| blob | 7fecc03f6cc3aff1a7e582f06207693c73952006 |
1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2019 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 };
158 tree);
212 location_t);
224 /* Make the current scope suitable for access checking when we are
225 processing T. T can be FUNCTION_DECL for instantiated function
226 template, VAR_DECL for static member variable, or TYPE_DECL for
227 alias template (needed by instantiate_decl). */
229 void
231 {
239 else
243 {
246 }
247 }
249 /* Restore the scope set up by push_access_scope. T is the node we
250 are processing. */
252 void
254 {
260 else
262 }
264 /* Do any processing required when DECL (a member template
265 declaration) is finished. Returns the TEMPLATE_DECL corresponding
266 to DECL, unless it is a specialization, in which case the DECL
267 itself is returned. */
269 tree
271 {
278 {
279 tree type;
287 {
291 }
293 }
298 {
300 {
303 }
304 else
306 }
307 else
312 }
314 /* Create a template info node. */
316 tree
318 {
323 }
325 /* Return the template info node corresponding to T, whatever T is. */
327 tree
329 {
351 }
353 /* Returns the template nesting level of the indicated class TYPE.
355 For example, in:
356 template <class T>
357 struct A
358 {
359 template <class U>
360 struct B {};
361 };
363 A<T>::B<U> has depth two, while A<T> has depth one.
364 Both A<T>::B<int> and A<int>::B<U> have depth one, if
365 they are instantiations, not specializations.
367 This function is guaranteed to return 0 if passed NULL_TREE so
368 that, for example, `template_class_depth (current_class_type)' is
369 always safe. */
371 int
373 {
377 {
388 else
390 }
393 }
395 /* Return TRUE if NODE instantiates a template that has arguments of
396 its own, be it directly a primary template or indirectly through a
397 partial specializations. */
398 static bool
400 {
412 /* So now we know we have a specialization, but it could be a full
413 or a partial specialization. To tell which, compare the depth of
414 its template arguments with those of its context. */
423 }
425 /* Subroutine of maybe_begin_member_template_processing.
426 Returns true if processing DECL needs us to push template parms. */
428 static bool
430 {
436 }
438 /* Subroutine of maybe_begin_member_template_processing.
439 Push the template parms in PARMS, starting from LEVELS steps into the
440 chain, and ending at the beginning, since template parms are listed
441 innermost first. */
443 static void
445 {
453 current_template_parms
459 NULL);
461 {
470 {
477 /* Push the CONST_DECL. */
483 }
484 }
485 }
487 /* Restore the template parameter context for a member template, a
488 friend template defined in a class definition, or a non-template
489 member of template class. */
491 void
493 {
494 tree parms;
499 {
502 /* Disregard full specializations (c++/60999). */
505 }
508 {
513 {
516 }
519 }
521 /* Remember how many levels of template parameters we pushed so that
522 we can pop them later. */
524 }
526 /* Undo the effects of maybe_begin_member_template_processing. */
528 void
530 {
539 {
543 }
544 }
546 /* Return a new template argument vector which contains all of ARGS,
547 but has as its innermost set of arguments the EXTRA_ARGS. */
549 static tree
551 {
552 tree new_args;
570 }
572 /* Like add_to_template_args, but only the outermost ARGS are added to
573 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
574 (EXTRA_ARGS) levels are added. This function is used to combine
575 the template arguments from a partial instantiation with the
576 template arguments used to attain the full instantiation from the
577 partial instantiation. */
579 tree
581 {
582 tree new_args;
584 /* If there are more levels of EXTRA_ARGS than there are ARGS,
585 something very fishy is going on. */
588 /* If *all* the new arguments will be the EXTRA_ARGS, just return
589 them. */
593 /* For the moment, we make ARGS look like it contains fewer levels. */
598 /* Now, we restore ARGS to its full dimensions. */
602 }
604 /* Return the N levels of innermost template arguments from the ARGS. */
606 tree
608 {
609 tree new_args;
615 /* If N is 1, just return the innermost set of template arguments. */
619 /* If we're not removing anything, just return the arguments we were
620 given. */
626 /* Make a new set of arguments, not containing the outer arguments. */
633 }
635 /* The inverse of get_innermost_template_args: Return all but the innermost
636 EXTRA_LEVELS levels of template arguments from the ARGS. */
638 static tree
640 {
641 tree new_args;
647 /* If N is 1, just return the outermost set of template arguments. */
651 /* If we're not removing anything, just return the arguments we were
652 given. */
657 /* Make a new set of arguments, not containing the inner arguments. */
664 }
666 /* We've got a template header coming up; push to a new level for storing
667 the parms. */
669 void
671 {
672 /* We use a non-tag-transparent scope here, which causes pushtag to
673 put tags in this scope, rather than in the enclosing class or
674 namespace scope. This is the right thing, since we want
675 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
676 global template class, push_template_decl handles putting the
677 TEMPLATE_DECL into top-level scope. For a nested template class,
678 e.g.:
680 template <class T> struct S1 {
681 template <class T> struct S2 {};
682 };
684 pushtag contains special code to insert the TEMPLATE_DECL for S2
685 at the right scope. */
691 /* Add a dummy parameter level while we process the parameter list. */
692 current_template_parms
695 current_template_parms);
696 }
698 /* This routine is called when a specialization is declared. If it is
699 invalid to declare a specialization here, an error is reported and
700 false is returned, otherwise this routine will return true. */
702 static bool
704 {
707 /* [temp.expl.spec]
709 An explicit specialization shall be declared in the namespace of
710 which the template is a member, or, for member templates, in the
711 namespace of which the enclosing class or enclosing class
712 template is a member. An explicit specialization of a member
713 function, member class or static data member of a class template
714 shall be declared in the namespace of which the class template
715 is a member. */
717 {
720 }
722 /* [temp.expl.spec]
724 In an explicit specialization declaration for a member of a class
725 template or a member template that appears in namespace scope,
726 the member template and some of its enclosing class templates may
727 remain unspecialized, except that the declaration shall not
728 explicitly specialize a class member template if its enclosing
729 class templates are not explicitly specialized as well. */
731 {
734 }
737 }
739 /* We've just seen template <>. */
741 bool
743 {
747 }
749 /* Called at then end of processing a declaration preceded by
750 template<>. */
752 void
754 {
757 }
759 /* Any template <>'s that we have seen thus far are not referring to a
760 function specialization. */
762 void
764 {
767 }
769 /* We've just seen a template header. If SPECIALIZATION is nonzero,
770 it was of the form template <>. */
772 static void
774 {
776 template_header_count++;
777 }
779 /* We're beginning an explicit instantiation. */
781 void
783 {
786 }
789 void
791 {
794 }
796 /* An explicit specialization or partial specialization of TMPL is being
797 declared. Check that the namespace in which the specialization is
798 occurring is permissible. Returns false iff it is invalid to
799 specialize TMPL in the current namespace. */
801 static bool
803 {
806 /* [tmpl.expl.spec]
808 An explicit specialization shall be declared in a namespace enclosing the
809 specialized template. An explicit specialization whose declarator-id is
810 not qualified shall be declared in the nearest enclosing namespace of the
811 template, or, if the namespace is inline (7.3.1), any namespace from its
812 enclosing namespace set. */
815 {
818 }
821 /* Same or enclosing namespace. */
823 else
824 {
825 auto_diagnostic_group d;
831 }
832 }
834 /* SPEC is an explicit instantiation. Check that it is valid to
835 perform this explicit instantiation in the current namespace. */
837 static void
839 {
840 tree ns;
842 /* DR 275: An explicit instantiation shall appear in an enclosing
843 namespace of its template. */
849 }
851 // Returns the type of a template specialization only if that
852 // specialization needs to be defined. Otherwise (e.g., if the type has
853 // already been defined), the function returns NULL_TREE.
854 static tree
856 {
857 // An implicit instantiation of an incomplete type implies
858 // the definition of a new class template.
859 //
860 // template<typename T>
861 // struct S;
862 //
863 // template<typename T>
864 // struct S<T*>;
865 //
866 // Here, S<T*> is an implicit instantiation of S whose type
867 // is incomplete.
871 // It can also be the case that TYPE is a completed specialization.
872 // Continuing the previous example, suppose we also declare:
873 //
874 // template<typename T>
875 // requires Integral<T>
876 // struct S<T*>;
877 //
878 // Here, S<T*> refers to the specialization S<T*> defined
879 // above. However, we need to differentiate definitions because
880 // we intend to define a new partial specialization. In this case,
881 // we rely on the fact that the constraints are different for
882 // this declaration than that above.
883 //
884 // Note that we also get here for injected class names and
885 // late-parsed template definitions. We must ensure that we
886 // do not create new type declarations for those cases.
888 {
892 // If there are no template parameters, this cannot be a new
893 // partial template specializtion?
897 // The injected-class-name is not a new partial specialization.
901 // If the constraints are not the same as those of the primary
902 // then, we can probably create a new specialization.
906 {
910 }
912 // Also, if there's a pre-existing specialization with matching
913 // constraints, then this also isn't new.
916 {
924 }
926 // Create a new type node (and corresponding type decl)
927 // for the newly declared specialization.
932 /* We only need a separate type node for storing the definition of this
933 partial specialization; uses of S<T*> are unconstrained, so all are
934 equivalent. So keep TYPE_CANONICAL the same. */
937 // Build the corresponding type decl.
943 }
946 }
948 /* The TYPE is being declared. If it is a template type, that means it
949 is a partial specialization. Do appropriate error-checking. */
951 tree
953 {
954 tree context;
959 /* A lambda that appears in specialization context is not itself a
960 specialization. */
965 {
969 }
974 {
980 else
983 }
985 {
986 /* This is for ordinary explicit specialization and partial
987 specialization of a template class such as:
989 template <> class C<int>;
991 or:
993 template <class T> class C<T*>;
995 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
998 {
1005 {
1010 }
1011 }
1017 /* Trying to define a specialization either without a template<> header
1018 or in an inappropriate place. We've already given an error, so just
1019 bail now so we don't actually define the specialization. */
1021 }
1027 {
1028 /* This is for an explicit specialization of member class
1029 template according to [temp.expl.spec/18]:
1031 template <> template <class U> class C<int>::D;
1033 The context `C<int>' must be an implicit instantiation.
1034 Otherwise this is just a member class template declared
1035 earlier like:
1037 template <> class C<int> { template <class U> class D; };
1038 template <> template <class U> class C<int>::D;
1040 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1041 while in the second case, `C<int>::D' is a primary template
1042 and `C<T>::D' may not exist. */
1046 {
1047 tree t;
1052 {
1055 type))
1058 }
1060 /* Check for invalid specialization after instantiation:
1062 template <> template <> class C<int>::D<int>;
1063 template <> template <class U> class C<int>::D; */
1067 {
1071 {
1072 /* We already have a full specialization of this partial
1073 instantiation, or a full specialization has been
1074 looked up but not instantiated. Reassign it to the
1075 new member specialization template. */
1076 spec_entry elt;
1089 spec_entry **slot
1094 }
1095 else
1096 /* But if we've had an implicit instantiation, that's a
1097 problem ([temp.expl.spec]/6). */
1100 }
1102 /* Mark TYPE as a specialization. And as a result, we only
1103 have one level of template argument for the innermost
1104 class template. */
1109 }
1110 }
1112 {
1113 /* Someday C++0x may allow for enum template specialization. */
1118 else
1119 {
1122 }
1123 }
1126 }
1128 /* Returns nonzero if we can optimize the retrieval of specializations
1129 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1130 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1134 {
1137 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1138 parameter. */
1140 /* The optimized lookup depends on the fact that the
1141 template arguments for the member function template apply
1142 purely to the containing class, which is not true if the
1143 containing class is an explicit or partial
1144 specialization. */
1148 /* It is possible to have a template that is not a member
1149 template and is not a member of a template class:
1151 template <typename T>
1152 struct S { friend A::f(); };
1154 Here, the friend function is a template, but the context does
1155 not have template information. The optimized lookup relies
1156 on having ARGS be the template arguments for both the class
1157 and the function template. */
1159 }
1161 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1162 gone through coerce_template_parms by now. */
1164 static void
1166 {
1168 {
1177 /* Allow typedefs on the type of a non-type argument, since a
1179 else
1181 }
1182 }
1184 static void
1186 {
1191 }
1193 /* Retrieve the specialization (in the sense of [temp.spec] - a
1194 specialization is either an instantiation or an explicit
1195 specialization) of TMPL for the given template ARGS. If there is
1196 no such specialization, return NULL_TREE. The ARGS are a vector of
1197 arguments, or a vector of vectors of arguments, in the case of
1198 templates with more than one level of parameters.
1200 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1201 then we search for a partial specialization matching ARGS. This
1202 parameter is ignored if TMPL is not a class template.
1204 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1205 result is a NONTYPE_ARGUMENT_PACK. */
1207 static tree
1209 {
1219 /* There should be as many levels of arguments as there are
1220 levels of parameters. */
1229 /* Lambda functions in templates aren't instantiated normally, but through
1230 tsubst_lambda_expr. */
1235 {
1236 /* The template arguments actually apply to the containing
1237 class. Find the class specialization with those
1238 arguments. */
1240 tree class_specialization
1245 /* Find the instance of TMPL. */
1248 {
1251 /* using-declarations can add base methods to the method vec,
1252 and we don't want those here. */
1255 }
1257 }
1258 else
1259 {
1261 spec_entry elt;
1270 else
1278 }
1281 }
1283 /* Like retrieve_specialization, but for local declarations. */
1285 tree
1287 {
1293 }
1295 /* Returns nonzero iff DECL is a specialization of TMPL. */
1297 int
1299 {
1300 tree t;
1303 {
1309 }
1310 else
1311 {
1320 }
1323 }
1325 /* Returns nonzero iff DECL is a specialization of friend declaration
1326 FRIEND_DECL according to [temp.friend]. */
1328 bool
1330 {
1337 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1338 of a template class, we want to check if DECL is a specialization
1339 if this. */
1343 {
1344 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1347 }
1352 /* There is nothing to do if this is not a template friend. */
1359 /* [temp.friend/6]
1360 A member of a class template may be declared to be a friend of a
1361 non-template class. In this case, the corresponding member of
1362 every specialization of the class template is a friend of the
1363 class granting friendship.
1365 For example, given a template friend declaration
1367 template <class T> friend void A<T>::f();
1369 the member function below is considered a friend
1371 template <> struct A<int> {
1372 void f();
1373 };
1375 For this type of template friend, TEMPLATE_DEPTH below will be
1376 nonzero. To determine if DECL is a friend of FRIEND, we first
1377 check if the enclosing class is a specialization of another. */
1384 {
1385 /* Next, we check the members themselves. In order to handle
1386 a few tricky cases, such as when FRIEND_DECL's are
1388 template <class T> friend void A<T>::g(T t);
1389 template <class T> template <T t> friend void A<T>::h();
1391 and DECL's are
1393 void A<int>::g(int);
1394 template <int> void A<int>::h();
1396 we need to figure out ARGS, the template arguments from
1397 the context of DECL. This is required for template substitution
1398 of `T' in the function parameter of `g' and template parameter
1399 of `h' in the above examples. Here ARGS corresponds to `int'. */
1406 {
1408 {
1411 else
1413 current_depth++;
1414 }
1416 }
1419 {
1421 tree friend_type;
1422 tree decl_type;
1423 tree friend_args_type;
1424 tree decl_args_type;
1426 /* Make sure that both DECL and FRIEND_DECL are templates or
1427 non-templates. */
1433 {
1434 /* If both are templates, check template parameter list. */
1435 tree friend_parms
1440 friend_parms))
1444 }
1445 else
1453 /* Check if return types match. */
1457 /* Check if function parameter types match, ignoring the
1458 `this' parameter. */
1467 }
1468 else
1469 {
1470 /* DECL is a TYPE_DECL */
1474 /* Make sure that both DECL and FRIEND_DECL are templates or
1475 non-templates. */
1476 is_template
1483 {
1484 tree friend_parms;
1485 /* If both are templates, check the name of the two
1486 TEMPLATE_DECL's first because is_friend didn't. */
1491 /* Now check template parameter list. */
1492 friend_parms
1495 return comp_template_parms
1497 friend_parms);
1498 }
1499 else
1502 }
1503 }
1505 }
1507 /* Register the specialization SPEC as a specialization of TMPL with
1508 the indicated ARGS. IS_FRIEND indicates whether the specialization
1509 is actually just a friend declaration. ATTRLIST is the list of
1510 attributes that the specialization is declared with or NULL when
1511 it isn't. Returns SPEC, or an equivalent prior declaration, if
1512 available.
1514 We also store instantiations of field packs in the hash table, even
1515 though they are not themselves templates, to make lookup easier. */
1517 static tree
1519 hashval_t hash)
1520 {
1521 tree fn;
1523 spec_entry elt;
1531 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1532 register it; we want the corresponding TEMPLATE_DECL instead.
1533 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1534 the more obvious `uses_template_parms (spec)' to avoid problems
1535 with default function arguments. In particular, given
1536 something like this:
1538 template <class T> void f(T t1, T t = T())
1540 the default argument expression is not substituted for in an
1541 instantiation unless and until it is actually needed. */
1545 /* We don't put these specializations in the hash table, but we might
1546 want to give an error about a mismatch. */
1548 else
1549 {
1557 slot =
1561 else
1563 }
1565 /* We can sometimes try to re-register a specialization that we've
1566 already got. In particular, regenerate_decl_from_template calls
1567 duplicate_decls which will update the specialization list. But,
1568 we'll still get called again here anyhow. It's more convenient
1569 to simply allow this than to try to prevent it. */
1573 {
1575 {
1578 {
1580 fn);
1582 }
1583 else
1584 {
1585 tree clone;
1586 /* This situation should occur only if the first
1587 specialization is an implicit instantiation, the
1588 second is an explicit specialization, and the
1589 implicit instantiation has not yet been used. That
1590 situation can occur if we have implicitly
1591 instantiated a member function and then specialized
1592 it later.
1594 We can also wind up here if a friend declaration that
1595 looked like an instantiation turns out to be a
1596 specialization:
1598 template <class T> void foo(T);
1599 class S { friend void foo<>(int) };
1600 template <> void foo(int);
1602 We transform the existing DECL in place so that any
1603 pointers to it become pointers to the updated
1604 declaration.
1606 If there was a definition for the template, but not
1607 for the specialization, we want this to look as if
1608 there were no definition, and vice versa. */
1611 /* The call to duplicate_decls will have applied
1612 [temp.expl.spec]:
1614 An explicit specialization of a function template
1615 is inline only if it is explicitly declared to be,
1616 and independently of whether its function template
1617 is.
1619 to the primary function; now copy the inline bits to
1620 the various clones. */
1622 {
1629 }
1633 }
1634 }
1636 {
1639 /* We've already complained in duplicate_decls. */
1643 /* Dup decl failed, but this is a new definition. Set the
1644 line number so any errors match this new
1645 definition. */
1649 }
1650 }
1654 /* A specialization must be declared in the same namespace as the
1655 template it is specializing. */
1661 {
1670 /* If TMPL is a forward declaration of a template function, keep a list
1671 of all specializations in case we need to reassign them to a friend
1672 template later in tsubst_friend_function.
1674 Also keep a list of all variable template instantiations so that
1675 process_partial_specialization can check whether a later partial
1676 specialization would have used it. */
1679 }
1682 }
1684 /* Returns true iff two spec_entry nodes are equivalent. */
1688 bool
1690 {
1697 /* tmpl could be a FIELD_DECL for a capture pack. */
1701 {
1702 /* Partial specializations of a variable template can be distinguished by
1703 constraints. */
1707 }
1711 }
1713 /* Returns a hash for a template TMPL and template arguments ARGS. */
1715 static hashval_t
1717 {
1720 }
1722 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1723 ignoring SPEC. */
1725 hashval_t
1727 {
1729 }
1731 /* Recursively calculate a hash value for a template argument ARG, for use
1732 in the hash tables of template specializations. */
1734 hashval_t
1736 {
1756 {
1764 {
1769 }
1791 {
1795 {
1798 }
1800 }
1804 {
1807 }
1818 val = iterative_hash_template_arg
1830 val);
1832 val);
1841 /* [temp.over.link] Two lambda-expressions are never considered
1842 equivalent.
1844 So just hash the closure type. */
1855 /* Now hash operands as usual. */
1859 {
1862 {
1866 }
1868 call_expr_arg_iterator ai;
1873 }
1877 }
1880 {
1883 {
1884 // We want an alias specialization that survived strip_typedefs
1885 // to hash differently from its TYPE_CANONICAL, to avoid hash
1886 // collisions that compare as different in template_args_equal.
1887 // These could be dependent specializations that strip_typedefs
1888 // left alone, or untouched specializations because
1889 // coerce_template_parms returns the unconverted template
1890 // arguments if it sees incomplete argument packs.
1893 }
1896 val);
1899 /* Otherwise just compare the types during lookup. */
1908 {
1913 }
1914 }
1917 }
1919 /* Unregister the specialization SPEC as a specialization of TMPL.
1920 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1921 if the SPEC was listed as a specialization of TMPL.
1923 Note that SPEC has been ggc_freed, so we can't look inside it. */
1925 bool
1927 {
1929 spec_entry elt;
1937 {
1942 }
1945 }
1947 /* Like register_specialization, but for local declarations. We are
1948 registering SPEC, an instantiation of TMPL. */
1950 void
1952 {
1955 }
1957 /* TYPE is a class type. Returns true if TYPE is an explicitly
1958 specialized class. */
1960 bool
1962 {
1966 }
1968 /* Print the list of functions at FNS, going through all the overloads
1969 for each element of the list. Alternatively, FNS cannot be a
1970 TREE_LIST, in which case it will be printed together with all the
1971 overloads.
1973 MORE and *STR should respectively be FALSE and NULL when the function
1974 is called from the outside. They are used internally on recursive
1975 calls. print_candidates manages the two parameters and leaves NULL
1976 in *STR when it ends. */
1978 static void
1980 {
1984 else
1986 {
1992 {
1995 else
1998 }
2000 }
2001 }
2003 /* Print the list of candidate FNS in an error message. FNS can also
2004 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
2006 void
2008 {
2012 }
2014 /* Get a (possibly) constrained template declaration for the
2015 purpose of ordering candidates. */
2016 static tree
2018 {
2024 }
2026 /* Among candidates having the same signature, return the
2027 most constrained or NULL_TREE if there is no best candidate.
2028 If the signatures of candidates vary (e.g., template
2029 specialization vs. member function), then there can be no
2030 most constrained.
2032 Note that we don't compare constraints on the functions
2033 themselves, but rather those of their templates. */
2034 static tree
2036 {
2037 // Try to find the best candidate in a first pass.
2040 {
2047 }
2049 // Verify that the champ is better than previous candidates.
2054 }
2057 }
2060 /* Returns the template (one of the functions given by TEMPLATE_ID)
2061 which can be specialized to match the indicated DECL with the
2062 explicit template args given in TEMPLATE_ID. The DECL may be
2063 NULL_TREE if none is available. In that case, the functions in
2064 TEMPLATE_ID are non-members.
2066 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2067 specialization of a member template.
2069 The TEMPLATE_COUNT is the number of references to qualifying
2070 template classes that appeared in the name of the function. See
2071 check_explicit_specialization for a more accurate description.
2073 TSK indicates what kind of template declaration (if any) is being
2074 declared. TSK_TEMPLATE indicates that the declaration given by
2075 DECL, though a FUNCTION_DECL, has template parameters, and is
2076 therefore a template function.
2078 The template args (those explicitly specified and those deduced)
2079 are output in a newly created vector *TARGS_OUT.
2081 If it is impossible to determine the result, an error message is
2082 issued. The error_mark_node is returned to indicate failure. */
2084 static tree
2086 tree decl,
2090 tmpl_spec_kind tsk)
2091 {
2092 tree fns;
2093 tree targs;
2094 tree explicit_targs;
2097 /* A TREE_LIST of templates of which DECL may be a specialization.
2098 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2099 corresponding TREE_PURPOSE is the set of template arguments that,
2100 when used to instantiate the template, would produce a function
2101 with the signature of DECL. */
2111 /* We shouldn't be specializing a member template of an
2112 unspecialized class template; we already gave an error in
2113 check_specialization_scope, now avoid crashing. */
2117 {
2120 }
2128 /* Check for baselinks. */
2133 {
2137 }
2139 {
2142 }
2144 /* Count the number of template headers specified for this
2145 specialization. */
2155 {
2158 tf_warning_or_error,
2162 }
2164 {
2168 {
2169 tree decl_arg_types;
2170 tree fn_arg_types;
2171 tree insttype;
2173 /* In case of explicit specialization, we need to check if
2174 the number of template headers appearing in the specialization
2175 is correct. This is usually done in check_explicit_specialization,
2176 but the check done there cannot be exhaustive when specializing
2177 member functions. Consider the following code:
2179 template <> void A<int>::f(int);
2180 template <> template <> void A<int>::f(int);
2182 Assuming that A<int> is not itself an explicit specialization
2183 already, the first line specializes "f" which is a non-template
2184 member function, whilst the second line specializes "f" which
2185 is a template member function. So both lines are syntactically
2186 correct, and check_explicit_specialization does not reject
2187 them.
2189 Here, we can do better, as we are matching the specialization
2190 against the declarations. We count the number of template
2191 headers, and we check if they match TEMPLATE_COUNT + 1
2192 (TEMPLATE_COUNT is the number of qualifying template classes,
2193 plus there must be another header for the member template
2194 itself).
2196 Notice that if header_count is zero, this is not a
2197 specialization but rather a template instantiation, so there
2198 is no check we can perform here. */
2202 /* Check that the number of template arguments at the
2203 innermost level for DECL is the same as for FN. */
2211 /* DECL might be a specialization of FN. */
2215 /* For a non-static member function, we need to make sure
2216 that the const qualification is the same. Since
2217 get_bindings does not try to merge the "this" parameter,
2218 we must do the comparison explicitly. */
2220 {
2225 /* And the ref-qualification. */
2229 }
2231 /* Skip the "this" parameter and, for constructors of
2232 classes with virtual bases, the VTT parameter. A
2233 full specialization of a constructor will have a VTT
2234 parameter, but a template never will. */
2235 decl_arg_types
2237 fn_arg_types
2240 /* Function templates cannot be specializations; there are
2241 no partial specializations of functions. Therefore, if
2242 the type of DECL does not match FN, there is no
2243 match.
2245 Note that it should never be the case that we have both
2246 candidates added here, and for regular member functions
2247 below. */
2249 {
2253 }
2255 /* See whether this function might be a specialization of this
2256 template. Suppress access control because we might be trying
2257 to make this specialization a friend, and we have already done
2258 access control for the declaration of the specialization. */
2264 /* We cannot deduce template arguments that when used to
2265 specialize TMPL will produce DECL. */
2269 /* We deduced something involving 'auto', which isn't a valid
2270 template argument. */
2273 /* Remove, from the set of candidates, all those functions
2274 whose constraints are not satisfied. */
2278 // Then, try to form the new function type.
2282 fn_arg_types
2287 /* Save this template, and the arguments deduced. */
2289 }
2291 /* FN is an ordinary member function, and we need a
2292 specialization of a member template. */
2293 ;
2295 /* We can get IDENTIFIER_NODEs here in certain erroneous
2296 cases. */
2297 ;
2299 /* This is just an ordinary non-member function. Nothing can
2300 be a specialization of that. */
2301 ;
2303 /* Cannot specialize functions that are created implicitly. */
2304 ;
2305 else
2306 {
2307 tree decl_arg_types;
2309 /* This is an ordinary member function. However, since
2310 we're here, we can assume its enclosing class is a
2311 template class. For example,
2313 template <typename T> struct S { void f(); };
2314 template <> void S<int>::f() {}
2316 Here, S<int>::f is a non-template, but S<int> is a
2317 template class. If FN has the same type as DECL, we
2318 might be in business. */
2321 /* Its enclosing class is an explicit specialization
2322 of a template class. This is not a candidate. */
2327 /* The return types differ. */
2330 /* Adjust the type of DECL in case FN is a static member. */
2337 decl_arg_types))
2345 // If the deduced arguments do not satisfy the constraints,
2346 // this is not a candidate.
2350 // Add the candidate.
2352 }
2353 }
2356 {
2357 /* We have:
2359 [temp.expl.spec]
2361 It is possible for a specialization with a given function
2362 signature to be instantiated from more than one function
2363 template. In such cases, explicit specification of the
2364 template arguments must be used to uniquely identify the
2365 function template specialization being specialized.
2367 Note that here, there's no suggestion that we're supposed to
2368 determine which of the candidate templates is most
2369 specialized. However, we, also have:
2371 [temp.func.order]
2373 Partial ordering of overloaded function template
2374 declarations is used in the following contexts to select
2375 the function template to which a function template
2376 specialization refers:
2378 -- when an explicit specialization refers to a function
2379 template.
2381 So, we do use the partial ordering rules, at least for now.
2382 This extension can only serve to make invalid programs valid,
2383 so it's safe. And, there is strong anecdotal evidence that
2384 the committee intended the partial ordering rules to apply;
2385 the EDG front end has that behavior, and John Spicer claims
2386 that the committee simply forgot to delete the wording in
2387 [temp.expl.spec]. */
2390 {
2393 }
2394 }
2396 // Concepts allows multiple declarations of member functions
2397 // with the same signature. Like above, we need to rely on
2398 // on the partial ordering of those candidates to determine which
2399 // is the best.
2401 {
2403 {
2406 }
2407 }
2410 {
2415 "saw %d %<template<>%>, need %d for "
2418 else
2421 }
2425 {
2431 }
2433 /* We have one, and exactly one, match. */
2435 {
2439 /* Propagate the candidate's constraints to the declaration. */
2442 /* DECL is a re-declaration or partial instantiation of a template
2443 function. */
2446 /* It was a specialization of an ordinary member function in a
2447 template class. */
2449 }
2451 /* It was a specialization of a template. */
2454 {
2459 }
2460 else
2463 }
2465 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2466 but with the default argument values filled in from those in the
2467 TMPL_TYPES. */
2469 static tree
2471 tree tmpl_types)
2472 {
2473 tree new_spec_types;
2481 /* Substitute into the rest of the list. */
2482 new_spec_types =
2486 /* Add the default argument for this parameter. */
2489 new_spec_types);
2490 }
2492 /* DECL is an explicit specialization. Replicate default arguments
2493 from the template it specializes. (That way, code like:
2495 template <class T> void f(T = 3);
2496 template <> void f(double);
2497 void g () { f (); }
2499 works, as required.) An alternative approach would be to look up
2500 the correct default arguments at the call-site, but this approach
2501 is consistent with how implicit instantiations are handled. */
2503 static void
2505 {
2506 tree tmpl;
2507 tree spec_types;
2508 tree tmpl_types;
2509 tree new_spec_types;
2510 tree old_type;
2511 tree new_type;
2512 tree t;
2517 /* See if there's anything we need to do. */
2530 {
2531 /* Remove the this pointer, but remember the object's type for
2532 CV quals. */
2538 {
2539 /* DECL may contain more parameters than TMPL due to the extra
2540 in-charge parameter in constructors and destructors. */
2543 }
2545 {
2548 }
2549 }
2551 /* Compute the merged default arguments. */
2552 new_spec_types =
2555 /* Compute the new FUNCTION_TYPE. */
2557 {
2561 new_spec_types);
2564 /* Put the in-charge parameter back. */
2567 new_spec_types);
2571 new_spec_types);
2572 }
2573 else
2575 new_spec_types);
2581 }
2583 /* Return the number of template headers we expect to see for a definition
2584 or specialization of CTYPE or one of its non-template members. */
2586 int
2588 {
2592 {
2593 /* You're supposed to have one `template <...>' for every
2594 template class, but you don't need one for a full
2595 specialization. For example:
2597 template <class T> struct S{};
2598 template <> struct S<int> { void f(); };
2599 void S<int>::f () {}
2601 is correct; there shouldn't be a `template <>' for the
2602 definition of `S<int>::f'. */
2604 /* If CTYPE does not have template information of any
2605 kind, then it is not a template, nor is it nested
2606 within a template. */
2614 }
2617 }
2619 /* Do a simple sanity check on the template headers that precede the
2620 variable declaration DECL. */
2622 void
2624 {
2629 {
2632 "variable templates only available with "
2635 // Namespace-scope variable templates should have a template header.
2637 }
2639 {
2640 auto_diagnostic_group d;
2642 "too many template headers for %qD "
2648 "members of an explicitly specialized class are defined "
2650 }
2651 }
2653 /* An explicit specialization whose declarator-id or class-head-name is not
2654 qualified shall be declared in the nearest enclosing namespace of the
2655 template, or, if the namespace is inline (7.3.1), any namespace from its
2656 enclosing namespace set.
2658 If the name declared in the explicit instantiation is an unqualified name,
2659 the explicit instantiation shall appear in the namespace where its template
2660 is declared or, if that namespace is inline (7.3.1), any namespace from its
2661 enclosing namespace set. */
2663 void
2665 {
2670 {
2676 /* This was allowed in C++98, so only pedwarn. */
2678 "outside its namespace must use a nested-name-"
2680 }
2681 }
2683 /* Warn for a template specialization SPEC that is missing some of a set
2684 of function or type attributes that the template TEMPL is declared with.
2685 ATTRLIST is a list of additional attributes that SPEC should be taken
2686 to ultimately be declared with. */
2688 static void
2690 {
2694 /* Avoid warning if the difference between the primary and
2695 the specialization is not in one of the attributes below. */
2699 };
2701 /* Put together a list of the black listed attributes that the primary
2702 template is declared with that the specialization is not, in case
2703 it's not apparent from the most recent declaration of the primary. */
2704 pretty_printer str;
2711 auto_diagnostic_group d;
2714 spec))
2720 }
2722 /* Check to see if the function just declared, as indicated in
2723 DECLARATOR, and in DECL, is a specialization of a function
2724 template. We may also discover that the declaration is an explicit
2725 instantiation at this point.
2727 Returns DECL, or an equivalent declaration that should be used
2728 instead if all goes well. Issues an error message if something is
2729 amiss. Returns error_mark_node if the error is not easily
2730 recoverable.
2732 FLAGS is a bitmask consisting of the following flags:
2734 2: The function has a definition.
2735 4: The function is a friend.
2737 The TEMPLATE_COUNT is the number of references to qualifying
2738 template classes that appeared in the name of the function. For
2739 example, in
2741 template <class T> struct S { void f(); };
2742 void S<int>::f();
2744 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2745 classes are not counted in the TEMPLATE_COUNT, so that in
2747 template <class T> struct S {};
2748 template <> struct S<int> { void f(); }
2749 template <> void S<int>::f();
2751 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2752 invalid; there should be no template <>.)
2754 If the function is a specialization, it is marked as such via
2755 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2756 is set up correctly, and it is added to the list of specializations
2757 for that template. */
2759 tree
2761 tree decl,
2764 tree attrlist)
2765 {
2774 tmpl_spec_kind tsk;
2777 {
2780 else
2782 }
2783 else
2787 {
2790 {
2793 }
2795 {
2797 /* This could be something like:
2799 template <class T> void f(T);
2800 class S { friend void f<>(int); } */
2802 else
2803 {
2804 /* This case handles bogus declarations like template <>
2805 template <class T> void f<int>(); */
2809 declarator);
2811 }
2812 }
2816 /* The error has already been reported in
2817 check_specialization_scope. */
2823 /* Fall through. */
2836 decl);
2839 else
2843 /* Fall through. */
2849 /* In cases like template<> constexpr bool v = true;
2850 We'll give an error in check_template_variable. */
2856 else
2862 {
2863 /* This case handles bogus declarations like template <>
2864 template <class T> void f<int>(); */
2869 declarator);
2871 {
2872 /* Partial specialization of variable template. */
2876 }
2879 "non-type partial specialization %qE "
2881 else
2883 "non-class, non-variable partial specialization %qE "
2886 ok:;
2887 }
2890 /* This is a specialization of a member template, without
2891 specialization the containing class. Something like:
2893 template <class T> struct S {
2894 template <class U> void f (U);
2895 };
2896 template <> template <class U> void S<int>::f(U) {}
2898 That's a specialization -- but of the entire template. */
2904 }
2907 /* This doesn't apply to variable templates. */
2909 {
2913 {
2917 }
2918 }
2921 {
2926 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2928 {
2929 tree fns;
2934 else
2935 {
2936 /* If there is no class context, the explicit instantiation
2937 must be at namespace scope. */
2940 /* Find the namespace binding, using the declaration
2941 context. */
2945 /* If lookup fails, look for a friend declaration so we can
2946 give a better diagnostic. */
2952 {
2955 }
2956 }
2959 }
2965 {
2967 /* A specialization in class scope. This is invalid,
2968 but the error will already have been flagged by
2969 check_specialization_scope. */
2971 else
2972 {
2973 /* It's not valid to write an explicit instantiation in
2974 class scope, e.g.:
2976 class C { template void f(); }
2978 This case is caught by the parser. However, on
2979 something like:
2981 template class C { void f(); };
2983 (which is invalid) we can get here. The error will be
2984 issued later. */
2985 ;
2986 }
2989 }
2992 {
2993 // We'll match variable templates in start_decl.
2997 /* Find the list of functions in ctype that have the same
2998 name as the declared function. */
3002 {
3006 {
3007 /* From [temp.expl.spec]:
3009 If such an explicit specialization for the member
3010 of a class template names an implicitly-declared
3011 special member function (clause _special_), the
3012 program is ill-formed.
3014 Similar language is found in [temp.explicit]. */
3017 }
3020 }
3022 /* For a type-conversion operator, We might be looking for
3023 `operator int' which will be a specialization of
3024 `operator T'. Grab all the conversion operators, and
3025 then select from them. */
3030 {
3033 }
3034 else
3036 }
3038 /* Figure out what exactly is being specialized at this point.
3039 Note that for an explicit instantiation, even one for a
3040 member function, we cannot tell a priori whether the
3041 instantiation is for a member template, or just a member
3042 function of a template class. Even if a member template is
3043 being instantiated, the member template arguments may be
3044 elided if they can be deduced from the rest of the
3045 declaration. */
3048 member_specialization,
3049 template_count,
3050 tsk);
3053 /* We couldn't figure out what this declaration was
3054 specializing. */
3056 else
3057 {
3060 {
3061 auto_diagnostic_group d;
3063 "friend declaration %qD is not visible to "
3067 }
3075 {
3076 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3077 is done by do_decl_instantiation later. */
3083 {
3084 /* If TMPL is not the most general template (for
3085 example, if TMPL is a friend template that is
3086 injected into namespace scope), then there will
3087 be too many levels of TARGS. Remove some of them
3088 here. */
3090 tree new_targs;
3097 }
3100 }
3102 /* If we thought that the DECL was a member function, but it
3103 turns out to be specializing a static member function,
3104 make DECL a static member function as well. */
3110 /* If this is a specialization of a member template of a
3111 template class, we want to return the TEMPLATE_DECL, not
3112 the specialization of it. */
3114 {
3119 {
3120 tree parm;
3124 /* We want to use the argument list specified in the
3125 definition, not in the original declaration. */
3130 }
3133 }
3135 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3141 /* Inherit default function arguments from the template
3142 DECL is specializing. */
3146 /* This specialization has the same protection as the
3147 template it specializes. */
3151 /* 7.1.1-1 [dcl.stc]
3153 A storage-class-specifier shall not be specified in an
3154 explicit specialization...
3156 The parser rejects these, so unless action is taken here,
3157 explicit function specializations will always appear with
3158 global linkage.
3160 The action recommended by the C++ CWG in response to C++
3161 defect report 605 is to make the storage class and linkage
3162 of the explicit specialization match the templated function:
3164 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3165 */
3167 {
3171 /* A concept cannot be specialized. */
3173 {
3175 gen_tmpl);
3177 }
3179 /* This specialization has the same linkage and visibility as
3180 the function template it specializes. */
3183 {
3186 }
3189 {
3192 }
3193 }
3195 /* If DECL is a friend declaration, declared using an
3196 unqualified name, the namespace associated with DECL may
3197 have been set incorrectly. For example, in:
3199 template <typename T> void f(T);
3200 namespace N {
3201 struct S { friend void f<int>(int); }
3202 }
3204 we will have set the DECL_CONTEXT for the friend
3205 declaration to N, rather than to the global namespace. */
3210 /* This is not really a declaration of a specialization.
3211 It's just the name of an instantiation. But, it's not
3212 a request for an instantiation, either. */
3215 /* A specialization is not necessarily COMDAT. */
3221 /* If this is a full specialization, register it so that we can find
3222 it again. Partial specializations will be registered in
3223 process_partial_specialization. */
3225 {
3230 }
3233 /* A 'structor should already have clones. */
3239 }
3240 }
3243 }
3245 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3246 parameters. These are represented in the same format used for
3247 DECL_TEMPLATE_PARMS. */
3249 int
3251 {
3252 const_tree p1;
3253 const_tree p2;
3261 {
3273 {
3277 /* If either of the template parameters are invalid, assume
3278 they match for the sake of error recovery. */
3291 }
3292 }
3295 /* One set of parameters has more parameters lists than the
3296 other. */
3300 }
3302 /* Returns true if two template parameters are declared with
3303 equivalent constraints. */
3305 static bool
3307 {
3315 }
3317 /* Returns true when two template parameters are equivalent. */
3319 static bool
3321 {
3325 /* If either of the template parameters are invalid, assume
3326 they match for the sake of error recovery. */
3330 /* ... they declare parameters of the same kind. */
3334 /* ... one parameter was introduced by a parameter declaration, then
3335 both are. This case arises as a result of eagerly rewriting declarations
3336 during parsing. */
3340 /* ... if either declares a pack, they both do. */
3345 {
3346 /* ... if they declare non-type parameters, the types are equivalent. */
3349 }
3351 {
3352 /* ... if they declare template template parameters, their template
3353 parameter lists are equivalent. */
3356 }
3358 /* ... if they are declared with a qualified-concept name, they both
3359 are, and those names are equivalent. */
3361 }
3363 /* Returns true if two template parameters lists are equivalent.
3364 Two template parameter lists are equivalent if they have the
3365 same length and their corresponding parameters are equivalent.
3367 PARMS1 and PARMS2 are TREE_LISTs containing TREE_VECs: the
3368 data structure returned by DECL_TEMPLATE_PARMS.
3370 This is generally the same implementation as comp_template_parms
3371 except that it also the concept names and arguments used to
3372 introduce parameters. */
3374 static bool
3376 {
3383 {
3391 {
3396 }
3400 }
3406 }
3408 /* Return true if the requires-clause of the template parameter lists are
3409 equivalent and false otherwise. */
3410 static bool
3412 {
3420 }
3422 /* Returns true if two template heads are equivalent. 17.6.6.1p6:
3423 Two template heads are equivalent if their template parameter
3424 lists are equivalent and their requires clauses are equivalent.
3426 In pre-C++20, this is equivalent to calling comp_template_parms
3427 for the template parameters of TMPL1 and TMPL2. */
3429 bool
3431 {
3435 /* Don't change the matching rules for pre-C++20. */
3439 /* ... have the same number of template parameters, and their
3440 corresponding parameters are equivalent. */
3444 /* ... if either has a requires-clause, they both do and their
3445 corresponding constraint-expressions are equivalent. */
3447 }
3449 /* Determine whether PARM is a parameter pack. */
3451 bool
3453 {
3454 /* Determine if we have a non-type template parameter pack. */
3461 /* If this is a list of template parameters, we could get a
3462 TYPE_DECL or a TEMPLATE_DECL. */
3466 /* Otherwise it must be a type template parameter. */
3470 }
3472 /* Determine if T is a function parameter pack. */
3474 bool
3476 {
3480 }
3482 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3483 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3485 tree
3487 {
3494 }
3496 /* Return true iff the function parameter PARAM_DECL was expanded
3497 from the function parameter pack PACK. */
3499 bool
3501 {
3506 /* The parameter pack and its pack arguments have the same
3507 DECL_PARM_INDEX. */
3509 }
3511 /* Determine whether ARGS describes a variadic template args list,
3512 i.e., one that is terminated by a template argument pack. */
3514 static bool
3516 {
3518 tree last_parm;
3532 }
3534 /* Generate a new name for the parameter pack name NAME (an
3535 IDENTIFIER_NODE) that incorporates its */
3537 static tree
3539 {
3540 /* Munge the name to include the parameter index. */
3541 #define NUMBUF_LEN 128
3555 }
3557 /* Return true if T is a primary function, class or alias template
3558 specialization, not including the template pattern. */
3560 bool
3562 {
3578 }
3580 /* Return true if PARM is a template template parameter. */
3582 bool
3584 {
3586 }
3588 /* Return true iff PARM is a DECL representing a type template
3589 parameter. */
3591 bool
3593 {
3598 }
3600 /* Return the template parameters of T if T is a
3601 primary template instantiation, NULL otherwise. */
3603 tree
3605 {
3610 parms = INNERMOST_TEMPLATE_PARMS
3614 }
3616 /* Return the template parameters of the LEVELth level from the full list
3617 of template parameters PARMS. */
3619 tree
3621 {
3622 tree p;
3633 }
3635 /* Returns the template arguments of T if T is a template instantiation,
3636 NULL otherwise. */
3638 tree
3640 {
3648 }
3650 /* Return the argument pack elements of T if T is a template argument pack,
3651 NULL otherwise. */
3653 tree
3655 {
3661 }
3663 /* In an ARGUMENT_PACK_SELECT, the actual underlying argument that the
3664 ARGUMENT_PACK_SELECT represents. */
3666 static tree
3668 {
3672 /* If the selected argument is an expansion E, that most likely means we were
3673 called from gen_elem_of_pack_expansion_instantiation during the
3674 substituting of an argument pack (of which the Ith element is a pack
3675 expansion, where I is ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
3676 In this case, the Ith element resulting from this substituting is going to
3677 be a pack expansion, which pattern is the pattern of E. Let's return the
3678 pattern of E, and gen_elem_of_pack_expansion_instantiation will build the
3679 resulting pack expansion from it. */
3681 {
3682 /* Make sure we aren't throwing away arg info. */
3685 }
3688 }
3691 /* True iff FN is a function representing a built-in variadic parameter
3692 pack. */
3694 bool
3696 {
3706 }
3708 /* True iff CALL is a call to a function representing a built-in variadic
3709 parameter pack. */
3711 static bool
3713 {
3717 }
3719 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3721 static tree
3723 tree in_decl)
3724 {
3730 {
3732 {
3735 }
3740 }
3741 else
3742 {
3746 /* Calculate the largest value of len that won't make the size of the vec
3747 overflow an int. The compiler will exceed resource limits long before
3748 this, but it seems a decent place to diagnose. */
3752 {
3756 max);
3758 }
3766 }
3767 }
3769 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3770 CALL. */
3772 static tree
3774 tree in_decl)
3775 {
3785 }
3787 /* Structure used to track the progress of find_parameter_packs_r. */
3788 struct find_parameter_pack_data
3789 {
3790 /* TREE_LIST that will contain all of the parameter packs found by
3791 the traversal. */
3794 /* Set of AST nodes that have been visited by the traversal. */
3797 /* True iff we're making a type pack expansion. */
3799 };
3801 /* Identifies all of the argument packs that occur in a template
3802 argument and appends them to the TREE_LIST inside DATA, which is a
3803 find_parameter_pack_data structure. This is a subroutine of
3804 make_pack_expansion and uses_parameter_packs. */
3805 static tree
3807 {
3813 /* Handle type aliases/typedefs. */
3815 {
3822 }
3824 /* Identify whether this is a parameter pack or not. */
3826 {
3834 /* FALLTHRU */
3836 /* If the placeholder appears in the decl-specifier-seq of a function
3837 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3838 is a pack expansion, the invented template parameter is a template
3839 parameter pack. */
3849 {
3850 /* We don't want to walk into the type of a PARM_DECL,
3851 because we don't want to see the type parameter pack. */
3854 }
3859 {
3860 /* We don't want to walk into the type of a variadic capture proxy,
3861 because we don't want to see the type parameter pack. */
3864 }
3866 {
3868 find_parameter_packs_r,
3871 }
3883 /* Not a parameter pack. */
3885 }
3888 {
3889 /* Add this parameter pack to the list. */
3891 }
3897 /* This switch statement will return immediately if we don't find a
3898 parameter pack. */
3900 {
3905 /* Check the template itself. */
3908 /* Check the template arguments. */
3922 /* Ignore the declaration of a capture proxy for a parameter pack. */
3930 /* Fall through. */
3975 {
3976 /* Look at explicit captures. */
3981 /* Since we defer implicit capture, look in the parms and body. */
3989 }
3992 {
3993 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3994 type_pack_expansion_p to false so that any placeholders
3995 within the expression don't get marked as parameter packs. */
4003 }
4012 /* Don't walk into IF_STMT_EXTRA_ARGS. */
4018 }
4021 }
4023 /* Determines if the expression or type T uses any parameter packs. */
4024 tree
4026 {
4035 }
4037 /* Turn ARG, which may be an expression, type, or a TREE_LIST
4038 representation a base-class initializer into a parameter pack
4039 expansion. If all goes well, the resulting node will be an
4040 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
4041 respectively. */
4042 tree
4044 {
4045 tree result;
4054 {
4055 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
4056 class initializer. In this case, the TREE_PURPOSE will be a
4057 _TYPE node (representing the base class expansion we're
4058 initializing) and the TREE_VALUE will be a TREE_LIST
4059 containing the initialization arguments.
4061 The resulting expansion looks somewhat different from most
4062 expansions. Rather than returning just one _EXPANSION, we
4063 return a TREE_LIST whose TREE_PURPOSE is a
4064 TYPE_PACK_EXPANSION containing the bases that will be
4065 initialized. The TREE_VALUE will be identical to the
4066 original TREE_VALUE, which is a list of arguments that will
4067 be passed to each base. We do not introduce any new pack
4068 expansion nodes into the TREE_VALUE (although it is possible
4069 that some already exist), because the TREE_PURPOSE and
4070 TREE_VALUE all need to be expanded together with the same
4071 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
4072 resulting TREE_PURPOSE will mention the parameter packs in
4073 both the bases and the arguments to the bases. */
4074 tree purpose;
4075 tree value;
4078 /* Determine which parameter packs will be used by the base
4079 class expansion. */
4088 {
4091 arg);
4094 }
4097 {
4098 /* Collect the sets of parameter packs used in each of the
4099 initialization arguments. */
4101 {
4102 /* Determine which parameter packs will be expanded in this
4103 argument. */
4106 }
4107 }
4111 /* Create the pack expansion type for the base type. */
4117 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4118 they will rarely be compared to anything. */
4122 }
4127 /* Build the PACK_EXPANSION_* node. */
4128 result = for_types
4133 {
4134 /* Propagate type and const-expression information. */
4137 /* Mark this read now, since the expansion might be length 0. */
4139 }
4140 else
4141 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4142 they will rarely be compared to anything. */
4145 /* Determine which parameter packs will be expanded. */
4152 /* Make sure we found some parameter packs. */
4154 {
4156 {
4159 else
4161 }
4163 }
4169 }
4171 /* Checks T for any "bare" parameter packs, which have not yet been
4172 expanded, and issues an error if any are found. This operation can
4173 only be done on full expressions or types (e.g., an expression
4174 statement, "if" condition, etc.), because we could have expressions like:
4176 foo(f(g(h(args)))...)
4178 where "args" is a parameter pack. check_for_bare_parameter_packs
4179 should not be called for the subexpressions args, h(args),
4180 g(h(args)), or f(g(h(args))), because we would produce erroneous
4181 error messages.
4183 Returns TRUE and emits an error if there were bare parameter packs,
4184 returns FALSE otherwise. */
4185 bool
4187 {
4194 /* A lambda might use a parameter pack from the containing context. */
4209 {
4214 {
4225 else
4230 else
4234 }
4237 }
4240 }
4242 /* Expand any parameter packs that occur in the template arguments in
4243 ARGS. */
4244 tree
4246 {
4255 /* First, determine if we need to expand anything, and the number of
4256 slots we'll need. */
4258 {
4263 {
4267 else
4269 }
4270 else
4271 {
4273 num_result_args++;
4274 }
4275 }
4277 /* If no expansion is necessary, we're done. */
4281 /* Expand arguments. */
4284 non_default_args_count =
4287 {
4290 {
4297 }
4298 else
4299 {
4302 }
4303 }
4307 }
4309 /* Checks if DECL shadows a template parameter.
4311 [temp.local]: A template-parameter shall not be redeclared within its
4312 scope (including nested scopes).
4314 Emits an error and returns TRUE if the DECL shadows a parameter,
4315 returns FALSE otherwise. */
4317 bool
4319 {
4320 tree olddecl;
4322 /* If we're not in a template, we can't possibly shadow a template
4323 parameter. */
4327 /* Figure out what we're shadowing. */
4331 /* If there's no previous binding for this name, we're not shadowing
4332 anything, let alone a template parameter. */
4336 /* If we're not shadowing a template parameter, we're done. Note
4337 that OLDDECL might be an OVERLOAD (or perhaps even an
4338 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4339 node. */
4343 /* We check for decl != olddecl to avoid bogus errors for using a
4344 name inside a class. We check TPFI to avoid duplicate errors for
4345 inline member templates. */
4351 /* Don't complain about the injected class name, as we've already
4352 complained about the class itself. */
4359 else
4364 }
4366 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4367 ORIG_LEVEL, DECL, and TYPE. */
4369 static tree
4373 tree decl,
4374 tree type)
4375 {
4386 }
4388 /* Find the canonical type parameter for the given template type
4389 parameter. Returns the canonical type parameter, which may be TYPE
4390 if no such parameter existed. */
4392 static tree
4394 {
4395 tree list;
4409 else
4410 {
4414 }
4415 }
4417 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4418 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4419 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4420 new one is created. */
4422 static tree
4424 tsubst_flags_t complain)
4425 {
4430 {
4449 /* Template template parameters need this. */
4451 {
4458 }
4459 }
4462 }
4464 /* Process information from new template parameter PARM and append it
4465 to the LIST being built. This new parameter is a non-type
4466 parameter iff IS_NON_TYPE is true. This new parameter is a
4467 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4468 is in PARM_LOC. */
4470 tree
4473 {
4482 {
4486 {
4490 else
4492 }
4495 }
4498 {
4504 {
4505 /* [temp.param]
4507 The top-level cv-qualifiers on the template-parameter are
4508 ignored when determining its type. */
4513 && !is_parameter_pack
4514 /* If we're in a nested template parameter list, the template
4515 template parameter could be a parameter pack. */
4517 {
4518 /* This template parameter is not a parameter pack, but it
4519 should be. Complain about "bare" parameter packs. */
4522 /* Recover by calling this a parameter pack. */
4524 }
4525 }
4527 /* A template parameter is not modifiable. */
4536 processing_template_decl,
4541 }
4542 else
4543 {
4544 tree t;
4548 {
4550 /* This is for distinguishing between real templates and template
4551 template parameters */
4555 }
4556 else
4557 {
4559 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4562 }
4569 processing_template_decl,
4573 }
4577 /* Build requirements for the type/template parameter.
4578 This must be done after SET_DECL_TEMPLATE_PARM_P or
4579 process_template_parm could fail. */
4586 /* Build the parameter node linking the parameter declaration,
4587 its default argument (if any), and its constraints (if any). */
4592 }
4594 /* The end of a template parameter list has been reached. Process the
4595 tree list into a parameter vector, converting each parameter into a more
4596 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4597 as PARM_DECLs. */
4599 tree
4601 {
4606 /* Pop the dummy parameter level and add the real one. */
4609 current_template_parms
4614 {
4618 }
4623 }
4625 // Explicitly indicate the end of the template parameter list. We assume
4626 // that the current template parameters have been constructed and/or
4627 // managed explicitly, as when creating new template template parameters
4628 // from a shorthand constraint.
4629 void
4631 {
4633 }
4635 /* end_template_decl is called after a template declaration is seen. */
4637 void
4639 {
4645 /* This matches the pushlevel in begin_template_parm_list. */
4650 }
4652 /* Takes a TREE_LIST representing a template parameter and convert it
4653 into an argument suitable to be passed to the type substitution
4654 functions. Note that If the TREE_LIST contains an error_mark
4655 node, the returned argument is error_mark_node. */
4657 tree
4659 {
4672 {
4676 {
4677 /* Turn this argument into a TYPE_ARGUMENT_PACK
4678 with a single element, which expands T. */
4687 }
4688 }
4689 else
4690 {
4694 {
4695 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4696 with a single element, which expands T. */
4706 }
4707 else
4709 }
4711 }
4713 /* Given a single level of template parameters (a TREE_VEC), return it
4714 as a set of template arguments. */
4716 tree
4718 {
4728 }
4730 /* Given a set of template parameters, return them as a set of template
4731 arguments. The template parameters are represented as a TREE_VEC, in
4732 the form documented in cp-tree.h for template arguments. */
4734 tree
4736 {
4737 tree header;
4742 /* If there is only one level of template parameters, we do not
4743 create a TREE_VEC of TREE_VECs. Instead, we return a single
4744 TREE_VEC containing the arguments. */
4749 {
4754 else
4756 }
4759 }
4761 /* Within the declaration of a template, return the currently active
4762 template parameters as an argument TREE_VEC. */
4764 static tree
4766 {
4768 }
4770 /* Return the fully generic arguments for of TMPL, i.e. what
4771 current_template_args would be while parsing it. */
4773 tree
4775 {
4780 /* DECL_TEMPLATE_RESULT doesn't have the arguments we want. For a template
4781 template parameter, it has no TEMPLATE_INFO; for a partial
4782 specialization, it has the arguments for the primary template, and we
4788 }
4790 /* Update the declared TYPE by doing any lookups which were thought to be
4791 dependent, but are not now that we know the SCOPE of the declarator. */
4793 tree
4795 {
4806 /* Don't bother building up the args in this case. */
4808 {
4809 /* tsubst in the args corresponding to the template parameters,
4810 including auto if present. Most things will be unchanged, but
4811 make_typename_type and tsubst_qualified_id will resolve
4812 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4815 tree pushed;
4817 {
4821 }
4826 }
4832 {
4835 else
4837 }
4839 }
4841 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4842 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4843 the new template is a member template. */
4845 static tree
4847 {
4856 }
4858 struct template_parm_data
4859 {
4860 /* The level of the template parameters we are currently
4861 processing. */
4864 /* The index of the specialization argument we are currently
4865 processing. */
4868 /* An array whose size is the number of template parameters. The
4869 elements are nonzero if the parameter has been used in any one
4870 of the arguments processed so far. */
4873 /* An array whose size is the number of template arguments. The
4874 elements are nonzero if the argument makes use of template
4875 parameters of this level. */
4877 };
4879 /* Subroutine of push_template_decl used to see if each template
4880 parameter in a partial specialization is used in the explicit
4881 argument list. If T is of the LEVEL given in DATA (which is
4882 treated as a template_parm_data*), then DATA->PARMS is marked
4883 appropriately. */
4885 static int
4887 {
4895 {
4898 }
4900 /* In C++17 the type of a non-type argument is a deduced context. */
4905 data,
4906 NULL,
4909 /* Return zero so that for_each_template_parm will continue the
4910 traversal of the tree; we want to mark *every* template parm. */
4912 }
4914 /* Process the partial specialization DECL. */
4916 static tree
4918 {
4925 tree inner_parms;
4926 tree inst;
4936 /* A concept cannot be specialized. */
4938 {
4941 }
4946 /* We check that each of the template parameters given in the
4947 partial specialization is used in the argument list to the
4948 specialization. For example:
4950 template <class T> struct S;
4951 template <class T> struct S<T*>;
4953 The second declaration is OK because `T*' uses the template
4954 parameter T, whereas
4956 template <class T> struct S<int>;
4958 is no good. Even trickier is:
4960 template <class T>
4961 struct S1
4962 {
4963 template <class U>
4964 struct S2;
4965 template <class U>
4966 struct S2<T>;
4967 };
4969 The S2<T> declaration is actually invalid; it is a
4970 full-specialization. Of course,
4972 template <class U>
4973 struct S2<T (*)(U)>;
4975 or some such would have been OK. */
4983 {
4988 NULL,
4990 }
4993 {
4994 /* One of the template parms was not used in a deduced context in the
4995 specialization. */
4997 {
5001 }
5005 }
5010 /* [temp.class.spec]
5012 The argument list of the specialization shall not be identical to
5013 the implicit argument list of the primary template. */
5014 tree main_args
5017 && (!flag_concepts
5020 {
5023 "any template arguments; to define the primary template, "
5025 else
5027 "template arguments and is not more constrained than "
5028 "the primary template; to define the primary template, "
5031 }
5033 /* A partial specialization that replaces multiple parameters of the
5034 primary template with a pack expansion is less specialized for those
5035 parameters. */
5037 {
5039 "primary template because it replaces multiple parameters "
5042 /* Avoid crash in process_partial_specialization. */
5044 }
5046 /* If we aren't in a dependent class, we can actually try deduction. */
5048 /* FIXME we should be able to handle a partial specialization of a
5049 partial instantiation, but currently we can't (c++/41727). */
5052 {
5053 auto_diagnostic_group d;
5057 maintmpl);
5058 }
5060 /* [temp.class.spec]
5062 A partially specialized non-type argument expression shall not
5063 involve template parameters of the partial specialization except
5064 when the argument expression is a simple identifier.
5066 The type of a template parameter corresponding to a specialized
5067 non-type argument shall not be dependent on a parameter of the
5068 specialization.
5070 Also, we verify that pack expansions only occur at the
5071 end of the argument list. */
5075 {
5082 {
5083 /* Extract the arguments from the argument pack. We'll be
5084 iterating over these in the following loop. */
5087 }
5090 {
5092 /* Get the Jth argument in the parameter pack. */
5096 {
5097 /* Pack expansions must come at the end of the
5098 argument list. */
5101 {
5105 else
5108 }
5109 }
5112 /* We only care about the pattern. */
5118 /* This next two lines are the `argument expression is not just a
5119 simple identifier' condition and also the `specialized
5120 non-type argument' bit. */
5125 {
5129 "template argument %qE involves template "
5131 else
5132 {
5133 /* Look at the corresponding template parameter,
5134 marking which template parameters its type depends
5135 upon. */
5139 {
5140 /* We haven't yet initialized TPD2. Do so now. */
5142 /* The number of parameters here is the number in the
5143 main template, which, as checked in the assertion
5144 above, is NARGS. */
5148 }
5150 /* Mark the template parameters. But this time, we're
5151 looking for the template parameters of the main
5152 template, not in the specialization. */
5159 NULL,
5163 {
5164 /* The type depended on some template parameters.
5165 If they are fully specialized in the
5166 specialization, that's OK. */
5175 "type %qT of template argument %qE depends "
5177 "type %qT of template argument %qE depends "
5179 type,
5180 arg);
5181 }
5182 }
5183 }
5184 }
5185 }
5187 /* We should only get here once. */
5191 // Build the template decl.
5200 /* Give template template parms a DECL_CONTEXT of the template
5201 for which they are a parameter. */
5203 {
5207 }
5210 /* We didn't register this in check_explicit_specialization so we could
5211 wait until the constraints were set. */
5213 else
5223 {
5229 {
5237 "declaration of %qD ambiguates earlier template "
5241 "partial specialization of %qD after instantiation "
5243 }
5244 }
5247 }
5249 /* PARM is a template parameter of some form; return the corresponding
5250 TEMPLATE_PARM_INDEX. */
5252 static tree
5254 {
5267 }
5269 /* Subroutine of fixed_parameter_pack_p below. Look for any template
5270 parameter packs used by the template parameter PARM. */
5272 static void
5274 {
5275 /* A type parm can't refer to another parm. */
5279 {
5283 }
5289 {
5293 else
5295 }
5296 }
5298 /* PARM is a template parameter pack. Return any parameter packs used in
5299 its type or the type of any of its template parameters. If there are
5300 any such packs, it will be instantiated into a fixed template parameter
5301 list by partial instantiation rather than be fully deduced. */
5303 tree
5305 {
5306 /* This can only be true in a member template. */
5309 /* This can only be true for a parameter pack. */
5312 /* A type parm can't refer to another parm. */
5326 }
5328 /* Check that a template declaration's use of default arguments and
5329 parameter packs is not invalid. Here, PARMS are the template
5330 parameters. IS_PRIMARY is true if DECL is the thing declared by
5331 a primary template. IS_PARTIAL is true if DECL is a partial
5332 specialization.
5334 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
5335 function template declaration or a friend class template
5336 declaration. In the function case, 1 indicates a declaration, 2
5337 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
5338 emitted for extraneous default arguments.
5340 Returns TRUE if there were no errors found, FALSE otherwise. */
5342 bool
5345 {
5348 tree parm_level;
5351 /* [temp.param]
5353 A default template-argument shall not be specified in a
5354 function template declaration or a function template definition, nor
5355 in the template-parameter-list of the definition of a member of a
5356 class template. */
5360 /* You can't have a function template declaration in a local
5361 scope, nor you can you define a member of a class template in a
5362 local scope. */
5370 /* A lambda doesn't have an explicit declaration; don't complain
5371 about the parms of the enclosing class. */
5378 /* If this is either a friend defined in the scope of the class
5379 or a member function. */
5385 /* And, if it was a member function, it really was defined in
5386 the scope of the class. */
5389 /* We already checked these parameters when the template was
5390 declared, so there's no need to do it again now. This function
5391 was defined in class scope, but we're processing its body now
5392 that the class is complete. */
5395 /* Core issue 226 (C++0x only): the following only applies to class
5396 templates. */
5399 {
5400 /* [temp.param]
5402 If a template-parameter has a default template-argument, all
5403 subsequent template-parameters shall have a default
5404 template-argument supplied. */
5406 {
5413 {
5423 {
5425 /* For better subsequent error-recovery, we indicate that
5426 there should have been a default argument. */
5429 }
5431 && !is_friend_decl
5432 /* Don't complain about an enclosing partial
5433 specialization. */
5438 /* A fixed parameter pack will be partially
5439 instantiated into a fixed length list. */
5441 {
5442 /* A primary class template can only have one
5443 parameter pack, at the end of the template
5444 parameter list. */
5452 }
5453 }
5454 }
5455 }
5458 || is_partial
5459 || !is_primary
5461 /* For an ordinary class template, default template arguments are
5462 allowed at the innermost level, e.g.:
5463 template <class T = int>
5464 struct S {};
5465 but, in a partial specialization, they're not allowed even
5466 there, as we have in [temp.class.spec]:
5468 The template parameter list of a specialization shall not
5469 contain default template argument values.
5471 So, for a partial specialization, or for a function template
5472 (in C++98/C++03), we look at all of them. */
5473 ;
5474 else
5475 /* But, for a primary class template that is not a partial
5476 specialization we look at all template parameters except the
5477 innermost ones. */
5480 /* Figure out what error message to issue. */
5495 else
5496 /* Per [temp.param]/9, "A default template-argument shall not be
5497 specified in the template-parameter-lists of the definition of
5498 a member of a class template that appears outside of the member's
5499 class.", thus if we aren't handling a member of a class template
5500 there is no need to examine the parameters. */
5504 /* If we're inside a class definition, there's no need to
5505 examine the parameters to the class itself. On the one
5506 hand, they will be checked when the class is defined, and,
5507 on the other, default arguments are valid in things like:
5508 template <class T = double>
5509 struct S { template <class U> void f(U); };
5510 Here the default argument for `S' has no bearing on the
5511 declaration of `f'. */
5513 else
5514 /* Check everything. */
5520 {
5527 {
5532 {
5534 {
5541 }
5543 /* Clear out the default argument so that we are not
5544 confused later. */
5546 }
5547 }
5549 /* At this point, if we're still interested in issuing messages,
5550 they must apply to classes surrounding the object declared. */
5554 }
5557 }
5559 /* Worker for push_template_decl_real, called via
5560 for_each_template_parm. DATA is really an int, indicating the
5561 level of the parameters we are interested in. If T is a template
5562 parameter of that level, return nonzero. */
5564 static int
5566 {
5572 else
5575 }
5577 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5578 DATA is really an int, indicating the innermost outer level of parameters.
5579 If T is a template parameter of that level or further out, return
5580 nonzero. */
5582 static int
5584 {
5590 else
5593 }
5595 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5596 parameters given by current_template_args, or reuses a
5597 previously existing one, if appropriate. Returns the DECL, or an
5598 equivalent one, if it is replaced via a call to duplicate_decls.
5600 If IS_FRIEND is true, DECL is a friend declaration. */
5602 tree
5604 {
5605 tree tmpl;
5606 tree args;
5607 tree info;
5608 tree ctx;
5612 /* True if the template is a member template, in the sense of
5613 [temp.mem]. */
5619 /* See if this is a partial specialization. */
5632 /* For a friend, we want the context of the friend, not
5633 the type of which it is a friend. */
5637 /* In the case of a virtual function, we want the class in which
5638 it is defined. */
5640 else
5641 /* Otherwise, if we're currently defining some class, the DECL
5642 is assumed to be a member of the class. */
5651 /* See if this is a primary template. */
5654 /* A friend template that specifies a class context, i.e.
5655 template <typename T> friend void A<T>::f();
5656 is not primary. */
5661 else
5665 {
5672 {
5675 }
5677 {
5679 {
5682 }
5684 {
5685 /* [temp.mem]
5687 A destructor shall not be a member template. */
5691 }
5698 {
5699 /* [basic.stc.dynamic.allocation]
5701 An allocation function can be a function
5702 template. ... Template allocation functions shall
5703 have two or more parameters. */
5706 }
5707 }
5710 {
5711 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5714 {
5720 }
5721 }
5724 /* alias-declaration */
5730 else
5731 {
5734 }
5735 }
5737 /* Check to see that the rules regarding the use of default
5738 arguments are not being violated. We check args for a friend
5739 functions when we know whether it's a definition, introducing
5740 declaration or re-declaration. */
5745 /* Ensure that there are no parameter packs in the type of this
5746 declaration that have not been expanded. */
5748 {
5749 /* Check each of the arguments individually to see if there are
5750 any bare parameter packs. */
5756 {
5759 {
5760 /* This is a PARM_DECL that contains unexpanded parameter
5761 packs. We have already complained about this in the
5762 check_for_bare_parameter_packs call, so just replace
5763 these types with ERROR_MARK_NODE. */
5766 }
5770 }
5772 /* Check for bare parameter packs in the return type and the
5773 exception specifiers. */
5775 /* Errors were already issued, set return type to int
5776 as the frontend doesn't expect error_mark_node as
5777 the return type. */
5781 }
5786 {
5789 }
5802 {
5807 /* If DECL is a TYPE_DECL for a class-template, then there won't
5808 be DECL_LANG_SPECIFIC. The information equivalent to
5809 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5813 {
5814 /* Since a template declaration already existed for this
5815 class-type, we must be redeclaring it here. Make sure
5816 that the redeclaration is valid. */
5818 current_template_parms,
5820 /* We don't need to create a new TEMPLATE_DECL; just use the
5821 one we already had. */
5823 }
5824 else
5825 {
5827 member_template_p);
5832 {
5833 /* A specialization of a member template of a template
5834 class. */
5838 }
5839 }
5840 }
5841 else
5842 {
5848 {
5851 }
5859 {
5860 tree new_tmpl;
5862 /* The declaration is a specialization of a member
5863 template, declared outside the class. Therefore, the
5864 innermost template arguments will be NULL, so we
5865 replace them with the arguments determined by the
5866 earlier call to check_explicit_specialization. */
5869 new_tmpl
5871 member_template_p);
5881 args,
5884 }
5886 /* Make sure the template headers we got make sense. */
5891 {
5896 }
5897 else
5899 {
5904 {
5908 else
5912 /* Avoid crash in import_export_decl. */
5915 }
5920 /* Can happen in erroneous input. */
5922 else
5924 }
5926 /* Check that the parms are used in the appropriate qualifying scopes
5927 in the declarator. */
5931 {
5937 /* Avoid crash in import_export_decl. */
5940 }
5941 }
5946 /* Push template declarations for global functions and types. Note
5947 that we do not try to push a global template friend declared in a
5948 template class; such a thing may well depend on the template
5949 parameters of the class. */
5952 {
5957 /* Hide template friend classes that haven't been declared yet. */
5959 {
5962 }
5963 }
5966 {
5971 /* Give template template parms a DECL_CONTEXT of the template
5972 for which they are a parameter. */
5975 {
5979 }
5985 }
5987 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5988 back to its most general template. If TMPL is a specialization,
5989 ARGS may only have the innermost set of arguments. Add the missing
5990 argument levels if necessary. */
5998 else
5999 {
6004 }
6007 && !is_friend
6010 /* Set DECL_COMDAT on template instantiations; if we force
6011 them to be emitted by explicit instantiation,
6012 mark_needed will tell cgraph to do the right thing. */
6016 }
6018 tree
6020 {
6022 }
6024 /* FN is an inheriting constructor that inherits from the constructor
6025 template INHERITED; turn FN into a constructor template with a matching
6026 template header. */
6028 tree
6030 {
6031 tree inner_parms
6034 tree parms
6045 }
6047 /* Called when a class template TYPE is redeclared with the indicated
6048 template PARMS, e.g.:
6050 template <class T> struct S;
6051 template <class T> struct S {}; */
6053 bool
6055 {
6056 tree tmpl;
6057 tree tmpl_parms;
6061 {
6064 }
6068 /* The type is nested in some template class. Nothing to worry
6069 about here; there are no new template parameters for the nested
6070 type. */
6074 {
6076 tmpl);
6078 }
6084 {
6094 }
6097 {
6098 tree tmpl_parm;
6099 tree parm;
6100 tree tmpl_default;
6101 tree parm_default;
6115 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
6116 TEMPLATE_DECL. */
6126 {
6130 }
6132 /* The parameters can be declared to introduce different
6133 constraints. */
6137 {
6143 }
6146 {
6147 /* We have in [temp.param]:
6149 A template-parameter may not be given default arguments
6150 by two different declarations in the same scope. */
6155 }
6158 /* Update the previous template parameters (which are the ones
6159 that will really count) with the new default value. */
6162 /* Update the new parameters, too; they'll be used as the
6163 parameters for any members. */
6166 /* Give each template template parm in this redeclaration a
6167 DECL_CONTEXT of the template for which they are a parameter. */
6169 {
6172 }
6176 }
6182 /* Two classes with different constraints declare different entities. */
6184 {
6190 }
6193 }
6195 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
6196 to be used when the caller has already checked
6197 (processing_template_decl
6198 && !instantiation_dependent_expression_p (expr)
6199 && potential_constant_expression (expr))
6200 and cleared processing_template_decl. */
6202 tree
6204 {
6207 complain,
6211 }
6213 /* Simplify EXPR if it is a non-dependent expression. Returns the
6214 (possibly simplified) expression. */
6216 tree
6218 {
6222 /* If we're in a template, but EXPR isn't value dependent, simplify
6223 it. We're supposed to treat:
6225 template <typename T> void f(T[1 + 1]);
6226 template <typename T> void f(T[2]);
6228 as two declarations of the same function, for example. */
6231 {
6232 processing_template_decl_sentinel s;
6234 }
6236 }
6238 tree
6240 {
6242 }
6244 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
6245 an uninstantiated expression. */
6247 tree
6249 {
6253 {
6256 else
6257 {
6258 processing_template_decl_sentinel s;
6260 }
6261 }
6263 }
6265 /* True iff T is a specialization of a variable template. */
6267 bool
6269 {
6274 }
6276 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
6277 template declaration, or a TYPE_DECL for an alias declaration. */
6279 bool
6281 {
6289 }
6291 /* Return TRUE iff T is a specialization of an alias template. */
6293 bool
6295 {
6296 /* It's an alias template specialization if it's an alias and its
6297 TYPE_NAME is a specialization of a primary template. */
6303 }
6305 /* An alias template is complex from a SFINAE perspective if a template-id
6306 using that alias can be ill-formed when the expansion is not, as with
6307 the void_t template. We determine this by checking whether the
6308 expansion for the alias template uses all its template parameters. */
6310 struct uses_all_template_parms_data
6311 {
6314 };
6316 static int
6318 {
6326 }
6328 static bool
6330 {
6345 }
6347 /* Return TRUE iff T is a specialization of a complex alias template with
6348 dependent template-arguments. */
6350 bool
6352 {
6365 }
6367 /* Return the number of innermost template parameters in TMPL. */
6369 static int
6371 {
6374 }
6376 /* Return either TMPL or another template that it is equivalent to under DR
6377 1286: An alias that just changes the name of a template is equivalent to
6378 the other template. */
6380 static tree
6382 {
6385 {
6386 /* Determine if the alias is equivalent to an underlying template. */
6402 /* Alias is equivalent. Strip it and repeat. */
6404 }
6407 }
6409 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6410 must be a reference-to-function or a pointer-to-function type, as specified
6411 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6412 and check that the resulting function has external linkage. */
6414 static tree
6416 tsubst_flags_t complain)
6417 {
6420 linkage_kind linkage;
6435 /* [temp.arg.nontype]/1
6437 A template-argument for a non-type, non-template template-parameter
6438 shall be one of:
6439 [...]
6440 -- the address of an object or function with external [C++11: or
6441 internal] linkage. */
6445 {
6447 {
6454 else
6457 }
6459 }
6463 {
6465 {
6471 else
6475 }
6477 }
6479 accept:
6481 {
6484 else
6486 }
6491 }
6493 /* Subroutine of convert_nontype_argument.
6494 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6495 Emit an error otherwise. */
6497 static bool
6499 tsubst_flags_t complain)
6500 {
6516 {
6522 else
6524 }
6526 }
6528 /* Returns TRUE iff the address of OP is value-dependent.
6530 14.6.2.4 [temp.dep.temp]:
6531 A non-integral non-type template-argument is dependent if its type is
6532 dependent or it has either of the following forms
6533 qualified-id
6534 & qualified-id
6535 and contains a nested-name-specifier which specifies a class-name that
6536 names a dependent type.
6538 We generalize this to just say that the address of a member of a
6539 dependent class is value-dependent; the above doesn't cover the
6540 address of a static data member named with an unqualified-id. */
6542 static bool
6544 {
6545 /* We could use get_inner_reference here, but there's no need;
6546 this is only relevant for template non-type arguments, which
6547 can only be expressed as &id-expression. */
6549 {
6553 }
6556 }
6558 /* The next set of functions are used for providing helpful explanatory
6559 diagnostics for failed overload resolution. Their messages should be
6560 indented by two spaces for consistency with the messages in
6561 call.c */
6563 static int
6565 {
6567 }
6569 /* Other failure functions should call this one, to provide a single function
6570 for setting a breakpoint on. */
6572 static int
6574 {
6576 }
6578 static int
6580 {
6585 }
6587 static int
6589 {
6595 }
6597 static int
6599 {
6603 }
6605 static int
6607 {
6610 " template parameter %qD is not a parameter pack, but "
6614 }
6616 static int
6618 {
6621 " template argument %qE does not match "
6625 }
6627 static int
6629 {
6633 }
6635 static int
6637 {
6643 }
6645 static int
6647 {
6649 {
6654 else
6656 " deduced conflicting values for non-type parameter "
6658 }
6660 }
6662 static int
6664 {
6667 " variable-sized array type %qT is not "
6669 arg);
6671 }
6673 static int
6675 {
6679 arg);
6681 }
6683 static int
6685 {
6687 {
6693 else
6698 }
6700 }
6702 static int
6704 {
6706 }
6708 static int
6711 {
6713 }
6715 static int
6718 {
6724 }
6726 static int
6729 {
6732 {
6740 }
6742 }
6744 static int
6746 {
6749 " template parameters of a template template argument are "
6752 }
6754 static int
6756 {
6762 }
6764 static int
6766 {
6771 }
6773 /* True if T is a C++20 template parameter object to store the argument for a
6774 template parameter of class type. */
6776 bool
6778 {
6781 }
6783 /* Subroutine of convert_nontype_argument, to check whether EXPR, as an
6784 argument for TYPE, points to an unsuitable object. */
6786 static bool
6788 {
6790 {
6791 CASE_CONVERT:
6793 complain);
6797 complain);
6800 {
6805 }
6809 {
6813 {
6816 "%qE is not a valid template argument of type %qT "
6819 }
6821 {
6824 "%qE is not a valid template argument of type %qT "
6828 }
6831 {
6834 "%qE is not a valid template argument of type %qT "
6837 }
6838 /* C++17: For a non-type template-parameter of reference or pointer
6839 type, the value of the constant expression shall not refer to (or
6840 for a pointer type, shall not be the address of):
6841 * a subobject (4.5),
6842 * a temporary object (15.2),
6843 * a string literal (5.13.5),
6844 * the result of a typeid expression (8.2.8), or
6845 * a predefined __func__ variable (11.4.1). */
6847 {
6850 decl);
6852 }
6856 {
6861 }
6863 {
6867 decl);
6869 }
6870 }
6878 else
6879 {
6881 {
6884 "because %qD is a variable, not the address of "
6887 }
6888 else
6889 {
6895 }
6896 }
6897 }
6900 }
6902 /* Return a VAR_DECL for the C++20 template parameter object corresponding to
6903 template argument EXPR. */
6905 static tree
6907 {
6912 {
6917 }
6937 }
6939 /* Attempt to convert the non-type template parameter EXPR to the
6940 indicated TYPE. If the conversion is successful, return the
6941 converted value. If the conversion is unsuccessful, return
6942 NULL_TREE if we issued an error message, or error_mark_node if we
6943 did not. We issue error messages for out-and-out bad template
6944 parameters, but not simply because the conversion failed, since we
6945 might be just trying to do argument deduction. Both TYPE and EXPR
6946 must be non-dependent.
6948 The conversion follows the special rules described in
6949 [temp.arg.nontype], and it is much more strict than an implicit
6950 conversion.
6952 This function is called twice for each template argument (see
6953 lookup_template_class for a more accurate description of this
6954 problem). This means that we need to handle expressions which
6955 are not valid in a C++ source, but can be created from the
6956 first call (for instance, casts to perform conversions). These
6957 hacks can go away after we fix the double coercion problem. */
6959 static tree
6961 {
6962 tree expr_type;
6965 /* Detect immediately string literals as invalid non-type argument.
6966 This special-case is not needed for correctness (we would easily
6967 catch this later), but only to provide better diagnostic for this
6968 common user mistake. As suggested by DR 100, we do not mention
6969 linkage issues in the diagnostic as this is not the point. */
6971 {
6977 }
6979 /* Add the ADDR_EXPR now for the benefit of
6980 value_dependent_expression_p. */
6983 {
6987 }
6989 /* If we are in a template, EXPR may be non-dependent, but still
6990 have a syntactic, rather than semantic, form. For example, EXPR
6991 might be a SCOPE_REF, rather than the VAR_DECL to which the
6992 SCOPE_REF refers. Preserving the qualifying scope is necessary
6993 so that access checking can be performed when the template is
6994 instantiated -- but here we need the resolved form so that we can
6995 convert the argument. */
7007 /* If the argument is non-dependent, perform any conversions in
7008 non-dependent context as well. */
7016 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
7017 to a non-type argument of "nullptr". */
7021 /* In C++11, integral or enumeration non-type template arguments can be
7022 arbitrary constant expressions. Pointer and pointer to
7023 member arguments can be general constant expressions that evaluate
7024 to a null value, but otherwise still need to be of a specific form. */
7026 {
7028 /* A PTRMEM_CST is already constant, and a valid template
7029 argument for a parameter of pointer to member type, we just want
7030 to leave it in that form rather than lower it to a
7034 {
7035 /* Calling build_converted_constant_expr might create a call to
7036 a conversion function with a value-dependent argument, which
7037 could invoke taking the address of a temporary representing
7038 the result of the conversion. */
7043 {
7047 }
7048 /* C++17: A template-argument for a non-type template-parameter shall
7049 be a converted constant expression (8.20) of the type of the
7050 template-parameter. */
7053 /* Make sure we return NULL_TREE only if we have really issued
7054 an error, as described above. */
7059 }
7061 {
7067 }
7068 }
7072 else
7075 /* HACK: Due to double coercion, we can get a
7076 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
7077 which is the tree that we built on the first call (see
7078 below when coercing to reference to object or to reference to
7079 function). We just strip everything and get to the arg.
7080 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
7081 for examples. */
7083 {
7089 {
7090 /* ??? Maybe we could use convert_from_reference here, but we
7091 would need to relax its constraints because the NOP_EXPR
7092 could actually change the type to something more cv-qualified,
7093 and this is not folded by convert_from_reference. */
7098 && (same_type_ignoring_top_level_qualifiers_p
7101 {
7104 }
7105 }
7106 }
7108 /* [temp.arg.nontype]/5, bullet 1
7110 For a non-type template-parameter of integral or enumeration type,
7111 integral promotions (_conv.prom_) and integral conversions
7112 (_conv.integral_) are applied. */
7114 {
7116 {
7121 }
7126 /* Notice that there are constant expressions like '4 % 0' which
7127 do not fold into integer constants. */
7130 {
7132 {
7136 else
7142 /* else cxx_constant_value complained but gave us
7143 a real constant, so go ahead. */
7145 {
7146 /* Some assemble time constant expressions like
7147 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
7148 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
7149 as we can emit them into .rodata initializers of
7150 variables, yet they can't fold into an INTEGER_CST at
7151 compile time. Refuse them here. */
7156 }
7157 }
7158 else
7160 }
7162 /* Avoid typedef problems. */
7165 }
7166 /* [temp.arg.nontype]/5, bullet 2
7168 For a non-type template-parameter of type pointer to object,
7169 qualification conversions (_conv.qual_) and the array-to-pointer
7170 conversion (_conv.array_) are applied. */
7172 {
7175 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
7176 decay_conversion or an explicit cast. If it's a problematic cast,
7177 we'll complain about it below. */
7179 {
7184 {
7187 }
7188 }
7190 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
7192 A template-argument for a non-type, non-template template-parameter
7193 shall be one of: [...]
7195 -- the name of a non-type template-parameter;
7196 -- the address of an object or function with external linkage, [...]
7197 expressed as "& id-expression" where the & is optional if the name
7198 refers to a function or array, or if the corresponding
7199 template-parameter is a reference.
7201 Here, we do not care about functions, as they are invalid anyway
7202 for a parameter of type pointer-to-object. */
7205 /* Non-type template parameters are OK. */
7206 ;
7211 /* Other values, like integer constants, might be valid
7212 non-type arguments of some other type. */
7222 }
7223 /* [temp.arg.nontype]/5, bullet 3
7225 For a non-type template-parameter of type reference to object, no
7226 conversions apply. The type referred to by the reference may be more
7227 cv-qualified than the (otherwise identical) type of the
7228 template-argument. The template-parameter is bound directly to the
7229 template-argument, which must be an lvalue. */
7231 {
7233 expr_type))
7237 {
7242 }
7245 {
7250 }
7252 /* [temp.arg.nontype]/1
7254 A template-argument for a non-type, non-template template-parameter
7255 shall be one of: [...]
7257 -- the address of an object or function with external linkage. */
7260 {
7263 {
7266 "because a reference variable does not have a constant "
7269 }
7270 }
7274 /* OK, dependent reference. We don't want to ask whether a DECL is
7276 else
7277 {
7282 }
7286 }
7287 /* [temp.arg.nontype]/5, bullet 4
7289 For a non-type template-parameter of type pointer to function, only
7290 the function-to-pointer conversion (_conv.func_) is applied. If the
7291 template-argument represents a set of overloaded functions (or a
7292 pointer to such), the matching function is selected from the set
7293 (_over.over_). */
7295 {
7296 /* If the argument is a template-id, we might not have enough
7297 context information to decay the pointer. */
7299 {
7303 }
7306 /* Null pointer values are OK in C++11. */
7312 }
7313 /* [temp.arg.nontype]/5, bullet 5
7315 For a non-type template-parameter of type reference to function, no
7316 conversions apply. If the template-argument represents a set of
7317 overloaded functions, the matching function is selected from the set
7318 (_over.over_). */
7320 {
7322 {
7324 {
7329 }
7331 }
7336 }
7337 /* [temp.arg.nontype]/5, bullet 6
7339 For a non-type template-parameter of type pointer to member function,
7340 no conversions apply. If the template-argument represents a set of
7341 overloaded member functions, the matching member function is selected
7342 from the set (_over.over_). */
7344 {
7349 /* [temp.arg.nontype] bullet 1 says the pointer to member
7350 expression must be a pointer-to-member constant. */
7355 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
7356 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
7359 }
7360 /* [temp.arg.nontype]/5, bullet 7
7362 For a non-type template-parameter of type pointer to data member,
7363 qualification conversions (_conv.qual_) are applied. */
7365 {
7366 /* [temp.arg.nontype] bullet 1 says the pointer to member
7367 expression must be a pointer-to-member constant. */
7375 }
7377 {
7379 {
7384 }
7386 }
7388 {
7389 /* Replace the argument with a reference to the corresponding template
7390 parameter object. */
7395 }
7396 /* A template non-type parameter must be one of the above. */
7397 else
7400 /* Sanity check: did we actually convert the argument to the
7401 right type? */
7405 }
7407 /* Subroutine of coerce_template_template_parms, which returns 1 if
7408 PARM_PARM and ARG_PARM match using the rule for the template
7409 parameters of template template parameters. Both PARM and ARG are
7410 template parameters; the rest of the arguments are the same as for
7411 coerce_template_template_parms.
7412 */
7413 static int
7415 tree arg,
7416 tsubst_flags_t complain,
7417 tree in_decl,
7418 tree outer_args)
7419 {
7428 {
7430 /* We encounter instantiations of templates like
7431 template <template <template <class> class> class TT>
7432 class C; */
7433 {
7440 }
7441 /* Fall through. */
7446 /* Argument is a parameter pack but parameter is not. */
7451 /* The tsubst call is used to handle cases such as
7453 template <int> class C {};
7454 template <class T, template <T> class TT> class D {};
7455 D<int, C> d;
7457 i.e. the parameter list of TT depends on earlier parameters. */
7459 {
7464 }
7468 /* Argument is a parameter pack but parameter is not. */
7475 }
7478 }
7480 /* Coerce template argument list ARGLIST for use with template
7481 template-parameter TEMPL. */
7483 static tree
7485 tsubst_flags_t complain)
7486 {
7487 /* Consider an example where a template template parameter declared as
7489 template <class T, class U = std::allocator<T> > class TT
7491 The template parameter level of T and U are one level larger than
7492 of TT. To proper process the default argument of U, say when an
7493 instantiation `TT<int>' is seen, we need to build the full
7494 arguments containing {int} as the innermost level. Outer levels,
7495 available when not appearing as default template argument, can be
7496 obtained from the arguments of the enclosing template.
7498 Suppose that TT is later substituted with std::vector. The above
7499 instantiation is `TT<int, std::allocator<T> >' with TT at
7500 level 1, and T at level 2, while the template arguments at level 1
7501 becomes {std::vector} and the inner level 2 is {int}. */
7507 {
7508 /* This is an argument of the current template, so we haven't set
7509 DECL_CONTEXT yet. */
7510 tree relevant_template_parms;
7512 /* Parameter levels that are greater than the level of the given
7513 template template parm are irrelevant. */
7520 }
7527 complain,
7530 }
7532 /* A cache of template template parameters with match-all default
7533 arguments. */
7536 /* T is a bound template template-parameter. Copy its arguments into default
7537 arguments of the template template-parameter's template parameters. */
7539 static tree
7541 {
7564 {
7567 {
7570 }
7571 }
7575 }
7577 /* ARG is a bound potential template template-argument, and PARGS is a list
7578 of arguments for the corresponding template template-parameter. Adjust
7579 PARGS as appropriate for application to ARG's template, and if ARG is a
7580 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7581 arguments to the template template parameter. */
7583 static tree
7585 {
7589 {
7590 /* When comparing two template template-parameters in partial ordering,
7591 rewrite the one currently being used as an argument to have default
7592 arguments for all parameters. */
7598 }
7599 else
7600 {
7601 tree aparms
7606 }
7609 }
7611 /* Subroutine of unify for the case when PARM is a
7612 BOUND_TEMPLATE_TEMPLATE_PARM. */
7614 static int
7617 {
7621 /* The template template parm might be variadic and the argument
7622 not, so flatten both argument lists. */
7627 {
7628 /* In keeping with P0522R0, adjust P's template arguments
7629 to apply to A's template; then flatten it again. */
7637 /* If the P0522 adjustment eliminated a pack expansion, deduce
7638 empty packs. */
7644 }
7645 else
7646 {
7647 /* Deduce arguments T, i from TT<T> or TT<i>.
7648 We check each element of PARMVEC and ARGVEC individually
7649 rather than the whole TREE_VEC since they can have
7650 different number of elements, which is allowed under N2555. */
7654 /* Check if the parameters end in a pack, making them
7655 variadic. */
7662 /* If the template argument list of P contains a pack
7663 expansion that is not the last template argument, the
7664 entire template argument list is a non-deduced
7665 context. */
7683 DEDUCE_EXACT,
7686 }
7689 }
7691 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7692 template template parameters. Both PARM_PARMS and ARG_PARMS are
7693 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7694 or PARM_DECL.
7696 Consider the example:
7697 template <class T> class A;
7698 template<template <class U> class TT> class B;
7700 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7701 the parameters to A, and OUTER_ARGS contains A. */
7703 static int
7705 tree arg_parms,
7706 tsubst_flags_t complain,
7707 tree in_decl,
7708 tree outer_args)
7709 {
7721 {
7722 /* P0522R0: A template template-parameter P is at least as specialized as
7723 a template template-argument A if, given the following rewrite to two
7724 function templates, the function template corresponding to P is at
7725 least as specialized as the function template corresponding to A
7726 according to the partial ordering rules for function templates
7727 ([temp.func.order]). Given an invented class template X with the
7728 template parameter list of A (including default arguments):
7730 * Each of the two function templates has the same template parameters,
7731 respectively, as P or A.
7733 * Each function template has a single function parameter whose type is
7734 a specialization of X with template arguments corresponding to the
7735 template parameters from the respective function template where, for
7736 each template parameter PP in the template parameter list of the
7737 function template, a corresponding template argument AA is formed. If
7738 PP declares a parameter pack, then AA is the pack expansion
7739 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7741 If the rewrite produces an invalid type, then P is not at least as
7742 specialized as A. */
7744 /* So coerce P's args to apply to A's parms, and then deduce between A's
7745 args and the converted args. If that succeeds, A is at least as
7746 specialized as P, so they match.*/
7754 {
7760 }
7761 }
7763 /* Determine whether we have a parameter pack at the end of the
7764 template template parameter's template parameter list. */
7766 {
7773 {
7787 }
7788 }
7794 /* Check all of the template parameters except the parameter pack at
7795 the end (if any). */
7797 {
7806 outer_args))
7809 }
7812 {
7813 /* Check each of the template parameters in the template
7814 argument against the template parameter pack at the end of
7815 the template template parameter. */
7822 {
7829 outer_args))
7831 }
7832 }
7835 }
7837 /* Verifies that the deduced template arguments (in TARGS) for the
7838 template template parameters (in TPARMS) represent valid bindings,
7839 by comparing the template parameter list of each template argument
7840 to the template parameter list of its corresponding template
7841 template parameter, in accordance with DR150. This
7842 routine can only be called after all template arguments have been
7843 deduced. It will return TRUE if all of the template template
7844 parameter bindings are okay, FALSE otherwise. */
7845 bool
7847 {
7851 /* We're dealing with template parms in this process. */
7857 {
7862 {
7867 {
7868 /* Look inside the argument pack. */
7871 }
7874 {
7878 /* Extract the next argument from the argument
7879 pack. */
7883 /* Look at the pattern of the pack expansion. */
7886 /* Extract the template parameters from the template
7887 argument. */
7893 /* Verify that we can coerce the template template
7894 parameters from the template argument to the template
7895 parameter. This requires an exact match. */
7897 && !coerce_template_template_parms
7899 targ_parms,
7900 tf_none,
7901 tparm,
7902 targs))
7903 {
7906 }
7907 }
7908 }
7909 }
7911 out:
7915 }
7917 /* Since type attributes aren't mangled, we need to strip them from
7918 template type arguments. */
7920 static tree
7922 {
7932 }
7934 /* And from inside dependent non-type arguments like sizeof(Type). */
7936 static tree
7938 {
7948 }
7950 // A template declaration can be substituted for a constrained
7951 // template template parameter only when the argument is more
7952 // constrained than the parameter.
7953 static bool
7955 {
7958 /* For now, allow constrained template template arguments
7959 and unconstrained template template parameters. */
7963 /* If the template parameter is constrained, we need to rewrite its
7964 constraints in terms of the ARG's template parameters. This ensures
7965 that all of the template parameter types will have the same depth.
7967 Note that this is only valid when coerce_template_template_parm is
7968 true for the innermost template parameters of PARM and ARG. In other
7969 words, because coercion is successful, this conversion will be valid. */
7972 {
7979 }
7982 }
7984 // Convert a placeholder argument into a binding to the original
7985 // parameter. The original parameter is saved as the TREE_TYPE of
7986 // ARG.
7989 {
7992 }
7994 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
7995 because one of them is dependent. But we need to represent the
7996 conversion for the benefit of cp_tree_equal. */
7998 static tree
8000 {
8001 /* Auto parms get no conversion. */
8004 /* We don't need or want to add this conversion now if we're going to use the
8005 argument for deduction. */
8017 }
8019 /* Convert the indicated template ARG as necessary to match the
8020 indicated template PARM. Returns the converted ARG, or
8021 error_mark_node if the conversion was unsuccessful. Error and
8022 warning messages are issued under control of COMPLAIN. This
8023 conversion is for the Ith parameter in the parameter list. ARGS is
8024 the full set of template arguments deduced so far. */
8026 static tree
8028 tree arg,
8029 tree args,
8030 tsubst_flags_t complain,
8032 tree in_decl)
8033 {
8034 tree orig_arg;
8035 tree val;
8041 /* Trivially convert placeholders. */
8050 {
8051 /* The template argument was the name of some
8052 member function. That's usually
8053 invalid, but static members are OK. In any
8054 case, grab the underlying fields/functions
8055 and issue an error later if required. */
8057 }
8065 /* When determining whether an argument pack expansion is a template,
8066 look at the pattern. */
8070 /* Deal with an injected-class-name used as a template template arg. */
8072 {
8075 {
8085 }
8086 }
8088 is_tmpl_type =
8104 {
8106 {
8110 }
8113 "to refer to a type member of a template parameter, "
8118 typename_type,
8119 complain);
8122 }
8124 {
8126 {
8128 {
8133 {
8134 /* The template argument is a type, but we're expecting
8135 an expression. */
8140 /* [temp.arg]/2: "In a template-argument, an ambiguity
8141 between a type-id and an expression is resolved to a
8142 type-id, regardless of the form of the corresponding
8143 template-parameter." So give the user a clue. */
8146 "for non-type template parameter is treated as "
8148 }
8152 else
8155 }
8156 }
8158 }
8160 {
8162 {
8169 else
8172 }
8174 }
8177 /* We already did the appropriate conversion when packing args. */
8180 {
8182 {
8184 /* The number of argument required is not known yet.
8185 Just accept it for now. */
8187 else
8188 {
8190 tree argparm;
8192 /* Strip alias templates that are equivalent to another
8193 template. */
8199 args))
8200 {
8203 /* TEMPLATE_TEMPLATE_PARM node is preferred over
8204 TEMPLATE_DECL. */
8206 {
8211 }
8212 }
8213 else
8214 {
8216 {
8223 }
8226 }
8228 // Check that the constraints are compatible before allowing the
8229 // substitution.
8232 {
8234 {
8240 }
8242 }
8243 }
8244 }
8245 else
8247 /* We only form one instance of each template specialization.
8248 Therefore, if we use a non-canonical variant (i.e., a
8249 typedef), any future messages referring to the type will use
8250 the typedef, which is confusing if those future uses do not
8251 themselves also use the typedef. */
8254 }
8255 else
8256 {
8261 /* We don't have enough levels of args to do any substitution. This
8264 {
8268 }
8269 else
8280 /* We used to call digest_init here. However, digest_init
8281 will report errors, which we don't want when complain
8282 is zero. More importantly, digest_init will try too
8283 hard to convert things: for example, `0' should not be
8284 converted to pointer type at this point according to
8285 the standard. Accepting this is not merely an
8286 extension, since deciding whether or not these
8287 conversions can occur is part of determining which
8288 function template to call, or whether a given explicit
8289 argument specification is valid. */
8291 else
8292 {
8295 }
8306 {
8307 /* Reject template arguments that are references to built-in
8308 functions with no library fallbacks. */
8317 }
8320 {
8321 /* Strip typedefs from the SCOPE_REF. */
8324 complain);
8327 }
8328 }
8331 }
8333 /* Coerces the remaining template arguments in INNER_ARGS (from
8334 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
8335 Returns the coerced argument pack. PARM_IDX is the position of this
8336 parameter in the template parameter list. ARGS is the original
8337 template argument list. */
8338 static tree
8341 tree args,
8342 tree inner_args,
8344 tree new_args,
8346 tree in_decl,
8347 tsubst_flags_t complain)
8348 {
8351 tree packed_args;
8352 tree argument_pack;
8359 {
8360 /* When the template parameter is a non-type template parameter pack
8361 or template template parameter pack whose type or template
8362 parameters use parameter packs, we know exactly how many arguments
8363 we are looking for. Build a vector of the instantiated decls for
8364 these template parameters in PACKED_PARMS. */
8365 /* We can't use make_pack_expansion here because it would interpret a
8366 _DECL as a use rather than a declaration. */
8380 /* If we're doing a partial instantiation of a member template,
8381 verify that all of the types used for the non-type
8382 template parameter pack are, in fact, valid for non-type
8383 template parameters. */
8386 {
8389 {
8394 }
8395 /* We don't know how many args we have yet, just
8396 use the unconverted ones for now. */
8398 }
8401 }
8402 /* Check if we have a placeholder pack, which indicates we're
8403 in the context of a introduction list. In that case we want
8404 to match this pack to the single placeholder. */
8408 {
8411 }
8412 else
8415 /* Convert the remaining arguments, which will be a part of the
8416 parameter pack "parm". */
8419 {
8425 {
8426 /* Once we've packed as many args as we have types, stop. */
8430 /* We don't know how many args we have yet, just
8431 use the unconverted ones for now. */
8433 else
8435 }
8438 {
8441 }
8442 else
8445 in_decl);
8449 }
8453 {
8458 }
8463 else
8464 {
8467 }
8474 }
8476 /* Returns the number of pack expansions in the template argument vector
8477 ARGS. */
8479 static int
8481 {
8486 {
8490 }
8492 }
8494 /* Convert all template arguments to their appropriate types, and
8495 return a vector containing the innermost resulting template
8496 arguments. If any error occurs, return error_mark_node. Error and
8497 warning messages are issued under control of COMPLAIN.
8499 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8500 for arguments not specified in ARGS. Otherwise, if
8501 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
8502 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
8503 USE_DEFAULT_ARGS is false, then all arguments must be specified in
8504 ARGS. */
8506 static tree
8508 tree args,
8509 tree in_decl,
8510 tsubst_flags_t complain,
8513 {
8515 tree orig_inner_args;
8516 tree inner_args;
8517 tree new_args;
8518 tree new_inner_args;
8520 /* When used as a boolean value, indicates whether this is a
8521 variadic template parameter list. Since it's an int, we can also
8522 subtract it from nparms to get the number of non-variadic
8523 parameters. */
8528 /* Adjustment to nparms for fixed parameter packs. */
8533 /* Likewise for parameters with default arguments. */
8541 /* Determine if there are any parameter packs or default arguments. */
8543 {
8551 }
8554 /* If there are no parameters that follow a parameter pack, we need to
8555 expand any argument packs so that we can deduce a parameter pack from
8556 some non-packed args followed by an argument pack, as in variadic85.C.
8557 If there are such parameters, we need to leave argument packs intact
8558 so the arguments are assigned properly. This can happen when dealing
8559 with a nested class inside a partial specialization of a class
8560 template, as in variadic92.C, or when deducing a template parameter pack
8561 from a sub-declarator, as in variadic114.C. */
8565 /* Count any pack expansion args. */
8571 && require_all_args
8572 && !variadic_args_p
8573 && (!use_default_args
8576 {
8577 bad_nargs:
8579 {
8581 {
8585 }
8586 else
8593 }
8596 }
8597 /* We can't pass a pack expansion to a non-pack parameter of an alias
8598 template (DR 1430). */
8602 && variadic_args_p
8604 {
8606 {
8608 {
8614 {
8617 "pack expansion argument for non-pack parameter "
8619 else
8621 "pack expansion argument for non-pack parameter "
8625 }
8626 }
8628 found:;
8629 }
8631 }
8633 /* We need to evaluate the template arguments, even though this
8634 template-id may be nested within a "sizeof". */
8635 cp_evaluated ev;
8641 {
8642 tree arg;
8643 tree parm;
8645 /* Get the Ith template parameter. */
8649 {
8652 }
8654 /* Calculate the next argument. */
8657 else
8663 {
8664 /* Some arguments will be placed in the
8665 template parameter pack PARM. */
8672 {
8673 /* We don't know how many args we have yet, just use the
8674 unconverted (and still packed) ones for now. */
8678 }
8682 /* Store this argument. */
8684 {
8685 lost++;
8686 /* We are done with all of the arguments. */
8689 }
8690 else
8691 {
8695 {
8698 }
8699 }
8702 }
8704 {
8706 {
8707 /* "If every valid specialization of a variadic template
8708 requires an empty template parameter pack, the template is
8709 ill-formed, no diagnostic required." So check that the
8710 pattern works with this parameter. */
8715 in_decl);
8717 {
8722 }
8724 /* Recover from missing typename. */
8728 /* We don't know how many args we have yet, just
8729 use the unconverted ones for now. */
8733 }
8734 }
8736 {
8737 /* There must be a default arg in this case. */
8740 /* The position of the first default template argument,
8741 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8742 Record that. */
8746 }
8747 else
8751 {
8754 }
8756 {
8757 /* This can occur if there was an error in the template
8758 parameter list itself (which we would already have
8759 reported) that we are trying to recover from, e.g., a class
8760 template with a parameter list such as
8761 template<typename..., typename> (cpp0x/variadic150.C). */
8764 /* This can also happen with a fixed parameter pack (71834). */
8767 }
8768 else
8774 lost++;
8777 }
8780 {
8781 /* If we had fixed parameter packs, we didn't know how many arguments we
8782 actually needed earlier; now we do. */
8786 }
8789 {
8790 /* We had some pack expansion arguments that will only work if the packs
8791 are empty, but wait until instantiation time to complain.
8792 See variadic-ttp3.C. */
8794 /* Except that we can't provide empty packs to alias templates or
8795 concepts when there are no corresponding parameters. Basically,
8796 we can get here with this:
8798 template<typename T> concept C = true;
8800 template<typename... Args>
8801 requires C<Args...>
8802 void f();
8804 When parsing C<Args...>, we try to form a concept check of
8805 C<?, Args...>. Without the extra check for substituting an empty
8806 pack past the last parameter, we can accept the check as valid.
8808 FIXME: This may be valid for alias templates (but I doubt it).
8810 FIXME: The error could be better also. */
8812 {
8817 }
8828 }
8831 {
8834 }
8841 }
8843 /* Convert all template arguments to their appropriate types, and
8844 return a vector containing the innermost resulting template
8845 arguments. If any error occurs, return error_mark_node. Error and
8846 warning messages are not issued.
8848 Note that no function argument deduction is performed, and default
8849 arguments are used to fill in unspecified arguments. */
8850 tree
8852 {
8854 }
8856 /* Convert all template arguments to their appropriate type, and
8857 instantiate default arguments as needed. This returns a vector
8858 containing the innermost resulting template arguments, or
8859 error_mark_node if unsuccessful. */
8860 tree
8862 tsubst_flags_t complain)
8863 {
8865 }
8867 /* Like coerce_template_parms. If PARMS represents all template
8868 parameters levels, this function returns a vector of vectors
8869 representing all the resulting argument levels. Note that in this
8870 case, only the innermost arguments are coerced because the
8871 outermost ones are supposed to have been coerced already.
8873 Otherwise, if PARMS represents only (the innermost) vector of
8874 parameters, this function returns a vector containing just the
8875 innermost resulting arguments. */
8877 static tree
8879 tree args,
8880 tree in_decl,
8881 tsubst_flags_t complain,
8884 {
8887 tree coerced_args;
8890 {
8892 tree level;
8898 {
8899 tree l;
8903 require_all_args,
8904 use_default_args);
8905 else
8912 }
8913 }
8914 else
8917 require_all_args,
8918 use_default_args);
8920 }
8922 /* Returns 1 if template args OT and NT are equivalent. */
8924 int
8926 {
8935 /* For member templates */
8944 {
8961 }
8965 {
8968 /* Don't treat an alias template specialization with dependent
8969 arguments as equivalent to its underlying type when used as a
8970 template argument; we need them to be distinct so that we
8971 substitute into the specialization arguments at instantiation
8972 time. And aliases can't be equivalent without being ==, so
8973 we don't need to look any deeper.
8975 During partial ordering, however, we need to treat them normally so
8976 that we can order uses of the same alias with different
8977 cv-qualification (79960). */
8981 else
8983 }
8986 else
8987 {
8988 /* Try to treat a template non-type argument that has been converted
8989 to the parameter type as equivalent to one that hasn't yet. */
9002 }
9003 }
9005 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
9006 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
9007 NEWARG_PTR with the offending arguments if they are non-NULL. */
9009 int
9013 {
9026 {
9031 {
9037 }
9038 }
9040 }
9044 {
9046 }
9048 /* Implement a freelist interface for objects of type T.
9050 Head is a separate object, rather than a regular member, so that we
9051 can define it as a GTY deletable pointer, which is highly
9052 desirable. A data member could be declared that way, but then the
9053 containing object would implicitly get GTY((user)), which would
9054 prevent us from instantiating freelists as global objects.
9055 Although this way we can create freelist global objects, they're
9056 such thin wrappers that instantiating temporaries at every use
9057 loses nothing and saves permanent storage for the freelist object.
9059 Member functions next, anew, poison and reinit have default
9060 implementations that work for most of the types we're interested
9061 in, but if they don't work for some type, they should be explicitly
9062 specialized. See the comments before them for requirements, and
9063 the example specializations for the tree_list_freelist. */
9065 class freelist
9066 {
9067 /* Return the next object in a chain. We could just do type
9068 punning, but if we access the object with its underlying type, we
9069 avoid strict-aliasing trouble. This needs only work between
9070 poison and reinit. */
9073 /* Return a newly allocated, uninitialized or minimally-initialized
9074 object of type T. Any initialization performed by anew should
9075 either remain across the life of the object and the execution of
9076 poison, or be redone by reinit. */
9079 /* Optionally scribble all over the bits holding the object, so that
9080 they become (mostly?) uninitialized memory. This is called while
9081 preparing to make the object part of the free list. */
9086 #ifdef ENABLE_GC_CHECKING
9087 /* Poison the data, to indicate the data is garbage. */
9090 #endif
9091 /* Let valgrind know the object is free. */
9094 /* Let valgrind know the next portion of the object is available,
9095 but uninitialized. */
9097 }
9099 /* Bring an object that underwent at least one lifecycle after anew
9100 and before the most recent free and poison, back to a usable
9101 state, reinitializing whatever is needed for it to be
9102 functionally equivalent to an object just allocated and returned
9103 by anew. This may poison or clear the next field, used by
9104 freelist housekeeping after poison was called. */
9108 #ifdef ENABLE_GC_CHECKING
9110 #endif
9111 /* Let valgrind know the entire object is available, but
9112 uninitialized. */
9114 }
9116 /* Reference a GTY-deletable pointer that points to the first object
9117 in the free list proper. */
9120 /* Construct a freelist object chaining objects off of HEAD. */
9123 /* Add OBJ to the free object list. The former head becomes OBJ's
9124 successor. */
9126 {
9130 }
9132 /* Take an object from the free list, if one is available, or
9133 allocate a new one. Objects taken from the free list should be
9134 regarded as filled with garbage, except for bits that are
9135 configured to be preserved across free and alloc. */
9137 {
9139 {
9144 }
9145 else
9147 }
9148 };
9150 /* Explicitly specialize the interfaces for freelist<tree_node>: we
9151 want to allocate a TREE_LIST using the usual interface, and ensure
9152 TREE_CHAIN remains functional. Alas, we have to duplicate a bit of
9153 build_tree_list logic in reinit, so this could go out of sync. */
9157 {
9159 }
9161 inline tree
9163 {
9165 }
9169 {
9175 #ifdef ENABLE_GC_CHECKING
9178 /* Poison the data, to indicate the data is garbage. */
9181 #endif
9182 /* Let valgrind know the object is free. */
9184 /* But we still want to use the TREE_CODE and TREE_CHAIN parts. */
9188 #ifdef ENABLE_GC_CHECKING
9190 /* Keep TREE_CHAIN functional. */
9192 #else
9194 #endif
9195 }
9199 {
9202 #ifdef ENABLE_GC_CHECKING
9206 #endif
9208 /* Let valgrind know the entire object is available, but
9209 uninitialized. */
9212 #ifdef ENABLE_GC_CHECKING
9214 #else
9216 #endif
9217 }
9219 /* Point to the first object in the TREE_LIST freelist. */
9221 /* Return the/an actual TREE_LIST freelist. */
9224 {
9226 }
9228 /* Point to the first object in the tinst_level freelist. */
9230 /* Return the/an actual tinst_level freelist. */
9233 {
9235 }
9237 /* Point to the first object in the pending_template freelist. */
9239 /* Return the/an actual pending_template freelist. */
9242 {
9244 }
9246 /* Build the TREE_LIST object out of a split list, store it
9247 permanently, and return it. */
9248 tree
9250 {
9259 }
9263 /* Increment OBJ's refcount unless it is already infinite. */
9266 {
9270 }
9272 /* Release storage for OBJ and node, if it's a TREE_LIST. */
9273 void
9275 {
9279 }
9281 /* Decrement OBJ's refcount if not infinite. If it reaches zero, release
9282 OBJ's DECL and OBJ, and start over with the tinst_level object that
9283 used to be referenced by OBJ's NEXT. */
9284 static void
9286 {
9290 {
9294 }
9295 }
9297 /* Modify PTR so that it points to OBJ, adjusting the refcounts of OBJ
9298 and of the former PTR. Omitting the second argument is equivalent
9299 to passing (T*)NULL; this is allowed because passing the
9300 zero-valued integral constant NULL confuses type deduction and/or
9301 overload resolution. */
9303 static void
9305 {
9309 }
9311 static void
9313 {
9323 /* We are called both from instantiate_decl, where we've already had a
9324 tinst_level pushed, and instantiate_template, where we haven't.
9325 Compensate. */
9327 level = !current_tinst_level
9339 else
9348 }
9351 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
9352 ARGLIST. Valid choices for FNS are given in the cp-tree.def
9353 documentation for TEMPLATE_ID_EXPR. */
9355 tree
9357 {
9364 {
9367 }
9370 {
9372 unknown_type_node,
9374 arglist);
9376 }
9379 }
9381 /* Within the scope of a template class S<T>, the name S gets bound
9382 (in build_self_reference) to a TYPE_DECL for the class, not a
9383 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
9384 or one of its enclosing classes, and that type is a template,
9385 return the associated TEMPLATE_DECL. Otherwise, the original
9386 DECL is returned.
9388 Also handle the case when DECL is a TREE_LIST of ambiguous
9389 injected-class-names from different bases. */
9391 tree
9393 {
9397 /* DR 176: A lookup that finds an injected-class-name (10.2
9398 [class.member.lookup]) can result in an ambiguity in certain cases
9399 (for example, if it is found in more than one base class). If all of
9400 the injected-class-names that are found refer to specializations of
9401 the same class template, and if the name is followed by a
9402 template-argument-list, the reference refers to the class template
9403 itself and not a specialization thereof, and is not ambiguous. */
9405 {
9408 {
9414 }
9417 else
9419 }
9425 }
9427 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
9428 parameters, find the desired type.
9430 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
9432 IN_DECL, if non-NULL, is the template declaration we are trying to
9433 instantiate.
9435 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
9436 the class we are looking up.
9438 Issue error and warning messages under control of COMPLAIN.
9440 If the template class is really a local class in a template
9441 function, then the FUNCTION_CONTEXT is the function in which it is
9442 being instantiated.
9444 ??? Note that this function is currently called *twice* for each
9445 template-id: the first time from the parser, while creating the
9446 incomplete type (finish_template_type), and the second type during the
9447 real instantiation (instantiate_template_class). This is surely something
9448 that we want to avoid. It also causes some problems with argument
9449 coercion (see convert_nontype_argument for more information on this). */
9451 static tree
9454 {
9456 tree t;
9459 spec_entry elt;
9460 hashval_t hash;
9463 {
9467 else
9468 {
9475 }
9478 }
9480 {
9483 /* If we are declaring a constructor, say A<T>::A<T>, we will get
9484 an implicit typename for the second A. Deal with it. */
9489 {
9492 }
9493 }
9496 {
9499 }
9501 {
9505 }
9507 {
9510 }
9512 /* Issue an error message if we didn't find a template. */
9514 {
9518 }
9521 /* Make sure it's a user visible template, if it was named by
9522 the user. */
9525 {
9527 {
9531 }
9533 }
9537 /* An alias that just changes the name of a template is equivalent to the
9538 other template, so if any of the arguments are pack expansions, strip
9539 the alias to avoid problems with a pack expansion passed to a non-pack
9540 alias template parameter (DR 1430). */
9545 {
9546 tree parm;
9555 }
9556 else
9557 {
9559 tree gen_tmpl;
9560 tree type_decl;
9568 /* An error occurred while building the template TEMPL, and a
9569 diagnostic has most certainly been emitted for that
9570 already. Let's propagate that error. */
9579 {
9580 /* We've been given an incomplete set of template arguments.
9581 For example, given:
9583 template <class T> struct S1 {
9584 template <class U> struct S2 {};
9585 template <class U> struct S2<U*> {};
9586 };
9588 we will be called with an ARGLIST of `U*', but the
9589 TEMPLATE will be `template <class T> template
9590 <class U> struct S1<T>::S2'. We must fill in the missing
9591 arguments. */
9595 }
9597 /* Now we should have enough arguments. */
9600 /* From here on, we're only interested in the most general
9601 template. */
9603 /* Calculate the BOUND_ARGS. These will be the args that are
9604 actually tsubst'd into the definition to create the
9605 instantiation. */
9607 complain,
9612 /* We were unable to bind the arguments. */
9615 /* In the scope of a template class, explicit references to the
9616 template class refer to the type of the template, not any
9617 instantiation of it. For example, in:
9619 template <class T> class C { void f(C<T>); }
9621 the `C<T>' is just the same as `C'. Outside of the
9622 class, however, such a reference is an instantiation. */
9626 {
9631 }
9633 /* If we already have this specialization, return it. */
9643 /* If the the template's constraints are not satisfied,
9644 then we cannot form a valid type.
9646 Note that the check is deferred until after the hash
9647 lookup. This prevents redundant checks on previously
9648 instantiated specializations. */
9650 {
9652 {
9653 auto_diagnostic_group d;
9656 }
9658 }
9662 /* If the deduced arguments are invalid, then the binding
9663 failed. */
9667 complain))
9674 {
9679 }
9683 {
9686 }
9687 else
9696 /* Create the type. */
9698 {
9699 /* The user referred to a specialization of an alias
9700 template represented by GEN_TMPL.
9702 [temp.alias]/2 says:
9704 When a template-id refers to the specialization of an
9705 alias template, it is equivalent to the associated
9706 type obtained by substitution of its
9707 template-arguments for the template-parameters in the
9708 type-id of the alias template. */
9711 /* Note that the call above (by indirectly calling
9712 register_specialization in tsubst_decl) registers the
9713 TYPE_DECL representing the specialization of the alias
9714 template. So next time someone substitutes ARGLIST for
9715 the template parms into the alias template (GEN_TMPL),
9716 she'll get that TYPE_DECL back. */
9720 }
9722 {
9724 {
9735 }
9736 else
9737 {
9738 /* We don't want to call start_enum for this type, since
9739 the values for the enumeration constants may involve
9740 template parameters. And, no one should be interested
9741 in the enumeration constants for such a type. */
9744 }
9748 }
9750 {
9751 /* Lambda closures are regenerated in tsubst_lambda_expr, not
9752 instantiated here. */
9760 /* A local class. Make sure the decl gets registered properly. */
9767 /* This instantiation is another name for the primary
9768 template type. Set the TYPE_CANONICAL field
9769 appropriately. */
9772 /* Some of the template arguments require structural
9773 equality testing, so this template class requires
9774 structural equality testing. */
9776 }
9777 else
9780 /* If we called start_enum or pushtag above, this information
9781 will already be set up. */
9783 {
9790 }
9791 else
9795 {
9801 {
9804 }
9805 }
9809 {
9813 {
9814 tree attributes
9822 }
9823 }
9825 /* Let's consider the explicit specialization of a member
9826 of a class template specialization that is implicitly instantiated,
9827 e.g.:
9828 template<class T>
9829 struct S
9830 {
9831 template<class U> struct M {}; //#0
9832 };
9834 template<>
9835 template<>
9836 struct S<int>::M<char> //#1
9837 {
9838 int i;
9839 };
9840 [temp.expl.spec]/4 says this is valid.
9842 In this case, when we write:
9843 S<int>::M<char> m;
9845 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
9846 the one of #0.
9848 When we encounter #1, we want to store the partial instantiation
9849 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
9851 For all cases other than this "explicit specialization of member of a
9852 class template", we just want to store the most general template into
9853 the CLASSTYPE_TI_TEMPLATE of M.
9855 This case of "explicit specialization of member of a class template"
9856 only happens when:
9857 1/ the enclosing class is an instantiation of, and therefore not
9858 the same as, the context of the most general template, and
9859 2/ we aren't looking at the partial instantiation itself, i.e.
9860 the innermost arguments are not the same as the innermost parms of
9861 the most general template.
9863 So it's only when 1/ and 2/ happens that we want to use the partial
9864 instantiation of the member template in lieu of its most general
9865 template. */
9869 /* the enclosing class must be an instantiation... */
9872 {
9876 tree partial_inst_args =
9883 use_partial_inst_tmpl =
9884 /*...and we must not be looking at the partial instantiation
9885 itself. */
9887 partial_inst_args);
9888 }
9891 /* This case is easy; there are no member templates involved. */
9893 else
9894 {
9895 /* This is a full instantiation of a member template. Find
9896 the partial instantiation of which this is an instance. */
9898 /* Temporarily reduce by one the number of levels in the ARGLIST
9899 so as to avoid comparing the last set of arguments. */
9903 /* FOUND is either a proper class type, or an alias
9904 template specialization. In the later case, it's a
9905 TYPE_DECL, resulting from the substituting of arguments
9906 for parameters in the TYPE_DECL of the alias template
9907 done earlier. So be careful while getting the template
9908 of FOUND. */
9910 ? found
9917 {
9918 /* If this partial instantiation is specialized, we want to
9919 use it for hash table lookup. */
9923 }
9924 }
9926 // Build template info for the new specialization.
9936 /* Note this use of the partial instantiation so we can check it
9937 later in maybe_process_partial_specialization. */
9944 /* Now that the type has been registered on the instantiations
9945 list, we set up the enumerators. Because the enumeration
9946 constants may involve the enumeration type itself, we make
9947 sure to register the type first, and then create the
9948 constants. That way, doing tsubst_expr for the enumeration
9949 constants won't result in recursive calls here; we'll find
9950 the instantiation and exit above. */
9954 /* If the type makes use of template parameters, the
9955 code that generates debugging information will crash. */
9958 /* Possibly limit visibility based on template args. */
9965 }
9966 }
9968 /* Wrapper for lookup_template_class_1. */
9970 tree
9973 {
9974 tree ret;
9980 }
9982 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
9984 tree
9986 {
9990 /* The type of the expression is NULL_TREE since the template-id could refer
9991 to an explicit or partial specialization. */
9993 }
9995 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9997 tree
9999 {
10013 {
10015 {
10016 auto_diagnostic_group d;
10019 }
10021 }
10024 }
10026 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
10027 TARGS template args, and instantiate it if it's not dependent. */
10029 tree
10031 tsubst_flags_t complain)
10032 {
10035 {
10038 }
10041 }
10043 \f
10044 struct pair_fn_data
10045 {
10046 tree_fn_t fn;
10047 tree_fn_t any_fn;
10049 /* True when we should also visit template parameters that occur in
10050 non-deduced contexts. */
10053 };
10055 /* Called from for_each_template_parm via walk_tree. */
10057 static tree
10059 {
10066 #define WALK_SUBTREE(NODE) \
10067 do \
10068 { \
10069 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
10070 pfd->include_nondeduced_p, \
10071 pfd->any_fn); \
10072 if (result) goto out; \
10073 } \
10074 while (0)
10084 {
10088 /* Fall through. */
10094 else
10104 /* Since we're not going to walk subtrees, we have to do this
10105 explicitly here. */
10107 /* Fall through. */
10110 /* Check the return type. */
10113 /* Check the parameter types. Since default arguments are not
10114 instantiated until they are needed, the TYPE_ARG_TYPES may
10115 contain expressions that involve template parameters. But,
10116 no-one should be looking at them yet. And, once they're
10117 instantiated, they don't contain template parameters, so
10118 there's no point in looking at them then, either. */
10119 {
10120 tree parm;
10125 /* Since we've already handled the TYPE_ARG_TYPES, we don't
10126 want walk_tree walking into them itself. */
10128 }
10131 {
10135 }
10154 /* Fall through. */
10166 /* Record template parameters such as `T' inside `TT<T>'. */
10168 /* Fall through. */
10180 /* A template template parameter is encountered. */
10184 /* Already substituted template template parameter */
10189 /* A template-id in a TYPENAME_TYPE might be a deduced context after
10190 partial instantiation. */
10202 /* If there's no type, then this thing must be some expression
10203 involving template parameters. */
10229 {
10233 /* Recursively walk the type of each constraint variable. */
10236 {
10239 }
10240 }
10245 }
10247 #undef WALK_SUBTREE
10249 /* We didn't find any template parameters we liked. */
10250 out:
10252 }
10254 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
10255 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
10256 call FN with the parameter and the DATA.
10257 If FN returns nonzero, the iteration is terminated, and
10258 for_each_template_parm returns 1. Otherwise, the iteration
10259 continues. If FN never returns a nonzero value, the value
10260 returned by for_each_template_parm is 0. If FN is NULL, it is
10261 considered to be the function which always returns 1.
10263 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
10264 parameters that occur in non-deduced contexts. When false, only
10265 visits those template parameters that can be deduced. */
10267 static tree
10271 tree_fn_t any_fn)
10272 {
10274 tree result;
10276 /* Set up. */
10282 /* Walk the tree. (Conceptually, we would like to walk without
10283 duplicates, but for_each_template_parm_r recursively calls
10284 for_each_template_parm, so we would need to reorganize a fair
10285 bit to use walk_tree_without_duplicates, so we keep our own
10286 visited list.) */
10289 else
10292 for_each_template_parm_r,
10296 /* Clean up. */
10298 {
10301 }
10304 }
10306 struct find_template_parameter_info
10307 {
10310 {}
10315 };
10317 /* Appends the declaration of T to the list in DATA. */
10319 static int
10321 {
10324 /* Template parameters declared within the expression are not part of
10325 the parameter mapping. For example, in this concept:
10327 template<typename T>
10328 concept C = requires { <expr> } -> same_as<int>;
10330 the return specifier same_as<int> declares a new decltype parameter
10331 that must not be part of the parameter mapping. The same is true
10332 for generic lambda parameters, lambda template parameters, etc. */
10339 /* Arguments like const T yield parameters like const T. This means that
10340 a template-id like X<T, const T> would yield two distinct parameters:
10341 T and const T. Adjust types to their unqualified versions. */
10347 }
10349 /* Ensure that we recursively examine certain terms that are not normally
10350 visited in for_each_template_parm_r. */
10352 static int
10354 {
10357 #define WALK_SUBTREE(NODE) \
10358 do \
10359 { \
10360 for_each_template_parm (NODE, keep_template_parm, data, \
10361 &ftpi->visited, true, \
10362 any_template_parm_r); \
10363 } \
10364 while (0)
10367 {
10371 /* Search for template parameters in type aliases. */
10373 {
10376 }
10380 /* Type constraints of a placeholder type may contain parameters. */
10387 /* Search through references to variable templates. */
10398 }
10400 /* Keep walking. */
10402 }
10404 /* Returns a list of unique template parameters found within T. */
10406 tree
10408 {
10417 }
10419 /* Returns true if T depends on any template parameter. */
10421 int
10423 {
10453 else
10454 {
10457 }
10462 }
10464 /* Returns true iff current_function_decl is an incompletely instantiated
10465 template. Useful instead of processing_template_decl because the latter
10466 is set to 0 during instantiate_non_dependent_expr. */
10468 bool
10470 {
10479 }
10481 /* Returns true if T depends on any template parameter with level LEVEL. */
10483 bool
10485 {
10488 }
10490 /* Returns true if the signature of DECL depends on any template parameter from
10491 its enclosing class. */
10493 bool
10495 {
10505 template_parm_outer_level,
10515 }
10517 /* Returns TRUE iff INST is an instantiation we don't need to do in an
10518 ill-formed translation unit, i.e. a variable or function that isn't
10519 usable in a constant expression. */
10523 {
10528 }
10530 /* Returns TRUE iff we should refuse to instantiate DECL because it's
10531 neglectable and instantiated from within an erroneous instantiation. */
10533 static bool
10535 {
10546 }
10554 /* We're starting to instantiate D; record the template instantiation context
10555 at LOC for diagnostics and to restore it later. */
10557 static bool
10559 {
10563 {
10564 /* Tell error.c not to try to instantiate any templates. */
10567 "template instantiation depth exceeds maximum of %d"
10569 max_tinst_depth);
10571 }
10573 /* If the current instantiation caused problems, don't let it instantiate
10574 anything else. Do allow deduction substitution and decls usable in
10575 constant expressions. */
10579 /* When not -quiet, dump template instantiations other than functions, since
10580 announce_function will take care of those. */
10601 }
10603 /* We're starting substitution of TMPL<ARGS>; record the template
10604 substitution context for diagnostics and to restore it later. */
10606 static bool
10608 {
10610 }
10612 /* We're starting to instantiate D; record INPUT_LOCATION and the
10613 template instantiation context for diagnostics and to restore it
10614 later. */
10616 bool
10618 {
10620 }
10622 /* Likewise, but record LOC as the program location. */
10624 bool
10626 {
10629 }
10631 /* We're done instantiating this template; return to the instantiation
10632 context. */
10634 void
10636 {
10637 /* Restore the filename and line number stashed away when we started
10638 this instantiation. */
10642 }
10644 /* We're instantiating a deferred template; restore the template
10645 instantiation context in which the instantiation was requested, which
10646 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
10648 static tree
10650 {
10662 }
10664 /* Returns the TINST_LEVEL which gives the original instantiation
10665 context. */
10669 {
10675 }
10677 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
10678 vector of template arguments, as for tsubst.
10680 Returns an appropriate tsubst'd friend declaration. */
10682 static tree
10684 {
10685 tree new_friend;
10690 /* This was a friend declared with an explicit template
10691 argument list, e.g.:
10693 friend void f<>(T);
10695 to indicate that f was a template instantiation, not a new
10696 function declaration. Now, we have to figure out what
10697 instantiation of what template. */
10698 {
10700 tree new_args;
10701 tree tmpl;
10704 /* Friend functions are looked up in the containing namespace scope.
10705 We must enter that scope, to avoid finding member functions of the
10706 current class with same name. */
10721 tsk_none);
10723 }
10727 /* The NEW_FRIEND will look like an instantiation, to the
10728 compiler, but is not an instantiation from the point of view of
10729 the language. For example, we might have had:
10731 template <class T> struct S {
10732 template <class U> friend void f(T, U);
10733 };
10735 Then, in S<int>, template <class U> void f(int, U) is not an
10736 instantiation of anything. */
10742 {
10747 /* Attach the template requirements to the new declaration
10748 for declaration matching. We need to rebuild the requirements
10749 so that parameter levels match. */
10751 {
10759 /* Update the constraints -- these won't really be valid for
10760 checking, but that's not what we need them for. These ensure
10761 that the declared function can find the friend during
10762 declaration matching. */
10767 /* Also update the template parameter list. */
10769 }
10770 }
10772 /* The mangled name for the NEW_FRIEND is incorrect. The function
10773 is not a template instantiation and should not be mangled like
10774 one. Therefore, we forget the mangling here; we'll recompute it
10775 later if we need it. */
10777 {
10780 }
10783 {
10784 tree old_decl;
10785 tree new_friend_template_info;
10786 tree new_friend_result_template_info;
10787 tree ns;
10790 /* We must save some information from NEW_FRIEND before calling
10791 duplicate decls since that function will free NEW_FRIEND if
10792 possible. */
10794 new_friend_is_defn =
10799 {
10800 /* This declaration is a `primary' template. */
10803 new_friend_result_template_info
10805 }
10806 else
10809 /* Inside pushdecl_namespace_level, we will push into the
10810 current namespace. However, the friend function should go
10811 into the namespace of the template. */
10821 {
10822 /* This new friend declaration matched an existing
10823 declaration. For example, given:
10825 template <class T> void f(T);
10826 template <class U> class C {
10827 template <class T> friend void f(T) {}
10828 };
10830 the friend declaration actually provides the definition
10831 of `f', once C has been instantiated for some type. So,
10832 old_decl will be the out-of-class template declaration,
10833 while new_friend is the in-class definition.
10835 But, if `f' was called before this point, the
10836 instantiation of `f' will have DECL_TI_ARGS corresponding
10837 to `T' but not to `U', references to which might appear
10838 in the definition of `f'. Previously, the most general
10839 template for an instantiation of `f' was the out-of-class
10840 version; now it is the in-class version. Therefore, we
10841 run through all specialization of `f', adding to their
10842 DECL_TI_ARGS appropriately. In particular, they need a
10843 new set of outer arguments, corresponding to the
10844 arguments for this class instantiation.
10846 The same situation can arise with something like this:
10848 friend void f(int);
10849 template <class T> class C {
10850 friend void f(T) {}
10851 };
10853 when `C<int>' is instantiated. Now, `f(int)' is defined
10854 in the class. */
10857 /* On the other hand, if the in-class declaration does
10858 *not* provide a definition, then we don't want to alter
10859 existing definitions. We can just leave everything
10860 alone. */
10861 ;
10862 else
10863 {
10867 /* Overwrite whatever template info was there before, if
10868 any, with the new template information pertaining to
10869 the declaration. */
10873 {
10874 /* We should have called reregister_specialization in
10875 duplicate_decls. */
10880 /* Instantiate it if the global has already been used. */
10884 }
10885 else
10886 {
10887 tree t;
10889 /* Indicate that the old function template is a partial
10890 instantiation. */
10898 /* Reassign any specializations already in the hash table
10899 to the new more general template, and add the
10900 additional template args. */
10904 {
10906 spec_entry elt;
10918 register_specialization
10921 }
10923 }
10924 }
10926 /* The information from NEW_FRIEND has been merged into OLD_DECL
10927 by duplicate_decls. */
10929 }
10930 }
10931 else
10932 {
10936 /* In the code
10937 template <class T> class C {
10938 template <class U> friend void C1<U>::f (); // case 1
10939 friend void C2<T>::f (); // case 2
10940 };
10941 we only need to make sure CONTEXT is a complete type for
10942 case 2. To distinguish between the two cases, we note that
10943 CONTEXT of case 1 remains dependent type after tsubst while
10944 this isn't true for case 2. */
10954 {
10956 /* do_friend adds the TEMPLATE_DECL for any member friend
10957 template even if it isn't a member template, i.e.
10958 template <class T> friend A<T>::f();
10959 Look through it in that case. */
10963 /* Check to see that the declaration is really present, and,
10964 possibly obtain an improved declaration. */
10969 }
10970 }
10973 }
10975 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
10976 template arguments, as for tsubst.
10978 Returns an appropriate tsubst'd friend type or error_mark_node on
10979 failure. */
10981 static tree
10983 {
10984 tree tmpl;
10987 {
10990 }
10995 else
10996 {
10999 }
11006 {
11007 /* The friend template has already been declared. Just
11008 check to see that the declarations match, and install any new
11009 default parameters. We must tsubst the default parameters,
11010 of course. We only need the innermost template parameters
11011 because that is all that redeclare_class_template will look
11012 at. */
11015 {
11023 }
11024 }
11025 else
11026 {
11027 /* The friend template has not already been declared. In this
11028 case, the instantiation of the template class will cause the
11029 injection of this template into the namespace scope. */
11033 {
11034 /* The new TMPL is not an instantiation of anything, so we
11035 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
11036 for the new type because that is supposed to be the
11037 corresponding template decl, i.e., TMPL. */
11044 /* It is hidden. */
11049 /* Inject this template into the enclosing namspace scope. */
11051 }
11052 }
11056 else
11060 }
11062 /* Returns zero if TYPE cannot be completed later due to circularity.
11063 Otherwise returns one. */
11065 static int
11067 {
11077 else
11079 }
11084 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
11085 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
11087 static tree
11090 {
11099 {
11106 clauses
11110 else
11112 }
11113 /* If the first attribute argument is an identifier, don't
11114 pass it through tsubst. Attributes like mode, format,
11115 cleanup and several target specific attributes expect it
11116 unmodified. */
11118 {
11119 tree chain
11124 }
11126 {
11127 /* An attribute pack expansion. */
11136 {
11140 }
11142 }
11143 else
11150 }
11152 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
11153 unchanged or a new TREE_LIST chain. */
11155 static tree
11158 {
11163 {
11167 }
11171 {
11174 {
11177 {
11183 }
11184 }
11186 }
11189 }
11191 /* Apply any attributes which had to be deferred until instantiation
11192 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
11193 ARGS, COMPLAIN, IN_DECL are as tsubst. */
11195 static void
11198 {
11200 tree t;
11207 {
11211 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
11212 to our attributes parameter. */
11214 }
11215 else
11216 {
11218 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
11219 lookup_template_class_1, and should be preserved. */
11223 }
11227 {
11231 }
11235 {
11240 {
11243 {
11249 }
11250 else
11252 }
11255 }
11256 }
11258 /* Perform (or defer) access check for typedefs that were referenced
11259 from within the template TMPL code.
11260 This is a subroutine of instantiate_decl and instantiate_class_template.
11261 TMPL is the template to consider and TARGS is the list of arguments of
11262 that template. */
11264 static void
11266 {
11276 {
11288 /* Make access check error messages point to the location
11289 of the use of the typedef. */
11293 tf_warning_or_error);
11294 }
11295 }
11297 static tree
11299 {
11301 tree typedecl;
11302 tree pbinfo;
11303 tree base_list;
11305 tree fn_context;
11314 /* Figure out which template is being instantiated. */
11318 /* Mark the type as in the process of being defined. */
11321 /* We may be in the middle of deferred access check. Disable
11322 it now. */
11325 /* Determine what specialization of the original template to
11326 instantiate. */
11331 {
11332 /* This TYPE is actually an instantiation of a partial
11333 specialization. We replace the innermost set of ARGS with
11334 the arguments appropriate for substitution. For example,
11335 given:
11337 template <class T> struct S {};
11338 template <class T> struct S<T*> {};
11340 and supposing that we are instantiating S<int*>, ARGS will
11341 presently be {int*} -- but we need {int}. */
11344 }
11345 else
11346 {
11349 }
11351 /* If the template we're instantiating is incomplete, then clearly
11352 there's nothing we can do. */
11354 {
11355 /* We can try again later. */
11358 }
11360 /* If we've recursively instantiated too many templates, stop. */
11368 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
11373 else
11374 {
11377 }
11378 /* Use #pragma pack from the template context. */
11384 /* Set the input location to the most specialized template definition.
11385 This is needed if tsubsting causes an error. */
11397 {
11400 /* Adjust visibility for template arguments. */
11402 }
11408 /* We should never instantiate a nested class before its enclosing
11409 class; we need to look up the nested class by name before we can
11410 instantiate it, and that lookup should instantiate the enclosing
11411 class. */
11417 {
11418 tree pbase_binfo;
11419 tree pushed_scope;
11422 /* We must enter the scope containing the type, as that is where
11423 the accessibility of types named in dependent bases are
11424 looked up from. */
11427 /* Substitute into each of the bases to determine the actual
11428 basetypes. */
11430 {
11431 tree base;
11437 {
11438 expanded_bases =
11445 }
11448 {
11450 /* Extract the already-expanded base class. */
11452 else
11453 /* Substitute to figure out the base class. */
11455 NULL_TREE);
11463 }
11464 }
11466 /* The list is now in reverse order; correct that. */
11471 }
11472 /* Now call xref_basetypes to set up all the base-class
11473 information. */
11481 /* Now that our base classes are set up, enter the scope of the
11482 class, so that name lookups into base classes, etc. will work
11483 correctly. This is precisely analogous to what we do in
11484 begin_class_definition when defining an ordinary non-template
11485 class, except we also need to push the enclosing classes. */
11488 /* Now members are processed in the order of declaration. */
11491 {
11495 {
11497 {
11499 /* A closure type for a lambda in an NSDMI or default argument.
11500 Ignore it; it will be regenerated when needed. */
11503 /* Build new CLASSTYPE_NESTED_UTDS. */
11505 tree newtag;
11511 /* If the member is a class template, then -- even after
11512 substitution -- there may be dependent types in the
11513 template argument list for the class. We increment
11514 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
11515 that function will assume that no types are dependent
11516 when outside of a template. */
11526 {
11530 /* Unfortunately, lookup_template_class sets
11531 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
11532 instantiation (i.e., for the type of a member
11533 template class nested within a template class.)
11534 This behavior is required for
11535 maybe_process_partial_specialization to work
11536 correctly, but is not accurate in this case;
11537 the TAG is not an instantiation of anything.
11538 (The corresponding TEMPLATE_DECL is an
11539 instantiation, but the TYPE is not.) */
11542 /* Now, we call pushtag to put this NEWTAG into the scope of
11543 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
11544 pushtag calling push_template_decl. We don't have to do
11545 this for enums because it will already have been done in
11546 tsubst_enum. */
11550 }
11551 }
11553 {
11554 tree r;
11563 /* Instantiate members marked with attribute used. */
11569 }
11572 /* A closure type for a lambda in an NSDMI or default argument.
11574 else
11575 {
11576 /* Build new TYPE_FIELDS. */
11578 {
11579 tree condition;
11582 condition =
11592 }
11594 {
11595 tree r;
11599 /* The file and line for this declaration, to
11600 assist in error message reporting. Since we
11601 called push_tinst_level above, we don't need to
11602 restore these. */
11612 {
11613 /* A capture pack became multiple fields. */
11616 }
11619 {
11623 {
11624 /* In [temp.inst]:
11626 [t]he initialization (and any associated
11627 side-effects) of a static data member does
11628 not occur unless the static data member is
11629 itself used in a way that requires the
11630 definition of the static data member to
11631 exist.
11633 Therefore, we do not substitute into the
11634 initialized for the static data member here. */
11635 finish_static_data_member_decl
11641 /* Instantiate members marked with attribute used. */
11644 }
11646 {
11647 /* Determine whether R has a valid type and can be
11648 completed later. If R is invalid, then its type
11649 is replaced by error_mark_node. */
11655 {
11656 /* If R's type couldn't be completed and
11657 it isn't a flexible array member (whose
11658 type is incomplete by definition) give
11659 an error. */
11662 }
11667 {
11670 }
11671 }
11673 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
11674 such a thing will already have been added to the field
11675 list by tsubst_enum in finish_member_declaration in the
11676 CLASSTYPE_NESTED_UTDS case above. */
11680 {
11683 }
11684 }
11685 }
11686 }
11687 }
11688 else
11689 {
11692 {
11693 /* Build new CLASSTYPE_FRIEND_CLASSES. */
11699 {
11700 /* template <class T> friend class C; */
11703 }
11705 {
11706 /* template <class T> friend class C::D; */
11712 }
11715 {
11716 /* This could be either
11718 friend class T::C;
11720 when dependent_type_p is false or
11722 template <class U> friend class T::C;
11724 otherwise. */
11725 /* Bump processing_template_decl in case this is something like
11726 template <class T> friend struct A<T>::B. */
11733 }
11737 {
11738 /* friend class C;
11740 where C hasn't been declared yet. Let's lookup name
11741 from namespace scope directly, bypassing any name that
11742 come from dependent base class. */
11745 /* The call to xref_tag_from_type does injection for friend
11746 classes. */
11748 friend_type =
11752 }
11754 /* friend class C<T>; */
11757 /* Otherwise it's
11759 friend class C;
11761 where C is already declared or
11763 friend class C<int>;
11765 We don't have to do anything in these cases. */
11768 /* Trick make_friend_class into realizing that the friend
11769 we're adding is a template, not an ordinary class. It's
11770 important that we use make_friend_class since it will
11771 perform some error-checking and output cross-reference
11772 information. */
11780 }
11781 else
11782 {
11783 /* Build new DECL_FRIENDLIST. */
11784 tree r;
11786 /* The file and line for this declaration, to
11787 assist in error message reporting. Since we
11788 called push_tinst_level above, we don't need to
11789 restore these. */
11793 {
11796 }
11801 {
11804 }
11805 }
11806 }
11807 }
11810 {
11811 /* Restore these before substituting into the lambda capture
11812 initializers. */
11815 }
11817 /* Set the file and line number information to whatever is given for
11818 the class itself. This puts error messages involving generated
11819 implicit functions at a predictable point, and the same point
11820 that would be used for non-template classes. */
11827 /* We don't instantiate default arguments for member functions. 14.7.1:
11829 The implicit instantiation of a class template specialization causes
11830 the implicit instantiation of the declarations, but not of the
11831 definitions or default arguments, of the class member functions,
11832 member classes, static data members and member templates.... */
11834 /* Some typedefs referenced from within the template code need to be access
11835 checked at template instantiation time, i.e now. These types were
11836 added to the template at parsing time. Let's get those and perform
11837 the access checks then. */
11846 /* The vtable for a template class can be emitted in any translation
11847 unit in which the class is instantiated. When there is no key
11848 method, however, finish_struct_1 will already have added TYPE to
11849 the keyed_classes. */
11854 }
11856 /* Wrapper for instantiate_class_template_1. */
11858 tree
11860 {
11861 tree ret;
11866 }
11868 tree
11870 {
11871 tree r;
11877 else
11878 {
11885 }
11888 }
11890 /* Given a function parameter pack TMPL_PARM and some function parameters
11891 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
11892 and set *SPEC_P to point at the next point in the list. */
11894 tree
11896 {
11897 /* Collect all of the extra "packed" parameters into an
11898 argument pack. */
11899 tree parmvec;
11909 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
11913 {
11918 }
11920 /* Build the argument packs. */
11925 }
11927 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
11928 NONTYPE_ARGUMENT_PACK. */
11930 static tree
11932 {
11934 }
11936 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
11937 pack expansion with no extra args, 2 if it has extra args, or 0
11938 if it is not a pack expansion. */
11940 static int
11942 {
11944 /* We're being called before this happens in tsubst_pack_expansion. */
11951 /* A decl pack is itself an expansion. */
11958 }
11961 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
11963 static tree
11965 {
11972 }
11974 /* This is a subroutine of tsubst_pack_expansion.
11976 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
11977 mechanism to store the (non complete list of) arguments of the
11978 substitution and return a non substituted pack expansion, in order
11979 to wait for when we have enough arguments to really perform the
11980 substitution. */
11982 static bool
11986 {
11987 /* If one pack has an expansion and another pack has a normal
11988 argument or if one pack has an empty argument and an another
11989 one hasn't then tsubst_pack_expansion cannot perform the
11990 substitution and need to fall back on the
11991 PACK_EXPANSION_EXTRA mechanism. */
11999 {
12002 parm_pack;
12004 {
12009 /* We can't substitute a pack expansion with extra args into
12010 our pattern. */
12014 else
12016 }
12020 }
12022 }
12024 /* [temp.variadic]/6 says that:
12026 The instantiation of a pack expansion [...]
12027 produces a list E1,E2, ..., En, where N is the number of elements
12028 in the pack expansion parameters.
12030 This subroutine of tsubst_pack_expansion produces one of these Ei.
12032 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
12033 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
12034 PATTERN, and each TREE_VALUE is its corresponding argument pack.
12035 INDEX is the index 'i' of the element Ei to produce. ARGS,
12036 COMPLAIN, and IN_DECL are the same parameters as for the
12037 tsubst_pack_expansion function.
12039 The function returns the resulting Ei upon successful completion,
12040 or error_mark_node.
12042 Note that this function possibly modifies the ARGS parameter, so
12043 it's the responsibility of the caller to restore it. */
12045 static tree
12047 tree parm_packs,
12049 tree args /* This parm gets
12051 tsubst_flags_t complain,
12052 tree in_decl)
12053 {
12054 tree t;
12057 /* For each parameter pack, change the substitution of the parameter
12058 pack to the ith argument in its argument pack, then expand the
12059 pattern. */
12061 {
12066 ith_elem_is_expansion |=
12069 /* Select the Ith argument from the pack. */
12073 {
12075 {
12080 }
12081 else
12083 }
12084 else
12085 {
12090 {
12092 /* Update the corresponding argument. */
12094 }
12095 else
12096 /* Re-use the ARGUMENT_PACK_SELECT. */
12098 }
12100 }
12102 /* Substitute into the PATTERN with the (possibly altered)
12103 arguments. */
12105 /* Expanding a fixed parameter pack from
12106 coerce_template_parameter_pack. */
12113 else
12116 /* If the Ith argument pack element is a pack expansion, then
12117 the Ith element resulting from the substituting is going to
12118 be a pack expansion as well. */
12123 }
12125 /* When the unexpanded parameter pack in a fold expression expands to an empty
12126 sequence, the value of the expression is as follows; the program is
12127 ill-formed if the operator is not listed in this table.
12129 && true
12130 || false
12131 , void() */
12133 tree
12135 {
12139 {
12148 }
12154 }
12156 /* Given a fold-expression T and a current LEFT and RIGHT operand,
12157 form an expression that combines the two terms using the
12158 operator of T. */
12160 static tree
12162 {
12166 // Handle compound assignment operators.
12171 {
12179 complain);
12180 }
12181 }
12183 /* Substitute ARGS into the pack of a fold expression T. */
12187 {
12189 }
12191 /* Substitute ARGS into the pack of a fold expression T. */
12195 {
12197 }
12199 /* Expand a PACK of arguments into a grouped as left fold.
12200 Given a pack containing elements A0, A1, ..., An and an
12201 operator @, this builds the expression:
12203 ((A0 @ A1) @ A2) ... @ An
12205 Note that PACK must not be empty.
12207 The operator is defined by the original fold expression T. */
12209 static tree
12211 {
12214 {
12217 }
12219 }
12221 /* Substitute into a unary left fold expression. */
12223 static tree
12225 tree in_decl)
12226 {
12231 {
12235 }
12238 else
12240 }
12242 /* Substitute into a binary left fold expression.
12244 Do ths by building a single (non-empty) vector of argumnts and
12245 building the expression from those elements. */
12247 static tree
12249 tree in_decl)
12250 {
12259 {
12264 }
12272 }
12274 /* Expand a PACK of arguments into a grouped as right fold.
12275 Given a pack containing elementns A0, A1, ..., and an
12276 operator @, this builds the expression:
12278 A0@ ... (An-2 @ (An-1 @ An))
12280 Note that PACK must not be empty.
12282 The operator is defined by the original fold expression T. */
12284 tree
12286 {
12287 // Build the expression.
12291 {
12294 }
12296 }
12298 /* Substitute into a unary right fold expression. */
12300 static tree
12302 tree in_decl)
12303 {
12308 {
12312 }
12315 else
12317 }
12319 /* Substitute into a binary right fold expression.
12321 Do ths by building a single (non-empty) vector of arguments and
12322 building the expression from those elements. */
12324 static tree
12326 tree in_decl)
12327 {
12336 {
12341 }
12350 }
12352 /* Walk through the pattern of a pack expansion, adding everything in
12353 local_specializations to a list. */
12355 class el_data
12356 {
12359 tree extra;
12360 tsubst_flags_t complain;
12364 };
12365 static tree
12367 {
12373 /* Remember local typedefs (85214). */
12379 {
12381 /* Don't mess with variables declared within the pattern. */
12384 {
12385 /* Maybe pull out the PARM_DECL for a partial instantiation. */
12388 {
12394 }
12396 {
12397 /* Handle lambda capture here, since we aren't doing any
12398 substitution now, and so tsubst_copy won't call
12399 process_outer_var_ref. */
12403 {
12409 {
12410 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
12411 proxies. */
12413 {
12418 }
12420 }
12421 }
12422 }
12423 }
12427 }
12429 }
12430 static tree
12432 {
12436 }
12438 /* Extract any uses of local_specializations from PATTERN and add them to ARGS
12439 for use in PACK_EXPANSION_EXTRA_ARGS. */
12441 tree
12443 {
12449 }
12451 /* Apply any local specializations from PACK_EXPANSION_EXTRA_ARGS and add the
12452 normal template args to ARGS. */
12454 tree
12456 {
12458 {
12460 {
12461 /* The partial instantiation involved local declarations collected in
12462 extract_local_specs; map from the general template to our local
12463 context. */
12469 /* else inst is already a full instantiation of the pack. */
12471 }
12474 }
12476 }
12478 /* Substitute ARGS into T, which is an pack expansion
12479 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
12480 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
12481 (if only a partial substitution could be performed) or
12482 ERROR_MARK_NODE if there was an error. */
12483 tree
12485 tree in_decl)
12486 {
12487 tree pattern;
12492 tree result;
12500 /* Add in any args remembered from an earlier partial instantiation. */
12505 /* Determine the argument packs that will instantiate the parameter
12506 packs used in the expansion expression. While we're at it,
12507 compute the number of arguments to be expanded and make sure it
12508 is consistent. */
12511 {
12518 {
12524 complain);
12525 else
12529 }
12531 {
12533 {
12536 parm_pack);
12538 }
12541 }
12543 {
12544 /* We know we have correct local_specializations if this
12545 expansion is at function scope, or if we're dealing with a
12546 local parameter in a requires expression; for the latter,
12547 tsubst_requires_expr set it up appropriately. */
12550 else
12551 /* We can't rely on local_specializations for a parameter
12552 name used later in a function declaration (such as in a
12553 late-specified return type). Even if it exists, it might
12554 have the wrong value for a recursive call. */
12558 {
12559 /* This parameter pack was used in an unevaluated context. Just
12560 make a dummy decl, since it's only used for its type. */
12565 /* Partial instantiation of the parm_pack, we can't build
12566 up an argument pack yet. */
12568 else
12570 }
12572 /* This argument pack isn't fully instantiated yet. We set this
12573 flag rather than clear arg_pack because we do want to do the
12574 optimization below, and we don't want to substitute directly
12575 into the pattern (as that would expose a NONTYPE_ARGUMENT_PACK
12576 where it isn't expected). */
12578 }
12580 {
12584 }
12585 else
12586 {
12591 }
12598 /* This can only happen if we forget to expand an argument
12599 pack somewhere else. Just return an error, silently. */
12600 {
12604 }
12607 {
12611 /* Don't bother trying to do a partial substitution with
12612 incomplete packs; we'll try again after deduction. */
12620 {
12625 pattern);
12626 else
12628 pattern);
12630 }
12632 /* Keep track of the parameter packs and their corresponding
12633 argument packs. */
12636 }
12637 else
12638 {
12639 /* We can't substitute for this parameter pack. We use a flag as
12640 well as the missing_level counter because function parameter
12641 packs don't have a level. */
12643 {
12645 }
12648 }
12649 }
12651 /* If the expansion is just T..., return the matching argument pack, unless
12652 we need to call convert_from_reference on all the elements. This is an
12653 important optimization; see c++/68422. */
12656 {
12659 /* If the argument pack is a single pack expansion, pull it out. */
12664 /* Types need no adjustment, nor does sizeof..., and if we still have
12665 some pack expansion args we won't do anything yet. */
12670 /* Also optimize expression pack expansions if we can tell that the
12671 elements won't have reference type. */
12677 /* Otherwise use the normal path so we get convert_from_reference. */
12678 }
12680 /* We cannot expand this expansion expression, because we don't have
12681 all of the argument packs we need. */
12683 {
12684 /* We got some full packs, but we can't substitute them in until we
12685 have values for all the packs. So remember these until then. */
12691 }
12693 {
12694 /* There were no real arguments, we're just replacing a parameter
12695 pack with another version of itself. Substitute into the
12696 pattern and return a PACK_EXPANSION_*. The caller will need to
12697 deal with that. */
12701 else
12705 }
12710 {
12711 /* We're in a late-specified return type, so create our own local
12712 specializations map; the current map is either NULL or (in the
12713 case of recursive unification) might have bindings that we don't
12714 want to use or alter. */
12717 }
12719 /* For each argument in each argument pack, substitute into the
12720 pattern. */
12724 {
12726 i,
12728 in_decl);
12731 {
12734 }
12735 }
12737 /* Update ARGS to restore the substitution from parameter packs to
12738 their argument packs. */
12740 {
12747 else
12748 {
12756 /* Update the corresponding argument. */
12760 else
12762 }
12763 }
12766 {
12769 }
12771 /* If the dependent pack arguments were such that we end up with only a
12772 single pack expansion again, there's no need to keep it in a TREE_VEC. */
12778 }
12780 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
12781 TMPL. We do this using DECL_PARM_INDEX, which should work even with
12782 parameter packs; all parms generated from a function parameter pack will
12783 have the same DECL_PARM_INDEX. */
12785 tree
12787 {
12789 tree patparm;
12792 {
12798 }
12799 else
12800 {
12805 }
12808 }
12810 /* Make an argument pack out of the TREE_VEC VEC. */
12812 static tree
12814 {
12815 tree pack;
12819 else
12820 {
12823 }
12826 }
12828 /* Return an exact copy of template args T that can be modified
12829 independently. */
12831 static tree
12833 {
12841 {
12846 }
12852 }
12854 /* Substitute ARGS into the *_ARGUMENT_PACK orig_arg. */
12856 tree
12858 tree in_decl)
12859 {
12860 /* Substitute into each of the arguments. */
12869 else
12876 }
12878 /* Substitute ARGS into the vector or list of template arguments T. */
12880 tree
12882 {
12894 {
12896 tree new_arg;
12901 {
12902 /* Substitute into an expansion expression. */
12906 /* Add to the expanded length adjustment the number of
12907 expanded arguments. We subtract one from this
12908 measurement, because the argument pack expression
12909 itself is already counted as 1 in
12910 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
12911 the argument pack is empty. */
12913 }
12916 else
12925 }
12930 /* Make space for the expanded arguments coming from template
12931 argument packs. */
12933 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
12934 arguments for a member template.
12935 In that case each TREE_VEC in ORIG_T represents a level of template
12936 arguments, and ORIG_T won't carry any non defaulted argument count.
12937 It will rather be the nested TREE_VECs that will carry one.
12938 In other words, ORIG_T carries a non defaulted argument count only
12939 if it doesn't contain any nested TREE_VEC. */
12941 {
12945 }
12947 {
12951 {
12954 /* Now expand the template argument pack "in place". */
12957 }
12958 else
12959 {
12961 out++;
12962 }
12963 }
12966 }
12968 /* Substitute ARGS into one level PARMS of template parameters. */
12970 static tree
12972 {
12979 {
12987 }
12990 }
12992 /* Return the result of substituting ARGS into the template parameters
12993 given by PARMS. If there are m levels of ARGS and m + n levels of
12994 PARMS, then the result will contain n levels of PARMS. For
12995 example, if PARMS is `template <class T> template <class U>
12996 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
12997 result will be `template <int*, double, class V>'. */
12999 static tree
13001 {
13005 /* When substituting into a template, we must set
13006 PROCESSING_TEMPLATE_DECL as the template parameters may be
13007 dependent if they are based on one-another, and the dependency
13008 predicates are short-circuit outside of templates. */
13015 {
13022 }
13027 }
13029 /* Return the result of substituting ARGS into one template parameter
13030 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
13031 parameter and which TREE_PURPOSE is the default argument of the
13032 template parameter. */
13034 static tree
13036 {
13061 }
13063 /* Substitute the ARGS into the indicated aggregate (or enumeration)
13064 type T. If T is not an aggregate or enumeration type, it is
13065 handled as if by tsubst. IN_DECL is as for tsubst. If
13066 ENTERING_SCOPE is nonzero, T is the context for a template which
13067 we are presently tsubst'ing. Return the substituted value. */
13069 static tree
13071 tree args,
13072 tsubst_flags_t complain,
13073 tree in_decl,
13075 {
13080 {
13085 /* Fall through. */
13089 {
13090 tree argvec;
13091 tree context;
13092 tree r;
13094 /* In "sizeof(X<I>)" we need to evaluate "I". */
13095 cp_evaluated ev;
13097 /* First, determine the context for the type we are looking
13098 up. */
13101 {
13104 /* If context is a nested class inside a class template,
13105 it may still need to be instantiated (c++/33959). */
13107 }
13109 /* Then, figure out what arguments are appropriate for the
13110 type we are trying to find. For example, given:
13112 template <class T> struct S;
13113 template <class T, class U> void f(T, U) { S<U> su; }
13115 and supposing that we are instantiating f<int, double>,
13116 then our ARGS will be {int, double}, but, when looking up
13117 S we only want {double}. */
13122 else
13123 {
13127 }
13130 }
13131 else
13132 /* This is not a template type, so there's nothing to do. */
13137 }
13138 }
13142 /* Substitute into the default argument ARG (a default argument for
13143 FN), which has the indicated TYPE. */
13145 tree
13147 tsubst_flags_t complain)
13148 {
13151 /* This can happen in invalid code. */
13169 /* This default argument came from a template. Instantiate the
13170 default argument here, not in tsubst. In the case of
13171 something like:
13173 template <class T>
13174 struct S {
13175 static T t();
13176 void f(T = t());
13177 };
13179 we must be careful to do name lookup in the scope of S<T>,
13180 rather than in the current class. */
13186 /* The default argument expression may cause implicitly defined
13187 member functions to be synthesized, which will result in garbage
13188 collection. We must treat this situation as if we were within
13189 the body of function so as to avoid collecting live data on the
13190 stack. */
13199 /* Make sure the default argument is reasonable. */
13212 {
13216 }
13219 }
13221 /* Substitute into all the default arguments for FN. */
13223 static void
13225 {
13226 tree arg;
13227 tree tmpl_args;
13231 /* If this function is not yet instantiated, we certainly don't need
13232 its default arguments. */
13235 /* Don't do this again for clones. */
13241 arg;
13247 complain);
13248 }
13250 /* Hash table mapping a FUNCTION_DECL to its dependent explicit-specifier. */
13253 /* Store a pair to EXPLICIT_SPECIFIER_MAP. */
13255 void
13257 {
13262 }
13264 /* Lookup an element in EXPLICIT_SPECIFIER_MAP. */
13266 static tree
13268 {
13270 }
13272 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
13274 static tree
13276 tree lambda_fntype)
13277 {
13282 /* Nobody should be tsubst'ing into non-template functions. */
13286 {
13287 /* If T is not dependent, just return it. */
13292 /* Calculate the most general template of which R is a
13293 specialization. */
13296 /* We're substituting a lambda function under tsubst_lambda_expr but not
13297 directly from it; find the matching function we're already inside.
13298 But don't do this if T is a generic lambda with a single level of
13299 template parms, as in that case we're doing a normal instantiation. */
13305 /* Calculate the complete set of arguments used to
13306 specialize R. */
13308 (DECL_TEMPLATE_RESULT
13314 /* Check to see if we already have this specialization. */
13316 {
13320 }
13322 /* We can see more levels of arguments than parameters if
13323 there was a specialization of a member template, like
13324 this:
13326 template <class T> struct S { template <class U> void f(); }
13327 template <> template <class U> void S<int>::f(U);
13329 Here, we'll be substituting into the specialization,
13330 because that's where we can find the code we actually
13331 want to generate, but we'll have enough arguments for
13332 the most general template.
13334 We also deal with the peculiar case:
13336 template <class T> struct S {
13337 template <class U> friend void f();
13338 };
13339 template <class U> void f() {}
13340 template S<int>;
13341 template void f<double>();
13343 Here, the ARGS for the instantiation of will be {int,
13344 double}. But, we only need as many ARGS as there are
13345 levels of template parameters in CODE_PATTERN. We are
13346 careful not to get fooled into reducing the ARGS in
13347 situations like:
13349 template <class T> struct S { template <class U> void f(U); }
13350 template <class T> template <> void S<T>::f(int) {}
13352 which we can spot because the pattern will be a
13353 specialization in this case. */
13360 }
13361 else
13362 {
13363 /* This special case arises when we have something like this:
13365 template <class T> struct S {
13366 friend void f<int>(int, double);
13367 };
13369 Here, the DECL_TI_TEMPLATE for the friend declaration
13370 will be an IDENTIFIER_NODE. We are being called from
13371 tsubst_friend_function, and we want only to create a
13372 new decl (R) with appropriate types so that we can call
13373 determine_specialization. */
13376 }
13393 /* If we hit excessive deduction depth, the type is bogus even if
13394 it isn't error_mark_node, so don't build a decl. */
13398 /* We do NOT check for matching decls pushed separately at this
13399 point, as they may not represent instantiations of this
13400 template, and in any case are considered separate under the
13401 discrete model. */
13405 /* Clear out the mangled name and RTL for the instantiation. */
13408 /* Leave DECL_INITIAL set on deleted instantiations. */
13413 /* Handle explicit(dependent-expr). */
13415 {
13422 }
13424 /* OpenMP UDRs have the only argument a reference to the declared
13425 type. We want to diagnose if the declared type is a reference,
13426 which is invalid, but as references to references are usually
13427 quietly merged, diagnose it here. */
13429 {
13430 tree argtype
13435 "reference type %qT in "
13439 argtype);
13440 }
13443 /* Type-conversion operator. Reconstruct the name, in
13444 case it's the name of one of the template's parameters. */
13454 {
13458 }
13465 /* If this is an instantiation of a function with internal
13466 linkage, we already know what object file linkage will be
13467 assigned to the instantiation. */
13476 /* We'll re-clone as appropriate in instantiate_template. */
13479 /* If we aren't complaining now, return on error before we register
13480 the specialization so that we'll complain eventually. */
13486 /* Associate the constraints directly with the instantiation. We
13487 don't substitute through the constraints; that's only done when
13488 they are checked. */
13497 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
13498 this in the special friend case mentioned above where
13499 GEN_TMPL is NULL. */
13501 {
13506 tree new_r
13509 /* We instantiated this while substituting into
13510 the type earlier (template/friend54.C). */
13513 /* We're not supposed to instantiate default arguments
13514 until they are called, for a template. But, for a
13515 declaration like:
13517 template <class T> void f ()
13518 { extern void g(int i = T()); }
13520 we should do the substitution when the template is
13521 instantiated. We handle the member function case in
13522 instantiate_class_template since the default arguments
13523 might refer to other members of the class. */
13528 }
13529 else
13532 /* Copy the list of befriending classes. */
13536 {
13540 }
13543 {
13547 /* If this is an instantiation of a member template, clone it.
13548 If it isn't, that'll be handled by
13549 clone_constructors_and_destructors. */
13552 }
13558 /* Possibly limit visibility based on template args. */
13561 {
13565 }
13574 }
13576 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
13578 static tree
13580 tree lambda_fntype)
13581 {
13582 /* We can get here when processing a member function template,
13583 member class template, or template template parameter. */
13586 tree spec;
13587 tree tmpl_args;
13588 tree full_args;
13589 tree r;
13593 {
13594 /* Template template parameter is treated here. */
13598 /* If we get a real template back, return it. This can happen in
13599 the context of most_specialized_partial_spec. */
13602 else
13603 /* The new TEMPLATE_DECL was built in
13604 reduce_template_parm_level. */
13607 }
13610 {
13611 /* We might already have an instance of this template.
13612 The ARGS are for the surrounding class type, so the
13613 full args contain the tsubst'd args for the context,
13614 plus the innermost args from the template decl. */
13618 /* Because this is a template, the arguments will still be
13619 dependent, even after substitution. If
13620 PROCESSING_TEMPLATE_DECL is not set, the dependency
13621 predicates will short-circuit. */
13629 /* If this is a default template template argument,
13630 tsubst might not have changed anything. */
13637 {
13639 /* Type partial instantiations are stored as the type by
13640 lookup_template_class_1, not here as the template. */
13643 }
13644 }
13646 /* Make a new template decl. It will be similar to the
13647 original, but will record the current template arguments.
13648 We also create a new function declaration, which is just
13649 like the old one, but points to this new template, rather
13650 than the old one. */
13655 // Build new template info linking to the original template decl.
13657 {
13660 }
13661 else
13664 /* The template parameters for this new template are all the
13665 template parameters for the old template, except the
13666 outermost level of parameters. */
13669 complain);
13673 {
13674 tree new_type;
13682 /* For a partial specialization, we need to keep pointing to
13683 the primary template. */
13689 }
13690 else
13691 {
13692 tree new_decl;
13696 else
13706 {
13709 }
13710 else
13711 {
13714 }
13715 }
13725 /* Record this non-type partial instantiation. */
13731 }
13733 /* True if FN is the op() for a lambda in an uninstantiated template. */
13735 bool
13737 {
13742 }
13744 /* True if FN is the substitution (via tsubst_lambda_expr) of a function for
13745 which the above is true. */
13747 bool
13749 {
13755 }
13757 /* We're instantiating a variable from template function TCTX. Return the
13758 corresponding current enclosing scope. This gets complicated because lambda
13759 functions in templates are regenerated rather than instantiated, but generic
13760 lambda functions are subsequently instantiated. */
13762 static tree
13764 {
13774 {
13785 {
13789 }
13793 }
13795 }
13797 /* Substitute the ARGS into the T, which is a _DECL. Return the
13798 result of the substitution. Issue error and warning messages under
13799 control of COMPLAIN. */
13801 static tree
13803 {
13804 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
13805 location_t saved_loc;
13810 /* Set the filename and linenumber to improve error-reporting. */
13815 {
13825 {
13833 {
13834 /* If there is a local specialization that isn't a
13835 parameter pack, it means that we're doing a "simple"
13836 substitution from inside tsubst_pack_expansion. Just
13837 return the local specialization (which will be a single
13838 parm). */
13845 /* Expand the TYPE_PACK_EXPANSION that provides the types for
13846 the parameters in this function parameter pack. */
13850 {
13853 /* Zero-length parameter packs are boring. Just substitute
13854 into the chain. */
13858 }
13859 else
13860 {
13861 /* All we did was update the type. Make a note of that. */
13864 }
13865 }
13867 /* Loop through all of the parameters we'll build. When T is
13868 a function parameter pack, LEN is the number of expanded
13869 types in EXPANDED_TYPES; otherwise, LEN is 1. */
13872 {
13879 /* We're on the Ith parameter of the function parameter
13880 pack. */
13881 {
13882 /* Get the Ith type. */
13885 /* Rename the parameter to include the index. */
13888 }
13890 /* We're dealing with a normal parameter. */
13898 {
13901 else
13904 }
13914 /* Keep track of the first new parameter we
13915 generate. That's what will be returned to the
13916 caller. */
13920 /* Build a proper chain of parameters when substituting
13921 into a function parameter pack. */
13924 }
13926 /* If cp_unevaluated_operand is set, we're just looking for a
13927 single dummy parameter, so don't keep going. */
13932 /* FIRST_R contains the start of the chain we've built. */
13934 }
13938 {
13945 {
13946 /* This field is a lambda capture pack. Return a TREE_VEC of
13947 the expanded fields to instantiate_class_template_1. */
13951 {
13954 }
13955 else
13956 {
13957 /* All we did was update the type. Make a note of that. */
13960 }
13961 }
13964 {
13967 {
13971 }
13981 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
13982 number of bits. */
13988 {
13989 /* Set up DECL_TEMPLATE_INFO so that we can get at the
13990 NSDMI in perform_member_init. Still set DECL_INITIAL
13991 so that we know there is one. */
13996 }
13997 /* We don't have to set DECL_CONTEXT here; it is set by
13998 finish_member_declaration. */
14006 }
14010 }
14014 /* We reach here only for member using decls. We also need to check
14015 uses_template_parms because DECL_DEPENDENT_P is not set for a
14016 using-declaration that designates a member of the current
14017 instantiation (c++/53549). */
14020 {
14024 {
14029 {
14033 {
14036 }
14037 else
14038 {
14041 }
14043 }
14044 }
14045 else
14046 {
14052 else
14053 {
14056 }
14057 }
14058 }
14059 else
14060 {
14063 }
14068 {
14071 tree spec;
14073 tree ctx;
14082 {
14083 /* If this is the canonical decl, we don't have to
14084 mess with instantiations, and often we can't (for
14085 typename, template type parms and such). Note that
14086 TYPE_NAME is not correct for the above test if
14087 we've copied the type for a typedef. */
14093 }
14095 /* Check to see if we already have the specialization we
14096 need. */
14099 {
14100 /* T is a static data member or namespace-scope entity.
14101 We have to substitute into namespace-scope variables
14102 (not just variable templates) because of cases like:
14104 template <class T> void f() { extern T t; }
14106 where the entity referenced is not known until
14107 instantiation time. */
14111 {
14113 complain,
14115 /* If CTX is unchanged, then T is in fact the
14116 specialization we want. That situation occurs when
14117 referencing a static data member within in its own
14118 class. We can use pointer equality, rather than
14119 same_type_p, because DECL_CONTEXT is always
14120 canonical... */
14122 /* ... unless T is a member template; in which
14123 case our caller can be willing to create a
14124 specialization of that template represented
14125 by T. */
14129 }
14132 {
14137 argvec = (coerce_innermost_template_parms
14145 }
14146 }
14147 else
14148 {
14149 /* A local variable. */
14151 /* Subsequent calls to pushdecl will fill this in. */
14153 /* Unless this is a reference to a static variable from an
14154 enclosing function, in which case we need to fill it in now. */
14156 {
14160 }
14162 }
14163 /* If we already have the specialization we need, there is
14164 nothing more to do. */
14166 {
14169 }
14171 /* Create a new node for the specialization we need. */
14173 {
14176 else
14184 {
14185 /* Mask off any template args past the variable's context so we
14186 don't replace the auto with an unrelated argument. */
14190 /* This should never happen with the new lambda instantiation
14191 model, but keep the handling just in case. */
14194 }
14196 /* Substituting the type might have recursively instantiated this
14197 same alias (c++/86171). */
14200 {
14203 }
14204 }
14207 {
14213 {
14214 /* It may seem that this case cannot occur, since:
14216 typedef void f();
14217 void g() { f x; }
14219 declares a function, not a variable. However:
14221 typedef void f();
14222 template <typename T> void g() { T t; }
14223 template void g<f>();
14225 is an attempt to declare a variable with function
14226 type. */
14228 /* R is not yet sufficiently initialized, so we
14229 just use its name. */
14232 }
14234 /* Wait until cp_finish_decl to set this again, to handle
14235 circular dependency (template/instantiate6.C). */
14240 {
14245 {
14248 }
14250 }
14254 }
14260 /* Clear out the mangled name and RTL for the instantiation. */
14264 /* The initializer must not be expanded until it is required;
14265 see [temp.inst]. */
14269 {
14275 /* Possibly limit visibility based on template args. */
14278 {
14282 }
14284 }
14287 {
14288 /* A static data member declaration is always marked
14289 external when it is declared in-class, even if an
14290 initializer is present. We mimic the non-template
14291 processing here. */
14298 /* Remember whether we require constant initialization of
14299 a non-constant template variable. */
14304 }
14305 else
14306 {
14311 }
14319 /* Preserve a typedef that names a type. */
14321 {
14325 /* An alias template specialization can be dependent
14326 even if its underlying type is not. */
14328 }
14331 }
14336 }
14337 #undef RETURN
14339 out:
14340 /* Restore the file and line information. */
14344 }
14346 /* Substitute into the complete parameter type list PARMS. */
14348 tree
14350 tree args,
14351 tsubst_flags_t complain,
14352 tree in_decl)
14353 {
14355 }
14357 /* Substitute into the ARG_TYPES of a function type.
14358 If END is a TREE_CHAIN, leave it and any following types
14359 un-substituted. */
14361 static tree
14363 tree args,
14364 tree end,
14365 tsubst_flags_t complain,
14366 tree in_decl)
14367 {
14368 tree remaining_arg_types;
14372 tree default_arg;
14383 {
14384 /* For a pack expansion, perform substitution on the
14385 entire expression. Later on, we'll handle the arguments
14386 one-by-one. */
14391 /* So that we'll spin through the parameters, one by one. */
14393 else
14394 {
14395 /* We only partially substituted into the parameter
14396 pack. Our type is TYPE_PACK_EXPANSION. */
14399 }
14400 }
14413 {
14415 {
14419 }
14421 }
14422 /* DR 657. */
14426 /* Do array-to-pointer, function-to-pointer conversion, and ignore
14427 top-level qualifiers as required. */
14430 /* We do not substitute into default arguments here. The standard
14431 mandates that they be instantiated only when needed, which is
14432 done in build_over_call. */
14435 /* Except that we do substitute default arguments under tsubst_lambda_expr,
14436 since the new op() won't have any associated template arguments for us
14437 to refer to later. */
14443 {
14444 /* We've instantiated a template before its default arguments
14445 have been parsed. This can happen for a nested template
14446 class, and is not an error unless we require the default
14447 argument in a call of this function. */
14448 remaining_arg_types =
14451 remaining_arg_types);
14452 }
14453 else
14454 remaining_arg_types =
14456 }
14459 }
14461 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
14462 *not* handle the exception-specification for FNTYPE, because the
14463 initial substitution of explicitly provided template parameters
14464 during argument deduction forbids substitution into the
14465 exception-specification:
14467 [temp.deduct]
14469 All references in the function type of the function template to the
14470 corresponding template parameters are replaced by the specified tem-
14471 plate argument values. If a substitution in a template parameter or
14472 in the function type of the function template results in an invalid
14473 type, type deduction fails. [Note: The equivalent substitution in
14474 exception specifications is done only when the function is instanti-
14475 ated, at which point a program is ill-formed if the substitution
14476 results in an invalid type.] */
14478 static tree
14480 tree args,
14481 tsubst_flags_t complain,
14482 tree in_decl)
14483 {
14484 tree return_type;
14486 tree fntype;
14488 /* The TYPE_CONTEXT is not used for function/method types. */
14491 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
14492 failure. */
14496 {
14497 /* Substitute the argument types. */
14509 {
14510 /* DR 1207: 'this' is in scope in the trailing return type. */
14512 }
14514 /* Substitute the return type. */
14518 {
14521 }
14522 }
14523 else
14524 /* Substitute the return type. */
14529 /* DR 486 clarifies that creation of a function type with an
14530 invalid return type is a deduction failure. */
14533 {
14535 {
14538 else
14540 }
14542 }
14543 /* And DR 657. */
14548 {
14549 /* Substitute the argument types. */
14554 }
14556 /* Construct a new type node and return it. */
14558 {
14561 }
14562 else
14563 {
14565 /* Don't pick up extra function qualifiers from the basetype. */
14568 {
14569 /* [temp.deduct]
14571 Type deduction may fail for any of the following
14572 reasons:
14574 -- Attempting to create "pointer to member of T" when T
14575 is not a class type. */
14578 r);
14580 }
14584 }
14587 /* See comment above. */
14593 }
14595 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
14596 ARGS into that specification, and return the substituted
14597 specification. If there is no specification, return NULL_TREE. */
14599 static tree
14601 tree args,
14602 tsubst_flags_t complain,
14603 tree in_decl,
14605 {
14606 tree specs;
14607 tree new_specs;
14612 {
14613 /* A noexcept-specifier. */
14618 {
14619 /* Defer instantiation of noexcept-specifiers to avoid
14620 excessive instantiations (c++/49107). */
14623 {
14624 /* We already partially instantiated this member template,
14625 so combine the new args with the old. */
14630 }
14631 else
14632 {
14635 }
14636 }
14637 else
14638 {
14640 {
14642 args);
14644 }
14645 new_specs = tsubst_copy_and_build
14648 }
14650 }
14652 {
14655 else
14657 {
14658 tree spec;
14663 {
14664 /* Expand the pack expansion type. */
14667 in_decl);
14673 else
14674 {
14675 /* We're substituting into a member template, so
14676 we got a TYPE_PACK_EXPANSION back. Add that
14677 expansion and move on. */
14681 expanded_specs,
14682 complain);
14685 }
14686 }
14689 {
14692 else
14697 complain);
14698 }
14701 }
14702 }
14704 }
14706 /* Take the tree structure T and replace template parameters used
14707 therein with the argument vector ARGS. IN_DECL is an associated
14708 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
14709 Issue error and warning messages under control of COMPLAIN. Note
14710 that we must be relatively non-tolerant of extensions here, in
14711 order to preserve conformance; if we allow substitutions that
14712 should not be allowed, we may allow argument deductions that should
14713 not succeed, and therefore report ambiguous overload situations
14714 where there are none. In theory, we could allow the substitution,
14715 but indicate that it should have failed, and allow our caller to
14716 make sure that the right thing happens, but we don't try to do this
14717 yet.
14719 This function is used for dealing with types, decls and the like;
14720 for expressions, use tsubst_expr or tsubst_copy. */
14722 tree
14724 {
14747 else
14752 /* Reuse typedefs. We need to do this to handle dependent attributes,
14753 such as attribute aligned. */
14756 {
14760 {
14761 /* DECL represents an alias template and we want to
14762 instantiate it. */
14766 }
14770 {
14774 }
14779 else
14780 /* The typedef is from a non-template context. */
14784 {
14786 r = cp_build_qualified_type_real
14790 }
14791 else
14792 {
14793 /* We don't have an instantiation yet, so drop the typedef. */
14798 }
14799 }
14816 {
14842 {
14848 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
14849 needed. */
14855 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
14856 with TREE_SIDE_EFFECTS that indicates this is not an integral
14857 constant expression. */
14860 {
14863 }
14866 }
14872 {
14878 /* Early in template argument deduction substitution, we don't
14879 want to reduce the level of 'auto', or it will be confused
14880 with a normal template parm in subsequent deduction. */
14892 {
14895 /* See through ARGUMENT_PACK_SELECT arguments. */
14898 }
14903 {
14905 /* If ARG is an argument pack, we don't actually want to
14906 perform a substitution here, because substitutions
14907 for argument packs are only done
14908 element-by-element. We can get to this point when
14909 substituting the type of a non-type template
14910 parameter pack, when that type actually contains
14911 template parameter packs from an outer template, e.g.,
14913 template<typename... Types> struct A {
14914 template<Types... Values> struct B { };
14915 }; */
14919 {
14922 /* When building concept checks for the purpose of
14923 deducing placeholders, we can end up with wildcards
14924 where types are expected. Adjust this to the deduced
14925 value. */
14933 return cp_build_qualified_type_real
14935 }
14937 {
14938 /* We are processing a type constructed from a
14939 template template parameter. */
14950 /* Consider this code:
14952 template <template <class> class Template>
14953 struct Internal {
14954 template <class Arg> using Bind = Template<Arg>;
14955 };
14957 template <template <class> class Template, class Arg>
14958 using Instantiate = Template<Arg>; //#0
14960 template <template <class> class Template,
14961 class Argument>
14962 using Bind =
14963 Instantiate<Internal<Template>::template Bind,
14964 Argument>; //#1
14966 When #1 is parsed, the
14967 BOUND_TEMPLATE_TEMPLATE_PARM representing the
14968 parameter `Template' in #0 matches the
14969 UNBOUND_CLASS_TEMPLATE representing the argument
14970 `Internal<Template>::template Bind'; We then want
14971 to assemble the type `Bind<Argument>' that can't
14972 be fully created right now, because
14973 `Internal<Template>' not being complete, the Bind
14974 template cannot be looked up in that context. So
14975 we need to "store" `Bind<Argument>' for later
14976 when the context of Bind becomes complete. Let's
14977 store that in a TYPENAME_TYPE. */
14981 argvec),
14982 typename_type,
14983 complain);
14985 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
14986 are resolving nested-types in the signature of a
14987 member function templates. Otherwise ARG is a
14988 TEMPLATE_DECL and is the real template to be
14989 instantiated. */
14997 complain);
14998 return cp_build_qualified_type_real
15000 }
15003 else
15004 /* TEMPLATE_PARM_INDEX. */
15006 }
15009 /* This can happen during the attempted tsubst'ing in
15010 unify. This means that we don't yet have any information
15011 about the template parameter in question. */
15014 /* If we get here, we must have been looking at a parm for a
15015 more deeply nested template. Make a new version of this
15016 template parameter, but with a lower level. */
15018 {
15023 {
15025 r = cp_build_qualified_type_real
15029 }
15036 /* Break infinite recursion when substituting the constraints
15045 /* Cache the simple case of lowering a type parameter. */
15047 else
15048 {
15059 {
15060 /* Propagate constraints on placeholders since they are
15061 only instantiated during satisfaction. */
15065 {
15068 }
15069 }
15072 /* We have reduced the level of the template
15073 template parameter, but not the levels of its
15074 template parameters, so canonical_type_parameter
15075 will not be able to find the canonical template
15076 template parameter for this level. Thus, we
15077 require structural equality checking to compare
15078 TEMPLATE_TEMPLATE_PARMs. */
15082 else
15086 {
15088 /* We might need to substitute into the types of non-type
15089 template parameters. */
15101 }
15102 }
15106 /* OK, now substitute the type of the non-type parameter. We
15107 couldn't do it earlier because it might be an auto parameter,
15108 and we wouldn't need to if we had an argument. */
15117 }
15120 }
15123 {
15131 {
15135 }
15138 {
15142 }
15145 {
15149 }
15155 }
15158 /* We should never be tsubsting a binfo. */
15162 /* A vector of template arguments. */
15168 {
15172 /* [temp.deduct]
15174 Type deduction may fail for any of the following
15175 reasons:
15177 -- Attempting to create a pointer to reference type.
15178 -- Attempting to create a reference to a reference type or
15179 a reference to void.
15181 Core issue 106 says that creating a reference to a reference
15182 during instantiation is no longer a cause for failure. We
15183 only enforce this check in strict C++98 mode. */
15187 {
15190 /* We keep track of the last time we issued this error
15191 message to avoid spewing a ton of messages during a
15192 single bad template instantiation. */
15195 {
15200 else
15203 }
15206 }
15210 {
15212 {
15215 type);
15216 else
15218 type);
15219 }
15221 }
15223 {
15227 }
15229 /* In C++0x, during template argument substitution, when there is an
15230 attempt to create a reference to a reference type, reference
15231 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
15233 "If a template-argument for a template-parameter T names a type
15234 that is a reference to a type A, an attempt to create the type
15235 'lvalue reference to cv T' creates the type 'lvalue reference to
15236 A,' while an attempt to create the type type rvalue reference to
15237 cv T' creates the type T"
15238 */
15239 r = cp_build_reference_type
15242 else
15247 /* Will this ever be needed for TYPE_..._TO values? */
15251 }
15253 {
15256 {
15257 /* [temp.deduct]
15259 Type deduction may fail for any of the following
15260 reasons:
15262 -- Attempting to create "pointer to member of T" when T
15263 is not a class type. */
15267 }
15269 {
15273 }
15275 {
15279 }
15282 {
15283 /* The type of the implicit object parameter gets its
15284 cv-qualifiers from the FUNCTION_TYPE. */
15285 tree memptr;
15286 tree method_type
15291 complain);
15292 }
15293 else
15296 complain);
15297 }
15300 {
15301 tree fntype;
15302 tree specs;
15307 /* Substitute the exception specification. */
15315 }
15317 {
15322 /* As an optimization, we avoid regenerating the array type if
15323 it will obviously be the same as T. */
15327 /* These checks should match the ones in create_array_type_for_decl.
15329 [temp.deduct]
15331 The deduction may fail for any of the following reasons:
15333 -- Attempting to create an array with an element type that
15334 is void, a function type, or a reference type, or [DR337]
15335 an abstract class type. */
15341 {
15345 }
15357 {
15360 }
15363 }
15366 {
15369 {
15375 {
15380 }
15382 }
15383 else
15395 {
15399 }
15401 {
15402 /* Normally, make_typename_type does not require that the CTX
15403 have complete type in order to allow things like:
15405 template <class T> struct S { typename S<T>::X Y; };
15407 But, such constructs have already been resolved by this
15408 point, so here CTX really should have complete type, unless
15409 it's a partial instantiation. */
15412 {
15416 }
15417 }
15424 {
15427 }
15430 {
15432 {
15436 else
15438 }
15440 {
15444 else
15446 }
15447 }
15449 return cp_build_qualified_type_real
15451 }
15454 {
15466 }
15469 {
15470 tree type;
15486 complain);
15487 }
15490 {
15491 tree type;
15510 else
15511 {
15515 /* In a template ~id could be either a complement expression
15516 or an unqualified-id naming a destructor; if instantiating
15517 it produces an expression, it's not an id-expression or
15518 member access. */
15521 }
15526 }
15529 {
15533 }
15537 {
15538 tree r;
15542 else
15550 }
15565 /* We should use one of the expression tsubsts for these codes. */
15571 }
15572 }
15574 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
15575 expression on the left-hand side of the "." or "->" operator. We
15576 only do the lookup if we had a dependent BASELINK. Otherwise we
15577 adjust it onto the instantiated heirarchy. */
15579 static tree
15582 {
15594 {
15601 }
15608 {
15614 /* Treat as-if non-dependent below. */
15619 {
15625 }
15629 }
15630 else
15631 /* We're going to overwrite pieces below, make a duplicate. */
15634 /* If lookup found a single function, mark it as used at this point.
15635 (If lookup found multiple functions the one selected later by
15636 overload resolution will be marked as used at that point.) */
15638 {
15644 /* We might have instantiated an auto function. */
15646 }
15649 {
15650 /* Add back the template arguments, if present. */
15655 /* Update the conversion operator type. */
15657 }
15663 {
15665 qualifying_scope,
15666 object_type);
15668 /* We need to call adjust_result_of_qualified_name_lookup in case the
15669 destructor names a base class, but we unset BASELINK_QUALIFIED_P
15670 so that we still get virtual function binding. */
15672 }
15675 }
15677 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
15678 true if the qualified-id will be a postfix-expression in-and-of
15679 itself; false if more of the postfix-expression follows the
15680 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
15681 of "&". */
15683 static tree
15687 {
15688 tree expr;
15689 tree scope;
15690 tree name;
15692 tree template_args;
15697 /* Figure out what name to look up. */
15700 {
15710 }
15711 else
15712 {
15715 }
15717 /* Substitute into the qualifying scope. When there are no ARGS, we
15718 are just trying to simplify a non-dependent expression. In that
15719 case the qualifying scope may be dependent, and, in any case,
15720 substituting will not help. */
15723 {
15726 }
15727 else
15731 {
15738 }
15741 {
15743 {
15744 /* A BIT_NOT_EXPR is used to represent a destructor. */
15746 {
15750 }
15751 else
15754 }
15755 else
15759 {
15761 {
15765 }
15767 }
15768 }
15771 {
15773 scope);
15774 /* Remember that there was a reference to this entity. */
15777 }
15780 {
15786 }
15789 {
15790 /* We may be repeating a check already done during parsing, but
15791 if it was well-formed and passed then, it will pass again
15792 now, and if it didn't, we wouldn't have got here. The case
15793 we want to catch is when we couldn't tell then, and can now,
15794 namely when templ prior to substitution was an
15795 identifier. */
15801 complain);
15802 else
15804 }
15810 {
15811 expr = (adjust_result_of_qualified_name_lookup
15813 expr = (finish_qualified_id_expr
15817 }
15819 /* Expressions do not generally have reference type. */
15821 /* However, if we're about to form a pointer-to-member, we just
15822 want the referenced member referenced. */
15830 }
15832 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
15833 initializer, DECL is the substituted VAR_DECL. Other arguments are as
15834 for tsubst. */
15836 static tree
15839 {
15848 {
15850 {
15852 {
15857 }
15858 }
15860 {
15861 /* If we had an initializer but it
15862 instantiated to nothing,
15863 value-initialize the object. This will
15864 only occur when the initializer was a
15865 pack expansion where the parameter packs
15866 used in that expansion were of length
15867 zero. */
15873 }
15874 }
15877 }
15879 /* Like tsubst, but deals with expressions. This function just replaces
15880 template parms; to finish processing the resultant expression, use
15881 tsubst_copy_and_build or tsubst_expr. */
15883 static tree
15885 {
15887 tree r;
15895 {
15900 {
15901 /* We get here for a use of 'this' in an NSDMI. */
15905 /* This can happen for a parameter name used later in a function
15906 declaration (such as in a late-specified return type). Just
15907 make a dummy decl, since it's only used for its type. */
15910 /* Give it the template pattern as its context; its true context
15911 hasn't been instantiated yet and this is good enough for
15912 mangling. */
15914 }
15923 {
15924 tree enum_type;
15925 tree v;
15929 /* There is no need to substitute into namespace-scope
15930 enumerators. */
15933 /* If ARGS is NULL, then T is known to be non-dependent. */
15937 /* Unfortunately, we cannot just call lookup_name here.
15938 Consider:
15940 template <int I> int f() {
15941 enum E { a = I };
15942 struct S { void g() { E e = a; } };
15943 };
15945 When we instantiate f<7>::S::g(), say, lookup_name is not
15946 clever enough to find f<7>::a. */
15947 enum_type
15957 /* We didn't find the name. That should never happen; if
15958 name-lookup found it during preliminary parsing, we
15959 should find it again here during instantiation. */
15961 }
15966 {
15967 tree ctx;
15972 {
15975 {
15979 }
15981 }
15982 }
15992 {
15995 {
15996 /* First try name lookup to find the instantiation. */
15999 {
16001 {
16002 /* During error-recovery we may find a non-variable,
16003 even an OVERLOAD: just bail out and avoid ICEs and
16004 duplicate diagnostics (c++/62207). */
16007 }
16009 {
16010 /* Make sure the one we found is the one we want. */
16014 }
16015 }
16019 else
16020 {
16021 /* This can happen for a variable used in a
16022 late-specified return type of a local lambda, or for a
16023 local static or constant. Building a new VAR_DECL
16024 should be OK in all those cases. */
16027 /* Avoid infinite recursion (79640). */
16030 {
16031 /* We can't call cp_finish_decl, so handle the
16032 initializer by hand. */
16047 }
16054 }
16055 /* Remember this for subsequent uses. */
16058 }
16061 }
16062 else
16086 {
16087 /* Template template argument like the following example need
16088 special treatment:
16090 template <template <class> class TT> struct C {};
16091 template <class T> struct D {
16092 template <class U> struct E {};
16093 C<E> c; // #1
16094 };
16095 D<int> d; // #2
16097 We are processing the template argument `E' in #1 for
16098 the template instantiation #2. Originally, `E' is a
16099 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
16100 have to substitute this with one having context `D<int>'. */
16104 {
16105 /* When rewriting a constructor into a deduction guide, a
16106 non-dependent name can become dependent, so memtmpl<args>
16107 becomes context::template memtmpl<args>. */
16111 }
16113 }
16114 else
16115 /* Ordinary template template argument. */
16120 {
16121 /* Handle location wrappers by substituting the wrapped node
16122 first, *then* reusing the resulting type. Doing the type
16123 first ensures that we handle template parameters and
16124 parameter pack expansions. */
16126 {
16130 }
16134 {
16135 /* Wrapper to make a C++20 template parameter object const. */
16138 {
16141 }
16142 else
16143 {
16146 }
16147 }
16148 /* We shouldn't see any other uses of these in templates. */
16150 }
16160 {
16164 }
16169 {
16178 /* We only want to compute the number of arguments. */
16181 else
16188 {
16190 /* Set TREE_USED for the benefit of -Wunused. */
16194 }
16202 {
16207 else
16214 else
16217 }
16218 else
16220 }
16222 {
16230 }
16231 /* Fall through */
16247 {
16254 }
16257 {
16258 tree object;
16259 tree name;
16264 {
16268 }
16271 {
16281 }
16286 in_decl);
16287 else
16290 }
16326 {
16330 }
16333 {
16338 }
16341 {
16345 }
16348 {
16356 }
16362 {
16369 }
16372 {
16379 }
16382 {
16389 }
16392 {
16393 /* Substituted template arguments */
16402 }
16405 {
16425 }
16450 /* Fall through. */
16453 {
16456 }
16457 else
16461 /* This is handled by tsubst_copy_and_build. */
16465 {
16469 }
16472 /* We shouldn't have built any of these during initial template
16473 generation. Instead, they should be built during instantiation
16474 in response to the saved STMT_IS_FULL_EXPR_P setting. */
16478 {
16488 }
16506 {
16507 /* Instantiate any typedefs in the type. */
16512 }
16515 /* These can sometimes show up in a partial instantiation, but never
16516 involve template parms. */
16532 /* ??? There's no point in copying it for now, but maybe some
16533 day it will contain more information, such as a pointer back
16534 to the containing function, inlined copy or so. */
16538 /* We shouldn't get here, but keep going if !flag_checking. */
16542 }
16543 }
16545 /* Helper function for tsubst_omp_clauses, used for instantiation of
16546 OMP_CLAUSE_DECL of clauses. */
16548 static tree
16551 {
16555 /* Handle OpenMP iterators. */
16559 {
16560 tree ret;
16563 else
16564 {
16568 {
16583 }
16587 }
16591 }
16593 /* Handle an OpenMP array section represented as a TREE_LIST (or
16594 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
16595 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
16596 TREE_LIST. We can handle it exactly the same as an array section
16597 (purpose, value, and a chain), even though the nomenclature
16598 (low_bound, length, etc) is different. */
16600 {
16601 tree low_bound
16616 }
16619 /* Undo convert_from_reference tsubst_expr could have called. */
16625 }
16627 /* Like tsubst_copy, but specifically for OpenMP clauses. */
16629 static tree
16632 {
16638 {
16644 {
16647 {
16653 }
16654 /* FALLTHRU */
16707 {
16710 {
16717 }
16718 else
16720 }
16739 {
16742 }
16747 else
16750 in_decl,
16778 }
16781 {
16796 /* tsubst_expr on SCOPE_REF results in returning
16797 finish_non_static_data_member result. Undo that here. */
16801 {
16806 {
16810 CASE_CONVERT:
16819 /* FALLTHRU */
16823 }
16824 }
16830 {
16833 {
16836 }
16837 }
16841 }
16842 }
16846 {
16851 {
16854 }
16855 }
16857 }
16859 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
16861 static tree
16863 tree in_decl)
16864 {
16865 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
16885 {
16888 else
16889 {
16893 }
16894 }
16899 #undef RECUR
16900 }
16902 /* Used to temporarily communicate the list of #pragma omp parallel
16903 clauses to #pragma omp for instantiation if they are combined
16904 together. */
16911 /* Substitute one OMP_FOR iterator. */
16913 static bool
16918 {
16919 #define RECUR(NODE) \
16920 tsubst_expr ((NODE), args, complain, in_decl, \
16921 integral_constant_expression_p)
16933 {
16936 {
16941 {
16951 else
16953 {
16955 {
16961 }
16964 }
16965 }
16966 }
16970 }
16972 {
16973 /* We need to jump through some hoops to handle declarations in the
16974 init-statement, since we might need to handle auto deduction,
16975 but we need to keep control of initialization. */
16979 }
16980 else
16981 {
16983 {
16986 {
16990 {
16994 CASE_CONVERT:
17002 {
17005 }
17006 /* FALLTHRU */
17010 }
17011 }
17012 }
17013 else
17015 }
17019 {
17025 NULL_TREE);
17026 else
17028 }
17031 {
17038 {
17043 }
17046 }
17056 {
17058 {
17059 /* Declare the variable, but don't let that initialize it. */
17064 }
17067 {
17071 {
17076 }
17077 else
17081 }
17087 }
17090 {
17091 /* Declare and initialize the variable. */
17094 }
17096 {
17101 {
17103 {
17109 {
17112 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
17117 }
17120 {
17122 decl);
17124 }
17127 {
17129 decl);
17131 }
17132 else
17134 }
17137 }
17139 {
17142 ? OMP_CLAUSE_LASTPRIVATE
17147 {
17150 }
17151 }
17152 }
17155 {
17159 }
17160 else
17164 {
17175 {
17183 }
17184 else
17190 {
17196 }
17200 {
17208 }
17209 else
17215 }
17224 #undef RECUR
17225 }
17227 /* Helper function of tsubst_expr, find OMP_TEAMS inside
17228 of OMP_TARGET's body. */
17230 static tree
17232 {
17235 {
17244 }
17246 }
17248 /* Helper function for tsubst_expr. For decomposition declaration
17249 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
17250 also the corresponding decls representing the identifiers
17251 of the decomposition declaration. Return DECL if successful
17252 or error_mark_node otherwise, set *FIRST to the first decl
17253 in the list chained through DECL_CHAIN and *CNT to the number
17254 of such decls. */
17256 static tree
17260 {
17265 decl2
17270 {
17272 {
17275 }
17287 else
17288 {
17292 }
17299 {
17302 }
17303 else
17305 }
17308 }
17310 /* Return the proper local_specialization for init-capture pack DECL. */
17312 static tree
17314 {
17315 /* We handle normal pack captures by forwarding to the specialization of the
17316 captured parameter. We can't do that for pack init-captures; we need them
17317 to have their own local_specialization. We created the individual
17318 VAR_DECLs (if any) under build_capture_proxy, and we need to collect them
17319 when we process the DECL_EXPR for the pack init-capture in the template.
17320 So, how do we find them? We don't know the capture proxy pack when
17321 building the individual resulting proxies, and we don't know the
17322 individual proxies when instantiating the pack. What we have in common is
17323 the FIELD_DECL.
17325 So...when we instantiate the FIELD_DECL, we stick the result in
17326 local_specializations. Then at the DECL_EXPR we look up that result, see
17327 how many elements it has, synthesize the names, and look them up. */
17341 {
17346 }
17348 {
17353 else
17355 }
17357 }
17359 /* Like tsubst_copy for expressions, etc. but also does semantic
17360 processing. */
17362 tree
17365 {
17366 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
17367 #define RECUR(NODE) \
17368 tsubst_expr ((NODE), args, complain, in_decl, \
17369 integral_constant_expression_p)
17372 tree r;
17373 location_t loc;
17385 {
17387 {
17388 tree_stmt_iterator i;
17392 }
17407 else
17416 {
17418 tree init;
17424 {
17430 }
17433 {
17434 /* We're in tsubst_lambda_expr, we've already inserted a new
17435 capture proxy, so look it up and register it. */
17436 tree inst;
17438 {
17443 }
17445 {
17446 inst = (retrieve_local_specialization
17449 }
17450 else
17455 }
17462 /* Don't copy the old closure; we'll create a new one in
17463 tsubst_lambda_expr. */
17465 else
17466 {
17468 /* The following tsubst call will clear the DECL_TEMPLATE_INFO
17469 for local variables, so save if DECL was declared constinit. */
17470 const bool constinit_p
17477 {
17478 /* By marking the declaration as instantiated, we avoid
17479 trying to instantiate it. Since instantiate_decl can't
17480 handle local variables, and since we've already done
17481 all that needs to be done, that's the right thing to
17482 do. */
17487 /* Anonymous aggregates are a special case. */
17490 {
17493 {
17497 }
17499 }
17505 {
17510 }
17511 else
17512 {
17528 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
17539 }
17540 }
17541 }
17544 }
17554 {
17558 }
17563 {
17564 /* Construct another range_for, if this is not a final
17565 substitution (for inside inside a generic lambda of a
17566 template). Otherwise convert to a regular for. */
17568 stmt = (processing_template_decl
17585 {
17591 }
17592 else
17593 {
17599 }
17605 }
17612 {
17616 }
17622 {
17626 }
17641 {
17642 /* We're partially instantiating a generic lambda, but the condition
17643 of the constexpr if is still dependent. Don't substitute into the
17644 branches now, just remember the template arguments. */
17652 }
17655 else
17656 {
17664 }
17670 {
17680 }
17688 else
17696 else
17717 {
17723 {
17728 }
17729 }
17733 {
17735 tree label;
17742 }
17748 /* Computed goto's must be tsubst'd into. On the other hand,
17749 non-computed gotos must not be; the identifier in question
17750 will have no binding. */
17752 else
17758 {
17775 }
17780 {
17785 }
17786 else
17787 {
17792 else
17799 else
17805 else
17807 }
17811 {
17815 {
17817 /* Prevent instantiate_decl from trying to instantiate
17818 this variable. We've already done all that needs to be
17819 done. */
17822 }
17827 }
17833 {
17834 /* Local classes are not independent templates; they are
17835 instantiated along with their containing function. And this
17836 way we don't have to deal with pushing out of one local class
17837 to instantiate a member of another local class. */
17838 /* Closures are handled by the LAMBDA_EXPR. */
17848 }
17852 {
17853 tree condition;
17856 condition =
17858 args,
17867 }
17873 in_decl);
17895 {
17902 }
17918 {
17932 in_decl);
17934 {
17941 }
17952 any_range_for
17956 integral_constant_expression_p);
17960 {
17969 }
17970 else
17975 else
17982 else
17983 {
17991 }
17994 t));
17996 }
18001 /* FALLTHRU */
18010 in_decl);
18012 {
18017 }
18018 else
18019 {
18023 }
18035 {
18038 {
18043 }
18044 else
18045 {
18049 }
18051 }
18052 else
18054 OMP_CLAUSE_DEPEND_SOURCE,
18063 in_decl);
18074 {
18077 {
18078 /* For combined target teams, ensure the num_teams and
18079 thread_limit clause expressions are evaluated on the host,
18080 before entering the target construct. */
18081 tree c;
18087 {
18096 OMP_CLAUSE_FIRSTPRIVATE);
18100 }
18101 }
18102 }
18165 {
18170 {
18173 }
18179 }
18180 else
18181 {
18188 {
18191 }
18194 {
18199 {
18202 }
18208 }
18209 else
18210 {
18214 }
18217 }
18221 {
18227 {
18231 {
18236 }
18240 }
18241 else
18242 {
18247 }
18248 }
18252 {
18256 }
18269 /* If the first operand was a statement, we're done with it. */
18273 complain));
18290 integral_constant_expression_p));
18291 }
18294 out:
18297 #undef RECUR
18298 #undef RETURN
18299 }
18301 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
18302 function. For description of the body see comment above
18303 cp_parser_omp_declare_reduction_exprs. */
18305 static void
18307 {
18313 tree_stmt_iterator tsi;
18324 {
18343 }
18345 {
18365 }
18366 }
18368 /* T is a postfix-expression that is not being used in a function
18369 call. Return the substituted version of T. */
18371 static tree
18373 tsubst_flags_t complain,
18374 tree in_decl)
18375 {
18379 else
18385 }
18387 /* Subroutine of tsubst_lambda_expr: add the FIELD/INIT capture pair to the
18388 LAMBDA_EXPR_CAPTURE_LIST passed in LIST. Do deduction for a previously
18389 dependent init-capture. */
18391 static void
18393 tsubst_flags_t complain)
18394 {
18396 {
18399 {
18403 }
18410 }
18412 }
18414 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
18415 instantiation context. Instantiating a pack expansion containing a lambda
18416 might result in multiple lambdas all based on the same lambda in the
18417 template. */
18419 tree
18421 {
18435 /* A lambda in a default argument outside a class gets no
18436 LAMBDA_EXPR_EXTRA_SCOPE, as specified by the ABI. But
18437 tsubst_default_argument calls start_lambda_scope, so we need to
18438 specifically ignore it here, and use the global scope. */
18440 else
18450 {
18457 {
18458 /* Remember these for when we've pushed local_specializations. */
18461 }
18469 else
18474 {
18482 complain);
18483 }
18484 else
18485 {
18487 complain);
18491 }
18492 }
18498 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
18516 else
18517 {
18518 /* The body of a lambda-expression is not a subexpression of the
18519 enclosing expression. Parms are to have DECL_CHAIN tsubsted,
18520 which would be skipped if cp_unevaluated_operand. */
18521 cp_evaluated ev;
18523 /* Fix the type of 'this'. */
18529 {
18533 }
18534 else
18535 {
18539 }
18541 /* Let finish_function set this. */
18547 else
18548 /* Still increment function_depth so that we don't GC in the
18549 middle of an expression. */
18556 /* Now record them for lookup_init_capture_pack. */
18559 {
18563 }
18569 {
18570 /* We might not partially instantiate some parts of the function, so
18571 copy these flags from the original template. */
18577 }
18579 /* [temp.deduct] A lambda-expression appearing in a function type or a
18580 template parameter is not considered part of the immediate context for
18581 the purposes of template argument deduction. */
18591 else
18594 /* The capture list was built up in reverse order; fix that now. */
18601 }
18608 }
18610 /* Like tsubst but deals with expressions and performs semantic
18611 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
18613 tree
18615 tree args,
18616 tsubst_flags_t complain,
18617 tree in_decl,
18620 {
18621 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
18622 #define RECUR(NODE) \
18623 tsubst_copy_and_build (NODE, args, complain, in_decl, \
18625 integral_constant_expression_p)
18628 location_t loc;
18637 /* N3276 decltype magic only applies to calls at the top level or on the
18638 right side of a comma. */
18643 {
18646 /* Fall through. */
18648 {
18649 tree decl;
18650 cp_id_kind idk;
18655 {
18658 }
18660 /* Look up the name. */
18663 /* By convention, expressions use ERROR_MARK_NODE to indicate
18664 failure, not NULL_TREE. */
18670 integral_constant_expression_p,
18678 input_location);
18682 {
18686 }
18688 }
18691 {
18692 tree object;
18702 {
18707 }
18710 {
18717 /* If we built a function concept check, return the underlying
18718 template-id. So we can evaluate it as a function call. */
18722 /* Evaluate the concept, if needed. */
18729 }
18735 {
18738 }
18739 else
18746 else
18748 }
18751 {
18755 {
18756 /* A type conversion to reference type will be enclosed in
18757 such an indirect ref, but the substitution of the cast
18758 will have also added such an indirect ref. */
18760 }
18761 else
18769 }
18772 {
18776 }
18779 {
18783 {
18788 }
18790 /* We'll pass this to convert_nontype_argument again, we don't need
18791 to actually perform any conversion here. */
18799 flags));
18800 }
18803 {
18809 }
18816 {
18817 tree type;
18823 {
18828 }
18835 {
18853 }
18856 }
18889 else
18891 in_decl);
18924 {
18931 tree r = build_x_binary_op
18933 op0,
18935 ? ERROR_MARK
18937 op1,
18939 ? ERROR_MARK
18947 }
18950 {
18954 }
18970 /* Fall through */
18973 {
18974 tree r;
18982 {
18983 /* When there are no ARGS, we are trying to evaluate a
18984 non-dependent expression from the parser. Trying to do
18985 the substitutions may not work. */
18988 }
18989 else
18990 {
18995 else
18998 /*integral_constant_expression_p=*/
19002 }
19006 else
19010 {
19012 {
19014 {
19018 }
19019 else
19023 }
19025 }
19027 }
19030 {
19040 }
19056 {
19060 tree r = build_x_modify_expr
19063 /* TREE_NO_WARNING must be set if either the expression was
19064 parenthesized or it uses an operator such as >>= rather
19065 than plain assignment. In the former case, it was already
19066 set and must be copied. In the latter case,
19067 build_x_modify_expr sets it and it must not be reset
19068 here. */
19073 }
19078 /* Remember that there was a reference to this entity. */
19085 {
19090 tree ret;
19094 else
19095 {
19099 }
19101 /* If there was an initializer in the original tree, but it
19102 instantiated to an empty list, then we should pass a
19103 non-NULL empty vector to tell build_new that it was an
19104 empty initializer() rather than no initializer. This can
19105 only happen when the initializer is a pack expansion whose
19106 parameter packs are of length zero. */
19109 else
19110 {
19114 else
19115 {
19118 }
19119 }
19121 /* Avoid passing an enclosing decl to valid_array_size_p. */
19128 complain);
19136 }
19139 {
19145 complain));
19146 }
19149 {
19153 integral_constant_expression_p);
19155 op0,
19158 }
19161 {
19162 tree function;
19166 tree ret;
19169 /* Internal function with no arguments. */
19173 /* When we parsed the expression, we determined whether or
19174 not Koenig lookup should be performed. */
19177 {
19180 }
19182 {
19187 }
19189 {
19190 /* Do nothing; calling tsubst_copy_and_build on an identifier
19191 would incorrectly perform unqualified lookup again.
19193 Note that we can also have an IDENTIFIER_NODE if the earlier
19194 unqualified lookup found a member function; in that case
19195 koenig_p will be false and we do want to do the lookup
19196 again to find the instantiated member function.
19198 FIXME but doing that causes c++/15272, so we need to stop
19199 using IDENTIFIER_NODE in that situation. */
19201 }
19202 else
19203 {
19205 {
19211 }
19212 else
19217 /* Avoid error about taking the address of a constructor. */
19221 in_decl,
19223 integral_constant_expression_p);
19227 }
19230 releasing_vec call_args;
19232 {
19237 else
19238 {
19239 /* Expand the pack expansion and push each entry onto
19240 CALL_ARGS. */
19243 {
19248 {
19253 }
19254 }
19255 else
19256 {
19257 /* A partial substitution. Add one entry. */
19259 }
19260 }
19261 }
19263 /* Stripped-down processing for a call in a thunk. Specifically, in
19264 the thunk template for a generic lambda. */
19266 {
19267 /* Now that we've expanded any packs, the number of call args
19268 might be different. */
19272 {
19279 }
19280 /* We aren't going to do normal overload resolution, so force the
19281 template-id to resolve. */
19284 {
19285 /* In a thunk, pass through args directly, without any
19286 conversions. */
19291 }
19293 {
19294 /* If there are no other args, just push 'this'. */
19297 else
19298 {
19299 /* Otherwise, shift the other args over to make room. */
19305 }
19306 }
19309 /* The thunk location is not interesting. */
19316 }
19318 /* We do not perform argument-dependent lookup if normal
19319 lookup finds a non-function, in accordance with the
19320 expected resolution of DR 218. */
19323 /* If lookup found a member function, the Koenig lookup is
19324 not appropriate, even if an unqualified-name was used
19325 to denote the function. */
19328 /* Only do this when substitution turns a dependent call
19329 into a non-dependent call. */
19337 {
19339 {
19340 /* For backwards compatibility and good diagnostics, try
19341 the unqualified lookup again if we aren't in SFINAE
19342 context. */
19343 tree unq = (tsubst_copy_and_build
19345 integral_constant_expression_p));
19350 {
19351 /* In a lambda fn, we have to be careful to not
19352 introduce new this captures. Legacy code can't
19353 be using lambdas anyway, so it's ok to be
19354 stricter. */
19359 "and no declarations were found by "
19360 "argument-dependent lookup at the point "
19367 else
19371 {
19382 {
19385 "declarations in dependent base %qT are "
19391 else
19395 }
19396 else
19398 "%qD declared here, later in the "
19402 }
19405 }
19406 }
19408 {
19412 }
19413 }
19415 /* Remember that there was a reference to this entity. */
19421 /* Put back tf_decltype for the actual call. */
19426 {
19430 {
19432 "wrong number of arguments to "
19435 }
19436 else
19444 {
19446 "wrong number of arguments to "
19450 }
19454 complain);
19460 /* Unsupported internal function with arguments. */
19462 }
19467 complain);
19469 {
19484 complain);
19485 else
19486 ret = (build_new_method_call
19491 complain));
19492 }
19494 {
19495 /* FUNCTION is a template-id referring to a concept definition. */
19500 /* Calls to standard and variable concepts should have been
19501 previously diagnosed. */
19504 /* Ensure the result is wrapped as a call expression. */
19507 /* Possibly evaluate the check if it is non-dependent. */
19511 }
19512 else
19515 koenig_p,
19516 complain);
19519 {
19524 {
19529 }
19530 }
19533 }
19536 {
19543 {
19545 {
19550 }
19551 else
19552 {
19557 }
19559 }
19560 else
19561 {
19564 }
19569 }
19572 {
19577 input_location));
19578 }
19581 {
19589 {
19590 /* We have pack expansions, so expand those and
19591 create a new list out of it. */
19594 tree chain;
19597 /* Expand the argument expressions. */
19605 /* Build the rest of the list. */
19610 /* Determine the number of arguments. */
19612 {
19615 }
19618 else
19619 {
19620 /* Since we only performed a partial substitution into
19621 the argument pack, we only RETURN (a single list
19622 node. */
19629 }
19631 /* Convert the argument vectors into a TREE_LIST */
19634 {
19635 /* Grab the Ith values. */
19636 i--;
19639 value
19643 /* Build the list (backwards). */
19645 }
19648 }
19664 }
19667 {
19668 tree object;
19669 tree object_type;
19670 tree member;
19671 tree r;
19675 /* Remember that there was a reference to this entity. */
19686 else
19692 {
19697 }
19701 {
19703 {
19708 {
19711 }
19713 {
19718 }
19719 }
19720 }
19723 {
19724 /* Lookup the template functions now that we know what the
19725 scope is. */
19733 {
19736 args);
19737 member = (adjust_result_of_qualified_name_lookup
19739 object_type));
19740 }
19741 else
19742 {
19744 input_location);
19746 }
19747 }
19751 {
19753 {
19757 else
19760 }
19762 }
19766 complain);
19770 }
19777 {
19785 tree r;
19790 /* We do not want to process the index of aggregate
19791 initializers as they are identifier nodes which will be
19792 looked up by digest_init. */
19796 {
19799 }
19804 {
19806 /* An identifier index is looked up in the type
19807 being initialized, not the current scope. */
19812 {
19813 /* Substitute into the pack expansion. */
19815 in_decl);
19819 ;
19821 /* Just move the argument into place. */
19823 else
19824 {
19825 /* Update the length of the final CONSTRUCTOR
19826 arguments vector, and note that we will need to
19827 copy.*/
19830 }
19831 }
19832 else
19834 }
19837 {
19842 {
19844 {
19849 }
19850 else
19852 }
19853 }
19861 {
19866 }
19870 }
19873 {
19876 {
19879 }
19880 else
19881 {
19884 }
19885 }
19890 /* Fall through */
19893 {
19895 /* ??? We're doing a subset of finish_id_expression here. */
19897 /* Replace an evaluated use of the thread_local variable with
19898 a call to its wrapper. */
19904 /* If the original type was a reference, we'll be wrapped in
19905 the appropriate INDIRECT_REF. */
19908 }
19911 {
19915 }
19918 {
19919 tree object_ptr
19926 }
19933 {
19945 }
19948 {
19954 integral_constant_expression_p);
19958 /* If the resulting list of expression statement is empty,
19959 fold it further into void_node. */
19964 }
19967 {
19969 {
19970 /* We don't have a full set of template arguments yet; don't touch
19971 the lambda at all. */
19974 }
19978 }
19981 /* We can get here for a constant initializer of non-dependent type.
19982 FIXME stop folding in cp_parser_initializer_clause. */
19983 {
19985 complain);
19987 }
19991 integral_constant_expression_p));
19997 {
20002 complain));
20003 }
20009 /* No need to substitute further, a RANGE_EXPR will always be built
20010 with constant operands. */
20016 /* We need to do this here as well as in tsubst_copy so we get the
20017 other tsubst_copy_and_build semantics for a PARM_DECL operand. */
20020 /* fallthrough. */
20023 /* Handle Objective-C++ constructs, if appropriate. */
20024 {
20025 tree subst
20030 }
20032 }
20034 #undef RECUR
20035 #undef RETURN
20036 out:
20039 }
20041 /* Verify that the instantiated ARGS are valid. For type arguments,
20042 make sure that the type's linkage is ok. For non-type arguments,
20043 make sure they are constants if they are integral or enumerations.
20044 Emit an error under control of COMPLAIN, and return TRUE on error. */
20046 static bool
20048 {
20052 {
20062 }
20064 {
20065 /* [basic.link]: A name with no linkage (notably, the name
20066 of a class or enumeration declared in a local scope)
20067 shall not be used to declare an entity with linkage.
20068 This implies that names with no linkage cannot be used as
20069 template arguments
20071 DR 757 relaxes this restriction for C++0x. */
20076 {
20077 /* DR 488 makes use of a type with no linkage cause
20078 type deduction to fail. */
20080 {
20083 else
20086 }
20088 }
20089 /* In order to avoid all sorts of complications, we do not
20090 allow variably-modified types as template arguments. */
20092 {
20096 }
20097 }
20098 /* Class template and alias template arguments should be OK. */
20100 ;
20101 /* A non-type argument of integral or enumerated type must be a
20102 constant. */
20107 {
20111 }
20113 }
20115 static bool
20117 {
20122 {
20125 }
20129 }
20131 /* We're out of SFINAE context now, so generate diagnostics for the access
20132 errors we saw earlier when instantiating D from TMPL and ARGS. */
20134 static void
20136 {
20148 }
20150 /* Instantiate the indicated variable, function, or alias template TMPL with
20151 the template arguments in TARG_PTR. */
20153 static tree
20155 {
20157 tree fndecl;
20158 tree gen_tmpl;
20159 tree spec;
20167 /* If this function is a clone, handle it specially. */
20169 {
20170 tree spec;
20171 tree clone;
20173 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
20174 DECL_CLONED_FUNCTION. */
20180 /* Look for the clone. */
20184 /* We should always have found the clone by now. */
20187 }
20192 /* Check to see if we already have this specialization. */
20196 /* targ_ptr only has the innermost template args, so add the outer ones
20197 from tmpl, which could be either a partial instantiation or gen_tmpl (in
20198 the case of a non-dependent call within a template definition). */
20199 targ_ptr = (add_outermost_template_args
20201 targ_ptr));
20203 /* It would be nice to avoid hashing here and then again in tsubst_decl,
20204 but it doesn't seem to be on the hot path. */
20213 {
20215 {
20219 }
20221 }
20224 complain))
20227 /* We are building a FUNCTION_DECL, during which the access of its
20228 parameters and return types have to be checked. However this
20229 FUNCTION_DECL which is the desired context for access checking
20230 is not built yet. We solve this chicken-and-egg problem by
20231 deferring all checks until we have the FUNCTION_DECL. */
20234 /* Instantiation of the function happens in the context of the function
20235 template, not the context of the overload resolution we're doing. */
20237 /* If there are dependent arguments, e.g. because we're doing partial
20238 ordering, make sure processing_template_decl stays set. */
20242 {
20246 }
20252 {
20253 /* We need to determine if we're using a partial or explicit
20254 specialization now, because the type of the variable could be
20255 different. */
20261 {
20266 }
20267 }
20269 /* Substitute template parameters to obtain the specialization. */
20277 {
20280 }
20282 /* The DECL_TI_TEMPLATE should always be the immediate parent
20283 template, not the most general template. */
20287 /* Now we know the specialization, compute access previously
20288 deferred. Do no access control for inheriting constructors,
20289 as we already checked access for the inherited constructor. */
20292 {
20297 }
20300 /* If we've just instantiated the main entry point for a function,
20301 instantiate all the alternate entry points as well. We do this
20302 by cloning the instantiation of the main entry point, not by
20303 instantiating the template clones. */
20309 {
20311 {
20312 /* Remember to reinstantiate when we're out of SFINAE so the user
20313 can see the errors. */
20315 }
20317 }
20319 }
20321 /* Wrapper for instantiate_template_1. */
20323 tree
20325 {
20326 tree ret;
20331 }
20333 /* Instantiate the alias template TMPL with ARGS. Also push a template
20334 instantiation level, which instantiate_template doesn't do because
20335 functions and variables have sufficient context established by the
20336 callers. */
20338 static tree
20340 {
20346 args =
20356 }
20358 /* PARM is a template parameter pack for FN. Returns true iff
20359 PARM is used in a deducible way in the argument list of FN. */
20361 static bool
20363 {
20366 {
20368 tree packs;
20374 {
20375 /* The template parameter pack is used in a function parameter
20376 pack. If this is the end of the parameter list, the
20377 template parameter pack is deducible. */
20380 else
20381 /* Otherwise, not. Well, it could be deduced from
20382 a non-pack parameter, but doing so would end up with
20383 a deduction mismatch, so don't bother. */
20385 }
20386 }
20387 /* The template parameter pack isn't used in any function parameter
20388 packs, but it might be used deeper, e.g. tuple<Args...>. */
20390 }
20392 /* Subroutine of fn_type_unification: check non-dependent parms for
20393 convertibility. */
20395 static int
20399 {
20400 /* Non-constructor methods need to leave a conversion for 'this', which
20401 isn't included in nargs here. */
20407 {
20413 /* For a function parameter pack that occurs at the end of the
20414 parameter-declaration-list, the type A of each remaining
20415 argument of the call is compared with the type P of the
20416 declarator-id of the function parameter pack. */
20422 /* For a function parameter pack that does not occur at the
20423 end of the parameter-declaration-list, the type of the
20424 parameter pack is a non-deduced context. */
20428 {
20436 }
20439 }
20442 }
20444 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
20445 NARGS elements of the arguments that are being used when calling
20446 it. TARGS is a vector into which the deduced template arguments
20447 are placed.
20449 Returns either a FUNCTION_DECL for the matching specialization of FN or
20450 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
20451 true, diagnostics will be printed to explain why it failed.
20453 If FN is a conversion operator, or we are trying to produce a specific
20454 specialization, RETURN_TYPE is the return type desired.
20456 The EXPLICIT_TARGS are explicit template arguments provided via a
20457 template-id.
20459 The parameter STRICT is one of:
20461 DEDUCE_CALL:
20462 We are deducing arguments for a function call, as in
20463 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
20464 deducing arguments for a call to the result of a conversion
20465 function template, as in [over.call.object].
20467 DEDUCE_CONV:
20468 We are deducing arguments for a conversion function, as in
20469 [temp.deduct.conv].
20471 DEDUCE_EXACT:
20472 We are deducing arguments when doing an explicit instantiation
20473 as in [temp.explicit], when determining an explicit specialization
20474 as in [temp.expl.spec], or when taking the address of a function
20475 template, as in [temp.deduct.funcaddr]. */
20477 tree
20479 tree explicit_targs,
20480 tree targs,
20483 tree return_type,
20484 unification_kind_t strict,
20489 {
20490 tree parms;
20491 tree fntype;
20496 /* type_unification_real will pass back any access checks from default
20497 template argument substitution. */
20499 /* We don't have all the template args yet. */
20512 full_targs = (add_outermost_template_args
20514 targs));
20519 /* In C++0x, it's possible to have a function template whose type depends
20520 on itself recursively. This is most obvious with decltype, but can also
20521 occur with enumeration scope (c++/48969). So we need to catch infinite
20522 recursion and reject the substitution at deduction time; this function
20523 will return error_mark_node for any repeated substitution.
20525 This also catches excessive recursion such as when f<N> depends on
20526 f<N-1> across all integers, and returns error_mark_node for all the
20527 substitutions back up to the initial one.
20529 This is, of course, not reentrant. */
20538 {
20539 /* [temp.deduct]
20541 The specified template arguments must match the template
20542 parameters in kind (i.e., type, nontype, template), and there
20543 must not be more arguments than there are parameters;
20544 otherwise type deduction fails.
20546 Nontype arguments must match the types of the corresponding
20547 nontype template parameters, or must be convertible to the
20548 types of the corresponding nontype parameters as specified in
20549 _temp.arg.nontype_, otherwise type deduction fails.
20551 All references in the function type of the function template
20552 to the corresponding template parameters are replaced by the
20553 specified template argument values. If a substitution in a
20554 template parameter or in the function type of the function
20555 template results in an invalid type, type deduction fails. */
20566 explicit_targs);
20568 /* Adjust any explicit template arguments before entering the
20569 substitution context. */
20570 explicit_targs
20578 /* Substitute the explicit args into the function type. This is
20579 necessary so that, for instance, explicitly declared function
20580 arguments can match null pointed constants. If we were given
20581 an incomplete set of explicit args, we must not do semantic
20582 processing during substitution as we could create partial
20583 instantiations. */
20585 {
20590 /* Dig out the actual parm. */
20593 {
20596 }
20598 {
20601 }
20604 /* No explicit argument for this template parameter. */
20607 {
20608 /* Mark the argument pack as "incomplete". We could
20609 still deduce more arguments during unification.
20610 We remove this mark in type_unification_real. */
20615 /* We have some incomplete argument packs. */
20617 }
20618 }
20621 {
20623 {
20626 }
20629 /* Ignore any access checks; we'll see them again in
20630 instantiate_template and they might have the wrong
20631 access path at this point. */
20642 }
20644 /* Place the explicitly specified arguments in TARGS. */
20650 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
20652 }
20655 {
20661 }
20666 /* Never do unification on the 'this' parameter. */
20670 {
20671 /* We're deducing for a call to the result of a template conversion
20672 function. The parms we really want are in return_type. */
20676 }
20678 {
20680 }
20682 /* We allow incomplete unification without an error message here
20683 because the standard doesn't seem to explicitly prohibit it. Our
20684 callers must be ready to deal with unification failures in any
20685 event. */
20687 /* If we aren't explaining yet, push tinst context so we can see where
20688 any errors (e.g. from class instantiations triggered by instantiation
20689 of default template arguments) come from. If we are explaining, this
20690 context is redundant. */
20692 {
20695 }
20705 /* Now that we have bindings for all of the template arguments,
20706 ensure that the arguments deduced for the template template
20707 parameters have compatible template parameter lists. We cannot
20708 check this property before we have deduced all template
20709 arguments, because the template parameter types of a template
20710 template parameter might depend on prior template parameters
20711 deduced after the template template parameter. The following
20712 ill-formed example illustrates this issue:
20714 template<typename T, template<T> class C> void f(C<5>, T);
20716 template<int N> struct X {};
20718 void g() {
20719 f(X<5>(), 5l); // error: template argument deduction fails
20720 }
20722 The template parameter list of 'C' depends on the template type
20723 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
20724 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
20725 time that we deduce 'C'. */
20728 {
20731 }
20733 /* DR 1391: All parameters have args, now check non-dependent parms for
20734 convertibility. */
20739 deduced:
20740 /* All is well so far. Now, check:
20742 [temp.deduct]
20744 When all template arguments have been deduced, all uses of
20745 template parameters in nondeduced contexts are replaced with
20746 the corresponding deduced argument values. If the
20747 substitution results in an invalid type, as described above,
20748 type deduction fails. */
20750 {
20753 }
20755 /* Also collect access checks from the instantiation. */
20768 /* Now perform any access checks encountered during substitution. */
20775 /* If we're looking for an exact match, check that what we got
20776 is indeed an exact match. It might not be if some template
20777 parameters are used in non-deduced contexts. But don't check
20778 for an exact match if we have dependent template arguments;
20779 in that case we're doing partial ordering, and we already know
20780 that we have two candidates that will provide the actual type. */
20782 {
20786 tree sarg
20792 {
20796 }
20797 }
20799 /* After doing deduction with the inherited constructor, actually return an
20800 instantiation of the inheriting constructor. */
20806 fail:
20809 {
20811 /* Reset once we're all the way out. */
20813 }
20816 }
20818 /* Adjust types before performing type deduction, as described in
20819 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
20820 sections are symmetric. PARM is the type of a function parameter
20821 or the return type of the conversion function. ARG is the type of
20822 the argument passed to the call, or the type of the value
20823 initialized with the result of the conversion function.
20824 ARG_EXPR is the original argument expression, which may be null. */
20826 static int
20830 tree arg_expr)
20831 {
20835 {
20840 /* Swap PARM and ARG throughout the remainder of this
20841 function; the handling is precisely symmetric since PARM
20842 will initialize ARG rather than vice versa. */
20847 /* Core issue #873: Do the DR606 thing (see below) for these cases,
20848 too, but here handle it by stripping the reference from PARM
20849 rather than by adding it to ARG. */
20857 /* Nothing else to do in this case. */
20862 }
20865 {
20866 /* [temp.deduct.call]
20868 If P is not a reference type:
20870 --If A is an array type, the pointer type produced by the
20871 array-to-pointer standard conversion (_conv.array_) is
20872 used in place of A for type deduction; otherwise,
20874 --If A is a function type, the pointer type produced by
20875 the function-to-pointer standard conversion
20876 (_conv.func_) is used in place of A for type deduction;
20877 otherwise,
20879 --If A is a cv-qualified type, the top level
20880 cv-qualifiers of A's type are ignored for type
20881 deduction. */
20886 else
20888 }
20890 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
20891 reference to a cv-unqualified template parameter that does not represent a
20892 template parameter of a class template (during class template argument
20893 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
20894 an lvalue, the type "lvalue reference to A" is used in place of A for type
20895 deduction. */
20902 /* try_one_overload doesn't provide an arg_expr, but
20903 functions are always lvalues. */
20907 /* [temp.deduct.call]
20909 If P is a cv-qualified type, the top level cv-qualifiers
20910 of P's type are ignored for type deduction. If P is a
20911 reference type, the type referred to by P is used for
20912 type deduction. */
20915 {
20918 }
20920 /* DR 322. For conversion deduction, remove a reference type on parm
20921 too (which has been swapped into ARG). */
20926 }
20928 /* Subroutine of fn_type_unification. PARM is a function parameter of a
20929 template which doesn't contain any deducible template parameters; check if
20930 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
20931 unify_one_argument. */
20933 static int
20937 {
20938 tree type;
20942 else
20950 {
20953 }
20955 {
20959 /* Avoid recalculating this in add_function_candidate. */
20960 ok = (*conv_p
20962 else
20966 }
20970 else
20972 }
20976 /* Returns true iff the expression EXPR is one from which a template
20977 argument can be deduced. In other words, if it's an undecorated
20978 use of a template non-type parameter. */
20980 static bool
20982 {
20983 /* Strip implicit conversions. */
20987 }
20989 /* Returns true iff the array domain DOMAIN uses a template parameter in a
20990 deducible way; that is, if it has a max value of <PARM> - 1. */
20992 static bool
20994 {
21003 }
21005 /* Returns true iff the template arguments ARGS use a template parameter
21006 in a deducible way. */
21008 static bool
21010 {
21012 {
21017 else
21018 {
21025 else
21027 }
21030 }
21032 }
21034 /* Returns true iff TYPE contains any deducible references to template
21035 parameters, as per 14.8.2.5. */
21037 static bool
21039 {
21043 /* T
21044 cv-list T
21045 TT<T>
21046 TT<i>
21047 TT<> */
21052 /* T*
21053 T&
21054 T&& */
21058 /* T[integer-constant ]
21059 type [i] */
21064 /* T type ::*
21065 type T::*
21066 T T::*
21067 T (type ::*)()
21068 type (T::*)()
21069 type (type ::*)(T)
21070 type (T::*)(T)
21071 T (type ::*)(T)
21072 T (T::*)()
21073 T (T::*)(T) */
21076 || (uses_deducible_template_parms
21079 /* template-name <T> (where template-name refers to a class template)
21080 template-name <i> (where template-name refers to a class template) */
21087 /* type (T)
21088 T()
21089 T(T) */
21091 {
21100 }
21103 }
21105 /* Subroutine of type_unification_real and unify_pack_expansion to
21106 handle unification of a single P/A pair. Parameters are as
21107 for those functions. */
21109 static int
21113 {
21120 /* We can't deduce anything from this, but we might get all the
21121 template args from other function args. */
21124 /* Implicit conversions (Clause 4) will be performed on a function
21125 argument to convert it to the type of the corresponding function
21126 parameter if the parameter type contains no template-parameters that
21127 participate in template argument deduction. */
21130 /* For function parameters with no deducible template parameters,
21131 just return. We'll check non-dependent conversions later. */
21135 {
21137 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
21138 | UNIFY_ALLOW_MORE_CV_QUAL
21152 }
21154 /* We only do these transformations if this is the top-level
21155 parameter_type_list in a call or declaration matching; in other
21156 situations (nested function declarators, template argument lists) we
21157 won't be comparing a type to an expression, and we don't do any type
21158 adjustments. */
21160 {
21162 {
21165 {
21166 /* [temp.deduct.type] A template-argument can be
21167 deduced from a pointer to function or pointer
21168 to member function argument if the set of
21169 overloaded functions does not contain function
21170 templates and at most one of a set of
21171 overloaded functions provides a unique
21172 match. */
21176 /* If a unique match was not found, this is a
21177 non-deduced context, so we still succeed. */
21179 }
21185 }
21187 arg_strict |=
21189 }
21190 else
21195 /* For deduction from an init-list we need the actual list. */
21199 }
21201 /* for_each_template_parm callback that always returns 0. */
21203 static int
21205 {
21207 }
21209 /* for_each_template_parm any_fn callback to handle deduction of a template
21210 type argument from the type of an array bound. */
21212 static int
21214 {
21222 {
21228 }
21230 /* Keep walking. */
21232 }
21234 /* Try to deduce any not-yet-deduced template type arguments from the type of
21235 an array bound. This is handled separately from unify because 14.8.2.5 says
21236 "The type of a type parameter is only deduced from an array bound if it is
21237 not otherwise deduced." */
21239 static void
21241 {
21246 }
21248 /* Most parms like fn_type_unification.
21250 If SUBR is 1, we're being called recursively (to unify the
21251 arguments of a function or method parameter of a function
21252 template).
21254 CHECKS is a pointer to a vector of access checks encountered while
21255 substituting default template arguments. */
21257 static int
21259 tree full_targs,
21260 tree xparms,
21264 unification_kind_t strict,
21267 {
21272 tree parms;
21283 /* Reset the number of non-defaulted template arguments contained
21284 in TARGS. */
21287 again:
21295 {
21300 /* For a function parameter pack that occurs at the end of the
21301 parameter-declaration-list, the type A of each remaining
21302 argument of the call is compared with the type P of the
21303 declarator-id of the function parameter pack. */
21309 /* For a function parameter pack that does not occur at the
21310 end of the parameter-declaration-list, the type of the
21311 parameter pack is a non-deduced context. */
21318 explain_p))
21320 }
21325 {
21326 /* Unify the remaining arguments with the pack expansion type. */
21327 tree argvec;
21330 /* Allocate a TREE_VEC and copy in all of the arguments */
21335 /* Copy the parameter into parmvec. */
21341 /* Advance to the end of the list of parameters. */
21343 }
21345 /* Fail if we've reached the end of the parm list, and more args
21346 are present, and the parm list isn't variadic. */
21349 /* Fail if parms are left and they don't have default values and
21350 they aren't all deduced as empty packs (c++/57397). This is
21351 consistent with sufficient_parms_p. */
21354 {
21358 do
21359 {
21362 count++;
21364 }
21368 type_pack_p);
21369 }
21372 {
21373 tsubst_flags_t complain = (explain_p
21374 ? tf_warning_or_error
21379 {
21383 /* Clear the "incomplete" flags on all argument packs now so that
21384 substituting them into later default arguments works. */
21386 {
21389 }
21397 {
21402 }
21404 /* If this is an undeduced nontype parameter that depends on
21405 a type parameter, try another pass; its type may have been
21406 deduced from a later argument than the one from which
21407 this parameter can be deduced. */
21411 {
21414 }
21416 /* Core issue #226 (C++0x) [temp.deduct]:
21418 If a template argument has not been deduced, its
21419 default template argument, if any, is used.
21421 When we are in C++98 mode, TREE_PURPOSE will either
21422 be NULL_TREE or ERROR_MARK_NODE, so we do not need
21423 to explicitly check cxx_dialect here. */
21425 /* OK, there is a default argument. Wait until after the
21426 conversion check to do substitution. */
21429 /* If the type parameter is a parameter pack, then it will
21430 be deduced to an empty parameter pack. */
21432 {
21433 tree arg;
21436 {
21439 }
21440 else
21447 }
21450 }
21452 /* Now substitute into the default template arguments. */
21454 {
21470 {
21471 /* The type of this non-type parameter depends on undeduced
21472 parameters. Don't try to use its default argument yet,
21473 since we might deduce an argument for it on the next pass,
21474 but do check whether the arguments we already have cause
21475 substitution failure, so that that happens before we try
21476 later default arguments (78489). */
21479 NULL_TREE);
21483 else
21485 }
21486 else
21487 {
21488 /* Even if the call is happening in template context, getting
21489 here means it's non-dependent, and a default argument is
21490 considered a separate definition under [temp.decls], so we can
21491 do this substitution without processing_template_decl. This
21492 is important if the default argument contains something that
21493 might be instantiation-dependent like access (87480). */
21494 processing_template_decl_sentinel s;
21497 {
21498 /* First instatiate in template context, in case we still
21499 depend on undeduced template parameters. */
21502 NULL_TREE);
21506 /* We replaced all the tparms, substitute again out of
21507 template context. */
21509 }
21512 NULL_TREE);
21519 else
21521 }
21530 {
21532 /* The position of the first default template argument,
21533 is also the number of non-defaulted arguments in TARGS.
21534 Record that. */
21537 }
21538 }
21542 }
21548 }
21550 /* Subroutine of type_unification_real. Args are like the variables
21551 at the call site. ARG is an overloaded function (or template-id);
21552 we try deducing template args from each of the overloads, and if
21553 only one succeeds, we go with that. Modifies TARGS and returns
21554 true on success. */
21556 static bool
21558 tree targs,
21559 tree parm,
21560 tree arg,
21561 unification_kind_t strict,
21564 {
21571 {
21574 }
21575 else
21579 /* Handle `&x' where `x' is some static or non-static member
21580 function name. */
21586 /* Strip baselink information. */
21591 {
21592 /* If we got some explicit template args, we need to plug them into
21593 the affected templates before we try to unify, in case the
21594 explicit args will completely resolve the templates in question. */
21601 {
21614 {
21619 {
21622 }
21623 }
21626 }
21627 /* If no templates (or more than one) are fully resolved by the
21628 explicit arguments, this template-id is a non-deduced context; it
21629 could still be OK if we deduce all template arguments for the
21630 enclosing call through other arguments. */
21633 }
21635 /* If ARG is, for example, "(0, &f)" then its type will be unknown
21636 -- but the deduction does not succeed because the expression is
21637 not just the function on its own. */
21639 else
21641 {
21646 {
21649 }
21650 }
21652 /* [temp.deduct.type] A template-argument can be deduced from a pointer
21653 to function or pointer to member function argument if the set of
21654 overloaded functions does not contain function templates and at most
21655 one of a set of overloaded functions provides a unique match.
21657 So if we found multiple possibilities, we return success but don't
21658 deduce anything. */
21661 {
21665 {
21670 /* Don't forget explicit template arguments in a pack. */
21674 }
21675 }
21680 }
21682 /* Core DR 115: In contexts where deduction is done and fails, or in
21683 contexts where deduction is not done, if a template argument list is
21684 specified and it, along with any default template arguments, identifies
21685 a single function template specialization, then the template-id is an
21686 lvalue for the function template specialization. */
21688 tree
21690 {
21703 {
21706 }
21708 {
21711 }
21713 {
21716 }
21719 {
21723 /* If we got some explicit template args, we need to plug them into
21724 the affected templates before we try to unify, in case the
21725 explicit args will completely resolve the templates in question. */
21733 {
21746 {
21749 {
21752 }
21754 {
21757 }
21758 }
21759 }
21761 {
21769 {
21770 tree base
21773 }
21777 }
21779 /* There were no good options and at least one bad one, so let the
21780 user know what the problem is. */
21782 }
21784 }
21786 /* As above, but error out if the expression remains overloaded. */
21788 tree
21790 {
21793 {
21797 }
21799 }
21801 /* Subroutine of resolve_overloaded_unification; does deduction for a single
21802 overload. Fills TARGS with any deduced arguments, or error_mark_node if
21803 different overloads deduce different arguments for a given parm.
21804 ADDR_P is true if the expression for which deduction is being
21805 performed was of the form "& fn" rather than simply "fn".
21807 Returns 1 on success. */
21809 static int
21811 tree orig_targs,
21812 tree targs,
21813 tree parm,
21814 tree arg,
21815 unification_kind_t strict,
21819 {
21821 tree tempargs;
21827 /* [temp.deduct.type] A template-argument can be deduced from a pointer
21828 to function or pointer to member function argument if the set of
21829 overloaded functions does not contain function templates and at most
21830 one of a set of overloaded functions provides a unique match.
21832 So if this is a template, just return success. */
21844 /* We don't copy orig_targs for this because if we have already deduced
21845 some template args from previous args, unify would complain when we
21846 try to deduce a template parameter for the same argument, even though
21847 there isn't really a conflict. */
21854 /* First make sure we didn't deduce anything that conflicts with
21855 explicitly specified args. */
21857 {
21864 /* Since we're unifying against ourselves, we will fill in
21865 template args used in the function parm list with our own
21866 template parms. Discard them. */
21869 {
21870 /* Check that the argument at each index of the deduced argument pack
21871 is equivalent to the corresponding explicitly specified argument.
21872 We may have deduced more arguments than were explicitly specified,
21873 and that's OK. */
21875 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
21876 that's wrong if we deduce the same argument pack from multiple
21877 function arguments: it's only incomplete the first time. */
21890 }
21893 }
21896 {
21901 }
21904 }
21906 /* PARM is a template class (perhaps with unbound template
21907 parameters). ARG is a fully instantiated type. If ARG can be
21908 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
21909 TARGS are as for unify. */
21911 static tree
21914 {
21915 tree copy_of_targs;
21925 /* We need to make a new template argument vector for the call to
21926 unify. If we used TARGS, we'd clutter it up with the result of
21927 the attempted unification, even if this class didn't work out.
21928 We also don't want to commit ourselves to all the unifications
21929 we've already done, since unification is supposed to be done on
21930 an argument-by-argument basis. In other words, consider the
21931 following pathological case:
21933 template <int I, int J, int K>
21934 struct S {};
21936 template <int I, int J>
21937 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
21939 template <int I, int J, int K>
21940 void f(S<I, J, K>, S<I, I, I>);
21942 void g() {
21943 S<0, 0, 0> s0;
21944 S<0, 1, 2> s2;
21946 f(s0, s2);
21947 }
21949 Now, by the time we consider the unification involving `s2', we
21950 already know that we must have `f<0, 0, 0>'. But, even though
21951 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
21952 because there are two ways to unify base classes of S<0, 1, 2>
21953 with S<I, I, I>. If we kept the already deduced knowledge, we
21954 would reject the possibility I=1. */
21958 {
21962 }
21964 /* If unification failed, we're done. */
21970 }
21972 /* Given a template type PARM and a class type ARG, find the unique
21973 base type in ARG that is an instance of PARM. We do not examine
21974 ARG itself; only its base-classes. If there is not exactly one
21975 appropriate base class, return NULL_TREE. PARM may be the type of
21976 a partial specialization, as well as a plain template type. Used
21977 by unify. */
21979 static enum template_base_result
21982 {
21984 tree binfo;
21990 {
21991 /* The type could not be completed. */
21994 }
21996 /* Walk in inheritance graph order. The search order is not
21997 important, and this avoids multiple walks of virtual bases. */
21999 {
22004 {
22005 /* If there is more than one satisfactory baseclass, then:
22007 [temp.deduct.call]
22009 If they yield more than one possible deduced A, the type
22010 deduction fails.
22012 applies. */
22014 {
22017 }
22020 }
22021 }
22025 }
22027 /* Returns the level of DECL, which declares a template parameter. */
22029 static int
22031 {
22033 {
22043 }
22045 }
22047 /* Decide whether ARG can be unified with PARM, considering only the
22048 cv-qualifiers of each type, given STRICT as documented for unify.
22049 Returns nonzero iff the unification is OK on that basis. */
22051 static int
22053 {
22059 {
22060 /* Although a CVR qualifier is ignored when being applied to a
22061 substituted template parameter ([8.3.2]/1 for example), that
22062 does not allow us to unify "const T" with "int&" because both
22063 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
22064 It is ok when we're allowing additional CV qualifiers
22065 at the outer level [14.8.2.1]/3,1st bullet. */
22074 }
22085 }
22087 /* Determines the LEVEL and INDEX for the template parameter PARM. */
22088 void
22090 {
22094 {
22097 }
22098 else
22099 {
22102 }
22103 }
22105 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
22106 do { \
22107 if (unify (TP, TA, P, A, S, EP)) \
22108 return 1; \
22109 } while (0)
22111 /* Unifies the remaining arguments in PACKED_ARGS with the pack
22112 expansion at the end of PACKED_PARMS. Returns 0 if the type
22113 deduction succeeds, 1 otherwise. STRICT is the same as in
22114 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
22115 function call argument list. We'll need to adjust the arguments to make them
22116 types. SUBR tells us if this is from a recursive call to
22117 type_unification_real, or for comparing two template argument
22118 lists. */
22120 static int
22124 {
22125 tree parm
22131 /* Add in any args remembered from an earlier partial instantiation. */
22139 /* Determine the parameter packs we will be deducing from the
22140 pattern, and record their current deductions. */
22143 {
22147 /* Only template parameter packs can be deduced, not e.g. function
22148 parameter packs or __bases or __integer_pack. */
22152 /* Determine the index and level of this parameter pack. */
22157 /* Keep track of the parameter packs and their corresponding
22158 argument packs. */
22161 }
22163 /* Loop through all of the arguments that have not yet been
22164 unified and unify each with the pattern. */
22166 {
22167 tree parm;
22171 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
22172 or the element of its argument pack at the current index if
22173 this argument was explicitly specified. */
22175 {
22184 {
22187 }
22189 }
22191 /* If we had explicit template arguments, substitute them into the
22192 pattern before deduction. */
22194 {
22195 /* Some arguments might still be unspecified or dependent. */
22203 NULL_TREE);
22208 }
22209 else
22212 /* Unify the pattern with the current argument. */
22214 explain_p))
22217 /* For each parameter pack, collect the deduced value. */
22219 {
22225 }
22226 }
22228 /* Verify that the results of unification with the parameter packs
22229 produce results consistent with what we've seen before, and make
22230 the deduced argument packs available. */
22232 {
22239 /* By default keep the original deduced argument pack.
22240 If necessary, more specific code is going to update the
22241 resulting deduced argument later down in this function. */
22245 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
22246 actually deduce anything. */
22254 {
22255 /* If we had fewer function args than explicit template args,
22256 just use the explicits. */
22261 }
22264 {
22265 tree result;
22266 /* Build the deduced *_ARGUMENT_PACK. */
22268 {
22271 }
22272 else
22277 /* Note the deduced argument packs for this parameter
22278 pack. */
22280 }
22284 {
22285 /* We only had the explicitly-provided arguments before, but
22286 now we have a complete set of arguments. */
22292 }
22293 else
22294 {
22300 /* Inconsistent unification of this parameter pack. */
22302 bad_old_arg,
22303 bad_new_arg);
22304 }
22305 }
22308 }
22310 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
22311 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
22312 parameters and return value are as for unify. */
22314 static int
22318 {
22319 tree parm_max;
22320 tree arg_max;
22324 /* Our representation of array types uses "N - 1" as the
22325 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
22326 not an integer constant. We cannot unify arbitrarily
22327 complex expressions, so we eliminate the MINUS_EXPRs
22328 here. */
22332 {
22335 }
22339 {
22340 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
22341 trying to unify the type of a variable with the type
22342 of a template parameter. For example:
22344 template <unsigned int N>
22345 void f (char (&) [N]);
22346 int g();
22347 void h(int i) {
22348 char a[g(i)];
22349 f(a);
22350 }
22352 Here, the type of the ARG will be "int [g(i)]", and
22353 may be a SAVE_EXPR, etc. */
22357 }
22359 /* If only one of the bounds used a MINUS_EXPR, compensate
22360 by adding one to the other bound. */
22363 integer_type_node,
22364 parm_max,
22365 integer_one_node);
22368 integer_type_node,
22369 arg_max,
22370 integer_one_node);
22374 }
22376 /* Returns whether T, a P or A in unify, is a type, template or expression. */
22380 static pa_kind_t
22382 {
22391 else
22393 }
22395 /* Deduce the value of template parameters. TPARMS is the (innermost)
22396 set of template parameters to a template. TARGS is the bindings
22397 for those template parameters, as determined thus far; TARGS may
22398 include template arguments for outer levels of template parameters
22399 as well. PARM is a parameter to a template function, or a
22400 subcomponent of that parameter; ARG is the corresponding argument.
22401 This function attempts to match PARM with ARG in a manner
22402 consistent with the existing assignments in TARGS. If more values
22403 are deduced, then TARGS is updated.
22405 Returns 0 if the type deduction succeeds, 1 otherwise. The
22406 parameter STRICT is a bitwise or of the following flags:
22408 UNIFY_ALLOW_NONE:
22409 Require an exact match between PARM and ARG.
22410 UNIFY_ALLOW_MORE_CV_QUAL:
22411 Allow the deduced ARG to be more cv-qualified (by qualification
22412 conversion) than ARG.
22413 UNIFY_ALLOW_LESS_CV_QUAL:
22414 Allow the deduced ARG to be less cv-qualified than ARG.
22415 UNIFY_ALLOW_DERIVED:
22416 Allow the deduced ARG to be a template base class of ARG,
22417 or a pointer to a template base class of the type pointed to by
22418 ARG.
22419 UNIFY_ALLOW_INTEGER:
22420 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
22421 case for more information.
22422 UNIFY_ALLOW_OUTER_LEVEL:
22423 This is the outermost level of a deduction. Used to determine validity
22424 of qualification conversions. A valid qualification conversion must
22425 have const qualified pointers leading up to the inner type which
22426 requires additional CV quals, except at the outer level, where const
22427 is not required [conv.qual]. It would be normal to set this flag in
22428 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
22429 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
22430 This is the outermost level of a deduction, and PARM can be more CV
22431 qualified at this point.
22432 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
22433 This is the outermost level of a deduction, and PARM can be less CV
22434 qualified at this point. */
22436 static int
22439 {
22441 tree targ;
22442 tree tparm;
22444 tsubst_flags_t complain = (explain_p
22445 ? tf_warning_or_error
22448 /* I don't think this will do the right thing with respect to types.
22449 But the only case I've seen it in so far has been array bounds, where
22450 signedness is the only information lost, and I think that will be
22451 okay. */
22459 /* We can't deduce anything from this, but we might get all the
22460 template args from other function args. */
22466 /* If PARM uses template parameters, then we can't bail out here,
22467 even if ARG == PARM, since we won't record unifications for the
22468 template parameters. We might need them if we're trying to
22469 figure out which of two things is more specialized. */
22473 /* Handle init lists early, so the rest of the function can assume
22474 we're dealing with a type. */
22476 {
22483 /* We can only deduce from an initializer list argument if the
22484 parameter is std::initializer_list or an array; otherwise this
22485 is a non-deduced context. */
22490 else
22491 {
22493 /* Deduction is defined in terms of a single type, so just punt
22494 on the (bizarre) std::initializer_list<T...>. */
22497 }
22502 /* If ELTTYPE has no deducible template parms, skip deduction from
22504 else
22506 {
22513 {
22517 /* It should only be possible to get here for a call. */
22519 elt_strict |= maybe_adjust_types_for_deduction
22522 }
22525 explain_p);
22526 }
22530 {
22531 /* Also deduce from the length of the initializer list. */
22538 }
22540 /* If the std::initializer_list<T> deduction worked, replace the
22541 deduced A with std::initializer_list<A>. */
22543 {
22548 }
22550 }
22552 /* If parm and arg aren't the same kind of thing (template, type, or
22553 expression), fail early. */
22557 /* Immediately reject some pairs that won't unify because of
22558 cv-qualification mismatches. */
22561 /* It is the elements of the array which hold the cv quals of an array
22562 type, and the elements might be template type parms. We'll check
22563 when we recurse. */
22565 /* We check the cv-qualifiers when unifying with template type
22566 parameters below. We want to allow ARG `const T' to unify with
22567 PARM `T' for example, when computing which of two templates
22568 is more specialized, for example. */
22582 {
22586 /* In a type which contains a nested-name-specifier, template
22587 argument values cannot be deduced for template parameters used
22588 within the nested-name-specifier. */
22600 /* The PARM is not one we're trying to unify. Just check
22601 to see if it matches ARG. */
22602 {
22607 else
22609 }
22616 /* Check for mixed types and values. */
22624 {
22627 {
22628 /* First try to match ARG directly. */
22630 explain_p);
22632 {
22633 /* Otherwise, look for a suitable base of ARG, as below. */
22640 }
22641 }
22642 /* ARG must be constructed from a template class or a template
22643 template parameter. */
22648 /* Deduce arguments T, i from TT<T> or TT<i>. */
22654 /* Fall through to deduce template name. */
22655 }
22659 {
22660 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
22662 /* Simple cases: Value already set, does match or doesn't. */
22667 }
22668 else
22669 {
22670 /* If PARM is `const T' and ARG is only `int', we don't have
22671 a match unless we are allowing additional qualification.
22672 If ARG is `const int' and PARM is just `T' that's OK;
22673 that binds `const int' to `T'. */
22678 /* Consider the case where ARG is `const volatile int' and
22679 PARM is `const T'. Then, T should be `volatile int'. */
22680 arg = cp_build_qualified_type_real
22685 /* Simple cases: Value already set, does match or doesn't. */
22691 /* Make sure that ARG is not a variable-sized array. (Note
22692 that were talking about variable-sized arrays (like
22693 `int[n]'), rather than arrays of unknown size (like
22694 `int[]').) We'll get very confused by such a type since
22695 the bound of the array is not constant, and therefore
22696 not mangleable. Besides, such types are not allowed in
22697 ISO C++, so we can do as we please here. We do allow
22698 them for 'auto' deduction, since that isn't ABI-exposed. */
22702 /* Strip typedefs as in convert_template_argument. */
22704 }
22706 /* If ARG is a parameter pack or an expansion, we cannot unify
22707 against it unless PARM is also a parameter pack. */
22712 /* If the argument deduction results is a METHOD_TYPE,
22713 then there is a problem.
22714 METHOD_TYPE doesn't map to any real C++ type the result of
22715 the deduction cannot be of that type. */
22729 {
22730 /* The PARM is not one we're trying to unify. Just check
22731 to see if it matches ARG. */
22737 }
22743 {
22747 /* We're deducing from an array bound, the type doesn't matter. */
22753 }
22755 /* [temp.deduct.type] If, in the declaration of a function template
22756 with a non-type template-parameter, the non-type
22757 template-parameter is used in an expression in the function
22758 parameter-list and, if the corresponding template-argument is
22759 deduced, the template-argument type shall match the type of the
22760 template-parameter exactly, except that a template-argument
22761 deduced from an array bound may be of any integral type.
22762 The non-type parameter might use already deduced type parameters. */
22765 /* We don't have enough levels of args to do any substitution. This
22767 else
22768 {
22774 {
22778 }
22779 }
22782 /* Template-parameter dependent expression. Just accept it for now.
22783 It will later be processed in convert_template_argument. */
22784 ;
22788 /* OK. Ignore top-level quals here because a class-type template
22792 /* Convert the ARG to the type of PARM; the deduced non-type
22793 template argument must exactly match the types of the
22794 corresponding parameter. */
22797 {
22798 /* We haven't deduced the type of this parameter yet. */
22800 /* We deduce from array bounds in try_array_deduction. */
22802 {
22803 /* Deduce it from the non-type argument. */
22808 }
22809 else
22810 /* Try again later. */
22812 }
22813 else
22816 /* If ARG is a parameter pack or an expansion, we cannot unify
22817 against it unless PARM is also a parameter pack. */
22822 {
22825 }
22830 {
22831 /* A pointer-to-member constant can be unified only with
22832 another constant. */
22836 /* Just unify the class member. It would be useless (and possibly
22837 wrong, depending on the strict flags) to unify also
22838 PTRMEM_CST_CLASS, because we want to be sure that both parm and
22839 arg refer to the same variable, even if through different
22840 classes. For instance:
22842 struct A { int x; };
22843 struct B : A { };
22845 Unification of &A::x and &B::x must succeed. */
22848 }
22851 {
22855 /* [temp.deduct.call]
22857 A can be another pointer or pointer to member type that can
22858 be converted to the deduced A via a qualification
22859 conversion (_conv.qual_).
22861 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
22862 This will allow for additional cv-qualification of the
22863 pointed-to types if appropriate. */
22866 /* The derived-to-base conversion only persists through one
22867 level of pointers. */
22872 }
22904 /* We have already checked cv-qualification at the top of the
22905 function. */
22909 /* As far as unification is concerned, this wins. Later checks
22910 will invalidate it if necessary. */
22913 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
22914 /* Type INTEGER_CST can come from ordinary constant template args. */
22926 {
22936 /* Check for pack expansions in the parameters. */
22938 {
22940 {
22942 /* We can unify against something with a trailing
22943 parameter pack. */
22945 else
22946 /* [temp.deduct.type]/9: If the template argument list of
22947 P contains a pack expansion that is not the last
22948 template argument, the entire template argument list
22949 is a non-deduced context. */
22951 }
22952 }
22954 /* If we don't have enough arguments to satisfy the parameters
22955 (not counting the pack expression at the end), or we have
22956 too many arguments for a parameter list that doesn't end in
22957 a pack expression, we can't unify. */
22963 /* Unify all of the parameters that precede the (optional)
22964 pack expression. */
22966 {
22971 }
22974 DEDUCE_EXACT,
22977 }
22985 {
22993 }
22998 {
23002 {
23003 /* First, we try to unify the PARM and ARG directly. */
23008 {
23009 /* Fallback to the special case allowed in
23010 [temp.deduct.call]:
23012 If P is a class, and P has the form
23013 template-id, then A can be a derived class of
23014 the deduced A. Likewise, if P is a pointer to
23015 a class of the form template-id, A can be a
23016 pointer to a derived class pointed to by the
23017 deduced A. */
23023 {
23024 /* Don't give the derived diagnostic if we're
23025 already dealing with the same template. */
23026 bool same_template
23032 }
23033 }
23034 }
23038 /* Perhaps PARM is something like S<U> and ARG is S<int>.
23039 Then, we should unify `int' and `U'. */
23041 else
23042 /* There's no chance of unification succeeding. */
23047 }
23054 {
23057 tree a;
23063 /* CV qualifications for methods can never be deduced, they must
23064 match exactly. We need to check them explicitly here,
23065 because type_unification_real treats them as any other
23066 cv-qualified parameter. */
23068 && (!check_cv_quals_for_unify
23096 {
23108 }
23111 }
23114 /* Unify a pointer to member with a pointer to member function, which
23115 deduces the type of the member as a function type. */
23117 {
23118 /* Check top-level cv qualifiers */
23126 /* Determine the type of the function we are unifying against. */
23130 }
23149 /* Matched cases are handled by the ARG == PARM test above. */
23153 /* We might get a variable as a non-type template argument in parm if the
23154 corresponding parameter is type-dependent. Make any necessary
23155 adjustments based on whether arg is a reference. */
23159 {
23164 }
23165 /* Now use the normal expression code to check whether they match. */
23176 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
23177 or UNDERLYING_TYPE nodes. */
23181 /* Unification fails if we hit an error node. */
23186 {
23196 }
23197 /* FALLTHRU */
23200 /* An unresolved overload is a nondeduced context. */
23206 expr:
23207 /* We must be looking at an expression. This can happen with
23208 something like:
23210 template <int I>
23211 void foo(S<I>, S<I + 2>);
23213 or
23215 template<typename T>
23216 void foo(A<T, T{}>);
23218 This is a "non-deduced context":
23220 [deduct.type]
23222 The non-deduced contexts are:
23224 --A non-type template argument or an array bound in which
23225 a subexpression references a template parameter.
23227 In these cases, we assume deduction succeeded, but don't
23228 actually infer any unifications. */
23233 else
23235 }
23236 }
23237 #undef RECUR_AND_CHECK_FAILURE
23238 \f
23239 /* Note that DECL can be defined in this translation unit, if
23240 required. */
23242 static void
23244 {
23245 tree clone;
23249 }
23251 /* Called if RESULT is explicitly instantiated, or is a member of an
23252 explicitly instantiated class. */
23254 void
23256 {
23259 /* If this entity has already been written out, it's too late to
23260 make any modifications. */
23264 /* For anonymous namespace we don't need to do anything. */
23266 {
23269 }
23272 /* The TREE_PUBLIC flag for function declarations will have been
23273 set correctly by tsubst. */
23276 /* This might have been set by an earlier implicit instantiation. */
23281 else
23282 {
23285 /* Always make artificials weak. */
23288 /* For WIN32 we also want to put explicit instantiations in
23289 linkonce sections. */
23294 /* If the function has already been instantiated, clear DECL_EXTERNAL,
23295 since start_preparsed_function wouldn't have if we had an earlier
23296 extern explicit instantiation. */
23298 }
23300 /* If EXTERN_P, then this function will not be emitted -- unless
23301 followed by an explicit instantiation, at which point its linkage
23302 will be adjusted. If !EXTERN_P, then this function will be
23303 emitted here. In neither circumstance do we want
23304 import_export_decl to adjust the linkage. */
23306 }
23308 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
23309 important template arguments. If any are missing, we check whether
23310 they're important by using error_mark_node for substituting into any
23311 args that were used for partial ordering (the ones between ARGS and END)
23312 and seeing if it bubbles up. */
23314 static bool
23316 {
23321 {
23324 }
23326 {
23330 }
23332 }
23334 /* Given two function templates PAT1 and PAT2, return:
23336 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
23337 -1 if PAT2 is more specialized than PAT1.
23338 0 if neither is more specialized.
23340 LEN indicates the number of parameters we should consider
23341 (defaulted parameters should not be considered).
23343 The 1998 std underspecified function template partial ordering, and
23344 DR214 addresses the issue. We take pairs of arguments, one from
23345 each of the templates, and deduce them against each other. One of
23346 the templates will be more specialized if all the *other*
23347 template's arguments deduce against its arguments and at least one
23348 of its arguments *does* *not* deduce against the other template's
23349 corresponding argument. Deduction is done as for class templates.
23350 The arguments used in deduction have reference and top level cv
23351 qualifiers removed. Iff both arguments were originally reference
23352 types *and* deduction succeeds in both directions, an lvalue reference
23353 wins against an rvalue reference and otherwise the template
23354 with the more cv-qualified argument wins for that pairing (if
23355 neither is more cv-qualified, they both are equal). Unlike regular
23356 deduction, after all the arguments have been deduced in this way,
23357 we do *not* verify the deduced template argument values can be
23358 substituted into non-deduced contexts.
23360 The logic can be a bit confusing here, because we look at deduce1 and
23361 targs1 to see if pat2 is at least as specialized, and vice versa; if we
23362 can find template arguments for pat1 to make arg1 look like arg2, that
23363 means that arg2 is at least as specialized as arg1. */
23365 int
23367 {
23380 /* Remove the this parameter from non-static member functions. If
23381 one is a non-static member function and the other is not a static
23382 member function, remove the first parameter from that function
23383 also. This situation occurs for operator functions where we
23384 locate both a member function (with this pointer) and non-member
23385 operator (with explicit first operand). */
23387 {
23392 }
23394 {
23397 {
23398 len--;
23400 }
23401 }
23403 /* If only one is a conversion operator, they are unordered. */
23407 /* Consider the return type for a conversion function */
23409 {
23412 len++;
23413 }
23415 processing_template_decl++;
23421 /* Stop when an ellipsis is seen. */
23423 {
23434 {
23435 /* When both arguments are pack expansions, we need only
23436 unify the patterns themselves. */
23440 /* This is the last comparison we need to do. */
23442 }
23444 /* DR 1847: If a particular P contains no template-parameters that
23445 participate in template argument deduction, that P is not used to
23446 determine the ordering. */
23452 {
23456 }
23459 {
23463 }
23469 {
23475 /* Setup the parameter vector, which contains only ARG1. */
23478 /* Setup the argument vector, which contains the remaining
23479 arguments. */
23488 /* We cannot deduce in the other direction, because ARG1 is
23489 a pack expansion but ARG2 is not. */
23491 }
23493 {
23499 /* Setup the parameter vector, which contains only ARG1. */
23502 /* Setup the argument vector, which contains the remaining
23503 arguments. */
23512 /* We cannot deduce in the other direction, because ARG2 is
23513 a pack expansion but ARG1 is not.*/
23515 }
23517 else
23518 {
23519 /* The normal case, where neither argument is a pack
23520 expansion. */
23527 }
23529 /* If we couldn't deduce arguments for tparms1 to make arg1 match
23530 arg2, then arg2 is not as specialized as arg1. */
23536 /* "If, for a given type, deduction succeeds in both directions
23537 (i.e., the types are identical after the transformations above)
23538 and both P and A were reference types (before being replaced with
23539 the type referred to above):
23540 - if the type from the argument template was an lvalue reference and
23541 the type from the parameter template was not, the argument type is
23542 considered to be more specialized than the other; otherwise,
23543 - if the type from the argument template is more cv-qualified
23544 than the type from the parameter template (as described above),
23545 the argument type is considered to be more specialized than the other;
23546 otherwise,
23547 - neither type is more specialized than the other." */
23550 {
23552 {
23555 else
23557 }
23559 {
23564 }
23565 }
23568 /* We've failed to deduce something in either direction.
23569 These must be unordered. */
23572 next:
23576 /* We have already processed all of the arguments in our
23577 handing of the pack expansion type. */
23582 }
23584 /* "In most cases, all template parameters must have values in order for
23585 deduction to succeed, but for partial ordering purposes a template
23586 parameter may remain without a value provided it is not used in the
23587 types being used for partial ordering."
23589 Thus, if we are missing any of the targs1 we need to substitute into
23590 origs1, then pat2 is not as specialized as pat1. This can happen when
23591 there is a nondeduced context. */
23597 processing_template_decl--;
23599 /* If both deductions succeed, the partial ordering selects the more
23600 constrained template. */
23602 {
23608 }
23610 /* All things being equal, if the next argument is a pack expansion
23611 for one function but not for the other, prefer the
23612 non-variadic function. FIXME this is bogus; see c++/41958. */
23616 {
23619 }
23625 else
23627 }
23629 /* Determine which of two partial specializations of TMPL is more
23630 specialized.
23632 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
23633 to the first partial specialization. The TREE_PURPOSE is the
23634 innermost set of template parameters for the partial
23635 specialization. PAT2 is similar, but for the second template.
23637 Return 1 if the first partial specialization is more specialized;
23638 -1 if the second is more specialized; 0 if neither is more
23639 specialized.
23641 See [temp.class.order] for information about determining which of
23642 two templates is more specialized. */
23644 static int
23646 {
23647 tree targs;
23656 /* Just like what happens for functions, if we are ordering between
23657 different template specializations, we may encounter dependent
23658 types in the arguments, and we need our dependency check functions
23659 to behave correctly. */
23663 {
23666 }
23670 {
23673 }
23676 /* If both deductions succeed, the partial ordering selects the more
23677 constrained template. */
23681 /* In the case of a tie where at least one of the templates
23682 has a parameter pack at the end, the template with the most
23683 non-packed parameters wins. */
23685 && any_deductions
23688 {
23694 /* We don't count the pack expansion at the end. */
23704 }
23707 }
23709 /* Return the template arguments that will produce the function signature
23710 DECL from the function template FN, with the explicit template
23711 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
23712 also match. Return NULL_TREE if no satisfactory arguments could be
23713 found. */
23715 static tree
23717 {
23721 tree decl_arg_types;
23724 tree arg;
23728 /* Never do unification on the 'this' parameter. */
23750 }
23752 /* Return the innermost template arguments that, when applied to a partial
23753 specialization SPEC_TMPL of TMPL, yield the ARGS.
23755 For example, suppose we have:
23757 template <class T, class U> struct S {};
23758 template <class T> struct S<T*, int> {};
23760 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
23761 partial specialization and the ARGS will be {double*, int}. The resulting
23762 vector will be {double}, indicating that `T' is bound to `double'. */
23764 static tree
23766 {
23768 tree spec_args
23771 tree deduced_args;
23772 tree innermost_deduced_args;
23776 {
23780 innermost_deduced_args);
23781 }
23782 else
23786 again:
23795 {
23797 {
23803 }
23805 }
23808 {
23811 }
23813 /* Verify that nondeduced template arguments agree with the type
23814 obtained from argument deduction.
23816 For example:
23818 struct A { typedef int X; };
23819 template <class T, class U> struct C {};
23820 template <class T> struct C<T, typename T::X> {};
23822 Then with the instantiation `C<A, int>', we can deduce that
23823 `T' is `A' but unify () does not check whether `typename T::X'
23824 is `int'. */
23835 /* We only need to check the innermost arguments; the other
23836 arguments will always agree. */
23841 /* Now that we have bindings for all of the template arguments,
23842 ensure that the arguments deduced for the template template
23843 parameters have compatible template parameter lists. See the use
23844 of template_template_parm_bindings_ok_p in fn_type_unification
23845 for more information. */
23850 }
23852 // Compare two function templates T1 and T2 by deducing bindings
23853 // from one against the other. If both deductions succeed, compare
23854 // constraints to see which is more constrained.
23855 static int
23857 {
23862 {
23865 }
23868 {
23871 }
23873 // If both deductions succeed, then one may be more constrained.
23878 }
23880 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
23881 Return the TREE_LIST node with the most specialized template, if
23882 any. If there is no most specialized template, the error_mark_node
23883 is returned.
23885 Note that this function does not look at, or modify, the
23886 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
23887 returned is one of the elements of INSTANTIATIONS, callers may
23888 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
23889 and retrieve it from the value returned. */
23891 tree
23893 {
23900 {
23906 {
23907 /* Equally specialized, move to next function. If there
23908 is no next function, nothing's most specialized. */
23913 }
23914 }
23917 /* Now verify that champ is better than everything earlier in the
23918 instantiation list. */
23921 {
23924 }
23925 }
23927 processing_template_decl--;
23933 }
23935 /* If DECL is a specialization of some template, return the most
23936 general such template. Otherwise, returns NULL_TREE.
23938 For example, given:
23940 template <class T> struct S { template <class U> void f(U); };
23942 if TMPL is `template <class U> void S<int>::f(U)' this will return
23943 the full template. This function will not trace past partial
23944 specializations, however. For example, given in addition:
23946 template <class T> struct S<T*> { template <class U> void f(U); };
23948 if TMPL is `template <class U> void S<int*>::f(U)' this will return
23949 `template <class T> template <class U> S<T*>::f(U)'. */
23951 tree
23953 {
23955 {
23958 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
23959 template friend, or a FIELD_DECL for a capture pack. */
23962 }
23964 /* Look for more and more general templates. */
23966 {
23967 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
23968 (See cp-tree.h for details.) */
23977 /* Stop if we run into an explicitly specialized class template. */
23984 }
23987 }
23989 /* Return the most specialized of the template partial specializations
23990 which can produce TARGET, a specialization of some class or variable
23991 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
23992 a TEMPLATE_DECL node corresponding to the partial specialization, while
23993 the TREE_PURPOSE is the set of template arguments that must be
23994 substituted into the template pattern in order to generate TARGET.
23996 If the choice of partial specialization is ambiguous, a diagnostic
23997 is issued, and the error_mark_node is returned. If there are no
23998 partial specializations matching TARGET, then NULL_TREE is
23999 returned, indicating that the primary template should be used. */
24001 static tree
24003 {
24005 tree t;
24006 tree champ;
24013 {
24017 }
24019 {
24022 }
24024 {
24028 }
24029 else
24034 /* For determining which partial specialization to use, only the
24035 innermost args are interesting. */
24037 {
24040 }
24042 /* The caller hasn't called push_to_top_level yet, but we need
24043 get_partial_spec_bindings to be done in non-template context so that we'll
24044 fully resolve everything. */
24045 processing_template_decl_sentinel ptds;
24048 {
24049 tree spec_args;
24053 {
24054 /* Substitute in the template args from the enclosing class. */
24058 }
24065 {
24069 /* Keep the candidate only if the constraints are satisfied,
24070 or if we're not compiling with concepts. */
24073 {
24076 }
24077 }
24078 }
24088 {
24091 ;
24092 else
24093 {
24095 {
24098 {
24101 }
24102 }
24104 }
24105 }
24109 {
24112 {
24115 }
24116 }
24119 {
24126 else
24130 {
24135 }
24138 }
24141 }
24143 /* Explicitly instantiate DECL. */
24145 void
24147 {
24152 /* An error occurred, for which grokdeclarator has already issued
24153 an appropriate message. */
24156 {
24159 }
24161 {
24164 else
24167 }
24173 {
24174 /* There is an asymmetry here in the way VAR_DECLs and
24175 FUNCTION_DECLs are handled by grokdeclarator. In the case of
24176 the latter, the DECL we get back will be marked as a
24177 template instantiation, and the appropriate
24178 DECL_TEMPLATE_INFO will be set up. This does not happen for
24179 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
24180 should handle VAR_DECLs as it currently handles
24181 FUNCTION_DECLs. */
24183 {
24186 }
24189 {
24192 }
24194 {
24199 }
24200 }
24202 {
24205 }
24206 else
24209 /* Check for various error cases. Note that if the explicit
24210 instantiation is valid the RESULT will currently be marked as an
24211 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
24212 until we get here. */
24215 {
24216 /* DR 259 [temp.spec].
24218 Both an explicit instantiation and a declaration of an explicit
24219 specialization shall not appear in a program unless the explicit
24220 instantiation follows a declaration of the explicit specialization.
24222 For a given set of template parameters, if an explicit
24223 instantiation of a template appears after a declaration of an
24224 explicit specialization for that template, the explicit
24225 instantiation has no effect. */
24227 }
24229 {
24230 /* [temp.spec]
24232 No program shall explicitly instantiate any template more
24233 than once.
24235 We check DECL_NOT_REALLY_EXTERN so as not to complain when
24236 the first instantiation was `extern' and the second is not,
24237 and EXTERN_P for the opposite case. */
24240 /* If an "extern" explicit instantiation follows an ordinary
24241 explicit instantiation, the template is instantiated. */
24244 }
24246 {
24249 }
24251 {
24254 }
24257 ;
24259 {
24262 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
24265 }
24266 else
24274 }
24276 static void
24278 {
24284 {
24287 }
24288 }
24290 /* Called from do_type_instantiation through binding_table_foreach to
24291 do recursive instantiation for the type bound in ENTRY. */
24292 static void
24294 {
24301 }
24303 /* Perform an explicit instantiation of template class T. STORAGE, if
24304 non-null, is the RID for extern, inline or static. COMPLAIN is
24305 nonzero if this is called from the parser, zero if called recursively,
24306 since the standard is unclear (as detailed below). */
24308 void
24310 {
24320 {
24321 tree tmpl =
24325 else
24328 }
24333 {
24336 t);
24338 }
24341 {
24343 {
24345 {
24348 "ISO C++ 1998 forbids the use of %<extern%> on "
24350 }
24351 else
24353 "ISO C++ forbids the use of %qE"
24355 }
24363 else
24364 {
24366 storage);
24368 }
24369 }
24372 {
24373 /* DR 259 [temp.spec].
24375 Both an explicit instantiation and a declaration of an explicit
24376 specialization shall not appear in a program unless the explicit
24377 instantiation follows a declaration of the explicit specialization.
24379 For a given set of template parameters, if an explicit
24380 instantiation of a template appears after a declaration of an
24381 explicit specialization for that template, the explicit
24382 instantiation has no effect. */
24384 }
24386 {
24387 /* [temp.spec]
24389 No program shall explicitly instantiate any template more
24390 than once.
24392 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
24393 instantiation was `extern'. If EXTERN_P then the second is.
24394 These cases are OK. */
24401 /* If we've already instantiated the template, just return now. */
24404 }
24412 /* In contrast to implicit instantiation, where only the
24413 declarations, and not the definitions, of members are
24414 instantiated, we have here:
24416 [temp.explicit]
24418 The explicit instantiation of a class template specialization
24419 implies the instantiation of all of its members not
24420 previously explicitly specialized in the translation unit
24421 containing the explicit instantiation.
24423 Of course, we can't instantiate member template classes, since we
24424 don't have any arguments for them. Note that the standard is
24425 unclear on whether the instantiation of the members are
24426 *explicit* instantiations or not. However, the most natural
24427 interpretation is that it should be an explicit
24428 instantiation. */
24432 && !static_p
24435 {
24440 }
24445 }
24447 /* Given a function DECL, which is a specialization of TMPL, modify
24448 DECL to be a re-instantiation of TMPL with the same template
24449 arguments. TMPL should be the template into which tsubst'ing
24450 should occur for DECL, not the most general template.
24452 One reason for doing this is a scenario like this:
24454 template <class T>
24455 void f(const T&, int i);
24457 void g() { f(3, 7); }
24459 template <class T>
24460 void f(const T& t, const int i) { }
24462 Note that when the template is first instantiated, with
24463 instantiate_template, the resulting DECL will have no name for the
24464 first parameter, and the wrong type for the second. So, when we go
24465 to instantiate the DECL, we regenerate it. */
24467 static void
24469 {
24470 /* The arguments used to instantiate DECL, from the most general
24471 template. */
24472 tree code_pattern;
24476 /* Make sure that we can see identifiers, and compute access
24477 correctly. */
24481 {
24482 tree decl_parm;
24483 tree pattern_parm;
24484 tree specs;
24493 /* Instantiate a dynamic exception-specification. noexcept will be
24494 handled below. */
24497 {
24503 specs);
24504 }
24506 /* Merge parameter declarations. */
24509 pattern_parm
24513 {
24514 tree parm_type;
24515 tree attributes;
24520 NULL_TREE);
24526 {
24529 }
24532 }
24533 /* Merge any parameters that match with the function parameter
24534 pack. */
24536 {
24538 tree expanded_types;
24539 /* Expand the TYPE_PACK_EXPANSION that provides the types for
24540 the parameters in this function parameter pack. */
24545 {
24546 tree parm_type;
24547 tree attributes;
24550 /* Rename the parameter to include the index. */
24559 {
24562 }
24564 }
24565 }
24566 /* Merge additional specifiers from the CODE_PATTERN. */
24572 }
24574 {
24583 }
24584 else
24588 }
24590 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
24591 substituted to get DECL. */
24593 tree
24595 {
24598 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
24599 for the instantiation. This is not always the most general
24600 template. Consider, for example:
24602 template <class T>
24603 struct S { template <class U> void f();
24604 template <> void f<int>(); };
24606 and an instantiation of S<double>::f<int>. We want TD to be the
24607 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
24609 more general template. */
24611 /* We must also deal with friend templates. Given:
24613 template <class T> struct S {
24614 template <class U> friend void f() {};
24615 };
24617 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
24618 so far as the language is concerned, but that's still
24619 where we get the pattern for the instantiation from. On
24620 other hand, if the definition comes outside the class, say:
24622 template <class T> struct S {
24623 template <class U> friend void f();
24624 };
24625 template <class U> friend void f() {}
24627 we don't need to look any further. That's what the check for
24628 DECL_INITIAL is for. */
24632 {
24633 /* The present template, TD, should not be a definition. If it
24634 were a definition, we should be using it! Note that we
24635 cannot restructure the loop to just keep going until we find
24636 a template with a definition, since that might go too far if
24637 a specialization was declared, but not defined. */
24639 /* Fetch the more general template. */
24641 }
24644 }
24646 /* Returns true if we need to instantiate this template instance even if we
24647 know we aren't going to emit it. */
24649 bool
24651 {
24652 /* We always instantiate inline functions so that we can inline them. An
24653 explicit instantiation declaration prohibits implicit instantiation of
24654 non-inline functions. With high levels of optimization, we would
24655 normally inline non-inline functions -- but we're not allowed to do
24656 that for "extern template" functions. Therefore, we check
24657 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
24661 /* And we need to instantiate static data members so that
24662 their initializers are available in integral constant
24663 expressions. */
24666 }
24668 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
24669 instantiate it now, modifying TREE_TYPE (fn). Returns false on
24670 error, true otherwise. */
24672 bool
24674 {
24677 /* Don't instantiate a noexcept-specification from template context. */
24686 /* For a member friend template we can get a TEMPLATE_DECL. Let's use
24687 its FUNCTION_DECL for the rest of this function -- push_access_scope
24688 doesn't accept TEMPLATE_DECLs. */
24690 {
24693 }
24704 {
24708 {
24711 /* This might have failed because of an unparsed DMI, so
24712 let's try again later. */
24714 }
24716 {
24717 /* If hash_set::add returns true, the element was already there. */
24722 fn);
24724 }
24726 {
24732 /* If needed, set current_class_ptr for the benefit of
24733 tsubst_copy/PARM_DECL. */
24736 {
24741 }
24743 /* If this function is represented by a TEMPLATE_DECL, then
24744 the deferred noexcept-specification might still contain
24745 dependent types, even after substitution. And we need the
24746 dependency check functions to work in build_noexcept_spec. */
24750 /* Do deferred instantiation of the noexcept-specifier. */
24757 /* Build up the noexcept-specification. */
24767 }
24768 else
24775 {
24776 /* This failed with a hard error, so let's go with false. */
24779 }
24784 }
24787 {
24790 else
24792 }
24795 }
24797 /* We're starting to process the function INST, an instantiation of PATTERN;
24798 add their parameters to local_specializations. */
24800 static void
24802 {
24806 {
24810 }
24812 {
24814 {
24817 }
24818 else
24819 {
24820 /* Register the (value) argument pack as a specialization of
24821 TMPL_PARM, then move on. */
24824 }
24825 }
24827 }
24829 /* Produce the definition of D, a _DECL generated from a template. If
24830 DEFER_OK is true, then we don't have to actually do the
24831 instantiation now; we just have to do it sometime. Normally it is
24832 an error if this is an explicit instantiation but D is undefined.
24833 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
24834 instantiated class template. */
24836 tree
24838 {
24840 tree gen_args;
24841 tree args;
24842 tree td;
24843 tree code_pattern;
24844 tree spec;
24845 tree gen_tmpl;
24853 /* This function should only be used to instantiate templates for
24854 functions and static member variables. */
24857 /* A concept is never instantiated. */
24860 /* Variables are never deferred; if instantiation is required, they
24861 are instantiated right away. That allows for better code in the
24862 case that an expression refers to the value of the variable --
24863 if the variable has a constant value the referring expression can
24864 take advantage of that fact. */
24868 /* Don't instantiate cloned functions. Instead, instantiate the
24869 functions they cloned. */
24877 /* D has already been instantiated or explicitly specialized, so
24878 there's nothing for us to do here.
24880 It might seem reasonable to check whether or not D is an explicit
24881 instantiation, and, if so, stop here. But when an explicit
24882 instantiation is deferred until the end of the compilation,
24883 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
24884 the instantiation. */
24887 /* Check to see whether we know that this template will be
24888 instantiated in some other file, as with "extern template"
24889 extension. */
24892 /* In general, we do not instantiate such templates. */
24900 /* We should already have the extra args. */
24903 /* And what's in the hash table should match D. */
24907 /* This needs to happen before any tsubsting. */
24913 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
24914 for the instantiation. */
24919 {
24920 /* Look up an explicit specialization, if any. */
24924 {
24927 }
24928 }
24932 /* We should never be trying to instantiate a member of a class
24933 template or partial specialization. */
24938 /* In the case of a friend template whose definition is provided
24939 outside the class, we may have too many arguments. Drop the
24940 ones we don't need. The same is true for specializations. */
24941 args = get_innermost_template_args
24945 {
24951 }
24952 else
24953 {
24957 else
24959 }
24961 /* We may be in the middle of deferred access check. Disable it now. */
24964 /* Unless an explicit instantiation directive has already determined
24965 the linkage of D, remember that a definition is available for
24966 this entity. */
24976 /* If D is a member of an explicitly instantiated class template,
24977 and no definition is available, treat it like an implicit
24978 instantiation. */
24981 {
24982 /* Leave linkage flags alone on instantiations with anonymous
24983 visibility. */
24985 {
24988 }
24990 }
24992 /* Defer all other templates, unless we have been explicitly
24993 forbidden from doing so. */
24995 template. */
24996 ! pattern_defined
24997 /* If it's OK to postpone instantiation, do so. */
24998 || defer_ok
24999 /* If this is a static data member that will be defined
25000 elsewhere, we don't want to instantiate the entire data
25001 member, but we do want to instantiate the initializer so that
25002 we can substitute that elsewhere. */
25004 /* Handle here a deleted function too, avoid generating
25005 its body (c++/61080). */
25007 {
25008 /* The definition of the static data member is now required so
25009 we must substitute the initializer. */
25013 {
25014 tree ns;
25015 tree init;
25024 args,
25027 /* If instantiating the initializer involved instantiating this
25028 again, don't call cp_finish_decl twice. */
25030 {
25031 /* Make sure the initializer is still constant, in case of
25032 circular dependency (template/instantiate6.C). */
25033 const_init
25037 LOOKUP_ONLYCONVERTING);
25038 }
25042 }
25044 /* We restore the source position here because it's used by
25045 add_pending_template. */
25051 /* [temp.explicit]
25053 The definition of a non-exported function template, a
25054 non-exported member function template, or a non-exported
25055 member function or static data member of a class template
25056 shall be present in every translation unit in which it is
25057 explicitly instantiated. */
25061 /* If we're in unevaluated context, we just wanted to get the
25062 constant value; this isn't an odr use, so don't queue
25063 a full instantiation. */
25066 /* ??? Historically, we have instantiated inline functions, even
25067 when marked as "extern template". */
25071 }
25074 tree fn_context;
25077 /* tsubst_lambda_expr resolved any references to enclosing functions. */
25088 else
25089 {
25094 }
25096 /* Mark D as instantiated so that recursive calls to
25097 instantiate_decl do not try to instantiate it again. */
25100 /* Regenerate the declaration in case the template has been modified
25101 by a subsequent redeclaration. */
25104 /* We already set the file and line above. Reset them now in case
25105 they changed as a result of calling regenerate_decl_from_template. */
25109 {
25110 tree init;
25113 /* Clear out DECL_RTL; whatever was there before may not be right
25114 since we've reset the type of the declaration. */
25118 /* The initializer is placed in DECL_INITIAL by
25119 regenerate_decl_from_template so we don't need to
25120 push/pop_access_scope again here. Pull it out so that
25121 cp_finish_decl can process it. */
25126 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
25127 initializer. That function will defer actual emission until
25128 we have a chance to determine linkage. */
25131 /* Enter the scope of D so that access-checking works correctly. */
25146 }
25150 {
25151 /* Set up the list of local specializations. */
25155 /* Set up context. */
25159 else
25162 /* Some typedefs referenced from within the template code need to be
25163 access checked at template instantiation time, i.e now. These
25164 types were added to the template at parsing time. Let's get those
25165 and perform the access checks then. */
25167 args);
25169 /* Create substitution entries for the parameters. */
25172 /* Substitute into the body of the function. */
25176 else
25177 {
25182 /* Set the current input_location to the end of the function
25183 so that finish_function knows where we are. */
25184 input_location
25187 /* Remember if we saw an infinite loop in the template. */
25188 current_function_infinite_loop
25190 }
25192 /* Finish the function. */
25196 else
25197 {
25200 }
25204 }
25206 /* We're not deferring instantiation any more. */
25211 else
25217 out:
25226 }
25228 /* Run through the list of templates that we wish we could
25229 instantiate, and instantiate any we can. RETRIES is the
25230 number of times we retry pending template instantiation. */
25232 void
25234 {
25238 /* Instantiating templates may trigger vtable generation. This in turn
25239 may require further template instantiations. We place a limit here
25240 to avoid infinite loop. */
25242 {
25246 "template instantiation depth exceeds maximum of %d"
25247 " instantiating %q+D, possibly from virtual table generation"
25251 /* Pretend that we defined it. */
25254 }
25256 do
25257 {
25262 {
25267 {
25269 {
25284 }
25287 }
25288 else
25289 {
25292 {
25293 instantiation
25299 }
25303 }
25306 {
25307 /* If INSTANTIATION has been instantiated, then we don't
25308 need to consider it again in the future. */
25313 }
25314 else
25315 {
25318 }
25321 }
25323 }
25327 }
25329 /* Substitute ARGVEC into T, which is a list of initializers for
25330 either base class or a non-static data member. The TREE_PURPOSEs
25331 are DECLs, and the TREE_VALUEs are the initializer values. Used by
25332 instantiate_decl. */
25334 static tree
25336 {
25341 {
25342 tree decl;
25343 tree init;
25349 {
25350 tree expr;
25351 tree arg;
25353 /* Expand the base class expansion type into separate base
25354 classes. */
25356 tf_warning_or_error,
25357 NULL_TREE);
25361 /* We'll be building separate TREE_LISTs of arguments for
25362 each base. */
25368 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
25369 expand each argument in the TREE_VALUE of t. */
25376 /* VOID_TYPE_NODE is used to indicate
25377 value-initialization. */
25378 {
25381 }
25382 else
25383 {
25384 /* Substitute parameter packs into each argument in the
25385 TREE_LIST. */
25388 {
25389 tree expanded_exprs;
25391 /* Expand the argument. */
25393 expanded_exprs
25395 tf_warning_or_error,
25396 NULL_TREE);
25400 /* Prepend each of the expanded expressions to the
25401 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
25403 {
25408 }
25409 }
25412 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
25413 since we built them backwards. */
25415 {
25418 }
25419 }
25420 }
25423 {
25425 {
25429 }
25430 else
25431 {
25432 tree tmp;
25447 /* If we had an initializer but it instantiated to nothing,
25448 value-initialize the object. This will only occur when
25449 the initializer was a pack expansion where the parameter
25450 packs used in that expansion were of length zero. */
25453 }
25457 {
25459 decl);
25461 }
25462 /* Look for a target constructor. */
25466 {
25469 {
25473 }
25475 }
25478 {
25482 }
25483 }
25484 }
25486 }
25488 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
25490 static void
25492 {
25497 else
25499 }
25501 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
25502 is the instantiation (which should have been created with
25503 start_enum) and ARGS are the template arguments to use. */
25505 static void
25507 {
25508 tree e;
25514 {
25515 tree value;
25516 tree decl;
25519 /* Note that in a template enum, the TREE_VALUE is the
25520 CONST_DECL, not the corresponding INTEGER_CST. */
25525 /* Give this enumeration constant the correct access. */
25528 /* Actually build the enumerator itself. Here we're assuming that
25529 enumerators can't have dependent attributes. */
25532 }
25542 }
25544 /* DECL is a FUNCTION_DECL that is a template specialization. Return
25545 its type -- but without substituting the innermost set of template
25546 arguments. So, innermost set of template parameters will appear in
25547 the type. */
25549 tree
25551 {
25552 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
25554 }
25556 /* Return truthvalue if we're processing a template different from
25557 the last one involved in diagnostics. */
25558 bool
25560 {
25562 }
25564 /* Remember current template involved in diagnostics. */
25565 void
25567 {
25569 }
25573 {
25575 }
25577 /* Return TRUE if current_function_decl is being instantiated, false
25578 otherwise. */
25580 bool
25582 {
25586 }
25588 /* [temp.param] Check that template non-type parm TYPE is of an allowable
25589 type. Return false for ok, true for disallowed. Issue error and
25590 inform messages under control of COMPLAIN. */
25592 static bool
25594 {
25612 /* A bound template template parm could later be instantiated to have a valid
25613 nontype parm type via an alias template. */
25618 {
25620 {
25625 }
25631 {
25636 }
25638 {
25642 }
25643 /* FIXME check op<=> and strong structural equality once spaceship is
25644 implemented. */
25646 }
25649 {
25652 else
25654 type);
25655 }
25657 }
25659 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
25660 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
25662 static bool
25664 {
25665 tree scope;
25667 /* [temp.dep.type]
25669 A type is dependent if it is:
25671 -- a template parameter. Template template parameters are types
25672 for us (since TYPE_P holds true for them) so we handle
25673 them here. */
25677 /* -- a qualified-id with a nested-name-specifier which contains a
25678 class-name that names a dependent type or whose unqualified-id
25679 names a dependent type. */
25683 /* An alias template specialization can be dependent even if the
25684 resulting type is not. */
25688 /* -- a cv-qualified type where the cv-unqualified type is
25689 dependent.
25690 No code is necessary for this bullet; the code below handles
25691 cv-qualified types, and we don't want to strip aliases with
25692 TYPE_MAIN_VARIANT because of DR 1558. */
25693 /* -- a compound type constructed from any dependent type. */
25701 {
25702 tree arg_type;
25707 arg_type;
25712 /* A value-dependent noexcept-specifier makes the type dependent. */
25715 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
25716 affect overload resolution and treating it as dependent breaks
25717 things. Same for an unparsed noexcept expression. */
25723 }
25724 /* -- an array type constructed from any dependent type or whose
25725 size is specified by a constant expression that is
25726 value-dependent.
25728 We checked for type- and value-dependence of the bounds in
25729 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
25731 {
25736 }
25738 /* -- a template-id in which either the template name is a template
25739 parameter ... */
25742 /* ... or any of the template arguments is a dependent type or
25743 an expression that is type-dependent or value-dependent. */
25745 && (any_dependent_template_arguments_p
25749 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
25750 dependent; if the argument of the `typeof' expression is not
25751 type-dependent, then it should already been have resolved. */
25757 /* A template argument pack is dependent if any of its packed
25758 arguments are. */
25760 {
25766 }
25768 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
25769 be template parameters. */
25776 /* The standard does not specifically mention types that are local
25777 to template functions or local classes, but they should be
25778 considered dependent too. For example:
25780 template <int I> void f() {
25781 enum E { a = I };
25782 S<sizeof (E)> s;
25783 }
25785 The size of `E' cannot be known until the value of `I' has been
25786 determined. Therefore, `E' must be considered dependent. */
25790 /* Don't use type_dependent_expression_p here, as it can lead
25791 to infinite recursion trying to determine whether a lambda
25792 nested in a lambda is dependent (c++/47687). */
25796 && (any_dependent_template_arguments_p
25800 /* Other types are non-dependent. */
25802 }
25804 /* Returns TRUE if TYPE is dependent, in the sense of
25805 [temp.dep.type]. Note that a NULL type is considered dependent. */
25807 bool
25809 {
25810 /* If there are no template parameters in scope, then there can't be
25811 any dependent types. */
25813 {
25814 /* If we are not processing a template, then nobody should be
25815 providing us with a dependent type. */
25819 }
25821 /* If the type is NULL, we have not computed a type for the entity
25822 in question; in that case, the type is dependent. */
25826 /* Erroneous types can be considered non-dependent. */
25830 /* Getting here with global_type_node means we improperly called this
25831 function on the TREE_TYPE of an IDENTIFIER_NODE. */
25834 /* If we have not already computed the appropriate value for TYPE,
25835 do so now. */
25837 {
25840 }
25843 }
25845 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
25846 lookup. In other words, a dependent type that is not the current
25847 instantiation. */
25849 bool
25851 {
25854 }
25856 /* T is a SCOPE_REF. Return whether it represents a non-static member of
25857 an unknown base of 'this' (and is therefore instantiation-dependent). */
25859 static bool
25861 {
25878 }
25880 /* T is a SCOPE_REF; return whether we need to consider it
25881 instantiation-dependent so that we can check access at instantiation
25882 time even though we know which member it resolves to. */
25884 static bool
25886 {
25893 else
25895 }
25897 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
25898 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
25899 expression. */
25901 /* Note that this predicate is not appropriate for general expressions;
25902 only constant expressions (that satisfy potential_constant_expression)
25903 can be tested for value dependence. */
25905 bool
25907 {
25911 /* A type-dependent expression is also value-dependent. */
25916 {
25918 /* A dependent member function of the current instantiation. */
25922 /* A dependent member function of the current instantiation. */
25929 /* A name that has not been looked up -- must be dependent. */
25933 /* A non-type template parm. */
25937 /* A non-type template parm. */
25943 /* A constant with literal type and is initialized
25944 with an expression that is value-dependent. */
25946 /* FIXME cp_finish_decl doesn't fold reference initializers. */
25950 {
25953 /* __PRETTY_FUNCTION__ inside a template function is dependent
25954 on the name of the function. */
25956 /* It might be used in a template, but not a template
25957 function, in which case its DECL_VALUE_EXPR will be
25958 "top level". */
25961 }
25970 /* These expressions are value-dependent if the type to which
25971 the cast occurs is dependent or the expression being casted
25972 is value-dependent. */
25973 {
25979 /* A functional cast has a list of operands. */
25982 {
25983 /* If there are no operands, it must be an expression such
25984 as "int()". This should not happen for aggregate types
25985 because it would form non-constant expressions. */
25990 }
25996 }
26001 /* FALLTHRU */
26004 /* A `sizeof' expression is value-dependent if the operand is
26005 type-dependent or is a pack expansion. */
26014 /* An 'encode' expression is value-dependent if the operand is
26015 type-dependent. */
26024 /* All instantiation-dependent expressions should also be considered
26025 value-dependent. */
26033 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
26034 is value-dependent. */
26035 {
26044 }
26047 {
26064 }
26075 {
26079 }
26082 /* Treat all requires-expressions as value-dependent so
26083 we don't try to fold them. */
26090 {
26097 {
26099 /* In a call to a constexpr member function, look through the
26100 implicit ADDR_EXPR on the object argument so that it doesn't
26101 cause the call to be considered value-dependent. We also
26102 look through it in potential_constant_expression. */
26109 }
26111 }
26117 {
26119 tree val;
26126 }
26129 /* Treat a GNU statement expression as dependent to avoid crashing
26130 under instantiate_non_dependent_expr; it can't be constant. */
26134 /* A constant expression is value-dependent if any subexpression is
26135 value-dependent. */
26137 {
26144 {
26148 {
26151 /* In some cases, some of the operands may be missing.
26152 (For example, in the case of PREDECREMENT_EXPR, the
26153 amount to increment by may be missing.) That doesn't
26154 make the expression dependent. */
26157 }
26158 }
26162 }
26164 }
26166 /* The expression is not value-dependent. */
26168 }
26170 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
26171 [temp.dep.expr]. Note that an expression with no type is
26172 considered dependent. Other parts of the compiler arrange for an
26173 expression with type-dependent subexpressions to have no type, so
26174 this function doesn't have to be fully recursive. */
26176 bool
26178 {
26187 /* An unresolved name is always dependent. */
26193 /* A lambda-expression in template context is dependent. dependent_type_p is
26194 true for a lambda in the scope of a class or function template, but that
26195 doesn't cover all template contexts, like a default template argument. */
26199 /* A fold expression is type-dependent. */
26206 /* Some expression forms are never type-dependent. */
26220 /* The types of these expressions depends only on the type to which
26221 the cast occurs. */
26230 /* The types of these expressions depends only on the type created
26231 by the expression. */
26234 {
26235 /* For NEW_EXPR tree nodes created inside a template, either
26236 the object type itself or a TREE_LIST may appear as the
26237 operand 1. */
26240 /* This is an array type. We need to check array dimensions
26241 as well. */
26243 || value_dependent_expression_p
26245 else
26247 }
26250 {
26254 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
26255 contains an identifier associated by name lookup with one or more
26256 declarations declared with a dependent type, or...a
26257 nested-name-specifier or qualified-id that names a member of an
26258 unknown specialization. */
26261 }
26271 {
26272 tree elt;
26276 {
26279 }
26281 }
26283 /* A static data member of the current instantiation with incomplete
26284 array type is type-dependent, as the definition and specializations
26285 can have different bounds. */
26292 /* An array of unknown bound depending on a variadic parameter, eg:
26294 template<typename... Args>
26295 void foo (Args... args)
26296 {
26297 int arr[] = { args... };
26298 }
26300 template<int... vals>
26301 void bar ()
26302 {
26303 int arr[] = { vals... };
26304 }
26306 If the array has no length and has an initializer, it must be that
26307 we couldn't determine its length in cp_complete_array_type because
26308 it is dependent. */
26316 /* A function or variable template-id is type-dependent if it has any
26317 dependent template arguments. */
26321 {
26322 /* Consider the innermost template arguments, since those are the ones
26323 that come from the template-id; the template arguments for the
26324 enclosing class do not make it type-dependent unless they are used in
26325 the type of the decl. */
26327 && (any_dependent_template_arguments_p
26330 }
26332 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
26333 type-dependent. Checking this is important for functions with auto return
26334 type, which looks like a dependent type. */
26343 {
26347 }
26349 /* Always dependent, on the number of arguments if nothing else. */
26354 {
26359 {
26365 }
26366 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
26371 {
26376 }
26379 {
26386 }
26395 }
26397 /* The type of a non-type template parm declared with a placeholder type
26398 depends on the corresponding template argument, even though
26399 placeholders are not normally considered dependent. */
26406 /* Dependent type attributes might not have made it from the decl to
26407 the type yet. */
26413 }
26415 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
26416 type-dependent if the expression refers to a member of the current
26417 instantiation and the type of the referenced member is dependent, or the
26418 class member access expression refers to a member of an unknown
26419 specialization.
26421 This function returns true if the OBJECT in such a class member access
26422 expression is of an unknown specialization. */
26424 bool
26426 {
26427 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
26428 dependent. */
26433 }
26435 /* walk_tree callback function for instantiation_dependent_expression_p,
26436 below. Returns non-zero if a dependent subexpression is found. */
26438 static tree
26441 {
26443 {
26444 /* We don't have to worry about decltype currently because decltype
26445 of an instantiation-dependent expr is a dependent type. This
26446 might change depending on the resolution of DR 1172. */
26449 }
26452 {
26453 /* Don't treat an argument list as dependent just because it has no
26454 TREE_TYPE. */
26465 /* We'll check value-dependence separately. */
26468 /* Handle expressions with type operands. */
26473 {
26478 {
26481 else
26482 {
26485 }
26486 }
26488 }
26492 /* In a template, finish_class_member_access_expr creates a
26493 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
26494 type-dependent, so that we can check access control at
26495 instantiation time (PR 42277). See also Core issue 1273. */
26502 else
26505 /* Treat statement-expressions as dependent. */
26509 /* Treat requires-expressions as dependent. */
26514 /* Treat concept checks as dependent. */
26520 /* Treat concept checks as dependent. */
26532 }
26536 else
26538 }
26540 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
26541 sense defined by the ABI:
26543 "An expression is instantiation-dependent if it is type-dependent
26544 or value-dependent, or it has a subexpression that is type-dependent
26545 or value-dependent."
26547 Except don't actually check value-dependence for unevaluated expressions,
26548 because in sizeof(i) we don't care about the value of i. Checking
26549 type-dependence will in turn check value-dependence of array bounds/template
26550 arguments as needed. */
26552 bool
26554 {
26555 tree result;
26566 }
26568 /* As above, but also check value-dependence of the expression as a whole. */
26570 bool
26572 {
26575 }
26577 /* Like type_dependent_expression_p, but it also works while not processing
26578 a template definition, i.e. during substitution or mangling. */
26580 bool
26582 {
26588 }
26590 /* Returns TRUE if ARGS contains a type-dependent expression. */
26592 bool
26594 {
26596 tree arg;
26599 {
26602 }
26604 }
26606 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
26607 expressions) contains any type-dependent expressions. */
26609 bool
26611 {
26617 }
26619 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
26620 expressions) contains any value-dependent expressions. */
26622 bool
26624 {
26630 }
26632 /* Returns TRUE if the ARG (a template argument) is dependent. */
26634 bool
26636 {
26640 /* Assume a template argument that was wrongly written by the user
26641 is dependent. This is consistent with what
26642 any_dependent_template_arguments_p [that calls this function]
26643 does. */
26653 {
26656 /* A member template of a dependent class is not necessarily
26657 type-dependent, but it is a dependent template argument because it
26658 will be a member of an unknown specialization to that template. */
26661 }
26663 {
26667 {
26670 }
26673 }
26676 else
26679 }
26681 /* Returns true if ARGS (a collection of template arguments) contains
26682 any types that require structural equality testing. */
26684 bool
26686 {
26696 {
26699 {
26705 {
26706 /* Look inside the argument pack. */
26709 }
26712 {
26725 }
26726 }
26727 }
26730 }
26732 /* Returns true if ARGS (a collection of template arguments) contains
26733 any dependent arguments. */
26735 bool
26737 {
26747 {
26752 }
26755 }
26757 /* Returns true if ARGS contains any errors. */
26759 bool
26761 {
26769 {
26772 else
26774 }
26780 {
26785 }
26788 }
26790 /* Returns TRUE if the template TMPL is type-dependent. */
26792 bool
26794 {
26796 {
26801 }
26803 /* Template template parameters are dependent. */
26807 /* So are names that have not been looked up. */
26811 }
26813 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
26815 bool
26817 {
26820 }
26822 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
26823 are dependent. */
26825 bool
26827 {
26834 {
26859 {
26863 }
26867 {
26871 {
26877 /* If this loop has a class iterator with != comparison
26878 with increment other than i++/++i/i--/--i, make sure the
26879 increment is constant. */
26882 {
26885 else
26889 }
26890 }
26891 }
26892 }
26895 }
26897 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
26898 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
26899 no such TYPE can be found. Note that this function peers inside
26900 uninstantiated templates and therefore should be used only in
26901 extremely limited situations. ONLY_CURRENT_P restricts this
26902 peering to the currently open classes hierarchy (which is required
26903 when comparing types). */
26905 tree
26907 {
26908 tree scope;
26909 tree name;
26910 tree decl;
26912 tree pushed_scope;
26913 tree result;
26918 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
26921 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
26922 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
26923 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
26924 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
26925 identifier of the TYPENAME_TYPE anymore.
26926 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
26927 TYPENAME_TYPE instead, we avoid messing up with a possible
26928 typedef variant case. */
26931 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
26932 it first before we can figure out what NAME refers to. */
26934 {
26936 /* Given a class template A with a dependent base with nested type C,
26937 typedef typename A::C::C C will land us here, as trying to resolve
26938 the initial A::C leads to the local C typedef, which leads back to
26939 A::C::C. So we break the recursion now. */
26941 else
26943 }
26944 /* If we don't know what SCOPE refers to, then we cannot resolve the
26945 TYPENAME_TYPE. */
26948 /* If this is a typedef, we don't want to look inside (c++/11987). */
26951 /* If SCOPE isn't the template itself, it will not have a valid
26952 TYPE_FIELDS list. */
26954 /* scope is either the template itself or a compatible instantiation
26955 like X<T>, so look up the name in the original template. */
26957 /* If scope has no fields, it can't be a current instantiation. Check this
26958 before currently_open_class to avoid infinite recursion (71515). */
26961 /* If the SCOPE is not the current instantiation, there's no reason
26962 to look inside it. */
26965 /* Enter the SCOPE so that name lookup will be resolved as if we
26966 were in the class definition. In particular, SCOPE will no
26967 longer be considered a dependent type. */
26969 /* Look up the declaration. */
26971 tf_warning_or_error);
26975 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
26976 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
26982 {
26986 }
26989 {
26990 /* Obtain the template and the arguments. */
26993 {
26994 /* We get here with a plain identifier because a previous tentative
26995 parse of the nested-name-specifier as part of a ptr-operator saw
26996 ::template X<A>. The use of ::template is necessary in a
26997 ptr-operator, but wrong in a declarator-id.
26999 [temp.names]: In a qualified-id of a declarator-id, the keyword
27000 template shall not appear at the top level. */
27004 }
27006 /* Instantiate the template. */
27012 }
27014 /* Leave the SCOPE. */
27018 /* If we failed to resolve it, return the original typename. */
27022 /* If lookup found a typename type, resolve that too. */
27024 {
27025 /* Ill-formed programs can cause infinite recursion here, so we
27026 must catch that. */
27030 }
27032 /* Qualify the resulting type. */
27038 }
27040 /* EXPR is an expression which is not type-dependent. Return a proxy
27041 for EXPR that can be used to compute the types of larger
27042 expressions containing EXPR. */
27044 tree
27046 {
27048 tree inner_expr;
27050 /* When checking, try to get a constant value for all non-dependent
27051 expressions in order to expose bugs in *_dependent_expression_p
27052 and constexpr. This can affect code generation, see PR70704, so
27053 only do this for -fchecking=2. */
27056 /* Don't do this during nsdmi parsing as it can lead to
27057 unexpected recursive instantiations. */
27059 /* Don't do this during concept processing either and for
27060 the same reason. */
27066 /* Preserve OVERLOADs; the functions must be available to resolve
27067 types. */
27078 /* There is no need to return a proxy for a variable or enumerator. */
27081 /* Preserve string constants; conversions from string constants to
27082 "char *" are allowed, even though normally a "const char *"
27083 cannot be used to initialize a "char *". */
27086 /* Preserve void and arithmetic constants, as an optimization -- there is no
27087 reason to create a new node. */
27092 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
27093 There is at least one place where we want to know that a
27094 particular expression is a throw-expression: when checking a ?:
27095 expression, there are special rules if the second or third
27096 argument is a throw-expression. */
27100 /* Don't wrap an initializer list, we need to be able to look inside. */
27104 /* Don't wrap a dummy object, we need to be able to test for it. */
27123 /* If the type is unknown, it can't really be non-dependent */
27126 /* Otherwise, build a NON_DEPENDENT_EXPR. */
27129 }
27131 /* ARGS is a vector of expressions as arguments to a function call.
27132 Replace the arguments with equivalent non-dependent expressions.
27133 This modifies ARGS in place. */
27135 void
27137 {
27139 tree arg;
27142 {
27146 }
27147 }
27149 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
27150 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
27151 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
27153 static tree
27155 {
27168 }
27170 tree
27172 {
27174 }
27176 tree
27178 {
27180 }
27182 /* Return a C++17 deduction placeholder for class template TMPL. */
27184 tree
27186 {
27189 /* Our canonical type depends on the placeholder. */
27192 }
27194 /* True iff T is a C++17 class template deduction placeholder. */
27196 bool
27198 {
27200 }
27202 /* Make a "constrained auto" type-specifier. This is an auto or
27203 decltype(auto) type with constraints that must be associated after
27204 deduction. The constraint is formed from the given concept CON
27205 and its optional sequence of template arguments ARGS.
27207 TYPE must be the result of make_auto_type or make_decltype_auto_type. */
27209 static tree
27211 {
27212 /* Build the constraint. */
27221 /* Our canonical type depends on the constraint. */
27224 /* Attach the constraint to the type declaration. */
27226 }
27228 /* Make a "constrained auto" type-specifier. */
27230 tree
27232 {
27235 }
27237 /* Make a "constrained decltype(auto)" type-specifier. */
27239 tree
27241 {
27243 /* FIXME: I don't know why this isn't done in make_auto_1. */
27246 }
27248 /* Build and return a concept definition. Like other templates, the
27249 CONCEPT_DECL node is wrapped by a TEMPLATE_DECL. This returns the
27250 the TEMPLATE_DECL. */
27252 tree
27254 {
27260 /* A concept-definition shall not have associated constraints. */
27262 {
27265 }
27267 /* A concept-definition shall appear in namespace scope. Templates
27268 aren't allowed in block scope, so we only need to check for class
27269 scope. */
27271 {
27274 }
27276 /* Initially build the concept declaration; it's type is bool. */
27281 /* Push the enclosing template. */
27283 }
27285 /* Given type ARG, return std::initializer_list<ARG>. */
27287 static tree
27289 {
27293 {
27297 "deducing from brace-enclosed initializer list"
27301 }
27307 }
27309 /* Replace auto in TYPE with std::initializer_list<auto>. */
27311 static tree
27313 {
27320 }
27322 /* Hash traits for hashing possibly constrained 'auto'
27323 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
27326 {
27329 };
27331 /* Hash the 'auto' T. */
27333 inline hashval_t
27335 {
27337 /* Matching constrained-type-specifiers denote the same template
27338 parameter, so hash the constraint. */
27340 else
27341 /* But unconstrained autos are all separate, so just hash the pointer. */
27343 }
27345 /* Compare two 'auto's. */
27349 {
27356 /* Two unconstrained autos are distinct. */
27361 }
27363 /* for_each_template_parm callback for extract_autos: if t is a (possibly
27364 constrained) auto, add it to the vector. */
27366 static int
27368 {
27371 {
27372 /* All the autos were built with index 0; fix that up now. */
27376 /* If this is a repeated constrained-type-specifier, use the index we
27377 chose before. */
27379 else
27380 {
27381 /* Otherwise this is new, so use the current count. */
27384 }
27386 }
27388 /* Always keep walking. */
27390 }
27392 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
27393 says they can appear anywhere in the type. */
27395 static tree
27397 {
27406 {
27411 }
27414 }
27416 /* The stem for deduction guide names. */
27419 /* Return the name for a deduction guide for class template TMPL. */
27421 tree
27423 {
27434 }
27436 /* True if NAME is the name of a deduction guide. */
27438 bool
27440 {
27445 }
27447 /* True if FN is a deduction guide. */
27449 bool
27451 {
27456 }
27458 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
27460 bool
27462 {
27469 }
27471 /* True if FN is a guide generated from a constructor template. */
27473 bool
27475 {
27483 }
27485 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
27486 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
27487 template parameter types. Note that the handling of template template
27488 parameters relies on current_template_parms being set appropriately for the
27489 new template. */
27491 static tree
27494 {
27500 tree newtype;
27503 {
27510 }
27511 else
27512 {
27515 {
27516 // Substitute once to fix references to other template parameters.
27519 // Now substitute again to reduce the level of the auto.
27522 }
27523 else
27526 }
27528 tree newdecl
27533 tree newidx;
27536 {
27546 {
27551 // First create a copy (ttargs) of tsubst_args with an
27552 // additional level for the template template parameter's own
27553 // template parameters (ttparms).
27554 tree ttparms = (INNERMOST_TEMPLATE_PARMS
27562 // Substitute ttargs into ttparms to fix references to
27563 // other template parameters.
27566 // Now substitute again with args based on tparms, to reduce
27567 // the level of the ttparms.
27570 complain);
27571 // Finally, tack the adjusted parms onto tparms.
27573 current_template_parms);
27575 }
27576 }
27577 else
27578 {
27580 tree newconst
27592 }
27595 }
27597 /* Returns a C++17 class deduction guide template based on the constructor
27598 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
27599 guide, or REFERENCE_TYPE for an implicit copy/move guide. */
27601 static tree
27603 {
27607 location_t loc;
27611 {
27615 {
27618 }
27619 else
27629 }
27630 else
27631 {
27635 fn_tmpl
27645 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
27646 fully specialized args for the enclosing class. Strip those off, as
27647 the deduction guide won't have those template parameters. */
27650 /* Discard the 'this' parameter. */
27658 {
27661 /* For a member template constructor, we need to flatten the two
27662 template parameter lists into one, and then adjust the function
27663 signature accordingly. This gets...complicated. */
27666 /* For a member template we should have two levels of parms/args, one
27667 for the class and one for the constructor. We stripped
27668 specialized args for further enclosing classes above. */
27672 /* Template args for translating references to the two-level template
27673 parameters into references to the one-level template parameters we
27674 are creating. */
27679 /* Template parms for the constructor template. */
27682 /* Template parms for the class template. */
27686 /* Template parms for the deduction guide start as a copy of the
27687 template parms for the class. We set current_template_parms for
27688 lookup_template_class_1. */
27694 /* Now we need to rewrite the constructor parms to append them to the
27695 class parms. */
27697 {
27714 }
27716 /* Now we have a final set of template parms to substitute into the
27717 function signature. */
27728 }
27733 }
27736 {
27737 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
27741 }
27745 FUNCTION_DECL,
27762 }
27764 /* Deduce template arguments for the class template placeholder PTYPE for
27765 template TMPL based on the initializer INIT, and return the resulting
27766 type. */
27768 static tree
27770 tsubst_flags_t complain)
27771 {
27773 {
27774 /* We should have handled this in the caller. */
27780 }
27782 /* Using the template parm as its own argument. */
27795 {
27798 {
27799 /* As an exception, the first phase in 16.3.1.7 (considering the
27800 initializer list as a single argument) is omitted if the
27801 initializer list consists of a single expression of type cv U,
27802 where U is a specialization of C or a class derived from a
27803 specialization of C. */
27806 {
27808 tree tparms = (INNERMOST_TEMPLATE_PARMS
27816 }
27817 }
27820 else
27822 }
27823 else
27834 /* Prune explicit deduction guides in copy-initialization context. */
27836 {
27842 {
27843 /* Found a nonconverting guide, prune the candidates. */
27850 }
27851 }
27856 {
27859 }
27862 // FIXME cache artificial deduction guides
27864 {
27865 /* Skip inherited constructors. */
27875 else
27879 }
27883 /* If this is list-initialization and the class has a list constructor, first
27884 try deducing from the list as a single argument, as [over.match.list]. */
27888 {
27892 }
27894 {
27900 {
27901 /* That didn't work, now try treating the list as a sequence of
27902 arguments. */
27905 }
27906 }
27908 /* Maybe generate an implicit deduction guide. */
27910 {
27914 /* Generate a copy guide. */
27917 /* Generate a default guide. */
27921 {
27926 }
27927 }
27930 {
27932 " of %qT, as it has no non-explicit deduction guides or "
27935 }
27937 {
27941 }
27944 {
27948 }
27951 {
27961 }
27964 }
27966 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
27967 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
27968 The CONTEXT determines the context in which auto deduction is performed
27969 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
27970 OUTER_TARGS are used during template argument deduction
27971 (context == adc_unify) to properly substitute the result, and is ignored
27972 in other contexts.
27974 For partial-concept-ids, extra args may be appended to the list of deduced
27975 template arguments prior to determining constraint satisfaction. */
27977 tree
27981 {
27982 tree targs;
27989 /* Defining a subset of type-dependent expressions that we can deduce
27990 from ahead of time isn't worth the trouble. */
27993 /* Similarly, we can't deduce from another undeduced decl. */
27997 /* We may be doing a partial substitution, but we still want to replace
27998 auto_node. */
28002 /* C++17 class template argument deduction. */
28006 /* Nothing we can do with this, even in deduction context. */
28009 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
28010 with either a new invented type template parameter U or, if the
28011 initializer is a braced-init-list (8.5.4), with
28012 std::initializer_list<U>. */
28014 {
28019 else
28020 {
28022 {
28026 "for deduction to %<std::initializer_list%>, use copy-"
28028 }
28030 }
28031 }
28042 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
28043 and initializer has array type, deduce cv-qualified array type. */
28045 complain);
28047 {
28057 {
28061 }
28062 }
28063 else
28064 {
28069 tree tparms;
28073 else
28074 {
28078 }
28082 DEDUCE_CALL,
28085 {
28087 /* Try again at instantiation time. */
28091 /* If type is error_mark_node a diagnostic must have been
28092 emitted by now. Also, having a mention to '<type error>'
28093 in the diagnostic is not really useful to the user. */
28094 {
28097 && (auto_node
28101 else
28104 DEDUCE_CALL,
28106 }
28108 }
28109 }
28111 /* Check any placeholder constraints against the deduced type. */
28114 {
28115 /* Use the deduced type to check the associated constraints. If we
28116 have a partial-concept-id, rebuild the argument list so that
28117 we check using the extra arguments. */
28125 {
28128 }
28129 else
28132 /* Rebuild the check using the deduced arguments. */
28136 {
28138 {
28139 auto_diagnostic_group d;
28141 {
28159 }
28161 }
28163 }
28164 }
28170 }
28172 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
28173 result. */
28175 tree
28177 {
28179 {
28185 /* In an abbreviated function template we didn't know we were dealing
28186 with a function template when we saw the auto return type, so update
28187 it to have the correct level. */
28189 }
28191 }
28193 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
28194 'decltype(auto)' or a deduced class template. */
28196 bool
28198 {
28203 else
28205 }
28207 /* for_each_template_parm callback for type_uses_auto. */
28209 int
28211 {
28213 }
28215 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
28216 a use of `auto'. Returns NULL_TREE otherwise. */
28218 tree
28220 {
28224 {
28225 /* The Concepts TS allows multiple autos in one type-specifier; just
28226 return the first one we find, do_auto_deduction will collect all of
28227 them. */
28231 else
28233 }
28234 else
28236 }
28238 /* Report ill-formed occurrences of auto types in ARGUMENTS. If
28239 concepts are enabled, auto is acceptable in template arguments, but
28240 only when TEMPL identifies a template class. Return TRUE if any
28241 such errors were reported. */
28243 bool
28245 {
28246 /* If there were previous errors, nevermind. */
28250 /* If TMPL is an identifier, we're parsing and we can't tell yet
28251 whether TMPL is supposed to be a type, a function or a variable.
28252 We'll only be able to tell during template substitution, so we
28253 expect to be called again then. If concepts are enabled and we
28254 know we have a type, we're ok. */
28262 /* Quickly search for any occurrences of auto; usually there won't
28263 be any, and then we'll avoid allocating the vector. */
28271 {
28276 }
28279 }
28281 /* For a given template T, return the vector of typedefs referenced
28282 in T for which access check is needed at T instantiation time.
28283 T is either a FUNCTION_DECL or a RECORD_TYPE.
28284 Those typedefs were added to T by the function
28285 append_type_to_template_for_access_check. */
28289 {
28290 tree ti;
28301 {
28306 }
28309 }
28311 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
28312 tied to T. That list of typedefs will be access checked at
28313 T instantiation time.
28314 T is either a FUNCTION_DECL or a RECORD_TYPE.
28315 TYPE_DECL is a TYPE_DECL node representing a typedef.
28316 SCOPE is the scope through which TYPE_DECL is accessed.
28317 LOCATION is the location of the usage point of TYPE_DECL.
28319 This function is a subroutine of
28320 append_type_to_template_for_access_check. */
28322 static void
28324 tree type_decl,
28325 tree scope,
28326 location_t location)
28327 {
28328 qualified_typedef_usage_t typedef_usage;
28329 tree ti;
28336 && type_decl
28350 }
28352 /* Append TYPE_DECL to the template TEMPL.
28353 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
28354 At TEMPL instanciation time, TYPE_DECL will be checked to see
28355 if it can be accessed through SCOPE.
28356 LOCATION is the location of the usage point of TYPE_DECL.
28358 e.g. consider the following code snippet:
28360 class C
28361 {
28362 typedef int myint;
28363 };
28365 template<class U> struct S
28366 {
28367 C::myint mi; // <-- usage point of the typedef C::myint
28368 };
28370 S<char> s;
28372 At S<char> instantiation time, we need to check the access of C::myint
28373 In other words, we need to check the access of the myint typedef through
28374 the C scope. For that purpose, this function will add the myint typedef
28375 and the scope C through which its being accessed to a list of typedefs
28376 tied to the template S. That list will be walked at template instantiation
28377 time and access check performed on each typedefs it contains.
28378 Note that this particular code snippet should yield an error because
28379 myint is private to C. */
28381 void
28383 tree type_decl,
28384 tree scope,
28385 location_t location)
28386 {
28392 /* Make sure we don't append the type to the template twice. */
28399 }
28401 /* Recursively walk over && expressions searching for EXPR. Return a reference
28402 to that expression. */
28405 {
28409 {
28414 }
28416 }
28418 /* Convert the generic type parameters in PARM that match the types given in the
28419 range [START_IDX, END_IDX) from the current_template_parms into generic type
28420 packs. */
28422 tree
28424 {
28435 {
28436 /* Create a distinct parameter pack type from the current parm and add it
28437 to the replacement args to tsubst below into the generic function
28438 parameter. */
28452 /* Replace the current template parameter with new pack. */
28455 /* Surgically adjust the associated constraint of adjusted parameter
28456 and it's corresponding contribution to the current template
28457 requirements. */
28459 {
28465 /* If there was a constraint, we also need to replace that in
28466 the template requirements, which we've already built. */
28470 }
28471 }
28477 /* If there are more levels then build up the replacement with the outer
28478 template parms. */
28482 replacement);
28485 }
28487 /* A mapping from declarations to constraint information. Note that
28488 both templates and their underlying declarations are mapped to the
28489 same constraint information.
28491 FIXME: This is defined in pt.c because garbage collection
28492 code is not being generated for constraint.cc. */
28496 /* Returns the template constraints of declaration T. If T is not
28497 constrained, return NULL_TREE. Note that T must be non-null. */
28499 tree
28501 {
28513 else
28515 }
28517 /* Associate the given constraint information CI with the declaration
28518 T. If T is a template, then the constraints are associated with
28519 its underlying declaration. Don't build associations if CI is
28520 NULL_TREE. */
28522 void
28524 {
28532 }
28534 /* Remove the associated constraints of the declaration T. */
28536 void
28538 {
28545 }
28547 static hashval_t
28549 {
28558 }
28560 /* Compare the constraints of two subsumption entries. The LEFT1 and
28561 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
28562 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
28564 static bool
28566 {
28574 }
28576 /* Key/value pair for learning and memoizing subsumption results. This
28577 associates a pair of check constraints (including arguments) with
28578 a boolean value indicating the result. */
28581 {
28582 tree t1;
28583 tree t2;
28585 };
28587 /* Hashing function and equality for constraint entries. */
28590 {
28592 {
28594 }
28597 {
28602 }
28603 };
28607 /* Search for a previously cached subsumption result. */
28611 {
28616 else
28618 }
28620 /* Save a subsumption result. */
28622 bool
28624 {
28631 }
28633 /* Set up the hash table for constraint association. */
28635 void
28637 {
28642 }
28646 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
28647 0..N-1. */
28649 void
28651 {
28654 integer_type_node,
28655 NULL_TREE),
28659 CP_BUILT_IN_INTEGER_PACK);
28660 }
28662 /* Set up the hash tables for template instantiations. */
28664 void
28666 {
28667 /* FIXME: enable sanitization (PR87847) */
28673 }
28675 /* Print stats about the template hash tables for -fstats. */
28677 void
28679 {
28688 }
28690 #if CHECKING_P
28694 /* Verify that build_non_dependent_expr () works, for various expressions,
28695 and that location wrappers don't affect the results. */
28697 static void
28699 {
28702 /* Verify constants, without and with location wrappers. */
28719 }
28721 /* Verify that type_dependent_expression_p () works correctly, even
28722 in the presence of location wrapper nodes. */
28724 static void
28726 {
28731 /* If no templates are involved, nothing is type-dependent. */
28737 /* Within a template, an unresolved name is always type-dependent. */
28740 /* Ensure it copes with NULL_TREE and errors. */
28744 /* A USING_DECL in a template should be type-dependent, even if wrapped
28745 with a location wrapper (PR c++/83799). */
28754 }
28756 /* Run all of the selftests within this file. */
28758 void
28760 {
28763 }