| blob | 8bc9c221da71ff328fcd235c593aafeff8498916 |
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 instantiation. */
3292 bool
3294 {
3308 }
3310 /* Return true if PARM is a template template parameter. */
3312 bool
3314 {
3316 }
3318 /* Return true iff PARM is a DECL representing a type template
3319 parameter. */
3321 bool
3323 {
3328 }
3330 /* Return the template parameters of T if T is a
3331 primary template instantiation, NULL otherwise. */
3333 tree
3335 {
3340 parms = INNERMOST_TEMPLATE_PARMS
3344 }
3346 /* Return the template parameters of the LEVELth level from the full list
3347 of template parameters PARMS. */
3349 tree
3351 {
3352 tree p;
3363 }
3365 /* Returns the template arguments of T if T is a template instantiation,
3366 NULL otherwise. */
3368 tree
3370 {
3378 }
3380 /* Return the argument pack elements of T if T is a template argument pack,
3381 NULL otherwise. */
3383 tree
3385 {
3391 }
3393 /* True iff FN is a function representing a built-in variadic parameter
3394 pack. */
3396 bool
3398 {
3408 }
3410 /* True iff CALL is a call to a function representing a built-in variadic
3411 parameter pack. */
3413 static bool
3415 {
3419 }
3421 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3423 static tree
3425 tree in_decl)
3426 {
3432 {
3434 {
3437 }
3442 }
3443 else
3444 {
3448 /* Calculate the largest value of len that won't make the size of the vec
3449 overflow an int. The compiler will exceed resource limits long before
3450 this, but it seems a decent place to diagnose. */
3454 {
3459 }
3467 }
3468 }
3470 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3471 CALL. */
3473 static tree
3475 tree in_decl)
3476 {
3486 }
3488 /* Structure used to track the progress of find_parameter_packs_r. */
3489 struct find_parameter_pack_data
3490 {
3491 /* TREE_LIST that will contain all of the parameter packs found by
3492 the traversal. */
3495 /* Set of AST nodes that have been visited by the traversal. */
3498 /* True iff we're making a type pack expansion. */
3500 };
3502 /* Identifies all of the argument packs that occur in a template
3503 argument and appends them to the TREE_LIST inside DATA, which is a
3504 find_parameter_pack_data structure. This is a subroutine of
3505 make_pack_expansion and uses_parameter_packs. */
3506 static tree
3508 {
3514 /* Handle type aliases/typedefs. */
3516 {
3523 }
3525 /* Identify whether this is a parameter pack or not. */
3527 {
3535 /* FALLTHRU */
3537 /* If the placeholder appears in the decl-specifier-seq of a function
3538 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3539 is a pack expansion, the invented template parameter is a template
3540 parameter pack. */
3550 {
3551 /* We don't want to walk into the type of a PARM_DECL,
3552 because we don't want to see the type parameter pack. */
3555 }
3558 /* Look through a lambda capture proxy to the field pack. */
3561 {
3567 }
3569 {
3571 find_parameter_packs_r,
3574 }
3586 /* Not a parameter pack. */
3588 }
3591 {
3592 /* Add this parameter pack to the list. */
3594 }
3600 /* This switch statement will return immediately if we don't find a
3601 parameter pack. */
3603 {
3608 /* Check the template itself. */
3611 /* Check the template arguments. */
3625 /* Ignore the declaration of a capture proxy for a parameter pack. */
3633 /* Fall through. */
3678 {
3684 }
3687 {
3688 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3689 type_pack_expansion_p to false so that any placeholders
3690 within the expression don't get marked as parameter packs. */
3698 }
3702 }
3705 }
3707 /* Determines if the expression or type T uses any parameter packs. */
3708 bool
3710 {
3719 }
3721 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3722 representation a base-class initializer into a parameter pack
3723 expansion. If all goes well, the resulting node will be an
3724 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3725 respectively. */
3726 tree
3728 {
3729 tree result;
3738 {
3739 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3740 class initializer. In this case, the TREE_PURPOSE will be a
3741 _TYPE node (representing the base class expansion we're
3742 initializing) and the TREE_VALUE will be a TREE_LIST
3743 containing the initialization arguments.
3745 The resulting expansion looks somewhat different from most
3746 expansions. Rather than returning just one _EXPANSION, we
3747 return a TREE_LIST whose TREE_PURPOSE is a
3748 TYPE_PACK_EXPANSION containing the bases that will be
3749 initialized. The TREE_VALUE will be identical to the
3750 original TREE_VALUE, which is a list of arguments that will
3751 be passed to each base. We do not introduce any new pack
3752 expansion nodes into the TREE_VALUE (although it is possible
3753 that some already exist), because the TREE_PURPOSE and
3754 TREE_VALUE all need to be expanded together with the same
3755 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3756 resulting TREE_PURPOSE will mention the parameter packs in
3757 both the bases and the arguments to the bases. */
3758 tree purpose;
3759 tree value;
3762 /* Determine which parameter packs will be used by the base
3763 class expansion. */
3772 {
3775 arg);
3778 }
3781 {
3782 /* Collect the sets of parameter packs used in each of the
3783 initialization arguments. */
3785 {
3786 /* Determine which parameter packs will be expanded in this
3787 argument. */
3790 }
3791 }
3795 /* Create the pack expansion type for the base type. */
3801 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3802 they will rarely be compared to anything. */
3806 }
3811 /* Build the PACK_EXPANSION_* node. */
3812 result = for_types
3817 {
3818 /* Propagate type and const-expression information. */
3821 /* Mark this read now, since the expansion might be length 0. */
3823 }
3824 else
3825 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3826 they will rarely be compared to anything. */
3829 /* Determine which parameter packs will be expanded. */
3836 /* Make sure we found some parameter packs. */
3838 {
3840 {
3843 else
3845 }
3847 }
3853 }
3855 /* Checks T for any "bare" parameter packs, which have not yet been
3856 expanded, and issues an error if any are found. This operation can
3857 only be done on full expressions or types (e.g., an expression
3858 statement, "if" condition, etc.), because we could have expressions like:
3860 foo(f(g(h(args)))...)
3862 where "args" is a parameter pack. check_for_bare_parameter_packs
3863 should not be called for the subexpressions args, h(args),
3864 g(h(args)), or f(g(h(args))), because we would produce erroneous
3865 error messages.
3867 Returns TRUE and emits an error if there were bare parameter packs,
3868 returns FALSE otherwise. */
3869 bool
3871 {
3878 /* A lambda might use a parameter pack from the containing context. */
3892 {
3896 {
3907 else
3912 else
3916 }
3919 }
3922 }
3924 /* Expand any parameter packs that occur in the template arguments in
3925 ARGS. */
3926 tree
3928 {
3937 /* First, determine if we need to expand anything, and the number of
3938 slots we'll need. */
3940 {
3945 {
3949 else
3951 }
3952 else
3953 {
3955 num_result_args++;
3956 }
3957 }
3959 /* If no expansion is necessary, we're done. */
3963 /* Expand arguments. */
3966 non_default_args_count =
3969 {
3972 {
3979 }
3980 else
3981 {
3984 }
3985 }
3989 }
3991 /* Checks if DECL shadows a template parameter.
3993 [temp.local]: A template-parameter shall not be redeclared within its
3994 scope (including nested scopes).
3996 Emits an error and returns TRUE if the DECL shadows a parameter,
3997 returns FALSE otherwise. */
3999 bool
4001 {
4002 tree olddecl;
4004 /* If we're not in a template, we can't possibly shadow a template
4005 parameter. */
4009 /* Figure out what we're shadowing. */
4013 /* If there's no previous binding for this name, we're not shadowing
4014 anything, let alone a template parameter. */
4018 /* If we're not shadowing a template parameter, we're done. Note
4019 that OLDDECL might be an OVERLOAD (or perhaps even an
4020 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4021 node. */
4025 /* We check for decl != olddecl to avoid bogus errors for using a
4026 name inside a class. We check TPFI to avoid duplicate errors for
4027 inline member templates. */
4033 /* Don't complain about the injected class name, as we've already
4034 complained about the class itself. */
4041 else
4046 }
4048 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4049 ORIG_LEVEL, DECL, and TYPE. */
4051 static tree
4055 tree decl,
4056 tree type)
4057 {
4068 }
4070 /* Find the canonical type parameter for the given template type
4071 parameter. Returns the canonical type parameter, which may be TYPE
4072 if no such parameter existed. */
4074 static tree
4076 {
4077 tree list;
4091 else
4092 {
4096 }
4097 }
4099 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4100 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4101 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4102 new one is created. */
4104 static tree
4106 tsubst_flags_t complain)
4107 {
4112 {
4131 /* Template template parameters need this. */
4133 {
4140 }
4141 }
4144 }
4146 /* Process information from new template parameter PARM and append it
4147 to the LIST being built. This new parameter is a non-type
4148 parameter iff IS_NON_TYPE is true. This new parameter is a
4149 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4150 is in PARM_LOC. */
4152 tree
4155 {
4164 {
4168 {
4172 else
4174 }
4177 }
4180 {
4186 {
4187 /* [temp.param]
4189 The top-level cv-qualifiers on the template-parameter are
4190 ignored when determining its type. */
4195 && !is_parameter_pack
4196 /* If we're in a nested template parameter list, the template
4197 template parameter could be a parameter pack. */
4199 {
4200 /* This template parameter is not a parameter pack, but it
4201 should be. Complain about "bare" parameter packs. */
4204 /* Recover by calling this a parameter pack. */
4206 }
4207 }
4209 /* A template parameter is not modifiable. */
4218 processing_template_decl,
4223 }
4224 else
4225 {
4226 tree t;
4230 {
4232 /* This is for distinguishing between real templates and template
4233 template parameters */
4237 }
4238 else
4239 {
4241 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4244 }
4251 processing_template_decl,
4255 }
4259 /* Build requirements for the type/template parameter.
4260 This must be done after SET_DECL_TEMPLATE_PARM_P or
4261 process_template_parm could fail. */
4266 /* Build the parameter node linking the parameter declaration,
4267 its default argument (if any), and its constraints (if any). */
4272 }
4274 /* The end of a template parameter list has been reached. Process the
4275 tree list into a parameter vector, converting each parameter into a more
4276 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4277 as PARM_DECLs. */
4279 tree
4281 {
4286 /* Pop the dummy parameter level and add the real one. */
4289 current_template_parms
4294 {
4298 }
4303 }
4305 // Explicitly indicate the end of the template parameter list. We assume
4306 // that the current template parameters have been constructed and/or
4307 // managed explicitly, as when creating new template template parameters
4308 // from a shorthand constraint.
4309 void
4311 {
4313 }
4315 /* end_template_decl is called after a template declaration is seen. */
4317 void
4319 {
4325 /* This matches the pushlevel in begin_template_parm_list. */
4330 }
4332 /* Takes a TREE_LIST representing a template parameter and convert it
4333 into an argument suitable to be passed to the type substitution
4334 functions. Note that If the TREE_LIST contains an error_mark
4335 node, the returned argument is error_mark_node. */
4337 tree
4339 {
4352 {
4356 {
4357 /* Turn this argument into a TYPE_ARGUMENT_PACK
4358 with a single element, which expands T. */
4367 }
4368 }
4369 else
4370 {
4374 {
4375 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4376 with a single element, which expands T. */
4386 }
4387 else
4389 }
4391 }
4393 /* Given a single level of template parameters (a TREE_VEC), return it
4394 as a set of template arguments. */
4396 static tree
4398 {
4408 }
4410 /* Given a set of template parameters, return them as a set of template
4411 arguments. The template parameters are represented as a TREE_VEC, in
4412 the form documented in cp-tree.h for template arguments. */
4414 static tree
4416 {
4417 tree header;
4422 /* If there is only one level of template parameters, we do not
4423 create a TREE_VEC of TREE_VECs. Instead, we return a single
4424 TREE_VEC containing the arguments. */
4429 {
4434 else
4436 }
4439 }
4441 /* Within the declaration of a template, return the currently active
4442 template parameters as an argument TREE_VEC. */
4444 static tree
4446 {
4448 }
4450 /* Update the declared TYPE by doing any lookups which were thought to be
4451 dependent, but are not now that we know the SCOPE of the declarator. */
4453 tree
4455 {
4466 /* Don't bother building up the args in this case. */
4468 {
4469 /* tsubst in the args corresponding to the template parameters,
4470 including auto if present. Most things will be unchanged, but
4471 make_typename_type and tsubst_qualified_id will resolve
4472 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4475 tree pushed;
4477 {
4481 }
4486 }
4492 {
4495 else
4497 }
4499 }
4501 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4502 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4503 the new template is a member template. */
4505 tree
4507 {
4515 }
4517 struct template_parm_data
4518 {
4519 /* The level of the template parameters we are currently
4520 processing. */
4523 /* The index of the specialization argument we are currently
4524 processing. */
4527 /* An array whose size is the number of template parameters. The
4528 elements are nonzero if the parameter has been used in any one
4529 of the arguments processed so far. */
4532 /* An array whose size is the number of template arguments. The
4533 elements are nonzero if the argument makes use of template
4534 parameters of this level. */
4536 };
4538 /* Subroutine of push_template_decl used to see if each template
4539 parameter in a partial specialization is used in the explicit
4540 argument list. If T is of the LEVEL given in DATA (which is
4541 treated as a template_parm_data*), then DATA->PARMS is marked
4542 appropriately. */
4544 static int
4546 {
4554 {
4557 }
4559 /* In C++17 the type of a non-type argument is a deduced context. */
4564 data,
4565 NULL,
4568 /* Return zero so that for_each_template_parm will continue the
4569 traversal of the tree; we want to mark *every* template parm. */
4571 }
4573 /* Process the partial specialization DECL. */
4575 static tree
4577 {
4584 tree inner_parms;
4585 tree inst;
4595 /* A concept cannot be specialized. */
4597 {
4600 }
4605 /* We check that each of the template parameters given in the
4606 partial specialization is used in the argument list to the
4607 specialization. For example:
4609 template <class T> struct S;
4610 template <class T> struct S<T*>;
4612 The second declaration is OK because `T*' uses the template
4613 parameter T, whereas
4615 template <class T> struct S<int>;
4617 is no good. Even trickier is:
4619 template <class T>
4620 struct S1
4621 {
4622 template <class U>
4623 struct S2;
4624 template <class U>
4625 struct S2<T>;
4626 };
4628 The S2<T> declaration is actually invalid; it is a
4629 full-specialization. Of course,
4631 template <class U>
4632 struct S2<T (*)(U)>;
4634 or some such would have been OK. */
4642 {
4647 NULL,
4649 }
4652 {
4653 /* One of the template parms was not used in a deduced context in the
4654 specialization. */
4656 {
4660 }
4664 }
4669 /* [temp.class.spec]
4671 The argument list of the specialization shall not be identical to
4672 the implicit argument list of the primary template. */
4673 tree main_args
4676 && (!flag_concepts
4679 {
4683 else
4687 }
4689 /* A partial specialization that replaces multiple parameters of the
4690 primary template with a pack expansion is less specialized for those
4691 parameters. */
4693 {
4695 "primary template because it replaces multiple parameters "
4698 /* Avoid crash in process_partial_specialization. */
4700 }
4702 /* If we aren't in a dependent class, we can actually try deduction. */
4704 /* FIXME we should be able to handle a partial specialization of a
4705 partial instantiation, but currently we can't (c++/41727). */
4708 {
4712 maintmpl);
4713 }
4715 /* [temp.class.spec]
4717 A partially specialized non-type argument expression shall not
4718 involve template parameters of the partial specialization except
4719 when the argument expression is a simple identifier.
4721 The type of a template parameter corresponding to a specialized
4722 non-type argument shall not be dependent on a parameter of the
4723 specialization.
4725 Also, we verify that pack expansions only occur at the
4726 end of the argument list. */
4730 {
4737 {
4738 /* Extract the arguments from the argument pack. We'll be
4739 iterating over these in the following loop. */
4742 }
4745 {
4747 /* Get the Jth argument in the parameter pack. */
4751 {
4752 /* Pack expansions must come at the end of the
4753 argument list. */
4756 {
4760 else
4763 }
4764 }
4767 /* We only care about the pattern. */
4773 /* This next two lines are the `argument expression is not just a
4774 simple identifier' condition and also the `specialized
4775 non-type argument' bit. */
4779 {
4783 arg);
4784 else
4785 {
4786 /* Look at the corresponding template parameter,
4787 marking which template parameters its type depends
4788 upon. */
4792 {
4793 /* We haven't yet initialized TPD2. Do so now. */
4795 /* The number of parameters here is the number in the
4796 main template, which, as checked in the assertion
4797 above, is NARGS. */
4801 }
4803 /* Mark the template parameters. But this time, we're
4804 looking for the template parameters of the main
4805 template, not in the specialization. */
4812 NULL,
4816 {
4817 /* The type depended on some template parameters.
4818 If they are fully specialized in the
4819 specialization, that's OK. */
4828 "type %qT of template argument %qE depends "
4830 "type %qT of template argument %qE depends "
4832 type,
4833 arg);
4834 }
4835 }
4836 }
4837 }
4838 }
4840 /* We should only get here once. */
4844 // Build the template decl.
4853 /* Give template template parms a DECL_CONTEXT of the template
4854 for which they are a parameter. */
4856 {
4860 }
4863 /* We didn't register this in check_explicit_specialization so we could
4864 wait until the constraints were set. */
4866 else
4876 {
4882 {
4890 "declaration of %qD ambiguates earlier template "
4894 "partial specialization of %qD after instantiation "
4896 }
4897 }
4900 }
4902 /* PARM is a template parameter of some form; return the corresponding
4903 TEMPLATE_PARM_INDEX. */
4905 static tree
4907 {
4920 }
4922 /* Subroutine of fixed_parameter_pack_p below. Look for any template
4923 parameter packs used by the template parameter PARM. */
4925 static void
4927 {
4928 /* A type parm can't refer to another parm. */
4932 {
4936 }
4943 }
4945 /* PARM is a template parameter pack. Return any parameter packs used in
4946 its type or the type of any of its template parameters. If there are
4947 any such packs, it will be instantiated into a fixed template parameter
4948 list by partial instantiation rather than be fully deduced. */
4950 tree
4952 {
4953 /* This can only be true in a member template. */
4956 /* This can only be true for a parameter pack. */
4959 /* A type parm can't refer to another parm. */
4973 }
4975 /* Check that a template declaration's use of default arguments and
4976 parameter packs is not invalid. Here, PARMS are the template
4977 parameters. IS_PRIMARY is true if DECL is the thing declared by
4978 a primary template. IS_PARTIAL is true if DECL is a partial
4979 specialization.
4981 IS_FRIEND_DECL is nonzero if DECL is a friend function template
4982 declaration (but not a definition); 1 indicates a declaration, 2
4983 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4984 emitted for extraneous default arguments.
4986 Returns TRUE if there were no errors found, FALSE otherwise. */
4988 bool
4991 {
4994 tree parm_level;
4997 /* [temp.param]
4999 A default template-argument shall not be specified in a
5000 function template declaration or a function template definition, nor
5001 in the template-parameter-list of the definition of a member of a
5002 class template. */
5006 /* You can't have a function template declaration in a local
5007 scope, nor you can you define a member of a class template in a
5008 local scope. */
5016 /* A lambda doesn't have an explicit declaration; don't complain
5017 about the parms of the enclosing class. */
5024 /* If this is either a friend defined in the scope of the class
5025 or a member function. */
5031 /* And, if it was a member function, it really was defined in
5032 the scope of the class. */
5035 /* We already checked these parameters when the template was
5036 declared, so there's no need to do it again now. This function
5037 was defined in class scope, but we're processing its body now
5038 that the class is complete. */
5041 /* Core issue 226 (C++0x only): the following only applies to class
5042 templates. */
5045 {
5046 /* [temp.param]
5048 If a template-parameter has a default template-argument, all
5049 subsequent template-parameters shall have a default
5050 template-argument supplied. */
5052 {
5059 {
5069 {
5071 /* For better subsequent error-recovery, we indicate that
5072 there should have been a default argument. */
5075 }
5077 && !is_friend_decl
5078 /* Don't complain about an enclosing partial
5079 specialization. */
5084 /* A fixed parameter pack will be partially
5085 instantiated into a fixed length list. */
5087 {
5088 /* A primary class template can only have one
5089 parameter pack, at the end of the template
5090 parameter list. */
5098 }
5099 }
5100 }
5101 }
5104 || is_partial
5105 || !is_primary
5107 /* For an ordinary class template, default template arguments are
5108 allowed at the innermost level, e.g.:
5109 template <class T = int>
5110 struct S {};
5111 but, in a partial specialization, they're not allowed even
5112 there, as we have in [temp.class.spec]:
5114 The template parameter list of a specialization shall not
5115 contain default template argument values.
5117 So, for a partial specialization, or for a function template
5118 (in C++98/C++03), we look at all of them. */
5119 ;
5120 else
5121 /* But, for a primary class template that is not a partial
5122 specialization we look at all template parameters except the
5123 innermost ones. */
5126 /* Figure out what error message to issue. */
5141 else
5142 /* Per [temp.param]/9, "A default template-argument shall not be
5143 specified in the template-parameter-lists of the definition of
5144 a member of a class template that appears outside of the member's
5145 class.", thus if we aren't handling a member of a class template
5146 there is no need to examine the parameters. */
5150 /* If we're inside a class definition, there's no need to
5151 examine the parameters to the class itself. On the one
5152 hand, they will be checked when the class is defined, and,
5153 on the other, default arguments are valid in things like:
5154 template <class T = double>
5155 struct S { template <class U> void f(U); };
5156 Here the default argument for `S' has no bearing on the
5157 declaration of `f'. */
5159 else
5160 /* Check everything. */
5166 {
5173 {
5178 {
5180 {
5187 }
5189 /* Clear out the default argument so that we are not
5190 confused later. */
5192 }
5193 }
5195 /* At this point, if we're still interested in issuing messages,
5196 they must apply to classes surrounding the object declared. */
5200 }
5203 }
5205 /* Worker for push_template_decl_real, called via
5206 for_each_template_parm. DATA is really an int, indicating the
5207 level of the parameters we are interested in. If T is a template
5208 parameter of that level, return nonzero. */
5210 static int
5212 {
5218 else
5221 }
5223 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5224 DATA is really an int, indicating the innermost outer level of parameters.
5225 If T is a template parameter of that level or further out, return
5226 nonzero. */
5228 static int
5230 {
5236 else
5239 }
5241 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5242 parameters given by current_template_args, or reuses a
5243 previously existing one, if appropriate. Returns the DECL, or an
5244 equivalent one, if it is replaced via a call to duplicate_decls.
5246 If IS_FRIEND is true, DECL is a friend declaration. */
5248 tree
5250 {
5251 tree tmpl;
5252 tree args;
5253 tree info;
5254 tree ctx;
5258 /* True if the template is a member template, in the sense of
5259 [temp.mem]. */
5265 /* See if this is a partial specialization. */
5278 /* For a friend, we want the context of the friend function, not
5279 the type of which it is a friend. */
5283 /* In the case of a virtual function, we want the class in which
5284 it is defined. */
5286 else
5287 /* Otherwise, if we're currently defining some class, the DECL
5288 is assumed to be a member of the class. */
5297 /* See if this is a primary template. */
5300 /* A friend template that specifies a class context, i.e.
5301 template <typename T> friend void A<T>::f();
5302 is not primary. */
5307 else
5311 {
5318 {
5321 }
5323 {
5325 {
5328 }
5330 {
5331 /* [temp.mem]
5333 A destructor shall not be a member template. */
5336 }
5343 {
5344 /* [basic.stc.dynamic.allocation]
5346 An allocation function can be a function
5347 template. ... Template allocation functions shall
5348 have two or more parameters. */
5351 }
5352 }
5355 {
5356 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5359 {
5365 }
5366 }
5369 /* alias-declaration */
5373 else
5374 {
5377 }
5378 }
5380 /* Check to see that the rules regarding the use of default
5381 arguments are not being violated. */
5385 /* Ensure that there are no parameter packs in the type of this
5386 declaration that have not been expanded. */
5388 {
5389 /* Check each of the arguments individually to see if there are
5390 any bare parameter packs. */
5396 {
5399 {
5400 /* This is a PARM_DECL that contains unexpanded parameter
5401 packs. We have already complained about this in the
5402 check_for_bare_parameter_packs call, so just replace
5403 these types with ERROR_MARK_NODE. */
5406 }
5410 }
5412 /* Check for bare parameter packs in the return type and the
5413 exception specifiers. */
5415 /* Errors were already issued, set return type to int
5416 as the frontend doesn't expect error_mark_node as
5417 the return type. */
5421 }
5426 {
5429 }
5442 {
5447 /* If DECL is a TYPE_DECL for a class-template, then there won't
5448 be DECL_LANG_SPECIFIC. The information equivalent to
5449 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5453 {
5454 /* Since a template declaration already existed for this
5455 class-type, we must be redeclaring it here. Make sure
5456 that the redeclaration is valid. */
5458 current_template_parms,
5460 /* We don't need to create a new TEMPLATE_DECL; just use the
5461 one we already had. */
5463 }
5464 else
5465 {
5467 member_template_p);
5472 {
5473 /* A specialization of a member template of a template
5474 class. */
5478 }
5479 }
5480 }
5481 else
5482 {
5488 {
5491 }
5499 {
5500 tree new_tmpl;
5502 /* The declaration is a specialization of a member
5503 template, declared outside the class. Therefore, the
5504 innermost template arguments will be NULL, so we
5505 replace them with the arguments determined by the
5506 earlier call to check_explicit_specialization. */
5509 new_tmpl
5511 member_template_p);
5521 args,
5524 }
5526 /* Make sure the template headers we got make sense. */
5531 {
5536 }
5537 else
5539 {
5544 {
5548 else
5552 /* Avoid crash in import_export_decl. */
5555 }
5560 /* Can happen in erroneous input. */
5562 else
5564 }
5566 /* Check that the parms are used in the appropriate qualifying scopes
5567 in the declarator. */
5571 {
5577 /* Avoid crash in import_export_decl. */
5580 }
5581 }
5586 /* Push template declarations for global functions and types. Note
5587 that we do not try to push a global template friend declared in a
5588 template class; such a thing may well depend on the template
5589 parameters of the class. */
5592 {
5597 /* Hide template friend classes that haven't been declared yet. */
5599 {
5602 }
5603 }
5606 {
5611 /* Give template template parms a DECL_CONTEXT of the template
5612 for which they are a parameter. */
5615 {
5619 }
5625 }
5627 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5628 back to its most general template. If TMPL is a specialization,
5629 ARGS may only have the innermost set of arguments. Add the missing
5630 argument levels if necessary. */
5638 else
5639 {
5644 }
5647 && !is_friend
5650 /* Set DECL_COMDAT on template instantiations; if we force
5651 them to be emitted by explicit instantiation or -frepo,
5652 mark_needed will tell cgraph to do the right thing. */
5656 }
5658 tree
5660 {
5662 }
5664 /* FN is an inheriting constructor that inherits from the constructor
5665 template INHERITED; turn FN into a constructor template with a matching
5666 template header. */
5668 tree
5670 {
5671 tree inner_parms
5674 tree parms
5685 }
5687 /* Called when a class template TYPE is redeclared with the indicated
5688 template PARMS, e.g.:
5690 template <class T> struct S;
5691 template <class T> struct S {}; */
5693 bool
5695 {
5696 tree tmpl;
5697 tree tmpl_parms;
5701 {
5704 }
5708 /* The type is nested in some template class. Nothing to worry
5709 about here; there are no new template parameters for the nested
5710 type. */
5714 {
5716 tmpl);
5718 }
5724 {
5734 }
5737 {
5738 tree tmpl_parm;
5739 tree parm;
5740 tree tmpl_default;
5741 tree parm_default;
5755 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5756 TEMPLATE_DECL. */
5766 {
5770 }
5773 {
5774 /* We have in [temp.param]:
5776 A template-parameter may not be given default arguments
5777 by two different declarations in the same scope. */
5782 }
5785 /* Update the previous template parameters (which are the ones
5786 that will really count) with the new default value. */
5789 /* Update the new parameters, too; they'll be used as the
5790 parameters for any members. */
5793 /* Give each template template parm in this redeclaration a
5794 DECL_CONTEXT of the template for which they are a parameter. */
5796 {
5799 }
5803 }
5805 // Cannot redeclare a class template with a different set of constraints.
5807 {
5812 }
5815 }
5817 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5818 to be used when the caller has already checked
5819 (processing_template_decl
5820 && !instantiation_dependent_expression_p (expr)
5821 && potential_constant_expression (expr))
5822 and cleared processing_template_decl. */
5824 tree
5826 {
5829 complain,
5833 }
5835 /* Simplify EXPR if it is a non-dependent expression. Returns the
5836 (possibly simplified) expression. */
5838 tree
5840 {
5844 /* If we're in a template, but EXPR isn't value dependent, simplify
5845 it. We're supposed to treat:
5847 template <typename T> void f(T[1 + 1]);
5848 template <typename T> void f(T[2]);
5850 as two declarations of the same function, for example. */
5853 {
5854 processing_template_decl_sentinel s;
5856 }
5858 }
5860 tree
5862 {
5864 }
5866 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
5867 an uninstantiated expression. */
5869 tree
5871 {
5875 {
5878 else
5879 {
5880 processing_template_decl_sentinel s;
5882 }
5883 }
5885 }
5887 /* True iff T is a specialization of a variable template. */
5889 bool
5891 {
5896 }
5898 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5899 template declaration, or a TYPE_DECL for an alias declaration. */
5901 bool
5903 {
5911 }
5913 /* Return TRUE iff T is a specialization of an alias template. */
5915 bool
5917 {
5918 /* It's an alias template specialization if it's an alias and its
5919 TYPE_NAME is a specialization of a primary template. */
5925 }
5927 /* An alias template is complex from a SFINAE perspective if a template-id
5928 using that alias can be ill-formed when the expansion is not, as with
5929 the void_t template. We determine this by checking whether the
5930 expansion for the alias template uses all its template parameters. */
5932 struct uses_all_template_parms_data
5933 {
5936 };
5938 static int
5940 {
5948 }
5950 static bool
5952 {
5967 }
5969 /* Return TRUE iff T is a specialization of a complex alias template with
5970 dependent template-arguments. */
5972 bool
5974 {
5987 }
5989 /* Return the number of innermost template parameters in TMPL. */
5991 static int
5993 {
5996 }
5998 /* Return either TMPL or another template that it is equivalent to under DR
5999 1286: An alias that just changes the name of a template is equivalent to
6000 the other template. */
6002 static tree
6004 {
6007 {
6008 /* Determine if the alias is equivalent to an underlying template. */
6020 tree alias_args = INNERMOST_TEMPLATE_ARGS
6025 /* Alias is equivalent. Strip it and repeat. */
6027 }
6030 }
6032 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6033 must be a reference-to-function or a pointer-to-function type, as specified
6034 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6035 and check that the resulting function has external linkage. */
6037 static tree
6039 tsubst_flags_t complain)
6040 {
6043 linkage_kind linkage;
6058 /* [temp.arg.nontype]/1
6060 A template-argument for a non-type, non-template template-parameter
6061 shall be one of:
6062 [...]
6063 -- the address of an object or function with external [C++11: or
6064 internal] linkage. */
6067 {
6069 {
6075 else
6078 }
6080 }
6084 {
6086 {
6091 else
6095 }
6097 }
6099 accept:
6106 }
6108 /* Subroutine of convert_nontype_argument.
6109 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6110 Emit an error otherwise. */
6112 static bool
6114 tsubst_flags_t complain)
6115 {
6132 {
6137 else
6139 }
6141 }
6143 /* Returns TRUE iff the address of OP is value-dependent.
6145 14.6.2.4 [temp.dep.temp]:
6146 A non-integral non-type template-argument is dependent if its type is
6147 dependent or it has either of the following forms
6148 qualified-id
6149 & qualified-id
6150 and contains a nested-name-specifier which specifies a class-name that
6151 names a dependent type.
6153 We generalize this to just say that the address of a member of a
6154 dependent class is value-dependent; the above doesn't cover the
6155 address of a static data member named with an unqualified-id. */
6157 static bool
6159 {
6160 /* We could use get_inner_reference here, but there's no need;
6161 this is only relevant for template non-type arguments, which
6162 can only be expressed as &id-expression. */
6164 {
6168 }
6171 }
6173 /* The next set of functions are used for providing helpful explanatory
6174 diagnostics for failed overload resolution. Their messages should be
6175 indented by two spaces for consistency with the messages in
6176 call.c */
6178 static int
6180 {
6182 }
6184 /* Other failure functions should call this one, to provide a single function
6185 for setting a breakpoint on. */
6187 static int
6189 {
6191 }
6193 static int
6195 {
6200 }
6202 static int
6204 {
6210 }
6212 static int
6214 {
6218 }
6220 static int
6222 {
6225 " template parameter %qD is not a parameter pack, but "
6229 }
6231 static int
6233 {
6236 " template argument %qE does not match "
6240 }
6242 static int
6244 {
6248 }
6250 static int
6252 {
6258 }
6260 static int
6262 {
6264 {
6269 else
6271 " deduced conflicting values for non-type parameter "
6273 }
6275 }
6277 static int
6279 {
6282 " variable-sized array type %qT is not "
6284 arg);
6286 }
6288 static int
6290 {
6294 arg);
6296 }
6298 static int
6300 {
6302 {
6308 else
6313 }
6315 }
6317 static int
6319 {
6321 }
6323 static int
6326 {
6328 }
6330 static int
6333 {
6339 }
6341 static int
6344 {
6347 {
6355 }
6357 }
6359 static int
6361 {
6364 " template parameters of a template template argument are "
6367 }
6369 static int
6371 {
6377 }
6379 static int
6381 {
6386 }
6388 /* Attempt to convert the non-type template parameter EXPR to the
6389 indicated TYPE. If the conversion is successful, return the
6390 converted value. If the conversion is unsuccessful, return
6391 NULL_TREE if we issued an error message, or error_mark_node if we
6392 did not. We issue error messages for out-and-out bad template
6393 parameters, but not simply because the conversion failed, since we
6394 might be just trying to do argument deduction. Both TYPE and EXPR
6395 must be non-dependent.
6397 The conversion follows the special rules described in
6398 [temp.arg.nontype], and it is much more strict than an implicit
6399 conversion.
6401 This function is called twice for each template argument (see
6402 lookup_template_class for a more accurate description of this
6403 problem). This means that we need to handle expressions which
6404 are not valid in a C++ source, but can be created from the
6405 first call (for instance, casts to perform conversions). These
6406 hacks can go away after we fix the double coercion problem. */
6408 static tree
6410 {
6411 tree expr_type;
6415 /* Detect immediately string literals as invalid non-type argument.
6416 This special-case is not needed for correctness (we would easily
6417 catch this later), but only to provide better diagnostic for this
6418 common user mistake. As suggested by DR 100, we do not mention
6419 linkage issues in the diagnostic as this is not the point. */
6420 /* FIXME we're making this OK. */
6422 {
6428 }
6430 /* Add the ADDR_EXPR now for the benefit of
6431 value_dependent_expression_p. */
6434 {
6438 }
6440 /* If we are in a template, EXPR may be non-dependent, but still
6441 have a syntactic, rather than semantic, form. For example, EXPR
6442 might be a SCOPE_REF, rather than the VAR_DECL to which the
6443 SCOPE_REF refers. Preserving the qualifying scope is necessary
6444 so that access checking can be performed when the template is
6445 instantiated -- but here we need the resolved form so that we can
6446 convert the argument. */
6458 /* If the argument is non-dependent, perform any conversions in
6459 non-dependent context as well. */
6467 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6468 to a non-type argument of "nullptr". */
6472 /* In C++11, integral or enumeration non-type template arguments can be
6473 arbitrary constant expressions. Pointer and pointer to
6474 member arguments can be general constant expressions that evaluate
6475 to a null value, but otherwise still need to be of a specific form. */
6477 {
6479 /* A PTRMEM_CST is already constant, and a valid template
6480 argument for a parameter of pointer to member type, we just want
6481 to leave it in that form rather than lower it to a
6485 {
6486 /* C++17: A template-argument for a non-type template-parameter shall
6487 be a converted constant expression (8.20) of the type of the
6488 template-parameter. */
6494 }
6496 {
6501 }
6502 }
6506 else
6509 /* HACK: Due to double coercion, we can get a
6510 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6511 which is the tree that we built on the first call (see
6512 below when coercing to reference to object or to reference to
6513 function). We just strip everything and get to the arg.
6514 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6515 for examples. */
6517 {
6523 {
6524 /* ??? Maybe we could use convert_from_reference here, but we
6525 would need to relax its constraints because the NOP_EXPR
6526 could actually change the type to something more cv-qualified,
6527 and this is not folded by convert_from_reference. */
6532 && (same_type_ignoring_top_level_qualifiers_p
6535 {
6538 }
6539 }
6540 }
6542 /* [temp.arg.nontype]/5, bullet 1
6544 For a non-type template-parameter of integral or enumeration type,
6545 integral promotions (_conv.prom_) and integral conversions
6546 (_conv.integral_) are applied. */
6548 {
6550 {
6555 }
6560 /* Notice that there are constant expressions like '4 % 0' which
6561 do not fold into integer constants. */
6564 {
6566 {
6570 else
6576 /* else cxx_constant_value complained but gave us
6577 a real constant, so go ahead. */
6579 }
6580 else
6582 }
6584 /* Avoid typedef problems. */
6587 }
6588 /* [temp.arg.nontype]/5, bullet 2
6590 For a non-type template-parameter of type pointer to object,
6591 qualification conversions (_conv.qual_) and the array-to-pointer
6592 conversion (_conv.array_) are applied. */
6594 {
6597 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
6598 decay_conversion or an explicit cast. If it's a problematic cast,
6599 we'll complain about it below. */
6601 {
6606 {
6609 }
6610 }
6612 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6614 A template-argument for a non-type, non-template template-parameter
6615 shall be one of: [...]
6617 -- the name of a non-type template-parameter;
6618 -- the address of an object or function with external linkage, [...]
6619 expressed as "& id-expression" where the & is optional if the name
6620 refers to a function or array, or if the corresponding
6621 template-parameter is a reference.
6623 Here, we do not care about functions, as they are invalid anyway
6624 for a parameter of type pointer-to-object. */
6627 /* Non-type template parameters are OK. */
6628 ;
6632 {
6634 {
6637 "because %qD is a variable, not the address of "
6640 }
6642 {
6648 }
6649 /* Other values, like integer constants, might be valid
6650 non-type arguments of some other type. */
6652 }
6653 else
6654 {
6658 {
6663 }
6665 {
6671 }
6674 {
6679 }
6680 /* C++17: For a non-type template-parameter of reference or pointer
6681 type, the value of the constant expression shall not refer to (or
6682 for a pointer type, shall not be the address of):
6683 * a subobject (4.5),
6684 * a temporary object (15.2),
6685 * a string literal (5.13.5),
6686 * the result of a typeid expression (8.2.8), or
6687 * a predefined __func__ variable (11.4.1). */
6689 {
6692 decl);
6694 }
6698 {
6703 }
6705 {
6709 decl);
6711 }
6712 }
6719 }
6720 /* [temp.arg.nontype]/5, bullet 3
6722 For a non-type template-parameter of type reference to object, no
6723 conversions apply. The type referred to by the reference may be more
6724 cv-qualified than the (otherwise identical) type of the
6725 template-argument. The template-parameter is bound directly to the
6726 template-argument, which must be an lvalue. */
6728 {
6730 expr_type))
6734 {
6739 }
6742 {
6747 }
6749 /* [temp.arg.nontype]/1
6751 A template-argument for a non-type, non-template template-parameter
6752 shall be one of: [...]
6754 -- the address of an object or function with external linkage. */
6757 {
6760 {
6763 "because a reference variable does not have a constant "
6766 }
6767 }
6771 /* OK, dependent reference. We don't want to ask whether a DECL is
6773 else
6774 {
6776 {
6782 }
6784 /* DR 1155 allows internal linkage in C++11 and up. */
6787 {
6793 }
6796 }
6800 }
6801 /* [temp.arg.nontype]/5, bullet 4
6803 For a non-type template-parameter of type pointer to function, only
6804 the function-to-pointer conversion (_conv.func_) is applied. If the
6805 template-argument represents a set of overloaded functions (or a
6806 pointer to such), the matching function is selected from the set
6807 (_over.over_). */
6809 {
6810 /* If the argument is a template-id, we might not have enough
6811 context information to decay the pointer. */
6813 {
6817 }
6820 /* Null pointer values are OK in C++11. */
6826 }
6827 /* [temp.arg.nontype]/5, bullet 5
6829 For a non-type template-parameter of type reference to function, no
6830 conversions apply. If the template-argument represents a set of
6831 overloaded functions, the matching function is selected from the set
6832 (_over.over_). */
6834 {
6836 {
6838 {
6843 }
6845 }
6850 }
6851 /* [temp.arg.nontype]/5, bullet 6
6853 For a non-type template-parameter of type pointer to member function,
6854 no conversions apply. If the template-argument represents a set of
6855 overloaded member functions, the matching member function is selected
6856 from the set (_over.over_). */
6858 {
6863 /* [temp.arg.nontype] bullet 1 says the pointer to member
6864 expression must be a pointer-to-member constant. */
6869 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
6870 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
6873 }
6874 /* [temp.arg.nontype]/5, bullet 7
6876 For a non-type template-parameter of type pointer to data member,
6877 qualification conversions (_conv.qual_) are applied. */
6879 {
6880 /* [temp.arg.nontype] bullet 1 says the pointer to member
6881 expression must be a pointer-to-member constant. */
6889 }
6891 {
6893 {
6898 }
6900 }
6901 /* A template non-type parameter must be one of the above. */
6902 else
6905 /* Sanity check: did we actually convert the argument to the
6906 right type? */
6910 }
6912 /* Subroutine of coerce_template_template_parms, which returns 1 if
6913 PARM_PARM and ARG_PARM match using the rule for the template
6914 parameters of template template parameters. Both PARM and ARG are
6915 template parameters; the rest of the arguments are the same as for
6916 coerce_template_template_parms.
6917 */
6918 static int
6920 tree arg,
6921 tsubst_flags_t complain,
6922 tree in_decl,
6923 tree outer_args)
6924 {
6933 {
6935 /* We encounter instantiations of templates like
6936 template <template <template <class> class> class TT>
6937 class C; */
6938 {
6945 }
6946 /* Fall through. */
6951 /* Argument is a parameter pack but parameter is not. */
6956 /* The tsubst call is used to handle cases such as
6958 template <int> class C {};
6959 template <class T, template <T> class TT> class D {};
6960 D<int, C> d;
6962 i.e. the parameter list of TT depends on earlier parameters. */
6964 {
6969 }
6973 /* Argument is a parameter pack but parameter is not. */
6980 }
6983 }
6985 /* Coerce template argument list ARGLIST for use with template
6986 template-parameter TEMPL. */
6988 static tree
6990 tsubst_flags_t complain)
6991 {
6992 /* Consider an example where a template template parameter declared as
6994 template <class T, class U = std::allocator<T> > class TT
6996 The template parameter level of T and U are one level larger than
6997 of TT. To proper process the default argument of U, say when an
6998 instantiation `TT<int>' is seen, we need to build the full
6999 arguments containing {int} as the innermost level. Outer levels,
7000 available when not appearing as default template argument, can be
7001 obtained from the arguments of the enclosing template.
7003 Suppose that TT is later substituted with std::vector. The above
7004 instantiation is `TT<int, std::allocator<T> >' with TT at
7005 level 1, and T at level 2, while the template arguments at level 1
7006 becomes {std::vector} and the inner level 2 is {int}. */
7010 {
7012 /* We want arguments for the partial specialization, not arguments for
7013 the primary template. */
7015 else
7017 }
7019 {
7020 /* This is an argument of the current template, so we haven't set
7021 DECL_CONTEXT yet. */
7022 tree relevant_template_parms;
7024 /* Parameter levels that are greater than the level of the given
7025 template template parm are irrelevant. */
7032 }
7039 complain,
7042 }
7044 /* A cache of template template parameters with match-all default
7045 arguments. */
7047 static void
7049 {
7053 }
7054 static tree
7056 {
7061 }
7063 /* T is a bound template template-parameter. Copy its arguments into default
7064 arguments of the template template-parameter's template parameters. */
7066 static tree
7068 {
7091 {
7094 {
7097 }
7098 }
7102 }
7104 /* ARG is a bound potential template template-argument, and PARGS is a list
7105 of arguments for the corresponding template template-parameter. Adjust
7106 PARGS as appropriate for application to ARG's template, and if ARG is a
7107 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7108 arguments to the template template parameter. */
7110 static tree
7112 {
7116 {
7117 /* When comparing two template template-parameters in partial ordering,
7118 rewrite the one currently being used as an argument to have default
7119 arguments for all parameters. */
7125 }
7126 else
7127 {
7128 tree aparms
7133 }
7136 }
7138 /* Subroutine of unify for the case when PARM is a
7139 BOUND_TEMPLATE_TEMPLATE_PARM. */
7141 static int
7144 {
7148 /* The template template parm might be variadic and the argument
7149 not, so flatten both argument lists. */
7154 {
7155 /* In keeping with P0522R0, adjust P's template arguments
7156 to apply to A's template; then flatten it again. */
7165 /* If the P0522 adjustment eliminated a pack expansion, deduce
7166 empty packs. */
7172 }
7173 else
7174 {
7175 /* Deduce arguments T, i from TT<T> or TT<i>.
7176 We check each element of PARMVEC and ARGVEC individually
7177 rather than the whole TREE_VEC since they can have
7178 different number of elements, which is allowed under N2555. */
7182 /* Check if the parameters end in a pack, making them
7183 variadic. */
7190 /* If the template argument list of P contains a pack
7191 expansion that is not the last template argument, the
7192 entire template argument list is a non-deduced
7193 context. */
7211 DEDUCE_EXACT,
7214 }
7217 }
7219 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7220 template template parameters. Both PARM_PARMS and ARG_PARMS are
7221 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7222 or PARM_DECL.
7224 Consider the example:
7225 template <class T> class A;
7226 template<template <class U> class TT> class B;
7228 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7229 the parameters to A, and OUTER_ARGS contains A. */
7231 static int
7233 tree arg_parms,
7234 tsubst_flags_t complain,
7235 tree in_decl,
7236 tree outer_args)
7237 {
7249 {
7250 /* P0522R0: A template template-parameter P is at least as specialized as
7251 a template template-argument A if, given the following rewrite to two
7252 function templates, the function template corresponding to P is at
7253 least as specialized as the function template corresponding to A
7254 according to the partial ordering rules for function templates
7255 ([temp.func.order]). Given an invented class template X with the
7256 template parameter list of A (including default arguments):
7258 * Each of the two function templates has the same template parameters,
7259 respectively, as P or A.
7261 * Each function template has a single function parameter whose type is
7262 a specialization of X with template arguments corresponding to the
7263 template parameters from the respective function template where, for
7264 each template parameter PP in the template parameter list of the
7265 function template, a corresponding template argument AA is formed. If
7266 PP declares a parameter pack, then AA is the pack expansion
7267 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7269 If the rewrite produces an invalid type, then P is not at least as
7270 specialized as A. */
7272 /* So coerce P's args to apply to A's parms, and then deduce between A's
7273 args and the converted args. If that succeeds, A is at least as
7274 specialized as P, so they match.*/
7281 {
7287 }
7288 }
7290 /* Determine whether we have a parameter pack at the end of the
7291 template template parameter's template parameter list. */
7293 {
7300 {
7314 }
7315 }
7321 /* Check all of the template parameters except the parameter pack at
7322 the end (if any). */
7324 {
7333 outer_args))
7336 }
7339 {
7340 /* Check each of the template parameters in the template
7341 argument against the template parameter pack at the end of
7342 the template template parameter. */
7349 {
7356 outer_args))
7358 }
7359 }
7362 }
7364 /* Verifies that the deduced template arguments (in TARGS) for the
7365 template template parameters (in TPARMS) represent valid bindings,
7366 by comparing the template parameter list of each template argument
7367 to the template parameter list of its corresponding template
7368 template parameter, in accordance with DR150. This
7369 routine can only be called after all template arguments have been
7370 deduced. It will return TRUE if all of the template template
7371 parameter bindings are okay, FALSE otherwise. */
7372 bool
7374 {
7378 /* We're dealing with template parms in this process. */
7384 {
7389 {
7394 {
7395 /* Look inside the argument pack. */
7398 }
7401 {
7405 /* Extract the next argument from the argument
7406 pack. */
7410 /* Look at the pattern of the pack expansion. */
7413 /* Extract the template parameters from the template
7414 argument. */
7420 /* Verify that we can coerce the template template
7421 parameters from the template argument to the template
7422 parameter. This requires an exact match. */
7424 && !coerce_template_template_parms
7426 targ_parms,
7427 tf_none,
7428 tparm,
7429 targs))
7430 {
7433 }
7434 }
7435 }
7436 }
7438 out:
7442 }
7444 /* Since type attributes aren't mangled, we need to strip them from
7445 template type arguments. */
7447 static tree
7449 {
7459 }
7461 /* And from inside dependent non-type arguments like sizeof(Type). */
7463 static tree
7465 {
7475 }
7477 // A template declaration can be substituted for a constrained
7478 // template template parameter only when the argument is more
7479 // constrained than the parameter.
7480 static bool
7482 {
7485 /* For now, allow constrained template template arguments
7486 and unconstrained template template parameters. */
7492 // If the template parameter is constrained, we need to rewrite its
7493 // constraints in terms of the ARG's template parameters. This ensures
7494 // that all of the template parameter types will have the same depth.
7495 //
7496 // Note that this is only valid when coerce_template_template_parm is
7497 // true for the innermost template parameters of PARM and ARG. In other
7498 // words, because coercion is successful, this conversion will be valid.
7500 {
7507 }
7510 }
7512 // Convert a placeholder argument into a binding to the original
7513 // parameter. The original parameter is saved as the TREE_TYPE of
7514 // ARG.
7517 {
7520 }
7522 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
7523 because one of them is dependent. But we need to represent the
7524 conversion for the benefit of cp_tree_equal. */
7526 static tree
7528 {
7529 /* Auto parms get no conversion. */
7532 /* We don't need or want to add this conversion now if we're going to use the
7533 argument for deduction. */
7545 }
7547 /* Convert the indicated template ARG as necessary to match the
7548 indicated template PARM. Returns the converted ARG, or
7549 error_mark_node if the conversion was unsuccessful. Error and
7550 warning messages are issued under control of COMPLAIN. This
7551 conversion is for the Ith parameter in the parameter list. ARGS is
7552 the full set of template arguments deduced so far. */
7554 static tree
7556 tree arg,
7557 tree args,
7558 tsubst_flags_t complain,
7560 tree in_decl)
7561 {
7562 tree orig_arg;
7563 tree val;
7569 /* Trivially convert placeholders. */
7578 {
7579 /* The template argument was the name of some
7580 member function. That's usually
7581 invalid, but static members are OK. In any
7582 case, grab the underlying fields/functions
7583 and issue an error later if required. */
7586 }
7594 /* When determining whether an argument pack expansion is a template,
7595 look at the pattern. */
7599 /* Deal with an injected-class-name used as a template template arg. */
7601 {
7604 {
7614 }
7615 }
7617 is_tmpl_type =
7633 {
7635 {
7639 }
7642 "to refer to a type member of a template parameter, "
7647 typename_type,
7648 complain);
7651 }
7653 {
7655 {
7657 {
7669 else
7672 }
7673 }
7675 }
7677 {
7679 {
7686 else
7689 }
7691 }
7694 /* We already did the appropriate conversion when packing args. */
7697 {
7699 {
7701 /* The number of argument required is not known yet.
7702 Just accept it for now. */
7704 else
7705 {
7707 tree argparm;
7709 /* Strip alias templates that are equivalent to another
7710 template. */
7716 args))
7717 {
7720 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7721 TEMPLATE_DECL. */
7723 {
7728 }
7729 }
7730 else
7731 {
7733 {
7740 }
7743 }
7745 // Check that the constraints are compatible before allowing the
7746 // substitution.
7749 {
7751 {
7757 }
7759 }
7760 }
7761 }
7762 else
7764 /* We only form one instance of each template specialization.
7765 Therefore, if we use a non-canonical variant (i.e., a
7766 typedef), any future messages referring to the type will use
7767 the typedef, which is confusing if those future uses do not
7768 themselves also use the typedef. */
7771 }
7772 else
7773 {
7777 {
7781 }
7782 else
7790 /* We used to call digest_init here. However, digest_init
7791 will report errors, which we don't want when complain
7792 is zero. More importantly, digest_init will try too
7793 hard to convert things: for example, `0' should not be
7794 converted to pointer type at this point according to
7795 the standard. Accepting this is not merely an
7796 extension, since deciding whether or not these
7797 conversions can occur is part of determining which
7798 function template to call, or whether a given explicit
7799 argument specification is valid. */
7801 else
7802 {
7805 }
7815 {
7816 /* Reject template arguments that are references to built-in
7817 functions with no library fallbacks. */
7826 }
7829 {
7830 /* Strip typedefs from the SCOPE_REF. */
7833 complain);
7836 }
7837 }
7840 }
7842 /* Coerces the remaining template arguments in INNER_ARGS (from
7843 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
7844 Returns the coerced argument pack. PARM_IDX is the position of this
7845 parameter in the template parameter list. ARGS is the original
7846 template argument list. */
7847 static tree
7850 tree args,
7851 tree inner_args,
7853 tree new_args,
7855 tree in_decl,
7856 tsubst_flags_t complain)
7857 {
7860 tree packed_args;
7861 tree argument_pack;
7868 {
7869 /* When the template parameter is a non-type template parameter pack
7870 or template template parameter pack whose type or template
7871 parameters use parameter packs, we know exactly how many arguments
7872 we are looking for. Build a vector of the instantiated decls for
7873 these template parameters in PACKED_PARMS. */
7874 /* We can't use make_pack_expansion here because it would interpret a
7875 _DECL as a use rather than a declaration. */
7889 /* If we're doing a partial instantiation of a member template,
7890 verify that all of the types used for the non-type
7891 template parameter pack are, in fact, valid for non-type
7892 template parameters. */
7895 {
7898 {
7902 }
7903 /* We don't know how many args we have yet, just
7904 use the unconverted ones for now. */
7906 }
7909 }
7910 /* Check if we have a placeholder pack, which indicates we're
7911 in the context of a introduction list. In that case we want
7912 to match this pack to the single placeholder. */
7916 {
7919 }
7920 else
7923 /* Convert the remaining arguments, which will be a part of the
7924 parameter pack "parm". */
7927 {
7933 {
7934 /* Once we've packed as many args as we have types, stop. */
7938 /* We don't know how many args we have yet, just
7939 use the unconverted ones for now. */
7941 else
7943 }
7946 {
7949 }
7950 else
7953 in_decl);
7957 }
7961 {
7966 }
7971 else
7972 {
7975 }
7982 }
7984 /* Returns the number of pack expansions in the template argument vector
7985 ARGS. */
7987 static int
7989 {
7994 {
7998 }
8000 }
8002 /* Convert all template arguments to their appropriate types, and
8003 return a vector containing the innermost resulting template
8004 arguments. If any error occurs, return error_mark_node. Error and
8005 warning messages are issued under control of COMPLAIN.
8007 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8008 for arguments not specified in ARGS. Otherwise, if
8009 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
8010 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
8011 USE_DEFAULT_ARGS is false, then all arguments must be specified in
8012 ARGS. */
8014 static tree
8016 tree args,
8017 tree in_decl,
8018 tsubst_flags_t complain,
8021 {
8023 tree orig_inner_args;
8024 tree inner_args;
8025 tree new_args;
8026 tree new_inner_args;
8030 /* When used as a boolean value, indicates whether this is a
8031 variadic template parameter list. Since it's an int, we can also
8032 subtract it from nparms to get the number of non-variadic
8033 parameters. */
8038 /* Likewise for parameters with default arguments. */
8046 /* Determine if there are any parameter packs or default arguments. */
8048 {
8056 }
8059 /* If there are no parameters that follow a parameter pack, we need to
8060 expand any argument packs so that we can deduce a parameter pack from
8061 some non-packed args followed by an argument pack, as in variadic85.C.
8062 If there are such parameters, we need to leave argument packs intact
8063 so the arguments are assigned properly. This can happen when dealing
8064 with a nested class inside a partial specialization of a class
8065 template, as in variadic92.C, or when deducing a template parameter pack
8066 from a sub-declarator, as in variadic114.C. */
8070 /* Count any pack expansion args. */
8076 && require_all_args
8077 && !variadic_args_p
8078 && (!use_default_args
8081 {
8083 {
8085 {
8089 }
8090 else
8097 }
8100 }
8101 /* We can't pass a pack expansion to a non-pack parameter of an alias
8102 template (DR 1430). */
8106 && variadic_args_p
8108 {
8110 {
8112 {
8118 {
8121 "pack expansion argument for non-pack parameter "
8123 else
8125 "pack expansion argument for non-pack parameter "
8129 }
8130 }
8132 found:;
8133 }
8135 }
8137 /* We need to evaluate the template arguments, even though this
8138 template-id may be nested within a "sizeof". */
8147 {
8148 tree arg;
8149 tree parm;
8151 /* Get the Ith template parameter. */
8155 {
8158 }
8160 /* Calculate the next argument. */
8163 else
8168 {
8169 /* Some arguments will be placed in the
8170 template parameter pack PARM. */
8177 {
8178 /* We don't know how many args we have yet, just use the
8179 unconverted (and still packed) ones for now. */
8183 }
8187 /* Store this argument. */
8189 {
8190 lost++;
8191 /* We are done with all of the arguments. */
8193 }
8194 else
8195 {
8198 }
8201 }
8203 {
8205 {
8206 /* "If every valid specialization of a variadic template
8207 requires an empty template parameter pack, the template is
8208 ill-formed, no diagnostic required." So check that the
8209 pattern works with this parameter. */
8214 in_decl);
8216 {
8221 }
8223 /* Recover from missing typename. */
8227 /* We don't know how many args we have yet, just
8228 use the unconverted ones for now. */
8232 }
8233 }
8235 {
8236 /* There must be a default arg in this case. */
8239 /* The position of the first default template argument,
8240 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8241 Record that. */
8245 }
8246 else
8250 {
8253 }
8255 /* This only occurs if there was an error in the template
8256 parameter list itself (which we would already have
8257 reported) that we are trying to recover from, e.g., a class
8258 template with a parameter list such as
8259 template<typename..., typename>. */
8261 else
8267 lost++;
8269 }
8274 {
8276 {
8281 }
8283 }
8293 }
8295 /* Convert all template arguments to their appropriate types, and
8296 return a vector containing the innermost resulting template
8297 arguments. If any error occurs, return error_mark_node. Error and
8298 warning messages are not issued.
8300 Note that no function argument deduction is performed, and default
8301 arguments are used to fill in unspecified arguments. */
8302 tree
8304 {
8306 }
8308 /* Convert all template arguments to their appropriate type, and
8309 instantiate default arguments as needed. This returns a vector
8310 containing the innermost resulting template arguments, or
8311 error_mark_node if unsuccessful. */
8312 tree
8314 tsubst_flags_t complain)
8315 {
8317 }
8319 /* Like coerce_template_parms. If PARMS represents all template
8320 parameters levels, this function returns a vector of vectors
8321 representing all the resulting argument levels. Note that in this
8322 case, only the innermost arguments are coerced because the
8323 outermost ones are supposed to have been coerced already.
8325 Otherwise, if PARMS represents only (the innermost) vector of
8326 parameters, this function returns a vector containing just the
8327 innermost resulting arguments. */
8329 static tree
8331 tree args,
8332 tree in_decl,
8333 tsubst_flags_t complain,
8336 {
8339 tree coerced_args;
8342 {
8344 tree level;
8350 {
8351 tree l;
8355 require_all_args,
8356 use_default_args);
8357 else
8364 }
8365 }
8366 else
8369 require_all_args,
8370 use_default_args);
8372 }
8374 /* Returns 1 if template args OT and NT are equivalent. */
8376 int
8378 {
8387 /* For member templates */
8396 {
8413 }
8417 {
8420 /* Don't treat an alias template specialization with dependent
8421 arguments as equivalent to its underlying type when used as a
8422 template argument; we need them to be distinct so that we
8423 substitute into the specialization arguments at instantiation
8424 time. And aliases can't be equivalent without being ==, so
8425 we don't need to look any deeper.
8427 During partial ordering, however, we need to treat them normally so
8428 that we can order uses of the same alias with different
8429 cv-qualification (79960). */
8433 else
8435 }
8438 else
8439 {
8440 /* Try to treat a template non-type argument that has been converted
8441 to the parameter type as equivalent to one that hasn't yet. */
8454 }
8455 }
8457 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8458 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8459 NEWARG_PTR with the offending arguments if they are non-NULL. */
8461 int
8465 {
8478 {
8483 {
8489 }
8490 }
8492 }
8496 {
8498 }
8500 static void
8502 {
8512 /* We are called both from instantiate_decl, where we've already had a
8513 tinst_level pushed, and instantiate_template, where we haven't.
8514 Compensate. */
8525 else
8534 }
8537 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
8538 ARGLIST. Valid choices for FNS are given in the cp-tree.def
8539 documentation for TEMPLATE_ID_EXPR. */
8541 tree
8543 {
8544 tree type;
8552 {
8555 }
8558 {
8560 unknown_type_node,
8562 arglist);
8564 }
8571 }
8573 /* Within the scope of a template class S<T>, the name S gets bound
8574 (in build_self_reference) to a TYPE_DECL for the class, not a
8575 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
8576 or one of its enclosing classes, and that type is a template,
8577 return the associated TEMPLATE_DECL. Otherwise, the original
8578 DECL is returned.
8580 Also handle the case when DECL is a TREE_LIST of ambiguous
8581 injected-class-names from different bases. */
8583 tree
8585 {
8589 /* DR 176: A lookup that finds an injected-class-name (10.2
8590 [class.member.lookup]) can result in an ambiguity in certain cases
8591 (for example, if it is found in more than one base class). If all of
8592 the injected-class-names that are found refer to specializations of
8593 the same class template, and if the name is followed by a
8594 template-argument-list, the reference refers to the class template
8595 itself and not a specialization thereof, and is not ambiguous. */
8597 {
8600 {
8606 }
8609 else
8611 }
8617 }
8619 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
8620 parameters, find the desired type.
8622 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
8624 IN_DECL, if non-NULL, is the template declaration we are trying to
8625 instantiate.
8627 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
8628 the class we are looking up.
8630 Issue error and warning messages under control of COMPLAIN.
8632 If the template class is really a local class in a template
8633 function, then the FUNCTION_CONTEXT is the function in which it is
8634 being instantiated.
8636 ??? Note that this function is currently called *twice* for each
8637 template-id: the first time from the parser, while creating the
8638 incomplete type (finish_template_type), and the second type during the
8639 real instantiation (instantiate_template_class). This is surely something
8640 that we want to avoid. It also causes some problems with argument
8641 coercion (see convert_nontype_argument for more information on this). */
8643 static tree
8646 {
8648 tree t;
8651 spec_entry elt;
8652 hashval_t hash;
8655 {
8659 else
8660 {
8667 }
8670 }
8672 {
8675 /* If we are declaring a constructor, say A<T>::A<T>, we will get
8676 an implicit typename for the second A. Deal with it. */
8681 {
8684 }
8685 }
8688 {
8691 }
8693 {
8697 }
8699 {
8702 }
8704 /* Issue an error message if we didn't find a template. */
8706 {
8710 }
8713 /* Make sure it's a user visible template, if it was named by
8714 the user. */
8717 {
8719 {
8723 }
8725 }
8729 /* An alias that just changes the name of a template is equivalent to the
8730 other template, so if any of the arguments are pack expansions, strip
8731 the alias to avoid problems with a pack expansion passed to a non-pack
8732 alias template parameter (DR 1430). */
8737 {
8738 tree parm;
8747 }
8748 else
8749 {
8751 tree gen_tmpl;
8752 tree type_decl;
8760 /* An error occurred while building the template TEMPL, and a
8761 diagnostic has most certainly been emitted for that
8762 already. Let's propagate that error. */
8771 {
8772 /* We've been given an incomplete set of template arguments.
8773 For example, given:
8775 template <class T> struct S1 {
8776 template <class U> struct S2 {};
8777 template <class U> struct S2<U*> {};
8778 };
8780 we will be called with an ARGLIST of `U*', but the
8781 TEMPLATE will be `template <class T> template
8782 <class U> struct S1<T>::S2'. We must fill in the missing
8783 arguments. */
8787 }
8789 /* Now we should have enough arguments. */
8792 /* From here on, we're only interested in the most general
8793 template. */
8795 /* Calculate the BOUND_ARGS. These will be the args that are
8796 actually tsubst'd into the definition to create the
8797 instantiation. */
8799 complain,
8804 /* We were unable to bind the arguments. */
8807 /* In the scope of a template class, explicit references to the
8808 template class refer to the type of the template, not any
8809 instantiation of it. For example, in:
8811 template <class T> class C { void f(C<T>); }
8813 the `C<T>' is just the same as `C'. Outside of the
8814 class, however, such a reference is an instantiation. */
8818 {
8823 }
8825 /* If we already have this specialization, return it. */
8835 /* If the the template's constraints are not satisfied,
8836 then we cannot form a valid type.
8838 Note that the check is deferred until after the hash
8839 lookup. This prevents redundant checks on previously
8840 instantiated specializations. */
8842 {
8844 {
8847 }
8849 }
8853 /* If the deduced arguments are invalid, then the binding
8854 failed. */
8858 complain))
8865 {
8870 }
8880 /* Create the type. */
8882 {
8883 /* The user referred to a specialization of an alias
8884 template represented by GEN_TMPL.
8886 [temp.alias]/2 says:
8888 When a template-id refers to the specialization of an
8889 alias template, it is equivalent to the associated
8890 type obtained by substitution of its
8891 template-arguments for the template-parameters in the
8892 type-id of the alias template. */
8895 /* Note that the call above (by indirectly calling
8896 register_specialization in tsubst_decl) registers the
8897 TYPE_DECL representing the specialization of the alias
8898 template. So next time someone substitutes ARGLIST for
8899 the template parms into the alias template (GEN_TMPL),
8900 she'll get that TYPE_DECL back. */
8904 }
8906 {
8908 {
8919 }
8920 else
8921 {
8922 /* We don't want to call start_enum for this type, since
8923 the values for the enumeration constants may involve
8924 template parameters. And, no one should be interested
8925 in the enumeration constants for such a type. */
8928 }
8932 }
8934 {
8940 /* A local class. Make sure the decl gets registered properly. */
8945 /* This instantiation is another name for the primary
8946 template type. Set the TYPE_CANONICAL field
8947 appropriately. */
8950 /* Some of the template arguments require structural
8951 equality testing, so this template class requires
8952 structural equality testing. */
8954 }
8955 else
8958 /* If we called start_enum or pushtag above, this information
8959 will already be set up. */
8961 {
8968 }
8969 else
8973 {
8979 {
8982 }
8983 }
8987 {
8991 {
8992 tree attributes
9000 }
9001 }
9003 /* Let's consider the explicit specialization of a member
9004 of a class template specialization that is implicitly instantiated,
9005 e.g.:
9006 template<class T>
9007 struct S
9008 {
9009 template<class U> struct M {}; //#0
9010 };
9012 template<>
9013 template<>
9014 struct S<int>::M<char> //#1
9015 {
9016 int i;
9017 };
9018 [temp.expl.spec]/4 says this is valid.
9020 In this case, when we write:
9021 S<int>::M<char> m;
9023 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
9024 the one of #0.
9026 When we encounter #1, we want to store the partial instantiation
9027 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
9029 For all cases other than this "explicit specialization of member of a
9030 class template", we just want to store the most general template into
9031 the CLASSTYPE_TI_TEMPLATE of M.
9033 This case of "explicit specialization of member of a class template"
9034 only happens when:
9035 1/ the enclosing class is an instantiation of, and therefore not
9036 the same as, the context of the most general template, and
9037 2/ we aren't looking at the partial instantiation itself, i.e.
9038 the innermost arguments are not the same as the innermost parms of
9039 the most general template.
9041 So it's only when 1/ and 2/ happens that we want to use the partial
9042 instantiation of the member template in lieu of its most general
9043 template. */
9047 /* the enclosing class must be an instantiation... */
9050 {
9054 tree partial_inst_args =
9061 use_partial_inst_tmpl =
9062 /*...and we must not be looking at the partial instantiation
9063 itself. */
9065 partial_inst_args);
9066 }
9069 /* This case is easy; there are no member templates involved. */
9071 else
9072 {
9073 /* This is a full instantiation of a member template. Find
9074 the partial instantiation of which this is an instance. */
9076 /* Temporarily reduce by one the number of levels in the ARGLIST
9077 so as to avoid comparing the last set of arguments. */
9081 /* FOUND is either a proper class type, or an alias
9082 template specialization. In the later case, it's a
9083 TYPE_DECL, resulting from the substituting of arguments
9084 for parameters in the TYPE_DECL of the alias template
9085 done earlier. So be careful while getting the template
9086 of FOUND. */
9088 ? found
9092 }
9094 // Build template info for the new specialization.
9103 /* Note this use of the partial instantiation so we can check it
9104 later in maybe_process_partial_specialization. */
9111 /* Now that the type has been registered on the instantiations
9112 list, we set up the enumerators. Because the enumeration
9113 constants may involve the enumeration type itself, we make
9114 sure to register the type first, and then create the
9115 constants. That way, doing tsubst_expr for the enumeration
9116 constants won't result in recursive calls here; we'll find
9117 the instantiation and exit above. */
9121 /* If the type makes use of template parameters, the
9122 code that generates debugging information will crash. */
9125 /* Possibly limit visibility based on template args. */
9132 }
9133 }
9135 /* Wrapper for lookup_template_class_1. */
9137 tree
9140 {
9141 tree ret;
9147 }
9149 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
9151 tree
9153 {
9154 /* The type of the expression is NULL_TREE since the template-id could refer
9155 to an explicit or partial specialization. */
9158 /* Except that concepts are always bool. */
9161 }
9163 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9165 tree
9167 {
9171 /* We never want to return a VAR_DECL for a variable concept, since they
9172 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
9187 {
9189 {
9192 }
9194 }
9196 /* If a template-id refers to a specialization of a variable
9197 concept, then the expression is true if and only if the
9198 concept's constraints are satisfied by the given template
9199 arguments.
9201 NOTE: This is an extension of Concepts Lite TS that
9202 allows constraints to be used in expressions. */
9204 {
9207 }
9210 }
9212 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
9213 TARGS template args, and instantiate it if it's not dependent. */
9215 tree
9217 tsubst_flags_t complain)
9218 {
9221 {
9224 }
9227 }
9229 \f
9230 struct pair_fn_data
9231 {
9232 tree_fn_t fn;
9233 tree_fn_t any_fn;
9235 /* True when we should also visit template parameters that occur in
9236 non-deduced contexts. */
9239 };
9241 /* Called from for_each_template_parm via walk_tree. */
9243 static tree
9245 {
9252 #define WALK_SUBTREE(NODE) \
9253 do \
9254 { \
9255 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
9256 pfd->include_nondeduced_p, \
9257 pfd->any_fn); \
9258 if (result) goto out; \
9259 } \
9260 while (0)
9270 {
9274 /* Fall through. */
9280 else
9290 /* Since we're not going to walk subtrees, we have to do this
9291 explicitly here. */
9293 /* Fall through. */
9296 /* Check the return type. */
9299 /* Check the parameter types. Since default arguments are not
9300 instantiated until they are needed, the TYPE_ARG_TYPES may
9301 contain expressions that involve template parameters. But,
9302 no-one should be looking at them yet. And, once they're
9303 instantiated, they don't contain template parameters, so
9304 there's no point in looking at them then, either. */
9305 {
9306 tree parm;
9311 /* Since we've already handled the TYPE_ARG_TYPES, we don't
9312 want walk_tree walking into them itself. */
9314 }
9317 {
9321 }
9338 /* Fall through. */
9350 /* Record template parameters such as `T' inside `TT<T>'. */
9352 /* Fall through. */
9364 /* A template template parameter is encountered. */
9368 /* Already substituted template template parameter */
9373 /* A template-id in a TYPENAME_TYPE might be a deduced context after
9374 partial instantiation. */
9386 /* If there's no type, then this thing must be some expression
9387 involving template parameters. */
9409 }
9411 #undef WALK_SUBTREE
9413 /* We didn't find any template parameters we liked. */
9414 out:
9416 }
9418 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9419 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9420 call FN with the parameter and the DATA.
9421 If FN returns nonzero, the iteration is terminated, and
9422 for_each_template_parm returns 1. Otherwise, the iteration
9423 continues. If FN never returns a nonzero value, the value
9424 returned by for_each_template_parm is 0. If FN is NULL, it is
9425 considered to be the function which always returns 1.
9427 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9428 parameters that occur in non-deduced contexts. When false, only
9429 visits those template parameters that can be deduced. */
9431 static tree
9435 tree_fn_t any_fn)
9436 {
9438 tree result;
9440 /* Set up. */
9446 /* Walk the tree. (Conceptually, we would like to walk without
9447 duplicates, but for_each_template_parm_r recursively calls
9448 for_each_template_parm, so we would need to reorganize a fair
9449 bit to use walk_tree_without_duplicates, so we keep our own
9450 visited list.) */
9453 else
9456 for_each_template_parm_r,
9460 /* Clean up. */
9462 {
9465 }
9468 }
9470 /* Returns true if T depends on any template parameter. */
9472 int
9474 {
9504 else
9505 {
9508 }
9513 }
9515 /* Returns true iff current_function_decl is an incompletely instantiated
9516 template. Useful instead of processing_template_decl because the latter
9517 is set to 0 during instantiate_non_dependent_expr. */
9519 bool
9521 {
9530 }
9532 /* Returns true if T depends on any template parameter with level LEVEL. */
9534 bool
9536 {
9539 }
9541 /* Returns true if the signature of DECL depends on any template parameter from
9542 its enclosing class. */
9544 bool
9546 {
9556 template_parm_outer_level,
9566 }
9568 /* Returns TRUE iff INST is an instantiation we don't need to do in an
9569 ill-formed translation unit, i.e. a variable or function that isn't
9570 usable in a constant expression. */
9574 {
9579 }
9581 /* Returns TRUE iff we should refuse to instantiate DECL because it's
9582 neglectable and instantiated from within an erroneous instantiation. */
9584 static bool
9586 {
9597 }
9605 /* We're starting to instantiate D; record the template instantiation context
9606 for diagnostics and to restore it later. */
9608 bool
9610 {
9612 }
9614 /* We're starting to instantiate D; record the template instantiation context
9615 at LOC for diagnostics and to restore it later. */
9617 bool
9619 {
9623 {
9624 /* Tell error.c not to try to instantiate any templates. */
9627 "template instantiation depth exceeds maximum of %d"
9629 max_tinst_depth);
9631 }
9633 /* If the current instantiation caused problems, don't let it instantiate
9634 anything else. Do allow deduction substitution and decls usable in
9635 constant expressions. */
9639 /* When not -quiet, dump template instantiations other than functions, since
9640 announce_function will take care of those. */
9659 }
9661 /* We're done instantiating this template; return to the instantiation
9662 context. */
9664 void
9666 {
9667 /* Restore the filename and line number stashed away when we started
9668 this instantiation. */
9672 }
9674 /* We're instantiating a deferred template; restore the template
9675 instantiation context in which the instantiation was requested, which
9676 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
9678 static tree
9680 {
9692 }
9694 /* Returns the TINST_LEVEL which gives the original instantiation
9695 context. */
9699 {
9705 }
9707 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
9708 vector of template arguments, as for tsubst.
9710 Returns an appropriate tsubst'd friend declaration. */
9712 static tree
9714 {
9715 tree new_friend;
9720 /* This was a friend declared with an explicit template
9721 argument list, e.g.:
9723 friend void f<>(T);
9725 to indicate that f was a template instantiation, not a new
9726 function declaration. Now, we have to figure out what
9727 instantiation of what template. */
9728 {
9730 tree new_args;
9731 tree tmpl;
9734 /* Friend functions are looked up in the containing namespace scope.
9735 We must enter that scope, to avoid finding member functions of the
9736 current class with same name. */
9751 tsk_none);
9753 }
9757 /* The NEW_FRIEND will look like an instantiation, to the
9758 compiler, but is not an instantiation from the point of view of
9759 the language. For example, we might have had:
9761 template <class T> struct S {
9762 template <class U> friend void f(T, U);
9763 };
9765 Then, in S<int>, template <class U> void f(int, U) is not an
9766 instantiation of anything. */
9772 {
9776 }
9778 /* The mangled name for the NEW_FRIEND is incorrect. The function
9779 is not a template instantiation and should not be mangled like
9780 one. Therefore, we forget the mangling here; we'll recompute it
9781 later if we need it. */
9783 {
9786 }
9789 {
9790 tree old_decl;
9791 tree new_friend_template_info;
9792 tree new_friend_result_template_info;
9793 tree ns;
9796 /* We must save some information from NEW_FRIEND before calling
9797 duplicate decls since that function will free NEW_FRIEND if
9798 possible. */
9800 new_friend_is_defn =
9805 {
9806 /* This declaration is a `primary' template. */
9809 new_friend_result_template_info
9811 }
9812 else
9815 /* Inside pushdecl_namespace_level, we will push into the
9816 current namespace. However, the friend function should go
9817 into the namespace of the template. */
9827 {
9828 /* This new friend declaration matched an existing
9829 declaration. For example, given:
9831 template <class T> void f(T);
9832 template <class U> class C {
9833 template <class T> friend void f(T) {}
9834 };
9836 the friend declaration actually provides the definition
9837 of `f', once C has been instantiated for some type. So,
9838 old_decl will be the out-of-class template declaration,
9839 while new_friend is the in-class definition.
9841 But, if `f' was called before this point, the
9842 instantiation of `f' will have DECL_TI_ARGS corresponding
9843 to `T' but not to `U', references to which might appear
9844 in the definition of `f'. Previously, the most general
9845 template for an instantiation of `f' was the out-of-class
9846 version; now it is the in-class version. Therefore, we
9847 run through all specialization of `f', adding to their
9848 DECL_TI_ARGS appropriately. In particular, they need a
9849 new set of outer arguments, corresponding to the
9850 arguments for this class instantiation.
9852 The same situation can arise with something like this:
9854 friend void f(int);
9855 template <class T> class C {
9856 friend void f(T) {}
9857 };
9859 when `C<int>' is instantiated. Now, `f(int)' is defined
9860 in the class. */
9863 /* On the other hand, if the in-class declaration does
9864 *not* provide a definition, then we don't want to alter
9865 existing definitions. We can just leave everything
9866 alone. */
9867 ;
9868 else
9869 {
9873 /* Overwrite whatever template info was there before, if
9874 any, with the new template information pertaining to
9875 the declaration. */
9879 {
9880 /* We should have called reregister_specialization in
9881 duplicate_decls. */
9886 /* Instantiate it if the global has already been used. */
9890 }
9891 else
9892 {
9893 tree t;
9895 /* Indicate that the old function template is a partial
9896 instantiation. */
9904 /* Reassign any specializations already in the hash table
9905 to the new more general template, and add the
9906 additional template args. */
9910 {
9912 spec_entry elt;
9924 register_specialization
9927 }
9929 }
9930 }
9932 /* The information from NEW_FRIEND has been merged into OLD_DECL
9933 by duplicate_decls. */
9935 }
9936 }
9937 else
9938 {
9942 /* In the code
9943 template <class T> class C {
9944 template <class U> friend void C1<U>::f (); // case 1
9945 friend void C2<T>::f (); // case 2
9946 };
9947 we only need to make sure CONTEXT is a complete type for
9948 case 2. To distinguish between the two cases, we note that
9949 CONTEXT of case 1 remains dependent type after tsubst while
9950 this isn't true for case 2. */
9960 {
9962 /* do_friend adds the TEMPLATE_DECL for any member friend
9963 template even if it isn't a member template, i.e.
9964 template <class T> friend A<T>::f();
9965 Look through it in that case. */
9969 /* Check to see that the declaration is really present, and,
9970 possibly obtain an improved declaration. */
9975 }
9976 }
9979 }
9981 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
9982 template arguments, as for tsubst.
9984 Returns an appropriate tsubst'd friend type or error_mark_node on
9985 failure. */
9987 static tree
9989 {
9990 tree friend_type;
9991 tree tmpl;
9992 tree context;
9995 {
9998 }
10003 {
10006 else
10008 }
10010 /* Look for a class template declaration. We look for hidden names
10011 because two friend declarations of the same template are the
10012 same. For example, in:
10014 struct A {
10015 template <typename> friend class F;
10016 };
10017 template <typename> struct B {
10018 template <typename> friend class F;
10019 };
10021 both F templates are the same. */
10025 /* But, if we don't find one, it might be because we're in a
10026 situation like this:
10028 template <class T>
10029 struct S {
10030 template <class U>
10031 friend struct S;
10032 };
10034 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
10035 for `S<int>', not the TEMPLATE_DECL. */
10037 {
10040 }
10043 {
10044 /* The friend template has already been declared. Just
10045 check to see that the declarations match, and install any new
10046 default parameters. We must tsubst the default parameters,
10047 of course. We only need the innermost template parameters
10048 because that is all that redeclare_class_template will look
10049 at. */
10052 {
10053 tree parms;
10054 location_t saved_input_location;
10064 }
10067 }
10068 else
10069 {
10070 /* The friend template has not already been declared. In this
10071 case, the instantiation of the template class will cause the
10072 injection of this template into the global scope. */
10077 /* The new TMPL is not an instantiation of anything, so we
10078 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
10079 the new type because that is supposed to be the corresponding
10080 template decl, i.e., TMPL. */
10087 /* Inject this template into the global scope. */
10089 }
10092 {
10095 else
10097 }
10100 }
10102 /* Returns zero if TYPE cannot be completed later due to circularity.
10103 Otherwise returns one. */
10105 static int
10107 {
10117 else
10119 }
10124 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
10125 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
10127 static tree
10130 {
10139 {
10146 clauses
10150 else
10152 }
10153 /* If the first attribute argument is an identifier, don't
10154 pass it through tsubst. Attributes like mode, format,
10155 cleanup and several target specific attributes expect it
10156 unmodified. */
10158 {
10159 tree chain
10164 }
10166 {
10167 /* An attribute pack expansion. */
10176 {
10180 }
10182 }
10183 else
10190 }
10192 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
10193 unchanged or a new TREE_LIST chain. */
10195 static tree
10198 {
10203 {
10207 }
10211 {
10214 {
10217 {
10219 do
10224 }
10225 }
10227 }
10230 }
10232 /* Apply any attributes which had to be deferred until instantiation
10233 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
10234 ARGS, COMPLAIN, IN_DECL are as tsubst. */
10236 static void
10239 {
10241 tree t;
10248 {
10252 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
10253 to our attributes parameter. */
10255 }
10256 else
10257 {
10259 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
10260 lookup_template_class_1, and should be preserved. */
10264 }
10268 {
10272 }
10276 {
10281 {
10284 {
10288 do
10291 }
10292 else
10294 }
10297 }
10298 }
10300 /* Perform (or defer) access check for typedefs that were referenced
10301 from within the template TMPL code.
10302 This is a subroutine of instantiate_decl and instantiate_class_template.
10303 TMPL is the template to consider and TARGS is the list of arguments of
10304 that template. */
10306 static void
10308 {
10309 location_t saved_location;
10320 {
10332 /* Make access check error messages point to the location
10333 of the use of the typedef. */
10337 tf_warning_or_error);
10338 }
10340 }
10342 static tree
10344 {
10346 tree typedecl;
10347 tree pbinfo;
10348 tree base_list;
10350 tree fn_context;
10359 /* Figure out which template is being instantiated. */
10363 /* Determine what specialization of the original template to
10364 instantiate. */
10367 {
10370 }
10372 {
10373 /* This TYPE is actually an instantiation of a partial
10374 specialization. We replace the innermost set of ARGS with
10375 the arguments appropriate for substitution. For example,
10376 given:
10378 template <class T> struct S {};
10379 template <class T> struct S<T*> {};
10381 and supposing that we are instantiating S<int*>, ARGS will
10382 presently be {int*} -- but we need {int}. */
10385 }
10386 else
10387 {
10390 }
10392 /* If the template we're instantiating is incomplete, then clearly
10393 there's nothing we can do. */
10397 /* If we've recursively instantiated too many templates, stop. */
10401 /* Now we're really doing the instantiation. Mark the type as in
10402 the process of being defined. */
10405 /* We may be in the middle of deferred access check. Disable
10406 it now. */
10413 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10418 else
10419 {
10422 }
10423 /* Use #pragma pack from the template context. */
10429 /* Set the input location to the most specialized template definition.
10430 This is needed if tsubsting causes an error. */
10442 {
10445 /* Adjust visibility for template arguments. */
10447 }
10453 /* We should never instantiate a nested class before its enclosing
10454 class; we need to look up the nested class by name before we can
10455 instantiate it, and that lookup should instantiate the enclosing
10456 class. */
10462 {
10463 tree pbase_binfo;
10464 tree pushed_scope;
10467 /* We must enter the scope containing the type, as that is where
10468 the accessibility of types named in dependent bases are
10469 looked up from. */
10472 /* Substitute into each of the bases to determine the actual
10473 basetypes. */
10475 {
10476 tree base;
10482 {
10483 expanded_bases =
10490 }
10493 {
10495 /* Extract the already-expanded base class. */
10497 else
10498 /* Substitute to figure out the base class. */
10500 NULL_TREE);
10508 }
10509 }
10511 /* The list is now in reverse order; correct that. */
10516 }
10517 /* Now call xref_basetypes to set up all the base-class
10518 information. */
10526 /* Now that our base classes are set up, enter the scope of the
10527 class, so that name lookups into base classes, etc. will work
10528 correctly. This is precisely analogous to what we do in
10529 begin_class_definition when defining an ordinary non-template
10530 class, except we also need to push the enclosing classes. */
10533 /* Now members are processed in the order of declaration. */
10536 {
10540 {
10542 {
10543 /* Build new CLASSTYPE_NESTED_UTDS. */
10545 tree newtag;
10551 /* If the member is a class template, then -- even after
10552 substitution -- there may be dependent types in the
10553 template argument list for the class. We increment
10554 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
10555 that function will assume that no types are dependent
10556 when outside of a template. */
10566 {
10570 /* Unfortunately, lookup_template_class sets
10571 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
10572 instantiation (i.e., for the type of a member
10573 template class nested within a template class.)
10574 This behavior is required for
10575 maybe_process_partial_specialization to work
10576 correctly, but is not accurate in this case;
10577 the TAG is not an instantiation of anything.
10578 (The corresponding TEMPLATE_DECL is an
10579 instantiation, but the TYPE is not.) */
10582 /* Now, we call pushtag to put this NEWTAG into the scope of
10583 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
10584 pushtag calling push_template_decl. We don't have to do
10585 this for enums because it will already have been done in
10586 tsubst_enum. */
10590 }
10591 }
10593 {
10594 tree r;
10603 /* Instantiate members marked with attribute used. */
10609 }
10612 /* A closure type for a lambda in a default argument for a
10613 member template. Ignore it; it will be instantiated with
10615 else
10616 {
10617 /* Build new TYPE_FIELDS. */
10619 {
10620 tree condition;
10623 condition =
10633 }
10635 {
10636 tree r;
10640 /* The file and line for this declaration, to
10641 assist in error message reporting. Since we
10642 called push_tinst_level above, we don't need to
10643 restore these. */
10653 {
10654 /* A capture pack became multiple fields. */
10657 }
10660 {
10664 {
10665 /* In [temp.inst]:
10667 [t]he initialization (and any associated
10668 side-effects) of a static data member does
10669 not occur unless the static data member is
10670 itself used in a way that requires the
10671 definition of the static data member to
10672 exist.
10674 Therefore, we do not substitute into the
10675 initialized for the static data member here. */
10676 finish_static_data_member_decl
10682 /* Instantiate members marked with attribute used. */
10685 }
10687 {
10688 /* Determine whether R has a valid type and can be
10689 completed later. If R is invalid, then its type
10690 is replaced by error_mark_node. */
10696 {
10697 /* If R's type couldn't be completed and
10698 it isn't a flexible array member (whose
10699 type is incomplete by definition) give
10700 an error. */
10703 }
10704 }
10706 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10707 such a thing will already have been added to the field
10708 list by tsubst_enum in finish_member_declaration in the
10709 CLASSTYPE_NESTED_UTDS case above. */
10713 {
10716 }
10717 }
10718 }
10719 }
10720 }
10721 else
10722 {
10725 {
10726 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10732 {
10733 /* template <class T> friend class C; */
10736 }
10738 {
10739 /* template <class T> friend class C::D; */
10745 }
10748 {
10749 /* This could be either
10751 friend class T::C;
10753 when dependent_type_p is false or
10755 template <class U> friend class T::C;
10757 otherwise. */
10758 /* Bump processing_template_decl in case this is something like
10759 template <class T> friend struct A<T>::B. */
10766 }
10770 {
10771 /* friend class C;
10773 where C hasn't been declared yet. Let's lookup name
10774 from namespace scope directly, bypassing any name that
10775 come from dependent base class. */
10778 /* The call to xref_tag_from_type does injection for friend
10779 classes. */
10781 friend_type =
10785 }
10787 /* friend class C<T>; */
10790 /* Otherwise it's
10792 friend class C;
10794 where C is already declared or
10796 friend class C<int>;
10798 We don't have to do anything in these cases. */
10801 /* Trick make_friend_class into realizing that the friend
10802 we're adding is a template, not an ordinary class. It's
10803 important that we use make_friend_class since it will
10804 perform some error-checking and output cross-reference
10805 information. */
10813 }
10814 else
10815 {
10816 /* Build new DECL_FRIENDLIST. */
10817 tree r;
10819 /* The file and line for this declaration, to
10820 assist in error message reporting. Since we
10821 called push_tinst_level above, we don't need to
10822 restore these. */
10826 {
10829 }
10834 {
10837 }
10838 }
10839 }
10840 }
10843 {
10844 /* Restore these before substituting into the lambda capture
10845 initializers. */
10848 }
10851 {
10854 {
10860 {
10861 /* Set function_depth to avoid garbage collection. */
10865 }
10867 /* We need to instantiate the capture list from the template
10868 after we've instantiated the closure members, but before we
10869 consider adding the conversion op. Also keep any captures
10870 that may have been added during instantiation of the op(). */
10872 tree tmpl_cap
10881 }
10882 else
10884 }
10886 /* Set the file and line number information to whatever is given for
10887 the class itself. This puts error messages involving generated
10888 implicit functions at a predictable point, and the same point
10889 that would be used for non-template classes. */
10896 /* We don't instantiate default arguments for member functions. 14.7.1:
10898 The implicit instantiation of a class template specialization causes
10899 the implicit instantiation of the declarations, but not of the
10900 definitions or default arguments, of the class member functions,
10901 member classes, static data members and member templates.... */
10903 /* Some typedefs referenced from within the template code need to be access
10904 checked at template instantiation time, i.e now. These types were
10905 added to the template at parsing time. Let's get those and perform
10906 the access checks then. */
10916 /* The vtable for a template class can be emitted in any translation
10917 unit in which the class is instantiated. When there is no key
10918 method, however, finish_struct_1 will already have added TYPE to
10919 the keyed_classes. */
10924 }
10926 /* Wrapper for instantiate_class_template_1. */
10928 tree
10930 {
10931 tree ret;
10936 }
10938 static tree
10940 {
10941 tree r;
10947 else
10948 {
10955 }
10957 }
10959 /* Given a function parameter pack TMPL_PARM and some function parameters
10960 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
10961 and set *SPEC_P to point at the next point in the list. */
10963 tree
10965 {
10966 /* Collect all of the extra "packed" parameters into an
10967 argument pack. */
10968 tree parmvec;
10978 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
10984 /* Build the argument packs. */
10989 }
10991 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
10992 NONTYPE_ARGUMENT_PACK. */
10994 static tree
10996 {
10998 }
11000 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
11001 pack expansion with no extra args, 2 if it has extra args, or 0
11002 if it is not a pack expansion. */
11004 static int
11006 {
11012 /* A decl pack is itself an expansion. */
11019 }
11022 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
11024 static tree
11026 {
11033 }
11035 /* This is a subroutine of tsubst_pack_expansion.
11037 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
11038 mechanism to store the (non complete list of) arguments of the
11039 substitution and return a non substituted pack expansion, in order
11040 to wait for when we have enough arguments to really perform the
11041 substitution. */
11043 static bool
11047 {
11048 /* If one pack has an expansion and another pack has a normal
11049 argument or if one pack has an empty argument and an another
11050 one hasn't then tsubst_pack_expansion cannot perform the
11051 substitution and need to fall back on the
11052 PACK_EXPANSION_EXTRA mechanism. */
11060 {
11063 parm_pack;
11065 {
11070 /* We can't substitute a pack expansion with extra args into
11071 our pattern. */
11075 else
11077 }
11081 }
11083 }
11085 /* [temp.variadic]/6 says that:
11087 The instantiation of a pack expansion [...]
11088 produces a list E1,E2, ..., En, where N is the number of elements
11089 in the pack expansion parameters.
11091 This subroutine of tsubst_pack_expansion produces one of these Ei.
11093 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
11094 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
11095 PATTERN, and each TREE_VALUE is its corresponding argument pack.
11096 INDEX is the index 'i' of the element Ei to produce. ARGS,
11097 COMPLAIN, and IN_DECL are the same parameters as for the
11098 tsubst_pack_expansion function.
11100 The function returns the resulting Ei upon successful completion,
11101 or error_mark_node.
11103 Note that this function possibly modifies the ARGS parameter, so
11104 it's the responsibility of the caller to restore it. */
11106 static tree
11108 tree parm_packs,
11110 tree args /* This parm gets
11112 tsubst_flags_t complain,
11113 tree in_decl)
11114 {
11115 tree t;
11118 /* For each parameter pack, change the substitution of the parameter
11119 pack to the ith argument in its argument pack, then expand the
11120 pattern. */
11122 {
11127 ith_elem_is_expansion |=
11130 /* Select the Ith argument from the pack. */
11133 {
11135 {
11140 }
11141 else
11143 }
11144 else
11145 {
11150 {
11152 /* Update the corresponding argument. */
11154 }
11155 else
11156 /* Re-use the ARGUMENT_PACK_SELECT. */
11158 }
11160 }
11162 /* Substitute into the PATTERN with the (possibly altered)
11163 arguments. */
11165 /* Expanding a fixed parameter pack from
11166 coerce_template_parameter_pack. */
11171 {
11174 else
11177 }
11181 else
11184 /* If the Ith argument pack element is a pack expansion, then
11185 the Ith element resulting from the substituting is going to
11186 be a pack expansion as well. */
11191 }
11193 /* When the unexpanded parameter pack in a fold expression expands to an empty
11194 sequence, the value of the expression is as follows; the program is
11195 ill-formed if the operator is not listed in this table.
11197 && true
11198 || false
11199 , void() */
11201 tree
11203 {
11207 {
11216 }
11222 }
11224 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11225 form an expression that combines the two terms using the
11226 operator of T. */
11228 static tree
11230 {
11234 // Handle compound assignment operators.
11239 {
11249 complain);
11250 }
11251 }
11253 /* Substitute ARGS into the pack of a fold expression T. */
11257 {
11259 }
11261 /* Substitute ARGS into the pack of a fold expression T. */
11265 {
11267 }
11269 /* Expand a PACK of arguments into a grouped as left fold.
11270 Given a pack containing elements A0, A1, ..., An and an
11271 operator @, this builds the expression:
11273 ((A0 @ A1) @ A2) ... @ An
11275 Note that PACK must not be empty.
11277 The operator is defined by the original fold expression T. */
11279 static tree
11281 {
11284 {
11287 }
11289 }
11291 /* Substitute into a unary left fold expression. */
11293 static tree
11295 tree in_decl)
11296 {
11301 {
11305 }
11308 else
11310 }
11312 /* Substitute into a binary left fold expression.
11314 Do ths by building a single (non-empty) vector of argumnts and
11315 building the expression from those elements. */
11317 static tree
11319 tree in_decl)
11320 {
11329 {
11334 }
11342 }
11344 /* Expand a PACK of arguments into a grouped as right fold.
11345 Given a pack containing elementns A0, A1, ..., and an
11346 operator @, this builds the expression:
11348 A0@ ... (An-2 @ (An-1 @ An))
11350 Note that PACK must not be empty.
11352 The operator is defined by the original fold expression T. */
11354 tree
11356 {
11357 // Build the expression.
11361 {
11364 }
11366 }
11368 /* Substitute into a unary right fold expression. */
11370 static tree
11372 tree in_decl)
11373 {
11378 {
11382 }
11385 else
11387 }
11389 /* Substitute into a binary right fold expression.
11391 Do ths by building a single (non-empty) vector of arguments and
11392 building the expression from those elements. */
11394 static tree
11396 tree in_decl)
11397 {
11406 {
11411 }
11420 }
11423 /* Substitute ARGS into T, which is an pack expansion
11424 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
11425 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
11426 (if only a partial substitution could be performed) or
11427 ERROR_MARK_NODE if there was an error. */
11428 tree
11430 tree in_decl)
11431 {
11432 tree pattern;
11436 tree result;
11444 /* Add in any args remembered from an earlier partial instantiation. */
11449 /* Determine the argument packs that will instantiate the parameter
11450 packs used in the expansion expression. While we're at it,
11451 compute the number of arguments to be expanded and make sure it
11452 is consistent. */
11455 {
11462 {
11467 else
11470 }
11472 {
11473 /* ??? Support use in other patterns. */
11477 }
11479 {
11480 /* We know we have correct local_specializations if this
11481 expansion is at function scope, or if we're dealing with a
11482 local parameter in a requires expression; for the latter,
11483 tsubst_requires_expr set it up appropriately. */
11486 else
11487 /* We can't rely on local_specializations for a parameter
11488 name used later in a function declaration (such as in a
11489 late-specified return type). Even if it exists, it might
11490 have the wrong value for a recursive call. */
11494 {
11495 /* This parameter pack was used in an unevaluated context. Just
11496 make a dummy decl, since it's only used for its type. */
11499 /* Partial instantiation of the parm_pack, we can't build
11500 up an argument pack yet. */
11502 else
11504 }
11505 }
11508 else
11509 {
11515 }
11522 /* This can only happen if we forget to expand an argument
11523 pack somewhere else. Just return an error, silently. */
11524 {
11528 }
11531 {
11535 /* Don't bother trying to do a partial substitution with
11536 incomplete packs; we'll try again after deduction. */
11543 {
11548 pattern);
11549 else
11551 pattern);
11553 }
11555 /* Keep track of the parameter packs and their corresponding
11556 argument packs. */
11559 }
11560 else
11561 {
11562 /* We can't substitute for this parameter pack. We use a flag as
11563 well as the missing_level counter because function parameter
11564 packs don't have a level. */
11567 }
11568 }
11570 /* If the expansion is just T..., return the matching argument pack, unless
11571 we need to call convert_from_reference on all the elements. This is an
11572 important optimization; see c++/68422. */
11575 {
11577 /* Types need no adjustment, nor does sizeof..., and if we still have
11578 some pack expansion args we won't do anything yet. */
11583 /* Also optimize expression pack expansions if we can tell that the
11584 elements won't have reference type. */
11590 /* Otherwise use the normal path so we get convert_from_reference. */
11591 }
11593 /* We cannot expand this expansion expression, because we don't have
11594 all of the argument packs we need. */
11596 {
11597 /* We got some full packs, but we can't substitute them in until we
11598 have values for all the packs. So remember these until then. */
11603 }
11605 {
11606 /* There were no real arguments, we're just replacing a parameter
11607 pack with another version of itself. Substitute into the
11608 pattern and return a PACK_EXPANSION_*. The caller will need to
11609 deal with that. */
11613 else
11617 }
11622 {
11623 /* We're in a late-specified return type, so create our own local
11624 specializations map; the current map is either NULL or (in the
11625 case of recursive unification) might have bindings that we don't
11626 want to use or alter. */
11629 }
11631 /* For each argument in each argument pack, substitute into the
11632 pattern. */
11636 {
11638 i,
11640 in_decl);
11643 {
11646 }
11647 }
11649 /* Update ARGS to restore the substitution from parameter packs to
11650 their argument packs. */
11652 {
11658 else
11659 {
11667 /* Update the corresponding argument. */
11671 else
11673 }
11674 }
11677 {
11680 }
11682 /* If the dependent pack arguments were such that we end up with only a
11683 single pack expansion again, there's no need to keep it in a TREE_VEC. */
11689 }
11691 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
11692 TMPL. We do this using DECL_PARM_INDEX, which should work even with
11693 parameter packs; all parms generated from a function parameter pack will
11694 have the same DECL_PARM_INDEX. */
11696 tree
11698 {
11700 tree patparm;
11703 {
11709 }
11710 else
11711 {
11716 }
11719 }
11721 /* Make an argument pack out of the TREE_VEC VEC. */
11723 static tree
11725 {
11726 tree pack;
11730 else
11731 {
11734 }
11737 }
11739 /* Return an exact copy of template args T that can be modified
11740 independently. */
11742 static tree
11744 {
11752 {
11757 }
11763 }
11765 /* Substitute ARGS into the vector or list of template arguments T. */
11767 static tree
11769 {
11781 {
11783 tree new_arg;
11788 {
11789 /* Substitute into an expansion expression. */
11793 /* Add to the expanded length adjustment the number of
11794 expanded arguments. We subtract one from this
11795 measurement, because the argument pack expression
11796 itself is already counted as 1 in
11797 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
11798 the argument pack is empty. */
11800 }
11802 {
11803 /* Substitute into each of the arguments. */
11812 else
11817 }
11818 else
11827 }
11832 /* Make space for the expanded arguments coming from template
11833 argument packs. */
11835 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
11836 arguments for a member template.
11837 In that case each TREE_VEC in ORIG_T represents a level of template
11838 arguments, and ORIG_T won't carry any non defaulted argument count.
11839 It will rather be the nested TREE_VECs that will carry one.
11840 In other words, ORIG_T carries a non defaulted argument count only
11841 if it doesn't contain any nested TREE_VEC. */
11843 {
11847 }
11849 {
11853 {
11856 /* Now expand the template argument pack "in place". */
11859 }
11860 else
11861 {
11863 out++;
11864 }
11865 }
11868 }
11870 /* Substitute ARGS into one level PARMS of template parameters. */
11872 static tree
11874 {
11881 {
11889 }
11892 }
11894 /* Return the result of substituting ARGS into the template parameters
11895 given by PARMS. If there are m levels of ARGS and m + n levels of
11896 PARMS, then the result will contain n levels of PARMS. For
11897 example, if PARMS is `template <class T> template <class U>
11898 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
11899 result will be `template <int*, double, class V>'. */
11901 static tree
11903 {
11907 /* When substituting into a template, we must set
11908 PROCESSING_TEMPLATE_DECL as the template parameters may be
11909 dependent if they are based on one-another, and the dependency
11910 predicates are short-circuit outside of templates. */
11917 {
11924 }
11929 }
11931 /* Return the result of substituting ARGS into one template parameter
11932 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
11933 parameter and which TREE_PURPOSE is the default argument of the
11934 template parameter. */
11936 static tree
11938 {
11959 }
11961 /* Substitute the ARGS into the indicated aggregate (or enumeration)
11962 type T. If T is not an aggregate or enumeration type, it is
11963 handled as if by tsubst. IN_DECL is as for tsubst. If
11964 ENTERING_SCOPE is nonzero, T is the context for a template which
11965 we are presently tsubst'ing. Return the substituted value. */
11967 static tree
11969 tree args,
11970 tsubst_flags_t complain,
11971 tree in_decl,
11973 {
11978 {
11983 /* Fall through. */
11987 {
11988 tree argvec;
11989 tree context;
11990 tree r;
11994 /* In "sizeof(X<I>)" we need to evaluate "I". */
12000 /* First, determine the context for the type we are looking
12001 up. */
12004 {
12007 /* If context is a nested class inside a class template,
12008 it may still need to be instantiated (c++/33959). */
12010 }
12012 /* Then, figure out what arguments are appropriate for the
12013 type we are trying to find. For example, given:
12015 template <class T> struct S;
12016 template <class T, class U> void f(T, U) { S<U> su; }
12018 and supposing that we are instantiating f<int, double>,
12019 then our ARGS will be {int, double}, but, when looking up
12020 S we only want {double}. */
12025 else
12026 {
12030 }
12036 }
12037 else
12038 /* This is not a template type, so there's nothing to do. */
12043 }
12044 }
12048 /* Substitute into the default argument ARG (a default argument for
12049 FN), which has the indicated TYPE. */
12051 tree
12053 tsubst_flags_t complain)
12054 {
12059 /* This can happen in invalid code. */
12074 /* This default argument came from a template. Instantiate the
12075 default argument here, not in tsubst. In the case of
12076 something like:
12078 template <class T>
12079 struct S {
12080 static T t();
12081 void f(T = t());
12082 };
12084 we must be careful to do name lookup in the scope of S<T>,
12085 rather than in the current class. */
12087 /* The "this" pointer is not valid in a default argument. */
12089 {
12094 }
12099 /* The default argument expression may cause implicitly defined
12100 member functions to be synthesized, which will result in garbage
12101 collection. We must treat this situation as if we were within
12102 the body of function so as to avoid collecting live data on the
12103 stack. */
12113 /* Restore the "this" pointer. */
12115 {
12118 }
12125 /* Make sure the default argument is reasonable. */
12131 {
12135 }
12138 }
12140 /* Substitute into all the default arguments for FN. */
12142 static void
12144 {
12145 tree arg;
12146 tree tmpl_args;
12150 /* If this function is not yet instantiated, we certainly don't need
12151 its default arguments. */
12154 /* Don't do this again for clones. */
12160 arg;
12166 complain);
12167 }
12169 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
12171 static tree
12173 tree lambda_fntype)
12174 {
12179 /* Nobody should be tsubst'ing into non-template functions. */
12183 {
12184 /* If T is not dependent, just return it. */
12188 /* Calculate the most general template of which R is a
12189 specialization, and the complete set of arguments used to
12190 specialize R. */
12193 (DECL_TEMPLATE_RESULT
12199 /* Check to see if we already have this specialization. */
12201 {
12205 }
12207 /* We can see more levels of arguments than parameters if
12208 there was a specialization of a member template, like
12209 this:
12211 template <class T> struct S { template <class U> void f(); }
12212 template <> template <class U> void S<int>::f(U);
12214 Here, we'll be substituting into the specialization,
12215 because that's where we can find the code we actually
12216 want to generate, but we'll have enough arguments for
12217 the most general template.
12219 We also deal with the peculiar case:
12221 template <class T> struct S {
12222 template <class U> friend void f();
12223 };
12224 template <class U> void f() {}
12225 template S<int>;
12226 template void f<double>();
12228 Here, the ARGS for the instantiation of will be {int,
12229 double}. But, we only need as many ARGS as there are
12230 levels of template parameters in CODE_PATTERN. We are
12231 careful not to get fooled into reducing the ARGS in
12232 situations like:
12234 template <class T> struct S { template <class U> void f(U); }
12235 template <class T> template <> void S<T>::f(int) {}
12237 which we can spot because the pattern will be a
12238 specialization in this case. */
12245 }
12246 else
12247 {
12248 /* This special case arises when we have something like this:
12250 template <class T> struct S {
12251 friend void f<int>(int, double);
12252 };
12254 Here, the DECL_TI_TEMPLATE for the friend declaration
12255 will be an IDENTIFIER_NODE. We are being called from
12256 tsubst_friend_function, and we want only to create a
12257 new decl (R) with appropriate types so that we can call
12258 determine_specialization. */
12261 }
12278 /* If we hit excessive deduction depth, the type is bogus even if
12279 it isn't error_mark_node, so don't build a decl. */
12283 /* We do NOT check for matching decls pushed separately at this
12284 point, as they may not represent instantiations of this
12285 template, and in any case are considered separate under the
12286 discrete model. */
12290 /* Clear out the mangled name and RTL for the instantiation. */
12293 /* Leave DECL_INITIAL set on deleted instantiations. */
12298 /* OpenMP UDRs have the only argument a reference to the declared
12299 type. We want to diagnose if the declared type is a reference,
12300 which is invalid, but as references to references are usually
12301 quietly merged, diagnose it here. */
12303 {
12304 tree argtype
12309 "reference type %qT in "
12313 argtype);
12314 }
12317 /* Type-conversion operator. Reconstruct the name, in
12318 case it's the name of one of the template's parameters. */
12328 {
12332 }
12339 /* If this is an instantiation of a function with internal
12340 linkage, we already know what object file linkage will be
12341 assigned to the instantiation. */
12350 /* We'll re-clone as appropriate in instantiate_template. */
12353 /* If we aren't complaining now, return on error before we register
12354 the specialization so that we'll complain eventually. */
12360 /* When instantiating a constrained member, substitute
12361 into the constraints to create a new constraint. */
12364 {
12367 }
12369 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
12370 this in the special friend case mentioned above where
12371 GEN_TMPL is NULL. */
12373 {
12378 tree new_r
12381 /* We instantiated this while substituting into
12382 the type earlier (template/friend54.C). */
12385 /* We're not supposed to instantiate default arguments
12386 until they are called, for a template. But, for a
12387 declaration like:
12389 template <class T> void f ()
12390 { extern void g(int i = T()); }
12392 we should do the substitution when the template is
12393 instantiated. We handle the member function case in
12394 instantiate_class_template since the default arguments
12395 might refer to other members of the class. */
12400 }
12401 else
12404 /* Copy the list of befriending classes. */
12408 {
12412 }
12415 {
12419 /* If this is an instantiation of a member template, clone it.
12420 If it isn't, that'll be handled by
12421 clone_constructors_and_destructors. */
12424 }
12435 /* Possibly limit visibility based on template args. */
12438 {
12442 }
12451 }
12453 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
12455 static tree
12457 tree lambda_fntype)
12458 {
12459 /* We can get here when processing a member function template,
12460 member class template, or template template parameter. */
12463 tree spec;
12464 tree tmpl_args;
12465 tree full_args;
12466 tree r;
12470 {
12471 /* Template template parameter is treated here. */
12475 /* If we get a real template back, return it. This can happen in
12476 the context of most_specialized_partial_spec. */
12479 else
12480 /* The new TEMPLATE_DECL was built in
12481 reduce_template_parm_level. */
12484 }
12487 {
12488 /* We might already have an instance of this template.
12489 The ARGS are for the surrounding class type, so the
12490 full args contain the tsubst'd args for the context,
12491 plus the innermost args from the template decl. */
12495 /* Because this is a template, the arguments will still be
12496 dependent, even after substitution. If
12497 PROCESSING_TEMPLATE_DECL is not set, the dependency
12498 predicates will short-circuit. */
12506 /* If this is a default template template argument,
12507 tsubst might not have changed anything. */
12515 }
12517 /* Make a new template decl. It will be similar to the
12518 original, but will record the current template arguments.
12519 We also create a new function declaration, which is just
12520 like the old one, but points to this new template, rather
12521 than the old one. */
12526 // Build new template info linking to the original template decl.
12528 {
12531 }
12532 else
12535 /* The template parameters for this new template are all the
12536 template parameters for the old template, except the
12537 outermost level of parameters. */
12540 complain);
12544 {
12545 tree new_type;
12553 /* For a partial specialization, we need to keep pointing to
12554 the primary template. */
12560 }
12561 else
12562 {
12563 tree new_decl;
12567 else
12577 {
12580 }
12581 else
12582 {
12585 }
12586 }
12596 /* Record this non-type partial instantiation. */
12602 }
12604 /* True if FN is the op() for a lambda in an uninstantiated template. */
12606 bool
12608 {
12613 }
12615 /* True if FN is the op() for a lambda regenerated from a lambda in an
12616 uninstantiated template. */
12618 bool
12620 {
12623 }
12625 /* We're instantiating a variable from template function TCTX. Return the
12626 corresponding current enclosing scope. This gets complicated because lambda
12627 functions in templates are regenerated rather than instantiated, but generic
12628 lambda functions are subsequently instantiated. */
12630 static tree
12632 {
12640 {
12651 {
12655 }
12657 }
12659 }
12661 /* Substitute the ARGS into the T, which is a _DECL. Return the
12662 result of the substitution. Issue error and warning messages under
12663 control of COMPLAIN. */
12665 static tree
12667 {
12668 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
12669 location_t saved_loc;
12674 /* Set the filename and linenumber to improve error-reporting. */
12679 {
12689 {
12697 {
12698 /* If there is a local specialization that isn't a
12699 parameter pack, it means that we're doing a "simple"
12700 substitution from inside tsubst_pack_expansion. Just
12701 return the local specialization (which will be a single
12702 parm). */
12709 /* Expand the TYPE_PACK_EXPANSION that provides the types for
12710 the parameters in this function parameter pack. */
12714 {
12717 /* Zero-length parameter packs are boring. Just substitute
12718 into the chain. */
12722 }
12723 else
12724 {
12725 /* All we did was update the type. Make a note of that. */
12728 }
12729 }
12731 /* Loop through all of the parameters we'll build. When T is
12732 a function parameter pack, LEN is the number of expanded
12733 types in EXPANDED_TYPES; otherwise, LEN is 1. */
12736 {
12743 /* We're on the Ith parameter of the function parameter
12744 pack. */
12745 {
12746 /* Get the Ith type. */
12749 /* Rename the parameter to include the index. */
12752 }
12754 /* We're dealing with a normal parameter. */
12762 {
12765 else
12768 }
12778 /* Keep track of the first new parameter we
12779 generate. That's what will be returned to the
12780 caller. */
12784 /* Build a proper chain of parameters when substituting
12785 into a function parameter pack. */
12788 }
12790 /* If cp_unevaluated_operand is set, we're just looking for a
12791 single dummy parameter, so don't keep going. */
12796 /* FIRST_R contains the start of the chain we've built. */
12798 }
12802 {
12809 {
12810 /* This field is a lambda capture pack. Return a TREE_VEC of
12811 the expanded fields to instantiate_class_template_1 and
12812 store them in the specializations hash table as a
12813 NONTYPE_ARGUMENT_PACK so that tsubst_copy can find them. */
12817 {
12820 }
12821 else
12822 {
12823 /* All we did was update the type. Make a note of that. */
12826 }
12827 }
12830 {
12833 {
12837 }
12847 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
12848 number of bits. */
12854 {
12855 /* Set up DECL_TEMPLATE_INFO so that we can get at the
12856 NSDMI in perform_member_init. Still set DECL_INITIAL
12857 so that we know there is one. */
12862 }
12863 /* We don't have to set DECL_CONTEXT here; it is set by
12864 finish_member_declaration. */
12872 }
12875 {
12880 }
12881 }
12885 /* We reach here only for member using decls. We also need to check
12886 uses_template_parms because DECL_DEPENDENT_P is not set for a
12887 using-declaration that designates a member of the current
12888 instantiation (c++/53549). */
12891 {
12895 {
12900 {
12904 {
12907 }
12908 else
12909 {
12912 }
12914 }
12915 }
12916 else
12917 {
12923 else
12924 {
12927 }
12928 }
12929 }
12930 else
12931 {
12934 }
12939 {
12942 tree spec;
12944 tree ctx;
12953 {
12954 /* If this is the canonical decl, we don't have to
12955 mess with instantiations, and often we can't (for
12956 typename, template type parms and such). Note that
12957 TYPE_NAME is not correct for the above test if
12958 we've copied the type for a typedef. */
12964 }
12966 /* Check to see if we already have the specialization we
12967 need. */
12970 {
12971 /* T is a static data member or namespace-scope entity.
12972 We have to substitute into namespace-scope variables
12973 (not just variable templates) because of cases like:
12975 template <class T> void f() { extern T t; }
12977 where the entity referenced is not known until
12978 instantiation time. */
12982 {
12984 complain,
12986 /* If CTX is unchanged, then T is in fact the
12987 specialization we want. That situation occurs when
12988 referencing a static data member within in its own
12989 class. We can use pointer equality, rather than
12990 same_type_p, because DECL_CONTEXT is always
12991 canonical... */
12993 /* ... unless T is a member template; in which
12994 case our caller can be willing to create a
12995 specialization of that template represented
12996 by T. */
13000 }
13003 {
13008 argvec = (coerce_innermost_template_parms
13016 }
13017 }
13018 else
13019 {
13020 /* A local variable. */
13022 /* Subsequent calls to pushdecl will fill this in. */
13024 /* Unless this is a reference to a static variable from an
13025 enclosing function, in which case we need to fill it in now. */
13027 {
13031 }
13033 }
13034 /* If we already have the specialization we need, there is
13035 nothing more to do. */
13037 {
13040 }
13042 /* Create a new node for the specialization we need. */
13045 {
13048 else
13056 {
13057 /* Mask off any template args past the variable's context so we
13058 don't replace the auto with an unrelated argument. */
13062 /* This should never happen with the new lambda instantiation
13063 model, but keep the handling just in case. */
13066 }
13068 }
13070 {
13071 /* Even if the original location is out of scope, the
13072 newly substituted one is not. */
13079 {
13080 /* It may seem that this case cannot occur, since:
13082 typedef void f();
13083 void g() { f x; }
13085 declares a function, not a variable. However:
13087 typedef void f();
13088 template <typename T> void g() { T t; }
13089 template void g<f>();
13091 is an attempt to declare a variable with function
13092 type. */
13094 /* R is not yet sufficiently initialized, so we
13095 just use its name. */
13098 }
13100 /* Wait until cp_finish_decl to set this again, to handle
13101 circular dependency (template/instantiate6.C). */
13106 {
13111 {
13114 }
13116 }
13120 }
13126 /* Clear out the mangled name and RTL for the instantiation. */
13130 /* The initializer must not be expanded until it is required;
13131 see [temp.inst]. */
13135 {
13138 /* Possibly limit visibility based on template args. */
13141 {
13145 }
13147 }
13150 {
13151 /* A static data member declaration is always marked
13152 external when it is declared in-class, even if an
13153 initializer is present. We mimic the non-template
13154 processing here. */
13162 }
13163 else
13164 {
13169 }
13177 /* Preserve a typedef that names a type. */
13179 {
13183 /* An alias template specialization can be dependent
13184 even if its underlying type is not. */
13186 }
13189 }
13194 }
13195 #undef RETURN
13197 out:
13198 /* Restore the file and line information. */
13202 }
13204 /* Substitute into the ARG_TYPES of a function type.
13205 If END is a TREE_CHAIN, leave it and any following types
13206 un-substituted. */
13208 static tree
13210 tree args,
13211 tree end,
13212 tsubst_flags_t complain,
13213 tree in_decl)
13214 {
13215 tree remaining_arg_types;
13219 tree default_arg;
13230 {
13231 /* For a pack expansion, perform substitution on the
13232 entire expression. Later on, we'll handle the arguments
13233 one-by-one. */
13238 /* So that we'll spin through the parameters, one by one. */
13240 else
13241 {
13242 /* We only partially substituted into the parameter
13243 pack. Our type is TYPE_PACK_EXPANSION. */
13246 }
13247 }
13260 {
13262 {
13266 }
13268 }
13269 /* DR 657. */
13273 /* Do array-to-pointer, function-to-pointer conversion, and ignore
13274 top-level qualifiers as required. */
13277 /* We do not substitute into default arguments here. The standard
13278 mandates that they be instantiated only when needed, which is
13279 done in build_over_call. */
13282 /* Except that we do substitute default arguments under tsubst_lambda_expr,
13283 since the new op() won't have any associated template arguments for us
13284 to refer to later. */
13290 {
13291 /* We've instantiated a template before its default arguments
13292 have been parsed. This can happen for a nested template
13293 class, and is not an error unless we require the default
13294 argument in a call of this function. */
13295 remaining_arg_types =
13298 }
13299 else
13300 remaining_arg_types =
13302 }
13305 }
13307 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
13308 *not* handle the exception-specification for FNTYPE, because the
13309 initial substitution of explicitly provided template parameters
13310 during argument deduction forbids substitution into the
13311 exception-specification:
13313 [temp.deduct]
13315 All references in the function type of the function template to the
13316 corresponding template parameters are replaced by the specified tem-
13317 plate argument values. If a substitution in a template parameter or
13318 in the function type of the function template results in an invalid
13319 type, type deduction fails. [Note: The equivalent substitution in
13320 exception specifications is done only when the function is instanti-
13321 ated, at which point a program is ill-formed if the substitution
13322 results in an invalid type.] */
13324 static tree
13326 tree args,
13327 tsubst_flags_t complain,
13328 tree in_decl)
13329 {
13330 tree return_type;
13332 tree fntype;
13334 /* The TYPE_CONTEXT is not used for function/method types. */
13337 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
13338 failure. */
13342 {
13343 /* Substitute the argument types. */
13355 {
13356 /* DR 1207: 'this' is in scope in the trailing return type. */
13358 }
13360 /* Substitute the return type. */
13364 {
13367 }
13368 }
13369 else
13370 /* Substitute the return type. */
13375 /* DR 486 clarifies that creation of a function type with an
13376 invalid return type is a deduction failure. */
13379 {
13381 {
13384 else
13386 }
13388 }
13389 /* And DR 657. */
13394 {
13395 /* Substitute the argument types. */
13400 }
13402 /* Construct a new type node and return it. */
13404 {
13409 }
13410 else
13411 {
13413 /* Don't pick up extra function qualifiers from the basetype. */
13416 {
13417 /* [temp.deduct]
13419 Type deduction may fail for any of the following
13420 reasons:
13422 -- Attempting to create "pointer to member of T" when T
13423 is not a class type. */
13426 r);
13428 }
13433 }
13440 }
13442 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
13443 ARGS into that specification, and return the substituted
13444 specification. If there is no specification, return NULL_TREE. */
13446 static tree
13448 tree args,
13449 tsubst_flags_t complain,
13450 tree in_decl,
13452 {
13453 tree specs;
13454 tree new_specs;
13459 {
13460 /* A noexcept-specifier. */
13465 {
13466 /* Defer instantiation of noexcept-specifiers to avoid
13467 excessive instantiations (c++/49107). */
13470 {
13471 /* We already partially instantiated this member template,
13472 so combine the new args with the old. */
13477 }
13478 else
13479 {
13482 }
13483 }
13484 else
13485 new_specs = tsubst_copy_and_build
13489 }
13491 {
13494 else
13496 {
13497 tree spec;
13502 {
13503 /* Expand the pack expansion type. */
13506 in_decl);
13512 else
13513 {
13514 /* We're substituting into a member template, so
13515 we got a TYPE_PACK_EXPANSION back. Add that
13516 expansion and move on. */
13520 expanded_specs,
13521 complain);
13524 }
13525 }
13528 {
13531 else
13536 complain);
13537 }
13540 }
13541 }
13543 }
13545 /* Take the tree structure T and replace template parameters used
13546 therein with the argument vector ARGS. IN_DECL is an associated
13547 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
13548 Issue error and warning messages under control of COMPLAIN. Note
13549 that we must be relatively non-tolerant of extensions here, in
13550 order to preserve conformance; if we allow substitutions that
13551 should not be allowed, we may allow argument deductions that should
13552 not succeed, and therefore report ambiguous overload situations
13553 where there are none. In theory, we could allow the substitution,
13554 but indicate that it should have failed, and allow our caller to
13555 make sure that the right thing happens, but we don't try to do this
13556 yet.
13558 This function is used for dealing with types, decls and the like;
13559 for expressions, use tsubst_expr or tsubst_copy. */
13561 tree
13563 {
13586 else
13591 /* Reuse typedefs. We need to do this to handle dependent attributes,
13592 such as attribute aligned. */
13595 {
13599 {
13600 /* DECL represents an alias template and we want to
13601 instantiate it. */
13605 }
13609 {
13613 }
13618 else
13619 /* The typedef is from a non-template context. */
13623 {
13625 r = cp_build_qualified_type_real
13629 }
13630 else
13631 {
13632 /* We don't have an instantiation yet, so drop the typedef. */
13637 }
13638 }
13655 {
13681 {
13687 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
13688 needed. */
13694 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
13695 with TREE_SIDE_EFFECTS that indicates this is not an integral
13696 constant expression. */
13699 {
13702 }
13705 }
13711 {
13717 /* Early in template argument deduction substitution, we don't
13718 want to reduce the level of 'auto', or it will be confused
13719 with a normal template parm in subsequent deduction. */
13731 {
13735 {
13736 /* See through ARGUMENT_PACK_SELECT arguments. */
13738 /* If the selected argument is an expansion E, that most
13739 likely means we were called from
13740 gen_elem_of_pack_expansion_instantiation during the
13741 substituting of pack an argument pack (which Ith
13742 element is a pack expansion, where I is
13743 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
13744 In this case, the Ith element resulting from this
13745 substituting is going to be a pack expansion, which
13746 pattern is the pattern of E. Let's return the
13747 pattern of E, and
13748 gen_elem_of_pack_expansion_instantiation will
13749 build the resulting pack expansion from it. */
13751 {
13752 /* Make sure we aren't throwing away arg info. */
13755 }
13756 }
13757 }
13762 {
13764 /* If ARG is an argument pack, we don't actually want to
13765 perform a substitution here, because substitutions
13766 for argument packs are only done
13767 element-by-element. We can get to this point when
13768 substituting the type of a non-type template
13769 parameter pack, when that type actually contains
13770 template parameter packs from an outer template, e.g.,
13772 template<typename... Types> struct A {
13773 template<Types... Values> struct B { };
13774 }; */
13778 {
13784 return cp_build_qualified_type_real
13786 }
13788 {
13789 /* We are processing a type constructed from a
13790 template template parameter. */
13801 /* Consider this code:
13803 template <template <class> class Template>
13804 struct Internal {
13805 template <class Arg> using Bind = Template<Arg>;
13806 };
13808 template <template <class> class Template, class Arg>
13809 using Instantiate = Template<Arg>; //#0
13811 template <template <class> class Template,
13812 class Argument>
13813 using Bind =
13814 Instantiate<Internal<Template>::template Bind,
13815 Argument>; //#1
13817 When #1 is parsed, the
13818 BOUND_TEMPLATE_TEMPLATE_PARM representing the
13819 parameter `Template' in #0 matches the
13820 UNBOUND_CLASS_TEMPLATE representing the argument
13821 `Internal<Template>::template Bind'; We then want
13822 to assemble the type `Bind<Argument>' that can't
13823 be fully created right now, because
13824 `Internal<Template>' not being complete, the Bind
13825 template cannot be looked up in that context. So
13826 we need to "store" `Bind<Argument>' for later
13827 when the context of Bind becomes complete. Let's
13828 store that in a TYPENAME_TYPE. */
13832 argvec),
13833 typename_type,
13834 complain);
13836 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
13837 are resolving nested-types in the signature of a
13838 member function templates. Otherwise ARG is a
13839 TEMPLATE_DECL and is the real template to be
13840 instantiated. */
13848 complain);
13849 return cp_build_qualified_type_real
13851 }
13854 else
13855 /* TEMPLATE_PARM_INDEX. */
13857 }
13860 /* This can happen during the attempted tsubst'ing in
13861 unify. This means that we don't yet have any information
13862 about the template parameter in question. */
13865 /* If we get here, we must have been looking at a parm for a
13866 more deeply nested template. Make a new version of this
13867 template parameter, but with a lower level. */
13869 {
13874 {
13876 r = cp_build_qualified_type_real
13880 }
13887 /* Break infinite recursion when substituting the constraints
13889 else
13890 {
13901 {
13902 /* Propagate constraints on placeholders. */
13907 {
13911 }
13912 }
13915 /* We have reduced the level of the template
13916 template parameter, but not the levels of its
13917 template parameters, so canonical_type_parameter
13918 will not be able to find the canonical template
13919 template parameter for this level. Thus, we
13920 require structural equality checking to compare
13921 TEMPLATE_TEMPLATE_PARMs. */
13925 else
13929 {
13931 /* We might need to substitute into the types of non-type
13932 template parameters. */
13944 }
13945 }
13949 /* OK, now substitute the type of the non-type parameter. We
13950 couldn't do it earlier because it might be an auto parameter,
13951 and we wouldn't need to if we had an argument. */
13960 }
13963 }
13966 {
13974 {
13978 }
13981 {
13985 }
13988 {
13992 }
13998 }
14001 /* We should never be tsubsting a binfo. */
14005 /* A vector of template arguments. */
14011 {
14015 /* [temp.deduct]
14017 Type deduction may fail for any of the following
14018 reasons:
14020 -- Attempting to create a pointer to reference type.
14021 -- Attempting to create a reference to a reference type or
14022 a reference to void.
14024 Core issue 106 says that creating a reference to a reference
14025 during instantiation is no longer a cause for failure. We
14026 only enforce this check in strict C++98 mode. */
14030 {
14033 /* We keep track of the last time we issued this error
14034 message to avoid spewing a ton of messages during a
14035 single bad template instantiation. */
14038 {
14043 else
14046 }
14049 }
14053 {
14055 {
14058 type);
14059 else
14061 type);
14062 }
14064 }
14066 {
14070 }
14072 /* In C++0x, during template argument substitution, when there is an
14073 attempt to create a reference to a reference type, reference
14074 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
14076 "If a template-argument for a template-parameter T names a type
14077 that is a reference to a type A, an attempt to create the type
14078 'lvalue reference to cv T' creates the type 'lvalue reference to
14079 A,' while an attempt to create the type type rvalue reference to
14080 cv T' creates the type T"
14081 */
14082 r = cp_build_reference_type
14085 else
14090 /* Will this ever be needed for TYPE_..._TO values? */
14094 }
14096 {
14099 {
14100 /* [temp.deduct]
14102 Type deduction may fail for any of the following
14103 reasons:
14105 -- Attempting to create "pointer to member of T" when T
14106 is not a class type. */
14110 }
14112 {
14116 }
14118 {
14122 }
14125 {
14126 /* The type of the implicit object parameter gets its
14127 cv-qualifiers from the FUNCTION_TYPE. */
14128 tree memptr;
14129 tree method_type
14134 complain);
14135 }
14136 else
14139 complain);
14140 }
14143 {
14144 tree fntype;
14145 tree specs;
14150 /* Substitute the exception specification. */
14158 }
14160 {
14165 /* As an optimization, we avoid regenerating the array type if
14166 it will obviously be the same as T. */
14170 /* These checks should match the ones in create_array_type_for_decl.
14172 [temp.deduct]
14174 The deduction may fail for any of the following reasons:
14176 -- Attempting to create an array with an element type that
14177 is void, a function type, or a reference type, or [DR337]
14178 an abstract class type. */
14184 {
14188 }
14196 {
14199 }
14202 }
14205 {
14217 {
14221 }
14223 {
14224 /* Normally, make_typename_type does not require that the CTX
14225 have complete type in order to allow things like:
14227 template <class T> struct S { typename S<T>::X Y; };
14229 But, such constructs have already been resolved by this
14230 point, so here CTX really should have complete type, unless
14231 it's a partial instantiation. */
14234 {
14238 }
14239 }
14246 {
14249 }
14252 {
14254 {
14258 else
14260 }
14262 {
14266 else
14268 }
14269 }
14271 return cp_build_qualified_type_real
14273 }
14276 {
14288 }
14291 {
14292 tree type;
14308 complain);
14309 }
14312 {
14313 tree type;
14324 {
14326 {
14330 }
14333 }
14344 else
14345 {
14349 /* In a template ~id could be either a complement expression
14350 or an unqualified-id naming a destructor; if instantiating
14351 it produces an expression, it's not an id-expression or
14352 member access. */
14355 }
14360 }
14363 {
14367 }
14371 {
14372 tree r;
14376 else
14384 }
14399 /* We should use one of the expression tsubsts for these codes. */
14405 }
14406 }
14408 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
14409 expression on the left-hand side of the "." or "->" operator. A
14410 baselink indicates a function from a base class. Both the
14411 BASELINK_ACCESS_BINFO and the base class referenced may indicate
14412 bases of the template class, rather than the instantiated class.
14413 In addition, lookups that were not ambiguous before may be
14414 ambiguous now. Therefore, we perform the lookup again. */
14416 static tree
14419 {
14432 {
14439 }
14447 {
14452 }
14454 /* If lookup found a single function, mark it as used at this point.
14455 (If it lookup found multiple functions the one selected later by
14456 overload resolution will be marked as used at that point.) */
14464 {
14465 /* Add back the template arguments, if present. */
14471 /* Update the conversion operator type. */
14473 }
14479 {
14481 qualifying_scope,
14482 object_type);
14484 /* We need to call adjust_result_of_qualified_name_lookup in case the
14485 destructor names a base class, but we unset BASELINK_QUALIFIED_P
14486 so that we still get virtual function binding. */
14488 }
14491 }
14493 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
14494 true if the qualified-id will be a postfix-expression in-and-of
14495 itself; false if more of the postfix-expression follows the
14496 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
14497 of "&". */
14499 static tree
14503 {
14504 tree expr;
14505 tree scope;
14506 tree name;
14508 tree template_args;
14513 /* Figure out what name to look up. */
14516 {
14526 }
14527 else
14528 {
14531 }
14533 /* Substitute into the qualifying scope. When there are no ARGS, we
14534 are just trying to simplify a non-dependent expression. In that
14535 case the qualifying scope may be dependent, and, in any case,
14536 substituting will not help. */
14539 {
14542 }
14543 else
14547 {
14554 }
14557 {
14559 {
14560 /* A BIT_NOT_EXPR is used to represent a destructor. */
14562 {
14566 }
14567 else
14570 }
14571 else
14575 {
14577 {
14581 }
14583 }
14584 }
14587 {
14589 scope);
14590 /* Remember that there was a reference to this entity. */
14593 }
14596 {
14602 }
14605 {
14608 complain);
14609 else
14611 }
14617 {
14618 expr = (adjust_result_of_qualified_name_lookup
14620 expr = (finish_qualified_id_expr
14624 }
14626 /* Expressions do not generally have reference type. */
14628 /* However, if we're about to form a pointer-to-member, we just
14629 want the referenced member referenced. */
14637 }
14639 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
14640 initializer, DECL is the substituted VAR_DECL. Other arguments are as
14641 for tsubst. */
14643 static tree
14646 {
14653 {
14654 /* If we had an initializer but it
14655 instantiated to nothing,
14656 value-initialize the object. This will
14657 only occur when the initializer was a
14658 pack expansion where the parameter packs
14659 used in that expansion were of length
14660 zero. */
14662 complain);
14667 }
14670 }
14672 /* Like tsubst, but deals with expressions. This function just replaces
14673 template parms; to finish processing the resultant expression, use
14674 tsubst_copy_and_build or tsubst_expr. */
14676 static tree
14678 {
14680 tree r;
14688 {
14693 {
14694 /* We get here for a use of 'this' in an NSDMI. */
14698 /* This can happen for a parameter name used later in a function
14699 declaration (such as in a late-specified return type). Just
14700 make a dummy decl, since it's only used for its type. */
14703 /* Give it the template pattern as its context; its true context
14704 hasn't been instantiated yet and this is good enough for
14705 mangling. */
14707 }
14716 {
14717 tree enum_type;
14718 tree v;
14722 /* There is no need to substitute into namespace-scope
14723 enumerators. */
14726 /* If ARGS is NULL, then T is known to be non-dependent. */
14730 /* Unfortunately, we cannot just call lookup_name here.
14731 Consider:
14733 template <int I> int f() {
14734 enum E { a = I };
14735 struct S { void g() { E e = a; } };
14736 };
14738 When we instantiate f<7>::S::g(), say, lookup_name is not
14739 clever enough to find f<7>::a. */
14740 enum_type
14750 /* We didn't find the name. That should never happen; if
14751 name-lookup found it during preliminary parsing, we
14752 should find it again here during instantiation. */
14754 }
14759 {
14760 /* Check for a local specialization set up by
14761 tsubst_pack_expansion. */
14763 {
14767 }
14769 /* When retrieving a capture pack from a generic lambda, remove the
14770 lambda call op's own template argument list from ARGS. Only the
14771 template arguments active for the closure type should be used to
14772 retrieve the pack specialization. */
14778 /* Otherwise return the full NONTYPE_ARGUMENT_PACK that
14779 tsubst_decl put in the hash table. */
14781 }
14784 {
14785 tree ctx;
14790 {
14793 {
14797 }
14799 }
14800 }
14810 {
14813 {
14814 /* First try name lookup to find the instantiation. */
14817 {
14818 /* Make sure that the one we found is the one we want. */
14822 }
14826 else
14827 {
14828 /* This can happen for a variable used in a
14829 late-specified return type of a local lambda, or for a
14830 local static or constant. Building a new VAR_DECL
14831 should be OK in all those cases. */
14834 /* Avoid infinite recursion (79640). */
14837 {
14838 /* We can't call cp_finish_decl, so handle the
14839 initializer by hand. */
14854 }
14861 }
14862 /* Remember this for subsequent uses. */
14865 }
14866 }
14867 else
14877 /* An OVERLOAD will always be a non-dependent overload set; an
14878 overload set from function scope will just be represented with an
14879 IDENTIFIER_NODE, and from class scope with a BASELINK. */
14881 /* We must have marked any lookups as persistent. */
14897 {
14898 /* Template template argument like the following example need
14899 special treatment:
14901 template <template <class> class TT> struct C {};
14902 template <class T> struct D {
14903 template <class U> struct E {};
14904 C<E> c; // #1
14905 };
14906 D<int> d; // #2
14908 We are processing the template argument `E' in #1 for
14909 the template instantiation #2. Originally, `E' is a
14910 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
14911 have to substitute this with one having context `D<int>'. */
14915 {
14916 /* When rewriting a constructor into a deduction guide, a
14917 non-dependent name can become dependent, so memtmpl<args>
14918 becomes context::template memtmpl<args>. */
14922 }
14924 }
14925 else
14926 /* Ordinary template template argument. */
14937 {
14941 }
14946 {
14955 /* We only want to compute the number of arguments. */
14958 else
14965 {
14967 /* Set TREE_USED for the benefit of -Wunused. */
14971 }
14979 {
14984 else
14990 else
14993 }
14994 else
14996 }
14998 {
15006 }
15007 /* Fall through */
15023 {
15027 }
15030 {
15031 tree object;
15032 tree name;
15037 {
15041 }
15044 {
15054 }
15059 in_decl);
15060 else
15063 }
15101 {
15105 }
15108 {
15113 }
15116 {
15120 }
15123 {
15131 }
15137 {
15144 }
15147 {
15154 }
15157 {
15164 }
15167 {
15168 /* Substituted template arguments */
15177 }
15180 {
15200 }
15225 /* Fall through. */
15228 {
15231 }
15232 else
15236 /* This is handled by tsubst_copy_and_build. */
15240 {
15244 }
15247 /* We shouldn't have built any of these during initial template
15248 generation. Instead, they should be built during instantiation
15249 in response to the saved STMT_IS_FULL_EXPR_P setting. */
15253 {
15263 }
15281 {
15282 /* Instantiate any typedefs in the type. */
15287 }
15290 /* These can sometimes show up in a partial instantiation, but never
15291 involve template parms. */
15307 /* We shouldn't get here, but keep going if !flag_checking. */
15311 }
15312 }
15314 /* Helper function for tsubst_omp_clauses, used for instantiation of
15315 OMP_CLAUSE_DECL of clauses. */
15317 static tree
15319 tree in_decl)
15320 {
15324 /* Handle an OpenMP array section represented as a TREE_LIST (or
15325 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15326 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15327 TREE_LIST. We can handle it exactly the same as an array section
15328 (purpose, value, and a chain), even though the nomenclature
15329 (low_bound, length, etc) is different. */
15331 {
15332 tree low_bound
15338 in_decl);
15347 }
15350 /* Undo convert_from_reference tsubst_expr could have called. */
15356 }
15358 /* Like tsubst_copy, but specifically for OpenMP clauses. */
15360 static tree
15363 {
15368 {
15374 {
15377 {
15383 }
15384 /* FALLTHRU */
15399 in_decl);
15431 {
15434 {
15441 }
15442 else
15444 }
15447 in_decl);
15453 in_decl);
15461 in_decl);
15463 {
15466 }
15471 else
15474 in_decl,
15498 }
15501 {
15511 /* tsubst_expr on SCOPE_REF results in returning
15512 finish_non_static_data_member result. Undo that here. */
15516 {
15521 {
15525 CASE_CONVERT:
15534 /* FALLTHRU */
15538 }
15539 }
15545 {
15548 {
15551 }
15552 }
15556 }
15557 }
15561 {
15566 {
15569 }
15570 }
15572 }
15574 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
15576 static tree
15578 tree in_decl)
15579 {
15580 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
15600 {
15603 else
15604 {
15608 }
15609 }
15614 #undef RECUR
15615 }
15617 /* Used to temporarily communicate the list of #pragma omp parallel
15618 clauses to #pragma omp for instantiation if they are combined
15619 together. */
15623 /* Substitute one OMP_FOR iterator. */
15625 static void
15630 {
15631 #define RECUR(NODE) \
15632 tsubst_expr ((NODE), args, complain, in_decl, \
15633 integral_constant_expression_p)
15640 {
15643 }
15649 {
15650 /* We need to jump through some hoops to handle declarations in the
15651 init-statement, since we might need to handle auto deduction,
15652 but we need to keep control of initialization. */
15656 }
15657 else
15658 {
15660 {
15663 {
15667 {
15671 CASE_CONVERT:
15679 {
15682 }
15683 /* FALLTHRU */
15687 }
15688 }
15689 }
15690 else
15692 }
15703 {
15705 {
15706 /* Declare the variable, but don't let that initialize it. */
15711 }
15716 {
15721 }
15722 else
15729 }
15732 {
15733 /* Declare and initialize the variable. */
15736 }
15738 {
15742 {
15744 {
15750 {
15753 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
15758 }
15761 {
15763 decl);
15765 }
15768 {
15770 decl);
15772 }
15773 else
15775 }
15778 }
15780 {
15785 {
15788 }
15789 }
15790 }
15793 {
15797 }
15798 else
15802 {
15813 {
15821 }
15822 else
15828 {
15834 }
15838 {
15846 }
15847 else
15853 }
15859 #undef RECUR
15860 }
15862 /* Helper function of tsubst_expr, find OMP_TEAMS inside
15863 of OMP_TARGET's body. */
15865 static tree
15867 {
15870 {
15879 }
15881 }
15883 /* Helper function for tsubst_expr. For decomposition declaration
15884 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
15885 also the corresponding decls representing the identifiers
15886 of the decomposition declaration. Return DECL if successful
15887 or error_mark_node otherwise, set *FIRST to the first decl
15888 in the list chained through DECL_CHAIN and *CNT to the number
15889 of such decls. */
15891 static tree
15895 {
15900 decl2
15905 {
15907 {
15910 }
15927 {
15930 }
15931 else
15933 }
15936 }
15938 /* Like tsubst_copy for expressions, etc. but also does semantic
15939 processing. */
15941 tree
15944 {
15945 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
15946 #define RECUR(NODE) \
15947 tsubst_expr ((NODE), args, complain, in_decl, \
15948 integral_constant_expression_p)
15951 tree r;
15952 location_t loc;
15964 {
15966 {
15967 tree_stmt_iterator i;
15971 }
15986 else
15996 {
15998 tree init;
16004 {
16014 else
16016 }
16018 {
16019 /* Don't build up decls for a variadic capture proxy, we'll
16020 instantiate the elements directly as needed. */
16022 }
16025 {
16026 /* We're in tsubst_lambda_expr, we've already inserted a new
16027 capture proxy, so look it up and register it. */
16033 }
16036 /* Don't copy the old closure; we'll create a new one in
16037 tsubst_lambda_expr. */
16039 else
16040 {
16044 {
16045 /* By marking the declaration as instantiated, we avoid
16046 trying to instantiate it. Since instantiate_decl can't
16047 handle local variables, and since we've already done
16048 all that needs to be done, that's the right thing to
16049 do. */
16054 /* Anonymous aggregates are a special case. */
16057 {
16060 {
16064 }
16066 }
16072 {
16077 }
16078 else
16079 {
16084 {
16085 /* For __PRETTY_FUNCTION__ we have to adjust the
16086 initializer. */
16090 }
16091 else
16095 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
16101 {
16103 tree first;
16109 }
16110 }
16111 }
16112 }
16115 }
16130 {
16138 {
16140 tree first;
16145 }
16146 else
16151 }
16177 else
16178 {
16185 }
16191 {
16200 }
16208 else
16216 else
16237 {
16244 }
16248 {
16250 tree label;
16257 }
16263 /* Computed goto's must be tsubst'd into. On the other hand,
16264 non-computed gotos must not be; the identifier in question
16265 will have no binding. */
16267 else
16273 {
16289 }
16294 {
16299 }
16300 else
16301 {
16306 else
16313 else
16319 else
16321 }
16325 {
16329 {
16331 /* Prevent instantiate_decl from trying to instantiate
16332 this variable. We've already done all that needs to be
16333 done. */
16336 }
16341 }
16347 {
16348 /* Local classes are not independent templates; they are
16349 instantiated along with their containing function. And this
16350 way we don't have to deal with pushing out of one local class
16351 to instantiate a member of another local class. */
16352 /* Closures are handled by the LAMBDA_EXPR. */
16362 }
16366 {
16367 tree condition;
16370 condition =
16372 args,
16381 }
16387 in_decl);
16424 {
16439 in_decl);
16441 {
16448 }
16460 integral_constant_expression_p);
16471 else
16472 {
16480 }
16484 }
16489 /* FALLTHRU */
16496 in_decl);
16513 in_decl);
16524 {
16527 {
16528 /* For combined target teams, ensure the num_teams and
16529 thread_limit clause expressions are evaluated on the host,
16530 before entering the target construct. */
16531 tree c;
16537 {
16546 OMP_CLAUSE_FIRSTPRIVATE);
16550 }
16551 }
16552 }
16612 {
16617 {
16620 }
16626 }
16627 else
16628 {
16635 {
16638 }
16641 {
16646 {
16649 }
16655 }
16656 else
16657 {
16661 }
16664 }
16668 {
16674 {
16678 {
16683 }
16687 }
16688 else
16689 {
16694 }
16695 }
16699 {
16703 }
16723 /* If the first operand was a statement, we're done with it. */
16727 complain));
16741 integral_constant_expression_p));
16742 }
16745 out:
16748 #undef RECUR
16749 #undef RETURN
16750 }
16752 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
16753 function. For description of the body see comment above
16754 cp_parser_omp_declare_reduction_exprs. */
16756 static void
16758 {
16764 tree_stmt_iterator tsi;
16775 {
16794 }
16796 {
16816 }
16817 }
16819 /* T is a postfix-expression that is not being used in a function
16820 call. Return the substituted version of T. */
16822 static tree
16824 tsubst_flags_t complain,
16825 tree in_decl)
16826 {
16830 else
16836 }
16838 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
16839 instantiation context. Instantiating a pack expansion containing a lambda
16840 might result in multiple lambdas all based on the same lambda in the
16841 template. */
16843 tree
16845 {
16859 else
16867 {
16879 else
16884 {
16893 }
16894 else
16895 {
16901 }
16902 }
16906 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
16924 else
16925 {
16926 /* Fix the type of 'this'. */
16932 {
16936 }
16937 else
16938 {
16942 }
16944 /* Let finish_function set this. */
16965 /* The capture list was built up in reverse order; fix that now. */
16972 }
16979 }
16981 /* Like tsubst but deals with expressions and performs semantic
16982 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
16984 tree
16986 tree args,
16987 tsubst_flags_t complain,
16988 tree in_decl,
16991 {
16992 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
16993 #define RECUR(NODE) \
16994 tsubst_copy_and_build (NODE, args, complain, in_decl, \
16996 integral_constant_expression_p)
16999 location_t loc;
17008 /* N3276 decltype magic only applies to calls at the top level or on the
17009 right side of a comma. */
17014 {
17017 /* Fall through. */
17019 {
17020 tree decl;
17021 cp_id_kind idk;
17026 {
17029 }
17031 /* Look up the name. */
17034 /* By convention, expressions use ERROR_MARK_NODE to indicate
17035 failure, not NULL_TREE. */
17041 integral_constant_expression_p,
17049 input_location);
17053 {
17057 }
17059 }
17062 {
17063 tree object;
17073 {
17078 }
17084 {
17087 }
17088 else
17095 else
17097 }
17100 {
17104 {
17105 /* A type conversion to reference type will be enclosed in
17106 such an indirect ref, but the substitution of the cast
17107 will have also added such an indirect ref. */
17109 }
17110 else
17118 }
17121 {
17125 }
17128 {
17132 {
17137 }
17139 /* We'll pass this to convert_nontype_argument again, we don't need
17140 to actually perform any conversion here. */
17146 flags));
17147 }
17150 {
17154 }
17161 {
17162 tree type;
17168 {
17173 }
17179 {
17197 }
17200 }
17234 else
17236 in_decl);
17271 {
17278 tree r = build_x_binary_op
17280 op0,
17282 ? ERROR_MARK
17284 op1,
17286 ? ERROR_MARK
17294 }
17297 {
17301 }
17314 {
17323 }
17328 /* Fall through */
17331 {
17332 tree r;
17338 {
17339 /* When there are no ARGS, we are trying to evaluate a
17340 non-dependent expression from the parser. Trying to do
17341 the substitutions may not work. */
17344 }
17345 else
17346 {
17351 else
17354 /*integral_constant_expression_p=*/
17358 }
17362 else
17366 {
17368 {
17370 {
17374 }
17375 else
17379 }
17381 }
17383 }
17386 {
17396 }
17412 {
17416 tree r = build_x_modify_expr
17419 /* TREE_NO_WARNING must be set if either the expression was
17420 parenthesized or it uses an operator such as >>= rather
17421 than plain assignment. In the former case, it was already
17422 set and must be copied. In the latter case,
17423 build_x_modify_expr sets it and it must not be reset
17424 here. */
17429 }
17434 /* Remember that there was a reference to this entity. */
17441 {
17446 tree ret;
17450 else
17451 {
17455 }
17457 /* If there was an initializer in the original tree, but it
17458 instantiated to an empty list, then we should pass a
17459 non-NULL empty vector to tell build_new that it was an
17460 empty initializer() rather than no initializer. This can
17461 only happen when the initializer is a pack expansion whose
17462 parameter packs are of length zero. */
17465 else
17466 {
17470 else
17471 {
17474 }
17475 }
17481 complain);
17489 }
17492 {
17498 complain));
17499 }
17502 {
17506 integral_constant_expression_p);
17508 op0,
17511 }
17514 {
17515 tree function;
17520 tree ret;
17523 /* Internal function with no arguments. */
17527 /* When we parsed the expression, we determined whether or
17528 not Koenig lookup should be performed. */
17531 {
17534 }
17536 {
17541 }
17543 {
17544 /* Do nothing; calling tsubst_copy_and_build on an identifier
17545 would incorrectly perform unqualified lookup again.
17547 Note that we can also have an IDENTIFIER_NODE if the earlier
17548 unqualified lookup found a member function; in that case
17549 koenig_p will be false and we do want to do the lookup
17550 again to find the instantiated member function.
17552 FIXME but doing that causes c++/15272, so we need to stop
17553 using IDENTIFIER_NODE in that situation. */
17555 }
17556 else
17557 {
17559 {
17565 }
17566 else
17571 /* Avoid error about taking the address of a constructor. */
17575 in_decl,
17577 integral_constant_expression_p);
17581 }
17586 {
17591 else
17592 {
17593 /* Expand the pack expansion and push each entry onto
17594 CALL_ARGS. */
17597 {
17602 {
17607 }
17608 }
17609 else
17610 {
17611 /* A partial substitution. Add one entry. */
17613 }
17614 }
17615 }
17617 /* We do not perform argument-dependent lookup if normal
17618 lookup finds a non-function, in accordance with the
17619 expected resolution of DR 218. */
17622 /* If lookup found a member function, the Koenig lookup is
17623 not appropriate, even if an unqualified-name was used
17624 to denote the function. */
17627 /* Only do this when substitution turns a dependent call
17628 into a non-dependent call. */
17636 {
17638 {
17639 /* For backwards compatibility and good diagnostics, try
17640 the unqualified lookup again if we aren't in SFINAE
17641 context. */
17642 tree unq = (tsubst_copy_and_build
17644 integral_constant_expression_p));
17646 {
17649 }
17652 {
17653 /* In a lambda fn, we have to be careful to not
17654 introduce new this captures. Legacy code can't
17655 be using lambdas anyway, so it's ok to be
17656 stricter. */
17661 "and no declarations were found by "
17662 "argument-dependent lookup at the point "
17669 else
17673 {
17684 {
17686 input_location);
17688 "declarations in dependent base %qT are "
17694 else
17698 }
17699 else
17701 "%qD declared here, later in the "
17704 {
17707 }
17708 }
17711 }
17712 }
17714 {
17719 }
17720 }
17722 /* Remember that there was a reference to this entity. */
17726 {
17729 }
17731 /* Put back tf_decltype for the actual call. */
17736 {
17740 {
17742 "wrong number of arguments to "
17745 }
17746 else
17748 input_location),
17753 /* Unsupported internal function with arguments. */
17755 }
17758 complain);
17760 {
17775 complain);
17776 else
17777 ret = (build_new_method_call
17782 complain));
17783 }
17784 else
17787 koenig_p,
17788 complain);
17793 {
17799 {
17805 {
17807 /* The thunk location is not interesting. */
17809 }
17810 }
17811 }
17814 }
17817 {
17823 {
17825 {
17830 }
17831 else
17832 {
17837 }
17839 }
17840 else
17841 {
17844 }
17848 }
17851 {
17856 input_location));
17857 }
17860 {
17868 {
17869 /* We have pack expansions, so expand those and
17870 create a new list out of it. */
17873 tree chain;
17876 /* Expand the argument expressions. */
17884 /* Build the rest of the list. */
17889 /* Determine the number of arguments. */
17891 {
17894 }
17897 else
17898 {
17899 /* Since we only performed a partial substitution into
17900 the argument pack, we only RETURN (a single list
17901 node. */
17908 }
17910 /* Convert the argument vectors into a TREE_LIST */
17913 {
17914 /* Grab the Ith values. */
17915 i--;
17918 value
17922 /* Build the list (backwards). */
17924 }
17927 }
17943 }
17946 {
17947 tree object;
17948 tree object_type;
17949 tree member;
17950 tree r;
17954 /* Remember that there was a reference to this entity. */
17965 else
17971 {
17976 }
17980 {
17982 {
17987 {
17990 }
17992 {
17997 }
17998 }
17999 }
18002 {
18003 /* Lookup the template functions now that we know what the
18004 scope is. */
18012 {
18015 args);
18016 member = (adjust_result_of_qualified_name_lookup
18018 object_type));
18019 }
18020 else
18021 {
18023 input_location);
18025 }
18026 }
18030 {
18032 {
18036 else
18039 }
18041 }
18045 complain);
18049 }
18056 {
18064 tree r;
18069 /* digest_init will do the wrong thing if we let it. */
18073 /* We do not want to process the index of aggregate
18074 initializers as they are identifier nodes which will be
18075 looked up by digest_init. */
18081 {
18083 /* An identifier index is looked up in the type
18084 being initialized, not the current scope. */
18089 {
18090 /* Substitute into the pack expansion. */
18092 in_decl);
18096 ;
18098 /* Just move the argument into place. */
18100 else
18101 {
18102 /* Update the length of the final CONSTRUCTOR
18103 arguments vector, and note that we will need to
18104 copy.*/
18107 }
18108 }
18109 else
18111 }
18114 {
18119 {
18121 {
18126 }
18127 else
18129 }
18130 }
18136 {
18141 }
18145 }
18148 {
18151 {
18154 }
18155 else
18156 {
18159 }
18160 }
18166 {
18167 /* We don't build decls for an instantiation of a
18168 variadic capture proxy, we instantiate the elements
18169 when needed. */
18172 }
18173 /* Fall through */
18176 {
18178 /* ??? We're doing a subset of finish_id_expression here. */
18180 && !processing_template_decl
18181 && !cp_unevaluated_operand
18184 {
18186 /* Replace an evaluated use of the thread_local variable with
18187 a call to its wrapper. */
18189 }
18194 /* If the original type was a reference, we'll be wrapped in
18195 the appropriate INDIRECT_REF. */
18198 }
18201 {
18205 }
18208 {
18209 tree object_ptr
18216 }
18223 {
18234 }
18237 {
18243 integral_constant_expression_p);
18247 /* If the resulting list of expression statement is empty,
18248 fold it further into void_node. */
18253 }
18256 {
18260 }
18263 /* We can get here for a constant initializer of non-dependent type.
18264 FIXME stop folding in cp_parser_initializer_clause. */
18265 {
18267 complain);
18269 }
18273 integral_constant_expression_p));
18279 {
18284 complain));
18285 }
18291 /* Handle Objective-C++ constructs, if appropriate. */
18292 {
18293 tree subst
18298 }
18300 }
18302 #undef RECUR
18303 #undef RETURN
18304 out:
18307 }
18309 /* Verify that the instantiated ARGS are valid. For type arguments,
18310 make sure that the type's linkage is ok. For non-type arguments,
18311 make sure they are constants if they are integral or enumerations.
18312 Emit an error under control of COMPLAIN, and return TRUE on error. */
18314 static bool
18316 {
18320 {
18330 }
18332 {
18333 /* [basic.link]: A name with no linkage (notably, the name
18334 of a class or enumeration declared in a local scope)
18335 shall not be used to declare an entity with linkage.
18336 This implies that names with no linkage cannot be used as
18337 template arguments
18339 DR 757 relaxes this restriction for C++0x. */
18344 {
18345 /* DR 488 makes use of a type with no linkage cause
18346 type deduction to fail. */
18348 {
18351 else
18354 }
18356 }
18357 /* In order to avoid all sorts of complications, we do not
18358 allow variably-modified types as template arguments. */
18360 {
18364 }
18365 }
18366 /* Class template and alias template arguments should be OK. */
18368 ;
18369 /* A non-type argument of integral or enumerated type must be a
18370 constant. */
18375 {
18379 }
18381 }
18383 static bool
18385 {
18390 {
18393 }
18397 }
18399 /* We're out of SFINAE context now, so generate diagnostics for the access
18400 errors we saw earlier when instantiating D from TMPL and ARGS. */
18402 static void
18404 {
18416 }
18418 /* Instantiate the indicated variable, function, or alias template TMPL with
18419 the template arguments in TARG_PTR. */
18421 static tree
18423 {
18425 tree fndecl;
18426 tree gen_tmpl;
18427 tree spec;
18435 /* If this function is a clone, handle it specially. */
18437 {
18438 tree spec;
18439 tree clone;
18441 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
18442 DECL_CLONED_FUNCTION. */
18448 /* Look for the clone. */
18452 /* We should always have found the clone by now. */
18455 }
18460 /* Check to see if we already have this specialization. */
18464 /* targ_ptr only has the innermost template args, so add the outer ones
18465 from tmpl, which could be either a partial instantiation or gen_tmpl (in
18466 the case of a non-dependent call within a template definition). */
18467 targ_ptr = (add_outermost_template_args
18469 targ_ptr));
18471 /* It would be nice to avoid hashing here and then again in tsubst_decl,
18472 but it doesn't seem to be on the hot path. */
18481 {
18483 {
18487 }
18489 }
18492 complain))
18495 /* We are building a FUNCTION_DECL, during which the access of its
18496 parameters and return types have to be checked. However this
18497 FUNCTION_DECL which is the desired context for access checking
18498 is not built yet. We solve this chicken-and-egg problem by
18499 deferring all checks until we have the FUNCTION_DECL. */
18502 /* Instantiation of the function happens in the context of the function
18503 template, not the context of the overload resolution we're doing. */
18505 /* If there are dependent arguments, e.g. because we're doing partial
18506 ordering, make sure processing_template_decl stays set. */
18510 {
18514 }
18520 {
18521 /* We need to determine if we're using a partial or explicit
18522 specialization now, because the type of the variable could be
18523 different. */
18529 {
18534 }
18535 }
18537 /* Substitute template parameters to obtain the specialization. */
18545 {
18548 }
18550 /* The DECL_TI_TEMPLATE should always be the immediate parent
18551 template, not the most general template. */
18555 /* Now we know the specialization, compute access previously
18556 deferred. Do no access control for inheriting constructors,
18557 as we already checked access for the inherited constructor. */
18560 {
18565 }
18568 /* If we've just instantiated the main entry point for a function,
18569 instantiate all the alternate entry points as well. We do this
18570 by cloning the instantiation of the main entry point, not by
18571 instantiating the template clones. */
18576 {
18578 {
18579 /* Remember to reinstantiate when we're out of SFINAE so the user
18580 can see the errors. */
18582 }
18584 }
18586 }
18588 /* Wrapper for instantiate_template_1. */
18590 tree
18592 {
18593 tree ret;
18598 }
18600 /* Instantiate the alias template TMPL with ARGS. Also push a template
18601 instantiation level, which instantiate_template doesn't do because
18602 functions and variables have sufficient context established by the
18603 callers. */
18605 static tree
18607 {
18614 {
18617 }
18619 args =
18627 /* We can't free this if a pending_template entry or last_error_tinst_level
18628 is pointing at it. */
18634 }
18636 /* PARM is a template parameter pack for FN. Returns true iff
18637 PARM is used in a deducible way in the argument list of FN. */
18639 static bool
18641 {
18644 {
18646 tree packs;
18652 {
18653 /* The template parameter pack is used in a function parameter
18654 pack. If this is the end of the parameter list, the
18655 template parameter pack is deducible. */
18658 else
18659 /* Otherwise, not. Well, it could be deduced from
18660 a non-pack parameter, but doing so would end up with
18661 a deduction mismatch, so don't bother. */
18663 }
18664 }
18665 /* The template parameter pack isn't used in any function parameter
18666 packs, but it might be used deeper, e.g. tuple<Args...>. */
18668 }
18670 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
18671 NARGS elements of the arguments that are being used when calling
18672 it. TARGS is a vector into which the deduced template arguments
18673 are placed.
18675 Returns either a FUNCTION_DECL for the matching specialization of FN or
18676 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
18677 true, diagnostics will be printed to explain why it failed.
18679 If FN is a conversion operator, or we are trying to produce a specific
18680 specialization, RETURN_TYPE is the return type desired.
18682 The EXPLICIT_TARGS are explicit template arguments provided via a
18683 template-id.
18685 The parameter STRICT is one of:
18687 DEDUCE_CALL:
18688 We are deducing arguments for a function call, as in
18689 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
18690 deducing arguments for a call to the result of a conversion
18691 function template, as in [over.call.object].
18693 DEDUCE_CONV:
18694 We are deducing arguments for a conversion function, as in
18695 [temp.deduct.conv].
18697 DEDUCE_EXACT:
18698 We are deducing arguments when doing an explicit instantiation
18699 as in [temp.explicit], when determining an explicit specialization
18700 as in [temp.expl.spec], or when taking the address of a function
18701 template, as in [temp.deduct.funcaddr]. */
18703 tree
18705 tree explicit_targs,
18706 tree targs,
18709 tree return_type,
18710 unification_kind_t strict,
18714 {
18715 tree parms;
18716 tree fntype;
18729 tree tinst;
18735 full_targs = (add_outermost_template_args
18737 targs));
18742 /* In C++0x, it's possible to have a function template whose type depends
18743 on itself recursively. This is most obvious with decltype, but can also
18744 occur with enumeration scope (c++/48969). So we need to catch infinite
18745 recursion and reject the substitution at deduction time; this function
18746 will return error_mark_node for any repeated substitution.
18748 This also catches excessive recursion such as when f<N> depends on
18749 f<N-1> across all integers, and returns error_mark_node for all the
18750 substitutions back up to the initial one.
18752 This is, of course, not reentrant. */
18762 {
18763 /* [temp.deduct]
18765 The specified template arguments must match the template
18766 parameters in kind (i.e., type, nontype, template), and there
18767 must not be more arguments than there are parameters;
18768 otherwise type deduction fails.
18770 Nontype arguments must match the types of the corresponding
18771 nontype template parameters, or must be convertible to the
18772 types of the corresponding nontype parameters as specified in
18773 _temp.arg.nontype_, otherwise type deduction fails.
18775 All references in the function type of the function template
18776 to the corresponding template parameters are replaced by the
18777 specified template argument values. If a substitution in a
18778 template parameter or in the function type of the function
18779 template results in an invalid type, type deduction fails. */
18790 explicit_targs);
18792 /* Adjust any explicit template arguments before entering the
18793 substitution context. */
18794 explicit_targs
18796 complain,
18802 /* Substitute the explicit args into the function type. This is
18803 necessary so that, for instance, explicitly declared function
18804 arguments can match null pointed constants. If we were given
18805 an incomplete set of explicit args, we must not do semantic
18806 processing during substitution as we could create partial
18807 instantiations. */
18809 {
18814 /* Dig out the actual parm. */
18817 {
18820 }
18822 {
18825 }
18828 /* No explicit argument for this template parameter. */
18832 {
18833 /* Mark the argument pack as "incomplete". We could
18834 still deduce more arguments during unification.
18835 We remove this mark in type_unification_real. */
18837 {
18841 }
18843 /* We have some incomplete argument packs. */
18845 }
18846 }
18850 {
18853 }
18856 /* Ignore any access checks; we'll see them again in
18857 instantiate_template and they might have the wrong
18858 access path at this point. */
18870 /* Place the explicitly specified arguments in TARGS. */
18874 }
18876 /* Never do unification on the 'this' parameter. */
18880 {
18881 /* We're deducing for a call to the result of a template conversion
18882 function. The parms we really want are in return_type. */
18886 }
18888 {
18897 }
18899 /* We allow incomplete unification without an error message here
18900 because the standard doesn't seem to explicitly prohibit it. Our
18901 callers must be ready to deal with unification failures in any
18902 event. */
18905 /* If we aren't explaining yet, push tinst context so we can see where
18906 any errors (e.g. from class instantiations triggered by instantiation
18907 of default template arguments) come from. If we are explaining, this
18908 context is redundant. */
18910 {
18913 }
18915 /* type_unification_real will pass back any access checks from default
18916 template argument substitution. */
18928 /* Now that we have bindings for all of the template arguments,
18929 ensure that the arguments deduced for the template template
18930 parameters have compatible template parameter lists. We cannot
18931 check this property before we have deduced all template
18932 arguments, because the template parameter types of a template
18933 template parameter might depend on prior template parameters
18934 deduced after the template template parameter. The following
18935 ill-formed example illustrates this issue:
18937 template<typename T, template<T> class C> void f(C<5>, T);
18939 template<int N> struct X {};
18941 void g() {
18942 f(X<5>(), 5l); // error: template argument deduction fails
18943 }
18945 The template parameter list of 'C' depends on the template type
18946 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
18947 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
18948 time that we deduce 'C'. */
18951 {
18954 }
18956 /* All is well so far. Now, check:
18958 [temp.deduct]
18960 When all template arguments have been deduced, all uses of
18961 template parameters in nondeduced contexts are replaced with
18962 the corresponding deduced argument values. If the
18963 substitution results in an invalid type, as described above,
18964 type deduction fails. */
18967 {
18970 }
18972 /* Also collect access checks from the instantiation. */
18985 /* Now perform any access checks encountered during substitution. */
18992 /* If we're looking for an exact match, check that what we got
18993 is indeed an exact match. It might not be if some template
18994 parameters are used in non-deduced contexts. But don't check
18995 for an exact match if we have dependent template arguments;
18996 in that case we're doing partial ordering, and we already know
18997 that we have two candidates that will provide the actual type. */
18999 {
19003 tree sarg
19009 {
19013 }
19014 }
19016 /* After doing deduction with the inherited constructor, actually return an
19017 instantiation of the inheriting constructor. */
19023 fail:
19026 {
19028 /* Reset once we're all the way out. */
19030 }
19032 /* We can't free this if a pending_template entry or last_error_tinst_level
19033 is pointing at it. */
19039 }
19041 /* Adjust types before performing type deduction, as described in
19042 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
19043 sections are symmetric. PARM is the type of a function parameter
19044 or the return type of the conversion function. ARG is the type of
19045 the argument passed to the call, or the type of the value
19046 initialized with the result of the conversion function.
19047 ARG_EXPR is the original argument expression, which may be null. */
19049 static int
19053 tree arg_expr)
19054 {
19058 {
19063 /* Swap PARM and ARG throughout the remainder of this
19064 function; the handling is precisely symmetric since PARM
19065 will initialize ARG rather than vice versa. */
19070 /* Core issue #873: Do the DR606 thing (see below) for these cases,
19071 too, but here handle it by stripping the reference from PARM
19072 rather than by adding it to ARG. */
19080 /* Nothing else to do in this case. */
19085 }
19088 {
19089 /* [temp.deduct.call]
19091 If P is not a reference type:
19093 --If A is an array type, the pointer type produced by the
19094 array-to-pointer standard conversion (_conv.array_) is
19095 used in place of A for type deduction; otherwise,
19097 --If A is a function type, the pointer type produced by
19098 the function-to-pointer standard conversion
19099 (_conv.func_) is used in place of A for type deduction;
19100 otherwise,
19102 --If A is a cv-qualified type, the top level
19103 cv-qualifiers of A's type are ignored for type
19104 deduction. */
19109 else
19111 }
19113 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
19114 reference to a cv-unqualified template parameter that does not represent a
19115 template parameter of a class template (during class template argument
19116 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
19117 an lvalue, the type "lvalue reference to A" is used in place of A for type
19118 deduction. */
19125 /* try_one_overload doesn't provide an arg_expr, but
19126 functions are always lvalues. */
19130 /* [temp.deduct.call]
19132 If P is a cv-qualified type, the top level cv-qualifiers
19133 of P's type are ignored for type deduction. If P is a
19134 reference type, the type referred to by P is used for
19135 type deduction. */
19138 {
19141 }
19143 /* DR 322. For conversion deduction, remove a reference type on parm
19144 too (which has been swapped into ARG). */
19149 }
19151 /* Subroutine of unify_one_argument. PARM is a function parameter of a
19152 template which does contain any deducible template parameters; check if
19153 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
19154 unify_one_argument. */
19156 static int
19159 {
19160 tree type;
19164 else
19171 {
19175 }
19177 {
19182 }
19186 else
19188 }
19192 /* Returns true iff the expression EXPR is one from which a template
19193 argument can be deduced. In other words, if it's an undecorated
19194 use of a template non-type parameter. */
19196 static bool
19198 {
19199 /* Strip implicit conversions. */
19203 }
19205 /* Returns true iff the array domain DOMAIN uses a template parameter in a
19206 deducible way; that is, if it has a max value of <PARM> - 1. */
19208 static bool
19210 {
19219 }
19221 /* Returns true iff the template arguments ARGS use a template parameter
19222 in a deducible way. */
19224 static bool
19226 {
19228 {
19233 else
19234 {
19241 else
19243 }
19246 }
19248 }
19250 /* Returns true iff TYPE contains any deducible references to template
19251 parameters, as per 14.8.2.5. */
19253 static bool
19255 {
19259 /* T
19260 cv-list T
19261 TT<T>
19262 TT<i>
19263 TT<> */
19268 /* T*
19269 T&
19270 T&& */
19274 /* T[integer-constant ]
19275 type [i] */
19280 /* T type ::*
19281 type T::*
19282 T T::*
19283 T (type ::*)()
19284 type (T::*)()
19285 type (type ::*)(T)
19286 type (T::*)(T)
19287 T (type ::*)(T)
19288 T (T::*)()
19289 T (T::*)(T) */
19292 || (uses_deducible_template_parms
19295 /* template-name <T> (where template-name refers to a class template)
19296 template-name <i> (where template-name refers to a class template) */
19303 /* type (T)
19304 T()
19305 T(T) */
19308 {
19317 }
19320 }
19322 /* Subroutine of type_unification_real and unify_pack_expansion to
19323 handle unification of a single P/A pair. Parameters are as
19324 for those functions. */
19326 static int
19330 {
19337 /* We can't deduce anything from this, but we might get all the
19338 template args from other function args. */
19341 /* Implicit conversions (Clause 4) will be performed on a function
19342 argument to convert it to the type of the corresponding function
19343 parameter if the parameter type contains no template-parameters that
19344 participate in template argument deduction. */
19347 /* For function parameters with no deducible template parameters,
19348 just return. We'll check non-dependent conversions later. */
19352 {
19354 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
19355 | UNIFY_ALLOW_MORE_CV_QUAL
19369 }
19371 /* We only do these transformations if this is the top-level
19372 parameter_type_list in a call or declaration matching; in other
19373 situations (nested function declarators, template argument lists) we
19374 won't be comparing a type to an expression, and we don't do any type
19375 adjustments. */
19377 {
19379 {
19382 {
19383 /* [temp.deduct.type] A template-argument can be
19384 deduced from a pointer to function or pointer
19385 to member function argument if the set of
19386 overloaded functions does not contain function
19387 templates and at most one of a set of
19388 overloaded functions provides a unique
19389 match. */
19393 /* If a unique match was not found, this is a
19394 non-deduced context, so we still succeed. */
19396 }
19402 }
19404 arg_strict |=
19406 }
19407 else
19412 /* For deduction from an init-list we need the actual list. */
19416 }
19418 /* for_each_template_parm callback that always returns 0. */
19420 static int
19422 {
19424 }
19426 /* for_each_template_parm any_fn callback to handle deduction of a template
19427 type argument from the type of an array bound. */
19429 static int
19431 {
19439 {
19445 }
19447 /* Keep walking. */
19449 }
19451 /* Try to deduce any not-yet-deduced template type arguments from the type of
19452 an array bound. This is handled separately from unify because 14.8.2.5 says
19453 "The type of a type parameter is only deduced from an array bound if it is
19454 not otherwise deduced." */
19456 static void
19458 {
19463 }
19465 /* Most parms like fn_type_unification.
19467 If SUBR is 1, we're being called recursively (to unify the
19468 arguments of a function or method parameter of a function
19469 template).
19471 CHECKS is a pointer to a vector of access checks encountered while
19472 substituting default template arguments. */
19474 static int
19476 tree full_targs,
19477 tree xparms,
19481 unification_kind_t strict,
19485 {
19490 tree parms;
19501 /* Reset the number of non-defaulted template arguments contained
19502 in TARGS. */
19505 again:
19513 {
19518 /* For a function parameter pack that occurs at the end of the
19519 parameter-declaration-list, the type A of each remaining
19520 argument of the call is compared with the type P of the
19521 declarator-id of the function parameter pack. */
19527 /* For a function parameter pack that does not occur at the
19528 end of the parameter-declaration-list, the type of the
19529 parameter pack is a non-deduced context. */
19536 explain_p))
19538 }
19543 {
19544 /* Unify the remaining arguments with the pack expansion type. */
19545 tree argvec;
19548 /* Allocate a TREE_VEC and copy in all of the arguments */
19553 /* Copy the parameter into parmvec. */
19559 /* Advance to the end of the list of parameters. */
19561 }
19563 /* Fail if we've reached the end of the parm list, and more args
19564 are present, and the parm list isn't variadic. */
19567 /* Fail if parms are left and they don't have default values and
19568 they aren't all deduced as empty packs (c++/57397). This is
19569 consistent with sufficient_parms_p. */
19572 {
19576 do
19577 {
19580 count++;
19582 }
19586 type_pack_p);
19587 }
19590 {
19591 tsubst_flags_t complain = (explain_p
19592 ? tf_warning_or_error
19597 {
19601 /* Clear the "incomplete" flags on all argument packs now so that
19602 substituting them into later default arguments works. */
19604 {
19607 }
19615 {
19620 }
19622 /* If this is an undeduced nontype parameter that depends on
19623 a type parameter, try another pass; its type may have been
19624 deduced from a later argument than the one from which
19625 this parameter can be deduced. */
19629 {
19632 }
19634 /* Core issue #226 (C++0x) [temp.deduct]:
19636 If a template argument has not been deduced, its
19637 default template argument, if any, is used.
19639 When we are in C++98 mode, TREE_PURPOSE will either
19640 be NULL_TREE or ERROR_MARK_NODE, so we do not need
19641 to explicitly check cxx_dialect here. */
19643 /* OK, there is a default argument. Wait until after the
19644 conversion check to do substitution. */
19647 /* If the type parameter is a parameter pack, then it will
19648 be deduced to an empty parameter pack. */
19650 {
19651 tree arg;
19654 {
19657 }
19658 else
19665 }
19668 }
19670 /* DR 1391: All parameters have args, now check non-dependent parms for
19671 convertibility. */
19675 {
19681 /* For a function parameter pack that occurs at the end of the
19682 parameter-declaration-list, the type A of each remaining
19683 argument of the call is compared with the type P of the
19684 declarator-id of the function parameter pack. */
19690 /* For a function parameter pack that does not occur at the
19691 end of the parameter-declaration-list, the type of the
19692 parameter pack is a non-deduced context. */
19701 explain_p))
19703 }
19705 /* Now substitute into the default template arguments. */
19707 {
19731 else
19739 {
19741 /* The position of the first default template argument,
19742 is also the number of non-defaulted arguments in TARGS.
19743 Record that. */
19746 }
19747 }
19751 }
19757 }
19759 /* Subroutine of type_unification_real. Args are like the variables
19760 at the call site. ARG is an overloaded function (or template-id);
19761 we try deducing template args from each of the overloads, and if
19762 only one succeeds, we go with that. Modifies TARGS and returns
19763 true on success. */
19765 static bool
19767 tree targs,
19768 tree parm,
19769 tree arg,
19770 unification_kind_t strict,
19773 {
19780 {
19783 }
19784 else
19788 /* Handle `&x' where `x' is some static or non-static member
19789 function name. */
19795 /* Strip baselink information. */
19800 {
19801 /* If we got some explicit template args, we need to plug them into
19802 the affected templates before we try to unify, in case the
19803 explicit args will completely resolve the templates in question. */
19810 {
19823 {
19828 {
19831 }
19832 }
19835 }
19836 /* If no templates (or more than one) are fully resolved by the
19837 explicit arguments, this template-id is a non-deduced context; it
19838 could still be OK if we deduce all template arguments for the
19839 enclosing call through other arguments. */
19842 }
19845 /* If ARG is, for example, "(0, &f)" then its type will be unknown
19846 -- but the deduction does not succeed because the expression is
19847 not just the function on its own. */
19849 else
19851 {
19856 {
19859 }
19860 }
19862 /* [temp.deduct.type] A template-argument can be deduced from a pointer
19863 to function or pointer to member function argument if the set of
19864 overloaded functions does not contain function templates and at most
19865 one of a set of overloaded functions provides a unique match.
19867 So if we found multiple possibilities, we return success but don't
19868 deduce anything. */
19871 {
19875 {
19880 /* Don't forget explicit template arguments in a pack. */
19884 }
19885 }
19890 }
19892 /* Core DR 115: In contexts where deduction is done and fails, or in
19893 contexts where deduction is not done, if a template argument list is
19894 specified and it, along with any default template arguments, identifies
19895 a single function template specialization, then the template-id is an
19896 lvalue for the function template specialization. */
19898 tree
19900 {
19913 {
19916 }
19918 {
19921 }
19923 {
19926 }
19929 {
19933 /* If we got some explicit template args, we need to plug them into
19934 the affected templates before we try to unify, in case the
19935 explicit args will completely resolve the templates in question. */
19943 {
19956 {
19959 {
19962 }
19964 {
19967 }
19968 }
19969 }
19971 {
19979 {
19980 tree base
19983 }
19987 }
19989 /* There were no good options and at least one bad one, so let the
19990 user know what the problem is. */
19992 }
19994 }
19996 /* Subroutine of resolve_overloaded_unification; does deduction for a single
19997 overload. Fills TARGS with any deduced arguments, or error_mark_node if
19998 different overloads deduce different arguments for a given parm.
19999 ADDR_P is true if the expression for which deduction is being
20000 performed was of the form "& fn" rather than simply "fn".
20002 Returns 1 on success. */
20004 static int
20006 tree orig_targs,
20007 tree targs,
20008 tree parm,
20009 tree arg,
20010 unification_kind_t strict,
20014 {
20016 tree tempargs;
20022 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20023 to function or pointer to member function argument if the set of
20024 overloaded functions does not contain function templates and at most
20025 one of a set of overloaded functions provides a unique match.
20027 So if this is a template, just return success. */
20039 /* We don't copy orig_targs for this because if we have already deduced
20040 some template args from previous args, unify would complain when we
20041 try to deduce a template parameter for the same argument, even though
20042 there isn't really a conflict. */
20049 /* First make sure we didn't deduce anything that conflicts with
20050 explicitly specified args. */
20052 {
20059 /* Since we're unifying against ourselves, we will fill in
20060 template args used in the function parm list with our own
20061 template parms. Discard them. */
20064 {
20065 /* Check that the argument at each index of the deduced argument pack
20066 is equivalent to the corresponding explicitly specified argument.
20067 We may have deduced more arguments than were explicitly specified,
20068 and that's OK. */
20070 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
20071 that's wrong if we deduce the same argument pack from multiple
20072 function arguments: it's only incomplete the first time. */
20085 }
20088 }
20091 {
20096 }
20099 }
20101 /* PARM is a template class (perhaps with unbound template
20102 parameters). ARG is a fully instantiated type. If ARG can be
20103 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
20104 TARGS are as for unify. */
20106 static tree
20109 {
20110 tree copy_of_targs;
20120 /* We need to make a new template argument vector for the call to
20121 unify. If we used TARGS, we'd clutter it up with the result of
20122 the attempted unification, even if this class didn't work out.
20123 We also don't want to commit ourselves to all the unifications
20124 we've already done, since unification is supposed to be done on
20125 an argument-by-argument basis. In other words, consider the
20126 following pathological case:
20128 template <int I, int J, int K>
20129 struct S {};
20131 template <int I, int J>
20132 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
20134 template <int I, int J, int K>
20135 void f(S<I, J, K>, S<I, I, I>);
20137 void g() {
20138 S<0, 0, 0> s0;
20139 S<0, 1, 2> s2;
20141 f(s0, s2);
20142 }
20144 Now, by the time we consider the unification involving `s2', we
20145 already know that we must have `f<0, 0, 0>'. But, even though
20146 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
20147 because there are two ways to unify base classes of S<0, 1, 2>
20148 with S<I, I, I>. If we kept the already deduced knowledge, we
20149 would reject the possibility I=1. */
20153 {
20157 }
20159 /* If unification failed, we're done. */
20165 }
20167 /* Given a template type PARM and a class type ARG, find the unique
20168 base type in ARG that is an instance of PARM. We do not examine
20169 ARG itself; only its base-classes. If there is not exactly one
20170 appropriate base class, return NULL_TREE. PARM may be the type of
20171 a partial specialization, as well as a plain template type. Used
20172 by unify. */
20174 static enum template_base_result
20177 {
20179 tree binfo;
20185 {
20186 /* The type could not be completed. */
20189 }
20191 /* Walk in inheritance graph order. The search order is not
20192 important, and this avoids multiple walks of virtual bases. */
20194 {
20199 {
20200 /* If there is more than one satisfactory baseclass, then:
20202 [temp.deduct.call]
20204 If they yield more than one possible deduced A, the type
20205 deduction fails.
20207 applies. */
20209 {
20212 }
20215 }
20216 }
20220 }
20222 /* Returns the level of DECL, which declares a template parameter. */
20224 static int
20226 {
20228 {
20238 }
20240 }
20242 /* Decide whether ARG can be unified with PARM, considering only the
20243 cv-qualifiers of each type, given STRICT as documented for unify.
20244 Returns nonzero iff the unification is OK on that basis. */
20246 static int
20248 {
20254 {
20255 /* Although a CVR qualifier is ignored when being applied to a
20256 substituted template parameter ([8.3.2]/1 for example), that
20257 does not allow us to unify "const T" with "int&" because both
20258 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
20259 It is ok when we're allowing additional CV qualifiers
20260 at the outer level [14.8.2.1]/3,1st bullet. */
20270 }
20281 }
20283 /* Determines the LEVEL and INDEX for the template parameter PARM. */
20284 void
20286 {
20290 {
20293 }
20294 else
20295 {
20298 }
20299 }
20301 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
20302 do { \
20303 if (unify (TP, TA, P, A, S, EP)) \
20304 return 1; \
20305 } while (0)
20307 /* Unifies the remaining arguments in PACKED_ARGS with the pack
20308 expansion at the end of PACKED_PARMS. Returns 0 if the type
20309 deduction succeeds, 1 otherwise. STRICT is the same as in
20310 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
20311 function call argument list. We'll need to adjust the arguments to make them
20312 types. SUBR tells us if this is from a recursive call to
20313 type_unification_real, or for comparing two template argument
20314 lists. */
20316 static int
20320 {
20321 tree parm
20327 /* Add in any args remembered from an earlier partial instantiation. */
20334 /* Determine the parameter packs we will be deducing from the
20335 pattern, and record their current deductions. */
20338 {
20342 /* Determine the index and level of this parameter pack. */
20345 /* Keep track of the parameter packs and their corresponding
20346 argument packs. */
20349 }
20351 /* Loop through all of the arguments that have not yet been
20352 unified and unify each with the pattern. */
20354 {
20355 tree parm;
20359 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
20360 or the element of its argument pack at the current index if
20361 this argument was explicitly specified. */
20363 {
20372 {
20375 }
20377 }
20379 /* If we had explicit template arguments, substitute them into the
20380 pattern before deduction. */
20382 {
20383 /* Some arguments might still be unspecified or dependent. */
20391 NULL_TREE);
20396 }
20397 else
20400 /* Unify the pattern with the current argument. */
20402 explain_p))
20405 /* For each parameter pack, collect the deduced value. */
20407 {
20413 }
20414 }
20416 /* Verify that the results of unification with the parameter packs
20417 produce results consistent with what we've seen before, and make
20418 the deduced argument packs available. */
20420 {
20427 /* By default keep the original deduced argument pack.
20428 If necessary, more specific code is going to update the
20429 resulting deduced argument later down in this function. */
20433 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
20434 actually deduce anything. */
20442 {
20443 /* If we had fewer function args than explicit template args,
20444 just use the explicits. */
20449 }
20452 {
20453 tree result;
20454 /* Build the deduced *_ARGUMENT_PACK. */
20456 {
20459 }
20460 else
20465 /* Note the deduced argument packs for this parameter
20466 pack. */
20468 }
20472 {
20473 /* We only had the explicitly-provided arguments before, but
20474 now we have a complete set of arguments. */
20480 }
20481 else
20482 {
20488 /* Inconsistent unification of this parameter pack. */
20490 bad_old_arg,
20491 bad_new_arg);
20492 }
20493 }
20496 }
20498 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
20499 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
20500 parameters and return value are as for unify. */
20502 static int
20506 {
20507 tree parm_max;
20508 tree arg_max;
20512 /* Our representation of array types uses "N - 1" as the
20513 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
20514 not an integer constant. We cannot unify arbitrarily
20515 complex expressions, so we eliminate the MINUS_EXPRs
20516 here. */
20520 {
20523 }
20527 {
20528 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
20529 trying to unify the type of a variable with the type
20530 of a template parameter. For example:
20532 template <unsigned int N>
20533 void f (char (&) [N]);
20534 int g();
20535 void h(int i) {
20536 char a[g(i)];
20537 f(a);
20538 }
20540 Here, the type of the ARG will be "int [g(i)]", and
20541 may be a SAVE_EXPR, etc. */
20545 }
20547 /* If only one of the bounds used a MINUS_EXPR, compensate
20548 by adding one to the other bound. */
20551 integer_type_node,
20552 parm_max,
20553 integer_one_node);
20556 integer_type_node,
20557 arg_max,
20558 integer_one_node);
20562 }
20564 /* Returns whether T, a P or A in unify, is a type, template or expression. */
20568 static pa_kind_t
20570 {
20579 else
20581 }
20583 /* Deduce the value of template parameters. TPARMS is the (innermost)
20584 set of template parameters to a template. TARGS is the bindings
20585 for those template parameters, as determined thus far; TARGS may
20586 include template arguments for outer levels of template parameters
20587 as well. PARM is a parameter to a template function, or a
20588 subcomponent of that parameter; ARG is the corresponding argument.
20589 This function attempts to match PARM with ARG in a manner
20590 consistent with the existing assignments in TARGS. If more values
20591 are deduced, then TARGS is updated.
20593 Returns 0 if the type deduction succeeds, 1 otherwise. The
20594 parameter STRICT is a bitwise or of the following flags:
20596 UNIFY_ALLOW_NONE:
20597 Require an exact match between PARM and ARG.
20598 UNIFY_ALLOW_MORE_CV_QUAL:
20599 Allow the deduced ARG to be more cv-qualified (by qualification
20600 conversion) than ARG.
20601 UNIFY_ALLOW_LESS_CV_QUAL:
20602 Allow the deduced ARG to be less cv-qualified than ARG.
20603 UNIFY_ALLOW_DERIVED:
20604 Allow the deduced ARG to be a template base class of ARG,
20605 or a pointer to a template base class of the type pointed to by
20606 ARG.
20607 UNIFY_ALLOW_INTEGER:
20608 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
20609 case for more information.
20610 UNIFY_ALLOW_OUTER_LEVEL:
20611 This is the outermost level of a deduction. Used to determine validity
20612 of qualification conversions. A valid qualification conversion must
20613 have const qualified pointers leading up to the inner type which
20614 requires additional CV quals, except at the outer level, where const
20615 is not required [conv.qual]. It would be normal to set this flag in
20616 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
20617 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
20618 This is the outermost level of a deduction, and PARM can be more CV
20619 qualified at this point.
20620 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
20621 This is the outermost level of a deduction, and PARM can be less CV
20622 qualified at this point. */
20624 static int
20627 {
20629 tree targ;
20630 tree tparm;
20632 tsubst_flags_t complain = (explain_p
20633 ? tf_warning_or_error
20636 /* I don't think this will do the right thing with respect to types.
20637 But the only case I've seen it in so far has been array bounds, where
20638 signedness is the only information lost, and I think that will be
20639 okay. */
20647 /* We can't deduce anything from this, but we might get all the
20648 template args from other function args. */
20654 /* If PARM uses template parameters, then we can't bail out here,
20655 even if ARG == PARM, since we won't record unifications for the
20656 template parameters. We might need them if we're trying to
20657 figure out which of two things is more specialized. */
20661 /* Handle init lists early, so the rest of the function can assume
20662 we're dealing with a type. */
20664 {
20669 /* Replace T with std::initializer_list<T> for deduction. */
20676 /* We can only deduce from an initializer list argument if the
20677 parameter is std::initializer_list or an array; otherwise this
20678 is a non-deduced context. */
20683 else
20684 {
20686 /* Deduction is defined in terms of a single type, so just punt
20687 on the (bizarre) std::initializer_list<T...>. */
20690 }
20693 {
20700 {
20704 /* It should only be possible to get here for a call. */
20706 elt_strict |= maybe_adjust_types_for_deduction
20709 }
20712 explain_p);
20713 }
20717 {
20718 /* Also deduce from the length of the initializer list. */
20725 }
20727 /* If the std::initializer_list<T> deduction worked, replace the
20728 deduced A with std::initializer_list<A>. */
20730 {
20735 }
20737 }
20739 /* If parm and arg aren't the same kind of thing (template, type, or
20740 expression), fail early. */
20744 /* Immediately reject some pairs that won't unify because of
20745 cv-qualification mismatches. */
20748 /* It is the elements of the array which hold the cv quals of an array
20749 type, and the elements might be template type parms. We'll check
20750 when we recurse. */
20752 /* We check the cv-qualifiers when unifying with template type
20753 parameters below. We want to allow ARG `const T' to unify with
20754 PARM `T' for example, when computing which of two templates
20755 is more specialized, for example. */
20769 {
20773 /* In a type which contains a nested-name-specifier, template
20774 argument values cannot be deduced for template parameters used
20775 within the nested-name-specifier. */
20787 /* The PARM is not one we're trying to unify. Just check
20788 to see if it matches ARG. */
20789 {
20794 else
20796 }
20803 /* Check for mixed types and values. */
20811 {
20814 {
20815 /* First try to match ARG directly. */
20817 explain_p);
20819 {
20820 /* Otherwise, look for a suitable base of ARG, as below. */
20827 }
20828 }
20829 /* ARG must be constructed from a template class or a template
20830 template parameter. */
20835 /* Deduce arguments T, i from TT<T> or TT<i>. */
20841 /* Fall through to deduce template name. */
20842 }
20846 {
20847 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
20849 /* Simple cases: Value already set, does match or doesn't. */
20854 }
20855 else
20856 {
20857 /* If PARM is `const T' and ARG is only `int', we don't have
20858 a match unless we are allowing additional qualification.
20859 If ARG is `const int' and PARM is just `T' that's OK;
20860 that binds `const int' to `T'. */
20865 /* Consider the case where ARG is `const volatile int' and
20866 PARM is `const T'. Then, T should be `volatile int'. */
20867 arg = cp_build_qualified_type_real
20872 /* Simple cases: Value already set, does match or doesn't. */
20878 /* Make sure that ARG is not a variable-sized array. (Note
20879 that were talking about variable-sized arrays (like
20880 `int[n]'), rather than arrays of unknown size (like
20881 `int[]').) We'll get very confused by such a type since
20882 the bound of the array is not constant, and therefore
20883 not mangleable. Besides, such types are not allowed in
20884 ISO C++, so we can do as we please here. We do allow
20885 them for 'auto' deduction, since that isn't ABI-exposed. */
20889 /* Strip typedefs as in convert_template_argument. */
20891 }
20893 /* If ARG is a parameter pack or an expansion, we cannot unify
20894 against it unless PARM is also a parameter pack. */
20899 /* If the argument deduction results is a METHOD_TYPE,
20900 then there is a problem.
20901 METHOD_TYPE doesn't map to any real C++ type the result of
20902 the deduction can not be of that type. */
20916 {
20917 /* The PARM is not one we're trying to unify. Just check
20918 to see if it matches ARG. */
20924 }
20930 {
20934 /* We're deducing from an array bound, the type doesn't matter. */
20940 }
20942 /* [temp.deduct.type] If, in the declaration of a function template
20943 with a non-type template-parameter, the non-type
20944 template-parameter is used in an expression in the function
20945 parameter-list and, if the corresponding template-argument is
20946 deduced, the template-argument type shall match the type of the
20947 template-parameter exactly, except that a template-argument
20948 deduced from an array bound may be of any integral type.
20949 The non-type parameter might use already deduced type parameters. */
20952 {
20956 }
20959 /* Template-parameter dependent expression. Just accept it for now.
20960 It will later be processed in convert_template_argument. */
20961 ;
20967 /* Convert the ARG to the type of PARM; the deduced non-type
20968 template argument must exactly match the types of the
20969 corresponding parameter. */
20972 {
20973 /* We haven't deduced the type of this parameter yet. */
20975 /* We deduce from array bounds in try_array_deduction. */
20977 {
20978 /* Deduce it from the non-type argument. */
20983 }
20984 else
20985 /* Try again later. */
20987 }
20988 else
20991 /* If ARG is a parameter pack or an expansion, we cannot unify
20992 against it unless PARM is also a parameter pack. */
20997 {
21000 }
21005 {
21006 /* A pointer-to-member constant can be unified only with
21007 another constant. */
21011 /* Just unify the class member. It would be useless (and possibly
21012 wrong, depending on the strict flags) to unify also
21013 PTRMEM_CST_CLASS, because we want to be sure that both parm and
21014 arg refer to the same variable, even if through different
21015 classes. For instance:
21017 struct A { int x; };
21018 struct B : A { };
21020 Unification of &A::x and &B::x must succeed. */
21023 }
21026 {
21030 /* [temp.deduct.call]
21032 A can be another pointer or pointer to member type that can
21033 be converted to the deduced A via a qualification
21034 conversion (_conv.qual_).
21036 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
21037 This will allow for additional cv-qualification of the
21038 pointed-to types if appropriate. */
21041 /* The derived-to-base conversion only persists through one
21042 level of pointers. */
21047 }
21079 /* We have already checked cv-qualification at the top of the
21080 function. */
21084 /* As far as unification is concerned, this wins. Later checks
21085 will invalidate it if necessary. */
21088 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
21089 /* Type INTEGER_CST can come from ordinary constant template args. */
21101 {
21111 /* Check for pack expansions in the parameters. */
21113 {
21115 {
21117 /* We can unify against something with a trailing
21118 parameter pack. */
21120 else
21121 /* [temp.deduct.type]/9: If the template argument list of
21122 P contains a pack expansion that is not the last
21123 template argument, the entire template argument list
21124 is a non-deduced context. */
21126 }
21127 }
21129 /* If we don't have enough arguments to satisfy the parameters
21130 (not counting the pack expression at the end), or we have
21131 too many arguments for a parameter list that doesn't end in
21132 a pack expression, we can't unify. */
21138 /* Unify all of the parameters that precede the (optional)
21139 pack expression. */
21141 {
21146 }
21149 DEDUCE_EXACT,
21152 }
21160 {
21168 }
21173 {
21177 {
21178 /* First, we try to unify the PARM and ARG directly. */
21183 {
21184 /* Fallback to the special case allowed in
21185 [temp.deduct.call]:
21187 If P is a class, and P has the form
21188 template-id, then A can be a derived class of
21189 the deduced A. Likewise, if P is a pointer to
21190 a class of the form template-id, A can be a
21191 pointer to a derived class pointed to by the
21192 deduced A. */
21198 {
21199 /* Don't give the derived diagnostic if we're
21200 already dealing with the same template. */
21201 bool same_template
21207 }
21208 }
21209 }
21213 /* Perhaps PARM is something like S<U> and ARG is S<int>.
21214 Then, we should unify `int' and `U'. */
21216 else
21217 /* There's no chance of unification succeeding. */
21222 }
21229 {
21232 tree a;
21238 /* CV qualifications for methods can never be deduced, they must
21239 match exactly. We need to check them explicitly here,
21240 because type_unification_real treats them as any other
21241 cv-qualified parameter. */
21243 && (!check_cv_quals_for_unify
21271 {
21283 }
21286 }
21289 /* Unify a pointer to member with a pointer to member function, which
21290 deduces the type of the member as a function type. */
21292 {
21293 /* Check top-level cv qualifiers */
21301 /* Determine the type of the function we are unifying against. */
21305 }
21324 /* Matched cases are handled by the ARG == PARM test above. */
21328 /* We might get a variable as a non-type template argument in parm if the
21329 corresponding parameter is type-dependent. Make any necessary
21330 adjustments based on whether arg is a reference. */
21334 {
21339 }
21340 /* Now use the normal expression code to check whether they match. */
21351 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
21352 or UNDERLYING_TYPE nodes. */
21356 /* Unification fails if we hit an error node. */
21361 {
21371 }
21372 /* FALLTHRU */
21375 /* An unresolved overload is a nondeduced context. */
21379 expr:
21380 /* We must be looking at an expression. This can happen with
21381 something like:
21383 template <int I>
21384 void foo(S<I>, S<I + 2>);
21386 This is a "nondeduced context":
21388 [deduct.type]
21390 The nondeduced contexts are:
21392 --A type that is a template-id in which one or more of
21393 the template-arguments is an expression that references
21394 a template-parameter.
21396 In these cases, we assume deduction succeeded, but don't
21397 actually infer any unifications. */
21402 else
21404 }
21405 }
21406 #undef RECUR_AND_CHECK_FAILURE
21407 \f
21408 /* Note that DECL can be defined in this translation unit, if
21409 required. */
21411 static void
21413 {
21414 tree clone;
21418 }
21420 /* Called if RESULT is explicitly instantiated, or is a member of an
21421 explicitly instantiated class. */
21423 void
21425 {
21428 /* If this entity has already been written out, it's too late to
21429 make any modifications. */
21433 /* For anonymous namespace we don't need to do anything. */
21435 {
21438 }
21441 /* The TREE_PUBLIC flag for function declarations will have been
21442 set correctly by tsubst. */
21445 /* This might have been set by an earlier implicit instantiation. */
21450 else
21451 {
21454 /* Always make artificials weak. */
21457 /* For WIN32 we also want to put explicit instantiations in
21458 linkonce sections. */
21461 }
21463 /* If EXTERN_P, then this function will not be emitted -- unless
21464 followed by an explicit instantiation, at which point its linkage
21465 will be adjusted. If !EXTERN_P, then this function will be
21466 emitted here. In neither circumstance do we want
21467 import_export_decl to adjust the linkage. */
21469 }
21471 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
21472 important template arguments. If any are missing, we check whether
21473 they're important by using error_mark_node for substituting into any
21474 args that were used for partial ordering (the ones between ARGS and END)
21475 and seeing if it bubbles up. */
21477 static bool
21479 {
21484 {
21487 }
21489 {
21493 }
21495 }
21497 /* Given two function templates PAT1 and PAT2, return:
21499 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
21500 -1 if PAT2 is more specialized than PAT1.
21501 0 if neither is more specialized.
21503 LEN indicates the number of parameters we should consider
21504 (defaulted parameters should not be considered).
21506 The 1998 std underspecified function template partial ordering, and
21507 DR214 addresses the issue. We take pairs of arguments, one from
21508 each of the templates, and deduce them against each other. One of
21509 the templates will be more specialized if all the *other*
21510 template's arguments deduce against its arguments and at least one
21511 of its arguments *does* *not* deduce against the other template's
21512 corresponding argument. Deduction is done as for class templates.
21513 The arguments used in deduction have reference and top level cv
21514 qualifiers removed. Iff both arguments were originally reference
21515 types *and* deduction succeeds in both directions, an lvalue reference
21516 wins against an rvalue reference and otherwise the template
21517 with the more cv-qualified argument wins for that pairing (if
21518 neither is more cv-qualified, they both are equal). Unlike regular
21519 deduction, after all the arguments have been deduced in this way,
21520 we do *not* verify the deduced template argument values can be
21521 substituted into non-deduced contexts.
21523 The logic can be a bit confusing here, because we look at deduce1 and
21524 targs1 to see if pat2 is at least as specialized, and vice versa; if we
21525 can find template arguments for pat1 to make arg1 look like arg2, that
21526 means that arg2 is at least as specialized as arg1. */
21528 int
21530 {
21543 /* Remove the this parameter from non-static member functions. If
21544 one is a non-static member function and the other is not a static
21545 member function, remove the first parameter from that function
21546 also. This situation occurs for operator functions where we
21547 locate both a member function (with this pointer) and non-member
21548 operator (with explicit first operand). */
21550 {
21555 }
21557 {
21560 {
21561 len--;
21563 }
21564 }
21566 /* If only one is a conversion operator, they are unordered. */
21570 /* Consider the return type for a conversion function */
21572 {
21575 len++;
21576 }
21578 processing_template_decl++;
21584 /* Stop when an ellipsis is seen. */
21586 {
21597 {
21598 /* When both arguments are pack expansions, we need only
21599 unify the patterns themselves. */
21603 /* This is the last comparison we need to do. */
21605 }
21607 /* DR 1847: If a particular P contains no template-parameters that
21608 participate in template argument deduction, that P is not used to
21609 determine the ordering. */
21615 {
21619 }
21622 {
21626 }
21632 {
21638 /* Setup the parameter vector, which contains only ARG1. */
21641 /* Setup the argument vector, which contains the remaining
21642 arguments. */
21651 /* We cannot deduce in the other direction, because ARG1 is
21652 a pack expansion but ARG2 is not. */
21654 }
21656 {
21662 /* Setup the parameter vector, which contains only ARG1. */
21665 /* Setup the argument vector, which contains the remaining
21666 arguments. */
21675 /* We cannot deduce in the other direction, because ARG2 is
21676 a pack expansion but ARG1 is not.*/
21678 }
21680 else
21681 {
21682 /* The normal case, where neither argument is a pack
21683 expansion. */
21690 }
21692 /* If we couldn't deduce arguments for tparms1 to make arg1 match
21693 arg2, then arg2 is not as specialized as arg1. */
21699 /* "If, for a given type, deduction succeeds in both directions
21700 (i.e., the types are identical after the transformations above)
21701 and both P and A were reference types (before being replaced with
21702 the type referred to above):
21703 - if the type from the argument template was an lvalue reference and
21704 the type from the parameter template was not, the argument type is
21705 considered to be more specialized than the other; otherwise,
21706 - if the type from the argument template is more cv-qualified
21707 than the type from the parameter template (as described above),
21708 the argument type is considered to be more specialized than the other;
21709 otherwise,
21710 - neither type is more specialized than the other." */
21713 {
21715 {
21718 else
21720 }
21722 {
21727 }
21728 }
21731 /* We've failed to deduce something in either direction.
21732 These must be unordered. */
21735 next:
21739 /* We have already processed all of the arguments in our
21740 handing of the pack expansion type. */
21745 }
21747 /* "In most cases, all template parameters must have values in order for
21748 deduction to succeed, but for partial ordering purposes a template
21749 parameter may remain without a value provided it is not used in the
21750 types being used for partial ordering."
21752 Thus, if we are missing any of the targs1 we need to substitute into
21753 origs1, then pat2 is not as specialized as pat1. This can happen when
21754 there is a nondeduced context. */
21760 processing_template_decl--;
21762 /* If both deductions succeed, the partial ordering selects the more
21763 constrained template. */
21765 {
21770 }
21772 /* All things being equal, if the next argument is a pack expansion
21773 for one function but not for the other, prefer the
21774 non-variadic function. FIXME this is bogus; see c++/41958. */
21778 {
21781 }
21787 else
21789 }
21791 /* Determine which of two partial specializations of TMPL is more
21792 specialized.
21794 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
21795 to the first partial specialization. The TREE_PURPOSE is the
21796 innermost set of template parameters for the partial
21797 specialization. PAT2 is similar, but for the second template.
21799 Return 1 if the first partial specialization is more specialized;
21800 -1 if the second is more specialized; 0 if neither is more
21801 specialized.
21803 See [temp.class.order] for information about determining which of
21804 two templates is more specialized. */
21806 static int
21808 {
21809 tree targs;
21818 /* Just like what happens for functions, if we are ordering between
21819 different template specializations, we may encounter dependent
21820 types in the arguments, and we need our dependency check functions
21821 to behave correctly. */
21825 {
21828 }
21832 {
21835 }
21838 /* If both deductions succeed, the partial ordering selects the more
21839 constrained template. */
21843 /* In the case of a tie where at least one of the templates
21844 has a parameter pack at the end, the template with the most
21845 non-packed parameters wins. */
21847 && any_deductions
21850 {
21856 /* We don't count the pack expansion at the end. */
21866 }
21869 }
21871 /* Return the template arguments that will produce the function signature
21872 DECL from the function template FN, with the explicit template
21873 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
21874 also match. Return NULL_TREE if no satisfactory arguments could be
21875 found. */
21877 static tree
21879 {
21883 tree decl_arg_types;
21886 tree arg;
21890 /* Never do unification on the 'this' parameter. */
21911 }
21913 /* Return the innermost template arguments that, when applied to a partial
21914 specialization SPEC_TMPL of TMPL, yield the ARGS.
21916 For example, suppose we have:
21918 template <class T, class U> struct S {};
21919 template <class T> struct S<T*, int> {};
21921 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
21922 partial specialization and the ARGS will be {double*, int}. The resulting
21923 vector will be {double}, indicating that `T' is bound to `double'. */
21925 static tree
21927 {
21929 tree spec_args
21932 tree deduced_args;
21933 tree innermost_deduced_args;
21937 {
21941 innermost_deduced_args);
21942 }
21943 else
21947 again:
21956 {
21958 {
21964 }
21966 }
21970 {
21973 }
21975 /* Verify that nondeduced template arguments agree with the type
21976 obtained from argument deduction.
21978 For example:
21980 struct A { typedef int X; };
21981 template <class T, class U> struct C {};
21982 template <class T> struct C<T, typename T::X> {};
21984 Then with the instantiation `C<A, int>', we can deduce that
21985 `T' is `A' but unify () does not check whether `typename T::X'
21986 is `int'. */
21997 /* We only need to check the innermost arguments; the other
21998 arguments will always agree. */
22003 /* Now that we have bindings for all of the template arguments,
22004 ensure that the arguments deduced for the template template
22005 parameters have compatible template parameter lists. See the use
22006 of template_template_parm_bindings_ok_p in fn_type_unification
22007 for more information. */
22012 }
22014 // Compare two function templates T1 and T2 by deducing bindings
22015 // from one against the other. If both deductions succeed, compare
22016 // constraints to see which is more constrained.
22017 static int
22019 {
22024 {
22027 }
22030 {
22033 }
22035 // If both deductions succeed, then one may be more constrained.
22040 }
22042 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
22043 Return the TREE_LIST node with the most specialized template, if
22044 any. If there is no most specialized template, the error_mark_node
22045 is returned.
22047 Note that this function does not look at, or modify, the
22048 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
22049 returned is one of the elements of INSTANTIATIONS, callers may
22050 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
22051 and retrieve it from the value returned. */
22053 tree
22055 {
22062 {
22068 {
22069 /* Equally specialized, move to next function. If there
22070 is no next function, nothing's most specialized. */
22075 }
22076 }
22079 /* Now verify that champ is better than everything earlier in the
22080 instantiation list. */
22083 {
22086 }
22087 }
22089 processing_template_decl--;
22095 }
22097 /* If DECL is a specialization of some template, return the most
22098 general such template. Otherwise, returns NULL_TREE.
22100 For example, given:
22102 template <class T> struct S { template <class U> void f(U); };
22104 if TMPL is `template <class U> void S<int>::f(U)' this will return
22105 the full template. This function will not trace past partial
22106 specializations, however. For example, given in addition:
22108 template <class T> struct S<T*> { template <class U> void f(U); };
22110 if TMPL is `template <class U> void S<int*>::f(U)' this will return
22111 `template <class T> template <class U> S<T*>::f(U)'. */
22113 tree
22115 {
22117 {
22120 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
22121 template friend, or a FIELD_DECL for a capture pack. */
22124 }
22126 /* Look for more and more general templates. */
22128 {
22129 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
22130 (See cp-tree.h for details.) */
22139 /* Stop if we run into an explicitly specialized class template. */
22146 }
22149 }
22151 /* Return the most specialized of the template partial specializations
22152 which can produce TARGET, a specialization of some class or variable
22153 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
22154 a TEMPLATE_DECL node corresponding to the partial specialization, while
22155 the TREE_PURPOSE is the set of template arguments that must be
22156 substituted into the template pattern in order to generate TARGET.
22158 If the choice of partial specialization is ambiguous, a diagnostic
22159 is issued, and the error_mark_node is returned. If there are no
22160 partial specializations matching TARGET, then NULL_TREE is
22161 returned, indicating that the primary template should be used. */
22163 static tree
22165 {
22167 tree t;
22168 tree champ;
22175 {
22179 }
22181 {
22184 }
22186 {
22190 }
22191 else
22196 /* For determining which partial specialization to use, only the
22197 innermost args are interesting. */
22199 {
22202 }
22205 {
22206 tree spec_args;
22210 {
22211 /* Substitute in the template args from the enclosing class. */
22215 }
22222 {
22226 /* Keep the candidate only if the constraints are satisfied,
22227 or if we're not compiling with concepts. */
22230 {
22233 }
22234 }
22235 }
22245 {
22248 ;
22249 else
22250 {
22252 {
22255 {
22258 }
22259 }
22261 }
22262 }
22266 {
22269 {
22272 }
22273 }
22276 {
22283 else
22287 {
22292 }
22295 }
22298 }
22300 /* Explicitly instantiate DECL. */
22302 void
22304 {
22309 /* An error occurred, for which grokdeclarator has already issued
22310 an appropriate message. */
22313 {
22316 }
22322 {
22323 /* There is an asymmetry here in the way VAR_DECLs and
22324 FUNCTION_DECLs are handled by grokdeclarator. In the case of
22325 the latter, the DECL we get back will be marked as a
22326 template instantiation, and the appropriate
22327 DECL_TEMPLATE_INFO will be set up. This does not happen for
22328 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
22329 should handle VAR_DECLs as it currently handles
22330 FUNCTION_DECLs. */
22332 {
22335 }
22338 {
22341 }
22343 {
22348 }
22349 }
22351 {
22354 }
22355 else
22358 /* Check for various error cases. Note that if the explicit
22359 instantiation is valid the RESULT will currently be marked as an
22360 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
22361 until we get here. */
22364 {
22365 /* DR 259 [temp.spec].
22367 Both an explicit instantiation and a declaration of an explicit
22368 specialization shall not appear in a program unless the explicit
22369 instantiation follows a declaration of the explicit specialization.
22371 For a given set of template parameters, if an explicit
22372 instantiation of a template appears after a declaration of an
22373 explicit specialization for that template, the explicit
22374 instantiation has no effect. */
22376 }
22378 {
22379 /* [temp.spec]
22381 No program shall explicitly instantiate any template more
22382 than once.
22384 We check DECL_NOT_REALLY_EXTERN so as not to complain when
22385 the first instantiation was `extern' and the second is not,
22386 and EXTERN_P for the opposite case. */
22389 /* If an "extern" explicit instantiation follows an ordinary
22390 explicit instantiation, the template is instantiated. */
22393 }
22395 {
22398 }
22400 {
22403 }
22406 ;
22408 {
22411 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
22414 }
22415 else
22423 }
22425 static void
22427 {
22433 {
22436 }
22437 }
22439 /* Called from do_type_instantiation through binding_table_foreach to
22440 do recursive instantiation for the type bound in ENTRY. */
22441 static void
22443 {
22449 }
22451 /* Perform an explicit instantiation of template class T. STORAGE, if
22452 non-null, is the RID for extern, inline or static. COMPLAIN is
22453 nonzero if this is called from the parser, zero if called recursively,
22454 since the standard is unclear (as detailed below). */
22456 void
22458 {
22468 {
22469 tree tmpl =
22473 else
22476 }
22481 {
22484 t);
22486 }
22489 {
22491 {
22493 {
22496 "ISO C++ 1998 forbids the use of %<extern%> on "
22498 }
22499 else
22501 "ISO C++ forbids the use of %qE"
22503 }
22511 else
22512 {
22514 storage);
22516 }
22517 }
22520 {
22521 /* DR 259 [temp.spec].
22523 Both an explicit instantiation and a declaration of an explicit
22524 specialization shall not appear in a program unless the explicit
22525 instantiation follows a declaration of the explicit specialization.
22527 For a given set of template parameters, if an explicit
22528 instantiation of a template appears after a declaration of an
22529 explicit specialization for that template, the explicit
22530 instantiation has no effect. */
22532 }
22534 {
22535 /* [temp.spec]
22537 No program shall explicitly instantiate any template more
22538 than once.
22540 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
22541 instantiation was `extern'. If EXTERN_P then the second is.
22542 These cases are OK. */
22549 /* If we've already instantiated the template, just return now. */
22552 }
22560 /* In contrast to implicit instantiation, where only the
22561 declarations, and not the definitions, of members are
22562 instantiated, we have here:
22564 [temp.explicit]
22566 The explicit instantiation of a class template specialization
22567 implies the instantiation of all of its members not
22568 previously explicitly specialized in the translation unit
22569 containing the explicit instantiation.
22571 Of course, we can't instantiate member template classes, since we
22572 don't have any arguments for them. Note that the standard is
22573 unclear on whether the instantiation of the members are
22574 *explicit* instantiations or not. However, the most natural
22575 interpretation is that it should be an explicit
22576 instantiation. */
22580 && !static_p
22583 {
22588 }
22593 }
22595 /* Given a function DECL, which is a specialization of TMPL, modify
22596 DECL to be a re-instantiation of TMPL with the same template
22597 arguments. TMPL should be the template into which tsubst'ing
22598 should occur for DECL, not the most general template.
22600 One reason for doing this is a scenario like this:
22602 template <class T>
22603 void f(const T&, int i);
22605 void g() { f(3, 7); }
22607 template <class T>
22608 void f(const T& t, const int i) { }
22610 Note that when the template is first instantiated, with
22611 instantiate_template, the resulting DECL will have no name for the
22612 first parameter, and the wrong type for the second. So, when we go
22613 to instantiate the DECL, we regenerate it. */
22615 static void
22617 {
22618 /* The arguments used to instantiate DECL, from the most general
22619 template. */
22620 tree code_pattern;
22624 /* Make sure that we can see identifiers, and compute access
22625 correctly. */
22629 {
22630 tree decl_parm;
22631 tree pattern_parm;
22632 tree specs;
22646 specs);
22648 /* Merge parameter declarations. */
22651 pattern_parm
22655 {
22656 tree parm_type;
22657 tree attributes;
22662 NULL_TREE);
22668 {
22671 }
22674 }
22675 /* Merge any parameters that match with the function parameter
22676 pack. */
22678 {
22680 tree expanded_types;
22681 /* Expand the TYPE_PACK_EXPANSION that provides the types for
22682 the parameters in this function parameter pack. */
22687 {
22688 tree parm_type;
22689 tree attributes;
22692 /* Rename the parameter to include the index. */
22701 {
22704 }
22706 }
22707 }
22708 /* Merge additional specifiers from the CODE_PATTERN. */
22712 }
22714 {
22724 }
22725 else
22729 }
22731 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
22732 substituted to get DECL. */
22734 tree
22736 {
22739 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
22740 for the instantiation. This is not always the most general
22741 template. Consider, for example:
22743 template <class T>
22744 struct S { template <class U> void f();
22745 template <> void f<int>(); };
22747 and an instantiation of S<double>::f<int>. We want TD to be the
22748 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
22750 more general template. */
22752 /* We must also deal with friend templates. Given:
22754 template <class T> struct S {
22755 template <class U> friend void f() {};
22756 };
22758 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
22759 so far as the language is concerned, but that's still
22760 where we get the pattern for the instantiation from. On
22761 other hand, if the definition comes outside the class, say:
22763 template <class T> struct S {
22764 template <class U> friend void f();
22765 };
22766 template <class U> friend void f() {}
22768 we don't need to look any further. That's what the check for
22769 DECL_INITIAL is for. */
22773 {
22774 /* The present template, TD, should not be a definition. If it
22775 were a definition, we should be using it! Note that we
22776 cannot restructure the loop to just keep going until we find
22777 a template with a definition, since that might go too far if
22778 a specialization was declared, but not defined. */
22780 /* Fetch the more general template. */
22782 }
22785 }
22787 /* Returns true if we need to instantiate this template instance even if we
22788 know we aren't going to emit it. */
22790 bool
22792 {
22793 /* We always instantiate inline functions so that we can inline them. An
22794 explicit instantiation declaration prohibits implicit instantiation of
22795 non-inline functions. With high levels of optimization, we would
22796 normally inline non-inline functions -- but we're not allowed to do
22797 that for "extern template" functions. Therefore, we check
22798 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
22802 /* And we need to instantiate static data members so that
22803 their initializers are available in integral constant
22804 expressions. */
22807 }
22809 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
22810 instantiate it now, modifying TREE_TYPE (fn). Returns false on
22811 error, true otherwise. */
22813 bool
22815 {
22818 /* Don't instantiate a noexcept-specification from template context. */
22833 {
22839 {
22840 /* If hash_set::add returns true, the element was already there. */
22845 fn);
22847 }
22849 {
22864 }
22865 else
22875 }
22878 {
22881 else
22883 }
22886 }
22888 /* We're starting to process the function INST, an instantiation of PATTERN;
22889 add their parameters to local_specializations. */
22891 static void
22893 {
22897 {
22901 }
22903 {
22905 {
22908 }
22909 else
22910 {
22911 /* Register the (value) argument pack as a specialization of
22912 TMPL_PARM, then move on. */
22915 }
22916 }
22918 }
22920 /* Produce the definition of D, a _DECL generated from a template. If
22921 DEFER_OK is true, then we don't have to actually do the
22922 instantiation now; we just have to do it sometime. Normally it is
22923 an error if this is an explicit instantiation but D is undefined.
22924 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
22925 instantiated class template. */
22927 tree
22929 {
22931 tree gen_args;
22932 tree args;
22933 tree td;
22934 tree code_pattern;
22935 tree spec;
22936 tree gen_tmpl;
22944 /* This function should only be used to instantiate templates for
22945 functions and static member variables. */
22948 /* A concept is never instantiated. */
22951 /* Variables are never deferred; if instantiation is required, they
22952 are instantiated right away. That allows for better code in the
22953 case that an expression refers to the value of the variable --
22954 if the variable has a constant value the referring expression can
22955 take advantage of that fact. */
22959 /* Don't instantiate cloned functions. Instead, instantiate the
22960 functions they cloned. */
22968 /* D has already been instantiated or explicitly specialized, so
22969 there's nothing for us to do here.
22971 It might seem reasonable to check whether or not D is an explicit
22972 instantiation, and, if so, stop here. But when an explicit
22973 instantiation is deferred until the end of the compilation,
22974 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
22975 the instantiation. */
22978 /* Check to see whether we know that this template will be
22979 instantiated in some other file, as with "extern template"
22980 extension. */
22983 /* In general, we do not instantiate such templates. */
22991 /* We should already have the extra args. */
22994 /* And what's in the hash table should match D. */
22998 /* This needs to happen before any tsubsting. */
23004 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
23005 for the instantiation. */
23010 {
23011 /* Look up an explicit specialization, if any. */
23015 {
23018 }
23019 }
23023 /* We should never be trying to instantiate a member of a class
23024 template or partial specialization. */
23029 /* In the case of a friend template whose definition is provided
23030 outside the class, we may have too many arguments. Drop the
23031 ones we don't need. The same is true for specializations. */
23032 args = get_innermost_template_args
23036 {
23042 }
23043 else
23044 {
23049 else
23051 }
23053 /* We may be in the middle of deferred access check. Disable it now. */
23056 /* Unless an explicit instantiation directive has already determined
23057 the linkage of D, remember that a definition is available for
23058 this entity. */
23068 /* If D is a member of an explicitly instantiated class template,
23069 and no definition is available, treat it like an implicit
23070 instantiation. */
23073 {
23074 /* Leave linkage flags alone on instantiations with anonymous
23075 visibility. */
23077 {
23080 }
23082 }
23084 /* Defer all other templates, unless we have been explicitly
23085 forbidden from doing so. */
23087 template. */
23088 ! pattern_defined
23089 /* If it's OK to postpone instantiation, do so. */
23090 || defer_ok
23091 /* If this is a static data member that will be defined
23092 elsewhere, we don't want to instantiate the entire data
23093 member, but we do want to instantiate the initializer so that
23094 we can substitute that elsewhere. */
23096 /* Handle here a deleted function too, avoid generating
23097 its body (c++/61080). */
23099 {
23100 /* The definition of the static data member is now required so
23101 we must substitute the initializer. */
23105 {
23106 tree ns;
23107 tree init;
23116 args,
23119 /* If instantiating the initializer involved instantiating this
23120 again, don't call cp_finish_decl twice. */
23122 {
23123 /* Make sure the initializer is still constant, in case of
23124 circular dependency (template/instantiate6.C). */
23125 const_init
23129 LOOKUP_ONLYCONVERTING);
23130 }
23134 }
23136 /* We restore the source position here because it's used by
23137 add_pending_template. */
23143 /* [temp.explicit]
23145 The definition of a non-exported function template, a
23146 non-exported member function template, or a non-exported
23147 member function or static data member of a class template
23148 shall be present in every translation unit in which it is
23149 explicitly instantiated. */
23153 /* If we're in unevaluated context, we just wanted to get the
23154 constant value; this isn't an odr use, so don't queue
23155 a full instantiation. */
23158 /* ??? Historically, we have instantiated inline functions, even
23159 when marked as "extern template". */
23163 }
23164 /* Tell the repository that D is available in this translation unit
23165 -- and see if it is supposed to be instantiated here. */
23167 {
23168 /* In a PCH file, despite the fact that the repository hasn't
23169 requested instantiation in the PCH it is still possible that
23170 an instantiation will be required in a file that includes the
23171 PCH. */
23174 /* Instantiate inline functions so that the inliner can do its
23175 job, even though we'll not be emitting a copy of this
23176 function. */
23179 }
23182 tree fn_context;
23193 else
23194 {
23198 }
23200 /* Mark D as instantiated so that recursive calls to
23201 instantiate_decl do not try to instantiate it again. */
23204 /* Regenerate the declaration in case the template has been modified
23205 by a subsequent redeclaration. */
23208 /* We already set the file and line above. Reset them now in case
23209 they changed as a result of calling regenerate_decl_from_template. */
23213 {
23214 tree init;
23217 /* Clear out DECL_RTL; whatever was there before may not be right
23218 since we've reset the type of the declaration. */
23222 /* The initializer is placed in DECL_INITIAL by
23223 regenerate_decl_from_template so we don't need to
23224 push/pop_access_scope again here. Pull it out so that
23225 cp_finish_decl can process it. */
23230 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
23231 initializer. That function will defer actual emission until
23232 we have a chance to determine linkage. */
23235 /* Enter the scope of D so that access-checking works correctly. */
23248 }
23252 {
23253 /* Set up the list of local specializations. */
23257 /* Set up context. */
23261 else
23264 /* Some typedefs referenced from within the template code need to be
23265 access checked at template instantiation time, i.e now. These
23266 types were added to the template at parsing time. Let's get those
23267 and perform the access checks then. */
23269 args);
23271 /* Create substitution entries for the parameters. */
23274 /* Substitute into the body of the function. */
23278 else
23279 {
23284 /* Set the current input_location to the end of the function
23285 so that finish_function knows where we are. */
23286 input_location
23289 /* Remember if we saw an infinite loop in the template. */
23290 current_function_infinite_loop
23292 }
23294 /* Finish the function. */
23298 else
23299 {
23302 }
23306 }
23308 /* We're not deferring instantiation any more. */
23313 else
23319 out:
23328 }
23330 /* Run through the list of templates that we wish we could
23331 instantiate, and instantiate any we can. RETRIES is the
23332 number of times we retry pending template instantiation. */
23334 void
23336 {
23340 /* Instantiating templates may trigger vtable generation. This in turn
23341 may require further template instantiations. We place a limit here
23342 to avoid infinite loop. */
23344 {
23348 "template instantiation depth exceeds maximum of %d"
23349 " instantiating %q+D, possibly from virtual table generation"
23353 /* Pretend that we defined it. */
23356 }
23358 do
23359 {
23364 {
23369 {
23371 {
23386 }
23389 }
23390 else
23391 {
23394 {
23395 instantiation
23401 }
23405 }
23408 /* If INSTANTIATION has been instantiated, then we don't
23409 need to consider it again in the future. */
23411 else
23412 {
23415 }
23418 }
23420 }
23424 }
23426 /* Substitute ARGVEC into T, which is a list of initializers for
23427 either base class or a non-static data member. The TREE_PURPOSEs
23428 are DECLs, and the TREE_VALUEs are the initializer values. Used by
23429 instantiate_decl. */
23431 static tree
23433 {
23437 {
23438 tree decl;
23439 tree init;
23445 {
23446 tree expr;
23447 tree arg;
23449 /* Expand the base class expansion type into separate base
23450 classes. */
23452 tf_warning_or_error,
23453 NULL_TREE);
23457 /* We'll be building separate TREE_LISTs of arguments for
23458 each base. */
23464 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
23465 expand each argument in the TREE_VALUE of t. */
23472 /* VOID_TYPE_NODE is used to indicate
23473 value-initialization. */
23474 {
23477 }
23478 else
23479 {
23480 /* Substitute parameter packs into each argument in the
23481 TREE_LIST. */
23484 {
23485 tree expanded_exprs;
23487 /* Expand the argument. */
23489 expanded_exprs
23491 tf_warning_or_error,
23492 NULL_TREE);
23496 /* Prepend each of the expanded expressions to the
23497 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
23499 {
23504 }
23505 }
23508 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
23509 since we built them backwards. */
23511 {
23514 }
23515 }
23516 }
23519 {
23521 {
23525 }
23526 else
23527 {
23528 tree tmp;
23543 /* If we had an initializer but it instantiated to nothing,
23544 value-initialize the object. This will only occur when
23545 the initializer was a pack expansion where the parameter
23546 packs used in that expansion were of length zero. */
23549 }
23552 {
23556 }
23557 }
23558 }
23560 }
23562 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
23564 static void
23566 {
23571 else
23573 }
23575 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
23576 is the instantiation (which should have been created with
23577 start_enum) and ARGS are the template arguments to use. */
23579 static void
23581 {
23582 tree e;
23588 {
23589 tree value;
23590 tree decl;
23593 /* Note that in a template enum, the TREE_VALUE is the
23594 CONST_DECL, not the corresponding INTEGER_CST. */
23599 /* Give this enumeration constant the correct access. */
23602 /* Actually build the enumerator itself. Here we're assuming that
23603 enumerators can't have dependent attributes. */
23606 }
23616 }
23618 /* DECL is a FUNCTION_DECL that is a template specialization. Return
23619 its type -- but without substituting the innermost set of template
23620 arguments. So, innermost set of template parameters will appear in
23621 the type. */
23623 tree
23625 {
23626 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
23628 }
23630 /* Return truthvalue if we're processing a template different from
23631 the last one involved in diagnostics. */
23632 bool
23634 {
23636 }
23638 /* Remember current template involved in diagnostics. */
23639 void
23641 {
23643 }
23647 {
23649 }
23651 /* Return TRUE if current_function_decl is being instantiated, false
23652 otherwise. */
23654 bool
23656 {
23659 }
23661 /* [temp.param] Check that template non-type parm TYPE is of an allowable
23662 type. Return false for ok, true for disallowed. Issue error and
23663 inform messages under control of COMPLAIN. */
23665 static bool
23667 {
23682 /* A bound template template parm could later be instantiated to have a valid
23683 nontype parm type via an alias template. */
23689 {
23692 else
23694 type);
23695 }
23697 }
23699 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
23700 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
23702 static bool
23704 {
23705 tree scope;
23707 /* [temp.dep.type]
23709 A type is dependent if it is:
23711 -- a template parameter. Template template parameters are types
23712 for us (since TYPE_P holds true for them) so we handle
23713 them here. */
23717 /* -- a qualified-id with a nested-name-specifier which contains a
23718 class-name that names a dependent type or whose unqualified-id
23719 names a dependent type. */
23723 /* An alias template specialization can be dependent even if the
23724 resulting type is not. */
23728 /* -- a cv-qualified type where the cv-unqualified type is
23729 dependent.
23730 No code is necessary for this bullet; the code below handles
23731 cv-qualified types, and we don't want to strip aliases with
23732 TYPE_MAIN_VARIANT because of DR 1558. */
23733 /* -- a compound type constructed from any dependent type. */
23743 {
23744 tree arg_type;
23749 arg_type;
23754 /* A value-dependent noexcept-specifier makes the type dependent. */
23757 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
23758 affect overload resolution and treating it as dependent breaks
23759 things. */
23764 }
23765 /* -- an array type constructed from any dependent type or whose
23766 size is specified by a constant expression that is
23767 value-dependent.
23769 We checked for type- and value-dependence of the bounds in
23770 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
23772 {
23777 }
23779 /* -- a template-id in which either the template name is a template
23780 parameter ... */
23783 /* ... or any of the template arguments is a dependent type or
23784 an expression that is type-dependent or value-dependent. */
23786 && (any_dependent_template_arguments_p
23790 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
23791 dependent; if the argument of the `typeof' expression is not
23792 type-dependent, then it should already been have resolved. */
23798 /* A template argument pack is dependent if any of its packed
23799 arguments are. */
23801 {
23807 }
23809 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
23810 be template parameters. */
23817 /* The standard does not specifically mention types that are local
23818 to template functions or local classes, but they should be
23819 considered dependent too. For example:
23821 template <int I> void f() {
23822 enum E { a = I };
23823 S<sizeof (E)> s;
23824 }
23826 The size of `E' cannot be known until the value of `I' has been
23827 determined. Therefore, `E' must be considered dependent. */
23831 /* Don't use type_dependent_expression_p here, as it can lead
23832 to infinite recursion trying to determine whether a lambda
23833 nested in a lambda is dependent (c++/47687). */
23837 && (any_dependent_template_arguments_p
23841 /* Other types are non-dependent. */
23843 }
23845 /* Returns TRUE if TYPE is dependent, in the sense of
23846 [temp.dep.type]. Note that a NULL type is considered dependent. */
23848 bool
23850 {
23851 /* If there are no template parameters in scope, then there can't be
23852 any dependent types. */
23854 {
23855 /* If we are not processing a template, then nobody should be
23856 providing us with a dependent type. */
23860 }
23862 /* If the type is NULL, we have not computed a type for the entity
23863 in question; in that case, the type is dependent. */
23867 /* Erroneous types can be considered non-dependent. */
23871 /* Getting here with global_type_node means we improperly called this
23872 function on the TREE_TYPE of an IDENTIFIER_NODE. */
23875 /* If we have not already computed the appropriate value for TYPE,
23876 do so now. */
23878 {
23881 }
23884 }
23886 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
23887 lookup. In other words, a dependent type that is not the current
23888 instantiation. */
23890 bool
23892 {
23895 }
23897 /* T is a SCOPE_REF; return whether we need to consider it
23898 instantiation-dependent so that we can check access at instantiation
23899 time even though we know which member it resolves to. */
23901 static bool
23903 {
23909 else
23911 }
23913 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
23914 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
23915 expression. */
23917 /* Note that this predicate is not appropriate for general expressions;
23918 only constant expressions (that satisfy potential_constant_expression)
23919 can be tested for value dependence. */
23921 bool
23923 {
23927 /* A type-dependent expression is also value-dependent. */
23932 {
23934 /* A dependent member function of the current instantiation. */
23938 /* A dependent member function of the current instantiation. */
23945 /* A name that has not been looked up -- must be dependent. */
23949 /* A non-type template parm. */
23953 /* A non-type template parm. */
23959 /* A constant with literal type and is initialized
23960 with an expression that is value-dependent.
23962 Note that a non-dependent parenthesized initializer will have
23963 already been replaced with its constant value, so if we see
23964 a TREE_LIST it must be dependent. */
23968 /* cp_finish_decl doesn't fold reference initializers. */
23973 {
23977 }
23986 /* These expressions are value-dependent if the type to which
23987 the cast occurs is dependent or the expression being casted
23988 is value-dependent. */
23989 {
23995 /* A functional cast has a list of operands. */
23998 {
23999 /* If there are no operands, it must be an expression such
24000 as "int()". This should not happen for aggregate types
24001 because it would form non-constant expressions. */
24006 }
24012 }
24017 /* FALLTHRU */
24020 /* A `sizeof' expression is value-dependent if the operand is
24021 type-dependent or is a pack expansion. */
24030 /* An 'encode' expression is value-dependent if the operand is
24031 type-dependent. */
24040 /* All instantiation-dependent expressions should also be considered
24041 value-dependent. */
24049 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
24050 is value-dependent. */
24051 {
24060 }
24063 {
24080 }
24091 {
24095 }
24098 /* Treat all requires-expressions as value-dependent so
24099 we don't try to fold them. */
24106 {
24113 {
24115 /* In a call to a constexpr member function, look through the
24116 implicit ADDR_EXPR on the object argument so that it doesn't
24117 cause the call to be considered value-dependent. We also
24118 look through it in potential_constant_expression. */
24125 }
24127 }
24133 {
24135 tree val;
24142 }
24145 /* Treat a GNU statement expression as dependent to avoid crashing
24146 under instantiate_non_dependent_expr; it can't be constant. */
24150 /* A constant expression is value-dependent if any subexpression is
24151 value-dependent. */
24153 {
24160 {
24164 {
24167 /* In some cases, some of the operands may be missing.
24168 (For example, in the case of PREDECREMENT_EXPR, the
24169 amount to increment by may be missing.) That doesn't
24170 make the expression dependent. */
24173 }
24174 }
24178 }
24180 }
24182 /* The expression is not value-dependent. */
24184 }
24186 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
24187 [temp.dep.expr]. Note that an expression with no type is
24188 considered dependent. Other parts of the compiler arrange for an
24189 expression with type-dependent subexpressions to have no type, so
24190 this function doesn't have to be fully recursive. */
24192 bool
24194 {
24201 /* An unresolved name is always dependent. */
24207 /* A fold expression is type-dependent. */
24214 /* Some expression forms are never type-dependent. */
24228 /* The types of these expressions depends only on the type to which
24229 the cast occurs. */
24238 /* The types of these expressions depends only on the type created
24239 by the expression. */
24242 {
24243 /* For NEW_EXPR tree nodes created inside a template, either
24244 the object type itself or a TREE_LIST may appear as the
24245 operand 1. */
24248 /* This is an array type. We need to check array dimensions
24249 as well. */
24251 || value_dependent_expression_p
24253 else
24255 }
24258 {
24262 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
24263 contains an identifier associated by name lookup with one or more
24264 declarations declared with a dependent type, or...a
24265 nested-name-specifier or qualified-id that names a member of an
24266 unknown specialization. */
24269 }
24279 {
24280 tree elt;
24284 {
24287 }
24289 }
24291 /* A static data member of the current instantiation with incomplete
24292 array type is type-dependent, as the definition and specializations
24293 can have different bounds. */
24300 /* An array of unknown bound depending on a variadic parameter, eg:
24302 template<typename... Args>
24303 void foo (Args... args)
24304 {
24305 int arr[] = { args... };
24306 }
24308 template<int... vals>
24309 void bar ()
24310 {
24311 int arr[] = { vals... };
24312 }
24314 If the array has no length and has an initializer, it must be that
24315 we couldn't determine its length in cp_complete_array_type because
24316 it is dependent. */
24324 /* A function or variable template-id is type-dependent if it has any
24325 dependent template arguments. */
24329 {
24330 /* Consider the innermost template arguments, since those are the ones
24331 that come from the template-id; the template arguments for the
24332 enclosing class do not make it type-dependent unless they are used in
24333 the type of the decl. */
24335 && (any_dependent_template_arguments_p
24338 }
24340 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
24341 type-dependent. Checking this is important for functions with auto return
24342 type, which looks like a dependent type. */
24350 {
24354 }
24356 /* Always dependent, on the number of arguments if nothing else. */
24361 {
24366 {
24372 }
24373 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
24378 {
24383 }
24386 {
24393 }
24403 }
24407 /* Dependent type attributes might not have made it from the decl to
24408 the type yet. */
24414 }
24416 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
24417 type-dependent if the expression refers to a member of the current
24418 instantiation and the type of the referenced member is dependent, or the
24419 class member access expression refers to a member of an unknown
24420 specialization.
24422 This function returns true if the OBJECT in such a class member access
24423 expression is of an unknown specialization. */
24425 bool
24427 {
24428 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
24429 dependent. */
24434 }
24436 /* walk_tree callback function for instantiation_dependent_expression_p,
24437 below. Returns non-zero if a dependent subexpression is found. */
24439 static tree
24442 {
24444 {
24445 /* We don't have to worry about decltype currently because decltype
24446 of an instantiation-dependent expr is a dependent type. This
24447 might change depending on the resolution of DR 1172. */
24450 }
24453 {
24454 /* Don't treat an argument list as dependent just because it has no
24455 TREE_TYPE. */
24463 /* Handle expressions with type operands. */
24468 {
24473 {
24476 else
24477 {
24480 }
24481 }
24483 }
24487 /* In a template, finish_class_member_access_expr creates a
24488 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
24489 type-dependent, so that we can check access control at
24490 instantiation time (PR 42277). See also Core issue 1273. */
24497 else
24500 /* Treat statement-expressions as dependent. */
24504 /* Treat requires-expressions as dependent. */
24509 /* Treat calls to function concepts as dependent. */
24515 /* And variable concepts. */
24522 }
24526 else
24528 }
24530 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
24531 sense defined by the ABI:
24533 "An expression is instantiation-dependent if it is type-dependent
24534 or value-dependent, or it has a subexpression that is type-dependent
24535 or value-dependent."
24537 Except don't actually check value-dependence for unevaluated expressions,
24538 because in sizeof(i) we don't care about the value of i. Checking
24539 type-dependence will in turn check value-dependence of array bounds/template
24540 arguments as needed. */
24542 bool
24544 {
24545 tree result;
24556 }
24558 /* As above, but also check value-dependence of the expression as a whole. */
24560 bool
24562 {
24565 }
24567 /* Like type_dependent_expression_p, but it also works while not processing
24568 a template definition, i.e. during substitution or mangling. */
24570 bool
24572 {
24578 }
24580 /* Returns TRUE if ARGS contains a type-dependent expression. */
24582 bool
24584 {
24586 tree arg;
24589 {
24592 }
24594 }
24596 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24597 expressions) contains any type-dependent expressions. */
24599 bool
24601 {
24607 }
24609 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24610 expressions) contains any value-dependent expressions. */
24612 bool
24614 {
24620 }
24622 /* Returns TRUE if the ARG (a template argument) is dependent. */
24624 bool
24626 {
24630 /* Assume a template argument that was wrongly written by the user
24631 is dependent. This is consistent with what
24632 any_dependent_template_arguments_p [that calls this function]
24633 does. */
24643 {
24646 /* A member template of a dependent class is not necessarily
24647 type-dependent, but it is a dependent template argument because it
24648 will be a member of an unknown specialization to that template. */
24651 }
24653 {
24657 {
24660 }
24663 }
24666 else
24669 }
24671 /* Returns true if ARGS (a collection of template arguments) contains
24672 any types that require structural equality testing. */
24674 bool
24676 {
24686 {
24689 {
24695 {
24696 /* Look inside the argument pack. */
24699 }
24702 {
24715 }
24716 }
24717 }
24720 }
24722 /* Returns true if ARGS (a collection of template arguments) contains
24723 any dependent arguments. */
24725 bool
24727 {
24737 {
24742 }
24745 }
24747 /* Returns TRUE if the template TMPL is type-dependent. */
24749 bool
24751 {
24753 {
24758 }
24760 /* Template template parameters are dependent. */
24764 /* So are names that have not been looked up. */
24768 }
24770 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
24772 bool
24774 {
24777 }
24779 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
24780 are dependent. */
24782 bool
24784 {
24791 {
24813 {
24817 }
24821 {
24825 {
24830 }
24831 }
24832 }
24835 }
24837 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
24838 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
24839 no such TYPE can be found. Note that this function peers inside
24840 uninstantiated templates and therefore should be used only in
24841 extremely limited situations. ONLY_CURRENT_P restricts this
24842 peering to the currently open classes hierarchy (which is required
24843 when comparing types). */
24845 tree
24847 {
24848 tree scope;
24849 tree name;
24850 tree decl;
24852 tree pushed_scope;
24853 tree result;
24858 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
24859 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
24860 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
24861 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
24862 identifier of the TYPENAME_TYPE anymore.
24863 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
24864 TYPENAME_TYPE instead, we avoid messing up with a possible
24865 typedef variant case. */
24868 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
24869 it first before we can figure out what NAME refers to. */
24871 {
24873 /* Given a class template A with a dependent base with nested type C,
24874 typedef typename A::C::C C will land us here, as trying to resolve
24875 the initial A::C leads to the local C typedef, which leads back to
24876 A::C::C. So we break the recursion now. */
24878 else
24880 }
24881 /* If we don't know what SCOPE refers to, then we cannot resolve the
24882 TYPENAME_TYPE. */
24885 /* If this is a typedef, we don't want to look inside (c++/11987). */
24888 /* If SCOPE isn't the template itself, it will not have a valid
24889 TYPE_FIELDS list. */
24891 /* scope is either the template itself or a compatible instantiation
24892 like X<T>, so look up the name in the original template. */
24894 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
24896 /* If scope has no fields, it can't be a current instantiation. Check this
24897 before currently_open_class to avoid infinite recursion (71515). */
24900 /* If the SCOPE is not the current instantiation, there's no reason
24901 to look inside it. */
24904 /* Enter the SCOPE so that name lookup will be resolved as if we
24905 were in the class definition. In particular, SCOPE will no
24906 longer be considered a dependent type. */
24908 /* Look up the declaration. */
24910 tf_warning_or_error);
24914 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
24915 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
24921 {
24925 }
24928 {
24929 /* Obtain the template and the arguments. */
24932 {
24933 /* We get here with a plain identifier because a previous tentative
24934 parse of the nested-name-specifier as part of a ptr-operator saw
24935 ::template X<A>. The use of ::template is necessary in a
24936 ptr-operator, but wrong in a declarator-id.
24938 [temp.names]: In a qualified-id of a declarator-id, the keyword
24939 template shall not appear at the top level. */
24943 }
24945 /* Instantiate the template. */
24951 }
24953 /* Leave the SCOPE. */
24957 /* If we failed to resolve it, return the original typename. */
24961 /* If lookup found a typename type, resolve that too. */
24963 {
24964 /* Ill-formed programs can cause infinite recursion here, so we
24965 must catch that. */
24969 }
24971 /* Qualify the resulting type. */
24977 }
24979 /* EXPR is an expression which is not type-dependent. Return a proxy
24980 for EXPR that can be used to compute the types of larger
24981 expressions containing EXPR. */
24983 tree
24985 {
24986 tree inner_expr;
24988 /* When checking, try to get a constant value for all non-dependent
24989 expressions in order to expose bugs in *_dependent_expression_p
24990 and constexpr. This can affect code generation, see PR70704, so
24991 only do this for -fchecking=2. */
24994 /* Don't do this during nsdmi parsing as it can lead to
24995 unexpected recursive instantiations. */
24997 /* Don't do this during concept expansion either and for
24998 the same reason. */
25002 /* Preserve OVERLOADs; the functions must be available to resolve
25003 types. */
25014 /* There is no need to return a proxy for a variable. */
25017 /* Preserve string constants; conversions from string constants to
25018 "char *" are allowed, even though normally a "const char *"
25019 cannot be used to initialize a "char *". */
25022 /* Preserve void and arithmetic constants, as an optimization -- there is no
25023 reason to create a new node. */
25028 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
25029 There is at least one place where we want to know that a
25030 particular expression is a throw-expression: when checking a ?:
25031 expression, there are special rules if the second or third
25032 argument is a throw-expression. */
25036 /* Don't wrap an initializer list, we need to be able to look inside. */
25040 /* Don't wrap a dummy object, we need to be able to test for it. */
25059 /* If the type is unknown, it can't really be non-dependent */
25062 /* Otherwise, build a NON_DEPENDENT_EXPR. */
25064 }
25066 /* ARGS is a vector of expressions as arguments to a function call.
25067 Replace the arguments with equivalent non-dependent expressions.
25068 This modifies ARGS in place. */
25070 void
25072 {
25074 tree arg;
25077 {
25081 }
25082 }
25084 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
25085 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
25086 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
25088 static tree
25090 {
25104 }
25106 tree
25108 {
25110 }
25112 tree
25114 {
25116 }
25118 /* Return a C++17 deduction placeholder for class template TMPL. */
25120 tree
25122 {
25126 }
25128 /* True iff T is a C++17 class template deduction placeholder. */
25130 bool
25132 {
25134 }
25136 /* Make a "constrained auto" type-specifier. This is an
25137 auto type with constraints that must be associated after
25138 deduction. The constraint is formed from the given
25139 CONC and its optional sequence of arguments, which are
25140 non-null if written as partial-concept-id. */
25142 tree
25144 {
25147 /* Build the constraint. */
25155 /* Our canonical type depends on the constraint. */
25158 /* Attach the constraint to the type declaration. */
25161 }
25163 /* Given type ARG, return std::initializer_list<ARG>. */
25165 static tree
25167 {
25171 {
25175 "deducing from brace-enclosed initializer list"
25179 }
25185 }
25187 /* Replace auto in TYPE with std::initializer_list<auto>. */
25189 static tree
25191 {
25198 }
25200 /* Hash traits for hashing possibly constrained 'auto'
25201 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
25204 {
25207 };
25209 /* Hash the 'auto' T. */
25211 inline hashval_t
25213 {
25215 /* Matching constrained-type-specifiers denote the same template
25216 parameter, so hash the constraint. */
25218 else
25219 /* But unconstrained autos are all separate, so just hash the pointer. */
25221 }
25223 /* Compare two 'auto's. */
25227 {
25234 /* Two unconstrained autos are distinct. */
25239 }
25241 /* for_each_template_parm callback for extract_autos: if t is a (possibly
25242 constrained) auto, add it to the vector. */
25244 static int
25246 {
25249 {
25250 /* All the autos were built with index 0; fix that up now. */
25254 /* If this is a repeated constrained-type-specifier, use the index we
25255 chose before. */
25257 else
25258 {
25259 /* Otherwise this is new, so use the current count. */
25262 }
25264 }
25266 /* Always keep walking. */
25268 }
25270 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
25271 says they can appear anywhere in the type. */
25273 static tree
25275 {
25284 {
25289 }
25292 }
25294 /* The stem for deduction guide names. */
25297 /* Return the name for a deduction guide for class template TMPL. */
25299 tree
25301 {
25312 }
25314 /* True if NAME is the name of a deduction guide. */
25316 bool
25318 {
25322 }
25324 /* True if FN is a deduction guide. */
25326 bool
25328 {
25333 }
25335 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
25337 bool
25339 {
25346 }
25348 /* True if FN is a guide generated from a constructor template. */
25350 bool
25352 {
25360 }
25362 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
25363 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
25364 template parameter types. Note that the handling of template template
25365 parameters relies on current_template_parms being set appropriately for the
25366 new template. */
25368 static tree
25371 {
25374 tree newtype;
25377 {
25384 }
25385 else
25389 tree newdecl
25394 tree newidx;
25397 {
25407 {
25412 // First create a copy (ttargs) of tsubst_args with an
25413 // additional level for the template template parameter's own
25414 // template parameters (ttparms).
25415 tree ttparms = (INNERMOST_TEMPLATE_PARMS
25423 // Substitute ttargs into ttparms to fix references to
25424 // other template parameters.
25426 complain);
25427 // Now substitute again with args based on tparms, to reduce
25428 // the level of the ttparms.
25431 complain);
25432 // Finally, tack the adjusted parms onto tparms.
25434 current_template_parms);
25436 }
25437 }
25438 else
25439 {
25441 tree newconst
25453 }
25456 }
25458 /* Returns a C++17 class deduction guide template based on the constructor
25459 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
25460 guide, or REFERENCE_TYPE for an implicit copy/move guide. */
25462 static tree
25464 {
25468 location_t loc;
25472 {
25476 {
25479 }
25480 else
25490 }
25491 else
25492 {
25495 fn_tmpl
25505 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
25506 fully specialized args for the enclosing class. Strip those off, as
25507 the deduction guide won't have those template parameters. */
25510 /* Discard the 'this' parameter. */
25518 {
25521 /* For a member template constructor, we need to flatten the two
25522 template parameter lists into one, and then adjust the function
25523 signature accordingly. This gets...complicated. */
25526 /* For a member template we should have two levels of parms/args, one
25527 for the class and one for the constructor. We stripped
25528 specialized args for further enclosing classes above. */
25532 /* Template args for translating references to the two-level template
25533 parameters into references to the one-level template parameters we
25534 are creating. */
25539 /* Template parms for the constructor template. */
25542 /* Template parms for the class template. */
25546 /* Template parms for the deduction guide start as a copy of the
25547 template parms for the class. We set current_template_parms for
25548 lookup_template_class_1. */
25554 /* Now we need to rewrite the constructor parms to append them to the
25555 class parms. */
25557 {
25572 }
25574 /* Now we have a final set of template parms to substitute into the
25575 function signature. */
25584 }
25586 }
25589 {
25590 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
25594 }
25598 FUNCTION_DECL,
25615 }
25617 /* Deduce template arguments for the class template placeholder PTYPE for
25618 template TMPL based on the initializer INIT, and return the resulting
25619 type. */
25621 static tree
25623 tsubst_flags_t complain)
25624 {
25626 {
25627 /* We should have handled this in the caller. */
25633 }
25644 {
25647 {
25648 /* As an exception, the first phase in 16.3.1.7 (considering the
25649 initializer list as a single argument) is omitted if the
25650 initializer list consists of a single expression of type cv U,
25651 where U is a specialization of C or a class derived from a
25652 specialization of C. */
25663 }
25666 else
25668 }
25669 else
25680 /* Prune explicit deduction guides in copy-initialization context. */
25682 {
25688 {
25689 /* Found a nonconverting guide, prune the candidates. */
25696 }
25697 }
25702 {
25705 }
25708 // FIXME cache artificial deduction guides
25710 {
25715 else
25719 }
25723 /* If this is list-initialization and the class has a list constructor, first
25724 try deducing from the list as a single argument, as [over.match.list]. */
25728 {
25732 }
25734 {
25740 {
25741 /* That didn't work, now try treating the list as a sequence of
25742 arguments. */
25745 }
25746 }
25748 /* Maybe generate an implicit deduction guide. */
25750 {
25754 /* Generate a copy guide. */
25757 /* Generate a default guide. */
25761 {
25764 }
25765 }
25768 {
25770 " of %qT, as it has no non-explicit deduction guides or "
25773 }
25775 {
25779 }
25782 {
25786 }
25789 {
25799 }
25804 }
25806 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25807 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
25809 tree
25811 {
25813 tf_warning_or_error,
25814 adc_unspecified);
25815 }
25817 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25818 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
25819 The CONTEXT determines the context in which auto deduction is performed
25820 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
25821 OUTER_TARGS are used during template argument deduction
25822 (context == adc_unify) to properly substitute the result, and is ignored
25823 in other contexts.
25825 For partial-concept-ids, extra args may be appended to the list of deduced
25826 template arguments prior to determining constraint satisfaction. */
25828 tree
25832 {
25833 tree targs;
25840 /* Defining a subset of type-dependent expressions that we can deduce
25841 from ahead of time isn't worth the trouble. */
25845 /* C++17 class template argument deduction. */
25849 /* Nothing we can do with this, even in deduction context. */
25852 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
25853 with either a new invented type template parameter U or, if the
25854 initializer is a braced-init-list (8.5.4), with
25855 std::initializer_list<U>. */
25857 {
25862 else
25863 {
25865 {
25869 "for deduction to %<std::initializer_list%>, use copy-"
25871 }
25873 }
25874 }
25885 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
25886 and initializer has array type, deduce cv-qualified array type. */
25888 complain);
25890 {
25899 {
25903 }
25904 }
25905 else
25906 {
25908 tree tparms;
25912 else
25913 {
25917 }
25924 {
25926 /* Try again at instantiation time. */
25930 /* If type is error_mark_node a diagnostic must have been
25931 emitted by now. Also, having a mention to '<type error>'
25932 in the diagnostic is not really useful to the user. */
25933 {
25937 else
25942 }
25944 }
25945 }
25947 /* Check any placeholder constraints against the deduced type. */
25950 {
25951 /* Use the deduced type to check the associated constraints. If we
25952 have a partial-concept-id, rebuild the argument list so that
25953 we check using the extra arguments. */
25957 {
25960 }
25961 else
25964 {
25966 {
25968 {
25986 }
25988 }
25990 }
25991 }
25997 }
25999 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
26000 result. */
26002 tree
26004 {
26006 {
26012 /* In an abbreviated function template we didn't know we were dealing
26013 with a function template when we saw the auto return type, so update
26014 it to have the correct level. */
26016 }
26018 }
26020 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
26021 'decltype(auto)' or a deduced class template. */
26023 bool
26025 {
26031 else
26033 }
26035 /* for_each_template_parm callback for type_uses_auto. */
26037 int
26039 {
26041 }
26043 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
26044 a use of `auto'. Returns NULL_TREE otherwise. */
26046 tree
26048 {
26052 {
26053 /* The Concepts TS allows multiple autos in one type-specifier; just
26054 return the first one we find, do_auto_deduction will collect all of
26055 them. */
26059 else
26061 }
26062 else
26064 }
26066 /* For a given template T, return the vector of typedefs referenced
26067 in T for which access check is needed at T instantiation time.
26068 T is either a FUNCTION_DECL or a RECORD_TYPE.
26069 Those typedefs were added to T by the function
26070 append_type_to_template_for_access_check. */
26074 {
26075 tree ti;
26086 {
26091 }
26094 }
26096 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
26097 tied to T. That list of typedefs will be access checked at
26098 T instantiation time.
26099 T is either a FUNCTION_DECL or a RECORD_TYPE.
26100 TYPE_DECL is a TYPE_DECL node representing a typedef.
26101 SCOPE is the scope through which TYPE_DECL is accessed.
26102 LOCATION is the location of the usage point of TYPE_DECL.
26104 This function is a subroutine of
26105 append_type_to_template_for_access_check. */
26107 static void
26109 tree type_decl,
26110 tree scope,
26111 location_t location)
26112 {
26113 qualified_typedef_usage_t typedef_usage;
26114 tree ti;
26121 && type_decl
26135 }
26137 /* Append TYPE_DECL to the template TEMPL.
26138 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
26139 At TEMPL instanciation time, TYPE_DECL will be checked to see
26140 if it can be accessed through SCOPE.
26141 LOCATION is the location of the usage point of TYPE_DECL.
26143 e.g. consider the following code snippet:
26145 class C
26146 {
26147 typedef int myint;
26148 };
26150 template<class U> struct S
26151 {
26152 C::myint mi; // <-- usage point of the typedef C::myint
26153 };
26155 S<char> s;
26157 At S<char> instantiation time, we need to check the access of C::myint
26158 In other words, we need to check the access of the myint typedef through
26159 the C scope. For that purpose, this function will add the myint typedef
26160 and the scope C through which its being accessed to a list of typedefs
26161 tied to the template S. That list will be walked at template instantiation
26162 time and access check performed on each typedefs it contains.
26163 Note that this particular code snippet should yield an error because
26164 myint is private to C. */
26166 void
26168 tree type_decl,
26169 tree scope,
26170 location_t location)
26171 {
26177 /* Make sure we don't append the type to the template twice. */
26184 }
26186 /* Convert the generic type parameters in PARM that match the types given in the
26187 range [START_IDX, END_IDX) from the current_template_parms into generic type
26188 packs. */
26190 tree
26192 {
26203 {
26204 /* Create a distinct parameter pack type from the current parm and add it
26205 to the replacement args to tsubst below into the generic function
26206 parameter. */
26221 }
26227 /* If there are more levels then build up the replacement with the outer
26228 template parms. */
26232 replacement);
26235 }
26237 /* Entries in the decl_constraint hash table. */
26239 {
26240 tree decl;
26241 tree ci;
26242 };
26244 /* Hashing function and equality for constraint entries. */
26246 {
26248 {
26250 }
26253 {
26255 }
26256 };
26258 /* A mapping from declarations to constraint information. Note that
26259 both templates and their underlying declarations are mapped to the
26260 same constraint information.
26262 FIXME: This is defined in pt.c because garbage collection
26263 code is not being generated for constraint.cc. */
26267 /* Returns the template constraints of declaration T. If T is not
26268 constrained, return NULL_TREE. Note that T must be non-null. */
26270 tree
26272 {
26283 else
26285 }
26287 /* Associate the given constraint information CI with the declaration
26288 T. If T is a template, then the constraints are associated with
26289 its underlying declaration. Don't build associations if CI is
26290 NULL_TREE. */
26292 void
26294 {
26306 }
26308 /* Remove the associated constraints of the declaration T. */
26310 void
26312 {
26321 }
26323 /* Memoized satisfaction results for declarations. This
26324 maps the pair (constraint_info, arguments) to the result computed
26325 by constraints_satisfied_p. */
26328 {
26329 tree ci;
26330 tree args;
26331 tree result;
26332 };
26334 /* Hashing function and equality for constraint entries. */
26337 {
26339 {
26342 }
26345 {
26347 }
26348 };
26350 /* Memoized satisfaction results for concept checks. */
26353 {
26354 tree tmpl;
26355 tree args;
26356 tree result;
26357 };
26359 /* Hashing function and equality for constraint entries. */
26362 {
26364 {
26366 }
26369 {
26374 }
26375 };
26380 /* Search for a memoized satisfaction result. Returns one of the
26381 truth value nodes if previously memoized, or NULL_TREE otherwise. */
26383 tree
26385 {
26390 else
26392 }
26394 /* Memoize the result of a satisfication test. Returns the saved result. */
26396 tree
26398 {
26405 }
26407 /* Search for a memoized satisfaction result for a concept. */
26409 tree
26411 {
26416 else
26418 }
26420 /* Memoize the result of a concept check. Returns the saved result. */
26422 tree
26424 {
26431 }
26435 /* Returns a prior concept specialization. This returns the substituted
26436 and normalized constraints defined by the concept. */
26438 tree
26440 {
26445 else
26447 }
26449 /* Save a concept expansion for later. */
26451 tree
26453 {
26460 }
26462 static hashval_t
26464 {
26473 }
26475 /* Compare the constraints of two subsumption entries. The LEFT1 and
26476 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
26477 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
26479 static bool
26481 {
26489 }
26491 /* Key/value pair for learning and memoizing subsumption results. This
26492 associates a pair of check constraints (including arguments) with
26493 a boolean value indicating the result. */
26496 {
26497 tree t1;
26498 tree t2;
26500 };
26502 /* Hashing function and equality for constraint entries. */
26505 {
26507 {
26509 }
26512 {
26517 }
26518 };
26522 /* Search for a previously cached subsumption result. */
26526 {
26531 else
26533 }
26535 /* Save a subsumption result. */
26537 bool
26539 {
26546 }
26548 /* Set up the hash table for constraint association. */
26550 void
26552 {
26561 }
26563 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
26564 0..N-1. */
26566 void
26568 {
26571 integer_type_node,
26572 NULL_TREE),
26576 }
26578 /* Set up the hash tables for template instantiations. */
26580 void
26582 {
26588 }
26590 /* Print stats about the template hash tables for -fstats. */
26592 void
26594 {
26603 }