16495 an abstract class type. */
16501 {
16505 }
16518 {
16521 }
16524 }
16527 {
16530 {
16533 in_decl);
16538 {
16543 }
16545 }
16546 else
16559 {
16563 }
16565 {
16566 /* Normally, make_typename_type does not require that the CTX
16567 have complete type in order to allow things like:
16569 template <class T> struct S { typename S<T>::X Y; };
16571 But, such constructs have already been resolved by this
16572 point, so here CTX really should have complete type, unless
16573 it's a partial instantiation. */
16576 }
16578 /* FIXME: TYPENAME_IS_CLASS_P conflates 'class' vs 'struct' vs 'union'
16579 tags. TYPENAME_TYPE should probably remember the exact tag that
16580 was written. */
16581 enum tag_types tag_type
16591 {
16594 }
16597 {
16599 {
16603 else
16605 }
16607 {
16611 else
16613 }
16614 }
16616 return cp_build_qualified_type
16618 }
16621 {
16633 }
16636 {
16637 tree type;
16651 complain);
16652 }
16655 {
16656 tree type;
16673 else
16674 {
16678 /* In a template ~id could be either a complement expression
16679 or an unqualified-id naming a destructor; if instantiating
16680 it produces an expression, it's not an id-expression or
16681 member access. */
16684 }
16689 }
16692 {
16696 else
16703 }
16722 /* We should use one of the expression tsubsts for these codes. */
16728 }
16729 }
16731 /* Convenience wrapper over tsubst for substituting into the LHS
16732 of the :: scope resolution operator. */
16734 static tree
16736 {
16739 }
16741 /* OLDFNS is a lookup set of member functions from some class template, and
16742 NEWFNS is a lookup set of member functions from NEWTYPE, a specialization
16743 of that class template. Return the subset of NEWFNS which are
16744 specializations of a function from OLDFNS. */
16746 static tree
16748 {
16749 /* Record all member functions from the old lookup set OLDFNS into
16750 VISIBLE_SET. */
16754 {
16756 {
16757 /* Imprecisely handle dependent using-decl by keeping all members
16758 in the new lookup set that are defined in a base class, i.e.
16759 members that could plausibly have been introduced by this
16760 dependent using-decl.
16761 FIXME: Track which members are introduced by a dependent
16762 using-decl precisely, perhaps by performing another lookup
16763 from the substituted USING_DECL_SCOPE. */
16766 }
16767 else
16769 }
16771 /* Returns true iff (a less specialized version of) FN appeared in
16772 the old lookup set OLDFNS. */
16775 /* FN is a member function from a base class, introduced via a
16776 using-decl; if it might have been introduced by a dependent
16777 using-decl then just conservatively keep it, otherwise look
16778 in the old lookup set for FN exactly. */
16781 /* FN is a member function template from the current class;
16782 look in the old lookup set for the TEMPLATE_DECL from which
16783 it was specialized. */
16785 else
16786 /* FN is a non-template member function from the current class;
16787 look in the old lookup set for the FUNCTION_DECL from which
16788 it was specialized. */
16791 };
16796 {
16799 }
16803 /* Filter out from NEWFNS the member functions that weren't
16804 previously visible according to OLDFNS. */
16809 {
16811 filtered_size++;
16812 }
16818 }
16820 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
16821 expression on the left-hand side of the "." or "->" operator. We
16822 only do the lookup if we had a dependent BASELINK. Otherwise we
16823 adjust it onto the instantiated heirarchy. */
16825 static tree
16828 {
16840 {
16847 }
16855 {
16860 /* See maybe_dependent_member_ref. */
16862 {
16865 template_args);
16868 }
16871 /* Treat as-if non-dependent below. */
16876 complain);
16878 {
16879 /* Filter out from the new lookup set those functions which didn't
16880 appear in the original lookup set (in a less specialized form).
16881 This is needed to preserve the consistency of member lookup
16882 performed in an incomplete-class context, within which
16883 later-declared members ought to remain invisible. */
16886 binfo_type);
16888 }
16891 {
16897 }
16900 }
16901 else
16902 {
16903 /* We're going to overwrite pieces below, make a duplicate. */
16907 {
16908 /* The decl we found was from non-dependent scope, but we still need
16909 to update the binfos for the instantiated qualifying_scope. */
16913 }
16914 }
16916 /* If lookup found a single function, mark it as used at this point.
16917 (If lookup found multiple functions the one selected later by
16918 overload resolution will be marked as used at that point.) */
16920 {
16926 /* We might have instantiated an auto function. */
16928 }
16931 {
16932 /* Add back the template arguments, if present. */
16937 /* Update the conversion operator type. */
16939 }
16945 {
16947 qualifying_scope,
16948 object_type);
16950 /* We need to call adjust_result_of_qualified_name_lookup in case the
16951 destructor names a base class, but we unset BASELINK_QUALIFIED_P
16952 so that we still get virtual function binding. */
16954 }
16957 }
16959 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
16960 true if the qualified-id will be a postfix-expression in-and-of
16961 itself; false if more of the postfix-expression follows the
16962 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
16963 of "&". */
16965 static tree
16969 {
16970 tree expr;
16971 tree scope;
16972 tree name;
16974 tree template_args;
16979 /* Figure out what name to look up. */
16982 {
16991 }
16992 else
16993 {
16996 }
16998 /* Substitute into the qualifying scope. When there are no ARGS, we
16999 are just trying to simplify a non-dependent expression. In that
17000 case the qualifying scope may be dependent, and, in any case,
17001 substituting will not help. */
17004 {
17007 }
17008 else
17012 {
17014 /* We built one in tsubst_baselink. */
17016 else
17017 {
17020 template_args);
17022 QUALIFIED_NAME_IS_TEMPLATE
17024 }
17027 }
17030 {
17032 {
17033 /* A BIT_NOT_EXPR is used to represent a destructor. */
17035 {
17039 }
17040 else
17043 }
17044 else
17048 {
17050 {
17054 }
17056 }
17057 }
17060 {
17064 /* Remember that there was a reference to this entity. */
17067 }
17070 {
17076 }
17079 {
17080 /* We may be repeating a check already done during parsing, but
17081 if it was well-formed and passed then, it will pass again
17082 now, and if it didn't, we wouldn't have got here. The case
17083 we want to catch is when we couldn't tell then, and can now,
17084 namely when templ prior to substitution was an
17085 identifier. */
17091 complain);
17092 else
17094 }
17100 {
17101 expr = (adjust_result_of_qualified_name_lookup
17103 expr = (finish_qualified_id_expr
17107 }
17109 /* Expressions do not generally have reference type. */
17111 /* However, if we're about to form a pointer-to-member, we just
17112 want the referenced member referenced. */
17122 }
17124 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
17125 initializer, DECL is the substituted VAR_DECL. Other arguments are as
17126 for tsubst. */
17128 static tree
17131 {
17140 {
17142 {
17144 {
17149 }
17150 }
17152 {
17153 /* If we had an initializer but it
17154 instantiated to nothing,
17155 value-initialize the object. This will
17156 only occur when the initializer was a
17157 pack expansion where the parameter packs
17158 used in that expansion were of length
17159 zero. */
17165 }
17166 }
17169 }
17171 /* If T is a reference to a dependent member of the current instantiation C and
17172 we are trying to refer to that member in a partial instantiation of C,
17173 return a SCOPE_REF; otherwise, return NULL_TREE.
17175 This can happen when forming a C++17 deduction guide, as in PR96199. */
17177 static tree
17179 tree in_decl)
17180 {
17197 {
17206 complain);
17207 }
17212 {
17218 }
17221 {
17224 /* The TYPE_DECL for a typename has DECL_CONTEXT of the typename
17225 scope, but it doesn't need to be rewritten again. */
17229 }
17233 else
17236 }
17238 /* Like tsubst, but deals with expressions. This function just replaces
17239 template parms; to finish processing the resultant expression, use
17240 tsubst_copy_and_build or tsubst_expr. */
17242 static tree
17244 {
17246 tree r;
17260 {
17265 {
17266 /* We get here for a use of 'this' in an NSDMI. */
17270 /* This can happen for a parameter name used later in a function
17271 declaration (such as in a late-specified return type). Just
17272 make a dummy decl, since it's only used for its type. */
17275 /* Give it the template pattern as its context; its true context
17276 hasn't been instantiated yet and this is good enough for
17277 mangling. */
17279 }
17288 {
17289 tree enum_type;
17290 tree v;
17297 /* Unfortunately, we cannot just call lookup_name here.
17298 Consider:
17300 template <int I> int f() {
17301 enum E { a = I };
17302 struct S { void g() { E e = a; } };
17303 };
17305 When we instantiate f<7>::S::g(), say, lookup_name is not
17306 clever enough to find f<7>::a. */
17307 enum_type
17317 /* We didn't find the name. That should never happen; if
17318 name-lookup found it during preliminary parsing, we
17319 should find it again here during instantiation. */
17321 }
17326 {
17327 tree ctx;
17332 {
17335 {
17339 }
17341 }
17342 }
17351 {
17352 /* Local specialization will usually have been created when
17353 we instantiated the DECL_EXPR_DECL. */
17356 {
17357 /* We're in a generic lambda referencing a local extern
17358 from an outer block-scope of a non-template. */
17361 }
17362 }
17365 {
17368 {
17369 /* First try name lookup to find the instantiation. */
17372 {
17374 {
17375 /* During error-recovery we may find a non-variable,
17376 even an OVERLOAD: just bail out and avoid ICEs and
17377 duplicate diagnostics (c++/62207). */
17380 }
17382 {
17383 /* Make sure the one we found is the one we want. */
17387 }
17388 }
17392 else
17393 {
17394 /* This can happen for a variable used in a
17395 late-specified return type of a local lambda, or for a
17396 local static or constant. Building a new VAR_DECL
17397 should be OK in all those cases. */
17400 /* Avoid infinite recursion (79640). */
17403 {
17404 /* We can't call cp_finish_decl, so handle the
17405 initializer by hand. */
17420 }
17422 || processing_contract_condition
17429 }
17430 /* Remember this for subsequent uses. */
17433 }
17436 }
17437 else
17461 {
17462 /* Template template argument like the following example need
17463 special treatment:
17465 template <template <class> class TT> struct C {};
17466 template <class T> struct D {
17467 template <class U> struct E {};
17468 C<E> c; // #1
17469 };
17470 D<int> d; // #2
17472 We are processing the template argument `E' in #1 for
17473 the template instantiation #2. Originally, `E' is a
17474 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
17475 have to substitute this with one having context `D<int>'. */
17480 }
17481 else
17482 /* Ordinary template template argument. */
17487 {
17488 /* Handle location wrappers by substituting the wrapped node
17489 first, *then* reusing the resulting type. Doing the type
17490 first ensures that we handle template parameters and
17491 parameter pack expansions. */
17493 {
17497 }
17499 /* force_paren_expr can also create a VIEW_CONVERT_EXPR. */
17501 {
17506 }
17507 /* We shouldn't see any other uses of these in templates
17508 (tsubst_copy_and_build handles C++20 tparm object wrappers). */
17510 }
17518 CASE_CONVERT:
17519 {
17526 }
17529 {
17535 }
17540 {
17549 /* We only want to compute the number of arguments. */
17552 else
17559 {
17561 /* Set TREE_USED for the benefit of -Wunused. */
17565 }
17573 {
17578 else
17586 else
17591 }
17592 else
17594 }
17596 {
17604 }
17605 /* Fall through */
17621 {
17627 /* For addresses of immediate functions ensure we have EXPR_LOCATION
17628 set for possible later diagnostics. */
17635 }
17638 {
17642 {
17645 }
17647 }
17650 {
17651 tree object;
17652 tree name;
17657 {
17661 }
17664 {
17674 }
17679 in_decl);
17680 else
17683 }
17719 {
17723 }
17726 {
17731 }
17734 {
17738 }
17741 {
17749 }
17755 {
17762 }
17765 {
17772 }
17775 {
17782 }
17785 {
17786 /* Substituted template arguments */
17796 else
17798 }
17801 {
17821 }
17829 /* Fall through. */
17832 {
17835 }
17836 else
17840 /* This is handled by tsubst_copy_and_build. */
17844 {
17848 }
17851 /* We shouldn't have built any of these during initial template
17852 generation. Instead, they should be built during instantiation
17853 in response to the saved STMT_IS_FULL_EXPR_P setting. */
17857 {
17867 }
17885 {
17886 /* Instantiate any typedefs in the type. */
17891 }
17894 {
17898 {
17901 }
17903 }
17906 /* These can sometimes show up in a partial instantiation, but never
17907 involve template parms. */
17923 /* ??? There's no point in copying it for now, but maybe some
17924 day it will contain more information, such as a pointer back
17925 to the containing function, inlined copy or so. */
17932 /* We shouldn't get here, but keep going if !flag_checking. */
17936 }
17937 }
17939 /* Helper function for tsubst_omp_clauses, used for instantiation of
17940 OMP_CLAUSE_DECL of clauses. */
17942 static tree
17945 {
17949 /* Handle OpenMP iterators. */
17953 {
17954 tree ret;
17957 else
17958 {
17962 {
17976 }
17980 }
17984 }
17986 /* Handle an OpenMP array section represented as a TREE_LIST (or
17987 OMP_CLAUSE_DOACROSS_KIND). An OMP_CLAUSE_DOACROSS (with a depend
17988 kind of OMP_CLAUSE_DOACROSS_SINK) can also be represented as a
17989 TREE_LIST. We can handle it exactly the same as an array section
17990 (purpose, value, and a chain), even though the nomenclature
17991 (low_bound, length, etc) is different. */
17993 {
17994 tree low_bound
18007 }
18009 /* Undo convert_from_reference tsubst_expr could have called. */
18015 }
18017 /* Like tsubst_copy, but specifically for OpenMP clauses. */
18019 static tree
18022 {
18028 {
18034 {
18037 {
18043 }
18044 /* FALLTHRU */
18074 /* FALLTHRU */
18107 {
18110 {
18117 }
18118 else
18120 }
18147 {
18150 }
18155 else
18186 }
18189 {
18206 /* tsubst_expr on SCOPE_REF results in returning
18207 finish_non_static_data_member result. Undo that here. */
18211 {
18216 {
18220 CASE_CONVERT:
18229 /* FALLTHRU */
18233 }
18234 }
18240 {
18243 {
18246 }
18247 }
18251 }
18252 }
18256 {
18261 {
18264 }
18265 }
18267 }
18269 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
18271 static tree
18273 tree in_decl)
18274 {
18275 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
18293 {
18296 else
18297 {
18301 }
18302 }
18307 #undef RECUR
18308 }
18310 /* Used to temporarily communicate the list of #pragma omp parallel
18311 clauses to #pragma omp for instantiation if they are combined
18312 together. */
18319 /* Substitute one OMP_FOR iterator. */
18321 static bool
18325 {
18326 #define RECUR(NODE) \
18327 tsubst_expr ((NODE), args, complain, in_decl)
18339 {
18342 {
18347 {
18357 else
18359 {
18361 {
18367 }
18370 }
18371 }
18372 }
18376 }
18378 {
18379 /* We need to jump through some hoops to handle declarations in the
18380 init-statement, since we might need to handle auto deduction,
18381 but we need to keep control of initialization. */
18385 }
18386 else
18387 {
18389 {
18392 {
18396 {
18400 CASE_CONVERT:
18408 {
18411 }
18412 /* FALLTHRU */
18416 }
18417 }
18418 }
18419 else
18421 }
18423 {
18429 }
18430 else
18434 {
18440 NULL_TREE);
18441 else
18443 }
18446 {
18453 {
18458 }
18461 }
18471 {
18473 {
18474 /* Declare the variable, but don't let that initialize it. */
18479 }
18482 {
18486 {
18495 }
18496 else
18500 {
18505 }
18506 else
18510 }
18516 }
18519 {
18520 /* Declare and initialize the variable. */
18523 }
18525 {
18530 {
18532 {
18538 {
18541 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
18546 }
18549 {
18551 decl);
18553 }
18556 {
18558 decl);
18560 }
18561 else
18563 }
18566 }
18568 {
18571 ? OMP_CLAUSE_LASTPRIVATE
18576 {
18579 }
18580 }
18581 }
18584 {
18588 }
18589 else
18593 {
18604 {
18612 }
18613 else
18619 {
18625 }
18629 {
18637 }
18638 else
18644 }
18653 #undef RECUR
18654 }
18656 /* Helper function of tsubst_expr, find OMP_TEAMS inside
18657 of OMP_TARGET's body. */
18659 static tree
18661 {
18664 {
18673 }
18675 }
18677 /* Helper function for tsubst_expr. For decomposition declaration
18678 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
18679 also the corresponding decls representing the identifiers
18680 of the decomposition declaration. Return DECL if successful
18681 or error_mark_node otherwise, set *FIRST to the first decl
18682 in the list chained through DECL_CHAIN and *CNT to the number
18683 of such decls. */
18685 static tree
18689 {
18694 decl2
18699 {
18701 {
18704 }
18716 else
18717 {
18721 }
18728 {
18731 }
18732 else
18734 }
18737 }
18739 /* Return the proper local_specialization for init-capture pack DECL. */
18741 static tree
18743 {
18744 /* We handle normal pack captures by forwarding to the specialization of the
18745 captured parameter. We can't do that for pack init-captures; we need them
18746 to have their own local_specialization. We created the individual
18747 VAR_DECLs (if any) under build_capture_proxy, and we need to collect them
18748 when we process the DECL_EXPR for the pack init-capture in the template.
18749 So, how do we find them? We don't know the capture proxy pack when
18750 building the individual resulting proxies, and we don't know the
18751 individual proxies when instantiating the pack. What we have in common is
18752 the FIELD_DECL.
18754 So...when we instantiate the FIELD_DECL, we stick the result in
18755 local_specializations. Then at the DECL_EXPR we look up that result, see
18756 how many elements it has, synthesize the names, and look them up. */
18770 {
18775 }
18777 {
18782 else
18784 }
18786 }
18788 /* T is an operand of a template tree being substituted. Return whether
18789 T is dependent such that we should suppress some warnings that would
18790 make sense if the substituted expression were written directly, like
18791 template <int I> bool f() { return I == 2; }
18792 We don't want to warn when instantiating f that comparing two constants
18793 always has the same value.
18795 This is a more limited concept of dependence than instantiation-dependent;
18796 here we don't care whether substitution could fail. */
18798 static bool
18800 {
18809 }
18811 /* Like tsubst_copy for expressions, etc. but also does semantic
18812 processing. */
18814 tree
18816 {
18817 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
18818 #define RECUR(NODE) \
18819 tsubst_expr ((NODE), args, complain, in_decl)
18822 tree r;
18823 location_t loc;
18835 {
18837 {
18841 }
18870 else
18883 {
18888 }
18892 {
18894 tree init;
18900 {
18903 {
18907 {
18912 }
18914 }
18915 else
18916 {
18917 /* This is a non-dependent using-decl, and we'll have
18918 used the names it found during template parsing. We do
18919 not want to do the lookup again, because we might not
18920 find the things we found then. */
18923 /* We still need to push the bindings so that we can look up
18924 this name later. */
18927 }
18928 }
18931 {
18932 /* We're in tsubst_lambda_expr, we've already inserted a new
18933 capture proxy, so look it up and register it. */
18934 tree inst;
18936 {
18940 }
18942 {
18943 inst = (retrieve_local_specialization
18947 }
18948 else
18953 }
18960 /* Don't copy the old closure; we'll create a new one in
18961 tsubst_lambda_expr. */
18963 else
18964 {
18968 {
18969 /* By marking the declaration as instantiated, we avoid
18970 trying to instantiate it. Since instantiate_decl can't
18971 handle local variables, and since we've already done
18972 all that needs to be done, that's the right thing to
18973 do. */
18978 /* Anonymous aggregates are a special case. */
18981 {
18984 {
18988 }
18990 }
18995 {
19003 }
19004 else
19005 {
19027 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
19033 /* In a non-template function, VLA type declarations are
19034 handled in grokdeclarator; for templates, handle them
19035 now. */
19039 {
19043 asmspec_tree
19047 }
19053 }
19054 }
19055 }
19058 }
19068 {
19072 }
19077 {
19078 /* Construct another range_for, if this is not a final
19079 substitution (for inside a generic lambda of a
19080 template). Otherwise convert to a regular for. */
19082 stmt = (processing_template_decl
19099 {
19105 }
19106 else
19107 {
19113 }
19119 }
19126 {
19130 }
19136 {
19140 }
19152 {
19158 }
19161 {
19162 /* We're partially instantiating a generic lambda, but the condition
19163 of the constexpr if is still dependent. Don't substitute into the
19164 branches now, just remember the template arguments. */
19172 }
19176 {
19181 }
19182 else
19183 {
19191 }
19197 {
19207 }
19215 else
19223 else
19244 {
19250 {
19255 }
19256 }
19260 {
19262 tree label;
19269 }
19275 /* Computed goto's must be tsubst'd into. On the other hand,
19276 non-computed gotos must not be; the identifier in question
19277 will have no binding. */
19279 else
19285 {
19302 }
19307 {
19312 }
19313 else
19314 {
19319 else
19326 else
19332 else
19334 }
19338 {
19342 {
19344 /* Prevent instantiate_decl from trying to instantiate
19345 this variable. We've already done all that needs to be
19346 done. */
19349 }
19354 }
19360 {
19361 /* Local classes are not independent templates; they are
19362 instantiated along with their containing function. And this
19363 way we don't have to deal with pushing out of one local class
19364 to instantiate a member of another local class. */
19365 /* Closures are handled by the LAMBDA_EXPR. */
19369 {
19370 /* This is a partial instantiation, try again when full. */
19373 }
19387 }
19391 {
19392 tree condition;
19403 }
19410 in_decl);
19432 {
19439 }
19455 {
19469 in_decl);
19471 {
19478 }
19489 any_range_for
19496 {
19505 }
19506 else
19511 else
19518 else
19519 {
19527 }
19530 t));
19532 }
19538 /* FALLTHRU */
19548 in_decl);
19550 {
19555 }
19556 else
19557 {
19561 }
19566 {
19568 "%<#pragma omp critical%> with %<hint%> clause requires "
19571 }
19582 {
19585 {
19590 }
19591 else
19592 {
19596 }
19598 }
19599 else
19601 OMP_CLAUSE_DEPEND_INVALID,
19610 ? C_ORT_ACC
19629 {
19632 /* For combined target teams, ensure the num_teams and
19633 thread_limit clause expressions are evaluated on the host,
19634 before entering the target construct. */
19643 {
19646 tf_none);
19653 OMP_CLAUSE_FIRSTPRIVATE);
19657 }
19658 }
19695 {
19699 }
19700 else
19711 /* FALLTHRU */
19729 {
19735 {
19738 }
19740 {
19744 {
19747 }
19752 }
19753 else
19754 {
19757 }
19762 }
19763 else
19764 {
19771 {
19774 }
19777 {
19782 {
19785 }
19787 {
19791 {
19794 }
19799 }
19800 else
19801 {
19804 }
19808 }
19809 else
19810 {
19814 }
19818 }
19822 {
19828 {
19832 {
19837 }
19841 }
19842 else
19843 {
19848 }
19849 }
19853 {
19857 }
19870 /* If the first operand was a statement, we're done with it. */
19875 complain));
19891 }
19894 out:
19897 #undef RECUR
19898 #undef RETURN
19899 }
19901 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
19902 function. For description of the body see comment above
19903 cp_parser_omp_declare_reduction_exprs. */
19905 static void
19907 {
19913 tree_stmt_iterator tsi;
19924 {
19931 /* tsubsting a local var_decl leaves DECL_CONTEXT null, as we
19932 expect to be pushing it. */
19944 }
19946 {
19966 }
19967 }
19969 /* T is a postfix-expression that is not being used in a function
19970 call. Return the substituted version of T. */
19972 static tree
19974 tsubst_flags_t complain,
19975 tree in_decl)
19976 {
19980 else
19984 }
19986 /* Subroutine of tsubst_lambda_expr: add the FIELD/INIT capture pair to the
19987 LAMBDA_EXPR_CAPTURE_LIST passed in LIST. Do deduction for a previously
19988 dependent init-capture. EXPLICIT_P is true if the original list had
19989 explicit captures. */
19991 static void
19993 tsubst_flags_t complain)
19994 {
19996 {
19999 {
20003 }
20010 }
20013 }
20015 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
20016 instantiation context. Instantiating a pack expansion containing a lambda
20017 might result in multiple lambdas all based on the same lambda in the
20018 template. */
20020 tree
20022 {
20037 else
20048 {
20053 else
20065 {
20066 /* For a VLA, simply tsubsting the field type won't work, we need to
20067 go through add_capture again. XXX do we want to do this for all
20068 captures? */
20069 tree name = (get_identifier
20077 }
20084 {
20085 /* Remember these for when we've pushed local_specializations. */
20088 }
20094 {
20103 complain);
20104 }
20105 else
20106 {
20112 }
20113 }
20122 /* If we're pushed into another scope (PR105652), fix it. */
20127 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
20144 {
20147 }
20150 {
20153 }
20157 else
20158 {
20159 /* The body of a lambda-expression is not a subexpression of the
20160 enclosing expression. Parms are to have DECL_CHAIN tsubsted,
20161 which would be skipped if cp_unevaluated_operand. */
20162 cp_evaluated ev;
20164 /* Fix the type of 'this'. */
20168 tree inst = (oldtmpl
20173 {
20176 }
20182 /* Let finish_function set this. */
20188 else
20189 /* Still increment function_depth so that we don't GC in the
20190 middle of an expression. */
20200 /* Now record them for lookup_init_capture_pack. */
20203 {
20207 }
20213 {
20214 /* We might not partially instantiate some parts of the function, so
20215 copy these flags from the original template. */
20221 }
20223 /* [temp.deduct] A lambda-expression appearing in a function type or a
20224 template parameter is not considered part of the immediate context for
20225 the purposes of template argument deduction. */
20230 /* We already have a body block from start_lambda_function, we don't
20231 need another to confuse NRV (91217). */
20242 else
20245 /* The capture list was built up in reverse order; fix that now. */
20252 }
20254 out:
20260 }
20262 /* Subroutine of maybe_fold_fn_template_args. */
20264 static bool
20266 {
20269 {
20275 {
20278 }
20283 {
20287 }
20288 }
20291 }
20293 /* Try to do constant evaluation of any explicit template arguments in FN
20294 before overload resolution, to get any errors only once. Return true iff
20295 we didn't have any problems folding. */
20297 static bool
20299 {
20317 }
20319 /* Helper function for tsubst_copy_and_build CALL_EXPR and ARRAY_REF
20320 handling. */
20322 static void
20325 {
20328 {
20334 else
20335 {
20336 /* Expand the pack expansion and push each entry onto CALL_ARGS. */
20339 {
20344 {
20349 }
20350 }
20351 else
20352 /* A partial substitution. Add one entry. */
20354 }
20355 }
20356 }
20358 /* Like tsubst but deals with expressions and performs semantic
20359 analysis. */
20361 tree
20363 tree args,
20364 tsubst_flags_t complain,
20365 tree in_decl)
20366 {
20367 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
20368 #define RECUR(NODE) \
20369 tsubst_copy_and_build (NODE, args, complain, in_decl)
20372 location_t save_loc;
20381 /* N3276 decltype magic only applies to calls at the top level or on the
20382 right side of a comma. */
20387 {
20390 /* Fall through. */
20392 {
20393 tree decl;
20394 cp_id_kind idk;
20398 {
20401 }
20403 /* Look up the name. */
20406 /* By convention, expressions use ERROR_MARK_NODE to indicate
20407 failure, not NULL_TREE. */
20421 input_location);
20425 {
20429 }
20431 }
20434 {
20435 tree object;
20446 {
20451 }
20454 {
20461 /* If we built a function concept check, return the underlying
20462 template-id. So we can evaluate it as a function call. */
20467 }
20470 {
20472 complain);
20476 }
20479 {
20482 }
20483 else
20493 {
20494 /* C++20 P0846: we can encounter an IDENTIFIER_NODE here when
20495 name lookup found nothing when parsing the template name. */
20498 }
20499 else
20501 }
20504 {
20508 {
20509 /* A type conversion to reference type will be enclosed in
20510 such an indirect ref, but the substitution of the cast
20511 will have also added such an indirect ref. */
20513 }
20514 else
20523 }
20526 {
20530 }
20533 {
20537 {
20542 }
20544 /* We'll pass this to convert_nontype_argument again, we don't need
20545 to actually perform any conversion here. */
20553 flags));
20554 }
20557 {
20563 }
20570 {
20571 tree type;
20585 {
20605 }
20608 }
20611 {
20615 }
20640 {
20647 }
20650 /* convert_like should have created an IMPLICIT_CONV_EXPR. */
20661 else
20663 in_decl);
20698 {
20699 /* If either OP0 or OP1 was value- or type-dependent, suppress
20700 warnings that depend on the range of the types involved. */
20714 tree r = build_x_binary_op
20716 op0,
20718 ? ERROR_MARK
20720 op1,
20722 ? ERROR_MARK
20731 }
20734 {
20742 }
20758 {
20760 releasing_vec index_exp_list;
20762 index_exp_list);
20764 tree r;
20770 else
20775 }
20784 /* Fall through */
20787 {
20788 tree r;
20796 {
20797 /* When there are no ARGS, we are trying to evaluate a
20798 non-dependent expression from the parser. Trying to do
20799 the substitutions may not work. */
20802 }
20803 else
20804 {
20809 else
20813 }
20818 else
20823 {
20825 {
20827 {
20831 }
20832 else
20836 }
20838 }
20840 }
20843 {
20851 }
20865 {
20870 tree r = build_x_modify_expr
20874 /* TREE_NO_WARNING must be set if either the expression was
20875 parenthesized or it uses an operator such as >>= rather
20876 than plain assignment. In the former case, it was already
20877 set and must be copied. In the latter case,
20878 build_x_modify_expr sets it and it must not be reset
20879 here. */
20884 }
20889 /* Remember that there was a reference to this entity. */
20896 {
20901 tree ret;
20908 else
20909 {
20913 }
20915 /* If there was an initializer in the original tree, but it
20916 instantiated to an empty list, then we should pass a
20917 non-NULL empty vector to tell build_new that it was an
20918 empty initializer() rather than no initializer. This can
20919 only happen when the initializer is a pack expansion whose
20920 parameter packs are of length zero. */
20925 else
20926 {
20930 else
20931 {
20934 }
20935 }
20937 /* Avoid passing an enclosing decl to valid_array_size_p. */
20944 complain);
20952 }
20955 {
20961 complain));
20962 }
20965 {
20969 op0,
20973 }
20976 {
20977 tree function;
20981 tree ret;
20984 /* Internal function with no arguments. */
20988 /* When we parsed the expression, we determined whether or
20989 not Koenig lookup should be performed. */
20992 {
20995 }
20997 {
21002 }
21007 {
21008 /* Do nothing; calling tsubst_copy_and_build on an identifier
21009 would incorrectly perform unqualified lookup again.
21011 Note that we can also have an IDENTIFIER_NODE if the earlier
21012 unqualified lookup found a dependent local extern declaration
21013 (as per finish_call_expr); in that case koenig_p will be false
21014 and we do want to do the lookup again to find the substituted
21015 declaration. */
21019 /* Use tsubst_copy to substitute through the template arguments
21020 of the template-id without performing unqualified lookup of
21021 the template name. */
21023 }
21024 else
21025 {
21027 {
21033 }
21034 else
21039 /* Avoid error about taking the address of a constructor. */
21044 /* When KOENIG_P, we don't want to mark_used the callee before
21045 augmenting the overload set via ADL, so during this initial
21046 substitution we disable mark_used by setting tf_conv (68942). */
21052 }
21055 releasing_vec call_args;
21057 call_args);
21059 /* Stripped-down processing for a call in a thunk. Specifically, in
21060 the thunk template for a generic lambda. */
21062 {
21063 /* Now that we've expanded any packs, the number of call args
21064 might be different. */
21068 {
21075 }
21076 /* We aren't going to do normal overload resolution, so force the
21077 template-id to resolve. */
21080 {
21081 /* In a thunk, pass through args directly, without any
21082 conversions. */
21087 }
21089 {
21090 /* If there are no other args, just push 'this'. */
21093 else
21094 {
21095 /* Otherwise, shift the other args over to make room. */
21101 }
21102 }
21105 /* The thunk location is not interesting. */
21112 }
21114 /* We do not perform argument-dependent lookup if normal
21115 lookup finds a non-function, in accordance with the
21116 resolution of DR 218. */
21119 /* If lookup found a member function, the Koenig lookup is
21120 not appropriate, even if an unqualified-name was used
21121 to denote the function. */
21124 /* C++20 P0846: Lookup found nothing. */
21127 /* Only do this when substitution turns a dependent call
21128 into a non-dependent call. */
21140 {
21145 {
21146 /* For backwards compatibility and good diagnostics, try
21147 the unqualified lookup again if we aren't in SFINAE
21148 context. */
21155 {
21158 "and no declarations were found by "
21159 "argument-dependent lookup at the point "
21164 /* In a lambda fn, we have to be careful to not
21165 introduce new this captures. Legacy code can't
21166 be using lambdas anyway, so it's ok to be
21167 stricter. Be strict with C++20 template-id ADL too.
21168 And be strict if we're already failing anyway. */
21174 else
21178 {
21189 {
21192 "declarations in dependent base %qT are "
21198 else
21202 }
21203 else
21205 "%qD declared here, later in the "
21209 }
21212 }
21213 }
21215 {
21219 }
21220 }
21222 /* Remember that there was a reference to this entity. */
21231 /* Put back tf_decltype for the actual call. */
21236 {
21240 {
21242 "wrong number of arguments to "
21245 }
21246 else
21254 {
21256 "wrong number of arguments to "
21260 }
21264 complain);
21270 {
21272 complain);
21276 }
21281 {
21283 "wrong number of arguments to "
21286 }
21287 else
21288 {
21293 {
21296 }
21299 }
21303 /* Unsupported internal function with arguments. */
21305 }
21310 complain);
21312 {
21327 complain);
21328 else
21329 ret = (build_new_method_call
21334 complain));
21335 }
21337 {
21338 /* FUNCTION is a template-id referring to a concept definition. */
21343 /* Calls to standard and variable concepts should have been
21344 previously diagnosed. */
21347 /* Ensure the result is wrapped as a call expression. */
21349 }
21350 else
21353 koenig_p,
21354 complain);
21357 {
21363 {
21367 }
21369 /* This also suppresses -Wredundant-move. */
21371 }
21374 }
21377 {
21384 {
21386 {
21391 }
21392 else
21393 {
21398 }
21400 }
21401 else
21402 {
21405 }
21410 }
21413 {
21418 input_location));
21419 }
21425 {
21426 tree object;
21427 tree object_type;
21428 tree member;
21429 tree r;
21433 /* Remember that there was a reference to this entity. */
21444 else
21451 {
21454 }
21456 {
21458 complain);
21462 }
21466 {
21468 {
21473 {
21476 }
21478 {
21483 }
21484 }
21485 }
21488 {
21489 /* Lookup the template functions now that we know what the
21490 scope is. */
21497 {
21500 args);
21501 member = (adjust_result_of_qualified_name_lookup
21503 object_type));
21504 }
21505 else
21506 {
21508 input_location);
21510 }
21511 }
21515 {
21517 {
21521 else
21524 }
21526 }
21530 complain);
21534 }
21541 {
21548 tree r;
21557 /* We do not want to process the index of aggregate
21558 initializers as they are identifier nodes which will be
21559 looked up by digest_init. */
21563 {
21566 }
21571 {
21573 /* An identifier index is looked up in the type
21574 being initialized, not the current scope. */
21579 {
21580 /* Substitute into the pack expansion. */
21582 in_decl);
21586 ;
21588 /* Just move the argument into place. */
21590 else
21591 {
21592 /* Update the length of the final CONSTRUCTOR
21593 arguments vector, and note that we will need to
21594 copy.*/
21597 }
21598 }
21599 else
21601 }
21604 {
21609 {
21611 {
21616 }
21617 else
21619 }
21620 }
21628 {
21633 }
21637 }
21640 {
21643 {
21646 }
21647 else
21648 {
21651 }
21652 }
21657 /* Fall through */
21660 {
21662 /* ??? We're doing a subset of finish_id_expression here. */
21664 /* Replace an evaluated use of the thread_local variable with
21665 a call to its wrapper. */
21671 /* If the original type was a reference, we'll be wrapped in
21672 the appropriate INDIRECT_REF. */
21675 }
21678 {
21682 }
21685 {
21686 tree object_ptr
21692 }
21699 {
21706 }
21709 {
21718 /* If the resulting list of expression statement is empty,
21719 fold it further into void_node. */
21724 }
21727 {
21729 {
21730 /* We don't have a full set of template arguments yet; don't touch
21731 the lambda at all. */
21734 }
21738 }
21746 else
21747 /* Recreate the PAREN_EXPR from __builtin_assoc_barrier. */
21748 {
21752 }
21755 {
21760 complain));
21761 }
21764 {
21767 }
21770 /* No need to substitute further, a RANGE_EXPR will always be built
21771 with constant operands. */
21776 {
21780 /* We need to do this here as well as in tsubst_copy so we get the
21781 other tsubst_copy_and_build semantics for a PARM_DECL operand. */
21786 /* force_paren_expr can also create a VIEW_CONVERT_EXPR. */
21789 /* Otherwise, we're dealing with a wrapper to make a C++20 template
21790 parameter object const. */
21793 {
21794 /* The template argument is not const, presumably because
21795 it is still dependent, and so not the const template parm
21796 object. */
21800 {
21801 /* Don't add a wrapper to these. */
21804 }
21805 else
21806 /* Do add a wrapper otherwise (in particular, if op is
21807 another TEMPLATE_PARM_INDEX). */
21809 }
21811 }
21814 /* Handle Objective-C++ constructs, if appropriate. */
21815 {
21816 tree subst
21820 }
21822 }
21824 #undef RECUR
21825 #undef RETURN
21826 out:
21829 }
21831 /* Verify that the instantiated ARGS are valid. For type arguments,
21832 make sure that the type's linkage is ok. For non-type arguments,
21833 make sure they are constants if they are integral or enumerations.
21834 Emit an error under control of COMPLAIN, and return TRUE on error. */
21836 static bool
21838 {
21842 {
21852 }
21854 {
21855 /* [basic.link]: A name with no linkage (notably, the name
21856 of a class or enumeration declared in a local scope)
21857 shall not be used to declare an entity with linkage.
21858 This implies that names with no linkage cannot be used as
21859 template arguments
21861 DR 757 relaxes this restriction for C++0x. */
21866 {
21867 /* DR 488 makes use of a type with no linkage cause
21868 type deduction to fail. */
21870 {
21873 else
21876 }
21878 }
21879 /* In order to avoid all sorts of complications, we do not
21880 allow variably-modified types as template arguments. */
21882 {
21886 }
21887 }
21888 /* Class template and alias template arguments should be OK. */
21890 ;
21891 /* A non-type argument of integral or enumerated type must be a
21892 constant. */
21897 {
21901 }
21903 }
21905 static bool
21907 {
21912 {
21915 }
21919 }
21921 /* Call mark_used on each entity within the non-type template arguments in
21922 ARGS for an instantiation of TMPL, to ensure that each such entity is
21923 considered odr-used (and therefore marked for instantiation) regardless of
21924 whether the specialization was first formed in a template context (which
21925 inhibits mark_used).
21927 This function assumes push_to_top_level has been called beforehand. */
21929 static void
21931 {
21932 /* It suffices to do this only when instantiating a primary template. */
21936 /* We already marked outer arguments when specializing the context. */
21940 {
21941 /* A (pointer/reference to) function or variable NTTP argument. */
21944 {
21950 {
21951 /* Pass tf_none to avoid duplicate diagnostics: if this call
21952 fails then an earlier call to mark_used for this argument
21953 must have also failed and emitted a diagnostic. */
21956 }
21957 }
21958 /* A class NTTP argument. */
21961 {
21964 {
21967 }
21969 };
21972 }
21973 }
21974 }
21976 /* We're out of SFINAE context now, so generate diagnostics for the access
21977 errors we saw earlier when instantiating D from TMPL and ARGS. */
21979 static void
21981 {
21993 }
21995 /* Instantiate the indicated variable, function, or alias template TMPL with
21996 the template arguments in TARG_PTR. */
21998 tree
22000 {
22004 tree fndecl;
22005 tree gen_tmpl;
22016 /* If this function is a clone, handle it specially. */
22018 {
22019 tree spec;
22020 tree clone;
22022 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
22023 DECL_CLONED_FUNCTION. */
22029 /* Look for the clone. */
22033 /* We should always have found the clone by now. */
22036 }
22041 /* Check to see if we already have this specialization. */
22045 /* targ_ptr only has the innermost template args, so add the outer ones
22046 from tmpl, which could be either a partial instantiation or gen_tmpl (in
22047 the case of a non-dependent call within a template definition). */
22048 targ_ptr = (add_outermost_template_args
22050 targ_ptr));
22056 || ((fndecl
22062 {
22064 {
22068 }
22070 }
22073 complain))
22076 /* We are building a FUNCTION_DECL, during which the access of its
22077 parameters and return types have to be checked. However this
22078 FUNCTION_DECL which is the desired context for access checking
22079 is not built yet. We solve this chicken-and-egg problem by
22080 deferring all checks until we have the FUNCTION_DECL. */
22083 /* Instantiation of the function happens in the context of the function
22084 template, not the context of the overload resolution we're doing. */
22086 /* If there are dependent arguments, e.g. because we're doing partial
22087 ordering, make sure processing_template_decl stays set. */
22091 {
22092 tree ctx;
22094 /* If the context of the partially instantiated template is
22095 already non-dependent, then we might as well use it. */
22097 else
22101 }
22108 {
22109 /* We need to determine if we're using a partial or explicit
22110 specialization now, because the type of the variable could be
22111 different. */
22117 {
22123 }
22124 }
22126 /* Substitute template parameters to obtain the specialization. */
22134 {
22137 }
22139 /* The DECL_TI_TEMPLATE should always be the immediate parent
22140 template, not the most general template. */
22144 /* Now that we we've formed this variable template specialization,
22145 remember the result of most_specialized_partial_spec for it. */
22154 /* Now we know the specialization, compute access previously
22155 deferred. Do no access control for inheriting constructors,
22156 as we already checked access for the inherited constructor. */
22159 {
22164 }
22167 /* If we've just instantiated the main entry point for a function,
22168 instantiate all the alternate entry points as well. We do this
22169 by cloning the instantiation of the main entry point, not by
22170 instantiating the template clones. */
22176 {
22178 {
22179 /* Remember to reinstantiate when we're out of SFINAE so the user
22180 can see the errors. */
22182 }
22184 }
22187 }
22189 /* Instantiate the alias template TMPL with ARGS. Also push a template
22190 instantiation level, which instantiate_template doesn't do because
22191 functions and variables have sufficient context established by the
22192 callers. */
22194 static tree
22196 {
22205 /* FIXME check for satisfaction in check_instantiated_args. */
22207 {
22209 {
22210 auto_diagnostic_group d;
22213 }
22215 }
22223 {
22224 /* An alias template specialization can be dependent
22225 even if its underlying type is not. */
22228 /* Sometimes a dependent alias spec is equivalent to its expansion,
22229 sometimes not. So always use structural_comptypes. */
22231 }
22234 }
22236 /* PARM is a template parameter pack for FN. Returns true iff
22237 PARM is used in a deducible way in the argument list of FN. */
22239 static bool
22241 {
22244 {
22246 tree packs;
22252 {
22253 /* The template parameter pack is used in a function parameter
22254 pack. If this is the end of the parameter list, the
22255 template parameter pack is deducible. */
22258 else
22259 /* Otherwise, not. Well, it could be deduced from
22260 a non-pack parameter, but doing so would end up with
22261 a deduction mismatch, so don't bother. */
22263 }
22264 }
22265 /* The template parameter pack isn't used in any function parameter
22266 packs, but it might be used deeper, e.g. tuple<Args...>. */
22268 }
22270 /* Subroutine of fn_type_unification: check non-dependent parms for
22271 convertibility. */
22273 static int
22277 {
22278 /* Non-constructor methods need to leave a conversion for 'this', which
22279 isn't included in nargs here. */
22285 {
22291 /* For a function parameter pack that occurs at the end of the
22292 parameter-declaration-list, the type A of each remaining
22293 argument of the call is compared with the type P of the
22294 declarator-id of the function parameter pack. */
22300 /* For a function parameter pack that does not occur at the
22301 end of the parameter-declaration-list, the type of the
22302 parameter pack is a non-deduced context. */
22306 {
22314 }
22317 }
22320 }
22322 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
22323 NARGS elements of the arguments that are being used when calling
22324 it. TARGS is a vector into which the deduced template arguments
22325 are placed.
22327 Returns either a FUNCTION_DECL for the matching specialization of FN or
22328 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
22329 true, diagnostics will be printed to explain why it failed.
22331 If FN is a conversion operator, or we are trying to produce a specific
22332 specialization, RETURN_TYPE is the return type desired.
22334 The EXPLICIT_TARGS are explicit template arguments provided via a
22335 template-id.
22337 The parameter STRICT is one of:
22339 DEDUCE_CALL:
22340 We are deducing arguments for a function call, as in
22341 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
22342 deducing arguments for a call to the result of a conversion
22343 function template, as in [over.call.object].
22345 DEDUCE_CONV:
22346 We are deducing arguments for a conversion function, as in
22347 [temp.deduct.conv].
22349 DEDUCE_EXACT:
22350 We are deducing arguments when doing an explicit instantiation
22351 as in [temp.explicit], when determining an explicit specialization
22352 as in [temp.expl.spec], or when taking the address of a function
22353 template, as in [temp.deduct.funcaddr]. */
22355 tree
22357 tree explicit_targs,
22358 tree targs,
22361 tree return_type,
22362 unification_kind_t strict,
22367 {
22368 tree parms;
22369 tree fntype;
22374 /* type_unification_real will pass back any access checks from default
22375 template argument substitution. */
22377 /* We don't have all the template args yet. */
22390 full_targs = (add_outermost_template_args
22392 targs));
22397 /* In C++0x, it's possible to have a function template whose type depends
22398 on itself recursively. This is most obvious with decltype, but can also
22399 occur with enumeration scope (c++/48969). So we need to catch infinite
22400 recursion and reject the substitution at deduction time; this function
22401 will return error_mark_node for any repeated substitution.
22403 This also catches excessive recursion such as when f<N> depends on
22404 f<N-1> across all integers, and returns error_mark_node for all the
22405 substitutions back up to the initial one.
22407 This is, of course, not reentrant. */
22416 {
22417 /* [temp.deduct]
22419 The specified template arguments must match the template
22420 parameters in kind (i.e., type, nontype, template), and there
22421 must not be more arguments than there are parameters;
22422 otherwise type deduction fails.
22424 Nontype arguments must match the types of the corresponding
22425 nontype template parameters, or must be convertible to the
22426 types of the corresponding nontype parameters as specified in
22427 _temp.arg.nontype_, otherwise type deduction fails.
22429 All references in the function type of the function template
22430 to the corresponding template parameters are replaced by the
22431 specified template argument values. If a substitution in a
22432 template parameter or in the function type of the function
22433 template results in an invalid type, type deduction fails. */
22444 explicit_targs);
22446 /* Adjust any explicit template arguments before entering the
22447 substitution context. */
22448 explicit_targs
22455 /* Substitute the explicit args into the function type. This is
22456 necessary so that, for instance, explicitly declared function
22457 arguments can match null pointed constants. If we were given
22458 an incomplete set of explicit args, we must not do semantic
22459 processing during substitution as we could create partial
22460 instantiations. */
22462 {
22467 /* Dig out the actual parm. */
22470 {
22473 }
22475 {
22478 }
22481 /* No explicit argument for this template parameter. */
22484 {
22485 /* Mark the argument pack as "incomplete". We could
22486 still deduce more arguments during unification.
22487 We remove this mark in type_unification_real. */
22492 /* We have some incomplete argument packs. */
22494 }
22495 }
22498 {
22500 {
22503 }
22506 /* Ignore any access checks; we'll see them again in
22507 instantiate_template and they might have the wrong
22508 access path at this point. */
22519 }
22521 /* Place the explicitly specified arguments in TARGS. */
22527 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
22529 }
22532 {
22538 }
22543 /* Never do unification on the 'this' parameter. */
22547 {
22548 /* We're deducing for a call to the result of a template conversion
22549 function. The parms we really want are in return_type. */
22553 }
22555 {
22557 }
22559 /* We allow incomplete unification without an error message here
22560 because the standard doesn't seem to explicitly prohibit it. Our
22561 callers must be ready to deal with unification failures in any
22562 event. */
22564 /* If we aren't explaining yet, push tinst context so we can see where
22565 any errors (e.g. from class instantiations triggered by instantiation
22566 of default template arguments) come from. If we are explaining, this
22567 context is redundant. */
22569 {
22572 }
22582 /* Now that we have bindings for all of the template arguments,
22583 ensure that the arguments deduced for the template template
22584 parameters have compatible template parameter lists. We cannot
22585 check this property before we have deduced all template
22586 arguments, because the template parameter types of a template
22587 template parameter might depend on prior template parameters
22588 deduced after the template template parameter. The following
22589 ill-formed example illustrates this issue:
22591 template<typename T, template<T> class C> void f(C<5>, T);
22593 template<int N> struct X {};
22595 void g() {
22596 f(X<5>(), 5l); // error: template argument deduction fails
22597 }
22599 The template parameter list of 'C' depends on the template type
22600 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
22601 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
22602 time that we deduce 'C'. */
22605 {
22608 }
22610 deduced:
22612 /* CWG2369: Check satisfaction before non-deducible conversions. */
22614 {
22618 }
22620 /* DR 1391: All parameters have args, now check non-dependent parms for
22621 convertibility. We don't do this if all args were explicitly specified,
22622 as the standard says that we substitute explicit args immediately. */
22628 /* All is well so far. Now, check:
22630 [temp.deduct]
22632 When all template arguments have been deduced, all uses of
22633 template parameters in nondeduced contexts are replaced with
22634 the corresponding deduced argument values. If the
22635 substitution results in an invalid type, as described above,
22636 type deduction fails. */
22638 {
22641 }
22643 /* Also collect access checks from the instantiation. */
22656 /* Now perform any access checks encountered during substitution. */
22663 /* If we're looking for an exact match, check that what we got
22664 is indeed an exact match. It might not be if some template
22665 parameters are used in non-deduced contexts. But don't check
22666 for an exact match if we have dependent template arguments;
22667 in that case we're doing partial ordering, and we already know
22668 that we have two candidates that will provide the actual type. */
22670 {
22674 tree sarg
22680 {
22684 }
22686 /* add_candidates uses DEDUCE_EXACT for x.operator foo(), but args
22687 doesn't contain the trailing void, and conv fns are always (). */
22689 {
22693 }
22694 }
22696 /* After doing deduction with the inherited constructor, actually return an
22697 instantiation of the inheriting constructor. */
22703 fail:
22706 {
22708 /* Reset once we're all the way out. */
22710 }
22713 }
22715 /* Returns true iff PARM is a forwarding reference in the context of
22716 template argument deduction for TMPL. */
22718 static bool
22720 {
22721 /* [temp.deduct.call], "A forwarding reference is an rvalue reference to a
22722 cv-unqualified template parameter ..." */
22727 {
22729 /* [temp.deduct.call], "... that does not represent a template parameter
22730 of a class template (during class template argument deduction)." */
22734 {
22735 /* Since the template parameters of a synthesized guide consist of
22736 the template parameters of the class template followed by those of
22737 the constructor (if any), we can tell if PARM represents a template
22738 parameter of the class template by comparing its index with the
22739 arity of the class template. */
22744 }
22746 }
22748 }
22750 /* Adjust types before performing type deduction, as described in
22751 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
22752 sections are symmetric. PARM is the type of a function parameter
22753 or the return type of the conversion function. ARG is the type of
22754 the argument passed to the call, or the type of the value
22755 initialized with the result of the conversion function.
22756 ARG_EXPR is the original argument expression, which may be null. */
22758 static int
22760 unification_kind_t strict,
22763 tree arg_expr)
22764 {
22768 {
22773 /* [temp.deduct.conv] First remove a reference type on parm.
22774 DRs 322 & 976 affected this. */
22778 /* Swap PARM and ARG throughout the remainder of this
22779 function; the handling is precisely symmetric since PARM
22780 will initialize ARG rather than vice versa. */
22786 /* Core issue #873: Do the DR606 thing (see below) for these cases,
22787 too, but here handle it by stripping the reference from PARM
22788 rather than by adding it to ARG. */
22793 /* Nothing else to do in this case. */
22798 }
22801 {
22802 /* [temp.deduct.call]
22804 If P is not a reference type:
22806 --If A is an array type, the pointer type produced by the
22807 array-to-pointer standard conversion (_conv.array_) is
22808 used in place of A for type deduction; otherwise,
22810 --If A is a function type, the pointer type produced by
22811 the function-to-pointer standard conversion
22812 (_conv.func_) is used in place of A for type deduction;
22813 otherwise,
22815 --If A is a cv-qualified type, the top level
22816 cv-qualifiers of A's type are ignored for type
22817 deduction. */
22822 else
22824 }
22826 /* [temp.deduct.call], "If P is a forwarding reference and the argument is
22827 an lvalue, the type 'lvalue reference to A' is used in place of A for
22828 type deduction." */
22831 /* try_one_overload doesn't provide an arg_expr, but
22832 functions are always lvalues. */
22836 /* [temp.deduct.call]
22838 If P is a cv-qualified type, the top level cv-qualifiers
22839 of P's type are ignored for type deduction. If P is a
22840 reference type, the type referred to by P is used for
22841 type deduction. */
22844 {
22847 }
22850 }
22852 /* Subroutine of fn_type_unification. PARM is a function parameter of a
22853 template which doesn't contain any deducible template parameters; check if
22854 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
22855 unify_one_argument. */
22857 static int
22861 {
22862 tree type;
22866 else
22874 {
22877 }
22879 {
22883 /* Avoid recalculating this in add_function_candidate. */
22884 ok = (*conv_p
22886 else
22890 }
22894 else
22896 }
22900 /* Returns true iff the expression EXPR is one from which a template
22901 argument can be deduced. In other words, if it's an undecorated
22902 use of a template non-type parameter. */
22904 static bool
22906 {
22907 /* Strip implicit conversions and implicit INDIRECT_REFs. */
22913 }
22915 /* Returns true iff the array domain DOMAIN uses a template parameter in a
22916 deducible way; that is, if it has a max value of <PARM> - 1. */
22918 static bool
22920 {
22929 }
22931 /* Returns true iff the template arguments ARGS use a template parameter
22932 in a deducible way. */
22934 static bool
22936 {
22938 {
22942 else
22943 {
22950 else
22952 }
22955 }
22957 }
22959 /* Returns true iff TYPE contains any deducible references to template
22960 parameters, as per 14.8.2.5. */
22962 static bool
22964 {
22968 /* T
22969 cv-list T
22970 TT<T>
22971 TT<i>
22972 TT<> */
22977 /* T*
22978 T&
22979 T&& */
22983 /* T[integer-constant ]
22984 type [i] */
22989 /* T type ::*
22990 type T::*
22991 T T::*
22992 T (type ::*)()
22993 type (T::*)()
22994 type (type ::*)(T)
22995 type (T::*)(T)
22996 T (type ::*)(T)
22997 T (T::*)()
22998 T (T::*)(T) */
23001 || (uses_deducible_template_parms
23004 /* template-name <T> (where template-name refers to a class template)
23005 template-name <i> (where template-name refers to a class template) */
23012 /* type (T)
23013 T()
23014 T(T) */
23016 {
23030 }
23033 }
23035 /* Subroutine of type_unification_real and unify_pack_expansion to
23036 handle unification of a single P/A pair. Parameters are as
23037 for those functions. */
23039 static int
23043 {
23050 /* We can't deduce anything from this, but we might get all the
23051 template args from other function args. */
23054 /* Implicit conversions (Clause 4) will be performed on a function
23055 argument to convert it to the type of the corresponding function
23056 parameter if the parameter type contains no template-parameters that
23057 participate in template argument deduction. */
23060 /* For function parameters with no deducible template parameters,
23061 just return. We'll check non-dependent conversions later. */
23065 {
23067 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
23068 | UNIFY_ALLOW_MORE_CV_QUAL
23082 }
23084 /* We only do these transformations if this is the top-level
23085 parameter_type_list in a call or declaration matching; in other
23086 situations (nested function declarators, template argument lists) we
23087 won't be comparing a type to an expression, and we don't do any type
23088 adjustments. */
23090 {
23092 {
23095 {
23096 /* [temp.deduct.type] A template-argument can be
23097 deduced from a pointer to function or pointer
23098 to member function argument if the set of
23099 overloaded functions does not contain function
23100 templates and at most one of a set of
23101 overloaded functions provides a unique
23102 match. */
23106 /* If a unique match was not found, this is a
23107 non-deduced context, so we still succeed. */
23109 }
23115 }
23119 }
23120 else
23125 /* For deduction from an init-list we need the actual list. */
23129 }
23131 /* for_each_template_parm callback that always returns 0. */
23133 static int
23135 {
23137 }
23139 /* for_each_template_parm any_fn callback to handle deduction of a template
23140 type argument from the type of an array bound. */
23142 static int
23144 {
23152 {
23158 }
23160 /* Keep walking. */
23162 }
23164 /* Try to deduce any not-yet-deduced template type arguments from the type of
23165 an array bound. This is handled separately from unify because 14.8.2.5 says
23166 "The type of a type parameter is only deduced from an array bound if it is
23167 not otherwise deduced." */
23169 static void
23171 {
23176 }
23178 /* Most parms like fn_type_unification.
23180 If SUBR is 1, we're being called recursively (to unify the
23181 arguments of a function or method parameter of a function
23182 template).
23184 CHECKS is a pointer to a vector of access checks encountered while
23185 substituting default template arguments. */
23187 static int
23189 tree full_targs,
23190 tree xparms,
23194 unification_kind_t strict,
23197 {
23202 tree parms;
23213 /* Reset the number of non-defaulted template arguments contained
23214 in TARGS. */
23217 again:
23222 /* Only fn_type_unification cares about terminal void. */
23229 {
23234 /* For a function parameter pack that occurs at the end of the
23235 parameter-declaration-list, the type A of each remaining
23236 argument of the call is compared with the type P of the
23237 declarator-id of the function parameter pack. */
23243 /* For a function parameter pack that does not occur at the
23244 end of the parameter-declaration-list, the type of the
23245 parameter pack is a non-deduced context. */
23252 explain_p))
23254 }
23259 {
23260 /* Unify the remaining arguments with the pack expansion type. */
23261 tree argvec;
23264 /* Allocate a TREE_VEC and copy in all of the arguments */
23269 /* Copy the parameter into parmvec. */
23275 /* Advance to the end of the list of parameters. */
23277 }
23279 /* Fail if we've reached the end of the parm list, and more args
23280 are present, and the parm list isn't variadic. */
23283 /* Fail if parms are left and they don't have default values and
23284 they aren't all deduced as empty packs (c++/57397). This is
23285 consistent with sufficient_parms_p. */
23288 {
23292 do
23293 {
23296 count++;
23298 }
23302 type_pack_p);
23303 }
23306 {
23307 tsubst_flags_t complain = (explain_p
23308 ? tf_warning_or_error
23313 {
23317 /* Clear the "incomplete" flags on all argument packs now so that
23318 substituting them into later default arguments works. */
23320 {
23323 }
23331 {
23336 }
23338 /* If this is an undeduced nontype parameter that depends on
23339 a type parameter, try another pass; its type may have been
23340 deduced from a later argument than the one from which
23341 this parameter can be deduced. */
23346 {
23349 }
23351 /* Core issue #226 (C++0x) [temp.deduct]:
23353 If a template argument has not been deduced, its
23354 default template argument, if any, is used.
23356 When we are in C++98 mode, TREE_PURPOSE will either
23357 be NULL_TREE or ERROR_MARK_NODE, so we do not need
23358 to explicitly check cxx_dialect here. */
23360 /* OK, there is a default argument. Wait until after the
23361 conversion check to do substitution. */
23364 /* If the type parameter is a parameter pack, then it will
23365 be deduced to an empty parameter pack. */
23367 {
23368 tree arg;
23371 {
23374 }
23375 else
23382 }
23385 }
23387 /* During partial ordering, we deduce dependent template args. */
23390 /* Now substitute into the default template arguments. */
23392 {
23397 {
23401 }
23416 {
23417 /* The type of this non-type parameter depends on undeduced
23418 parameters. Don't try to use its default argument yet,
23419 since we might deduce an argument for it on the next pass,
23420 but do check whether the arguments we already have cause
23421 substitution failure, so that that happens before we try
23422 later default arguments (78489). */
23425 NULL_TREE);
23429 else
23431 }
23432 else
23433 {
23434 /* Even if the call is happening in template context, getting
23435 here means it's non-dependent, and a default argument is
23436 considered a separate definition under [temp.decls], so we can
23437 do this substitution without processing_template_decl. This
23438 is important if the default argument contains something that
23439 might be instantiation-dependent like access (87480). */
23443 {
23444 /* First instatiate in template context, in case we still
23445 depend on undeduced template parameters. */
23448 NULL_TREE);
23452 /* We replaced all the tparms, substitute again out of
23453 template context. */
23455 }
23458 NULL_TREE);
23467 }
23476 {
23478 /* The position of the first default template argument,
23479 is also the number of non-defaulted arguments in TARGS.
23480 Record that. */
23483 }
23484 }
23488 }
23494 }
23496 /* Subroutine of type_unification_real. Args are like the variables
23497 at the call site. ARG is an overloaded function (or template-id);
23498 we try deducing template args from each of the overloads, and if
23499 only one succeeds, we go with that. Modifies TARGS and returns
23500 true on success. */
23502 static bool
23504 tree targs,
23505 tree parm,
23506 tree arg,
23507 unification_kind_t strict,
23510 {
23517 {
23520 }
23521 else
23525 /* Handle `&x' where `x' is some static or non-static member
23526 function name. */
23532 /* Strip baselink information. */
23537 {
23538 /* If we got some explicit template args, we need to plug them into
23539 the affected templates before we try to unify, in case the
23540 explicit args will completely resolve the templates in question. */
23547 {
23558 {
23563 {
23564 /* Instantiate the function to deduce its return type. */
23568 }
23577 {
23580 }
23581 }
23584 }
23585 /* If no templates (or more than one) are fully resolved by the
23586 explicit arguments, this template-id is a non-deduced context; it
23587 could still be OK if we deduce all template arguments for the
23588 enclosing call through other arguments. */
23591 }
23593 /* If ARG is, for example, "(0, &f)" then its type will be unknown
23594 -- but the deduction does not succeed because the expression is
23595 not just the function on its own. */
23597 else
23599 {
23604 {
23607 }
23608 }
23610 /* [temp.deduct.type] A template-argument can be deduced from a pointer
23611 to function or pointer to member function argument if the set of
23612 overloaded functions does not contain function templates and at most
23613 one of a set of overloaded functions provides a unique match.
23615 So if we found multiple possibilities, we return success but don't
23616 deduce anything. */
23619 {
23623 {
23628 /* Don't forget explicit template arguments in a pack. */
23632 }
23633 }
23638 }
23640 /* Core DR 115: In contexts where deduction is done and fails, or in
23641 contexts where deduction is not done, if a template argument list is
23642 specified and it, along with any default template arguments, identifies
23643 a single function template specialization, then the template-id is an
23644 lvalue for the function template specialization. */
23646 tree
23648 {
23661 {
23664 }
23666 {
23669 }
23671 {
23674 }
23677 {
23681 /* If we got some explicit template args, we need to plug them into
23682 the affected templates before we try to unify, in case the
23683 explicit args will completely resolve the templates in question. */
23691 {
23702 {
23705 {
23708 }
23711 {
23714 }
23715 }
23716 }
23718 {
23726 {
23727 tree base
23730 }
23734 }
23736 /* There were no good options and at least one bad one, so let the
23737 user know what the problem is. */
23739 }
23741 }
23743 /* As above, but error out if the expression remains overloaded. */
23745 tree
23747 {
23750 {
23754 }
23756 }
23758 /* Subroutine of resolve_overloaded_unification; does deduction for a single
23759 overload. Fills TARGS with any deduced arguments, or error_mark_node if
23760 different overloads deduce different arguments for a given parm.
23761 ADDR_P is true if the expression for which deduction is being
23762 performed was of the form "& fn" rather than simply "fn".
23764 Returns 1 on success. */
23766 static int
23768 tree orig_targs,
23769 tree targs,
23770 tree parm,
23771 tree arg,
23772 unification_kind_t strict,
23776 {
23778 tree tempargs;
23784 /* [temp.deduct.type] A template-argument can be deduced from a pointer
23785 to function or pointer to member function argument if the set of
23786 overloaded functions does not contain function templates and at most
23787 one of a set of overloaded functions provides a unique match.
23789 So if this is a template, just return success. */
23802 /* We don't copy orig_targs for this because if we have already deduced
23803 some template args from previous args, unify would complain when we
23804 try to deduce a template parameter for the same argument, even though
23805 there isn't really a conflict. */
23812 /* First make sure we didn't deduce anything that conflicts with
23813 explicitly specified args. */
23815 {
23822 /* Since we're unifying against ourselves, we will fill in
23823 template args used in the function parm list with our own
23824 template parms. Discard them. */
23827 {
23828 /* Check that the argument at each index of the deduced argument pack
23829 is equivalent to the corresponding explicitly specified argument.
23830 We may have deduced more arguments than were explicitly specified,
23831 and that's OK. */
23833 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
23834 that's wrong if we deduce the same argument pack from multiple
23835 function arguments: it's only incomplete the first time. */
23848 }
23851 }
23854 {
23859 }
23862 }
23864 /* PARM is a template class (perhaps with unbound template
23865 parameters). ARG is a fully instantiated type. If ARG can be
23866 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
23867 TARGS are as for unify. */
23869 static tree
23872 {
23881 /* We need to make a new template argument vector for the call to
23882 unify. If we used TARGS, we'd clutter it up with the result of
23883 the attempted unification, even if this class didn't work out.
23884 We also don't want to commit ourselves to all the unifications
23885 we've already done, since unification is supposed to be done on
23886 an argument-by-argument basis. In other words, consider the
23887 following pathological case:
23889 template <int I, int J, int K>
23890 struct S {};
23892 template <int I, int J>
23893 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
23895 template <int I, int J, int K>
23896 void f(S<I, J, K>, S<I, I, I>);
23898 void g() {
23899 S<0, 0, 0> s0;
23900 S<0, 1, 2> s2;
23902 f(s0, s2);
23903 }
23905 Now, by the time we consider the unification involving `s2', we
23906 already know that we must have `f<0, 0, 0>'. But, even though
23907 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
23908 because there are two ways to unify base classes of S<0, 1, 2>
23909 with S<I, I, I>. If we kept the already deduced knowledge, we
23910 would reject the possibility I=1. */
23918 else
23923 }
23925 /* Given a template type PARM and a class type ARG, find the unique
23926 base type in ARG that is an instance of PARM. We do not examine
23927 ARG itself; only its base-classes. If there is not exactly one
23928 appropriate base class, return NULL_TREE. PARM may be the type of
23929 a partial specialization, as well as a plain template type. Used
23930 by unify. */
23932 static enum template_base_result
23935 {
23937 tree binfo;
23943 {
23944 /* The type could not be completed. */
23947 }
23949 /* Walk in inheritance graph order. The search order is not
23950 important, and this avoids multiple walks of virtual bases. */
23952 {
23957 {
23958 /* If there is more than one satisfactory baseclass, then:
23960 [temp.deduct.call]
23962 If they yield more than one possible deduced A, the type
23963 deduction fails.
23965 applies. */
23967 {
23968 /* [temp.deduct.call]/4.3: If there is a class C that is a
23969 (direct or indirect) base class of D and derived (directly or
23970 indirectly) from a class B and that would be a valid deduced
23971 A, the deduced A cannot be B or pointer to B, respectively. */
23973 /* Ignore r. */
23977 else
23978 {
23981 }
23982 }
23985 }
23986 }
23990 }
23992 /* Returns the level of DECL, which declares a template parameter. */
23994 static int
23996 {
23998 {
24008 }
24010 }
24012 /* Decide whether ARG can be unified with PARM, considering only the
24013 cv-qualifiers of each type, given STRICT as documented for unify.
24014 Returns nonzero iff the unification is OK on that basis. */
24016 static int
24018 {
24024 {
24025 /* Although a CVR qualifier is ignored when being applied to a
24026 substituted template parameter ([8.3.2]/1 for example), that
24027 does not allow us to unify "const T" with "int&" because both
24028 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
24029 It is ok when we're allowing additional CV qualifiers
24030 at the outer level [14.8.2.1]/3,1st bullet. */
24039 }
24050 }
24052 /* Determines the LEVEL and INDEX for the template parameter PARM. */
24053 void
24055 {
24059 {
24062 }
24063 else
24064 {
24067 }
24068 }
24070 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
24071 do { \
24072 if (unify (TP, TA, P, A, S, EP)) \
24073 return 1; \
24074 } while (0)
24076 /* Unifies the remaining arguments in PACKED_ARGS with the pack
24077 expansion at the end of PACKED_PARMS. Returns 0 if the type
24078 deduction succeeds, 1 otherwise. STRICT is the same as in
24079 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
24080 function call argument list. We'll need to adjust the arguments to make them
24081 types. SUBR tells us if this is from a recursive call to
24082 type_unification_real, or for comparing two template argument
24083 lists. */
24085 static int
24089 {
24090 tree parm
24096 /* Add in any args remembered from an earlier partial instantiation. */
24104 /* Determine the parameter packs we will be deducing from the
24105 pattern, and record their current deductions. */
24108 {
24112 /* Only template parameter packs can be deduced, not e.g. function
24113 parameter packs or __bases or __integer_pack. */
24117 /* Determine the index and level of this parameter pack. */
24122 /* Keep track of the parameter packs and their corresponding
24123 argument packs. */
24126 }
24128 /* Loop through all of the arguments that have not yet been
24129 unified and unify each with the pattern. */
24131 {
24132 tree parm;
24136 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
24137 or the element of its argument pack at the current index if
24138 this argument was explicitly specified. */
24140 {
24149 {
24152 }
24154 }
24156 /* If we had explicit template arguments, substitute them into the
24157 pattern before deduction. */
24159 {
24160 /* Some arguments might still be unspecified or dependent. */
24168 NULL_TREE);
24173 }
24174 else
24177 /* Unify the pattern with the current argument. */
24179 explain_p))
24182 /* For each parameter pack, collect the deduced value. */
24184 {
24190 }
24191 }
24193 /* Verify that the results of unification with the parameter packs
24194 produce results consistent with what we've seen before, and make
24195 the deduced argument packs available. */
24197 {
24204 /* By default keep the original deduced argument pack.
24205 If necessary, more specific code is going to update the
24206 resulting deduced argument later down in this function. */
24210 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
24211 actually deduce anything. */
24219 {
24220 /* If we had fewer function args than explicit template args,
24221 just use the explicits. */
24226 }
24229 {
24230 tree result;
24231 /* Build the deduced *_ARGUMENT_PACK. */
24233 {
24236 }
24237 else
24242 /* Note the deduced argument packs for this parameter
24243 pack. */
24245 }
24249 {
24250 /* We only had the explicitly-provided arguments before, but
24251 now we have a complete set of arguments. */
24257 }
24258 else
24259 {
24263 /* During template argument deduction for the aggregate deduction
24264 candidate, the number of elements in a trailing parameter pack
24265 is only deduced from the number of remaining function
24266 arguments if it is not otherwise deduced. */
24269 /* FIXME This isn't set properly for partial instantiations. */
24275 /* Inconsistent unification of this parameter pack. */
24277 bad_old_arg,
24278 bad_new_arg);
24279 }
24280 }
24283 }
24285 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
24286 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
24287 parameters and return value are as for unify. */
24289 static int
24293 {
24294 tree parm_max;
24295 tree arg_max;
24299 /* Our representation of array types uses "N - 1" as the
24300 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
24301 not an integer constant. We cannot unify arbitrarily
24302 complex expressions, so we eliminate the MINUS_EXPRs
24303 here. */
24307 {
24310 }
24314 {
24315 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
24316 trying to unify the type of a variable with the type
24317 of a template parameter. For example:
24319 template <unsigned int N>
24320 void f (char (&) [N]);
24321 int g();
24322 void h(int i) {
24323 char a[g(i)];
24324 f(a);
24325 }
24327 Here, the type of the ARG will be "int [g(i)]", and
24328 may be a SAVE_EXPR, etc. */
24332 }
24334 /* If only one of the bounds used a MINUS_EXPR, compensate
24335 by adding one to the other bound. */
24338 integer_type_node,
24339 parm_max,
24340 integer_one_node);
24343 integer_type_node,
24344 arg_max,
24345 integer_one_node);
24349 }
24351 /* Returns whether T, a P or A in unify, is a type, template or expression. */
24355 static pa_kind_t
24357 {
24366 else
24368 }
24370 /* Deduce the value of template parameters. TPARMS is the (innermost)
24371 set of template parameters to a template. TARGS is the bindings
24372 for those template parameters, as determined thus far; TARGS may
24373 include template arguments for outer levels of template parameters
24374 as well. PARM is a parameter to a template function, or a
24375 subcomponent of that parameter; ARG is the corresponding argument.
24376 This function attempts to match PARM with ARG in a manner
24377 consistent with the existing assignments in TARGS. If more values
24378 are deduced, then TARGS is updated.
24380 Returns 0 if the type deduction succeeds, 1 otherwise. The
24381 parameter STRICT is a bitwise or of the following flags:
24383 UNIFY_ALLOW_NONE:
24384 Require an exact match between PARM and ARG.
24385 UNIFY_ALLOW_MORE_CV_QUAL:
24386 Allow the deduced ARG to be more cv-qualified (by qualification
24387 conversion) than ARG.
24388 UNIFY_ALLOW_LESS_CV_QUAL:
24389 Allow the deduced ARG to be less cv-qualified than ARG.
24390 UNIFY_ALLOW_DERIVED:
24391 Allow the deduced ARG to be a template base class of ARG,
24392 or a pointer to a template base class of the type pointed to by
24393 ARG.
24394 UNIFY_ALLOW_INTEGER:
24395 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
24396 case for more information.
24397 UNIFY_ALLOW_OUTER_LEVEL:
24398 This is the outermost level of a deduction. Used to determine validity
24399 of qualification conversions. A valid qualification conversion must
24400 have const qualified pointers leading up to the inner type which
24401 requires additional CV quals, except at the outer level, where const
24402 is not required [conv.qual]. It would be normal to set this flag in
24403 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
24404 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
24405 This is the outermost level of a deduction, and PARM can be more CV
24406 qualified at this point.
24407 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
24408 This is the outermost level of a deduction, and PARM can be less CV
24409 qualified at this point. */
24411 static int
24414 {
24416 tree targ;
24417 tree tparm;
24419 tsubst_flags_t complain = (explain_p
24420 ? tf_warning_or_error
24423 /* I don't think this will do the right thing with respect to types.
24424 But the only case I've seen it in so far has been array bounds, where
24425 signedness is the only information lost, and I think that will be
24426 okay. VIEW_CONVERT_EXPR can appear with class NTTP, thanks to
24427 finish_id_expression_1, and are also OK. */
24435 /* We can't deduce anything from this, but we might get all the
24436 template args from other function args. */
24442 /* If PARM uses template parameters, then we can't bail out here,
24443 even if ARG == PARM, since we won't record unifications for the
24444 template parameters. We might need them if we're trying to
24445 figure out which of two things is more specialized. */
24449 /* Handle init lists early, so the rest of the function can assume
24450 we're dealing with a type. */
24452 {
24453 tree elttype;
24458 /* We can only deduce from an initializer list argument if the
24459 parameter is std::initializer_list or an array; otherwise this
24460 is a non-deduced context. */
24465 else
24466 {
24468 /* Deduction is defined in terms of a single type, so just punt
24469 on the (bizarre) std::initializer_list<T...>. */
24472 }
24477 /* If ELTTYPE has no deducible template parms, skip deduction from
24479 else
24481 {
24489 {
24493 /* It should only be possible to get here for a call. */
24495 elt_strict |= maybe_adjust_types_for_deduction
24498 }
24501 explain_p);
24502 }
24506 {
24507 /* Also deduce from the length of the initializer list. */
24514 }
24516 /* If the std::initializer_list<T> deduction worked, replace the
24517 deduced A with std::initializer_list<A>. */
24519 {
24524 }
24526 }
24528 /* If parm and arg aren't the same kind of thing (template, type, or
24529 expression), fail early. */
24533 /* Immediately reject some pairs that won't unify because of
24534 cv-qualification mismatches. */
24537 /* It is the elements of the array which hold the cv quals of an array
24538 type, and the elements might be template type parms. We'll check
24539 when we recurse. */
24541 /* We check the cv-qualifiers when unifying with template type
24542 parameters below. We want to allow ARG `const T' to unify with
24543 PARM `T' for example, when computing which of two templates
24544 is more specialized, for example. */
24553 /* PMFs recurse at the same level, so don't strip this yet. */
24561 {
24565 /* In a type which contains a nested-name-specifier, template
24566 argument values cannot be deduced for template parameters used
24567 within the nested-name-specifier. */
24579 /* The PARM is not one we're trying to unify. Just check
24580 to see if it matches ARG. */
24581 {
24586 else
24588 }
24595 /* Check for mixed types and values. */
24603 {
24606 {
24607 /* First try to match ARG directly. */
24609 explain_p);
24611 {
24612 /* Otherwise, look for a suitable base of ARG, as below. */
24619 }
24620 }
24621 /* ARG must be constructed from a template class or a template
24622 template parameter. */
24627 /* Deduce arguments T, i from TT<T> or TT<i>. */
24633 /* If the template is a template template parameter, use the
24634 TEMPLATE_TEMPLATE_PARM for matching. */
24637 /* Fall through to deduce template name. */
24638 }
24642 {
24643 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
24645 /* Simple cases: Value already set, does match or doesn't. */
24650 }
24651 else
24652 {
24653 /* If PARM is `const T' and ARG is only `int', we don't have
24654 a match unless we are allowing additional qualification.
24655 If ARG is `const int' and PARM is just `T' that's OK;
24656 that binds `const int' to `T'. */
24661 /* Consider the case where ARG is `const volatile int' and
24662 PARM is `const T'. Then, T should be `volatile int'. */
24663 arg = cp_build_qualified_type
24668 /* Simple cases: Value already set, does match or doesn't. */
24674 /* Make sure that ARG is not a variable-sized array. (Note
24675 that were talking about variable-sized arrays (like
24676 `int[n]'), rather than arrays of unknown size (like
24677 `int[]').) We'll get very confused by such a type since
24678 the bound of the array is not constant, and therefore
24679 not mangleable. Besides, such types are not allowed in
24680 ISO C++, so we can do as we please here. We do allow
24681 them for 'auto' deduction, since that isn't ABI-exposed. */
24685 /* Strip typedefs as in convert_template_argument. */
24687 }
24689 /* If ARG is a parameter pack or an expansion, we cannot unify
24690 against it unless PARM is also a parameter pack. */
24695 /* If the argument deduction results is a METHOD_TYPE,
24696 then there is a problem.
24697 METHOD_TYPE doesn't map to any real C++ type the result of
24698 the deduction cannot be of that type. */
24712 {
24713 /* The PARM is not one we're trying to unify. Just check
24714 to see if it matches ARG. */
24720 }
24726 {
24730 /* We're deducing from an array bound, the type doesn't matter.
24731 This conversion should match the one below. */
24737 }
24739 /* [temp.deduct.type] If, in the declaration of a function template
24740 with a non-type template-parameter, the non-type
24741 template-parameter is used in an expression in the function
24742 parameter-list and, if the corresponding template-argument is
24743 deduced, the template-argument type shall match the type of the
24744 template-parameter exactly, except that a template-argument
24745 deduced from an array bound may be of any integral type.
24746 The non-type parameter might use already deduced type parameters. */
24749 /* We don't have enough levels of args to do any substitution. This
24751 else
24752 {
24758 {
24761 LOOKUP_NORMAL,
24765 }
24766 }
24770 /* Template-parameter dependent expression. Just accept it for now.
24771 It will later be processed in convert_template_argument. */
24772 ;
24776 /* OK. Ignore top-level quals here because a class-type template
24780 /* Convert the ARG to the type of PARM; the deduced non-type
24781 template argument must exactly match the types of the
24782 corresponding parameter. This conversion should match the
24783 one above. */
24786 {
24787 /* We haven't deduced the type of this parameter yet. */
24789 /* We deduce from array bounds in try_array_deduction. */
24792 {
24793 /* Deduce it from the non-type argument. As above, ignore
24794 top-level quals here too. */
24799 /* Now check whether the type of this parameter is still
24800 dependent, and give up if so. */
24806 }
24807 else
24808 /* Try again later. */
24810 }
24811 else
24814 /* If ARG is a parameter pack or an expansion, we cannot unify
24815 against it unless PARM is also a parameter pack. */
24820 {
24823 }
24828 {
24829 /* A pointer-to-member constant can be unified only with
24830 another constant. */
24834 /* Just unify the class member. It would be useless (and possibly
24835 wrong, depending on the strict flags) to unify also
24836 PTRMEM_CST_CLASS, because we want to be sure that both parm and
24837 arg refer to the same variable, even if through different
24838 classes. For instance:
24840 struct A { int x; };
24841 struct B : A { };
24843 Unification of &A::x and &B::x must succeed. */
24846 }
24849 {
24853 /* [temp.deduct.call]
24855 A can be another pointer or pointer to member type that can
24856 be converted to the deduced A via a qualification
24857 conversion (_conv.qual_).
24859 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
24860 This will allow for additional cv-qualification of the
24861 pointed-to types if appropriate. */
24864 /* The derived-to-base conversion only persists through one
24865 level of pointers. */
24870 }
24903 /* We have already checked cv-qualification at the top of the
24904 function. */
24908 /* As far as unification is concerned, this wins. Later checks
24909 will invalidate it if necessary. */
24912 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
24913 /* Type INTEGER_CST can come from ordinary constant template args. */
24925 {
24935 /* Check for pack expansions in the parameters. */
24937 {
24939 {
24941 /* We can unify against something with a trailing
24942 parameter pack. */
24944 else
24945 /* [temp.deduct.type]/9: If the template argument list of
24946 P contains a pack expansion that is not the last
24947 template argument, the entire template argument list
24948 is a non-deduced context. */
24950 }
24951 }
24953 /* If we don't have enough arguments to satisfy the parameters
24954 (not counting the pack expression at the end), or we have
24955 too many arguments for a parameter list that doesn't end in
24956 a pack expression, we can't unify. */
24962 /* Unify all of the parameters that precede the (optional)
24963 pack expression. */
24965 {
24970 }
24973 DEDUCE_EXACT,
24976 }
24984 {
24992 }
24997 {
25001 {
25002 /* First, we try to unify the PARM and ARG directly. */
25007 {
25008 /* Fallback to the special case allowed in
25009 [temp.deduct.call]:
25011 If P is a class, and P has the form
25012 template-id, then A can be a derived class of
25013 the deduced A. Likewise, if P is a pointer to
25014 a class of the form template-id, A can be a
25015 pointer to a derived class pointed to by the
25016 deduced A. */
25022 {
25023 /* Don't give the derived diagnostic if we're
25024 already dealing with the same template. */
25025 bool same_template
25031 }
25032 }
25033 }
25037 /* Perhaps PARM is something like S<U> and ARG is S<int>.
25038 Then, we should unify `int' and `U'. */
25040 else
25041 /* There's no chance of unification succeeding. */
25046 }
25053 {
25056 tree a;
25062 /* CV qualifications for methods can never be deduced, they must
25063 match exactly. We need to check them explicitly here,
25064 because type_unification_real treats them as any other
25065 cv-qualified parameter. */
25067 && (!check_cv_quals_for_unify
25095 {
25105 else
25106 {
25109 /* Here "less cv-qual" means the deduced arg (i.e. parm) has
25110 /more/ noexcept, since function pointer conversions are the
25111 reverse of qualification conversions. */
25116 else
25118 }
25119 }
25121 {
25122 /* As for noexcept. */
25129 else
25131 }
25134 }
25137 /* Unify a pointer to member with a pointer to member function, which
25138 deduces the type of the member as a function type. */
25140 {
25141 /* Check top-level cv qualifiers */
25149 /* Determine the type of the function we are unifying against. */
25153 }
25172 /* Matched cases are handled by the ARG == PARM test above. */
25176 /* We might get a variable as a non-type template argument in parm if the
25177 corresponding parameter is type-dependent. Make any necessary
25178 adjustments based on whether arg is a reference. */
25182 {
25187 }
25188 /* Now use the normal expression code to check whether they match. */
25199 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
25200 or TRAIT_TYPE nodes. */
25204 /* Unification fails if we hit an error node. */
25209 {
25219 }
25220 /* FALLTHRU */
25223 /* An unresolved overload is a nondeduced context. */
25229 expr:
25230 /* We must be looking at an expression. This can happen with
25231 something like:
25233 template <int I>
25234 void foo(S<I>, S<I + 2>);
25236 or
25238 template<typename T>
25239 void foo(A<T, T{}>);
25241 This is a "non-deduced context":
25243 [deduct.type]
25245 The non-deduced contexts are:
25247 --A non-type template argument or an array bound in which
25248 a subexpression references a template parameter.
25250 In these cases, we assume deduction succeeded, but don't
25251 actually infer any unifications. */
25256 else
25258 }
25259 }
25260 #undef RECUR_AND_CHECK_FAILURE
25261 \f
25262 /* Note that DECL can be defined in this translation unit, if
25263 required. */
25265 static void
25267 {
25268 tree clone;
25272 }
25274 /* Called if RESULT is explicitly instantiated, or is a member of an
25275 explicitly instantiated class. */
25277 void
25279 {
25282 /* If this entity has already been written out, it's too late to
25283 make any modifications. */
25287 /* consteval functions are never emitted. */
25292 /* For anonymous namespace we don't need to do anything. */
25294 {
25297 }
25300 /* The TREE_PUBLIC flag for function declarations will have been
25301 set correctly by tsubst. */
25305 {
25308 }
25309 else
25310 {
25313 /* Always make artificials weak. */
25316 /* For WIN32 we also want to put explicit instantiations in
25317 linkonce sections. */
25322 /* If the function has already been instantiated, clear DECL_EXTERNAL,
25323 since start_preparsed_function wouldn't have if we had an earlier
25324 extern explicit instantiation. */
25326 }
25328 /* If EXTERN_P, then this function will not be emitted -- unless
25329 followed by an explicit instantiation, at which point its linkage
25330 will be adjusted. If !EXTERN_P, then this function will be
25331 emitted here. In neither circumstance do we want
25332 import_export_decl to adjust the linkage. */
25334 }
25336 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
25337 important template arguments. If any are missing, we check whether
25338 they're important by using error_mark_node for substituting into any
25339 args that were used for partial ordering (the ones between ARGS and END)
25340 and seeing if it bubbles up. */
25342 static bool
25344 {
25348 {
25351 }
25353 {
25357 }
25359 }
25361 /* Given two function templates PAT1 and PAT2, return:
25363 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
25364 -1 if PAT2 is more specialized than PAT1.
25365 0 if neither is more specialized.
25367 LEN indicates the number of parameters we should consider
25368 (defaulted parameters should not be considered).
25370 The 1998 std underspecified function template partial ordering, and
25371 DR214 addresses the issue. We take pairs of arguments, one from
25372 each of the templates, and deduce them against each other. One of
25373 the templates will be more specialized if all the *other*
25374 template's arguments deduce against its arguments and at least one
25375 of its arguments *does* *not* deduce against the other template's
25376 corresponding argument. Deduction is done as for class templates.
25377 The arguments used in deduction have reference and top level cv
25378 qualifiers removed. Iff both arguments were originally reference
25379 types *and* deduction succeeds in both directions, an lvalue reference
25380 wins against an rvalue reference and otherwise the template
25381 with the more cv-qualified argument wins for that pairing (if
25382 neither is more cv-qualified, they both are equal). Unlike regular
25383 deduction, after all the arguments have been deduced in this way,
25384 we do *not* verify the deduced template argument values can be
25385 substituted into non-deduced contexts.
25387 The logic can be a bit confusing here, because we look at deduce1 and
25388 targs1 to see if pat2 is at least as specialized, and vice versa; if we
25389 can find template arguments for pat1 to make arg1 look like arg2, that
25390 means that arg2 is at least as specialized as arg1. */
25392 int
25394 {
25407 /* Remove the this parameter from non-static member functions. If
25408 one is a non-static member function and the other is not a static
25409 member function, remove the first parameter from that function
25410 also. This situation occurs for operator functions where we
25411 locate both a member function (with this pointer) and non-member
25412 operator (with explicit first operand). */
25414 {
25419 }
25421 {
25424 {
25425 len--;
25427 }
25428 }
25430 /* If only one is a conversion operator, they are unordered. */
25434 /* Consider the return type for a conversion function */
25436 {
25439 len++;
25440 }
25442 processing_template_decl++;
25448 /* Stop when an ellipsis is seen. */
25450 {
25461 {
25462 /* When both arguments are pack expansions, we need only
25463 unify the patterns themselves. */
25467 /* This is the last comparison we need to do. */
25469 }
25472 {
25476 }
25479 {
25483 }
25489 {
25495 /* Setup the parameter vector, which contains only ARG1. */
25498 /* Setup the argument vector, which contains the remaining
25499 arguments. */
25508 /* We cannot deduce in the other direction, because ARG1 is
25509 a pack expansion but ARG2 is not. */
25511 }
25513 {
25519 /* Setup the parameter vector, which contains only ARG1. */
25522 /* Setup the argument vector, which contains the remaining
25523 arguments. */
25532 /* We cannot deduce in the other direction, because ARG2 is
25533 a pack expansion but ARG1 is not.*/
25535 }
25537 else
25538 {
25539 /* The normal case, where neither argument is a pack
25540 expansion. */
25547 }
25549 /* If we couldn't deduce arguments for tparms1 to make arg1 match
25550 arg2, then arg2 is not as specialized as arg1. */
25556 /* "If, for a given type, deduction succeeds in both directions
25557 (i.e., the types are identical after the transformations above)
25558 and both P and A were reference types (before being replaced with
25559 the type referred to above):
25560 - if the type from the argument template was an lvalue reference and
25561 the type from the parameter template was not, the argument type is
25562 considered to be more specialized than the other; otherwise,
25563 - if the type from the argument template is more cv-qualified
25564 than the type from the parameter template (as described above),
25565 the argument type is considered to be more specialized than the other;
25566 otherwise,
25567 - neither type is more specialized than the other." */
25570 {
25572 {
25575 else
25577 }
25579 {
25584 }
25585 }
25588 /* We've failed to deduce something in either direction.
25589 These must be unordered. */
25594 /* We have already processed all of the arguments in our
25595 handing of the pack expansion type. */
25600 }
25602 /* "In most cases, all template parameters must have values in order for
25603 deduction to succeed, but for partial ordering purposes a template
25604 parameter may remain without a value provided it is not used in the
25605 types being used for partial ordering."
25607 Thus, if we are missing any of the targs1 we need to substitute into
25608 origs1, then pat2 is not as specialized as pat1. This can happen when
25609 there is a nondeduced context. */
25615 processing_template_decl--;
25617 /* If both deductions succeed, the partial ordering selects the more
25618 constrained template. */
25619 /* P2113: If the corresponding template-parameters of the
25620 template-parameter-lists are not equivalent ([temp.over.link]) or if
25621 the function parameters that positionally correspond between the two
25622 templates are not of the same type, neither template is more
25623 specialized than the other. */
25628 {
25634 }
25636 /* All things being equal, if the next argument is a pack expansion
25637 for one function but not for the other, prefer the
25638 non-variadic function. FIXME this is bogus; see c++/41958. */
25642 {
25645 }
25651 else
25653 }
25655 /* Determine which of two partial specializations of TMPL is more
25656 specialized.
25658 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
25659 to the first partial specialization. The TREE_PURPOSE is the
25660 innermost set of template parameters for the partial
25661 specialization. PAT2 is similar, but for the second template.
25663 Return 1 if the first partial specialization is more specialized;
25664 -1 if the second is more specialized; 0 if neither is more
25665 specialized.
25667 See [temp.class.order] for information about determining which of
25668 two templates is more specialized. */
25670 static int
25672 {
25673 tree targs;
25682 /* Just like what happens for functions, if we are ordering between
25683 different template specializations, we may encounter dependent
25684 types in the arguments, and we need our dependency check functions
25685 to behave correctly. */
25689 {
25692 }
25696 {
25699 }
25702 /* If both deductions succeed, the partial ordering selects the more
25703 constrained template. */
25707 /* In the case of a tie where at least one of the templates
25708 has a parameter pack at the end, the template with the most
25709 non-packed parameters wins. */
25711 && any_deductions
25714 {
25720 /* We don't count the pack expansion at the end. */
25730 }
25733 }
25735 /* Return the template arguments that will produce the function signature
25736 DECL from the function template FN, with the explicit template
25737 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
25738 also match. Return NULL_TREE if no satisfactory arguments could be
25739 found. */
25741 static tree
25743 {
25747 tree decl_arg_types;
25750 tree arg;
25754 /* Never do unification on the 'this' parameter. */
25776 }
25778 /* Return the innermost template arguments that, when applied to a partial
25779 specialization SPEC_TMPL of TMPL, yield the ARGS.
25781 For example, suppose we have:
25783 template <class T, class U> struct S {};
25784 template <class T> struct S<T*, int> {};
25786 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
25787 partial specialization and the ARGS will be {double*, int}. The resulting
25788 vector will be {double}, indicating that `T' is bound to `double'. */
25790 static tree
25792 {
25794 tree spec_args
25797 tree deduced_args;
25798 tree innermost_deduced_args;
25802 {
25806 innermost_deduced_args);
25807 }
25808 else
25812 again:
25821 {
25823 {
25829 }
25831 }
25834 {
25837 }
25839 /* Verify that nondeduced template arguments agree with the type
25840 obtained from argument deduction.
25842 For example:
25844 struct A { typedef int X; };
25845 template <class T, class U> struct C {};
25846 template <class T> struct C<T, typename T::X> {};
25848 Then with the instantiation `C<A, int>', we can deduce that
25849 `T' is `A' but unify () does not check whether `typename T::X'
25850 is `int'. */
25861 /* We only need to check the innermost arguments; the other
25862 arguments will always agree. */
25867 /* Now that we have bindings for all of the template arguments,
25868 ensure that the arguments deduced for the template template
25869 parameters have compatible template parameter lists. See the use
25870 of template_template_parm_bindings_ok_p in fn_type_unification
25871 for more information. */
25876 }
25878 // Compare two function templates T1 and T2 by deducing bindings
25879 // from one against the other. If both deductions succeed, compare
25880 // constraints to see which is more constrained.
25881 static int
25883 {
25888 {
25891 }
25894 {
25897 }
25899 // If both deductions succeed, then one may be more constrained.
25904 }
25906 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
25907 Return the TREE_LIST node with the most specialized template, if
25908 any. If there is no most specialized template, the error_mark_node
25909 is returned.
25911 Note that this function does not look at, or modify, the
25912 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
25913 returned is one of the elements of INSTANTIATIONS, callers may
25914 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
25915 and retrieve it from the value returned. */
25917 tree
25919 {
25926 {
25932 {
25933 /* Equally specialized, move to next function. If there
25934 is no next function, nothing's most specialized. */
25939 }
25940 }
25943 /* Now verify that champ is better than everything earlier in the
25944 instantiation list. */
25947 {
25950 }
25951 }
25953 processing_template_decl--;
25959 }
25961 /* If DECL is a specialization of some template, return the most
25962 general such template. Otherwise, returns NULL_TREE.
25964 For example, given:
25966 template <class T> struct S { template <class U> void f(U); };
25968 if TMPL is `template <class U> void S<int>::f(U)' this will return
25969 the full template. This function will not trace past partial
25970 specializations, however. For example, given in addition:
25972 template <class T> struct S<T*> { template <class U> void f(U); };
25974 if TMPL is `template <class U> void S<int*>::f(U)' this will return
25975 `template <class T> template <class U> S<T*>::f(U)'. */
25977 tree
25979 {
25981 {
25984 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
25985 template friend, or a FIELD_DECL for a capture pack. */
25988 }
25990 /* Look for more and more general templates. */
25992 {
25993 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
25994 (See cp-tree.h for details.) */
26003 /* Stop if we run into an explicitly specialized class template. */
26010 }
26013 }
26015 /* Return the most specialized of the template partial specializations
26016 which can produce TARGET, a specialization of some class or variable
26017 template. The value returned is a TEMPLATE_INFO; the TI_TEMPLATE is a
26018 TEMPLATE_DECL node corresponding to the partial specialization, while
26019 the TI_ARGS is the set of template arguments that must be substituted
26020 into the template pattern in order to generate TARGET. The result is
26021 cached in the TI_PARTIAL_INFO of the corresponding TEMPLATE_INFO unless
26022 RECHECKING is true.
26024 If the choice of partial specialization is ambiguous, a diagnostic
26025 is issued, and the error_mark_node is returned. If there are no
26026 partial specializations matching TARGET, then NULL_TREE is
26027 returned, indicating that the primary template should be used. */
26029 tree
26032 {
26036 {
26041 }
26043 {
26047 }
26049 {
26054 }
26055 else
26062 && tinfo
26069 /* There are no partial specializations of this template. */
26075 /* For determining which partial specialization to use, only the
26076 innermost args are interesting. */
26079 {
26082 }
26084 /* The caller hasn't called push_to_top_level yet, but we need
26085 get_partial_spec_bindings to be done in non-template context so that we'll
26086 fully resolve everything. */
26087 processing_template_decl_sentinel ptds;
26091 {
26094 tree spec_tmpl;
26096 {
26097 /* Substitute in the template args from the enclosing class. */
26103 }
26104 else
26109 {
26113 /* Keep the candidate only if its constraints are satisfied. */
26116 }
26117 }
26125 {
26128 ;
26129 else
26130 {
26132 {
26135 {
26138 }
26139 }
26141 }
26142 }
26146 {
26149 {
26152 }
26153 }
26156 {
26163 else
26167 {
26172 }
26175 }
26181 }
26183 /* Explicitly instantiate DECL. */
26185 void
26187 {
26192 /* An error occurred, for which grokdeclarator has already issued
26193 an appropriate message. */
26196 {
26199 }
26201 {
26204 else
26207 }
26213 {
26214 /* There is an asymmetry here in the way VAR_DECLs and
26215 FUNCTION_DECLs are handled by grokdeclarator. In the case of
26216 the latter, the DECL we get back will be marked as a
26217 template instantiation, and the appropriate
26218 DECL_TEMPLATE_INFO will be set up. This does not happen for
26219 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
26220 should handle VAR_DECLs as it currently handles
26221 FUNCTION_DECLs. */
26223 {
26226 }
26229 {
26232 }
26234 {
26239 }
26240 }
26242 {
26245 }
26246 else
26249 /* Check for various error cases. Note that if the explicit
26250 instantiation is valid the RESULT will currently be marked as an
26251 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
26252 until we get here. */
26255 {
26256 /* DR 259 [temp.spec].
26258 Both an explicit instantiation and a declaration of an explicit
26259 specialization shall not appear in a program unless the explicit
26260 instantiation follows a declaration of the explicit specialization.
26262 For a given set of template parameters, if an explicit
26263 instantiation of a template appears after a declaration of an
26264 explicit specialization for that template, the explicit
26265 instantiation has no effect. */
26267 }
26269 {
26270 /* [temp.spec]
26272 No program shall explicitly instantiate any template more
26273 than once.
26275 We check DECL_NOT_REALLY_EXTERN so as not to complain when
26276 the first instantiation was `extern' and the second is not,
26277 and EXTERN_P for the opposite case. */
26280 /* If an "extern" explicit instantiation follows an ordinary
26281 explicit instantiation, the template is instantiated. */
26284 }
26286 {
26289 }
26291 {
26294 }
26297 ;
26299 {
26302 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
26305 }
26306 else
26314 }
26316 static void
26318 {
26324 {
26327 }
26328 }
26330 /* Perform an explicit instantiation of template class T. STORAGE, if
26331 non-null, is the RID for extern, inline or static. COMPLAIN is
26332 nonzero if this is called from the parser, zero if called recursively,
26333 since the standard is unclear (as detailed below). */
26335 void
26337 {
26339 {
26343 else
26346 }
26351 {
26354 t);
26356 }
26358 /* At most one of these will be true. */
26364 {
26366 {
26369 "ISO C++ 1998 forbids the use of %<extern%> on "
26371 }
26372 else
26374 "ISO C++ forbids the use of %qE"
26383 else
26385 storage);
26386 }
26389 /* DR 259 [temp.spec].
26391 Both an explicit instantiation and a declaration of an explicit
26392 specialization shall not appear in a program unless the
26393 explicit instantiation follows a declaration of the explicit
26394 specialization.
26396 For a given set of template parameters, if an explicit
26397 instantiation of a template appears after a declaration of an
26398 explicit specialization for that template, the explicit
26399 instantiation has no effect. */
26403 {
26404 /* We've already instantiated the template. */
26406 /* [temp.spec]
26408 No program shall explicitly instantiate any template more
26409 than once.
26411 If EXTERN_P then this is ok. */
26417 }
26425 /* In contrast to implicit instantiation, where only the
26426 declarations, and not the definitions, of members are
26427 instantiated, we have here:
26429 [temp.explicit]
26431 An explicit instantiation that names a class template
26432 specialization is also an explicit instantiation of the same
26433 kind (declaration or definition) of each of its members (not
26434 including members inherited from base classes and members
26435 that are templates) that has not been previously explicitly
26436 specialized in the translation unit containing the explicit
26437 instantiation, provided that the associated constraints, if
26438 any, of that member are satisfied by the template arguments
26439 of the explicit instantiation. */
26443 && !static_p
26447 {
26452 }
26454 {
26460 }
26461 }
26463 /* Given a function DECL, which is a specialization of TMPL, modify
26464 DECL to be a re-instantiation of TMPL with the same template
26465 arguments. TMPL should be the template into which tsubst'ing
26466 should occur for DECL, not the most general template.
26468 One reason for doing this is a scenario like this:
26470 template <class T>
26471 void f(const T&, int i);
26473 void g() { f(3, 7); }
26475 template <class T>
26476 void f(const T& t, const int i) { }
26478 Note that when the template is first instantiated, with
26479 instantiate_template, the resulting DECL will have no name for the
26480 first parameter, and the wrong type for the second. So, when we go
26481 to instantiate the DECL, we regenerate it. */
26483 static void
26485 {
26486 /* The arguments used to instantiate DECL, from the most general
26487 template. */
26490 /* Make sure that we can see identifiers, and compute access correctly. */
26494 {
26495 tree specs;
26499 /* Don't bother with this for unique friends that can't be redeclared and
26500 might change type if regenerated (PR69836). */
26504 /* Use the source location of the definition. */
26512 /* Instantiate a dynamic exception-specification. noexcept will be
26513 handled below. */
26516 {
26522 specs);
26523 }
26525 /* Merge parameter declarations. */
26529 {
26536 }
26539 {
26540 /* If we're regenerating a specialization, the contracts will have
26541 been copied from the most general template. Replace those with
26542 the ones from the actual specialization. */
26545 {
26548 }
26551 }
26553 /* Merge additional specifiers from the CODE_PATTERN. */
26559 }
26561 {
26570 }
26571 else
26574 done:
26576 }
26578 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
26579 substituted to get DECL. */
26581 tree
26583 {
26586 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
26587 for the instantiation. This is not always the most general
26588 template. Consider, for example:
26590 template <class T>
26591 struct S { template <class U> void f();
26592 template <> void f<int>(); };
26594 and an instantiation of S<double>::f<int>. We want TD to be the
26595 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
26597 more general template. */
26599 /* We must also deal with friend templates. Given:
26601 template <class T> struct S {
26602 template <class U> friend void f() {};
26603 };
26605 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
26606 so far as the language is concerned, but that's still
26607 where we get the pattern for the instantiation from. On
26608 other hand, if the definition comes outside the class, say:
26610 template <class T> struct S {
26611 template <class U> friend void f();
26612 };
26613 template <class U> friend void f() {}
26615 we don't need to look any further. That's what the check for
26616 DECL_INITIAL is for. */
26620 {
26621 /* The present template, TD, should not be a definition. If it
26622 were a definition, we should be using it! Note that we
26623 cannot restructure the loop to just keep going until we find
26624 a template with a definition, since that might go too far if
26625 a specialization was declared, but not defined. */
26627 /* Fetch the more general template. */
26629 }
26632 }
26634 /* Returns true if we need to instantiate this template instance even if we
26635 know we aren't going to emit it. */
26637 bool
26639 {
26640 /* We always instantiate inline functions so that we can inline them. An
26641 explicit instantiation declaration prohibits implicit instantiation of
26642 non-inline functions. With high levels of optimization, we would
26643 normally inline non-inline functions -- but we're not allowed to do
26644 that for "extern template" functions. Therefore, we check
26645 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
26649 /* And we need to instantiate static data members so that
26650 their initializers are available in integral constant
26651 expressions. */
26654 }
26656 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
26657 instantiate it now, modifying TREE_TYPE (fn). Returns false on
26658 error, true otherwise. */
26660 bool
26662 {
26666 /* Don't instantiate a noexcept-specification from template context. */
26676 {
26678 /* We're in start_preparsed_function, keep going. */
26685 }
26696 /* For a member friend template we can get a TEMPLATE_DECL. Let's use
26697 its FUNCTION_DECL for the rest of this function -- push_access_scope
26698 doesn't accept TEMPLATE_DECLs. */
26700 {
26703 }
26706 {
26711 }
26713 {
26717 {
26720 /* This might have failed because of an unparsed DMI, so
26721 let's try again later. */
26723 }
26725 {
26726 /* If hash_set::add returns true, the element was already there. */
26731 fn);
26733 }
26735 {
26743 {
26744 /* If needed, set current_class_ptr for the benefit of
26745 tsubst_copy/PARM_DECL. */
26750 }
26752 /* If this function is represented by a TEMPLATE_DECL, then
26753 the deferred noexcept-specification might still contain
26754 dependent types, even after substitution. And we need the
26755 dependency check functions to work in build_noexcept_spec. */
26759 /* Do deferred instantiation of the noexcept-specifier. */
26764 /* Build up the noexcept-specification. */
26774 }
26775 else
26780 }
26783 {
26784 /* This failed with a hard error, so let's go with false. */
26787 }
26794 }
26796 /* We're starting to process the function INST, an instantiation of PATTERN;
26797 add their parameters to local_specializations. */
26799 void
26801 {
26805 {
26809 }
26811 {
26813 {
26816 }
26817 else
26818 {
26819 /* Register the (value) argument pack as a specialization of
26820 TMPL_PARM, then move on. */
26823 }
26824 }
26826 }
26828 /* Instantiate the body of D using PATTERN with ARGS. We have
26829 already determined PATTERN is the correct template to use.
26830 NESTED_P is true if this is a nested function, in which case
26831 PATTERN will be a FUNCTION_DECL not a TEMPLATE_DECL. */
26833 static void
26835 {
26840 {
26843 }
26844 else
26845 /* Only OMP reductions are nested. */
26857 {
26858 /* The variable might be a lambda's extra scope, and that
26859 lambda's visibility depends on D's. */
26862 }
26864 /* Mark D as instantiated so that recursive calls to
26865 instantiate_decl do not try to instantiate it again. */
26869 /* Regenerate the declaration in case the template has been modified
26870 by a subsequent redeclaration. */
26873 /* We already set the file and line above. Reset them now in case
26874 they changed as a result of calling regenerate_decl_from_template. */
26878 {
26879 /* Clear out DECL_RTL; whatever was there before may not be right
26880 since we've reset the type of the declaration. */
26884 /* The initializer is placed in DECL_INITIAL by
26885 regenerate_decl_from_template so we don't need to
26886 push/pop_access_scope again here. Pull it out so that
26887 cp_finish_decl can process it. */
26893 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
26894 initializer. That function will defer actual emission until
26895 we have a chance to determine linkage. */
26898 /* Enter the scope of D so that access-checking works correctly. */
26908 }
26912 {
26913 /* Set up the list of local specializations. */
26917 /* Set up context. */
26920 else
26921 {
26925 }
26927 /* Create substitution entries for the parameters. */
26930 /* Substitute into the body of the function. */
26934 else
26935 {
26939 /* Set the current input_location to the end of the function
26940 so that finish_function knows where we are. */
26941 input_location
26944 /* Remember if we saw an infinite loop in the template. */
26945 current_function_infinite_loop
26947 }
26949 /* Finish the function. */
26952 else
26953 {
26956 }
26960 }
26962 /* We're not deferring instantiation any more. */
26970 }
26972 /* Produce the definition of D, a _DECL generated from a template. If
26973 DEFER_OK is true, then we don't have to actually do the
26974 instantiation now; we just have to do it sometime. Normally it is
26975 an error if this is an explicit instantiation but D is undefined.
26976 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
26977 instantiated class template. */
26979 tree
26981 {
26983 tree gen_args;
26984 tree args;
26985 tree td;
26986 tree code_pattern;
26987 tree spec;
26988 tree gen_tmpl;
26996 /* This function should only be used to instantiate templates for
26997 functions and static member variables. */
27000 /* A concept is never instantiated. */
27006 /* We may have a pending instantiation of D itself. */
27009 /* Variables are never deferred; if instantiation is required, they
27010 are instantiated right away. That allows for better code in the
27011 case that an expression refers to the value of the variable --
27012 if the variable has a constant value the referring expression can
27013 take advantage of that fact. */
27017 /* Don't instantiate cloned functions. Instead, instantiate the
27018 functions they cloned. */
27027 /* D has already been instantiated or explicitly specialized, so
27028 there's nothing for us to do here.
27030 It might seem reasonable to check whether or not D is an explicit
27031 instantiation, and, if so, stop here. But when an explicit
27032 instantiation is deferred until the end of the compilation,
27033 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
27034 the instantiation. */
27037 /* Check to see whether we know that this template will be
27038 instantiated in some other file, as with "extern template"
27039 extension. */
27042 /* In general, we do not instantiate such templates. */
27049 /* We should already have the extra args. */
27053 /* And what's in the hash table should match D. */
27055 == d
27058 /* This needs to happen before any tsubsting. */
27064 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
27065 for the instantiation. */
27070 {
27071 /* Look up an explicit specialization, if any. */
27074 {
27077 }
27078 }
27082 /* We should never be trying to instantiate a member of a class
27083 template or partial specialization. */
27088 /* In the case of a friend template whose definition is provided
27089 outside the class, we may have too many arguments. Drop the
27090 ones we don't need. The same is true for specializations. */
27091 args = get_innermost_template_args
27095 {
27101 }
27102 else
27103 {
27107 else
27109 }
27111 /* We may be in the middle of deferred access check. Disable it now. */
27114 /* Unless an explicit instantiation directive has already determined
27115 the linkage of D, remember that a definition is available for
27116 this entity. */
27126 /* If D is a member of an explicitly instantiated class template,
27127 and no definition is available, treat it like an implicit
27128 instantiation. */
27131 {
27132 /* Leave linkage flags alone on instantiations with anonymous
27133 visibility. */
27135 {
27138 }
27140 }
27142 /* Defer all other templates, unless we have been explicitly
27143 forbidden from doing so. */
27145 template. */
27146 ! pattern_defined
27147 /* If it's OK to postpone instantiation, do so. */
27148 || defer_ok
27149 /* If this is a static data member that will be defined
27150 elsewhere, we don't want to instantiate the entire data
27151 member, but we do want to instantiate the initializer so that
27152 we can substitute that elsewhere. */
27154 /* Handle here a deleted function too, avoid generating
27155 its body (c++/61080). */
27157 {
27158 /* The definition of the static data member is now required so
27159 we must substitute the initializer. */
27163 {
27164 tree ns;
27165 tree init;
27174 args,
27176 /* If instantiating the initializer involved instantiating this
27177 again, don't call cp_finish_decl twice. */
27179 {
27180 /* Make sure the initializer is still constant, in case of
27181 circular dependency (template/instantiate6.C). */
27182 const_init
27186 }
27190 }
27192 /* We restore the source position here because it's used by
27193 add_pending_template. */
27199 /* [temp.explicit]
27201 The definition of a non-exported function template, a
27202 non-exported member function template, or a non-exported
27203 member function or static data member of a class template
27204 shall be present in every translation unit in which it is
27205 explicitly instantiated. */
27209 /* If we're in unevaluated context, we just wanted to get the
27210 constant value; this isn't an odr use, so don't queue
27211 a full instantiation. */
27213 /* ??? Historically, we have instantiated inline functions, even
27214 when marked as "extern template". */
27217 }
27218 else
27219 {
27224 }
27233 }
27235 /* Run through the list of templates that we wish we could
27236 instantiate, and instantiate any we can. RETRIES is the
27237 number of times we retry pending template instantiation. */
27239 void
27241 {
27245 /* Instantiating templates may trigger vtable generation. This in turn
27246 may require further template instantiations. We place a limit here
27247 to avoid infinite loop. */
27249 {
27253 "template instantiation depth exceeds maximum of %d"
27254 " instantiating %q+D, possibly from virtual table generation"
27258 /* Pretend that we defined it. */
27261 }
27263 do
27264 {
27269 {
27274 {
27276 {
27291 }
27294 }
27295 else
27296 {
27299 {
27300 instantiation
27306 }
27310 }
27313 {
27314 /* If INSTANTIATION has been instantiated, then we don't
27315 need to consider it again in the future. */
27320 }
27321 else
27322 {
27325 }
27328 }
27330 }
27334 }
27336 /* Substitute ARGVEC into T, which is a list of initializers for
27337 either base class or a non-static data member. The TREE_PURPOSEs
27338 are DECLs, and the TREE_VALUEs are the initializer values. Used by
27339 instantiate_decl. */
27341 static tree
27343 {
27348 {
27349 tree decl;
27350 tree init;
27356 {
27357 tree expr;
27358 tree arg;
27360 /* Expand the base class expansion type into separate base
27361 classes. */
27363 tf_warning_or_error,
27364 NULL_TREE);
27368 /* We'll be building separate TREE_LISTs of arguments for
27369 each base. */
27375 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
27376 expand each argument in the TREE_VALUE of t. */
27383 /* VOID_TYPE_NODE is used to indicate
27384 value-initialization. */
27385 {
27388 }
27389 else
27390 {
27391 /* Substitute parameter packs into each argument in the
27392 TREE_LIST. */
27395 {
27396 tree expanded_exprs;
27398 /* Expand the argument. */
27399 tree value;
27402 else
27403 {
27406 }
27407 expanded_exprs
27409 tf_warning_or_error,
27410 NULL_TREE);
27414 /* Prepend each of the expanded expressions to the
27415 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
27423 else
27428 }
27431 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
27432 since we built them backwards. */
27434 {
27437 }
27438 }
27439 }
27442 {
27444 {
27448 }
27449 else
27450 {
27451 tree tmp;
27465 /* If we had an initializer but it instantiated to nothing,
27466 value-initialize the object. This will only occur when
27467 the initializer was a pack expansion where the parameter
27468 packs used in that expansion were of length zero. */
27471 }
27475 {
27477 decl);
27479 }
27480 /* Look for a target constructor. */
27484 {
27487 {
27491 }
27493 }
27496 {
27498 /* Carry over the dummy TREE_TYPE node containing the source
27499 location. */
27503 }
27504 }
27505 }
27507 }
27509 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
27510 is the instantiation (which should have been created with
27511 start_enum) and ARGS are the template arguments to use. */
27513 static void
27515 {
27516 tree e;
27522 {
27523 tree value;
27526 /* Note that in a template enum, the TREE_VALUE is the
27527 CONST_DECL, not the corresponding INTEGER_CST. */
27531 /* Give this enumeration constant the correct access. */
27534 /* Actually build the enumerator itself. Here we're assuming that
27535 enumerators can't have dependent attributes. */
27539 /* Attribute deprecated without an argument isn't sticky: it'll
27540 melt into a tree flag, so we need to propagate the flag here,
27541 since we just created a new enumerator. */
27544 }
27556 }
27558 /* DECL is a FUNCTION_DECL that is a template specialization. Return
27559 its type -- but without substituting the innermost set of template
27560 arguments. So, innermost set of template parameters will appear in
27561 the type. */
27563 tree
27565 {
27566 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
27568 }
27570 /* Return truthvalue if we're processing a template different from
27571 the last one involved in diagnostics. */
27572 bool
27574 {
27576 }
27578 /* Remember current template involved in diagnostics. */
27579 void
27581 {
27583 }
27587 {
27589 }
27591 /* Return TRUE if current_function_decl is being instantiated, false
27592 otherwise. */
27594 bool
27596 {
27600 }
27602 /* [temp.param] Check that template non-type parm TYPE is of an allowable
27603 type. Return false for ok, true for disallowed. Issue error and
27604 inform messages under control of COMPLAIN. */
27606 static bool
27608 {
27619 {
27621 {
27626 }
27628 }
27633 /* Fall through; before C++11 alias templates, a bound ttp
27636 /* Any other wildcard type not already handled above is allowed. */
27643 {
27651 {
27652 auto_diagnostic_group d;
27656 }
27658 }
27660 {
27665 }
27668 {
27671 else
27673 type);
27674 }
27676 }
27678 /* Returns true iff the noexcept-specifier for TYPE is value-dependent. */
27680 static bool
27682 {
27685 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
27686 affect overload resolution and treating it as dependent breaks
27687 things. Same for an unparsed noexcept expression. */
27694 }
27696 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
27697 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
27699 static bool
27701 {
27702 tree scope;
27704 /* [temp.dep.type]
27706 A type is dependent if it is:
27708 -- a template parameter. Template template parameters are types
27709 for us (since TYPE_P holds true for them) so we handle
27710 them here. */
27714 /* -- a qualified-id with a nested-name-specifier which contains a
27715 class-name that names a dependent type or whose unqualified-id
27716 names a dependent type. */
27720 /* An alias template specialization can be dependent even if the
27721 resulting type is not. */
27725 /* -- a cv-qualified type where the cv-unqualified type is
27726 dependent.
27727 No code is necessary for this bullet; the code below handles
27728 cv-qualified types, and we don't want to strip aliases with
27729 TYPE_MAIN_VARIANT because of DR 1558. */
27730 /* -- a compound type constructed from any dependent type. */
27738 {
27739 tree arg_type;
27744 arg_type;
27750 /* A value-dependent noexcept-specifier makes the type dependent. */
27753 }
27754 /* -- an array type constructed from any dependent type or whose
27755 size is specified by a constant expression that is
27756 value-dependent.
27758 We checked for type- and value-dependence of the bounds in
27759 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
27761 {
27766 }
27768 /* -- a template-id in which either the template name is a template
27769 parameter ... */
27772 /* ... or any of the template arguments is a dependent type or
27773 an expression that is type-dependent or value-dependent. */
27775 && (any_dependent_template_arguments_p
27779 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and TRAIT_TYPEs are
27780 dependent; if the argument of the `typeof' expression is not
27781 type-dependent, then it should already been have resolved. */
27787 /* A template argument pack is dependent if any of its packed
27788 arguments are. */
27790 {
27795 }
27797 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
27798 be template parameters. */
27808 /* The standard does not specifically mention types that are local
27809 to template functions or local classes, but they should be
27810 considered dependent too. For example:
27812 template <int I> void f() {
27813 enum E { a = I };
27814 S<sizeof (E)> s;
27815 }
27817 The size of `E' cannot be known until the value of `I' has been
27818 determined. Therefore, `E' must be considered dependent. */
27822 /* Don't use type_dependent_expression_p here, as it can lead
27823 to infinite recursion trying to determine whether a lambda
27824 nested in a lambda is dependent (c++/47687). */
27828 && (any_dependent_template_arguments_p
27832 /* Other types are non-dependent. */
27834 }
27836 /* Returns TRUE if TYPE is dependent, in the sense of
27837 [temp.dep.type]. Note that a NULL type is considered dependent. */
27839 bool
27841 {
27842 /* If there are no template parameters in scope, then there can't be
27843 any dependent types. */
27845 {
27846 /* If we are not processing a template, then nobody should be
27847 providing us with a dependent type. */
27851 }
27853 /* If the type is NULL, we have not computed a type for the entity
27854 in question; in that case, the type is dependent. */
27858 /* Erroneous types can be considered non-dependent. */
27862 /* If we have not already computed the appropriate value for TYPE,
27863 do so now. */
27865 {
27868 }
27871 }
27873 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
27874 lookup. In other words, a dependent type that is not the current
27875 instantiation. */
27877 bool
27879 {
27882 }
27884 /* True if we might find more declarations in SCOPE during instantiation than
27885 we can when parsing the template. */
27887 bool
27889 {
27891 }
27893 /* T is a SCOPE_REF. Return whether it represents a non-static member of
27894 an unknown base of 'this' (and is therefore instantiation-dependent). */
27896 static bool
27898 {
27915 }
27917 /* T is a SCOPE_REF; return whether we need to consider it
27918 instantiation-dependent so that we can check access at instantiation
27919 time even though we know which member it resolves to. */
27921 static bool
27923 {
27931 else
27933 }
27935 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
27936 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
27937 expression. */
27939 /* Note that this predicate is not appropriate for general expressions;
27940 only constant expressions (that satisfy potential_constant_expression)
27941 can be tested for value dependence. */
27943 bool
27945 {
27949 /* A type-dependent expression is also value-dependent. */
27954 {
27956 /* A dependent member function of the current instantiation. */
27960 /* A dependent member function of the current instantiation. */
27967 /* A name that has not been looked up -- must be dependent. */
27971 /* A non-type template parm. */
27975 /* A non-type template parm. */
27981 /* A constant with literal type and is initialized
27982 with an expression that is value-dependent. */
27986 {
27989 /* __PRETTY_FUNCTION__ inside a template function is dependent
27990 on the name of the function. */
27992 /* It might be used in a template, but not a template
27993 function, in which case its DECL_VALUE_EXPR will be
27994 "top level". */
27997 }
27999 /* FIXME cp_finish_decl doesn't fold reference initializers. */
28001 /* We have a constexpr variable and we're processing a template. When
28002 there's lifetime extension involved (for which finish_compound_literal
28003 used to create a temporary), we'll not be able to evaluate the
28004 variable until instantiating, so pretend it's value-dependent. */
28016 /* These expressions are value-dependent if the type to which
28017 the cast occurs is dependent or the expression being casted
28018 is value-dependent. */
28019 {
28025 /* A functional cast has a list of operands. */
28028 {
28029 /* If there are no operands, it must be an expression such
28030 as "int()". This should not happen for aggregate types
28031 because it would form non-constant expressions. */
28036 }
28046 }
28051 /* FALLTHRU */
28054 /* A `sizeof' expression is value-dependent if the operand is
28055 type-dependent or is a pack expansion. */
28064 /* An 'encode' expression is value-dependent if the operand is
28065 type-dependent. */
28074 /* All instantiation-dependent expressions should also be considered
28075 value-dependent. */
28083 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
28084 is value-dependent. */
28091 {
28107 }
28118 {
28122 }
28125 /* Treat all requires-expressions as value-dependent so
28126 we don't try to fold them. */
28133 {
28140 {
28142 /* In a call to a constexpr member function, look through the
28143 implicit ADDR_EXPR on the object argument so that it doesn't
28144 cause the call to be considered value-dependent. We also
28145 look through it in potential_constant_expression. */
28152 }
28154 }
28161 {
28163 tree val;
28170 }
28173 /* Treat a GNU statement expression as dependent to avoid crashing
28174 under instantiate_non_dependent_expr; it can't be constant. */
28179 /* The second operand is a type, which type_dependent_expression_p
28180 (and therefore value_dependent_expression_p) doesn't want to see. */
28186 /* A constant expression is value-dependent if any subexpression is
28187 value-dependent. */
28189 {
28196 {
28200 {
28203 /* In some cases, some of the operands may be missing.
28204 (For example, in the case of PREDECREMENT_EXPR, the
28205 amount to increment by may be missing.) That doesn't
28206 make the expression dependent. */
28209 }
28210 }
28214 }
28216 }
28218 /* The expression is not value-dependent. */
28220 }
28222 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
28223 [temp.dep.expr]. Note that an expression with no type is
28224 considered dependent. Other parts of the compiler arrange for an
28225 expression with type-dependent subexpressions to have no type, so
28226 this function doesn't have to be fully recursive. */
28228 bool
28230 {
28241 /* An unresolved name is always dependent. */
28247 /* A lambda-expression in template context is dependent. dependent_type_p is
28248 true for a lambda in the scope of a class or function template, but that
28249 doesn't cover all template contexts, like a default template argument. */
28253 /* A fold expression is type-dependent. */
28260 /* Some expression forms are never type-dependent. */
28273 /* The types of these expressions depends only on the type to which
28274 the cast occurs. */
28283 /* The types of these expressions depends only on the type created
28284 by the expression. */
28287 {
28288 /* For NEW_EXPR tree nodes created inside a template, either
28289 the object type itself or a TREE_LIST may appear as the
28290 operand 1. */
28293 /* This is an array type. We need to check array dimensions
28294 as well. */
28296 || value_dependent_expression_p
28298 /* Array type whose dimension has to be deduced. */
28302 else
28304 }
28307 {
28311 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
28312 contains an identifier associated by name lookup with one or more
28313 declarations declared with a dependent type, or...a
28314 nested-name-specifier or qualified-id that names a member of an
28315 unknown specialization. */
28318 }
28328 {
28333 }
28335 /* A static data member of the current instantiation with incomplete
28336 array type is type-dependent, as the definition and specializations
28337 can have different bounds. */
28344 /* An array of unknown bound depending on a variadic parameter, eg:
28346 template<typename... Args>
28347 void foo (Args... args)
28348 {
28349 int arr[] = { args... };
28350 }
28352 template<int... vals>
28353 void bar ()
28354 {
28355 int arr[] = { vals... };
28356 }
28358 If the array has no length and has an initializer, it must be that
28359 we couldn't determine its length in cp_complete_array_type because
28360 it is dependent. */
28368 /* Pull a FUNCTION_DECL out of a BASELINK if we can. */
28370 {
28375 }
28377 /* A function or variable template-id is type-dependent if it has any
28378 dependent template arguments. */
28382 {
28383 /* Consider the innermost template arguments, since those are the ones
28384 that come from the template-id; the template arguments for the
28385 enclosing class do not make it type-dependent unless they are used in
28386 the type of the decl. */
28388 && (any_dependent_template_arguments_p
28391 }
28393 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
28394 type-dependent. Checking this is important for functions with auto return
28395 type, which looks like a dependent type. */
28404 {
28408 }
28410 /* Otherwise, its constraints could still depend on outer template parameters
28411 from its (dependent) scope. */
28413 /* As an optimization, check this cheaper sufficient condition first.
28414 (At this point we've established that we're looking at a member of
28415 a dependent class, so it makes sense to start treating say undeduced
28416 auto as dependent.) */
28421 /* Always dependent, on the number of arguments if nothing else. */
28426 {
28431 {
28437 }
28438 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
28442 /* CO_AWAIT/YIELD_EXPR with unknown type is always dependent. */
28448 {
28453 }
28456 {
28463 }
28472 }
28474 /* The type of a non-type template parm declared with a placeholder type
28475 depends on the corresponding template argument, even though
28476 placeholders are not normally considered dependent. */
28483 /* Dependent type attributes might not have made it from the decl to
28484 the type yet. */
28490 }
28492 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
28493 type-dependent if the expression refers to a member of the current
28494 instantiation and the type of the referenced member is dependent, or the
28495 class member access expression refers to a member of an unknown
28496 specialization.
28498 This function returns true if the OBJECT in such a class member access
28499 expression is of an unknown specialization. */
28501 bool
28503 {
28504 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
28505 dependent. */
28510 }
28512 /* walk_tree callback function for instantiation_dependent_expression_p,
28513 below. Returns non-zero if a dependent subexpression is found. */
28515 static tree
28518 {
28520 {
28521 /* We don't have to worry about decltype currently because decltype
28522 of an instantiation-dependent expr is a dependent type. This
28523 might change depending on the resolution of DR 1172. */
28526 }
28529 {
28530 /* Don't treat an argument list as dependent just because it has no
28531 TREE_TYPE. */
28542 /* We'll check value-dependence separately. */
28545 /* Handle expressions with type operands. */
28550 {
28555 {
28558 else
28559 {
28562 }
28563 }
28565 }
28569 /* In a template, finish_class_member_access_expr creates a
28570 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
28571 type-dependent, so that we can check access control at
28572 instantiation time (PR 42277). See also Core issue 1273. */
28579 else
28582 /* Treat statement-expressions as dependent. */
28586 /* Treat requires-expressions as dependent. */
28597 /* Before C++17, a noexcept-specifier isn't part of the function type
28598 so it doesn't affect type dependence, but we still want to consider it
28599 for instantiation dependence. */
28608 }
28612 else
28614 }
28616 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
28617 sense defined by the ABI:
28619 "An expression is instantiation-dependent if it is type-dependent
28620 or value-dependent, or it has a subexpression that is type-dependent
28621 or value-dependent."
28623 Except don't actually check value-dependence for unevaluated expressions,
28624 because in sizeof(i) we don't care about the value of i. Checking
28625 type-dependence will in turn check value-dependence of array bounds/template
28626 arguments as needed. */
28628 bool
28630 {
28631 tree result;
28642 }
28644 /* As above, but also check value-dependence of the expression as a whole. */
28646 bool
28648 {
28650 || (processing_template_decl
28653 }
28655 /* Like type_dependent_expression_p, but it also works while not processing
28656 a template definition, i.e. during substitution or mangling. */
28658 bool
28660 {
28666 }
28668 /* Returns TRUE if ARGS contains a type-dependent expression. */
28670 bool
28672 {
28681 }
28683 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
28684 expressions) contains any type-dependent expressions. */
28686 bool
28688 {
28694 }
28696 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
28697 expressions) contains any value-dependent expressions. */
28699 bool
28701 {
28707 }
28709 /* Returns TRUE if the ARG (a template argument) is dependent. */
28711 bool
28713 {
28717 /* Assume a template argument that was wrongly written by the user
28718 is dependent. This is consistent with what
28719 any_dependent_template_arguments_p [that calls this function]
28720 does. */
28730 {
28733 /* A member template of a dependent class is not necessarily
28734 type-dependent, but it is a dependent template argument because it
28735 will be a member of an unknown specialization to that template. */
28738 }
28740 {
28746 }
28749 else
28751 }
28753 /* Identify any expressions that use function parms. */
28755 static tree
28757 {
28760 {
28763 }
28765 }
28767 /* Returns true if a type specialization formed using the template
28768 arguments ARGS needs to use structural equality. */
28770 bool
28772 {
28782 {
28785 {
28791 {
28792 /* Look inside the argument pack. */
28795 }
28798 {
28807 /* An any_targ_node argument (added by add_defaults_to_ttp)
28808 makes the corresponding specialization not canonicalizable,
28809 since template_args_equal always return true for it. We
28810 may see this when called from bind_template_template_parm. */
28812 /* Checking current_function_decl because this structural
28813 comparison is only necessary for redeclaration. */
28816 && (cp_walk_tree_without_duplicates
28818 /* The identity of a class template specialization that uses
28819 a function parameter depends on the identity of the function.
28820 And if this specialization appeared in the trailing return
28821 type thereof, we don't know the identity of the function
28822 (e.g. if it's a redeclaration or a new function) until we
28823 form its signature and go through duplicate_decls. Thus
28824 it's unsafe to decide on a canonical type now (which depends
28825 on the DECL_CONTEXT of the function parameter, which can get
28826 mutated after the fact by duplicate_decls), so just require
28827 structural equality in this case (PR52830). */
28829 }
28830 }
28831 }
28834 }
28836 /* Returns true if ARGS (a collection of template arguments) contains
28837 any dependent arguments. */
28839 bool
28841 {
28848 {
28853 }
28856 }
28858 /* Returns true if ARGS contains any errors. */
28860 bool
28862 {
28870 {
28873 else
28875 }
28881 {
28886 }
28889 }
28891 /* Returns TRUE if the template TMPL is type-dependent. */
28893 bool
28895 {
28897 {
28902 }
28904 /* Template template parameters are dependent. */
28908 /* So are names that have not been looked up. */
28912 }
28914 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
28916 bool
28918 {
28921 }
28923 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
28924 are dependent. */
28926 bool
28928 {
28935 {
28960 {
28964 }
28968 {
28972 {
28978 /* If this loop has a class iterator with != comparison
28979 with increment other than i++/++i/i--/--i, make sure the
28980 increment is constant. */
28983 {
28986 else
28990 }
28991 }
28992 }
28993 }
28996 }
28998 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
28999 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
29000 no such TYPE can be found. Note that this function peers inside
29001 uninstantiated templates and therefore should be used only in
29002 extremely limited situations. ONLY_CURRENT_P restricts this
29003 peering to the currently open classes hierarchy (which is required
29004 when comparing types). */
29006 tree
29008 {
29009 tree scope;
29010 tree name;
29011 tree decl;
29013 tree pushed_scope;
29014 tree result;
29019 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
29022 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
29023 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of a
29024 TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL
29025 representing the typedef. In that case TYPE_IDENTIFIER (type) is
29026 not the non-qualified identifier of the TYPENAME_TYPE anymore.
29027 So by getting the TYPE_IDENTIFIER of the _main declaration_ of
29028 the TYPENAME_TYPE instead, we avoid messing up with a possible
29029 typedef variant case. */
29032 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
29033 it first before we can figure out what NAME refers to. */
29035 {
29037 /* Given a class template A with a dependent base with nested type C,
29038 typedef typename A::C::C C will land us here, as trying to resolve
29039 the initial A::C leads to the local C typedef, which leads back to
29040 A::C::C. So we break the recursion now. */
29042 else
29044 }
29045 /* If we don't know what SCOPE refers to, then we cannot resolve the
29046 TYPENAME_TYPE. */
29049 /* If this is a typedef, we don't want to look inside (c++/11987). */
29052 /* If SCOPE isn't the template itself, it will not have a valid
29053 TYPE_FIELDS list. */
29055 /* scope is either the template itself or a compatible instantiation
29056 like X<T>, so look up the name in the original template. */
29058 /* If scope has no fields, it can't be a current instantiation. Check this
29059 before currently_open_class to avoid infinite recursion (71515). */
29062 /* If the SCOPE is not the current instantiation, there's no reason
29063 to look inside it. */
29066 /* Enter the SCOPE so that name lookup will be resolved as if we
29067 were in the class definition. In particular, SCOPE will no
29068 longer be considered a dependent type. */
29070 /* Look up the declaration. */
29072 tf_warning_or_error);
29076 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
29077 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
29083 {
29087 }
29090 {
29091 /* Obtain the template and the arguments. */
29094 {
29095 /* We get here with a plain identifier because a previous tentative
29096 parse of the nested-name-specifier as part of a ptr-operator saw
29097 ::template X<A>. The use of ::template is necessary in a
29098 ptr-operator, but wrong in a declarator-id.
29100 [temp.names]: In a qualified-id of a declarator-id, the keyword
29101 template shall not appear at the top level. */
29105 }
29107 /* Instantiate the template. */
29113 }
29115 /* Leave the SCOPE. */
29119 /* If we failed to resolve it, return the original typename. */
29123 /* If lookup found a typename type, resolve that too. */
29125 {
29126 /* Ill-formed programs can cause infinite recursion here, so we
29127 must catch that. */
29131 }
29133 /* Qualify the resulting type. */
29139 }
29141 /* EXPR is an expression which is not type-dependent. Return a proxy
29142 for EXPR that can be used to compute the types of larger
29143 expressions containing EXPR. */
29145 tree
29147 {
29149 tree inner_expr;
29151 /* When checking, try to get a constant value for all non-dependent
29152 expressions in order to expose bugs in *_dependent_expression_p
29153 and constexpr. This can affect code generation, see PR70704, so
29154 only do this for -fchecking=2. */
29157 /* Don't do this during nsdmi parsing as it can lead to
29158 unexpected recursive instantiations. */
29160 /* Don't do this during concept processing either and for
29161 the same reason. */
29167 /* Preserve OVERLOADs; the functions must be available to resolve
29168 types. */
29179 /* There is no need to return a proxy for a variable, parameter
29180 or enumerator. */
29184 /* Preserve string constants; conversions from string constants to
29185 "char *" are allowed, even though normally a "const char *"
29186 cannot be used to initialize a "char *". */
29189 /* Preserve void and arithmetic constants, as an optimization -- there is no
29190 reason to create a new node. */
29195 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
29196 There is at least one place where we want to know that a
29197 particular expression is a throw-expression: when checking a ?:
29198 expression, there are special rules if the second or third
29199 argument is a throw-expression. */
29203 /* Don't wrap an initializer list, we need to be able to look inside. */
29207 /* Don't wrap a dummy object, we need to be able to test for it. */
29225 /* If the type is unknown, it can't really be non-dependent */
29228 /* Otherwise, build a NON_DEPENDENT_EXPR. */
29231 }
29233 /* ARGS is a vector of expressions as arguments to a function call.
29234 Replace the arguments with equivalent non-dependent expressions.
29235 This modifies ARGS in place. */
29237 void
29239 {
29241 tree arg;
29244 {
29248 }
29249 }
29251 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
29252 TEMPLATE_TYPE_PARM with a level one deeper than the actual template parms,
29253 by default. If set_canonical is true, we set TYPE_CANONICAL on it. */
29255 static tree
29257 {
29273 }
29275 tree
29277 {
29279 }
29281 tree
29283 {
29285 }
29287 /* Return a C++17 deduction placeholder for class template TMPL.
29288 There are represented as an 'auto' with the special level 0 and
29289 CLASS_PLACEHOLDER_TEMPLATE set. */
29291 tree
29293 {
29296 /* Our canonical type depends on the placeholder. */
29299 }
29301 /* True iff T is a C++17 class template deduction placeholder. */
29303 bool
29305 {
29307 }
29309 /* Make a "constrained auto" type-specifier. This is an auto or
29310 decltype(auto) type with constraints that must be associated after
29311 deduction. The constraint is formed from the given concept CON
29312 and its optional sequence of template arguments ARGS.
29314 TYPE must be the result of make_auto_type or make_decltype_auto_type. */
29316 static tree
29318 {
29319 /* Build the constraint. */
29331 /* Our canonical type depends on the constraint. */
29334 /* Attach the constraint to the type declaration. */
29336 }
29338 /* Make a "constrained auto" type-specifier. */
29340 tree
29342 {
29345 }
29347 /* Make a "constrained decltype(auto)" type-specifier. */
29349 tree
29351 {
29354 }
29356 /* Returns true if the placeholder type constraint T has any dependent
29357 (explicit) template arguments. */
29359 static bool
29361 {
29366 {
29369 }
29376 }
29378 /* Build and return a concept definition. Like other templates, the
29379 CONCEPT_DECL node is wrapped by a TEMPLATE_DECL. This returns the
29380 the TEMPLATE_DECL. */
29382 tree
29384 {
29390 /* A concept-definition shall not have associated constraints. */
29392 {
29395 }
29397 /* A concept-definition shall appear in namespace scope. Templates
29398 aren't allowed in block scope, so we only need to check for class
29399 scope. */
29401 {
29404 }
29407 {
29410 }
29412 /* Initially build the concept declaration; its type is bool. */
29422 /* Push the enclosing template. */
29424 }
29426 /* Given type ARG, return std::initializer_list<ARG>. */
29428 static tree
29430 {
29435 {
29439 "deducing from brace-enclosed initializer list"
29443 }
29449 }
29451 /* Replace auto in TYPE with std::initializer_list<auto>. */
29453 static tree
29455 {
29462 }
29464 /* Hash traits for hashing possibly constrained 'auto'
29465 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
29468 {
29471 };
29473 /* Hash the 'auto' T. */
29475 inline hashval_t
29477 {
29479 /* Matching constrained-type-specifiers denote the same template
29480 parameter, so hash the constraint. */
29482 else
29483 /* But unconstrained autos are all separate, so just hash the pointer. */
29485 }
29487 /* Compare two 'auto's. */
29491 {
29498 /* Two unconstrained autos are distinct. */
29503 }
29505 /* for_each_template_parm callback for extract_autos: if t is a (possibly
29506 constrained) auto, add it to the vector. */
29508 static int
29510 {
29513 {
29514 /* All the autos were built with index 0; fix that up now. */
29518 /* If this is a repeated constrained-type-specifier, use the index we
29519 chose before. */
29521 else
29522 {
29523 /* Otherwise this is new, so use the current count. */
29526 }
29528 {
29533 }
29534 }
29536 /* Always keep walking. */
29538 }
29540 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
29541 says they can appear anywhere in the type. */
29543 static tree
29545 {
29553 {
29557 }
29560 }
29562 /* The stem for deduction guide names. */
29565 /* Return the name for a deduction guide for class template TMPL. */
29567 tree
29569 {
29580 }
29582 /* True if NAME is the name of a deduction guide. */
29584 bool
29586 {
29590 }
29592 /* True if FN is a deduction guide. */
29594 bool
29596 {
29601 }
29603 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
29605 bool
29607 {
29614 }
29616 /* True if FN is a guide generated from a constructor template. */
29618 bool
29620 {
29628 }
29630 /* True if FN is an aggregate initialization guide or the copy deduction
29631 guide. */
29633 bool
29635 {
29639 /* Explicitly declared. */
29642 /* Derived from a constructor. */
29645 }
29647 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
29648 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
29649 template parameter types. Note that the handling of template template
29650 parameters relies on current_template_parms being set appropriately for the
29651 new template. */
29653 static tree
29656 {
29662 tree newtype;
29665 {
29669 }
29670 else
29671 {
29674 {
29675 // Substitute once to fix references to other template parameters.
29678 // Now substitute again to reduce the level of the auto.
29681 }
29682 else
29685 }
29687 tree newdecl
29692 tree newidx;
29695 {
29704 {
29709 // First create a copy (ttargs) of tsubst_args with an
29710 // additional level for the template template parameter's own
29711 // template parameters (ttparms).
29712 tree ttparms = (INNERMOST_TEMPLATE_PARMS
29720 // Substitute ttargs into ttparms to fix references to
29721 // other template parameters.
29724 // Now substitute again with args based on tparms, to reduce
29725 // the level of the ttparms.
29728 complain);
29729 // Finally, tack the adjusted parms onto tparms.
29732 // As with all template template parms, the parameter list captured
29733 // by this template template parm that corresponds to its own level
29734 // should be empty. This avoids infinite recursion when structurally
29735 // comparing two such rewritten template template parms (PR102479).
29740 // All done.
29742 }
29746 else
29748 }
29749 else
29750 {
29752 tree newconst
29764 }
29767 }
29769 /* As rewrite_template_parm, but for the whole TREE_LIST representing a
29770 template parameter. */
29772 static tree
29775 {
29790 }
29792 /* Returns a C++17 class deduction guide template based on the constructor
29793 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
29794 guide, REFERENCE_TYPE for an implicit copy/move guide, or TREE_LIST for an
29795 aggregate initialization guide. OUTER_ARGS are the template arguments
29796 for the enclosing scope of the class. */
29798 static tree
29800 {
29804 location_t loc;
29808 {
29812 }
29815 {
29817 {
29821 else
29823 }
29826 else
29836 }
29837 else
29838 {
29844 fn_tmpl
29852 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
29853 fully specialized args for the enclosing class. Strip those off, as
29854 the deduction guide won't have those template parameters. */
29857 /* Discard the 'this' parameter. */
29865 {
29868 /* For a member template constructor, we need to flatten the two
29869 template parameter lists into one, and then adjust the function
29870 signature accordingly. This gets...complicated. */
29873 /* For a member template we should have two levels of parms/args, one
29874 for the class and one for the constructor. We stripped
29875 specialized args for further enclosing classes above. */
29879 /* Template args for translating references to the two-level template
29880 parameters into references to the one-level template parameters we
29881 are creating. */
29886 /* Template parms for the constructor template. */
29889 /* Template parms for the class template. */
29893 /* Template parms for the deduction guide start as a copy of the
29894 template parms for the class. We set current_template_parms for
29895 lookup_template_class_1. */
29901 /* Now we need to rewrite the constructor parms to append them to the
29902 class parms. */
29904 {
29908 tree newelt
29914 }
29916 /* Now we have a final set of template parms to substitute into the
29917 function signature. */
29924 {
29926 /* FIXME: We'd like to avoid substituting outer template
29927 arguments into the constraint ahead of time, but the
29928 construction of tsubst_args assumes that outer arguments
29929 are already substituted in. */
29932 }
29934 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped if
29935 cp_unevaluated_operand. */
29936 cp_evaluated ev;
29939 }
29940 else
29941 {
29942 /* Substitute in the same arguments to rewrite class members into
29943 references to members of an unknown specialization. */
29944 cp_evaluated ev;
29948 {
29950 /* FIXME: As above. */
29953 }
29954 }
29959 }
29962 {
29963 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
29967 }
29971 FUNCTION_DECL,
29986 }
29988 /* Add to LIST the member types for the reshaped initializer CTOR. */
29990 static tree
29992 {
29996 {
30000 {
30006 }
30010 /* Give the trailing pack expansion parameter a default argument to
30011 match aggregate initialization behavior, even if we deduce the
30012 length of the pack separately to more than we have initializers. */
30014 /* if ei is of array type and xi is a braced-init-list or string literal,
30015 Ti is an rvalue reference to the declared type of ei */
30020 {
30022 ftype = cp_build_qualified_type
30024 ftype = (cp_build_reference_type
30026 }
30028 }
30031 }
30033 /* Return whether ETYPE is, or is derived from, a specialization of TMPL. */
30035 static bool
30037 {
30043 tree tparms = (INNERMOST_TEMPLATE_PARMS
30050 }
30054 /* Return a C++20 aggregate deduction candidate for TYPE initialized from
30055 INIT. */
30057 static tree
30059 {
30067 {
30073 }
30075 /* We might be creating a guide for a class member template, e.g.,
30077 template<typename U> struct A {
30078 template<typename T> struct B { T t; };
30079 };
30081 At this point, A will have been instantiated. Below, we need to
30082 use both A<U>::B<T> (TEMPLATE_TYPE) and A<int>::B<T> (TYPE) types. */
30083 const bool member_template_p
30087 tree template_type = (member_template_p
30093 /* No aggregate candidate for copy-initialization. */
30095 {
30099 }
30101 /* If we encounter a problem, we just won't add the candidate. */
30106 {
30111 /* If we're creating a deduction guide for a member class template,
30112 we've used the original template pattern type for the reshape_init
30113 above; this is done because we want PARMS to be a template parameter
30114 type, something that can be deduced when used as a function template
30115 parameter. At this point the outer class template has already been
30116 partially instantiated (we deferred the deduction until the enclosing
30117 scope is non-dependent). Therefore we have to partially instantiate
30118 PARMS, so that its template level is properly reduced and we don't get
30119 mismatches when deducing types using the guide with PARMS. */
30121 {
30125 }
30126 }
30128 {
30131 len;
30133 {
30139 }
30140 }
30141 else
30142 /* Aggregate initialization doesn't apply to an initializer expression. */
30146 {
30152 }
30155 }
30157 /* UGUIDES are the deduction guides for the underlying template of alias
30158 template TMPL; adjust them to be deduction guides for TMPL. */
30160 static tree
30162 {
30163 /* [over.match.class.deduct]: When resolving a placeholder for a deduced
30164 class type (9.2.8.2) where the template-name names an alias template A,
30165 the defining-type-id of A must be of the form
30167 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
30169 as specified in 9.2.8.2. The guides of A are the set of functions or
30170 function templates formed as follows. For each function or function
30171 template f in the guides of the template named by the simple-template-id
30172 of the defining-type-id, the template arguments of the return type of f
30173 are deduced from the defining-type-id of A according to the process in
30174 13.10.2.5 with the exception that deduction does not fail if not all
30175 template arguments are deduced. Let g denote the result of substituting
30176 these deductions into f. If substitution succeeds, form a function or
30177 function template f' with the following properties and add it to the set
30178 of guides of A:
30180 * The function type of f' is the function type of g.
30182 * If f is a function template, f' is a function template whose template
30183 parameter list consists of all the template parameters of A (including
30184 their default template arguments) that appear in the above deductions or
30185 (recursively) in their default template arguments, followed by the
30186 template parameters of f that were not deduced (including their default
30187 template arguments), otherwise f' is not a function template.
30189 * The associated constraints (13.5.2) are the conjunction of the
30190 associated constraints of g and a constraint that is satisfied if and only
30191 if the arguments of A are deducible (see below) from the return type.
30193 * If f is a copy deduction candidate (12.4.1.8), then f' is considered to
30194 be so as well.
30196 * If f was generated from a deduction-guide (12.4.1.8), then f' is
30197 considered to be so as well.
30199 * The explicit-specifier of f' is the explicit-specifier of g (if
30200 any). */
30210 {
30217 {
30221 /* Deduce template arguments for f from the type-id of A. */
30227 /* CWG2664: Discard any deductions, still build the guide. */
30231 /* The number of parms for f' is the number of parms of A used in
30232 the deduced arguments plus non-deduced parms of f. */
30244 /* Set current_template_parms as in build_deduction_guide. */
30252 /* First copy over the used parms of A. */
30255 {
30258 {
30263 }
30264 }
30267 /* Adjust the deduced template args for f to refer to the A parms
30268 with their new indexes. */
30272 /* Now rewrite the non-deduced parms of f. */
30275 {
30282 }
30285 /* Substitute the deduced arguments plus the rewritten template
30286 parameters into f to get g. This covers the type, copyness,
30287 guideness, and explicit-specifier. */
30288 tree g;
30289 {
30290 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped
30291 if cp_unevaluated_operand. */
30292 cp_evaluated ev;
30294 }
30298 {
30299 /* The targs are all non-dependent, so g isn't a template. */
30303 }
30312 /* Substitute the associated constraints. */
30319 /* Add a constraint that the return type matches the instantiation of
30320 A with the same template arguments. */
30323 /* FIXME this should mean they don't compare as equivalent. */
30325 {
30328 }
30331 {
30334 }
30335 }
30336 else
30337 {
30338 /* For a non-template deduction guide, if the arguments of A aren't
30339 deducible from the return type, don't add the candidate. */
30340 non_template:
30343 }
30346 }
30349 }
30351 /* True iff template arguments for TMPL can be deduced from TYPE.
30352 Used to implement CPTK_IS_DEDUCIBLE for alias CTAD according to
30353 [over.match.class.deduct].
30355 This check is specified in terms of partial specialization, so the behavior
30356 should be parallel to that of get_partial_spec_bindings. */
30358 bool
30360 {
30366 /* If tmpl is a class template, this is trivial: it's deducible if TYPE is a
30367 specialization of TMPL. */
30373 /* Otherwise it's an alias template. */
30374 again:
30379 /* We don't fail on an undeduced targ the second time through (like
30380 get_partial_spec_bindings) because we're going to try defaults. */
30383 {
30389 {
30394 }
30395 /* If the type parameter is a parameter pack, then it will be deduced
30396 to an empty parameter pack. This is another case that doesn't model
30397 well as partial specialization. */
30399 {
30400 tree arg;
30402 {
30405 }
30406 else
30410 }
30411 }
30413 /* Maybe add in default template args. This seems like a flaw in the
30414 specification in terms of partial specialization, since it says the
30415 partial specialization has the the template parameter list of A, but a
30416 partial specialization can't have default targs. */
30421 /* I believe we don't need the template_template_parm_bindings_ok_p call
30422 because coerce_template_parms did coerce_template_template_parms. */
30425 }
30427 /* Return artificial deduction guides built from the constructors of class
30428 template TMPL. */
30430 static tree
30432 {
30439 {
30440 /* Skip inherited constructors. */
30446 }
30448 /* Add implicit default constructor deduction guide. */
30450 {
30452 complain);
30454 }
30456 /* Add copy guide. */
30457 {
30460 complain);
30462 }
30465 }
30469 /* Return the non-aggregate deduction guides for deducible template TMPL. The
30470 aggregate candidate is added separately because it depends on the
30471 initializer. Set ANY_DGUIDES_P if we find a non-implicit deduction
30472 guide. */
30474 static tree
30476 {
30479 {
30483 complain);
30484 }
30485 else
30486 {
30492 else
30494 }
30496 /* Cache the deduction guides for a template. We also remember the result of
30497 lookup, and rebuild everything if it changes; should be very rare. */
30501 {
30505 }
30506 else
30507 {
30510 }
30515 else
30516 {
30520 }
30524 }
30526 /* Return whether TMPL is a (class template argument-) deducible template. */
30528 bool
30530 {
30531 /* A deducible template is either a class template or is an alias template
30532 whose defining-type-id is of the form
30534 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
30536 where the nested-name-specifier (if any) is non-dependent and the
30537 template-name of the simple-template-id names a deducible template. */
30548 }
30550 /* Deduce template arguments for the class template placeholder PTYPE for
30551 template TMPL based on the initializer INIT, and return the resulting
30552 type. */
30554 static tree
30557 {
30558 /* We should have handled this in the caller. */
30562 /* If the class was erroneous, don't try to deduce, because that
30563 can generate a lot of diagnostic. */
30569 /* Wait until the enclosing scope is non-dependent. */
30574 /* Initializing one placeholder from another. */
30585 {
30589 }
30591 {
30593 {
30594 /* Be permissive with equivalent alias templates. */
30597 bool complained
30599 "alias template deduction only available "
30604 {
30607 }
30608 }
30609 else
30611 }
30613 /* Wait until the initializer is non-dependent. */
30617 /* Don't bother with the alias rules for an equivalent template. */
30630 {
30635 {
30636 /* As an exception, the first phase in 16.3.1.7 (considering the
30637 initializer list as a single argument) is omitted if the
30638 initializer list consists of a single expression of type cv U,
30639 where U is a specialization of C or a class derived from a
30640 specialization of C. */
30644 }
30647 else
30649 }
30652 else
30655 /* Do this now to avoid problems with erroneous args later on. */
30665 /* Prune explicit deduction guides in copy-initialization context (but
30666 not copy-list-initialization). */
30669 {
30675 {
30676 /* Found a nonconverting guide, prune the candidates. */
30683 }
30684 }
30692 /* If this is list-initialization and the class has a list guide, first
30693 try deducing from the list as a single argument, as [over.match.list]. */
30695 {
30703 {
30704 /* That didn't work, now try treating the list as a sequence of
30705 arguments. */
30711 }
30712 }
30715 {
30717 " of %qT, as it has no non-explicit deduction guides or "
30720 }
30722 {
30726 }
30732 {
30734 {
30740 }
30742 }
30743 /* [over.match.list]/1: In copy-list-initialization, if an explicit
30744 constructor is chosen, the initialization is ill-formed. */
30746 {
30748 {
30750 {
30751 // TODO: Pass down location from cp_finish_decl.
30753 "explicit deduction guide selected in "
30758 }
30760 }
30761 }
30763 /* If CTAD succeeded but the type doesn't have any explicit deduction
30764 guides, this deduction might not be what the user intended. */
30766 {
30770 "%qT may not intend to support class template argument "
30774 }
30778 }
30780 /* Return true if INIT is an unparenthesized id-expression or an
30781 unparenthesized class member access. Used for the argument of
30782 decltype(auto). */
30784 bool
30786 {
30789 /* We need to be able to tell '(r)' and 'r' apart (when it's of
30790 reference type). Only the latter is an id-expression. */
30798 }
30800 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
30801 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
30802 The CONTEXT determines the context in which auto deduction is performed
30803 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
30805 OUTER_TARGS is used during template argument deduction (context == adc_unify)
30806 to properly substitute the result. It's also used in the adc_unify and
30807 adc_requirement contexts to communicate the necessary template arguments
30808 to satisfaction. OUTER_TARGS is ignored in other contexts.
30810 Additionally for adc_unify contexts TMPL is the template for which TYPE
30811 is a template parameter type.
30813 For partial-concept-ids, extra args from OUTER_TARGS, TMPL and the current
30814 scope may be appended to the list of deduced template arguments prior to
30815 determining constraint satisfaction as appropriate. */
30817 tree
30824 {
30830 /* Defining a subset of type-dependent expressions that we can deduce
30831 from ahead of time isn't worth the trouble. */
30834 /* Similarly, we can't deduce from another undeduced decl. */
30838 /* We may be doing a partial substitution, but we still want to replace
30839 auto_node. */
30843 {
30844 /* We don't recurse here because we can't deduce from a nested
30845 initializer_list. */
30849 }
30853 /* In C++23, we must deduce the type to int&& for code like
30854 decltype(auto) f(int&& x) { return (x); }
30855 or
30856 auto&& f(int x) { return x; }
30857 so we use treat_lvalue_as_rvalue_p. But don't do it for
30858 decltype(auto) f(int x) { return x; }
30859 where we should deduce 'int' rather than 'int&&'; transmogrifying
30860 INIT to an rvalue would break that. */
30861 tree r;
30871 /* C++17 class template argument deduction. */
30875 /* Nothing we can do with this, even in deduction context. */
30880 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
30881 with either a new invented type template parameter U or, if the
30882 initializer is a braced-init-list (8.5.4), with
30883 std::initializer_list<U>. */
30885 {
30890 else
30891 {
30893 {
30897 "for deduction to %<std::initializer_list%>, use copy-"
30899 }
30901 }
30902 }
30907 tree targs;
30911 {
30912 /* [dcl.struct.bind]/1 - if decomposition declaration has no ref-qualifiers
30913 and initializer has array type, deduce cv-qualified array type. */
30916 }
30918 {
30926 }
30927 else
30928 {
30933 tree tparms;
30937 else
30938 {
30942 }
30946 DEDUCE_CALL,
30949 {
30951 /* Try again at instantiation time. */
30955 /* If type is error_mark_node a diagnostic must have been
30956 emitted by now. Also, having a mention to '<type error>'
30957 in the diagnostic is not really useful to the user. */
30958 {
30961 && (auto_node
30965 init);
30966 else
30969 DEDUCE_CALL,
30971 }
30973 }
30974 }
30976 /* Check any placeholder constraints against the deduced type. */
30980 {
30982 {
30987 /* If the constraint is dependent, we need to wait until
30988 instantiation time to resolve the placeholder. */
30991 }
30998 {
31002 {
31003 /* As in satisfy_declaration_constraints. */
31007 else
31009 }
31010 }
31017 /* HACK: Compensate for callers not always communicating all levels of
31018 outer template arguments by filling in the outermost missing levels
31019 with dummy levels before checking satisfaction. We'll still crash
31020 if the constraint depends on a template argument belonging to one of
31021 these missing levels, but this hack otherwise allows us to handle a
31022 large subset of possible constraints (including all non-dependent
31023 constraints). */
31026 {
31031 }
31034 {
31036 {
31037 auto_diagnostic_group d;
31039 {
31057 }
31059 }
31061 }
31062 }
31065 /* The outer template arguments are already substituted into type
31072 }
31074 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
31075 result. */
31077 tree
31079 {
31081 {
31084 }
31088 {
31089 /* In an abbreviated function template we didn't know we were dealing
31090 with a function template when we saw the auto return type, so rebuild
31091 the return type using an auto with the correct level. */
31096 auto_vec);
31097 /* Also rebuild the constraint info in terms of the new auto. */
31105 }
31107 }
31109 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
31110 'decltype(auto)' or a deduced class template. */
31112 bool
31114 {
31119 else
31121 }
31123 /* for_each_template_parm callback for type_uses_auto. */
31125 int
31127 {
31129 }
31131 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
31132 a use of `auto'. Returns NULL_TREE otherwise. */
31134 tree
31136 {
31140 {
31141 /* The Concepts TS allows multiple autos in one type-specifier; just
31142 return the first one we find, do_auto_deduction will collect all of
31143 them. */
31147 else
31149 }
31150 else
31152 }
31154 /* Report ill-formed occurrences of auto types in ARGUMENTS. If
31155 concepts are enabled, auto is acceptable in template arguments, but
31156 only when TEMPL identifies a template class. Return TRUE if any
31157 such errors were reported. */
31159 bool
31161 {
31163 /* Only the concepts TS allows 'auto' as a type-id; it'd otherwise
31164 have already been rejected by the parser more generally. */
31167 /* If there were previous errors, nevermind. */
31171 /* If TMPL is an identifier, we're parsing and we can't tell yet
31172 whether TMPL is supposed to be a type, a function or a variable.
31173 We'll only be able to tell during template substitution, so we
31174 expect to be called again then. If concepts are enabled and we
31175 know we have a type, we're ok. */
31182 /* Quickly search for any occurrences of auto; usually there won't
31183 be any, and then we'll avoid allocating the vector. */
31191 {
31196 }
31199 }
31201 /* Recursively walk over && expressions searching for EXPR. Return a reference
31202 to that expression. */
31205 {
31209 {
31214 }
31216 }
31218 /* Convert the generic type parameters in PARM that match the types given in the
31219 range [START_IDX, END_IDX) from the current_template_parms into generic type
31220 packs. */
31222 tree
31224 {
31235 {
31236 /* Create a distinct parameter pack type from the current parm and add it
31237 to the replacement args to tsubst below into the generic function
31238 parameter. */
31252 /* Replace the current template parameter with new pack. */
31255 /* Surgically adjust the associated constraint of adjusted parameter
31256 and it's corresponding contribution to the current template
31257 requirements. */
31259 {
31265 /* If there was a constraint, we also need to replace that in
31266 the template requirements, which we've already built. */
31270 }
31271 }
31277 /* If there are more levels then build up the replacement with the outer
31278 template parms. */
31282 replacement);
31285 }
31287 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
31288 0..N-1. */
31290 void
31292 {
31295 integer_type_node,
31296 NULL_TREE),
31300 CP_BUILT_IN_INTEGER_PACK);
31301 }
31303 /* Walk the decl or type specialization table calling FN on each
31304 entry. */
31306 void
31310 {
31316 }
31318 /* Lookup the specialization of *ELT, in the decl or type
31319 specialization table. Return the SPEC that's already there, or
31320 NULL if nothing. */
31322 tree
31324 {
31334 }
31336 /* Return flags encoding whether SPEC is on the instantiation and/or
31337 specialization lists of TMPL. */
31339 unsigned
31341 {
31347 {
31350 }
31355 /* Only need to search if DECL is a partial specialization. */
31359 {
31362 }
31365 }
31367 /* Add a new specialization described by SPEC. DECL is the
31368 maybe-template decl and FLAGS is as returned from
31369 get_mergeable_specialization_flags. */
31371 void
31374 {
31377 {
31386 {
31389 }
31390 }
31393 {
31396 /* We don't distinguish different constrained partial type
31397 specializations, so there could be duplicates. Everything else
31398 must be new. */
31400 {
31406 }
31407 }
31414 {
31415 /* A partial specialization. */
31420 }
31421 }
31423 /* Set up the hash tables for template instantiations. */
31425 void
31427 {
31433 }
31435 /* Print stats about the template hash tables for -fstats. */
31437 void
31439 {
31448 }
31450 #if CHECKING_P
31454 /* Verify that build_non_dependent_expr () works, for various expressions,
31455 and that location wrappers don't affect the results. */
31457 static void
31459 {
31462 /* Verify constants, without and with location wrappers. */
31479 }
31481 /* Verify that type_dependent_expression_p () works correctly, even
31482 in the presence of location wrapper nodes. */
31484 static void
31486 {
31491 /* If no templates are involved, nothing is type-dependent. */
31497 /* Within a template, an unresolved name is always type-dependent. */
31500 /* Ensure it copes with NULL_TREE and errors. */
31504 /* A USING_DECL in a template should be type-dependent, even if wrapped
31505 with a location wrapper (PR c++/83799). */
31514 }
31516 /* Run all of the selftests within this file. */
31518 void
31520 {
31523 }