| blob | bb5908fb85319203e3f33677454a6b41d63e628a |
1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2018 Free Software Foundation, Inc.
3 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
4 Rewritten by Jason Merrill (jason@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Known bugs or deficiencies include:
24 all methods must be provided in header files; can't use a source
25 file that contains only the method templates and "just win". */
46 /* The type of functions taking a tree, and some additional data, and
47 returning an int. */
50 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
51 instantiations have been deferred, either because their definitions
52 were not yet available, or because we were putting off doing the work. */
56 };
71 /* Live only within one (recursive) call to tsubst_expr. We use
72 this to pass the statement expression node from the STMT_EXPR
73 to the EXPR_STMT that is its result. */
76 // -------------------------------------------------------------------------- //
77 // Local Specialization Stack
78 //
79 // Implementation of the RAII helper for creating new local
80 // specializations.
83 {
86 else
88 }
91 {
94 }
96 /* True if we've recursed into fn_type_unification too many times. */
100 {
101 tree tmpl;
102 tree args;
103 tree spec;
104 };
107 {
110 };
116 /* Contains canonical template parameter types. The vector is indexed by
117 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
118 TREE_LIST, whose TREE_VALUEs contain the canonical template
119 parameters of various types and levels. */
122 #define UNIFY_ALLOW_NONE 0
123 #define UNIFY_ALLOW_MORE_CV_QUAL 1
124 #define UNIFY_ALLOW_LESS_CV_QUAL 2
125 #define UNIFY_ALLOW_DERIVED 4
126 #define UNIFY_ALLOW_INTEGER 8
127 #define UNIFY_ALLOW_OUTER_LEVEL 16
128 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
129 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
132 tbr_incomplete_type,
133 tbr_ambiguous_baseclass,
134 tbr_success
135 };
158 tree);
215 location_t);
226 /* Make the current scope suitable for access checking when we are
227 processing T. T can be FUNCTION_DECL for instantiated function
228 template, VAR_DECL for static member variable, or TYPE_DECL for
229 alias template (needed by instantiate_decl). */
231 static void
233 {
241 else
245 {
246 saved_access_scope = tree_cons
249 }
250 }
252 /* Restore the scope set up by push_access_scope. T is the node we
253 are processing. */
255 static void
257 {
259 {
262 }
266 else
268 }
270 /* Do any processing required when DECL (a member template
271 declaration) is finished. Returns the TEMPLATE_DECL corresponding
272 to DECL, unless it is a specialization, in which case the DECL
273 itself is returned. */
275 tree
277 {
284 {
285 tree type;
293 {
297 }
299 }
303 {
305 {
308 }
309 else
311 }
312 else
316 }
318 /* Create a template info node. */
320 tree
322 {
327 }
329 /* Return the template info node corresponding to T, whatever T is. */
331 tree
333 {
355 }
357 /* Returns the template nesting level of the indicated class TYPE.
359 For example, in:
360 template <class T>
361 struct A
362 {
363 template <class U>
364 struct B {};
365 };
367 A<T>::B<U> has depth two, while A<T> has depth one.
368 Both A<T>::B<int> and A<int>::B<U> have depth one, if
369 they are instantiations, not specializations.
371 This function is guaranteed to return 0 if passed NULL_TREE so
372 that, for example, `template_class_depth (current_class_type)' is
373 always safe. */
375 int
377 {
381 {
392 else
394 }
397 }
399 /* Subroutine of maybe_begin_member_template_processing.
400 Returns true if processing DECL needs us to push template parms. */
402 static bool
404 {
410 }
412 /* Subroutine of maybe_begin_member_template_processing.
413 Push the template parms in PARMS, starting from LEVELS steps into the
414 chain, and ending at the beginning, since template parms are listed
415 innermost first. */
417 static void
419 {
427 current_template_parms
433 NULL);
435 {
444 {
451 /* Push the CONST_DECL. */
457 }
458 }
459 }
461 /* Restore the template parameter context for a member template, a
462 friend template defined in a class definition, or a non-template
463 member of template class. */
465 void
467 {
468 tree parms;
473 {
476 /* Disregard full specializations (c++/60999). */
479 }
482 {
487 {
490 }
493 }
495 /* Remember how many levels of template parameters we pushed so that
496 we can pop them later. */
498 }
500 /* Undo the effects of maybe_begin_member_template_processing. */
502 void
504 {
513 {
517 }
518 }
520 /* Return a new template argument vector which contains all of ARGS,
521 but has as its innermost set of arguments the EXTRA_ARGS. */
523 static tree
525 {
526 tree new_args;
544 }
546 /* Like add_to_template_args, but only the outermost ARGS are added to
547 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
548 (EXTRA_ARGS) levels are added. This function is used to combine
549 the template arguments from a partial instantiation with the
550 template arguments used to attain the full instantiation from the
551 partial instantiation. */
553 static tree
555 {
556 tree new_args;
558 /* If there are more levels of EXTRA_ARGS than there are ARGS,
559 something very fishy is going on. */
562 /* If *all* the new arguments will be the EXTRA_ARGS, just return
563 them. */
567 /* For the moment, we make ARGS look like it contains fewer levels. */
572 /* Now, we restore ARGS to its full dimensions. */
576 }
578 /* Return the N levels of innermost template arguments from the ARGS. */
580 tree
582 {
583 tree new_args;
589 /* If N is 1, just return the innermost set of template arguments. */
593 /* If we're not removing anything, just return the arguments we were
594 given. */
600 /* Make a new set of arguments, not containing the outer arguments. */
607 }
609 /* The inverse of get_innermost_template_args: Return all but the innermost
610 EXTRA_LEVELS levels of template arguments from the ARGS. */
612 static tree
614 {
615 tree new_args;
621 /* If N is 1, just return the outermost set of template arguments. */
625 /* If we're not removing anything, just return the arguments we were
626 given. */
631 /* Make a new set of arguments, not containing the inner arguments. */
638 }
640 /* We've got a template header coming up; push to a new level for storing
641 the parms. */
643 void
645 {
646 /* We use a non-tag-transparent scope here, which causes pushtag to
647 put tags in this scope, rather than in the enclosing class or
648 namespace scope. This is the right thing, since we want
649 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
650 global template class, push_template_decl handles putting the
651 TEMPLATE_DECL into top-level scope. For a nested template class,
652 e.g.:
654 template <class T> struct S1 {
655 template <class T> struct S2 {};
656 };
658 pushtag contains special code to insert the TEMPLATE_DECL for S2
659 at the right scope. */
665 /* Add a dummy parameter level while we process the parameter list. */
666 current_template_parms
669 current_template_parms);
670 }
672 /* This routine is called when a specialization is declared. If it is
673 invalid to declare a specialization here, an error is reported and
674 false is returned, otherwise this routine will return true. */
676 static bool
678 {
681 /* [temp.expl.spec]
683 An explicit specialization shall be declared in the namespace of
684 which the template is a member, or, for member templates, in the
685 namespace of which the enclosing class or enclosing class
686 template is a member. An explicit specialization of a member
687 function, member class or static data member of a class template
688 shall be declared in the namespace of which the class template
689 is a member. */
691 {
694 }
696 /* [temp.expl.spec]
698 In an explicit specialization declaration for a member of a class
699 template or a member template that appears in namespace scope,
700 the member template and some of its enclosing class templates may
701 remain unspecialized, except that the declaration shall not
702 explicitly specialize a class member template if its enclosing
703 class templates are not explicitly specialized as well. */
705 {
708 }
711 }
713 /* We've just seen template <>. */
715 bool
717 {
721 }
723 /* Called at then end of processing a declaration preceded by
724 template<>. */
726 void
728 {
731 }
733 /* Any template <>'s that we have seen thus far are not referring to a
734 function specialization. */
736 void
738 {
741 }
743 /* We've just seen a template header. If SPECIALIZATION is nonzero,
744 it was of the form template <>. */
746 static void
748 {
750 template_header_count++;
751 }
753 /* We're beginning an explicit instantiation. */
755 void
757 {
760 }
763 void
765 {
768 }
770 /* An explicit specialization or partial specialization of TMPL is being
771 declared. Check that the namespace in which the specialization is
772 occurring is permissible. Returns false iff it is invalid to
773 specialize TMPL in the current namespace. */
775 static bool
777 {
780 /* [tmpl.expl.spec]
782 An explicit specialization shall be declared in a namespace enclosing the
783 specialized template. An explicit specialization whose declarator-id is
784 not qualified shall be declared in the nearest enclosing namespace of the
785 template, or, if the namespace is inline (7.3.1), any namespace from its
786 enclosing namespace set. */
789 {
792 }
795 /* Same or enclosing namespace. */
797 else
798 {
804 }
805 }
807 /* SPEC is an explicit instantiation. Check that it is valid to
808 perform this explicit instantiation in the current namespace. */
810 static void
812 {
813 tree ns;
815 /* DR 275: An explicit instantiation shall appear in an enclosing
816 namespace of its template. */
822 }
824 // Returns the type of a template specialization only if that
825 // specialization needs to be defined. Otherwise (e.g., if the type has
826 // already been defined), the function returns NULL_TREE.
827 static tree
829 {
830 // An implicit instantiation of an incomplete type implies
831 // the definition of a new class template.
832 //
833 // template<typename T>
834 // struct S;
835 //
836 // template<typename T>
837 // struct S<T*>;
838 //
839 // Here, S<T*> is an implicit instantiation of S whose type
840 // is incomplete.
844 // It can also be the case that TYPE is a completed specialization.
845 // Continuing the previous example, suppose we also declare:
846 //
847 // template<typename T>
848 // requires Integral<T>
849 // struct S<T*>;
850 //
851 // Here, S<T*> refers to the specialization S<T*> defined
852 // above. However, we need to differentiate definitions because
853 // we intend to define a new partial specialization. In this case,
854 // we rely on the fact that the constraints are different for
855 // this declaration than that above.
856 //
857 // Note that we also get here for injected class names and
858 // late-parsed template definitions. We must ensure that we
859 // do not create new type declarations for those cases.
861 {
865 // If there are no template parameters, this cannot be a new
866 // partial template specializtion?
870 // The injected-class-name is not a new partial specialization.
874 // If the constraints are not the same as those of the primary
875 // then, we can probably create a new specialization.
879 {
883 }
885 // Also, if there's a pre-existing specialization with matching
886 // constraints, then this also isn't new.
889 {
897 }
899 // Create a new type node (and corresponding type decl)
900 // for the newly declared specialization.
905 /* We only need a separate type node for storing the definition of this
906 partial specialization; uses of S<T*> are unconstrained, so all are
907 equivalent. So keep TYPE_CANONICAL the same. */
910 // Build the corresponding type decl.
916 }
919 }
921 /* The TYPE is being declared. If it is a template type, that means it
922 is a partial specialization. Do appropriate error-checking. */
924 tree
926 {
927 tree context;
932 /* A lambda that appears in specialization context is not itself a
933 specialization. */
938 {
942 }
947 {
953 else
956 }
958 {
959 /* This is for ordinary explicit specialization and partial
960 specialization of a template class such as:
962 template <> class C<int>;
964 or:
966 template <class T> class C<T*>;
968 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
971 {
978 {
983 }
984 }
990 /* Trying to define a specialization either without a template<> header
991 or in an inappropriate place. We've already given an error, so just
992 bail now so we don't actually define the specialization. */
994 }
1000 {
1001 /* This is for an explicit specialization of member class
1002 template according to [temp.expl.spec/18]:
1004 template <> template <class U> class C<int>::D;
1006 The context `C<int>' must be an implicit instantiation.
1007 Otherwise this is just a member class template declared
1008 earlier like:
1010 template <> class C<int> { template <class U> class D; };
1011 template <> template <class U> class C<int>::D;
1013 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1014 while in the second case, `C<int>::D' is a primary template
1015 and `C<T>::D' may not exist. */
1019 {
1020 tree t;
1025 {
1030 }
1032 /* Check for invalid specialization after instantiation:
1034 template <> template <> class C<int>::D<int>;
1035 template <> template <class U> class C<int>::D; */
1039 {
1043 {
1044 /* We already have a full specialization of this partial
1045 instantiation, or a full specialization has been
1046 looked up but not instantiated. Reassign it to the
1047 new member specialization template. */
1048 spec_entry elt;
1060 spec_entry **slot
1065 }
1066 else
1067 /* But if we've had an implicit instantiation, that's a
1068 problem ([temp.expl.spec]/6). */
1071 }
1073 /* Mark TYPE as a specialization. And as a result, we only
1074 have one level of template argument for the innermost
1075 class template. */
1080 }
1081 }
1083 {
1084 /* Someday C++0x may allow for enum template specialization. */
1089 else
1090 {
1093 }
1094 }
1097 }
1099 /* Returns nonzero if we can optimize the retrieval of specializations
1100 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1101 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1105 {
1108 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1109 parameter. */
1111 /* The optimized lookup depends on the fact that the
1112 template arguments for the member function template apply
1113 purely to the containing class, which is not true if the
1114 containing class is an explicit or partial
1115 specialization. */
1119 /* It is possible to have a template that is not a member
1120 template and is not a member of a template class:
1122 template <typename T>
1123 struct S { friend A::f(); };
1125 Here, the friend function is a template, but the context does
1126 not have template information. The optimized lookup relies
1127 on having ARGS be the template arguments for both the class
1128 and the function template. */
1130 }
1132 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1133 gone through coerce_template_parms by now. */
1135 static void
1137 {
1140 {
1143 {
1150 /* Allow typedefs on the type of a non-type argument, since a
1152 else
1154 }
1155 }
1157 }
1159 /* Retrieve the specialization (in the sense of [temp.spec] - a
1160 specialization is either an instantiation or an explicit
1161 specialization) of TMPL for the given template ARGS. If there is
1162 no such specialization, return NULL_TREE. The ARGS are a vector of
1163 arguments, or a vector of vectors of arguments, in the case of
1164 templates with more than one level of parameters.
1166 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1167 then we search for a partial specialization matching ARGS. This
1168 parameter is ignored if TMPL is not a class template.
1170 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1171 result is a NONTYPE_ARGUMENT_PACK. */
1173 static tree
1175 {
1185 /* There should be as many levels of arguments as there are
1186 levels of parameters. */
1195 /* Lambda functions in templates aren't instantiated normally, but through
1196 tsubst_lambda_expr. */
1201 {
1202 /* The template arguments actually apply to the containing
1203 class. Find the class specialization with those
1204 arguments. */
1206 tree class_specialization
1211 /* Find the instance of TMPL. */
1214 {
1217 /* using-declarations can add base methods to the method vec,
1218 and we don't want those here. */
1221 }
1223 }
1224 else
1225 {
1227 spec_entry elt;
1236 else
1244 }
1247 }
1249 /* Like retrieve_specialization, but for local declarations. */
1251 tree
1253 {
1259 }
1261 /* Returns nonzero iff DECL is a specialization of TMPL. */
1263 int
1265 {
1266 tree t;
1269 {
1275 }
1276 else
1277 {
1286 }
1289 }
1291 /* Returns nonzero iff DECL is a specialization of friend declaration
1292 FRIEND_DECL according to [temp.friend]. */
1294 bool
1296 {
1303 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1304 of a template class, we want to check if DECL is a specialization
1305 if this. */
1309 {
1310 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1313 }
1318 /* There is nothing to do if this is not a template friend. */
1325 /* [temp.friend/6]
1326 A member of a class template may be declared to be a friend of a
1327 non-template class. In this case, the corresponding member of
1328 every specialization of the class template is a friend of the
1329 class granting friendship.
1331 For example, given a template friend declaration
1333 template <class T> friend void A<T>::f();
1335 the member function below is considered a friend
1337 template <> struct A<int> {
1338 void f();
1339 };
1341 For this type of template friend, TEMPLATE_DEPTH below will be
1342 nonzero. To determine if DECL is a friend of FRIEND, we first
1343 check if the enclosing class is a specialization of another. */
1350 {
1351 /* Next, we check the members themselves. In order to handle
1352 a few tricky cases, such as when FRIEND_DECL's are
1354 template <class T> friend void A<T>::g(T t);
1355 template <class T> template <T t> friend void A<T>::h();
1357 and DECL's are
1359 void A<int>::g(int);
1360 template <int> void A<int>::h();
1362 we need to figure out ARGS, the template arguments from
1363 the context of DECL. This is required for template substitution
1364 of `T' in the function parameter of `g' and template parameter
1365 of `h' in the above examples. Here ARGS corresponds to `int'. */
1372 {
1374 {
1377 else
1379 current_depth++;
1380 }
1382 }
1385 {
1387 tree friend_type;
1388 tree decl_type;
1389 tree friend_args_type;
1390 tree decl_args_type;
1392 /* Make sure that both DECL and FRIEND_DECL are templates or
1393 non-templates. */
1399 {
1400 /* If both are templates, check template parameter list. */
1401 tree friend_parms
1406 friend_parms))
1410 }
1411 else
1419 /* Check if return types match. */
1423 /* Check if function parameter types match, ignoring the
1424 `this' parameter. */
1433 }
1434 else
1435 {
1436 /* DECL is a TYPE_DECL */
1440 /* Make sure that both DECL and FRIEND_DECL are templates or
1441 non-templates. */
1442 is_template
1449 {
1450 tree friend_parms;
1451 /* If both are templates, check the name of the two
1452 TEMPLATE_DECL's first because is_friend didn't. */
1457 /* Now check template parameter list. */
1458 friend_parms
1461 return comp_template_parms
1463 friend_parms);
1464 }
1465 else
1468 }
1469 }
1471 }
1473 /* Register the specialization SPEC as a specialization of TMPL with
1474 the indicated ARGS. IS_FRIEND indicates whether the specialization
1475 is actually just a friend declaration. Returns SPEC, or an
1476 equivalent prior declaration, if available.
1478 We also store instantiations of field packs in the hash table, even
1479 though they are not themselves templates, to make lookup easier. */
1481 static tree
1483 hashval_t hash)
1484 {
1485 tree fn;
1487 spec_entry elt;
1495 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1496 register it; we want the corresponding TEMPLATE_DECL instead.
1497 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1498 the more obvious `uses_template_parms (spec)' to avoid problems
1499 with default function arguments. In particular, given
1500 something like this:
1502 template <class T> void f(T t1, T t = T())
1504 the default argument expression is not substituted for in an
1505 instantiation unless and until it is actually needed. */
1509 /* We don't put these specializations in the hash table, but we might
1510 want to give an error about a mismatch. */
1512 else
1513 {
1521 slot =
1525 else
1527 }
1529 /* We can sometimes try to re-register a specialization that we've
1530 already got. In particular, regenerate_decl_from_template calls
1531 duplicate_decls which will update the specialization list. But,
1532 we'll still get called again here anyhow. It's more convenient
1533 to simply allow this than to try to prevent it. */
1537 {
1539 {
1542 {
1544 fn);
1546 }
1547 else
1548 {
1549 tree clone;
1550 /* This situation should occur only if the first
1551 specialization is an implicit instantiation, the
1552 second is an explicit specialization, and the
1553 implicit instantiation has not yet been used. That
1554 situation can occur if we have implicitly
1555 instantiated a member function and then specialized
1556 it later.
1558 We can also wind up here if a friend declaration that
1559 looked like an instantiation turns out to be a
1560 specialization:
1562 template <class T> void foo(T);
1563 class S { friend void foo<>(int) };
1564 template <> void foo(int);
1566 We transform the existing DECL in place so that any
1567 pointers to it become pointers to the updated
1568 declaration.
1570 If there was a definition for the template, but not
1571 for the specialization, we want this to look as if
1572 there were no definition, and vice versa. */
1575 /* The call to duplicate_decls will have applied
1576 [temp.expl.spec]:
1578 An explicit specialization of a function template
1579 is inline only if it is explicitly declared to be,
1580 and independently of whether its function template
1581 is.
1583 to the primary function; now copy the inline bits to
1584 the various clones. */
1586 {
1593 }
1597 }
1598 }
1600 {
1603 /* We've already complained in duplicate_decls. */
1607 /* Dup decl failed, but this is a new definition. Set the
1608 line number so any errors match this new
1609 definition. */
1613 }
1614 }
1618 /* A specialization must be declared in the same namespace as the
1619 template it is specializing. */
1625 {
1634 /* If TMPL is a forward declaration of a template function, keep a list
1635 of all specializations in case we need to reassign them to a friend
1636 template later in tsubst_friend_function.
1638 Also keep a list of all variable template instantiations so that
1639 process_partial_specialization can check whether a later partial
1640 specialization would have used it. */
1643 }
1646 }
1648 /* Returns true iff two spec_entry nodes are equivalent. */
1652 bool
1654 {
1661 /* tmpl could be a FIELD_DECL for a capture pack. */
1665 {
1666 /* Partial specializations of a variable template can be distinguished by
1667 constraints. */
1671 }
1675 }
1677 /* Returns a hash for a template TMPL and template arguments ARGS. */
1679 static hashval_t
1681 {
1684 }
1686 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1687 ignoring SPEC. */
1689 hashval_t
1691 {
1693 }
1695 /* Recursively calculate a hash value for a template argument ARG, for use
1696 in the hash tables of template specializations. */
1698 hashval_t
1700 {
1720 {
1728 {
1733 }
1755 {
1759 {
1762 }
1764 }
1768 {
1771 }
1782 val = iterative_hash_template_arg
1794 val);
1796 val);
1805 /* A lambda can't appear in a template arg, but don't crash on
1806 erroneous input. */
1818 /* Now hash operands as usual. */
1823 }
1826 {
1829 {
1830 // We want an alias specialization that survived strip_typedefs
1831 // to hash differently from its TYPE_CANONICAL, to avoid hash
1832 // collisions that compare as different in template_args_equal.
1833 // These could be dependent specializations that strip_typedefs
1834 // left alone, or untouched specializations because
1835 // coerce_template_parms returns the unconverted template
1836 // arguments if it sees incomplete argument packs.
1839 }
1842 val);
1845 /* Otherwise just compare the types during lookup. */
1854 {
1859 }
1860 }
1863 }
1865 /* Unregister the specialization SPEC as a specialization of TMPL.
1866 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1867 if the SPEC was listed as a specialization of TMPL.
1869 Note that SPEC has been ggc_freed, so we can't look inside it. */
1871 bool
1873 {
1875 spec_entry elt;
1883 {
1888 }
1891 }
1893 /* Like register_specialization, but for local declarations. We are
1894 registering SPEC, an instantiation of TMPL. */
1896 void
1898 {
1901 }
1903 /* TYPE is a class type. Returns true if TYPE is an explicitly
1904 specialized class. */
1906 bool
1908 {
1912 }
1914 /* Print the list of functions at FNS, going through all the overloads
1915 for each element of the list. Alternatively, FNS can not be a
1916 TREE_LIST, in which case it will be printed together with all the
1917 overloads.
1919 MORE and *STR should respectively be FALSE and NULL when the function
1920 is called from the outside. They are used internally on recursive
1921 calls. print_candidates manages the two parameters and leaves NULL
1922 in *STR when it ends. */
1924 static void
1926 {
1930 else
1932 {
1938 {
1941 else
1944 }
1946 }
1947 }
1949 /* Print the list of candidate FNS in an error message. FNS can also
1950 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1952 void
1954 {
1958 }
1960 /* Get a (possibly) constrained template declaration for the
1961 purpose of ordering candidates. */
1962 static tree
1964 {
1970 }
1972 /* Among candidates having the same signature, return the
1973 most constrained or NULL_TREE if there is no best candidate.
1974 If the signatures of candidates vary (e.g., template
1975 specialization vs. member function), then there can be no
1976 most constrained.
1978 Note that we don't compare constraints on the functions
1979 themselves, but rather those of their templates. */
1980 static tree
1982 {
1983 // Try to find the best candidate in a first pass.
1986 {
1993 }
1995 // Verify that the champ is better than previous candidates.
2000 }
2003 }
2006 /* Returns the template (one of the functions given by TEMPLATE_ID)
2007 which can be specialized to match the indicated DECL with the
2008 explicit template args given in TEMPLATE_ID. The DECL may be
2009 NULL_TREE if none is available. In that case, the functions in
2010 TEMPLATE_ID are non-members.
2012 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2013 specialization of a member template.
2015 The TEMPLATE_COUNT is the number of references to qualifying
2016 template classes that appeared in the name of the function. See
2017 check_explicit_specialization for a more accurate description.
2019 TSK indicates what kind of template declaration (if any) is being
2020 declared. TSK_TEMPLATE indicates that the declaration given by
2021 DECL, though a FUNCTION_DECL, has template parameters, and is
2022 therefore a template function.
2024 The template args (those explicitly specified and those deduced)
2025 are output in a newly created vector *TARGS_OUT.
2027 If it is impossible to determine the result, an error message is
2028 issued. The error_mark_node is returned to indicate failure. */
2030 static tree
2032 tree decl,
2036 tmpl_spec_kind tsk)
2037 {
2038 tree fns;
2039 tree targs;
2040 tree explicit_targs;
2043 /* A TREE_LIST of templates of which DECL may be a specialization.
2044 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2045 corresponding TREE_PURPOSE is the set of template arguments that,
2046 when used to instantiate the template, would produce a function
2047 with the signature of DECL. */
2057 /* We shouldn't be specializing a member template of an
2058 unspecialized class template; we already gave an error in
2059 check_specialization_scope, now avoid crashing. */
2062 {
2065 }
2073 /* Check for baselinks. */
2078 {
2081 }
2083 {
2086 }
2088 /* Count the number of template headers specified for this
2089 specialization. */
2099 {
2102 tf_warning_or_error,
2106 }
2108 {
2112 {
2113 tree decl_arg_types;
2114 tree fn_arg_types;
2115 tree insttype;
2117 /* In case of explicit specialization, we need to check if
2118 the number of template headers appearing in the specialization
2119 is correct. This is usually done in check_explicit_specialization,
2120 but the check done there cannot be exhaustive when specializing
2121 member functions. Consider the following code:
2123 template <> void A<int>::f(int);
2124 template <> template <> void A<int>::f(int);
2126 Assuming that A<int> is not itself an explicit specialization
2127 already, the first line specializes "f" which is a non-template
2128 member function, whilst the second line specializes "f" which
2129 is a template member function. So both lines are syntactically
2130 correct, and check_explicit_specialization does not reject
2131 them.
2133 Here, we can do better, as we are matching the specialization
2134 against the declarations. We count the number of template
2135 headers, and we check if they match TEMPLATE_COUNT + 1
2136 (TEMPLATE_COUNT is the number of qualifying template classes,
2137 plus there must be another header for the member template
2138 itself).
2140 Notice that if header_count is zero, this is not a
2141 specialization but rather a template instantiation, so there
2142 is no check we can perform here. */
2146 /* Check that the number of template arguments at the
2147 innermost level for DECL is the same as for FN. */
2155 /* DECL might be a specialization of FN. */
2159 /* For a non-static member function, we need to make sure
2160 that the const qualification is the same. Since
2161 get_bindings does not try to merge the "this" parameter,
2162 we must do the comparison explicitly. */
2168 /* Skip the "this" parameter and, for constructors of
2169 classes with virtual bases, the VTT parameter. A
2170 full specialization of a constructor will have a VTT
2171 parameter, but a template never will. */
2172 decl_arg_types
2174 fn_arg_types
2177 /* Function templates cannot be specializations; there are
2178 no partial specializations of functions. Therefore, if
2179 the type of DECL does not match FN, there is no
2180 match.
2182 Note that it should never be the case that we have both
2183 candidates added here, and for regular member functions
2184 below. */
2186 {
2190 }
2192 /* See whether this function might be a specialization of this
2193 template. Suppress access control because we might be trying
2194 to make this specialization a friend, and we have already done
2195 access control for the declaration of the specialization. */
2201 /* We cannot deduce template arguments that when used to
2202 specialize TMPL will produce DECL. */
2205 /* Remove, from the set of candidates, all those functions
2206 whose constraints are not satisfied. */
2210 // Then, try to form the new function type.
2214 fn_arg_types
2219 /* Save this template, and the arguments deduced. */
2221 }
2223 /* FN is an ordinary member function, and we need a
2224 specialization of a member template. */
2225 ;
2227 /* We can get IDENTIFIER_NODEs here in certain erroneous
2228 cases. */
2229 ;
2231 /* This is just an ordinary non-member function. Nothing can
2232 be a specialization of that. */
2233 ;
2235 /* Cannot specialize functions that are created implicitly. */
2236 ;
2237 else
2238 {
2239 tree decl_arg_types;
2241 /* This is an ordinary member function. However, since
2242 we're here, we can assume its enclosing class is a
2243 template class. For example,
2245 template <typename T> struct S { void f(); };
2246 template <> void S<int>::f() {}
2248 Here, S<int>::f is a non-template, but S<int> is a
2249 template class. If FN has the same type as DECL, we
2250 might be in business. */
2253 /* Its enclosing class is an explicit specialization
2254 of a template class. This is not a candidate. */
2259 /* The return types differ. */
2262 /* Adjust the type of DECL in case FN is a static member. */
2269 decl_arg_types))
2272 // If the deduced arguments do not satisfy the constraints,
2273 // this is not a candidate.
2277 // Add the candidate.
2279 }
2280 }
2283 {
2284 /* We have:
2286 [temp.expl.spec]
2288 It is possible for a specialization with a given function
2289 signature to be instantiated from more than one function
2290 template. In such cases, explicit specification of the
2291 template arguments must be used to uniquely identify the
2292 function template specialization being specialized.
2294 Note that here, there's no suggestion that we're supposed to
2295 determine which of the candidate templates is most
2296 specialized. However, we, also have:
2298 [temp.func.order]
2300 Partial ordering of overloaded function template
2301 declarations is used in the following contexts to select
2302 the function template to which a function template
2303 specialization refers:
2305 -- when an explicit specialization refers to a function
2306 template.
2308 So, we do use the partial ordering rules, at least for now.
2309 This extension can only serve to make invalid programs valid,
2310 so it's safe. And, there is strong anecdotal evidence that
2311 the committee intended the partial ordering rules to apply;
2312 the EDG front end has that behavior, and John Spicer claims
2313 that the committee simply forgot to delete the wording in
2314 [temp.expl.spec]. */
2317 {
2320 }
2321 }
2323 // Concepts allows multiple declarations of member functions
2324 // with the same signature. Like above, we need to rely on
2325 // on the partial ordering of those candidates to determine which
2326 // is the best.
2328 {
2330 {
2333 }
2334 }
2337 {
2344 else
2347 }
2351 {
2357 }
2359 /* We have one, and exactly one, match. */
2361 {
2365 // Propagate the candidate's constraints to the declaration.
2368 /* DECL is a re-declaration or partial instantiation of a template
2369 function. */
2372 /* It was a specialization of an ordinary member function in a
2373 template class. */
2375 }
2377 /* It was a specialization of a template. */
2380 {
2385 }
2386 else
2389 }
2391 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2392 but with the default argument values filled in from those in the
2393 TMPL_TYPES. */
2395 static tree
2397 tree tmpl_types)
2398 {
2399 tree new_spec_types;
2407 /* Substitute into the rest of the list. */
2408 new_spec_types =
2412 /* Add the default argument for this parameter. */
2415 new_spec_types);
2416 }
2418 /* DECL is an explicit specialization. Replicate default arguments
2419 from the template it specializes. (That way, code like:
2421 template <class T> void f(T = 3);
2422 template <> void f(double);
2423 void g () { f (); }
2425 works, as required.) An alternative approach would be to look up
2426 the correct default arguments at the call-site, but this approach
2427 is consistent with how implicit instantiations are handled. */
2429 static void
2431 {
2432 tree tmpl;
2433 tree spec_types;
2434 tree tmpl_types;
2435 tree new_spec_types;
2436 tree old_type;
2437 tree new_type;
2438 tree t;
2443 /* See if there's anything we need to do. */
2456 {
2457 /* Remove the this pointer, but remember the object's type for
2458 CV quals. */
2464 {
2465 /* DECL may contain more parameters than TMPL due to the extra
2466 in-charge parameter in constructors and destructors. */
2469 }
2471 {
2474 }
2475 }
2477 /* Compute the merged default arguments. */
2478 new_spec_types =
2481 /* Compute the new FUNCTION_TYPE. */
2483 {
2487 new_spec_types);
2490 /* Put the in-charge parameter back. */
2493 new_spec_types);
2497 new_spec_types);
2498 }
2499 else
2501 new_spec_types);
2511 }
2513 /* Return the number of template headers we expect to see for a definition
2514 or specialization of CTYPE or one of its non-template members. */
2516 int
2518 {
2522 {
2523 /* You're supposed to have one `template <...>' for every
2524 template class, but you don't need one for a full
2525 specialization. For example:
2527 template <class T> struct S{};
2528 template <> struct S<int> { void f(); };
2529 void S<int>::f () {}
2531 is correct; there shouldn't be a `template <>' for the
2532 definition of `S<int>::f'. */
2534 /* If CTYPE does not have template information of any
2535 kind, then it is not a template, nor is it nested
2536 within a template. */
2544 }
2547 }
2549 /* Do a simple sanity check on the template headers that precede the
2550 variable declaration DECL. */
2552 void
2554 {
2559 {
2562 "variable templates only available with "
2565 // Namespace-scope variable templates should have a template header.
2567 }
2569 {
2571 "too many template headers for %qD "
2577 "members of an explicitly specialized class are defined "
2579 }
2580 }
2582 /* An explicit specialization whose declarator-id or class-head-name is not
2583 qualified shall be declared in the nearest enclosing namespace of the
2584 template, or, if the namespace is inline (7.3.1), any namespace from its
2585 enclosing namespace set.
2587 If the name declared in the explicit instantiation is an unqualified name,
2588 the explicit instantiation shall appear in the namespace where its template
2589 is declared or, if that namespace is inline (7.3.1), any namespace from its
2590 enclosing namespace set. */
2592 void
2594 {
2599 {
2605 /* This was allowed in C++98, so only pedwarn. */
2607 "outside its namespace must use a nested-name-"
2609 }
2610 }
2612 /* Check to see if the function just declared, as indicated in
2613 DECLARATOR, and in DECL, is a specialization of a function
2614 template. We may also discover that the declaration is an explicit
2615 instantiation at this point.
2617 Returns DECL, or an equivalent declaration that should be used
2618 instead if all goes well. Issues an error message if something is
2619 amiss. Returns error_mark_node if the error is not easily
2620 recoverable.
2622 FLAGS is a bitmask consisting of the following flags:
2624 2: The function has a definition.
2625 4: The function is a friend.
2627 The TEMPLATE_COUNT is the number of references to qualifying
2628 template classes that appeared in the name of the function. For
2629 example, in
2631 template <class T> struct S { void f(); };
2632 void S<int>::f();
2634 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2635 classes are not counted in the TEMPLATE_COUNT, so that in
2637 template <class T> struct S {};
2638 template <> struct S<int> { void f(); }
2639 template <> void S<int>::f();
2641 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2642 invalid; there should be no template <>.)
2644 If the function is a specialization, it is marked as such via
2645 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2646 is set up correctly, and it is added to the list of specializations
2647 for that template. */
2649 tree
2651 tree decl,
2654 {
2663 tmpl_spec_kind tsk;
2666 {
2669 else
2671 }
2672 else
2676 {
2679 {
2682 }
2684 {
2686 /* This could be something like:
2688 template <class T> void f(T);
2689 class S { friend void f<>(int); } */
2691 else
2692 {
2693 /* This case handles bogus declarations like template <>
2694 template <class T> void f<int>(); */
2697 declarator);
2699 }
2700 }
2704 /* The error has already been reported in
2705 check_specialization_scope. */
2711 /* Fall through. */
2724 decl);
2727 else
2731 /* Fall through. */
2737 /* In cases like template<> constexpr bool v = true;
2738 We'll give an error in check_template_variable. */
2744 else
2750 {
2751 /* This case handles bogus declarations like template <>
2752 template <class T> void f<int>(); */
2756 declarator);
2758 {
2759 /* Partial specialization of variable template. */
2763 }
2767 else
2771 ok:;
2772 }
2775 /* This is a specialization of a member template, without
2776 specialization the containing class. Something like:
2778 template <class T> struct S {
2779 template <class U> void f (U);
2780 };
2781 template <> template <class U> void S<int>::f(U) {}
2783 That's a specialization -- but of the entire template. */
2789 }
2792 /* This doesn't apply to variable templates. */
2795 {
2799 {
2803 }
2804 }
2807 {
2812 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2814 {
2815 tree fns;
2820 else
2821 {
2822 /* If there is no class context, the explicit instantiation
2823 must be at namespace scope. */
2826 /* Find the namespace binding, using the declaration
2827 context. */
2831 /* If lookup fails, look for a friend declaration so we can
2832 give a better diagnostic. */
2838 {
2841 }
2842 }
2845 }
2851 {
2853 /* A specialization in class scope. This is invalid,
2854 but the error will already have been flagged by
2855 check_specialization_scope. */
2857 else
2858 {
2859 /* It's not valid to write an explicit instantiation in
2860 class scope, e.g.:
2862 class C { template void f(); }
2864 This case is caught by the parser. However, on
2865 something like:
2867 template class C { void f(); };
2869 (which is invalid) we can get here. The error will be
2870 issued later. */
2871 ;
2872 }
2875 }
2878 {
2879 // We'll match variable templates in start_decl.
2883 /* Find the list of functions in ctype that have the same
2884 name as the declared function. */
2888 {
2892 {
2893 /* From [temp.expl.spec]:
2895 If such an explicit specialization for the member
2896 of a class template names an implicitly-declared
2897 special member function (clause _special_), the
2898 program is ill-formed.
2900 Similar language is found in [temp.explicit]. */
2903 }
2906 }
2908 /* For a type-conversion operator, We might be looking for
2909 `operator int' which will be a specialization of
2910 `operator T'. Grab all the conversion operators, and
2911 then select from them. */
2916 {
2919 }
2920 else
2922 }
2924 /* Figure out what exactly is being specialized at this point.
2925 Note that for an explicit instantiation, even one for a
2926 member function, we cannot tell a priori whether the
2927 instantiation is for a member template, or just a member
2928 function of a template class. Even if a member template is
2929 being instantiated, the member template arguments may be
2930 elided if they can be deduced from the rest of the
2931 declaration. */
2934 member_specialization,
2935 template_count,
2936 tsk);
2939 /* We couldn't figure out what this declaration was
2940 specializing. */
2942 else
2943 {
2946 {
2948 "friend declaration %qD is not visible to "
2952 }
2960 {
2961 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
2962 is done by do_decl_instantiation later. */
2968 {
2969 /* If TMPL is not the most general template (for
2970 example, if TMPL is a friend template that is
2971 injected into namespace scope), then there will
2972 be too many levels of TARGS. Remove some of them
2973 here. */
2975 tree new_targs;
2982 }
2985 }
2987 /* If we thought that the DECL was a member function, but it
2988 turns out to be specializing a static member function,
2989 make DECL a static member function as well. */
2995 /* If this is a specialization of a member template of a
2996 template class, we want to return the TEMPLATE_DECL, not
2997 the specialization of it. */
2999 {
3004 {
3005 tree parm;
3009 /* We want to use the argument list specified in the
3010 definition, not in the original declaration. */
3015 }
3018 }
3020 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3026 /* Inherit default function arguments from the template
3027 DECL is specializing. */
3031 /* This specialization has the same protection as the
3032 template it specializes. */
3036 /* 7.1.1-1 [dcl.stc]
3038 A storage-class-specifier shall not be specified in an
3039 explicit specialization...
3041 The parser rejects these, so unless action is taken here,
3042 explicit function specializations will always appear with
3043 global linkage.
3045 The action recommended by the C++ CWG in response to C++
3046 defect report 605 is to make the storage class and linkage
3047 of the explicit specialization match the templated function:
3049 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3050 */
3052 {
3056 /* A concept cannot be specialized. */
3058 {
3060 gen_tmpl);
3062 }
3064 /* This specialization has the same linkage and visibility as
3065 the function template it specializes. */
3068 {
3071 }
3074 {
3077 }
3078 }
3080 /* If DECL is a friend declaration, declared using an
3081 unqualified name, the namespace associated with DECL may
3082 have been set incorrectly. For example, in:
3084 template <typename T> void f(T);
3085 namespace N {
3086 struct S { friend void f<int>(int); }
3087 }
3089 we will have set the DECL_CONTEXT for the friend
3090 declaration to N, rather than to the global namespace. */
3095 /* This is not really a declaration of a specialization.
3096 It's just the name of an instantiation. But, it's not
3097 a request for an instantiation, either. */
3100 /* A specialization is not necessarily COMDAT. */
3106 /* If this is a full specialization, register it so that we can find
3107 it again. Partial specializations will be registered in
3108 process_partial_specialization. */
3113 /* A 'structor should already have clones. */
3119 }
3120 }
3123 }
3125 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3126 parameters. These are represented in the same format used for
3127 DECL_TEMPLATE_PARMS. */
3129 int
3131 {
3132 const_tree p1;
3133 const_tree p2;
3141 {
3153 {
3157 /* If either of the template parameters are invalid, assume
3158 they match for the sake of error recovery. */
3171 }
3172 }
3175 /* One set of parameters has more parameters lists than the
3176 other. */
3180 }
3182 /* Determine whether PARM is a parameter pack. */
3184 bool
3186 {
3187 /* Determine if we have a non-type template parameter pack. */
3194 /* If this is a list of template parameters, we could get a
3195 TYPE_DECL or a TEMPLATE_DECL. */
3199 /* Otherwise it must be a type template parameter. */
3203 }
3205 /* Determine if T is a function parameter pack. */
3207 bool
3209 {
3213 }
3215 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3216 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3218 tree
3220 {
3227 }
3229 /* Return true iff the function parameter PARAM_DECL was expanded
3230 from the function parameter pack PACK. */
3232 bool
3234 {
3239 /* The parameter pack and its pack arguments have the same
3240 DECL_PARM_INDEX. */
3242 }
3244 /* Determine whether ARGS describes a variadic template args list,
3245 i.e., one that is terminated by a template argument pack. */
3247 static bool
3249 {
3251 tree last_parm;
3265 }
3267 /* Generate a new name for the parameter pack name NAME (an
3268 IDENTIFIER_NODE) that incorporates its */
3270 static tree
3272 {
3273 /* Munge the name to include the parameter index. */
3274 #define NUMBUF_LEN 128
3288 }
3290 /* Return true if T is a primary function, class or alias template
3291 specialization, not including the template pattern. */
3293 bool
3295 {
3311 }
3313 /* Return true if PARM is a template template parameter. */
3315 bool
3317 {
3319 }
3321 /* Return true iff PARM is a DECL representing a type template
3322 parameter. */
3324 bool
3326 {
3331 }
3333 /* Return the template parameters of T if T is a
3334 primary template instantiation, NULL otherwise. */
3336 tree
3338 {
3343 parms = INNERMOST_TEMPLATE_PARMS
3347 }
3349 /* Return the template parameters of the LEVELth level from the full list
3350 of template parameters PARMS. */
3352 tree
3354 {
3355 tree p;
3366 }
3368 /* Returns the template arguments of T if T is a template instantiation,
3369 NULL otherwise. */
3371 tree
3373 {
3381 }
3383 /* Return the argument pack elements of T if T is a template argument pack,
3384 NULL otherwise. */
3386 tree
3388 {
3394 }
3396 /* True iff FN is a function representing a built-in variadic parameter
3397 pack. */
3399 bool
3401 {
3411 }
3413 /* True iff CALL is a call to a function representing a built-in variadic
3414 parameter pack. */
3416 static bool
3418 {
3422 }
3424 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3426 static tree
3428 tree in_decl)
3429 {
3435 {
3437 {
3440 }
3445 }
3446 else
3447 {
3451 /* Calculate the largest value of len that won't make the size of the vec
3452 overflow an int. The compiler will exceed resource limits long before
3453 this, but it seems a decent place to diagnose. */
3457 {
3462 }
3470 }
3471 }
3473 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3474 CALL. */
3476 static tree
3478 tree in_decl)
3479 {
3489 }
3491 /* Structure used to track the progress of find_parameter_packs_r. */
3492 struct find_parameter_pack_data
3493 {
3494 /* TREE_LIST that will contain all of the parameter packs found by
3495 the traversal. */
3498 /* Set of AST nodes that have been visited by the traversal. */
3501 /* True iff we're making a type pack expansion. */
3503 };
3505 /* Identifies all of the argument packs that occur in a template
3506 argument and appends them to the TREE_LIST inside DATA, which is a
3507 find_parameter_pack_data structure. This is a subroutine of
3508 make_pack_expansion and uses_parameter_packs. */
3509 static tree
3511 {
3517 /* Handle type aliases/typedefs. */
3519 {
3526 }
3528 /* Identify whether this is a parameter pack or not. */
3530 {
3538 /* FALLTHRU */
3540 /* If the placeholder appears in the decl-specifier-seq of a function
3541 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3542 is a pack expansion, the invented template parameter is a template
3543 parameter pack. */
3553 {
3554 /* We don't want to walk into the type of a PARM_DECL,
3555 because we don't want to see the type parameter pack. */
3558 }
3561 /* Look through a lambda capture proxy to the field pack. */
3564 {
3570 }
3572 {
3574 find_parameter_packs_r,
3577 }
3589 /* Not a parameter pack. */
3591 }
3594 {
3595 /* Add this parameter pack to the list. */
3597 }
3603 /* This switch statement will return immediately if we don't find a
3604 parameter pack. */
3606 {
3611 /* Check the template itself. */
3614 /* Check the template arguments. */
3628 /* Ignore the declaration of a capture proxy for a parameter pack. */
3636 /* Fall through. */
3681 {
3687 }
3690 {
3691 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3692 type_pack_expansion_p to false so that any placeholders
3693 within the expression don't get marked as parameter packs. */
3701 }
3705 }
3708 }
3710 /* Determines if the expression or type T uses any parameter packs. */
3711 bool
3713 {
3722 }
3724 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3725 representation a base-class initializer into a parameter pack
3726 expansion. If all goes well, the resulting node will be an
3727 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3728 respectively. */
3729 tree
3731 {
3732 tree result;
3741 {
3742 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3743 class initializer. In this case, the TREE_PURPOSE will be a
3744 _TYPE node (representing the base class expansion we're
3745 initializing) and the TREE_VALUE will be a TREE_LIST
3746 containing the initialization arguments.
3748 The resulting expansion looks somewhat different from most
3749 expansions. Rather than returning just one _EXPANSION, we
3750 return a TREE_LIST whose TREE_PURPOSE is a
3751 TYPE_PACK_EXPANSION containing the bases that will be
3752 initialized. The TREE_VALUE will be identical to the
3753 original TREE_VALUE, which is a list of arguments that will
3754 be passed to each base. We do not introduce any new pack
3755 expansion nodes into the TREE_VALUE (although it is possible
3756 that some already exist), because the TREE_PURPOSE and
3757 TREE_VALUE all need to be expanded together with the same
3758 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3759 resulting TREE_PURPOSE will mention the parameter packs in
3760 both the bases and the arguments to the bases. */
3761 tree purpose;
3762 tree value;
3765 /* Determine which parameter packs will be used by the base
3766 class expansion. */
3775 {
3778 arg);
3781 }
3784 {
3785 /* Collect the sets of parameter packs used in each of the
3786 initialization arguments. */
3788 {
3789 /* Determine which parameter packs will be expanded in this
3790 argument. */
3793 }
3794 }
3798 /* Create the pack expansion type for the base type. */
3804 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3805 they will rarely be compared to anything. */
3809 }
3814 /* Build the PACK_EXPANSION_* node. */
3815 result = for_types
3820 {
3821 /* Propagate type and const-expression information. */
3824 /* Mark this read now, since the expansion might be length 0. */
3826 }
3827 else
3828 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3829 they will rarely be compared to anything. */
3832 /* Determine which parameter packs will be expanded. */
3839 /* Make sure we found some parameter packs. */
3841 {
3843 {
3846 else
3848 }
3850 }
3856 }
3858 /* Checks T for any "bare" parameter packs, which have not yet been
3859 expanded, and issues an error if any are found. This operation can
3860 only be done on full expressions or types (e.g., an expression
3861 statement, "if" condition, etc.), because we could have expressions like:
3863 foo(f(g(h(args)))...)
3865 where "args" is a parameter pack. check_for_bare_parameter_packs
3866 should not be called for the subexpressions args, h(args),
3867 g(h(args)), or f(g(h(args))), because we would produce erroneous
3868 error messages.
3870 Returns TRUE and emits an error if there were bare parameter packs,
3871 returns FALSE otherwise. */
3872 bool
3874 {
3881 /* A lambda might use a parameter pack from the containing context. */
3895 {
3899 {
3910 else
3915 else
3919 }
3922 }
3925 }
3927 /* Expand any parameter packs that occur in the template arguments in
3928 ARGS. */
3929 tree
3931 {
3940 /* First, determine if we need to expand anything, and the number of
3941 slots we'll need. */
3943 {
3948 {
3952 else
3954 }
3955 else
3956 {
3958 num_result_args++;
3959 }
3960 }
3962 /* If no expansion is necessary, we're done. */
3966 /* Expand arguments. */
3969 non_default_args_count =
3972 {
3975 {
3982 }
3983 else
3984 {
3987 }
3988 }
3992 }
3994 /* Checks if DECL shadows a template parameter.
3996 [temp.local]: A template-parameter shall not be redeclared within its
3997 scope (including nested scopes).
3999 Emits an error and returns TRUE if the DECL shadows a parameter,
4000 returns FALSE otherwise. */
4002 bool
4004 {
4005 tree olddecl;
4007 /* If we're not in a template, we can't possibly shadow a template
4008 parameter. */
4012 /* Figure out what we're shadowing. */
4016 /* If there's no previous binding for this name, we're not shadowing
4017 anything, let alone a template parameter. */
4021 /* If we're not shadowing a template parameter, we're done. Note
4022 that OLDDECL might be an OVERLOAD (or perhaps even an
4023 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4024 node. */
4028 /* We check for decl != olddecl to avoid bogus errors for using a
4029 name inside a class. We check TPFI to avoid duplicate errors for
4030 inline member templates. */
4036 /* Don't complain about the injected class name, as we've already
4037 complained about the class itself. */
4044 else
4049 }
4051 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4052 ORIG_LEVEL, DECL, and TYPE. */
4054 static tree
4058 tree decl,
4059 tree type)
4060 {
4071 }
4073 /* Find the canonical type parameter for the given template type
4074 parameter. Returns the canonical type parameter, which may be TYPE
4075 if no such parameter existed. */
4077 static tree
4079 {
4080 tree list;
4094 else
4095 {
4099 }
4100 }
4102 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4103 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4104 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4105 new one is created. */
4107 static tree
4109 tsubst_flags_t complain)
4110 {
4115 {
4134 /* Template template parameters need this. */
4136 {
4143 }
4144 }
4147 }
4149 /* Process information from new template parameter PARM and append it
4150 to the LIST being built. This new parameter is a non-type
4151 parameter iff IS_NON_TYPE is true. This new parameter is a
4152 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4153 is in PARM_LOC. */
4155 tree
4158 {
4167 {
4171 {
4175 else
4177 }
4180 }
4183 {
4189 {
4190 /* [temp.param]
4192 The top-level cv-qualifiers on the template-parameter are
4193 ignored when determining its type. */
4198 && !is_parameter_pack
4199 /* If we're in a nested template parameter list, the template
4200 template parameter could be a parameter pack. */
4202 {
4203 /* This template parameter is not a parameter pack, but it
4204 should be. Complain about "bare" parameter packs. */
4207 /* Recover by calling this a parameter pack. */
4209 }
4210 }
4212 /* A template parameter is not modifiable. */
4221 processing_template_decl,
4226 }
4227 else
4228 {
4229 tree t;
4233 {
4235 /* This is for distinguishing between real templates and template
4236 template parameters */
4240 }
4241 else
4242 {
4244 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4247 }
4254 processing_template_decl,
4258 }
4262 /* Build requirements for the type/template parameter.
4263 This must be done after SET_DECL_TEMPLATE_PARM_P or
4264 process_template_parm could fail. */
4269 /* Build the parameter node linking the parameter declaration,
4270 its default argument (if any), and its constraints (if any). */
4275 }
4277 /* The end of a template parameter list has been reached. Process the
4278 tree list into a parameter vector, converting each parameter into a more
4279 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4280 as PARM_DECLs. */
4282 tree
4284 {
4289 /* Pop the dummy parameter level and add the real one. */
4292 current_template_parms
4297 {
4301 }
4306 }
4308 // Explicitly indicate the end of the template parameter list. We assume
4309 // that the current template parameters have been constructed and/or
4310 // managed explicitly, as when creating new template template parameters
4311 // from a shorthand constraint.
4312 void
4314 {
4316 }
4318 /* end_template_decl is called after a template declaration is seen. */
4320 void
4322 {
4328 /* This matches the pushlevel in begin_template_parm_list. */
4333 }
4335 /* Takes a TREE_LIST representing a template parameter and convert it
4336 into an argument suitable to be passed to the type substitution
4337 functions. Note that If the TREE_LIST contains an error_mark
4338 node, the returned argument is error_mark_node. */
4340 tree
4342 {
4355 {
4359 {
4360 /* Turn this argument into a TYPE_ARGUMENT_PACK
4361 with a single element, which expands T. */
4370 }
4371 }
4372 else
4373 {
4377 {
4378 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4379 with a single element, which expands T. */
4389 }
4390 else
4392 }
4394 }
4396 /* Given a single level of template parameters (a TREE_VEC), return it
4397 as a set of template arguments. */
4399 static tree
4401 {
4411 }
4413 /* Given a set of template parameters, return them as a set of template
4414 arguments. The template parameters are represented as a TREE_VEC, in
4415 the form documented in cp-tree.h for template arguments. */
4417 static tree
4419 {
4420 tree header;
4425 /* If there is only one level of template parameters, we do not
4426 create a TREE_VEC of TREE_VECs. Instead, we return a single
4427 TREE_VEC containing the arguments. */
4432 {
4437 else
4439 }
4442 }
4444 /* Within the declaration of a template, return the currently active
4445 template parameters as an argument TREE_VEC. */
4447 static tree
4449 {
4451 }
4453 /* Update the declared TYPE by doing any lookups which were thought to be
4454 dependent, but are not now that we know the SCOPE of the declarator. */
4456 tree
4458 {
4469 /* Don't bother building up the args in this case. */
4471 {
4472 /* tsubst in the args corresponding to the template parameters,
4473 including auto if present. Most things will be unchanged, but
4474 make_typename_type and tsubst_qualified_id will resolve
4475 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4478 tree pushed;
4480 {
4484 }
4489 }
4495 {
4498 else
4500 }
4502 }
4504 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4505 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4506 the new template is a member template. */
4508 tree
4510 {
4518 }
4520 struct template_parm_data
4521 {
4522 /* The level of the template parameters we are currently
4523 processing. */
4526 /* The index of the specialization argument we are currently
4527 processing. */
4530 /* An array whose size is the number of template parameters. The
4531 elements are nonzero if the parameter has been used in any one
4532 of the arguments processed so far. */
4535 /* An array whose size is the number of template arguments. The
4536 elements are nonzero if the argument makes use of template
4537 parameters of this level. */
4539 };
4541 /* Subroutine of push_template_decl used to see if each template
4542 parameter in a partial specialization is used in the explicit
4543 argument list. If T is of the LEVEL given in DATA (which is
4544 treated as a template_parm_data*), then DATA->PARMS is marked
4545 appropriately. */
4547 static int
4549 {
4557 {
4560 }
4562 /* In C++17 the type of a non-type argument is a deduced context. */
4567 data,
4568 NULL,
4571 /* Return zero so that for_each_template_parm will continue the
4572 traversal of the tree; we want to mark *every* template parm. */
4574 }
4576 /* Process the partial specialization DECL. */
4578 static tree
4580 {
4587 tree inner_parms;
4588 tree inst;
4598 /* A concept cannot be specialized. */
4600 {
4603 }
4608 /* We check that each of the template parameters given in the
4609 partial specialization is used in the argument list to the
4610 specialization. For example:
4612 template <class T> struct S;
4613 template <class T> struct S<T*>;
4615 The second declaration is OK because `T*' uses the template
4616 parameter T, whereas
4618 template <class T> struct S<int>;
4620 is no good. Even trickier is:
4622 template <class T>
4623 struct S1
4624 {
4625 template <class U>
4626 struct S2;
4627 template <class U>
4628 struct S2<T>;
4629 };
4631 The S2<T> declaration is actually invalid; it is a
4632 full-specialization. Of course,
4634 template <class U>
4635 struct S2<T (*)(U)>;
4637 or some such would have been OK. */
4645 {
4650 NULL,
4652 }
4655 {
4656 /* One of the template parms was not used in a deduced context in the
4657 specialization. */
4659 {
4663 }
4667 }
4672 /* [temp.class.spec]
4674 The argument list of the specialization shall not be identical to
4675 the implicit argument list of the primary template. */
4676 tree main_args
4679 && (!flag_concepts
4682 {
4686 else
4690 }
4692 /* A partial specialization that replaces multiple parameters of the
4693 primary template with a pack expansion is less specialized for those
4694 parameters. */
4696 {
4698 "primary template because it replaces multiple parameters "
4701 /* Avoid crash in process_partial_specialization. */
4703 }
4705 /* If we aren't in a dependent class, we can actually try deduction. */
4707 /* FIXME we should be able to handle a partial specialization of a
4708 partial instantiation, but currently we can't (c++/41727). */
4711 {
4715 maintmpl);
4716 }
4718 /* [temp.class.spec]
4720 A partially specialized non-type argument expression shall not
4721 involve template parameters of the partial specialization except
4722 when the argument expression is a simple identifier.
4724 The type of a template parameter corresponding to a specialized
4725 non-type argument shall not be dependent on a parameter of the
4726 specialization.
4728 Also, we verify that pack expansions only occur at the
4729 end of the argument list. */
4733 {
4740 {
4741 /* Extract the arguments from the argument pack. We'll be
4742 iterating over these in the following loop. */
4745 }
4748 {
4750 /* Get the Jth argument in the parameter pack. */
4754 {
4755 /* Pack expansions must come at the end of the
4756 argument list. */
4759 {
4763 else
4766 }
4767 }
4770 /* We only care about the pattern. */
4776 /* This next two lines are the `argument expression is not just a
4777 simple identifier' condition and also the `specialized
4778 non-type argument' bit. */
4782 {
4786 arg);
4787 else
4788 {
4789 /* Look at the corresponding template parameter,
4790 marking which template parameters its type depends
4791 upon. */
4795 {
4796 /* We haven't yet initialized TPD2. Do so now. */
4798 /* The number of parameters here is the number in the
4799 main template, which, as checked in the assertion
4800 above, is NARGS. */
4804 }
4806 /* Mark the template parameters. But this time, we're
4807 looking for the template parameters of the main
4808 template, not in the specialization. */
4815 NULL,
4819 {
4820 /* The type depended on some template parameters.
4821 If they are fully specialized in the
4822 specialization, that's OK. */
4831 "type %qT of template argument %qE depends "
4833 "type %qT of template argument %qE depends "
4835 type,
4836 arg);
4837 }
4838 }
4839 }
4840 }
4841 }
4843 /* We should only get here once. */
4847 // Build the template decl.
4856 /* Give template template parms a DECL_CONTEXT of the template
4857 for which they are a parameter. */
4859 {
4863 }
4866 /* We didn't register this in check_explicit_specialization so we could
4867 wait until the constraints were set. */
4869 else
4879 {
4885 {
4893 "declaration of %qD ambiguates earlier template "
4897 "partial specialization of %qD after instantiation "
4899 }
4900 }
4903 }
4905 /* PARM is a template parameter of some form; return the corresponding
4906 TEMPLATE_PARM_INDEX. */
4908 static tree
4910 {
4923 }
4925 /* Subroutine of fixed_parameter_pack_p below. Look for any template
4926 parameter packs used by the template parameter PARM. */
4928 static void
4930 {
4931 /* A type parm can't refer to another parm. */
4935 {
4939 }
4946 }
4948 /* PARM is a template parameter pack. Return any parameter packs used in
4949 its type or the type of any of its template parameters. If there are
4950 any such packs, it will be instantiated into a fixed template parameter
4951 list by partial instantiation rather than be fully deduced. */
4953 tree
4955 {
4956 /* This can only be true in a member template. */
4959 /* This can only be true for a parameter pack. */
4962 /* A type parm can't refer to another parm. */
4976 }
4978 /* Check that a template declaration's use of default arguments and
4979 parameter packs is not invalid. Here, PARMS are the template
4980 parameters. IS_PRIMARY is true if DECL is the thing declared by
4981 a primary template. IS_PARTIAL is true if DECL is a partial
4982 specialization.
4984 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
4985 function template declaration or a friend class template
4986 declaration. In the function case, 1 indicates a declaration, 2
4987 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4988 emitted for extraneous default arguments.
4990 Returns TRUE if there were no errors found, FALSE otherwise. */
4992 bool
4995 {
4998 tree parm_level;
5001 /* [temp.param]
5003 A default template-argument shall not be specified in a
5004 function template declaration or a function template definition, nor
5005 in the template-parameter-list of the definition of a member of a
5006 class template. */
5010 /* You can't have a function template declaration in a local
5011 scope, nor you can you define a member of a class template in a
5012 local scope. */
5020 /* A lambda doesn't have an explicit declaration; don't complain
5021 about the parms of the enclosing class. */
5028 /* If this is either a friend defined in the scope of the class
5029 or a member function. */
5035 /* And, if it was a member function, it really was defined in
5036 the scope of the class. */
5039 /* We already checked these parameters when the template was
5040 declared, so there's no need to do it again now. This function
5041 was defined in class scope, but we're processing its body now
5042 that the class is complete. */
5045 /* Core issue 226 (C++0x only): the following only applies to class
5046 templates. */
5049 {
5050 /* [temp.param]
5052 If a template-parameter has a default template-argument, all
5053 subsequent template-parameters shall have a default
5054 template-argument supplied. */
5056 {
5063 {
5073 {
5075 /* For better subsequent error-recovery, we indicate that
5076 there should have been a default argument. */
5079 }
5081 && !is_friend_decl
5082 /* Don't complain about an enclosing partial
5083 specialization. */
5088 /* A fixed parameter pack will be partially
5089 instantiated into a fixed length list. */
5091 {
5092 /* A primary class template can only have one
5093 parameter pack, at the end of the template
5094 parameter list. */
5102 }
5103 }
5104 }
5105 }
5108 || is_partial
5109 || !is_primary
5111 /* For an ordinary class template, default template arguments are
5112 allowed at the innermost level, e.g.:
5113 template <class T = int>
5114 struct S {};
5115 but, in a partial specialization, they're not allowed even
5116 there, as we have in [temp.class.spec]:
5118 The template parameter list of a specialization shall not
5119 contain default template argument values.
5121 So, for a partial specialization, or for a function template
5122 (in C++98/C++03), we look at all of them. */
5123 ;
5124 else
5125 /* But, for a primary class template that is not a partial
5126 specialization we look at all template parameters except the
5127 innermost ones. */
5130 /* Figure out what error message to issue. */
5145 else
5146 /* Per [temp.param]/9, "A default template-argument shall not be
5147 specified in the template-parameter-lists of the definition of
5148 a member of a class template that appears outside of the member's
5149 class.", thus if we aren't handling a member of a class template
5150 there is no need to examine the parameters. */
5154 /* If we're inside a class definition, there's no need to
5155 examine the parameters to the class itself. On the one
5156 hand, they will be checked when the class is defined, and,
5157 on the other, default arguments are valid in things like:
5158 template <class T = double>
5159 struct S { template <class U> void f(U); };
5160 Here the default argument for `S' has no bearing on the
5161 declaration of `f'. */
5163 else
5164 /* Check everything. */
5170 {
5177 {
5182 {
5184 {
5191 }
5193 /* Clear out the default argument so that we are not
5194 confused later. */
5196 }
5197 }
5199 /* At this point, if we're still interested in issuing messages,
5200 they must apply to classes surrounding the object declared. */
5204 }
5207 }
5209 /* Worker for push_template_decl_real, called via
5210 for_each_template_parm. DATA is really an int, indicating the
5211 level of the parameters we are interested in. If T is a template
5212 parameter of that level, return nonzero. */
5214 static int
5216 {
5222 else
5225 }
5227 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5228 DATA is really an int, indicating the innermost outer level of parameters.
5229 If T is a template parameter of that level or further out, return
5230 nonzero. */
5232 static int
5234 {
5240 else
5243 }
5245 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5246 parameters given by current_template_args, or reuses a
5247 previously existing one, if appropriate. Returns the DECL, or an
5248 equivalent one, if it is replaced via a call to duplicate_decls.
5250 If IS_FRIEND is true, DECL is a friend declaration. */
5252 tree
5254 {
5255 tree tmpl;
5256 tree args;
5257 tree info;
5258 tree ctx;
5262 /* True if the template is a member template, in the sense of
5263 [temp.mem]. */
5269 /* See if this is a partial specialization. */
5282 /* For a friend, we want the context of the friend, not
5283 the type of which it is a friend. */
5287 /* In the case of a virtual function, we want the class in which
5288 it is defined. */
5290 else
5291 /* Otherwise, if we're currently defining some class, the DECL
5292 is assumed to be a member of the class. */
5301 /* See if this is a primary template. */
5304 /* A friend template that specifies a class context, i.e.
5305 template <typename T> friend void A<T>::f();
5306 is not primary. */
5311 else
5315 {
5322 {
5325 }
5327 {
5329 {
5332 }
5334 {
5335 /* [temp.mem]
5337 A destructor shall not be a member template. */
5340 }
5347 {
5348 /* [basic.stc.dynamic.allocation]
5350 An allocation function can be a function
5351 template. ... Template allocation functions shall
5352 have two or more parameters. */
5355 }
5356 }
5359 {
5360 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5363 {
5369 }
5370 }
5373 /* alias-declaration */
5377 else
5378 {
5381 }
5382 }
5384 /* Check to see that the rules regarding the use of default
5385 arguments are not being violated. We check args for a friend
5386 functions when we know whether it's a definition, introducing
5387 declaration or re-declaration. */
5392 /* Ensure that there are no parameter packs in the type of this
5393 declaration that have not been expanded. */
5395 {
5396 /* Check each of the arguments individually to see if there are
5397 any bare parameter packs. */
5403 {
5406 {
5407 /* This is a PARM_DECL that contains unexpanded parameter
5408 packs. We have already complained about this in the
5409 check_for_bare_parameter_packs call, so just replace
5410 these types with ERROR_MARK_NODE. */
5413 }
5417 }
5419 /* Check for bare parameter packs in the return type and the
5420 exception specifiers. */
5422 /* Errors were already issued, set return type to int
5423 as the frontend doesn't expect error_mark_node as
5424 the return type. */
5428 }
5433 {
5436 }
5449 {
5454 /* If DECL is a TYPE_DECL for a class-template, then there won't
5455 be DECL_LANG_SPECIFIC. The information equivalent to
5456 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5460 {
5461 /* Since a template declaration already existed for this
5462 class-type, we must be redeclaring it here. Make sure
5463 that the redeclaration is valid. */
5465 current_template_parms,
5467 /* We don't need to create a new TEMPLATE_DECL; just use the
5468 one we already had. */
5470 }
5471 else
5472 {
5474 member_template_p);
5479 {
5480 /* A specialization of a member template of a template
5481 class. */
5485 }
5486 }
5487 }
5488 else
5489 {
5495 {
5498 }
5506 {
5507 tree new_tmpl;
5509 /* The declaration is a specialization of a member
5510 template, declared outside the class. Therefore, the
5511 innermost template arguments will be NULL, so we
5512 replace them with the arguments determined by the
5513 earlier call to check_explicit_specialization. */
5516 new_tmpl
5518 member_template_p);
5528 args,
5531 }
5533 /* Make sure the template headers we got make sense. */
5538 {
5543 }
5544 else
5546 {
5551 {
5555 else
5559 /* Avoid crash in import_export_decl. */
5562 }
5567 /* Can happen in erroneous input. */
5569 else
5571 }
5573 /* Check that the parms are used in the appropriate qualifying scopes
5574 in the declarator. */
5578 {
5584 /* Avoid crash in import_export_decl. */
5587 }
5588 }
5593 /* Push template declarations for global functions and types. Note
5594 that we do not try to push a global template friend declared in a
5595 template class; such a thing may well depend on the template
5596 parameters of the class. */
5599 {
5604 /* Hide template friend classes that haven't been declared yet. */
5606 {
5609 }
5610 }
5613 {
5618 /* Give template template parms a DECL_CONTEXT of the template
5619 for which they are a parameter. */
5622 {
5626 }
5632 }
5634 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5635 back to its most general template. If TMPL is a specialization,
5636 ARGS may only have the innermost set of arguments. Add the missing
5637 argument levels if necessary. */
5645 else
5646 {
5651 }
5654 && !is_friend
5657 /* Set DECL_COMDAT on template instantiations; if we force
5658 them to be emitted by explicit instantiation or -frepo,
5659 mark_needed will tell cgraph to do the right thing. */
5663 }
5665 tree
5667 {
5669 }
5671 /* FN is an inheriting constructor that inherits from the constructor
5672 template INHERITED; turn FN into a constructor template with a matching
5673 template header. */
5675 tree
5677 {
5678 tree inner_parms
5681 tree parms
5692 }
5694 /* Called when a class template TYPE is redeclared with the indicated
5695 template PARMS, e.g.:
5697 template <class T> struct S;
5698 template <class T> struct S {}; */
5700 bool
5702 {
5703 tree tmpl;
5704 tree tmpl_parms;
5708 {
5711 }
5715 /* The type is nested in some template class. Nothing to worry
5716 about here; there are no new template parameters for the nested
5717 type. */
5721 {
5723 tmpl);
5725 }
5731 {
5741 }
5744 {
5745 tree tmpl_parm;
5746 tree parm;
5747 tree tmpl_default;
5748 tree parm_default;
5762 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5763 TEMPLATE_DECL. */
5773 {
5777 }
5780 {
5781 /* We have in [temp.param]:
5783 A template-parameter may not be given default arguments
5784 by two different declarations in the same scope. */
5789 }
5792 /* Update the previous template parameters (which are the ones
5793 that will really count) with the new default value. */
5796 /* Update the new parameters, too; they'll be used as the
5797 parameters for any members. */
5800 /* Give each template template parm in this redeclaration a
5801 DECL_CONTEXT of the template for which they are a parameter. */
5803 {
5806 }
5810 }
5812 // Cannot redeclare a class template with a different set of constraints.
5814 {
5819 }
5822 }
5824 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5825 to be used when the caller has already checked
5826 (processing_template_decl
5827 && !instantiation_dependent_expression_p (expr)
5828 && potential_constant_expression (expr))
5829 and cleared processing_template_decl. */
5831 tree
5833 {
5836 complain,
5840 }
5842 /* Simplify EXPR if it is a non-dependent expression. Returns the
5843 (possibly simplified) expression. */
5845 tree
5847 {
5851 /* If we're in a template, but EXPR isn't value dependent, simplify
5852 it. We're supposed to treat:
5854 template <typename T> void f(T[1 + 1]);
5855 template <typename T> void f(T[2]);
5857 as two declarations of the same function, for example. */
5860 {
5861 processing_template_decl_sentinel s;
5863 }
5865 }
5867 tree
5869 {
5871 }
5873 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
5874 an uninstantiated expression. */
5876 tree
5878 {
5882 {
5885 else
5886 {
5887 processing_template_decl_sentinel s;
5889 }
5890 }
5892 }
5894 /* True iff T is a specialization of a variable template. */
5896 bool
5898 {
5903 }
5905 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5906 template declaration, or a TYPE_DECL for an alias declaration. */
5908 bool
5910 {
5918 }
5920 /* Return TRUE iff T is a specialization of an alias template. */
5922 bool
5924 {
5925 /* It's an alias template specialization if it's an alias and its
5926 TYPE_NAME is a specialization of a primary template. */
5932 }
5934 /* An alias template is complex from a SFINAE perspective if a template-id
5935 using that alias can be ill-formed when the expansion is not, as with
5936 the void_t template. We determine this by checking whether the
5937 expansion for the alias template uses all its template parameters. */
5939 struct uses_all_template_parms_data
5940 {
5943 };
5945 static int
5947 {
5955 }
5957 static bool
5959 {
5974 }
5976 /* Return TRUE iff T is a specialization of a complex alias template with
5977 dependent template-arguments. */
5979 bool
5981 {
5994 }
5996 /* Return the number of innermost template parameters in TMPL. */
5998 static int
6000 {
6003 }
6005 /* Return either TMPL or another template that it is equivalent to under DR
6006 1286: An alias that just changes the name of a template is equivalent to
6007 the other template. */
6009 static tree
6011 {
6014 {
6015 /* Determine if the alias is equivalent to an underlying template. */
6027 tree alias_args = INNERMOST_TEMPLATE_ARGS
6032 /* Alias is equivalent. Strip it and repeat. */
6034 }
6037 }
6039 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6040 must be a reference-to-function or a pointer-to-function type, as specified
6041 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6042 and check that the resulting function has external linkage. */
6044 static tree
6046 tsubst_flags_t complain)
6047 {
6050 linkage_kind linkage;
6065 /* [temp.arg.nontype]/1
6067 A template-argument for a non-type, non-template template-parameter
6068 shall be one of:
6069 [...]
6070 -- the address of an object or function with external [C++11: or
6071 internal] linkage. */
6074 {
6076 {
6082 else
6085 }
6087 }
6091 {
6093 {
6098 else
6102 }
6104 }
6106 accept:
6113 }
6115 /* Subroutine of convert_nontype_argument.
6116 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6117 Emit an error otherwise. */
6119 static bool
6121 tsubst_flags_t complain)
6122 {
6139 {
6144 else
6146 }
6148 }
6150 /* Returns TRUE iff the address of OP is value-dependent.
6152 14.6.2.4 [temp.dep.temp]:
6153 A non-integral non-type template-argument is dependent if its type is
6154 dependent or it has either of the following forms
6155 qualified-id
6156 & qualified-id
6157 and contains a nested-name-specifier which specifies a class-name that
6158 names a dependent type.
6160 We generalize this to just say that the address of a member of a
6161 dependent class is value-dependent; the above doesn't cover the
6162 address of a static data member named with an unqualified-id. */
6164 static bool
6166 {
6167 /* We could use get_inner_reference here, but there's no need;
6168 this is only relevant for template non-type arguments, which
6169 can only be expressed as &id-expression. */
6171 {
6175 }
6178 }
6180 /* The next set of functions are used for providing helpful explanatory
6181 diagnostics for failed overload resolution. Their messages should be
6182 indented by two spaces for consistency with the messages in
6183 call.c */
6185 static int
6187 {
6189 }
6191 /* Other failure functions should call this one, to provide a single function
6192 for setting a breakpoint on. */
6194 static int
6196 {
6198 }
6200 static int
6202 {
6207 }
6209 static int
6211 {
6217 }
6219 static int
6221 {
6225 }
6227 static int
6229 {
6232 " template parameter %qD is not a parameter pack, but "
6236 }
6238 static int
6240 {
6243 " template argument %qE does not match "
6247 }
6249 static int
6251 {
6255 }
6257 static int
6259 {
6265 }
6267 static int
6269 {
6271 {
6276 else
6278 " deduced conflicting values for non-type parameter "
6280 }
6282 }
6284 static int
6286 {
6289 " variable-sized array type %qT is not "
6291 arg);
6293 }
6295 static int
6297 {
6301 arg);
6303 }
6305 static int
6307 {
6309 {
6315 else
6320 }
6322 }
6324 static int
6326 {
6328 }
6330 static int
6333 {
6335 }
6337 static int
6340 {
6346 }
6348 static int
6351 {
6354 {
6362 }
6364 }
6366 static int
6368 {
6371 " template parameters of a template template argument are "
6374 }
6376 static int
6378 {
6384 }
6386 static int
6388 {
6393 }
6395 /* Attempt to convert the non-type template parameter EXPR to the
6396 indicated TYPE. If the conversion is successful, return the
6397 converted value. If the conversion is unsuccessful, return
6398 NULL_TREE if we issued an error message, or error_mark_node if we
6399 did not. We issue error messages for out-and-out bad template
6400 parameters, but not simply because the conversion failed, since we
6401 might be just trying to do argument deduction. Both TYPE and EXPR
6402 must be non-dependent.
6404 The conversion follows the special rules described in
6405 [temp.arg.nontype], and it is much more strict than an implicit
6406 conversion.
6408 This function is called twice for each template argument (see
6409 lookup_template_class for a more accurate description of this
6410 problem). This means that we need to handle expressions which
6411 are not valid in a C++ source, but can be created from the
6412 first call (for instance, casts to perform conversions). These
6413 hacks can go away after we fix the double coercion problem. */
6415 static tree
6417 {
6418 tree expr_type;
6422 /* Detect immediately string literals as invalid non-type argument.
6423 This special-case is not needed for correctness (we would easily
6424 catch this later), but only to provide better diagnostic for this
6425 common user mistake. As suggested by DR 100, we do not mention
6426 linkage issues in the diagnostic as this is not the point. */
6427 /* FIXME we're making this OK. */
6429 {
6435 }
6437 /* Add the ADDR_EXPR now for the benefit of
6438 value_dependent_expression_p. */
6441 {
6445 }
6447 /* If we are in a template, EXPR may be non-dependent, but still
6448 have a syntactic, rather than semantic, form. For example, EXPR
6449 might be a SCOPE_REF, rather than the VAR_DECL to which the
6450 SCOPE_REF refers. Preserving the qualifying scope is necessary
6451 so that access checking can be performed when the template is
6452 instantiated -- but here we need the resolved form so that we can
6453 convert the argument. */
6465 /* If the argument is non-dependent, perform any conversions in
6466 non-dependent context as well. */
6474 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6475 to a non-type argument of "nullptr". */
6479 /* In C++11, integral or enumeration non-type template arguments can be
6480 arbitrary constant expressions. Pointer and pointer to
6481 member arguments can be general constant expressions that evaluate
6482 to a null value, but otherwise still need to be of a specific form. */
6484 {
6486 /* A PTRMEM_CST is already constant, and a valid template
6487 argument for a parameter of pointer to member type, we just want
6488 to leave it in that form rather than lower it to a
6492 {
6493 /* C++17: A template-argument for a non-type template-parameter shall
6494 be a converted constant expression (8.20) of the type of the
6495 template-parameter. */
6501 }
6503 {
6508 }
6509 }
6513 else
6516 /* HACK: Due to double coercion, we can get a
6517 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6518 which is the tree that we built on the first call (see
6519 below when coercing to reference to object or to reference to
6520 function). We just strip everything and get to the arg.
6521 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6522 for examples. */
6524 {
6530 {
6531 /* ??? Maybe we could use convert_from_reference here, but we
6532 would need to relax its constraints because the NOP_EXPR
6533 could actually change the type to something more cv-qualified,
6534 and this is not folded by convert_from_reference. */
6539 && (same_type_ignoring_top_level_qualifiers_p
6542 {
6545 }
6546 }
6547 }
6549 /* [temp.arg.nontype]/5, bullet 1
6551 For a non-type template-parameter of integral or enumeration type,
6552 integral promotions (_conv.prom_) and integral conversions
6553 (_conv.integral_) are applied. */
6555 {
6557 {
6562 }
6567 /* Notice that there are constant expressions like '4 % 0' which
6568 do not fold into integer constants. */
6571 {
6573 {
6577 else
6583 /* else cxx_constant_value complained but gave us
6584 a real constant, so go ahead. */
6586 {
6587 /* Some assemble time constant expressions like
6588 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
6589 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
6590 as we can emit them into .rodata initializers of
6591 variables, yet they can't fold into an INTEGER_CST at
6592 compile time. Refuse them here. */
6597 }
6598 }
6599 else
6601 }
6603 /* Avoid typedef problems. */
6606 }
6607 /* [temp.arg.nontype]/5, bullet 2
6609 For a non-type template-parameter of type pointer to object,
6610 qualification conversions (_conv.qual_) and the array-to-pointer
6611 conversion (_conv.array_) are applied. */
6613 {
6616 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
6617 decay_conversion or an explicit cast. If it's a problematic cast,
6618 we'll complain about it below. */
6620 {
6625 {
6628 }
6629 }
6631 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6633 A template-argument for a non-type, non-template template-parameter
6634 shall be one of: [...]
6636 -- the name of a non-type template-parameter;
6637 -- the address of an object or function with external linkage, [...]
6638 expressed as "& id-expression" where the & is optional if the name
6639 refers to a function or array, or if the corresponding
6640 template-parameter is a reference.
6642 Here, we do not care about functions, as they are invalid anyway
6643 for a parameter of type pointer-to-object. */
6646 /* Non-type template parameters are OK. */
6647 ;
6651 {
6653 {
6656 "because %qD is a variable, not the address of "
6659 }
6661 {
6667 }
6668 /* Other values, like integer constants, might be valid
6669 non-type arguments of some other type. */
6671 }
6672 else
6673 {
6677 {
6682 }
6684 {
6690 }
6693 {
6698 }
6699 /* C++17: For a non-type template-parameter of reference or pointer
6700 type, the value of the constant expression shall not refer to (or
6701 for a pointer type, shall not be the address of):
6702 * a subobject (4.5),
6703 * a temporary object (15.2),
6704 * a string literal (5.13.5),
6705 * the result of a typeid expression (8.2.8), or
6706 * a predefined __func__ variable (11.4.1). */
6708 {
6711 decl);
6713 }
6717 {
6722 }
6724 {
6728 decl);
6730 }
6731 }
6738 }
6739 /* [temp.arg.nontype]/5, bullet 3
6741 For a non-type template-parameter of type reference to object, no
6742 conversions apply. The type referred to by the reference may be more
6743 cv-qualified than the (otherwise identical) type of the
6744 template-argument. The template-parameter is bound directly to the
6745 template-argument, which must be an lvalue. */
6747 {
6749 expr_type))
6753 {
6758 }
6761 {
6766 }
6768 /* [temp.arg.nontype]/1
6770 A template-argument for a non-type, non-template template-parameter
6771 shall be one of: [...]
6773 -- the address of an object or function with external linkage. */
6776 {
6779 {
6782 "because a reference variable does not have a constant "
6785 }
6786 }
6790 /* OK, dependent reference. We don't want to ask whether a DECL is
6792 else
6793 {
6795 {
6801 }
6803 /* DR 1155 allows internal linkage in C++11 and up. */
6806 {
6812 }
6815 }
6819 }
6820 /* [temp.arg.nontype]/5, bullet 4
6822 For a non-type template-parameter of type pointer to function, only
6823 the function-to-pointer conversion (_conv.func_) is applied. If the
6824 template-argument represents a set of overloaded functions (or a
6825 pointer to such), the matching function is selected from the set
6826 (_over.over_). */
6828 {
6829 /* If the argument is a template-id, we might not have enough
6830 context information to decay the pointer. */
6832 {
6836 }
6839 /* Null pointer values are OK in C++11. */
6845 }
6846 /* [temp.arg.nontype]/5, bullet 5
6848 For a non-type template-parameter of type reference to function, no
6849 conversions apply. If the template-argument represents a set of
6850 overloaded functions, the matching function is selected from the set
6851 (_over.over_). */
6853 {
6855 {
6857 {
6862 }
6864 }
6869 }
6870 /* [temp.arg.nontype]/5, bullet 6
6872 For a non-type template-parameter of type pointer to member function,
6873 no conversions apply. If the template-argument represents a set of
6874 overloaded member functions, the matching member function is selected
6875 from the set (_over.over_). */
6877 {
6882 /* [temp.arg.nontype] bullet 1 says the pointer to member
6883 expression must be a pointer-to-member constant. */
6888 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
6889 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
6892 }
6893 /* [temp.arg.nontype]/5, bullet 7
6895 For a non-type template-parameter of type pointer to data member,
6896 qualification conversions (_conv.qual_) are applied. */
6898 {
6899 /* [temp.arg.nontype] bullet 1 says the pointer to member
6900 expression must be a pointer-to-member constant. */
6908 }
6910 {
6912 {
6917 }
6919 }
6920 /* A template non-type parameter must be one of the above. */
6921 else
6924 /* Sanity check: did we actually convert the argument to the
6925 right type? */
6929 }
6931 /* Subroutine of coerce_template_template_parms, which returns 1 if
6932 PARM_PARM and ARG_PARM match using the rule for the template
6933 parameters of template template parameters. Both PARM and ARG are
6934 template parameters; the rest of the arguments are the same as for
6935 coerce_template_template_parms.
6936 */
6937 static int
6939 tree arg,
6940 tsubst_flags_t complain,
6941 tree in_decl,
6942 tree outer_args)
6943 {
6952 {
6954 /* We encounter instantiations of templates like
6955 template <template <template <class> class> class TT>
6956 class C; */
6957 {
6964 }
6965 /* Fall through. */
6970 /* Argument is a parameter pack but parameter is not. */
6975 /* The tsubst call is used to handle cases such as
6977 template <int> class C {};
6978 template <class T, template <T> class TT> class D {};
6979 D<int, C> d;
6981 i.e. the parameter list of TT depends on earlier parameters. */
6983 {
6988 }
6992 /* Argument is a parameter pack but parameter is not. */
6999 }
7002 }
7004 /* Coerce template argument list ARGLIST for use with template
7005 template-parameter TEMPL. */
7007 static tree
7009 tsubst_flags_t complain)
7010 {
7011 /* Consider an example where a template template parameter declared as
7013 template <class T, class U = std::allocator<T> > class TT
7015 The template parameter level of T and U are one level larger than
7016 of TT. To proper process the default argument of U, say when an
7017 instantiation `TT<int>' is seen, we need to build the full
7018 arguments containing {int} as the innermost level. Outer levels,
7019 available when not appearing as default template argument, can be
7020 obtained from the arguments of the enclosing template.
7022 Suppose that TT is later substituted with std::vector. The above
7023 instantiation is `TT<int, std::allocator<T> >' with TT at
7024 level 1, and T at level 2, while the template arguments at level 1
7025 becomes {std::vector} and the inner level 2 is {int}. */
7029 {
7031 /* We want arguments for the partial specialization, not arguments for
7032 the primary template. */
7034 else
7036 }
7038 {
7039 /* This is an argument of the current template, so we haven't set
7040 DECL_CONTEXT yet. */
7041 tree relevant_template_parms;
7043 /* Parameter levels that are greater than the level of the given
7044 template template parm are irrelevant. */
7051 }
7058 complain,
7061 }
7063 /* A cache of template template parameters with match-all default
7064 arguments. */
7066 static void
7068 {
7072 }
7073 static tree
7075 {
7080 }
7082 /* T is a bound template template-parameter. Copy its arguments into default
7083 arguments of the template template-parameter's template parameters. */
7085 static tree
7087 {
7110 {
7113 {
7116 }
7117 }
7121 }
7123 /* ARG is a bound potential template template-argument, and PARGS is a list
7124 of arguments for the corresponding template template-parameter. Adjust
7125 PARGS as appropriate for application to ARG's template, and if ARG is a
7126 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7127 arguments to the template template parameter. */
7129 static tree
7131 {
7135 {
7136 /* When comparing two template template-parameters in partial ordering,
7137 rewrite the one currently being used as an argument to have default
7138 arguments for all parameters. */
7144 }
7145 else
7146 {
7147 tree aparms
7152 }
7155 }
7157 /* Subroutine of unify for the case when PARM is a
7158 BOUND_TEMPLATE_TEMPLATE_PARM. */
7160 static int
7163 {
7167 /* The template template parm might be variadic and the argument
7168 not, so flatten both argument lists. */
7173 {
7174 /* In keeping with P0522R0, adjust P's template arguments
7175 to apply to A's template; then flatten it again. */
7184 /* If the P0522 adjustment eliminated a pack expansion, deduce
7185 empty packs. */
7191 }
7192 else
7193 {
7194 /* Deduce arguments T, i from TT<T> or TT<i>.
7195 We check each element of PARMVEC and ARGVEC individually
7196 rather than the whole TREE_VEC since they can have
7197 different number of elements, which is allowed under N2555. */
7201 /* Check if the parameters end in a pack, making them
7202 variadic. */
7209 /* If the template argument list of P contains a pack
7210 expansion that is not the last template argument, the
7211 entire template argument list is a non-deduced
7212 context. */
7230 DEDUCE_EXACT,
7233 }
7236 }
7238 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7239 template template parameters. Both PARM_PARMS and ARG_PARMS are
7240 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7241 or PARM_DECL.
7243 Consider the example:
7244 template <class T> class A;
7245 template<template <class U> class TT> class B;
7247 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7248 the parameters to A, and OUTER_ARGS contains A. */
7250 static int
7252 tree arg_parms,
7253 tsubst_flags_t complain,
7254 tree in_decl,
7255 tree outer_args)
7256 {
7268 {
7269 /* P0522R0: A template template-parameter P is at least as specialized as
7270 a template template-argument A if, given the following rewrite to two
7271 function templates, the function template corresponding to P is at
7272 least as specialized as the function template corresponding to A
7273 according to the partial ordering rules for function templates
7274 ([temp.func.order]). Given an invented class template X with the
7275 template parameter list of A (including default arguments):
7277 * Each of the two function templates has the same template parameters,
7278 respectively, as P or A.
7280 * Each function template has a single function parameter whose type is
7281 a specialization of X with template arguments corresponding to the
7282 template parameters from the respective function template where, for
7283 each template parameter PP in the template parameter list of the
7284 function template, a corresponding template argument AA is formed. If
7285 PP declares a parameter pack, then AA is the pack expansion
7286 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7288 If the rewrite produces an invalid type, then P is not at least as
7289 specialized as A. */
7291 /* So coerce P's args to apply to A's parms, and then deduce between A's
7292 args and the converted args. If that succeeds, A is at least as
7293 specialized as P, so they match.*/
7300 {
7306 }
7307 }
7309 /* Determine whether we have a parameter pack at the end of the
7310 template template parameter's template parameter list. */
7312 {
7319 {
7333 }
7334 }
7340 /* Check all of the template parameters except the parameter pack at
7341 the end (if any). */
7343 {
7352 outer_args))
7355 }
7358 {
7359 /* Check each of the template parameters in the template
7360 argument against the template parameter pack at the end of
7361 the template template parameter. */
7368 {
7375 outer_args))
7377 }
7378 }
7381 }
7383 /* Verifies that the deduced template arguments (in TARGS) for the
7384 template template parameters (in TPARMS) represent valid bindings,
7385 by comparing the template parameter list of each template argument
7386 to the template parameter list of its corresponding template
7387 template parameter, in accordance with DR150. This
7388 routine can only be called after all template arguments have been
7389 deduced. It will return TRUE if all of the template template
7390 parameter bindings are okay, FALSE otherwise. */
7391 bool
7393 {
7397 /* We're dealing with template parms in this process. */
7403 {
7408 {
7413 {
7414 /* Look inside the argument pack. */
7417 }
7420 {
7424 /* Extract the next argument from the argument
7425 pack. */
7429 /* Look at the pattern of the pack expansion. */
7432 /* Extract the template parameters from the template
7433 argument. */
7439 /* Verify that we can coerce the template template
7440 parameters from the template argument to the template
7441 parameter. This requires an exact match. */
7443 && !coerce_template_template_parms
7445 targ_parms,
7446 tf_none,
7447 tparm,
7448 targs))
7449 {
7452 }
7453 }
7454 }
7455 }
7457 out:
7461 }
7463 /* Since type attributes aren't mangled, we need to strip them from
7464 template type arguments. */
7466 static tree
7468 {
7478 }
7480 /* And from inside dependent non-type arguments like sizeof(Type). */
7482 static tree
7484 {
7494 }
7496 // A template declaration can be substituted for a constrained
7497 // template template parameter only when the argument is more
7498 // constrained than the parameter.
7499 static bool
7501 {
7504 /* For now, allow constrained template template arguments
7505 and unconstrained template template parameters. */
7511 // If the template parameter is constrained, we need to rewrite its
7512 // constraints in terms of the ARG's template parameters. This ensures
7513 // that all of the template parameter types will have the same depth.
7514 //
7515 // Note that this is only valid when coerce_template_template_parm is
7516 // true for the innermost template parameters of PARM and ARG. In other
7517 // words, because coercion is successful, this conversion will be valid.
7519 {
7526 }
7529 }
7531 // Convert a placeholder argument into a binding to the original
7532 // parameter. The original parameter is saved as the TREE_TYPE of
7533 // ARG.
7536 {
7539 }
7541 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
7542 because one of them is dependent. But we need to represent the
7543 conversion for the benefit of cp_tree_equal. */
7545 static tree
7547 {
7548 /* Auto parms get no conversion. */
7551 /* We don't need or want to add this conversion now if we're going to use the
7552 argument for deduction. */
7564 }
7566 /* Convert the indicated template ARG as necessary to match the
7567 indicated template PARM. Returns the converted ARG, or
7568 error_mark_node if the conversion was unsuccessful. Error and
7569 warning messages are issued under control of COMPLAIN. This
7570 conversion is for the Ith parameter in the parameter list. ARGS is
7571 the full set of template arguments deduced so far. */
7573 static tree
7575 tree arg,
7576 tree args,
7577 tsubst_flags_t complain,
7579 tree in_decl)
7580 {
7581 tree orig_arg;
7582 tree val;
7588 /* Trivially convert placeholders. */
7597 {
7598 /* The template argument was the name of some
7599 member function. That's usually
7600 invalid, but static members are OK. In any
7601 case, grab the underlying fields/functions
7602 and issue an error later if required. */
7605 }
7613 /* When determining whether an argument pack expansion is a template,
7614 look at the pattern. */
7618 /* Deal with an injected-class-name used as a template template arg. */
7620 {
7623 {
7633 }
7634 }
7636 is_tmpl_type =
7652 {
7654 {
7658 }
7661 "to refer to a type member of a template parameter, "
7666 typename_type,
7667 complain);
7670 }
7672 {
7674 {
7676 {
7688 else
7691 }
7692 }
7694 }
7696 {
7698 {
7705 else
7708 }
7710 }
7713 /* We already did the appropriate conversion when packing args. */
7716 {
7718 {
7720 /* The number of argument required is not known yet.
7721 Just accept it for now. */
7723 else
7724 {
7726 tree argparm;
7728 /* Strip alias templates that are equivalent to another
7729 template. */
7735 args))
7736 {
7739 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7740 TEMPLATE_DECL. */
7742 {
7747 }
7748 }
7749 else
7750 {
7752 {
7759 }
7762 }
7764 // Check that the constraints are compatible before allowing the
7765 // substitution.
7768 {
7770 {
7776 }
7778 }
7779 }
7780 }
7781 else
7783 /* We only form one instance of each template specialization.
7784 Therefore, if we use a non-canonical variant (i.e., a
7785 typedef), any future messages referring to the type will use
7786 the typedef, which is confusing if those future uses do not
7787 themselves also use the typedef. */
7790 }
7791 else
7792 {
7796 {
7800 }
7801 else
7809 /* We used to call digest_init here. However, digest_init
7810 will report errors, which we don't want when complain
7811 is zero. More importantly, digest_init will try too
7812 hard to convert things: for example, `0' should not be
7813 converted to pointer type at this point according to
7814 the standard. Accepting this is not merely an
7815 extension, since deciding whether or not these
7816 conversions can occur is part of determining which
7817 function template to call, or whether a given explicit
7818 argument specification is valid. */
7820 else
7821 {
7824 }
7834 {
7835 /* Reject template arguments that are references to built-in
7836 functions with no library fallbacks. */
7845 }
7848 {
7849 /* Strip typedefs from the SCOPE_REF. */
7852 complain);
7855 }
7856 }
7859 }
7861 /* Coerces the remaining template arguments in INNER_ARGS (from
7862 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
7863 Returns the coerced argument pack. PARM_IDX is the position of this
7864 parameter in the template parameter list. ARGS is the original
7865 template argument list. */
7866 static tree
7869 tree args,
7870 tree inner_args,
7872 tree new_args,
7874 tree in_decl,
7875 tsubst_flags_t complain)
7876 {
7879 tree packed_args;
7880 tree argument_pack;
7887 {
7888 /* When the template parameter is a non-type template parameter pack
7889 or template template parameter pack whose type or template
7890 parameters use parameter packs, we know exactly how many arguments
7891 we are looking for. Build a vector of the instantiated decls for
7892 these template parameters in PACKED_PARMS. */
7893 /* We can't use make_pack_expansion here because it would interpret a
7894 _DECL as a use rather than a declaration. */
7908 /* If we're doing a partial instantiation of a member template,
7909 verify that all of the types used for the non-type
7910 template parameter pack are, in fact, valid for non-type
7911 template parameters. */
7914 {
7917 {
7921 }
7922 /* We don't know how many args we have yet, just
7923 use the unconverted ones for now. */
7925 }
7928 }
7929 /* Check if we have a placeholder pack, which indicates we're
7930 in the context of a introduction list. In that case we want
7931 to match this pack to the single placeholder. */
7935 {
7938 }
7939 else
7942 /* Convert the remaining arguments, which will be a part of the
7943 parameter pack "parm". */
7946 {
7952 {
7953 /* Once we've packed as many args as we have types, stop. */
7957 /* We don't know how many args we have yet, just
7958 use the unconverted ones for now. */
7960 else
7962 }
7965 {
7968 }
7969 else
7972 in_decl);
7976 }
7980 {
7985 }
7990 else
7991 {
7994 }
8001 }
8003 /* Returns the number of pack expansions in the template argument vector
8004 ARGS. */
8006 static int
8008 {
8013 {
8017 }
8019 }
8021 /* Convert all template arguments to their appropriate types, and
8022 return a vector containing the innermost resulting template
8023 arguments. If any error occurs, return error_mark_node. Error and
8024 warning messages are issued under control of COMPLAIN.
8026 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8027 for arguments not specified in ARGS. Otherwise, if
8028 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
8029 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
8030 USE_DEFAULT_ARGS is false, then all arguments must be specified in
8031 ARGS. */
8033 static tree
8035 tree args,
8036 tree in_decl,
8037 tsubst_flags_t complain,
8040 {
8042 tree orig_inner_args;
8043 tree inner_args;
8044 tree new_args;
8045 tree new_inner_args;
8049 /* When used as a boolean value, indicates whether this is a
8050 variadic template parameter list. Since it's an int, we can also
8051 subtract it from nparms to get the number of non-variadic
8052 parameters. */
8057 /* Likewise for parameters with default arguments. */
8065 /* Determine if there are any parameter packs or default arguments. */
8067 {
8075 }
8078 /* If there are no parameters that follow a parameter pack, we need to
8079 expand any argument packs so that we can deduce a parameter pack from
8080 some non-packed args followed by an argument pack, as in variadic85.C.
8081 If there are such parameters, we need to leave argument packs intact
8082 so the arguments are assigned properly. This can happen when dealing
8083 with a nested class inside a partial specialization of a class
8084 template, as in variadic92.C, or when deducing a template parameter pack
8085 from a sub-declarator, as in variadic114.C. */
8089 /* Count any pack expansion args. */
8095 && require_all_args
8096 && !variadic_args_p
8097 && (!use_default_args
8100 {
8102 {
8104 {
8108 }
8109 else
8116 }
8119 }
8120 /* We can't pass a pack expansion to a non-pack parameter of an alias
8121 template (DR 1430). */
8125 && variadic_args_p
8127 {
8129 {
8131 {
8137 {
8140 "pack expansion argument for non-pack parameter "
8142 else
8144 "pack expansion argument for non-pack parameter "
8148 }
8149 }
8151 found:;
8152 }
8154 }
8156 /* We need to evaluate the template arguments, even though this
8157 template-id may be nested within a "sizeof". */
8166 {
8167 tree arg;
8168 tree parm;
8170 /* Get the Ith template parameter. */
8174 {
8177 }
8179 /* Calculate the next argument. */
8182 else
8187 {
8188 /* Some arguments will be placed in the
8189 template parameter pack PARM. */
8196 {
8197 /* We don't know how many args we have yet, just use the
8198 unconverted (and still packed) ones for now. */
8202 }
8206 /* Store this argument. */
8208 {
8209 lost++;
8210 /* We are done with all of the arguments. */
8212 }
8213 else
8214 {
8217 }
8220 }
8222 {
8224 {
8225 /* "If every valid specialization of a variadic template
8226 requires an empty template parameter pack, the template is
8227 ill-formed, no diagnostic required." So check that the
8228 pattern works with this parameter. */
8233 in_decl);
8235 {
8240 }
8242 /* Recover from missing typename. */
8246 /* We don't know how many args we have yet, just
8247 use the unconverted ones for now. */
8251 }
8252 }
8254 {
8255 /* There must be a default arg in this case. */
8258 /* The position of the first default template argument,
8259 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8260 Record that. */
8264 }
8265 else
8269 {
8272 }
8274 /* This only occurs if there was an error in the template
8275 parameter list itself (which we would already have
8276 reported) that we are trying to recover from, e.g., a class
8277 template with a parameter list such as
8278 template<typename..., typename>. */
8280 else
8286 lost++;
8288 }
8293 {
8295 {
8300 }
8302 }
8312 }
8314 /* Convert all template arguments to their appropriate types, and
8315 return a vector containing the innermost resulting template
8316 arguments. If any error occurs, return error_mark_node. Error and
8317 warning messages are not issued.
8319 Note that no function argument deduction is performed, and default
8320 arguments are used to fill in unspecified arguments. */
8321 tree
8323 {
8325 }
8327 /* Convert all template arguments to their appropriate type, and
8328 instantiate default arguments as needed. This returns a vector
8329 containing the innermost resulting template arguments, or
8330 error_mark_node if unsuccessful. */
8331 tree
8333 tsubst_flags_t complain)
8334 {
8336 }
8338 /* Like coerce_template_parms. If PARMS represents all template
8339 parameters levels, this function returns a vector of vectors
8340 representing all the resulting argument levels. Note that in this
8341 case, only the innermost arguments are coerced because the
8342 outermost ones are supposed to have been coerced already.
8344 Otherwise, if PARMS represents only (the innermost) vector of
8345 parameters, this function returns a vector containing just the
8346 innermost resulting arguments. */
8348 static tree
8350 tree args,
8351 tree in_decl,
8352 tsubst_flags_t complain,
8355 {
8358 tree coerced_args;
8361 {
8363 tree level;
8369 {
8370 tree l;
8374 require_all_args,
8375 use_default_args);
8376 else
8383 }
8384 }
8385 else
8388 require_all_args,
8389 use_default_args);
8391 }
8393 /* Returns 1 if template args OT and NT are equivalent. */
8395 int
8397 {
8406 /* For member templates */
8415 {
8432 }
8436 {
8439 /* Don't treat an alias template specialization with dependent
8440 arguments as equivalent to its underlying type when used as a
8441 template argument; we need them to be distinct so that we
8442 substitute into the specialization arguments at instantiation
8443 time. And aliases can't be equivalent without being ==, so
8444 we don't need to look any deeper.
8446 During partial ordering, however, we need to treat them normally so
8447 that we can order uses of the same alias with different
8448 cv-qualification (79960). */
8452 else
8454 }
8457 else
8458 {
8459 /* Try to treat a template non-type argument that has been converted
8460 to the parameter type as equivalent to one that hasn't yet. */
8473 }
8474 }
8476 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8477 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8478 NEWARG_PTR with the offending arguments if they are non-NULL. */
8480 int
8484 {
8497 {
8502 {
8508 }
8509 }
8511 }
8515 {
8517 }
8519 static void
8521 {
8531 /* We are called both from instantiate_decl, where we've already had a
8532 tinst_level pushed, and instantiate_template, where we haven't.
8533 Compensate. */
8544 else
8553 }
8556 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
8557 ARGLIST. Valid choices for FNS are given in the cp-tree.def
8558 documentation for TEMPLATE_ID_EXPR. */
8560 tree
8562 {
8563 tree type;
8571 {
8574 }
8577 {
8579 unknown_type_node,
8581 arglist);
8583 }
8590 }
8592 /* Within the scope of a template class S<T>, the name S gets bound
8593 (in build_self_reference) to a TYPE_DECL for the class, not a
8594 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
8595 or one of its enclosing classes, and that type is a template,
8596 return the associated TEMPLATE_DECL. Otherwise, the original
8597 DECL is returned.
8599 Also handle the case when DECL is a TREE_LIST of ambiguous
8600 injected-class-names from different bases. */
8602 tree
8604 {
8608 /* DR 176: A lookup that finds an injected-class-name (10.2
8609 [class.member.lookup]) can result in an ambiguity in certain cases
8610 (for example, if it is found in more than one base class). If all of
8611 the injected-class-names that are found refer to specializations of
8612 the same class template, and if the name is followed by a
8613 template-argument-list, the reference refers to the class template
8614 itself and not a specialization thereof, and is not ambiguous. */
8616 {
8619 {
8625 }
8628 else
8630 }
8636 }
8638 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
8639 parameters, find the desired type.
8641 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
8643 IN_DECL, if non-NULL, is the template declaration we are trying to
8644 instantiate.
8646 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
8647 the class we are looking up.
8649 Issue error and warning messages under control of COMPLAIN.
8651 If the template class is really a local class in a template
8652 function, then the FUNCTION_CONTEXT is the function in which it is
8653 being instantiated.
8655 ??? Note that this function is currently called *twice* for each
8656 template-id: the first time from the parser, while creating the
8657 incomplete type (finish_template_type), and the second type during the
8658 real instantiation (instantiate_template_class). This is surely something
8659 that we want to avoid. It also causes some problems with argument
8660 coercion (see convert_nontype_argument for more information on this). */
8662 static tree
8665 {
8667 tree t;
8670 spec_entry elt;
8671 hashval_t hash;
8674 {
8678 else
8679 {
8686 }
8689 }
8691 {
8694 /* If we are declaring a constructor, say A<T>::A<T>, we will get
8695 an implicit typename for the second A. Deal with it. */
8700 {
8703 }
8704 }
8707 {
8710 }
8712 {
8716 }
8718 {
8721 }
8723 /* Issue an error message if we didn't find a template. */
8725 {
8729 }
8732 /* Make sure it's a user visible template, if it was named by
8733 the user. */
8736 {
8738 {
8742 }
8744 }
8748 /* An alias that just changes the name of a template is equivalent to the
8749 other template, so if any of the arguments are pack expansions, strip
8750 the alias to avoid problems with a pack expansion passed to a non-pack
8751 alias template parameter (DR 1430). */
8756 {
8757 tree parm;
8766 }
8767 else
8768 {
8770 tree gen_tmpl;
8771 tree type_decl;
8779 /* An error occurred while building the template TEMPL, and a
8780 diagnostic has most certainly been emitted for that
8781 already. Let's propagate that error. */
8790 {
8791 /* We've been given an incomplete set of template arguments.
8792 For example, given:
8794 template <class T> struct S1 {
8795 template <class U> struct S2 {};
8796 template <class U> struct S2<U*> {};
8797 };
8799 we will be called with an ARGLIST of `U*', but the
8800 TEMPLATE will be `template <class T> template
8801 <class U> struct S1<T>::S2'. We must fill in the missing
8802 arguments. */
8806 }
8808 /* Now we should have enough arguments. */
8811 /* From here on, we're only interested in the most general
8812 template. */
8814 /* Calculate the BOUND_ARGS. These will be the args that are
8815 actually tsubst'd into the definition to create the
8816 instantiation. */
8818 complain,
8823 /* We were unable to bind the arguments. */
8826 /* In the scope of a template class, explicit references to the
8827 template class refer to the type of the template, not any
8828 instantiation of it. For example, in:
8830 template <class T> class C { void f(C<T>); }
8832 the `C<T>' is just the same as `C'. Outside of the
8833 class, however, such a reference is an instantiation. */
8837 {
8842 }
8844 /* If we already have this specialization, return it. */
8854 /* If the the template's constraints are not satisfied,
8855 then we cannot form a valid type.
8857 Note that the check is deferred until after the hash
8858 lookup. This prevents redundant checks on previously
8859 instantiated specializations. */
8861 {
8863 {
8866 }
8868 }
8872 /* If the deduced arguments are invalid, then the binding
8873 failed. */
8877 complain))
8884 {
8889 }
8899 /* Create the type. */
8901 {
8902 /* The user referred to a specialization of an alias
8903 template represented by GEN_TMPL.
8905 [temp.alias]/2 says:
8907 When a template-id refers to the specialization of an
8908 alias template, it is equivalent to the associated
8909 type obtained by substitution of its
8910 template-arguments for the template-parameters in the
8911 type-id of the alias template. */
8914 /* Note that the call above (by indirectly calling
8915 register_specialization in tsubst_decl) registers the
8916 TYPE_DECL representing the specialization of the alias
8917 template. So next time someone substitutes ARGLIST for
8918 the template parms into the alias template (GEN_TMPL),
8919 she'll get that TYPE_DECL back. */
8923 }
8925 {
8927 {
8938 }
8939 else
8940 {
8941 /* We don't want to call start_enum for this type, since
8942 the values for the enumeration constants may involve
8943 template parameters. And, no one should be interested
8944 in the enumeration constants for such a type. */
8947 }
8951 }
8953 {
8959 /* A local class. Make sure the decl gets registered properly. */
8964 /* This instantiation is another name for the primary
8965 template type. Set the TYPE_CANONICAL field
8966 appropriately. */
8969 /* Some of the template arguments require structural
8970 equality testing, so this template class requires
8971 structural equality testing. */
8973 }
8974 else
8977 /* If we called start_enum or pushtag above, this information
8978 will already be set up. */
8980 {
8987 }
8988 else
8992 {
8998 {
9001 }
9002 }
9006 {
9010 {
9011 tree attributes
9019 }
9020 }
9022 /* Let's consider the explicit specialization of a member
9023 of a class template specialization that is implicitly instantiated,
9024 e.g.:
9025 template<class T>
9026 struct S
9027 {
9028 template<class U> struct M {}; //#0
9029 };
9031 template<>
9032 template<>
9033 struct S<int>::M<char> //#1
9034 {
9035 int i;
9036 };
9037 [temp.expl.spec]/4 says this is valid.
9039 In this case, when we write:
9040 S<int>::M<char> m;
9042 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
9043 the one of #0.
9045 When we encounter #1, we want to store the partial instantiation
9046 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
9048 For all cases other than this "explicit specialization of member of a
9049 class template", we just want to store the most general template into
9050 the CLASSTYPE_TI_TEMPLATE of M.
9052 This case of "explicit specialization of member of a class template"
9053 only happens when:
9054 1/ the enclosing class is an instantiation of, and therefore not
9055 the same as, the context of the most general template, and
9056 2/ we aren't looking at the partial instantiation itself, i.e.
9057 the innermost arguments are not the same as the innermost parms of
9058 the most general template.
9060 So it's only when 1/ and 2/ happens that we want to use the partial
9061 instantiation of the member template in lieu of its most general
9062 template. */
9066 /* the enclosing class must be an instantiation... */
9069 {
9073 tree partial_inst_args =
9080 use_partial_inst_tmpl =
9081 /*...and we must not be looking at the partial instantiation
9082 itself. */
9084 partial_inst_args);
9085 }
9088 /* This case is easy; there are no member templates involved. */
9090 else
9091 {
9092 /* This is a full instantiation of a member template. Find
9093 the partial instantiation of which this is an instance. */
9095 /* Temporarily reduce by one the number of levels in the ARGLIST
9096 so as to avoid comparing the last set of arguments. */
9100 /* FOUND is either a proper class type, or an alias
9101 template specialization. In the later case, it's a
9102 TYPE_DECL, resulting from the substituting of arguments
9103 for parameters in the TYPE_DECL of the alias template
9104 done earlier. So be careful while getting the template
9105 of FOUND. */
9107 ? found
9111 }
9113 // Build template info for the new specialization.
9122 /* Note this use of the partial instantiation so we can check it
9123 later in maybe_process_partial_specialization. */
9130 /* Now that the type has been registered on the instantiations
9131 list, we set up the enumerators. Because the enumeration
9132 constants may involve the enumeration type itself, we make
9133 sure to register the type first, and then create the
9134 constants. That way, doing tsubst_expr for the enumeration
9135 constants won't result in recursive calls here; we'll find
9136 the instantiation and exit above. */
9140 /* If the type makes use of template parameters, the
9141 code that generates debugging information will crash. */
9144 /* Possibly limit visibility based on template args. */
9151 }
9152 }
9154 /* Wrapper for lookup_template_class_1. */
9156 tree
9159 {
9160 tree ret;
9166 }
9168 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
9170 tree
9172 {
9173 /* The type of the expression is NULL_TREE since the template-id could refer
9174 to an explicit or partial specialization. */
9177 /* Except that concepts are always bool. */
9180 }
9182 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9184 tree
9186 {
9190 /* We never want to return a VAR_DECL for a variable concept, since they
9191 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
9206 {
9208 {
9211 }
9213 }
9215 /* If a template-id refers to a specialization of a variable
9216 concept, then the expression is true if and only if the
9217 concept's constraints are satisfied by the given template
9218 arguments.
9220 NOTE: This is an extension of Concepts Lite TS that
9221 allows constraints to be used in expressions. */
9223 {
9226 }
9229 }
9231 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
9232 TARGS template args, and instantiate it if it's not dependent. */
9234 tree
9236 tsubst_flags_t complain)
9237 {
9240 {
9243 }
9246 }
9248 \f
9249 struct pair_fn_data
9250 {
9251 tree_fn_t fn;
9252 tree_fn_t any_fn;
9254 /* True when we should also visit template parameters that occur in
9255 non-deduced contexts. */
9258 };
9260 /* Called from for_each_template_parm via walk_tree. */
9262 static tree
9264 {
9271 #define WALK_SUBTREE(NODE) \
9272 do \
9273 { \
9274 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
9275 pfd->include_nondeduced_p, \
9276 pfd->any_fn); \
9277 if (result) goto out; \
9278 } \
9279 while (0)
9289 {
9293 /* Fall through. */
9299 else
9309 /* Since we're not going to walk subtrees, we have to do this
9310 explicitly here. */
9312 /* Fall through. */
9315 /* Check the return type. */
9318 /* Check the parameter types. Since default arguments are not
9319 instantiated until they are needed, the TYPE_ARG_TYPES may
9320 contain expressions that involve template parameters. But,
9321 no-one should be looking at them yet. And, once they're
9322 instantiated, they don't contain template parameters, so
9323 there's no point in looking at them then, either. */
9324 {
9325 tree parm;
9330 /* Since we've already handled the TYPE_ARG_TYPES, we don't
9331 want walk_tree walking into them itself. */
9333 }
9336 {
9340 }
9357 /* Fall through. */
9369 /* Record template parameters such as `T' inside `TT<T>'. */
9371 /* Fall through. */
9383 /* A template template parameter is encountered. */
9387 /* Already substituted template template parameter */
9392 /* A template-id in a TYPENAME_TYPE might be a deduced context after
9393 partial instantiation. */
9405 /* If there's no type, then this thing must be some expression
9406 involving template parameters. */
9428 }
9430 #undef WALK_SUBTREE
9432 /* We didn't find any template parameters we liked. */
9433 out:
9435 }
9437 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9438 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9439 call FN with the parameter and the DATA.
9440 If FN returns nonzero, the iteration is terminated, and
9441 for_each_template_parm returns 1. Otherwise, the iteration
9442 continues. If FN never returns a nonzero value, the value
9443 returned by for_each_template_parm is 0. If FN is NULL, it is
9444 considered to be the function which always returns 1.
9446 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9447 parameters that occur in non-deduced contexts. When false, only
9448 visits those template parameters that can be deduced. */
9450 static tree
9454 tree_fn_t any_fn)
9455 {
9457 tree result;
9459 /* Set up. */
9465 /* Walk the tree. (Conceptually, we would like to walk without
9466 duplicates, but for_each_template_parm_r recursively calls
9467 for_each_template_parm, so we would need to reorganize a fair
9468 bit to use walk_tree_without_duplicates, so we keep our own
9469 visited list.) */
9472 else
9475 for_each_template_parm_r,
9479 /* Clean up. */
9481 {
9484 }
9487 }
9489 /* Returns true if T depends on any template parameter. */
9491 int
9493 {
9523 else
9524 {
9527 }
9532 }
9534 /* Returns true iff current_function_decl is an incompletely instantiated
9535 template. Useful instead of processing_template_decl because the latter
9536 is set to 0 during instantiate_non_dependent_expr. */
9538 bool
9540 {
9549 }
9551 /* Returns true if T depends on any template parameter with level LEVEL. */
9553 bool
9555 {
9558 }
9560 /* Returns true if the signature of DECL depends on any template parameter from
9561 its enclosing class. */
9563 bool
9565 {
9575 template_parm_outer_level,
9585 }
9587 /* Returns TRUE iff INST is an instantiation we don't need to do in an
9588 ill-formed translation unit, i.e. a variable or function that isn't
9589 usable in a constant expression. */
9593 {
9598 }
9600 /* Returns TRUE iff we should refuse to instantiate DECL because it's
9601 neglectable and instantiated from within an erroneous instantiation. */
9603 static bool
9605 {
9616 }
9624 /* We're starting to instantiate D; record the template instantiation context
9625 for diagnostics and to restore it later. */
9627 bool
9629 {
9631 }
9633 /* We're starting to instantiate D; record the template instantiation context
9634 at LOC for diagnostics and to restore it later. */
9636 bool
9638 {
9642 {
9643 /* Tell error.c not to try to instantiate any templates. */
9646 "template instantiation depth exceeds maximum of %d"
9648 max_tinst_depth);
9650 }
9652 /* If the current instantiation caused problems, don't let it instantiate
9653 anything else. Do allow deduction substitution and decls usable in
9654 constant expressions. */
9658 /* When not -quiet, dump template instantiations other than functions, since
9659 announce_function will take care of those. */
9678 }
9680 /* We're done instantiating this template; return to the instantiation
9681 context. */
9683 void
9685 {
9686 /* Restore the filename and line number stashed away when we started
9687 this instantiation. */
9691 }
9693 /* We're instantiating a deferred template; restore the template
9694 instantiation context in which the instantiation was requested, which
9695 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
9697 static tree
9699 {
9711 }
9713 /* Returns the TINST_LEVEL which gives the original instantiation
9714 context. */
9718 {
9724 }
9726 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
9727 vector of template arguments, as for tsubst.
9729 Returns an appropriate tsubst'd friend declaration. */
9731 static tree
9733 {
9734 tree new_friend;
9739 /* This was a friend declared with an explicit template
9740 argument list, e.g.:
9742 friend void f<>(T);
9744 to indicate that f was a template instantiation, not a new
9745 function declaration. Now, we have to figure out what
9746 instantiation of what template. */
9747 {
9749 tree new_args;
9750 tree tmpl;
9753 /* Friend functions are looked up in the containing namespace scope.
9754 We must enter that scope, to avoid finding member functions of the
9755 current class with same name. */
9770 tsk_none);
9772 }
9776 /* The NEW_FRIEND will look like an instantiation, to the
9777 compiler, but is not an instantiation from the point of view of
9778 the language. For example, we might have had:
9780 template <class T> struct S {
9781 template <class U> friend void f(T, U);
9782 };
9784 Then, in S<int>, template <class U> void f(int, U) is not an
9785 instantiation of anything. */
9791 {
9795 }
9797 /* The mangled name for the NEW_FRIEND is incorrect. The function
9798 is not a template instantiation and should not be mangled like
9799 one. Therefore, we forget the mangling here; we'll recompute it
9800 later if we need it. */
9802 {
9805 }
9808 {
9809 tree old_decl;
9810 tree new_friend_template_info;
9811 tree new_friend_result_template_info;
9812 tree ns;
9815 /* We must save some information from NEW_FRIEND before calling
9816 duplicate decls since that function will free NEW_FRIEND if
9817 possible. */
9819 new_friend_is_defn =
9824 {
9825 /* This declaration is a `primary' template. */
9828 new_friend_result_template_info
9830 }
9831 else
9834 /* Inside pushdecl_namespace_level, we will push into the
9835 current namespace. However, the friend function should go
9836 into the namespace of the template. */
9846 {
9847 /* This new friend declaration matched an existing
9848 declaration. For example, given:
9850 template <class T> void f(T);
9851 template <class U> class C {
9852 template <class T> friend void f(T) {}
9853 };
9855 the friend declaration actually provides the definition
9856 of `f', once C has been instantiated for some type. So,
9857 old_decl will be the out-of-class template declaration,
9858 while new_friend is the in-class definition.
9860 But, if `f' was called before this point, the
9861 instantiation of `f' will have DECL_TI_ARGS corresponding
9862 to `T' but not to `U', references to which might appear
9863 in the definition of `f'. Previously, the most general
9864 template for an instantiation of `f' was the out-of-class
9865 version; now it is the in-class version. Therefore, we
9866 run through all specialization of `f', adding to their
9867 DECL_TI_ARGS appropriately. In particular, they need a
9868 new set of outer arguments, corresponding to the
9869 arguments for this class instantiation.
9871 The same situation can arise with something like this:
9873 friend void f(int);
9874 template <class T> class C {
9875 friend void f(T) {}
9876 };
9878 when `C<int>' is instantiated. Now, `f(int)' is defined
9879 in the class. */
9882 /* On the other hand, if the in-class declaration does
9883 *not* provide a definition, then we don't want to alter
9884 existing definitions. We can just leave everything
9885 alone. */
9886 ;
9887 else
9888 {
9892 /* Overwrite whatever template info was there before, if
9893 any, with the new template information pertaining to
9894 the declaration. */
9898 {
9899 /* We should have called reregister_specialization in
9900 duplicate_decls. */
9905 /* Instantiate it if the global has already been used. */
9909 }
9910 else
9911 {
9912 tree t;
9914 /* Indicate that the old function template is a partial
9915 instantiation. */
9923 /* Reassign any specializations already in the hash table
9924 to the new more general template, and add the
9925 additional template args. */
9929 {
9931 spec_entry elt;
9943 register_specialization
9946 }
9948 }
9949 }
9951 /* The information from NEW_FRIEND has been merged into OLD_DECL
9952 by duplicate_decls. */
9954 }
9955 }
9956 else
9957 {
9961 /* In the code
9962 template <class T> class C {
9963 template <class U> friend void C1<U>::f (); // case 1
9964 friend void C2<T>::f (); // case 2
9965 };
9966 we only need to make sure CONTEXT is a complete type for
9967 case 2. To distinguish between the two cases, we note that
9968 CONTEXT of case 1 remains dependent type after tsubst while
9969 this isn't true for case 2. */
9979 {
9981 /* do_friend adds the TEMPLATE_DECL for any member friend
9982 template even if it isn't a member template, i.e.
9983 template <class T> friend A<T>::f();
9984 Look through it in that case. */
9988 /* Check to see that the declaration is really present, and,
9989 possibly obtain an improved declaration. */
9994 }
9995 }
9998 }
10000 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
10001 template arguments, as for tsubst.
10003 Returns an appropriate tsubst'd friend type or error_mark_node on
10004 failure. */
10006 static tree
10008 {
10009 tree tmpl;
10012 {
10015 }
10020 else
10028 {
10029 /* The friend template has already been declared. Just
10030 check to see that the declarations match, and install any new
10031 default parameters. We must tsubst the default parameters,
10032 of course. We only need the innermost template parameters
10033 because that is all that redeclare_class_template will look
10034 at. */
10037 {
10045 }
10046 }
10047 else
10048 {
10049 /* The friend template has not already been declared. In this
10050 case, the instantiation of the template class will cause the
10051 injection of this template into the namespace scope. */
10055 {
10056 /* The new TMPL is not an instantiation of anything, so we
10057 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
10058 for the new type because that is supposed to be the
10059 corresponding template decl, i.e., TMPL. */
10066 /* It is hidden. */
10071 /* Inject this template into the enclosing namspace scope. */
10073 }
10074 }
10078 else
10082 }
10084 /* Returns zero if TYPE cannot be completed later due to circularity.
10085 Otherwise returns one. */
10087 static int
10089 {
10099 else
10101 }
10106 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
10107 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
10109 static tree
10112 {
10121 {
10128 clauses
10132 else
10134 }
10135 /* If the first attribute argument is an identifier, don't
10136 pass it through tsubst. Attributes like mode, format,
10137 cleanup and several target specific attributes expect it
10138 unmodified. */
10140 {
10141 tree chain
10146 }
10148 {
10149 /* An attribute pack expansion. */
10158 {
10162 }
10164 }
10165 else
10172 }
10174 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
10175 unchanged or a new TREE_LIST chain. */
10177 static tree
10180 {
10185 {
10189 }
10193 {
10196 {
10199 {
10201 do
10206 }
10207 }
10209 }
10212 }
10214 /* Apply any attributes which had to be deferred until instantiation
10215 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
10216 ARGS, COMPLAIN, IN_DECL are as tsubst. */
10218 static void
10221 {
10223 tree t;
10230 {
10234 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
10235 to our attributes parameter. */
10237 }
10238 else
10239 {
10241 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
10242 lookup_template_class_1, and should be preserved. */
10246 }
10250 {
10254 }
10258 {
10263 {
10266 {
10270 do
10273 }
10274 else
10276 }
10279 }
10280 }
10282 /* Perform (or defer) access check for typedefs that were referenced
10283 from within the template TMPL code.
10284 This is a subroutine of instantiate_decl and instantiate_class_template.
10285 TMPL is the template to consider and TARGS is the list of arguments of
10286 that template. */
10288 static void
10290 {
10291 location_t saved_location;
10302 {
10314 /* Make access check error messages point to the location
10315 of the use of the typedef. */
10319 tf_warning_or_error);
10320 }
10322 }
10324 static tree
10326 {
10328 tree typedecl;
10329 tree pbinfo;
10330 tree base_list;
10332 tree fn_context;
10341 /* Figure out which template is being instantiated. */
10345 /* Determine what specialization of the original template to
10346 instantiate. */
10349 {
10352 }
10354 {
10355 /* This TYPE is actually an instantiation of a partial
10356 specialization. We replace the innermost set of ARGS with
10357 the arguments appropriate for substitution. For example,
10358 given:
10360 template <class T> struct S {};
10361 template <class T> struct S<T*> {};
10363 and supposing that we are instantiating S<int*>, ARGS will
10364 presently be {int*} -- but we need {int}. */
10367 }
10368 else
10369 {
10372 }
10374 /* If the template we're instantiating is incomplete, then clearly
10375 there's nothing we can do. */
10379 /* If we've recursively instantiated too many templates, stop. */
10383 /* Now we're really doing the instantiation. Mark the type as in
10384 the process of being defined. */
10387 /* We may be in the middle of deferred access check. Disable
10388 it now. */
10395 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10400 else
10401 {
10404 }
10405 /* Use #pragma pack from the template context. */
10411 /* Set the input location to the most specialized template definition.
10412 This is needed if tsubsting causes an error. */
10424 {
10427 /* Adjust visibility for template arguments. */
10429 }
10435 /* We should never instantiate a nested class before its enclosing
10436 class; we need to look up the nested class by name before we can
10437 instantiate it, and that lookup should instantiate the enclosing
10438 class. */
10444 {
10445 tree pbase_binfo;
10446 tree pushed_scope;
10449 /* We must enter the scope containing the type, as that is where
10450 the accessibility of types named in dependent bases are
10451 looked up from. */
10454 /* Substitute into each of the bases to determine the actual
10455 basetypes. */
10457 {
10458 tree base;
10464 {
10465 expanded_bases =
10472 }
10475 {
10477 /* Extract the already-expanded base class. */
10479 else
10480 /* Substitute to figure out the base class. */
10482 NULL_TREE);
10490 }
10491 }
10493 /* The list is now in reverse order; correct that. */
10498 }
10499 /* Now call xref_basetypes to set up all the base-class
10500 information. */
10508 /* Now that our base classes are set up, enter the scope of the
10509 class, so that name lookups into base classes, etc. will work
10510 correctly. This is precisely analogous to what we do in
10511 begin_class_definition when defining an ordinary non-template
10512 class, except we also need to push the enclosing classes. */
10515 /* Now members are processed in the order of declaration. */
10518 {
10522 {
10524 {
10525 /* Build new CLASSTYPE_NESTED_UTDS. */
10527 tree newtag;
10533 /* If the member is a class template, then -- even after
10534 substitution -- there may be dependent types in the
10535 template argument list for the class. We increment
10536 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
10537 that function will assume that no types are dependent
10538 when outside of a template. */
10548 {
10552 /* Unfortunately, lookup_template_class sets
10553 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
10554 instantiation (i.e., for the type of a member
10555 template class nested within a template class.)
10556 This behavior is required for
10557 maybe_process_partial_specialization to work
10558 correctly, but is not accurate in this case;
10559 the TAG is not an instantiation of anything.
10560 (The corresponding TEMPLATE_DECL is an
10561 instantiation, but the TYPE is not.) */
10564 /* Now, we call pushtag to put this NEWTAG into the scope of
10565 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
10566 pushtag calling push_template_decl. We don't have to do
10567 this for enums because it will already have been done in
10568 tsubst_enum. */
10572 }
10573 }
10575 {
10576 tree r;
10585 /* Instantiate members marked with attribute used. */
10591 }
10594 /* A closure type for a lambda in a default argument for a
10595 member template. Ignore it; it will be instantiated with
10597 else
10598 {
10599 /* Build new TYPE_FIELDS. */
10601 {
10602 tree condition;
10605 condition =
10615 }
10617 {
10618 tree r;
10622 /* The file and line for this declaration, to
10623 assist in error message reporting. Since we
10624 called push_tinst_level above, we don't need to
10625 restore these. */
10635 {
10636 /* A capture pack became multiple fields. */
10639 }
10642 {
10646 {
10647 /* In [temp.inst]:
10649 [t]he initialization (and any associated
10650 side-effects) of a static data member does
10651 not occur unless the static data member is
10652 itself used in a way that requires the
10653 definition of the static data member to
10654 exist.
10656 Therefore, we do not substitute into the
10657 initialized for the static data member here. */
10658 finish_static_data_member_decl
10664 /* Instantiate members marked with attribute used. */
10667 }
10669 {
10670 /* Determine whether R has a valid type and can be
10671 completed later. If R is invalid, then its type
10672 is replaced by error_mark_node. */
10678 {
10679 /* If R's type couldn't be completed and
10680 it isn't a flexible array member (whose
10681 type is incomplete by definition) give
10682 an error. */
10685 }
10686 }
10688 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10689 such a thing will already have been added to the field
10690 list by tsubst_enum in finish_member_declaration in the
10691 CLASSTYPE_NESTED_UTDS case above. */
10695 {
10698 }
10699 }
10700 }
10701 }
10702 }
10703 else
10704 {
10707 {
10708 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10714 {
10715 /* template <class T> friend class C; */
10718 }
10720 {
10721 /* template <class T> friend class C::D; */
10727 }
10730 {
10731 /* This could be either
10733 friend class T::C;
10735 when dependent_type_p is false or
10737 template <class U> friend class T::C;
10739 otherwise. */
10740 /* Bump processing_template_decl in case this is something like
10741 template <class T> friend struct A<T>::B. */
10748 }
10752 {
10753 /* friend class C;
10755 where C hasn't been declared yet. Let's lookup name
10756 from namespace scope directly, bypassing any name that
10757 come from dependent base class. */
10760 /* The call to xref_tag_from_type does injection for friend
10761 classes. */
10763 friend_type =
10767 }
10769 /* friend class C<T>; */
10772 /* Otherwise it's
10774 friend class C;
10776 where C is already declared or
10778 friend class C<int>;
10780 We don't have to do anything in these cases. */
10783 /* Trick make_friend_class into realizing that the friend
10784 we're adding is a template, not an ordinary class. It's
10785 important that we use make_friend_class since it will
10786 perform some error-checking and output cross-reference
10787 information. */
10795 }
10796 else
10797 {
10798 /* Build new DECL_FRIENDLIST. */
10799 tree r;
10801 /* The file and line for this declaration, to
10802 assist in error message reporting. Since we
10803 called push_tinst_level above, we don't need to
10804 restore these. */
10808 {
10811 }
10816 {
10819 }
10820 }
10821 }
10822 }
10825 {
10826 /* Restore these before substituting into the lambda capture
10827 initializers. */
10830 }
10833 {
10836 {
10842 {
10843 /* Set function_depth to avoid garbage collection. */
10847 }
10849 /* We need to instantiate the capture list from the template
10850 after we've instantiated the closure members, but before we
10851 consider adding the conversion op. Also keep any captures
10852 that may have been added during instantiation of the op(). */
10854 tree tmpl_cap
10863 }
10864 else
10866 }
10868 /* Set the file and line number information to whatever is given for
10869 the class itself. This puts error messages involving generated
10870 implicit functions at a predictable point, and the same point
10871 that would be used for non-template classes. */
10878 /* We don't instantiate default arguments for member functions. 14.7.1:
10880 The implicit instantiation of a class template specialization causes
10881 the implicit instantiation of the declarations, but not of the
10882 definitions or default arguments, of the class member functions,
10883 member classes, static data members and member templates.... */
10885 /* Some typedefs referenced from within the template code need to be access
10886 checked at template instantiation time, i.e now. These types were
10887 added to the template at parsing time. Let's get those and perform
10888 the access checks then. */
10898 /* The vtable for a template class can be emitted in any translation
10899 unit in which the class is instantiated. When there is no key
10900 method, however, finish_struct_1 will already have added TYPE to
10901 the keyed_classes. */
10906 }
10908 /* Wrapper for instantiate_class_template_1. */
10910 tree
10912 {
10913 tree ret;
10918 }
10920 static tree
10922 {
10923 tree r;
10929 else
10930 {
10937 }
10939 }
10941 /* Given a function parameter pack TMPL_PARM and some function parameters
10942 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
10943 and set *SPEC_P to point at the next point in the list. */
10945 tree
10947 {
10948 /* Collect all of the extra "packed" parameters into an
10949 argument pack. */
10950 tree parmvec;
10960 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
10966 /* Build the argument packs. */
10971 }
10973 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
10974 NONTYPE_ARGUMENT_PACK. */
10976 static tree
10978 {
10980 }
10982 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
10983 pack expansion with no extra args, 2 if it has extra args, or 0
10984 if it is not a pack expansion. */
10986 static int
10988 {
10994 /* A decl pack is itself an expansion. */
11001 }
11004 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
11006 static tree
11008 {
11015 }
11017 /* This is a subroutine of tsubst_pack_expansion.
11019 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
11020 mechanism to store the (non complete list of) arguments of the
11021 substitution and return a non substituted pack expansion, in order
11022 to wait for when we have enough arguments to really perform the
11023 substitution. */
11025 static bool
11029 {
11030 /* If one pack has an expansion and another pack has a normal
11031 argument or if one pack has an empty argument and an another
11032 one hasn't then tsubst_pack_expansion cannot perform the
11033 substitution and need to fall back on the
11034 PACK_EXPANSION_EXTRA mechanism. */
11042 {
11045 parm_pack;
11047 {
11052 /* We can't substitute a pack expansion with extra args into
11053 our pattern. */
11057 else
11059 }
11063 }
11065 }
11067 /* [temp.variadic]/6 says that:
11069 The instantiation of a pack expansion [...]
11070 produces a list E1,E2, ..., En, where N is the number of elements
11071 in the pack expansion parameters.
11073 This subroutine of tsubst_pack_expansion produces one of these Ei.
11075 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
11076 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
11077 PATTERN, and each TREE_VALUE is its corresponding argument pack.
11078 INDEX is the index 'i' of the element Ei to produce. ARGS,
11079 COMPLAIN, and IN_DECL are the same parameters as for the
11080 tsubst_pack_expansion function.
11082 The function returns the resulting Ei upon successful completion,
11083 or error_mark_node.
11085 Note that this function possibly modifies the ARGS parameter, so
11086 it's the responsibility of the caller to restore it. */
11088 static tree
11090 tree parm_packs,
11092 tree args /* This parm gets
11094 tsubst_flags_t complain,
11095 tree in_decl)
11096 {
11097 tree t;
11100 /* For each parameter pack, change the substitution of the parameter
11101 pack to the ith argument in its argument pack, then expand the
11102 pattern. */
11104 {
11109 ith_elem_is_expansion |=
11112 /* Select the Ith argument from the pack. */
11115 {
11117 {
11122 }
11123 else
11125 }
11126 else
11127 {
11132 {
11134 /* Update the corresponding argument. */
11136 }
11137 else
11138 /* Re-use the ARGUMENT_PACK_SELECT. */
11140 }
11142 }
11144 /* Substitute into the PATTERN with the (possibly altered)
11145 arguments. */
11147 /* Expanding a fixed parameter pack from
11148 coerce_template_parameter_pack. */
11153 {
11156 else
11159 }
11163 else
11166 /* If the Ith argument pack element is a pack expansion, then
11167 the Ith element resulting from the substituting is going to
11168 be a pack expansion as well. */
11173 }
11175 /* When the unexpanded parameter pack in a fold expression expands to an empty
11176 sequence, the value of the expression is as follows; the program is
11177 ill-formed if the operator is not listed in this table.
11179 && true
11180 || false
11181 , void() */
11183 tree
11185 {
11189 {
11198 }
11204 }
11206 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11207 form an expression that combines the two terms using the
11208 operator of T. */
11210 static tree
11212 {
11216 // Handle compound assignment operators.
11221 {
11231 complain);
11232 }
11233 }
11235 /* Substitute ARGS into the pack of a fold expression T. */
11239 {
11241 }
11243 /* Substitute ARGS into the pack of a fold expression T. */
11247 {
11249 }
11251 /* Expand a PACK of arguments into a grouped as left fold.
11252 Given a pack containing elements A0, A1, ..., An and an
11253 operator @, this builds the expression:
11255 ((A0 @ A1) @ A2) ... @ An
11257 Note that PACK must not be empty.
11259 The operator is defined by the original fold expression T. */
11261 static tree
11263 {
11266 {
11269 }
11271 }
11273 /* Substitute into a unary left fold expression. */
11275 static tree
11277 tree in_decl)
11278 {
11283 {
11287 }
11290 else
11292 }
11294 /* Substitute into a binary left fold expression.
11296 Do ths by building a single (non-empty) vector of argumnts and
11297 building the expression from those elements. */
11299 static tree
11301 tree in_decl)
11302 {
11311 {
11316 }
11324 }
11326 /* Expand a PACK of arguments into a grouped as right fold.
11327 Given a pack containing elementns A0, A1, ..., and an
11328 operator @, this builds the expression:
11330 A0@ ... (An-2 @ (An-1 @ An))
11332 Note that PACK must not be empty.
11334 The operator is defined by the original fold expression T. */
11336 tree
11338 {
11339 // Build the expression.
11343 {
11346 }
11348 }
11350 /* Substitute into a unary right fold expression. */
11352 static tree
11354 tree in_decl)
11355 {
11360 {
11364 }
11367 else
11369 }
11371 /* Substitute into a binary right fold expression.
11373 Do ths by building a single (non-empty) vector of arguments and
11374 building the expression from those elements. */
11376 static tree
11378 tree in_decl)
11379 {
11388 {
11393 }
11402 }
11405 /* Substitute ARGS into T, which is an pack expansion
11406 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
11407 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
11408 (if only a partial substitution could be performed) or
11409 ERROR_MARK_NODE if there was an error. */
11410 tree
11412 tree in_decl)
11413 {
11414 tree pattern;
11418 tree result;
11426 /* Add in any args remembered from an earlier partial instantiation. */
11431 /* Determine the argument packs that will instantiate the parameter
11432 packs used in the expansion expression. While we're at it,
11433 compute the number of arguments to be expanded and make sure it
11434 is consistent. */
11437 {
11444 {
11449 else
11452 }
11454 {
11455 /* ??? Support use in other patterns. */
11459 }
11461 {
11462 /* We know we have correct local_specializations if this
11463 expansion is at function scope, or if we're dealing with a
11464 local parameter in a requires expression; for the latter,
11465 tsubst_requires_expr set it up appropriately. */
11468 else
11469 /* We can't rely on local_specializations for a parameter
11470 name used later in a function declaration (such as in a
11471 late-specified return type). Even if it exists, it might
11472 have the wrong value for a recursive call. */
11476 {
11477 /* This parameter pack was used in an unevaluated context. Just
11478 make a dummy decl, since it's only used for its type. */
11481 /* Partial instantiation of the parm_pack, we can't build
11482 up an argument pack yet. */
11484 else
11486 }
11487 }
11490 else
11491 {
11497 }
11504 /* This can only happen if we forget to expand an argument
11505 pack somewhere else. Just return an error, silently. */
11506 {
11510 }
11513 {
11517 /* Don't bother trying to do a partial substitution with
11518 incomplete packs; we'll try again after deduction. */
11525 {
11530 pattern);
11531 else
11533 pattern);
11535 }
11537 /* Keep track of the parameter packs and their corresponding
11538 argument packs. */
11541 }
11542 else
11543 {
11544 /* We can't substitute for this parameter pack. We use a flag as
11545 well as the missing_level counter because function parameter
11546 packs don't have a level. */
11549 }
11550 }
11552 /* If the expansion is just T..., return the matching argument pack, unless
11553 we need to call convert_from_reference on all the elements. This is an
11554 important optimization; see c++/68422. */
11557 {
11559 /* Types need no adjustment, nor does sizeof..., and if we still have
11560 some pack expansion args we won't do anything yet. */
11565 /* Also optimize expression pack expansions if we can tell that the
11566 elements won't have reference type. */
11572 /* Otherwise use the normal path so we get convert_from_reference. */
11573 }
11575 /* We cannot expand this expansion expression, because we don't have
11576 all of the argument packs we need. */
11578 {
11579 /* We got some full packs, but we can't substitute them in until we
11580 have values for all the packs. So remember these until then. */
11585 }
11587 {
11588 /* There were no real arguments, we're just replacing a parameter
11589 pack with another version of itself. Substitute into the
11590 pattern and return a PACK_EXPANSION_*. The caller will need to
11591 deal with that. */
11595 else
11599 }
11604 {
11605 /* We're in a late-specified return type, so create our own local
11606 specializations map; the current map is either NULL or (in the
11607 case of recursive unification) might have bindings that we don't
11608 want to use or alter. */
11611 }
11613 /* For each argument in each argument pack, substitute into the
11614 pattern. */
11618 {
11620 i,
11622 in_decl);
11625 {
11628 }
11629 }
11631 /* Update ARGS to restore the substitution from parameter packs to
11632 their argument packs. */
11634 {
11640 else
11641 {
11649 /* Update the corresponding argument. */
11653 else
11655 }
11656 }
11659 {
11662 }
11664 /* If the dependent pack arguments were such that we end up with only a
11665 single pack expansion again, there's no need to keep it in a TREE_VEC. */
11671 }
11673 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
11674 TMPL. We do this using DECL_PARM_INDEX, which should work even with
11675 parameter packs; all parms generated from a function parameter pack will
11676 have the same DECL_PARM_INDEX. */
11678 tree
11680 {
11682 tree patparm;
11685 {
11691 }
11692 else
11693 {
11698 }
11701 }
11703 /* Make an argument pack out of the TREE_VEC VEC. */
11705 static tree
11707 {
11708 tree pack;
11712 else
11713 {
11716 }
11719 }
11721 /* Return an exact copy of template args T that can be modified
11722 independently. */
11724 static tree
11726 {
11734 {
11739 }
11745 }
11747 /* Substitute ARGS into the vector or list of template arguments T. */
11749 static tree
11751 {
11763 {
11765 tree new_arg;
11770 {
11771 /* Substitute into an expansion expression. */
11775 /* Add to the expanded length adjustment the number of
11776 expanded arguments. We subtract one from this
11777 measurement, because the argument pack expression
11778 itself is already counted as 1 in
11779 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
11780 the argument pack is empty. */
11782 }
11784 {
11785 /* Substitute into each of the arguments. */
11794 else
11799 }
11800 else
11809 }
11814 /* Make space for the expanded arguments coming from template
11815 argument packs. */
11817 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
11818 arguments for a member template.
11819 In that case each TREE_VEC in ORIG_T represents a level of template
11820 arguments, and ORIG_T won't carry any non defaulted argument count.
11821 It will rather be the nested TREE_VECs that will carry one.
11822 In other words, ORIG_T carries a non defaulted argument count only
11823 if it doesn't contain any nested TREE_VEC. */
11825 {
11829 }
11831 {
11835 {
11838 /* Now expand the template argument pack "in place". */
11841 }
11842 else
11843 {
11845 out++;
11846 }
11847 }
11850 }
11852 /* Substitute ARGS into one level PARMS of template parameters. */
11854 static tree
11856 {
11863 {
11871 }
11874 }
11876 /* Return the result of substituting ARGS into the template parameters
11877 given by PARMS. If there are m levels of ARGS and m + n levels of
11878 PARMS, then the result will contain n levels of PARMS. For
11879 example, if PARMS is `template <class T> template <class U>
11880 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
11881 result will be `template <int*, double, class V>'. */
11883 static tree
11885 {
11889 /* When substituting into a template, we must set
11890 PROCESSING_TEMPLATE_DECL as the template parameters may be
11891 dependent if they are based on one-another, and the dependency
11892 predicates are short-circuit outside of templates. */
11899 {
11906 }
11911 }
11913 /* Return the result of substituting ARGS into one template parameter
11914 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
11915 parameter and which TREE_PURPOSE is the default argument of the
11916 template parameter. */
11918 static tree
11920 {
11941 }
11943 /* Substitute the ARGS into the indicated aggregate (or enumeration)
11944 type T. If T is not an aggregate or enumeration type, it is
11945 handled as if by tsubst. IN_DECL is as for tsubst. If
11946 ENTERING_SCOPE is nonzero, T is the context for a template which
11947 we are presently tsubst'ing. Return the substituted value. */
11949 static tree
11951 tree args,
11952 tsubst_flags_t complain,
11953 tree in_decl,
11955 {
11960 {
11965 /* Fall through. */
11969 {
11970 tree argvec;
11971 tree context;
11972 tree r;
11976 /* In "sizeof(X<I>)" we need to evaluate "I". */
11982 /* First, determine the context for the type we are looking
11983 up. */
11986 {
11989 /* If context is a nested class inside a class template,
11990 it may still need to be instantiated (c++/33959). */
11992 }
11994 /* Then, figure out what arguments are appropriate for the
11995 type we are trying to find. For example, given:
11997 template <class T> struct S;
11998 template <class T, class U> void f(T, U) { S<U> su; }
12000 and supposing that we are instantiating f<int, double>,
12001 then our ARGS will be {int, double}, but, when looking up
12002 S we only want {double}. */
12007 else
12008 {
12012 }
12018 }
12019 else
12020 /* This is not a template type, so there's nothing to do. */
12025 }
12026 }
12030 /* Substitute into the default argument ARG (a default argument for
12031 FN), which has the indicated TYPE. */
12033 tree
12035 tsubst_flags_t complain)
12036 {
12041 /* This can happen in invalid code. */
12056 /* This default argument came from a template. Instantiate the
12057 default argument here, not in tsubst. In the case of
12058 something like:
12060 template <class T>
12061 struct S {
12062 static T t();
12063 void f(T = t());
12064 };
12066 we must be careful to do name lookup in the scope of S<T>,
12067 rather than in the current class. */
12069 /* The "this" pointer is not valid in a default argument. */
12071 {
12076 }
12081 /* The default argument expression may cause implicitly defined
12082 member functions to be synthesized, which will result in garbage
12083 collection. We must treat this situation as if we were within
12084 the body of function so as to avoid collecting live data on the
12085 stack. */
12095 /* Restore the "this" pointer. */
12097 {
12100 }
12107 /* Make sure the default argument is reasonable. */
12113 {
12117 }
12120 }
12122 /* Substitute into all the default arguments for FN. */
12124 static void
12126 {
12127 tree arg;
12128 tree tmpl_args;
12132 /* If this function is not yet instantiated, we certainly don't need
12133 its default arguments. */
12136 /* Don't do this again for clones. */
12142 arg;
12148 complain);
12149 }
12151 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
12153 static tree
12155 tree lambda_fntype)
12156 {
12161 /* Nobody should be tsubst'ing into non-template functions. */
12165 {
12166 /* If T is not dependent, just return it. */
12170 /* Calculate the most general template of which R is a
12171 specialization, and the complete set of arguments used to
12172 specialize R. */
12175 (DECL_TEMPLATE_RESULT
12181 /* Check to see if we already have this specialization. */
12183 {
12187 }
12189 /* We can see more levels of arguments than parameters if
12190 there was a specialization of a member template, like
12191 this:
12193 template <class T> struct S { template <class U> void f(); }
12194 template <> template <class U> void S<int>::f(U);
12196 Here, we'll be substituting into the specialization,
12197 because that's where we can find the code we actually
12198 want to generate, but we'll have enough arguments for
12199 the most general template.
12201 We also deal with the peculiar case:
12203 template <class T> struct S {
12204 template <class U> friend void f();
12205 };
12206 template <class U> void f() {}
12207 template S<int>;
12208 template void f<double>();
12210 Here, the ARGS for the instantiation of will be {int,
12211 double}. But, we only need as many ARGS as there are
12212 levels of template parameters in CODE_PATTERN. We are
12213 careful not to get fooled into reducing the ARGS in
12214 situations like:
12216 template <class T> struct S { template <class U> void f(U); }
12217 template <class T> template <> void S<T>::f(int) {}
12219 which we can spot because the pattern will be a
12220 specialization in this case. */
12227 }
12228 else
12229 {
12230 /* This special case arises when we have something like this:
12232 template <class T> struct S {
12233 friend void f<int>(int, double);
12234 };
12236 Here, the DECL_TI_TEMPLATE for the friend declaration
12237 will be an IDENTIFIER_NODE. We are being called from
12238 tsubst_friend_function, and we want only to create a
12239 new decl (R) with appropriate types so that we can call
12240 determine_specialization. */
12243 }
12260 /* If we hit excessive deduction depth, the type is bogus even if
12261 it isn't error_mark_node, so don't build a decl. */
12265 /* We do NOT check for matching decls pushed separately at this
12266 point, as they may not represent instantiations of this
12267 template, and in any case are considered separate under the
12268 discrete model. */
12272 /* Clear out the mangled name and RTL for the instantiation. */
12275 /* Leave DECL_INITIAL set on deleted instantiations. */
12280 /* OpenMP UDRs have the only argument a reference to the declared
12281 type. We want to diagnose if the declared type is a reference,
12282 which is invalid, but as references to references are usually
12283 quietly merged, diagnose it here. */
12285 {
12286 tree argtype
12291 "reference type %qT in "
12295 argtype);
12296 }
12299 /* Type-conversion operator. Reconstruct the name, in
12300 case it's the name of one of the template's parameters. */
12310 {
12314 }
12321 /* If this is an instantiation of a function with internal
12322 linkage, we already know what object file linkage will be
12323 assigned to the instantiation. */
12332 /* We'll re-clone as appropriate in instantiate_template. */
12335 /* If we aren't complaining now, return on error before we register
12336 the specialization so that we'll complain eventually. */
12342 /* When instantiating a constrained member, substitute
12343 into the constraints to create a new constraint. */
12346 {
12349 }
12351 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
12352 this in the special friend case mentioned above where
12353 GEN_TMPL is NULL. */
12355 {
12360 tree new_r
12363 /* We instantiated this while substituting into
12364 the type earlier (template/friend54.C). */
12367 /* We're not supposed to instantiate default arguments
12368 until they are called, for a template. But, for a
12369 declaration like:
12371 template <class T> void f ()
12372 { extern void g(int i = T()); }
12374 we should do the substitution when the template is
12375 instantiated. We handle the member function case in
12376 instantiate_class_template since the default arguments
12377 might refer to other members of the class. */
12382 }
12383 else
12386 /* Copy the list of befriending classes. */
12390 {
12394 }
12397 {
12401 /* If this is an instantiation of a member template, clone it.
12402 If it isn't, that'll be handled by
12403 clone_constructors_and_destructors. */
12406 }
12417 /* Possibly limit visibility based on template args. */
12420 {
12424 }
12433 }
12435 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
12437 static tree
12439 tree lambda_fntype)
12440 {
12441 /* We can get here when processing a member function template,
12442 member class template, or template template parameter. */
12445 tree spec;
12446 tree tmpl_args;
12447 tree full_args;
12448 tree r;
12452 {
12453 /* Template template parameter is treated here. */
12457 /* If we get a real template back, return it. This can happen in
12458 the context of most_specialized_partial_spec. */
12461 else
12462 /* The new TEMPLATE_DECL was built in
12463 reduce_template_parm_level. */
12466 }
12469 {
12470 /* We might already have an instance of this template.
12471 The ARGS are for the surrounding class type, so the
12472 full args contain the tsubst'd args for the context,
12473 plus the innermost args from the template decl. */
12477 /* Because this is a template, the arguments will still be
12478 dependent, even after substitution. If
12479 PROCESSING_TEMPLATE_DECL is not set, the dependency
12480 predicates will short-circuit. */
12488 /* If this is a default template template argument,
12489 tsubst might not have changed anything. */
12497 }
12499 /* Make a new template decl. It will be similar to the
12500 original, but will record the current template arguments.
12501 We also create a new function declaration, which is just
12502 like the old one, but points to this new template, rather
12503 than the old one. */
12508 // Build new template info linking to the original template decl.
12510 {
12513 }
12514 else
12517 /* The template parameters for this new template are all the
12518 template parameters for the old template, except the
12519 outermost level of parameters. */
12522 complain);
12526 {
12527 tree new_type;
12535 /* For a partial specialization, we need to keep pointing to
12536 the primary template. */
12542 }
12543 else
12544 {
12545 tree new_decl;
12549 else
12559 {
12562 }
12563 else
12564 {
12567 }
12568 }
12578 /* Record this non-type partial instantiation. */
12584 }
12586 /* True if FN is the op() for a lambda in an uninstantiated template. */
12588 bool
12590 {
12595 }
12597 /* True if FN is the op() for a lambda regenerated from a lambda in an
12598 uninstantiated template. */
12600 bool
12602 {
12605 }
12607 /* We're instantiating a variable from template function TCTX. Return the
12608 corresponding current enclosing scope. This gets complicated because lambda
12609 functions in templates are regenerated rather than instantiated, but generic
12610 lambda functions are subsequently instantiated. */
12612 static tree
12614 {
12622 {
12633 {
12637 }
12639 }
12641 }
12643 /* Substitute the ARGS into the T, which is a _DECL. Return the
12644 result of the substitution. Issue error and warning messages under
12645 control of COMPLAIN. */
12647 static tree
12649 {
12650 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
12651 location_t saved_loc;
12656 /* Set the filename and linenumber to improve error-reporting. */
12661 {
12671 {
12679 {
12680 /* If there is a local specialization that isn't a
12681 parameter pack, it means that we're doing a "simple"
12682 substitution from inside tsubst_pack_expansion. Just
12683 return the local specialization (which will be a single
12684 parm). */
12691 /* Expand the TYPE_PACK_EXPANSION that provides the types for
12692 the parameters in this function parameter pack. */
12696 {
12699 /* Zero-length parameter packs are boring. Just substitute
12700 into the chain. */
12704 }
12705 else
12706 {
12707 /* All we did was update the type. Make a note of that. */
12710 }
12711 }
12713 /* Loop through all of the parameters we'll build. When T is
12714 a function parameter pack, LEN is the number of expanded
12715 types in EXPANDED_TYPES; otherwise, LEN is 1. */
12718 {
12725 /* We're on the Ith parameter of the function parameter
12726 pack. */
12727 {
12728 /* Get the Ith type. */
12731 /* Rename the parameter to include the index. */
12734 }
12736 /* We're dealing with a normal parameter. */
12744 {
12747 else
12750 }
12760 /* Keep track of the first new parameter we
12761 generate. That's what will be returned to the
12762 caller. */
12766 /* Build a proper chain of parameters when substituting
12767 into a function parameter pack. */
12770 }
12772 /* If cp_unevaluated_operand is set, we're just looking for a
12773 single dummy parameter, so don't keep going. */
12778 /* FIRST_R contains the start of the chain we've built. */
12780 }
12784 {
12791 {
12792 /* This field is a lambda capture pack. Return a TREE_VEC of
12793 the expanded fields to instantiate_class_template_1 and
12794 store them in the specializations hash table as a
12795 NONTYPE_ARGUMENT_PACK so that tsubst_copy can find them. */
12799 {
12802 }
12803 else
12804 {
12805 /* All we did was update the type. Make a note of that. */
12808 }
12809 }
12812 {
12815 {
12819 }
12829 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
12830 number of bits. */
12836 {
12837 /* Set up DECL_TEMPLATE_INFO so that we can get at the
12838 NSDMI in perform_member_init. Still set DECL_INITIAL
12839 so that we know there is one. */
12844 }
12845 /* We don't have to set DECL_CONTEXT here; it is set by
12846 finish_member_declaration. */
12854 }
12857 {
12862 }
12863 }
12867 /* We reach here only for member using decls. We also need to check
12868 uses_template_parms because DECL_DEPENDENT_P is not set for a
12869 using-declaration that designates a member of the current
12870 instantiation (c++/53549). */
12873 {
12877 {
12882 {
12886 {
12889 }
12890 else
12891 {
12894 }
12896 }
12897 }
12898 else
12899 {
12905 else
12906 {
12909 }
12910 }
12911 }
12912 else
12913 {
12916 }
12921 {
12924 tree spec;
12926 tree ctx;
12935 {
12936 /* If this is the canonical decl, we don't have to
12937 mess with instantiations, and often we can't (for
12938 typename, template type parms and such). Note that
12939 TYPE_NAME is not correct for the above test if
12940 we've copied the type for a typedef. */
12946 }
12948 /* Check to see if we already have the specialization we
12949 need. */
12952 {
12953 /* T is a static data member or namespace-scope entity.
12954 We have to substitute into namespace-scope variables
12955 (not just variable templates) because of cases like:
12957 template <class T> void f() { extern T t; }
12959 where the entity referenced is not known until
12960 instantiation time. */
12964 {
12966 complain,
12968 /* If CTX is unchanged, then T is in fact the
12969 specialization we want. That situation occurs when
12970 referencing a static data member within in its own
12971 class. We can use pointer equality, rather than
12972 same_type_p, because DECL_CONTEXT is always
12973 canonical... */
12975 /* ... unless T is a member template; in which
12976 case our caller can be willing to create a
12977 specialization of that template represented
12978 by T. */
12982 }
12985 {
12990 argvec = (coerce_innermost_template_parms
12998 }
12999 }
13000 else
13001 {
13002 /* A local variable. */
13004 /* Subsequent calls to pushdecl will fill this in. */
13006 /* Unless this is a reference to a static variable from an
13007 enclosing function, in which case we need to fill it in now. */
13009 {
13013 }
13015 }
13016 /* If we already have the specialization we need, there is
13017 nothing more to do. */
13019 {
13022 }
13024 /* Create a new node for the specialization we need. */
13027 {
13030 else
13038 {
13039 /* Mask off any template args past the variable's context so we
13040 don't replace the auto with an unrelated argument. */
13044 /* This should never happen with the new lambda instantiation
13045 model, but keep the handling just in case. */
13048 }
13050 }
13052 {
13053 /* Even if the original location is out of scope, the
13054 newly substituted one is not. */
13061 {
13062 /* It may seem that this case cannot occur, since:
13064 typedef void f();
13065 void g() { f x; }
13067 declares a function, not a variable. However:
13069 typedef void f();
13070 template <typename T> void g() { T t; }
13071 template void g<f>();
13073 is an attempt to declare a variable with function
13074 type. */
13076 /* R is not yet sufficiently initialized, so we
13077 just use its name. */
13080 }
13082 /* Wait until cp_finish_decl to set this again, to handle
13083 circular dependency (template/instantiate6.C). */
13088 {
13093 {
13096 }
13098 }
13102 }
13108 /* Clear out the mangled name and RTL for the instantiation. */
13112 /* The initializer must not be expanded until it is required;
13113 see [temp.inst]. */
13117 {
13123 /* Possibly limit visibility based on template args. */
13126 {
13130 }
13132 }
13135 {
13136 /* A static data member declaration is always marked
13137 external when it is declared in-class, even if an
13138 initializer is present. We mimic the non-template
13139 processing here. */
13147 }
13148 else
13149 {
13154 }
13162 /* Preserve a typedef that names a type. */
13164 {
13168 /* An alias template specialization can be dependent
13169 even if its underlying type is not. */
13171 }
13174 }
13179 }
13180 #undef RETURN
13182 out:
13183 /* Restore the file and line information. */
13187 }
13189 /* Substitute into the ARG_TYPES of a function type.
13190 If END is a TREE_CHAIN, leave it and any following types
13191 un-substituted. */
13193 static tree
13195 tree args,
13196 tree end,
13197 tsubst_flags_t complain,
13198 tree in_decl)
13199 {
13200 tree remaining_arg_types;
13204 tree default_arg;
13215 {
13216 /* For a pack expansion, perform substitution on the
13217 entire expression. Later on, we'll handle the arguments
13218 one-by-one. */
13223 /* So that we'll spin through the parameters, one by one. */
13225 else
13226 {
13227 /* We only partially substituted into the parameter
13228 pack. Our type is TYPE_PACK_EXPANSION. */
13231 }
13232 }
13245 {
13247 {
13251 }
13253 }
13254 /* DR 657. */
13258 /* Do array-to-pointer, function-to-pointer conversion, and ignore
13259 top-level qualifiers as required. */
13262 /* We do not substitute into default arguments here. The standard
13263 mandates that they be instantiated only when needed, which is
13264 done in build_over_call. */
13267 /* Except that we do substitute default arguments under tsubst_lambda_expr,
13268 since the new op() won't have any associated template arguments for us
13269 to refer to later. */
13275 {
13276 /* We've instantiated a template before its default arguments
13277 have been parsed. This can happen for a nested template
13278 class, and is not an error unless we require the default
13279 argument in a call of this function. */
13280 remaining_arg_types =
13283 }
13284 else
13285 remaining_arg_types =
13287 }
13290 }
13292 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
13293 *not* handle the exception-specification for FNTYPE, because the
13294 initial substitution of explicitly provided template parameters
13295 during argument deduction forbids substitution into the
13296 exception-specification:
13298 [temp.deduct]
13300 All references in the function type of the function template to the
13301 corresponding template parameters are replaced by the specified tem-
13302 plate argument values. If a substitution in a template parameter or
13303 in the function type of the function template results in an invalid
13304 type, type deduction fails. [Note: The equivalent substitution in
13305 exception specifications is done only when the function is instanti-
13306 ated, at which point a program is ill-formed if the substitution
13307 results in an invalid type.] */
13309 static tree
13311 tree args,
13312 tsubst_flags_t complain,
13313 tree in_decl)
13314 {
13315 tree return_type;
13317 tree fntype;
13319 /* The TYPE_CONTEXT is not used for function/method types. */
13322 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
13323 failure. */
13327 {
13328 /* Substitute the argument types. */
13340 {
13341 /* DR 1207: 'this' is in scope in the trailing return type. */
13343 }
13345 /* Substitute the return type. */
13349 {
13352 }
13353 }
13354 else
13355 /* Substitute the return type. */
13360 /* DR 486 clarifies that creation of a function type with an
13361 invalid return type is a deduction failure. */
13364 {
13366 {
13369 else
13371 }
13373 }
13374 /* And DR 657. */
13379 {
13380 /* Substitute the argument types. */
13385 }
13387 /* Construct a new type node and return it. */
13389 {
13394 }
13395 else
13396 {
13398 /* Don't pick up extra function qualifiers from the basetype. */
13401 {
13402 /* [temp.deduct]
13404 Type deduction may fail for any of the following
13405 reasons:
13407 -- Attempting to create "pointer to member of T" when T
13408 is not a class type. */
13411 r);
13413 }
13418 }
13425 }
13427 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
13428 ARGS into that specification, and return the substituted
13429 specification. If there is no specification, return NULL_TREE. */
13431 static tree
13433 tree args,
13434 tsubst_flags_t complain,
13435 tree in_decl,
13437 {
13438 tree specs;
13439 tree new_specs;
13444 {
13445 /* A noexcept-specifier. */
13450 {
13451 /* Defer instantiation of noexcept-specifiers to avoid
13452 excessive instantiations (c++/49107). */
13455 {
13456 /* We already partially instantiated this member template,
13457 so combine the new args with the old. */
13462 }
13463 else
13464 {
13467 }
13468 }
13469 else
13470 new_specs = tsubst_copy_and_build
13474 }
13476 {
13479 else
13481 {
13482 tree spec;
13487 {
13488 /* Expand the pack expansion type. */
13491 in_decl);
13497 else
13498 {
13499 /* We're substituting into a member template, so
13500 we got a TYPE_PACK_EXPANSION back. Add that
13501 expansion and move on. */
13505 expanded_specs,
13506 complain);
13509 }
13510 }
13513 {
13516 else
13521 complain);
13522 }
13525 }
13526 }
13528 }
13530 /* Take the tree structure T and replace template parameters used
13531 therein with the argument vector ARGS. IN_DECL is an associated
13532 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
13533 Issue error and warning messages under control of COMPLAIN. Note
13534 that we must be relatively non-tolerant of extensions here, in
13535 order to preserve conformance; if we allow substitutions that
13536 should not be allowed, we may allow argument deductions that should
13537 not succeed, and therefore report ambiguous overload situations
13538 where there are none. In theory, we could allow the substitution,
13539 but indicate that it should have failed, and allow our caller to
13540 make sure that the right thing happens, but we don't try to do this
13541 yet.
13543 This function is used for dealing with types, decls and the like;
13544 for expressions, use tsubst_expr or tsubst_copy. */
13546 tree
13548 {
13571 else
13576 /* Reuse typedefs. We need to do this to handle dependent attributes,
13577 such as attribute aligned. */
13580 {
13584 {
13585 /* DECL represents an alias template and we want to
13586 instantiate it. */
13590 }
13594 {
13598 }
13603 else
13604 /* The typedef is from a non-template context. */
13608 {
13610 r = cp_build_qualified_type_real
13614 }
13615 else
13616 {
13617 /* We don't have an instantiation yet, so drop the typedef. */
13622 }
13623 }
13640 {
13666 {
13672 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
13673 needed. */
13679 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
13680 with TREE_SIDE_EFFECTS that indicates this is not an integral
13681 constant expression. */
13684 {
13687 }
13690 }
13696 {
13702 /* Early in template argument deduction substitution, we don't
13703 want to reduce the level of 'auto', or it will be confused
13704 with a normal template parm in subsequent deduction. */
13716 {
13720 {
13721 /* See through ARGUMENT_PACK_SELECT arguments. */
13723 /* If the selected argument is an expansion E, that most
13724 likely means we were called from
13725 gen_elem_of_pack_expansion_instantiation during the
13726 substituting of pack an argument pack (which Ith
13727 element is a pack expansion, where I is
13728 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
13729 In this case, the Ith element resulting from this
13730 substituting is going to be a pack expansion, which
13731 pattern is the pattern of E. Let's return the
13732 pattern of E, and
13733 gen_elem_of_pack_expansion_instantiation will
13734 build the resulting pack expansion from it. */
13736 {
13737 /* Make sure we aren't throwing away arg info. */
13740 }
13741 }
13742 }
13747 {
13749 /* If ARG is an argument pack, we don't actually want to
13750 perform a substitution here, because substitutions
13751 for argument packs are only done
13752 element-by-element. We can get to this point when
13753 substituting the type of a non-type template
13754 parameter pack, when that type actually contains
13755 template parameter packs from an outer template, e.g.,
13757 template<typename... Types> struct A {
13758 template<Types... Values> struct B { };
13759 }; */
13763 {
13769 return cp_build_qualified_type_real
13771 }
13773 {
13774 /* We are processing a type constructed from a
13775 template template parameter. */
13786 /* Consider this code:
13788 template <template <class> class Template>
13789 struct Internal {
13790 template <class Arg> using Bind = Template<Arg>;
13791 };
13793 template <template <class> class Template, class Arg>
13794 using Instantiate = Template<Arg>; //#0
13796 template <template <class> class Template,
13797 class Argument>
13798 using Bind =
13799 Instantiate<Internal<Template>::template Bind,
13800 Argument>; //#1
13802 When #1 is parsed, the
13803 BOUND_TEMPLATE_TEMPLATE_PARM representing the
13804 parameter `Template' in #0 matches the
13805 UNBOUND_CLASS_TEMPLATE representing the argument
13806 `Internal<Template>::template Bind'; We then want
13807 to assemble the type `Bind<Argument>' that can't
13808 be fully created right now, because
13809 `Internal<Template>' not being complete, the Bind
13810 template cannot be looked up in that context. So
13811 we need to "store" `Bind<Argument>' for later
13812 when the context of Bind becomes complete. Let's
13813 store that in a TYPENAME_TYPE. */
13817 argvec),
13818 typename_type,
13819 complain);
13821 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
13822 are resolving nested-types in the signature of a
13823 member function templates. Otherwise ARG is a
13824 TEMPLATE_DECL and is the real template to be
13825 instantiated. */
13833 complain);
13834 return cp_build_qualified_type_real
13836 }
13839 else
13840 /* TEMPLATE_PARM_INDEX. */
13842 }
13845 /* This can happen during the attempted tsubst'ing in
13846 unify. This means that we don't yet have any information
13847 about the template parameter in question. */
13850 /* If we get here, we must have been looking at a parm for a
13851 more deeply nested template. Make a new version of this
13852 template parameter, but with a lower level. */
13854 {
13859 {
13861 r = cp_build_qualified_type_real
13865 }
13872 /* Break infinite recursion when substituting the constraints
13874 else
13875 {
13886 {
13887 /* Propagate constraints on placeholders. */
13892 {
13896 }
13897 }
13900 /* We have reduced the level of the template
13901 template parameter, but not the levels of its
13902 template parameters, so canonical_type_parameter
13903 will not be able to find the canonical template
13904 template parameter for this level. Thus, we
13905 require structural equality checking to compare
13906 TEMPLATE_TEMPLATE_PARMs. */
13910 else
13914 {
13916 /* We might need to substitute into the types of non-type
13917 template parameters. */
13929 }
13930 }
13934 /* OK, now substitute the type of the non-type parameter. We
13935 couldn't do it earlier because it might be an auto parameter,
13936 and we wouldn't need to if we had an argument. */
13945 }
13948 }
13951 {
13959 {
13963 }
13966 {
13970 }
13973 {
13977 }
13983 }
13986 /* We should never be tsubsting a binfo. */
13990 /* A vector of template arguments. */
13996 {
14000 /* [temp.deduct]
14002 Type deduction may fail for any of the following
14003 reasons:
14005 -- Attempting to create a pointer to reference type.
14006 -- Attempting to create a reference to a reference type or
14007 a reference to void.
14009 Core issue 106 says that creating a reference to a reference
14010 during instantiation is no longer a cause for failure. We
14011 only enforce this check in strict C++98 mode. */
14015 {
14018 /* We keep track of the last time we issued this error
14019 message to avoid spewing a ton of messages during a
14020 single bad template instantiation. */
14023 {
14028 else
14031 }
14034 }
14038 {
14040 {
14043 type);
14044 else
14046 type);
14047 }
14049 }
14051 {
14055 }
14057 /* In C++0x, during template argument substitution, when there is an
14058 attempt to create a reference to a reference type, reference
14059 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
14061 "If a template-argument for a template-parameter T names a type
14062 that is a reference to a type A, an attempt to create the type
14063 'lvalue reference to cv T' creates the type 'lvalue reference to
14064 A,' while an attempt to create the type type rvalue reference to
14065 cv T' creates the type T"
14066 */
14067 r = cp_build_reference_type
14070 else
14075 /* Will this ever be needed for TYPE_..._TO values? */
14079 }
14081 {
14084 {
14085 /* [temp.deduct]
14087 Type deduction may fail for any of the following
14088 reasons:
14090 -- Attempting to create "pointer to member of T" when T
14091 is not a class type. */
14095 }
14097 {
14101 }
14103 {
14107 }
14110 {
14111 /* The type of the implicit object parameter gets its
14112 cv-qualifiers from the FUNCTION_TYPE. */
14113 tree memptr;
14114 tree method_type
14119 complain);
14120 }
14121 else
14124 complain);
14125 }
14128 {
14129 tree fntype;
14130 tree specs;
14135 /* Substitute the exception specification. */
14143 }
14145 {
14150 /* As an optimization, we avoid regenerating the array type if
14151 it will obviously be the same as T. */
14155 /* These checks should match the ones in create_array_type_for_decl.
14157 [temp.deduct]
14159 The deduction may fail for any of the following reasons:
14161 -- Attempting to create an array with an element type that
14162 is void, a function type, or a reference type, or [DR337]
14163 an abstract class type. */
14169 {
14173 }
14181 {
14184 }
14187 }
14190 {
14202 {
14206 }
14208 {
14209 /* Normally, make_typename_type does not require that the CTX
14210 have complete type in order to allow things like:
14212 template <class T> struct S { typename S<T>::X Y; };
14214 But, such constructs have already been resolved by this
14215 point, so here CTX really should have complete type, unless
14216 it's a partial instantiation. */
14219 {
14223 }
14224 }
14231 {
14234 }
14237 {
14239 {
14243 else
14245 }
14247 {
14251 else
14253 }
14254 }
14256 return cp_build_qualified_type_real
14258 }
14261 {
14273 }
14276 {
14277 tree type;
14293 complain);
14294 }
14297 {
14298 tree type;
14309 {
14311 {
14315 }
14318 }
14329 else
14330 {
14334 /* In a template ~id could be either a complement expression
14335 or an unqualified-id naming a destructor; if instantiating
14336 it produces an expression, it's not an id-expression or
14337 member access. */
14340 }
14345 }
14348 {
14352 }
14356 {
14357 tree r;
14361 else
14369 }
14384 /* We should use one of the expression tsubsts for these codes. */
14390 }
14391 }
14393 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
14394 expression on the left-hand side of the "." or "->" operator. We
14395 only do the lookup if we had a dependent BASELINK. Otherwise we
14396 adjust it onto the instantiated heirarchy. */
14398 static tree
14401 {
14413 {
14420 }
14427 {
14433 /* Treat as-if non-dependent below. */
14438 {
14444 }
14448 }
14449 else
14450 {
14452 /* We're going to overwrite pieces below, make a duplicate. */
14454 }
14456 /* If lookup found a single function, mark it as used at this point.
14457 (If lookup found multiple functions the one selected later by
14458 overload resolution will be marked as used at that point.) */
14464 {
14465 /* Add back the template arguments, if present. */
14470 /* Update the conversion operator type. */
14472 }
14478 {
14480 qualifying_scope,
14481 object_type);
14483 /* We need to call adjust_result_of_qualified_name_lookup in case the
14484 destructor names a base class, but we unset BASELINK_QUALIFIED_P
14485 so that we still get virtual function binding. */
14487 }
14490 }
14492 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
14493 true if the qualified-id will be a postfix-expression in-and-of
14494 itself; false if more of the postfix-expression follows the
14495 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
14496 of "&". */
14498 static tree
14502 {
14503 tree expr;
14504 tree scope;
14505 tree name;
14507 tree template_args;
14512 /* Figure out what name to look up. */
14515 {
14525 }
14526 else
14527 {
14530 }
14532 /* Substitute into the qualifying scope. When there are no ARGS, we
14533 are just trying to simplify a non-dependent expression. In that
14534 case the qualifying scope may be dependent, and, in any case,
14535 substituting will not help. */
14538 {
14541 }
14542 else
14546 {
14553 }
14556 {
14558 {
14559 /* A BIT_NOT_EXPR is used to represent a destructor. */
14561 {
14565 }
14566 else
14569 }
14570 else
14574 {
14576 {
14580 }
14582 }
14583 }
14586 {
14588 scope);
14589 /* Remember that there was a reference to this entity. */
14592 }
14595 {
14601 }
14604 {
14607 complain);
14608 else
14610 }
14616 {
14617 expr = (adjust_result_of_qualified_name_lookup
14619 expr = (finish_qualified_id_expr
14623 }
14625 /* Expressions do not generally have reference type. */
14627 /* However, if we're about to form a pointer-to-member, we just
14628 want the referenced member referenced. */
14636 }
14638 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
14639 initializer, DECL is the substituted VAR_DECL. Other arguments are as
14640 for tsubst. */
14642 static tree
14645 {
14652 {
14653 /* If we had an initializer but it
14654 instantiated to nothing,
14655 value-initialize the object. This will
14656 only occur when the initializer was a
14657 pack expansion where the parameter packs
14658 used in that expansion were of length
14659 zero. */
14661 complain);
14666 }
14669 }
14671 /* Like tsubst, but deals with expressions. This function just replaces
14672 template parms; to finish processing the resultant expression, use
14673 tsubst_copy_and_build or tsubst_expr. */
14675 static tree
14677 {
14679 tree r;
14687 {
14692 {
14693 /* We get here for a use of 'this' in an NSDMI. */
14697 /* This can happen for a parameter name used later in a function
14698 declaration (such as in a late-specified return type). Just
14699 make a dummy decl, since it's only used for its type. */
14702 /* Give it the template pattern as its context; its true context
14703 hasn't been instantiated yet and this is good enough for
14704 mangling. */
14706 }
14715 {
14716 tree enum_type;
14717 tree v;
14721 /* There is no need to substitute into namespace-scope
14722 enumerators. */
14725 /* If ARGS is NULL, then T is known to be non-dependent. */
14729 /* Unfortunately, we cannot just call lookup_name here.
14730 Consider:
14732 template <int I> int f() {
14733 enum E { a = I };
14734 struct S { void g() { E e = a; } };
14735 };
14737 When we instantiate f<7>::S::g(), say, lookup_name is not
14738 clever enough to find f<7>::a. */
14739 enum_type
14749 /* We didn't find the name. That should never happen; if
14750 name-lookup found it during preliminary parsing, we
14751 should find it again here during instantiation. */
14753 }
14758 {
14759 /* Check for a local specialization set up by
14760 tsubst_pack_expansion. */
14762 {
14766 }
14768 /* When retrieving a capture pack from a generic lambda, remove the
14769 lambda call op's own template argument list from ARGS. Only the
14770 template arguments active for the closure type should be used to
14771 retrieve the pack specialization. */
14777 /* Otherwise return the full NONTYPE_ARGUMENT_PACK that
14778 tsubst_decl put in the hash table. */
14780 }
14783 {
14784 tree ctx;
14789 {
14792 {
14796 }
14798 }
14799 }
14809 {
14812 {
14813 /* First try name lookup to find the instantiation. */
14816 {
14817 /* Make sure that the one we found is the one we want. */
14821 }
14825 else
14826 {
14827 /* This can happen for a variable used in a
14828 late-specified return type of a local lambda, or for a
14829 local static or constant. Building a new VAR_DECL
14830 should be OK in all those cases. */
14833 /* Avoid infinite recursion (79640). */
14836 {
14837 /* We can't call cp_finish_decl, so handle the
14838 initializer by hand. */
14853 }
14860 }
14861 /* Remember this for subsequent uses. */
14864 }
14865 }
14866 else
14876 /* An OVERLOAD will always be a non-dependent overload set; an
14877 overload set from function scope will just be represented with an
14878 IDENTIFIER_NODE, and from class scope with a BASELINK. */
14880 /* We must have marked any lookups as persistent. */
14896 {
14897 /* Template template argument like the following example need
14898 special treatment:
14900 template <template <class> class TT> struct C {};
14901 template <class T> struct D {
14902 template <class U> struct E {};
14903 C<E> c; // #1
14904 };
14905 D<int> d; // #2
14907 We are processing the template argument `E' in #1 for
14908 the template instantiation #2. Originally, `E' is a
14909 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
14910 have to substitute this with one having context `D<int>'. */
14914 {
14915 /* When rewriting a constructor into a deduction guide, a
14916 non-dependent name can become dependent, so memtmpl<args>
14917 becomes context::template memtmpl<args>. */
14921 }
14923 }
14924 else
14925 /* Ordinary template template argument. */
14930 {
14931 /* Handle location wrappers by substituting the wrapped node
14932 first, *then* reusing the resulting type. Doing the type
14933 first ensures that we handle template parameters and
14934 parameter pack expansions. */
14938 }
14948 {
14952 }
14957 {
14966 /* We only want to compute the number of arguments. */
14969 else
14976 {
14978 /* Set TREE_USED for the benefit of -Wunused. */
14982 }
14990 {
14995 else
15001 else
15004 }
15005 else
15007 }
15009 {
15017 }
15018 /* Fall through */
15034 {
15038 }
15041 {
15042 tree object;
15043 tree name;
15048 {
15052 }
15055 {
15065 }
15070 in_decl);
15071 else
15074 }
15112 {
15116 }
15119 {
15124 }
15127 {
15131 }
15134 {
15142 }
15148 {
15155 }
15158 {
15165 }
15168 {
15175 }
15178 {
15179 /* Substituted template arguments */
15188 }
15191 {
15211 }
15236 /* Fall through. */
15239 {
15242 }
15243 else
15247 /* This is handled by tsubst_copy_and_build. */
15251 {
15255 }
15258 /* We shouldn't have built any of these during initial template
15259 generation. Instead, they should be built during instantiation
15260 in response to the saved STMT_IS_FULL_EXPR_P setting. */
15264 {
15274 }
15292 {
15293 /* Instantiate any typedefs in the type. */
15298 }
15301 /* These can sometimes show up in a partial instantiation, but never
15302 involve template parms. */
15318 /* ??? There's no point in copying it for now, but maybe some
15319 day it will contain more information, such as a pointer back
15320 to the containing function, inlined copy or so. */
15324 /* We shouldn't get here, but keep going if !flag_checking. */
15328 }
15329 }
15331 /* Helper function for tsubst_omp_clauses, used for instantiation of
15332 OMP_CLAUSE_DECL of clauses. */
15334 static tree
15336 tree in_decl)
15337 {
15341 /* Handle an OpenMP array section represented as a TREE_LIST (or
15342 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15343 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15344 TREE_LIST. We can handle it exactly the same as an array section
15345 (purpose, value, and a chain), even though the nomenclature
15346 (low_bound, length, etc) is different. */
15348 {
15349 tree low_bound
15355 in_decl);
15364 }
15367 /* Undo convert_from_reference tsubst_expr could have called. */
15373 }
15375 /* Like tsubst_copy, but specifically for OpenMP clauses. */
15377 static tree
15380 {
15385 {
15391 {
15394 {
15400 }
15401 /* FALLTHRU */
15416 in_decl);
15448 {
15451 {
15458 }
15459 else
15461 }
15464 in_decl);
15470 in_decl);
15478 in_decl);
15480 {
15483 }
15488 else
15491 in_decl,
15515 }
15518 {
15528 /* tsubst_expr on SCOPE_REF results in returning
15529 finish_non_static_data_member result. Undo that here. */
15533 {
15538 {
15542 CASE_CONVERT:
15551 /* FALLTHRU */
15555 }
15556 }
15562 {
15565 {
15568 }
15569 }
15573 }
15574 }
15578 {
15583 {
15586 }
15587 }
15589 }
15591 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
15593 static tree
15595 tree in_decl)
15596 {
15597 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
15617 {
15620 else
15621 {
15625 }
15626 }
15631 #undef RECUR
15632 }
15634 /* Used to temporarily communicate the list of #pragma omp parallel
15635 clauses to #pragma omp for instantiation if they are combined
15636 together. */
15640 /* Substitute one OMP_FOR iterator. */
15642 static void
15647 {
15648 #define RECUR(NODE) \
15649 tsubst_expr ((NODE), args, complain, in_decl, \
15650 integral_constant_expression_p)
15657 {
15660 }
15666 {
15667 /* We need to jump through some hoops to handle declarations in the
15668 init-statement, since we might need to handle auto deduction,
15669 but we need to keep control of initialization. */
15673 }
15674 else
15675 {
15677 {
15680 {
15684 {
15688 CASE_CONVERT:
15696 {
15699 }
15700 /* FALLTHRU */
15704 }
15705 }
15706 }
15707 else
15709 }
15720 {
15722 {
15723 /* Declare the variable, but don't let that initialize it. */
15728 }
15733 {
15738 }
15739 else
15746 }
15749 {
15750 /* Declare and initialize the variable. */
15753 }
15755 {
15759 {
15761 {
15767 {
15770 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
15775 }
15778 {
15780 decl);
15782 }
15785 {
15787 decl);
15789 }
15790 else
15792 }
15795 }
15797 {
15802 {
15805 }
15806 }
15807 }
15810 {
15814 }
15815 else
15819 {
15830 {
15838 }
15839 else
15845 {
15851 }
15855 {
15863 }
15864 else
15870 }
15876 #undef RECUR
15877 }
15879 /* Helper function of tsubst_expr, find OMP_TEAMS inside
15880 of OMP_TARGET's body. */
15882 static tree
15884 {
15887 {
15896 }
15898 }
15900 /* Helper function for tsubst_expr. For decomposition declaration
15901 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
15902 also the corresponding decls representing the identifiers
15903 of the decomposition declaration. Return DECL if successful
15904 or error_mark_node otherwise, set *FIRST to the first decl
15905 in the list chained through DECL_CHAIN and *CNT to the number
15906 of such decls. */
15908 static tree
15912 {
15917 decl2
15922 {
15924 {
15927 }
15944 {
15947 }
15948 else
15950 }
15953 }
15955 /* Like tsubst_copy for expressions, etc. but also does semantic
15956 processing. */
15958 tree
15961 {
15962 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
15963 #define RECUR(NODE) \
15964 tsubst_expr ((NODE), args, complain, in_decl, \
15965 integral_constant_expression_p)
15968 tree r;
15969 location_t loc;
15981 {
15983 {
15984 tree_stmt_iterator i;
15988 }
16003 else
16013 {
16015 tree init;
16021 {
16031 else
16033 }
16035 {
16036 /* Don't build up decls for a variadic capture proxy, we'll
16037 instantiate the elements directly as needed. */
16039 }
16042 {
16043 /* We're in tsubst_lambda_expr, we've already inserted a new
16044 capture proxy, so look it up and register it. */
16050 }
16053 /* Don't copy the old closure; we'll create a new one in
16054 tsubst_lambda_expr. */
16056 else
16057 {
16061 {
16062 /* By marking the declaration as instantiated, we avoid
16063 trying to instantiate it. Since instantiate_decl can't
16064 handle local variables, and since we've already done
16065 all that needs to be done, that's the right thing to
16066 do. */
16071 /* Anonymous aggregates are a special case. */
16074 {
16077 {
16081 }
16083 }
16089 {
16094 }
16095 else
16096 {
16101 {
16102 /* For __PRETTY_FUNCTION__ we have to adjust the
16103 initializer. */
16107 }
16108 else
16112 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
16117 {
16119 tree first;
16120 tree ndecl
16128 }
16129 else
16131 }
16132 }
16133 }
16136 }
16146 {
16150 }
16155 {
16162 const unsigned short unroll
16165 {
16167 tree first;
16172 }
16173 else
16180 }
16187 {
16191 }
16197 {
16201 }
16214 else
16215 {
16222 }
16228 {
16237 }
16245 else
16253 else
16274 {
16281 }
16285 {
16287 tree label;
16294 }
16300 /* Computed goto's must be tsubst'd into. On the other hand,
16301 non-computed gotos must not be; the identifier in question
16302 will have no binding. */
16304 else
16310 {
16326 }
16331 {
16336 }
16337 else
16338 {
16343 else
16350 else
16356 else
16358 }
16362 {
16366 {
16368 /* Prevent instantiate_decl from trying to instantiate
16369 this variable. We've already done all that needs to be
16370 done. */
16373 }
16378 }
16384 {
16385 /* Local classes are not independent templates; they are
16386 instantiated along with their containing function. And this
16387 way we don't have to deal with pushing out of one local class
16388 to instantiate a member of another local class. */
16389 /* Closures are handled by the LAMBDA_EXPR. */
16399 }
16403 {
16404 tree condition;
16407 condition =
16409 args,
16418 }
16424 in_decl);
16459 {
16472 in_decl);
16474 {
16481 }
16493 integral_constant_expression_p);
16504 else
16505 {
16513 }
16517 }
16522 /* FALLTHRU */
16529 in_decl);
16546 in_decl);
16557 {
16560 {
16561 /* For combined target teams, ensure the num_teams and
16562 thread_limit clause expressions are evaluated on the host,
16563 before entering the target construct. */
16564 tree c;
16570 {
16579 OMP_CLAUSE_FIRSTPRIVATE);
16583 }
16584 }
16585 }
16645 {
16650 {
16653 }
16659 }
16660 else
16661 {
16668 {
16671 }
16674 {
16679 {
16682 }
16688 }
16689 else
16690 {
16694 }
16697 }
16701 {
16707 {
16711 {
16716 }
16720 }
16721 else
16722 {
16727 }
16728 }
16732 {
16736 }
16749 /* If the first operand was a statement, we're done with it. */
16753 complain));
16767 integral_constant_expression_p));
16768 }
16771 out:
16774 #undef RECUR
16775 #undef RETURN
16776 }
16778 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
16779 function. For description of the body see comment above
16780 cp_parser_omp_declare_reduction_exprs. */
16782 static void
16784 {
16790 tree_stmt_iterator tsi;
16801 {
16820 }
16822 {
16842 }
16843 }
16845 /* T is a postfix-expression that is not being used in a function
16846 call. Return the substituted version of T. */
16848 static tree
16850 tsubst_flags_t complain,
16851 tree in_decl)
16852 {
16856 else
16862 }
16864 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
16865 instantiation context. Instantiating a pack expansion containing a lambda
16866 might result in multiple lambdas all based on the same lambda in the
16867 template. */
16869 tree
16871 {
16885 else
16893 {
16905 else
16910 {
16919 }
16920 else
16921 {
16927 }
16928 }
16932 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
16950 else
16951 {
16952 /* Fix the type of 'this'. */
16958 {
16962 }
16963 else
16964 {
16968 }
16970 /* Let finish_function set this. */
16991 /* The capture list was built up in reverse order; fix that now. */
16998 }
17005 }
17007 /* Like tsubst but deals with expressions and performs semantic
17008 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
17010 tree
17012 tree args,
17013 tsubst_flags_t complain,
17014 tree in_decl,
17017 {
17018 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
17019 #define RECUR(NODE) \
17020 tsubst_copy_and_build (NODE, args, complain, in_decl, \
17022 integral_constant_expression_p)
17025 location_t loc;
17034 /* N3276 decltype magic only applies to calls at the top level or on the
17035 right side of a comma. */
17040 {
17043 /* Fall through. */
17045 {
17046 tree decl;
17047 cp_id_kind idk;
17052 {
17055 }
17057 /* Look up the name. */
17060 /* By convention, expressions use ERROR_MARK_NODE to indicate
17061 failure, not NULL_TREE. */
17067 integral_constant_expression_p,
17075 input_location);
17079 {
17083 }
17085 }
17088 {
17089 tree object;
17099 {
17104 }
17110 {
17113 }
17114 else
17121 else
17123 }
17126 {
17130 {
17131 /* A type conversion to reference type will be enclosed in
17132 such an indirect ref, but the substitution of the cast
17133 will have also added such an indirect ref. */
17135 }
17136 else
17144 }
17147 {
17151 }
17154 {
17158 {
17163 }
17165 /* We'll pass this to convert_nontype_argument again, we don't need
17166 to actually perform any conversion here. */
17172 flags));
17173 }
17176 {
17180 }
17187 {
17188 tree type;
17194 {
17199 }
17206 {
17224 }
17227 }
17261 else
17263 in_decl);
17298 {
17305 tree r = build_x_binary_op
17307 op0,
17309 ? ERROR_MARK
17311 op1,
17313 ? ERROR_MARK
17321 }
17324 {
17328 }
17344 /* Fall through */
17347 {
17348 tree r;
17354 {
17355 /* When there are no ARGS, we are trying to evaluate a
17356 non-dependent expression from the parser. Trying to do
17357 the substitutions may not work. */
17360 }
17361 else
17362 {
17367 else
17370 /*integral_constant_expression_p=*/
17374 }
17378 else
17382 {
17384 {
17386 {
17390 }
17391 else
17395 }
17397 }
17399 }
17402 {
17412 }
17428 {
17432 tree r = build_x_modify_expr
17435 /* TREE_NO_WARNING must be set if either the expression was
17436 parenthesized or it uses an operator such as >>= rather
17437 than plain assignment. In the former case, it was already
17438 set and must be copied. In the latter case,
17439 build_x_modify_expr sets it and it must not be reset
17440 here. */
17445 }
17450 /* Remember that there was a reference to this entity. */
17457 {
17462 tree ret;
17466 else
17467 {
17471 }
17473 /* If there was an initializer in the original tree, but it
17474 instantiated to an empty list, then we should pass a
17475 non-NULL empty vector to tell build_new that it was an
17476 empty initializer() rather than no initializer. This can
17477 only happen when the initializer is a pack expansion whose
17478 parameter packs are of length zero. */
17481 else
17482 {
17486 else
17487 {
17490 }
17491 }
17497 complain);
17505 }
17508 {
17514 complain));
17515 }
17518 {
17522 integral_constant_expression_p);
17524 op0,
17527 }
17530 {
17531 tree function;
17536 tree ret;
17539 /* Internal function with no arguments. */
17543 /* When we parsed the expression, we determined whether or
17544 not Koenig lookup should be performed. */
17547 {
17550 }
17552 {
17557 }
17559 {
17560 /* Do nothing; calling tsubst_copy_and_build on an identifier
17561 would incorrectly perform unqualified lookup again.
17563 Note that we can also have an IDENTIFIER_NODE if the earlier
17564 unqualified lookup found a member function; in that case
17565 koenig_p will be false and we do want to do the lookup
17566 again to find the instantiated member function.
17568 FIXME but doing that causes c++/15272, so we need to stop
17569 using IDENTIFIER_NODE in that situation. */
17571 }
17572 else
17573 {
17575 {
17581 }
17582 else
17587 /* Avoid error about taking the address of a constructor. */
17591 in_decl,
17593 integral_constant_expression_p);
17597 }
17602 {
17607 else
17608 {
17609 /* Expand the pack expansion and push each entry onto
17610 CALL_ARGS. */
17613 {
17618 {
17623 }
17624 }
17625 else
17626 {
17627 /* A partial substitution. Add one entry. */
17629 }
17630 }
17631 }
17633 /* We do not perform argument-dependent lookup if normal
17634 lookup finds a non-function, in accordance with the
17635 expected resolution of DR 218. */
17638 /* If lookup found a member function, the Koenig lookup is
17639 not appropriate, even if an unqualified-name was used
17640 to denote the function. */
17643 /* Only do this when substitution turns a dependent call
17644 into a non-dependent call. */
17652 {
17654 {
17655 /* For backwards compatibility and good diagnostics, try
17656 the unqualified lookup again if we aren't in SFINAE
17657 context. */
17658 tree unq = (tsubst_copy_and_build
17660 integral_constant_expression_p));
17662 {
17665 }
17668 {
17669 /* In a lambda fn, we have to be careful to not
17670 introduce new this captures. Legacy code can't
17671 be using lambdas anyway, so it's ok to be
17672 stricter. */
17677 "and no declarations were found by "
17678 "argument-dependent lookup at the point "
17685 else
17689 {
17700 {
17702 input_location);
17704 "declarations in dependent base %qT are "
17710 else
17714 }
17715 else
17717 "%qD declared here, later in the "
17720 {
17723 }
17724 }
17727 }
17728 }
17730 {
17735 }
17736 }
17738 /* Remember that there was a reference to this entity. */
17742 {
17745 }
17747 /* Put back tf_decltype for the actual call. */
17752 {
17756 {
17758 "wrong number of arguments to "
17761 }
17762 else
17764 input_location),
17769 /* Unsupported internal function with arguments. */
17771 }
17774 complain);
17776 {
17791 complain);
17792 else
17793 ret = (build_new_method_call
17798 complain));
17799 }
17800 else
17803 koenig_p,
17804 complain);
17809 {
17815 {
17821 {
17823 /* The thunk location is not interesting. */
17825 }
17826 }
17827 }
17830 }
17833 {
17839 {
17841 {
17846 }
17847 else
17848 {
17853 }
17855 }
17856 else
17857 {
17860 }
17865 }
17868 {
17873 input_location));
17874 }
17877 {
17885 {
17886 /* We have pack expansions, so expand those and
17887 create a new list out of it. */
17890 tree chain;
17893 /* Expand the argument expressions. */
17901 /* Build the rest of the list. */
17906 /* Determine the number of arguments. */
17908 {
17911 }
17914 else
17915 {
17916 /* Since we only performed a partial substitution into
17917 the argument pack, we only RETURN (a single list
17918 node. */
17925 }
17927 /* Convert the argument vectors into a TREE_LIST */
17930 {
17931 /* Grab the Ith values. */
17932 i--;
17935 value
17939 /* Build the list (backwards). */
17941 }
17944 }
17960 }
17963 {
17964 tree object;
17965 tree object_type;
17966 tree member;
17967 tree r;
17971 /* Remember that there was a reference to this entity. */
17982 else
17988 {
17993 }
17997 {
17999 {
18004 {
18007 }
18009 {
18014 }
18015 }
18016 }
18019 {
18020 /* Lookup the template functions now that we know what the
18021 scope is. */
18029 {
18032 args);
18033 member = (adjust_result_of_qualified_name_lookup
18035 object_type));
18036 }
18037 else
18038 {
18040 input_location);
18042 }
18043 }
18047 {
18049 {
18053 else
18056 }
18058 }
18062 complain);
18066 }
18073 {
18081 tree r;
18086 /* digest_init will do the wrong thing if we let it. */
18090 /* We do not want to process the index of aggregate
18091 initializers as they are identifier nodes which will be
18092 looked up by digest_init. */
18098 {
18100 /* An identifier index is looked up in the type
18101 being initialized, not the current scope. */
18106 {
18107 /* Substitute into the pack expansion. */
18109 in_decl);
18113 ;
18115 /* Just move the argument into place. */
18117 else
18118 {
18119 /* Update the length of the final CONSTRUCTOR
18120 arguments vector, and note that we will need to
18121 copy.*/
18124 }
18125 }
18126 else
18128 }
18131 {
18136 {
18138 {
18143 }
18144 else
18146 }
18147 }
18153 {
18158 }
18162 }
18165 {
18168 {
18171 }
18172 else
18173 {
18176 }
18177 }
18183 {
18184 /* We don't build decls for an instantiation of a
18185 variadic capture proxy, we instantiate the elements
18186 when needed. */
18189 }
18190 /* Fall through */
18193 {
18195 /* ??? We're doing a subset of finish_id_expression here. */
18197 && !processing_template_decl
18198 && !cp_unevaluated_operand
18201 {
18203 /* Replace an evaluated use of the thread_local variable with
18204 a call to its wrapper. */
18206 }
18211 /* If the original type was a reference, we'll be wrapped in
18212 the appropriate INDIRECT_REF. */
18215 }
18218 {
18222 }
18225 {
18226 tree object_ptr
18233 }
18240 {
18251 }
18254 {
18260 integral_constant_expression_p);
18264 /* If the resulting list of expression statement is empty,
18265 fold it further into void_node. */
18270 }
18273 {
18277 }
18280 /* We can get here for a constant initializer of non-dependent type.
18281 FIXME stop folding in cp_parser_initializer_clause. */
18282 {
18284 complain);
18286 }
18290 integral_constant_expression_p));
18296 {
18301 complain));
18302 }
18309 /* We should only see these for location wrapper nodes, or within
18310 instantiate_non_dependent_expr (when args is NULL_TREE). */
18315 /* fallthrough. */
18318 /* Handle Objective-C++ constructs, if appropriate. */
18319 {
18320 tree subst
18325 }
18327 }
18329 #undef RECUR
18330 #undef RETURN
18331 out:
18334 }
18336 /* Verify that the instantiated ARGS are valid. For type arguments,
18337 make sure that the type's linkage is ok. For non-type arguments,
18338 make sure they are constants if they are integral or enumerations.
18339 Emit an error under control of COMPLAIN, and return TRUE on error. */
18341 static bool
18343 {
18347 {
18357 }
18359 {
18360 /* [basic.link]: A name with no linkage (notably, the name
18361 of a class or enumeration declared in a local scope)
18362 shall not be used to declare an entity with linkage.
18363 This implies that names with no linkage cannot be used as
18364 template arguments
18366 DR 757 relaxes this restriction for C++0x. */
18371 {
18372 /* DR 488 makes use of a type with no linkage cause
18373 type deduction to fail. */
18375 {
18378 else
18381 }
18383 }
18384 /* In order to avoid all sorts of complications, we do not
18385 allow variably-modified types as template arguments. */
18387 {
18391 }
18392 }
18393 /* Class template and alias template arguments should be OK. */
18395 ;
18396 /* A non-type argument of integral or enumerated type must be a
18397 constant. */
18402 {
18406 }
18408 }
18410 static bool
18412 {
18417 {
18420 }
18424 }
18426 /* We're out of SFINAE context now, so generate diagnostics for the access
18427 errors we saw earlier when instantiating D from TMPL and ARGS. */
18429 static void
18431 {
18443 }
18445 /* Instantiate the indicated variable, function, or alias template TMPL with
18446 the template arguments in TARG_PTR. */
18448 static tree
18450 {
18452 tree fndecl;
18453 tree gen_tmpl;
18454 tree spec;
18462 /* If this function is a clone, handle it specially. */
18464 {
18465 tree spec;
18466 tree clone;
18468 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
18469 DECL_CLONED_FUNCTION. */
18475 /* Look for the clone. */
18479 /* We should always have found the clone by now. */
18482 }
18487 /* Check to see if we already have this specialization. */
18491 /* targ_ptr only has the innermost template args, so add the outer ones
18492 from tmpl, which could be either a partial instantiation or gen_tmpl (in
18493 the case of a non-dependent call within a template definition). */
18494 targ_ptr = (add_outermost_template_args
18496 targ_ptr));
18498 /* It would be nice to avoid hashing here and then again in tsubst_decl,
18499 but it doesn't seem to be on the hot path. */
18508 {
18510 {
18514 }
18516 }
18519 complain))
18522 /* We are building a FUNCTION_DECL, during which the access of its
18523 parameters and return types have to be checked. However this
18524 FUNCTION_DECL which is the desired context for access checking
18525 is not built yet. We solve this chicken-and-egg problem by
18526 deferring all checks until we have the FUNCTION_DECL. */
18529 /* Instantiation of the function happens in the context of the function
18530 template, not the context of the overload resolution we're doing. */
18532 /* If there are dependent arguments, e.g. because we're doing partial
18533 ordering, make sure processing_template_decl stays set. */
18537 {
18541 }
18547 {
18548 /* We need to determine if we're using a partial or explicit
18549 specialization now, because the type of the variable could be
18550 different. */
18556 {
18561 }
18562 }
18564 /* Substitute template parameters to obtain the specialization. */
18572 {
18575 }
18577 /* The DECL_TI_TEMPLATE should always be the immediate parent
18578 template, not the most general template. */
18582 /* Now we know the specialization, compute access previously
18583 deferred. Do no access control for inheriting constructors,
18584 as we already checked access for the inherited constructor. */
18587 {
18592 }
18595 /* If we've just instantiated the main entry point for a function,
18596 instantiate all the alternate entry points as well. We do this
18597 by cloning the instantiation of the main entry point, not by
18598 instantiating the template clones. */
18603 {
18605 {
18606 /* Remember to reinstantiate when we're out of SFINAE so the user
18607 can see the errors. */
18609 }
18611 }
18613 }
18615 /* Wrapper for instantiate_template_1. */
18617 tree
18619 {
18620 tree ret;
18625 }
18627 /* Instantiate the alias template TMPL with ARGS. Also push a template
18628 instantiation level, which instantiate_template doesn't do because
18629 functions and variables have sufficient context established by the
18630 callers. */
18632 static tree
18634 {
18641 {
18644 }
18646 args =
18654 /* We can't free this if a pending_template entry or last_error_tinst_level
18655 is pointing at it. */
18661 }
18663 /* PARM is a template parameter pack for FN. Returns true iff
18664 PARM is used in a deducible way in the argument list of FN. */
18666 static bool
18668 {
18671 {
18673 tree packs;
18679 {
18680 /* The template parameter pack is used in a function parameter
18681 pack. If this is the end of the parameter list, the
18682 template parameter pack is deducible. */
18685 else
18686 /* Otherwise, not. Well, it could be deduced from
18687 a non-pack parameter, but doing so would end up with
18688 a deduction mismatch, so don't bother. */
18690 }
18691 }
18692 /* The template parameter pack isn't used in any function parameter
18693 packs, but it might be used deeper, e.g. tuple<Args...>. */
18695 }
18697 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
18698 NARGS elements of the arguments that are being used when calling
18699 it. TARGS is a vector into which the deduced template arguments
18700 are placed.
18702 Returns either a FUNCTION_DECL for the matching specialization of FN or
18703 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
18704 true, diagnostics will be printed to explain why it failed.
18706 If FN is a conversion operator, or we are trying to produce a specific
18707 specialization, RETURN_TYPE is the return type desired.
18709 The EXPLICIT_TARGS are explicit template arguments provided via a
18710 template-id.
18712 The parameter STRICT is one of:
18714 DEDUCE_CALL:
18715 We are deducing arguments for a function call, as in
18716 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
18717 deducing arguments for a call to the result of a conversion
18718 function template, as in [over.call.object].
18720 DEDUCE_CONV:
18721 We are deducing arguments for a conversion function, as in
18722 [temp.deduct.conv].
18724 DEDUCE_EXACT:
18725 We are deducing arguments when doing an explicit instantiation
18726 as in [temp.explicit], when determining an explicit specialization
18727 as in [temp.expl.spec], or when taking the address of a function
18728 template, as in [temp.deduct.funcaddr]. */
18730 tree
18732 tree explicit_targs,
18733 tree targs,
18736 tree return_type,
18737 unification_kind_t strict,
18741 {
18742 tree parms;
18743 tree fntype;
18756 tree tinst;
18762 full_targs = (add_outermost_template_args
18764 targs));
18769 /* In C++0x, it's possible to have a function template whose type depends
18770 on itself recursively. This is most obvious with decltype, but can also
18771 occur with enumeration scope (c++/48969). So we need to catch infinite
18772 recursion and reject the substitution at deduction time; this function
18773 will return error_mark_node for any repeated substitution.
18775 This also catches excessive recursion such as when f<N> depends on
18776 f<N-1> across all integers, and returns error_mark_node for all the
18777 substitutions back up to the initial one.
18779 This is, of course, not reentrant. */
18789 {
18790 /* [temp.deduct]
18792 The specified template arguments must match the template
18793 parameters in kind (i.e., type, nontype, template), and there
18794 must not be more arguments than there are parameters;
18795 otherwise type deduction fails.
18797 Nontype arguments must match the types of the corresponding
18798 nontype template parameters, or must be convertible to the
18799 types of the corresponding nontype parameters as specified in
18800 _temp.arg.nontype_, otherwise type deduction fails.
18802 All references in the function type of the function template
18803 to the corresponding template parameters are replaced by the
18804 specified template argument values. If a substitution in a
18805 template parameter or in the function type of the function
18806 template results in an invalid type, type deduction fails. */
18817 explicit_targs);
18819 /* Adjust any explicit template arguments before entering the
18820 substitution context. */
18821 explicit_targs
18823 complain,
18829 /* Substitute the explicit args into the function type. This is
18830 necessary so that, for instance, explicitly declared function
18831 arguments can match null pointed constants. If we were given
18832 an incomplete set of explicit args, we must not do semantic
18833 processing during substitution as we could create partial
18834 instantiations. */
18836 {
18841 /* Dig out the actual parm. */
18844 {
18847 }
18849 {
18852 }
18855 /* No explicit argument for this template parameter. */
18859 {
18860 /* Mark the argument pack as "incomplete". We could
18861 still deduce more arguments during unification.
18862 We remove this mark in type_unification_real. */
18864 {
18868 }
18870 /* We have some incomplete argument packs. */
18872 }
18873 }
18877 {
18880 }
18883 /* Ignore any access checks; we'll see them again in
18884 instantiate_template and they might have the wrong
18885 access path at this point. */
18897 /* Place the explicitly specified arguments in TARGS. */
18901 }
18903 /* Never do unification on the 'this' parameter. */
18907 {
18908 /* We're deducing for a call to the result of a template conversion
18909 function. The parms we really want are in return_type. */
18913 }
18915 {
18924 }
18926 /* We allow incomplete unification without an error message here
18927 because the standard doesn't seem to explicitly prohibit it. Our
18928 callers must be ready to deal with unification failures in any
18929 event. */
18932 /* If we aren't explaining yet, push tinst context so we can see where
18933 any errors (e.g. from class instantiations triggered by instantiation
18934 of default template arguments) come from. If we are explaining, this
18935 context is redundant. */
18937 {
18940 }
18942 /* type_unification_real will pass back any access checks from default
18943 template argument substitution. */
18955 /* Now that we have bindings for all of the template arguments,
18956 ensure that the arguments deduced for the template template
18957 parameters have compatible template parameter lists. We cannot
18958 check this property before we have deduced all template
18959 arguments, because the template parameter types of a template
18960 template parameter might depend on prior template parameters
18961 deduced after the template template parameter. The following
18962 ill-formed example illustrates this issue:
18964 template<typename T, template<T> class C> void f(C<5>, T);
18966 template<int N> struct X {};
18968 void g() {
18969 f(X<5>(), 5l); // error: template argument deduction fails
18970 }
18972 The template parameter list of 'C' depends on the template type
18973 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
18974 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
18975 time that we deduce 'C'. */
18978 {
18981 }
18983 /* All is well so far. Now, check:
18985 [temp.deduct]
18987 When all template arguments have been deduced, all uses of
18988 template parameters in nondeduced contexts are replaced with
18989 the corresponding deduced argument values. If the
18990 substitution results in an invalid type, as described above,
18991 type deduction fails. */
18994 {
18997 }
18999 /* Also collect access checks from the instantiation. */
19012 /* Now perform any access checks encountered during substitution. */
19019 /* If we're looking for an exact match, check that what we got
19020 is indeed an exact match. It might not be if some template
19021 parameters are used in non-deduced contexts. But don't check
19022 for an exact match if we have dependent template arguments;
19023 in that case we're doing partial ordering, and we already know
19024 that we have two candidates that will provide the actual type. */
19026 {
19030 tree sarg
19036 {
19040 }
19041 }
19043 /* After doing deduction with the inherited constructor, actually return an
19044 instantiation of the inheriting constructor. */
19050 fail:
19053 {
19055 /* Reset once we're all the way out. */
19057 }
19059 /* We can't free this if a pending_template entry or last_error_tinst_level
19060 is pointing at it. */
19066 }
19068 /* Adjust types before performing type deduction, as described in
19069 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
19070 sections are symmetric. PARM is the type of a function parameter
19071 or the return type of the conversion function. ARG is the type of
19072 the argument passed to the call, or the type of the value
19073 initialized with the result of the conversion function.
19074 ARG_EXPR is the original argument expression, which may be null. */
19076 static int
19080 tree arg_expr)
19081 {
19085 {
19090 /* Swap PARM and ARG throughout the remainder of this
19091 function; the handling is precisely symmetric since PARM
19092 will initialize ARG rather than vice versa. */
19097 /* Core issue #873: Do the DR606 thing (see below) for these cases,
19098 too, but here handle it by stripping the reference from PARM
19099 rather than by adding it to ARG. */
19107 /* Nothing else to do in this case. */
19112 }
19115 {
19116 /* [temp.deduct.call]
19118 If P is not a reference type:
19120 --If A is an array type, the pointer type produced by the
19121 array-to-pointer standard conversion (_conv.array_) is
19122 used in place of A for type deduction; otherwise,
19124 --If A is a function type, the pointer type produced by
19125 the function-to-pointer standard conversion
19126 (_conv.func_) is used in place of A for type deduction;
19127 otherwise,
19129 --If A is a cv-qualified type, the top level
19130 cv-qualifiers of A's type are ignored for type
19131 deduction. */
19136 else
19138 }
19140 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
19141 reference to a cv-unqualified template parameter that does not represent a
19142 template parameter of a class template (during class template argument
19143 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
19144 an lvalue, the type "lvalue reference to A" is used in place of A for type
19145 deduction. */
19152 /* try_one_overload doesn't provide an arg_expr, but
19153 functions are always lvalues. */
19157 /* [temp.deduct.call]
19159 If P is a cv-qualified type, the top level cv-qualifiers
19160 of P's type are ignored for type deduction. If P is a
19161 reference type, the type referred to by P is used for
19162 type deduction. */
19165 {
19168 }
19170 /* DR 322. For conversion deduction, remove a reference type on parm
19171 too (which has been swapped into ARG). */
19176 }
19178 /* Subroutine of unify_one_argument. PARM is a function parameter of a
19179 template which does contain any deducible template parameters; check if
19180 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
19181 unify_one_argument. */
19183 static int
19186 {
19187 tree type;
19191 else
19198 {
19202 }
19204 {
19209 }
19213 else
19215 }
19219 /* Returns true iff the expression EXPR is one from which a template
19220 argument can be deduced. In other words, if it's an undecorated
19221 use of a template non-type parameter. */
19223 static bool
19225 {
19226 /* Strip implicit conversions. */
19230 }
19232 /* Returns true iff the array domain DOMAIN uses a template parameter in a
19233 deducible way; that is, if it has a max value of <PARM> - 1. */
19235 static bool
19237 {
19246 }
19248 /* Returns true iff the template arguments ARGS use a template parameter
19249 in a deducible way. */
19251 static bool
19253 {
19255 {
19260 else
19261 {
19268 else
19270 }
19273 }
19275 }
19277 /* Returns true iff TYPE contains any deducible references to template
19278 parameters, as per 14.8.2.5. */
19280 static bool
19282 {
19286 /* T
19287 cv-list T
19288 TT<T>
19289 TT<i>
19290 TT<> */
19295 /* T*
19296 T&
19297 T&& */
19301 /* T[integer-constant ]
19302 type [i] */
19307 /* T type ::*
19308 type T::*
19309 T T::*
19310 T (type ::*)()
19311 type (T::*)()
19312 type (type ::*)(T)
19313 type (T::*)(T)
19314 T (type ::*)(T)
19315 T (T::*)()
19316 T (T::*)(T) */
19319 || (uses_deducible_template_parms
19322 /* template-name <T> (where template-name refers to a class template)
19323 template-name <i> (where template-name refers to a class template) */
19330 /* type (T)
19331 T()
19332 T(T) */
19335 {
19344 }
19347 }
19349 /* Subroutine of type_unification_real and unify_pack_expansion to
19350 handle unification of a single P/A pair. Parameters are as
19351 for those functions. */
19353 static int
19357 {
19364 /* We can't deduce anything from this, but we might get all the
19365 template args from other function args. */
19368 /* Implicit conversions (Clause 4) will be performed on a function
19369 argument to convert it to the type of the corresponding function
19370 parameter if the parameter type contains no template-parameters that
19371 participate in template argument deduction. */
19374 /* For function parameters with no deducible template parameters,
19375 just return. We'll check non-dependent conversions later. */
19379 {
19381 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
19382 | UNIFY_ALLOW_MORE_CV_QUAL
19396 }
19398 /* We only do these transformations if this is the top-level
19399 parameter_type_list in a call or declaration matching; in other
19400 situations (nested function declarators, template argument lists) we
19401 won't be comparing a type to an expression, and we don't do any type
19402 adjustments. */
19404 {
19406 {
19409 {
19410 /* [temp.deduct.type] A template-argument can be
19411 deduced from a pointer to function or pointer
19412 to member function argument if the set of
19413 overloaded functions does not contain function
19414 templates and at most one of a set of
19415 overloaded functions provides a unique
19416 match. */
19420 /* If a unique match was not found, this is a
19421 non-deduced context, so we still succeed. */
19423 }
19429 }
19431 arg_strict |=
19433 }
19434 else
19439 /* For deduction from an init-list we need the actual list. */
19443 }
19445 /* for_each_template_parm callback that always returns 0. */
19447 static int
19449 {
19451 }
19453 /* for_each_template_parm any_fn callback to handle deduction of a template
19454 type argument from the type of an array bound. */
19456 static int
19458 {
19466 {
19472 }
19474 /* Keep walking. */
19476 }
19478 /* Try to deduce any not-yet-deduced template type arguments from the type of
19479 an array bound. This is handled separately from unify because 14.8.2.5 says
19480 "The type of a type parameter is only deduced from an array bound if it is
19481 not otherwise deduced." */
19483 static void
19485 {
19490 }
19492 /* Most parms like fn_type_unification.
19494 If SUBR is 1, we're being called recursively (to unify the
19495 arguments of a function or method parameter of a function
19496 template).
19498 CHECKS is a pointer to a vector of access checks encountered while
19499 substituting default template arguments. */
19501 static int
19503 tree full_targs,
19504 tree xparms,
19508 unification_kind_t strict,
19512 {
19517 tree parms;
19528 /* Reset the number of non-defaulted template arguments contained
19529 in TARGS. */
19532 again:
19540 {
19545 /* For a function parameter pack that occurs at the end of the
19546 parameter-declaration-list, the type A of each remaining
19547 argument of the call is compared with the type P of the
19548 declarator-id of the function parameter pack. */
19554 /* For a function parameter pack that does not occur at the
19555 end of the parameter-declaration-list, the type of the
19556 parameter pack is a non-deduced context. */
19563 explain_p))
19565 }
19570 {
19571 /* Unify the remaining arguments with the pack expansion type. */
19572 tree argvec;
19575 /* Allocate a TREE_VEC and copy in all of the arguments */
19580 /* Copy the parameter into parmvec. */
19586 /* Advance to the end of the list of parameters. */
19588 }
19590 /* Fail if we've reached the end of the parm list, and more args
19591 are present, and the parm list isn't variadic. */
19594 /* Fail if parms are left and they don't have default values and
19595 they aren't all deduced as empty packs (c++/57397). This is
19596 consistent with sufficient_parms_p. */
19599 {
19603 do
19604 {
19607 count++;
19609 }
19613 type_pack_p);
19614 }
19617 {
19618 tsubst_flags_t complain = (explain_p
19619 ? tf_warning_or_error
19624 {
19628 /* Clear the "incomplete" flags on all argument packs now so that
19629 substituting them into later default arguments works. */
19631 {
19634 }
19642 {
19647 }
19649 /* If this is an undeduced nontype parameter that depends on
19650 a type parameter, try another pass; its type may have been
19651 deduced from a later argument than the one from which
19652 this parameter can be deduced. */
19656 {
19659 }
19661 /* Core issue #226 (C++0x) [temp.deduct]:
19663 If a template argument has not been deduced, its
19664 default template argument, if any, is used.
19666 When we are in C++98 mode, TREE_PURPOSE will either
19667 be NULL_TREE or ERROR_MARK_NODE, so we do not need
19668 to explicitly check cxx_dialect here. */
19670 /* OK, there is a default argument. Wait until after the
19671 conversion check to do substitution. */
19674 /* If the type parameter is a parameter pack, then it will
19675 be deduced to an empty parameter pack. */
19677 {
19678 tree arg;
19681 {
19684 }
19685 else
19692 }
19695 }
19697 /* DR 1391: All parameters have args, now check non-dependent parms for
19698 convertibility. */
19702 {
19708 /* For a function parameter pack that occurs at the end of the
19709 parameter-declaration-list, the type A of each remaining
19710 argument of the call is compared with the type P of the
19711 declarator-id of the function parameter pack. */
19717 /* For a function parameter pack that does not occur at the
19718 end of the parameter-declaration-list, the type of the
19719 parameter pack is a non-deduced context. */
19728 explain_p))
19730 }
19732 /* Now substitute into the default template arguments. */
19734 {
19758 else
19766 {
19768 /* The position of the first default template argument,
19769 is also the number of non-defaulted arguments in TARGS.
19770 Record that. */
19773 }
19774 }
19778 }
19784 }
19786 /* Subroutine of type_unification_real. Args are like the variables
19787 at the call site. ARG is an overloaded function (or template-id);
19788 we try deducing template args from each of the overloads, and if
19789 only one succeeds, we go with that. Modifies TARGS and returns
19790 true on success. */
19792 static bool
19794 tree targs,
19795 tree parm,
19796 tree arg,
19797 unification_kind_t strict,
19800 {
19807 {
19810 }
19811 else
19815 /* Handle `&x' where `x' is some static or non-static member
19816 function name. */
19822 /* Strip baselink information. */
19827 {
19828 /* If we got some explicit template args, we need to plug them into
19829 the affected templates before we try to unify, in case the
19830 explicit args will completely resolve the templates in question. */
19837 {
19850 {
19855 {
19858 }
19859 }
19862 }
19863 /* If no templates (or more than one) are fully resolved by the
19864 explicit arguments, this template-id is a non-deduced context; it
19865 could still be OK if we deduce all template arguments for the
19866 enclosing call through other arguments. */
19869 }
19872 /* If ARG is, for example, "(0, &f)" then its type will be unknown
19873 -- but the deduction does not succeed because the expression is
19874 not just the function on its own. */
19876 else
19878 {
19883 {
19886 }
19887 }
19889 /* [temp.deduct.type] A template-argument can be deduced from a pointer
19890 to function or pointer to member function argument if the set of
19891 overloaded functions does not contain function templates and at most
19892 one of a set of overloaded functions provides a unique match.
19894 So if we found multiple possibilities, we return success but don't
19895 deduce anything. */
19898 {
19902 {
19907 /* Don't forget explicit template arguments in a pack. */
19911 }
19912 }
19917 }
19919 /* Core DR 115: In contexts where deduction is done and fails, or in
19920 contexts where deduction is not done, if a template argument list is
19921 specified and it, along with any default template arguments, identifies
19922 a single function template specialization, then the template-id is an
19923 lvalue for the function template specialization. */
19925 tree
19927 {
19940 {
19943 }
19945 {
19948 }
19950 {
19953 }
19956 {
19960 /* If we got some explicit template args, we need to plug them into
19961 the affected templates before we try to unify, in case the
19962 explicit args will completely resolve the templates in question. */
19970 {
19983 {
19986 {
19989 }
19991 {
19994 }
19995 }
19996 }
19998 {
20006 {
20007 tree base
20010 }
20014 }
20016 /* There were no good options and at least one bad one, so let the
20017 user know what the problem is. */
20019 }
20021 }
20023 /* Subroutine of resolve_overloaded_unification; does deduction for a single
20024 overload. Fills TARGS with any deduced arguments, or error_mark_node if
20025 different overloads deduce different arguments for a given parm.
20026 ADDR_P is true if the expression for which deduction is being
20027 performed was of the form "& fn" rather than simply "fn".
20029 Returns 1 on success. */
20031 static int
20033 tree orig_targs,
20034 tree targs,
20035 tree parm,
20036 tree arg,
20037 unification_kind_t strict,
20041 {
20043 tree tempargs;
20049 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20050 to function or pointer to member function argument if the set of
20051 overloaded functions does not contain function templates and at most
20052 one of a set of overloaded functions provides a unique match.
20054 So if this is a template, just return success. */
20066 /* We don't copy orig_targs for this because if we have already deduced
20067 some template args from previous args, unify would complain when we
20068 try to deduce a template parameter for the same argument, even though
20069 there isn't really a conflict. */
20076 /* First make sure we didn't deduce anything that conflicts with
20077 explicitly specified args. */
20079 {
20086 /* Since we're unifying against ourselves, we will fill in
20087 template args used in the function parm list with our own
20088 template parms. Discard them. */
20091 {
20092 /* Check that the argument at each index of the deduced argument pack
20093 is equivalent to the corresponding explicitly specified argument.
20094 We may have deduced more arguments than were explicitly specified,
20095 and that's OK. */
20097 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
20098 that's wrong if we deduce the same argument pack from multiple
20099 function arguments: it's only incomplete the first time. */
20112 }
20115 }
20118 {
20123 }
20126 }
20128 /* PARM is a template class (perhaps with unbound template
20129 parameters). ARG is a fully instantiated type. If ARG can be
20130 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
20131 TARGS are as for unify. */
20133 static tree
20136 {
20137 tree copy_of_targs;
20147 /* We need to make a new template argument vector for the call to
20148 unify. If we used TARGS, we'd clutter it up with the result of
20149 the attempted unification, even if this class didn't work out.
20150 We also don't want to commit ourselves to all the unifications
20151 we've already done, since unification is supposed to be done on
20152 an argument-by-argument basis. In other words, consider the
20153 following pathological case:
20155 template <int I, int J, int K>
20156 struct S {};
20158 template <int I, int J>
20159 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
20161 template <int I, int J, int K>
20162 void f(S<I, J, K>, S<I, I, I>);
20164 void g() {
20165 S<0, 0, 0> s0;
20166 S<0, 1, 2> s2;
20168 f(s0, s2);
20169 }
20171 Now, by the time we consider the unification involving `s2', we
20172 already know that we must have `f<0, 0, 0>'. But, even though
20173 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
20174 because there are two ways to unify base classes of S<0, 1, 2>
20175 with S<I, I, I>. If we kept the already deduced knowledge, we
20176 would reject the possibility I=1. */
20180 {
20184 }
20186 /* If unification failed, we're done. */
20192 }
20194 /* Given a template type PARM and a class type ARG, find the unique
20195 base type in ARG that is an instance of PARM. We do not examine
20196 ARG itself; only its base-classes. If there is not exactly one
20197 appropriate base class, return NULL_TREE. PARM may be the type of
20198 a partial specialization, as well as a plain template type. Used
20199 by unify. */
20201 static enum template_base_result
20204 {
20206 tree binfo;
20212 {
20213 /* The type could not be completed. */
20216 }
20218 /* Walk in inheritance graph order. The search order is not
20219 important, and this avoids multiple walks of virtual bases. */
20221 {
20226 {
20227 /* If there is more than one satisfactory baseclass, then:
20229 [temp.deduct.call]
20231 If they yield more than one possible deduced A, the type
20232 deduction fails.
20234 applies. */
20236 {
20239 }
20242 }
20243 }
20247 }
20249 /* Returns the level of DECL, which declares a template parameter. */
20251 static int
20253 {
20255 {
20265 }
20267 }
20269 /* Decide whether ARG can be unified with PARM, considering only the
20270 cv-qualifiers of each type, given STRICT as documented for unify.
20271 Returns nonzero iff the unification is OK on that basis. */
20273 static int
20275 {
20281 {
20282 /* Although a CVR qualifier is ignored when being applied to a
20283 substituted template parameter ([8.3.2]/1 for example), that
20284 does not allow us to unify "const T" with "int&" because both
20285 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
20286 It is ok when we're allowing additional CV qualifiers
20287 at the outer level [14.8.2.1]/3,1st bullet. */
20297 }
20308 }
20310 /* Determines the LEVEL and INDEX for the template parameter PARM. */
20311 void
20313 {
20317 {
20320 }
20321 else
20322 {
20325 }
20326 }
20328 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
20329 do { \
20330 if (unify (TP, TA, P, A, S, EP)) \
20331 return 1; \
20332 } while (0)
20334 /* Unifies the remaining arguments in PACKED_ARGS with the pack
20335 expansion at the end of PACKED_PARMS. Returns 0 if the type
20336 deduction succeeds, 1 otherwise. STRICT is the same as in
20337 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
20338 function call argument list. We'll need to adjust the arguments to make them
20339 types. SUBR tells us if this is from a recursive call to
20340 type_unification_real, or for comparing two template argument
20341 lists. */
20343 static int
20347 {
20348 tree parm
20354 /* Add in any args remembered from an earlier partial instantiation. */
20361 /* Determine the parameter packs we will be deducing from the
20362 pattern, and record their current deductions. */
20365 {
20369 /* Determine the index and level of this parameter pack. */
20372 /* Keep track of the parameter packs and their corresponding
20373 argument packs. */
20376 }
20378 /* Loop through all of the arguments that have not yet been
20379 unified and unify each with the pattern. */
20381 {
20382 tree parm;
20386 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
20387 or the element of its argument pack at the current index if
20388 this argument was explicitly specified. */
20390 {
20399 {
20402 }
20404 }
20406 /* If we had explicit template arguments, substitute them into the
20407 pattern before deduction. */
20409 {
20410 /* Some arguments might still be unspecified or dependent. */
20418 NULL_TREE);
20423 }
20424 else
20427 /* Unify the pattern with the current argument. */
20429 explain_p))
20432 /* For each parameter pack, collect the deduced value. */
20434 {
20440 }
20441 }
20443 /* Verify that the results of unification with the parameter packs
20444 produce results consistent with what we've seen before, and make
20445 the deduced argument packs available. */
20447 {
20454 /* By default keep the original deduced argument pack.
20455 If necessary, more specific code is going to update the
20456 resulting deduced argument later down in this function. */
20460 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
20461 actually deduce anything. */
20469 {
20470 /* If we had fewer function args than explicit template args,
20471 just use the explicits. */
20476 }
20479 {
20480 tree result;
20481 /* Build the deduced *_ARGUMENT_PACK. */
20483 {
20486 }
20487 else
20492 /* Note the deduced argument packs for this parameter
20493 pack. */
20495 }
20499 {
20500 /* We only had the explicitly-provided arguments before, but
20501 now we have a complete set of arguments. */
20507 }
20508 else
20509 {
20515 /* Inconsistent unification of this parameter pack. */
20517 bad_old_arg,
20518 bad_new_arg);
20519 }
20520 }
20523 }
20525 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
20526 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
20527 parameters and return value are as for unify. */
20529 static int
20533 {
20534 tree parm_max;
20535 tree arg_max;
20539 /* Our representation of array types uses "N - 1" as the
20540 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
20541 not an integer constant. We cannot unify arbitrarily
20542 complex expressions, so we eliminate the MINUS_EXPRs
20543 here. */
20547 {
20550 }
20554 {
20555 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
20556 trying to unify the type of a variable with the type
20557 of a template parameter. For example:
20559 template <unsigned int N>
20560 void f (char (&) [N]);
20561 int g();
20562 void h(int i) {
20563 char a[g(i)];
20564 f(a);
20565 }
20567 Here, the type of the ARG will be "int [g(i)]", and
20568 may be a SAVE_EXPR, etc. */
20572 }
20574 /* If only one of the bounds used a MINUS_EXPR, compensate
20575 by adding one to the other bound. */
20578 integer_type_node,
20579 parm_max,
20580 integer_one_node);
20583 integer_type_node,
20584 arg_max,
20585 integer_one_node);
20589 }
20591 /* Returns whether T, a P or A in unify, is a type, template or expression. */
20595 static pa_kind_t
20597 {
20606 else
20608 }
20610 /* Deduce the value of template parameters. TPARMS is the (innermost)
20611 set of template parameters to a template. TARGS is the bindings
20612 for those template parameters, as determined thus far; TARGS may
20613 include template arguments for outer levels of template parameters
20614 as well. PARM is a parameter to a template function, or a
20615 subcomponent of that parameter; ARG is the corresponding argument.
20616 This function attempts to match PARM with ARG in a manner
20617 consistent with the existing assignments in TARGS. If more values
20618 are deduced, then TARGS is updated.
20620 Returns 0 if the type deduction succeeds, 1 otherwise. The
20621 parameter STRICT is a bitwise or of the following flags:
20623 UNIFY_ALLOW_NONE:
20624 Require an exact match between PARM and ARG.
20625 UNIFY_ALLOW_MORE_CV_QUAL:
20626 Allow the deduced ARG to be more cv-qualified (by qualification
20627 conversion) than ARG.
20628 UNIFY_ALLOW_LESS_CV_QUAL:
20629 Allow the deduced ARG to be less cv-qualified than ARG.
20630 UNIFY_ALLOW_DERIVED:
20631 Allow the deduced ARG to be a template base class of ARG,
20632 or a pointer to a template base class of the type pointed to by
20633 ARG.
20634 UNIFY_ALLOW_INTEGER:
20635 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
20636 case for more information.
20637 UNIFY_ALLOW_OUTER_LEVEL:
20638 This is the outermost level of a deduction. Used to determine validity
20639 of qualification conversions. A valid qualification conversion must
20640 have const qualified pointers leading up to the inner type which
20641 requires additional CV quals, except at the outer level, where const
20642 is not required [conv.qual]. It would be normal to set this flag in
20643 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
20644 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
20645 This is the outermost level of a deduction, and PARM can be more CV
20646 qualified at this point.
20647 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
20648 This is the outermost level of a deduction, and PARM can be less CV
20649 qualified at this point. */
20651 static int
20654 {
20656 tree targ;
20657 tree tparm;
20659 tsubst_flags_t complain = (explain_p
20660 ? tf_warning_or_error
20663 /* I don't think this will do the right thing with respect to types.
20664 But the only case I've seen it in so far has been array bounds, where
20665 signedness is the only information lost, and I think that will be
20666 okay. */
20674 /* We can't deduce anything from this, but we might get all the
20675 template args from other function args. */
20681 /* If PARM uses template parameters, then we can't bail out here,
20682 even if ARG == PARM, since we won't record unifications for the
20683 template parameters. We might need them if we're trying to
20684 figure out which of two things is more specialized. */
20688 /* Handle init lists early, so the rest of the function can assume
20689 we're dealing with a type. */
20691 {
20696 /* Replace T with std::initializer_list<T> for deduction. */
20703 /* We can only deduce from an initializer list argument if the
20704 parameter is std::initializer_list or an array; otherwise this
20705 is a non-deduced context. */
20710 else
20711 {
20713 /* Deduction is defined in terms of a single type, so just punt
20714 on the (bizarre) std::initializer_list<T...>. */
20717 }
20720 {
20727 {
20731 /* It should only be possible to get here for a call. */
20733 elt_strict |= maybe_adjust_types_for_deduction
20736 }
20739 explain_p);
20740 }
20744 {
20745 /* Also deduce from the length of the initializer list. */
20752 }
20754 /* If the std::initializer_list<T> deduction worked, replace the
20755 deduced A with std::initializer_list<A>. */
20757 {
20762 }
20764 }
20766 /* If parm and arg aren't the same kind of thing (template, type, or
20767 expression), fail early. */
20771 /* Immediately reject some pairs that won't unify because of
20772 cv-qualification mismatches. */
20775 /* It is the elements of the array which hold the cv quals of an array
20776 type, and the elements might be template type parms. We'll check
20777 when we recurse. */
20779 /* We check the cv-qualifiers when unifying with template type
20780 parameters below. We want to allow ARG `const T' to unify with
20781 PARM `T' for example, when computing which of two templates
20782 is more specialized, for example. */
20796 {
20800 /* In a type which contains a nested-name-specifier, template
20801 argument values cannot be deduced for template parameters used
20802 within the nested-name-specifier. */
20814 /* The PARM is not one we're trying to unify. Just check
20815 to see if it matches ARG. */
20816 {
20821 else
20823 }
20830 /* Check for mixed types and values. */
20838 {
20841 {
20842 /* First try to match ARG directly. */
20844 explain_p);
20846 {
20847 /* Otherwise, look for a suitable base of ARG, as below. */
20854 }
20855 }
20856 /* ARG must be constructed from a template class or a template
20857 template parameter. */
20862 /* Deduce arguments T, i from TT<T> or TT<i>. */
20868 /* Fall through to deduce template name. */
20869 }
20873 {
20874 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
20876 /* Simple cases: Value already set, does match or doesn't. */
20881 }
20882 else
20883 {
20884 /* If PARM is `const T' and ARG is only `int', we don't have
20885 a match unless we are allowing additional qualification.
20886 If ARG is `const int' and PARM is just `T' that's OK;
20887 that binds `const int' to `T'. */
20892 /* Consider the case where ARG is `const volatile int' and
20893 PARM is `const T'. Then, T should be `volatile int'. */
20894 arg = cp_build_qualified_type_real
20899 /* Simple cases: Value already set, does match or doesn't. */
20905 /* Make sure that ARG is not a variable-sized array. (Note
20906 that were talking about variable-sized arrays (like
20907 `int[n]'), rather than arrays of unknown size (like
20908 `int[]').) We'll get very confused by such a type since
20909 the bound of the array is not constant, and therefore
20910 not mangleable. Besides, such types are not allowed in
20911 ISO C++, so we can do as we please here. We do allow
20912 them for 'auto' deduction, since that isn't ABI-exposed. */
20916 /* Strip typedefs as in convert_template_argument. */
20918 }
20920 /* If ARG is a parameter pack or an expansion, we cannot unify
20921 against it unless PARM is also a parameter pack. */
20926 /* If the argument deduction results is a METHOD_TYPE,
20927 then there is a problem.
20928 METHOD_TYPE doesn't map to any real C++ type the result of
20929 the deduction can not be of that type. */
20943 {
20944 /* The PARM is not one we're trying to unify. Just check
20945 to see if it matches ARG. */
20951 }
20957 {
20961 /* We're deducing from an array bound, the type doesn't matter. */
20967 }
20969 /* [temp.deduct.type] If, in the declaration of a function template
20970 with a non-type template-parameter, the non-type
20971 template-parameter is used in an expression in the function
20972 parameter-list and, if the corresponding template-argument is
20973 deduced, the template-argument type shall match the type of the
20974 template-parameter exactly, except that a template-argument
20975 deduced from an array bound may be of any integral type.
20976 The non-type parameter might use already deduced type parameters. */
20981 {
20985 }
20988 /* Template-parameter dependent expression. Just accept it for now.
20989 It will later be processed in convert_template_argument. */
20990 ;
20996 /* Convert the ARG to the type of PARM; the deduced non-type
20997 template argument must exactly match the types of the
20998 corresponding parameter. */
21001 {
21002 /* We haven't deduced the type of this parameter yet. */
21004 /* We deduce from array bounds in try_array_deduction. */
21006 {
21007 /* Deduce it from the non-type argument. */
21012 }
21013 else
21014 /* Try again later. */
21016 }
21017 else
21020 /* If ARG is a parameter pack or an expansion, we cannot unify
21021 against it unless PARM is also a parameter pack. */
21026 {
21029 }
21034 {
21035 /* A pointer-to-member constant can be unified only with
21036 another constant. */
21040 /* Just unify the class member. It would be useless (and possibly
21041 wrong, depending on the strict flags) to unify also
21042 PTRMEM_CST_CLASS, because we want to be sure that both parm and
21043 arg refer to the same variable, even if through different
21044 classes. For instance:
21046 struct A { int x; };
21047 struct B : A { };
21049 Unification of &A::x and &B::x must succeed. */
21052 }
21055 {
21059 /* [temp.deduct.call]
21061 A can be another pointer or pointer to member type that can
21062 be converted to the deduced A via a qualification
21063 conversion (_conv.qual_).
21065 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
21066 This will allow for additional cv-qualification of the
21067 pointed-to types if appropriate. */
21070 /* The derived-to-base conversion only persists through one
21071 level of pointers. */
21076 }
21108 /* We have already checked cv-qualification at the top of the
21109 function. */
21113 /* As far as unification is concerned, this wins. Later checks
21114 will invalidate it if necessary. */
21117 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
21118 /* Type INTEGER_CST can come from ordinary constant template args. */
21130 {
21140 /* Check for pack expansions in the parameters. */
21142 {
21144 {
21146 /* We can unify against something with a trailing
21147 parameter pack. */
21149 else
21150 /* [temp.deduct.type]/9: If the template argument list of
21151 P contains a pack expansion that is not the last
21152 template argument, the entire template argument list
21153 is a non-deduced context. */
21155 }
21156 }
21158 /* If we don't have enough arguments to satisfy the parameters
21159 (not counting the pack expression at the end), or we have
21160 too many arguments for a parameter list that doesn't end in
21161 a pack expression, we can't unify. */
21167 /* Unify all of the parameters that precede the (optional)
21168 pack expression. */
21170 {
21175 }
21178 DEDUCE_EXACT,
21181 }
21189 {
21197 }
21202 {
21206 {
21207 /* First, we try to unify the PARM and ARG directly. */
21212 {
21213 /* Fallback to the special case allowed in
21214 [temp.deduct.call]:
21216 If P is a class, and P has the form
21217 template-id, then A can be a derived class of
21218 the deduced A. Likewise, if P is a pointer to
21219 a class of the form template-id, A can be a
21220 pointer to a derived class pointed to by the
21221 deduced A. */
21227 {
21228 /* Don't give the derived diagnostic if we're
21229 already dealing with the same template. */
21230 bool same_template
21236 }
21237 }
21238 }
21242 /* Perhaps PARM is something like S<U> and ARG is S<int>.
21243 Then, we should unify `int' and `U'. */
21245 else
21246 /* There's no chance of unification succeeding. */
21251 }
21258 {
21261 tree a;
21267 /* CV qualifications for methods can never be deduced, they must
21268 match exactly. We need to check them explicitly here,
21269 because type_unification_real treats them as any other
21270 cv-qualified parameter. */
21272 && (!check_cv_quals_for_unify
21300 {
21312 }
21315 }
21318 /* Unify a pointer to member with a pointer to member function, which
21319 deduces the type of the member as a function type. */
21321 {
21322 /* Check top-level cv qualifiers */
21330 /* Determine the type of the function we are unifying against. */
21334 }
21353 /* Matched cases are handled by the ARG == PARM test above. */
21357 /* We might get a variable as a non-type template argument in parm if the
21358 corresponding parameter is type-dependent. Make any necessary
21359 adjustments based on whether arg is a reference. */
21363 {
21368 }
21369 /* Now use the normal expression code to check whether they match. */
21380 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
21381 or UNDERLYING_TYPE nodes. */
21385 /* Unification fails if we hit an error node. */
21390 {
21400 }
21401 /* FALLTHRU */
21404 /* An unresolved overload is a nondeduced context. */
21408 expr:
21409 /* We must be looking at an expression. This can happen with
21410 something like:
21412 template <int I>
21413 void foo(S<I>, S<I + 2>);
21415 This is a "nondeduced context":
21417 [deduct.type]
21419 The nondeduced contexts are:
21421 --A type that is a template-id in which one or more of
21422 the template-arguments is an expression that references
21423 a template-parameter.
21425 In these cases, we assume deduction succeeded, but don't
21426 actually infer any unifications. */
21431 else
21433 }
21434 }
21435 #undef RECUR_AND_CHECK_FAILURE
21436 \f
21437 /* Note that DECL can be defined in this translation unit, if
21438 required. */
21440 static void
21442 {
21443 tree clone;
21447 }
21449 /* Called if RESULT is explicitly instantiated, or is a member of an
21450 explicitly instantiated class. */
21452 void
21454 {
21457 /* If this entity has already been written out, it's too late to
21458 make any modifications. */
21462 /* For anonymous namespace we don't need to do anything. */
21464 {
21467 }
21470 /* The TREE_PUBLIC flag for function declarations will have been
21471 set correctly by tsubst. */
21474 /* This might have been set by an earlier implicit instantiation. */
21479 else
21480 {
21483 /* Always make artificials weak. */
21486 /* For WIN32 we also want to put explicit instantiations in
21487 linkonce sections. */
21490 }
21492 /* If EXTERN_P, then this function will not be emitted -- unless
21493 followed by an explicit instantiation, at which point its linkage
21494 will be adjusted. If !EXTERN_P, then this function will be
21495 emitted here. In neither circumstance do we want
21496 import_export_decl to adjust the linkage. */
21498 }
21500 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
21501 important template arguments. If any are missing, we check whether
21502 they're important by using error_mark_node for substituting into any
21503 args that were used for partial ordering (the ones between ARGS and END)
21504 and seeing if it bubbles up. */
21506 static bool
21508 {
21513 {
21516 }
21518 {
21522 }
21524 }
21526 /* Given two function templates PAT1 and PAT2, return:
21528 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
21529 -1 if PAT2 is more specialized than PAT1.
21530 0 if neither is more specialized.
21532 LEN indicates the number of parameters we should consider
21533 (defaulted parameters should not be considered).
21535 The 1998 std underspecified function template partial ordering, and
21536 DR214 addresses the issue. We take pairs of arguments, one from
21537 each of the templates, and deduce them against each other. One of
21538 the templates will be more specialized if all the *other*
21539 template's arguments deduce against its arguments and at least one
21540 of its arguments *does* *not* deduce against the other template's
21541 corresponding argument. Deduction is done as for class templates.
21542 The arguments used in deduction have reference and top level cv
21543 qualifiers removed. Iff both arguments were originally reference
21544 types *and* deduction succeeds in both directions, an lvalue reference
21545 wins against an rvalue reference and otherwise the template
21546 with the more cv-qualified argument wins for that pairing (if
21547 neither is more cv-qualified, they both are equal). Unlike regular
21548 deduction, after all the arguments have been deduced in this way,
21549 we do *not* verify the deduced template argument values can be
21550 substituted into non-deduced contexts.
21552 The logic can be a bit confusing here, because we look at deduce1 and
21553 targs1 to see if pat2 is at least as specialized, and vice versa; if we
21554 can find template arguments for pat1 to make arg1 look like arg2, that
21555 means that arg2 is at least as specialized as arg1. */
21557 int
21559 {
21572 /* Remove the this parameter from non-static member functions. If
21573 one is a non-static member function and the other is not a static
21574 member function, remove the first parameter from that function
21575 also. This situation occurs for operator functions where we
21576 locate both a member function (with this pointer) and non-member
21577 operator (with explicit first operand). */
21579 {
21584 }
21586 {
21589 {
21590 len--;
21592 }
21593 }
21595 /* If only one is a conversion operator, they are unordered. */
21599 /* Consider the return type for a conversion function */
21601 {
21604 len++;
21605 }
21607 processing_template_decl++;
21613 /* Stop when an ellipsis is seen. */
21615 {
21626 {
21627 /* When both arguments are pack expansions, we need only
21628 unify the patterns themselves. */
21632 /* This is the last comparison we need to do. */
21634 }
21636 /* DR 1847: If a particular P contains no template-parameters that
21637 participate in template argument deduction, that P is not used to
21638 determine the ordering. */
21644 {
21648 }
21651 {
21655 }
21661 {
21667 /* Setup the parameter vector, which contains only ARG1. */
21670 /* Setup the argument vector, which contains the remaining
21671 arguments. */
21680 /* We cannot deduce in the other direction, because ARG1 is
21681 a pack expansion but ARG2 is not. */
21683 }
21685 {
21691 /* Setup the parameter vector, which contains only ARG1. */
21694 /* Setup the argument vector, which contains the remaining
21695 arguments. */
21704 /* We cannot deduce in the other direction, because ARG2 is
21705 a pack expansion but ARG1 is not.*/
21707 }
21709 else
21710 {
21711 /* The normal case, where neither argument is a pack
21712 expansion. */
21719 }
21721 /* If we couldn't deduce arguments for tparms1 to make arg1 match
21722 arg2, then arg2 is not as specialized as arg1. */
21728 /* "If, for a given type, deduction succeeds in both directions
21729 (i.e., the types are identical after the transformations above)
21730 and both P and A were reference types (before being replaced with
21731 the type referred to above):
21732 - if the type from the argument template was an lvalue reference and
21733 the type from the parameter template was not, the argument type is
21734 considered to be more specialized than the other; otherwise,
21735 - if the type from the argument template is more cv-qualified
21736 than the type from the parameter template (as described above),
21737 the argument type is considered to be more specialized than the other;
21738 otherwise,
21739 - neither type is more specialized than the other." */
21742 {
21744 {
21747 else
21749 }
21751 {
21756 }
21757 }
21760 /* We've failed to deduce something in either direction.
21761 These must be unordered. */
21764 next:
21768 /* We have already processed all of the arguments in our
21769 handing of the pack expansion type. */
21774 }
21776 /* "In most cases, all template parameters must have values in order for
21777 deduction to succeed, but for partial ordering purposes a template
21778 parameter may remain without a value provided it is not used in the
21779 types being used for partial ordering."
21781 Thus, if we are missing any of the targs1 we need to substitute into
21782 origs1, then pat2 is not as specialized as pat1. This can happen when
21783 there is a nondeduced context. */
21789 processing_template_decl--;
21791 /* If both deductions succeed, the partial ordering selects the more
21792 constrained template. */
21794 {
21799 }
21801 /* All things being equal, if the next argument is a pack expansion
21802 for one function but not for the other, prefer the
21803 non-variadic function. FIXME this is bogus; see c++/41958. */
21807 {
21810 }
21816 else
21818 }
21820 /* Determine which of two partial specializations of TMPL is more
21821 specialized.
21823 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
21824 to the first partial specialization. The TREE_PURPOSE is the
21825 innermost set of template parameters for the partial
21826 specialization. PAT2 is similar, but for the second template.
21828 Return 1 if the first partial specialization is more specialized;
21829 -1 if the second is more specialized; 0 if neither is more
21830 specialized.
21832 See [temp.class.order] for information about determining which of
21833 two templates is more specialized. */
21835 static int
21837 {
21838 tree targs;
21847 /* Just like what happens for functions, if we are ordering between
21848 different template specializations, we may encounter dependent
21849 types in the arguments, and we need our dependency check functions
21850 to behave correctly. */
21854 {
21857 }
21861 {
21864 }
21867 /* If both deductions succeed, the partial ordering selects the more
21868 constrained template. */
21872 /* In the case of a tie where at least one of the templates
21873 has a parameter pack at the end, the template with the most
21874 non-packed parameters wins. */
21876 && any_deductions
21879 {
21885 /* We don't count the pack expansion at the end. */
21895 }
21898 }
21900 /* Return the template arguments that will produce the function signature
21901 DECL from the function template FN, with the explicit template
21902 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
21903 also match. Return NULL_TREE if no satisfactory arguments could be
21904 found. */
21906 static tree
21908 {
21912 tree decl_arg_types;
21915 tree arg;
21919 /* Never do unification on the 'this' parameter. */
21940 }
21942 /* Return the innermost template arguments that, when applied to a partial
21943 specialization SPEC_TMPL of TMPL, yield the ARGS.
21945 For example, suppose we have:
21947 template <class T, class U> struct S {};
21948 template <class T> struct S<T*, int> {};
21950 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
21951 partial specialization and the ARGS will be {double*, int}. The resulting
21952 vector will be {double}, indicating that `T' is bound to `double'. */
21954 static tree
21956 {
21958 tree spec_args
21961 tree deduced_args;
21962 tree innermost_deduced_args;
21966 {
21970 innermost_deduced_args);
21971 }
21972 else
21976 again:
21985 {
21987 {
21993 }
21995 }
21999 {
22002 }
22004 /* Verify that nondeduced template arguments agree with the type
22005 obtained from argument deduction.
22007 For example:
22009 struct A { typedef int X; };
22010 template <class T, class U> struct C {};
22011 template <class T> struct C<T, typename T::X> {};
22013 Then with the instantiation `C<A, int>', we can deduce that
22014 `T' is `A' but unify () does not check whether `typename T::X'
22015 is `int'. */
22026 /* We only need to check the innermost arguments; the other
22027 arguments will always agree. */
22032 /* Now that we have bindings for all of the template arguments,
22033 ensure that the arguments deduced for the template template
22034 parameters have compatible template parameter lists. See the use
22035 of template_template_parm_bindings_ok_p in fn_type_unification
22036 for more information. */
22041 }
22043 // Compare two function templates T1 and T2 by deducing bindings
22044 // from one against the other. If both deductions succeed, compare
22045 // constraints to see which is more constrained.
22046 static int
22048 {
22053 {
22056 }
22059 {
22062 }
22064 // If both deductions succeed, then one may be more constrained.
22069 }
22071 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
22072 Return the TREE_LIST node with the most specialized template, if
22073 any. If there is no most specialized template, the error_mark_node
22074 is returned.
22076 Note that this function does not look at, or modify, the
22077 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
22078 returned is one of the elements of INSTANTIATIONS, callers may
22079 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
22080 and retrieve it from the value returned. */
22082 tree
22084 {
22091 {
22097 {
22098 /* Equally specialized, move to next function. If there
22099 is no next function, nothing's most specialized. */
22104 }
22105 }
22108 /* Now verify that champ is better than everything earlier in the
22109 instantiation list. */
22112 {
22115 }
22116 }
22118 processing_template_decl--;
22124 }
22126 /* If DECL is a specialization of some template, return the most
22127 general such template. Otherwise, returns NULL_TREE.
22129 For example, given:
22131 template <class T> struct S { template <class U> void f(U); };
22133 if TMPL is `template <class U> void S<int>::f(U)' this will return
22134 the full template. This function will not trace past partial
22135 specializations, however. For example, given in addition:
22137 template <class T> struct S<T*> { template <class U> void f(U); };
22139 if TMPL is `template <class U> void S<int*>::f(U)' this will return
22140 `template <class T> template <class U> S<T*>::f(U)'. */
22142 tree
22144 {
22146 {
22149 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
22150 template friend, or a FIELD_DECL for a capture pack. */
22153 }
22155 /* Look for more and more general templates. */
22157 {
22158 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
22159 (See cp-tree.h for details.) */
22168 /* Stop if we run into an explicitly specialized class template. */
22175 }
22178 }
22180 /* Return the most specialized of the template partial specializations
22181 which can produce TARGET, a specialization of some class or variable
22182 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
22183 a TEMPLATE_DECL node corresponding to the partial specialization, while
22184 the TREE_PURPOSE is the set of template arguments that must be
22185 substituted into the template pattern in order to generate TARGET.
22187 If the choice of partial specialization is ambiguous, a diagnostic
22188 is issued, and the error_mark_node is returned. If there are no
22189 partial specializations matching TARGET, then NULL_TREE is
22190 returned, indicating that the primary template should be used. */
22192 static tree
22194 {
22196 tree t;
22197 tree champ;
22204 {
22208 }
22210 {
22213 }
22215 {
22219 }
22220 else
22225 /* For determining which partial specialization to use, only the
22226 innermost args are interesting. */
22228 {
22231 }
22234 {
22235 tree spec_args;
22239 {
22240 /* Substitute in the template args from the enclosing class. */
22244 }
22251 {
22255 /* Keep the candidate only if the constraints are satisfied,
22256 or if we're not compiling with concepts. */
22259 {
22262 }
22263 }
22264 }
22274 {
22277 ;
22278 else
22279 {
22281 {
22284 {
22287 }
22288 }
22290 }
22291 }
22295 {
22298 {
22301 }
22302 }
22305 {
22312 else
22316 {
22321 }
22324 }
22327 }
22329 /* Explicitly instantiate DECL. */
22331 void
22333 {
22338 /* An error occurred, for which grokdeclarator has already issued
22339 an appropriate message. */
22342 {
22345 }
22351 {
22352 /* There is an asymmetry here in the way VAR_DECLs and
22353 FUNCTION_DECLs are handled by grokdeclarator. In the case of
22354 the latter, the DECL we get back will be marked as a
22355 template instantiation, and the appropriate
22356 DECL_TEMPLATE_INFO will be set up. This does not happen for
22357 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
22358 should handle VAR_DECLs as it currently handles
22359 FUNCTION_DECLs. */
22361 {
22364 }
22367 {
22370 }
22372 {
22377 }
22378 }
22380 {
22383 }
22384 else
22387 /* Check for various error cases. Note that if the explicit
22388 instantiation is valid the RESULT will currently be marked as an
22389 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
22390 until we get here. */
22393 {
22394 /* DR 259 [temp.spec].
22396 Both an explicit instantiation and a declaration of an explicit
22397 specialization shall not appear in a program unless the explicit
22398 instantiation follows a declaration of the explicit specialization.
22400 For a given set of template parameters, if an explicit
22401 instantiation of a template appears after a declaration of an
22402 explicit specialization for that template, the explicit
22403 instantiation has no effect. */
22405 }
22407 {
22408 /* [temp.spec]
22410 No program shall explicitly instantiate any template more
22411 than once.
22413 We check DECL_NOT_REALLY_EXTERN so as not to complain when
22414 the first instantiation was `extern' and the second is not,
22415 and EXTERN_P for the opposite case. */
22418 /* If an "extern" explicit instantiation follows an ordinary
22419 explicit instantiation, the template is instantiated. */
22422 }
22424 {
22427 }
22429 {
22432 }
22435 ;
22437 {
22440 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
22443 }
22444 else
22452 }
22454 static void
22456 {
22462 {
22465 }
22466 }
22468 /* Called from do_type_instantiation through binding_table_foreach to
22469 do recursive instantiation for the type bound in ENTRY. */
22470 static void
22472 {
22478 }
22480 /* Perform an explicit instantiation of template class T. STORAGE, if
22481 non-null, is the RID for extern, inline or static. COMPLAIN is
22482 nonzero if this is called from the parser, zero if called recursively,
22483 since the standard is unclear (as detailed below). */
22485 void
22487 {
22497 {
22498 tree tmpl =
22502 else
22505 }
22510 {
22513 t);
22515 }
22518 {
22520 {
22522 {
22525 "ISO C++ 1998 forbids the use of %<extern%> on "
22527 }
22528 else
22530 "ISO C++ forbids the use of %qE"
22532 }
22540 else
22541 {
22543 storage);
22545 }
22546 }
22549 {
22550 /* DR 259 [temp.spec].
22552 Both an explicit instantiation and a declaration of an explicit
22553 specialization shall not appear in a program unless the explicit
22554 instantiation follows a declaration of the explicit specialization.
22556 For a given set of template parameters, if an explicit
22557 instantiation of a template appears after a declaration of an
22558 explicit specialization for that template, the explicit
22559 instantiation has no effect. */
22561 }
22563 {
22564 /* [temp.spec]
22566 No program shall explicitly instantiate any template more
22567 than once.
22569 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
22570 instantiation was `extern'. If EXTERN_P then the second is.
22571 These cases are OK. */
22578 /* If we've already instantiated the template, just return now. */
22581 }
22589 /* In contrast to implicit instantiation, where only the
22590 declarations, and not the definitions, of members are
22591 instantiated, we have here:
22593 [temp.explicit]
22595 The explicit instantiation of a class template specialization
22596 implies the instantiation of all of its members not
22597 previously explicitly specialized in the translation unit
22598 containing the explicit instantiation.
22600 Of course, we can't instantiate member template classes, since we
22601 don't have any arguments for them. Note that the standard is
22602 unclear on whether the instantiation of the members are
22603 *explicit* instantiations or not. However, the most natural
22604 interpretation is that it should be an explicit
22605 instantiation. */
22609 && !static_p
22612 {
22617 }
22622 }
22624 /* Given a function DECL, which is a specialization of TMPL, modify
22625 DECL to be a re-instantiation of TMPL with the same template
22626 arguments. TMPL should be the template into which tsubst'ing
22627 should occur for DECL, not the most general template.
22629 One reason for doing this is a scenario like this:
22631 template <class T>
22632 void f(const T&, int i);
22634 void g() { f(3, 7); }
22636 template <class T>
22637 void f(const T& t, const int i) { }
22639 Note that when the template is first instantiated, with
22640 instantiate_template, the resulting DECL will have no name for the
22641 first parameter, and the wrong type for the second. So, when we go
22642 to instantiate the DECL, we regenerate it. */
22644 static void
22646 {
22647 /* The arguments used to instantiate DECL, from the most general
22648 template. */
22649 tree code_pattern;
22653 /* Make sure that we can see identifiers, and compute access
22654 correctly. */
22658 {
22659 tree decl_parm;
22660 tree pattern_parm;
22661 tree specs;
22675 specs);
22677 /* Merge parameter declarations. */
22680 pattern_parm
22684 {
22685 tree parm_type;
22686 tree attributes;
22691 NULL_TREE);
22697 {
22700 }
22703 }
22704 /* Merge any parameters that match with the function parameter
22705 pack. */
22707 {
22709 tree expanded_types;
22710 /* Expand the TYPE_PACK_EXPANSION that provides the types for
22711 the parameters in this function parameter pack. */
22716 {
22717 tree parm_type;
22718 tree attributes;
22721 /* Rename the parameter to include the index. */
22730 {
22733 }
22735 }
22736 }
22737 /* Merge additional specifiers from the CODE_PATTERN. */
22741 }
22743 {
22753 }
22754 else
22758 }
22760 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
22761 substituted to get DECL. */
22763 tree
22765 {
22768 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
22769 for the instantiation. This is not always the most general
22770 template. Consider, for example:
22772 template <class T>
22773 struct S { template <class U> void f();
22774 template <> void f<int>(); };
22776 and an instantiation of S<double>::f<int>. We want TD to be the
22777 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
22779 more general template. */
22781 /* We must also deal with friend templates. Given:
22783 template <class T> struct S {
22784 template <class U> friend void f() {};
22785 };
22787 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
22788 so far as the language is concerned, but that's still
22789 where we get the pattern for the instantiation from. On
22790 other hand, if the definition comes outside the class, say:
22792 template <class T> struct S {
22793 template <class U> friend void f();
22794 };
22795 template <class U> friend void f() {}
22797 we don't need to look any further. That's what the check for
22798 DECL_INITIAL is for. */
22802 {
22803 /* The present template, TD, should not be a definition. If it
22804 were a definition, we should be using it! Note that we
22805 cannot restructure the loop to just keep going until we find
22806 a template with a definition, since that might go too far if
22807 a specialization was declared, but not defined. */
22809 /* Fetch the more general template. */
22811 }
22814 }
22816 /* Returns true if we need to instantiate this template instance even if we
22817 know we aren't going to emit it. */
22819 bool
22821 {
22822 /* We always instantiate inline functions so that we can inline them. An
22823 explicit instantiation declaration prohibits implicit instantiation of
22824 non-inline functions. With high levels of optimization, we would
22825 normally inline non-inline functions -- but we're not allowed to do
22826 that for "extern template" functions. Therefore, we check
22827 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
22831 /* And we need to instantiate static data members so that
22832 their initializers are available in integral constant
22833 expressions. */
22836 }
22838 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
22839 instantiate it now, modifying TREE_TYPE (fn). Returns false on
22840 error, true otherwise. */
22842 bool
22844 {
22847 /* Don't instantiate a noexcept-specification from template context. */
22862 {
22868 {
22869 /* If hash_set::add returns true, the element was already there. */
22874 fn);
22876 }
22878 {
22893 }
22894 else
22904 }
22907 {
22910 else
22912 }
22915 }
22917 /* We're starting to process the function INST, an instantiation of PATTERN;
22918 add their parameters to local_specializations. */
22920 static void
22922 {
22926 {
22930 }
22932 {
22934 {
22937 }
22938 else
22939 {
22940 /* Register the (value) argument pack as a specialization of
22941 TMPL_PARM, then move on. */
22944 }
22945 }
22947 }
22949 /* Produce the definition of D, a _DECL generated from a template. If
22950 DEFER_OK is true, then we don't have to actually do the
22951 instantiation now; we just have to do it sometime. Normally it is
22952 an error if this is an explicit instantiation but D is undefined.
22953 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
22954 instantiated class template. */
22956 tree
22958 {
22960 tree gen_args;
22961 tree args;
22962 tree td;
22963 tree code_pattern;
22964 tree spec;
22965 tree gen_tmpl;
22973 /* This function should only be used to instantiate templates for
22974 functions and static member variables. */
22977 /* A concept is never instantiated. */
22980 /* Variables are never deferred; if instantiation is required, they
22981 are instantiated right away. That allows for better code in the
22982 case that an expression refers to the value of the variable --
22983 if the variable has a constant value the referring expression can
22984 take advantage of that fact. */
22988 /* Don't instantiate cloned functions. Instead, instantiate the
22989 functions they cloned. */
22997 /* D has already been instantiated or explicitly specialized, so
22998 there's nothing for us to do here.
23000 It might seem reasonable to check whether or not D is an explicit
23001 instantiation, and, if so, stop here. But when an explicit
23002 instantiation is deferred until the end of the compilation,
23003 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
23004 the instantiation. */
23007 /* Check to see whether we know that this template will be
23008 instantiated in some other file, as with "extern template"
23009 extension. */
23012 /* In general, we do not instantiate such templates. */
23020 /* We should already have the extra args. */
23023 /* And what's in the hash table should match D. */
23027 /* This needs to happen before any tsubsting. */
23033 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
23034 for the instantiation. */
23039 {
23040 /* Look up an explicit specialization, if any. */
23044 {
23047 }
23048 }
23052 /* We should never be trying to instantiate a member of a class
23053 template or partial specialization. */
23058 /* In the case of a friend template whose definition is provided
23059 outside the class, we may have too many arguments. Drop the
23060 ones we don't need. The same is true for specializations. */
23061 args = get_innermost_template_args
23065 {
23071 }
23072 else
23073 {
23078 else
23080 }
23082 /* We may be in the middle of deferred access check. Disable it now. */
23085 /* Unless an explicit instantiation directive has already determined
23086 the linkage of D, remember that a definition is available for
23087 this entity. */
23097 /* If D is a member of an explicitly instantiated class template,
23098 and no definition is available, treat it like an implicit
23099 instantiation. */
23102 {
23103 /* Leave linkage flags alone on instantiations with anonymous
23104 visibility. */
23106 {
23109 }
23111 }
23113 /* Defer all other templates, unless we have been explicitly
23114 forbidden from doing so. */
23116 template. */
23117 ! pattern_defined
23118 /* If it's OK to postpone instantiation, do so. */
23119 || defer_ok
23120 /* If this is a static data member that will be defined
23121 elsewhere, we don't want to instantiate the entire data
23122 member, but we do want to instantiate the initializer so that
23123 we can substitute that elsewhere. */
23125 /* Handle here a deleted function too, avoid generating
23126 its body (c++/61080). */
23128 {
23129 /* The definition of the static data member is now required so
23130 we must substitute the initializer. */
23134 {
23135 tree ns;
23136 tree init;
23145 args,
23148 /* If instantiating the initializer involved instantiating this
23149 again, don't call cp_finish_decl twice. */
23151 {
23152 /* Make sure the initializer is still constant, in case of
23153 circular dependency (template/instantiate6.C). */
23154 const_init
23158 LOOKUP_ONLYCONVERTING);
23159 }
23163 }
23165 /* We restore the source position here because it's used by
23166 add_pending_template. */
23172 /* [temp.explicit]
23174 The definition of a non-exported function template, a
23175 non-exported member function template, or a non-exported
23176 member function or static data member of a class template
23177 shall be present in every translation unit in which it is
23178 explicitly instantiated. */
23182 /* If we're in unevaluated context, we just wanted to get the
23183 constant value; this isn't an odr use, so don't queue
23184 a full instantiation. */
23187 /* ??? Historically, we have instantiated inline functions, even
23188 when marked as "extern template". */
23192 }
23193 /* Tell the repository that D is available in this translation unit
23194 -- and see if it is supposed to be instantiated here. */
23196 {
23197 /* In a PCH file, despite the fact that the repository hasn't
23198 requested instantiation in the PCH it is still possible that
23199 an instantiation will be required in a file that includes the
23200 PCH. */
23203 /* Instantiate inline functions so that the inliner can do its
23204 job, even though we'll not be emitting a copy of this
23205 function. */
23208 }
23211 tree fn_context;
23222 else
23223 {
23227 }
23229 /* Mark D as instantiated so that recursive calls to
23230 instantiate_decl do not try to instantiate it again. */
23233 /* Regenerate the declaration in case the template has been modified
23234 by a subsequent redeclaration. */
23237 /* We already set the file and line above. Reset them now in case
23238 they changed as a result of calling regenerate_decl_from_template. */
23242 {
23243 tree init;
23246 /* Clear out DECL_RTL; whatever was there before may not be right
23247 since we've reset the type of the declaration. */
23251 /* The initializer is placed in DECL_INITIAL by
23252 regenerate_decl_from_template so we don't need to
23253 push/pop_access_scope again here. Pull it out so that
23254 cp_finish_decl can process it. */
23259 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
23260 initializer. That function will defer actual emission until
23261 we have a chance to determine linkage. */
23264 /* Enter the scope of D so that access-checking works correctly. */
23277 }
23281 {
23282 /* Set up the list of local specializations. */
23286 /* Set up context. */
23290 else
23293 /* Some typedefs referenced from within the template code need to be
23294 access checked at template instantiation time, i.e now. These
23295 types were added to the template at parsing time. Let's get those
23296 and perform the access checks then. */
23298 args);
23300 /* Create substitution entries for the parameters. */
23303 /* Substitute into the body of the function. */
23307 else
23308 {
23313 /* Set the current input_location to the end of the function
23314 so that finish_function knows where we are. */
23315 input_location
23318 /* Remember if we saw an infinite loop in the template. */
23319 current_function_infinite_loop
23321 }
23323 /* Finish the function. */
23327 else
23328 {
23331 }
23335 }
23337 /* We're not deferring instantiation any more. */
23342 else
23348 out:
23357 }
23359 /* Run through the list of templates that we wish we could
23360 instantiate, and instantiate any we can. RETRIES is the
23361 number of times we retry pending template instantiation. */
23363 void
23365 {
23369 /* Instantiating templates may trigger vtable generation. This in turn
23370 may require further template instantiations. We place a limit here
23371 to avoid infinite loop. */
23373 {
23377 "template instantiation depth exceeds maximum of %d"
23378 " instantiating %q+D, possibly from virtual table generation"
23382 /* Pretend that we defined it. */
23385 }
23387 do
23388 {
23393 {
23398 {
23400 {
23415 }
23418 }
23419 else
23420 {
23423 {
23424 instantiation
23430 }
23434 }
23437 /* If INSTANTIATION has been instantiated, then we don't
23438 need to consider it again in the future. */
23440 else
23441 {
23444 }
23447 }
23449 }
23453 }
23455 /* Substitute ARGVEC into T, which is a list of initializers for
23456 either base class or a non-static data member. The TREE_PURPOSEs
23457 are DECLs, and the TREE_VALUEs are the initializer values. Used by
23458 instantiate_decl. */
23460 static tree
23462 {
23466 {
23467 tree decl;
23468 tree init;
23474 {
23475 tree expr;
23476 tree arg;
23478 /* Expand the base class expansion type into separate base
23479 classes. */
23481 tf_warning_or_error,
23482 NULL_TREE);
23486 /* We'll be building separate TREE_LISTs of arguments for
23487 each base. */
23493 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
23494 expand each argument in the TREE_VALUE of t. */
23501 /* VOID_TYPE_NODE is used to indicate
23502 value-initialization. */
23503 {
23506 }
23507 else
23508 {
23509 /* Substitute parameter packs into each argument in the
23510 TREE_LIST. */
23513 {
23514 tree expanded_exprs;
23516 /* Expand the argument. */
23518 expanded_exprs
23520 tf_warning_or_error,
23521 NULL_TREE);
23525 /* Prepend each of the expanded expressions to the
23526 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
23528 {
23533 }
23534 }
23537 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
23538 since we built them backwards. */
23540 {
23543 }
23544 }
23545 }
23548 {
23550 {
23554 }
23555 else
23556 {
23557 tree tmp;
23572 /* If we had an initializer but it instantiated to nothing,
23573 value-initialize the object. This will only occur when
23574 the initializer was a pack expansion where the parameter
23575 packs used in that expansion were of length zero. */
23578 }
23581 {
23585 }
23586 }
23587 }
23589 }
23591 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
23593 static void
23595 {
23600 else
23602 }
23604 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
23605 is the instantiation (which should have been created with
23606 start_enum) and ARGS are the template arguments to use. */
23608 static void
23610 {
23611 tree e;
23617 {
23618 tree value;
23619 tree decl;
23622 /* Note that in a template enum, the TREE_VALUE is the
23623 CONST_DECL, not the corresponding INTEGER_CST. */
23628 /* Give this enumeration constant the correct access. */
23631 /* Actually build the enumerator itself. Here we're assuming that
23632 enumerators can't have dependent attributes. */
23635 }
23645 }
23647 /* DECL is a FUNCTION_DECL that is a template specialization. Return
23648 its type -- but without substituting the innermost set of template
23649 arguments. So, innermost set of template parameters will appear in
23650 the type. */
23652 tree
23654 {
23655 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
23657 }
23659 /* Return truthvalue if we're processing a template different from
23660 the last one involved in diagnostics. */
23661 bool
23663 {
23665 }
23667 /* Remember current template involved in diagnostics. */
23668 void
23670 {
23672 }
23676 {
23678 }
23680 /* Return TRUE if current_function_decl is being instantiated, false
23681 otherwise. */
23683 bool
23685 {
23688 }
23690 /* [temp.param] Check that template non-type parm TYPE is of an allowable
23691 type. Return false for ok, true for disallowed. Issue error and
23692 inform messages under control of COMPLAIN. */
23694 static bool
23696 {
23711 /* A bound template template parm could later be instantiated to have a valid
23712 nontype parm type via an alias template. */
23718 {
23721 else
23723 type);
23724 }
23726 }
23728 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
23729 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
23731 static bool
23733 {
23734 tree scope;
23736 /* [temp.dep.type]
23738 A type is dependent if it is:
23740 -- a template parameter. Template template parameters are types
23741 for us (since TYPE_P holds true for them) so we handle
23742 them here. */
23746 /* -- a qualified-id with a nested-name-specifier which contains a
23747 class-name that names a dependent type or whose unqualified-id
23748 names a dependent type. */
23752 /* An alias template specialization can be dependent even if the
23753 resulting type is not. */
23757 /* -- a cv-qualified type where the cv-unqualified type is
23758 dependent.
23759 No code is necessary for this bullet; the code below handles
23760 cv-qualified types, and we don't want to strip aliases with
23761 TYPE_MAIN_VARIANT because of DR 1558. */
23762 /* -- a compound type constructed from any dependent type. */
23772 {
23773 tree arg_type;
23778 arg_type;
23783 /* A value-dependent noexcept-specifier makes the type dependent. */
23786 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
23787 affect overload resolution and treating it as dependent breaks
23788 things. */
23793 }
23794 /* -- an array type constructed from any dependent type or whose
23795 size is specified by a constant expression that is
23796 value-dependent.
23798 We checked for type- and value-dependence of the bounds in
23799 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
23801 {
23806 }
23808 /* -- a template-id in which either the template name is a template
23809 parameter ... */
23812 /* ... or any of the template arguments is a dependent type or
23813 an expression that is type-dependent or value-dependent. */
23815 && (any_dependent_template_arguments_p
23819 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
23820 dependent; if the argument of the `typeof' expression is not
23821 type-dependent, then it should already been have resolved. */
23827 /* A template argument pack is dependent if any of its packed
23828 arguments are. */
23830 {
23836 }
23838 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
23839 be template parameters. */
23846 /* The standard does not specifically mention types that are local
23847 to template functions or local classes, but they should be
23848 considered dependent too. For example:
23850 template <int I> void f() {
23851 enum E { a = I };
23852 S<sizeof (E)> s;
23853 }
23855 The size of `E' cannot be known until the value of `I' has been
23856 determined. Therefore, `E' must be considered dependent. */
23860 /* Don't use type_dependent_expression_p here, as it can lead
23861 to infinite recursion trying to determine whether a lambda
23862 nested in a lambda is dependent (c++/47687). */
23866 && (any_dependent_template_arguments_p
23870 /* Other types are non-dependent. */
23872 }
23874 /* Returns TRUE if TYPE is dependent, in the sense of
23875 [temp.dep.type]. Note that a NULL type is considered dependent. */
23877 bool
23879 {
23880 /* If there are no template parameters in scope, then there can't be
23881 any dependent types. */
23883 {
23884 /* If we are not processing a template, then nobody should be
23885 providing us with a dependent type. */
23889 }
23891 /* If the type is NULL, we have not computed a type for the entity
23892 in question; in that case, the type is dependent. */
23896 /* Erroneous types can be considered non-dependent. */
23900 /* Getting here with global_type_node means we improperly called this
23901 function on the TREE_TYPE of an IDENTIFIER_NODE. */
23904 /* If we have not already computed the appropriate value for TYPE,
23905 do so now. */
23907 {
23910 }
23913 }
23915 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
23916 lookup. In other words, a dependent type that is not the current
23917 instantiation. */
23919 bool
23921 {
23924 }
23926 /* T is a SCOPE_REF; return whether we need to consider it
23927 instantiation-dependent so that we can check access at instantiation
23928 time even though we know which member it resolves to. */
23930 static bool
23932 {
23938 else
23940 }
23942 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
23943 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
23944 expression. */
23946 /* Note that this predicate is not appropriate for general expressions;
23947 only constant expressions (that satisfy potential_constant_expression)
23948 can be tested for value dependence. */
23950 bool
23952 {
23956 /* A type-dependent expression is also value-dependent. */
23961 {
23963 /* A dependent member function of the current instantiation. */
23967 /* A dependent member function of the current instantiation. */
23974 /* A name that has not been looked up -- must be dependent. */
23978 /* A non-type template parm. */
23982 /* A non-type template parm. */
23988 /* A constant with literal type and is initialized
23989 with an expression that is value-dependent. */
23991 /* FIXME cp_finish_decl doesn't fold reference initializers. */
23995 {
23999 }
24008 /* These expressions are value-dependent if the type to which
24009 the cast occurs is dependent or the expression being casted
24010 is value-dependent. */
24011 {
24017 /* A functional cast has a list of operands. */
24020 {
24021 /* If there are no operands, it must be an expression such
24022 as "int()". This should not happen for aggregate types
24023 because it would form non-constant expressions. */
24028 }
24034 }
24039 /* FALLTHRU */
24042 /* A `sizeof' expression is value-dependent if the operand is
24043 type-dependent or is a pack expansion. */
24052 /* An 'encode' expression is value-dependent if the operand is
24053 type-dependent. */
24062 /* All instantiation-dependent expressions should also be considered
24063 value-dependent. */
24071 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
24072 is value-dependent. */
24073 {
24082 }
24085 {
24102 }
24113 {
24117 }
24120 /* Treat all requires-expressions as value-dependent so
24121 we don't try to fold them. */
24128 {
24135 {
24137 /* In a call to a constexpr member function, look through the
24138 implicit ADDR_EXPR on the object argument so that it doesn't
24139 cause the call to be considered value-dependent. We also
24140 look through it in potential_constant_expression. */
24147 }
24149 }
24155 {
24157 tree val;
24164 }
24167 /* Treat a GNU statement expression as dependent to avoid crashing
24168 under instantiate_non_dependent_expr; it can't be constant. */
24172 /* A constant expression is value-dependent if any subexpression is
24173 value-dependent. */
24175 {
24182 {
24186 {
24189 /* In some cases, some of the operands may be missing.
24190 (For example, in the case of PREDECREMENT_EXPR, the
24191 amount to increment by may be missing.) That doesn't
24192 make the expression dependent. */
24195 }
24196 }
24200 }
24202 }
24204 /* The expression is not value-dependent. */
24206 }
24208 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
24209 [temp.dep.expr]. Note that an expression with no type is
24210 considered dependent. Other parts of the compiler arrange for an
24211 expression with type-dependent subexpressions to have no type, so
24212 this function doesn't have to be fully recursive. */
24214 bool
24216 {
24223 /* An unresolved name is always dependent. */
24229 /* A fold expression is type-dependent. */
24236 /* Some expression forms are never type-dependent. */
24250 /* The types of these expressions depends only on the type to which
24251 the cast occurs. */
24260 /* The types of these expressions depends only on the type created
24261 by the expression. */
24264 {
24265 /* For NEW_EXPR tree nodes created inside a template, either
24266 the object type itself or a TREE_LIST may appear as the
24267 operand 1. */
24270 /* This is an array type. We need to check array dimensions
24271 as well. */
24273 || value_dependent_expression_p
24275 else
24277 }
24280 {
24284 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
24285 contains an identifier associated by name lookup with one or more
24286 declarations declared with a dependent type, or...a
24287 nested-name-specifier or qualified-id that names a member of an
24288 unknown specialization. */
24291 }
24301 {
24302 tree elt;
24306 {
24309 }
24311 }
24313 /* A static data member of the current instantiation with incomplete
24314 array type is type-dependent, as the definition and specializations
24315 can have different bounds. */
24322 /* An array of unknown bound depending on a variadic parameter, eg:
24324 template<typename... Args>
24325 void foo (Args... args)
24326 {
24327 int arr[] = { args... };
24328 }
24330 template<int... vals>
24331 void bar ()
24332 {
24333 int arr[] = { vals... };
24334 }
24336 If the array has no length and has an initializer, it must be that
24337 we couldn't determine its length in cp_complete_array_type because
24338 it is dependent. */
24346 /* A function or variable template-id is type-dependent if it has any
24347 dependent template arguments. */
24351 {
24352 /* Consider the innermost template arguments, since those are the ones
24353 that come from the template-id; the template arguments for the
24354 enclosing class do not make it type-dependent unless they are used in
24355 the type of the decl. */
24357 && (any_dependent_template_arguments_p
24360 }
24362 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
24363 type-dependent. Checking this is important for functions with auto return
24364 type, which looks like a dependent type. */
24372 {
24376 }
24378 /* Always dependent, on the number of arguments if nothing else. */
24383 {
24388 {
24394 }
24395 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
24400 {
24405 }
24408 {
24415 }
24425 }
24429 /* Dependent type attributes might not have made it from the decl to
24430 the type yet. */
24436 }
24438 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
24439 type-dependent if the expression refers to a member of the current
24440 instantiation and the type of the referenced member is dependent, or the
24441 class member access expression refers to a member of an unknown
24442 specialization.
24444 This function returns true if the OBJECT in such a class member access
24445 expression is of an unknown specialization. */
24447 bool
24449 {
24450 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
24451 dependent. */
24456 }
24458 /* walk_tree callback function for instantiation_dependent_expression_p,
24459 below. Returns non-zero if a dependent subexpression is found. */
24461 static tree
24464 {
24466 {
24467 /* We don't have to worry about decltype currently because decltype
24468 of an instantiation-dependent expr is a dependent type. This
24469 might change depending on the resolution of DR 1172. */
24472 }
24475 {
24476 /* Don't treat an argument list as dependent just because it has no
24477 TREE_TYPE. */
24485 /* Handle expressions with type operands. */
24490 {
24495 {
24498 else
24499 {
24502 }
24503 }
24505 }
24509 /* In a template, finish_class_member_access_expr creates a
24510 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
24511 type-dependent, so that we can check access control at
24512 instantiation time (PR 42277). See also Core issue 1273. */
24519 else
24522 /* Treat statement-expressions as dependent. */
24526 /* Treat requires-expressions as dependent. */
24531 /* Treat calls to function concepts as dependent. */
24537 /* And variable concepts. */
24544 }
24548 else
24550 }
24552 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
24553 sense defined by the ABI:
24555 "An expression is instantiation-dependent if it is type-dependent
24556 or value-dependent, or it has a subexpression that is type-dependent
24557 or value-dependent."
24559 Except don't actually check value-dependence for unevaluated expressions,
24560 because in sizeof(i) we don't care about the value of i. Checking
24561 type-dependence will in turn check value-dependence of array bounds/template
24562 arguments as needed. */
24564 bool
24566 {
24567 tree result;
24578 }
24580 /* As above, but also check value-dependence of the expression as a whole. */
24582 bool
24584 {
24587 }
24589 /* Like type_dependent_expression_p, but it also works while not processing
24590 a template definition, i.e. during substitution or mangling. */
24592 bool
24594 {
24600 }
24602 /* Returns TRUE if ARGS contains a type-dependent expression. */
24604 bool
24606 {
24608 tree arg;
24611 {
24614 }
24616 }
24618 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24619 expressions) contains any type-dependent expressions. */
24621 bool
24623 {
24629 }
24631 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24632 expressions) contains any value-dependent expressions. */
24634 bool
24636 {
24642 }
24644 /* Returns TRUE if the ARG (a template argument) is dependent. */
24646 bool
24648 {
24652 /* Assume a template argument that was wrongly written by the user
24653 is dependent. This is consistent with what
24654 any_dependent_template_arguments_p [that calls this function]
24655 does. */
24665 {
24668 /* A member template of a dependent class is not necessarily
24669 type-dependent, but it is a dependent template argument because it
24670 will be a member of an unknown specialization to that template. */
24673 }
24675 {
24679 {
24682 }
24685 }
24688 else
24691 }
24693 /* Returns true if ARGS (a collection of template arguments) contains
24694 any types that require structural equality testing. */
24696 bool
24698 {
24708 {
24711 {
24717 {
24718 /* Look inside the argument pack. */
24721 }
24724 {
24737 }
24738 }
24739 }
24742 }
24744 /* Returns true if ARGS (a collection of template arguments) contains
24745 any dependent arguments. */
24747 bool
24749 {
24759 {
24764 }
24767 }
24769 /* Returns TRUE if the template TMPL is type-dependent. */
24771 bool
24773 {
24775 {
24780 }
24782 /* Template template parameters are dependent. */
24786 /* So are names that have not been looked up. */
24790 }
24792 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
24794 bool
24796 {
24799 }
24801 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
24802 are dependent. */
24804 bool
24806 {
24813 {
24835 {
24839 }
24843 {
24847 {
24852 }
24853 }
24854 }
24857 }
24859 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
24860 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
24861 no such TYPE can be found. Note that this function peers inside
24862 uninstantiated templates and therefore should be used only in
24863 extremely limited situations. ONLY_CURRENT_P restricts this
24864 peering to the currently open classes hierarchy (which is required
24865 when comparing types). */
24867 tree
24869 {
24870 tree scope;
24871 tree name;
24872 tree decl;
24874 tree pushed_scope;
24875 tree result;
24880 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
24881 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
24882 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
24883 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
24884 identifier of the TYPENAME_TYPE anymore.
24885 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
24886 TYPENAME_TYPE instead, we avoid messing up with a possible
24887 typedef variant case. */
24890 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
24891 it first before we can figure out what NAME refers to. */
24893 {
24895 /* Given a class template A with a dependent base with nested type C,
24896 typedef typename A::C::C C will land us here, as trying to resolve
24897 the initial A::C leads to the local C typedef, which leads back to
24898 A::C::C. So we break the recursion now. */
24900 else
24902 }
24903 /* If we don't know what SCOPE refers to, then we cannot resolve the
24904 TYPENAME_TYPE. */
24907 /* If this is a typedef, we don't want to look inside (c++/11987). */
24910 /* If SCOPE isn't the template itself, it will not have a valid
24911 TYPE_FIELDS list. */
24913 /* scope is either the template itself or a compatible instantiation
24914 like X<T>, so look up the name in the original template. */
24916 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
24918 /* If scope has no fields, it can't be a current instantiation. Check this
24919 before currently_open_class to avoid infinite recursion (71515). */
24922 /* If the SCOPE is not the current instantiation, there's no reason
24923 to look inside it. */
24926 /* Enter the SCOPE so that name lookup will be resolved as if we
24927 were in the class definition. In particular, SCOPE will no
24928 longer be considered a dependent type. */
24930 /* Look up the declaration. */
24932 tf_warning_or_error);
24936 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
24937 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
24943 {
24947 }
24950 {
24951 /* Obtain the template and the arguments. */
24954 {
24955 /* We get here with a plain identifier because a previous tentative
24956 parse of the nested-name-specifier as part of a ptr-operator saw
24957 ::template X<A>. The use of ::template is necessary in a
24958 ptr-operator, but wrong in a declarator-id.
24960 [temp.names]: In a qualified-id of a declarator-id, the keyword
24961 template shall not appear at the top level. */
24965 }
24967 /* Instantiate the template. */
24973 }
24975 /* Leave the SCOPE. */
24979 /* If we failed to resolve it, return the original typename. */
24983 /* If lookup found a typename type, resolve that too. */
24985 {
24986 /* Ill-formed programs can cause infinite recursion here, so we
24987 must catch that. */
24991 }
24993 /* Qualify the resulting type. */
24999 }
25001 /* EXPR is an expression which is not type-dependent. Return a proxy
25002 for EXPR that can be used to compute the types of larger
25003 expressions containing EXPR. */
25005 tree
25007 {
25009 tree inner_expr;
25011 /* When checking, try to get a constant value for all non-dependent
25012 expressions in order to expose bugs in *_dependent_expression_p
25013 and constexpr. This can affect code generation, see PR70704, so
25014 only do this for -fchecking=2. */
25017 /* Don't do this during nsdmi parsing as it can lead to
25018 unexpected recursive instantiations. */
25020 /* Don't do this during concept expansion either and for
25021 the same reason. */
25027 /* Preserve OVERLOADs; the functions must be available to resolve
25028 types. */
25039 /* There is no need to return a proxy for a variable. */
25042 /* Preserve string constants; conversions from string constants to
25043 "char *" are allowed, even though normally a "const char *"
25044 cannot be used to initialize a "char *". */
25047 /* Preserve void and arithmetic constants, as an optimization -- there is no
25048 reason to create a new node. */
25053 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
25054 There is at least one place where we want to know that a
25055 particular expression is a throw-expression: when checking a ?:
25056 expression, there are special rules if the second or third
25057 argument is a throw-expression. */
25061 /* Don't wrap an initializer list, we need to be able to look inside. */
25065 /* Don't wrap a dummy object, we need to be able to test for it. */
25084 /* If the type is unknown, it can't really be non-dependent */
25087 /* Otherwise, build a NON_DEPENDENT_EXPR. */
25089 }
25091 /* ARGS is a vector of expressions as arguments to a function call.
25092 Replace the arguments with equivalent non-dependent expressions.
25093 This modifies ARGS in place. */
25095 void
25097 {
25099 tree arg;
25102 {
25106 }
25107 }
25109 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
25110 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
25111 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
25113 static tree
25115 {
25129 }
25131 tree
25133 {
25135 }
25137 tree
25139 {
25141 }
25143 /* Return a C++17 deduction placeholder for class template TMPL. */
25145 tree
25147 {
25151 }
25153 /* True iff T is a C++17 class template deduction placeholder. */
25155 bool
25157 {
25159 }
25161 /* Make a "constrained auto" type-specifier. This is an
25162 auto type with constraints that must be associated after
25163 deduction. The constraint is formed from the given
25164 CONC and its optional sequence of arguments, which are
25165 non-null if written as partial-concept-id. */
25167 tree
25169 {
25172 /* Build the constraint. */
25180 /* Our canonical type depends on the constraint. */
25183 /* Attach the constraint to the type declaration. */
25186 }
25188 /* Given type ARG, return std::initializer_list<ARG>. */
25190 static tree
25192 {
25196 {
25200 "deducing from brace-enclosed initializer list"
25204 }
25210 }
25212 /* Replace auto in TYPE with std::initializer_list<auto>. */
25214 static tree
25216 {
25223 }
25225 /* Hash traits for hashing possibly constrained 'auto'
25226 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
25229 {
25232 };
25234 /* Hash the 'auto' T. */
25236 inline hashval_t
25238 {
25240 /* Matching constrained-type-specifiers denote the same template
25241 parameter, so hash the constraint. */
25243 else
25244 /* But unconstrained autos are all separate, so just hash the pointer. */
25246 }
25248 /* Compare two 'auto's. */
25252 {
25259 /* Two unconstrained autos are distinct. */
25264 }
25266 /* for_each_template_parm callback for extract_autos: if t is a (possibly
25267 constrained) auto, add it to the vector. */
25269 static int
25271 {
25274 {
25275 /* All the autos were built with index 0; fix that up now. */
25279 /* If this is a repeated constrained-type-specifier, use the index we
25280 chose before. */
25282 else
25283 {
25284 /* Otherwise this is new, so use the current count. */
25287 }
25289 }
25291 /* Always keep walking. */
25293 }
25295 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
25296 says they can appear anywhere in the type. */
25298 static tree
25300 {
25309 {
25314 }
25317 }
25319 /* The stem for deduction guide names. */
25322 /* Return the name for a deduction guide for class template TMPL. */
25324 tree
25326 {
25337 }
25339 /* True if NAME is the name of a deduction guide. */
25341 bool
25343 {
25347 }
25349 /* True if FN is a deduction guide. */
25351 bool
25353 {
25358 }
25360 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
25362 bool
25364 {
25371 }
25373 /* True if FN is a guide generated from a constructor template. */
25375 bool
25377 {
25385 }
25387 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
25388 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
25389 template parameter types. Note that the handling of template template
25390 parameters relies on current_template_parms being set appropriately for the
25391 new template. */
25393 static tree
25396 {
25399 tree newtype;
25402 {
25409 }
25410 else
25414 tree newdecl
25419 tree newidx;
25422 {
25432 {
25437 // First create a copy (ttargs) of tsubst_args with an
25438 // additional level for the template template parameter's own
25439 // template parameters (ttparms).
25440 tree ttparms = (INNERMOST_TEMPLATE_PARMS
25448 // Substitute ttargs into ttparms to fix references to
25449 // other template parameters.
25451 complain);
25452 // Now substitute again with args based on tparms, to reduce
25453 // the level of the ttparms.
25456 complain);
25457 // Finally, tack the adjusted parms onto tparms.
25459 current_template_parms);
25461 }
25462 }
25463 else
25464 {
25466 tree newconst
25478 }
25481 }
25483 /* Returns a C++17 class deduction guide template based on the constructor
25484 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
25485 guide, or REFERENCE_TYPE for an implicit copy/move guide. */
25487 static tree
25489 {
25493 location_t loc;
25497 {
25501 {
25504 }
25505 else
25515 }
25516 else
25517 {
25520 fn_tmpl
25530 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
25531 fully specialized args for the enclosing class. Strip those off, as
25532 the deduction guide won't have those template parameters. */
25535 /* Discard the 'this' parameter. */
25543 {
25546 /* For a member template constructor, we need to flatten the two
25547 template parameter lists into one, and then adjust the function
25548 signature accordingly. This gets...complicated. */
25551 /* For a member template we should have two levels of parms/args, one
25552 for the class and one for the constructor. We stripped
25553 specialized args for further enclosing classes above. */
25557 /* Template args for translating references to the two-level template
25558 parameters into references to the one-level template parameters we
25559 are creating. */
25564 /* Template parms for the constructor template. */
25567 /* Template parms for the class template. */
25571 /* Template parms for the deduction guide start as a copy of the
25572 template parms for the class. We set current_template_parms for
25573 lookup_template_class_1. */
25579 /* Now we need to rewrite the constructor parms to append them to the
25580 class parms. */
25582 {
25597 }
25599 /* Now we have a final set of template parms to substitute into the
25600 function signature. */
25609 }
25611 }
25614 {
25615 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
25619 }
25623 FUNCTION_DECL,
25640 }
25642 /* Deduce template arguments for the class template placeholder PTYPE for
25643 template TMPL based on the initializer INIT, and return the resulting
25644 type. */
25646 static tree
25648 tsubst_flags_t complain)
25649 {
25651 {
25652 /* We should have handled this in the caller. */
25658 }
25669 {
25672 {
25673 /* As an exception, the first phase in 16.3.1.7 (considering the
25674 initializer list as a single argument) is omitted if the
25675 initializer list consists of a single expression of type cv U,
25676 where U is a specialization of C or a class derived from a
25677 specialization of C. */
25688 }
25691 else
25693 }
25694 else
25705 /* Prune explicit deduction guides in copy-initialization context. */
25707 {
25713 {
25714 /* Found a nonconverting guide, prune the candidates. */
25721 }
25722 }
25727 {
25730 }
25733 // FIXME cache artificial deduction guides
25735 {
25740 else
25744 }
25748 /* If this is list-initialization and the class has a list constructor, first
25749 try deducing from the list as a single argument, as [over.match.list]. */
25753 {
25757 }
25759 {
25765 {
25766 /* That didn't work, now try treating the list as a sequence of
25767 arguments. */
25770 }
25771 }
25773 /* Maybe generate an implicit deduction guide. */
25775 {
25779 /* Generate a copy guide. */
25782 /* Generate a default guide. */
25786 {
25789 }
25790 }
25793 {
25795 " of %qT, as it has no non-explicit deduction guides or "
25798 }
25800 {
25804 }
25807 {
25811 }
25814 {
25824 }
25829 }
25831 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25832 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
25834 tree
25836 {
25838 tf_warning_or_error,
25839 adc_unspecified);
25840 }
25842 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25843 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
25844 The CONTEXT determines the context in which auto deduction is performed
25845 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
25846 OUTER_TARGS are used during template argument deduction
25847 (context == adc_unify) to properly substitute the result, and is ignored
25848 in other contexts.
25850 For partial-concept-ids, extra args may be appended to the list of deduced
25851 template arguments prior to determining constraint satisfaction. */
25853 tree
25857 {
25858 tree targs;
25865 /* Defining a subset of type-dependent expressions that we can deduce
25866 from ahead of time isn't worth the trouble. */
25870 /* C++17 class template argument deduction. */
25874 /* Nothing we can do with this, even in deduction context. */
25877 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
25878 with either a new invented type template parameter U or, if the
25879 initializer is a braced-init-list (8.5.4), with
25880 std::initializer_list<U>. */
25882 {
25887 else
25888 {
25890 {
25894 "for deduction to %<std::initializer_list%>, use copy-"
25896 }
25898 }
25899 }
25910 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
25911 and initializer has array type, deduce cv-qualified array type. */
25913 complain);
25915 {
25924 {
25928 }
25929 }
25930 else
25931 {
25933 tree tparms;
25937 else
25938 {
25942 }
25949 {
25951 /* Try again at instantiation time. */
25955 /* If type is error_mark_node a diagnostic must have been
25956 emitted by now. Also, having a mention to '<type error>'
25957 in the diagnostic is not really useful to the user. */
25958 {
25962 else
25967 }
25969 }
25970 }
25972 /* Check any placeholder constraints against the deduced type. */
25975 {
25976 /* Use the deduced type to check the associated constraints. If we
25977 have a partial-concept-id, rebuild the argument list so that
25978 we check using the extra arguments. */
25982 {
25985 }
25986 else
25989 {
25991 {
25993 {
26011 }
26013 }
26015 }
26016 }
26022 }
26024 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
26025 result. */
26027 tree
26029 {
26031 {
26037 /* In an abbreviated function template we didn't know we were dealing
26038 with a function template when we saw the auto return type, so update
26039 it to have the correct level. */
26041 }
26043 }
26045 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
26046 'decltype(auto)' or a deduced class template. */
26048 bool
26050 {
26056 else
26058 }
26060 /* for_each_template_parm callback for type_uses_auto. */
26062 int
26064 {
26066 }
26068 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
26069 a use of `auto'. Returns NULL_TREE otherwise. */
26071 tree
26073 {
26077 {
26078 /* The Concepts TS allows multiple autos in one type-specifier; just
26079 return the first one we find, do_auto_deduction will collect all of
26080 them. */
26084 else
26086 }
26087 else
26089 }
26091 /* For a given template T, return the vector of typedefs referenced
26092 in T for which access check is needed at T instantiation time.
26093 T is either a FUNCTION_DECL or a RECORD_TYPE.
26094 Those typedefs were added to T by the function
26095 append_type_to_template_for_access_check. */
26099 {
26100 tree ti;
26111 {
26116 }
26119 }
26121 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
26122 tied to T. That list of typedefs will be access checked at
26123 T instantiation time.
26124 T is either a FUNCTION_DECL or a RECORD_TYPE.
26125 TYPE_DECL is a TYPE_DECL node representing a typedef.
26126 SCOPE is the scope through which TYPE_DECL is accessed.
26127 LOCATION is the location of the usage point of TYPE_DECL.
26129 This function is a subroutine of
26130 append_type_to_template_for_access_check. */
26132 static void
26134 tree type_decl,
26135 tree scope,
26136 location_t location)
26137 {
26138 qualified_typedef_usage_t typedef_usage;
26139 tree ti;
26146 && type_decl
26160 }
26162 /* Append TYPE_DECL to the template TEMPL.
26163 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
26164 At TEMPL instanciation time, TYPE_DECL will be checked to see
26165 if it can be accessed through SCOPE.
26166 LOCATION is the location of the usage point of TYPE_DECL.
26168 e.g. consider the following code snippet:
26170 class C
26171 {
26172 typedef int myint;
26173 };
26175 template<class U> struct S
26176 {
26177 C::myint mi; // <-- usage point of the typedef C::myint
26178 };
26180 S<char> s;
26182 At S<char> instantiation time, we need to check the access of C::myint
26183 In other words, we need to check the access of the myint typedef through
26184 the C scope. For that purpose, this function will add the myint typedef
26185 and the scope C through which its being accessed to a list of typedefs
26186 tied to the template S. That list will be walked at template instantiation
26187 time and access check performed on each typedefs it contains.
26188 Note that this particular code snippet should yield an error because
26189 myint is private to C. */
26191 void
26193 tree type_decl,
26194 tree scope,
26195 location_t location)
26196 {
26202 /* Make sure we don't append the type to the template twice. */
26209 }
26211 /* Convert the generic type parameters in PARM that match the types given in the
26212 range [START_IDX, END_IDX) from the current_template_parms into generic type
26213 packs. */
26215 tree
26217 {
26228 {
26229 /* Create a distinct parameter pack type from the current parm and add it
26230 to the replacement args to tsubst below into the generic function
26231 parameter. */
26246 }
26252 /* If there are more levels then build up the replacement with the outer
26253 template parms. */
26257 replacement);
26260 }
26262 /* Entries in the decl_constraint hash table. */
26264 {
26265 tree decl;
26266 tree ci;
26267 };
26269 /* Hashing function and equality for constraint entries. */
26271 {
26273 {
26275 }
26278 {
26280 }
26281 };
26283 /* A mapping from declarations to constraint information. Note that
26284 both templates and their underlying declarations are mapped to the
26285 same constraint information.
26287 FIXME: This is defined in pt.c because garbage collection
26288 code is not being generated for constraint.cc. */
26292 /* Returns the template constraints of declaration T. If T is not
26293 constrained, return NULL_TREE. Note that T must be non-null. */
26295 tree
26297 {
26308 else
26310 }
26312 /* Associate the given constraint information CI with the declaration
26313 T. If T is a template, then the constraints are associated with
26314 its underlying declaration. Don't build associations if CI is
26315 NULL_TREE. */
26317 void
26319 {
26331 }
26333 /* Remove the associated constraints of the declaration T. */
26335 void
26337 {
26346 }
26348 /* Memoized satisfaction results for declarations. This
26349 maps the pair (constraint_info, arguments) to the result computed
26350 by constraints_satisfied_p. */
26353 {
26354 tree ci;
26355 tree args;
26356 tree result;
26357 };
26359 /* Hashing function and equality for constraint entries. */
26362 {
26364 {
26367 }
26370 {
26372 }
26373 };
26375 /* Memoized satisfaction results for concept checks. */
26378 {
26379 tree tmpl;
26380 tree args;
26381 tree result;
26382 };
26384 /* Hashing function and equality for constraint entries. */
26387 {
26389 {
26391 }
26394 {
26399 }
26400 };
26405 /* Search for a memoized satisfaction result. Returns one of the
26406 truth value nodes if previously memoized, or NULL_TREE otherwise. */
26408 tree
26410 {
26415 else
26417 }
26419 /* Memoize the result of a satisfication test. Returns the saved result. */
26421 tree
26423 {
26430 }
26432 /* Search for a memoized satisfaction result for a concept. */
26434 tree
26436 {
26441 else
26443 }
26445 /* Memoize the result of a concept check. Returns the saved result. */
26447 tree
26449 {
26456 }
26460 /* Returns a prior concept specialization. This returns the substituted
26461 and normalized constraints defined by the concept. */
26463 tree
26465 {
26470 else
26472 }
26474 /* Save a concept expansion for later. */
26476 tree
26478 {
26485 }
26487 static hashval_t
26489 {
26498 }
26500 /* Compare the constraints of two subsumption entries. The LEFT1 and
26501 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
26502 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
26504 static bool
26506 {
26514 }
26516 /* Key/value pair for learning and memoizing subsumption results. This
26517 associates a pair of check constraints (including arguments) with
26518 a boolean value indicating the result. */
26521 {
26522 tree t1;
26523 tree t2;
26525 };
26527 /* Hashing function and equality for constraint entries. */
26530 {
26532 {
26534 }
26537 {
26542 }
26543 };
26547 /* Search for a previously cached subsumption result. */
26551 {
26556 else
26558 }
26560 /* Save a subsumption result. */
26562 bool
26564 {
26571 }
26573 /* Set up the hash table for constraint association. */
26575 void
26577 {
26586 }
26588 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
26589 0..N-1. */
26591 void
26593 {
26596 integer_type_node,
26597 NULL_TREE),
26601 }
26603 /* Set up the hash tables for template instantiations. */
26605 void
26607 {
26613 }
26615 /* Print stats about the template hash tables for -fstats. */
26617 void
26619 {
26628 }
26630 #if CHECKING_P
26634 /* Verify that build_non_dependent_expr () works, for various expressions,
26635 and that location wrappers don't affect the results. */
26637 static void
26639 {
26642 /* Verify constants, without and with location wrappers. */
26659 }
26661 /* Run all of the selftests within this file. */
26663 void
26665 {
26667 }