| blob | d93d518c22d88de1a2277af3767c5a7733375a88 |
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 {
1899 }
1901 /* TYPE is a class type. Returns true if TYPE is an explicitly
1902 specialized class. */
1904 bool
1906 {
1910 }
1912 /* Print the list of functions at FNS, going through all the overloads
1913 for each element of the list. Alternatively, FNS can not be a
1914 TREE_LIST, in which case it will be printed together with all the
1915 overloads.
1917 MORE and *STR should respectively be FALSE and NULL when the function
1918 is called from the outside. They are used internally on recursive
1919 calls. print_candidates manages the two parameters and leaves NULL
1920 in *STR when it ends. */
1922 static void
1924 {
1928 else
1930 {
1936 {
1939 else
1942 }
1944 }
1945 }
1947 /* Print the list of candidate FNS in an error message. FNS can also
1948 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1950 void
1952 {
1956 }
1958 /* Get a (possibly) constrained template declaration for the
1959 purpose of ordering candidates. */
1960 static tree
1962 {
1968 }
1970 /* Among candidates having the same signature, return the
1971 most constrained or NULL_TREE if there is no best candidate.
1972 If the signatures of candidates vary (e.g., template
1973 specialization vs. member function), then there can be no
1974 most constrained.
1976 Note that we don't compare constraints on the functions
1977 themselves, but rather those of their templates. */
1978 static tree
1980 {
1981 // Try to find the best candidate in a first pass.
1984 {
1991 }
1993 // Verify that the champ is better than previous candidates.
1998 }
2001 }
2004 /* Returns the template (one of the functions given by TEMPLATE_ID)
2005 which can be specialized to match the indicated DECL with the
2006 explicit template args given in TEMPLATE_ID. The DECL may be
2007 NULL_TREE if none is available. In that case, the functions in
2008 TEMPLATE_ID are non-members.
2010 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2011 specialization of a member template.
2013 The TEMPLATE_COUNT is the number of references to qualifying
2014 template classes that appeared in the name of the function. See
2015 check_explicit_specialization for a more accurate description.
2017 TSK indicates what kind of template declaration (if any) is being
2018 declared. TSK_TEMPLATE indicates that the declaration given by
2019 DECL, though a FUNCTION_DECL, has template parameters, and is
2020 therefore a template function.
2022 The template args (those explicitly specified and those deduced)
2023 are output in a newly created vector *TARGS_OUT.
2025 If it is impossible to determine the result, an error message is
2026 issued. The error_mark_node is returned to indicate failure. */
2028 static tree
2030 tree decl,
2034 tmpl_spec_kind tsk)
2035 {
2036 tree fns;
2037 tree targs;
2038 tree explicit_targs;
2041 /* A TREE_LIST of templates of which DECL may be a specialization.
2042 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2043 corresponding TREE_PURPOSE is the set of template arguments that,
2044 when used to instantiate the template, would produce a function
2045 with the signature of DECL. */
2055 /* We shouldn't be specializing a member template of an
2056 unspecialized class template; we already gave an error in
2057 check_specialization_scope, now avoid crashing. */
2060 {
2063 }
2071 /* Check for baselinks. */
2076 {
2079 }
2081 {
2084 }
2086 /* Count the number of template headers specified for this
2087 specialization. */
2097 {
2100 tf_warning_or_error,
2104 }
2106 {
2110 {
2111 tree decl_arg_types;
2112 tree fn_arg_types;
2113 tree insttype;
2115 /* In case of explicit specialization, we need to check if
2116 the number of template headers appearing in the specialization
2117 is correct. This is usually done in check_explicit_specialization,
2118 but the check done there cannot be exhaustive when specializing
2119 member functions. Consider the following code:
2121 template <> void A<int>::f(int);
2122 template <> template <> void A<int>::f(int);
2124 Assuming that A<int> is not itself an explicit specialization
2125 already, the first line specializes "f" which is a non-template
2126 member function, whilst the second line specializes "f" which
2127 is a template member function. So both lines are syntactically
2128 correct, and check_explicit_specialization does not reject
2129 them.
2131 Here, we can do better, as we are matching the specialization
2132 against the declarations. We count the number of template
2133 headers, and we check if they match TEMPLATE_COUNT + 1
2134 (TEMPLATE_COUNT is the number of qualifying template classes,
2135 plus there must be another header for the member template
2136 itself).
2138 Notice that if header_count is zero, this is not a
2139 specialization but rather a template instantiation, so there
2140 is no check we can perform here. */
2144 /* Check that the number of template arguments at the
2145 innermost level for DECL is the same as for FN. */
2153 /* DECL might be a specialization of FN. */
2157 /* For a non-static member function, we need to make sure
2158 that the const qualification is the same. Since
2159 get_bindings does not try to merge the "this" parameter,
2160 we must do the comparison explicitly. */
2166 /* Skip the "this" parameter and, for constructors of
2167 classes with virtual bases, the VTT parameter. A
2168 full specialization of a constructor will have a VTT
2169 parameter, but a template never will. */
2170 decl_arg_types
2172 fn_arg_types
2175 /* Function templates cannot be specializations; there are
2176 no partial specializations of functions. Therefore, if
2177 the type of DECL does not match FN, there is no
2178 match.
2180 Note that it should never be the case that we have both
2181 candidates added here, and for regular member functions
2182 below. */
2184 {
2188 }
2190 /* See whether this function might be a specialization of this
2191 template. Suppress access control because we might be trying
2192 to make this specialization a friend, and we have already done
2193 access control for the declaration of the specialization. */
2199 /* We cannot deduce template arguments that when used to
2200 specialize TMPL will produce DECL. */
2203 /* Remove, from the set of candidates, all those functions
2204 whose constraints are not satisfied. */
2208 // Then, try to form the new function type.
2212 fn_arg_types
2217 /* Save this template, and the arguments deduced. */
2219 }
2221 /* FN is an ordinary member function, and we need a
2222 specialization of a member template. */
2223 ;
2225 /* We can get IDENTIFIER_NODEs here in certain erroneous
2226 cases. */
2227 ;
2229 /* This is just an ordinary non-member function. Nothing can
2230 be a specialization of that. */
2231 ;
2233 /* Cannot specialize functions that are created implicitly. */
2234 ;
2235 else
2236 {
2237 tree decl_arg_types;
2239 /* This is an ordinary member function. However, since
2240 we're here, we can assume its enclosing class is a
2241 template class. For example,
2243 template <typename T> struct S { void f(); };
2244 template <> void S<int>::f() {}
2246 Here, S<int>::f is a non-template, but S<int> is a
2247 template class. If FN has the same type as DECL, we
2248 might be in business. */
2251 /* Its enclosing class is an explicit specialization
2252 of a template class. This is not a candidate. */
2257 /* The return types differ. */
2260 /* Adjust the type of DECL in case FN is a static member. */
2267 decl_arg_types))
2270 // If the deduced arguments do not satisfy the constraints,
2271 // this is not a candidate.
2275 // Add the candidate.
2277 }
2278 }
2281 {
2282 /* We have:
2284 [temp.expl.spec]
2286 It is possible for a specialization with a given function
2287 signature to be instantiated from more than one function
2288 template. In such cases, explicit specification of the
2289 template arguments must be used to uniquely identify the
2290 function template specialization being specialized.
2292 Note that here, there's no suggestion that we're supposed to
2293 determine which of the candidate templates is most
2294 specialized. However, we, also have:
2296 [temp.func.order]
2298 Partial ordering of overloaded function template
2299 declarations is used in the following contexts to select
2300 the function template to which a function template
2301 specialization refers:
2303 -- when an explicit specialization refers to a function
2304 template.
2306 So, we do use the partial ordering rules, at least for now.
2307 This extension can only serve to make invalid programs valid,
2308 so it's safe. And, there is strong anecdotal evidence that
2309 the committee intended the partial ordering rules to apply;
2310 the EDG front end has that behavior, and John Spicer claims
2311 that the committee simply forgot to delete the wording in
2312 [temp.expl.spec]. */
2315 {
2318 }
2319 }
2321 // Concepts allows multiple declarations of member functions
2322 // with the same signature. Like above, we need to rely on
2323 // on the partial ordering of those candidates to determine which
2324 // is the best.
2326 {
2328 {
2331 }
2332 }
2335 {
2342 else
2345 }
2349 {
2355 }
2357 /* We have one, and exactly one, match. */
2359 {
2363 // Propagate the candidate's constraints to the declaration.
2366 /* DECL is a re-declaration or partial instantiation of a template
2367 function. */
2370 /* It was a specialization of an ordinary member function in a
2371 template class. */
2373 }
2375 /* It was a specialization of a template. */
2378 {
2383 }
2384 else
2387 }
2389 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2390 but with the default argument values filled in from those in the
2391 TMPL_TYPES. */
2393 static tree
2395 tree tmpl_types)
2396 {
2397 tree new_spec_types;
2405 /* Substitute into the rest of the list. */
2406 new_spec_types =
2410 /* Add the default argument for this parameter. */
2413 new_spec_types);
2414 }
2416 /* DECL is an explicit specialization. Replicate default arguments
2417 from the template it specializes. (That way, code like:
2419 template <class T> void f(T = 3);
2420 template <> void f(double);
2421 void g () { f (); }
2423 works, as required.) An alternative approach would be to look up
2424 the correct default arguments at the call-site, but this approach
2425 is consistent with how implicit instantiations are handled. */
2427 static void
2429 {
2430 tree tmpl;
2431 tree spec_types;
2432 tree tmpl_types;
2433 tree new_spec_types;
2434 tree old_type;
2435 tree new_type;
2436 tree t;
2441 /* See if there's anything we need to do. */
2454 {
2455 /* Remove the this pointer, but remember the object's type for
2456 CV quals. */
2462 {
2463 /* DECL may contain more parameters than TMPL due to the extra
2464 in-charge parameter in constructors and destructors. */
2467 }
2469 {
2472 }
2473 }
2475 /* Compute the merged default arguments. */
2476 new_spec_types =
2479 /* Compute the new FUNCTION_TYPE. */
2481 {
2485 new_spec_types);
2488 /* Put the in-charge parameter back. */
2491 new_spec_types);
2495 new_spec_types);
2496 }
2497 else
2499 new_spec_types);
2509 }
2511 /* Return the number of template headers we expect to see for a definition
2512 or specialization of CTYPE or one of its non-template members. */
2514 int
2516 {
2520 {
2521 /* You're supposed to have one `template <...>' for every
2522 template class, but you don't need one for a full
2523 specialization. For example:
2525 template <class T> struct S{};
2526 template <> struct S<int> { void f(); };
2527 void S<int>::f () {}
2529 is correct; there shouldn't be a `template <>' for the
2530 definition of `S<int>::f'. */
2532 /* If CTYPE does not have template information of any
2533 kind, then it is not a template, nor is it nested
2534 within a template. */
2542 }
2545 }
2547 /* Do a simple sanity check on the template headers that precede the
2548 variable declaration DECL. */
2550 void
2552 {
2557 {
2560 "variable templates only available with "
2563 // Namespace-scope variable templates should have a template header.
2565 }
2567 {
2569 "too many template headers for %qD "
2575 "members of an explicitly specialized class are defined "
2577 }
2578 }
2580 /* An explicit specialization whose declarator-id or class-head-name is not
2581 qualified shall be declared in the nearest enclosing namespace of the
2582 template, or, if the namespace is inline (7.3.1), any namespace from its
2583 enclosing namespace set.
2585 If the name declared in the explicit instantiation is an unqualified name,
2586 the explicit instantiation shall appear in the namespace where its template
2587 is declared or, if that namespace is inline (7.3.1), any namespace from its
2588 enclosing namespace set. */
2590 void
2592 {
2597 {
2603 /* This was allowed in C++98, so only pedwarn. */
2605 "outside its namespace must use a nested-name-"
2607 }
2608 }
2610 /* Check to see if the function just declared, as indicated in
2611 DECLARATOR, and in DECL, is a specialization of a function
2612 template. We may also discover that the declaration is an explicit
2613 instantiation at this point.
2615 Returns DECL, or an equivalent declaration that should be used
2616 instead if all goes well. Issues an error message if something is
2617 amiss. Returns error_mark_node if the error is not easily
2618 recoverable.
2620 FLAGS is a bitmask consisting of the following flags:
2622 2: The function has a definition.
2623 4: The function is a friend.
2625 The TEMPLATE_COUNT is the number of references to qualifying
2626 template classes that appeared in the name of the function. For
2627 example, in
2629 template <class T> struct S { void f(); };
2630 void S<int>::f();
2632 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2633 classes are not counted in the TEMPLATE_COUNT, so that in
2635 template <class T> struct S {};
2636 template <> struct S<int> { void f(); }
2637 template <> void S<int>::f();
2639 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2640 invalid; there should be no template <>.)
2642 If the function is a specialization, it is marked as such via
2643 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2644 is set up correctly, and it is added to the list of specializations
2645 for that template. */
2647 tree
2649 tree decl,
2652 {
2661 tmpl_spec_kind tsk;
2664 {
2667 else
2669 }
2670 else
2674 {
2677 {
2680 }
2682 {
2684 /* This could be something like:
2686 template <class T> void f(T);
2687 class S { friend void f<>(int); } */
2689 else
2690 {
2691 /* This case handles bogus declarations like template <>
2692 template <class T> void f<int>(); */
2695 declarator);
2697 }
2698 }
2702 /* The error has already been reported in
2703 check_specialization_scope. */
2709 /* Fall through. */
2722 decl);
2725 else
2729 /* Fall through. */
2735 /* In cases like template<> constexpr bool v = true;
2736 We'll give an error in check_template_variable. */
2742 else
2748 {
2749 /* This case handles bogus declarations like template <>
2750 template <class T> void f<int>(); */
2754 declarator);
2756 {
2757 /* Partial specialization of variable template. */
2761 }
2765 else
2769 ok:;
2770 }
2773 /* This is a specialization of a member template, without
2774 specialization the containing class. Something like:
2776 template <class T> struct S {
2777 template <class U> void f (U);
2778 };
2779 template <> template <class U> void S<int>::f(U) {}
2781 That's a specialization -- but of the entire template. */
2787 }
2790 /* This doesn't apply to variable templates. */
2793 {
2797 {
2801 }
2802 }
2805 {
2810 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2812 {
2813 tree fns;
2818 else
2819 {
2820 /* If there is no class context, the explicit instantiation
2821 must be at namespace scope. */
2824 /* Find the namespace binding, using the declaration
2825 context. */
2829 /* If lookup fails, look for a friend declaration so we can
2830 give a better diagnostic. */
2836 {
2839 }
2840 }
2843 }
2849 {
2851 /* A specialization in class scope. This is invalid,
2852 but the error will already have been flagged by
2853 check_specialization_scope. */
2855 else
2856 {
2857 /* It's not valid to write an explicit instantiation in
2858 class scope, e.g.:
2860 class C { template void f(); }
2862 This case is caught by the parser. However, on
2863 something like:
2865 template class C { void f(); };
2867 (which is invalid) we can get here. The error will be
2868 issued later. */
2869 ;
2870 }
2873 }
2876 {
2877 // We'll match variable templates in start_decl.
2881 /* Find the list of functions in ctype that have the same
2882 name as the declared function. */
2886 {
2890 {
2891 /* From [temp.expl.spec]:
2893 If such an explicit specialization for the member
2894 of a class template names an implicitly-declared
2895 special member function (clause _special_), the
2896 program is ill-formed.
2898 Similar language is found in [temp.explicit]. */
2901 }
2904 }
2906 /* For a type-conversion operator, We might be looking for
2907 `operator int' which will be a specialization of
2908 `operator T'. Grab all the conversion operators, and
2909 then select from them. */
2914 {
2917 }
2918 else
2920 }
2922 /* Figure out what exactly is being specialized at this point.
2923 Note that for an explicit instantiation, even one for a
2924 member function, we cannot tell a priori whether the
2925 instantiation is for a member template, or just a member
2926 function of a template class. Even if a member template is
2927 being instantiated, the member template arguments may be
2928 elided if they can be deduced from the rest of the
2929 declaration. */
2932 member_specialization,
2933 template_count,
2934 tsk);
2937 /* We couldn't figure out what this declaration was
2938 specializing. */
2940 else
2941 {
2944 {
2946 "friend declaration %qD is not visible to "
2950 }
2958 {
2959 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
2960 is done by do_decl_instantiation later. */
2966 {
2967 /* If TMPL is not the most general template (for
2968 example, if TMPL is a friend template that is
2969 injected into namespace scope), then there will
2970 be too many levels of TARGS. Remove some of them
2971 here. */
2973 tree new_targs;
2980 }
2983 }
2985 /* If we thought that the DECL was a member function, but it
2986 turns out to be specializing a static member function,
2987 make DECL a static member function as well. */
2993 /* If this is a specialization of a member template of a
2994 template class, we want to return the TEMPLATE_DECL, not
2995 the specialization of it. */
2997 {
3002 {
3003 tree parm;
3007 /* We want to use the argument list specified in the
3008 definition, not in the original declaration. */
3013 }
3016 }
3018 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3024 /* Inherit default function arguments from the template
3025 DECL is specializing. */
3029 /* This specialization has the same protection as the
3030 template it specializes. */
3034 /* 7.1.1-1 [dcl.stc]
3036 A storage-class-specifier shall not be specified in an
3037 explicit specialization...
3039 The parser rejects these, so unless action is taken here,
3040 explicit function specializations will always appear with
3041 global linkage.
3043 The action recommended by the C++ CWG in response to C++
3044 defect report 605 is to make the storage class and linkage
3045 of the explicit specialization match the templated function:
3047 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3048 */
3050 {
3054 /* A concept cannot be specialized. */
3056 {
3058 gen_tmpl);
3060 }
3062 /* This specialization has the same linkage and visibility as
3063 the function template it specializes. */
3066 {
3069 }
3072 {
3075 }
3076 }
3078 /* If DECL is a friend declaration, declared using an
3079 unqualified name, the namespace associated with DECL may
3080 have been set incorrectly. For example, in:
3082 template <typename T> void f(T);
3083 namespace N {
3084 struct S { friend void f<int>(int); }
3085 }
3087 we will have set the DECL_CONTEXT for the friend
3088 declaration to N, rather than to the global namespace. */
3093 /* This is not really a declaration of a specialization.
3094 It's just the name of an instantiation. But, it's not
3095 a request for an instantiation, either. */
3098 /* A specialization is not necessarily COMDAT. */
3104 /* If this is a full specialization, register it so that we can find
3105 it again. Partial specializations will be registered in
3106 process_partial_specialization. */
3111 /* A 'structor should already have clones. */
3117 }
3118 }
3121 }
3123 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3124 parameters. These are represented in the same format used for
3125 DECL_TEMPLATE_PARMS. */
3127 int
3129 {
3130 const_tree p1;
3131 const_tree p2;
3139 {
3151 {
3155 /* If either of the template parameters are invalid, assume
3156 they match for the sake of error recovery. */
3169 }
3170 }
3173 /* One set of parameters has more parameters lists than the
3174 other. */
3178 }
3180 /* Determine whether PARM is a parameter pack. */
3182 bool
3184 {
3185 /* Determine if we have a non-type template parameter pack. */
3192 /* If this is a list of template parameters, we could get a
3193 TYPE_DECL or a TEMPLATE_DECL. */
3197 /* Otherwise it must be a type template parameter. */
3201 }
3203 /* Determine if T is a function parameter pack. */
3205 bool
3207 {
3211 }
3213 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3214 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3216 tree
3218 {
3225 }
3227 /* Return true iff the function parameter PARAM_DECL was expanded
3228 from the function parameter pack PACK. */
3230 bool
3232 {
3237 /* The parameter pack and its pack arguments have the same
3238 DECL_PARM_INDEX. */
3240 }
3242 /* Determine whether ARGS describes a variadic template args list,
3243 i.e., one that is terminated by a template argument pack. */
3245 static bool
3247 {
3249 tree last_parm;
3263 }
3265 /* Generate a new name for the parameter pack name NAME (an
3266 IDENTIFIER_NODE) that incorporates its */
3268 static tree
3270 {
3271 /* Munge the name to include the parameter index. */
3272 #define NUMBUF_LEN 128
3286 }
3288 /* Return true if T is a primary function, class or alias template
3289 instantiation. */
3291 bool
3293 {
3307 }
3309 /* Return true if PARM is a template template parameter. */
3311 bool
3313 {
3315 }
3317 /* Return true iff PARM is a DECL representing a type template
3318 parameter. */
3320 bool
3322 {
3327 }
3329 /* Return the template parameters of T if T is a
3330 primary template instantiation, NULL otherwise. */
3332 tree
3334 {
3339 parms = INNERMOST_TEMPLATE_PARMS
3343 }
3345 /* Return the template parameters of the LEVELth level from the full list
3346 of template parameters PARMS. */
3348 tree
3350 {
3351 tree p;
3362 }
3364 /* Returns the template arguments of T if T is a template instantiation,
3365 NULL otherwise. */
3367 tree
3369 {
3377 }
3379 /* Return the argument pack elements of T if T is a template argument pack,
3380 NULL otherwise. */
3382 tree
3384 {
3390 }
3392 /* True iff FN is a function representing a built-in variadic parameter
3393 pack. */
3395 bool
3397 {
3407 }
3409 /* True iff CALL is a call to a function representing a built-in variadic
3410 parameter pack. */
3412 static bool
3414 {
3418 }
3420 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3422 static tree
3424 tree in_decl)
3425 {
3431 {
3433 {
3436 }
3441 }
3442 else
3443 {
3447 /* Calculate the largest value of len that won't make the size of the vec
3448 overflow an int. The compiler will exceed resource limits long before
3449 this, but it seems a decent place to diagnose. */
3453 {
3458 }
3466 }
3467 }
3469 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3470 CALL. */
3472 static tree
3474 tree in_decl)
3475 {
3485 }
3487 /* Structure used to track the progress of find_parameter_packs_r. */
3488 struct find_parameter_pack_data
3489 {
3490 /* TREE_LIST that will contain all of the parameter packs found by
3491 the traversal. */
3494 /* Set of AST nodes that have been visited by the traversal. */
3497 /* True iff we're making a type pack expansion. */
3499 };
3501 /* Identifies all of the argument packs that occur in a template
3502 argument and appends them to the TREE_LIST inside DATA, which is a
3503 find_parameter_pack_data structure. This is a subroutine of
3504 make_pack_expansion and uses_parameter_packs. */
3505 static tree
3507 {
3513 /* Handle type aliases/typedefs. */
3515 {
3522 }
3524 /* Identify whether this is a parameter pack or not. */
3526 {
3534 /* FALLTHRU */
3536 /* If the placeholder appears in the decl-specifier-seq of a function
3537 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3538 is a pack expansion, the invented template parameter is a template
3539 parameter pack. */
3549 {
3550 /* We don't want to walk into the type of a PARM_DECL,
3551 because we don't want to see the type parameter pack. */
3554 }
3557 /* Look through a lambda capture proxy to the field pack. */
3560 {
3566 }
3568 {
3570 find_parameter_packs_r,
3573 }
3585 /* Not a parameter pack. */
3587 }
3590 {
3591 /* Add this parameter pack to the list. */
3593 }
3599 /* This switch statement will return immediately if we don't find a
3600 parameter pack. */
3602 {
3607 /* Check the template itself. */
3610 /* Check the template arguments. */
3624 /* Ignore the declaration of a capture proxy for a parameter pack. */
3632 /* Fall through. */
3677 {
3683 }
3686 {
3687 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3688 type_pack_expansion_p to false so that any placeholders
3689 within the expression don't get marked as parameter packs. */
3697 }
3701 }
3704 }
3706 /* Determines if the expression or type T uses any parameter packs. */
3707 bool
3709 {
3718 }
3720 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3721 representation a base-class initializer into a parameter pack
3722 expansion. If all goes well, the resulting node will be an
3723 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3724 respectively. */
3725 tree
3727 {
3728 tree result;
3737 {
3738 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3739 class initializer. In this case, the TREE_PURPOSE will be a
3740 _TYPE node (representing the base class expansion we're
3741 initializing) and the TREE_VALUE will be a TREE_LIST
3742 containing the initialization arguments.
3744 The resulting expansion looks somewhat different from most
3745 expansions. Rather than returning just one _EXPANSION, we
3746 return a TREE_LIST whose TREE_PURPOSE is a
3747 TYPE_PACK_EXPANSION containing the bases that will be
3748 initialized. The TREE_VALUE will be identical to the
3749 original TREE_VALUE, which is a list of arguments that will
3750 be passed to each base. We do not introduce any new pack
3751 expansion nodes into the TREE_VALUE (although it is possible
3752 that some already exist), because the TREE_PURPOSE and
3753 TREE_VALUE all need to be expanded together with the same
3754 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3755 resulting TREE_PURPOSE will mention the parameter packs in
3756 both the bases and the arguments to the bases. */
3757 tree purpose;
3758 tree value;
3761 /* Determine which parameter packs will be used by the base
3762 class expansion. */
3771 {
3775 }
3778 {
3779 /* Collect the sets of parameter packs used in each of the
3780 initialization arguments. */
3782 {
3783 /* Determine which parameter packs will be expanded in this
3784 argument. */
3787 }
3788 }
3792 /* Create the pack expansion type for the base type. */
3798 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3799 they will rarely be compared to anything. */
3803 }
3808 /* Build the PACK_EXPANSION_* node. */
3809 result = for_types
3814 {
3815 /* Propagate type and const-expression information. */
3818 /* Mark this read now, since the expansion might be length 0. */
3820 }
3821 else
3822 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3823 they will rarely be compared to anything. */
3826 /* Determine which parameter packs will be expanded. */
3833 /* Make sure we found some parameter packs. */
3835 {
3838 else
3841 }
3847 }
3849 /* Checks T for any "bare" parameter packs, which have not yet been
3850 expanded, and issues an error if any are found. This operation can
3851 only be done on full expressions or types (e.g., an expression
3852 statement, "if" condition, etc.), because we could have expressions like:
3854 foo(f(g(h(args)))...)
3856 where "args" is a parameter pack. check_for_bare_parameter_packs
3857 should not be called for the subexpressions args, h(args),
3858 g(h(args)), or f(g(h(args))), because we would produce erroneous
3859 error messages.
3861 Returns TRUE and emits an error if there were bare parameter packs,
3862 returns FALSE otherwise. */
3863 bool
3865 {
3872 /* A lambda might use a parameter pack from the containing context. */
3886 {
3890 {
3901 else
3906 else
3910 }
3913 }
3916 }
3918 /* Expand any parameter packs that occur in the template arguments in
3919 ARGS. */
3920 tree
3922 {
3931 /* First, determine if we need to expand anything, and the number of
3932 slots we'll need. */
3934 {
3939 {
3943 else
3945 }
3946 else
3947 {
3949 num_result_args++;
3950 }
3951 }
3953 /* If no expansion is necessary, we're done. */
3957 /* Expand arguments. */
3960 non_default_args_count =
3963 {
3966 {
3973 }
3974 else
3975 {
3978 }
3979 }
3983 }
3985 /* Checks if DECL shadows a template parameter.
3987 [temp.local]: A template-parameter shall not be redeclared within its
3988 scope (including nested scopes).
3990 Emits an error and returns TRUE if the DECL shadows a parameter,
3991 returns FALSE otherwise. */
3993 bool
3995 {
3996 tree olddecl;
3998 /* If we're not in a template, we can't possibly shadow a template
3999 parameter. */
4003 /* Figure out what we're shadowing. */
4007 /* If there's no previous binding for this name, we're not shadowing
4008 anything, let alone a template parameter. */
4012 /* If we're not shadowing a template parameter, we're done. Note
4013 that OLDDECL might be an OVERLOAD (or perhaps even an
4014 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4015 node. */
4019 /* We check for decl != olddecl to avoid bogus errors for using a
4020 name inside a class. We check TPFI to avoid duplicate errors for
4021 inline member templates. */
4027 /* Don't complain about the injected class name, as we've already
4028 complained about the class itself. */
4035 else
4040 }
4042 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4043 ORIG_LEVEL, DECL, and TYPE. */
4045 static tree
4049 tree decl,
4050 tree type)
4051 {
4062 }
4064 /* Find the canonical type parameter for the given template type
4065 parameter. Returns the canonical type parameter, which may be TYPE
4066 if no such parameter existed. */
4068 static tree
4070 {
4071 tree list;
4085 else
4086 {
4090 }
4091 }
4093 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4094 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4095 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4096 new one is created. */
4098 static tree
4100 tsubst_flags_t complain)
4101 {
4106 {
4125 /* Template template parameters need this. */
4127 {
4134 }
4135 }
4138 }
4140 /* Process information from new template parameter PARM and append it
4141 to the LIST being built. This new parameter is a non-type
4142 parameter iff IS_NON_TYPE is true. This new parameter is a
4143 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4144 is in PARM_LOC. */
4146 tree
4149 {
4158 {
4162 {
4166 else
4168 }
4171 }
4174 {
4180 {
4181 /* [temp.param]
4183 The top-level cv-qualifiers on the template-parameter are
4184 ignored when determining its type. */
4189 && !is_parameter_pack
4190 /* If we're in a nested template parameter list, the template
4191 template parameter could be a parameter pack. */
4193 {
4194 /* This template parameter is not a parameter pack, but it
4195 should be. Complain about "bare" parameter packs. */
4198 /* Recover by calling this a parameter pack. */
4200 }
4201 }
4203 /* A template parameter is not modifiable. */
4212 processing_template_decl,
4217 }
4218 else
4219 {
4220 tree t;
4224 {
4226 /* This is for distinguishing between real templates and template
4227 template parameters */
4231 }
4232 else
4233 {
4235 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4238 }
4245 processing_template_decl,
4249 }
4253 /* Build requirements for the type/template parameter.
4254 This must be done after SET_DECL_TEMPLATE_PARM_P or
4255 process_template_parm could fail. */
4260 /* Build the parameter node linking the parameter declaration,
4261 its default argument (if any), and its constraints (if any). */
4266 }
4268 /* The end of a template parameter list has been reached. Process the
4269 tree list into a parameter vector, converting each parameter into a more
4270 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4271 as PARM_DECLs. */
4273 tree
4275 {
4280 /* Pop the dummy parameter level and add the real one. */
4283 current_template_parms
4288 {
4292 }
4297 }
4299 // Explicitly indicate the end of the template parameter list. We assume
4300 // that the current template parameters have been constructed and/or
4301 // managed explicitly, as when creating new template template parameters
4302 // from a shorthand constraint.
4303 void
4305 {
4307 }
4309 /* end_template_decl is called after a template declaration is seen. */
4311 void
4313 {
4319 /* This matches the pushlevel in begin_template_parm_list. */
4324 }
4326 /* Takes a TREE_LIST representing a template parameter and convert it
4327 into an argument suitable to be passed to the type substitution
4328 functions. Note that If the TREE_LIST contains an error_mark
4329 node, the returned argument is error_mark_node. */
4331 tree
4333 {
4346 {
4350 {
4351 /* Turn this argument into a TYPE_ARGUMENT_PACK
4352 with a single element, which expands T. */
4361 }
4362 }
4363 else
4364 {
4368 {
4369 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4370 with a single element, which expands T. */
4380 }
4381 else
4383 }
4385 }
4387 /* Given a single level of template parameters (a TREE_VEC), return it
4388 as a set of template arguments. */
4390 static tree
4392 {
4402 }
4404 /* Given a set of template parameters, return them as a set of template
4405 arguments. The template parameters are represented as a TREE_VEC, in
4406 the form documented in cp-tree.h for template arguments. */
4408 static tree
4410 {
4411 tree header;
4416 /* If there is only one level of template parameters, we do not
4417 create a TREE_VEC of TREE_VECs. Instead, we return a single
4418 TREE_VEC containing the arguments. */
4423 {
4428 else
4430 }
4433 }
4435 /* Within the declaration of a template, return the currently active
4436 template parameters as an argument TREE_VEC. */
4438 static tree
4440 {
4442 }
4444 /* Update the declared TYPE by doing any lookups which were thought to be
4445 dependent, but are not now that we know the SCOPE of the declarator. */
4447 tree
4449 {
4460 /* Don't bother building up the args in this case. */
4462 {
4463 /* tsubst in the args corresponding to the template parameters,
4464 including auto if present. Most things will be unchanged, but
4465 make_typename_type and tsubst_qualified_id will resolve
4466 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4469 tree pushed;
4471 {
4475 }
4480 }
4486 {
4489 else
4491 }
4493 }
4495 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4496 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4497 the new template is a member template. */
4499 tree
4501 {
4509 }
4511 struct template_parm_data
4512 {
4513 /* The level of the template parameters we are currently
4514 processing. */
4517 /* The index of the specialization argument we are currently
4518 processing. */
4521 /* An array whose size is the number of template parameters. The
4522 elements are nonzero if the parameter has been used in any one
4523 of the arguments processed so far. */
4526 /* An array whose size is the number of template arguments. The
4527 elements are nonzero if the argument makes use of template
4528 parameters of this level. */
4530 };
4532 /* Subroutine of push_template_decl used to see if each template
4533 parameter in a partial specialization is used in the explicit
4534 argument list. If T is of the LEVEL given in DATA (which is
4535 treated as a template_parm_data*), then DATA->PARMS is marked
4536 appropriately. */
4538 static int
4540 {
4548 {
4551 }
4553 /* In C++17 the type of a non-type argument is a deduced context. */
4558 data,
4559 NULL,
4562 /* Return zero so that for_each_template_parm will continue the
4563 traversal of the tree; we want to mark *every* template parm. */
4565 }
4567 /* Process the partial specialization DECL. */
4569 static tree
4571 {
4578 tree inner_parms;
4579 tree inst;
4589 /* A concept cannot be specialized. */
4591 {
4594 }
4599 /* We check that each of the template parameters given in the
4600 partial specialization is used in the argument list to the
4601 specialization. For example:
4603 template <class T> struct S;
4604 template <class T> struct S<T*>;
4606 The second declaration is OK because `T*' uses the template
4607 parameter T, whereas
4609 template <class T> struct S<int>;
4611 is no good. Even trickier is:
4613 template <class T>
4614 struct S1
4615 {
4616 template <class U>
4617 struct S2;
4618 template <class U>
4619 struct S2<T>;
4620 };
4622 The S2<T> declaration is actually invalid; it is a
4623 full-specialization. Of course,
4625 template <class U>
4626 struct S2<T (*)(U)>;
4628 or some such would have been OK. */
4636 {
4641 NULL,
4643 }
4646 {
4647 /* One of the template parms was not used in a deduced context in the
4648 specialization. */
4650 {
4654 }
4658 }
4663 /* [temp.class.spec]
4665 The argument list of the specialization shall not be identical to
4666 the implicit argument list of the primary template. */
4667 tree main_args
4670 && (!flag_concepts
4673 {
4677 else
4681 }
4683 /* A partial specialization that replaces multiple parameters of the
4684 primary template with a pack expansion is less specialized for those
4685 parameters. */
4687 {
4689 "primary template because it replaces multiple parameters "
4692 /* Avoid crash in process_partial_specialization. */
4694 }
4696 /* If we aren't in a dependent class, we can actually try deduction. */
4698 /* FIXME we should be able to handle a partial specialization of a
4699 partial instantiation, but currently we can't (c++/41727). */
4702 {
4706 maintmpl);
4707 }
4709 /* [temp.class.spec]
4711 A partially specialized non-type argument expression shall not
4712 involve template parameters of the partial specialization except
4713 when the argument expression is a simple identifier.
4715 The type of a template parameter corresponding to a specialized
4716 non-type argument shall not be dependent on a parameter of the
4717 specialization.
4719 Also, we verify that pack expansions only occur at the
4720 end of the argument list. */
4724 {
4731 {
4732 /* Extract the arguments from the argument pack. We'll be
4733 iterating over these in the following loop. */
4736 }
4739 {
4741 /* Get the Jth argument in the parameter pack. */
4745 {
4746 /* Pack expansions must come at the end of the
4747 argument list. */
4750 {
4754 else
4757 }
4758 }
4761 /* We only care about the pattern. */
4767 /* This next two lines are the `argument expression is not just a
4768 simple identifier' condition and also the `specialized
4769 non-type argument' bit. */
4773 {
4777 arg);
4778 else
4779 {
4780 /* Look at the corresponding template parameter,
4781 marking which template parameters its type depends
4782 upon. */
4786 {
4787 /* We haven't yet initialized TPD2. Do so now. */
4789 /* The number of parameters here is the number in the
4790 main template, which, as checked in the assertion
4791 above, is NARGS. */
4795 }
4797 /* Mark the template parameters. But this time, we're
4798 looking for the template parameters of the main
4799 template, not in the specialization. */
4806 NULL,
4810 {
4811 /* The type depended on some template parameters.
4812 If they are fully specialized in the
4813 specialization, that's OK. */
4822 "type %qT of template argument %qE depends "
4824 "type %qT of template argument %qE depends "
4826 type,
4827 arg);
4828 }
4829 }
4830 }
4831 }
4832 }
4834 /* We should only get here once. */
4838 // Build the template decl.
4847 /* Give template template parms a DECL_CONTEXT of the template
4848 for which they are a parameter. */
4850 {
4854 }
4857 /* We didn't register this in check_explicit_specialization so we could
4858 wait until the constraints were set. */
4860 else
4870 {
4876 {
4884 "declaration of %qD ambiguates earlier template "
4888 "partial specialization of %qD after instantiation "
4890 }
4891 }
4894 }
4896 /* PARM is a template parameter of some form; return the corresponding
4897 TEMPLATE_PARM_INDEX. */
4899 static tree
4901 {
4914 }
4916 /* Subroutine of fixed_parameter_pack_p below. Look for any template
4917 parameter packs used by the template parameter PARM. */
4919 static void
4921 {
4922 /* A type parm can't refer to another parm. */
4926 {
4930 }
4937 }
4939 /* PARM is a template parameter pack. Return any parameter packs used in
4940 its type or the type of any of its template parameters. If there are
4941 any such packs, it will be instantiated into a fixed template parameter
4942 list by partial instantiation rather than be fully deduced. */
4944 tree
4946 {
4947 /* This can only be true in a member template. */
4950 /* This can only be true for a parameter pack. */
4953 /* A type parm can't refer to another parm. */
4967 }
4969 /* Check that a template declaration's use of default arguments and
4970 parameter packs is not invalid. Here, PARMS are the template
4971 parameters. IS_PRIMARY is true if DECL is the thing declared by
4972 a primary template. IS_PARTIAL is true if DECL is a partial
4973 specialization.
4975 IS_FRIEND_DECL is nonzero if DECL is a friend function template
4976 declaration (but not a definition); 1 indicates a declaration, 2
4977 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4978 emitted for extraneous default arguments.
4980 Returns TRUE if there were no errors found, FALSE otherwise. */
4982 bool
4985 {
4988 tree parm_level;
4991 /* [temp.param]
4993 A default template-argument shall not be specified in a
4994 function template declaration or a function template definition, nor
4995 in the template-parameter-list of the definition of a member of a
4996 class template. */
5000 /* You can't have a function template declaration in a local
5001 scope, nor you can you define a member of a class template in a
5002 local scope. */
5010 /* A lambda doesn't have an explicit declaration; don't complain
5011 about the parms of the enclosing class. */
5018 /* If this is either a friend defined in the scope of the class
5019 or a member function. */
5025 /* And, if it was a member function, it really was defined in
5026 the scope of the class. */
5029 /* We already checked these parameters when the template was
5030 declared, so there's no need to do it again now. This function
5031 was defined in class scope, but we're processing its body now
5032 that the class is complete. */
5035 /* Core issue 226 (C++0x only): the following only applies to class
5036 templates. */
5039 {
5040 /* [temp.param]
5042 If a template-parameter has a default template-argument, all
5043 subsequent template-parameters shall have a default
5044 template-argument supplied. */
5046 {
5053 {
5063 {
5065 /* For better subsequent error-recovery, we indicate that
5066 there should have been a default argument. */
5069 }
5071 && !is_friend_decl
5072 /* Don't complain about an enclosing partial
5073 specialization. */
5078 /* A fixed parameter pack will be partially
5079 instantiated into a fixed length list. */
5081 {
5082 /* A primary class template can only have one
5083 parameter pack, at the end of the template
5084 parameter list. */
5092 }
5093 }
5094 }
5095 }
5098 || is_partial
5099 || !is_primary
5101 /* For an ordinary class template, default template arguments are
5102 allowed at the innermost level, e.g.:
5103 template <class T = int>
5104 struct S {};
5105 but, in a partial specialization, they're not allowed even
5106 there, as we have in [temp.class.spec]:
5108 The template parameter list of a specialization shall not
5109 contain default template argument values.
5111 So, for a partial specialization, or for a function template
5112 (in C++98/C++03), we look at all of them. */
5113 ;
5114 else
5115 /* But, for a primary class template that is not a partial
5116 specialization we look at all template parameters except the
5117 innermost ones. */
5120 /* Figure out what error message to issue. */
5135 else
5136 /* Per [temp.param]/9, "A default template-argument shall not be
5137 specified in the template-parameter-lists of the definition of
5138 a member of a class template that appears outside of the member's
5139 class.", thus if we aren't handling a member of a class template
5140 there is no need to examine the parameters. */
5144 /* If we're inside a class definition, there's no need to
5145 examine the parameters to the class itself. On the one
5146 hand, they will be checked when the class is defined, and,
5147 on the other, default arguments are valid in things like:
5148 template <class T = double>
5149 struct S { template <class U> void f(U); };
5150 Here the default argument for `S' has no bearing on the
5151 declaration of `f'. */
5153 else
5154 /* Check everything. */
5160 {
5167 {
5172 {
5174 {
5181 }
5183 /* Clear out the default argument so that we are not
5184 confused later. */
5186 }
5187 }
5189 /* At this point, if we're still interested in issuing messages,
5190 they must apply to classes surrounding the object declared. */
5194 }
5197 }
5199 /* Worker for push_template_decl_real, called via
5200 for_each_template_parm. DATA is really an int, indicating the
5201 level of the parameters we are interested in. If T is a template
5202 parameter of that level, return nonzero. */
5204 static int
5206 {
5212 else
5215 }
5217 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5218 DATA is really an int, indicating the innermost outer level of parameters.
5219 If T is a template parameter of that level or further out, return
5220 nonzero. */
5222 static int
5224 {
5230 else
5233 }
5235 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5236 parameters given by current_template_args, or reuses a
5237 previously existing one, if appropriate. Returns the DECL, or an
5238 equivalent one, if it is replaced via a call to duplicate_decls.
5240 If IS_FRIEND is true, DECL is a friend declaration. */
5242 tree
5244 {
5245 tree tmpl;
5246 tree args;
5247 tree info;
5248 tree ctx;
5252 /* True if the template is a member template, in the sense of
5253 [temp.mem]. */
5259 /* See if this is a partial specialization. */
5272 /* For a friend, we want the context of the friend function, not
5273 the type of which it is a friend. */
5277 /* In the case of a virtual function, we want the class in which
5278 it is defined. */
5280 else
5281 /* Otherwise, if we're currently defining some class, the DECL
5282 is assumed to be a member of the class. */
5291 /* See if this is a primary template. */
5294 /* A friend template that specifies a class context, i.e.
5295 template <typename T> friend void A<T>::f();
5296 is not primary. */
5301 else
5305 {
5312 {
5315 }
5317 {
5319 {
5322 }
5324 {
5325 /* [temp.mem]
5327 A destructor shall not be a member template. */
5330 }
5337 {
5338 /* [basic.stc.dynamic.allocation]
5340 An allocation function can be a function
5341 template. ... Template allocation functions shall
5342 have two or more parameters. */
5345 }
5346 }
5349 {
5350 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5353 {
5359 }
5360 }
5363 /* alias-declaration */
5367 else
5368 {
5371 }
5372 }
5374 /* Check to see that the rules regarding the use of default
5375 arguments are not being violated. */
5379 /* Ensure that there are no parameter packs in the type of this
5380 declaration that have not been expanded. */
5382 {
5383 /* Check each of the arguments individually to see if there are
5384 any bare parameter packs. */
5390 {
5393 {
5394 /* This is a PARM_DECL that contains unexpanded parameter
5395 packs. We have already complained about this in the
5396 check_for_bare_parameter_packs call, so just replace
5397 these types with ERROR_MARK_NODE. */
5400 }
5404 }
5406 /* Check for bare parameter packs in the return type and the
5407 exception specifiers. */
5409 /* Errors were already issued, set return type to int
5410 as the frontend doesn't expect error_mark_node as
5411 the return type. */
5415 }
5420 {
5423 }
5436 {
5441 /* If DECL is a TYPE_DECL for a class-template, then there won't
5442 be DECL_LANG_SPECIFIC. The information equivalent to
5443 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5447 {
5448 /* Since a template declaration already existed for this
5449 class-type, we must be redeclaring it here. Make sure
5450 that the redeclaration is valid. */
5452 current_template_parms,
5454 /* We don't need to create a new TEMPLATE_DECL; just use the
5455 one we already had. */
5457 }
5458 else
5459 {
5461 member_template_p);
5466 {
5467 /* A specialization of a member template of a template
5468 class. */
5472 }
5473 }
5474 }
5475 else
5476 {
5482 {
5485 }
5493 {
5494 tree new_tmpl;
5496 /* The declaration is a specialization of a member
5497 template, declared outside the class. Therefore, the
5498 innermost template arguments will be NULL, so we
5499 replace them with the arguments determined by the
5500 earlier call to check_explicit_specialization. */
5503 new_tmpl
5505 member_template_p);
5515 args,
5518 }
5520 /* Make sure the template headers we got make sense. */
5525 {
5530 }
5531 else
5533 {
5538 {
5542 else
5546 /* Avoid crash in import_export_decl. */
5549 }
5554 /* Can happen in erroneous input. */
5556 else
5558 }
5560 /* Check that the parms are used in the appropriate qualifying scopes
5561 in the declarator. */
5565 {
5571 /* Avoid crash in import_export_decl. */
5574 }
5575 }
5580 /* Push template declarations for global functions and types. Note
5581 that we do not try to push a global template friend declared in a
5582 template class; such a thing may well depend on the template
5583 parameters of the class. */
5586 {
5591 /* Hide template friend classes that haven't been declared yet. */
5593 {
5596 }
5597 }
5600 {
5605 /* Give template template parms a DECL_CONTEXT of the template
5606 for which they are a parameter. */
5609 {
5613 }
5619 }
5621 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5622 back to its most general template. If TMPL is a specialization,
5623 ARGS may only have the innermost set of arguments. Add the missing
5624 argument levels if necessary. */
5632 else
5633 {
5638 }
5641 && !is_friend
5644 /* Set DECL_COMDAT on template instantiations; if we force
5645 them to be emitted by explicit instantiation or -frepo,
5646 mark_needed will tell cgraph to do the right thing. */
5650 }
5652 tree
5654 {
5656 }
5658 /* FN is an inheriting constructor that inherits from the constructor
5659 template INHERITED; turn FN into a constructor template with a matching
5660 template header. */
5662 tree
5664 {
5665 tree inner_parms
5668 tree parms
5679 }
5681 /* Called when a class template TYPE is redeclared with the indicated
5682 template PARMS, e.g.:
5684 template <class T> struct S;
5685 template <class T> struct S {}; */
5687 bool
5689 {
5690 tree tmpl;
5691 tree tmpl_parms;
5695 {
5698 }
5702 /* The type is nested in some template class. Nothing to worry
5703 about here; there are no new template parameters for the nested
5704 type. */
5708 {
5710 tmpl);
5712 }
5718 {
5728 }
5731 {
5732 tree tmpl_parm;
5733 tree parm;
5734 tree tmpl_default;
5735 tree parm_default;
5749 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5750 TEMPLATE_DECL. */
5760 {
5764 }
5767 {
5768 /* We have in [temp.param]:
5770 A template-parameter may not be given default arguments
5771 by two different declarations in the same scope. */
5776 }
5779 /* Update the previous template parameters (which are the ones
5780 that will really count) with the new default value. */
5783 /* Update the new parameters, too; they'll be used as the
5784 parameters for any members. */
5787 /* Give each template template parm in this redeclaration a
5788 DECL_CONTEXT of the template for which they are a parameter. */
5790 {
5793 }
5797 }
5799 // Cannot redeclare a class template with a different set of constraints.
5801 {
5806 }
5809 }
5811 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5812 to be used when the caller has already checked
5813 (processing_template_decl
5814 && !instantiation_dependent_expression_p (expr)
5815 && potential_constant_expression (expr))
5816 and cleared processing_template_decl. */
5818 tree
5820 {
5823 complain,
5827 }
5829 /* Simplify EXPR if it is a non-dependent expression. Returns the
5830 (possibly simplified) expression. */
5832 tree
5834 {
5838 /* If we're in a template, but EXPR isn't value dependent, simplify
5839 it. We're supposed to treat:
5841 template <typename T> void f(T[1 + 1]);
5842 template <typename T> void f(T[2]);
5844 as two declarations of the same function, for example. */
5847 {
5848 processing_template_decl_sentinel s;
5850 }
5852 }
5854 tree
5856 {
5858 }
5860 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
5861 an uninstantiated expression. */
5863 tree
5865 {
5869 {
5872 else
5873 {
5874 processing_template_decl_sentinel s;
5876 }
5877 }
5879 }
5881 /* True iff T is a specialization of a variable template. */
5883 bool
5885 {
5890 }
5892 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5893 template declaration, or a TYPE_DECL for an alias declaration. */
5895 bool
5897 {
5905 }
5907 /* Return TRUE iff T is a specialization of an alias template. */
5909 bool
5911 {
5912 /* It's an alias template specialization if it's an alias and its
5913 TYPE_NAME is a specialization of a primary template. */
5919 }
5921 /* An alias template is complex from a SFINAE perspective if a template-id
5922 using that alias can be ill-formed when the expansion is not, as with
5923 the void_t template. We determine this by checking whether the
5924 expansion for the alias template uses all its template parameters. */
5926 struct uses_all_template_parms_data
5927 {
5930 };
5932 static int
5934 {
5942 }
5944 static bool
5946 {
5961 }
5963 /* Return TRUE iff T is a specialization of a complex alias template with
5964 dependent template-arguments. */
5966 bool
5968 {
5981 }
5983 /* Return the number of innermost template parameters in TMPL. */
5985 static int
5987 {
5990 }
5992 /* Return either TMPL or another template that it is equivalent to under DR
5993 1286: An alias that just changes the name of a template is equivalent to
5994 the other template. */
5996 static tree
5998 {
6001 {
6002 /* Determine if the alias is equivalent to an underlying template. */
6014 tree alias_args = INNERMOST_TEMPLATE_ARGS
6019 /* Alias is equivalent. Strip it and repeat. */
6021 }
6024 }
6026 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6027 must be a reference-to-function or a pointer-to-function type, as specified
6028 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6029 and check that the resulting function has external linkage. */
6031 static tree
6033 tsubst_flags_t complain)
6034 {
6037 linkage_kind linkage;
6052 /* [temp.arg.nontype]/1
6054 A template-argument for a non-type, non-template template-parameter
6055 shall be one of:
6056 [...]
6057 -- the address of an object or function with external [C++11: or
6058 internal] linkage. */
6061 {
6063 {
6069 else
6072 }
6074 }
6078 {
6080 {
6085 else
6089 }
6091 }
6093 accept:
6100 }
6102 /* Subroutine of convert_nontype_argument.
6103 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6104 Emit an error otherwise. */
6106 static bool
6108 tsubst_flags_t complain)
6109 {
6126 {
6131 else
6133 }
6135 }
6137 /* Returns TRUE iff the address of OP is value-dependent.
6139 14.6.2.4 [temp.dep.temp]:
6140 A non-integral non-type template-argument is dependent if its type is
6141 dependent or it has either of the following forms
6142 qualified-id
6143 & qualified-id
6144 and contains a nested-name-specifier which specifies a class-name that
6145 names a dependent type.
6147 We generalize this to just say that the address of a member of a
6148 dependent class is value-dependent; the above doesn't cover the
6149 address of a static data member named with an unqualified-id. */
6151 static bool
6153 {
6154 /* We could use get_inner_reference here, but there's no need;
6155 this is only relevant for template non-type arguments, which
6156 can only be expressed as &id-expression. */
6158 {
6162 }
6165 }
6167 /* The next set of functions are used for providing helpful explanatory
6168 diagnostics for failed overload resolution. Their messages should be
6169 indented by two spaces for consistency with the messages in
6170 call.c */
6172 static int
6174 {
6176 }
6178 /* Other failure functions should call this one, to provide a single function
6179 for setting a breakpoint on. */
6181 static int
6183 {
6185 }
6187 static int
6189 {
6194 }
6196 static int
6198 {
6204 }
6206 static int
6208 {
6212 }
6214 static int
6216 {
6219 " template parameter %qD is not a parameter pack, but "
6223 }
6225 static int
6227 {
6230 " template argument %qE does not match "
6234 }
6236 static int
6238 {
6242 }
6244 static int
6246 {
6252 }
6254 static int
6256 {
6258 {
6263 else
6265 " deduced conflicting values for non-type parameter "
6267 }
6269 }
6271 static int
6273 {
6276 " variable-sized array type %qT is not "
6278 arg);
6280 }
6282 static int
6284 {
6288 arg);
6290 }
6292 static int
6294 {
6296 {
6302 else
6307 }
6309 }
6311 static int
6313 {
6315 }
6317 static int
6320 {
6322 }
6324 static int
6327 {
6333 }
6335 static int
6338 {
6341 {
6349 }
6351 }
6353 static int
6355 {
6358 " template parameters of a template template argument are "
6361 }
6363 static int
6365 {
6371 }
6373 static int
6375 {
6380 }
6382 /* Attempt to convert the non-type template parameter EXPR to the
6383 indicated TYPE. If the conversion is successful, return the
6384 converted value. If the conversion is unsuccessful, return
6385 NULL_TREE if we issued an error message, or error_mark_node if we
6386 did not. We issue error messages for out-and-out bad template
6387 parameters, but not simply because the conversion failed, since we
6388 might be just trying to do argument deduction. Both TYPE and EXPR
6389 must be non-dependent.
6391 The conversion follows the special rules described in
6392 [temp.arg.nontype], and it is much more strict than an implicit
6393 conversion.
6395 This function is called twice for each template argument (see
6396 lookup_template_class for a more accurate description of this
6397 problem). This means that we need to handle expressions which
6398 are not valid in a C++ source, but can be created from the
6399 first call (for instance, casts to perform conversions). These
6400 hacks can go away after we fix the double coercion problem. */
6402 static tree
6404 {
6405 tree expr_type;
6409 /* Detect immediately string literals as invalid non-type argument.
6410 This special-case is not needed for correctness (we would easily
6411 catch this later), but only to provide better diagnostic for this
6412 common user mistake. As suggested by DR 100, we do not mention
6413 linkage issues in the diagnostic as this is not the point. */
6414 /* FIXME we're making this OK. */
6416 {
6422 }
6424 /* Add the ADDR_EXPR now for the benefit of
6425 value_dependent_expression_p. */
6428 {
6432 }
6434 /* If we are in a template, EXPR may be non-dependent, but still
6435 have a syntactic, rather than semantic, form. For example, EXPR
6436 might be a SCOPE_REF, rather than the VAR_DECL to which the
6437 SCOPE_REF refers. Preserving the qualifying scope is necessary
6438 so that access checking can be performed when the template is
6439 instantiated -- but here we need the resolved form so that we can
6440 convert the argument. */
6452 /* If the argument is non-dependent, perform any conversions in
6453 non-dependent context as well. */
6461 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6462 to a non-type argument of "nullptr". */
6466 /* In C++11, integral or enumeration non-type template arguments can be
6467 arbitrary constant expressions. Pointer and pointer to
6468 member arguments can be general constant expressions that evaluate
6469 to a null value, but otherwise still need to be of a specific form. */
6471 {
6473 /* A PTRMEM_CST is already constant, and a valid template
6474 argument for a parameter of pointer to member type, we just want
6475 to leave it in that form rather than lower it to a
6479 {
6480 /* C++17: A template-argument for a non-type template-parameter shall
6481 be a converted constant expression (8.20) of the type of the
6482 template-parameter. */
6488 }
6490 {
6495 }
6496 }
6500 else
6503 /* HACK: Due to double coercion, we can get a
6504 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6505 which is the tree that we built on the first call (see
6506 below when coercing to reference to object or to reference to
6507 function). We just strip everything and get to the arg.
6508 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6509 for examples. */
6511 {
6517 {
6518 /* ??? Maybe we could use convert_from_reference here, but we
6519 would need to relax its constraints because the NOP_EXPR
6520 could actually change the type to something more cv-qualified,
6521 and this is not folded by convert_from_reference. */
6526 && (same_type_ignoring_top_level_qualifiers_p
6529 {
6532 }
6533 }
6534 }
6536 /* [temp.arg.nontype]/5, bullet 1
6538 For a non-type template-parameter of integral or enumeration type,
6539 integral promotions (_conv.prom_) and integral conversions
6540 (_conv.integral_) are applied. */
6542 {
6544 {
6549 }
6554 /* Notice that there are constant expressions like '4 % 0' which
6555 do not fold into integer constants. */
6558 {
6560 {
6564 else
6570 /* else cxx_constant_value complained but gave us
6571 a real constant, so go ahead. */
6573 }
6574 else
6576 }
6578 /* Avoid typedef problems. */
6581 }
6582 /* [temp.arg.nontype]/5, bullet 2
6584 For a non-type template-parameter of type pointer to object,
6585 qualification conversions (_conv.qual_) and the array-to-pointer
6586 conversion (_conv.array_) are applied. */
6588 {
6591 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
6592 decay_conversion or an explicit cast. If it's a problematic cast,
6593 we'll complain about it below. */
6595 {
6600 {
6603 }
6604 }
6606 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6608 A template-argument for a non-type, non-template template-parameter
6609 shall be one of: [...]
6611 -- the name of a non-type template-parameter;
6612 -- the address of an object or function with external linkage, [...]
6613 expressed as "& id-expression" where the & is optional if the name
6614 refers to a function or array, or if the corresponding
6615 template-parameter is a reference.
6617 Here, we do not care about functions, as they are invalid anyway
6618 for a parameter of type pointer-to-object. */
6621 /* Non-type template parameters are OK. */
6622 ;
6626 {
6628 {
6631 "because %qD is a variable, not the address of "
6634 }
6636 {
6642 }
6643 /* Other values, like integer constants, might be valid
6644 non-type arguments of some other type. */
6646 }
6647 else
6648 {
6652 {
6657 }
6659 {
6665 }
6668 {
6673 }
6674 /* C++17: For a non-type template-parameter of reference or pointer
6675 type, the value of the constant expression shall not refer to (or
6676 for a pointer type, shall not be the address of):
6677 * a subobject (4.5),
6678 * a temporary object (15.2),
6679 * a string literal (5.13.5),
6680 * the result of a typeid expression (8.2.8), or
6681 * a predefined __func__ variable (11.4.1). */
6683 {
6686 decl);
6688 }
6692 {
6697 }
6699 {
6703 decl);
6705 }
6706 }
6713 }
6714 /* [temp.arg.nontype]/5, bullet 3
6716 For a non-type template-parameter of type reference to object, no
6717 conversions apply. The type referred to by the reference may be more
6718 cv-qualified than the (otherwise identical) type of the
6719 template-argument. The template-parameter is bound directly to the
6720 template-argument, which must be an lvalue. */
6722 {
6724 expr_type))
6728 {
6733 }
6736 {
6741 }
6743 /* [temp.arg.nontype]/1
6745 A template-argument for a non-type, non-template template-parameter
6746 shall be one of: [...]
6748 -- the address of an object or function with external linkage. */
6751 {
6754 {
6757 "because a reference variable does not have a constant "
6760 }
6761 }
6765 /* OK, dependent reference. We don't want to ask whether a DECL is
6767 else
6768 {
6770 {
6776 }
6778 /* DR 1155 allows internal linkage in C++11 and up. */
6781 {
6787 }
6790 }
6794 }
6795 /* [temp.arg.nontype]/5, bullet 4
6797 For a non-type template-parameter of type pointer to function, only
6798 the function-to-pointer conversion (_conv.func_) is applied. If the
6799 template-argument represents a set of overloaded functions (or a
6800 pointer to such), the matching function is selected from the set
6801 (_over.over_). */
6803 {
6804 /* If the argument is a template-id, we might not have enough
6805 context information to decay the pointer. */
6807 {
6811 }
6814 /* Null pointer values are OK in C++11. */
6820 }
6821 /* [temp.arg.nontype]/5, bullet 5
6823 For a non-type template-parameter of type reference to function, no
6824 conversions apply. If the template-argument represents a set of
6825 overloaded functions, the matching function is selected from the set
6826 (_over.over_). */
6828 {
6830 {
6832 {
6837 }
6839 }
6844 }
6845 /* [temp.arg.nontype]/5, bullet 6
6847 For a non-type template-parameter of type pointer to member function,
6848 no conversions apply. If the template-argument represents a set of
6849 overloaded member functions, the matching member function is selected
6850 from the set (_over.over_). */
6852 {
6857 /* [temp.arg.nontype] bullet 1 says the pointer to member
6858 expression must be a pointer-to-member constant. */
6863 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
6864 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
6867 }
6868 /* [temp.arg.nontype]/5, bullet 7
6870 For a non-type template-parameter of type pointer to data member,
6871 qualification conversions (_conv.qual_) are applied. */
6873 {
6874 /* [temp.arg.nontype] bullet 1 says the pointer to member
6875 expression must be a pointer-to-member constant. */
6883 }
6885 {
6887 {
6892 }
6894 }
6895 /* A template non-type parameter must be one of the above. */
6896 else
6899 /* Sanity check: did we actually convert the argument to the
6900 right type? */
6904 }
6906 /* Subroutine of coerce_template_template_parms, which returns 1 if
6907 PARM_PARM and ARG_PARM match using the rule for the template
6908 parameters of template template parameters. Both PARM and ARG are
6909 template parameters; the rest of the arguments are the same as for
6910 coerce_template_template_parms.
6911 */
6912 static int
6914 tree arg,
6915 tsubst_flags_t complain,
6916 tree in_decl,
6917 tree outer_args)
6918 {
6927 {
6929 /* We encounter instantiations of templates like
6930 template <template <template <class> class> class TT>
6931 class C; */
6932 {
6939 }
6940 /* Fall through. */
6945 /* Argument is a parameter pack but parameter is not. */
6950 /* The tsubst call is used to handle cases such as
6952 template <int> class C {};
6953 template <class T, template <T> class TT> class D {};
6954 D<int, C> d;
6956 i.e. the parameter list of TT depends on earlier parameters. */
6958 {
6963 }
6967 /* Argument is a parameter pack but parameter is not. */
6974 }
6977 }
6979 /* Coerce template argument list ARGLIST for use with template
6980 template-parameter TEMPL. */
6982 static tree
6984 tsubst_flags_t complain)
6985 {
6986 /* Consider an example where a template template parameter declared as
6988 template <class T, class U = std::allocator<T> > class TT
6990 The template parameter level of T and U are one level larger than
6991 of TT. To proper process the default argument of U, say when an
6992 instantiation `TT<int>' is seen, we need to build the full
6993 arguments containing {int} as the innermost level. Outer levels,
6994 available when not appearing as default template argument, can be
6995 obtained from the arguments of the enclosing template.
6997 Suppose that TT is later substituted with std::vector. The above
6998 instantiation is `TT<int, std::allocator<T> >' with TT at
6999 level 1, and T at level 2, while the template arguments at level 1
7000 becomes {std::vector} and the inner level 2 is {int}. */
7004 {
7006 /* We want arguments for the partial specialization, not arguments for
7007 the primary template. */
7009 else
7011 }
7013 {
7014 /* This is an argument of the current template, so we haven't set
7015 DECL_CONTEXT yet. */
7016 tree relevant_template_parms;
7018 /* Parameter levels that are greater than the level of the given
7019 template template parm are irrelevant. */
7026 }
7033 complain,
7036 }
7038 /* A cache of template template parameters with match-all default
7039 arguments. */
7041 static void
7043 {
7047 }
7048 static tree
7050 {
7055 }
7057 /* T is a bound template template-parameter. Copy its arguments into default
7058 arguments of the template template-parameter's template parameters. */
7060 static tree
7062 {
7085 {
7088 {
7091 }
7092 }
7096 }
7098 /* ARG is a bound potential template template-argument, and PARGS is a list
7099 of arguments for the corresponding template template-parameter. Adjust
7100 PARGS as appropriate for application to ARG's template, and if ARG is a
7101 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7102 arguments to the template template parameter. */
7104 static tree
7106 {
7110 {
7111 /* When comparing two template template-parameters in partial ordering,
7112 rewrite the one currently being used as an argument to have default
7113 arguments for all parameters. */
7119 }
7120 else
7121 {
7122 tree aparms
7127 }
7130 }
7132 /* Subroutine of unify for the case when PARM is a
7133 BOUND_TEMPLATE_TEMPLATE_PARM. */
7135 static int
7138 {
7142 /* The template template parm might be variadic and the argument
7143 not, so flatten both argument lists. */
7148 {
7149 /* In keeping with P0522R0, adjust P's template arguments
7150 to apply to A's template; then flatten it again. */
7159 /* If the P0522 adjustment eliminated a pack expansion, deduce
7160 empty packs. */
7166 }
7167 else
7168 {
7169 /* Deduce arguments T, i from TT<T> or TT<i>.
7170 We check each element of PARMVEC and ARGVEC individually
7171 rather than the whole TREE_VEC since they can have
7172 different number of elements, which is allowed under N2555. */
7176 /* Check if the parameters end in a pack, making them
7177 variadic. */
7184 /* If the template argument list of P contains a pack
7185 expansion that is not the last template argument, the
7186 entire template argument list is a non-deduced
7187 context. */
7205 DEDUCE_EXACT,
7208 }
7211 }
7213 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7214 template template parameters. Both PARM_PARMS and ARG_PARMS are
7215 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7216 or PARM_DECL.
7218 Consider the example:
7219 template <class T> class A;
7220 template<template <class U> class TT> class B;
7222 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7223 the parameters to A, and OUTER_ARGS contains A. */
7225 static int
7227 tree arg_parms,
7228 tsubst_flags_t complain,
7229 tree in_decl,
7230 tree outer_args)
7231 {
7243 {
7244 /* P0522R0: A template template-parameter P is at least as specialized as
7245 a template template-argument A if, given the following rewrite to two
7246 function templates, the function template corresponding to P is at
7247 least as specialized as the function template corresponding to A
7248 according to the partial ordering rules for function templates
7249 ([temp.func.order]). Given an invented class template X with the
7250 template parameter list of A (including default arguments):
7252 * Each of the two function templates has the same template parameters,
7253 respectively, as P or A.
7255 * Each function template has a single function parameter whose type is
7256 a specialization of X with template arguments corresponding to the
7257 template parameters from the respective function template where, for
7258 each template parameter PP in the template parameter list of the
7259 function template, a corresponding template argument AA is formed. If
7260 PP declares a parameter pack, then AA is the pack expansion
7261 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7263 If the rewrite produces an invalid type, then P is not at least as
7264 specialized as A. */
7266 /* So coerce P's args to apply to A's parms, and then deduce between A's
7267 args and the converted args. If that succeeds, A is at least as
7268 specialized as P, so they match.*/
7275 {
7281 }
7282 }
7284 /* Determine whether we have a parameter pack at the end of the
7285 template template parameter's template parameter list. */
7287 {
7294 {
7308 }
7309 }
7315 /* Check all of the template parameters except the parameter pack at
7316 the end (if any). */
7318 {
7327 outer_args))
7330 }
7333 {
7334 /* Check each of the template parameters in the template
7335 argument against the template parameter pack at the end of
7336 the template template parameter. */
7343 {
7350 outer_args))
7352 }
7353 }
7356 }
7358 /* Verifies that the deduced template arguments (in TARGS) for the
7359 template template parameters (in TPARMS) represent valid bindings,
7360 by comparing the template parameter list of each template argument
7361 to the template parameter list of its corresponding template
7362 template parameter, in accordance with DR150. This
7363 routine can only be called after all template arguments have been
7364 deduced. It will return TRUE if all of the template template
7365 parameter bindings are okay, FALSE otherwise. */
7366 bool
7368 {
7372 /* We're dealing with template parms in this process. */
7378 {
7383 {
7388 {
7389 /* Look inside the argument pack. */
7392 }
7395 {
7399 /* Extract the next argument from the argument
7400 pack. */
7404 /* Look at the pattern of the pack expansion. */
7407 /* Extract the template parameters from the template
7408 argument. */
7414 /* Verify that we can coerce the template template
7415 parameters from the template argument to the template
7416 parameter. This requires an exact match. */
7418 && !coerce_template_template_parms
7420 targ_parms,
7421 tf_none,
7422 tparm,
7423 targs))
7424 {
7427 }
7428 }
7429 }
7430 }
7432 out:
7436 }
7438 /* Since type attributes aren't mangled, we need to strip them from
7439 template type arguments. */
7441 static tree
7443 {
7453 }
7455 /* And from inside dependent non-type arguments like sizeof(Type). */
7457 static tree
7459 {
7469 }
7471 // A template declaration can be substituted for a constrained
7472 // template template parameter only when the argument is more
7473 // constrained than the parameter.
7474 static bool
7476 {
7479 /* For now, allow constrained template template arguments
7480 and unconstrained template template parameters. */
7486 // If the template parameter is constrained, we need to rewrite its
7487 // constraints in terms of the ARG's template parameters. This ensures
7488 // that all of the template parameter types will have the same depth.
7489 //
7490 // Note that this is only valid when coerce_template_template_parm is
7491 // true for the innermost template parameters of PARM and ARG. In other
7492 // words, because coercion is successful, this conversion will be valid.
7494 {
7501 }
7504 }
7506 // Convert a placeholder argument into a binding to the original
7507 // parameter. The original parameter is saved as the TREE_TYPE of
7508 // ARG.
7511 {
7514 }
7516 /* Convert the indicated template ARG as necessary to match the
7517 indicated template PARM. Returns the converted ARG, or
7518 error_mark_node if the conversion was unsuccessful. Error and
7519 warning messages are issued under control of COMPLAIN. This
7520 conversion is for the Ith parameter in the parameter list. ARGS is
7521 the full set of template arguments deduced so far. */
7523 static tree
7525 tree arg,
7526 tree args,
7527 tsubst_flags_t complain,
7529 tree in_decl)
7530 {
7531 tree orig_arg;
7532 tree val;
7538 /* Trivially convert placeholders. */
7547 {
7548 /* The template argument was the name of some
7549 member function. That's usually
7550 invalid, but static members are OK. In any
7551 case, grab the underlying fields/functions
7552 and issue an error later if required. */
7555 }
7563 /* When determining whether an argument pack expansion is a template,
7564 look at the pattern. */
7568 /* Deal with an injected-class-name used as a template template arg. */
7570 {
7573 {
7583 }
7584 }
7586 is_tmpl_type =
7602 {
7604 {
7608 }
7611 "to refer to a type member of a template parameter, "
7616 typename_type,
7617 complain);
7620 }
7622 {
7624 {
7626 {
7638 else
7641 }
7642 }
7644 }
7646 {
7648 {
7655 else
7658 }
7660 }
7663 /* We already did the appropriate conversion when packing args. */
7666 {
7668 {
7670 /* The number of argument required is not known yet.
7671 Just accept it for now. */
7673 else
7674 {
7676 tree argparm;
7678 /* Strip alias templates that are equivalent to another
7679 template. */
7685 args))
7686 {
7689 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7690 TEMPLATE_DECL. */
7692 {
7697 }
7698 }
7699 else
7700 {
7702 {
7709 }
7712 }
7714 // Check that the constraints are compatible before allowing the
7715 // substitution.
7718 {
7720 {
7726 }
7728 }
7729 }
7730 }
7731 else
7733 /* We only form one instance of each template specialization.
7734 Therefore, if we use a non-canonical variant (i.e., a
7735 typedef), any future messages referring to the type will use
7736 the typedef, which is confusing if those future uses do not
7737 themselves also use the typedef. */
7740 }
7741 else
7742 {
7746 {
7750 }
7751 else
7759 /* We used to call digest_init here. However, digest_init
7760 will report errors, which we don't want when complain
7761 is zero. More importantly, digest_init will try too
7762 hard to convert things: for example, `0' should not be
7763 converted to pointer type at this point according to
7764 the standard. Accepting this is not merely an
7765 extension, since deciding whether or not these
7766 conversions can occur is part of determining which
7767 function template to call, or whether a given explicit
7768 argument specification is valid. */
7770 else
7780 {
7781 /* Reject template arguments that are references to built-in
7782 functions with no library fallbacks. */
7791 }
7794 {
7795 /* Strip typedefs from the SCOPE_REF. */
7798 complain);
7801 }
7802 }
7805 }
7807 /* Coerces the remaining template arguments in INNER_ARGS (from
7808 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
7809 Returns the coerced argument pack. PARM_IDX is the position of this
7810 parameter in the template parameter list. ARGS is the original
7811 template argument list. */
7812 static tree
7815 tree args,
7816 tree inner_args,
7818 tree new_args,
7820 tree in_decl,
7821 tsubst_flags_t complain)
7822 {
7825 tree packed_args;
7826 tree argument_pack;
7833 {
7834 /* When the template parameter is a non-type template parameter pack
7835 or template template parameter pack whose type or template
7836 parameters use parameter packs, we know exactly how many arguments
7837 we are looking for. Build a vector of the instantiated decls for
7838 these template parameters in PACKED_PARMS. */
7839 /* We can't use make_pack_expansion here because it would interpret a
7840 _DECL as a use rather than a declaration. */
7854 /* If we're doing a partial instantiation of a member template,
7855 verify that all of the types used for the non-type
7856 template parameter pack are, in fact, valid for non-type
7857 template parameters. */
7860 {
7863 {
7867 }
7868 /* We don't know how many args we have yet, just
7869 use the unconverted ones for now. */
7871 }
7874 }
7875 /* Check if we have a placeholder pack, which indicates we're
7876 in the context of a introduction list. In that case we want
7877 to match this pack to the single placeholder. */
7881 {
7884 }
7885 else
7888 /* Convert the remaining arguments, which will be a part of the
7889 parameter pack "parm". */
7892 {
7898 {
7899 /* Once we've packed as many args as we have types, stop. */
7903 /* We don't know how many args we have yet, just
7904 use the unconverted ones for now. */
7906 else
7908 }
7911 {
7914 }
7915 else
7918 in_decl);
7922 }
7926 {
7931 }
7936 else
7937 {
7940 }
7947 }
7949 /* Returns the number of pack expansions in the template argument vector
7950 ARGS. */
7952 static int
7954 {
7959 {
7963 }
7965 }
7967 /* Convert all template arguments to their appropriate types, and
7968 return a vector containing the innermost resulting template
7969 arguments. If any error occurs, return error_mark_node. Error and
7970 warning messages are issued under control of COMPLAIN.
7972 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
7973 for arguments not specified in ARGS. Otherwise, if
7974 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
7975 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
7976 USE_DEFAULT_ARGS is false, then all arguments must be specified in
7977 ARGS. */
7979 static tree
7981 tree args,
7982 tree in_decl,
7983 tsubst_flags_t complain,
7986 {
7988 tree orig_inner_args;
7989 tree inner_args;
7990 tree new_args;
7991 tree new_inner_args;
7995 /* When used as a boolean value, indicates whether this is a
7996 variadic template parameter list. Since it's an int, we can also
7997 subtract it from nparms to get the number of non-variadic
7998 parameters. */
8003 /* Likewise for parameters with default arguments. */
8011 /* Determine if there are any parameter packs or default arguments. */
8013 {
8021 }
8024 /* If there are no parameters that follow a parameter pack, we need to
8025 expand any argument packs so that we can deduce a parameter pack from
8026 some non-packed args followed by an argument pack, as in variadic85.C.
8027 If there are such parameters, we need to leave argument packs intact
8028 so the arguments are assigned properly. This can happen when dealing
8029 with a nested class inside a partial specialization of a class
8030 template, as in variadic92.C, or when deducing a template parameter pack
8031 from a sub-declarator, as in variadic114.C. */
8035 /* Count any pack expansion args. */
8041 && require_all_args
8042 && !variadic_args_p
8043 && (!use_default_args
8046 {
8048 {
8050 {
8054 }
8055 else
8062 }
8065 }
8066 /* We can't pass a pack expansion to a non-pack parameter of an alias
8067 template (DR 1430). */
8071 && variadic_args_p
8073 {
8075 {
8077 {
8083 {
8086 "pack expansion argument for non-pack parameter "
8088 else
8090 "pack expansion argument for non-pack parameter "
8094 }
8095 }
8097 found:;
8098 }
8100 }
8102 /* We need to evaluate the template arguments, even though this
8103 template-id may be nested within a "sizeof". */
8112 {
8113 tree arg;
8114 tree parm;
8116 /* Get the Ith template parameter. */
8120 {
8123 }
8125 /* Calculate the next argument. */
8128 else
8133 {
8134 /* Some arguments will be placed in the
8135 template parameter pack PARM. */
8142 {
8143 /* We don't know how many args we have yet, just use the
8144 unconverted (and still packed) ones for now. */
8148 }
8152 /* Store this argument. */
8154 {
8155 lost++;
8156 /* We are done with all of the arguments. */
8158 }
8159 else
8160 {
8163 }
8166 }
8168 {
8170 {
8171 /* "If every valid specialization of a variadic template
8172 requires an empty template parameter pack, the template is
8173 ill-formed, no diagnostic required." So check that the
8174 pattern works with this parameter. */
8179 in_decl);
8181 {
8186 }
8188 /* Recover from missing typename. */
8192 /* We don't know how many args we have yet, just
8193 use the unconverted ones for now. */
8197 }
8198 }
8200 {
8201 /* There must be a default arg in this case. */
8204 /* The position of the first default template argument,
8205 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8206 Record that. */
8210 }
8211 else
8215 {
8218 }
8220 /* This only occurs if there was an error in the template
8221 parameter list itself (which we would already have
8222 reported) that we are trying to recover from, e.g., a class
8223 template with a parameter list such as
8224 template<typename..., typename>. */
8226 else
8232 lost++;
8234 }
8239 {
8241 {
8246 }
8248 }
8258 }
8260 /* Convert all template arguments to their appropriate types, and
8261 return a vector containing the innermost resulting template
8262 arguments. If any error occurs, return error_mark_node. Error and
8263 warning messages are not issued.
8265 Note that no function argument deduction is performed, and default
8266 arguments are used to fill in unspecified arguments. */
8267 tree
8269 {
8271 }
8273 /* Convert all template arguments to their appropriate type, and
8274 instantiate default arguments as needed. This returns a vector
8275 containing the innermost resulting template arguments, or
8276 error_mark_node if unsuccessful. */
8277 tree
8279 tsubst_flags_t complain)
8280 {
8282 }
8284 /* Like coerce_template_parms. If PARMS represents all template
8285 parameters levels, this function returns a vector of vectors
8286 representing all the resulting argument levels. Note that in this
8287 case, only the innermost arguments are coerced because the
8288 outermost ones are supposed to have been coerced already.
8290 Otherwise, if PARMS represents only (the innermost) vector of
8291 parameters, this function returns a vector containing just the
8292 innermost resulting arguments. */
8294 static tree
8296 tree args,
8297 tree in_decl,
8298 tsubst_flags_t complain,
8301 {
8304 tree coerced_args;
8307 {
8309 tree level;
8315 {
8316 tree l;
8320 require_all_args,
8321 use_default_args);
8322 else
8329 }
8330 }
8331 else
8334 require_all_args,
8335 use_default_args);
8337 }
8339 /* Returns 1 if template args OT and NT are equivalent. */
8341 int
8343 {
8352 /* For member templates */
8361 {
8378 }
8382 {
8385 /* Don't treat an alias template specialization with dependent
8386 arguments as equivalent to its underlying type when used as a
8387 template argument; we need them to be distinct so that we
8388 substitute into the specialization arguments at instantiation
8389 time. And aliases can't be equivalent without being ==, so
8390 we don't need to look any deeper.
8392 During partial ordering, however, we need to treat them normally so
8393 that we can order uses of the same alias with different
8394 cv-qualification (79960). */
8398 else
8400 }
8403 else
8404 {
8405 /* Try to treat a template non-type argument that has been converted
8406 to the parameter type as equivalent to one that hasn't yet. */
8419 }
8420 }
8422 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8423 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8424 NEWARG_PTR with the offending arguments if they are non-NULL. */
8426 int
8430 {
8443 {
8448 {
8454 }
8455 }
8457 }
8461 {
8463 }
8465 static void
8467 {
8477 /* We are called both from instantiate_decl, where we've already had a
8478 tinst_level pushed, and instantiate_template, where we haven't.
8479 Compensate. */
8490 else
8499 }
8502 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
8503 ARGLIST. Valid choices for FNS are given in the cp-tree.def
8504 documentation for TEMPLATE_ID_EXPR. */
8506 tree
8508 {
8509 tree type;
8517 {
8520 }
8523 {
8525 unknown_type_node,
8527 arglist);
8529 }
8536 }
8538 /* Within the scope of a template class S<T>, the name S gets bound
8539 (in build_self_reference) to a TYPE_DECL for the class, not a
8540 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
8541 or one of its enclosing classes, and that type is a template,
8542 return the associated TEMPLATE_DECL. Otherwise, the original
8543 DECL is returned.
8545 Also handle the case when DECL is a TREE_LIST of ambiguous
8546 injected-class-names from different bases. */
8548 tree
8550 {
8554 /* DR 176: A lookup that finds an injected-class-name (10.2
8555 [class.member.lookup]) can result in an ambiguity in certain cases
8556 (for example, if it is found in more than one base class). If all of
8557 the injected-class-names that are found refer to specializations of
8558 the same class template, and if the name is followed by a
8559 template-argument-list, the reference refers to the class template
8560 itself and not a specialization thereof, and is not ambiguous. */
8562 {
8565 {
8571 }
8574 else
8576 }
8582 }
8584 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
8585 parameters, find the desired type.
8587 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
8589 IN_DECL, if non-NULL, is the template declaration we are trying to
8590 instantiate.
8592 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
8593 the class we are looking up.
8595 Issue error and warning messages under control of COMPLAIN.
8597 If the template class is really a local class in a template
8598 function, then the FUNCTION_CONTEXT is the function in which it is
8599 being instantiated.
8601 ??? Note that this function is currently called *twice* for each
8602 template-id: the first time from the parser, while creating the
8603 incomplete type (finish_template_type), and the second type during the
8604 real instantiation (instantiate_template_class). This is surely something
8605 that we want to avoid. It also causes some problems with argument
8606 coercion (see convert_nontype_argument for more information on this). */
8608 static tree
8611 {
8613 tree t;
8616 spec_entry elt;
8617 hashval_t hash;
8620 {
8624 else
8625 {
8632 }
8635 }
8637 {
8640 /* If we are declaring a constructor, say A<T>::A<T>, we will get
8641 an implicit typename for the second A. Deal with it. */
8646 {
8649 }
8650 }
8653 {
8656 }
8658 {
8662 }
8664 {
8667 }
8669 /* Issue an error message if we didn't find a template. */
8671 {
8675 }
8678 /* Make sure it's a user visible template, if it was named by
8679 the user. */
8682 {
8684 {
8688 }
8690 }
8694 /* An alias that just changes the name of a template is equivalent to the
8695 other template, so if any of the arguments are pack expansions, strip
8696 the alias to avoid problems with a pack expansion passed to a non-pack
8697 alias template parameter (DR 1430). */
8702 {
8703 tree parm;
8712 }
8713 else
8714 {
8716 tree gen_tmpl;
8717 tree type_decl;
8725 /* An error occurred while building the template TEMPL, and a
8726 diagnostic has most certainly been emitted for that
8727 already. Let's propagate that error. */
8736 {
8737 /* We've been given an incomplete set of template arguments.
8738 For example, given:
8740 template <class T> struct S1 {
8741 template <class U> struct S2 {};
8742 template <class U> struct S2<U*> {};
8743 };
8745 we will be called with an ARGLIST of `U*', but the
8746 TEMPLATE will be `template <class T> template
8747 <class U> struct S1<T>::S2'. We must fill in the missing
8748 arguments. */
8752 }
8754 /* Now we should have enough arguments. */
8757 /* From here on, we're only interested in the most general
8758 template. */
8760 /* Calculate the BOUND_ARGS. These will be the args that are
8761 actually tsubst'd into the definition to create the
8762 instantiation. */
8764 complain,
8769 /* We were unable to bind the arguments. */
8772 /* In the scope of a template class, explicit references to the
8773 template class refer to the type of the template, not any
8774 instantiation of it. For example, in:
8776 template <class T> class C { void f(C<T>); }
8778 the `C<T>' is just the same as `C'. Outside of the
8779 class, however, such a reference is an instantiation. */
8783 {
8788 }
8790 /* If we already have this specialization, return it. */
8800 /* If the the template's constraints are not satisfied,
8801 then we cannot form a valid type.
8803 Note that the check is deferred until after the hash
8804 lookup. This prevents redundant checks on previously
8805 instantiated specializations. */
8807 {
8809 {
8812 }
8814 }
8818 /* If the deduced arguments are invalid, then the binding
8819 failed. */
8823 complain))
8830 {
8835 }
8845 /* Create the type. */
8847 {
8848 /* The user referred to a specialization of an alias
8849 template represented by GEN_TMPL.
8851 [temp.alias]/2 says:
8853 When a template-id refers to the specialization of an
8854 alias template, it is equivalent to the associated
8855 type obtained by substitution of its
8856 template-arguments for the template-parameters in the
8857 type-id of the alias template. */
8860 /* Note that the call above (by indirectly calling
8861 register_specialization in tsubst_decl) registers the
8862 TYPE_DECL representing the specialization of the alias
8863 template. So next time someone substitutes ARGLIST for
8864 the template parms into the alias template (GEN_TMPL),
8865 she'll get that TYPE_DECL back. */
8869 }
8871 {
8873 {
8884 }
8885 else
8886 {
8887 /* We don't want to call start_enum for this type, since
8888 the values for the enumeration constants may involve
8889 template parameters. And, no one should be interested
8890 in the enumeration constants for such a type. */
8893 }
8897 }
8899 {
8905 /* A local class. Make sure the decl gets registered properly. */
8910 /* This instantiation is another name for the primary
8911 template type. Set the TYPE_CANONICAL field
8912 appropriately. */
8915 /* Some of the template arguments require structural
8916 equality testing, so this template class requires
8917 structural equality testing. */
8919 }
8920 else
8923 /* If we called start_enum or pushtag above, this information
8924 will already be set up. */
8926 {
8933 }
8934 else
8938 {
8944 {
8947 }
8948 }
8952 {
8956 {
8957 tree attributes
8965 }
8966 }
8968 /* Let's consider the explicit specialization of a member
8969 of a class template specialization that is implicitly instantiated,
8970 e.g.:
8971 template<class T>
8972 struct S
8973 {
8974 template<class U> struct M {}; //#0
8975 };
8977 template<>
8978 template<>
8979 struct S<int>::M<char> //#1
8980 {
8981 int i;
8982 };
8983 [temp.expl.spec]/4 says this is valid.
8985 In this case, when we write:
8986 S<int>::M<char> m;
8988 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
8989 the one of #0.
8991 When we encounter #1, we want to store the partial instantiation
8992 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
8994 For all cases other than this "explicit specialization of member of a
8995 class template", we just want to store the most general template into
8996 the CLASSTYPE_TI_TEMPLATE of M.
8998 This case of "explicit specialization of member of a class template"
8999 only happens when:
9000 1/ the enclosing class is an instantiation of, and therefore not
9001 the same as, the context of the most general template, and
9002 2/ we aren't looking at the partial instantiation itself, i.e.
9003 the innermost arguments are not the same as the innermost parms of
9004 the most general template.
9006 So it's only when 1/ and 2/ happens that we want to use the partial
9007 instantiation of the member template in lieu of its most general
9008 template. */
9012 /* the enclosing class must be an instantiation... */
9015 {
9019 tree partial_inst_args =
9026 use_partial_inst_tmpl =
9027 /*...and we must not be looking at the partial instantiation
9028 itself. */
9030 partial_inst_args);
9031 }
9034 /* This case is easy; there are no member templates involved. */
9036 else
9037 {
9038 /* This is a full instantiation of a member template. Find
9039 the partial instantiation of which this is an instance. */
9041 /* Temporarily reduce by one the number of levels in the ARGLIST
9042 so as to avoid comparing the last set of arguments. */
9046 /* FOUND is either a proper class type, or an alias
9047 template specialization. In the later case, it's a
9048 TYPE_DECL, resulting from the substituting of arguments
9049 for parameters in the TYPE_DECL of the alias template
9050 done earlier. So be careful while getting the template
9051 of FOUND. */
9053 ? found
9057 }
9059 // Build template info for the new specialization.
9068 /* Note this use of the partial instantiation so we can check it
9069 later in maybe_process_partial_specialization. */
9076 /* Now that the type has been registered on the instantiations
9077 list, we set up the enumerators. Because the enumeration
9078 constants may involve the enumeration type itself, we make
9079 sure to register the type first, and then create the
9080 constants. That way, doing tsubst_expr for the enumeration
9081 constants won't result in recursive calls here; we'll find
9082 the instantiation and exit above. */
9086 /* If the type makes use of template parameters, the
9087 code that generates debugging information will crash. */
9090 /* Possibly limit visibility based on template args. */
9097 }
9098 }
9100 /* Wrapper for lookup_template_class_1. */
9102 tree
9105 {
9106 tree ret;
9112 }
9114 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
9116 tree
9118 {
9119 /* The type of the expression is NULL_TREE since the template-id could refer
9120 to an explicit or partial specialization. */
9123 /* Except that concepts are always bool. */
9126 }
9128 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9130 tree
9132 {
9136 /* We never want to return a VAR_DECL for a variable concept, since they
9137 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
9152 {
9154 {
9157 }
9159 }
9161 /* If a template-id refers to a specialization of a variable
9162 concept, then the expression is true if and only if the
9163 concept's constraints are satisfied by the given template
9164 arguments.
9166 NOTE: This is an extension of Concepts Lite TS that
9167 allows constraints to be used in expressions. */
9169 {
9172 }
9175 }
9177 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
9178 TARGS template args, and instantiate it if it's not dependent. */
9180 tree
9182 tsubst_flags_t complain)
9183 {
9186 {
9189 }
9192 }
9194 \f
9195 struct pair_fn_data
9196 {
9197 tree_fn_t fn;
9198 tree_fn_t any_fn;
9200 /* True when we should also visit template parameters that occur in
9201 non-deduced contexts. */
9204 };
9206 /* Called from for_each_template_parm via walk_tree. */
9208 static tree
9210 {
9217 #define WALK_SUBTREE(NODE) \
9218 do \
9219 { \
9220 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
9221 pfd->include_nondeduced_p, \
9222 pfd->any_fn); \
9223 if (result) goto out; \
9224 } \
9225 while (0)
9235 {
9239 /* Fall through. */
9245 else
9255 /* Since we're not going to walk subtrees, we have to do this
9256 explicitly here. */
9258 /* Fall through. */
9261 /* Check the return type. */
9264 /* Check the parameter types. Since default arguments are not
9265 instantiated until they are needed, the TYPE_ARG_TYPES may
9266 contain expressions that involve template parameters. But,
9267 no-one should be looking at them yet. And, once they're
9268 instantiated, they don't contain template parameters, so
9269 there's no point in looking at them then, either. */
9270 {
9271 tree parm;
9276 /* Since we've already handled the TYPE_ARG_TYPES, we don't
9277 want walk_tree walking into them itself. */
9279 }
9282 {
9286 }
9303 /* Fall through. */
9315 /* Record template parameters such as `T' inside `TT<T>'. */
9317 /* Fall through. */
9329 /* A template template parameter is encountered. */
9333 /* Already substituted template template parameter */
9338 /* A template-id in a TYPENAME_TYPE might be a deduced context after
9339 partial instantiation. */
9351 /* If there's no type, then this thing must be some expression
9352 involving template parameters. */
9374 }
9376 #undef WALK_SUBTREE
9378 /* We didn't find any template parameters we liked. */
9379 out:
9381 }
9383 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9384 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9385 call FN with the parameter and the DATA.
9386 If FN returns nonzero, the iteration is terminated, and
9387 for_each_template_parm returns 1. Otherwise, the iteration
9388 continues. If FN never returns a nonzero value, the value
9389 returned by for_each_template_parm is 0. If FN is NULL, it is
9390 considered to be the function which always returns 1.
9392 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9393 parameters that occur in non-deduced contexts. When false, only
9394 visits those template parameters that can be deduced. */
9396 static tree
9400 tree_fn_t any_fn)
9401 {
9403 tree result;
9405 /* Set up. */
9411 /* Walk the tree. (Conceptually, we would like to walk without
9412 duplicates, but for_each_template_parm_r recursively calls
9413 for_each_template_parm, so we would need to reorganize a fair
9414 bit to use walk_tree_without_duplicates, so we keep our own
9415 visited list.) */
9418 else
9421 for_each_template_parm_r,
9425 /* Clean up. */
9427 {
9430 }
9433 }
9435 /* Returns true if T depends on any template parameter. */
9437 int
9439 {
9469 else
9470 {
9473 }
9478 }
9480 /* Returns true iff current_function_decl is an incompletely instantiated
9481 template. Useful instead of processing_template_decl because the latter
9482 is set to 0 during instantiate_non_dependent_expr. */
9484 bool
9486 {
9495 }
9497 /* Returns true iff we are currently within a template other than a generic
9498 lambda. We test this by finding the outermost closure type and checking
9499 whether it is dependent. */
9501 bool
9503 {
9510 {
9513 else
9515 }
9519 else
9521 }
9523 /* Returns true if T depends on any template parameter with level LEVEL. */
9525 bool
9527 {
9530 }
9532 /* Returns true if the signature of DECL depends on any template parameter from
9533 its enclosing class. */
9535 bool
9537 {
9547 template_parm_outer_level,
9557 }
9559 /* Returns TRUE iff INST is an instantiation we don't need to do in an
9560 ill-formed translation unit, i.e. a variable or function that isn't
9561 usable in a constant expression. */
9565 {
9570 }
9572 /* Returns TRUE iff we should refuse to instantiate DECL because it's
9573 neglectable and instantiated from within an erroneous instantiation. */
9575 static bool
9577 {
9588 }
9596 /* We're starting to instantiate D; record the template instantiation context
9597 for diagnostics and to restore it later. */
9599 bool
9601 {
9603 }
9605 /* We're starting to instantiate D; record the template instantiation context
9606 at LOC for diagnostics and to restore it later. */
9608 bool
9610 {
9614 {
9615 /* Tell error.c not to try to instantiate any templates. */
9618 "template instantiation depth exceeds maximum of %d"
9620 max_tinst_depth);
9622 }
9624 /* If the current instantiation caused problems, don't let it instantiate
9625 anything else. Do allow deduction substitution and decls usable in
9626 constant expressions. */
9630 /* When not -quiet, dump template instantiations other than functions, since
9631 announce_function will take care of those. */
9650 }
9652 /* We're done instantiating this template; return to the instantiation
9653 context. */
9655 void
9657 {
9658 /* Restore the filename and line number stashed away when we started
9659 this instantiation. */
9663 }
9665 /* We're instantiating a deferred template; restore the template
9666 instantiation context in which the instantiation was requested, which
9667 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
9669 static tree
9671 {
9683 }
9685 /* Returns the TINST_LEVEL which gives the original instantiation
9686 context. */
9690 {
9696 }
9698 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
9699 vector of template arguments, as for tsubst.
9701 Returns an appropriate tsubst'd friend declaration. */
9703 static tree
9705 {
9706 tree new_friend;
9711 /* This was a friend declared with an explicit template
9712 argument list, e.g.:
9714 friend void f<>(T);
9716 to indicate that f was a template instantiation, not a new
9717 function declaration. Now, we have to figure out what
9718 instantiation of what template. */
9719 {
9721 tree new_args;
9722 tree tmpl;
9725 /* Friend functions are looked up in the containing namespace scope.
9726 We must enter that scope, to avoid finding member functions of the
9727 current class with same name. */
9742 tsk_none);
9744 }
9748 /* The NEW_FRIEND will look like an instantiation, to the
9749 compiler, but is not an instantiation from the point of view of
9750 the language. For example, we might have had:
9752 template <class T> struct S {
9753 template <class U> friend void f(T, U);
9754 };
9756 Then, in S<int>, template <class U> void f(int, U) is not an
9757 instantiation of anything. */
9763 {
9767 }
9769 /* The mangled name for the NEW_FRIEND is incorrect. The function
9770 is not a template instantiation and should not be mangled like
9771 one. Therefore, we forget the mangling here; we'll recompute it
9772 later if we need it. */
9774 {
9777 }
9780 {
9781 tree old_decl;
9782 tree new_friend_template_info;
9783 tree new_friend_result_template_info;
9784 tree ns;
9787 /* We must save some information from NEW_FRIEND before calling
9788 duplicate decls since that function will free NEW_FRIEND if
9789 possible. */
9791 new_friend_is_defn =
9796 {
9797 /* This declaration is a `primary' template. */
9800 new_friend_result_template_info
9802 }
9803 else
9806 /* Inside pushdecl_namespace_level, we will push into the
9807 current namespace. However, the friend function should go
9808 into the namespace of the template. */
9818 {
9819 /* This new friend declaration matched an existing
9820 declaration. For example, given:
9822 template <class T> void f(T);
9823 template <class U> class C {
9824 template <class T> friend void f(T) {}
9825 };
9827 the friend declaration actually provides the definition
9828 of `f', once C has been instantiated for some type. So,
9829 old_decl will be the out-of-class template declaration,
9830 while new_friend is the in-class definition.
9832 But, if `f' was called before this point, the
9833 instantiation of `f' will have DECL_TI_ARGS corresponding
9834 to `T' but not to `U', references to which might appear
9835 in the definition of `f'. Previously, the most general
9836 template for an instantiation of `f' was the out-of-class
9837 version; now it is the in-class version. Therefore, we
9838 run through all specialization of `f', adding to their
9839 DECL_TI_ARGS appropriately. In particular, they need a
9840 new set of outer arguments, corresponding to the
9841 arguments for this class instantiation.
9843 The same situation can arise with something like this:
9845 friend void f(int);
9846 template <class T> class C {
9847 friend void f(T) {}
9848 };
9850 when `C<int>' is instantiated. Now, `f(int)' is defined
9851 in the class. */
9854 /* On the other hand, if the in-class declaration does
9855 *not* provide a definition, then we don't want to alter
9856 existing definitions. We can just leave everything
9857 alone. */
9858 ;
9859 else
9860 {
9864 /* Overwrite whatever template info was there before, if
9865 any, with the new template information pertaining to
9866 the declaration. */
9870 {
9871 /* We should have called reregister_specialization in
9872 duplicate_decls. */
9877 /* Instantiate it if the global has already been used. */
9881 }
9882 else
9883 {
9884 tree t;
9886 /* Indicate that the old function template is a partial
9887 instantiation. */
9895 /* Reassign any specializations already in the hash table
9896 to the new more general template, and add the
9897 additional template args. */
9901 {
9903 spec_entry elt;
9915 register_specialization
9918 }
9920 }
9921 }
9923 /* The information from NEW_FRIEND has been merged into OLD_DECL
9924 by duplicate_decls. */
9926 }
9927 }
9928 else
9929 {
9933 /* In the code
9934 template <class T> class C {
9935 template <class U> friend void C1<U>::f (); // case 1
9936 friend void C2<T>::f (); // case 2
9937 };
9938 we only need to make sure CONTEXT is a complete type for
9939 case 2. To distinguish between the two cases, we note that
9940 CONTEXT of case 1 remains dependent type after tsubst while
9941 this isn't true for case 2. */
9951 {
9953 /* do_friend adds the TEMPLATE_DECL for any member friend
9954 template even if it isn't a member template, i.e.
9955 template <class T> friend A<T>::f();
9956 Look through it in that case. */
9960 /* Check to see that the declaration is really present, and,
9961 possibly obtain an improved declaration. */
9966 }
9967 }
9970 }
9972 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
9973 template arguments, as for tsubst.
9975 Returns an appropriate tsubst'd friend type or error_mark_node on
9976 failure. */
9978 static tree
9980 {
9981 tree friend_type;
9982 tree tmpl;
9983 tree context;
9986 {
9989 }
9994 {
9997 else
9999 }
10001 /* Look for a class template declaration. We look for hidden names
10002 because two friend declarations of the same template are the
10003 same. For example, in:
10005 struct A {
10006 template <typename> friend class F;
10007 };
10008 template <typename> struct B {
10009 template <typename> friend class F;
10010 };
10012 both F templates are the same. */
10016 /* But, if we don't find one, it might be because we're in a
10017 situation like this:
10019 template <class T>
10020 struct S {
10021 template <class U>
10022 friend struct S;
10023 };
10025 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
10026 for `S<int>', not the TEMPLATE_DECL. */
10028 {
10031 }
10034 {
10035 /* The friend template has already been declared. Just
10036 check to see that the declarations match, and install any new
10037 default parameters. We must tsubst the default parameters,
10038 of course. We only need the innermost template parameters
10039 because that is all that redeclare_class_template will look
10040 at. */
10043 {
10044 tree parms;
10045 location_t saved_input_location;
10055 }
10058 }
10059 else
10060 {
10061 /* The friend template has not already been declared. In this
10062 case, the instantiation of the template class will cause the
10063 injection of this template into the global scope. */
10068 /* The new TMPL is not an instantiation of anything, so we
10069 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
10070 the new type because that is supposed to be the corresponding
10071 template decl, i.e., TMPL. */
10078 /* Inject this template into the global scope. */
10080 }
10083 {
10086 else
10088 }
10091 }
10093 /* Returns zero if TYPE cannot be completed later due to circularity.
10094 Otherwise returns one. */
10096 static int
10098 {
10108 else
10110 }
10115 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
10116 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
10118 static tree
10121 {
10130 {
10137 clauses
10141 else
10143 }
10144 /* If the first attribute argument is an identifier, don't
10145 pass it through tsubst. Attributes like mode, format,
10146 cleanup and several target specific attributes expect it
10147 unmodified. */
10149 {
10150 tree chain
10155 }
10157 {
10158 /* An attribute pack expansion. */
10167 {
10171 }
10173 }
10174 else
10181 }
10183 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
10184 unchanged or a new TREE_LIST chain. */
10186 static tree
10189 {
10194 {
10198 }
10202 {
10205 {
10208 {
10210 do
10215 }
10216 }
10218 }
10221 }
10223 /* Apply any attributes which had to be deferred until instantiation
10224 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
10225 ARGS, COMPLAIN, IN_DECL are as tsubst. */
10227 static void
10230 {
10232 tree t;
10239 {
10243 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
10244 to our attributes parameter. */
10246 }
10247 else
10248 {
10250 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
10251 lookup_template_class_1, and should be preserved. */
10255 }
10259 {
10263 }
10267 {
10272 {
10275 {
10279 do
10282 }
10283 else
10285 }
10288 }
10289 }
10291 /* Perform (or defer) access check for typedefs that were referenced
10292 from within the template TMPL code.
10293 This is a subroutine of instantiate_decl and instantiate_class_template.
10294 TMPL is the template to consider and TARGS is the list of arguments of
10295 that template. */
10297 static void
10299 {
10300 location_t saved_location;
10311 {
10323 /* Make access check error messages point to the location
10324 of the use of the typedef. */
10328 tf_warning_or_error);
10329 }
10331 }
10333 static tree
10335 {
10337 tree typedecl;
10338 tree pbinfo;
10339 tree base_list;
10341 tree fn_context;
10350 /* Figure out which template is being instantiated. */
10354 /* Determine what specialization of the original template to
10355 instantiate. */
10358 {
10361 }
10363 {
10364 /* This TYPE is actually an instantiation of a partial
10365 specialization. We replace the innermost set of ARGS with
10366 the arguments appropriate for substitution. For example,
10367 given:
10369 template <class T> struct S {};
10370 template <class T> struct S<T*> {};
10372 and supposing that we are instantiating S<int*>, ARGS will
10373 presently be {int*} -- but we need {int}. */
10376 }
10377 else
10378 {
10381 }
10383 /* If the template we're instantiating is incomplete, then clearly
10384 there's nothing we can do. */
10388 /* If we've recursively instantiated too many templates, stop. */
10392 /* Now we're really doing the instantiation. Mark the type as in
10393 the process of being defined. */
10396 /* We may be in the middle of deferred access check. Disable
10397 it now. */
10404 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10409 else
10410 {
10413 }
10414 /* Use #pragma pack from the template context. */
10420 /* Set the input location to the most specialized template definition.
10421 This is needed if tsubsting causes an error. */
10433 {
10436 /* Adjust visibility for template arguments. */
10438 }
10444 /* We should never instantiate a nested class before its enclosing
10445 class; we need to look up the nested class by name before we can
10446 instantiate it, and that lookup should instantiate the enclosing
10447 class. */
10453 {
10454 tree pbase_binfo;
10455 tree pushed_scope;
10458 /* We must enter the scope containing the type, as that is where
10459 the accessibility of types named in dependent bases are
10460 looked up from. */
10463 /* Substitute into each of the bases to determine the actual
10464 basetypes. */
10466 {
10467 tree base;
10473 {
10474 expanded_bases =
10481 }
10484 {
10486 /* Extract the already-expanded base class. */
10488 else
10489 /* Substitute to figure out the base class. */
10491 NULL_TREE);
10499 }
10500 }
10502 /* The list is now in reverse order; correct that. */
10507 }
10508 /* Now call xref_basetypes to set up all the base-class
10509 information. */
10517 /* Now that our base classes are set up, enter the scope of the
10518 class, so that name lookups into base classes, etc. will work
10519 correctly. This is precisely analogous to what we do in
10520 begin_class_definition when defining an ordinary non-template
10521 class, except we also need to push the enclosing classes. */
10524 /* Now members are processed in the order of declaration. */
10527 {
10531 {
10533 {
10534 /* Build new CLASSTYPE_NESTED_UTDS. */
10536 tree newtag;
10542 /* If the member is a class template, then -- even after
10543 substitution -- there may be dependent types in the
10544 template argument list for the class. We increment
10545 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
10546 that function will assume that no types are dependent
10547 when outside of a template. */
10557 {
10561 /* Unfortunately, lookup_template_class sets
10562 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
10563 instantiation (i.e., for the type of a member
10564 template class nested within a template class.)
10565 This behavior is required for
10566 maybe_process_partial_specialization to work
10567 correctly, but is not accurate in this case;
10568 the TAG is not an instantiation of anything.
10569 (The corresponding TEMPLATE_DECL is an
10570 instantiation, but the TYPE is not.) */
10573 /* Now, we call pushtag to put this NEWTAG into the scope of
10574 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
10575 pushtag calling push_template_decl. We don't have to do
10576 this for enums because it will already have been done in
10577 tsubst_enum. */
10581 }
10582 }
10584 {
10585 tree r;
10594 /* Instantiate members marked with attribute used. */
10600 }
10603 /* A closure type for a lambda in a default argument for a
10604 member template. Ignore it; it will be instantiated with
10606 else
10607 {
10608 /* Build new TYPE_FIELDS. */
10610 {
10611 tree condition;
10614 condition =
10624 }
10626 {
10627 tree r;
10631 /* The file and line for this declaration, to
10632 assist in error message reporting. Since we
10633 called push_tinst_level above, we don't need to
10634 restore these. */
10644 {
10645 /* A capture pack became multiple fields. */
10648 }
10651 {
10655 {
10656 /* In [temp.inst]:
10658 [t]he initialization (and any associated
10659 side-effects) of a static data member does
10660 not occur unless the static data member is
10661 itself used in a way that requires the
10662 definition of the static data member to
10663 exist.
10665 Therefore, we do not substitute into the
10666 initialized for the static data member here. */
10667 finish_static_data_member_decl
10673 /* Instantiate members marked with attribute used. */
10676 }
10678 {
10679 /* Determine whether R has a valid type and can be
10680 completed later. If R is invalid, then its type
10681 is replaced by error_mark_node. */
10687 {
10688 /* If R's type couldn't be completed and
10689 it isn't a flexible array member (whose
10690 type is incomplete by definition) give
10691 an error. */
10694 }
10695 }
10697 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10698 such a thing will already have been added to the field
10699 list by tsubst_enum in finish_member_declaration in the
10700 CLASSTYPE_NESTED_UTDS case above. */
10704 {
10707 }
10708 }
10709 }
10710 }
10711 }
10712 else
10713 {
10716 {
10717 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10723 {
10724 /* template <class T> friend class C; */
10727 }
10729 {
10730 /* template <class T> friend class C::D; */
10736 }
10739 {
10740 /* This could be either
10742 friend class T::C;
10744 when dependent_type_p is false or
10746 template <class U> friend class T::C;
10748 otherwise. */
10749 /* Bump processing_template_decl in case this is something like
10750 template <class T> friend struct A<T>::B. */
10757 }
10761 {
10762 /* friend class C;
10764 where C hasn't been declared yet. Let's lookup name
10765 from namespace scope directly, bypassing any name that
10766 come from dependent base class. */
10769 /* The call to xref_tag_from_type does injection for friend
10770 classes. */
10772 friend_type =
10776 }
10778 /* friend class C<T>; */
10781 /* Otherwise it's
10783 friend class C;
10785 where C is already declared or
10787 friend class C<int>;
10789 We don't have to do anything in these cases. */
10792 /* Trick make_friend_class into realizing that the friend
10793 we're adding is a template, not an ordinary class. It's
10794 important that we use make_friend_class since it will
10795 perform some error-checking and output cross-reference
10796 information. */
10804 }
10805 else
10806 {
10807 /* Build new DECL_FRIENDLIST. */
10808 tree r;
10810 /* The file and line for this declaration, to
10811 assist in error message reporting. Since we
10812 called push_tinst_level above, we don't need to
10813 restore these. */
10817 {
10820 }
10825 {
10828 }
10829 }
10830 }
10831 }
10834 {
10835 /* Restore these before substituting into the lambda capture
10836 initializers. */
10839 }
10842 {
10845 {
10851 {
10852 /* Set function_depth to avoid garbage collection. */
10856 }
10858 /* We need to instantiate the capture list from the template
10859 after we've instantiated the closure members, but before we
10860 consider adding the conversion op. Also keep any captures
10861 that may have been added during instantiation of the op(). */
10863 tree tmpl_cap
10872 }
10873 else
10875 }
10877 /* Set the file and line number information to whatever is given for
10878 the class itself. This puts error messages involving generated
10879 implicit functions at a predictable point, and the same point
10880 that would be used for non-template classes. */
10887 /* We don't instantiate default arguments for member functions. 14.7.1:
10889 The implicit instantiation of a class template specialization causes
10890 the implicit instantiation of the declarations, but not of the
10891 definitions or default arguments, of the class member functions,
10892 member classes, static data members and member templates.... */
10894 /* Some typedefs referenced from within the template code need to be access
10895 checked at template instantiation time, i.e now. These types were
10896 added to the template at parsing time. Let's get those and perform
10897 the access checks then. */
10907 /* The vtable for a template class can be emitted in any translation
10908 unit in which the class is instantiated. When there is no key
10909 method, however, finish_struct_1 will already have added TYPE to
10910 the keyed_classes. */
10915 }
10917 /* Wrapper for instantiate_class_template_1. */
10919 tree
10921 {
10922 tree ret;
10927 }
10929 static tree
10931 {
10932 tree r;
10938 else
10939 {
10946 }
10948 }
10950 /* Given a function parameter pack TMPL_PARM and some function parameters
10951 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
10952 and set *SPEC_P to point at the next point in the list. */
10954 tree
10956 {
10957 /* Collect all of the extra "packed" parameters into an
10958 argument pack. */
10959 tree parmvec;
10969 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
10975 /* Build the argument packs. */
10980 }
10982 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
10983 NONTYPE_ARGUMENT_PACK. */
10985 static tree
10987 {
10989 }
10991 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
10992 pack expansion with no extra args, 2 if it has extra args, or 0
10993 if it is not a pack expansion. */
10995 static int
10997 {
11003 /* A decl pack is itself an expansion. */
11010 }
11013 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
11015 static tree
11017 {
11024 }
11026 /* This is a subroutine of tsubst_pack_expansion.
11028 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
11029 mechanism to store the (non complete list of) arguments of the
11030 substitution and return a non substituted pack expansion, in order
11031 to wait for when we have enough arguments to really perform the
11032 substitution. */
11034 static bool
11038 {
11039 /* If one pack has an expansion and another pack has a normal
11040 argument or if one pack has an empty argument and an another
11041 one hasn't then tsubst_pack_expansion cannot perform the
11042 substitution and need to fall back on the
11043 PACK_EXPANSION_EXTRA mechanism. */
11051 {
11054 parm_pack;
11056 {
11061 /* We can't substitute a pack expansion with extra args into
11062 our pattern. */
11066 else
11068 }
11072 }
11074 }
11076 /* [temp.variadic]/6 says that:
11078 The instantiation of a pack expansion [...]
11079 produces a list E1,E2, ..., En, where N is the number of elements
11080 in the pack expansion parameters.
11082 This subroutine of tsubst_pack_expansion produces one of these Ei.
11084 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
11085 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
11086 PATTERN, and each TREE_VALUE is its corresponding argument pack.
11087 INDEX is the index 'i' of the element Ei to produce. ARGS,
11088 COMPLAIN, and IN_DECL are the same parameters as for the
11089 tsubst_pack_expansion function.
11091 The function returns the resulting Ei upon successful completion,
11092 or error_mark_node.
11094 Note that this function possibly modifies the ARGS parameter, so
11095 it's the responsibility of the caller to restore it. */
11097 static tree
11099 tree parm_packs,
11101 tree args /* This parm gets
11103 tsubst_flags_t complain,
11104 tree in_decl)
11105 {
11106 tree t;
11109 /* For each parameter pack, change the substitution of the parameter
11110 pack to the ith argument in its argument pack, then expand the
11111 pattern. */
11113 {
11118 ith_elem_is_expansion |=
11121 /* Select the Ith argument from the pack. */
11124 {
11126 {
11131 }
11132 else
11134 }
11135 else
11136 {
11141 {
11143 /* Update the corresponding argument. */
11145 }
11146 else
11147 /* Re-use the ARGUMENT_PACK_SELECT. */
11149 }
11151 }
11153 /* Substitute into the PATTERN with the (possibly altered)
11154 arguments. */
11156 /* Expanding a fixed parameter pack from
11157 coerce_template_parameter_pack. */
11162 {
11165 else
11168 }
11172 else
11175 /* If the Ith argument pack element is a pack expansion, then
11176 the Ith element resulting from the substituting is going to
11177 be a pack expansion as well. */
11182 }
11184 /* When the unexpanded parameter pack in a fold expression expands to an empty
11185 sequence, the value of the expression is as follows; the program is
11186 ill-formed if the operator is not listed in this table.
11188 && true
11189 || false
11190 , void() */
11192 tree
11194 {
11198 {
11207 }
11213 }
11215 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11216 form an expression that combines the two terms using the
11217 operator of T. */
11219 static tree
11221 {
11225 // Handle compound assignment operators.
11230 {
11240 complain);
11241 }
11242 }
11244 /* Substitute ARGS into the pack of a fold expression T. */
11248 {
11250 }
11252 /* Substitute ARGS into the pack of a fold expression T. */
11256 {
11258 }
11260 /* Expand a PACK of arguments into a grouped as left fold.
11261 Given a pack containing elements A0, A1, ..., An and an
11262 operator @, this builds the expression:
11264 ((A0 @ A1) @ A2) ... @ An
11266 Note that PACK must not be empty.
11268 The operator is defined by the original fold expression T. */
11270 static tree
11272 {
11275 {
11278 }
11280 }
11282 /* Substitute into a unary left fold expression. */
11284 static tree
11286 tree in_decl)
11287 {
11292 {
11296 }
11299 else
11301 }
11303 /* Substitute into a binary left fold expression.
11305 Do ths by building a single (non-empty) vector of argumnts and
11306 building the expression from those elements. */
11308 static tree
11310 tree in_decl)
11311 {
11320 {
11325 }
11333 }
11335 /* Expand a PACK of arguments into a grouped as right fold.
11336 Given a pack containing elementns A0, A1, ..., and an
11337 operator @, this builds the expression:
11339 A0@ ... (An-2 @ (An-1 @ An))
11341 Note that PACK must not be empty.
11343 The operator is defined by the original fold expression T. */
11345 tree
11347 {
11348 // Build the expression.
11352 {
11355 }
11357 }
11359 /* Substitute into a unary right fold expression. */
11361 static tree
11363 tree in_decl)
11364 {
11369 {
11373 }
11376 else
11378 }
11380 /* Substitute into a binary right fold expression.
11382 Do ths by building a single (non-empty) vector of arguments and
11383 building the expression from those elements. */
11385 static tree
11387 tree in_decl)
11388 {
11397 {
11402 }
11411 }
11414 /* Substitute ARGS into T, which is an pack expansion
11415 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
11416 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
11417 (if only a partial substitution could be performed) or
11418 ERROR_MARK_NODE if there was an error. */
11419 tree
11421 tree in_decl)
11422 {
11423 tree pattern;
11427 tree result;
11435 /* Add in any args remembered from an earlier partial instantiation. */
11440 /* Determine the argument packs that will instantiate the parameter
11441 packs used in the expansion expression. While we're at it,
11442 compute the number of arguments to be expanded and make sure it
11443 is consistent. */
11446 {
11453 {
11458 else
11461 }
11463 {
11464 /* ??? Support use in other patterns. */
11468 }
11470 {
11471 /* We know we have correct local_specializations if this
11472 expansion is at function scope, or if we're dealing with a
11473 local parameter in a requires expression; for the latter,
11474 tsubst_requires_expr set it up appropriately. */
11477 else
11478 /* We can't rely on local_specializations for a parameter
11479 name used later in a function declaration (such as in a
11480 late-specified return type). Even if it exists, it might
11481 have the wrong value for a recursive call. */
11485 {
11486 /* This parameter pack was used in an unevaluated context. Just
11487 make a dummy decl, since it's only used for its type. */
11490 /* Partial instantiation of the parm_pack, we can't build
11491 up an argument pack yet. */
11493 else
11495 }
11496 }
11499 else
11500 {
11506 }
11513 /* This can only happen if we forget to expand an argument
11514 pack somewhere else. Just return an error, silently. */
11515 {
11519 }
11522 {
11526 /* Don't bother trying to do a partial substitution with
11527 incomplete packs; we'll try again after deduction. */
11534 {
11539 pattern);
11540 else
11542 pattern);
11544 }
11546 /* Keep track of the parameter packs and their corresponding
11547 argument packs. */
11550 }
11551 else
11552 {
11553 /* We can't substitute for this parameter pack. We use a flag as
11554 well as the missing_level counter because function parameter
11555 packs don't have a level. */
11558 }
11559 }
11561 /* If the expansion is just T..., return the matching argument pack, unless
11562 we need to call convert_from_reference on all the elements. This is an
11563 important optimization; see c++/68422. */
11566 {
11568 /* Types need no adjustment, nor does sizeof..., and if we still have
11569 some pack expansion args we won't do anything yet. */
11574 /* Also optimize expression pack expansions if we can tell that the
11575 elements won't have reference type. */
11581 /* Otherwise use the normal path so we get convert_from_reference. */
11582 }
11584 /* We cannot expand this expansion expression, because we don't have
11585 all of the argument packs we need. */
11587 {
11588 /* We got some full packs, but we can't substitute them in until we
11589 have values for all the packs. So remember these until then. */
11594 }
11596 {
11597 /* There were no real arguments, we're just replacing a parameter
11598 pack with another version of itself. Substitute into the
11599 pattern and return a PACK_EXPANSION_*. The caller will need to
11600 deal with that. */
11604 else
11608 }
11613 {
11614 /* We're in a late-specified return type, so create our own local
11615 specializations map; the current map is either NULL or (in the
11616 case of recursive unification) might have bindings that we don't
11617 want to use or alter. */
11620 }
11622 /* For each argument in each argument pack, substitute into the
11623 pattern. */
11627 {
11629 i,
11631 in_decl);
11634 {
11637 }
11638 }
11640 /* Update ARGS to restore the substitution from parameter packs to
11641 their argument packs. */
11643 {
11649 else
11650 {
11658 /* Update the corresponding argument. */
11662 else
11664 }
11665 }
11668 {
11671 }
11673 /* If the dependent pack arguments were such that we end up with only a
11674 single pack expansion again, there's no need to keep it in a TREE_VEC. */
11680 }
11682 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
11683 TMPL. We do this using DECL_PARM_INDEX, which should work even with
11684 parameter packs; all parms generated from a function parameter pack will
11685 have the same DECL_PARM_INDEX. */
11687 tree
11689 {
11691 tree patparm;
11694 {
11700 }
11701 else
11702 {
11707 }
11710 }
11712 /* Make an argument pack out of the TREE_VEC VEC. */
11714 static tree
11716 {
11717 tree pack;
11721 else
11722 {
11725 }
11728 }
11730 /* Return an exact copy of template args T that can be modified
11731 independently. */
11733 static tree
11735 {
11743 {
11748 }
11754 }
11756 /* Substitute ARGS into the vector or list of template arguments T. */
11758 static tree
11760 {
11772 {
11774 tree new_arg;
11779 {
11780 /* Substitute into an expansion expression. */
11784 /* Add to the expanded length adjustment the number of
11785 expanded arguments. We subtract one from this
11786 measurement, because the argument pack expression
11787 itself is already counted as 1 in
11788 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
11789 the argument pack is empty. */
11791 }
11793 {
11794 /* Substitute into each of the arguments. */
11803 else
11808 }
11809 else
11818 }
11823 /* Make space for the expanded arguments coming from template
11824 argument packs. */
11826 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
11827 arguments for a member template.
11828 In that case each TREE_VEC in ORIG_T represents a level of template
11829 arguments, and ORIG_T won't carry any non defaulted argument count.
11830 It will rather be the nested TREE_VECs that will carry one.
11831 In other words, ORIG_T carries a non defaulted argument count only
11832 if it doesn't contain any nested TREE_VEC. */
11834 {
11838 }
11840 {
11844 {
11847 /* Now expand the template argument pack "in place". */
11850 }
11851 else
11852 {
11854 out++;
11855 }
11856 }
11859 }
11861 /* Substitute ARGS into one level PARMS of template parameters. */
11863 static tree
11865 {
11872 {
11880 }
11883 }
11885 /* Return the result of substituting ARGS into the template parameters
11886 given by PARMS. If there are m levels of ARGS and m + n levels of
11887 PARMS, then the result will contain n levels of PARMS. For
11888 example, if PARMS is `template <class T> template <class U>
11889 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
11890 result will be `template <int*, double, class V>'. */
11892 static tree
11894 {
11898 /* When substituting into a template, we must set
11899 PROCESSING_TEMPLATE_DECL as the template parameters may be
11900 dependent if they are based on one-another, and the dependency
11901 predicates are short-circuit outside of templates. */
11908 {
11915 }
11920 }
11922 /* Return the result of substituting ARGS into one template parameter
11923 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
11924 parameter and which TREE_PURPOSE is the default argument of the
11925 template parameter. */
11927 static tree
11929 {
11950 }
11952 /* Substitute the ARGS into the indicated aggregate (or enumeration)
11953 type T. If T is not an aggregate or enumeration type, it is
11954 handled as if by tsubst. IN_DECL is as for tsubst. If
11955 ENTERING_SCOPE is nonzero, T is the context for a template which
11956 we are presently tsubst'ing. Return the substituted value. */
11958 static tree
11960 tree args,
11961 tsubst_flags_t complain,
11962 tree in_decl,
11964 {
11969 {
11974 /* Fall through. */
11978 {
11979 tree argvec;
11980 tree context;
11981 tree r;
11985 /* In "sizeof(X<I>)" we need to evaluate "I". */
11991 /* First, determine the context for the type we are looking
11992 up. */
11995 {
11998 /* If context is a nested class inside a class template,
11999 it may still need to be instantiated (c++/33959). */
12001 }
12003 /* Then, figure out what arguments are appropriate for the
12004 type we are trying to find. For example, given:
12006 template <class T> struct S;
12007 template <class T, class U> void f(T, U) { S<U> su; }
12009 and supposing that we are instantiating f<int, double>,
12010 then our ARGS will be {int, double}, but, when looking up
12011 S we only want {double}. */
12016 else
12017 {
12021 }
12027 }
12028 else
12029 /* This is not a template type, so there's nothing to do. */
12034 }
12035 }
12039 /* Substitute into the default argument ARG (a default argument for
12040 FN), which has the indicated TYPE. */
12042 tree
12044 tsubst_flags_t complain)
12045 {
12050 /* This can happen in invalid code. */
12065 /* This default argument came from a template. Instantiate the
12066 default argument here, not in tsubst. In the case of
12067 something like:
12069 template <class T>
12070 struct S {
12071 static T t();
12072 void f(T = t());
12073 };
12075 we must be careful to do name lookup in the scope of S<T>,
12076 rather than in the current class. */
12078 /* The "this" pointer is not valid in a default argument. */
12080 {
12085 }
12090 /* The default argument expression may cause implicitly defined
12091 member functions to be synthesized, which will result in garbage
12092 collection. We must treat this situation as if we were within
12093 the body of function so as to avoid collecting live data on the
12094 stack. */
12104 /* Restore the "this" pointer. */
12106 {
12109 }
12116 /* Make sure the default argument is reasonable. */
12122 {
12126 }
12129 }
12131 /* Substitute into all the default arguments for FN. */
12133 static void
12135 {
12136 tree arg;
12137 tree tmpl_args;
12141 /* If this function is not yet instantiated, we certainly don't need
12142 its default arguments. */
12145 /* Don't do this again for clones. */
12151 arg;
12157 complain);
12158 }
12160 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
12162 static tree
12164 tree lambda_fntype)
12165 {
12170 /* Nobody should be tsubst'ing into non-template functions. */
12174 {
12175 /* If T is not dependent, just return it. */
12179 /* Calculate the most general template of which R is a
12180 specialization, and the complete set of arguments used to
12181 specialize R. */
12184 (DECL_TEMPLATE_RESULT
12190 /* Check to see if we already have this specialization. */
12192 {
12196 }
12198 /* We can see more levels of arguments than parameters if
12199 there was a specialization of a member template, like
12200 this:
12202 template <class T> struct S { template <class U> void f(); }
12203 template <> template <class U> void S<int>::f(U);
12205 Here, we'll be substituting into the specialization,
12206 because that's where we can find the code we actually
12207 want to generate, but we'll have enough arguments for
12208 the most general template.
12210 We also deal with the peculiar case:
12212 template <class T> struct S {
12213 template <class U> friend void f();
12214 };
12215 template <class U> void f() {}
12216 template S<int>;
12217 template void f<double>();
12219 Here, the ARGS for the instantiation of will be {int,
12220 double}. But, we only need as many ARGS as there are
12221 levels of template parameters in CODE_PATTERN. We are
12222 careful not to get fooled into reducing the ARGS in
12223 situations like:
12225 template <class T> struct S { template <class U> void f(U); }
12226 template <class T> template <> void S<T>::f(int) {}
12228 which we can spot because the pattern will be a
12229 specialization in this case. */
12236 }
12237 else
12238 {
12239 /* This special case arises when we have something like this:
12241 template <class T> struct S {
12242 friend void f<int>(int, double);
12243 };
12245 Here, the DECL_TI_TEMPLATE for the friend declaration
12246 will be an IDENTIFIER_NODE. We are being called from
12247 tsubst_friend_function, and we want only to create a
12248 new decl (R) with appropriate types so that we can call
12249 determine_specialization. */
12252 }
12269 /* If we hit excessive deduction depth, the type is bogus even if
12270 it isn't error_mark_node, so don't build a decl. */
12274 /* We do NOT check for matching decls pushed separately at this
12275 point, as they may not represent instantiations of this
12276 template, and in any case are considered separate under the
12277 discrete model. */
12281 /* Clear out the mangled name and RTL for the instantiation. */
12284 /* Leave DECL_INITIAL set on deleted instantiations. */
12289 /* OpenMP UDRs have the only argument a reference to the declared
12290 type. We want to diagnose if the declared type is a reference,
12291 which is invalid, but as references to references are usually
12292 quietly merged, diagnose it here. */
12294 {
12295 tree argtype
12300 "reference type %qT in "
12304 argtype);
12305 }
12308 /* Type-conversion operator. Reconstruct the name, in
12309 case it's the name of one of the template's parameters. */
12319 {
12323 }
12330 /* If this is an instantiation of a function with internal
12331 linkage, we already know what object file linkage will be
12332 assigned to the instantiation. */
12341 /* We'll re-clone as appropriate in instantiate_template. */
12344 /* If we aren't complaining now, return on error before we register
12345 the specialization so that we'll complain eventually. */
12351 /* When instantiating a constrained member, substitute
12352 into the constraints to create a new constraint. */
12355 {
12358 }
12360 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
12361 this in the special friend case mentioned above where
12362 GEN_TMPL is NULL. */
12364 {
12369 tree new_r
12372 /* We instantiated this while substituting into
12373 the type earlier (template/friend54.C). */
12376 /* We're not supposed to instantiate default arguments
12377 until they are called, for a template. But, for a
12378 declaration like:
12380 template <class T> void f ()
12381 { extern void g(int i = T()); }
12383 we should do the substitution when the template is
12384 instantiated. We handle the member function case in
12385 instantiate_class_template since the default arguments
12386 might refer to other members of the class. */
12391 }
12392 else
12395 /* Copy the list of befriending classes. */
12399 {
12403 }
12406 {
12410 /* If this is an instantiation of a member template, clone it.
12411 If it isn't, that'll be handled by
12412 clone_constructors_and_destructors. */
12415 }
12426 /* Possibly limit visibility based on template args. */
12429 {
12433 }
12442 }
12444 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
12446 static tree
12448 tree lambda_fntype)
12449 {
12450 /* We can get here when processing a member function template,
12451 member class template, or template template parameter. */
12454 tree spec;
12455 tree tmpl_args;
12456 tree full_args;
12457 tree r;
12461 {
12462 /* Template template parameter is treated here. */
12466 /* If we get a real template back, return it. This can happen in
12467 the context of most_specialized_partial_spec. */
12470 else
12471 /* The new TEMPLATE_DECL was built in
12472 reduce_template_parm_level. */
12475 }
12478 {
12479 /* We might already have an instance of this template.
12480 The ARGS are for the surrounding class type, so the
12481 full args contain the tsubst'd args for the context,
12482 plus the innermost args from the template decl. */
12486 /* Because this is a template, the arguments will still be
12487 dependent, even after substitution. If
12488 PROCESSING_TEMPLATE_DECL is not set, the dependency
12489 predicates will short-circuit. */
12497 /* If this is a default template template argument,
12498 tsubst might not have changed anything. */
12506 }
12508 /* Make a new template decl. It will be similar to the
12509 original, but will record the current template arguments.
12510 We also create a new function declaration, which is just
12511 like the old one, but points to this new template, rather
12512 than the old one. */
12517 // Build new template info linking to the original template decl.
12519 {
12522 }
12523 else
12526 /* The template parameters for this new template are all the
12527 template parameters for the old template, except the
12528 outermost level of parameters. */
12531 complain);
12535 {
12536 tree new_type;
12544 /* For a partial specialization, we need to keep pointing to
12545 the primary template. */
12551 }
12552 else
12553 {
12554 tree new_decl;
12558 else
12568 {
12571 }
12572 else
12573 {
12576 }
12577 }
12587 /* Record this non-type partial instantiation. */
12593 }
12595 /* True if FN is the op() for a lambda in an uninstantiated template. */
12597 bool
12599 {
12604 }
12606 /* True if FN is the op() for a lambda regenerated from a lambda in an
12607 uninstantiated template. */
12609 bool
12611 {
12614 }
12616 /* We're instantiating a variable from template function TCTX. Return the
12617 corresponding current enclosing scope. This gets complicated because lambda
12618 functions in templates are regenerated rather than instantiated, but generic
12619 lambda functions are subsequently instantiated. */
12621 static tree
12623 {
12631 {
12642 {
12646 }
12648 }
12650 }
12652 /* Substitute the ARGS into the T, which is a _DECL. Return the
12653 result of the substitution. Issue error and warning messages under
12654 control of COMPLAIN. */
12656 static tree
12658 {
12659 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
12660 location_t saved_loc;
12665 /* Set the filename and linenumber to improve error-reporting. */
12670 {
12680 {
12688 {
12689 /* If there is a local specialization that isn't a
12690 parameter pack, it means that we're doing a "simple"
12691 substitution from inside tsubst_pack_expansion. Just
12692 return the local specialization (which will be a single
12693 parm). */
12700 /* Expand the TYPE_PACK_EXPANSION that provides the types for
12701 the parameters in this function parameter pack. */
12705 {
12708 /* Zero-length parameter packs are boring. Just substitute
12709 into the chain. */
12713 }
12714 else
12715 {
12716 /* All we did was update the type. Make a note of that. */
12719 }
12720 }
12722 /* Loop through all of the parameters we'll build. When T is
12723 a function parameter pack, LEN is the number of expanded
12724 types in EXPANDED_TYPES; otherwise, LEN is 1. */
12727 {
12734 /* We're on the Ith parameter of the function parameter
12735 pack. */
12736 {
12737 /* Get the Ith type. */
12740 /* Rename the parameter to include the index. */
12743 }
12745 /* We're dealing with a normal parameter. */
12753 {
12756 else
12759 }
12769 /* Keep track of the first new parameter we
12770 generate. That's what will be returned to the
12771 caller. */
12775 /* Build a proper chain of parameters when substituting
12776 into a function parameter pack. */
12779 }
12781 /* If cp_unevaluated_operand is set, we're just looking for a
12782 single dummy parameter, so don't keep going. */
12787 /* FIRST_R contains the start of the chain we've built. */
12789 }
12793 {
12800 {
12801 /* This field is a lambda capture pack. Return a TREE_VEC of
12802 the expanded fields to instantiate_class_template_1 and
12803 store them in the specializations hash table as a
12804 NONTYPE_ARGUMENT_PACK so that tsubst_copy can find them. */
12808 {
12811 }
12812 else
12813 {
12814 /* All we did was update the type. Make a note of that. */
12817 }
12818 }
12821 {
12824 {
12828 }
12838 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
12839 number of bits. */
12845 {
12846 /* Set up DECL_TEMPLATE_INFO so that we can get at the
12847 NSDMI in perform_member_init. Still set DECL_INITIAL
12848 so that we know there is one. */
12853 }
12854 /* We don't have to set DECL_CONTEXT here; it is set by
12855 finish_member_declaration. */
12863 }
12866 {
12871 }
12872 }
12876 /* We reach here only for member using decls. We also need to check
12877 uses_template_parms because DECL_DEPENDENT_P is not set for a
12878 using-declaration that designates a member of the current
12879 instantiation (c++/53549). */
12882 {
12886 {
12891 {
12895 {
12898 }
12899 else
12900 {
12903 }
12905 }
12906 }
12907 else
12908 {
12914 else
12915 {
12918 }
12919 }
12920 }
12921 else
12922 {
12925 }
12930 {
12933 tree spec;
12935 tree ctx;
12944 {
12945 /* If this is the canonical decl, we don't have to
12946 mess with instantiations, and often we can't (for
12947 typename, template type parms and such). Note that
12948 TYPE_NAME is not correct for the above test if
12949 we've copied the type for a typedef. */
12955 }
12957 /* Check to see if we already have the specialization we
12958 need. */
12961 {
12962 /* T is a static data member or namespace-scope entity.
12963 We have to substitute into namespace-scope variables
12964 (not just variable templates) because of cases like:
12966 template <class T> void f() { extern T t; }
12968 where the entity referenced is not known until
12969 instantiation time. */
12973 {
12975 complain,
12977 /* If CTX is unchanged, then T is in fact the
12978 specialization we want. That situation occurs when
12979 referencing a static data member within in its own
12980 class. We can use pointer equality, rather than
12981 same_type_p, because DECL_CONTEXT is always
12982 canonical... */
12984 /* ... unless T is a member template; in which
12985 case our caller can be willing to create a
12986 specialization of that template represented
12987 by T. */
12991 }
12994 {
12999 argvec = (coerce_innermost_template_parms
13007 }
13008 }
13009 else
13010 {
13011 /* A local variable. */
13013 /* Subsequent calls to pushdecl will fill this in. */
13015 /* Unless this is a reference to a static variable from an
13016 enclosing function, in which case we need to fill it in now. */
13018 {
13022 }
13024 }
13025 /* If we already have the specialization we need, there is
13026 nothing more to do. */
13028 {
13031 }
13033 /* Create a new node for the specialization we need. */
13036 {
13039 else
13047 {
13048 /* Mask off any template args past the variable's context so we
13049 don't replace the auto with an unrelated argument. */
13053 /* This should never happen with the new lambda instantiation
13054 model, but keep the handling just in case. */
13057 }
13059 }
13061 {
13062 /* Even if the original location is out of scope, the
13063 newly substituted one is not. */
13070 {
13071 /* It may seem that this case cannot occur, since:
13073 typedef void f();
13074 void g() { f x; }
13076 declares a function, not a variable. However:
13078 typedef void f();
13079 template <typename T> void g() { T t; }
13080 template void g<f>();
13082 is an attempt to declare a variable with function
13083 type. */
13085 /* R is not yet sufficiently initialized, so we
13086 just use its name. */
13089 }
13091 /* Wait until cp_finish_decl to set this again, to handle
13092 circular dependency (template/instantiate6.C). */
13097 {
13102 {
13105 }
13107 }
13111 }
13117 /* Clear out the mangled name and RTL for the instantiation. */
13121 /* The initializer must not be expanded until it is required;
13122 see [temp.inst]. */
13126 {
13129 /* Possibly limit visibility based on template args. */
13132 {
13136 }
13138 }
13141 {
13142 /* A static data member declaration is always marked
13143 external when it is declared in-class, even if an
13144 initializer is present. We mimic the non-template
13145 processing here. */
13153 }
13154 else
13155 {
13160 }
13168 /* Preserve a typedef that names a type. */
13170 {
13174 /* An alias template specialization can be dependent
13175 even if its underlying type is not. */
13177 }
13180 }
13185 }
13186 #undef RETURN
13188 out:
13189 /* Restore the file and line information. */
13193 }
13195 /* Substitute into the ARG_TYPES of a function type.
13196 If END is a TREE_CHAIN, leave it and any following types
13197 un-substituted. */
13199 static tree
13201 tree args,
13202 tree end,
13203 tsubst_flags_t complain,
13204 tree in_decl)
13205 {
13206 tree remaining_arg_types;
13210 tree default_arg;
13221 {
13222 /* For a pack expansion, perform substitution on the
13223 entire expression. Later on, we'll handle the arguments
13224 one-by-one. */
13229 /* So that we'll spin through the parameters, one by one. */
13231 else
13232 {
13233 /* We only partially substituted into the parameter
13234 pack. Our type is TYPE_PACK_EXPANSION. */
13237 }
13238 }
13251 {
13253 {
13257 }
13259 }
13260 /* DR 657. */
13264 /* Do array-to-pointer, function-to-pointer conversion, and ignore
13265 top-level qualifiers as required. */
13268 /* We do not substitute into default arguments here. The standard
13269 mandates that they be instantiated only when needed, which is
13270 done in build_over_call. */
13273 /* Except that we do substitute default arguments under tsubst_lambda_expr,
13274 since the new op() won't have any associated template arguments for us
13275 to refer to later. */
13281 {
13282 /* We've instantiated a template before its default arguments
13283 have been parsed. This can happen for a nested template
13284 class, and is not an error unless we require the default
13285 argument in a call of this function. */
13286 remaining_arg_types =
13289 }
13290 else
13291 remaining_arg_types =
13293 }
13296 }
13298 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
13299 *not* handle the exception-specification for FNTYPE, because the
13300 initial substitution of explicitly provided template parameters
13301 during argument deduction forbids substitution into the
13302 exception-specification:
13304 [temp.deduct]
13306 All references in the function type of the function template to the
13307 corresponding template parameters are replaced by the specified tem-
13308 plate argument values. If a substitution in a template parameter or
13309 in the function type of the function template results in an invalid
13310 type, type deduction fails. [Note: The equivalent substitution in
13311 exception specifications is done only when the function is instanti-
13312 ated, at which point a program is ill-formed if the substitution
13313 results in an invalid type.] */
13315 static tree
13317 tree args,
13318 tsubst_flags_t complain,
13319 tree in_decl)
13320 {
13321 tree return_type;
13323 tree fntype;
13325 /* The TYPE_CONTEXT is not used for function/method types. */
13328 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
13329 failure. */
13333 {
13334 /* Substitute the argument types. */
13346 {
13347 /* DR 1207: 'this' is in scope in the trailing return type. */
13349 }
13351 /* Substitute the return type. */
13355 {
13358 }
13359 }
13360 else
13361 /* Substitute the return type. */
13366 /* DR 486 clarifies that creation of a function type with an
13367 invalid return type is a deduction failure. */
13370 {
13372 {
13375 else
13377 }
13379 }
13380 /* And DR 657. */
13385 {
13386 /* Substitute the argument types. */
13391 }
13393 /* Construct a new type node and return it. */
13395 {
13400 }
13401 else
13402 {
13404 /* Don't pick up extra function qualifiers from the basetype. */
13407 {
13408 /* [temp.deduct]
13410 Type deduction may fail for any of the following
13411 reasons:
13413 -- Attempting to create "pointer to member of T" when T
13414 is not a class type. */
13417 r);
13419 }
13424 }
13431 }
13433 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
13434 ARGS into that specification, and return the substituted
13435 specification. If there is no specification, return NULL_TREE. */
13437 static tree
13439 tree args,
13440 tsubst_flags_t complain,
13441 tree in_decl,
13443 {
13444 tree specs;
13445 tree new_specs;
13450 {
13451 /* A noexcept-specifier. */
13456 {
13457 /* Defer instantiation of noexcept-specifiers to avoid
13458 excessive instantiations (c++/49107). */
13461 {
13462 /* We already partially instantiated this member template,
13463 so combine the new args with the old. */
13468 }
13469 else
13470 {
13473 }
13474 }
13475 else
13476 new_specs = tsubst_copy_and_build
13480 }
13482 {
13485 else
13487 {
13488 tree spec;
13493 {
13494 /* Expand the pack expansion type. */
13497 in_decl);
13503 else
13504 {
13505 /* We're substituting into a member template, so
13506 we got a TYPE_PACK_EXPANSION back. Add that
13507 expansion and move on. */
13511 expanded_specs,
13512 complain);
13515 }
13516 }
13519 {
13522 else
13527 complain);
13528 }
13531 }
13532 }
13534 }
13536 /* Take the tree structure T and replace template parameters used
13537 therein with the argument vector ARGS. IN_DECL is an associated
13538 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
13539 Issue error and warning messages under control of COMPLAIN. Note
13540 that we must be relatively non-tolerant of extensions here, in
13541 order to preserve conformance; if we allow substitutions that
13542 should not be allowed, we may allow argument deductions that should
13543 not succeed, and therefore report ambiguous overload situations
13544 where there are none. In theory, we could allow the substitution,
13545 but indicate that it should have failed, and allow our caller to
13546 make sure that the right thing happens, but we don't try to do this
13547 yet.
13549 This function is used for dealing with types, decls and the like;
13550 for expressions, use tsubst_expr or tsubst_copy. */
13552 tree
13554 {
13577 else
13582 /* Reuse typedefs. We need to do this to handle dependent attributes,
13583 such as attribute aligned. */
13586 {
13590 {
13591 /* DECL represents an alias template and we want to
13592 instantiate it. */
13596 }
13600 {
13604 }
13609 else
13610 /* The typedef is from a non-template context. */
13614 {
13616 r = cp_build_qualified_type_real
13620 }
13621 else
13622 {
13623 /* We don't have an instantiation yet, so drop the typedef. */
13628 }
13629 }
13646 {
13672 {
13678 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
13679 needed. */
13685 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
13686 with TREE_SIDE_EFFECTS that indicates this is not an integral
13687 constant expression. */
13690 {
13693 }
13696 }
13702 {
13708 /* Early in template argument deduction substitution, we don't
13709 want to reduce the level of 'auto', or it will be confused
13710 with a normal template parm in subsequent deduction. */
13722 {
13726 {
13727 /* See through ARGUMENT_PACK_SELECT arguments. */
13729 /* If the selected argument is an expansion E, that most
13730 likely means we were called from
13731 gen_elem_of_pack_expansion_instantiation during the
13732 substituting of pack an argument pack (which Ith
13733 element is a pack expansion, where I is
13734 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
13735 In this case, the Ith element resulting from this
13736 substituting is going to be a pack expansion, which
13737 pattern is the pattern of E. Let's return the
13738 pattern of E, and
13739 gen_elem_of_pack_expansion_instantiation will
13740 build the resulting pack expansion from it. */
13742 {
13743 /* Make sure we aren't throwing away arg info. */
13746 }
13747 }
13748 }
13753 {
13755 /* If ARG is an argument pack, we don't actually want to
13756 perform a substitution here, because substitutions
13757 for argument packs are only done
13758 element-by-element. We can get to this point when
13759 substituting the type of a non-type template
13760 parameter pack, when that type actually contains
13761 template parameter packs from an outer template, e.g.,
13763 template<typename... Types> struct A {
13764 template<Types... Values> struct B { };
13765 }; */
13769 {
13775 return cp_build_qualified_type_real
13777 }
13779 {
13780 /* We are processing a type constructed from a
13781 template template parameter. */
13792 /* Consider this code:
13794 template <template <class> class Template>
13795 struct Internal {
13796 template <class Arg> using Bind = Template<Arg>;
13797 };
13799 template <template <class> class Template, class Arg>
13800 using Instantiate = Template<Arg>; //#0
13802 template <template <class> class Template,
13803 class Argument>
13804 using Bind =
13805 Instantiate<Internal<Template>::template Bind,
13806 Argument>; //#1
13808 When #1 is parsed, the
13809 BOUND_TEMPLATE_TEMPLATE_PARM representing the
13810 parameter `Template' in #0 matches the
13811 UNBOUND_CLASS_TEMPLATE representing the argument
13812 `Internal<Template>::template Bind'; We then want
13813 to assemble the type `Bind<Argument>' that can't
13814 be fully created right now, because
13815 `Internal<Template>' not being complete, the Bind
13816 template cannot be looked up in that context. So
13817 we need to "store" `Bind<Argument>' for later
13818 when the context of Bind becomes complete. Let's
13819 store that in a TYPENAME_TYPE. */
13823 argvec),
13824 typename_type,
13825 complain);
13827 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
13828 are resolving nested-types in the signature of a
13829 member function templates. Otherwise ARG is a
13830 TEMPLATE_DECL and is the real template to be
13831 instantiated. */
13839 complain);
13840 return cp_build_qualified_type_real
13842 }
13845 else
13846 /* TEMPLATE_PARM_INDEX. */
13848 }
13851 /* This can happen during the attempted tsubst'ing in
13852 unify. This means that we don't yet have any information
13853 about the template parameter in question. */
13856 /* If we get here, we must have been looking at a parm for a
13857 more deeply nested template. Make a new version of this
13858 template parameter, but with a lower level. */
13860 {
13865 {
13867 r = cp_build_qualified_type_real
13871 }
13878 /* Break infinite recursion when substituting the constraints
13880 else
13881 {
13892 {
13893 /* Propagate constraints on placeholders. */
13898 {
13902 }
13903 }
13906 /* We have reduced the level of the template
13907 template parameter, but not the levels of its
13908 template parameters, so canonical_type_parameter
13909 will not be able to find the canonical template
13910 template parameter for this level. Thus, we
13911 require structural equality checking to compare
13912 TEMPLATE_TEMPLATE_PARMs. */
13916 else
13920 {
13922 /* We might need to substitute into the types of non-type
13923 template parameters. */
13935 }
13936 }
13940 /* OK, now substitute the type of the non-type parameter. We
13941 couldn't do it earlier because it might be an auto parameter,
13942 and we wouldn't need to if we had an argument. */
13951 }
13954 }
13957 {
13965 {
13969 }
13972 {
13976 }
13979 {
13983 }
13989 }
13992 /* We should never be tsubsting a binfo. */
13996 /* A vector of template arguments. */
14002 {
14006 /* [temp.deduct]
14008 Type deduction may fail for any of the following
14009 reasons:
14011 -- Attempting to create a pointer to reference type.
14012 -- Attempting to create a reference to a reference type or
14013 a reference to void.
14015 Core issue 106 says that creating a reference to a reference
14016 during instantiation is no longer a cause for failure. We
14017 only enforce this check in strict C++98 mode. */
14021 {
14024 /* We keep track of the last time we issued this error
14025 message to avoid spewing a ton of messages during a
14026 single bad template instantiation. */
14029 {
14034 else
14037 }
14040 }
14044 {
14046 {
14049 type);
14050 else
14052 type);
14053 }
14055 }
14057 {
14061 }
14063 /* In C++0x, during template argument substitution, when there is an
14064 attempt to create a reference to a reference type, reference
14065 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
14067 "If a template-argument for a template-parameter T names a type
14068 that is a reference to a type A, an attempt to create the type
14069 'lvalue reference to cv T' creates the type 'lvalue reference to
14070 A,' while an attempt to create the type type rvalue reference to
14071 cv T' creates the type T"
14072 */
14073 r = cp_build_reference_type
14076 else
14081 /* Will this ever be needed for TYPE_..._TO values? */
14085 }
14087 {
14090 {
14091 /* [temp.deduct]
14093 Type deduction may fail for any of the following
14094 reasons:
14096 -- Attempting to create "pointer to member of T" when T
14097 is not a class type. */
14101 }
14103 {
14107 }
14109 {
14113 }
14116 {
14117 /* The type of the implicit object parameter gets its
14118 cv-qualifiers from the FUNCTION_TYPE. */
14119 tree memptr;
14120 tree method_type
14125 complain);
14126 }
14127 else
14130 complain);
14131 }
14134 {
14135 tree fntype;
14136 tree specs;
14141 /* Substitute the exception specification. */
14149 }
14151 {
14156 /* As an optimization, we avoid regenerating the array type if
14157 it will obviously be the same as T. */
14161 /* These checks should match the ones in create_array_type_for_decl.
14163 [temp.deduct]
14165 The deduction may fail for any of the following reasons:
14167 -- Attempting to create an array with an element type that
14168 is void, a function type, or a reference type, or [DR337]
14169 an abstract class type. */
14175 {
14179 }
14187 {
14190 }
14193 }
14196 {
14208 {
14212 }
14214 {
14215 /* Normally, make_typename_type does not require that the CTX
14216 have complete type in order to allow things like:
14218 template <class T> struct S { typename S<T>::X Y; };
14220 But, such constructs have already been resolved by this
14221 point, so here CTX really should have complete type, unless
14222 it's a partial instantiation. */
14225 {
14229 }
14230 }
14237 {
14240 }
14243 {
14245 {
14249 else
14251 }
14253 {
14257 else
14259 }
14260 }
14262 return cp_build_qualified_type_real
14264 }
14267 {
14279 }
14282 {
14283 tree type;
14299 complain);
14300 }
14303 {
14304 tree type;
14315 {
14317 {
14321 }
14324 }
14335 else
14336 {
14340 /* In a template ~id could be either a complement expression
14341 or an unqualified-id naming a destructor; if instantiating
14342 it produces an expression, it's not an id-expression or
14343 member access. */
14346 }
14351 }
14354 {
14358 }
14362 {
14363 tree r;
14367 else
14375 }
14390 /* We should use one of the expression tsubsts for these codes. */
14396 }
14397 }
14399 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
14400 expression on the left-hand side of the "." or "->" operator. A
14401 baselink indicates a function from a base class. Both the
14402 BASELINK_ACCESS_BINFO and the base class referenced may indicate
14403 bases of the template class, rather than the instantiated class.
14404 In addition, lookups that were not ambiguous before may be
14405 ambiguous now. Therefore, we perform the lookup again. */
14407 static tree
14410 {
14423 {
14430 }
14438 {
14443 }
14445 /* If lookup found a single function, mark it as used at this point.
14446 (If it lookup found multiple functions the one selected later by
14447 overload resolution will be marked as used at that point.) */
14455 {
14456 /* Add back the template arguments, if present. */
14462 /* Update the conversion operator type. */
14464 }
14470 {
14472 qualifying_scope,
14473 object_type);
14475 /* We need to call adjust_result_of_qualified_name_lookup in case the
14476 destructor names a base class, but we unset BASELINK_QUALIFIED_P
14477 so that we still get virtual function binding. */
14479 }
14482 }
14484 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
14485 true if the qualified-id will be a postfix-expression in-and-of
14486 itself; false if more of the postfix-expression follows the
14487 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
14488 of "&". */
14490 static tree
14494 {
14495 tree expr;
14496 tree scope;
14497 tree name;
14499 tree template_args;
14504 /* Figure out what name to look up. */
14507 {
14517 }
14518 else
14519 {
14522 }
14524 /* Substitute into the qualifying scope. When there are no ARGS, we
14525 are just trying to simplify a non-dependent expression. In that
14526 case the qualifying scope may be dependent, and, in any case,
14527 substituting will not help. */
14530 {
14533 }
14534 else
14538 {
14545 }
14548 {
14550 {
14551 /* A BIT_NOT_EXPR is used to represent a destructor. */
14553 {
14557 }
14558 else
14561 }
14562 else
14566 {
14568 {
14572 }
14574 }
14575 }
14578 {
14580 scope);
14581 /* Remember that there was a reference to this entity. */
14584 }
14587 {
14593 }
14596 {
14599 complain);
14600 else
14602 }
14608 {
14609 expr = (adjust_result_of_qualified_name_lookup
14611 expr = (finish_qualified_id_expr
14615 }
14617 /* Expressions do not generally have reference type. */
14619 /* However, if we're about to form a pointer-to-member, we just
14620 want the referenced member referenced. */
14628 }
14630 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
14631 initializer, DECL is the substituted VAR_DECL. Other arguments are as
14632 for tsubst. */
14634 static tree
14637 {
14644 {
14645 /* If we had an initializer but it
14646 instantiated to nothing,
14647 value-initialize the object. This will
14648 only occur when the initializer was a
14649 pack expansion where the parameter packs
14650 used in that expansion were of length
14651 zero. */
14653 complain);
14658 }
14661 }
14663 /* Like tsubst, but deals with expressions. This function just replaces
14664 template parms; to finish processing the resultant expression, use
14665 tsubst_copy_and_build or tsubst_expr. */
14667 static tree
14669 {
14671 tree r;
14679 {
14684 {
14685 /* We get here for a use of 'this' in an NSDMI. */
14689 /* This can happen for a parameter name used later in a function
14690 declaration (such as in a late-specified return type). Just
14691 make a dummy decl, since it's only used for its type. */
14694 /* Give it the template pattern as its context; its true context
14695 hasn't been instantiated yet and this is good enough for
14696 mangling. */
14698 }
14707 {
14708 tree enum_type;
14709 tree v;
14713 /* There is no need to substitute into namespace-scope
14714 enumerators. */
14717 /* If ARGS is NULL, then T is known to be non-dependent. */
14721 /* Unfortunately, we cannot just call lookup_name here.
14722 Consider:
14724 template <int I> int f() {
14725 enum E { a = I };
14726 struct S { void g() { E e = a; } };
14727 };
14729 When we instantiate f<7>::S::g(), say, lookup_name is not
14730 clever enough to find f<7>::a. */
14731 enum_type
14741 /* We didn't find the name. That should never happen; if
14742 name-lookup found it during preliminary parsing, we
14743 should find it again here during instantiation. */
14745 }
14750 {
14751 /* Check for a local specialization set up by
14752 tsubst_pack_expansion. */
14754 {
14758 }
14760 /* When retrieving a capture pack from a generic lambda, remove the
14761 lambda call op's own template argument list from ARGS. Only the
14762 template arguments active for the closure type should be used to
14763 retrieve the pack specialization. */
14769 /* Otherwise return the full NONTYPE_ARGUMENT_PACK that
14770 tsubst_decl put in the hash table. */
14772 }
14775 {
14776 tree ctx;
14781 {
14784 {
14788 }
14790 }
14791 }
14801 {
14804 {
14805 /* First try name lookup to find the instantiation. */
14808 {
14809 /* Make sure that the one we found is the one we want. */
14813 }
14817 else
14818 {
14819 /* This can happen for a variable used in a
14820 late-specified return type of a local lambda, or for a
14821 local static or constant. Building a new VAR_DECL
14822 should be OK in all those cases. */
14825 /* Avoid infinite recursion (79640). */
14828 {
14829 /* We can't call cp_finish_decl, so handle the
14830 initializer by hand. */
14845 }
14852 }
14853 /* Remember this for subsequent uses. */
14856 }
14857 }
14858 else
14868 /* An OVERLOAD will always be a non-dependent overload set; an
14869 overload set from function scope will just be represented with an
14870 IDENTIFIER_NODE, and from class scope with a BASELINK. */
14872 /* We must have marked any lookups as persistent. */
14888 {
14889 /* Template template argument like the following example need
14890 special treatment:
14892 template <template <class> class TT> struct C {};
14893 template <class T> struct D {
14894 template <class U> struct E {};
14895 C<E> c; // #1
14896 };
14897 D<int> d; // #2
14899 We are processing the template argument `E' in #1 for
14900 the template instantiation #2. Originally, `E' is a
14901 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
14902 have to substitute this with one having context `D<int>'. */
14906 {
14907 /* When rewriting a constructor into a deduction guide, a
14908 non-dependent name can become dependent, so memtmpl<args>
14909 becomes context::template memtmpl<args>. */
14913 }
14915 }
14916 else
14917 /* Ordinary template template argument. */
14928 {
14932 }
14937 {
14946 /* We only want to compute the number of arguments. */
14949 else
14956 {
14958 /* Set TREE_USED for the benefit of -Wunused. */
14962 }
14970 {
14975 else
14981 else
14984 }
14985 else
14987 }
14989 {
14997 }
14998 /* Fall through */
15014 {
15018 }
15021 {
15022 tree object;
15023 tree name;
15028 {
15032 }
15035 {
15045 }
15050 in_decl);
15051 else
15054 }
15092 {
15096 }
15099 {
15104 }
15107 {
15111 }
15114 {
15122 }
15128 {
15135 }
15138 {
15145 }
15148 {
15155 }
15158 {
15159 /* Substituted template arguments */
15168 }
15171 {
15191 }
15216 /* Fall through. */
15219 {
15222 }
15223 else
15227 /* This is handled by tsubst_copy_and_build. */
15231 {
15235 }
15238 /* We shouldn't have built any of these during initial template
15239 generation. Instead, they should be built during instantiation
15240 in response to the saved STMT_IS_FULL_EXPR_P setting. */
15244 {
15254 }
15272 {
15273 /* Instantiate any typedefs in the type. */
15278 }
15281 /* These can sometimes show up in a partial instantiation, but never
15282 involve template parms. */
15298 /* We shouldn't get here, but keep going if !flag_checking. */
15302 }
15303 }
15305 /* Helper function for tsubst_omp_clauses, used for instantiation of
15306 OMP_CLAUSE_DECL of clauses. */
15308 static tree
15310 tree in_decl)
15311 {
15315 /* Handle an OpenMP array section represented as a TREE_LIST (or
15316 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15317 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15318 TREE_LIST. We can handle it exactly the same as an array section
15319 (purpose, value, and a chain), even though the nomenclature
15320 (low_bound, length, etc) is different. */
15322 {
15323 tree low_bound
15329 in_decl);
15338 }
15341 /* Undo convert_from_reference tsubst_expr could have called. */
15347 }
15349 /* Like tsubst_copy, but specifically for OpenMP clauses. */
15351 static tree
15354 {
15359 {
15365 {
15368 {
15374 }
15375 /* FALLTHRU */
15390 in_decl);
15422 {
15425 {
15432 }
15433 else
15435 }
15438 in_decl);
15444 in_decl);
15452 in_decl);
15454 {
15457 }
15462 else
15465 in_decl,
15489 }
15492 {
15502 /* tsubst_expr on SCOPE_REF results in returning
15503 finish_non_static_data_member result. Undo that here. */
15507 {
15512 {
15516 CASE_CONVERT:
15525 /* FALLTHRU */
15529 }
15530 }
15536 {
15539 {
15542 }
15543 }
15547 }
15548 }
15552 {
15557 {
15560 }
15561 }
15563 }
15565 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
15567 static tree
15569 tree in_decl)
15570 {
15571 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
15591 {
15594 else
15595 {
15599 }
15600 }
15605 #undef RECUR
15606 }
15608 /* Used to temporarily communicate the list of #pragma omp parallel
15609 clauses to #pragma omp for instantiation if they are combined
15610 together. */
15614 /* Substitute one OMP_FOR iterator. */
15616 static void
15621 {
15622 #define RECUR(NODE) \
15623 tsubst_expr ((NODE), args, complain, in_decl, \
15624 integral_constant_expression_p)
15631 {
15634 }
15640 {
15641 /* We need to jump through some hoops to handle declarations in the
15642 init-statement, since we might need to handle auto deduction,
15643 but we need to keep control of initialization. */
15647 }
15648 else
15649 {
15651 {
15654 {
15658 {
15662 CASE_CONVERT:
15670 {
15673 }
15674 /* FALLTHRU */
15678 }
15679 }
15680 }
15681 else
15683 }
15694 {
15696 {
15697 /* Declare the variable, but don't let that initialize it. */
15702 }
15707 {
15712 }
15713 else
15720 }
15723 {
15724 /* Declare and initialize the variable. */
15727 }
15729 {
15733 {
15735 {
15741 {
15744 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
15749 }
15752 {
15754 decl);
15756 }
15759 {
15761 decl);
15763 }
15764 else
15766 }
15769 }
15771 {
15776 {
15779 }
15780 }
15781 }
15784 {
15788 }
15789 else
15793 {
15804 {
15812 }
15813 else
15819 {
15825 }
15829 {
15837 }
15838 else
15844 }
15850 #undef RECUR
15851 }
15853 /* Helper function of tsubst_expr, find OMP_TEAMS inside
15854 of OMP_TARGET's body. */
15856 static tree
15858 {
15861 {
15870 }
15872 }
15874 /* Helper function for tsubst_expr. For decomposition declaration
15875 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
15876 also the corresponding decls representing the identifiers
15877 of the decomposition declaration. Return DECL if successful
15878 or error_mark_node otherwise, set *FIRST to the first decl
15879 in the list chained through DECL_CHAIN and *CNT to the number
15880 of such decls. */
15882 static tree
15886 {
15891 decl2
15896 {
15898 {
15901 }
15918 {
15921 }
15922 else
15924 }
15927 }
15929 /* Like tsubst_copy for expressions, etc. but also does semantic
15930 processing. */
15932 tree
15935 {
15936 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
15937 #define RECUR(NODE) \
15938 tsubst_expr ((NODE), args, complain, in_decl, \
15939 integral_constant_expression_p)
15942 tree r;
15943 location_t loc;
15955 {
15957 {
15958 tree_stmt_iterator i;
15962 }
15977 else
15987 {
15989 tree init;
15995 {
16005 else
16007 }
16009 {
16010 /* Don't build up decls for a variadic capture proxy, we'll
16011 instantiate the elements directly as needed. */
16013 }
16016 {
16017 /* We're in tsubst_lambda_expr, we've already inserted a new
16018 capture proxy, so look it up and register it. */
16024 }
16027 /* Don't copy the old closure; we'll create a new one in
16028 tsubst_lambda_expr. */
16030 else
16031 {
16035 {
16036 /* By marking the declaration as instantiated, we avoid
16037 trying to instantiate it. Since instantiate_decl can't
16038 handle local variables, and since we've already done
16039 all that needs to be done, that's the right thing to
16040 do. */
16045 /* Anonymous aggregates are a special case. */
16048 {
16051 {
16055 }
16057 }
16063 {
16068 }
16069 else
16070 {
16075 {
16076 /* For __PRETTY_FUNCTION__ we have to adjust the
16077 initializer. */
16081 }
16082 else
16086 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
16092 {
16094 tree first;
16100 }
16101 }
16102 }
16103 }
16106 }
16121 {
16129 {
16131 tree first;
16136 }
16137 else
16142 }
16168 else
16169 {
16176 }
16182 {
16191 }
16199 else
16207 else
16228 {
16235 }
16239 {
16241 tree label;
16248 }
16254 /* Computed goto's must be tsubst'd into. On the other hand,
16255 non-computed gotos must not be; the identifier in question
16256 will have no binding. */
16258 else
16264 {
16280 }
16285 {
16290 }
16291 else
16292 {
16297 else
16304 else
16310 else
16312 }
16316 {
16320 {
16322 /* Prevent instantiate_decl from trying to instantiate
16323 this variable. We've already done all that needs to be
16324 done. */
16327 }
16332 }
16338 {
16339 /* Local classes are not independent templates; they are
16340 instantiated along with their containing function. And this
16341 way we don't have to deal with pushing out of one local class
16342 to instantiate a member of another local class. */
16343 /* Closures are handled by the LAMBDA_EXPR. */
16353 }
16357 {
16358 tree condition;
16361 condition =
16363 args,
16372 }
16378 in_decl);
16415 {
16430 in_decl);
16432 {
16439 }
16451 integral_constant_expression_p);
16462 else
16463 {
16471 }
16475 }
16480 /* FALLTHRU */
16487 in_decl);
16504 in_decl);
16515 {
16518 {
16519 /* For combined target teams, ensure the num_teams and
16520 thread_limit clause expressions are evaluated on the host,
16521 before entering the target construct. */
16522 tree c;
16528 {
16537 OMP_CLAUSE_FIRSTPRIVATE);
16541 }
16542 }
16543 }
16603 {
16608 {
16611 }
16617 }
16618 else
16619 {
16626 {
16629 }
16632 {
16637 {
16640 }
16646 }
16647 else
16648 {
16652 }
16655 }
16659 {
16665 {
16669 {
16674 }
16678 }
16679 else
16680 {
16685 }
16686 }
16690 {
16694 }
16714 /* If the first operand was a statement, we're done with it. */
16718 complain));
16730 integral_constant_expression_p));
16731 }
16734 out:
16737 #undef RECUR
16738 #undef RETURN
16739 }
16741 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
16742 function. For description of the body see comment above
16743 cp_parser_omp_declare_reduction_exprs. */
16745 static void
16747 {
16753 tree_stmt_iterator tsi;
16764 {
16783 }
16785 {
16805 }
16806 }
16808 /* T is a postfix-expression that is not being used in a function
16809 call. Return the substituted version of T. */
16811 static tree
16813 tsubst_flags_t complain,
16814 tree in_decl)
16815 {
16819 else
16825 }
16827 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
16828 instantiation context. Instantiating a pack expansion containing a lambda
16829 might result in multiple lambdas all based on the same lambda in the
16830 template. */
16832 tree
16834 {
16848 else
16856 {
16868 else
16873 {
16882 }
16883 else
16884 {
16890 }
16891 }
16895 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
16913 else
16914 {
16915 /* Fix the type of 'this'. */
16921 {
16925 }
16926 else
16927 {
16931 }
16933 /* Let finish_function set this. */
16954 /* The capture list was built up in reverse order; fix that now. */
16961 }
16968 }
16970 /* Like tsubst but deals with expressions and performs semantic
16971 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
16973 tree
16975 tree args,
16976 tsubst_flags_t complain,
16977 tree in_decl,
16980 {
16981 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
16982 #define RECUR(NODE) \
16983 tsubst_copy_and_build (NODE, args, complain, in_decl, \
16985 integral_constant_expression_p)
16988 location_t loc;
16997 /* N3276 decltype magic only applies to calls at the top level or on the
16998 right side of a comma. */
17003 {
17006 /* Fall through. */
17008 {
17009 tree decl;
17010 cp_id_kind idk;
17015 {
17018 }
17020 /* Look up the name. */
17023 /* By convention, expressions use ERROR_MARK_NODE to indicate
17024 failure, not NULL_TREE. */
17030 integral_constant_expression_p,
17038 input_location);
17042 {
17046 }
17048 }
17051 {
17052 tree object;
17062 {
17067 }
17073 {
17076 }
17077 else
17084 else
17086 }
17089 {
17093 {
17094 /* A type conversion to reference type will be enclosed in
17095 such an indirect ref, but the substitution of the cast
17096 will have also added such an indirect ref. */
17099 }
17100 else
17108 }
17111 {
17115 }
17118 {
17125 flags));
17126 }
17129 {
17133 }
17140 {
17141 tree type;
17147 {
17152 }
17158 {
17176 }
17179 }
17213 else
17215 in_decl);
17250 {
17257 tree r = build_x_binary_op
17259 op0,
17261 ? ERROR_MARK
17263 op1,
17265 ? ERROR_MARK
17273 }
17276 {
17280 }
17293 {
17302 }
17307 /* Fall through */
17310 {
17311 tree r;
17317 {
17318 /* When there are no ARGS, we are trying to evaluate a
17319 non-dependent expression from the parser. Trying to do
17320 the substitutions may not work. */
17323 }
17324 else
17325 {
17330 else
17333 /*integral_constant_expression_p=*/
17337 }
17341 else
17345 {
17347 {
17349 {
17353 }
17354 else
17358 }
17360 }
17362 }
17365 {
17375 }
17391 {
17395 tree r = build_x_modify_expr
17398 /* TREE_NO_WARNING must be set if either the expression was
17399 parenthesized or it uses an operator such as >>= rather
17400 than plain assignment. In the former case, it was already
17401 set and must be copied. In the latter case,
17402 build_x_modify_expr sets it and it must not be reset
17403 here. */
17408 }
17413 /* Remember that there was a reference to this entity. */
17420 {
17425 tree ret;
17429 else
17430 {
17434 }
17436 /* If there was an initializer in the original tree, but it
17437 instantiated to an empty list, then we should pass a
17438 non-NULL empty vector to tell build_new that it was an
17439 empty initializer() rather than no initializer. This can
17440 only happen when the initializer is a pack expansion whose
17441 parameter packs are of length zero. */
17444 else
17445 {
17449 else
17450 {
17453 }
17454 }
17460 complain);
17468 }
17471 {
17477 complain));
17478 }
17481 {
17485 integral_constant_expression_p);
17487 op0,
17490 }
17493 {
17494 tree function;
17499 tree ret;
17502 /* Internal function with no arguments. */
17506 /* When we parsed the expression, we determined whether or
17507 not Koenig lookup should be performed. */
17510 {
17513 }
17515 {
17520 }
17522 {
17523 /* Do nothing; calling tsubst_copy_and_build on an identifier
17524 would incorrectly perform unqualified lookup again.
17526 Note that we can also have an IDENTIFIER_NODE if the earlier
17527 unqualified lookup found a member function; in that case
17528 koenig_p will be false and we do want to do the lookup
17529 again to find the instantiated member function.
17531 FIXME but doing that causes c++/15272, so we need to stop
17532 using IDENTIFIER_NODE in that situation. */
17534 }
17535 else
17536 {
17538 {
17544 }
17545 else
17550 /* Avoid error about taking the address of a constructor. */
17554 in_decl,
17556 integral_constant_expression_p);
17560 }
17565 {
17570 else
17571 {
17572 /* Expand the pack expansion and push each entry onto
17573 CALL_ARGS. */
17576 {
17581 {
17586 }
17587 }
17588 else
17589 {
17590 /* A partial substitution. Add one entry. */
17592 }
17593 }
17594 }
17596 /* We do not perform argument-dependent lookup if normal
17597 lookup finds a non-function, in accordance with the
17598 expected resolution of DR 218. */
17601 /* If lookup found a member function, the Koenig lookup is
17602 not appropriate, even if an unqualified-name was used
17603 to denote the function. */
17606 /* Only do this when substitution turns a dependent call
17607 into a non-dependent call. */
17615 {
17617 {
17618 /* For backwards compatibility and good diagnostics, try
17619 the unqualified lookup again if we aren't in SFINAE
17620 context. */
17621 tree unq = (tsubst_copy_and_build
17623 integral_constant_expression_p));
17625 {
17628 }
17631 {
17632 /* In a lambda fn, we have to be careful to not
17633 introduce new this captures. Legacy code can't
17634 be using lambdas anyway, so it's ok to be
17635 stricter. */
17640 "and no declarations were found by "
17641 "argument-dependent lookup at the point "
17648 else
17652 {
17663 {
17665 input_location);
17667 "declarations in dependent base %qT are "
17673 else
17677 }
17678 else
17680 "%qD declared here, later in the "
17683 {
17686 }
17687 }
17690 }
17691 }
17693 {
17698 }
17699 }
17701 /* Remember that there was a reference to this entity. */
17705 {
17708 }
17710 /* Put back tf_decltype for the actual call. */
17715 {
17719 {
17721 "wrong number of arguments to "
17724 }
17725 else
17727 input_location),
17732 /* Unsupported internal function with arguments. */
17734 }
17737 complain);
17739 {
17754 complain);
17755 else
17756 ret = (build_new_method_call
17761 complain));
17762 }
17763 else
17766 koenig_p,
17767 complain);
17772 {
17778 {
17784 {
17786 /* The thunk location is not interesting. */
17788 }
17789 }
17790 }
17793 }
17796 {
17802 {
17804 {
17809 }
17810 else
17811 {
17816 }
17818 }
17819 else
17820 {
17823 }
17827 }
17830 {
17835 input_location));
17836 }
17839 {
17847 {
17848 /* We have pack expansions, so expand those and
17849 create a new list out of it. */
17852 tree chain;
17855 /* Expand the argument expressions. */
17863 /* Build the rest of the list. */
17868 /* Determine the number of arguments. */
17870 {
17873 }
17876 else
17877 {
17878 /* Since we only performed a partial substitution into
17879 the argument pack, we only RETURN (a single list
17880 node. */
17887 }
17889 /* Convert the argument vectors into a TREE_LIST */
17892 {
17893 /* Grab the Ith values. */
17894 i--;
17897 value
17901 /* Build the list (backwards). */
17903 }
17906 }
17922 }
17925 {
17926 tree object;
17927 tree object_type;
17928 tree member;
17929 tree r;
17933 /* Remember that there was a reference to this entity. */
17944 else
17950 {
17955 }
17959 {
17961 {
17966 {
17969 }
17971 {
17976 }
17977 }
17978 }
17981 {
17982 /* Lookup the template functions now that we know what the
17983 scope is. */
17991 {
17994 args);
17995 member = (adjust_result_of_qualified_name_lookup
17997 object_type));
17998 }
17999 else
18000 {
18002 input_location);
18004 }
18005 }
18009 {
18011 {
18015 else
18018 }
18020 }
18024 complain);
18028 }
18035 {
18043 tree r;
18048 /* digest_init will do the wrong thing if we let it. */
18052 /* We do not want to process the index of aggregate
18053 initializers as they are identifier nodes which will be
18054 looked up by digest_init. */
18060 {
18062 /* An identifier index is looked up in the type
18063 being initialized, not the current scope. */
18068 {
18069 /* Substitute into the pack expansion. */
18071 in_decl);
18075 ;
18077 /* Just move the argument into place. */
18079 else
18080 {
18081 /* Update the length of the final CONSTRUCTOR
18082 arguments vector, and note that we will need to
18083 copy.*/
18086 }
18087 }
18088 else
18090 }
18093 {
18098 {
18100 {
18105 }
18106 else
18108 }
18109 }
18115 {
18120 }
18124 }
18127 {
18130 {
18133 }
18134 else
18135 {
18138 }
18139 }
18145 {
18146 /* We don't build decls for an instantiation of a
18147 variadic capture proxy, we instantiate the elements
18148 when needed. */
18151 }
18152 /* Fall through */
18155 {
18157 /* ??? We're doing a subset of finish_id_expression here. */
18159 && !processing_template_decl
18160 && !cp_unevaluated_operand
18163 {
18165 /* Replace an evaluated use of the thread_local variable with
18166 a call to its wrapper. */
18168 }
18173 /* If the original type was a reference, we'll be wrapped in
18174 the appropriate INDIRECT_REF. */
18177 }
18180 {
18184 }
18187 {
18188 tree object_ptr
18195 }
18202 {
18213 }
18216 {
18222 integral_constant_expression_p);
18226 /* If the resulting list of expression statement is empty,
18227 fold it further into void_node. */
18232 }
18235 {
18239 }
18242 /* We can get here for a constant initializer of non-dependent type.
18243 FIXME stop folding in cp_parser_initializer_clause. */
18244 {
18246 complain);
18248 }
18252 integral_constant_expression_p));
18258 {
18263 complain));
18264 }
18270 /* Handle Objective-C++ constructs, if appropriate. */
18271 {
18272 tree subst
18277 }
18279 }
18281 #undef RECUR
18282 #undef RETURN
18283 out:
18286 }
18288 /* Verify that the instantiated ARGS are valid. For type arguments,
18289 make sure that the type's linkage is ok. For non-type arguments,
18290 make sure they are constants if they are integral or enumerations.
18291 Emit an error under control of COMPLAIN, and return TRUE on error. */
18293 static bool
18295 {
18299 {
18309 }
18311 {
18312 /* [basic.link]: A name with no linkage (notably, the name
18313 of a class or enumeration declared in a local scope)
18314 shall not be used to declare an entity with linkage.
18315 This implies that names with no linkage cannot be used as
18316 template arguments
18318 DR 757 relaxes this restriction for C++0x. */
18323 {
18324 /* DR 488 makes use of a type with no linkage cause
18325 type deduction to fail. */
18327 {
18330 else
18333 }
18335 }
18336 /* In order to avoid all sorts of complications, we do not
18337 allow variably-modified types as template arguments. */
18339 {
18343 }
18344 }
18345 /* Class template and alias template arguments should be OK. */
18347 ;
18348 /* A non-type argument of integral or enumerated type must be a
18349 constant. */
18354 {
18358 }
18360 }
18362 static bool
18364 {
18369 {
18372 }
18376 }
18378 /* We're out of SFINAE context now, so generate diagnostics for the access
18379 errors we saw earlier when instantiating D from TMPL and ARGS. */
18381 static void
18383 {
18395 }
18397 /* Instantiate the indicated variable, function, or alias template TMPL with
18398 the template arguments in TARG_PTR. */
18400 static tree
18402 {
18404 tree fndecl;
18405 tree gen_tmpl;
18406 tree spec;
18414 /* If this function is a clone, handle it specially. */
18416 {
18417 tree spec;
18418 tree clone;
18420 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
18421 DECL_CLONED_FUNCTION. */
18427 /* Look for the clone. */
18431 /* We should always have found the clone by now. */
18434 }
18439 /* Check to see if we already have this specialization. */
18443 /* targ_ptr only has the innermost template args, so add the outer ones
18444 from tmpl, which could be either a partial instantiation or gen_tmpl (in
18445 the case of a non-dependent call within a template definition). */
18446 targ_ptr = (add_outermost_template_args
18448 targ_ptr));
18450 /* It would be nice to avoid hashing here and then again in tsubst_decl,
18451 but it doesn't seem to be on the hot path. */
18460 {
18462 {
18466 }
18468 }
18471 complain))
18474 /* We are building a FUNCTION_DECL, during which the access of its
18475 parameters and return types have to be checked. However this
18476 FUNCTION_DECL which is the desired context for access checking
18477 is not built yet. We solve this chicken-and-egg problem by
18478 deferring all checks until we have the FUNCTION_DECL. */
18481 /* Instantiation of the function happens in the context of the function
18482 template, not the context of the overload resolution we're doing. */
18484 /* If there are dependent arguments, e.g. because we're doing partial
18485 ordering, make sure processing_template_decl stays set. */
18489 {
18493 }
18499 {
18500 /* We need to determine if we're using a partial or explicit
18501 specialization now, because the type of the variable could be
18502 different. */
18508 {
18513 }
18514 }
18516 /* Substitute template parameters to obtain the specialization. */
18524 {
18527 }
18529 /* The DECL_TI_TEMPLATE should always be the immediate parent
18530 template, not the most general template. */
18534 /* Now we know the specialization, compute access previously
18535 deferred. Do no access control for inheriting constructors,
18536 as we already checked access for the inherited constructor. */
18539 {
18544 }
18547 /* If we've just instantiated the main entry point for a function,
18548 instantiate all the alternate entry points as well. We do this
18549 by cloning the instantiation of the main entry point, not by
18550 instantiating the template clones. */
18555 {
18557 {
18558 /* Remember to reinstantiate when we're out of SFINAE so the user
18559 can see the errors. */
18561 }
18563 }
18565 }
18567 /* Wrapper for instantiate_template_1. */
18569 tree
18571 {
18572 tree ret;
18577 }
18579 /* Instantiate the alias template TMPL with ARGS. Also push a template
18580 instantiation level, which instantiate_template doesn't do because
18581 functions and variables have sufficient context established by the
18582 callers. */
18584 static tree
18586 {
18593 {
18596 }
18598 args =
18606 /* We can't free this if a pending_template entry or last_error_tinst_level
18607 is pointing at it. */
18613 }
18615 /* PARM is a template parameter pack for FN. Returns true iff
18616 PARM is used in a deducible way in the argument list of FN. */
18618 static bool
18620 {
18623 {
18625 tree packs;
18631 {
18632 /* The template parameter pack is used in a function parameter
18633 pack. If this is the end of the parameter list, the
18634 template parameter pack is deducible. */
18637 else
18638 /* Otherwise, not. Well, it could be deduced from
18639 a non-pack parameter, but doing so would end up with
18640 a deduction mismatch, so don't bother. */
18642 }
18643 }
18644 /* The template parameter pack isn't used in any function parameter
18645 packs, but it might be used deeper, e.g. tuple<Args...>. */
18647 }
18649 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
18650 NARGS elements of the arguments that are being used when calling
18651 it. TARGS is a vector into which the deduced template arguments
18652 are placed.
18654 Returns either a FUNCTION_DECL for the matching specialization of FN or
18655 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
18656 true, diagnostics will be printed to explain why it failed.
18658 If FN is a conversion operator, or we are trying to produce a specific
18659 specialization, RETURN_TYPE is the return type desired.
18661 The EXPLICIT_TARGS are explicit template arguments provided via a
18662 template-id.
18664 The parameter STRICT is one of:
18666 DEDUCE_CALL:
18667 We are deducing arguments for a function call, as in
18668 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
18669 deducing arguments for a call to the result of a conversion
18670 function template, as in [over.call.object].
18672 DEDUCE_CONV:
18673 We are deducing arguments for a conversion function, as in
18674 [temp.deduct.conv].
18676 DEDUCE_EXACT:
18677 We are deducing arguments when doing an explicit instantiation
18678 as in [temp.explicit], when determining an explicit specialization
18679 as in [temp.expl.spec], or when taking the address of a function
18680 template, as in [temp.deduct.funcaddr]. */
18682 tree
18684 tree explicit_targs,
18685 tree targs,
18688 tree return_type,
18689 unification_kind_t strict,
18693 {
18694 tree parms;
18695 tree fntype;
18708 tree tinst;
18714 full_targs = (add_outermost_template_args
18716 targs));
18721 /* In C++0x, it's possible to have a function template whose type depends
18722 on itself recursively. This is most obvious with decltype, but can also
18723 occur with enumeration scope (c++/48969). So we need to catch infinite
18724 recursion and reject the substitution at deduction time; this function
18725 will return error_mark_node for any repeated substitution.
18727 This also catches excessive recursion such as when f<N> depends on
18728 f<N-1> across all integers, and returns error_mark_node for all the
18729 substitutions back up to the initial one.
18731 This is, of course, not reentrant. */
18741 {
18742 /* [temp.deduct]
18744 The specified template arguments must match the template
18745 parameters in kind (i.e., type, nontype, template), and there
18746 must not be more arguments than there are parameters;
18747 otherwise type deduction fails.
18749 Nontype arguments must match the types of the corresponding
18750 nontype template parameters, or must be convertible to the
18751 types of the corresponding nontype parameters as specified in
18752 _temp.arg.nontype_, otherwise type deduction fails.
18754 All references in the function type of the function template
18755 to the corresponding template parameters are replaced by the
18756 specified template argument values. If a substitution in a
18757 template parameter or in the function type of the function
18758 template results in an invalid type, type deduction fails. */
18769 explicit_targs);
18771 /* Adjust any explicit template arguments before entering the
18772 substitution context. */
18773 explicit_targs
18775 complain,
18781 /* Substitute the explicit args into the function type. This is
18782 necessary so that, for instance, explicitly declared function
18783 arguments can match null pointed constants. If we were given
18784 an incomplete set of explicit args, we must not do semantic
18785 processing during substitution as we could create partial
18786 instantiations. */
18788 {
18793 /* Dig out the actual parm. */
18796 {
18799 }
18801 {
18804 }
18807 /* No explicit argument for this template parameter. */
18811 {
18812 /* Mark the argument pack as "incomplete". We could
18813 still deduce more arguments during unification.
18814 We remove this mark in type_unification_real. */
18816 {
18820 }
18822 /* We have some incomplete argument packs. */
18824 }
18825 }
18829 {
18832 }
18835 /* Ignore any access checks; we'll see them again in
18836 instantiate_template and they might have the wrong
18837 access path at this point. */
18849 /* Place the explicitly specified arguments in TARGS. */
18853 }
18855 /* Never do unification on the 'this' parameter. */
18859 {
18860 /* We're deducing for a call to the result of a template conversion
18861 function. The parms we really want are in return_type. */
18865 }
18867 {
18876 }
18878 /* We allow incomplete unification without an error message here
18879 because the standard doesn't seem to explicitly prohibit it. Our
18880 callers must be ready to deal with unification failures in any
18881 event. */
18884 /* If we aren't explaining yet, push tinst context so we can see where
18885 any errors (e.g. from class instantiations triggered by instantiation
18886 of default template arguments) come from. If we are explaining, this
18887 context is redundant. */
18889 {
18892 }
18894 /* type_unification_real will pass back any access checks from default
18895 template argument substitution. */
18907 /* Now that we have bindings for all of the template arguments,
18908 ensure that the arguments deduced for the template template
18909 parameters have compatible template parameter lists. We cannot
18910 check this property before we have deduced all template
18911 arguments, because the template parameter types of a template
18912 template parameter might depend on prior template parameters
18913 deduced after the template template parameter. The following
18914 ill-formed example illustrates this issue:
18916 template<typename T, template<T> class C> void f(C<5>, T);
18918 template<int N> struct X {};
18920 void g() {
18921 f(X<5>(), 5l); // error: template argument deduction fails
18922 }
18924 The template parameter list of 'C' depends on the template type
18925 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
18926 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
18927 time that we deduce 'C'. */
18930 {
18933 }
18935 /* All is well so far. Now, check:
18937 [temp.deduct]
18939 When all template arguments have been deduced, all uses of
18940 template parameters in nondeduced contexts are replaced with
18941 the corresponding deduced argument values. If the
18942 substitution results in an invalid type, as described above,
18943 type deduction fails. */
18946 {
18949 }
18951 /* Also collect access checks from the instantiation. */
18964 /* Now perform any access checks encountered during substitution. */
18971 /* If we're looking for an exact match, check that what we got
18972 is indeed an exact match. It might not be if some template
18973 parameters are used in non-deduced contexts. But don't check
18974 for an exact match if we have dependent template arguments;
18975 in that case we're doing partial ordering, and we already know
18976 that we have two candidates that will provide the actual type. */
18978 {
18982 tree sarg
18988 {
18992 }
18993 }
18995 /* After doing deduction with the inherited constructor, actually return an
18996 instantiation of the inheriting constructor. */
19002 fail:
19005 {
19007 /* Reset once we're all the way out. */
19009 }
19011 /* We can't free this if a pending_template entry or last_error_tinst_level
19012 is pointing at it. */
19018 }
19020 /* Adjust types before performing type deduction, as described in
19021 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
19022 sections are symmetric. PARM is the type of a function parameter
19023 or the return type of the conversion function. ARG is the type of
19024 the argument passed to the call, or the type of the value
19025 initialized with the result of the conversion function.
19026 ARG_EXPR is the original argument expression, which may be null. */
19028 static int
19032 tree arg_expr)
19033 {
19037 {
19042 /* Swap PARM and ARG throughout the remainder of this
19043 function; the handling is precisely symmetric since PARM
19044 will initialize ARG rather than vice versa. */
19049 /* Core issue #873: Do the DR606 thing (see below) for these cases,
19050 too, but here handle it by stripping the reference from PARM
19051 rather than by adding it to ARG. */
19059 /* Nothing else to do in this case. */
19064 }
19067 {
19068 /* [temp.deduct.call]
19070 If P is not a reference type:
19072 --If A is an array type, the pointer type produced by the
19073 array-to-pointer standard conversion (_conv.array_) is
19074 used in place of A for type deduction; otherwise,
19076 --If A is a function type, the pointer type produced by
19077 the function-to-pointer standard conversion
19078 (_conv.func_) is used in place of A for type deduction;
19079 otherwise,
19081 --If A is a cv-qualified type, the top level
19082 cv-qualifiers of A's type are ignored for type
19083 deduction. */
19088 else
19090 }
19092 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
19093 reference to a cv-unqualified template parameter that does not represent a
19094 template parameter of a class template (during class template argument
19095 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
19096 an lvalue, the type "lvalue reference to A" is used in place of A for type
19097 deduction. */
19104 /* try_one_overload doesn't provide an arg_expr, but
19105 functions are always lvalues. */
19109 /* [temp.deduct.call]
19111 If P is a cv-qualified type, the top level cv-qualifiers
19112 of P's type are ignored for type deduction. If P is a
19113 reference type, the type referred to by P is used for
19114 type deduction. */
19117 {
19120 }
19122 /* DR 322. For conversion deduction, remove a reference type on parm
19123 too (which has been swapped into ARG). */
19128 }
19130 /* Subroutine of unify_one_argument. PARM is a function parameter of a
19131 template which does contain any deducible template parameters; check if
19132 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
19133 unify_one_argument. */
19135 static int
19138 {
19139 tree type;
19143 else
19150 {
19154 }
19156 {
19161 }
19165 else
19167 }
19171 /* Returns true iff the expression EXPR is one from which a template
19172 argument can be deduced. In other words, if it's an undecorated
19173 use of a template non-type parameter. */
19175 static bool
19177 {
19178 /* Strip implicit conversions. */
19182 }
19184 /* Returns true iff the array domain DOMAIN uses a template parameter in a
19185 deducible way; that is, if it has a max value of <PARM> - 1. */
19187 static bool
19189 {
19198 }
19200 /* Returns true iff the template arguments ARGS use a template parameter
19201 in a deducible way. */
19203 static bool
19205 {
19207 {
19212 else
19213 {
19220 else
19222 }
19225 }
19227 }
19229 /* Returns true iff TYPE contains any deducible references to template
19230 parameters, as per 14.8.2.5. */
19232 static bool
19234 {
19238 /* T
19239 cv-list T
19240 TT<T>
19241 TT<i>
19242 TT<> */
19247 /* T*
19248 T&
19249 T&& */
19253 /* T[integer-constant ]
19254 type [i] */
19259 /* T type ::*
19260 type T::*
19261 T T::*
19262 T (type ::*)()
19263 type (T::*)()
19264 type (type ::*)(T)
19265 type (T::*)(T)
19266 T (type ::*)(T)
19267 T (T::*)()
19268 T (T::*)(T) */
19271 || (uses_deducible_template_parms
19274 /* template-name <T> (where template-name refers to a class template)
19275 template-name <i> (where template-name refers to a class template) */
19282 /* type (T)
19283 T()
19284 T(T) */
19287 {
19296 }
19299 }
19301 /* Subroutine of type_unification_real and unify_pack_expansion to
19302 handle unification of a single P/A pair. Parameters are as
19303 for those functions. */
19305 static int
19309 {
19316 /* We can't deduce anything from this, but we might get all the
19317 template args from other function args. */
19320 /* Implicit conversions (Clause 4) will be performed on a function
19321 argument to convert it to the type of the corresponding function
19322 parameter if the parameter type contains no template-parameters that
19323 participate in template argument deduction. */
19326 /* For function parameters with no deducible template parameters,
19327 just return. We'll check non-dependent conversions later. */
19331 {
19333 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
19334 | UNIFY_ALLOW_MORE_CV_QUAL
19348 }
19350 /* We only do these transformations if this is the top-level
19351 parameter_type_list in a call or declaration matching; in other
19352 situations (nested function declarators, template argument lists) we
19353 won't be comparing a type to an expression, and we don't do any type
19354 adjustments. */
19356 {
19358 {
19361 {
19362 /* [temp.deduct.type] A template-argument can be
19363 deduced from a pointer to function or pointer
19364 to member function argument if the set of
19365 overloaded functions does not contain function
19366 templates and at most one of a set of
19367 overloaded functions provides a unique
19368 match. */
19372 /* If a unique match was not found, this is a
19373 non-deduced context, so we still succeed. */
19375 }
19381 }
19383 arg_strict |=
19385 }
19386 else
19391 /* For deduction from an init-list we need the actual list. */
19395 }
19397 /* for_each_template_parm callback that always returns 0. */
19399 static int
19401 {
19403 }
19405 /* for_each_template_parm any_fn callback to handle deduction of a template
19406 type argument from the type of an array bound. */
19408 static int
19410 {
19418 {
19424 }
19426 /* Keep walking. */
19428 }
19430 /* Try to deduce any not-yet-deduced template type arguments from the type of
19431 an array bound. This is handled separately from unify because 14.8.2.5 says
19432 "The type of a type parameter is only deduced from an array bound if it is
19433 not otherwise deduced." */
19435 static void
19437 {
19442 }
19444 /* Most parms like fn_type_unification.
19446 If SUBR is 1, we're being called recursively (to unify the
19447 arguments of a function or method parameter of a function
19448 template).
19450 CHECKS is a pointer to a vector of access checks encountered while
19451 substituting default template arguments. */
19453 static int
19455 tree full_targs,
19456 tree xparms,
19460 unification_kind_t strict,
19464 {
19469 tree parms;
19480 /* Reset the number of non-defaulted template arguments contained
19481 in TARGS. */
19484 again:
19492 {
19497 /* For a function parameter pack that occurs at the end of the
19498 parameter-declaration-list, the type A of each remaining
19499 argument of the call is compared with the type P of the
19500 declarator-id of the function parameter pack. */
19506 /* For a function parameter pack that does not occur at the
19507 end of the parameter-declaration-list, the type of the
19508 parameter pack is a non-deduced context. */
19515 explain_p))
19517 }
19522 {
19523 /* Unify the remaining arguments with the pack expansion type. */
19524 tree argvec;
19527 /* Allocate a TREE_VEC and copy in all of the arguments */
19532 /* Copy the parameter into parmvec. */
19538 /* Advance to the end of the list of parameters. */
19540 }
19542 /* Fail if we've reached the end of the parm list, and more args
19543 are present, and the parm list isn't variadic. */
19546 /* Fail if parms are left and they don't have default values and
19547 they aren't all deduced as empty packs (c++/57397). This is
19548 consistent with sufficient_parms_p. */
19551 {
19555 do
19556 {
19559 count++;
19561 }
19565 type_pack_p);
19566 }
19569 {
19570 tsubst_flags_t complain = (explain_p
19571 ? tf_warning_or_error
19576 {
19580 /* Clear the "incomplete" flags on all argument packs now so that
19581 substituting them into later default arguments works. */
19583 {
19586 }
19594 {
19599 }
19601 /* If this is an undeduced nontype parameter that depends on
19602 a type parameter, try another pass; its type may have been
19603 deduced from a later argument than the one from which
19604 this parameter can be deduced. */
19608 {
19611 }
19613 /* Core issue #226 (C++0x) [temp.deduct]:
19615 If a template argument has not been deduced, its
19616 default template argument, if any, is used.
19618 When we are in C++98 mode, TREE_PURPOSE will either
19619 be NULL_TREE or ERROR_MARK_NODE, so we do not need
19620 to explicitly check cxx_dialect here. */
19622 /* OK, there is a default argument. Wait until after the
19623 conversion check to do substitution. */
19626 /* If the type parameter is a parameter pack, then it will
19627 be deduced to an empty parameter pack. */
19629 {
19630 tree arg;
19633 {
19636 }
19637 else
19644 }
19647 }
19649 /* DR 1391: All parameters have args, now check non-dependent parms for
19650 convertibility. */
19654 {
19660 /* For a function parameter pack that occurs at the end of the
19661 parameter-declaration-list, the type A of each remaining
19662 argument of the call is compared with the type P of the
19663 declarator-id of the function parameter pack. */
19669 /* For a function parameter pack that does not occur at the
19670 end of the parameter-declaration-list, the type of the
19671 parameter pack is a non-deduced context. */
19680 explain_p))
19682 }
19684 /* Now substitute into the default template arguments. */
19686 {
19710 else
19718 {
19720 /* The position of the first default template argument,
19721 is also the number of non-defaulted arguments in TARGS.
19722 Record that. */
19725 }
19726 }
19730 }
19736 }
19738 /* Subroutine of type_unification_real. Args are like the variables
19739 at the call site. ARG is an overloaded function (or template-id);
19740 we try deducing template args from each of the overloads, and if
19741 only one succeeds, we go with that. Modifies TARGS and returns
19742 true on success. */
19744 static bool
19746 tree targs,
19747 tree parm,
19748 tree arg,
19749 unification_kind_t strict,
19752 {
19759 {
19762 }
19763 else
19767 /* Handle `&x' where `x' is some static or non-static member
19768 function name. */
19774 /* Strip baselink information. */
19779 {
19780 /* If we got some explicit template args, we need to plug them into
19781 the affected templates before we try to unify, in case the
19782 explicit args will completely resolve the templates in question. */
19789 {
19802 {
19807 {
19810 }
19811 }
19814 }
19815 /* If no templates (or more than one) are fully resolved by the
19816 explicit arguments, this template-id is a non-deduced context; it
19817 could still be OK if we deduce all template arguments for the
19818 enclosing call through other arguments. */
19821 }
19824 /* If ARG is, for example, "(0, &f)" then its type will be unknown
19825 -- but the deduction does not succeed because the expression is
19826 not just the function on its own. */
19828 else
19830 {
19835 {
19838 }
19839 }
19841 /* [temp.deduct.type] A template-argument can be deduced from a pointer
19842 to function or pointer to member function argument if the set of
19843 overloaded functions does not contain function templates and at most
19844 one of a set of overloaded functions provides a unique match.
19846 So if we found multiple possibilities, we return success but don't
19847 deduce anything. */
19850 {
19854 {
19859 /* Don't forget explicit template arguments in a pack. */
19863 }
19864 }
19869 }
19871 /* Core DR 115: In contexts where deduction is done and fails, or in
19872 contexts where deduction is not done, if a template argument list is
19873 specified and it, along with any default template arguments, identifies
19874 a single function template specialization, then the template-id is an
19875 lvalue for the function template specialization. */
19877 tree
19879 {
19892 {
19895 }
19897 {
19900 }
19902 {
19905 }
19908 {
19912 /* If we got some explicit template args, we need to plug them into
19913 the affected templates before we try to unify, in case the
19914 explicit args will completely resolve the templates in question. */
19922 {
19935 {
19938 {
19941 }
19943 {
19946 }
19947 }
19948 }
19950 {
19958 {
19959 tree base
19962 }
19966 }
19968 /* There were no good options and at least one bad one, so let the
19969 user know what the problem is. */
19971 }
19973 }
19975 /* Subroutine of resolve_overloaded_unification; does deduction for a single
19976 overload. Fills TARGS with any deduced arguments, or error_mark_node if
19977 different overloads deduce different arguments for a given parm.
19978 ADDR_P is true if the expression for which deduction is being
19979 performed was of the form "& fn" rather than simply "fn".
19981 Returns 1 on success. */
19983 static int
19985 tree orig_targs,
19986 tree targs,
19987 tree parm,
19988 tree arg,
19989 unification_kind_t strict,
19993 {
19995 tree tempargs;
20001 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20002 to function or pointer to member function argument if the set of
20003 overloaded functions does not contain function templates and at most
20004 one of a set of overloaded functions provides a unique match.
20006 So if this is a template, just return success. */
20018 /* We don't copy orig_targs for this because if we have already deduced
20019 some template args from previous args, unify would complain when we
20020 try to deduce a template parameter for the same argument, even though
20021 there isn't really a conflict. */
20028 /* First make sure we didn't deduce anything that conflicts with
20029 explicitly specified args. */
20031 {
20038 /* Since we're unifying against ourselves, we will fill in
20039 template args used in the function parm list with our own
20040 template parms. Discard them. */
20043 {
20044 /* Check that the argument at each index of the deduced argument pack
20045 is equivalent to the corresponding explicitly specified argument.
20046 We may have deduced more arguments than were explicitly specified,
20047 and that's OK. */
20049 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
20050 that's wrong if we deduce the same argument pack from multiple
20051 function arguments: it's only incomplete the first time. */
20064 }
20067 }
20070 {
20075 }
20078 }
20080 /* PARM is a template class (perhaps with unbound template
20081 parameters). ARG is a fully instantiated type. If ARG can be
20082 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
20083 TARGS are as for unify. */
20085 static tree
20088 {
20089 tree copy_of_targs;
20099 /* We need to make a new template argument vector for the call to
20100 unify. If we used TARGS, we'd clutter it up with the result of
20101 the attempted unification, even if this class didn't work out.
20102 We also don't want to commit ourselves to all the unifications
20103 we've already done, since unification is supposed to be done on
20104 an argument-by-argument basis. In other words, consider the
20105 following pathological case:
20107 template <int I, int J, int K>
20108 struct S {};
20110 template <int I, int J>
20111 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
20113 template <int I, int J, int K>
20114 void f(S<I, J, K>, S<I, I, I>);
20116 void g() {
20117 S<0, 0, 0> s0;
20118 S<0, 1, 2> s2;
20120 f(s0, s2);
20121 }
20123 Now, by the time we consider the unification involving `s2', we
20124 already know that we must have `f<0, 0, 0>'. But, even though
20125 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
20126 because there are two ways to unify base classes of S<0, 1, 2>
20127 with S<I, I, I>. If we kept the already deduced knowledge, we
20128 would reject the possibility I=1. */
20132 {
20136 }
20138 /* If unification failed, we're done. */
20144 }
20146 /* Given a template type PARM and a class type ARG, find the unique
20147 base type in ARG that is an instance of PARM. We do not examine
20148 ARG itself; only its base-classes. If there is not exactly one
20149 appropriate base class, return NULL_TREE. PARM may be the type of
20150 a partial specialization, as well as a plain template type. Used
20151 by unify. */
20153 static enum template_base_result
20156 {
20158 tree binfo;
20164 {
20165 /* The type could not be completed. */
20168 }
20170 /* Walk in inheritance graph order. The search order is not
20171 important, and this avoids multiple walks of virtual bases. */
20173 {
20178 {
20179 /* If there is more than one satisfactory baseclass, then:
20181 [temp.deduct.call]
20183 If they yield more than one possible deduced A, the type
20184 deduction fails.
20186 applies. */
20188 {
20191 }
20194 }
20195 }
20199 }
20201 /* Returns the level of DECL, which declares a template parameter. */
20203 static int
20205 {
20207 {
20217 }
20219 }
20221 /* Decide whether ARG can be unified with PARM, considering only the
20222 cv-qualifiers of each type, given STRICT as documented for unify.
20223 Returns nonzero iff the unification is OK on that basis. */
20225 static int
20227 {
20233 {
20234 /* Although a CVR qualifier is ignored when being applied to a
20235 substituted template parameter ([8.3.2]/1 for example), that
20236 does not allow us to unify "const T" with "int&" because both
20237 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
20238 It is ok when we're allowing additional CV qualifiers
20239 at the outer level [14.8.2.1]/3,1st bullet. */
20249 }
20260 }
20262 /* Determines the LEVEL and INDEX for the template parameter PARM. */
20263 void
20265 {
20269 {
20272 }
20273 else
20274 {
20277 }
20278 }
20280 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
20281 do { \
20282 if (unify (TP, TA, P, A, S, EP)) \
20283 return 1; \
20284 } while (0)
20286 /* Unifies the remaining arguments in PACKED_ARGS with the pack
20287 expansion at the end of PACKED_PARMS. Returns 0 if the type
20288 deduction succeeds, 1 otherwise. STRICT is the same as in
20289 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
20290 function call argument list. We'll need to adjust the arguments to make them
20291 types. SUBR tells us if this is from a recursive call to
20292 type_unification_real, or for comparing two template argument
20293 lists. */
20295 static int
20299 {
20300 tree parm
20306 /* Add in any args remembered from an earlier partial instantiation. */
20313 /* Determine the parameter packs we will be deducing from the
20314 pattern, and record their current deductions. */
20317 {
20321 /* Determine the index and level of this parameter pack. */
20324 /* Keep track of the parameter packs and their corresponding
20325 argument packs. */
20328 }
20330 /* Loop through all of the arguments that have not yet been
20331 unified and unify each with the pattern. */
20333 {
20334 tree parm;
20338 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
20339 or the element of its argument pack at the current index if
20340 this argument was explicitly specified. */
20342 {
20351 {
20354 }
20356 }
20358 /* If we had explicit template arguments, substitute them into the
20359 pattern before deduction. */
20361 {
20362 /* Some arguments might still be unspecified or dependent. */
20370 NULL_TREE);
20375 }
20376 else
20379 /* Unify the pattern with the current argument. */
20381 explain_p))
20384 /* For each parameter pack, collect the deduced value. */
20386 {
20392 }
20393 }
20395 /* Verify that the results of unification with the parameter packs
20396 produce results consistent with what we've seen before, and make
20397 the deduced argument packs available. */
20399 {
20406 /* By default keep the original deduced argument pack.
20407 If necessary, more specific code is going to update the
20408 resulting deduced argument later down in this function. */
20412 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
20413 actually deduce anything. */
20421 {
20422 /* If we had fewer function args than explicit template args,
20423 just use the explicits. */
20428 }
20431 {
20432 tree result;
20433 /* Build the deduced *_ARGUMENT_PACK. */
20435 {
20438 }
20439 else
20444 /* Note the deduced argument packs for this parameter
20445 pack. */
20447 }
20451 {
20452 /* We only had the explicitly-provided arguments before, but
20453 now we have a complete set of arguments. */
20459 }
20460 else
20461 {
20467 /* Inconsistent unification of this parameter pack. */
20469 bad_old_arg,
20470 bad_new_arg);
20471 }
20472 }
20475 }
20477 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
20478 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
20479 parameters and return value are as for unify. */
20481 static int
20485 {
20486 tree parm_max;
20487 tree arg_max;
20491 /* Our representation of array types uses "N - 1" as the
20492 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
20493 not an integer constant. We cannot unify arbitrarily
20494 complex expressions, so we eliminate the MINUS_EXPRs
20495 here. */
20499 {
20502 }
20506 {
20507 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
20508 trying to unify the type of a variable with the type
20509 of a template parameter. For example:
20511 template <unsigned int N>
20512 void f (char (&) [N]);
20513 int g();
20514 void h(int i) {
20515 char a[g(i)];
20516 f(a);
20517 }
20519 Here, the type of the ARG will be "int [g(i)]", and
20520 may be a SAVE_EXPR, etc. */
20524 }
20526 /* If only one of the bounds used a MINUS_EXPR, compensate
20527 by adding one to the other bound. */
20530 integer_type_node,
20531 parm_max,
20532 integer_one_node);
20535 integer_type_node,
20536 arg_max,
20537 integer_one_node);
20541 }
20543 /* Returns whether T, a P or A in unify, is a type, template or expression. */
20547 static pa_kind_t
20549 {
20558 else
20560 }
20562 /* Deduce the value of template parameters. TPARMS is the (innermost)
20563 set of template parameters to a template. TARGS is the bindings
20564 for those template parameters, as determined thus far; TARGS may
20565 include template arguments for outer levels of template parameters
20566 as well. PARM is a parameter to a template function, or a
20567 subcomponent of that parameter; ARG is the corresponding argument.
20568 This function attempts to match PARM with ARG in a manner
20569 consistent with the existing assignments in TARGS. If more values
20570 are deduced, then TARGS is updated.
20572 Returns 0 if the type deduction succeeds, 1 otherwise. The
20573 parameter STRICT is a bitwise or of the following flags:
20575 UNIFY_ALLOW_NONE:
20576 Require an exact match between PARM and ARG.
20577 UNIFY_ALLOW_MORE_CV_QUAL:
20578 Allow the deduced ARG to be more cv-qualified (by qualification
20579 conversion) than ARG.
20580 UNIFY_ALLOW_LESS_CV_QUAL:
20581 Allow the deduced ARG to be less cv-qualified than ARG.
20582 UNIFY_ALLOW_DERIVED:
20583 Allow the deduced ARG to be a template base class of ARG,
20584 or a pointer to a template base class of the type pointed to by
20585 ARG.
20586 UNIFY_ALLOW_INTEGER:
20587 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
20588 case for more information.
20589 UNIFY_ALLOW_OUTER_LEVEL:
20590 This is the outermost level of a deduction. Used to determine validity
20591 of qualification conversions. A valid qualification conversion must
20592 have const qualified pointers leading up to the inner type which
20593 requires additional CV quals, except at the outer level, where const
20594 is not required [conv.qual]. It would be normal to set this flag in
20595 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
20596 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
20597 This is the outermost level of a deduction, and PARM can be more CV
20598 qualified at this point.
20599 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
20600 This is the outermost level of a deduction, and PARM can be less CV
20601 qualified at this point. */
20603 static int
20606 {
20608 tree targ;
20609 tree tparm;
20611 tsubst_flags_t complain = (explain_p
20612 ? tf_warning_or_error
20615 /* I don't think this will do the right thing with respect to types.
20616 But the only case I've seen it in so far has been array bounds, where
20617 signedness is the only information lost, and I think that will be
20618 okay. */
20626 /* We can't deduce anything from this, but we might get all the
20627 template args from other function args. */
20633 /* If PARM uses template parameters, then we can't bail out here,
20634 even if ARG == PARM, since we won't record unifications for the
20635 template parameters. We might need them if we're trying to
20636 figure out which of two things is more specialized. */
20640 /* Handle init lists early, so the rest of the function can assume
20641 we're dealing with a type. */
20643 {
20648 /* Replace T with std::initializer_list<T> for deduction. */
20655 /* We can only deduce from an initializer list argument if the
20656 parameter is std::initializer_list or an array; otherwise this
20657 is a non-deduced context. */
20662 else
20663 {
20665 /* Deduction is defined in terms of a single type, so just punt
20666 on the (bizarre) std::initializer_list<T...>. */
20669 }
20672 {
20679 {
20683 /* It should only be possible to get here for a call. */
20685 elt_strict |= maybe_adjust_types_for_deduction
20688 }
20691 explain_p);
20692 }
20696 {
20697 /* Also deduce from the length of the initializer list. */
20704 }
20706 /* If the std::initializer_list<T> deduction worked, replace the
20707 deduced A with std::initializer_list<A>. */
20709 {
20714 }
20716 }
20718 /* If parm and arg aren't the same kind of thing (template, type, or
20719 expression), fail early. */
20723 /* Immediately reject some pairs that won't unify because of
20724 cv-qualification mismatches. */
20727 /* It is the elements of the array which hold the cv quals of an array
20728 type, and the elements might be template type parms. We'll check
20729 when we recurse. */
20731 /* We check the cv-qualifiers when unifying with template type
20732 parameters below. We want to allow ARG `const T' to unify with
20733 PARM `T' for example, when computing which of two templates
20734 is more specialized, for example. */
20748 {
20752 /* In a type which contains a nested-name-specifier, template
20753 argument values cannot be deduced for template parameters used
20754 within the nested-name-specifier. */
20766 /* The PARM is not one we're trying to unify. Just check
20767 to see if it matches ARG. */
20768 {
20773 else
20775 }
20782 /* Check for mixed types and values. */
20790 {
20793 {
20794 /* First try to match ARG directly. */
20796 explain_p);
20798 {
20799 /* Otherwise, look for a suitable base of ARG, as below. */
20806 }
20807 }
20808 /* ARG must be constructed from a template class or a template
20809 template parameter. */
20814 /* Deduce arguments T, i from TT<T> or TT<i>. */
20820 /* Fall through to deduce template name. */
20821 }
20825 {
20826 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
20828 /* Simple cases: Value already set, does match or doesn't. */
20833 }
20834 else
20835 {
20836 /* If PARM is `const T' and ARG is only `int', we don't have
20837 a match unless we are allowing additional qualification.
20838 If ARG is `const int' and PARM is just `T' that's OK;
20839 that binds `const int' to `T'. */
20844 /* Consider the case where ARG is `const volatile int' and
20845 PARM is `const T'. Then, T should be `volatile int'. */
20846 arg = cp_build_qualified_type_real
20851 /* Simple cases: Value already set, does match or doesn't. */
20857 /* Make sure that ARG is not a variable-sized array. (Note
20858 that were talking about variable-sized arrays (like
20859 `int[n]'), rather than arrays of unknown size (like
20860 `int[]').) We'll get very confused by such a type since
20861 the bound of the array is not constant, and therefore
20862 not mangleable. Besides, such types are not allowed in
20863 ISO C++, so we can do as we please here. We do allow
20864 them for 'auto' deduction, since that isn't ABI-exposed. */
20868 /* Strip typedefs as in convert_template_argument. */
20870 }
20872 /* If ARG is a parameter pack or an expansion, we cannot unify
20873 against it unless PARM is also a parameter pack. */
20878 /* If the argument deduction results is a METHOD_TYPE,
20879 then there is a problem.
20880 METHOD_TYPE doesn't map to any real C++ type the result of
20881 the deduction can not be of that type. */
20895 {
20896 /* The PARM is not one we're trying to unify. Just check
20897 to see if it matches ARG. */
20903 }
20909 {
20914 }
20916 /* [temp.deduct.type] If, in the declaration of a function template
20917 with a non-type template-parameter, the non-type
20918 template-parameter is used in an expression in the function
20919 parameter-list and, if the corresponding template-argument is
20920 deduced, the template-argument type shall match the type of the
20921 template-parameter exactly, except that a template-argument
20922 deduced from an array bound may be of any integral type.
20923 The non-type parameter might use already deduced type parameters. */
20926 {
20930 }
20933 /* Template-parameter dependent expression. Just accept it for now.
20934 It will later be processed in convert_template_argument. */
20935 ;
20941 /* Convert the ARG to the type of PARM; the deduced non-type
20942 template argument must exactly match the types of the
20943 corresponding parameter. */
20946 {
20947 /* We haven't deduced the type of this parameter yet. */
20949 /* We deduce from array bounds in try_array_deduction. */
20951 {
20952 /* Deduce it from the non-type argument. */
20957 }
20958 else
20959 /* Try again later. */
20961 }
20962 else
20965 /* If ARG is a parameter pack or an expansion, we cannot unify
20966 against it unless PARM is also a parameter pack. */
20971 {
20974 }
20979 {
20980 /* A pointer-to-member constant can be unified only with
20981 another constant. */
20985 /* Just unify the class member. It would be useless (and possibly
20986 wrong, depending on the strict flags) to unify also
20987 PTRMEM_CST_CLASS, because we want to be sure that both parm and
20988 arg refer to the same variable, even if through different
20989 classes. For instance:
20991 struct A { int x; };
20992 struct B : A { };
20994 Unification of &A::x and &B::x must succeed. */
20997 }
21000 {
21004 /* [temp.deduct.call]
21006 A can be another pointer or pointer to member type that can
21007 be converted to the deduced A via a qualification
21008 conversion (_conv.qual_).
21010 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
21011 This will allow for additional cv-qualification of the
21012 pointed-to types if appropriate. */
21015 /* The derived-to-base conversion only persists through one
21016 level of pointers. */
21021 }
21053 /* We have already checked cv-qualification at the top of the
21054 function. */
21058 /* As far as unification is concerned, this wins. Later checks
21059 will invalidate it if necessary. */
21062 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
21063 /* Type INTEGER_CST can come from ordinary constant template args. */
21075 {
21085 /* Check for pack expansions in the parameters. */
21087 {
21089 {
21091 /* We can unify against something with a trailing
21092 parameter pack. */
21094 else
21095 /* [temp.deduct.type]/9: If the template argument list of
21096 P contains a pack expansion that is not the last
21097 template argument, the entire template argument list
21098 is a non-deduced context. */
21100 }
21101 }
21103 /* If we don't have enough arguments to satisfy the parameters
21104 (not counting the pack expression at the end), or we have
21105 too many arguments for a parameter list that doesn't end in
21106 a pack expression, we can't unify. */
21112 /* Unify all of the parameters that precede the (optional)
21113 pack expression. */
21115 {
21120 }
21123 DEDUCE_EXACT,
21126 }
21134 {
21142 }
21147 {
21151 {
21152 /* First, we try to unify the PARM and ARG directly. */
21157 {
21158 /* Fallback to the special case allowed in
21159 [temp.deduct.call]:
21161 If P is a class, and P has the form
21162 template-id, then A can be a derived class of
21163 the deduced A. Likewise, if P is a pointer to
21164 a class of the form template-id, A can be a
21165 pointer to a derived class pointed to by the
21166 deduced A. */
21172 {
21173 /* Don't give the derived diagnostic if we're
21174 already dealing with the same template. */
21175 bool same_template
21181 }
21182 }
21183 }
21187 /* Perhaps PARM is something like S<U> and ARG is S<int>.
21188 Then, we should unify `int' and `U'. */
21190 else
21191 /* There's no chance of unification succeeding. */
21196 }
21203 {
21206 tree a;
21212 /* CV qualifications for methods can never be deduced, they must
21213 match exactly. We need to check them explicitly here,
21214 because type_unification_real treats them as any other
21215 cv-qualified parameter. */
21217 && (!check_cv_quals_for_unify
21245 {
21257 }
21260 }
21263 /* Unify a pointer to member with a pointer to member function, which
21264 deduces the type of the member as a function type. */
21266 {
21267 /* Check top-level cv qualifiers */
21275 /* Determine the type of the function we are unifying against. */
21279 }
21298 /* Matched cases are handled by the ARG == PARM test above. */
21302 /* We might get a variable as a non-type template argument in parm if the
21303 corresponding parameter is type-dependent. Make any necessary
21304 adjustments based on whether arg is a reference. */
21308 {
21313 }
21314 /* Now use the normal expression code to check whether they match. */
21325 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
21326 or UNDERLYING_TYPE nodes. */
21330 /* Unification fails if we hit an error node. */
21335 {
21345 }
21346 /* FALLTHRU */
21349 /* An unresolved overload is a nondeduced context. */
21353 expr:
21354 /* We must be looking at an expression. This can happen with
21355 something like:
21357 template <int I>
21358 void foo(S<I>, S<I + 2>);
21360 This is a "nondeduced context":
21362 [deduct.type]
21364 The nondeduced contexts are:
21366 --A type that is a template-id in which one or more of
21367 the template-arguments is an expression that references
21368 a template-parameter.
21370 In these cases, we assume deduction succeeded, but don't
21371 actually infer any unifications. */
21376 else
21378 }
21379 }
21380 #undef RECUR_AND_CHECK_FAILURE
21381 \f
21382 /* Note that DECL can be defined in this translation unit, if
21383 required. */
21385 static void
21387 {
21388 tree clone;
21392 }
21394 /* Called if RESULT is explicitly instantiated, or is a member of an
21395 explicitly instantiated class. */
21397 void
21399 {
21402 /* If this entity has already been written out, it's too late to
21403 make any modifications. */
21407 /* For anonymous namespace we don't need to do anything. */
21409 {
21412 }
21415 /* The TREE_PUBLIC flag for function declarations will have been
21416 set correctly by tsubst. */
21419 /* This might have been set by an earlier implicit instantiation. */
21424 else
21425 {
21428 /* Always make artificials weak. */
21431 /* For WIN32 we also want to put explicit instantiations in
21432 linkonce sections. */
21435 }
21437 /* If EXTERN_P, then this function will not be emitted -- unless
21438 followed by an explicit instantiation, at which point its linkage
21439 will be adjusted. If !EXTERN_P, then this function will be
21440 emitted here. In neither circumstance do we want
21441 import_export_decl to adjust the linkage. */
21443 }
21445 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
21446 important template arguments. If any are missing, we check whether
21447 they're important by using error_mark_node for substituting into any
21448 args that were used for partial ordering (the ones between ARGS and END)
21449 and seeing if it bubbles up. */
21451 static bool
21453 {
21458 {
21461 }
21463 {
21467 }
21469 }
21471 /* Given two function templates PAT1 and PAT2, return:
21473 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
21474 -1 if PAT2 is more specialized than PAT1.
21475 0 if neither is more specialized.
21477 LEN indicates the number of parameters we should consider
21478 (defaulted parameters should not be considered).
21480 The 1998 std underspecified function template partial ordering, and
21481 DR214 addresses the issue. We take pairs of arguments, one from
21482 each of the templates, and deduce them against each other. One of
21483 the templates will be more specialized if all the *other*
21484 template's arguments deduce against its arguments and at least one
21485 of its arguments *does* *not* deduce against the other template's
21486 corresponding argument. Deduction is done as for class templates.
21487 The arguments used in deduction have reference and top level cv
21488 qualifiers removed. Iff both arguments were originally reference
21489 types *and* deduction succeeds in both directions, an lvalue reference
21490 wins against an rvalue reference and otherwise the template
21491 with the more cv-qualified argument wins for that pairing (if
21492 neither is more cv-qualified, they both are equal). Unlike regular
21493 deduction, after all the arguments have been deduced in this way,
21494 we do *not* verify the deduced template argument values can be
21495 substituted into non-deduced contexts.
21497 The logic can be a bit confusing here, because we look at deduce1 and
21498 targs1 to see if pat2 is at least as specialized, and vice versa; if we
21499 can find template arguments for pat1 to make arg1 look like arg2, that
21500 means that arg2 is at least as specialized as arg1. */
21502 int
21504 {
21517 /* Remove the this parameter from non-static member functions. If
21518 one is a non-static member function and the other is not a static
21519 member function, remove the first parameter from that function
21520 also. This situation occurs for operator functions where we
21521 locate both a member function (with this pointer) and non-member
21522 operator (with explicit first operand). */
21524 {
21529 }
21531 {
21534 {
21535 len--;
21537 }
21538 }
21540 /* If only one is a conversion operator, they are unordered. */
21544 /* Consider the return type for a conversion function */
21546 {
21549 len++;
21550 }
21552 processing_template_decl++;
21558 /* Stop when an ellipsis is seen. */
21560 {
21571 {
21572 /* When both arguments are pack expansions, we need only
21573 unify the patterns themselves. */
21577 /* This is the last comparison we need to do. */
21579 }
21581 /* DR 1847: If a particular P contains no template-parameters that
21582 participate in template argument deduction, that P is not used to
21583 determine the ordering. */
21589 {
21593 }
21596 {
21600 }
21606 {
21612 /* Setup the parameter vector, which contains only ARG1. */
21615 /* Setup the argument vector, which contains the remaining
21616 arguments. */
21625 /* We cannot deduce in the other direction, because ARG1 is
21626 a pack expansion but ARG2 is not. */
21628 }
21630 {
21636 /* Setup the parameter vector, which contains only ARG1. */
21639 /* Setup the argument vector, which contains the remaining
21640 arguments. */
21649 /* We cannot deduce in the other direction, because ARG2 is
21650 a pack expansion but ARG1 is not.*/
21652 }
21654 else
21655 {
21656 /* The normal case, where neither argument is a pack
21657 expansion. */
21664 }
21666 /* If we couldn't deduce arguments for tparms1 to make arg1 match
21667 arg2, then arg2 is not as specialized as arg1. */
21673 /* "If, for a given type, deduction succeeds in both directions
21674 (i.e., the types are identical after the transformations above)
21675 and both P and A were reference types (before being replaced with
21676 the type referred to above):
21677 - if the type from the argument template was an lvalue reference and
21678 the type from the parameter template was not, the argument type is
21679 considered to be more specialized than the other; otherwise,
21680 - if the type from the argument template is more cv-qualified
21681 than the type from the parameter template (as described above),
21682 the argument type is considered to be more specialized than the other;
21683 otherwise,
21684 - neither type is more specialized than the other." */
21687 {
21689 {
21692 else
21694 }
21696 {
21701 }
21702 }
21705 /* We've failed to deduce something in either direction.
21706 These must be unordered. */
21709 next:
21713 /* We have already processed all of the arguments in our
21714 handing of the pack expansion type. */
21719 }
21721 /* "In most cases, all template parameters must have values in order for
21722 deduction to succeed, but for partial ordering purposes a template
21723 parameter may remain without a value provided it is not used in the
21724 types being used for partial ordering."
21726 Thus, if we are missing any of the targs1 we need to substitute into
21727 origs1, then pat2 is not as specialized as pat1. This can happen when
21728 there is a nondeduced context. */
21734 processing_template_decl--;
21736 /* If both deductions succeed, the partial ordering selects the more
21737 constrained template. */
21739 {
21744 }
21746 /* All things being equal, if the next argument is a pack expansion
21747 for one function but not for the other, prefer the
21748 non-variadic function. FIXME this is bogus; see c++/41958. */
21752 {
21755 }
21761 else
21763 }
21765 /* Determine which of two partial specializations of TMPL is more
21766 specialized.
21768 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
21769 to the first partial specialization. The TREE_PURPOSE is the
21770 innermost set of template parameters for the partial
21771 specialization. PAT2 is similar, but for the second template.
21773 Return 1 if the first partial specialization is more specialized;
21774 -1 if the second is more specialized; 0 if neither is more
21775 specialized.
21777 See [temp.class.order] for information about determining which of
21778 two templates is more specialized. */
21780 static int
21782 {
21783 tree targs;
21792 /* Just like what happens for functions, if we are ordering between
21793 different template specializations, we may encounter dependent
21794 types in the arguments, and we need our dependency check functions
21795 to behave correctly. */
21799 {
21802 }
21806 {
21809 }
21812 /* If both deductions succeed, the partial ordering selects the more
21813 constrained template. */
21817 /* In the case of a tie where at least one of the templates
21818 has a parameter pack at the end, the template with the most
21819 non-packed parameters wins. */
21821 && any_deductions
21824 {
21830 /* We don't count the pack expansion at the end. */
21840 }
21843 }
21845 /* Return the template arguments that will produce the function signature
21846 DECL from the function template FN, with the explicit template
21847 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
21848 also match. Return NULL_TREE if no satisfactory arguments could be
21849 found. */
21851 static tree
21853 {
21857 tree decl_arg_types;
21860 tree arg;
21864 /* Never do unification on the 'this' parameter. */
21885 }
21887 /* Return the innermost template arguments that, when applied to a partial
21888 specialization SPEC_TMPL of TMPL, yield the ARGS.
21890 For example, suppose we have:
21892 template <class T, class U> struct S {};
21893 template <class T> struct S<T*, int> {};
21895 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
21896 partial specialization and the ARGS will be {double*, int}. The resulting
21897 vector will be {double}, indicating that `T' is bound to `double'. */
21899 static tree
21901 {
21903 tree spec_args
21906 tree deduced_args;
21907 tree innermost_deduced_args;
21911 {
21915 innermost_deduced_args);
21916 }
21917 else
21921 again:
21930 {
21932 {
21938 }
21940 }
21944 {
21947 }
21949 /* Verify that nondeduced template arguments agree with the type
21950 obtained from argument deduction.
21952 For example:
21954 struct A { typedef int X; };
21955 template <class T, class U> struct C {};
21956 template <class T> struct C<T, typename T::X> {};
21958 Then with the instantiation `C<A, int>', we can deduce that
21959 `T' is `A' but unify () does not check whether `typename T::X'
21960 is `int'. */
21971 /* We only need to check the innermost arguments; the other
21972 arguments will always agree. */
21977 /* Now that we have bindings for all of the template arguments,
21978 ensure that the arguments deduced for the template template
21979 parameters have compatible template parameter lists. See the use
21980 of template_template_parm_bindings_ok_p in fn_type_unification
21981 for more information. */
21986 }
21988 // Compare two function templates T1 and T2 by deducing bindings
21989 // from one against the other. If both deductions succeed, compare
21990 // constraints to see which is more constrained.
21991 static int
21993 {
21998 {
22001 }
22004 {
22007 }
22009 // If both deductions succeed, then one may be more constrained.
22014 }
22016 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
22017 Return the TREE_LIST node with the most specialized template, if
22018 any. If there is no most specialized template, the error_mark_node
22019 is returned.
22021 Note that this function does not look at, or modify, the
22022 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
22023 returned is one of the elements of INSTANTIATIONS, callers may
22024 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
22025 and retrieve it from the value returned. */
22027 tree
22029 {
22036 {
22042 {
22043 /* Equally specialized, move to next function. If there
22044 is no next function, nothing's most specialized. */
22049 }
22050 }
22053 /* Now verify that champ is better than everything earlier in the
22054 instantiation list. */
22057 {
22060 }
22061 }
22063 processing_template_decl--;
22069 }
22071 /* If DECL is a specialization of some template, return the most
22072 general such template. Otherwise, returns NULL_TREE.
22074 For example, given:
22076 template <class T> struct S { template <class U> void f(U); };
22078 if TMPL is `template <class U> void S<int>::f(U)' this will return
22079 the full template. This function will not trace past partial
22080 specializations, however. For example, given in addition:
22082 template <class T> struct S<T*> { template <class U> void f(U); };
22084 if TMPL is `template <class U> void S<int*>::f(U)' this will return
22085 `template <class T> template <class U> S<T*>::f(U)'. */
22087 tree
22089 {
22091 {
22094 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
22095 template friend, or a FIELD_DECL for a capture pack. */
22098 }
22100 /* Look for more and more general templates. */
22102 {
22103 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
22104 (See cp-tree.h for details.) */
22113 /* Stop if we run into an explicitly specialized class template. */
22120 }
22123 }
22125 /* Return the most specialized of the template partial specializations
22126 which can produce TARGET, a specialization of some class or variable
22127 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
22128 a TEMPLATE_DECL node corresponding to the partial specialization, while
22129 the TREE_PURPOSE is the set of template arguments that must be
22130 substituted into the template pattern in order to generate TARGET.
22132 If the choice of partial specialization is ambiguous, a diagnostic
22133 is issued, and the error_mark_node is returned. If there are no
22134 partial specializations matching TARGET, then NULL_TREE is
22135 returned, indicating that the primary template should be used. */
22137 static tree
22139 {
22141 tree t;
22142 tree champ;
22149 {
22153 }
22155 {
22158 }
22160 {
22164 }
22165 else
22170 /* For determining which partial specialization to use, only the
22171 innermost args are interesting. */
22173 {
22176 }
22179 {
22180 tree spec_args;
22184 {
22185 /* Substitute in the template args from the enclosing class. */
22189 }
22196 {
22200 /* Keep the candidate only if the constraints are satisfied,
22201 or if we're not compiling with concepts. */
22204 {
22207 }
22208 }
22209 }
22219 {
22222 ;
22223 else
22224 {
22226 {
22229 {
22232 }
22233 }
22235 }
22236 }
22240 {
22243 {
22246 }
22247 }
22250 {
22257 else
22261 {
22266 }
22269 }
22272 }
22274 /* Explicitly instantiate DECL. */
22276 void
22278 {
22283 /* An error occurred, for which grokdeclarator has already issued
22284 an appropriate message. */
22287 {
22290 }
22296 {
22297 /* There is an asymmetry here in the way VAR_DECLs and
22298 FUNCTION_DECLs are handled by grokdeclarator. In the case of
22299 the latter, the DECL we get back will be marked as a
22300 template instantiation, and the appropriate
22301 DECL_TEMPLATE_INFO will be set up. This does not happen for
22302 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
22303 should handle VAR_DECLs as it currently handles
22304 FUNCTION_DECLs. */
22306 {
22309 }
22312 {
22315 }
22317 {
22322 }
22323 }
22325 {
22328 }
22329 else
22332 /* Check for various error cases. Note that if the explicit
22333 instantiation is valid the RESULT will currently be marked as an
22334 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
22335 until we get here. */
22338 {
22339 /* DR 259 [temp.spec].
22341 Both an explicit instantiation and a declaration of an explicit
22342 specialization shall not appear in a program unless the explicit
22343 instantiation follows a declaration of the explicit specialization.
22345 For a given set of template parameters, if an explicit
22346 instantiation of a template appears after a declaration of an
22347 explicit specialization for that template, the explicit
22348 instantiation has no effect. */
22350 }
22352 {
22353 /* [temp.spec]
22355 No program shall explicitly instantiate any template more
22356 than once.
22358 We check DECL_NOT_REALLY_EXTERN so as not to complain when
22359 the first instantiation was `extern' and the second is not,
22360 and EXTERN_P for the opposite case. */
22363 /* If an "extern" explicit instantiation follows an ordinary
22364 explicit instantiation, the template is instantiated. */
22367 }
22369 {
22372 }
22374 {
22377 }
22380 ;
22382 {
22385 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
22388 }
22389 else
22397 }
22399 static void
22401 {
22407 {
22410 }
22411 }
22413 /* Called from do_type_instantiation through binding_table_foreach to
22414 do recursive instantiation for the type bound in ENTRY. */
22415 static void
22417 {
22423 }
22425 /* Perform an explicit instantiation of template class T. STORAGE, if
22426 non-null, is the RID for extern, inline or static. COMPLAIN is
22427 nonzero if this is called from the parser, zero if called recursively,
22428 since the standard is unclear (as detailed below). */
22430 void
22432 {
22442 {
22443 tree tmpl =
22447 else
22450 }
22455 {
22458 t);
22460 }
22463 {
22465 {
22467 {
22470 "ISO C++ 1998 forbids the use of %<extern%> on "
22472 }
22473 else
22475 "ISO C++ forbids the use of %qE"
22477 }
22485 else
22486 {
22488 storage);
22490 }
22491 }
22494 {
22495 /* DR 259 [temp.spec].
22497 Both an explicit instantiation and a declaration of an explicit
22498 specialization shall not appear in a program unless the explicit
22499 instantiation follows a declaration of the explicit specialization.
22501 For a given set of template parameters, if an explicit
22502 instantiation of a template appears after a declaration of an
22503 explicit specialization for that template, the explicit
22504 instantiation has no effect. */
22506 }
22508 {
22509 /* [temp.spec]
22511 No program shall explicitly instantiate any template more
22512 than once.
22514 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
22515 instantiation was `extern'. If EXTERN_P then the second is.
22516 These cases are OK. */
22523 /* If we've already instantiated the template, just return now. */
22526 }
22534 /* In contrast to implicit instantiation, where only the
22535 declarations, and not the definitions, of members are
22536 instantiated, we have here:
22538 [temp.explicit]
22540 The explicit instantiation of a class template specialization
22541 implies the instantiation of all of its members not
22542 previously explicitly specialized in the translation unit
22543 containing the explicit instantiation.
22545 Of course, we can't instantiate member template classes, since we
22546 don't have any arguments for them. Note that the standard is
22547 unclear on whether the instantiation of the members are
22548 *explicit* instantiations or not. However, the most natural
22549 interpretation is that it should be an explicit
22550 instantiation. */
22554 && !static_p
22557 {
22562 }
22567 }
22569 /* Given a function DECL, which is a specialization of TMPL, modify
22570 DECL to be a re-instantiation of TMPL with the same template
22571 arguments. TMPL should be the template into which tsubst'ing
22572 should occur for DECL, not the most general template.
22574 One reason for doing this is a scenario like this:
22576 template <class T>
22577 void f(const T&, int i);
22579 void g() { f(3, 7); }
22581 template <class T>
22582 void f(const T& t, const int i) { }
22584 Note that when the template is first instantiated, with
22585 instantiate_template, the resulting DECL will have no name for the
22586 first parameter, and the wrong type for the second. So, when we go
22587 to instantiate the DECL, we regenerate it. */
22589 static void
22591 {
22592 /* The arguments used to instantiate DECL, from the most general
22593 template. */
22594 tree code_pattern;
22598 /* Make sure that we can see identifiers, and compute access
22599 correctly. */
22603 {
22604 tree decl_parm;
22605 tree pattern_parm;
22606 tree specs;
22620 specs);
22622 /* Merge parameter declarations. */
22625 pattern_parm
22629 {
22630 tree parm_type;
22631 tree attributes;
22636 NULL_TREE);
22642 {
22645 }
22648 }
22649 /* Merge any parameters that match with the function parameter
22650 pack. */
22652 {
22654 tree expanded_types;
22655 /* Expand the TYPE_PACK_EXPANSION that provides the types for
22656 the parameters in this function parameter pack. */
22661 {
22662 tree parm_type;
22663 tree attributes;
22666 /* Rename the parameter to include the index. */
22675 {
22678 }
22680 }
22681 }
22682 /* Merge additional specifiers from the CODE_PATTERN. */
22686 }
22688 {
22698 }
22699 else
22703 }
22705 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
22706 substituted to get DECL. */
22708 tree
22710 {
22713 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
22714 for the instantiation. This is not always the most general
22715 template. Consider, for example:
22717 template <class T>
22718 struct S { template <class U> void f();
22719 template <> void f<int>(); };
22721 and an instantiation of S<double>::f<int>. We want TD to be the
22722 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
22724 more general template. */
22726 /* We must also deal with friend templates. Given:
22728 template <class T> struct S {
22729 template <class U> friend void f() {};
22730 };
22732 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
22733 so far as the language is concerned, but that's still
22734 where we get the pattern for the instantiation from. On
22735 other hand, if the definition comes outside the class, say:
22737 template <class T> struct S {
22738 template <class U> friend void f();
22739 };
22740 template <class U> friend void f() {}
22742 we don't need to look any further. That's what the check for
22743 DECL_INITIAL is for. */
22747 {
22748 /* The present template, TD, should not be a definition. If it
22749 were a definition, we should be using it! Note that we
22750 cannot restructure the loop to just keep going until we find
22751 a template with a definition, since that might go too far if
22752 a specialization was declared, but not defined. */
22754 /* Fetch the more general template. */
22756 }
22759 }
22761 /* Returns true if we need to instantiate this template instance even if we
22762 know we aren't going to emit it. */
22764 bool
22766 {
22767 /* We always instantiate inline functions so that we can inline them. An
22768 explicit instantiation declaration prohibits implicit instantiation of
22769 non-inline functions. With high levels of optimization, we would
22770 normally inline non-inline functions -- but we're not allowed to do
22771 that for "extern template" functions. Therefore, we check
22772 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
22776 /* And we need to instantiate static data members so that
22777 their initializers are available in integral constant
22778 expressions. */
22781 }
22783 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
22784 instantiate it now, modifying TREE_TYPE (fn). Returns false on
22785 error, true otherwise. */
22787 bool
22789 {
22792 /* Don't instantiate a noexcept-specification from template context. */
22807 {
22813 {
22814 /* If hash_set::add returns true, the element was already there. */
22819 fn);
22821 }
22823 {
22838 }
22839 else
22849 }
22852 {
22855 else
22857 }
22860 }
22862 /* We're starting to process the function INST, an instantiation of PATTERN;
22863 add their parameters to local_specializations. */
22865 static void
22867 {
22871 {
22875 }
22877 {
22879 {
22882 }
22883 else
22884 {
22885 /* Register the (value) argument pack as a specialization of
22886 TMPL_PARM, then move on. */
22889 }
22890 }
22892 }
22894 /* Produce the definition of D, a _DECL generated from a template. If
22895 DEFER_OK is true, then we don't have to actually do the
22896 instantiation now; we just have to do it sometime. Normally it is
22897 an error if this is an explicit instantiation but D is undefined.
22898 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
22899 instantiated class template. */
22901 tree
22903 {
22905 tree gen_args;
22906 tree args;
22907 tree td;
22908 tree code_pattern;
22909 tree spec;
22910 tree gen_tmpl;
22918 /* This function should only be used to instantiate templates for
22919 functions and static member variables. */
22922 /* A concept is never instantiated. */
22925 /* Variables are never deferred; if instantiation is required, they
22926 are instantiated right away. That allows for better code in the
22927 case that an expression refers to the value of the variable --
22928 if the variable has a constant value the referring expression can
22929 take advantage of that fact. */
22933 /* Don't instantiate cloned functions. Instead, instantiate the
22934 functions they cloned. */
22942 /* D has already been instantiated or explicitly specialized, so
22943 there's nothing for us to do here.
22945 It might seem reasonable to check whether or not D is an explicit
22946 instantiation, and, if so, stop here. But when an explicit
22947 instantiation is deferred until the end of the compilation,
22948 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
22949 the instantiation. */
22952 /* Check to see whether we know that this template will be
22953 instantiated in some other file, as with "extern template"
22954 extension. */
22957 /* In general, we do not instantiate such templates. */
22965 /* We should already have the extra args. */
22968 /* And what's in the hash table should match D. */
22972 /* This needs to happen before any tsubsting. */
22978 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
22979 for the instantiation. */
22984 {
22985 /* Look up an explicit specialization, if any. */
22989 {
22992 }
22993 }
22997 /* We should never be trying to instantiate a member of a class
22998 template or partial specialization. */
23003 /* In the case of a friend template whose definition is provided
23004 outside the class, we may have too many arguments. Drop the
23005 ones we don't need. The same is true for specializations. */
23006 args = get_innermost_template_args
23010 {
23016 }
23017 else
23018 {
23023 else
23025 }
23027 /* We may be in the middle of deferred access check. Disable it now. */
23030 /* Unless an explicit instantiation directive has already determined
23031 the linkage of D, remember that a definition is available for
23032 this entity. */
23042 /* If D is a member of an explicitly instantiated class template,
23043 and no definition is available, treat it like an implicit
23044 instantiation. */
23047 {
23048 /* Leave linkage flags alone on instantiations with anonymous
23049 visibility. */
23051 {
23054 }
23056 }
23058 /* Defer all other templates, unless we have been explicitly
23059 forbidden from doing so. */
23061 template. */
23062 ! pattern_defined
23063 /* If it's OK to postpone instantiation, do so. */
23064 || defer_ok
23065 /* If this is a static data member that will be defined
23066 elsewhere, we don't want to instantiate the entire data
23067 member, but we do want to instantiate the initializer so that
23068 we can substitute that elsewhere. */
23070 /* Handle here a deleted function too, avoid generating
23071 its body (c++/61080). */
23073 {
23074 /* The definition of the static data member is now required so
23075 we must substitute the initializer. */
23079 {
23080 tree ns;
23081 tree init;
23090 args,
23093 /* If instantiating the initializer involved instantiating this
23094 again, don't call cp_finish_decl twice. */
23096 {
23097 /* Make sure the initializer is still constant, in case of
23098 circular dependency (template/instantiate6.C). */
23099 const_init
23103 LOOKUP_ONLYCONVERTING);
23104 }
23108 }
23110 /* We restore the source position here because it's used by
23111 add_pending_template. */
23117 /* [temp.explicit]
23119 The definition of a non-exported function template, a
23120 non-exported member function template, or a non-exported
23121 member function or static data member of a class template
23122 shall be present in every translation unit in which it is
23123 explicitly instantiated. */
23127 /* If we're in unevaluated context, we just wanted to get the
23128 constant value; this isn't an odr use, so don't queue
23129 a full instantiation. */
23132 /* ??? Historically, we have instantiated inline functions, even
23133 when marked as "extern template". */
23137 }
23138 /* Tell the repository that D is available in this translation unit
23139 -- and see if it is supposed to be instantiated here. */
23141 {
23142 /* In a PCH file, despite the fact that the repository hasn't
23143 requested instantiation in the PCH it is still possible that
23144 an instantiation will be required in a file that includes the
23145 PCH. */
23148 /* Instantiate inline functions so that the inliner can do its
23149 job, even though we'll not be emitting a copy of this
23150 function. */
23153 }
23156 tree fn_context;
23167 else
23168 {
23172 }
23174 /* Mark D as instantiated so that recursive calls to
23175 instantiate_decl do not try to instantiate it again. */
23178 /* Regenerate the declaration in case the template has been modified
23179 by a subsequent redeclaration. */
23182 /* We already set the file and line above. Reset them now in case
23183 they changed as a result of calling regenerate_decl_from_template. */
23187 {
23188 tree init;
23191 /* Clear out DECL_RTL; whatever was there before may not be right
23192 since we've reset the type of the declaration. */
23196 /* The initializer is placed in DECL_INITIAL by
23197 regenerate_decl_from_template so we don't need to
23198 push/pop_access_scope again here. Pull it out so that
23199 cp_finish_decl can process it. */
23204 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
23205 initializer. That function will defer actual emission until
23206 we have a chance to determine linkage. */
23209 /* Enter the scope of D so that access-checking works correctly. */
23222 }
23226 {
23227 /* Set up the list of local specializations. */
23231 /* Set up context. */
23235 else
23238 /* Some typedefs referenced from within the template code need to be
23239 access checked at template instantiation time, i.e now. These
23240 types were added to the template at parsing time. Let's get those
23241 and perform the access checks then. */
23243 args);
23245 /* Create substitution entries for the parameters. */
23248 /* Substitute into the body of the function. */
23252 else
23253 {
23258 /* Set the current input_location to the end of the function
23259 so that finish_function knows where we are. */
23260 input_location
23263 /* Remember if we saw an infinite loop in the template. */
23264 current_function_infinite_loop
23266 }
23268 /* Finish the function. */
23272 else
23273 {
23276 }
23280 }
23282 /* We're not deferring instantiation any more. */
23287 else
23293 out:
23302 }
23304 /* Run through the list of templates that we wish we could
23305 instantiate, and instantiate any we can. RETRIES is the
23306 number of times we retry pending template instantiation. */
23308 void
23310 {
23314 /* Instantiating templates may trigger vtable generation. This in turn
23315 may require further template instantiations. We place a limit here
23316 to avoid infinite loop. */
23318 {
23322 "template instantiation depth exceeds maximum of %d"
23323 " instantiating %q+D, possibly from virtual table generation"
23327 /* Pretend that we defined it. */
23330 }
23332 do
23333 {
23338 {
23343 {
23345 {
23360 }
23363 }
23364 else
23365 {
23368 {
23369 instantiation
23375 }
23379 }
23382 /* If INSTANTIATION has been instantiated, then we don't
23383 need to consider it again in the future. */
23385 else
23386 {
23389 }
23392 }
23394 }
23398 }
23400 /* Substitute ARGVEC into T, which is a list of initializers for
23401 either base class or a non-static data member. The TREE_PURPOSEs
23402 are DECLs, and the TREE_VALUEs are the initializer values. Used by
23403 instantiate_decl. */
23405 static tree
23407 {
23411 {
23412 tree decl;
23413 tree init;
23419 {
23420 tree expr;
23421 tree arg;
23423 /* Expand the base class expansion type into separate base
23424 classes. */
23426 tf_warning_or_error,
23427 NULL_TREE);
23431 /* We'll be building separate TREE_LISTs of arguments for
23432 each base. */
23438 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
23439 expand each argument in the TREE_VALUE of t. */
23446 /* VOID_TYPE_NODE is used to indicate
23447 value-initialization. */
23448 {
23451 }
23452 else
23453 {
23454 /* Substitute parameter packs into each argument in the
23455 TREE_LIST. */
23458 {
23459 tree expanded_exprs;
23461 /* Expand the argument. */
23463 expanded_exprs
23465 tf_warning_or_error,
23466 NULL_TREE);
23470 /* Prepend each of the expanded expressions to the
23471 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
23473 {
23478 }
23479 }
23482 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
23483 since we built them backwards. */
23485 {
23488 }
23489 }
23490 }
23493 {
23495 {
23499 }
23500 else
23501 {
23502 tree tmp;
23517 /* If we had an initializer but it instantiated to nothing,
23518 value-initialize the object. This will only occur when
23519 the initializer was a pack expansion where the parameter
23520 packs used in that expansion were of length zero. */
23523 }
23526 {
23530 }
23531 }
23532 }
23534 }
23536 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
23538 static void
23540 {
23545 else
23547 }
23549 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
23550 is the instantiation (which should have been created with
23551 start_enum) and ARGS are the template arguments to use. */
23553 static void
23555 {
23556 tree e;
23562 {
23563 tree value;
23564 tree decl;
23567 /* Note that in a template enum, the TREE_VALUE is the
23568 CONST_DECL, not the corresponding INTEGER_CST. */
23573 /* Give this enumeration constant the correct access. */
23576 /* Actually build the enumerator itself. Here we're assuming that
23577 enumerators can't have dependent attributes. */
23580 }
23590 }
23592 /* DECL is a FUNCTION_DECL that is a template specialization. Return
23593 its type -- but without substituting the innermost set of template
23594 arguments. So, innermost set of template parameters will appear in
23595 the type. */
23597 tree
23599 {
23600 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
23602 }
23604 /* Return truthvalue if we're processing a template different from
23605 the last one involved in diagnostics. */
23606 bool
23608 {
23610 }
23612 /* Remember current template involved in diagnostics. */
23613 void
23615 {
23617 }
23621 {
23623 }
23625 /* Return TRUE if current_function_decl is being instantiated, false
23626 otherwise. */
23628 bool
23630 {
23633 }
23635 /* [temp.param] Check that template non-type parm TYPE is of an allowable
23636 type. Return zero for ok, nonzero for disallowed. Issue error and
23637 warning messages under control of COMPLAIN. */
23639 static int
23641 {
23656 /* A bound template template parm could later be instantiated to have a valid
23657 nontype parm type via an alias template. */
23663 {
23666 else
23668 type);
23669 }
23671 }
23673 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
23674 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
23676 static bool
23678 {
23679 tree scope;
23681 /* [temp.dep.type]
23683 A type is dependent if it is:
23685 -- a template parameter. Template template parameters are types
23686 for us (since TYPE_P holds true for them) so we handle
23687 them here. */
23691 /* -- a qualified-id with a nested-name-specifier which contains a
23692 class-name that names a dependent type or whose unqualified-id
23693 names a dependent type. */
23697 /* An alias template specialization can be dependent even if the
23698 resulting type is not. */
23702 /* -- a cv-qualified type where the cv-unqualified type is
23703 dependent.
23704 No code is necessary for this bullet; the code below handles
23705 cv-qualified types, and we don't want to strip aliases with
23706 TYPE_MAIN_VARIANT because of DR 1558. */
23707 /* -- a compound type constructed from any dependent type. */
23717 {
23718 tree arg_type;
23723 arg_type;
23728 {
23729 /* A value-dependent noexcept-specifier makes the type dependent. */
23734 }
23736 }
23737 /* -- an array type constructed from any dependent type or whose
23738 size is specified by a constant expression that is
23739 value-dependent.
23741 We checked for type- and value-dependence of the bounds in
23742 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
23744 {
23749 }
23751 /* -- a template-id in which either the template name is a template
23752 parameter ... */
23755 /* ... or any of the template arguments is a dependent type or
23756 an expression that is type-dependent or value-dependent. */
23758 && (any_dependent_template_arguments_p
23762 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
23763 dependent; if the argument of the `typeof' expression is not
23764 type-dependent, then it should already been have resolved. */
23770 /* A template argument pack is dependent if any of its packed
23771 arguments are. */
23773 {
23779 }
23781 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
23782 be template parameters. */
23789 /* The standard does not specifically mention types that are local
23790 to template functions or local classes, but they should be
23791 considered dependent too. For example:
23793 template <int I> void f() {
23794 enum E { a = I };
23795 S<sizeof (E)> s;
23796 }
23798 The size of `E' cannot be known until the value of `I' has been
23799 determined. Therefore, `E' must be considered dependent. */
23803 /* Don't use type_dependent_expression_p here, as it can lead
23804 to infinite recursion trying to determine whether a lambda
23805 nested in a lambda is dependent (c++/47687). */
23809 && (any_dependent_template_arguments_p
23813 /* Other types are non-dependent. */
23815 }
23817 /* Returns TRUE if TYPE is dependent, in the sense of
23818 [temp.dep.type]. Note that a NULL type is considered dependent. */
23820 bool
23822 {
23823 /* If there are no template parameters in scope, then there can't be
23824 any dependent types. */
23826 {
23827 /* If we are not processing a template, then nobody should be
23828 providing us with a dependent type. */
23832 }
23834 /* If the type is NULL, we have not computed a type for the entity
23835 in question; in that case, the type is dependent. */
23839 /* Erroneous types can be considered non-dependent. */
23843 /* Getting here with global_type_node means we improperly called this
23844 function on the TREE_TYPE of an IDENTIFIER_NODE. */
23847 /* If we have not already computed the appropriate value for TYPE,
23848 do so now. */
23850 {
23853 }
23856 }
23858 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
23859 lookup. In other words, a dependent type that is not the current
23860 instantiation. */
23862 bool
23864 {
23867 }
23869 /* T is a SCOPE_REF; return whether we need to consider it
23870 instantiation-dependent so that we can check access at instantiation
23871 time even though we know which member it resolves to. */
23873 static bool
23875 {
23881 else
23883 }
23885 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
23886 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
23887 expression. */
23889 /* Note that this predicate is not appropriate for general expressions;
23890 only constant expressions (that satisfy potential_constant_expression)
23891 can be tested for value dependence. */
23893 bool
23895 {
23899 /* A name declared with a dependent type. */
23904 {
23906 /* A dependent member function of the current instantiation. */
23910 /* A dependent member function of the current instantiation. */
23917 /* A name that has not been looked up -- must be dependent. */
23921 /* A non-type template parm. */
23925 /* A non-type template parm. */
23931 /* A constant with literal type and is initialized
23932 with an expression that is value-dependent.
23934 Note that a non-dependent parenthesized initializer will have
23935 already been replaced with its constant value, so if we see
23936 a TREE_LIST it must be dependent. */
23940 /* cp_finish_decl doesn't fold reference initializers. */
23946 {
23950 }
23958 /* These expressions are value-dependent if the type to which
23959 the cast occurs is dependent or the expression being casted
23960 is value-dependent. */
23961 {
23967 /* A functional cast has a list of operands. */
23970 {
23971 /* If there are no operands, it must be an expression such
23972 as "int()". This should not happen for aggregate types
23973 because it would form non-constant expressions. */
23978 }
23984 }
23989 /* FALLTHRU */
23992 /* A `sizeof' expression is value-dependent if the operand is
23993 type-dependent or is a pack expansion. */
24002 /* An 'encode' expression is value-dependent if the operand is
24003 type-dependent. */
24012 /* All instantiation-dependent expressions should also be considered
24013 value-dependent. */
24021 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
24022 is value-dependent. */
24023 {
24032 }
24035 {
24039 }
24050 {
24054 }
24057 /* Treat all requires-expressions as value-dependent so
24058 we don't try to fold them. */
24065 {
24072 {
24074 /* In a call to a constexpr member function, look through the
24075 implicit ADDR_EXPR on the object argument so that it doesn't
24076 cause the call to be considered value-dependent. We also
24077 look through it in potential_constant_expression. */
24084 }
24086 }
24089 /* If a TEMPLATE_ID_EXPR involves a dependent name, it will be
24090 type-dependent. */
24095 {
24097 tree val;
24104 }
24107 /* Treat a GNU statement expression as dependent to avoid crashing
24108 under instantiate_non_dependent_expr; it can't be constant. */
24112 /* A constant expression is value-dependent if any subexpression is
24113 value-dependent. */
24115 {
24122 {
24126 {
24129 /* In some cases, some of the operands may be missing.
24130 (For example, in the case of PREDECREMENT_EXPR, the
24131 amount to increment by may be missing.) That doesn't
24132 make the expression dependent. */
24135 }
24136 }
24140 }
24142 }
24144 /* The expression is not value-dependent. */
24146 }
24148 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
24149 [temp.dep.expr]. Note that an expression with no type is
24150 considered dependent. Other parts of the compiler arrange for an
24151 expression with type-dependent subexpressions to have no type, so
24152 this function doesn't have to be fully recursive. */
24154 bool
24156 {
24163 /* An unresolved name is always dependent. */
24169 /* A fold expression is type-dependent. */
24176 /* Some expression forms are never type-dependent. */
24190 /* The types of these expressions depends only on the type to which
24191 the cast occurs. */
24200 /* The types of these expressions depends only on the type created
24201 by the expression. */
24204 {
24205 /* For NEW_EXPR tree nodes created inside a template, either
24206 the object type itself or a TREE_LIST may appear as the
24207 operand 1. */
24210 /* This is an array type. We need to check array dimensions
24211 as well. */
24213 || value_dependent_expression_p
24215 else
24217 }
24220 {
24224 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
24225 contains an identifier associated by name lookup with one or more
24226 declarations declared with a dependent type, or...a
24227 nested-name-specifier or qualified-id that names a member of an
24228 unknown specialization. */
24231 }
24241 {
24242 tree elt;
24246 {
24249 }
24251 }
24253 /* A static data member of the current instantiation with incomplete
24254 array type is type-dependent, as the definition and specializations
24255 can have different bounds. */
24262 /* An array of unknown bound depending on a variadic parameter, eg:
24264 template<typename... Args>
24265 void foo (Args... args)
24266 {
24267 int arr[] = { args... };
24268 }
24270 template<int... vals>
24271 void bar ()
24272 {
24273 int arr[] = { vals... };
24274 }
24276 If the array has no length and has an initializer, it must be that
24277 we couldn't determine its length in cp_complete_array_type because
24278 it is dependent. */
24286 /* A function or variable template-id is type-dependent if it has any
24287 dependent template arguments. */
24291 {
24292 /* Consider the innermost template arguments, since those are the ones
24293 that come from the template-id; the template arguments for the
24294 enclosing class do not make it type-dependent unless they are used in
24295 the type of the decl. */
24297 && (any_dependent_template_arguments_p
24300 }
24302 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
24303 type-dependent. Checking this is important for functions with auto return
24304 type, which looks like a dependent type. */
24312 {
24316 }
24318 /* Always dependent, on the number of arguments if nothing else. */
24323 {
24328 {
24334 }
24335 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
24340 {
24345 }
24348 {
24355 }
24365 }
24369 /* Dependent type attributes might not have made it from the decl to
24370 the type yet. */
24376 }
24378 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
24379 type-dependent if the expression refers to a member of the current
24380 instantiation and the type of the referenced member is dependent, or the
24381 class member access expression refers to a member of an unknown
24382 specialization.
24384 This function returns true if the OBJECT in such a class member access
24385 expression is of an unknown specialization. */
24387 bool
24389 {
24390 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
24391 dependent. */
24396 }
24398 /* walk_tree callback function for instantiation_dependent_expression_p,
24399 below. Returns non-zero if a dependent subexpression is found. */
24401 static tree
24404 {
24406 {
24407 /* We don't have to worry about decltype currently because decltype
24408 of an instantiation-dependent expr is a dependent type. This
24409 might change depending on the resolution of DR 1172. */
24412 }
24415 {
24416 /* Don't treat an argument list as dependent just because it has no
24417 TREE_TYPE. */
24425 /* Handle expressions with type operands. */
24430 {
24435 {
24438 else
24439 {
24442 }
24443 }
24445 }
24449 /* In a template, finish_class_member_access_expr creates a
24450 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
24451 type-dependent, so that we can check access control at
24452 instantiation time (PR 42277). See also Core issue 1273. */
24459 else
24462 /* Treat statement-expressions as dependent. */
24466 /* Treat requires-expressions as dependent. */
24471 /* Treat calls to function concepts as dependent. */
24477 /* And variable concepts. */
24484 }
24488 else
24490 }
24492 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
24493 sense defined by the ABI:
24495 "An expression is instantiation-dependent if it is type-dependent
24496 or value-dependent, or it has a subexpression that is type-dependent
24497 or value-dependent."
24499 Except don't actually check value-dependence for unevaluated expressions,
24500 because in sizeof(i) we don't care about the value of i. Checking
24501 type-dependence will in turn check value-dependence of array bounds/template
24502 arguments as needed. */
24504 bool
24506 {
24507 tree result;
24518 }
24520 /* As above, but also check value-dependence of the expression as a whole. */
24522 bool
24524 {
24527 }
24529 /* Like type_dependent_expression_p, but it also works while not processing
24530 a template definition, i.e. during substitution or mangling. */
24532 bool
24534 {
24540 }
24542 /* Returns TRUE if ARGS contains a type-dependent expression. */
24544 bool
24546 {
24548 tree arg;
24551 {
24554 }
24556 }
24558 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24559 expressions) contains any type-dependent expressions. */
24561 bool
24563 {
24569 }
24571 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24572 expressions) contains any value-dependent expressions. */
24574 bool
24576 {
24582 }
24584 /* Returns TRUE if the ARG (a template argument) is dependent. */
24586 bool
24588 {
24592 /* Assume a template argument that was wrongly written by the user
24593 is dependent. This is consistent with what
24594 any_dependent_template_arguments_p [that calls this function]
24595 does. */
24605 {
24608 /* A member template of a dependent class is not necessarily
24609 type-dependent, but it is a dependent template argument because it
24610 will be a member of an unknown specialization to that template. */
24613 }
24615 {
24619 {
24622 }
24625 }
24628 else
24631 }
24633 /* Returns true if ARGS (a collection of template arguments) contains
24634 any types that require structural equality testing. */
24636 bool
24638 {
24648 {
24651 {
24657 {
24658 /* Look inside the argument pack. */
24661 }
24664 {
24677 }
24678 }
24679 }
24682 }
24684 /* Returns true if ARGS (a collection of template arguments) contains
24685 any dependent arguments. */
24687 bool
24689 {
24699 {
24704 }
24707 }
24709 /* Returns TRUE if the template TMPL is type-dependent. */
24711 bool
24713 {
24715 {
24720 }
24722 /* Template template parameters are dependent. */
24726 /* So are names that have not been looked up. */
24730 }
24732 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
24734 bool
24736 {
24739 }
24741 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
24742 are dependent. */
24744 bool
24746 {
24753 {
24775 {
24779 }
24783 {
24787 {
24792 }
24793 }
24794 }
24797 }
24799 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
24800 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
24801 no such TYPE can be found. Note that this function peers inside
24802 uninstantiated templates and therefore should be used only in
24803 extremely limited situations. ONLY_CURRENT_P restricts this
24804 peering to the currently open classes hierarchy (which is required
24805 when comparing types). */
24807 tree
24809 {
24810 tree scope;
24811 tree name;
24812 tree decl;
24814 tree pushed_scope;
24815 tree result;
24820 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
24821 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
24822 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
24823 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
24824 identifier of the TYPENAME_TYPE anymore.
24825 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
24826 TYPENAME_TYPE instead, we avoid messing up with a possible
24827 typedef variant case. */
24830 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
24831 it first before we can figure out what NAME refers to. */
24833 {
24835 /* Given a class template A with a dependent base with nested type C,
24836 typedef typename A::C::C C will land us here, as trying to resolve
24837 the initial A::C leads to the local C typedef, which leads back to
24838 A::C::C. So we break the recursion now. */
24840 else
24842 }
24843 /* If we don't know what SCOPE refers to, then we cannot resolve the
24844 TYPENAME_TYPE. */
24847 /* If this is a typedef, we don't want to look inside (c++/11987). */
24850 /* If SCOPE isn't the template itself, it will not have a valid
24851 TYPE_FIELDS list. */
24853 /* scope is either the template itself or a compatible instantiation
24854 like X<T>, so look up the name in the original template. */
24856 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
24858 /* If scope has no fields, it can't be a current instantiation. Check this
24859 before currently_open_class to avoid infinite recursion (71515). */
24862 /* If the SCOPE is not the current instantiation, there's no reason
24863 to look inside it. */
24866 /* Enter the SCOPE so that name lookup will be resolved as if we
24867 were in the class definition. In particular, SCOPE will no
24868 longer be considered a dependent type. */
24870 /* Look up the declaration. */
24872 tf_warning_or_error);
24876 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
24877 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
24883 {
24887 }
24890 {
24891 /* Obtain the template and the arguments. */
24894 {
24895 /* We get here with a plain identifier because a previous tentative
24896 parse of the nested-name-specifier as part of a ptr-operator saw
24897 ::template X<A>. The use of ::template is necessary in a
24898 ptr-operator, but wrong in a declarator-id.
24900 [temp.names]: In a qualified-id of a declarator-id, the keyword
24901 template shall not appear at the top level. */
24905 }
24907 /* Instantiate the template. */
24913 }
24915 /* Leave the SCOPE. */
24919 /* If we failed to resolve it, return the original typename. */
24923 /* If lookup found a typename type, resolve that too. */
24925 {
24926 /* Ill-formed programs can cause infinite recursion here, so we
24927 must catch that. */
24931 }
24933 /* Qualify the resulting type. */
24939 }
24941 /* EXPR is an expression which is not type-dependent. Return a proxy
24942 for EXPR that can be used to compute the types of larger
24943 expressions containing EXPR. */
24945 tree
24947 {
24948 tree inner_expr;
24950 /* When checking, try to get a constant value for all non-dependent
24951 expressions in order to expose bugs in *_dependent_expression_p
24952 and constexpr. This can affect code generation, see PR70704, so
24953 only do this for -fchecking=2. */
24956 /* Don't do this during nsdmi parsing as it can lead to
24957 unexpected recursive instantiations. */
24959 /* Don't do this during concept expansion either and for
24960 the same reason. */
24964 /* Preserve OVERLOADs; the functions must be available to resolve
24965 types. */
24976 /* There is no need to return a proxy for a variable. */
24979 /* Preserve string constants; conversions from string constants to
24980 "char *" are allowed, even though normally a "const char *"
24981 cannot be used to initialize a "char *". */
24984 /* Preserve void and arithmetic constants, as an optimization -- there is no
24985 reason to create a new node. */
24990 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
24991 There is at least one place where we want to know that a
24992 particular expression is a throw-expression: when checking a ?:
24993 expression, there are special rules if the second or third
24994 argument is a throw-expression. */
24998 /* Don't wrap an initializer list, we need to be able to look inside. */
25002 /* Don't wrap a dummy object, we need to be able to test for it. */
25021 /* If the type is unknown, it can't really be non-dependent */
25024 /* Otherwise, build a NON_DEPENDENT_EXPR. */
25026 }
25028 /* ARGS is a vector of expressions as arguments to a function call.
25029 Replace the arguments with equivalent non-dependent expressions.
25030 This modifies ARGS in place. */
25032 void
25034 {
25036 tree arg;
25039 {
25043 }
25044 }
25046 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
25047 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
25048 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
25050 static tree
25052 {
25066 }
25068 tree
25070 {
25072 }
25074 tree
25076 {
25078 }
25080 /* Return a C++17 deduction placeholder for class template TMPL. */
25082 tree
25084 {
25088 }
25090 /* True iff T is a C++17 class template deduction placeholder. */
25092 bool
25094 {
25096 }
25098 /* Make a "constrained auto" type-specifier. This is an
25099 auto type with constraints that must be associated after
25100 deduction. The constraint is formed from the given
25101 CONC and its optional sequence of arguments, which are
25102 non-null if written as partial-concept-id. */
25104 tree
25106 {
25109 /* Build the constraint. */
25117 /* Our canonical type depends on the constraint. */
25120 /* Attach the constraint to the type declaration. */
25123 }
25125 /* Given type ARG, return std::initializer_list<ARG>. */
25127 static tree
25129 {
25133 {
25137 "deducing from brace-enclosed initializer list"
25141 }
25147 }
25149 /* Replace auto in TYPE with std::initializer_list<auto>. */
25151 static tree
25153 {
25160 }
25162 /* Hash traits for hashing possibly constrained 'auto'
25163 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
25166 {
25169 };
25171 /* Hash the 'auto' T. */
25173 inline hashval_t
25175 {
25177 /* Matching constrained-type-specifiers denote the same template
25178 parameter, so hash the constraint. */
25180 else
25181 /* But unconstrained autos are all separate, so just hash the pointer. */
25183 }
25185 /* Compare two 'auto's. */
25189 {
25196 /* Two unconstrained autos are distinct. */
25201 }
25203 /* for_each_template_parm callback for extract_autos: if t is a (possibly
25204 constrained) auto, add it to the vector. */
25206 static int
25208 {
25211 {
25212 /* All the autos were built with index 0; fix that up now. */
25216 /* If this is a repeated constrained-type-specifier, use the index we
25217 chose before. */
25219 else
25220 {
25221 /* Otherwise this is new, so use the current count. */
25224 }
25226 }
25228 /* Always keep walking. */
25230 }
25232 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
25233 says they can appear anywhere in the type. */
25235 static tree
25237 {
25246 {
25251 }
25254 }
25256 /* The stem for deduction guide names. */
25259 /* Return the name for a deduction guide for class template TMPL. */
25261 tree
25263 {
25274 }
25276 /* True if NAME is the name of a deduction guide. */
25278 bool
25280 {
25284 }
25286 /* True if FN is a deduction guide. */
25288 bool
25290 {
25295 }
25297 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
25299 bool
25301 {
25308 }
25310 /* True if FN is a guide generated from a constructor template. */
25312 bool
25314 {
25322 }
25324 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
25325 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
25326 template parameter types. Note that the handling of template template
25327 parameters relies on current_template_parms being set appropriately for the
25328 new template. */
25330 static tree
25333 {
25336 tree newtype;
25339 {
25346 }
25347 else
25351 tree newdecl
25356 tree newidx;
25359 {
25369 {
25374 // First create a copy (ttargs) of tsubst_args with an
25375 // additional level for the template template parameter's own
25376 // template parameters (ttparms).
25377 tree ttparms = (INNERMOST_TEMPLATE_PARMS
25385 // Substitute ttargs into ttparms to fix references to
25386 // other template parameters.
25388 complain);
25389 // Now substitute again with args based on tparms, to reduce
25390 // the level of the ttparms.
25393 complain);
25394 // Finally, tack the adjusted parms onto tparms.
25396 current_template_parms);
25398 }
25399 }
25400 else
25401 {
25403 tree newconst
25415 }
25418 }
25420 /* Returns a C++17 class deduction guide template based on the constructor
25421 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
25422 guide, or REFERENCE_TYPE for an implicit copy/move guide. */
25424 static tree
25426 {
25430 location_t loc;
25434 {
25438 {
25441 }
25442 else
25452 }
25453 else
25454 {
25457 fn_tmpl
25467 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
25468 fully specialized args for the enclosing class. Strip those off, as
25469 the deduction guide won't have those template parameters. */
25472 /* Discard the 'this' parameter. */
25480 {
25483 /* For a member template constructor, we need to flatten the two
25484 template parameter lists into one, and then adjust the function
25485 signature accordingly. This gets...complicated. */
25488 /* For a member template we should have two levels of parms/args, one
25489 for the class and one for the constructor. We stripped
25490 specialized args for further enclosing classes above. */
25494 /* Template args for translating references to the two-level template
25495 parameters into references to the one-level template parameters we
25496 are creating. */
25501 /* Template parms for the constructor template. */
25504 /* Template parms for the class template. */
25508 /* Template parms for the deduction guide start as a copy of the
25509 template parms for the class. We set current_template_parms for
25510 lookup_template_class_1. */
25516 /* Now we need to rewrite the constructor parms to append them to the
25517 class parms. */
25519 {
25534 }
25536 /* Now we have a final set of template parms to substitute into the
25537 function signature. */
25546 }
25548 }
25551 {
25552 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
25556 }
25560 FUNCTION_DECL,
25577 }
25579 /* Deduce template arguments for the class template placeholder PTYPE for
25580 template TMPL based on the initializer INIT, and return the resulting
25581 type. */
25583 static tree
25585 tsubst_flags_t complain)
25586 {
25588 {
25589 /* We should have handled this in the caller. */
25595 }
25606 {
25609 {
25610 /* As an exception, the first phase in 16.3.1.7 (considering the
25611 initializer list as a single argument) is omitted if the
25612 initializer list consists of a single expression of type cv U,
25613 where U is a specialization of C or a class derived from a
25614 specialization of C. */
25625 }
25628 else
25630 }
25631 else
25642 /* Prune explicit deduction guides in copy-initialization context. */
25644 {
25650 {
25651 /* Found a nonconverting guide, prune the candidates. */
25658 }
25659 }
25664 {
25667 }
25670 // FIXME cache artificial deduction guides
25672 {
25677 else
25681 }
25685 /* If this is list-initialization and the class has a list constructor, first
25686 try deducing from the list as a single argument, as [over.match.list]. */
25690 {
25694 }
25696 {
25702 {
25703 /* That didn't work, now try treating the list as a sequence of
25704 arguments. */
25707 }
25708 }
25710 /* Maybe generate an implicit deduction guide. */
25712 {
25716 /* Generate a copy guide. */
25719 /* Generate a default guide. */
25723 {
25726 }
25727 }
25730 {
25732 " of %qT, as it has no non-explicit deduction guides or "
25735 }
25737 {
25741 }
25744 {
25748 }
25751 {
25761 }
25766 }
25768 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25769 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
25771 tree
25773 {
25775 tf_warning_or_error,
25776 adc_unspecified);
25777 }
25779 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25780 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
25781 The CONTEXT determines the context in which auto deduction is performed
25782 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
25783 OUTER_TARGS are used during template argument deduction
25784 (context == adc_unify) to properly substitute the result, and is ignored
25785 in other contexts.
25787 For partial-concept-ids, extra args may be appended to the list of deduced
25788 template arguments prior to determining constraint satisfaction. */
25790 tree
25794 {
25795 tree targs;
25802 /* Defining a subset of type-dependent expressions that we can deduce
25803 from ahead of time isn't worth the trouble. */
25807 /* C++17 class template argument deduction. */
25811 /* Nothing we can do with this, even in deduction context. */
25814 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
25815 with either a new invented type template parameter U or, if the
25816 initializer is a braced-init-list (8.5.4), with
25817 std::initializer_list<U>. */
25819 {
25824 else
25825 {
25827 {
25831 "for deduction to %<std::initializer_list%>, use copy-"
25833 }
25835 }
25836 }
25847 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
25848 and initializer has array type, deduce cv-qualified array type. */
25850 complain);
25852 {
25861 {
25865 }
25866 }
25867 else
25868 {
25870 tree tparms;
25874 else
25875 {
25879 }
25886 {
25888 /* Try again at instantiation time. */
25892 /* If type is error_mark_node a diagnostic must have been
25893 emitted by now. Also, having a mention to '<type error>'
25894 in the diagnostic is not really useful to the user. */
25895 {
25899 else
25904 }
25906 }
25907 }
25909 /* Check any placeholder constraints against the deduced type. */
25912 {
25913 /* Use the deduced type to check the associated constraints. If we
25914 have a partial-concept-id, rebuild the argument list so that
25915 we check using the extra arguments. */
25919 {
25922 }
25923 else
25926 {
25928 {
25930 {
25948 }
25950 }
25952 }
25953 }
25959 }
25961 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
25962 result. */
25964 tree
25966 {
25968 {
25974 /* In an abbreviated function template we didn't know we were dealing
25975 with a function template when we saw the auto return type, so update
25976 it to have the correct level. */
25978 }
25980 }
25982 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
25983 'decltype(auto)' or a deduced class template. */
25985 bool
25987 {
25993 else
25995 }
25997 /* for_each_template_parm callback for type_uses_auto. */
25999 int
26001 {
26003 }
26005 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
26006 a use of `auto'. Returns NULL_TREE otherwise. */
26008 tree
26010 {
26014 {
26015 /* The Concepts TS allows multiple autos in one type-specifier; just
26016 return the first one we find, do_auto_deduction will collect all of
26017 them. */
26021 else
26023 }
26024 else
26026 }
26028 /* For a given template T, return the vector of typedefs referenced
26029 in T for which access check is needed at T instantiation time.
26030 T is either a FUNCTION_DECL or a RECORD_TYPE.
26031 Those typedefs were added to T by the function
26032 append_type_to_template_for_access_check. */
26036 {
26037 tree ti;
26048 {
26053 }
26056 }
26058 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
26059 tied to T. That list of typedefs will be access checked at
26060 T instantiation time.
26061 T is either a FUNCTION_DECL or a RECORD_TYPE.
26062 TYPE_DECL is a TYPE_DECL node representing a typedef.
26063 SCOPE is the scope through which TYPE_DECL is accessed.
26064 LOCATION is the location of the usage point of TYPE_DECL.
26066 This function is a subroutine of
26067 append_type_to_template_for_access_check. */
26069 static void
26071 tree type_decl,
26072 tree scope,
26073 location_t location)
26074 {
26075 qualified_typedef_usage_t typedef_usage;
26076 tree ti;
26083 && type_decl
26097 }
26099 /* Append TYPE_DECL to the template TEMPL.
26100 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
26101 At TEMPL instanciation time, TYPE_DECL will be checked to see
26102 if it can be accessed through SCOPE.
26103 LOCATION is the location of the usage point of TYPE_DECL.
26105 e.g. consider the following code snippet:
26107 class C
26108 {
26109 typedef int myint;
26110 };
26112 template<class U> struct S
26113 {
26114 C::myint mi; // <-- usage point of the typedef C::myint
26115 };
26117 S<char> s;
26119 At S<char> instantiation time, we need to check the access of C::myint
26120 In other words, we need to check the access of the myint typedef through
26121 the C scope. For that purpose, this function will add the myint typedef
26122 and the scope C through which its being accessed to a list of typedefs
26123 tied to the template S. That list will be walked at template instantiation
26124 time and access check performed on each typedefs it contains.
26125 Note that this particular code snippet should yield an error because
26126 myint is private to C. */
26128 void
26130 tree type_decl,
26131 tree scope,
26132 location_t location)
26133 {
26139 /* Make sure we don't append the type to the template twice. */
26146 }
26148 /* Convert the generic type parameters in PARM that match the types given in the
26149 range [START_IDX, END_IDX) from the current_template_parms into generic type
26150 packs. */
26152 tree
26154 {
26165 {
26166 /* Create a distinct parameter pack type from the current parm and add it
26167 to the replacement args to tsubst below into the generic function
26168 parameter. */
26183 }
26189 /* If there are more levels then build up the replacement with the outer
26190 template parms. */
26194 replacement);
26197 }
26199 /* Entries in the decl_constraint hash table. */
26201 {
26202 tree decl;
26203 tree ci;
26204 };
26206 /* Hashing function and equality for constraint entries. */
26208 {
26210 {
26212 }
26215 {
26217 }
26218 };
26220 /* A mapping from declarations to constraint information. Note that
26221 both templates and their underlying declarations are mapped to the
26222 same constraint information.
26224 FIXME: This is defined in pt.c because garbage collection
26225 code is not being generated for constraint.cc. */
26229 /* Returns the template constraints of declaration T. If T is not
26230 constrained, return NULL_TREE. Note that T must be non-null. */
26232 tree
26234 {
26245 else
26247 }
26249 /* Associate the given constraint information CI with the declaration
26250 T. If T is a template, then the constraints are associated with
26251 its underlying declaration. Don't build associations if CI is
26252 NULL_TREE. */
26254 void
26256 {
26268 }
26270 /* Remove the associated constraints of the declaration T. */
26272 void
26274 {
26283 }
26285 /* Memoized satisfaction results for declarations. This
26286 maps the pair (constraint_info, arguments) to the result computed
26287 by constraints_satisfied_p. */
26290 {
26291 tree ci;
26292 tree args;
26293 tree result;
26294 };
26296 /* Hashing function and equality for constraint entries. */
26299 {
26301 {
26304 }
26307 {
26309 }
26310 };
26312 /* Memoized satisfaction results for concept checks. */
26315 {
26316 tree tmpl;
26317 tree args;
26318 tree result;
26319 };
26321 /* Hashing function and equality for constraint entries. */
26324 {
26326 {
26328 }
26331 {
26336 }
26337 };
26342 /* Search for a memoized satisfaction result. Returns one of the
26343 truth value nodes if previously memoized, or NULL_TREE otherwise. */
26345 tree
26347 {
26352 else
26354 }
26356 /* Memoize the result of a satisfication test. Returns the saved result. */
26358 tree
26360 {
26367 }
26369 /* Search for a memoized satisfaction result for a concept. */
26371 tree
26373 {
26378 else
26380 }
26382 /* Memoize the result of a concept check. Returns the saved result. */
26384 tree
26386 {
26393 }
26397 /* Returns a prior concept specialization. This returns the substituted
26398 and normalized constraints defined by the concept. */
26400 tree
26402 {
26407 else
26409 }
26411 /* Save a concept expansion for later. */
26413 tree
26415 {
26422 }
26424 static hashval_t
26426 {
26435 }
26437 /* Compare the constraints of two subsumption entries. The LEFT1 and
26438 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
26439 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
26441 static bool
26443 {
26451 }
26453 /* Key/value pair for learning and memoizing subsumption results. This
26454 associates a pair of check constraints (including arguments) with
26455 a boolean value indicating the result. */
26458 {
26459 tree t1;
26460 tree t2;
26462 };
26464 /* Hashing function and equality for constraint entries. */
26467 {
26469 {
26471 }
26474 {
26479 }
26480 };
26484 /* Search for a previously cached subsumption result. */
26488 {
26493 else
26495 }
26497 /* Save a subsumption result. */
26499 bool
26501 {
26508 }
26510 /* Set up the hash table for constraint association. */
26512 void
26514 {
26523 }
26525 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
26526 0..N-1. */
26528 void
26530 {
26533 integer_type_node,
26534 NULL_TREE),
26538 }
26540 /* Set up the hash tables for template instantiations. */
26542 void
26544 {
26550 }
26552 /* Print stats about the template hash tables for -fstats. */
26554 void
26556 {
26565 }