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1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2018 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". */
46 /* The type of functions taking a tree, and some additional data, and
47 returning an int. */
50 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
51 instantiations have been deferred, either because their definitions
52 were not yet available, or because we were putting off doing the work. */
54 {
57 };
72 /* Live only within one (recursive) call to tsubst_expr. We use
73 this to pass the statement expression node from the STMT_EXPR
74 to the EXPR_STMT that is its result. */
77 // -------------------------------------------------------------------------- //
78 // Local Specialization Stack
79 //
80 // Implementation of the RAII helper for creating new local
81 // specializations.
84 {
87 else
89 }
92 {
95 }
97 /* True if we've recursed into fn_type_unification too many times. */
101 {
102 tree tmpl;
103 tree args;
104 tree spec;
105 };
108 {
111 };
117 /* Contains canonical template parameter types. The vector is indexed by
118 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
119 TREE_LIST, whose TREE_VALUEs contain the canonical template
120 parameters of various types and levels. */
123 #define UNIFY_ALLOW_NONE 0
124 #define UNIFY_ALLOW_MORE_CV_QUAL 1
125 #define UNIFY_ALLOW_LESS_CV_QUAL 2
126 #define UNIFY_ALLOW_DERIVED 4
127 #define UNIFY_ALLOW_INTEGER 8
128 #define UNIFY_ALLOW_OUTER_LEVEL 16
129 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
130 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
133 tbr_incomplete_type,
134 tbr_ambiguous_baseclass,
135 tbr_success
136 };
159 tree);
216 location_t);
228 /* Make the current scope suitable for access checking when we are
229 processing T. T can be FUNCTION_DECL for instantiated function
230 template, VAR_DECL for static member variable, or TYPE_DECL for
231 alias template (needed by instantiate_decl). */
233 static void
235 {
243 else
247 {
248 saved_access_scope = tree_cons
251 }
252 }
254 /* Restore the scope set up by push_access_scope. T is the node we
255 are processing. */
257 static void
259 {
261 {
264 }
268 else
270 }
272 /* Do any processing required when DECL (a member template
273 declaration) is finished. Returns the TEMPLATE_DECL corresponding
274 to DECL, unless it is a specialization, in which case the DECL
275 itself is returned. */
277 tree
279 {
286 {
287 tree type;
295 {
299 }
301 }
305 {
307 {
310 }
311 else
313 }
314 else
318 }
320 /* Create a template info node. */
322 tree
324 {
329 }
331 /* Return the template info node corresponding to T, whatever T is. */
333 tree
335 {
357 }
359 /* Returns the template nesting level of the indicated class TYPE.
361 For example, in:
362 template <class T>
363 struct A
364 {
365 template <class U>
366 struct B {};
367 };
369 A<T>::B<U> has depth two, while A<T> has depth one.
370 Both A<T>::B<int> and A<int>::B<U> have depth one, if
371 they are instantiations, not specializations.
373 This function is guaranteed to return 0 if passed NULL_TREE so
374 that, for example, `template_class_depth (current_class_type)' is
375 always safe. */
377 int
379 {
383 {
394 else
396 }
399 }
401 /* Subroutine of maybe_begin_member_template_processing.
402 Returns true if processing DECL needs us to push template parms. */
404 static bool
406 {
412 }
414 /* Subroutine of maybe_begin_member_template_processing.
415 Push the template parms in PARMS, starting from LEVELS steps into the
416 chain, and ending at the beginning, since template parms are listed
417 innermost first. */
419 static void
421 {
429 current_template_parms
435 NULL);
437 {
446 {
453 /* Push the CONST_DECL. */
459 }
460 }
461 }
463 /* Restore the template parameter context for a member template, a
464 friend template defined in a class definition, or a non-template
465 member of template class. */
467 void
469 {
470 tree parms;
475 {
478 /* Disregard full specializations (c++/60999). */
481 }
484 {
489 {
492 }
495 }
497 /* Remember how many levels of template parameters we pushed so that
498 we can pop them later. */
500 }
502 /* Undo the effects of maybe_begin_member_template_processing. */
504 void
506 {
515 {
519 }
520 }
522 /* Return a new template argument vector which contains all of ARGS,
523 but has as its innermost set of arguments the EXTRA_ARGS. */
525 static tree
527 {
528 tree new_args;
546 }
548 /* Like add_to_template_args, but only the outermost ARGS are added to
549 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
550 (EXTRA_ARGS) levels are added. This function is used to combine
551 the template arguments from a partial instantiation with the
552 template arguments used to attain the full instantiation from the
553 partial instantiation. */
555 static tree
557 {
558 tree new_args;
560 /* If there are more levels of EXTRA_ARGS than there are ARGS,
561 something very fishy is going on. */
564 /* If *all* the new arguments will be the EXTRA_ARGS, just return
565 them. */
569 /* For the moment, we make ARGS look like it contains fewer levels. */
574 /* Now, we restore ARGS to its full dimensions. */
578 }
580 /* Return the N levels of innermost template arguments from the ARGS. */
582 tree
584 {
585 tree new_args;
591 /* If N is 1, just return the innermost set of template arguments. */
595 /* If we're not removing anything, just return the arguments we were
596 given. */
602 /* Make a new set of arguments, not containing the outer arguments. */
609 }
611 /* The inverse of get_innermost_template_args: Return all but the innermost
612 EXTRA_LEVELS levels of template arguments from the ARGS. */
614 static tree
616 {
617 tree new_args;
623 /* If N is 1, just return the outermost set of template arguments. */
627 /* If we're not removing anything, just return the arguments we were
628 given. */
633 /* Make a new set of arguments, not containing the inner arguments. */
640 }
642 /* We've got a template header coming up; push to a new level for storing
643 the parms. */
645 void
647 {
648 /* We use a non-tag-transparent scope here, which causes pushtag to
649 put tags in this scope, rather than in the enclosing class or
650 namespace scope. This is the right thing, since we want
651 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
652 global template class, push_template_decl handles putting the
653 TEMPLATE_DECL into top-level scope. For a nested template class,
654 e.g.:
656 template <class T> struct S1 {
657 template <class T> struct S2 {};
658 };
660 pushtag contains special code to insert the TEMPLATE_DECL for S2
661 at the right scope. */
667 /* Add a dummy parameter level while we process the parameter list. */
668 current_template_parms
671 current_template_parms);
672 }
674 /* This routine is called when a specialization is declared. If it is
675 invalid to declare a specialization here, an error is reported and
676 false is returned, otherwise this routine will return true. */
678 static bool
680 {
683 /* [temp.expl.spec]
685 An explicit specialization shall be declared in the namespace of
686 which the template is a member, or, for member templates, in the
687 namespace of which the enclosing class or enclosing class
688 template is a member. An explicit specialization of a member
689 function, member class or static data member of a class template
690 shall be declared in the namespace of which the class template
691 is a member. */
693 {
696 }
698 /* [temp.expl.spec]
700 In an explicit specialization declaration for a member of a class
701 template or a member template that appears in namespace scope,
702 the member template and some of its enclosing class templates may
703 remain unspecialized, except that the declaration shall not
704 explicitly specialize a class member template if its enclosing
705 class templates are not explicitly specialized as well. */
707 {
710 }
713 }
715 /* We've just seen template <>. */
717 bool
719 {
723 }
725 /* Called at then end of processing a declaration preceded by
726 template<>. */
728 void
730 {
733 }
735 /* Any template <>'s that we have seen thus far are not referring to a
736 function specialization. */
738 void
740 {
743 }
745 /* We've just seen a template header. If SPECIALIZATION is nonzero,
746 it was of the form template <>. */
748 static void
750 {
752 template_header_count++;
753 }
755 /* We're beginning an explicit instantiation. */
757 void
759 {
762 }
765 void
767 {
770 }
772 /* An explicit specialization or partial specialization of TMPL is being
773 declared. Check that the namespace in which the specialization is
774 occurring is permissible. Returns false iff it is invalid to
775 specialize TMPL in the current namespace. */
777 static bool
779 {
782 /* [tmpl.expl.spec]
784 An explicit specialization shall be declared in a namespace enclosing the
785 specialized template. An explicit specialization whose declarator-id is
786 not qualified shall be declared in the nearest enclosing namespace of the
787 template, or, if the namespace is inline (7.3.1), any namespace from its
788 enclosing namespace set. */
791 {
794 }
797 /* Same or enclosing namespace. */
799 else
800 {
806 }
807 }
809 /* SPEC is an explicit instantiation. Check that it is valid to
810 perform this explicit instantiation in the current namespace. */
812 static void
814 {
815 tree ns;
817 /* DR 275: An explicit instantiation shall appear in an enclosing
818 namespace of its template. */
824 }
826 // Returns the type of a template specialization only if that
827 // specialization needs to be defined. Otherwise (e.g., if the type has
828 // already been defined), the function returns NULL_TREE.
829 static tree
831 {
832 // An implicit instantiation of an incomplete type implies
833 // the definition of a new class template.
834 //
835 // template<typename T>
836 // struct S;
837 //
838 // template<typename T>
839 // struct S<T*>;
840 //
841 // Here, S<T*> is an implicit instantiation of S whose type
842 // is incomplete.
846 // It can also be the case that TYPE is a completed specialization.
847 // Continuing the previous example, suppose we also declare:
848 //
849 // template<typename T>
850 // requires Integral<T>
851 // struct S<T*>;
852 //
853 // Here, S<T*> refers to the specialization S<T*> defined
854 // above. However, we need to differentiate definitions because
855 // we intend to define a new partial specialization. In this case,
856 // we rely on the fact that the constraints are different for
857 // this declaration than that above.
858 //
859 // Note that we also get here for injected class names and
860 // late-parsed template definitions. We must ensure that we
861 // do not create new type declarations for those cases.
863 {
867 // If there are no template parameters, this cannot be a new
868 // partial template specializtion?
872 // The injected-class-name is not a new partial specialization.
876 // If the constraints are not the same as those of the primary
877 // then, we can probably create a new specialization.
881 {
885 }
887 // Also, if there's a pre-existing specialization with matching
888 // constraints, then this also isn't new.
891 {
899 }
901 // Create a new type node (and corresponding type decl)
902 // for the newly declared specialization.
907 /* We only need a separate type node for storing the definition of this
908 partial specialization; uses of S<T*> are unconstrained, so all are
909 equivalent. So keep TYPE_CANONICAL the same. */
912 // Build the corresponding type decl.
918 }
921 }
923 /* The TYPE is being declared. If it is a template type, that means it
924 is a partial specialization. Do appropriate error-checking. */
926 tree
928 {
929 tree context;
934 /* A lambda that appears in specialization context is not itself a
935 specialization. */
940 {
944 }
949 {
955 else
958 }
960 {
961 /* This is for ordinary explicit specialization and partial
962 specialization of a template class such as:
964 template <> class C<int>;
966 or:
968 template <class T> class C<T*>;
970 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
973 {
980 {
985 }
986 }
992 /* Trying to define a specialization either without a template<> header
993 or in an inappropriate place. We've already given an error, so just
994 bail now so we don't actually define the specialization. */
996 }
1002 {
1003 /* This is for an explicit specialization of member class
1004 template according to [temp.expl.spec/18]:
1006 template <> template <class U> class C<int>::D;
1008 The context `C<int>' must be an implicit instantiation.
1009 Otherwise this is just a member class template declared
1010 earlier like:
1012 template <> class C<int> { template <class U> class D; };
1013 template <> template <class U> class C<int>::D;
1015 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1016 while in the second case, `C<int>::D' is a primary template
1017 and `C<T>::D' may not exist. */
1021 {
1022 tree t;
1027 {
1032 }
1034 /* Check for invalid specialization after instantiation:
1036 template <> template <> class C<int>::D<int>;
1037 template <> template <class U> class C<int>::D; */
1041 {
1045 {
1046 /* We already have a full specialization of this partial
1047 instantiation, or a full specialization has been
1048 looked up but not instantiated. Reassign it to the
1049 new member specialization template. */
1050 spec_entry elt;
1062 spec_entry **slot
1067 }
1068 else
1069 /* But if we've had an implicit instantiation, that's a
1070 problem ([temp.expl.spec]/6). */
1073 }
1075 /* Mark TYPE as a specialization. And as a result, we only
1076 have one level of template argument for the innermost
1077 class template. */
1082 }
1083 }
1085 {
1086 /* Someday C++0x may allow for enum template specialization. */
1091 else
1092 {
1095 }
1096 }
1099 }
1101 /* Returns nonzero if we can optimize the retrieval of specializations
1102 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1103 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1107 {
1110 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1111 parameter. */
1113 /* The optimized lookup depends on the fact that the
1114 template arguments for the member function template apply
1115 purely to the containing class, which is not true if the
1116 containing class is an explicit or partial
1117 specialization. */
1121 /* It is possible to have a template that is not a member
1122 template and is not a member of a template class:
1124 template <typename T>
1125 struct S { friend A::f(); };
1127 Here, the friend function is a template, but the context does
1128 not have template information. The optimized lookup relies
1129 on having ARGS be the template arguments for both the class
1130 and the function template. */
1132 }
1134 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1135 gone through coerce_template_parms by now. */
1137 static void
1139 {
1141 {
1150 /* Allow typedefs on the type of a non-type argument, since a
1152 else
1154 }
1155 }
1157 static void
1159 {
1164 }
1166 /* Retrieve the specialization (in the sense of [temp.spec] - a
1167 specialization is either an instantiation or an explicit
1168 specialization) of TMPL for the given template ARGS. If there is
1169 no such specialization, return NULL_TREE. The ARGS are a vector of
1170 arguments, or a vector of vectors of arguments, in the case of
1171 templates with more than one level of parameters.
1173 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1174 then we search for a partial specialization matching ARGS. This
1175 parameter is ignored if TMPL is not a class template.
1177 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1178 result is a NONTYPE_ARGUMENT_PACK. */
1180 static tree
1182 {
1192 /* There should be as many levels of arguments as there are
1193 levels of parameters. */
1202 /* Lambda functions in templates aren't instantiated normally, but through
1203 tsubst_lambda_expr. */
1208 {
1209 /* The template arguments actually apply to the containing
1210 class. Find the class specialization with those
1211 arguments. */
1213 tree class_specialization
1218 /* Find the instance of TMPL. */
1221 {
1224 /* using-declarations can add base methods to the method vec,
1225 and we don't want those here. */
1228 }
1230 }
1231 else
1232 {
1234 spec_entry elt;
1243 else
1251 }
1254 }
1256 /* Like retrieve_specialization, but for local declarations. */
1258 tree
1260 {
1266 }
1268 /* Returns nonzero iff DECL is a specialization of TMPL. */
1270 int
1272 {
1273 tree t;
1276 {
1282 }
1283 else
1284 {
1293 }
1296 }
1298 /* Returns nonzero iff DECL is a specialization of friend declaration
1299 FRIEND_DECL according to [temp.friend]. */
1301 bool
1303 {
1310 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1311 of a template class, we want to check if DECL is a specialization
1312 if this. */
1316 {
1317 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1320 }
1325 /* There is nothing to do if this is not a template friend. */
1332 /* [temp.friend/6]
1333 A member of a class template may be declared to be a friend of a
1334 non-template class. In this case, the corresponding member of
1335 every specialization of the class template is a friend of the
1336 class granting friendship.
1338 For example, given a template friend declaration
1340 template <class T> friend void A<T>::f();
1342 the member function below is considered a friend
1344 template <> struct A<int> {
1345 void f();
1346 };
1348 For this type of template friend, TEMPLATE_DEPTH below will be
1349 nonzero. To determine if DECL is a friend of FRIEND, we first
1350 check if the enclosing class is a specialization of another. */
1357 {
1358 /* Next, we check the members themselves. In order to handle
1359 a few tricky cases, such as when FRIEND_DECL's are
1361 template <class T> friend void A<T>::g(T t);
1362 template <class T> template <T t> friend void A<T>::h();
1364 and DECL's are
1366 void A<int>::g(int);
1367 template <int> void A<int>::h();
1369 we need to figure out ARGS, the template arguments from
1370 the context of DECL. This is required for template substitution
1371 of `T' in the function parameter of `g' and template parameter
1372 of `h' in the above examples. Here ARGS corresponds to `int'. */
1379 {
1381 {
1384 else
1386 current_depth++;
1387 }
1389 }
1392 {
1394 tree friend_type;
1395 tree decl_type;
1396 tree friend_args_type;
1397 tree decl_args_type;
1399 /* Make sure that both DECL and FRIEND_DECL are templates or
1400 non-templates. */
1406 {
1407 /* If both are templates, check template parameter list. */
1408 tree friend_parms
1413 friend_parms))
1417 }
1418 else
1426 /* Check if return types match. */
1430 /* Check if function parameter types match, ignoring the
1431 `this' parameter. */
1440 }
1441 else
1442 {
1443 /* DECL is a TYPE_DECL */
1447 /* Make sure that both DECL and FRIEND_DECL are templates or
1448 non-templates. */
1449 is_template
1456 {
1457 tree friend_parms;
1458 /* If both are templates, check the name of the two
1459 TEMPLATE_DECL's first because is_friend didn't. */
1464 /* Now check template parameter list. */
1465 friend_parms
1468 return comp_template_parms
1470 friend_parms);
1471 }
1472 else
1475 }
1476 }
1478 }
1480 /* Register the specialization SPEC as a specialization of TMPL with
1481 the indicated ARGS. IS_FRIEND indicates whether the specialization
1482 is actually just a friend declaration. ATTRLIST is the list of
1483 attributes that the specialization is declared with or NULL when
1484 it isn't. Returns SPEC, or an equivalent prior declaration, if
1485 available.
1487 We also store instantiations of field packs in the hash table, even
1488 though they are not themselves templates, to make lookup easier. */
1490 static tree
1492 hashval_t hash)
1493 {
1494 tree fn;
1496 spec_entry elt;
1504 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1505 register it; we want the corresponding TEMPLATE_DECL instead.
1506 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1507 the more obvious `uses_template_parms (spec)' to avoid problems
1508 with default function arguments. In particular, given
1509 something like this:
1511 template <class T> void f(T t1, T t = T())
1513 the default argument expression is not substituted for in an
1514 instantiation unless and until it is actually needed. */
1518 /* We don't put these specializations in the hash table, but we might
1519 want to give an error about a mismatch. */
1521 else
1522 {
1530 slot =
1534 else
1536 }
1538 /* We can sometimes try to re-register a specialization that we've
1539 already got. In particular, regenerate_decl_from_template calls
1540 duplicate_decls which will update the specialization list. But,
1541 we'll still get called again here anyhow. It's more convenient
1542 to simply allow this than to try to prevent it. */
1546 {
1548 {
1551 {
1553 fn);
1555 }
1556 else
1557 {
1558 tree clone;
1559 /* This situation should occur only if the first
1560 specialization is an implicit instantiation, the
1561 second is an explicit specialization, and the
1562 implicit instantiation has not yet been used. That
1563 situation can occur if we have implicitly
1564 instantiated a member function and then specialized
1565 it later.
1567 We can also wind up here if a friend declaration that
1568 looked like an instantiation turns out to be a
1569 specialization:
1571 template <class T> void foo(T);
1572 class S { friend void foo<>(int) };
1573 template <> void foo(int);
1575 We transform the existing DECL in place so that any
1576 pointers to it become pointers to the updated
1577 declaration.
1579 If there was a definition for the template, but not
1580 for the specialization, we want this to look as if
1581 there were no definition, and vice versa. */
1584 /* The call to duplicate_decls will have applied
1585 [temp.expl.spec]:
1587 An explicit specialization of a function template
1588 is inline only if it is explicitly declared to be,
1589 and independently of whether its function template
1590 is.
1592 to the primary function; now copy the inline bits to
1593 the various clones. */
1595 {
1602 }
1606 }
1607 }
1609 {
1612 /* We've already complained in duplicate_decls. */
1616 /* Dup decl failed, but this is a new definition. Set the
1617 line number so any errors match this new
1618 definition. */
1622 }
1623 }
1627 /* A specialization must be declared in the same namespace as the
1628 template it is specializing. */
1634 {
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. */
1652 }
1655 }
1657 /* Returns true iff two spec_entry nodes are equivalent. */
1661 bool
1663 {
1670 /* tmpl could be a FIELD_DECL for a capture pack. */
1674 {
1675 /* Partial specializations of a variable template can be distinguished by
1676 constraints. */
1680 }
1684 }
1686 /* Returns a hash for a template TMPL and template arguments ARGS. */
1688 static hashval_t
1690 {
1693 }
1695 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1696 ignoring SPEC. */
1698 hashval_t
1700 {
1702 }
1704 /* Recursively calculate a hash value for a template argument ARG, for use
1705 in the hash tables of template specializations. */
1707 hashval_t
1709 {
1729 {
1737 {
1742 }
1764 {
1768 {
1771 }
1773 }
1777 {
1780 }
1791 val = iterative_hash_template_arg
1803 val);
1805 val);
1814 /* A lambda can't appear in a template arg, but don't crash on
1815 erroneous input. */
1827 /* Now hash operands as usual. */
1832 }
1835 {
1838 {
1839 // We want an alias specialization that survived strip_typedefs
1840 // to hash differently from its TYPE_CANONICAL, to avoid hash
1841 // collisions that compare as different in template_args_equal.
1842 // These could be dependent specializations that strip_typedefs
1843 // left alone, or untouched specializations because
1844 // coerce_template_parms returns the unconverted template
1845 // arguments if it sees incomplete argument packs.
1848 }
1851 val);
1854 /* Otherwise just compare the types during lookup. */
1863 {
1868 }
1869 }
1872 }
1874 /* Unregister the specialization SPEC as a specialization of TMPL.
1875 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1876 if the SPEC was listed as a specialization of TMPL.
1878 Note that SPEC has been ggc_freed, so we can't look inside it. */
1880 bool
1882 {
1884 spec_entry elt;
1892 {
1897 }
1900 }
1902 /* Like register_specialization, but for local declarations. We are
1903 registering SPEC, an instantiation of TMPL. */
1905 void
1907 {
1910 }
1912 /* TYPE is a class type. Returns true if TYPE is an explicitly
1913 specialized class. */
1915 bool
1917 {
1921 }
1923 /* Print the list of functions at FNS, going through all the overloads
1924 for each element of the list. Alternatively, FNS can not be a
1925 TREE_LIST, in which case it will be printed together with all the
1926 overloads.
1928 MORE and *STR should respectively be FALSE and NULL when the function
1929 is called from the outside. They are used internally on recursive
1930 calls. print_candidates manages the two parameters and leaves NULL
1931 in *STR when it ends. */
1933 static void
1935 {
1939 else
1941 {
1947 {
1950 else
1953 }
1955 }
1956 }
1958 /* Print the list of candidate FNS in an error message. FNS can also
1959 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1961 void
1963 {
1967 }
1969 /* Get a (possibly) constrained template declaration for the
1970 purpose of ordering candidates. */
1971 static tree
1973 {
1979 }
1981 /* Among candidates having the same signature, return the
1982 most constrained or NULL_TREE if there is no best candidate.
1983 If the signatures of candidates vary (e.g., template
1984 specialization vs. member function), then there can be no
1985 most constrained.
1987 Note that we don't compare constraints on the functions
1988 themselves, but rather those of their templates. */
1989 static tree
1991 {
1992 // Try to find the best candidate in a first pass.
1995 {
2002 }
2004 // Verify that the champ is better than previous candidates.
2009 }
2012 }
2015 /* Returns the template (one of the functions given by TEMPLATE_ID)
2016 which can be specialized to match the indicated DECL with the
2017 explicit template args given in TEMPLATE_ID. The DECL may be
2018 NULL_TREE if none is available. In that case, the functions in
2019 TEMPLATE_ID are non-members.
2021 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2022 specialization of a member template.
2024 The TEMPLATE_COUNT is the number of references to qualifying
2025 template classes that appeared in the name of the function. See
2026 check_explicit_specialization for a more accurate description.
2028 TSK indicates what kind of template declaration (if any) is being
2029 declared. TSK_TEMPLATE indicates that the declaration given by
2030 DECL, though a FUNCTION_DECL, has template parameters, and is
2031 therefore a template function.
2033 The template args (those explicitly specified and those deduced)
2034 are output in a newly created vector *TARGS_OUT.
2036 If it is impossible to determine the result, an error message is
2037 issued. The error_mark_node is returned to indicate failure. */
2039 static tree
2041 tree decl,
2045 tmpl_spec_kind tsk)
2046 {
2047 tree fns;
2048 tree targs;
2049 tree explicit_targs;
2052 /* A TREE_LIST of templates of which DECL may be a specialization.
2053 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2054 corresponding TREE_PURPOSE is the set of template arguments that,
2055 when used to instantiate the template, would produce a function
2056 with the signature of DECL. */
2066 /* We shouldn't be specializing a member template of an
2067 unspecialized class template; we already gave an error in
2068 check_specialization_scope, now avoid crashing. */
2072 {
2075 }
2083 /* Check for baselinks. */
2088 {
2091 }
2093 {
2096 }
2098 /* Count the number of template headers specified for this
2099 specialization. */
2109 {
2112 tf_warning_or_error,
2116 }
2118 {
2122 {
2123 tree decl_arg_types;
2124 tree fn_arg_types;
2125 tree insttype;
2127 /* In case of explicit specialization, we need to check if
2128 the number of template headers appearing in the specialization
2129 is correct. This is usually done in check_explicit_specialization,
2130 but the check done there cannot be exhaustive when specializing
2131 member functions. Consider the following code:
2133 template <> void A<int>::f(int);
2134 template <> template <> void A<int>::f(int);
2136 Assuming that A<int> is not itself an explicit specialization
2137 already, the first line specializes "f" which is a non-template
2138 member function, whilst the second line specializes "f" which
2139 is a template member function. So both lines are syntactically
2140 correct, and check_explicit_specialization does not reject
2141 them.
2143 Here, we can do better, as we are matching the specialization
2144 against the declarations. We count the number of template
2145 headers, and we check if they match TEMPLATE_COUNT + 1
2146 (TEMPLATE_COUNT is the number of qualifying template classes,
2147 plus there must be another header for the member template
2148 itself).
2150 Notice that if header_count is zero, this is not a
2151 specialization but rather a template instantiation, so there
2152 is no check we can perform here. */
2156 /* Check that the number of template arguments at the
2157 innermost level for DECL is the same as for FN. */
2165 /* DECL might be a specialization of FN. */
2169 /* For a non-static member function, we need to make sure
2170 that the const qualification is the same. Since
2171 get_bindings does not try to merge the "this" parameter,
2172 we must do the comparison explicitly. */
2174 {
2179 /* And the ref-qualification. */
2183 }
2185 /* Skip the "this" parameter and, for constructors of
2186 classes with virtual bases, the VTT parameter. A
2187 full specialization of a constructor will have a VTT
2188 parameter, but a template never will. */
2189 decl_arg_types
2191 fn_arg_types
2194 /* Function templates cannot be specializations; there are
2195 no partial specializations of functions. Therefore, if
2196 the type of DECL does not match FN, there is no
2197 match.
2199 Note that it should never be the case that we have both
2200 candidates added here, and for regular member functions
2201 below. */
2203 {
2207 }
2209 /* See whether this function might be a specialization of this
2210 template. Suppress access control because we might be trying
2211 to make this specialization a friend, and we have already done
2212 access control for the declaration of the specialization. */
2218 /* We cannot deduce template arguments that when used to
2219 specialize TMPL will produce DECL. */
2223 /* We deduced something involving 'auto', which isn't a valid
2224 template argument. */
2227 /* Remove, from the set of candidates, all those functions
2228 whose constraints are not satisfied. */
2232 // Then, try to form the new function type.
2236 fn_arg_types
2241 /* Save this template, and the arguments deduced. */
2243 }
2245 /* FN is an ordinary member function, and we need a
2246 specialization of a member template. */
2247 ;
2249 /* We can get IDENTIFIER_NODEs here in certain erroneous
2250 cases. */
2251 ;
2253 /* This is just an ordinary non-member function. Nothing can
2254 be a specialization of that. */
2255 ;
2257 /* Cannot specialize functions that are created implicitly. */
2258 ;
2259 else
2260 {
2261 tree decl_arg_types;
2263 /* This is an ordinary member function. However, since
2264 we're here, we can assume its enclosing class is a
2265 template class. For example,
2267 template <typename T> struct S { void f(); };
2268 template <> void S<int>::f() {}
2270 Here, S<int>::f is a non-template, but S<int> is a
2271 template class. If FN has the same type as DECL, we
2272 might be in business. */
2275 /* Its enclosing class is an explicit specialization
2276 of a template class. This is not a candidate. */
2281 /* The return types differ. */
2284 /* Adjust the type of DECL in case FN is a static member. */
2291 decl_arg_types))
2299 // If the deduced arguments do not satisfy the constraints,
2300 // this is not a candidate.
2304 // Add the candidate.
2306 }
2307 }
2310 {
2311 /* We have:
2313 [temp.expl.spec]
2315 It is possible for a specialization with a given function
2316 signature to be instantiated from more than one function
2317 template. In such cases, explicit specification of the
2318 template arguments must be used to uniquely identify the
2319 function template specialization being specialized.
2321 Note that here, there's no suggestion that we're supposed to
2322 determine which of the candidate templates is most
2323 specialized. However, we, also have:
2325 [temp.func.order]
2327 Partial ordering of overloaded function template
2328 declarations is used in the following contexts to select
2329 the function template to which a function template
2330 specialization refers:
2332 -- when an explicit specialization refers to a function
2333 template.
2335 So, we do use the partial ordering rules, at least for now.
2336 This extension can only serve to make invalid programs valid,
2337 so it's safe. And, there is strong anecdotal evidence that
2338 the committee intended the partial ordering rules to apply;
2339 the EDG front end has that behavior, and John Spicer claims
2340 that the committee simply forgot to delete the wording in
2341 [temp.expl.spec]. */
2344 {
2347 }
2348 }
2350 // Concepts allows multiple declarations of member functions
2351 // with the same signature. Like above, we need to rely on
2352 // on the partial ordering of those candidates to determine which
2353 // is the best.
2355 {
2357 {
2360 }
2361 }
2364 {
2371 else
2374 }
2378 {
2384 }
2386 /* We have one, and exactly one, match. */
2388 {
2392 // Propagate the candidate's constraints to the declaration.
2395 /* DECL is a re-declaration or partial instantiation of a template
2396 function. */
2399 /* It was a specialization of an ordinary member function in a
2400 template class. */
2402 }
2404 /* It was a specialization of a template. */
2407 {
2412 }
2413 else
2416 }
2418 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2419 but with the default argument values filled in from those in the
2420 TMPL_TYPES. */
2422 static tree
2424 tree tmpl_types)
2425 {
2426 tree new_spec_types;
2434 /* Substitute into the rest of the list. */
2435 new_spec_types =
2439 /* Add the default argument for this parameter. */
2442 new_spec_types);
2443 }
2445 /* DECL is an explicit specialization. Replicate default arguments
2446 from the template it specializes. (That way, code like:
2448 template <class T> void f(T = 3);
2449 template <> void f(double);
2450 void g () { f (); }
2452 works, as required.) An alternative approach would be to look up
2453 the correct default arguments at the call-site, but this approach
2454 is consistent with how implicit instantiations are handled. */
2456 static void
2458 {
2459 tree tmpl;
2460 tree spec_types;
2461 tree tmpl_types;
2462 tree new_spec_types;
2463 tree old_type;
2464 tree new_type;
2465 tree t;
2470 /* See if there's anything we need to do. */
2483 {
2484 /* Remove the this pointer, but remember the object's type for
2485 CV quals. */
2491 {
2492 /* DECL may contain more parameters than TMPL due to the extra
2493 in-charge parameter in constructors and destructors. */
2496 }
2498 {
2501 }
2502 }
2504 /* Compute the merged default arguments. */
2505 new_spec_types =
2508 /* Compute the new FUNCTION_TYPE. */
2510 {
2514 new_spec_types);
2517 /* Put the in-charge parameter back. */
2520 new_spec_types);
2524 new_spec_types);
2525 }
2526 else
2528 new_spec_types);
2538 }
2540 /* Return the number of template headers we expect to see for a definition
2541 or specialization of CTYPE or one of its non-template members. */
2543 int
2545 {
2549 {
2550 /* You're supposed to have one `template <...>' for every
2551 template class, but you don't need one for a full
2552 specialization. For example:
2554 template <class T> struct S{};
2555 template <> struct S<int> { void f(); };
2556 void S<int>::f () {}
2558 is correct; there shouldn't be a `template <>' for the
2559 definition of `S<int>::f'. */
2561 /* If CTYPE does not have template information of any
2562 kind, then it is not a template, nor is it nested
2563 within a template. */
2571 }
2574 }
2576 /* Do a simple sanity check on the template headers that precede the
2577 variable declaration DECL. */
2579 void
2581 {
2586 {
2589 "variable templates only available with "
2592 // Namespace-scope variable templates should have a template header.
2594 }
2596 {
2598 "too many template headers for %qD "
2604 "members of an explicitly specialized class are defined "
2606 }
2607 }
2609 /* An explicit specialization whose declarator-id or class-head-name is not
2610 qualified shall be declared in the nearest enclosing namespace of the
2611 template, or, if the namespace is inline (7.3.1), any namespace from its
2612 enclosing namespace set.
2614 If the name declared in the explicit instantiation is an unqualified name,
2615 the explicit instantiation shall appear in the namespace where its template
2616 is declared or, if that namespace is inline (7.3.1), any namespace from its
2617 enclosing namespace set. */
2619 void
2621 {
2626 {
2632 /* This was allowed in C++98, so only pedwarn. */
2634 "outside its namespace must use a nested-name-"
2636 }
2637 }
2639 /* Warn for a template specialization SPEC that is missing some of a set
2640 of function or type attributes that the template TEMPL is declared with.
2641 ATTRLIST is a list of additional attributes that SPEC should be taken
2642 to ultimately be declared with. */
2644 static void
2646 {
2653 /* Avoid warning if either declaration or its type is deprecated. */
2675 /* Avoid warning if the primary has no attributes. */
2679 /* Avoid warning if either declaration contains an attribute on
2680 the white list below. */
2683 };
2691 /* Avoid warning if the difference between the primary and
2692 the specialization is not in one of the attributes below. */
2696 };
2698 /* Put together a list of the black listed attributes that the primary
2699 template is declared with that the specialization is not, in case
2700 it's not apparent from the most recent declaration of the primary. */
2702 pretty_printer str;
2705 {
2707 {
2712 {
2722 }
2723 }
2724 }
2731 spec))
2737 }
2739 /* Check to see if the function just declared, as indicated in
2740 DECLARATOR, and in DECL, is a specialization of a function
2741 template. We may also discover that the declaration is an explicit
2742 instantiation at this point.
2744 Returns DECL, or an equivalent declaration that should be used
2745 instead if all goes well. Issues an error message if something is
2746 amiss. Returns error_mark_node if the error is not easily
2747 recoverable.
2749 FLAGS is a bitmask consisting of the following flags:
2751 2: The function has a definition.
2752 4: The function is a friend.
2754 The TEMPLATE_COUNT is the number of references to qualifying
2755 template classes that appeared in the name of the function. For
2756 example, in
2758 template <class T> struct S { void f(); };
2759 void S<int>::f();
2761 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2762 classes are not counted in the TEMPLATE_COUNT, so that in
2764 template <class T> struct S {};
2765 template <> struct S<int> { void f(); }
2766 template <> void S<int>::f();
2768 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2769 invalid; there should be no template <>.)
2771 If the function is a specialization, it is marked as such via
2772 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2773 is set up correctly, and it is added to the list of specializations
2774 for that template. */
2776 tree
2778 tree decl,
2781 tree attrlist)
2782 {
2791 tmpl_spec_kind tsk;
2794 {
2797 else
2799 }
2800 else
2804 {
2807 {
2810 }
2812 {
2814 /* This could be something like:
2816 template <class T> void f(T);
2817 class S { friend void f<>(int); } */
2819 else
2820 {
2821 /* This case handles bogus declarations like template <>
2822 template <class T> void f<int>(); */
2825 declarator);
2827 }
2828 }
2832 /* The error has already been reported in
2833 check_specialization_scope. */
2839 /* Fall through. */
2852 decl);
2855 else
2859 /* Fall through. */
2865 /* In cases like template<> constexpr bool v = true;
2866 We'll give an error in check_template_variable. */
2872 else
2878 {
2879 /* This case handles bogus declarations like template <>
2880 template <class T> void f<int>(); */
2884 declarator);
2886 {
2887 /* Partial specialization of variable template. */
2891 }
2895 else
2899 ok:;
2900 }
2903 /* This is a specialization of a member template, without
2904 specialization the containing class. Something like:
2906 template <class T> struct S {
2907 template <class U> void f (U);
2908 };
2909 template <> template <class U> void S<int>::f(U) {}
2911 That's a specialization -- but of the entire template. */
2917 }
2920 /* This doesn't apply to variable templates. */
2923 {
2927 {
2931 }
2932 }
2935 {
2940 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2942 {
2943 tree fns;
2948 else
2949 {
2950 /* If there is no class context, the explicit instantiation
2951 must be at namespace scope. */
2954 /* Find the namespace binding, using the declaration
2955 context. */
2959 /* If lookup fails, look for a friend declaration so we can
2960 give a better diagnostic. */
2966 {
2969 }
2970 }
2973 }
2979 {
2981 /* A specialization in class scope. This is invalid,
2982 but the error will already have been flagged by
2983 check_specialization_scope. */
2985 else
2986 {
2987 /* It's not valid to write an explicit instantiation in
2988 class scope, e.g.:
2990 class C { template void f(); }
2992 This case is caught by the parser. However, on
2993 something like:
2995 template class C { void f(); };
2997 (which is invalid) we can get here. The error will be
2998 issued later. */
2999 ;
3000 }
3003 }
3006 {
3007 // We'll match variable templates in start_decl.
3011 /* Find the list of functions in ctype that have the same
3012 name as the declared function. */
3016 {
3020 {
3021 /* From [temp.expl.spec]:
3023 If such an explicit specialization for the member
3024 of a class template names an implicitly-declared
3025 special member function (clause _special_), the
3026 program is ill-formed.
3028 Similar language is found in [temp.explicit]. */
3031 }
3034 }
3036 /* For a type-conversion operator, We might be looking for
3037 `operator int' which will be a specialization of
3038 `operator T'. Grab all the conversion operators, and
3039 then select from them. */
3044 {
3047 }
3048 else
3050 }
3052 /* Figure out what exactly is being specialized at this point.
3053 Note that for an explicit instantiation, even one for a
3054 member function, we cannot tell a priori whether the
3055 instantiation is for a member template, or just a member
3056 function of a template class. Even if a member template is
3057 being instantiated, the member template arguments may be
3058 elided if they can be deduced from the rest of the
3059 declaration. */
3062 member_specialization,
3063 template_count,
3064 tsk);
3067 /* We couldn't figure out what this declaration was
3068 specializing. */
3070 else
3071 {
3074 {
3076 "friend declaration %qD is not visible to "
3080 }
3088 {
3089 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3090 is done by do_decl_instantiation later. */
3096 {
3097 /* If TMPL is not the most general template (for
3098 example, if TMPL is a friend template that is
3099 injected into namespace scope), then there will
3100 be too many levels of TARGS. Remove some of them
3101 here. */
3103 tree new_targs;
3110 }
3113 }
3115 /* If we thought that the DECL was a member function, but it
3116 turns out to be specializing a static member function,
3117 make DECL a static member function as well. */
3123 /* If this is a specialization of a member template of a
3124 template class, we want to return the TEMPLATE_DECL, not
3125 the specialization of it. */
3127 {
3132 {
3133 tree parm;
3137 /* We want to use the argument list specified in the
3138 definition, not in the original declaration. */
3143 }
3146 }
3148 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3154 /* Inherit default function arguments from the template
3155 DECL is specializing. */
3159 /* This specialization has the same protection as the
3160 template it specializes. */
3164 /* 7.1.1-1 [dcl.stc]
3166 A storage-class-specifier shall not be specified in an
3167 explicit specialization...
3169 The parser rejects these, so unless action is taken here,
3170 explicit function specializations will always appear with
3171 global linkage.
3173 The action recommended by the C++ CWG in response to C++
3174 defect report 605 is to make the storage class and linkage
3175 of the explicit specialization match the templated function:
3177 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3178 */
3180 {
3184 /* A concept cannot be specialized. */
3186 {
3188 gen_tmpl);
3190 }
3192 /* This specialization has the same linkage and visibility as
3193 the function template it specializes. */
3196 {
3199 }
3202 {
3205 }
3206 }
3208 /* If DECL is a friend declaration, declared using an
3209 unqualified name, the namespace associated with DECL may
3210 have been set incorrectly. For example, in:
3212 template <typename T> void f(T);
3213 namespace N {
3214 struct S { friend void f<int>(int); }
3215 }
3217 we will have set the DECL_CONTEXT for the friend
3218 declaration to N, rather than to the global namespace. */
3223 /* This is not really a declaration of a specialization.
3224 It's just the name of an instantiation. But, it's not
3225 a request for an instantiation, either. */
3228 /* A specialization is not necessarily COMDAT. */
3234 /* If this is a full specialization, register it so that we can find
3235 it again. Partial specializations will be registered in
3236 process_partial_specialization. */
3238 {
3243 }
3246 /* A 'structor should already have clones. */
3252 }
3253 }
3256 }
3258 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3259 parameters. These are represented in the same format used for
3260 DECL_TEMPLATE_PARMS. */
3262 int
3264 {
3265 const_tree p1;
3266 const_tree p2;
3274 {
3286 {
3290 /* If either of the template parameters are invalid, assume
3291 they match for the sake of error recovery. */
3304 }
3305 }
3308 /* One set of parameters has more parameters lists than the
3309 other. */
3313 }
3315 /* Determine whether PARM is a parameter pack. */
3317 bool
3319 {
3320 /* Determine if we have a non-type template parameter pack. */
3327 /* If this is a list of template parameters, we could get a
3328 TYPE_DECL or a TEMPLATE_DECL. */
3332 /* Otherwise it must be a type template parameter. */
3336 }
3338 /* Determine if T is a function parameter pack. */
3340 bool
3342 {
3346 }
3348 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3349 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3351 tree
3353 {
3360 }
3362 /* Return true iff the function parameter PARAM_DECL was expanded
3363 from the function parameter pack PACK. */
3365 bool
3367 {
3372 /* The parameter pack and its pack arguments have the same
3373 DECL_PARM_INDEX. */
3375 }
3377 /* Determine whether ARGS describes a variadic template args list,
3378 i.e., one that is terminated by a template argument pack. */
3380 static bool
3382 {
3384 tree last_parm;
3398 }
3400 /* Generate a new name for the parameter pack name NAME (an
3401 IDENTIFIER_NODE) that incorporates its */
3403 static tree
3405 {
3406 /* Munge the name to include the parameter index. */
3407 #define NUMBUF_LEN 128
3421 }
3423 /* Return true if T is a primary function, class or alias template
3424 specialization, not including the template pattern. */
3426 bool
3428 {
3444 }
3446 /* Return true if PARM is a template template parameter. */
3448 bool
3450 {
3452 }
3454 /* Return true iff PARM is a DECL representing a type template
3455 parameter. */
3457 bool
3459 {
3464 }
3466 /* Return the template parameters of T if T is a
3467 primary template instantiation, NULL otherwise. */
3469 tree
3471 {
3476 parms = INNERMOST_TEMPLATE_PARMS
3480 }
3482 /* Return the template parameters of the LEVELth level from the full list
3483 of template parameters PARMS. */
3485 tree
3487 {
3488 tree p;
3499 }
3501 /* Returns the template arguments of T if T is a template instantiation,
3502 NULL otherwise. */
3504 tree
3506 {
3514 }
3516 /* Return the argument pack elements of T if T is a template argument pack,
3517 NULL otherwise. */
3519 tree
3521 {
3527 }
3529 /* In an ARGUMENT_PACK_SELECT, the actual underlying argument that the
3530 ARGUMENT_PACK_SELECT represents. */
3532 static tree
3534 {
3538 /* If the selected argument is an expansion E, that most likely means we were
3539 called from gen_elem_of_pack_expansion_instantiation during the
3540 substituting of an argument pack (of which the Ith element is a pack
3541 expansion, where I is ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
3542 In this case, the Ith element resulting from this substituting is going to
3543 be a pack expansion, which pattern is the pattern of E. Let's return the
3544 pattern of E, and gen_elem_of_pack_expansion_instantiation will build the
3545 resulting pack expansion from it. */
3547 {
3548 /* Make sure we aren't throwing away arg info. */
3551 }
3554 }
3557 /* True iff FN is a function representing a built-in variadic parameter
3558 pack. */
3560 bool
3562 {
3572 }
3574 /* True iff CALL is a call to a function representing a built-in variadic
3575 parameter pack. */
3577 static bool
3579 {
3583 }
3585 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3587 static tree
3589 tree in_decl)
3590 {
3596 {
3598 {
3601 }
3606 }
3607 else
3608 {
3612 /* Calculate the largest value of len that won't make the size of the vec
3613 overflow an int. The compiler will exceed resource limits long before
3614 this, but it seems a decent place to diagnose. */
3618 {
3623 }
3631 }
3632 }
3634 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3635 CALL. */
3637 static tree
3639 tree in_decl)
3640 {
3650 }
3652 /* Structure used to track the progress of find_parameter_packs_r. */
3653 struct find_parameter_pack_data
3654 {
3655 /* TREE_LIST that will contain all of the parameter packs found by
3656 the traversal. */
3659 /* Set of AST nodes that have been visited by the traversal. */
3662 /* True iff we're making a type pack expansion. */
3664 };
3666 /* Identifies all of the argument packs that occur in a template
3667 argument and appends them to the TREE_LIST inside DATA, which is a
3668 find_parameter_pack_data structure. This is a subroutine of
3669 make_pack_expansion and uses_parameter_packs. */
3670 static tree
3672 {
3678 /* Handle type aliases/typedefs. */
3680 {
3687 }
3689 /* Identify whether this is a parameter pack or not. */
3691 {
3699 /* FALLTHRU */
3701 /* If the placeholder appears in the decl-specifier-seq of a function
3702 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3703 is a pack expansion, the invented template parameter is a template
3704 parameter pack. */
3714 {
3715 /* We don't want to walk into the type of a PARM_DECL,
3716 because we don't want to see the type parameter pack. */
3719 }
3724 {
3725 /* We don't want to walk into the type of a variadic capture proxy,
3726 because we don't want to see the type parameter pack. */
3729 }
3731 {
3733 find_parameter_packs_r,
3736 }
3748 /* Not a parameter pack. */
3750 }
3753 {
3754 /* Add this parameter pack to the list. */
3756 }
3762 /* This switch statement will return immediately if we don't find a
3763 parameter pack. */
3765 {
3770 /* Check the template itself. */
3773 /* Check the template arguments. */
3787 /* Ignore the declaration of a capture proxy for a parameter pack. */
3795 /* Fall through. */
3840 {
3841 /* Look at explicit captures. */
3846 /* Since we defer implicit capture, look in the body as well. */
3852 }
3855 {
3856 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3857 type_pack_expansion_p to false so that any placeholders
3858 within the expression don't get marked as parameter packs. */
3866 }
3870 }
3873 }
3875 /* Determines if the expression or type T uses any parameter packs. */
3876 bool
3878 {
3887 }
3889 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3890 representation a base-class initializer into a parameter pack
3891 expansion. If all goes well, the resulting node will be an
3892 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3893 respectively. */
3894 tree
3896 {
3897 tree result;
3906 {
3907 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3908 class initializer. In this case, the TREE_PURPOSE will be a
3909 _TYPE node (representing the base class expansion we're
3910 initializing) and the TREE_VALUE will be a TREE_LIST
3911 containing the initialization arguments.
3913 The resulting expansion looks somewhat different from most
3914 expansions. Rather than returning just one _EXPANSION, we
3915 return a TREE_LIST whose TREE_PURPOSE is a
3916 TYPE_PACK_EXPANSION containing the bases that will be
3917 initialized. The TREE_VALUE will be identical to the
3918 original TREE_VALUE, which is a list of arguments that will
3919 be passed to each base. We do not introduce any new pack
3920 expansion nodes into the TREE_VALUE (although it is possible
3921 that some already exist), because the TREE_PURPOSE and
3922 TREE_VALUE all need to be expanded together with the same
3923 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3924 resulting TREE_PURPOSE will mention the parameter packs in
3925 both the bases and the arguments to the bases. */
3926 tree purpose;
3927 tree value;
3930 /* Determine which parameter packs will be used by the base
3931 class expansion. */
3940 {
3943 arg);
3946 }
3949 {
3950 /* Collect the sets of parameter packs used in each of the
3951 initialization arguments. */
3953 {
3954 /* Determine which parameter packs will be expanded in this
3955 argument. */
3958 }
3959 }
3963 /* Create the pack expansion type for the base type. */
3969 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3970 they will rarely be compared to anything. */
3974 }
3979 /* Build the PACK_EXPANSION_* node. */
3980 result = for_types
3985 {
3986 /* Propagate type and const-expression information. */
3989 /* Mark this read now, since the expansion might be length 0. */
3991 }
3992 else
3993 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3994 they will rarely be compared to anything. */
3997 /* Determine which parameter packs will be expanded. */
4004 /* Make sure we found some parameter packs. */
4006 {
4008 {
4011 else
4013 }
4015 }
4021 }
4023 /* Checks T for any "bare" parameter packs, which have not yet been
4024 expanded, and issues an error if any are found. This operation can
4025 only be done on full expressions or types (e.g., an expression
4026 statement, "if" condition, etc.), because we could have expressions like:
4028 foo(f(g(h(args)))...)
4030 where "args" is a parameter pack. check_for_bare_parameter_packs
4031 should not be called for the subexpressions args, h(args),
4032 g(h(args)), or f(g(h(args))), because we would produce erroneous
4033 error messages.
4035 Returns TRUE and emits an error if there were bare parameter packs,
4036 returns FALSE otherwise. */
4037 bool
4039 {
4046 /* A lambda might use a parameter pack from the containing context. */
4061 {
4065 {
4076 else
4081 else
4085 }
4088 }
4091 }
4093 /* Expand any parameter packs that occur in the template arguments in
4094 ARGS. */
4095 tree
4097 {
4106 /* First, determine if we need to expand anything, and the number of
4107 slots we'll need. */
4109 {
4114 {
4118 else
4120 }
4121 else
4122 {
4124 num_result_args++;
4125 }
4126 }
4128 /* If no expansion is necessary, we're done. */
4132 /* Expand arguments. */
4135 non_default_args_count =
4138 {
4141 {
4148 }
4149 else
4150 {
4153 }
4154 }
4158 }
4160 /* Checks if DECL shadows a template parameter.
4162 [temp.local]: A template-parameter shall not be redeclared within its
4163 scope (including nested scopes).
4165 Emits an error and returns TRUE if the DECL shadows a parameter,
4166 returns FALSE otherwise. */
4168 bool
4170 {
4171 tree olddecl;
4173 /* If we're not in a template, we can't possibly shadow a template
4174 parameter. */
4178 /* Figure out what we're shadowing. */
4182 /* If there's no previous binding for this name, we're not shadowing
4183 anything, let alone a template parameter. */
4187 /* If we're not shadowing a template parameter, we're done. Note
4188 that OLDDECL might be an OVERLOAD (or perhaps even an
4189 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4190 node. */
4194 /* We check for decl != olddecl to avoid bogus errors for using a
4195 name inside a class. We check TPFI to avoid duplicate errors for
4196 inline member templates. */
4202 /* Don't complain about the injected class name, as we've already
4203 complained about the class itself. */
4210 else
4215 }
4217 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4218 ORIG_LEVEL, DECL, and TYPE. */
4220 static tree
4224 tree decl,
4225 tree type)
4226 {
4237 }
4239 /* Find the canonical type parameter for the given template type
4240 parameter. Returns the canonical type parameter, which may be TYPE
4241 if no such parameter existed. */
4243 static tree
4245 {
4246 tree list;
4260 else
4261 {
4265 }
4266 }
4268 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4269 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4270 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4271 new one is created. */
4273 static tree
4275 tsubst_flags_t complain)
4276 {
4281 {
4300 /* Template template parameters need this. */
4302 {
4309 }
4310 }
4313 }
4315 /* Process information from new template parameter PARM and append it
4316 to the LIST being built. This new parameter is a non-type
4317 parameter iff IS_NON_TYPE is true. This new parameter is a
4318 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4319 is in PARM_LOC. */
4321 tree
4324 {
4333 {
4337 {
4341 else
4343 }
4346 }
4349 {
4355 {
4356 /* [temp.param]
4358 The top-level cv-qualifiers on the template-parameter are
4359 ignored when determining its type. */
4364 && !is_parameter_pack
4365 /* If we're in a nested template parameter list, the template
4366 template parameter could be a parameter pack. */
4368 {
4369 /* This template parameter is not a parameter pack, but it
4370 should be. Complain about "bare" parameter packs. */
4373 /* Recover by calling this a parameter pack. */
4375 }
4376 }
4378 /* A template parameter is not modifiable. */
4387 processing_template_decl,
4392 }
4393 else
4394 {
4395 tree t;
4399 {
4401 /* This is for distinguishing between real templates and template
4402 template parameters */
4406 }
4407 else
4408 {
4410 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4413 }
4420 processing_template_decl,
4424 }
4428 /* Build requirements for the type/template parameter.
4429 This must be done after SET_DECL_TEMPLATE_PARM_P or
4430 process_template_parm could fail. */
4438 /* Build the parameter node linking the parameter declaration,
4439 its default argument (if any), and its constraints (if any). */
4444 }
4446 /* The end of a template parameter list has been reached. Process the
4447 tree list into a parameter vector, converting each parameter into a more
4448 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4449 as PARM_DECLs. */
4451 tree
4453 {
4458 /* Pop the dummy parameter level and add the real one. */
4461 current_template_parms
4466 {
4470 }
4475 }
4477 // Explicitly indicate the end of the template parameter list. We assume
4478 // that the current template parameters have been constructed and/or
4479 // managed explicitly, as when creating new template template parameters
4480 // from a shorthand constraint.
4481 void
4483 {
4485 }
4487 /* end_template_decl is called after a template declaration is seen. */
4489 void
4491 {
4497 /* This matches the pushlevel in begin_template_parm_list. */
4502 }
4504 /* Takes a TREE_LIST representing a template parameter and convert it
4505 into an argument suitable to be passed to the type substitution
4506 functions. Note that If the TREE_LIST contains an error_mark
4507 node, the returned argument is error_mark_node. */
4509 tree
4511 {
4524 {
4528 {
4529 /* Turn this argument into a TYPE_ARGUMENT_PACK
4530 with a single element, which expands T. */
4539 }
4540 }
4541 else
4542 {
4546 {
4547 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4548 with a single element, which expands T. */
4558 }
4559 else
4561 }
4563 }
4565 /* Given a single level of template parameters (a TREE_VEC), return it
4566 as a set of template arguments. */
4568 static tree
4570 {
4580 }
4582 /* Given a set of template parameters, return them as a set of template
4583 arguments. The template parameters are represented as a TREE_VEC, in
4584 the form documented in cp-tree.h for template arguments. */
4586 static tree
4588 {
4589 tree header;
4594 /* If there is only one level of template parameters, we do not
4595 create a TREE_VEC of TREE_VECs. Instead, we return a single
4596 TREE_VEC containing the arguments. */
4601 {
4606 else
4608 }
4611 }
4613 /* Within the declaration of a template, return the currently active
4614 template parameters as an argument TREE_VEC. */
4616 static tree
4618 {
4620 }
4622 /* Update the declared TYPE by doing any lookups which were thought to be
4623 dependent, but are not now that we know the SCOPE of the declarator. */
4625 tree
4627 {
4638 /* Don't bother building up the args in this case. */
4640 {
4641 /* tsubst in the args corresponding to the template parameters,
4642 including auto if present. Most things will be unchanged, but
4643 make_typename_type and tsubst_qualified_id will resolve
4644 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4647 tree pushed;
4649 {
4653 }
4658 }
4664 {
4667 else
4669 }
4671 }
4673 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4674 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4675 the new template is a member template. */
4677 tree
4679 {
4688 }
4690 struct template_parm_data
4691 {
4692 /* The level of the template parameters we are currently
4693 processing. */
4696 /* The index of the specialization argument we are currently
4697 processing. */
4700 /* An array whose size is the number of template parameters. The
4701 elements are nonzero if the parameter has been used in any one
4702 of the arguments processed so far. */
4705 /* An array whose size is the number of template arguments. The
4706 elements are nonzero if the argument makes use of template
4707 parameters of this level. */
4709 };
4711 /* Subroutine of push_template_decl used to see if each template
4712 parameter in a partial specialization is used in the explicit
4713 argument list. If T is of the LEVEL given in DATA (which is
4714 treated as a template_parm_data*), then DATA->PARMS is marked
4715 appropriately. */
4717 static int
4719 {
4727 {
4730 }
4732 /* In C++17 the type of a non-type argument is a deduced context. */
4737 data,
4738 NULL,
4741 /* Return zero so that for_each_template_parm will continue the
4742 traversal of the tree; we want to mark *every* template parm. */
4744 }
4746 /* Process the partial specialization DECL. */
4748 static tree
4750 {
4757 tree inner_parms;
4758 tree inst;
4768 /* A concept cannot be specialized. */
4770 {
4773 }
4778 /* We check that each of the template parameters given in the
4779 partial specialization is used in the argument list to the
4780 specialization. For example:
4782 template <class T> struct S;
4783 template <class T> struct S<T*>;
4785 The second declaration is OK because `T*' uses the template
4786 parameter T, whereas
4788 template <class T> struct S<int>;
4790 is no good. Even trickier is:
4792 template <class T>
4793 struct S1
4794 {
4795 template <class U>
4796 struct S2;
4797 template <class U>
4798 struct S2<T>;
4799 };
4801 The S2<T> declaration is actually invalid; it is a
4802 full-specialization. Of course,
4804 template <class U>
4805 struct S2<T (*)(U)>;
4807 or some such would have been OK. */
4815 {
4820 NULL,
4822 }
4825 {
4826 /* One of the template parms was not used in a deduced context in the
4827 specialization. */
4829 {
4833 }
4837 }
4842 /* [temp.class.spec]
4844 The argument list of the specialization shall not be identical to
4845 the implicit argument list of the primary template. */
4846 tree main_args
4849 && (!flag_concepts
4852 {
4855 "any template arguments; to define the primary template, "
4857 else
4859 "template arguments and is not more constrained than "
4860 "the primary template; to define the primary template, "
4863 }
4865 /* A partial specialization that replaces multiple parameters of the
4866 primary template with a pack expansion is less specialized for those
4867 parameters. */
4869 {
4871 "primary template because it replaces multiple parameters "
4874 /* Avoid crash in process_partial_specialization. */
4876 }
4878 /* If we aren't in a dependent class, we can actually try deduction. */
4880 /* FIXME we should be able to handle a partial specialization of a
4881 partial instantiation, but currently we can't (c++/41727). */
4884 {
4888 maintmpl);
4889 }
4891 /* [temp.class.spec]
4893 A partially specialized non-type argument expression shall not
4894 involve template parameters of the partial specialization except
4895 when the argument expression is a simple identifier.
4897 The type of a template parameter corresponding to a specialized
4898 non-type argument shall not be dependent on a parameter of the
4899 specialization.
4901 Also, we verify that pack expansions only occur at the
4902 end of the argument list. */
4906 {
4913 {
4914 /* Extract the arguments from the argument pack. We'll be
4915 iterating over these in the following loop. */
4918 }
4921 {
4923 /* Get the Jth argument in the parameter pack. */
4927 {
4928 /* Pack expansions must come at the end of the
4929 argument list. */
4932 {
4936 else
4939 }
4940 }
4943 /* We only care about the pattern. */
4949 /* This next two lines are the `argument expression is not just a
4950 simple identifier' condition and also the `specialized
4951 non-type argument' bit. */
4955 {
4959 arg);
4960 else
4961 {
4962 /* Look at the corresponding template parameter,
4963 marking which template parameters its type depends
4964 upon. */
4968 {
4969 /* We haven't yet initialized TPD2. Do so now. */
4971 /* The number of parameters here is the number in the
4972 main template, which, as checked in the assertion
4973 above, is NARGS. */
4977 }
4979 /* Mark the template parameters. But this time, we're
4980 looking for the template parameters of the main
4981 template, not in the specialization. */
4988 NULL,
4992 {
4993 /* The type depended on some template parameters.
4994 If they are fully specialized in the
4995 specialization, that's OK. */
5004 "type %qT of template argument %qE depends "
5006 "type %qT of template argument %qE depends "
5008 type,
5009 arg);
5010 }
5011 }
5012 }
5013 }
5014 }
5016 /* We should only get here once. */
5020 // Build the template decl.
5029 /* Give template template parms a DECL_CONTEXT of the template
5030 for which they are a parameter. */
5032 {
5036 }
5039 /* We didn't register this in check_explicit_specialization so we could
5040 wait until the constraints were set. */
5042 else
5052 {
5058 {
5066 "declaration of %qD ambiguates earlier template "
5070 "partial specialization of %qD after instantiation "
5072 }
5073 }
5076 }
5078 /* PARM is a template parameter of some form; return the corresponding
5079 TEMPLATE_PARM_INDEX. */
5081 static tree
5083 {
5096 }
5098 /* Subroutine of fixed_parameter_pack_p below. Look for any template
5099 parameter packs used by the template parameter PARM. */
5101 static void
5103 {
5104 /* A type parm can't refer to another parm. */
5108 {
5112 }
5119 }
5121 /* PARM is a template parameter pack. Return any parameter packs used in
5122 its type or the type of any of its template parameters. If there are
5123 any such packs, it will be instantiated into a fixed template parameter
5124 list by partial instantiation rather than be fully deduced. */
5126 tree
5128 {
5129 /* This can only be true in a member template. */
5132 /* This can only be true for a parameter pack. */
5135 /* A type parm can't refer to another parm. */
5149 }
5151 /* Check that a template declaration's use of default arguments and
5152 parameter packs is not invalid. Here, PARMS are the template
5153 parameters. IS_PRIMARY is true if DECL is the thing declared by
5154 a primary template. IS_PARTIAL is true if DECL is a partial
5155 specialization.
5157 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
5158 function template declaration or a friend class template
5159 declaration. In the function case, 1 indicates a declaration, 2
5160 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
5161 emitted for extraneous default arguments.
5163 Returns TRUE if there were no errors found, FALSE otherwise. */
5165 bool
5168 {
5171 tree parm_level;
5174 /* [temp.param]
5176 A default template-argument shall not be specified in a
5177 function template declaration or a function template definition, nor
5178 in the template-parameter-list of the definition of a member of a
5179 class template. */
5183 /* You can't have a function template declaration in a local
5184 scope, nor you can you define a member of a class template in a
5185 local scope. */
5193 /* A lambda doesn't have an explicit declaration; don't complain
5194 about the parms of the enclosing class. */
5201 /* If this is either a friend defined in the scope of the class
5202 or a member function. */
5208 /* And, if it was a member function, it really was defined in
5209 the scope of the class. */
5212 /* We already checked these parameters when the template was
5213 declared, so there's no need to do it again now. This function
5214 was defined in class scope, but we're processing its body now
5215 that the class is complete. */
5218 /* Core issue 226 (C++0x only): the following only applies to class
5219 templates. */
5222 {
5223 /* [temp.param]
5225 If a template-parameter has a default template-argument, all
5226 subsequent template-parameters shall have a default
5227 template-argument supplied. */
5229 {
5236 {
5246 {
5248 /* For better subsequent error-recovery, we indicate that
5249 there should have been a default argument. */
5252 }
5254 && !is_friend_decl
5255 /* Don't complain about an enclosing partial
5256 specialization. */
5261 /* A fixed parameter pack will be partially
5262 instantiated into a fixed length list. */
5264 {
5265 /* A primary class template can only have one
5266 parameter pack, at the end of the template
5267 parameter list. */
5275 }
5276 }
5277 }
5278 }
5281 || is_partial
5282 || !is_primary
5284 /* For an ordinary class template, default template arguments are
5285 allowed at the innermost level, e.g.:
5286 template <class T = int>
5287 struct S {};
5288 but, in a partial specialization, they're not allowed even
5289 there, as we have in [temp.class.spec]:
5291 The template parameter list of a specialization shall not
5292 contain default template argument values.
5294 So, for a partial specialization, or for a function template
5295 (in C++98/C++03), we look at all of them. */
5296 ;
5297 else
5298 /* But, for a primary class template that is not a partial
5299 specialization we look at all template parameters except the
5300 innermost ones. */
5303 /* Figure out what error message to issue. */
5318 else
5319 /* Per [temp.param]/9, "A default template-argument shall not be
5320 specified in the template-parameter-lists of the definition of
5321 a member of a class template that appears outside of the member's
5322 class.", thus if we aren't handling a member of a class template
5323 there is no need to examine the parameters. */
5327 /* If we're inside a class definition, there's no need to
5328 examine the parameters to the class itself. On the one
5329 hand, they will be checked when the class is defined, and,
5330 on the other, default arguments are valid in things like:
5331 template <class T = double>
5332 struct S { template <class U> void f(U); };
5333 Here the default argument for `S' has no bearing on the
5334 declaration of `f'. */
5336 else
5337 /* Check everything. */
5343 {
5350 {
5355 {
5357 {
5364 }
5366 /* Clear out the default argument so that we are not
5367 confused later. */
5369 }
5370 }
5372 /* At this point, if we're still interested in issuing messages,
5373 they must apply to classes surrounding the object declared. */
5377 }
5380 }
5382 /* Worker for push_template_decl_real, called via
5383 for_each_template_parm. DATA is really an int, indicating the
5384 level of the parameters we are interested in. If T is a template
5385 parameter of that level, return nonzero. */
5387 static int
5389 {
5395 else
5398 }
5400 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5401 DATA is really an int, indicating the innermost outer level of parameters.
5402 If T is a template parameter of that level or further out, return
5403 nonzero. */
5405 static int
5407 {
5413 else
5416 }
5418 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5419 parameters given by current_template_args, or reuses a
5420 previously existing one, if appropriate. Returns the DECL, or an
5421 equivalent one, if it is replaced via a call to duplicate_decls.
5423 If IS_FRIEND is true, DECL is a friend declaration. */
5425 tree
5427 {
5428 tree tmpl;
5429 tree args;
5430 tree info;
5431 tree ctx;
5435 /* True if the template is a member template, in the sense of
5436 [temp.mem]. */
5442 /* See if this is a partial specialization. */
5455 /* For a friend, we want the context of the friend, not
5456 the type of which it is a friend. */
5460 /* In the case of a virtual function, we want the class in which
5461 it is defined. */
5463 else
5464 /* Otherwise, if we're currently defining some class, the DECL
5465 is assumed to be a member of the class. */
5474 /* See if this is a primary template. */
5477 /* A friend template that specifies a class context, i.e.
5478 template <typename T> friend void A<T>::f();
5479 is not primary. */
5484 else
5488 {
5495 {
5498 }
5500 {
5502 {
5505 }
5507 {
5508 /* [temp.mem]
5510 A destructor shall not be a member template. */
5513 }
5520 {
5521 /* [basic.stc.dynamic.allocation]
5523 An allocation function can be a function
5524 template. ... Template allocation functions shall
5525 have two or more parameters. */
5528 }
5529 }
5532 {
5533 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5536 {
5542 }
5543 }
5546 /* alias-declaration */
5550 else
5551 {
5554 }
5555 }
5557 /* Check to see that the rules regarding the use of default
5558 arguments are not being violated. We check args for a friend
5559 functions when we know whether it's a definition, introducing
5560 declaration or re-declaration. */
5565 /* Ensure that there are no parameter packs in the type of this
5566 declaration that have not been expanded. */
5568 {
5569 /* Check each of the arguments individually to see if there are
5570 any bare parameter packs. */
5576 {
5579 {
5580 /* This is a PARM_DECL that contains unexpanded parameter
5581 packs. We have already complained about this in the
5582 check_for_bare_parameter_packs call, so just replace
5583 these types with ERROR_MARK_NODE. */
5586 }
5590 }
5592 /* Check for bare parameter packs in the return type and the
5593 exception specifiers. */
5595 /* Errors were already issued, set return type to int
5596 as the frontend doesn't expect error_mark_node as
5597 the return type. */
5601 }
5606 {
5609 }
5622 {
5627 /* If DECL is a TYPE_DECL for a class-template, then there won't
5628 be DECL_LANG_SPECIFIC. The information equivalent to
5629 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5633 {
5634 /* Since a template declaration already existed for this
5635 class-type, we must be redeclaring it here. Make sure
5636 that the redeclaration is valid. */
5638 current_template_parms,
5640 /* We don't need to create a new TEMPLATE_DECL; just use the
5641 one we already had. */
5643 }
5644 else
5645 {
5647 member_template_p);
5652 {
5653 /* A specialization of a member template of a template
5654 class. */
5658 }
5659 }
5660 }
5661 else
5662 {
5668 {
5671 }
5679 {
5680 tree new_tmpl;
5682 /* The declaration is a specialization of a member
5683 template, declared outside the class. Therefore, the
5684 innermost template arguments will be NULL, so we
5685 replace them with the arguments determined by the
5686 earlier call to check_explicit_specialization. */
5689 new_tmpl
5691 member_template_p);
5701 args,
5704 }
5706 /* Make sure the template headers we got make sense. */
5711 {
5716 }
5717 else
5719 {
5724 {
5728 else
5732 /* Avoid crash in import_export_decl. */
5735 }
5740 /* Can happen in erroneous input. */
5742 else
5744 }
5746 /* Check that the parms are used in the appropriate qualifying scopes
5747 in the declarator. */
5751 {
5757 /* Avoid crash in import_export_decl. */
5760 }
5761 }
5766 /* Push template declarations for global functions and types. Note
5767 that we do not try to push a global template friend declared in a
5768 template class; such a thing may well depend on the template
5769 parameters of the class. */
5772 {
5777 /* Hide template friend classes that haven't been declared yet. */
5779 {
5782 }
5783 }
5786 {
5791 /* Give template template parms a DECL_CONTEXT of the template
5792 for which they are a parameter. */
5795 {
5799 }
5805 }
5807 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5808 back to its most general template. If TMPL is a specialization,
5809 ARGS may only have the innermost set of arguments. Add the missing
5810 argument levels if necessary. */
5818 else
5819 {
5824 }
5827 && !is_friend
5830 /* Set DECL_COMDAT on template instantiations; if we force
5831 them to be emitted by explicit instantiation or -frepo,
5832 mark_needed will tell cgraph to do the right thing. */
5836 }
5838 tree
5840 {
5842 }
5844 /* FN is an inheriting constructor that inherits from the constructor
5845 template INHERITED; turn FN into a constructor template with a matching
5846 template header. */
5848 tree
5850 {
5851 tree inner_parms
5854 tree parms
5865 }
5867 /* Called when a class template TYPE is redeclared with the indicated
5868 template PARMS, e.g.:
5870 template <class T> struct S;
5871 template <class T> struct S {}; */
5873 bool
5875 {
5876 tree tmpl;
5877 tree tmpl_parms;
5881 {
5884 }
5888 /* The type is nested in some template class. Nothing to worry
5889 about here; there are no new template parameters for the nested
5890 type. */
5894 {
5896 tmpl);
5898 }
5904 {
5914 }
5917 {
5918 tree tmpl_parm;
5919 tree parm;
5920 tree tmpl_default;
5921 tree parm_default;
5935 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5936 TEMPLATE_DECL. */
5946 {
5950 }
5953 {
5954 /* We have in [temp.param]:
5956 A template-parameter may not be given default arguments
5957 by two different declarations in the same scope. */
5962 }
5965 /* Update the previous template parameters (which are the ones
5966 that will really count) with the new default value. */
5969 /* Update the new parameters, too; they'll be used as the
5970 parameters for any members. */
5973 /* Give each template template parm in this redeclaration a
5974 DECL_CONTEXT of the template for which they are a parameter. */
5976 {
5979 }
5983 }
5985 // Cannot redeclare a class template with a different set of constraints.
5987 {
5992 }
5995 }
5997 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5998 to be used when the caller has already checked
5999 (processing_template_decl
6000 && !instantiation_dependent_expression_p (expr)
6001 && potential_constant_expression (expr))
6002 and cleared processing_template_decl. */
6004 tree
6006 {
6009 complain,
6013 }
6015 /* Simplify EXPR if it is a non-dependent expression. Returns the
6016 (possibly simplified) expression. */
6018 tree
6020 {
6024 /* If we're in a template, but EXPR isn't value dependent, simplify
6025 it. We're supposed to treat:
6027 template <typename T> void f(T[1 + 1]);
6028 template <typename T> void f(T[2]);
6030 as two declarations of the same function, for example. */
6033 {
6034 processing_template_decl_sentinel s;
6036 }
6038 }
6040 tree
6042 {
6044 }
6046 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
6047 an uninstantiated expression. */
6049 tree
6051 {
6055 {
6058 else
6059 {
6060 processing_template_decl_sentinel s;
6062 }
6063 }
6065 }
6067 /* True iff T is a specialization of a variable template. */
6069 bool
6071 {
6076 }
6078 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
6079 template declaration, or a TYPE_DECL for an alias declaration. */
6081 bool
6083 {
6091 }
6093 /* Return TRUE iff T is a specialization of an alias template. */
6095 bool
6097 {
6098 /* It's an alias template specialization if it's an alias and its
6099 TYPE_NAME is a specialization of a primary template. */
6105 }
6107 /* An alias template is complex from a SFINAE perspective if a template-id
6108 using that alias can be ill-formed when the expansion is not, as with
6109 the void_t template. We determine this by checking whether the
6110 expansion for the alias template uses all its template parameters. */
6112 struct uses_all_template_parms_data
6113 {
6116 };
6118 static int
6120 {
6128 }
6130 static bool
6132 {
6147 }
6149 /* Return TRUE iff T is a specialization of a complex alias template with
6150 dependent template-arguments. */
6152 bool
6154 {
6167 }
6169 /* Return the number of innermost template parameters in TMPL. */
6171 static int
6173 {
6176 }
6178 /* Return either TMPL or another template that it is equivalent to under DR
6179 1286: An alias that just changes the name of a template is equivalent to
6180 the other template. */
6182 static tree
6184 {
6187 {
6188 /* Determine if the alias is equivalent to an underlying template. */
6200 tree alias_args = INNERMOST_TEMPLATE_ARGS
6205 /* Alias is equivalent. Strip it and repeat. */
6207 }
6210 }
6212 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6213 must be a reference-to-function or a pointer-to-function type, as specified
6214 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6215 and check that the resulting function has external linkage. */
6217 static tree
6219 tsubst_flags_t complain)
6220 {
6223 linkage_kind linkage;
6238 /* [temp.arg.nontype]/1
6240 A template-argument for a non-type, non-template template-parameter
6241 shall be one of:
6242 [...]
6243 -- the address of an object or function with external [C++11: or
6244 internal] linkage. */
6247 {
6249 {
6255 else
6258 }
6260 }
6264 {
6266 {
6271 else
6275 }
6277 }
6279 accept:
6281 {
6284 else
6286 }
6291 }
6293 /* Subroutine of convert_nontype_argument.
6294 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6295 Emit an error otherwise. */
6297 static bool
6299 tsubst_flags_t complain)
6300 {
6317 {
6322 else
6324 }
6326 }
6328 /* Returns TRUE iff the address of OP is value-dependent.
6330 14.6.2.4 [temp.dep.temp]:
6331 A non-integral non-type template-argument is dependent if its type is
6332 dependent or it has either of the following forms
6333 qualified-id
6334 & qualified-id
6335 and contains a nested-name-specifier which specifies a class-name that
6336 names a dependent type.
6338 We generalize this to just say that the address of a member of a
6339 dependent class is value-dependent; the above doesn't cover the
6340 address of a static data member named with an unqualified-id. */
6342 static bool
6344 {
6345 /* We could use get_inner_reference here, but there's no need;
6346 this is only relevant for template non-type arguments, which
6347 can only be expressed as &id-expression. */
6349 {
6353 }
6356 }
6358 /* The next set of functions are used for providing helpful explanatory
6359 diagnostics for failed overload resolution. Their messages should be
6360 indented by two spaces for consistency with the messages in
6361 call.c */
6363 static int
6365 {
6367 }
6369 /* Other failure functions should call this one, to provide a single function
6370 for setting a breakpoint on. */
6372 static int
6374 {
6376 }
6378 static int
6380 {
6385 }
6387 static int
6389 {
6395 }
6397 static int
6399 {
6403 }
6405 static int
6407 {
6410 " template parameter %qD is not a parameter pack, but "
6414 }
6416 static int
6418 {
6421 " template argument %qE does not match "
6425 }
6427 static int
6429 {
6433 }
6435 static int
6437 {
6443 }
6445 static int
6447 {
6449 {
6454 else
6456 " deduced conflicting values for non-type parameter "
6458 }
6460 }
6462 static int
6464 {
6467 " variable-sized array type %qT is not "
6469 arg);
6471 }
6473 static int
6475 {
6479 arg);
6481 }
6483 static int
6485 {
6487 {
6493 else
6498 }
6500 }
6502 static int
6504 {
6506 }
6508 static int
6511 {
6513 }
6515 static int
6518 {
6524 }
6526 static int
6529 {
6532 {
6540 }
6542 }
6544 static int
6546 {
6549 " template parameters of a template template argument are "
6552 }
6554 static int
6556 {
6562 }
6564 static int
6566 {
6571 }
6573 /* Attempt to convert the non-type template parameter EXPR to the
6574 indicated TYPE. If the conversion is successful, return the
6575 converted value. If the conversion is unsuccessful, return
6576 NULL_TREE if we issued an error message, or error_mark_node if we
6577 did not. We issue error messages for out-and-out bad template
6578 parameters, but not simply because the conversion failed, since we
6579 might be just trying to do argument deduction. Both TYPE and EXPR
6580 must be non-dependent.
6582 The conversion follows the special rules described in
6583 [temp.arg.nontype], and it is much more strict than an implicit
6584 conversion.
6586 This function is called twice for each template argument (see
6587 lookup_template_class for a more accurate description of this
6588 problem). This means that we need to handle expressions which
6589 are not valid in a C++ source, but can be created from the
6590 first call (for instance, casts to perform conversions). These
6591 hacks can go away after we fix the double coercion problem. */
6593 static tree
6595 {
6596 tree expr_type;
6600 /* Detect immediately string literals as invalid non-type argument.
6601 This special-case is not needed for correctness (we would easily
6602 catch this later), but only to provide better diagnostic for this
6603 common user mistake. As suggested by DR 100, we do not mention
6604 linkage issues in the diagnostic as this is not the point. */
6605 /* FIXME we're making this OK. */
6607 {
6613 }
6615 /* Add the ADDR_EXPR now for the benefit of
6616 value_dependent_expression_p. */
6619 {
6623 }
6625 /* If we are in a template, EXPR may be non-dependent, but still
6626 have a syntactic, rather than semantic, form. For example, EXPR
6627 might be a SCOPE_REF, rather than the VAR_DECL to which the
6628 SCOPE_REF refers. Preserving the qualifying scope is necessary
6629 so that access checking can be performed when the template is
6630 instantiated -- but here we need the resolved form so that we can
6631 convert the argument. */
6643 /* If the argument is non-dependent, perform any conversions in
6644 non-dependent context as well. */
6652 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6653 to a non-type argument of "nullptr". */
6657 /* In C++11, integral or enumeration non-type template arguments can be
6658 arbitrary constant expressions. Pointer and pointer to
6659 member arguments can be general constant expressions that evaluate
6660 to a null value, but otherwise still need to be of a specific form. */
6662 {
6664 /* A PTRMEM_CST is already constant, and a valid template
6665 argument for a parameter of pointer to member type, we just want
6666 to leave it in that form rather than lower it to a
6670 {
6671 /* C++17: A template-argument for a non-type template-parameter shall
6672 be a converted constant expression (8.20) of the type of the
6673 template-parameter. */
6679 }
6681 {
6686 }
6687 }
6691 else
6694 /* HACK: Due to double coercion, we can get a
6695 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6696 which is the tree that we built on the first call (see
6697 below when coercing to reference to object or to reference to
6698 function). We just strip everything and get to the arg.
6699 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6700 for examples. */
6702 {
6708 {
6709 /* ??? Maybe we could use convert_from_reference here, but we
6710 would need to relax its constraints because the NOP_EXPR
6711 could actually change the type to something more cv-qualified,
6712 and this is not folded by convert_from_reference. */
6717 && (same_type_ignoring_top_level_qualifiers_p
6720 {
6723 }
6724 }
6725 }
6727 /* [temp.arg.nontype]/5, bullet 1
6729 For a non-type template-parameter of integral or enumeration type,
6730 integral promotions (_conv.prom_) and integral conversions
6731 (_conv.integral_) are applied. */
6733 {
6735 {
6740 }
6745 /* Notice that there are constant expressions like '4 % 0' which
6746 do not fold into integer constants. */
6749 {
6751 {
6755 else
6761 /* else cxx_constant_value complained but gave us
6762 a real constant, so go ahead. */
6764 {
6765 /* Some assemble time constant expressions like
6766 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
6767 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
6768 as we can emit them into .rodata initializers of
6769 variables, yet they can't fold into an INTEGER_CST at
6770 compile time. Refuse them here. */
6775 }
6776 }
6777 else
6779 }
6781 /* Avoid typedef problems. */
6784 }
6785 /* [temp.arg.nontype]/5, bullet 2
6787 For a non-type template-parameter of type pointer to object,
6788 qualification conversions (_conv.qual_) and the array-to-pointer
6789 conversion (_conv.array_) are applied. */
6791 {
6794 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
6795 decay_conversion or an explicit cast. If it's a problematic cast,
6796 we'll complain about it below. */
6798 {
6803 {
6806 }
6807 }
6809 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6811 A template-argument for a non-type, non-template template-parameter
6812 shall be one of: [...]
6814 -- the name of a non-type template-parameter;
6815 -- the address of an object or function with external linkage, [...]
6816 expressed as "& id-expression" where the & is optional if the name
6817 refers to a function or array, or if the corresponding
6818 template-parameter is a reference.
6820 Here, we do not care about functions, as they are invalid anyway
6821 for a parameter of type pointer-to-object. */
6824 /* Non-type template parameters are OK. */
6825 ;
6829 {
6831 {
6834 "because %qD is a variable, not the address of "
6837 }
6839 {
6845 }
6846 /* Other values, like integer constants, might be valid
6847 non-type arguments of some other type. */
6849 }
6850 else
6851 {
6855 {
6860 }
6862 {
6868 }
6871 {
6876 }
6877 /* C++17: For a non-type template-parameter of reference or pointer
6878 type, the value of the constant expression shall not refer to (or
6879 for a pointer type, shall not be the address of):
6880 * a subobject (4.5),
6881 * a temporary object (15.2),
6882 * a string literal (5.13.5),
6883 * the result of a typeid expression (8.2.8), or
6884 * a predefined __func__ variable (11.4.1). */
6886 {
6889 decl);
6891 }
6895 {
6900 }
6902 {
6906 decl);
6908 }
6909 }
6916 }
6917 /* [temp.arg.nontype]/5, bullet 3
6919 For a non-type template-parameter of type reference to object, no
6920 conversions apply. The type referred to by the reference may be more
6921 cv-qualified than the (otherwise identical) type of the
6922 template-argument. The template-parameter is bound directly to the
6923 template-argument, which must be an lvalue. */
6925 {
6927 expr_type))
6931 {
6936 }
6939 {
6944 }
6946 /* [temp.arg.nontype]/1
6948 A template-argument for a non-type, non-template template-parameter
6949 shall be one of: [...]
6951 -- the address of an object or function with external linkage. */
6954 {
6957 {
6960 "because a reference variable does not have a constant "
6963 }
6964 }
6968 /* OK, dependent reference. We don't want to ask whether a DECL is
6970 else
6971 {
6973 {
6979 }
6981 /* DR 1155 allows internal linkage in C++11 and up. */
6984 {
6990 }
6993 }
6997 }
6998 /* [temp.arg.nontype]/5, bullet 4
7000 For a non-type template-parameter of type pointer to function, only
7001 the function-to-pointer conversion (_conv.func_) is applied. If the
7002 template-argument represents a set of overloaded functions (or a
7003 pointer to such), the matching function is selected from the set
7004 (_over.over_). */
7006 {
7007 /* If the argument is a template-id, we might not have enough
7008 context information to decay the pointer. */
7010 {
7014 }
7017 /* Null pointer values are OK in C++11. */
7023 }
7024 /* [temp.arg.nontype]/5, bullet 5
7026 For a non-type template-parameter of type reference to function, no
7027 conversions apply. If the template-argument represents a set of
7028 overloaded functions, the matching function is selected from the set
7029 (_over.over_). */
7031 {
7033 {
7035 {
7040 }
7042 }
7047 }
7048 /* [temp.arg.nontype]/5, bullet 6
7050 For a non-type template-parameter of type pointer to member function,
7051 no conversions apply. If the template-argument represents a set of
7052 overloaded member functions, the matching member function is selected
7053 from the set (_over.over_). */
7055 {
7060 /* [temp.arg.nontype] bullet 1 says the pointer to member
7061 expression must be a pointer-to-member constant. */
7066 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
7067 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
7070 }
7071 /* [temp.arg.nontype]/5, bullet 7
7073 For a non-type template-parameter of type pointer to data member,
7074 qualification conversions (_conv.qual_) are applied. */
7076 {
7077 /* [temp.arg.nontype] bullet 1 says the pointer to member
7078 expression must be a pointer-to-member constant. */
7086 }
7088 {
7090 {
7095 }
7097 }
7098 /* A template non-type parameter must be one of the above. */
7099 else
7102 /* Sanity check: did we actually convert the argument to the
7103 right type? */
7107 }
7109 /* Subroutine of coerce_template_template_parms, which returns 1 if
7110 PARM_PARM and ARG_PARM match using the rule for the template
7111 parameters of template template parameters. Both PARM and ARG are
7112 template parameters; the rest of the arguments are the same as for
7113 coerce_template_template_parms.
7114 */
7115 static int
7117 tree arg,
7118 tsubst_flags_t complain,
7119 tree in_decl,
7120 tree outer_args)
7121 {
7130 {
7132 /* We encounter instantiations of templates like
7133 template <template <template <class> class> class TT>
7134 class C; */
7135 {
7142 }
7143 /* Fall through. */
7148 /* Argument is a parameter pack but parameter is not. */
7153 /* The tsubst call is used to handle cases such as
7155 template <int> class C {};
7156 template <class T, template <T> class TT> class D {};
7157 D<int, C> d;
7159 i.e. the parameter list of TT depends on earlier parameters. */
7161 {
7166 }
7170 /* Argument is a parameter pack but parameter is not. */
7177 }
7180 }
7182 /* Coerce template argument list ARGLIST for use with template
7183 template-parameter TEMPL. */
7185 static tree
7187 tsubst_flags_t complain)
7188 {
7189 /* Consider an example where a template template parameter declared as
7191 template <class T, class U = std::allocator<T> > class TT
7193 The template parameter level of T and U are one level larger than
7194 of TT. To proper process the default argument of U, say when an
7195 instantiation `TT<int>' is seen, we need to build the full
7196 arguments containing {int} as the innermost level. Outer levels,
7197 available when not appearing as default template argument, can be
7198 obtained from the arguments of the enclosing template.
7200 Suppose that TT is later substituted with std::vector. The above
7201 instantiation is `TT<int, std::allocator<T> >' with TT at
7202 level 1, and T at level 2, while the template arguments at level 1
7203 becomes {std::vector} and the inner level 2 is {int}. */
7207 {
7209 /* We want arguments for the partial specialization, not arguments for
7210 the primary template. */
7212 else
7214 }
7216 {
7217 /* This is an argument of the current template, so we haven't set
7218 DECL_CONTEXT yet. */
7219 tree relevant_template_parms;
7221 /* Parameter levels that are greater than the level of the given
7222 template template parm are irrelevant. */
7229 }
7236 complain,
7239 }
7241 /* A cache of template template parameters with match-all default
7242 arguments. */
7244 static void
7246 {
7250 }
7251 static tree
7253 {
7258 }
7260 /* T is a bound template template-parameter. Copy its arguments into default
7261 arguments of the template template-parameter's template parameters. */
7263 static tree
7265 {
7288 {
7291 {
7294 }
7295 }
7299 }
7301 /* ARG is a bound potential template template-argument, and PARGS is a list
7302 of arguments for the corresponding template template-parameter. Adjust
7303 PARGS as appropriate for application to ARG's template, and if ARG is a
7304 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7305 arguments to the template template parameter. */
7307 static tree
7309 {
7313 {
7314 /* When comparing two template template-parameters in partial ordering,
7315 rewrite the one currently being used as an argument to have default
7316 arguments for all parameters. */
7322 }
7323 else
7324 {
7325 tree aparms
7330 }
7333 }
7335 /* Subroutine of unify for the case when PARM is a
7336 BOUND_TEMPLATE_TEMPLATE_PARM. */
7338 static int
7341 {
7345 /* The template template parm might be variadic and the argument
7346 not, so flatten both argument lists. */
7351 {
7352 /* In keeping with P0522R0, adjust P's template arguments
7353 to apply to A's template; then flatten it again. */
7362 /* If the P0522 adjustment eliminated a pack expansion, deduce
7363 empty packs. */
7369 }
7370 else
7371 {
7372 /* Deduce arguments T, i from TT<T> or TT<i>.
7373 We check each element of PARMVEC and ARGVEC individually
7374 rather than the whole TREE_VEC since they can have
7375 different number of elements, which is allowed under N2555. */
7379 /* Check if the parameters end in a pack, making them
7380 variadic. */
7387 /* If the template argument list of P contains a pack
7388 expansion that is not the last template argument, the
7389 entire template argument list is a non-deduced
7390 context. */
7408 DEDUCE_EXACT,
7411 }
7414 }
7416 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7417 template template parameters. Both PARM_PARMS and ARG_PARMS are
7418 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7419 or PARM_DECL.
7421 Consider the example:
7422 template <class T> class A;
7423 template<template <class U> class TT> class B;
7425 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7426 the parameters to A, and OUTER_ARGS contains A. */
7428 static int
7430 tree arg_parms,
7431 tsubst_flags_t complain,
7432 tree in_decl,
7433 tree outer_args)
7434 {
7446 {
7447 /* P0522R0: A template template-parameter P is at least as specialized as
7448 a template template-argument A if, given the following rewrite to two
7449 function templates, the function template corresponding to P is at
7450 least as specialized as the function template corresponding to A
7451 according to the partial ordering rules for function templates
7452 ([temp.func.order]). Given an invented class template X with the
7453 template parameter list of A (including default arguments):
7455 * Each of the two function templates has the same template parameters,
7456 respectively, as P or A.
7458 * Each function template has a single function parameter whose type is
7459 a specialization of X with template arguments corresponding to the
7460 template parameters from the respective function template where, for
7461 each template parameter PP in the template parameter list of the
7462 function template, a corresponding template argument AA is formed. If
7463 PP declares a parameter pack, then AA is the pack expansion
7464 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7466 If the rewrite produces an invalid type, then P is not at least as
7467 specialized as A. */
7469 /* So coerce P's args to apply to A's parms, and then deduce between A's
7470 args and the converted args. If that succeeds, A is at least as
7471 specialized as P, so they match.*/
7478 {
7484 }
7485 }
7487 /* Determine whether we have a parameter pack at the end of the
7488 template template parameter's template parameter list. */
7490 {
7497 {
7511 }
7512 }
7518 /* Check all of the template parameters except the parameter pack at
7519 the end (if any). */
7521 {
7530 outer_args))
7533 }
7536 {
7537 /* Check each of the template parameters in the template
7538 argument against the template parameter pack at the end of
7539 the template template parameter. */
7546 {
7553 outer_args))
7555 }
7556 }
7559 }
7561 /* Verifies that the deduced template arguments (in TARGS) for the
7562 template template parameters (in TPARMS) represent valid bindings,
7563 by comparing the template parameter list of each template argument
7564 to the template parameter list of its corresponding template
7565 template parameter, in accordance with DR150. This
7566 routine can only be called after all template arguments have been
7567 deduced. It will return TRUE if all of the template template
7568 parameter bindings are okay, FALSE otherwise. */
7569 bool
7571 {
7575 /* We're dealing with template parms in this process. */
7581 {
7586 {
7591 {
7592 /* Look inside the argument pack. */
7595 }
7598 {
7602 /* Extract the next argument from the argument
7603 pack. */
7607 /* Look at the pattern of the pack expansion. */
7610 /* Extract the template parameters from the template
7611 argument. */
7617 /* Verify that we can coerce the template template
7618 parameters from the template argument to the template
7619 parameter. This requires an exact match. */
7621 && !coerce_template_template_parms
7623 targ_parms,
7624 tf_none,
7625 tparm,
7626 targs))
7627 {
7630 }
7631 }
7632 }
7633 }
7635 out:
7639 }
7641 /* Since type attributes aren't mangled, we need to strip them from
7642 template type arguments. */
7644 static tree
7646 {
7656 }
7658 /* And from inside dependent non-type arguments like sizeof(Type). */
7660 static tree
7662 {
7672 }
7674 // A template declaration can be substituted for a constrained
7675 // template template parameter only when the argument is more
7676 // constrained than the parameter.
7677 static bool
7679 {
7682 /* For now, allow constrained template template arguments
7683 and unconstrained template template parameters. */
7689 // If the template parameter is constrained, we need to rewrite its
7690 // constraints in terms of the ARG's template parameters. This ensures
7691 // that all of the template parameter types will have the same depth.
7692 //
7693 // Note that this is only valid when coerce_template_template_parm is
7694 // true for the innermost template parameters of PARM and ARG. In other
7695 // words, because coercion is successful, this conversion will be valid.
7697 {
7704 }
7707 }
7709 // Convert a placeholder argument into a binding to the original
7710 // parameter. The original parameter is saved as the TREE_TYPE of
7711 // ARG.
7714 {
7717 }
7719 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
7720 because one of them is dependent. But we need to represent the
7721 conversion for the benefit of cp_tree_equal. */
7723 static tree
7725 {
7726 /* Auto parms get no conversion. */
7729 /* We don't need or want to add this conversion now if we're going to use the
7730 argument for deduction. */
7742 }
7744 /* Convert the indicated template ARG as necessary to match the
7745 indicated template PARM. Returns the converted ARG, or
7746 error_mark_node if the conversion was unsuccessful. Error and
7747 warning messages are issued under control of COMPLAIN. This
7748 conversion is for the Ith parameter in the parameter list. ARGS is
7749 the full set of template arguments deduced so far. */
7751 static tree
7753 tree arg,
7754 tree args,
7755 tsubst_flags_t complain,
7757 tree in_decl)
7758 {
7759 tree orig_arg;
7760 tree val;
7766 /* Trivially convert placeholders. */
7775 {
7776 /* The template argument was the name of some
7777 member function. That's usually
7778 invalid, but static members are OK. In any
7779 case, grab the underlying fields/functions
7780 and issue an error later if required. */
7783 }
7791 /* When determining whether an argument pack expansion is a template,
7792 look at the pattern. */
7796 /* Deal with an injected-class-name used as a template template arg. */
7798 {
7801 {
7811 }
7812 }
7814 is_tmpl_type =
7830 {
7832 {
7836 }
7839 "to refer to a type member of a template parameter, "
7844 typename_type,
7845 complain);
7848 }
7850 {
7852 {
7854 {
7866 else
7869 }
7870 }
7872 }
7874 {
7876 {
7883 else
7886 }
7888 }
7891 /* We already did the appropriate conversion when packing args. */
7894 {
7896 {
7898 /* The number of argument required is not known yet.
7899 Just accept it for now. */
7901 else
7902 {
7904 tree argparm;
7906 /* Strip alias templates that are equivalent to another
7907 template. */
7913 args))
7914 {
7917 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7918 TEMPLATE_DECL. */
7920 {
7925 }
7926 }
7927 else
7928 {
7930 {
7937 }
7940 }
7942 // Check that the constraints are compatible before allowing the
7943 // substitution.
7946 {
7948 {
7954 }
7956 }
7957 }
7958 }
7959 else
7961 /* We only form one instance of each template specialization.
7962 Therefore, if we use a non-canonical variant (i.e., a
7963 typedef), any future messages referring to the type will use
7964 the typedef, which is confusing if those future uses do not
7965 themselves also use the typedef. */
7968 }
7969 else
7970 {
7975 /* We don't have enough levels of args to do any substitution. This
7978 {
7982 }
7983 else
7991 /* We used to call digest_init here. However, digest_init
7992 will report errors, which we don't want when complain
7993 is zero. More importantly, digest_init will try too
7994 hard to convert things: for example, `0' should not be
7995 converted to pointer type at this point according to
7996 the standard. Accepting this is not merely an
7997 extension, since deciding whether or not these
7998 conversions can occur is part of determining which
7999 function template to call, or whether a given explicit
8000 argument specification is valid. */
8002 else
8003 {
8006 }
8016 {
8017 /* Reject template arguments that are references to built-in
8018 functions with no library fallbacks. */
8027 }
8030 {
8031 /* Strip typedefs from the SCOPE_REF. */
8034 complain);
8037 }
8038 }
8041 }
8043 /* Coerces the remaining template arguments in INNER_ARGS (from
8044 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
8045 Returns the coerced argument pack. PARM_IDX is the position of this
8046 parameter in the template parameter list. ARGS is the original
8047 template argument list. */
8048 static tree
8051 tree args,
8052 tree inner_args,
8054 tree new_args,
8056 tree in_decl,
8057 tsubst_flags_t complain)
8058 {
8061 tree packed_args;
8062 tree argument_pack;
8069 {
8070 /* When the template parameter is a non-type template parameter pack
8071 or template template parameter pack whose type or template
8072 parameters use parameter packs, we know exactly how many arguments
8073 we are looking for. Build a vector of the instantiated decls for
8074 these template parameters in PACKED_PARMS. */
8075 /* We can't use make_pack_expansion here because it would interpret a
8076 _DECL as a use rather than a declaration. */
8090 /* If we're doing a partial instantiation of a member template,
8091 verify that all of the types used for the non-type
8092 template parameter pack are, in fact, valid for non-type
8093 template parameters. */
8096 {
8099 {
8103 }
8104 /* We don't know how many args we have yet, just
8105 use the unconverted ones for now. */
8107 }
8110 }
8111 /* Check if we have a placeholder pack, which indicates we're
8112 in the context of a introduction list. In that case we want
8113 to match this pack to the single placeholder. */
8117 {
8120 }
8121 else
8124 /* Convert the remaining arguments, which will be a part of the
8125 parameter pack "parm". */
8128 {
8134 {
8135 /* Once we've packed as many args as we have types, stop. */
8139 /* We don't know how many args we have yet, just
8140 use the unconverted ones for now. */
8142 else
8144 }
8147 {
8150 }
8151 else
8154 in_decl);
8158 }
8162 {
8167 }
8172 else
8173 {
8176 }
8183 }
8185 /* Returns the number of pack expansions in the template argument vector
8186 ARGS. */
8188 static int
8190 {
8195 {
8199 }
8201 }
8203 /* Convert all template arguments to their appropriate types, and
8204 return a vector containing the innermost resulting template
8205 arguments. If any error occurs, return error_mark_node. Error and
8206 warning messages are issued under control of COMPLAIN.
8208 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8209 for arguments not specified in ARGS. Otherwise, if
8210 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
8211 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
8212 USE_DEFAULT_ARGS is false, then all arguments must be specified in
8213 ARGS. */
8215 static tree
8217 tree args,
8218 tree in_decl,
8219 tsubst_flags_t complain,
8222 {
8224 tree orig_inner_args;
8225 tree inner_args;
8226 tree new_args;
8227 tree new_inner_args;
8231 /* When used as a boolean value, indicates whether this is a
8232 variadic template parameter list. Since it's an int, we can also
8233 subtract it from nparms to get the number of non-variadic
8234 parameters. */
8239 /* Adjustment to nparms for fixed parameter packs. */
8244 /* Likewise for parameters with default arguments. */
8252 /* Determine if there are any parameter packs or default arguments. */
8254 {
8262 }
8265 /* If there are no parameters that follow a parameter pack, we need to
8266 expand any argument packs so that we can deduce a parameter pack from
8267 some non-packed args followed by an argument pack, as in variadic85.C.
8268 If there are such parameters, we need to leave argument packs intact
8269 so the arguments are assigned properly. This can happen when dealing
8270 with a nested class inside a partial specialization of a class
8271 template, as in variadic92.C, or when deducing a template parameter pack
8272 from a sub-declarator, as in variadic114.C. */
8276 /* Count any pack expansion args. */
8282 && require_all_args
8283 && !variadic_args_p
8284 && (!use_default_args
8287 {
8288 bad_nargs:
8290 {
8292 {
8296 }
8297 else
8304 }
8307 }
8308 /* We can't pass a pack expansion to a non-pack parameter of an alias
8309 template (DR 1430). */
8313 && variadic_args_p
8315 {
8317 {
8319 {
8325 {
8328 "pack expansion argument for non-pack parameter "
8330 else
8332 "pack expansion argument for non-pack parameter "
8336 }
8337 }
8339 found:;
8340 }
8342 }
8344 /* We need to evaluate the template arguments, even though this
8345 template-id may be nested within a "sizeof". */
8354 {
8355 tree arg;
8356 tree parm;
8358 /* Get the Ith template parameter. */
8362 {
8365 }
8367 /* Calculate the next argument. */
8370 else
8375 {
8376 /* Some arguments will be placed in the
8377 template parameter pack PARM. */
8384 {
8385 /* We don't know how many args we have yet, just use the
8386 unconverted (and still packed) ones for now. */
8390 }
8394 /* Store this argument. */
8396 {
8397 lost++;
8398 /* We are done with all of the arguments. */
8401 }
8402 else
8403 {
8407 {
8410 }
8411 }
8414 }
8416 {
8418 {
8419 /* "If every valid specialization of a variadic template
8420 requires an empty template parameter pack, the template is
8421 ill-formed, no diagnostic required." So check that the
8422 pattern works with this parameter. */
8427 in_decl);
8429 {
8434 }
8436 /* Recover from missing typename. */
8440 /* We don't know how many args we have yet, just
8441 use the unconverted ones for now. */
8445 }
8446 }
8448 {
8449 /* There must be a default arg in this case. */
8452 /* The position of the first default template argument,
8453 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8454 Record that. */
8458 }
8459 else
8463 {
8466 }
8468 {
8469 /* This can occur if there was an error in the template
8470 parameter list itself (which we would already have
8471 reported) that we are trying to recover from, e.g., a class
8472 template with a parameter list such as
8473 template<typename..., typename> (cpp0x/variadic150.C). */
8476 /* This can also happen with a fixed parameter pack (71834). */
8479 }
8480 else
8486 lost++;
8488 }
8493 {
8494 /* If we had fixed parameter packs, we didn't know how many arguments we
8495 actually needed earlier; now we do. */
8499 }
8502 {
8503 /* We had some pack expansion arguments that will only work if the packs
8504 are empty, but wait until instantiation time to complain.
8505 See variadic-ttp3.C. */
8515 }
8518 {
8521 }
8528 }
8530 /* Convert all template arguments to their appropriate types, and
8531 return a vector containing the innermost resulting template
8532 arguments. If any error occurs, return error_mark_node. Error and
8533 warning messages are not issued.
8535 Note that no function argument deduction is performed, and default
8536 arguments are used to fill in unspecified arguments. */
8537 tree
8539 {
8541 }
8543 /* Convert all template arguments to their appropriate type, and
8544 instantiate default arguments as needed. This returns a vector
8545 containing the innermost resulting template arguments, or
8546 error_mark_node if unsuccessful. */
8547 tree
8549 tsubst_flags_t complain)
8550 {
8552 }
8554 /* Like coerce_template_parms. If PARMS represents all template
8555 parameters levels, this function returns a vector of vectors
8556 representing all the resulting argument levels. Note that in this
8557 case, only the innermost arguments are coerced because the
8558 outermost ones are supposed to have been coerced already.
8560 Otherwise, if PARMS represents only (the innermost) vector of
8561 parameters, this function returns a vector containing just the
8562 innermost resulting arguments. */
8564 static tree
8566 tree args,
8567 tree in_decl,
8568 tsubst_flags_t complain,
8571 {
8574 tree coerced_args;
8577 {
8579 tree level;
8585 {
8586 tree l;
8590 require_all_args,
8591 use_default_args);
8592 else
8599 }
8600 }
8601 else
8604 require_all_args,
8605 use_default_args);
8607 }
8609 /* Returns 1 if template args OT and NT are equivalent. */
8611 int
8613 {
8622 /* For member templates */
8631 {
8648 }
8652 {
8655 /* Don't treat an alias template specialization with dependent
8656 arguments as equivalent to its underlying type when used as a
8657 template argument; we need them to be distinct so that we
8658 substitute into the specialization arguments at instantiation
8659 time. And aliases can't be equivalent without being ==, so
8660 we don't need to look any deeper.
8662 During partial ordering, however, we need to treat them normally so
8663 that we can order uses of the same alias with different
8664 cv-qualification (79960). */
8668 else
8670 }
8673 else
8674 {
8675 /* Try to treat a template non-type argument that has been converted
8676 to the parameter type as equivalent to one that hasn't yet. */
8689 }
8690 }
8692 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8693 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8694 NEWARG_PTR with the offending arguments if they are non-NULL. */
8696 int
8700 {
8713 {
8718 {
8724 }
8725 }
8727 }
8731 {
8733 }
8735 /* Implement a freelist interface for objects of type T.
8737 Head is a separate object, rather than a regular member, so that we
8738 can define it as a GTY deletable pointer, which is highly
8739 desirable. A data member could be declared that way, but then the
8740 containing object would implicitly get GTY((user)), which would
8741 prevent us from instantiating freelists as global objects.
8742 Although this way we can create freelist global objects, they're
8743 such thin wrappers that instantiating temporaries at every use
8744 loses nothing and saves permanent storage for the freelist object.
8746 Member functions next, anew, poison and reinit have default
8747 implementations that work for most of the types we're interested
8748 in, but if they don't work for some type, they should be explicitly
8749 specialized. See the comments before them for requirements, and
8750 the example specializations for the tree_list_freelist. */
8752 class freelist
8753 {
8754 /* Return the next object in a chain. We could just do type
8755 punning, but if we access the object with its underlying type, we
8756 avoid strict-aliasing trouble. This needs only work between
8757 poison and reinit. */
8760 /* Return a newly allocated, uninitialized or minimally-initialized
8761 object of type T. Any initialization performed by anew should
8762 either remain across the life of the object and the execution of
8763 poison, or be redone by reinit. */
8766 /* Optionally scribble all over the bits holding the object, so that
8767 they become (mostly?) uninitialized memory. This is called while
8768 preparing to make the object part of the free list. */
8773 #ifdef ENABLE_GC_CHECKING
8774 /* Poison the data, to indicate the data is garbage. */
8777 #endif
8778 /* Let valgrind know the object is free. */
8781 /* Let valgrind know the next portion of the object is available,
8782 but uninitialized. */
8784 }
8786 /* Bring an object that underwent at least one lifecycle after anew
8787 and before the most recent free and poison, back to a usable
8788 state, reinitializing whatever is needed for it to be
8789 functionally equivalent to an object just allocated and returned
8790 by anew. This may poison or clear the next field, used by
8791 freelist housekeeping after poison was called. */
8795 #ifdef ENABLE_GC_CHECKING
8797 #endif
8798 /* Let valgrind know the entire object is available, but
8799 uninitialized. */
8801 }
8803 /* Reference a GTY-deletable pointer that points to the first object
8804 in the free list proper. */
8807 /* Construct a freelist object chaining objects off of HEAD. */
8810 /* Add OBJ to the free object list. The former head becomes OBJ's
8811 successor. */
8813 {
8817 }
8819 /* Take an object from the free list, if one is available, or
8820 allocate a new one. Objects taken from the free list should be
8821 regarded as filled with garbage, except for bits that are
8822 configured to be preserved across free and alloc. */
8824 {
8826 {
8831 }
8832 else
8834 }
8835 };
8837 /* Explicitly specialize the interfaces for freelist<tree_node>: we
8838 want to allocate a TREE_LIST using the usual interface, and ensure
8839 TREE_CHAIN remains functional. Alas, we have to duplicate a bit of
8840 build_tree_list logic in reinit, so this could go out of sync. */
8844 {
8846 }
8848 inline tree
8850 {
8852 }
8856 {
8862 #ifdef ENABLE_GC_CHECKING
8865 /* Poison the data, to indicate the data is garbage. */
8868 #endif
8869 /* Let valgrind know the object is free. */
8871 /* But we still want to use the TREE_CODE and TREE_CHAIN parts. */
8875 #ifdef ENABLE_GC_CHECKING
8877 /* Keep TREE_CHAIN functional. */
8879 #else
8881 #endif
8882 }
8886 {
8889 #ifdef ENABLE_GC_CHECKING
8893 #endif
8895 /* Let valgrind know the entire object is available, but
8896 uninitialized. */
8899 #ifdef ENABLE_GC_CHECKING
8901 #else
8903 #endif
8904 }
8906 /* Point to the first object in the TREE_LIST freelist. */
8908 /* Return the/an actual TREE_LIST freelist. */
8911 {
8913 }
8915 /* Point to the first object in the tinst_level freelist. */
8917 /* Return the/an actual tinst_level freelist. */
8920 {
8922 }
8924 /* Point to the first object in the pending_template freelist. */
8926 /* Return the/an actual pending_template freelist. */
8929 {
8931 }
8933 /* Build the TREE_LIST object out of a split list, store it
8934 permanently, and return it. */
8935 tree
8937 {
8946 }
8950 /* Increment OBJ's refcount unless it is already infinite. */
8953 {
8957 }
8959 /* Release storage for OBJ and node, if it's a TREE_LIST. */
8960 void
8962 {
8966 }
8968 /* Decrement OBJ's refcount if not infinite. If it reaches zero, release
8969 OBJ's DECL and OBJ, and start over with the tinst_level object that
8970 used to be referenced by OBJ's NEXT. */
8971 static void
8973 {
8977 {
8981 }
8982 }
8984 /* Modify PTR so that it points to OBJ, adjusting the refcounts of OBJ
8985 and of the former PTR. Omitting the second argument is equivalent
8986 to passing (T*)NULL; this is allowed because passing the
8987 zero-valued integral constant NULL confuses type deduction and/or
8988 overload resolution. */
8990 static void
8992 {
8996 }
8998 static void
9000 {
9010 /* We are called both from instantiate_decl, where we've already had a
9011 tinst_level pushed, and instantiate_template, where we haven't.
9012 Compensate. */
9014 level = !current_tinst_level
9026 else
9035 }
9038 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
9039 ARGLIST. Valid choices for FNS are given in the cp-tree.def
9040 documentation for TEMPLATE_ID_EXPR. */
9042 tree
9044 {
9045 tree type;
9053 {
9056 }
9059 {
9061 unknown_type_node,
9063 arglist);
9065 }
9072 }
9074 /* Within the scope of a template class S<T>, the name S gets bound
9075 (in build_self_reference) to a TYPE_DECL for the class, not a
9076 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
9077 or one of its enclosing classes, and that type is a template,
9078 return the associated TEMPLATE_DECL. Otherwise, the original
9079 DECL is returned.
9081 Also handle the case when DECL is a TREE_LIST of ambiguous
9082 injected-class-names from different bases. */
9084 tree
9086 {
9090 /* DR 176: A lookup that finds an injected-class-name (10.2
9091 [class.member.lookup]) can result in an ambiguity in certain cases
9092 (for example, if it is found in more than one base class). If all of
9093 the injected-class-names that are found refer to specializations of
9094 the same class template, and if the name is followed by a
9095 template-argument-list, the reference refers to the class template
9096 itself and not a specialization thereof, and is not ambiguous. */
9098 {
9101 {
9107 }
9110 else
9112 }
9118 }
9120 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
9121 parameters, find the desired type.
9123 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
9125 IN_DECL, if non-NULL, is the template declaration we are trying to
9126 instantiate.
9128 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
9129 the class we are looking up.
9131 Issue error and warning messages under control of COMPLAIN.
9133 If the template class is really a local class in a template
9134 function, then the FUNCTION_CONTEXT is the function in which it is
9135 being instantiated.
9137 ??? Note that this function is currently called *twice* for each
9138 template-id: the first time from the parser, while creating the
9139 incomplete type (finish_template_type), and the second type during the
9140 real instantiation (instantiate_template_class). This is surely something
9141 that we want to avoid. It also causes some problems with argument
9142 coercion (see convert_nontype_argument for more information on this). */
9144 static tree
9147 {
9149 tree t;
9152 spec_entry elt;
9153 hashval_t hash;
9156 {
9160 else
9161 {
9168 }
9171 }
9173 {
9176 /* If we are declaring a constructor, say A<T>::A<T>, we will get
9177 an implicit typename for the second A. Deal with it. */
9182 {
9185 }
9186 }
9189 {
9192 }
9194 {
9198 }
9200 {
9203 }
9205 /* Issue an error message if we didn't find a template. */
9207 {
9211 }
9214 /* Make sure it's a user visible template, if it was named by
9215 the user. */
9218 {
9220 {
9224 }
9226 }
9230 /* An alias that just changes the name of a template is equivalent to the
9231 other template, so if any of the arguments are pack expansions, strip
9232 the alias to avoid problems with a pack expansion passed to a non-pack
9233 alias template parameter (DR 1430). */
9238 {
9239 tree parm;
9248 }
9249 else
9250 {
9252 tree gen_tmpl;
9253 tree type_decl;
9261 /* An error occurred while building the template TEMPL, and a
9262 diagnostic has most certainly been emitted for that
9263 already. Let's propagate that error. */
9272 {
9273 /* We've been given an incomplete set of template arguments.
9274 For example, given:
9276 template <class T> struct S1 {
9277 template <class U> struct S2 {};
9278 template <class U> struct S2<U*> {};
9279 };
9281 we will be called with an ARGLIST of `U*', but the
9282 TEMPLATE will be `template <class T> template
9283 <class U> struct S1<T>::S2'. We must fill in the missing
9284 arguments. */
9288 }
9290 /* Now we should have enough arguments. */
9293 /* From here on, we're only interested in the most general
9294 template. */
9296 /* Calculate the BOUND_ARGS. These will be the args that are
9297 actually tsubst'd into the definition to create the
9298 instantiation. */
9300 complain,
9305 /* We were unable to bind the arguments. */
9308 /* In the scope of a template class, explicit references to the
9309 template class refer to the type of the template, not any
9310 instantiation of it. For example, in:
9312 template <class T> class C { void f(C<T>); }
9314 the `C<T>' is just the same as `C'. Outside of the
9315 class, however, such a reference is an instantiation. */
9319 {
9324 }
9326 /* If we already have this specialization, return it. */
9336 /* If the the template's constraints are not satisfied,
9337 then we cannot form a valid type.
9339 Note that the check is deferred until after the hash
9340 lookup. This prevents redundant checks on previously
9341 instantiated specializations. */
9343 {
9345 {
9348 }
9350 }
9354 /* If the deduced arguments are invalid, then the binding
9355 failed. */
9359 complain))
9366 {
9371 }
9381 /* Create the type. */
9383 {
9384 /* The user referred to a specialization of an alias
9385 template represented by GEN_TMPL.
9387 [temp.alias]/2 says:
9389 When a template-id refers to the specialization of an
9390 alias template, it is equivalent to the associated
9391 type obtained by substitution of its
9392 template-arguments for the template-parameters in the
9393 type-id of the alias template. */
9396 /* Note that the call above (by indirectly calling
9397 register_specialization in tsubst_decl) registers the
9398 TYPE_DECL representing the specialization of the alias
9399 template. So next time someone substitutes ARGLIST for
9400 the template parms into the alias template (GEN_TMPL),
9401 she'll get that TYPE_DECL back. */
9405 }
9407 {
9409 {
9420 }
9421 else
9422 {
9423 /* We don't want to call start_enum for this type, since
9424 the values for the enumeration constants may involve
9425 template parameters. And, no one should be interested
9426 in the enumeration constants for such a type. */
9429 }
9433 }
9435 {
9436 /* Lambda closures are regenerated in tsubst_lambda_expr, not
9437 instantiated here. */
9445 /* A local class. Make sure the decl gets registered properly. */
9452 /* This instantiation is another name for the primary
9453 template type. Set the TYPE_CANONICAL field
9454 appropriately. */
9457 /* Some of the template arguments require structural
9458 equality testing, so this template class requires
9459 structural equality testing. */
9461 }
9462 else
9465 /* If we called start_enum or pushtag above, this information
9466 will already be set up. */
9468 {
9475 }
9476 else
9480 {
9486 {
9489 }
9490 }
9494 {
9498 {
9499 tree attributes
9507 }
9508 }
9510 /* Let's consider the explicit specialization of a member
9511 of a class template specialization that is implicitly instantiated,
9512 e.g.:
9513 template<class T>
9514 struct S
9515 {
9516 template<class U> struct M {}; //#0
9517 };
9519 template<>
9520 template<>
9521 struct S<int>::M<char> //#1
9522 {
9523 int i;
9524 };
9525 [temp.expl.spec]/4 says this is valid.
9527 In this case, when we write:
9528 S<int>::M<char> m;
9530 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
9531 the one of #0.
9533 When we encounter #1, we want to store the partial instantiation
9534 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
9536 For all cases other than this "explicit specialization of member of a
9537 class template", we just want to store the most general template into
9538 the CLASSTYPE_TI_TEMPLATE of M.
9540 This case of "explicit specialization of member of a class template"
9541 only happens when:
9542 1/ the enclosing class is an instantiation of, and therefore not
9543 the same as, the context of the most general template, and
9544 2/ we aren't looking at the partial instantiation itself, i.e.
9545 the innermost arguments are not the same as the innermost parms of
9546 the most general template.
9548 So it's only when 1/ and 2/ happens that we want to use the partial
9549 instantiation of the member template in lieu of its most general
9550 template. */
9554 /* the enclosing class must be an instantiation... */
9557 {
9561 tree partial_inst_args =
9568 use_partial_inst_tmpl =
9569 /*...and we must not be looking at the partial instantiation
9570 itself. */
9572 partial_inst_args);
9573 }
9576 /* This case is easy; there are no member templates involved. */
9578 else
9579 {
9580 /* This is a full instantiation of a member template. Find
9581 the partial instantiation of which this is an instance. */
9583 /* Temporarily reduce by one the number of levels in the ARGLIST
9584 so as to avoid comparing the last set of arguments. */
9588 /* FOUND is either a proper class type, or an alias
9589 template specialization. In the later case, it's a
9590 TYPE_DECL, resulting from the substituting of arguments
9591 for parameters in the TYPE_DECL of the alias template
9592 done earlier. So be careful while getting the template
9593 of FOUND. */
9595 ? found
9599 }
9601 // Build template info for the new specialization.
9610 /* Note this use of the partial instantiation so we can check it
9611 later in maybe_process_partial_specialization. */
9618 /* Now that the type has been registered on the instantiations
9619 list, we set up the enumerators. Because the enumeration
9620 constants may involve the enumeration type itself, we make
9621 sure to register the type first, and then create the
9622 constants. That way, doing tsubst_expr for the enumeration
9623 constants won't result in recursive calls here; we'll find
9624 the instantiation and exit above. */
9628 /* If the type makes use of template parameters, the
9629 code that generates debugging information will crash. */
9632 /* Possibly limit visibility based on template args. */
9639 }
9640 }
9642 /* Wrapper for lookup_template_class_1. */
9644 tree
9647 {
9648 tree ret;
9654 }
9656 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
9658 tree
9660 {
9661 /* The type of the expression is NULL_TREE since the template-id could refer
9662 to an explicit or partial specialization. */
9665 /* Except that concepts are always bool. */
9668 }
9670 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9672 tree
9674 {
9678 /* We never want to return a VAR_DECL for a variable concept, since they
9679 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
9694 {
9696 {
9699 }
9701 }
9703 /* If a template-id refers to a specialization of a variable
9704 concept, then the expression is true if and only if the
9705 concept's constraints are satisfied by the given template
9706 arguments.
9708 NOTE: This is an extension of Concepts Lite TS that
9709 allows constraints to be used in expressions. */
9711 {
9714 }
9717 }
9719 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
9720 TARGS template args, and instantiate it if it's not dependent. */
9722 tree
9724 tsubst_flags_t complain)
9725 {
9728 {
9731 }
9734 }
9736 \f
9737 struct pair_fn_data
9738 {
9739 tree_fn_t fn;
9740 tree_fn_t any_fn;
9742 /* True when we should also visit template parameters that occur in
9743 non-deduced contexts. */
9746 };
9748 /* Called from for_each_template_parm via walk_tree. */
9750 static tree
9752 {
9759 #define WALK_SUBTREE(NODE) \
9760 do \
9761 { \
9762 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
9763 pfd->include_nondeduced_p, \
9764 pfd->any_fn); \
9765 if (result) goto out; \
9766 } \
9767 while (0)
9777 {
9781 /* Fall through. */
9787 else
9797 /* Since we're not going to walk subtrees, we have to do this
9798 explicitly here. */
9800 /* Fall through. */
9803 /* Check the return type. */
9806 /* Check the parameter types. Since default arguments are not
9807 instantiated until they are needed, the TYPE_ARG_TYPES may
9808 contain expressions that involve template parameters. But,
9809 no-one should be looking at them yet. And, once they're
9810 instantiated, they don't contain template parameters, so
9811 there's no point in looking at them then, either. */
9812 {
9813 tree parm;
9818 /* Since we've already handled the TYPE_ARG_TYPES, we don't
9819 want walk_tree walking into them itself. */
9821 }
9824 {
9828 }
9845 /* Fall through. */
9857 /* Record template parameters such as `T' inside `TT<T>'. */
9859 /* Fall through. */
9871 /* A template template parameter is encountered. */
9875 /* Already substituted template template parameter */
9880 /* A template-id in a TYPENAME_TYPE might be a deduced context after
9881 partial instantiation. */
9893 /* If there's no type, then this thing must be some expression
9894 involving template parameters. */
9916 }
9918 #undef WALK_SUBTREE
9920 /* We didn't find any template parameters we liked. */
9921 out:
9923 }
9925 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9926 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9927 call FN with the parameter and the DATA.
9928 If FN returns nonzero, the iteration is terminated, and
9929 for_each_template_parm returns 1. Otherwise, the iteration
9930 continues. If FN never returns a nonzero value, the value
9931 returned by for_each_template_parm is 0. If FN is NULL, it is
9932 considered to be the function which always returns 1.
9934 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9935 parameters that occur in non-deduced contexts. When false, only
9936 visits those template parameters that can be deduced. */
9938 static tree
9942 tree_fn_t any_fn)
9943 {
9945 tree result;
9947 /* Set up. */
9953 /* Walk the tree. (Conceptually, we would like to walk without
9954 duplicates, but for_each_template_parm_r recursively calls
9955 for_each_template_parm, so we would need to reorganize a fair
9956 bit to use walk_tree_without_duplicates, so we keep our own
9957 visited list.) */
9960 else
9963 for_each_template_parm_r,
9967 /* Clean up. */
9969 {
9972 }
9975 }
9977 /* Returns true if T depends on any template parameter. */
9979 int
9981 {
10011 else
10012 {
10015 }
10020 }
10022 /* Returns true iff current_function_decl is an incompletely instantiated
10023 template. Useful instead of processing_template_decl because the latter
10024 is set to 0 during instantiate_non_dependent_expr. */
10026 bool
10028 {
10037 }
10039 /* Returns true if T depends on any template parameter with level LEVEL. */
10041 bool
10043 {
10046 }
10048 /* Returns true if the signature of DECL depends on any template parameter from
10049 its enclosing class. */
10051 bool
10053 {
10063 template_parm_outer_level,
10073 }
10075 /* Returns TRUE iff INST is an instantiation we don't need to do in an
10076 ill-formed translation unit, i.e. a variable or function that isn't
10077 usable in a constant expression. */
10081 {
10086 }
10088 /* Returns TRUE iff we should refuse to instantiate DECL because it's
10089 neglectable and instantiated from within an erroneous instantiation. */
10091 static bool
10093 {
10104 }
10112 /* We're starting to instantiate D; record the template instantiation context
10113 at LOC for diagnostics and to restore it later. */
10115 static bool
10117 {
10121 {
10122 /* Tell error.c not to try to instantiate any templates. */
10125 "template instantiation depth exceeds maximum of %d"
10127 max_tinst_depth);
10129 }
10131 /* If the current instantiation caused problems, don't let it instantiate
10132 anything else. Do allow deduction substitution and decls usable in
10133 constant expressions. */
10137 /* When not -quiet, dump template instantiations other than functions, since
10138 announce_function will take care of those. */
10159 }
10161 /* We're starting substitution of TMPL<ARGS>; record the template
10162 substitution context for diagnostics and to restore it later. */
10164 static bool
10166 {
10168 }
10170 /* We're starting to instantiate D; record INPUT_LOCATION and the
10171 template instantiation context for diagnostics and to restore it
10172 later. */
10174 bool
10176 {
10178 }
10180 /* Likewise, but record LOC as the program location. */
10182 bool
10184 {
10187 }
10189 /* We're done instantiating this template; return to the instantiation
10190 context. */
10192 void
10194 {
10195 /* Restore the filename and line number stashed away when we started
10196 this instantiation. */
10200 }
10202 /* We're instantiating a deferred template; restore the template
10203 instantiation context in which the instantiation was requested, which
10204 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
10206 static tree
10208 {
10220 }
10222 /* Returns the TINST_LEVEL which gives the original instantiation
10223 context. */
10227 {
10233 }
10235 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
10236 vector of template arguments, as for tsubst.
10238 Returns an appropriate tsubst'd friend declaration. */
10240 static tree
10242 {
10243 tree new_friend;
10248 /* This was a friend declared with an explicit template
10249 argument list, e.g.:
10251 friend void f<>(T);
10253 to indicate that f was a template instantiation, not a new
10254 function declaration. Now, we have to figure out what
10255 instantiation of what template. */
10256 {
10258 tree new_args;
10259 tree tmpl;
10262 /* Friend functions are looked up in the containing namespace scope.
10263 We must enter that scope, to avoid finding member functions of the
10264 current class with same name. */
10279 tsk_none);
10281 }
10285 /* The NEW_FRIEND will look like an instantiation, to the
10286 compiler, but is not an instantiation from the point of view of
10287 the language. For example, we might have had:
10289 template <class T> struct S {
10290 template <class U> friend void f(T, U);
10291 };
10293 Then, in S<int>, template <class U> void f(int, U) is not an
10294 instantiation of anything. */
10300 {
10304 }
10306 /* The mangled name for the NEW_FRIEND is incorrect. The function
10307 is not a template instantiation and should not be mangled like
10308 one. Therefore, we forget the mangling here; we'll recompute it
10309 later if we need it. */
10311 {
10314 }
10317 {
10318 tree old_decl;
10319 tree new_friend_template_info;
10320 tree new_friend_result_template_info;
10321 tree ns;
10324 /* We must save some information from NEW_FRIEND before calling
10325 duplicate decls since that function will free NEW_FRIEND if
10326 possible. */
10328 new_friend_is_defn =
10333 {
10334 /* This declaration is a `primary' template. */
10337 new_friend_result_template_info
10339 }
10340 else
10343 /* Inside pushdecl_namespace_level, we will push into the
10344 current namespace. However, the friend function should go
10345 into the namespace of the template. */
10355 {
10356 /* This new friend declaration matched an existing
10357 declaration. For example, given:
10359 template <class T> void f(T);
10360 template <class U> class C {
10361 template <class T> friend void f(T) {}
10362 };
10364 the friend declaration actually provides the definition
10365 of `f', once C has been instantiated for some type. So,
10366 old_decl will be the out-of-class template declaration,
10367 while new_friend is the in-class definition.
10369 But, if `f' was called before this point, the
10370 instantiation of `f' will have DECL_TI_ARGS corresponding
10371 to `T' but not to `U', references to which might appear
10372 in the definition of `f'. Previously, the most general
10373 template for an instantiation of `f' was the out-of-class
10374 version; now it is the in-class version. Therefore, we
10375 run through all specialization of `f', adding to their
10376 DECL_TI_ARGS appropriately. In particular, they need a
10377 new set of outer arguments, corresponding to the
10378 arguments for this class instantiation.
10380 The same situation can arise with something like this:
10382 friend void f(int);
10383 template <class T> class C {
10384 friend void f(T) {}
10385 };
10387 when `C<int>' is instantiated. Now, `f(int)' is defined
10388 in the class. */
10391 /* On the other hand, if the in-class declaration does
10392 *not* provide a definition, then we don't want to alter
10393 existing definitions. We can just leave everything
10394 alone. */
10395 ;
10396 else
10397 {
10401 /* Overwrite whatever template info was there before, if
10402 any, with the new template information pertaining to
10403 the declaration. */
10407 {
10408 /* We should have called reregister_specialization in
10409 duplicate_decls. */
10414 /* Instantiate it if the global has already been used. */
10418 }
10419 else
10420 {
10421 tree t;
10423 /* Indicate that the old function template is a partial
10424 instantiation. */
10432 /* Reassign any specializations already in the hash table
10433 to the new more general template, and add the
10434 additional template args. */
10438 {
10440 spec_entry elt;
10452 register_specialization
10455 }
10457 }
10458 }
10460 /* The information from NEW_FRIEND has been merged into OLD_DECL
10461 by duplicate_decls. */
10463 }
10464 }
10465 else
10466 {
10470 /* In the code
10471 template <class T> class C {
10472 template <class U> friend void C1<U>::f (); // case 1
10473 friend void C2<T>::f (); // case 2
10474 };
10475 we only need to make sure CONTEXT is a complete type for
10476 case 2. To distinguish between the two cases, we note that
10477 CONTEXT of case 1 remains dependent type after tsubst while
10478 this isn't true for case 2. */
10488 {
10490 /* do_friend adds the TEMPLATE_DECL for any member friend
10491 template even if it isn't a member template, i.e.
10492 template <class T> friend A<T>::f();
10493 Look through it in that case. */
10497 /* Check to see that the declaration is really present, and,
10498 possibly obtain an improved declaration. */
10503 }
10504 }
10507 }
10509 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
10510 template arguments, as for tsubst.
10512 Returns an appropriate tsubst'd friend type or error_mark_node on
10513 failure. */
10515 static tree
10517 {
10518 tree tmpl;
10521 {
10524 }
10529 else
10537 {
10538 /* The friend template has already been declared. Just
10539 check to see that the declarations match, and install any new
10540 default parameters. We must tsubst the default parameters,
10541 of course. We only need the innermost template parameters
10542 because that is all that redeclare_class_template will look
10543 at. */
10546 {
10554 }
10555 }
10556 else
10557 {
10558 /* The friend template has not already been declared. In this
10559 case, the instantiation of the template class will cause the
10560 injection of this template into the namespace scope. */
10564 {
10565 /* The new TMPL is not an instantiation of anything, so we
10566 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
10567 for the new type because that is supposed to be the
10568 corresponding template decl, i.e., TMPL. */
10575 /* It is hidden. */
10580 /* Inject this template into the enclosing namspace scope. */
10582 }
10583 }
10587 else
10591 }
10593 /* Returns zero if TYPE cannot be completed later due to circularity.
10594 Otherwise returns one. */
10596 static int
10598 {
10608 else
10610 }
10615 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
10616 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
10618 static tree
10621 {
10630 {
10637 clauses
10641 else
10643 }
10644 /* If the first attribute argument is an identifier, don't
10645 pass it through tsubst. Attributes like mode, format,
10646 cleanup and several target specific attributes expect it
10647 unmodified. */
10649 {
10650 tree chain
10655 }
10657 {
10658 /* An attribute pack expansion. */
10667 {
10671 }
10673 }
10674 else
10681 }
10683 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
10684 unchanged or a new TREE_LIST chain. */
10686 static tree
10689 {
10694 {
10698 }
10702 {
10705 {
10708 {
10714 }
10715 }
10717 }
10720 }
10722 /* Apply any attributes which had to be deferred until instantiation
10723 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
10724 ARGS, COMPLAIN, IN_DECL are as tsubst. */
10726 static void
10729 {
10731 tree t;
10738 {
10742 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
10743 to our attributes parameter. */
10745 }
10746 else
10747 {
10749 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
10750 lookup_template_class_1, and should be preserved. */
10754 }
10758 {
10762 }
10766 {
10771 {
10774 {
10780 }
10781 else
10783 }
10786 }
10787 }
10789 /* Perform (or defer) access check for typedefs that were referenced
10790 from within the template TMPL code.
10791 This is a subroutine of instantiate_decl and instantiate_class_template.
10792 TMPL is the template to consider and TARGS is the list of arguments of
10793 that template. */
10795 static void
10797 {
10798 location_t saved_location;
10809 {
10821 /* Make access check error messages point to the location
10822 of the use of the typedef. */
10826 tf_warning_or_error);
10827 }
10829 }
10831 static tree
10833 {
10835 tree typedecl;
10836 tree pbinfo;
10837 tree base_list;
10839 tree fn_context;
10848 /* Figure out which template is being instantiated. */
10852 /* Mark the type as in the process of being defined. */
10855 /* Determine what specialization of the original template to
10856 instantiate. */
10861 {
10862 /* This TYPE is actually an instantiation of a partial
10863 specialization. We replace the innermost set of ARGS with
10864 the arguments appropriate for substitution. For example,
10865 given:
10867 template <class T> struct S {};
10868 template <class T> struct S<T*> {};
10870 and supposing that we are instantiating S<int*>, ARGS will
10871 presently be {int*} -- but we need {int}. */
10874 }
10875 else
10876 {
10879 }
10881 /* If the template we're instantiating is incomplete, then clearly
10882 there's nothing we can do. */
10884 {
10885 /* We can try again later. */
10888 }
10890 /* If we've recursively instantiated too many templates, stop. */
10894 /* We may be in the middle of deferred access check. Disable
10895 it now. */
10902 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10907 else
10908 {
10911 }
10912 /* Use #pragma pack from the template context. */
10918 /* Set the input location to the most specialized template definition.
10919 This is needed if tsubsting causes an error. */
10931 {
10934 /* Adjust visibility for template arguments. */
10936 }
10942 /* We should never instantiate a nested class before its enclosing
10943 class; we need to look up the nested class by name before we can
10944 instantiate it, and that lookup should instantiate the enclosing
10945 class. */
10951 {
10952 tree pbase_binfo;
10953 tree pushed_scope;
10956 /* We must enter the scope containing the type, as that is where
10957 the accessibility of types named in dependent bases are
10958 looked up from. */
10961 /* Substitute into each of the bases to determine the actual
10962 basetypes. */
10964 {
10965 tree base;
10971 {
10972 expanded_bases =
10979 }
10982 {
10984 /* Extract the already-expanded base class. */
10986 else
10987 /* Substitute to figure out the base class. */
10989 NULL_TREE);
10997 }
10998 }
11000 /* The list is now in reverse order; correct that. */
11005 }
11006 /* Now call xref_basetypes to set up all the base-class
11007 information. */
11015 /* Now that our base classes are set up, enter the scope of the
11016 class, so that name lookups into base classes, etc. will work
11017 correctly. This is precisely analogous to what we do in
11018 begin_class_definition when defining an ordinary non-template
11019 class, except we also need to push the enclosing classes. */
11022 /* Now members are processed in the order of declaration. */
11025 {
11029 {
11031 {
11033 /* A closure type for a lambda in an NSDMI or default argument.
11034 Ignore it; it will be regenerated when needed. */
11037 /* Build new CLASSTYPE_NESTED_UTDS. */
11039 tree newtag;
11045 /* If the member is a class template, then -- even after
11046 substitution -- there may be dependent types in the
11047 template argument list for the class. We increment
11048 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
11049 that function will assume that no types are dependent
11050 when outside of a template. */
11060 {
11064 /* Unfortunately, lookup_template_class sets
11065 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
11066 instantiation (i.e., for the type of a member
11067 template class nested within a template class.)
11068 This behavior is required for
11069 maybe_process_partial_specialization to work
11070 correctly, but is not accurate in this case;
11071 the TAG is not an instantiation of anything.
11072 (The corresponding TEMPLATE_DECL is an
11073 instantiation, but the TYPE is not.) */
11076 /* Now, we call pushtag to put this NEWTAG into the scope of
11077 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
11078 pushtag calling push_template_decl. We don't have to do
11079 this for enums because it will already have been done in
11080 tsubst_enum. */
11084 }
11085 }
11087 {
11088 tree r;
11097 /* Instantiate members marked with attribute used. */
11103 }
11106 /* A closure type for a lambda in an NSDMI or default argument.
11108 else
11109 {
11110 /* Build new TYPE_FIELDS. */
11112 {
11113 tree condition;
11116 condition =
11126 }
11128 {
11129 tree r;
11133 /* The file and line for this declaration, to
11134 assist in error message reporting. Since we
11135 called push_tinst_level above, we don't need to
11136 restore these. */
11146 {
11147 /* A capture pack became multiple fields. */
11150 }
11153 {
11157 {
11158 /* In [temp.inst]:
11160 [t]he initialization (and any associated
11161 side-effects) of a static data member does
11162 not occur unless the static data member is
11163 itself used in a way that requires the
11164 definition of the static data member to
11165 exist.
11167 Therefore, we do not substitute into the
11168 initialized for the static data member here. */
11169 finish_static_data_member_decl
11175 /* Instantiate members marked with attribute used. */
11178 }
11180 {
11181 /* Determine whether R has a valid type and can be
11182 completed later. If R is invalid, then its type
11183 is replaced by error_mark_node. */
11189 {
11190 /* If R's type couldn't be completed and
11191 it isn't a flexible array member (whose
11192 type is incomplete by definition) give
11193 an error. */
11196 }
11201 {
11204 }
11205 }
11207 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
11208 such a thing will already have been added to the field
11209 list by tsubst_enum in finish_member_declaration in the
11210 CLASSTYPE_NESTED_UTDS case above. */
11214 {
11217 }
11218 }
11219 }
11220 }
11221 }
11222 else
11223 {
11226 {
11227 /* Build new CLASSTYPE_FRIEND_CLASSES. */
11233 {
11234 /* template <class T> friend class C; */
11237 }
11239 {
11240 /* template <class T> friend class C::D; */
11246 }
11249 {
11250 /* This could be either
11252 friend class T::C;
11254 when dependent_type_p is false or
11256 template <class U> friend class T::C;
11258 otherwise. */
11259 /* Bump processing_template_decl in case this is something like
11260 template <class T> friend struct A<T>::B. */
11267 }
11271 {
11272 /* friend class C;
11274 where C hasn't been declared yet. Let's lookup name
11275 from namespace scope directly, bypassing any name that
11276 come from dependent base class. */
11279 /* The call to xref_tag_from_type does injection for friend
11280 classes. */
11282 friend_type =
11286 }
11288 /* friend class C<T>; */
11291 /* Otherwise it's
11293 friend class C;
11295 where C is already declared or
11297 friend class C<int>;
11299 We don't have to do anything in these cases. */
11302 /* Trick make_friend_class into realizing that the friend
11303 we're adding is a template, not an ordinary class. It's
11304 important that we use make_friend_class since it will
11305 perform some error-checking and output cross-reference
11306 information. */
11314 }
11315 else
11316 {
11317 /* Build new DECL_FRIENDLIST. */
11318 tree r;
11320 /* The file and line for this declaration, to
11321 assist in error message reporting. Since we
11322 called push_tinst_level above, we don't need to
11323 restore these. */
11327 {
11330 }
11335 {
11338 }
11339 }
11340 }
11341 }
11344 {
11345 /* Restore these before substituting into the lambda capture
11346 initializers. */
11349 }
11351 /* Set the file and line number information to whatever is given for
11352 the class itself. This puts error messages involving generated
11353 implicit functions at a predictable point, and the same point
11354 that would be used for non-template classes. */
11361 /* We don't instantiate default arguments for member functions. 14.7.1:
11363 The implicit instantiation of a class template specialization causes
11364 the implicit instantiation of the declarations, but not of the
11365 definitions or default arguments, of the class member functions,
11366 member classes, static data members and member templates.... */
11368 /* Some typedefs referenced from within the template code need to be access
11369 checked at template instantiation time, i.e now. These types were
11370 added to the template at parsing time. Let's get those and perform
11371 the access checks then. */
11381 /* The vtable for a template class can be emitted in any translation
11382 unit in which the class is instantiated. When there is no key
11383 method, however, finish_struct_1 will already have added TYPE to
11384 the keyed_classes. */
11389 }
11391 /* Wrapper for instantiate_class_template_1. */
11393 tree
11395 {
11396 tree ret;
11401 }
11403 static tree
11405 {
11406 tree r;
11412 else
11413 {
11420 }
11422 }
11424 /* Given a function parameter pack TMPL_PARM and some function parameters
11425 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
11426 and set *SPEC_P to point at the next point in the list. */
11428 tree
11430 {
11431 /* Collect all of the extra "packed" parameters into an
11432 argument pack. */
11433 tree parmvec;
11443 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
11447 {
11452 }
11454 /* Build the argument packs. */
11459 }
11461 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
11462 NONTYPE_ARGUMENT_PACK. */
11464 static tree
11466 {
11468 }
11470 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
11471 pack expansion with no extra args, 2 if it has extra args, or 0
11472 if it is not a pack expansion. */
11474 static int
11476 {
11482 /* A decl pack is itself an expansion. */
11489 }
11492 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
11494 static tree
11496 {
11503 }
11505 /* This is a subroutine of tsubst_pack_expansion.
11507 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
11508 mechanism to store the (non complete list of) arguments of the
11509 substitution and return a non substituted pack expansion, in order
11510 to wait for when we have enough arguments to really perform the
11511 substitution. */
11513 static bool
11517 {
11518 /* If one pack has an expansion and another pack has a normal
11519 argument or if one pack has an empty argument and an another
11520 one hasn't then tsubst_pack_expansion cannot perform the
11521 substitution and need to fall back on the
11522 PACK_EXPANSION_EXTRA mechanism. */
11530 {
11533 parm_pack;
11535 {
11540 /* We can't substitute a pack expansion with extra args into
11541 our pattern. */
11545 else
11547 }
11551 }
11553 }
11555 /* [temp.variadic]/6 says that:
11557 The instantiation of a pack expansion [...]
11558 produces a list E1,E2, ..., En, where N is the number of elements
11559 in the pack expansion parameters.
11561 This subroutine of tsubst_pack_expansion produces one of these Ei.
11563 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
11564 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
11565 PATTERN, and each TREE_VALUE is its corresponding argument pack.
11566 INDEX is the index 'i' of the element Ei to produce. ARGS,
11567 COMPLAIN, and IN_DECL are the same parameters as for the
11568 tsubst_pack_expansion function.
11570 The function returns the resulting Ei upon successful completion,
11571 or error_mark_node.
11573 Note that this function possibly modifies the ARGS parameter, so
11574 it's the responsibility of the caller to restore it. */
11576 static tree
11578 tree parm_packs,
11580 tree args /* This parm gets
11582 tsubst_flags_t complain,
11583 tree in_decl)
11584 {
11585 tree t;
11588 /* For each parameter pack, change the substitution of the parameter
11589 pack to the ith argument in its argument pack, then expand the
11590 pattern. */
11592 {
11597 ith_elem_is_expansion |=
11600 /* Select the Ith argument from the pack. */
11604 {
11606 {
11611 }
11612 else
11614 }
11615 else
11616 {
11621 {
11623 /* Update the corresponding argument. */
11625 }
11626 else
11627 /* Re-use the ARGUMENT_PACK_SELECT. */
11629 }
11631 }
11633 /* Substitute into the PATTERN with the (possibly altered)
11634 arguments. */
11636 /* Expanding a fixed parameter pack from
11637 coerce_template_parameter_pack. */
11642 {
11645 else
11648 }
11652 else
11655 /* If the Ith argument pack element is a pack expansion, then
11656 the Ith element resulting from the substituting is going to
11657 be a pack expansion as well. */
11662 }
11664 /* When the unexpanded parameter pack in a fold expression expands to an empty
11665 sequence, the value of the expression is as follows; the program is
11666 ill-formed if the operator is not listed in this table.
11668 && true
11669 || false
11670 , void() */
11672 tree
11674 {
11678 {
11687 }
11693 }
11695 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11696 form an expression that combines the two terms using the
11697 operator of T. */
11699 static tree
11701 {
11705 // Handle compound assignment operators.
11710 {
11720 complain);
11721 }
11722 }
11724 /* Substitute ARGS into the pack of a fold expression T. */
11728 {
11730 }
11732 /* Substitute ARGS into the pack of a fold expression T. */
11736 {
11738 }
11740 /* Expand a PACK of arguments into a grouped as left fold.
11741 Given a pack containing elements A0, A1, ..., An and an
11742 operator @, this builds the expression:
11744 ((A0 @ A1) @ A2) ... @ An
11746 Note that PACK must not be empty.
11748 The operator is defined by the original fold expression T. */
11750 static tree
11752 {
11755 {
11758 }
11760 }
11762 /* Substitute into a unary left fold expression. */
11764 static tree
11766 tree in_decl)
11767 {
11772 {
11776 }
11779 else
11781 }
11783 /* Substitute into a binary left fold expression.
11785 Do ths by building a single (non-empty) vector of argumnts and
11786 building the expression from those elements. */
11788 static tree
11790 tree in_decl)
11791 {
11800 {
11805 }
11813 }
11815 /* Expand a PACK of arguments into a grouped as right fold.
11816 Given a pack containing elementns A0, A1, ..., and an
11817 operator @, this builds the expression:
11819 A0@ ... (An-2 @ (An-1 @ An))
11821 Note that PACK must not be empty.
11823 The operator is defined by the original fold expression T. */
11825 tree
11827 {
11828 // Build the expression.
11832 {
11835 }
11837 }
11839 /* Substitute into a unary right fold expression. */
11841 static tree
11843 tree in_decl)
11844 {
11849 {
11853 }
11856 else
11858 }
11860 /* Substitute into a binary right fold expression.
11862 Do ths by building a single (non-empty) vector of arguments and
11863 building the expression from those elements. */
11865 static tree
11867 tree in_decl)
11868 {
11877 {
11882 }
11891 }
11893 /* Walk through the pattern of a pack expansion, adding everything in
11894 local_specializations to a list. */
11896 struct el_data
11897 {
11899 tree extra;
11900 tsubst_flags_t complain;
11904 };
11905 static tree
11907 {
11913 /* Remember local typedefs (85214). */
11919 {
11921 /* Don't mess with variables declared within the pattern. */
11924 {
11925 /* Maybe pull out the PARM_DECL for a partial instantiation. */
11928 {
11934 }
11936 {
11937 /* Handle lambda capture here, since we aren't doing any
11938 substitution now, and so tsubst_copy won't call
11939 process_outer_var_ref. */
11943 {
11949 {
11950 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
11951 proxies. */
11953 {
11958 }
11960 }
11961 }
11962 }
11963 }
11967 }
11969 }
11970 static tree
11972 {
11976 }
11978 /* Extract any uses of local_specializations from PATTERN and add them to ARGS
11979 for use in PACK_EXPANSION_EXTRA_ARGS. */
11981 tree
11983 {
11989 }
11991 /* Apply any local specializations from PACK_EXPANSION_EXTRA_ARGS and add the
11992 normal template args to ARGS. */
11994 tree
11996 {
11998 {
12000 {
12001 /* The partial instantiation involved local declarations collected in
12002 extract_local_specs; map from the general template to our local
12003 context. */
12009 /* else inst is already a full instantiation of the pack. */
12011 }
12014 }
12016 }
12018 /* Substitute ARGS into T, which is an pack expansion
12019 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
12020 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
12021 (if only a partial substitution could be performed) or
12022 ERROR_MARK_NODE if there was an error. */
12023 tree
12025 tree in_decl)
12026 {
12027 tree pattern;
12032 tree result;
12040 /* Add in any args remembered from an earlier partial instantiation. */
12045 /* Determine the argument packs that will instantiate the parameter
12046 packs used in the expansion expression. While we're at it,
12047 compute the number of arguments to be expanded and make sure it
12048 is consistent. */
12051 {
12058 {
12064 complain);
12065 else
12069 }
12071 {
12072 /* ??? Support use in other patterns. */
12076 }
12078 {
12079 /* We know we have correct local_specializations if this
12080 expansion is at function scope, or if we're dealing with a
12081 local parameter in a requires expression; for the latter,
12082 tsubst_requires_expr set it up appropriately. */
12085 else
12086 /* We can't rely on local_specializations for a parameter
12087 name used later in a function declaration (such as in a
12088 late-specified return type). Even if it exists, it might
12089 have the wrong value for a recursive call. */
12093 {
12094 /* This parameter pack was used in an unevaluated context. Just
12095 make a dummy decl, since it's only used for its type. */
12100 /* Partial instantiation of the parm_pack, we can't build
12101 up an argument pack yet. */
12103 else
12105 }
12107 /* This argument pack isn't fully instantiated yet. We set this
12108 flag rather than clear arg_pack because we do want to do the
12109 optimization below, and we don't want to substitute directly
12110 into the pattern (as that would expose a NONTYPE_ARGUMENT_PACK
12111 where it isn't expected). */
12113 }
12115 {
12119 }
12120 else
12121 {
12127 }
12134 /* This can only happen if we forget to expand an argument
12135 pack somewhere else. Just return an error, silently. */
12136 {
12140 }
12143 {
12147 /* Don't bother trying to do a partial substitution with
12148 incomplete packs; we'll try again after deduction. */
12156 {
12161 pattern);
12162 else
12164 pattern);
12166 }
12168 /* Keep track of the parameter packs and their corresponding
12169 argument packs. */
12172 }
12173 else
12174 {
12175 /* We can't substitute for this parameter pack. We use a flag as
12176 well as the missing_level counter because function parameter
12177 packs don't have a level. */
12180 }
12181 }
12183 /* If the expansion is just T..., return the matching argument pack, unless
12184 we need to call convert_from_reference on all the elements. This is an
12185 important optimization; see c++/68422. */
12188 {
12191 /* If the argument pack is a single pack expansion, pull it out. */
12196 /* Types need no adjustment, nor does sizeof..., and if we still have
12197 some pack expansion args we won't do anything yet. */
12202 /* Also optimize expression pack expansions if we can tell that the
12203 elements won't have reference type. */
12209 /* Otherwise use the normal path so we get convert_from_reference. */
12210 }
12212 /* We cannot expand this expansion expression, because we don't have
12213 all of the argument packs we need. */
12215 {
12216 /* We got some full packs, but we can't substitute them in until we
12217 have values for all the packs. So remember these until then. */
12223 }
12225 {
12226 /* There were no real arguments, we're just replacing a parameter
12227 pack with another version of itself. Substitute into the
12228 pattern and return a PACK_EXPANSION_*. The caller will need to
12229 deal with that. */
12233 else
12237 }
12242 {
12243 /* We're in a late-specified return type, so create our own local
12244 specializations map; the current map is either NULL or (in the
12245 case of recursive unification) might have bindings that we don't
12246 want to use or alter. */
12249 }
12251 /* For each argument in each argument pack, substitute into the
12252 pattern. */
12256 {
12258 i,
12260 in_decl);
12263 {
12266 }
12267 }
12269 /* Update ARGS to restore the substitution from parameter packs to
12270 their argument packs. */
12272 {
12279 else
12280 {
12288 /* Update the corresponding argument. */
12292 else
12294 }
12295 }
12298 {
12301 }
12303 /* If the dependent pack arguments were such that we end up with only a
12304 single pack expansion again, there's no need to keep it in a TREE_VEC. */
12310 }
12312 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
12313 TMPL. We do this using DECL_PARM_INDEX, which should work even with
12314 parameter packs; all parms generated from a function parameter pack will
12315 have the same DECL_PARM_INDEX. */
12317 tree
12319 {
12321 tree patparm;
12324 {
12330 }
12331 else
12332 {
12337 }
12340 }
12342 /* Make an argument pack out of the TREE_VEC VEC. */
12344 static tree
12346 {
12347 tree pack;
12351 else
12352 {
12355 }
12358 }
12360 /* Return an exact copy of template args T that can be modified
12361 independently. */
12363 static tree
12365 {
12373 {
12378 }
12384 }
12386 /* Substitute ARGS into the vector or list of template arguments T. */
12388 static tree
12390 {
12402 {
12404 tree new_arg;
12409 {
12410 /* Substitute into an expansion expression. */
12414 /* Add to the expanded length adjustment the number of
12415 expanded arguments. We subtract one from this
12416 measurement, because the argument pack expression
12417 itself is already counted as 1 in
12418 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
12419 the argument pack is empty. */
12421 }
12423 {
12424 /* Substitute into each of the arguments. */
12433 else
12438 }
12439 else
12448 }
12453 /* Make space for the expanded arguments coming from template
12454 argument packs. */
12456 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
12457 arguments for a member template.
12458 In that case each TREE_VEC in ORIG_T represents a level of template
12459 arguments, and ORIG_T won't carry any non defaulted argument count.
12460 It will rather be the nested TREE_VECs that will carry one.
12461 In other words, ORIG_T carries a non defaulted argument count only
12462 if it doesn't contain any nested TREE_VEC. */
12464 {
12468 }
12470 {
12474 {
12477 /* Now expand the template argument pack "in place". */
12480 }
12481 else
12482 {
12484 out++;
12485 }
12486 }
12489 }
12491 /* Substitute ARGS into one level PARMS of template parameters. */
12493 static tree
12495 {
12502 {
12510 }
12513 }
12515 /* Return the result of substituting ARGS into the template parameters
12516 given by PARMS. If there are m levels of ARGS and m + n levels of
12517 PARMS, then the result will contain n levels of PARMS. For
12518 example, if PARMS is `template <class T> template <class U>
12519 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
12520 result will be `template <int*, double, class V>'. */
12522 static tree
12524 {
12528 /* When substituting into a template, we must set
12529 PROCESSING_TEMPLATE_DECL as the template parameters may be
12530 dependent if they are based on one-another, and the dependency
12531 predicates are short-circuit outside of templates. */
12538 {
12545 }
12550 }
12552 /* Return the result of substituting ARGS into one template parameter
12553 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
12554 parameter and which TREE_PURPOSE is the default argument of the
12555 template parameter. */
12557 static tree
12559 {
12580 }
12582 /* Substitute the ARGS into the indicated aggregate (or enumeration)
12583 type T. If T is not an aggregate or enumeration type, it is
12584 handled as if by tsubst. IN_DECL is as for tsubst. If
12585 ENTERING_SCOPE is nonzero, T is the context for a template which
12586 we are presently tsubst'ing. Return the substituted value. */
12588 static tree
12590 tree args,
12591 tsubst_flags_t complain,
12592 tree in_decl,
12594 {
12599 {
12604 /* Fall through. */
12608 {
12609 tree argvec;
12610 tree context;
12611 tree r;
12615 /* In "sizeof(X<I>)" we need to evaluate "I". */
12621 /* First, determine the context for the type we are looking
12622 up. */
12625 {
12628 /* If context is a nested class inside a class template,
12629 it may still need to be instantiated (c++/33959). */
12631 }
12633 /* Then, figure out what arguments are appropriate for the
12634 type we are trying to find. For example, given:
12636 template <class T> struct S;
12637 template <class T, class U> void f(T, U) { S<U> su; }
12639 and supposing that we are instantiating f<int, double>,
12640 then our ARGS will be {int, double}, but, when looking up
12641 S we only want {double}. */
12646 else
12647 {
12651 }
12657 }
12658 else
12659 /* This is not a template type, so there's nothing to do. */
12664 }
12665 }
12669 /* Substitute into the default argument ARG (a default argument for
12670 FN), which has the indicated TYPE. */
12672 tree
12674 tsubst_flags_t complain)
12675 {
12680 /* This can happen in invalid code. */
12698 /* This default argument came from a template. Instantiate the
12699 default argument here, not in tsubst. In the case of
12700 something like:
12702 template <class T>
12703 struct S {
12704 static T t();
12705 void f(T = t());
12706 };
12708 we must be careful to do name lookup in the scope of S<T>,
12709 rather than in the current class. */
12711 /* The "this" pointer is not valid in a default argument. */
12713 {
12718 }
12723 /* The default argument expression may cause implicitly defined
12724 member functions to be synthesized, which will result in garbage
12725 collection. We must treat this situation as if we were within
12726 the body of function so as to avoid collecting live data on the
12727 stack. */
12737 /* Restore the "this" pointer. */
12739 {
12742 }
12749 /* Make sure the default argument is reasonable. */
12755 {
12759 }
12762 }
12764 /* Substitute into all the default arguments for FN. */
12766 static void
12768 {
12769 tree arg;
12770 tree tmpl_args;
12774 /* If this function is not yet instantiated, we certainly don't need
12775 its default arguments. */
12778 /* Don't do this again for clones. */
12784 arg;
12790 complain);
12791 }
12793 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
12795 static tree
12797 tree lambda_fntype)
12798 {
12803 /* Nobody should be tsubst'ing into non-template functions. */
12807 {
12808 /* If T is not dependent, just return it. */
12812 /* Calculate the most general template of which R is a
12813 specialization. */
12816 /* We're substituting a lambda function under tsubst_lambda_expr but not
12817 directly from it; find the matching function we're already inside.
12818 But don't do this if T is a generic lambda with a single level of
12819 template parms, as in that case we're doing a normal instantiation. */
12825 /* Calculate the complete set of arguments used to
12826 specialize R. */
12828 (DECL_TEMPLATE_RESULT
12834 /* Check to see if we already have this specialization. */
12836 {
12840 }
12842 /* We can see more levels of arguments than parameters if
12843 there was a specialization of a member template, like
12844 this:
12846 template <class T> struct S { template <class U> void f(); }
12847 template <> template <class U> void S<int>::f(U);
12849 Here, we'll be substituting into the specialization,
12850 because that's where we can find the code we actually
12851 want to generate, but we'll have enough arguments for
12852 the most general template.
12854 We also deal with the peculiar case:
12856 template <class T> struct S {
12857 template <class U> friend void f();
12858 };
12859 template <class U> void f() {}
12860 template S<int>;
12861 template void f<double>();
12863 Here, the ARGS for the instantiation of will be {int,
12864 double}. But, we only need as many ARGS as there are
12865 levels of template parameters in CODE_PATTERN. We are
12866 careful not to get fooled into reducing the ARGS in
12867 situations like:
12869 template <class T> struct S { template <class U> void f(U); }
12870 template <class T> template <> void S<T>::f(int) {}
12872 which we can spot because the pattern will be a
12873 specialization in this case. */
12880 }
12881 else
12882 {
12883 /* This special case arises when we have something like this:
12885 template <class T> struct S {
12886 friend void f<int>(int, double);
12887 };
12889 Here, the DECL_TI_TEMPLATE for the friend declaration
12890 will be an IDENTIFIER_NODE. We are being called from
12891 tsubst_friend_function, and we want only to create a
12892 new decl (R) with appropriate types so that we can call
12893 determine_specialization. */
12896 }
12913 /* If we hit excessive deduction depth, the type is bogus even if
12914 it isn't error_mark_node, so don't build a decl. */
12918 /* We do NOT check for matching decls pushed separately at this
12919 point, as they may not represent instantiations of this
12920 template, and in any case are considered separate under the
12921 discrete model. */
12925 /* Clear out the mangled name and RTL for the instantiation. */
12928 /* Leave DECL_INITIAL set on deleted instantiations. */
12933 /* OpenMP UDRs have the only argument a reference to the declared
12934 type. We want to diagnose if the declared type is a reference,
12935 which is invalid, but as references to references are usually
12936 quietly merged, diagnose it here. */
12938 {
12939 tree argtype
12944 "reference type %qT in "
12948 argtype);
12949 }
12952 /* Type-conversion operator. Reconstruct the name, in
12953 case it's the name of one of the template's parameters. */
12963 {
12967 }
12974 /* If this is an instantiation of a function with internal
12975 linkage, we already know what object file linkage will be
12976 assigned to the instantiation. */
12985 /* We'll re-clone as appropriate in instantiate_template. */
12988 /* If we aren't complaining now, return on error before we register
12989 the specialization so that we'll complain eventually. */
12995 /* When instantiating a constrained member, substitute
12996 into the constraints to create a new constraint. */
12999 {
13002 }
13004 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
13005 this in the special friend case mentioned above where
13006 GEN_TMPL is NULL. */
13008 {
13013 tree new_r
13016 /* We instantiated this while substituting into
13017 the type earlier (template/friend54.C). */
13020 /* We're not supposed to instantiate default arguments
13021 until they are called, for a template. But, for a
13022 declaration like:
13024 template <class T> void f ()
13025 { extern void g(int i = T()); }
13027 we should do the substitution when the template is
13028 instantiated. We handle the member function case in
13029 instantiate_class_template since the default arguments
13030 might refer to other members of the class. */
13035 }
13036 else
13039 /* Copy the list of befriending classes. */
13043 {
13047 }
13050 {
13054 /* If this is an instantiation of a member template, clone it.
13055 If it isn't, that'll be handled by
13056 clone_constructors_and_destructors. */
13059 }
13070 /* Possibly limit visibility based on template args. */
13073 {
13077 }
13086 }
13088 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
13090 static tree
13092 tree lambda_fntype)
13093 {
13094 /* We can get here when processing a member function template,
13095 member class template, or template template parameter. */
13098 tree spec;
13099 tree tmpl_args;
13100 tree full_args;
13101 tree r;
13105 {
13106 /* Template template parameter is treated here. */
13110 /* If we get a real template back, return it. This can happen in
13111 the context of most_specialized_partial_spec. */
13114 else
13115 /* The new TEMPLATE_DECL was built in
13116 reduce_template_parm_level. */
13119 }
13122 {
13123 /* We might already have an instance of this template.
13124 The ARGS are for the surrounding class type, so the
13125 full args contain the tsubst'd args for the context,
13126 plus the innermost args from the template decl. */
13130 /* Because this is a template, the arguments will still be
13131 dependent, even after substitution. If
13132 PROCESSING_TEMPLATE_DECL is not set, the dependency
13133 predicates will short-circuit. */
13141 /* If this is a default template template argument,
13142 tsubst might not have changed anything. */
13150 }
13152 /* Make a new template decl. It will be similar to the
13153 original, but will record the current template arguments.
13154 We also create a new function declaration, which is just
13155 like the old one, but points to this new template, rather
13156 than the old one. */
13161 // Build new template info linking to the original template decl.
13163 {
13166 }
13167 else
13170 /* The template parameters for this new template are all the
13171 template parameters for the old template, except the
13172 outermost level of parameters. */
13175 complain);
13179 {
13180 tree new_type;
13188 /* For a partial specialization, we need to keep pointing to
13189 the primary template. */
13195 }
13196 else
13197 {
13198 tree new_decl;
13202 else
13212 {
13215 }
13216 else
13217 {
13220 }
13221 }
13231 /* Record this non-type partial instantiation. */
13237 }
13239 /* True if FN is the op() for a lambda in an uninstantiated template. */
13241 bool
13243 {
13248 }
13250 /* We're instantiating a variable from template function TCTX. Return the
13251 corresponding current enclosing scope. This gets complicated because lambda
13252 functions in templates are regenerated rather than instantiated, but generic
13253 lambda functions are subsequently instantiated. */
13255 static tree
13257 {
13266 {
13279 }
13281 }
13283 /* Substitute the ARGS into the T, which is a _DECL. Return the
13284 result of the substitution. Issue error and warning messages under
13285 control of COMPLAIN. */
13287 static tree
13289 {
13290 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
13291 location_t saved_loc;
13296 /* Set the filename and linenumber to improve error-reporting. */
13301 {
13311 {
13319 {
13320 /* If there is a local specialization that isn't a
13321 parameter pack, it means that we're doing a "simple"
13322 substitution from inside tsubst_pack_expansion. Just
13323 return the local specialization (which will be a single
13324 parm). */
13331 /* Expand the TYPE_PACK_EXPANSION that provides the types for
13332 the parameters in this function parameter pack. */
13336 {
13339 /* Zero-length parameter packs are boring. Just substitute
13340 into the chain. */
13344 }
13345 else
13346 {
13347 /* All we did was update the type. Make a note of that. */
13350 }
13351 }
13353 /* Loop through all of the parameters we'll build. When T is
13354 a function parameter pack, LEN is the number of expanded
13355 types in EXPANDED_TYPES; otherwise, LEN is 1. */
13358 {
13365 /* We're on the Ith parameter of the function parameter
13366 pack. */
13367 {
13368 /* Get the Ith type. */
13371 /* Rename the parameter to include the index. */
13374 }
13376 /* We're dealing with a normal parameter. */
13384 {
13387 else
13390 }
13400 /* Keep track of the first new parameter we
13401 generate. That's what will be returned to the
13402 caller. */
13406 /* Build a proper chain of parameters when substituting
13407 into a function parameter pack. */
13410 }
13412 /* If cp_unevaluated_operand is set, we're just looking for a
13413 single dummy parameter, so don't keep going. */
13418 /* FIRST_R contains the start of the chain we've built. */
13420 }
13424 {
13431 {
13432 /* This field is a lambda capture pack. Return a TREE_VEC of
13433 the expanded fields to instantiate_class_template_1. */
13437 {
13440 }
13441 else
13442 {
13443 /* All we did was update the type. Make a note of that. */
13446 }
13447 }
13450 {
13453 {
13457 }
13467 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
13468 number of bits. */
13474 {
13475 /* Set up DECL_TEMPLATE_INFO so that we can get at the
13476 NSDMI in perform_member_init. Still set DECL_INITIAL
13477 so that we know there is one. */
13482 }
13483 /* We don't have to set DECL_CONTEXT here; it is set by
13484 finish_member_declaration. */
13492 }
13496 }
13500 /* We reach here only for member using decls. We also need to check
13501 uses_template_parms because DECL_DEPENDENT_P is not set for a
13502 using-declaration that designates a member of the current
13503 instantiation (c++/53549). */
13506 {
13510 {
13515 {
13519 {
13522 }
13523 else
13524 {
13527 }
13529 }
13530 }
13531 else
13532 {
13538 else
13539 {
13542 }
13543 }
13544 }
13545 else
13546 {
13549 }
13554 {
13557 tree spec;
13559 tree ctx;
13568 {
13569 /* If this is the canonical decl, we don't have to
13570 mess with instantiations, and often we can't (for
13571 typename, template type parms and such). Note that
13572 TYPE_NAME is not correct for the above test if
13573 we've copied the type for a typedef. */
13579 }
13581 /* Check to see if we already have the specialization we
13582 need. */
13585 {
13586 /* T is a static data member or namespace-scope entity.
13587 We have to substitute into namespace-scope variables
13588 (not just variable templates) because of cases like:
13590 template <class T> void f() { extern T t; }
13592 where the entity referenced is not known until
13593 instantiation time. */
13597 {
13599 complain,
13601 /* If CTX is unchanged, then T is in fact the
13602 specialization we want. That situation occurs when
13603 referencing a static data member within in its own
13604 class. We can use pointer equality, rather than
13605 same_type_p, because DECL_CONTEXT is always
13606 canonical... */
13608 /* ... unless T is a member template; in which
13609 case our caller can be willing to create a
13610 specialization of that template represented
13611 by T. */
13615 }
13618 {
13623 argvec = (coerce_innermost_template_parms
13631 }
13632 }
13633 else
13634 {
13635 /* A local variable. */
13637 /* Subsequent calls to pushdecl will fill this in. */
13639 /* Unless this is a reference to a static variable from an
13640 enclosing function, in which case we need to fill it in now. */
13642 {
13646 }
13648 }
13649 /* If we already have the specialization we need, there is
13650 nothing more to do. */
13652 {
13655 }
13657 /* Create a new node for the specialization we need. */
13660 {
13663 else
13671 {
13672 /* Mask off any template args past the variable's context so we
13673 don't replace the auto with an unrelated argument. */
13677 /* This should never happen with the new lambda instantiation
13678 model, but keep the handling just in case. */
13681 }
13683 }
13685 {
13686 /* Even if the original location is out of scope, the
13687 newly substituted one is not. */
13694 {
13695 /* It may seem that this case cannot occur, since:
13697 typedef void f();
13698 void g() { f x; }
13700 declares a function, not a variable. However:
13702 typedef void f();
13703 template <typename T> void g() { T t; }
13704 template void g<f>();
13706 is an attempt to declare a variable with function
13707 type. */
13709 /* R is not yet sufficiently initialized, so we
13710 just use its name. */
13713 }
13715 /* Wait until cp_finish_decl to set this again, to handle
13716 circular dependency (template/instantiate6.C). */
13721 {
13726 {
13729 }
13731 }
13735 }
13741 /* Clear out the mangled name and RTL for the instantiation. */
13745 /* The initializer must not be expanded until it is required;
13746 see [temp.inst]. */
13750 {
13756 /* Possibly limit visibility based on template args. */
13759 {
13763 }
13765 }
13768 {
13769 /* A static data member declaration is always marked
13770 external when it is declared in-class, even if an
13771 initializer is present. We mimic the non-template
13772 processing here. */
13780 }
13781 else
13782 {
13787 }
13795 /* Preserve a typedef that names a type. */
13797 {
13801 /* An alias template specialization can be dependent
13802 even if its underlying type is not. */
13804 }
13807 }
13812 }
13813 #undef RETURN
13815 out:
13816 /* Restore the file and line information. */
13820 }
13822 /* Substitute into the ARG_TYPES of a function type.
13823 If END is a TREE_CHAIN, leave it and any following types
13824 un-substituted. */
13826 static tree
13828 tree args,
13829 tree end,
13830 tsubst_flags_t complain,
13831 tree in_decl)
13832 {
13833 tree remaining_arg_types;
13837 tree default_arg;
13848 {
13849 /* For a pack expansion, perform substitution on the
13850 entire expression. Later on, we'll handle the arguments
13851 one-by-one. */
13856 /* So that we'll spin through the parameters, one by one. */
13858 else
13859 {
13860 /* We only partially substituted into the parameter
13861 pack. Our type is TYPE_PACK_EXPANSION. */
13864 }
13865 }
13878 {
13880 {
13884 }
13886 }
13887 /* DR 657. */
13891 /* Do array-to-pointer, function-to-pointer conversion, and ignore
13892 top-level qualifiers as required. */
13895 /* We do not substitute into default arguments here. The standard
13896 mandates that they be instantiated only when needed, which is
13897 done in build_over_call. */
13900 /* Except that we do substitute default arguments under tsubst_lambda_expr,
13901 since the new op() won't have any associated template arguments for us
13902 to refer to later. */
13908 {
13909 /* We've instantiated a template before its default arguments
13910 have been parsed. This can happen for a nested template
13911 class, and is not an error unless we require the default
13912 argument in a call of this function. */
13913 remaining_arg_types =
13916 }
13917 else
13918 remaining_arg_types =
13920 }
13923 }
13925 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
13926 *not* handle the exception-specification for FNTYPE, because the
13927 initial substitution of explicitly provided template parameters
13928 during argument deduction forbids substitution into the
13929 exception-specification:
13931 [temp.deduct]
13933 All references in the function type of the function template to the
13934 corresponding template parameters are replaced by the specified tem-
13935 plate argument values. If a substitution in a template parameter or
13936 in the function type of the function template results in an invalid
13937 type, type deduction fails. [Note: The equivalent substitution in
13938 exception specifications is done only when the function is instanti-
13939 ated, at which point a program is ill-formed if the substitution
13940 results in an invalid type.] */
13942 static tree
13944 tree args,
13945 tsubst_flags_t complain,
13946 tree in_decl)
13947 {
13948 tree return_type;
13950 tree fntype;
13952 /* The TYPE_CONTEXT is not used for function/method types. */
13955 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
13956 failure. */
13960 {
13961 /* Substitute the argument types. */
13973 {
13974 /* DR 1207: 'this' is in scope in the trailing return type. */
13976 }
13978 /* Substitute the return type. */
13982 {
13985 }
13986 }
13987 else
13988 /* Substitute the return type. */
13993 /* DR 486 clarifies that creation of a function type with an
13994 invalid return type is a deduction failure. */
13997 {
13999 {
14002 else
14004 }
14006 }
14007 /* And DR 657. */
14012 {
14013 /* Substitute the argument types. */
14018 }
14020 /* Construct a new type node and return it. */
14022 {
14027 }
14028 else
14029 {
14031 /* Don't pick up extra function qualifiers from the basetype. */
14034 {
14035 /* [temp.deduct]
14037 Type deduction may fail for any of the following
14038 reasons:
14040 -- Attempting to create "pointer to member of T" when T
14041 is not a class type. */
14044 r);
14046 }
14051 }
14058 }
14060 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
14061 ARGS into that specification, and return the substituted
14062 specification. If there is no specification, return NULL_TREE. */
14064 static tree
14066 tree args,
14067 tsubst_flags_t complain,
14068 tree in_decl,
14070 {
14071 tree specs;
14072 tree new_specs;
14077 {
14078 /* A noexcept-specifier. */
14083 {
14084 /* Defer instantiation of noexcept-specifiers to avoid
14085 excessive instantiations (c++/49107). */
14088 {
14089 /* We already partially instantiated this member template,
14090 so combine the new args with the old. */
14095 }
14096 else
14097 {
14100 }
14101 }
14102 else
14103 new_specs = tsubst_copy_and_build
14107 }
14109 {
14112 else
14114 {
14115 tree spec;
14120 {
14121 /* Expand the pack expansion type. */
14124 in_decl);
14130 else
14131 {
14132 /* We're substituting into a member template, so
14133 we got a TYPE_PACK_EXPANSION back. Add that
14134 expansion and move on. */
14138 expanded_specs,
14139 complain);
14142 }
14143 }
14146 {
14149 else
14154 complain);
14155 }
14158 }
14159 }
14161 }
14163 /* Take the tree structure T and replace template parameters used
14164 therein with the argument vector ARGS. IN_DECL is an associated
14165 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
14166 Issue error and warning messages under control of COMPLAIN. Note
14167 that we must be relatively non-tolerant of extensions here, in
14168 order to preserve conformance; if we allow substitutions that
14169 should not be allowed, we may allow argument deductions that should
14170 not succeed, and therefore report ambiguous overload situations
14171 where there are none. In theory, we could allow the substitution,
14172 but indicate that it should have failed, and allow our caller to
14173 make sure that the right thing happens, but we don't try to do this
14174 yet.
14176 This function is used for dealing with types, decls and the like;
14177 for expressions, use tsubst_expr or tsubst_copy. */
14179 tree
14181 {
14204 else
14209 /* Reuse typedefs. We need to do this to handle dependent attributes,
14210 such as attribute aligned. */
14213 {
14217 {
14218 /* DECL represents an alias template and we want to
14219 instantiate it. */
14223 }
14227 {
14231 }
14236 else
14237 /* The typedef is from a non-template context. */
14241 {
14243 r = cp_build_qualified_type_real
14247 }
14248 else
14249 {
14250 /* We don't have an instantiation yet, so drop the typedef. */
14255 }
14256 }
14273 {
14299 {
14305 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
14306 needed. */
14312 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
14313 with TREE_SIDE_EFFECTS that indicates this is not an integral
14314 constant expression. */
14317 {
14320 }
14323 }
14329 {
14335 /* Early in template argument deduction substitution, we don't
14336 want to reduce the level of 'auto', or it will be confused
14337 with a normal template parm in subsequent deduction. */
14349 {
14352 /* See through ARGUMENT_PACK_SELECT arguments. */
14355 }
14360 {
14362 /* If ARG is an argument pack, we don't actually want to
14363 perform a substitution here, because substitutions
14364 for argument packs are only done
14365 element-by-element. We can get to this point when
14366 substituting the type of a non-type template
14367 parameter pack, when that type actually contains
14368 template parameter packs from an outer template, e.g.,
14370 template<typename... Types> struct A {
14371 template<Types... Values> struct B { };
14372 }; */
14376 {
14382 return cp_build_qualified_type_real
14384 }
14386 {
14387 /* We are processing a type constructed from a
14388 template template parameter. */
14399 /* Consider this code:
14401 template <template <class> class Template>
14402 struct Internal {
14403 template <class Arg> using Bind = Template<Arg>;
14404 };
14406 template <template <class> class Template, class Arg>
14407 using Instantiate = Template<Arg>; //#0
14409 template <template <class> class Template,
14410 class Argument>
14411 using Bind =
14412 Instantiate<Internal<Template>::template Bind,
14413 Argument>; //#1
14415 When #1 is parsed, the
14416 BOUND_TEMPLATE_TEMPLATE_PARM representing the
14417 parameter `Template' in #0 matches the
14418 UNBOUND_CLASS_TEMPLATE representing the argument
14419 `Internal<Template>::template Bind'; We then want
14420 to assemble the type `Bind<Argument>' that can't
14421 be fully created right now, because
14422 `Internal<Template>' not being complete, the Bind
14423 template cannot be looked up in that context. So
14424 we need to "store" `Bind<Argument>' for later
14425 when the context of Bind becomes complete. Let's
14426 store that in a TYPENAME_TYPE. */
14430 argvec),
14431 typename_type,
14432 complain);
14434 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
14435 are resolving nested-types in the signature of a
14436 member function templates. Otherwise ARG is a
14437 TEMPLATE_DECL and is the real template to be
14438 instantiated. */
14446 complain);
14447 return cp_build_qualified_type_real
14449 }
14452 else
14453 /* TEMPLATE_PARM_INDEX. */
14455 }
14458 /* This can happen during the attempted tsubst'ing in
14459 unify. This means that we don't yet have any information
14460 about the template parameter in question. */
14463 /* If we get here, we must have been looking at a parm for a
14464 more deeply nested template. Make a new version of this
14465 template parameter, but with a lower level. */
14467 {
14472 {
14474 r = cp_build_qualified_type_real
14478 }
14485 /* Break infinite recursion when substituting the constraints
14487 else
14488 {
14499 {
14500 /* Propagate constraints on placeholders. */
14505 {
14508 }
14509 }
14512 /* We have reduced the level of the template
14513 template parameter, but not the levels of its
14514 template parameters, so canonical_type_parameter
14515 will not be able to find the canonical template
14516 template parameter for this level. Thus, we
14517 require structural equality checking to compare
14518 TEMPLATE_TEMPLATE_PARMs. */
14522 else
14526 {
14528 /* We might need to substitute into the types of non-type
14529 template parameters. */
14541 }
14542 }
14546 /* OK, now substitute the type of the non-type parameter. We
14547 couldn't do it earlier because it might be an auto parameter,
14548 and we wouldn't need to if we had an argument. */
14557 }
14560 }
14563 {
14571 {
14575 }
14578 {
14582 }
14585 {
14589 }
14595 }
14598 /* We should never be tsubsting a binfo. */
14602 /* A vector of template arguments. */
14608 {
14612 /* [temp.deduct]
14614 Type deduction may fail for any of the following
14615 reasons:
14617 -- Attempting to create a pointer to reference type.
14618 -- Attempting to create a reference to a reference type or
14619 a reference to void.
14621 Core issue 106 says that creating a reference to a reference
14622 during instantiation is no longer a cause for failure. We
14623 only enforce this check in strict C++98 mode. */
14627 {
14630 /* We keep track of the last time we issued this error
14631 message to avoid spewing a ton of messages during a
14632 single bad template instantiation. */
14635 {
14640 else
14643 }
14646 }
14650 {
14652 {
14655 type);
14656 else
14658 type);
14659 }
14661 }
14663 {
14667 }
14669 /* In C++0x, during template argument substitution, when there is an
14670 attempt to create a reference to a reference type, reference
14671 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
14673 "If a template-argument for a template-parameter T names a type
14674 that is a reference to a type A, an attempt to create the type
14675 'lvalue reference to cv T' creates the type 'lvalue reference to
14676 A,' while an attempt to create the type type rvalue reference to
14677 cv T' creates the type T"
14678 */
14679 r = cp_build_reference_type
14682 else
14687 /* Will this ever be needed for TYPE_..._TO values? */
14691 }
14693 {
14696 {
14697 /* [temp.deduct]
14699 Type deduction may fail for any of the following
14700 reasons:
14702 -- Attempting to create "pointer to member of T" when T
14703 is not a class type. */
14707 }
14709 {
14713 }
14715 {
14719 }
14722 {
14723 /* The type of the implicit object parameter gets its
14724 cv-qualifiers from the FUNCTION_TYPE. */
14725 tree memptr;
14726 tree method_type
14731 complain);
14732 }
14733 else
14736 complain);
14737 }
14740 {
14741 tree fntype;
14742 tree specs;
14747 /* Substitute the exception specification. */
14755 }
14757 {
14762 /* As an optimization, we avoid regenerating the array type if
14763 it will obviously be the same as T. */
14767 /* These checks should match the ones in create_array_type_for_decl.
14769 [temp.deduct]
14771 The deduction may fail for any of the following reasons:
14773 -- Attempting to create an array with an element type that
14774 is void, a function type, or a reference type, or [DR337]
14775 an abstract class type. */
14781 {
14785 }
14793 {
14796 }
14799 }
14802 {
14814 {
14818 }
14820 {
14821 /* Normally, make_typename_type does not require that the CTX
14822 have complete type in order to allow things like:
14824 template <class T> struct S { typename S<T>::X Y; };
14826 But, such constructs have already been resolved by this
14827 point, so here CTX really should have complete type, unless
14828 it's a partial instantiation. */
14831 {
14835 }
14836 }
14843 {
14846 }
14849 {
14851 {
14855 else
14857 }
14859 {
14863 else
14865 }
14866 }
14868 return cp_build_qualified_type_real
14870 }
14873 {
14885 }
14888 {
14889 tree type;
14905 complain);
14906 }
14909 {
14910 tree type;
14921 {
14923 {
14927 }
14930 }
14941 else
14942 {
14946 /* In a template ~id could be either a complement expression
14947 or an unqualified-id naming a destructor; if instantiating
14948 it produces an expression, it's not an id-expression or
14949 member access. */
14952 }
14957 }
14960 {
14964 }
14968 {
14969 tree r;
14973 else
14981 }
14996 /* We should use one of the expression tsubsts for these codes. */
15002 }
15003 }
15005 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
15006 expression on the left-hand side of the "." or "->" operator. We
15007 only do the lookup if we had a dependent BASELINK. Otherwise we
15008 adjust it onto the instantiated heirarchy. */
15010 static tree
15013 {
15025 {
15032 }
15039 {
15045 /* Treat as-if non-dependent below. */
15050 {
15056 }
15060 }
15061 else
15062 /* We're going to overwrite pieces below, make a duplicate. */
15065 /* If lookup found a single function, mark it as used at this point.
15066 (If lookup found multiple functions the one selected later by
15067 overload resolution will be marked as used at that point.) */
15069 {
15075 /* We might have instantiated an auto function. */
15077 }
15080 {
15081 /* Add back the template arguments, if present. */
15086 /* Update the conversion operator type. */
15088 }
15094 {
15096 qualifying_scope,
15097 object_type);
15099 /* We need to call adjust_result_of_qualified_name_lookup in case the
15100 destructor names a base class, but we unset BASELINK_QUALIFIED_P
15101 so that we still get virtual function binding. */
15103 }
15106 }
15108 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
15109 true if the qualified-id will be a postfix-expression in-and-of
15110 itself; false if more of the postfix-expression follows the
15111 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
15112 of "&". */
15114 static tree
15118 {
15119 tree expr;
15120 tree scope;
15121 tree name;
15123 tree template_args;
15128 /* Figure out what name to look up. */
15131 {
15141 }
15142 else
15143 {
15146 }
15148 /* Substitute into the qualifying scope. When there are no ARGS, we
15149 are just trying to simplify a non-dependent expression. In that
15150 case the qualifying scope may be dependent, and, in any case,
15151 substituting will not help. */
15154 {
15157 }
15158 else
15162 {
15169 }
15172 {
15174 {
15175 /* A BIT_NOT_EXPR is used to represent a destructor. */
15177 {
15181 }
15182 else
15185 }
15186 else
15190 {
15192 {
15196 }
15198 }
15199 }
15202 {
15204 scope);
15205 /* Remember that there was a reference to this entity. */
15208 }
15211 {
15217 }
15220 {
15221 /* We may be repeating a check already done during parsing, but
15222 if it was well-formed and passed then, it will pass again
15223 now, and if it didn't, we wouldn't have got here. The case
15224 we want to catch is when we couldn't tell then, and can now,
15225 namely when templ prior to substitution was an
15226 identifier. */
15232 complain);
15233 else
15235 }
15241 {
15242 expr = (adjust_result_of_qualified_name_lookup
15244 expr = (finish_qualified_id_expr
15248 }
15250 /* Expressions do not generally have reference type. */
15252 /* However, if we're about to form a pointer-to-member, we just
15253 want the referenced member referenced. */
15261 }
15263 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
15264 initializer, DECL is the substituted VAR_DECL. Other arguments are as
15265 for tsubst. */
15267 static tree
15270 {
15277 {
15278 /* If we had an initializer but it
15279 instantiated to nothing,
15280 value-initialize the object. This will
15281 only occur when the initializer was a
15282 pack expansion where the parameter packs
15283 used in that expansion were of length
15284 zero. */
15286 complain);
15291 }
15294 }
15296 /* Like tsubst, but deals with expressions. This function just replaces
15297 template parms; to finish processing the resultant expression, use
15298 tsubst_copy_and_build or tsubst_expr. */
15300 static tree
15302 {
15304 tree r;
15312 {
15317 {
15318 /* We get here for a use of 'this' in an NSDMI. */
15322 /* This can happen for a parameter name used later in a function
15323 declaration (such as in a late-specified return type). Just
15324 make a dummy decl, since it's only used for its type. */
15327 /* Give it the template pattern as its context; its true context
15328 hasn't been instantiated yet and this is good enough for
15329 mangling. */
15331 }
15340 {
15341 tree enum_type;
15342 tree v;
15346 /* There is no need to substitute into namespace-scope
15347 enumerators. */
15350 /* If ARGS is NULL, then T is known to be non-dependent. */
15354 /* Unfortunately, we cannot just call lookup_name here.
15355 Consider:
15357 template <int I> int f() {
15358 enum E { a = I };
15359 struct S { void g() { E e = a; } };
15360 };
15362 When we instantiate f<7>::S::g(), say, lookup_name is not
15363 clever enough to find f<7>::a. */
15364 enum_type
15374 /* We didn't find the name. That should never happen; if
15375 name-lookup found it during preliminary parsing, we
15376 should find it again here during instantiation. */
15378 }
15383 {
15384 tree ctx;
15389 {
15392 {
15396 }
15398 }
15399 }
15409 {
15412 {
15413 /* First try name lookup to find the instantiation. */
15416 {
15417 /* Make sure that the one we found is the one we want. */
15421 }
15425 else
15426 {
15427 /* This can happen for a variable used in a
15428 late-specified return type of a local lambda, or for a
15429 local static or constant. Building a new VAR_DECL
15430 should be OK in all those cases. */
15433 /* Avoid infinite recursion (79640). */
15436 {
15437 /* We can't call cp_finish_decl, so handle the
15438 initializer by hand. */
15453 }
15460 }
15461 /* Remember this for subsequent uses. */
15464 }
15467 }
15468 else
15478 /* An OVERLOAD will always be a non-dependent overload set; an
15479 overload set from function scope will just be represented with an
15480 IDENTIFIER_NODE, and from class scope with a BASELINK. */
15482 /* We must have marked any lookups as persistent. */
15498 {
15499 /* Template template argument like the following example need
15500 special treatment:
15502 template <template <class> class TT> struct C {};
15503 template <class T> struct D {
15504 template <class U> struct E {};
15505 C<E> c; // #1
15506 };
15507 D<int> d; // #2
15509 We are processing the template argument `E' in #1 for
15510 the template instantiation #2. Originally, `E' is a
15511 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
15512 have to substitute this with one having context `D<int>'. */
15516 {
15517 /* When rewriting a constructor into a deduction guide, a
15518 non-dependent name can become dependent, so memtmpl<args>
15519 becomes context::template memtmpl<args>. */
15523 }
15525 }
15526 else
15527 /* Ordinary template template argument. */
15532 {
15533 /* Handle location wrappers by substituting the wrapped node
15534 first, *then* reusing the resulting type. Doing the type
15535 first ensures that we handle template parameters and
15536 parameter pack expansions. */
15540 }
15550 {
15554 }
15559 {
15568 /* We only want to compute the number of arguments. */
15571 else
15578 {
15580 /* Set TREE_USED for the benefit of -Wunused. */
15584 }
15592 {
15597 else
15603 else
15606 }
15607 else
15609 }
15611 {
15619 }
15620 /* Fall through */
15636 {
15640 }
15643 {
15644 tree object;
15645 tree name;
15650 {
15654 }
15657 {
15667 }
15672 in_decl);
15673 else
15676 }
15714 {
15718 }
15721 {
15726 }
15729 {
15733 }
15736 {
15744 }
15750 {
15757 }
15760 {
15767 }
15770 {
15777 }
15780 {
15781 /* Substituted template arguments */
15790 }
15793 {
15813 }
15838 /* Fall through. */
15841 {
15844 }
15845 else
15849 /* This is handled by tsubst_copy_and_build. */
15853 {
15857 }
15860 /* We shouldn't have built any of these during initial template
15861 generation. Instead, they should be built during instantiation
15862 in response to the saved STMT_IS_FULL_EXPR_P setting. */
15866 {
15876 }
15894 {
15895 /* Instantiate any typedefs in the type. */
15900 }
15903 /* These can sometimes show up in a partial instantiation, but never
15904 involve template parms. */
15920 /* ??? There's no point in copying it for now, but maybe some
15921 day it will contain more information, such as a pointer back
15922 to the containing function, inlined copy or so. */
15926 /* We shouldn't get here, but keep going if !flag_checking. */
15930 }
15931 }
15933 /* Helper function for tsubst_omp_clauses, used for instantiation of
15934 OMP_CLAUSE_DECL of clauses. */
15936 static tree
15938 tree in_decl)
15939 {
15943 /* Handle an OpenMP array section represented as a TREE_LIST (or
15944 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15945 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15946 TREE_LIST. We can handle it exactly the same as an array section
15947 (purpose, value, and a chain), even though the nomenclature
15948 (low_bound, length, etc) is different. */
15950 {
15951 tree low_bound
15957 in_decl);
15966 }
15969 /* Undo convert_from_reference tsubst_expr could have called. */
15975 }
15977 /* Like tsubst_copy, but specifically for OpenMP clauses. */
15979 static tree
15982 {
15987 {
15993 {
15996 {
16002 }
16003 /* FALLTHRU */
16018 in_decl);
16050 {
16053 {
16060 }
16061 else
16063 }
16066 in_decl);
16072 in_decl);
16080 in_decl);
16082 {
16085 }
16090 else
16093 in_decl,
16117 }
16120 {
16130 /* tsubst_expr on SCOPE_REF results in returning
16131 finish_non_static_data_member result. Undo that here. */
16135 {
16140 {
16144 CASE_CONVERT:
16153 /* FALLTHRU */
16157 }
16158 }
16164 {
16167 {
16170 }
16171 }
16175 }
16176 }
16180 {
16185 {
16188 }
16189 }
16191 }
16193 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
16195 static tree
16197 tree in_decl)
16198 {
16199 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
16219 {
16222 else
16223 {
16227 }
16228 }
16233 #undef RECUR
16234 }
16236 /* Used to temporarily communicate the list of #pragma omp parallel
16237 clauses to #pragma omp for instantiation if they are combined
16238 together. */
16242 /* Substitute one OMP_FOR iterator. */
16244 static void
16249 {
16250 #define RECUR(NODE) \
16251 tsubst_expr ((NODE), args, complain, in_decl, \
16252 integral_constant_expression_p)
16259 {
16262 }
16268 {
16269 /* We need to jump through some hoops to handle declarations in the
16270 init-statement, since we might need to handle auto deduction,
16271 but we need to keep control of initialization. */
16275 }
16276 else
16277 {
16279 {
16282 {
16286 {
16290 CASE_CONVERT:
16298 {
16301 }
16302 /* FALLTHRU */
16306 }
16307 }
16308 }
16309 else
16311 }
16322 {
16324 {
16325 /* Declare the variable, but don't let that initialize it. */
16330 }
16335 {
16340 }
16341 else
16348 }
16351 {
16352 /* Declare and initialize the variable. */
16355 }
16357 {
16361 {
16363 {
16369 {
16372 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
16377 }
16380 {
16382 decl);
16384 }
16387 {
16389 decl);
16391 }
16392 else
16394 }
16397 }
16399 {
16404 {
16407 }
16408 }
16409 }
16412 {
16416 }
16417 else
16421 {
16432 {
16440 }
16441 else
16447 {
16453 }
16457 {
16465 }
16466 else
16472 }
16478 #undef RECUR
16479 }
16481 /* Helper function of tsubst_expr, find OMP_TEAMS inside
16482 of OMP_TARGET's body. */
16484 static tree
16486 {
16489 {
16498 }
16500 }
16502 /* Helper function for tsubst_expr. For decomposition declaration
16503 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
16504 also the corresponding decls representing the identifiers
16505 of the decomposition declaration. Return DECL if successful
16506 or error_mark_node otherwise, set *FIRST to the first decl
16507 in the list chained through DECL_CHAIN and *CNT to the number
16508 of such decls. */
16510 static tree
16514 {
16519 decl2
16524 {
16526 {
16529 }
16541 else
16542 {
16546 }
16553 {
16556 }
16557 else
16559 }
16562 }
16564 /* Like tsubst_copy for expressions, etc. but also does semantic
16565 processing. */
16567 tree
16570 {
16571 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
16572 #define RECUR(NODE) \
16573 tsubst_expr ((NODE), args, complain, in_decl, \
16574 integral_constant_expression_p)
16577 tree r;
16578 location_t loc;
16590 {
16592 {
16593 tree_stmt_iterator i;
16597 }
16612 else
16622 {
16624 tree init;
16630 {
16640 else
16642 }
16645 {
16646 /* We're in tsubst_lambda_expr, we've already inserted a new
16647 capture proxy, so look it up and register it. */
16648 tree inst;
16650 {
16651 inst = (retrieve_local_specialization
16654 }
16655 else
16656 {
16660 }
16663 }
16666 /* Don't copy the old closure; we'll create a new one in
16667 tsubst_lambda_expr. */
16669 else
16670 {
16674 {
16675 /* By marking the declaration as instantiated, we avoid
16676 trying to instantiate it. Since instantiate_decl can't
16677 handle local variables, and since we've already done
16678 all that needs to be done, that's the right thing to
16679 do. */
16684 /* Anonymous aggregates are a special case. */
16687 {
16690 {
16694 }
16696 }
16702 {
16707 }
16708 else
16709 {
16714 {
16715 /* For __PRETTY_FUNCTION__ we have to adjust the
16716 initializer. */
16720 }
16721 else
16725 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
16730 {
16732 tree first;
16733 tree ndecl
16741 }
16742 else
16744 }
16745 }
16746 }
16749 }
16759 {
16763 }
16768 {
16769 /* Construct another range_for, if this is not a final
16770 substitution (for inside inside a generic lambda of a
16771 template). Otherwise convert to a regular for. */
16773 stmt = (processing_template_decl
16789 {
16793 }
16794 else
16795 {
16801 }
16807 }
16814 {
16818 }
16824 {
16828 }
16843 {
16844 /* We're partially instantiating a generic lambda, but the condition
16845 of the constexpr if is still dependent. Don't substitute into the
16846 branches now, just remember the template arguments. */
16854 }
16857 else
16858 {
16865 }
16871 {
16880 }
16888 else
16896 else
16917 {
16924 }
16928 {
16930 tree label;
16937 }
16943 /* Computed goto's must be tsubst'd into. On the other hand,
16944 non-computed gotos must not be; the identifier in question
16945 will have no binding. */
16947 else
16953 {
16969 }
16974 {
16979 }
16980 else
16981 {
16986 else
16993 else
16999 else
17001 }
17005 {
17009 {
17011 /* Prevent instantiate_decl from trying to instantiate
17012 this variable. We've already done all that needs to be
17013 done. */
17016 }
17021 }
17027 {
17028 /* Local classes are not independent templates; they are
17029 instantiated along with their containing function. And this
17030 way we don't have to deal with pushing out of one local class
17031 to instantiate a member of another local class. */
17032 /* Closures are handled by the LAMBDA_EXPR. */
17042 }
17046 {
17047 tree condition;
17050 condition =
17052 args,
17061 }
17067 in_decl);
17102 {
17115 in_decl);
17117 {
17124 }
17136 integral_constant_expression_p);
17147 else
17148 {
17156 }
17160 }
17165 /* FALLTHRU */
17172 in_decl);
17189 in_decl);
17200 {
17203 {
17204 /* For combined target teams, ensure the num_teams and
17205 thread_limit clause expressions are evaluated on the host,
17206 before entering the target construct. */
17207 tree c;
17213 {
17222 OMP_CLAUSE_FIRSTPRIVATE);
17226 }
17227 }
17228 }
17288 {
17293 {
17296 }
17302 }
17303 else
17304 {
17311 {
17314 }
17317 {
17322 {
17325 }
17331 }
17332 else
17333 {
17337 }
17340 }
17344 {
17350 {
17354 {
17359 }
17363 }
17364 else
17365 {
17370 }
17371 }
17375 {
17379 }
17392 /* If the first operand was a statement, we're done with it. */
17396 complain));
17410 integral_constant_expression_p));
17411 }
17414 out:
17417 #undef RECUR
17418 #undef RETURN
17419 }
17421 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
17422 function. For description of the body see comment above
17423 cp_parser_omp_declare_reduction_exprs. */
17425 static void
17427 {
17433 tree_stmt_iterator tsi;
17444 {
17463 }
17465 {
17485 }
17486 }
17488 /* T is a postfix-expression that is not being used in a function
17489 call. Return the substituted version of T. */
17491 static tree
17493 tsubst_flags_t complain,
17494 tree in_decl)
17495 {
17499 else
17505 }
17507 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
17508 instantiation context. Instantiating a pack expansion containing a lambda
17509 might result in multiple lambdas all based on the same lambda in the
17510 template. */
17512 tree
17514 {
17528 else
17536 {
17548 else
17553 {
17562 }
17563 else
17564 {
17570 }
17571 }
17577 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
17595 else
17596 {
17597 /* Fix the type of 'this'. */
17603 {
17607 }
17608 else
17609 {
17613 }
17615 /* Let finish_function set this. */
17621 else
17622 /* Still increment function_depth so that we don't GC in the
17623 middle of an expression. */
17639 else
17642 /* The capture list was built up in reverse order; fix that now. */
17649 }
17656 }
17658 /* Like tsubst but deals with expressions and performs semantic
17659 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
17661 tree
17663 tree args,
17664 tsubst_flags_t complain,
17665 tree in_decl,
17668 {
17669 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
17670 #define RECUR(NODE) \
17671 tsubst_copy_and_build (NODE, args, complain, in_decl, \
17673 integral_constant_expression_p)
17676 location_t loc;
17685 /* N3276 decltype magic only applies to calls at the top level or on the
17686 right side of a comma. */
17691 {
17694 /* Fall through. */
17696 {
17697 tree decl;
17698 cp_id_kind idk;
17703 {
17706 }
17708 /* Look up the name. */
17711 /* By convention, expressions use ERROR_MARK_NODE to indicate
17712 failure, not NULL_TREE. */
17718 integral_constant_expression_p,
17726 input_location);
17730 {
17734 }
17736 }
17739 {
17740 tree object;
17750 {
17755 }
17761 {
17764 }
17765 else
17772 else
17774 }
17777 {
17781 {
17782 /* A type conversion to reference type will be enclosed in
17783 such an indirect ref, but the substitution of the cast
17784 will have also added such an indirect ref. */
17786 }
17787 else
17795 }
17798 {
17802 }
17805 {
17809 {
17814 }
17816 /* We'll pass this to convert_nontype_argument again, we don't need
17817 to actually perform any conversion here. */
17823 flags));
17824 }
17827 {
17833 }
17840 {
17841 tree type;
17847 {
17852 }
17859 {
17877 }
17880 }
17913 else
17915 in_decl);
17950 {
17957 tree r = build_x_binary_op
17959 op0,
17961 ? ERROR_MARK
17963 op1,
17965 ? ERROR_MARK
17973 }
17976 {
17980 }
17996 /* Fall through */
17999 {
18000 tree r;
18006 {
18007 /* When there are no ARGS, we are trying to evaluate a
18008 non-dependent expression from the parser. Trying to do
18009 the substitutions may not work. */
18012 }
18013 else
18014 {
18019 else
18022 /*integral_constant_expression_p=*/
18026 }
18030 else
18034 {
18036 {
18038 {
18042 }
18043 else
18047 }
18049 }
18051 }
18054 {
18064 }
18080 {
18084 tree r = build_x_modify_expr
18087 /* TREE_NO_WARNING must be set if either the expression was
18088 parenthesized or it uses an operator such as >>= rather
18089 than plain assignment. In the former case, it was already
18090 set and must be copied. In the latter case,
18091 build_x_modify_expr sets it and it must not be reset
18092 here. */
18097 }
18102 /* Remember that there was a reference to this entity. */
18109 {
18114 tree ret;
18118 else
18119 {
18123 }
18125 /* If there was an initializer in the original tree, but it
18126 instantiated to an empty list, then we should pass a
18127 non-NULL empty vector to tell build_new that it was an
18128 empty initializer() rather than no initializer. This can
18129 only happen when the initializer is a pack expansion whose
18130 parameter packs are of length zero. */
18133 else
18134 {
18138 else
18139 {
18142 }
18143 }
18149 complain);
18157 }
18160 {
18166 complain));
18167 }
18170 {
18174 integral_constant_expression_p);
18176 op0,
18179 }
18182 {
18183 tree function;
18188 tree ret;
18191 /* Internal function with no arguments. */
18195 /* When we parsed the expression, we determined whether or
18196 not Koenig lookup should be performed. */
18199 {
18202 }
18204 {
18209 }
18211 {
18212 /* Do nothing; calling tsubst_copy_and_build on an identifier
18213 would incorrectly perform unqualified lookup again.
18215 Note that we can also have an IDENTIFIER_NODE if the earlier
18216 unqualified lookup found a member function; in that case
18217 koenig_p will be false and we do want to do the lookup
18218 again to find the instantiated member function.
18220 FIXME but doing that causes c++/15272, so we need to stop
18221 using IDENTIFIER_NODE in that situation. */
18223 }
18224 else
18225 {
18227 {
18233 }
18234 else
18239 /* Avoid error about taking the address of a constructor. */
18243 in_decl,
18245 integral_constant_expression_p);
18249 }
18254 {
18259 else
18260 {
18261 /* Expand the pack expansion and push each entry onto
18262 CALL_ARGS. */
18265 {
18270 {
18275 }
18276 }
18277 else
18278 {
18279 /* A partial substitution. Add one entry. */
18281 }
18282 }
18283 }
18285 /* We do not perform argument-dependent lookup if normal
18286 lookup finds a non-function, in accordance with the
18287 expected resolution of DR 218. */
18290 /* If lookup found a member function, the Koenig lookup is
18291 not appropriate, even if an unqualified-name was used
18292 to denote the function. */
18295 /* Only do this when substitution turns a dependent call
18296 into a non-dependent call. */
18304 {
18306 {
18307 /* For backwards compatibility and good diagnostics, try
18308 the unqualified lookup again if we aren't in SFINAE
18309 context. */
18310 tree unq = (tsubst_copy_and_build
18312 integral_constant_expression_p));
18314 {
18317 }
18320 {
18321 /* In a lambda fn, we have to be careful to not
18322 introduce new this captures. Legacy code can't
18323 be using lambdas anyway, so it's ok to be
18324 stricter. */
18329 "and no declarations were found by "
18330 "argument-dependent lookup at the point "
18337 else
18341 {
18352 {
18354 input_location);
18356 "declarations in dependent base %qT are "
18362 else
18366 }
18367 else
18369 "%qD declared here, later in the "
18372 {
18375 }
18376 }
18379 }
18380 }
18382 {
18387 }
18388 }
18390 /* Remember that there was a reference to this entity. */
18394 {
18397 }
18399 /* Put back tf_decltype for the actual call. */
18404 {
18408 {
18410 "wrong number of arguments to "
18413 }
18414 else
18416 input_location),
18421 /* Unsupported internal function with arguments. */
18423 }
18426 complain);
18428 {
18443 complain);
18444 else
18445 ret = (build_new_method_call
18450 complain));
18451 }
18452 else
18455 koenig_p,
18456 complain);
18461 {
18467 {
18473 {
18476 else
18478 /* The thunk location is not interesting. */
18480 }
18481 }
18482 }
18485 }
18488 {
18494 {
18496 {
18501 }
18502 else
18503 {
18508 }
18510 }
18511 else
18512 {
18515 }
18520 }
18523 {
18528 input_location));
18529 }
18532 {
18540 {
18541 /* We have pack expansions, so expand those and
18542 create a new list out of it. */
18545 tree chain;
18548 /* Expand the argument expressions. */
18556 /* Build the rest of the list. */
18561 /* Determine the number of arguments. */
18563 {
18566 }
18569 else
18570 {
18571 /* Since we only performed a partial substitution into
18572 the argument pack, we only RETURN (a single list
18573 node. */
18580 }
18582 /* Convert the argument vectors into a TREE_LIST */
18585 {
18586 /* Grab the Ith values. */
18587 i--;
18590 value
18594 /* Build the list (backwards). */
18596 }
18599 }
18615 }
18618 {
18619 tree object;
18620 tree object_type;
18621 tree member;
18622 tree r;
18626 /* Remember that there was a reference to this entity. */
18637 else
18643 {
18648 }
18652 {
18654 {
18659 {
18662 }
18664 {
18669 }
18670 }
18671 }
18674 {
18675 /* Lookup the template functions now that we know what the
18676 scope is. */
18684 {
18687 args);
18688 member = (adjust_result_of_qualified_name_lookup
18690 object_type));
18691 }
18692 else
18693 {
18695 input_location);
18697 }
18698 }
18702 {
18704 {
18708 else
18711 }
18713 }
18717 complain);
18721 }
18728 {
18736 tree r;
18741 /* We do not want to process the index of aggregate
18742 initializers as they are identifier nodes which will be
18743 looked up by digest_init. */
18749 {
18751 /* An identifier index is looked up in the type
18752 being initialized, not the current scope. */
18757 {
18758 /* Substitute into the pack expansion. */
18760 in_decl);
18764 ;
18766 /* Just move the argument into place. */
18768 else
18769 {
18770 /* Update the length of the final CONSTRUCTOR
18771 arguments vector, and note that we will need to
18772 copy.*/
18775 }
18776 }
18777 else
18779 }
18782 {
18787 {
18789 {
18794 }
18795 else
18797 }
18798 }
18804 {
18809 }
18813 }
18816 {
18819 {
18822 }
18823 else
18824 {
18827 }
18828 }
18833 /* Fall through */
18836 {
18838 /* ??? We're doing a subset of finish_id_expression here. */
18840 && !processing_template_decl
18841 && !cp_unevaluated_operand
18844 {
18846 /* Replace an evaluated use of the thread_local variable with
18847 a call to its wrapper. */
18849 }
18854 /* If the original type was a reference, we'll be wrapped in
18855 the appropriate INDIRECT_REF. */
18858 }
18861 {
18865 }
18868 {
18869 tree object_ptr
18876 }
18883 {
18894 }
18897 {
18903 integral_constant_expression_p);
18907 /* If the resulting list of expression statement is empty,
18908 fold it further into void_node. */
18913 }
18916 {
18920 }
18923 /* We can get here for a constant initializer of non-dependent type.
18924 FIXME stop folding in cp_parser_initializer_clause. */
18925 {
18927 complain);
18929 }
18933 integral_constant_expression_p));
18939 {
18944 complain));
18945 }
18952 /* We should only see these for location wrapper nodes, or within
18953 instantiate_non_dependent_expr (when args is NULL_TREE). */
18958 /* fallthrough. */
18961 /* Handle Objective-C++ constructs, if appropriate. */
18962 {
18963 tree subst
18968 }
18970 }
18972 #undef RECUR
18973 #undef RETURN
18974 out:
18977 }
18979 /* Verify that the instantiated ARGS are valid. For type arguments,
18980 make sure that the type's linkage is ok. For non-type arguments,
18981 make sure they are constants if they are integral or enumerations.
18982 Emit an error under control of COMPLAIN, and return TRUE on error. */
18984 static bool
18986 {
18990 {
19000 }
19002 {
19003 /* [basic.link]: A name with no linkage (notably, the name
19004 of a class or enumeration declared in a local scope)
19005 shall not be used to declare an entity with linkage.
19006 This implies that names with no linkage cannot be used as
19007 template arguments
19009 DR 757 relaxes this restriction for C++0x. */
19014 {
19015 /* DR 488 makes use of a type with no linkage cause
19016 type deduction to fail. */
19018 {
19021 else
19024 }
19026 }
19027 /* In order to avoid all sorts of complications, we do not
19028 allow variably-modified types as template arguments. */
19030 {
19034 }
19035 }
19036 /* Class template and alias template arguments should be OK. */
19038 ;
19039 /* A non-type argument of integral or enumerated type must be a
19040 constant. */
19045 {
19049 }
19051 }
19053 static bool
19055 {
19060 {
19063 }
19067 }
19069 /* We're out of SFINAE context now, so generate diagnostics for the access
19070 errors we saw earlier when instantiating D from TMPL and ARGS. */
19072 static void
19074 {
19086 }
19088 /* Instantiate the indicated variable, function, or alias template TMPL with
19089 the template arguments in TARG_PTR. */
19091 static tree
19093 {
19095 tree fndecl;
19096 tree gen_tmpl;
19097 tree spec;
19105 /* If this function is a clone, handle it specially. */
19107 {
19108 tree spec;
19109 tree clone;
19111 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
19112 DECL_CLONED_FUNCTION. */
19118 /* Look for the clone. */
19122 /* We should always have found the clone by now. */
19125 }
19130 /* Check to see if we already have this specialization. */
19134 /* targ_ptr only has the innermost template args, so add the outer ones
19135 from tmpl, which could be either a partial instantiation or gen_tmpl (in
19136 the case of a non-dependent call within a template definition). */
19137 targ_ptr = (add_outermost_template_args
19139 targ_ptr));
19141 /* It would be nice to avoid hashing here and then again in tsubst_decl,
19142 but it doesn't seem to be on the hot path. */
19151 {
19153 {
19157 }
19159 }
19162 complain))
19165 /* We are building a FUNCTION_DECL, during which the access of its
19166 parameters and return types have to be checked. However this
19167 FUNCTION_DECL which is the desired context for access checking
19168 is not built yet. We solve this chicken-and-egg problem by
19169 deferring all checks until we have the FUNCTION_DECL. */
19172 /* Instantiation of the function happens in the context of the function
19173 template, not the context of the overload resolution we're doing. */
19175 /* If there are dependent arguments, e.g. because we're doing partial
19176 ordering, make sure processing_template_decl stays set. */
19180 {
19184 }
19190 {
19191 /* We need to determine if we're using a partial or explicit
19192 specialization now, because the type of the variable could be
19193 different. */
19199 {
19204 }
19205 }
19207 /* Substitute template parameters to obtain the specialization. */
19215 {
19218 }
19220 /* The DECL_TI_TEMPLATE should always be the immediate parent
19221 template, not the most general template. */
19225 /* Now we know the specialization, compute access previously
19226 deferred. Do no access control for inheriting constructors,
19227 as we already checked access for the inherited constructor. */
19230 {
19235 }
19238 /* If we've just instantiated the main entry point for a function,
19239 instantiate all the alternate entry points as well. We do this
19240 by cloning the instantiation of the main entry point, not by
19241 instantiating the template clones. */
19246 {
19248 {
19249 /* Remember to reinstantiate when we're out of SFINAE so the user
19250 can see the errors. */
19252 }
19254 }
19256 }
19258 /* Wrapper for instantiate_template_1. */
19260 tree
19262 {
19263 tree ret;
19268 }
19270 /* Instantiate the alias template TMPL with ARGS. Also push a template
19271 instantiation level, which instantiate_template doesn't do because
19272 functions and variables have sufficient context established by the
19273 callers. */
19275 static tree
19277 {
19283 args =
19293 }
19295 /* PARM is a template parameter pack for FN. Returns true iff
19296 PARM is used in a deducible way in the argument list of FN. */
19298 static bool
19300 {
19303 {
19305 tree packs;
19311 {
19312 /* The template parameter pack is used in a function parameter
19313 pack. If this is the end of the parameter list, the
19314 template parameter pack is deducible. */
19317 else
19318 /* Otherwise, not. Well, it could be deduced from
19319 a non-pack parameter, but doing so would end up with
19320 a deduction mismatch, so don't bother. */
19322 }
19323 }
19324 /* The template parameter pack isn't used in any function parameter
19325 packs, but it might be used deeper, e.g. tuple<Args...>. */
19327 }
19329 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
19330 NARGS elements of the arguments that are being used when calling
19331 it. TARGS is a vector into which the deduced template arguments
19332 are placed.
19334 Returns either a FUNCTION_DECL for the matching specialization of FN or
19335 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
19336 true, diagnostics will be printed to explain why it failed.
19338 If FN is a conversion operator, or we are trying to produce a specific
19339 specialization, RETURN_TYPE is the return type desired.
19341 The EXPLICIT_TARGS are explicit template arguments provided via a
19342 template-id.
19344 The parameter STRICT is one of:
19346 DEDUCE_CALL:
19347 We are deducing arguments for a function call, as in
19348 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
19349 deducing arguments for a call to the result of a conversion
19350 function template, as in [over.call.object].
19352 DEDUCE_CONV:
19353 We are deducing arguments for a conversion function, as in
19354 [temp.deduct.conv].
19356 DEDUCE_EXACT:
19357 We are deducing arguments when doing an explicit instantiation
19358 as in [temp.explicit], when determining an explicit specialization
19359 as in [temp.expl.spec], or when taking the address of a function
19360 template, as in [temp.deduct.funcaddr]. */
19362 tree
19364 tree explicit_targs,
19365 tree targs,
19368 tree return_type,
19369 unification_kind_t strict,
19373 {
19374 tree parms;
19375 tree fntype;
19391 full_targs = (add_outermost_template_args
19393 targs));
19398 /* In C++0x, it's possible to have a function template whose type depends
19399 on itself recursively. This is most obvious with decltype, but can also
19400 occur with enumeration scope (c++/48969). So we need to catch infinite
19401 recursion and reject the substitution at deduction time; this function
19402 will return error_mark_node for any repeated substitution.
19404 This also catches excessive recursion such as when f<N> depends on
19405 f<N-1> across all integers, and returns error_mark_node for all the
19406 substitutions back up to the initial one.
19408 This is, of course, not reentrant. */
19417 {
19418 /* [temp.deduct]
19420 The specified template arguments must match the template
19421 parameters in kind (i.e., type, nontype, template), and there
19422 must not be more arguments than there are parameters;
19423 otherwise type deduction fails.
19425 Nontype arguments must match the types of the corresponding
19426 nontype template parameters, or must be convertible to the
19427 types of the corresponding nontype parameters as specified in
19428 _temp.arg.nontype_, otherwise type deduction fails.
19430 All references in the function type of the function template
19431 to the corresponding template parameters are replaced by the
19432 specified template argument values. If a substitution in a
19433 template parameter or in the function type of the function
19434 template results in an invalid type, type deduction fails. */
19445 explicit_targs);
19447 /* Adjust any explicit template arguments before entering the
19448 substitution context. */
19449 explicit_targs
19451 complain,
19457 /* Substitute the explicit args into the function type. This is
19458 necessary so that, for instance, explicitly declared function
19459 arguments can match null pointed constants. If we were given
19460 an incomplete set of explicit args, we must not do semantic
19461 processing during substitution as we could create partial
19462 instantiations. */
19464 {
19469 /* Dig out the actual parm. */
19472 {
19475 }
19477 {
19480 }
19483 /* No explicit argument for this template parameter. */
19487 {
19488 /* Mark the argument pack as "incomplete". We could
19489 still deduce more arguments during unification.
19490 We remove this mark in type_unification_real. */
19492 {
19496 }
19498 /* We have some incomplete argument packs. */
19500 }
19501 }
19504 {
19507 }
19510 /* Ignore any access checks; we'll see them again in
19511 instantiate_template and they might have the wrong
19512 access path at this point. */
19524 /* Place the explicitly specified arguments in TARGS. */
19528 }
19530 /* Never do unification on the 'this' parameter. */
19534 {
19535 /* We're deducing for a call to the result of a template conversion
19536 function. The parms we really want are in return_type. */
19540 }
19542 {
19551 }
19553 /* We allow incomplete unification without an error message here
19554 because the standard doesn't seem to explicitly prohibit it. Our
19555 callers must be ready to deal with unification failures in any
19556 event. */
19558 /* If we aren't explaining yet, push tinst context so we can see where
19559 any errors (e.g. from class instantiations triggered by instantiation
19560 of default template arguments) come from. If we are explaining, this
19561 context is redundant. */
19563 {
19566 }
19568 /* type_unification_real will pass back any access checks from default
19569 template argument substitution. */
19581 /* Now that we have bindings for all of the template arguments,
19582 ensure that the arguments deduced for the template template
19583 parameters have compatible template parameter lists. We cannot
19584 check this property before we have deduced all template
19585 arguments, because the template parameter types of a template
19586 template parameter might depend on prior template parameters
19587 deduced after the template template parameter. The following
19588 ill-formed example illustrates this issue:
19590 template<typename T, template<T> class C> void f(C<5>, T);
19592 template<int N> struct X {};
19594 void g() {
19595 f(X<5>(), 5l); // error: template argument deduction fails
19596 }
19598 The template parameter list of 'C' depends on the template type
19599 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
19600 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
19601 time that we deduce 'C'. */
19604 {
19607 }
19609 /* All is well so far. Now, check:
19611 [temp.deduct]
19613 When all template arguments have been deduced, all uses of
19614 template parameters in nondeduced contexts are replaced with
19615 the corresponding deduced argument values. If the
19616 substitution results in an invalid type, as described above,
19617 type deduction fails. */
19619 {
19622 }
19624 /* Also collect access checks from the instantiation. */
19637 /* Now perform any access checks encountered during substitution. */
19644 /* If we're looking for an exact match, check that what we got
19645 is indeed an exact match. It might not be if some template
19646 parameters are used in non-deduced contexts. But don't check
19647 for an exact match if we have dependent template arguments;
19648 in that case we're doing partial ordering, and we already know
19649 that we have two candidates that will provide the actual type. */
19651 {
19655 tree sarg
19661 {
19665 }
19666 }
19668 /* After doing deduction with the inherited constructor, actually return an
19669 instantiation of the inheriting constructor. */
19675 fail:
19678 {
19680 /* Reset once we're all the way out. */
19682 }
19685 }
19687 /* Adjust types before performing type deduction, as described in
19688 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
19689 sections are symmetric. PARM is the type of a function parameter
19690 or the return type of the conversion function. ARG is the type of
19691 the argument passed to the call, or the type of the value
19692 initialized with the result of the conversion function.
19693 ARG_EXPR is the original argument expression, which may be null. */
19695 static int
19699 tree arg_expr)
19700 {
19704 {
19709 /* Swap PARM and ARG throughout the remainder of this
19710 function; the handling is precisely symmetric since PARM
19711 will initialize ARG rather than vice versa. */
19716 /* Core issue #873: Do the DR606 thing (see below) for these cases,
19717 too, but here handle it by stripping the reference from PARM
19718 rather than by adding it to ARG. */
19726 /* Nothing else to do in this case. */
19731 }
19734 {
19735 /* [temp.deduct.call]
19737 If P is not a reference type:
19739 --If A is an array type, the pointer type produced by the
19740 array-to-pointer standard conversion (_conv.array_) is
19741 used in place of A for type deduction; otherwise,
19743 --If A is a function type, the pointer type produced by
19744 the function-to-pointer standard conversion
19745 (_conv.func_) is used in place of A for type deduction;
19746 otherwise,
19748 --If A is a cv-qualified type, the top level
19749 cv-qualifiers of A's type are ignored for type
19750 deduction. */
19755 else
19757 }
19759 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
19760 reference to a cv-unqualified template parameter that does not represent a
19761 template parameter of a class template (during class template argument
19762 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
19763 an lvalue, the type "lvalue reference to A" is used in place of A for type
19764 deduction. */
19771 /* try_one_overload doesn't provide an arg_expr, but
19772 functions are always lvalues. */
19776 /* [temp.deduct.call]
19778 If P is a cv-qualified type, the top level cv-qualifiers
19779 of P's type are ignored for type deduction. If P is a
19780 reference type, the type referred to by P is used for
19781 type deduction. */
19784 {
19787 }
19789 /* DR 322. For conversion deduction, remove a reference type on parm
19790 too (which has been swapped into ARG). */
19795 }
19797 /* Subroutine of unify_one_argument. PARM is a function parameter of a
19798 template which does contain any deducible template parameters; check if
19799 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
19800 unify_one_argument. */
19802 static int
19805 {
19806 tree type;
19810 else
19817 {
19821 }
19823 {
19828 }
19832 else
19834 }
19838 /* Returns true iff the expression EXPR is one from which a template
19839 argument can be deduced. In other words, if it's an undecorated
19840 use of a template non-type parameter. */
19842 static bool
19844 {
19845 /* Strip implicit conversions. */
19849 }
19851 /* Returns true iff the array domain DOMAIN uses a template parameter in a
19852 deducible way; that is, if it has a max value of <PARM> - 1. */
19854 static bool
19856 {
19865 }
19867 /* Returns true iff the template arguments ARGS use a template parameter
19868 in a deducible way. */
19870 static bool
19872 {
19874 {
19879 else
19880 {
19887 else
19889 }
19892 }
19894 }
19896 /* Returns true iff TYPE contains any deducible references to template
19897 parameters, as per 14.8.2.5. */
19899 static bool
19901 {
19905 /* T
19906 cv-list T
19907 TT<T>
19908 TT<i>
19909 TT<> */
19914 /* T*
19915 T&
19916 T&& */
19920 /* T[integer-constant ]
19921 type [i] */
19926 /* T type ::*
19927 type T::*
19928 T T::*
19929 T (type ::*)()
19930 type (T::*)()
19931 type (type ::*)(T)
19932 type (T::*)(T)
19933 T (type ::*)(T)
19934 T (T::*)()
19935 T (T::*)(T) */
19938 || (uses_deducible_template_parms
19941 /* template-name <T> (where template-name refers to a class template)
19942 template-name <i> (where template-name refers to a class template) */
19949 /* type (T)
19950 T()
19951 T(T) */
19954 {
19963 }
19966 }
19968 /* Subroutine of type_unification_real and unify_pack_expansion to
19969 handle unification of a single P/A pair. Parameters are as
19970 for those functions. */
19972 static int
19976 {
19983 /* We can't deduce anything from this, but we might get all the
19984 template args from other function args. */
19987 /* Implicit conversions (Clause 4) will be performed on a function
19988 argument to convert it to the type of the corresponding function
19989 parameter if the parameter type contains no template-parameters that
19990 participate in template argument deduction. */
19993 /* For function parameters with no deducible template parameters,
19994 just return. We'll check non-dependent conversions later. */
19998 {
20000 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
20001 | UNIFY_ALLOW_MORE_CV_QUAL
20015 }
20017 /* We only do these transformations if this is the top-level
20018 parameter_type_list in a call or declaration matching; in other
20019 situations (nested function declarators, template argument lists) we
20020 won't be comparing a type to an expression, and we don't do any type
20021 adjustments. */
20023 {
20025 {
20028 {
20029 /* [temp.deduct.type] A template-argument can be
20030 deduced from a pointer to function or pointer
20031 to member function argument if the set of
20032 overloaded functions does not contain function
20033 templates and at most one of a set of
20034 overloaded functions provides a unique
20035 match. */
20039 /* If a unique match was not found, this is a
20040 non-deduced context, so we still succeed. */
20042 }
20048 }
20050 arg_strict |=
20052 }
20053 else
20058 /* For deduction from an init-list we need the actual list. */
20062 }
20064 /* for_each_template_parm callback that always returns 0. */
20066 static int
20068 {
20070 }
20072 /* for_each_template_parm any_fn callback to handle deduction of a template
20073 type argument from the type of an array bound. */
20075 static int
20077 {
20085 {
20091 }
20093 /* Keep walking. */
20095 }
20097 /* Try to deduce any not-yet-deduced template type arguments from the type of
20098 an array bound. This is handled separately from unify because 14.8.2.5 says
20099 "The type of a type parameter is only deduced from an array bound if it is
20100 not otherwise deduced." */
20102 static void
20104 {
20109 }
20111 /* Most parms like fn_type_unification.
20113 If SUBR is 1, we're being called recursively (to unify the
20114 arguments of a function or method parameter of a function
20115 template).
20117 CHECKS is a pointer to a vector of access checks encountered while
20118 substituting default template arguments. */
20120 static int
20122 tree full_targs,
20123 tree xparms,
20127 unification_kind_t strict,
20131 {
20136 tree parms;
20147 /* Reset the number of non-defaulted template arguments contained
20148 in TARGS. */
20151 again:
20159 {
20164 /* For a function parameter pack that occurs at the end of the
20165 parameter-declaration-list, the type A of each remaining
20166 argument of the call is compared with the type P of the
20167 declarator-id of the function parameter pack. */
20173 /* For a function parameter pack that does not occur at the
20174 end of the parameter-declaration-list, the type of the
20175 parameter pack is a non-deduced context. */
20182 explain_p))
20184 }
20189 {
20190 /* Unify the remaining arguments with the pack expansion type. */
20191 tree argvec;
20194 /* Allocate a TREE_VEC and copy in all of the arguments */
20199 /* Copy the parameter into parmvec. */
20205 /* Advance to the end of the list of parameters. */
20207 }
20209 /* Fail if we've reached the end of the parm list, and more args
20210 are present, and the parm list isn't variadic. */
20213 /* Fail if parms are left and they don't have default values and
20214 they aren't all deduced as empty packs (c++/57397). This is
20215 consistent with sufficient_parms_p. */
20218 {
20222 do
20223 {
20226 count++;
20228 }
20232 type_pack_p);
20233 }
20236 {
20237 tsubst_flags_t complain = (explain_p
20238 ? tf_warning_or_error
20243 {
20247 /* Clear the "incomplete" flags on all argument packs now so that
20248 substituting them into later default arguments works. */
20250 {
20253 }
20261 {
20266 }
20268 /* If this is an undeduced nontype parameter that depends on
20269 a type parameter, try another pass; its type may have been
20270 deduced from a later argument than the one from which
20271 this parameter can be deduced. */
20275 {
20278 }
20280 /* Core issue #226 (C++0x) [temp.deduct]:
20282 If a template argument has not been deduced, its
20283 default template argument, if any, is used.
20285 When we are in C++98 mode, TREE_PURPOSE will either
20286 be NULL_TREE or ERROR_MARK_NODE, so we do not need
20287 to explicitly check cxx_dialect here. */
20289 /* OK, there is a default argument. Wait until after the
20290 conversion check to do substitution. */
20293 /* If the type parameter is a parameter pack, then it will
20294 be deduced to an empty parameter pack. */
20296 {
20297 tree arg;
20300 {
20303 }
20304 else
20311 }
20314 }
20316 /* DR 1391: All parameters have args, now check non-dependent parms for
20317 convertibility. */
20321 {
20327 /* For a function parameter pack that occurs at the end of the
20328 parameter-declaration-list, the type A of each remaining
20329 argument of the call is compared with the type P of the
20330 declarator-id of the function parameter pack. */
20336 /* For a function parameter pack that does not occur at the
20337 end of the parameter-declaration-list, the type of the
20338 parameter pack is a non-deduced context. */
20347 explain_p))
20349 }
20351 /* Now substitute into the default template arguments. */
20353 {
20371 {
20372 /* The type of this non-type parameter depends on undeduced
20373 parameters. Don't try to use its default argument yet,
20374 but do check whether the arguments we already have cause
20375 substitution failure, so that that happens before we try
20376 later default arguments (78489). */
20378 NULL_TREE);
20381 else
20383 }
20384 else
20385 {
20393 else
20395 }
20406 {
20408 /* The position of the first default template argument,
20409 is also the number of non-defaulted arguments in TARGS.
20410 Record that. */
20413 }
20414 }
20418 }
20424 }
20426 /* Subroutine of type_unification_real. Args are like the variables
20427 at the call site. ARG is an overloaded function (or template-id);
20428 we try deducing template args from each of the overloads, and if
20429 only one succeeds, we go with that. Modifies TARGS and returns
20430 true on success. */
20432 static bool
20434 tree targs,
20435 tree parm,
20436 tree arg,
20437 unification_kind_t strict,
20440 {
20447 {
20450 }
20451 else
20455 /* Handle `&x' where `x' is some static or non-static member
20456 function name. */
20462 /* Strip baselink information. */
20467 {
20468 /* If we got some explicit template args, we need to plug them into
20469 the affected templates before we try to unify, in case the
20470 explicit args will completely resolve the templates in question. */
20477 {
20490 {
20495 {
20498 }
20499 }
20502 }
20503 /* If no templates (or more than one) are fully resolved by the
20504 explicit arguments, this template-id is a non-deduced context; it
20505 could still be OK if we deduce all template arguments for the
20506 enclosing call through other arguments. */
20509 }
20512 /* If ARG is, for example, "(0, &f)" then its type will be unknown
20513 -- but the deduction does not succeed because the expression is
20514 not just the function on its own. */
20516 else
20518 {
20523 {
20526 }
20527 }
20529 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20530 to function or pointer to member function argument if the set of
20531 overloaded functions does not contain function templates and at most
20532 one of a set of overloaded functions provides a unique match.
20534 So if we found multiple possibilities, we return success but don't
20535 deduce anything. */
20538 {
20542 {
20547 /* Don't forget explicit template arguments in a pack. */
20551 }
20552 }
20557 }
20559 /* Core DR 115: In contexts where deduction is done and fails, or in
20560 contexts where deduction is not done, if a template argument list is
20561 specified and it, along with any default template arguments, identifies
20562 a single function template specialization, then the template-id is an
20563 lvalue for the function template specialization. */
20565 tree
20567 {
20580 {
20583 }
20585 {
20588 }
20590 {
20593 }
20596 {
20600 /* If we got some explicit template args, we need to plug them into
20601 the affected templates before we try to unify, in case the
20602 explicit args will completely resolve the templates in question. */
20610 {
20623 {
20626 {
20629 }
20631 {
20634 }
20635 }
20636 }
20638 {
20646 {
20647 tree base
20650 }
20654 }
20656 /* There were no good options and at least one bad one, so let the
20657 user know what the problem is. */
20659 }
20661 }
20663 /* Subroutine of resolve_overloaded_unification; does deduction for a single
20664 overload. Fills TARGS with any deduced arguments, or error_mark_node if
20665 different overloads deduce different arguments for a given parm.
20666 ADDR_P is true if the expression for which deduction is being
20667 performed was of the form "& fn" rather than simply "fn".
20669 Returns 1 on success. */
20671 static int
20673 tree orig_targs,
20674 tree targs,
20675 tree parm,
20676 tree arg,
20677 unification_kind_t strict,
20681 {
20683 tree tempargs;
20689 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20690 to function or pointer to member function argument if the set of
20691 overloaded functions does not contain function templates and at most
20692 one of a set of overloaded functions provides a unique match.
20694 So if this is a template, just return success. */
20706 /* We don't copy orig_targs for this because if we have already deduced
20707 some template args from previous args, unify would complain when we
20708 try to deduce a template parameter for the same argument, even though
20709 there isn't really a conflict. */
20716 /* First make sure we didn't deduce anything that conflicts with
20717 explicitly specified args. */
20719 {
20726 /* Since we're unifying against ourselves, we will fill in
20727 template args used in the function parm list with our own
20728 template parms. Discard them. */
20731 {
20732 /* Check that the argument at each index of the deduced argument pack
20733 is equivalent to the corresponding explicitly specified argument.
20734 We may have deduced more arguments than were explicitly specified,
20735 and that's OK. */
20737 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
20738 that's wrong if we deduce the same argument pack from multiple
20739 function arguments: it's only incomplete the first time. */
20752 }
20755 }
20758 {
20763 }
20766 }
20768 /* PARM is a template class (perhaps with unbound template
20769 parameters). ARG is a fully instantiated type. If ARG can be
20770 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
20771 TARGS are as for unify. */
20773 static tree
20776 {
20777 tree copy_of_targs;
20787 /* We need to make a new template argument vector for the call to
20788 unify. If we used TARGS, we'd clutter it up with the result of
20789 the attempted unification, even if this class didn't work out.
20790 We also don't want to commit ourselves to all the unifications
20791 we've already done, since unification is supposed to be done on
20792 an argument-by-argument basis. In other words, consider the
20793 following pathological case:
20795 template <int I, int J, int K>
20796 struct S {};
20798 template <int I, int J>
20799 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
20801 template <int I, int J, int K>
20802 void f(S<I, J, K>, S<I, I, I>);
20804 void g() {
20805 S<0, 0, 0> s0;
20806 S<0, 1, 2> s2;
20808 f(s0, s2);
20809 }
20811 Now, by the time we consider the unification involving `s2', we
20812 already know that we must have `f<0, 0, 0>'. But, even though
20813 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
20814 because there are two ways to unify base classes of S<0, 1, 2>
20815 with S<I, I, I>. If we kept the already deduced knowledge, we
20816 would reject the possibility I=1. */
20820 {
20824 }
20826 /* If unification failed, we're done. */
20832 }
20834 /* Given a template type PARM and a class type ARG, find the unique
20835 base type in ARG that is an instance of PARM. We do not examine
20836 ARG itself; only its base-classes. If there is not exactly one
20837 appropriate base class, return NULL_TREE. PARM may be the type of
20838 a partial specialization, as well as a plain template type. Used
20839 by unify. */
20841 static enum template_base_result
20844 {
20846 tree binfo;
20852 {
20853 /* The type could not be completed. */
20856 }
20858 /* Walk in inheritance graph order. The search order is not
20859 important, and this avoids multiple walks of virtual bases. */
20861 {
20866 {
20867 /* If there is more than one satisfactory baseclass, then:
20869 [temp.deduct.call]
20871 If they yield more than one possible deduced A, the type
20872 deduction fails.
20874 applies. */
20876 {
20879 }
20882 }
20883 }
20887 }
20889 /* Returns the level of DECL, which declares a template parameter. */
20891 static int
20893 {
20895 {
20905 }
20907 }
20909 /* Decide whether ARG can be unified with PARM, considering only the
20910 cv-qualifiers of each type, given STRICT as documented for unify.
20911 Returns nonzero iff the unification is OK on that basis. */
20913 static int
20915 {
20921 {
20922 /* Although a CVR qualifier is ignored when being applied to a
20923 substituted template parameter ([8.3.2]/1 for example), that
20924 does not allow us to unify "const T" with "int&" because both
20925 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
20926 It is ok when we're allowing additional CV qualifiers
20927 at the outer level [14.8.2.1]/3,1st bullet. */
20937 }
20948 }
20950 /* Determines the LEVEL and INDEX for the template parameter PARM. */
20951 void
20953 {
20957 {
20960 }
20961 else
20962 {
20965 }
20966 }
20968 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
20969 do { \
20970 if (unify (TP, TA, P, A, S, EP)) \
20971 return 1; \
20972 } while (0)
20974 /* Unifies the remaining arguments in PACKED_ARGS with the pack
20975 expansion at the end of PACKED_PARMS. Returns 0 if the type
20976 deduction succeeds, 1 otherwise. STRICT is the same as in
20977 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
20978 function call argument list. We'll need to adjust the arguments to make them
20979 types. SUBR tells us if this is from a recursive call to
20980 type_unification_real, or for comparing two template argument
20981 lists. */
20983 static int
20987 {
20988 tree parm
20994 /* Add in any args remembered from an earlier partial instantiation. */
21002 /* Determine the parameter packs we will be deducing from the
21003 pattern, and record their current deductions. */
21006 {
21010 /* Only template parameter packs can be deduced, not e.g. function
21011 parameter packs or __bases or __integer_pack. */
21015 /* Determine the index and level of this parameter pack. */
21020 /* Keep track of the parameter packs and their corresponding
21021 argument packs. */
21024 }
21026 /* Loop through all of the arguments that have not yet been
21027 unified and unify each with the pattern. */
21029 {
21030 tree parm;
21034 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
21035 or the element of its argument pack at the current index if
21036 this argument was explicitly specified. */
21038 {
21047 {
21050 }
21052 }
21054 /* If we had explicit template arguments, substitute them into the
21055 pattern before deduction. */
21057 {
21058 /* Some arguments might still be unspecified or dependent. */
21066 NULL_TREE);
21071 }
21072 else
21075 /* Unify the pattern with the current argument. */
21077 explain_p))
21080 /* For each parameter pack, collect the deduced value. */
21082 {
21088 }
21089 }
21091 /* Verify that the results of unification with the parameter packs
21092 produce results consistent with what we've seen before, and make
21093 the deduced argument packs available. */
21095 {
21102 /* By default keep the original deduced argument pack.
21103 If necessary, more specific code is going to update the
21104 resulting deduced argument later down in this function. */
21108 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
21109 actually deduce anything. */
21117 {
21118 /* If we had fewer function args than explicit template args,
21119 just use the explicits. */
21124 }
21127 {
21128 tree result;
21129 /* Build the deduced *_ARGUMENT_PACK. */
21131 {
21134 }
21135 else
21140 /* Note the deduced argument packs for this parameter
21141 pack. */
21143 }
21147 {
21148 /* We only had the explicitly-provided arguments before, but
21149 now we have a complete set of arguments. */
21155 }
21156 else
21157 {
21163 /* Inconsistent unification of this parameter pack. */
21165 bad_old_arg,
21166 bad_new_arg);
21167 }
21168 }
21171 }
21173 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
21174 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
21175 parameters and return value are as for unify. */
21177 static int
21181 {
21182 tree parm_max;
21183 tree arg_max;
21187 /* Our representation of array types uses "N - 1" as the
21188 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
21189 not an integer constant. We cannot unify arbitrarily
21190 complex expressions, so we eliminate the MINUS_EXPRs
21191 here. */
21195 {
21198 }
21202 {
21203 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
21204 trying to unify the type of a variable with the type
21205 of a template parameter. For example:
21207 template <unsigned int N>
21208 void f (char (&) [N]);
21209 int g();
21210 void h(int i) {
21211 char a[g(i)];
21212 f(a);
21213 }
21215 Here, the type of the ARG will be "int [g(i)]", and
21216 may be a SAVE_EXPR, etc. */
21220 }
21222 /* If only one of the bounds used a MINUS_EXPR, compensate
21223 by adding one to the other bound. */
21226 integer_type_node,
21227 parm_max,
21228 integer_one_node);
21231 integer_type_node,
21232 arg_max,
21233 integer_one_node);
21237 }
21239 /* Returns whether T, a P or A in unify, is a type, template or expression. */
21243 static pa_kind_t
21245 {
21254 else
21256 }
21258 /* Deduce the value of template parameters. TPARMS is the (innermost)
21259 set of template parameters to a template. TARGS is the bindings
21260 for those template parameters, as determined thus far; TARGS may
21261 include template arguments for outer levels of template parameters
21262 as well. PARM is a parameter to a template function, or a
21263 subcomponent of that parameter; ARG is the corresponding argument.
21264 This function attempts to match PARM with ARG in a manner
21265 consistent with the existing assignments in TARGS. If more values
21266 are deduced, then TARGS is updated.
21268 Returns 0 if the type deduction succeeds, 1 otherwise. The
21269 parameter STRICT is a bitwise or of the following flags:
21271 UNIFY_ALLOW_NONE:
21272 Require an exact match between PARM and ARG.
21273 UNIFY_ALLOW_MORE_CV_QUAL:
21274 Allow the deduced ARG to be more cv-qualified (by qualification
21275 conversion) than ARG.
21276 UNIFY_ALLOW_LESS_CV_QUAL:
21277 Allow the deduced ARG to be less cv-qualified than ARG.
21278 UNIFY_ALLOW_DERIVED:
21279 Allow the deduced ARG to be a template base class of ARG,
21280 or a pointer to a template base class of the type pointed to by
21281 ARG.
21282 UNIFY_ALLOW_INTEGER:
21283 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
21284 case for more information.
21285 UNIFY_ALLOW_OUTER_LEVEL:
21286 This is the outermost level of a deduction. Used to determine validity
21287 of qualification conversions. A valid qualification conversion must
21288 have const qualified pointers leading up to the inner type which
21289 requires additional CV quals, except at the outer level, where const
21290 is not required [conv.qual]. It would be normal to set this flag in
21291 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
21292 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
21293 This is the outermost level of a deduction, and PARM can be more CV
21294 qualified at this point.
21295 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
21296 This is the outermost level of a deduction, and PARM can be less CV
21297 qualified at this point. */
21299 static int
21302 {
21304 tree targ;
21305 tree tparm;
21307 tsubst_flags_t complain = (explain_p
21308 ? tf_warning_or_error
21311 /* I don't think this will do the right thing with respect to types.
21312 But the only case I've seen it in so far has been array bounds, where
21313 signedness is the only information lost, and I think that will be
21314 okay. */
21322 /* We can't deduce anything from this, but we might get all the
21323 template args from other function args. */
21329 /* If PARM uses template parameters, then we can't bail out here,
21330 even if ARG == PARM, since we won't record unifications for the
21331 template parameters. We might need them if we're trying to
21332 figure out which of two things is more specialized. */
21336 /* Handle init lists early, so the rest of the function can assume
21337 we're dealing with a type. */
21339 {
21344 /* Replace T with std::initializer_list<T> for deduction. */
21351 /* We can only deduce from an initializer list argument if the
21352 parameter is std::initializer_list or an array; otherwise this
21353 is a non-deduced context. */
21358 else
21359 {
21361 /* Deduction is defined in terms of a single type, so just punt
21362 on the (bizarre) std::initializer_list<T...>. */
21365 }
21368 {
21375 {
21379 /* It should only be possible to get here for a call. */
21381 elt_strict |= maybe_adjust_types_for_deduction
21384 }
21387 explain_p);
21388 }
21392 {
21393 /* Also deduce from the length of the initializer list. */
21400 }
21402 /* If the std::initializer_list<T> deduction worked, replace the
21403 deduced A with std::initializer_list<A>. */
21405 {
21410 }
21412 }
21414 /* If parm and arg aren't the same kind of thing (template, type, or
21415 expression), fail early. */
21419 /* Immediately reject some pairs that won't unify because of
21420 cv-qualification mismatches. */
21423 /* It is the elements of the array which hold the cv quals of an array
21424 type, and the elements might be template type parms. We'll check
21425 when we recurse. */
21427 /* We check the cv-qualifiers when unifying with template type
21428 parameters below. We want to allow ARG `const T' to unify with
21429 PARM `T' for example, when computing which of two templates
21430 is more specialized, for example. */
21444 {
21448 /* In a type which contains a nested-name-specifier, template
21449 argument values cannot be deduced for template parameters used
21450 within the nested-name-specifier. */
21462 /* The PARM is not one we're trying to unify. Just check
21463 to see if it matches ARG. */
21464 {
21469 else
21471 }
21478 /* Check for mixed types and values. */
21486 {
21489 {
21490 /* First try to match ARG directly. */
21492 explain_p);
21494 {
21495 /* Otherwise, look for a suitable base of ARG, as below. */
21502 }
21503 }
21504 /* ARG must be constructed from a template class or a template
21505 template parameter. */
21510 /* Deduce arguments T, i from TT<T> or TT<i>. */
21516 /* Fall through to deduce template name. */
21517 }
21521 {
21522 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
21524 /* Simple cases: Value already set, does match or doesn't. */
21529 }
21530 else
21531 {
21532 /* If PARM is `const T' and ARG is only `int', we don't have
21533 a match unless we are allowing additional qualification.
21534 If ARG is `const int' and PARM is just `T' that's OK;
21535 that binds `const int' to `T'. */
21540 /* Consider the case where ARG is `const volatile int' and
21541 PARM is `const T'. Then, T should be `volatile int'. */
21542 arg = cp_build_qualified_type_real
21547 /* Simple cases: Value already set, does match or doesn't. */
21553 /* Make sure that ARG is not a variable-sized array. (Note
21554 that were talking about variable-sized arrays (like
21555 `int[n]'), rather than arrays of unknown size (like
21556 `int[]').) We'll get very confused by such a type since
21557 the bound of the array is not constant, and therefore
21558 not mangleable. Besides, such types are not allowed in
21559 ISO C++, so we can do as we please here. We do allow
21560 them for 'auto' deduction, since that isn't ABI-exposed. */
21564 /* Strip typedefs as in convert_template_argument. */
21566 }
21568 /* If ARG is a parameter pack or an expansion, we cannot unify
21569 against it unless PARM is also a parameter pack. */
21574 /* If the argument deduction results is a METHOD_TYPE,
21575 then there is a problem.
21576 METHOD_TYPE doesn't map to any real C++ type the result of
21577 the deduction can not be of that type. */
21591 {
21592 /* The PARM is not one we're trying to unify. Just check
21593 to see if it matches ARG. */
21599 }
21605 {
21609 /* We're deducing from an array bound, the type doesn't matter. */
21615 }
21617 /* [temp.deduct.type] If, in the declaration of a function template
21618 with a non-type template-parameter, the non-type
21619 template-parameter is used in an expression in the function
21620 parameter-list and, if the corresponding template-argument is
21621 deduced, the template-argument type shall match the type of the
21622 template-parameter exactly, except that a template-argument
21623 deduced from an array bound may be of any integral type.
21624 The non-type parameter might use already deduced type parameters. */
21627 /* We don't have enough levels of args to do any substitution. This
21629 else
21630 {
21636 {
21640 }
21641 }
21644 /* Template-parameter dependent expression. Just accept it for now.
21645 It will later be processed in convert_template_argument. */
21646 ;
21652 /* Convert the ARG to the type of PARM; the deduced non-type
21653 template argument must exactly match the types of the
21654 corresponding parameter. */
21657 {
21658 /* We haven't deduced the type of this parameter yet. */
21660 /* We deduce from array bounds in try_array_deduction. */
21662 {
21663 /* Deduce it from the non-type argument. */
21668 }
21669 else
21670 /* Try again later. */
21672 }
21673 else
21676 /* If ARG is a parameter pack or an expansion, we cannot unify
21677 against it unless PARM is also a parameter pack. */
21682 {
21685 }
21690 {
21691 /* A pointer-to-member constant can be unified only with
21692 another constant. */
21696 /* Just unify the class member. It would be useless (and possibly
21697 wrong, depending on the strict flags) to unify also
21698 PTRMEM_CST_CLASS, because we want to be sure that both parm and
21699 arg refer to the same variable, even if through different
21700 classes. For instance:
21702 struct A { int x; };
21703 struct B : A { };
21705 Unification of &A::x and &B::x must succeed. */
21708 }
21711 {
21715 /* [temp.deduct.call]
21717 A can be another pointer or pointer to member type that can
21718 be converted to the deduced A via a qualification
21719 conversion (_conv.qual_).
21721 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
21722 This will allow for additional cv-qualification of the
21723 pointed-to types if appropriate. */
21726 /* The derived-to-base conversion only persists through one
21727 level of pointers. */
21732 }
21764 /* We have already checked cv-qualification at the top of the
21765 function. */
21769 /* As far as unification is concerned, this wins. Later checks
21770 will invalidate it if necessary. */
21773 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
21774 /* Type INTEGER_CST can come from ordinary constant template args. */
21786 {
21796 /* Check for pack expansions in the parameters. */
21798 {
21800 {
21802 /* We can unify against something with a trailing
21803 parameter pack. */
21805 else
21806 /* [temp.deduct.type]/9: If the template argument list of
21807 P contains a pack expansion that is not the last
21808 template argument, the entire template argument list
21809 is a non-deduced context. */
21811 }
21812 }
21814 /* If we don't have enough arguments to satisfy the parameters
21815 (not counting the pack expression at the end), or we have
21816 too many arguments for a parameter list that doesn't end in
21817 a pack expression, we can't unify. */
21823 /* Unify all of the parameters that precede the (optional)
21824 pack expression. */
21826 {
21831 }
21834 DEDUCE_EXACT,
21837 }
21845 {
21853 }
21858 {
21862 {
21863 /* First, we try to unify the PARM and ARG directly. */
21868 {
21869 /* Fallback to the special case allowed in
21870 [temp.deduct.call]:
21872 If P is a class, and P has the form
21873 template-id, then A can be a derived class of
21874 the deduced A. Likewise, if P is a pointer to
21875 a class of the form template-id, A can be a
21876 pointer to a derived class pointed to by the
21877 deduced A. */
21883 {
21884 /* Don't give the derived diagnostic if we're
21885 already dealing with the same template. */
21886 bool same_template
21892 }
21893 }
21894 }
21898 /* Perhaps PARM is something like S<U> and ARG is S<int>.
21899 Then, we should unify `int' and `U'. */
21901 else
21902 /* There's no chance of unification succeeding. */
21907 }
21914 {
21917 tree a;
21923 /* CV qualifications for methods can never be deduced, they must
21924 match exactly. We need to check them explicitly here,
21925 because type_unification_real treats them as any other
21926 cv-qualified parameter. */
21928 && (!check_cv_quals_for_unify
21956 {
21968 }
21971 }
21974 /* Unify a pointer to member with a pointer to member function, which
21975 deduces the type of the member as a function type. */
21977 {
21978 /* Check top-level cv qualifiers */
21986 /* Determine the type of the function we are unifying against. */
21990 }
22009 /* Matched cases are handled by the ARG == PARM test above. */
22013 /* We might get a variable as a non-type template argument in parm if the
22014 corresponding parameter is type-dependent. Make any necessary
22015 adjustments based on whether arg is a reference. */
22019 {
22024 }
22025 /* Now use the normal expression code to check whether they match. */
22036 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
22037 or UNDERLYING_TYPE nodes. */
22041 /* Unification fails if we hit an error node. */
22046 {
22056 }
22057 /* FALLTHRU */
22060 /* An unresolved overload is a nondeduced context. */
22064 expr:
22065 /* We must be looking at an expression. This can happen with
22066 something like:
22068 template <int I>
22069 void foo(S<I>, S<I + 2>);
22071 This is a "nondeduced context":
22073 [deduct.type]
22075 The nondeduced contexts are:
22077 --A type that is a template-id in which one or more of
22078 the template-arguments is an expression that references
22079 a template-parameter.
22081 In these cases, we assume deduction succeeded, but don't
22082 actually infer any unifications. */
22087 else
22089 }
22090 }
22091 #undef RECUR_AND_CHECK_FAILURE
22092 \f
22093 /* Note that DECL can be defined in this translation unit, if
22094 required. */
22096 static void
22098 {
22099 tree clone;
22103 }
22105 /* Called if RESULT is explicitly instantiated, or is a member of an
22106 explicitly instantiated class. */
22108 void
22110 {
22113 /* If this entity has already been written out, it's too late to
22114 make any modifications. */
22118 /* For anonymous namespace we don't need to do anything. */
22120 {
22123 }
22126 /* The TREE_PUBLIC flag for function declarations will have been
22127 set correctly by tsubst. */
22130 /* This might have been set by an earlier implicit instantiation. */
22135 else
22136 {
22139 /* Always make artificials weak. */
22142 /* For WIN32 we also want to put explicit instantiations in
22143 linkonce sections. */
22146 }
22148 /* If EXTERN_P, then this function will not be emitted -- unless
22149 followed by an explicit instantiation, at which point its linkage
22150 will be adjusted. If !EXTERN_P, then this function will be
22151 emitted here. In neither circumstance do we want
22152 import_export_decl to adjust the linkage. */
22154 }
22156 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
22157 important template arguments. If any are missing, we check whether
22158 they're important by using error_mark_node for substituting into any
22159 args that were used for partial ordering (the ones between ARGS and END)
22160 and seeing if it bubbles up. */
22162 static bool
22164 {
22169 {
22172 }
22174 {
22178 }
22180 }
22182 /* Given two function templates PAT1 and PAT2, return:
22184 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
22185 -1 if PAT2 is more specialized than PAT1.
22186 0 if neither is more specialized.
22188 LEN indicates the number of parameters we should consider
22189 (defaulted parameters should not be considered).
22191 The 1998 std underspecified function template partial ordering, and
22192 DR214 addresses the issue. We take pairs of arguments, one from
22193 each of the templates, and deduce them against each other. One of
22194 the templates will be more specialized if all the *other*
22195 template's arguments deduce against its arguments and at least one
22196 of its arguments *does* *not* deduce against the other template's
22197 corresponding argument. Deduction is done as for class templates.
22198 The arguments used in deduction have reference and top level cv
22199 qualifiers removed. Iff both arguments were originally reference
22200 types *and* deduction succeeds in both directions, an lvalue reference
22201 wins against an rvalue reference and otherwise the template
22202 with the more cv-qualified argument wins for that pairing (if
22203 neither is more cv-qualified, they both are equal). Unlike regular
22204 deduction, after all the arguments have been deduced in this way,
22205 we do *not* verify the deduced template argument values can be
22206 substituted into non-deduced contexts.
22208 The logic can be a bit confusing here, because we look at deduce1 and
22209 targs1 to see if pat2 is at least as specialized, and vice versa; if we
22210 can find template arguments for pat1 to make arg1 look like arg2, that
22211 means that arg2 is at least as specialized as arg1. */
22213 int
22215 {
22228 /* Remove the this parameter from non-static member functions. If
22229 one is a non-static member function and the other is not a static
22230 member function, remove the first parameter from that function
22231 also. This situation occurs for operator functions where we
22232 locate both a member function (with this pointer) and non-member
22233 operator (with explicit first operand). */
22235 {
22240 }
22242 {
22245 {
22246 len--;
22248 }
22249 }
22251 /* If only one is a conversion operator, they are unordered. */
22255 /* Consider the return type for a conversion function */
22257 {
22260 len++;
22261 }
22263 processing_template_decl++;
22269 /* Stop when an ellipsis is seen. */
22271 {
22282 {
22283 /* When both arguments are pack expansions, we need only
22284 unify the patterns themselves. */
22288 /* This is the last comparison we need to do. */
22290 }
22292 /* DR 1847: If a particular P contains no template-parameters that
22293 participate in template argument deduction, that P is not used to
22294 determine the ordering. */
22300 {
22304 }
22307 {
22311 }
22317 {
22323 /* Setup the parameter vector, which contains only ARG1. */
22326 /* Setup the argument vector, which contains the remaining
22327 arguments. */
22336 /* We cannot deduce in the other direction, because ARG1 is
22337 a pack expansion but ARG2 is not. */
22339 }
22341 {
22347 /* Setup the parameter vector, which contains only ARG1. */
22350 /* Setup the argument vector, which contains the remaining
22351 arguments. */
22360 /* We cannot deduce in the other direction, because ARG2 is
22361 a pack expansion but ARG1 is not.*/
22363 }
22365 else
22366 {
22367 /* The normal case, where neither argument is a pack
22368 expansion. */
22375 }
22377 /* If we couldn't deduce arguments for tparms1 to make arg1 match
22378 arg2, then arg2 is not as specialized as arg1. */
22384 /* "If, for a given type, deduction succeeds in both directions
22385 (i.e., the types are identical after the transformations above)
22386 and both P and A were reference types (before being replaced with
22387 the type referred to above):
22388 - if the type from the argument template was an lvalue reference and
22389 the type from the parameter template was not, the argument type is
22390 considered to be more specialized than the other; otherwise,
22391 - if the type from the argument template is more cv-qualified
22392 than the type from the parameter template (as described above),
22393 the argument type is considered to be more specialized than the other;
22394 otherwise,
22395 - neither type is more specialized than the other." */
22398 {
22400 {
22403 else
22405 }
22407 {
22412 }
22413 }
22416 /* We've failed to deduce something in either direction.
22417 These must be unordered. */
22420 next:
22424 /* We have already processed all of the arguments in our
22425 handing of the pack expansion type. */
22430 }
22432 /* "In most cases, all template parameters must have values in order for
22433 deduction to succeed, but for partial ordering purposes a template
22434 parameter may remain without a value provided it is not used in the
22435 types being used for partial ordering."
22437 Thus, if we are missing any of the targs1 we need to substitute into
22438 origs1, then pat2 is not as specialized as pat1. This can happen when
22439 there is a nondeduced context. */
22445 processing_template_decl--;
22447 /* If both deductions succeed, the partial ordering selects the more
22448 constrained template. */
22450 {
22455 }
22457 /* All things being equal, if the next argument is a pack expansion
22458 for one function but not for the other, prefer the
22459 non-variadic function. FIXME this is bogus; see c++/41958. */
22463 {
22466 }
22472 else
22474 }
22476 /* Determine which of two partial specializations of TMPL is more
22477 specialized.
22479 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
22480 to the first partial specialization. The TREE_PURPOSE is the
22481 innermost set of template parameters for the partial
22482 specialization. PAT2 is similar, but for the second template.
22484 Return 1 if the first partial specialization is more specialized;
22485 -1 if the second is more specialized; 0 if neither is more
22486 specialized.
22488 See [temp.class.order] for information about determining which of
22489 two templates is more specialized. */
22491 static int
22493 {
22494 tree targs;
22503 /* Just like what happens for functions, if we are ordering between
22504 different template specializations, we may encounter dependent
22505 types in the arguments, and we need our dependency check functions
22506 to behave correctly. */
22510 {
22513 }
22517 {
22520 }
22523 /* If both deductions succeed, the partial ordering selects the more
22524 constrained template. */
22528 /* In the case of a tie where at least one of the templates
22529 has a parameter pack at the end, the template with the most
22530 non-packed parameters wins. */
22532 && any_deductions
22535 {
22541 /* We don't count the pack expansion at the end. */
22551 }
22554 }
22556 /* Return the template arguments that will produce the function signature
22557 DECL from the function template FN, with the explicit template
22558 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
22559 also match. Return NULL_TREE if no satisfactory arguments could be
22560 found. */
22562 static tree
22564 {
22568 tree decl_arg_types;
22571 tree arg;
22575 /* Never do unification on the 'this' parameter. */
22596 }
22598 /* Return the innermost template arguments that, when applied to a partial
22599 specialization SPEC_TMPL of TMPL, yield the ARGS.
22601 For example, suppose we have:
22603 template <class T, class U> struct S {};
22604 template <class T> struct S<T*, int> {};
22606 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
22607 partial specialization and the ARGS will be {double*, int}. The resulting
22608 vector will be {double}, indicating that `T' is bound to `double'. */
22610 static tree
22612 {
22614 tree spec_args
22617 tree deduced_args;
22618 tree innermost_deduced_args;
22622 {
22626 innermost_deduced_args);
22627 }
22628 else
22632 again:
22641 {
22643 {
22649 }
22651 }
22654 {
22657 }
22659 /* Verify that nondeduced template arguments agree with the type
22660 obtained from argument deduction.
22662 For example:
22664 struct A { typedef int X; };
22665 template <class T, class U> struct C {};
22666 template <class T> struct C<T, typename T::X> {};
22668 Then with the instantiation `C<A, int>', we can deduce that
22669 `T' is `A' but unify () does not check whether `typename T::X'
22670 is `int'. */
22681 /* We only need to check the innermost arguments; the other
22682 arguments will always agree. */
22687 /* Now that we have bindings for all of the template arguments,
22688 ensure that the arguments deduced for the template template
22689 parameters have compatible template parameter lists. See the use
22690 of template_template_parm_bindings_ok_p in fn_type_unification
22691 for more information. */
22696 }
22698 // Compare two function templates T1 and T2 by deducing bindings
22699 // from one against the other. If both deductions succeed, compare
22700 // constraints to see which is more constrained.
22701 static int
22703 {
22708 {
22711 }
22714 {
22717 }
22719 // If both deductions succeed, then one may be more constrained.
22724 }
22726 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
22727 Return the TREE_LIST node with the most specialized template, if
22728 any. If there is no most specialized template, the error_mark_node
22729 is returned.
22731 Note that this function does not look at, or modify, the
22732 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
22733 returned is one of the elements of INSTANTIATIONS, callers may
22734 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
22735 and retrieve it from the value returned. */
22737 tree
22739 {
22746 {
22752 {
22753 /* Equally specialized, move to next function. If there
22754 is no next function, nothing's most specialized. */
22759 }
22760 }
22763 /* Now verify that champ is better than everything earlier in the
22764 instantiation list. */
22767 {
22770 }
22771 }
22773 processing_template_decl--;
22779 }
22781 /* If DECL is a specialization of some template, return the most
22782 general such template. Otherwise, returns NULL_TREE.
22784 For example, given:
22786 template <class T> struct S { template <class U> void f(U); };
22788 if TMPL is `template <class U> void S<int>::f(U)' this will return
22789 the full template. This function will not trace past partial
22790 specializations, however. For example, given in addition:
22792 template <class T> struct S<T*> { template <class U> void f(U); };
22794 if TMPL is `template <class U> void S<int*>::f(U)' this will return
22795 `template <class T> template <class U> S<T*>::f(U)'. */
22797 tree
22799 {
22801 {
22804 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
22805 template friend, or a FIELD_DECL for a capture pack. */
22808 }
22810 /* Look for more and more general templates. */
22812 {
22813 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
22814 (See cp-tree.h for details.) */
22823 /* Stop if we run into an explicitly specialized class template. */
22830 }
22833 }
22835 /* Return the most specialized of the template partial specializations
22836 which can produce TARGET, a specialization of some class or variable
22837 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
22838 a TEMPLATE_DECL node corresponding to the partial specialization, while
22839 the TREE_PURPOSE is the set of template arguments that must be
22840 substituted into the template pattern in order to generate TARGET.
22842 If the choice of partial specialization is ambiguous, a diagnostic
22843 is issued, and the error_mark_node is returned. If there are no
22844 partial specializations matching TARGET, then NULL_TREE is
22845 returned, indicating that the primary template should be used. */
22847 static tree
22849 {
22851 tree t;
22852 tree champ;
22859 {
22863 }
22865 {
22868 }
22870 {
22874 }
22875 else
22880 /* For determining which partial specialization to use, only the
22881 innermost args are interesting. */
22883 {
22886 }
22889 {
22890 tree spec_args;
22894 {
22895 /* Substitute in the template args from the enclosing class. */
22899 }
22906 {
22910 /* Keep the candidate only if the constraints are satisfied,
22911 or if we're not compiling with concepts. */
22914 {
22917 }
22918 }
22919 }
22929 {
22932 ;
22933 else
22934 {
22936 {
22939 {
22942 }
22943 }
22945 }
22946 }
22950 {
22953 {
22956 }
22957 }
22960 {
22967 else
22971 {
22976 }
22979 }
22982 }
22984 /* Explicitly instantiate DECL. */
22986 void
22988 {
22993 /* An error occurred, for which grokdeclarator has already issued
22994 an appropriate message. */
22997 {
23000 }
23006 {
23007 /* There is an asymmetry here in the way VAR_DECLs and
23008 FUNCTION_DECLs are handled by grokdeclarator. In the case of
23009 the latter, the DECL we get back will be marked as a
23010 template instantiation, and the appropriate
23011 DECL_TEMPLATE_INFO will be set up. This does not happen for
23012 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
23013 should handle VAR_DECLs as it currently handles
23014 FUNCTION_DECLs. */
23016 {
23019 }
23022 {
23025 }
23027 {
23032 }
23033 }
23035 {
23038 }
23039 else
23042 /* Check for various error cases. Note that if the explicit
23043 instantiation is valid the RESULT will currently be marked as an
23044 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
23045 until we get here. */
23048 {
23049 /* DR 259 [temp.spec].
23051 Both an explicit instantiation and a declaration of an explicit
23052 specialization shall not appear in a program unless the explicit
23053 instantiation follows a declaration of the explicit specialization.
23055 For a given set of template parameters, if an explicit
23056 instantiation of a template appears after a declaration of an
23057 explicit specialization for that template, the explicit
23058 instantiation has no effect. */
23060 }
23062 {
23063 /* [temp.spec]
23065 No program shall explicitly instantiate any template more
23066 than once.
23068 We check DECL_NOT_REALLY_EXTERN so as not to complain when
23069 the first instantiation was `extern' and the second is not,
23070 and EXTERN_P for the opposite case. */
23073 /* If an "extern" explicit instantiation follows an ordinary
23074 explicit instantiation, the template is instantiated. */
23077 }
23079 {
23082 }
23084 {
23087 }
23090 ;
23092 {
23095 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
23098 }
23099 else
23107 }
23109 static void
23111 {
23117 {
23120 }
23121 }
23123 /* Called from do_type_instantiation through binding_table_foreach to
23124 do recursive instantiation for the type bound in ENTRY. */
23125 static void
23127 {
23134 }
23136 /* Perform an explicit instantiation of template class T. STORAGE, if
23137 non-null, is the RID for extern, inline or static. COMPLAIN is
23138 nonzero if this is called from the parser, zero if called recursively,
23139 since the standard is unclear (as detailed below). */
23141 void
23143 {
23153 {
23154 tree tmpl =
23158 else
23161 }
23166 {
23169 t);
23171 }
23174 {
23176 {
23178 {
23181 "ISO C++ 1998 forbids the use of %<extern%> on "
23183 }
23184 else
23186 "ISO C++ forbids the use of %qE"
23188 }
23196 else
23197 {
23199 storage);
23201 }
23202 }
23205 {
23206 /* DR 259 [temp.spec].
23208 Both an explicit instantiation and a declaration of an explicit
23209 specialization shall not appear in a program unless the explicit
23210 instantiation follows a declaration of the explicit specialization.
23212 For a given set of template parameters, if an explicit
23213 instantiation of a template appears after a declaration of an
23214 explicit specialization for that template, the explicit
23215 instantiation has no effect. */
23217 }
23219 {
23220 /* [temp.spec]
23222 No program shall explicitly instantiate any template more
23223 than once.
23225 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
23226 instantiation was `extern'. If EXTERN_P then the second is.
23227 These cases are OK. */
23234 /* If we've already instantiated the template, just return now. */
23237 }
23245 /* In contrast to implicit instantiation, where only the
23246 declarations, and not the definitions, of members are
23247 instantiated, we have here:
23249 [temp.explicit]
23251 The explicit instantiation of a class template specialization
23252 implies the instantiation of all of its members not
23253 previously explicitly specialized in the translation unit
23254 containing the explicit instantiation.
23256 Of course, we can't instantiate member template classes, since we
23257 don't have any arguments for them. Note that the standard is
23258 unclear on whether the instantiation of the members are
23259 *explicit* instantiations or not. However, the most natural
23260 interpretation is that it should be an explicit
23261 instantiation. */
23265 && !static_p
23268 {
23273 }
23278 }
23280 /* Given a function DECL, which is a specialization of TMPL, modify
23281 DECL to be a re-instantiation of TMPL with the same template
23282 arguments. TMPL should be the template into which tsubst'ing
23283 should occur for DECL, not the most general template.
23285 One reason for doing this is a scenario like this:
23287 template <class T>
23288 void f(const T&, int i);
23290 void g() { f(3, 7); }
23292 template <class T>
23293 void f(const T& t, const int i) { }
23295 Note that when the template is first instantiated, with
23296 instantiate_template, the resulting DECL will have no name for the
23297 first parameter, and the wrong type for the second. So, when we go
23298 to instantiate the DECL, we regenerate it. */
23300 static void
23302 {
23303 /* The arguments used to instantiate DECL, from the most general
23304 template. */
23305 tree code_pattern;
23309 /* Make sure that we can see identifiers, and compute access
23310 correctly. */
23314 {
23315 tree decl_parm;
23316 tree pattern_parm;
23317 tree specs;
23331 specs);
23333 /* Merge parameter declarations. */
23336 pattern_parm
23340 {
23341 tree parm_type;
23342 tree attributes;
23347 NULL_TREE);
23353 {
23356 }
23359 }
23360 /* Merge any parameters that match with the function parameter
23361 pack. */
23363 {
23365 tree expanded_types;
23366 /* Expand the TYPE_PACK_EXPANSION that provides the types for
23367 the parameters in this function parameter pack. */
23372 {
23373 tree parm_type;
23374 tree attributes;
23377 /* Rename the parameter to include the index. */
23386 {
23389 }
23391 }
23392 }
23393 /* Merge additional specifiers from the CODE_PATTERN. */
23397 }
23399 {
23409 }
23410 else
23414 }
23416 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
23417 substituted to get DECL. */
23419 tree
23421 {
23424 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
23425 for the instantiation. This is not always the most general
23426 template. Consider, for example:
23428 template <class T>
23429 struct S { template <class U> void f();
23430 template <> void f<int>(); };
23432 and an instantiation of S<double>::f<int>. We want TD to be the
23433 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
23435 more general template. */
23437 /* We must also deal with friend templates. Given:
23439 template <class T> struct S {
23440 template <class U> friend void f() {};
23441 };
23443 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
23444 so far as the language is concerned, but that's still
23445 where we get the pattern for the instantiation from. On
23446 other hand, if the definition comes outside the class, say:
23448 template <class T> struct S {
23449 template <class U> friend void f();
23450 };
23451 template <class U> friend void f() {}
23453 we don't need to look any further. That's what the check for
23454 DECL_INITIAL is for. */
23458 {
23459 /* The present template, TD, should not be a definition. If it
23460 were a definition, we should be using it! Note that we
23461 cannot restructure the loop to just keep going until we find
23462 a template with a definition, since that might go too far if
23463 a specialization was declared, but not defined. */
23465 /* Fetch the more general template. */
23467 }
23470 }
23472 /* Returns true if we need to instantiate this template instance even if we
23473 know we aren't going to emit it. */
23475 bool
23477 {
23478 /* We always instantiate inline functions so that we can inline them. An
23479 explicit instantiation declaration prohibits implicit instantiation of
23480 non-inline functions. With high levels of optimization, we would
23481 normally inline non-inline functions -- but we're not allowed to do
23482 that for "extern template" functions. Therefore, we check
23483 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
23487 /* And we need to instantiate static data members so that
23488 their initializers are available in integral constant
23489 expressions. */
23492 }
23494 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
23495 instantiate it now, modifying TREE_TYPE (fn). Returns false on
23496 error, true otherwise. */
23498 bool
23500 {
23503 /* Don't instantiate a noexcept-specification from template context. */
23519 {
23525 {
23526 /* If hash_set::add returns true, the element was already there. */
23531 fn);
23533 }
23535 {
23550 }
23551 else
23561 }
23564 {
23567 else
23569 }
23572 }
23574 /* We're starting to process the function INST, an instantiation of PATTERN;
23575 add their parameters to local_specializations. */
23577 static void
23579 {
23583 {
23587 }
23589 {
23591 {
23594 }
23595 else
23596 {
23597 /* Register the (value) argument pack as a specialization of
23598 TMPL_PARM, then move on. */
23601 }
23602 }
23604 }
23606 /* Produce the definition of D, a _DECL generated from a template. If
23607 DEFER_OK is true, then we don't have to actually do the
23608 instantiation now; we just have to do it sometime. Normally it is
23609 an error if this is an explicit instantiation but D is undefined.
23610 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
23611 instantiated class template. */
23613 tree
23615 {
23617 tree gen_args;
23618 tree args;
23619 tree td;
23620 tree code_pattern;
23621 tree spec;
23622 tree gen_tmpl;
23630 /* This function should only be used to instantiate templates for
23631 functions and static member variables. */
23634 /* A concept is never instantiated. */
23637 /* Variables are never deferred; if instantiation is required, they
23638 are instantiated right away. That allows for better code in the
23639 case that an expression refers to the value of the variable --
23640 if the variable has a constant value the referring expression can
23641 take advantage of that fact. */
23645 /* Don't instantiate cloned functions. Instead, instantiate the
23646 functions they cloned. */
23654 /* D has already been instantiated or explicitly specialized, so
23655 there's nothing for us to do here.
23657 It might seem reasonable to check whether or not D is an explicit
23658 instantiation, and, if so, stop here. But when an explicit
23659 instantiation is deferred until the end of the compilation,
23660 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
23661 the instantiation. */
23664 /* Check to see whether we know that this template will be
23665 instantiated in some other file, as with "extern template"
23666 extension. */
23669 /* In general, we do not instantiate such templates. */
23677 /* We should already have the extra args. */
23680 /* And what's in the hash table should match D. */
23684 /* This needs to happen before any tsubsting. */
23690 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
23691 for the instantiation. */
23696 {
23697 /* Look up an explicit specialization, if any. */
23701 {
23704 }
23705 }
23709 /* We should never be trying to instantiate a member of a class
23710 template or partial specialization. */
23715 /* In the case of a friend template whose definition is provided
23716 outside the class, we may have too many arguments. Drop the
23717 ones we don't need. The same is true for specializations. */
23718 args = get_innermost_template_args
23722 {
23728 }
23729 else
23730 {
23735 else
23737 }
23739 /* We may be in the middle of deferred access check. Disable it now. */
23742 /* Unless an explicit instantiation directive has already determined
23743 the linkage of D, remember that a definition is available for
23744 this entity. */
23754 /* If D is a member of an explicitly instantiated class template,
23755 and no definition is available, treat it like an implicit
23756 instantiation. */
23759 {
23760 /* Leave linkage flags alone on instantiations with anonymous
23761 visibility. */
23763 {
23766 }
23768 }
23770 /* Defer all other templates, unless we have been explicitly
23771 forbidden from doing so. */
23773 template. */
23774 ! pattern_defined
23775 /* If it's OK to postpone instantiation, do so. */
23776 || defer_ok
23777 /* If this is a static data member that will be defined
23778 elsewhere, we don't want to instantiate the entire data
23779 member, but we do want to instantiate the initializer so that
23780 we can substitute that elsewhere. */
23782 /* Handle here a deleted function too, avoid generating
23783 its body (c++/61080). */
23785 {
23786 /* The definition of the static data member is now required so
23787 we must substitute the initializer. */
23791 {
23792 tree ns;
23793 tree init;
23802 args,
23805 /* If instantiating the initializer involved instantiating this
23806 again, don't call cp_finish_decl twice. */
23808 {
23809 /* Make sure the initializer is still constant, in case of
23810 circular dependency (template/instantiate6.C). */
23811 const_init
23815 LOOKUP_ONLYCONVERTING);
23816 }
23820 }
23822 /* We restore the source position here because it's used by
23823 add_pending_template. */
23829 /* [temp.explicit]
23831 The definition of a non-exported function template, a
23832 non-exported member function template, or a non-exported
23833 member function or static data member of a class template
23834 shall be present in every translation unit in which it is
23835 explicitly instantiated. */
23839 /* If we're in unevaluated context, we just wanted to get the
23840 constant value; this isn't an odr use, so don't queue
23841 a full instantiation. */
23844 /* ??? Historically, we have instantiated inline functions, even
23845 when marked as "extern template". */
23849 }
23850 /* Tell the repository that D is available in this translation unit
23851 -- and see if it is supposed to be instantiated here. */
23853 {
23854 /* In a PCH file, despite the fact that the repository hasn't
23855 requested instantiation in the PCH it is still possible that
23856 an instantiation will be required in a file that includes the
23857 PCH. */
23860 /* Instantiate inline functions so that the inliner can do its
23861 job, even though we'll not be emitting a copy of this
23862 function. */
23865 }
23868 tree fn_context;
23871 /* tsubst_lambda_expr resolved any references to enclosing functions. */
23882 else
23883 {
23887 }
23889 /* Mark D as instantiated so that recursive calls to
23890 instantiate_decl do not try to instantiate it again. */
23893 /* Regenerate the declaration in case the template has been modified
23894 by a subsequent redeclaration. */
23897 /* We already set the file and line above. Reset them now in case
23898 they changed as a result of calling regenerate_decl_from_template. */
23902 {
23903 tree init;
23906 /* Clear out DECL_RTL; whatever was there before may not be right
23907 since we've reset the type of the declaration. */
23911 /* The initializer is placed in DECL_INITIAL by
23912 regenerate_decl_from_template so we don't need to
23913 push/pop_access_scope again here. Pull it out so that
23914 cp_finish_decl can process it. */
23919 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
23920 initializer. That function will defer actual emission until
23921 we have a chance to determine linkage. */
23924 /* Enter the scope of D so that access-checking works correctly. */
23937 }
23941 {
23942 /* Set up the list of local specializations. */
23946 /* Set up context. */
23950 else
23953 /* Some typedefs referenced from within the template code need to be
23954 access checked at template instantiation time, i.e now. These
23955 types were added to the template at parsing time. Let's get those
23956 and perform the access checks then. */
23958 args);
23960 /* Create substitution entries for the parameters. */
23963 /* Substitute into the body of the function. */
23967 else
23968 {
23973 /* Set the current input_location to the end of the function
23974 so that finish_function knows where we are. */
23975 input_location
23978 /* Remember if we saw an infinite loop in the template. */
23979 current_function_infinite_loop
23981 }
23983 /* Finish the function. */
23987 else
23988 {
23991 }
23995 }
23997 /* We're not deferring instantiation any more. */
24002 else
24008 out:
24017 }
24019 /* Run through the list of templates that we wish we could
24020 instantiate, and instantiate any we can. RETRIES is the
24021 number of times we retry pending template instantiation. */
24023 void
24025 {
24029 /* Instantiating templates may trigger vtable generation. This in turn
24030 may require further template instantiations. We place a limit here
24031 to avoid infinite loop. */
24033 {
24037 "template instantiation depth exceeds maximum of %d"
24038 " instantiating %q+D, possibly from virtual table generation"
24042 /* Pretend that we defined it. */
24045 }
24047 do
24048 {
24053 {
24058 {
24060 {
24075 }
24078 }
24079 else
24080 {
24083 {
24084 instantiation
24090 }
24094 }
24097 {
24098 /* If INSTANTIATION has been instantiated, then we don't
24099 need to consider it again in the future. */
24104 }
24105 else
24106 {
24109 }
24112 }
24114 }
24118 }
24120 /* Substitute ARGVEC into T, which is a list of initializers for
24121 either base class or a non-static data member. The TREE_PURPOSEs
24122 are DECLs, and the TREE_VALUEs are the initializer values. Used by
24123 instantiate_decl. */
24125 static tree
24127 {
24132 {
24133 tree decl;
24134 tree init;
24140 {
24141 tree expr;
24142 tree arg;
24144 /* Expand the base class expansion type into separate base
24145 classes. */
24147 tf_warning_or_error,
24148 NULL_TREE);
24152 /* We'll be building separate TREE_LISTs of arguments for
24153 each base. */
24159 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
24160 expand each argument in the TREE_VALUE of t. */
24167 /* VOID_TYPE_NODE is used to indicate
24168 value-initialization. */
24169 {
24172 }
24173 else
24174 {
24175 /* Substitute parameter packs into each argument in the
24176 TREE_LIST. */
24179 {
24180 tree expanded_exprs;
24182 /* Expand the argument. */
24184 expanded_exprs
24186 tf_warning_or_error,
24187 NULL_TREE);
24191 /* Prepend each of the expanded expressions to the
24192 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
24194 {
24199 }
24200 }
24203 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
24204 since we built them backwards. */
24206 {
24209 }
24210 }
24211 }
24214 {
24216 {
24220 }
24221 else
24222 {
24223 tree tmp;
24238 /* If we had an initializer but it instantiated to nothing,
24239 value-initialize the object. This will only occur when
24240 the initializer was a pack expansion where the parameter
24241 packs used in that expansion were of length zero. */
24244 }
24248 {
24250 decl);
24252 }
24253 /* Look for a target constructor. */
24257 {
24260 {
24264 }
24266 }
24269 {
24273 }
24274 }
24275 }
24277 }
24279 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
24281 static void
24283 {
24288 else
24290 }
24292 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
24293 is the instantiation (which should have been created with
24294 start_enum) and ARGS are the template arguments to use. */
24296 static void
24298 {
24299 tree e;
24305 {
24306 tree value;
24307 tree decl;
24310 /* Note that in a template enum, the TREE_VALUE is the
24311 CONST_DECL, not the corresponding INTEGER_CST. */
24316 /* Give this enumeration constant the correct access. */
24319 /* Actually build the enumerator itself. Here we're assuming that
24320 enumerators can't have dependent attributes. */
24323 }
24333 }
24335 /* DECL is a FUNCTION_DECL that is a template specialization. Return
24336 its type -- but without substituting the innermost set of template
24337 arguments. So, innermost set of template parameters will appear in
24338 the type. */
24340 tree
24342 {
24343 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
24345 }
24347 /* Return truthvalue if we're processing a template different from
24348 the last one involved in diagnostics. */
24349 bool
24351 {
24353 }
24355 /* Remember current template involved in diagnostics. */
24356 void
24358 {
24360 }
24364 {
24366 }
24368 /* Return TRUE if current_function_decl is being instantiated, false
24369 otherwise. */
24371 bool
24373 {
24377 }
24379 /* [temp.param] Check that template non-type parm TYPE is of an allowable
24380 type. Return false for ok, true for disallowed. Issue error and
24381 inform messages under control of COMPLAIN. */
24383 static bool
24385 {
24403 /* A bound template template parm could later be instantiated to have a valid
24404 nontype parm type via an alias template. */
24410 {
24413 else
24415 type);
24416 }
24418 }
24420 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
24421 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
24423 static bool
24425 {
24426 tree scope;
24428 /* [temp.dep.type]
24430 A type is dependent if it is:
24432 -- a template parameter. Template template parameters are types
24433 for us (since TYPE_P holds true for them) so we handle
24434 them here. */
24438 /* -- a qualified-id with a nested-name-specifier which contains a
24439 class-name that names a dependent type or whose unqualified-id
24440 names a dependent type. */
24444 /* An alias template specialization can be dependent even if the
24445 resulting type is not. */
24449 /* -- a cv-qualified type where the cv-unqualified type is
24450 dependent.
24451 No code is necessary for this bullet; the code below handles
24452 cv-qualified types, and we don't want to strip aliases with
24453 TYPE_MAIN_VARIANT because of DR 1558. */
24454 /* -- a compound type constructed from any dependent type. */
24464 {
24465 tree arg_type;
24470 arg_type;
24475 /* A value-dependent noexcept-specifier makes the type dependent. */
24478 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
24479 affect overload resolution and treating it as dependent breaks
24480 things. */
24485 }
24486 /* -- an array type constructed from any dependent type or whose
24487 size is specified by a constant expression that is
24488 value-dependent.
24490 We checked for type- and value-dependence of the bounds in
24491 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
24493 {
24498 }
24500 /* -- a template-id in which either the template name is a template
24501 parameter ... */
24504 /* ... or any of the template arguments is a dependent type or
24505 an expression that is type-dependent or value-dependent. */
24507 && (any_dependent_template_arguments_p
24511 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
24512 dependent; if the argument of the `typeof' expression is not
24513 type-dependent, then it should already been have resolved. */
24519 /* A template argument pack is dependent if any of its packed
24520 arguments are. */
24522 {
24528 }
24530 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
24531 be template parameters. */
24538 /* The standard does not specifically mention types that are local
24539 to template functions or local classes, but they should be
24540 considered dependent too. For example:
24542 template <int I> void f() {
24543 enum E { a = I };
24544 S<sizeof (E)> s;
24545 }
24547 The size of `E' cannot be known until the value of `I' has been
24548 determined. Therefore, `E' must be considered dependent. */
24552 /* Don't use type_dependent_expression_p here, as it can lead
24553 to infinite recursion trying to determine whether a lambda
24554 nested in a lambda is dependent (c++/47687). */
24558 && (any_dependent_template_arguments_p
24562 /* Other types are non-dependent. */
24564 }
24566 /* Returns TRUE if TYPE is dependent, in the sense of
24567 [temp.dep.type]. Note that a NULL type is considered dependent. */
24569 bool
24571 {
24572 /* If there are no template parameters in scope, then there can't be
24573 any dependent types. */
24575 {
24576 /* If we are not processing a template, then nobody should be
24577 providing us with a dependent type. */
24581 }
24583 /* If the type is NULL, we have not computed a type for the entity
24584 in question; in that case, the type is dependent. */
24588 /* Erroneous types can be considered non-dependent. */
24592 /* Getting here with global_type_node means we improperly called this
24593 function on the TREE_TYPE of an IDENTIFIER_NODE. */
24596 /* If we have not already computed the appropriate value for TYPE,
24597 do so now. */
24599 {
24602 }
24605 }
24607 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
24608 lookup. In other words, a dependent type that is not the current
24609 instantiation. */
24611 bool
24613 {
24616 }
24618 /* T is a SCOPE_REF. Return whether it represents a non-static member of
24619 an unknown base of 'this' (and is therefore instantiation-dependent). */
24621 static bool
24623 {
24640 }
24642 /* T is a SCOPE_REF; return whether we need to consider it
24643 instantiation-dependent so that we can check access at instantiation
24644 time even though we know which member it resolves to. */
24646 static bool
24648 {
24655 else
24657 }
24659 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
24660 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
24661 expression. */
24663 /* Note that this predicate is not appropriate for general expressions;
24664 only constant expressions (that satisfy potential_constant_expression)
24665 can be tested for value dependence. */
24667 bool
24669 {
24673 /* A type-dependent expression is also value-dependent. */
24678 {
24680 /* A dependent member function of the current instantiation. */
24684 /* A dependent member function of the current instantiation. */
24691 /* A name that has not been looked up -- must be dependent. */
24695 /* A non-type template parm. */
24699 /* A non-type template parm. */
24705 /* A constant with literal type and is initialized
24706 with an expression that is value-dependent. */
24708 /* FIXME cp_finish_decl doesn't fold reference initializers. */
24712 {
24716 }
24725 /* These expressions are value-dependent if the type to which
24726 the cast occurs is dependent or the expression being casted
24727 is value-dependent. */
24728 {
24734 /* A functional cast has a list of operands. */
24737 {
24738 /* If there are no operands, it must be an expression such
24739 as "int()". This should not happen for aggregate types
24740 because it would form non-constant expressions. */
24745 }
24751 }
24756 /* FALLTHRU */
24759 /* A `sizeof' expression is value-dependent if the operand is
24760 type-dependent or is a pack expansion. */
24769 /* An 'encode' expression is value-dependent if the operand is
24770 type-dependent. */
24779 /* All instantiation-dependent expressions should also be considered
24780 value-dependent. */
24788 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
24789 is value-dependent. */
24790 {
24799 }
24802 {
24819 }
24830 {
24834 }
24837 /* Treat all requires-expressions as value-dependent so
24838 we don't try to fold them. */
24845 {
24852 {
24854 /* In a call to a constexpr member function, look through the
24855 implicit ADDR_EXPR on the object argument so that it doesn't
24856 cause the call to be considered value-dependent. We also
24857 look through it in potential_constant_expression. */
24864 }
24866 }
24872 {
24874 tree val;
24881 }
24884 /* Treat a GNU statement expression as dependent to avoid crashing
24885 under instantiate_non_dependent_expr; it can't be constant. */
24889 /* A constant expression is value-dependent if any subexpression is
24890 value-dependent. */
24892 {
24899 {
24903 {
24906 /* In some cases, some of the operands may be missing.
24907 (For example, in the case of PREDECREMENT_EXPR, the
24908 amount to increment by may be missing.) That doesn't
24909 make the expression dependent. */
24912 }
24913 }
24917 }
24919 }
24921 /* The expression is not value-dependent. */
24923 }
24925 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
24926 [temp.dep.expr]. Note that an expression with no type is
24927 considered dependent. Other parts of the compiler arrange for an
24928 expression with type-dependent subexpressions to have no type, so
24929 this function doesn't have to be fully recursive. */
24931 bool
24933 {
24942 /* An unresolved name is always dependent. */
24948 /* A fold expression is type-dependent. */
24955 /* Some expression forms are never type-dependent. */
24969 /* The types of these expressions depends only on the type to which
24970 the cast occurs. */
24979 /* The types of these expressions depends only on the type created
24980 by the expression. */
24983 {
24984 /* For NEW_EXPR tree nodes created inside a template, either
24985 the object type itself or a TREE_LIST may appear as the
24986 operand 1. */
24989 /* This is an array type. We need to check array dimensions
24990 as well. */
24992 || value_dependent_expression_p
24994 else
24996 }
24999 {
25003 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
25004 contains an identifier associated by name lookup with one or more
25005 declarations declared with a dependent type, or...a
25006 nested-name-specifier or qualified-id that names a member of an
25007 unknown specialization. */
25010 }
25020 {
25021 tree elt;
25025 {
25028 }
25030 }
25032 /* A static data member of the current instantiation with incomplete
25033 array type is type-dependent, as the definition and specializations
25034 can have different bounds. */
25041 /* An array of unknown bound depending on a variadic parameter, eg:
25043 template<typename... Args>
25044 void foo (Args... args)
25045 {
25046 int arr[] = { args... };
25047 }
25049 template<int... vals>
25050 void bar ()
25051 {
25052 int arr[] = { vals... };
25053 }
25055 If the array has no length and has an initializer, it must be that
25056 we couldn't determine its length in cp_complete_array_type because
25057 it is dependent. */
25065 /* A function or variable template-id is type-dependent if it has any
25066 dependent template arguments. */
25070 {
25071 /* Consider the innermost template arguments, since those are the ones
25072 that come from the template-id; the template arguments for the
25073 enclosing class do not make it type-dependent unless they are used in
25074 the type of the decl. */
25076 && (any_dependent_template_arguments_p
25079 }
25081 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
25082 type-dependent. Checking this is important for functions with auto return
25083 type, which looks like a dependent type. */
25092 {
25096 }
25098 /* Always dependent, on the number of arguments if nothing else. */
25103 {
25108 {
25114 }
25115 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
25120 {
25125 }
25128 {
25135 }
25145 }
25149 /* Dependent type attributes might not have made it from the decl to
25150 the type yet. */
25156 }
25158 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
25159 type-dependent if the expression refers to a member of the current
25160 instantiation and the type of the referenced member is dependent, or the
25161 class member access expression refers to a member of an unknown
25162 specialization.
25164 This function returns true if the OBJECT in such a class member access
25165 expression is of an unknown specialization. */
25167 bool
25169 {
25170 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
25171 dependent. */
25176 }
25178 /* walk_tree callback function for instantiation_dependent_expression_p,
25179 below. Returns non-zero if a dependent subexpression is found. */
25181 static tree
25184 {
25186 {
25187 /* We don't have to worry about decltype currently because decltype
25188 of an instantiation-dependent expr is a dependent type. This
25189 might change depending on the resolution of DR 1172. */
25192 }
25195 {
25196 /* Don't treat an argument list as dependent just because it has no
25197 TREE_TYPE. */
25205 /* Handle expressions with type operands. */
25210 {
25215 {
25218 else
25219 {
25222 }
25223 }
25225 }
25229 /* In a template, finish_class_member_access_expr creates a
25230 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
25231 type-dependent, so that we can check access control at
25232 instantiation time (PR 42277). See also Core issue 1273. */
25239 else
25242 /* Treat statement-expressions as dependent. */
25246 /* Treat requires-expressions as dependent. */
25251 /* Treat calls to function concepts as dependent. */
25257 /* And variable concepts. */
25264 }
25268 else
25270 }
25272 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
25273 sense defined by the ABI:
25275 "An expression is instantiation-dependent if it is type-dependent
25276 or value-dependent, or it has a subexpression that is type-dependent
25277 or value-dependent."
25279 Except don't actually check value-dependence for unevaluated expressions,
25280 because in sizeof(i) we don't care about the value of i. Checking
25281 type-dependence will in turn check value-dependence of array bounds/template
25282 arguments as needed. */
25284 bool
25286 {
25287 tree result;
25298 }
25300 /* As above, but also check value-dependence of the expression as a whole. */
25302 bool
25304 {
25307 }
25309 /* Like type_dependent_expression_p, but it also works while not processing
25310 a template definition, i.e. during substitution or mangling. */
25312 bool
25314 {
25320 }
25322 /* Returns TRUE if ARGS contains a type-dependent expression. */
25324 bool
25326 {
25328 tree arg;
25331 {
25334 }
25336 }
25338 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
25339 expressions) contains any type-dependent expressions. */
25341 bool
25343 {
25349 }
25351 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
25352 expressions) contains any value-dependent expressions. */
25354 bool
25356 {
25362 }
25364 /* Returns TRUE if the ARG (a template argument) is dependent. */
25366 bool
25368 {
25372 /* Assume a template argument that was wrongly written by the user
25373 is dependent. This is consistent with what
25374 any_dependent_template_arguments_p [that calls this function]
25375 does. */
25385 {
25388 /* A member template of a dependent class is not necessarily
25389 type-dependent, but it is a dependent template argument because it
25390 will be a member of an unknown specialization to that template. */
25393 }
25395 {
25399 {
25402 }
25405 }
25408 else
25411 }
25413 /* Returns true if ARGS (a collection of template arguments) contains
25414 any types that require structural equality testing. */
25416 bool
25418 {
25428 {
25431 {
25437 {
25438 /* Look inside the argument pack. */
25441 }
25444 {
25457 }
25458 }
25459 }
25462 }
25464 /* Returns true if ARGS (a collection of template arguments) contains
25465 any dependent arguments. */
25467 bool
25469 {
25479 {
25484 }
25487 }
25489 /* Returns true if ARGS contains any errors. */
25491 bool
25493 {
25501 {
25504 else
25506 }
25512 {
25517 }
25520 }
25522 /* Returns TRUE if the template TMPL is type-dependent. */
25524 bool
25526 {
25528 {
25533 }
25535 /* Template template parameters are dependent. */
25539 /* So are names that have not been looked up. */
25543 }
25545 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
25547 bool
25549 {
25552 }
25554 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
25555 are dependent. */
25557 bool
25559 {
25566 {
25588 {
25592 }
25596 {
25600 {
25605 }
25606 }
25607 }
25610 }
25612 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
25613 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
25614 no such TYPE can be found. Note that this function peers inside
25615 uninstantiated templates and therefore should be used only in
25616 extremely limited situations. ONLY_CURRENT_P restricts this
25617 peering to the currently open classes hierarchy (which is required
25618 when comparing types). */
25620 tree
25622 {
25623 tree scope;
25624 tree name;
25625 tree decl;
25627 tree pushed_scope;
25628 tree result;
25633 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
25636 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
25637 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
25638 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
25639 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
25640 identifier of the TYPENAME_TYPE anymore.
25641 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
25642 TYPENAME_TYPE instead, we avoid messing up with a possible
25643 typedef variant case. */
25646 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
25647 it first before we can figure out what NAME refers to. */
25649 {
25651 /* Given a class template A with a dependent base with nested type C,
25652 typedef typename A::C::C C will land us here, as trying to resolve
25653 the initial A::C leads to the local C typedef, which leads back to
25654 A::C::C. So we break the recursion now. */
25656 else
25658 }
25659 /* If we don't know what SCOPE refers to, then we cannot resolve the
25660 TYPENAME_TYPE. */
25663 /* If this is a typedef, we don't want to look inside (c++/11987). */
25666 /* If SCOPE isn't the template itself, it will not have a valid
25667 TYPE_FIELDS list. */
25669 /* scope is either the template itself or a compatible instantiation
25670 like X<T>, so look up the name in the original template. */
25672 /* If scope has no fields, it can't be a current instantiation. Check this
25673 before currently_open_class to avoid infinite recursion (71515). */
25676 /* If the SCOPE is not the current instantiation, there's no reason
25677 to look inside it. */
25680 /* Enter the SCOPE so that name lookup will be resolved as if we
25681 were in the class definition. In particular, SCOPE will no
25682 longer be considered a dependent type. */
25684 /* Look up the declaration. */
25686 tf_warning_or_error);
25690 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
25691 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
25697 {
25701 }
25704 {
25705 /* Obtain the template and the arguments. */
25708 {
25709 /* We get here with a plain identifier because a previous tentative
25710 parse of the nested-name-specifier as part of a ptr-operator saw
25711 ::template X<A>. The use of ::template is necessary in a
25712 ptr-operator, but wrong in a declarator-id.
25714 [temp.names]: In a qualified-id of a declarator-id, the keyword
25715 template shall not appear at the top level. */
25719 }
25721 /* Instantiate the template. */
25727 }
25729 /* Leave the SCOPE. */
25733 /* If we failed to resolve it, return the original typename. */
25737 /* If lookup found a typename type, resolve that too. */
25739 {
25740 /* Ill-formed programs can cause infinite recursion here, so we
25741 must catch that. */
25745 }
25747 /* Qualify the resulting type. */
25753 }
25755 /* EXPR is an expression which is not type-dependent. Return a proxy
25756 for EXPR that can be used to compute the types of larger
25757 expressions containing EXPR. */
25759 tree
25761 {
25763 tree inner_expr;
25765 /* When checking, try to get a constant value for all non-dependent
25766 expressions in order to expose bugs in *_dependent_expression_p
25767 and constexpr. This can affect code generation, see PR70704, so
25768 only do this for -fchecking=2. */
25771 /* Don't do this during nsdmi parsing as it can lead to
25772 unexpected recursive instantiations. */
25774 /* Don't do this during concept expansion either and for
25775 the same reason. */
25781 /* Preserve OVERLOADs; the functions must be available to resolve
25782 types. */
25793 /* There is no need to return a proxy for a variable. */
25796 /* Preserve string constants; conversions from string constants to
25797 "char *" are allowed, even though normally a "const char *"
25798 cannot be used to initialize a "char *". */
25801 /* Preserve void and arithmetic constants, as an optimization -- there is no
25802 reason to create a new node. */
25807 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
25808 There is at least one place where we want to know that a
25809 particular expression is a throw-expression: when checking a ?:
25810 expression, there are special rules if the second or third
25811 argument is a throw-expression. */
25815 /* Don't wrap an initializer list, we need to be able to look inside. */
25819 /* Don't wrap a dummy object, we need to be able to test for it. */
25838 /* If the type is unknown, it can't really be non-dependent */
25841 /* Otherwise, build a NON_DEPENDENT_EXPR. */
25844 }
25846 /* ARGS is a vector of expressions as arguments to a function call.
25847 Replace the arguments with equivalent non-dependent expressions.
25848 This modifies ARGS in place. */
25850 void
25852 {
25854 tree arg;
25857 {
25861 }
25862 }
25864 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
25865 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
25866 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
25868 static tree
25870 {
25884 }
25886 tree
25888 {
25890 }
25892 tree
25894 {
25896 }
25898 /* Return a C++17 deduction placeholder for class template TMPL. */
25900 tree
25902 {
25906 }
25908 /* True iff T is a C++17 class template deduction placeholder. */
25910 bool
25912 {
25914 }
25916 /* Make a "constrained auto" type-specifier. This is an
25917 auto type with constraints that must be associated after
25918 deduction. The constraint is formed from the given
25919 CONC and its optional sequence of arguments, which are
25920 non-null if written as partial-concept-id. */
25922 tree
25924 {
25927 /* Build the constraint. */
25935 /* Our canonical type depends on the constraint. */
25938 /* Attach the constraint to the type declaration. */
25941 }
25943 /* Given type ARG, return std::initializer_list<ARG>. */
25945 static tree
25947 {
25951 {
25955 "deducing from brace-enclosed initializer list"
25959 }
25965 }
25967 /* Replace auto in TYPE with std::initializer_list<auto>. */
25969 static tree
25971 {
25978 }
25980 /* Hash traits for hashing possibly constrained 'auto'
25981 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
25984 {
25987 };
25989 /* Hash the 'auto' T. */
25991 inline hashval_t
25993 {
25995 /* Matching constrained-type-specifiers denote the same template
25996 parameter, so hash the constraint. */
25998 else
25999 /* But unconstrained autos are all separate, so just hash the pointer. */
26001 }
26003 /* Compare two 'auto's. */
26007 {
26014 /* Two unconstrained autos are distinct. */
26019 }
26021 /* for_each_template_parm callback for extract_autos: if t is a (possibly
26022 constrained) auto, add it to the vector. */
26024 static int
26026 {
26029 {
26030 /* All the autos were built with index 0; fix that up now. */
26034 /* If this is a repeated constrained-type-specifier, use the index we
26035 chose before. */
26037 else
26038 {
26039 /* Otherwise this is new, so use the current count. */
26042 }
26044 }
26046 /* Always keep walking. */
26048 }
26050 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
26051 says they can appear anywhere in the type. */
26053 static tree
26055 {
26064 {
26069 }
26072 }
26074 /* The stem for deduction guide names. */
26077 /* Return the name for a deduction guide for class template TMPL. */
26079 tree
26081 {
26092 }
26094 /* True if NAME is the name of a deduction guide. */
26096 bool
26098 {
26103 }
26105 /* True if FN is a deduction guide. */
26107 bool
26109 {
26114 }
26116 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
26118 bool
26120 {
26127 }
26129 /* True if FN is a guide generated from a constructor template. */
26131 bool
26133 {
26141 }
26143 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
26144 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
26145 template parameter types. Note that the handling of template template
26146 parameters relies on current_template_parms being set appropriately for the
26147 new template. */
26149 static tree
26152 {
26158 tree newtype;
26161 {
26168 }
26169 else
26170 {
26173 {
26174 // Substitute once to fix references to other template parameters.
26177 // Now substitute again to reduce the level of the auto.
26180 }
26181 else
26184 }
26186 tree newdecl
26191 tree newidx;
26194 {
26204 {
26209 // First create a copy (ttargs) of tsubst_args with an
26210 // additional level for the template template parameter's own
26211 // template parameters (ttparms).
26212 tree ttparms = (INNERMOST_TEMPLATE_PARMS
26220 // Substitute ttargs into ttparms to fix references to
26221 // other template parameters.
26224 // Now substitute again with args based on tparms, to reduce
26225 // the level of the ttparms.
26228 complain);
26229 // Finally, tack the adjusted parms onto tparms.
26231 current_template_parms);
26233 }
26234 }
26235 else
26236 {
26238 tree newconst
26250 }
26253 }
26255 /* Returns a C++17 class deduction guide template based on the constructor
26256 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
26257 guide, or REFERENCE_TYPE for an implicit copy/move guide. */
26259 static tree
26261 {
26265 location_t loc;
26269 {
26273 {
26276 }
26277 else
26287 }
26288 else
26289 {
26293 fn_tmpl
26303 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
26304 fully specialized args for the enclosing class. Strip those off, as
26305 the deduction guide won't have those template parameters. */
26308 /* Discard the 'this' parameter. */
26316 {
26319 /* For a member template constructor, we need to flatten the two
26320 template parameter lists into one, and then adjust the function
26321 signature accordingly. This gets...complicated. */
26324 /* For a member template we should have two levels of parms/args, one
26325 for the class and one for the constructor. We stripped
26326 specialized args for further enclosing classes above. */
26330 /* Template args for translating references to the two-level template
26331 parameters into references to the one-level template parameters we
26332 are creating. */
26337 /* Template parms for the constructor template. */
26340 /* Template parms for the class template. */
26344 /* Template parms for the deduction guide start as a copy of the
26345 template parms for the class. We set current_template_parms for
26346 lookup_template_class_1. */
26352 /* Now we need to rewrite the constructor parms to append them to the
26353 class parms. */
26355 {
26372 }
26374 /* Now we have a final set of template parms to substitute into the
26375 function signature. */
26384 }
26389 }
26392 {
26393 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
26397 }
26401 FUNCTION_DECL,
26418 }
26420 /* Deduce template arguments for the class template placeholder PTYPE for
26421 template TMPL based on the initializer INIT, and return the resulting
26422 type. */
26424 static tree
26426 tsubst_flags_t complain)
26427 {
26429 {
26430 /* We should have handled this in the caller. */
26436 }
26447 {
26450 {
26451 /* As an exception, the first phase in 16.3.1.7 (considering the
26452 initializer list as a single argument) is omitted if the
26453 initializer list consists of a single expression of type cv U,
26454 where U is a specialization of C or a class derived from a
26455 specialization of C. */
26466 }
26469 else
26471 }
26472 else
26483 /* Prune explicit deduction guides in copy-initialization context. */
26485 {
26491 {
26492 /* Found a nonconverting guide, prune the candidates. */
26499 }
26500 }
26505 {
26508 }
26511 // FIXME cache artificial deduction guides
26513 {
26514 /* Skip inherited constructors. */
26524 else
26528 }
26532 /* If this is list-initialization and the class has a list constructor, first
26533 try deducing from the list as a single argument, as [over.match.list]. */
26537 {
26541 }
26543 {
26549 {
26550 /* That didn't work, now try treating the list as a sequence of
26551 arguments. */
26554 }
26555 }
26557 /* Maybe generate an implicit deduction guide. */
26559 {
26563 /* Generate a copy guide. */
26566 /* Generate a default guide. */
26570 {
26575 }
26576 }
26579 {
26581 " of %qT, as it has no non-explicit deduction guides or "
26584 }
26586 {
26590 }
26593 {
26597 }
26600 {
26610 }
26615 }
26617 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
26618 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
26619 The CONTEXT determines the context in which auto deduction is performed
26620 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
26621 OUTER_TARGS are used during template argument deduction
26622 (context == adc_unify) to properly substitute the result, and is ignored
26623 in other contexts.
26625 For partial-concept-ids, extra args may be appended to the list of deduced
26626 template arguments prior to determining constraint satisfaction. */
26628 tree
26632 {
26633 tree targs;
26640 /* Defining a subset of type-dependent expressions that we can deduce
26641 from ahead of time isn't worth the trouble. */
26644 /* Similarly, we can't deduce from another undeduced decl. */
26649 /* C++17 class template argument deduction. */
26653 /* Nothing we can do with this, even in deduction context. */
26656 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
26657 with either a new invented type template parameter U or, if the
26658 initializer is a braced-init-list (8.5.4), with
26659 std::initializer_list<U>. */
26661 {
26666 else
26667 {
26669 {
26673 "for deduction to %<std::initializer_list%>, use copy-"
26675 }
26677 }
26678 }
26689 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
26690 and initializer has array type, deduce cv-qualified array type. */
26692 complain);
26694 {
26703 {
26707 }
26708 }
26709 else
26710 {
26712 tree tparms;
26716 else
26717 {
26721 }
26728 {
26730 /* Try again at instantiation time. */
26734 /* If type is error_mark_node a diagnostic must have been
26735 emitted by now. Also, having a mention to '<type error>'
26736 in the diagnostic is not really useful to the user. */
26737 {
26741 else
26746 }
26748 }
26749 }
26751 /* Check any placeholder constraints against the deduced type. */
26754 {
26755 /* Use the deduced type to check the associated constraints. If we
26756 have a partial-concept-id, rebuild the argument list so that
26757 we check using the extra arguments. */
26761 {
26764 }
26765 else
26768 {
26770 {
26772 {
26790 }
26792 }
26794 }
26795 }
26801 }
26803 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
26804 result. */
26806 tree
26808 {
26810 {
26816 /* In an abbreviated function template we didn't know we were dealing
26817 with a function template when we saw the auto return type, so update
26818 it to have the correct level. */
26820 }
26822 }
26824 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
26825 'decltype(auto)' or a deduced class template. */
26827 bool
26829 {
26835 else
26837 }
26839 /* for_each_template_parm callback for type_uses_auto. */
26841 int
26843 {
26845 }
26847 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
26848 a use of `auto'. Returns NULL_TREE otherwise. */
26850 tree
26852 {
26856 {
26857 /* The Concepts TS allows multiple autos in one type-specifier; just
26858 return the first one we find, do_auto_deduction will collect all of
26859 them. */
26863 else
26865 }
26866 else
26868 }
26870 /* Report ill-formed occurrences of auto types in ARGUMENTS. If
26871 concepts are enabled, auto is acceptable in template arguments, but
26872 only when TEMPL identifies a template class. Return TRUE if any
26873 such errors were reported. */
26875 bool
26877 {
26878 /* If there were previous errors, nevermind. */
26882 /* If TMPL is an identifier, we're parsing and we can't tell yet
26883 whether TMPL is supposed to be a type, a function or a variable.
26884 We'll only be able to tell during template substitution, so we
26885 expect to be called again then. If concepts are enabled and we
26886 know we have a type, we're ok. */
26894 /* Quickly search for any occurrences of auto; usually there won't
26895 be any, and then we'll avoid allocating the vector. */
26903 {
26908 }
26911 }
26913 /* For a given template T, return the vector of typedefs referenced
26914 in T for which access check is needed at T instantiation time.
26915 T is either a FUNCTION_DECL or a RECORD_TYPE.
26916 Those typedefs were added to T by the function
26917 append_type_to_template_for_access_check. */
26921 {
26922 tree ti;
26933 {
26938 }
26941 }
26943 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
26944 tied to T. That list of typedefs will be access checked at
26945 T instantiation time.
26946 T is either a FUNCTION_DECL or a RECORD_TYPE.
26947 TYPE_DECL is a TYPE_DECL node representing a typedef.
26948 SCOPE is the scope through which TYPE_DECL is accessed.
26949 LOCATION is the location of the usage point of TYPE_DECL.
26951 This function is a subroutine of
26952 append_type_to_template_for_access_check. */
26954 static void
26956 tree type_decl,
26957 tree scope,
26958 location_t location)
26959 {
26960 qualified_typedef_usage_t typedef_usage;
26961 tree ti;
26968 && type_decl
26982 }
26984 /* Append TYPE_DECL to the template TEMPL.
26985 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
26986 At TEMPL instanciation time, TYPE_DECL will be checked to see
26987 if it can be accessed through SCOPE.
26988 LOCATION is the location of the usage point of TYPE_DECL.
26990 e.g. consider the following code snippet:
26992 class C
26993 {
26994 typedef int myint;
26995 };
26997 template<class U> struct S
26998 {
26999 C::myint mi; // <-- usage point of the typedef C::myint
27000 };
27002 S<char> s;
27004 At S<char> instantiation time, we need to check the access of C::myint
27005 In other words, we need to check the access of the myint typedef through
27006 the C scope. For that purpose, this function will add the myint typedef
27007 and the scope C through which its being accessed to a list of typedefs
27008 tied to the template S. That list will be walked at template instantiation
27009 time and access check performed on each typedefs it contains.
27010 Note that this particular code snippet should yield an error because
27011 myint is private to C. */
27013 void
27015 tree type_decl,
27016 tree scope,
27017 location_t location)
27018 {
27024 /* Make sure we don't append the type to the template twice. */
27031 }
27033 /* Convert the generic type parameters in PARM that match the types given in the
27034 range [START_IDX, END_IDX) from the current_template_parms into generic type
27035 packs. */
27037 tree
27039 {
27050 {
27051 /* Create a distinct parameter pack type from the current parm and add it
27052 to the replacement args to tsubst below into the generic function
27053 parameter. */
27068 }
27074 /* If there are more levels then build up the replacement with the outer
27075 template parms. */
27079 replacement);
27082 }
27084 /* Entries in the decl_constraint hash table. */
27086 {
27087 tree decl;
27088 tree ci;
27089 };
27091 /* Hashing function and equality for constraint entries. */
27093 {
27095 {
27097 }
27100 {
27102 }
27103 };
27105 /* A mapping from declarations to constraint information. Note that
27106 both templates and their underlying declarations are mapped to the
27107 same constraint information.
27109 FIXME: This is defined in pt.c because garbage collection
27110 code is not being generated for constraint.cc. */
27114 /* Returns the template constraints of declaration T. If T is not
27115 constrained, return NULL_TREE. Note that T must be non-null. */
27117 tree
27119 {
27130 else
27132 }
27134 /* Associate the given constraint information CI with the declaration
27135 T. If T is a template, then the constraints are associated with
27136 its underlying declaration. Don't build associations if CI is
27137 NULL_TREE. */
27139 void
27141 {
27153 }
27155 /* Remove the associated constraints of the declaration T. */
27157 void
27159 {
27168 }
27170 /* Memoized satisfaction results for declarations. This
27171 maps the pair (constraint_info, arguments) to the result computed
27172 by constraints_satisfied_p. */
27175 {
27176 tree ci;
27177 tree args;
27178 tree result;
27179 };
27181 /* Hashing function and equality for constraint entries. */
27184 {
27186 {
27189 }
27192 {
27194 }
27195 };
27197 /* Memoized satisfaction results for concept checks. */
27200 {
27201 tree tmpl;
27202 tree args;
27203 tree result;
27204 };
27206 /* Hashing function and equality for constraint entries. */
27209 {
27211 {
27213 }
27216 {
27221 }
27222 };
27227 /* Search for a memoized satisfaction result. Returns one of the
27228 truth value nodes if previously memoized, or NULL_TREE otherwise. */
27230 tree
27232 {
27237 else
27239 }
27241 /* Memoize the result of a satisfication test. Returns the saved result. */
27243 tree
27245 {
27252 }
27254 /* Search for a memoized satisfaction result for a concept. */
27256 tree
27258 {
27263 else
27265 }
27267 /* Memoize the result of a concept check. Returns the saved result. */
27269 tree
27271 {
27278 }
27282 /* Returns a prior concept specialization. This returns the substituted
27283 and normalized constraints defined by the concept. */
27285 tree
27287 {
27292 else
27294 }
27296 /* Save a concept expansion for later. */
27298 tree
27300 {
27307 }
27309 static hashval_t
27311 {
27320 }
27322 /* Compare the constraints of two subsumption entries. The LEFT1 and
27323 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
27324 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
27326 static bool
27328 {
27336 }
27338 /* Key/value pair for learning and memoizing subsumption results. This
27339 associates a pair of check constraints (including arguments) with
27340 a boolean value indicating the result. */
27343 {
27344 tree t1;
27345 tree t2;
27347 };
27349 /* Hashing function and equality for constraint entries. */
27352 {
27354 {
27356 }
27359 {
27364 }
27365 };
27369 /* Search for a previously cached subsumption result. */
27373 {
27378 else
27380 }
27382 /* Save a subsumption result. */
27384 bool
27386 {
27393 }
27395 /* Set up the hash table for constraint association. */
27397 void
27399 {
27408 }
27410 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
27411 0..N-1. */
27413 void
27415 {
27418 integer_type_node,
27419 NULL_TREE),
27423 }
27425 /* Set up the hash tables for template instantiations. */
27427 void
27429 {
27435 }
27437 /* Print stats about the template hash tables for -fstats. */
27439 void
27441 {
27450 }
27452 #if CHECKING_P
27456 /* Verify that build_non_dependent_expr () works, for various expressions,
27457 and that location wrappers don't affect the results. */
27459 static void
27461 {
27464 /* Verify constants, without and with location wrappers. */
27481 }
27483 /* Verify that type_dependent_expression_p () works correctly, even
27484 in the presence of location wrapper nodes. */
27486 static void
27488 {
27493 /* If no templates are involved, nothing is type-dependent. */
27499 /* Within a template, an unresolved name is always type-dependent. */
27502 /* Ensure it copes with NULL_TREE and errors. */
27506 /* A USING_DECL in a template should be type-dependent, even if wrapped
27507 with a location wrapper (PR c++/83799). */
27516 }
27518 /* Run all of the selftests within this file. */
27520 void
27522 {
27525 }