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1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2017 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". */
44 /* The type of functions taking a tree, and some additional data, and
45 returning an int. */
48 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
49 instantiations have been deferred, either because their definitions
50 were not yet available, or because we were putting off doing the work. */
54 };
69 /* Live only within one (recursive) call to tsubst_expr. We use
70 this to pass the statement expression node from the STMT_EXPR
71 to the EXPR_STMT that is its result. */
74 // -------------------------------------------------------------------------- //
75 // Local Specialization Stack
76 //
77 // Implementation of the RAII helper for creating new local
78 // specializations.
81 {
83 }
86 {
89 }
91 /* True if we've recursed into fn_type_unification too many times. */
95 {
96 tree tmpl;
97 tree args;
98 tree spec;
99 };
102 {
105 };
111 /* Contains canonical template parameter types. The vector is indexed by
112 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
113 TREE_LIST, whose TREE_VALUEs contain the canonical template
114 parameters of various types and levels. */
117 #define UNIFY_ALLOW_NONE 0
118 #define UNIFY_ALLOW_MORE_CV_QUAL 1
119 #define UNIFY_ALLOW_LESS_CV_QUAL 2
120 #define UNIFY_ALLOW_DERIVED 4
121 #define UNIFY_ALLOW_INTEGER 8
122 #define UNIFY_ALLOW_OUTER_LEVEL 16
123 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
124 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
127 tbr_incomplete_type,
128 tbr_ambiguous_baseclass,
129 tbr_success
130 };
153 tree);
210 location_t);
219 /* Make the current scope suitable for access checking when we are
220 processing T. T can be FUNCTION_DECL for instantiated function
221 template, VAR_DECL for static member variable, or TYPE_DECL for
222 alias template (needed by instantiate_decl). */
224 static void
226 {
234 else
238 {
239 saved_access_scope = tree_cons
242 }
243 }
245 /* Restore the scope set up by push_access_scope. T is the node we
246 are processing. */
248 static void
250 {
252 {
255 }
259 else
261 }
263 /* Do any processing required when DECL (a member template
264 declaration) is finished. Returns the TEMPLATE_DECL corresponding
265 to DECL, unless it is a specialization, in which case the DECL
266 itself is returned. */
268 tree
270 {
277 {
278 tree type;
286 {
290 }
292 }
296 {
298 {
301 }
302 else
304 }
305 else
309 }
311 /* Create a template info node. */
313 tree
315 {
320 }
322 /* Return the template info node corresponding to T, whatever T is. */
324 tree
326 {
348 }
350 /* Returns the template nesting level of the indicated class TYPE.
352 For example, in:
353 template <class T>
354 struct A
355 {
356 template <class U>
357 struct B {};
358 };
360 A<T>::B<U> has depth two, while A<T> has depth one.
361 Both A<T>::B<int> and A<int>::B<U> have depth one, if
362 they are instantiations, not specializations.
364 This function is guaranteed to return 0 if passed NULL_TREE so
365 that, for example, `template_class_depth (current_class_type)' is
366 always safe. */
368 int
370 {
374 {
385 else
387 }
390 }
392 /* Subroutine of maybe_begin_member_template_processing.
393 Returns true if processing DECL needs us to push template parms. */
395 static bool
397 {
403 }
405 /* Subroutine of maybe_begin_member_template_processing.
406 Push the template parms in PARMS, starting from LEVELS steps into the
407 chain, and ending at the beginning, since template parms are listed
408 innermost first. */
410 static void
412 {
420 current_template_parms
426 NULL);
428 {
437 {
444 /* Push the CONST_DECL. */
450 }
451 }
452 }
454 /* Restore the template parameter context for a member template, a
455 friend template defined in a class definition, or a non-template
456 member of template class. */
458 void
460 {
461 tree parms;
466 {
469 /* Disregard full specializations (c++/60999). */
472 }
475 {
480 {
483 }
486 }
488 /* Remember how many levels of template parameters we pushed so that
489 we can pop them later. */
491 }
493 /* Undo the effects of maybe_begin_member_template_processing. */
495 void
497 {
506 {
510 }
511 }
513 /* Return a new template argument vector which contains all of ARGS,
514 but has as its innermost set of arguments the EXTRA_ARGS. */
516 static tree
518 {
519 tree new_args;
537 }
539 /* Like add_to_template_args, but only the outermost ARGS are added to
540 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
541 (EXTRA_ARGS) levels are added. This function is used to combine
542 the template arguments from a partial instantiation with the
543 template arguments used to attain the full instantiation from the
544 partial instantiation. */
546 static tree
548 {
549 tree new_args;
551 /* If there are more levels of EXTRA_ARGS than there are ARGS,
552 something very fishy is going on. */
555 /* If *all* the new arguments will be the EXTRA_ARGS, just return
556 them. */
560 /* For the moment, we make ARGS look like it contains fewer levels. */
565 /* Now, we restore ARGS to its full dimensions. */
569 }
571 /* Return the N levels of innermost template arguments from the ARGS. */
573 tree
575 {
576 tree new_args;
582 /* If N is 1, just return the innermost set of template arguments. */
586 /* If we're not removing anything, just return the arguments we were
587 given. */
593 /* Make a new set of arguments, not containing the outer arguments. */
600 }
602 /* The inverse of get_innermost_template_args: Return all but the innermost
603 EXTRA_LEVELS levels of template arguments from the ARGS. */
605 static tree
607 {
608 tree new_args;
614 /* If N is 1, just return the outermost set of template arguments. */
618 /* If we're not removing anything, just return the arguments we were
619 given. */
624 /* Make a new set of arguments, not containing the inner arguments. */
631 }
633 /* We've got a template header coming up; push to a new level for storing
634 the parms. */
636 void
638 {
639 /* We use a non-tag-transparent scope here, which causes pushtag to
640 put tags in this scope, rather than in the enclosing class or
641 namespace scope. This is the right thing, since we want
642 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
643 global template class, push_template_decl handles putting the
644 TEMPLATE_DECL into top-level scope. For a nested template class,
645 e.g.:
647 template <class T> struct S1 {
648 template <class T> struct S2 {};
649 };
651 pushtag contains special code to call pushdecl_with_scope on the
652 TEMPLATE_DECL for S2. */
658 /* Add a dummy parameter level while we process the parameter list. */
659 current_template_parms
662 current_template_parms);
663 }
665 /* This routine is called when a specialization is declared. If it is
666 invalid to declare a specialization here, an error is reported and
667 false is returned, otherwise this routine will return true. */
669 static bool
671 {
674 /* [temp.expl.spec]
676 An explicit specialization shall be declared in the namespace of
677 which the template is a member, or, for member templates, in the
678 namespace of which the enclosing class or enclosing class
679 template is a member. An explicit specialization of a member
680 function, member class or static data member of a class template
681 shall be declared in the namespace of which the class template
682 is a member. */
684 {
687 }
689 /* [temp.expl.spec]
691 In an explicit specialization declaration for a member of a class
692 template or a member template that appears in namespace scope,
693 the member template and some of its enclosing class templates may
694 remain unspecialized, except that the declaration shall not
695 explicitly specialize a class member template if its enclosing
696 class templates are not explicitly specialized as well. */
698 {
701 }
704 }
706 /* We've just seen template <>. */
708 bool
710 {
714 }
716 /* Called at then end of processing a declaration preceded by
717 template<>. */
719 void
721 {
724 }
726 /* Any template <>'s that we have seen thus far are not referring to a
727 function specialization. */
729 void
731 {
734 }
736 /* We've just seen a template header. If SPECIALIZATION is nonzero,
737 it was of the form template <>. */
739 static void
741 {
743 template_header_count++;
744 }
746 /* We're beginning an explicit instantiation. */
748 void
750 {
753 }
756 void
758 {
761 }
763 /* An explicit specialization or partial specialization of TMPL is being
764 declared. Check that the namespace in which the specialization is
765 occurring is permissible. Returns false iff it is invalid to
766 specialize TMPL in the current namespace. */
768 static bool
770 {
773 /* [tmpl.expl.spec]
775 An explicit specialization shall be declared in a namespace enclosing the
776 specialized template. An explicit specialization whose declarator-id is
777 not qualified shall be declared in the nearest enclosing namespace of the
778 template, or, if the namespace is inline (7.3.1), any namespace from its
779 enclosing namespace set. */
782 {
785 }
790 /* Same or enclosing namespace. */
792 else
793 {
799 }
800 }
802 /* SPEC is an explicit instantiation. Check that it is valid to
803 perform this explicit instantiation in the current namespace. */
805 static void
807 {
808 tree ns;
810 /* DR 275: An explicit instantiation shall appear in an enclosing
811 namespace of its template. */
817 }
819 // Returns the type of a template specialization only if that
820 // specialization needs to be defined. Otherwise (e.g., if the type has
821 // already been defined), the function returns NULL_TREE.
822 static tree
824 {
825 // An implicit instantiation of an incomplete type implies
826 // the definition of a new class template.
827 //
828 // template<typename T>
829 // struct S;
830 //
831 // template<typename T>
832 // struct S<T*>;
833 //
834 // Here, S<T*> is an implicit instantiation of S whose type
835 // is incomplete.
839 // It can also be the case that TYPE is a completed specialization.
840 // Continuing the previous example, suppose we also declare:
841 //
842 // template<typename T>
843 // requires Integral<T>
844 // struct S<T*>;
845 //
846 // Here, S<T*> refers to the specialization S<T*> defined
847 // above. However, we need to differentiate definitions because
848 // we intend to define a new partial specialization. In this case,
849 // we rely on the fact that the constraints are different for
850 // this declaration than that above.
851 //
852 // Note that we also get here for injected class names and
853 // late-parsed template definitions. We must ensure that we
854 // do not create new type declarations for those cases.
856 {
860 // If there are no template parameters, this cannot be a new
861 // partial template specializtion?
865 // The injected-class-name is not a new partial specialization.
869 // If the constraints are not the same as those of the primary
870 // then, we can probably create a new specialization.
874 {
878 }
880 // Also, if there's a pre-existing specialization with matching
881 // constraints, then this also isn't new.
884 {
892 }
894 // Create a new type node (and corresponding type decl)
895 // for the newly declared specialization.
900 /* We only need a separate type node for storing the definition of this
901 partial specialization; uses of S<T*> are unconstrained, so all are
902 equivalent. So keep TYPE_CANONICAL the same. */
905 // Build the corresponding type decl.
911 }
914 }
916 /* The TYPE is being declared. If it is a template type, that means it
917 is a partial specialization. Do appropriate error-checking. */
919 tree
921 {
922 tree context;
927 /* A lambda that appears in specialization context is not itself a
928 specialization. */
933 {
937 }
942 {
948 else
951 }
953 {
954 /* This is for ordinary explicit specialization and partial
955 specialization of a template class such as:
957 template <> class C<int>;
959 or:
961 template <class T> class C<T*>;
963 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
966 {
973 {
978 }
979 }
985 /* Trying to define a specialization either without a template<> header
986 or in an inappropriate place. We've already given an error, so just
987 bail now so we don't actually define the specialization. */
989 }
995 {
996 /* This is for an explicit specialization of member class
997 template according to [temp.expl.spec/18]:
999 template <> template <class U> class C<int>::D;
1001 The context `C<int>' must be an implicit instantiation.
1002 Otherwise this is just a member class template declared
1003 earlier like:
1005 template <> class C<int> { template <class U> class D; };
1006 template <> template <class U> class C<int>::D;
1008 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1009 while in the second case, `C<int>::D' is a primary template
1010 and `C<T>::D' may not exist. */
1014 {
1015 tree t;
1020 {
1025 }
1027 /* Check for invalid specialization after instantiation:
1029 template <> template <> class C<int>::D<int>;
1030 template <> template <class U> class C<int>::D; */
1034 {
1038 {
1039 /* We already have a full specialization of this partial
1040 instantiation, or a full specialization has been
1041 looked up but not instantiated. Reassign it to the
1042 new member specialization template. */
1043 spec_entry elt;
1055 spec_entry **slot
1060 }
1061 else
1062 /* But if we've had an implicit instantiation, that's a
1063 problem ([temp.expl.spec]/6). */
1066 }
1068 /* Mark TYPE as a specialization. And as a result, we only
1069 have one level of template argument for the innermost
1070 class template. */
1075 }
1076 }
1078 {
1079 /* Someday C++0x may allow for enum template specialization. */
1084 else
1085 {
1088 }
1089 }
1092 }
1094 /* Returns nonzero if we can optimize the retrieval of specializations
1095 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1096 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1100 {
1103 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1104 parameter. */
1106 /* The optimized lookup depends on the fact that the
1107 template arguments for the member function template apply
1108 purely to the containing class, which is not true if the
1109 containing class is an explicit or partial
1110 specialization. */
1114 /* It is possible to have a template that is not a member
1115 template and is not a member of a template class:
1117 template <typename T>
1118 struct S { friend A::f(); };
1120 Here, the friend function is a template, but the context does
1121 not have template information. The optimized lookup relies
1122 on having ARGS be the template arguments for both the class
1123 and the function template. */
1125 }
1127 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1128 gone through coerce_template_parms by now. */
1130 static void
1132 {
1135 {
1138 {
1145 /* Allow typedefs on the type of a non-type argument, since a
1147 else
1149 }
1150 }
1152 }
1154 /* Retrieve the specialization (in the sense of [temp.spec] - a
1155 specialization is either an instantiation or an explicit
1156 specialization) of TMPL for the given template ARGS. If there is
1157 no such specialization, return NULL_TREE. The ARGS are a vector of
1158 arguments, or a vector of vectors of arguments, in the case of
1159 templates with more than one level of parameters.
1161 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1162 then we search for a partial specialization matching ARGS. This
1163 parameter is ignored if TMPL is not a class template.
1165 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1166 result is a NONTYPE_ARGUMENT_PACK. */
1168 static tree
1170 {
1180 /* There should be as many levels of arguments as there are
1181 levels of parameters. */
1191 {
1192 tree class_template;
1193 tree class_specialization;
1195 tree fns;
1198 /* The template arguments actually apply to the containing
1199 class. Find the class specialization with those
1200 arguments. */
1202 class_specialization
1206 /* Now, find the appropriate entry in the CLASSTYPE_METHOD_VEC
1207 for the specialization. */
1211 /* Iterate through the methods with the indicated name, looking
1212 for the one that has an instance of TMPL. */
1215 {
1218 /* using-declarations can add base methods to the method vec,
1219 and we don't want those here. */
1222 }
1224 }
1225 else
1226 {
1228 spec_entry elt;
1237 else
1245 }
1248 }
1250 /* Like retrieve_specialization, but for local declarations. */
1252 tree
1254 {
1260 }
1262 /* Returns nonzero iff DECL is a specialization of TMPL. */
1264 int
1266 {
1267 tree t;
1270 {
1276 }
1277 else
1278 {
1287 }
1290 }
1292 /* Returns nonzero iff DECL is a specialization of friend declaration
1293 FRIEND_DECL according to [temp.friend]. */
1295 bool
1297 {
1304 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1305 of a template class, we want to check if DECL is a specialization
1306 if this. */
1310 {
1311 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1314 }
1319 /* There is nothing to do if this is not a template friend. */
1326 /* [temp.friend/6]
1327 A member of a class template may be declared to be a friend of a
1328 non-template class. In this case, the corresponding member of
1329 every specialization of the class template is a friend of the
1330 class granting friendship.
1332 For example, given a template friend declaration
1334 template <class T> friend void A<T>::f();
1336 the member function below is considered a friend
1338 template <> struct A<int> {
1339 void f();
1340 };
1342 For this type of template friend, TEMPLATE_DEPTH below will be
1343 nonzero. To determine if DECL is a friend of FRIEND, we first
1344 check if the enclosing class is a specialization of another. */
1351 {
1352 /* Next, we check the members themselves. In order to handle
1353 a few tricky cases, such as when FRIEND_DECL's are
1355 template <class T> friend void A<T>::g(T t);
1356 template <class T> template <T t> friend void A<T>::h();
1358 and DECL's are
1360 void A<int>::g(int);
1361 template <int> void A<int>::h();
1363 we need to figure out ARGS, the template arguments from
1364 the context of DECL. This is required for template substitution
1365 of `T' in the function parameter of `g' and template parameter
1366 of `h' in the above examples. Here ARGS corresponds to `int'. */
1373 {
1375 {
1378 else
1380 current_depth++;
1381 }
1383 }
1386 {
1388 tree friend_type;
1389 tree decl_type;
1390 tree friend_args_type;
1391 tree decl_args_type;
1393 /* Make sure that both DECL and FRIEND_DECL are templates or
1394 non-templates. */
1400 {
1401 /* If both are templates, check template parameter list. */
1402 tree friend_parms
1407 friend_parms))
1411 }
1412 else
1420 /* Check if return types match. */
1424 /* Check if function parameter types match, ignoring the
1425 `this' parameter. */
1434 }
1435 else
1436 {
1437 /* DECL is a TYPE_DECL */
1441 /* Make sure that both DECL and FRIEND_DECL are templates or
1442 non-templates. */
1443 is_template
1450 {
1451 tree friend_parms;
1452 /* If both are templates, check the name of the two
1453 TEMPLATE_DECL's first because is_friend didn't. */
1458 /* Now check template parameter list. */
1459 friend_parms
1462 return comp_template_parms
1464 friend_parms);
1465 }
1466 else
1469 }
1470 }
1472 }
1474 /* Register the specialization SPEC as a specialization of TMPL with
1475 the indicated ARGS. IS_FRIEND indicates whether the specialization
1476 is actually just a friend declaration. Returns SPEC, or an
1477 equivalent prior declaration, if available.
1479 We also store instantiations of field packs in the hash table, even
1480 though they are not themselves templates, to make lookup easier. */
1482 static tree
1484 hashval_t hash)
1485 {
1486 tree fn;
1488 spec_entry elt;
1496 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1497 register it; we want the corresponding TEMPLATE_DECL instead.
1498 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1499 the more obvious `uses_template_parms (spec)' to avoid problems
1500 with default function arguments. In particular, given
1501 something like this:
1503 template <class T> void f(T t1, T t = T())
1505 the default argument expression is not substituted for in an
1506 instantiation unless and until it is actually needed. */
1510 /* We don't put these specializations in the hash table, but we might
1511 want to give an error about a mismatch. */
1513 else
1514 {
1522 slot =
1526 else
1528 }
1530 /* We can sometimes try to re-register a specialization that we've
1531 already got. In particular, regenerate_decl_from_template calls
1532 duplicate_decls which will update the specialization list. But,
1533 we'll still get called again here anyhow. It's more convenient
1534 to simply allow this than to try to prevent it. */
1538 {
1540 {
1543 {
1545 fn);
1547 }
1548 else
1549 {
1550 tree clone;
1551 /* This situation should occur only if the first
1552 specialization is an implicit instantiation, the
1553 second is an explicit specialization, and the
1554 implicit instantiation has not yet been used. That
1555 situation can occur if we have implicitly
1556 instantiated a member function and then specialized
1557 it later.
1559 We can also wind up here if a friend declaration that
1560 looked like an instantiation turns out to be a
1561 specialization:
1563 template <class T> void foo(T);
1564 class S { friend void foo<>(int) };
1565 template <> void foo(int);
1567 We transform the existing DECL in place so that any
1568 pointers to it become pointers to the updated
1569 declaration.
1571 If there was a definition for the template, but not
1572 for the specialization, we want this to look as if
1573 there were no definition, and vice versa. */
1576 /* The call to duplicate_decls will have applied
1577 [temp.expl.spec]:
1579 An explicit specialization of a function template
1580 is inline only if it is explicitly declared to be,
1581 and independently of whether its function template
1582 is.
1584 to the primary function; now copy the inline bits to
1585 the various clones. */
1587 {
1594 }
1598 }
1599 }
1601 {
1603 /* Dup decl failed, but this is a new definition. Set the
1604 line number so any errors match this new
1605 definition. */
1609 }
1610 }
1614 /* A specialization must be declared in the same namespace as the
1615 template it is specializing. */
1621 {
1630 /* If TMPL is a forward declaration of a template function, keep a list
1631 of all specializations in case we need to reassign them to a friend
1632 template later in tsubst_friend_function.
1634 Also keep a list of all variable template instantiations so that
1635 process_partial_specialization can check whether a later partial
1636 specialization would have used it. */
1639 }
1642 }
1644 /* Returns true iff two spec_entry nodes are equivalent. */
1648 bool
1650 {
1657 /* tmpl could be a FIELD_DECL for a capture pack. */
1661 {
1662 /* Partial specializations of a variable template can be distinguished by
1663 constraints. */
1667 }
1671 }
1673 /* Returns a hash for a template TMPL and template arguments ARGS. */
1675 static hashval_t
1677 {
1680 }
1682 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1683 ignoring SPEC. */
1685 hashval_t
1687 {
1689 }
1691 /* Recursively calculate a hash value for a template argument ARG, for use
1692 in the hash tables of template specializations. */
1694 hashval_t
1696 {
1716 {
1724 {
1729 }
1751 {
1755 {
1758 }
1760 }
1764 {
1767 }
1778 val = iterative_hash_template_arg
1790 val);
1792 val);
1801 /* A lambda can't appear in a template arg, but don't crash on
1802 erroneous input. */
1814 /* Now hash operands as usual. */
1819 }
1822 {
1825 {
1826 // We want an alias specialization that survived strip_typedefs
1827 // to hash differently from its TYPE_CANONICAL, to avoid hash
1828 // collisions that compare as different in template_args_equal.
1829 // These could be dependent specializations that strip_typedefs
1830 // left alone, or untouched specializations because
1831 // coerce_template_parms returns the unconverted template
1832 // arguments if it sees incomplete argument packs.
1835 }
1838 val);
1841 /* Otherwise just compare the types during lookup. */
1850 {
1855 }
1856 }
1859 }
1861 /* Unregister the specialization SPEC as a specialization of TMPL.
1862 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1863 if the SPEC was listed as a specialization of TMPL.
1865 Note that SPEC has been ggc_freed, so we can't look inside it. */
1867 bool
1869 {
1871 spec_entry elt;
1879 {
1884 }
1887 }
1889 /* Like register_specialization, but for local declarations. We are
1890 registering SPEC, an instantiation of TMPL. */
1892 void
1894 {
1896 }
1898 /* TYPE is a class type. Returns true if TYPE is an explicitly
1899 specialized class. */
1901 bool
1903 {
1907 }
1909 /* Print the list of functions at FNS, going through all the overloads
1910 for each element of the list. Alternatively, FNS can not be a
1911 TREE_LIST, in which case it will be printed together with all the
1912 overloads.
1914 MORE and *STR should respectively be FALSE and NULL when the function
1915 is called from the outside. They are used internally on recursive
1916 calls. print_candidates manages the two parameters and leaves NULL
1917 in *STR when it ends. */
1919 static void
1921 {
1927 {
1931 }
1932 else
1933 {
1936 {
1937 /* Pick the prefix string. */
1939 {
1943 }
1947 }
1950 }
1953 {
1956 }
1957 }
1959 /* Print the list of candidate FNS in an error message. FNS can also
1960 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1962 void
1964 {
1968 }
1970 /* Get a (possibly) constrained template declaration for the
1971 purpose of ordering candidates. */
1972 static tree
1974 {
1980 }
1982 /* Among candidates having the same signature, return the
1983 most constrained or NULL_TREE if there is no best candidate.
1984 If the signatures of candidates vary (e.g., template
1985 specialization vs. member function), then there can be no
1986 most constrained.
1988 Note that we don't compare constraints on the functions
1989 themselves, but rather those of their templates. */
1990 static tree
1992 {
1993 // Try to find the best candidate in a first pass.
1996 {
2003 }
2005 // Verify that the champ is better than previous candidates.
2010 }
2013 }
2016 /* Returns the template (one of the functions given by TEMPLATE_ID)
2017 which can be specialized to match the indicated DECL with the
2018 explicit template args given in TEMPLATE_ID. The DECL may be
2019 NULL_TREE if none is available. In that case, the functions in
2020 TEMPLATE_ID are non-members.
2022 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2023 specialization of a member template.
2025 The TEMPLATE_COUNT is the number of references to qualifying
2026 template classes that appeared in the name of the function. See
2027 check_explicit_specialization for a more accurate description.
2029 TSK indicates what kind of template declaration (if any) is being
2030 declared. TSK_TEMPLATE indicates that the declaration given by
2031 DECL, though a FUNCTION_DECL, has template parameters, and is
2032 therefore a template function.
2034 The template args (those explicitly specified and those deduced)
2035 are output in a newly created vector *TARGS_OUT.
2037 If it is impossible to determine the result, an error message is
2038 issued. The error_mark_node is returned to indicate failure. */
2040 static tree
2042 tree decl,
2046 tmpl_spec_kind tsk)
2047 {
2048 tree fns;
2049 tree targs;
2050 tree explicit_targs;
2053 /* A TREE_LIST of templates of which DECL may be a specialization.
2054 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2055 corresponding TREE_PURPOSE is the set of template arguments that,
2056 when used to instantiate the template, would produce a function
2057 with the signature of DECL. */
2067 /* We shouldn't be specializing a member template of an
2068 unspecialized class template; we already gave an error in
2069 check_specialization_scope, now avoid crashing. */
2072 {
2075 }
2083 /* Check for baselinks. */
2088 {
2091 }
2093 {
2096 }
2098 /* Count the number of template headers specified for this
2099 specialization. */
2109 {
2112 tf_warning_or_error,
2116 }
2118 {
2122 {
2123 tree decl_arg_types;
2124 tree fn_arg_types;
2125 tree insttype;
2127 /* In case of explicit specialization, we need to check if
2128 the number of template headers appearing in the specialization
2129 is correct. This is usually done in check_explicit_specialization,
2130 but the check done there cannot be exhaustive when specializing
2131 member functions. Consider the following code:
2133 template <> void A<int>::f(int);
2134 template <> template <> void A<int>::f(int);
2136 Assuming that A<int> is not itself an explicit specialization
2137 already, the first line specializes "f" which is a non-template
2138 member function, whilst the second line specializes "f" which
2139 is a template member function. So both lines are syntactically
2140 correct, and check_explicit_specialization does not reject
2141 them.
2143 Here, we can do better, as we are matching the specialization
2144 against the declarations. We count the number of template
2145 headers, and we check if they match TEMPLATE_COUNT + 1
2146 (TEMPLATE_COUNT is the number of qualifying template classes,
2147 plus there must be another header for the member template
2148 itself).
2150 Notice that if header_count is zero, this is not a
2151 specialization but rather a template instantiation, so there
2152 is no check we can perform here. */
2156 /* Check that the number of template arguments at the
2157 innermost level for DECL is the same as for FN. */
2165 /* DECL might be a specialization of FN. */
2169 /* For a non-static member function, we need to make sure
2170 that the const qualification is the same. Since
2171 get_bindings does not try to merge the "this" parameter,
2172 we must do the comparison explicitly. */
2178 /* Skip the "this" parameter and, for constructors of
2179 classes with virtual bases, the VTT parameter. A
2180 full specialization of a constructor will have a VTT
2181 parameter, but a template never will. */
2182 decl_arg_types
2184 fn_arg_types
2187 /* Function templates cannot be specializations; there are
2188 no partial specializations of functions. Therefore, if
2189 the type of DECL does not match FN, there is no
2190 match.
2192 Note that it should never be the case that we have both
2193 candidates added here, and for regular member functions
2194 below. */
2196 {
2200 }
2202 /* See whether this function might be a specialization of this
2203 template. Suppress access control because we might be trying
2204 to make this specialization a friend, and we have already done
2205 access control for the declaration of the specialization. */
2211 /* We cannot deduce template arguments that when used to
2212 specialize TMPL will produce DECL. */
2215 /* Remove, from the set of candidates, all those functions
2216 whose constraints are not satisfied. */
2220 // Then, try to form the new function type.
2224 fn_arg_types
2229 /* Save this template, and the arguments deduced. */
2231 }
2233 /* FN is an ordinary member function, and we need a
2234 specialization of a member template. */
2235 ;
2237 /* We can get IDENTIFIER_NODEs here in certain erroneous
2238 cases. */
2239 ;
2241 /* This is just an ordinary non-member function. Nothing can
2242 be a specialization of that. */
2243 ;
2245 /* Cannot specialize functions that are created implicitly. */
2246 ;
2247 else
2248 {
2249 tree decl_arg_types;
2251 /* This is an ordinary member function. However, since
2252 we're here, we can assume its enclosing class is a
2253 template class. For example,
2255 template <typename T> struct S { void f(); };
2256 template <> void S<int>::f() {}
2258 Here, S<int>::f is a non-template, but S<int> is a
2259 template class. If FN has the same type as DECL, we
2260 might be in business. */
2263 /* Its enclosing class is an explicit specialization
2264 of a template class. This is not a candidate. */
2269 /* The return types differ. */
2272 /* Adjust the type of DECL in case FN is a static member. */
2279 decl_arg_types))
2282 // If the deduced arguments do not satisfy the constraints,
2283 // this is not a candidate.
2287 // Add the candidate.
2289 }
2290 }
2293 {
2294 /* We have:
2296 [temp.expl.spec]
2298 It is possible for a specialization with a given function
2299 signature to be instantiated from more than one function
2300 template. In such cases, explicit specification of the
2301 template arguments must be used to uniquely identify the
2302 function template specialization being specialized.
2304 Note that here, there's no suggestion that we're supposed to
2305 determine which of the candidate templates is most
2306 specialized. However, we, also have:
2308 [temp.func.order]
2310 Partial ordering of overloaded function template
2311 declarations is used in the following contexts to select
2312 the function template to which a function template
2313 specialization refers:
2315 -- when an explicit specialization refers to a function
2316 template.
2318 So, we do use the partial ordering rules, at least for now.
2319 This extension can only serve to make invalid programs valid,
2320 so it's safe. And, there is strong anecdotal evidence that
2321 the committee intended the partial ordering rules to apply;
2322 the EDG front end has that behavior, and John Spicer claims
2323 that the committee simply forgot to delete the wording in
2324 [temp.expl.spec]. */
2327 {
2330 }
2331 }
2333 // Concepts allows multiple declarations of member functions
2334 // with the same signature. Like above, we need to rely on
2335 // on the partial ordering of those candidates to determine which
2336 // is the best.
2338 {
2340 {
2343 }
2344 }
2347 {
2354 else
2357 }
2361 {
2367 }
2369 /* We have one, and exactly one, match. */
2371 {
2375 // Propagate the candidate's constraints to the declaration.
2378 /* DECL is a re-declaration or partial instantiation of a template
2379 function. */
2382 /* It was a specialization of an ordinary member function in a
2383 template class. */
2385 }
2387 /* It was a specialization of a template. */
2390 {
2395 }
2396 else
2399 }
2401 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2402 but with the default argument values filled in from those in the
2403 TMPL_TYPES. */
2405 static tree
2407 tree tmpl_types)
2408 {
2409 tree new_spec_types;
2417 /* Substitute into the rest of the list. */
2418 new_spec_types =
2422 /* Add the default argument for this parameter. */
2425 new_spec_types);
2426 }
2428 /* DECL is an explicit specialization. Replicate default arguments
2429 from the template it specializes. (That way, code like:
2431 template <class T> void f(T = 3);
2432 template <> void f(double);
2433 void g () { f (); }
2435 works, as required.) An alternative approach would be to look up
2436 the correct default arguments at the call-site, but this approach
2437 is consistent with how implicit instantiations are handled. */
2439 static void
2441 {
2442 tree tmpl;
2443 tree spec_types;
2444 tree tmpl_types;
2445 tree new_spec_types;
2446 tree old_type;
2447 tree new_type;
2448 tree t;
2453 /* See if there's anything we need to do. */
2466 {
2467 /* Remove the this pointer, but remember the object's type for
2468 CV quals. */
2474 {
2475 /* DECL may contain more parameters than TMPL due to the extra
2476 in-charge parameter in constructors and destructors. */
2479 }
2481 {
2484 }
2485 }
2487 /* Compute the merged default arguments. */
2488 new_spec_types =
2491 /* Compute the new FUNCTION_TYPE. */
2493 {
2497 new_spec_types);
2500 /* Put the in-charge parameter back. */
2503 new_spec_types);
2507 new_spec_types);
2508 }
2509 else
2511 new_spec_types);
2521 }
2523 /* Return the number of template headers we expect to see for a definition
2524 or specialization of CTYPE or one of its non-template members. */
2526 int
2528 {
2532 {
2533 /* You're supposed to have one `template <...>' for every
2534 template class, but you don't need one for a full
2535 specialization. For example:
2537 template <class T> struct S{};
2538 template <> struct S<int> { void f(); };
2539 void S<int>::f () {}
2541 is correct; there shouldn't be a `template <>' for the
2542 definition of `S<int>::f'. */
2544 /* If CTYPE does not have template information of any
2545 kind, then it is not a template, nor is it nested
2546 within a template. */
2554 }
2557 }
2559 /* Do a simple sanity check on the template headers that precede the
2560 variable declaration DECL. */
2562 void
2564 {
2569 {
2572 "variable templates only available with "
2575 // Namespace-scope variable templates should have a template header.
2577 }
2579 {
2586 "members of an explicitly specialized class are defined "
2588 }
2589 }
2591 /* An explicit specialization whose declarator-id or class-head-name is not
2592 qualified shall be declared in the nearest enclosing namespace of the
2593 template, or, if the namespace is inline (7.3.1), any namespace from its
2594 enclosing namespace set.
2596 If the name declared in the explicit instantiation is an unqualified name,
2597 the explicit instantiation shall appear in the namespace where its template
2598 is declared or, if that namespace is inline (7.3.1), any namespace from its
2599 enclosing namespace set. */
2601 void
2603 {
2608 {
2614 /* This was allowed in C++98, so only pedwarn. */
2616 "outside its namespace must use a nested-name-"
2618 }
2619 }
2621 /* Check to see if the function just declared, as indicated in
2622 DECLARATOR, and in DECL, is a specialization of a function
2623 template. We may also discover that the declaration is an explicit
2624 instantiation at this point.
2626 Returns DECL, or an equivalent declaration that should be used
2627 instead if all goes well. Issues an error message if something is
2628 amiss. Returns error_mark_node if the error is not easily
2629 recoverable.
2631 FLAGS is a bitmask consisting of the following flags:
2633 2: The function has a definition.
2634 4: The function is a friend.
2636 The TEMPLATE_COUNT is the number of references to qualifying
2637 template classes that appeared in the name of the function. For
2638 example, in
2640 template <class T> struct S { void f(); };
2641 void S<int>::f();
2643 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2644 classes are not counted in the TEMPLATE_COUNT, so that in
2646 template <class T> struct S {};
2647 template <> struct S<int> { void f(); }
2648 template <> void S<int>::f();
2650 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2651 invalid; there should be no template <>.)
2653 If the function is a specialization, it is marked as such via
2654 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2655 is set up correctly, and it is added to the list of specializations
2656 for that template. */
2658 tree
2660 tree decl,
2663 {
2672 tmpl_spec_kind tsk;
2675 {
2678 else
2680 }
2681 else
2685 {
2688 {
2691 }
2693 {
2695 /* This could be something like:
2697 template <class T> void f(T);
2698 class S { friend void f<>(int); } */
2700 else
2701 {
2702 /* This case handles bogus declarations like template <>
2703 template <class T> void f<int>(); */
2706 declarator);
2708 }
2709 }
2713 /* The error has already been reported in
2714 check_specialization_scope. */
2720 /* Fall through. */
2733 decl);
2736 else
2740 /* Fall through. */
2746 /* In cases like template<> constexpr bool v = true;
2747 We'll give an error in check_template_variable. */
2753 else
2759 {
2760 /* This case handles bogus declarations like template <>
2761 template <class T> void f<int>(); */
2765 declarator);
2767 {
2768 /* Partial specialization of variable template. */
2772 }
2776 else
2780 ok:;
2781 }
2784 /* This is a specialization of a member template, without
2785 specialization the containing class. Something like:
2787 template <class T> struct S {
2788 template <class U> void f (U);
2789 };
2790 template <> template <class U> void S<int>::f(U) {}
2792 That's a specialization -- but of the entire template. */
2798 }
2801 /* This doesn't apply to variable templates. */
2804 {
2808 {
2812 }
2813 }
2816 {
2821 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2823 {
2824 tree fns;
2829 else
2830 {
2831 /* If there is no class context, the explicit instantiation
2832 must be at namespace scope. */
2835 /* Find the namespace binding, using the declaration
2836 context. */
2840 /* If lookup fails, look for a friend declaration so we can
2841 give a better diagnostic. */
2847 {
2850 }
2851 }
2854 }
2860 {
2862 /* A specialization in class scope. This is invalid,
2863 but the error will already have been flagged by
2864 check_specialization_scope. */
2866 else
2867 {
2868 /* It's not valid to write an explicit instantiation in
2869 class scope, e.g.:
2871 class C { template void f(); }
2873 This case is caught by the parser. However, on
2874 something like:
2876 template class C { void f(); };
2878 (which is invalid) we can get here. The error will be
2879 issued later. */
2880 ;
2881 }
2884 }
2887 {
2888 // We'll match variable templates in start_decl.
2892 /* Find the list of functions in ctype that have the same
2893 name as the declared function. */
2899 {
2904 {
2905 /* From [temp.expl.spec]:
2907 If such an explicit specialization for the member
2908 of a class template names an implicitly-declared
2909 special member function (clause _special_), the
2910 program is ill-formed.
2912 Similar language is found in [temp.explicit]. */
2915 }
2918 }
2921 {
2925 }
2926 else
2927 {
2929 tree ovl;
2931 /* For a type-conversion operator, we cannot do a
2932 name-based lookup. We might be looking for `operator
2933 int' which will be a specialization of `operator T'.
2934 So, we find *all* the conversion operators, and then
2935 select from them. */
2943 {
2945 /* There are no more conversion functions. */
2948 /* Glue all these conversion functions together
2949 with those we already have. */
2952 }
2953 }
2956 {
2959 }
2960 else
2962 }
2964 /* Figure out what exactly is being specialized at this point.
2965 Note that for an explicit instantiation, even one for a
2966 member function, we cannot tell apriori whether the
2967 instantiation is for a member template, or just a member
2968 function of a template class. Even if a member template is
2969 being instantiated, the member template arguments may be
2970 elided if they can be deduced from the rest of the
2971 declaration. */
2974 member_specialization,
2975 template_count,
2976 tsk);
2979 /* We couldn't figure out what this declaration was
2980 specializing. */
2982 else
2983 {
2986 {
2988 "friend declaration %qD is not visible to "
2992 }
3000 {
3001 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3002 is done by do_decl_instantiation later. */
3008 {
3009 /* If TMPL is not the most general template (for
3010 example, if TMPL is a friend template that is
3011 injected into namespace scope), then there will
3012 be too many levels of TARGS. Remove some of them
3013 here. */
3015 tree new_targs;
3022 }
3025 }
3027 /* If we thought that the DECL was a member function, but it
3028 turns out to be specializing a static member function,
3029 make DECL a static member function as well. */
3035 /* If this is a specialization of a member template of a
3036 template class, we want to return the TEMPLATE_DECL, not
3037 the specialization of it. */
3039 {
3044 {
3045 tree parm;
3049 /* We want to use the argument list specified in the
3050 definition, not in the original declaration. */
3055 }
3058 }
3060 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3066 /* Inherit default function arguments from the template
3067 DECL is specializing. */
3071 /* This specialization has the same protection as the
3072 template it specializes. */
3076 /* 7.1.1-1 [dcl.stc]
3078 A storage-class-specifier shall not be specified in an
3079 explicit specialization...
3081 The parser rejects these, so unless action is taken here,
3082 explicit function specializations will always appear with
3083 global linkage.
3085 The action recommended by the C++ CWG in response to C++
3086 defect report 605 is to make the storage class and linkage
3087 of the explicit specialization match the templated function:
3089 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3090 */
3092 {
3096 /* A concept cannot be specialized. */
3098 {
3100 gen_tmpl);
3102 }
3104 /* This specialization has the same linkage and visibility as
3105 the function template it specializes. */
3108 {
3111 }
3114 {
3117 }
3118 }
3120 /* If DECL is a friend declaration, declared using an
3121 unqualified name, the namespace associated with DECL may
3122 have been set incorrectly. For example, in:
3124 template <typename T> void f(T);
3125 namespace N {
3126 struct S { friend void f<int>(int); }
3127 }
3129 we will have set the DECL_CONTEXT for the friend
3130 declaration to N, rather than to the global namespace. */
3135 /* This is not really a declaration of a specialization.
3136 It's just the name of an instantiation. But, it's not
3137 a request for an instantiation, either. */
3140 /* A specialization is not necessarily COMDAT. */
3146 /* If this is a full specialization, register it so that we can find
3147 it again. Partial specializations will be registered in
3148 process_partial_specialization. */
3153 /* A 'structor should already have clones. */
3159 }
3160 }
3163 }
3165 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3166 parameters. These are represented in the same format used for
3167 DECL_TEMPLATE_PARMS. */
3169 int
3171 {
3172 const_tree p1;
3173 const_tree p2;
3181 {
3193 {
3197 /* If either of the template parameters are invalid, assume
3198 they match for the sake of error recovery. */
3211 }
3212 }
3215 /* One set of parameters has more parameters lists than the
3216 other. */
3220 }
3222 /* Determine whether PARM is a parameter pack. */
3224 bool
3226 {
3227 /* Determine if we have a non-type template parameter pack. */
3234 /* If this is a list of template parameters, we could get a
3235 TYPE_DECL or a TEMPLATE_DECL. */
3239 /* Otherwise it must be a type template parameter. */
3243 }
3245 /* Determine if T is a function parameter pack. */
3247 bool
3249 {
3253 }
3255 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3256 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3258 tree
3260 {
3267 }
3269 /* Return true iff the function parameter PARAM_DECL was expanded
3270 from the function parameter pack PACK. */
3272 bool
3274 {
3279 /* The parameter pack and its pack arguments have the same
3280 DECL_PARM_INDEX. */
3282 }
3284 /* Determine whether ARGS describes a variadic template args list,
3285 i.e., one that is terminated by a template argument pack. */
3287 static bool
3289 {
3291 tree last_parm;
3305 }
3307 /* Generate a new name for the parameter pack name NAME (an
3308 IDENTIFIER_NODE) that incorporates its */
3310 static tree
3312 {
3313 /* Munge the name to include the parameter index. */
3314 #define NUMBUF_LEN 128
3328 }
3330 /* Return true if T is a primary function, class or alias template
3331 instantiation. */
3333 bool
3335 {
3349 }
3351 /* Return true if PARM is a template template parameter. */
3353 bool
3355 {
3357 }
3359 /* Return true iff PARM is a DECL representing a type template
3360 parameter. */
3362 bool
3364 {
3369 }
3371 /* Return the template parameters of T if T is a
3372 primary template instantiation, NULL otherwise. */
3374 tree
3376 {
3381 parms = INNERMOST_TEMPLATE_PARMS
3385 }
3387 /* Return the template parameters of the LEVELth level from the full list
3388 of template parameters PARMS. */
3390 tree
3392 {
3393 tree p;
3404 }
3406 /* Returns the template arguments of T if T is a template instantiation,
3407 NULL otherwise. */
3409 tree
3411 {
3419 }
3421 /* Return the argument pack elements of T if T is a template argument pack,
3422 NULL otherwise. */
3424 tree
3426 {
3432 }
3434 /* Structure used to track the progress of find_parameter_packs_r. */
3435 struct find_parameter_pack_data
3436 {
3437 /* TREE_LIST that will contain all of the parameter packs found by
3438 the traversal. */
3441 /* Set of AST nodes that have been visited by the traversal. */
3444 /* True iff we're making a type pack expansion. */
3446 };
3448 /* Identifies all of the argument packs that occur in a template
3449 argument and appends them to the TREE_LIST inside DATA, which is a
3450 find_parameter_pack_data structure. This is a subroutine of
3451 make_pack_expansion and uses_parameter_packs. */
3452 static tree
3454 {
3460 /* Handle type aliases/typedefs. */
3462 {
3469 }
3471 /* Identify whether this is a parameter pack or not. */
3473 {
3481 /* FALLTHRU */
3483 /* If the placeholder appears in the decl-specifier-seq of a function
3484 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3485 is a pack expansion, the invented template parameter is a template
3486 parameter pack. */
3496 {
3497 /* We don't want to walk into the type of a PARM_DECL,
3498 because we don't want to see the type parameter pack. */
3501 }
3504 /* Look through a lambda capture proxy to the field pack. */
3507 {
3513 }
3515 {
3517 find_parameter_packs_r,
3520 }
3527 /* Not a parameter pack. */
3529 }
3532 {
3533 /* Add this parameter pack to the list. */
3535 }
3541 /* This switch statement will return immediately if we don't find a
3542 parameter pack. */
3544 {
3549 /* Check the template itself. */
3552 /* Check the template arguments. */
3568 /* Fall through. */
3613 {
3614 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3615 type_pack_expansion_p to false so that any placeholders
3616 within the expression don't get marked as parameter packs. */
3624 }
3628 }
3631 }
3633 /* Determines if the expression or type T uses any parameter packs. */
3634 bool
3636 {
3645 }
3647 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3648 representation a base-class initializer into a parameter pack
3649 expansion. If all goes well, the resulting node will be an
3650 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3651 respectively. */
3652 tree
3654 {
3655 tree result;
3664 {
3665 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3666 class initializer. In this case, the TREE_PURPOSE will be a
3667 _TYPE node (representing the base class expansion we're
3668 initializing) and the TREE_VALUE will be a TREE_LIST
3669 containing the initialization arguments.
3671 The resulting expansion looks somewhat different from most
3672 expansions. Rather than returning just one _EXPANSION, we
3673 return a TREE_LIST whose TREE_PURPOSE is a
3674 TYPE_PACK_EXPANSION containing the bases that will be
3675 initialized. The TREE_VALUE will be identical to the
3676 original TREE_VALUE, which is a list of arguments that will
3677 be passed to each base. We do not introduce any new pack
3678 expansion nodes into the TREE_VALUE (although it is possible
3679 that some already exist), because the TREE_PURPOSE and
3680 TREE_VALUE all need to be expanded together with the same
3681 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3682 resulting TREE_PURPOSE will mention the parameter packs in
3683 both the bases and the arguments to the bases. */
3684 tree purpose;
3685 tree value;
3688 /* Determine which parameter packs will be used by the base
3689 class expansion. */
3698 {
3702 }
3705 {
3706 /* Collect the sets of parameter packs used in each of the
3707 initialization arguments. */
3709 {
3710 /* Determine which parameter packs will be expanded in this
3711 argument. */
3714 }
3715 }
3719 /* Create the pack expansion type for the base type. */
3724 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3725 they will rarely be compared to anything. */
3729 }
3734 /* Build the PACK_EXPANSION_* node. */
3735 result = for_types
3740 {
3741 /* Propagate type and const-expression information. */
3744 /* Mark this read now, since the expansion might be length 0. */
3746 }
3747 else
3748 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3749 they will rarely be compared to anything. */
3752 /* Determine which parameter packs will be expanded. */
3759 /* Make sure we found some parameter packs. */
3761 {
3764 else
3767 }
3773 }
3775 /* Checks T for any "bare" parameter packs, which have not yet been
3776 expanded, and issues an error if any are found. This operation can
3777 only be done on full expressions or types (e.g., an expression
3778 statement, "if" condition, etc.), because we could have expressions like:
3780 foo(f(g(h(args)))...)
3782 where "args" is a parameter pack. check_for_bare_parameter_packs
3783 should not be called for the subexpressions args, h(args),
3784 g(h(args)), or f(g(h(args))), because we would produce erroneous
3785 error messages.
3787 Returns TRUE and emits an error if there were bare parameter packs,
3788 returns FALSE otherwise. */
3789 bool
3791 {
3808 {
3812 {
3821 else
3826 else
3830 }
3833 }
3836 }
3838 /* Expand any parameter packs that occur in the template arguments in
3839 ARGS. */
3840 tree
3842 {
3851 /* First, determine if we need to expand anything, and the number of
3852 slots we'll need. */
3854 {
3859 {
3863 else
3865 }
3866 else
3867 {
3869 num_result_args++;
3870 }
3871 }
3873 /* If no expansion is necessary, we're done. */
3877 /* Expand arguments. */
3880 non_default_args_count =
3883 {
3886 {
3893 }
3894 else
3895 {
3898 }
3899 }
3903 }
3905 /* Checks if DECL shadows a template parameter.
3907 [temp.local]: A template-parameter shall not be redeclared within its
3908 scope (including nested scopes).
3910 Emits an error and returns TRUE if the DECL shadows a parameter,
3911 returns FALSE otherwise. */
3913 bool
3915 {
3916 tree olddecl;
3918 /* If we're not in a template, we can't possibly shadow a template
3919 parameter. */
3923 /* Figure out what we're shadowing. */
3928 /* If there's no previous binding for this name, we're not shadowing
3929 anything, let alone a template parameter. */
3933 /* If we're not shadowing a template parameter, we're done. Note
3934 that OLDDECL might be an OVERLOAD (or perhaps even an
3935 ERROR_MARK), so we can't just blithely assume it to be a _DECL
3936 node. */
3940 /* We check for decl != olddecl to avoid bogus errors for using a
3941 name inside a class. We check TPFI to avoid duplicate errors for
3942 inline member templates. */
3948 /* Don't complain about the injected class name, as we've already
3949 complained about the class itself. */
3956 else
3961 }
3963 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
3964 ORIG_LEVEL, DECL, and TYPE. */
3966 static tree
3970 tree decl,
3971 tree type)
3972 {
3983 }
3985 /* Find the canonical type parameter for the given template type
3986 parameter. Returns the canonical type parameter, which may be TYPE
3987 if no such parameter existed. */
3989 static tree
3991 {
3992 tree list;
4006 else
4007 {
4012 }
4013 }
4015 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4016 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4017 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4018 new one is created. */
4020 static tree
4022 tsubst_flags_t complain)
4023 {
4028 {
4047 /* Template template parameters need this. */
4049 {
4056 }
4057 }
4060 }
4062 /* Process information from new template parameter PARM and append it
4063 to the LIST being built. This new parameter is a non-type
4064 parameter iff IS_NON_TYPE is true. This new parameter is a
4065 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4066 is in PARM_LOC. */
4068 tree
4071 {
4080 {
4084 {
4088 else
4090 }
4093 }
4096 {
4102 {
4103 /* [temp.param]
4105 The top-level cv-qualifiers on the template-parameter are
4106 ignored when determining its type. */
4111 && !is_parameter_pack
4112 /* If we're in a nested template parameter list, the template
4113 template parameter could be a parameter pack. */
4115 {
4116 /* This template parameter is not a parameter pack, but it
4117 should be. Complain about "bare" parameter packs. */
4120 /* Recover by calling this a parameter pack. */
4122 }
4123 }
4125 /* A template parameter is not modifiable. */
4134 processing_template_decl,
4139 }
4140 else
4141 {
4142 tree t;
4146 {
4148 /* This is for distinguishing between real templates and template
4149 template parameters */
4153 }
4154 else
4155 {
4157 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4160 }
4167 processing_template_decl,
4171 }
4175 /* Build requirements for the type/template parameter.
4176 This must be done after SET_DECL_TEMPLATE_PARM_P or
4177 process_template_parm could fail. */
4182 /* Build the parameter node linking the parameter declaration,
4183 its default argument (if any), and its constraints (if any). */
4188 }
4190 /* The end of a template parameter list has been reached. Process the
4191 tree list into a parameter vector, converting each parameter into a more
4192 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4193 as PARM_DECLs. */
4195 tree
4197 {
4202 /* Pop the dummy parameter level and add the real one. */
4205 current_template_parms
4210 {
4214 }
4219 }
4221 // Explicitly indicate the end of the template parameter list. We assume
4222 // that the current template parameters have been constructed and/or
4223 // managed explicitly, as when creating new template template parameters
4224 // from a shorthand constraint.
4225 void
4227 {
4229 }
4231 /* end_template_decl is called after a template declaration is seen. */
4233 void
4235 {
4241 /* This matches the pushlevel in begin_template_parm_list. */
4246 }
4248 /* Takes a TREE_LIST representing a template parameter and convert it
4249 into an argument suitable to be passed to the type substitution
4250 functions. Note that If the TREE_LIST contains an error_mark
4251 node, the returned argument is error_mark_node. */
4253 tree
4255 {
4268 {
4272 {
4273 /* Turn this argument into a TYPE_ARGUMENT_PACK
4274 with a single element, which expands T. */
4283 }
4284 }
4285 else
4286 {
4290 {
4291 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4292 with a single element, which expands T. */
4304 }
4305 else
4307 }
4309 }
4311 /* Given a single level of template parameters (a TREE_VEC), return it
4312 as a set of template arguments. */
4314 static tree
4316 {
4326 }
4328 /* Given a set of template parameters, return them as a set of template
4329 arguments. The template parameters are represented as a TREE_VEC, in
4330 the form documented in cp-tree.h for template arguments. */
4332 static tree
4334 {
4335 tree header;
4340 /* If there is only one level of template parameters, we do not
4341 create a TREE_VEC of TREE_VECs. Instead, we return a single
4342 TREE_VEC containing the arguments. */
4347 {
4352 else
4354 }
4357 }
4359 /* Within the declaration of a template, return the currently active
4360 template parameters as an argument TREE_VEC. */
4362 static tree
4364 {
4366 }
4368 /* Update the declared TYPE by doing any lookups which were thought to be
4369 dependent, but are not now that we know the SCOPE of the declarator. */
4371 tree
4373 {
4384 /* Don't bother building up the args in this case. */
4386 {
4387 /* tsubst in the args corresponding to the template parameters,
4388 including auto if present. Most things will be unchanged, but
4389 make_typename_type and tsubst_qualified_id will resolve
4390 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4393 tree pushed;
4395 {
4399 }
4404 }
4410 {
4413 else
4415 }
4417 }
4419 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4420 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4421 the new template is a member template. */
4423 tree
4425 {
4433 }
4435 struct template_parm_data
4436 {
4437 /* The level of the template parameters we are currently
4438 processing. */
4441 /* The index of the specialization argument we are currently
4442 processing. */
4445 /* An array whose size is the number of template parameters. The
4446 elements are nonzero if the parameter has been used in any one
4447 of the arguments processed so far. */
4450 /* An array whose size is the number of template arguments. The
4451 elements are nonzero if the argument makes use of template
4452 parameters of this level. */
4454 };
4456 /* Subroutine of push_template_decl used to see if each template
4457 parameter in a partial specialization is used in the explicit
4458 argument list. If T is of the LEVEL given in DATA (which is
4459 treated as a template_parm_data*), then DATA->PARMS is marked
4460 appropriately. */
4462 static int
4464 {
4472 {
4475 }
4477 /* In C++17 the type of a non-type argument is a deduced context. */
4482 data,
4483 NULL,
4486 /* Return zero so that for_each_template_parm will continue the
4487 traversal of the tree; we want to mark *every* template parm. */
4489 }
4491 /* Process the partial specialization DECL. */
4493 static tree
4495 {
4502 tree inner_parms;
4503 tree inst;
4513 /* A concept cannot be specialized. */
4515 {
4518 }
4523 /* We check that each of the template parameters given in the
4524 partial specialization is used in the argument list to the
4525 specialization. For example:
4527 template <class T> struct S;
4528 template <class T> struct S<T*>;
4530 The second declaration is OK because `T*' uses the template
4531 parameter T, whereas
4533 template <class T> struct S<int>;
4535 is no good. Even trickier is:
4537 template <class T>
4538 struct S1
4539 {
4540 template <class U>
4541 struct S2;
4542 template <class U>
4543 struct S2<T>;
4544 };
4546 The S2<T> declaration is actually invalid; it is a
4547 full-specialization. Of course,
4549 template <class U>
4550 struct S2<T (*)(U)>;
4552 or some such would have been OK. */
4560 {
4565 NULL,
4567 }
4570 {
4571 /* One of the template parms was not used in a deduced context in the
4572 specialization. */
4574 {
4578 }
4582 }
4587 /* [temp.class.spec]
4589 The argument list of the specialization shall not be identical to
4590 the implicit argument list of the primary template. */
4591 tree main_args
4594 && (!flag_concepts
4597 {
4601 else
4605 }
4607 /* A partial specialization that replaces multiple parameters of the
4608 primary template with a pack expansion is less specialized for those
4609 parameters. */
4611 {
4613 "primary template because it replaces multiple parameters "
4616 /* Avoid crash in process_partial_specialization. */
4618 }
4620 /* If we aren't in a dependent class, we can actually try deduction. */
4622 /* FIXME we should be able to handle a partial specialization of a
4623 partial instantiation, but currently we can't (c++/41727). */
4626 {
4630 maintmpl);
4631 }
4633 /* [temp.class.spec]
4635 A partially specialized non-type argument expression shall not
4636 involve template parameters of the partial specialization except
4637 when the argument expression is a simple identifier.
4639 The type of a template parameter corresponding to a specialized
4640 non-type argument shall not be dependent on a parameter of the
4641 specialization.
4643 Also, we verify that pack expansions only occur at the
4644 end of the argument list. */
4648 {
4655 {
4656 /* Extract the arguments from the argument pack. We'll be
4657 iterating over these in the following loop. */
4660 }
4663 {
4665 /* Get the Jth argument in the parameter pack. */
4669 {
4670 /* Pack expansions must come at the end of the
4671 argument list. */
4674 {
4678 else
4681 }
4682 }
4685 /* We only care about the pattern. */
4691 /* This next two lines are the `argument expression is not just a
4692 simple identifier' condition and also the `specialized
4693 non-type argument' bit. */
4697 {
4701 arg);
4702 else
4703 {
4704 /* Look at the corresponding template parameter,
4705 marking which template parameters its type depends
4706 upon. */
4710 {
4711 /* We haven't yet initialized TPD2. Do so now. */
4713 /* The number of parameters here is the number in the
4714 main template, which, as checked in the assertion
4715 above, is NARGS. */
4719 }
4721 /* Mark the template parameters. But this time, we're
4722 looking for the template parameters of the main
4723 template, not in the specialization. */
4730 NULL,
4734 {
4735 /* The type depended on some template parameters.
4736 If they are fully specialized in the
4737 specialization, that's OK. */
4746 "type %qT of template argument %qE depends "
4748 "type %qT of template argument %qE depends "
4750 type,
4751 arg);
4752 }
4753 }
4754 }
4755 }
4756 }
4758 /* We should only get here once. */
4762 // Build the template decl.
4771 /* Give template template parms a DECL_CONTEXT of the template
4772 for which they are a parameter. */
4774 {
4778 }
4781 /* We didn't register this in check_explicit_specialization so we could
4782 wait until the constraints were set. */
4784 else
4794 {
4800 {
4808 "declaration of %qD ambiguates earlier template "
4812 "partial specialization of %qD after instantiation "
4814 }
4815 }
4818 }
4820 /* PARM is a template parameter of some form; return the corresponding
4821 TEMPLATE_PARM_INDEX. */
4823 static tree
4825 {
4838 }
4840 /* Subroutine of fixed_parameter_pack_p below. Look for any template
4841 parameter packs used by the template parameter PARM. */
4843 static void
4845 {
4846 /* A type parm can't refer to another parm. */
4850 {
4854 }
4861 }
4863 /* PARM is a template parameter pack. Return any parameter packs used in
4864 its type or the type of any of its template parameters. If there are
4865 any such packs, it will be instantiated into a fixed template parameter
4866 list by partial instantiation rather than be fully deduced. */
4868 tree
4870 {
4871 /* This can only be true in a member template. */
4874 /* This can only be true for a parameter pack. */
4877 /* A type parm can't refer to another parm. */
4891 }
4893 /* Check that a template declaration's use of default arguments and
4894 parameter packs is not invalid. Here, PARMS are the template
4895 parameters. IS_PRIMARY is true if DECL is the thing declared by
4896 a primary template. IS_PARTIAL is true if DECL is a partial
4897 specialization.
4899 IS_FRIEND_DECL is nonzero if DECL is a friend function template
4900 declaration (but not a definition); 1 indicates a declaration, 2
4901 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4902 emitted for extraneous default arguments.
4904 Returns TRUE if there were no errors found, FALSE otherwise. */
4906 bool
4909 {
4912 tree parm_level;
4915 /* [temp.param]
4917 A default template-argument shall not be specified in a
4918 function template declaration or a function template definition, nor
4919 in the template-parameter-list of the definition of a member of a
4920 class template. */
4924 /* You can't have a function template declaration in a local
4925 scope, nor you can you define a member of a class template in a
4926 local scope. */
4934 /* A lambda doesn't have an explicit declaration; don't complain
4935 about the parms of the enclosing class. */
4942 /* If this is either a friend defined in the scope of the class
4943 or a member function. */
4949 /* And, if it was a member function, it really was defined in
4950 the scope of the class. */
4953 /* We already checked these parameters when the template was
4954 declared, so there's no need to do it again now. This function
4955 was defined in class scope, but we're processing its body now
4956 that the class is complete. */
4959 /* Core issue 226 (C++0x only): the following only applies to class
4960 templates. */
4963 {
4964 /* [temp.param]
4966 If a template-parameter has a default template-argument, all
4967 subsequent template-parameters shall have a default
4968 template-argument supplied. */
4970 {
4977 {
4987 {
4989 /* For better subsequent error-recovery, we indicate that
4990 there should have been a default argument. */
4993 }
4995 && !is_friend_decl
4996 /* Don't complain about an enclosing partial
4997 specialization. */
5002 /* A fixed parameter pack will be partially
5003 instantiated into a fixed length list. */
5005 {
5006 /* A primary class template can only have one
5007 parameter pack, at the end of the template
5008 parameter list. */
5016 }
5017 }
5018 }
5019 }
5022 || is_partial
5023 || !is_primary
5025 /* For an ordinary class template, default template arguments are
5026 allowed at the innermost level, e.g.:
5027 template <class T = int>
5028 struct S {};
5029 but, in a partial specialization, they're not allowed even
5030 there, as we have in [temp.class.spec]:
5032 The template parameter list of a specialization shall not
5033 contain default template argument values.
5035 So, for a partial specialization, or for a function template
5036 (in C++98/C++03), we look at all of them. */
5037 ;
5038 else
5039 /* But, for a primary class template that is not a partial
5040 specialization we look at all template parameters except the
5041 innermost ones. */
5044 /* Figure out what error message to issue. */
5059 else
5060 /* Per [temp.param]/9, "A default template-argument shall not be
5061 specified in the template-parameter-lists of the definition of
5062 a member of a class template that appears outside of the member's
5063 class.", thus if we aren't handling a member of a class template
5064 there is no need to examine the parameters. */
5068 /* If we're inside a class definition, there's no need to
5069 examine the parameters to the class itself. On the one
5070 hand, they will be checked when the class is defined, and,
5071 on the other, default arguments are valid in things like:
5072 template <class T = double>
5073 struct S { template <class U> void f(U); };
5074 Here the default argument for `S' has no bearing on the
5075 declaration of `f'. */
5077 else
5078 /* Check everything. */
5084 {
5091 {
5096 {
5098 {
5105 }
5107 /* Clear out the default argument so that we are not
5108 confused later. */
5110 }
5111 }
5113 /* At this point, if we're still interested in issuing messages,
5114 they must apply to classes surrounding the object declared. */
5118 }
5121 }
5123 /* Worker for push_template_decl_real, called via
5124 for_each_template_parm. DATA is really an int, indicating the
5125 level of the parameters we are interested in. If T is a template
5126 parameter of that level, return nonzero. */
5128 static int
5130 {
5136 else
5139 }
5141 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5142 DATA is really an int, indicating the innermost outer level of parameters.
5143 If T is a template parameter of that level or further out, return
5144 nonzero. */
5146 static int
5148 {
5154 else
5157 }
5159 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5160 parameters given by current_template_args, or reuses a
5161 previously existing one, if appropriate. Returns the DECL, or an
5162 equivalent one, if it is replaced via a call to duplicate_decls.
5164 If IS_FRIEND is true, DECL is a friend declaration. */
5166 tree
5168 {
5169 tree tmpl;
5170 tree args;
5171 tree info;
5172 tree ctx;
5176 /* True if the template is a member template, in the sense of
5177 [temp.mem]. */
5183 /* See if this is a partial specialization. */
5196 /* For a friend, we want the context of the friend function, not
5197 the type of which it is a friend. */
5201 /* In the case of a virtual function, we want the class in which
5202 it is defined. */
5204 else
5205 /* Otherwise, if we're currently defining some class, the DECL
5206 is assumed to be a member of the class. */
5215 /* See if this is a primary template. */
5218 /* A friend template that specifies a class context, i.e.
5219 template <typename T> friend void A<T>::f();
5220 is not primary. */
5225 else
5229 {
5236 {
5239 }
5241 {
5243 {
5246 }
5248 {
5249 /* [temp.mem]
5251 A destructor shall not be a member template. */
5254 }
5261 {
5262 /* [basic.stc.dynamic.allocation]
5264 An allocation function can be a function
5265 template. ... Template allocation functions shall
5266 have two or more parameters. */
5269 }
5270 }
5273 {
5274 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5277 {
5283 }
5284 }
5287 /* alias-declaration */
5291 else
5292 {
5295 }
5296 }
5298 /* Check to see that the rules regarding the use of default
5299 arguments are not being violated. */
5303 /* Ensure that there are no parameter packs in the type of this
5304 declaration that have not been expanded. */
5306 {
5307 /* Check each of the arguments individually to see if there are
5308 any bare parameter packs. */
5314 {
5317 {
5318 /* This is a PARM_DECL that contains unexpanded parameter
5319 packs. We have already complained about this in the
5320 check_for_bare_parameter_packs call, so just replace
5321 these types with ERROR_MARK_NODE. */
5324 }
5328 }
5330 /* Check for bare parameter packs in the return type and the
5331 exception specifiers. */
5333 /* Errors were already issued, set return type to int
5334 as the frontend doesn't expect error_mark_node as
5335 the return type. */
5339 }
5344 {
5347 }
5360 {
5365 /* If DECL is a TYPE_DECL for a class-template, then there won't
5366 be DECL_LANG_SPECIFIC. The information equivalent to
5367 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5371 {
5372 /* Since a template declaration already existed for this
5373 class-type, we must be redeclaring it here. Make sure
5374 that the redeclaration is valid. */
5376 current_template_parms,
5378 /* We don't need to create a new TEMPLATE_DECL; just use the
5379 one we already had. */
5381 }
5382 else
5383 {
5385 member_template_p);
5390 {
5391 /* A specialization of a member template of a template
5392 class. */
5396 }
5397 }
5398 }
5399 else
5400 {
5406 {
5409 }
5417 {
5418 tree new_tmpl;
5420 /* The declaration is a specialization of a member
5421 template, declared outside the class. Therefore, the
5422 innermost template arguments will be NULL, so we
5423 replace them with the arguments determined by the
5424 earlier call to check_explicit_specialization. */
5427 new_tmpl
5429 member_template_p);
5439 args,
5442 }
5444 /* Make sure the template headers we got make sense. */
5449 {
5454 }
5455 else
5457 {
5462 {
5466 else
5470 /* Avoid crash in import_export_decl. */
5473 }
5478 /* Can happen in erroneous input. */
5480 else
5482 }
5484 /* Check that the parms are used in the appropriate qualifying scopes
5485 in the declarator. */
5489 {
5495 /* Avoid crash in import_export_decl. */
5498 }
5499 }
5504 /* Push template declarations for global functions and types. Note
5505 that we do not try to push a global template friend declared in a
5506 template class; such a thing may well depend on the template
5507 parameters of the class. */
5510 {
5515 /* Hide template friend classes that haven't been declared yet. */
5517 {
5520 }
5521 }
5524 {
5530 {
5533 /* It is a conversion operator. See if the type converted to
5534 depends on innermost template operands. */
5537 depth))
5539 }
5541 /* Give template template parms a DECL_CONTEXT of the template
5542 for which they are a parameter. */
5545 {
5549 }
5555 }
5557 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5558 back to its most general template. If TMPL is a specialization,
5559 ARGS may only have the innermost set of arguments. Add the missing
5560 argument levels if necessary. */
5568 else
5569 {
5574 }
5577 && !is_friend
5580 /* Set DECL_COMDAT on template instantiations; if we force
5581 them to be emitted by explicit instantiation or -frepo,
5582 mark_needed will tell cgraph to do the right thing. */
5586 }
5588 tree
5590 {
5592 }
5594 /* FN is an inheriting constructor that inherits from the constructor
5595 template INHERITED; turn FN into a constructor template with a matching
5596 template header. */
5598 tree
5600 {
5601 tree inner_parms
5604 tree parms
5615 }
5617 /* Called when a class template TYPE is redeclared with the indicated
5618 template PARMS, e.g.:
5620 template <class T> struct S;
5621 template <class T> struct S {}; */
5623 bool
5625 {
5626 tree tmpl;
5627 tree tmpl_parms;
5631 {
5634 }
5638 /* The type is nested in some template class. Nothing to worry
5639 about here; there are no new template parameters for the nested
5640 type. */
5644 {
5646 tmpl);
5648 }
5654 {
5664 }
5667 {
5668 tree tmpl_parm;
5669 tree parm;
5670 tree tmpl_default;
5671 tree parm_default;
5685 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5686 TEMPLATE_DECL. */
5696 {
5700 }
5703 {
5704 /* We have in [temp.param]:
5706 A template-parameter may not be given default arguments
5707 by two different declarations in the same scope. */
5712 }
5715 /* Update the previous template parameters (which are the ones
5716 that will really count) with the new default value. */
5719 /* Update the new parameters, too; they'll be used as the
5720 parameters for any members. */
5723 /* Give each template template parm in this redeclaration a
5724 DECL_CONTEXT of the template for which they are a parameter. */
5726 {
5729 }
5730 }
5732 // Cannot redeclare a class template with a different set of constraints.
5734 {
5739 }
5742 }
5744 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5745 to be used when the caller has already checked
5746 (processing_template_decl
5747 && !instantiation_dependent_expression_p (expr)
5748 && potential_constant_expression (expr))
5749 and cleared processing_template_decl. */
5751 tree
5753 {
5756 complain,
5760 }
5762 /* Simplify EXPR if it is a non-dependent expression. Returns the
5763 (possibly simplified) expression. */
5765 tree
5767 {
5771 /* If we're in a template, but EXPR isn't value dependent, simplify
5772 it. We're supposed to treat:
5774 template <typename T> void f(T[1 + 1]);
5775 template <typename T> void f(T[2]);
5777 as two declarations of the same function, for example. */
5780 {
5781 processing_template_decl_sentinel s;
5783 }
5785 }
5787 tree
5789 {
5791 }
5793 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
5794 an uninstantiated expression. */
5796 tree
5798 {
5802 {
5805 else
5806 {
5807 processing_template_decl_sentinel s;
5809 }
5810 }
5812 }
5814 /* True iff T is a specialization of a variable template. */
5816 bool
5818 {
5823 }
5825 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5826 template declaration, or a TYPE_DECL for an alias declaration. */
5828 bool
5830 {
5838 }
5840 /* Return TRUE iff T is a specialization of an alias template. */
5842 bool
5844 {
5845 /* It's an alias template specialization if it's an alias and its
5846 TYPE_NAME is a specialization of a primary template. */
5852 }
5854 /* An alias template is complex from a SFINAE perspective if a template-id
5855 using that alias can be ill-formed when the expansion is not, as with
5856 the void_t template. We determine this by checking whether the
5857 expansion for the alias template uses all its template parameters. */
5859 struct uses_all_template_parms_data
5860 {
5863 };
5865 static int
5867 {
5875 }
5877 static bool
5879 {
5894 }
5896 /* Return TRUE iff T is a specialization of a complex alias template with
5897 dependent template-arguments. */
5899 bool
5901 {
5914 }
5916 /* Return the number of innermost template parameters in TMPL. */
5918 static int
5920 {
5923 }
5925 /* Return either TMPL or another template that it is equivalent to under DR
5926 1286: An alias that just changes the name of a template is equivalent to
5927 the other template. */
5929 static tree
5931 {
5934 {
5935 /* Determine if the alias is equivalent to an underlying template. */
5947 tree alias_args = INNERMOST_TEMPLATE_ARGS
5952 /* Alias is equivalent. Strip it and repeat. */
5954 }
5957 }
5959 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
5960 must be a reference-to-function or a pointer-to-function type, as specified
5961 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
5962 and check that the resulting function has external linkage. */
5964 static tree
5966 tsubst_flags_t complain)
5967 {
5970 linkage_kind linkage;
5985 /* [temp.arg.nontype]/1
5987 A template-argument for a non-type, non-template template-parameter
5988 shall be one of:
5989 [...]
5990 -- the address of an object or function with external [C++11: or
5991 internal] linkage. */
5994 {
5996 {
6002 else
6005 }
6007 }
6011 {
6013 {
6018 else
6022 }
6024 }
6032 }
6034 /* Subroutine of convert_nontype_argument.
6035 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6036 Emit an error otherwise. */
6038 static bool
6040 tsubst_flags_t complain)
6041 {
6052 {
6056 }
6058 }
6060 /* Returns TRUE iff the address of OP is value-dependent.
6062 14.6.2.4 [temp.dep.temp]:
6063 A non-integral non-type template-argument is dependent if its type is
6064 dependent or it has either of the following forms
6065 qualified-id
6066 & qualified-id
6067 and contains a nested-name-specifier which specifies a class-name that
6068 names a dependent type.
6070 We generalize this to just say that the address of a member of a
6071 dependent class is value-dependent; the above doesn't cover the
6072 address of a static data member named with an unqualified-id. */
6074 static bool
6076 {
6077 /* We could use get_inner_reference here, but there's no need;
6078 this is only relevant for template non-type arguments, which
6079 can only be expressed as &id-expression. */
6081 {
6085 }
6088 }
6090 /* The next set of functions are used for providing helpful explanatory
6091 diagnostics for failed overload resolution. Their messages should be
6092 indented by two spaces for consistency with the messages in
6093 call.c */
6095 static int
6097 {
6099 }
6101 static int
6103 {
6108 }
6110 static int
6112 {
6114 }
6116 static int
6118 {
6124 }
6126 static int
6128 {
6132 }
6134 static int
6136 {
6139 " template parameter %qD is not a parameter pack, but "
6143 }
6145 static int
6147 {
6150 " template argument %qE does not match "
6154 }
6156 static int
6158 {
6162 }
6164 static int
6166 {
6172 }
6174 static int
6176 {
6178 {
6183 else
6185 " deduced conflicting values for non-type parameter "
6187 }
6189 }
6191 static int
6193 {
6196 " variable-sized array type %qT is not "
6198 arg);
6200 }
6202 static int
6204 {
6208 arg);
6210 }
6212 static int
6214 {
6216 {
6222 else
6227 }
6229 }
6231 static int
6233 {
6235 }
6237 static int
6240 {
6242 }
6244 static int
6247 {
6253 }
6255 static int
6258 {
6261 {
6269 }
6271 }
6273 static int
6275 {
6278 " template parameters of a template template argument are "
6281 }
6283 static int
6285 {
6291 }
6293 static int
6295 {
6300 }
6302 static int
6304 {
6308 arg);
6310 }
6312 /* Attempt to convert the non-type template parameter EXPR to the
6313 indicated TYPE. If the conversion is successful, return the
6314 converted value. If the conversion is unsuccessful, return
6315 NULL_TREE if we issued an error message, or error_mark_node if we
6316 did not. We issue error messages for out-and-out bad template
6317 parameters, but not simply because the conversion failed, since we
6318 might be just trying to do argument deduction. Both TYPE and EXPR
6319 must be non-dependent.
6321 The conversion follows the special rules described in
6322 [temp.arg.nontype], and it is much more strict than an implicit
6323 conversion.
6325 This function is called twice for each template argument (see
6326 lookup_template_class for a more accurate description of this
6327 problem). This means that we need to handle expressions which
6328 are not valid in a C++ source, but can be created from the
6329 first call (for instance, casts to perform conversions). These
6330 hacks can go away after we fix the double coercion problem. */
6332 static tree
6334 {
6335 tree expr_type;
6337 /* Detect immediately string literals as invalid non-type argument.
6338 This special-case is not needed for correctness (we would easily
6339 catch this later), but only to provide better diagnostic for this
6340 common user mistake. As suggested by DR 100, we do not mention
6341 linkage issues in the diagnostic as this is not the point. */
6342 /* FIXME we're making this OK. */
6344 {
6350 }
6352 /* Add the ADDR_EXPR now for the benefit of
6353 value_dependent_expression_p. */
6356 {
6360 }
6362 /* If we are in a template, EXPR may be non-dependent, but still
6363 have a syntactic, rather than semantic, form. For example, EXPR
6364 might be a SCOPE_REF, rather than the VAR_DECL to which the
6365 SCOPE_REF refers. Preserving the qualifying scope is necessary
6366 so that access checking can be performed when the template is
6367 instantiated -- but here we need the resolved form so that we can
6368 convert the argument. */
6381 else
6384 /* If the argument is non-dependent, perform any conversions in
6385 non-dependent context as well. */
6393 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6394 to a non-type argument of "nullptr". */
6398 /* In C++11, integral or enumeration non-type template arguments can be
6399 arbitrary constant expressions. Pointer and pointer to
6400 member arguments can be general constant expressions that evaluate
6401 to a null value, but otherwise still need to be of a specific form. */
6403 {
6405 /* A PTRMEM_CST is already constant, and a valid template
6406 argument for a parameter of pointer to member type, we just want
6407 to leave it in that form rather than lower it to a
6412 {
6416 {
6420 }
6421 }
6423 {
6428 }
6429 }
6431 /* HACK: Due to double coercion, we can get a
6432 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6433 which is the tree that we built on the first call (see
6434 below when coercing to reference to object or to reference to
6435 function). We just strip everything and get to the arg.
6436 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6437 for examples. */
6439 {
6445 {
6446 /* ??? Maybe we could use convert_from_reference here, but we
6447 would need to relax its constraints because the NOP_EXPR
6448 could actually change the type to something more cv-qualified,
6449 and this is not folded by convert_from_reference. */
6454 && (same_type_ignoring_top_level_qualifiers_p
6457 {
6460 }
6461 }
6462 }
6464 /* We could also generate a NOP_EXPR(ADDR_EXPR()) when the
6465 parameter is a pointer to object, through decay and
6466 qualification conversion. Let's strip everything. */
6468 {
6473 {
6474 /* Skip the ADDR_EXPR only if it is part of the decay for
6475 an array. Otherwise, it is part of the original argument
6476 in the source code. */
6481 }
6482 }
6484 /* [temp.arg.nontype]/5, bullet 1
6486 For a non-type template-parameter of integral or enumeration type,
6487 integral promotions (_conv.prom_) and integral conversions
6488 (_conv.integral_) are applied. */
6490 {
6499 /* Notice that there are constant expressions like '4 % 0' which
6500 do not fold into integer constants. */
6503 {
6505 {
6516 /* else cxx_constant_value complained but gave us
6517 a real constant, so go ahead. */
6519 }
6520 else
6522 }
6524 /* Avoid typedef problems. */
6527 }
6528 /* [temp.arg.nontype]/5, bullet 2
6530 For a non-type template-parameter of type pointer to object,
6531 qualification conversions (_conv.qual_) and the array-to-pointer
6532 conversion (_conv.array_) are applied. */
6534 {
6535 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6537 A template-argument for a non-type, non-template template-parameter
6538 shall be one of: [...]
6540 -- the name of a non-type template-parameter;
6541 -- the address of an object or function with external linkage, [...]
6542 expressed as "& id-expression" where the & is optional if the name
6543 refers to a function or array, or if the corresponding
6544 template-parameter is a reference.
6546 Here, we do not care about functions, as they are invalid anyway
6547 for a parameter of type pointer-to-object. */
6550 /* Non-type template parameters are OK. */
6551 ;
6556 {
6558 {
6561 "because %qD is a variable, not the address of "
6564 }
6566 {
6572 }
6573 /* Other values, like integer constants, might be valid
6574 non-type arguments of some other type. */
6576 }
6577 else
6578 {
6579 tree decl;
6584 {
6589 }
6591 {
6597 }
6599 {
6604 }
6605 }
6614 }
6615 /* [temp.arg.nontype]/5, bullet 3
6617 For a non-type template-parameter of type reference to object, no
6618 conversions apply. The type referred to by the reference may be more
6619 cv-qualified than the (otherwise identical) type of the
6620 template-argument. The template-parameter is bound directly to the
6621 template-argument, which must be an lvalue. */
6623 {
6625 expr_type))
6629 {
6634 }
6637 {
6642 }
6644 /* [temp.arg.nontype]/1
6646 A template-argument for a non-type, non-template template-parameter
6647 shall be one of: [...]
6649 -- the address of an object or function with external linkage. */
6652 {
6655 {
6658 "because a reference variable does not have a constant "
6661 }
6662 }
6665 {
6667 {
6673 }
6675 /* DR 1155 allows internal linkage in C++11 and up. */
6678 {
6684 }
6687 }
6688 }
6689 /* [temp.arg.nontype]/5, bullet 4
6691 For a non-type template-parameter of type pointer to function, only
6692 the function-to-pointer conversion (_conv.func_) is applied. If the
6693 template-argument represents a set of overloaded functions (or a
6694 pointer to such), the matching function is selected from the set
6695 (_over.over_). */
6697 {
6698 /* If the argument is a template-id, we might not have enough
6699 context information to decay the pointer. */
6701 {
6705 }
6708 /* Null pointer values are OK in C++11. */
6714 }
6715 /* [temp.arg.nontype]/5, bullet 5
6717 For a non-type template-parameter of type reference to function, no
6718 conversions apply. If the template-argument represents a set of
6719 overloaded functions, the matching function is selected from the set
6720 (_over.over_). */
6722 {
6724 {
6726 {
6731 }
6733 }
6738 }
6739 /* [temp.arg.nontype]/5, bullet 6
6741 For a non-type template-parameter of type pointer to member function,
6742 no conversions apply. If the template-argument represents a set of
6743 overloaded member functions, the matching member function is selected
6744 from the set (_over.over_). */
6746 {
6751 /* [temp.arg.nontype] bullet 1 says the pointer to member
6752 expression must be a pointer-to-member constant. */
6757 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
6758 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
6762 /* There is no way to disable standard conversions in
6763 resolve_address_of_overloaded_function (called by
6764 instantiate_type). It is possible that the call succeeded by
6765 converting &B::I to &D::I (where B is a base of D), so we need
6766 to reject this conversion here.
6768 Actually, even if there was a way to disable standard conversions,
6769 it would still be better to reject them here so that we can
6770 provide a superior diagnostic. */
6772 {
6774 {
6778 /* If we are just one standard conversion off, explain. */
6782 }
6784 }
6785 }
6786 /* [temp.arg.nontype]/5, bullet 7
6788 For a non-type template-parameter of type pointer to data member,
6789 qualification conversions (_conv.qual_) are applied. */
6791 {
6792 /* [temp.arg.nontype] bullet 1 says the pointer to member
6793 expression must be a pointer-to-member constant. */
6801 }
6803 {
6805 {
6810 }
6812 }
6813 /* A template non-type parameter must be one of the above. */
6814 else
6817 /* Sanity check: did we actually convert the argument to the
6818 right type? */
6822 }
6824 /* Subroutine of coerce_template_template_parms, which returns 1 if
6825 PARM_PARM and ARG_PARM match using the rule for the template
6826 parameters of template template parameters. Both PARM and ARG are
6827 template parameters; the rest of the arguments are the same as for
6828 coerce_template_template_parms.
6829 */
6830 static int
6832 tree arg,
6833 tsubst_flags_t complain,
6834 tree in_decl,
6835 tree outer_args)
6836 {
6845 {
6847 /* We encounter instantiations of templates like
6848 template <template <template <class> class> class TT>
6849 class C; */
6850 {
6857 }
6858 /* Fall through. */
6863 /* Argument is a parameter pack but parameter is not. */
6868 /* The tsubst call is used to handle cases such as
6870 template <int> class C {};
6871 template <class T, template <T> class TT> class D {};
6872 D<int, C> d;
6874 i.e. the parameter list of TT depends on earlier parameters. */
6876 {
6881 }
6885 /* Argument is a parameter pack but parameter is not. */
6892 }
6895 }
6897 /* Coerce template argument list ARGLIST for use with template
6898 template-parameter TEMPL. */
6900 static tree
6902 tsubst_flags_t complain)
6903 {
6904 /* Consider an example where a template template parameter declared as
6906 template <class T, class U = std::allocator<T> > class TT
6908 The template parameter level of T and U are one level larger than
6909 of TT. To proper process the default argument of U, say when an
6910 instantiation `TT<int>' is seen, we need to build the full
6911 arguments containing {int} as the innermost level. Outer levels,
6912 available when not appearing as default template argument, can be
6913 obtained from the arguments of the enclosing template.
6915 Suppose that TT is later substituted with std::vector. The above
6916 instantiation is `TT<int, std::allocator<T> >' with TT at
6917 level 1, and T at level 2, while the template arguments at level 1
6918 becomes {std::vector} and the inner level 2 is {int}. */
6922 {
6924 /* We want arguments for the partial specialization, not arguments for
6925 the primary template. */
6927 else
6929 }
6931 {
6932 /* This is an argument of the current template, so we haven't set
6933 DECL_CONTEXT yet. */
6934 tree relevant_template_parms;
6936 /* Parameter levels that are greater than the level of the given
6937 template template parm are irrelevant. */
6944 }
6951 complain,
6954 }
6956 /* A cache of template template parameters with match-all default
6957 arguments. */
6959 static void
6961 {
6965 }
6966 static tree
6968 {
6973 }
6975 /* T is a bound template template-parameter. Copy its arguments into default
6976 arguments of the template template-parameter's template parameters. */
6978 static tree
6980 {
7003 {
7006 {
7009 }
7010 }
7014 }
7016 /* ARG is a bound potential template template-argument, and PARGS is a list
7017 of arguments for the corresponding template template-parameter. Adjust
7018 PARGS as appropriate for application to ARG's template, and if ARG is a
7019 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7020 arguments to the template template parameter. */
7022 static tree
7024 {
7028 {
7029 /* When comparing two template template-parameters in partial ordering,
7030 rewrite the one currently being used as an argument to have default
7031 arguments for all parameters. */
7037 }
7038 else
7039 {
7040 tree aparms
7045 }
7048 }
7050 /* Subroutine of unify for the case when PARM is a
7051 BOUND_TEMPLATE_TEMPLATE_PARM. */
7053 static int
7056 {
7060 /* The template template parm might be variadic and the argument
7061 not, so flatten both argument lists. */
7067 {
7068 /* In keeping with P0522R0, adjust P's template arguments
7069 to apply to A's template; then flatten it again. */
7072 }
7078 /* If the P0522 adjustment eliminated a pack expansion, deduce
7079 empty packs. */
7087 }
7089 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7090 template template parameters. Both PARM_PARMS and ARG_PARMS are
7091 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7092 or PARM_DECL.
7094 Consider the example:
7095 template <class T> class A;
7096 template<template <class U> class TT> class B;
7098 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7099 the parameters to A, and OUTER_ARGS contains A. */
7101 static int
7103 tree arg_parms,
7104 tsubst_flags_t complain,
7105 tree in_decl,
7106 tree outer_args)
7107 {
7119 {
7120 /* P0522R0: A template template-parameter P is at least as specialized as
7121 a template template-argument A if, given the following rewrite to two
7122 function templates, the function template corresponding to P is at
7123 least as specialized as the function template corresponding to A
7124 according to the partial ordering rules for function templates
7125 ([temp.func.order]). Given an invented class template X with the
7126 template parameter list of A (including default arguments):
7128 * Each of the two function templates has the same template parameters,
7129 respectively, as P or A.
7131 * Each function template has a single function parameter whose type is
7132 a specialization of X with template arguments corresponding to the
7133 template parameters from the respective function template where, for
7134 each template parameter PP in the template parameter list of the
7135 function template, a corresponding template argument AA is formed. If
7136 PP declares a parameter pack, then AA is the pack expansion
7137 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7139 If the rewrite produces an invalid type, then P is not at least as
7140 specialized as A. */
7142 /* So coerce P's args to apply to A's parms, and then deduce between A's
7143 args and the converted args. If that succeeds, A is at least as
7144 specialized as P, so they match.*/
7151 {
7157 }
7158 }
7160 /* Determine whether we have a parameter pack at the end of the
7161 template template parameter's template parameter list. */
7163 {
7170 {
7184 }
7185 }
7191 /* Check all of the template parameters except the parameter pack at
7192 the end (if any). */
7194 {
7203 outer_args))
7206 }
7209 {
7210 /* Check each of the template parameters in the template
7211 argument against the template parameter pack at the end of
7212 the template template parameter. */
7219 {
7226 outer_args))
7228 }
7229 }
7232 }
7234 /* Verifies that the deduced template arguments (in TARGS) for the
7235 template template parameters (in TPARMS) represent valid bindings,
7236 by comparing the template parameter list of each template argument
7237 to the template parameter list of its corresponding template
7238 template parameter, in accordance with DR150. This
7239 routine can only be called after all template arguments have been
7240 deduced. It will return TRUE if all of the template template
7241 parameter bindings are okay, FALSE otherwise. */
7242 bool
7244 {
7248 /* We're dealing with template parms in this process. */
7254 {
7259 {
7264 {
7265 /* Look inside the argument pack. */
7268 }
7271 {
7275 /* Extract the next argument from the argument
7276 pack. */
7280 /* Look at the pattern of the pack expansion. */
7283 /* Extract the template parameters from the template
7284 argument. */
7290 /* Verify that we can coerce the template template
7291 parameters from the template argument to the template
7292 parameter. This requires an exact match. */
7294 && !coerce_template_template_parms
7296 targ_parms,
7297 tf_none,
7298 tparm,
7299 targs))
7300 {
7303 }
7304 }
7305 }
7306 }
7308 out:
7312 }
7314 /* Since type attributes aren't mangled, we need to strip them from
7315 template type arguments. */
7317 static tree
7319 {
7329 }
7331 /* And from inside dependent non-type arguments like sizeof(Type). */
7333 static tree
7335 {
7345 }
7347 // A template declaration can be substituted for a constrained
7348 // template template parameter only when the argument is more
7349 // constrained than the parameter.
7350 static bool
7352 {
7355 /* For now, allow constrained template template arguments
7356 and unconstrained template template parameters. */
7362 // If the template parameter is constrained, we need to rewrite its
7363 // constraints in terms of the ARG's template parameters. This ensures
7364 // that all of the template parameter types will have the same depth.
7365 //
7366 // Note that this is only valid when coerce_template_template_parm is
7367 // true for the innermost template parameters of PARM and ARG. In other
7368 // words, because coercion is successful, this conversion will be valid.
7370 {
7377 }
7380 }
7382 // Convert a placeholder argument into a binding to the original
7383 // parameter. The original parameter is saved as the TREE_TYPE of
7384 // ARG.
7387 {
7390 }
7392 /* Convert the indicated template ARG as necessary to match the
7393 indicated template PARM. Returns the converted ARG, or
7394 error_mark_node if the conversion was unsuccessful. Error and
7395 warning messages are issued under control of COMPLAIN. This
7396 conversion is for the Ith parameter in the parameter list. ARGS is
7397 the full set of template arguments deduced so far. */
7399 static tree
7401 tree arg,
7402 tree args,
7403 tsubst_flags_t complain,
7405 tree in_decl)
7406 {
7407 tree orig_arg;
7408 tree val;
7414 /* Trivially convert placeholders. */
7423 {
7424 /* The template argument was the name of some
7425 member function. That's usually
7426 invalid, but static members are OK. In any
7427 case, grab the underlying fields/functions
7428 and issue an error later if required. */
7431 }
7439 /* When determining whether an argument pack expansion is a template,
7440 look at the pattern. */
7444 /* Deal with an injected-class-name used as a template template arg. */
7446 {
7449 {
7459 }
7460 }
7462 is_tmpl_type =
7478 {
7480 {
7484 }
7487 "to refer to a type member of a template parameter, "
7492 typename_type,
7493 complain);
7496 }
7498 {
7500 {
7502 {
7514 else
7517 }
7518 }
7520 }
7522 {
7524 {
7531 else
7534 }
7536 }
7539 {
7541 {
7545 /* The number of argument required is not known yet.
7546 Just accept it for now. */
7548 else
7549 {
7551 tree argparm;
7553 /* Strip alias templates that are equivalent to another
7554 template. */
7560 args))
7561 {
7564 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7565 TEMPLATE_DECL. */
7567 {
7572 }
7573 }
7574 else
7575 {
7577 {
7584 }
7587 }
7589 // Check that the constraints are compatible before allowing the
7590 // substitution.
7593 {
7595 {
7601 }
7603 }
7604 }
7605 }
7606 else
7608 /* We only form one instance of each template specialization.
7609 Therefore, if we use a non-canonical variant (i.e., a
7610 typedef), any future messages referring to the type will use
7611 the typedef, which is confusing if those future uses do not
7612 themselves also use the typedef. */
7615 }
7616 else
7617 {
7621 {
7623 /* There's nothing to check for an auto argument pack. */
7629 }
7630 else
7637 {
7640 else
7641 {
7642 /* Not sure if this is reachable, but it doesn't hurt
7643 to be robust. */
7646 }
7647 }
7650 /* We used to call digest_init here. However, digest_init
7651 will report errors, which we don't want when complain
7652 is zero. More importantly, digest_init will try too
7653 hard to convert things: for example, `0' should not be
7654 converted to pointer type at this point according to
7655 the standard. Accepting this is not merely an
7656 extension, since deciding whether or not these
7657 conversions can occur is part of determining which
7658 function template to call, or whether a given explicit
7659 argument specification is valid. */
7661 else
7671 {
7672 /* Reject template arguments that are references to built-in
7673 functions with no library fallbacks. */
7682 }
7685 {
7686 /* Strip typedefs from the SCOPE_REF. */
7689 complain);
7692 }
7693 }
7696 }
7698 /* Coerces the remaining template arguments in INNER_ARGS (from
7699 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
7700 Returns the coerced argument pack. PARM_IDX is the position of this
7701 parameter in the template parameter list. ARGS is the original
7702 template argument list. */
7703 static tree
7706 tree args,
7707 tree inner_args,
7709 tree new_args,
7711 tree in_decl,
7712 tsubst_flags_t complain)
7713 {
7716 tree packed_args;
7717 tree argument_pack;
7724 {
7725 /* When the template parameter is a non-type template parameter pack
7726 or template template parameter pack whose type or template
7727 parameters use parameter packs, we know exactly how many arguments
7728 we are looking for. Build a vector of the instantiated decls for
7729 these template parameters in PACKED_PARMS. */
7730 /* We can't use make_pack_expansion here because it would interpret a
7731 _DECL as a use rather than a declaration. */
7745 /* If we're doing a partial instantiation of a member template,
7746 verify that all of the types used for the non-type
7747 template parameter pack are, in fact, valid for non-type
7748 template parameters. */
7751 {
7754 {
7758 }
7759 /* We don't know how many args we have yet, just
7760 use the unconverted ones for now. */
7762 }
7765 }
7766 /* Check if we have a placeholder pack, which indicates we're
7767 in the context of a introduction list. In that case we want
7768 to match this pack to the single placeholder. */
7772 {
7775 }
7776 else
7779 /* Convert the remaining arguments, which will be a part of the
7780 parameter pack "parm". */
7783 {
7789 {
7790 /* Once we've packed as many args as we have types, stop. */
7794 /* We don't know how many args we have yet, just
7795 use the unconverted ones for now. */
7797 else
7799 }
7802 {
7805 }
7806 else
7809 in_decl);
7813 }
7817 {
7822 }
7827 else
7828 {
7833 }
7840 }
7842 /* Returns the number of pack expansions in the template argument vector
7843 ARGS. */
7845 static int
7847 {
7852 {
7856 }
7858 }
7860 /* Convert all template arguments to their appropriate types, and
7861 return a vector containing the innermost resulting template
7862 arguments. If any error occurs, return error_mark_node. Error and
7863 warning messages are issued under control of COMPLAIN.
7865 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
7866 for arguments not specified in ARGS. Otherwise, if
7867 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
7868 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
7869 USE_DEFAULT_ARGS is false, then all arguments must be specified in
7870 ARGS. */
7872 static tree
7874 tree args,
7875 tree in_decl,
7876 tsubst_flags_t complain,
7879 {
7881 tree orig_inner_args;
7882 tree inner_args;
7883 tree new_args;
7884 tree new_inner_args;
7888 /* When used as a boolean value, indicates whether this is a
7889 variadic template parameter list. Since it's an int, we can also
7890 subtract it from nparms to get the number of non-variadic
7891 parameters. */
7896 /* Likewise for parameters with default arguments. */
7904 /* Determine if there are any parameter packs or default arguments. */
7906 {
7914 }
7917 /* If there are no parameters that follow a parameter pack, we need to
7918 expand any argument packs so that we can deduce a parameter pack from
7919 some non-packed args followed by an argument pack, as in variadic85.C.
7920 If there are such parameters, we need to leave argument packs intact
7921 so the arguments are assigned properly. This can happen when dealing
7922 with a nested class inside a partial specialization of a class
7923 template, as in variadic92.C, or when deducing a template parameter pack
7924 from a sub-declarator, as in variadic114.C. */
7928 /* Count any pack expansion args. */
7934 && require_all_args
7935 && !variadic_args_p
7936 && (!use_default_args
7939 {
7941 {
7943 {
7947 }
7948 else
7955 }
7958 }
7959 /* We can't pass a pack expansion to a non-pack parameter of an alias
7960 template (DR 1430). */
7964 && variadic_args_p
7966 {
7968 {
7970 {
7976 {
7979 "pack expansion argument for non-pack parameter "
7981 else
7983 "pack expansion argument for non-pack parameter "
7987 }
7988 }
7990 found:;
7991 }
7993 }
7995 /* We need to evaluate the template arguments, even though this
7996 template-id may be nested within a "sizeof". */
8005 {
8006 tree arg;
8007 tree parm;
8009 /* Get the Ith template parameter. */
8013 {
8016 }
8018 /* Calculate the next argument. */
8021 else
8026 {
8027 /* Some arguments will be placed in the
8028 template parameter pack PARM. */
8035 {
8036 /* We don't know how many args we have yet, just use the
8037 unconverted (and still packed) ones for now. */
8041 }
8045 /* Store this argument. */
8047 {
8048 lost++;
8049 /* We are done with all of the arguments. */
8051 }
8052 else
8053 {
8056 }
8059 }
8061 {
8063 {
8064 /* "If every valid specialization of a variadic template
8065 requires an empty template parameter pack, the template is
8066 ill-formed, no diagnostic required." So check that the
8067 pattern works with this parameter. */
8072 in_decl);
8074 {
8079 }
8081 /* Recover from missing typename. */
8085 /* We don't know how many args we have yet, just
8086 use the unconverted ones for now. */
8090 }
8091 }
8093 {
8094 /* There must be a default arg in this case. */
8097 /* The position of the first default template argument,
8098 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8099 Record that. */
8103 }
8104 else
8108 {
8111 }
8113 /* This only occurs if there was an error in the template
8114 parameter list itself (which we would already have
8115 reported) that we are trying to recover from, e.g., a class
8116 template with a parameter list such as
8117 template<typename..., typename>. */
8119 else
8125 lost++;
8127 }
8132 {
8134 {
8139 }
8141 }
8151 }
8153 /* Convert all template arguments to their appropriate types, and
8154 return a vector containing the innermost resulting template
8155 arguments. If any error occurs, return error_mark_node. Error and
8156 warning messages are not issued.
8158 Note that no function argument deduction is performed, and default
8159 arguments are used to fill in unspecified arguments. */
8160 tree
8162 {
8164 }
8166 /* Convert all template arguments to their appropriate type, and
8167 instantiate default arguments as needed. This returns a vector
8168 containing the innermost resulting template arguments, or
8169 error_mark_node if unsuccessful. */
8170 tree
8172 tsubst_flags_t complain)
8173 {
8175 }
8177 /* Like coerce_template_parms. If PARMS represents all template
8178 parameters levels, this function returns a vector of vectors
8179 representing all the resulting argument levels. Note that in this
8180 case, only the innermost arguments are coerced because the
8181 outermost ones are supposed to have been coerced already.
8183 Otherwise, if PARMS represents only (the innermost) vector of
8184 parameters, this function returns a vector containing just the
8185 innermost resulting arguments. */
8187 static tree
8189 tree args,
8190 tree in_decl,
8191 tsubst_flags_t complain,
8194 {
8197 tree coerced_args;
8200 {
8202 tree level;
8208 {
8209 tree l;
8213 require_all_args,
8214 use_default_args);
8215 else
8222 }
8223 }
8224 else
8227 require_all_args,
8228 use_default_args);
8230 }
8232 /* Returns 1 if template args OT and NT are equivalent. */
8234 int
8236 {
8245 /* For member templates */
8254 {
8271 }
8275 {
8278 /* Don't treat an alias template specialization with dependent
8279 arguments as equivalent to its underlying type when used as a
8280 template argument; we need them to be distinct so that we
8281 substitute into the specialization arguments at instantiation
8282 time. And aliases can't be equivalent without being ==, so
8283 we don't need to look any deeper. */
8286 else
8288 }
8291 else
8292 {
8293 /* Try to treat a template non-type argument that has been converted
8294 to the parameter type as equivalent to one that hasn't yet. */
8307 }
8308 }
8310 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8311 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8312 NEWARG_PTR with the offending arguments if they are non-NULL. */
8314 int
8317 {
8330 {
8335 {
8341 }
8342 }
8344 }
8346 static void
8348 {
8358 /* We are called both from instantiate_decl, where we've already had a
8359 tinst_level pushed, and instantiate_template, where we haven't.
8360 Compensate. */
8371 else
8380 }
8383 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
8384 ARGLIST. Valid choices for FNS are given in the cp-tree.def
8385 documentation for TEMPLATE_ID_EXPR. */
8387 tree
8389 {
8390 tree type;
8398 {
8401 }
8404 {
8406 unknown_type_node,
8408 arglist);
8410 }
8417 }
8419 /* Within the scope of a template class S<T>, the name S gets bound
8420 (in build_self_reference) to a TYPE_DECL for the class, not a
8421 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
8422 or one of its enclosing classes, and that type is a template,
8423 return the associated TEMPLATE_DECL. Otherwise, the original
8424 DECL is returned.
8426 Also handle the case when DECL is a TREE_LIST of ambiguous
8427 injected-class-names from different bases. */
8429 tree
8431 {
8435 /* DR 176: A lookup that finds an injected-class-name (10.2
8436 [class.member.lookup]) can result in an ambiguity in certain cases
8437 (for example, if it is found in more than one base class). If all of
8438 the injected-class-names that are found refer to specializations of
8439 the same class template, and if the name is followed by a
8440 template-argument-list, the reference refers to the class template
8441 itself and not a specialization thereof, and is not ambiguous. */
8443 {
8446 {
8452 }
8455 else
8457 }
8463 }
8465 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
8466 parameters, find the desired type.
8468 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
8470 IN_DECL, if non-NULL, is the template declaration we are trying to
8471 instantiate.
8473 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
8474 the class we are looking up.
8476 Issue error and warning messages under control of COMPLAIN.
8478 If the template class is really a local class in a template
8479 function, then the FUNCTION_CONTEXT is the function in which it is
8480 being instantiated.
8482 ??? Note that this function is currently called *twice* for each
8483 template-id: the first time from the parser, while creating the
8484 incomplete type (finish_template_type), and the second type during the
8485 real instantiation (instantiate_template_class). This is surely something
8486 that we want to avoid. It also causes some problems with argument
8487 coercion (see convert_nontype_argument for more information on this). */
8489 static tree
8492 {
8494 tree t;
8497 spec_entry elt;
8498 hashval_t hash;
8501 {
8505 else
8506 {
8513 }
8516 }
8518 {
8521 /* If we are declaring a constructor, say A<T>::A<T>, we will get
8522 an implicit typename for the second A. Deal with it. */
8527 {
8530 }
8531 }
8534 {
8537 }
8539 {
8543 }
8545 {
8548 }
8550 /* Issue an error message if we didn't find a template. */
8552 {
8556 }
8559 /* Make sure it's a user visible template, if it was named by
8560 the user. */
8563 {
8565 {
8569 }
8571 }
8575 /* An alias that just changes the name of a template is equivalent to the
8576 other template, so if any of the arguments are pack expansions, strip
8577 the alias to avoid problems with a pack expansion passed to a non-pack
8578 alias template parameter (DR 1430). */
8583 {
8584 tree parm;
8593 }
8594 else
8595 {
8597 tree gen_tmpl;
8598 tree type_decl;
8606 /* An error occurred while building the template TEMPL, and a
8607 diagnostic has most certainly been emitted for that
8608 already. Let's propagate that error. */
8617 {
8618 /* We've been given an incomplete set of template arguments.
8619 For example, given:
8621 template <class T> struct S1 {
8622 template <class U> struct S2 {};
8623 template <class U> struct S2<U*> {};
8624 };
8626 we will be called with an ARGLIST of `U*', but the
8627 TEMPLATE will be `template <class T> template
8628 <class U> struct S1<T>::S2'. We must fill in the missing
8629 arguments. */
8633 }
8635 /* Now we should have enough arguments. */
8638 /* From here on, we're only interested in the most general
8639 template. */
8641 /* Calculate the BOUND_ARGS. These will be the args that are
8642 actually tsubst'd into the definition to create the
8643 instantiation. */
8645 complain,
8650 /* We were unable to bind the arguments. */
8653 /* In the scope of a template class, explicit references to the
8654 template class refer to the type of the template, not any
8655 instantiation of it. For example, in:
8657 template <class T> class C { void f(C<T>); }
8659 the `C<T>' is just the same as `C'. Outside of the
8660 class, however, such a reference is an instantiation. */
8664 {
8669 }
8671 /* If we already have this specialization, return it. */
8681 /* If the the template's constraints are not satisfied,
8682 then we cannot form a valid type.
8684 Note that the check is deferred until after the hash
8685 lookup. This prevents redundant checks on previously
8686 instantiated specializations. */
8688 {
8690 {
8693 }
8695 }
8699 /* If the deduced arguments are invalid, then the binding
8700 failed. */
8704 complain))
8711 {
8716 }
8726 /* Create the type. */
8728 {
8729 /* The user referred to a specialization of an alias
8730 template represented by GEN_TMPL.
8732 [temp.alias]/2 says:
8734 When a template-id refers to the specialization of an
8735 alias template, it is equivalent to the associated
8736 type obtained by substitution of its
8737 template-arguments for the template-parameters in the
8738 type-id of the alias template. */
8741 /* Note that the call above (by indirectly calling
8742 register_specialization in tsubst_decl) registers the
8743 TYPE_DECL representing the specialization of the alias
8744 template. So next time someone substitutes ARGLIST for
8745 the template parms into the alias template (GEN_TMPL),
8746 she'll get that TYPE_DECL back. */
8750 }
8752 {
8754 {
8765 }
8766 else
8767 {
8768 /* We don't want to call start_enum for this type, since
8769 the values for the enumeration constants may involve
8770 template parameters. And, no one should be interested
8771 in the enumeration constants for such a type. */
8774 }
8778 }
8780 {
8786 /* A local class. Make sure the decl gets registered properly. */
8791 /* This instantiation is another name for the primary
8792 template type. Set the TYPE_CANONICAL field
8793 appropriately. */
8796 /* Some of the template arguments require structural
8797 equality testing, so this template class requires
8798 structural equality testing. */
8800 }
8801 else
8804 /* If we called start_enum or pushtag above, this information
8805 will already be set up. */
8807 {
8814 }
8815 else
8819 {
8825 {
8828 }
8829 }
8833 {
8837 {
8838 tree attributes
8846 }
8847 }
8849 /* Let's consider the explicit specialization of a member
8850 of a class template specialization that is implicitly instantiated,
8851 e.g.:
8852 template<class T>
8853 struct S
8854 {
8855 template<class U> struct M {}; //#0
8856 };
8858 template<>
8859 template<>
8860 struct S<int>::M<char> //#1
8861 {
8862 int i;
8863 };
8864 [temp.expl.spec]/4 says this is valid.
8866 In this case, when we write:
8867 S<int>::M<char> m;
8869 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
8870 the one of #0.
8872 When we encounter #1, we want to store the partial instantiation
8873 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
8875 For all cases other than this "explicit specialization of member of a
8876 class template", we just want to store the most general template into
8877 the CLASSTYPE_TI_TEMPLATE of M.
8879 This case of "explicit specialization of member of a class template"
8880 only happens when:
8881 1/ the enclosing class is an instantiation of, and therefore not
8882 the same as, the context of the most general template, and
8883 2/ we aren't looking at the partial instantiation itself, i.e.
8884 the innermost arguments are not the same as the innermost parms of
8885 the most general template.
8887 So it's only when 1/ and 2/ happens that we want to use the partial
8888 instantiation of the member template in lieu of its most general
8889 template. */
8893 /* the enclosing class must be an instantiation... */
8896 {
8900 tree partial_inst_args =
8907 use_partial_inst_tmpl =
8908 /*...and we must not be looking at the partial instantiation
8909 itself. */
8911 partial_inst_args);
8912 }
8915 /* This case is easy; there are no member templates involved. */
8917 else
8918 {
8919 /* This is a full instantiation of a member template. Find
8920 the partial instantiation of which this is an instance. */
8922 /* Temporarily reduce by one the number of levels in the ARGLIST
8923 so as to avoid comparing the last set of arguments. */
8927 /* FOUND is either a proper class type, or an alias
8928 template specialization. In the later case, it's a
8929 TYPE_DECL, resulting from the substituting of arguments
8930 for parameters in the TYPE_DECL of the alias template
8931 done earlier. So be careful while getting the template
8932 of FOUND. */
8934 ? found
8938 }
8940 // Build template info for the new specialization.
8949 /* Note this use of the partial instantiation so we can check it
8950 later in maybe_process_partial_specialization. */
8957 /* Now that the type has been registered on the instantiations
8958 list, we set up the enumerators. Because the enumeration
8959 constants may involve the enumeration type itself, we make
8960 sure to register the type first, and then create the
8961 constants. That way, doing tsubst_expr for the enumeration
8962 constants won't result in recursive calls here; we'll find
8963 the instantiation and exit above. */
8967 /* If the type makes use of template parameters, the
8968 code that generates debugging information will crash. */
8971 /* Possibly limit visibility based on template args. */
8978 }
8979 }
8981 /* Wrapper for lookup_template_class_1. */
8983 tree
8986 {
8987 tree ret;
8993 }
8995 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
8997 tree
8999 {
9000 /* The type of the expression is NULL_TREE since the template-id could refer
9001 to an explicit or partial specialization. */
9004 /* Except that concepts are always bool. */
9007 }
9009 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9011 tree
9013 {
9017 /* We never want to return a VAR_DECL for a variable concept, since they
9018 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
9033 {
9035 {
9038 }
9040 }
9042 /* If a template-id refers to a specialization of a variable
9043 concept, then the expression is true if and only if the
9044 concept's constraints are satisfied by the given template
9045 arguments.
9047 NOTE: This is an extension of Concepts Lite TS that
9048 allows constraints to be used in expressions. */
9050 {
9053 }
9056 }
9058 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
9059 TARGS template args, and instantiate it if it's not dependent. */
9061 tree
9063 tsubst_flags_t complain)
9064 {
9067 {
9070 }
9073 }
9075 \f
9076 struct pair_fn_data
9077 {
9078 tree_fn_t fn;
9079 tree_fn_t any_fn;
9081 /* True when we should also visit template parameters that occur in
9082 non-deduced contexts. */
9085 };
9087 /* Called from for_each_template_parm via walk_tree. */
9089 static tree
9091 {
9098 #define WALK_SUBTREE(NODE) \
9099 do \
9100 { \
9101 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
9102 pfd->include_nondeduced_p, \
9103 pfd->any_fn); \
9104 if (result) goto out; \
9105 } \
9106 while (0)
9116 {
9120 /* Fall through. */
9126 else
9136 /* Since we're not going to walk subtrees, we have to do this
9137 explicitly here. */
9139 /* Fall through. */
9142 /* Check the return type. */
9145 /* Check the parameter types. Since default arguments are not
9146 instantiated until they are needed, the TYPE_ARG_TYPES may
9147 contain expressions that involve template parameters. But,
9148 no-one should be looking at them yet. And, once they're
9149 instantiated, they don't contain template parameters, so
9150 there's no point in looking at them then, either. */
9151 {
9152 tree parm;
9157 /* Since we've already handled the TYPE_ARG_TYPES, we don't
9158 want walk_tree walking into them itself. */
9160 }
9163 {
9167 }
9184 /* Fall through. */
9196 /* Record template parameters such as `T' inside `TT<T>'. */
9198 /* Fall through. */
9210 /* A template template parameter is encountered. */
9214 /* Already substituted template template parameter */
9219 /* A template-id in a TYPENAME_TYPE might be a deduced context after
9220 partial instantiation. */
9232 /* If there's no type, then this thing must be some expression
9233 involving template parameters. */
9255 }
9257 #undef WALK_SUBTREE
9259 /* We didn't find any template parameters we liked. */
9260 out:
9262 }
9264 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9265 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9266 call FN with the parameter and the DATA.
9267 If FN returns nonzero, the iteration is terminated, and
9268 for_each_template_parm returns 1. Otherwise, the iteration
9269 continues. If FN never returns a nonzero value, the value
9270 returned by for_each_template_parm is 0. If FN is NULL, it is
9271 considered to be the function which always returns 1.
9273 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9274 parameters that occur in non-deduced contexts. When false, only
9275 visits those template parameters that can be deduced. */
9277 static tree
9281 tree_fn_t any_fn)
9282 {
9284 tree result;
9286 /* Set up. */
9292 /* Walk the tree. (Conceptually, we would like to walk without
9293 duplicates, but for_each_template_parm_r recursively calls
9294 for_each_template_parm, so we would need to reorganize a fair
9295 bit to use walk_tree_without_duplicates, so we keep our own
9296 visited list.) */
9299 else
9302 for_each_template_parm_r,
9306 /* Clean up. */
9308 {
9311 }
9314 }
9316 /* Returns true if T depends on any template parameter. */
9318 int
9320 {
9350 else
9351 {
9354 }
9359 }
9361 /* Returns true iff current_function_decl is an incompletely instantiated
9362 template. Useful instead of processing_template_decl because the latter
9363 is set to 0 during instantiate_non_dependent_expr. */
9365 bool
9367 {
9376 }
9378 /* Returns true if T depends on any template parameter with level LEVEL. */
9380 bool
9382 {
9385 }
9387 /* Returns true if the signature of DECL depends on any template parameter from
9388 its enclosing class. */
9390 bool
9392 {
9402 template_parm_outer_level,
9412 }
9414 /* Returns TRUE iff INST is an instantiation we don't need to do in an
9415 ill-formed translation unit, i.e. a variable or function that isn't
9416 usable in a constant expression. */
9420 {
9424 }
9426 /* Returns TRUE iff we should refuse to instantiate DECL because it's
9427 neglectable and instantiated from within an erroneous instantiation. */
9429 static bool
9431 {
9442 }
9450 /* We're starting to instantiate D; record the template instantiation context
9451 for diagnostics and to restore it later. */
9453 bool
9455 {
9457 }
9459 /* We're starting to instantiate D; record the template instantiation context
9460 at LOC for diagnostics and to restore it later. */
9462 bool
9464 {
9468 {
9469 /* Tell error.c not to try to instantiate any templates. */
9472 "template instantiation depth exceeds maximum of %d"
9474 max_tinst_depth);
9476 }
9478 /* If the current instantiation caused problems, don't let it instantiate
9479 anything else. Do allow deduction substitution and decls usable in
9480 constant expressions. */
9484 /* When not -quiet, dump template instantiations other than functions, since
9485 announce_function will take care of those. */
9504 }
9506 /* We're done instantiating this template; return to the instantiation
9507 context. */
9509 void
9511 {
9512 /* Restore the filename and line number stashed away when we started
9513 this instantiation. */
9517 }
9519 /* We're instantiating a deferred template; restore the template
9520 instantiation context in which the instantiation was requested, which
9521 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
9523 static tree
9525 {
9537 }
9539 /* Returns the TINST_LEVEL which gives the original instantiation
9540 context. */
9544 {
9550 }
9552 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
9553 vector of template arguments, as for tsubst.
9555 Returns an appropriate tsubst'd friend declaration. */
9557 static tree
9559 {
9560 tree new_friend;
9565 /* This was a friend declared with an explicit template
9566 argument list, e.g.:
9568 friend void f<>(T);
9570 to indicate that f was a template instantiation, not a new
9571 function declaration. Now, we have to figure out what
9572 instantiation of what template. */
9573 {
9575 tree new_args;
9576 tree tmpl;
9579 /* Friend functions are looked up in the containing namespace scope.
9580 We must enter that scope, to avoid finding member functions of the
9581 current class with same name. */
9596 tsk_none);
9598 }
9602 /* The NEW_FRIEND will look like an instantiation, to the
9603 compiler, but is not an instantiation from the point of view of
9604 the language. For example, we might have had:
9606 template <class T> struct S {
9607 template <class U> friend void f(T, U);
9608 };
9610 Then, in S<int>, template <class U> void f(int, U) is not an
9611 instantiation of anything. */
9617 {
9621 }
9623 /* The mangled name for the NEW_FRIEND is incorrect. The function
9624 is not a template instantiation and should not be mangled like
9625 one. Therefore, we forget the mangling here; we'll recompute it
9626 later if we need it. */
9628 {
9631 }
9634 {
9635 tree old_decl;
9636 tree new_friend_template_info;
9637 tree new_friend_result_template_info;
9638 tree ns;
9641 /* We must save some information from NEW_FRIEND before calling
9642 duplicate decls since that function will free NEW_FRIEND if
9643 possible. */
9645 new_friend_is_defn =
9650 {
9651 /* This declaration is a `primary' template. */
9654 new_friend_result_template_info
9656 }
9657 else
9660 /* Inside pushdecl_namespace_level, we will push into the
9661 current namespace. However, the friend function should go
9662 into the namespace of the template. */
9672 {
9673 /* This new friend declaration matched an existing
9674 declaration. For example, given:
9676 template <class T> void f(T);
9677 template <class U> class C {
9678 template <class T> friend void f(T) {}
9679 };
9681 the friend declaration actually provides the definition
9682 of `f', once C has been instantiated for some type. So,
9683 old_decl will be the out-of-class template declaration,
9684 while new_friend is the in-class definition.
9686 But, if `f' was called before this point, the
9687 instantiation of `f' will have DECL_TI_ARGS corresponding
9688 to `T' but not to `U', references to which might appear
9689 in the definition of `f'. Previously, the most general
9690 template for an instantiation of `f' was the out-of-class
9691 version; now it is the in-class version. Therefore, we
9692 run through all specialization of `f', adding to their
9693 DECL_TI_ARGS appropriately. In particular, they need a
9694 new set of outer arguments, corresponding to the
9695 arguments for this class instantiation.
9697 The same situation can arise with something like this:
9699 friend void f(int);
9700 template <class T> class C {
9701 friend void f(T) {}
9702 };
9704 when `C<int>' is instantiated. Now, `f(int)' is defined
9705 in the class. */
9708 /* On the other hand, if the in-class declaration does
9709 *not* provide a definition, then we don't want to alter
9710 existing definitions. We can just leave everything
9711 alone. */
9712 ;
9713 else
9714 {
9718 /* Overwrite whatever template info was there before, if
9719 any, with the new template information pertaining to
9720 the declaration. */
9724 {
9725 /* We should have called reregister_specialization in
9726 duplicate_decls. */
9731 /* Instantiate it if the global has already been used. */
9735 }
9736 else
9737 {
9738 tree t;
9740 /* Indicate that the old function template is a partial
9741 instantiation. */
9749 /* Reassign any specializations already in the hash table
9750 to the new more general template, and add the
9751 additional template args. */
9755 {
9757 spec_entry elt;
9769 register_specialization
9772 }
9774 }
9775 }
9777 /* The information from NEW_FRIEND has been merged into OLD_DECL
9778 by duplicate_decls. */
9780 }
9781 }
9782 else
9783 {
9787 /* In the code
9788 template <class T> class C {
9789 template <class U> friend void C1<U>::f (); // case 1
9790 friend void C2<T>::f (); // case 2
9791 };
9792 we only need to make sure CONTEXT is a complete type for
9793 case 2. To distinguish between the two cases, we note that
9794 CONTEXT of case 1 remains dependent type after tsubst while
9795 this isn't true for case 2. */
9805 {
9807 /* do_friend adds the TEMPLATE_DECL for any member friend
9808 template even if it isn't a member template, i.e.
9809 template <class T> friend A<T>::f();
9810 Look through it in that case. */
9814 /* Check to see that the declaration is really present, and,
9815 possibly obtain an improved declaration. */
9820 }
9821 }
9824 }
9826 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
9827 template arguments, as for tsubst.
9829 Returns an appropriate tsubst'd friend type or error_mark_node on
9830 failure. */
9832 static tree
9834 {
9835 tree friend_type;
9836 tree tmpl;
9837 tree context;
9840 {
9843 }
9848 {
9851 else
9853 }
9855 /* Look for a class template declaration. We look for hidden names
9856 because two friend declarations of the same template are the
9857 same. For example, in:
9859 struct A {
9860 template <typename> friend class F;
9861 };
9862 template <typename> struct B {
9863 template <typename> friend class F;
9864 };
9866 both F templates are the same. */
9870 /* But, if we don't find one, it might be because we're in a
9871 situation like this:
9873 template <class T>
9874 struct S {
9875 template <class U>
9876 friend struct S;
9877 };
9879 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
9880 for `S<int>', not the TEMPLATE_DECL. */
9882 {
9885 }
9888 {
9889 /* The friend template has already been declared. Just
9890 check to see that the declarations match, and install any new
9891 default parameters. We must tsubst the default parameters,
9892 of course. We only need the innermost template parameters
9893 because that is all that redeclare_class_template will look
9894 at. */
9897 {
9898 tree parms;
9899 location_t saved_input_location;
9909 }
9912 }
9913 else
9914 {
9915 /* The friend template has not already been declared. In this
9916 case, the instantiation of the template class will cause the
9917 injection of this template into the global scope. */
9922 /* The new TMPL is not an instantiation of anything, so we
9923 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
9924 the new type because that is supposed to be the corresponding
9925 template decl, i.e., TMPL. */
9932 /* Inject this template into the global scope. */
9934 }
9937 {
9940 else
9942 }
9945 }
9947 /* Returns zero if TYPE cannot be completed later due to circularity.
9948 Otherwise returns one. */
9950 static int
9952 {
9962 else
9964 }
9969 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
9970 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
9972 static tree
9975 {
9984 {
9991 clauses
9995 else
9997 }
9998 /* If the first attribute argument is an identifier, don't
9999 pass it through tsubst. Attributes like mode, format,
10000 cleanup and several target specific attributes expect it
10001 unmodified. */
10003 {
10004 tree chain
10009 }
10011 {
10012 /* An attribute pack expansion. */
10019 {
10023 }
10025 }
10026 else
10033 }
10035 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
10036 unchanged or a new TREE_LIST chain. */
10038 static tree
10041 {
10046 {
10050 }
10054 {
10057 {
10060 {
10062 do
10067 }
10068 }
10070 }
10073 }
10075 /* Apply any attributes which had to be deferred until instantiation
10076 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
10077 ARGS, COMPLAIN, IN_DECL are as tsubst. */
10079 static void
10082 {
10084 tree t;
10091 {
10095 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
10096 to our attributes parameter. */
10098 }
10099 else
10100 {
10102 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
10103 lookup_template_class_1, and should be preserved. */
10107 }
10111 {
10115 }
10119 {
10124 {
10127 {
10131 do
10134 }
10135 else
10137 }
10140 }
10141 }
10143 /* Perform (or defer) access check for typedefs that were referenced
10144 from within the template TMPL code.
10145 This is a subroutine of instantiate_decl and instantiate_class_template.
10146 TMPL is the template to consider and TARGS is the list of arguments of
10147 that template. */
10149 static void
10151 {
10152 location_t saved_location;
10163 {
10175 /* Make access check error messages point to the location
10176 of the use of the typedef. */
10180 tf_warning_or_error);
10181 }
10183 }
10185 static tree
10187 {
10189 tree typedecl;
10190 tree pbinfo;
10191 tree base_list;
10193 tree fn_context;
10202 /* Figure out which template is being instantiated. */
10206 /* Determine what specialization of the original template to
10207 instantiate. */
10210 {
10213 }
10215 {
10216 /* This TYPE is actually an instantiation of a partial
10217 specialization. We replace the innermost set of ARGS with
10218 the arguments appropriate for substitution. For example,
10219 given:
10221 template <class T> struct S {};
10222 template <class T> struct S<T*> {};
10224 and supposing that we are instantiating S<int*>, ARGS will
10225 presently be {int*} -- but we need {int}. */
10228 }
10229 else
10230 {
10233 }
10235 /* If the template we're instantiating is incomplete, then clearly
10236 there's nothing we can do. */
10240 /* If we've recursively instantiated too many templates, stop. */
10244 /* Now we're really doing the instantiation. Mark the type as in
10245 the process of being defined. */
10248 /* We may be in the middle of deferred access check. Disable
10249 it now. */
10256 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10261 else
10262 {
10265 }
10266 /* Use #pragma pack from the template context. */
10272 /* Set the input location to the most specialized template definition.
10273 This is needed if tsubsting causes an error. */
10285 {
10288 /* Adjust visibility for template arguments. */
10290 }
10296 /* We should never instantiate a nested class before its enclosing
10297 class; we need to look up the nested class by name before we can
10298 instantiate it, and that lookup should instantiate the enclosing
10299 class. */
10305 {
10306 tree pbase_binfo;
10307 tree pushed_scope;
10310 /* We must enter the scope containing the type, as that is where
10311 the accessibility of types named in dependent bases are
10312 looked up from. */
10315 /* Substitute into each of the bases to determine the actual
10316 basetypes. */
10318 {
10319 tree base;
10325 {
10326 expanded_bases =
10333 }
10336 {
10338 /* Extract the already-expanded base class. */
10340 else
10341 /* Substitute to figure out the base class. */
10343 NULL_TREE);
10351 }
10352 }
10354 /* The list is now in reverse order; correct that. */
10359 }
10360 /* Now call xref_basetypes to set up all the base-class
10361 information. */
10369 /* Now that our base classes are set up, enter the scope of the
10370 class, so that name lookups into base classes, etc. will work
10371 correctly. This is precisely analogous to what we do in
10372 begin_class_definition when defining an ordinary non-template
10373 class, except we also need to push the enclosing classes. */
10376 /* Now members are processed in the order of declaration. */
10379 {
10383 {
10385 {
10386 /* Build new CLASSTYPE_NESTED_UTDS. */
10388 tree newtag;
10394 /* If the member is a class template, then -- even after
10395 substitution -- there may be dependent types in the
10396 template argument list for the class. We increment
10397 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
10398 that function will assume that no types are dependent
10399 when outside of a template. */
10409 {
10413 /* Unfortunately, lookup_template_class sets
10414 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
10415 instantiation (i.e., for the type of a member
10416 template class nested within a template class.)
10417 This behavior is required for
10418 maybe_process_partial_specialization to work
10419 correctly, but is not accurate in this case;
10420 the TAG is not an instantiation of anything.
10421 (The corresponding TEMPLATE_DECL is an
10422 instantiation, but the TYPE is not.) */
10425 /* Now, we call pushtag to put this NEWTAG into the scope of
10426 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
10427 pushtag calling push_template_decl. We don't have to do
10428 this for enums because it will already have been done in
10429 tsubst_enum. */
10433 }
10434 }
10436 {
10437 /* Build new TYPE_METHODS. */
10438 tree r;
10447 /* Instantiate members marked with attribute used. */
10453 }
10456 /* A closure type for a lambda in a default argument for a
10457 member template. Ignore it; it will be instantiated with
10459 else
10460 {
10461 /* Build new TYPE_FIELDS. */
10463 {
10464 tree condition;
10467 condition =
10477 }
10479 {
10480 tree r;
10484 /* The file and line for this declaration, to
10485 assist in error message reporting. Since we
10486 called push_tinst_level above, we don't need to
10487 restore these. */
10497 {
10498 /* A capture pack became multiple fields. */
10501 }
10504 {
10508 {
10509 /* In [temp.inst]:
10511 [t]he initialization (and any associated
10512 side-effects) of a static data member does
10513 not occur unless the static data member is
10514 itself used in a way that requires the
10515 definition of the static data member to
10516 exist.
10518 Therefore, we do not substitute into the
10519 initialized for the static data member here. */
10520 finish_static_data_member_decl
10526 /* Instantiate members marked with attribute used. */
10529 }
10531 {
10532 /* Determine whether R has a valid type and can be
10533 completed later. If R is invalid, then its type
10534 is replaced by error_mark_node. */
10540 {
10541 /* If R's type couldn't be completed and
10542 it isn't a flexible array member (whose
10543 type is incomplete by definition) give
10544 an error. */
10547 }
10548 }
10550 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10551 such a thing will already have been added to the field
10552 list by tsubst_enum in finish_member_declaration in the
10553 CLASSTYPE_NESTED_UTDS case above. */
10557 {
10560 }
10561 }
10562 }
10563 }
10564 }
10565 else
10566 {
10569 {
10570 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10576 {
10577 /* template <class T> friend class C; */
10580 }
10582 {
10583 /* template <class T> friend class C::D; */
10589 }
10592 {
10593 /* This could be either
10595 friend class T::C;
10597 when dependent_type_p is false or
10599 template <class U> friend class T::C;
10601 otherwise. */
10602 /* Bump processing_template_decl in case this is something like
10603 template <class T> friend struct A<T>::B. */
10610 }
10613 {
10614 /* friend class C;
10616 where C hasn't been declared yet. Let's lookup name
10617 from namespace scope directly, bypassing any name that
10618 come from dependent base class. */
10621 /* The call to xref_tag_from_type does injection for friend
10622 classes. */
10624 friend_type =
10628 }
10630 /* friend class C<T>; */
10633 /* Otherwise it's
10635 friend class C;
10637 where C is already declared or
10639 friend class C<int>;
10641 We don't have to do anything in these cases. */
10644 /* Trick make_friend_class into realizing that the friend
10645 we're adding is a template, not an ordinary class. It's
10646 important that we use make_friend_class since it will
10647 perform some error-checking and output cross-reference
10648 information. */
10656 }
10657 else
10658 {
10659 /* Build new DECL_FRIENDLIST. */
10660 tree r;
10662 /* The file and line for this declaration, to
10663 assist in error message reporting. Since we
10664 called push_tinst_level above, we don't need to
10665 restore these. */
10669 {
10672 }
10677 {
10680 }
10681 }
10682 }
10683 }
10686 {
10687 /* Restore these before substituting into the lambda capture
10688 initializers. */
10691 }
10694 {
10697 {
10703 {
10704 /* Set function_depth to avoid garbage collection. */
10708 }
10710 /* We need to instantiate the capture list from the template
10711 after we've instantiated the closure members, but before we
10712 consider adding the conversion op. Also keep any captures
10713 that may have been added during instantiation of the op(). */
10715 tree tmpl_cap
10724 }
10725 else
10727 }
10729 /* Set the file and line number information to whatever is given for
10730 the class itself. This puts error messages involving generated
10731 implicit functions at a predictable point, and the same point
10732 that would be used for non-template classes. */
10739 /* We don't instantiate default arguments for member functions. 14.7.1:
10741 The implicit instantiation of a class template specialization causes
10742 the implicit instantiation of the declarations, but not of the
10743 definitions or default arguments, of the class member functions,
10744 member classes, static data members and member templates.... */
10746 /* Some typedefs referenced from within the template code need to be access
10747 checked at template instantiation time, i.e now. These types were
10748 added to the template at parsing time. Let's get those and perform
10749 the access checks then. */
10759 /* The vtable for a template class can be emitted in any translation
10760 unit in which the class is instantiated. When there is no key
10761 method, however, finish_struct_1 will already have added TYPE to
10762 the keyed_classes list. */
10767 }
10769 /* Wrapper for instantiate_class_template_1. */
10771 tree
10773 {
10774 tree ret;
10779 }
10781 static tree
10783 {
10784 tree r;
10790 else
10791 {
10798 }
10800 }
10802 /* Given a function parameter pack TMPL_PARM and some function parameters
10803 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
10804 and set *SPEC_P to point at the next point in the list. */
10806 tree
10808 {
10809 /* Collect all of the extra "packed" parameters into an
10810 argument pack. */
10811 tree parmvec;
10812 tree parmtypevec;
10823 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
10828 {
10831 }
10833 /* Build the argument packs. */
10840 }
10842 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
10843 NONTYPE_ARGUMENT_PACK. */
10845 static tree
10847 {
10849 }
10851 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
10852 pack expansion with no extra args, 2 if it has extra args, or 0
10853 if it is not a pack expansion. */
10855 static int
10857 {
10863 /* A decl pack is itself an expansion. */
10870 }
10873 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
10875 static tree
10877 {
10884 }
10886 /* This is a subroutine of tsubst_pack_expansion.
10888 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
10889 mechanism to store the (non complete list of) arguments of the
10890 substitution and return a non substituted pack expansion, in order
10891 to wait for when we have enough arguments to really perform the
10892 substitution. */
10894 static bool
10898 {
10899 /* If one pack has an expansion and another pack has a normal
10900 argument or if one pack has an empty argument and an another
10901 one hasn't then tsubst_pack_expansion cannot perform the
10902 substitution and need to fall back on the
10903 PACK_EXPANSION_EXTRA mechanism. */
10911 {
10914 parm_pack;
10916 {
10921 /* We can't substitute a pack expansion with extra args into
10922 our pattern. */
10926 else
10928 }
10932 }
10934 }
10936 /* [temp.variadic]/6 says that:
10938 The instantiation of a pack expansion [...]
10939 produces a list E1,E2, ..., En, where N is the number of elements
10940 in the pack expansion parameters.
10942 This subroutine of tsubst_pack_expansion produces one of these Ei.
10944 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
10945 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
10946 PATTERN, and each TREE_VALUE is its corresponding argument pack.
10947 INDEX is the index 'i' of the element Ei to produce. ARGS,
10948 COMPLAIN, and IN_DECL are the same parameters as for the
10949 tsubst_pack_expansion function.
10951 The function returns the resulting Ei upon successful completion,
10952 or error_mark_node.
10954 Note that this function possibly modifies the ARGS parameter, so
10955 it's the responsibility of the caller to restore it. */
10957 static tree
10959 tree parm_packs,
10961 tree args /* This parm gets
10963 tsubst_flags_t complain,
10964 tree in_decl)
10965 {
10966 tree t;
10969 /* For each parameter pack, change the substitution of the parameter
10970 pack to the ith argument in its argument pack, then expand the
10971 pattern. */
10973 {
10978 ith_elem_is_expansion |=
10981 /* Select the Ith argument from the pack. */
10984 {
10986 {
10991 }
10992 else
10994 }
10995 else
10996 {
11001 {
11003 /* Update the corresponding argument. */
11005 }
11006 else
11007 /* Re-use the ARGUMENT_PACK_SELECT. */
11009 }
11011 }
11013 /* Substitute into the PATTERN with the (possibly altered)
11014 arguments. */
11016 /* Expanding a fixed parameter pack from
11017 coerce_template_parameter_pack. */
11022 {
11025 else
11028 }
11032 else
11035 /* If the Ith argument pack element is a pack expansion, then
11036 the Ith element resulting from the substituting is going to
11037 be a pack expansion as well. */
11042 }
11044 /* When the unexpanded parameter pack in a fold expression expands to an empty
11045 sequence, the value of the expression is as follows; the program is
11046 ill-formed if the operator is not listed in this table.
11048 && true
11049 || false
11050 , void() */
11052 tree
11054 {
11058 {
11067 }
11073 }
11075 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11076 form an expression that combines the two terms using the
11077 operator of T. */
11079 static tree
11081 {
11085 // Handle compound assignment operators.
11090 {
11100 complain);
11101 }
11102 }
11104 /* Substitute ARGS into the pack of a fold expression T. */
11108 {
11110 }
11112 /* Substitute ARGS into the pack of a fold expression T. */
11116 {
11118 }
11120 /* Expand a PACK of arguments into a grouped as left fold.
11121 Given a pack containing elements A0, A1, ..., An and an
11122 operator @, this builds the expression:
11124 ((A0 @ A1) @ A2) ... @ An
11126 Note that PACK must not be empty.
11128 The operator is defined by the original fold expression T. */
11130 static tree
11132 {
11135 {
11138 }
11140 }
11142 /* Substitute into a unary left fold expression. */
11144 static tree
11146 tree in_decl)
11147 {
11152 {
11156 }
11159 else
11161 }
11163 /* Substitute into a binary left fold expression.
11165 Do ths by building a single (non-empty) vector of argumnts and
11166 building the expression from those elements. */
11168 static tree
11170 tree in_decl)
11171 {
11180 {
11185 }
11193 }
11195 /* Expand a PACK of arguments into a grouped as right fold.
11196 Given a pack containing elementns A0, A1, ..., and an
11197 operator @, this builds the expression:
11199 A0@ ... (An-2 @ (An-1 @ An))
11201 Note that PACK must not be empty.
11203 The operator is defined by the original fold expression T. */
11205 tree
11207 {
11208 // Build the expression.
11212 {
11215 }
11217 }
11219 /* Substitute into a unary right fold expression. */
11221 static tree
11223 tree in_decl)
11224 {
11229 {
11233 }
11236 else
11238 }
11240 /* Substitute into a binary right fold expression.
11242 Do ths by building a single (non-empty) vector of arguments and
11243 building the expression from those elements. */
11245 static tree
11247 tree in_decl)
11248 {
11257 {
11262 }
11271 }
11274 /* Substitute ARGS into T, which is an pack expansion
11275 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
11276 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
11277 (if only a partial substitution could be performed) or
11278 ERROR_MARK_NODE if there was an error. */
11279 tree
11281 tree in_decl)
11282 {
11283 tree pattern;
11287 tree result;
11295 /* Add in any args remembered from an earlier partial instantiation. */
11300 /* Determine the argument packs that will instantiate the parameter
11301 packs used in the expansion expression. While we're at it,
11302 compute the number of arguments to be expanded and make sure it
11303 is consistent. */
11306 {
11313 {
11317 else
11320 }
11322 {
11323 /* We know we have correct local_specializations if this
11324 expansion is at function scope, or if we're dealing with a
11325 local parameter in a requires expression; for the latter,
11326 tsubst_requires_expr set it up appropriately. */
11329 else
11330 /* We can't rely on local_specializations for a parameter
11331 name used later in a function declaration (such as in a
11332 late-specified return type). Even if it exists, it might
11333 have the wrong value for a recursive call. */
11337 {
11338 /* This parameter pack was used in an unevaluated context. Just
11339 make a dummy decl, since it's only used for its type. */
11342 /* Partial instantiation of the parm_pack, we can't build
11343 up an argument pack yet. */
11345 else
11347 }
11348 }
11351 else
11352 {
11358 }
11365 /* This can only happen if we forget to expand an argument
11366 pack somewhere else. Just return an error, silently. */
11367 {
11371 }
11374 {
11378 /* Don't bother trying to do a partial substitution with
11379 incomplete packs; we'll try again after deduction. */
11386 {
11392 pattern);
11393 else
11396 pattern);
11398 }
11400 /* Keep track of the parameter packs and their corresponding
11401 argument packs. */
11404 }
11405 else
11406 {
11407 /* We can't substitute for this parameter pack. We use a flag as
11408 well as the missing_level counter because function parameter
11409 packs don't have a level. */
11412 }
11413 }
11415 /* If the expansion is just T..., return the matching argument pack, unless
11416 we need to call convert_from_reference on all the elements. This is an
11417 important optimization; see c++/68422. */
11420 {
11422 /* Types need no adjustment, nor does sizeof..., and if we still have
11423 some pack expansion args we won't do anything yet. */
11428 /* Also optimize expression pack expansions if we can tell that the
11429 elements won't have reference type. */
11435 /* Otherwise use the normal path so we get convert_from_reference. */
11436 }
11438 /* We cannot expand this expansion expression, because we don't have
11439 all of the argument packs we need. */
11441 {
11442 /* We got some full packs, but we can't substitute them in until we
11443 have values for all the packs. So remember these until then. */
11448 }
11450 {
11451 /* There were no real arguments, we're just replacing a parameter
11452 pack with another version of itself. Substitute into the
11453 pattern and return a PACK_EXPANSION_*. The caller will need to
11454 deal with that. */
11458 else
11462 }
11467 {
11468 /* We're in a late-specified return type, so create our own local
11469 specializations map; the current map is either NULL or (in the
11470 case of recursive unification) might have bindings that we don't
11471 want to use or alter. */
11474 }
11476 /* For each argument in each argument pack, substitute into the
11477 pattern. */
11481 {
11483 i,
11485 in_decl);
11488 {
11491 }
11492 }
11494 /* Update ARGS to restore the substitution from parameter packs to
11495 their argument packs. */
11497 {
11503 else
11504 {
11512 /* Update the corresponding argument. */
11516 else
11518 }
11519 }
11522 {
11525 }
11527 /* If the dependent pack arguments were such that we end up with only a
11528 single pack expansion again, there's no need to keep it in a TREE_VEC. */
11534 }
11536 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
11537 TMPL. We do this using DECL_PARM_INDEX, which should work even with
11538 parameter packs; all parms generated from a function parameter pack will
11539 have the same DECL_PARM_INDEX. */
11541 tree
11543 {
11545 tree patparm;
11548 {
11554 }
11555 else
11556 {
11561 }
11564 }
11566 /* Make an argument pack out of the TREE_VEC VEC. */
11568 static tree
11570 {
11571 tree pack;
11575 else
11576 {
11580 }
11583 }
11585 /* Return an exact copy of template args T that can be modified
11586 independently. */
11588 static tree
11590 {
11598 {
11603 }
11609 }
11611 /* Substitute ARGS into the vector or list of template arguments T. */
11613 static tree
11615 {
11627 {
11629 tree new_arg;
11634 {
11635 /* Substitute into an expansion expression. */
11639 /* Add to the expanded length adjustment the number of
11640 expanded arguments. We subtract one from this
11641 measurement, because the argument pack expression
11642 itself is already counted as 1 in
11643 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
11644 the argument pack is empty. */
11646 }
11648 {
11649 /* Substitute into each of the arguments. */
11655 new_arg,
11665 else
11672 }
11673 }
11674 else
11683 }
11688 /* Make space for the expanded arguments coming from template
11689 argument packs. */
11691 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
11692 arguments for a member template.
11693 In that case each TREE_VEC in ORIG_T represents a level of template
11694 arguments, and ORIG_T won't carry any non defaulted argument count.
11695 It will rather be the nested TREE_VECs that will carry one.
11696 In other words, ORIG_T carries a non defaulted argument count only
11697 if it doesn't contain any nested TREE_VEC. */
11699 {
11703 }
11705 {
11709 {
11712 /* Now expand the template argument pack "in place". */
11715 }
11716 else
11717 {
11719 out++;
11720 }
11721 }
11724 }
11726 /* Substitute ARGS into one level PARMS of template parameters. */
11728 static tree
11730 {
11737 {
11745 }
11748 }
11750 /* Return the result of substituting ARGS into the template parameters
11751 given by PARMS. If there are m levels of ARGS and m + n levels of
11752 PARMS, then the result will contain n levels of PARMS. For
11753 example, if PARMS is `template <class T> template <class U>
11754 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
11755 result will be `template <int*, double, class V>'. */
11757 static tree
11759 {
11763 /* When substituting into a template, we must set
11764 PROCESSING_TEMPLATE_DECL as the template parameters may be
11765 dependent if they are based on one-another, and the dependency
11766 predicates are short-circuit outside of templates. */
11773 {
11780 }
11785 }
11787 /* Return the result of substituting ARGS into one template parameter
11788 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
11789 parameter and which TREE_PURPOSE is the default argument of the
11790 template parameter. */
11792 static tree
11794 {
11815 }
11817 /* Substitute the ARGS into the indicated aggregate (or enumeration)
11818 type T. If T is not an aggregate or enumeration type, it is
11819 handled as if by tsubst. IN_DECL is as for tsubst. If
11820 ENTERING_SCOPE is nonzero, T is the context for a template which
11821 we are presently tsubst'ing. Return the substituted value. */
11823 static tree
11825 tree args,
11826 tsubst_flags_t complain,
11827 tree in_decl,
11829 {
11834 {
11839 /* Fall through. */
11843 {
11844 tree argvec;
11845 tree context;
11846 tree r;
11850 /* In "sizeof(X<I>)" we need to evaluate "I". */
11856 /* First, determine the context for the type we are looking
11857 up. */
11860 {
11863 /* If context is a nested class inside a class template,
11864 it may still need to be instantiated (c++/33959). */
11866 }
11868 /* Then, figure out what arguments are appropriate for the
11869 type we are trying to find. For example, given:
11871 template <class T> struct S;
11872 template <class T, class U> void f(T, U) { S<U> su; }
11874 and supposing that we are instantiating f<int, double>,
11875 then our ARGS will be {int, double}, but, when looking up
11876 S we only want {double}. */
11881 else
11882 {
11886 }
11892 }
11893 else
11894 /* This is not a template type, so there's nothing to do. */
11899 }
11900 }
11902 /* Substitute into the default argument ARG (a default argument for
11903 FN), which has the indicated TYPE. */
11905 tree
11907 {
11912 /* This can happen in invalid code. */
11916 /* This default argument came from a template. Instantiate the
11917 default argument here, not in tsubst. In the case of
11918 something like:
11920 template <class T>
11921 struct S {
11922 static T t();
11923 void f(T = t());
11924 };
11926 we must be careful to do name lookup in the scope of S<T>,
11927 rather than in the current class. */
11929 /* The "this" pointer is not valid in a default argument. */
11931 {
11936 }
11939 /* The default argument expression may cause implicitly defined
11940 member functions to be synthesized, which will result in garbage
11941 collection. We must treat this situation as if we were within
11942 the body of function so as to avoid collecting live data on the
11943 stack. */
11951 /* Restore the "this" pointer. */
11953 {
11956 }
11963 /* Make sure the default argument is reasonable. */
11969 }
11971 /* Substitute into all the default arguments for FN. */
11973 static void
11975 {
11976 tree arg;
11977 tree tmpl_args;
11981 /* If this function is not yet instantiated, we certainly don't need
11982 its default arguments. */
11985 /* Don't do this again for clones. */
11990 arg;
11996 complain);
11997 }
11999 /* Substitute the ARGS into the T, which is a _DECL. Return the
12000 result of the substitution. Issue error and warning messages under
12001 control of COMPLAIN. */
12003 static tree
12005 {
12006 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
12007 location_t saved_loc;
12012 /* Set the filename and linenumber to improve error-reporting. */
12017 {
12019 {
12020 /* We can get here when processing a member function template,
12021 member class template, or template template parameter. */
12023 tree spec;
12024 tree tmpl_args;
12025 tree full_args;
12028 {
12029 /* Template template parameter is treated here. */
12033 /* If we get a real template back, return it. This can happen in
12034 the context of most_specialized_partial_spec. */
12037 else
12038 /* The new TEMPLATE_DECL was built in
12039 reduce_template_parm_level. */
12042 }
12044 /* We might already have an instance of this template.
12045 The ARGS are for the surrounding class type, so the
12046 full args contain the tsubst'd args for the context,
12047 plus the innermost args from the template decl. */
12051 /* Because this is a template, the arguments will still be
12052 dependent, even after substitution. If
12053 PROCESSING_TEMPLATE_DECL is not set, the dependency
12054 predicates will short-circuit. */
12062 /* If this is a default template template argument,
12063 tsubst might not have changed anything. */
12070 {
12073 }
12075 /* Make a new template decl. It will be similar to the
12076 original, but will record the current template arguments.
12077 We also create a new function declaration, which is just
12078 like the old one, but points to this new template, rather
12079 than the old one. */
12084 // Build new template info linking to the original template decl.
12089 {
12090 tree new_type;
12098 /* For a partial specialization, we need to keep pointing to
12099 the primary template. */
12105 }
12106 else
12107 {
12108 tree new_decl;
12120 }
12126 /* The template parameters for this new template are all the
12127 template parameters for the old template, except the
12128 outermost level of parameters. */
12131 complain);
12137 /* Record this non-type partial instantiation. */
12141 }
12145 {
12146 tree ctx;
12149 tree gen_tmpl;
12150 tree type;
12155 /* Nobody should be tsubst'ing into non-template functions. */
12159 {
12160 tree spec;
12162 /* If T is not dependent, just return it. */
12166 /* Calculate the most general template of which R is a
12167 specialization, and the complete set of arguments used to
12168 specialize R. */
12171 (DECL_TEMPLATE_RESULT
12177 /* Check to see if we already have this specialization. */
12182 {
12185 }
12187 /* We can see more levels of arguments than parameters if
12188 there was a specialization of a member template, like
12189 this:
12191 template <class T> struct S { template <class U> void f(); }
12192 template <> template <class U> void S<int>::f(U);
12194 Here, we'll be substituting into the specialization,
12195 because that's where we can find the code we actually
12196 want to generate, but we'll have enough arguments for
12197 the most general template.
12199 We also deal with the peculiar case:
12201 template <class T> struct S {
12202 template <class U> friend void f();
12203 };
12204 template <class U> void f() {}
12205 template S<int>;
12206 template void f<double>();
12208 Here, the ARGS for the instantiation of will be {int,
12209 double}. But, we only need as many ARGS as there are
12210 levels of template parameters in CODE_PATTERN. We are
12211 careful not to get fooled into reducing the ARGS in
12212 situations like:
12214 template <class T> struct S { template <class U> void f(U); }
12215 template <class T> template <> void S<T>::f(int) {}
12217 which we can spot because the pattern will be a
12218 specialization in this case. */
12220 parms_depth =
12225 }
12226 else
12227 {
12228 /* This special case arises when we have something like this:
12230 template <class T> struct S {
12231 friend void f<int>(int, double);
12232 };
12234 Here, the DECL_TI_TEMPLATE for the friend declaration
12235 will be an IDENTIFIER_NODE. We are being called from
12236 tsubst_friend_function, and we want only to create a
12237 new decl (R) with appropriate types so that we can call
12238 determine_specialization. */
12240 }
12243 {
12246 else
12250 }
12251 else
12252 {
12255 }
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 /* If this is an instantiation of a function with internal
12311 linkage, we already know what object file linkage will be
12312 assigned to the instantiation. */
12321 /* We'll re-clone as appropriate in instantiate_template. */
12324 /* If we aren't complaining now, return on error before we register
12325 the specialization so that we'll complain eventually. */
12331 /* When instantiating a constrained member, substitute
12332 into the constraints to create a new constraint. */
12335 {
12338 }
12340 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
12341 this in the special friend case mentioned above where
12342 GEN_TMPL is NULL. */
12344 {
12349 tree new_r
12352 /* We instantiated this while substituting into
12353 the type earlier (template/friend54.C). */
12356 /* We're not supposed to instantiate default arguments
12357 until they are called, for a template. But, for a
12358 declaration like:
12360 template <class T> void f ()
12361 { extern void g(int i = T()); }
12363 we should do the substitution when the template is
12364 instantiated. We handle the member function case in
12365 instantiate_class_template since the default arguments
12366 might refer to other members of the class. */
12371 }
12372 else
12375 /* Copy the list of befriending classes. */
12379 {
12383 in_decl);
12384 }
12387 {
12391 /* If this is an instantiation of a member template, clone it.
12392 If it isn't, that'll be handled by
12393 clone_constructors_and_destructors. */
12396 }
12407 /* Possibly limit visibility based on template args. */
12410 {
12414 }
12422 }
12426 {
12434 {
12435 /* If there is a local specialization that isn't a
12436 parameter pack, it means that we're doing a "simple"
12437 substitution from inside tsubst_pack_expansion. Just
12438 return the local specialization (which will be a single
12439 parm). */
12446 /* Expand the TYPE_PACK_EXPANSION that provides the types for
12447 the parameters in this function parameter pack. */
12451 {
12454 /* Zero-length parameter packs are boring. Just substitute
12455 into the chain. */
12459 }
12460 else
12461 {
12462 /* All we did was update the type. Make a note of that. */
12465 }
12466 }
12468 /* Loop through all of the parameters we'll build. When T is
12469 a function parameter pack, LEN is the number of expanded
12470 types in EXPANDED_TYPES; otherwise, LEN is 1. */
12473 {
12480 /* We're on the Ith parameter of the function parameter
12481 pack. */
12482 {
12483 /* Get the Ith type. */
12486 /* Rename the parameter to include the index. */
12489 }
12491 /* We're dealing with a normal parameter. */
12499 {
12502 else
12505 }
12515 /* Keep track of the first new parameter we
12516 generate. That's what will be returned to the
12517 caller. */
12521 /* Build a proper chain of parameters when substituting
12522 into a function parameter pack. */
12525 }
12527 /* If cp_unevaluated_operand is set, we're just looking for a
12528 single dummy parameter, so don't keep going. */
12533 /* FIRST_R contains the start of the chain we've built. */
12535 }
12539 {
12546 {
12547 /* This field is a lambda capture pack. Return a TREE_VEC of
12548 the expanded fields to instantiate_class_template_1 and
12549 store them in the specializations hash table as a
12550 NONTYPE_ARGUMENT_PACK so that tsubst_copy can find them. */
12554 {
12557 }
12558 else
12559 {
12560 /* All we did was update the type. Make a note of that. */
12563 }
12564 }
12567 {
12570 {
12574 }
12584 /* For bit-fields, DECL_INITIAL gives the number of bits. For
12585 non-bit-fields DECL_INITIAL is a non-static data member
12586 initializer, which gets deferred instantiation. */
12592 {
12593 /* Set up DECL_TEMPLATE_INFO so that we can get at the
12594 NSDMI in perform_member_init. Still set DECL_INITIAL
12595 so that we know there is one. */
12600 }
12601 /* We don't have to set DECL_CONTEXT here; it is set by
12602 finish_member_declaration. */
12610 }
12613 {
12621 }
12622 }
12626 /* We reach here only for member using decls. We also need to check
12627 uses_template_parms because DECL_DEPENDENT_P is not set for a
12628 using-declaration that designates a member of the current
12629 instantiation (c++/53549). */
12632 {
12636 {
12641 {
12645 {
12648 }
12649 else
12650 {
12653 }
12655 }
12656 }
12657 else
12658 {
12664 else
12665 {
12668 }
12669 }
12670 }
12671 else
12672 {
12675 }
12680 {
12683 tree spec;
12685 tree ctx;
12694 {
12695 /* If this is the canonical decl, we don't have to
12696 mess with instantiations, and often we can't (for
12697 typename, template type parms and such). Note that
12698 TYPE_NAME is not correct for the above test if
12699 we've copied the type for a typedef. */
12705 }
12707 /* Check to see if we already have the specialization we
12708 need. */
12711 {
12712 /* T is a static data member or namespace-scope entity.
12713 We have to substitute into namespace-scope variables
12714 (not just variable templates) because of cases like:
12716 template <class T> void f() { extern T t; }
12718 where the entity referenced is not known until
12719 instantiation time. */
12723 {
12725 complain,
12727 /* If CTX is unchanged, then T is in fact the
12728 specialization we want. That situation occurs when
12729 referencing a static data member within in its own
12730 class. We can use pointer equality, rather than
12731 same_type_p, because DECL_CONTEXT is always
12732 canonical... */
12734 /* ... unless T is a member template; in which
12735 case our caller can be willing to create a
12736 specialization of that template represented
12737 by T. */
12741 }
12744 {
12749 argvec = (coerce_innermost_template_parms
12757 }
12758 }
12759 else
12760 {
12761 /* A local variable. */
12763 /* Subsequent calls to pushdecl will fill this in. */
12765 /* Unless this is a reference to a static variable from an
12766 enclosing function, in which case we need to fill it in now. */
12768 {
12772 }
12774 }
12775 /* If we already have the specialization we need, there is
12776 nothing more to do. */
12778 {
12781 }
12783 /* Create a new node for the specialization we need. */
12786 {
12789 else
12796 }
12798 {
12799 /* Even if the original location is out of scope, the
12800 newly substituted one is not. */
12807 {
12808 /* It may seem that this case cannot occur, since:
12810 typedef void f();
12811 void g() { f x; }
12813 declares a function, not a variable. However:
12815 typedef void f();
12816 template <typename T> void g() { T t; }
12817 template void g<f>();
12819 is an attempt to declare a variable with function
12820 type. */
12822 /* R is not yet sufficiently initialized, so we
12823 just use its name. */
12826 }
12828 /* Wait until cp_finish_decl to set this again, to handle
12829 circular dependency (template/instantiate6.C). */
12834 {
12839 {
12842 }
12844 }
12848 }
12854 /* Clear out the mangled name and RTL for the instantiation. */
12858 /* The initializer must not be expanded until it is required;
12859 see [temp.inst]. */
12867 {
12868 /* Possibly limit visibility based on template args. */
12871 {
12875 }
12877 }
12880 {
12881 /* A static data member declaration is always marked
12882 external when it is declared in-class, even if an
12883 initializer is present. We mimic the non-template
12884 processing here. */
12892 }
12893 else
12894 {
12899 }
12907 /* Preserve a typedef that names a type. */
12909 {
12913 /* An alias template specialization can be dependent
12914 even if its underlying type is not. */
12916 }
12919 }
12924 }
12925 #undef RETURN
12927 out:
12928 /* Restore the file and line information. */
12932 }
12934 /* Substitute into the ARG_TYPES of a function type.
12935 If END is a TREE_CHAIN, leave it and any following types
12936 un-substituted. */
12938 static tree
12940 tree args,
12941 tree end,
12942 tsubst_flags_t complain,
12943 tree in_decl)
12944 {
12945 tree remaining_arg_types;
12949 tree default_arg;
12960 {
12961 /* For a pack expansion, perform substitution on the
12962 entire expression. Later on, we'll handle the arguments
12963 one-by-one. */
12968 /* So that we'll spin through the parameters, one by one. */
12970 else
12971 {
12972 /* We only partially substituted into the parameter
12973 pack. Our type is TYPE_PACK_EXPANSION. */
12976 }
12977 }
12990 {
12992 {
12996 }
12998 }
12999 /* DR 657. */
13003 /* Do array-to-pointer, function-to-pointer conversion, and ignore
13004 top-level qualifiers as required. */
13007 /* We do not substitute into default arguments here. The standard
13008 mandates that they be instantiated only when needed, which is
13009 done in build_over_call. */
13013 {
13014 /* We've instantiated a template before its default arguments
13015 have been parsed. This can happen for a nested template
13016 class, and is not an error unless we require the default
13017 argument in a call of this function. */
13018 remaining_arg_types =
13021 }
13022 else
13023 remaining_arg_types =
13025 }
13028 }
13030 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
13031 *not* handle the exception-specification for FNTYPE, because the
13032 initial substitution of explicitly provided template parameters
13033 during argument deduction forbids substitution into the
13034 exception-specification:
13036 [temp.deduct]
13038 All references in the function type of the function template to the
13039 corresponding template parameters are replaced by the specified tem-
13040 plate argument values. If a substitution in a template parameter or
13041 in the function type of the function template results in an invalid
13042 type, type deduction fails. [Note: The equivalent substitution in
13043 exception specifications is done only when the function is instanti-
13044 ated, at which point a program is ill-formed if the substitution
13045 results in an invalid type.] */
13047 static tree
13049 tree args,
13050 tsubst_flags_t complain,
13051 tree in_decl)
13052 {
13053 tree return_type;
13055 tree fntype;
13057 /* The TYPE_CONTEXT is not used for function/method types. */
13060 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
13061 failure. */
13065 {
13066 /* Substitute the argument types. */
13078 {
13079 /* DR 1207: 'this' is in scope in the trailing return type. */
13081 }
13083 /* Substitute the return type. */
13087 {
13090 }
13091 }
13092 else
13093 /* Substitute the return type. */
13098 /* DR 486 clarifies that creation of a function type with an
13099 invalid return type is a deduction failure. */
13102 {
13104 {
13107 else
13109 }
13111 }
13112 /* And DR 657. */
13117 {
13118 /* Substitute the argument types. */
13123 }
13125 /* Construct a new type node and return it. */
13127 {
13132 }
13133 else
13134 {
13136 /* Don't pick up extra function qualifiers from the basetype. */
13139 {
13140 /* [temp.deduct]
13142 Type deduction may fail for any of the following
13143 reasons:
13145 -- Attempting to create "pointer to member of T" when T
13146 is not a class type. */
13149 r);
13151 }
13156 }
13163 }
13165 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
13166 ARGS into that specification, and return the substituted
13167 specification. If there is no specification, return NULL_TREE. */
13169 static tree
13171 tree args,
13172 tsubst_flags_t complain,
13173 tree in_decl,
13175 {
13176 tree specs;
13177 tree new_specs;
13182 {
13183 /* A noexcept-specifier. */
13188 {
13189 /* Defer instantiation of noexcept-specifiers to avoid
13190 excessive instantiations (c++/49107). */
13193 {
13194 /* We already partially instantiated this member template,
13195 so combine the new args with the old. */
13200 }
13201 else
13202 {
13205 }
13206 }
13207 else
13208 new_specs = tsubst_copy_and_build
13212 }
13214 {
13217 else
13219 {
13220 tree spec;
13225 {
13226 /* Expand the pack expansion type. */
13229 in_decl);
13235 else
13236 {
13237 /* We're substituting into a member template, so
13238 we got a TYPE_PACK_EXPANSION back. Add that
13239 expansion and move on. */
13243 expanded_specs,
13244 complain);
13247 }
13248 }
13251 {
13254 else
13259 complain);
13260 }
13263 }
13264 }
13266 }
13268 /* Take the tree structure T and replace template parameters used
13269 therein with the argument vector ARGS. IN_DECL is an associated
13270 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
13271 Issue error and warning messages under control of COMPLAIN. Note
13272 that we must be relatively non-tolerant of extensions here, in
13273 order to preserve conformance; if we allow substitutions that
13274 should not be allowed, we may allow argument deductions that should
13275 not succeed, and therefore report ambiguous overload situations
13276 where there are none. In theory, we could allow the substitution,
13277 but indicate that it should have failed, and allow our caller to
13278 make sure that the right thing happens, but we don't try to do this
13279 yet.
13281 This function is used for dealing with types, decls and the like;
13282 for expressions, use tsubst_expr or tsubst_copy. */
13284 tree
13286 {
13309 else
13314 /* Reuse typedefs. We need to do this to handle dependent attributes,
13315 such as attribute aligned. */
13318 {
13322 {
13323 /* DECL represents an alias template and we want to
13324 instantiate it. */
13328 }
13332 {
13336 }
13341 else
13342 /* The typedef is from a non-template context. */
13346 {
13348 r = cp_build_qualified_type_real
13352 }
13353 else
13354 {
13355 /* We don't have an instantiation yet, so drop the typedef. */
13360 }
13361 }
13377 {
13403 {
13409 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
13410 needed. */
13416 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
13417 with TREE_SIDE_EFFECTS that indicates this is not an integral
13418 constant expression. */
13421 {
13424 }
13427 }
13433 {
13439 /* Early in template argument deduction substitution, we don't
13440 want to reduce the level of 'auto', or it will be confused
13441 with a normal template parm in subsequent deduction. */
13453 {
13457 {
13458 /* See through ARGUMENT_PACK_SELECT arguments. */
13460 /* If the selected argument is an expansion E, that most
13461 likely means we were called from
13462 gen_elem_of_pack_expansion_instantiation during the
13463 substituting of pack an argument pack (which Ith
13464 element is a pack expansion, where I is
13465 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
13466 In this case, the Ith element resulting from this
13467 substituting is going to be a pack expansion, which
13468 pattern is the pattern of E. Let's return the
13469 pattern of E, and
13470 gen_elem_of_pack_expansion_instantiation will
13471 build the resulting pack expansion from it. */
13473 {
13474 /* Make sure we aren't throwing away arg info. */
13477 }
13478 }
13479 }
13484 {
13486 /* If ARG is an argument pack, we don't actually want to
13487 perform a substitution here, because substitutions
13488 for argument packs are only done
13489 element-by-element. We can get to this point when
13490 substituting the type of a non-type template
13491 parameter pack, when that type actually contains
13492 template parameter packs from an outer template, e.g.,
13494 template<typename... Types> struct A {
13495 template<Types... Values> struct B { };
13496 }; */
13500 {
13506 return cp_build_qualified_type_real
13508 }
13510 {
13511 /* We are processing a type constructed from a
13512 template template parameter. */
13523 /* Consider this code:
13525 template <template <class> class Template>
13526 struct Internal {
13527 template <class Arg> using Bind = Template<Arg>;
13528 };
13530 template <template <class> class Template, class Arg>
13531 using Instantiate = Template<Arg>; //#0
13533 template <template <class> class Template,
13534 class Argument>
13535 using Bind =
13536 Instantiate<Internal<Template>::template Bind,
13537 Argument>; //#1
13539 When #1 is parsed, the
13540 BOUND_TEMPLATE_TEMPLATE_PARM representing the
13541 parameter `Template' in #0 matches the
13542 UNBOUND_CLASS_TEMPLATE representing the argument
13543 `Internal<Template>::template Bind'; We then want
13544 to assemble the type `Bind<Argument>' that can't
13545 be fully created right now, because
13546 `Internal<Template>' not being complete, the Bind
13547 template cannot be looked up in that context. So
13548 we need to "store" `Bind<Argument>' for later
13549 when the context of Bind becomes complete. Let's
13550 store that in a TYPENAME_TYPE. */
13554 argvec),
13555 typename_type,
13556 complain);
13558 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
13559 are resolving nested-types in the signature of a
13560 member function templates. Otherwise ARG is a
13561 TEMPLATE_DECL and is the real template to be
13562 instantiated. */
13570 complain);
13571 return cp_build_qualified_type_real
13573 }
13576 else
13577 /* TEMPLATE_PARM_INDEX. */
13579 }
13582 /* This can happen during the attempted tsubst'ing in
13583 unify. This means that we don't yet have any information
13584 about the template parameter in question. */
13587 /* If we get here, we must have been looking at a parm for a
13588 more deeply nested template. Make a new version of this
13589 template parameter, but with a lower level. */
13591 {
13596 {
13598 r = cp_build_qualified_type_real
13602 }
13609 /* Break infinite recursion when substituting the constraints
13611 else
13612 {
13623 {
13624 /* Propagate constraints on placeholders. */
13629 {
13633 }
13634 }
13637 /* We have reduced the level of the template
13638 template parameter, but not the levels of its
13639 template parameters, so canonical_type_parameter
13640 will not be able to find the canonical template
13641 template parameter for this level. Thus, we
13642 require structural equality checking to compare
13643 TEMPLATE_TEMPLATE_PARMs. */
13647 else
13651 {
13653 /* We might need to substitute into the types of non-type
13654 template parameters. */
13666 }
13667 }
13676 }
13679 }
13682 {
13690 {
13694 }
13697 {
13701 }
13704 {
13708 }
13714 }
13717 /* We should never be tsubsting a binfo. */
13721 /* A vector of template arguments. */
13727 {
13731 /* [temp.deduct]
13733 Type deduction may fail for any of the following
13734 reasons:
13736 -- Attempting to create a pointer to reference type.
13737 -- Attempting to create a reference to a reference type or
13738 a reference to void.
13740 Core issue 106 says that creating a reference to a reference
13741 during instantiation is no longer a cause for failure. We
13742 only enforce this check in strict C++98 mode. */
13746 {
13749 /* We keep track of the last time we issued this error
13750 message to avoid spewing a ton of messages during a
13751 single bad template instantiation. */
13754 {
13759 else
13762 }
13765 }
13769 {
13771 {
13774 type);
13775 else
13777 type);
13778 }
13780 }
13782 {
13786 }
13788 /* In C++0x, during template argument substitution, when there is an
13789 attempt to create a reference to a reference type, reference
13790 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
13792 "If a template-argument for a template-parameter T names a type
13793 that is a reference to a type A, an attempt to create the type
13794 'lvalue reference to cv T' creates the type 'lvalue reference to
13795 A,' while an attempt to create the type type rvalue reference to
13796 cv T' creates the type T"
13797 */
13798 r = cp_build_reference_type
13801 else
13806 /* Will this ever be needed for TYPE_..._TO values? */
13810 }
13812 {
13815 {
13816 /* [temp.deduct]
13818 Type deduction may fail for any of the following
13819 reasons:
13821 -- Attempting to create "pointer to member of T" when T
13822 is not a class type. */
13826 }
13828 {
13832 }
13834 {
13838 }
13841 {
13842 /* The type of the implicit object parameter gets its
13843 cv-qualifiers from the FUNCTION_TYPE. */
13844 tree memptr;
13845 tree method_type
13850 complain);
13851 }
13852 else
13855 complain);
13856 }
13859 {
13860 tree fntype;
13861 tree specs;
13866 /* Substitute the exception specification. */
13874 }
13876 {
13881 /* As an optimization, we avoid regenerating the array type if
13882 it will obviously be the same as T. */
13886 /* These checks should match the ones in create_array_type_for_decl.
13888 [temp.deduct]
13890 The deduction may fail for any of the following reasons:
13892 -- Attempting to create an array with an element type that
13893 is void, a function type, or a reference type, or [DR337]
13894 an abstract class type. */
13900 {
13904 }
13912 {
13915 }
13918 }
13921 {
13933 {
13937 }
13939 {
13940 /* Normally, make_typename_type does not require that the CTX
13941 have complete type in order to allow things like:
13943 template <class T> struct S { typename S<T>::X Y; };
13945 But, such constructs have already been resolved by this
13946 point, so here CTX really should have complete type, unless
13947 it's a partial instantiation. */
13950 {
13954 }
13955 }
13962 {
13965 }
13968 {
13970 {
13974 else
13976 }
13978 {
13982 else
13984 }
13985 }
13987 return cp_build_qualified_type_real
13989 }
13992 {
14004 }
14007 {
14008 tree type;
14024 complain);
14025 }
14028 {
14029 tree type;
14040 {
14042 {
14046 }
14049 }
14060 else
14061 {
14065 /* In a template ~id could be either a complement expression
14066 or an unqualified-id naming a destructor; if instantiating
14067 it produces an expression, it's not an id-expression or
14068 member access. */
14071 }
14076 }
14079 {
14083 }
14087 {
14088 tree r;
14091 {
14093 /* Set the already-substituted type. */
14095 }
14096 else
14104 }
14119 /* We should use one of the expression tsubsts for these codes. */
14125 }
14126 }
14128 /* Like tsubst_expr for a BASELINK. OBJECT_TYPE, if non-NULL, is the
14129 type of the expression on the left-hand side of the "." or "->"
14130 operator. */
14132 static tree
14135 {
14136 tree name;
14137 tree qualifying_scope;
14138 tree fns;
14139 tree optype;
14144 /* A baselink indicates a function from a base class. Both the
14145 BASELINK_ACCESS_BINFO and the base class referenced may
14146 indicate bases of the template class, rather than the
14147 instantiated class. In addition, lookups that were not
14148 ambiguous before may be ambiguous now. Therefore, we perform
14149 the lookup again. */
14156 {
14163 }
14169 {
14171 {
14175 }
14177 }
14179 /* If lookup found a single function, mark it as used at this
14180 point. (If it lookup found multiple functions the one selected
14181 later by overload resolution will be marked as used at that
14182 point.) */
14189 /* Add back the template arguments, if present. */
14193 unknown_type_node,
14195 template_args);
14196 /* Update the conversion operator type. */
14204 {
14206 qualifying_scope,
14207 object_type);
14209 /* We need to call adjust_result_of_qualified_name_lookup in case the
14210 destructor names a base class, but we unset BASELINK_QUALIFIED_P
14211 so that we still get virtual function binding. */
14213 }
14215 }
14217 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
14218 true if the qualified-id will be a postfix-expression in-and-of
14219 itself; false if more of the postfix-expression follows the
14220 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
14221 of "&". */
14223 static tree
14227 {
14228 tree expr;
14229 tree scope;
14230 tree name;
14232 tree template_args;
14237 /* Figure out what name to look up. */
14240 {
14250 }
14251 else
14252 {
14255 }
14257 /* Substitute into the qualifying scope. When there are no ARGS, we
14258 are just trying to simplify a non-dependent expression. In that
14259 case the qualifying scope may be dependent, and, in any case,
14260 substituting will not help. */
14263 {
14266 }
14267 else
14271 {
14278 }
14281 {
14283 {
14284 /* A BIT_NOT_EXPR is used to represent a destructor. */
14286 {
14290 }
14291 else
14294 }
14295 else
14299 {
14301 {
14305 }
14307 }
14308 }
14311 {
14313 scope);
14314 /* Remember that there was a reference to this entity. */
14317 }
14320 {
14326 }
14329 {
14332 complain);
14333 else
14335 }
14341 {
14342 expr = (adjust_result_of_qualified_name_lookup
14344 expr = (finish_qualified_id_expr
14348 }
14350 /* Expressions do not generally have reference type. */
14352 /* However, if we're about to form a pointer-to-member, we just
14353 want the referenced member referenced. */
14361 }
14363 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
14364 initializer, DECL is the substituted VAR_DECL. Other arguments are as
14365 for tsubst. */
14367 static tree
14370 {
14377 {
14378 /* If we had an initializer but it
14379 instantiated to nothing,
14380 value-initialize the object. This will
14381 only occur when the initializer was a
14382 pack expansion where the parameter packs
14383 used in that expansion were of length
14384 zero. */
14386 complain);
14389 }
14392 }
14394 /* Like tsubst, but deals with expressions. This function just replaces
14395 template parms; to finish processing the resultant expression, use
14396 tsubst_copy_and_build or tsubst_expr. */
14398 static tree
14400 {
14402 tree r;
14410 {
14415 {
14416 /* We get here for a use of 'this' in an NSDMI as part of a
14417 constructor call or as part of an aggregate initialization. */
14419 && ((current_function_decl
14421 || (current_class_ref
14425 /* This can happen for a parameter name used later in a function
14426 declaration (such as in a late-specified return type). Just
14427 make a dummy decl, since it's only used for its type. */
14430 /* Give it the template pattern as its context; its true context
14431 hasn't been instantiated yet and this is good enough for
14432 mangling. */
14434 }
14443 {
14444 tree enum_type;
14445 tree v;
14449 /* There is no need to substitute into namespace-scope
14450 enumerators. */
14453 /* If ARGS is NULL, then T is known to be non-dependent. */
14457 /* Unfortunately, we cannot just call lookup_name here.
14458 Consider:
14460 template <int I> int f() {
14461 enum E { a = I };
14462 struct S { void g() { E e = a; } };
14463 };
14465 When we instantiate f<7>::S::g(), say, lookup_name is not
14466 clever enough to find f<7>::a. */
14467 enum_type
14477 /* We didn't find the name. That should never happen; if
14478 name-lookup found it during preliminary parsing, we
14479 should find it again here during instantiation. */
14481 }
14486 {
14487 /* Check for a local specialization set up by
14488 tsubst_pack_expansion. */
14490 {
14494 }
14496 /* When retrieving a capture pack from a generic lambda, remove the
14497 lambda call op's own template argument list from ARGS. Only the
14498 template arguments active for the closure type should be used to
14499 retrieve the pack specialization. */
14505 /* Otherwise return the full NONTYPE_ARGUMENT_PACK that
14506 tsubst_decl put in the hash table. */
14508 }
14511 {
14512 tree ctx;
14517 {
14520 {
14524 }
14526 }
14527 }
14537 {
14540 {
14541 /* First try name lookup to find the instantiation. */
14544 {
14545 /* Make sure that the one we found is the one we want. */
14551 }
14555 else
14556 {
14557 /* This can happen for a variable used in a
14558 late-specified return type of a local lambda, or for a
14559 local static or constant. Building a new VAR_DECL
14560 should be OK in all those cases. */
14563 {
14564 /* We can't call cp_finish_decl, so handle the
14565 initializer by hand. */
14576 }
14583 }
14584 /* Remember this for subsequent uses. */
14587 }
14588 }
14589 else
14599 /* An OVERLOAD will always be a non-dependent overload set; an
14600 overload set from function scope will just be represented with an
14601 IDENTIFIER_NODE, and from class scope with a BASELINK. */
14617 {
14618 /* Template template argument like the following example need
14619 special treatment:
14621 template <template <class> class TT> struct C {};
14622 template <class T> struct D {
14623 template <class U> struct E {};
14624 C<E> c; // #1
14625 };
14626 D<int> d; // #2
14628 We are processing the template argument `E' in #1 for
14629 the template instantiation #2. Originally, `E' is a
14630 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
14631 have to substitute this with one having context `D<int>'. */
14635 }
14636 else
14637 /* Ordinary template template argument. */
14648 {
14652 }
14657 {
14666 /* We only want to compute the number of arguments. */
14669 else
14676 {
14678 /* Set TREE_USED for the benefit of -Wunused. */
14682 }
14690 {
14695 else
14701 else
14704 }
14705 else
14707 }
14709 {
14717 }
14718 /* Fall through */
14734 {
14738 }
14741 {
14742 tree object;
14743 tree name;
14748 {
14752 }
14755 {
14765 }
14770 in_decl);
14771 else
14774 }
14812 {
14816 }
14819 {
14824 }
14827 {
14831 }
14834 {
14842 }
14848 {
14855 }
14858 {
14865 }
14868 {
14875 }
14878 {
14879 /* Substituted template arguments */
14888 }
14891 {
14911 }
14936 /* Fall through. */
14939 {
14942 }
14943 else
14947 /* This is handled by tsubst_copy_and_build. */
14951 {
14955 }
14958 /* We shouldn't have built any of these during initial template
14959 generation. Instead, they should be built during instantiation
14960 in response to the saved STMT_IS_FULL_EXPR_P setting. */
14964 {
14974 }
14992 {
14993 /* Instantiate any typedefs in the type. */
14998 }
15001 /* These can sometimes show up in a partial instantiation, but never
15002 involve template parms. */
15016 /* We shouldn't get here, but keep going if !flag_checking. */
15020 }
15021 }
15023 /* Helper function for tsubst_omp_clauses, used for instantiation of
15024 OMP_CLAUSE_DECL of clauses. */
15026 static tree
15028 tree in_decl)
15029 {
15033 /* Handle an OpenMP array section represented as a TREE_LIST (or
15034 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15035 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15036 TREE_LIST. We can handle it exactly the same as an array section
15037 (purpose, value, and a chain), even though the nomenclature
15038 (low_bound, length, etc) is different. */
15040 {
15041 tree low_bound
15047 in_decl);
15056 }
15059 /* Undo convert_from_reference tsubst_expr could have called. */
15065 }
15067 /* Like tsubst_copy, but specifically for OpenMP clauses. */
15069 static tree
15072 {
15077 {
15083 {
15086 {
15092 }
15093 /* FALLTHRU */
15108 in_decl);
15140 {
15143 {
15150 }
15151 else
15153 }
15156 in_decl);
15162 in_decl);
15170 in_decl);
15172 {
15175 }
15180 else
15183 in_decl,
15207 }
15210 {
15220 /* tsubst_expr on SCOPE_REF results in returning
15221 finish_non_static_data_member result. Undo that here. */
15225 {
15230 {
15234 CASE_CONVERT:
15243 /* FALLTHRU */
15247 }
15248 }
15254 {
15257 {
15261 }
15262 }
15266 }
15267 }
15271 {
15276 {
15279 }
15280 }
15282 }
15284 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
15286 static tree
15288 tree in_decl)
15289 {
15290 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
15310 {
15313 else
15314 {
15318 }
15319 }
15324 #undef RECUR
15325 }
15327 /* Used to temporarily communicate the list of #pragma omp parallel
15328 clauses to #pragma omp for instantiation if they are combined
15329 together. */
15333 /* Substitute one OMP_FOR iterator. */
15335 static void
15340 {
15341 #define RECUR(NODE) \
15342 tsubst_expr ((NODE), args, complain, in_decl, \
15343 integral_constant_expression_p)
15350 {
15353 }
15359 {
15360 /* We need to jump through some hoops to handle declarations in the
15361 init-statement, since we might need to handle auto deduction,
15362 but we need to keep control of initialization. */
15366 }
15367 else
15368 {
15370 {
15373 {
15377 {
15381 CASE_CONVERT:
15389 {
15392 }
15393 /* FALLTHRU */
15397 }
15398 }
15399 }
15400 else
15402 }
15413 {
15415 {
15416 /* Declare the variable, but don't let that initialize it. */
15421 }
15426 {
15431 }
15432 else
15439 }
15442 {
15443 /* Declare and initialize the variable. */
15446 }
15448 {
15452 {
15454 {
15460 {
15463 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
15468 }
15471 {
15473 decl);
15475 }
15478 {
15480 decl);
15482 }
15483 else
15485 }
15488 }
15490 {
15495 {
15498 }
15499 }
15500 }
15503 {
15507 }
15508 else
15512 {
15523 {
15531 }
15532 else
15538 {
15544 }
15548 {
15556 }
15557 else
15563 }
15569 #undef RECUR
15570 }
15572 /* Helper function of tsubst_expr, find OMP_TEAMS inside
15573 of OMP_TARGET's body. */
15575 static tree
15577 {
15580 {
15589 }
15591 }
15593 /* Helper function for tsubst_expr. For decomposition declaration
15594 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
15595 also the corresponding decls representing the identifiers
15596 of the decomposition declaration. Return DECL if successful
15597 or error_mark_node otherwise, set *FIRST to the first decl
15598 in the list chained through DECL_CHAIN and *CNT to the number
15599 of such decls. */
15601 static tree
15605 {
15610 decl2
15615 {
15617 {
15620 }
15636 {
15639 }
15640 else
15642 }
15645 }
15647 /* Like tsubst_copy for expressions, etc. but also does semantic
15648 processing. */
15650 tree
15653 {
15654 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
15655 #define RECUR(NODE) \
15656 tsubst_expr ((NODE), args, complain, in_decl, \
15657 integral_constant_expression_p)
15660 tree r;
15661 location_t loc;
15673 {
15675 {
15676 tree_stmt_iterator i;
15680 }
15695 else
15704 {
15706 tree init;
15712 {
15722 else
15724 }
15726 {
15727 /* Don't build up decls for a variadic capture proxy, we'll
15728 instantiate the elements directly as needed. */
15730 }
15731 else
15732 {
15736 {
15737 /* By marking the declaration as instantiated, we avoid
15738 trying to instantiate it. Since instantiate_decl can't
15739 handle local variables, and since we've already done
15740 all that needs to be done, that's the right thing to
15741 do. */
15746 /* Anonymous aggregates are a special case. */
15749 {
15752 {
15756 }
15758 }
15764 {
15769 }
15770 else
15771 {
15776 {
15777 /* For __PRETTY_FUNCTION__ we have to adjust the
15778 initializer. */
15782 }
15783 else
15787 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
15793 {
15795 tree first;
15801 }
15802 }
15803 }
15804 }
15807 }
15822 {
15830 {
15832 tree first;
15837 }
15838 else
15843 }
15869 else
15870 {
15877 }
15883 {
15892 }
15900 else
15908 else
15929 {
15936 }
15940 {
15942 tree label;
15949 }
15955 /* Computed goto's must be tsubst'd into. On the other hand,
15956 non-computed gotos must not be; the identifier in question
15957 will have no binding. */
15959 else
15965 {
15981 }
15986 {
15991 }
15992 else
15993 {
15998 else
16005 else
16011 else
16013 }
16017 {
16021 {
16023 /* Prevent instantiate_decl from trying to instantiate
16024 this variable. We've already done all that needs to be
16025 done. */
16028 }
16033 }
16039 {
16040 /* Local classes are not independent templates; they are
16041 instantiated along with their containing function. And this
16042 way we don't have to deal with pushing out of one local class
16043 to instantiate a member of another local class. */
16044 tree fn;
16045 /* Closures are handled by the LAMBDA_EXPR. */
16052 }
16056 {
16057 tree condition;
16060 condition =
16062 args,
16071 }
16077 in_decl);
16114 {
16129 in_decl);
16131 {
16138 }
16150 integral_constant_expression_p);
16161 else
16162 {
16170 }
16174 }
16179 /* FALLTHRU */
16186 in_decl);
16203 in_decl);
16214 {
16217 {
16218 /* For combined target teams, ensure the num_teams and
16219 thread_limit clause expressions are evaluated on the host,
16220 before entering the target construct. */
16221 tree c;
16227 {
16236 OMP_CLAUSE_FIRSTPRIVATE);
16240 }
16241 }
16242 }
16302 {
16307 {
16310 }
16316 }
16317 else
16318 {
16325 {
16328 }
16331 {
16336 {
16339 }
16345 }
16346 else
16347 {
16351 }
16354 }
16358 {
16364 {
16368 {
16373 }
16377 }
16378 else
16379 {
16384 }
16385 }
16389 {
16393 }
16413 /* If the first operand was a statement, we're done with it. */
16417 complain));
16429 integral_constant_expression_p));
16430 }
16433 out:
16436 #undef RECUR
16437 #undef RETURN
16438 }
16440 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
16441 function. For description of the body see comment above
16442 cp_parser_omp_declare_reduction_exprs. */
16444 static void
16446 {
16452 tree_stmt_iterator tsi;
16463 {
16482 }
16484 {
16504 }
16505 }
16507 /* T is a postfix-expression that is not being used in a function
16508 call. Return the substituted version of T. */
16510 static tree
16512 tsubst_flags_t complain,
16513 tree in_decl)
16514 {
16518 else
16524 }
16526 /* Like tsubst but deals with expressions and performs semantic
16527 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
16529 tree
16531 tree args,
16532 tsubst_flags_t complain,
16533 tree in_decl,
16536 {
16537 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
16538 #define RECUR(NODE) \
16539 tsubst_copy_and_build (NODE, args, complain, in_decl, \
16541 integral_constant_expression_p)
16544 location_t loc;
16553 /* N3276 decltype magic only applies to calls at the top level or on the
16554 right side of a comma. */
16559 {
16562 /* Fall through. */
16564 {
16565 tree decl;
16566 cp_id_kind idk;
16571 {
16574 }
16576 /* Look up the name. */
16579 /* By convention, expressions use ERROR_MARK_NODE to indicate
16580 failure, not NULL_TREE. */
16586 integral_constant_expression_p,
16594 input_location);
16598 {
16602 }
16604 }
16607 {
16608 tree object;
16621 {
16624 }
16625 else
16632 else
16634 }
16637 {
16641 {
16642 /* A type conversion to reference type will be enclosed in
16643 such an indirect ref, but the substitution of the cast
16644 will have also added such an indirect ref. */
16647 }
16648 else
16656 }
16659 {
16663 }
16666 {
16673 flags));
16674 }
16677 {
16681 }
16688 {
16689 tree type;
16695 {
16700 }
16706 {
16724 }
16727 }
16761 else
16763 in_decl);
16798 {
16805 tree r = build_x_binary_op
16807 op0,
16809 ? ERROR_MARK
16811 op1,
16813 ? ERROR_MARK
16821 }
16824 {
16828 }
16841 {
16850 }
16855 /* Fall through */
16858 {
16859 tree r;
16865 {
16866 /* When there are no ARGS, we are trying to evaluate a
16867 non-dependent expression from the parser. Trying to do
16868 the substitutions may not work. */
16871 }
16872 else
16873 {
16878 else
16881 /*integral_constant_expression_p=*/
16885 }
16889 else
16893 {
16895 {
16897 {
16901 }
16902 else
16906 }
16908 }
16910 }
16913 {
16923 }
16939 {
16943 tree r = build_x_modify_expr
16946 /* TREE_NO_WARNING must be set if either the expression was
16947 parenthesized or it uses an operator such as >>= rather
16948 than plain assignment. In the former case, it was already
16949 set and must be copied. In the latter case,
16950 build_x_modify_expr sets it and it must not be reset
16951 here. */
16956 }
16961 /* Remember that there was a reference to this entity. */
16968 {
16973 tree ret;
16977 else
16978 {
16982 }
16984 /* If there was an initializer in the original tree, but it
16985 instantiated to an empty list, then we should pass a
16986 non-NULL empty vector to tell build_new that it was an
16987 empty initializer() rather than no initializer. This can
16988 only happen when the initializer is a pack expansion whose
16989 parameter packs are of length zero. */
16992 else
16993 {
16997 else
16998 {
17001 }
17002 }
17008 complain);
17016 }
17019 {
17025 complain));
17026 }
17029 {
17033 integral_constant_expression_p);
17035 op0,
17038 }
17041 {
17042 tree function;
17047 tree ret;
17050 /* Internal function with no arguments. */
17054 /* When we parsed the expression, we determined whether or
17055 not Koenig lookup should be performed. */
17058 {
17061 }
17063 {
17068 }
17070 {
17071 /* Do nothing; calling tsubst_copy_and_build on an identifier
17072 would incorrectly perform unqualified lookup again.
17074 Note that we can also have an IDENTIFIER_NODE if the earlier
17075 unqualified lookup found a member function; in that case
17076 koenig_p will be false and we do want to do the lookup
17077 again to find the instantiated member function.
17079 FIXME but doing that causes c++/15272, so we need to stop
17080 using IDENTIFIER_NODE in that situation. */
17082 }
17083 else
17084 {
17086 {
17092 }
17093 else
17098 /* Avoid error about taking the address of a constructor. */
17102 in_decl,
17104 integral_constant_expression_p);
17108 }
17113 {
17118 else
17119 {
17120 /* Expand the pack expansion and push each entry onto
17121 CALL_ARGS. */
17124 {
17129 {
17134 }
17135 }
17136 else
17137 {
17138 /* A partial substitution. Add one entry. */
17140 }
17141 }
17142 }
17144 /* We do not perform argument-dependent lookup if normal
17145 lookup finds a non-function, in accordance with the
17146 expected resolution of DR 218. */
17149 /* If lookup found a member function, the Koenig lookup is
17150 not appropriate, even if an unqualified-name was used
17151 to denote the function. */
17154 /* Only do this when substitution turns a dependent call
17155 into a non-dependent call. */
17163 {
17165 {
17166 /* For backwards compatibility and good diagnostics, try
17167 the unqualified lookup again if we aren't in SFINAE
17168 context. */
17169 tree unq = (tsubst_copy_and_build
17171 integral_constant_expression_p));
17173 {
17176 }
17179 {
17180 /* In a lambda fn, we have to be careful to not
17181 introduce new this captures. Legacy code can't
17182 be using lambdas anyway, so it's ok to be
17183 stricter. */
17187 "and no declarations were found by "
17188 "argument-dependent lookup at the point "
17195 else
17199 {
17211 {
17213 input_location);
17215 "declarations in dependent base %qT are "
17221 else
17225 }
17226 else
17228 "%qD declared here, later in the "
17231 {
17234 }
17235 }
17238 }
17239 }
17241 {
17246 }
17247 }
17249 /* Remember that there was a reference to this entity. */
17253 {
17256 }
17258 /* Put back tf_decltype for the actual call. */
17263 {
17267 {
17269 "wrong number of arguments to "
17272 }
17273 else
17275 input_location),
17280 /* Unsupported internal function with arguments. */
17282 }
17285 complain);
17287 {
17302 complain);
17303 else
17304 ret = (build_new_method_call
17309 complain));
17310 }
17311 else
17314 koenig_p,
17315 complain);
17320 {
17326 {
17332 {
17334 /* The thunk location is not interesting. */
17336 }
17337 }
17338 }
17341 }
17344 {
17350 {
17352 {
17357 }
17358 else
17359 {
17364 }
17366 }
17367 else
17368 {
17371 }
17375 }
17378 {
17383 input_location));
17384 }
17387 {
17395 {
17396 /* We have pack expansions, so expand those and
17397 create a new list out of it. */
17400 tree chain;
17403 /* Expand the argument expressions. */
17411 /* Build the rest of the list. */
17416 /* Determine the number of arguments. */
17418 {
17421 }
17424 else
17425 {
17426 /* Since we only performed a partial substitution into
17427 the argument pack, we only RETURN (a single list
17428 node. */
17435 }
17437 /* Convert the argument vectors into a TREE_LIST */
17440 {
17441 /* Grab the Ith values. */
17442 i--;
17445 value
17449 /* Build the list (backwards). */
17451 }
17454 }
17470 }
17473 {
17474 tree object;
17475 tree object_type;
17476 tree member;
17477 tree r;
17481 /* Remember that there was a reference to this entity. */
17492 else
17498 {
17503 }
17507 {
17509 {
17514 {
17517 }
17519 {
17524 }
17525 }
17526 }
17529 {
17530 /* Lookup the template functions now that we know what the
17531 scope is. */
17539 {
17542 args);
17543 member = (adjust_result_of_qualified_name_lookup
17545 object_type));
17546 }
17547 else
17548 {
17550 input_location);
17552 }
17553 }
17557 {
17559 {
17563 else
17566 }
17568 }
17572 complain);
17576 }
17583 {
17591 tree r;
17596 /* digest_init will do the wrong thing if we let it. */
17600 /* We do not want to process the index of aggregate
17601 initializers as they are identifier nodes which will be
17602 looked up by digest_init. */
17608 {
17610 /* An identifier index is looked up in the type
17611 being initialized, not the current scope. */
17616 {
17617 /* Substitute into the pack expansion. */
17619 in_decl);
17623 ;
17625 /* Just move the argument into place. */
17627 else
17628 {
17629 /* Update the length of the final CONSTRUCTOR
17630 arguments vector, and note that we will need to
17631 copy.*/
17634 }
17635 }
17636 else
17638 }
17641 {
17646 {
17648 {
17653 }
17654 else
17656 }
17657 }
17667 }
17670 {
17673 {
17676 }
17677 else
17678 {
17681 }
17682 }
17688 {
17689 /* We don't build decls for an instantiation of a
17690 variadic capture proxy, we instantiate the elements
17691 when needed. */
17694 }
17695 /* Fall through */
17698 {
17700 /* ??? We're doing a subset of finish_id_expression here. */
17702 && !processing_template_decl
17703 && !cp_unevaluated_operand
17706 {
17708 /* Replace an evaluated use of the thread_local variable with
17709 a call to its wrapper. */
17711 }
17713 {
17717 }
17720 /* If the original type was a reference, we'll be wrapped in
17721 the appropriate INDIRECT_REF. */
17724 }
17727 {
17731 }
17734 {
17735 tree object_ptr
17742 }
17749 {
17760 }
17763 {
17769 integral_constant_expression_p);
17773 /* If the resulting list of expression statement is empty,
17774 fold it further into void_node. */
17779 }
17782 {
17800 /* For a function or variable scope, we want to use tsubst so that we
17801 don't complain about referring to an auto before deduction. */
17804 {
17805 /* Look up the parameter we want directly, as tsubst_copy
17806 doesn't do what we need. */
17812 /* FIXME Work around the parm not having DECL_CONTEXT set. */
17815 }
17817 /* For a field, use tsubst_copy so that we look up the existing field
17818 rather than build a new one. */
17820 else
17827 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
17829 /* Now that we know visibility, instantiate the type so we have a
17830 declaration of the op() for later calls to lambda_function. */
17841 }
17844 /* We can get here for a constant initializer of non-dependent type.
17845 FIXME stop folding in cp_parser_initializer_clause. */
17846 {
17848 complain);
17850 }
17854 integral_constant_expression_p));
17860 {
17865 complain));
17866 }
17872 /* Handle Objective-C++ constructs, if appropriate. */
17873 {
17874 tree subst
17879 }
17881 }
17883 #undef RECUR
17884 #undef RETURN
17885 out:
17888 }
17890 /* Verify that the instantiated ARGS are valid. For type arguments,
17891 make sure that the type's linkage is ok. For non-type arguments,
17892 make sure they are constants if they are integral or enumerations.
17893 Emit an error under control of COMPLAIN, and return TRUE on error. */
17895 static bool
17897 {
17901 {
17911 }
17913 {
17914 /* [basic.link]: A name with no linkage (notably, the name
17915 of a class or enumeration declared in a local scope)
17916 shall not be used to declare an entity with linkage.
17917 This implies that names with no linkage cannot be used as
17918 template arguments
17920 DR 757 relaxes this restriction for C++0x. */
17925 {
17926 /* DR 488 makes use of a type with no linkage cause
17927 type deduction to fail. */
17929 {
17932 else
17935 }
17937 }
17938 /* In order to avoid all sorts of complications, we do not
17939 allow variably-modified types as template arguments. */
17941 {
17945 }
17946 }
17947 /* Class template and alias template arguments should be OK. */
17949 ;
17950 /* A non-type argument of integral or enumerated type must be a
17951 constant. */
17956 {
17960 }
17962 }
17964 static bool
17966 {
17971 {
17974 }
17978 }
17980 /* We're out of SFINAE context now, so generate diagnostics for the access
17981 errors we saw earlier when instantiating D from TMPL and ARGS. */
17983 static void
17985 {
17997 }
17999 /* Instantiate the indicated variable, function, or alias template TMPL with
18000 the template arguments in TARG_PTR. */
18002 static tree
18004 {
18006 tree fndecl;
18007 tree gen_tmpl;
18008 tree spec;
18016 /* If this function is a clone, handle it specially. */
18018 {
18019 tree spec;
18020 tree clone;
18022 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
18023 DECL_CLONED_FUNCTION. */
18029 /* Look for the clone. */
18033 /* We should always have found the clone by now. */
18036 }
18041 /* Check to see if we already have this specialization. */
18045 /* targ_ptr only has the innermost template args, so add the outer ones
18046 from tmpl, which could be either a partial instantiation or gen_tmpl (in
18047 the case of a non-dependent call within a template definition). */
18048 targ_ptr = (add_outermost_template_args
18050 targ_ptr));
18052 /* It would be nice to avoid hashing here and then again in tsubst_decl,
18053 but it doesn't seem to be on the hot path. */
18062 {
18064 {
18068 }
18070 }
18073 complain))
18076 /* We are building a FUNCTION_DECL, during which the access of its
18077 parameters and return types have to be checked. However this
18078 FUNCTION_DECL which is the desired context for access checking
18079 is not built yet. We solve this chicken-and-egg problem by
18080 deferring all checks until we have the FUNCTION_DECL. */
18083 /* Instantiation of the function happens in the context of the function
18084 template, not the context of the overload resolution we're doing. */
18086 /* If there are dependent arguments, e.g. because we're doing partial
18087 ordering, make sure processing_template_decl stays set. */
18091 {
18095 }
18101 {
18102 /* We need to determine if we're using a partial or explicit
18103 specialization now, because the type of the variable could be
18104 different. */
18110 {
18115 }
18116 }
18118 /* Substitute template parameters to obtain the specialization. */
18126 {
18129 }
18131 /* The DECL_TI_TEMPLATE should always be the immediate parent
18132 template, not the most general template. */
18136 /* Now we know the specialization, compute access previously
18137 deferred. Do no access control for inheriting constructors,
18138 as we already checked access for the inherited constructor. */
18141 {
18146 }
18149 /* If we've just instantiated the main entry point for a function,
18150 instantiate all the alternate entry points as well. We do this
18151 by cloning the instantiation of the main entry point, not by
18152 instantiating the template clones. */
18157 {
18159 {
18160 /* Remember to reinstantiate when we're out of SFINAE so the user
18161 can see the errors. */
18163 }
18165 }
18167 }
18169 /* Wrapper for instantiate_template_1. */
18171 tree
18173 {
18174 tree ret;
18179 }
18181 /* Instantiate the alias template TMPL with ARGS. Also push a template
18182 instantiation level, which instantiate_template doesn't do because
18183 functions and variables have sufficient context established by the
18184 callers. */
18186 static tree
18188 {
18195 {
18198 }
18200 args =
18208 /* We can't free this if a pending_template entry or last_error_tinst_level
18209 is pointing at it. */
18215 }
18217 /* PARM is a template parameter pack for FN. Returns true iff
18218 PARM is used in a deducible way in the argument list of FN. */
18220 static bool
18222 {
18225 {
18227 tree packs;
18233 {
18234 /* The template parameter pack is used in a function parameter
18235 pack. If this is the end of the parameter list, the
18236 template parameter pack is deducible. */
18239 else
18240 /* Otherwise, not. Well, it could be deduced from
18241 a non-pack parameter, but doing so would end up with
18242 a deduction mismatch, so don't bother. */
18244 }
18245 }
18246 /* The template parameter pack isn't used in any function parameter
18247 packs, but it might be used deeper, e.g. tuple<Args...>. */
18249 }
18251 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
18252 NARGS elements of the arguments that are being used when calling
18253 it. TARGS is a vector into which the deduced template arguments
18254 are placed.
18256 Returns either a FUNCTION_DECL for the matching specialization of FN or
18257 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
18258 true, diagnostics will be printed to explain why it failed.
18260 If FN is a conversion operator, or we are trying to produce a specific
18261 specialization, RETURN_TYPE is the return type desired.
18263 The EXPLICIT_TARGS are explicit template arguments provided via a
18264 template-id.
18266 The parameter STRICT is one of:
18268 DEDUCE_CALL:
18269 We are deducing arguments for a function call, as in
18270 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
18271 deducing arguments for a call to the result of a conversion
18272 function template, as in [over.call.object].
18274 DEDUCE_CONV:
18275 We are deducing arguments for a conversion function, as in
18276 [temp.deduct.conv].
18278 DEDUCE_EXACT:
18279 We are deducing arguments when doing an explicit instantiation
18280 as in [temp.explicit], when determining an explicit specialization
18281 as in [temp.expl.spec], or when taking the address of a function
18282 template, as in [temp.deduct.funcaddr]. */
18284 tree
18286 tree explicit_targs,
18287 tree targs,
18290 tree return_type,
18291 unification_kind_t strict,
18295 {
18296 tree parms;
18297 tree fntype;
18310 tree tinst;
18316 full_targs = (add_outermost_template_args
18318 targs));
18323 /* In C++0x, it's possible to have a function template whose type depends
18324 on itself recursively. This is most obvious with decltype, but can also
18325 occur with enumeration scope (c++/48969). So we need to catch infinite
18326 recursion and reject the substitution at deduction time; this function
18327 will return error_mark_node for any repeated substitution.
18329 This also catches excessive recursion such as when f<N> depends on
18330 f<N-1> across all integers, and returns error_mark_node for all the
18331 substitutions back up to the initial one.
18333 This is, of course, not reentrant. */
18343 {
18344 /* [temp.deduct]
18346 The specified template arguments must match the template
18347 parameters in kind (i.e., type, nontype, template), and there
18348 must not be more arguments than there are parameters;
18349 otherwise type deduction fails.
18351 Nontype arguments must match the types of the corresponding
18352 nontype template parameters, or must be convertible to the
18353 types of the corresponding nontype parameters as specified in
18354 _temp.arg.nontype_, otherwise type deduction fails.
18356 All references in the function type of the function template
18357 to the corresponding template parameters are replaced by the
18358 specified template argument values. If a substitution in a
18359 template parameter or in the function type of the function
18360 template results in an invalid type, type deduction fails. */
18371 explicit_targs);
18373 /* Adjust any explicit template arguments before entering the
18374 substitution context. */
18375 explicit_targs
18377 complain,
18383 /* Substitute the explicit args into the function type. This is
18384 necessary so that, for instance, explicitly declared function
18385 arguments can match null pointed constants. If we were given
18386 an incomplete set of explicit args, we must not do semantic
18387 processing during substitution as we could create partial
18388 instantiations. */
18390 {
18395 /* Dig out the actual parm. */
18398 {
18401 }
18403 {
18406 }
18409 /* No explicit argument for this template parameter. */
18413 {
18414 /* Mark the argument pack as "incomplete". We could
18415 still deduce more arguments during unification.
18416 We remove this mark in type_unification_real. */
18418 {
18422 }
18424 /* We have some incomplete argument packs. */
18426 }
18427 }
18431 {
18434 }
18437 /* Ignore any access checks; we'll see them again in
18438 instantiate_template and they might have the wrong
18439 access path at this point. */
18451 /* Place the explicitly specified arguments in TARGS. */
18455 }
18457 /* Never do unification on the 'this' parameter. */
18461 {
18462 /* We're deducing for a call to the result of a template conversion
18463 function. The parms we really want are in return_type. */
18467 }
18469 {
18478 }
18480 /* We allow incomplete unification without an error message here
18481 because the standard doesn't seem to explicitly prohibit it. Our
18482 callers must be ready to deal with unification failures in any
18483 event. */
18486 /* If we aren't explaining yet, push tinst context so we can see where
18487 any errors (e.g. from class instantiations triggered by instantiation
18488 of default template arguments) come from. If we are explaining, this
18489 context is redundant. */
18491 {
18494 }
18496 /* type_unification_real will pass back any access checks from default
18497 template argument substitution. */
18509 /* Now that we have bindings for all of the template arguments,
18510 ensure that the arguments deduced for the template template
18511 parameters have compatible template parameter lists. We cannot
18512 check this property before we have deduced all template
18513 arguments, because the template parameter types of a template
18514 template parameter might depend on prior template parameters
18515 deduced after the template template parameter. The following
18516 ill-formed example illustrates this issue:
18518 template<typename T, template<T> class C> void f(C<5>, T);
18520 template<int N> struct X {};
18522 void g() {
18523 f(X<5>(), 5l); // error: template argument deduction fails
18524 }
18526 The template parameter list of 'C' depends on the template type
18527 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
18528 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
18529 time that we deduce 'C'. */
18532 {
18535 }
18537 /* All is well so far. Now, check:
18539 [temp.deduct]
18541 When all template arguments have been deduced, all uses of
18542 template parameters in nondeduced contexts are replaced with
18543 the corresponding deduced argument values. If the
18544 substitution results in an invalid type, as described above,
18545 type deduction fails. */
18548 {
18551 }
18553 /* Also collect access checks from the instantiation. */
18566 /* Now perform any access checks encountered during substitution. */
18573 /* If we're looking for an exact match, check that what we got
18574 is indeed an exact match. It might not be if some template
18575 parameters are used in non-deduced contexts. But don't check
18576 for an exact match if we have dependent template arguments;
18577 in that case we're doing partial ordering, and we already know
18578 that we have two candidates that will provide the actual type. */
18580 {
18584 tree sarg
18590 {
18594 }
18595 }
18597 /* After doing deduction with the inherited constructor, actually return an
18598 instantiation of the inheriting constructor. */
18604 fail:
18607 {
18609 /* Reset once we're all the way out. */
18611 }
18613 /* We can't free this if a pending_template entry or last_error_tinst_level
18614 is pointing at it. */
18620 }
18622 /* Adjust types before performing type deduction, as described in
18623 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
18624 sections are symmetric. PARM is the type of a function parameter
18625 or the return type of the conversion function. ARG is the type of
18626 the argument passed to the call, or the type of the value
18627 initialized with the result of the conversion function.
18628 ARG_EXPR is the original argument expression, which may be null. */
18630 static int
18634 tree arg_expr)
18635 {
18639 {
18644 /* Swap PARM and ARG throughout the remainder of this
18645 function; the handling is precisely symmetric since PARM
18646 will initialize ARG rather than vice versa. */
18651 /* Core issue #873: Do the DR606 thing (see below) for these cases,
18652 too, but here handle it by stripping the reference from PARM
18653 rather than by adding it to ARG. */
18661 /* Nothing else to do in this case. */
18666 }
18669 {
18670 /* [temp.deduct.call]
18672 If P is not a reference type:
18674 --If A is an array type, the pointer type produced by the
18675 array-to-pointer standard conversion (_conv.array_) is
18676 used in place of A for type deduction; otherwise,
18678 --If A is a function type, the pointer type produced by
18679 the function-to-pointer standard conversion
18680 (_conv.func_) is used in place of A for type deduction;
18681 otherwise,
18683 --If A is a cv-qualified type, the top level
18684 cv-qualifiers of A's type are ignored for type
18685 deduction. */
18690 else
18692 }
18694 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
18695 reference to a cv-unqualified template parameter that does not represent a
18696 template parameter of a class template (during class template argument
18697 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
18698 an lvalue, the type "lvalue reference to A" is used in place of A for type
18699 deduction. */
18706 /* try_one_overload doesn't provide an arg_expr, but
18707 functions are always lvalues. */
18711 /* [temp.deduct.call]
18713 If P is a cv-qualified type, the top level cv-qualifiers
18714 of P's type are ignored for type deduction. If P is a
18715 reference type, the type referred to by P is used for
18716 type deduction. */
18719 {
18722 }
18724 /* DR 322. For conversion deduction, remove a reference type on parm
18725 too (which has been swapped into ARG). */
18730 }
18732 /* Subroutine of unify_one_argument. PARM is a function parameter of a
18733 template which does contain any deducible template parameters; check if
18734 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
18735 unify_one_argument. */
18737 static int
18740 {
18741 tree type;
18745 else
18752 {
18756 }
18758 {
18763 }
18767 else
18769 }
18773 /* Returns true iff the expression EXPR is one from which a template
18774 argument can be deduced. In other words, if it's an undecorated
18775 use of a template non-type parameter. */
18777 static bool
18779 {
18780 /* Strip implicit conversions. */
18784 }
18786 /* Returns true iff the array domain DOMAIN uses a template parameter in a
18787 deducible way; that is, if it has a max value of <PARM> - 1. */
18789 static bool
18791 {
18800 }
18802 /* Returns true iff the template arguments ARGS use a template parameter
18803 in a deducible way. */
18805 static bool
18807 {
18809 {
18814 else
18815 {
18822 else
18824 }
18827 }
18829 }
18831 /* Returns true iff TYPE contains any deducible references to template
18832 parameters, as per 14.8.2.5. */
18834 static bool
18836 {
18840 /* T
18841 cv-list T
18842 TT<T>
18843 TT<i>
18844 TT<> */
18849 /* T*
18850 T&
18851 T&& */
18855 /* T[integer-constant ]
18856 type [i] */
18861 /* T type ::*
18862 type T::*
18863 T T::*
18864 T (type ::*)()
18865 type (T::*)()
18866 type (type ::*)(T)
18867 type (T::*)(T)
18868 T (type ::*)(T)
18869 T (T::*)()
18870 T (T::*)(T) */
18873 || (uses_deducible_template_parms
18876 /* template-name <T> (where template-name refers to a class template)
18877 template-name <i> (where template-name refers to a class template) */
18884 /* type (T)
18885 T()
18886 T(T) */
18889 {
18898 }
18901 }
18903 /* Subroutine of type_unification_real and unify_pack_expansion to
18904 handle unification of a single P/A pair. Parameters are as
18905 for those functions. */
18907 static int
18911 {
18918 /* We can't deduce anything from this, but we might get all the
18919 template args from other function args. */
18922 /* Implicit conversions (Clause 4) will be performed on a function
18923 argument to convert it to the type of the corresponding function
18924 parameter if the parameter type contains no template-parameters that
18925 participate in template argument deduction. */
18928 /* For function parameters with no deducible template parameters,
18929 just return. We'll check non-dependent conversions later. */
18933 {
18935 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
18936 | UNIFY_ALLOW_MORE_CV_QUAL
18950 }
18952 /* We only do these transformations if this is the top-level
18953 parameter_type_list in a call or declaration matching; in other
18954 situations (nested function declarators, template argument lists) we
18955 won't be comparing a type to an expression, and we don't do any type
18956 adjustments. */
18958 {
18960 {
18963 {
18964 /* [temp.deduct.type] A template-argument can be
18965 deduced from a pointer to function or pointer
18966 to member function argument if the set of
18967 overloaded functions does not contain function
18968 templates and at most one of a set of
18969 overloaded functions provides a unique
18970 match. */
18977 }
18983 }
18985 arg_strict |=
18987 }
18988 else
18993 /* For deduction from an init-list we need the actual list. */
18997 }
18999 /* for_each_template_parm callback that always returns 0. */
19001 static int
19003 {
19005 }
19007 /* for_each_template_parm any_fn callback to handle deduction of a template
19008 type argument from the type of an array bound. */
19010 static int
19012 {
19020 {
19026 }
19028 /* Keep walking. */
19030 }
19032 /* Try to deduce any not-yet-deduced template type arguments from the type of
19033 an array bound. This is handled separately from unify because 14.8.2.5 says
19034 "The type of a type parameter is only deduced from an array bound if it is
19035 not otherwise deduced." */
19037 static void
19039 {
19044 }
19046 /* Most parms like fn_type_unification.
19048 If SUBR is 1, we're being called recursively (to unify the
19049 arguments of a function or method parameter of a function
19050 template).
19052 CHECKS is a pointer to a vector of access checks encountered while
19053 substituting default template arguments. */
19055 static int
19057 tree full_targs,
19058 tree xparms,
19062 unification_kind_t strict,
19066 {
19071 tree parms;
19082 /* Reset the number of non-defaulted template arguments contained
19083 in TARGS. */
19086 again:
19094 {
19099 /* For a function parameter pack that occurs at the end of the
19100 parameter-declaration-list, the type A of each remaining
19101 argument of the call is compared with the type P of the
19102 declarator-id of the function parameter pack. */
19108 /* For a function parameter pack that does not occur at the
19109 end of the parameter-declaration-list, the type of the
19110 parameter pack is a non-deduced context. */
19117 explain_p))
19119 }
19124 {
19125 /* Unify the remaining arguments with the pack expansion type. */
19126 tree argvec;
19129 /* Allocate a TREE_VEC and copy in all of the arguments */
19134 /* Copy the parameter into parmvec. */
19140 /* Advance to the end of the list of parameters. */
19142 }
19144 /* Fail if we've reached the end of the parm list, and more args
19145 are present, and the parm list isn't variadic. */
19148 /* Fail if parms are left and they don't have default values and
19149 they aren't all deduced as empty packs (c++/57397). This is
19150 consistent with sufficient_parms_p. */
19153 {
19157 do
19158 {
19161 count++;
19163 }
19167 type_pack_p);
19168 }
19171 {
19172 tsubst_flags_t complain = (explain_p
19173 ? tf_warning_or_error
19178 {
19182 /* Clear the "incomplete" flags on all argument packs now so that
19183 substituting them into later default arguments works. */
19185 {
19188 }
19196 {
19201 }
19203 /* If this is an undeduced nontype parameter that depends on
19204 a type parameter, try another pass; its type may have been
19205 deduced from a later argument than the one from which
19206 this parameter can be deduced. */
19210 {
19213 }
19215 /* Core issue #226 (C++0x) [temp.deduct]:
19217 If a template argument has not been deduced, its
19218 default template argument, if any, is used.
19220 When we are in C++98 mode, TREE_PURPOSE will either
19221 be NULL_TREE or ERROR_MARK_NODE, so we do not need
19222 to explicitly check cxx_dialect here. */
19224 /* OK, there is a default argument. Wait until after the
19225 conversion check to do substitution. */
19228 /* If the type parameter is a parameter pack, then it will
19229 be deduced to an empty parameter pack. */
19231 {
19232 tree arg;
19235 {
19239 }
19240 else
19247 }
19250 }
19252 /* DR 1391: All parameters have args, now check non-dependent parms for
19253 convertibility. */
19257 {
19263 /* For a function parameter pack that occurs at the end of the
19264 parameter-declaration-list, the type A of each remaining
19265 argument of the call is compared with the type P of the
19266 declarator-id of the function parameter pack. */
19272 /* For a function parameter pack that does not occur at the
19273 end of the parameter-declaration-list, the type of the
19274 parameter pack is a non-deduced context. */
19283 explain_p))
19285 }
19287 /* Now substitute into the default template arguments. */
19289 {
19313 else
19321 {
19323 /* The position of the first default template argument,
19324 is also the number of non-defaulted arguments in TARGS.
19325 Record that. */
19328 }
19329 }
19333 }
19339 }
19341 /* Subroutine of type_unification_real. Args are like the variables
19342 at the call site. ARG is an overloaded function (or template-id);
19343 we try deducing template args from each of the overloads, and if
19344 only one succeeds, we go with that. Modifies TARGS and returns
19345 true on success. */
19347 static bool
19349 tree targs,
19350 tree parm,
19351 tree arg,
19352 unification_kind_t strict,
19355 {
19362 {
19365 }
19366 else
19370 /* Handle `&x' where `x' is some static or non-static member
19371 function name. */
19377 /* Strip baselink information. */
19382 {
19383 /* If we got some explicit template args, we need to plug them into
19384 the affected templates before we try to unify, in case the
19385 explicit args will completely resolve the templates in question. */
19392 {
19405 {
19410 {
19413 }
19414 }
19417 }
19418 /* If no templates (or more than one) are fully resolved by the
19419 explicit arguments, this template-id is a non-deduced context; it
19420 could still be OK if we deduce all template arguments for the
19421 enclosing call through other arguments. */
19424 }
19427 /* If ARG is, for example, "(0, &f)" then its type will be unknown
19428 -- but the deduction does not succeed because the expression is
19429 not just the function on its own. */
19431 else
19437 {
19440 }
19442 /* [temp.deduct.type] A template-argument can be deduced from a pointer
19443 to function or pointer to member function argument if the set of
19444 overloaded functions does not contain function templates and at most
19445 one of a set of overloaded functions provides a unique match.
19447 So if we found multiple possibilities, we return success but don't
19448 deduce anything. */
19451 {
19455 {
19460 /* Don't forget explicit template arguments in a pack. */
19464 }
19465 }
19470 }
19472 /* Core DR 115: In contexts where deduction is done and fails, or in
19473 contexts where deduction is not done, if a template argument list is
19474 specified and it, along with any default template arguments, identifies
19475 a single function template specialization, then the template-id is an
19476 lvalue for the function template specialization. */
19478 tree
19480 {
19493 {
19496 }
19498 {
19501 }
19503 {
19506 }
19509 {
19513 /* If we got some explicit template args, we need to plug them into
19514 the affected templates before we try to unify, in case the
19515 explicit args will completely resolve the templates in question. */
19523 {
19536 {
19539 {
19542 }
19544 {
19547 }
19548 }
19549 }
19551 {
19559 {
19560 tree base
19563 }
19567 }
19569 /* There were no good options and at least one bad one, so let the
19570 user know what the problem is. */
19572 }
19574 }
19576 /* Subroutine of resolve_overloaded_unification; does deduction for a single
19577 overload. Fills TARGS with any deduced arguments, or error_mark_node if
19578 different overloads deduce different arguments for a given parm.
19579 ADDR_P is true if the expression for which deduction is being
19580 performed was of the form "& fn" rather than simply "fn".
19582 Returns 1 on success. */
19584 static int
19586 tree orig_targs,
19587 tree targs,
19588 tree parm,
19589 tree arg,
19590 unification_kind_t strict,
19594 {
19596 tree tempargs;
19602 /* [temp.deduct.type] A template-argument can be deduced from a pointer
19603 to function or pointer to member function argument if the set of
19604 overloaded functions does not contain function templates and at most
19605 one of a set of overloaded functions provides a unique match.
19607 So if this is a template, just return success. */
19619 /* We don't copy orig_targs for this because if we have already deduced
19620 some template args from previous args, unify would complain when we
19621 try to deduce a template parameter for the same argument, even though
19622 there isn't really a conflict. */
19629 /* First make sure we didn't deduce anything that conflicts with
19630 explicitly specified args. */
19632 {
19639 /* Since we're unifying against ourselves, we will fill in
19640 template args used in the function parm list with our own
19641 template parms. Discard them. */
19644 {
19645 /* Check that the argument at each index of the deduced argument pack
19646 is equivalent to the corresponding explicitly specified argument.
19647 We may have deduced more arguments than were explicitly specified,
19648 and that's OK. */
19664 }
19667 }
19670 {
19675 }
19678 }
19680 /* PARM is a template class (perhaps with unbound template
19681 parameters). ARG is a fully instantiated type. If ARG can be
19682 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
19683 TARGS are as for unify. */
19685 static tree
19688 {
19689 tree copy_of_targs;
19699 /* We need to make a new template argument vector for the call to
19700 unify. If we used TARGS, we'd clutter it up with the result of
19701 the attempted unification, even if this class didn't work out.
19702 We also don't want to commit ourselves to all the unifications
19703 we've already done, since unification is supposed to be done on
19704 an argument-by-argument basis. In other words, consider the
19705 following pathological case:
19707 template <int I, int J, int K>
19708 struct S {};
19710 template <int I, int J>
19711 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
19713 template <int I, int J, int K>
19714 void f(S<I, J, K>, S<I, I, I>);
19716 void g() {
19717 S<0, 0, 0> s0;
19718 S<0, 1, 2> s2;
19720 f(s0, s2);
19721 }
19723 Now, by the time we consider the unification involving `s2', we
19724 already know that we must have `f<0, 0, 0>'. But, even though
19725 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
19726 because there are two ways to unify base classes of S<0, 1, 2>
19727 with S<I, I, I>. If we kept the already deduced knowledge, we
19728 would reject the possibility I=1. */
19732 {
19736 }
19738 /* If unification failed, we're done. */
19744 }
19746 /* Given a template type PARM and a class type ARG, find the unique
19747 base type in ARG that is an instance of PARM. We do not examine
19748 ARG itself; only its base-classes. If there is not exactly one
19749 appropriate base class, return NULL_TREE. PARM may be the type of
19750 a partial specialization, as well as a plain template type. Used
19751 by unify. */
19753 static enum template_base_result
19756 {
19758 tree binfo;
19764 {
19765 /* The type could not be completed. */
19768 }
19770 /* Walk in inheritance graph order. The search order is not
19771 important, and this avoids multiple walks of virtual bases. */
19773 {
19778 {
19779 /* If there is more than one satisfactory baseclass, then:
19781 [temp.deduct.call]
19783 If they yield more than one possible deduced A, the type
19784 deduction fails.
19786 applies. */
19788 {
19791 }
19794 }
19795 }
19799 }
19801 /* Returns the level of DECL, which declares a template parameter. */
19803 static int
19805 {
19807 {
19817 }
19819 }
19821 /* Decide whether ARG can be unified with PARM, considering only the
19822 cv-qualifiers of each type, given STRICT as documented for unify.
19823 Returns nonzero iff the unification is OK on that basis. */
19825 static int
19827 {
19833 {
19834 /* Although a CVR qualifier is ignored when being applied to a
19835 substituted template parameter ([8.3.2]/1 for example), that
19836 does not allow us to unify "const T" with "int&" because both
19837 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
19838 It is ok when we're allowing additional CV qualifiers
19839 at the outer level [14.8.2.1]/3,1st bullet. */
19849 }
19860 }
19862 /* Determines the LEVEL and INDEX for the template parameter PARM. */
19863 void
19865 {
19869 {
19872 }
19873 else
19874 {
19877 }
19878 }
19880 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
19881 do { \
19882 if (unify (TP, TA, P, A, S, EP)) \
19883 return 1; \
19884 } while (0)
19886 /* Unifies the remaining arguments in PACKED_ARGS with the pack
19887 expansion at the end of PACKED_PARMS. Returns 0 if the type
19888 deduction succeeds, 1 otherwise. STRICT is the same as in
19889 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
19890 function call argument list. We'll need to adjust the arguments to make them
19891 types. SUBR tells us if this is from a recursive call to
19892 type_unification_real, or for comparing two template argument
19893 lists. */
19895 static int
19899 {
19900 tree parm
19910 /* Determine the parameter packs we will be deducing from the
19911 pattern, and record their current deductions. */
19914 {
19918 /* Determine the index and level of this parameter pack. */
19921 /* Keep track of the parameter packs and their corresponding
19922 argument packs. */
19925 }
19927 /* Loop through all of the arguments that have not yet been
19928 unified and unify each with the pattern. */
19930 {
19931 tree parm;
19935 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
19936 or the element of its argument pack at the current index if
19937 this argument was explicitly specified. */
19939 {
19948 {
19951 }
19953 }
19955 /* If we had explicit template arguments, substitute them into the
19956 pattern before deduction. */
19958 {
19959 /* Some arguments might still be unspecified or dependent. */
19967 NULL_TREE);
19972 }
19973 else
19976 /* Unify the pattern with the current argument. */
19978 explain_p))
19981 /* For each parameter pack, collect the deduced value. */
19983 {
19989 }
19990 }
19992 /* Verify that the results of unification with the parameter packs
19993 produce results consistent with what we've seen before, and make
19994 the deduced argument packs available. */
19996 {
20003 /* By default keep the original deduced argument pack.
20004 If necessary, more specific code is going to update the
20005 resulting deduced argument later down in this function. */
20009 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
20010 actually deduce anything. */
20018 {
20019 /* If we had fewer function args than explicit template args,
20020 just use the explicits. */
20025 }
20028 {
20029 tree result;
20030 /* Build the deduced *_ARGUMENT_PACK. */
20032 {
20037 }
20038 else
20043 /* Note the deduced argument packs for this parameter
20044 pack. */
20046 }
20050 {
20051 /* We only had the explicitly-provided arguments before, but
20052 now we have a complete set of arguments. */
20058 }
20059 else
20060 {
20066 /* Inconsistent unification of this parameter pack. */
20068 bad_old_arg,
20069 bad_new_arg);
20070 }
20071 }
20074 }
20076 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
20077 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
20078 parameters and return value are as for unify. */
20080 static int
20084 {
20085 tree parm_max;
20086 tree arg_max;
20090 /* Our representation of array types uses "N - 1" as the
20091 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
20092 not an integer constant. We cannot unify arbitrarily
20093 complex expressions, so we eliminate the MINUS_EXPRs
20094 here. */
20098 {
20101 }
20105 {
20106 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
20107 trying to unify the type of a variable with the type
20108 of a template parameter. For example:
20110 template <unsigned int N>
20111 void f (char (&) [N]);
20112 int g();
20113 void h(int i) {
20114 char a[g(i)];
20115 f(a);
20116 }
20118 Here, the type of the ARG will be "int [g(i)]", and
20119 may be a SAVE_EXPR, etc. */
20123 }
20125 /* If only one of the bounds used a MINUS_EXPR, compensate
20126 by adding one to the other bound. */
20129 integer_type_node,
20130 parm_max,
20131 integer_one_node);
20134 integer_type_node,
20135 arg_max,
20136 integer_one_node);
20140 }
20142 /* Returns whether T, a P or A in unify, is a type, template or expression. */
20146 static pa_kind_t
20148 {
20157 else
20159 }
20161 /* Deduce the value of template parameters. TPARMS is the (innermost)
20162 set of template parameters to a template. TARGS is the bindings
20163 for those template parameters, as determined thus far; TARGS may
20164 include template arguments for outer levels of template parameters
20165 as well. PARM is a parameter to a template function, or a
20166 subcomponent of that parameter; ARG is the corresponding argument.
20167 This function attempts to match PARM with ARG in a manner
20168 consistent with the existing assignments in TARGS. If more values
20169 are deduced, then TARGS is updated.
20171 Returns 0 if the type deduction succeeds, 1 otherwise. The
20172 parameter STRICT is a bitwise or of the following flags:
20174 UNIFY_ALLOW_NONE:
20175 Require an exact match between PARM and ARG.
20176 UNIFY_ALLOW_MORE_CV_QUAL:
20177 Allow the deduced ARG to be more cv-qualified (by qualification
20178 conversion) than ARG.
20179 UNIFY_ALLOW_LESS_CV_QUAL:
20180 Allow the deduced ARG to be less cv-qualified than ARG.
20181 UNIFY_ALLOW_DERIVED:
20182 Allow the deduced ARG to be a template base class of ARG,
20183 or a pointer to a template base class of the type pointed to by
20184 ARG.
20185 UNIFY_ALLOW_INTEGER:
20186 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
20187 case for more information.
20188 UNIFY_ALLOW_OUTER_LEVEL:
20189 This is the outermost level of a deduction. Used to determine validity
20190 of qualification conversions. A valid qualification conversion must
20191 have const qualified pointers leading up to the inner type which
20192 requires additional CV quals, except at the outer level, where const
20193 is not required [conv.qual]. It would be normal to set this flag in
20194 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
20195 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
20196 This is the outermost level of a deduction, and PARM can be more CV
20197 qualified at this point.
20198 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
20199 This is the outermost level of a deduction, and PARM can be less CV
20200 qualified at this point. */
20202 static int
20205 {
20207 tree targ;
20208 tree tparm;
20210 tsubst_flags_t complain = (explain_p
20211 ? tf_warning_or_error
20214 /* I don't think this will do the right thing with respect to types.
20215 But the only case I've seen it in so far has been array bounds, where
20216 signedness is the only information lost, and I think that will be
20217 okay. */
20225 /* We can't deduce anything from this, but we might get all the
20226 template args from other function args. */
20232 /* If PARM uses template parameters, then we can't bail out here,
20233 even if ARG == PARM, since we won't record unifications for the
20234 template parameters. We might need them if we're trying to
20235 figure out which of two things is more specialized. */
20239 /* Handle init lists early, so the rest of the function can assume
20240 we're dealing with a type. */
20242 {
20247 /* Replace T with std::initializer_list<T> for deduction. */
20254 /* We can only deduce from an initializer list argument if the
20255 parameter is std::initializer_list or an array; otherwise this
20256 is a non-deduced context. */
20261 else
20262 {
20264 /* Deduction is defined in terms of a single type, so just punt
20265 on the (bizarre) std::initializer_list<T...>. */
20268 }
20271 {
20278 {
20282 /* It should only be possible to get here for a call. */
20284 elt_strict |= maybe_adjust_types_for_deduction
20287 }
20290 explain_p);
20291 }
20295 {
20296 /* Also deduce from the length of the initializer list. */
20303 }
20305 /* If the std::initializer_list<T> deduction worked, replace the
20306 deduced A with std::initializer_list<A>. */
20308 {
20313 }
20315 }
20317 /* If parm and arg aren't the same kind of thing (template, type, or
20318 expression), fail early. */
20322 /* Immediately reject some pairs that won't unify because of
20323 cv-qualification mismatches. */
20326 /* It is the elements of the array which hold the cv quals of an array
20327 type, and the elements might be template type parms. We'll check
20328 when we recurse. */
20330 /* We check the cv-qualifiers when unifying with template type
20331 parameters below. We want to allow ARG `const T' to unify with
20332 PARM `T' for example, when computing which of two templates
20333 is more specialized, for example. */
20347 {
20351 /* In a type which contains a nested-name-specifier, template
20352 argument values cannot be deduced for template parameters used
20353 within the nested-name-specifier. */
20365 /* The PARM is not one we're trying to unify. Just check
20366 to see if it matches ARG. */
20367 {
20372 else
20374 }
20381 /* Check for mixed types and values. */
20389 {
20392 {
20393 /* First try to match ARG directly. */
20395 explain_p);
20397 {
20398 /* Otherwise, look for a suitable base of ARG, as below. */
20405 }
20406 }
20407 /* ARG must be constructed from a template class or a template
20408 template parameter. */
20413 /* Deduce arguments T, i from TT<T> or TT<i>. */
20419 /* Fall through to deduce template name. */
20420 }
20424 {
20425 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
20427 /* Simple cases: Value already set, does match or doesn't. */
20432 }
20433 else
20434 {
20435 /* If PARM is `const T' and ARG is only `int', we don't have
20436 a match unless we are allowing additional qualification.
20437 If ARG is `const int' and PARM is just `T' that's OK;
20438 that binds `const int' to `T'. */
20443 /* Consider the case where ARG is `const volatile int' and
20444 PARM is `const T'. Then, T should be `volatile int'. */
20445 arg = cp_build_qualified_type_real
20450 /* Simple cases: Value already set, does match or doesn't. */
20456 /* Make sure that ARG is not a variable-sized array. (Note
20457 that were talking about variable-sized arrays (like
20458 `int[n]'), rather than arrays of unknown size (like
20459 `int[]').) We'll get very confused by such a type since
20460 the bound of the array is not constant, and therefore
20461 not mangleable. Besides, such types are not allowed in
20462 ISO C++, so we can do as we please here. We do allow
20463 them for 'auto' deduction, since that isn't ABI-exposed. */
20467 /* Strip typedefs as in convert_template_argument. */
20469 }
20471 /* If ARG is a parameter pack or an expansion, we cannot unify
20472 against it unless PARM is also a parameter pack. */
20477 /* If the argument deduction results is a METHOD_TYPE,
20478 then there is a problem.
20479 METHOD_TYPE doesn't map to any real C++ type the result of
20480 the deduction can not be of that type. */
20494 {
20495 /* The PARM is not one we're trying to unify. Just check
20496 to see if it matches ARG. */
20502 }
20508 {
20513 }
20516 /* We deduce from array bounds in try_array_deduction. */
20520 {
20525 }
20527 /* [temp.deduct.type] If, in the declaration of a function template
20528 with a non-type template-parameter, the non-type
20529 template-parameter is used in an expression in the function
20530 parameter-list and, if the corresponding template-argument is
20531 deduced, the template-argument type shall match the type of the
20532 template-parameter exactly, except that a template-argument
20533 deduced from an array bound may be of any integral type.
20534 The non-type parameter might use already deduced type parameters. */
20537 {
20541 }
20544 /* Template-parameter dependent expression. Just accept it for now.
20545 It will later be processed in convert_template_argument. */
20546 ;
20551 /* Convert the ARG to the type of PARM; the deduced non-type
20552 template argument must exactly match the types of the
20553 corresponding parameter. */
20556 /* We haven't deduced the type of this parameter yet. Try again
20557 later. */
20559 else
20562 /* If ARG is a parameter pack or an expansion, we cannot unify
20563 against it unless PARM is also a parameter pack. */
20568 {
20571 }
20576 {
20577 /* A pointer-to-member constant can be unified only with
20578 another constant. */
20582 /* Just unify the class member. It would be useless (and possibly
20583 wrong, depending on the strict flags) to unify also
20584 PTRMEM_CST_CLASS, because we want to be sure that both parm and
20585 arg refer to the same variable, even if through different
20586 classes. For instance:
20588 struct A { int x; };
20589 struct B : A { };
20591 Unification of &A::x and &B::x must succeed. */
20594 }
20597 {
20601 /* [temp.deduct.call]
20603 A can be another pointer or pointer to member type that can
20604 be converted to the deduced A via a qualification
20605 conversion (_conv.qual_).
20607 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
20608 This will allow for additional cv-qualification of the
20609 pointed-to types if appropriate. */
20612 /* The derived-to-base conversion only persists through one
20613 level of pointers. */
20618 }
20650 /* We have already checked cv-qualification at the top of the
20651 function. */
20655 /* As far as unification is concerned, this wins. Later checks
20656 will invalidate it if necessary. */
20659 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
20660 /* Type INTEGER_CST can come from ordinary constant template args. */
20672 {
20682 /* Check for pack expansions in the parameters. */
20684 {
20686 {
20688 /* We can unify against something with a trailing
20689 parameter pack. */
20691 else
20692 /* [temp.deduct.type]/9: If the template argument list of
20693 P contains a pack expansion that is not the last
20694 template argument, the entire template argument list
20695 is a non-deduced context. */
20697 }
20698 }
20700 /* If we don't have enough arguments to satisfy the parameters
20701 (not counting the pack expression at the end), or we have
20702 too many arguments for a parameter list that doesn't end in
20703 a pack expression, we can't unify. */
20709 /* Unify all of the parameters that precede the (optional)
20710 pack expression. */
20712 {
20717 }
20720 DEDUCE_EXACT,
20723 }
20731 {
20739 }
20744 {
20748 {
20749 /* First, we try to unify the PARM and ARG directly. */
20754 {
20755 /* Fallback to the special case allowed in
20756 [temp.deduct.call]:
20758 If P is a class, and P has the form
20759 template-id, then A can be a derived class of
20760 the deduced A. Likewise, if P is a pointer to
20761 a class of the form template-id, A can be a
20762 pointer to a derived class pointed to by the
20763 deduced A. */
20769 {
20770 /* Don't give the derived diagnostic if we're
20771 already dealing with the same template. */
20772 bool same_template
20778 }
20779 }
20780 }
20784 /* Perhaps PARM is something like S<U> and ARG is S<int>.
20785 Then, we should unify `int' and `U'. */
20787 else
20788 /* There's no chance of unification succeeding. */
20793 }
20800 {
20803 tree a;
20809 /* CV qualifications for methods can never be deduced, they must
20810 match exactly. We need to check them explicitly here,
20811 because type_unification_real treats them as any other
20812 cv-qualified parameter. */
20814 && (!check_cv_quals_for_unify
20842 {
20854 }
20857 }
20860 /* Unify a pointer to member with a pointer to member function, which
20861 deduces the type of the member as a function type. */
20863 {
20864 /* Check top-level cv qualifiers */
20872 /* Determine the type of the function we are unifying against. */
20876 }
20895 /* Matched cases are handled by the ARG == PARM test above. */
20899 /* We might get a variable as a non-type template argument in parm if the
20900 corresponding parameter is type-dependent. Make any necessary
20901 adjustments based on whether arg is a reference. */
20905 {
20910 }
20911 /* Now use the normal expression code to check whether they match. */
20922 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
20923 or UNDERLYING_TYPE nodes. */
20927 /* Unification fails if we hit an error node. */
20932 {
20942 }
20943 /* FALLTHRU */
20946 /* An unresolved overload is a nondeduced context. */
20950 expr:
20951 /* We must be looking at an expression. This can happen with
20952 something like:
20954 template <int I>
20955 void foo(S<I>, S<I + 2>);
20957 This is a "nondeduced context":
20959 [deduct.type]
20961 The nondeduced contexts are:
20963 --A type that is a template-id in which one or more of
20964 the template-arguments is an expression that references
20965 a template-parameter.
20967 In these cases, we assume deduction succeeded, but don't
20968 actually infer any unifications. */
20973 else
20975 }
20976 }
20977 #undef RECUR_AND_CHECK_FAILURE
20978 \f
20979 /* Note that DECL can be defined in this translation unit, if
20980 required. */
20982 static void
20984 {
20985 tree clone;
20989 }
20991 /* Called if RESULT is explicitly instantiated, or is a member of an
20992 explicitly instantiated class. */
20994 void
20996 {
20999 /* If this entity has already been written out, it's too late to
21000 make any modifications. */
21004 /* For anonymous namespace we don't need to do anything. */
21006 {
21009 }
21012 /* The TREE_PUBLIC flag for function declarations will have been
21013 set correctly by tsubst. */
21016 /* This might have been set by an earlier implicit instantiation. */
21021 else
21022 {
21025 /* Always make artificials weak. */
21028 /* For WIN32 we also want to put explicit instantiations in
21029 linkonce sections. */
21032 }
21034 /* If EXTERN_P, then this function will not be emitted -- unless
21035 followed by an explicit instantiation, at which point its linkage
21036 will be adjusted. If !EXTERN_P, then this function will be
21037 emitted here. In neither circumstance do we want
21038 import_export_decl to adjust the linkage. */
21040 }
21042 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
21043 important template arguments. If any are missing, we check whether
21044 they're important by using error_mark_node for substituting into any
21045 args that were used for partial ordering (the ones between ARGS and END)
21046 and seeing if it bubbles up. */
21048 static bool
21050 {
21055 {
21058 }
21060 {
21064 }
21066 }
21068 /* Given two function templates PAT1 and PAT2, return:
21070 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
21071 -1 if PAT2 is more specialized than PAT1.
21072 0 if neither is more specialized.
21074 LEN indicates the number of parameters we should consider
21075 (defaulted parameters should not be considered).
21077 The 1998 std underspecified function template partial ordering, and
21078 DR214 addresses the issue. We take pairs of arguments, one from
21079 each of the templates, and deduce them against each other. One of
21080 the templates will be more specialized if all the *other*
21081 template's arguments deduce against its arguments and at least one
21082 of its arguments *does* *not* deduce against the other template's
21083 corresponding argument. Deduction is done as for class templates.
21084 The arguments used in deduction have reference and top level cv
21085 qualifiers removed. Iff both arguments were originally reference
21086 types *and* deduction succeeds in both directions, an lvalue reference
21087 wins against an rvalue reference and otherwise the template
21088 with the more cv-qualified argument wins for that pairing (if
21089 neither is more cv-qualified, they both are equal). Unlike regular
21090 deduction, after all the arguments have been deduced in this way,
21091 we do *not* verify the deduced template argument values can be
21092 substituted into non-deduced contexts.
21094 The logic can be a bit confusing here, because we look at deduce1 and
21095 targs1 to see if pat2 is at least as specialized, and vice versa; if we
21096 can find template arguments for pat1 to make arg1 look like arg2, that
21097 means that arg2 is at least as specialized as arg1. */
21099 int
21101 {
21114 /* Remove the this parameter from non-static member functions. If
21115 one is a non-static member function and the other is not a static
21116 member function, remove the first parameter from that function
21117 also. This situation occurs for operator functions where we
21118 locate both a member function (with this pointer) and non-member
21119 operator (with explicit first operand). */
21121 {
21126 }
21128 {
21131 {
21132 len--;
21134 }
21135 }
21137 /* If only one is a conversion operator, they are unordered. */
21141 /* Consider the return type for a conversion function */
21143 {
21146 len++;
21147 }
21149 processing_template_decl++;
21155 /* Stop when an ellipsis is seen. */
21157 {
21168 {
21169 /* When both arguments are pack expansions, we need only
21170 unify the patterns themselves. */
21174 /* This is the last comparison we need to do. */
21176 }
21179 {
21183 }
21186 {
21190 }
21196 {
21202 /* Setup the parameter vector, which contains only ARG1. */
21205 /* Setup the argument vector, which contains the remaining
21206 arguments. */
21215 /* We cannot deduce in the other direction, because ARG1 is
21216 a pack expansion but ARG2 is not. */
21218 }
21220 {
21226 /* Setup the parameter vector, which contains only ARG1. */
21229 /* Setup the argument vector, which contains the remaining
21230 arguments. */
21239 /* We cannot deduce in the other direction, because ARG2 is
21240 a pack expansion but ARG1 is not.*/
21242 }
21244 else
21245 {
21246 /* The normal case, where neither argument is a pack
21247 expansion. */
21254 }
21256 /* If we couldn't deduce arguments for tparms1 to make arg1 match
21257 arg2, then arg2 is not as specialized as arg1. */
21263 /* "If, for a given type, deduction succeeds in both directions
21264 (i.e., the types are identical after the transformations above)
21265 and both P and A were reference types (before being replaced with
21266 the type referred to above):
21267 - if the type from the argument template was an lvalue reference and
21268 the type from the parameter template was not, the argument type is
21269 considered to be more specialized than the other; otherwise,
21270 - if the type from the argument template is more cv-qualified
21271 than the type from the parameter template (as described above),
21272 the argument type is considered to be more specialized than the other;
21273 otherwise,
21274 - neither type is more specialized than the other." */
21277 {
21279 {
21282 else
21284 }
21286 {
21291 }
21292 }
21295 /* We've failed to deduce something in either direction.
21296 These must be unordered. */
21301 /* We have already processed all of the arguments in our
21302 handing of the pack expansion type. */
21307 }
21309 /* "In most cases, all template parameters must have values in order for
21310 deduction to succeed, but for partial ordering purposes a template
21311 parameter may remain without a value provided it is not used in the
21312 types being used for partial ordering."
21314 Thus, if we are missing any of the targs1 we need to substitute into
21315 origs1, then pat2 is not as specialized as pat1. This can happen when
21316 there is a nondeduced context. */
21322 processing_template_decl--;
21324 /* If both deductions succeed, the partial ordering selects the more
21325 constrained template. */
21327 {
21332 }
21334 /* All things being equal, if the next argument is a pack expansion
21335 for one function but not for the other, prefer the
21336 non-variadic function. FIXME this is bogus; see c++/41958. */
21340 {
21343 }
21349 else
21351 }
21353 /* Determine which of two partial specializations of TMPL is more
21354 specialized.
21356 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
21357 to the first partial specialization. The TREE_PURPOSE is the
21358 innermost set of template parameters for the partial
21359 specialization. PAT2 is similar, but for the second template.
21361 Return 1 if the first partial specialization is more specialized;
21362 -1 if the second is more specialized; 0 if neither is more
21363 specialized.
21365 See [temp.class.order] for information about determining which of
21366 two templates is more specialized. */
21368 static int
21370 {
21371 tree targs;
21380 /* Just like what happens for functions, if we are ordering between
21381 different template specializations, we may encounter dependent
21382 types in the arguments, and we need our dependency check functions
21383 to behave correctly. */
21387 {
21390 }
21394 {
21397 }
21400 /* If both deductions succeed, the partial ordering selects the more
21401 constrained template. */
21405 /* In the case of a tie where at least one of the templates
21406 has a parameter pack at the end, the template with the most
21407 non-packed parameters wins. */
21409 && any_deductions
21412 {
21418 /* We don't count the pack expansion at the end. */
21428 }
21431 }
21433 /* Return the template arguments that will produce the function signature
21434 DECL from the function template FN, with the explicit template
21435 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
21436 also match. Return NULL_TREE if no satisfactory arguments could be
21437 found. */
21439 static tree
21441 {
21445 tree decl_arg_types;
21448 tree arg;
21452 /* Never do unification on the 'this' parameter. */
21473 }
21475 /* Return the innermost template arguments that, when applied to a partial
21476 specialization SPEC_TMPL of TMPL, yield the ARGS.
21478 For example, suppose we have:
21480 template <class T, class U> struct S {};
21481 template <class T> struct S<T*, int> {};
21483 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
21484 partial specialization and the ARGS will be {double*, int}. The resulting
21485 vector will be {double}, indicating that `T' is bound to `double'. */
21487 static tree
21489 {
21491 tree spec_args
21494 tree deduced_args;
21495 tree innermost_deduced_args;
21499 {
21503 innermost_deduced_args);
21504 }
21505 else
21509 again:
21518 {
21520 {
21526 }
21528 }
21532 {
21535 }
21537 /* Verify that nondeduced template arguments agree with the type
21538 obtained from argument deduction.
21540 For example:
21542 struct A { typedef int X; };
21543 template <class T, class U> struct C {};
21544 template <class T> struct C<T, typename T::X> {};
21546 Then with the instantiation `C<A, int>', we can deduce that
21547 `T' is `A' but unify () does not check whether `typename T::X'
21548 is `int'. */
21557 /* We only need to check the innermost arguments; the other
21558 arguments will always agree. */
21563 /* Now that we have bindings for all of the template arguments,
21564 ensure that the arguments deduced for the template template
21565 parameters have compatible template parameter lists. See the use
21566 of template_template_parm_bindings_ok_p in fn_type_unification
21567 for more information. */
21572 }
21574 // Compare two function templates T1 and T2 by deducing bindings
21575 // from one against the other. If both deductions succeed, compare
21576 // constraints to see which is more constrained.
21577 static int
21579 {
21584 {
21587 }
21590 {
21593 }
21595 // If both deductions succeed, then one may be more constrained.
21600 }
21602 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
21603 Return the TREE_LIST node with the most specialized template, if
21604 any. If there is no most specialized template, the error_mark_node
21605 is returned.
21607 Note that this function does not look at, or modify, the
21608 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
21609 returned is one of the elements of INSTANTIATIONS, callers may
21610 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
21611 and retrieve it from the value returned. */
21613 tree
21615 {
21622 {
21627 {
21628 /* Equally specialized, move to next function. If there
21629 is no next function, nothing's most specialized. */
21634 }
21635 }
21638 /* Now verify that champ is better than everything earlier in the
21639 instantiation list. */
21642 {
21645 }
21646 }
21648 processing_template_decl--;
21654 }
21656 /* If DECL is a specialization of some template, return the most
21657 general such template. Otherwise, returns NULL_TREE.
21659 For example, given:
21661 template <class T> struct S { template <class U> void f(U); };
21663 if TMPL is `template <class U> void S<int>::f(U)' this will return
21664 the full template. This function will not trace past partial
21665 specializations, however. For example, given in addition:
21667 template <class T> struct S<T*> { template <class U> void f(U); };
21669 if TMPL is `template <class U> void S<int*>::f(U)' this will return
21670 `template <class T> template <class U> S<T*>::f(U)'. */
21672 tree
21674 {
21676 {
21679 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
21680 template friend, or a FIELD_DECL for a capture pack. */
21683 }
21685 /* Look for more and more general templates. */
21687 {
21688 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
21689 (See cp-tree.h for details.) */
21698 /* Stop if we run into an explicitly specialized class template. */
21705 }
21708 }
21710 /* Return the most specialized of the template partial specializations
21711 which can produce TARGET, a specialization of some class or variable
21712 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
21713 a TEMPLATE_DECL node corresponding to the partial specialization, while
21714 the TREE_PURPOSE is the set of template arguments that must be
21715 substituted into the template pattern in order to generate TARGET.
21717 If the choice of partial specialization is ambiguous, a diagnostic
21718 is issued, and the error_mark_node is returned. If there are no
21719 partial specializations matching TARGET, then NULL_TREE is
21720 returned, indicating that the primary template should be used. */
21722 static tree
21724 {
21726 tree t;
21727 tree champ;
21734 {
21738 }
21740 {
21743 }
21745 {
21749 }
21750 else
21755 /* For determining which partial specialization to use, only the
21756 innermost args are interesting. */
21758 {
21761 }
21764 {
21765 tree spec_args;
21769 {
21770 /* Substitute in the template args from the enclosing class. */
21774 }
21781 {
21785 /* Keep the candidate only if the constraints are satisfied,
21786 or if we're not compiling with concepts. */
21789 {
21792 }
21793 }
21794 }
21804 {
21807 ;
21808 else
21809 {
21811 {
21814 {
21817 }
21818 }
21820 }
21821 }
21825 {
21828 {
21831 }
21832 }
21835 {
21842 else
21846 {
21851 }
21854 }
21857 }
21859 /* Explicitly instantiate DECL. */
21861 void
21863 {
21868 /* An error occurred, for which grokdeclarator has already issued
21869 an appropriate message. */
21872 {
21875 }
21881 {
21882 /* There is an asymmetry here in the way VAR_DECLs and
21883 FUNCTION_DECLs are handled by grokdeclarator. In the case of
21884 the latter, the DECL we get back will be marked as a
21885 template instantiation, and the appropriate
21886 DECL_TEMPLATE_INFO will be set up. This does not happen for
21887 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
21888 should handle VAR_DECLs as it currently handles
21889 FUNCTION_DECLs. */
21891 {
21894 }
21897 {
21900 }
21902 {
21907 }
21908 }
21910 {
21913 }
21914 else
21917 /* Check for various error cases. Note that if the explicit
21918 instantiation is valid the RESULT will currently be marked as an
21919 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
21920 until we get here. */
21923 {
21924 /* DR 259 [temp.spec].
21926 Both an explicit instantiation and a declaration of an explicit
21927 specialization shall not appear in a program unless the explicit
21928 instantiation follows a declaration of the explicit specialization.
21930 For a given set of template parameters, if an explicit
21931 instantiation of a template appears after a declaration of an
21932 explicit specialization for that template, the explicit
21933 instantiation has no effect. */
21935 }
21937 {
21938 /* [temp.spec]
21940 No program shall explicitly instantiate any template more
21941 than once.
21943 We check DECL_NOT_REALLY_EXTERN so as not to complain when
21944 the first instantiation was `extern' and the second is not,
21945 and EXTERN_P for the opposite case. */
21948 /* If an "extern" explicit instantiation follows an ordinary
21949 explicit instantiation, the template is instantiated. */
21952 }
21954 {
21957 }
21959 {
21962 }
21965 ;
21967 {
21970 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
21973 }
21974 else
21982 }
21984 static void
21986 {
21992 {
21995 }
21996 }
21998 /* Called from do_type_instantiation through binding_table_foreach to
21999 do recursive instantiation for the type bound in ENTRY. */
22000 static void
22002 {
22008 }
22010 /* Called from do_type_instantiation to instantiate a member
22011 (a member function or a static member variable) of an
22012 explicitly instantiated class template. */
22013 static void
22015 {
22020 }
22022 /* Perform an explicit instantiation of template class T. STORAGE, if
22023 non-null, is the RID for extern, inline or static. COMPLAIN is
22024 nonzero if this is called from the parser, zero if called recursively,
22025 since the standard is unclear (as detailed below). */
22027 void
22029 {
22039 {
22040 tree tmpl =
22044 else
22047 }
22052 {
22055 t);
22057 }
22060 {
22062 {
22064 {
22067 "ISO C++ 1998 forbids the use of %<extern%> on "
22069 }
22070 else
22072 "ISO C++ forbids the use of %qE"
22074 }
22082 else
22083 {
22085 storage);
22087 }
22088 }
22091 {
22092 /* DR 259 [temp.spec].
22094 Both an explicit instantiation and a declaration of an explicit
22095 specialization shall not appear in a program unless the explicit
22096 instantiation follows a declaration of the explicit specialization.
22098 For a given set of template parameters, if an explicit
22099 instantiation of a template appears after a declaration of an
22100 explicit specialization for that template, the explicit
22101 instantiation has no effect. */
22103 }
22105 {
22106 /* [temp.spec]
22108 No program shall explicitly instantiate any template more
22109 than once.
22111 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
22112 instantiation was `extern'. If EXTERN_P then the second is.
22113 These cases are OK. */
22120 /* If we've already instantiated the template, just return now. */
22123 }
22131 {
22132 tree tmp;
22134 /* In contrast to implicit instantiation, where only the
22135 declarations, and not the definitions, of members are
22136 instantiated, we have here:
22138 [temp.explicit]
22140 The explicit instantiation of a class template specialization
22141 implies the instantiation of all of its members not
22142 previously explicitly specialized in the translation unit
22143 containing the explicit instantiation.
22145 Of course, we can't instantiate member template classes, since
22146 we don't have any arguments for them. Note that the standard
22147 is unclear on whether the instantiation of the members are
22148 *explicit* instantiations or not. However, the most natural
22149 interpretation is that it should be an explicit instantiation. */
22165 }
22166 }
22168 /* Given a function DECL, which is a specialization of TMPL, modify
22169 DECL to be a re-instantiation of TMPL with the same template
22170 arguments. TMPL should be the template into which tsubst'ing
22171 should occur for DECL, not the most general template.
22173 One reason for doing this is a scenario like this:
22175 template <class T>
22176 void f(const T&, int i);
22178 void g() { f(3, 7); }
22180 template <class T>
22181 void f(const T& t, const int i) { }
22183 Note that when the template is first instantiated, with
22184 instantiate_template, the resulting DECL will have no name for the
22185 first parameter, and the wrong type for the second. So, when we go
22186 to instantiate the DECL, we regenerate it. */
22188 static void
22190 {
22191 /* The arguments used to instantiate DECL, from the most general
22192 template. */
22193 tree code_pattern;
22197 /* Make sure that we can see identifiers, and compute access
22198 correctly. */
22202 {
22203 tree decl_parm;
22204 tree pattern_parm;
22205 tree specs;
22219 specs);
22221 /* Merge parameter declarations. */
22224 pattern_parm
22228 {
22229 tree parm_type;
22230 tree attributes;
22235 NULL_TREE);
22241 {
22244 }
22247 }
22248 /* Merge any parameters that match with the function parameter
22249 pack. */
22251 {
22253 tree expanded_types;
22254 /* Expand the TYPE_PACK_EXPANSION that provides the types for
22255 the parameters in this function parameter pack. */
22260 {
22261 tree parm_type;
22262 tree attributes;
22265 /* Rename the parameter to include the index. */
22274 {
22277 }
22279 }
22280 }
22281 /* Merge additional specifiers from the CODE_PATTERN. */
22285 }
22287 {
22295 }
22296 else
22300 }
22302 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
22303 substituted to get DECL. */
22305 tree
22307 {
22310 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
22311 for the instantiation. This is not always the most general
22312 template. Consider, for example:
22314 template <class T>
22315 struct S { template <class U> void f();
22316 template <> void f<int>(); };
22318 and an instantiation of S<double>::f<int>. We want TD to be the
22319 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
22321 more general template. */
22323 /* We must also deal with friend templates. Given:
22325 template <class T> struct S {
22326 template <class U> friend void f() {};
22327 };
22329 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
22330 so far as the language is concerned, but that's still
22331 where we get the pattern for the instantiation from. On
22332 other hand, if the definition comes outside the class, say:
22334 template <class T> struct S {
22335 template <class U> friend void f();
22336 };
22337 template <class U> friend void f() {}
22339 we don't need to look any further. That's what the check for
22340 DECL_INITIAL is for. */
22344 {
22345 /* The present template, TD, should not be a definition. If it
22346 were a definition, we should be using it! Note that we
22347 cannot restructure the loop to just keep going until we find
22348 a template with a definition, since that might go too far if
22349 a specialization was declared, but not defined. */
22351 /* Fetch the more general template. */
22353 }
22356 }
22358 /* Returns true if we need to instantiate this template instance even if we
22359 know we aren't going to emit it. */
22361 bool
22363 {
22364 /* We always instantiate inline functions so that we can inline them. An
22365 explicit instantiation declaration prohibits implicit instantiation of
22366 non-inline functions. With high levels of optimization, we would
22367 normally inline non-inline functions -- but we're not allowed to do
22368 that for "extern template" functions. Therefore, we check
22369 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
22373 /* And we need to instantiate static data members so that
22374 their initializers are available in integral constant
22375 expressions. */
22378 }
22380 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
22381 instantiate it now, modifying TREE_TYPE (fn). */
22383 void
22385 {
22388 /* Don't instantiate a noexcept-specification from template context. */
22403 {
22407 {
22422 }
22423 else
22427 }
22430 {
22433 else
22435 }
22436 }
22438 /* Produce the definition of D, a _DECL generated from a template. If
22439 DEFER_OK is true, then we don't have to actually do the
22440 instantiation now; we just have to do it sometime. Normally it is
22441 an error if this is an explicit instantiation but D is undefined.
22442 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
22443 instantiated class template. */
22445 tree
22447 {
22449 tree gen_args;
22450 tree args;
22451 tree td;
22452 tree code_pattern;
22453 tree spec;
22454 tree gen_tmpl;
22462 /* This function should only be used to instantiate templates for
22463 functions and static member variables. */
22466 /* A concept is never instantiated. */
22469 /* Variables are never deferred; if instantiation is required, they
22470 are instantiated right away. That allows for better code in the
22471 case that an expression refers to the value of the variable --
22472 if the variable has a constant value the referring expression can
22473 take advantage of that fact. */
22477 /* Don't instantiate cloned functions. Instead, instantiate the
22478 functions they cloned. */
22486 /* D has already been instantiated or explicitly specialized, so
22487 there's nothing for us to do here.
22489 It might seem reasonable to check whether or not D is an explicit
22490 instantiation, and, if so, stop here. But when an explicit
22491 instantiation is deferred until the end of the compilation,
22492 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
22493 the instantiation. */
22496 /* Check to see whether we know that this template will be
22497 instantiated in some other file, as with "extern template"
22498 extension. */
22501 /* In general, we do not instantiate such templates. */
22509 /* We should already have the extra args. */
22512 /* And what's in the hash table should match D. */
22516 /* This needs to happen before any tsubsting. */
22522 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
22523 for the instantiation. */
22528 {
22529 /* Look up an explicit specialization, if any. */
22533 {
22536 }
22537 }
22541 /* We should never be trying to instantiate a member of a class
22542 template or partial specialization. */
22547 /* In the case of a friend template whose definition is provided
22548 outside the class, we may have too many arguments. Drop the
22549 ones we don't need. The same is true for specializations. */
22550 args = get_innermost_template_args
22554 {
22560 }
22561 else
22562 {
22567 else
22569 }
22571 /* We may be in the middle of deferred access check. Disable it now. */
22574 /* Unless an explicit instantiation directive has already determined
22575 the linkage of D, remember that a definition is available for
22576 this entity. */
22586 /* If D is a member of an explicitly instantiated class template,
22587 and no definition is available, treat it like an implicit
22588 instantiation. */
22591 {
22592 /* Leave linkage flags alone on instantiations with anonymous
22593 visibility. */
22595 {
22598 }
22600 }
22602 /* Defer all other templates, unless we have been explicitly
22603 forbidden from doing so. */
22605 template. */
22606 ! pattern_defined
22607 /* If it's OK to postpone instantiation, do so. */
22608 || defer_ok
22609 /* If this is a static data member that will be defined
22610 elsewhere, we don't want to instantiate the entire data
22611 member, but we do want to instantiate the initializer so that
22612 we can substitute that elsewhere. */
22614 /* Handle here a deleted function too, avoid generating
22615 its body (c++/61080). */
22617 {
22618 /* The definition of the static data member is now required so
22619 we must substitute the initializer. */
22623 {
22624 tree ns;
22625 tree init;
22634 args,
22637 /* If instantiating the initializer involved instantiating this
22638 again, don't call cp_finish_decl twice. */
22640 {
22641 /* Make sure the initializer is still constant, in case of
22642 circular dependency (template/instantiate6.C). */
22643 const_init
22647 LOOKUP_ONLYCONVERTING);
22648 }
22652 }
22654 /* We restore the source position here because it's used by
22655 add_pending_template. */
22661 /* [temp.explicit]
22663 The definition of a non-exported function template, a
22664 non-exported member function template, or a non-exported
22665 member function or static data member of a class template
22666 shall be present in every translation unit in which it is
22667 explicitly instantiated. */
22671 /* If we're in unevaluated context, we just wanted to get the
22672 constant value; this isn't an odr use, so don't queue
22673 a full instantiation. */
22676 /* ??? Historically, we have instantiated inline functions, even
22677 when marked as "extern template". */
22681 }
22682 /* Tell the repository that D is available in this translation unit
22683 -- and see if it is supposed to be instantiated here. */
22685 {
22686 /* In a PCH file, despite the fact that the repository hasn't
22687 requested instantiation in the PCH it is still possible that
22688 an instantiation will be required in a file that includes the
22689 PCH. */
22692 /* Instantiate inline functions so that the inliner can do its
22693 job, even though we'll not be emitting a copy of this
22694 function. */
22697 }
22700 tree fn_context;
22711 else
22712 {
22716 }
22718 /* Mark D as instantiated so that recursive calls to
22719 instantiate_decl do not try to instantiate it again. */
22722 /* Regenerate the declaration in case the template has been modified
22723 by a subsequent redeclaration. */
22726 /* We already set the file and line above. Reset them now in case
22727 they changed as a result of calling regenerate_decl_from_template. */
22731 {
22732 tree init;
22735 /* Clear out DECL_RTL; whatever was there before may not be right
22736 since we've reset the type of the declaration. */
22740 /* The initializer is placed in DECL_INITIAL by
22741 regenerate_decl_from_template so we don't need to
22742 push/pop_access_scope again here. Pull it out so that
22743 cp_finish_decl can process it. */
22748 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
22749 initializer. That function will defer actual emission until
22750 we have a chance to determine linkage. */
22753 /* Enter the scope of D so that access-checking works correctly. */
22766 }
22770 {
22772 tree tmpl_parm;
22773 tree spec_parm;
22777 /* Save away the current list, in case we are instantiating one
22778 template from within the body of another. */
22781 /* Set up the list of local specializations. */
22784 /* Set up context. */
22788 else
22789 {
22791 {
22792 /* When instantiating a lambda's templated function
22793 operator, we need to push the non-lambda class scope
22794 of the lambda itself so that the nested function
22795 stack is sufficiently correct to deal with this
22796 capture. */
22798 do
22803 }
22805 }
22807 /* Some typedefs referenced from within the template code need to be
22808 access checked at template instantiation time, i.e now. These
22809 types were added to the template at parsing time. Let's get those
22810 and perform the access checks then. */
22812 args);
22814 /* Create substitution entries for the parameters. */
22818 {
22822 }
22824 {
22826 {
22829 }
22830 else
22831 {
22832 /* Register the (value) argument pack as a specialization of
22833 TMPL_PARM, then move on. */
22836 }
22837 }
22840 /* Substitute into the body of the function. */
22844 else
22845 {
22850 /* Set the current input_location to the end of the function
22851 so that finish_function knows where we are. */
22852 input_location
22855 /* Remember if we saw an infinite loop in the template. */
22856 current_function_infinite_loop
22858 }
22860 /* We don't need the local specializations any more. */
22864 /* Finish the function. */
22868 else
22869 {
22872 }
22878 }
22880 /* We're not deferring instantiation any more. */
22885 else
22891 out:
22900 }
22902 /* Run through the list of templates that we wish we could
22903 instantiate, and instantiate any we can. RETRIES is the
22904 number of times we retry pending template instantiation. */
22906 void
22908 {
22912 /* Instantiating templates may trigger vtable generation. This in turn
22913 may require further template instantiations. We place a limit here
22914 to avoid infinite loop. */
22916 {
22920 "template instantiation depth exceeds maximum of %d"
22921 " instantiating %q+D, possibly from virtual table generation"
22925 /* Pretend that we defined it. */
22928 }
22930 do
22931 {
22936 {
22941 {
22942 tree fn;
22945 {
22949 fn;
22957 }
22960 }
22961 else
22962 {
22965 {
22966 instantiation
22972 }
22976 }
22979 /* If INSTANTIATION has been instantiated, then we don't
22980 need to consider it again in the future. */
22982 else
22983 {
22986 }
22989 }
22991 }
22995 }
22997 /* Substitute ARGVEC into T, which is a list of initializers for
22998 either base class or a non-static data member. The TREE_PURPOSEs
22999 are DECLs, and the TREE_VALUEs are the initializer values. Used by
23000 instantiate_decl. */
23002 static tree
23004 {
23008 {
23009 tree decl;
23010 tree init;
23016 {
23017 tree expr;
23018 tree arg;
23020 /* Expand the base class expansion type into separate base
23021 classes. */
23023 tf_warning_or_error,
23024 NULL_TREE);
23028 /* We'll be building separate TREE_LISTs of arguments for
23029 each base. */
23035 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
23036 expand each argument in the TREE_VALUE of t. */
23043 /* VOID_TYPE_NODE is used to indicate
23044 value-initialization. */
23045 {
23048 }
23049 else
23050 {
23051 /* Substitute parameter packs into each argument in the
23052 TREE_LIST. */
23055 {
23056 tree expanded_exprs;
23058 /* Expand the argument. */
23060 expanded_exprs
23062 tf_warning_or_error,
23063 NULL_TREE);
23067 /* Prepend each of the expanded expressions to the
23068 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
23070 {
23075 }
23076 }
23079 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
23080 since we built them backwards. */
23082 {
23085 }
23086 }
23087 }
23090 {
23092 {
23096 }
23097 else
23098 {
23099 tree tmp;
23114 /* If we had an initializer but it instantiated to nothing,
23115 value-initialize the object. This will only occur when
23116 the initializer was a pack expansion where the parameter
23117 packs used in that expansion were of length zero. */
23120 }
23123 {
23127 }
23128 }
23129 }
23131 }
23133 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
23135 static void
23137 {
23142 else
23144 }
23146 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
23147 is the instantiation (which should have been created with
23148 start_enum) and ARGS are the template arguments to use. */
23150 static void
23152 {
23153 tree e;
23159 {
23160 tree value;
23161 tree decl;
23164 /* Note that in a template enum, the TREE_VALUE is the
23165 CONST_DECL, not the corresponding INTEGER_CST. */
23170 /* Give this enumeration constant the correct access. */
23173 /* Actually build the enumerator itself. Here we're assuming that
23174 enumerators can't have dependent attributes. */
23177 }
23187 }
23189 /* DECL is a FUNCTION_DECL that is a template specialization. Return
23190 its type -- but without substituting the innermost set of template
23191 arguments. So, innermost set of template parameters will appear in
23192 the type. */
23194 tree
23196 {
23197 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
23199 }
23201 /* Return truthvalue if we're processing a template different from
23202 the last one involved in diagnostics. */
23203 bool
23205 {
23207 }
23209 /* Remember current template involved in diagnostics. */
23210 void
23212 {
23214 }
23218 {
23220 }
23222 /* Return TRUE if current_function_decl is being instantiated, false
23223 otherwise. */
23225 bool
23227 {
23230 }
23232 /* [temp.param] Check that template non-type parm TYPE is of an allowable
23233 type. Return zero for ok, nonzero for disallowed. Issue error and
23234 warning messages under control of COMPLAIN. */
23236 static int
23238 {
23253 /* A bound template template parm could later be instantiated to have a valid
23254 nontype parm type via an alias template. */
23260 {
23263 else
23265 type);
23266 }
23268 }
23270 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
23271 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
23273 static bool
23275 {
23276 tree scope;
23278 /* [temp.dep.type]
23280 A type is dependent if it is:
23282 -- a template parameter. Template template parameters are types
23283 for us (since TYPE_P holds true for them) so we handle
23284 them here. */
23288 /* -- a qualified-id with a nested-name-specifier which contains a
23289 class-name that names a dependent type or whose unqualified-id
23290 names a dependent type. */
23294 /* An alias template specialization can be dependent even if the
23295 resulting type is not. */
23299 /* -- a cv-qualified type where the cv-unqualified type is
23300 dependent.
23301 No code is necessary for this bullet; the code below handles
23302 cv-qualified types, and we don't want to strip aliases with
23303 TYPE_MAIN_VARIANT because of DR 1558. */
23304 /* -- a compound type constructed from any dependent type. */
23314 {
23315 tree arg_type;
23320 arg_type;
23325 }
23326 /* -- an array type constructed from any dependent type or whose
23327 size is specified by a constant expression that is
23328 value-dependent.
23330 We checked for type- and value-dependence of the bounds in
23331 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
23333 {
23338 }
23340 /* -- a template-id in which either the template name is a template
23341 parameter ... */
23344 /* ... or any of the template arguments is a dependent type or
23345 an expression that is type-dependent or value-dependent. */
23347 && (any_dependent_template_arguments_p
23351 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
23352 dependent; if the argument of the `typeof' expression is not
23353 type-dependent, then it should already been have resolved. */
23359 /* A template argument pack is dependent if any of its packed
23360 arguments are. */
23362 {
23368 }
23370 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
23371 be template parameters. */
23378 /* The standard does not specifically mention types that are local
23379 to template functions or local classes, but they should be
23380 considered dependent too. For example:
23382 template <int I> void f() {
23383 enum E { a = I };
23384 S<sizeof (E)> s;
23385 }
23387 The size of `E' cannot be known until the value of `I' has been
23388 determined. Therefore, `E' must be considered dependent. */
23392 /* Don't use type_dependent_expression_p here, as it can lead
23393 to infinite recursion trying to determine whether a lambda
23394 nested in a lambda is dependent (c++/47687). */
23398 && (any_dependent_template_arguments_p
23402 /* Other types are non-dependent. */
23404 }
23406 /* Returns TRUE if TYPE is dependent, in the sense of
23407 [temp.dep.type]. Note that a NULL type is considered dependent. */
23409 bool
23411 {
23412 /* If there are no template parameters in scope, then there can't be
23413 any dependent types. */
23415 {
23416 /* If we are not processing a template, then nobody should be
23417 providing us with a dependent type. */
23421 }
23423 /* If the type is NULL, we have not computed a type for the entity
23424 in question; in that case, the type is dependent. */
23428 /* Erroneous types can be considered non-dependent. */
23432 /* If we have not already computed the appropriate value for TYPE,
23433 do so now. */
23435 {
23438 }
23441 }
23443 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
23444 lookup. In other words, a dependent type that is not the current
23445 instantiation. */
23447 bool
23449 {
23452 }
23454 /* T is a SCOPE_REF; return whether we need to consider it
23455 instantiation-dependent so that we can check access at instantiation
23456 time even though we know which member it resolves to. */
23458 static bool
23460 {
23466 else
23468 }
23470 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
23471 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
23472 expression. */
23474 /* Note that this predicate is not appropriate for general expressions;
23475 only constant expressions (that satisfy potential_constant_expression)
23476 can be tested for value dependence. */
23478 bool
23480 {
23484 /* A name declared with a dependent type. */
23489 {
23491 /* A dependent member function of the current instantiation. */
23495 /* A dependent member function of the current instantiation. */
23502 /* A name that has not been looked up -- must be dependent. */
23506 /* A non-type template parm. */
23510 /* A non-type template parm. */
23516 /* A constant with literal type and is initialized
23517 with an expression that is value-dependent.
23519 Note that a non-dependent parenthesized initializer will have
23520 already been replaced with its constant value, so if we see
23521 a TREE_LIST it must be dependent. */
23525 /* cp_finish_decl doesn't fold reference initializers. */
23537 /* These expressions are value-dependent if the type to which
23538 the cast occurs is dependent or the expression being casted
23539 is value-dependent. */
23540 {
23546 /* A functional cast has a list of operands. */
23549 {
23550 /* If there are no operands, it must be an expression such
23551 as "int()". This should not happen for aggregate types
23552 because it would form non-constant expressions. */
23557 }
23563 }
23568 /* FALLTHRU */
23571 /* A `sizeof' expression is value-dependent if the operand is
23572 type-dependent or is a pack expansion. */
23581 /* An 'encode' expression is value-dependent if the operand is
23582 type-dependent. */
23591 /* All instantiation-dependent expressions should also be considered
23592 value-dependent. */
23600 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
23601 is value-dependent. */
23602 {
23611 }
23614 {
23618 }
23629 {
23633 }
23636 /* Treat all requires-expressions as value-dependent so
23637 we don't try to fold them. */
23644 {
23651 {
23653 /* In a call to a constexpr member function, look through the
23654 implicit ADDR_EXPR on the object argument so that it doesn't
23655 cause the call to be considered value-dependent. We also
23656 look through it in potential_constant_expression. */
23663 }
23665 }
23668 /* If a TEMPLATE_ID_EXPR involves a dependent name, it will be
23669 type-dependent. */
23674 {
23676 tree val;
23683 }
23686 /* Treat a GNU statement expression as dependent to avoid crashing
23687 under instantiate_non_dependent_expr; it can't be constant. */
23691 /* A constant expression is value-dependent if any subexpression is
23692 value-dependent. */
23694 {
23701 {
23705 {
23708 /* In some cases, some of the operands may be missing.l
23709 (For example, in the case of PREDECREMENT_EXPR, the
23710 amount to increment by may be missing.) That doesn't
23711 make the expression dependent. */
23714 }
23715 }
23719 }
23721 }
23723 /* The expression is not value-dependent. */
23725 }
23727 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
23728 [temp.dep.expr]. Note that an expression with no type is
23729 considered dependent. Other parts of the compiler arrange for an
23730 expression with type-dependent subexpressions to have no type, so
23731 this function doesn't have to be fully recursive. */
23733 bool
23735 {
23742 /* An unresolved name is always dependent. */
23748 /* A fold expression is type-dependent. */
23755 /* Some expression forms are never type-dependent. */
23769 /* The types of these expressions depends only on the type to which
23770 the cast occurs. */
23779 /* The types of these expressions depends only on the type created
23780 by the expression. */
23783 {
23784 /* For NEW_EXPR tree nodes created inside a template, either
23785 the object type itself or a TREE_LIST may appear as the
23786 operand 1. */
23789 /* This is an array type. We need to check array dimensions
23790 as well. */
23792 || value_dependent_expression_p
23794 else
23796 }
23799 {
23803 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
23804 contains an identifier associated by name lookup with one or more
23805 declarations declared with a dependent type, or...a
23806 nested-name-specifier or qualified-id that names a member of an
23807 unknown specialization. */
23810 }
23820 {
23821 tree elt;
23825 {
23828 }
23830 }
23832 /* A static data member of the current instantiation with incomplete
23833 array type is type-dependent, as the definition and specializations
23834 can have different bounds. */
23841 /* An array of unknown bound depending on a variadic parameter, eg:
23843 template<typename... Args>
23844 void foo (Args... args)
23845 {
23846 int arr[] = { args... };
23847 }
23849 template<int... vals>
23850 void bar ()
23851 {
23852 int arr[] = { vals... };
23853 }
23855 If the array has no length and has an initializer, it must be that
23856 we couldn't determine its length in cp_complete_array_type because
23857 it is dependent. */
23865 /* A function or variable template-id is type-dependent if it has any
23866 dependent template arguments. Note that we only consider the innermost
23867 template arguments here, since those are the ones that come from the
23868 template-id; the template arguments for the enclosing class do not make it
23869 type-dependent, they only make a member function value-dependent. */
23874 && (any_dependent_template_arguments_p
23878 /* Always dependent, on the number of arguments if nothing else. */
23883 {
23888 {
23894 }
23895 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
23900 {
23905 }
23908 {
23915 }
23921 {
23925 }
23927 }
23931 /* Dependent type attributes might not have made it from the decl to
23932 the type yet. */
23938 }
23940 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
23941 type-dependent if the expression refers to a member of the current
23942 instantiation and the type of the referenced member is dependent, or the
23943 class member access expression refers to a member of an unknown
23944 specialization.
23946 This function returns true if the OBJECT in such a class member access
23947 expression is of an unknown specialization. */
23949 bool
23951 {
23952 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
23953 dependent. */
23958 }
23960 /* walk_tree callback function for instantiation_dependent_expression_p,
23961 below. Returns non-zero if a dependent subexpression is found. */
23963 static tree
23966 {
23968 {
23969 /* We don't have to worry about decltype currently because decltype
23970 of an instantiation-dependent expr is a dependent type. This
23971 might change depending on the resolution of DR 1172. */
23974 }
23977 {
23978 /* Don't treat an argument list as dependent just because it has no
23979 TREE_TYPE. */
23987 /* Handle expressions with type operands. */
23992 {
23997 {
24000 else
24001 {
24004 }
24005 }
24007 }
24011 /* In a template, finish_class_member_access_expr creates a
24012 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
24013 type-dependent, so that we can check access control at
24014 instantiation time (PR 42277). See also Core issue 1273. */
24021 else
24024 /* Treat statement-expressions as dependent. */
24028 /* Treat requires-expressions as dependent. */
24033 /* Treat calls to function concepts as dependent. */
24039 /* And variable concepts. */
24046 }
24050 else
24052 }
24054 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
24055 sense defined by the ABI:
24057 "An expression is instantiation-dependent if it is type-dependent
24058 or value-dependent, or it has a subexpression that is type-dependent
24059 or value-dependent."
24061 Except don't actually check value-dependence for unevaluated expressions,
24062 because in sizeof(i) we don't care about the value of i. Checking
24063 type-dependence will in turn check value-dependence of array bounds/template
24064 arguments as needed. */
24066 bool
24068 {
24069 tree result;
24080 }
24082 /* As above, but also check value-dependence of the expression as a whole. */
24084 bool
24086 {
24089 }
24091 /* Like type_dependent_expression_p, but it also works while not processing
24092 a template definition, i.e. during substitution or mangling. */
24094 bool
24096 {
24102 }
24104 /* Returns TRUE if ARGS contains a type-dependent expression. */
24106 bool
24108 {
24110 tree arg;
24113 {
24116 }
24118 }
24120 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24121 expressions) contains any type-dependent expressions. */
24123 bool
24125 {
24131 }
24133 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24134 expressions) contains any value-dependent expressions. */
24136 bool
24138 {
24144 }
24146 /* Returns TRUE if the ARG (a template argument) is dependent. */
24148 bool
24150 {
24154 /* Assume a template argument that was wrongly written by the user
24155 is dependent. This is consistent with what
24156 any_dependent_template_arguments_p [that calls this function]
24157 does. */
24167 {
24170 /* A member template of a dependent class is not necessarily
24171 type-dependent, but it is a dependent template argument because it
24172 will be a member of an unknown specialization to that template. */
24175 }
24177 {
24181 {
24184 }
24187 }
24190 else
24193 }
24195 /* Returns true if ARGS (a collection of template arguments) contains
24196 any types that require structural equality testing. */
24198 bool
24200 {
24210 {
24213 {
24219 {
24220 /* Look inside the argument pack. */
24223 }
24226 {
24239 }
24240 }
24241 }
24244 }
24246 /* Returns true if ARGS (a collection of template arguments) contains
24247 any dependent arguments. */
24249 bool
24251 {
24261 {
24266 }
24269 }
24271 /* Returns TRUE if the template TMPL is type-dependent. */
24273 bool
24275 {
24277 {
24279 {
24283 }
24285 }
24287 /* Template template parameters are dependent. */
24291 /* So are names that have not been looked up. */
24295 }
24297 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
24299 bool
24301 {
24304 }
24306 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
24307 are dependent. */
24309 bool
24311 {
24318 {
24340 {
24344 }
24348 {
24352 {
24357 }
24358 }
24359 }
24362 }
24364 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
24365 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
24366 no such TYPE can be found. Note that this function peers inside
24367 uninstantiated templates and therefore should be used only in
24368 extremely limited situations. ONLY_CURRENT_P restricts this
24369 peering to the currently open classes hierarchy (which is required
24370 when comparing types). */
24372 tree
24374 {
24375 tree scope;
24376 tree name;
24377 tree decl;
24379 tree pushed_scope;
24380 tree result;
24385 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
24386 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
24387 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
24388 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
24389 identifier of the TYPENAME_TYPE anymore.
24390 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
24391 TYPENAME_TYPE instead, we avoid messing up with a possible
24392 typedef variant case. */
24395 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
24396 it first before we can figure out what NAME refers to. */
24398 {
24400 /* Given a class template A with a dependent base with nested type C,
24401 typedef typename A::C::C C will land us here, as trying to resolve
24402 the initial A::C leads to the local C typedef, which leads back to
24403 A::C::C. So we break the recursion now. */
24405 else
24407 }
24408 /* If we don't know what SCOPE refers to, then we cannot resolve the
24409 TYPENAME_TYPE. */
24412 /* If this is a typedef, we don't want to look inside (c++/11987). */
24415 /* If SCOPE isn't the template itself, it will not have a valid
24416 TYPE_FIELDS list. */
24418 /* scope is either the template itself or a compatible instantiation
24419 like X<T>, so look up the name in the original template. */
24421 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
24423 /* If scope has no fields, it can't be a current instantiation. Check this
24424 before currently_open_class to avoid infinite recursion (71515). */
24427 /* If the SCOPE is not the current instantiation, there's no reason
24428 to look inside it. */
24431 /* Enter the SCOPE so that name lookup will be resolved as if we
24432 were in the class definition. In particular, SCOPE will no
24433 longer be considered a dependent type. */
24435 /* Look up the declaration. */
24437 tf_warning_or_error);
24441 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
24442 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
24447 {
24451 }
24454 {
24455 tree tmpl;
24456 tree args;
24457 /* Obtain the template and the arguments. */
24460 /* Instantiate the template. */
24466 }
24468 /* Leave the SCOPE. */
24472 /* If we failed to resolve it, return the original typename. */
24476 /* If lookup found a typename type, resolve that too. */
24478 {
24479 /* Ill-formed programs can cause infinite recursion here, so we
24480 must catch that. */
24484 }
24486 /* Qualify the resulting type. */
24492 }
24494 /* EXPR is an expression which is not type-dependent. Return a proxy
24495 for EXPR that can be used to compute the types of larger
24496 expressions containing EXPR. */
24498 tree
24500 {
24501 tree inner_expr;
24503 /* When checking, try to get a constant value for all non-dependent
24504 expressions in order to expose bugs in *_dependent_expression_p
24505 and constexpr. This can affect code generation, see PR70704, so
24506 only do this for -fchecking=2. */
24509 /* Don't do this during nsdmi parsing as it can lead to
24510 unexpected recursive instantiations. */
24512 /* Don't do this during concept expansion either and for
24513 the same reason. */
24517 /* Preserve OVERLOADs; the functions must be available to resolve
24518 types. */
24529 /* There is no need to return a proxy for a variable. */
24532 /* Preserve string constants; conversions from string constants to
24533 "char *" are allowed, even though normally a "const char *"
24534 cannot be used to initialize a "char *". */
24537 /* Preserve void and arithmetic constants, as an optimization -- there is no
24538 reason to create a new node. */
24543 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
24544 There is at least one place where we want to know that a
24545 particular expression is a throw-expression: when checking a ?:
24546 expression, there are special rules if the second or third
24547 argument is a throw-expression. */
24551 /* Don't wrap an initializer list, we need to be able to look inside. */
24555 /* Don't wrap a dummy object, we need to be able to test for it. */
24574 /* If the type is unknown, it can't really be non-dependent */
24577 /* Otherwise, build a NON_DEPENDENT_EXPR. */
24579 }
24581 /* ARGS is a vector of expressions as arguments to a function call.
24582 Replace the arguments with equivalent non-dependent expressions.
24583 This modifies ARGS in place. */
24585 void
24587 {
24589 tree arg;
24592 {
24596 }
24597 }
24599 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
24600 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
24601 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
24603 static tree
24605 {
24619 }
24621 tree
24623 {
24625 }
24627 tree
24629 {
24631 }
24633 /* Return a C++17 deduction placeholder for class template TMPL. */
24635 tree
24637 {
24641 }
24643 /* Make a "constrained auto" type-specifier. This is an
24644 auto type with constraints that must be associated after
24645 deduction. The constraint is formed from the given
24646 CONC and its optional sequence of arguments, which are
24647 non-null if written as partial-concept-id. */
24649 tree
24651 {
24654 /* Build the constraint. */
24656 tree expr;
24659 else
24665 /* Our canonical type depends on the constraint. */
24668 /* Attach the constraint to the type declaration. */
24671 }
24673 /* Given type ARG, return std::initializer_list<ARG>. */
24675 static tree
24677 {
24678 tree std_init_list = namespace_binding
24680 tree argvec;
24682 {
24686 }
24691 }
24693 /* Replace auto in TYPE with std::initializer_list<auto>. */
24695 static tree
24697 {
24704 }
24706 /* Hash traits for hashing possibly constrained 'auto'
24707 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
24710 {
24713 };
24715 /* Hash the 'auto' T. */
24717 inline hashval_t
24719 {
24721 /* Matching constrained-type-specifiers denote the same template
24722 parameter, so hash the constraint. */
24724 else
24725 /* But unconstrained autos are all separate, so just hash the pointer. */
24727 }
24729 /* Compare two 'auto's. */
24733 {
24740 /* Two unconstrained autos are distinct. */
24745 }
24747 /* for_each_template_parm callback for extract_autos: if t is a (possibly
24748 constrained) auto, add it to the vector. */
24750 static int
24752 {
24755 {
24756 /* All the autos were built with index 0; fix that up now. */
24760 /* If this is a repeated constrained-type-specifier, use the index we
24761 chose before. */
24763 else
24764 {
24765 /* Otherwise this is new, so use the current count. */
24768 }
24770 }
24772 /* Always keep walking. */
24774 }
24776 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
24777 says they can appear anywhere in the type. */
24779 static tree
24781 {
24790 {
24795 }
24798 }
24800 /* The stem for deduction guide names. */
24803 /* Return the name for a deduction guide for class template TMPL. */
24805 tree
24807 {
24818 }
24820 /* True if NAME is the name of a deduction guide. */
24822 bool
24824 {
24828 }
24830 /* True if FN is a deduction guide. */
24832 bool
24834 {
24839 }
24841 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
24842 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
24843 template parameter types. Note that the handling of template template
24844 parameters relies on current_template_parms being set appropriately for the
24845 new template. */
24847 static tree
24850 {
24853 tree newtype;
24856 {
24863 }
24864 else
24868 tree newdecl
24873 tree newidx;
24876 {
24884 {
24889 // First create a copy (ttargs) of tsubst_args with an
24890 // additional level for the template template parameter's own
24891 // template parameters (ttparms).
24892 tree ttparms = (INNERMOST_TEMPLATE_PARMS
24900 // Substitute ttargs into ttparms to fix references to
24901 // other template parameters.
24903 complain);
24904 // Now substitute again with args based on tparms, to reduce
24905 // the level of the ttparms.
24908 complain);
24909 // Finally, tack the adjusted parms onto tparms.
24911 current_template_parms);
24913 }
24914 }
24915 else
24916 {
24918 tree newconst
24928 }
24933 }
24935 /* Returns a C++17 class deduction guide template based on the constructor
24936 CTOR. */
24938 static tree
24940 {
24944 tree fn_tmpl;
24946 {
24949 }
24950 else
24954 /* If type is a member class template, DECL_TI_ARGS (ctor) will have fully
24955 specialized args for the enclosing class. Strip those off, as the
24956 deduction guide won't have those template parameters. */
24959 /* Discard the 'this' parameter. */
24965 {
24966 /* For a member template constructor, we need to flatten the two template
24967 parameter lists into one, and then adjust the function signature
24968 accordingly. This gets...complicated. */
24972 /* For a member template we should have two levels of parms/args, one for
24973 the class and one for the constructor. We stripped specialized args
24974 for further enclosing classes above. */
24978 /* Template args for translating references to the two-level template
24979 parameters into references to the one-level template parameters we are
24980 creating. */
24985 /* Template parms for the constructor template. */
24988 /* Template parms for the class template. */
24992 /* Template parms for the deduction guide start as a copy of the template
24993 parms for the class. We set current_template_parms for
24994 lookup_template_class_1. */
25000 /* Now we need to rewrite the constructor parms to append them to the
25001 class parms. */
25003 {
25018 }
25020 /* Now we have a final set of template parms to substitute into the
25021 function signature. */
25031 }
25032 else
25033 {
25034 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
25038 }
25042 FUNCTION_DECL,
25057 }
25059 /* Deduce template arguments for the class template placeholder PTYPE for
25060 template TMPL based on the initializer INIT, and return the resulting
25061 type. */
25063 static tree
25065 tsubst_flags_t complain)
25066 {
25068 {
25069 /* We should have handled this in the caller. */
25075 }
25084 else
25088 {
25089 /* First try to deduce directly, since we don't have implicitly-declared
25090 constructors yet. */
25099 }
25111 {
25114 }
25117 // FIXME cache artificial deduction guides
25119 {
25123 }
25126 {
25130 }
25132 /* Prune explicit deduction guides in copy-initialization context. */
25135 {
25141 {
25144 {
25148 }
25151 {
25153 " of %qT, as it has no non-explicit deduction guides or "
25156 }
25157 }
25158 }
25162 tf_decltype);
25165 {
25172 }
25178 }
25180 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25181 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
25183 tree
25185 {
25187 tf_warning_or_error,
25188 adc_unspecified);
25189 }
25191 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25192 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
25193 The CONTEXT determines the context in which auto deduction is performed
25194 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
25195 OUTER_TARGS are used during template argument deduction
25196 (context == adc_unify) to properly substitute the result, and is ignored
25197 in other contexts.
25199 For partial-concept-ids, extra args may be appended to the list of deduced
25200 template arguments prior to determining constraint satisfaction. */
25202 tree
25206 {
25207 tree targs;
25214 /* Defining a subset of type-dependent expressions that we can deduce
25215 from ahead of time isn't worth the trouble. */
25219 /* C++17 class template argument deduction. */
25223 /* Nothing we can do with this, even in deduction context. */
25226 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
25227 with either a new invented type template parameter U or, if the
25228 initializer is a braced-init-list (8.5.4), with
25229 std::initializer_list<U>. */
25231 {
25236 else
25237 {
25239 {
25243 "for deduction to %<std::initializer_list%>, use copy-"
25245 }
25247 }
25248 }
25259 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
25260 and initializer has array type, deduce cv-qualified array type. */
25262 complain);
25264 {
25273 {
25277 }
25278 }
25279 else
25280 {
25282 tree tparms;
25286 else
25287 {
25291 }
25298 {
25300 /* Try again at instantiation time. */
25304 /* If type is error_mark_node a diagnostic must have been
25305 emitted by now. Also, having a mention to '<type error>'
25306 in the diagnostic is not really useful to the user. */
25307 {
25311 else
25316 }
25318 }
25319 }
25321 /* Check any placeholder constraints against the deduced type. */
25324 {
25325 /* Use the deduced type to check the associated constraints. If we
25326 have a partial-concept-id, rebuild the argument list so that
25327 we check using the extra arguments. */
25331 {
25334 }
25335 else
25338 {
25340 {
25342 {
25360 }
25362 }
25364 }
25365 }
25371 }
25373 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
25374 result. */
25376 tree
25378 {
25380 {
25386 /* In an abbreviated function template we didn't know we were dealing
25387 with a function template when we saw the auto return type, so update
25388 it to have the correct level. */
25390 }
25392 }
25394 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
25395 'decltype(auto)' or a deduced class template. */
25397 bool
25399 {
25405 else
25407 }
25409 /* for_each_template_parm callback for type_uses_auto. */
25411 int
25413 {
25415 }
25417 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
25418 a use of `auto'. Returns NULL_TREE otherwise. */
25420 tree
25422 {
25426 {
25427 /* The Concepts TS allows multiple autos in one type-specifier; just
25428 return the first one we find, do_auto_deduction will collect all of
25429 them. */
25433 else
25435 }
25436 else
25438 }
25440 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto',
25441 'decltype(auto)' or a concept. */
25443 bool
25445 {
25447 }
25449 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing a generic type (`auto' or
25450 a concept identifier) iff TYPE contains a use of a generic type. Returns
25451 NULL_TREE otherwise. */
25453 tree
25455 {
25457 }
25460 /* For a given template T, return the vector of typedefs referenced
25461 in T for which access check is needed at T instantiation time.
25462 T is either a FUNCTION_DECL or a RECORD_TYPE.
25463 Those typedefs were added to T by the function
25464 append_type_to_template_for_access_check. */
25468 {
25469 tree ti;
25480 {
25485 }
25488 }
25490 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
25491 tied to T. That list of typedefs will be access checked at
25492 T instantiation time.
25493 T is either a FUNCTION_DECL or a RECORD_TYPE.
25494 TYPE_DECL is a TYPE_DECL node representing a typedef.
25495 SCOPE is the scope through which TYPE_DECL is accessed.
25496 LOCATION is the location of the usage point of TYPE_DECL.
25498 This function is a subroutine of
25499 append_type_to_template_for_access_check. */
25501 static void
25503 tree type_decl,
25504 tree scope,
25505 location_t location)
25506 {
25507 qualified_typedef_usage_t typedef_usage;
25508 tree ti;
25515 && type_decl
25529 }
25531 /* Append TYPE_DECL to the template TEMPL.
25532 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
25533 At TEMPL instanciation time, TYPE_DECL will be checked to see
25534 if it can be accessed through SCOPE.
25535 LOCATION is the location of the usage point of TYPE_DECL.
25537 e.g. consider the following code snippet:
25539 class C
25540 {
25541 typedef int myint;
25542 };
25544 template<class U> struct S
25545 {
25546 C::myint mi; // <-- usage point of the typedef C::myint
25547 };
25549 S<char> s;
25551 At S<char> instantiation time, we need to check the access of C::myint
25552 In other words, we need to check the access of the myint typedef through
25553 the C scope. For that purpose, this function will add the myint typedef
25554 and the scope C through which its being accessed to a list of typedefs
25555 tied to the template S. That list will be walked at template instantiation
25556 time and access check performed on each typedefs it contains.
25557 Note that this particular code snippet should yield an error because
25558 myint is private to C. */
25560 void
25562 tree type_decl,
25563 tree scope,
25564 location_t location)
25565 {
25571 /* Make sure we don't append the type to the template twice. */
25578 }
25580 /* Convert the generic type parameters in PARM that match the types given in the
25581 range [START_IDX, END_IDX) from the current_template_parms into generic type
25582 packs. */
25584 tree
25586 {
25597 {
25598 /* Create a distinct parameter pack type from the current parm and add it
25599 to the replacement args to tsubst below into the generic function
25600 parameter. */
25615 }
25621 /* If there are more levels then build up the replacement with the outer
25622 template parms. */
25626 replacement);
25629 }
25631 /* Entries in the decl_constraint hash table. */
25633 {
25634 tree decl;
25635 tree ci;
25636 };
25638 /* Hashing function and equality for constraint entries. */
25640 {
25642 {
25644 }
25647 {
25649 }
25650 };
25652 /* A mapping from declarations to constraint information. Note that
25653 both templates and their underlying declarations are mapped to the
25654 same constraint information.
25656 FIXME: This is defined in pt.c because garbage collection
25657 code is not being generated for constraint.cc. */
25661 /* Returns the template constraints of declaration T. If T is not
25662 constrained, return NULL_TREE. Note that T must be non-null. */
25664 tree
25666 {
25677 else
25679 }
25681 /* Associate the given constraint information CI with the declaration
25682 T. If T is a template, then the constraints are associated with
25683 its underlying declaration. Don't build associations if CI is
25684 NULL_TREE. */
25686 void
25688 {
25700 }
25702 /* Remove the associated constraints of the declaration T. */
25704 void
25706 {
25715 }
25717 /* Memoized satisfaction results for declarations. This
25718 maps the pair (constraint_info, arguments) to the result computed
25719 by constraints_satisfied_p. */
25722 {
25723 tree ci;
25724 tree args;
25725 tree result;
25726 };
25728 /* Hashing function and equality for constraint entries. */
25731 {
25733 {
25736 }
25739 {
25741 }
25742 };
25744 /* Memoized satisfaction results for concept checks. */
25747 {
25748 tree tmpl;
25749 tree args;
25750 tree result;
25751 };
25753 /* Hashing function and equality for constraint entries. */
25756 {
25758 {
25760 }
25763 {
25768 }
25769 };
25774 /* Search for a memoized satisfaction result. Returns one of the
25775 truth value nodes if previously memoized, or NULL_TREE otherwise. */
25777 tree
25779 {
25784 else
25786 }
25788 /* Memoize the result of a satisfication test. Returns the saved result. */
25790 tree
25792 {
25799 }
25801 /* Search for a memoized satisfaction result for a concept. */
25803 tree
25805 {
25810 else
25812 }
25814 /* Memoize the result of a concept check. Returns the saved result. */
25816 tree
25818 {
25825 }
25829 /* Returns a prior concept specialization. This returns the substituted
25830 and normalized constraints defined by the concept. */
25832 tree
25834 {
25839 else
25841 }
25843 /* Save a concept expansion for later. */
25845 tree
25847 {
25854 }
25856 static hashval_t
25858 {
25867 }
25869 /* Compare the constraints of two subsumption entries. The LEFT1 and
25870 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
25871 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
25873 static bool
25875 {
25883 }
25885 /* Key/value pair for learning and memoizing subsumption results. This
25886 associates a pair of check constraints (including arguments) with
25887 a boolean value indicating the result. */
25890 {
25891 tree t1;
25892 tree t2;
25894 };
25896 /* Hashing function and equality for constraint entries. */
25899 {
25901 {
25903 }
25906 {
25911 }
25912 };
25916 /* Search for a previously cached subsumption result. */
25920 {
25925 else
25927 }
25929 /* Save a subsumption result. */
25931 bool
25933 {
25940 }
25942 /* Set up the hash table for constraint association. */
25944 void
25946 {
25955 }
25957 /* Set up the hash tables for template instantiations. */
25959 void
25961 {
25964 }
25966 /* Print stats about the template hash tables for -fstats. */
25968 void
25970 {
25979 }