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1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2016 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. */
3609 {
3610 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3611 type_pack_expansion_p to false so that any placeholders
3612 within the expression don't get marked as parameter packs. */
3620 }
3624 }
3627 }
3629 /* Determines if the expression or type T uses any parameter packs. */
3630 bool
3632 {
3641 }
3643 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3644 representation a base-class initializer into a parameter pack
3645 expansion. If all goes well, the resulting node will be an
3646 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3647 respectively. */
3648 tree
3650 {
3651 tree result;
3660 {
3661 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3662 class initializer. In this case, the TREE_PURPOSE will be a
3663 _TYPE node (representing the base class expansion we're
3664 initializing) and the TREE_VALUE will be a TREE_LIST
3665 containing the initialization arguments.
3667 The resulting expansion looks somewhat different from most
3668 expansions. Rather than returning just one _EXPANSION, we
3669 return a TREE_LIST whose TREE_PURPOSE is a
3670 TYPE_PACK_EXPANSION containing the bases that will be
3671 initialized. The TREE_VALUE will be identical to the
3672 original TREE_VALUE, which is a list of arguments that will
3673 be passed to each base. We do not introduce any new pack
3674 expansion nodes into the TREE_VALUE (although it is possible
3675 that some already exist), because the TREE_PURPOSE and
3676 TREE_VALUE all need to be expanded together with the same
3677 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3678 resulting TREE_PURPOSE will mention the parameter packs in
3679 both the bases and the arguments to the bases. */
3680 tree purpose;
3681 tree value;
3684 /* Determine which parameter packs will be used by the base
3685 class expansion. */
3694 {
3698 }
3701 {
3702 /* Collect the sets of parameter packs used in each of the
3703 initialization arguments. */
3705 {
3706 /* Determine which parameter packs will be expanded in this
3707 argument. */
3710 }
3711 }
3715 /* Create the pack expansion type for the base type. */
3720 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3721 they will rarely be compared to anything. */
3725 }
3730 /* Build the PACK_EXPANSION_* node. */
3731 result = for_types
3736 {
3737 /* Propagate type and const-expression information. */
3740 /* Mark this read now, since the expansion might be length 0. */
3742 }
3743 else
3744 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3745 they will rarely be compared to anything. */
3748 /* Determine which parameter packs will be expanded. */
3755 /* Make sure we found some parameter packs. */
3757 {
3760 else
3763 }
3769 }
3771 /* Checks T for any "bare" parameter packs, which have not yet been
3772 expanded, and issues an error if any are found. This operation can
3773 only be done on full expressions or types (e.g., an expression
3774 statement, "if" condition, etc.), because we could have expressions like:
3776 foo(f(g(h(args)))...)
3778 where "args" is a parameter pack. check_for_bare_parameter_packs
3779 should not be called for the subexpressions args, h(args),
3780 g(h(args)), or f(g(h(args))), because we would produce erroneous
3781 error messages.
3783 Returns TRUE and emits an error if there were bare parameter packs,
3784 returns FALSE otherwise. */
3785 bool
3787 {
3804 {
3808 {
3817 else
3822 else
3826 }
3829 }
3832 }
3834 /* Expand any parameter packs that occur in the template arguments in
3835 ARGS. */
3836 tree
3838 {
3844 /* First, determine if we need to expand anything, and the number of
3845 slots we'll need. */
3847 {
3852 {
3856 else
3858 }
3859 else
3860 {
3862 num_result_args++;
3863 }
3864 }
3866 /* If no expansion is necessary, we're done. */
3870 /* Expand arguments. */
3873 non_default_args_count =
3876 {
3879 {
3886 }
3887 else
3888 {
3891 }
3892 }
3896 }
3898 /* Checks if DECL shadows a template parameter.
3900 [temp.local]: A template-parameter shall not be redeclared within its
3901 scope (including nested scopes).
3903 Emits an error and returns TRUE if the DECL shadows a parameter,
3904 returns FALSE otherwise. */
3906 bool
3908 {
3909 tree olddecl;
3911 /* If we're not in a template, we can't possibly shadow a template
3912 parameter. */
3916 /* Figure out what we're shadowing. */
3921 /* If there's no previous binding for this name, we're not shadowing
3922 anything, let alone a template parameter. */
3926 /* If we're not shadowing a template parameter, we're done. Note
3927 that OLDDECL might be an OVERLOAD (or perhaps even an
3928 ERROR_MARK), so we can't just blithely assume it to be a _DECL
3929 node. */
3933 /* We check for decl != olddecl to avoid bogus errors for using a
3934 name inside a class. We check TPFI to avoid duplicate errors for
3935 inline member templates. */
3941 /* Don't complain about the injected class name, as we've already
3942 complained about the class itself. */
3949 else
3954 }
3956 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
3957 ORIG_LEVEL, DECL, and TYPE. */
3959 static tree
3963 tree decl,
3964 tree type)
3965 {
3976 }
3978 /* Find the canonical type parameter for the given template type
3979 parameter. Returns the canonical type parameter, which may be TYPE
3980 if no such parameter existed. */
3982 static tree
3984 {
3985 tree list;
3999 else
4000 {
4005 }
4006 }
4008 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4009 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4010 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4011 new one is created. */
4013 static tree
4015 tsubst_flags_t complain)
4016 {
4021 {
4040 /* Template template parameters need this. */
4042 {
4049 }
4050 }
4053 }
4055 /* Process information from new template parameter PARM and append it
4056 to the LIST being built. This new parameter is a non-type
4057 parameter iff IS_NON_TYPE is true. This new parameter is a
4058 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4059 is in PARM_LOC. */
4061 tree
4064 {
4073 {
4077 {
4081 else
4083 }
4086 }
4089 {
4095 {
4096 /* [temp.param]
4098 The top-level cv-qualifiers on the template-parameter are
4099 ignored when determining its type. */
4104 && !is_parameter_pack
4105 /* If we're in a nested template parameter list, the template
4106 template parameter could be a parameter pack. */
4108 {
4109 /* This template parameter is not a parameter pack, but it
4110 should be. Complain about "bare" parameter packs. */
4113 /* Recover by calling this a parameter pack. */
4115 }
4116 }
4118 /* A template parameter is not modifiable. */
4127 processing_template_decl,
4132 }
4133 else
4134 {
4135 tree t;
4139 {
4141 /* This is for distinguishing between real templates and template
4142 template parameters */
4146 }
4147 else
4148 {
4150 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4153 }
4160 processing_template_decl,
4164 }
4168 /* Build requirements for the type/template parameter.
4169 This must be done after SET_DECL_TEMPLATE_PARM_P or
4170 process_template_parm could fail. */
4175 /* Build the parameter node linking the parameter declaration,
4176 its default argument (if any), and its constraints (if any). */
4181 }
4183 /* The end of a template parameter list has been reached. Process the
4184 tree list into a parameter vector, converting each parameter into a more
4185 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4186 as PARM_DECLs. */
4188 tree
4190 {
4195 /* Pop the dummy parameter level and add the real one. */
4198 current_template_parms
4203 {
4207 }
4212 }
4214 // Explicitly indicate the end of the template parameter list. We assume
4215 // that the current template parameters have been constructed and/or
4216 // managed explicitly, as when creating new template template parameters
4217 // from a shorthand constraint.
4218 void
4220 {
4222 }
4224 /* end_template_decl is called after a template declaration is seen. */
4226 void
4228 {
4234 /* This matches the pushlevel in begin_template_parm_list. */
4239 }
4241 /* Takes a TREE_LIST representing a template parameter and convert it
4242 into an argument suitable to be passed to the type substitution
4243 functions. Note that If the TREE_LIST contains an error_mark
4244 node, the returned argument is error_mark_node. */
4246 tree
4248 {
4261 {
4265 {
4266 /* Turn this argument into a TYPE_ARGUMENT_PACK
4267 with a single element, which expands T. */
4276 }
4277 }
4278 else
4279 {
4283 {
4284 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4285 with a single element, which expands T. */
4297 }
4298 else
4300 }
4302 }
4304 /* Given a single level of template parameters (a TREE_VEC), return it
4305 as a set of template arguments. */
4307 static tree
4309 {
4319 }
4321 /* Given a set of template parameters, return them as a set of template
4322 arguments. The template parameters are represented as a TREE_VEC, in
4323 the form documented in cp-tree.h for template arguments. */
4325 static tree
4327 {
4328 tree header;
4333 /* If there is only one level of template parameters, we do not
4334 create a TREE_VEC of TREE_VECs. Instead, we return a single
4335 TREE_VEC containing the arguments. */
4340 {
4345 else
4347 }
4350 }
4352 /* Within the declaration of a template, return the currently active
4353 template parameters as an argument TREE_VEC. */
4355 static tree
4357 {
4359 }
4361 /* Update the declared TYPE by doing any lookups which were thought to be
4362 dependent, but are not now that we know the SCOPE of the declarator. */
4364 tree
4366 {
4377 /* Don't bother building up the args in this case. */
4379 {
4380 /* tsubst in the args corresponding to the template parameters,
4381 including auto if present. Most things will be unchanged, but
4382 make_typename_type and tsubst_qualified_id will resolve
4383 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4386 tree pushed;
4388 {
4392 }
4397 }
4403 {
4406 else
4408 }
4410 }
4412 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4413 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4414 the new template is a member template. */
4416 tree
4418 {
4426 }
4428 struct template_parm_data
4429 {
4430 /* The level of the template parameters we are currently
4431 processing. */
4434 /* The index of the specialization argument we are currently
4435 processing. */
4438 /* An array whose size is the number of template parameters. The
4439 elements are nonzero if the parameter has been used in any one
4440 of the arguments processed so far. */
4443 /* An array whose size is the number of template arguments. The
4444 elements are nonzero if the argument makes use of template
4445 parameters of this level. */
4447 };
4449 /* Subroutine of push_template_decl used to see if each template
4450 parameter in a partial specialization is used in the explicit
4451 argument list. If T is of the LEVEL given in DATA (which is
4452 treated as a template_parm_data*), then DATA->PARMS is marked
4453 appropriately. */
4455 static int
4457 {
4465 {
4468 }
4470 /* Return zero so that for_each_template_parm will continue the
4471 traversal of the tree; we want to mark *every* template parm. */
4473 }
4475 /* Process the partial specialization DECL. */
4477 static tree
4479 {
4486 tree inner_parms;
4487 tree inst;
4497 /* A concept cannot be specialized. */
4499 {
4502 }
4507 /* We check that each of the template parameters given in the
4508 partial specialization is used in the argument list to the
4509 specialization. For example:
4511 template <class T> struct S;
4512 template <class T> struct S<T*>;
4514 The second declaration is OK because `T*' uses the template
4515 parameter T, whereas
4517 template <class T> struct S<int>;
4519 is no good. Even trickier is:
4521 template <class T>
4522 struct S1
4523 {
4524 template <class U>
4525 struct S2;
4526 template <class U>
4527 struct S2<T>;
4528 };
4530 The S2<T> declaration is actually invalid; it is a
4531 full-specialization. Of course,
4533 template <class U>
4534 struct S2<T (*)(U)>;
4536 or some such would have been OK. */
4544 {
4549 NULL,
4551 }
4554 {
4555 /* One of the template parms was not used in a deduced context in the
4556 specialization. */
4558 {
4562 }
4566 }
4571 /* [temp.class.spec]
4573 The argument list of the specialization shall not be identical to
4574 the implicit argument list of the primary template. */
4575 tree main_args
4578 && (!flag_concepts
4581 {
4585 else
4589 }
4591 /* A partial specialization that replaces multiple parameters of the
4592 primary template with a pack expansion is less specialized for those
4593 parameters. */
4595 {
4597 "primary template because it replaces multiple parameters "
4601 }
4603 /* [temp.class.spec]
4605 A partially specialized non-type argument expression shall not
4606 involve template parameters of the partial specialization except
4607 when the argument expression is a simple identifier.
4609 The type of a template parameter corresponding to a specialized
4610 non-type argument shall not be dependent on a parameter of the
4611 specialization.
4613 Also, we verify that pack expansions only occur at the
4614 end of the argument list. */
4618 {
4625 {
4626 /* Extract the arguments from the argument pack. We'll be
4627 iterating over these in the following loop. */
4630 }
4633 {
4635 /* Get the Jth argument in the parameter pack. */
4639 {
4640 /* Pack expansions must come at the end of the
4641 argument list. */
4644 {
4648 else
4651 }
4652 }
4655 /* We only care about the pattern. */
4661 /* This next two lines are the `argument expression is not just a
4662 simple identifier' condition and also the `specialized
4663 non-type argument' bit. */
4667 {
4671 arg);
4672 else
4673 {
4674 /* Look at the corresponding template parameter,
4675 marking which template parameters its type depends
4676 upon. */
4680 {
4681 /* We haven't yet initialized TPD2. Do so now. */
4683 /* The number of parameters here is the number in the
4684 main template, which, as checked in the assertion
4685 above, is NARGS. */
4689 }
4691 /* Mark the template parameters. But this time, we're
4692 looking for the template parameters of the main
4693 template, not in the specialization. */
4700 NULL,
4704 {
4705 /* The type depended on some template parameters.
4706 If they are fully specialized in the
4707 specialization, that's OK. */
4716 "type %qT of template argument %qE depends "
4718 "type %qT of template argument %qE depends "
4720 type,
4721 arg);
4722 }
4723 }
4724 }
4725 }
4726 }
4728 /* We should only get here once. */
4732 // Build the template decl.
4742 /* We didn't register this in check_explicit_specialization so we could
4743 wait until the constraints were set. */
4745 else
4755 {
4761 {
4769 "declaration of %qD ambiguates earlier template "
4773 "partial specialization of %qD after instantiation "
4775 }
4776 }
4779 }
4781 /* PARM is a template parameter of some form; return the corresponding
4782 TEMPLATE_PARM_INDEX. */
4784 static tree
4786 {
4799 }
4801 /* Subroutine of fixed_parameter_pack_p below. Look for any template
4802 parameter packs used by the template parameter PARM. */
4804 static void
4806 {
4807 /* A type parm can't refer to another parm. */
4811 {
4815 }
4822 }
4824 /* PARM is a template parameter pack. Return any parameter packs used in
4825 its type or the type of any of its template parameters. If there are
4826 any such packs, it will be instantiated into a fixed template parameter
4827 list by partial instantiation rather than be fully deduced. */
4829 tree
4831 {
4832 /* This can only be true in a member template. */
4835 /* This can only be true for a parameter pack. */
4838 /* A type parm can't refer to another parm. */
4852 }
4854 /* Check that a template declaration's use of default arguments and
4855 parameter packs is not invalid. Here, PARMS are the template
4856 parameters. IS_PRIMARY is true if DECL is the thing declared by
4857 a primary template. IS_PARTIAL is true if DECL is a partial
4858 specialization.
4860 IS_FRIEND_DECL is nonzero if DECL is a friend function template
4861 declaration (but not a definition); 1 indicates a declaration, 2
4862 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4863 emitted for extraneous default arguments.
4865 Returns TRUE if there were no errors found, FALSE otherwise. */
4867 bool
4870 {
4873 tree parm_level;
4876 /* [temp.param]
4878 A default template-argument shall not be specified in a
4879 function template declaration or a function template definition, nor
4880 in the template-parameter-list of the definition of a member of a
4881 class template. */
4885 /* You can't have a function template declaration in a local
4886 scope, nor you can you define a member of a class template in a
4887 local scope. */
4895 /* A lambda doesn't have an explicit declaration; don't complain
4896 about the parms of the enclosing class. */
4903 /* If this is either a friend defined in the scope of the class
4904 or a member function. */
4910 /* And, if it was a member function, it really was defined in
4911 the scope of the class. */
4914 /* We already checked these parameters when the template was
4915 declared, so there's no need to do it again now. This function
4916 was defined in class scope, but we're processing its body now
4917 that the class is complete. */
4920 /* Core issue 226 (C++0x only): the following only applies to class
4921 templates. */
4924 {
4925 /* [temp.param]
4927 If a template-parameter has a default template-argument, all
4928 subsequent template-parameters shall have a default
4929 template-argument supplied. */
4931 {
4938 {
4948 {
4950 /* For better subsequent error-recovery, we indicate that
4951 there should have been a default argument. */
4954 }
4956 && !is_friend_decl
4957 /* Don't complain about an enclosing partial
4958 specialization. */
4963 /* A fixed parameter pack will be partially
4964 instantiated into a fixed length list. */
4966 {
4967 /* A primary class template can only have one
4968 parameter pack, at the end of the template
4969 parameter list. */
4977 }
4978 }
4979 }
4980 }
4983 || is_partial
4984 || !is_primary
4986 /* For an ordinary class template, default template arguments are
4987 allowed at the innermost level, e.g.:
4988 template <class T = int>
4989 struct S {};
4990 but, in a partial specialization, they're not allowed even
4991 there, as we have in [temp.class.spec]:
4993 The template parameter list of a specialization shall not
4994 contain default template argument values.
4996 So, for a partial specialization, or for a function template
4997 (in C++98/C++03), we look at all of them. */
4998 ;
4999 else
5000 /* But, for a primary class template that is not a partial
5001 specialization we look at all template parameters except the
5002 innermost ones. */
5005 /* Figure out what error message to issue. */
5020 else
5021 /* Per [temp.param]/9, "A default template-argument shall not be
5022 specified in the template-parameter-lists of the definition of
5023 a member of a class template that appears outside of the member's
5024 class.", thus if we aren't handling a member of a class template
5025 there is no need to examine the parameters. */
5029 /* If we're inside a class definition, there's no need to
5030 examine the parameters to the class itself. On the one
5031 hand, they will be checked when the class is defined, and,
5032 on the other, default arguments are valid in things like:
5033 template <class T = double>
5034 struct S { template <class U> void f(U); };
5035 Here the default argument for `S' has no bearing on the
5036 declaration of `f'. */
5038 else
5039 /* Check everything. */
5045 {
5052 {
5057 {
5059 {
5066 }
5068 /* Clear out the default argument so that we are not
5069 confused later. */
5071 }
5072 }
5074 /* At this point, if we're still interested in issuing messages,
5075 they must apply to classes surrounding the object declared. */
5079 }
5082 }
5084 /* Worker for push_template_decl_real, called via
5085 for_each_template_parm. DATA is really an int, indicating the
5086 level of the parameters we are interested in. If T is a template
5087 parameter of that level, return nonzero. */
5089 static int
5091 {
5097 else
5100 }
5102 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5103 DATA is really an int, indicating the innermost outer level of parameters.
5104 If T is a template parameter of that level or further out, return
5105 nonzero. */
5107 static int
5109 {
5115 else
5118 }
5120 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5121 parameters given by current_template_args, or reuses a
5122 previously existing one, if appropriate. Returns the DECL, or an
5123 equivalent one, if it is replaced via a call to duplicate_decls.
5125 If IS_FRIEND is true, DECL is a friend declaration. */
5127 tree
5129 {
5130 tree tmpl;
5131 tree args;
5132 tree info;
5133 tree ctx;
5137 /* True if the template is a member template, in the sense of
5138 [temp.mem]. */
5144 /* See if this is a partial specialization. */
5157 /* For a friend, we want the context of the friend function, not
5158 the type of which it is a friend. */
5162 /* In the case of a virtual function, we want the class in which
5163 it is defined. */
5165 else
5166 /* Otherwise, if we're currently defining some class, the DECL
5167 is assumed to be a member of the class. */
5176 /* See if this is a primary template. */
5179 /* A friend template that specifies a class context, i.e.
5180 template <typename T> friend void A<T>::f();
5181 is not primary. */
5186 else
5190 {
5197 {
5200 }
5202 {
5204 {
5207 }
5209 {
5210 /* [temp.mem]
5212 A destructor shall not be a member template. */
5215 }
5222 {
5223 /* [basic.stc.dynamic.allocation]
5225 An allocation function can be a function
5226 template. ... Template allocation functions shall
5227 have two or more parameters. */
5230 }
5231 }
5237 /* alias-declaration */
5241 else
5242 {
5245 }
5246 }
5248 /* Check to see that the rules regarding the use of default
5249 arguments are not being violated. */
5253 /* Ensure that there are no parameter packs in the type of this
5254 declaration that have not been expanded. */
5256 {
5257 /* Check each of the arguments individually to see if there are
5258 any bare parameter packs. */
5264 {
5267 {
5268 /* This is a PARM_DECL that contains unexpanded parameter
5269 packs. We have already complained about this in the
5270 check_for_bare_parameter_packs call, so just replace
5271 these types with ERROR_MARK_NODE. */
5274 }
5278 }
5280 /* Check for bare parameter packs in the return type and the
5281 exception specifiers. */
5283 /* Errors were already issued, set return type to int
5284 as the frontend doesn't expect error_mark_node as
5285 the return type. */
5289 }
5294 {
5297 }
5310 {
5315 /* If DECL is a TYPE_DECL for a class-template, then there won't
5316 be DECL_LANG_SPECIFIC. The information equivalent to
5317 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5321 {
5322 /* Since a template declaration already existed for this
5323 class-type, we must be redeclaring it here. Make sure
5324 that the redeclaration is valid. */
5326 current_template_parms,
5328 /* We don't need to create a new TEMPLATE_DECL; just use the
5329 one we already had. */
5331 }
5332 else
5333 {
5335 member_template_p);
5340 {
5341 /* A specialization of a member template of a template
5342 class. */
5346 }
5347 }
5348 }
5349 else
5350 {
5356 {
5359 }
5367 {
5368 tree new_tmpl;
5370 /* The declaration is a specialization of a member
5371 template, declared outside the class. Therefore, the
5372 innermost template arguments will be NULL, so we
5373 replace them with the arguments determined by the
5374 earlier call to check_explicit_specialization. */
5377 new_tmpl
5379 member_template_p);
5389 args,
5392 }
5394 /* Make sure the template headers we got make sense. */
5399 {
5404 }
5405 else
5407 {
5412 {
5416 else
5420 /* Avoid crash in import_export_decl. */
5423 }
5428 /* Can happen in erroneous input. */
5430 else
5432 }
5434 /* Check that the parms are used in the appropriate qualifying scopes
5435 in the declarator. */
5439 {
5445 /* Avoid crash in import_export_decl. */
5448 }
5449 }
5454 /* Push template declarations for global functions and types. Note
5455 that we do not try to push a global template friend declared in a
5456 template class; such a thing may well depend on the template
5457 parameters of the class. */
5460 {
5465 /* Hide template friend classes that haven't been declared yet. */
5467 {
5470 }
5471 }
5474 {
5480 {
5483 /* It is a conversion operator. See if the type converted to
5484 depends on innermost template operands. */
5487 depth))
5489 }
5491 /* Give template template parms a DECL_CONTEXT of the template
5492 for which they are a parameter. */
5495 {
5499 }
5505 }
5507 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5508 back to its most general template. If TMPL is a specialization,
5509 ARGS may only have the innermost set of arguments. Add the missing
5510 argument levels if necessary. */
5518 else
5519 {
5524 }
5527 && !is_friend
5530 /* Set DECL_COMDAT on template instantiations; if we force
5531 them to be emitted by explicit instantiation or -frepo,
5532 mark_needed will tell cgraph to do the right thing. */
5536 }
5538 tree
5540 {
5542 }
5544 /* FN is an inheriting constructor that inherits from the constructor
5545 template INHERITED; turn FN into a constructor template with a matching
5546 template header. */
5548 tree
5550 {
5551 tree inner_parms
5554 tree parms
5565 }
5567 /* Called when a class template TYPE is redeclared with the indicated
5568 template PARMS, e.g.:
5570 template <class T> struct S;
5571 template <class T> struct S {}; */
5573 bool
5575 {
5576 tree tmpl;
5577 tree tmpl_parms;
5581 {
5584 }
5588 /* The type is nested in some template class. Nothing to worry
5589 about here; there are no new template parameters for the nested
5590 type. */
5594 {
5596 tmpl);
5598 }
5604 {
5614 }
5617 {
5618 tree tmpl_parm;
5619 tree parm;
5620 tree tmpl_default;
5621 tree parm_default;
5635 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5636 TEMPLATE_DECL. */
5646 {
5650 }
5653 {
5654 /* We have in [temp.param]:
5656 A template-parameter may not be given default arguments
5657 by two different declarations in the same scope. */
5662 }
5665 /* Update the previous template parameters (which are the ones
5666 that will really count) with the new default value. */
5669 /* Update the new parameters, too; they'll be used as the
5670 parameters for any members. */
5673 /* Give each template template parm in this redeclaration a
5674 DECL_CONTEXT of the template for which they are a parameter. */
5676 {
5679 }
5680 }
5682 // Cannot redeclare a class template with a different set of constraints.
5684 {
5689 }
5692 }
5694 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5695 to be used when the caller has already checked
5696 (processing_template_decl
5697 && !instantiation_dependent_expression_p (expr)
5698 && potential_constant_expression (expr))
5699 and cleared processing_template_decl. */
5701 tree
5703 {
5706 complain,
5710 }
5712 /* Simplify EXPR if it is a non-dependent expression. Returns the
5713 (possibly simplified) expression. */
5715 tree
5717 {
5721 /* If we're in a template, but EXPR isn't value dependent, simplify
5722 it. We're supposed to treat:
5724 template <typename T> void f(T[1 + 1]);
5725 template <typename T> void f(T[2]);
5727 as two declarations of the same function, for example. */
5730 {
5731 processing_template_decl_sentinel s;
5733 }
5735 }
5737 tree
5739 {
5741 }
5743 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
5744 an uninstantiated expression. */
5746 tree
5748 {
5752 {
5755 else
5756 {
5757 processing_template_decl_sentinel s;
5759 }
5760 }
5762 }
5764 /* True iff T is a specialization of a variable template. */
5766 bool
5768 {
5773 }
5775 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5776 template declaration, or a TYPE_DECL for an alias declaration. */
5778 bool
5780 {
5788 }
5790 /* Return TRUE iff T is a specialization of an alias template. */
5792 bool
5794 {
5795 /* It's an alias template specialization if it's an alias and its
5796 TYPE_NAME is a specialization of a primary template. */
5802 }
5804 /* An alias template is complex from a SFINAE perspective if a template-id
5805 using that alias can be ill-formed when the expansion is not, as with
5806 the void_t template. We determine this by checking whether the
5807 expansion for the alias template uses all its template parameters. */
5809 struct uses_all_template_parms_data
5810 {
5813 };
5815 static int
5817 {
5825 }
5827 static bool
5829 {
5844 }
5846 /* Return TRUE iff T is a specialization of a complex alias template with
5847 dependent template-arguments. */
5849 bool
5851 {
5864 }
5866 /* Return the number of innermost template parameters in TMPL. */
5868 static int
5870 {
5873 }
5875 /* Return either TMPL or another template that it is equivalent to under DR
5876 1286: An alias that just changes the name of a template is equivalent to
5877 the other template. */
5879 static tree
5881 {
5884 {
5885 /* Determine if the alias is equivalent to an underlying template. */
5897 tree alias_args = INNERMOST_TEMPLATE_ARGS
5902 /* Alias is equivalent. Strip it and repeat. */
5904 }
5907 }
5909 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
5910 must be a reference-to-function or a pointer-to-function type, as specified
5911 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
5912 and check that the resulting function has external linkage. */
5914 static tree
5916 tsubst_flags_t complain)
5917 {
5920 linkage_kind linkage;
5932 /* [temp.arg.nontype]/1
5934 A template-argument for a non-type, non-template template-parameter
5935 shall be one of:
5936 [...]
5937 -- the address of an object or function with external [C++11: or
5938 internal] linkage. */
5941 {
5943 {
5949 else
5952 }
5954 }
5958 {
5960 {
5965 else
5969 }
5971 }
5979 }
5981 /* Subroutine of convert_nontype_argument.
5982 Check if EXPR of type TYPE is a valid pointer-to-member constant.
5983 Emit an error otherwise. */
5985 static bool
5987 tsubst_flags_t complain)
5988 {
5999 {
6003 }
6005 }
6007 /* Returns TRUE iff the address of OP is value-dependent.
6009 14.6.2.4 [temp.dep.temp]:
6010 A non-integral non-type template-argument is dependent if its type is
6011 dependent or it has either of the following forms
6012 qualified-id
6013 & qualified-id
6014 and contains a nested-name-specifier which specifies a class-name that
6015 names a dependent type.
6017 We generalize this to just say that the address of a member of a
6018 dependent class is value-dependent; the above doesn't cover the
6019 address of a static data member named with an unqualified-id. */
6021 static bool
6023 {
6024 /* We could use get_inner_reference here, but there's no need;
6025 this is only relevant for template non-type arguments, which
6026 can only be expressed as &id-expression. */
6028 {
6032 }
6035 }
6037 /* The next set of functions are used for providing helpful explanatory
6038 diagnostics for failed overload resolution. Their messages should be
6039 indented by two spaces for consistency with the messages in
6040 call.c */
6042 static int
6044 {
6046 }
6048 static int
6050 {
6055 }
6057 static int
6059 {
6061 }
6063 static int
6065 {
6071 }
6073 static int
6075 {
6079 }
6081 static int
6083 {
6086 " template parameter %qD is not a parameter pack, but "
6090 }
6092 static int
6094 {
6097 " template argument %qE does not match "
6101 }
6103 static int
6105 {
6109 }
6111 static int
6113 {
6119 }
6121 static int
6123 {
6125 {
6130 else
6132 " deduced conflicting values for non-type parameter "
6134 }
6136 }
6138 static int
6140 {
6143 " variable-sized array type %qT is not "
6145 arg);
6147 }
6149 static int
6151 {
6155 arg);
6157 }
6159 static int
6161 {
6163 {
6169 else
6174 }
6176 }
6178 static int
6180 {
6182 }
6184 static int
6187 {
6189 }
6191 static int
6194 {
6200 }
6202 static int
6205 {
6208 {
6216 }
6218 }
6220 static int
6222 {
6225 " template parameters of a template template argument are "
6228 }
6230 static int
6232 {
6238 }
6240 static int
6242 {
6247 }
6249 static int
6251 {
6255 arg);
6257 }
6259 /* Attempt to convert the non-type template parameter EXPR to the
6260 indicated TYPE. If the conversion is successful, return the
6261 converted value. If the conversion is unsuccessful, return
6262 NULL_TREE if we issued an error message, or error_mark_node if we
6263 did not. We issue error messages for out-and-out bad template
6264 parameters, but not simply because the conversion failed, since we
6265 might be just trying to do argument deduction. Both TYPE and EXPR
6266 must be non-dependent.
6268 The conversion follows the special rules described in
6269 [temp.arg.nontype], and it is much more strict than an implicit
6270 conversion.
6272 This function is called twice for each template argument (see
6273 lookup_template_class for a more accurate description of this
6274 problem). This means that we need to handle expressions which
6275 are not valid in a C++ source, but can be created from the
6276 first call (for instance, casts to perform conversions). These
6277 hacks can go away after we fix the double coercion problem. */
6279 static tree
6281 {
6282 tree expr_type;
6284 /* Detect immediately string literals as invalid non-type argument.
6285 This special-case is not needed for correctness (we would easily
6286 catch this later), but only to provide better diagnostic for this
6287 common user mistake. As suggested by DR 100, we do not mention
6288 linkage issues in the diagnostic as this is not the point. */
6289 /* FIXME we're making this OK. */
6291 {
6297 }
6299 /* Add the ADDR_EXPR now for the benefit of
6300 value_dependent_expression_p. */
6303 {
6307 }
6309 /* If we are in a template, EXPR may be non-dependent, but still
6310 have a syntactic, rather than semantic, form. For example, EXPR
6311 might be a SCOPE_REF, rather than the VAR_DECL to which the
6312 SCOPE_REF refers. Preserving the qualifying scope is necessary
6313 so that access checking can be performed when the template is
6314 instantiated -- but here we need the resolved form so that we can
6315 convert the argument. */
6328 else
6331 /* If the argument is non-dependent, perform any conversions in
6332 non-dependent context as well. */
6340 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6341 to a non-type argument of "nullptr". */
6345 /* In C++11, integral or enumeration non-type template arguments can be
6346 arbitrary constant expressions. Pointer and pointer to
6347 member arguments can be general constant expressions that evaluate
6348 to a null value, but otherwise still need to be of a specific form. */
6350 {
6352 /* A PTRMEM_CST is already constant, and a valid template
6353 argument for a parameter of pointer to member type, we just want
6354 to leave it in that form rather than lower it to a
6359 {
6363 {
6367 }
6368 }
6370 {
6375 }
6376 }
6378 /* HACK: Due to double coercion, we can get a
6379 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6380 which is the tree that we built on the first call (see
6381 below when coercing to reference to object or to reference to
6382 function). We just strip everything and get to the arg.
6383 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6384 for examples. */
6386 {
6392 {
6393 /* ??? Maybe we could use convert_from_reference here, but we
6394 would need to relax its constraints because the NOP_EXPR
6395 could actually change the type to something more cv-qualified,
6396 and this is not folded by convert_from_reference. */
6401 && (same_type_ignoring_top_level_qualifiers_p
6404 {
6407 }
6408 }
6409 }
6411 /* We could also generate a NOP_EXPR(ADDR_EXPR()) when the
6412 parameter is a pointer to object, through decay and
6413 qualification conversion. Let's strip everything. */
6415 {
6420 {
6421 /* Skip the ADDR_EXPR only if it is part of the decay for
6422 an array. Otherwise, it is part of the original argument
6423 in the source code. */
6428 }
6429 }
6431 /* [temp.arg.nontype]/5, bullet 1
6433 For a non-type template-parameter of integral or enumeration type,
6434 integral promotions (_conv.prom_) and integral conversions
6435 (_conv.integral_) are applied. */
6437 {
6446 /* Notice that there are constant expressions like '4 % 0' which
6447 do not fold into integer constants. */
6450 {
6452 {
6463 /* else cxx_constant_value complained but gave us
6464 a real constant, so go ahead. */
6466 }
6467 else
6469 }
6471 /* Avoid typedef problems. */
6474 }
6475 /* [temp.arg.nontype]/5, bullet 2
6477 For a non-type template-parameter of type pointer to object,
6478 qualification conversions (_conv.qual_) and the array-to-pointer
6479 conversion (_conv.array_) are applied. */
6481 {
6482 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6484 A template-argument for a non-type, non-template template-parameter
6485 shall be one of: [...]
6487 -- the name of a non-type template-parameter;
6488 -- the address of an object or function with external linkage, [...]
6489 expressed as "& id-expression" where the & is optional if the name
6490 refers to a function or array, or if the corresponding
6491 template-parameter is a reference.
6493 Here, we do not care about functions, as they are invalid anyway
6494 for a parameter of type pointer-to-object. */
6497 /* Non-type template parameters are OK. */
6498 ;
6503 {
6505 {
6508 "because %qD is a variable, not the address of "
6511 }
6513 {
6519 }
6520 /* Other values, like integer constants, might be valid
6521 non-type arguments of some other type. */
6523 }
6524 else
6525 {
6526 tree decl;
6531 {
6536 }
6538 {
6544 }
6546 {
6551 }
6552 }
6561 }
6562 /* [temp.arg.nontype]/5, bullet 3
6564 For a non-type template-parameter of type reference to object, no
6565 conversions apply. The type referred to by the reference may be more
6566 cv-qualified than the (otherwise identical) type of the
6567 template-argument. The template-parameter is bound directly to the
6568 template-argument, which must be an lvalue. */
6570 {
6572 expr_type))
6576 {
6581 }
6584 {
6589 }
6591 /* [temp.arg.nontype]/1
6593 A template-argument for a non-type, non-template template-parameter
6594 shall be one of: [...]
6596 -- the address of an object or function with external linkage. */
6599 {
6602 {
6605 "because a reference variable does not have a constant "
6608 }
6609 }
6612 {
6614 {
6620 }
6622 /* DR 1155 allows internal linkage in C++11 and up. */
6625 {
6631 }
6634 }
6635 }
6636 /* [temp.arg.nontype]/5, bullet 4
6638 For a non-type template-parameter of type pointer to function, only
6639 the function-to-pointer conversion (_conv.func_) is applied. If the
6640 template-argument represents a set of overloaded functions (or a
6641 pointer to such), the matching function is selected from the set
6642 (_over.over_). */
6644 {
6645 /* If the argument is a template-id, we might not have enough
6646 context information to decay the pointer. */
6648 {
6652 }
6655 /* Null pointer values are OK in C++11. */
6662 }
6663 /* [temp.arg.nontype]/5, bullet 5
6665 For a non-type template-parameter of type reference to function, no
6666 conversions apply. If the template-argument represents a set of
6667 overloaded functions, the matching function is selected from the set
6668 (_over.over_). */
6670 {
6672 {
6674 {
6679 }
6681 }
6687 }
6688 /* [temp.arg.nontype]/5, bullet 6
6690 For a non-type template-parameter of type pointer to member function,
6691 no conversions apply. If the template-argument represents a set of
6692 overloaded member functions, the matching member function is selected
6693 from the set (_over.over_). */
6695 {
6700 /* [temp.arg.nontype] bullet 1 says the pointer to member
6701 expression must be a pointer-to-member constant. */
6706 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
6707 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
6711 /* There is no way to disable standard conversions in
6712 resolve_address_of_overloaded_function (called by
6713 instantiate_type). It is possible that the call succeeded by
6714 converting &B::I to &D::I (where B is a base of D), so we need
6715 to reject this conversion here.
6717 Actually, even if there was a way to disable standard conversions,
6718 it would still be better to reject them here so that we can
6719 provide a superior diagnostic. */
6721 {
6723 {
6727 /* If we are just one standard conversion off, explain. */
6731 }
6733 }
6734 }
6735 /* [temp.arg.nontype]/5, bullet 7
6737 For a non-type template-parameter of type pointer to data member,
6738 qualification conversions (_conv.qual_) are applied. */
6740 {
6741 /* [temp.arg.nontype] bullet 1 says the pointer to member
6742 expression must be a pointer-to-member constant. */
6750 }
6752 {
6754 {
6759 }
6761 }
6762 /* A template non-type parameter must be one of the above. */
6763 else
6766 /* Sanity check: did we actually convert the argument to the
6767 right type? */
6771 }
6773 /* Subroutine of coerce_template_template_parms, which returns 1 if
6774 PARM_PARM and ARG_PARM match using the rule for the template
6775 parameters of template template parameters. Both PARM and ARG are
6776 template parameters; the rest of the arguments are the same as for
6777 coerce_template_template_parms.
6778 */
6779 static int
6781 tree arg,
6782 tsubst_flags_t complain,
6783 tree in_decl,
6784 tree outer_args)
6785 {
6794 {
6796 /* We encounter instantiations of templates like
6797 template <template <template <class> class> class TT>
6798 class C; */
6799 {
6806 }
6807 /* Fall through. */
6812 /* Argument is a parameter pack but parameter is not. */
6817 /* The tsubst call is used to handle cases such as
6819 template <int> class C {};
6820 template <class T, template <T> class TT> class D {};
6821 D<int, C> d;
6823 i.e. the parameter list of TT depends on earlier parameters. */
6825 {
6830 }
6834 /* Argument is a parameter pack but parameter is not. */
6841 }
6844 }
6847 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
6848 template template parameters. Both PARM_PARMS and ARG_PARMS are
6849 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
6850 or PARM_DECL.
6852 Consider the example:
6853 template <class T> class A;
6854 template<template <class U> class TT> class B;
6856 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
6857 the parameters to A, and OUTER_ARGS contains A. */
6859 static int
6861 tree arg_parms,
6862 tsubst_flags_t complain,
6863 tree in_decl,
6864 tree outer_args)
6865 {
6876 /* Determine whether we have a parameter pack at the end of the
6877 template template parameter's template parameter list. */
6879 {
6886 {
6900 }
6901 }
6907 /* Check all of the template parameters except the parameter pack at
6908 the end (if any). */
6910 {
6919 outer_args))
6922 }
6925 {
6926 /* Check each of the template parameters in the template
6927 argument against the template parameter pack at the end of
6928 the template template parameter. */
6935 {
6942 outer_args))
6944 }
6945 }
6948 }
6950 /* Verifies that the deduced template arguments (in TARGS) for the
6951 template template parameters (in TPARMS) represent valid bindings,
6952 by comparing the template parameter list of each template argument
6953 to the template parameter list of its corresponding template
6954 template parameter, in accordance with DR150. This
6955 routine can only be called after all template arguments have been
6956 deduced. It will return TRUE if all of the template template
6957 parameter bindings are okay, FALSE otherwise. */
6958 bool
6960 {
6964 /* We're dealing with template parms in this process. */
6970 {
6975 {
6980 {
6981 /* Look inside the argument pack. */
6984 }
6987 {
6991 /* Extract the next argument from the argument
6992 pack. */
6996 /* Look at the pattern of the pack expansion. */
6999 /* Extract the template parameters from the template
7000 argument. */
7006 /* Verify that we can coerce the template template
7007 parameters from the template argument to the template
7008 parameter. This requires an exact match. */
7010 && !coerce_template_template_parms
7012 targ_parms,
7013 tf_none,
7014 tparm,
7015 targs))
7016 {
7019 }
7020 }
7021 }
7022 }
7024 out:
7028 }
7030 /* Since type attributes aren't mangled, we need to strip them from
7031 template type arguments. */
7033 static tree
7035 {
7045 }
7047 /* And from inside dependent non-type arguments like sizeof(Type). */
7049 static tree
7051 {
7061 }
7063 // A template declaration can be substituted for a constrained
7064 // template template parameter only when the argument is more
7065 // constrained than the parameter.
7066 static bool
7068 {
7071 /* For now, allow constrained template template arguments
7072 and unconstrained template template parameters. */
7078 // If the template parameter is constrained, we need to rewrite its
7079 // constraints in terms of the ARG's template parameters. This ensures
7080 // that all of the template parameter types will have the same depth.
7081 //
7082 // Note that this is only valid when coerce_template_template_parm is
7083 // true for the innermost template parameters of PARM and ARG. In other
7084 // words, because coercion is successful, this conversion will be valid.
7086 {
7093 }
7096 }
7098 // Convert a placeholder argument into a binding to the original
7099 // parameter. The original parameter is saved as the TREE_TYPE of
7100 // ARG.
7103 {
7106 }
7108 /* Convert the indicated template ARG as necessary to match the
7109 indicated template PARM. Returns the converted ARG, or
7110 error_mark_node if the conversion was unsuccessful. Error and
7111 warning messages are issued under control of COMPLAIN. This
7112 conversion is for the Ith parameter in the parameter list. ARGS is
7113 the full set of template arguments deduced so far. */
7115 static tree
7117 tree arg,
7118 tree args,
7119 tsubst_flags_t complain,
7121 tree in_decl)
7122 {
7123 tree orig_arg;
7124 tree val;
7130 /* Trivially convert placeholders. */
7136 {
7137 /* The template argument was the name of some
7138 member function. That's usually
7139 invalid, but static members are OK. In any
7140 case, grab the underlying fields/functions
7141 and issue an error later if required. */
7144 }
7152 /* When determining whether an argument pack expansion is a template,
7153 look at the pattern. */
7157 /* Deal with an injected-class-name used as a template template arg. */
7159 {
7162 {
7172 }
7173 }
7175 is_tmpl_type =
7191 {
7193 {
7197 }
7200 "to refer to a type member of a template parameter, "
7205 typename_type,
7206 complain);
7209 }
7211 {
7213 {
7215 {
7227 else
7230 }
7231 }
7233 }
7235 {
7237 {
7244 else
7247 }
7249 }
7252 {
7254 {
7258 /* The number of argument required is not known yet.
7259 Just accept it for now. */
7261 else
7262 {
7264 tree argparm;
7266 /* Strip alias templates that are equivalent to another
7267 template. */
7273 args))
7274 {
7277 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7278 TEMPLATE_DECL. */
7280 {
7285 }
7286 }
7287 else
7288 {
7290 {
7297 }
7300 }
7302 // Check that the constraints are compatible before allowing the
7303 // substitution.
7306 {
7308 {
7314 }
7316 }
7317 }
7318 }
7319 else
7321 /* We only form one instance of each template specialization.
7322 Therefore, if we use a non-canonical variant (i.e., a
7323 typedef), any future messages referring to the type will use
7324 the typedef, which is confusing if those future uses do not
7325 themselves also use the typedef. */
7328 }
7329 else
7330 {
7334 {
7338 }
7344 {
7347 else
7348 {
7349 /* Not sure if this is reachable, but it doesn't hurt
7350 to be robust. */
7353 }
7354 }
7357 /* We used to call digest_init here. However, digest_init
7358 will report errors, which we don't want when complain
7359 is zero. More importantly, digest_init will try too
7360 hard to convert things: for example, `0' should not be
7361 converted to pointer type at this point according to
7362 the standard. Accepting this is not merely an
7363 extension, since deciding whether or not these
7364 conversions can occur is part of determining which
7365 function template to call, or whether a given explicit
7366 argument specification is valid. */
7368 else
7378 {
7379 /* Reject template arguments that are references to built-in
7380 functions with no library fallbacks. */
7388 }
7391 {
7392 /* Strip typedefs from the SCOPE_REF. */
7395 complain);
7398 }
7399 }
7402 }
7404 /* Coerces the remaining template arguments in INNER_ARGS (from
7405 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
7406 Returns the coerced argument pack. PARM_IDX is the position of this
7407 parameter in the template parameter list. ARGS is the original
7408 template argument list. */
7409 static tree
7412 tree args,
7413 tree inner_args,
7415 tree new_args,
7417 tree in_decl,
7418 tsubst_flags_t complain)
7419 {
7422 tree packed_args;
7423 tree argument_pack;
7430 {
7431 /* When the template parameter is a non-type template parameter pack
7432 or template template parameter pack whose type or template
7433 parameters use parameter packs, we know exactly how many arguments
7434 we are looking for. Build a vector of the instantiated decls for
7435 these template parameters in PACKED_PARMS. */
7436 /* We can't use make_pack_expansion here because it would interpret a
7437 _DECL as a use rather than a declaration. */
7451 /* If we're doing a partial instantiation of a member template,
7452 verify that all of the types used for the non-type
7453 template parameter pack are, in fact, valid for non-type
7454 template parameters. */
7457 {
7460 {
7464 }
7465 /* We don't know how many args we have yet, just
7466 use the unconverted ones for now. */
7468 }
7471 }
7472 /* Check if we have a placeholder pack, which indicates we're
7473 in the context of a introduction list. In that case we want
7474 to match this pack to the single placeholder. */
7478 {
7481 }
7482 else
7485 /* Convert the remaining arguments, which will be a part of the
7486 parameter pack "parm". */
7489 {
7495 {
7496 /* Once we've packed as many args as we have types, stop. */
7500 /* We don't know how many args we have yet, just
7501 use the unconverted ones for now. */
7503 else
7505 }
7508 {
7511 }
7512 else
7515 in_decl);
7519 }
7523 {
7528 }
7533 else
7534 {
7539 }
7546 }
7548 /* Returns the number of pack expansions in the template argument vector
7549 ARGS. */
7551 static int
7553 {
7558 {
7562 }
7564 }
7566 /* Convert all template arguments to their appropriate types, and
7567 return a vector containing the innermost resulting template
7568 arguments. If any error occurs, return error_mark_node. Error and
7569 warning messages are issued under control of COMPLAIN.
7571 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
7572 for arguments not specified in ARGS. Otherwise, if
7573 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
7574 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
7575 USE_DEFAULT_ARGS is false, then all arguments must be specified in
7576 ARGS. */
7578 static tree
7580 tree args,
7581 tree in_decl,
7582 tsubst_flags_t complain,
7585 {
7587 tree orig_inner_args;
7588 tree inner_args;
7589 tree new_args;
7590 tree new_inner_args;
7594 /* When used as a boolean value, indicates whether this is a
7595 variadic template parameter list. Since it's an int, we can also
7596 subtract it from nparms to get the number of non-variadic
7597 parameters. */
7602 /* Likewise for parameters with default arguments. */
7610 /* Determine if there are any parameter packs or default arguments. */
7612 {
7620 }
7623 /* If there are no parameters that follow a parameter pack, we need to
7624 expand any argument packs so that we can deduce a parameter pack from
7625 some non-packed args followed by an argument pack, as in variadic85.C.
7626 If there are such parameters, we need to leave argument packs intact
7627 so the arguments are assigned properly. This can happen when dealing
7628 with a nested class inside a partial specialization of a class
7629 template, as in variadic92.C, or when deducing a template parameter pack
7630 from a sub-declarator, as in variadic114.C. */
7634 /* Count any pack expansion args. */
7640 && require_all_args
7641 && !variadic_args_p
7642 && (!use_default_args
7645 {
7647 {
7649 {
7653 }
7654 else
7661 }
7664 }
7665 /* We can't pass a pack expansion to a non-pack parameter of an alias
7666 template (DR 1430). */
7670 && variadic_args_p
7672 {
7674 {
7676 {
7682 {
7685 "pack expansion argument for non-pack parameter "
7687 else
7689 "pack expansion argument for non-pack parameter "
7693 }
7694 }
7696 found:;
7697 }
7699 }
7701 /* We need to evaluate the template arguments, even though this
7702 template-id may be nested within a "sizeof". */
7711 {
7712 tree arg;
7713 tree parm;
7715 /* Get the Ith template parameter. */
7719 {
7722 }
7724 /* Calculate the next argument. */
7727 else
7732 {
7733 /* Some arguments will be placed in the
7734 template parameter pack PARM. */
7741 {
7742 /* We don't know how many args we have yet, just use the
7743 unconverted (and still packed) ones for now. */
7747 }
7751 /* Store this argument. */
7753 {
7754 lost++;
7755 /* We are done with all of the arguments. */
7757 }
7758 else
7759 {
7762 }
7765 }
7767 {
7769 {
7770 /* "If every valid specialization of a variadic template
7771 requires an empty template parameter pack, the template is
7772 ill-formed, no diagnostic required." So check that the
7773 pattern works with this parameter. */
7778 in_decl);
7780 {
7784 }
7786 /* Recover from missing typename. */
7790 /* We don't know how many args we have yet, just
7791 use the unconverted ones for now. */
7795 }
7796 }
7798 {
7799 /* There must be a default arg in this case. */
7802 /* The position of the first default template argument,
7803 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
7804 Record that. */
7808 }
7809 else
7813 {
7816 }
7818 /* This only occurs if there was an error in the template
7819 parameter list itself (which we would already have
7820 reported) that we are trying to recover from, e.g., a class
7821 template with a parameter list such as
7822 template<typename..., typename>. */
7824 else
7830 lost++;
7832 }
7837 {
7839 {
7844 }
7846 }
7856 }
7858 /* Convert all template arguments to their appropriate types, and
7859 return a vector containing the innermost resulting template
7860 arguments. If any error occurs, return error_mark_node. Error and
7861 warning messages are not issued.
7863 Note that no function argument deduction is performed, and default
7864 arguments are used to fill in unspecified arguments. */
7865 tree
7867 {
7869 }
7871 /* Convert all template arguments to their appropriate type, and
7872 instantiate default arguments as needed. This returns a vector
7873 containing the innermost resulting template arguments, or
7874 error_mark_node if unsuccessful. */
7875 tree
7877 tsubst_flags_t complain)
7878 {
7880 }
7882 /* Like coerce_template_parms. If PARMS represents all template
7883 parameters levels, this function returns a vector of vectors
7884 representing all the resulting argument levels. Note that in this
7885 case, only the innermost arguments are coerced because the
7886 outermost ones are supposed to have been coerced already.
7888 Otherwise, if PARMS represents only (the innermost) vector of
7889 parameters, this function returns a vector containing just the
7890 innermost resulting arguments. */
7892 static tree
7894 tree args,
7895 tree in_decl,
7896 tsubst_flags_t complain,
7899 {
7902 tree coerced_args;
7905 {
7907 tree level;
7913 {
7914 tree l;
7918 require_all_args,
7919 use_default_args);
7920 else
7927 }
7928 }
7929 else
7932 require_all_args,
7933 use_default_args);
7935 }
7937 /* Returns 1 if template args OT and NT are equivalent. */
7939 int
7941 {
7948 /* For member templates */
7957 {
7974 }
7978 {
7981 /* Don't treat an alias template specialization with dependent
7982 arguments as equivalent to its underlying type when used as a
7983 template argument; we need them to be distinct so that we
7984 substitute into the specialization arguments at instantiation
7985 time. And aliases can't be equivalent without being ==, so
7986 we don't need to look any deeper. */
7989 else
7991 }
7994 else
7995 {
7996 /* Try to treat a template non-type argument that has been converted
7997 to the parameter type as equivalent to one that hasn't yet. */
8010 }
8011 }
8013 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8014 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8015 NEWARG_PTR with the offending arguments if they are non-NULL. */
8017 int
8020 {
8033 {
8038 {
8044 }
8045 }
8047 }
8049 static void
8051 {
8061 /* We are called both from instantiate_decl, where we've already had a
8062 tinst_level pushed, and instantiate_template, where we haven't.
8063 Compensate. */
8074 else
8083 }
8086 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
8087 ARGLIST. Valid choices for FNS are given in the cp-tree.def
8088 documentation for TEMPLATE_ID_EXPR. */
8090 tree
8092 {
8093 tree type;
8101 {
8104 }
8107 {
8109 unknown_type_node,
8111 arglist);
8113 }
8120 }
8122 /* Within the scope of a template class S<T>, the name S gets bound
8123 (in build_self_reference) to a TYPE_DECL for the class, not a
8124 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
8125 or one of its enclosing classes, and that type is a template,
8126 return the associated TEMPLATE_DECL. Otherwise, the original
8127 DECL is returned.
8129 Also handle the case when DECL is a TREE_LIST of ambiguous
8130 injected-class-names from different bases. */
8132 tree
8134 {
8138 /* DR 176: A lookup that finds an injected-class-name (10.2
8139 [class.member.lookup]) can result in an ambiguity in certain cases
8140 (for example, if it is found in more than one base class). If all of
8141 the injected-class-names that are found refer to specializations of
8142 the same class template, and if the name is followed by a
8143 template-argument-list, the reference refers to the class template
8144 itself and not a specialization thereof, and is not ambiguous. */
8146 {
8149 {
8155 }
8158 else
8160 }
8166 }
8168 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
8169 parameters, find the desired type.
8171 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
8173 IN_DECL, if non-NULL, is the template declaration we are trying to
8174 instantiate.
8176 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
8177 the class we are looking up.
8179 Issue error and warning messages under control of COMPLAIN.
8181 If the template class is really a local class in a template
8182 function, then the FUNCTION_CONTEXT is the function in which it is
8183 being instantiated.
8185 ??? Note that this function is currently called *twice* for each
8186 template-id: the first time from the parser, while creating the
8187 incomplete type (finish_template_type), and the second type during the
8188 real instantiation (instantiate_template_class). This is surely something
8189 that we want to avoid. It also causes some problems with argument
8190 coercion (see convert_nontype_argument for more information on this). */
8192 static tree
8195 {
8197 tree t;
8200 spec_entry elt;
8201 hashval_t hash;
8204 {
8208 else
8209 {
8216 }
8219 }
8221 {
8224 /* If we are declaring a constructor, say A<T>::A<T>, we will get
8225 an implicit typename for the second A. Deal with it. */
8230 {
8233 }
8234 }
8237 {
8240 }
8242 {
8246 }
8248 {
8251 }
8253 /* Issue an error message if we didn't find a template. */
8255 {
8259 }
8262 /* Make sure it's a user visible template, if it was named by
8263 the user. */
8266 {
8268 {
8272 }
8274 }
8278 /* An alias that just changes the name of a template is equivalent to the
8279 other template, so if any of the arguments are pack expansions, strip
8280 the alias to avoid problems with a pack expansion passed to a non-pack
8281 alias template parameter (DR 1430). */
8286 {
8287 /* Create a new TEMPLATE_DECL and TEMPLATE_TEMPLATE_PARM node to store
8288 template arguments */
8290 tree parm;
8291 tree arglist2;
8292 tree outer;
8296 /* Consider an example where a template template parameter declared as
8298 template <class T, class U = std::allocator<T> > class TT
8300 The template parameter level of T and U are one level larger than
8301 of TT. To proper process the default argument of U, say when an
8302 instantiation `TT<int>' is seen, we need to build the full
8303 arguments containing {int} as the innermost level. Outer levels,
8304 available when not appearing as default template argument, can be
8305 obtained from the arguments of the enclosing template.
8307 Suppose that TT is later substituted with std::vector. The above
8308 instantiation is `TT<int, std::allocator<T> >' with TT at
8309 level 1, and T at level 2, while the template arguments at level 1
8310 becomes {std::vector} and the inner level 2 is {int}. */
8316 {
8317 /* This is an argument of the current template, so we haven't set
8318 DECL_CONTEXT yet. */
8319 tree relevant_template_parms;
8321 /* Parameter levels that are greater than the level of the given
8322 template template parm are irrelevant. */
8329 }
8335 complain,
8345 }
8346 else
8347 {
8349 tree gen_tmpl;
8350 tree type_decl;
8358 /* An error occurred while building the template TEMPL, and a
8359 diagnostic has most certainly been emitted for that
8360 already. Let's propagate that error. */
8369 {
8370 /* We've been given an incomplete set of template arguments.
8371 For example, given:
8373 template <class T> struct S1 {
8374 template <class U> struct S2 {};
8375 template <class U> struct S2<U*> {};
8376 };
8378 we will be called with an ARGLIST of `U*', but the
8379 TEMPLATE will be `template <class T> template
8380 <class U> struct S1<T>::S2'. We must fill in the missing
8381 arguments. */
8385 }
8387 /* Now we should have enough arguments. */
8390 /* From here on, we're only interested in the most general
8391 template. */
8393 /* Calculate the BOUND_ARGS. These will be the args that are
8394 actually tsubst'd into the definition to create the
8395 instantiation. */
8397 complain,
8402 /* We were unable to bind the arguments. */
8405 /* In the scope of a template class, explicit references to the
8406 template class refer to the type of the template, not any
8407 instantiation of it. For example, in:
8409 template <class T> class C { void f(C<T>); }
8411 the `C<T>' is just the same as `C'. Outside of the
8412 class, however, such a reference is an instantiation. */
8416 {
8421 }
8423 /* If we already have this specialization, return it. */
8433 /* If the the template's constraints are not satisfied,
8434 then we cannot form a valid type.
8436 Note that the check is deferred until after the hash
8437 lookup. This prevents redundant checks on previously
8438 instantiated specializations. */
8440 {
8442 {
8445 }
8447 }
8451 /* If the deduced arguments are invalid, then the binding
8452 failed. */
8456 complain))
8463 {
8468 }
8478 /* Create the type. */
8480 {
8481 /* The user referred to a specialization of an alias
8482 template represented by GEN_TMPL.
8484 [temp.alias]/2 says:
8486 When a template-id refers to the specialization of an
8487 alias template, it is equivalent to the associated
8488 type obtained by substitution of its
8489 template-arguments for the template-parameters in the
8490 type-id of the alias template. */
8493 /* Note that the call above (by indirectly calling
8494 register_specialization in tsubst_decl) registers the
8495 TYPE_DECL representing the specialization of the alias
8496 template. So next time someone substitutes ARGLIST for
8497 the template parms into the alias template (GEN_TMPL),
8498 she'll get that TYPE_DECL back. */
8502 }
8504 {
8506 {
8517 }
8518 else
8519 {
8520 /* We don't want to call start_enum for this type, since
8521 the values for the enumeration constants may involve
8522 template parameters. And, no one should be interested
8523 in the enumeration constants for such a type. */
8526 }
8530 }
8532 {
8538 /* A local class. Make sure the decl gets registered properly. */
8543 /* This instantiation is another name for the primary
8544 template type. Set the TYPE_CANONICAL field
8545 appropriately. */
8548 /* Some of the template arguments require structural
8549 equality testing, so this template class requires
8550 structural equality testing. */
8552 }
8553 else
8556 /* If we called start_enum or pushtag above, this information
8557 will already be set up. */
8559 {
8566 }
8567 else
8571 {
8577 {
8580 }
8581 }
8585 {
8589 {
8590 tree attributes
8598 }
8599 }
8601 /* Let's consider the explicit specialization of a member
8602 of a class template specialization that is implicitly instantiated,
8603 e.g.:
8604 template<class T>
8605 struct S
8606 {
8607 template<class U> struct M {}; //#0
8608 };
8610 template<>
8611 template<>
8612 struct S<int>::M<char> //#1
8613 {
8614 int i;
8615 };
8616 [temp.expl.spec]/4 says this is valid.
8618 In this case, when we write:
8619 S<int>::M<char> m;
8621 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
8622 the one of #0.
8624 When we encounter #1, we want to store the partial instantiation
8625 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
8627 For all cases other than this "explicit specialization of member of a
8628 class template", we just want to store the most general template into
8629 the CLASSTYPE_TI_TEMPLATE of M.
8631 This case of "explicit specialization of member of a class template"
8632 only happens when:
8633 1/ the enclosing class is an instantiation of, and therefore not
8634 the same as, the context of the most general template, and
8635 2/ we aren't looking at the partial instantiation itself, i.e.
8636 the innermost arguments are not the same as the innermost parms of
8637 the most general template.
8639 So it's only when 1/ and 2/ happens that we want to use the partial
8640 instantiation of the member template in lieu of its most general
8641 template. */
8645 /* the enclosing class must be an instantiation... */
8648 {
8652 tree partial_inst_args =
8659 use_partial_inst_tmpl =
8660 /*...and we must not be looking at the partial instantiation
8661 itself. */
8663 partial_inst_args);
8664 }
8667 /* This case is easy; there are no member templates involved. */
8669 else
8670 {
8671 /* This is a full instantiation of a member template. Find
8672 the partial instantiation of which this is an instance. */
8674 /* Temporarily reduce by one the number of levels in the ARGLIST
8675 so as to avoid comparing the last set of arguments. */
8679 /* FOUND is either a proper class type, or an alias
8680 template specialization. In the later case, it's a
8681 TYPE_DECL, resulting from the substituting of arguments
8682 for parameters in the TYPE_DECL of the alias template
8683 done earlier. So be careful while getting the template
8684 of FOUND. */
8686 ? found
8690 }
8692 // Build template info for the new specialization.
8701 /* Note this use of the partial instantiation so we can check it
8702 later in maybe_process_partial_specialization. */
8709 /* Now that the type has been registered on the instantiations
8710 list, we set up the enumerators. Because the enumeration
8711 constants may involve the enumeration type itself, we make
8712 sure to register the type first, and then create the
8713 constants. That way, doing tsubst_expr for the enumeration
8714 constants won't result in recursive calls here; we'll find
8715 the instantiation and exit above. */
8719 /* If the type makes use of template parameters, the
8720 code that generates debugging information will crash. */
8723 /* Possibly limit visibility based on template args. */
8730 }
8731 }
8733 /* Wrapper for lookup_template_class_1. */
8735 tree
8738 {
8739 tree ret;
8745 }
8747 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
8749 tree
8751 {
8752 /* The type of the expression is NULL_TREE since the template-id could refer
8753 to an explicit or partial specialization. */
8756 /* Except that concepts are always bool. */
8759 }
8761 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
8763 tree
8765 {
8769 /* We never want to return a VAR_DECL for a variable concept, since they
8770 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
8784 {
8786 {
8789 }
8791 }
8793 /* If a template-id refers to a specialization of a variable
8794 concept, then the expression is true if and only if the
8795 concept's constraints are satisfied by the given template
8796 arguments.
8798 NOTE: This is an extension of Concepts Lite TS that
8799 allows constraints to be used in expressions. */
8801 {
8804 }
8807 }
8809 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
8810 TARGS template args, and instantiate it if it's not dependent. */
8812 static tree
8814 tsubst_flags_t complain)
8815 {
8818 {
8821 }
8824 }
8826 \f
8827 struct pair_fn_data
8828 {
8829 tree_fn_t fn;
8830 tree_fn_t any_fn;
8832 /* True when we should also visit template parameters that occur in
8833 non-deduced contexts. */
8836 };
8838 /* Called from for_each_template_parm via walk_tree. */
8840 static tree
8842 {
8849 #define WALK_SUBTREE(NODE) \
8850 do \
8851 { \
8852 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
8853 pfd->include_nondeduced_p, \
8854 pfd->any_fn); \
8855 if (result) goto out; \
8856 } \
8857 while (0)
8867 {
8871 /* Fall through. */
8877 else
8887 /* Since we're not going to walk subtrees, we have to do this
8888 explicitly here. */
8890 /* Fall through. */
8893 /* Check the return type. */
8896 /* Check the parameter types. Since default arguments are not
8897 instantiated until they are needed, the TYPE_ARG_TYPES may
8898 contain expressions that involve template parameters. But,
8899 no-one should be looking at them yet. And, once they're
8900 instantiated, they don't contain template parameters, so
8901 there's no point in looking at them then, either. */
8902 {
8903 tree parm;
8908 /* Since we've already handled the TYPE_ARG_TYPES, we don't
8909 want walk_tree walking into them itself. */
8911 }
8914 {
8918 }
8935 /* Fall through. */
8947 /* Record template parameters such as `T' inside `TT<T>'. */
8949 /* Fall through. */
8959 /* In C++17 we can deduce a type argument from the type of a non-type
8960 argument. */
8967 /* A template template parameter is encountered. */
8971 /* Already substituted template template parameter */
8976 /* A template-id in a TYPENAME_TYPE might be a deduced context after
8977 partial instantiation. */
8989 /* If there's no type, then this thing must be some expression
8990 involving template parameters. */
9012 }
9014 #undef WALK_SUBTREE
9016 /* We didn't find any template parameters we liked. */
9017 out:
9019 }
9021 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9022 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9023 call FN with the parameter and the DATA.
9024 If FN returns nonzero, the iteration is terminated, and
9025 for_each_template_parm returns 1. Otherwise, the iteration
9026 continues. If FN never returns a nonzero value, the value
9027 returned by for_each_template_parm is 0. If FN is NULL, it is
9028 considered to be the function which always returns 1.
9030 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9031 parameters that occur in non-deduced contexts. When false, only
9032 visits those template parameters that can be deduced. */
9034 static tree
9038 tree_fn_t any_fn)
9039 {
9041 tree result;
9043 /* Set up. */
9049 /* Walk the tree. (Conceptually, we would like to walk without
9050 duplicates, but for_each_template_parm_r recursively calls
9051 for_each_template_parm, so we would need to reorganize a fair
9052 bit to use walk_tree_without_duplicates, so we keep our own
9053 visited list.) */
9056 else
9059 for_each_template_parm_r,
9063 /* Clean up. */
9065 {
9068 }
9071 }
9073 /* Returns true if T depends on any template parameter. */
9075 int
9077 {
9107 else
9108 {
9111 }
9116 }
9118 /* Returns true iff current_function_decl is an incompletely instantiated
9119 template. Useful instead of processing_template_decl because the latter
9120 is set to 0 during instantiate_non_dependent_expr. */
9122 bool
9124 {
9133 }
9135 /* Returns true if T depends on any template parameter with level LEVEL. */
9137 bool
9139 {
9142 }
9144 /* Returns true if the signature of DECL depends on any template parameter from
9145 its enclosing class. */
9147 bool
9149 {
9159 template_parm_outer_level,
9169 }
9171 /* Returns TRUE iff INST is an instantiation we don't need to do in an
9172 ill-formed translation unit, i.e. a variable or function that isn't
9173 usable in a constant expression. */
9177 {
9181 }
9183 /* Returns TRUE iff we should refuse to instantiate DECL because it's
9184 neglectable and instantiated from within an erroneous instantiation. */
9186 static bool
9188 {
9199 }
9207 /* We're starting to instantiate D; record the template instantiation context
9208 for diagnostics and to restore it later. */
9210 bool
9212 {
9214 }
9216 /* We're starting to instantiate D; record the template instantiation context
9217 at LOC for diagnostics and to restore it later. */
9219 bool
9221 {
9225 {
9226 /* Tell error.c not to try to instantiate any templates. */
9229 "template instantiation depth exceeds maximum of %d"
9231 max_tinst_depth);
9233 }
9235 /* If the current instantiation caused problems, don't let it instantiate
9236 anything else. Do allow deduction substitution and decls usable in
9237 constant expressions. */
9241 /* When not -quiet, dump template instantiations other than functions, since
9242 announce_function will take care of those. */
9261 }
9263 /* We're done instantiating this template; return to the instantiation
9264 context. */
9266 void
9268 {
9269 /* Restore the filename and line number stashed away when we started
9270 this instantiation. */
9274 }
9276 /* We're instantiating a deferred template; restore the template
9277 instantiation context in which the instantiation was requested, which
9278 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
9280 static tree
9282 {
9294 }
9296 /* Returns the TINST_LEVEL which gives the original instantiation
9297 context. */
9301 {
9307 }
9309 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
9310 vector of template arguments, as for tsubst.
9312 Returns an appropriate tsubst'd friend declaration. */
9314 static tree
9316 {
9317 tree new_friend;
9322 /* This was a friend declared with an explicit template
9323 argument list, e.g.:
9325 friend void f<>(T);
9327 to indicate that f was a template instantiation, not a new
9328 function declaration. Now, we have to figure out what
9329 instantiation of what template. */
9330 {
9332 tree new_args;
9333 tree tmpl;
9336 /* Friend functions are looked up in the containing namespace scope.
9337 We must enter that scope, to avoid finding member functions of the
9338 current class with same name. */
9353 tsk_none);
9355 }
9359 /* The NEW_FRIEND will look like an instantiation, to the
9360 compiler, but is not an instantiation from the point of view of
9361 the language. For example, we might have had:
9363 template <class T> struct S {
9364 template <class U> friend void f(T, U);
9365 };
9367 Then, in S<int>, template <class U> void f(int, U) is not an
9368 instantiation of anything. */
9374 {
9378 }
9380 /* The mangled name for the NEW_FRIEND is incorrect. The function
9381 is not a template instantiation and should not be mangled like
9382 one. Therefore, we forget the mangling here; we'll recompute it
9383 later if we need it. */
9385 {
9388 }
9391 {
9392 tree old_decl;
9393 tree new_friend_template_info;
9394 tree new_friend_result_template_info;
9395 tree ns;
9398 /* We must save some information from NEW_FRIEND before calling
9399 duplicate decls since that function will free NEW_FRIEND if
9400 possible. */
9402 new_friend_is_defn =
9407 {
9408 /* This declaration is a `primary' template. */
9411 new_friend_result_template_info
9413 }
9414 else
9417 /* Inside pushdecl_namespace_level, we will push into the
9418 current namespace. However, the friend function should go
9419 into the namespace of the template. */
9429 {
9430 /* This new friend declaration matched an existing
9431 declaration. For example, given:
9433 template <class T> void f(T);
9434 template <class U> class C {
9435 template <class T> friend void f(T) {}
9436 };
9438 the friend declaration actually provides the definition
9439 of `f', once C has been instantiated for some type. So,
9440 old_decl will be the out-of-class template declaration,
9441 while new_friend is the in-class definition.
9443 But, if `f' was called before this point, the
9444 instantiation of `f' will have DECL_TI_ARGS corresponding
9445 to `T' but not to `U', references to which might appear
9446 in the definition of `f'. Previously, the most general
9447 template for an instantiation of `f' was the out-of-class
9448 version; now it is the in-class version. Therefore, we
9449 run through all specialization of `f', adding to their
9450 DECL_TI_ARGS appropriately. In particular, they need a
9451 new set of outer arguments, corresponding to the
9452 arguments for this class instantiation.
9454 The same situation can arise with something like this:
9456 friend void f(int);
9457 template <class T> class C {
9458 friend void f(T) {}
9459 };
9461 when `C<int>' is instantiated. Now, `f(int)' is defined
9462 in the class. */
9465 /* On the other hand, if the in-class declaration does
9466 *not* provide a definition, then we don't want to alter
9467 existing definitions. We can just leave everything
9468 alone. */
9469 ;
9470 else
9471 {
9475 /* Overwrite whatever template info was there before, if
9476 any, with the new template information pertaining to
9477 the declaration. */
9481 {
9482 /* We should have called reregister_specialization in
9483 duplicate_decls. */
9488 /* Instantiate it if the global has already been used. */
9492 }
9493 else
9494 {
9495 tree t;
9497 /* Indicate that the old function template is a partial
9498 instantiation. */
9506 /* Reassign any specializations already in the hash table
9507 to the new more general template, and add the
9508 additional template args. */
9512 {
9514 spec_entry elt;
9526 register_specialization
9529 }
9531 }
9532 }
9534 /* The information from NEW_FRIEND has been merged into OLD_DECL
9535 by duplicate_decls. */
9537 }
9538 }
9539 else
9540 {
9544 /* In the code
9545 template <class T> class C {
9546 template <class U> friend void C1<U>::f (); // case 1
9547 friend void C2<T>::f (); // case 2
9548 };
9549 we only need to make sure CONTEXT is a complete type for
9550 case 2. To distinguish between the two cases, we note that
9551 CONTEXT of case 1 remains dependent type after tsubst while
9552 this isn't true for case 2. */
9562 {
9564 /* do_friend adds the TEMPLATE_DECL for any member friend
9565 template even if it isn't a member template, i.e.
9566 template <class T> friend A<T>::f();
9567 Look through it in that case. */
9571 /* Check to see that the declaration is really present, and,
9572 possibly obtain an improved declaration. */
9577 }
9578 }
9581 }
9583 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
9584 template arguments, as for tsubst.
9586 Returns an appropriate tsubst'd friend type or error_mark_node on
9587 failure. */
9589 static tree
9591 {
9592 tree friend_type;
9593 tree tmpl;
9594 tree context;
9597 {
9600 }
9605 {
9608 else
9610 }
9612 /* Look for a class template declaration. We look for hidden names
9613 because two friend declarations of the same template are the
9614 same. For example, in:
9616 struct A {
9617 template <typename> friend class F;
9618 };
9619 template <typename> struct B {
9620 template <typename> friend class F;
9621 };
9623 both F templates are the same. */
9627 /* But, if we don't find one, it might be because we're in a
9628 situation like this:
9630 template <class T>
9631 struct S {
9632 template <class U>
9633 friend struct S;
9634 };
9636 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
9637 for `S<int>', not the TEMPLATE_DECL. */
9639 {
9642 }
9645 {
9646 /* The friend template has already been declared. Just
9647 check to see that the declarations match, and install any new
9648 default parameters. We must tsubst the default parameters,
9649 of course. We only need the innermost template parameters
9650 because that is all that redeclare_class_template will look
9651 at. */
9654 {
9655 tree parms;
9656 location_t saved_input_location;
9666 }
9669 }
9670 else
9671 {
9672 /* The friend template has not already been declared. In this
9673 case, the instantiation of the template class will cause the
9674 injection of this template into the global scope. */
9679 /* The new TMPL is not an instantiation of anything, so we
9680 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
9681 the new type because that is supposed to be the corresponding
9682 template decl, i.e., TMPL. */
9689 /* Inject this template into the global scope. */
9691 }
9694 {
9697 else
9699 }
9702 }
9704 /* Returns zero if TYPE cannot be completed later due to circularity.
9705 Otherwise returns one. */
9707 static int
9709 {
9719 else
9721 }
9726 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
9727 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
9729 static tree
9732 {
9741 {
9748 clauses
9752 else
9754 }
9755 /* If the first attribute argument is an identifier, don't
9756 pass it through tsubst. Attributes like mode, format,
9757 cleanup and several target specific attributes expect it
9758 unmodified. */
9760 {
9761 tree chain
9766 }
9768 {
9769 /* An attribute pack expansion. */
9776 {
9780 }
9782 }
9783 else
9790 }
9792 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
9793 unchanged or a new TREE_LIST chain. */
9795 static tree
9798 {
9803 {
9807 }
9811 {
9814 {
9817 {
9819 do
9824 }
9825 }
9827 }
9830 }
9832 /* Apply any attributes which had to be deferred until instantiation
9833 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
9834 ARGS, COMPLAIN, IN_DECL are as tsubst. */
9836 static void
9839 {
9841 tree t;
9846 {
9850 }
9853 {
9857 }
9858 else
9862 {
9867 {
9870 {
9874 do
9877 }
9878 else
9880 }
9883 }
9884 }
9886 /* Perform (or defer) access check for typedefs that were referenced
9887 from within the template TMPL code.
9888 This is a subroutine of instantiate_decl and instantiate_class_template.
9889 TMPL is the template to consider and TARGS is the list of arguments of
9890 that template. */
9892 static void
9894 {
9895 location_t saved_location;
9906 {
9918 /* Make access check error messages point to the location
9919 of the use of the typedef. */
9923 tf_warning_or_error);
9924 }
9926 }
9928 static tree
9930 {
9932 tree typedecl;
9933 tree pbinfo;
9934 tree base_list;
9936 tree fn_context;
9945 /* Figure out which template is being instantiated. */
9949 /* Determine what specialization of the original template to
9950 instantiate. */
9953 {
9956 }
9958 {
9959 /* This TYPE is actually an instantiation of a partial
9960 specialization. We replace the innermost set of ARGS with
9961 the arguments appropriate for substitution. For example,
9962 given:
9964 template <class T> struct S {};
9965 template <class T> struct S<T*> {};
9967 and supposing that we are instantiating S<int*>, ARGS will
9968 presently be {int*} -- but we need {int}. */
9971 }
9972 else
9973 {
9976 }
9978 /* If the template we're instantiating is incomplete, then clearly
9979 there's nothing we can do. */
9983 /* If we've recursively instantiated too many templates, stop. */
9987 /* Now we're really doing the instantiation. Mark the type as in
9988 the process of being defined. */
9991 /* We may be in the middle of deferred access check. Disable
9992 it now. */
9999 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10004 else
10005 {
10008 }
10009 /* Use #pragma pack from the template context. */
10015 /* Set the input location to the most specialized template definition.
10016 This is needed if tsubsting causes an error. */
10027 {
10030 /* Adjust visibility for template arguments. */
10032 }
10038 /* We should never instantiate a nested class before its enclosing
10039 class; we need to look up the nested class by name before we can
10040 instantiate it, and that lookup should instantiate the enclosing
10041 class. */
10047 {
10048 tree pbase_binfo;
10049 tree pushed_scope;
10052 /* We must enter the scope containing the type, as that is where
10053 the accessibility of types named in dependent bases are
10054 looked up from. */
10057 /* Substitute into each of the bases to determine the actual
10058 basetypes. */
10060 {
10061 tree base;
10067 {
10068 expanded_bases =
10075 }
10078 {
10080 /* Extract the already-expanded base class. */
10082 else
10083 /* Substitute to figure out the base class. */
10085 NULL_TREE);
10093 }
10094 }
10096 /* The list is now in reverse order; correct that. */
10101 }
10102 /* Now call xref_basetypes to set up all the base-class
10103 information. */
10111 /* Now that our base classes are set up, enter the scope of the
10112 class, so that name lookups into base classes, etc. will work
10113 correctly. This is precisely analogous to what we do in
10114 begin_class_definition when defining an ordinary non-template
10115 class, except we also need to push the enclosing classes. */
10118 /* Now members are processed in the order of declaration. */
10121 {
10125 {
10127 {
10128 /* Build new CLASSTYPE_NESTED_UTDS. */
10130 tree newtag;
10136 /* If the member is a class template, then -- even after
10137 substitution -- there may be dependent types in the
10138 template argument list for the class. We increment
10139 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
10140 that function will assume that no types are dependent
10141 when outside of a template. */
10151 {
10155 /* Unfortunately, lookup_template_class sets
10156 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
10157 instantiation (i.e., for the type of a member
10158 template class nested within a template class.)
10159 This behavior is required for
10160 maybe_process_partial_specialization to work
10161 correctly, but is not accurate in this case;
10162 the TAG is not an instantiation of anything.
10163 (The corresponding TEMPLATE_DECL is an
10164 instantiation, but the TYPE is not.) */
10167 /* Now, we call pushtag to put this NEWTAG into the scope of
10168 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
10169 pushtag calling push_template_decl. We don't have to do
10170 this for enums because it will already have been done in
10171 tsubst_enum. */
10175 }
10176 }
10178 {
10179 /* Build new TYPE_METHODS. */
10180 tree r;
10189 /* Instantiate members marked with attribute used. */
10195 }
10198 /* A closure type for a lambda in a default argument for a
10199 member template. Ignore it; it will be instantiated with
10201 else
10202 {
10203 /* Build new TYPE_FIELDS. */
10205 {
10206 tree condition;
10209 condition =
10219 }
10221 {
10222 tree r;
10226 /* The file and line for this declaration, to
10227 assist in error message reporting. Since we
10228 called push_tinst_level above, we don't need to
10229 restore these. */
10239 {
10240 /* A capture pack became multiple fields. */
10243 }
10246 {
10250 {
10251 /* In [temp.inst]:
10253 [t]he initialization (and any associated
10254 side-effects) of a static data member does
10255 not occur unless the static data member is
10256 itself used in a way that requires the
10257 definition of the static data member to
10258 exist.
10260 Therefore, we do not substitute into the
10261 initialized for the static data member here. */
10262 finish_static_data_member_decl
10268 /* Instantiate members marked with attribute used. */
10271 }
10273 {
10274 /* Determine whether R has a valid type and can be
10275 completed later. If R is invalid, then its type
10276 is replaced by error_mark_node. */
10282 {
10283 /* If R's type couldn't be completed and
10284 it isn't a flexible array member (whose
10285 type is incomplete by definition) give
10286 an error. */
10289 }
10290 }
10292 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10293 such a thing will already have been added to the field
10294 list by tsubst_enum in finish_member_declaration in the
10295 CLASSTYPE_NESTED_UTDS case above. */
10299 {
10302 }
10303 }
10304 }
10305 }
10306 }
10307 else
10308 {
10311 {
10312 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10318 {
10319 /* template <class T> friend class C; */
10322 }
10324 {
10325 /* template <class T> friend class C::D; */
10331 }
10334 {
10335 /* This could be either
10337 friend class T::C;
10339 when dependent_type_p is false or
10341 template <class U> friend class T::C;
10343 otherwise. */
10344 /* Bump processing_template_decl in case this is something like
10345 template <class T> friend struct A<T>::B. */
10352 }
10355 {
10356 /* friend class C;
10358 where C hasn't been declared yet. Let's lookup name
10359 from namespace scope directly, bypassing any name that
10360 come from dependent base class. */
10363 /* The call to xref_tag_from_type does injection for friend
10364 classes. */
10366 friend_type =
10370 }
10372 /* friend class C<T>; */
10375 /* Otherwise it's
10377 friend class C;
10379 where C is already declared or
10381 friend class C<int>;
10383 We don't have to do anything in these cases. */
10386 /* Trick make_friend_class into realizing that the friend
10387 we're adding is a template, not an ordinary class. It's
10388 important that we use make_friend_class since it will
10389 perform some error-checking and output cross-reference
10390 information. */
10398 }
10399 else
10400 {
10401 /* Build new DECL_FRIENDLIST. */
10402 tree r;
10404 /* The file and line for this declaration, to
10405 assist in error message reporting. Since we
10406 called push_tinst_level above, we don't need to
10407 restore these. */
10411 {
10414 }
10419 {
10422 }
10423 }
10424 }
10425 }
10428 {
10429 /* Restore these before substituting into the lambda capture
10430 initializers. */
10433 }
10436 {
10439 {
10445 {
10446 /* Set function_depth to avoid garbage collection. */
10450 }
10452 /* We need to instantiate the capture list from the template
10453 after we've instantiated the closure members, but before we
10454 consider adding the conversion op. Also keep any captures
10455 that may have been added during instantiation of the op(). */
10457 tree tmpl_cap
10466 }
10467 else
10469 }
10471 /* Set the file and line number information to whatever is given for
10472 the class itself. This puts error messages involving generated
10473 implicit functions at a predictable point, and the same point
10474 that would be used for non-template classes. */
10481 /* We don't instantiate default arguments for member functions. 14.7.1:
10483 The implicit instantiation of a class template specialization causes
10484 the implicit instantiation of the declarations, but not of the
10485 definitions or default arguments, of the class member functions,
10486 member classes, static data members and member templates.... */
10488 /* Some typedefs referenced from within the template code need to be access
10489 checked at template instantiation time, i.e now. These types were
10490 added to the template at parsing time. Let's get those and perform
10491 the access checks then. */
10501 /* The vtable for a template class can be emitted in any translation
10502 unit in which the class is instantiated. When there is no key
10503 method, however, finish_struct_1 will already have added TYPE to
10504 the keyed_classes list. */
10509 }
10511 /* Wrapper for instantiate_class_template_1. */
10513 tree
10515 {
10516 tree ret;
10521 }
10523 static tree
10525 {
10526 tree r;
10532 else
10533 {
10540 }
10542 }
10544 /* Given a function parameter pack TMPL_PARM and some function parameters
10545 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
10546 and set *SPEC_P to point at the next point in the list. */
10548 tree
10550 {
10551 /* Collect all of the extra "packed" parameters into an
10552 argument pack. */
10553 tree parmvec;
10554 tree parmtypevec;
10565 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
10570 {
10573 }
10575 /* Build the argument packs. */
10582 }
10584 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
10585 NONTYPE_ARGUMENT_PACK. */
10587 static tree
10589 {
10591 }
10593 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
10594 pack expansion with no extra args, 2 if it has extra args, or 0
10595 if it is not a pack expansion. */
10597 static int
10599 {
10605 /* A decl pack is itself an expansion. */
10612 }
10615 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
10617 static tree
10619 {
10626 }
10628 /* This is a subroutine of tsubst_pack_expansion.
10630 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
10631 mechanism to store the (non complete list of) arguments of the
10632 substitution and return a non substituted pack expansion, in order
10633 to wait for when we have enough arguments to really perform the
10634 substitution. */
10636 static bool
10640 {
10641 /* If one pack has an expansion and another pack has a normal
10642 argument or if one pack has an empty argument and an another
10643 one hasn't then tsubst_pack_expansion cannot perform the
10644 substitution and need to fall back on the
10645 PACK_EXPANSION_EXTRA mechanism. */
10653 {
10656 parm_pack;
10658 {
10663 /* We can't substitute a pack expansion with extra args into
10664 our pattern. */
10668 else
10670 }
10674 }
10676 }
10678 /* [temp.variadic]/6 says that:
10680 The instantiation of a pack expansion [...]
10681 produces a list E1,E2, ..., En, where N is the number of elements
10682 in the pack expansion parameters.
10684 This subroutine of tsubst_pack_expansion produces one of these Ei.
10686 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
10687 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
10688 PATTERN, and each TREE_VALUE is its corresponding argument pack.
10689 INDEX is the index 'i' of the element Ei to produce. ARGS,
10690 COMPLAIN, and IN_DECL are the same parameters as for the
10691 tsubst_pack_expansion function.
10693 The function returns the resulting Ei upon successful completion,
10694 or error_mark_node.
10696 Note that this function possibly modifies the ARGS parameter, so
10697 it's the responsibility of the caller to restore it. */
10699 static tree
10701 tree parm_packs,
10703 tree args /* This parm gets
10705 tsubst_flags_t complain,
10706 tree in_decl)
10707 {
10708 tree t;
10711 /* For each parameter pack, change the substitution of the parameter
10712 pack to the ith argument in its argument pack, then expand the
10713 pattern. */
10715 {
10720 ith_elem_is_expansion |=
10723 /* Select the Ith argument from the pack. */
10726 {
10728 {
10733 }
10734 else
10736 }
10737 else
10738 {
10743 {
10745 /* Update the corresponding argument. */
10747 }
10748 else
10749 /* Re-use the ARGUMENT_PACK_SELECT. */
10751 }
10753 }
10755 /* Substitute into the PATTERN with the (possibly altered)
10756 arguments. */
10758 /* Expanding a fixed parameter pack from
10759 coerce_template_parameter_pack. */
10764 {
10767 else
10770 }
10774 else
10777 /* If the Ith argument pack element is a pack expansion, then
10778 the Ith element resulting from the substituting is going to
10779 be a pack expansion as well. */
10784 }
10786 /* When the unexpanded parameter pack in a fold expression expands to an empty
10787 sequence, the value of the expression is as follows; the program is
10788 ill-formed if the operator is not listed in this table.
10790 && true
10791 || false
10792 , void() */
10794 tree
10796 {
10800 {
10809 }
10815 }
10817 /* Given a fold-expression T and a current LEFT and RIGHT operand,
10818 form an expression that combines the two terms using the
10819 operator of T. */
10821 static tree
10823 {
10827 // Handle compound assignment operators.
10832 {
10842 complain);
10843 }
10844 }
10846 /* Substitute ARGS into the pack of a fold expression T. */
10850 {
10852 }
10854 /* Substitute ARGS into the pack of a fold expression T. */
10858 {
10860 }
10862 /* Expand a PACK of arguments into a grouped as left fold.
10863 Given a pack containing elements A0, A1, ..., An and an
10864 operator @, this builds the expression:
10866 ((A0 @ A1) @ A2) ... @ An
10868 Note that PACK must not be empty.
10870 The operator is defined by the original fold expression T. */
10872 static tree
10874 {
10877 {
10880 }
10882 }
10884 /* Substitute into a unary left fold expression. */
10886 static tree
10888 tree in_decl)
10889 {
10894 {
10898 }
10901 else
10903 }
10905 /* Substitute into a binary left fold expression.
10907 Do ths by building a single (non-empty) vector of argumnts and
10908 building the expression from those elements. */
10910 static tree
10912 tree in_decl)
10913 {
10922 {
10927 }
10935 }
10937 /* Expand a PACK of arguments into a grouped as right fold.
10938 Given a pack containing elementns A0, A1, ..., and an
10939 operator @, this builds the expression:
10941 A0@ ... (An-2 @ (An-1 @ An))
10943 Note that PACK must not be empty.
10945 The operator is defined by the original fold expression T. */
10947 tree
10949 {
10950 // Build the expression.
10954 {
10957 }
10959 }
10961 /* Substitute into a unary right fold expression. */
10963 static tree
10965 tree in_decl)
10966 {
10971 {
10975 }
10978 else
10980 }
10982 /* Substitute into a binary right fold expression.
10984 Do ths by building a single (non-empty) vector of arguments and
10985 building the expression from those elements. */
10987 static tree
10989 tree in_decl)
10990 {
10999 {
11004 }
11013 }
11016 /* Substitute ARGS into T, which is an pack expansion
11017 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
11018 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
11019 (if only a partial substitution could be performed) or
11020 ERROR_MARK_NODE if there was an error. */
11021 tree
11023 tree in_decl)
11024 {
11025 tree pattern;
11029 tree result;
11037 /* Add in any args remembered from an earlier partial instantiation. */
11042 /* Determine the argument packs that will instantiate the parameter
11043 packs used in the expansion expression. While we're at it,
11044 compute the number of arguments to be expanded and make sure it
11045 is consistent. */
11048 {
11055 {
11059 else
11062 }
11064 {
11065 /* We know we have correct local_specializations if this
11066 expansion is at function scope, or if we're dealing with a
11067 local parameter in a requires expression; for the latter,
11068 tsubst_requires_expr set it up appropriately. */
11071 else
11072 /* We can't rely on local_specializations for a parameter
11073 name used later in a function declaration (such as in a
11074 late-specified return type). Even if it exists, it might
11075 have the wrong value for a recursive call. */
11079 {
11080 /* This parameter pack was used in an unevaluated context. Just
11081 make a dummy decl, since it's only used for its type. */
11084 /* Partial instantiation of the parm_pack, we can't build
11085 up an argument pack yet. */
11087 else
11089 }
11090 }
11093 else
11094 {
11100 }
11107 /* This can only happen if we forget to expand an argument
11108 pack somewhere else. Just return an error, silently. */
11109 {
11113 }
11116 {
11120 /* Don't bother trying to do a partial substitution with
11121 incomplete packs; we'll try again after deduction. */
11128 {
11134 pattern);
11135 else
11138 pattern);
11140 }
11142 /* Keep track of the parameter packs and their corresponding
11143 argument packs. */
11146 }
11147 else
11148 {
11149 /* We can't substitute for this parameter pack. We use a flag as
11150 well as the missing_level counter because function parameter
11151 packs don't have a level. */
11154 }
11155 }
11157 /* If the expansion is just T..., return the matching argument pack, unless
11158 we need to call convert_from_reference on all the elements. This is an
11159 important optimization; see c++/68422. */
11162 {
11164 /* Types need no adjustment, nor does sizeof..., and if we still have
11165 some pack expansion args we won't do anything yet. */
11170 /* Also optimize expression pack expansions if we can tell that the
11171 elements won't have reference type. */
11177 /* Otherwise use the normal path so we get convert_from_reference. */
11178 }
11180 /* We cannot expand this expansion expression, because we don't have
11181 all of the argument packs we need. */
11183 {
11184 /* We got some full packs, but we can't substitute them in until we
11185 have values for all the packs. So remember these until then. */
11190 }
11192 {
11193 /* There were no real arguments, we're just replacing a parameter
11194 pack with another version of itself. Substitute into the
11195 pattern and return a PACK_EXPANSION_*. The caller will need to
11196 deal with that. */
11200 else
11204 }
11209 {
11210 /* We're in a late-specified return type, so create our own local
11211 specializations map; the current map is either NULL or (in the
11212 case of recursive unification) might have bindings that we don't
11213 want to use or alter. */
11216 }
11218 /* For each argument in each argument pack, substitute into the
11219 pattern. */
11223 {
11225 i,
11227 in_decl);
11230 {
11233 }
11234 }
11236 /* Update ARGS to restore the substitution from parameter packs to
11237 their argument packs. */
11239 {
11245 else
11246 {
11254 /* Update the corresponding argument. */
11258 else
11260 }
11261 }
11264 {
11267 }
11269 /* If the dependent pack arguments were such that we end up with only a
11270 single pack expansion again, there's no need to keep it in a TREE_VEC. */
11276 }
11278 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
11279 TMPL. We do this using DECL_PARM_INDEX, which should work even with
11280 parameter packs; all parms generated from a function parameter pack will
11281 have the same DECL_PARM_INDEX. */
11283 tree
11285 {
11287 tree patparm;
11290 {
11296 }
11297 else
11298 {
11303 }
11306 }
11308 /* Make an argument pack out of the TREE_VEC VEC. */
11310 static tree
11312 {
11313 tree pack;
11317 else
11318 {
11322 }
11325 }
11327 /* Return an exact copy of template args T that can be modified
11328 independently. */
11330 static tree
11332 {
11340 {
11345 }
11351 }
11353 /* Substitute ARGS into the vector or list of template arguments T. */
11355 static tree
11357 {
11369 {
11371 tree new_arg;
11376 {
11377 /* Substitute into an expansion expression. */
11381 /* Add to the expanded length adjustment the number of
11382 expanded arguments. We subtract one from this
11383 measurement, because the argument pack expression
11384 itself is already counted as 1 in
11385 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
11386 the argument pack is empty. */
11388 }
11390 {
11391 /* Substitute into each of the arguments. */
11397 new_arg,
11411 }
11412 }
11413 else
11422 }
11427 /* Make space for the expanded arguments coming from template
11428 argument packs. */
11430 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
11431 arguments for a member template.
11432 In that case each TREE_VEC in ORIG_T represents a level of template
11433 arguments, and ORIG_T won't carry any non defaulted argument count.
11434 It will rather be the nested TREE_VECs that will carry one.
11435 In other words, ORIG_T carries a non defaulted argument count only
11436 if it doesn't contain any nested TREE_VEC. */
11438 {
11442 }
11444 {
11448 {
11451 /* Now expand the template argument pack "in place". */
11454 }
11455 else
11456 {
11458 out++;
11459 }
11460 }
11463 }
11465 /* Substitute ARGS into one level PARMS of template parameters. */
11467 static tree
11469 {
11476 {
11484 }
11487 }
11489 /* Return the result of substituting ARGS into the template parameters
11490 given by PARMS. If there are m levels of ARGS and m + n levels of
11491 PARMS, then the result will contain n levels of PARMS. For
11492 example, if PARMS is `template <class T> template <class U>
11493 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
11494 result will be `template <int*, double, class V>'. */
11496 static tree
11498 {
11502 /* When substituting into a template, we must set
11503 PROCESSING_TEMPLATE_DECL as the template parameters may be
11504 dependent if they are based on one-another, and the dependency
11505 predicates are short-circuit outside of templates. */
11512 {
11519 }
11524 }
11526 /* Return the result of substituting ARGS into one template parameter
11527 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
11528 parameter and which TREE_PURPOSE is the default argument of the
11529 template parameter. */
11531 static tree
11533 {
11554 }
11556 /* Substitute the ARGS into the indicated aggregate (or enumeration)
11557 type T. If T is not an aggregate or enumeration type, it is
11558 handled as if by tsubst. IN_DECL is as for tsubst. If
11559 ENTERING_SCOPE is nonzero, T is the context for a template which
11560 we are presently tsubst'ing. Return the substituted value. */
11562 static tree
11564 tree args,
11565 tsubst_flags_t complain,
11566 tree in_decl,
11568 {
11573 {
11578 /* Fall through. */
11582 {
11583 tree argvec;
11584 tree context;
11585 tree r;
11589 /* In "sizeof(X<I>)" we need to evaluate "I". */
11595 /* First, determine the context for the type we are looking
11596 up. */
11599 {
11602 /* If context is a nested class inside a class template,
11603 it may still need to be instantiated (c++/33959). */
11605 }
11607 /* Then, figure out what arguments are appropriate for the
11608 type we are trying to find. For example, given:
11610 template <class T> struct S;
11611 template <class T, class U> void f(T, U) { S<U> su; }
11613 and supposing that we are instantiating f<int, double>,
11614 then our ARGS will be {int, double}, but, when looking up
11615 S we only want {double}. */
11620 else
11621 {
11625 }
11631 }
11632 else
11633 /* This is not a template type, so there's nothing to do. */
11638 }
11639 }
11641 /* Substitute into the default argument ARG (a default argument for
11642 FN), which has the indicated TYPE. */
11644 tree
11646 {
11651 /* This can happen in invalid code. */
11655 /* This default argument came from a template. Instantiate the
11656 default argument here, not in tsubst. In the case of
11657 something like:
11659 template <class T>
11660 struct S {
11661 static T t();
11662 void f(T = t());
11663 };
11665 we must be careful to do name lookup in the scope of S<T>,
11666 rather than in the current class. */
11668 /* The "this" pointer is not valid in a default argument. */
11670 {
11675 }
11678 /* The default argument expression may cause implicitly defined
11679 member functions to be synthesized, which will result in garbage
11680 collection. We must treat this situation as if we were within
11681 the body of function so as to avoid collecting live data on the
11682 stack. */
11690 /* Restore the "this" pointer. */
11692 {
11695 }
11702 /* Make sure the default argument is reasonable. */
11708 }
11710 /* Substitute into all the default arguments for FN. */
11712 static void
11714 {
11715 tree arg;
11716 tree tmpl_args;
11720 /* If this function is not yet instantiated, we certainly don't need
11721 its default arguments. */
11724 /* Don't do this again for clones. */
11729 arg;
11735 complain);
11736 }
11738 /* Substitute the ARGS into the T, which is a _DECL. Return the
11739 result of the substitution. Issue error and warning messages under
11740 control of COMPLAIN. */
11742 static tree
11744 {
11745 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
11746 location_t saved_loc;
11751 /* Set the filename and linenumber to improve error-reporting. */
11756 {
11758 {
11759 /* We can get here when processing a member function template,
11760 member class template, or template template parameter. */
11762 tree spec;
11763 tree tmpl_args;
11764 tree full_args;
11767 {
11768 /* Template template parameter is treated here. */
11772 /* If we get a real template back, return it. This can happen in
11773 the context of most_specialized_partial_spec. */
11776 else
11777 /* The new TEMPLATE_DECL was built in
11778 reduce_template_parm_level. */
11781 }
11783 /* We might already have an instance of this template.
11784 The ARGS are for the surrounding class type, so the
11785 full args contain the tsubst'd args for the context,
11786 plus the innermost args from the template decl. */
11790 /* Because this is a template, the arguments will still be
11791 dependent, even after substitution. If
11792 PROCESSING_TEMPLATE_DECL is not set, the dependency
11793 predicates will short-circuit. */
11801 /* If this is a default template template argument,
11802 tsubst might not have changed anything. */
11809 {
11812 }
11814 /* Make a new template decl. It will be similar to the
11815 original, but will record the current template arguments.
11816 We also create a new function declaration, which is just
11817 like the old one, but points to this new template, rather
11818 than the old one. */
11823 // Build new template info linking to the original template decl.
11828 {
11829 tree new_type;
11837 /* For a partial specialization, we need to keep pointing to
11838 the primary template. */
11844 }
11845 else
11846 {
11847 tree new_decl;
11859 }
11865 /* The template parameters for this new template are all the
11866 template parameters for the old template, except the
11867 outermost level of parameters. */
11870 complain);
11876 /* Record this non-type partial instantiation. */
11880 }
11884 {
11885 tree ctx;
11888 tree gen_tmpl;
11889 tree type;
11894 /* Nobody should be tsubst'ing into non-template functions. */
11898 {
11899 tree spec;
11901 /* If T is not dependent, just return it. */
11905 /* Calculate the most general template of which R is a
11906 specialization, and the complete set of arguments used to
11907 specialize R. */
11910 (DECL_TEMPLATE_RESULT
11916 /* Check to see if we already have this specialization. */
11921 {
11924 }
11926 /* We can see more levels of arguments than parameters if
11927 there was a specialization of a member template, like
11928 this:
11930 template <class T> struct S { template <class U> void f(); }
11931 template <> template <class U> void S<int>::f(U);
11933 Here, we'll be substituting into the specialization,
11934 because that's where we can find the code we actually
11935 want to generate, but we'll have enough arguments for
11936 the most general template.
11938 We also deal with the peculiar case:
11940 template <class T> struct S {
11941 template <class U> friend void f();
11942 };
11943 template <class U> void f() {}
11944 template S<int>;
11945 template void f<double>();
11947 Here, the ARGS for the instantiation of will be {int,
11948 double}. But, we only need as many ARGS as there are
11949 levels of template parameters in CODE_PATTERN. We are
11950 careful not to get fooled into reducing the ARGS in
11951 situations like:
11953 template <class T> struct S { template <class U> void f(U); }
11954 template <class T> template <> void S<T>::f(int) {}
11956 which we can spot because the pattern will be a
11957 specialization in this case. */
11959 parms_depth =
11964 }
11965 else
11966 {
11967 /* This special case arises when we have something like this:
11969 template <class T> struct S {
11970 friend void f<int>(int, double);
11971 };
11973 Here, the DECL_TI_TEMPLATE for the friend declaration
11974 will be an IDENTIFIER_NODE. We are being called from
11975 tsubst_friend_function, and we want only to create a
11976 new decl (R) with appropriate types so that we can call
11977 determine_specialization. */
11979 }
11982 {
11985 else
11989 }
11990 else
11991 {
11994 }
11999 /* If we hit excessive deduction depth, the type is bogus even if
12000 it isn't error_mark_node, so don't build a decl. */
12004 /* We do NOT check for matching decls pushed separately at this
12005 point, as they may not represent instantiations of this
12006 template, and in any case are considered separate under the
12007 discrete model. */
12011 /* Clear out the mangled name and RTL for the instantiation. */
12014 /* Leave DECL_INITIAL set on deleted instantiations. */
12019 /* OpenMP UDRs have the only argument a reference to the declared
12020 type. We want to diagnose if the declared type is a reference,
12021 which is invalid, but as references to references are usually
12022 quietly merged, diagnose it here. */
12024 {
12025 tree argtype
12030 "reference type %qT in "
12034 argtype);
12035 }
12038 /* Type-conversion operator. Reconstruct the name, in
12039 case it's the name of one of the template's parameters. */
12049 /* If this is an instantiation of a function with internal
12050 linkage, we already know what object file linkage will be
12051 assigned to the instantiation. */
12060 /* We'll re-clone as appropriate in instantiate_template. */
12063 /* If we aren't complaining now, return on error before we register
12064 the specialization so that we'll complain eventually. */
12070 /* When instantiating a constrained member, substitute
12071 into the constraints to create a new constraint. */
12074 {
12077 }
12079 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
12080 this in the special friend case mentioned above where
12081 GEN_TMPL is NULL. */
12083 {
12088 tree new_r
12091 /* We instantiated this while substituting into
12092 the type earlier (template/friend54.C). */
12095 /* We're not supposed to instantiate default arguments
12096 until they are called, for a template. But, for a
12097 declaration like:
12099 template <class T> void f ()
12100 { extern void g(int i = T()); }
12102 we should do the substitution when the template is
12103 instantiated. We handle the member function case in
12104 instantiate_class_template since the default arguments
12105 might refer to other members of the class. */
12110 }
12111 else
12114 /* Copy the list of befriending classes. */
12118 {
12122 in_decl);
12123 }
12126 {
12132 /* If this is an instantiation of a member template, clone it.
12133 If it isn't, that'll be handled by
12134 clone_constructors_and_destructors. */
12137 }
12148 /* Possibly limit visibility based on template args. */
12151 {
12155 }
12163 }
12167 {
12175 {
12176 /* If there is a local specialization that isn't a
12177 parameter pack, it means that we're doing a "simple"
12178 substitution from inside tsubst_pack_expansion. Just
12179 return the local specialization (which will be a single
12180 parm). */
12187 /* Expand the TYPE_PACK_EXPANSION that provides the types for
12188 the parameters in this function parameter pack. */
12192 {
12195 /* Zero-length parameter packs are boring. Just substitute
12196 into the chain. */
12200 }
12201 else
12202 {
12203 /* All we did was update the type. Make a note of that. */
12206 }
12207 }
12209 /* Loop through all of the parameters we'll build. When T is
12210 a function parameter pack, LEN is the number of expanded
12211 types in EXPANDED_TYPES; otherwise, LEN is 1. */
12214 {
12221 /* We're on the Ith parameter of the function parameter
12222 pack. */
12223 {
12224 /* Get the Ith type. */
12227 /* Rename the parameter to include the index. */
12230 }
12232 /* We're dealing with a normal parameter. */
12240 {
12243 else
12246 }
12256 /* Keep track of the first new parameter we
12257 generate. That's what will be returned to the
12258 caller. */
12262 /* Build a proper chain of parameters when substituting
12263 into a function parameter pack. */
12266 }
12268 /* If cp_unevaluated_operand is set, we're just looking for a
12269 single dummy parameter, so don't keep going. */
12274 /* FIRST_R contains the start of the chain we've built. */
12276 }
12280 {
12287 {
12288 /* This field is a lambda capture pack. Return a TREE_VEC of
12289 the expanded fields to instantiate_class_template_1 and
12290 store them in the specializations hash table as a
12291 NONTYPE_ARGUMENT_PACK so that tsubst_copy can find them. */
12295 {
12298 }
12299 else
12300 {
12301 /* All we did was update the type. Make a note of that. */
12304 }
12305 }
12308 {
12311 {
12315 }
12325 /* For bit-fields, DECL_INITIAL gives the number of bits. For
12326 non-bit-fields DECL_INITIAL is a non-static data member
12327 initializer, which gets deferred instantiation. */
12333 {
12334 /* Set up DECL_TEMPLATE_INFO so that we can get at the
12335 NSDMI in perform_member_init. Still set DECL_INITIAL
12336 so that we know there is one. */
12341 }
12342 /* We don't have to set DECL_CONTEXT here; it is set by
12343 finish_member_declaration. */
12351 }
12354 {
12362 }
12363 }
12367 /* We reach here only for member using decls. We also need to check
12368 uses_template_parms because DECL_DEPENDENT_P is not set for a
12369 using-declaration that designates a member of the current
12370 instantiation (c++/53549). */
12373 {
12380 else
12381 {
12384 }
12385 }
12386 else
12387 {
12390 }
12395 {
12398 tree spec;
12400 tree ctx;
12409 {
12410 /* If this is the canonical decl, we don't have to
12411 mess with instantiations, and often we can't (for
12412 typename, template type parms and such). Note that
12413 TYPE_NAME is not correct for the above test if
12414 we've copied the type for a typedef. */
12420 }
12422 /* Check to see if we already have the specialization we
12423 need. */
12426 {
12427 /* T is a static data member or namespace-scope entity.
12428 We have to substitute into namespace-scope variables
12429 (not just variable templates) because of cases like:
12431 template <class T> void f() { extern T t; }
12433 where the entity referenced is not known until
12434 instantiation time. */
12438 {
12440 complain,
12442 /* If CTX is unchanged, then T is in fact the
12443 specialization we want. That situation occurs when
12444 referencing a static data member within in its own
12445 class. We can use pointer equality, rather than
12446 same_type_p, because DECL_CONTEXT is always
12447 canonical... */
12449 /* ... unless T is a member template; in which
12450 case our caller can be willing to create a
12451 specialization of that template represented
12452 by T. */
12456 }
12459 {
12464 argvec = (coerce_innermost_template_parms
12472 }
12473 }
12474 else
12475 {
12476 /* A local variable. */
12478 /* Subsequent calls to pushdecl will fill this in. */
12480 /* Unless this is a reference to a static variable from an
12481 enclosing function, in which case we need to fill it in now. */
12483 {
12487 }
12489 }
12490 /* If we already have the specialization we need, there is
12491 nothing more to do. */
12493 {
12496 }
12498 /* Create a new node for the specialization we need. */
12501 {
12504 else
12511 }
12513 {
12514 /* Even if the original location is out of scope, the
12515 newly substituted one is not. */
12522 {
12523 /* It may seem that this case cannot occur, since:
12525 typedef void f();
12526 void g() { f x; }
12528 declares a function, not a variable. However:
12530 typedef void f();
12531 template <typename T> void g() { T t; }
12532 template void g<f>();
12534 is an attempt to declare a variable with function
12535 type. */
12537 /* R is not yet sufficiently initialized, so we
12538 just use its name. */
12541 }
12543 /* Wait until cp_finish_decl to set this again, to handle
12544 circular dependency (template/instantiate6.C). */
12549 {
12554 {
12557 }
12559 }
12563 }
12569 /* Clear out the mangled name and RTL for the instantiation. */
12573 /* The initializer must not be expanded until it is required;
12574 see [temp.inst]. */
12582 {
12583 /* Possibly limit visibility based on template args. */
12586 {
12590 }
12592 }
12595 {
12596 /* A static data member declaration is always marked
12597 external when it is declared in-class, even if an
12598 initializer is present. We mimic the non-template
12599 processing here. */
12607 }
12608 else
12609 {
12614 }
12622 /* Preserve a typedef that names a type. */
12624 {
12628 /* An alias template specialization can be dependent
12629 even if its underlying type is not. */
12631 }
12634 }
12639 }
12640 #undef RETURN
12642 out:
12643 /* Restore the file and line information. */
12647 }
12649 /* Substitute into the ARG_TYPES of a function type.
12650 If END is a TREE_CHAIN, leave it and any following types
12651 un-substituted. */
12653 static tree
12655 tree args,
12656 tree end,
12657 tsubst_flags_t complain,
12658 tree in_decl)
12659 {
12660 tree remaining_arg_types;
12664 tree default_arg;
12675 {
12676 /* For a pack expansion, perform substitution on the
12677 entire expression. Later on, we'll handle the arguments
12678 one-by-one. */
12683 /* So that we'll spin through the parameters, one by one. */
12685 else
12686 {
12687 /* We only partially substituted into the parameter
12688 pack. Our type is TYPE_PACK_EXPANSION. */
12691 }
12692 }
12705 {
12707 {
12711 }
12713 }
12714 /* DR 657. */
12718 /* Do array-to-pointer, function-to-pointer conversion, and ignore
12719 top-level qualifiers as required. */
12722 /* We do not substitute into default arguments here. The standard
12723 mandates that they be instantiated only when needed, which is
12724 done in build_over_call. */
12728 {
12729 /* We've instantiated a template before its default arguments
12730 have been parsed. This can happen for a nested template
12731 class, and is not an error unless we require the default
12732 argument in a call of this function. */
12733 remaining_arg_types =
12736 }
12737 else
12738 remaining_arg_types =
12740 }
12743 }
12745 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
12746 *not* handle the exception-specification for FNTYPE, because the
12747 initial substitution of explicitly provided template parameters
12748 during argument deduction forbids substitution into the
12749 exception-specification:
12751 [temp.deduct]
12753 All references in the function type of the function template to the
12754 corresponding template parameters are replaced by the specified tem-
12755 plate argument values. If a substitution in a template parameter or
12756 in the function type of the function template results in an invalid
12757 type, type deduction fails. [Note: The equivalent substitution in
12758 exception specifications is done only when the function is instanti-
12759 ated, at which point a program is ill-formed if the substitution
12760 results in an invalid type.] */
12762 static tree
12764 tree args,
12765 tsubst_flags_t complain,
12766 tree in_decl)
12767 {
12768 tree return_type;
12770 tree fntype;
12772 /* The TYPE_CONTEXT is not used for function/method types. */
12775 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
12776 failure. */
12780 {
12781 /* Substitute the argument types. */
12793 {
12794 /* DR 1207: 'this' is in scope in the trailing return type. */
12796 }
12798 /* Substitute the return type. */
12802 {
12805 }
12806 }
12807 else
12808 /* Substitute the return type. */
12813 /* DR 486 clarifies that creation of a function type with an
12814 invalid return type is a deduction failure. */
12817 {
12819 {
12822 else
12824 }
12826 }
12827 /* And DR 657. */
12832 {
12833 /* Substitute the argument types. */
12838 }
12840 /* Construct a new type node and return it. */
12842 {
12847 }
12848 else
12849 {
12851 /* Don't pick up extra function qualifiers from the basetype. */
12854 {
12855 /* [temp.deduct]
12857 Type deduction may fail for any of the following
12858 reasons:
12860 -- Attempting to create "pointer to member of T" when T
12861 is not a class type. */
12864 r);
12866 }
12871 }
12878 }
12880 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
12881 ARGS into that specification, and return the substituted
12882 specification. If there is no specification, return NULL_TREE. */
12884 static tree
12886 tree args,
12887 tsubst_flags_t complain,
12888 tree in_decl,
12890 {
12891 tree specs;
12892 tree new_specs;
12897 {
12898 /* A noexcept-specifier. */
12903 {
12904 /* Defer instantiation of noexcept-specifiers to avoid
12905 excessive instantiations (c++/49107). */
12908 {
12909 /* We already partially instantiated this member template,
12910 so combine the new args with the old. */
12915 }
12916 else
12917 {
12920 }
12921 }
12922 else
12923 new_specs = tsubst_copy_and_build
12927 }
12929 {
12932 else
12934 {
12935 tree spec;
12940 {
12941 /* Expand the pack expansion type. */
12944 in_decl);
12950 else
12951 {
12952 /* We're substituting into a member template, so
12953 we got a TYPE_PACK_EXPANSION back. Add that
12954 expansion and move on. */
12958 expanded_specs,
12959 complain);
12962 }
12963 }
12966 {
12969 else
12974 complain);
12975 }
12978 }
12979 }
12981 }
12983 /* Take the tree structure T and replace template parameters used
12984 therein with the argument vector ARGS. IN_DECL is an associated
12985 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
12986 Issue error and warning messages under control of COMPLAIN. Note
12987 that we must be relatively non-tolerant of extensions here, in
12988 order to preserve conformance; if we allow substitutions that
12989 should not be allowed, we may allow argument deductions that should
12990 not succeed, and therefore report ambiguous overload situations
12991 where there are none. In theory, we could allow the substitution,
12992 but indicate that it should have failed, and allow our caller to
12993 make sure that the right thing happens, but we don't try to do this
12994 yet.
12996 This function is used for dealing with types, decls and the like;
12997 for expressions, use tsubst_expr or tsubst_copy. */
12999 tree
13001 {
13024 else
13029 /* Reuse typedefs. We need to do this to handle dependent attributes,
13030 such as attribute aligned. */
13033 {
13037 {
13038 /* DECL represents an alias template and we want to
13039 instantiate it. */
13043 }
13047 {
13051 }
13056 else
13057 /* The typedef is from a non-template context. */
13061 {
13063 r = cp_build_qualified_type_real
13067 }
13068 else
13069 {
13070 /* We don't have an instantiation yet, so drop the typedef. */
13075 }
13076 }
13092 {
13118 {
13124 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
13125 needed. */
13131 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
13132 with TREE_SIDE_EFFECTS that indicates this is not an integral
13133 constant expression. */
13136 {
13139 }
13142 }
13148 {
13154 /* Early in template argument deduction substitution, we don't
13155 want to reduce the level of 'auto', or it will be confused
13156 with a normal template parm in subsequent deduction. */
13168 {
13172 {
13173 /* See through ARGUMENT_PACK_SELECT arguments. */
13175 /* If the selected argument is an expansion E, that most
13176 likely means we were called from
13177 gen_elem_of_pack_expansion_instantiation during the
13178 substituting of pack an argument pack (which Ith
13179 element is a pack expansion, where I is
13180 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
13181 In this case, the Ith element resulting from this
13182 substituting is going to be a pack expansion, which
13183 pattern is the pattern of E. Let's return the
13184 pattern of E, and
13185 gen_elem_of_pack_expansion_instantiation will
13186 build the resulting pack expansion from it. */
13188 {
13189 /* Make sure we aren't throwing away arg info. */
13192 }
13193 }
13194 }
13199 {
13201 /* If ARG is an argument pack, we don't actually want to
13202 perform a substitution here, because substitutions
13203 for argument packs are only done
13204 element-by-element. We can get to this point when
13205 substituting the type of a non-type template
13206 parameter pack, when that type actually contains
13207 template parameter packs from an outer template, e.g.,
13209 template<typename... Types> struct A {
13210 template<Types... Values> struct B { };
13211 }; */
13215 {
13221 return cp_build_qualified_type_real
13223 }
13225 {
13226 /* We are processing a type constructed from a
13227 template template parameter. */
13238 /* Consider this code:
13240 template <template <class> class Template>
13241 struct Internal {
13242 template <class Arg> using Bind = Template<Arg>;
13243 };
13245 template <template <class> class Template, class Arg>
13246 using Instantiate = Template<Arg>; //#0
13248 template <template <class> class Template,
13249 class Argument>
13250 using Bind =
13251 Instantiate<Internal<Template>::template Bind,
13252 Argument>; //#1
13254 When #1 is parsed, the
13255 BOUND_TEMPLATE_TEMPLATE_PARM representing the
13256 parameter `Template' in #0 matches the
13257 UNBOUND_CLASS_TEMPLATE representing the argument
13258 `Internal<Template>::template Bind'; We then want
13259 to assemble the type `Bind<Argument>' that can't
13260 be fully created right now, because
13261 `Internal<Template>' not being complete, the Bind
13262 template cannot be looked up in that context. So
13263 we need to "store" `Bind<Argument>' for later
13264 when the context of Bind becomes complete. Let's
13265 store that in a TYPENAME_TYPE. */
13269 argvec),
13270 typename_type,
13271 complain);
13273 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
13274 are resolving nested-types in the signature of a
13275 member function templates. Otherwise ARG is a
13276 TEMPLATE_DECL and is the real template to be
13277 instantiated. */
13285 complain);
13286 return cp_build_qualified_type_real
13288 }
13291 else
13292 /* TEMPLATE_PARM_INDEX. */
13294 }
13297 /* This can happen during the attempted tsubst'ing in
13298 unify. This means that we don't yet have any information
13299 about the template parameter in question. */
13302 /* If we get here, we must have been looking at a parm for a
13303 more deeply nested template. Make a new version of this
13304 template parameter, but with a lower level. */
13306 {
13311 {
13313 r = cp_build_qualified_type_real
13317 }
13324 /* Break infinite recursion when substituting the constraints
13326 else
13327 {
13338 {
13339 /* Propagate constraints on placeholders. */
13344 {
13348 }
13349 }
13352 /* We have reduced the level of the template
13353 template parameter, but not the levels of its
13354 template parameters, so canonical_type_parameter
13355 will not be able to find the canonical template
13356 template parameter for this level. Thus, we
13357 require structural equality checking to compare
13358 TEMPLATE_TEMPLATE_PARMs. */
13362 else
13366 {
13368 /* We might need to substitute into the types of non-type
13369 template parameters. */
13381 }
13382 }
13391 }
13394 }
13397 {
13405 {
13409 }
13412 {
13416 }
13419 {
13423 }
13429 }
13432 /* We should never be tsubsting a binfo. */
13436 /* A vector of template arguments. */
13442 {
13446 /* [temp.deduct]
13448 Type deduction may fail for any of the following
13449 reasons:
13451 -- Attempting to create a pointer to reference type.
13452 -- Attempting to create a reference to a reference type or
13453 a reference to void.
13455 Core issue 106 says that creating a reference to a reference
13456 during instantiation is no longer a cause for failure. We
13457 only enforce this check in strict C++98 mode. */
13461 {
13464 /* We keep track of the last time we issued this error
13465 message to avoid spewing a ton of messages during a
13466 single bad template instantiation. */
13469 {
13474 else
13477 }
13480 }
13484 {
13486 {
13489 type);
13490 else
13492 type);
13493 }
13495 }
13497 {
13501 }
13503 /* In C++0x, during template argument substitution, when there is an
13504 attempt to create a reference to a reference type, reference
13505 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
13507 "If a template-argument for a template-parameter T names a type
13508 that is a reference to a type A, an attempt to create the type
13509 'lvalue reference to cv T' creates the type 'lvalue reference to
13510 A,' while an attempt to create the type type rvalue reference to
13511 cv T' creates the type T"
13512 */
13513 r = cp_build_reference_type
13516 else
13521 /* Will this ever be needed for TYPE_..._TO values? */
13525 }
13527 {
13530 {
13531 /* [temp.deduct]
13533 Type deduction may fail for any of the following
13534 reasons:
13536 -- Attempting to create "pointer to member of T" when T
13537 is not a class type. */
13541 }
13543 {
13547 }
13549 {
13553 }
13556 {
13557 /* The type of the implicit object parameter gets its
13558 cv-qualifiers from the FUNCTION_TYPE. */
13559 tree memptr;
13560 tree method_type
13565 complain);
13566 }
13567 else
13570 complain);
13571 }
13574 {
13575 tree fntype;
13576 tree specs;
13581 /* Substitute the exception specification. */
13589 }
13591 {
13596 /* As an optimization, we avoid regenerating the array type if
13597 it will obviously be the same as T. */
13601 /* These checks should match the ones in create_array_type_for_decl.
13603 [temp.deduct]
13605 The deduction may fail for any of the following reasons:
13607 -- Attempting to create an array with an element type that
13608 is void, a function type, or a reference type, or [DR337]
13609 an abstract class type. */
13615 {
13619 }
13627 {
13630 }
13633 }
13636 {
13648 {
13652 }
13654 {
13655 /* Normally, make_typename_type does not require that the CTX
13656 have complete type in order to allow things like:
13658 template <class T> struct S { typename S<T>::X Y; };
13660 But, such constructs have already been resolved by this
13661 point, so here CTX really should have complete type, unless
13662 it's a partial instantiation. */
13665 {
13669 }
13670 }
13677 {
13680 }
13683 {
13685 {
13689 else
13691 }
13693 {
13697 else
13699 }
13700 }
13702 return cp_build_qualified_type_real
13704 }
13707 {
13719 }
13722 {
13723 tree type;
13739 complain);
13740 }
13743 {
13744 tree type;
13755 {
13757 {
13761 }
13764 }
13774 else
13775 {
13779 /* In a template ~id could be either a complement expression
13780 or an unqualified-id naming a destructor; if instantiating
13781 it produces an expression, it's not an id-expression or
13782 member access. */
13785 }
13790 }
13793 {
13797 }
13801 {
13802 tree r;
13805 {
13807 /* Set the already-substituted type. */
13809 }
13810 else
13818 }
13833 /* We should use one of the expression tsubsts for these codes. */
13839 }
13840 }
13842 /* Like tsubst_expr for a BASELINK. OBJECT_TYPE, if non-NULL, is the
13843 type of the expression on the left-hand side of the "." or "->"
13844 operator. */
13846 static tree
13849 {
13850 tree name;
13851 tree qualifying_scope;
13852 tree fns;
13853 tree optype;
13858 /* A baselink indicates a function from a base class. Both the
13859 BASELINK_ACCESS_BINFO and the base class referenced may
13860 indicate bases of the template class, rather than the
13861 instantiated class. In addition, lookups that were not
13862 ambiguous before may be ambiguous now. Therefore, we perform
13863 the lookup again. */
13870 {
13877 }
13883 {
13885 {
13889 }
13891 }
13893 /* If lookup found a single function, mark it as used at this
13894 point. (If it lookup found multiple functions the one selected
13895 later by overload resolution will be marked as used at that
13896 point.) */
13903 /* Add back the template arguments, if present. */
13907 unknown_type_node,
13909 template_args);
13910 /* Update the conversion operator type. */
13918 {
13920 qualifying_scope,
13921 object_type);
13923 /* We need to call adjust_result_of_qualified_name_lookup in case the
13924 destructor names a base class, but we unset BASELINK_QUALIFIED_P
13925 so that we still get virtual function binding. */
13927 }
13929 }
13931 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
13932 true if the qualified-id will be a postfix-expression in-and-of
13933 itself; false if more of the postfix-expression follows the
13934 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
13935 of "&". */
13937 static tree
13941 {
13942 tree expr;
13943 tree scope;
13944 tree name;
13946 tree template_args;
13951 /* Figure out what name to look up. */
13954 {
13964 }
13965 else
13966 {
13969 }
13971 /* Substitute into the qualifying scope. When there are no ARGS, we
13972 are just trying to simplify a non-dependent expression. In that
13973 case the qualifying scope may be dependent, and, in any case,
13974 substituting will not help. */
13977 {
13980 }
13981 else
13985 {
13992 }
13995 {
13997 {
13998 /* A BIT_NOT_EXPR is used to represent a destructor. */
14000 {
14004 }
14005 else
14008 }
14009 else
14013 {
14015 {
14019 }
14021 }
14022 }
14025 {
14027 scope);
14028 /* Remember that there was a reference to this entity. */
14031 }
14034 {
14040 }
14043 {
14046 complain);
14047 else
14049 }
14055 {
14056 expr = (adjust_result_of_qualified_name_lookup
14058 expr = (finish_qualified_id_expr
14062 }
14064 /* Expressions do not generally have reference type. */
14066 /* However, if we're about to form a pointer-to-member, we just
14067 want the referenced member referenced. */
14075 }
14077 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
14078 initializer, DECL is the substituted VAR_DECL. Other arguments are as
14079 for tsubst. */
14081 static tree
14084 {
14091 {
14092 /* If we had an initializer but it
14093 instantiated to nothing,
14094 value-initialize the object. This will
14095 only occur when the initializer was a
14096 pack expansion where the parameter packs
14097 used in that expansion were of length
14098 zero. */
14100 complain);
14103 }
14106 }
14108 /* Like tsubst, but deals with expressions. This function just replaces
14109 template parms; to finish processing the resultant expression, use
14110 tsubst_copy_and_build or tsubst_expr. */
14112 static tree
14114 {
14116 tree r;
14124 {
14129 {
14130 /* We get here for a use of 'this' in an NSDMI as part of a
14131 constructor call or as part of an aggregate initialization. */
14133 && ((current_function_decl
14135 || (current_class_ref
14139 /* This can happen for a parameter name used later in a function
14140 declaration (such as in a late-specified return type). Just
14141 make a dummy decl, since it's only used for its type. */
14144 /* Give it the template pattern as its context; its true context
14145 hasn't been instantiated yet and this is good enough for
14146 mangling. */
14148 }
14157 {
14158 tree enum_type;
14159 tree v;
14163 /* There is no need to substitute into namespace-scope
14164 enumerators. */
14167 /* If ARGS is NULL, then T is known to be non-dependent. */
14171 /* Unfortunately, we cannot just call lookup_name here.
14172 Consider:
14174 template <int I> int f() {
14175 enum E { a = I };
14176 struct S { void g() { E e = a; } };
14177 };
14179 When we instantiate f<7>::S::g(), say, lookup_name is not
14180 clever enough to find f<7>::a. */
14181 enum_type
14191 /* We didn't find the name. That should never happen; if
14192 name-lookup found it during preliminary parsing, we
14193 should find it again here during instantiation. */
14195 }
14200 {
14201 /* Check for a local specialization set up by
14202 tsubst_pack_expansion. */
14204 {
14208 }
14210 /* When retrieving a capture pack from a generic lambda, remove the
14211 lambda call op's own template argument list from ARGS. Only the
14212 template arguments active for the closure type should be used to
14213 retrieve the pack specialization. */
14219 /* Otherwise return the full NONTYPE_ARGUMENT_PACK that
14220 tsubst_decl put in the hash table. */
14222 }
14225 {
14226 tree ctx;
14231 {
14234 {
14238 }
14240 }
14241 }
14251 {
14254 {
14255 /* First try name lookup to find the instantiation. */
14258 {
14259 /* Make sure that the one we found is the one we want. */
14265 }
14269 else
14270 {
14271 /* This can happen for a variable used in a
14272 late-specified return type of a local lambda, or for a
14273 local static or constant. Building a new VAR_DECL
14274 should be OK in all those cases. */
14277 {
14278 /* We can't call cp_finish_decl, so handle the
14279 initializer by hand. */
14290 }
14297 }
14298 /* Remember this for subsequent uses. */
14301 }
14302 }
14303 else
14313 /* An OVERLOAD will always be a non-dependent overload set; an
14314 overload set from function scope will just be represented with an
14315 IDENTIFIER_NODE, and from class scope with a BASELINK. */
14331 {
14332 /* Template template argument like the following example need
14333 special treatment:
14335 template <template <class> class TT> struct C {};
14336 template <class T> struct D {
14337 template <class U> struct E {};
14338 C<E> c; // #1
14339 };
14340 D<int> d; // #2
14342 We are processing the template argument `E' in #1 for
14343 the template instantiation #2. Originally, `E' is a
14344 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
14345 have to substitute this with one having context `D<int>'. */
14349 }
14350 else
14351 /* Ordinary template template argument. */
14362 {
14366 }
14371 {
14380 /* We only want to compute the number of arguments. */
14383 else
14390 {
14392 /* Set TREE_USED for the benefit of -Wunused. */
14396 }
14404 {
14409 else
14415 else
14418 }
14419 else
14421 }
14423 {
14431 }
14432 /* Fall through */
14448 {
14452 }
14455 {
14456 tree object;
14457 tree name;
14462 {
14466 }
14469 {
14479 }
14484 in_decl);
14485 else
14488 }
14526 {
14530 }
14533 {
14538 }
14541 {
14545 }
14548 {
14556 }
14562 {
14569 }
14572 {
14579 }
14582 {
14589 }
14592 {
14593 /* Substituted template arguments */
14602 }
14605 {
14625 }
14650 /* Fall through. */
14653 {
14656 }
14657 else
14661 /* This is handled by tsubst_copy_and_build. */
14665 {
14669 }
14672 /* We shouldn't have built any of these during initial template
14673 generation. Instead, they should be built during instantiation
14674 in response to the saved STMT_IS_FULL_EXPR_P setting. */
14678 {
14688 }
14706 {
14707 /* Instantiate any typedefs in the type. */
14712 }
14715 /* These can sometimes show up in a partial instantiation, but never
14716 involve template parms. */
14730 /* We shouldn't get here, but keep going if !flag_checking. */
14734 }
14735 }
14737 /* Helper function for tsubst_omp_clauses, used for instantiation of
14738 OMP_CLAUSE_DECL of clauses. */
14740 static tree
14742 tree in_decl)
14743 {
14747 /* Handle an OpenMP array section represented as a TREE_LIST (or
14748 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
14749 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
14750 TREE_LIST. We can handle it exactly the same as an array section
14751 (purpose, value, and a chain), even though the nomenclature
14752 (low_bound, length, etc) is different. */
14754 {
14755 tree low_bound
14761 in_decl);
14770 }
14773 /* Undo convert_from_reference tsubst_expr could have called. */
14779 }
14781 /* Like tsubst_copy, but specifically for OpenMP clauses. */
14783 static tree
14786 {
14791 {
14797 {
14800 {
14806 }
14807 /* FALLTHRU */
14822 in_decl);
14853 {
14856 {
14863 }
14864 else
14866 }
14869 in_decl);
14875 in_decl);
14883 in_decl);
14885 {
14888 }
14893 else
14896 in_decl,
14919 {
14923 loc;
14925 {
14928 }
14929 }
14933 }
14936 {
14946 /* tsubst_expr on SCOPE_REF results in returning
14947 finish_non_static_data_member result. Undo that here. */
14951 {
14956 {
14960 CASE_CONVERT:
14969 /* FALLTHRU */
14973 }
14974 }
14980 {
14983 {
14987 }
14988 }
14992 }
14993 }
14997 {
15002 {
15005 }
15006 }
15008 }
15010 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
15012 static tree
15014 tree in_decl)
15015 {
15016 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
15036 {
15039 else
15040 {
15044 }
15045 }
15050 #undef RECUR
15051 }
15053 /* Used to temporarily communicate the list of #pragma omp parallel
15054 clauses to #pragma omp for instantiation if they are combined
15055 together. */
15059 /* Substitute one OMP_FOR iterator. */
15061 static void
15066 {
15067 #define RECUR(NODE) \
15068 tsubst_expr ((NODE), args, complain, in_decl, \
15069 integral_constant_expression_p)
15076 {
15079 }
15085 {
15086 /* We need to jump through some hoops to handle declarations in the
15087 init-statement, since we might need to handle auto deduction,
15088 but we need to keep control of initialization. */
15092 }
15093 else
15094 {
15096 {
15099 {
15103 {
15107 CASE_CONVERT:
15115 {
15118 }
15119 /* FALLTHRU */
15123 }
15124 }
15125 }
15126 else
15128 }
15139 {
15141 {
15142 /* Declare the variable, but don't let that initialize it. */
15147 }
15152 {
15157 }
15158 else
15165 }
15168 {
15169 /* Declare and initialize the variable. */
15172 }
15174 {
15178 {
15180 {
15186 {
15189 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
15194 }
15197 {
15199 decl);
15201 }
15204 {
15206 decl);
15208 }
15209 else
15211 }
15214 }
15216 {
15221 {
15224 }
15225 }
15226 }
15229 {
15233 }
15234 else
15238 {
15249 {
15257 }
15258 else
15264 {
15270 }
15274 {
15282 }
15283 else
15289 }
15295 #undef RECUR
15296 }
15298 /* Helper function of tsubst_expr, find OMP_TEAMS inside
15299 of OMP_TARGET's body. */
15301 static tree
15303 {
15306 {
15315 }
15317 }
15319 /* Helper function for tsubst_expr. For decomposition declaration
15320 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
15321 also the corresponding decls representing the identifiers
15322 of the decomposition declaration. Return DECL if successful
15323 or error_mark_node otherwise, set *FIRST to the first decl
15324 in the list chained through DECL_CHAIN and *CNT to the number
15325 of such decls. */
15327 static tree
15331 {
15336 decl2
15341 {
15357 {
15360 }
15361 else
15363 }
15366 }
15368 /* Like tsubst_copy for expressions, etc. but also does semantic
15369 processing. */
15371 tree
15374 {
15375 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
15376 #define RECUR(NODE) \
15377 tsubst_expr ((NODE), args, complain, in_decl, \
15378 integral_constant_expression_p)
15381 tree r;
15382 location_t loc;
15394 {
15396 {
15397 tree_stmt_iterator i;
15401 }
15416 else
15425 {
15427 tree init;
15433 {
15443 else
15445 }
15447 {
15448 /* Don't build up decls for a variadic capture proxy, we'll
15449 instantiate the elements directly as needed. */
15451 }
15452 else
15453 {
15457 {
15458 /* By marking the declaration as instantiated, we avoid
15459 trying to instantiate it. Since instantiate_decl can't
15460 handle local variables, and since we've already done
15461 all that needs to be done, that's the right thing to
15462 do. */
15467 /* Anonymous aggregates are a special case. */
15470 {
15473 {
15477 }
15479 }
15485 {
15490 }
15491 else
15492 {
15497 {
15498 /* For __PRETTY_FUNCTION__ we have to adjust the
15499 initializer. */
15503 }
15504 else
15508 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
15512 {
15514 tree first;
15520 }
15521 }
15522 }
15523 }
15526 }
15541 {
15549 {
15551 tree first;
15556 }
15557 else
15562 }
15588 else
15589 {
15596 }
15602 {
15611 }
15619 else
15627 else
15648 {
15655 }
15659 {
15661 tree label;
15668 }
15674 /* Computed goto's must be tsubst'd into. On the other hand,
15675 non-computed gotos must not be; the identifier in question
15676 will have no binding. */
15678 else
15684 {
15700 }
15705 {
15710 }
15711 else
15712 {
15717 else
15724 else
15730 else
15732 }
15736 {
15740 {
15742 /* Prevent instantiate_decl from trying to instantiate
15743 this variable. We've already done all that needs to be
15744 done. */
15747 }
15752 }
15758 {
15759 /* Local classes are not independent templates; they are
15760 instantiated along with their containing function. And this
15761 way we don't have to deal with pushing out of one local class
15762 to instantiate a member of another local class. */
15763 tree fn;
15764 /* Closures are handled by the LAMBDA_EXPR. */
15770 }
15774 {
15775 tree condition;
15778 condition =
15780 args,
15789 }
15795 in_decl);
15832 {
15847 in_decl);
15849 {
15856 }
15868 integral_constant_expression_p);
15879 else
15880 {
15888 }
15892 }
15897 /* FALLTHRU */
15904 in_decl);
15921 in_decl);
15932 {
15935 {
15936 /* For combined target teams, ensure the num_teams and
15937 thread_limit clause expressions are evaluated on the host,
15938 before entering the target construct. */
15939 tree c;
15945 {
15954 OMP_CLAUSE_FIRSTPRIVATE);
15958 }
15959 }
15960 }
16020 {
16025 {
16028 }
16034 }
16035 else
16036 {
16043 {
16046 }
16049 {
16054 {
16057 }
16063 }
16064 else
16065 {
16069 }
16072 }
16076 {
16082 {
16086 {
16091 }
16095 }
16096 else
16097 {
16102 }
16103 }
16107 {
16111 }
16131 /* If the first operand was a statement, we're done with it. */
16135 complain));
16147 integral_constant_expression_p));
16148 }
16151 out:
16154 #undef RECUR
16155 #undef RETURN
16156 }
16158 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
16159 function. For description of the body see comment above
16160 cp_parser_omp_declare_reduction_exprs. */
16162 static void
16164 {
16170 tree_stmt_iterator tsi;
16181 {
16200 }
16202 {
16222 }
16223 }
16225 /* T is a postfix-expression that is not being used in a function
16226 call. Return the substituted version of T. */
16228 static tree
16230 tsubst_flags_t complain,
16231 tree in_decl)
16232 {
16236 else
16242 }
16244 /* Like tsubst but deals with expressions and performs semantic
16245 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
16247 tree
16249 tree args,
16250 tsubst_flags_t complain,
16251 tree in_decl,
16254 {
16255 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
16256 #define RECUR(NODE) \
16257 tsubst_copy_and_build (NODE, args, complain, in_decl, \
16259 integral_constant_expression_p)
16262 location_t loc;
16271 /* N3276 decltype magic only applies to calls at the top level or on the
16272 right side of a comma. */
16277 {
16280 /* Fall through. */
16282 {
16283 tree decl;
16284 cp_id_kind idk;
16289 {
16292 }
16294 /* Look up the name. */
16297 /* By convention, expressions use ERROR_MARK_NODE to indicate
16298 failure, not NULL_TREE. */
16304 integral_constant_expression_p,
16312 input_location);
16316 {
16320 }
16322 }
16325 {
16326 tree object;
16339 {
16342 }
16343 else
16350 else
16352 }
16355 {
16359 {
16360 /* A type conversion to reference type will be enclosed in
16361 such an indirect ref, but the substitution of the cast
16362 will have also added such an indirect ref. */
16365 }
16366 else
16374 }
16377 {
16381 }
16384 {
16391 flags));
16392 }
16395 {
16399 }
16406 {
16407 tree type;
16413 {
16418 }
16424 {
16442 }
16445 }
16479 else
16481 in_decl);
16516 {
16523 tree r = build_x_binary_op
16525 op0,
16527 ? ERROR_MARK
16529 op1,
16531 ? ERROR_MARK
16539 }
16542 {
16546 }
16559 {
16568 }
16573 /* Fall through */
16576 {
16577 tree r;
16583 {
16584 /* When there are no ARGS, we are trying to evaluate a
16585 non-dependent expression from the parser. Trying to do
16586 the substitutions may not work. */
16589 }
16590 else
16591 {
16596 else
16599 /*integral_constant_expression_p=*/
16603 }
16607 else
16611 {
16613 {
16615 {
16619 }
16620 else
16624 }
16626 }
16628 }
16631 {
16641 }
16657 {
16661 tree r = build_x_modify_expr
16664 /* TREE_NO_WARNING must be set if either the expression was
16665 parenthesized or it uses an operator such as >>= rather
16666 than plain assignment. In the former case, it was already
16667 set and must be copied. In the latter case,
16668 build_x_modify_expr sets it and it must not be reset
16669 here. */
16674 }
16679 /* Remember that there was a reference to this entity. */
16686 {
16691 tree ret;
16695 else
16696 {
16700 }
16702 /* If there was an initializer in the original tree, but it
16703 instantiated to an empty list, then we should pass a
16704 non-NULL empty vector to tell build_new that it was an
16705 empty initializer() rather than no initializer. This can
16706 only happen when the initializer is a pack expansion whose
16707 parameter packs are of length zero. */
16710 else
16711 {
16715 else
16716 {
16719 }
16720 }
16726 complain);
16734 }
16737 {
16743 complain));
16744 }
16747 {
16751 integral_constant_expression_p);
16753 op0,
16756 }
16759 {
16760 tree function;
16765 tree ret;
16768 /* Internal function with no arguments. */
16772 /* When we parsed the expression, we determined whether or
16773 not Koenig lookup should be performed. */
16776 {
16779 }
16781 {
16786 }
16788 {
16789 /* Do nothing; calling tsubst_copy_and_build on an identifier
16790 would incorrectly perform unqualified lookup again.
16792 Note that we can also have an IDENTIFIER_NODE if the earlier
16793 unqualified lookup found a member function; in that case
16794 koenig_p will be false and we do want to do the lookup
16795 again to find the instantiated member function.
16797 FIXME but doing that causes c++/15272, so we need to stop
16798 using IDENTIFIER_NODE in that situation. */
16800 }
16801 else
16802 {
16804 {
16810 }
16811 else
16816 /* Avoid error about taking the address of a constructor. */
16820 in_decl,
16822 integral_constant_expression_p);
16826 }
16831 {
16836 else
16837 {
16838 /* Expand the pack expansion and push each entry onto
16839 CALL_ARGS. */
16842 {
16847 {
16852 }
16853 }
16854 else
16855 {
16856 /* A partial substitution. Add one entry. */
16858 }
16859 }
16860 }
16862 /* We do not perform argument-dependent lookup if normal
16863 lookup finds a non-function, in accordance with the
16864 expected resolution of DR 218. */
16867 /* If lookup found a member function, the Koenig lookup is
16868 not appropriate, even if an unqualified-name was used
16869 to denote the function. */
16872 /* Only do this when substitution turns a dependent call
16873 into a non-dependent call. */
16881 {
16883 {
16884 /* For backwards compatibility and good diagnostics, try
16885 the unqualified lookup again if we aren't in SFINAE
16886 context. */
16887 tree unq = (tsubst_copy_and_build
16889 integral_constant_expression_p));
16891 {
16894 }
16897 {
16906 "%qD was not declared in this scope, "
16907 "and no declarations were found by "
16908 "argument-dependent lookup at the point "
16910 {
16914 {
16916 input_location);
16918 "declarations in dependent base %qT are "
16924 else
16928 }
16929 else
16931 "%qD declared here, later in the "
16933 }
16935 }
16936 }
16938 {
16943 }
16944 }
16946 /* Remember that there was a reference to this entity. */
16950 {
16953 }
16955 /* Put back tf_decltype for the actual call. */
16960 {
16964 {
16966 "wrong number of arguments to "
16969 }
16970 else
16972 input_location),
16977 /* Unsupported internal function with arguments. */
16979 }
16982 complain);
16984 {
16999 complain);
17000 else
17001 ret = (build_new_method_call
17006 complain));
17007 }
17008 else
17011 koenig_p,
17012 complain);
17017 {
17023 {
17029 {
17031 /* The thunk location is not interesting. */
17033 }
17034 }
17035 }
17038 }
17041 {
17047 {
17049 {
17054 }
17055 else
17056 {
17061 }
17063 }
17064 else
17065 {
17068 }
17072 }
17075 {
17080 input_location));
17081 }
17084 {
17092 {
17093 /* We have pack expansions, so expand those and
17094 create a new list out of it. */
17097 tree chain;
17100 /* Expand the argument expressions. */
17108 /* Build the rest of the list. */
17113 /* Determine the number of arguments. */
17115 {
17118 }
17121 else
17122 {
17123 /* Since we only performed a partial substitution into
17124 the argument pack, we only RETURN (a single list
17125 node. */
17132 }
17134 /* Convert the argument vectors into a TREE_LIST */
17137 {
17138 /* Grab the Ith values. */
17139 i--;
17142 value
17146 /* Build the list (backwards). */
17148 }
17151 }
17167 }
17170 {
17171 tree object;
17172 tree object_type;
17173 tree member;
17174 tree r;
17178 /* Remember that there was a reference to this entity. */
17189 else
17197 {
17199 {
17204 {
17207 }
17209 {
17214 }
17215 }
17216 }
17219 {
17220 /* Lookup the template functions now that we know what the
17221 scope is. */
17229 {
17232 args);
17233 member = (adjust_result_of_qualified_name_lookup
17235 object_type));
17236 }
17237 else
17238 {
17240 input_location);
17242 }
17243 }
17247 {
17249 {
17253 else
17256 }
17258 }
17260 {
17265 }
17269 complain);
17273 }
17280 {
17288 tree r;
17293 /* digest_init will do the wrong thing if we let it. */
17297 /* We do not want to process the index of aggregate
17298 initializers as they are identifier nodes which will be
17299 looked up by digest_init. */
17305 {
17307 /* An identifier index is looked up in the type
17308 being initialized, not the current scope. */
17313 {
17314 /* Substitute into the pack expansion. */
17316 in_decl);
17320 ;
17322 /* Just move the argument into place. */
17324 else
17325 {
17326 /* Update the length of the final CONSTRUCTOR
17327 arguments vector, and note that we will need to
17328 copy.*/
17331 }
17332 }
17333 else
17335 }
17338 {
17343 {
17345 {
17350 }
17351 else
17353 }
17354 }
17364 }
17367 {
17370 {
17373 }
17374 else
17375 {
17378 }
17379 }
17385 {
17386 /* We don't build decls for an instantiation of a
17387 variadic capture proxy, we instantiate the elements
17388 when needed. */
17391 }
17392 /* Fall through */
17395 {
17397 /* ??? We're doing a subset of finish_id_expression here. */
17399 && !processing_template_decl
17400 && !cp_unevaluated_operand
17403 {
17405 /* Replace an evaluated use of the thread_local variable with
17406 a call to its wrapper. */
17408 }
17410 {
17414 }
17417 /* If the original type was a reference, we'll be wrapped in
17418 the appropriate INDIRECT_REF. */
17421 }
17424 {
17428 }
17439 {
17450 }
17453 {
17459 integral_constant_expression_p);
17463 /* If the resulting list of expression statement is empty,
17464 fold it further into void_node. */
17469 }
17472 {
17490 /* For a function or variable scope, we want to use tsubst so that we
17491 don't complain about referring to an auto before deduction. */
17494 {
17495 /* Look up the parameter we want directly, as tsubst_copy
17496 doesn't do what we need. */
17502 /* FIXME Work around the parm not having DECL_CONTEXT set. */
17505 }
17507 /* For a field, use tsubst_copy so that we look up the existing field
17508 rather than build a new one. */
17510 else
17517 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
17519 /* Now that we know visibility, instantiate the type so we have a
17520 declaration of the op() for later calls to lambda_function. */
17531 }
17534 /* We can get here for a constant initializer of non-dependent type.
17535 FIXME stop folding in cp_parser_initializer_clause. */
17536 {
17538 complain);
17540 }
17544 integral_constant_expression_p));
17550 {
17555 complain));
17556 }
17562 /* Handle Objective-C++ constructs, if appropriate. */
17563 {
17564 tree subst
17569 }
17571 }
17573 #undef RECUR
17574 #undef RETURN
17575 out:
17578 }
17580 /* Verify that the instantiated ARGS are valid. For type arguments,
17581 make sure that the type's linkage is ok. For non-type arguments,
17582 make sure they are constants if they are integral or enumerations.
17583 Emit an error under control of COMPLAIN, and return TRUE on error. */
17585 static bool
17587 {
17591 {
17601 }
17603 {
17604 /* [basic.link]: A name with no linkage (notably, the name
17605 of a class or enumeration declared in a local scope)
17606 shall not be used to declare an entity with linkage.
17607 This implies that names with no linkage cannot be used as
17608 template arguments
17610 DR 757 relaxes this restriction for C++0x. */
17615 {
17616 /* DR 488 makes use of a type with no linkage cause
17617 type deduction to fail. */
17619 {
17622 else
17625 }
17627 }
17628 /* In order to avoid all sorts of complications, we do not
17629 allow variably-modified types as template arguments. */
17631 {
17635 }
17636 }
17637 /* Class template and alias template arguments should be OK. */
17639 ;
17640 /* A non-type argument of integral or enumerated type must be a
17641 constant. */
17646 {
17650 }
17652 }
17654 static bool
17656 {
17661 {
17664 }
17668 }
17670 /* We're out of SFINAE context now, so generate diagnostics for the access
17671 errors we saw earlier when instantiating D from TMPL and ARGS. */
17673 static void
17675 {
17687 }
17689 /* Instantiate the indicated variable, function, or alias template TMPL with
17690 the template arguments in TARG_PTR. */
17692 static tree
17694 {
17696 tree fndecl;
17697 tree gen_tmpl;
17698 tree spec;
17706 /* If this function is a clone, handle it specially. */
17708 {
17709 tree spec;
17710 tree clone;
17712 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
17713 DECL_CLONED_FUNCTION. */
17719 /* Look for the clone. */
17723 /* We should always have found the clone by now. */
17726 }
17731 /* Check to see if we already have this specialization. */
17735 /* targ_ptr only has the innermost template args, so add the outer ones
17736 from tmpl, which could be either a partial instantiation or gen_tmpl (in
17737 the case of a non-dependent call within a template definition). */
17738 targ_ptr = (add_outermost_template_args
17740 targ_ptr));
17742 /* It would be nice to avoid hashing here and then again in tsubst_decl,
17743 but it doesn't seem to be on the hot path. */
17752 {
17754 {
17758 }
17760 }
17763 complain))
17766 /* We are building a FUNCTION_DECL, during which the access of its
17767 parameters and return types have to be checked. However this
17768 FUNCTION_DECL which is the desired context for access checking
17769 is not built yet. We solve this chicken-and-egg problem by
17770 deferring all checks until we have the FUNCTION_DECL. */
17773 /* Instantiation of the function happens in the context of the function
17774 template, not the context of the overload resolution we're doing. */
17776 /* If there are dependent arguments, e.g. because we're doing partial
17777 ordering, make sure processing_template_decl stays set. */
17781 {
17785 }
17791 {
17792 /* We need to determine if we're using a partial or explicit
17793 specialization now, because the type of the variable could be
17794 different. */
17800 {
17805 }
17806 }
17808 /* Substitute template parameters to obtain the specialization. */
17816 {
17819 }
17821 /* The DECL_TI_TEMPLATE should always be the immediate parent
17822 template, not the most general template. */
17826 /* Now we know the specialization, compute access previously
17827 deferred. Do no access control for inheriting constructors,
17828 as we already checked access for the inherited constructor. */
17831 {
17836 }
17839 /* If we've just instantiated the main entry point for a function,
17840 instantiate all the alternate entry points as well. We do this
17841 by cloning the instantiation of the main entry point, not by
17842 instantiating the template clones. */
17847 {
17849 {
17850 /* Remember to reinstantiate when we're out of SFINAE so the user
17851 can see the errors. */
17853 }
17855 }
17857 }
17859 /* Wrapper for instantiate_template_1. */
17861 tree
17863 {
17864 tree ret;
17869 }
17871 /* Instantiate the alias template TMPL with ARGS. Also push a template
17872 instantiation level, which instantiate_template doesn't do because
17873 functions and variables have sufficient context established by the
17874 callers. */
17876 static tree
17878 {
17885 {
17888 }
17890 args =
17898 /* We can't free this if a pending_template entry or last_error_tinst_level
17899 is pointing at it. */
17905 }
17907 /* PARM is a template parameter pack for FN. Returns true iff
17908 PARM is used in a deducible way in the argument list of FN. */
17910 static bool
17912 {
17915 {
17917 tree packs;
17923 {
17924 /* The template parameter pack is used in a function parameter
17925 pack. If this is the end of the parameter list, the
17926 template parameter pack is deducible. */
17929 else
17930 /* Otherwise, not. Well, it could be deduced from
17931 a non-pack parameter, but doing so would end up with
17932 a deduction mismatch, so don't bother. */
17934 }
17935 }
17936 /* The template parameter pack isn't used in any function parameter
17937 packs, but it might be used deeper, e.g. tuple<Args...>. */
17939 }
17941 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
17942 NARGS elements of the arguments that are being used when calling
17943 it. TARGS is a vector into which the deduced template arguments
17944 are placed.
17946 Returns either a FUNCTION_DECL for the matching specialization of FN or
17947 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
17948 true, diagnostics will be printed to explain why it failed.
17950 If FN is a conversion operator, or we are trying to produce a specific
17951 specialization, RETURN_TYPE is the return type desired.
17953 The EXPLICIT_TARGS are explicit template arguments provided via a
17954 template-id.
17956 The parameter STRICT is one of:
17958 DEDUCE_CALL:
17959 We are deducing arguments for a function call, as in
17960 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
17961 deducing arguments for a call to the result of a conversion
17962 function template, as in [over.call.object].
17964 DEDUCE_CONV:
17965 We are deducing arguments for a conversion function, as in
17966 [temp.deduct.conv].
17968 DEDUCE_EXACT:
17969 We are deducing arguments when doing an explicit instantiation
17970 as in [temp.explicit], when determining an explicit specialization
17971 as in [temp.expl.spec], or when taking the address of a function
17972 template, as in [temp.deduct.funcaddr]. */
17974 tree
17976 tree explicit_targs,
17977 tree targs,
17980 tree return_type,
17981 unification_kind_t strict,
17985 {
17986 tree parms;
17987 tree fntype;
18000 tree tinst;
18006 full_targs = (add_outermost_template_args
18008 targs));
18013 /* In C++0x, it's possible to have a function template whose type depends
18014 on itself recursively. This is most obvious with decltype, but can also
18015 occur with enumeration scope (c++/48969). So we need to catch infinite
18016 recursion and reject the substitution at deduction time; this function
18017 will return error_mark_node for any repeated substitution.
18019 This also catches excessive recursion such as when f<N> depends on
18020 f<N-1> across all integers, and returns error_mark_node for all the
18021 substitutions back up to the initial one.
18023 This is, of course, not reentrant. */
18033 {
18034 /* [temp.deduct]
18036 The specified template arguments must match the template
18037 parameters in kind (i.e., type, nontype, template), and there
18038 must not be more arguments than there are parameters;
18039 otherwise type deduction fails.
18041 Nontype arguments must match the types of the corresponding
18042 nontype template parameters, or must be convertible to the
18043 types of the corresponding nontype parameters as specified in
18044 _temp.arg.nontype_, otherwise type deduction fails.
18046 All references in the function type of the function template
18047 to the corresponding template parameters are replaced by the
18048 specified template argument values. If a substitution in a
18049 template parameter or in the function type of the function
18050 template results in an invalid type, type deduction fails. */
18061 explicit_targs);
18063 /* Adjust any explicit template arguments before entering the
18064 substitution context. */
18065 explicit_targs
18067 complain,
18073 /* Substitute the explicit args into the function type. This is
18074 necessary so that, for instance, explicitly declared function
18075 arguments can match null pointed constants. If we were given
18076 an incomplete set of explicit args, we must not do semantic
18077 processing during substitution as we could create partial
18078 instantiations. */
18080 {
18085 /* Dig out the actual parm. */
18088 {
18091 }
18093 {
18096 }
18099 /* No explicit argument for this template parameter. */
18103 {
18104 /* Mark the argument pack as "incomplete". We could
18105 still deduce more arguments during unification.
18106 We remove this mark in type_unification_real. */
18108 {
18112 }
18114 /* We have some incomplete argument packs. */
18116 }
18117 }
18121 {
18124 }
18127 /* Ignore any access checks; we'll see them again in
18128 instantiate_template and they might have the wrong
18129 access path at this point. */
18141 /* Place the explicitly specified arguments in TARGS. */
18145 }
18147 /* Never do unification on the 'this' parameter. */
18151 {
18152 /* We're deducing for a call to the result of a template conversion
18153 function. The parms we really want are in return_type. */
18157 }
18159 {
18168 }
18170 /* We allow incomplete unification without an error message here
18171 because the standard doesn't seem to explicitly prohibit it. Our
18172 callers must be ready to deal with unification failures in any
18173 event. */
18176 /* If we aren't explaining yet, push tinst context so we can see where
18177 any errors (e.g. from class instantiations triggered by instantiation
18178 of default template arguments) come from. If we are explaining, this
18179 context is redundant. */
18181 {
18184 }
18186 /* type_unification_real will pass back any access checks from default
18187 template argument substitution. */
18199 /* Now that we have bindings for all of the template arguments,
18200 ensure that the arguments deduced for the template template
18201 parameters have compatible template parameter lists. We cannot
18202 check this property before we have deduced all template
18203 arguments, because the template parameter types of a template
18204 template parameter might depend on prior template parameters
18205 deduced after the template template parameter. The following
18206 ill-formed example illustrates this issue:
18208 template<typename T, template<T> class C> void f(C<5>, T);
18210 template<int N> struct X {};
18212 void g() {
18213 f(X<5>(), 5l); // error: template argument deduction fails
18214 }
18216 The template parameter list of 'C' depends on the template type
18217 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
18218 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
18219 time that we deduce 'C'. */
18222 {
18225 }
18227 /* All is well so far. Now, check:
18229 [temp.deduct]
18231 When all template arguments have been deduced, all uses of
18232 template parameters in nondeduced contexts are replaced with
18233 the corresponding deduced argument values. If the
18234 substitution results in an invalid type, as described above,
18235 type deduction fails. */
18238 {
18241 }
18243 /* Also collect access checks from the instantiation. */
18256 /* Now perform any access checks encountered during substitution. */
18263 /* If we're looking for an exact match, check that what we got
18264 is indeed an exact match. It might not be if some template
18265 parameters are used in non-deduced contexts. But don't check
18266 for an exact match if we have dependent template arguments;
18267 in that case we're doing partial ordering, and we already know
18268 that we have two candidates that will provide the actual type. */
18270 {
18274 tree sarg
18280 {
18284 }
18285 }
18287 /* After doing deduction with the inherited constructor, actually return an
18288 instantiation of the inheriting constructor. */
18294 fail:
18297 {
18299 /* Reset once we're all the way out. */
18301 }
18303 /* We can't free this if a pending_template entry or last_error_tinst_level
18304 is pointing at it. */
18310 }
18312 /* Adjust types before performing type deduction, as described in
18313 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
18314 sections are symmetric. PARM is the type of a function parameter
18315 or the return type of the conversion function. ARG is the type of
18316 the argument passed to the call, or the type of the value
18317 initialized with the result of the conversion function.
18318 ARG_EXPR is the original argument expression, which may be null. */
18320 static int
18324 tree arg_expr)
18325 {
18329 {
18334 /* Swap PARM and ARG throughout the remainder of this
18335 function; the handling is precisely symmetric since PARM
18336 will initialize ARG rather than vice versa. */
18341 /* Core issue #873: Do the DR606 thing (see below) for these cases,
18342 too, but here handle it by stripping the reference from PARM
18343 rather than by adding it to ARG. */
18351 /* Nothing else to do in this case. */
18356 }
18359 {
18360 /* [temp.deduct.call]
18362 If P is not a reference type:
18364 --If A is an array type, the pointer type produced by the
18365 array-to-pointer standard conversion (_conv.array_) is
18366 used in place of A for type deduction; otherwise,
18368 --If A is a function type, the pointer type produced by
18369 the function-to-pointer standard conversion
18370 (_conv.func_) is used in place of A for type deduction;
18371 otherwise,
18373 --If A is a cv-qualified type, the top level
18374 cv-qualifiers of A's type are ignored for type
18375 deduction. */
18380 else
18382 }
18384 /* From C++0x [14.8.2.1/3 temp.deduct.call] (after DR606), "If P is
18385 of the form T&&, where T is a template parameter, and the argument
18386 is an lvalue, T is deduced as A& */
18392 /* try_one_overload doesn't provide an arg_expr, but
18393 functions are always lvalues. */
18397 /* [temp.deduct.call]
18399 If P is a cv-qualified type, the top level cv-qualifiers
18400 of P's type are ignored for type deduction. If P is a
18401 reference type, the type referred to by P is used for
18402 type deduction. */
18405 {
18408 }
18410 /* DR 322. For conversion deduction, remove a reference type on parm
18411 too (which has been swapped into ARG). */
18416 }
18418 /* Subroutine of unify_one_argument. PARM is a function parameter of a
18419 template which does contain any deducible template parameters; check if
18420 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
18421 unify_one_argument. */
18423 static int
18426 {
18427 tree type;
18431 else
18438 {
18442 }
18444 {
18449 }
18453 else
18455 }
18459 /* Returns true iff the expression EXPR is one from which a template
18460 argument can be deduced. In other words, if it's an undecorated
18461 use of a template non-type parameter. */
18463 static bool
18465 {
18466 /* Strip implicit conversions. */
18470 }
18472 /* Returns true iff the array domain DOMAIN uses a template parameter in a
18473 deducible way; that is, if it has a max value of <PARM> - 1. */
18475 static bool
18477 {
18486 }
18488 /* Returns true iff the template arguments ARGS use a template parameter
18489 in a deducible way. */
18491 static bool
18493 {
18495 {
18500 else
18501 {
18508 else
18510 }
18513 }
18515 }
18517 /* Returns true iff TYPE contains any deducible references to template
18518 parameters, as per 14.8.2.5. */
18520 static bool
18522 {
18526 /* T
18527 cv-list T
18528 TT<T>
18529 TT<i>
18530 TT<> */
18535 /* T*
18536 T&
18537 T&& */
18541 /* T[integer-constant ]
18542 type [i] */
18547 /* T type ::*
18548 type T::*
18549 T T::*
18550 T (type ::*)()
18551 type (T::*)()
18552 type (type ::*)(T)
18553 type (T::*)(T)
18554 T (type ::*)(T)
18555 T (T::*)()
18556 T (T::*)(T) */
18559 || (uses_deducible_template_parms
18562 /* template-name <T> (where template-name refers to a class template)
18563 template-name <i> (where template-name refers to a class template) */
18570 /* type (T)
18571 T()
18572 T(T) */
18575 {
18584 }
18587 }
18589 /* Subroutine of type_unification_real and unify_pack_expansion to
18590 handle unification of a single P/A pair. Parameters are as
18591 for those functions. */
18593 static int
18597 {
18604 /* We can't deduce anything from this, but we might get all the
18605 template args from other function args. */
18608 /* Implicit conversions (Clause 4) will be performed on a function
18609 argument to convert it to the type of the corresponding function
18610 parameter if the parameter type contains no template-parameters that
18611 participate in template argument deduction. */
18614 /* For function parameters with no deducible template parameters,
18615 just return. We'll check non-dependent conversions later. */
18619 {
18621 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
18622 | UNIFY_ALLOW_MORE_CV_QUAL
18636 }
18638 /* We only do these transformations if this is the top-level
18639 parameter_type_list in a call or declaration matching; in other
18640 situations (nested function declarators, template argument lists) we
18641 won't be comparing a type to an expression, and we don't do any type
18642 adjustments. */
18644 {
18646 {
18649 {
18650 /* [temp.deduct.type] A template-argument can be
18651 deduced from a pointer to function or pointer
18652 to member function argument if the set of
18653 overloaded functions does not contain function
18654 templates and at most one of a set of
18655 overloaded functions provides a unique
18656 match. */
18663 }
18669 }
18671 arg_strict |=
18673 }
18674 else
18679 /* For deduction from an init-list we need the actual list. */
18683 }
18685 /* for_each_template_parm callback that always returns 0. */
18687 static int
18689 {
18691 }
18693 /* for_each_template_parm any_fn callback to handle deduction of a template
18694 type argument from the type of an array bound. */
18696 static int
18698 {
18706 {
18712 }
18714 /* Keep walking. */
18716 }
18718 /* Try to deduce any not-yet-deduced template type arguments from the type of
18719 an array bound. This is handled separately from unify because 14.8.2.5 says
18720 "The type of a type parameter is only deduced from an array bound if it is
18721 not otherwise deduced." */
18723 static void
18725 {
18730 }
18732 /* Most parms like fn_type_unification.
18734 If SUBR is 1, we're being called recursively (to unify the
18735 arguments of a function or method parameter of a function
18736 template).
18738 CHECKS is a pointer to a vector of access checks encountered while
18739 substituting default template arguments. */
18741 static int
18743 tree full_targs,
18744 tree xparms,
18748 unification_kind_t strict,
18752 {
18757 tree parms;
18768 /* Reset the number of non-defaulted template arguments contained
18769 in TARGS. */
18772 again:
18780 {
18785 /* For a function parameter pack that occurs at the end of the
18786 parameter-declaration-list, the type A of each remaining
18787 argument of the call is compared with the type P of the
18788 declarator-id of the function parameter pack. */
18794 /* For a function parameter pack that does not occur at the
18795 end of the parameter-declaration-list, the type of the
18796 parameter pack is a non-deduced context. */
18803 explain_p))
18805 }
18810 {
18811 /* Unify the remaining arguments with the pack expansion type. */
18812 tree argvec;
18815 /* Allocate a TREE_VEC and copy in all of the arguments */
18820 /* Copy the parameter into parmvec. */
18826 /* Advance to the end of the list of parameters. */
18828 }
18830 /* Fail if we've reached the end of the parm list, and more args
18831 are present, and the parm list isn't variadic. */
18834 /* Fail if parms are left and they don't have default values and
18835 they aren't all deduced as empty packs (c++/57397). This is
18836 consistent with sufficient_parms_p. */
18839 {
18843 do
18844 {
18847 count++;
18849 }
18853 type_pack_p);
18854 }
18857 {
18858 tsubst_flags_t complain = (explain_p
18859 ? tf_warning_or_error
18864 {
18868 /* Clear the "incomplete" flags on all argument packs now so that
18869 substituting them into later default arguments works. */
18871 {
18874 }
18882 {
18887 }
18889 /* If this is an undeduced nontype parameter that depends on
18890 a type parameter, try another pass; its type may have been
18891 deduced from a later argument than the one from which
18892 this parameter can be deduced. */
18896 {
18899 }
18901 /* Core issue #226 (C++0x) [temp.deduct]:
18903 If a template argument has not been deduced, its
18904 default template argument, if any, is used.
18906 When we are in C++98 mode, TREE_PURPOSE will either
18907 be NULL_TREE or ERROR_MARK_NODE, so we do not need
18908 to explicitly check cxx_dialect here. */
18910 /* OK, there is a default argument. Wait until after the
18911 conversion check to do substitution. */
18914 /* If the type parameter is a parameter pack, then it will
18915 be deduced to an empty parameter pack. */
18917 {
18918 tree arg;
18921 {
18925 }
18926 else
18933 }
18936 }
18938 /* DR 1391: All parameters have args, now check non-dependent parms for
18939 convertibility. */
18943 {
18949 /* For a function parameter pack that occurs at the end of the
18950 parameter-declaration-list, the type A of each remaining
18951 argument of the call is compared with the type P of the
18952 declarator-id of the function parameter pack. */
18958 /* For a function parameter pack that does not occur at the
18959 end of the parameter-declaration-list, the type of the
18960 parameter pack is a non-deduced context. */
18969 explain_p))
18971 }
18973 /* Now substitute into the default template arguments. */
18975 {
18999 else
19007 {
19009 /* The position of the first default template argument,
19010 is also the number of non-defaulted arguments in TARGS.
19011 Record that. */
19014 }
19015 }
19019 }
19025 }
19027 /* Subroutine of type_unification_real. Args are like the variables
19028 at the call site. ARG is an overloaded function (or template-id);
19029 we try deducing template args from each of the overloads, and if
19030 only one succeeds, we go with that. Modifies TARGS and returns
19031 true on success. */
19033 static bool
19035 tree targs,
19036 tree parm,
19037 tree arg,
19038 unification_kind_t strict,
19041 {
19048 {
19051 }
19052 else
19056 /* Handle `&x' where `x' is some static or non-static member
19057 function name. */
19063 /* Strip baselink information. */
19068 {
19069 /* If we got some explicit template args, we need to plug them into
19070 the affected templates before we try to unify, in case the
19071 explicit args will completely resolve the templates in question. */
19078 {
19091 {
19096 {
19099 }
19100 }
19103 }
19104 /* If no templates (or more than one) are fully resolved by the
19105 explicit arguments, this template-id is a non-deduced context; it
19106 could still be OK if we deduce all template arguments for the
19107 enclosing call through other arguments. */
19110 }
19113 /* If ARG is, for example, "(0, &f)" then its type will be unknown
19114 -- but the deduction does not succeed because the expression is
19115 not just the function on its own. */
19117 else
19123 {
19126 }
19128 /* [temp.deduct.type] A template-argument can be deduced from a pointer
19129 to function or pointer to member function argument if the set of
19130 overloaded functions does not contain function templates and at most
19131 one of a set of overloaded functions provides a unique match.
19133 So if we found multiple possibilities, we return success but don't
19134 deduce anything. */
19137 {
19141 {
19146 /* Don't forget explicit template arguments in a pack. */
19150 }
19151 }
19156 }
19158 /* Core DR 115: In contexts where deduction is done and fails, or in
19159 contexts where deduction is not done, if a template argument list is
19160 specified and it, along with any default template arguments, identifies
19161 a single function template specialization, then the template-id is an
19162 lvalue for the function template specialization. */
19164 tree
19166 {
19179 {
19182 }
19184 {
19187 }
19189 {
19192 }
19195 {
19199 /* If we got some explicit template args, we need to plug them into
19200 the affected templates before we try to unify, in case the
19201 explicit args will completely resolve the templates in question. */
19209 {
19222 {
19225 {
19228 }
19230 {
19233 }
19234 }
19235 }
19237 {
19245 {
19246 tree base
19249 }
19253 }
19255 /* There were no good options and at least one bad one, so let the
19256 user know what the problem is. */
19258 }
19260 }
19262 /* Subroutine of resolve_overloaded_unification; does deduction for a single
19263 overload. Fills TARGS with any deduced arguments, or error_mark_node if
19264 different overloads deduce different arguments for a given parm.
19265 ADDR_P is true if the expression for which deduction is being
19266 performed was of the form "& fn" rather than simply "fn".
19268 Returns 1 on success. */
19270 static int
19272 tree orig_targs,
19273 tree targs,
19274 tree parm,
19275 tree arg,
19276 unification_kind_t strict,
19280 {
19282 tree tempargs;
19288 /* [temp.deduct.type] A template-argument can be deduced from a pointer
19289 to function or pointer to member function argument if the set of
19290 overloaded functions does not contain function templates and at most
19291 one of a set of overloaded functions provides a unique match.
19293 So if this is a template, just return success. */
19305 /* We don't copy orig_targs for this because if we have already deduced
19306 some template args from previous args, unify would complain when we
19307 try to deduce a template parameter for the same argument, even though
19308 there isn't really a conflict. */
19315 /* First make sure we didn't deduce anything that conflicts with
19316 explicitly specified args. */
19318 {
19325 /* Since we're unifying against ourselves, we will fill in
19326 template args used in the function parm list with our own
19327 template parms. Discard them. */
19330 {
19331 /* Check that the argument at each index of the deduced argument pack
19332 is equivalent to the corresponding explicitly specified argument.
19333 We may have deduced more arguments than were explicitly specified,
19334 and that's OK. */
19350 }
19353 }
19356 {
19361 }
19364 }
19366 /* PARM is a template class (perhaps with unbound template
19367 parameters). ARG is a fully instantiated type. If ARG can be
19368 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
19369 TARGS are as for unify. */
19371 static tree
19374 {
19375 tree copy_of_targs;
19382 /* We need to make a new template argument vector for the call to
19383 unify. If we used TARGS, we'd clutter it up with the result of
19384 the attempted unification, even if this class didn't work out.
19385 We also don't want to commit ourselves to all the unifications
19386 we've already done, since unification is supposed to be done on
19387 an argument-by-argument basis. In other words, consider the
19388 following pathological case:
19390 template <int I, int J, int K>
19391 struct S {};
19393 template <int I, int J>
19394 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
19396 template <int I, int J, int K>
19397 void f(S<I, J, K>, S<I, I, I>);
19399 void g() {
19400 S<0, 0, 0> s0;
19401 S<0, 1, 2> s2;
19403 f(s0, s2);
19404 }
19406 Now, by the time we consider the unification involving `s2', we
19407 already know that we must have `f<0, 0, 0>'. But, even though
19408 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
19409 because there are two ways to unify base classes of S<0, 1, 2>
19410 with S<I, I, I>. If we kept the already deduced knowledge, we
19411 would reject the possibility I=1. */
19414 /* If unification failed, we're done. */
19420 }
19422 /* Given a template type PARM and a class type ARG, find the unique
19423 base type in ARG that is an instance of PARM. We do not examine
19424 ARG itself; only its base-classes. If there is not exactly one
19425 appropriate base class, return NULL_TREE. PARM may be the type of
19426 a partial specialization, as well as a plain template type. Used
19427 by unify. */
19429 static enum template_base_result
19432 {
19434 tree binfo;
19440 {
19441 /* The type could not be completed. */
19444 }
19446 /* Walk in inheritance graph order. The search order is not
19447 important, and this avoids multiple walks of virtual bases. */
19449 {
19454 {
19455 /* If there is more than one satisfactory baseclass, then:
19457 [temp.deduct.call]
19459 If they yield more than one possible deduced A, the type
19460 deduction fails.
19462 applies. */
19464 {
19467 }
19470 }
19471 }
19475 }
19477 /* Returns the level of DECL, which declares a template parameter. */
19479 static int
19481 {
19483 {
19493 }
19495 }
19497 /* Decide whether ARG can be unified with PARM, considering only the
19498 cv-qualifiers of each type, given STRICT as documented for unify.
19499 Returns nonzero iff the unification is OK on that basis. */
19501 static int
19503 {
19509 {
19510 /* Although a CVR qualifier is ignored when being applied to a
19511 substituted template parameter ([8.3.2]/1 for example), that
19512 does not allow us to unify "const T" with "int&" because both
19513 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
19514 It is ok when we're allowing additional CV qualifiers
19515 at the outer level [14.8.2.1]/3,1st bullet. */
19525 }
19536 }
19538 /* Determines the LEVEL and INDEX for the template parameter PARM. */
19539 void
19541 {
19545 {
19548 }
19549 else
19550 {
19553 }
19554 }
19556 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
19557 do { \
19558 if (unify (TP, TA, P, A, S, EP)) \
19559 return 1; \
19560 } while (0)
19562 /* Unifies the remaining arguments in PACKED_ARGS with the pack
19563 expansion at the end of PACKED_PARMS. Returns 0 if the type
19564 deduction succeeds, 1 otherwise. STRICT is the same as in
19565 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
19566 function call argument list. We'll need to adjust the arguments to make them
19567 types. SUBR tells us if this is from a recursive call to
19568 type_unification_real, or for comparing two template argument
19569 lists. */
19571 static int
19575 {
19576 tree parm
19586 /* Determine the parameter packs we will be deducing from the
19587 pattern, and record their current deductions. */
19590 {
19594 /* Determine the index and level of this parameter pack. */
19597 /* Keep track of the parameter packs and their corresponding
19598 argument packs. */
19601 }
19603 /* Loop through all of the arguments that have not yet been
19604 unified and unify each with the pattern. */
19606 {
19607 tree parm;
19611 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
19612 or the element of its argument pack at the current index if
19613 this argument was explicitly specified. */
19615 {
19624 {
19627 }
19629 }
19631 /* If we had explicit template arguments, substitute them into the
19632 pattern before deduction. */
19634 {
19635 /* Some arguments might still be unspecified or dependent. */
19643 NULL_TREE);
19648 }
19649 else
19652 /* Unify the pattern with the current argument. */
19654 explain_p))
19657 /* For each parameter pack, collect the deduced value. */
19659 {
19665 }
19666 }
19668 /* Verify that the results of unification with the parameter packs
19669 produce results consistent with what we've seen before, and make
19670 the deduced argument packs available. */
19672 {
19679 /* By default keep the original deduced argument pack.
19680 If necessary, more specific code is going to update the
19681 resulting deduced argument later down in this function. */
19685 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
19686 actually deduce anything. */
19694 {
19695 /* If we had fewer function args than explicit template args,
19696 just use the explicits. */
19701 }
19704 {
19705 tree result;
19706 /* Build the deduced *_ARGUMENT_PACK. */
19708 {
19713 }
19714 else
19719 /* Note the deduced argument packs for this parameter
19720 pack. */
19722 }
19726 {
19727 /* We only had the explicitly-provided arguments before, but
19728 now we have a complete set of arguments. */
19734 }
19735 else
19736 {
19742 /* Inconsistent unification of this parameter pack. */
19744 bad_old_arg,
19745 bad_new_arg);
19746 }
19747 }
19750 }
19752 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
19753 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
19754 parameters and return value are as for unify. */
19756 static int
19760 {
19761 tree parm_max;
19762 tree arg_max;
19766 /* Our representation of array types uses "N - 1" as the
19767 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
19768 not an integer constant. We cannot unify arbitrarily
19769 complex expressions, so we eliminate the MINUS_EXPRs
19770 here. */
19774 {
19777 }
19781 {
19782 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
19783 trying to unify the type of a variable with the type
19784 of a template parameter. For example:
19786 template <unsigned int N>
19787 void f (char (&) [N]);
19788 int g();
19789 void h(int i) {
19790 char a[g(i)];
19791 f(a);
19792 }
19794 Here, the type of the ARG will be "int [g(i)]", and
19795 may be a SAVE_EXPR, etc. */
19799 }
19801 /* If only one of the bounds used a MINUS_EXPR, compensate
19802 by adding one to the other bound. */
19805 integer_type_node,
19806 parm_max,
19807 integer_one_node);
19810 integer_type_node,
19811 arg_max,
19812 integer_one_node);
19816 }
19818 /* Deduce the value of template parameters. TPARMS is the (innermost)
19819 set of template parameters to a template. TARGS is the bindings
19820 for those template parameters, as determined thus far; TARGS may
19821 include template arguments for outer levels of template parameters
19822 as well. PARM is a parameter to a template function, or a
19823 subcomponent of that parameter; ARG is the corresponding argument.
19824 This function attempts to match PARM with ARG in a manner
19825 consistent with the existing assignments in TARGS. If more values
19826 are deduced, then TARGS is updated.
19828 Returns 0 if the type deduction succeeds, 1 otherwise. The
19829 parameter STRICT is a bitwise or of the following flags:
19831 UNIFY_ALLOW_NONE:
19832 Require an exact match between PARM and ARG.
19833 UNIFY_ALLOW_MORE_CV_QUAL:
19834 Allow the deduced ARG to be more cv-qualified (by qualification
19835 conversion) than ARG.
19836 UNIFY_ALLOW_LESS_CV_QUAL:
19837 Allow the deduced ARG to be less cv-qualified than ARG.
19838 UNIFY_ALLOW_DERIVED:
19839 Allow the deduced ARG to be a template base class of ARG,
19840 or a pointer to a template base class of the type pointed to by
19841 ARG.
19842 UNIFY_ALLOW_INTEGER:
19843 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
19844 case for more information.
19845 UNIFY_ALLOW_OUTER_LEVEL:
19846 This is the outermost level of a deduction. Used to determine validity
19847 of qualification conversions. A valid qualification conversion must
19848 have const qualified pointers leading up to the inner type which
19849 requires additional CV quals, except at the outer level, where const
19850 is not required [conv.qual]. It would be normal to set this flag in
19851 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
19852 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
19853 This is the outermost level of a deduction, and PARM can be more CV
19854 qualified at this point.
19855 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
19856 This is the outermost level of a deduction, and PARM can be less CV
19857 qualified at this point. */
19859 static int
19862 {
19864 tree targ;
19865 tree tparm;
19867 tsubst_flags_t complain = (explain_p
19868 ? tf_warning_or_error
19871 /* I don't think this will do the right thing with respect to types.
19872 But the only case I've seen it in so far has been array bounds, where
19873 signedness is the only information lost, and I think that will be
19874 okay. */
19882 /* We can't deduce anything from this, but we might get all the
19883 template args from other function args. */
19886 /* If PARM uses template parameters, then we can't bail out here,
19887 even if ARG == PARM, since we won't record unifications for the
19888 template parameters. We might need them if we're trying to
19889 figure out which of two things is more specialized. */
19893 /* Handle init lists early, so the rest of the function can assume
19894 we're dealing with a type. */
19896 {
19901 /* Replace T with std::initializer_list<T> for deduction. */
19908 /* We can only deduce from an initializer list argument if the
19909 parameter is std::initializer_list or an array; otherwise this
19910 is a non-deduced context. */
19915 else
19916 {
19918 /* Deduction is defined in terms of a single type, so just punt
19919 on the (bizarre) std::initializer_list<T...>. */
19922 }
19925 {
19932 {
19936 /* It should only be possible to get here for a call. */
19938 elt_strict |= maybe_adjust_types_for_deduction
19941 }
19944 explain_p);
19945 }
19949 {
19950 /* Also deduce from the length of the initializer list. */
19957 }
19959 /* If the std::initializer_list<T> deduction worked, replace the
19960 deduced A with std::initializer_list<A>. */
19962 {
19967 }
19969 }
19971 /* Immediately reject some pairs that won't unify because of
19972 cv-qualification mismatches. */
19975 /* It is the elements of the array which hold the cv quals of an array
19976 type, and the elements might be template type parms. We'll check
19977 when we recurse. */
19979 /* We check the cv-qualifiers when unifying with template type
19980 parameters below. We want to allow ARG `const T' to unify with
19981 PARM `T' for example, when computing which of two templates
19982 is more specialized, for example. */
19996 {
20000 /* In a type which contains a nested-name-specifier, template
20001 argument values cannot be deduced for template parameters used
20002 within the nested-name-specifier. */
20014 /* The PARM is not one we're trying to unify. Just check
20015 to see if it matches ARG. */
20016 {
20021 else
20023 }
20030 /* Check for mixed types and values. */
20038 {
20039 /* ARG must be constructed from a template class or a template
20040 template parameter. */
20044 {
20048 tree parm_parms
20049 = DECL_INNERMOST_TEMPLATE_PARMS
20054 /* The resolution to DR150 makes clear that default
20055 arguments for an N-argument may not be used to bind T
20056 to a template template parameter with fewer than N
20057 parameters. It is not safe to permit the binding of
20058 default arguments as an extension, as that may change
20059 the meaning of a conforming program. Consider:
20061 struct Dense { static const unsigned int dim = 1; };
20063 template <template <typename> class View,
20064 typename Block>
20065 void operator+(float, View<Block> const&);
20067 template <typename Block,
20068 unsigned int Dim = Block::dim>
20069 struct Lvalue_proxy { operator float() const; };
20071 void
20072 test_1d (void) {
20073 Lvalue_proxy<Dense> p;
20074 float b;
20075 b + p;
20076 }
20078 Here, if Lvalue_proxy is permitted to bind to View, then
20079 the global operator+ will be used; if they are not, the
20080 Lvalue_proxy will be converted to float. */
20082 full_argvec,
20084 complain,
20090 /* Deduce arguments T, i from TT<T> or TT<i>.
20091 We check each element of PARMVEC and ARGVEC individually
20092 rather than the whole TREE_VEC since they can have
20093 different number of elements. */
20100 /* Check if the parameters end in a pack, making them
20101 variadic. */
20107 /* If the template argument list of P contains a pack
20108 expansion that is not the last template argument, the
20109 entire template argument list is a non-deduced
20110 context. */
20119 {
20124 }
20129 DEDUCE_EXACT,
20132 }
20135 /* Fall through to deduce template name. */
20136 }
20140 {
20141 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
20143 /* Simple cases: Value already set, does match or doesn't. */
20148 }
20149 else
20150 {
20151 /* If PARM is `const T' and ARG is only `int', we don't have
20152 a match unless we are allowing additional qualification.
20153 If ARG is `const int' and PARM is just `T' that's OK;
20154 that binds `const int' to `T'. */
20159 /* Consider the case where ARG is `const volatile int' and
20160 PARM is `const T'. Then, T should be `volatile int'. */
20161 arg = cp_build_qualified_type_real
20166 /* Simple cases: Value already set, does match or doesn't. */
20172 /* Make sure that ARG is not a variable-sized array. (Note
20173 that were talking about variable-sized arrays (like
20174 `int[n]'), rather than arrays of unknown size (like
20175 `int[]').) We'll get very confused by such a type since
20176 the bound of the array is not constant, and therefore
20177 not mangleable. Besides, such types are not allowed in
20178 ISO C++, so we can do as we please here. We do allow
20179 them for 'auto' deduction, since that isn't ABI-exposed. */
20183 /* Strip typedefs as in convert_template_argument. */
20185 }
20187 /* If ARG is a parameter pack or an expansion, we cannot unify
20188 against it unless PARM is also a parameter pack. */
20193 /* If the argument deduction results is a METHOD_TYPE,
20194 then there is a problem.
20195 METHOD_TYPE doesn't map to any real C++ type the result of
20196 the deduction can not be of that type. */
20210 {
20211 /* The PARM is not one we're trying to unify. Just check
20212 to see if it matches ARG. */
20218 }
20224 {
20229 }
20232 /* We deduce from array bounds in try_array_deduction. */
20236 {
20241 }
20243 /* [temp.deduct.type] If, in the declaration of a function template
20244 with a non-type template-parameter, the non-type
20245 template-parameter is used in an expression in the function
20246 parameter-list and, if the corresponding template-argument is
20247 deduced, the template-argument type shall match the type of the
20248 template-parameter exactly, except that a template-argument
20249 deduced from an array bound may be of any integral type.
20250 The non-type parameter might use already deduced type parameters. */
20253 {
20257 }
20260 /* Template-parameter dependent expression. Just accept it for now.
20261 It will later be processed in convert_template_argument. */
20262 ;
20267 /* Convert the ARG to the type of PARM; the deduced non-type
20268 template argument must exactly match the types of the
20269 corresponding parameter. */
20272 /* We haven't deduced the type of this parameter yet. Try again
20273 later. */
20275 else
20278 /* If ARG is a parameter pack or an expansion, we cannot unify
20279 against it unless PARM is also a parameter pack. */
20284 {
20287 }
20292 {
20293 /* A pointer-to-member constant can be unified only with
20294 another constant. */
20298 /* Just unify the class member. It would be useless (and possibly
20299 wrong, depending on the strict flags) to unify also
20300 PTRMEM_CST_CLASS, because we want to be sure that both parm and
20301 arg refer to the same variable, even if through different
20302 classes. For instance:
20304 struct A { int x; };
20305 struct B : A { };
20307 Unification of &A::x and &B::x must succeed. */
20310 }
20313 {
20317 /* [temp.deduct.call]
20319 A can be another pointer or pointer to member type that can
20320 be converted to the deduced A via a qualification
20321 conversion (_conv.qual_).
20323 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
20324 This will allow for additional cv-qualification of the
20325 pointed-to types if appropriate. */
20328 /* The derived-to-base conversion only persists through one
20329 level of pointers. */
20334 }
20366 /* We have already checked cv-qualification at the top of the
20367 function. */
20371 /* As far as unification is concerned, this wins. Later checks
20372 will invalidate it if necessary. */
20375 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
20376 /* Type INTEGER_CST can come from ordinary constant template args. */
20388 {
20398 /* Check for pack expansions in the parameters. */
20400 {
20402 {
20404 /* We can unify against something with a trailing
20405 parameter pack. */
20407 else
20408 /* [temp.deduct.type]/9: If the template argument list of
20409 P contains a pack expansion that is not the last
20410 template argument, the entire template argument list
20411 is a non-deduced context. */
20413 }
20414 }
20416 /* If we don't have enough arguments to satisfy the parameters
20417 (not counting the pack expression at the end), or we have
20418 too many arguments for a parameter list that doesn't end in
20419 a pack expression, we can't unify. */
20425 /* Unify all of the parameters that precede the (optional)
20426 pack expression. */
20428 {
20433 }
20436 DEDUCE_EXACT,
20439 }
20447 {
20455 }
20460 {
20464 {
20465 /* First, we try to unify the PARM and ARG directly. */
20470 {
20471 /* Fallback to the special case allowed in
20472 [temp.deduct.call]:
20474 If P is a class, and P has the form
20475 template-id, then A can be a derived class of
20476 the deduced A. Likewise, if P is a pointer to
20477 a class of the form template-id, A can be a
20478 pointer to a derived class pointed to by the
20479 deduced A. */
20485 {
20486 /* Don't give the derived diagnostic if we're
20487 already dealing with the same template. */
20488 bool same_template
20494 }
20495 }
20496 }
20500 /* Perhaps PARM is something like S<U> and ARG is S<int>.
20501 Then, we should unify `int' and `U'. */
20503 else
20504 /* There's no chance of unification succeeding. */
20509 }
20516 {
20519 tree a;
20525 /* CV qualifications for methods can never be deduced, they must
20526 match exactly. We need to check them explicitly here,
20527 because type_unification_real treats them as any other
20528 cv-qualified parameter. */
20530 && (!check_cv_quals_for_unify
20558 {
20570 }
20573 }
20576 /* Unify a pointer to member with a pointer to member function, which
20577 deduces the type of the member as a function type. */
20579 {
20580 /* Check top-level cv qualifiers */
20588 /* Determine the type of the function we are unifying against. */
20592 }
20611 /* Matched cases are handled by the ARG == PARM test above. */
20615 /* We might get a variable as a non-type template argument in parm if the
20616 corresponding parameter is type-dependent. Make any necessary
20617 adjustments based on whether arg is a reference. */
20621 {
20626 }
20627 /* Now use the normal expression code to check whether they match. */
20638 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
20639 or UNDERLYING_TYPE nodes. */
20643 /* Unification fails if we hit an error node. */
20648 {
20653 }
20654 /* FALLTHRU */
20657 /* An unresolved overload is a nondeduced context. */
20661 expr:
20662 /* We must be looking at an expression. This can happen with
20663 something like:
20665 template <int I>
20666 void foo(S<I>, S<I + 2>);
20668 This is a "nondeduced context":
20670 [deduct.type]
20672 The nondeduced contexts are:
20674 --A type that is a template-id in which one or more of
20675 the template-arguments is an expression that references
20676 a template-parameter.
20678 In these cases, we assume deduction succeeded, but don't
20679 actually infer any unifications. */
20684 else
20686 }
20687 }
20688 #undef RECUR_AND_CHECK_FAILURE
20689 \f
20690 /* Note that DECL can be defined in this translation unit, if
20691 required. */
20693 static void
20695 {
20696 tree clone;
20700 }
20702 /* Called if RESULT is explicitly instantiated, or is a member of an
20703 explicitly instantiated class. */
20705 void
20707 {
20710 /* If this entity has already been written out, it's too late to
20711 make any modifications. */
20715 /* For anonymous namespace we don't need to do anything. */
20717 {
20720 }
20723 /* The TREE_PUBLIC flag for function declarations will have been
20724 set correctly by tsubst. */
20727 /* This might have been set by an earlier implicit instantiation. */
20732 else
20733 {
20736 /* Always make artificials weak. */
20739 /* For WIN32 we also want to put explicit instantiations in
20740 linkonce sections. */
20743 }
20745 /* If EXTERN_P, then this function will not be emitted -- unless
20746 followed by an explicit instantiation, at which point its linkage
20747 will be adjusted. If !EXTERN_P, then this function will be
20748 emitted here. In neither circumstance do we want
20749 import_export_decl to adjust the linkage. */
20751 }
20753 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
20754 important template arguments. If any are missing, we check whether
20755 they're important by using error_mark_node for substituting into any
20756 args that were used for partial ordering (the ones between ARGS and END)
20757 and seeing if it bubbles up. */
20759 static bool
20761 {
20766 {
20769 }
20771 {
20775 }
20777 }
20779 /* Given two function templates PAT1 and PAT2, return:
20781 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
20782 -1 if PAT2 is more specialized than PAT1.
20783 0 if neither is more specialized.
20785 LEN indicates the number of parameters we should consider
20786 (defaulted parameters should not be considered).
20788 The 1998 std underspecified function template partial ordering, and
20789 DR214 addresses the issue. We take pairs of arguments, one from
20790 each of the templates, and deduce them against each other. One of
20791 the templates will be more specialized if all the *other*
20792 template's arguments deduce against its arguments and at least one
20793 of its arguments *does* *not* deduce against the other template's
20794 corresponding argument. Deduction is done as for class templates.
20795 The arguments used in deduction have reference and top level cv
20796 qualifiers removed. Iff both arguments were originally reference
20797 types *and* deduction succeeds in both directions, an lvalue reference
20798 wins against an rvalue reference and otherwise the template
20799 with the more cv-qualified argument wins for that pairing (if
20800 neither is more cv-qualified, they both are equal). Unlike regular
20801 deduction, after all the arguments have been deduced in this way,
20802 we do *not* verify the deduced template argument values can be
20803 substituted into non-deduced contexts.
20805 The logic can be a bit confusing here, because we look at deduce1 and
20806 targs1 to see if pat2 is at least as specialized, and vice versa; if we
20807 can find template arguments for pat1 to make arg1 look like arg2, that
20808 means that arg2 is at least as specialized as arg1. */
20810 int
20812 {
20825 /* Remove the this parameter from non-static member functions. If
20826 one is a non-static member function and the other is not a static
20827 member function, remove the first parameter from that function
20828 also. This situation occurs for operator functions where we
20829 locate both a member function (with this pointer) and non-member
20830 operator (with explicit first operand). */
20832 {
20837 }
20839 {
20842 {
20843 len--;
20845 }
20846 }
20848 /* If only one is a conversion operator, they are unordered. */
20852 /* Consider the return type for a conversion function */
20854 {
20857 len++;
20858 }
20860 processing_template_decl++;
20866 /* Stop when an ellipsis is seen. */
20868 {
20879 {
20880 /* When both arguments are pack expansions, we need only
20881 unify the patterns themselves. */
20885 /* This is the last comparison we need to do. */
20887 }
20890 {
20894 }
20897 {
20901 }
20907 {
20913 /* Setup the parameter vector, which contains only ARG1. */
20916 /* Setup the argument vector, which contains the remaining
20917 arguments. */
20926 /* We cannot deduce in the other direction, because ARG1 is
20927 a pack expansion but ARG2 is not. */
20929 }
20931 {
20937 /* Setup the parameter vector, which contains only ARG1. */
20940 /* Setup the argument vector, which contains the remaining
20941 arguments. */
20950 /* We cannot deduce in the other direction, because ARG2 is
20951 a pack expansion but ARG1 is not.*/
20953 }
20955 else
20956 {
20957 /* The normal case, where neither argument is a pack
20958 expansion. */
20965 }
20967 /* If we couldn't deduce arguments for tparms1 to make arg1 match
20968 arg2, then arg2 is not as specialized as arg1. */
20974 /* "If, for a given type, deduction succeeds in both directions
20975 (i.e., the types are identical after the transformations above)
20976 and both P and A were reference types (before being replaced with
20977 the type referred to above):
20978 - if the type from the argument template was an lvalue reference and
20979 the type from the parameter template was not, the argument type is
20980 considered to be more specialized than the other; otherwise,
20981 - if the type from the argument template is more cv-qualified
20982 than the type from the parameter template (as described above),
20983 the argument type is considered to be more specialized than the other;
20984 otherwise,
20985 - neither type is more specialized than the other." */
20988 {
20990 {
20993 else
20995 }
20997 {
21002 }
21003 }
21006 /* We've failed to deduce something in either direction.
21007 These must be unordered. */
21012 /* We have already processed all of the arguments in our
21013 handing of the pack expansion type. */
21018 }
21020 /* "In most cases, all template parameters must have values in order for
21021 deduction to succeed, but for partial ordering purposes a template
21022 parameter may remain without a value provided it is not used in the
21023 types being used for partial ordering."
21025 Thus, if we are missing any of the targs1 we need to substitute into
21026 origs1, then pat2 is not as specialized as pat1. This can happen when
21027 there is a nondeduced context. */
21033 processing_template_decl--;
21035 /* If both deductions succeed, the partial ordering selects the more
21036 constrained template. */
21038 {
21043 }
21045 /* All things being equal, if the next argument is a pack expansion
21046 for one function but not for the other, prefer the
21047 non-variadic function. FIXME this is bogus; see c++/41958. */
21051 {
21054 }
21060 else
21062 }
21064 /* Determine which of two partial specializations of TMPL is more
21065 specialized.
21067 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
21068 to the first partial specialization. The TREE_PURPOSE is the
21069 innermost set of template parameters for the partial
21070 specialization. PAT2 is similar, but for the second template.
21072 Return 1 if the first partial specialization is more specialized;
21073 -1 if the second is more specialized; 0 if neither is more
21074 specialized.
21076 See [temp.class.order] for information about determining which of
21077 two templates is more specialized. */
21079 static int
21081 {
21082 tree targs;
21091 /* Just like what happens for functions, if we are ordering between
21092 different template specializations, we may encounter dependent
21093 types in the arguments, and we need our dependency check functions
21094 to behave correctly. */
21098 {
21101 }
21105 {
21108 }
21111 /* If both deductions succeed, the partial ordering selects the more
21112 constrained template. */
21116 /* In the case of a tie where at least one of the templates
21117 has a parameter pack at the end, the template with the most
21118 non-packed parameters wins. */
21120 && any_deductions
21123 {
21129 /* We don't count the pack expansion at the end. */
21139 }
21142 }
21144 /* Return the template arguments that will produce the function signature
21145 DECL from the function template FN, with the explicit template
21146 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
21147 also match. Return NULL_TREE if no satisfactory arguments could be
21148 found. */
21150 static tree
21152 {
21156 tree decl_arg_types;
21159 tree arg;
21163 /* Never do unification on the 'this' parameter. */
21184 }
21186 /* Return the innermost template arguments that, when applied to a partial
21187 specialization SPEC_TMPL of TMPL, yield the ARGS.
21189 For example, suppose we have:
21191 template <class T, class U> struct S {};
21192 template <class T> struct S<T*, int> {};
21194 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
21195 partial specialization and the ARGS will be {double*, int}. The resulting
21196 vector will be {double}, indicating that `T' is bound to `double'. */
21198 static tree
21200 {
21202 tree spec_args
21205 tree deduced_args;
21206 tree innermost_deduced_args;
21210 {
21214 innermost_deduced_args);
21215 }
21216 else
21220 again:
21229 {
21231 {
21237 }
21239 }
21243 {
21246 }
21248 /* Verify that nondeduced template arguments agree with the type
21249 obtained from argument deduction.
21251 For example:
21253 struct A { typedef int X; };
21254 template <class T, class U> struct C {};
21255 template <class T> struct C<T, typename T::X> {};
21257 Then with the instantiation `C<A, int>', we can deduce that
21258 `T' is `A' but unify () does not check whether `typename T::X'
21259 is `int'. */
21268 /* We only need to check the innermost arguments; the other
21269 arguments will always agree. */
21274 /* Now that we have bindings for all of the template arguments,
21275 ensure that the arguments deduced for the template template
21276 parameters have compatible template parameter lists. See the use
21277 of template_template_parm_bindings_ok_p in fn_type_unification
21278 for more information. */
21283 }
21285 // Compare two function templates T1 and T2 by deducing bindings
21286 // from one against the other. If both deductions succeed, compare
21287 // constraints to see which is more constrained.
21288 static int
21290 {
21295 {
21298 }
21301 {
21304 }
21306 // If both deductions succeed, then one may be more constrained.
21311 }
21313 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
21314 Return the TREE_LIST node with the most specialized template, if
21315 any. If there is no most specialized template, the error_mark_node
21316 is returned.
21318 Note that this function does not look at, or modify, the
21319 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
21320 returned is one of the elements of INSTANTIATIONS, callers may
21321 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
21322 and retrieve it from the value returned. */
21324 tree
21326 {
21333 {
21338 {
21339 /* Equally specialized, move to next function. If there
21340 is no next function, nothing's most specialized. */
21345 }
21346 }
21349 /* Now verify that champ is better than everything earlier in the
21350 instantiation list. */
21353 {
21356 }
21357 }
21359 processing_template_decl--;
21365 }
21367 /* If DECL is a specialization of some template, return the most
21368 general such template. Otherwise, returns NULL_TREE.
21370 For example, given:
21372 template <class T> struct S { template <class U> void f(U); };
21374 if TMPL is `template <class U> void S<int>::f(U)' this will return
21375 the full template. This function will not trace past partial
21376 specializations, however. For example, given in addition:
21378 template <class T> struct S<T*> { template <class U> void f(U); };
21380 if TMPL is `template <class U> void S<int*>::f(U)' this will return
21381 `template <class T> template <class U> S<T*>::f(U)'. */
21383 tree
21385 {
21387 {
21390 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
21391 template friend, or a FIELD_DECL for a capture pack. */
21394 }
21396 /* Look for more and more general templates. */
21398 {
21399 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
21400 (See cp-tree.h for details.) */
21409 /* Stop if we run into an explicitly specialized class template. */
21416 }
21419 }
21421 /* Return the most specialized of the template partial specializations
21422 which can produce TARGET, a specialization of some class or variable
21423 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
21424 a TEMPLATE_DECL node corresponding to the partial specialization, while
21425 the TREE_PURPOSE is the set of template arguments that must be
21426 substituted into the template pattern in order to generate TARGET.
21428 If the choice of partial specialization is ambiguous, a diagnostic
21429 is issued, and the error_mark_node is returned. If there are no
21430 partial specializations matching TARGET, then NULL_TREE is
21431 returned, indicating that the primary template should be used. */
21433 static tree
21435 {
21437 tree t;
21438 tree champ;
21445 {
21449 }
21451 {
21454 }
21456 {
21460 }
21461 else
21466 /* For determining which partial specialization to use, only the
21467 innermost args are interesting. */
21469 {
21472 }
21475 {
21476 tree spec_args;
21480 {
21481 /* Substitute in the template args from the enclosing class. */
21485 }
21492 {
21496 /* Keep the candidate only if the constraints are satisfied,
21497 or if we're not compiling with concepts. */
21500 {
21503 }
21504 }
21505 }
21515 {
21518 ;
21519 else
21520 {
21522 {
21525 {
21528 }
21529 }
21531 }
21532 }
21536 {
21539 {
21542 }
21543 }
21546 {
21553 else
21557 {
21562 }
21565 }
21568 }
21570 /* Explicitly instantiate DECL. */
21572 void
21574 {
21579 /* An error occurred, for which grokdeclarator has already issued
21580 an appropriate message. */
21583 {
21586 }
21592 {
21593 /* There is an asymmetry here in the way VAR_DECLs and
21594 FUNCTION_DECLs are handled by grokdeclarator. In the case of
21595 the latter, the DECL we get back will be marked as a
21596 template instantiation, and the appropriate
21597 DECL_TEMPLATE_INFO will be set up. This does not happen for
21598 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
21599 should handle VAR_DECLs as it currently handles
21600 FUNCTION_DECLs. */
21602 {
21605 }
21608 {
21611 }
21613 {
21618 }
21619 }
21621 {
21624 }
21625 else
21628 /* Check for various error cases. Note that if the explicit
21629 instantiation is valid the RESULT will currently be marked as an
21630 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
21631 until we get here. */
21634 {
21635 /* DR 259 [temp.spec].
21637 Both an explicit instantiation and a declaration of an explicit
21638 specialization shall not appear in a program unless the explicit
21639 instantiation follows a declaration of the explicit specialization.
21641 For a given set of template parameters, if an explicit
21642 instantiation of a template appears after a declaration of an
21643 explicit specialization for that template, the explicit
21644 instantiation has no effect. */
21646 }
21648 {
21649 /* [temp.spec]
21651 No program shall explicitly instantiate any template more
21652 than once.
21654 We check DECL_NOT_REALLY_EXTERN so as not to complain when
21655 the first instantiation was `extern' and the second is not,
21656 and EXTERN_P for the opposite case. */
21659 /* If an "extern" explicit instantiation follows an ordinary
21660 explicit instantiation, the template is instantiated. */
21663 }
21665 {
21668 }
21670 {
21673 }
21676 ;
21678 {
21681 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
21684 }
21685 else
21693 }
21695 static void
21697 {
21703 {
21706 }
21707 }
21709 /* Called from do_type_instantiation through binding_table_foreach to
21710 do recursive instantiation for the type bound in ENTRY. */
21711 static void
21713 {
21719 }
21721 /* Called from do_type_instantiation to instantiate a member
21722 (a member function or a static member variable) of an
21723 explicitly instantiated class template. */
21724 static void
21726 {
21731 }
21733 /* Perform an explicit instantiation of template class T. STORAGE, if
21734 non-null, is the RID for extern, inline or static. COMPLAIN is
21735 nonzero if this is called from the parser, zero if called recursively,
21736 since the standard is unclear (as detailed below). */
21738 void
21740 {
21750 {
21751 tree tmpl =
21755 else
21758 }
21763 {
21766 t);
21768 }
21771 {
21773 {
21775 {
21778 "ISO C++ 1998 forbids the use of %<extern%> on "
21780 }
21781 else
21783 "ISO C++ forbids the use of %qE"
21785 }
21793 else
21794 {
21796 storage);
21798 }
21799 }
21802 {
21803 /* DR 259 [temp.spec].
21805 Both an explicit instantiation and a declaration of an explicit
21806 specialization shall not appear in a program unless the explicit
21807 instantiation follows a declaration of the explicit specialization.
21809 For a given set of template parameters, if an explicit
21810 instantiation of a template appears after a declaration of an
21811 explicit specialization for that template, the explicit
21812 instantiation has no effect. */
21814 }
21816 {
21817 /* [temp.spec]
21819 No program shall explicitly instantiate any template more
21820 than once.
21822 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
21823 instantiation was `extern'. If EXTERN_P then the second is.
21824 These cases are OK. */
21831 /* If we've already instantiated the template, just return now. */
21834 }
21842 {
21843 tree tmp;
21845 /* In contrast to implicit instantiation, where only the
21846 declarations, and not the definitions, of members are
21847 instantiated, we have here:
21849 [temp.explicit]
21851 The explicit instantiation of a class template specialization
21852 implies the instantiation of all of its members not
21853 previously explicitly specialized in the translation unit
21854 containing the explicit instantiation.
21856 Of course, we can't instantiate member template classes, since
21857 we don't have any arguments for them. Note that the standard
21858 is unclear on whether the instantiation of the members are
21859 *explicit* instantiations or not. However, the most natural
21860 interpretation is that it should be an explicit instantiation. */
21876 }
21877 }
21879 /* Given a function DECL, which is a specialization of TMPL, modify
21880 DECL to be a re-instantiation of TMPL with the same template
21881 arguments. TMPL should be the template into which tsubst'ing
21882 should occur for DECL, not the most general template.
21884 One reason for doing this is a scenario like this:
21886 template <class T>
21887 void f(const T&, int i);
21889 void g() { f(3, 7); }
21891 template <class T>
21892 void f(const T& t, const int i) { }
21894 Note that when the template is first instantiated, with
21895 instantiate_template, the resulting DECL will have no name for the
21896 first parameter, and the wrong type for the second. So, when we go
21897 to instantiate the DECL, we regenerate it. */
21899 static void
21901 {
21902 /* The arguments used to instantiate DECL, from the most general
21903 template. */
21904 tree code_pattern;
21908 /* Make sure that we can see identifiers, and compute access
21909 correctly. */
21913 {
21914 tree decl_parm;
21915 tree pattern_parm;
21916 tree specs;
21930 specs);
21932 /* Merge parameter declarations. */
21935 pattern_parm
21939 {
21940 tree parm_type;
21941 tree attributes;
21946 NULL_TREE);
21952 {
21955 }
21958 }
21959 /* Merge any parameters that match with the function parameter
21960 pack. */
21962 {
21964 tree expanded_types;
21965 /* Expand the TYPE_PACK_EXPANSION that provides the types for
21966 the parameters in this function parameter pack. */
21971 {
21972 tree parm_type;
21973 tree attributes;
21976 /* Rename the parameter to include the index. */
21985 {
21988 }
21990 }
21991 }
21992 /* Merge additional specifiers from the CODE_PATTERN. */
21996 }
21998 {
22006 }
22007 else
22011 }
22013 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
22014 substituted to get DECL. */
22016 tree
22018 {
22021 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
22022 for the instantiation. This is not always the most general
22023 template. Consider, for example:
22025 template <class T>
22026 struct S { template <class U> void f();
22027 template <> void f<int>(); };
22029 and an instantiation of S<double>::f<int>. We want TD to be the
22030 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
22032 more general template. */
22034 /* We must also deal with friend templates. Given:
22036 template <class T> struct S {
22037 template <class U> friend void f() {};
22038 };
22040 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
22041 so far as the language is concerned, but that's still
22042 where we get the pattern for the instantiation from. On
22043 other hand, if the definition comes outside the class, say:
22045 template <class T> struct S {
22046 template <class U> friend void f();
22047 };
22048 template <class U> friend void f() {}
22050 we don't need to look any further. That's what the check for
22051 DECL_INITIAL is for. */
22055 {
22056 /* The present template, TD, should not be a definition. If it
22057 were a definition, we should be using it! Note that we
22058 cannot restructure the loop to just keep going until we find
22059 a template with a definition, since that might go too far if
22060 a specialization was declared, but not defined. */
22062 /* Fetch the more general template. */
22064 }
22067 }
22069 /* Returns true if we need to instantiate this template instance even if we
22070 know we aren't going to emit it. */
22072 bool
22074 {
22075 /* We always instantiate inline functions so that we can inline them. An
22076 explicit instantiation declaration prohibits implicit instantiation of
22077 non-inline functions. With high levels of optimization, we would
22078 normally inline non-inline functions -- but we're not allowed to do
22079 that for "extern template" functions. Therefore, we check
22080 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
22084 /* And we need to instantiate static data members so that
22085 their initializers are available in integral constant
22086 expressions. */
22089 }
22091 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
22092 instantiate it now, modifying TREE_TYPE (fn). */
22094 void
22096 {
22099 /* Don't instantiate a noexcept-specification from template context. */
22114 {
22118 {
22133 }
22134 else
22138 }
22141 {
22144 else
22146 }
22147 }
22149 /* Produce the definition of D, a _DECL generated from a template. If
22150 DEFER_OK is nonzero, then we don't have to actually do the
22151 instantiation now; we just have to do it sometime. Normally it is
22152 an error if this is an explicit instantiation but D is undefined.
22153 EXPL_INST_CLASS_MEM_P is true iff D is a member of an
22154 explicitly instantiated class template. */
22156 tree
22159 {
22161 tree gen_args;
22162 tree args;
22163 tree td;
22164 tree code_pattern;
22165 tree spec;
22166 tree gen_tmpl;
22173 tree fn_context;
22176 /* This function should only be used to instantiate templates for
22177 functions and static member variables. */
22180 /* A concept is never instantiated. */
22183 /* Variables are never deferred; if instantiation is required, they
22184 are instantiated right away. That allows for better code in the
22185 case that an expression refers to the value of the variable --
22186 if the variable has a constant value the referring expression can
22187 take advantage of that fact. */
22191 /* Don't instantiate cloned functions. Instead, instantiate the
22192 functions they cloned. */
22200 /* D has already been instantiated or explicitly specialized, so
22201 there's nothing for us to do here.
22203 It might seem reasonable to check whether or not D is an explicit
22204 instantiation, and, if so, stop here. But when an explicit
22205 instantiation is deferred until the end of the compilation,
22206 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
22207 the instantiation. */
22210 /* Check to see whether we know that this template will be
22211 instantiated in some other file, as with "extern template"
22212 extension. */
22215 /* In general, we do not instantiate such templates. */
22223 /* We should already have the extra args. */
22226 /* And what's in the hash table should match D. */
22230 /* This needs to happen before any tsubsting. */
22236 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
22237 for the instantiation. */
22242 {
22243 /* Look up an explicit specialization, if any. */
22247 {
22250 }
22251 }
22255 /* We should never be trying to instantiate a member of a class
22256 template or partial specialization. */
22261 /* In the case of a friend template whose definition is provided
22262 outside the class, we may have too many arguments. Drop the
22263 ones we don't need. The same is true for specializations. */
22264 args = get_innermost_template_args
22268 {
22274 }
22275 else
22276 {
22281 else
22283 }
22285 /* We may be in the middle of deferred access check. Disable it now. */
22288 /* Unless an explicit instantiation directive has already determined
22289 the linkage of D, remember that a definition is available for
22290 this entity. */
22300 /* If D is a member of an explicitly instantiated class template,
22301 and no definition is available, treat it like an implicit
22302 instantiation. */
22305 {
22306 /* Leave linkage flags alone on instantiations with anonymous
22307 visibility. */
22309 {
22312 }
22314 }
22316 /* Defer all other templates, unless we have been explicitly
22317 forbidden from doing so. */
22319 template. */
22320 ! pattern_defined
22321 /* If it's OK to postpone instantiation, do so. */
22322 || defer_ok
22323 /* If this is a static data member that will be defined
22324 elsewhere, we don't want to instantiate the entire data
22325 member, but we do want to instantiate the initializer so that
22326 we can substitute that elsewhere. */
22328 /* Handle here a deleted function too, avoid generating
22329 its body (c++/61080). */
22331 {
22332 /* The definition of the static data member is now required so
22333 we must substitute the initializer. */
22337 {
22338 tree ns;
22339 tree init;
22348 args,
22351 /* If instantiating the initializer involved instantiating this
22352 again, don't call cp_finish_decl twice. */
22354 {
22355 /* Make sure the initializer is still constant, in case of
22356 circular dependency (template/instantiate6.C). */
22357 const_init
22361 LOOKUP_ONLYCONVERTING);
22362 }
22366 }
22368 /* We restore the source position here because it's used by
22369 add_pending_template. */
22375 /* [temp.explicit]
22377 The definition of a non-exported function template, a
22378 non-exported member function template, or a non-exported
22379 member function or static data member of a class template
22380 shall be present in every translation unit in which it is
22381 explicitly instantiated. */
22385 /* If we're in unevaluated context, we just wanted to get the
22386 constant value; this isn't an odr use, so don't queue
22387 a full instantiation. */
22390 /* ??? Historically, we have instantiated inline functions, even
22391 when marked as "extern template". */
22395 }
22396 /* Tell the repository that D is available in this translation unit
22397 -- and see if it is supposed to be instantiated here. */
22399 {
22400 /* In a PCH file, despite the fact that the repository hasn't
22401 requested instantiation in the PCH it is still possible that
22402 an instantiation will be required in a file that includes the
22403 PCH. */
22406 /* Instantiate inline functions so that the inliner can do its
22407 job, even though we'll not be emitting a copy of this
22408 function. */
22411 }
22421 else
22422 {
22427 }
22429 /* Mark D as instantiated so that recursive calls to
22430 instantiate_decl do not try to instantiate it again. */
22433 /* Regenerate the declaration in case the template has been modified
22434 by a subsequent redeclaration. */
22437 /* We already set the file and line above. Reset them now in case
22438 they changed as a result of calling regenerate_decl_from_template. */
22442 {
22443 tree init;
22446 /* Clear out DECL_RTL; whatever was there before may not be right
22447 since we've reset the type of the declaration. */
22451 /* The initializer is placed in DECL_INITIAL by
22452 regenerate_decl_from_template so we don't need to
22453 push/pop_access_scope again here. Pull it out so that
22454 cp_finish_decl can process it. */
22459 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
22460 initializer. That function will defer actual emission until
22461 we have a chance to determine linkage. */
22464 /* Enter the scope of D so that access-checking works correctly. */
22477 }
22481 {
22483 tree tmpl_parm;
22484 tree spec_parm;
22487 /* Save away the current list, in case we are instantiating one
22488 template from within the body of another. */
22491 /* Set up the list of local specializations. */
22494 /* Set up context. */
22498 else
22501 /* Some typedefs referenced from within the template code need to be
22502 access checked at template instantiation time, i.e now. These
22503 types were added to the template at parsing time. Let's get those
22504 and perform the access checks then. */
22506 args);
22508 /* Create substitution entries for the parameters. */
22512 {
22516 }
22518 {
22520 {
22523 }
22524 else
22525 {
22526 /* Register the (value) argument pack as a specialization of
22527 TMPL_PARM, then move on. */
22530 }
22531 }
22534 /* Substitute into the body of the function. */
22538 else
22539 {
22544 /* Set the current input_location to the end of the function
22545 so that finish_function knows where we are. */
22546 input_location
22549 /* Remember if we saw an infinite loop in the template. */
22550 current_function_infinite_loop
22552 }
22554 /* We don't need the local specializations any more. */
22558 /* Finish the function. */
22562 else
22563 {
22566 }
22570 }
22572 /* We're not deferring instantiation any more. */
22580 out:
22592 }
22594 /* Run through the list of templates that we wish we could
22595 instantiate, and instantiate any we can. RETRIES is the
22596 number of times we retry pending template instantiation. */
22598 void
22600 {
22604 /* Instantiating templates may trigger vtable generation. This in turn
22605 may require further template instantiations. We place a limit here
22606 to avoid infinite loop. */
22608 {
22612 "template instantiation depth exceeds maximum of %d"
22613 " instantiating %q+D, possibly from virtual table generation"
22617 /* Pretend that we defined it. */
22620 }
22622 do
22623 {
22628 {
22633 {
22634 tree fn;
22637 {
22641 fn;
22649 }
22652 }
22653 else
22654 {
22657 {
22658 instantiation
22664 }
22668 }
22671 /* If INSTANTIATION has been instantiated, then we don't
22672 need to consider it again in the future. */
22674 else
22675 {
22678 }
22681 }
22683 }
22687 }
22689 /* Substitute ARGVEC into T, which is a list of initializers for
22690 either base class or a non-static data member. The TREE_PURPOSEs
22691 are DECLs, and the TREE_VALUEs are the initializer values. Used by
22692 instantiate_decl. */
22694 static tree
22696 {
22700 {
22701 tree decl;
22702 tree init;
22708 {
22709 tree expr;
22710 tree arg;
22712 /* Expand the base class expansion type into separate base
22713 classes. */
22715 tf_warning_or_error,
22716 NULL_TREE);
22720 /* We'll be building separate TREE_LISTs of arguments for
22721 each base. */
22727 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
22728 expand each argument in the TREE_VALUE of t. */
22735 /* VOID_TYPE_NODE is used to indicate
22736 value-initialization. */
22737 {
22740 }
22741 else
22742 {
22743 /* Substitute parameter packs into each argument in the
22744 TREE_LIST. */
22747 {
22748 tree expanded_exprs;
22750 /* Expand the argument. */
22752 expanded_exprs
22754 tf_warning_or_error,
22755 NULL_TREE);
22759 /* Prepend each of the expanded expressions to the
22760 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
22762 {
22767 }
22768 }
22771 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
22772 since we built them backwards. */
22774 {
22777 }
22778 }
22779 }
22782 {
22784 {
22788 }
22789 else
22790 {
22791 tree tmp;
22806 /* If we had an initializer but it instantiated to nothing,
22807 value-initialize the object. This will only occur when
22808 the initializer was a pack expansion where the parameter
22809 packs used in that expansion were of length zero. */
22812 }
22815 {
22819 }
22820 }
22821 }
22823 }
22825 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
22827 static void
22829 {
22834 else
22836 }
22838 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
22839 is the instantiation (which should have been created with
22840 start_enum) and ARGS are the template arguments to use. */
22842 static void
22844 {
22845 tree e;
22851 {
22852 tree value;
22853 tree decl;
22856 /* Note that in a template enum, the TREE_VALUE is the
22857 CONST_DECL, not the corresponding INTEGER_CST. */
22862 /* Give this enumeration constant the correct access. */
22865 /* Actually build the enumerator itself. Here we're assuming that
22866 enumerators can't have dependent attributes. */
22869 }
22879 }
22881 /* DECL is a FUNCTION_DECL that is a template specialization. Return
22882 its type -- but without substituting the innermost set of template
22883 arguments. So, innermost set of template parameters will appear in
22884 the type. */
22886 tree
22888 {
22889 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
22891 }
22893 /* Return truthvalue if we're processing a template different from
22894 the last one involved in diagnostics. */
22895 bool
22897 {
22899 }
22901 /* Remember current template involved in diagnostics. */
22902 void
22904 {
22906 }
22910 {
22912 }
22914 /* Return TRUE if current_function_decl is being instantiated, false
22915 otherwise. */
22917 bool
22919 {
22922 }
22924 /* [temp.param] Check that template non-type parm TYPE is of an allowable
22925 type. Return zero for ok, nonzero for disallowed. Issue error and
22926 warning messages under control of COMPLAIN. */
22928 static int
22930 {
22945 /* A bound template template parm could later be instantiated to have a valid
22946 nontype parm type via an alias template. */
22952 {
22955 else
22957 type);
22958 }
22960 }
22962 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
22963 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
22965 static bool
22967 {
22968 tree scope;
22970 /* [temp.dep.type]
22972 A type is dependent if it is:
22974 -- a template parameter. Template template parameters are types
22975 for us (since TYPE_P holds true for them) so we handle
22976 them here. */
22980 /* -- a qualified-id with a nested-name-specifier which contains a
22981 class-name that names a dependent type or whose unqualified-id
22982 names a dependent type. */
22986 /* An alias template specialization can be dependent even if the
22987 resulting type is not. */
22991 /* -- a cv-qualified type where the cv-unqualified type is
22992 dependent.
22993 No code is necessary for this bullet; the code below handles
22994 cv-qualified types, and we don't want to strip aliases with
22995 TYPE_MAIN_VARIANT because of DR 1558. */
22996 /* -- a compound type constructed from any dependent type. */
23006 {
23007 tree arg_type;
23012 arg_type;
23017 }
23018 /* -- an array type constructed from any dependent type or whose
23019 size is specified by a constant expression that is
23020 value-dependent.
23022 We checked for type- and value-dependence of the bounds in
23023 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
23025 {
23030 }
23032 /* -- a template-id in which either the template name is a template
23033 parameter ... */
23036 /* ... or any of the template arguments is a dependent type or
23037 an expression that is type-dependent or value-dependent. */
23039 && (any_dependent_template_arguments_p
23043 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
23044 dependent; if the argument of the `typeof' expression is not
23045 type-dependent, then it should already been have resolved. */
23051 /* A template argument pack is dependent if any of its packed
23052 arguments are. */
23054 {
23060 }
23062 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
23063 be template parameters. */
23070 /* The standard does not specifically mention types that are local
23071 to template functions or local classes, but they should be
23072 considered dependent too. For example:
23074 template <int I> void f() {
23075 enum E { a = I };
23076 S<sizeof (E)> s;
23077 }
23079 The size of `E' cannot be known until the value of `I' has been
23080 determined. Therefore, `E' must be considered dependent. */
23084 /* Don't use type_dependent_expression_p here, as it can lead
23085 to infinite recursion trying to determine whether a lambda
23086 nested in a lambda is dependent (c++/47687). */
23090 && (any_dependent_template_arguments_p
23094 /* Other types are non-dependent. */
23096 }
23098 /* Returns TRUE if TYPE is dependent, in the sense of
23099 [temp.dep.type]. Note that a NULL type is considered dependent. */
23101 bool
23103 {
23104 /* If there are no template parameters in scope, then there can't be
23105 any dependent types. */
23107 {
23108 /* If we are not processing a template, then nobody should be
23109 providing us with a dependent type. */
23113 }
23115 /* If the type is NULL, we have not computed a type for the entity
23116 in question; in that case, the type is dependent. */
23120 /* Erroneous types can be considered non-dependent. */
23124 /* If we have not already computed the appropriate value for TYPE,
23125 do so now. */
23127 {
23130 }
23133 }
23135 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
23136 lookup. In other words, a dependent type that is not the current
23137 instantiation. */
23139 bool
23141 {
23144 }
23146 /* T is a SCOPE_REF; return whether we need to consider it
23147 instantiation-dependent so that we can check access at instantiation
23148 time even though we know which member it resolves to. */
23150 static bool
23152 {
23158 else
23160 }
23162 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
23163 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
23164 expression. */
23166 /* Note that this predicate is not appropriate for general expressions;
23167 only constant expressions (that satisfy potential_constant_expression)
23168 can be tested for value dependence. */
23170 bool
23172 {
23176 /* A name declared with a dependent type. */
23181 {
23183 /* A dependent member function of the current instantiation. */
23187 /* A dependent member function of the current instantiation. */
23194 /* A name that has not been looked up -- must be dependent. */
23198 /* A non-type template parm. */
23202 /* A non-type template parm. */
23208 /* A constant with literal type and is initialized
23209 with an expression that is value-dependent.
23211 Note that a non-dependent parenthesized initializer will have
23212 already been replaced with its constant value, so if we see
23213 a TREE_LIST it must be dependent. */
23217 /* cp_finish_decl doesn't fold reference initializers. */
23229 /* These expressions are value-dependent if the type to which
23230 the cast occurs is dependent or the expression being casted
23231 is value-dependent. */
23232 {
23238 /* A functional cast has a list of operands. */
23241 {
23242 /* If there are no operands, it must be an expression such
23243 as "int()". This should not happen for aggregate types
23244 because it would form non-constant expressions. */
23249 }
23255 }
23260 /* FALLTHRU */
23263 /* A `sizeof' expression is value-dependent if the operand is
23264 type-dependent or is a pack expansion. */
23273 /* An 'encode' expression is value-dependent if the operand is
23274 type-dependent. */
23283 /* All instantiation-dependent expressions should also be considered
23284 value-dependent. */
23292 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
23293 is value-dependent. */
23294 {
23303 }
23306 {
23310 }
23321 {
23325 }
23328 /* Treat all requires-expressions as value-dependent so
23329 we don't try to fold them. */
23336 {
23343 {
23345 /* In a call to a constexpr member function, look through the
23346 implicit ADDR_EXPR on the object argument so that it doesn't
23347 cause the call to be considered value-dependent. We also
23348 look through it in potential_constant_expression. */
23355 }
23357 }
23360 /* If a TEMPLATE_ID_EXPR involves a dependent name, it will be
23361 type-dependent. */
23366 {
23368 tree val;
23375 }
23378 /* Treat a GNU statement expression as dependent to avoid crashing
23379 under instantiate_non_dependent_expr; it can't be constant. */
23383 /* A constant expression is value-dependent if any subexpression is
23384 value-dependent. */
23386 {
23393 {
23397 {
23400 /* In some cases, some of the operands may be missing.l
23401 (For example, in the case of PREDECREMENT_EXPR, the
23402 amount to increment by may be missing.) That doesn't
23403 make the expression dependent. */
23406 }
23407 }
23411 }
23413 }
23415 /* The expression is not value-dependent. */
23417 }
23419 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
23420 [temp.dep.expr]. Note that an expression with no type is
23421 considered dependent. Other parts of the compiler arrange for an
23422 expression with type-dependent subexpressions to have no type, so
23423 this function doesn't have to be fully recursive. */
23425 bool
23427 {
23434 /* An unresolved name is always dependent. */
23440 /* A fold expression is type-dependent. */
23447 /* Some expression forms are never type-dependent. */
23461 /* The types of these expressions depends only on the type to which
23462 the cast occurs. */
23471 /* The types of these expressions depends only on the type created
23472 by the expression. */
23475 {
23476 /* For NEW_EXPR tree nodes created inside a template, either
23477 the object type itself or a TREE_LIST may appear as the
23478 operand 1. */
23481 /* This is an array type. We need to check array dimensions
23482 as well. */
23484 || value_dependent_expression_p
23486 else
23488 }
23491 {
23495 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
23496 contains an identifier associated by name lookup with one or more
23497 declarations declared with a dependent type, or...a
23498 nested-name-specifier or qualified-id that names a member of an
23499 unknown specialization. */
23502 }
23512 {
23513 tree elt;
23517 {
23520 }
23522 }
23524 /* A static data member of the current instantiation with incomplete
23525 array type is type-dependent, as the definition and specializations
23526 can have different bounds. */
23533 /* An array of unknown bound depending on a variadic parameter, eg:
23535 template<typename... Args>
23536 void foo (Args... args)
23537 {
23538 int arr[] = { args... };
23539 }
23541 template<int... vals>
23542 void bar ()
23543 {
23544 int arr[] = { vals... };
23545 }
23547 If the array has no length and has an initializer, it must be that
23548 we couldn't determine its length in cp_complete_array_type because
23549 it is dependent. */
23556 /* A function or variable template-id is type-dependent if it has any
23557 dependent template arguments. Note that we only consider the innermost
23558 template arguments here, since those are the ones that come from the
23559 template-id; the template arguments for the enclosing class do not make it
23560 type-dependent, they only make a member function value-dependent. */
23565 && (any_dependent_template_arguments_p
23569 /* Always dependent, on the number of arguments if nothing else. */
23574 {
23579 {
23585 }
23586 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
23591 {
23596 }
23599 {
23606 }
23612 {
23616 }
23618 }
23622 /* Dependent type attributes might not have made it from the decl to
23623 the type yet. */
23629 }
23631 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
23632 type-dependent if the expression refers to a member of the current
23633 instantiation and the type of the referenced member is dependent, or the
23634 class member access expression refers to a member of an unknown
23635 specialization.
23637 This function returns true if the OBJECT in such a class member access
23638 expression is of an unknown specialization. */
23640 bool
23642 {
23645 }
23647 /* walk_tree callback function for instantiation_dependent_expression_p,
23648 below. Returns non-zero if a dependent subexpression is found. */
23650 static tree
23653 {
23655 {
23656 /* We don't have to worry about decltype currently because decltype
23657 of an instantiation-dependent expr is a dependent type. This
23658 might change depending on the resolution of DR 1172. */
23661 }
23664 {
23665 /* Don't treat an argument list as dependent just because it has no
23666 TREE_TYPE. */
23674 /* Handle expressions with type operands. */
23679 {
23684 {
23687 else
23688 {
23691 }
23692 }
23694 }
23698 /* In a template, finish_class_member_access_expr creates a
23699 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
23700 type-dependent, so that we can check access control at
23701 instantiation time (PR 42277). See also Core issue 1273. */
23708 else
23711 /* Treat statement-expressions as dependent. */
23715 /* Treat requires-expressions as dependent. */
23720 /* Treat calls to function concepts as dependent. */
23726 /* And variable concepts. */
23733 }
23737 else
23739 }
23741 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
23742 sense defined by the ABI:
23744 "An expression is instantiation-dependent if it is type-dependent
23745 or value-dependent, or it has a subexpression that is type-dependent
23746 or value-dependent."
23748 Except don't actually check value-dependence for unevaluated expressions,
23749 because in sizeof(i) we don't care about the value of i. Checking
23750 type-dependence will in turn check value-dependence of array bounds/template
23751 arguments as needed. */
23753 bool
23755 {
23756 tree result;
23767 }
23769 /* As above, but also check value-dependence of the expression as a whole. */
23771 bool
23773 {
23776 }
23778 /* Like type_dependent_expression_p, but it also works while not processing
23779 a template definition, i.e. during substitution or mangling. */
23781 bool
23783 {
23789 }
23791 /* Returns TRUE if ARGS contains a type-dependent expression. */
23793 bool
23795 {
23797 tree arg;
23800 {
23803 }
23805 }
23807 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
23808 expressions) contains any type-dependent expressions. */
23810 bool
23812 {
23818 }
23820 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
23821 expressions) contains any value-dependent expressions. */
23823 bool
23825 {
23831 }
23833 /* Returns TRUE if the ARG (a template argument) is dependent. */
23835 bool
23837 {
23841 /* Assume a template argument that was wrongly written by the user
23842 is dependent. This is consistent with what
23843 any_dependent_template_arguments_p [that calls this function]
23844 does. */
23854 {
23857 /* A member template of a dependent class is not necessarily
23858 type-dependent, but it is a dependent template argument because it
23859 will be a member of an unknown specialization to that template. */
23862 }
23864 {
23868 {
23871 }
23874 }
23877 else
23880 }
23882 /* Returns true if ARGS (a collection of template arguments) contains
23883 any types that require structural equality testing. */
23885 bool
23887 {
23897 {
23900 {
23906 {
23907 /* Look inside the argument pack. */
23910 }
23913 {
23926 }
23927 }
23928 }
23931 }
23933 /* Returns true if ARGS (a collection of template arguments) contains
23934 any dependent arguments. */
23936 bool
23938 {
23948 {
23953 }
23956 }
23958 /* Returns TRUE if the template TMPL is type-dependent. */
23960 bool
23962 {
23964 {
23966 {
23970 }
23972 }
23974 /* Template template parameters are dependent. */
23978 /* So are names that have not been looked up. */
23982 }
23984 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
23986 bool
23988 {
23991 }
23993 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
23994 are dependent. */
23996 bool
23998 {
24005 {
24027 {
24031 }
24035 {
24039 {
24044 }
24045 }
24046 }
24049 }
24051 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
24052 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
24053 no such TYPE can be found. Note that this function peers inside
24054 uninstantiated templates and therefore should be used only in
24055 extremely limited situations. ONLY_CURRENT_P restricts this
24056 peering to the currently open classes hierarchy (which is required
24057 when comparing types). */
24059 tree
24061 {
24062 tree scope;
24063 tree name;
24064 tree decl;
24066 tree pushed_scope;
24067 tree result;
24072 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
24073 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
24074 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
24075 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
24076 identifier of the TYPENAME_TYPE anymore.
24077 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
24078 TYPENAME_TYPE instead, we avoid messing up with a possible
24079 typedef variant case. */
24082 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
24083 it first before we can figure out what NAME refers to. */
24085 {
24087 /* Given a class template A with a dependent base with nested type C,
24088 typedef typename A::C::C C will land us here, as trying to resolve
24089 the initial A::C leads to the local C typedef, which leads back to
24090 A::C::C. So we break the recursion now. */
24092 else
24094 }
24095 /* If we don't know what SCOPE refers to, then we cannot resolve the
24096 TYPENAME_TYPE. */
24099 /* If this is a typedef, we don't want to look inside (c++/11987). */
24102 /* If SCOPE isn't the template itself, it will not have a valid
24103 TYPE_FIELDS list. */
24105 /* scope is either the template itself or a compatible instantiation
24106 like X<T>, so look up the name in the original template. */
24108 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
24110 /* If scope has no fields, it can't be a current instantiation. Check this
24111 before currently_open_class to avoid infinite recursion (71515). */
24114 /* If the SCOPE is not the current instantiation, there's no reason
24115 to look inside it. */
24118 /* Enter the SCOPE so that name lookup will be resolved as if we
24119 were in the class definition. In particular, SCOPE will no
24120 longer be considered a dependent type. */
24122 /* Look up the declaration. */
24124 tf_warning_or_error);
24128 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
24129 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
24134 {
24138 }
24141 {
24142 tree tmpl;
24143 tree args;
24144 /* Obtain the template and the arguments. */
24147 /* Instantiate the template. */
24153 }
24155 /* Leave the SCOPE. */
24159 /* If we failed to resolve it, return the original typename. */
24163 /* If lookup found a typename type, resolve that too. */
24165 {
24166 /* Ill-formed programs can cause infinite recursion here, so we
24167 must catch that. */
24171 }
24173 /* Qualify the resulting type. */
24179 }
24181 /* EXPR is an expression which is not type-dependent. Return a proxy
24182 for EXPR that can be used to compute the types of larger
24183 expressions containing EXPR. */
24185 tree
24187 {
24188 tree inner_expr;
24190 /* When checking, try to get a constant value for all non-dependent
24191 expressions in order to expose bugs in *_dependent_expression_p
24192 and constexpr. This can affect code generation, see PR70704, so
24193 only do this for -fchecking=2. */
24196 /* Don't do this during nsdmi parsing as it can lead to
24197 unexpected recursive instantiations. */
24199 /* Don't do this during concept expansion either and for
24200 the same reason. */
24204 /* Preserve OVERLOADs; the functions must be available to resolve
24205 types. */
24216 /* There is no need to return a proxy for a variable. */
24219 /* Preserve string constants; conversions from string constants to
24220 "char *" are allowed, even though normally a "const char *"
24221 cannot be used to initialize a "char *". */
24224 /* Preserve void and arithmetic constants, as an optimization -- there is no
24225 reason to create a new node. */
24230 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
24231 There is at least one place where we want to know that a
24232 particular expression is a throw-expression: when checking a ?:
24233 expression, there are special rules if the second or third
24234 argument is a throw-expression. */
24238 /* Don't wrap an initializer list, we need to be able to look inside. */
24242 /* Don't wrap a dummy object, we need to be able to test for it. */
24261 /* If the type is unknown, it can't really be non-dependent */
24264 /* Otherwise, build a NON_DEPENDENT_EXPR. */
24266 }
24268 /* ARGS is a vector of expressions as arguments to a function call.
24269 Replace the arguments with equivalent non-dependent expressions.
24270 This modifies ARGS in place. */
24272 void
24274 {
24276 tree arg;
24279 {
24283 }
24284 }
24286 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
24287 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
24288 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
24290 static tree
24292 {
24306 }
24308 tree
24310 {
24312 }
24314 tree
24316 {
24318 }
24320 /* Return a C++17 deduction placeholder for class template TMPL. */
24322 tree
24324 {
24328 }
24330 /* Make a "constrained auto" type-specifier. This is an
24331 auto type with constraints that must be associated after
24332 deduction. The constraint is formed from the given
24333 CONC and its optional sequence of arguments, which are
24334 non-null if written as partial-concept-id. */
24336 tree
24338 {
24341 /* Build the constraint. */
24343 tree expr;
24346 else
24352 /* Our canonical type depends on the constraint. */
24355 /* Attach the constraint to the type declaration. */
24358 }
24360 /* Given type ARG, return std::initializer_list<ARG>. */
24362 static tree
24364 {
24365 tree std_init_list = namespace_binding
24367 tree argvec;
24369 {
24373 }
24378 }
24380 /* Replace auto in TYPE with std::initializer_list<auto>. */
24382 static tree
24384 {
24391 }
24393 /* Hash traits for hashing possibly constrained 'auto'
24394 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
24397 {
24400 };
24402 /* Hash the 'auto' T. */
24404 inline hashval_t
24406 {
24408 /* Matching constrained-type-specifiers denote the same template
24409 parameter, so hash the constraint. */
24411 else
24412 /* But unconstrained autos are all separate, so just hash the pointer. */
24414 }
24416 /* Compare two 'auto's. */
24420 {
24427 /* Two unconstrained autos are distinct. */
24432 }
24434 /* for_each_template_parm callback for extract_autos: if t is a (possibly
24435 constrained) auto, add it to the vector. */
24437 static int
24439 {
24442 {
24443 /* All the autos were built with index 0; fix that up now. */
24447 /* If this is a repeated constrained-type-specifier, use the index we
24448 chose before. */
24450 else
24451 {
24452 /* Otherwise this is new, so use the current count. */
24455 }
24457 }
24459 /* Always keep walking. */
24461 }
24463 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
24464 says they can appear anywhere in the type. */
24466 static tree
24468 {
24477 {
24482 }
24485 }
24487 /* The stem for deduction guide names. */
24490 /* Return the name for a deduction guide for class template TMPL. */
24492 tree
24494 {
24505 }
24507 /* True if NAME is the name of a deduction guide. */
24509 bool
24511 {
24515 }
24517 /* True if FN is a deduction guide. */
24519 bool
24521 {
24525 }
24527 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
24528 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
24529 template parameter types. Note that the handling of template template
24530 parameters relies on current_template_parms being set appropriately for the
24531 new template. */
24533 static tree
24536 {
24539 tree newtype;
24542 {
24545 }
24546 else
24550 tree newdecl
24555 tree newidx;
24558 {
24566 {
24571 // First create a copy (ttargs) of tsubst_args with an
24572 // additional level for the template template parameter's own
24573 // template parameters (ttparms).
24574 tree ttparms = (INNERMOST_TEMPLATE_PARMS
24582 // Substitute ttargs into ttparms to fix references to
24583 // other template parameters.
24585 complain);
24586 // Now substitute again with args based on tparms, to reduce
24587 // the level of the ttparms.
24590 complain);
24591 // Finally, tack the adjusted parms onto tparms.
24593 current_template_parms);
24595 }
24596 }
24597 else
24598 {
24600 tree newconst
24610 }
24615 }
24617 /* Returns a C++17 class deduction guide template based on the constructor
24618 CTOR. */
24620 static tree
24622 {
24626 tree fn_tmpl;
24628 {
24631 }
24632 else
24636 /* If type is a member class template, DECL_TI_ARGS (ctor) will have fully
24637 specialized args for the enclosing class. Strip those off, as the
24638 deduction guide won't have those template parameters. */
24641 /* Discard the 'this' parameter. */
24647 {
24648 /* For a member template constructor, we need to flatten the two template
24649 parameter lists into one, and then adjust the function signature
24650 accordingly. This gets...complicated. */
24654 /* For a member template we should have two levels of parms/args, one for
24655 the class and one for the constructor. We stripped specialized args
24656 for further enclosing classes above. */
24660 /* Template args for translating references to the two-level template
24661 parameters into references to the one-level template parameters we are
24662 creating. */
24667 /* Template parms for the constructor template. */
24670 /* Template parms for the class template. */
24674 /* Template parms for the deduction guide start as a copy of the template
24675 parms for the class. We set current_template_parms for
24676 lookup_template_class_1. */
24682 /* Now we need to rewrite the constructor parms to append them to the
24683 class parms. */
24685 {
24700 }
24702 /* Now we have a final set of template parms to substitute into the
24703 function signature. */
24713 }
24717 FUNCTION_DECL,
24728 }
24730 /* Deduce template arguments for the class template placeholder PTYPE for
24731 template TMPL based on the initializer INIT, and return the resulting
24732 type. */
24734 tree
24736 {
24738 {
24739 /* We should have handled this in the caller. */
24745 }
24754 else
24758 {
24759 /* First try to deduce directly, since we don't have implicitly-declared
24760 constructors yet. */
24769 }
24781 {
24784 }
24787 // FIXME cache artificial deduction guides
24789 {
24793 }
24796 {
24800 }
24809 }
24811 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
24812 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
24814 tree
24816 {
24818 tf_warning_or_error,
24819 adc_unspecified);
24820 }
24822 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
24823 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
24824 The CONTEXT determines the context in which auto deduction is performed
24825 and is used to control error diagnostics.
24827 For partial-concept-ids, extra args may be appended to the list of deduced
24828 template arguments prior to determining constraint satisfaction. */
24830 tree
24833 tree outer_targs)
24834 {
24835 tree targs;
24842 /* Defining a subset of type-dependent expressions that we can deduce
24843 from ahead of time isn't worth the trouble. */
24847 /* C++17 class template argument deduction. */
24850 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
24851 with either a new invented type template parameter U or, if the
24852 initializer is a braced-init-list (8.5.4), with
24853 std::initializer_list<U>. */
24855 {
24860 else
24861 {
24863 {
24867 "for deduction to %<std::initializer_list%>, use copy-"
24869 }
24871 }
24872 }
24883 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
24884 and initializer has array type, deduce cv-qualified array type. */
24886 complain);
24888 {
24897 {
24901 }
24902 }
24903 else
24904 {
24906 tree tparms;
24910 else
24911 {
24915 }
24922 {
24924 /* Try again at instantiation time. */
24928 /* If type is error_mark_node a diagnostic must have been
24929 emitted by now. Also, having a mention to '<type error>'
24930 in the diagnostic is not really useful to the user. */
24931 {
24935 else
24940 }
24942 }
24943 }
24945 /* Check any placeholder constraints against the deduced type. */
24948 {
24949 /* Use the deduced type to check the associated constraints. If we
24950 have a partial-concept-id, rebuild the argument list so that
24951 we check using the extra arguments. */
24955 {
24958 }
24959 else
24962 {
24964 {
24966 {
24984 }
24986 }
24988 }
24989 }
24995 }
24997 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
24998 result. */
25000 tree
25002 {
25004 {
25010 /* In an abbreviated function template we didn't know we were dealing
25011 with a function template when we saw the auto return type, so update
25012 it to have the correct level. */
25014 }
25016 }
25018 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
25019 'decltype(auto)' or a deduced class template. */
25021 bool
25023 {
25029 else
25031 }
25033 /* for_each_template_parm callback for type_uses_auto. */
25035 int
25037 {
25039 }
25041 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
25042 a use of `auto'. Returns NULL_TREE otherwise. */
25044 tree
25046 {
25050 {
25051 /* The Concepts TS allows multiple autos in one type-specifier; just
25052 return the first one we find, do_auto_deduction will collect all of
25053 them. */
25057 else
25059 }
25060 else
25062 }
25064 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto',
25065 'decltype(auto)' or a concept. */
25067 bool
25069 {
25071 }
25073 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing a generic type (`auto' or
25074 a concept identifier) iff TYPE contains a use of a generic type. Returns
25075 NULL_TREE otherwise. */
25077 tree
25079 {
25081 }
25084 /* For a given template T, return the vector of typedefs referenced
25085 in T for which access check is needed at T instantiation time.
25086 T is either a FUNCTION_DECL or a RECORD_TYPE.
25087 Those typedefs were added to T by the function
25088 append_type_to_template_for_access_check. */
25092 {
25093 tree ti;
25104 {
25109 }
25112 }
25114 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
25115 tied to T. That list of typedefs will be access checked at
25116 T instantiation time.
25117 T is either a FUNCTION_DECL or a RECORD_TYPE.
25118 TYPE_DECL is a TYPE_DECL node representing a typedef.
25119 SCOPE is the scope through which TYPE_DECL is accessed.
25120 LOCATION is the location of the usage point of TYPE_DECL.
25122 This function is a subroutine of
25123 append_type_to_template_for_access_check. */
25125 static void
25127 tree type_decl,
25128 tree scope,
25129 location_t location)
25130 {
25131 qualified_typedef_usage_t typedef_usage;
25132 tree ti;
25139 && type_decl
25153 }
25155 /* Append TYPE_DECL to the template TEMPL.
25156 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
25157 At TEMPL instanciation time, TYPE_DECL will be checked to see
25158 if it can be accessed through SCOPE.
25159 LOCATION is the location of the usage point of TYPE_DECL.
25161 e.g. consider the following code snippet:
25163 class C
25164 {
25165 typedef int myint;
25166 };
25168 template<class U> struct S
25169 {
25170 C::myint mi; // <-- usage point of the typedef C::myint
25171 };
25173 S<char> s;
25175 At S<char> instantiation time, we need to check the access of C::myint
25176 In other words, we need to check the access of the myint typedef through
25177 the C scope. For that purpose, this function will add the myint typedef
25178 and the scope C through which its being accessed to a list of typedefs
25179 tied to the template S. That list will be walked at template instantiation
25180 time and access check performed on each typedefs it contains.
25181 Note that this particular code snippet should yield an error because
25182 myint is private to C. */
25184 void
25186 tree type_decl,
25187 tree scope,
25188 location_t location)
25189 {
25195 /* Make sure we don't append the type to the template twice. */
25202 }
25204 /* Convert the generic type parameters in PARM that match the types given in the
25205 range [START_IDX, END_IDX) from the current_template_parms into generic type
25206 packs. */
25208 tree
25210 {
25221 {
25222 /* Create a distinct parameter pack type from the current parm and add it
25223 to the replacement args to tsubst below into the generic function
25224 parameter. */
25239 }
25245 /* If there are more levels then build up the replacement with the outer
25246 template parms. */
25250 replacement);
25253 }
25255 /* Entries in the decl_constraint hash table. */
25257 {
25258 tree decl;
25259 tree ci;
25260 };
25262 /* Hashing function and equality for constraint entries. */
25264 {
25266 {
25268 }
25271 {
25273 }
25274 };
25276 /* A mapping from declarations to constraint information. Note that
25277 both templates and their underlying declarations are mapped to the
25278 same constraint information.
25280 FIXME: This is defined in pt.c because garbage collection
25281 code is not being generated for constraint.cc. */
25285 /* Returns the template constraints of declaration T. If T is not
25286 constrained, return NULL_TREE. Note that T must be non-null. */
25288 tree
25290 {
25301 else
25303 }
25305 /* Associate the given constraint information CI with the declaration
25306 T. If T is a template, then the constraints are associated with
25307 its underlying declaration. Don't build associations if CI is
25308 NULL_TREE. */
25310 void
25312 {
25324 }
25326 /* Remove the associated constraints of the declaration T. */
25328 void
25330 {
25339 }
25341 /* Memoized satisfaction results for declarations. This
25342 maps the pair (constraint_info, arguments) to the result computed
25343 by constraints_satisfied_p. */
25346 {
25347 tree ci;
25348 tree args;
25349 tree result;
25350 };
25352 /* Hashing function and equality for constraint entries. */
25355 {
25357 {
25360 }
25363 {
25365 }
25366 };
25368 /* Memoized satisfaction results for concept checks. */
25371 {
25372 tree tmpl;
25373 tree args;
25374 tree result;
25375 };
25377 /* Hashing function and equality for constraint entries. */
25380 {
25382 {
25384 }
25387 {
25392 }
25393 };
25398 /* Search for a memoized satisfaction result. Returns one of the
25399 truth value nodes if previously memoized, or NULL_TREE otherwise. */
25401 tree
25403 {
25408 else
25410 }
25412 /* Memoize the result of a satisfication test. Returns the saved result. */
25414 tree
25416 {
25423 }
25425 /* Search for a memoized satisfaction result for a concept. */
25427 tree
25429 {
25434 else
25436 }
25438 /* Memoize the result of a concept check. Returns the saved result. */
25440 tree
25442 {
25449 }
25453 /* Returns a prior concept specialization. This returns the substituted
25454 and normalized constraints defined by the concept. */
25456 tree
25458 {
25463 else
25465 }
25467 /* Save a concept expansion for later. */
25469 tree
25471 {
25478 }
25480 static hashval_t
25482 {
25491 }
25493 /* Compare the constraints of two subsumption entries. The LEFT1 and
25494 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
25495 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
25497 static bool
25499 {
25507 }
25509 /* Key/value pair for learning and memoizing subsumption results. This
25510 associates a pair of check constraints (including arguments) with
25511 a boolean value indicating the result. */
25514 {
25515 tree t1;
25516 tree t2;
25518 };
25520 /* Hashing function and equality for constraint entries. */
25523 {
25525 {
25527 }
25530 {
25535 }
25536 };
25540 /* Search for a previously cached subsumption result. */
25544 {
25549 else
25551 }
25553 /* Save a subsumption result. */
25555 bool
25557 {
25564 }
25566 /* Set up the hash table for constraint association. */
25568 void
25570 {
25579 }
25581 /* Set up the hash tables for template instantiations. */
25583 void
25585 {
25588 }
25590 /* Print stats about the template hash tables for -fstats. */
25592 void
25594 {
25603 }