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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);
2534 }
2536 /* Return the number of template headers we expect to see for a definition
2537 or specialization of CTYPE or one of its non-template members. */
2539 int
2541 {
2545 {
2546 /* You're supposed to have one `template <...>' for every
2547 template class, but you don't need one for a full
2548 specialization. For example:
2550 template <class T> struct S{};
2551 template <> struct S<int> { void f(); };
2552 void S<int>::f () {}
2554 is correct; there shouldn't be a `template <>' for the
2555 definition of `S<int>::f'. */
2557 /* If CTYPE does not have template information of any
2558 kind, then it is not a template, nor is it nested
2559 within a template. */
2567 }
2570 }
2572 /* Do a simple sanity check on the template headers that precede the
2573 variable declaration DECL. */
2575 void
2577 {
2582 {
2585 "variable templates only available with "
2588 // Namespace-scope variable templates should have a template header.
2590 }
2592 {
2594 "too many template headers for %qD "
2600 "members of an explicitly specialized class are defined "
2602 }
2603 }
2605 /* An explicit specialization whose declarator-id or class-head-name is not
2606 qualified shall be declared in the nearest enclosing namespace of the
2607 template, or, if the namespace is inline (7.3.1), any namespace from its
2608 enclosing namespace set.
2610 If the name declared in the explicit instantiation is an unqualified name,
2611 the explicit instantiation shall appear in the namespace where its template
2612 is declared or, if that namespace is inline (7.3.1), any namespace from its
2613 enclosing namespace set. */
2615 void
2617 {
2622 {
2628 /* This was allowed in C++98, so only pedwarn. */
2630 "outside its namespace must use a nested-name-"
2632 }
2633 }
2635 /* Warn for a template specialization SPEC that is missing some of a set
2636 of function or type attributes that the template TEMPL is declared with.
2637 ATTRLIST is a list of additional attributes that SPEC should be taken
2638 to ultimately be declared with. */
2640 static void
2642 {
2649 /* Avoid warning if either declaration or its type is deprecated. */
2671 /* Avoid warning if the primary has no attributes. */
2675 /* Avoid warning if either declaration contains an attribute on
2676 the white list below. */
2679 };
2687 /* Avoid warning if the difference between the primary and
2688 the specialization is not in one of the attributes below. */
2692 };
2694 /* Put together a list of the black listed attributes that the primary
2695 template is declared with that the specialization is not, in case
2696 it's not apparent from the most recent declaration of the primary. */
2698 pretty_printer str;
2701 {
2703 {
2708 {
2718 }
2719 }
2720 }
2727 spec))
2733 }
2735 /* Check to see if the function just declared, as indicated in
2736 DECLARATOR, and in DECL, is a specialization of a function
2737 template. We may also discover that the declaration is an explicit
2738 instantiation at this point.
2740 Returns DECL, or an equivalent declaration that should be used
2741 instead if all goes well. Issues an error message if something is
2742 amiss. Returns error_mark_node if the error is not easily
2743 recoverable.
2745 FLAGS is a bitmask consisting of the following flags:
2747 2: The function has a definition.
2748 4: The function is a friend.
2750 The TEMPLATE_COUNT is the number of references to qualifying
2751 template classes that appeared in the name of the function. For
2752 example, in
2754 template <class T> struct S { void f(); };
2755 void S<int>::f();
2757 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2758 classes are not counted in the TEMPLATE_COUNT, so that in
2760 template <class T> struct S {};
2761 template <> struct S<int> { void f(); }
2762 template <> void S<int>::f();
2764 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2765 invalid; there should be no template <>.)
2767 If the function is a specialization, it is marked as such via
2768 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2769 is set up correctly, and it is added to the list of specializations
2770 for that template. */
2772 tree
2774 tree decl,
2777 tree attrlist)
2778 {
2787 tmpl_spec_kind tsk;
2790 {
2793 else
2795 }
2796 else
2800 {
2803 {
2806 }
2808 {
2810 /* This could be something like:
2812 template <class T> void f(T);
2813 class S { friend void f<>(int); } */
2815 else
2816 {
2817 /* This case handles bogus declarations like template <>
2818 template <class T> void f<int>(); */
2821 declarator);
2823 }
2824 }
2828 /* The error has already been reported in
2829 check_specialization_scope. */
2835 /* Fall through. */
2848 decl);
2851 else
2855 /* Fall through. */
2861 /* In cases like template<> constexpr bool v = true;
2862 We'll give an error in check_template_variable. */
2868 else
2874 {
2875 /* This case handles bogus declarations like template <>
2876 template <class T> void f<int>(); */
2880 declarator);
2882 {
2883 /* Partial specialization of variable template. */
2887 }
2891 else
2895 ok:;
2896 }
2899 /* This is a specialization of a member template, without
2900 specialization the containing class. Something like:
2902 template <class T> struct S {
2903 template <class U> void f (U);
2904 };
2905 template <> template <class U> void S<int>::f(U) {}
2907 That's a specialization -- but of the entire template. */
2913 }
2916 /* This doesn't apply to variable templates. */
2919 {
2923 {
2927 }
2928 }
2931 {
2936 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2938 {
2939 tree fns;
2944 else
2945 {
2946 /* If there is no class context, the explicit instantiation
2947 must be at namespace scope. */
2950 /* Find the namespace binding, using the declaration
2951 context. */
2955 /* If lookup fails, look for a friend declaration so we can
2956 give a better diagnostic. */
2962 {
2965 }
2966 }
2969 }
2975 {
2977 /* A specialization in class scope. This is invalid,
2978 but the error will already have been flagged by
2979 check_specialization_scope. */
2981 else
2982 {
2983 /* It's not valid to write an explicit instantiation in
2984 class scope, e.g.:
2986 class C { template void f(); }
2988 This case is caught by the parser. However, on
2989 something like:
2991 template class C { void f(); };
2993 (which is invalid) we can get here. The error will be
2994 issued later. */
2995 ;
2996 }
2999 }
3002 {
3003 // We'll match variable templates in start_decl.
3007 /* Find the list of functions in ctype that have the same
3008 name as the declared function. */
3012 {
3016 {
3017 /* From [temp.expl.spec]:
3019 If such an explicit specialization for the member
3020 of a class template names an implicitly-declared
3021 special member function (clause _special_), the
3022 program is ill-formed.
3024 Similar language is found in [temp.explicit]. */
3027 }
3030 }
3032 /* For a type-conversion operator, We might be looking for
3033 `operator int' which will be a specialization of
3034 `operator T'. Grab all the conversion operators, and
3035 then select from them. */
3040 {
3043 }
3044 else
3046 }
3048 /* Figure out what exactly is being specialized at this point.
3049 Note that for an explicit instantiation, even one for a
3050 member function, we cannot tell a priori whether the
3051 instantiation is for a member template, or just a member
3052 function of a template class. Even if a member template is
3053 being instantiated, the member template arguments may be
3054 elided if they can be deduced from the rest of the
3055 declaration. */
3058 member_specialization,
3059 template_count,
3060 tsk);
3063 /* We couldn't figure out what this declaration was
3064 specializing. */
3066 else
3067 {
3070 {
3072 "friend declaration %qD is not visible to "
3076 }
3084 {
3085 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3086 is done by do_decl_instantiation later. */
3092 {
3093 /* If TMPL is not the most general template (for
3094 example, if TMPL is a friend template that is
3095 injected into namespace scope), then there will
3096 be too many levels of TARGS. Remove some of them
3097 here. */
3099 tree new_targs;
3106 }
3109 }
3111 /* If we thought that the DECL was a member function, but it
3112 turns out to be specializing a static member function,
3113 make DECL a static member function as well. */
3119 /* If this is a specialization of a member template of a
3120 template class, we want to return the TEMPLATE_DECL, not
3121 the specialization of it. */
3123 {
3128 {
3129 tree parm;
3133 /* We want to use the argument list specified in the
3134 definition, not in the original declaration. */
3139 }
3142 }
3144 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3150 /* Inherit default function arguments from the template
3151 DECL is specializing. */
3155 /* This specialization has the same protection as the
3156 template it specializes. */
3160 /* 7.1.1-1 [dcl.stc]
3162 A storage-class-specifier shall not be specified in an
3163 explicit specialization...
3165 The parser rejects these, so unless action is taken here,
3166 explicit function specializations will always appear with
3167 global linkage.
3169 The action recommended by the C++ CWG in response to C++
3170 defect report 605 is to make the storage class and linkage
3171 of the explicit specialization match the templated function:
3173 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3174 */
3176 {
3180 /* A concept cannot be specialized. */
3182 {
3184 gen_tmpl);
3186 }
3188 /* This specialization has the same linkage and visibility as
3189 the function template it specializes. */
3192 {
3195 }
3198 {
3201 }
3202 }
3204 /* If DECL is a friend declaration, declared using an
3205 unqualified name, the namespace associated with DECL may
3206 have been set incorrectly. For example, in:
3208 template <typename T> void f(T);
3209 namespace N {
3210 struct S { friend void f<int>(int); }
3211 }
3213 we will have set the DECL_CONTEXT for the friend
3214 declaration to N, rather than to the global namespace. */
3219 /* This is not really a declaration of a specialization.
3220 It's just the name of an instantiation. But, it's not
3221 a request for an instantiation, either. */
3224 /* A specialization is not necessarily COMDAT. */
3230 /* If this is a full specialization, register it so that we can find
3231 it again. Partial specializations will be registered in
3232 process_partial_specialization. */
3234 {
3239 }
3242 /* A 'structor should already have clones. */
3248 }
3249 }
3252 }
3254 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3255 parameters. These are represented in the same format used for
3256 DECL_TEMPLATE_PARMS. */
3258 int
3260 {
3261 const_tree p1;
3262 const_tree p2;
3270 {
3282 {
3286 /* If either of the template parameters are invalid, assume
3287 they match for the sake of error recovery. */
3300 }
3301 }
3304 /* One set of parameters has more parameters lists than the
3305 other. */
3309 }
3311 /* Determine whether PARM is a parameter pack. */
3313 bool
3315 {
3316 /* Determine if we have a non-type template parameter pack. */
3323 /* If this is a list of template parameters, we could get a
3324 TYPE_DECL or a TEMPLATE_DECL. */
3328 /* Otherwise it must be a type template parameter. */
3332 }
3334 /* Determine if T is a function parameter pack. */
3336 bool
3338 {
3342 }
3344 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3345 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3347 tree
3349 {
3356 }
3358 /* Return true iff the function parameter PARAM_DECL was expanded
3359 from the function parameter pack PACK. */
3361 bool
3363 {
3368 /* The parameter pack and its pack arguments have the same
3369 DECL_PARM_INDEX. */
3371 }
3373 /* Determine whether ARGS describes a variadic template args list,
3374 i.e., one that is terminated by a template argument pack. */
3376 static bool
3378 {
3380 tree last_parm;
3394 }
3396 /* Generate a new name for the parameter pack name NAME (an
3397 IDENTIFIER_NODE) that incorporates its */
3399 static tree
3401 {
3402 /* Munge the name to include the parameter index. */
3403 #define NUMBUF_LEN 128
3417 }
3419 /* Return true if T is a primary function, class or alias template
3420 specialization, not including the template pattern. */
3422 bool
3424 {
3440 }
3442 /* Return true if PARM is a template template parameter. */
3444 bool
3446 {
3448 }
3450 /* Return true iff PARM is a DECL representing a type template
3451 parameter. */
3453 bool
3455 {
3460 }
3462 /* Return the template parameters of T if T is a
3463 primary template instantiation, NULL otherwise. */
3465 tree
3467 {
3472 parms = INNERMOST_TEMPLATE_PARMS
3476 }
3478 /* Return the template parameters of the LEVELth level from the full list
3479 of template parameters PARMS. */
3481 tree
3483 {
3484 tree p;
3495 }
3497 /* Returns the template arguments of T if T is a template instantiation,
3498 NULL otherwise. */
3500 tree
3502 {
3510 }
3512 /* Return the argument pack elements of T if T is a template argument pack,
3513 NULL otherwise. */
3515 tree
3517 {
3523 }
3525 /* In an ARGUMENT_PACK_SELECT, the actual underlying argument that the
3526 ARGUMENT_PACK_SELECT represents. */
3528 static tree
3530 {
3534 /* If the selected argument is an expansion E, that most likely means we were
3535 called from gen_elem_of_pack_expansion_instantiation during the
3536 substituting of an argument pack (of which the Ith element is a pack
3537 expansion, where I is ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
3538 In this case, the Ith element resulting from this substituting is going to
3539 be a pack expansion, which pattern is the pattern of E. Let's return the
3540 pattern of E, and gen_elem_of_pack_expansion_instantiation will build the
3541 resulting pack expansion from it. */
3543 {
3544 /* Make sure we aren't throwing away arg info. */
3547 }
3550 }
3553 /* True iff FN is a function representing a built-in variadic parameter
3554 pack. */
3556 bool
3558 {
3568 }
3570 /* True iff CALL is a call to a function representing a built-in variadic
3571 parameter pack. */
3573 static bool
3575 {
3579 }
3581 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3583 static tree
3585 tree in_decl)
3586 {
3592 {
3594 {
3597 }
3602 }
3603 else
3604 {
3608 /* Calculate the largest value of len that won't make the size of the vec
3609 overflow an int. The compiler will exceed resource limits long before
3610 this, but it seems a decent place to diagnose. */
3614 {
3619 }
3627 }
3628 }
3630 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3631 CALL. */
3633 static tree
3635 tree in_decl)
3636 {
3646 }
3648 /* Structure used to track the progress of find_parameter_packs_r. */
3649 struct find_parameter_pack_data
3650 {
3651 /* TREE_LIST that will contain all of the parameter packs found by
3652 the traversal. */
3655 /* Set of AST nodes that have been visited by the traversal. */
3658 /* True iff we're making a type pack expansion. */
3660 };
3662 /* Identifies all of the argument packs that occur in a template
3663 argument and appends them to the TREE_LIST inside DATA, which is a
3664 find_parameter_pack_data structure. This is a subroutine of
3665 make_pack_expansion and uses_parameter_packs. */
3666 static tree
3668 {
3674 /* Handle type aliases/typedefs. */
3676 {
3683 }
3685 /* Identify whether this is a parameter pack or not. */
3687 {
3695 /* FALLTHRU */
3697 /* If the placeholder appears in the decl-specifier-seq of a function
3698 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3699 is a pack expansion, the invented template parameter is a template
3700 parameter pack. */
3710 {
3711 /* We don't want to walk into the type of a PARM_DECL,
3712 because we don't want to see the type parameter pack. */
3715 }
3720 {
3721 /* We don't want to walk into the type of a variadic capture proxy,
3722 because we don't want to see the type parameter pack. */
3725 }
3727 {
3729 find_parameter_packs_r,
3732 }
3744 /* Not a parameter pack. */
3746 }
3749 {
3750 /* Add this parameter pack to the list. */
3752 }
3758 /* This switch statement will return immediately if we don't find a
3759 parameter pack. */
3761 {
3766 /* Check the template itself. */
3769 /* Check the template arguments. */
3783 /* Ignore the declaration of a capture proxy for a parameter pack. */
3791 /* Fall through. */
3836 {
3837 /* Look at explicit captures. */
3842 /* Since we defer implicit capture, look in the body as well. */
3848 }
3851 {
3852 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3853 type_pack_expansion_p to false so that any placeholders
3854 within the expression don't get marked as parameter packs. */
3862 }
3866 }
3869 }
3871 /* Determines if the expression or type T uses any parameter packs. */
3872 bool
3874 {
3883 }
3885 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3886 representation a base-class initializer into a parameter pack
3887 expansion. If all goes well, the resulting node will be an
3888 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3889 respectively. */
3890 tree
3892 {
3893 tree result;
3902 {
3903 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3904 class initializer. In this case, the TREE_PURPOSE will be a
3905 _TYPE node (representing the base class expansion we're
3906 initializing) and the TREE_VALUE will be a TREE_LIST
3907 containing the initialization arguments.
3909 The resulting expansion looks somewhat different from most
3910 expansions. Rather than returning just one _EXPANSION, we
3911 return a TREE_LIST whose TREE_PURPOSE is a
3912 TYPE_PACK_EXPANSION containing the bases that will be
3913 initialized. The TREE_VALUE will be identical to the
3914 original TREE_VALUE, which is a list of arguments that will
3915 be passed to each base. We do not introduce any new pack
3916 expansion nodes into the TREE_VALUE (although it is possible
3917 that some already exist), because the TREE_PURPOSE and
3918 TREE_VALUE all need to be expanded together with the same
3919 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3920 resulting TREE_PURPOSE will mention the parameter packs in
3921 both the bases and the arguments to the bases. */
3922 tree purpose;
3923 tree value;
3926 /* Determine which parameter packs will be used by the base
3927 class expansion. */
3936 {
3939 arg);
3942 }
3945 {
3946 /* Collect the sets of parameter packs used in each of the
3947 initialization arguments. */
3949 {
3950 /* Determine which parameter packs will be expanded in this
3951 argument. */
3954 }
3955 }
3959 /* Create the pack expansion type for the base type. */
3965 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3966 they will rarely be compared to anything. */
3970 }
3975 /* Build the PACK_EXPANSION_* node. */
3976 result = for_types
3981 {
3982 /* Propagate type and const-expression information. */
3985 /* Mark this read now, since the expansion might be length 0. */
3987 }
3988 else
3989 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3990 they will rarely be compared to anything. */
3993 /* Determine which parameter packs will be expanded. */
4000 /* Make sure we found some parameter packs. */
4002 {
4004 {
4007 else
4009 }
4011 }
4017 }
4019 /* Checks T for any "bare" parameter packs, which have not yet been
4020 expanded, and issues an error if any are found. This operation can
4021 only be done on full expressions or types (e.g., an expression
4022 statement, "if" condition, etc.), because we could have expressions like:
4024 foo(f(g(h(args)))...)
4026 where "args" is a parameter pack. check_for_bare_parameter_packs
4027 should not be called for the subexpressions args, h(args),
4028 g(h(args)), or f(g(h(args))), because we would produce erroneous
4029 error messages.
4031 Returns TRUE and emits an error if there were bare parameter packs,
4032 returns FALSE otherwise. */
4033 bool
4035 {
4042 /* A lambda might use a parameter pack from the containing context. */
4057 {
4061 {
4072 else
4077 else
4081 }
4084 }
4087 }
4089 /* Expand any parameter packs that occur in the template arguments in
4090 ARGS. */
4091 tree
4093 {
4102 /* First, determine if we need to expand anything, and the number of
4103 slots we'll need. */
4105 {
4110 {
4114 else
4116 }
4117 else
4118 {
4120 num_result_args++;
4121 }
4122 }
4124 /* If no expansion is necessary, we're done. */
4128 /* Expand arguments. */
4131 non_default_args_count =
4134 {
4137 {
4144 }
4145 else
4146 {
4149 }
4150 }
4154 }
4156 /* Checks if DECL shadows a template parameter.
4158 [temp.local]: A template-parameter shall not be redeclared within its
4159 scope (including nested scopes).
4161 Emits an error and returns TRUE if the DECL shadows a parameter,
4162 returns FALSE otherwise. */
4164 bool
4166 {
4167 tree olddecl;
4169 /* If we're not in a template, we can't possibly shadow a template
4170 parameter. */
4174 /* Figure out what we're shadowing. */
4178 /* If there's no previous binding for this name, we're not shadowing
4179 anything, let alone a template parameter. */
4183 /* If we're not shadowing a template parameter, we're done. Note
4184 that OLDDECL might be an OVERLOAD (or perhaps even an
4185 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4186 node. */
4190 /* We check for decl != olddecl to avoid bogus errors for using a
4191 name inside a class. We check TPFI to avoid duplicate errors for
4192 inline member templates. */
4198 /* Don't complain about the injected class name, as we've already
4199 complained about the class itself. */
4206 else
4211 }
4213 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4214 ORIG_LEVEL, DECL, and TYPE. */
4216 static tree
4220 tree decl,
4221 tree type)
4222 {
4233 }
4235 /* Find the canonical type parameter for the given template type
4236 parameter. Returns the canonical type parameter, which may be TYPE
4237 if no such parameter existed. */
4239 static tree
4241 {
4242 tree list;
4256 else
4257 {
4261 }
4262 }
4264 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4265 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4266 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4267 new one is created. */
4269 static tree
4271 tsubst_flags_t complain)
4272 {
4277 {
4296 /* Template template parameters need this. */
4298 {
4305 }
4306 }
4309 }
4311 /* Process information from new template parameter PARM and append it
4312 to the LIST being built. This new parameter is a non-type
4313 parameter iff IS_NON_TYPE is true. This new parameter is a
4314 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4315 is in PARM_LOC. */
4317 tree
4320 {
4329 {
4333 {
4337 else
4339 }
4342 }
4345 {
4351 {
4352 /* [temp.param]
4354 The top-level cv-qualifiers on the template-parameter are
4355 ignored when determining its type. */
4360 && !is_parameter_pack
4361 /* If we're in a nested template parameter list, the template
4362 template parameter could be a parameter pack. */
4364 {
4365 /* This template parameter is not a parameter pack, but it
4366 should be. Complain about "bare" parameter packs. */
4369 /* Recover by calling this a parameter pack. */
4371 }
4372 }
4374 /* A template parameter is not modifiable. */
4383 processing_template_decl,
4388 }
4389 else
4390 {
4391 tree t;
4395 {
4397 /* This is for distinguishing between real templates and template
4398 template parameters */
4402 }
4403 else
4404 {
4406 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4409 }
4416 processing_template_decl,
4420 }
4424 /* Build requirements for the type/template parameter.
4425 This must be done after SET_DECL_TEMPLATE_PARM_P or
4426 process_template_parm could fail. */
4434 /* Build the parameter node linking the parameter declaration,
4435 its default argument (if any), and its constraints (if any). */
4440 }
4442 /* The end of a template parameter list has been reached. Process the
4443 tree list into a parameter vector, converting each parameter into a more
4444 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4445 as PARM_DECLs. */
4447 tree
4449 {
4454 /* Pop the dummy parameter level and add the real one. */
4457 current_template_parms
4462 {
4466 }
4471 }
4473 // Explicitly indicate the end of the template parameter list. We assume
4474 // that the current template parameters have been constructed and/or
4475 // managed explicitly, as when creating new template template parameters
4476 // from a shorthand constraint.
4477 void
4479 {
4481 }
4483 /* end_template_decl is called after a template declaration is seen. */
4485 void
4487 {
4493 /* This matches the pushlevel in begin_template_parm_list. */
4498 }
4500 /* Takes a TREE_LIST representing a template parameter and convert it
4501 into an argument suitable to be passed to the type substitution
4502 functions. Note that If the TREE_LIST contains an error_mark
4503 node, the returned argument is error_mark_node. */
4505 tree
4507 {
4520 {
4524 {
4525 /* Turn this argument into a TYPE_ARGUMENT_PACK
4526 with a single element, which expands T. */
4535 }
4536 }
4537 else
4538 {
4542 {
4543 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4544 with a single element, which expands T. */
4554 }
4555 else
4557 }
4559 }
4561 /* Given a single level of template parameters (a TREE_VEC), return it
4562 as a set of template arguments. */
4564 static tree
4566 {
4576 }
4578 /* Given a set of template parameters, return them as a set of template
4579 arguments. The template parameters are represented as a TREE_VEC, in
4580 the form documented in cp-tree.h for template arguments. */
4582 static tree
4584 {
4585 tree header;
4590 /* If there is only one level of template parameters, we do not
4591 create a TREE_VEC of TREE_VECs. Instead, we return a single
4592 TREE_VEC containing the arguments. */
4597 {
4602 else
4604 }
4607 }
4609 /* Within the declaration of a template, return the currently active
4610 template parameters as an argument TREE_VEC. */
4612 static tree
4614 {
4616 }
4618 /* Update the declared TYPE by doing any lookups which were thought to be
4619 dependent, but are not now that we know the SCOPE of the declarator. */
4621 tree
4623 {
4634 /* Don't bother building up the args in this case. */
4636 {
4637 /* tsubst in the args corresponding to the template parameters,
4638 including auto if present. Most things will be unchanged, but
4639 make_typename_type and tsubst_qualified_id will resolve
4640 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4643 tree pushed;
4645 {
4649 }
4654 }
4660 {
4663 else
4665 }
4667 }
4669 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4670 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4671 the new template is a member template. */
4673 static tree
4675 {
4684 }
4686 struct template_parm_data
4687 {
4688 /* The level of the template parameters we are currently
4689 processing. */
4692 /* The index of the specialization argument we are currently
4693 processing. */
4696 /* An array whose size is the number of template parameters. The
4697 elements are nonzero if the parameter has been used in any one
4698 of the arguments processed so far. */
4701 /* An array whose size is the number of template arguments. The
4702 elements are nonzero if the argument makes use of template
4703 parameters of this level. */
4705 };
4707 /* Subroutine of push_template_decl used to see if each template
4708 parameter in a partial specialization is used in the explicit
4709 argument list. If T is of the LEVEL given in DATA (which is
4710 treated as a template_parm_data*), then DATA->PARMS is marked
4711 appropriately. */
4713 static int
4715 {
4723 {
4726 }
4728 /* In C++17 the type of a non-type argument is a deduced context. */
4733 data,
4734 NULL,
4737 /* Return zero so that for_each_template_parm will continue the
4738 traversal of the tree; we want to mark *every* template parm. */
4740 }
4742 /* Process the partial specialization DECL. */
4744 static tree
4746 {
4753 tree inner_parms;
4754 tree inst;
4764 /* A concept cannot be specialized. */
4766 {
4769 }
4774 /* We check that each of the template parameters given in the
4775 partial specialization is used in the argument list to the
4776 specialization. For example:
4778 template <class T> struct S;
4779 template <class T> struct S<T*>;
4781 The second declaration is OK because `T*' uses the template
4782 parameter T, whereas
4784 template <class T> struct S<int>;
4786 is no good. Even trickier is:
4788 template <class T>
4789 struct S1
4790 {
4791 template <class U>
4792 struct S2;
4793 template <class U>
4794 struct S2<T>;
4795 };
4797 The S2<T> declaration is actually invalid; it is a
4798 full-specialization. Of course,
4800 template <class U>
4801 struct S2<T (*)(U)>;
4803 or some such would have been OK. */
4811 {
4816 NULL,
4818 }
4821 {
4822 /* One of the template parms was not used in a deduced context in the
4823 specialization. */
4825 {
4829 }
4833 }
4838 /* [temp.class.spec]
4840 The argument list of the specialization shall not be identical to
4841 the implicit argument list of the primary template. */
4842 tree main_args
4845 && (!flag_concepts
4848 {
4851 "any template arguments; to define the primary template, "
4853 else
4855 "template arguments and is not more constrained than "
4856 "the primary template; to define the primary template, "
4859 }
4861 /* A partial specialization that replaces multiple parameters of the
4862 primary template with a pack expansion is less specialized for those
4863 parameters. */
4865 {
4867 "primary template because it replaces multiple parameters "
4870 /* Avoid crash in process_partial_specialization. */
4872 }
4874 /* If we aren't in a dependent class, we can actually try deduction. */
4876 /* FIXME we should be able to handle a partial specialization of a
4877 partial instantiation, but currently we can't (c++/41727). */
4880 {
4884 maintmpl);
4885 }
4887 /* [temp.class.spec]
4889 A partially specialized non-type argument expression shall not
4890 involve template parameters of the partial specialization except
4891 when the argument expression is a simple identifier.
4893 The type of a template parameter corresponding to a specialized
4894 non-type argument shall not be dependent on a parameter of the
4895 specialization.
4897 Also, we verify that pack expansions only occur at the
4898 end of the argument list. */
4902 {
4909 {
4910 /* Extract the arguments from the argument pack. We'll be
4911 iterating over these in the following loop. */
4914 }
4917 {
4919 /* Get the Jth argument in the parameter pack. */
4923 {
4924 /* Pack expansions must come at the end of the
4925 argument list. */
4928 {
4932 else
4935 }
4936 }
4939 /* We only care about the pattern. */
4945 /* This next two lines are the `argument expression is not just a
4946 simple identifier' condition and also the `specialized
4947 non-type argument' bit. */
4951 {
4955 arg);
4956 else
4957 {
4958 /* Look at the corresponding template parameter,
4959 marking which template parameters its type depends
4960 upon. */
4964 {
4965 /* We haven't yet initialized TPD2. Do so now. */
4967 /* The number of parameters here is the number in the
4968 main template, which, as checked in the assertion
4969 above, is NARGS. */
4973 }
4975 /* Mark the template parameters. But this time, we're
4976 looking for the template parameters of the main
4977 template, not in the specialization. */
4984 NULL,
4988 {
4989 /* The type depended on some template parameters.
4990 If they are fully specialized in the
4991 specialization, that's OK. */
5000 "type %qT of template argument %qE depends "
5002 "type %qT of template argument %qE depends "
5004 type,
5005 arg);
5006 }
5007 }
5008 }
5009 }
5010 }
5012 /* We should only get here once. */
5016 // Build the template decl.
5025 /* Give template template parms a DECL_CONTEXT of the template
5026 for which they are a parameter. */
5028 {
5032 }
5035 /* We didn't register this in check_explicit_specialization so we could
5036 wait until the constraints were set. */
5038 else
5048 {
5054 {
5062 "declaration of %qD ambiguates earlier template "
5066 "partial specialization of %qD after instantiation "
5068 }
5069 }
5072 }
5074 /* PARM is a template parameter of some form; return the corresponding
5075 TEMPLATE_PARM_INDEX. */
5077 static tree
5079 {
5092 }
5094 /* Subroutine of fixed_parameter_pack_p below. Look for any template
5095 parameter packs used by the template parameter PARM. */
5097 static void
5099 {
5100 /* A type parm can't refer to another parm. */
5104 {
5108 }
5115 }
5117 /* PARM is a template parameter pack. Return any parameter packs used in
5118 its type or the type of any of its template parameters. If there are
5119 any such packs, it will be instantiated into a fixed template parameter
5120 list by partial instantiation rather than be fully deduced. */
5122 tree
5124 {
5125 /* This can only be true in a member template. */
5128 /* This can only be true for a parameter pack. */
5131 /* A type parm can't refer to another parm. */
5145 }
5147 /* Check that a template declaration's use of default arguments and
5148 parameter packs is not invalid. Here, PARMS are the template
5149 parameters. IS_PRIMARY is true if DECL is the thing declared by
5150 a primary template. IS_PARTIAL is true if DECL is a partial
5151 specialization.
5153 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
5154 function template declaration or a friend class template
5155 declaration. In the function case, 1 indicates a declaration, 2
5156 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
5157 emitted for extraneous default arguments.
5159 Returns TRUE if there were no errors found, FALSE otherwise. */
5161 bool
5164 {
5167 tree parm_level;
5170 /* [temp.param]
5172 A default template-argument shall not be specified in a
5173 function template declaration or a function template definition, nor
5174 in the template-parameter-list of the definition of a member of a
5175 class template. */
5179 /* You can't have a function template declaration in a local
5180 scope, nor you can you define a member of a class template in a
5181 local scope. */
5189 /* A lambda doesn't have an explicit declaration; don't complain
5190 about the parms of the enclosing class. */
5197 /* If this is either a friend defined in the scope of the class
5198 or a member function. */
5204 /* And, if it was a member function, it really was defined in
5205 the scope of the class. */
5208 /* We already checked these parameters when the template was
5209 declared, so there's no need to do it again now. This function
5210 was defined in class scope, but we're processing its body now
5211 that the class is complete. */
5214 /* Core issue 226 (C++0x only): the following only applies to class
5215 templates. */
5218 {
5219 /* [temp.param]
5221 If a template-parameter has a default template-argument, all
5222 subsequent template-parameters shall have a default
5223 template-argument supplied. */
5225 {
5232 {
5242 {
5244 /* For better subsequent error-recovery, we indicate that
5245 there should have been a default argument. */
5248 }
5250 && !is_friend_decl
5251 /* Don't complain about an enclosing partial
5252 specialization. */
5257 /* A fixed parameter pack will be partially
5258 instantiated into a fixed length list. */
5260 {
5261 /* A primary class template can only have one
5262 parameter pack, at the end of the template
5263 parameter list. */
5271 }
5272 }
5273 }
5274 }
5277 || is_partial
5278 || !is_primary
5280 /* For an ordinary class template, default template arguments are
5281 allowed at the innermost level, e.g.:
5282 template <class T = int>
5283 struct S {};
5284 but, in a partial specialization, they're not allowed even
5285 there, as we have in [temp.class.spec]:
5287 The template parameter list of a specialization shall not
5288 contain default template argument values.
5290 So, for a partial specialization, or for a function template
5291 (in C++98/C++03), we look at all of them. */
5292 ;
5293 else
5294 /* But, for a primary class template that is not a partial
5295 specialization we look at all template parameters except the
5296 innermost ones. */
5299 /* Figure out what error message to issue. */
5314 else
5315 /* Per [temp.param]/9, "A default template-argument shall not be
5316 specified in the template-parameter-lists of the definition of
5317 a member of a class template that appears outside of the member's
5318 class.", thus if we aren't handling a member of a class template
5319 there is no need to examine the parameters. */
5323 /* If we're inside a class definition, there's no need to
5324 examine the parameters to the class itself. On the one
5325 hand, they will be checked when the class is defined, and,
5326 on the other, default arguments are valid in things like:
5327 template <class T = double>
5328 struct S { template <class U> void f(U); };
5329 Here the default argument for `S' has no bearing on the
5330 declaration of `f'. */
5332 else
5333 /* Check everything. */
5339 {
5346 {
5351 {
5353 {
5360 }
5362 /* Clear out the default argument so that we are not
5363 confused later. */
5365 }
5366 }
5368 /* At this point, if we're still interested in issuing messages,
5369 they must apply to classes surrounding the object declared. */
5373 }
5376 }
5378 /* Worker for push_template_decl_real, called via
5379 for_each_template_parm. DATA is really an int, indicating the
5380 level of the parameters we are interested in. If T is a template
5381 parameter of that level, return nonzero. */
5383 static int
5385 {
5391 else
5394 }
5396 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5397 DATA is really an int, indicating the innermost outer level of parameters.
5398 If T is a template parameter of that level or further out, return
5399 nonzero. */
5401 static int
5403 {
5409 else
5412 }
5414 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5415 parameters given by current_template_args, or reuses a
5416 previously existing one, if appropriate. Returns the DECL, or an
5417 equivalent one, if it is replaced via a call to duplicate_decls.
5419 If IS_FRIEND is true, DECL is a friend declaration. */
5421 tree
5423 {
5424 tree tmpl;
5425 tree args;
5426 tree info;
5427 tree ctx;
5431 /* True if the template is a member template, in the sense of
5432 [temp.mem]. */
5438 /* See if this is a partial specialization. */
5451 /* For a friend, we want the context of the friend, not
5452 the type of which it is a friend. */
5456 /* In the case of a virtual function, we want the class in which
5457 it is defined. */
5459 else
5460 /* Otherwise, if we're currently defining some class, the DECL
5461 is assumed to be a member of the class. */
5470 /* See if this is a primary template. */
5473 /* A friend template that specifies a class context, i.e.
5474 template <typename T> friend void A<T>::f();
5475 is not primary. */
5480 else
5484 {
5491 {
5494 }
5496 {
5498 {
5501 }
5503 {
5504 /* [temp.mem]
5506 A destructor shall not be a member template. */
5509 }
5516 {
5517 /* [basic.stc.dynamic.allocation]
5519 An allocation function can be a function
5520 template. ... Template allocation functions shall
5521 have two or more parameters. */
5524 }
5525 }
5528 {
5529 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5532 {
5538 }
5539 }
5542 /* alias-declaration */
5546 else
5547 {
5550 }
5551 }
5553 /* Check to see that the rules regarding the use of default
5554 arguments are not being violated. We check args for a friend
5555 functions when we know whether it's a definition, introducing
5556 declaration or re-declaration. */
5561 /* Ensure that there are no parameter packs in the type of this
5562 declaration that have not been expanded. */
5564 {
5565 /* Check each of the arguments individually to see if there are
5566 any bare parameter packs. */
5572 {
5575 {
5576 /* This is a PARM_DECL that contains unexpanded parameter
5577 packs. We have already complained about this in the
5578 check_for_bare_parameter_packs call, so just replace
5579 these types with ERROR_MARK_NODE. */
5582 }
5586 }
5588 /* Check for bare parameter packs in the return type and the
5589 exception specifiers. */
5591 /* Errors were already issued, set return type to int
5592 as the frontend doesn't expect error_mark_node as
5593 the return type. */
5597 }
5602 {
5605 }
5618 {
5623 /* If DECL is a TYPE_DECL for a class-template, then there won't
5624 be DECL_LANG_SPECIFIC. The information equivalent to
5625 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5629 {
5630 /* Since a template declaration already existed for this
5631 class-type, we must be redeclaring it here. Make sure
5632 that the redeclaration is valid. */
5634 current_template_parms,
5636 /* We don't need to create a new TEMPLATE_DECL; just use the
5637 one we already had. */
5639 }
5640 else
5641 {
5643 member_template_p);
5648 {
5649 /* A specialization of a member template of a template
5650 class. */
5654 }
5655 }
5656 }
5657 else
5658 {
5664 {
5667 }
5675 {
5676 tree new_tmpl;
5678 /* The declaration is a specialization of a member
5679 template, declared outside the class. Therefore, the
5680 innermost template arguments will be NULL, so we
5681 replace them with the arguments determined by the
5682 earlier call to check_explicit_specialization. */
5685 new_tmpl
5687 member_template_p);
5697 args,
5700 }
5702 /* Make sure the template headers we got make sense. */
5707 {
5712 }
5713 else
5715 {
5720 {
5724 else
5728 /* Avoid crash in import_export_decl. */
5731 }
5736 /* Can happen in erroneous input. */
5738 else
5740 }
5742 /* Check that the parms are used in the appropriate qualifying scopes
5743 in the declarator. */
5747 {
5753 /* Avoid crash in import_export_decl. */
5756 }
5757 }
5762 /* Push template declarations for global functions and types. Note
5763 that we do not try to push a global template friend declared in a
5764 template class; such a thing may well depend on the template
5765 parameters of the class. */
5768 {
5773 /* Hide template friend classes that haven't been declared yet. */
5775 {
5778 }
5779 }
5782 {
5787 /* Give template template parms a DECL_CONTEXT of the template
5788 for which they are a parameter. */
5791 {
5795 }
5801 }
5803 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5804 back to its most general template. If TMPL is a specialization,
5805 ARGS may only have the innermost set of arguments. Add the missing
5806 argument levels if necessary. */
5814 else
5815 {
5820 }
5823 && !is_friend
5826 /* Set DECL_COMDAT on template instantiations; if we force
5827 them to be emitted by explicit instantiation or -frepo,
5828 mark_needed will tell cgraph to do the right thing. */
5832 }
5834 tree
5836 {
5838 }
5840 /* FN is an inheriting constructor that inherits from the constructor
5841 template INHERITED; turn FN into a constructor template with a matching
5842 template header. */
5844 tree
5846 {
5847 tree inner_parms
5850 tree parms
5861 }
5863 /* Called when a class template TYPE is redeclared with the indicated
5864 template PARMS, e.g.:
5866 template <class T> struct S;
5867 template <class T> struct S {}; */
5869 bool
5871 {
5872 tree tmpl;
5873 tree tmpl_parms;
5877 {
5880 }
5884 /* The type is nested in some template class. Nothing to worry
5885 about here; there are no new template parameters for the nested
5886 type. */
5890 {
5892 tmpl);
5894 }
5900 {
5910 }
5913 {
5914 tree tmpl_parm;
5915 tree parm;
5916 tree tmpl_default;
5917 tree parm_default;
5931 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5932 TEMPLATE_DECL. */
5942 {
5946 }
5949 {
5950 /* We have in [temp.param]:
5952 A template-parameter may not be given default arguments
5953 by two different declarations in the same scope. */
5958 }
5961 /* Update the previous template parameters (which are the ones
5962 that will really count) with the new default value. */
5965 /* Update the new parameters, too; they'll be used as the
5966 parameters for any members. */
5969 /* Give each template template parm in this redeclaration a
5970 DECL_CONTEXT of the template for which they are a parameter. */
5972 {
5975 }
5979 }
5981 // Cannot redeclare a class template with a different set of constraints.
5983 {
5988 }
5991 }
5993 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5994 to be used when the caller has already checked
5995 (processing_template_decl
5996 && !instantiation_dependent_expression_p (expr)
5997 && potential_constant_expression (expr))
5998 and cleared processing_template_decl. */
6000 tree
6002 {
6005 complain,
6009 }
6011 /* Simplify EXPR if it is a non-dependent expression. Returns the
6012 (possibly simplified) expression. */
6014 tree
6016 {
6020 /* If we're in a template, but EXPR isn't value dependent, simplify
6021 it. We're supposed to treat:
6023 template <typename T> void f(T[1 + 1]);
6024 template <typename T> void f(T[2]);
6026 as two declarations of the same function, for example. */
6029 {
6030 processing_template_decl_sentinel s;
6032 }
6034 }
6036 tree
6038 {
6040 }
6042 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
6043 an uninstantiated expression. */
6045 tree
6047 {
6051 {
6054 else
6055 {
6056 processing_template_decl_sentinel s;
6058 }
6059 }
6061 }
6063 /* True iff T is a specialization of a variable template. */
6065 bool
6067 {
6072 }
6074 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
6075 template declaration, or a TYPE_DECL for an alias declaration. */
6077 bool
6079 {
6087 }
6089 /* Return TRUE iff T is a specialization of an alias template. */
6091 bool
6093 {
6094 /* It's an alias template specialization if it's an alias and its
6095 TYPE_NAME is a specialization of a primary template. */
6101 }
6103 /* An alias template is complex from a SFINAE perspective if a template-id
6104 using that alias can be ill-formed when the expansion is not, as with
6105 the void_t template. We determine this by checking whether the
6106 expansion for the alias template uses all its template parameters. */
6108 struct uses_all_template_parms_data
6109 {
6112 };
6114 static int
6116 {
6124 }
6126 static bool
6128 {
6143 }
6145 /* Return TRUE iff T is a specialization of a complex alias template with
6146 dependent template-arguments. */
6148 bool
6150 {
6163 }
6165 /* Return the number of innermost template parameters in TMPL. */
6167 static int
6169 {
6172 }
6174 /* Return either TMPL or another template that it is equivalent to under DR
6175 1286: An alias that just changes the name of a template is equivalent to
6176 the other template. */
6178 static tree
6180 {
6183 {
6184 /* Determine if the alias is equivalent to an underlying template. */
6196 tree alias_args = INNERMOST_TEMPLATE_ARGS
6201 /* Alias is equivalent. Strip it and repeat. */
6203 }
6206 }
6208 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6209 must be a reference-to-function or a pointer-to-function type, as specified
6210 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6211 and check that the resulting function has external linkage. */
6213 static tree
6215 tsubst_flags_t complain)
6216 {
6219 linkage_kind linkage;
6234 /* [temp.arg.nontype]/1
6236 A template-argument for a non-type, non-template template-parameter
6237 shall be one of:
6238 [...]
6239 -- the address of an object or function with external [C++11: or
6240 internal] linkage. */
6243 {
6245 {
6251 else
6254 }
6256 }
6260 {
6262 {
6267 else
6271 }
6273 }
6275 accept:
6277 {
6280 else
6282 }
6287 }
6289 /* Subroutine of convert_nontype_argument.
6290 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6291 Emit an error otherwise. */
6293 static bool
6295 tsubst_flags_t complain)
6296 {
6313 {
6318 else
6320 }
6322 }
6324 /* Returns TRUE iff the address of OP is value-dependent.
6326 14.6.2.4 [temp.dep.temp]:
6327 A non-integral non-type template-argument is dependent if its type is
6328 dependent or it has either of the following forms
6329 qualified-id
6330 & qualified-id
6331 and contains a nested-name-specifier which specifies a class-name that
6332 names a dependent type.
6334 We generalize this to just say that the address of a member of a
6335 dependent class is value-dependent; the above doesn't cover the
6336 address of a static data member named with an unqualified-id. */
6338 static bool
6340 {
6341 /* We could use get_inner_reference here, but there's no need;
6342 this is only relevant for template non-type arguments, which
6343 can only be expressed as &id-expression. */
6345 {
6349 }
6352 }
6354 /* The next set of functions are used for providing helpful explanatory
6355 diagnostics for failed overload resolution. Their messages should be
6356 indented by two spaces for consistency with the messages in
6357 call.c */
6359 static int
6361 {
6363 }
6365 /* Other failure functions should call this one, to provide a single function
6366 for setting a breakpoint on. */
6368 static int
6370 {
6372 }
6374 static int
6376 {
6381 }
6383 static int
6385 {
6391 }
6393 static int
6395 {
6399 }
6401 static int
6403 {
6406 " template parameter %qD is not a parameter pack, but "
6410 }
6412 static int
6414 {
6417 " template argument %qE does not match "
6421 }
6423 static int
6425 {
6429 }
6431 static int
6433 {
6439 }
6441 static int
6443 {
6445 {
6450 else
6452 " deduced conflicting values for non-type parameter "
6454 }
6456 }
6458 static int
6460 {
6463 " variable-sized array type %qT is not "
6465 arg);
6467 }
6469 static int
6471 {
6475 arg);
6477 }
6479 static int
6481 {
6483 {
6489 else
6494 }
6496 }
6498 static int
6500 {
6502 }
6504 static int
6507 {
6509 }
6511 static int
6514 {
6520 }
6522 static int
6525 {
6528 {
6536 }
6538 }
6540 static int
6542 {
6545 " template parameters of a template template argument are "
6548 }
6550 static int
6552 {
6558 }
6560 static int
6562 {
6567 }
6569 /* Attempt to convert the non-type template parameter EXPR to the
6570 indicated TYPE. If the conversion is successful, return the
6571 converted value. If the conversion is unsuccessful, return
6572 NULL_TREE if we issued an error message, or error_mark_node if we
6573 did not. We issue error messages for out-and-out bad template
6574 parameters, but not simply because the conversion failed, since we
6575 might be just trying to do argument deduction. Both TYPE and EXPR
6576 must be non-dependent.
6578 The conversion follows the special rules described in
6579 [temp.arg.nontype], and it is much more strict than an implicit
6580 conversion.
6582 This function is called twice for each template argument (see
6583 lookup_template_class for a more accurate description of this
6584 problem). This means that we need to handle expressions which
6585 are not valid in a C++ source, but can be created from the
6586 first call (for instance, casts to perform conversions). These
6587 hacks can go away after we fix the double coercion problem. */
6589 static tree
6591 {
6592 tree expr_type;
6596 /* Detect immediately string literals as invalid non-type argument.
6597 This special-case is not needed for correctness (we would easily
6598 catch this later), but only to provide better diagnostic for this
6599 common user mistake. As suggested by DR 100, we do not mention
6600 linkage issues in the diagnostic as this is not the point. */
6601 /* FIXME we're making this OK. */
6603 {
6609 }
6611 /* Add the ADDR_EXPR now for the benefit of
6612 value_dependent_expression_p. */
6615 {
6619 }
6621 /* If we are in a template, EXPR may be non-dependent, but still
6622 have a syntactic, rather than semantic, form. For example, EXPR
6623 might be a SCOPE_REF, rather than the VAR_DECL to which the
6624 SCOPE_REF refers. Preserving the qualifying scope is necessary
6625 so that access checking can be performed when the template is
6626 instantiated -- but here we need the resolved form so that we can
6627 convert the argument. */
6639 /* If the argument is non-dependent, perform any conversions in
6640 non-dependent context as well. */
6648 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6649 to a non-type argument of "nullptr". */
6653 /* In C++11, integral or enumeration non-type template arguments can be
6654 arbitrary constant expressions. Pointer and pointer to
6655 member arguments can be general constant expressions that evaluate
6656 to a null value, but otherwise still need to be of a specific form. */
6658 {
6660 /* A PTRMEM_CST is already constant, and a valid template
6661 argument for a parameter of pointer to member type, we just want
6662 to leave it in that form rather than lower it to a
6666 {
6667 /* C++17: A template-argument for a non-type template-parameter shall
6668 be a converted constant expression (8.20) of the type of the
6669 template-parameter. */
6675 }
6677 {
6682 }
6683 }
6687 else
6690 /* HACK: Due to double coercion, we can get a
6691 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6692 which is the tree that we built on the first call (see
6693 below when coercing to reference to object or to reference to
6694 function). We just strip everything and get to the arg.
6695 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6696 for examples. */
6698 {
6704 {
6705 /* ??? Maybe we could use convert_from_reference here, but we
6706 would need to relax its constraints because the NOP_EXPR
6707 could actually change the type to something more cv-qualified,
6708 and this is not folded by convert_from_reference. */
6713 && (same_type_ignoring_top_level_qualifiers_p
6716 {
6719 }
6720 }
6721 }
6723 /* [temp.arg.nontype]/5, bullet 1
6725 For a non-type template-parameter of integral or enumeration type,
6726 integral promotions (_conv.prom_) and integral conversions
6727 (_conv.integral_) are applied. */
6729 {
6731 {
6736 }
6741 /* Notice that there are constant expressions like '4 % 0' which
6742 do not fold into integer constants. */
6745 {
6747 {
6751 else
6757 /* else cxx_constant_value complained but gave us
6758 a real constant, so go ahead. */
6760 {
6761 /* Some assemble time constant expressions like
6762 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
6763 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
6764 as we can emit them into .rodata initializers of
6765 variables, yet they can't fold into an INTEGER_CST at
6766 compile time. Refuse them here. */
6771 }
6772 }
6773 else
6775 }
6777 /* Avoid typedef problems. */
6780 }
6781 /* [temp.arg.nontype]/5, bullet 2
6783 For a non-type template-parameter of type pointer to object,
6784 qualification conversions (_conv.qual_) and the array-to-pointer
6785 conversion (_conv.array_) are applied. */
6787 {
6790 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
6791 decay_conversion or an explicit cast. If it's a problematic cast,
6792 we'll complain about it below. */
6794 {
6799 {
6802 }
6803 }
6805 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6807 A template-argument for a non-type, non-template template-parameter
6808 shall be one of: [...]
6810 -- the name of a non-type template-parameter;
6811 -- the address of an object or function with external linkage, [...]
6812 expressed as "& id-expression" where the & is optional if the name
6813 refers to a function or array, or if the corresponding
6814 template-parameter is a reference.
6816 Here, we do not care about functions, as they are invalid anyway
6817 for a parameter of type pointer-to-object. */
6820 /* Non-type template parameters are OK. */
6821 ;
6825 {
6827 {
6830 "because %qD is a variable, not the address of "
6833 }
6835 {
6841 }
6842 /* Other values, like integer constants, might be valid
6843 non-type arguments of some other type. */
6845 }
6846 else
6847 {
6851 {
6856 }
6858 {
6864 }
6867 {
6872 }
6873 /* C++17: For a non-type template-parameter of reference or pointer
6874 type, the value of the constant expression shall not refer to (or
6875 for a pointer type, shall not be the address of):
6876 * a subobject (4.5),
6877 * a temporary object (15.2),
6878 * a string literal (5.13.5),
6879 * the result of a typeid expression (8.2.8), or
6880 * a predefined __func__ variable (11.4.1). */
6882 {
6885 decl);
6887 }
6891 {
6896 }
6898 {
6902 decl);
6904 }
6905 }
6912 }
6913 /* [temp.arg.nontype]/5, bullet 3
6915 For a non-type template-parameter of type reference to object, no
6916 conversions apply. The type referred to by the reference may be more
6917 cv-qualified than the (otherwise identical) type of the
6918 template-argument. The template-parameter is bound directly to the
6919 template-argument, which must be an lvalue. */
6921 {
6923 expr_type))
6927 {
6932 }
6935 {
6940 }
6942 /* [temp.arg.nontype]/1
6944 A template-argument for a non-type, non-template template-parameter
6945 shall be one of: [...]
6947 -- the address of an object or function with external linkage. */
6950 {
6953 {
6956 "because a reference variable does not have a constant "
6959 }
6960 }
6964 /* OK, dependent reference. We don't want to ask whether a DECL is
6966 else
6967 {
6969 {
6975 }
6977 /* DR 1155 allows internal linkage in C++11 and up. */
6980 {
6986 }
6989 }
6993 }
6994 /* [temp.arg.nontype]/5, bullet 4
6996 For a non-type template-parameter of type pointer to function, only
6997 the function-to-pointer conversion (_conv.func_) is applied. If the
6998 template-argument represents a set of overloaded functions (or a
6999 pointer to such), the matching function is selected from the set
7000 (_over.over_). */
7002 {
7003 /* If the argument is a template-id, we might not have enough
7004 context information to decay the pointer. */
7006 {
7010 }
7013 /* Null pointer values are OK in C++11. */
7019 }
7020 /* [temp.arg.nontype]/5, bullet 5
7022 For a non-type template-parameter of type reference to function, no
7023 conversions apply. If the template-argument represents a set of
7024 overloaded functions, the matching function is selected from the set
7025 (_over.over_). */
7027 {
7029 {
7031 {
7036 }
7038 }
7043 }
7044 /* [temp.arg.nontype]/5, bullet 6
7046 For a non-type template-parameter of type pointer to member function,
7047 no conversions apply. If the template-argument represents a set of
7048 overloaded member functions, the matching member function is selected
7049 from the set (_over.over_). */
7051 {
7056 /* [temp.arg.nontype] bullet 1 says the pointer to member
7057 expression must be a pointer-to-member constant. */
7062 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
7063 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
7066 }
7067 /* [temp.arg.nontype]/5, bullet 7
7069 For a non-type template-parameter of type pointer to data member,
7070 qualification conversions (_conv.qual_) are applied. */
7072 {
7073 /* [temp.arg.nontype] bullet 1 says the pointer to member
7074 expression must be a pointer-to-member constant. */
7082 }
7084 {
7086 {
7091 }
7093 }
7094 /* A template non-type parameter must be one of the above. */
7095 else
7098 /* Sanity check: did we actually convert the argument to the
7099 right type? */
7103 }
7105 /* Subroutine of coerce_template_template_parms, which returns 1 if
7106 PARM_PARM and ARG_PARM match using the rule for the template
7107 parameters of template template parameters. Both PARM and ARG are
7108 template parameters; the rest of the arguments are the same as for
7109 coerce_template_template_parms.
7110 */
7111 static int
7113 tree arg,
7114 tsubst_flags_t complain,
7115 tree in_decl,
7116 tree outer_args)
7117 {
7126 {
7128 /* We encounter instantiations of templates like
7129 template <template <template <class> class> class TT>
7130 class C; */
7131 {
7138 }
7139 /* Fall through. */
7144 /* Argument is a parameter pack but parameter is not. */
7149 /* The tsubst call is used to handle cases such as
7151 template <int> class C {};
7152 template <class T, template <T> class TT> class D {};
7153 D<int, C> d;
7155 i.e. the parameter list of TT depends on earlier parameters. */
7157 {
7162 }
7166 /* Argument is a parameter pack but parameter is not. */
7173 }
7176 }
7178 /* Coerce template argument list ARGLIST for use with template
7179 template-parameter TEMPL. */
7181 static tree
7183 tsubst_flags_t complain)
7184 {
7185 /* Consider an example where a template template parameter declared as
7187 template <class T, class U = std::allocator<T> > class TT
7189 The template parameter level of T and U are one level larger than
7190 of TT. To proper process the default argument of U, say when an
7191 instantiation `TT<int>' is seen, we need to build the full
7192 arguments containing {int} as the innermost level. Outer levels,
7193 available when not appearing as default template argument, can be
7194 obtained from the arguments of the enclosing template.
7196 Suppose that TT is later substituted with std::vector. The above
7197 instantiation is `TT<int, std::allocator<T> >' with TT at
7198 level 1, and T at level 2, while the template arguments at level 1
7199 becomes {std::vector} and the inner level 2 is {int}. */
7203 {
7205 /* We want arguments for the partial specialization, not arguments for
7206 the primary template. */
7208 else
7210 }
7212 {
7213 /* This is an argument of the current template, so we haven't set
7214 DECL_CONTEXT yet. */
7215 tree relevant_template_parms;
7217 /* Parameter levels that are greater than the level of the given
7218 template template parm are irrelevant. */
7225 }
7232 complain,
7235 }
7237 /* A cache of template template parameters with match-all default
7238 arguments. */
7240 static void
7242 {
7246 }
7247 static tree
7249 {
7254 }
7256 /* T is a bound template template-parameter. Copy its arguments into default
7257 arguments of the template template-parameter's template parameters. */
7259 static tree
7261 {
7284 {
7287 {
7290 }
7291 }
7295 }
7297 /* ARG is a bound potential template template-argument, and PARGS is a list
7298 of arguments for the corresponding template template-parameter. Adjust
7299 PARGS as appropriate for application to ARG's template, and if ARG is a
7300 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7301 arguments to the template template parameter. */
7303 static tree
7305 {
7309 {
7310 /* When comparing two template template-parameters in partial ordering,
7311 rewrite the one currently being used as an argument to have default
7312 arguments for all parameters. */
7318 }
7319 else
7320 {
7321 tree aparms
7326 }
7329 }
7331 /* Subroutine of unify for the case when PARM is a
7332 BOUND_TEMPLATE_TEMPLATE_PARM. */
7334 static int
7337 {
7341 /* The template template parm might be variadic and the argument
7342 not, so flatten both argument lists. */
7347 {
7348 /* In keeping with P0522R0, adjust P's template arguments
7349 to apply to A's template; then flatten it again. */
7358 /* If the P0522 adjustment eliminated a pack expansion, deduce
7359 empty packs. */
7365 }
7366 else
7367 {
7368 /* Deduce arguments T, i from TT<T> or TT<i>.
7369 We check each element of PARMVEC and ARGVEC individually
7370 rather than the whole TREE_VEC since they can have
7371 different number of elements, which is allowed under N2555. */
7375 /* Check if the parameters end in a pack, making them
7376 variadic. */
7383 /* If the template argument list of P contains a pack
7384 expansion that is not the last template argument, the
7385 entire template argument list is a non-deduced
7386 context. */
7404 DEDUCE_EXACT,
7407 }
7410 }
7412 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7413 template template parameters. Both PARM_PARMS and ARG_PARMS are
7414 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7415 or PARM_DECL.
7417 Consider the example:
7418 template <class T> class A;
7419 template<template <class U> class TT> class B;
7421 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7422 the parameters to A, and OUTER_ARGS contains A. */
7424 static int
7426 tree arg_parms,
7427 tsubst_flags_t complain,
7428 tree in_decl,
7429 tree outer_args)
7430 {
7442 {
7443 /* P0522R0: A template template-parameter P is at least as specialized as
7444 a template template-argument A if, given the following rewrite to two
7445 function templates, the function template corresponding to P is at
7446 least as specialized as the function template corresponding to A
7447 according to the partial ordering rules for function templates
7448 ([temp.func.order]). Given an invented class template X with the
7449 template parameter list of A (including default arguments):
7451 * Each of the two function templates has the same template parameters,
7452 respectively, as P or A.
7454 * Each function template has a single function parameter whose type is
7455 a specialization of X with template arguments corresponding to the
7456 template parameters from the respective function template where, for
7457 each template parameter PP in the template parameter list of the
7458 function template, a corresponding template argument AA is formed. If
7459 PP declares a parameter pack, then AA is the pack expansion
7460 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7462 If the rewrite produces an invalid type, then P is not at least as
7463 specialized as A. */
7465 /* So coerce P's args to apply to A's parms, and then deduce between A's
7466 args and the converted args. If that succeeds, A is at least as
7467 specialized as P, so they match.*/
7474 {
7480 }
7481 }
7483 /* Determine whether we have a parameter pack at the end of the
7484 template template parameter's template parameter list. */
7486 {
7493 {
7507 }
7508 }
7514 /* Check all of the template parameters except the parameter pack at
7515 the end (if any). */
7517 {
7526 outer_args))
7529 }
7532 {
7533 /* Check each of the template parameters in the template
7534 argument against the template parameter pack at the end of
7535 the template template parameter. */
7542 {
7549 outer_args))
7551 }
7552 }
7555 }
7557 /* Verifies that the deduced template arguments (in TARGS) for the
7558 template template parameters (in TPARMS) represent valid bindings,
7559 by comparing the template parameter list of each template argument
7560 to the template parameter list of its corresponding template
7561 template parameter, in accordance with DR150. This
7562 routine can only be called after all template arguments have been
7563 deduced. It will return TRUE if all of the template template
7564 parameter bindings are okay, FALSE otherwise. */
7565 bool
7567 {
7571 /* We're dealing with template parms in this process. */
7577 {
7582 {
7587 {
7588 /* Look inside the argument pack. */
7591 }
7594 {
7598 /* Extract the next argument from the argument
7599 pack. */
7603 /* Look at the pattern of the pack expansion. */
7606 /* Extract the template parameters from the template
7607 argument. */
7613 /* Verify that we can coerce the template template
7614 parameters from the template argument to the template
7615 parameter. This requires an exact match. */
7617 && !coerce_template_template_parms
7619 targ_parms,
7620 tf_none,
7621 tparm,
7622 targs))
7623 {
7626 }
7627 }
7628 }
7629 }
7631 out:
7635 }
7637 /* Since type attributes aren't mangled, we need to strip them from
7638 template type arguments. */
7640 static tree
7642 {
7652 }
7654 /* And from inside dependent non-type arguments like sizeof(Type). */
7656 static tree
7658 {
7668 }
7670 // A template declaration can be substituted for a constrained
7671 // template template parameter only when the argument is more
7672 // constrained than the parameter.
7673 static bool
7675 {
7678 /* For now, allow constrained template template arguments
7679 and unconstrained template template parameters. */
7685 // If the template parameter is constrained, we need to rewrite its
7686 // constraints in terms of the ARG's template parameters. This ensures
7687 // that all of the template parameter types will have the same depth.
7688 //
7689 // Note that this is only valid when coerce_template_template_parm is
7690 // true for the innermost template parameters of PARM and ARG. In other
7691 // words, because coercion is successful, this conversion will be valid.
7693 {
7700 }
7703 }
7705 // Convert a placeholder argument into a binding to the original
7706 // parameter. The original parameter is saved as the TREE_TYPE of
7707 // ARG.
7710 {
7713 }
7715 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
7716 because one of them is dependent. But we need to represent the
7717 conversion for the benefit of cp_tree_equal. */
7719 static tree
7721 {
7722 /* Auto parms get no conversion. */
7725 /* We don't need or want to add this conversion now if we're going to use the
7726 argument for deduction. */
7738 }
7740 /* Convert the indicated template ARG as necessary to match the
7741 indicated template PARM. Returns the converted ARG, or
7742 error_mark_node if the conversion was unsuccessful. Error and
7743 warning messages are issued under control of COMPLAIN. This
7744 conversion is for the Ith parameter in the parameter list. ARGS is
7745 the full set of template arguments deduced so far. */
7747 static tree
7749 tree arg,
7750 tree args,
7751 tsubst_flags_t complain,
7753 tree in_decl)
7754 {
7755 tree orig_arg;
7756 tree val;
7762 /* Trivially convert placeholders. */
7771 {
7772 /* The template argument was the name of some
7773 member function. That's usually
7774 invalid, but static members are OK. In any
7775 case, grab the underlying fields/functions
7776 and issue an error later if required. */
7779 }
7787 /* When determining whether an argument pack expansion is a template,
7788 look at the pattern. */
7792 /* Deal with an injected-class-name used as a template template arg. */
7794 {
7797 {
7807 }
7808 }
7810 is_tmpl_type =
7826 {
7828 {
7832 }
7835 "to refer to a type member of a template parameter, "
7840 typename_type,
7841 complain);
7844 }
7846 {
7848 {
7850 {
7862 else
7865 }
7866 }
7868 }
7870 {
7872 {
7879 else
7882 }
7884 }
7887 /* We already did the appropriate conversion when packing args. */
7890 {
7892 {
7894 /* The number of argument required is not known yet.
7895 Just accept it for now. */
7897 else
7898 {
7900 tree argparm;
7902 /* Strip alias templates that are equivalent to another
7903 template. */
7909 args))
7910 {
7913 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7914 TEMPLATE_DECL. */
7916 {
7921 }
7922 }
7923 else
7924 {
7926 {
7933 }
7936 }
7938 // Check that the constraints are compatible before allowing the
7939 // substitution.
7942 {
7944 {
7950 }
7952 }
7953 }
7954 }
7955 else
7957 /* We only form one instance of each template specialization.
7958 Therefore, if we use a non-canonical variant (i.e., a
7959 typedef), any future messages referring to the type will use
7960 the typedef, which is confusing if those future uses do not
7961 themselves also use the typedef. */
7964 }
7965 else
7966 {
7971 /* We don't have enough levels of args to do any substitution. This
7974 {
7978 }
7979 else
7987 /* We used to call digest_init here. However, digest_init
7988 will report errors, which we don't want when complain
7989 is zero. More importantly, digest_init will try too
7990 hard to convert things: for example, `0' should not be
7991 converted to pointer type at this point according to
7992 the standard. Accepting this is not merely an
7993 extension, since deciding whether or not these
7994 conversions can occur is part of determining which
7995 function template to call, or whether a given explicit
7996 argument specification is valid. */
7998 else
7999 {
8002 }
8012 {
8013 /* Reject template arguments that are references to built-in
8014 functions with no library fallbacks. */
8023 }
8026 {
8027 /* Strip typedefs from the SCOPE_REF. */
8030 complain);
8033 }
8034 }
8037 }
8039 /* Coerces the remaining template arguments in INNER_ARGS (from
8040 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
8041 Returns the coerced argument pack. PARM_IDX is the position of this
8042 parameter in the template parameter list. ARGS is the original
8043 template argument list. */
8044 static tree
8047 tree args,
8048 tree inner_args,
8050 tree new_args,
8052 tree in_decl,
8053 tsubst_flags_t complain)
8054 {
8057 tree packed_args;
8058 tree argument_pack;
8065 {
8066 /* When the template parameter is a non-type template parameter pack
8067 or template template parameter pack whose type or template
8068 parameters use parameter packs, we know exactly how many arguments
8069 we are looking for. Build a vector of the instantiated decls for
8070 these template parameters in PACKED_PARMS. */
8071 /* We can't use make_pack_expansion here because it would interpret a
8072 _DECL as a use rather than a declaration. */
8086 /* If we're doing a partial instantiation of a member template,
8087 verify that all of the types used for the non-type
8088 template parameter pack are, in fact, valid for non-type
8089 template parameters. */
8092 {
8095 {
8099 }
8100 /* We don't know how many args we have yet, just
8101 use the unconverted ones for now. */
8103 }
8106 }
8107 /* Check if we have a placeholder pack, which indicates we're
8108 in the context of a introduction list. In that case we want
8109 to match this pack to the single placeholder. */
8113 {
8116 }
8117 else
8120 /* Convert the remaining arguments, which will be a part of the
8121 parameter pack "parm". */
8124 {
8130 {
8131 /* Once we've packed as many args as we have types, stop. */
8135 /* We don't know how many args we have yet, just
8136 use the unconverted ones for now. */
8138 else
8140 }
8143 {
8146 }
8147 else
8150 in_decl);
8154 }
8158 {
8163 }
8168 else
8169 {
8172 }
8179 }
8181 /* Returns the number of pack expansions in the template argument vector
8182 ARGS. */
8184 static int
8186 {
8191 {
8195 }
8197 }
8199 /* Convert all template arguments to their appropriate types, and
8200 return a vector containing the innermost resulting template
8201 arguments. If any error occurs, return error_mark_node. Error and
8202 warning messages are issued under control of COMPLAIN.
8204 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8205 for arguments not specified in ARGS. Otherwise, if
8206 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
8207 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
8208 USE_DEFAULT_ARGS is false, then all arguments must be specified in
8209 ARGS. */
8211 static tree
8213 tree args,
8214 tree in_decl,
8215 tsubst_flags_t complain,
8218 {
8220 tree orig_inner_args;
8221 tree inner_args;
8222 tree new_args;
8223 tree new_inner_args;
8227 /* When used as a boolean value, indicates whether this is a
8228 variadic template parameter list. Since it's an int, we can also
8229 subtract it from nparms to get the number of non-variadic
8230 parameters. */
8235 /* Adjustment to nparms for fixed parameter packs. */
8240 /* Likewise for parameters with default arguments. */
8248 /* Determine if there are any parameter packs or default arguments. */
8250 {
8258 }
8261 /* If there are no parameters that follow a parameter pack, we need to
8262 expand any argument packs so that we can deduce a parameter pack from
8263 some non-packed args followed by an argument pack, as in variadic85.C.
8264 If there are such parameters, we need to leave argument packs intact
8265 so the arguments are assigned properly. This can happen when dealing
8266 with a nested class inside a partial specialization of a class
8267 template, as in variadic92.C, or when deducing a template parameter pack
8268 from a sub-declarator, as in variadic114.C. */
8272 /* Count any pack expansion args. */
8278 && require_all_args
8279 && !variadic_args_p
8280 && (!use_default_args
8283 {
8284 bad_nargs:
8286 {
8288 {
8292 }
8293 else
8300 }
8303 }
8304 /* We can't pass a pack expansion to a non-pack parameter of an alias
8305 template (DR 1430). */
8309 && variadic_args_p
8311 {
8313 {
8315 {
8321 {
8324 "pack expansion argument for non-pack parameter "
8326 else
8328 "pack expansion argument for non-pack parameter "
8332 }
8333 }
8335 found:;
8336 }
8338 }
8340 /* We need to evaluate the template arguments, even though this
8341 template-id may be nested within a "sizeof". */
8350 {
8351 tree arg;
8352 tree parm;
8354 /* Get the Ith template parameter. */
8358 {
8361 }
8363 /* Calculate the next argument. */
8366 else
8371 {
8372 /* Some arguments will be placed in the
8373 template parameter pack PARM. */
8380 {
8381 /* We don't know how many args we have yet, just use the
8382 unconverted (and still packed) ones for now. */
8386 }
8390 /* Store this argument. */
8392 {
8393 lost++;
8394 /* We are done with all of the arguments. */
8397 }
8398 else
8399 {
8403 {
8406 }
8407 }
8410 }
8412 {
8414 {
8415 /* "If every valid specialization of a variadic template
8416 requires an empty template parameter pack, the template is
8417 ill-formed, no diagnostic required." So check that the
8418 pattern works with this parameter. */
8423 in_decl);
8425 {
8430 }
8432 /* Recover from missing typename. */
8436 /* We don't know how many args we have yet, just
8437 use the unconverted ones for now. */
8441 }
8442 }
8444 {
8445 /* There must be a default arg in this case. */
8448 /* The position of the first default template argument,
8449 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8450 Record that. */
8454 }
8455 else
8459 {
8462 }
8464 {
8465 /* This can occur if there was an error in the template
8466 parameter list itself (which we would already have
8467 reported) that we are trying to recover from, e.g., a class
8468 template with a parameter list such as
8469 template<typename..., typename> (cpp0x/variadic150.C). */
8472 /* This can also happen with a fixed parameter pack (71834). */
8475 }
8476 else
8482 lost++;
8484 }
8489 {
8490 /* If we had fixed parameter packs, we didn't know how many arguments we
8491 actually needed earlier; now we do. */
8495 }
8498 {
8499 /* We had some pack expansion arguments that will only work if the packs
8500 are empty, but wait until instantiation time to complain.
8501 See variadic-ttp3.C. */
8511 }
8514 {
8517 }
8524 }
8526 /* Convert all template arguments to their appropriate types, and
8527 return a vector containing the innermost resulting template
8528 arguments. If any error occurs, return error_mark_node. Error and
8529 warning messages are not issued.
8531 Note that no function argument deduction is performed, and default
8532 arguments are used to fill in unspecified arguments. */
8533 tree
8535 {
8537 }
8539 /* Convert all template arguments to their appropriate type, and
8540 instantiate default arguments as needed. This returns a vector
8541 containing the innermost resulting template arguments, or
8542 error_mark_node if unsuccessful. */
8543 tree
8545 tsubst_flags_t complain)
8546 {
8548 }
8550 /* Like coerce_template_parms. If PARMS represents all template
8551 parameters levels, this function returns a vector of vectors
8552 representing all the resulting argument levels. Note that in this
8553 case, only the innermost arguments are coerced because the
8554 outermost ones are supposed to have been coerced already.
8556 Otherwise, if PARMS represents only (the innermost) vector of
8557 parameters, this function returns a vector containing just the
8558 innermost resulting arguments. */
8560 static tree
8562 tree args,
8563 tree in_decl,
8564 tsubst_flags_t complain,
8567 {
8570 tree coerced_args;
8573 {
8575 tree level;
8581 {
8582 tree l;
8586 require_all_args,
8587 use_default_args);
8588 else
8595 }
8596 }
8597 else
8600 require_all_args,
8601 use_default_args);
8603 }
8605 /* Returns 1 if template args OT and NT are equivalent. */
8607 int
8609 {
8618 /* For member templates */
8627 {
8644 }
8648 {
8651 /* Don't treat an alias template specialization with dependent
8652 arguments as equivalent to its underlying type when used as a
8653 template argument; we need them to be distinct so that we
8654 substitute into the specialization arguments at instantiation
8655 time. And aliases can't be equivalent without being ==, so
8656 we don't need to look any deeper.
8658 During partial ordering, however, we need to treat them normally so
8659 that we can order uses of the same alias with different
8660 cv-qualification (79960). */
8664 else
8666 }
8669 else
8670 {
8671 /* Try to treat a template non-type argument that has been converted
8672 to the parameter type as equivalent to one that hasn't yet. */
8685 }
8686 }
8688 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8689 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8690 NEWARG_PTR with the offending arguments if they are non-NULL. */
8692 int
8696 {
8709 {
8714 {
8720 }
8721 }
8723 }
8727 {
8729 }
8731 /* Implement a freelist interface for objects of type T.
8733 Head is a separate object, rather than a regular member, so that we
8734 can define it as a GTY deletable pointer, which is highly
8735 desirable. A data member could be declared that way, but then the
8736 containing object would implicitly get GTY((user)), which would
8737 prevent us from instantiating freelists as global objects.
8738 Although this way we can create freelist global objects, they're
8739 such thin wrappers that instantiating temporaries at every use
8740 loses nothing and saves permanent storage for the freelist object.
8742 Member functions next, anew, poison and reinit have default
8743 implementations that work for most of the types we're interested
8744 in, but if they don't work for some type, they should be explicitly
8745 specialized. See the comments before them for requirements, and
8746 the example specializations for the tree_list_freelist. */
8748 class freelist
8749 {
8750 /* Return the next object in a chain. We could just do type
8751 punning, but if we access the object with its underlying type, we
8752 avoid strict-aliasing trouble. This needs only work between
8753 poison and reinit. */
8756 /* Return a newly allocated, uninitialized or minimally-initialized
8757 object of type T. Any initialization performed by anew should
8758 either remain across the life of the object and the execution of
8759 poison, or be redone by reinit. */
8762 /* Optionally scribble all over the bits holding the object, so that
8763 they become (mostly?) uninitialized memory. This is called while
8764 preparing to make the object part of the free list. */
8769 #ifdef ENABLE_GC_CHECKING
8770 /* Poison the data, to indicate the data is garbage. */
8773 #endif
8774 /* Let valgrind know the object is free. */
8777 /* Let valgrind know the next portion of the object is available,
8778 but uninitialized. */
8780 }
8782 /* Bring an object that underwent at least one lifecycle after anew
8783 and before the most recent free and poison, back to a usable
8784 state, reinitializing whatever is needed for it to be
8785 functionally equivalent to an object just allocated and returned
8786 by anew. This may poison or clear the next field, used by
8787 freelist housekeeping after poison was called. */
8791 #ifdef ENABLE_GC_CHECKING
8793 #endif
8794 /* Let valgrind know the entire object is available, but
8795 uninitialized. */
8797 }
8799 /* Reference a GTY-deletable pointer that points to the first object
8800 in the free list proper. */
8803 /* Construct a freelist object chaining objects off of HEAD. */
8806 /* Add OBJ to the free object list. The former head becomes OBJ's
8807 successor. */
8809 {
8813 }
8815 /* Take an object from the free list, if one is available, or
8816 allocate a new one. Objects taken from the free list should be
8817 regarded as filled with garbage, except for bits that are
8818 configured to be preserved across free and alloc. */
8820 {
8822 {
8827 }
8828 else
8830 }
8831 };
8833 /* Explicitly specialize the interfaces for freelist<tree_node>: we
8834 want to allocate a TREE_LIST using the usual interface, and ensure
8835 TREE_CHAIN remains functional. Alas, we have to duplicate a bit of
8836 build_tree_list logic in reinit, so this could go out of sync. */
8840 {
8842 }
8844 inline tree
8846 {
8848 }
8852 {
8858 #ifdef ENABLE_GC_CHECKING
8861 /* Poison the data, to indicate the data is garbage. */
8864 #endif
8865 /* Let valgrind know the object is free. */
8867 /* But we still want to use the TREE_CODE and TREE_CHAIN parts. */
8871 #ifdef ENABLE_GC_CHECKING
8873 /* Keep TREE_CHAIN functional. */
8875 #else
8877 #endif
8878 }
8882 {
8885 #ifdef ENABLE_GC_CHECKING
8889 #endif
8891 /* Let valgrind know the entire object is available, but
8892 uninitialized. */
8895 #ifdef ENABLE_GC_CHECKING
8897 #else
8899 #endif
8900 }
8902 /* Point to the first object in the TREE_LIST freelist. */
8904 /* Return the/an actual TREE_LIST freelist. */
8907 {
8909 }
8911 /* Point to the first object in the tinst_level freelist. */
8913 /* Return the/an actual tinst_level freelist. */
8916 {
8918 }
8920 /* Point to the first object in the pending_template freelist. */
8922 /* Return the/an actual pending_template freelist. */
8925 {
8927 }
8929 /* Build the TREE_LIST object out of a split list, store it
8930 permanently, and return it. */
8931 tree
8933 {
8942 }
8946 /* Increment OBJ's refcount unless it is already infinite. */
8949 {
8953 }
8955 /* Release storage for OBJ and node, if it's a TREE_LIST. */
8956 void
8958 {
8962 }
8964 /* Decrement OBJ's refcount if not infinite. If it reaches zero, release
8965 OBJ's DECL and OBJ, and start over with the tinst_level object that
8966 used to be referenced by OBJ's NEXT. */
8967 static void
8969 {
8973 {
8977 }
8978 }
8980 /* Modify PTR so that it points to OBJ, adjusting the refcounts of OBJ
8981 and of the former PTR. Omitting the second argument is equivalent
8982 to passing (T*)NULL; this is allowed because passing the
8983 zero-valued integral constant NULL confuses type deduction and/or
8984 overload resolution. */
8986 static void
8988 {
8992 }
8994 static void
8996 {
9006 /* We are called both from instantiate_decl, where we've already had a
9007 tinst_level pushed, and instantiate_template, where we haven't.
9008 Compensate. */
9010 level = !current_tinst_level
9022 else
9031 }
9034 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
9035 ARGLIST. Valid choices for FNS are given in the cp-tree.def
9036 documentation for TEMPLATE_ID_EXPR. */
9038 tree
9040 {
9041 tree type;
9049 {
9052 }
9055 {
9057 unknown_type_node,
9059 arglist);
9061 }
9068 }
9070 /* Within the scope of a template class S<T>, the name S gets bound
9071 (in build_self_reference) to a TYPE_DECL for the class, not a
9072 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
9073 or one of its enclosing classes, and that type is a template,
9074 return the associated TEMPLATE_DECL. Otherwise, the original
9075 DECL is returned.
9077 Also handle the case when DECL is a TREE_LIST of ambiguous
9078 injected-class-names from different bases. */
9080 tree
9082 {
9086 /* DR 176: A lookup that finds an injected-class-name (10.2
9087 [class.member.lookup]) can result in an ambiguity in certain cases
9088 (for example, if it is found in more than one base class). If all of
9089 the injected-class-names that are found refer to specializations of
9090 the same class template, and if the name is followed by a
9091 template-argument-list, the reference refers to the class template
9092 itself and not a specialization thereof, and is not ambiguous. */
9094 {
9097 {
9103 }
9106 else
9108 }
9114 }
9116 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
9117 parameters, find the desired type.
9119 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
9121 IN_DECL, if non-NULL, is the template declaration we are trying to
9122 instantiate.
9124 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
9125 the class we are looking up.
9127 Issue error and warning messages under control of COMPLAIN.
9129 If the template class is really a local class in a template
9130 function, then the FUNCTION_CONTEXT is the function in which it is
9131 being instantiated.
9133 ??? Note that this function is currently called *twice* for each
9134 template-id: the first time from the parser, while creating the
9135 incomplete type (finish_template_type), and the second type during the
9136 real instantiation (instantiate_template_class). This is surely something
9137 that we want to avoid. It also causes some problems with argument
9138 coercion (see convert_nontype_argument for more information on this). */
9140 static tree
9143 {
9145 tree t;
9148 spec_entry elt;
9149 hashval_t hash;
9152 {
9156 else
9157 {
9164 }
9167 }
9169 {
9172 /* If we are declaring a constructor, say A<T>::A<T>, we will get
9173 an implicit typename for the second A. Deal with it. */
9178 {
9181 }
9182 }
9185 {
9188 }
9190 {
9194 }
9196 {
9199 }
9201 /* Issue an error message if we didn't find a template. */
9203 {
9207 }
9210 /* Make sure it's a user visible template, if it was named by
9211 the user. */
9214 {
9216 {
9220 }
9222 }
9226 /* An alias that just changes the name of a template is equivalent to the
9227 other template, so if any of the arguments are pack expansions, strip
9228 the alias to avoid problems with a pack expansion passed to a non-pack
9229 alias template parameter (DR 1430). */
9234 {
9235 tree parm;
9244 }
9245 else
9246 {
9248 tree gen_tmpl;
9249 tree type_decl;
9257 /* An error occurred while building the template TEMPL, and a
9258 diagnostic has most certainly been emitted for that
9259 already. Let's propagate that error. */
9268 {
9269 /* We've been given an incomplete set of template arguments.
9270 For example, given:
9272 template <class T> struct S1 {
9273 template <class U> struct S2 {};
9274 template <class U> struct S2<U*> {};
9275 };
9277 we will be called with an ARGLIST of `U*', but the
9278 TEMPLATE will be `template <class T> template
9279 <class U> struct S1<T>::S2'. We must fill in the missing
9280 arguments. */
9284 }
9286 /* Now we should have enough arguments. */
9289 /* From here on, we're only interested in the most general
9290 template. */
9292 /* Calculate the BOUND_ARGS. These will be the args that are
9293 actually tsubst'd into the definition to create the
9294 instantiation. */
9296 complain,
9301 /* We were unable to bind the arguments. */
9304 /* In the scope of a template class, explicit references to the
9305 template class refer to the type of the template, not any
9306 instantiation of it. For example, in:
9308 template <class T> class C { void f(C<T>); }
9310 the `C<T>' is just the same as `C'. Outside of the
9311 class, however, such a reference is an instantiation. */
9315 {
9320 }
9322 /* If we already have this specialization, return it. */
9332 /* If the the template's constraints are not satisfied,
9333 then we cannot form a valid type.
9335 Note that the check is deferred until after the hash
9336 lookup. This prevents redundant checks on previously
9337 instantiated specializations. */
9339 {
9341 {
9344 }
9346 }
9350 /* If the deduced arguments are invalid, then the binding
9351 failed. */
9355 complain))
9362 {
9367 }
9377 /* Create the type. */
9379 {
9380 /* The user referred to a specialization of an alias
9381 template represented by GEN_TMPL.
9383 [temp.alias]/2 says:
9385 When a template-id refers to the specialization of an
9386 alias template, it is equivalent to the associated
9387 type obtained by substitution of its
9388 template-arguments for the template-parameters in the
9389 type-id of the alias template. */
9392 /* Note that the call above (by indirectly calling
9393 register_specialization in tsubst_decl) registers the
9394 TYPE_DECL representing the specialization of the alias
9395 template. So next time someone substitutes ARGLIST for
9396 the template parms into the alias template (GEN_TMPL),
9397 she'll get that TYPE_DECL back. */
9401 }
9403 {
9405 {
9416 }
9417 else
9418 {
9419 /* We don't want to call start_enum for this type, since
9420 the values for the enumeration constants may involve
9421 template parameters. And, no one should be interested
9422 in the enumeration constants for such a type. */
9425 }
9429 }
9431 {
9432 /* Lambda closures are regenerated in tsubst_lambda_expr, not
9433 instantiated here. */
9441 /* A local class. Make sure the decl gets registered properly. */
9448 /* This instantiation is another name for the primary
9449 template type. Set the TYPE_CANONICAL field
9450 appropriately. */
9453 /* Some of the template arguments require structural
9454 equality testing, so this template class requires
9455 structural equality testing. */
9457 }
9458 else
9461 /* If we called start_enum or pushtag above, this information
9462 will already be set up. */
9464 {
9471 }
9472 else
9476 {
9482 {
9485 }
9486 }
9490 {
9494 {
9495 tree attributes
9503 }
9504 }
9506 /* Let's consider the explicit specialization of a member
9507 of a class template specialization that is implicitly instantiated,
9508 e.g.:
9509 template<class T>
9510 struct S
9511 {
9512 template<class U> struct M {}; //#0
9513 };
9515 template<>
9516 template<>
9517 struct S<int>::M<char> //#1
9518 {
9519 int i;
9520 };
9521 [temp.expl.spec]/4 says this is valid.
9523 In this case, when we write:
9524 S<int>::M<char> m;
9526 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
9527 the one of #0.
9529 When we encounter #1, we want to store the partial instantiation
9530 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
9532 For all cases other than this "explicit specialization of member of a
9533 class template", we just want to store the most general template into
9534 the CLASSTYPE_TI_TEMPLATE of M.
9536 This case of "explicit specialization of member of a class template"
9537 only happens when:
9538 1/ the enclosing class is an instantiation of, and therefore not
9539 the same as, the context of the most general template, and
9540 2/ we aren't looking at the partial instantiation itself, i.e.
9541 the innermost arguments are not the same as the innermost parms of
9542 the most general template.
9544 So it's only when 1/ and 2/ happens that we want to use the partial
9545 instantiation of the member template in lieu of its most general
9546 template. */
9550 /* the enclosing class must be an instantiation... */
9553 {
9557 tree partial_inst_args =
9564 use_partial_inst_tmpl =
9565 /*...and we must not be looking at the partial instantiation
9566 itself. */
9568 partial_inst_args);
9569 }
9572 /* This case is easy; there are no member templates involved. */
9574 else
9575 {
9576 /* This is a full instantiation of a member template. Find
9577 the partial instantiation of which this is an instance. */
9579 /* Temporarily reduce by one the number of levels in the ARGLIST
9580 so as to avoid comparing the last set of arguments. */
9584 /* FOUND is either a proper class type, or an alias
9585 template specialization. In the later case, it's a
9586 TYPE_DECL, resulting from the substituting of arguments
9587 for parameters in the TYPE_DECL of the alias template
9588 done earlier. So be careful while getting the template
9589 of FOUND. */
9591 ? found
9595 }
9597 // Build template info for the new specialization.
9606 /* Note this use of the partial instantiation so we can check it
9607 later in maybe_process_partial_specialization. */
9614 /* Now that the type has been registered on the instantiations
9615 list, we set up the enumerators. Because the enumeration
9616 constants may involve the enumeration type itself, we make
9617 sure to register the type first, and then create the
9618 constants. That way, doing tsubst_expr for the enumeration
9619 constants won't result in recursive calls here; we'll find
9620 the instantiation and exit above. */
9624 /* If the type makes use of template parameters, the
9625 code that generates debugging information will crash. */
9628 /* Possibly limit visibility based on template args. */
9635 }
9636 }
9638 /* Wrapper for lookup_template_class_1. */
9640 tree
9643 {
9644 tree ret;
9650 }
9652 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
9654 tree
9656 {
9657 /* The type of the expression is NULL_TREE since the template-id could refer
9658 to an explicit or partial specialization. */
9661 /* Except that concepts are always bool. */
9664 }
9666 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9668 tree
9670 {
9674 /* We never want to return a VAR_DECL for a variable concept, since they
9675 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
9690 {
9692 {
9695 }
9697 }
9699 /* If a template-id refers to a specialization of a variable
9700 concept, then the expression is true if and only if the
9701 concept's constraints are satisfied by the given template
9702 arguments.
9704 NOTE: This is an extension of Concepts Lite TS that
9705 allows constraints to be used in expressions. */
9707 {
9710 }
9713 }
9715 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
9716 TARGS template args, and instantiate it if it's not dependent. */
9718 tree
9720 tsubst_flags_t complain)
9721 {
9724 {
9727 }
9730 }
9732 \f
9733 struct pair_fn_data
9734 {
9735 tree_fn_t fn;
9736 tree_fn_t any_fn;
9738 /* True when we should also visit template parameters that occur in
9739 non-deduced contexts. */
9742 };
9744 /* Called from for_each_template_parm via walk_tree. */
9746 static tree
9748 {
9755 #define WALK_SUBTREE(NODE) \
9756 do \
9757 { \
9758 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
9759 pfd->include_nondeduced_p, \
9760 pfd->any_fn); \
9761 if (result) goto out; \
9762 } \
9763 while (0)
9773 {
9777 /* Fall through. */
9783 else
9793 /* Since we're not going to walk subtrees, we have to do this
9794 explicitly here. */
9796 /* Fall through. */
9799 /* Check the return type. */
9802 /* Check the parameter types. Since default arguments are not
9803 instantiated until they are needed, the TYPE_ARG_TYPES may
9804 contain expressions that involve template parameters. But,
9805 no-one should be looking at them yet. And, once they're
9806 instantiated, they don't contain template parameters, so
9807 there's no point in looking at them then, either. */
9808 {
9809 tree parm;
9814 /* Since we've already handled the TYPE_ARG_TYPES, we don't
9815 want walk_tree walking into them itself. */
9817 }
9820 {
9824 }
9843 /* Fall through. */
9855 /* Record template parameters such as `T' inside `TT<T>'. */
9857 /* Fall through. */
9869 /* A template template parameter is encountered. */
9873 /* Already substituted template template parameter */
9878 /* A template-id in a TYPENAME_TYPE might be a deduced context after
9879 partial instantiation. */
9891 /* If there's no type, then this thing must be some expression
9892 involving template parameters. */
9914 }
9916 #undef WALK_SUBTREE
9918 /* We didn't find any template parameters we liked. */
9919 out:
9921 }
9923 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9924 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9925 call FN with the parameter and the DATA.
9926 If FN returns nonzero, the iteration is terminated, and
9927 for_each_template_parm returns 1. Otherwise, the iteration
9928 continues. If FN never returns a nonzero value, the value
9929 returned by for_each_template_parm is 0. If FN is NULL, it is
9930 considered to be the function which always returns 1.
9932 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9933 parameters that occur in non-deduced contexts. When false, only
9934 visits those template parameters that can be deduced. */
9936 static tree
9940 tree_fn_t any_fn)
9941 {
9943 tree result;
9945 /* Set up. */
9951 /* Walk the tree. (Conceptually, we would like to walk without
9952 duplicates, but for_each_template_parm_r recursively calls
9953 for_each_template_parm, so we would need to reorganize a fair
9954 bit to use walk_tree_without_duplicates, so we keep our own
9955 visited list.) */
9958 else
9961 for_each_template_parm_r,
9965 /* Clean up. */
9967 {
9970 }
9973 }
9975 /* Returns true if T depends on any template parameter. */
9977 int
9979 {
10009 else
10010 {
10013 }
10018 }
10020 /* Returns true iff current_function_decl is an incompletely instantiated
10021 template. Useful instead of processing_template_decl because the latter
10022 is set to 0 during instantiate_non_dependent_expr. */
10024 bool
10026 {
10035 }
10037 /* Returns true if T depends on any template parameter with level LEVEL. */
10039 bool
10041 {
10044 }
10046 /* Returns true if the signature of DECL depends on any template parameter from
10047 its enclosing class. */
10049 bool
10051 {
10061 template_parm_outer_level,
10071 }
10073 /* Returns TRUE iff INST is an instantiation we don't need to do in an
10074 ill-formed translation unit, i.e. a variable or function that isn't
10075 usable in a constant expression. */
10079 {
10084 }
10086 /* Returns TRUE iff we should refuse to instantiate DECL because it's
10087 neglectable and instantiated from within an erroneous instantiation. */
10089 static bool
10091 {
10102 }
10110 /* We're starting to instantiate D; record the template instantiation context
10111 at LOC for diagnostics and to restore it later. */
10113 static bool
10115 {
10119 {
10120 /* Tell error.c not to try to instantiate any templates. */
10123 "template instantiation depth exceeds maximum of %d"
10125 max_tinst_depth);
10127 }
10129 /* If the current instantiation caused problems, don't let it instantiate
10130 anything else. Do allow deduction substitution and decls usable in
10131 constant expressions. */
10135 /* When not -quiet, dump template instantiations other than functions, since
10136 announce_function will take care of those. */
10157 }
10159 /* We're starting substitution of TMPL<ARGS>; record the template
10160 substitution context for diagnostics and to restore it later. */
10162 static bool
10164 {
10166 }
10168 /* We're starting to instantiate D; record INPUT_LOCATION and the
10169 template instantiation context for diagnostics and to restore it
10170 later. */
10172 bool
10174 {
10176 }
10178 /* Likewise, but record LOC as the program location. */
10180 bool
10182 {
10185 }
10187 /* We're done instantiating this template; return to the instantiation
10188 context. */
10190 void
10192 {
10193 /* Restore the filename and line number stashed away when we started
10194 this instantiation. */
10198 }
10200 /* We're instantiating a deferred template; restore the template
10201 instantiation context in which the instantiation was requested, which
10202 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
10204 static tree
10206 {
10218 }
10220 /* Returns the TINST_LEVEL which gives the original instantiation
10221 context. */
10225 {
10231 }
10233 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
10234 vector of template arguments, as for tsubst.
10236 Returns an appropriate tsubst'd friend declaration. */
10238 static tree
10240 {
10241 tree new_friend;
10246 /* This was a friend declared with an explicit template
10247 argument list, e.g.:
10249 friend void f<>(T);
10251 to indicate that f was a template instantiation, not a new
10252 function declaration. Now, we have to figure out what
10253 instantiation of what template. */
10254 {
10256 tree new_args;
10257 tree tmpl;
10260 /* Friend functions are looked up in the containing namespace scope.
10261 We must enter that scope, to avoid finding member functions of the
10262 current class with same name. */
10277 tsk_none);
10279 }
10283 /* The NEW_FRIEND will look like an instantiation, to the
10284 compiler, but is not an instantiation from the point of view of
10285 the language. For example, we might have had:
10287 template <class T> struct S {
10288 template <class U> friend void f(T, U);
10289 };
10291 Then, in S<int>, template <class U> void f(int, U) is not an
10292 instantiation of anything. */
10298 {
10302 }
10304 /* The mangled name for the NEW_FRIEND is incorrect. The function
10305 is not a template instantiation and should not be mangled like
10306 one. Therefore, we forget the mangling here; we'll recompute it
10307 later if we need it. */
10309 {
10312 }
10315 {
10316 tree old_decl;
10317 tree new_friend_template_info;
10318 tree new_friend_result_template_info;
10319 tree ns;
10322 /* We must save some information from NEW_FRIEND before calling
10323 duplicate decls since that function will free NEW_FRIEND if
10324 possible. */
10326 new_friend_is_defn =
10331 {
10332 /* This declaration is a `primary' template. */
10335 new_friend_result_template_info
10337 }
10338 else
10341 /* Inside pushdecl_namespace_level, we will push into the
10342 current namespace. However, the friend function should go
10343 into the namespace of the template. */
10353 {
10354 /* This new friend declaration matched an existing
10355 declaration. For example, given:
10357 template <class T> void f(T);
10358 template <class U> class C {
10359 template <class T> friend void f(T) {}
10360 };
10362 the friend declaration actually provides the definition
10363 of `f', once C has been instantiated for some type. So,
10364 old_decl will be the out-of-class template declaration,
10365 while new_friend is the in-class definition.
10367 But, if `f' was called before this point, the
10368 instantiation of `f' will have DECL_TI_ARGS corresponding
10369 to `T' but not to `U', references to which might appear
10370 in the definition of `f'. Previously, the most general
10371 template for an instantiation of `f' was the out-of-class
10372 version; now it is the in-class version. Therefore, we
10373 run through all specialization of `f', adding to their
10374 DECL_TI_ARGS appropriately. In particular, they need a
10375 new set of outer arguments, corresponding to the
10376 arguments for this class instantiation.
10378 The same situation can arise with something like this:
10380 friend void f(int);
10381 template <class T> class C {
10382 friend void f(T) {}
10383 };
10385 when `C<int>' is instantiated. Now, `f(int)' is defined
10386 in the class. */
10389 /* On the other hand, if the in-class declaration does
10390 *not* provide a definition, then we don't want to alter
10391 existing definitions. We can just leave everything
10392 alone. */
10393 ;
10394 else
10395 {
10399 /* Overwrite whatever template info was there before, if
10400 any, with the new template information pertaining to
10401 the declaration. */
10405 {
10406 /* We should have called reregister_specialization in
10407 duplicate_decls. */
10412 /* Instantiate it if the global has already been used. */
10416 }
10417 else
10418 {
10419 tree t;
10421 /* Indicate that the old function template is a partial
10422 instantiation. */
10430 /* Reassign any specializations already in the hash table
10431 to the new more general template, and add the
10432 additional template args. */
10436 {
10438 spec_entry elt;
10450 register_specialization
10453 }
10455 }
10456 }
10458 /* The information from NEW_FRIEND has been merged into OLD_DECL
10459 by duplicate_decls. */
10461 }
10462 }
10463 else
10464 {
10468 /* In the code
10469 template <class T> class C {
10470 template <class U> friend void C1<U>::f (); // case 1
10471 friend void C2<T>::f (); // case 2
10472 };
10473 we only need to make sure CONTEXT is a complete type for
10474 case 2. To distinguish between the two cases, we note that
10475 CONTEXT of case 1 remains dependent type after tsubst while
10476 this isn't true for case 2. */
10486 {
10488 /* do_friend adds the TEMPLATE_DECL for any member friend
10489 template even if it isn't a member template, i.e.
10490 template <class T> friend A<T>::f();
10491 Look through it in that case. */
10495 /* Check to see that the declaration is really present, and,
10496 possibly obtain an improved declaration. */
10501 }
10502 }
10505 }
10507 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
10508 template arguments, as for tsubst.
10510 Returns an appropriate tsubst'd friend type or error_mark_node on
10511 failure. */
10513 static tree
10515 {
10516 tree tmpl;
10519 {
10522 }
10527 else
10535 {
10536 /* The friend template has already been declared. Just
10537 check to see that the declarations match, and install any new
10538 default parameters. We must tsubst the default parameters,
10539 of course. We only need the innermost template parameters
10540 because that is all that redeclare_class_template will look
10541 at. */
10544 {
10552 }
10553 }
10554 else
10555 {
10556 /* The friend template has not already been declared. In this
10557 case, the instantiation of the template class will cause the
10558 injection of this template into the namespace scope. */
10562 {
10563 /* The new TMPL is not an instantiation of anything, so we
10564 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
10565 for the new type because that is supposed to be the
10566 corresponding template decl, i.e., TMPL. */
10573 /* It is hidden. */
10578 /* Inject this template into the enclosing namspace scope. */
10580 }
10581 }
10585 else
10589 }
10591 /* Returns zero if TYPE cannot be completed later due to circularity.
10592 Otherwise returns one. */
10594 static int
10596 {
10606 else
10608 }
10613 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
10614 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
10616 static tree
10619 {
10628 {
10635 clauses
10639 else
10641 }
10642 /* If the first attribute argument is an identifier, don't
10643 pass it through tsubst. Attributes like mode, format,
10644 cleanup and several target specific attributes expect it
10645 unmodified. */
10647 {
10648 tree chain
10653 }
10655 {
10656 /* An attribute pack expansion. */
10665 {
10669 }
10671 }
10672 else
10679 }
10681 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
10682 unchanged or a new TREE_LIST chain. */
10684 static tree
10687 {
10692 {
10696 }
10700 {
10703 {
10706 {
10712 }
10713 }
10715 }
10718 }
10720 /* Apply any attributes which had to be deferred until instantiation
10721 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
10722 ARGS, COMPLAIN, IN_DECL are as tsubst. */
10724 static void
10727 {
10729 tree t;
10736 {
10740 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
10741 to our attributes parameter. */
10743 }
10744 else
10745 {
10747 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
10748 lookup_template_class_1, and should be preserved. */
10752 }
10756 {
10760 }
10764 {
10769 {
10772 {
10778 }
10779 else
10781 }
10784 }
10785 }
10787 /* Perform (or defer) access check for typedefs that were referenced
10788 from within the template TMPL code.
10789 This is a subroutine of instantiate_decl and instantiate_class_template.
10790 TMPL is the template to consider and TARGS is the list of arguments of
10791 that template. */
10793 static void
10795 {
10796 location_t saved_location;
10807 {
10819 /* Make access check error messages point to the location
10820 of the use of the typedef. */
10824 tf_warning_or_error);
10825 }
10827 }
10829 static tree
10831 {
10833 tree typedecl;
10834 tree pbinfo;
10835 tree base_list;
10837 tree fn_context;
10846 /* Figure out which template is being instantiated. */
10850 /* Mark the type as in the process of being defined. */
10853 /* Determine what specialization of the original template to
10854 instantiate. */
10859 {
10860 /* This TYPE is actually an instantiation of a partial
10861 specialization. We replace the innermost set of ARGS with
10862 the arguments appropriate for substitution. For example,
10863 given:
10865 template <class T> struct S {};
10866 template <class T> struct S<T*> {};
10868 and supposing that we are instantiating S<int*>, ARGS will
10869 presently be {int*} -- but we need {int}. */
10872 }
10873 else
10874 {
10877 }
10879 /* If the template we're instantiating is incomplete, then clearly
10880 there's nothing we can do. */
10882 {
10883 /* We can try again later. */
10886 }
10888 /* If we've recursively instantiated too many templates, stop. */
10892 /* We may be in the middle of deferred access check. Disable
10893 it now. */
10900 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10905 else
10906 {
10909 }
10910 /* Use #pragma pack from the template context. */
10916 /* Set the input location to the most specialized template definition.
10917 This is needed if tsubsting causes an error. */
10929 {
10932 /* Adjust visibility for template arguments. */
10934 }
10940 /* We should never instantiate a nested class before its enclosing
10941 class; we need to look up the nested class by name before we can
10942 instantiate it, and that lookup should instantiate the enclosing
10943 class. */
10949 {
10950 tree pbase_binfo;
10951 tree pushed_scope;
10954 /* We must enter the scope containing the type, as that is where
10955 the accessibility of types named in dependent bases are
10956 looked up from. */
10959 /* Substitute into each of the bases to determine the actual
10960 basetypes. */
10962 {
10963 tree base;
10969 {
10970 expanded_bases =
10977 }
10980 {
10982 /* Extract the already-expanded base class. */
10984 else
10985 /* Substitute to figure out the base class. */
10987 NULL_TREE);
10995 }
10996 }
10998 /* The list is now in reverse order; correct that. */
11003 }
11004 /* Now call xref_basetypes to set up all the base-class
11005 information. */
11013 /* Now that our base classes are set up, enter the scope of the
11014 class, so that name lookups into base classes, etc. will work
11015 correctly. This is precisely analogous to what we do in
11016 begin_class_definition when defining an ordinary non-template
11017 class, except we also need to push the enclosing classes. */
11020 /* Now members are processed in the order of declaration. */
11023 {
11027 {
11029 {
11031 /* A closure type for a lambda in an NSDMI or default argument.
11032 Ignore it; it will be regenerated when needed. */
11035 /* Build new CLASSTYPE_NESTED_UTDS. */
11037 tree newtag;
11043 /* If the member is a class template, then -- even after
11044 substitution -- there may be dependent types in the
11045 template argument list for the class. We increment
11046 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
11047 that function will assume that no types are dependent
11048 when outside of a template. */
11058 {
11062 /* Unfortunately, lookup_template_class sets
11063 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
11064 instantiation (i.e., for the type of a member
11065 template class nested within a template class.)
11066 This behavior is required for
11067 maybe_process_partial_specialization to work
11068 correctly, but is not accurate in this case;
11069 the TAG is not an instantiation of anything.
11070 (The corresponding TEMPLATE_DECL is an
11071 instantiation, but the TYPE is not.) */
11074 /* Now, we call pushtag to put this NEWTAG into the scope of
11075 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
11076 pushtag calling push_template_decl. We don't have to do
11077 this for enums because it will already have been done in
11078 tsubst_enum. */
11082 }
11083 }
11085 {
11086 tree r;
11095 /* Instantiate members marked with attribute used. */
11101 }
11104 /* A closure type for a lambda in an NSDMI or default argument.
11106 else
11107 {
11108 /* Build new TYPE_FIELDS. */
11110 {
11111 tree condition;
11114 condition =
11124 }
11126 {
11127 tree r;
11131 /* The file and line for this declaration, to
11132 assist in error message reporting. Since we
11133 called push_tinst_level above, we don't need to
11134 restore these. */
11144 {
11145 /* A capture pack became multiple fields. */
11148 }
11151 {
11155 {
11156 /* In [temp.inst]:
11158 [t]he initialization (and any associated
11159 side-effects) of a static data member does
11160 not occur unless the static data member is
11161 itself used in a way that requires the
11162 definition of the static data member to
11163 exist.
11165 Therefore, we do not substitute into the
11166 initialized for the static data member here. */
11167 finish_static_data_member_decl
11173 /* Instantiate members marked with attribute used. */
11176 }
11178 {
11179 /* Determine whether R has a valid type and can be
11180 completed later. If R is invalid, then its type
11181 is replaced by error_mark_node. */
11187 {
11188 /* If R's type couldn't be completed and
11189 it isn't a flexible array member (whose
11190 type is incomplete by definition) give
11191 an error. */
11194 }
11199 {
11202 }
11203 }
11205 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
11206 such a thing will already have been added to the field
11207 list by tsubst_enum in finish_member_declaration in the
11208 CLASSTYPE_NESTED_UTDS case above. */
11212 {
11215 }
11216 }
11217 }
11218 }
11219 }
11220 else
11221 {
11224 {
11225 /* Build new CLASSTYPE_FRIEND_CLASSES. */
11231 {
11232 /* template <class T> friend class C; */
11235 }
11237 {
11238 /* template <class T> friend class C::D; */
11244 }
11247 {
11248 /* This could be either
11250 friend class T::C;
11252 when dependent_type_p is false or
11254 template <class U> friend class T::C;
11256 otherwise. */
11257 /* Bump processing_template_decl in case this is something like
11258 template <class T> friend struct A<T>::B. */
11265 }
11269 {
11270 /* friend class C;
11272 where C hasn't been declared yet. Let's lookup name
11273 from namespace scope directly, bypassing any name that
11274 come from dependent base class. */
11277 /* The call to xref_tag_from_type does injection for friend
11278 classes. */
11280 friend_type =
11284 }
11286 /* friend class C<T>; */
11289 /* Otherwise it's
11291 friend class C;
11293 where C is already declared or
11295 friend class C<int>;
11297 We don't have to do anything in these cases. */
11300 /* Trick make_friend_class into realizing that the friend
11301 we're adding is a template, not an ordinary class. It's
11302 important that we use make_friend_class since it will
11303 perform some error-checking and output cross-reference
11304 information. */
11312 }
11313 else
11314 {
11315 /* Build new DECL_FRIENDLIST. */
11316 tree r;
11318 /* The file and line for this declaration, to
11319 assist in error message reporting. Since we
11320 called push_tinst_level above, we don't need to
11321 restore these. */
11325 {
11328 }
11333 {
11336 }
11337 }
11338 }
11339 }
11342 {
11343 /* Restore these before substituting into the lambda capture
11344 initializers. */
11347 }
11349 /* Set the file and line number information to whatever is given for
11350 the class itself. This puts error messages involving generated
11351 implicit functions at a predictable point, and the same point
11352 that would be used for non-template classes. */
11359 /* We don't instantiate default arguments for member functions. 14.7.1:
11361 The implicit instantiation of a class template specialization causes
11362 the implicit instantiation of the declarations, but not of the
11363 definitions or default arguments, of the class member functions,
11364 member classes, static data members and member templates.... */
11366 /* Some typedefs referenced from within the template code need to be access
11367 checked at template instantiation time, i.e now. These types were
11368 added to the template at parsing time. Let's get those and perform
11369 the access checks then. */
11379 /* The vtable for a template class can be emitted in any translation
11380 unit in which the class is instantiated. When there is no key
11381 method, however, finish_struct_1 will already have added TYPE to
11382 the keyed_classes. */
11387 }
11389 /* Wrapper for instantiate_class_template_1. */
11391 tree
11393 {
11394 tree ret;
11399 }
11401 static tree
11403 {
11404 tree r;
11410 else
11411 {
11418 }
11420 }
11422 /* Given a function parameter pack TMPL_PARM and some function parameters
11423 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
11424 and set *SPEC_P to point at the next point in the list. */
11426 tree
11428 {
11429 /* Collect all of the extra "packed" parameters into an
11430 argument pack. */
11431 tree parmvec;
11441 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
11445 {
11450 }
11452 /* Build the argument packs. */
11457 }
11459 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
11460 NONTYPE_ARGUMENT_PACK. */
11462 static tree
11464 {
11466 }
11468 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
11469 pack expansion with no extra args, 2 if it has extra args, or 0
11470 if it is not a pack expansion. */
11472 static int
11474 {
11480 /* A decl pack is itself an expansion. */
11487 }
11490 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
11492 static tree
11494 {
11501 }
11503 /* This is a subroutine of tsubst_pack_expansion.
11505 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
11506 mechanism to store the (non complete list of) arguments of the
11507 substitution and return a non substituted pack expansion, in order
11508 to wait for when we have enough arguments to really perform the
11509 substitution. */
11511 static bool
11515 {
11516 /* If one pack has an expansion and another pack has a normal
11517 argument or if one pack has an empty argument and an another
11518 one hasn't then tsubst_pack_expansion cannot perform the
11519 substitution and need to fall back on the
11520 PACK_EXPANSION_EXTRA mechanism. */
11528 {
11531 parm_pack;
11533 {
11538 /* We can't substitute a pack expansion with extra args into
11539 our pattern. */
11543 else
11545 }
11549 }
11551 }
11553 /* [temp.variadic]/6 says that:
11555 The instantiation of a pack expansion [...]
11556 produces a list E1,E2, ..., En, where N is the number of elements
11557 in the pack expansion parameters.
11559 This subroutine of tsubst_pack_expansion produces one of these Ei.
11561 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
11562 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
11563 PATTERN, and each TREE_VALUE is its corresponding argument pack.
11564 INDEX is the index 'i' of the element Ei to produce. ARGS,
11565 COMPLAIN, and IN_DECL are the same parameters as for the
11566 tsubst_pack_expansion function.
11568 The function returns the resulting Ei upon successful completion,
11569 or error_mark_node.
11571 Note that this function possibly modifies the ARGS parameter, so
11572 it's the responsibility of the caller to restore it. */
11574 static tree
11576 tree parm_packs,
11578 tree args /* This parm gets
11580 tsubst_flags_t complain,
11581 tree in_decl)
11582 {
11583 tree t;
11586 /* For each parameter pack, change the substitution of the parameter
11587 pack to the ith argument in its argument pack, then expand the
11588 pattern. */
11590 {
11595 ith_elem_is_expansion |=
11598 /* Select the Ith argument from the pack. */
11602 {
11604 {
11609 }
11610 else
11612 }
11613 else
11614 {
11619 {
11621 /* Update the corresponding argument. */
11623 }
11624 else
11625 /* Re-use the ARGUMENT_PACK_SELECT. */
11627 }
11629 }
11631 /* Substitute into the PATTERN with the (possibly altered)
11632 arguments. */
11634 /* Expanding a fixed parameter pack from
11635 coerce_template_parameter_pack. */
11640 {
11643 else
11646 }
11650 else
11653 /* If the Ith argument pack element is a pack expansion, then
11654 the Ith element resulting from the substituting is going to
11655 be a pack expansion as well. */
11660 }
11662 /* When the unexpanded parameter pack in a fold expression expands to an empty
11663 sequence, the value of the expression is as follows; the program is
11664 ill-formed if the operator is not listed in this table.
11666 && true
11667 || false
11668 , void() */
11670 tree
11672 {
11676 {
11685 }
11691 }
11693 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11694 form an expression that combines the two terms using the
11695 operator of T. */
11697 static tree
11699 {
11703 // Handle compound assignment operators.
11708 {
11718 complain);
11719 }
11720 }
11722 /* Substitute ARGS into the pack of a fold expression T. */
11726 {
11728 }
11730 /* Substitute ARGS into the pack of a fold expression T. */
11734 {
11736 }
11738 /* Expand a PACK of arguments into a grouped as left fold.
11739 Given a pack containing elements A0, A1, ..., An and an
11740 operator @, this builds the expression:
11742 ((A0 @ A1) @ A2) ... @ An
11744 Note that PACK must not be empty.
11746 The operator is defined by the original fold expression T. */
11748 static tree
11750 {
11753 {
11756 }
11758 }
11760 /* Substitute into a unary left fold expression. */
11762 static tree
11764 tree in_decl)
11765 {
11770 {
11774 }
11777 else
11779 }
11781 /* Substitute into a binary left fold expression.
11783 Do ths by building a single (non-empty) vector of argumnts and
11784 building the expression from those elements. */
11786 static tree
11788 tree in_decl)
11789 {
11798 {
11803 }
11811 }
11813 /* Expand a PACK of arguments into a grouped as right fold.
11814 Given a pack containing elementns A0, A1, ..., and an
11815 operator @, this builds the expression:
11817 A0@ ... (An-2 @ (An-1 @ An))
11819 Note that PACK must not be empty.
11821 The operator is defined by the original fold expression T. */
11823 tree
11825 {
11826 // Build the expression.
11830 {
11833 }
11835 }
11837 /* Substitute into a unary right fold expression. */
11839 static tree
11841 tree in_decl)
11842 {
11847 {
11851 }
11854 else
11856 }
11858 /* Substitute into a binary right fold expression.
11860 Do ths by building a single (non-empty) vector of arguments and
11861 building the expression from those elements. */
11863 static tree
11865 tree in_decl)
11866 {
11875 {
11880 }
11889 }
11891 /* Walk through the pattern of a pack expansion, adding everything in
11892 local_specializations to a list. */
11894 struct el_data
11895 {
11897 tree extra;
11898 tsubst_flags_t complain;
11902 };
11903 static tree
11905 {
11911 /* Remember local typedefs (85214). */
11917 {
11919 /* Don't mess with variables declared within the pattern. */
11922 {
11923 /* Maybe pull out the PARM_DECL for a partial instantiation. */
11926 {
11932 }
11934 {
11935 /* Handle lambda capture here, since we aren't doing any
11936 substitution now, and so tsubst_copy won't call
11937 process_outer_var_ref. */
11941 {
11947 {
11948 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
11949 proxies. */
11951 {
11956 }
11958 }
11959 }
11960 }
11961 }
11965 }
11967 }
11968 static tree
11970 {
11974 }
11976 /* Extract any uses of local_specializations from PATTERN and add them to ARGS
11977 for use in PACK_EXPANSION_EXTRA_ARGS. */
11979 tree
11981 {
11987 }
11989 /* Apply any local specializations from PACK_EXPANSION_EXTRA_ARGS and add the
11990 normal template args to ARGS. */
11992 tree
11994 {
11996 {
11998 {
11999 /* The partial instantiation involved local declarations collected in
12000 extract_local_specs; map from the general template to our local
12001 context. */
12007 /* else inst is already a full instantiation of the pack. */
12009 }
12012 }
12014 }
12016 /* Substitute ARGS into T, which is an pack expansion
12017 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
12018 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
12019 (if only a partial substitution could be performed) or
12020 ERROR_MARK_NODE if there was an error. */
12021 tree
12023 tree in_decl)
12024 {
12025 tree pattern;
12030 tree result;
12038 /* Add in any args remembered from an earlier partial instantiation. */
12043 /* Determine the argument packs that will instantiate the parameter
12044 packs used in the expansion expression. While we're at it,
12045 compute the number of arguments to be expanded and make sure it
12046 is consistent. */
12049 {
12056 {
12062 complain);
12063 else
12067 }
12069 {
12070 /* ??? Support use in other patterns. */
12074 }
12076 {
12077 /* We know we have correct local_specializations if this
12078 expansion is at function scope, or if we're dealing with a
12079 local parameter in a requires expression; for the latter,
12080 tsubst_requires_expr set it up appropriately. */
12083 else
12084 /* We can't rely on local_specializations for a parameter
12085 name used later in a function declaration (such as in a
12086 late-specified return type). Even if it exists, it might
12087 have the wrong value for a recursive call. */
12091 {
12092 /* This parameter pack was used in an unevaluated context. Just
12093 make a dummy decl, since it's only used for its type. */
12098 /* Partial instantiation of the parm_pack, we can't build
12099 up an argument pack yet. */
12101 else
12103 }
12105 /* This argument pack isn't fully instantiated yet. We set this
12106 flag rather than clear arg_pack because we do want to do the
12107 optimization below, and we don't want to substitute directly
12108 into the pattern (as that would expose a NONTYPE_ARGUMENT_PACK
12109 where it isn't expected). */
12111 }
12113 {
12117 }
12118 else
12119 {
12125 }
12132 /* This can only happen if we forget to expand an argument
12133 pack somewhere else. Just return an error, silently. */
12134 {
12138 }
12141 {
12145 /* Don't bother trying to do a partial substitution with
12146 incomplete packs; we'll try again after deduction. */
12154 {
12159 pattern);
12160 else
12162 pattern);
12164 }
12166 /* Keep track of the parameter packs and their corresponding
12167 argument packs. */
12170 }
12171 else
12172 {
12173 /* We can't substitute for this parameter pack. We use a flag as
12174 well as the missing_level counter because function parameter
12175 packs don't have a level. */
12178 }
12179 }
12181 /* If the expansion is just T..., return the matching argument pack, unless
12182 we need to call convert_from_reference on all the elements. This is an
12183 important optimization; see c++/68422. */
12186 {
12189 /* If the argument pack is a single pack expansion, pull it out. */
12194 /* Types need no adjustment, nor does sizeof..., and if we still have
12195 some pack expansion args we won't do anything yet. */
12200 /* Also optimize expression pack expansions if we can tell that the
12201 elements won't have reference type. */
12207 /* Otherwise use the normal path so we get convert_from_reference. */
12208 }
12210 /* We cannot expand this expansion expression, because we don't have
12211 all of the argument packs we need. */
12213 {
12214 /* We got some full packs, but we can't substitute them in until we
12215 have values for all the packs. So remember these until then. */
12221 }
12223 {
12224 /* There were no real arguments, we're just replacing a parameter
12225 pack with another version of itself. Substitute into the
12226 pattern and return a PACK_EXPANSION_*. The caller will need to
12227 deal with that. */
12231 else
12235 }
12240 {
12241 /* We're in a late-specified return type, so create our own local
12242 specializations map; the current map is either NULL or (in the
12243 case of recursive unification) might have bindings that we don't
12244 want to use or alter. */
12247 }
12249 /* For each argument in each argument pack, substitute into the
12250 pattern. */
12254 {
12256 i,
12258 in_decl);
12261 {
12264 }
12265 }
12267 /* Update ARGS to restore the substitution from parameter packs to
12268 their argument packs. */
12270 {
12277 else
12278 {
12286 /* Update the corresponding argument. */
12290 else
12292 }
12293 }
12296 {
12299 }
12301 /* If the dependent pack arguments were such that we end up with only a
12302 single pack expansion again, there's no need to keep it in a TREE_VEC. */
12308 }
12310 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
12311 TMPL. We do this using DECL_PARM_INDEX, which should work even with
12312 parameter packs; all parms generated from a function parameter pack will
12313 have the same DECL_PARM_INDEX. */
12315 tree
12317 {
12319 tree patparm;
12322 {
12328 }
12329 else
12330 {
12335 }
12338 }
12340 /* Make an argument pack out of the TREE_VEC VEC. */
12342 static tree
12344 {
12345 tree pack;
12349 else
12350 {
12353 }
12356 }
12358 /* Return an exact copy of template args T that can be modified
12359 independently. */
12361 static tree
12363 {
12371 {
12376 }
12382 }
12384 /* Substitute ARGS into the vector or list of template arguments T. */
12386 static tree
12388 {
12400 {
12402 tree new_arg;
12407 {
12408 /* Substitute into an expansion expression. */
12412 /* Add to the expanded length adjustment the number of
12413 expanded arguments. We subtract one from this
12414 measurement, because the argument pack expression
12415 itself is already counted as 1 in
12416 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
12417 the argument pack is empty. */
12419 }
12421 {
12422 /* Substitute into each of the arguments. */
12431 else
12436 }
12437 else
12446 }
12451 /* Make space for the expanded arguments coming from template
12452 argument packs. */
12454 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
12455 arguments for a member template.
12456 In that case each TREE_VEC in ORIG_T represents a level of template
12457 arguments, and ORIG_T won't carry any non defaulted argument count.
12458 It will rather be the nested TREE_VECs that will carry one.
12459 In other words, ORIG_T carries a non defaulted argument count only
12460 if it doesn't contain any nested TREE_VEC. */
12462 {
12466 }
12468 {
12472 {
12475 /* Now expand the template argument pack "in place". */
12478 }
12479 else
12480 {
12482 out++;
12483 }
12484 }
12487 }
12489 /* Substitute ARGS into one level PARMS of template parameters. */
12491 static tree
12493 {
12500 {
12508 }
12511 }
12513 /* Return the result of substituting ARGS into the template parameters
12514 given by PARMS. If there are m levels of ARGS and m + n levels of
12515 PARMS, then the result will contain n levels of PARMS. For
12516 example, if PARMS is `template <class T> template <class U>
12517 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
12518 result will be `template <int*, double, class V>'. */
12520 static tree
12522 {
12526 /* When substituting into a template, we must set
12527 PROCESSING_TEMPLATE_DECL as the template parameters may be
12528 dependent if they are based on one-another, and the dependency
12529 predicates are short-circuit outside of templates. */
12536 {
12543 }
12548 }
12550 /* Return the result of substituting ARGS into one template parameter
12551 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
12552 parameter and which TREE_PURPOSE is the default argument of the
12553 template parameter. */
12555 static tree
12557 {
12578 }
12580 /* Substitute the ARGS into the indicated aggregate (or enumeration)
12581 type T. If T is not an aggregate or enumeration type, it is
12582 handled as if by tsubst. IN_DECL is as for tsubst. If
12583 ENTERING_SCOPE is nonzero, T is the context for a template which
12584 we are presently tsubst'ing. Return the substituted value. */
12586 static tree
12588 tree args,
12589 tsubst_flags_t complain,
12590 tree in_decl,
12592 {
12597 {
12602 /* Fall through. */
12606 {
12607 tree argvec;
12608 tree context;
12609 tree r;
12613 /* In "sizeof(X<I>)" we need to evaluate "I". */
12619 /* First, determine the context for the type we are looking
12620 up. */
12623 {
12626 /* If context is a nested class inside a class template,
12627 it may still need to be instantiated (c++/33959). */
12629 }
12631 /* Then, figure out what arguments are appropriate for the
12632 type we are trying to find. For example, given:
12634 template <class T> struct S;
12635 template <class T, class U> void f(T, U) { S<U> su; }
12637 and supposing that we are instantiating f<int, double>,
12638 then our ARGS will be {int, double}, but, when looking up
12639 S we only want {double}. */
12644 else
12645 {
12649 }
12655 }
12656 else
12657 /* This is not a template type, so there's nothing to do. */
12662 }
12663 }
12667 /* Substitute into the default argument ARG (a default argument for
12668 FN), which has the indicated TYPE. */
12670 tree
12672 tsubst_flags_t complain)
12673 {
12678 /* This can happen in invalid code. */
12696 /* This default argument came from a template. Instantiate the
12697 default argument here, not in tsubst. In the case of
12698 something like:
12700 template <class T>
12701 struct S {
12702 static T t();
12703 void f(T = t());
12704 };
12706 we must be careful to do name lookup in the scope of S<T>,
12707 rather than in the current class. */
12709 /* The "this" pointer is not valid in a default argument. */
12711 {
12716 }
12721 /* The default argument expression may cause implicitly defined
12722 member functions to be synthesized, which will result in garbage
12723 collection. We must treat this situation as if we were within
12724 the body of function so as to avoid collecting live data on the
12725 stack. */
12735 /* Restore the "this" pointer. */
12737 {
12740 }
12747 /* Make sure the default argument is reasonable. */
12753 {
12757 }
12760 }
12762 /* Substitute into all the default arguments for FN. */
12764 static void
12766 {
12767 tree arg;
12768 tree tmpl_args;
12772 /* If this function is not yet instantiated, we certainly don't need
12773 its default arguments. */
12776 /* Don't do this again for clones. */
12782 arg;
12788 complain);
12789 }
12791 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
12793 static tree
12795 tree lambda_fntype)
12796 {
12801 /* Nobody should be tsubst'ing into non-template functions. */
12805 {
12806 /* If T is not dependent, just return it. */
12810 /* Calculate the most general template of which R is a
12811 specialization. */
12814 /* We're substituting a lambda function under tsubst_lambda_expr but not
12815 directly from it; find the matching function we're already inside.
12816 But don't do this if T is a generic lambda with a single level of
12817 template parms, as in that case we're doing a normal instantiation. */
12823 /* Calculate the complete set of arguments used to
12824 specialize R. */
12826 (DECL_TEMPLATE_RESULT
12832 /* Check to see if we already have this specialization. */
12834 {
12838 }
12840 /* We can see more levels of arguments than parameters if
12841 there was a specialization of a member template, like
12842 this:
12844 template <class T> struct S { template <class U> void f(); }
12845 template <> template <class U> void S<int>::f(U);
12847 Here, we'll be substituting into the specialization,
12848 because that's where we can find the code we actually
12849 want to generate, but we'll have enough arguments for
12850 the most general template.
12852 We also deal with the peculiar case:
12854 template <class T> struct S {
12855 template <class U> friend void f();
12856 };
12857 template <class U> void f() {}
12858 template S<int>;
12859 template void f<double>();
12861 Here, the ARGS for the instantiation of will be {int,
12862 double}. But, we only need as many ARGS as there are
12863 levels of template parameters in CODE_PATTERN. We are
12864 careful not to get fooled into reducing the ARGS in
12865 situations like:
12867 template <class T> struct S { template <class U> void f(U); }
12868 template <class T> template <> void S<T>::f(int) {}
12870 which we can spot because the pattern will be a
12871 specialization in this case. */
12878 }
12879 else
12880 {
12881 /* This special case arises when we have something like this:
12883 template <class T> struct S {
12884 friend void f<int>(int, double);
12885 };
12887 Here, the DECL_TI_TEMPLATE for the friend declaration
12888 will be an IDENTIFIER_NODE. We are being called from
12889 tsubst_friend_function, and we want only to create a
12890 new decl (R) with appropriate types so that we can call
12891 determine_specialization. */
12894 }
12911 /* If we hit excessive deduction depth, the type is bogus even if
12912 it isn't error_mark_node, so don't build a decl. */
12916 /* We do NOT check for matching decls pushed separately at this
12917 point, as they may not represent instantiations of this
12918 template, and in any case are considered separate under the
12919 discrete model. */
12923 /* Clear out the mangled name and RTL for the instantiation. */
12926 /* Leave DECL_INITIAL set on deleted instantiations. */
12931 /* OpenMP UDRs have the only argument a reference to the declared
12932 type. We want to diagnose if the declared type is a reference,
12933 which is invalid, but as references to references are usually
12934 quietly merged, diagnose it here. */
12936 {
12937 tree argtype
12942 "reference type %qT in "
12946 argtype);
12947 }
12950 /* Type-conversion operator. Reconstruct the name, in
12951 case it's the name of one of the template's parameters. */
12961 {
12965 }
12972 /* If this is an instantiation of a function with internal
12973 linkage, we already know what object file linkage will be
12974 assigned to the instantiation. */
12983 /* We'll re-clone as appropriate in instantiate_template. */
12986 /* If we aren't complaining now, return on error before we register
12987 the specialization so that we'll complain eventually. */
12993 /* When instantiating a constrained member, substitute
12994 into the constraints to create a new constraint. */
12997 {
13000 }
13002 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
13003 this in the special friend case mentioned above where
13004 GEN_TMPL is NULL. */
13006 {
13011 tree new_r
13014 /* We instantiated this while substituting into
13015 the type earlier (template/friend54.C). */
13018 /* We're not supposed to instantiate default arguments
13019 until they are called, for a template. But, for a
13020 declaration like:
13022 template <class T> void f ()
13023 { extern void g(int i = T()); }
13025 we should do the substitution when the template is
13026 instantiated. We handle the member function case in
13027 instantiate_class_template since the default arguments
13028 might refer to other members of the class. */
13033 }
13034 else
13037 /* Copy the list of befriending classes. */
13041 {
13045 }
13048 {
13052 /* If this is an instantiation of a member template, clone it.
13053 If it isn't, that'll be handled by
13054 clone_constructors_and_destructors. */
13057 }
13068 /* Possibly limit visibility based on template args. */
13071 {
13075 }
13084 }
13086 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
13088 static tree
13090 tree lambda_fntype)
13091 {
13092 /* We can get here when processing a member function template,
13093 member class template, or template template parameter. */
13096 tree spec;
13097 tree tmpl_args;
13098 tree full_args;
13099 tree r;
13103 {
13104 /* Template template parameter is treated here. */
13108 /* If we get a real template back, return it. This can happen in
13109 the context of most_specialized_partial_spec. */
13112 else
13113 /* The new TEMPLATE_DECL was built in
13114 reduce_template_parm_level. */
13117 }
13120 {
13121 /* We might already have an instance of this template.
13122 The ARGS are for the surrounding class type, so the
13123 full args contain the tsubst'd args for the context,
13124 plus the innermost args from the template decl. */
13128 /* Because this is a template, the arguments will still be
13129 dependent, even after substitution. If
13130 PROCESSING_TEMPLATE_DECL is not set, the dependency
13131 predicates will short-circuit. */
13139 /* If this is a default template template argument,
13140 tsubst might not have changed anything. */
13148 }
13150 /* Make a new template decl. It will be similar to the
13151 original, but will record the current template arguments.
13152 We also create a new function declaration, which is just
13153 like the old one, but points to this new template, rather
13154 than the old one. */
13159 // Build new template info linking to the original template decl.
13161 {
13164 }
13165 else
13168 /* The template parameters for this new template are all the
13169 template parameters for the old template, except the
13170 outermost level of parameters. */
13173 complain);
13177 {
13178 tree new_type;
13186 /* For a partial specialization, we need to keep pointing to
13187 the primary template. */
13193 }
13194 else
13195 {
13196 tree new_decl;
13200 else
13210 {
13213 }
13214 else
13215 {
13218 }
13219 }
13229 /* Record this non-type partial instantiation. */
13235 }
13237 /* True if FN is the op() for a lambda in an uninstantiated template. */
13239 bool
13241 {
13246 }
13248 /* We're instantiating a variable from template function TCTX. Return the
13249 corresponding current enclosing scope. This gets complicated because lambda
13250 functions in templates are regenerated rather than instantiated, but generic
13251 lambda functions are subsequently instantiated. */
13253 static tree
13255 {
13264 {
13277 }
13279 }
13281 /* Substitute the ARGS into the T, which is a _DECL. Return the
13282 result of the substitution. Issue error and warning messages under
13283 control of COMPLAIN. */
13285 static tree
13287 {
13288 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
13289 location_t saved_loc;
13294 /* Set the filename and linenumber to improve error-reporting. */
13299 {
13309 {
13317 {
13318 /* If there is a local specialization that isn't a
13319 parameter pack, it means that we're doing a "simple"
13320 substitution from inside tsubst_pack_expansion. Just
13321 return the local specialization (which will be a single
13322 parm). */
13329 /* Expand the TYPE_PACK_EXPANSION that provides the types for
13330 the parameters in this function parameter pack. */
13334 {
13337 /* Zero-length parameter packs are boring. Just substitute
13338 into the chain. */
13342 }
13343 else
13344 {
13345 /* All we did was update the type. Make a note of that. */
13348 }
13349 }
13351 /* Loop through all of the parameters we'll build. When T is
13352 a function parameter pack, LEN is the number of expanded
13353 types in EXPANDED_TYPES; otherwise, LEN is 1. */
13356 {
13363 /* We're on the Ith parameter of the function parameter
13364 pack. */
13365 {
13366 /* Get the Ith type. */
13369 /* Rename the parameter to include the index. */
13372 }
13374 /* We're dealing with a normal parameter. */
13382 {
13385 else
13388 }
13398 /* Keep track of the first new parameter we
13399 generate. That's what will be returned to the
13400 caller. */
13404 /* Build a proper chain of parameters when substituting
13405 into a function parameter pack. */
13408 }
13410 /* If cp_unevaluated_operand is set, we're just looking for a
13411 single dummy parameter, so don't keep going. */
13416 /* FIRST_R contains the start of the chain we've built. */
13418 }
13422 {
13429 {
13430 /* This field is a lambda capture pack. Return a TREE_VEC of
13431 the expanded fields to instantiate_class_template_1. */
13435 {
13438 }
13439 else
13440 {
13441 /* All we did was update the type. Make a note of that. */
13444 }
13445 }
13448 {
13451 {
13455 }
13465 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
13466 number of bits. */
13472 {
13473 /* Set up DECL_TEMPLATE_INFO so that we can get at the
13474 NSDMI in perform_member_init. Still set DECL_INITIAL
13475 so that we know there is one. */
13480 }
13481 /* We don't have to set DECL_CONTEXT here; it is set by
13482 finish_member_declaration. */
13490 }
13494 }
13498 /* We reach here only for member using decls. We also need to check
13499 uses_template_parms because DECL_DEPENDENT_P is not set for a
13500 using-declaration that designates a member of the current
13501 instantiation (c++/53549). */
13504 {
13508 {
13513 {
13517 {
13520 }
13521 else
13522 {
13525 }
13527 }
13528 }
13529 else
13530 {
13536 else
13537 {
13540 }
13541 }
13542 }
13543 else
13544 {
13547 }
13552 {
13555 tree spec;
13557 tree ctx;
13566 {
13567 /* If this is the canonical decl, we don't have to
13568 mess with instantiations, and often we can't (for
13569 typename, template type parms and such). Note that
13570 TYPE_NAME is not correct for the above test if
13571 we've copied the type for a typedef. */
13577 }
13579 /* Check to see if we already have the specialization we
13580 need. */
13583 {
13584 /* T is a static data member or namespace-scope entity.
13585 We have to substitute into namespace-scope variables
13586 (not just variable templates) because of cases like:
13588 template <class T> void f() { extern T t; }
13590 where the entity referenced is not known until
13591 instantiation time. */
13595 {
13597 complain,
13599 /* If CTX is unchanged, then T is in fact the
13600 specialization we want. That situation occurs when
13601 referencing a static data member within in its own
13602 class. We can use pointer equality, rather than
13603 same_type_p, because DECL_CONTEXT is always
13604 canonical... */
13606 /* ... unless T is a member template; in which
13607 case our caller can be willing to create a
13608 specialization of that template represented
13609 by T. */
13613 }
13616 {
13621 argvec = (coerce_innermost_template_parms
13629 }
13630 }
13631 else
13632 {
13633 /* A local variable. */
13635 /* Subsequent calls to pushdecl will fill this in. */
13637 /* Unless this is a reference to a static variable from an
13638 enclosing function, in which case we need to fill it in now. */
13640 {
13644 }
13646 }
13647 /* If we already have the specialization we need, there is
13648 nothing more to do. */
13650 {
13653 }
13655 /* Create a new node for the specialization we need. */
13658 {
13661 else
13669 {
13670 /* Mask off any template args past the variable's context so we
13671 don't replace the auto with an unrelated argument. */
13675 /* This should never happen with the new lambda instantiation
13676 model, but keep the handling just in case. */
13679 }
13681 }
13683 {
13689 {
13690 /* It may seem that this case cannot occur, since:
13692 typedef void f();
13693 void g() { f x; }
13695 declares a function, not a variable. However:
13697 typedef void f();
13698 template <typename T> void g() { T t; }
13699 template void g<f>();
13701 is an attempt to declare a variable with function
13702 type. */
13704 /* R is not yet sufficiently initialized, so we
13705 just use its name. */
13708 }
13710 /* Wait until cp_finish_decl to set this again, to handle
13711 circular dependency (template/instantiate6.C). */
13716 {
13721 {
13724 }
13726 }
13730 }
13736 /* Clear out the mangled name and RTL for the instantiation. */
13740 /* The initializer must not be expanded until it is required;
13741 see [temp.inst]. */
13745 {
13751 /* Possibly limit visibility based on template args. */
13754 {
13758 }
13760 }
13763 {
13764 /* A static data member declaration is always marked
13765 external when it is declared in-class, even if an
13766 initializer is present. We mimic the non-template
13767 processing here. */
13775 }
13776 else
13777 {
13782 }
13790 /* Preserve a typedef that names a type. */
13792 {
13796 /* An alias template specialization can be dependent
13797 even if its underlying type is not. */
13799 }
13802 }
13807 }
13808 #undef RETURN
13810 out:
13811 /* Restore the file and line information. */
13815 }
13817 /* Substitute into the ARG_TYPES of a function type.
13818 If END is a TREE_CHAIN, leave it and any following types
13819 un-substituted. */
13821 static tree
13823 tree args,
13824 tree end,
13825 tsubst_flags_t complain,
13826 tree in_decl)
13827 {
13828 tree remaining_arg_types;
13832 tree default_arg;
13843 {
13844 /* For a pack expansion, perform substitution on the
13845 entire expression. Later on, we'll handle the arguments
13846 one-by-one. */
13851 /* So that we'll spin through the parameters, one by one. */
13853 else
13854 {
13855 /* We only partially substituted into the parameter
13856 pack. Our type is TYPE_PACK_EXPANSION. */
13859 }
13860 }
13873 {
13875 {
13879 }
13881 }
13882 /* DR 657. */
13886 /* Do array-to-pointer, function-to-pointer conversion, and ignore
13887 top-level qualifiers as required. */
13890 /* We do not substitute into default arguments here. The standard
13891 mandates that they be instantiated only when needed, which is
13892 done in build_over_call. */
13895 /* Except that we do substitute default arguments under tsubst_lambda_expr,
13896 since the new op() won't have any associated template arguments for us
13897 to refer to later. */
13903 {
13904 /* We've instantiated a template before its default arguments
13905 have been parsed. This can happen for a nested template
13906 class, and is not an error unless we require the default
13907 argument in a call of this function. */
13908 remaining_arg_types =
13911 }
13912 else
13913 remaining_arg_types =
13915 }
13918 }
13920 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
13921 *not* handle the exception-specification for FNTYPE, because the
13922 initial substitution of explicitly provided template parameters
13923 during argument deduction forbids substitution into the
13924 exception-specification:
13926 [temp.deduct]
13928 All references in the function type of the function template to the
13929 corresponding template parameters are replaced by the specified tem-
13930 plate argument values. If a substitution in a template parameter or
13931 in the function type of the function template results in an invalid
13932 type, type deduction fails. [Note: The equivalent substitution in
13933 exception specifications is done only when the function is instanti-
13934 ated, at which point a program is ill-formed if the substitution
13935 results in an invalid type.] */
13937 static tree
13939 tree args,
13940 tsubst_flags_t complain,
13941 tree in_decl)
13942 {
13943 tree return_type;
13945 tree fntype;
13947 /* The TYPE_CONTEXT is not used for function/method types. */
13950 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
13951 failure. */
13955 {
13956 /* Substitute the argument types. */
13968 {
13969 /* DR 1207: 'this' is in scope in the trailing return type. */
13971 }
13973 /* Substitute the return type. */
13977 {
13980 }
13981 }
13982 else
13983 /* Substitute the return type. */
13988 /* DR 486 clarifies that creation of a function type with an
13989 invalid return type is a deduction failure. */
13992 {
13994 {
13997 else
13999 }
14001 }
14002 /* And DR 657. */
14007 {
14008 /* Substitute the argument types. */
14013 }
14015 /* Construct a new type node and return it. */
14017 {
14020 }
14021 else
14022 {
14024 /* Don't pick up extra function qualifiers from the basetype. */
14027 {
14028 /* [temp.deduct]
14030 Type deduction may fail for any of the following
14031 reasons:
14033 -- Attempting to create "pointer to member of T" when T
14034 is not a class type. */
14037 r);
14039 }
14043 }
14046 /* See comment above. */
14052 }
14054 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
14055 ARGS into that specification, and return the substituted
14056 specification. If there is no specification, return NULL_TREE. */
14058 static tree
14060 tree args,
14061 tsubst_flags_t complain,
14062 tree in_decl,
14064 {
14065 tree specs;
14066 tree new_specs;
14071 {
14072 /* A noexcept-specifier. */
14077 {
14078 /* Defer instantiation of noexcept-specifiers to avoid
14079 excessive instantiations (c++/49107). */
14082 {
14083 /* We already partially instantiated this member template,
14084 so combine the new args with the old. */
14089 }
14090 else
14091 {
14094 }
14095 }
14096 else
14097 new_specs = tsubst_copy_and_build
14101 }
14103 {
14106 else
14108 {
14109 tree spec;
14114 {
14115 /* Expand the pack expansion type. */
14118 in_decl);
14124 else
14125 {
14126 /* We're substituting into a member template, so
14127 we got a TYPE_PACK_EXPANSION back. Add that
14128 expansion and move on. */
14132 expanded_specs,
14133 complain);
14136 }
14137 }
14140 {
14143 else
14148 complain);
14149 }
14152 }
14153 }
14155 }
14157 /* Take the tree structure T and replace template parameters used
14158 therein with the argument vector ARGS. IN_DECL is an associated
14159 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
14160 Issue error and warning messages under control of COMPLAIN. Note
14161 that we must be relatively non-tolerant of extensions here, in
14162 order to preserve conformance; if we allow substitutions that
14163 should not be allowed, we may allow argument deductions that should
14164 not succeed, and therefore report ambiguous overload situations
14165 where there are none. In theory, we could allow the substitution,
14166 but indicate that it should have failed, and allow our caller to
14167 make sure that the right thing happens, but we don't try to do this
14168 yet.
14170 This function is used for dealing with types, decls and the like;
14171 for expressions, use tsubst_expr or tsubst_copy. */
14173 tree
14175 {
14198 else
14203 /* Reuse typedefs. We need to do this to handle dependent attributes,
14204 such as attribute aligned. */
14207 {
14211 {
14212 /* DECL represents an alias template and we want to
14213 instantiate it. */
14217 }
14221 {
14225 }
14230 else
14231 /* The typedef is from a non-template context. */
14235 {
14237 r = cp_build_qualified_type_real
14241 }
14242 else
14243 {
14244 /* We don't have an instantiation yet, so drop the typedef. */
14249 }
14250 }
14267 {
14293 {
14299 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
14300 needed. */
14306 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
14307 with TREE_SIDE_EFFECTS that indicates this is not an integral
14308 constant expression. */
14311 {
14314 }
14317 }
14323 {
14329 /* Early in template argument deduction substitution, we don't
14330 want to reduce the level of 'auto', or it will be confused
14331 with a normal template parm in subsequent deduction. */
14343 {
14346 /* See through ARGUMENT_PACK_SELECT arguments. */
14349 }
14354 {
14356 /* If ARG is an argument pack, we don't actually want to
14357 perform a substitution here, because substitutions
14358 for argument packs are only done
14359 element-by-element. We can get to this point when
14360 substituting the type of a non-type template
14361 parameter pack, when that type actually contains
14362 template parameter packs from an outer template, e.g.,
14364 template<typename... Types> struct A {
14365 template<Types... Values> struct B { };
14366 }; */
14370 {
14376 return cp_build_qualified_type_real
14378 }
14380 {
14381 /* We are processing a type constructed from a
14382 template template parameter. */
14393 /* Consider this code:
14395 template <template <class> class Template>
14396 struct Internal {
14397 template <class Arg> using Bind = Template<Arg>;
14398 };
14400 template <template <class> class Template, class Arg>
14401 using Instantiate = Template<Arg>; //#0
14403 template <template <class> class Template,
14404 class Argument>
14405 using Bind =
14406 Instantiate<Internal<Template>::template Bind,
14407 Argument>; //#1
14409 When #1 is parsed, the
14410 BOUND_TEMPLATE_TEMPLATE_PARM representing the
14411 parameter `Template' in #0 matches the
14412 UNBOUND_CLASS_TEMPLATE representing the argument
14413 `Internal<Template>::template Bind'; We then want
14414 to assemble the type `Bind<Argument>' that can't
14415 be fully created right now, because
14416 `Internal<Template>' not being complete, the Bind
14417 template cannot be looked up in that context. So
14418 we need to "store" `Bind<Argument>' for later
14419 when the context of Bind becomes complete. Let's
14420 store that in a TYPENAME_TYPE. */
14424 argvec),
14425 typename_type,
14426 complain);
14428 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
14429 are resolving nested-types in the signature of a
14430 member function templates. Otherwise ARG is a
14431 TEMPLATE_DECL and is the real template to be
14432 instantiated. */
14440 complain);
14441 return cp_build_qualified_type_real
14443 }
14446 else
14447 /* TEMPLATE_PARM_INDEX. */
14449 }
14452 /* This can happen during the attempted tsubst'ing in
14453 unify. This means that we don't yet have any information
14454 about the template parameter in question. */
14457 /* If we get here, we must have been looking at a parm for a
14458 more deeply nested template. Make a new version of this
14459 template parameter, but with a lower level. */
14461 {
14466 {
14468 r = cp_build_qualified_type_real
14472 }
14479 /* Break infinite recursion when substituting the constraints
14481 else
14482 {
14493 {
14494 /* Propagate constraints on placeholders. */
14499 {
14502 }
14503 }
14506 /* We have reduced the level of the template
14507 template parameter, but not the levels of its
14508 template parameters, so canonical_type_parameter
14509 will not be able to find the canonical template
14510 template parameter for this level. Thus, we
14511 require structural equality checking to compare
14512 TEMPLATE_TEMPLATE_PARMs. */
14516 else
14520 {
14522 /* We might need to substitute into the types of non-type
14523 template parameters. */
14535 }
14536 }
14540 /* OK, now substitute the type of the non-type parameter. We
14541 couldn't do it earlier because it might be an auto parameter,
14542 and we wouldn't need to if we had an argument. */
14551 }
14554 }
14557 {
14565 {
14569 }
14572 {
14576 }
14579 {
14583 }
14589 }
14592 /* We should never be tsubsting a binfo. */
14596 /* A vector of template arguments. */
14602 {
14606 /* [temp.deduct]
14608 Type deduction may fail for any of the following
14609 reasons:
14611 -- Attempting to create a pointer to reference type.
14612 -- Attempting to create a reference to a reference type or
14613 a reference to void.
14615 Core issue 106 says that creating a reference to a reference
14616 during instantiation is no longer a cause for failure. We
14617 only enforce this check in strict C++98 mode. */
14621 {
14624 /* We keep track of the last time we issued this error
14625 message to avoid spewing a ton of messages during a
14626 single bad template instantiation. */
14629 {
14634 else
14637 }
14640 }
14644 {
14646 {
14649 type);
14650 else
14652 type);
14653 }
14655 }
14657 {
14661 }
14663 /* In C++0x, during template argument substitution, when there is an
14664 attempt to create a reference to a reference type, reference
14665 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
14667 "If a template-argument for a template-parameter T names a type
14668 that is a reference to a type A, an attempt to create the type
14669 'lvalue reference to cv T' creates the type 'lvalue reference to
14670 A,' while an attempt to create the type type rvalue reference to
14671 cv T' creates the type T"
14672 */
14673 r = cp_build_reference_type
14676 else
14681 /* Will this ever be needed for TYPE_..._TO values? */
14685 }
14687 {
14690 {
14691 /* [temp.deduct]
14693 Type deduction may fail for any of the following
14694 reasons:
14696 -- Attempting to create "pointer to member of T" when T
14697 is not a class type. */
14701 }
14703 {
14707 }
14709 {
14713 }
14716 {
14717 /* The type of the implicit object parameter gets its
14718 cv-qualifiers from the FUNCTION_TYPE. */
14719 tree memptr;
14720 tree method_type
14725 complain);
14726 }
14727 else
14730 complain);
14731 }
14734 {
14735 tree fntype;
14736 tree specs;
14741 /* Substitute the exception specification. */
14749 }
14751 {
14756 /* As an optimization, we avoid regenerating the array type if
14757 it will obviously be the same as T. */
14761 /* These checks should match the ones in create_array_type_for_decl.
14763 [temp.deduct]
14765 The deduction may fail for any of the following reasons:
14767 -- Attempting to create an array with an element type that
14768 is void, a function type, or a reference type, or [DR337]
14769 an abstract class type. */
14775 {
14779 }
14791 {
14794 }
14797 }
14800 {
14812 {
14816 }
14818 {
14819 /* Normally, make_typename_type does not require that the CTX
14820 have complete type in order to allow things like:
14822 template <class T> struct S { typename S<T>::X Y; };
14824 But, such constructs have already been resolved by this
14825 point, so here CTX really should have complete type, unless
14826 it's a partial instantiation. */
14829 {
14833 }
14834 }
14841 {
14844 }
14847 {
14849 {
14853 else
14855 }
14857 {
14861 else
14863 }
14864 }
14866 return cp_build_qualified_type_real
14868 }
14871 {
14883 }
14886 {
14887 tree type;
14903 complain);
14904 }
14907 {
14908 tree type;
14919 {
14921 {
14925 }
14928 }
14939 else
14940 {
14944 /* In a template ~id could be either a complement expression
14945 or an unqualified-id naming a destructor; if instantiating
14946 it produces an expression, it's not an id-expression or
14947 member access. */
14950 }
14955 }
14958 {
14962 }
14966 {
14967 tree r;
14971 else
14979 }
14994 /* We should use one of the expression tsubsts for these codes. */
15000 }
15001 }
15003 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
15004 expression on the left-hand side of the "." or "->" operator. We
15005 only do the lookup if we had a dependent BASELINK. Otherwise we
15006 adjust it onto the instantiated heirarchy. */
15008 static tree
15011 {
15023 {
15030 }
15037 {
15043 /* Treat as-if non-dependent below. */
15048 {
15054 }
15058 }
15059 else
15060 /* We're going to overwrite pieces below, make a duplicate. */
15063 /* If lookup found a single function, mark it as used at this point.
15064 (If lookup found multiple functions the one selected later by
15065 overload resolution will be marked as used at that point.) */
15067 {
15073 /* We might have instantiated an auto function. */
15075 }
15078 {
15079 /* Add back the template arguments, if present. */
15084 /* Update the conversion operator type. */
15086 }
15092 {
15094 qualifying_scope,
15095 object_type);
15097 /* We need to call adjust_result_of_qualified_name_lookup in case the
15098 destructor names a base class, but we unset BASELINK_QUALIFIED_P
15099 so that we still get virtual function binding. */
15101 }
15104 }
15106 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
15107 true if the qualified-id will be a postfix-expression in-and-of
15108 itself; false if more of the postfix-expression follows the
15109 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
15110 of "&". */
15112 static tree
15116 {
15117 tree expr;
15118 tree scope;
15119 tree name;
15121 tree template_args;
15126 /* Figure out what name to look up. */
15129 {
15139 }
15140 else
15141 {
15144 }
15146 /* Substitute into the qualifying scope. When there are no ARGS, we
15147 are just trying to simplify a non-dependent expression. In that
15148 case the qualifying scope may be dependent, and, in any case,
15149 substituting will not help. */
15152 {
15155 }
15156 else
15160 {
15167 }
15170 {
15172 {
15173 /* A BIT_NOT_EXPR is used to represent a destructor. */
15175 {
15179 }
15180 else
15183 }
15184 else
15188 {
15190 {
15194 }
15196 }
15197 }
15200 {
15202 scope);
15203 /* Remember that there was a reference to this entity. */
15206 }
15209 {
15215 }
15218 {
15219 /* We may be repeating a check already done during parsing, but
15220 if it was well-formed and passed then, it will pass again
15221 now, and if it didn't, we wouldn't have got here. The case
15222 we want to catch is when we couldn't tell then, and can now,
15223 namely when templ prior to substitution was an
15224 identifier. */
15230 complain);
15231 else
15233 }
15239 {
15240 expr = (adjust_result_of_qualified_name_lookup
15242 expr = (finish_qualified_id_expr
15246 }
15248 /* Expressions do not generally have reference type. */
15250 /* However, if we're about to form a pointer-to-member, we just
15251 want the referenced member referenced. */
15259 }
15261 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
15262 initializer, DECL is the substituted VAR_DECL. Other arguments are as
15263 for tsubst. */
15265 static tree
15268 {
15275 {
15276 /* If we had an initializer but it
15277 instantiated to nothing,
15278 value-initialize the object. This will
15279 only occur when the initializer was a
15280 pack expansion where the parameter packs
15281 used in that expansion were of length
15282 zero. */
15284 complain);
15289 }
15292 }
15294 /* Like tsubst, but deals with expressions. This function just replaces
15295 template parms; to finish processing the resultant expression, use
15296 tsubst_copy_and_build or tsubst_expr. */
15298 static tree
15300 {
15302 tree r;
15310 {
15315 {
15316 /* We get here for a use of 'this' in an NSDMI. */
15320 /* This can happen for a parameter name used later in a function
15321 declaration (such as in a late-specified return type). Just
15322 make a dummy decl, since it's only used for its type. */
15325 /* Give it the template pattern as its context; its true context
15326 hasn't been instantiated yet and this is good enough for
15327 mangling. */
15329 }
15338 {
15339 tree enum_type;
15340 tree v;
15344 /* There is no need to substitute into namespace-scope
15345 enumerators. */
15348 /* If ARGS is NULL, then T is known to be non-dependent. */
15352 /* Unfortunately, we cannot just call lookup_name here.
15353 Consider:
15355 template <int I> int f() {
15356 enum E { a = I };
15357 struct S { void g() { E e = a; } };
15358 };
15360 When we instantiate f<7>::S::g(), say, lookup_name is not
15361 clever enough to find f<7>::a. */
15362 enum_type
15372 /* We didn't find the name. That should never happen; if
15373 name-lookup found it during preliminary parsing, we
15374 should find it again here during instantiation. */
15376 }
15381 {
15382 tree ctx;
15387 {
15390 {
15394 }
15396 }
15397 }
15407 {
15410 {
15411 /* First try name lookup to find the instantiation. */
15414 {
15415 /* Make sure that the one we found is the one we want. */
15419 }
15423 else
15424 {
15425 /* This can happen for a variable used in a
15426 late-specified return type of a local lambda, or for a
15427 local static or constant. Building a new VAR_DECL
15428 should be OK in all those cases. */
15431 /* Avoid infinite recursion (79640). */
15434 {
15435 /* We can't call cp_finish_decl, so handle the
15436 initializer by hand. */
15451 }
15458 }
15459 /* Remember this for subsequent uses. */
15462 }
15465 }
15466 else
15476 /* An OVERLOAD will always be a non-dependent overload set; an
15477 overload set from function scope will just be represented with an
15478 IDENTIFIER_NODE, and from class scope with a BASELINK. */
15480 /* We must have marked any lookups as persistent. */
15496 {
15497 /* Template template argument like the following example need
15498 special treatment:
15500 template <template <class> class TT> struct C {};
15501 template <class T> struct D {
15502 template <class U> struct E {};
15503 C<E> c; // #1
15504 };
15505 D<int> d; // #2
15507 We are processing the template argument `E' in #1 for
15508 the template instantiation #2. Originally, `E' is a
15509 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
15510 have to substitute this with one having context `D<int>'. */
15514 {
15515 /* When rewriting a constructor into a deduction guide, a
15516 non-dependent name can become dependent, so memtmpl<args>
15517 becomes context::template memtmpl<args>. */
15521 }
15523 }
15524 else
15525 /* Ordinary template template argument. */
15530 {
15531 /* Handle location wrappers by substituting the wrapped node
15532 first, *then* reusing the resulting type. Doing the type
15533 first ensures that we handle template parameters and
15534 parameter pack expansions. */
15538 }
15548 {
15552 }
15557 {
15566 /* We only want to compute the number of arguments. */
15569 else
15576 {
15578 /* Set TREE_USED for the benefit of -Wunused. */
15582 }
15590 {
15595 else
15602 else
15605 }
15606 else
15608 }
15610 {
15618 }
15619 /* Fall through */
15635 {
15642 }
15645 {
15646 tree object;
15647 tree name;
15652 {
15656 }
15659 {
15669 }
15674 in_decl);
15675 else
15678 }
15716 {
15720 }
15723 {
15728 }
15731 {
15735 }
15738 {
15746 }
15752 {
15759 }
15762 {
15769 }
15772 {
15779 }
15782 {
15783 /* Substituted template arguments */
15792 }
15795 {
15815 }
15840 /* Fall through. */
15843 {
15846 }
15847 else
15851 /* This is handled by tsubst_copy_and_build. */
15855 {
15859 }
15862 /* We shouldn't have built any of these during initial template
15863 generation. Instead, they should be built during instantiation
15864 in response to the saved STMT_IS_FULL_EXPR_P setting. */
15868 {
15878 }
15896 {
15897 /* Instantiate any typedefs in the type. */
15902 }
15905 /* These can sometimes show up in a partial instantiation, but never
15906 involve template parms. */
15922 /* ??? There's no point in copying it for now, but maybe some
15923 day it will contain more information, such as a pointer back
15924 to the containing function, inlined copy or so. */
15928 /* We shouldn't get here, but keep going if !flag_checking. */
15932 }
15933 }
15935 /* Helper function for tsubst_omp_clauses, used for instantiation of
15936 OMP_CLAUSE_DECL of clauses. */
15938 static tree
15940 tree in_decl)
15941 {
15945 /* Handle an OpenMP array section represented as a TREE_LIST (or
15946 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15947 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15948 TREE_LIST. We can handle it exactly the same as an array section
15949 (purpose, value, and a chain), even though the nomenclature
15950 (low_bound, length, etc) is different. */
15952 {
15953 tree low_bound
15959 in_decl);
15968 }
15971 /* Undo convert_from_reference tsubst_expr could have called. */
15977 }
15979 /* Like tsubst_copy, but specifically for OpenMP clauses. */
15981 static tree
15984 {
15989 {
15995 {
15998 {
16004 }
16005 /* FALLTHRU */
16020 in_decl);
16052 {
16055 {
16062 }
16063 else
16065 }
16068 in_decl);
16074 in_decl);
16082 in_decl);
16084 {
16087 }
16092 else
16095 in_decl,
16119 }
16122 {
16132 /* tsubst_expr on SCOPE_REF results in returning
16133 finish_non_static_data_member result. Undo that here. */
16137 {
16142 {
16146 CASE_CONVERT:
16155 /* FALLTHRU */
16159 }
16160 }
16166 {
16169 {
16172 }
16173 }
16177 }
16178 }
16182 {
16187 {
16190 }
16191 }
16193 }
16195 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
16197 static tree
16199 tree in_decl)
16200 {
16201 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
16221 {
16224 else
16225 {
16229 }
16230 }
16235 #undef RECUR
16236 }
16238 /* Used to temporarily communicate the list of #pragma omp parallel
16239 clauses to #pragma omp for instantiation if they are combined
16240 together. */
16244 /* Substitute one OMP_FOR iterator. */
16246 static void
16251 {
16252 #define RECUR(NODE) \
16253 tsubst_expr ((NODE), args, complain, in_decl, \
16254 integral_constant_expression_p)
16261 {
16264 }
16270 {
16271 /* We need to jump through some hoops to handle declarations in the
16272 init-statement, since we might need to handle auto deduction,
16273 but we need to keep control of initialization. */
16277 }
16278 else
16279 {
16281 {
16284 {
16288 {
16292 CASE_CONVERT:
16300 {
16303 }
16304 /* FALLTHRU */
16308 }
16309 }
16310 }
16311 else
16313 }
16324 {
16326 {
16327 /* Declare the variable, but don't let that initialize it. */
16332 }
16337 {
16342 }
16343 else
16350 }
16353 {
16354 /* Declare and initialize the variable. */
16357 }
16359 {
16363 {
16365 {
16371 {
16374 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
16379 }
16382 {
16384 decl);
16386 }
16389 {
16391 decl);
16393 }
16394 else
16396 }
16399 }
16401 {
16406 {
16409 }
16410 }
16411 }
16414 {
16418 }
16419 else
16423 {
16434 {
16442 }
16443 else
16449 {
16455 }
16459 {
16467 }
16468 else
16474 }
16480 #undef RECUR
16481 }
16483 /* Helper function of tsubst_expr, find OMP_TEAMS inside
16484 of OMP_TARGET's body. */
16486 static tree
16488 {
16491 {
16500 }
16502 }
16504 /* Helper function for tsubst_expr. For decomposition declaration
16505 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
16506 also the corresponding decls representing the identifiers
16507 of the decomposition declaration. Return DECL if successful
16508 or error_mark_node otherwise, set *FIRST to the first decl
16509 in the list chained through DECL_CHAIN and *CNT to the number
16510 of such decls. */
16512 static tree
16516 {
16521 decl2
16526 {
16528 {
16531 }
16543 else
16544 {
16548 }
16555 {
16558 }
16559 else
16561 }
16564 }
16566 /* Like tsubst_copy for expressions, etc. but also does semantic
16567 processing. */
16569 tree
16572 {
16573 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
16574 #define RECUR(NODE) \
16575 tsubst_expr ((NODE), args, complain, in_decl, \
16576 integral_constant_expression_p)
16579 tree r;
16580 location_t loc;
16592 {
16594 {
16595 tree_stmt_iterator i;
16599 }
16614 else
16624 {
16626 tree init;
16632 {
16642 else
16644 }
16647 {
16648 /* We're in tsubst_lambda_expr, we've already inserted a new
16649 capture proxy, so look it up and register it. */
16650 tree inst;
16652 {
16653 inst = (retrieve_local_specialization
16656 }
16657 else
16658 {
16662 }
16665 }
16668 /* Don't copy the old closure; we'll create a new one in
16669 tsubst_lambda_expr. */
16671 else
16672 {
16676 {
16677 /* By marking the declaration as instantiated, we avoid
16678 trying to instantiate it. Since instantiate_decl can't
16679 handle local variables, and since we've already done
16680 all that needs to be done, that's the right thing to
16681 do. */
16686 /* Anonymous aggregates are a special case. */
16689 {
16692 {
16696 }
16698 }
16704 {
16709 }
16710 else
16711 {
16716 {
16717 /* For __PRETTY_FUNCTION__ we have to adjust the
16718 initializer. */
16722 }
16723 else
16727 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
16732 {
16734 tree first;
16735 tree ndecl
16743 }
16744 else
16746 }
16747 }
16748 }
16751 }
16761 {
16765 }
16770 {
16771 /* Construct another range_for, if this is not a final
16772 substitution (for inside inside a generic lambda of a
16773 template). Otherwise convert to a regular for. */
16775 stmt = (processing_template_decl
16791 {
16795 }
16796 else
16797 {
16803 }
16809 }
16816 {
16820 }
16826 {
16830 }
16845 {
16846 /* We're partially instantiating a generic lambda, but the condition
16847 of the constexpr if is still dependent. Don't substitute into the
16848 branches now, just remember the template arguments. */
16856 }
16859 else
16860 {
16867 }
16873 {
16882 }
16890 else
16898 else
16919 {
16926 }
16930 {
16932 tree label;
16939 }
16945 /* Computed goto's must be tsubst'd into. On the other hand,
16946 non-computed gotos must not be; the identifier in question
16947 will have no binding. */
16949 else
16955 {
16971 }
16976 {
16981 }
16982 else
16983 {
16988 else
16995 else
17001 else
17003 }
17007 {
17011 {
17013 /* Prevent instantiate_decl from trying to instantiate
17014 this variable. We've already done all that needs to be
17015 done. */
17018 }
17023 }
17029 {
17030 /* Local classes are not independent templates; they are
17031 instantiated along with their containing function. And this
17032 way we don't have to deal with pushing out of one local class
17033 to instantiate a member of another local class. */
17034 /* Closures are handled by the LAMBDA_EXPR. */
17044 }
17048 {
17049 tree condition;
17052 condition =
17054 args,
17063 }
17069 in_decl);
17104 {
17117 in_decl);
17119 {
17126 }
17138 integral_constant_expression_p);
17149 else
17150 {
17158 }
17162 }
17167 /* FALLTHRU */
17174 in_decl);
17191 in_decl);
17202 {
17205 {
17206 /* For combined target teams, ensure the num_teams and
17207 thread_limit clause expressions are evaluated on the host,
17208 before entering the target construct. */
17209 tree c;
17215 {
17224 OMP_CLAUSE_FIRSTPRIVATE);
17228 }
17229 }
17230 }
17290 {
17295 {
17298 }
17304 }
17305 else
17306 {
17313 {
17316 }
17319 {
17324 {
17327 }
17333 }
17334 else
17335 {
17339 }
17342 }
17346 {
17352 {
17356 {
17361 }
17365 }
17366 else
17367 {
17372 }
17373 }
17377 {
17381 }
17394 /* If the first operand was a statement, we're done with it. */
17398 complain));
17412 integral_constant_expression_p));
17413 }
17416 out:
17419 #undef RECUR
17420 #undef RETURN
17421 }
17423 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
17424 function. For description of the body see comment above
17425 cp_parser_omp_declare_reduction_exprs. */
17427 static void
17429 {
17435 tree_stmt_iterator tsi;
17446 {
17465 }
17467 {
17487 }
17488 }
17490 /* T is a postfix-expression that is not being used in a function
17491 call. Return the substituted version of T. */
17493 static tree
17495 tsubst_flags_t complain,
17496 tree in_decl)
17497 {
17501 else
17507 }
17509 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
17510 instantiation context. Instantiating a pack expansion containing a lambda
17511 might result in multiple lambdas all based on the same lambda in the
17512 template. */
17514 tree
17516 {
17530 else
17538 {
17550 else
17555 {
17564 }
17565 else
17566 {
17572 }
17573 }
17579 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
17597 else
17598 {
17599 /* Fix the type of 'this'. */
17605 {
17609 }
17610 else
17611 {
17615 }
17617 /* Let finish_function set this. */
17623 else
17624 /* Still increment function_depth so that we don't GC in the
17625 middle of an expression. */
17641 else
17644 /* The capture list was built up in reverse order; fix that now. */
17651 }
17658 }
17660 /* Like tsubst but deals with expressions and performs semantic
17661 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
17663 tree
17665 tree args,
17666 tsubst_flags_t complain,
17667 tree in_decl,
17670 {
17671 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
17672 #define RECUR(NODE) \
17673 tsubst_copy_and_build (NODE, args, complain, in_decl, \
17675 integral_constant_expression_p)
17678 location_t loc;
17687 /* N3276 decltype magic only applies to calls at the top level or on the
17688 right side of a comma. */
17693 {
17696 /* Fall through. */
17698 {
17699 tree decl;
17700 cp_id_kind idk;
17705 {
17708 }
17710 /* Look up the name. */
17713 /* By convention, expressions use ERROR_MARK_NODE to indicate
17714 failure, not NULL_TREE. */
17720 integral_constant_expression_p,
17728 input_location);
17732 {
17736 }
17738 }
17741 {
17742 tree object;
17752 {
17757 }
17763 {
17766 }
17767 else
17774 else
17776 }
17779 {
17783 {
17784 /* A type conversion to reference type will be enclosed in
17785 such an indirect ref, but the substitution of the cast
17786 will have also added such an indirect ref. */
17788 }
17789 else
17797 }
17800 {
17804 }
17807 {
17811 {
17816 }
17818 /* We'll pass this to convert_nontype_argument again, we don't need
17819 to actually perform any conversion here. */
17825 flags));
17826 }
17829 {
17835 }
17842 {
17843 tree type;
17849 {
17854 }
17861 {
17879 }
17882 }
17915 else
17917 in_decl);
17952 {
17959 tree r = build_x_binary_op
17961 op0,
17963 ? ERROR_MARK
17965 op1,
17967 ? ERROR_MARK
17975 }
17978 {
17982 }
17998 /* Fall through */
18001 {
18002 tree r;
18010 {
18011 /* When there are no ARGS, we are trying to evaluate a
18012 non-dependent expression from the parser. Trying to do
18013 the substitutions may not work. */
18016 }
18017 else
18018 {
18023 else
18026 /*integral_constant_expression_p=*/
18030 }
18034 else
18038 {
18040 {
18042 {
18046 }
18047 else
18051 }
18053 }
18055 }
18058 {
18068 }
18084 {
18088 tree r = build_x_modify_expr
18091 /* TREE_NO_WARNING must be set if either the expression was
18092 parenthesized or it uses an operator such as >>= rather
18093 than plain assignment. In the former case, it was already
18094 set and must be copied. In the latter case,
18095 build_x_modify_expr sets it and it must not be reset
18096 here. */
18101 }
18106 /* Remember that there was a reference to this entity. */
18113 {
18118 tree ret;
18122 else
18123 {
18127 }
18129 /* If there was an initializer in the original tree, but it
18130 instantiated to an empty list, then we should pass a
18131 non-NULL empty vector to tell build_new that it was an
18132 empty initializer() rather than no initializer. This can
18133 only happen when the initializer is a pack expansion whose
18134 parameter packs are of length zero. */
18137 else
18138 {
18142 else
18143 {
18146 }
18147 }
18149 /* Avoid passing an enclosing decl to valid_array_size_p. */
18156 complain);
18164 }
18167 {
18173 complain));
18174 }
18177 {
18181 integral_constant_expression_p);
18183 op0,
18186 }
18189 {
18190 tree function;
18195 tree ret;
18198 /* Internal function with no arguments. */
18202 /* When we parsed the expression, we determined whether or
18203 not Koenig lookup should be performed. */
18206 {
18209 }
18211 {
18216 }
18218 {
18219 /* Do nothing; calling tsubst_copy_and_build on an identifier
18220 would incorrectly perform unqualified lookup again.
18222 Note that we can also have an IDENTIFIER_NODE if the earlier
18223 unqualified lookup found a member function; in that case
18224 koenig_p will be false and we do want to do the lookup
18225 again to find the instantiated member function.
18227 FIXME but doing that causes c++/15272, so we need to stop
18228 using IDENTIFIER_NODE in that situation. */
18230 }
18231 else
18232 {
18234 {
18240 }
18241 else
18246 /* Avoid error about taking the address of a constructor. */
18250 in_decl,
18252 integral_constant_expression_p);
18256 }
18261 {
18266 else
18267 {
18268 /* Expand the pack expansion and push each entry onto
18269 CALL_ARGS. */
18272 {
18277 {
18282 }
18283 }
18284 else
18285 {
18286 /* A partial substitution. Add one entry. */
18288 }
18289 }
18290 }
18292 /* We do not perform argument-dependent lookup if normal
18293 lookup finds a non-function, in accordance with the
18294 expected resolution of DR 218. */
18297 /* If lookup found a member function, the Koenig lookup is
18298 not appropriate, even if an unqualified-name was used
18299 to denote the function. */
18302 /* Only do this when substitution turns a dependent call
18303 into a non-dependent call. */
18311 {
18313 {
18314 /* For backwards compatibility and good diagnostics, try
18315 the unqualified lookup again if we aren't in SFINAE
18316 context. */
18317 tree unq = (tsubst_copy_and_build
18319 integral_constant_expression_p));
18321 {
18324 }
18327 {
18328 /* In a lambda fn, we have to be careful to not
18329 introduce new this captures. Legacy code can't
18330 be using lambdas anyway, so it's ok to be
18331 stricter. */
18336 "and no declarations were found by "
18337 "argument-dependent lookup at the point "
18344 else
18348 {
18359 {
18361 input_location);
18363 "declarations in dependent base %qT are "
18369 else
18373 }
18374 else
18376 "%qD declared here, later in the "
18379 {
18382 }
18383 }
18386 }
18387 }
18389 {
18394 }
18395 }
18397 /* Remember that there was a reference to this entity. */
18401 {
18404 }
18406 /* Put back tf_decltype for the actual call. */
18411 {
18415 {
18417 "wrong number of arguments to "
18420 }
18421 else
18423 input_location),
18428 /* Unsupported internal function with arguments. */
18430 }
18433 complain);
18435 {
18450 complain);
18451 else
18452 ret = (build_new_method_call
18457 complain));
18458 }
18459 else
18462 koenig_p,
18463 complain);
18468 {
18474 {
18480 {
18483 else
18485 /* The thunk location is not interesting. */
18487 }
18488 }
18489 }
18492 }
18495 {
18501 {
18503 {
18508 }
18509 else
18510 {
18515 }
18517 }
18518 else
18519 {
18522 }
18527 }
18530 {
18535 input_location));
18536 }
18539 {
18547 {
18548 /* We have pack expansions, so expand those and
18549 create a new list out of it. */
18552 tree chain;
18555 /* Expand the argument expressions. */
18563 /* Build the rest of the list. */
18568 /* Determine the number of arguments. */
18570 {
18573 }
18576 else
18577 {
18578 /* Since we only performed a partial substitution into
18579 the argument pack, we only RETURN (a single list
18580 node. */
18587 }
18589 /* Convert the argument vectors into a TREE_LIST */
18592 {
18593 /* Grab the Ith values. */
18594 i--;
18597 value
18601 /* Build the list (backwards). */
18603 }
18606 }
18622 }
18625 {
18626 tree object;
18627 tree object_type;
18628 tree member;
18629 tree r;
18633 /* Remember that there was a reference to this entity. */
18644 else
18650 {
18655 }
18659 {
18661 {
18666 {
18669 }
18671 {
18676 }
18677 }
18678 }
18681 {
18682 /* Lookup the template functions now that we know what the
18683 scope is. */
18691 {
18694 args);
18695 member = (adjust_result_of_qualified_name_lookup
18697 object_type));
18698 }
18699 else
18700 {
18702 input_location);
18704 }
18705 }
18709 {
18711 {
18715 else
18718 }
18720 }
18724 complain);
18728 }
18735 {
18743 tree r;
18748 /* We do not want to process the index of aggregate
18749 initializers as they are identifier nodes which will be
18750 looked up by digest_init. */
18756 {
18758 /* An identifier index is looked up in the type
18759 being initialized, not the current scope. */
18764 {
18765 /* Substitute into the pack expansion. */
18767 in_decl);
18771 ;
18773 /* Just move the argument into place. */
18775 else
18776 {
18777 /* Update the length of the final CONSTRUCTOR
18778 arguments vector, and note that we will need to
18779 copy.*/
18782 }
18783 }
18784 else
18786 }
18789 {
18794 {
18796 {
18801 }
18802 else
18804 }
18805 }
18811 {
18816 }
18820 }
18823 {
18826 {
18829 }
18830 else
18831 {
18834 }
18835 }
18840 /* Fall through */
18843 {
18845 /* ??? We're doing a subset of finish_id_expression here. */
18847 && !processing_template_decl
18848 && !cp_unevaluated_operand
18851 {
18853 /* Replace an evaluated use of the thread_local variable with
18854 a call to its wrapper. */
18856 }
18861 /* If the original type was a reference, we'll be wrapped in
18862 the appropriate INDIRECT_REF. */
18865 }
18868 {
18872 }
18875 {
18876 tree object_ptr
18883 }
18890 {
18901 }
18904 {
18910 integral_constant_expression_p);
18914 /* If the resulting list of expression statement is empty,
18915 fold it further into void_node. */
18920 }
18923 {
18927 }
18930 /* We can get here for a constant initializer of non-dependent type.
18931 FIXME stop folding in cp_parser_initializer_clause. */
18932 {
18934 complain);
18936 }
18940 integral_constant_expression_p));
18946 {
18951 complain));
18952 }
18959 /* We should only see these for location wrapper nodes, or within
18960 instantiate_non_dependent_expr (when args is NULL_TREE). */
18965 /* fallthrough. */
18968 /* Handle Objective-C++ constructs, if appropriate. */
18969 {
18970 tree subst
18975 }
18977 }
18979 #undef RECUR
18980 #undef RETURN
18981 out:
18984 }
18986 /* Verify that the instantiated ARGS are valid. For type arguments,
18987 make sure that the type's linkage is ok. For non-type arguments,
18988 make sure they are constants if they are integral or enumerations.
18989 Emit an error under control of COMPLAIN, and return TRUE on error. */
18991 static bool
18993 {
18997 {
19007 }
19009 {
19010 /* [basic.link]: A name with no linkage (notably, the name
19011 of a class or enumeration declared in a local scope)
19012 shall not be used to declare an entity with linkage.
19013 This implies that names with no linkage cannot be used as
19014 template arguments
19016 DR 757 relaxes this restriction for C++0x. */
19021 {
19022 /* DR 488 makes use of a type with no linkage cause
19023 type deduction to fail. */
19025 {
19028 else
19031 }
19033 }
19034 /* In order to avoid all sorts of complications, we do not
19035 allow variably-modified types as template arguments. */
19037 {
19041 }
19042 }
19043 /* Class template and alias template arguments should be OK. */
19045 ;
19046 /* A non-type argument of integral or enumerated type must be a
19047 constant. */
19052 {
19056 }
19058 }
19060 static bool
19062 {
19067 {
19070 }
19074 }
19076 /* We're out of SFINAE context now, so generate diagnostics for the access
19077 errors we saw earlier when instantiating D from TMPL and ARGS. */
19079 static void
19081 {
19093 }
19095 /* Instantiate the indicated variable, function, or alias template TMPL with
19096 the template arguments in TARG_PTR. */
19098 static tree
19100 {
19102 tree fndecl;
19103 tree gen_tmpl;
19104 tree spec;
19112 /* If this function is a clone, handle it specially. */
19114 {
19115 tree spec;
19116 tree clone;
19118 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
19119 DECL_CLONED_FUNCTION. */
19125 /* Look for the clone. */
19129 /* We should always have found the clone by now. */
19132 }
19137 /* Check to see if we already have this specialization. */
19141 /* targ_ptr only has the innermost template args, so add the outer ones
19142 from tmpl, which could be either a partial instantiation or gen_tmpl (in
19143 the case of a non-dependent call within a template definition). */
19144 targ_ptr = (add_outermost_template_args
19146 targ_ptr));
19148 /* It would be nice to avoid hashing here and then again in tsubst_decl,
19149 but it doesn't seem to be on the hot path. */
19158 {
19160 {
19164 }
19166 }
19169 complain))
19172 /* We are building a FUNCTION_DECL, during which the access of its
19173 parameters and return types have to be checked. However this
19174 FUNCTION_DECL which is the desired context for access checking
19175 is not built yet. We solve this chicken-and-egg problem by
19176 deferring all checks until we have the FUNCTION_DECL. */
19179 /* Instantiation of the function happens in the context of the function
19180 template, not the context of the overload resolution we're doing. */
19182 /* If there are dependent arguments, e.g. because we're doing partial
19183 ordering, make sure processing_template_decl stays set. */
19187 {
19191 }
19197 {
19198 /* We need to determine if we're using a partial or explicit
19199 specialization now, because the type of the variable could be
19200 different. */
19206 {
19211 }
19212 }
19214 /* Substitute template parameters to obtain the specialization. */
19222 {
19225 }
19227 /* The DECL_TI_TEMPLATE should always be the immediate parent
19228 template, not the most general template. */
19232 /* Now we know the specialization, compute access previously
19233 deferred. Do no access control for inheriting constructors,
19234 as we already checked access for the inherited constructor. */
19237 {
19242 }
19245 /* If we've just instantiated the main entry point for a function,
19246 instantiate all the alternate entry points as well. We do this
19247 by cloning the instantiation of the main entry point, not by
19248 instantiating the template clones. */
19253 {
19255 {
19256 /* Remember to reinstantiate when we're out of SFINAE so the user
19257 can see the errors. */
19259 }
19261 }
19263 }
19265 /* Wrapper for instantiate_template_1. */
19267 tree
19269 {
19270 tree ret;
19275 }
19277 /* Instantiate the alias template TMPL with ARGS. Also push a template
19278 instantiation level, which instantiate_template doesn't do because
19279 functions and variables have sufficient context established by the
19280 callers. */
19282 static tree
19284 {
19290 args =
19300 }
19302 /* PARM is a template parameter pack for FN. Returns true iff
19303 PARM is used in a deducible way in the argument list of FN. */
19305 static bool
19307 {
19310 {
19312 tree packs;
19318 {
19319 /* The template parameter pack is used in a function parameter
19320 pack. If this is the end of the parameter list, the
19321 template parameter pack is deducible. */
19324 else
19325 /* Otherwise, not. Well, it could be deduced from
19326 a non-pack parameter, but doing so would end up with
19327 a deduction mismatch, so don't bother. */
19329 }
19330 }
19331 /* The template parameter pack isn't used in any function parameter
19332 packs, but it might be used deeper, e.g. tuple<Args...>. */
19334 }
19336 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
19337 NARGS elements of the arguments that are being used when calling
19338 it. TARGS is a vector into which the deduced template arguments
19339 are placed.
19341 Returns either a FUNCTION_DECL for the matching specialization of FN or
19342 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
19343 true, diagnostics will be printed to explain why it failed.
19345 If FN is a conversion operator, or we are trying to produce a specific
19346 specialization, RETURN_TYPE is the return type desired.
19348 The EXPLICIT_TARGS are explicit template arguments provided via a
19349 template-id.
19351 The parameter STRICT is one of:
19353 DEDUCE_CALL:
19354 We are deducing arguments for a function call, as in
19355 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
19356 deducing arguments for a call to the result of a conversion
19357 function template, as in [over.call.object].
19359 DEDUCE_CONV:
19360 We are deducing arguments for a conversion function, as in
19361 [temp.deduct.conv].
19363 DEDUCE_EXACT:
19364 We are deducing arguments when doing an explicit instantiation
19365 as in [temp.explicit], when determining an explicit specialization
19366 as in [temp.expl.spec], or when taking the address of a function
19367 template, as in [temp.deduct.funcaddr]. */
19369 tree
19371 tree explicit_targs,
19372 tree targs,
19375 tree return_type,
19376 unification_kind_t strict,
19380 {
19381 tree parms;
19382 tree fntype;
19398 full_targs = (add_outermost_template_args
19400 targs));
19405 /* In C++0x, it's possible to have a function template whose type depends
19406 on itself recursively. This is most obvious with decltype, but can also
19407 occur with enumeration scope (c++/48969). So we need to catch infinite
19408 recursion and reject the substitution at deduction time; this function
19409 will return error_mark_node for any repeated substitution.
19411 This also catches excessive recursion such as when f<N> depends on
19412 f<N-1> across all integers, and returns error_mark_node for all the
19413 substitutions back up to the initial one.
19415 This is, of course, not reentrant. */
19424 {
19425 /* [temp.deduct]
19427 The specified template arguments must match the template
19428 parameters in kind (i.e., type, nontype, template), and there
19429 must not be more arguments than there are parameters;
19430 otherwise type deduction fails.
19432 Nontype arguments must match the types of the corresponding
19433 nontype template parameters, or must be convertible to the
19434 types of the corresponding nontype parameters as specified in
19435 _temp.arg.nontype_, otherwise type deduction fails.
19437 All references in the function type of the function template
19438 to the corresponding template parameters are replaced by the
19439 specified template argument values. If a substitution in a
19440 template parameter or in the function type of the function
19441 template results in an invalid type, type deduction fails. */
19452 explicit_targs);
19454 /* Adjust any explicit template arguments before entering the
19455 substitution context. */
19456 explicit_targs
19458 complain,
19464 /* Substitute the explicit args into the function type. This is
19465 necessary so that, for instance, explicitly declared function
19466 arguments can match null pointed constants. If we were given
19467 an incomplete set of explicit args, we must not do semantic
19468 processing during substitution as we could create partial
19469 instantiations. */
19471 {
19476 /* Dig out the actual parm. */
19479 {
19482 }
19484 {
19487 }
19490 /* No explicit argument for this template parameter. */
19494 {
19495 /* Mark the argument pack as "incomplete". We could
19496 still deduce more arguments during unification.
19497 We remove this mark in type_unification_real. */
19499 {
19503 }
19505 /* We have some incomplete argument packs. */
19507 }
19508 }
19511 {
19514 }
19517 /* Ignore any access checks; we'll see them again in
19518 instantiate_template and they might have the wrong
19519 access path at this point. */
19531 /* Place the explicitly specified arguments in TARGS. */
19535 }
19537 /* Never do unification on the 'this' parameter. */
19541 {
19542 /* We're deducing for a call to the result of a template conversion
19543 function. The parms we really want are in return_type. */
19547 }
19549 {
19558 }
19560 /* We allow incomplete unification without an error message here
19561 because the standard doesn't seem to explicitly prohibit it. Our
19562 callers must be ready to deal with unification failures in any
19563 event. */
19565 /* If we aren't explaining yet, push tinst context so we can see where
19566 any errors (e.g. from class instantiations triggered by instantiation
19567 of default template arguments) come from. If we are explaining, this
19568 context is redundant. */
19570 {
19573 }
19575 /* type_unification_real will pass back any access checks from default
19576 template argument substitution. */
19588 /* Now that we have bindings for all of the template arguments,
19589 ensure that the arguments deduced for the template template
19590 parameters have compatible template parameter lists. We cannot
19591 check this property before we have deduced all template
19592 arguments, because the template parameter types of a template
19593 template parameter might depend on prior template parameters
19594 deduced after the template template parameter. The following
19595 ill-formed example illustrates this issue:
19597 template<typename T, template<T> class C> void f(C<5>, T);
19599 template<int N> struct X {};
19601 void g() {
19602 f(X<5>(), 5l); // error: template argument deduction fails
19603 }
19605 The template parameter list of 'C' depends on the template type
19606 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
19607 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
19608 time that we deduce 'C'. */
19611 {
19614 }
19616 /* All is well so far. Now, check:
19618 [temp.deduct]
19620 When all template arguments have been deduced, all uses of
19621 template parameters in nondeduced contexts are replaced with
19622 the corresponding deduced argument values. If the
19623 substitution results in an invalid type, as described above,
19624 type deduction fails. */
19626 {
19629 }
19631 /* Also collect access checks from the instantiation. */
19644 /* Now perform any access checks encountered during substitution. */
19651 /* If we're looking for an exact match, check that what we got
19652 is indeed an exact match. It might not be if some template
19653 parameters are used in non-deduced contexts. But don't check
19654 for an exact match if we have dependent template arguments;
19655 in that case we're doing partial ordering, and we already know
19656 that we have two candidates that will provide the actual type. */
19658 {
19662 tree sarg
19668 {
19672 }
19673 }
19675 /* After doing deduction with the inherited constructor, actually return an
19676 instantiation of the inheriting constructor. */
19682 fail:
19685 {
19687 /* Reset once we're all the way out. */
19689 }
19692 }
19694 /* Adjust types before performing type deduction, as described in
19695 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
19696 sections are symmetric. PARM is the type of a function parameter
19697 or the return type of the conversion function. ARG is the type of
19698 the argument passed to the call, or the type of the value
19699 initialized with the result of the conversion function.
19700 ARG_EXPR is the original argument expression, which may be null. */
19702 static int
19706 tree arg_expr)
19707 {
19711 {
19716 /* Swap PARM and ARG throughout the remainder of this
19717 function; the handling is precisely symmetric since PARM
19718 will initialize ARG rather than vice versa. */
19723 /* Core issue #873: Do the DR606 thing (see below) for these cases,
19724 too, but here handle it by stripping the reference from PARM
19725 rather than by adding it to ARG. */
19733 /* Nothing else to do in this case. */
19738 }
19741 {
19742 /* [temp.deduct.call]
19744 If P is not a reference type:
19746 --If A is an array type, the pointer type produced by the
19747 array-to-pointer standard conversion (_conv.array_) is
19748 used in place of A for type deduction; otherwise,
19750 --If A is a function type, the pointer type produced by
19751 the function-to-pointer standard conversion
19752 (_conv.func_) is used in place of A for type deduction;
19753 otherwise,
19755 --If A is a cv-qualified type, the top level
19756 cv-qualifiers of A's type are ignored for type
19757 deduction. */
19762 else
19764 }
19766 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
19767 reference to a cv-unqualified template parameter that does not represent a
19768 template parameter of a class template (during class template argument
19769 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
19770 an lvalue, the type "lvalue reference to A" is used in place of A for type
19771 deduction. */
19778 /* try_one_overload doesn't provide an arg_expr, but
19779 functions are always lvalues. */
19783 /* [temp.deduct.call]
19785 If P is a cv-qualified type, the top level cv-qualifiers
19786 of P's type are ignored for type deduction. If P is a
19787 reference type, the type referred to by P is used for
19788 type deduction. */
19791 {
19794 }
19796 /* DR 322. For conversion deduction, remove a reference type on parm
19797 too (which has been swapped into ARG). */
19802 }
19804 /* Subroutine of unify_one_argument. PARM is a function parameter of a
19805 template which does contain any deducible template parameters; check if
19806 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
19807 unify_one_argument. */
19809 static int
19812 {
19813 tree type;
19817 else
19824 {
19828 }
19830 {
19835 }
19839 else
19841 }
19845 /* Returns true iff the expression EXPR is one from which a template
19846 argument can be deduced. In other words, if it's an undecorated
19847 use of a template non-type parameter. */
19849 static bool
19851 {
19852 /* Strip implicit conversions. */
19856 }
19858 /* Returns true iff the array domain DOMAIN uses a template parameter in a
19859 deducible way; that is, if it has a max value of <PARM> - 1. */
19861 static bool
19863 {
19872 }
19874 /* Returns true iff the template arguments ARGS use a template parameter
19875 in a deducible way. */
19877 static bool
19879 {
19881 {
19886 else
19887 {
19894 else
19896 }
19899 }
19901 }
19903 /* Returns true iff TYPE contains any deducible references to template
19904 parameters, as per 14.8.2.5. */
19906 static bool
19908 {
19912 /* T
19913 cv-list T
19914 TT<T>
19915 TT<i>
19916 TT<> */
19921 /* T*
19922 T&
19923 T&& */
19927 /* T[integer-constant ]
19928 type [i] */
19933 /* T type ::*
19934 type T::*
19935 T T::*
19936 T (type ::*)()
19937 type (T::*)()
19938 type (type ::*)(T)
19939 type (T::*)(T)
19940 T (type ::*)(T)
19941 T (T::*)()
19942 T (T::*)(T) */
19945 || (uses_deducible_template_parms
19948 /* template-name <T> (where template-name refers to a class template)
19949 template-name <i> (where template-name refers to a class template) */
19956 /* type (T)
19957 T()
19958 T(T) */
19961 {
19970 }
19973 }
19975 /* Subroutine of type_unification_real and unify_pack_expansion to
19976 handle unification of a single P/A pair. Parameters are as
19977 for those functions. */
19979 static int
19983 {
19990 /* We can't deduce anything from this, but we might get all the
19991 template args from other function args. */
19994 /* Implicit conversions (Clause 4) will be performed on a function
19995 argument to convert it to the type of the corresponding function
19996 parameter if the parameter type contains no template-parameters that
19997 participate in template argument deduction. */
20000 /* For function parameters with no deducible template parameters,
20001 just return. We'll check non-dependent conversions later. */
20005 {
20007 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
20008 | UNIFY_ALLOW_MORE_CV_QUAL
20022 }
20024 /* We only do these transformations if this is the top-level
20025 parameter_type_list in a call or declaration matching; in other
20026 situations (nested function declarators, template argument lists) we
20027 won't be comparing a type to an expression, and we don't do any type
20028 adjustments. */
20030 {
20032 {
20035 {
20036 /* [temp.deduct.type] A template-argument can be
20037 deduced from a pointer to function or pointer
20038 to member function argument if the set of
20039 overloaded functions does not contain function
20040 templates and at most one of a set of
20041 overloaded functions provides a unique
20042 match. */
20046 /* If a unique match was not found, this is a
20047 non-deduced context, so we still succeed. */
20049 }
20055 }
20057 arg_strict |=
20059 }
20060 else
20065 /* For deduction from an init-list we need the actual list. */
20069 }
20071 /* for_each_template_parm callback that always returns 0. */
20073 static int
20075 {
20077 }
20079 /* for_each_template_parm any_fn callback to handle deduction of a template
20080 type argument from the type of an array bound. */
20082 static int
20084 {
20092 {
20098 }
20100 /* Keep walking. */
20102 }
20104 /* Try to deduce any not-yet-deduced template type arguments from the type of
20105 an array bound. This is handled separately from unify because 14.8.2.5 says
20106 "The type of a type parameter is only deduced from an array bound if it is
20107 not otherwise deduced." */
20109 static void
20111 {
20116 }
20118 /* Most parms like fn_type_unification.
20120 If SUBR is 1, we're being called recursively (to unify the
20121 arguments of a function or method parameter of a function
20122 template).
20124 CHECKS is a pointer to a vector of access checks encountered while
20125 substituting default template arguments. */
20127 static int
20129 tree full_targs,
20130 tree xparms,
20134 unification_kind_t strict,
20138 {
20143 tree parms;
20154 /* Reset the number of non-defaulted template arguments contained
20155 in TARGS. */
20158 again:
20166 {
20171 /* For a function parameter pack that occurs at the end of the
20172 parameter-declaration-list, the type A of each remaining
20173 argument of the call is compared with the type P of the
20174 declarator-id of the function parameter pack. */
20180 /* For a function parameter pack that does not occur at the
20181 end of the parameter-declaration-list, the type of the
20182 parameter pack is a non-deduced context. */
20189 explain_p))
20191 }
20196 {
20197 /* Unify the remaining arguments with the pack expansion type. */
20198 tree argvec;
20201 /* Allocate a TREE_VEC and copy in all of the arguments */
20206 /* Copy the parameter into parmvec. */
20212 /* Advance to the end of the list of parameters. */
20214 }
20216 /* Fail if we've reached the end of the parm list, and more args
20217 are present, and the parm list isn't variadic. */
20220 /* Fail if parms are left and they don't have default values and
20221 they aren't all deduced as empty packs (c++/57397). This is
20222 consistent with sufficient_parms_p. */
20225 {
20229 do
20230 {
20233 count++;
20235 }
20239 type_pack_p);
20240 }
20243 {
20244 tsubst_flags_t complain = (explain_p
20245 ? tf_warning_or_error
20250 {
20254 /* Clear the "incomplete" flags on all argument packs now so that
20255 substituting them into later default arguments works. */
20257 {
20260 }
20268 {
20273 }
20275 /* If this is an undeduced nontype parameter that depends on
20276 a type parameter, try another pass; its type may have been
20277 deduced from a later argument than the one from which
20278 this parameter can be deduced. */
20282 {
20285 }
20287 /* Core issue #226 (C++0x) [temp.deduct]:
20289 If a template argument has not been deduced, its
20290 default template argument, if any, is used.
20292 When we are in C++98 mode, TREE_PURPOSE will either
20293 be NULL_TREE or ERROR_MARK_NODE, so we do not need
20294 to explicitly check cxx_dialect here. */
20296 /* OK, there is a default argument. Wait until after the
20297 conversion check to do substitution. */
20300 /* If the type parameter is a parameter pack, then it will
20301 be deduced to an empty parameter pack. */
20303 {
20304 tree arg;
20307 {
20310 }
20311 else
20318 }
20321 }
20323 /* DR 1391: All parameters have args, now check non-dependent parms for
20324 convertibility. */
20328 {
20334 /* For a function parameter pack that occurs at the end of the
20335 parameter-declaration-list, the type A of each remaining
20336 argument of the call is compared with the type P of the
20337 declarator-id of the function parameter pack. */
20343 /* For a function parameter pack that does not occur at the
20344 end of the parameter-declaration-list, the type of the
20345 parameter pack is a non-deduced context. */
20354 explain_p))
20356 }
20358 /* Now substitute into the default template arguments. */
20360 {
20378 {
20379 /* The type of this non-type parameter depends on undeduced
20380 parameters. Don't try to use its default argument yet,
20381 but do check whether the arguments we already have cause
20382 substitution failure, so that that happens before we try
20383 later default arguments (78489). */
20385 NULL_TREE);
20388 else
20390 }
20391 else
20392 {
20400 else
20402 }
20413 {
20415 /* The position of the first default template argument,
20416 is also the number of non-defaulted arguments in TARGS.
20417 Record that. */
20420 }
20421 }
20425 }
20431 }
20433 /* Subroutine of type_unification_real. Args are like the variables
20434 at the call site. ARG is an overloaded function (or template-id);
20435 we try deducing template args from each of the overloads, and if
20436 only one succeeds, we go with that. Modifies TARGS and returns
20437 true on success. */
20439 static bool
20441 tree targs,
20442 tree parm,
20443 tree arg,
20444 unification_kind_t strict,
20447 {
20454 {
20457 }
20458 else
20462 /* Handle `&x' where `x' is some static or non-static member
20463 function name. */
20469 /* Strip baselink information. */
20474 {
20475 /* If we got some explicit template args, we need to plug them into
20476 the affected templates before we try to unify, in case the
20477 explicit args will completely resolve the templates in question. */
20484 {
20497 {
20502 {
20505 }
20506 }
20509 }
20510 /* If no templates (or more than one) are fully resolved by the
20511 explicit arguments, this template-id is a non-deduced context; it
20512 could still be OK if we deduce all template arguments for the
20513 enclosing call through other arguments. */
20516 }
20519 /* If ARG is, for example, "(0, &f)" then its type will be unknown
20520 -- but the deduction does not succeed because the expression is
20521 not just the function on its own. */
20523 else
20525 {
20530 {
20533 }
20534 }
20536 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20537 to function or pointer to member function argument if the set of
20538 overloaded functions does not contain function templates and at most
20539 one of a set of overloaded functions provides a unique match.
20541 So if we found multiple possibilities, we return success but don't
20542 deduce anything. */
20545 {
20549 {
20554 /* Don't forget explicit template arguments in a pack. */
20558 }
20559 }
20564 }
20566 /* Core DR 115: In contexts where deduction is done and fails, or in
20567 contexts where deduction is not done, if a template argument list is
20568 specified and it, along with any default template arguments, identifies
20569 a single function template specialization, then the template-id is an
20570 lvalue for the function template specialization. */
20572 tree
20574 {
20587 {
20590 }
20592 {
20595 }
20597 {
20600 }
20603 {
20607 /* If we got some explicit template args, we need to plug them into
20608 the affected templates before we try to unify, in case the
20609 explicit args will completely resolve the templates in question. */
20617 {
20630 {
20633 {
20636 }
20638 {
20641 }
20642 }
20643 }
20645 {
20653 {
20654 tree base
20657 }
20661 }
20663 /* There were no good options and at least one bad one, so let the
20664 user know what the problem is. */
20666 }
20668 }
20670 /* Subroutine of resolve_overloaded_unification; does deduction for a single
20671 overload. Fills TARGS with any deduced arguments, or error_mark_node if
20672 different overloads deduce different arguments for a given parm.
20673 ADDR_P is true if the expression for which deduction is being
20674 performed was of the form "& fn" rather than simply "fn".
20676 Returns 1 on success. */
20678 static int
20680 tree orig_targs,
20681 tree targs,
20682 tree parm,
20683 tree arg,
20684 unification_kind_t strict,
20688 {
20690 tree tempargs;
20696 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20697 to function or pointer to member function argument if the set of
20698 overloaded functions does not contain function templates and at most
20699 one of a set of overloaded functions provides a unique match.
20701 So if this is a template, just return success. */
20713 /* We don't copy orig_targs for this because if we have already deduced
20714 some template args from previous args, unify would complain when we
20715 try to deduce a template parameter for the same argument, even though
20716 there isn't really a conflict. */
20723 /* First make sure we didn't deduce anything that conflicts with
20724 explicitly specified args. */
20726 {
20733 /* Since we're unifying against ourselves, we will fill in
20734 template args used in the function parm list with our own
20735 template parms. Discard them. */
20738 {
20739 /* Check that the argument at each index of the deduced argument pack
20740 is equivalent to the corresponding explicitly specified argument.
20741 We may have deduced more arguments than were explicitly specified,
20742 and that's OK. */
20744 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
20745 that's wrong if we deduce the same argument pack from multiple
20746 function arguments: it's only incomplete the first time. */
20759 }
20762 }
20765 {
20770 }
20773 }
20775 /* PARM is a template class (perhaps with unbound template
20776 parameters). ARG is a fully instantiated type. If ARG can be
20777 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
20778 TARGS are as for unify. */
20780 static tree
20783 {
20784 tree copy_of_targs;
20794 /* We need to make a new template argument vector for the call to
20795 unify. If we used TARGS, we'd clutter it up with the result of
20796 the attempted unification, even if this class didn't work out.
20797 We also don't want to commit ourselves to all the unifications
20798 we've already done, since unification is supposed to be done on
20799 an argument-by-argument basis. In other words, consider the
20800 following pathological case:
20802 template <int I, int J, int K>
20803 struct S {};
20805 template <int I, int J>
20806 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
20808 template <int I, int J, int K>
20809 void f(S<I, J, K>, S<I, I, I>);
20811 void g() {
20812 S<0, 0, 0> s0;
20813 S<0, 1, 2> s2;
20815 f(s0, s2);
20816 }
20818 Now, by the time we consider the unification involving `s2', we
20819 already know that we must have `f<0, 0, 0>'. But, even though
20820 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
20821 because there are two ways to unify base classes of S<0, 1, 2>
20822 with S<I, I, I>. If we kept the already deduced knowledge, we
20823 would reject the possibility I=1. */
20827 {
20831 }
20833 /* If unification failed, we're done. */
20839 }
20841 /* Given a template type PARM and a class type ARG, find the unique
20842 base type in ARG that is an instance of PARM. We do not examine
20843 ARG itself; only its base-classes. If there is not exactly one
20844 appropriate base class, return NULL_TREE. PARM may be the type of
20845 a partial specialization, as well as a plain template type. Used
20846 by unify. */
20848 static enum template_base_result
20851 {
20853 tree binfo;
20859 {
20860 /* The type could not be completed. */
20863 }
20865 /* Walk in inheritance graph order. The search order is not
20866 important, and this avoids multiple walks of virtual bases. */
20868 {
20873 {
20874 /* If there is more than one satisfactory baseclass, then:
20876 [temp.deduct.call]
20878 If they yield more than one possible deduced A, the type
20879 deduction fails.
20881 applies. */
20883 {
20886 }
20889 }
20890 }
20894 }
20896 /* Returns the level of DECL, which declares a template parameter. */
20898 static int
20900 {
20902 {
20912 }
20914 }
20916 /* Decide whether ARG can be unified with PARM, considering only the
20917 cv-qualifiers of each type, given STRICT as documented for unify.
20918 Returns nonzero iff the unification is OK on that basis. */
20920 static int
20922 {
20928 {
20929 /* Although a CVR qualifier is ignored when being applied to a
20930 substituted template parameter ([8.3.2]/1 for example), that
20931 does not allow us to unify "const T" with "int&" because both
20932 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
20933 It is ok when we're allowing additional CV qualifiers
20934 at the outer level [14.8.2.1]/3,1st bullet. */
20944 }
20955 }
20957 /* Determines the LEVEL and INDEX for the template parameter PARM. */
20958 void
20960 {
20964 {
20967 }
20968 else
20969 {
20972 }
20973 }
20975 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
20976 do { \
20977 if (unify (TP, TA, P, A, S, EP)) \
20978 return 1; \
20979 } while (0)
20981 /* Unifies the remaining arguments in PACKED_ARGS with the pack
20982 expansion at the end of PACKED_PARMS. Returns 0 if the type
20983 deduction succeeds, 1 otherwise. STRICT is the same as in
20984 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
20985 function call argument list. We'll need to adjust the arguments to make them
20986 types. SUBR tells us if this is from a recursive call to
20987 type_unification_real, or for comparing two template argument
20988 lists. */
20990 static int
20994 {
20995 tree parm
21001 /* Add in any args remembered from an earlier partial instantiation. */
21009 /* Determine the parameter packs we will be deducing from the
21010 pattern, and record their current deductions. */
21013 {
21017 /* Only template parameter packs can be deduced, not e.g. function
21018 parameter packs or __bases or __integer_pack. */
21022 /* Determine the index and level of this parameter pack. */
21027 /* Keep track of the parameter packs and their corresponding
21028 argument packs. */
21031 }
21033 /* Loop through all of the arguments that have not yet been
21034 unified and unify each with the pattern. */
21036 {
21037 tree parm;
21041 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
21042 or the element of its argument pack at the current index if
21043 this argument was explicitly specified. */
21045 {
21054 {
21057 }
21059 }
21061 /* If we had explicit template arguments, substitute them into the
21062 pattern before deduction. */
21064 {
21065 /* Some arguments might still be unspecified or dependent. */
21073 NULL_TREE);
21078 }
21079 else
21082 /* Unify the pattern with the current argument. */
21084 explain_p))
21087 /* For each parameter pack, collect the deduced value. */
21089 {
21095 }
21096 }
21098 /* Verify that the results of unification with the parameter packs
21099 produce results consistent with what we've seen before, and make
21100 the deduced argument packs available. */
21102 {
21109 /* By default keep the original deduced argument pack.
21110 If necessary, more specific code is going to update the
21111 resulting deduced argument later down in this function. */
21115 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
21116 actually deduce anything. */
21124 {
21125 /* If we had fewer function args than explicit template args,
21126 just use the explicits. */
21131 }
21134 {
21135 tree result;
21136 /* Build the deduced *_ARGUMENT_PACK. */
21138 {
21141 }
21142 else
21147 /* Note the deduced argument packs for this parameter
21148 pack. */
21150 }
21154 {
21155 /* We only had the explicitly-provided arguments before, but
21156 now we have a complete set of arguments. */
21162 }
21163 else
21164 {
21170 /* Inconsistent unification of this parameter pack. */
21172 bad_old_arg,
21173 bad_new_arg);
21174 }
21175 }
21178 }
21180 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
21181 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
21182 parameters and return value are as for unify. */
21184 static int
21188 {
21189 tree parm_max;
21190 tree arg_max;
21194 /* Our representation of array types uses "N - 1" as the
21195 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
21196 not an integer constant. We cannot unify arbitrarily
21197 complex expressions, so we eliminate the MINUS_EXPRs
21198 here. */
21202 {
21205 }
21209 {
21210 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
21211 trying to unify the type of a variable with the type
21212 of a template parameter. For example:
21214 template <unsigned int N>
21215 void f (char (&) [N]);
21216 int g();
21217 void h(int i) {
21218 char a[g(i)];
21219 f(a);
21220 }
21222 Here, the type of the ARG will be "int [g(i)]", and
21223 may be a SAVE_EXPR, etc. */
21227 }
21229 /* If only one of the bounds used a MINUS_EXPR, compensate
21230 by adding one to the other bound. */
21233 integer_type_node,
21234 parm_max,
21235 integer_one_node);
21238 integer_type_node,
21239 arg_max,
21240 integer_one_node);
21244 }
21246 /* Returns whether T, a P or A in unify, is a type, template or expression. */
21250 static pa_kind_t
21252 {
21261 else
21263 }
21265 /* Deduce the value of template parameters. TPARMS is the (innermost)
21266 set of template parameters to a template. TARGS is the bindings
21267 for those template parameters, as determined thus far; TARGS may
21268 include template arguments for outer levels of template parameters
21269 as well. PARM is a parameter to a template function, or a
21270 subcomponent of that parameter; ARG is the corresponding argument.
21271 This function attempts to match PARM with ARG in a manner
21272 consistent with the existing assignments in TARGS. If more values
21273 are deduced, then TARGS is updated.
21275 Returns 0 if the type deduction succeeds, 1 otherwise. The
21276 parameter STRICT is a bitwise or of the following flags:
21278 UNIFY_ALLOW_NONE:
21279 Require an exact match between PARM and ARG.
21280 UNIFY_ALLOW_MORE_CV_QUAL:
21281 Allow the deduced ARG to be more cv-qualified (by qualification
21282 conversion) than ARG.
21283 UNIFY_ALLOW_LESS_CV_QUAL:
21284 Allow the deduced ARG to be less cv-qualified than ARG.
21285 UNIFY_ALLOW_DERIVED:
21286 Allow the deduced ARG to be a template base class of ARG,
21287 or a pointer to a template base class of the type pointed to by
21288 ARG.
21289 UNIFY_ALLOW_INTEGER:
21290 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
21291 case for more information.
21292 UNIFY_ALLOW_OUTER_LEVEL:
21293 This is the outermost level of a deduction. Used to determine validity
21294 of qualification conversions. A valid qualification conversion must
21295 have const qualified pointers leading up to the inner type which
21296 requires additional CV quals, except at the outer level, where const
21297 is not required [conv.qual]. It would be normal to set this flag in
21298 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
21299 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
21300 This is the outermost level of a deduction, and PARM can be more CV
21301 qualified at this point.
21302 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
21303 This is the outermost level of a deduction, and PARM can be less CV
21304 qualified at this point. */
21306 static int
21309 {
21311 tree targ;
21312 tree tparm;
21314 tsubst_flags_t complain = (explain_p
21315 ? tf_warning_or_error
21318 /* I don't think this will do the right thing with respect to types.
21319 But the only case I've seen it in so far has been array bounds, where
21320 signedness is the only information lost, and I think that will be
21321 okay. */
21329 /* We can't deduce anything from this, but we might get all the
21330 template args from other function args. */
21336 /* If PARM uses template parameters, then we can't bail out here,
21337 even if ARG == PARM, since we won't record unifications for the
21338 template parameters. We might need them if we're trying to
21339 figure out which of two things is more specialized. */
21343 /* Handle init lists early, so the rest of the function can assume
21344 we're dealing with a type. */
21346 {
21351 /* Replace T with std::initializer_list<T> for deduction. */
21358 /* We can only deduce from an initializer list argument if the
21359 parameter is std::initializer_list or an array; otherwise this
21360 is a non-deduced context. */
21365 else
21366 {
21368 /* Deduction is defined in terms of a single type, so just punt
21369 on the (bizarre) std::initializer_list<T...>. */
21372 }
21375 {
21382 {
21386 /* It should only be possible to get here for a call. */
21388 elt_strict |= maybe_adjust_types_for_deduction
21391 }
21394 explain_p);
21395 }
21399 {
21400 /* Also deduce from the length of the initializer list. */
21407 }
21409 /* If the std::initializer_list<T> deduction worked, replace the
21410 deduced A with std::initializer_list<A>. */
21412 {
21417 }
21419 }
21421 /* If parm and arg aren't the same kind of thing (template, type, or
21422 expression), fail early. */
21426 /* Immediately reject some pairs that won't unify because of
21427 cv-qualification mismatches. */
21430 /* It is the elements of the array which hold the cv quals of an array
21431 type, and the elements might be template type parms. We'll check
21432 when we recurse. */
21434 /* We check the cv-qualifiers when unifying with template type
21435 parameters below. We want to allow ARG `const T' to unify with
21436 PARM `T' for example, when computing which of two templates
21437 is more specialized, for example. */
21451 {
21455 /* In a type which contains a nested-name-specifier, template
21456 argument values cannot be deduced for template parameters used
21457 within the nested-name-specifier. */
21469 /* The PARM is not one we're trying to unify. Just check
21470 to see if it matches ARG. */
21471 {
21476 else
21478 }
21485 /* Check for mixed types and values. */
21493 {
21496 {
21497 /* First try to match ARG directly. */
21499 explain_p);
21501 {
21502 /* Otherwise, look for a suitable base of ARG, as below. */
21509 }
21510 }
21511 /* ARG must be constructed from a template class or a template
21512 template parameter. */
21517 /* Deduce arguments T, i from TT<T> or TT<i>. */
21523 /* Fall through to deduce template name. */
21524 }
21528 {
21529 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
21531 /* Simple cases: Value already set, does match or doesn't. */
21536 }
21537 else
21538 {
21539 /* If PARM is `const T' and ARG is only `int', we don't have
21540 a match unless we are allowing additional qualification.
21541 If ARG is `const int' and PARM is just `T' that's OK;
21542 that binds `const int' to `T'. */
21547 /* Consider the case where ARG is `const volatile int' and
21548 PARM is `const T'. Then, T should be `volatile int'. */
21549 arg = cp_build_qualified_type_real
21554 /* Simple cases: Value already set, does match or doesn't. */
21560 /* Make sure that ARG is not a variable-sized array. (Note
21561 that were talking about variable-sized arrays (like
21562 `int[n]'), rather than arrays of unknown size (like
21563 `int[]').) We'll get very confused by such a type since
21564 the bound of the array is not constant, and therefore
21565 not mangleable. Besides, such types are not allowed in
21566 ISO C++, so we can do as we please here. We do allow
21567 them for 'auto' deduction, since that isn't ABI-exposed. */
21571 /* Strip typedefs as in convert_template_argument. */
21573 }
21575 /* If ARG is a parameter pack or an expansion, we cannot unify
21576 against it unless PARM is also a parameter pack. */
21581 /* If the argument deduction results is a METHOD_TYPE,
21582 then there is a problem.
21583 METHOD_TYPE doesn't map to any real C++ type the result of
21584 the deduction can not be of that type. */
21598 {
21599 /* The PARM is not one we're trying to unify. Just check
21600 to see if it matches ARG. */
21606 }
21612 {
21616 /* We're deducing from an array bound, the type doesn't matter. */
21622 }
21624 /* [temp.deduct.type] If, in the declaration of a function template
21625 with a non-type template-parameter, the non-type
21626 template-parameter is used in an expression in the function
21627 parameter-list and, if the corresponding template-argument is
21628 deduced, the template-argument type shall match the type of the
21629 template-parameter exactly, except that a template-argument
21630 deduced from an array bound may be of any integral type.
21631 The non-type parameter might use already deduced type parameters. */
21634 /* We don't have enough levels of args to do any substitution. This
21636 else
21637 {
21643 {
21647 }
21648 }
21651 /* Template-parameter dependent expression. Just accept it for now.
21652 It will later be processed in convert_template_argument. */
21653 ;
21659 /* Convert the ARG to the type of PARM; the deduced non-type
21660 template argument must exactly match the types of the
21661 corresponding parameter. */
21664 {
21665 /* We haven't deduced the type of this parameter yet. */
21667 /* We deduce from array bounds in try_array_deduction. */
21669 {
21670 /* Deduce it from the non-type argument. */
21675 }
21676 else
21677 /* Try again later. */
21679 }
21680 else
21683 /* If ARG is a parameter pack or an expansion, we cannot unify
21684 against it unless PARM is also a parameter pack. */
21689 {
21692 }
21697 {
21698 /* A pointer-to-member constant can be unified only with
21699 another constant. */
21703 /* Just unify the class member. It would be useless (and possibly
21704 wrong, depending on the strict flags) to unify also
21705 PTRMEM_CST_CLASS, because we want to be sure that both parm and
21706 arg refer to the same variable, even if through different
21707 classes. For instance:
21709 struct A { int x; };
21710 struct B : A { };
21712 Unification of &A::x and &B::x must succeed. */
21715 }
21718 {
21722 /* [temp.deduct.call]
21724 A can be another pointer or pointer to member type that can
21725 be converted to the deduced A via a qualification
21726 conversion (_conv.qual_).
21728 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
21729 This will allow for additional cv-qualification of the
21730 pointed-to types if appropriate. */
21733 /* The derived-to-base conversion only persists through one
21734 level of pointers. */
21739 }
21771 /* We have already checked cv-qualification at the top of the
21772 function. */
21776 /* As far as unification is concerned, this wins. Later checks
21777 will invalidate it if necessary. */
21780 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
21781 /* Type INTEGER_CST can come from ordinary constant template args. */
21793 {
21803 /* Check for pack expansions in the parameters. */
21805 {
21807 {
21809 /* We can unify against something with a trailing
21810 parameter pack. */
21812 else
21813 /* [temp.deduct.type]/9: If the template argument list of
21814 P contains a pack expansion that is not the last
21815 template argument, the entire template argument list
21816 is a non-deduced context. */
21818 }
21819 }
21821 /* If we don't have enough arguments to satisfy the parameters
21822 (not counting the pack expression at the end), or we have
21823 too many arguments for a parameter list that doesn't end in
21824 a pack expression, we can't unify. */
21830 /* Unify all of the parameters that precede the (optional)
21831 pack expression. */
21833 {
21838 }
21841 DEDUCE_EXACT,
21844 }
21852 {
21860 }
21865 {
21869 {
21870 /* First, we try to unify the PARM and ARG directly. */
21875 {
21876 /* Fallback to the special case allowed in
21877 [temp.deduct.call]:
21879 If P is a class, and P has the form
21880 template-id, then A can be a derived class of
21881 the deduced A. Likewise, if P is a pointer to
21882 a class of the form template-id, A can be a
21883 pointer to a derived class pointed to by the
21884 deduced A. */
21890 {
21891 /* Don't give the derived diagnostic if we're
21892 already dealing with the same template. */
21893 bool same_template
21899 }
21900 }
21901 }
21905 /* Perhaps PARM is something like S<U> and ARG is S<int>.
21906 Then, we should unify `int' and `U'. */
21908 else
21909 /* There's no chance of unification succeeding. */
21914 }
21921 {
21924 tree a;
21930 /* CV qualifications for methods can never be deduced, they must
21931 match exactly. We need to check them explicitly here,
21932 because type_unification_real treats them as any other
21933 cv-qualified parameter. */
21935 && (!check_cv_quals_for_unify
21963 {
21975 }
21978 }
21981 /* Unify a pointer to member with a pointer to member function, which
21982 deduces the type of the member as a function type. */
21984 {
21985 /* Check top-level cv qualifiers */
21993 /* Determine the type of the function we are unifying against. */
21997 }
22016 /* Matched cases are handled by the ARG == PARM test above. */
22020 /* We might get a variable as a non-type template argument in parm if the
22021 corresponding parameter is type-dependent. Make any necessary
22022 adjustments based on whether arg is a reference. */
22026 {
22031 }
22032 /* Now use the normal expression code to check whether they match. */
22043 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
22044 or UNDERLYING_TYPE nodes. */
22048 /* Unification fails if we hit an error node. */
22053 {
22063 }
22064 /* FALLTHRU */
22067 /* An unresolved overload is a nondeduced context. */
22071 expr:
22072 /* We must be looking at an expression. This can happen with
22073 something like:
22075 template <int I>
22076 void foo(S<I>, S<I + 2>);
22078 This is a "nondeduced context":
22080 [deduct.type]
22082 The nondeduced contexts are:
22084 --A type that is a template-id in which one or more of
22085 the template-arguments is an expression that references
22086 a template-parameter.
22088 In these cases, we assume deduction succeeded, but don't
22089 actually infer any unifications. */
22094 else
22096 }
22097 }
22098 #undef RECUR_AND_CHECK_FAILURE
22099 \f
22100 /* Note that DECL can be defined in this translation unit, if
22101 required. */
22103 static void
22105 {
22106 tree clone;
22110 }
22112 /* Called if RESULT is explicitly instantiated, or is a member of an
22113 explicitly instantiated class. */
22115 void
22117 {
22120 /* If this entity has already been written out, it's too late to
22121 make any modifications. */
22125 /* For anonymous namespace we don't need to do anything. */
22127 {
22130 }
22133 /* The TREE_PUBLIC flag for function declarations will have been
22134 set correctly by tsubst. */
22137 /* This might have been set by an earlier implicit instantiation. */
22142 else
22143 {
22146 /* Always make artificials weak. */
22149 /* For WIN32 we also want to put explicit instantiations in
22150 linkonce sections. */
22153 }
22155 /* If EXTERN_P, then this function will not be emitted -- unless
22156 followed by an explicit instantiation, at which point its linkage
22157 will be adjusted. If !EXTERN_P, then this function will be
22158 emitted here. In neither circumstance do we want
22159 import_export_decl to adjust the linkage. */
22161 }
22163 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
22164 important template arguments. If any are missing, we check whether
22165 they're important by using error_mark_node for substituting into any
22166 args that were used for partial ordering (the ones between ARGS and END)
22167 and seeing if it bubbles up. */
22169 static bool
22171 {
22176 {
22179 }
22181 {
22185 }
22187 }
22189 /* Given two function templates PAT1 and PAT2, return:
22191 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
22192 -1 if PAT2 is more specialized than PAT1.
22193 0 if neither is more specialized.
22195 LEN indicates the number of parameters we should consider
22196 (defaulted parameters should not be considered).
22198 The 1998 std underspecified function template partial ordering, and
22199 DR214 addresses the issue. We take pairs of arguments, one from
22200 each of the templates, and deduce them against each other. One of
22201 the templates will be more specialized if all the *other*
22202 template's arguments deduce against its arguments and at least one
22203 of its arguments *does* *not* deduce against the other template's
22204 corresponding argument. Deduction is done as for class templates.
22205 The arguments used in deduction have reference and top level cv
22206 qualifiers removed. Iff both arguments were originally reference
22207 types *and* deduction succeeds in both directions, an lvalue reference
22208 wins against an rvalue reference and otherwise the template
22209 with the more cv-qualified argument wins for that pairing (if
22210 neither is more cv-qualified, they both are equal). Unlike regular
22211 deduction, after all the arguments have been deduced in this way,
22212 we do *not* verify the deduced template argument values can be
22213 substituted into non-deduced contexts.
22215 The logic can be a bit confusing here, because we look at deduce1 and
22216 targs1 to see if pat2 is at least as specialized, and vice versa; if we
22217 can find template arguments for pat1 to make arg1 look like arg2, that
22218 means that arg2 is at least as specialized as arg1. */
22220 int
22222 {
22235 /* Remove the this parameter from non-static member functions. If
22236 one is a non-static member function and the other is not a static
22237 member function, remove the first parameter from that function
22238 also. This situation occurs for operator functions where we
22239 locate both a member function (with this pointer) and non-member
22240 operator (with explicit first operand). */
22242 {
22247 }
22249 {
22252 {
22253 len--;
22255 }
22256 }
22258 /* If only one is a conversion operator, they are unordered. */
22262 /* Consider the return type for a conversion function */
22264 {
22267 len++;
22268 }
22270 processing_template_decl++;
22276 /* Stop when an ellipsis is seen. */
22278 {
22289 {
22290 /* When both arguments are pack expansions, we need only
22291 unify the patterns themselves. */
22295 /* This is the last comparison we need to do. */
22297 }
22299 /* DR 1847: If a particular P contains no template-parameters that
22300 participate in template argument deduction, that P is not used to
22301 determine the ordering. */
22307 {
22311 }
22314 {
22318 }
22324 {
22330 /* Setup the parameter vector, which contains only ARG1. */
22333 /* Setup the argument vector, which contains the remaining
22334 arguments. */
22343 /* We cannot deduce in the other direction, because ARG1 is
22344 a pack expansion but ARG2 is not. */
22346 }
22348 {
22354 /* Setup the parameter vector, which contains only ARG1. */
22357 /* Setup the argument vector, which contains the remaining
22358 arguments. */
22367 /* We cannot deduce in the other direction, because ARG2 is
22368 a pack expansion but ARG1 is not.*/
22370 }
22372 else
22373 {
22374 /* The normal case, where neither argument is a pack
22375 expansion. */
22382 }
22384 /* If we couldn't deduce arguments for tparms1 to make arg1 match
22385 arg2, then arg2 is not as specialized as arg1. */
22391 /* "If, for a given type, deduction succeeds in both directions
22392 (i.e., the types are identical after the transformations above)
22393 and both P and A were reference types (before being replaced with
22394 the type referred to above):
22395 - if the type from the argument template was an lvalue reference and
22396 the type from the parameter template was not, the argument type is
22397 considered to be more specialized than the other; otherwise,
22398 - if the type from the argument template is more cv-qualified
22399 than the type from the parameter template (as described above),
22400 the argument type is considered to be more specialized than the other;
22401 otherwise,
22402 - neither type is more specialized than the other." */
22405 {
22407 {
22410 else
22412 }
22414 {
22419 }
22420 }
22423 /* We've failed to deduce something in either direction.
22424 These must be unordered. */
22427 next:
22431 /* We have already processed all of the arguments in our
22432 handing of the pack expansion type. */
22437 }
22439 /* "In most cases, all template parameters must have values in order for
22440 deduction to succeed, but for partial ordering purposes a template
22441 parameter may remain without a value provided it is not used in the
22442 types being used for partial ordering."
22444 Thus, if we are missing any of the targs1 we need to substitute into
22445 origs1, then pat2 is not as specialized as pat1. This can happen when
22446 there is a nondeduced context. */
22452 processing_template_decl--;
22454 /* If both deductions succeed, the partial ordering selects the more
22455 constrained template. */
22457 {
22462 }
22464 /* All things being equal, if the next argument is a pack expansion
22465 for one function but not for the other, prefer the
22466 non-variadic function. FIXME this is bogus; see c++/41958. */
22470 {
22473 }
22479 else
22481 }
22483 /* Determine which of two partial specializations of TMPL is more
22484 specialized.
22486 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
22487 to the first partial specialization. The TREE_PURPOSE is the
22488 innermost set of template parameters for the partial
22489 specialization. PAT2 is similar, but for the second template.
22491 Return 1 if the first partial specialization is more specialized;
22492 -1 if the second is more specialized; 0 if neither is more
22493 specialized.
22495 See [temp.class.order] for information about determining which of
22496 two templates is more specialized. */
22498 static int
22500 {
22501 tree targs;
22510 /* Just like what happens for functions, if we are ordering between
22511 different template specializations, we may encounter dependent
22512 types in the arguments, and we need our dependency check functions
22513 to behave correctly. */
22517 {
22520 }
22524 {
22527 }
22530 /* If both deductions succeed, the partial ordering selects the more
22531 constrained template. */
22535 /* In the case of a tie where at least one of the templates
22536 has a parameter pack at the end, the template with the most
22537 non-packed parameters wins. */
22539 && any_deductions
22542 {
22548 /* We don't count the pack expansion at the end. */
22558 }
22561 }
22563 /* Return the template arguments that will produce the function signature
22564 DECL from the function template FN, with the explicit template
22565 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
22566 also match. Return NULL_TREE if no satisfactory arguments could be
22567 found. */
22569 static tree
22571 {
22575 tree decl_arg_types;
22578 tree arg;
22582 /* Never do unification on the 'this' parameter. */
22603 }
22605 /* Return the innermost template arguments that, when applied to a partial
22606 specialization SPEC_TMPL of TMPL, yield the ARGS.
22608 For example, suppose we have:
22610 template <class T, class U> struct S {};
22611 template <class T> struct S<T*, int> {};
22613 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
22614 partial specialization and the ARGS will be {double*, int}. The resulting
22615 vector will be {double}, indicating that `T' is bound to `double'. */
22617 static tree
22619 {
22621 tree spec_args
22624 tree deduced_args;
22625 tree innermost_deduced_args;
22629 {
22633 innermost_deduced_args);
22634 }
22635 else
22639 again:
22648 {
22650 {
22656 }
22658 }
22661 {
22664 }
22666 /* Verify that nondeduced template arguments agree with the type
22667 obtained from argument deduction.
22669 For example:
22671 struct A { typedef int X; };
22672 template <class T, class U> struct C {};
22673 template <class T> struct C<T, typename T::X> {};
22675 Then with the instantiation `C<A, int>', we can deduce that
22676 `T' is `A' but unify () does not check whether `typename T::X'
22677 is `int'. */
22688 /* We only need to check the innermost arguments; the other
22689 arguments will always agree. */
22694 /* Now that we have bindings for all of the template arguments,
22695 ensure that the arguments deduced for the template template
22696 parameters have compatible template parameter lists. See the use
22697 of template_template_parm_bindings_ok_p in fn_type_unification
22698 for more information. */
22703 }
22705 // Compare two function templates T1 and T2 by deducing bindings
22706 // from one against the other. If both deductions succeed, compare
22707 // constraints to see which is more constrained.
22708 static int
22710 {
22715 {
22718 }
22721 {
22724 }
22726 // If both deductions succeed, then one may be more constrained.
22731 }
22733 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
22734 Return the TREE_LIST node with the most specialized template, if
22735 any. If there is no most specialized template, the error_mark_node
22736 is returned.
22738 Note that this function does not look at, or modify, the
22739 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
22740 returned is one of the elements of INSTANTIATIONS, callers may
22741 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
22742 and retrieve it from the value returned. */
22744 tree
22746 {
22753 {
22759 {
22760 /* Equally specialized, move to next function. If there
22761 is no next function, nothing's most specialized. */
22766 }
22767 }
22770 /* Now verify that champ is better than everything earlier in the
22771 instantiation list. */
22774 {
22777 }
22778 }
22780 processing_template_decl--;
22786 }
22788 /* If DECL is a specialization of some template, return the most
22789 general such template. Otherwise, returns NULL_TREE.
22791 For example, given:
22793 template <class T> struct S { template <class U> void f(U); };
22795 if TMPL is `template <class U> void S<int>::f(U)' this will return
22796 the full template. This function will not trace past partial
22797 specializations, however. For example, given in addition:
22799 template <class T> struct S<T*> { template <class U> void f(U); };
22801 if TMPL is `template <class U> void S<int*>::f(U)' this will return
22802 `template <class T> template <class U> S<T*>::f(U)'. */
22804 tree
22806 {
22808 {
22811 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
22812 template friend, or a FIELD_DECL for a capture pack. */
22815 }
22817 /* Look for more and more general templates. */
22819 {
22820 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
22821 (See cp-tree.h for details.) */
22830 /* Stop if we run into an explicitly specialized class template. */
22837 }
22840 }
22842 /* Return the most specialized of the template partial specializations
22843 which can produce TARGET, a specialization of some class or variable
22844 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
22845 a TEMPLATE_DECL node corresponding to the partial specialization, while
22846 the TREE_PURPOSE is the set of template arguments that must be
22847 substituted into the template pattern in order to generate TARGET.
22849 If the choice of partial specialization is ambiguous, a diagnostic
22850 is issued, and the error_mark_node is returned. If there are no
22851 partial specializations matching TARGET, then NULL_TREE is
22852 returned, indicating that the primary template should be used. */
22854 static tree
22856 {
22858 tree t;
22859 tree champ;
22866 {
22870 }
22872 {
22875 }
22877 {
22881 }
22882 else
22887 /* For determining which partial specialization to use, only the
22888 innermost args are interesting. */
22890 {
22893 }
22896 {
22897 tree spec_args;
22901 {
22902 /* Substitute in the template args from the enclosing class. */
22906 }
22913 {
22917 /* Keep the candidate only if the constraints are satisfied,
22918 or if we're not compiling with concepts. */
22921 {
22924 }
22925 }
22926 }
22936 {
22939 ;
22940 else
22941 {
22943 {
22946 {
22949 }
22950 }
22952 }
22953 }
22957 {
22960 {
22963 }
22964 }
22967 {
22974 else
22978 {
22983 }
22986 }
22989 }
22991 /* Explicitly instantiate DECL. */
22993 void
22995 {
23000 /* An error occurred, for which grokdeclarator has already issued
23001 an appropriate message. */
23004 {
23007 }
23013 {
23014 /* There is an asymmetry here in the way VAR_DECLs and
23015 FUNCTION_DECLs are handled by grokdeclarator. In the case of
23016 the latter, the DECL we get back will be marked as a
23017 template instantiation, and the appropriate
23018 DECL_TEMPLATE_INFO will be set up. This does not happen for
23019 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
23020 should handle VAR_DECLs as it currently handles
23021 FUNCTION_DECLs. */
23023 {
23026 }
23029 {
23032 }
23034 {
23039 }
23040 }
23042 {
23045 }
23046 else
23049 /* Check for various error cases. Note that if the explicit
23050 instantiation is valid the RESULT will currently be marked as an
23051 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
23052 until we get here. */
23055 {
23056 /* DR 259 [temp.spec].
23058 Both an explicit instantiation and a declaration of an explicit
23059 specialization shall not appear in a program unless the explicit
23060 instantiation follows a declaration of the explicit specialization.
23062 For a given set of template parameters, if an explicit
23063 instantiation of a template appears after a declaration of an
23064 explicit specialization for that template, the explicit
23065 instantiation has no effect. */
23067 }
23069 {
23070 /* [temp.spec]
23072 No program shall explicitly instantiate any template more
23073 than once.
23075 We check DECL_NOT_REALLY_EXTERN so as not to complain when
23076 the first instantiation was `extern' and the second is not,
23077 and EXTERN_P for the opposite case. */
23080 /* If an "extern" explicit instantiation follows an ordinary
23081 explicit instantiation, the template is instantiated. */
23084 }
23086 {
23089 }
23091 {
23094 }
23097 ;
23099 {
23102 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
23105 }
23106 else
23114 }
23116 static void
23118 {
23124 {
23127 }
23128 }
23130 /* Called from do_type_instantiation through binding_table_foreach to
23131 do recursive instantiation for the type bound in ENTRY. */
23132 static void
23134 {
23141 }
23143 /* Perform an explicit instantiation of template class T. STORAGE, if
23144 non-null, is the RID for extern, inline or static. COMPLAIN is
23145 nonzero if this is called from the parser, zero if called recursively,
23146 since the standard is unclear (as detailed below). */
23148 void
23150 {
23160 {
23161 tree tmpl =
23165 else
23168 }
23173 {
23176 t);
23178 }
23181 {
23183 {
23185 {
23188 "ISO C++ 1998 forbids the use of %<extern%> on "
23190 }
23191 else
23193 "ISO C++ forbids the use of %qE"
23195 }
23203 else
23204 {
23206 storage);
23208 }
23209 }
23212 {
23213 /* DR 259 [temp.spec].
23215 Both an explicit instantiation and a declaration of an explicit
23216 specialization shall not appear in a program unless the explicit
23217 instantiation follows a declaration of the explicit specialization.
23219 For a given set of template parameters, if an explicit
23220 instantiation of a template appears after a declaration of an
23221 explicit specialization for that template, the explicit
23222 instantiation has no effect. */
23224 }
23226 {
23227 /* [temp.spec]
23229 No program shall explicitly instantiate any template more
23230 than once.
23232 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
23233 instantiation was `extern'. If EXTERN_P then the second is.
23234 These cases are OK. */
23241 /* If we've already instantiated the template, just return now. */
23244 }
23252 /* In contrast to implicit instantiation, where only the
23253 declarations, and not the definitions, of members are
23254 instantiated, we have here:
23256 [temp.explicit]
23258 The explicit instantiation of a class template specialization
23259 implies the instantiation of all of its members not
23260 previously explicitly specialized in the translation unit
23261 containing the explicit instantiation.
23263 Of course, we can't instantiate member template classes, since we
23264 don't have any arguments for them. Note that the standard is
23265 unclear on whether the instantiation of the members are
23266 *explicit* instantiations or not. However, the most natural
23267 interpretation is that it should be an explicit
23268 instantiation. */
23272 && !static_p
23275 {
23280 }
23285 }
23287 /* Given a function DECL, which is a specialization of TMPL, modify
23288 DECL to be a re-instantiation of TMPL with the same template
23289 arguments. TMPL should be the template into which tsubst'ing
23290 should occur for DECL, not the most general template.
23292 One reason for doing this is a scenario like this:
23294 template <class T>
23295 void f(const T&, int i);
23297 void g() { f(3, 7); }
23299 template <class T>
23300 void f(const T& t, const int i) { }
23302 Note that when the template is first instantiated, with
23303 instantiate_template, the resulting DECL will have no name for the
23304 first parameter, and the wrong type for the second. So, when we go
23305 to instantiate the DECL, we regenerate it. */
23307 static void
23309 {
23310 /* The arguments used to instantiate DECL, from the most general
23311 template. */
23312 tree code_pattern;
23316 /* Make sure that we can see identifiers, and compute access
23317 correctly. */
23321 {
23322 tree decl_parm;
23323 tree pattern_parm;
23324 tree specs;
23338 specs);
23340 /* Merge parameter declarations. */
23343 pattern_parm
23347 {
23348 tree parm_type;
23349 tree attributes;
23354 NULL_TREE);
23360 {
23363 }
23366 }
23367 /* Merge any parameters that match with the function parameter
23368 pack. */
23370 {
23372 tree expanded_types;
23373 /* Expand the TYPE_PACK_EXPANSION that provides the types for
23374 the parameters in this function parameter pack. */
23379 {
23380 tree parm_type;
23381 tree attributes;
23384 /* Rename the parameter to include the index. */
23393 {
23396 }
23398 }
23399 }
23400 /* Merge additional specifiers from the CODE_PATTERN. */
23404 }
23406 {
23416 }
23417 else
23421 }
23423 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
23424 substituted to get DECL. */
23426 tree
23428 {
23431 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
23432 for the instantiation. This is not always the most general
23433 template. Consider, for example:
23435 template <class T>
23436 struct S { template <class U> void f();
23437 template <> void f<int>(); };
23439 and an instantiation of S<double>::f<int>. We want TD to be the
23440 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
23442 more general template. */
23444 /* We must also deal with friend templates. Given:
23446 template <class T> struct S {
23447 template <class U> friend void f() {};
23448 };
23450 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
23451 so far as the language is concerned, but that's still
23452 where we get the pattern for the instantiation from. On
23453 other hand, if the definition comes outside the class, say:
23455 template <class T> struct S {
23456 template <class U> friend void f();
23457 };
23458 template <class U> friend void f() {}
23460 we don't need to look any further. That's what the check for
23461 DECL_INITIAL is for. */
23465 {
23466 /* The present template, TD, should not be a definition. If it
23467 were a definition, we should be using it! Note that we
23468 cannot restructure the loop to just keep going until we find
23469 a template with a definition, since that might go too far if
23470 a specialization was declared, but not defined. */
23472 /* Fetch the more general template. */
23474 }
23477 }
23479 /* Returns true if we need to instantiate this template instance even if we
23480 know we aren't going to emit it. */
23482 bool
23484 {
23485 /* We always instantiate inline functions so that we can inline them. An
23486 explicit instantiation declaration prohibits implicit instantiation of
23487 non-inline functions. With high levels of optimization, we would
23488 normally inline non-inline functions -- but we're not allowed to do
23489 that for "extern template" functions. Therefore, we check
23490 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
23494 /* And we need to instantiate static data members so that
23495 their initializers are available in integral constant
23496 expressions. */
23499 }
23501 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
23502 instantiate it now, modifying TREE_TYPE (fn). Returns false on
23503 error, true otherwise. */
23505 bool
23507 {
23510 /* Don't instantiate a noexcept-specification from template context. */
23526 {
23532 {
23533 /* If hash_set::add returns true, the element was already there. */
23538 fn);
23540 }
23542 {
23557 }
23558 else
23568 }
23571 {
23574 else
23576 }
23579 }
23581 /* We're starting to process the function INST, an instantiation of PATTERN;
23582 add their parameters to local_specializations. */
23584 static void
23586 {
23590 {
23594 }
23596 {
23598 {
23601 }
23602 else
23603 {
23604 /* Register the (value) argument pack as a specialization of
23605 TMPL_PARM, then move on. */
23608 }
23609 }
23611 }
23613 /* Produce the definition of D, a _DECL generated from a template. If
23614 DEFER_OK is true, then we don't have to actually do the
23615 instantiation now; we just have to do it sometime. Normally it is
23616 an error if this is an explicit instantiation but D is undefined.
23617 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
23618 instantiated class template. */
23620 tree
23622 {
23624 tree gen_args;
23625 tree args;
23626 tree td;
23627 tree code_pattern;
23628 tree spec;
23629 tree gen_tmpl;
23637 /* This function should only be used to instantiate templates for
23638 functions and static member variables. */
23641 /* A concept is never instantiated. */
23644 /* Variables are never deferred; if instantiation is required, they
23645 are instantiated right away. That allows for better code in the
23646 case that an expression refers to the value of the variable --
23647 if the variable has a constant value the referring expression can
23648 take advantage of that fact. */
23652 /* Don't instantiate cloned functions. Instead, instantiate the
23653 functions they cloned. */
23661 /* D has already been instantiated or explicitly specialized, so
23662 there's nothing for us to do here.
23664 It might seem reasonable to check whether or not D is an explicit
23665 instantiation, and, if so, stop here. But when an explicit
23666 instantiation is deferred until the end of the compilation,
23667 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
23668 the instantiation. */
23671 /* Check to see whether we know that this template will be
23672 instantiated in some other file, as with "extern template"
23673 extension. */
23676 /* In general, we do not instantiate such templates. */
23684 /* We should already have the extra args. */
23687 /* And what's in the hash table should match D. */
23691 /* This needs to happen before any tsubsting. */
23697 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
23698 for the instantiation. */
23703 {
23704 /* Look up an explicit specialization, if any. */
23708 {
23711 }
23712 }
23716 /* We should never be trying to instantiate a member of a class
23717 template or partial specialization. */
23722 /* In the case of a friend template whose definition is provided
23723 outside the class, we may have too many arguments. Drop the
23724 ones we don't need. The same is true for specializations. */
23725 args = get_innermost_template_args
23729 {
23735 }
23736 else
23737 {
23742 else
23744 }
23746 /* We may be in the middle of deferred access check. Disable it now. */
23749 /* Unless an explicit instantiation directive has already determined
23750 the linkage of D, remember that a definition is available for
23751 this entity. */
23761 /* If D is a member of an explicitly instantiated class template,
23762 and no definition is available, treat it like an implicit
23763 instantiation. */
23766 {
23767 /* Leave linkage flags alone on instantiations with anonymous
23768 visibility. */
23770 {
23773 }
23775 }
23777 /* Defer all other templates, unless we have been explicitly
23778 forbidden from doing so. */
23780 template. */
23781 ! pattern_defined
23782 /* If it's OK to postpone instantiation, do so. */
23783 || defer_ok
23784 /* If this is a static data member that will be defined
23785 elsewhere, we don't want to instantiate the entire data
23786 member, but we do want to instantiate the initializer so that
23787 we can substitute that elsewhere. */
23789 /* Handle here a deleted function too, avoid generating
23790 its body (c++/61080). */
23792 {
23793 /* The definition of the static data member is now required so
23794 we must substitute the initializer. */
23798 {
23799 tree ns;
23800 tree init;
23809 args,
23812 /* If instantiating the initializer involved instantiating this
23813 again, don't call cp_finish_decl twice. */
23815 {
23816 /* Make sure the initializer is still constant, in case of
23817 circular dependency (template/instantiate6.C). */
23818 const_init
23822 LOOKUP_ONLYCONVERTING);
23823 }
23827 }
23829 /* We restore the source position here because it's used by
23830 add_pending_template. */
23836 /* [temp.explicit]
23838 The definition of a non-exported function template, a
23839 non-exported member function template, or a non-exported
23840 member function or static data member of a class template
23841 shall be present in every translation unit in which it is
23842 explicitly instantiated. */
23846 /* If we're in unevaluated context, we just wanted to get the
23847 constant value; this isn't an odr use, so don't queue
23848 a full instantiation. */
23851 /* ??? Historically, we have instantiated inline functions, even
23852 when marked as "extern template". */
23856 }
23857 /* Tell the repository that D is available in this translation unit
23858 -- and see if it is supposed to be instantiated here. */
23860 {
23861 /* In a PCH file, despite the fact that the repository hasn't
23862 requested instantiation in the PCH it is still possible that
23863 an instantiation will be required in a file that includes the
23864 PCH. */
23867 /* Instantiate inline functions so that the inliner can do its
23868 job, even though we'll not be emitting a copy of this
23869 function. */
23872 }
23875 tree fn_context;
23878 /* tsubst_lambda_expr resolved any references to enclosing functions. */
23889 else
23890 {
23895 }
23897 /* Mark D as instantiated so that recursive calls to
23898 instantiate_decl do not try to instantiate it again. */
23901 /* Regenerate the declaration in case the template has been modified
23902 by a subsequent redeclaration. */
23905 /* We already set the file and line above. Reset them now in case
23906 they changed as a result of calling regenerate_decl_from_template. */
23910 {
23911 tree init;
23914 /* Clear out DECL_RTL; whatever was there before may not be right
23915 since we've reset the type of the declaration. */
23919 /* The initializer is placed in DECL_INITIAL by
23920 regenerate_decl_from_template so we don't need to
23921 push/pop_access_scope again here. Pull it out so that
23922 cp_finish_decl can process it. */
23927 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
23928 initializer. That function will defer actual emission until
23929 we have a chance to determine linkage. */
23932 /* Enter the scope of D so that access-checking works correctly. */
23945 }
23949 {
23950 /* Set up the list of local specializations. */
23954 /* Set up context. */
23958 else
23961 /* Some typedefs referenced from within the template code need to be
23962 access checked at template instantiation time, i.e now. These
23963 types were added to the template at parsing time. Let's get those
23964 and perform the access checks then. */
23966 args);
23968 /* Create substitution entries for the parameters. */
23971 /* Substitute into the body of the function. */
23975 else
23976 {
23981 /* Set the current input_location to the end of the function
23982 so that finish_function knows where we are. */
23983 input_location
23986 /* Remember if we saw an infinite loop in the template. */
23987 current_function_infinite_loop
23989 }
23991 /* Finish the function. */
23995 else
23996 {
23999 }
24003 }
24005 /* We're not deferring instantiation any more. */
24010 else
24016 out:
24025 }
24027 /* Run through the list of templates that we wish we could
24028 instantiate, and instantiate any we can. RETRIES is the
24029 number of times we retry pending template instantiation. */
24031 void
24033 {
24037 /* Instantiating templates may trigger vtable generation. This in turn
24038 may require further template instantiations. We place a limit here
24039 to avoid infinite loop. */
24041 {
24045 "template instantiation depth exceeds maximum of %d"
24046 " instantiating %q+D, possibly from virtual table generation"
24050 /* Pretend that we defined it. */
24053 }
24055 do
24056 {
24061 {
24066 {
24068 {
24083 }
24086 }
24087 else
24088 {
24091 {
24092 instantiation
24098 }
24102 }
24105 {
24106 /* If INSTANTIATION has been instantiated, then we don't
24107 need to consider it again in the future. */
24112 }
24113 else
24114 {
24117 }
24120 }
24122 }
24126 }
24128 /* Substitute ARGVEC into T, which is a list of initializers for
24129 either base class or a non-static data member. The TREE_PURPOSEs
24130 are DECLs, and the TREE_VALUEs are the initializer values. Used by
24131 instantiate_decl. */
24133 static tree
24135 {
24140 {
24141 tree decl;
24142 tree init;
24148 {
24149 tree expr;
24150 tree arg;
24152 /* Expand the base class expansion type into separate base
24153 classes. */
24155 tf_warning_or_error,
24156 NULL_TREE);
24160 /* We'll be building separate TREE_LISTs of arguments for
24161 each base. */
24167 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
24168 expand each argument in the TREE_VALUE of t. */
24175 /* VOID_TYPE_NODE is used to indicate
24176 value-initialization. */
24177 {
24180 }
24181 else
24182 {
24183 /* Substitute parameter packs into each argument in the
24184 TREE_LIST. */
24187 {
24188 tree expanded_exprs;
24190 /* Expand the argument. */
24192 expanded_exprs
24194 tf_warning_or_error,
24195 NULL_TREE);
24199 /* Prepend each of the expanded expressions to the
24200 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
24202 {
24207 }
24208 }
24211 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
24212 since we built them backwards. */
24214 {
24217 }
24218 }
24219 }
24222 {
24224 {
24228 }
24229 else
24230 {
24231 tree tmp;
24246 /* If we had an initializer but it instantiated to nothing,
24247 value-initialize the object. This will only occur when
24248 the initializer was a pack expansion where the parameter
24249 packs used in that expansion were of length zero. */
24252 }
24256 {
24258 decl);
24260 }
24261 /* Look for a target constructor. */
24265 {
24268 {
24272 }
24274 }
24277 {
24281 }
24282 }
24283 }
24285 }
24287 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
24289 static void
24291 {
24296 else
24298 }
24300 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
24301 is the instantiation (which should have been created with
24302 start_enum) and ARGS are the template arguments to use. */
24304 static void
24306 {
24307 tree e;
24313 {
24314 tree value;
24315 tree decl;
24318 /* Note that in a template enum, the TREE_VALUE is the
24319 CONST_DECL, not the corresponding INTEGER_CST. */
24324 /* Give this enumeration constant the correct access. */
24327 /* Actually build the enumerator itself. Here we're assuming that
24328 enumerators can't have dependent attributes. */
24331 }
24341 }
24343 /* DECL is a FUNCTION_DECL that is a template specialization. Return
24344 its type -- but without substituting the innermost set of template
24345 arguments. So, innermost set of template parameters will appear in
24346 the type. */
24348 tree
24350 {
24351 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
24353 }
24355 /* Return truthvalue if we're processing a template different from
24356 the last one involved in diagnostics. */
24357 bool
24359 {
24361 }
24363 /* Remember current template involved in diagnostics. */
24364 void
24366 {
24368 }
24372 {
24374 }
24376 /* Return TRUE if current_function_decl is being instantiated, false
24377 otherwise. */
24379 bool
24381 {
24385 }
24387 /* [temp.param] Check that template non-type parm TYPE is of an allowable
24388 type. Return false for ok, true for disallowed. Issue error and
24389 inform messages under control of COMPLAIN. */
24391 static bool
24393 {
24411 /* A bound template template parm could later be instantiated to have a valid
24412 nontype parm type via an alias template. */
24418 {
24421 else
24423 type);
24424 }
24426 }
24428 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
24429 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
24431 static bool
24433 {
24434 tree scope;
24436 /* [temp.dep.type]
24438 A type is dependent if it is:
24440 -- a template parameter. Template template parameters are types
24441 for us (since TYPE_P holds true for them) so we handle
24442 them here. */
24446 /* -- a qualified-id with a nested-name-specifier which contains a
24447 class-name that names a dependent type or whose unqualified-id
24448 names a dependent type. */
24452 /* An alias template specialization can be dependent even if the
24453 resulting type is not. */
24457 /* -- a cv-qualified type where the cv-unqualified type is
24458 dependent.
24459 No code is necessary for this bullet; the code below handles
24460 cv-qualified types, and we don't want to strip aliases with
24461 TYPE_MAIN_VARIANT because of DR 1558. */
24462 /* -- a compound type constructed from any dependent type. */
24472 {
24473 tree arg_type;
24478 arg_type;
24483 /* A value-dependent noexcept-specifier makes the type dependent. */
24486 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
24487 affect overload resolution and treating it as dependent breaks
24488 things. */
24493 }
24494 /* -- an array type constructed from any dependent type or whose
24495 size is specified by a constant expression that is
24496 value-dependent.
24498 We checked for type- and value-dependence of the bounds in
24499 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
24501 {
24506 }
24508 /* -- a template-id in which either the template name is a template
24509 parameter ... */
24512 /* ... or any of the template arguments is a dependent type or
24513 an expression that is type-dependent or value-dependent. */
24515 && (any_dependent_template_arguments_p
24519 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
24520 dependent; if the argument of the `typeof' expression is not
24521 type-dependent, then it should already been have resolved. */
24527 /* A template argument pack is dependent if any of its packed
24528 arguments are. */
24530 {
24536 }
24538 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
24539 be template parameters. */
24546 /* The standard does not specifically mention types that are local
24547 to template functions or local classes, but they should be
24548 considered dependent too. For example:
24550 template <int I> void f() {
24551 enum E { a = I };
24552 S<sizeof (E)> s;
24553 }
24555 The size of `E' cannot be known until the value of `I' has been
24556 determined. Therefore, `E' must be considered dependent. */
24560 /* Don't use type_dependent_expression_p here, as it can lead
24561 to infinite recursion trying to determine whether a lambda
24562 nested in a lambda is dependent (c++/47687). */
24566 && (any_dependent_template_arguments_p
24570 /* Other types are non-dependent. */
24572 }
24574 /* Returns TRUE if TYPE is dependent, in the sense of
24575 [temp.dep.type]. Note that a NULL type is considered dependent. */
24577 bool
24579 {
24580 /* If there are no template parameters in scope, then there can't be
24581 any dependent types. */
24583 {
24584 /* If we are not processing a template, then nobody should be
24585 providing us with a dependent type. */
24589 }
24591 /* If the type is NULL, we have not computed a type for the entity
24592 in question; in that case, the type is dependent. */
24596 /* Erroneous types can be considered non-dependent. */
24600 /* Getting here with global_type_node means we improperly called this
24601 function on the TREE_TYPE of an IDENTIFIER_NODE. */
24604 /* If we have not already computed the appropriate value for TYPE,
24605 do so now. */
24607 {
24610 }
24613 }
24615 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
24616 lookup. In other words, a dependent type that is not the current
24617 instantiation. */
24619 bool
24621 {
24624 }
24626 /* T is a SCOPE_REF. Return whether it represents a non-static member of
24627 an unknown base of 'this' (and is therefore instantiation-dependent). */
24629 static bool
24631 {
24648 }
24650 /* T is a SCOPE_REF; return whether we need to consider it
24651 instantiation-dependent so that we can check access at instantiation
24652 time even though we know which member it resolves to. */
24654 static bool
24656 {
24663 else
24665 }
24667 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
24668 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
24669 expression. */
24671 /* Note that this predicate is not appropriate for general expressions;
24672 only constant expressions (that satisfy potential_constant_expression)
24673 can be tested for value dependence. */
24675 bool
24677 {
24681 /* A type-dependent expression is also value-dependent. */
24686 {
24688 /* A dependent member function of the current instantiation. */
24692 /* A dependent member function of the current instantiation. */
24699 /* A name that has not been looked up -- must be dependent. */
24703 /* A non-type template parm. */
24707 /* A non-type template parm. */
24713 /* A constant with literal type and is initialized
24714 with an expression that is value-dependent. */
24716 /* FIXME cp_finish_decl doesn't fold reference initializers. */
24720 {
24724 }
24733 /* These expressions are value-dependent if the type to which
24734 the cast occurs is dependent or the expression being casted
24735 is value-dependent. */
24736 {
24742 /* A functional cast has a list of operands. */
24745 {
24746 /* If there are no operands, it must be an expression such
24747 as "int()". This should not happen for aggregate types
24748 because it would form non-constant expressions. */
24753 }
24759 }
24764 /* FALLTHRU */
24767 /* A `sizeof' expression is value-dependent if the operand is
24768 type-dependent or is a pack expansion. */
24777 /* An 'encode' expression is value-dependent if the operand is
24778 type-dependent. */
24787 /* All instantiation-dependent expressions should also be considered
24788 value-dependent. */
24796 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
24797 is value-dependent. */
24798 {
24807 }
24810 {
24827 }
24838 {
24842 }
24845 /* Treat all requires-expressions as value-dependent so
24846 we don't try to fold them. */
24853 {
24860 {
24862 /* In a call to a constexpr member function, look through the
24863 implicit ADDR_EXPR on the object argument so that it doesn't
24864 cause the call to be considered value-dependent. We also
24865 look through it in potential_constant_expression. */
24872 }
24874 }
24880 {
24882 tree val;
24889 }
24892 /* Treat a GNU statement expression as dependent to avoid crashing
24893 under instantiate_non_dependent_expr; it can't be constant. */
24897 /* A constant expression is value-dependent if any subexpression is
24898 value-dependent. */
24900 {
24907 {
24911 {
24914 /* In some cases, some of the operands may be missing.
24915 (For example, in the case of PREDECREMENT_EXPR, the
24916 amount to increment by may be missing.) That doesn't
24917 make the expression dependent. */
24920 }
24921 }
24925 }
24927 }
24929 /* The expression is not value-dependent. */
24931 }
24933 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
24934 [temp.dep.expr]. Note that an expression with no type is
24935 considered dependent. Other parts of the compiler arrange for an
24936 expression with type-dependent subexpressions to have no type, so
24937 this function doesn't have to be fully recursive. */
24939 bool
24941 {
24950 /* An unresolved name is always dependent. */
24956 /* A fold expression is type-dependent. */
24963 /* Some expression forms are never type-dependent. */
24977 /* The types of these expressions depends only on the type to which
24978 the cast occurs. */
24987 /* The types of these expressions depends only on the type created
24988 by the expression. */
24991 {
24992 /* For NEW_EXPR tree nodes created inside a template, either
24993 the object type itself or a TREE_LIST may appear as the
24994 operand 1. */
24997 /* This is an array type. We need to check array dimensions
24998 as well. */
25000 || value_dependent_expression_p
25002 else
25004 }
25007 {
25011 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
25012 contains an identifier associated by name lookup with one or more
25013 declarations declared with a dependent type, or...a
25014 nested-name-specifier or qualified-id that names a member of an
25015 unknown specialization. */
25018 }
25028 {
25029 tree elt;
25033 {
25036 }
25038 }
25040 /* A static data member of the current instantiation with incomplete
25041 array type is type-dependent, as the definition and specializations
25042 can have different bounds. */
25049 /* An array of unknown bound depending on a variadic parameter, eg:
25051 template<typename... Args>
25052 void foo (Args... args)
25053 {
25054 int arr[] = { args... };
25055 }
25057 template<int... vals>
25058 void bar ()
25059 {
25060 int arr[] = { vals... };
25061 }
25063 If the array has no length and has an initializer, it must be that
25064 we couldn't determine its length in cp_complete_array_type because
25065 it is dependent. */
25073 /* A function or variable template-id is type-dependent if it has any
25074 dependent template arguments. */
25078 {
25079 /* Consider the innermost template arguments, since those are the ones
25080 that come from the template-id; the template arguments for the
25081 enclosing class do not make it type-dependent unless they are used in
25082 the type of the decl. */
25084 && (any_dependent_template_arguments_p
25087 }
25089 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
25090 type-dependent. Checking this is important for functions with auto return
25091 type, which looks like a dependent type. */
25100 {
25104 }
25106 /* Always dependent, on the number of arguments if nothing else. */
25111 {
25116 {
25122 }
25123 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
25128 {
25133 }
25136 {
25143 }
25153 }
25157 /* Dependent type attributes might not have made it from the decl to
25158 the type yet. */
25164 }
25166 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
25167 type-dependent if the expression refers to a member of the current
25168 instantiation and the type of the referenced member is dependent, or the
25169 class member access expression refers to a member of an unknown
25170 specialization.
25172 This function returns true if the OBJECT in such a class member access
25173 expression is of an unknown specialization. */
25175 bool
25177 {
25178 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
25179 dependent. */
25184 }
25186 /* walk_tree callback function for instantiation_dependent_expression_p,
25187 below. Returns non-zero if a dependent subexpression is found. */
25189 static tree
25192 {
25194 {
25195 /* We don't have to worry about decltype currently because decltype
25196 of an instantiation-dependent expr is a dependent type. This
25197 might change depending on the resolution of DR 1172. */
25200 }
25203 {
25204 /* Don't treat an argument list as dependent just because it has no
25205 TREE_TYPE. */
25213 /* Handle expressions with type operands. */
25218 {
25223 {
25226 else
25227 {
25230 }
25231 }
25233 }
25237 /* In a template, finish_class_member_access_expr creates a
25238 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
25239 type-dependent, so that we can check access control at
25240 instantiation time (PR 42277). See also Core issue 1273. */
25247 else
25250 /* Treat statement-expressions as dependent. */
25254 /* Treat requires-expressions as dependent. */
25259 /* Treat calls to function concepts as dependent. */
25265 /* And variable concepts. */
25272 }
25276 else
25278 }
25280 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
25281 sense defined by the ABI:
25283 "An expression is instantiation-dependent if it is type-dependent
25284 or value-dependent, or it has a subexpression that is type-dependent
25285 or value-dependent."
25287 Except don't actually check value-dependence for unevaluated expressions,
25288 because in sizeof(i) we don't care about the value of i. Checking
25289 type-dependence will in turn check value-dependence of array bounds/template
25290 arguments as needed. */
25292 bool
25294 {
25295 tree result;
25306 }
25308 /* As above, but also check value-dependence of the expression as a whole. */
25310 bool
25312 {
25315 }
25317 /* Like type_dependent_expression_p, but it also works while not processing
25318 a template definition, i.e. during substitution or mangling. */
25320 bool
25322 {
25328 }
25330 /* Returns TRUE if ARGS contains a type-dependent expression. */
25332 bool
25334 {
25336 tree arg;
25339 {
25342 }
25344 }
25346 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
25347 expressions) contains any type-dependent expressions. */
25349 bool
25351 {
25357 }
25359 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
25360 expressions) contains any value-dependent expressions. */
25362 bool
25364 {
25370 }
25372 /* Returns TRUE if the ARG (a template argument) is dependent. */
25374 bool
25376 {
25380 /* Assume a template argument that was wrongly written by the user
25381 is dependent. This is consistent with what
25382 any_dependent_template_arguments_p [that calls this function]
25383 does. */
25393 {
25396 /* A member template of a dependent class is not necessarily
25397 type-dependent, but it is a dependent template argument because it
25398 will be a member of an unknown specialization to that template. */
25401 }
25403 {
25407 {
25410 }
25413 }
25416 else
25419 }
25421 /* Returns true if ARGS (a collection of template arguments) contains
25422 any types that require structural equality testing. */
25424 bool
25426 {
25436 {
25439 {
25445 {
25446 /* Look inside the argument pack. */
25449 }
25452 {
25465 }
25466 }
25467 }
25470 }
25472 /* Returns true if ARGS (a collection of template arguments) contains
25473 any dependent arguments. */
25475 bool
25477 {
25487 {
25492 }
25495 }
25497 /* Returns true if ARGS contains any errors. */
25499 bool
25501 {
25509 {
25512 else
25514 }
25520 {
25525 }
25528 }
25530 /* Returns TRUE if the template TMPL is type-dependent. */
25532 bool
25534 {
25536 {
25541 }
25543 /* Template template parameters are dependent. */
25547 /* So are names that have not been looked up. */
25551 }
25553 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
25555 bool
25557 {
25560 }
25562 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
25563 are dependent. */
25565 bool
25567 {
25574 {
25596 {
25600 }
25604 {
25608 {
25613 }
25614 }
25615 }
25618 }
25620 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
25621 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
25622 no such TYPE can be found. Note that this function peers inside
25623 uninstantiated templates and therefore should be used only in
25624 extremely limited situations. ONLY_CURRENT_P restricts this
25625 peering to the currently open classes hierarchy (which is required
25626 when comparing types). */
25628 tree
25630 {
25631 tree scope;
25632 tree name;
25633 tree decl;
25635 tree pushed_scope;
25636 tree result;
25641 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
25644 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
25645 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
25646 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
25647 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
25648 identifier of the TYPENAME_TYPE anymore.
25649 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
25650 TYPENAME_TYPE instead, we avoid messing up with a possible
25651 typedef variant case. */
25654 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
25655 it first before we can figure out what NAME refers to. */
25657 {
25659 /* Given a class template A with a dependent base with nested type C,
25660 typedef typename A::C::C C will land us here, as trying to resolve
25661 the initial A::C leads to the local C typedef, which leads back to
25662 A::C::C. So we break the recursion now. */
25664 else
25666 }
25667 /* If we don't know what SCOPE refers to, then we cannot resolve the
25668 TYPENAME_TYPE. */
25671 /* If this is a typedef, we don't want to look inside (c++/11987). */
25674 /* If SCOPE isn't the template itself, it will not have a valid
25675 TYPE_FIELDS list. */
25677 /* scope is either the template itself or a compatible instantiation
25678 like X<T>, so look up the name in the original template. */
25680 /* If scope has no fields, it can't be a current instantiation. Check this
25681 before currently_open_class to avoid infinite recursion (71515). */
25684 /* If the SCOPE is not the current instantiation, there's no reason
25685 to look inside it. */
25688 /* Enter the SCOPE so that name lookup will be resolved as if we
25689 were in the class definition. In particular, SCOPE will no
25690 longer be considered a dependent type. */
25692 /* Look up the declaration. */
25694 tf_warning_or_error);
25698 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
25699 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
25705 {
25709 }
25712 {
25713 /* Obtain the template and the arguments. */
25716 {
25717 /* We get here with a plain identifier because a previous tentative
25718 parse of the nested-name-specifier as part of a ptr-operator saw
25719 ::template X<A>. The use of ::template is necessary in a
25720 ptr-operator, but wrong in a declarator-id.
25722 [temp.names]: In a qualified-id of a declarator-id, the keyword
25723 template shall not appear at the top level. */
25727 }
25729 /* Instantiate the template. */
25735 }
25737 /* Leave the SCOPE. */
25741 /* If we failed to resolve it, return the original typename. */
25745 /* If lookup found a typename type, resolve that too. */
25747 {
25748 /* Ill-formed programs can cause infinite recursion here, so we
25749 must catch that. */
25753 }
25755 /* Qualify the resulting type. */
25761 }
25763 /* EXPR is an expression which is not type-dependent. Return a proxy
25764 for EXPR that can be used to compute the types of larger
25765 expressions containing EXPR. */
25767 tree
25769 {
25771 tree inner_expr;
25773 /* When checking, try to get a constant value for all non-dependent
25774 expressions in order to expose bugs in *_dependent_expression_p
25775 and constexpr. This can affect code generation, see PR70704, so
25776 only do this for -fchecking=2. */
25779 /* Don't do this during nsdmi parsing as it can lead to
25780 unexpected recursive instantiations. */
25782 /* Don't do this during concept expansion either and for
25783 the same reason. */
25789 /* Preserve OVERLOADs; the functions must be available to resolve
25790 types. */
25801 /* There is no need to return a proxy for a variable. */
25804 /* Preserve string constants; conversions from string constants to
25805 "char *" are allowed, even though normally a "const char *"
25806 cannot be used to initialize a "char *". */
25809 /* Preserve void and arithmetic constants, as an optimization -- there is no
25810 reason to create a new node. */
25815 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
25816 There is at least one place where we want to know that a
25817 particular expression is a throw-expression: when checking a ?:
25818 expression, there are special rules if the second or third
25819 argument is a throw-expression. */
25823 /* Don't wrap an initializer list, we need to be able to look inside. */
25827 /* Don't wrap a dummy object, we need to be able to test for it. */
25846 /* If the type is unknown, it can't really be non-dependent */
25849 /* Otherwise, build a NON_DEPENDENT_EXPR. */
25852 }
25854 /* ARGS is a vector of expressions as arguments to a function call.
25855 Replace the arguments with equivalent non-dependent expressions.
25856 This modifies ARGS in place. */
25858 void
25860 {
25862 tree arg;
25865 {
25869 }
25870 }
25872 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
25873 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
25874 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
25876 static tree
25878 {
25892 }
25894 tree
25896 {
25898 }
25900 tree
25902 {
25904 }
25906 /* Return a C++17 deduction placeholder for class template TMPL. */
25908 tree
25910 {
25914 }
25916 /* True iff T is a C++17 class template deduction placeholder. */
25918 bool
25920 {
25922 }
25924 /* Make a "constrained auto" type-specifier. This is an
25925 auto type with constraints that must be associated after
25926 deduction. The constraint is formed from the given
25927 CONC and its optional sequence of arguments, which are
25928 non-null if written as partial-concept-id. */
25930 tree
25932 {
25935 /* Build the constraint. */
25943 /* Our canonical type depends on the constraint. */
25946 /* Attach the constraint to the type declaration. */
25949 }
25951 /* Given type ARG, return std::initializer_list<ARG>. */
25953 static tree
25955 {
25959 {
25963 "deducing from brace-enclosed initializer list"
25967 }
25973 }
25975 /* Replace auto in TYPE with std::initializer_list<auto>. */
25977 static tree
25979 {
25986 }
25988 /* Hash traits for hashing possibly constrained 'auto'
25989 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
25992 {
25995 };
25997 /* Hash the 'auto' T. */
25999 inline hashval_t
26001 {
26003 /* Matching constrained-type-specifiers denote the same template
26004 parameter, so hash the constraint. */
26006 else
26007 /* But unconstrained autos are all separate, so just hash the pointer. */
26009 }
26011 /* Compare two 'auto's. */
26015 {
26022 /* Two unconstrained autos are distinct. */
26027 }
26029 /* for_each_template_parm callback for extract_autos: if t is a (possibly
26030 constrained) auto, add it to the vector. */
26032 static int
26034 {
26037 {
26038 /* All the autos were built with index 0; fix that up now. */
26042 /* If this is a repeated constrained-type-specifier, use the index we
26043 chose before. */
26045 else
26046 {
26047 /* Otherwise this is new, so use the current count. */
26050 }
26052 }
26054 /* Always keep walking. */
26056 }
26058 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
26059 says they can appear anywhere in the type. */
26061 static tree
26063 {
26072 {
26077 }
26080 }
26082 /* The stem for deduction guide names. */
26085 /* Return the name for a deduction guide for class template TMPL. */
26087 tree
26089 {
26100 }
26102 /* True if NAME is the name of a deduction guide. */
26104 bool
26106 {
26111 }
26113 /* True if FN is a deduction guide. */
26115 bool
26117 {
26122 }
26124 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
26126 bool
26128 {
26135 }
26137 /* True if FN is a guide generated from a constructor template. */
26139 bool
26141 {
26149 }
26151 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
26152 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
26153 template parameter types. Note that the handling of template template
26154 parameters relies on current_template_parms being set appropriately for the
26155 new template. */
26157 static tree
26160 {
26166 tree newtype;
26169 {
26176 }
26177 else
26178 {
26181 {
26182 // Substitute once to fix references to other template parameters.
26185 // Now substitute again to reduce the level of the auto.
26188 }
26189 else
26192 }
26194 tree newdecl
26199 tree newidx;
26202 {
26212 {
26217 // First create a copy (ttargs) of tsubst_args with an
26218 // additional level for the template template parameter's own
26219 // template parameters (ttparms).
26220 tree ttparms = (INNERMOST_TEMPLATE_PARMS
26228 // Substitute ttargs into ttparms to fix references to
26229 // other template parameters.
26232 // Now substitute again with args based on tparms, to reduce
26233 // the level of the ttparms.
26236 complain);
26237 // Finally, tack the adjusted parms onto tparms.
26239 current_template_parms);
26241 }
26242 }
26243 else
26244 {
26246 tree newconst
26258 }
26261 }
26263 /* Returns a C++17 class deduction guide template based on the constructor
26264 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
26265 guide, or REFERENCE_TYPE for an implicit copy/move guide. */
26267 static tree
26269 {
26273 location_t loc;
26277 {
26281 {
26284 }
26285 else
26295 }
26296 else
26297 {
26301 fn_tmpl
26311 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
26312 fully specialized args for the enclosing class. Strip those off, as
26313 the deduction guide won't have those template parameters. */
26316 /* Discard the 'this' parameter. */
26324 {
26327 /* For a member template constructor, we need to flatten the two
26328 template parameter lists into one, and then adjust the function
26329 signature accordingly. This gets...complicated. */
26332 /* For a member template we should have two levels of parms/args, one
26333 for the class and one for the constructor. We stripped
26334 specialized args for further enclosing classes above. */
26338 /* Template args for translating references to the two-level template
26339 parameters into references to the one-level template parameters we
26340 are creating. */
26345 /* Template parms for the constructor template. */
26348 /* Template parms for the class template. */
26352 /* Template parms for the deduction guide start as a copy of the
26353 template parms for the class. We set current_template_parms for
26354 lookup_template_class_1. */
26360 /* Now we need to rewrite the constructor parms to append them to the
26361 class parms. */
26363 {
26380 }
26382 /* Now we have a final set of template parms to substitute into the
26383 function signature. */
26392 }
26397 }
26400 {
26401 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
26405 }
26409 FUNCTION_DECL,
26426 }
26428 /* Deduce template arguments for the class template placeholder PTYPE for
26429 template TMPL based on the initializer INIT, and return the resulting
26430 type. */
26432 static tree
26434 tsubst_flags_t complain)
26435 {
26437 {
26438 /* We should have handled this in the caller. */
26444 }
26455 {
26458 {
26459 /* As an exception, the first phase in 16.3.1.7 (considering the
26460 initializer list as a single argument) is omitted if the
26461 initializer list consists of a single expression of type cv U,
26462 where U is a specialization of C or a class derived from a
26463 specialization of C. */
26474 }
26477 else
26479 }
26480 else
26491 /* Prune explicit deduction guides in copy-initialization context. */
26493 {
26499 {
26500 /* Found a nonconverting guide, prune the candidates. */
26507 }
26508 }
26513 {
26516 }
26519 // FIXME cache artificial deduction guides
26521 {
26522 /* Skip inherited constructors. */
26532 else
26536 }
26540 /* If this is list-initialization and the class has a list constructor, first
26541 try deducing from the list as a single argument, as [over.match.list]. */
26545 {
26549 }
26551 {
26557 {
26558 /* That didn't work, now try treating the list as a sequence of
26559 arguments. */
26562 }
26563 }
26565 /* Maybe generate an implicit deduction guide. */
26567 {
26571 /* Generate a copy guide. */
26574 /* Generate a default guide. */
26578 {
26583 }
26584 }
26587 {
26589 " of %qT, as it has no non-explicit deduction guides or "
26592 }
26594 {
26598 }
26601 {
26605 }
26608 {
26618 }
26623 }
26625 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
26626 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
26627 The CONTEXT determines the context in which auto deduction is performed
26628 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
26629 OUTER_TARGS are used during template argument deduction
26630 (context == adc_unify) to properly substitute the result, and is ignored
26631 in other contexts.
26633 For partial-concept-ids, extra args may be appended to the list of deduced
26634 template arguments prior to determining constraint satisfaction. */
26636 tree
26640 {
26641 tree targs;
26648 /* Defining a subset of type-dependent expressions that we can deduce
26649 from ahead of time isn't worth the trouble. */
26652 /* Similarly, we can't deduce from another undeduced decl. */
26657 /* C++17 class template argument deduction. */
26661 /* Nothing we can do with this, even in deduction context. */
26664 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
26665 with either a new invented type template parameter U or, if the
26666 initializer is a braced-init-list (8.5.4), with
26667 std::initializer_list<U>. */
26669 {
26674 else
26675 {
26677 {
26681 "for deduction to %<std::initializer_list%>, use copy-"
26683 }
26685 }
26686 }
26697 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
26698 and initializer has array type, deduce cv-qualified array type. */
26700 complain);
26702 {
26711 {
26715 }
26716 }
26717 else
26718 {
26720 tree tparms;
26724 else
26725 {
26729 }
26736 {
26738 /* Try again at instantiation time. */
26742 /* If type is error_mark_node a diagnostic must have been
26743 emitted by now. Also, having a mention to '<type error>'
26744 in the diagnostic is not really useful to the user. */
26745 {
26749 else
26754 }
26756 }
26757 }
26759 /* Check any placeholder constraints against the deduced type. */
26762 {
26763 /* Use the deduced type to check the associated constraints. If we
26764 have a partial-concept-id, rebuild the argument list so that
26765 we check using the extra arguments. */
26769 {
26772 }
26773 else
26776 {
26778 {
26780 {
26798 }
26800 }
26802 }
26803 }
26809 }
26811 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
26812 result. */
26814 tree
26816 {
26818 {
26824 /* In an abbreviated function template we didn't know we were dealing
26825 with a function template when we saw the auto return type, so update
26826 it to have the correct level. */
26828 }
26830 }
26832 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
26833 'decltype(auto)' or a deduced class template. */
26835 bool
26837 {
26843 else
26845 }
26847 /* for_each_template_parm callback for type_uses_auto. */
26849 int
26851 {
26853 }
26855 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
26856 a use of `auto'. Returns NULL_TREE otherwise. */
26858 tree
26860 {
26864 {
26865 /* The Concepts TS allows multiple autos in one type-specifier; just
26866 return the first one we find, do_auto_deduction will collect all of
26867 them. */
26871 else
26873 }
26874 else
26876 }
26878 /* Report ill-formed occurrences of auto types in ARGUMENTS. If
26879 concepts are enabled, auto is acceptable in template arguments, but
26880 only when TEMPL identifies a template class. Return TRUE if any
26881 such errors were reported. */
26883 bool
26885 {
26886 /* If there were previous errors, nevermind. */
26890 /* If TMPL is an identifier, we're parsing and we can't tell yet
26891 whether TMPL is supposed to be a type, a function or a variable.
26892 We'll only be able to tell during template substitution, so we
26893 expect to be called again then. If concepts are enabled and we
26894 know we have a type, we're ok. */
26902 /* Quickly search for any occurrences of auto; usually there won't
26903 be any, and then we'll avoid allocating the vector. */
26911 {
26916 }
26919 }
26921 /* For a given template T, return the vector of typedefs referenced
26922 in T for which access check is needed at T instantiation time.
26923 T is either a FUNCTION_DECL or a RECORD_TYPE.
26924 Those typedefs were added to T by the function
26925 append_type_to_template_for_access_check. */
26929 {
26930 tree ti;
26941 {
26946 }
26949 }
26951 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
26952 tied to T. That list of typedefs will be access checked at
26953 T instantiation time.
26954 T is either a FUNCTION_DECL or a RECORD_TYPE.
26955 TYPE_DECL is a TYPE_DECL node representing a typedef.
26956 SCOPE is the scope through which TYPE_DECL is accessed.
26957 LOCATION is the location of the usage point of TYPE_DECL.
26959 This function is a subroutine of
26960 append_type_to_template_for_access_check. */
26962 static void
26964 tree type_decl,
26965 tree scope,
26966 location_t location)
26967 {
26968 qualified_typedef_usage_t typedef_usage;
26969 tree ti;
26976 && type_decl
26990 }
26992 /* Append TYPE_DECL to the template TEMPL.
26993 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
26994 At TEMPL instanciation time, TYPE_DECL will be checked to see
26995 if it can be accessed through SCOPE.
26996 LOCATION is the location of the usage point of TYPE_DECL.
26998 e.g. consider the following code snippet:
27000 class C
27001 {
27002 typedef int myint;
27003 };
27005 template<class U> struct S
27006 {
27007 C::myint mi; // <-- usage point of the typedef C::myint
27008 };
27010 S<char> s;
27012 At S<char> instantiation time, we need to check the access of C::myint
27013 In other words, we need to check the access of the myint typedef through
27014 the C scope. For that purpose, this function will add the myint typedef
27015 and the scope C through which its being accessed to a list of typedefs
27016 tied to the template S. That list will be walked at template instantiation
27017 time and access check performed on each typedefs it contains.
27018 Note that this particular code snippet should yield an error because
27019 myint is private to C. */
27021 void
27023 tree type_decl,
27024 tree scope,
27025 location_t location)
27026 {
27032 /* Make sure we don't append the type to the template twice. */
27039 }
27041 /* Convert the generic type parameters in PARM that match the types given in the
27042 range [START_IDX, END_IDX) from the current_template_parms into generic type
27043 packs. */
27045 tree
27047 {
27058 {
27059 /* Create a distinct parameter pack type from the current parm and add it
27060 to the replacement args to tsubst below into the generic function
27061 parameter. */
27076 }
27082 /* If there are more levels then build up the replacement with the outer
27083 template parms. */
27087 replacement);
27090 }
27092 /* Entries in the decl_constraint hash table. */
27094 {
27095 tree decl;
27096 tree ci;
27097 };
27099 /* Hashing function and equality for constraint entries. */
27101 {
27103 {
27105 }
27108 {
27110 }
27111 };
27113 /* A mapping from declarations to constraint information. Note that
27114 both templates and their underlying declarations are mapped to the
27115 same constraint information.
27117 FIXME: This is defined in pt.c because garbage collection
27118 code is not being generated for constraint.cc. */
27122 /* Returns the template constraints of declaration T. If T is not
27123 constrained, return NULL_TREE. Note that T must be non-null. */
27125 tree
27127 {
27138 else
27140 }
27142 /* Associate the given constraint information CI with the declaration
27143 T. If T is a template, then the constraints are associated with
27144 its underlying declaration. Don't build associations if CI is
27145 NULL_TREE. */
27147 void
27149 {
27161 }
27163 /* Remove the associated constraints of the declaration T. */
27165 void
27167 {
27176 }
27178 /* Memoized satisfaction results for declarations. This
27179 maps the pair (constraint_info, arguments) to the result computed
27180 by constraints_satisfied_p. */
27183 {
27184 tree ci;
27185 tree args;
27186 tree result;
27187 };
27189 /* Hashing function and equality for constraint entries. */
27192 {
27194 {
27197 }
27200 {
27202 }
27203 };
27205 /* Memoized satisfaction results for concept checks. */
27208 {
27209 tree tmpl;
27210 tree args;
27211 tree result;
27212 };
27214 /* Hashing function and equality for constraint entries. */
27217 {
27219 {
27221 }
27224 {
27229 }
27230 };
27235 /* Search for a memoized satisfaction result. Returns one of the
27236 truth value nodes if previously memoized, or NULL_TREE otherwise. */
27238 tree
27240 {
27245 else
27247 }
27249 /* Memoize the result of a satisfication test. Returns the saved result. */
27251 tree
27253 {
27260 }
27262 /* Search for a memoized satisfaction result for a concept. */
27264 tree
27266 {
27271 else
27273 }
27275 /* Memoize the result of a concept check. Returns the saved result. */
27277 tree
27279 {
27286 }
27290 /* Returns a prior concept specialization. This returns the substituted
27291 and normalized constraints defined by the concept. */
27293 tree
27295 {
27300 else
27302 }
27304 /* Save a concept expansion for later. */
27306 tree
27308 {
27315 }
27317 static hashval_t
27319 {
27328 }
27330 /* Compare the constraints of two subsumption entries. The LEFT1 and
27331 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
27332 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
27334 static bool
27336 {
27344 }
27346 /* Key/value pair for learning and memoizing subsumption results. This
27347 associates a pair of check constraints (including arguments) with
27348 a boolean value indicating the result. */
27351 {
27352 tree t1;
27353 tree t2;
27355 };
27357 /* Hashing function and equality for constraint entries. */
27360 {
27362 {
27364 }
27367 {
27372 }
27373 };
27377 /* Search for a previously cached subsumption result. */
27381 {
27386 else
27388 }
27390 /* Save a subsumption result. */
27392 bool
27394 {
27401 }
27403 /* Set up the hash table for constraint association. */
27405 void
27407 {
27416 }
27418 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
27419 0..N-1. */
27421 void
27423 {
27426 integer_type_node,
27427 NULL_TREE),
27431 }
27433 /* Set up the hash tables for template instantiations. */
27435 void
27437 {
27443 }
27445 /* Print stats about the template hash tables for -fstats. */
27447 void
27449 {
27458 }
27460 #if CHECKING_P
27464 /* Verify that build_non_dependent_expr () works, for various expressions,
27465 and that location wrappers don't affect the results. */
27467 static void
27469 {
27472 /* Verify constants, without and with location wrappers. */
27489 }
27491 /* Verify that type_dependent_expression_p () works correctly, even
27492 in the presence of location wrapper nodes. */
27494 static void
27496 {
27501 /* If no templates are involved, nothing is type-dependent. */
27507 /* Within a template, an unresolved name is always type-dependent. */
27510 /* Ensure it copes with NULL_TREE and errors. */
27514 /* A USING_DECL in a template should be type-dependent, even if wrapped
27515 with a location wrapper (PR c++/83799). */
27524 }
27526 /* Run all of the selftests within this file. */
27528 void
27530 {
27533 }