| blob | 252712e80f240bbd37e72668f68aa7383e9b4648 |
1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2017 Free Software Foundation, Inc.
3 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
4 Rewritten by Jason Merrill (jason@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Known bugs or deficiencies include:
24 all methods must be provided in header files; can't use a source
25 file that contains only the method templates and "just win". */
45 /* The type of functions taking a tree, and some additional data, and
46 returning an int. */
49 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
50 instantiations have been deferred, either because their definitions
51 were not yet available, or because we were putting off doing the work. */
55 };
70 /* Live only within one (recursive) call to tsubst_expr. We use
71 this to pass the statement expression node from the STMT_EXPR
72 to the EXPR_STMT that is its result. */
75 // -------------------------------------------------------------------------- //
76 // Local Specialization Stack
77 //
78 // Implementation of the RAII helper for creating new local
79 // specializations.
82 {
85 else
87 }
90 {
93 }
95 /* True if we've recursed into fn_type_unification too many times. */
99 {
100 tree tmpl;
101 tree args;
102 tree spec;
103 };
106 {
109 };
115 /* Contains canonical template parameter types. The vector is indexed by
116 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
117 TREE_LIST, whose TREE_VALUEs contain the canonical template
118 parameters of various types and levels. */
121 #define UNIFY_ALLOW_NONE 0
122 #define UNIFY_ALLOW_MORE_CV_QUAL 1
123 #define UNIFY_ALLOW_LESS_CV_QUAL 2
124 #define UNIFY_ALLOW_DERIVED 4
125 #define UNIFY_ALLOW_INTEGER 8
126 #define UNIFY_ALLOW_OUTER_LEVEL 16
127 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
128 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
131 tbr_incomplete_type,
132 tbr_ambiguous_baseclass,
133 tbr_success
134 };
157 tree);
214 location_t);
225 /* Make the current scope suitable for access checking when we are
226 processing T. T can be FUNCTION_DECL for instantiated function
227 template, VAR_DECL for static member variable, or TYPE_DECL for
228 alias template (needed by instantiate_decl). */
230 static void
232 {
240 else
244 {
245 saved_access_scope = tree_cons
248 }
249 }
251 /* Restore the scope set up by push_access_scope. T is the node we
252 are processing. */
254 static void
256 {
258 {
261 }
265 else
267 }
269 /* Do any processing required when DECL (a member template
270 declaration) is finished. Returns the TEMPLATE_DECL corresponding
271 to DECL, unless it is a specialization, in which case the DECL
272 itself is returned. */
274 tree
276 {
283 {
284 tree type;
292 {
296 }
298 }
302 {
304 {
307 }
308 else
310 }
311 else
315 }
317 /* Create a template info node. */
319 tree
321 {
326 }
328 /* Return the template info node corresponding to T, whatever T is. */
330 tree
332 {
354 }
356 /* Returns the template nesting level of the indicated class TYPE.
358 For example, in:
359 template <class T>
360 struct A
361 {
362 template <class U>
363 struct B {};
364 };
366 A<T>::B<U> has depth two, while A<T> has depth one.
367 Both A<T>::B<int> and A<int>::B<U> have depth one, if
368 they are instantiations, not specializations.
370 This function is guaranteed to return 0 if passed NULL_TREE so
371 that, for example, `template_class_depth (current_class_type)' is
372 always safe. */
374 int
376 {
380 {
391 else
393 }
396 }
398 /* Subroutine of maybe_begin_member_template_processing.
399 Returns true if processing DECL needs us to push template parms. */
401 static bool
403 {
409 }
411 /* Subroutine of maybe_begin_member_template_processing.
412 Push the template parms in PARMS, starting from LEVELS steps into the
413 chain, and ending at the beginning, since template parms are listed
414 innermost first. */
416 static void
418 {
426 current_template_parms
432 NULL);
434 {
443 {
450 /* Push the CONST_DECL. */
456 }
457 }
458 }
460 /* Restore the template parameter context for a member template, a
461 friend template defined in a class definition, or a non-template
462 member of template class. */
464 void
466 {
467 tree parms;
472 {
475 /* Disregard full specializations (c++/60999). */
478 }
481 {
486 {
489 }
492 }
494 /* Remember how many levels of template parameters we pushed so that
495 we can pop them later. */
497 }
499 /* Undo the effects of maybe_begin_member_template_processing. */
501 void
503 {
512 {
516 }
517 }
519 /* Return a new template argument vector which contains all of ARGS,
520 but has as its innermost set of arguments the EXTRA_ARGS. */
522 static tree
524 {
525 tree new_args;
543 }
545 /* Like add_to_template_args, but only the outermost ARGS are added to
546 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
547 (EXTRA_ARGS) levels are added. This function is used to combine
548 the template arguments from a partial instantiation with the
549 template arguments used to attain the full instantiation from the
550 partial instantiation. */
552 static tree
554 {
555 tree new_args;
557 /* If there are more levels of EXTRA_ARGS than there are ARGS,
558 something very fishy is going on. */
561 /* If *all* the new arguments will be the EXTRA_ARGS, just return
562 them. */
566 /* For the moment, we make ARGS look like it contains fewer levels. */
571 /* Now, we restore ARGS to its full dimensions. */
575 }
577 /* Return the N levels of innermost template arguments from the ARGS. */
579 tree
581 {
582 tree new_args;
588 /* If N is 1, just return the innermost set of template arguments. */
592 /* If we're not removing anything, just return the arguments we were
593 given. */
599 /* Make a new set of arguments, not containing the outer arguments. */
606 }
608 /* The inverse of get_innermost_template_args: Return all but the innermost
609 EXTRA_LEVELS levels of template arguments from the ARGS. */
611 static tree
613 {
614 tree new_args;
620 /* If N is 1, just return the outermost set of template arguments. */
624 /* If we're not removing anything, just return the arguments we were
625 given. */
630 /* Make a new set of arguments, not containing the inner arguments. */
637 }
639 /* We've got a template header coming up; push to a new level for storing
640 the parms. */
642 void
644 {
645 /* We use a non-tag-transparent scope here, which causes pushtag to
646 put tags in this scope, rather than in the enclosing class or
647 namespace scope. This is the right thing, since we want
648 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
649 global template class, push_template_decl handles putting the
650 TEMPLATE_DECL into top-level scope. For a nested template class,
651 e.g.:
653 template <class T> struct S1 {
654 template <class T> struct S2 {};
655 };
657 pushtag contains special code to insert the TEMPLATE_DECL for S2
658 at the right scope. */
664 /* Add a dummy parameter level while we process the parameter list. */
665 current_template_parms
668 current_template_parms);
669 }
671 /* This routine is called when a specialization is declared. If it is
672 invalid to declare a specialization here, an error is reported and
673 false is returned, otherwise this routine will return true. */
675 static bool
677 {
680 /* [temp.expl.spec]
682 An explicit specialization shall be declared in the namespace of
683 which the template is a member, or, for member templates, in the
684 namespace of which the enclosing class or enclosing class
685 template is a member. An explicit specialization of a member
686 function, member class or static data member of a class template
687 shall be declared in the namespace of which the class template
688 is a member. */
690 {
693 }
695 /* [temp.expl.spec]
697 In an explicit specialization declaration for a member of a class
698 template or a member template that appears in namespace scope,
699 the member template and some of its enclosing class templates may
700 remain unspecialized, except that the declaration shall not
701 explicitly specialize a class member template if its enclosing
702 class templates are not explicitly specialized as well. */
704 {
707 }
710 }
712 /* We've just seen template <>. */
714 bool
716 {
720 }
722 /* Called at then end of processing a declaration preceded by
723 template<>. */
725 void
727 {
730 }
732 /* Any template <>'s that we have seen thus far are not referring to a
733 function specialization. */
735 void
737 {
740 }
742 /* We've just seen a template header. If SPECIALIZATION is nonzero,
743 it was of the form template <>. */
745 static void
747 {
749 template_header_count++;
750 }
752 /* We're beginning an explicit instantiation. */
754 void
756 {
759 }
762 void
764 {
767 }
769 /* An explicit specialization or partial specialization of TMPL is being
770 declared. Check that the namespace in which the specialization is
771 occurring is permissible. Returns false iff it is invalid to
772 specialize TMPL in the current namespace. */
774 static bool
776 {
779 /* [tmpl.expl.spec]
781 An explicit specialization shall be declared in a namespace enclosing the
782 specialized template. An explicit specialization whose declarator-id is
783 not qualified shall be declared in the nearest enclosing namespace of the
784 template, or, if the namespace is inline (7.3.1), any namespace from its
785 enclosing namespace set. */
788 {
791 }
794 /* Same or enclosing namespace. */
796 else
797 {
803 }
804 }
806 /* SPEC is an explicit instantiation. Check that it is valid to
807 perform this explicit instantiation in the current namespace. */
809 static void
811 {
812 tree ns;
814 /* DR 275: An explicit instantiation shall appear in an enclosing
815 namespace of its template. */
821 }
823 // Returns the type of a template specialization only if that
824 // specialization needs to be defined. Otherwise (e.g., if the type has
825 // already been defined), the function returns NULL_TREE.
826 static tree
828 {
829 // An implicit instantiation of an incomplete type implies
830 // the definition of a new class template.
831 //
832 // template<typename T>
833 // struct S;
834 //
835 // template<typename T>
836 // struct S<T*>;
837 //
838 // Here, S<T*> is an implicit instantiation of S whose type
839 // is incomplete.
843 // It can also be the case that TYPE is a completed specialization.
844 // Continuing the previous example, suppose we also declare:
845 //
846 // template<typename T>
847 // requires Integral<T>
848 // struct S<T*>;
849 //
850 // Here, S<T*> refers to the specialization S<T*> defined
851 // above. However, we need to differentiate definitions because
852 // we intend to define a new partial specialization. In this case,
853 // we rely on the fact that the constraints are different for
854 // this declaration than that above.
855 //
856 // Note that we also get here for injected class names and
857 // late-parsed template definitions. We must ensure that we
858 // do not create new type declarations for those cases.
860 {
864 // If there are no template parameters, this cannot be a new
865 // partial template specializtion?
869 // The injected-class-name is not a new partial specialization.
873 // If the constraints are not the same as those of the primary
874 // then, we can probably create a new specialization.
878 {
882 }
884 // Also, if there's a pre-existing specialization with matching
885 // constraints, then this also isn't new.
888 {
896 }
898 // Create a new type node (and corresponding type decl)
899 // for the newly declared specialization.
904 /* We only need a separate type node for storing the definition of this
905 partial specialization; uses of S<T*> are unconstrained, so all are
906 equivalent. So keep TYPE_CANONICAL the same. */
909 // Build the corresponding type decl.
915 }
918 }
920 /* The TYPE is being declared. If it is a template type, that means it
921 is a partial specialization. Do appropriate error-checking. */
923 tree
925 {
926 tree context;
931 /* A lambda that appears in specialization context is not itself a
932 specialization. */
937 {
941 }
946 {
952 else
955 }
957 {
958 /* This is for ordinary explicit specialization and partial
959 specialization of a template class such as:
961 template <> class C<int>;
963 or:
965 template <class T> class C<T*>;
967 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
970 {
977 {
982 }
983 }
989 /* Trying to define a specialization either without a template<> header
990 or in an inappropriate place. We've already given an error, so just
991 bail now so we don't actually define the specialization. */
993 }
999 {
1000 /* This is for an explicit specialization of member class
1001 template according to [temp.expl.spec/18]:
1003 template <> template <class U> class C<int>::D;
1005 The context `C<int>' must be an implicit instantiation.
1006 Otherwise this is just a member class template declared
1007 earlier like:
1009 template <> class C<int> { template <class U> class D; };
1010 template <> template <class U> class C<int>::D;
1012 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1013 while in the second case, `C<int>::D' is a primary template
1014 and `C<T>::D' may not exist. */
1018 {
1019 tree t;
1024 {
1029 }
1031 /* Check for invalid specialization after instantiation:
1033 template <> template <> class C<int>::D<int>;
1034 template <> template <class U> class C<int>::D; */
1038 {
1042 {
1043 /* We already have a full specialization of this partial
1044 instantiation, or a full specialization has been
1045 looked up but not instantiated. Reassign it to the
1046 new member specialization template. */
1047 spec_entry elt;
1059 spec_entry **slot
1064 }
1065 else
1066 /* But if we've had an implicit instantiation, that's a
1067 problem ([temp.expl.spec]/6). */
1070 }
1072 /* Mark TYPE as a specialization. And as a result, we only
1073 have one level of template argument for the innermost
1074 class template. */
1079 }
1080 }
1082 {
1083 /* Someday C++0x may allow for enum template specialization. */
1088 else
1089 {
1092 }
1093 }
1096 }
1098 /* Returns nonzero if we can optimize the retrieval of specializations
1099 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1100 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1104 {
1107 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1108 parameter. */
1110 /* The optimized lookup depends on the fact that the
1111 template arguments for the member function template apply
1112 purely to the containing class, which is not true if the
1113 containing class is an explicit or partial
1114 specialization. */
1118 /* It is possible to have a template that is not a member
1119 template and is not a member of a template class:
1121 template <typename T>
1122 struct S { friend A::f(); };
1124 Here, the friend function is a template, but the context does
1125 not have template information. The optimized lookup relies
1126 on having ARGS be the template arguments for both the class
1127 and the function template. */
1129 }
1131 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1132 gone through coerce_template_parms by now. */
1134 static void
1136 {
1139 {
1142 {
1149 /* Allow typedefs on the type of a non-type argument, since a
1151 else
1153 }
1154 }
1156 }
1158 /* Retrieve the specialization (in the sense of [temp.spec] - a
1159 specialization is either an instantiation or an explicit
1160 specialization) of TMPL for the given template ARGS. If there is
1161 no such specialization, return NULL_TREE. The ARGS are a vector of
1162 arguments, or a vector of vectors of arguments, in the case of
1163 templates with more than one level of parameters.
1165 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1166 then we search for a partial specialization matching ARGS. This
1167 parameter is ignored if TMPL is not a class template.
1169 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1170 result is a NONTYPE_ARGUMENT_PACK. */
1172 static tree
1174 {
1184 /* There should be as many levels of arguments as there are
1185 levels of parameters. */
1194 /* Lambda functions in templates aren't instantiated normally, but through
1195 tsubst_lambda_expr. */
1200 {
1201 /* The template arguments actually apply to the containing
1202 class. Find the class specialization with those
1203 arguments. */
1205 tree class_specialization
1210 /* Find the instance of TMPL. */
1213 {
1216 /* using-declarations can add base methods to the method vec,
1217 and we don't want those here. */
1220 }
1222 }
1223 else
1224 {
1226 spec_entry elt;
1235 else
1243 }
1246 }
1248 /* Like retrieve_specialization, but for local declarations. */
1250 tree
1252 {
1258 }
1260 /* Returns nonzero iff DECL is a specialization of TMPL. */
1262 int
1264 {
1265 tree t;
1268 {
1274 }
1275 else
1276 {
1285 }
1288 }
1290 /* Returns nonzero iff DECL is a specialization of friend declaration
1291 FRIEND_DECL according to [temp.friend]. */
1293 bool
1295 {
1302 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1303 of a template class, we want to check if DECL is a specialization
1304 if this. */
1308 {
1309 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1312 }
1317 /* There is nothing to do if this is not a template friend. */
1324 /* [temp.friend/6]
1325 A member of a class template may be declared to be a friend of a
1326 non-template class. In this case, the corresponding member of
1327 every specialization of the class template is a friend of the
1328 class granting friendship.
1330 For example, given a template friend declaration
1332 template <class T> friend void A<T>::f();
1334 the member function below is considered a friend
1336 template <> struct A<int> {
1337 void f();
1338 };
1340 For this type of template friend, TEMPLATE_DEPTH below will be
1341 nonzero. To determine if DECL is a friend of FRIEND, we first
1342 check if the enclosing class is a specialization of another. */
1349 {
1350 /* Next, we check the members themselves. In order to handle
1351 a few tricky cases, such as when FRIEND_DECL's are
1353 template <class T> friend void A<T>::g(T t);
1354 template <class T> template <T t> friend void A<T>::h();
1356 and DECL's are
1358 void A<int>::g(int);
1359 template <int> void A<int>::h();
1361 we need to figure out ARGS, the template arguments from
1362 the context of DECL. This is required for template substitution
1363 of `T' in the function parameter of `g' and template parameter
1364 of `h' in the above examples. Here ARGS corresponds to `int'. */
1371 {
1373 {
1376 else
1378 current_depth++;
1379 }
1381 }
1384 {
1386 tree friend_type;
1387 tree decl_type;
1388 tree friend_args_type;
1389 tree decl_args_type;
1391 /* Make sure that both DECL and FRIEND_DECL are templates or
1392 non-templates. */
1398 {
1399 /* If both are templates, check template parameter list. */
1400 tree friend_parms
1405 friend_parms))
1409 }
1410 else
1418 /* Check if return types match. */
1422 /* Check if function parameter types match, ignoring the
1423 `this' parameter. */
1432 }
1433 else
1434 {
1435 /* DECL is a TYPE_DECL */
1439 /* Make sure that both DECL and FRIEND_DECL are templates or
1440 non-templates. */
1441 is_template
1448 {
1449 tree friend_parms;
1450 /* If both are templates, check the name of the two
1451 TEMPLATE_DECL's first because is_friend didn't. */
1456 /* Now check template parameter list. */
1457 friend_parms
1460 return comp_template_parms
1462 friend_parms);
1463 }
1464 else
1467 }
1468 }
1470 }
1472 /* Register the specialization SPEC as a specialization of TMPL with
1473 the indicated ARGS. IS_FRIEND indicates whether the specialization
1474 is actually just a friend declaration. Returns SPEC, or an
1475 equivalent prior declaration, if available.
1477 We also store instantiations of field packs in the hash table, even
1478 though they are not themselves templates, to make lookup easier. */
1480 static tree
1482 hashval_t hash)
1483 {
1484 tree fn;
1486 spec_entry elt;
1494 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1495 register it; we want the corresponding TEMPLATE_DECL instead.
1496 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1497 the more obvious `uses_template_parms (spec)' to avoid problems
1498 with default function arguments. In particular, given
1499 something like this:
1501 template <class T> void f(T t1, T t = T())
1503 the default argument expression is not substituted for in an
1504 instantiation unless and until it is actually needed. */
1508 /* We don't put these specializations in the hash table, but we might
1509 want to give an error about a mismatch. */
1511 else
1512 {
1520 slot =
1524 else
1526 }
1528 /* We can sometimes try to re-register a specialization that we've
1529 already got. In particular, regenerate_decl_from_template calls
1530 duplicate_decls which will update the specialization list. But,
1531 we'll still get called again here anyhow. It's more convenient
1532 to simply allow this than to try to prevent it. */
1536 {
1538 {
1541 {
1543 fn);
1545 }
1546 else
1547 {
1548 tree clone;
1549 /* This situation should occur only if the first
1550 specialization is an implicit instantiation, the
1551 second is an explicit specialization, and the
1552 implicit instantiation has not yet been used. That
1553 situation can occur if we have implicitly
1554 instantiated a member function and then specialized
1555 it later.
1557 We can also wind up here if a friend declaration that
1558 looked like an instantiation turns out to be a
1559 specialization:
1561 template <class T> void foo(T);
1562 class S { friend void foo<>(int) };
1563 template <> void foo(int);
1565 We transform the existing DECL in place so that any
1566 pointers to it become pointers to the updated
1567 declaration.
1569 If there was a definition for the template, but not
1570 for the specialization, we want this to look as if
1571 there were no definition, and vice versa. */
1574 /* The call to duplicate_decls will have applied
1575 [temp.expl.spec]:
1577 An explicit specialization of a function template
1578 is inline only if it is explicitly declared to be,
1579 and independently of whether its function template
1580 is.
1582 to the primary function; now copy the inline bits to
1583 the various clones. */
1585 {
1592 }
1596 }
1597 }
1599 {
1602 /* We've already complained in duplicate_decls. */
1606 /* Dup decl failed, but this is a new definition. Set the
1607 line number so any errors match this new
1608 definition. */
1612 }
1613 }
1617 /* A specialization must be declared in the same namespace as the
1618 template it is specializing. */
1624 {
1633 /* If TMPL is a forward declaration of a template function, keep a list
1634 of all specializations in case we need to reassign them to a friend
1635 template later in tsubst_friend_function.
1637 Also keep a list of all variable template instantiations so that
1638 process_partial_specialization can check whether a later partial
1639 specialization would have used it. */
1642 }
1645 }
1647 /* Returns true iff two spec_entry nodes are equivalent. */
1651 bool
1653 {
1660 /* tmpl could be a FIELD_DECL for a capture pack. */
1664 {
1665 /* Partial specializations of a variable template can be distinguished by
1666 constraints. */
1670 }
1674 }
1676 /* Returns a hash for a template TMPL and template arguments ARGS. */
1678 static hashval_t
1680 {
1683 }
1685 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1686 ignoring SPEC. */
1688 hashval_t
1690 {
1692 }
1694 /* Recursively calculate a hash value for a template argument ARG, for use
1695 in the hash tables of template specializations. */
1697 hashval_t
1699 {
1719 {
1727 {
1732 }
1754 {
1758 {
1761 }
1763 }
1767 {
1770 }
1781 val = iterative_hash_template_arg
1793 val);
1795 val);
1804 /* A lambda can't appear in a template arg, but don't crash on
1805 erroneous input. */
1817 /* Now hash operands as usual. */
1822 }
1825 {
1828 {
1829 // We want an alias specialization that survived strip_typedefs
1830 // to hash differently from its TYPE_CANONICAL, to avoid hash
1831 // collisions that compare as different in template_args_equal.
1832 // These could be dependent specializations that strip_typedefs
1833 // left alone, or untouched specializations because
1834 // coerce_template_parms returns the unconverted template
1835 // arguments if it sees incomplete argument packs.
1838 }
1841 val);
1844 /* Otherwise just compare the types during lookup. */
1853 {
1858 }
1859 }
1862 }
1864 /* Unregister the specialization SPEC as a specialization of TMPL.
1865 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1866 if the SPEC was listed as a specialization of TMPL.
1868 Note that SPEC has been ggc_freed, so we can't look inside it. */
1870 bool
1872 {
1874 spec_entry elt;
1882 {
1887 }
1890 }
1892 /* Like register_specialization, but for local declarations. We are
1893 registering SPEC, an instantiation of TMPL. */
1895 void
1897 {
1900 }
1902 /* TYPE is a class type. Returns true if TYPE is an explicitly
1903 specialized class. */
1905 bool
1907 {
1911 }
1913 /* Print the list of functions at FNS, going through all the overloads
1914 for each element of the list. Alternatively, FNS can not be a
1915 TREE_LIST, in which case it will be printed together with all the
1916 overloads.
1918 MORE and *STR should respectively be FALSE and NULL when the function
1919 is called from the outside. They are used internally on recursive
1920 calls. print_candidates manages the two parameters and leaves NULL
1921 in *STR when it ends. */
1923 static void
1925 {
1929 else
1931 {
1937 {
1940 else
1943 }
1945 }
1946 }
1948 /* Print the list of candidate FNS in an error message. FNS can also
1949 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1951 void
1953 {
1957 }
1959 /* Get a (possibly) constrained template declaration for the
1960 purpose of ordering candidates. */
1961 static tree
1963 {
1969 }
1971 /* Among candidates having the same signature, return the
1972 most constrained or NULL_TREE if there is no best candidate.
1973 If the signatures of candidates vary (e.g., template
1974 specialization vs. member function), then there can be no
1975 most constrained.
1977 Note that we don't compare constraints on the functions
1978 themselves, but rather those of their templates. */
1979 static tree
1981 {
1982 // Try to find the best candidate in a first pass.
1985 {
1992 }
1994 // Verify that the champ is better than previous candidates.
1999 }
2002 }
2005 /* Returns the template (one of the functions given by TEMPLATE_ID)
2006 which can be specialized to match the indicated DECL with the
2007 explicit template args given in TEMPLATE_ID. The DECL may be
2008 NULL_TREE if none is available. In that case, the functions in
2009 TEMPLATE_ID are non-members.
2011 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2012 specialization of a member template.
2014 The TEMPLATE_COUNT is the number of references to qualifying
2015 template classes that appeared in the name of the function. See
2016 check_explicit_specialization for a more accurate description.
2018 TSK indicates what kind of template declaration (if any) is being
2019 declared. TSK_TEMPLATE indicates that the declaration given by
2020 DECL, though a FUNCTION_DECL, has template parameters, and is
2021 therefore a template function.
2023 The template args (those explicitly specified and those deduced)
2024 are output in a newly created vector *TARGS_OUT.
2026 If it is impossible to determine the result, an error message is
2027 issued. The error_mark_node is returned to indicate failure. */
2029 static tree
2031 tree decl,
2035 tmpl_spec_kind tsk)
2036 {
2037 tree fns;
2038 tree targs;
2039 tree explicit_targs;
2042 /* A TREE_LIST of templates of which DECL may be a specialization.
2043 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2044 corresponding TREE_PURPOSE is the set of template arguments that,
2045 when used to instantiate the template, would produce a function
2046 with the signature of DECL. */
2056 /* We shouldn't be specializing a member template of an
2057 unspecialized class template; we already gave an error in
2058 check_specialization_scope, now avoid crashing. */
2061 {
2064 }
2072 /* Check for baselinks. */
2077 {
2080 }
2082 {
2085 }
2087 /* Count the number of template headers specified for this
2088 specialization. */
2098 {
2101 tf_warning_or_error,
2105 }
2107 {
2111 {
2112 tree decl_arg_types;
2113 tree fn_arg_types;
2114 tree insttype;
2116 /* In case of explicit specialization, we need to check if
2117 the number of template headers appearing in the specialization
2118 is correct. This is usually done in check_explicit_specialization,
2119 but the check done there cannot be exhaustive when specializing
2120 member functions. Consider the following code:
2122 template <> void A<int>::f(int);
2123 template <> template <> void A<int>::f(int);
2125 Assuming that A<int> is not itself an explicit specialization
2126 already, the first line specializes "f" which is a non-template
2127 member function, whilst the second line specializes "f" which
2128 is a template member function. So both lines are syntactically
2129 correct, and check_explicit_specialization does not reject
2130 them.
2132 Here, we can do better, as we are matching the specialization
2133 against the declarations. We count the number of template
2134 headers, and we check if they match TEMPLATE_COUNT + 1
2135 (TEMPLATE_COUNT is the number of qualifying template classes,
2136 plus there must be another header for the member template
2137 itself).
2139 Notice that if header_count is zero, this is not a
2140 specialization but rather a template instantiation, so there
2141 is no check we can perform here. */
2145 /* Check that the number of template arguments at the
2146 innermost level for DECL is the same as for FN. */
2154 /* DECL might be a specialization of FN. */
2158 /* For a non-static member function, we need to make sure
2159 that the const qualification is the same. Since
2160 get_bindings does not try to merge the "this" parameter,
2161 we must do the comparison explicitly. */
2167 /* Skip the "this" parameter and, for constructors of
2168 classes with virtual bases, the VTT parameter. A
2169 full specialization of a constructor will have a VTT
2170 parameter, but a template never will. */
2171 decl_arg_types
2173 fn_arg_types
2176 /* Function templates cannot be specializations; there are
2177 no partial specializations of functions. Therefore, if
2178 the type of DECL does not match FN, there is no
2179 match.
2181 Note that it should never be the case that we have both
2182 candidates added here, and for regular member functions
2183 below. */
2185 {
2189 }
2191 /* See whether this function might be a specialization of this
2192 template. Suppress access control because we might be trying
2193 to make this specialization a friend, and we have already done
2194 access control for the declaration of the specialization. */
2200 /* We cannot deduce template arguments that when used to
2201 specialize TMPL will produce DECL. */
2204 /* Remove, from the set of candidates, all those functions
2205 whose constraints are not satisfied. */
2209 // Then, try to form the new function type.
2213 fn_arg_types
2218 /* Save this template, and the arguments deduced. */
2220 }
2222 /* FN is an ordinary member function, and we need a
2223 specialization of a member template. */
2224 ;
2226 /* We can get IDENTIFIER_NODEs here in certain erroneous
2227 cases. */
2228 ;
2230 /* This is just an ordinary non-member function. Nothing can
2231 be a specialization of that. */
2232 ;
2234 /* Cannot specialize functions that are created implicitly. */
2235 ;
2236 else
2237 {
2238 tree decl_arg_types;
2240 /* This is an ordinary member function. However, since
2241 we're here, we can assume its enclosing class is a
2242 template class. For example,
2244 template <typename T> struct S { void f(); };
2245 template <> void S<int>::f() {}
2247 Here, S<int>::f is a non-template, but S<int> is a
2248 template class. If FN has the same type as DECL, we
2249 might be in business. */
2252 /* Its enclosing class is an explicit specialization
2253 of a template class. This is not a candidate. */
2258 /* The return types differ. */
2261 /* Adjust the type of DECL in case FN is a static member. */
2268 decl_arg_types))
2271 // If the deduced arguments do not satisfy the constraints,
2272 // this is not a candidate.
2276 // Add the candidate.
2278 }
2279 }
2282 {
2283 /* We have:
2285 [temp.expl.spec]
2287 It is possible for a specialization with a given function
2288 signature to be instantiated from more than one function
2289 template. In such cases, explicit specification of the
2290 template arguments must be used to uniquely identify the
2291 function template specialization being specialized.
2293 Note that here, there's no suggestion that we're supposed to
2294 determine which of the candidate templates is most
2295 specialized. However, we, also have:
2297 [temp.func.order]
2299 Partial ordering of overloaded function template
2300 declarations is used in the following contexts to select
2301 the function template to which a function template
2302 specialization refers:
2304 -- when an explicit specialization refers to a function
2305 template.
2307 So, we do use the partial ordering rules, at least for now.
2308 This extension can only serve to make invalid programs valid,
2309 so it's safe. And, there is strong anecdotal evidence that
2310 the committee intended the partial ordering rules to apply;
2311 the EDG front end has that behavior, and John Spicer claims
2312 that the committee simply forgot to delete the wording in
2313 [temp.expl.spec]. */
2316 {
2319 }
2320 }
2322 // Concepts allows multiple declarations of member functions
2323 // with the same signature. Like above, we need to rely on
2324 // on the partial ordering of those candidates to determine which
2325 // is the best.
2327 {
2329 {
2332 }
2333 }
2336 {
2343 else
2346 }
2350 {
2356 }
2358 /* We have one, and exactly one, match. */
2360 {
2364 // Propagate the candidate's constraints to the declaration.
2367 /* DECL is a re-declaration or partial instantiation of a template
2368 function. */
2371 /* It was a specialization of an ordinary member function in a
2372 template class. */
2374 }
2376 /* It was a specialization of a template. */
2379 {
2384 }
2385 else
2388 }
2390 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2391 but with the default argument values filled in from those in the
2392 TMPL_TYPES. */
2394 static tree
2396 tree tmpl_types)
2397 {
2398 tree new_spec_types;
2406 /* Substitute into the rest of the list. */
2407 new_spec_types =
2411 /* Add the default argument for this parameter. */
2414 new_spec_types);
2415 }
2417 /* DECL is an explicit specialization. Replicate default arguments
2418 from the template it specializes. (That way, code like:
2420 template <class T> void f(T = 3);
2421 template <> void f(double);
2422 void g () { f (); }
2424 works, as required.) An alternative approach would be to look up
2425 the correct default arguments at the call-site, but this approach
2426 is consistent with how implicit instantiations are handled. */
2428 static void
2430 {
2431 tree tmpl;
2432 tree spec_types;
2433 tree tmpl_types;
2434 tree new_spec_types;
2435 tree old_type;
2436 tree new_type;
2437 tree t;
2442 /* See if there's anything we need to do. */
2455 {
2456 /* Remove the this pointer, but remember the object's type for
2457 CV quals. */
2463 {
2464 /* DECL may contain more parameters than TMPL due to the extra
2465 in-charge parameter in constructors and destructors. */
2468 }
2470 {
2473 }
2474 }
2476 /* Compute the merged default arguments. */
2477 new_spec_types =
2480 /* Compute the new FUNCTION_TYPE. */
2482 {
2486 new_spec_types);
2489 /* Put the in-charge parameter back. */
2492 new_spec_types);
2496 new_spec_types);
2497 }
2498 else
2500 new_spec_types);
2510 }
2512 /* Return the number of template headers we expect to see for a definition
2513 or specialization of CTYPE or one of its non-template members. */
2515 int
2517 {
2521 {
2522 /* You're supposed to have one `template <...>' for every
2523 template class, but you don't need one for a full
2524 specialization. For example:
2526 template <class T> struct S{};
2527 template <> struct S<int> { void f(); };
2528 void S<int>::f () {}
2530 is correct; there shouldn't be a `template <>' for the
2531 definition of `S<int>::f'. */
2533 /* If CTYPE does not have template information of any
2534 kind, then it is not a template, nor is it nested
2535 within a template. */
2543 }
2546 }
2548 /* Do a simple sanity check on the template headers that precede the
2549 variable declaration DECL. */
2551 void
2553 {
2558 {
2561 "variable templates only available with "
2564 // Namespace-scope variable templates should have a template header.
2566 }
2568 {
2570 "too many template headers for %qD "
2576 "members of an explicitly specialized class are defined "
2578 }
2579 }
2581 /* An explicit specialization whose declarator-id or class-head-name is not
2582 qualified shall be declared in the nearest enclosing namespace of the
2583 template, or, if the namespace is inline (7.3.1), any namespace from its
2584 enclosing namespace set.
2586 If the name declared in the explicit instantiation is an unqualified name,
2587 the explicit instantiation shall appear in the namespace where its template
2588 is declared or, if that namespace is inline (7.3.1), any namespace from its
2589 enclosing namespace set. */
2591 void
2593 {
2598 {
2604 /* This was allowed in C++98, so only pedwarn. */
2606 "outside its namespace must use a nested-name-"
2608 }
2609 }
2611 /* Check to see if the function just declared, as indicated in
2612 DECLARATOR, and in DECL, is a specialization of a function
2613 template. We may also discover that the declaration is an explicit
2614 instantiation at this point.
2616 Returns DECL, or an equivalent declaration that should be used
2617 instead if all goes well. Issues an error message if something is
2618 amiss. Returns error_mark_node if the error is not easily
2619 recoverable.
2621 FLAGS is a bitmask consisting of the following flags:
2623 2: The function has a definition.
2624 4: The function is a friend.
2626 The TEMPLATE_COUNT is the number of references to qualifying
2627 template classes that appeared in the name of the function. For
2628 example, in
2630 template <class T> struct S { void f(); };
2631 void S<int>::f();
2633 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2634 classes are not counted in the TEMPLATE_COUNT, so that in
2636 template <class T> struct S {};
2637 template <> struct S<int> { void f(); }
2638 template <> void S<int>::f();
2640 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2641 invalid; there should be no template <>.)
2643 If the function is a specialization, it is marked as such via
2644 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2645 is set up correctly, and it is added to the list of specializations
2646 for that template. */
2648 tree
2650 tree decl,
2653 {
2662 tmpl_spec_kind tsk;
2665 {
2668 else
2670 }
2671 else
2675 {
2678 {
2681 }
2683 {
2685 /* This could be something like:
2687 template <class T> void f(T);
2688 class S { friend void f<>(int); } */
2690 else
2691 {
2692 /* This case handles bogus declarations like template <>
2693 template <class T> void f<int>(); */
2696 declarator);
2698 }
2699 }
2703 /* The error has already been reported in
2704 check_specialization_scope. */
2710 /* Fall through. */
2723 decl);
2726 else
2730 /* Fall through. */
2736 /* In cases like template<> constexpr bool v = true;
2737 We'll give an error in check_template_variable. */
2743 else
2749 {
2750 /* This case handles bogus declarations like template <>
2751 template <class T> void f<int>(); */
2755 declarator);
2757 {
2758 /* Partial specialization of variable template. */
2762 }
2766 else
2770 ok:;
2771 }
2774 /* This is a specialization of a member template, without
2775 specialization the containing class. Something like:
2777 template <class T> struct S {
2778 template <class U> void f (U);
2779 };
2780 template <> template <class U> void S<int>::f(U) {}
2782 That's a specialization -- but of the entire template. */
2788 }
2791 /* This doesn't apply to variable templates. */
2794 {
2798 {
2802 }
2803 }
2806 {
2811 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2813 {
2814 tree fns;
2819 else
2820 {
2821 /* If there is no class context, the explicit instantiation
2822 must be at namespace scope. */
2825 /* Find the namespace binding, using the declaration
2826 context. */
2830 /* If lookup fails, look for a friend declaration so we can
2831 give a better diagnostic. */
2837 {
2840 }
2841 }
2844 }
2850 {
2852 /* A specialization in class scope. This is invalid,
2853 but the error will already have been flagged by
2854 check_specialization_scope. */
2856 else
2857 {
2858 /* It's not valid to write an explicit instantiation in
2859 class scope, e.g.:
2861 class C { template void f(); }
2863 This case is caught by the parser. However, on
2864 something like:
2866 template class C { void f(); };
2868 (which is invalid) we can get here. The error will be
2869 issued later. */
2870 ;
2871 }
2874 }
2877 {
2878 // We'll match variable templates in start_decl.
2882 /* Find the list of functions in ctype that have the same
2883 name as the declared function. */
2887 {
2891 {
2892 /* From [temp.expl.spec]:
2894 If such an explicit specialization for the member
2895 of a class template names an implicitly-declared
2896 special member function (clause _special_), the
2897 program is ill-formed.
2899 Similar language is found in [temp.explicit]. */
2902 }
2905 }
2907 /* For a type-conversion operator, We might be looking for
2908 `operator int' which will be a specialization of
2909 `operator T'. Grab all the conversion operators, and
2910 then select from them. */
2915 {
2918 }
2919 else
2921 }
2923 /* Figure out what exactly is being specialized at this point.
2924 Note that for an explicit instantiation, even one for a
2925 member function, we cannot tell a priori whether the
2926 instantiation is for a member template, or just a member
2927 function of a template class. Even if a member template is
2928 being instantiated, the member template arguments may be
2929 elided if they can be deduced from the rest of the
2930 declaration. */
2933 member_specialization,
2934 template_count,
2935 tsk);
2938 /* We couldn't figure out what this declaration was
2939 specializing. */
2941 else
2942 {
2945 {
2947 "friend declaration %qD is not visible to "
2951 }
2959 {
2960 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
2961 is done by do_decl_instantiation later. */
2967 {
2968 /* If TMPL is not the most general template (for
2969 example, if TMPL is a friend template that is
2970 injected into namespace scope), then there will
2971 be too many levels of TARGS. Remove some of them
2972 here. */
2974 tree new_targs;
2981 }
2984 }
2986 /* If we thought that the DECL was a member function, but it
2987 turns out to be specializing a static member function,
2988 make DECL a static member function as well. */
2994 /* If this is a specialization of a member template of a
2995 template class, we want to return the TEMPLATE_DECL, not
2996 the specialization of it. */
2998 {
3003 {
3004 tree parm;
3008 /* We want to use the argument list specified in the
3009 definition, not in the original declaration. */
3014 }
3017 }
3019 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3025 /* Inherit default function arguments from the template
3026 DECL is specializing. */
3030 /* This specialization has the same protection as the
3031 template it specializes. */
3035 /* 7.1.1-1 [dcl.stc]
3037 A storage-class-specifier shall not be specified in an
3038 explicit specialization...
3040 The parser rejects these, so unless action is taken here,
3041 explicit function specializations will always appear with
3042 global linkage.
3044 The action recommended by the C++ CWG in response to C++
3045 defect report 605 is to make the storage class and linkage
3046 of the explicit specialization match the templated function:
3048 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3049 */
3051 {
3055 /* A concept cannot be specialized. */
3057 {
3059 gen_tmpl);
3061 }
3063 /* This specialization has the same linkage and visibility as
3064 the function template it specializes. */
3067 {
3070 }
3073 {
3076 }
3077 }
3079 /* If DECL is a friend declaration, declared using an
3080 unqualified name, the namespace associated with DECL may
3081 have been set incorrectly. For example, in:
3083 template <typename T> void f(T);
3084 namespace N {
3085 struct S { friend void f<int>(int); }
3086 }
3088 we will have set the DECL_CONTEXT for the friend
3089 declaration to N, rather than to the global namespace. */
3094 /* This is not really a declaration of a specialization.
3095 It's just the name of an instantiation. But, it's not
3096 a request for an instantiation, either. */
3099 /* A specialization is not necessarily COMDAT. */
3105 /* If this is a full specialization, register it so that we can find
3106 it again. Partial specializations will be registered in
3107 process_partial_specialization. */
3112 /* A 'structor should already have clones. */
3118 }
3119 }
3122 }
3124 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3125 parameters. These are represented in the same format used for
3126 DECL_TEMPLATE_PARMS. */
3128 int
3130 {
3131 const_tree p1;
3132 const_tree p2;
3140 {
3152 {
3156 /* If either of the template parameters are invalid, assume
3157 they match for the sake of error recovery. */
3170 }
3171 }
3174 /* One set of parameters has more parameters lists than the
3175 other. */
3179 }
3181 /* Determine whether PARM is a parameter pack. */
3183 bool
3185 {
3186 /* Determine if we have a non-type template parameter pack. */
3193 /* If this is a list of template parameters, we could get a
3194 TYPE_DECL or a TEMPLATE_DECL. */
3198 /* Otherwise it must be a type template parameter. */
3202 }
3204 /* Determine if T is a function parameter pack. */
3206 bool
3208 {
3212 }
3214 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3215 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3217 tree
3219 {
3226 }
3228 /* Return true iff the function parameter PARAM_DECL was expanded
3229 from the function parameter pack PACK. */
3231 bool
3233 {
3238 /* The parameter pack and its pack arguments have the same
3239 DECL_PARM_INDEX. */
3241 }
3243 /* Determine whether ARGS describes a variadic template args list,
3244 i.e., one that is terminated by a template argument pack. */
3246 static bool
3248 {
3250 tree last_parm;
3264 }
3266 /* Generate a new name for the parameter pack name NAME (an
3267 IDENTIFIER_NODE) that incorporates its */
3269 static tree
3271 {
3272 /* Munge the name to include the parameter index. */
3273 #define NUMBUF_LEN 128
3287 }
3289 /* Return true if T is a primary function, class or alias template
3290 specialization, not including the template pattern. */
3292 bool
3294 {
3310 }
3312 /* Return true if PARM is a template template parameter. */
3314 bool
3316 {
3318 }
3320 /* Return true iff PARM is a DECL representing a type template
3321 parameter. */
3323 bool
3325 {
3330 }
3332 /* Return the template parameters of T if T is a
3333 primary template instantiation, NULL otherwise. */
3335 tree
3337 {
3342 parms = INNERMOST_TEMPLATE_PARMS
3346 }
3348 /* Return the template parameters of the LEVELth level from the full list
3349 of template parameters PARMS. */
3351 tree
3353 {
3354 tree p;
3365 }
3367 /* Returns the template arguments of T if T is a template instantiation,
3368 NULL otherwise. */
3370 tree
3372 {
3380 }
3382 /* Return the argument pack elements of T if T is a template argument pack,
3383 NULL otherwise. */
3385 tree
3387 {
3393 }
3395 /* True iff FN is a function representing a built-in variadic parameter
3396 pack. */
3398 bool
3400 {
3410 }
3412 /* True iff CALL is a call to a function representing a built-in variadic
3413 parameter pack. */
3415 static bool
3417 {
3421 }
3423 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3425 static tree
3427 tree in_decl)
3428 {
3434 {
3436 {
3439 }
3444 }
3445 else
3446 {
3450 /* Calculate the largest value of len that won't make the size of the vec
3451 overflow an int. The compiler will exceed resource limits long before
3452 this, but it seems a decent place to diagnose. */
3456 {
3461 }
3469 }
3470 }
3472 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3473 CALL. */
3475 static tree
3477 tree in_decl)
3478 {
3488 }
3490 /* Structure used to track the progress of find_parameter_packs_r. */
3491 struct find_parameter_pack_data
3492 {
3493 /* TREE_LIST that will contain all of the parameter packs found by
3494 the traversal. */
3497 /* Set of AST nodes that have been visited by the traversal. */
3500 /* True iff we're making a type pack expansion. */
3502 };
3504 /* Identifies all of the argument packs that occur in a template
3505 argument and appends them to the TREE_LIST inside DATA, which is a
3506 find_parameter_pack_data structure. This is a subroutine of
3507 make_pack_expansion and uses_parameter_packs. */
3508 static tree
3510 {
3516 /* Handle type aliases/typedefs. */
3518 {
3525 }
3527 /* Identify whether this is a parameter pack or not. */
3529 {
3537 /* FALLTHRU */
3539 /* If the placeholder appears in the decl-specifier-seq of a function
3540 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3541 is a pack expansion, the invented template parameter is a template
3542 parameter pack. */
3552 {
3553 /* We don't want to walk into the type of a PARM_DECL,
3554 because we don't want to see the type parameter pack. */
3557 }
3560 /* Look through a lambda capture proxy to the field pack. */
3563 {
3569 }
3571 {
3573 find_parameter_packs_r,
3576 }
3588 /* Not a parameter pack. */
3590 }
3593 {
3594 /* Add this parameter pack to the list. */
3596 }
3602 /* This switch statement will return immediately if we don't find a
3603 parameter pack. */
3605 {
3610 /* Check the template itself. */
3613 /* Check the template arguments. */
3627 /* Ignore the declaration of a capture proxy for a parameter pack. */
3635 /* Fall through. */
3680 {
3686 }
3689 {
3690 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3691 type_pack_expansion_p to false so that any placeholders
3692 within the expression don't get marked as parameter packs. */
3700 }
3704 }
3707 }
3709 /* Determines if the expression or type T uses any parameter packs. */
3710 bool
3712 {
3721 }
3723 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3724 representation a base-class initializer into a parameter pack
3725 expansion. If all goes well, the resulting node will be an
3726 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3727 respectively. */
3728 tree
3730 {
3731 tree result;
3740 {
3741 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3742 class initializer. In this case, the TREE_PURPOSE will be a
3743 _TYPE node (representing the base class expansion we're
3744 initializing) and the TREE_VALUE will be a TREE_LIST
3745 containing the initialization arguments.
3747 The resulting expansion looks somewhat different from most
3748 expansions. Rather than returning just one _EXPANSION, we
3749 return a TREE_LIST whose TREE_PURPOSE is a
3750 TYPE_PACK_EXPANSION containing the bases that will be
3751 initialized. The TREE_VALUE will be identical to the
3752 original TREE_VALUE, which is a list of arguments that will
3753 be passed to each base. We do not introduce any new pack
3754 expansion nodes into the TREE_VALUE (although it is possible
3755 that some already exist), because the TREE_PURPOSE and
3756 TREE_VALUE all need to be expanded together with the same
3757 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3758 resulting TREE_PURPOSE will mention the parameter packs in
3759 both the bases and the arguments to the bases. */
3760 tree purpose;
3761 tree value;
3764 /* Determine which parameter packs will be used by the base
3765 class expansion. */
3774 {
3777 arg);
3780 }
3783 {
3784 /* Collect the sets of parameter packs used in each of the
3785 initialization arguments. */
3787 {
3788 /* Determine which parameter packs will be expanded in this
3789 argument. */
3792 }
3793 }
3797 /* Create the pack expansion type for the base type. */
3803 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3804 they will rarely be compared to anything. */
3808 }
3813 /* Build the PACK_EXPANSION_* node. */
3814 result = for_types
3819 {
3820 /* Propagate type and const-expression information. */
3823 /* Mark this read now, since the expansion might be length 0. */
3825 }
3826 else
3827 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3828 they will rarely be compared to anything. */
3831 /* Determine which parameter packs will be expanded. */
3838 /* Make sure we found some parameter packs. */
3840 {
3842 {
3845 else
3847 }
3849 }
3855 }
3857 /* Checks T for any "bare" parameter packs, which have not yet been
3858 expanded, and issues an error if any are found. This operation can
3859 only be done on full expressions or types (e.g., an expression
3860 statement, "if" condition, etc.), because we could have expressions like:
3862 foo(f(g(h(args)))...)
3864 where "args" is a parameter pack. check_for_bare_parameter_packs
3865 should not be called for the subexpressions args, h(args),
3866 g(h(args)), or f(g(h(args))), because we would produce erroneous
3867 error messages.
3869 Returns TRUE and emits an error if there were bare parameter packs,
3870 returns FALSE otherwise. */
3871 bool
3873 {
3880 /* A lambda might use a parameter pack from the containing context. */
3894 {
3898 {
3909 else
3914 else
3918 }
3921 }
3924 }
3926 /* Expand any parameter packs that occur in the template arguments in
3927 ARGS. */
3928 tree
3930 {
3939 /* First, determine if we need to expand anything, and the number of
3940 slots we'll need. */
3942 {
3947 {
3951 else
3953 }
3954 else
3955 {
3957 num_result_args++;
3958 }
3959 }
3961 /* If no expansion is necessary, we're done. */
3965 /* Expand arguments. */
3968 non_default_args_count =
3971 {
3974 {
3981 }
3982 else
3983 {
3986 }
3987 }
3991 }
3993 /* Checks if DECL shadows a template parameter.
3995 [temp.local]: A template-parameter shall not be redeclared within its
3996 scope (including nested scopes).
3998 Emits an error and returns TRUE if the DECL shadows a parameter,
3999 returns FALSE otherwise. */
4001 bool
4003 {
4004 tree olddecl;
4006 /* If we're not in a template, we can't possibly shadow a template
4007 parameter. */
4011 /* Figure out what we're shadowing. */
4015 /* If there's no previous binding for this name, we're not shadowing
4016 anything, let alone a template parameter. */
4020 /* If we're not shadowing a template parameter, we're done. Note
4021 that OLDDECL might be an OVERLOAD (or perhaps even an
4022 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4023 node. */
4027 /* We check for decl != olddecl to avoid bogus errors for using a
4028 name inside a class. We check TPFI to avoid duplicate errors for
4029 inline member templates. */
4035 /* Don't complain about the injected class name, as we've already
4036 complained about the class itself. */
4043 else
4048 }
4050 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4051 ORIG_LEVEL, DECL, and TYPE. */
4053 static tree
4057 tree decl,
4058 tree type)
4059 {
4070 }
4072 /* Find the canonical type parameter for the given template type
4073 parameter. Returns the canonical type parameter, which may be TYPE
4074 if no such parameter existed. */
4076 static tree
4078 {
4079 tree list;
4093 else
4094 {
4098 }
4099 }
4101 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4102 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4103 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4104 new one is created. */
4106 static tree
4108 tsubst_flags_t complain)
4109 {
4114 {
4133 /* Template template parameters need this. */
4135 {
4142 }
4143 }
4146 }
4148 /* Process information from new template parameter PARM and append it
4149 to the LIST being built. This new parameter is a non-type
4150 parameter iff IS_NON_TYPE is true. This new parameter is a
4151 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4152 is in PARM_LOC. */
4154 tree
4157 {
4166 {
4170 {
4174 else
4176 }
4179 }
4182 {
4188 {
4189 /* [temp.param]
4191 The top-level cv-qualifiers on the template-parameter are
4192 ignored when determining its type. */
4197 && !is_parameter_pack
4198 /* If we're in a nested template parameter list, the template
4199 template parameter could be a parameter pack. */
4201 {
4202 /* This template parameter is not a parameter pack, but it
4203 should be. Complain about "bare" parameter packs. */
4206 /* Recover by calling this a parameter pack. */
4208 }
4209 }
4211 /* A template parameter is not modifiable. */
4220 processing_template_decl,
4225 }
4226 else
4227 {
4228 tree t;
4232 {
4234 /* This is for distinguishing between real templates and template
4235 template parameters */
4239 }
4240 else
4241 {
4243 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4246 }
4253 processing_template_decl,
4257 }
4261 /* Build requirements for the type/template parameter.
4262 This must be done after SET_DECL_TEMPLATE_PARM_P or
4263 process_template_parm could fail. */
4268 /* Build the parameter node linking the parameter declaration,
4269 its default argument (if any), and its constraints (if any). */
4274 }
4276 /* The end of a template parameter list has been reached. Process the
4277 tree list into a parameter vector, converting each parameter into a more
4278 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4279 as PARM_DECLs. */
4281 tree
4283 {
4288 /* Pop the dummy parameter level and add the real one. */
4291 current_template_parms
4296 {
4300 }
4305 }
4307 // Explicitly indicate the end of the template parameter list. We assume
4308 // that the current template parameters have been constructed and/or
4309 // managed explicitly, as when creating new template template parameters
4310 // from a shorthand constraint.
4311 void
4313 {
4315 }
4317 /* end_template_decl is called after a template declaration is seen. */
4319 void
4321 {
4327 /* This matches the pushlevel in begin_template_parm_list. */
4332 }
4334 /* Takes a TREE_LIST representing a template parameter and convert it
4335 into an argument suitable to be passed to the type substitution
4336 functions. Note that If the TREE_LIST contains an error_mark
4337 node, the returned argument is error_mark_node. */
4339 tree
4341 {
4354 {
4358 {
4359 /* Turn this argument into a TYPE_ARGUMENT_PACK
4360 with a single element, which expands T. */
4369 }
4370 }
4371 else
4372 {
4376 {
4377 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4378 with a single element, which expands T. */
4388 }
4389 else
4391 }
4393 }
4395 /* Given a single level of template parameters (a TREE_VEC), return it
4396 as a set of template arguments. */
4398 static tree
4400 {
4410 }
4412 /* Given a set of template parameters, return them as a set of template
4413 arguments. The template parameters are represented as a TREE_VEC, in
4414 the form documented in cp-tree.h for template arguments. */
4416 static tree
4418 {
4419 tree header;
4424 /* If there is only one level of template parameters, we do not
4425 create a TREE_VEC of TREE_VECs. Instead, we return a single
4426 TREE_VEC containing the arguments. */
4431 {
4436 else
4438 }
4441 }
4443 /* Within the declaration of a template, return the currently active
4444 template parameters as an argument TREE_VEC. */
4446 static tree
4448 {
4450 }
4452 /* Update the declared TYPE by doing any lookups which were thought to be
4453 dependent, but are not now that we know the SCOPE of the declarator. */
4455 tree
4457 {
4468 /* Don't bother building up the args in this case. */
4470 {
4471 /* tsubst in the args corresponding to the template parameters,
4472 including auto if present. Most things will be unchanged, but
4473 make_typename_type and tsubst_qualified_id will resolve
4474 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4477 tree pushed;
4479 {
4483 }
4488 }
4494 {
4497 else
4499 }
4501 }
4503 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4504 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4505 the new template is a member template. */
4507 tree
4509 {
4517 }
4519 struct template_parm_data
4520 {
4521 /* The level of the template parameters we are currently
4522 processing. */
4525 /* The index of the specialization argument we are currently
4526 processing. */
4529 /* An array whose size is the number of template parameters. The
4530 elements are nonzero if the parameter has been used in any one
4531 of the arguments processed so far. */
4534 /* An array whose size is the number of template arguments. The
4535 elements are nonzero if the argument makes use of template
4536 parameters of this level. */
4538 };
4540 /* Subroutine of push_template_decl used to see if each template
4541 parameter in a partial specialization is used in the explicit
4542 argument list. If T is of the LEVEL given in DATA (which is
4543 treated as a template_parm_data*), then DATA->PARMS is marked
4544 appropriately. */
4546 static int
4548 {
4556 {
4559 }
4561 /* In C++17 the type of a non-type argument is a deduced context. */
4566 data,
4567 NULL,
4570 /* Return zero so that for_each_template_parm will continue the
4571 traversal of the tree; we want to mark *every* template parm. */
4573 }
4575 /* Process the partial specialization DECL. */
4577 static tree
4579 {
4586 tree inner_parms;
4587 tree inst;
4597 /* A concept cannot be specialized. */
4599 {
4602 }
4607 /* We check that each of the template parameters given in the
4608 partial specialization is used in the argument list to the
4609 specialization. For example:
4611 template <class T> struct S;
4612 template <class T> struct S<T*>;
4614 The second declaration is OK because `T*' uses the template
4615 parameter T, whereas
4617 template <class T> struct S<int>;
4619 is no good. Even trickier is:
4621 template <class T>
4622 struct S1
4623 {
4624 template <class U>
4625 struct S2;
4626 template <class U>
4627 struct S2<T>;
4628 };
4630 The S2<T> declaration is actually invalid; it is a
4631 full-specialization. Of course,
4633 template <class U>
4634 struct S2<T (*)(U)>;
4636 or some such would have been OK. */
4644 {
4649 NULL,
4651 }
4654 {
4655 /* One of the template parms was not used in a deduced context in the
4656 specialization. */
4658 {
4662 }
4666 }
4671 /* [temp.class.spec]
4673 The argument list of the specialization shall not be identical to
4674 the implicit argument list of the primary template. */
4675 tree main_args
4678 && (!flag_concepts
4681 {
4685 else
4689 }
4691 /* A partial specialization that replaces multiple parameters of the
4692 primary template with a pack expansion is less specialized for those
4693 parameters. */
4695 {
4697 "primary template because it replaces multiple parameters "
4700 /* Avoid crash in process_partial_specialization. */
4702 }
4704 /* If we aren't in a dependent class, we can actually try deduction. */
4706 /* FIXME we should be able to handle a partial specialization of a
4707 partial instantiation, but currently we can't (c++/41727). */
4710 {
4714 maintmpl);
4715 }
4717 /* [temp.class.spec]
4719 A partially specialized non-type argument expression shall not
4720 involve template parameters of the partial specialization except
4721 when the argument expression is a simple identifier.
4723 The type of a template parameter corresponding to a specialized
4724 non-type argument shall not be dependent on a parameter of the
4725 specialization.
4727 Also, we verify that pack expansions only occur at the
4728 end of the argument list. */
4732 {
4739 {
4740 /* Extract the arguments from the argument pack. We'll be
4741 iterating over these in the following loop. */
4744 }
4747 {
4749 /* Get the Jth argument in the parameter pack. */
4753 {
4754 /* Pack expansions must come at the end of the
4755 argument list. */
4758 {
4762 else
4765 }
4766 }
4769 /* We only care about the pattern. */
4775 /* This next two lines are the `argument expression is not just a
4776 simple identifier' condition and also the `specialized
4777 non-type argument' bit. */
4781 {
4785 arg);
4786 else
4787 {
4788 /* Look at the corresponding template parameter,
4789 marking which template parameters its type depends
4790 upon. */
4794 {
4795 /* We haven't yet initialized TPD2. Do so now. */
4797 /* The number of parameters here is the number in the
4798 main template, which, as checked in the assertion
4799 above, is NARGS. */
4803 }
4805 /* Mark the template parameters. But this time, we're
4806 looking for the template parameters of the main
4807 template, not in the specialization. */
4814 NULL,
4818 {
4819 /* The type depended on some template parameters.
4820 If they are fully specialized in the
4821 specialization, that's OK. */
4830 "type %qT of template argument %qE depends "
4832 "type %qT of template argument %qE depends "
4834 type,
4835 arg);
4836 }
4837 }
4838 }
4839 }
4840 }
4842 /* We should only get here once. */
4846 // Build the template decl.
4855 /* Give template template parms a DECL_CONTEXT of the template
4856 for which they are a parameter. */
4858 {
4862 }
4865 /* We didn't register this in check_explicit_specialization so we could
4866 wait until the constraints were set. */
4868 else
4878 {
4884 {
4892 "declaration of %qD ambiguates earlier template "
4896 "partial specialization of %qD after instantiation "
4898 }
4899 }
4902 }
4904 /* PARM is a template parameter of some form; return the corresponding
4905 TEMPLATE_PARM_INDEX. */
4907 static tree
4909 {
4922 }
4924 /* Subroutine of fixed_parameter_pack_p below. Look for any template
4925 parameter packs used by the template parameter PARM. */
4927 static void
4929 {
4930 /* A type parm can't refer to another parm. */
4934 {
4938 }
4945 }
4947 /* PARM is a template parameter pack. Return any parameter packs used in
4948 its type or the type of any of its template parameters. If there are
4949 any such packs, it will be instantiated into a fixed template parameter
4950 list by partial instantiation rather than be fully deduced. */
4952 tree
4954 {
4955 /* This can only be true in a member template. */
4958 /* This can only be true for a parameter pack. */
4961 /* A type parm can't refer to another parm. */
4975 }
4977 /* Check that a template declaration's use of default arguments and
4978 parameter packs is not invalid. Here, PARMS are the template
4979 parameters. IS_PRIMARY is true if DECL is the thing declared by
4980 a primary template. IS_PARTIAL is true if DECL is a partial
4981 specialization.
4983 IS_FRIEND_DECL is nonzero if DECL is a friend function template
4984 declaration (but not a definition); 1 indicates a declaration, 2
4985 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4986 emitted for extraneous default arguments.
4988 Returns TRUE if there were no errors found, FALSE otherwise. */
4990 bool
4993 {
4996 tree parm_level;
4999 /* [temp.param]
5001 A default template-argument shall not be specified in a
5002 function template declaration or a function template definition, nor
5003 in the template-parameter-list of the definition of a member of a
5004 class template. */
5008 /* You can't have a function template declaration in a local
5009 scope, nor you can you define a member of a class template in a
5010 local scope. */
5018 /* A lambda doesn't have an explicit declaration; don't complain
5019 about the parms of the enclosing class. */
5026 /* If this is either a friend defined in the scope of the class
5027 or a member function. */
5033 /* And, if it was a member function, it really was defined in
5034 the scope of the class. */
5037 /* We already checked these parameters when the template was
5038 declared, so there's no need to do it again now. This function
5039 was defined in class scope, but we're processing its body now
5040 that the class is complete. */
5043 /* Core issue 226 (C++0x only): the following only applies to class
5044 templates. */
5047 {
5048 /* [temp.param]
5050 If a template-parameter has a default template-argument, all
5051 subsequent template-parameters shall have a default
5052 template-argument supplied. */
5054 {
5061 {
5071 {
5073 /* For better subsequent error-recovery, we indicate that
5074 there should have been a default argument. */
5077 }
5079 && !is_friend_decl
5080 /* Don't complain about an enclosing partial
5081 specialization. */
5086 /* A fixed parameter pack will be partially
5087 instantiated into a fixed length list. */
5089 {
5090 /* A primary class template can only have one
5091 parameter pack, at the end of the template
5092 parameter list. */
5100 }
5101 }
5102 }
5103 }
5106 || is_partial
5107 || !is_primary
5109 /* For an ordinary class template, default template arguments are
5110 allowed at the innermost level, e.g.:
5111 template <class T = int>
5112 struct S {};
5113 but, in a partial specialization, they're not allowed even
5114 there, as we have in [temp.class.spec]:
5116 The template parameter list of a specialization shall not
5117 contain default template argument values.
5119 So, for a partial specialization, or for a function template
5120 (in C++98/C++03), we look at all of them. */
5121 ;
5122 else
5123 /* But, for a primary class template that is not a partial
5124 specialization we look at all template parameters except the
5125 innermost ones. */
5128 /* Figure out what error message to issue. */
5143 else
5144 /* Per [temp.param]/9, "A default template-argument shall not be
5145 specified in the template-parameter-lists of the definition of
5146 a member of a class template that appears outside of the member's
5147 class.", thus if we aren't handling a member of a class template
5148 there is no need to examine the parameters. */
5152 /* If we're inside a class definition, there's no need to
5153 examine the parameters to the class itself. On the one
5154 hand, they will be checked when the class is defined, and,
5155 on the other, default arguments are valid in things like:
5156 template <class T = double>
5157 struct S { template <class U> void f(U); };
5158 Here the default argument for `S' has no bearing on the
5159 declaration of `f'. */
5161 else
5162 /* Check everything. */
5168 {
5175 {
5180 {
5182 {
5189 }
5191 /* Clear out the default argument so that we are not
5192 confused later. */
5194 }
5195 }
5197 /* At this point, if we're still interested in issuing messages,
5198 they must apply to classes surrounding the object declared. */
5202 }
5205 }
5207 /* Worker for push_template_decl_real, called via
5208 for_each_template_parm. DATA is really an int, indicating the
5209 level of the parameters we are interested in. If T is a template
5210 parameter of that level, return nonzero. */
5212 static int
5214 {
5220 else
5223 }
5225 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5226 DATA is really an int, indicating the innermost outer level of parameters.
5227 If T is a template parameter of that level or further out, return
5228 nonzero. */
5230 static int
5232 {
5238 else
5241 }
5243 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5244 parameters given by current_template_args, or reuses a
5245 previously existing one, if appropriate. Returns the DECL, or an
5246 equivalent one, if it is replaced via a call to duplicate_decls.
5248 If IS_FRIEND is true, DECL is a friend declaration. */
5250 tree
5252 {
5253 tree tmpl;
5254 tree args;
5255 tree info;
5256 tree ctx;
5260 /* True if the template is a member template, in the sense of
5261 [temp.mem]. */
5267 /* See if this is a partial specialization. */
5280 /* For a friend, we want the context of the friend function, not
5281 the type of which it is a friend. */
5285 /* In the case of a virtual function, we want the class in which
5286 it is defined. */
5288 else
5289 /* Otherwise, if we're currently defining some class, the DECL
5290 is assumed to be a member of the class. */
5299 /* See if this is a primary template. */
5302 /* A friend template that specifies a class context, i.e.
5303 template <typename T> friend void A<T>::f();
5304 is not primary. */
5309 else
5313 {
5320 {
5323 }
5325 {
5327 {
5330 }
5332 {
5333 /* [temp.mem]
5335 A destructor shall not be a member template. */
5338 }
5345 {
5346 /* [basic.stc.dynamic.allocation]
5348 An allocation function can be a function
5349 template. ... Template allocation functions shall
5350 have two or more parameters. */
5353 }
5354 }
5357 {
5358 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5361 {
5367 }
5368 }
5371 /* alias-declaration */
5375 else
5376 {
5379 }
5380 }
5382 /* Check to see that the rules regarding the use of default
5383 arguments are not being violated. */
5387 /* Ensure that there are no parameter packs in the type of this
5388 declaration that have not been expanded. */
5390 {
5391 /* Check each of the arguments individually to see if there are
5392 any bare parameter packs. */
5398 {
5401 {
5402 /* This is a PARM_DECL that contains unexpanded parameter
5403 packs. We have already complained about this in the
5404 check_for_bare_parameter_packs call, so just replace
5405 these types with ERROR_MARK_NODE. */
5408 }
5412 }
5414 /* Check for bare parameter packs in the return type and the
5415 exception specifiers. */
5417 /* Errors were already issued, set return type to int
5418 as the frontend doesn't expect error_mark_node as
5419 the return type. */
5423 }
5428 {
5431 }
5444 {
5449 /* If DECL is a TYPE_DECL for a class-template, then there won't
5450 be DECL_LANG_SPECIFIC. The information equivalent to
5451 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5455 {
5456 /* Since a template declaration already existed for this
5457 class-type, we must be redeclaring it here. Make sure
5458 that the redeclaration is valid. */
5460 current_template_parms,
5462 /* We don't need to create a new TEMPLATE_DECL; just use the
5463 one we already had. */
5465 }
5466 else
5467 {
5469 member_template_p);
5474 {
5475 /* A specialization of a member template of a template
5476 class. */
5480 }
5481 }
5482 }
5483 else
5484 {
5490 {
5493 }
5501 {
5502 tree new_tmpl;
5504 /* The declaration is a specialization of a member
5505 template, declared outside the class. Therefore, the
5506 innermost template arguments will be NULL, so we
5507 replace them with the arguments determined by the
5508 earlier call to check_explicit_specialization. */
5511 new_tmpl
5513 member_template_p);
5523 args,
5526 }
5528 /* Make sure the template headers we got make sense. */
5533 {
5538 }
5539 else
5541 {
5546 {
5550 else
5554 /* Avoid crash in import_export_decl. */
5557 }
5562 /* Can happen in erroneous input. */
5564 else
5566 }
5568 /* Check that the parms are used in the appropriate qualifying scopes
5569 in the declarator. */
5573 {
5579 /* Avoid crash in import_export_decl. */
5582 }
5583 }
5588 /* Push template declarations for global functions and types. Note
5589 that we do not try to push a global template friend declared in a
5590 template class; such a thing may well depend on the template
5591 parameters of the class. */
5594 {
5599 /* Hide template friend classes that haven't been declared yet. */
5601 {
5604 }
5605 }
5608 {
5613 /* Give template template parms a DECL_CONTEXT of the template
5614 for which they are a parameter. */
5617 {
5621 }
5627 }
5629 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5630 back to its most general template. If TMPL is a specialization,
5631 ARGS may only have the innermost set of arguments. Add the missing
5632 argument levels if necessary. */
5640 else
5641 {
5646 }
5649 && !is_friend
5652 /* Set DECL_COMDAT on template instantiations; if we force
5653 them to be emitted by explicit instantiation or -frepo,
5654 mark_needed will tell cgraph to do the right thing. */
5658 }
5660 tree
5662 {
5664 }
5666 /* FN is an inheriting constructor that inherits from the constructor
5667 template INHERITED; turn FN into a constructor template with a matching
5668 template header. */
5670 tree
5672 {
5673 tree inner_parms
5676 tree parms
5687 }
5689 /* Called when a class template TYPE is redeclared with the indicated
5690 template PARMS, e.g.:
5692 template <class T> struct S;
5693 template <class T> struct S {}; */
5695 bool
5697 {
5698 tree tmpl;
5699 tree tmpl_parms;
5703 {
5706 }
5710 /* The type is nested in some template class. Nothing to worry
5711 about here; there are no new template parameters for the nested
5712 type. */
5716 {
5718 tmpl);
5720 }
5726 {
5736 }
5739 {
5740 tree tmpl_parm;
5741 tree parm;
5742 tree tmpl_default;
5743 tree parm_default;
5757 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5758 TEMPLATE_DECL. */
5768 {
5772 }
5775 {
5776 /* We have in [temp.param]:
5778 A template-parameter may not be given default arguments
5779 by two different declarations in the same scope. */
5784 }
5787 /* Update the previous template parameters (which are the ones
5788 that will really count) with the new default value. */
5791 /* Update the new parameters, too; they'll be used as the
5792 parameters for any members. */
5795 /* Give each template template parm in this redeclaration a
5796 DECL_CONTEXT of the template for which they are a parameter. */
5798 {
5801 }
5805 }
5807 // Cannot redeclare a class template with a different set of constraints.
5809 {
5814 }
5817 }
5819 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5820 to be used when the caller has already checked
5821 (processing_template_decl
5822 && !instantiation_dependent_expression_p (expr)
5823 && potential_constant_expression (expr))
5824 and cleared processing_template_decl. */
5826 tree
5828 {
5831 complain,
5835 }
5837 /* Simplify EXPR if it is a non-dependent expression. Returns the
5838 (possibly simplified) expression. */
5840 tree
5842 {
5846 /* If we're in a template, but EXPR isn't value dependent, simplify
5847 it. We're supposed to treat:
5849 template <typename T> void f(T[1 + 1]);
5850 template <typename T> void f(T[2]);
5852 as two declarations of the same function, for example. */
5855 {
5856 processing_template_decl_sentinel s;
5858 }
5860 }
5862 tree
5864 {
5866 }
5868 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
5869 an uninstantiated expression. */
5871 tree
5873 {
5877 {
5880 else
5881 {
5882 processing_template_decl_sentinel s;
5884 }
5885 }
5887 }
5889 /* True iff T is a specialization of a variable template. */
5891 bool
5893 {
5898 }
5900 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5901 template declaration, or a TYPE_DECL for an alias declaration. */
5903 bool
5905 {
5913 }
5915 /* Return TRUE iff T is a specialization of an alias template. */
5917 bool
5919 {
5920 /* It's an alias template specialization if it's an alias and its
5921 TYPE_NAME is a specialization of a primary template. */
5927 }
5929 /* An alias template is complex from a SFINAE perspective if a template-id
5930 using that alias can be ill-formed when the expansion is not, as with
5931 the void_t template. We determine this by checking whether the
5932 expansion for the alias template uses all its template parameters. */
5934 struct uses_all_template_parms_data
5935 {
5938 };
5940 static int
5942 {
5950 }
5952 static bool
5954 {
5969 }
5971 /* Return TRUE iff T is a specialization of a complex alias template with
5972 dependent template-arguments. */
5974 bool
5976 {
5989 }
5991 /* Return the number of innermost template parameters in TMPL. */
5993 static int
5995 {
5998 }
6000 /* Return either TMPL or another template that it is equivalent to under DR
6001 1286: An alias that just changes the name of a template is equivalent to
6002 the other template. */
6004 static tree
6006 {
6009 {
6010 /* Determine if the alias is equivalent to an underlying template. */
6022 tree alias_args = INNERMOST_TEMPLATE_ARGS
6027 /* Alias is equivalent. Strip it and repeat. */
6029 }
6032 }
6034 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6035 must be a reference-to-function or a pointer-to-function type, as specified
6036 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6037 and check that the resulting function has external linkage. */
6039 static tree
6041 tsubst_flags_t complain)
6042 {
6045 linkage_kind linkage;
6060 /* [temp.arg.nontype]/1
6062 A template-argument for a non-type, non-template template-parameter
6063 shall be one of:
6064 [...]
6065 -- the address of an object or function with external [C++11: or
6066 internal] linkage. */
6069 {
6071 {
6077 else
6080 }
6082 }
6086 {
6088 {
6093 else
6097 }
6099 }
6101 accept:
6108 }
6110 /* Subroutine of convert_nontype_argument.
6111 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6112 Emit an error otherwise. */
6114 static bool
6116 tsubst_flags_t complain)
6117 {
6134 {
6139 else
6141 }
6143 }
6145 /* Returns TRUE iff the address of OP is value-dependent.
6147 14.6.2.4 [temp.dep.temp]:
6148 A non-integral non-type template-argument is dependent if its type is
6149 dependent or it has either of the following forms
6150 qualified-id
6151 & qualified-id
6152 and contains a nested-name-specifier which specifies a class-name that
6153 names a dependent type.
6155 We generalize this to just say that the address of a member of a
6156 dependent class is value-dependent; the above doesn't cover the
6157 address of a static data member named with an unqualified-id. */
6159 static bool
6161 {
6162 /* We could use get_inner_reference here, but there's no need;
6163 this is only relevant for template non-type arguments, which
6164 can only be expressed as &id-expression. */
6166 {
6170 }
6173 }
6175 /* The next set of functions are used for providing helpful explanatory
6176 diagnostics for failed overload resolution. Their messages should be
6177 indented by two spaces for consistency with the messages in
6178 call.c */
6180 static int
6182 {
6184 }
6186 /* Other failure functions should call this one, to provide a single function
6187 for setting a breakpoint on. */
6189 static int
6191 {
6193 }
6195 static int
6197 {
6202 }
6204 static int
6206 {
6212 }
6214 static int
6216 {
6220 }
6222 static int
6224 {
6227 " template parameter %qD is not a parameter pack, but "
6231 }
6233 static int
6235 {
6238 " template argument %qE does not match "
6242 }
6244 static int
6246 {
6250 }
6252 static int
6254 {
6260 }
6262 static int
6264 {
6266 {
6271 else
6273 " deduced conflicting values for non-type parameter "
6275 }
6277 }
6279 static int
6281 {
6284 " variable-sized array type %qT is not "
6286 arg);
6288 }
6290 static int
6292 {
6296 arg);
6298 }
6300 static int
6302 {
6304 {
6310 else
6315 }
6317 }
6319 static int
6321 {
6323 }
6325 static int
6328 {
6330 }
6332 static int
6335 {
6341 }
6343 static int
6346 {
6349 {
6357 }
6359 }
6361 static int
6363 {
6366 " template parameters of a template template argument are "
6369 }
6371 static int
6373 {
6379 }
6381 static int
6383 {
6388 }
6390 /* Attempt to convert the non-type template parameter EXPR to the
6391 indicated TYPE. If the conversion is successful, return the
6392 converted value. If the conversion is unsuccessful, return
6393 NULL_TREE if we issued an error message, or error_mark_node if we
6394 did not. We issue error messages for out-and-out bad template
6395 parameters, but not simply because the conversion failed, since we
6396 might be just trying to do argument deduction. Both TYPE and EXPR
6397 must be non-dependent.
6399 The conversion follows the special rules described in
6400 [temp.arg.nontype], and it is much more strict than an implicit
6401 conversion.
6403 This function is called twice for each template argument (see
6404 lookup_template_class for a more accurate description of this
6405 problem). This means that we need to handle expressions which
6406 are not valid in a C++ source, but can be created from the
6407 first call (for instance, casts to perform conversions). These
6408 hacks can go away after we fix the double coercion problem. */
6410 static tree
6412 {
6413 tree expr_type;
6417 /* Detect immediately string literals as invalid non-type argument.
6418 This special-case is not needed for correctness (we would easily
6419 catch this later), but only to provide better diagnostic for this
6420 common user mistake. As suggested by DR 100, we do not mention
6421 linkage issues in the diagnostic as this is not the point. */
6422 /* FIXME we're making this OK. */
6424 {
6430 }
6432 /* Add the ADDR_EXPR now for the benefit of
6433 value_dependent_expression_p. */
6436 {
6440 }
6442 /* If we are in a template, EXPR may be non-dependent, but still
6443 have a syntactic, rather than semantic, form. For example, EXPR
6444 might be a SCOPE_REF, rather than the VAR_DECL to which the
6445 SCOPE_REF refers. Preserving the qualifying scope is necessary
6446 so that access checking can be performed when the template is
6447 instantiated -- but here we need the resolved form so that we can
6448 convert the argument. */
6460 /* If the argument is non-dependent, perform any conversions in
6461 non-dependent context as well. */
6469 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6470 to a non-type argument of "nullptr". */
6474 /* In C++11, integral or enumeration non-type template arguments can be
6475 arbitrary constant expressions. Pointer and pointer to
6476 member arguments can be general constant expressions that evaluate
6477 to a null value, but otherwise still need to be of a specific form. */
6479 {
6481 /* A PTRMEM_CST is already constant, and a valid template
6482 argument for a parameter of pointer to member type, we just want
6483 to leave it in that form rather than lower it to a
6487 {
6488 /* C++17: A template-argument for a non-type template-parameter shall
6489 be a converted constant expression (8.20) of the type of the
6490 template-parameter. */
6496 }
6498 {
6503 }
6504 }
6508 else
6511 /* HACK: Due to double coercion, we can get a
6512 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6513 which is the tree that we built on the first call (see
6514 below when coercing to reference to object or to reference to
6515 function). We just strip everything and get to the arg.
6516 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6517 for examples. */
6519 {
6525 {
6526 /* ??? Maybe we could use convert_from_reference here, but we
6527 would need to relax its constraints because the NOP_EXPR
6528 could actually change the type to something more cv-qualified,
6529 and this is not folded by convert_from_reference. */
6534 && (same_type_ignoring_top_level_qualifiers_p
6537 {
6540 }
6541 }
6542 }
6544 /* [temp.arg.nontype]/5, bullet 1
6546 For a non-type template-parameter of integral or enumeration type,
6547 integral promotions (_conv.prom_) and integral conversions
6548 (_conv.integral_) are applied. */
6550 {
6552 {
6557 }
6562 /* Notice that there are constant expressions like '4 % 0' which
6563 do not fold into integer constants. */
6566 {
6568 {
6572 else
6578 /* else cxx_constant_value complained but gave us
6579 a real constant, so go ahead. */
6581 }
6582 else
6584 }
6586 /* Avoid typedef problems. */
6589 }
6590 /* [temp.arg.nontype]/5, bullet 2
6592 For a non-type template-parameter of type pointer to object,
6593 qualification conversions (_conv.qual_) and the array-to-pointer
6594 conversion (_conv.array_) are applied. */
6596 {
6599 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
6600 decay_conversion or an explicit cast. If it's a problematic cast,
6601 we'll complain about it below. */
6603 {
6608 {
6611 }
6612 }
6614 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6616 A template-argument for a non-type, non-template template-parameter
6617 shall be one of: [...]
6619 -- the name of a non-type template-parameter;
6620 -- the address of an object or function with external linkage, [...]
6621 expressed as "& id-expression" where the & is optional if the name
6622 refers to a function or array, or if the corresponding
6623 template-parameter is a reference.
6625 Here, we do not care about functions, as they are invalid anyway
6626 for a parameter of type pointer-to-object. */
6629 /* Non-type template parameters are OK. */
6630 ;
6634 {
6636 {
6639 "because %qD is a variable, not the address of "
6642 }
6644 {
6650 }
6651 /* Other values, like integer constants, might be valid
6652 non-type arguments of some other type. */
6654 }
6655 else
6656 {
6660 {
6665 }
6667 {
6673 }
6676 {
6681 }
6682 /* C++17: For a non-type template-parameter of reference or pointer
6683 type, the value of the constant expression shall not refer to (or
6684 for a pointer type, shall not be the address of):
6685 * a subobject (4.5),
6686 * a temporary object (15.2),
6687 * a string literal (5.13.5),
6688 * the result of a typeid expression (8.2.8), or
6689 * a predefined __func__ variable (11.4.1). */
6691 {
6694 decl);
6696 }
6700 {
6705 }
6707 {
6711 decl);
6713 }
6714 }
6721 }
6722 /* [temp.arg.nontype]/5, bullet 3
6724 For a non-type template-parameter of type reference to object, no
6725 conversions apply. The type referred to by the reference may be more
6726 cv-qualified than the (otherwise identical) type of the
6727 template-argument. The template-parameter is bound directly to the
6728 template-argument, which must be an lvalue. */
6730 {
6732 expr_type))
6736 {
6741 }
6744 {
6749 }
6751 /* [temp.arg.nontype]/1
6753 A template-argument for a non-type, non-template template-parameter
6754 shall be one of: [...]
6756 -- the address of an object or function with external linkage. */
6759 {
6762 {
6765 "because a reference variable does not have a constant "
6768 }
6769 }
6773 /* OK, dependent reference. We don't want to ask whether a DECL is
6775 else
6776 {
6778 {
6784 }
6786 /* DR 1155 allows internal linkage in C++11 and up. */
6789 {
6795 }
6798 }
6802 }
6803 /* [temp.arg.nontype]/5, bullet 4
6805 For a non-type template-parameter of type pointer to function, only
6806 the function-to-pointer conversion (_conv.func_) is applied. If the
6807 template-argument represents a set of overloaded functions (or a
6808 pointer to such), the matching function is selected from the set
6809 (_over.over_). */
6811 {
6812 /* If the argument is a template-id, we might not have enough
6813 context information to decay the pointer. */
6815 {
6819 }
6822 /* Null pointer values are OK in C++11. */
6828 }
6829 /* [temp.arg.nontype]/5, bullet 5
6831 For a non-type template-parameter of type reference to function, no
6832 conversions apply. If the template-argument represents a set of
6833 overloaded functions, the matching function is selected from the set
6834 (_over.over_). */
6836 {
6838 {
6840 {
6845 }
6847 }
6852 }
6853 /* [temp.arg.nontype]/5, bullet 6
6855 For a non-type template-parameter of type pointer to member function,
6856 no conversions apply. If the template-argument represents a set of
6857 overloaded member functions, the matching member function is selected
6858 from the set (_over.over_). */
6860 {
6865 /* [temp.arg.nontype] bullet 1 says the pointer to member
6866 expression must be a pointer-to-member constant. */
6871 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
6872 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
6875 }
6876 /* [temp.arg.nontype]/5, bullet 7
6878 For a non-type template-parameter of type pointer to data member,
6879 qualification conversions (_conv.qual_) are applied. */
6881 {
6882 /* [temp.arg.nontype] bullet 1 says the pointer to member
6883 expression must be a pointer-to-member constant. */
6891 }
6893 {
6895 {
6900 }
6902 }
6903 /* A template non-type parameter must be one of the above. */
6904 else
6907 /* Sanity check: did we actually convert the argument to the
6908 right type? */
6912 }
6914 /* Subroutine of coerce_template_template_parms, which returns 1 if
6915 PARM_PARM and ARG_PARM match using the rule for the template
6916 parameters of template template parameters. Both PARM and ARG are
6917 template parameters; the rest of the arguments are the same as for
6918 coerce_template_template_parms.
6919 */
6920 static int
6922 tree arg,
6923 tsubst_flags_t complain,
6924 tree in_decl,
6925 tree outer_args)
6926 {
6935 {
6937 /* We encounter instantiations of templates like
6938 template <template <template <class> class> class TT>
6939 class C; */
6940 {
6947 }
6948 /* Fall through. */
6953 /* Argument is a parameter pack but parameter is not. */
6958 /* The tsubst call is used to handle cases such as
6960 template <int> class C {};
6961 template <class T, template <T> class TT> class D {};
6962 D<int, C> d;
6964 i.e. the parameter list of TT depends on earlier parameters. */
6966 {
6971 }
6975 /* Argument is a parameter pack but parameter is not. */
6982 }
6985 }
6987 /* Coerce template argument list ARGLIST for use with template
6988 template-parameter TEMPL. */
6990 static tree
6992 tsubst_flags_t complain)
6993 {
6994 /* Consider an example where a template template parameter declared as
6996 template <class T, class U = std::allocator<T> > class TT
6998 The template parameter level of T and U are one level larger than
6999 of TT. To proper process the default argument of U, say when an
7000 instantiation `TT<int>' is seen, we need to build the full
7001 arguments containing {int} as the innermost level. Outer levels,
7002 available when not appearing as default template argument, can be
7003 obtained from the arguments of the enclosing template.
7005 Suppose that TT is later substituted with std::vector. The above
7006 instantiation is `TT<int, std::allocator<T> >' with TT at
7007 level 1, and T at level 2, while the template arguments at level 1
7008 becomes {std::vector} and the inner level 2 is {int}. */
7012 {
7014 /* We want arguments for the partial specialization, not arguments for
7015 the primary template. */
7017 else
7019 }
7021 {
7022 /* This is an argument of the current template, so we haven't set
7023 DECL_CONTEXT yet. */
7024 tree relevant_template_parms;
7026 /* Parameter levels that are greater than the level of the given
7027 template template parm are irrelevant. */
7034 }
7041 complain,
7044 }
7046 /* A cache of template template parameters with match-all default
7047 arguments. */
7049 static void
7051 {
7055 }
7056 static tree
7058 {
7063 }
7065 /* T is a bound template template-parameter. Copy its arguments into default
7066 arguments of the template template-parameter's template parameters. */
7068 static tree
7070 {
7093 {
7096 {
7099 }
7100 }
7104 }
7106 /* ARG is a bound potential template template-argument, and PARGS is a list
7107 of arguments for the corresponding template template-parameter. Adjust
7108 PARGS as appropriate for application to ARG's template, and if ARG is a
7109 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7110 arguments to the template template parameter. */
7112 static tree
7114 {
7118 {
7119 /* When comparing two template template-parameters in partial ordering,
7120 rewrite the one currently being used as an argument to have default
7121 arguments for all parameters. */
7127 }
7128 else
7129 {
7130 tree aparms
7135 }
7138 }
7140 /* Subroutine of unify for the case when PARM is a
7141 BOUND_TEMPLATE_TEMPLATE_PARM. */
7143 static int
7146 {
7150 /* The template template parm might be variadic and the argument
7151 not, so flatten both argument lists. */
7156 {
7157 /* In keeping with P0522R0, adjust P's template arguments
7158 to apply to A's template; then flatten it again. */
7167 /* If the P0522 adjustment eliminated a pack expansion, deduce
7168 empty packs. */
7174 }
7175 else
7176 {
7177 /* Deduce arguments T, i from TT<T> or TT<i>.
7178 We check each element of PARMVEC and ARGVEC individually
7179 rather than the whole TREE_VEC since they can have
7180 different number of elements, which is allowed under N2555. */
7184 /* Check if the parameters end in a pack, making them
7185 variadic. */
7192 /* If the template argument list of P contains a pack
7193 expansion that is not the last template argument, the
7194 entire template argument list is a non-deduced
7195 context. */
7213 DEDUCE_EXACT,
7216 }
7219 }
7221 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7222 template template parameters. Both PARM_PARMS and ARG_PARMS are
7223 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7224 or PARM_DECL.
7226 Consider the example:
7227 template <class T> class A;
7228 template<template <class U> class TT> class B;
7230 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7231 the parameters to A, and OUTER_ARGS contains A. */
7233 static int
7235 tree arg_parms,
7236 tsubst_flags_t complain,
7237 tree in_decl,
7238 tree outer_args)
7239 {
7251 {
7252 /* P0522R0: A template template-parameter P is at least as specialized as
7253 a template template-argument A if, given the following rewrite to two
7254 function templates, the function template corresponding to P is at
7255 least as specialized as the function template corresponding to A
7256 according to the partial ordering rules for function templates
7257 ([temp.func.order]). Given an invented class template X with the
7258 template parameter list of A (including default arguments):
7260 * Each of the two function templates has the same template parameters,
7261 respectively, as P or A.
7263 * Each function template has a single function parameter whose type is
7264 a specialization of X with template arguments corresponding to the
7265 template parameters from the respective function template where, for
7266 each template parameter PP in the template parameter list of the
7267 function template, a corresponding template argument AA is formed. If
7268 PP declares a parameter pack, then AA is the pack expansion
7269 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7271 If the rewrite produces an invalid type, then P is not at least as
7272 specialized as A. */
7274 /* So coerce P's args to apply to A's parms, and then deduce between A's
7275 args and the converted args. If that succeeds, A is at least as
7276 specialized as P, so they match.*/
7283 {
7289 }
7290 }
7292 /* Determine whether we have a parameter pack at the end of the
7293 template template parameter's template parameter list. */
7295 {
7302 {
7316 }
7317 }
7323 /* Check all of the template parameters except the parameter pack at
7324 the end (if any). */
7326 {
7335 outer_args))
7338 }
7341 {
7342 /* Check each of the template parameters in the template
7343 argument against the template parameter pack at the end of
7344 the template template parameter. */
7351 {
7358 outer_args))
7360 }
7361 }
7364 }
7366 /* Verifies that the deduced template arguments (in TARGS) for the
7367 template template parameters (in TPARMS) represent valid bindings,
7368 by comparing the template parameter list of each template argument
7369 to the template parameter list of its corresponding template
7370 template parameter, in accordance with DR150. This
7371 routine can only be called after all template arguments have been
7372 deduced. It will return TRUE if all of the template template
7373 parameter bindings are okay, FALSE otherwise. */
7374 bool
7376 {
7380 /* We're dealing with template parms in this process. */
7386 {
7391 {
7396 {
7397 /* Look inside the argument pack. */
7400 }
7403 {
7407 /* Extract the next argument from the argument
7408 pack. */
7412 /* Look at the pattern of the pack expansion. */
7415 /* Extract the template parameters from the template
7416 argument. */
7422 /* Verify that we can coerce the template template
7423 parameters from the template argument to the template
7424 parameter. This requires an exact match. */
7426 && !coerce_template_template_parms
7428 targ_parms,
7429 tf_none,
7430 tparm,
7431 targs))
7432 {
7435 }
7436 }
7437 }
7438 }
7440 out:
7444 }
7446 /* Since type attributes aren't mangled, we need to strip them from
7447 template type arguments. */
7449 static tree
7451 {
7461 }
7463 /* And from inside dependent non-type arguments like sizeof(Type). */
7465 static tree
7467 {
7477 }
7479 // A template declaration can be substituted for a constrained
7480 // template template parameter only when the argument is more
7481 // constrained than the parameter.
7482 static bool
7484 {
7487 /* For now, allow constrained template template arguments
7488 and unconstrained template template parameters. */
7494 // If the template parameter is constrained, we need to rewrite its
7495 // constraints in terms of the ARG's template parameters. This ensures
7496 // that all of the template parameter types will have the same depth.
7497 //
7498 // Note that this is only valid when coerce_template_template_parm is
7499 // true for the innermost template parameters of PARM and ARG. In other
7500 // words, because coercion is successful, this conversion will be valid.
7502 {
7509 }
7512 }
7514 // Convert a placeholder argument into a binding to the original
7515 // parameter. The original parameter is saved as the TREE_TYPE of
7516 // ARG.
7519 {
7522 }
7524 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
7525 because one of them is dependent. But we need to represent the
7526 conversion for the benefit of cp_tree_equal. */
7528 static tree
7530 {
7531 /* Auto parms get no conversion. */
7534 /* We don't need or want to add this conversion now if we're going to use the
7535 argument for deduction. */
7547 }
7549 /* Convert the indicated template ARG as necessary to match the
7550 indicated template PARM. Returns the converted ARG, or
7551 error_mark_node if the conversion was unsuccessful. Error and
7552 warning messages are issued under control of COMPLAIN. This
7553 conversion is for the Ith parameter in the parameter list. ARGS is
7554 the full set of template arguments deduced so far. */
7556 static tree
7558 tree arg,
7559 tree args,
7560 tsubst_flags_t complain,
7562 tree in_decl)
7563 {
7564 tree orig_arg;
7565 tree val;
7571 /* Trivially convert placeholders. */
7580 {
7581 /* The template argument was the name of some
7582 member function. That's usually
7583 invalid, but static members are OK. In any
7584 case, grab the underlying fields/functions
7585 and issue an error later if required. */
7588 }
7596 /* When determining whether an argument pack expansion is a template,
7597 look at the pattern. */
7601 /* Deal with an injected-class-name used as a template template arg. */
7603 {
7606 {
7616 }
7617 }
7619 is_tmpl_type =
7635 {
7637 {
7641 }
7644 "to refer to a type member of a template parameter, "
7649 typename_type,
7650 complain);
7653 }
7655 {
7657 {
7659 {
7671 else
7674 }
7675 }
7677 }
7679 {
7681 {
7688 else
7691 }
7693 }
7696 /* We already did the appropriate conversion when packing args. */
7699 {
7701 {
7703 /* The number of argument required is not known yet.
7704 Just accept it for now. */
7706 else
7707 {
7709 tree argparm;
7711 /* Strip alias templates that are equivalent to another
7712 template. */
7718 args))
7719 {
7722 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7723 TEMPLATE_DECL. */
7725 {
7730 }
7731 }
7732 else
7733 {
7735 {
7742 }
7745 }
7747 // Check that the constraints are compatible before allowing the
7748 // substitution.
7751 {
7753 {
7759 }
7761 }
7762 }
7763 }
7764 else
7766 /* We only form one instance of each template specialization.
7767 Therefore, if we use a non-canonical variant (i.e., a
7768 typedef), any future messages referring to the type will use
7769 the typedef, which is confusing if those future uses do not
7770 themselves also use the typedef. */
7773 }
7774 else
7775 {
7779 {
7783 }
7784 else
7792 /* We used to call digest_init here. However, digest_init
7793 will report errors, which we don't want when complain
7794 is zero. More importantly, digest_init will try too
7795 hard to convert things: for example, `0' should not be
7796 converted to pointer type at this point according to
7797 the standard. Accepting this is not merely an
7798 extension, since deciding whether or not these
7799 conversions can occur is part of determining which
7800 function template to call, or whether a given explicit
7801 argument specification is valid. */
7803 else
7804 {
7807 }
7817 {
7818 /* Reject template arguments that are references to built-in
7819 functions with no library fallbacks. */
7828 }
7831 {
7832 /* Strip typedefs from the SCOPE_REF. */
7835 complain);
7838 }
7839 }
7842 }
7844 /* Coerces the remaining template arguments in INNER_ARGS (from
7845 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
7846 Returns the coerced argument pack. PARM_IDX is the position of this
7847 parameter in the template parameter list. ARGS is the original
7848 template argument list. */
7849 static tree
7852 tree args,
7853 tree inner_args,
7855 tree new_args,
7857 tree in_decl,
7858 tsubst_flags_t complain)
7859 {
7862 tree packed_args;
7863 tree argument_pack;
7870 {
7871 /* When the template parameter is a non-type template parameter pack
7872 or template template parameter pack whose type or template
7873 parameters use parameter packs, we know exactly how many arguments
7874 we are looking for. Build a vector of the instantiated decls for
7875 these template parameters in PACKED_PARMS. */
7876 /* We can't use make_pack_expansion here because it would interpret a
7877 _DECL as a use rather than a declaration. */
7891 /* If we're doing a partial instantiation of a member template,
7892 verify that all of the types used for the non-type
7893 template parameter pack are, in fact, valid for non-type
7894 template parameters. */
7897 {
7900 {
7904 }
7905 /* We don't know how many args we have yet, just
7906 use the unconverted ones for now. */
7908 }
7911 }
7912 /* Check if we have a placeholder pack, which indicates we're
7913 in the context of a introduction list. In that case we want
7914 to match this pack to the single placeholder. */
7918 {
7921 }
7922 else
7925 /* Convert the remaining arguments, which will be a part of the
7926 parameter pack "parm". */
7929 {
7935 {
7936 /* Once we've packed as many args as we have types, stop. */
7940 /* We don't know how many args we have yet, just
7941 use the unconverted ones for now. */
7943 else
7945 }
7948 {
7951 }
7952 else
7955 in_decl);
7959 }
7963 {
7968 }
7973 else
7974 {
7977 }
7984 }
7986 /* Returns the number of pack expansions in the template argument vector
7987 ARGS. */
7989 static int
7991 {
7996 {
8000 }
8002 }
8004 /* Convert all template arguments to their appropriate types, and
8005 return a vector containing the innermost resulting template
8006 arguments. If any error occurs, return error_mark_node. Error and
8007 warning messages are issued under control of COMPLAIN.
8009 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8010 for arguments not specified in ARGS. Otherwise, if
8011 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
8012 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
8013 USE_DEFAULT_ARGS is false, then all arguments must be specified in
8014 ARGS. */
8016 static tree
8018 tree args,
8019 tree in_decl,
8020 tsubst_flags_t complain,
8023 {
8025 tree orig_inner_args;
8026 tree inner_args;
8027 tree new_args;
8028 tree new_inner_args;
8032 /* When used as a boolean value, indicates whether this is a
8033 variadic template parameter list. Since it's an int, we can also
8034 subtract it from nparms to get the number of non-variadic
8035 parameters. */
8040 /* Likewise for parameters with default arguments. */
8048 /* Determine if there are any parameter packs or default arguments. */
8050 {
8058 }
8061 /* If there are no parameters that follow a parameter pack, we need to
8062 expand any argument packs so that we can deduce a parameter pack from
8063 some non-packed args followed by an argument pack, as in variadic85.C.
8064 If there are such parameters, we need to leave argument packs intact
8065 so the arguments are assigned properly. This can happen when dealing
8066 with a nested class inside a partial specialization of a class
8067 template, as in variadic92.C, or when deducing a template parameter pack
8068 from a sub-declarator, as in variadic114.C. */
8072 /* Count any pack expansion args. */
8078 && require_all_args
8079 && !variadic_args_p
8080 && (!use_default_args
8083 {
8085 {
8087 {
8091 }
8092 else
8099 }
8102 }
8103 /* We can't pass a pack expansion to a non-pack parameter of an alias
8104 template (DR 1430). */
8108 && variadic_args_p
8110 {
8112 {
8114 {
8120 {
8123 "pack expansion argument for non-pack parameter "
8125 else
8127 "pack expansion argument for non-pack parameter "
8131 }
8132 }
8134 found:;
8135 }
8137 }
8139 /* We need to evaluate the template arguments, even though this
8140 template-id may be nested within a "sizeof". */
8149 {
8150 tree arg;
8151 tree parm;
8153 /* Get the Ith template parameter. */
8157 {
8160 }
8162 /* Calculate the next argument. */
8165 else
8170 {
8171 /* Some arguments will be placed in the
8172 template parameter pack PARM. */
8179 {
8180 /* We don't know how many args we have yet, just use the
8181 unconverted (and still packed) ones for now. */
8185 }
8189 /* Store this argument. */
8191 {
8192 lost++;
8193 /* We are done with all of the arguments. */
8195 }
8196 else
8197 {
8200 }
8203 }
8205 {
8207 {
8208 /* "If every valid specialization of a variadic template
8209 requires an empty template parameter pack, the template is
8210 ill-formed, no diagnostic required." So check that the
8211 pattern works with this parameter. */
8216 in_decl);
8218 {
8223 }
8225 /* Recover from missing typename. */
8229 /* We don't know how many args we have yet, just
8230 use the unconverted ones for now. */
8234 }
8235 }
8237 {
8238 /* There must be a default arg in this case. */
8241 /* The position of the first default template argument,
8242 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8243 Record that. */
8247 }
8248 else
8252 {
8255 }
8257 /* This only occurs if there was an error in the template
8258 parameter list itself (which we would already have
8259 reported) that we are trying to recover from, e.g., a class
8260 template with a parameter list such as
8261 template<typename..., typename>. */
8263 else
8269 lost++;
8271 }
8276 {
8278 {
8283 }
8285 }
8295 }
8297 /* Convert all template arguments to their appropriate types, and
8298 return a vector containing the innermost resulting template
8299 arguments. If any error occurs, return error_mark_node. Error and
8300 warning messages are not issued.
8302 Note that no function argument deduction is performed, and default
8303 arguments are used to fill in unspecified arguments. */
8304 tree
8306 {
8308 }
8310 /* Convert all template arguments to their appropriate type, and
8311 instantiate default arguments as needed. This returns a vector
8312 containing the innermost resulting template arguments, or
8313 error_mark_node if unsuccessful. */
8314 tree
8316 tsubst_flags_t complain)
8317 {
8319 }
8321 /* Like coerce_template_parms. If PARMS represents all template
8322 parameters levels, this function returns a vector of vectors
8323 representing all the resulting argument levels. Note that in this
8324 case, only the innermost arguments are coerced because the
8325 outermost ones are supposed to have been coerced already.
8327 Otherwise, if PARMS represents only (the innermost) vector of
8328 parameters, this function returns a vector containing just the
8329 innermost resulting arguments. */
8331 static tree
8333 tree args,
8334 tree in_decl,
8335 tsubst_flags_t complain,
8338 {
8341 tree coerced_args;
8344 {
8346 tree level;
8352 {
8353 tree l;
8357 require_all_args,
8358 use_default_args);
8359 else
8366 }
8367 }
8368 else
8371 require_all_args,
8372 use_default_args);
8374 }
8376 /* Returns 1 if template args OT and NT are equivalent. */
8378 int
8380 {
8389 /* For member templates */
8398 {
8415 }
8419 {
8422 /* Don't treat an alias template specialization with dependent
8423 arguments as equivalent to its underlying type when used as a
8424 template argument; we need them to be distinct so that we
8425 substitute into the specialization arguments at instantiation
8426 time. And aliases can't be equivalent without being ==, so
8427 we don't need to look any deeper.
8429 During partial ordering, however, we need to treat them normally so
8430 that we can order uses of the same alias with different
8431 cv-qualification (79960). */
8435 else
8437 }
8440 else
8441 {
8442 /* Try to treat a template non-type argument that has been converted
8443 to the parameter type as equivalent to one that hasn't yet. */
8456 }
8457 }
8459 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8460 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8461 NEWARG_PTR with the offending arguments if they are non-NULL. */
8463 int
8467 {
8480 {
8485 {
8491 }
8492 }
8494 }
8498 {
8500 }
8502 static void
8504 {
8514 /* We are called both from instantiate_decl, where we've already had a
8515 tinst_level pushed, and instantiate_template, where we haven't.
8516 Compensate. */
8527 else
8536 }
8539 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
8540 ARGLIST. Valid choices for FNS are given in the cp-tree.def
8541 documentation for TEMPLATE_ID_EXPR. */
8543 tree
8545 {
8546 tree type;
8554 {
8557 }
8560 {
8562 unknown_type_node,
8564 arglist);
8566 }
8573 }
8575 /* Within the scope of a template class S<T>, the name S gets bound
8576 (in build_self_reference) to a TYPE_DECL for the class, not a
8577 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
8578 or one of its enclosing classes, and that type is a template,
8579 return the associated TEMPLATE_DECL. Otherwise, the original
8580 DECL is returned.
8582 Also handle the case when DECL is a TREE_LIST of ambiguous
8583 injected-class-names from different bases. */
8585 tree
8587 {
8591 /* DR 176: A lookup that finds an injected-class-name (10.2
8592 [class.member.lookup]) can result in an ambiguity in certain cases
8593 (for example, if it is found in more than one base class). If all of
8594 the injected-class-names that are found refer to specializations of
8595 the same class template, and if the name is followed by a
8596 template-argument-list, the reference refers to the class template
8597 itself and not a specialization thereof, and is not ambiguous. */
8599 {
8602 {
8608 }
8611 else
8613 }
8619 }
8621 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
8622 parameters, find the desired type.
8624 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
8626 IN_DECL, if non-NULL, is the template declaration we are trying to
8627 instantiate.
8629 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
8630 the class we are looking up.
8632 Issue error and warning messages under control of COMPLAIN.
8634 If the template class is really a local class in a template
8635 function, then the FUNCTION_CONTEXT is the function in which it is
8636 being instantiated.
8638 ??? Note that this function is currently called *twice* for each
8639 template-id: the first time from the parser, while creating the
8640 incomplete type (finish_template_type), and the second type during the
8641 real instantiation (instantiate_template_class). This is surely something
8642 that we want to avoid. It also causes some problems with argument
8643 coercion (see convert_nontype_argument for more information on this). */
8645 static tree
8648 {
8650 tree t;
8653 spec_entry elt;
8654 hashval_t hash;
8657 {
8661 else
8662 {
8669 }
8672 }
8674 {
8677 /* If we are declaring a constructor, say A<T>::A<T>, we will get
8678 an implicit typename for the second A. Deal with it. */
8683 {
8686 }
8687 }
8690 {
8693 }
8695 {
8699 }
8701 {
8704 }
8706 /* Issue an error message if we didn't find a template. */
8708 {
8712 }
8715 /* Make sure it's a user visible template, if it was named by
8716 the user. */
8719 {
8721 {
8725 }
8727 }
8731 /* An alias that just changes the name of a template is equivalent to the
8732 other template, so if any of the arguments are pack expansions, strip
8733 the alias to avoid problems with a pack expansion passed to a non-pack
8734 alias template parameter (DR 1430). */
8739 {
8740 tree parm;
8749 }
8750 else
8751 {
8753 tree gen_tmpl;
8754 tree type_decl;
8762 /* An error occurred while building the template TEMPL, and a
8763 diagnostic has most certainly been emitted for that
8764 already. Let's propagate that error. */
8773 {
8774 /* We've been given an incomplete set of template arguments.
8775 For example, given:
8777 template <class T> struct S1 {
8778 template <class U> struct S2 {};
8779 template <class U> struct S2<U*> {};
8780 };
8782 we will be called with an ARGLIST of `U*', but the
8783 TEMPLATE will be `template <class T> template
8784 <class U> struct S1<T>::S2'. We must fill in the missing
8785 arguments. */
8789 }
8791 /* Now we should have enough arguments. */
8794 /* From here on, we're only interested in the most general
8795 template. */
8797 /* Calculate the BOUND_ARGS. These will be the args that are
8798 actually tsubst'd into the definition to create the
8799 instantiation. */
8801 complain,
8806 /* We were unable to bind the arguments. */
8809 /* In the scope of a template class, explicit references to the
8810 template class refer to the type of the template, not any
8811 instantiation of it. For example, in:
8813 template <class T> class C { void f(C<T>); }
8815 the `C<T>' is just the same as `C'. Outside of the
8816 class, however, such a reference is an instantiation. */
8820 {
8825 }
8827 /* If we already have this specialization, return it. */
8837 /* If the the template's constraints are not satisfied,
8838 then we cannot form a valid type.
8840 Note that the check is deferred until after the hash
8841 lookup. This prevents redundant checks on previously
8842 instantiated specializations. */
8844 {
8846 {
8849 }
8851 }
8855 /* If the deduced arguments are invalid, then the binding
8856 failed. */
8860 complain))
8867 {
8872 }
8882 /* Create the type. */
8884 {
8885 /* The user referred to a specialization of an alias
8886 template represented by GEN_TMPL.
8888 [temp.alias]/2 says:
8890 When a template-id refers to the specialization of an
8891 alias template, it is equivalent to the associated
8892 type obtained by substitution of its
8893 template-arguments for the template-parameters in the
8894 type-id of the alias template. */
8897 /* Note that the call above (by indirectly calling
8898 register_specialization in tsubst_decl) registers the
8899 TYPE_DECL representing the specialization of the alias
8900 template. So next time someone substitutes ARGLIST for
8901 the template parms into the alias template (GEN_TMPL),
8902 she'll get that TYPE_DECL back. */
8906 }
8908 {
8910 {
8921 }
8922 else
8923 {
8924 /* We don't want to call start_enum for this type, since
8925 the values for the enumeration constants may involve
8926 template parameters. And, no one should be interested
8927 in the enumeration constants for such a type. */
8930 }
8934 }
8936 {
8942 /* A local class. Make sure the decl gets registered properly. */
8947 /* This instantiation is another name for the primary
8948 template type. Set the TYPE_CANONICAL field
8949 appropriately. */
8952 /* Some of the template arguments require structural
8953 equality testing, so this template class requires
8954 structural equality testing. */
8956 }
8957 else
8960 /* If we called start_enum or pushtag above, this information
8961 will already be set up. */
8963 {
8970 }
8971 else
8975 {
8981 {
8984 }
8985 }
8989 {
8993 {
8994 tree attributes
9002 }
9003 }
9005 /* Let's consider the explicit specialization of a member
9006 of a class template specialization that is implicitly instantiated,
9007 e.g.:
9008 template<class T>
9009 struct S
9010 {
9011 template<class U> struct M {}; //#0
9012 };
9014 template<>
9015 template<>
9016 struct S<int>::M<char> //#1
9017 {
9018 int i;
9019 };
9020 [temp.expl.spec]/4 says this is valid.
9022 In this case, when we write:
9023 S<int>::M<char> m;
9025 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
9026 the one of #0.
9028 When we encounter #1, we want to store the partial instantiation
9029 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
9031 For all cases other than this "explicit specialization of member of a
9032 class template", we just want to store the most general template into
9033 the CLASSTYPE_TI_TEMPLATE of M.
9035 This case of "explicit specialization of member of a class template"
9036 only happens when:
9037 1/ the enclosing class is an instantiation of, and therefore not
9038 the same as, the context of the most general template, and
9039 2/ we aren't looking at the partial instantiation itself, i.e.
9040 the innermost arguments are not the same as the innermost parms of
9041 the most general template.
9043 So it's only when 1/ and 2/ happens that we want to use the partial
9044 instantiation of the member template in lieu of its most general
9045 template. */
9049 /* the enclosing class must be an instantiation... */
9052 {
9056 tree partial_inst_args =
9063 use_partial_inst_tmpl =
9064 /*...and we must not be looking at the partial instantiation
9065 itself. */
9067 partial_inst_args);
9068 }
9071 /* This case is easy; there are no member templates involved. */
9073 else
9074 {
9075 /* This is a full instantiation of a member template. Find
9076 the partial instantiation of which this is an instance. */
9078 /* Temporarily reduce by one the number of levels in the ARGLIST
9079 so as to avoid comparing the last set of arguments. */
9083 /* FOUND is either a proper class type, or an alias
9084 template specialization. In the later case, it's a
9085 TYPE_DECL, resulting from the substituting of arguments
9086 for parameters in the TYPE_DECL of the alias template
9087 done earlier. So be careful while getting the template
9088 of FOUND. */
9090 ? found
9094 }
9096 // Build template info for the new specialization.
9105 /* Note this use of the partial instantiation so we can check it
9106 later in maybe_process_partial_specialization. */
9113 /* Now that the type has been registered on the instantiations
9114 list, we set up the enumerators. Because the enumeration
9115 constants may involve the enumeration type itself, we make
9116 sure to register the type first, and then create the
9117 constants. That way, doing tsubst_expr for the enumeration
9118 constants won't result in recursive calls here; we'll find
9119 the instantiation and exit above. */
9123 /* If the type makes use of template parameters, the
9124 code that generates debugging information will crash. */
9127 /* Possibly limit visibility based on template args. */
9134 }
9135 }
9137 /* Wrapper for lookup_template_class_1. */
9139 tree
9142 {
9143 tree ret;
9149 }
9151 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
9153 tree
9155 {
9156 /* The type of the expression is NULL_TREE since the template-id could refer
9157 to an explicit or partial specialization. */
9160 /* Except that concepts are always bool. */
9163 }
9165 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9167 tree
9169 {
9173 /* We never want to return a VAR_DECL for a variable concept, since they
9174 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
9189 {
9191 {
9194 }
9196 }
9198 /* If a template-id refers to a specialization of a variable
9199 concept, then the expression is true if and only if the
9200 concept's constraints are satisfied by the given template
9201 arguments.
9203 NOTE: This is an extension of Concepts Lite TS that
9204 allows constraints to be used in expressions. */
9206 {
9209 }
9212 }
9214 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
9215 TARGS template args, and instantiate it if it's not dependent. */
9217 tree
9219 tsubst_flags_t complain)
9220 {
9223 {
9226 }
9229 }
9231 \f
9232 struct pair_fn_data
9233 {
9234 tree_fn_t fn;
9235 tree_fn_t any_fn;
9237 /* True when we should also visit template parameters that occur in
9238 non-deduced contexts. */
9241 };
9243 /* Called from for_each_template_parm via walk_tree. */
9245 static tree
9247 {
9254 #define WALK_SUBTREE(NODE) \
9255 do \
9256 { \
9257 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
9258 pfd->include_nondeduced_p, \
9259 pfd->any_fn); \
9260 if (result) goto out; \
9261 } \
9262 while (0)
9272 {
9276 /* Fall through. */
9282 else
9292 /* Since we're not going to walk subtrees, we have to do this
9293 explicitly here. */
9295 /* Fall through. */
9298 /* Check the return type. */
9301 /* Check the parameter types. Since default arguments are not
9302 instantiated until they are needed, the TYPE_ARG_TYPES may
9303 contain expressions that involve template parameters. But,
9304 no-one should be looking at them yet. And, once they're
9305 instantiated, they don't contain template parameters, so
9306 there's no point in looking at them then, either. */
9307 {
9308 tree parm;
9313 /* Since we've already handled the TYPE_ARG_TYPES, we don't
9314 want walk_tree walking into them itself. */
9316 }
9319 {
9323 }
9340 /* Fall through. */
9352 /* Record template parameters such as `T' inside `TT<T>'. */
9354 /* Fall through. */
9366 /* A template template parameter is encountered. */
9370 /* Already substituted template template parameter */
9375 /* A template-id in a TYPENAME_TYPE might be a deduced context after
9376 partial instantiation. */
9388 /* If there's no type, then this thing must be some expression
9389 involving template parameters. */
9411 }
9413 #undef WALK_SUBTREE
9415 /* We didn't find any template parameters we liked. */
9416 out:
9418 }
9420 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9421 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9422 call FN with the parameter and the DATA.
9423 If FN returns nonzero, the iteration is terminated, and
9424 for_each_template_parm returns 1. Otherwise, the iteration
9425 continues. If FN never returns a nonzero value, the value
9426 returned by for_each_template_parm is 0. If FN is NULL, it is
9427 considered to be the function which always returns 1.
9429 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9430 parameters that occur in non-deduced contexts. When false, only
9431 visits those template parameters that can be deduced. */
9433 static tree
9437 tree_fn_t any_fn)
9438 {
9440 tree result;
9442 /* Set up. */
9448 /* Walk the tree. (Conceptually, we would like to walk without
9449 duplicates, but for_each_template_parm_r recursively calls
9450 for_each_template_parm, so we would need to reorganize a fair
9451 bit to use walk_tree_without_duplicates, so we keep our own
9452 visited list.) */
9455 else
9458 for_each_template_parm_r,
9462 /* Clean up. */
9464 {
9467 }
9470 }
9472 /* Returns true if T depends on any template parameter. */
9474 int
9476 {
9506 else
9507 {
9510 }
9515 }
9517 /* Returns true iff current_function_decl is an incompletely instantiated
9518 template. Useful instead of processing_template_decl because the latter
9519 is set to 0 during instantiate_non_dependent_expr. */
9521 bool
9523 {
9532 }
9534 /* Returns true if T depends on any template parameter with level LEVEL. */
9536 bool
9538 {
9541 }
9543 /* Returns true if the signature of DECL depends on any template parameter from
9544 its enclosing class. */
9546 bool
9548 {
9558 template_parm_outer_level,
9568 }
9570 /* Returns TRUE iff INST is an instantiation we don't need to do in an
9571 ill-formed translation unit, i.e. a variable or function that isn't
9572 usable in a constant expression. */
9576 {
9581 }
9583 /* Returns TRUE iff we should refuse to instantiate DECL because it's
9584 neglectable and instantiated from within an erroneous instantiation. */
9586 static bool
9588 {
9599 }
9607 /* We're starting to instantiate D; record the template instantiation context
9608 for diagnostics and to restore it later. */
9610 bool
9612 {
9614 }
9616 /* We're starting to instantiate D; record the template instantiation context
9617 at LOC for diagnostics and to restore it later. */
9619 bool
9621 {
9625 {
9626 /* Tell error.c not to try to instantiate any templates. */
9629 "template instantiation depth exceeds maximum of %d"
9631 max_tinst_depth);
9633 }
9635 /* If the current instantiation caused problems, don't let it instantiate
9636 anything else. Do allow deduction substitution and decls usable in
9637 constant expressions. */
9641 /* When not -quiet, dump template instantiations other than functions, since
9642 announce_function will take care of those. */
9661 }
9663 /* We're done instantiating this template; return to the instantiation
9664 context. */
9666 void
9668 {
9669 /* Restore the filename and line number stashed away when we started
9670 this instantiation. */
9674 }
9676 /* We're instantiating a deferred template; restore the template
9677 instantiation context in which the instantiation was requested, which
9678 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
9680 static tree
9682 {
9694 }
9696 /* Returns the TINST_LEVEL which gives the original instantiation
9697 context. */
9701 {
9707 }
9709 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
9710 vector of template arguments, as for tsubst.
9712 Returns an appropriate tsubst'd friend declaration. */
9714 static tree
9716 {
9717 tree new_friend;
9722 /* This was a friend declared with an explicit template
9723 argument list, e.g.:
9725 friend void f<>(T);
9727 to indicate that f was a template instantiation, not a new
9728 function declaration. Now, we have to figure out what
9729 instantiation of what template. */
9730 {
9732 tree new_args;
9733 tree tmpl;
9736 /* Friend functions are looked up in the containing namespace scope.
9737 We must enter that scope, to avoid finding member functions of the
9738 current class with same name. */
9753 tsk_none);
9755 }
9759 /* The NEW_FRIEND will look like an instantiation, to the
9760 compiler, but is not an instantiation from the point of view of
9761 the language. For example, we might have had:
9763 template <class T> struct S {
9764 template <class U> friend void f(T, U);
9765 };
9767 Then, in S<int>, template <class U> void f(int, U) is not an
9768 instantiation of anything. */
9774 {
9778 }
9780 /* The mangled name for the NEW_FRIEND is incorrect. The function
9781 is not a template instantiation and should not be mangled like
9782 one. Therefore, we forget the mangling here; we'll recompute it
9783 later if we need it. */
9785 {
9788 }
9791 {
9792 tree old_decl;
9793 tree new_friend_template_info;
9794 tree new_friend_result_template_info;
9795 tree ns;
9798 /* We must save some information from NEW_FRIEND before calling
9799 duplicate decls since that function will free NEW_FRIEND if
9800 possible. */
9802 new_friend_is_defn =
9807 {
9808 /* This declaration is a `primary' template. */
9811 new_friend_result_template_info
9813 }
9814 else
9817 /* Inside pushdecl_namespace_level, we will push into the
9818 current namespace. However, the friend function should go
9819 into the namespace of the template. */
9829 {
9830 /* This new friend declaration matched an existing
9831 declaration. For example, given:
9833 template <class T> void f(T);
9834 template <class U> class C {
9835 template <class T> friend void f(T) {}
9836 };
9838 the friend declaration actually provides the definition
9839 of `f', once C has been instantiated for some type. So,
9840 old_decl will be the out-of-class template declaration,
9841 while new_friend is the in-class definition.
9843 But, if `f' was called before this point, the
9844 instantiation of `f' will have DECL_TI_ARGS corresponding
9845 to `T' but not to `U', references to which might appear
9846 in the definition of `f'. Previously, the most general
9847 template for an instantiation of `f' was the out-of-class
9848 version; now it is the in-class version. Therefore, we
9849 run through all specialization of `f', adding to their
9850 DECL_TI_ARGS appropriately. In particular, they need a
9851 new set of outer arguments, corresponding to the
9852 arguments for this class instantiation.
9854 The same situation can arise with something like this:
9856 friend void f(int);
9857 template <class T> class C {
9858 friend void f(T) {}
9859 };
9861 when `C<int>' is instantiated. Now, `f(int)' is defined
9862 in the class. */
9865 /* On the other hand, if the in-class declaration does
9866 *not* provide a definition, then we don't want to alter
9867 existing definitions. We can just leave everything
9868 alone. */
9869 ;
9870 else
9871 {
9875 /* Overwrite whatever template info was there before, if
9876 any, with the new template information pertaining to
9877 the declaration. */
9881 {
9882 /* We should have called reregister_specialization in
9883 duplicate_decls. */
9888 /* Instantiate it if the global has already been used. */
9892 }
9893 else
9894 {
9895 tree t;
9897 /* Indicate that the old function template is a partial
9898 instantiation. */
9906 /* Reassign any specializations already in the hash table
9907 to the new more general template, and add the
9908 additional template args. */
9912 {
9914 spec_entry elt;
9926 register_specialization
9929 }
9931 }
9932 }
9934 /* The information from NEW_FRIEND has been merged into OLD_DECL
9935 by duplicate_decls. */
9937 }
9938 }
9939 else
9940 {
9944 /* In the code
9945 template <class T> class C {
9946 template <class U> friend void C1<U>::f (); // case 1
9947 friend void C2<T>::f (); // case 2
9948 };
9949 we only need to make sure CONTEXT is a complete type for
9950 case 2. To distinguish between the two cases, we note that
9951 CONTEXT of case 1 remains dependent type after tsubst while
9952 this isn't true for case 2. */
9962 {
9964 /* do_friend adds the TEMPLATE_DECL for any member friend
9965 template even if it isn't a member template, i.e.
9966 template <class T> friend A<T>::f();
9967 Look through it in that case. */
9971 /* Check to see that the declaration is really present, and,
9972 possibly obtain an improved declaration. */
9977 }
9978 }
9981 }
9983 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
9984 template arguments, as for tsubst.
9986 Returns an appropriate tsubst'd friend type or error_mark_node on
9987 failure. */
9989 static tree
9991 {
9992 tree friend_type;
9993 tree tmpl;
9994 tree context;
9997 {
10000 }
10005 {
10008 else
10010 }
10012 /* Look for a class template declaration. We look for hidden names
10013 because two friend declarations of the same template are the
10014 same. For example, in:
10016 struct A {
10017 template <typename> friend class F;
10018 };
10019 template <typename> struct B {
10020 template <typename> friend class F;
10021 };
10023 both F templates are the same. */
10027 /* But, if we don't find one, it might be because we're in a
10028 situation like this:
10030 template <class T>
10031 struct S {
10032 template <class U>
10033 friend struct S;
10034 };
10036 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
10037 for `S<int>', not the TEMPLATE_DECL. */
10039 {
10042 }
10045 {
10046 /* The friend template has already been declared. Just
10047 check to see that the declarations match, and install any new
10048 default parameters. We must tsubst the default parameters,
10049 of course. We only need the innermost template parameters
10050 because that is all that redeclare_class_template will look
10051 at. */
10054 {
10055 tree parms;
10056 location_t saved_input_location;
10066 }
10069 }
10070 else
10071 {
10072 /* The friend template has not already been declared. In this
10073 case, the instantiation of the template class will cause the
10074 injection of this template into the global scope. */
10079 /* The new TMPL is not an instantiation of anything, so we
10080 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
10081 the new type because that is supposed to be the corresponding
10082 template decl, i.e., TMPL. */
10089 /* Inject this template into the global scope. */
10091 }
10094 {
10097 else
10099 }
10102 }
10104 /* Returns zero if TYPE cannot be completed later due to circularity.
10105 Otherwise returns one. */
10107 static int
10109 {
10119 else
10121 }
10126 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
10127 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
10129 static tree
10132 {
10141 {
10148 clauses
10152 else
10154 }
10155 /* If the first attribute argument is an identifier, don't
10156 pass it through tsubst. Attributes like mode, format,
10157 cleanup and several target specific attributes expect it
10158 unmodified. */
10160 {
10161 tree chain
10166 }
10168 {
10169 /* An attribute pack expansion. */
10178 {
10182 }
10184 }
10185 else
10192 }
10194 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
10195 unchanged or a new TREE_LIST chain. */
10197 static tree
10200 {
10205 {
10209 }
10213 {
10216 {
10219 {
10221 do
10226 }
10227 }
10229 }
10232 }
10234 /* Apply any attributes which had to be deferred until instantiation
10235 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
10236 ARGS, COMPLAIN, IN_DECL are as tsubst. */
10238 static void
10241 {
10243 tree t;
10250 {
10254 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
10255 to our attributes parameter. */
10257 }
10258 else
10259 {
10261 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
10262 lookup_template_class_1, and should be preserved. */
10266 }
10270 {
10274 }
10278 {
10283 {
10286 {
10290 do
10293 }
10294 else
10296 }
10299 }
10300 }
10302 /* Perform (or defer) access check for typedefs that were referenced
10303 from within the template TMPL code.
10304 This is a subroutine of instantiate_decl and instantiate_class_template.
10305 TMPL is the template to consider and TARGS is the list of arguments of
10306 that template. */
10308 static void
10310 {
10311 location_t saved_location;
10322 {
10334 /* Make access check error messages point to the location
10335 of the use of the typedef. */
10339 tf_warning_or_error);
10340 }
10342 }
10344 static tree
10346 {
10348 tree typedecl;
10349 tree pbinfo;
10350 tree base_list;
10352 tree fn_context;
10361 /* Figure out which template is being instantiated. */
10365 /* Determine what specialization of the original template to
10366 instantiate. */
10369 {
10372 }
10374 {
10375 /* This TYPE is actually an instantiation of a partial
10376 specialization. We replace the innermost set of ARGS with
10377 the arguments appropriate for substitution. For example,
10378 given:
10380 template <class T> struct S {};
10381 template <class T> struct S<T*> {};
10383 and supposing that we are instantiating S<int*>, ARGS will
10384 presently be {int*} -- but we need {int}. */
10387 }
10388 else
10389 {
10392 }
10394 /* If the template we're instantiating is incomplete, then clearly
10395 there's nothing we can do. */
10399 /* If we've recursively instantiated too many templates, stop. */
10403 /* Now we're really doing the instantiation. Mark the type as in
10404 the process of being defined. */
10407 /* We may be in the middle of deferred access check. Disable
10408 it now. */
10415 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10420 else
10421 {
10424 }
10425 /* Use #pragma pack from the template context. */
10431 /* Set the input location to the most specialized template definition.
10432 This is needed if tsubsting causes an error. */
10444 {
10447 /* Adjust visibility for template arguments. */
10449 }
10455 /* We should never instantiate a nested class before its enclosing
10456 class; we need to look up the nested class by name before we can
10457 instantiate it, and that lookup should instantiate the enclosing
10458 class. */
10464 {
10465 tree pbase_binfo;
10466 tree pushed_scope;
10469 /* We must enter the scope containing the type, as that is where
10470 the accessibility of types named in dependent bases are
10471 looked up from. */
10474 /* Substitute into each of the bases to determine the actual
10475 basetypes. */
10477 {
10478 tree base;
10484 {
10485 expanded_bases =
10492 }
10495 {
10497 /* Extract the already-expanded base class. */
10499 else
10500 /* Substitute to figure out the base class. */
10502 NULL_TREE);
10510 }
10511 }
10513 /* The list is now in reverse order; correct that. */
10518 }
10519 /* Now call xref_basetypes to set up all the base-class
10520 information. */
10528 /* Now that our base classes are set up, enter the scope of the
10529 class, so that name lookups into base classes, etc. will work
10530 correctly. This is precisely analogous to what we do in
10531 begin_class_definition when defining an ordinary non-template
10532 class, except we also need to push the enclosing classes. */
10535 /* Now members are processed in the order of declaration. */
10538 {
10542 {
10544 {
10545 /* Build new CLASSTYPE_NESTED_UTDS. */
10547 tree newtag;
10553 /* If the member is a class template, then -- even after
10554 substitution -- there may be dependent types in the
10555 template argument list for the class. We increment
10556 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
10557 that function will assume that no types are dependent
10558 when outside of a template. */
10568 {
10572 /* Unfortunately, lookup_template_class sets
10573 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
10574 instantiation (i.e., for the type of a member
10575 template class nested within a template class.)
10576 This behavior is required for
10577 maybe_process_partial_specialization to work
10578 correctly, but is not accurate in this case;
10579 the TAG is not an instantiation of anything.
10580 (The corresponding TEMPLATE_DECL is an
10581 instantiation, but the TYPE is not.) */
10584 /* Now, we call pushtag to put this NEWTAG into the scope of
10585 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
10586 pushtag calling push_template_decl. We don't have to do
10587 this for enums because it will already have been done in
10588 tsubst_enum. */
10592 }
10593 }
10595 {
10596 tree r;
10605 /* Instantiate members marked with attribute used. */
10611 }
10614 /* A closure type for a lambda in a default argument for a
10615 member template. Ignore it; it will be instantiated with
10617 else
10618 {
10619 /* Build new TYPE_FIELDS. */
10621 {
10622 tree condition;
10625 condition =
10635 }
10637 {
10638 tree r;
10642 /* The file and line for this declaration, to
10643 assist in error message reporting. Since we
10644 called push_tinst_level above, we don't need to
10645 restore these. */
10655 {
10656 /* A capture pack became multiple fields. */
10659 }
10662 {
10666 {
10667 /* In [temp.inst]:
10669 [t]he initialization (and any associated
10670 side-effects) of a static data member does
10671 not occur unless the static data member is
10672 itself used in a way that requires the
10673 definition of the static data member to
10674 exist.
10676 Therefore, we do not substitute into the
10677 initialized for the static data member here. */
10678 finish_static_data_member_decl
10684 /* Instantiate members marked with attribute used. */
10687 }
10689 {
10690 /* Determine whether R has a valid type and can be
10691 completed later. If R is invalid, then its type
10692 is replaced by error_mark_node. */
10698 {
10699 /* If R's type couldn't be completed and
10700 it isn't a flexible array member (whose
10701 type is incomplete by definition) give
10702 an error. */
10705 }
10706 }
10708 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10709 such a thing will already have been added to the field
10710 list by tsubst_enum in finish_member_declaration in the
10711 CLASSTYPE_NESTED_UTDS case above. */
10715 {
10718 }
10719 }
10720 }
10721 }
10722 }
10723 else
10724 {
10727 {
10728 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10734 {
10735 /* template <class T> friend class C; */
10738 }
10740 {
10741 /* template <class T> friend class C::D; */
10747 }
10750 {
10751 /* This could be either
10753 friend class T::C;
10755 when dependent_type_p is false or
10757 template <class U> friend class T::C;
10759 otherwise. */
10760 /* Bump processing_template_decl in case this is something like
10761 template <class T> friend struct A<T>::B. */
10768 }
10772 {
10773 /* friend class C;
10775 where C hasn't been declared yet. Let's lookup name
10776 from namespace scope directly, bypassing any name that
10777 come from dependent base class. */
10780 /* The call to xref_tag_from_type does injection for friend
10781 classes. */
10783 friend_type =
10787 }
10789 /* friend class C<T>; */
10792 /* Otherwise it's
10794 friend class C;
10796 where C is already declared or
10798 friend class C<int>;
10800 We don't have to do anything in these cases. */
10803 /* Trick make_friend_class into realizing that the friend
10804 we're adding is a template, not an ordinary class. It's
10805 important that we use make_friend_class since it will
10806 perform some error-checking and output cross-reference
10807 information. */
10815 }
10816 else
10817 {
10818 /* Build new DECL_FRIENDLIST. */
10819 tree r;
10821 /* The file and line for this declaration, to
10822 assist in error message reporting. Since we
10823 called push_tinst_level above, we don't need to
10824 restore these. */
10828 {
10831 }
10836 {
10839 }
10840 }
10841 }
10842 }
10845 {
10846 /* Restore these before substituting into the lambda capture
10847 initializers. */
10850 }
10853 {
10856 {
10862 {
10863 /* Set function_depth to avoid garbage collection. */
10867 }
10869 /* We need to instantiate the capture list from the template
10870 after we've instantiated the closure members, but before we
10871 consider adding the conversion op. Also keep any captures
10872 that may have been added during instantiation of the op(). */
10874 tree tmpl_cap
10883 }
10884 else
10886 }
10888 /* Set the file and line number information to whatever is given for
10889 the class itself. This puts error messages involving generated
10890 implicit functions at a predictable point, and the same point
10891 that would be used for non-template classes. */
10898 /* We don't instantiate default arguments for member functions. 14.7.1:
10900 The implicit instantiation of a class template specialization causes
10901 the implicit instantiation of the declarations, but not of the
10902 definitions or default arguments, of the class member functions,
10903 member classes, static data members and member templates.... */
10905 /* Some typedefs referenced from within the template code need to be access
10906 checked at template instantiation time, i.e now. These types were
10907 added to the template at parsing time. Let's get those and perform
10908 the access checks then. */
10918 /* The vtable for a template class can be emitted in any translation
10919 unit in which the class is instantiated. When there is no key
10920 method, however, finish_struct_1 will already have added TYPE to
10921 the keyed_classes. */
10926 }
10928 /* Wrapper for instantiate_class_template_1. */
10930 tree
10932 {
10933 tree ret;
10938 }
10940 static tree
10942 {
10943 tree r;
10949 else
10950 {
10957 }
10959 }
10961 /* Given a function parameter pack TMPL_PARM and some function parameters
10962 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
10963 and set *SPEC_P to point at the next point in the list. */
10965 tree
10967 {
10968 /* Collect all of the extra "packed" parameters into an
10969 argument pack. */
10970 tree parmvec;
10980 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
10986 /* Build the argument packs. */
10991 }
10993 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
10994 NONTYPE_ARGUMENT_PACK. */
10996 static tree
10998 {
11000 }
11002 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
11003 pack expansion with no extra args, 2 if it has extra args, or 0
11004 if it is not a pack expansion. */
11006 static int
11008 {
11014 /* A decl pack is itself an expansion. */
11021 }
11024 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
11026 static tree
11028 {
11035 }
11037 /* This is a subroutine of tsubst_pack_expansion.
11039 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
11040 mechanism to store the (non complete list of) arguments of the
11041 substitution and return a non substituted pack expansion, in order
11042 to wait for when we have enough arguments to really perform the
11043 substitution. */
11045 static bool
11049 {
11050 /* If one pack has an expansion and another pack has a normal
11051 argument or if one pack has an empty argument and an another
11052 one hasn't then tsubst_pack_expansion cannot perform the
11053 substitution and need to fall back on the
11054 PACK_EXPANSION_EXTRA mechanism. */
11062 {
11065 parm_pack;
11067 {
11072 /* We can't substitute a pack expansion with extra args into
11073 our pattern. */
11077 else
11079 }
11083 }
11085 }
11087 /* [temp.variadic]/6 says that:
11089 The instantiation of a pack expansion [...]
11090 produces a list E1,E2, ..., En, where N is the number of elements
11091 in the pack expansion parameters.
11093 This subroutine of tsubst_pack_expansion produces one of these Ei.
11095 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
11096 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
11097 PATTERN, and each TREE_VALUE is its corresponding argument pack.
11098 INDEX is the index 'i' of the element Ei to produce. ARGS,
11099 COMPLAIN, and IN_DECL are the same parameters as for the
11100 tsubst_pack_expansion function.
11102 The function returns the resulting Ei upon successful completion,
11103 or error_mark_node.
11105 Note that this function possibly modifies the ARGS parameter, so
11106 it's the responsibility of the caller to restore it. */
11108 static tree
11110 tree parm_packs,
11112 tree args /* This parm gets
11114 tsubst_flags_t complain,
11115 tree in_decl)
11116 {
11117 tree t;
11120 /* For each parameter pack, change the substitution of the parameter
11121 pack to the ith argument in its argument pack, then expand the
11122 pattern. */
11124 {
11129 ith_elem_is_expansion |=
11132 /* Select the Ith argument from the pack. */
11135 {
11137 {
11142 }
11143 else
11145 }
11146 else
11147 {
11152 {
11154 /* Update the corresponding argument. */
11156 }
11157 else
11158 /* Re-use the ARGUMENT_PACK_SELECT. */
11160 }
11162 }
11164 /* Substitute into the PATTERN with the (possibly altered)
11165 arguments. */
11167 /* Expanding a fixed parameter pack from
11168 coerce_template_parameter_pack. */
11173 {
11176 else
11179 }
11183 else
11186 /* If the Ith argument pack element is a pack expansion, then
11187 the Ith element resulting from the substituting is going to
11188 be a pack expansion as well. */
11193 }
11195 /* When the unexpanded parameter pack in a fold expression expands to an empty
11196 sequence, the value of the expression is as follows; the program is
11197 ill-formed if the operator is not listed in this table.
11199 && true
11200 || false
11201 , void() */
11203 tree
11205 {
11209 {
11218 }
11224 }
11226 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11227 form an expression that combines the two terms using the
11228 operator of T. */
11230 static tree
11232 {
11236 // Handle compound assignment operators.
11241 {
11251 complain);
11252 }
11253 }
11255 /* Substitute ARGS into the pack of a fold expression T. */
11259 {
11261 }
11263 /* Substitute ARGS into the pack of a fold expression T. */
11267 {
11269 }
11271 /* Expand a PACK of arguments into a grouped as left fold.
11272 Given a pack containing elements A0, A1, ..., An and an
11273 operator @, this builds the expression:
11275 ((A0 @ A1) @ A2) ... @ An
11277 Note that PACK must not be empty.
11279 The operator is defined by the original fold expression T. */
11281 static tree
11283 {
11286 {
11289 }
11291 }
11293 /* Substitute into a unary left fold expression. */
11295 static tree
11297 tree in_decl)
11298 {
11303 {
11307 }
11310 else
11312 }
11314 /* Substitute into a binary left fold expression.
11316 Do ths by building a single (non-empty) vector of argumnts and
11317 building the expression from those elements. */
11319 static tree
11321 tree in_decl)
11322 {
11331 {
11336 }
11344 }
11346 /* Expand a PACK of arguments into a grouped as right fold.
11347 Given a pack containing elementns A0, A1, ..., and an
11348 operator @, this builds the expression:
11350 A0@ ... (An-2 @ (An-1 @ An))
11352 Note that PACK must not be empty.
11354 The operator is defined by the original fold expression T. */
11356 tree
11358 {
11359 // Build the expression.
11363 {
11366 }
11368 }
11370 /* Substitute into a unary right fold expression. */
11372 static tree
11374 tree in_decl)
11375 {
11380 {
11384 }
11387 else
11389 }
11391 /* Substitute into a binary right fold expression.
11393 Do ths by building a single (non-empty) vector of arguments and
11394 building the expression from those elements. */
11396 static tree
11398 tree in_decl)
11399 {
11408 {
11413 }
11422 }
11425 /* Substitute ARGS into T, which is an pack expansion
11426 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
11427 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
11428 (if only a partial substitution could be performed) or
11429 ERROR_MARK_NODE if there was an error. */
11430 tree
11432 tree in_decl)
11433 {
11434 tree pattern;
11438 tree result;
11446 /* Add in any args remembered from an earlier partial instantiation. */
11451 /* Determine the argument packs that will instantiate the parameter
11452 packs used in the expansion expression. While we're at it,
11453 compute the number of arguments to be expanded and make sure it
11454 is consistent. */
11457 {
11464 {
11469 else
11472 }
11474 {
11475 /* ??? Support use in other patterns. */
11479 }
11481 {
11482 /* We know we have correct local_specializations if this
11483 expansion is at function scope, or if we're dealing with a
11484 local parameter in a requires expression; for the latter,
11485 tsubst_requires_expr set it up appropriately. */
11488 else
11489 /* We can't rely on local_specializations for a parameter
11490 name used later in a function declaration (such as in a
11491 late-specified return type). Even if it exists, it might
11492 have the wrong value for a recursive call. */
11496 {
11497 /* This parameter pack was used in an unevaluated context. Just
11498 make a dummy decl, since it's only used for its type. */
11501 /* Partial instantiation of the parm_pack, we can't build
11502 up an argument pack yet. */
11504 else
11506 }
11507 }
11510 else
11511 {
11517 }
11524 /* This can only happen if we forget to expand an argument
11525 pack somewhere else. Just return an error, silently. */
11526 {
11530 }
11533 {
11537 /* Don't bother trying to do a partial substitution with
11538 incomplete packs; we'll try again after deduction. */
11545 {
11550 pattern);
11551 else
11553 pattern);
11555 }
11557 /* Keep track of the parameter packs and their corresponding
11558 argument packs. */
11561 }
11562 else
11563 {
11564 /* We can't substitute for this parameter pack. We use a flag as
11565 well as the missing_level counter because function parameter
11566 packs don't have a level. */
11569 }
11570 }
11572 /* If the expansion is just T..., return the matching argument pack, unless
11573 we need to call convert_from_reference on all the elements. This is an
11574 important optimization; see c++/68422. */
11577 {
11579 /* Types need no adjustment, nor does sizeof..., and if we still have
11580 some pack expansion args we won't do anything yet. */
11585 /* Also optimize expression pack expansions if we can tell that the
11586 elements won't have reference type. */
11592 /* Otherwise use the normal path so we get convert_from_reference. */
11593 }
11595 /* We cannot expand this expansion expression, because we don't have
11596 all of the argument packs we need. */
11598 {
11599 /* We got some full packs, but we can't substitute them in until we
11600 have values for all the packs. So remember these until then. */
11605 }
11607 {
11608 /* There were no real arguments, we're just replacing a parameter
11609 pack with another version of itself. Substitute into the
11610 pattern and return a PACK_EXPANSION_*. The caller will need to
11611 deal with that. */
11615 else
11619 }
11624 {
11625 /* We're in a late-specified return type, so create our own local
11626 specializations map; the current map is either NULL or (in the
11627 case of recursive unification) might have bindings that we don't
11628 want to use or alter. */
11631 }
11633 /* For each argument in each argument pack, substitute into the
11634 pattern. */
11638 {
11640 i,
11642 in_decl);
11645 {
11648 }
11649 }
11651 /* Update ARGS to restore the substitution from parameter packs to
11652 their argument packs. */
11654 {
11660 else
11661 {
11669 /* Update the corresponding argument. */
11673 else
11675 }
11676 }
11679 {
11682 }
11684 /* If the dependent pack arguments were such that we end up with only a
11685 single pack expansion again, there's no need to keep it in a TREE_VEC. */
11691 }
11693 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
11694 TMPL. We do this using DECL_PARM_INDEX, which should work even with
11695 parameter packs; all parms generated from a function parameter pack will
11696 have the same DECL_PARM_INDEX. */
11698 tree
11700 {
11702 tree patparm;
11705 {
11711 }
11712 else
11713 {
11718 }
11721 }
11723 /* Make an argument pack out of the TREE_VEC VEC. */
11725 static tree
11727 {
11728 tree pack;
11732 else
11733 {
11736 }
11739 }
11741 /* Return an exact copy of template args T that can be modified
11742 independently. */
11744 static tree
11746 {
11754 {
11759 }
11765 }
11767 /* Substitute ARGS into the vector or list of template arguments T. */
11769 static tree
11771 {
11783 {
11785 tree new_arg;
11790 {
11791 /* Substitute into an expansion expression. */
11795 /* Add to the expanded length adjustment the number of
11796 expanded arguments. We subtract one from this
11797 measurement, because the argument pack expression
11798 itself is already counted as 1 in
11799 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
11800 the argument pack is empty. */
11802 }
11804 {
11805 /* Substitute into each of the arguments. */
11814 else
11819 }
11820 else
11829 }
11834 /* Make space for the expanded arguments coming from template
11835 argument packs. */
11837 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
11838 arguments for a member template.
11839 In that case each TREE_VEC in ORIG_T represents a level of template
11840 arguments, and ORIG_T won't carry any non defaulted argument count.
11841 It will rather be the nested TREE_VECs that will carry one.
11842 In other words, ORIG_T carries a non defaulted argument count only
11843 if it doesn't contain any nested TREE_VEC. */
11845 {
11849 }
11851 {
11855 {
11858 /* Now expand the template argument pack "in place". */
11861 }
11862 else
11863 {
11865 out++;
11866 }
11867 }
11870 }
11872 /* Substitute ARGS into one level PARMS of template parameters. */
11874 static tree
11876 {
11883 {
11891 }
11894 }
11896 /* Return the result of substituting ARGS into the template parameters
11897 given by PARMS. If there are m levels of ARGS and m + n levels of
11898 PARMS, then the result will contain n levels of PARMS. For
11899 example, if PARMS is `template <class T> template <class U>
11900 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
11901 result will be `template <int*, double, class V>'. */
11903 static tree
11905 {
11909 /* When substituting into a template, we must set
11910 PROCESSING_TEMPLATE_DECL as the template parameters may be
11911 dependent if they are based on one-another, and the dependency
11912 predicates are short-circuit outside of templates. */
11919 {
11926 }
11931 }
11933 /* Return the result of substituting ARGS into one template parameter
11934 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
11935 parameter and which TREE_PURPOSE is the default argument of the
11936 template parameter. */
11938 static tree
11940 {
11961 }
11963 /* Substitute the ARGS into the indicated aggregate (or enumeration)
11964 type T. If T is not an aggregate or enumeration type, it is
11965 handled as if by tsubst. IN_DECL is as for tsubst. If
11966 ENTERING_SCOPE is nonzero, T is the context for a template which
11967 we are presently tsubst'ing. Return the substituted value. */
11969 static tree
11971 tree args,
11972 tsubst_flags_t complain,
11973 tree in_decl,
11975 {
11980 {
11985 /* Fall through. */
11989 {
11990 tree argvec;
11991 tree context;
11992 tree r;
11996 /* In "sizeof(X<I>)" we need to evaluate "I". */
12002 /* First, determine the context for the type we are looking
12003 up. */
12006 {
12009 /* If context is a nested class inside a class template,
12010 it may still need to be instantiated (c++/33959). */
12012 }
12014 /* Then, figure out what arguments are appropriate for the
12015 type we are trying to find. For example, given:
12017 template <class T> struct S;
12018 template <class T, class U> void f(T, U) { S<U> su; }
12020 and supposing that we are instantiating f<int, double>,
12021 then our ARGS will be {int, double}, but, when looking up
12022 S we only want {double}. */
12027 else
12028 {
12032 }
12038 }
12039 else
12040 /* This is not a template type, so there's nothing to do. */
12045 }
12046 }
12050 /* Substitute into the default argument ARG (a default argument for
12051 FN), which has the indicated TYPE. */
12053 tree
12055 tsubst_flags_t complain)
12056 {
12061 /* This can happen in invalid code. */
12076 /* This default argument came from a template. Instantiate the
12077 default argument here, not in tsubst. In the case of
12078 something like:
12080 template <class T>
12081 struct S {
12082 static T t();
12083 void f(T = t());
12084 };
12086 we must be careful to do name lookup in the scope of S<T>,
12087 rather than in the current class. */
12089 /* The "this" pointer is not valid in a default argument. */
12091 {
12096 }
12101 /* The default argument expression may cause implicitly defined
12102 member functions to be synthesized, which will result in garbage
12103 collection. We must treat this situation as if we were within
12104 the body of function so as to avoid collecting live data on the
12105 stack. */
12115 /* Restore the "this" pointer. */
12117 {
12120 }
12127 /* Make sure the default argument is reasonable. */
12133 {
12137 }
12140 }
12142 /* Substitute into all the default arguments for FN. */
12144 static void
12146 {
12147 tree arg;
12148 tree tmpl_args;
12152 /* If this function is not yet instantiated, we certainly don't need
12153 its default arguments. */
12156 /* Don't do this again for clones. */
12162 arg;
12168 complain);
12169 }
12171 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
12173 static tree
12175 tree lambda_fntype)
12176 {
12181 /* Nobody should be tsubst'ing into non-template functions. */
12185 {
12186 /* If T is not dependent, just return it. */
12190 /* Calculate the most general template of which R is a
12191 specialization, and the complete set of arguments used to
12192 specialize R. */
12195 (DECL_TEMPLATE_RESULT
12201 /* Check to see if we already have this specialization. */
12203 {
12207 }
12209 /* We can see more levels of arguments than parameters if
12210 there was a specialization of a member template, like
12211 this:
12213 template <class T> struct S { template <class U> void f(); }
12214 template <> template <class U> void S<int>::f(U);
12216 Here, we'll be substituting into the specialization,
12217 because that's where we can find the code we actually
12218 want to generate, but we'll have enough arguments for
12219 the most general template.
12221 We also deal with the peculiar case:
12223 template <class T> struct S {
12224 template <class U> friend void f();
12225 };
12226 template <class U> void f() {}
12227 template S<int>;
12228 template void f<double>();
12230 Here, the ARGS for the instantiation of will be {int,
12231 double}. But, we only need as many ARGS as there are
12232 levels of template parameters in CODE_PATTERN. We are
12233 careful not to get fooled into reducing the ARGS in
12234 situations like:
12236 template <class T> struct S { template <class U> void f(U); }
12237 template <class T> template <> void S<T>::f(int) {}
12239 which we can spot because the pattern will be a
12240 specialization in this case. */
12247 }
12248 else
12249 {
12250 /* This special case arises when we have something like this:
12252 template <class T> struct S {
12253 friend void f<int>(int, double);
12254 };
12256 Here, the DECL_TI_TEMPLATE for the friend declaration
12257 will be an IDENTIFIER_NODE. We are being called from
12258 tsubst_friend_function, and we want only to create a
12259 new decl (R) with appropriate types so that we can call
12260 determine_specialization. */
12263 }
12280 /* If we hit excessive deduction depth, the type is bogus even if
12281 it isn't error_mark_node, so don't build a decl. */
12285 /* We do NOT check for matching decls pushed separately at this
12286 point, as they may not represent instantiations of this
12287 template, and in any case are considered separate under the
12288 discrete model. */
12292 /* Clear out the mangled name and RTL for the instantiation. */
12295 /* Leave DECL_INITIAL set on deleted instantiations. */
12300 /* OpenMP UDRs have the only argument a reference to the declared
12301 type. We want to diagnose if the declared type is a reference,
12302 which is invalid, but as references to references are usually
12303 quietly merged, diagnose it here. */
12305 {
12306 tree argtype
12311 "reference type %qT in "
12315 argtype);
12316 }
12319 /* Type-conversion operator. Reconstruct the name, in
12320 case it's the name of one of the template's parameters. */
12330 {
12334 }
12341 /* If this is an instantiation of a function with internal
12342 linkage, we already know what object file linkage will be
12343 assigned to the instantiation. */
12352 /* We'll re-clone as appropriate in instantiate_template. */
12355 /* If we aren't complaining now, return on error before we register
12356 the specialization so that we'll complain eventually. */
12362 /* When instantiating a constrained member, substitute
12363 into the constraints to create a new constraint. */
12366 {
12369 }
12371 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
12372 this in the special friend case mentioned above where
12373 GEN_TMPL is NULL. */
12375 {
12380 tree new_r
12383 /* We instantiated this while substituting into
12384 the type earlier (template/friend54.C). */
12387 /* We're not supposed to instantiate default arguments
12388 until they are called, for a template. But, for a
12389 declaration like:
12391 template <class T> void f ()
12392 { extern void g(int i = T()); }
12394 we should do the substitution when the template is
12395 instantiated. We handle the member function case in
12396 instantiate_class_template since the default arguments
12397 might refer to other members of the class. */
12402 }
12403 else
12406 /* Copy the list of befriending classes. */
12410 {
12414 }
12417 {
12421 /* If this is an instantiation of a member template, clone it.
12422 If it isn't, that'll be handled by
12423 clone_constructors_and_destructors. */
12426 }
12437 /* Possibly limit visibility based on template args. */
12440 {
12444 }
12453 }
12455 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
12457 static tree
12459 tree lambda_fntype)
12460 {
12461 /* We can get here when processing a member function template,
12462 member class template, or template template parameter. */
12465 tree spec;
12466 tree tmpl_args;
12467 tree full_args;
12468 tree r;
12472 {
12473 /* Template template parameter is treated here. */
12477 /* If we get a real template back, return it. This can happen in
12478 the context of most_specialized_partial_spec. */
12481 else
12482 /* The new TEMPLATE_DECL was built in
12483 reduce_template_parm_level. */
12486 }
12489 {
12490 /* We might already have an instance of this template.
12491 The ARGS are for the surrounding class type, so the
12492 full args contain the tsubst'd args for the context,
12493 plus the innermost args from the template decl. */
12497 /* Because this is a template, the arguments will still be
12498 dependent, even after substitution. If
12499 PROCESSING_TEMPLATE_DECL is not set, the dependency
12500 predicates will short-circuit. */
12508 /* If this is a default template template argument,
12509 tsubst might not have changed anything. */
12517 }
12519 /* Make a new template decl. It will be similar to the
12520 original, but will record the current template arguments.
12521 We also create a new function declaration, which is just
12522 like the old one, but points to this new template, rather
12523 than the old one. */
12528 // Build new template info linking to the original template decl.
12530 {
12533 }
12534 else
12537 /* The template parameters for this new template are all the
12538 template parameters for the old template, except the
12539 outermost level of parameters. */
12542 complain);
12546 {
12547 tree new_type;
12555 /* For a partial specialization, we need to keep pointing to
12556 the primary template. */
12562 }
12563 else
12564 {
12565 tree new_decl;
12569 else
12579 {
12582 }
12583 else
12584 {
12587 }
12588 }
12598 /* Record this non-type partial instantiation. */
12604 }
12606 /* True if FN is the op() for a lambda in an uninstantiated template. */
12608 bool
12610 {
12615 }
12617 /* True if FN is the op() for a lambda regenerated from a lambda in an
12618 uninstantiated template. */
12620 bool
12622 {
12625 }
12627 /* We're instantiating a variable from template function TCTX. Return the
12628 corresponding current enclosing scope. This gets complicated because lambda
12629 functions in templates are regenerated rather than instantiated, but generic
12630 lambda functions are subsequently instantiated. */
12632 static tree
12634 {
12642 {
12653 {
12657 }
12659 }
12661 }
12663 /* Substitute the ARGS into the T, which is a _DECL. Return the
12664 result of the substitution. Issue error and warning messages under
12665 control of COMPLAIN. */
12667 static tree
12669 {
12670 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
12671 location_t saved_loc;
12676 /* Set the filename and linenumber to improve error-reporting. */
12681 {
12691 {
12699 {
12700 /* If there is a local specialization that isn't a
12701 parameter pack, it means that we're doing a "simple"
12702 substitution from inside tsubst_pack_expansion. Just
12703 return the local specialization (which will be a single
12704 parm). */
12711 /* Expand the TYPE_PACK_EXPANSION that provides the types for
12712 the parameters in this function parameter pack. */
12716 {
12719 /* Zero-length parameter packs are boring. Just substitute
12720 into the chain. */
12724 }
12725 else
12726 {
12727 /* All we did was update the type. Make a note of that. */
12730 }
12731 }
12733 /* Loop through all of the parameters we'll build. When T is
12734 a function parameter pack, LEN is the number of expanded
12735 types in EXPANDED_TYPES; otherwise, LEN is 1. */
12738 {
12745 /* We're on the Ith parameter of the function parameter
12746 pack. */
12747 {
12748 /* Get the Ith type. */
12751 /* Rename the parameter to include the index. */
12754 }
12756 /* We're dealing with a normal parameter. */
12764 {
12767 else
12770 }
12780 /* Keep track of the first new parameter we
12781 generate. That's what will be returned to the
12782 caller. */
12786 /* Build a proper chain of parameters when substituting
12787 into a function parameter pack. */
12790 }
12792 /* If cp_unevaluated_operand is set, we're just looking for a
12793 single dummy parameter, so don't keep going. */
12798 /* FIRST_R contains the start of the chain we've built. */
12800 }
12804 {
12811 {
12812 /* This field is a lambda capture pack. Return a TREE_VEC of
12813 the expanded fields to instantiate_class_template_1 and
12814 store them in the specializations hash table as a
12815 NONTYPE_ARGUMENT_PACK so that tsubst_copy can find them. */
12819 {
12822 }
12823 else
12824 {
12825 /* All we did was update the type. Make a note of that. */
12828 }
12829 }
12832 {
12835 {
12839 }
12849 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
12850 number of bits. */
12856 {
12857 /* Set up DECL_TEMPLATE_INFO so that we can get at the
12858 NSDMI in perform_member_init. Still set DECL_INITIAL
12859 so that we know there is one. */
12864 }
12865 /* We don't have to set DECL_CONTEXT here; it is set by
12866 finish_member_declaration. */
12874 }
12877 {
12882 }
12883 }
12887 /* We reach here only for member using decls. We also need to check
12888 uses_template_parms because DECL_DEPENDENT_P is not set for a
12889 using-declaration that designates a member of the current
12890 instantiation (c++/53549). */
12893 {
12897 {
12902 {
12906 {
12909 }
12910 else
12911 {
12914 }
12916 }
12917 }
12918 else
12919 {
12925 else
12926 {
12929 }
12930 }
12931 }
12932 else
12933 {
12936 }
12941 {
12944 tree spec;
12946 tree ctx;
12955 {
12956 /* If this is the canonical decl, we don't have to
12957 mess with instantiations, and often we can't (for
12958 typename, template type parms and such). Note that
12959 TYPE_NAME is not correct for the above test if
12960 we've copied the type for a typedef. */
12966 }
12968 /* Check to see if we already have the specialization we
12969 need. */
12972 {
12973 /* T is a static data member or namespace-scope entity.
12974 We have to substitute into namespace-scope variables
12975 (not just variable templates) because of cases like:
12977 template <class T> void f() { extern T t; }
12979 where the entity referenced is not known until
12980 instantiation time. */
12984 {
12986 complain,
12988 /* If CTX is unchanged, then T is in fact the
12989 specialization we want. That situation occurs when
12990 referencing a static data member within in its own
12991 class. We can use pointer equality, rather than
12992 same_type_p, because DECL_CONTEXT is always
12993 canonical... */
12995 /* ... unless T is a member template; in which
12996 case our caller can be willing to create a
12997 specialization of that template represented
12998 by T. */
13002 }
13005 {
13010 argvec = (coerce_innermost_template_parms
13018 }
13019 }
13020 else
13021 {
13022 /* A local variable. */
13024 /* Subsequent calls to pushdecl will fill this in. */
13026 /* Unless this is a reference to a static variable from an
13027 enclosing function, in which case we need to fill it in now. */
13029 {
13033 }
13035 }
13036 /* If we already have the specialization we need, there is
13037 nothing more to do. */
13039 {
13042 }
13044 /* Create a new node for the specialization we need. */
13047 {
13050 else
13058 {
13059 /* Mask off any template args past the variable's context so we
13060 don't replace the auto with an unrelated argument. */
13064 /* This should never happen with the new lambda instantiation
13065 model, but keep the handling just in case. */
13068 }
13070 }
13072 {
13073 /* Even if the original location is out of scope, the
13074 newly substituted one is not. */
13081 {
13082 /* It may seem that this case cannot occur, since:
13084 typedef void f();
13085 void g() { f x; }
13087 declares a function, not a variable. However:
13089 typedef void f();
13090 template <typename T> void g() { T t; }
13091 template void g<f>();
13093 is an attempt to declare a variable with function
13094 type. */
13096 /* R is not yet sufficiently initialized, so we
13097 just use its name. */
13100 }
13102 /* Wait until cp_finish_decl to set this again, to handle
13103 circular dependency (template/instantiate6.C). */
13108 {
13113 {
13116 }
13118 }
13122 }
13128 /* Clear out the mangled name and RTL for the instantiation. */
13132 /* The initializer must not be expanded until it is required;
13133 see [temp.inst]. */
13137 {
13140 /* Possibly limit visibility based on template args. */
13143 {
13147 }
13149 }
13152 {
13153 /* A static data member declaration is always marked
13154 external when it is declared in-class, even if an
13155 initializer is present. We mimic the non-template
13156 processing here. */
13164 }
13165 else
13166 {
13171 }
13179 /* Preserve a typedef that names a type. */
13181 {
13185 /* An alias template specialization can be dependent
13186 even if its underlying type is not. */
13188 }
13191 }
13196 }
13197 #undef RETURN
13199 out:
13200 /* Restore the file and line information. */
13204 }
13206 /* Substitute into the ARG_TYPES of a function type.
13207 If END is a TREE_CHAIN, leave it and any following types
13208 un-substituted. */
13210 static tree
13212 tree args,
13213 tree end,
13214 tsubst_flags_t complain,
13215 tree in_decl)
13216 {
13217 tree remaining_arg_types;
13221 tree default_arg;
13232 {
13233 /* For a pack expansion, perform substitution on the
13234 entire expression. Later on, we'll handle the arguments
13235 one-by-one. */
13240 /* So that we'll spin through the parameters, one by one. */
13242 else
13243 {
13244 /* We only partially substituted into the parameter
13245 pack. Our type is TYPE_PACK_EXPANSION. */
13248 }
13249 }
13262 {
13264 {
13268 }
13270 }
13271 /* DR 657. */
13275 /* Do array-to-pointer, function-to-pointer conversion, and ignore
13276 top-level qualifiers as required. */
13279 /* We do not substitute into default arguments here. The standard
13280 mandates that they be instantiated only when needed, which is
13281 done in build_over_call. */
13284 /* Except that we do substitute default arguments under tsubst_lambda_expr,
13285 since the new op() won't have any associated template arguments for us
13286 to refer to later. */
13292 {
13293 /* We've instantiated a template before its default arguments
13294 have been parsed. This can happen for a nested template
13295 class, and is not an error unless we require the default
13296 argument in a call of this function. */
13297 remaining_arg_types =
13300 }
13301 else
13302 remaining_arg_types =
13304 }
13307 }
13309 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
13310 *not* handle the exception-specification for FNTYPE, because the
13311 initial substitution of explicitly provided template parameters
13312 during argument deduction forbids substitution into the
13313 exception-specification:
13315 [temp.deduct]
13317 All references in the function type of the function template to the
13318 corresponding template parameters are replaced by the specified tem-
13319 plate argument values. If a substitution in a template parameter or
13320 in the function type of the function template results in an invalid
13321 type, type deduction fails. [Note: The equivalent substitution in
13322 exception specifications is done only when the function is instanti-
13323 ated, at which point a program is ill-formed if the substitution
13324 results in an invalid type.] */
13326 static tree
13328 tree args,
13329 tsubst_flags_t complain,
13330 tree in_decl)
13331 {
13332 tree return_type;
13334 tree fntype;
13336 /* The TYPE_CONTEXT is not used for function/method types. */
13339 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
13340 failure. */
13344 {
13345 /* Substitute the argument types. */
13357 {
13358 /* DR 1207: 'this' is in scope in the trailing return type. */
13360 }
13362 /* Substitute the return type. */
13366 {
13369 }
13370 }
13371 else
13372 /* Substitute the return type. */
13377 /* DR 486 clarifies that creation of a function type with an
13378 invalid return type is a deduction failure. */
13381 {
13383 {
13386 else
13388 }
13390 }
13391 /* And DR 657. */
13396 {
13397 /* Substitute the argument types. */
13402 }
13404 /* Construct a new type node and return it. */
13406 {
13411 }
13412 else
13413 {
13415 /* Don't pick up extra function qualifiers from the basetype. */
13418 {
13419 /* [temp.deduct]
13421 Type deduction may fail for any of the following
13422 reasons:
13424 -- Attempting to create "pointer to member of T" when T
13425 is not a class type. */
13428 r);
13430 }
13435 }
13442 }
13444 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
13445 ARGS into that specification, and return the substituted
13446 specification. If there is no specification, return NULL_TREE. */
13448 static tree
13450 tree args,
13451 tsubst_flags_t complain,
13452 tree in_decl,
13454 {
13455 tree specs;
13456 tree new_specs;
13461 {
13462 /* A noexcept-specifier. */
13467 {
13468 /* Defer instantiation of noexcept-specifiers to avoid
13469 excessive instantiations (c++/49107). */
13472 {
13473 /* We already partially instantiated this member template,
13474 so combine the new args with the old. */
13479 }
13480 else
13481 {
13484 }
13485 }
13486 else
13487 new_specs = tsubst_copy_and_build
13491 }
13493 {
13496 else
13498 {
13499 tree spec;
13504 {
13505 /* Expand the pack expansion type. */
13508 in_decl);
13514 else
13515 {
13516 /* We're substituting into a member template, so
13517 we got a TYPE_PACK_EXPANSION back. Add that
13518 expansion and move on. */
13522 expanded_specs,
13523 complain);
13526 }
13527 }
13530 {
13533 else
13538 complain);
13539 }
13542 }
13543 }
13545 }
13547 /* Take the tree structure T and replace template parameters used
13548 therein with the argument vector ARGS. IN_DECL is an associated
13549 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
13550 Issue error and warning messages under control of COMPLAIN. Note
13551 that we must be relatively non-tolerant of extensions here, in
13552 order to preserve conformance; if we allow substitutions that
13553 should not be allowed, we may allow argument deductions that should
13554 not succeed, and therefore report ambiguous overload situations
13555 where there are none. In theory, we could allow the substitution,
13556 but indicate that it should have failed, and allow our caller to
13557 make sure that the right thing happens, but we don't try to do this
13558 yet.
13560 This function is used for dealing with types, decls and the like;
13561 for expressions, use tsubst_expr or tsubst_copy. */
13563 tree
13565 {
13588 else
13593 /* Reuse typedefs. We need to do this to handle dependent attributes,
13594 such as attribute aligned. */
13597 {
13601 {
13602 /* DECL represents an alias template and we want to
13603 instantiate it. */
13607 }
13611 {
13615 }
13620 else
13621 /* The typedef is from a non-template context. */
13625 {
13627 r = cp_build_qualified_type_real
13631 }
13632 else
13633 {
13634 /* We don't have an instantiation yet, so drop the typedef. */
13639 }
13640 }
13657 {
13683 {
13689 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
13690 needed. */
13696 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
13697 with TREE_SIDE_EFFECTS that indicates this is not an integral
13698 constant expression. */
13701 {
13704 }
13707 }
13713 {
13719 /* Early in template argument deduction substitution, we don't
13720 want to reduce the level of 'auto', or it will be confused
13721 with a normal template parm in subsequent deduction. */
13733 {
13737 {
13738 /* See through ARGUMENT_PACK_SELECT arguments. */
13740 /* If the selected argument is an expansion E, that most
13741 likely means we were called from
13742 gen_elem_of_pack_expansion_instantiation during the
13743 substituting of pack an argument pack (which Ith
13744 element is a pack expansion, where I is
13745 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
13746 In this case, the Ith element resulting from this
13747 substituting is going to be a pack expansion, which
13748 pattern is the pattern of E. Let's return the
13749 pattern of E, and
13750 gen_elem_of_pack_expansion_instantiation will
13751 build the resulting pack expansion from it. */
13753 {
13754 /* Make sure we aren't throwing away arg info. */
13757 }
13758 }
13759 }
13764 {
13766 /* If ARG is an argument pack, we don't actually want to
13767 perform a substitution here, because substitutions
13768 for argument packs are only done
13769 element-by-element. We can get to this point when
13770 substituting the type of a non-type template
13771 parameter pack, when that type actually contains
13772 template parameter packs from an outer template, e.g.,
13774 template<typename... Types> struct A {
13775 template<Types... Values> struct B { };
13776 }; */
13780 {
13786 return cp_build_qualified_type_real
13788 }
13790 {
13791 /* We are processing a type constructed from a
13792 template template parameter. */
13803 /* Consider this code:
13805 template <template <class> class Template>
13806 struct Internal {
13807 template <class Arg> using Bind = Template<Arg>;
13808 };
13810 template <template <class> class Template, class Arg>
13811 using Instantiate = Template<Arg>; //#0
13813 template <template <class> class Template,
13814 class Argument>
13815 using Bind =
13816 Instantiate<Internal<Template>::template Bind,
13817 Argument>; //#1
13819 When #1 is parsed, the
13820 BOUND_TEMPLATE_TEMPLATE_PARM representing the
13821 parameter `Template' in #0 matches the
13822 UNBOUND_CLASS_TEMPLATE representing the argument
13823 `Internal<Template>::template Bind'; We then want
13824 to assemble the type `Bind<Argument>' that can't
13825 be fully created right now, because
13826 `Internal<Template>' not being complete, the Bind
13827 template cannot be looked up in that context. So
13828 we need to "store" `Bind<Argument>' for later
13829 when the context of Bind becomes complete. Let's
13830 store that in a TYPENAME_TYPE. */
13834 argvec),
13835 typename_type,
13836 complain);
13838 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
13839 are resolving nested-types in the signature of a
13840 member function templates. Otherwise ARG is a
13841 TEMPLATE_DECL and is the real template to be
13842 instantiated. */
13850 complain);
13851 return cp_build_qualified_type_real
13853 }
13856 else
13857 /* TEMPLATE_PARM_INDEX. */
13859 }
13862 /* This can happen during the attempted tsubst'ing in
13863 unify. This means that we don't yet have any information
13864 about the template parameter in question. */
13867 /* If we get here, we must have been looking at a parm for a
13868 more deeply nested template. Make a new version of this
13869 template parameter, but with a lower level. */
13871 {
13876 {
13878 r = cp_build_qualified_type_real
13882 }
13889 /* Break infinite recursion when substituting the constraints
13891 else
13892 {
13903 {
13904 /* Propagate constraints on placeholders. */
13909 {
13913 }
13914 }
13917 /* We have reduced the level of the template
13918 template parameter, but not the levels of its
13919 template parameters, so canonical_type_parameter
13920 will not be able to find the canonical template
13921 template parameter for this level. Thus, we
13922 require structural equality checking to compare
13923 TEMPLATE_TEMPLATE_PARMs. */
13927 else
13931 {
13933 /* We might need to substitute into the types of non-type
13934 template parameters. */
13946 }
13947 }
13951 /* OK, now substitute the type of the non-type parameter. We
13952 couldn't do it earlier because it might be an auto parameter,
13953 and we wouldn't need to if we had an argument. */
13962 }
13965 }
13968 {
13976 {
13980 }
13983 {
13987 }
13990 {
13994 }
14000 }
14003 /* We should never be tsubsting a binfo. */
14007 /* A vector of template arguments. */
14013 {
14017 /* [temp.deduct]
14019 Type deduction may fail for any of the following
14020 reasons:
14022 -- Attempting to create a pointer to reference type.
14023 -- Attempting to create a reference to a reference type or
14024 a reference to void.
14026 Core issue 106 says that creating a reference to a reference
14027 during instantiation is no longer a cause for failure. We
14028 only enforce this check in strict C++98 mode. */
14032 {
14035 /* We keep track of the last time we issued this error
14036 message to avoid spewing a ton of messages during a
14037 single bad template instantiation. */
14040 {
14045 else
14048 }
14051 }
14055 {
14057 {
14060 type);
14061 else
14063 type);
14064 }
14066 }
14068 {
14072 }
14074 /* In C++0x, during template argument substitution, when there is an
14075 attempt to create a reference to a reference type, reference
14076 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
14078 "If a template-argument for a template-parameter T names a type
14079 that is a reference to a type A, an attempt to create the type
14080 'lvalue reference to cv T' creates the type 'lvalue reference to
14081 A,' while an attempt to create the type type rvalue reference to
14082 cv T' creates the type T"
14083 */
14084 r = cp_build_reference_type
14087 else
14092 /* Will this ever be needed for TYPE_..._TO values? */
14096 }
14098 {
14101 {
14102 /* [temp.deduct]
14104 Type deduction may fail for any of the following
14105 reasons:
14107 -- Attempting to create "pointer to member of T" when T
14108 is not a class type. */
14112 }
14114 {
14118 }
14120 {
14124 }
14127 {
14128 /* The type of the implicit object parameter gets its
14129 cv-qualifiers from the FUNCTION_TYPE. */
14130 tree memptr;
14131 tree method_type
14136 complain);
14137 }
14138 else
14141 complain);
14142 }
14145 {
14146 tree fntype;
14147 tree specs;
14152 /* Substitute the exception specification. */
14160 }
14162 {
14167 /* As an optimization, we avoid regenerating the array type if
14168 it will obviously be the same as T. */
14172 /* These checks should match the ones in create_array_type_for_decl.
14174 [temp.deduct]
14176 The deduction may fail for any of the following reasons:
14178 -- Attempting to create an array with an element type that
14179 is void, a function type, or a reference type, or [DR337]
14180 an abstract class type. */
14186 {
14190 }
14198 {
14201 }
14204 }
14207 {
14219 {
14223 }
14225 {
14226 /* Normally, make_typename_type does not require that the CTX
14227 have complete type in order to allow things like:
14229 template <class T> struct S { typename S<T>::X Y; };
14231 But, such constructs have already been resolved by this
14232 point, so here CTX really should have complete type, unless
14233 it's a partial instantiation. */
14236 {
14240 }
14241 }
14248 {
14251 }
14254 {
14256 {
14260 else
14262 }
14264 {
14268 else
14270 }
14271 }
14273 return cp_build_qualified_type_real
14275 }
14278 {
14290 }
14293 {
14294 tree type;
14310 complain);
14311 }
14314 {
14315 tree type;
14326 {
14328 {
14332 }
14335 }
14346 else
14347 {
14351 /* In a template ~id could be either a complement expression
14352 or an unqualified-id naming a destructor; if instantiating
14353 it produces an expression, it's not an id-expression or
14354 member access. */
14357 }
14362 }
14365 {
14369 }
14373 {
14374 tree r;
14378 else
14386 }
14401 /* We should use one of the expression tsubsts for these codes. */
14407 }
14408 }
14410 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
14411 expression on the left-hand side of the "." or "->" operator. A
14412 baselink indicates a function from a base class. Both the
14413 BASELINK_ACCESS_BINFO and the base class referenced may indicate
14414 bases of the template class, rather than the instantiated class.
14415 In addition, lookups that were not ambiguous before may be
14416 ambiguous now. Therefore, we perform the lookup again. */
14418 static tree
14421 {
14434 {
14441 }
14449 {
14454 }
14456 /* If lookup found a single function, mark it as used at this point.
14457 (If it lookup found multiple functions the one selected later by
14458 overload resolution will be marked as used at that point.) */
14466 {
14467 /* Add back the template arguments, if present. */
14473 /* Update the conversion operator type. */
14475 }
14481 {
14483 qualifying_scope,
14484 object_type);
14486 /* We need to call adjust_result_of_qualified_name_lookup in case the
14487 destructor names a base class, but we unset BASELINK_QUALIFIED_P
14488 so that we still get virtual function binding. */
14490 }
14493 }
14495 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
14496 true if the qualified-id will be a postfix-expression in-and-of
14497 itself; false if more of the postfix-expression follows the
14498 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
14499 of "&". */
14501 static tree
14505 {
14506 tree expr;
14507 tree scope;
14508 tree name;
14510 tree template_args;
14515 /* Figure out what name to look up. */
14518 {
14528 }
14529 else
14530 {
14533 }
14535 /* Substitute into the qualifying scope. When there are no ARGS, we
14536 are just trying to simplify a non-dependent expression. In that
14537 case the qualifying scope may be dependent, and, in any case,
14538 substituting will not help. */
14541 {
14544 }
14545 else
14549 {
14556 }
14559 {
14561 {
14562 /* A BIT_NOT_EXPR is used to represent a destructor. */
14564 {
14568 }
14569 else
14572 }
14573 else
14577 {
14579 {
14583 }
14585 }
14586 }
14589 {
14591 scope);
14592 /* Remember that there was a reference to this entity. */
14595 }
14598 {
14604 }
14607 {
14610 complain);
14611 else
14613 }
14619 {
14620 expr = (adjust_result_of_qualified_name_lookup
14622 expr = (finish_qualified_id_expr
14626 }
14628 /* Expressions do not generally have reference type. */
14630 /* However, if we're about to form a pointer-to-member, we just
14631 want the referenced member referenced. */
14639 }
14641 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
14642 initializer, DECL is the substituted VAR_DECL. Other arguments are as
14643 for tsubst. */
14645 static tree
14648 {
14655 {
14656 /* If we had an initializer but it
14657 instantiated to nothing,
14658 value-initialize the object. This will
14659 only occur when the initializer was a
14660 pack expansion where the parameter packs
14661 used in that expansion were of length
14662 zero. */
14664 complain);
14669 }
14672 }
14674 /* Like tsubst, but deals with expressions. This function just replaces
14675 template parms; to finish processing the resultant expression, use
14676 tsubst_copy_and_build or tsubst_expr. */
14678 static tree
14680 {
14682 tree r;
14690 {
14695 {
14696 /* We get here for a use of 'this' in an NSDMI. */
14700 /* This can happen for a parameter name used later in a function
14701 declaration (such as in a late-specified return type). Just
14702 make a dummy decl, since it's only used for its type. */
14705 /* Give it the template pattern as its context; its true context
14706 hasn't been instantiated yet and this is good enough for
14707 mangling. */
14709 }
14718 {
14719 tree enum_type;
14720 tree v;
14724 /* There is no need to substitute into namespace-scope
14725 enumerators. */
14728 /* If ARGS is NULL, then T is known to be non-dependent. */
14732 /* Unfortunately, we cannot just call lookup_name here.
14733 Consider:
14735 template <int I> int f() {
14736 enum E { a = I };
14737 struct S { void g() { E e = a; } };
14738 };
14740 When we instantiate f<7>::S::g(), say, lookup_name is not
14741 clever enough to find f<7>::a. */
14742 enum_type
14752 /* We didn't find the name. That should never happen; if
14753 name-lookup found it during preliminary parsing, we
14754 should find it again here during instantiation. */
14756 }
14761 {
14762 /* Check for a local specialization set up by
14763 tsubst_pack_expansion. */
14765 {
14769 }
14771 /* When retrieving a capture pack from a generic lambda, remove the
14772 lambda call op's own template argument list from ARGS. Only the
14773 template arguments active for the closure type should be used to
14774 retrieve the pack specialization. */
14780 /* Otherwise return the full NONTYPE_ARGUMENT_PACK that
14781 tsubst_decl put in the hash table. */
14783 }
14786 {
14787 tree ctx;
14792 {
14795 {
14799 }
14801 }
14802 }
14812 {
14815 {
14816 /* First try name lookup to find the instantiation. */
14819 {
14820 /* Make sure that the one we found is the one we want. */
14824 }
14828 else
14829 {
14830 /* This can happen for a variable used in a
14831 late-specified return type of a local lambda, or for a
14832 local static or constant. Building a new VAR_DECL
14833 should be OK in all those cases. */
14836 /* Avoid infinite recursion (79640). */
14839 {
14840 /* We can't call cp_finish_decl, so handle the
14841 initializer by hand. */
14856 }
14863 }
14864 /* Remember this for subsequent uses. */
14867 }
14868 }
14869 else
14879 /* An OVERLOAD will always be a non-dependent overload set; an
14880 overload set from function scope will just be represented with an
14881 IDENTIFIER_NODE, and from class scope with a BASELINK. */
14883 /* We must have marked any lookups as persistent. */
14899 {
14900 /* Template template argument like the following example need
14901 special treatment:
14903 template <template <class> class TT> struct C {};
14904 template <class T> struct D {
14905 template <class U> struct E {};
14906 C<E> c; // #1
14907 };
14908 D<int> d; // #2
14910 We are processing the template argument `E' in #1 for
14911 the template instantiation #2. Originally, `E' is a
14912 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
14913 have to substitute this with one having context `D<int>'. */
14917 {
14918 /* When rewriting a constructor into a deduction guide, a
14919 non-dependent name can become dependent, so memtmpl<args>
14920 becomes context::template memtmpl<args>. */
14924 }
14926 }
14927 else
14928 /* Ordinary template template argument. */
14939 {
14943 }
14948 {
14957 /* We only want to compute the number of arguments. */
14960 else
14967 {
14969 /* Set TREE_USED for the benefit of -Wunused. */
14973 }
14981 {
14986 else
14992 else
14995 }
14996 else
14998 }
15000 {
15008 }
15009 /* Fall through */
15025 {
15029 }
15032 {
15033 tree object;
15034 tree name;
15039 {
15043 }
15046 {
15056 }
15061 in_decl);
15062 else
15065 }
15103 {
15107 }
15110 {
15115 }
15118 {
15122 }
15125 {
15133 }
15139 {
15146 }
15149 {
15156 }
15159 {
15166 }
15169 {
15170 /* Substituted template arguments */
15179 }
15182 {
15202 }
15227 /* Fall through. */
15230 {
15233 }
15234 else
15238 /* This is handled by tsubst_copy_and_build. */
15242 {
15246 }
15249 /* We shouldn't have built any of these during initial template
15250 generation. Instead, they should be built during instantiation
15251 in response to the saved STMT_IS_FULL_EXPR_P setting. */
15255 {
15265 }
15283 {
15284 /* Instantiate any typedefs in the type. */
15289 }
15292 /* These can sometimes show up in a partial instantiation, but never
15293 involve template parms. */
15309 /* We shouldn't get here, but keep going if !flag_checking. */
15313 }
15314 }
15316 /* Helper function for tsubst_omp_clauses, used for instantiation of
15317 OMP_CLAUSE_DECL of clauses. */
15319 static tree
15321 tree in_decl)
15322 {
15326 /* Handle an OpenMP array section represented as a TREE_LIST (or
15327 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15328 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15329 TREE_LIST. We can handle it exactly the same as an array section
15330 (purpose, value, and a chain), even though the nomenclature
15331 (low_bound, length, etc) is different. */
15333 {
15334 tree low_bound
15340 in_decl);
15349 }
15352 /* Undo convert_from_reference tsubst_expr could have called. */
15358 }
15360 /* Like tsubst_copy, but specifically for OpenMP clauses. */
15362 static tree
15365 {
15370 {
15376 {
15379 {
15385 }
15386 /* FALLTHRU */
15401 in_decl);
15433 {
15436 {
15443 }
15444 else
15446 }
15449 in_decl);
15455 in_decl);
15463 in_decl);
15465 {
15468 }
15473 else
15476 in_decl,
15500 }
15503 {
15513 /* tsubst_expr on SCOPE_REF results in returning
15514 finish_non_static_data_member result. Undo that here. */
15518 {
15523 {
15527 CASE_CONVERT:
15536 /* FALLTHRU */
15540 }
15541 }
15547 {
15550 {
15553 }
15554 }
15558 }
15559 }
15563 {
15568 {
15571 }
15572 }
15574 }
15576 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
15578 static tree
15580 tree in_decl)
15581 {
15582 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
15602 {
15605 else
15606 {
15610 }
15611 }
15616 #undef RECUR
15617 }
15619 /* Used to temporarily communicate the list of #pragma omp parallel
15620 clauses to #pragma omp for instantiation if they are combined
15621 together. */
15625 /* Substitute one OMP_FOR iterator. */
15627 static void
15632 {
15633 #define RECUR(NODE) \
15634 tsubst_expr ((NODE), args, complain, in_decl, \
15635 integral_constant_expression_p)
15642 {
15645 }
15651 {
15652 /* We need to jump through some hoops to handle declarations in the
15653 init-statement, since we might need to handle auto deduction,
15654 but we need to keep control of initialization. */
15658 }
15659 else
15660 {
15662 {
15665 {
15669 {
15673 CASE_CONVERT:
15681 {
15684 }
15685 /* FALLTHRU */
15689 }
15690 }
15691 }
15692 else
15694 }
15705 {
15707 {
15708 /* Declare the variable, but don't let that initialize it. */
15713 }
15718 {
15723 }
15724 else
15731 }
15734 {
15735 /* Declare and initialize the variable. */
15738 }
15740 {
15744 {
15746 {
15752 {
15755 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
15760 }
15763 {
15765 decl);
15767 }
15770 {
15772 decl);
15774 }
15775 else
15777 }
15780 }
15782 {
15787 {
15790 }
15791 }
15792 }
15795 {
15799 }
15800 else
15804 {
15815 {
15823 }
15824 else
15830 {
15836 }
15840 {
15848 }
15849 else
15855 }
15861 #undef RECUR
15862 }
15864 /* Helper function of tsubst_expr, find OMP_TEAMS inside
15865 of OMP_TARGET's body. */
15867 static tree
15869 {
15872 {
15881 }
15883 }
15885 /* Helper function for tsubst_expr. For decomposition declaration
15886 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
15887 also the corresponding decls representing the identifiers
15888 of the decomposition declaration. Return DECL if successful
15889 or error_mark_node otherwise, set *FIRST to the first decl
15890 in the list chained through DECL_CHAIN and *CNT to the number
15891 of such decls. */
15893 static tree
15897 {
15902 decl2
15907 {
15909 {
15912 }
15929 {
15932 }
15933 else
15935 }
15938 }
15940 /* Like tsubst_copy for expressions, etc. but also does semantic
15941 processing. */
15943 tree
15946 {
15947 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
15948 #define RECUR(NODE) \
15949 tsubst_expr ((NODE), args, complain, in_decl, \
15950 integral_constant_expression_p)
15953 tree r;
15954 location_t loc;
15966 {
15968 {
15969 tree_stmt_iterator i;
15973 }
15988 else
15998 {
16000 tree init;
16006 {
16016 else
16018 }
16020 {
16021 /* Don't build up decls for a variadic capture proxy, we'll
16022 instantiate the elements directly as needed. */
16024 }
16027 {
16028 /* We're in tsubst_lambda_expr, we've already inserted a new
16029 capture proxy, so look it up and register it. */
16035 }
16038 /* Don't copy the old closure; we'll create a new one in
16039 tsubst_lambda_expr. */
16041 else
16042 {
16046 {
16047 /* By marking the declaration as instantiated, we avoid
16048 trying to instantiate it. Since instantiate_decl can't
16049 handle local variables, and since we've already done
16050 all that needs to be done, that's the right thing to
16051 do. */
16056 /* Anonymous aggregates are a special case. */
16059 {
16062 {
16066 }
16068 }
16074 {
16079 }
16080 else
16081 {
16086 {
16087 /* For __PRETTY_FUNCTION__ we have to adjust the
16088 initializer. */
16092 }
16093 else
16097 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
16103 {
16105 tree first;
16111 }
16112 }
16113 }
16114 }
16117 }
16127 {
16131 }
16136 {
16144 {
16146 tree first;
16151 }
16152 else
16159 }
16166 {
16170 }
16176 {
16180 }
16193 else
16194 {
16201 }
16207 {
16216 }
16224 else
16232 else
16253 {
16260 }
16264 {
16266 tree label;
16273 }
16279 /* Computed goto's must be tsubst'd into. On the other hand,
16280 non-computed gotos must not be; the identifier in question
16281 will have no binding. */
16283 else
16289 {
16305 }
16310 {
16315 }
16316 else
16317 {
16322 else
16329 else
16335 else
16337 }
16341 {
16345 {
16347 /* Prevent instantiate_decl from trying to instantiate
16348 this variable. We've already done all that needs to be
16349 done. */
16352 }
16357 }
16363 {
16364 /* Local classes are not independent templates; they are
16365 instantiated along with their containing function. And this
16366 way we don't have to deal with pushing out of one local class
16367 to instantiate a member of another local class. */
16368 /* Closures are handled by the LAMBDA_EXPR. */
16378 }
16382 {
16383 tree condition;
16386 condition =
16388 args,
16397 }
16403 in_decl);
16438 {
16451 in_decl);
16453 {
16460 }
16472 integral_constant_expression_p);
16483 else
16484 {
16492 }
16496 }
16501 /* FALLTHRU */
16508 in_decl);
16525 in_decl);
16536 {
16539 {
16540 /* For combined target teams, ensure the num_teams and
16541 thread_limit clause expressions are evaluated on the host,
16542 before entering the target construct. */
16543 tree c;
16549 {
16558 OMP_CLAUSE_FIRSTPRIVATE);
16562 }
16563 }
16564 }
16624 {
16629 {
16632 }
16638 }
16639 else
16640 {
16647 {
16650 }
16653 {
16658 {
16661 }
16667 }
16668 else
16669 {
16673 }
16676 }
16680 {
16686 {
16690 {
16695 }
16699 }
16700 else
16701 {
16706 }
16707 }
16711 {
16715 }
16728 /* If the first operand was a statement, we're done with it. */
16732 complain));
16746 integral_constant_expression_p));
16747 }
16750 out:
16753 #undef RECUR
16754 #undef RETURN
16755 }
16757 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
16758 function. For description of the body see comment above
16759 cp_parser_omp_declare_reduction_exprs. */
16761 static void
16763 {
16769 tree_stmt_iterator tsi;
16780 {
16799 }
16801 {
16821 }
16822 }
16824 /* T is a postfix-expression that is not being used in a function
16825 call. Return the substituted version of T. */
16827 static tree
16829 tsubst_flags_t complain,
16830 tree in_decl)
16831 {
16835 else
16841 }
16843 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
16844 instantiation context. Instantiating a pack expansion containing a lambda
16845 might result in multiple lambdas all based on the same lambda in the
16846 template. */
16848 tree
16850 {
16864 else
16872 {
16884 else
16889 {
16898 }
16899 else
16900 {
16906 }
16907 }
16911 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
16929 else
16930 {
16931 /* Fix the type of 'this'. */
16937 {
16941 }
16942 else
16943 {
16947 }
16949 /* Let finish_function set this. */
16970 /* The capture list was built up in reverse order; fix that now. */
16977 }
16984 }
16986 /* Like tsubst but deals with expressions and performs semantic
16987 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
16989 tree
16991 tree args,
16992 tsubst_flags_t complain,
16993 tree in_decl,
16996 {
16997 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
16998 #define RECUR(NODE) \
16999 tsubst_copy_and_build (NODE, args, complain, in_decl, \
17001 integral_constant_expression_p)
17004 location_t loc;
17013 /* N3276 decltype magic only applies to calls at the top level or on the
17014 right side of a comma. */
17019 {
17022 /* Fall through. */
17024 {
17025 tree decl;
17026 cp_id_kind idk;
17031 {
17034 }
17036 /* Look up the name. */
17039 /* By convention, expressions use ERROR_MARK_NODE to indicate
17040 failure, not NULL_TREE. */
17046 integral_constant_expression_p,
17054 input_location);
17058 {
17062 }
17064 }
17067 {
17068 tree object;
17078 {
17083 }
17089 {
17092 }
17093 else
17100 else
17102 }
17105 {
17109 {
17110 /* A type conversion to reference type will be enclosed in
17111 such an indirect ref, but the substitution of the cast
17112 will have also added such an indirect ref. */
17114 }
17115 else
17123 }
17126 {
17130 }
17133 {
17137 {
17142 }
17144 /* We'll pass this to convert_nontype_argument again, we don't need
17145 to actually perform any conversion here. */
17151 flags));
17152 }
17155 {
17159 }
17166 {
17167 tree type;
17173 {
17178 }
17185 {
17203 }
17206 }
17240 else
17242 in_decl);
17277 {
17284 tree r = build_x_binary_op
17286 op0,
17288 ? ERROR_MARK
17290 op1,
17292 ? ERROR_MARK
17300 }
17303 {
17307 }
17323 /* Fall through */
17326 {
17327 tree r;
17333 {
17334 /* When there are no ARGS, we are trying to evaluate a
17335 non-dependent expression from the parser. Trying to do
17336 the substitutions may not work. */
17339 }
17340 else
17341 {
17346 else
17349 /*integral_constant_expression_p=*/
17353 }
17357 else
17361 {
17363 {
17365 {
17369 }
17370 else
17374 }
17376 }
17378 }
17381 {
17391 }
17407 {
17411 tree r = build_x_modify_expr
17414 /* TREE_NO_WARNING must be set if either the expression was
17415 parenthesized or it uses an operator such as >>= rather
17416 than plain assignment. In the former case, it was already
17417 set and must be copied. In the latter case,
17418 build_x_modify_expr sets it and it must not be reset
17419 here. */
17424 }
17429 /* Remember that there was a reference to this entity. */
17436 {
17441 tree ret;
17445 else
17446 {
17450 }
17452 /* If there was an initializer in the original tree, but it
17453 instantiated to an empty list, then we should pass a
17454 non-NULL empty vector to tell build_new that it was an
17455 empty initializer() rather than no initializer. This can
17456 only happen when the initializer is a pack expansion whose
17457 parameter packs are of length zero. */
17460 else
17461 {
17465 else
17466 {
17469 }
17470 }
17476 complain);
17484 }
17487 {
17493 complain));
17494 }
17497 {
17501 integral_constant_expression_p);
17503 op0,
17506 }
17509 {
17510 tree function;
17515 tree ret;
17518 /* Internal function with no arguments. */
17522 /* When we parsed the expression, we determined whether or
17523 not Koenig lookup should be performed. */
17526 {
17529 }
17531 {
17536 }
17538 {
17539 /* Do nothing; calling tsubst_copy_and_build on an identifier
17540 would incorrectly perform unqualified lookup again.
17542 Note that we can also have an IDENTIFIER_NODE if the earlier
17543 unqualified lookup found a member function; in that case
17544 koenig_p will be false and we do want to do the lookup
17545 again to find the instantiated member function.
17547 FIXME but doing that causes c++/15272, so we need to stop
17548 using IDENTIFIER_NODE in that situation. */
17550 }
17551 else
17552 {
17554 {
17560 }
17561 else
17566 /* Avoid error about taking the address of a constructor. */
17570 in_decl,
17572 integral_constant_expression_p);
17576 }
17581 {
17586 else
17587 {
17588 /* Expand the pack expansion and push each entry onto
17589 CALL_ARGS. */
17592 {
17597 {
17602 }
17603 }
17604 else
17605 {
17606 /* A partial substitution. Add one entry. */
17608 }
17609 }
17610 }
17612 /* We do not perform argument-dependent lookup if normal
17613 lookup finds a non-function, in accordance with the
17614 expected resolution of DR 218. */
17617 /* If lookup found a member function, the Koenig lookup is
17618 not appropriate, even if an unqualified-name was used
17619 to denote the function. */
17622 /* Only do this when substitution turns a dependent call
17623 into a non-dependent call. */
17631 {
17633 {
17634 /* For backwards compatibility and good diagnostics, try
17635 the unqualified lookup again if we aren't in SFINAE
17636 context. */
17637 tree unq = (tsubst_copy_and_build
17639 integral_constant_expression_p));
17641 {
17644 }
17647 {
17648 /* In a lambda fn, we have to be careful to not
17649 introduce new this captures. Legacy code can't
17650 be using lambdas anyway, so it's ok to be
17651 stricter. */
17656 "and no declarations were found by "
17657 "argument-dependent lookup at the point "
17664 else
17668 {
17679 {
17681 input_location);
17683 "declarations in dependent base %qT are "
17689 else
17693 }
17694 else
17696 "%qD declared here, later in the "
17699 {
17702 }
17703 }
17706 }
17707 }
17709 {
17714 }
17715 }
17717 /* Remember that there was a reference to this entity. */
17721 {
17724 }
17726 /* Put back tf_decltype for the actual call. */
17731 {
17735 {
17737 "wrong number of arguments to "
17740 }
17741 else
17743 input_location),
17748 /* Unsupported internal function with arguments. */
17750 }
17753 complain);
17755 {
17770 complain);
17771 else
17772 ret = (build_new_method_call
17777 complain));
17778 }
17779 else
17782 koenig_p,
17783 complain);
17788 {
17794 {
17800 {
17802 /* The thunk location is not interesting. */
17804 }
17805 }
17806 }
17809 }
17812 {
17818 {
17820 {
17825 }
17826 else
17827 {
17832 }
17834 }
17835 else
17836 {
17839 }
17843 }
17846 {
17851 input_location));
17852 }
17855 {
17863 {
17864 /* We have pack expansions, so expand those and
17865 create a new list out of it. */
17868 tree chain;
17871 /* Expand the argument expressions. */
17879 /* Build the rest of the list. */
17884 /* Determine the number of arguments. */
17886 {
17889 }
17892 else
17893 {
17894 /* Since we only performed a partial substitution into
17895 the argument pack, we only RETURN (a single list
17896 node. */
17903 }
17905 /* Convert the argument vectors into a TREE_LIST */
17908 {
17909 /* Grab the Ith values. */
17910 i--;
17913 value
17917 /* Build the list (backwards). */
17919 }
17922 }
17938 }
17941 {
17942 tree object;
17943 tree object_type;
17944 tree member;
17945 tree r;
17949 /* Remember that there was a reference to this entity. */
17960 else
17966 {
17971 }
17975 {
17977 {
17982 {
17985 }
17987 {
17992 }
17993 }
17994 }
17997 {
17998 /* Lookup the template functions now that we know what the
17999 scope is. */
18007 {
18010 args);
18011 member = (adjust_result_of_qualified_name_lookup
18013 object_type));
18014 }
18015 else
18016 {
18018 input_location);
18020 }
18021 }
18025 {
18027 {
18031 else
18034 }
18036 }
18040 complain);
18044 }
18051 {
18059 tree r;
18064 /* digest_init will do the wrong thing if we let it. */
18068 /* We do not want to process the index of aggregate
18069 initializers as they are identifier nodes which will be
18070 looked up by digest_init. */
18076 {
18078 /* An identifier index is looked up in the type
18079 being initialized, not the current scope. */
18084 {
18085 /* Substitute into the pack expansion. */
18087 in_decl);
18091 ;
18093 /* Just move the argument into place. */
18095 else
18096 {
18097 /* Update the length of the final CONSTRUCTOR
18098 arguments vector, and note that we will need to
18099 copy.*/
18102 }
18103 }
18104 else
18106 }
18109 {
18114 {
18116 {
18121 }
18122 else
18124 }
18125 }
18131 {
18136 }
18140 }
18143 {
18146 {
18149 }
18150 else
18151 {
18154 }
18155 }
18161 {
18162 /* We don't build decls for an instantiation of a
18163 variadic capture proxy, we instantiate the elements
18164 when needed. */
18167 }
18168 /* Fall through */
18171 {
18173 /* ??? We're doing a subset of finish_id_expression here. */
18175 && !processing_template_decl
18176 && !cp_unevaluated_operand
18179 {
18181 /* Replace an evaluated use of the thread_local variable with
18182 a call to its wrapper. */
18184 }
18189 /* If the original type was a reference, we'll be wrapped in
18190 the appropriate INDIRECT_REF. */
18193 }
18196 {
18200 }
18203 {
18204 tree object_ptr
18211 }
18218 {
18229 }
18232 {
18238 integral_constant_expression_p);
18242 /* If the resulting list of expression statement is empty,
18243 fold it further into void_node. */
18248 }
18251 {
18255 }
18258 /* We can get here for a constant initializer of non-dependent type.
18259 FIXME stop folding in cp_parser_initializer_clause. */
18260 {
18262 complain);
18264 }
18268 integral_constant_expression_p));
18274 {
18279 complain));
18280 }
18286 /* Handle Objective-C++ constructs, if appropriate. */
18287 {
18288 tree subst
18293 }
18295 }
18297 #undef RECUR
18298 #undef RETURN
18299 out:
18302 }
18304 /* Verify that the instantiated ARGS are valid. For type arguments,
18305 make sure that the type's linkage is ok. For non-type arguments,
18306 make sure they are constants if they are integral or enumerations.
18307 Emit an error under control of COMPLAIN, and return TRUE on error. */
18309 static bool
18311 {
18315 {
18325 }
18327 {
18328 /* [basic.link]: A name with no linkage (notably, the name
18329 of a class or enumeration declared in a local scope)
18330 shall not be used to declare an entity with linkage.
18331 This implies that names with no linkage cannot be used as
18332 template arguments
18334 DR 757 relaxes this restriction for C++0x. */
18339 {
18340 /* DR 488 makes use of a type with no linkage cause
18341 type deduction to fail. */
18343 {
18346 else
18349 }
18351 }
18352 /* In order to avoid all sorts of complications, we do not
18353 allow variably-modified types as template arguments. */
18355 {
18359 }
18360 }
18361 /* Class template and alias template arguments should be OK. */
18363 ;
18364 /* A non-type argument of integral or enumerated type must be a
18365 constant. */
18370 {
18374 }
18376 }
18378 static bool
18380 {
18385 {
18388 }
18392 }
18394 /* We're out of SFINAE context now, so generate diagnostics for the access
18395 errors we saw earlier when instantiating D from TMPL and ARGS. */
18397 static void
18399 {
18411 }
18413 /* Instantiate the indicated variable, function, or alias template TMPL with
18414 the template arguments in TARG_PTR. */
18416 static tree
18418 {
18420 tree fndecl;
18421 tree gen_tmpl;
18422 tree spec;
18430 /* If this function is a clone, handle it specially. */
18432 {
18433 tree spec;
18434 tree clone;
18436 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
18437 DECL_CLONED_FUNCTION. */
18443 /* Look for the clone. */
18447 /* We should always have found the clone by now. */
18450 }
18455 /* Check to see if we already have this specialization. */
18459 /* targ_ptr only has the innermost template args, so add the outer ones
18460 from tmpl, which could be either a partial instantiation or gen_tmpl (in
18461 the case of a non-dependent call within a template definition). */
18462 targ_ptr = (add_outermost_template_args
18464 targ_ptr));
18466 /* It would be nice to avoid hashing here and then again in tsubst_decl,
18467 but it doesn't seem to be on the hot path. */
18476 {
18478 {
18482 }
18484 }
18487 complain))
18490 /* We are building a FUNCTION_DECL, during which the access of its
18491 parameters and return types have to be checked. However this
18492 FUNCTION_DECL which is the desired context for access checking
18493 is not built yet. We solve this chicken-and-egg problem by
18494 deferring all checks until we have the FUNCTION_DECL. */
18497 /* Instantiation of the function happens in the context of the function
18498 template, not the context of the overload resolution we're doing. */
18500 /* If there are dependent arguments, e.g. because we're doing partial
18501 ordering, make sure processing_template_decl stays set. */
18505 {
18509 }
18515 {
18516 /* We need to determine if we're using a partial or explicit
18517 specialization now, because the type of the variable could be
18518 different. */
18524 {
18529 }
18530 }
18532 /* Substitute template parameters to obtain the specialization. */
18540 {
18543 }
18545 /* The DECL_TI_TEMPLATE should always be the immediate parent
18546 template, not the most general template. */
18550 /* Now we know the specialization, compute access previously
18551 deferred. Do no access control for inheriting constructors,
18552 as we already checked access for the inherited constructor. */
18555 {
18560 }
18563 /* If we've just instantiated the main entry point for a function,
18564 instantiate all the alternate entry points as well. We do this
18565 by cloning the instantiation of the main entry point, not by
18566 instantiating the template clones. */
18571 {
18573 {
18574 /* Remember to reinstantiate when we're out of SFINAE so the user
18575 can see the errors. */
18577 }
18579 }
18581 }
18583 /* Wrapper for instantiate_template_1. */
18585 tree
18587 {
18588 tree ret;
18593 }
18595 /* Instantiate the alias template TMPL with ARGS. Also push a template
18596 instantiation level, which instantiate_template doesn't do because
18597 functions and variables have sufficient context established by the
18598 callers. */
18600 static tree
18602 {
18609 {
18612 }
18614 args =
18622 /* We can't free this if a pending_template entry or last_error_tinst_level
18623 is pointing at it. */
18629 }
18631 /* PARM is a template parameter pack for FN. Returns true iff
18632 PARM is used in a deducible way in the argument list of FN. */
18634 static bool
18636 {
18639 {
18641 tree packs;
18647 {
18648 /* The template parameter pack is used in a function parameter
18649 pack. If this is the end of the parameter list, the
18650 template parameter pack is deducible. */
18653 else
18654 /* Otherwise, not. Well, it could be deduced from
18655 a non-pack parameter, but doing so would end up with
18656 a deduction mismatch, so don't bother. */
18658 }
18659 }
18660 /* The template parameter pack isn't used in any function parameter
18661 packs, but it might be used deeper, e.g. tuple<Args...>. */
18663 }
18665 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
18666 NARGS elements of the arguments that are being used when calling
18667 it. TARGS is a vector into which the deduced template arguments
18668 are placed.
18670 Returns either a FUNCTION_DECL for the matching specialization of FN or
18671 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
18672 true, diagnostics will be printed to explain why it failed.
18674 If FN is a conversion operator, or we are trying to produce a specific
18675 specialization, RETURN_TYPE is the return type desired.
18677 The EXPLICIT_TARGS are explicit template arguments provided via a
18678 template-id.
18680 The parameter STRICT is one of:
18682 DEDUCE_CALL:
18683 We are deducing arguments for a function call, as in
18684 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
18685 deducing arguments for a call to the result of a conversion
18686 function template, as in [over.call.object].
18688 DEDUCE_CONV:
18689 We are deducing arguments for a conversion function, as in
18690 [temp.deduct.conv].
18692 DEDUCE_EXACT:
18693 We are deducing arguments when doing an explicit instantiation
18694 as in [temp.explicit], when determining an explicit specialization
18695 as in [temp.expl.spec], or when taking the address of a function
18696 template, as in [temp.deduct.funcaddr]. */
18698 tree
18700 tree explicit_targs,
18701 tree targs,
18704 tree return_type,
18705 unification_kind_t strict,
18709 {
18710 tree parms;
18711 tree fntype;
18724 tree tinst;
18730 full_targs = (add_outermost_template_args
18732 targs));
18737 /* In C++0x, it's possible to have a function template whose type depends
18738 on itself recursively. This is most obvious with decltype, but can also
18739 occur with enumeration scope (c++/48969). So we need to catch infinite
18740 recursion and reject the substitution at deduction time; this function
18741 will return error_mark_node for any repeated substitution.
18743 This also catches excessive recursion such as when f<N> depends on
18744 f<N-1> across all integers, and returns error_mark_node for all the
18745 substitutions back up to the initial one.
18747 This is, of course, not reentrant. */
18757 {
18758 /* [temp.deduct]
18760 The specified template arguments must match the template
18761 parameters in kind (i.e., type, nontype, template), and there
18762 must not be more arguments than there are parameters;
18763 otherwise type deduction fails.
18765 Nontype arguments must match the types of the corresponding
18766 nontype template parameters, or must be convertible to the
18767 types of the corresponding nontype parameters as specified in
18768 _temp.arg.nontype_, otherwise type deduction fails.
18770 All references in the function type of the function template
18771 to the corresponding template parameters are replaced by the
18772 specified template argument values. If a substitution in a
18773 template parameter or in the function type of the function
18774 template results in an invalid type, type deduction fails. */
18785 explicit_targs);
18787 /* Adjust any explicit template arguments before entering the
18788 substitution context. */
18789 explicit_targs
18791 complain,
18797 /* Substitute the explicit args into the function type. This is
18798 necessary so that, for instance, explicitly declared function
18799 arguments can match null pointed constants. If we were given
18800 an incomplete set of explicit args, we must not do semantic
18801 processing during substitution as we could create partial
18802 instantiations. */
18804 {
18809 /* Dig out the actual parm. */
18812 {
18815 }
18817 {
18820 }
18823 /* No explicit argument for this template parameter. */
18827 {
18828 /* Mark the argument pack as "incomplete". We could
18829 still deduce more arguments during unification.
18830 We remove this mark in type_unification_real. */
18832 {
18836 }
18838 /* We have some incomplete argument packs. */
18840 }
18841 }
18845 {
18848 }
18851 /* Ignore any access checks; we'll see them again in
18852 instantiate_template and they might have the wrong
18853 access path at this point. */
18865 /* Place the explicitly specified arguments in TARGS. */
18869 }
18871 /* Never do unification on the 'this' parameter. */
18875 {
18876 /* We're deducing for a call to the result of a template conversion
18877 function. The parms we really want are in return_type. */
18881 }
18883 {
18892 }
18894 /* We allow incomplete unification without an error message here
18895 because the standard doesn't seem to explicitly prohibit it. Our
18896 callers must be ready to deal with unification failures in any
18897 event. */
18900 /* If we aren't explaining yet, push tinst context so we can see where
18901 any errors (e.g. from class instantiations triggered by instantiation
18902 of default template arguments) come from. If we are explaining, this
18903 context is redundant. */
18905 {
18908 }
18910 /* type_unification_real will pass back any access checks from default
18911 template argument substitution. */
18923 /* Now that we have bindings for all of the template arguments,
18924 ensure that the arguments deduced for the template template
18925 parameters have compatible template parameter lists. We cannot
18926 check this property before we have deduced all template
18927 arguments, because the template parameter types of a template
18928 template parameter might depend on prior template parameters
18929 deduced after the template template parameter. The following
18930 ill-formed example illustrates this issue:
18932 template<typename T, template<T> class C> void f(C<5>, T);
18934 template<int N> struct X {};
18936 void g() {
18937 f(X<5>(), 5l); // error: template argument deduction fails
18938 }
18940 The template parameter list of 'C' depends on the template type
18941 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
18942 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
18943 time that we deduce 'C'. */
18946 {
18949 }
18951 /* All is well so far. Now, check:
18953 [temp.deduct]
18955 When all template arguments have been deduced, all uses of
18956 template parameters in nondeduced contexts are replaced with
18957 the corresponding deduced argument values. If the
18958 substitution results in an invalid type, as described above,
18959 type deduction fails. */
18962 {
18965 }
18967 /* Also collect access checks from the instantiation. */
18980 /* Now perform any access checks encountered during substitution. */
18987 /* If we're looking for an exact match, check that what we got
18988 is indeed an exact match. It might not be if some template
18989 parameters are used in non-deduced contexts. But don't check
18990 for an exact match if we have dependent template arguments;
18991 in that case we're doing partial ordering, and we already know
18992 that we have two candidates that will provide the actual type. */
18994 {
18998 tree sarg
19004 {
19008 }
19009 }
19011 /* After doing deduction with the inherited constructor, actually return an
19012 instantiation of the inheriting constructor. */
19018 fail:
19021 {
19023 /* Reset once we're all the way out. */
19025 }
19027 /* We can't free this if a pending_template entry or last_error_tinst_level
19028 is pointing at it. */
19034 }
19036 /* Adjust types before performing type deduction, as described in
19037 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
19038 sections are symmetric. PARM is the type of a function parameter
19039 or the return type of the conversion function. ARG is the type of
19040 the argument passed to the call, or the type of the value
19041 initialized with the result of the conversion function.
19042 ARG_EXPR is the original argument expression, which may be null. */
19044 static int
19048 tree arg_expr)
19049 {
19053 {
19058 /* Swap PARM and ARG throughout the remainder of this
19059 function; the handling is precisely symmetric since PARM
19060 will initialize ARG rather than vice versa. */
19065 /* Core issue #873: Do the DR606 thing (see below) for these cases,
19066 too, but here handle it by stripping the reference from PARM
19067 rather than by adding it to ARG. */
19075 /* Nothing else to do in this case. */
19080 }
19083 {
19084 /* [temp.deduct.call]
19086 If P is not a reference type:
19088 --If A is an array type, the pointer type produced by the
19089 array-to-pointer standard conversion (_conv.array_) is
19090 used in place of A for type deduction; otherwise,
19092 --If A is a function type, the pointer type produced by
19093 the function-to-pointer standard conversion
19094 (_conv.func_) is used in place of A for type deduction;
19095 otherwise,
19097 --If A is a cv-qualified type, the top level
19098 cv-qualifiers of A's type are ignored for type
19099 deduction. */
19104 else
19106 }
19108 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
19109 reference to a cv-unqualified template parameter that does not represent a
19110 template parameter of a class template (during class template argument
19111 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
19112 an lvalue, the type "lvalue reference to A" is used in place of A for type
19113 deduction. */
19120 /* try_one_overload doesn't provide an arg_expr, but
19121 functions are always lvalues. */
19125 /* [temp.deduct.call]
19127 If P is a cv-qualified type, the top level cv-qualifiers
19128 of P's type are ignored for type deduction. If P is a
19129 reference type, the type referred to by P is used for
19130 type deduction. */
19133 {
19136 }
19138 /* DR 322. For conversion deduction, remove a reference type on parm
19139 too (which has been swapped into ARG). */
19144 }
19146 /* Subroutine of unify_one_argument. PARM is a function parameter of a
19147 template which does contain any deducible template parameters; check if
19148 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
19149 unify_one_argument. */
19151 static int
19154 {
19155 tree type;
19159 else
19166 {
19170 }
19172 {
19177 }
19181 else
19183 }
19187 /* Returns true iff the expression EXPR is one from which a template
19188 argument can be deduced. In other words, if it's an undecorated
19189 use of a template non-type parameter. */
19191 static bool
19193 {
19194 /* Strip implicit conversions. */
19198 }
19200 /* Returns true iff the array domain DOMAIN uses a template parameter in a
19201 deducible way; that is, if it has a max value of <PARM> - 1. */
19203 static bool
19205 {
19214 }
19216 /* Returns true iff the template arguments ARGS use a template parameter
19217 in a deducible way. */
19219 static bool
19221 {
19223 {
19228 else
19229 {
19236 else
19238 }
19241 }
19243 }
19245 /* Returns true iff TYPE contains any deducible references to template
19246 parameters, as per 14.8.2.5. */
19248 static bool
19250 {
19254 /* T
19255 cv-list T
19256 TT<T>
19257 TT<i>
19258 TT<> */
19263 /* T*
19264 T&
19265 T&& */
19269 /* T[integer-constant ]
19270 type [i] */
19275 /* T type ::*
19276 type T::*
19277 T T::*
19278 T (type ::*)()
19279 type (T::*)()
19280 type (type ::*)(T)
19281 type (T::*)(T)
19282 T (type ::*)(T)
19283 T (T::*)()
19284 T (T::*)(T) */
19287 || (uses_deducible_template_parms
19290 /* template-name <T> (where template-name refers to a class template)
19291 template-name <i> (where template-name refers to a class template) */
19298 /* type (T)
19299 T()
19300 T(T) */
19303 {
19312 }
19315 }
19317 /* Subroutine of type_unification_real and unify_pack_expansion to
19318 handle unification of a single P/A pair. Parameters are as
19319 for those functions. */
19321 static int
19325 {
19332 /* We can't deduce anything from this, but we might get all the
19333 template args from other function args. */
19336 /* Implicit conversions (Clause 4) will be performed on a function
19337 argument to convert it to the type of the corresponding function
19338 parameter if the parameter type contains no template-parameters that
19339 participate in template argument deduction. */
19342 /* For function parameters with no deducible template parameters,
19343 just return. We'll check non-dependent conversions later. */
19347 {
19349 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
19350 | UNIFY_ALLOW_MORE_CV_QUAL
19364 }
19366 /* We only do these transformations if this is the top-level
19367 parameter_type_list in a call or declaration matching; in other
19368 situations (nested function declarators, template argument lists) we
19369 won't be comparing a type to an expression, and we don't do any type
19370 adjustments. */
19372 {
19374 {
19377 {
19378 /* [temp.deduct.type] A template-argument can be
19379 deduced from a pointer to function or pointer
19380 to member function argument if the set of
19381 overloaded functions does not contain function
19382 templates and at most one of a set of
19383 overloaded functions provides a unique
19384 match. */
19388 /* If a unique match was not found, this is a
19389 non-deduced context, so we still succeed. */
19391 }
19397 }
19399 arg_strict |=
19401 }
19402 else
19407 /* For deduction from an init-list we need the actual list. */
19411 }
19413 /* for_each_template_parm callback that always returns 0. */
19415 static int
19417 {
19419 }
19421 /* for_each_template_parm any_fn callback to handle deduction of a template
19422 type argument from the type of an array bound. */
19424 static int
19426 {
19434 {
19440 }
19442 /* Keep walking. */
19444 }
19446 /* Try to deduce any not-yet-deduced template type arguments from the type of
19447 an array bound. This is handled separately from unify because 14.8.2.5 says
19448 "The type of a type parameter is only deduced from an array bound if it is
19449 not otherwise deduced." */
19451 static void
19453 {
19458 }
19460 /* Most parms like fn_type_unification.
19462 If SUBR is 1, we're being called recursively (to unify the
19463 arguments of a function or method parameter of a function
19464 template).
19466 CHECKS is a pointer to a vector of access checks encountered while
19467 substituting default template arguments. */
19469 static int
19471 tree full_targs,
19472 tree xparms,
19476 unification_kind_t strict,
19480 {
19485 tree parms;
19496 /* Reset the number of non-defaulted template arguments contained
19497 in TARGS. */
19500 again:
19508 {
19513 /* For a function parameter pack that occurs at the end of the
19514 parameter-declaration-list, the type A of each remaining
19515 argument of the call is compared with the type P of the
19516 declarator-id of the function parameter pack. */
19522 /* For a function parameter pack that does not occur at the
19523 end of the parameter-declaration-list, the type of the
19524 parameter pack is a non-deduced context. */
19531 explain_p))
19533 }
19538 {
19539 /* Unify the remaining arguments with the pack expansion type. */
19540 tree argvec;
19543 /* Allocate a TREE_VEC and copy in all of the arguments */
19548 /* Copy the parameter into parmvec. */
19554 /* Advance to the end of the list of parameters. */
19556 }
19558 /* Fail if we've reached the end of the parm list, and more args
19559 are present, and the parm list isn't variadic. */
19562 /* Fail if parms are left and they don't have default values and
19563 they aren't all deduced as empty packs (c++/57397). This is
19564 consistent with sufficient_parms_p. */
19567 {
19571 do
19572 {
19575 count++;
19577 }
19581 type_pack_p);
19582 }
19585 {
19586 tsubst_flags_t complain = (explain_p
19587 ? tf_warning_or_error
19592 {
19596 /* Clear the "incomplete" flags on all argument packs now so that
19597 substituting them into later default arguments works. */
19599 {
19602 }
19610 {
19615 }
19617 /* If this is an undeduced nontype parameter that depends on
19618 a type parameter, try another pass; its type may have been
19619 deduced from a later argument than the one from which
19620 this parameter can be deduced. */
19624 {
19627 }
19629 /* Core issue #226 (C++0x) [temp.deduct]:
19631 If a template argument has not been deduced, its
19632 default template argument, if any, is used.
19634 When we are in C++98 mode, TREE_PURPOSE will either
19635 be NULL_TREE or ERROR_MARK_NODE, so we do not need
19636 to explicitly check cxx_dialect here. */
19638 /* OK, there is a default argument. Wait until after the
19639 conversion check to do substitution. */
19642 /* If the type parameter is a parameter pack, then it will
19643 be deduced to an empty parameter pack. */
19645 {
19646 tree arg;
19649 {
19652 }
19653 else
19660 }
19663 }
19665 /* DR 1391: All parameters have args, now check non-dependent parms for
19666 convertibility. */
19670 {
19676 /* For a function parameter pack that occurs at the end of the
19677 parameter-declaration-list, the type A of each remaining
19678 argument of the call is compared with the type P of the
19679 declarator-id of the function parameter pack. */
19685 /* For a function parameter pack that does not occur at the
19686 end of the parameter-declaration-list, the type of the
19687 parameter pack is a non-deduced context. */
19696 explain_p))
19698 }
19700 /* Now substitute into the default template arguments. */
19702 {
19726 else
19734 {
19736 /* The position of the first default template argument,
19737 is also the number of non-defaulted arguments in TARGS.
19738 Record that. */
19741 }
19742 }
19746 }
19752 }
19754 /* Subroutine of type_unification_real. Args are like the variables
19755 at the call site. ARG is an overloaded function (or template-id);
19756 we try deducing template args from each of the overloads, and if
19757 only one succeeds, we go with that. Modifies TARGS and returns
19758 true on success. */
19760 static bool
19762 tree targs,
19763 tree parm,
19764 tree arg,
19765 unification_kind_t strict,
19768 {
19775 {
19778 }
19779 else
19783 /* Handle `&x' where `x' is some static or non-static member
19784 function name. */
19790 /* Strip baselink information. */
19795 {
19796 /* If we got some explicit template args, we need to plug them into
19797 the affected templates before we try to unify, in case the
19798 explicit args will completely resolve the templates in question. */
19805 {
19818 {
19823 {
19826 }
19827 }
19830 }
19831 /* If no templates (or more than one) are fully resolved by the
19832 explicit arguments, this template-id is a non-deduced context; it
19833 could still be OK if we deduce all template arguments for the
19834 enclosing call through other arguments. */
19837 }
19840 /* If ARG is, for example, "(0, &f)" then its type will be unknown
19841 -- but the deduction does not succeed because the expression is
19842 not just the function on its own. */
19844 else
19846 {
19851 {
19854 }
19855 }
19857 /* [temp.deduct.type] A template-argument can be deduced from a pointer
19858 to function or pointer to member function argument if the set of
19859 overloaded functions does not contain function templates and at most
19860 one of a set of overloaded functions provides a unique match.
19862 So if we found multiple possibilities, we return success but don't
19863 deduce anything. */
19866 {
19870 {
19875 /* Don't forget explicit template arguments in a pack. */
19879 }
19880 }
19885 }
19887 /* Core DR 115: In contexts where deduction is done and fails, or in
19888 contexts where deduction is not done, if a template argument list is
19889 specified and it, along with any default template arguments, identifies
19890 a single function template specialization, then the template-id is an
19891 lvalue for the function template specialization. */
19893 tree
19895 {
19908 {
19911 }
19913 {
19916 }
19918 {
19921 }
19924 {
19928 /* If we got some explicit template args, we need to plug them into
19929 the affected templates before we try to unify, in case the
19930 explicit args will completely resolve the templates in question. */
19938 {
19951 {
19954 {
19957 }
19959 {
19962 }
19963 }
19964 }
19966 {
19974 {
19975 tree base
19978 }
19982 }
19984 /* There were no good options and at least one bad one, so let the
19985 user know what the problem is. */
19987 }
19989 }
19991 /* Subroutine of resolve_overloaded_unification; does deduction for a single
19992 overload. Fills TARGS with any deduced arguments, or error_mark_node if
19993 different overloads deduce different arguments for a given parm.
19994 ADDR_P is true if the expression for which deduction is being
19995 performed was of the form "& fn" rather than simply "fn".
19997 Returns 1 on success. */
19999 static int
20001 tree orig_targs,
20002 tree targs,
20003 tree parm,
20004 tree arg,
20005 unification_kind_t strict,
20009 {
20011 tree tempargs;
20017 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20018 to function or pointer to member function argument if the set of
20019 overloaded functions does not contain function templates and at most
20020 one of a set of overloaded functions provides a unique match.
20022 So if this is a template, just return success. */
20034 /* We don't copy orig_targs for this because if we have already deduced
20035 some template args from previous args, unify would complain when we
20036 try to deduce a template parameter for the same argument, even though
20037 there isn't really a conflict. */
20044 /* First make sure we didn't deduce anything that conflicts with
20045 explicitly specified args. */
20047 {
20054 /* Since we're unifying against ourselves, we will fill in
20055 template args used in the function parm list with our own
20056 template parms. Discard them. */
20059 {
20060 /* Check that the argument at each index of the deduced argument pack
20061 is equivalent to the corresponding explicitly specified argument.
20062 We may have deduced more arguments than were explicitly specified,
20063 and that's OK. */
20065 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
20066 that's wrong if we deduce the same argument pack from multiple
20067 function arguments: it's only incomplete the first time. */
20080 }
20083 }
20086 {
20091 }
20094 }
20096 /* PARM is a template class (perhaps with unbound template
20097 parameters). ARG is a fully instantiated type. If ARG can be
20098 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
20099 TARGS are as for unify. */
20101 static tree
20104 {
20105 tree copy_of_targs;
20115 /* We need to make a new template argument vector for the call to
20116 unify. If we used TARGS, we'd clutter it up with the result of
20117 the attempted unification, even if this class didn't work out.
20118 We also don't want to commit ourselves to all the unifications
20119 we've already done, since unification is supposed to be done on
20120 an argument-by-argument basis. In other words, consider the
20121 following pathological case:
20123 template <int I, int J, int K>
20124 struct S {};
20126 template <int I, int J>
20127 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
20129 template <int I, int J, int K>
20130 void f(S<I, J, K>, S<I, I, I>);
20132 void g() {
20133 S<0, 0, 0> s0;
20134 S<0, 1, 2> s2;
20136 f(s0, s2);
20137 }
20139 Now, by the time we consider the unification involving `s2', we
20140 already know that we must have `f<0, 0, 0>'. But, even though
20141 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
20142 because there are two ways to unify base classes of S<0, 1, 2>
20143 with S<I, I, I>. If we kept the already deduced knowledge, we
20144 would reject the possibility I=1. */
20148 {
20152 }
20154 /* If unification failed, we're done. */
20160 }
20162 /* Given a template type PARM and a class type ARG, find the unique
20163 base type in ARG that is an instance of PARM. We do not examine
20164 ARG itself; only its base-classes. If there is not exactly one
20165 appropriate base class, return NULL_TREE. PARM may be the type of
20166 a partial specialization, as well as a plain template type. Used
20167 by unify. */
20169 static enum template_base_result
20172 {
20174 tree binfo;
20180 {
20181 /* The type could not be completed. */
20184 }
20186 /* Walk in inheritance graph order. The search order is not
20187 important, and this avoids multiple walks of virtual bases. */
20189 {
20194 {
20195 /* If there is more than one satisfactory baseclass, then:
20197 [temp.deduct.call]
20199 If they yield more than one possible deduced A, the type
20200 deduction fails.
20202 applies. */
20204 {
20207 }
20210 }
20211 }
20215 }
20217 /* Returns the level of DECL, which declares a template parameter. */
20219 static int
20221 {
20223 {
20233 }
20235 }
20237 /* Decide whether ARG can be unified with PARM, considering only the
20238 cv-qualifiers of each type, given STRICT as documented for unify.
20239 Returns nonzero iff the unification is OK on that basis. */
20241 static int
20243 {
20249 {
20250 /* Although a CVR qualifier is ignored when being applied to a
20251 substituted template parameter ([8.3.2]/1 for example), that
20252 does not allow us to unify "const T" with "int&" because both
20253 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
20254 It is ok when we're allowing additional CV qualifiers
20255 at the outer level [14.8.2.1]/3,1st bullet. */
20265 }
20276 }
20278 /* Determines the LEVEL and INDEX for the template parameter PARM. */
20279 void
20281 {
20285 {
20288 }
20289 else
20290 {
20293 }
20294 }
20296 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
20297 do { \
20298 if (unify (TP, TA, P, A, S, EP)) \
20299 return 1; \
20300 } while (0)
20302 /* Unifies the remaining arguments in PACKED_ARGS with the pack
20303 expansion at the end of PACKED_PARMS. Returns 0 if the type
20304 deduction succeeds, 1 otherwise. STRICT is the same as in
20305 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
20306 function call argument list. We'll need to adjust the arguments to make them
20307 types. SUBR tells us if this is from a recursive call to
20308 type_unification_real, or for comparing two template argument
20309 lists. */
20311 static int
20315 {
20316 tree parm
20322 /* Add in any args remembered from an earlier partial instantiation. */
20329 /* Determine the parameter packs we will be deducing from the
20330 pattern, and record their current deductions. */
20333 {
20337 /* Determine the index and level of this parameter pack. */
20340 /* Keep track of the parameter packs and their corresponding
20341 argument packs. */
20344 }
20346 /* Loop through all of the arguments that have not yet been
20347 unified and unify each with the pattern. */
20349 {
20350 tree parm;
20354 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
20355 or the element of its argument pack at the current index if
20356 this argument was explicitly specified. */
20358 {
20367 {
20370 }
20372 }
20374 /* If we had explicit template arguments, substitute them into the
20375 pattern before deduction. */
20377 {
20378 /* Some arguments might still be unspecified or dependent. */
20386 NULL_TREE);
20391 }
20392 else
20395 /* Unify the pattern with the current argument. */
20397 explain_p))
20400 /* For each parameter pack, collect the deduced value. */
20402 {
20408 }
20409 }
20411 /* Verify that the results of unification with the parameter packs
20412 produce results consistent with what we've seen before, and make
20413 the deduced argument packs available. */
20415 {
20422 /* By default keep the original deduced argument pack.
20423 If necessary, more specific code is going to update the
20424 resulting deduced argument later down in this function. */
20428 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
20429 actually deduce anything. */
20437 {
20438 /* If we had fewer function args than explicit template args,
20439 just use the explicits. */
20444 }
20447 {
20448 tree result;
20449 /* Build the deduced *_ARGUMENT_PACK. */
20451 {
20454 }
20455 else
20460 /* Note the deduced argument packs for this parameter
20461 pack. */
20463 }
20467 {
20468 /* We only had the explicitly-provided arguments before, but
20469 now we have a complete set of arguments. */
20475 }
20476 else
20477 {
20483 /* Inconsistent unification of this parameter pack. */
20485 bad_old_arg,
20486 bad_new_arg);
20487 }
20488 }
20491 }
20493 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
20494 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
20495 parameters and return value are as for unify. */
20497 static int
20501 {
20502 tree parm_max;
20503 tree arg_max;
20507 /* Our representation of array types uses "N - 1" as the
20508 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
20509 not an integer constant. We cannot unify arbitrarily
20510 complex expressions, so we eliminate the MINUS_EXPRs
20511 here. */
20515 {
20518 }
20522 {
20523 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
20524 trying to unify the type of a variable with the type
20525 of a template parameter. For example:
20527 template <unsigned int N>
20528 void f (char (&) [N]);
20529 int g();
20530 void h(int i) {
20531 char a[g(i)];
20532 f(a);
20533 }
20535 Here, the type of the ARG will be "int [g(i)]", and
20536 may be a SAVE_EXPR, etc. */
20540 }
20542 /* If only one of the bounds used a MINUS_EXPR, compensate
20543 by adding one to the other bound. */
20546 integer_type_node,
20547 parm_max,
20548 integer_one_node);
20551 integer_type_node,
20552 arg_max,
20553 integer_one_node);
20557 }
20559 /* Returns whether T, a P or A in unify, is a type, template or expression. */
20563 static pa_kind_t
20565 {
20574 else
20576 }
20578 /* Deduce the value of template parameters. TPARMS is the (innermost)
20579 set of template parameters to a template. TARGS is the bindings
20580 for those template parameters, as determined thus far; TARGS may
20581 include template arguments for outer levels of template parameters
20582 as well. PARM is a parameter to a template function, or a
20583 subcomponent of that parameter; ARG is the corresponding argument.
20584 This function attempts to match PARM with ARG in a manner
20585 consistent with the existing assignments in TARGS. If more values
20586 are deduced, then TARGS is updated.
20588 Returns 0 if the type deduction succeeds, 1 otherwise. The
20589 parameter STRICT is a bitwise or of the following flags:
20591 UNIFY_ALLOW_NONE:
20592 Require an exact match between PARM and ARG.
20593 UNIFY_ALLOW_MORE_CV_QUAL:
20594 Allow the deduced ARG to be more cv-qualified (by qualification
20595 conversion) than ARG.
20596 UNIFY_ALLOW_LESS_CV_QUAL:
20597 Allow the deduced ARG to be less cv-qualified than ARG.
20598 UNIFY_ALLOW_DERIVED:
20599 Allow the deduced ARG to be a template base class of ARG,
20600 or a pointer to a template base class of the type pointed to by
20601 ARG.
20602 UNIFY_ALLOW_INTEGER:
20603 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
20604 case for more information.
20605 UNIFY_ALLOW_OUTER_LEVEL:
20606 This is the outermost level of a deduction. Used to determine validity
20607 of qualification conversions. A valid qualification conversion must
20608 have const qualified pointers leading up to the inner type which
20609 requires additional CV quals, except at the outer level, where const
20610 is not required [conv.qual]. It would be normal to set this flag in
20611 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
20612 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
20613 This is the outermost level of a deduction, and PARM can be more CV
20614 qualified at this point.
20615 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
20616 This is the outermost level of a deduction, and PARM can be less CV
20617 qualified at this point. */
20619 static int
20622 {
20624 tree targ;
20625 tree tparm;
20627 tsubst_flags_t complain = (explain_p
20628 ? tf_warning_or_error
20631 /* I don't think this will do the right thing with respect to types.
20632 But the only case I've seen it in so far has been array bounds, where
20633 signedness is the only information lost, and I think that will be
20634 okay. */
20642 /* We can't deduce anything from this, but we might get all the
20643 template args from other function args. */
20649 /* If PARM uses template parameters, then we can't bail out here,
20650 even if ARG == PARM, since we won't record unifications for the
20651 template parameters. We might need them if we're trying to
20652 figure out which of two things is more specialized. */
20656 /* Handle init lists early, so the rest of the function can assume
20657 we're dealing with a type. */
20659 {
20664 /* Replace T with std::initializer_list<T> for deduction. */
20671 /* We can only deduce from an initializer list argument if the
20672 parameter is std::initializer_list or an array; otherwise this
20673 is a non-deduced context. */
20678 else
20679 {
20681 /* Deduction is defined in terms of a single type, so just punt
20682 on the (bizarre) std::initializer_list<T...>. */
20685 }
20688 {
20695 {
20699 /* It should only be possible to get here for a call. */
20701 elt_strict |= maybe_adjust_types_for_deduction
20704 }
20707 explain_p);
20708 }
20712 {
20713 /* Also deduce from the length of the initializer list. */
20720 }
20722 /* If the std::initializer_list<T> deduction worked, replace the
20723 deduced A with std::initializer_list<A>. */
20725 {
20730 }
20732 }
20734 /* If parm and arg aren't the same kind of thing (template, type, or
20735 expression), fail early. */
20739 /* Immediately reject some pairs that won't unify because of
20740 cv-qualification mismatches. */
20743 /* It is the elements of the array which hold the cv quals of an array
20744 type, and the elements might be template type parms. We'll check
20745 when we recurse. */
20747 /* We check the cv-qualifiers when unifying with template type
20748 parameters below. We want to allow ARG `const T' to unify with
20749 PARM `T' for example, when computing which of two templates
20750 is more specialized, for example. */
20764 {
20768 /* In a type which contains a nested-name-specifier, template
20769 argument values cannot be deduced for template parameters used
20770 within the nested-name-specifier. */
20782 /* The PARM is not one we're trying to unify. Just check
20783 to see if it matches ARG. */
20784 {
20789 else
20791 }
20798 /* Check for mixed types and values. */
20806 {
20809 {
20810 /* First try to match ARG directly. */
20812 explain_p);
20814 {
20815 /* Otherwise, look for a suitable base of ARG, as below. */
20822 }
20823 }
20824 /* ARG must be constructed from a template class or a template
20825 template parameter. */
20830 /* Deduce arguments T, i from TT<T> or TT<i>. */
20836 /* Fall through to deduce template name. */
20837 }
20841 {
20842 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
20844 /* Simple cases: Value already set, does match or doesn't. */
20849 }
20850 else
20851 {
20852 /* If PARM is `const T' and ARG is only `int', we don't have
20853 a match unless we are allowing additional qualification.
20854 If ARG is `const int' and PARM is just `T' that's OK;
20855 that binds `const int' to `T'. */
20860 /* Consider the case where ARG is `const volatile int' and
20861 PARM is `const T'. Then, T should be `volatile int'. */
20862 arg = cp_build_qualified_type_real
20867 /* Simple cases: Value already set, does match or doesn't. */
20873 /* Make sure that ARG is not a variable-sized array. (Note
20874 that were talking about variable-sized arrays (like
20875 `int[n]'), rather than arrays of unknown size (like
20876 `int[]').) We'll get very confused by such a type since
20877 the bound of the array is not constant, and therefore
20878 not mangleable. Besides, such types are not allowed in
20879 ISO C++, so we can do as we please here. We do allow
20880 them for 'auto' deduction, since that isn't ABI-exposed. */
20884 /* Strip typedefs as in convert_template_argument. */
20886 }
20888 /* If ARG is a parameter pack or an expansion, we cannot unify
20889 against it unless PARM is also a parameter pack. */
20894 /* If the argument deduction results is a METHOD_TYPE,
20895 then there is a problem.
20896 METHOD_TYPE doesn't map to any real C++ type the result of
20897 the deduction can not be of that type. */
20911 {
20912 /* The PARM is not one we're trying to unify. Just check
20913 to see if it matches ARG. */
20919 }
20925 {
20929 /* We're deducing from an array bound, the type doesn't matter. */
20935 }
20937 /* [temp.deduct.type] If, in the declaration of a function template
20938 with a non-type template-parameter, the non-type
20939 template-parameter is used in an expression in the function
20940 parameter-list and, if the corresponding template-argument is
20941 deduced, the template-argument type shall match the type of the
20942 template-parameter exactly, except that a template-argument
20943 deduced from an array bound may be of any integral type.
20944 The non-type parameter might use already deduced type parameters. */
20949 {
20953 }
20956 /* Template-parameter dependent expression. Just accept it for now.
20957 It will later be processed in convert_template_argument. */
20958 ;
20964 /* Convert the ARG to the type of PARM; the deduced non-type
20965 template argument must exactly match the types of the
20966 corresponding parameter. */
20969 {
20970 /* We haven't deduced the type of this parameter yet. */
20972 /* We deduce from array bounds in try_array_deduction. */
20974 {
20975 /* Deduce it from the non-type argument. */
20980 }
20981 else
20982 /* Try again later. */
20984 }
20985 else
20988 /* If ARG is a parameter pack or an expansion, we cannot unify
20989 against it unless PARM is also a parameter pack. */
20994 {
20997 }
21002 {
21003 /* A pointer-to-member constant can be unified only with
21004 another constant. */
21008 /* Just unify the class member. It would be useless (and possibly
21009 wrong, depending on the strict flags) to unify also
21010 PTRMEM_CST_CLASS, because we want to be sure that both parm and
21011 arg refer to the same variable, even if through different
21012 classes. For instance:
21014 struct A { int x; };
21015 struct B : A { };
21017 Unification of &A::x and &B::x must succeed. */
21020 }
21023 {
21027 /* [temp.deduct.call]
21029 A can be another pointer or pointer to member type that can
21030 be converted to the deduced A via a qualification
21031 conversion (_conv.qual_).
21033 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
21034 This will allow for additional cv-qualification of the
21035 pointed-to types if appropriate. */
21038 /* The derived-to-base conversion only persists through one
21039 level of pointers. */
21044 }
21076 /* We have already checked cv-qualification at the top of the
21077 function. */
21081 /* As far as unification is concerned, this wins. Later checks
21082 will invalidate it if necessary. */
21085 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
21086 /* Type INTEGER_CST can come from ordinary constant template args. */
21098 {
21108 /* Check for pack expansions in the parameters. */
21110 {
21112 {
21114 /* We can unify against something with a trailing
21115 parameter pack. */
21117 else
21118 /* [temp.deduct.type]/9: If the template argument list of
21119 P contains a pack expansion that is not the last
21120 template argument, the entire template argument list
21121 is a non-deduced context. */
21123 }
21124 }
21126 /* If we don't have enough arguments to satisfy the parameters
21127 (not counting the pack expression at the end), or we have
21128 too many arguments for a parameter list that doesn't end in
21129 a pack expression, we can't unify. */
21135 /* Unify all of the parameters that precede the (optional)
21136 pack expression. */
21138 {
21143 }
21146 DEDUCE_EXACT,
21149 }
21157 {
21165 }
21170 {
21174 {
21175 /* First, we try to unify the PARM and ARG directly. */
21180 {
21181 /* Fallback to the special case allowed in
21182 [temp.deduct.call]:
21184 If P is a class, and P has the form
21185 template-id, then A can be a derived class of
21186 the deduced A. Likewise, if P is a pointer to
21187 a class of the form template-id, A can be a
21188 pointer to a derived class pointed to by the
21189 deduced A. */
21195 {
21196 /* Don't give the derived diagnostic if we're
21197 already dealing with the same template. */
21198 bool same_template
21204 }
21205 }
21206 }
21210 /* Perhaps PARM is something like S<U> and ARG is S<int>.
21211 Then, we should unify `int' and `U'. */
21213 else
21214 /* There's no chance of unification succeeding. */
21219 }
21226 {
21229 tree a;
21235 /* CV qualifications for methods can never be deduced, they must
21236 match exactly. We need to check them explicitly here,
21237 because type_unification_real treats them as any other
21238 cv-qualified parameter. */
21240 && (!check_cv_quals_for_unify
21268 {
21280 }
21283 }
21286 /* Unify a pointer to member with a pointer to member function, which
21287 deduces the type of the member as a function type. */
21289 {
21290 /* Check top-level cv qualifiers */
21298 /* Determine the type of the function we are unifying against. */
21302 }
21321 /* Matched cases are handled by the ARG == PARM test above. */
21325 /* We might get a variable as a non-type template argument in parm if the
21326 corresponding parameter is type-dependent. Make any necessary
21327 adjustments based on whether arg is a reference. */
21331 {
21336 }
21337 /* Now use the normal expression code to check whether they match. */
21348 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
21349 or UNDERLYING_TYPE nodes. */
21353 /* Unification fails if we hit an error node. */
21358 {
21368 }
21369 /* FALLTHRU */
21372 /* An unresolved overload is a nondeduced context. */
21376 expr:
21377 /* We must be looking at an expression. This can happen with
21378 something like:
21380 template <int I>
21381 void foo(S<I>, S<I + 2>);
21383 This is a "nondeduced context":
21385 [deduct.type]
21387 The nondeduced contexts are:
21389 --A type that is a template-id in which one or more of
21390 the template-arguments is an expression that references
21391 a template-parameter.
21393 In these cases, we assume deduction succeeded, but don't
21394 actually infer any unifications. */
21399 else
21401 }
21402 }
21403 #undef RECUR_AND_CHECK_FAILURE
21404 \f
21405 /* Note that DECL can be defined in this translation unit, if
21406 required. */
21408 static void
21410 {
21411 tree clone;
21415 }
21417 /* Called if RESULT is explicitly instantiated, or is a member of an
21418 explicitly instantiated class. */
21420 void
21422 {
21425 /* If this entity has already been written out, it's too late to
21426 make any modifications. */
21430 /* For anonymous namespace we don't need to do anything. */
21432 {
21435 }
21438 /* The TREE_PUBLIC flag for function declarations will have been
21439 set correctly by tsubst. */
21442 /* This might have been set by an earlier implicit instantiation. */
21447 else
21448 {
21451 /* Always make artificials weak. */
21454 /* For WIN32 we also want to put explicit instantiations in
21455 linkonce sections. */
21458 }
21460 /* If EXTERN_P, then this function will not be emitted -- unless
21461 followed by an explicit instantiation, at which point its linkage
21462 will be adjusted. If !EXTERN_P, then this function will be
21463 emitted here. In neither circumstance do we want
21464 import_export_decl to adjust the linkage. */
21466 }
21468 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
21469 important template arguments. If any are missing, we check whether
21470 they're important by using error_mark_node for substituting into any
21471 args that were used for partial ordering (the ones between ARGS and END)
21472 and seeing if it bubbles up. */
21474 static bool
21476 {
21481 {
21484 }
21486 {
21490 }
21492 }
21494 /* Given two function templates PAT1 and PAT2, return:
21496 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
21497 -1 if PAT2 is more specialized than PAT1.
21498 0 if neither is more specialized.
21500 LEN indicates the number of parameters we should consider
21501 (defaulted parameters should not be considered).
21503 The 1998 std underspecified function template partial ordering, and
21504 DR214 addresses the issue. We take pairs of arguments, one from
21505 each of the templates, and deduce them against each other. One of
21506 the templates will be more specialized if all the *other*
21507 template's arguments deduce against its arguments and at least one
21508 of its arguments *does* *not* deduce against the other template's
21509 corresponding argument. Deduction is done as for class templates.
21510 The arguments used in deduction have reference and top level cv
21511 qualifiers removed. Iff both arguments were originally reference
21512 types *and* deduction succeeds in both directions, an lvalue reference
21513 wins against an rvalue reference and otherwise the template
21514 with the more cv-qualified argument wins for that pairing (if
21515 neither is more cv-qualified, they both are equal). Unlike regular
21516 deduction, after all the arguments have been deduced in this way,
21517 we do *not* verify the deduced template argument values can be
21518 substituted into non-deduced contexts.
21520 The logic can be a bit confusing here, because we look at deduce1 and
21521 targs1 to see if pat2 is at least as specialized, and vice versa; if we
21522 can find template arguments for pat1 to make arg1 look like arg2, that
21523 means that arg2 is at least as specialized as arg1. */
21525 int
21527 {
21540 /* Remove the this parameter from non-static member functions. If
21541 one is a non-static member function and the other is not a static
21542 member function, remove the first parameter from that function
21543 also. This situation occurs for operator functions where we
21544 locate both a member function (with this pointer) and non-member
21545 operator (with explicit first operand). */
21547 {
21552 }
21554 {
21557 {
21558 len--;
21560 }
21561 }
21563 /* If only one is a conversion operator, they are unordered. */
21567 /* Consider the return type for a conversion function */
21569 {
21572 len++;
21573 }
21575 processing_template_decl++;
21581 /* Stop when an ellipsis is seen. */
21583 {
21594 {
21595 /* When both arguments are pack expansions, we need only
21596 unify the patterns themselves. */
21600 /* This is the last comparison we need to do. */
21602 }
21604 /* DR 1847: If a particular P contains no template-parameters that
21605 participate in template argument deduction, that P is not used to
21606 determine the ordering. */
21612 {
21616 }
21619 {
21623 }
21629 {
21635 /* Setup the parameter vector, which contains only ARG1. */
21638 /* Setup the argument vector, which contains the remaining
21639 arguments. */
21648 /* We cannot deduce in the other direction, because ARG1 is
21649 a pack expansion but ARG2 is not. */
21651 }
21653 {
21659 /* Setup the parameter vector, which contains only ARG1. */
21662 /* Setup the argument vector, which contains the remaining
21663 arguments. */
21672 /* We cannot deduce in the other direction, because ARG2 is
21673 a pack expansion but ARG1 is not.*/
21675 }
21677 else
21678 {
21679 /* The normal case, where neither argument is a pack
21680 expansion. */
21687 }
21689 /* If we couldn't deduce arguments for tparms1 to make arg1 match
21690 arg2, then arg2 is not as specialized as arg1. */
21696 /* "If, for a given type, deduction succeeds in both directions
21697 (i.e., the types are identical after the transformations above)
21698 and both P and A were reference types (before being replaced with
21699 the type referred to above):
21700 - if the type from the argument template was an lvalue reference and
21701 the type from the parameter template was not, the argument type is
21702 considered to be more specialized than the other; otherwise,
21703 - if the type from the argument template is more cv-qualified
21704 than the type from the parameter template (as described above),
21705 the argument type is considered to be more specialized than the other;
21706 otherwise,
21707 - neither type is more specialized than the other." */
21710 {
21712 {
21715 else
21717 }
21719 {
21724 }
21725 }
21728 /* We've failed to deduce something in either direction.
21729 These must be unordered. */
21732 next:
21736 /* We have already processed all of the arguments in our
21737 handing of the pack expansion type. */
21742 }
21744 /* "In most cases, all template parameters must have values in order for
21745 deduction to succeed, but for partial ordering purposes a template
21746 parameter may remain without a value provided it is not used in the
21747 types being used for partial ordering."
21749 Thus, if we are missing any of the targs1 we need to substitute into
21750 origs1, then pat2 is not as specialized as pat1. This can happen when
21751 there is a nondeduced context. */
21757 processing_template_decl--;
21759 /* If both deductions succeed, the partial ordering selects the more
21760 constrained template. */
21762 {
21767 }
21769 /* All things being equal, if the next argument is a pack expansion
21770 for one function but not for the other, prefer the
21771 non-variadic function. FIXME this is bogus; see c++/41958. */
21775 {
21778 }
21784 else
21786 }
21788 /* Determine which of two partial specializations of TMPL is more
21789 specialized.
21791 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
21792 to the first partial specialization. The TREE_PURPOSE is the
21793 innermost set of template parameters for the partial
21794 specialization. PAT2 is similar, but for the second template.
21796 Return 1 if the first partial specialization is more specialized;
21797 -1 if the second is more specialized; 0 if neither is more
21798 specialized.
21800 See [temp.class.order] for information about determining which of
21801 two templates is more specialized. */
21803 static int
21805 {
21806 tree targs;
21815 /* Just like what happens for functions, if we are ordering between
21816 different template specializations, we may encounter dependent
21817 types in the arguments, and we need our dependency check functions
21818 to behave correctly. */
21822 {
21825 }
21829 {
21832 }
21835 /* If both deductions succeed, the partial ordering selects the more
21836 constrained template. */
21840 /* In the case of a tie where at least one of the templates
21841 has a parameter pack at the end, the template with the most
21842 non-packed parameters wins. */
21844 && any_deductions
21847 {
21853 /* We don't count the pack expansion at the end. */
21863 }
21866 }
21868 /* Return the template arguments that will produce the function signature
21869 DECL from the function template FN, with the explicit template
21870 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
21871 also match. Return NULL_TREE if no satisfactory arguments could be
21872 found. */
21874 static tree
21876 {
21880 tree decl_arg_types;
21883 tree arg;
21887 /* Never do unification on the 'this' parameter. */
21908 }
21910 /* Return the innermost template arguments that, when applied to a partial
21911 specialization SPEC_TMPL of TMPL, yield the ARGS.
21913 For example, suppose we have:
21915 template <class T, class U> struct S {};
21916 template <class T> struct S<T*, int> {};
21918 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
21919 partial specialization and the ARGS will be {double*, int}. The resulting
21920 vector will be {double}, indicating that `T' is bound to `double'. */
21922 static tree
21924 {
21926 tree spec_args
21929 tree deduced_args;
21930 tree innermost_deduced_args;
21934 {
21938 innermost_deduced_args);
21939 }
21940 else
21944 again:
21953 {
21955 {
21961 }
21963 }
21967 {
21970 }
21972 /* Verify that nondeduced template arguments agree with the type
21973 obtained from argument deduction.
21975 For example:
21977 struct A { typedef int X; };
21978 template <class T, class U> struct C {};
21979 template <class T> struct C<T, typename T::X> {};
21981 Then with the instantiation `C<A, int>', we can deduce that
21982 `T' is `A' but unify () does not check whether `typename T::X'
21983 is `int'. */
21994 /* We only need to check the innermost arguments; the other
21995 arguments will always agree. */
22000 /* Now that we have bindings for all of the template arguments,
22001 ensure that the arguments deduced for the template template
22002 parameters have compatible template parameter lists. See the use
22003 of template_template_parm_bindings_ok_p in fn_type_unification
22004 for more information. */
22009 }
22011 // Compare two function templates T1 and T2 by deducing bindings
22012 // from one against the other. If both deductions succeed, compare
22013 // constraints to see which is more constrained.
22014 static int
22016 {
22021 {
22024 }
22027 {
22030 }
22032 // If both deductions succeed, then one may be more constrained.
22037 }
22039 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
22040 Return the TREE_LIST node with the most specialized template, if
22041 any. If there is no most specialized template, the error_mark_node
22042 is returned.
22044 Note that this function does not look at, or modify, the
22045 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
22046 returned is one of the elements of INSTANTIATIONS, callers may
22047 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
22048 and retrieve it from the value returned. */
22050 tree
22052 {
22059 {
22065 {
22066 /* Equally specialized, move to next function. If there
22067 is no next function, nothing's most specialized. */
22072 }
22073 }
22076 /* Now verify that champ is better than everything earlier in the
22077 instantiation list. */
22080 {
22083 }
22084 }
22086 processing_template_decl--;
22092 }
22094 /* If DECL is a specialization of some template, return the most
22095 general such template. Otherwise, returns NULL_TREE.
22097 For example, given:
22099 template <class T> struct S { template <class U> void f(U); };
22101 if TMPL is `template <class U> void S<int>::f(U)' this will return
22102 the full template. This function will not trace past partial
22103 specializations, however. For example, given in addition:
22105 template <class T> struct S<T*> { template <class U> void f(U); };
22107 if TMPL is `template <class U> void S<int*>::f(U)' this will return
22108 `template <class T> template <class U> S<T*>::f(U)'. */
22110 tree
22112 {
22114 {
22117 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
22118 template friend, or a FIELD_DECL for a capture pack. */
22121 }
22123 /* Look for more and more general templates. */
22125 {
22126 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
22127 (See cp-tree.h for details.) */
22136 /* Stop if we run into an explicitly specialized class template. */
22143 }
22146 }
22148 /* Return the most specialized of the template partial specializations
22149 which can produce TARGET, a specialization of some class or variable
22150 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
22151 a TEMPLATE_DECL node corresponding to the partial specialization, while
22152 the TREE_PURPOSE is the set of template arguments that must be
22153 substituted into the template pattern in order to generate TARGET.
22155 If the choice of partial specialization is ambiguous, a diagnostic
22156 is issued, and the error_mark_node is returned. If there are no
22157 partial specializations matching TARGET, then NULL_TREE is
22158 returned, indicating that the primary template should be used. */
22160 static tree
22162 {
22164 tree t;
22165 tree champ;
22172 {
22176 }
22178 {
22181 }
22183 {
22187 }
22188 else
22193 /* For determining which partial specialization to use, only the
22194 innermost args are interesting. */
22196 {
22199 }
22202 {
22203 tree spec_args;
22207 {
22208 /* Substitute in the template args from the enclosing class. */
22212 }
22219 {
22223 /* Keep the candidate only if the constraints are satisfied,
22224 or if we're not compiling with concepts. */
22227 {
22230 }
22231 }
22232 }
22242 {
22245 ;
22246 else
22247 {
22249 {
22252 {
22255 }
22256 }
22258 }
22259 }
22263 {
22266 {
22269 }
22270 }
22273 {
22280 else
22284 {
22289 }
22292 }
22295 }
22297 /* Explicitly instantiate DECL. */
22299 void
22301 {
22306 /* An error occurred, for which grokdeclarator has already issued
22307 an appropriate message. */
22310 {
22313 }
22319 {
22320 /* There is an asymmetry here in the way VAR_DECLs and
22321 FUNCTION_DECLs are handled by grokdeclarator. In the case of
22322 the latter, the DECL we get back will be marked as a
22323 template instantiation, and the appropriate
22324 DECL_TEMPLATE_INFO will be set up. This does not happen for
22325 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
22326 should handle VAR_DECLs as it currently handles
22327 FUNCTION_DECLs. */
22329 {
22332 }
22335 {
22338 }
22340 {
22345 }
22346 }
22348 {
22351 }
22352 else
22355 /* Check for various error cases. Note that if the explicit
22356 instantiation is valid the RESULT will currently be marked as an
22357 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
22358 until we get here. */
22361 {
22362 /* DR 259 [temp.spec].
22364 Both an explicit instantiation and a declaration of an explicit
22365 specialization shall not appear in a program unless the explicit
22366 instantiation follows a declaration of the explicit specialization.
22368 For a given set of template parameters, if an explicit
22369 instantiation of a template appears after a declaration of an
22370 explicit specialization for that template, the explicit
22371 instantiation has no effect. */
22373 }
22375 {
22376 /* [temp.spec]
22378 No program shall explicitly instantiate any template more
22379 than once.
22381 We check DECL_NOT_REALLY_EXTERN so as not to complain when
22382 the first instantiation was `extern' and the second is not,
22383 and EXTERN_P for the opposite case. */
22386 /* If an "extern" explicit instantiation follows an ordinary
22387 explicit instantiation, the template is instantiated. */
22390 }
22392 {
22395 }
22397 {
22400 }
22403 ;
22405 {
22408 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
22411 }
22412 else
22420 }
22422 static void
22424 {
22430 {
22433 }
22434 }
22436 /* Called from do_type_instantiation through binding_table_foreach to
22437 do recursive instantiation for the type bound in ENTRY. */
22438 static void
22440 {
22446 }
22448 /* Perform an explicit instantiation of template class T. STORAGE, if
22449 non-null, is the RID for extern, inline or static. COMPLAIN is
22450 nonzero if this is called from the parser, zero if called recursively,
22451 since the standard is unclear (as detailed below). */
22453 void
22455 {
22465 {
22466 tree tmpl =
22470 else
22473 }
22478 {
22481 t);
22483 }
22486 {
22488 {
22490 {
22493 "ISO C++ 1998 forbids the use of %<extern%> on "
22495 }
22496 else
22498 "ISO C++ forbids the use of %qE"
22500 }
22508 else
22509 {
22511 storage);
22513 }
22514 }
22517 {
22518 /* DR 259 [temp.spec].
22520 Both an explicit instantiation and a declaration of an explicit
22521 specialization shall not appear in a program unless the explicit
22522 instantiation follows a declaration of the explicit specialization.
22524 For a given set of template parameters, if an explicit
22525 instantiation of a template appears after a declaration of an
22526 explicit specialization for that template, the explicit
22527 instantiation has no effect. */
22529 }
22531 {
22532 /* [temp.spec]
22534 No program shall explicitly instantiate any template more
22535 than once.
22537 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
22538 instantiation was `extern'. If EXTERN_P then the second is.
22539 These cases are OK. */
22546 /* If we've already instantiated the template, just return now. */
22549 }
22557 /* In contrast to implicit instantiation, where only the
22558 declarations, and not the definitions, of members are
22559 instantiated, we have here:
22561 [temp.explicit]
22563 The explicit instantiation of a class template specialization
22564 implies the instantiation of all of its members not
22565 previously explicitly specialized in the translation unit
22566 containing the explicit instantiation.
22568 Of course, we can't instantiate member template classes, since we
22569 don't have any arguments for them. Note that the standard is
22570 unclear on whether the instantiation of the members are
22571 *explicit* instantiations or not. However, the most natural
22572 interpretation is that it should be an explicit
22573 instantiation. */
22577 && !static_p
22580 {
22585 }
22590 }
22592 /* Given a function DECL, which is a specialization of TMPL, modify
22593 DECL to be a re-instantiation of TMPL with the same template
22594 arguments. TMPL should be the template into which tsubst'ing
22595 should occur for DECL, not the most general template.
22597 One reason for doing this is a scenario like this:
22599 template <class T>
22600 void f(const T&, int i);
22602 void g() { f(3, 7); }
22604 template <class T>
22605 void f(const T& t, const int i) { }
22607 Note that when the template is first instantiated, with
22608 instantiate_template, the resulting DECL will have no name for the
22609 first parameter, and the wrong type for the second. So, when we go
22610 to instantiate the DECL, we regenerate it. */
22612 static void
22614 {
22615 /* The arguments used to instantiate DECL, from the most general
22616 template. */
22617 tree code_pattern;
22621 /* Make sure that we can see identifiers, and compute access
22622 correctly. */
22626 {
22627 tree decl_parm;
22628 tree pattern_parm;
22629 tree specs;
22643 specs);
22645 /* Merge parameter declarations. */
22648 pattern_parm
22652 {
22653 tree parm_type;
22654 tree attributes;
22659 NULL_TREE);
22665 {
22668 }
22671 }
22672 /* Merge any parameters that match with the function parameter
22673 pack. */
22675 {
22677 tree expanded_types;
22678 /* Expand the TYPE_PACK_EXPANSION that provides the types for
22679 the parameters in this function parameter pack. */
22684 {
22685 tree parm_type;
22686 tree attributes;
22689 /* Rename the parameter to include the index. */
22698 {
22701 }
22703 }
22704 }
22705 /* Merge additional specifiers from the CODE_PATTERN. */
22709 }
22711 {
22721 }
22722 else
22726 }
22728 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
22729 substituted to get DECL. */
22731 tree
22733 {
22736 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
22737 for the instantiation. This is not always the most general
22738 template. Consider, for example:
22740 template <class T>
22741 struct S { template <class U> void f();
22742 template <> void f<int>(); };
22744 and an instantiation of S<double>::f<int>. We want TD to be the
22745 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
22747 more general template. */
22749 /* We must also deal with friend templates. Given:
22751 template <class T> struct S {
22752 template <class U> friend void f() {};
22753 };
22755 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
22756 so far as the language is concerned, but that's still
22757 where we get the pattern for the instantiation from. On
22758 other hand, if the definition comes outside the class, say:
22760 template <class T> struct S {
22761 template <class U> friend void f();
22762 };
22763 template <class U> friend void f() {}
22765 we don't need to look any further. That's what the check for
22766 DECL_INITIAL is for. */
22770 {
22771 /* The present template, TD, should not be a definition. If it
22772 were a definition, we should be using it! Note that we
22773 cannot restructure the loop to just keep going until we find
22774 a template with a definition, since that might go too far if
22775 a specialization was declared, but not defined. */
22777 /* Fetch the more general template. */
22779 }
22782 }
22784 /* Returns true if we need to instantiate this template instance even if we
22785 know we aren't going to emit it. */
22787 bool
22789 {
22790 /* We always instantiate inline functions so that we can inline them. An
22791 explicit instantiation declaration prohibits implicit instantiation of
22792 non-inline functions. With high levels of optimization, we would
22793 normally inline non-inline functions -- but we're not allowed to do
22794 that for "extern template" functions. Therefore, we check
22795 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
22799 /* And we need to instantiate static data members so that
22800 their initializers are available in integral constant
22801 expressions. */
22804 }
22806 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
22807 instantiate it now, modifying TREE_TYPE (fn). Returns false on
22808 error, true otherwise. */
22810 bool
22812 {
22815 /* Don't instantiate a noexcept-specification from template context. */
22830 {
22836 {
22837 /* If hash_set::add returns true, the element was already there. */
22842 fn);
22844 }
22846 {
22861 }
22862 else
22872 }
22875 {
22878 else
22880 }
22883 }
22885 /* We're starting to process the function INST, an instantiation of PATTERN;
22886 add their parameters to local_specializations. */
22888 static void
22890 {
22894 {
22898 }
22900 {
22902 {
22905 }
22906 else
22907 {
22908 /* Register the (value) argument pack as a specialization of
22909 TMPL_PARM, then move on. */
22912 }
22913 }
22915 }
22917 /* Produce the definition of D, a _DECL generated from a template. If
22918 DEFER_OK is true, then we don't have to actually do the
22919 instantiation now; we just have to do it sometime. Normally it is
22920 an error if this is an explicit instantiation but D is undefined.
22921 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
22922 instantiated class template. */
22924 tree
22926 {
22928 tree gen_args;
22929 tree args;
22930 tree td;
22931 tree code_pattern;
22932 tree spec;
22933 tree gen_tmpl;
22941 /* This function should only be used to instantiate templates for
22942 functions and static member variables. */
22945 /* A concept is never instantiated. */
22948 /* Variables are never deferred; if instantiation is required, they
22949 are instantiated right away. That allows for better code in the
22950 case that an expression refers to the value of the variable --
22951 if the variable has a constant value the referring expression can
22952 take advantage of that fact. */
22956 /* Don't instantiate cloned functions. Instead, instantiate the
22957 functions they cloned. */
22965 /* D has already been instantiated or explicitly specialized, so
22966 there's nothing for us to do here.
22968 It might seem reasonable to check whether or not D is an explicit
22969 instantiation, and, if so, stop here. But when an explicit
22970 instantiation is deferred until the end of the compilation,
22971 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
22972 the instantiation. */
22975 /* Check to see whether we know that this template will be
22976 instantiated in some other file, as with "extern template"
22977 extension. */
22980 /* In general, we do not instantiate such templates. */
22988 /* We should already have the extra args. */
22991 /* And what's in the hash table should match D. */
22995 /* This needs to happen before any tsubsting. */
23001 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
23002 for the instantiation. */
23007 {
23008 /* Look up an explicit specialization, if any. */
23012 {
23015 }
23016 }
23020 /* We should never be trying to instantiate a member of a class
23021 template or partial specialization. */
23026 /* In the case of a friend template whose definition is provided
23027 outside the class, we may have too many arguments. Drop the
23028 ones we don't need. The same is true for specializations. */
23029 args = get_innermost_template_args
23033 {
23039 }
23040 else
23041 {
23046 else
23048 }
23050 /* We may be in the middle of deferred access check. Disable it now. */
23053 /* Unless an explicit instantiation directive has already determined
23054 the linkage of D, remember that a definition is available for
23055 this entity. */
23065 /* If D is a member of an explicitly instantiated class template,
23066 and no definition is available, treat it like an implicit
23067 instantiation. */
23070 {
23071 /* Leave linkage flags alone on instantiations with anonymous
23072 visibility. */
23074 {
23077 }
23079 }
23081 /* Defer all other templates, unless we have been explicitly
23082 forbidden from doing so. */
23084 template. */
23085 ! pattern_defined
23086 /* If it's OK to postpone instantiation, do so. */
23087 || defer_ok
23088 /* If this is a static data member that will be defined
23089 elsewhere, we don't want to instantiate the entire data
23090 member, but we do want to instantiate the initializer so that
23091 we can substitute that elsewhere. */
23093 /* Handle here a deleted function too, avoid generating
23094 its body (c++/61080). */
23096 {
23097 /* The definition of the static data member is now required so
23098 we must substitute the initializer. */
23102 {
23103 tree ns;
23104 tree init;
23113 args,
23116 /* If instantiating the initializer involved instantiating this
23117 again, don't call cp_finish_decl twice. */
23119 {
23120 /* Make sure the initializer is still constant, in case of
23121 circular dependency (template/instantiate6.C). */
23122 const_init
23126 LOOKUP_ONLYCONVERTING);
23127 }
23131 }
23133 /* We restore the source position here because it's used by
23134 add_pending_template. */
23140 /* [temp.explicit]
23142 The definition of a non-exported function template, a
23143 non-exported member function template, or a non-exported
23144 member function or static data member of a class template
23145 shall be present in every translation unit in which it is
23146 explicitly instantiated. */
23150 /* If we're in unevaluated context, we just wanted to get the
23151 constant value; this isn't an odr use, so don't queue
23152 a full instantiation. */
23155 /* ??? Historically, we have instantiated inline functions, even
23156 when marked as "extern template". */
23160 }
23161 /* Tell the repository that D is available in this translation unit
23162 -- and see if it is supposed to be instantiated here. */
23164 {
23165 /* In a PCH file, despite the fact that the repository hasn't
23166 requested instantiation in the PCH it is still possible that
23167 an instantiation will be required in a file that includes the
23168 PCH. */
23171 /* Instantiate inline functions so that the inliner can do its
23172 job, even though we'll not be emitting a copy of this
23173 function. */
23176 }
23179 tree fn_context;
23190 else
23191 {
23195 }
23197 /* Mark D as instantiated so that recursive calls to
23198 instantiate_decl do not try to instantiate it again. */
23201 /* Regenerate the declaration in case the template has been modified
23202 by a subsequent redeclaration. */
23205 /* We already set the file and line above. Reset them now in case
23206 they changed as a result of calling regenerate_decl_from_template. */
23210 {
23211 tree init;
23214 /* Clear out DECL_RTL; whatever was there before may not be right
23215 since we've reset the type of the declaration. */
23219 /* The initializer is placed in DECL_INITIAL by
23220 regenerate_decl_from_template so we don't need to
23221 push/pop_access_scope again here. Pull it out so that
23222 cp_finish_decl can process it. */
23227 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
23228 initializer. That function will defer actual emission until
23229 we have a chance to determine linkage. */
23232 /* Enter the scope of D so that access-checking works correctly. */
23245 }
23249 {
23250 /* Set up the list of local specializations. */
23254 /* Set up context. */
23258 else
23261 /* Some typedefs referenced from within the template code need to be
23262 access checked at template instantiation time, i.e now. These
23263 types were added to the template at parsing time. Let's get those
23264 and perform the access checks then. */
23266 args);
23268 /* Create substitution entries for the parameters. */
23271 /* Substitute into the body of the function. */
23275 else
23276 {
23281 /* Set the current input_location to the end of the function
23282 so that finish_function knows where we are. */
23283 input_location
23286 /* Remember if we saw an infinite loop in the template. */
23287 current_function_infinite_loop
23289 }
23291 /* Finish the function. */
23295 else
23296 {
23299 }
23303 }
23305 /* We're not deferring instantiation any more. */
23310 else
23316 out:
23325 }
23327 /* Run through the list of templates that we wish we could
23328 instantiate, and instantiate any we can. RETRIES is the
23329 number of times we retry pending template instantiation. */
23331 void
23333 {
23337 /* Instantiating templates may trigger vtable generation. This in turn
23338 may require further template instantiations. We place a limit here
23339 to avoid infinite loop. */
23341 {
23345 "template instantiation depth exceeds maximum of %d"
23346 " instantiating %q+D, possibly from virtual table generation"
23350 /* Pretend that we defined it. */
23353 }
23355 do
23356 {
23361 {
23366 {
23368 {
23383 }
23386 }
23387 else
23388 {
23391 {
23392 instantiation
23398 }
23402 }
23405 /* If INSTANTIATION has been instantiated, then we don't
23406 need to consider it again in the future. */
23408 else
23409 {
23412 }
23415 }
23417 }
23421 }
23423 /* Substitute ARGVEC into T, which is a list of initializers for
23424 either base class or a non-static data member. The TREE_PURPOSEs
23425 are DECLs, and the TREE_VALUEs are the initializer values. Used by
23426 instantiate_decl. */
23428 static tree
23430 {
23434 {
23435 tree decl;
23436 tree init;
23442 {
23443 tree expr;
23444 tree arg;
23446 /* Expand the base class expansion type into separate base
23447 classes. */
23449 tf_warning_or_error,
23450 NULL_TREE);
23454 /* We'll be building separate TREE_LISTs of arguments for
23455 each base. */
23461 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
23462 expand each argument in the TREE_VALUE of t. */
23469 /* VOID_TYPE_NODE is used to indicate
23470 value-initialization. */
23471 {
23474 }
23475 else
23476 {
23477 /* Substitute parameter packs into each argument in the
23478 TREE_LIST. */
23481 {
23482 tree expanded_exprs;
23484 /* Expand the argument. */
23486 expanded_exprs
23488 tf_warning_or_error,
23489 NULL_TREE);
23493 /* Prepend each of the expanded expressions to the
23494 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
23496 {
23501 }
23502 }
23505 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
23506 since we built them backwards. */
23508 {
23511 }
23512 }
23513 }
23516 {
23518 {
23522 }
23523 else
23524 {
23525 tree tmp;
23540 /* If we had an initializer but it instantiated to nothing,
23541 value-initialize the object. This will only occur when
23542 the initializer was a pack expansion where the parameter
23543 packs used in that expansion were of length zero. */
23546 }
23549 {
23553 }
23554 }
23555 }
23557 }
23559 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
23561 static void
23563 {
23568 else
23570 }
23572 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
23573 is the instantiation (which should have been created with
23574 start_enum) and ARGS are the template arguments to use. */
23576 static void
23578 {
23579 tree e;
23585 {
23586 tree value;
23587 tree decl;
23590 /* Note that in a template enum, the TREE_VALUE is the
23591 CONST_DECL, not the corresponding INTEGER_CST. */
23596 /* Give this enumeration constant the correct access. */
23599 /* Actually build the enumerator itself. Here we're assuming that
23600 enumerators can't have dependent attributes. */
23603 }
23613 }
23615 /* DECL is a FUNCTION_DECL that is a template specialization. Return
23616 its type -- but without substituting the innermost set of template
23617 arguments. So, innermost set of template parameters will appear in
23618 the type. */
23620 tree
23622 {
23623 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
23625 }
23627 /* Return truthvalue if we're processing a template different from
23628 the last one involved in diagnostics. */
23629 bool
23631 {
23633 }
23635 /* Remember current template involved in diagnostics. */
23636 void
23638 {
23640 }
23644 {
23646 }
23648 /* Return TRUE if current_function_decl is being instantiated, false
23649 otherwise. */
23651 bool
23653 {
23656 }
23658 /* [temp.param] Check that template non-type parm TYPE is of an allowable
23659 type. Return false for ok, true for disallowed. Issue error and
23660 inform messages under control of COMPLAIN. */
23662 static bool
23664 {
23679 /* A bound template template parm could later be instantiated to have a valid
23680 nontype parm type via an alias template. */
23686 {
23689 else
23691 type);
23692 }
23694 }
23696 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
23697 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
23699 static bool
23701 {
23702 tree scope;
23704 /* [temp.dep.type]
23706 A type is dependent if it is:
23708 -- a template parameter. Template template parameters are types
23709 for us (since TYPE_P holds true for them) so we handle
23710 them here. */
23714 /* -- a qualified-id with a nested-name-specifier which contains a
23715 class-name that names a dependent type or whose unqualified-id
23716 names a dependent type. */
23720 /* An alias template specialization can be dependent even if the
23721 resulting type is not. */
23725 /* -- a cv-qualified type where the cv-unqualified type is
23726 dependent.
23727 No code is necessary for this bullet; the code below handles
23728 cv-qualified types, and we don't want to strip aliases with
23729 TYPE_MAIN_VARIANT because of DR 1558. */
23730 /* -- a compound type constructed from any dependent type. */
23740 {
23741 tree arg_type;
23746 arg_type;
23751 /* A value-dependent noexcept-specifier makes the type dependent. */
23754 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
23755 affect overload resolution and treating it as dependent breaks
23756 things. */
23761 }
23762 /* -- an array type constructed from any dependent type or whose
23763 size is specified by a constant expression that is
23764 value-dependent.
23766 We checked for type- and value-dependence of the bounds in
23767 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
23769 {
23774 }
23776 /* -- a template-id in which either the template name is a template
23777 parameter ... */
23780 /* ... or any of the template arguments is a dependent type or
23781 an expression that is type-dependent or value-dependent. */
23783 && (any_dependent_template_arguments_p
23787 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
23788 dependent; if the argument of the `typeof' expression is not
23789 type-dependent, then it should already been have resolved. */
23795 /* A template argument pack is dependent if any of its packed
23796 arguments are. */
23798 {
23804 }
23806 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
23807 be template parameters. */
23814 /* The standard does not specifically mention types that are local
23815 to template functions or local classes, but they should be
23816 considered dependent too. For example:
23818 template <int I> void f() {
23819 enum E { a = I };
23820 S<sizeof (E)> s;
23821 }
23823 The size of `E' cannot be known until the value of `I' has been
23824 determined. Therefore, `E' must be considered dependent. */
23828 /* Don't use type_dependent_expression_p here, as it can lead
23829 to infinite recursion trying to determine whether a lambda
23830 nested in a lambda is dependent (c++/47687). */
23834 && (any_dependent_template_arguments_p
23838 /* Other types are non-dependent. */
23840 }
23842 /* Returns TRUE if TYPE is dependent, in the sense of
23843 [temp.dep.type]. Note that a NULL type is considered dependent. */
23845 bool
23847 {
23848 /* If there are no template parameters in scope, then there can't be
23849 any dependent types. */
23851 {
23852 /* If we are not processing a template, then nobody should be
23853 providing us with a dependent type. */
23857 }
23859 /* If the type is NULL, we have not computed a type for the entity
23860 in question; in that case, the type is dependent. */
23864 /* Erroneous types can be considered non-dependent. */
23868 /* Getting here with global_type_node means we improperly called this
23869 function on the TREE_TYPE of an IDENTIFIER_NODE. */
23872 /* If we have not already computed the appropriate value for TYPE,
23873 do so now. */
23875 {
23878 }
23881 }
23883 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
23884 lookup. In other words, a dependent type that is not the current
23885 instantiation. */
23887 bool
23889 {
23892 }
23894 /* T is a SCOPE_REF; return whether we need to consider it
23895 instantiation-dependent so that we can check access at instantiation
23896 time even though we know which member it resolves to. */
23898 static bool
23900 {
23906 else
23908 }
23910 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
23911 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
23912 expression. */
23914 /* Note that this predicate is not appropriate for general expressions;
23915 only constant expressions (that satisfy potential_constant_expression)
23916 can be tested for value dependence. */
23918 bool
23920 {
23924 /* A type-dependent expression is also value-dependent. */
23929 {
23931 /* A dependent member function of the current instantiation. */
23935 /* A dependent member function of the current instantiation. */
23942 /* A name that has not been looked up -- must be dependent. */
23946 /* A non-type template parm. */
23950 /* A non-type template parm. */
23957 /* A constant with literal type and is initialized
23958 with an expression that is value-dependent.
23960 Note that a non-dependent parenthesized initializer will have
23961 already been replaced with its constant value, so if we see
23962 a TREE_LIST it must be dependent. */
23967 /* cp_finish_decl doesn't fold reference initializers. */
23972 {
23976 }
23985 /* These expressions are value-dependent if the type to which
23986 the cast occurs is dependent or the expression being casted
23987 is value-dependent. */
23988 {
23994 /* A functional cast has a list of operands. */
23997 {
23998 /* If there are no operands, it must be an expression such
23999 as "int()". This should not happen for aggregate types
24000 because it would form non-constant expressions. */
24005 }
24011 }
24016 /* FALLTHRU */
24019 /* A `sizeof' expression is value-dependent if the operand is
24020 type-dependent or is a pack expansion. */
24029 /* An 'encode' expression is value-dependent if the operand is
24030 type-dependent. */
24039 /* All instantiation-dependent expressions should also be considered
24040 value-dependent. */
24048 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
24049 is value-dependent. */
24050 {
24059 }
24062 {
24079 }
24090 {
24094 }
24097 /* Treat all requires-expressions as value-dependent so
24098 we don't try to fold them. */
24105 {
24112 {
24114 /* In a call to a constexpr member function, look through the
24115 implicit ADDR_EXPR on the object argument so that it doesn't
24116 cause the call to be considered value-dependent. We also
24117 look through it in potential_constant_expression. */
24124 }
24126 }
24132 {
24134 tree val;
24141 }
24144 /* Treat a GNU statement expression as dependent to avoid crashing
24145 under instantiate_non_dependent_expr; it can't be constant. */
24149 /* A constant expression is value-dependent if any subexpression is
24150 value-dependent. */
24152 {
24159 {
24163 {
24166 /* In some cases, some of the operands may be missing.
24167 (For example, in the case of PREDECREMENT_EXPR, the
24168 amount to increment by may be missing.) That doesn't
24169 make the expression dependent. */
24172 }
24173 }
24177 }
24179 }
24181 /* The expression is not value-dependent. */
24183 }
24185 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
24186 [temp.dep.expr]. Note that an expression with no type is
24187 considered dependent. Other parts of the compiler arrange for an
24188 expression with type-dependent subexpressions to have no type, so
24189 this function doesn't have to be fully recursive. */
24191 bool
24193 {
24200 /* An unresolved name is always dependent. */
24206 /* A fold expression is type-dependent. */
24213 /* Some expression forms are never type-dependent. */
24227 /* The types of these expressions depends only on the type to which
24228 the cast occurs. */
24237 /* The types of these expressions depends only on the type created
24238 by the expression. */
24241 {
24242 /* For NEW_EXPR tree nodes created inside a template, either
24243 the object type itself or a TREE_LIST may appear as the
24244 operand 1. */
24247 /* This is an array type. We need to check array dimensions
24248 as well. */
24250 || value_dependent_expression_p
24252 else
24254 }
24257 {
24261 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
24262 contains an identifier associated by name lookup with one or more
24263 declarations declared with a dependent type, or...a
24264 nested-name-specifier or qualified-id that names a member of an
24265 unknown specialization. */
24268 }
24278 {
24279 tree elt;
24283 {
24286 }
24288 }
24290 /* A static data member of the current instantiation with incomplete
24291 array type is type-dependent, as the definition and specializations
24292 can have different bounds. */
24299 /* An array of unknown bound depending on a variadic parameter, eg:
24301 template<typename... Args>
24302 void foo (Args... args)
24303 {
24304 int arr[] = { args... };
24305 }
24307 template<int... vals>
24308 void bar ()
24309 {
24310 int arr[] = { vals... };
24311 }
24313 If the array has no length and has an initializer, it must be that
24314 we couldn't determine its length in cp_complete_array_type because
24315 it is dependent. */
24323 /* A function or variable template-id is type-dependent if it has any
24324 dependent template arguments. */
24328 {
24329 /* Consider the innermost template arguments, since those are the ones
24330 that come from the template-id; the template arguments for the
24331 enclosing class do not make it type-dependent unless they are used in
24332 the type of the decl. */
24334 && (any_dependent_template_arguments_p
24337 }
24339 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
24340 type-dependent. Checking this is important for functions with auto return
24341 type, which looks like a dependent type. */
24349 {
24353 }
24355 /* Always dependent, on the number of arguments if nothing else. */
24360 {
24365 {
24371 }
24372 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
24377 {
24382 }
24385 {
24392 }
24402 }
24406 /* Dependent type attributes might not have made it from the decl to
24407 the type yet. */
24413 }
24415 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
24416 type-dependent if the expression refers to a member of the current
24417 instantiation and the type of the referenced member is dependent, or the
24418 class member access expression refers to a member of an unknown
24419 specialization.
24421 This function returns true if the OBJECT in such a class member access
24422 expression is of an unknown specialization. */
24424 bool
24426 {
24427 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
24428 dependent. */
24433 }
24435 /* walk_tree callback function for instantiation_dependent_expression_p,
24436 below. Returns non-zero if a dependent subexpression is found. */
24438 static tree
24441 {
24443 {
24444 /* We don't have to worry about decltype currently because decltype
24445 of an instantiation-dependent expr is a dependent type. This
24446 might change depending on the resolution of DR 1172. */
24449 }
24452 {
24453 /* Don't treat an argument list as dependent just because it has no
24454 TREE_TYPE. */
24462 /* Handle expressions with type operands. */
24467 {
24472 {
24475 else
24476 {
24479 }
24480 }
24482 }
24486 /* In a template, finish_class_member_access_expr creates a
24487 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
24488 type-dependent, so that we can check access control at
24489 instantiation time (PR 42277). See also Core issue 1273. */
24496 else
24499 /* Treat statement-expressions as dependent. */
24503 /* Treat requires-expressions as dependent. */
24508 /* Treat calls to function concepts as dependent. */
24514 /* And variable concepts. */
24521 }
24525 else
24527 }
24529 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
24530 sense defined by the ABI:
24532 "An expression is instantiation-dependent if it is type-dependent
24533 or value-dependent, or it has a subexpression that is type-dependent
24534 or value-dependent."
24536 Except don't actually check value-dependence for unevaluated expressions,
24537 because in sizeof(i) we don't care about the value of i. Checking
24538 type-dependence will in turn check value-dependence of array bounds/template
24539 arguments as needed. */
24541 bool
24543 {
24544 tree result;
24555 }
24557 /* As above, but also check value-dependence of the expression as a whole. */
24559 bool
24561 {
24564 }
24566 /* Like type_dependent_expression_p, but it also works while not processing
24567 a template definition, i.e. during substitution or mangling. */
24569 bool
24571 {
24577 }
24579 /* Returns TRUE if ARGS contains a type-dependent expression. */
24581 bool
24583 {
24585 tree arg;
24588 {
24591 }
24593 }
24595 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24596 expressions) contains any type-dependent expressions. */
24598 bool
24600 {
24606 }
24608 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24609 expressions) contains any value-dependent expressions. */
24611 bool
24613 {
24619 }
24621 /* Returns TRUE if the ARG (a template argument) is dependent. */
24623 bool
24625 {
24629 /* Assume a template argument that was wrongly written by the user
24630 is dependent. This is consistent with what
24631 any_dependent_template_arguments_p [that calls this function]
24632 does. */
24642 {
24645 /* A member template of a dependent class is not necessarily
24646 type-dependent, but it is a dependent template argument because it
24647 will be a member of an unknown specialization to that template. */
24650 }
24652 {
24656 {
24659 }
24662 }
24665 else
24668 }
24670 /* Returns true if ARGS (a collection of template arguments) contains
24671 any types that require structural equality testing. */
24673 bool
24675 {
24685 {
24688 {
24694 {
24695 /* Look inside the argument pack. */
24698 }
24701 {
24714 }
24715 }
24716 }
24719 }
24721 /* Returns true if ARGS (a collection of template arguments) contains
24722 any dependent arguments. */
24724 bool
24726 {
24736 {
24741 }
24744 }
24746 /* Returns TRUE if the template TMPL is type-dependent. */
24748 bool
24750 {
24752 {
24757 }
24759 /* Template template parameters are dependent. */
24763 /* So are names that have not been looked up. */
24767 }
24769 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
24771 bool
24773 {
24776 }
24778 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
24779 are dependent. */
24781 bool
24783 {
24790 {
24812 {
24816 }
24820 {
24824 {
24829 }
24830 }
24831 }
24834 }
24836 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
24837 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
24838 no such TYPE can be found. Note that this function peers inside
24839 uninstantiated templates and therefore should be used only in
24840 extremely limited situations. ONLY_CURRENT_P restricts this
24841 peering to the currently open classes hierarchy (which is required
24842 when comparing types). */
24844 tree
24846 {
24847 tree scope;
24848 tree name;
24849 tree decl;
24851 tree pushed_scope;
24852 tree result;
24857 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
24858 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
24859 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
24860 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
24861 identifier of the TYPENAME_TYPE anymore.
24862 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
24863 TYPENAME_TYPE instead, we avoid messing up with a possible
24864 typedef variant case. */
24867 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
24868 it first before we can figure out what NAME refers to. */
24870 {
24872 /* Given a class template A with a dependent base with nested type C,
24873 typedef typename A::C::C C will land us here, as trying to resolve
24874 the initial A::C leads to the local C typedef, which leads back to
24875 A::C::C. So we break the recursion now. */
24877 else
24879 }
24880 /* If we don't know what SCOPE refers to, then we cannot resolve the
24881 TYPENAME_TYPE. */
24884 /* If this is a typedef, we don't want to look inside (c++/11987). */
24887 /* If SCOPE isn't the template itself, it will not have a valid
24888 TYPE_FIELDS list. */
24890 /* scope is either the template itself or a compatible instantiation
24891 like X<T>, so look up the name in the original template. */
24893 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
24895 /* If scope has no fields, it can't be a current instantiation. Check this
24896 before currently_open_class to avoid infinite recursion (71515). */
24899 /* If the SCOPE is not the current instantiation, there's no reason
24900 to look inside it. */
24903 /* Enter the SCOPE so that name lookup will be resolved as if we
24904 were in the class definition. In particular, SCOPE will no
24905 longer be considered a dependent type. */
24907 /* Look up the declaration. */
24909 tf_warning_or_error);
24913 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
24914 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
24920 {
24924 }
24927 {
24928 /* Obtain the template and the arguments. */
24931 {
24932 /* We get here with a plain identifier because a previous tentative
24933 parse of the nested-name-specifier as part of a ptr-operator saw
24934 ::template X<A>. The use of ::template is necessary in a
24935 ptr-operator, but wrong in a declarator-id.
24937 [temp.names]: In a qualified-id of a declarator-id, the keyword
24938 template shall not appear at the top level. */
24942 }
24944 /* Instantiate the template. */
24950 }
24952 /* Leave the SCOPE. */
24956 /* If we failed to resolve it, return the original typename. */
24960 /* If lookup found a typename type, resolve that too. */
24962 {
24963 /* Ill-formed programs can cause infinite recursion here, so we
24964 must catch that. */
24968 }
24970 /* Qualify the resulting type. */
24976 }
24978 /* EXPR is an expression which is not type-dependent. Return a proxy
24979 for EXPR that can be used to compute the types of larger
24980 expressions containing EXPR. */
24982 tree
24984 {
24985 tree inner_expr;
24987 /* When checking, try to get a constant value for all non-dependent
24988 expressions in order to expose bugs in *_dependent_expression_p
24989 and constexpr. This can affect code generation, see PR70704, so
24990 only do this for -fchecking=2. */
24993 /* Don't do this during nsdmi parsing as it can lead to
24994 unexpected recursive instantiations. */
24996 /* Don't do this during concept expansion either and for
24997 the same reason. */
25001 /* Preserve OVERLOADs; the functions must be available to resolve
25002 types. */
25013 /* There is no need to return a proxy for a variable. */
25016 /* Preserve string constants; conversions from string constants to
25017 "char *" are allowed, even though normally a "const char *"
25018 cannot be used to initialize a "char *". */
25021 /* Preserve void and arithmetic constants, as an optimization -- there is no
25022 reason to create a new node. */
25027 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
25028 There is at least one place where we want to know that a
25029 particular expression is a throw-expression: when checking a ?:
25030 expression, there are special rules if the second or third
25031 argument is a throw-expression. */
25035 /* Don't wrap an initializer list, we need to be able to look inside. */
25039 /* Don't wrap a dummy object, we need to be able to test for it. */
25058 /* If the type is unknown, it can't really be non-dependent */
25061 /* Otherwise, build a NON_DEPENDENT_EXPR. */
25063 }
25065 /* ARGS is a vector of expressions as arguments to a function call.
25066 Replace the arguments with equivalent non-dependent expressions.
25067 This modifies ARGS in place. */
25069 void
25071 {
25073 tree arg;
25076 {
25080 }
25081 }
25083 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
25084 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
25085 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
25087 static tree
25089 {
25103 }
25105 tree
25107 {
25109 }
25111 tree
25113 {
25115 }
25117 /* Return a C++17 deduction placeholder for class template TMPL. */
25119 tree
25121 {
25125 }
25127 /* True iff T is a C++17 class template deduction placeholder. */
25129 bool
25131 {
25133 }
25135 /* Make a "constrained auto" type-specifier. This is an
25136 auto type with constraints that must be associated after
25137 deduction. The constraint is formed from the given
25138 CONC and its optional sequence of arguments, which are
25139 non-null if written as partial-concept-id. */
25141 tree
25143 {
25146 /* Build the constraint. */
25154 /* Our canonical type depends on the constraint. */
25157 /* Attach the constraint to the type declaration. */
25160 }
25162 /* Given type ARG, return std::initializer_list<ARG>. */
25164 static tree
25166 {
25170 {
25174 "deducing from brace-enclosed initializer list"
25178 }
25184 }
25186 /* Replace auto in TYPE with std::initializer_list<auto>. */
25188 static tree
25190 {
25197 }
25199 /* Hash traits for hashing possibly constrained 'auto'
25200 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
25203 {
25206 };
25208 /* Hash the 'auto' T. */
25210 inline hashval_t
25212 {
25214 /* Matching constrained-type-specifiers denote the same template
25215 parameter, so hash the constraint. */
25217 else
25218 /* But unconstrained autos are all separate, so just hash the pointer. */
25220 }
25222 /* Compare two 'auto's. */
25226 {
25233 /* Two unconstrained autos are distinct. */
25238 }
25240 /* for_each_template_parm callback for extract_autos: if t is a (possibly
25241 constrained) auto, add it to the vector. */
25243 static int
25245 {
25248 {
25249 /* All the autos were built with index 0; fix that up now. */
25253 /* If this is a repeated constrained-type-specifier, use the index we
25254 chose before. */
25256 else
25257 {
25258 /* Otherwise this is new, so use the current count. */
25261 }
25263 }
25265 /* Always keep walking. */
25267 }
25269 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
25270 says they can appear anywhere in the type. */
25272 static tree
25274 {
25283 {
25288 }
25291 }
25293 /* The stem for deduction guide names. */
25296 /* Return the name for a deduction guide for class template TMPL. */
25298 tree
25300 {
25311 }
25313 /* True if NAME is the name of a deduction guide. */
25315 bool
25317 {
25321 }
25323 /* True if FN is a deduction guide. */
25325 bool
25327 {
25332 }
25334 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
25336 bool
25338 {
25345 }
25347 /* True if FN is a guide generated from a constructor template. */
25349 bool
25351 {
25359 }
25361 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
25362 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
25363 template parameter types. Note that the handling of template template
25364 parameters relies on current_template_parms being set appropriately for the
25365 new template. */
25367 static tree
25370 {
25373 tree newtype;
25376 {
25383 }
25384 else
25388 tree newdecl
25393 tree newidx;
25396 {
25406 {
25411 // First create a copy (ttargs) of tsubst_args with an
25412 // additional level for the template template parameter's own
25413 // template parameters (ttparms).
25414 tree ttparms = (INNERMOST_TEMPLATE_PARMS
25422 // Substitute ttargs into ttparms to fix references to
25423 // other template parameters.
25425 complain);
25426 // Now substitute again with args based on tparms, to reduce
25427 // the level of the ttparms.
25430 complain);
25431 // Finally, tack the adjusted parms onto tparms.
25433 current_template_parms);
25435 }
25436 }
25437 else
25438 {
25440 tree newconst
25452 }
25455 }
25457 /* Returns a C++17 class deduction guide template based on the constructor
25458 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
25459 guide, or REFERENCE_TYPE for an implicit copy/move guide. */
25461 static tree
25463 {
25467 location_t loc;
25471 {
25475 {
25478 }
25479 else
25489 }
25490 else
25491 {
25494 fn_tmpl
25504 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
25505 fully specialized args for the enclosing class. Strip those off, as
25506 the deduction guide won't have those template parameters. */
25509 /* Discard the 'this' parameter. */
25517 {
25520 /* For a member template constructor, we need to flatten the two
25521 template parameter lists into one, and then adjust the function
25522 signature accordingly. This gets...complicated. */
25525 /* For a member template we should have two levels of parms/args, one
25526 for the class and one for the constructor. We stripped
25527 specialized args for further enclosing classes above. */
25531 /* Template args for translating references to the two-level template
25532 parameters into references to the one-level template parameters we
25533 are creating. */
25538 /* Template parms for the constructor template. */
25541 /* Template parms for the class template. */
25545 /* Template parms for the deduction guide start as a copy of the
25546 template parms for the class. We set current_template_parms for
25547 lookup_template_class_1. */
25553 /* Now we need to rewrite the constructor parms to append them to the
25554 class parms. */
25556 {
25571 }
25573 /* Now we have a final set of template parms to substitute into the
25574 function signature. */
25583 }
25585 }
25588 {
25589 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
25593 }
25597 FUNCTION_DECL,
25614 }
25616 /* Deduce template arguments for the class template placeholder PTYPE for
25617 template TMPL based on the initializer INIT, and return the resulting
25618 type. */
25620 static tree
25622 tsubst_flags_t complain)
25623 {
25625 {
25626 /* We should have handled this in the caller. */
25632 }
25643 {
25646 {
25647 /* As an exception, the first phase in 16.3.1.7 (considering the
25648 initializer list as a single argument) is omitted if the
25649 initializer list consists of a single expression of type cv U,
25650 where U is a specialization of C or a class derived from a
25651 specialization of C. */
25662 }
25665 else
25667 }
25668 else
25679 /* Prune explicit deduction guides in copy-initialization context. */
25681 {
25687 {
25688 /* Found a nonconverting guide, prune the candidates. */
25695 }
25696 }
25701 {
25704 }
25707 // FIXME cache artificial deduction guides
25709 {
25714 else
25718 }
25722 /* If this is list-initialization and the class has a list constructor, first
25723 try deducing from the list as a single argument, as [over.match.list]. */
25727 {
25731 }
25733 {
25739 {
25740 /* That didn't work, now try treating the list as a sequence of
25741 arguments. */
25744 }
25745 }
25747 /* Maybe generate an implicit deduction guide. */
25749 {
25753 /* Generate a copy guide. */
25756 /* Generate a default guide. */
25760 {
25763 }
25764 }
25767 {
25769 " of %qT, as it has no non-explicit deduction guides or "
25772 }
25774 {
25778 }
25781 {
25785 }
25788 {
25798 }
25803 }
25805 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25806 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
25808 tree
25810 {
25812 tf_warning_or_error,
25813 adc_unspecified);
25814 }
25816 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25817 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
25818 The CONTEXT determines the context in which auto deduction is performed
25819 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
25820 OUTER_TARGS are used during template argument deduction
25821 (context == adc_unify) to properly substitute the result, and is ignored
25822 in other contexts.
25824 For partial-concept-ids, extra args may be appended to the list of deduced
25825 template arguments prior to determining constraint satisfaction. */
25827 tree
25831 {
25832 tree targs;
25839 /* Defining a subset of type-dependent expressions that we can deduce
25840 from ahead of time isn't worth the trouble. */
25844 /* C++17 class template argument deduction. */
25848 /* Nothing we can do with this, even in deduction context. */
25851 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
25852 with either a new invented type template parameter U or, if the
25853 initializer is a braced-init-list (8.5.4), with
25854 std::initializer_list<U>. */
25856 {
25861 else
25862 {
25864 {
25868 "for deduction to %<std::initializer_list%>, use copy-"
25870 }
25872 }
25873 }
25884 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
25885 and initializer has array type, deduce cv-qualified array type. */
25887 complain);
25889 {
25898 {
25902 }
25903 }
25904 else
25905 {
25907 tree tparms;
25911 else
25912 {
25916 }
25923 {
25925 /* Try again at instantiation time. */
25929 /* If type is error_mark_node a diagnostic must have been
25930 emitted by now. Also, having a mention to '<type error>'
25931 in the diagnostic is not really useful to the user. */
25932 {
25936 else
25941 }
25943 }
25944 }
25946 /* Check any placeholder constraints against the deduced type. */
25949 {
25950 /* Use the deduced type to check the associated constraints. If we
25951 have a partial-concept-id, rebuild the argument list so that
25952 we check using the extra arguments. */
25956 {
25959 }
25960 else
25963 {
25965 {
25967 {
25985 }
25987 }
25989 }
25990 }
25996 }
25998 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
25999 result. */
26001 tree
26003 {
26005 {
26011 /* In an abbreviated function template we didn't know we were dealing
26012 with a function template when we saw the auto return type, so update
26013 it to have the correct level. */
26015 }
26017 }
26019 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
26020 'decltype(auto)' or a deduced class template. */
26022 bool
26024 {
26030 else
26032 }
26034 /* for_each_template_parm callback for type_uses_auto. */
26036 int
26038 {
26040 }
26042 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
26043 a use of `auto'. Returns NULL_TREE otherwise. */
26045 tree
26047 {
26051 {
26052 /* The Concepts TS allows multiple autos in one type-specifier; just
26053 return the first one we find, do_auto_deduction will collect all of
26054 them. */
26058 else
26060 }
26061 else
26063 }
26065 /* For a given template T, return the vector of typedefs referenced
26066 in T for which access check is needed at T instantiation time.
26067 T is either a FUNCTION_DECL or a RECORD_TYPE.
26068 Those typedefs were added to T by the function
26069 append_type_to_template_for_access_check. */
26073 {
26074 tree ti;
26085 {
26090 }
26093 }
26095 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
26096 tied to T. That list of typedefs will be access checked at
26097 T instantiation time.
26098 T is either a FUNCTION_DECL or a RECORD_TYPE.
26099 TYPE_DECL is a TYPE_DECL node representing a typedef.
26100 SCOPE is the scope through which TYPE_DECL is accessed.
26101 LOCATION is the location of the usage point of TYPE_DECL.
26103 This function is a subroutine of
26104 append_type_to_template_for_access_check. */
26106 static void
26108 tree type_decl,
26109 tree scope,
26110 location_t location)
26111 {
26112 qualified_typedef_usage_t typedef_usage;
26113 tree ti;
26120 && type_decl
26134 }
26136 /* Append TYPE_DECL to the template TEMPL.
26137 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
26138 At TEMPL instanciation time, TYPE_DECL will be checked to see
26139 if it can be accessed through SCOPE.
26140 LOCATION is the location of the usage point of TYPE_DECL.
26142 e.g. consider the following code snippet:
26144 class C
26145 {
26146 typedef int myint;
26147 };
26149 template<class U> struct S
26150 {
26151 C::myint mi; // <-- usage point of the typedef C::myint
26152 };
26154 S<char> s;
26156 At S<char> instantiation time, we need to check the access of C::myint
26157 In other words, we need to check the access of the myint typedef through
26158 the C scope. For that purpose, this function will add the myint typedef
26159 and the scope C through which its being accessed to a list of typedefs
26160 tied to the template S. That list will be walked at template instantiation
26161 time and access check performed on each typedefs it contains.
26162 Note that this particular code snippet should yield an error because
26163 myint is private to C. */
26165 void
26167 tree type_decl,
26168 tree scope,
26169 location_t location)
26170 {
26176 /* Make sure we don't append the type to the template twice. */
26183 }
26185 /* Convert the generic type parameters in PARM that match the types given in the
26186 range [START_IDX, END_IDX) from the current_template_parms into generic type
26187 packs. */
26189 tree
26191 {
26202 {
26203 /* Create a distinct parameter pack type from the current parm and add it
26204 to the replacement args to tsubst below into the generic function
26205 parameter. */
26220 }
26226 /* If there are more levels then build up the replacement with the outer
26227 template parms. */
26231 replacement);
26234 }
26236 /* Entries in the decl_constraint hash table. */
26238 {
26239 tree decl;
26240 tree ci;
26241 };
26243 /* Hashing function and equality for constraint entries. */
26245 {
26247 {
26249 }
26252 {
26254 }
26255 };
26257 /* A mapping from declarations to constraint information. Note that
26258 both templates and their underlying declarations are mapped to the
26259 same constraint information.
26261 FIXME: This is defined in pt.c because garbage collection
26262 code is not being generated for constraint.cc. */
26266 /* Returns the template constraints of declaration T. If T is not
26267 constrained, return NULL_TREE. Note that T must be non-null. */
26269 tree
26271 {
26282 else
26284 }
26286 /* Associate the given constraint information CI with the declaration
26287 T. If T is a template, then the constraints are associated with
26288 its underlying declaration. Don't build associations if CI is
26289 NULL_TREE. */
26291 void
26293 {
26305 }
26307 /* Remove the associated constraints of the declaration T. */
26309 void
26311 {
26320 }
26322 /* Memoized satisfaction results for declarations. This
26323 maps the pair (constraint_info, arguments) to the result computed
26324 by constraints_satisfied_p. */
26327 {
26328 tree ci;
26329 tree args;
26330 tree result;
26331 };
26333 /* Hashing function and equality for constraint entries. */
26336 {
26338 {
26341 }
26344 {
26346 }
26347 };
26349 /* Memoized satisfaction results for concept checks. */
26352 {
26353 tree tmpl;
26354 tree args;
26355 tree result;
26356 };
26358 /* Hashing function and equality for constraint entries. */
26361 {
26363 {
26365 }
26368 {
26373 }
26374 };
26379 /* Search for a memoized satisfaction result. Returns one of the
26380 truth value nodes if previously memoized, or NULL_TREE otherwise. */
26382 tree
26384 {
26389 else
26391 }
26393 /* Memoize the result of a satisfication test. Returns the saved result. */
26395 tree
26397 {
26404 }
26406 /* Search for a memoized satisfaction result for a concept. */
26408 tree
26410 {
26415 else
26417 }
26419 /* Memoize the result of a concept check. Returns the saved result. */
26421 tree
26423 {
26430 }
26434 /* Returns a prior concept specialization. This returns the substituted
26435 and normalized constraints defined by the concept. */
26437 tree
26439 {
26444 else
26446 }
26448 /* Save a concept expansion for later. */
26450 tree
26452 {
26459 }
26461 static hashval_t
26463 {
26472 }
26474 /* Compare the constraints of two subsumption entries. The LEFT1 and
26475 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
26476 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
26478 static bool
26480 {
26488 }
26490 /* Key/value pair for learning and memoizing subsumption results. This
26491 associates a pair of check constraints (including arguments) with
26492 a boolean value indicating the result. */
26495 {
26496 tree t1;
26497 tree t2;
26499 };
26501 /* Hashing function and equality for constraint entries. */
26504 {
26506 {
26508 }
26511 {
26516 }
26517 };
26521 /* Search for a previously cached subsumption result. */
26525 {
26530 else
26532 }
26534 /* Save a subsumption result. */
26536 bool
26538 {
26545 }
26547 /* Set up the hash table for constraint association. */
26549 void
26551 {
26560 }
26562 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
26563 0..N-1. */
26565 void
26567 {
26570 integer_type_node,
26571 NULL_TREE),
26575 }
26577 /* Set up the hash tables for template instantiations. */
26579 void
26581 {
26587 }
26589 /* Print stats about the template hash tables for -fstats. */
26591 void
26593 {
26602 }